Update Cargo.toml

New [network] section + ME Fixes + small bugs coverage

.github/codeql/codeql-config.yml

@@ -0,0 +1,19 @@
+name: "Rust without tests"
+
+disable-default-queries: false
+
+queries:
+  - uses: security-extended
+  - uses: security-and-quality
+  - uses: ./.github/codeql/queries
+
+query-filters:
+  - exclude:
+      id:
+        - rust/unwrap-on-option
+        - rust/unwrap-on-result
+        - rust/expect-used
+
+analysis:
+  dataflow:
+    default-precision: high

.github/workflows/codeql.yml

@@ -2,9 +2,9 @@ name: "CodeQL Advanced"
 
 on:
   push:
-    branches: [ "main" ]
+    branches: [ "*" ]
   pull_request:
-    branches: [ "main" ]
+    branches: [ "*" ]
   schedule:
     - cron: '0 0 * * 0'
 

.github/workflows/rust.yml

@@ -2,9 +2,9 @@ name: Rust
 
 on:
   push:
-    branches: [ main ]
+    branches: [ "*" ]
   pull_request:
-    branches: [ main ]
+    branches: [ "*" ]
 
 env:
   CARGO_TERM_COLOR: always
@@ -42,5 +42,13 @@ jobs:
     - name: Build Release
       run: cargo build --release --verbose
 
+    - name: Run tests
+      run: cargo test --verbose
+
+# clippy dont fail on warnings because of active development of telemt 
+# and many warnings
+    - name: Run clippy
+      run: cargo clippy -- --cap-lints warn
+
     - name: Check for unused dependencies
       run: cargo udeps || true

.kilocode/rules-architect/AGENTS.md

@@ -0,0 +1,58 @@
+# Architect Mode Rules for Telemt
+
+## Architecture Overview
+
+```mermaid
+graph TB
+    subgraph Entry
+        Client[Clients] --> Listener[TCP/Unix Listener]
+    end
+    
+    subgraph Proxy Layer
+        Listener --> ClientHandler[ClientHandler]
+        ClientHandler --> Handshake[Handshake Validator]
+        Handshake --> |Valid| Relay[Relay Layer]
+        Handshake --> |Invalid| Masking[Masking/TLS Fronting]
+    end
+    
+    subgraph Transport
+        Relay --> MiddleProxy[Middle-End Proxy Pool]
+        Relay --> DirectRelay[Direct DC Relay]
+        MiddleProxy --> TelegramDC[Telegram DCs]
+        DirectRelay --> TelegramDC
+    end
+```
+
+## Module Dependencies
+- [`src/main.rs`](src/main.rs) - Entry point, spawns all async tasks
+- [`src/config/`](src/config/) - Configuration loading with auto-migration
+- [`src/error.rs`](src/error.rs) - Error types, must be used by all modules
+- [`src/crypto/`](src/crypto/) - AES, SHA, random number generation
+- [`src/protocol/`](src/protocol/) - MTProto constants, frame encoding, obfuscation
+- [`src/stream/`](src/stream/) - Stream wrappers, buffer pool, frame codecs
+- [`src/proxy/`](src/proxy/) - Client handling, handshake, relay logic
+- [`src/transport/`](src/transport/) - Upstream management, middle-proxy, SOCKS support
+- [`src/stats/`](src/stats/) - Statistics and replay protection
+- [`src/ip_tracker.rs`](src/ip_tracker.rs) - Per-user IP tracking
+
+## Key Architectural Constraints
+
+### Middle-End Proxy Mode
+- Requires public IP on interface OR 1:1 NAT with STUN probing
+- Uses separate `proxy-secret` from Telegram (NOT user secrets)
+- Falls back to direct mode automatically on STUN mismatch
+
+### TLS Fronting
+- Invalid handshakes are transparently proxied to `mask_host`
+- This is critical for DPI evasion - do not change this behavior
+- `mask_unix_sock` and `mask_host` are mutually exclusive
+
+### Stream Architecture
+- Buffer pool is shared globally via Arc - prevents allocation storms
+- Frame codecs implement tokio-util Encoder/Decoder traits
+- State machine in [`src/stream/state.rs`](src/stream/state.rs) manages stream transitions
+
+### Configuration Migration
+- [`ProxyConfig::load()`](src/config/mod.rs:641) mutates config in-place
+- New fields must have sensible defaults
+- DC203 override is auto-injected for CDN/media support

.kilocode/rules-code/AGENTS.md

@@ -0,0 +1,23 @@
+# Code Mode Rules for Telemt
+
+## Error Handling
+- Always use [`ProxyError`](src/error.rs:168) from [`src/error.rs`](src/error.rs) for proxy operations
+- [`HandshakeResult<T,R,W>`](src/error.rs:292) returns streams on bad client - these MUST be returned for masking, never dropped
+- Use [`Recoverable`](src/error.rs:110) trait to check if errors are retryable
+
+## Configuration Changes
+- [`ProxyConfig::load()`](src/config/mod.rs:641) auto-mutates config - new fields should have defaults
+- DC203 override is auto-injected if missing - do not remove this behavior
+- When adding config fields, add migration logic in [`ProxyConfig::load()`](src/config/mod.rs:641)
+
+## Crypto Code
+- [`SecureRandom`](src/crypto/random.rs) from [`src/crypto/random.rs`](src/crypto/random.rs) must be used for all crypto operations
+- Never use `rand::thread_rng()` directly - use the shared `Arc<SecureRandom>`
+
+## Stream Handling
+- Buffer pool [`BufferPool`](src/stream/buffer_pool.rs) is shared via Arc - always use it instead of allocating
+- Frame codecs in [`src/stream/frame_codec.rs`](src/stream/frame_codec.rs) implement tokio-util's Encoder/Decoder traits
+
+## Testing
+- Tests are inline in modules using `#[cfg(test)]`
+- Use `cargo test --lib <module_name>` to run tests for specific modules

.kilocode/rules-debug/AGENTS.md

@@ -0,0 +1,27 @@
+# Debug Mode Rules for Telemt
+
+## Logging
+- `RUST_LOG` environment variable takes absolute priority over all config log levels
+- Log levels: `trace`, `debug`, `info`, `warn`, `error`
+- Use `RUST_LOG=debug cargo run` for detailed operational logs
+- Use `RUST_LOG=trace cargo run` for full protocol-level debugging
+
+## Middle-End Proxy Debugging
+- Set `ME_DIAG=1` environment variable for high-precision cryptography diagnostics
+- STUN probe results are logged at startup - check for mismatch between local and reflected IP
+- If Middle-End fails, check `proxy_secret_path` points to valid file from https://core.telegram.org/getProxySecret
+
+## Connection Issues
+- DC connectivity is logged at startup with RTT measurements
+- If DC ping fails, check `dc_overrides` for custom addresses
+- Use `prefer_ipv6=false` in config if IPv6 is unreliable
+
+## TLS Fronting Issues
+- Invalid handshakes are proxied to `mask_host` - check this host is reachable
+- `mask_unix_sock` and `mask_host` are mutually exclusive - only one can be set
+- If `mask_unix_sock` is set, socket must exist before connections arrive
+
+## Common Errors
+- `ReplayAttack` - client replayed a handshake nonce, potential attack
+- `TimeSkew` - client clock is off, can disable with `ignore_time_skew=true`
+- `TgHandshakeTimeout` - upstream DC connection failed, check network

AGENTS.md

@@ -0,0 +1,40 @@
+# AGENTS.md
+
+** Use general system promt from AGENTS_SYSTEM_PROMT.md **
+** Additional techiques and architectury details are here **
+
+This file provides guidance to agents when working with code in this repository.
+
+## Build & Test Commands
+```bash
+cargo build --release          # Production build
+cargo test                     # Run all tests
+cargo test --lib error         # Run tests for specific module (error module)
+cargo bench --bench crypto_bench  # Run crypto benchmarks
+cargo clippy -- -D warnings    # Lint with clippy
+```
+
+## Project-Specific Conventions
+
+### Rust Edition
+- Uses **Rust edition 2024** (not 2021) - specified in Cargo.toml
+
+### Error Handling Pattern
+- Custom [`Recoverable`](src/error.rs:110) trait distinguishes recoverable vs fatal errors
+- [`HandshakeResult<T,R,W>`](src/error.rs:292) returns streams on bad client for masking - do not drop them
+- Always use [`ProxyError`](src/error.rs:168) from [`src/error.rs`](src/error.rs) for proxy operations
+
+### Configuration Auto-Migration
+- [`ProxyConfig::load()`](src/config/mod.rs:641) mutates config with defaults and migrations
+- DC203 override is auto-injected if missing (required for CDN/media)
+- `show_link` top-level migrates to `general.links.show`
+
+### Middle-End Proxy Requirements
+- Requires public IP on interface OR 1:1 NAT with STUN probing
+- Falls back to direct mode on STUN/interface mismatch unless `stun_iface_mismatch_ignore=true`
+- Proxy-secret from Telegram is separate from user secrets
+
+### TLS Fronting Behavior
+- Invalid handshakes are transparently proxied to `mask_host` for DPI evasion
+- `fake_cert_len` is randomized at startup (1024-4096 bytes)
+- `mask_unix_sock` and `mask_host` are mutually exclusive

AGENTS_SYSTEM_PROMT.md

@@ -0,0 +1,207 @@
+## System Prompt — Production Rust Codebase: Modification and Architecture Guidelines
+
+You are a senior Rust systems engineer acting as a strict code reviewer and implementation partner. Your responses are precise, minimal, and architecturally sound. You are working on a production-grade Rust codebase: follow these rules strictly.
+
+---
+
+### 0. Priority Resolution — Scope Control
+
+This section resolves conflicts between code quality enforcement and scope limitation.
+
+When editing or extending existing code, you MUST audit the affected files and fix:
+
+- Comment style violations (missing, non-English, decorative, trailing).
+- Missing or incorrect documentation on public items.
+- Comment placement issues (trailing comments → move above the code).
+
+These are **coordinated changes** — they are always in scope.
+
+The following changes are FORBIDDEN without explicit user approval:
+
+- Renaming types, traits, functions, modules, or variables.
+- Altering business logic, control flow, or data transformations.
+- Changing module boundaries, architectural layers, or public API surface.
+- Adding or removing functions, structs, enums, or trait implementations.
+- Fixing compiler warnings or removing unused code.
+
+If such issues are found during your work, list them under a `## ⚠️ Out-of-scope observations` section at the end of your response. Include file path, context, and a brief description. Do not apply these changes.
+
+The user can override this behavior with explicit commands:
+
+- `"Do not modify existing code"` — touch only what was requested, skip coordinated fixes.
+- `"Make minimal changes"` — no coordinated fixes, narrowest possible diff.
+- `"Fix everything"` — apply all coordinated fixes and out-of-scope observations.
+
+---
+
+### 1. Comments and Documentation
+
+- All comments MUST be written in English.
+- Write only comments that add technical value: architecture decisions, intent, invariants, non-obvious implementation details.
+- Place all comments on separate lines above the relevant code.
+- Use `///` doc-comments for public items. Use `//` for internal clarifications.
+
+Correct example:
+
+```rust
+// Handles MTProto client authentication and establishes encrypted session state.
+fn handle_authenticated_client(...) { ... }
+```
+
+Incorrect examples:
+
+```rust
+let x = 5; // set x to 5
+```
+
+```rust
+// This function does stuff
+fn do_stuff() { ... }
+```
+
+---
+
+### 2. File Size and Module Structure
+
+- Files MUST NOT exceed 350–550 lines.
+- If a file exceeds this limit, split it into submodules organized by responsibility (e.g., protocol, transport, state, handlers).
+- Parent modules MUST declare and describe their submodules.
+- Maintain clear architectural boundaries between modules.
+
+Correct example:
+
+```rust
+// Client connection handling logic.
+// Submodules:
+// - handshake: MTProto handshake implementation
+// - relay: traffic forwarding logic
+// - state: client session state machine
+
+pub mod handshake;
+pub mod relay;
+pub mod state;
+```
+
+Git discipline:
+
+- Use local git for versioning and diffs.
+- Write clear, descriptive commit messages in English that explain both *what* changed and *why*.
+
+---
+
+### 3. Formatting
+
+- Preserve the existing formatting style of the project exactly as-is.
+- Reformat code only when explicitly instructed to do so.
+- Do not run `cargo fmt` unless explicitly instructed.
+
+---
+
+### 4. Change Safety and Validation
+
+- If anything is unclear, STOP and ask specific, targeted questions before proceeding.
+- List exactly what is ambiguous and offer possible interpretations for the user to choose from.
+- Prefer clarification over assumptions. Do not guess intent, behavior, or missing requirements.
+- Actively ask questions before making architectural or behavioral changes.
+
+---
+
+### 5. Warnings and Unused Code
+
+- Leave all warnings, unused variables, functions, imports, and dead code untouched unless explicitly instructed to modify them.
+- These may be intentional or part of work-in-progress code.
+- `todo!()` and `unimplemented!()` are permitted and should not be removed or replaced unless explicitly instructed.
+
+---
+
+### 6. Architectural Integrity
+
+- Preserve existing architecture unless explicitly instructed to refactor.
+- Do not introduce hidden behavioral changes.
+- Do not introduce implicit refactors.
+- Keep changes minimal, isolated, and intentional.
+
+---
+
+### 7. When Modifying Code
+
+You MUST:
+
+- Maintain architectural consistency with the existing codebase.
+- Document non-obvious logic with comments that describe *why*, not *what*.
+- Limit changes strictly to the requested scope (plus coordinated fixes per Section 0).
+- Keep all existing symbol names unless renaming is explicitly requested.
+- Preserve global formatting as-is.
+
+You MUST NOT:
+
+- Use placeholders: no `// ... rest of code`, no `// implement here`, no `/* TODO */` stubs that replace existing working code. Write full, working implementation. If the implementation is unclear, ask first.
+- Refactor code outside the requested scope.
+- Make speculative improvements.
+
+Note: `todo!()` and `unimplemented!()` are allowed as idiomatic Rust markers for genuinely unfinished code paths.
+
+---
+
+### 8. Decision Process for Complex Changes
+
+When facing a non-trivial modification, follow this sequence:
+
+1. **Clarify**: Restate the task in one sentence to confirm understanding.
+2. **Assess impact**: Identify which modules, types, and invariants are affected.
+3. **Propose**: Describe the intended change before implementing it.
+4. **Implement**: Make the minimal, isolated change.
+5. **Verify**: Explain why the change preserves existing behavior and architectural integrity.
+
+---
+
+### 9. Context Awareness
+
+- When provided with partial code, assume the rest of the codebase exists and functions correctly unless stated otherwise.
+- Reference existing types, functions, and module structures by their actual names as shown in the provided code.
+- When the provided context is insufficient to make a safe change, request the missing context explicitly.
+
+---
+
+### 10. Response Format
+
+#### Language Policy
+
+- Code, comments, commit messages, documentation: **English**.
+- Reasoning and explanations in response text: **Russian**.
+
+#### Response Structure
+
+Your response MUST consist of two sections:
+
+**Section 1: `## Reasoning` (in Russian)**
+
+- What needs to be done and why.
+- Which files and modules are affected.
+- Architectural decisions and their rationale.
+- Potential risks or side effects.
+
+**Section 2: `## Changes`**
+
+- For each modified or created file: the filename on a separate line in backticks, followed by the code block.
+- For files **under 200 lines**: return the full file with all changes applied.
+- For files **over 200 lines**: return only the changed functions/blocks with at least 3 lines of surrounding context above and below. If the user requests the full file, provide it.
+- New files: full file content.
+- End with a suggested git commit message in English.
+
+#### Reporting Out-of-Scope Issues
+
+If during modification you discover issues outside the requested scope (potential bugs, unsafe code, architectural concerns, missing error handling, unused imports, dead code):
+
+- Do not fix them silently.
+- List them under `## ⚠️ Out-of-scope observations` at the end of your response.
+- Include: file path, line/function context, brief description of the issue, and severity estimate.
+
+#### Splitting Protocol
+
+If the response exceeds the output limit:
+
+1. End the current part with: **SPLIT: PART N — CONTINUE? (remaining: file_list)**
+2. List the files that will be provided in subsequent parts.
+3. Wait for user confirmation before continuing.
+4. No single file may be split across parts.

Cargo.lock

@@ -437,6 +437,12 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d9c4f5dac5e15c24eb999c26181a6ca40b39fe946cbe4c263c7209467bc83af2"
 
+[[package]]
+name = "foldhash"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77ce24cb58228fbb8aa041425bb1050850ac19177686ea6e0f41a70416f56fdb"
+
 [[package]]
 name = "form_urlencoded"
 version = "1.2.2"
@@ -585,6 +591,25 @@ dependencies = [
  "wasip3",
 ]
 
+[[package]]
+name = "h2"
+version = "0.4.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2f44da3a8150a6703ed5d34e164b875fd14c2cdab9af1252a9a1020bde2bdc54"
+dependencies = [
+ "atomic-waker",
+ "bytes",
+ "fnv",
+ "futures-core",
+ "futures-sink",
+ "http",
+ "indexmap",
+ "slab",
+ "tokio",
+ "tokio-util",
+ "tracing",
+]
+
 [[package]]
 name = "half"
 version = "2.7.1"
@@ -608,9 +633,7 @@ version = "0.15.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9229cfe53dfd69f0609a49f65461bd93001ea1ef889cd5529dd176593f5338a1"
 dependencies = [
- "allocator-api2",
+ "foldhash 0.1.5",
- "equivalent",
- "foldhash",
 ]
 
 [[package]]
@@ -618,6 +641,11 @@ name = "hashbrown"
 version = "0.16.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "841d1cc9bed7f9236f321df977030373f4a4163ae1a7dbfe1a51a2c1a51d9100"
+dependencies = [
+ "allocator-api2",
+ "equivalent",
+ "foldhash 0.2.0",
+]
 
 [[package]]
 name = "heck"
@@ -685,6 +713,12 @@ version = "1.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6dbf3de79e51f3d586ab4cb9d5c3e2c14aa28ed23d180cf89b4df0454a69cc87"
 
+[[package]]
+name = "httpdate"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df3b46402a9d5adb4c86a0cf463f42e19994e3ee891101b1841f30a545cb49a9"
+
 [[package]]
 name = "hyper"
 version = "1.8.1"
@@ -695,9 +729,11 @@ dependencies = [
  "bytes",
  "futures-channel",
  "futures-core",
+ "h2",
  "http",
  "http-body",
  "httparse",
+ "httpdate",
  "itoa",
  "pin-project-lite",
  "pin-utils",
@@ -999,11 +1035,11 @@ checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
 
 [[package]]
 name = "lru"
-version = "0.12.5"
+version = "0.16.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "234cf4f4a04dc1f57e24b96cc0cd600cf2af460d4161ac5ecdd0af8e1f3b2a38"
+checksum = "a1dc47f592c06f33f8e3aea9591776ec7c9f9e4124778ff8a3c3b87159f7e593"
 dependencies = [
- "hashbrown 0.15.5",
+ "hashbrown 0.16.1",
 ]
 
 [[package]]
@@ -1057,6 +1093,25 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "num-bigint"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a5e44f723f1133c9deac646763579fdb3ac745e418f2a7af9cd0c431da1f20b9"
+dependencies = [
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.46"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7969661fd2958a5cb096e56c8e1ad0444ac2bbcd0061bd28660485a44879858f"
+dependencies = [
+ "num-traits",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.19"
@@ -1714,7 +1769,7 @@ dependencies = [
 
 [[package]]
 name = "telemt"
-version = "1.2.0"
+version = "3.0.0"
 dependencies = [
  "aes",
  "base64",
@@ -1729,9 +1784,15 @@ dependencies = [
  "futures",
  "hex",
  "hmac",
+ "http-body-util",
+ "httpdate",
+ "hyper",
+ "hyper-util",
  "libc",
  "lru",
  "md-5",
+ "num-bigint",
+ "num-traits",
  "parking_lot",
  "proptest",
  "rand",
@@ -1899,8 +1960,12 @@ checksum = "9ae9cec805b01e8fc3fd2fe289f89149a9b66dd16786abd8b19cfa7b48cb0098"
 dependencies = [
  "bytes",
  "futures-core",
+ "futures-io",
  "futures-sink",
+ "futures-util",
+ "hashbrown 0.15.5",
  "pin-project-lite",
+ "slab",
  "tokio",
 ]
 

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "telemt"
-version = "1.2.0"
+version = "3.0.2"
 edition = "2024"
 
 [dependencies]
@@ -9,7 +9,7 @@ libc = "0.2"
 
 # Async runtime
 tokio = { version = "1.42", features = ["full", "tracing"] }
-tokio-util = { version = "0.7", features = ["codec"] }
+tokio-util = { version = "0.7", features = ["full"] }
 
 # Crypto
 aes = "0.8"
@@ -37,7 +37,7 @@ tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 parking_lot = "0.12"
 dashmap = "5.5"
-lru = "0.12"
+lru = "0.16"
 rand = "0.9"
 chrono = { version = "0.4", features = ["serde"] }
 hex = "0.4"
@@ -45,9 +45,15 @@ base64 = "0.22"
 url = "2.5"
 regex = "1.11"
 crossbeam-queue = "0.3"
+num-bigint = "0.4"
+num-traits = "0.2"
 
 # HTTP
 reqwest = { version = "0.12", features = ["rustls-tls"], default-features = false }
+hyper = { version = "1", features = ["server", "http1"] }
+hyper-util = { version = "0.1", features = ["tokio", "server-auto"] }
+http-body-util = "0.1"
+httpdate = "1.0"
 
 [dev-dependencies]
 tokio-test = "0.4"

Dockerfile

@@ -0,0 +1,43 @@
+# ==========================
+# Stage 1: Build
+# ==========================
+FROM rust:1.85-slim-bookworm AS builder
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    pkg-config \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /build
+
+COPY Cargo.toml Cargo.lock* ./
+RUN mkdir src && echo 'fn main() {}' > src/main.rs && \
+    cargo build --release 2>/dev/null || true && \
+    rm -rf src
+
+COPY . .
+RUN cargo build --release && strip target/release/telemt
+
+# ==========================
+# Stage 2: Runtime
+# ==========================
+FROM debian:bookworm-slim
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN useradd -r -s /usr/sbin/nologin telemt
+
+WORKDIR /app
+
+COPY --from=builder /build/target/release/telemt /app/telemt
+COPY config.toml /app/config.toml
+
+RUN chown -R telemt:telemt /app
+USER telemt
+
+EXPOSE 443
+EXPOSE 9090
+
+ENTRYPOINT ["/app/telemt"]
+CMD ["config.toml"]

README.md

@@ -2,27 +2,89 @@
 
 **Telemt** is a fast, secure, and feature-rich server written in Rust: it fully implements the official Telegram proxy algo and adds many production-ready improvements such as connection pooling, replay protection, detailed statistics, masking from "prying" eyes
 
-## Emergency
+## NEWS and EMERGENCY
-**Важное сообщение для пользователей из России**
+### ✈️ Telemt 3 is released!
+<table>
+<tr>
+<td width="50%" valign="top">
 
-Мы работаем над проектом с Нового года и сейчас готовим новый релиз - 1.2
+### 🇷🇺 RU
 
-В нём имплементируется поддержка Middle Proxy Protocol - основного терминатора для Ad Tag:
+15 февраля мы опубликовали `telemt 3` с поддержкой Middle-End Proxy, а значит:
-работа над ним идёт с 6 ферваля, а уже 10 февраля произошли "громкие события"...
 
-Если у вас есть компетенции в асинхронных сетевых приложениях - мы открыты к предложениям и pull requests
+- с функциональными медиа, в том числе с CDN/DC=203  
+- с Ad-tag — показывайте спонсорский канал и собирайте статистику через официального бота  
+- с новым подходом к безопасности и асинхронности  
+- с высокоточной диагностикой криптографии через `ME_DIAG`  
 
-**Important message for users from Russia**
+Для использования нужно:
 
-We've been working on the project since December 30 and are currently preparing a new release – 1.2
+1. Версия `telemt` ≥3.0.0
+2. Выполнение любого из наборов условий:
+   - публичный IP для исходящих соединений установлен на интерфейса инстанса с `telemt`
+     - ЛИБО
+   - вы используете NAT 1:1 + включили STUN-пробинг
+3. В конфиге, в секции `[general]` указать:
+```toml
+use_middle_proxy = true
+```
 
-It implements support for the Middle Proxy Protocol – the primary point for the Ad Tag:
+Если условия из пункта 1 не выполняются:
-development on it started on February 6th, and by February 10th, "big activity" in Russia had already "taken place"...
+1. Выключите ME-режим:
+   - установите `use_middle_proxy = false`
+     - ЛИБО
+   - Middle-End Proxy будет выключен автоматически по таймауту, но это займёт больше времени при запуске
+2. В конфиге, добавьте в конец:
+```toml
+[dc_overrides]
+"203" = "91.105.192.100:443"
+```
 
-If you have expertise in asynchronous network applications – we are open to ideas and pull requests!
+Если у вас есть компетенции в асинхронных сетевых приложениях, анализе трафика, реверс-инжиниринге или сетевых расследованиях — мы открыты к идеям и pull requests.
+
+</td>
+<td width="50%" valign="top">
+
+### 🇬🇧 EN
+
+On February 15, we released `telemt 3` with support for Middle-End Proxy, which means:
+
+- functional media, including CDN/DC=203  
+- Ad-tag support – promote a sponsored channel and collect statistics via Telegram bot  
+- new approach to security and asynchronicity  
+- high-precision cryptography diagnostics via `ME_DIAG`  
+
+To use this feature, the following requirements must be met:
+1. `telemt` version ≥ 3.0.0
+2. One of the following conditions satisfied:
+   - the instance running `telemt` has a public IP address assigned to its network interface for outbound connections  
+     - OR
+   - you are using 1:1 NAT and have STUN probing enabled  
+3. In the config file, under the `[general]` section, specify:
+```toml
+use_middle_proxy = true
+````
+
+If the conditions from step 1 are not satisfied:
+1. Disable Middle-End mode:
+   - set `use_middle_proxy = false`
+     - OR
+   - Middle-End Proxy will be disabled automatically after a timeout, but this will increase startup time
+
+2. In the config file, add the following at the end:
+```toml
+[dc_overrides]
+"203" = "91.105.192.100:443"
+```
+
+If you have expertise in asynchronous network applications, traffic analysis, reverse engineering, or network forensics — we welcome ideas, suggestions, and pull requests.
+
+</td>
+</tr>
+</table>
 
 # Features
-💥 The configuration structure has changed since version 1.1.0.0, change it in your environment!
+💥 The configuration structure has changed since version 1.1.0.0. change it in your environment!
 
 ⚓ Our implementation of **TLS-fronting** is one of the most deeply debugged, focused, advanced and *almost* **"behaviorally consistent to real"**:  we are confident we have it right - [see evidence on our validation and traces](#recognizability-for-dpi-and-crawler) 
 
@@ -44,7 +106,9 @@ If you have expertise in asynchronous network applications – we are open to id
   - [Telegram Calls](#telegram-calls-via-mtproxy)
   - [DPI](#how-does-dpi-see-mtproxy-tls)
   - [Whitelist on Network Level](#whitelist-on-ip)
+  - [Too many open files](#too-many-open-files)
 - [Build](#build)
+- [Docker](#docker)
 - [Why Rust?](#why-rust)
 
 ## Features
@@ -128,6 +192,7 @@ Type=simple
 WorkingDirectory=/bin
 ExecStart=/bin/telemt /etc/telemt.toml
 Restart=on-failure
+LimitNOFILE=65536
 
 [Install]
 WantedBy=multi-user.target
@@ -143,17 +208,20 @@ then Ctrl+X -> Y -> Enter to save
 ## Configuration
 ### Minimal Configuration for First Start
 ```toml
-# === UI ===
-# Users to show in the startup log (tg:// links)
-show_link = ["hello"]
-
 # === General Settings ===
 [general]
+# prefer_ipv6 is deprecated; use [network].prefer
 prefer_ipv6 = false
 fast_mode = true
 use_middle_proxy = false
 # ad_tag = "..."
 
+[network]
+ipv4 = true
+ipv6 = true   # set false to disable, omit for auto
+prefer = 4    # 4 or 6
+multipath = false
+
 [general.modes]
 classic = false
 secure = false
@@ -170,11 +238,19 @@ listen_addr_ipv6 = "::"
 # Listen on multiple interfaces/IPs (overrides listen_addr_*)
 [[server.listeners]]
 ip = "0.0.0.0"
-# announce_ip = "1.2.3.4" # Optional: Public IP for tg:// links
+# announce = "my.hostname.tld" # Optional: hostname for tg:// links
+# OR
+# announce = "1.2.3.4" # Optional: Public IP for tg:// links
 
 [[server.listeners]]
 ip = "::"
 
+# Users to show in the startup log (tg:// links)
+[general.links]
+show = ["hello"] # Users to show in the startup log (tg:// links)
+# public_host = "proxy.example.com"  # Host (IP or domain) for tg:// links
+# public_port = 443                  # Port for tg:// links (default: server.port)
+
 # === Timeouts (in seconds) ===
 [timeouts]
 client_handshake = 15
@@ -222,6 +298,10 @@ weight = 10
 # address = "127.0.0.1:9050"
 # enabled = false
 # weight = 1
+
+# === DC Address Overrides ===
+# [dc_overrides]
+# "203" = "91.105.192.100:443"
 ```
 ### Advanced
 #### Adtag
@@ -377,6 +457,23 @@ Keep-Alive: timeout=60
   - in China behind the Great Firewall
   - in Russia on mobile networks, less in wired networks
   - in Iran during "activity"
+### Too many open files
+- On a fresh Linux install the default open file limit is low; under load `telemt` may fail with `Accept error: Too many open files`
+- **Systemd**: add `LimitNOFILE=65536` to the `[Service]` section (already included in the example above)
+- **Docker**: add `--ulimit nofile=65536:65536` to your `docker run` command, or in `docker-compose.yml`:
+```yaml
+ulimits:
+  nofile:
+    soft: 65536
+    hard: 65536
+```
+- **System-wide** (optional): add to `/etc/security/limits.conf`:
+```
+*       soft    nofile  1048576
+*       hard    nofile  1048576
+root    soft    nofile  1048576
+root    hard    nofile  1048576
+```
 
 
 ## Build
@@ -395,9 +492,44 @@ chmod +x /bin/telemt
 telemt config.toml
 ```
 
+## Docker
+**Quick start (Docker Compose)**
+
+1. Edit `config.toml` in repo root (at least: port, users secrets, tls_domain)
+2. Start container:
+```bash
+docker compose up -d --build
+```
+3. Check logs:
+```bash
+docker compose logs -f telemt
+```
+4. Stop:
+```bash
+docker compose down
+```
+
+**Notes**
+- `docker-compose.yml` maps `./config.toml` to `/app/config.toml` (read-only)
+- By default it publishes `443:443` and runs with dropped capabilities (only `NET_BIND_SERVICE` is added)
+- If you really need host networking (usually only for some IPv6 setups) uncomment `network_mode: host`
+
+**Run without Compose**
+```bash
+docker build -t telemt:local .
+docker run --name telemt --restart unless-stopped \
+  -p 443:443 \
+  -e RUST_LOG=info \
+  -v "$PWD/config.toml:/app/config.toml:ro" \
+  --read-only \
+  --cap-drop ALL --cap-add NET_BIND_SERVICE \
+  --ulimit nofile=65536:65536 \
+  telemt:local
+```
+
 ## Why Rust?
 - Long-running reliability and idempotent behavior
-- Rust’s deterministic resource management - RAII 
+- Rust's deterministic resource management - RAII 
 - No garbage collector
 - Memory safety and reduced attack surface
 - Tokio's asynchronous architecture

config.toml

@@ -1,13 +1,18 @@
-# === UI ===
-# Users to show in the startup log (tg:// links)
-show_link = ["hello"]
-
 # === General Settings ===
 [general]
+# prefer_ipv6 is deprecated; use [network].prefer instead
 prefer_ipv6 = false
 fast_mode = true
 use_middle_proxy = true
-ad_tag = "00000000000000000000000000000000"
+#ad_tag = "00000000000000000000000000000000"
+
+[network]
+# Enable/disable families; ipv6 = true/false/auto(None)
+ipv4 = true
+ipv6 = true
+# prefer = 4 or 6
+prefer = 4
+multipath = false
 
 # Log level: debug | verbose | normal | silent
 # Can be overridden with --silent or --log-level CLI flags
@@ -24,6 +29,8 @@ tls = true
 port = 443
 listen_addr_ipv4 = "0.0.0.0"
 listen_addr_ipv6 = "::"
+# listen_unix_sock = "/var/run/telemt.sock" # Unix socket
+# listen_unix_sock_perm = "0666" # Socket file permissions
 # metrics_port = 9090
 # metrics_whitelist = ["127.0.0.1", "::1"]
 
@@ -35,6 +42,12 @@ ip = "0.0.0.0"
 [[server.listeners]]
 ip = "::"
 
+# Users to show in the startup log (tg:// links)
+[general.links]
+show = ["hello"] # Users to show in the startup log (tg:// links)
+# public_host = "proxy.example.com"  # Host (IP or domain) for tg:// links
+# public_port = 443                  # Port for tg:// links (default: server.port)
+
 # === Timeouts (in seconds) ===
 [timeouts]
 client_handshake = 15
@@ -64,6 +77,9 @@ hello = "00000000000000000000000000000000"
 # [access.user_max_tcp_conns]
 # hello = 50
 
+# [access.user_max_unique_ips]
+# hello = 5
+
 # [access.user_data_quota]
 # hello = 1073741824 # 1 GB
 
@@ -78,3 +94,7 @@ weight = 10
 # address = "127.0.0.1:1080"
 # enabled = false
 # weight = 1
+
+# === DC Address Overrides ===
+# [dc_overrides]
+# "203" = "91.105.192.100:443"

docker-compose.yml

@@ -0,0 +1,29 @@
+services:
+  telemt:
+    build: .
+    container_name: telemt
+    restart: unless-stopped
+    ports:
+      - "443:443"
+      - "9090:9090"
+    # Allow caching 'proxy-secret' in read-only container
+    working_dir: /run/telemt
+    volumes:
+      - ./config.toml:/run/telemt/config.toml:ro
+    tmpfs:
+      - /run/telemt:rw,mode=1777,size=1m
+    environment:
+      - RUST_LOG=info
+    # Uncomment this line if you want to use host network for IPv6, but bridge is default and usually better
+    # network_mode: host
+    cap_drop:
+      - ALL
+    cap_add:
+      - NET_BIND_SERVICE   # allow binding to port 443
+    read_only: true
+    security_opt:
+      - no-new-privileges:true
+    ulimits:
+      nofile:
+        soft: 65536
+        hard: 65536

src/cli.rs

@@ -189,11 +189,18 @@ r#"# Telemt MTProxy — auto-generated config
 show_link = ["{username}"]
 
 [general]
+# prefer_ipv6 is deprecated; use [network].prefer
 prefer_ipv6 = false
 fast_mode = true
 use_middle_proxy = false
 log_level = "normal"
 
+[network]
+ipv4 = true
+ipv6 = true
+prefer = 4
+multipath = false
+
 [general.modes]
 classic = false
 secure = false

src/config/mod.rs

@@ -3,9 +3,11 @@
 use crate::error::{ProxyError, Result};
 use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
+use serde::de::Deserializer;
 use std::collections::HashMap;
-use std::net::{IpAddr, SocketAddr};
+use std::net::IpAddr;
 use std::path::Path;
+use tracing::warn;
 
 // ============= Helper Defaults =============
 
@@ -52,6 +54,44 @@ fn default_metrics_whitelist() -> Vec<IpAddr> {
     vec!["127.0.0.1".parse().unwrap(), "::1".parse().unwrap()]
 }
 
+fn default_prefer_4() -> u8 {
+    4
+}
+
+fn default_unknown_dc_log_path() -> Option<String> {
+    Some("unknown-dc.txt".to_string())
+}
+
+// ============= Custom Deserializers =============
+
+#[derive(Deserialize)]
+#[serde(untagged)]
+enum OneOrMany {
+    One(String),
+    Many(Vec<String>),
+}
+
+fn deserialize_dc_overrides<'de, D>(
+    deserializer: D,
+) -> std::result::Result<HashMap<String, Vec<String>>, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    let raw: HashMap<String, OneOrMany> = HashMap::deserialize(deserializer)?;
+    let mut out = HashMap::new();
+    for (dc, val) in raw {
+        let mut addrs = match val {
+            OneOrMany::One(s) => vec![s],
+            OneOrMany::Many(v) => v,
+        };
+        addrs.retain(|s| !s.trim().is_empty());
+        if !addrs.is_empty() {
+            out.insert(dc, addrs);
+        }
+    }
+    Ok(out)
+}
+
 // ============= Log Level =============
 
 /// Logging verbosity level
@@ -94,6 +134,50 @@ impl LogLevel {
     }
 }
 
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn dc_overrides_allow_string_and_array() {
+        let toml = r#"
+            [dc_overrides]
+            "201" = "149.154.175.50:443"
+            "202" = ["149.154.167.51:443", "149.154.175.100:443"]
+        "#;
+        let cfg: ProxyConfig = toml::from_str(toml).unwrap();
+        assert_eq!(cfg.dc_overrides["201"], vec!["149.154.175.50:443"]);
+        assert_eq!(
+            cfg.dc_overrides["202"],
+            vec!["149.154.167.51:443", "149.154.175.100:443"]
+        );
+    }
+
+    #[test]
+    fn dc_overrides_inject_dc203_default() {
+        let toml = r#"
+            [general]
+            use_middle_proxy = false
+
+            [censorship]
+            tls_domain = "example.com"
+
+            [access.users]
+            user = "00000000000000000000000000000000"
+        "#;
+        let dir = std::env::temp_dir();
+        let path = dir.join("telemt_dc_override_test.toml");
+        std::fs::write(&path, toml).unwrap();
+        let cfg = ProxyConfig::load(&path).unwrap();
+        assert!(cfg
+            .dc_overrides
+            .get("203")
+            .map(|v| v.contains(&"91.105.192.100:443".to_string()))
+            .unwrap_or(false));
+        let _ = std::fs::remove_file(path);
+    }
+}
+
 impl std::fmt::Display for LogLevel {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
@@ -105,6 +189,32 @@ impl std::fmt::Display for LogLevel {
     }
 }
 
+fn validate_network_cfg(net: &mut NetworkConfig) -> Result<()> {
+    if !net.ipv4 && matches!(net.ipv6, Some(false)) {
+        return Err(ProxyError::Config(
+            "Both ipv4 and ipv6 are disabled in [network]".to_string(),
+        ));
+    }
+
+    if net.prefer != 4 && net.prefer != 6 {
+        return Err(ProxyError::Config(
+            "network.prefer must be 4 or 6".to_string(),
+        ));
+    }
+
+    if !net.ipv4 && net.prefer == 4 {
+        warn!("prefer=4 but ipv4=false; forcing prefer=6");
+        net.prefer = 6;
+    }
+
+    if matches!(net.ipv6, Some(false)) && net.prefer == 6 {
+        warn!("prefer=6 but ipv6=false; forcing prefer=4");
+        net.prefer = 4;
+    }
+
+    Ok(())
+}
+
 // ============= Sub-Configs =============
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -127,6 +237,34 @@ impl Default for ProxyModes {
     }
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct NetworkConfig {
+    #[serde(default = "default_true")]
+    pub ipv4: bool,
+
+    /// None = auto-detect IPv6 availability
+    #[serde(default)]
+    pub ipv6: Option<bool>,
+
+    /// 4 or 6
+    #[serde(default = "default_prefer_4")]
+    pub prefer: u8,
+
+    #[serde(default)]
+    pub multipath: bool,
+}
+
+impl Default for NetworkConfig {
+    fn default() -> Self {
+        Self {
+            ipv4: true,
+            ipv6: None,
+            prefer: 4,
+            multipath: false,
+        }
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct GeneralConfig {
     #[serde(default)]
@@ -162,8 +300,41 @@ pub struct GeneralConfig {
     #[serde(default)]
     pub middle_proxy_nat_stun: Option<String>,
 
+    /// Ignore STUN/interface IP mismatch (keep using Middle Proxy even if NAT detected).
+    #[serde(default)]
+    pub stun_iface_mismatch_ignore: bool,
+
+    /// Log unknown (non-standard) DC requests to a file (default: unknown-dc.txt). Set to null to disable.
+    #[serde(default = "default_unknown_dc_log_path")]
+    pub unknown_dc_log_path: Option<String>,
+
     #[serde(default)]
     pub log_level: LogLevel,
+
+    /// Disable colored output in logs (useful for files/systemd)
+    #[serde(default)]
+    pub disable_colors: bool,
+
+    /// [general.links] — proxy link generation overrides
+    #[serde(default)]
+    pub links: LinksConfig,
+}
+
+/// `[general.links]` — proxy link generation settings.
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+pub struct LinksConfig {
+    /// List of usernames whose tg:// links to display at startup.
+    /// `"*"` = all users, `["alice", "bob"]` = specific users.
+    #[serde(default)]
+    pub show: ShowLink,
+
+    /// Public hostname/IP for tg:// link generation (overrides detected IP).
+    #[serde(default)]
+    pub public_host: Option<String>,
+
+    /// Public port for tg:// link generation (overrides server.port).
+    #[serde(default)]
+    pub public_port: Option<u16>,
 }
 
 impl Default for GeneralConfig {
@@ -178,7 +349,11 @@ impl Default for GeneralConfig {
             middle_proxy_nat_ip: None,
             middle_proxy_nat_probe: false,
             middle_proxy_nat_stun: None,
+            stun_iface_mismatch_ignore: false,
+            unknown_dc_log_path: default_unknown_dc_log_path(),
             log_level: LogLevel::Normal,
+            disable_colors: false,
+            links: LinksConfig::default(),
         }
     }
 }
@@ -188,8 +363,8 @@ pub struct ServerConfig {
     #[serde(default = "default_port")]
     pub port: u16,
 
-    #[serde(default = "default_listen_addr")]
+    #[serde(default)]
-    pub listen_addr_ipv4: String,
+    pub listen_addr_ipv4: Option<String>,
 
     #[serde(default)]
     pub listen_addr_ipv6: Option<String>,
@@ -197,6 +372,16 @@ pub struct ServerConfig {
     #[serde(default)]
     pub listen_unix_sock: Option<String>,
 
+    /// Unix socket file permissions (octal, e.g. "0666" or "0777").
+    /// Applied via chmod after bind. Default: no change (inherits umask).
+    #[serde(default)]
+    pub listen_unix_sock_perm: Option<String>,
+
+    /// Enable TCP listening. Default: true when no unix socket, false when
+    /// listen_unix_sock is set. Set explicitly to override auto-detection.
+    #[serde(default)]
+    pub listen_tcp: Option<bool>,
+
     #[serde(default)]
     pub metrics_port: Option<u16>,
 
@@ -211,9 +396,11 @@ impl Default for ServerConfig {
     fn default() -> Self {
         Self {
             port: default_port(),
-            listen_addr_ipv4: default_listen_addr(),
+            listen_addr_ipv4: Some(default_listen_addr()),
             listen_addr_ipv6: Some("::".to_string()),
             listen_unix_sock: None,
+            listen_unix_sock_perm: None,
+            listen_tcp: None,
             metrics_port: None,
             metrics_whitelist: default_metrics_whitelist(),
             listeners: Vec::new(),
@@ -295,6 +482,9 @@ pub struct AccessConfig {
     #[serde(default)]
     pub user_data_quota: HashMap<String, u64>,
 
+    #[serde(default)]
+    pub user_max_unique_ips: HashMap<String, usize>,
+
     #[serde(default = "default_replay_check_len")]
     pub replay_check_len: usize,
 
@@ -317,6 +507,7 @@ impl Default for AccessConfig {
             user_max_tcp_conns: HashMap::new(),
             user_expirations: HashMap::new(),
             user_data_quota: HashMap::new(),
+            user_max_unique_ips: HashMap::new(),
             replay_check_len: default_replay_check_len(),
             replay_window_secs: default_replay_window_secs(),
             ignore_time_skew: false,
@@ -364,10 +555,111 @@ pub struct UpstreamConfig {
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ListenerConfig {
     pub ip: IpAddr,
+    /// IP address or hostname to announce in proxy links.
+    /// Takes precedence over `announce_ip` if both are set.
+    #[serde(default)]
+    pub announce: Option<String>,
+    /// Deprecated: Use `announce` instead. IP address to announce in proxy links.
+    /// Migrated to `announce` automatically if `announce` is not set.
     #[serde(default)]
     pub announce_ip: Option<IpAddr>,
 }
 
+// ============= ShowLink =============
+
+/// Controls which users' proxy links are displayed at startup.
+///
+/// In TOML, this can be:
+/// - `show_link = "*"`          — show links for all users
+/// - `show_link = ["a", "b"]`   — show links for specific users
+/// - omitted                    — show no links (default)
+#[derive(Debug, Clone)]
+pub enum ShowLink {
+    /// Don't show any links (default when omitted)
+    None,
+    /// Show links for all configured users
+    All,
+    /// Show links for specific users
+    Specific(Vec<String>),
+}
+
+impl Default for ShowLink {
+    fn default() -> Self {
+        ShowLink::None
+    }
+}
+
+impl ShowLink {
+    /// Returns true if no links should be shown
+    pub fn is_empty(&self) -> bool {
+        matches!(self, ShowLink::None) || matches!(self, ShowLink::Specific(v) if v.is_empty())
+    }
+
+    /// Resolve the list of user names to display, given all configured users
+    pub fn resolve_users<'a>(&'a self, all_users: &'a HashMap<String, String>) -> Vec<&'a String> {
+        match self {
+            ShowLink::None => vec![],
+            ShowLink::All => {
+                let mut names: Vec<&String> = all_users.keys().collect();
+                names.sort();
+                names
+            }
+            ShowLink::Specific(names) => names.iter().collect(),
+        }
+    }
+}
+
+impl Serialize for ShowLink {
+    fn serialize<S: serde::Serializer>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error> {
+        match self {
+            ShowLink::None => Vec::<String>::new().serialize(serializer),
+            ShowLink::All => serializer.serialize_str("*"),
+            ShowLink::Specific(v) => v.serialize(serializer),
+        }
+    }
+}
+
+impl<'de> Deserialize<'de> for ShowLink {
+    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> std::result::Result<Self, D::Error> {
+        use serde::de;
+
+        struct ShowLinkVisitor;
+
+        impl<'de> de::Visitor<'de> for ShowLinkVisitor {
+            type Value = ShowLink;
+
+            fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+                formatter.write_str(r#""*" or an array of user names"#)
+            }
+
+            fn visit_str<E: de::Error>(self, v: &str) -> std::result::Result<ShowLink, E> {
+                if v == "*" {
+                    Ok(ShowLink::All)
+                } else {
+                    Err(de::Error::invalid_value(
+                        de::Unexpected::Str(v),
+                        &r#""*""#,
+                    ))
+                }
+            }
+
+            fn visit_seq<A: de::SeqAccess<'de>>(self, mut seq: A) -> std::result::Result<ShowLink, A::Error> {
+                let mut names = Vec::new();
+                while let Some(name) = seq.next_element::<String>()? {
+                    names.push(name);
+                }
+                if names.is_empty() {
+                    Ok(ShowLink::None)
+                } else {
+                    Ok(ShowLink::Specific(names))
+                }
+            }
+        }
+
+        deserializer.deserialize_any(ShowLinkVisitor)
+    }
+}
+
 // ============= Main Config =============
 
 #[derive(Debug, Clone, Serialize, Deserialize, Default)]
@@ -375,6 +667,9 @@ pub struct ProxyConfig {
     #[serde(default)]
     pub general: GeneralConfig,
 
+    #[serde(default)]
+    pub network: NetworkConfig,
+
     #[serde(default)]
     pub server: ServerConfig,
 
@@ -391,16 +686,16 @@ pub struct ProxyConfig {
     pub upstreams: Vec<UpstreamConfig>,
 
     #[serde(default)]
-    pub show_link: Vec<String>,
+    pub show_link: ShowLink,
 
     /// DC address overrides for non-standard DCs (CDN, media, test, etc.)
-    /// Keys are DC indices as strings, values are "ip:port" addresses.
+    /// Keys are DC indices as strings, values are one or more \"ip:port\" addresses.
     /// Matches the C implementation's `proxy_for <dc_id> <ip>:<port>` config directive.
     /// Example in config.toml:
     ///   [dc_overrides]
-    ///   "203" = "149.154.175.100:443"
+    ///   \"203\" = [\"149.154.175.100:443\", \"91.105.192.100:443\"]
-    #[serde(default)]
+    #[serde(default, deserialize_with = "deserialize_dc_overrides")]
-    pub dc_overrides: HashMap<String, String>,
+    pub dc_overrides: HashMap<String, Vec<String>>,
 
     /// Default DC index (1-5) for unmapped non-standard DCs.
     /// Matches the C implementation's `default <dc_id>` config directive.
@@ -463,15 +758,42 @@ impl ProxyConfig {
             config.censorship.mask_host = Some(config.censorship.tls_domain.clone());
         }
 
+        // Migration: prefer_ipv6 -> network.prefer
+        if config.general.prefer_ipv6 {
+            if config.network.prefer == 4 {
+                config.network.prefer = 6;
+            }
+            warn!("prefer_ipv6 is deprecated, use [network].prefer = 6");
+        }
+
+        validate_network_cfg(&mut config.network)?;
+
         // Random fake_cert_len
         use rand::Rng;
         config.censorship.fake_cert_len = rand::rng().gen_range(1024..4096);
 
-        // Migration: Populate listeners if empty
+        // Resolve listen_tcp: explicit value wins, otherwise auto-detect.
-        if config.server.listeners.is_empty() {
+        // If unix socket is set → TCP only when listen_addr_ipv4 or listeners are explicitly provided.
-            if let Ok(ipv4) = config.server.listen_addr_ipv4.parse::<IpAddr>() {
+        // If no unix socket → TCP always (backward compat).
+        let listen_tcp = config.server.listen_tcp.unwrap_or_else(|| {
+            if config.server.listen_unix_sock.is_some() {
+                // Unix socket present: TCP only if user explicitly set addresses or listeners
+                config.server.listen_addr_ipv4.is_some()
+                    || !config.server.listeners.is_empty()
+            } else {
+                true
+            }
+        });
+
+        // Migration: Populate listeners if empty (skip when listen_tcp = false)
+        if config.server.listeners.is_empty() && listen_tcp {
+            let ipv4_str = config.server.listen_addr_ipv4
+                .as_deref()
+                .unwrap_or("0.0.0.0");
+            if let Ok(ipv4) = ipv4_str.parse::<IpAddr>() {
                 config.server.listeners.push(ListenerConfig {
                     ip: ipv4,
+                    announce: None,
                     announce_ip: None,
                 });
             }
@@ -479,12 +801,25 @@ impl ProxyConfig {
                 if let Ok(ipv6) = ipv6_str.parse::<IpAddr>() {
                     config.server.listeners.push(ListenerConfig {
                         ip: ipv6,
+                        announce: None,
                         announce_ip: None,
                     });
                 }
             }
         }
 
+        // Migration: announce_ip → announce for each listener
+        for listener in &mut config.server.listeners {
+            if listener.announce.is_none() && listener.announce_ip.is_some() {
+                listener.announce = Some(listener.announce_ip.unwrap().to_string());
+            }
+        }
+
+        // Migration: show_link (top-level) → general.links.show
+        if !config.show_link.is_empty() && config.general.links.show.is_empty() {
+            config.general.links.show = config.show_link.clone();
+        }
+
         // Migration: Populate upstreams if empty (Default Direct)
         if config.upstreams.is_empty() {
             config.upstreams.push(UpstreamConfig {
@@ -494,6 +829,12 @@ impl ProxyConfig {
             });
         }
 
+        // Ensure default DC203 override is present.
+        config
+            .dc_overrides
+            .entry("203".to_string())
+            .or_insert_with(|| vec!["91.105.192.100:443".to_string()]);
+
         Ok(config)
     }
 
@@ -513,6 +854,16 @@ impl ProxyConfig {
             )));
         }
 
+        if let Some(tag) = &self.general.ad_tag {
+            let zeros = "00000000000000000000000000000000";
+            if tag == zeros {
+                warn!("ad_tag is all zeros; register a valid proxy tag via @MTProxybot to enable sponsored channel");
+            }
+            if tag.len() != 32 || tag.chars().any(|c| !c.is_ascii_hexdigit()) {
+                warn!("ad_tag is not a 32-char hex string; ensure you use value issued by @MTProxybot");
+            }
+        }
+
         Ok(())
     }
 }

src/crypto/hash.rs

@@ -172,7 +172,7 @@ mod tests {
         let digest = sha256(&prekey);
         assert_eq!(
             hex::encode(digest),
-            "a4595b75f1f610f2575ace802ddc65c91b5acef3b0e0d18189e0c7c9f787d15c"
+            "934f5facdafd65a44d5c2df90d2f35ddc81faaaeb337949dfeef817c8a7c1e00"
         );
     }
 }

src/ip_tracker.rs

@@ -0,0 +1,462 @@
+// src/ip_tracker.rs
+// Модуль для отслеживания и ограничения уникальных IP-адресов пользователей
+
+use std::collections::{HashMap, HashSet};
+use std::net::IpAddr;
+use std::sync::Arc;
+use tokio::sync::RwLock;
+
+/// Трекер уникальных IP-адресов для каждого пользователя MTProxy
+/// 
+/// Предоставляет thread-safe механизм для:
+/// - Отслеживания активных IP-адресов каждого пользователя
+/// - Ограничения количества уникальных IP на пользователя
+/// - Автоматической очистки при отключении клиентов
+#[derive(Debug, Clone)]
+pub struct UserIpTracker {
+    /// Маппинг: Имя пользователя -> Множество активных IP-адресов
+    active_ips: Arc<RwLock<HashMap<String, HashSet<IpAddr>>>>,
+    
+    /// Маппинг: Имя пользователя -> Максимально разрешенное количество уникальных IP
+    max_ips: Arc<RwLock<HashMap<String, usize>>>,
+}
+
+impl UserIpTracker {
+    /// Создать новый пустой трекер
+    pub fn new() -> Self {
+        Self {
+            active_ips: Arc::new(RwLock::new(HashMap::new())),
+            max_ips: Arc::new(RwLock::new(HashMap::new())),
+        }
+    }
+
+    /// Установить лимит уникальных IP для конкретного пользователя
+    /// 
+    /// # Arguments
+    /// * `username` - Имя пользователя
+    /// * `max_ips` - Максимальное количество одновременно активных IP-адресов
+    pub async fn set_user_limit(&self, username: &str, max_ips: usize) {
+        let mut limits = self.max_ips.write().await;
+        limits.insert(username.to_string(), max_ips);
+    }
+
+    /// Загрузить лимиты из конфигурации
+    /// 
+    /// # Arguments
+    /// * `limits` - HashMap с лимитами из config.toml
+    pub async fn load_limits(&self, limits: &HashMap<String, usize>) {
+        let mut max_ips = self.max_ips.write().await;
+        for (user, limit) in limits {
+            max_ips.insert(user.clone(), *limit);
+        }
+    }
+
+    /// Проверить, может ли пользователь подключиться с данного IP-адреса
+    /// и добавить IP в список активных, если проверка успешна
+    /// 
+    /// # Arguments
+    /// * `username` - Имя пользователя
+    /// * `ip` - IP-адрес клиента
+    /// 
+    /// # Returns
+    /// * `Ok(())` - Подключение разрешено, IP добавлен в активные
+    /// * `Err(String)` - Подключение отклонено с описанием причины
+    pub async fn check_and_add(&self, username: &str, ip: IpAddr) -> Result<(), String> {
+        // Получаем лимит для пользователя
+        let max_ips = self.max_ips.read().await;
+        let limit = match max_ips.get(username) {
+            Some(limit) => *limit,
+            None => {
+                // Если лимит не задан - разрешаем безлимитный доступ
+                drop(max_ips);
+                let mut active_ips = self.active_ips.write().await;
+                let user_ips = active_ips
+                    .entry(username.to_string())
+                    .or_insert_with(HashSet::new);
+                user_ips.insert(ip);
+                return Ok(());
+            }
+        };
+        drop(max_ips);
+
+        // Проверяем и обновляем активные IP
+        let mut active_ips = self.active_ips.write().await;
+        let user_ips = active_ips
+            .entry(username.to_string())
+            .or_insert_with(HashSet::new);
+
+        // Если IP уже есть в списке - это повторное подключение, разрешаем
+        if user_ips.contains(&ip) {
+            return Ok(());
+        }
+
+        // Проверяем, не превышен ли лимит
+        if user_ips.len() >= limit {
+            return Err(format!(
+                "IP limit reached for user '{}': {}/{} unique IPs already connected",
+                username,
+                user_ips.len(),
+                limit
+            ));
+        }
+
+        // Лимит не превышен - добавляем новый IP
+        user_ips.insert(ip);
+        Ok(())
+    }
+
+    /// Удалить IP-адрес из списка активных при отключении клиента
+    /// 
+    /// # Arguments
+    /// * `username` - Имя пользователя
+    /// * `ip` - IP-адрес отключившегося клиента
+    pub async fn remove_ip(&self, username: &str, ip: IpAddr) {
+        let mut active_ips = self.active_ips.write().await;
+        
+        if let Some(user_ips) = active_ips.get_mut(username) {
+            user_ips.remove(&ip);
+            
+            // Если у пользователя не осталось активных IP - удаляем запись
+            // для экономии памяти
+            if user_ips.is_empty() {
+                active_ips.remove(username);
+            }
+        }
+    }
+
+    /// Получить текущее количество активных IP-адресов для пользователя
+    /// 
+    /// # Arguments
+    /// * `username` - Имя пользователя
+    /// 
+    /// # Returns
+    /// Количество уникальных активных IP-адресов
+    pub async fn get_active_ip_count(&self, username: &str) -> usize {
+        let active_ips = self.active_ips.read().await;
+        active_ips
+            .get(username)
+            .map(|ips| ips.len())
+            .unwrap_or(0)
+    }
+
+    /// Получить список всех активных IP-адресов для пользователя
+    /// 
+    /// # Arguments
+    /// * `username` - Имя пользователя
+    /// 
+    /// # Returns
+    /// Вектор с активными IP-адресами
+    pub async fn get_active_ips(&self, username: &str) -> Vec<IpAddr> {
+        let active_ips = self.active_ips.read().await;
+        active_ips
+            .get(username)
+            .map(|ips| ips.iter().copied().collect())
+            .unwrap_or_else(Vec::new)
+    }
+
+    /// Получить статистику по всем пользователям
+    /// 
+    /// # Returns
+    /// Вектор кортежей: (имя_пользователя, количество_активных_IP, лимит)
+    pub async fn get_stats(&self) -> Vec<(String, usize, usize)> {
+        let active_ips = self.active_ips.read().await;
+        let max_ips = self.max_ips.read().await;
+
+        let mut stats = Vec::new();
+        
+        // Собираем статистику по пользователям с активными подключениями
+        for (username, user_ips) in active_ips.iter() {
+            let limit = max_ips.get(username).copied().unwrap_or(0);
+            stats.push((username.clone(), user_ips.len(), limit));
+        }
+        
+        stats.sort_by(|a, b| a.0.cmp(&b.0)); // Сортируем по имени пользователя
+        stats
+    }
+
+    /// Очистить все активные IP для пользователя (при необходимости)
+    /// 
+    /// # Arguments
+    /// * `username` - Имя пользователя
+    pub async fn clear_user_ips(&self, username: &str) {
+        let mut active_ips = self.active_ips.write().await;
+        active_ips.remove(username);
+    }
+
+    /// Очистить всю статистику (использовать с осторожностью!)
+    pub async fn clear_all(&self) {
+        let mut active_ips = self.active_ips.write().await;
+        active_ips.clear();
+    }
+
+    /// Проверить, подключен ли пользователь с данного IP
+    /// 
+    /// # Arguments
+    /// * `username` - Имя пользователя
+    /// * `ip` - IP-адрес для проверки
+    /// 
+    /// # Returns
+    /// `true` если IP активен, `false` если нет
+    pub async fn is_ip_active(&self, username: &str, ip: IpAddr) -> bool {
+        let active_ips = self.active_ips.read().await;
+        active_ips
+            .get(username)
+            .map(|ips| ips.contains(&ip))
+            .unwrap_or(false)
+    }
+
+    /// Получить лимит для пользователя
+    /// 
+    /// # Arguments
+    /// * `username` - Имя пользователя
+    /// 
+    /// # Returns
+    /// Лимит IP-адресов или None, если лимит не установлен
+    pub async fn get_user_limit(&self, username: &str) -> Option<usize> {
+        let max_ips = self.max_ips.read().await;
+        max_ips.get(username).copied()
+    }
+
+    /// Форматировать статистику в читаемый текст
+    /// 
+    /// # Returns
+    /// Строка со статистикой для логов или мониторинга
+    pub async fn format_stats(&self) -> String {
+        let stats = self.get_stats().await;
+        
+        if stats.is_empty() {
+            return String::from("No active users");
+        }
+        
+        let mut output = String::from("User IP Statistics:\n");
+        output.push_str("==================\n");
+        
+        for (username, active_count, limit) in stats {
+            output.push_str(&format!(
+                "User: {:<20} Active IPs: {}/{}\n",
+                username,
+                active_count,
+                if limit > 0 { limit.to_string() } else { "unlimited".to_string() }
+            ));
+            
+            let ips = self.get_active_ips(&username).await;
+            for ip in ips {
+                output.push_str(&format!("  └─ {}\n", ip));
+            }
+        }
+        
+        output
+    }
+}
+
+impl Default for UserIpTracker {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+// ============================================================================
+// ТЕСТЫ
+// ============================================================================
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+
+    fn test_ipv4(oct1: u8, oct2: u8, oct3: u8, oct4: u8) -> IpAddr {
+        IpAddr::V4(Ipv4Addr::new(oct1, oct2, oct3, oct4))
+    }
+
+    fn test_ipv6() -> IpAddr {
+        IpAddr::V6(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 1))
+    }
+
+    #[tokio::test]
+    async fn test_basic_ip_limit() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 2).await;
+
+        let ip1 = test_ipv4(192, 168, 1, 1);
+        let ip2 = test_ipv4(192, 168, 1, 2);
+        let ip3 = test_ipv4(192, 168, 1, 3);
+
+        // Первые два IP должны быть приняты
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ip2).await.is_ok());
+
+        // Третий IP должен быть отклонен
+        assert!(tracker.check_and_add("test_user", ip3).await.is_err());
+
+        // Проверяем счетчик
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 2);
+    }
+
+    #[tokio::test]
+    async fn test_reconnection_from_same_ip() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 2).await;
+
+        let ip1 = test_ipv4(192, 168, 1, 1);
+
+        // Первое подключение
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        
+        // Повторное подключение с того же IP должно пройти
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        
+        // Счетчик не должен увеличиться
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 1);
+    }
+
+    #[tokio::test]
+    async fn test_ip_removal() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 2).await;
+
+        let ip1 = test_ipv4(192, 168, 1, 1);
+        let ip2 = test_ipv4(192, 168, 1, 2);
+        let ip3 = test_ipv4(192, 168, 1, 3);
+
+        // Добавляем два IP
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ip2).await.is_ok());
+        
+        // Третий не должен пройти
+        assert!(tracker.check_and_add("test_user", ip3).await.is_err());
+
+        // Удаляем первый IP
+        tracker.remove_ip("test_user", ip1).await;
+        
+        // Теперь третий должен пройти
+        assert!(tracker.check_and_add("test_user", ip3).await.is_ok());
+        
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 2);
+    }
+
+    #[tokio::test]
+    async fn test_no_limit() {
+        let tracker = UserIpTracker::new();
+        // Не устанавливаем лимит для test_user
+
+        let ip1 = test_ipv4(192, 168, 1, 1);
+        let ip2 = test_ipv4(192, 168, 1, 2);
+        let ip3 = test_ipv4(192, 168, 1, 3);
+
+        // Без лимита все IP должны проходить
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ip2).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ip3).await.is_ok());
+        
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 3);
+    }
+
+    #[tokio::test]
+    async fn test_multiple_users() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("user1", 2).await;
+        tracker.set_user_limit("user2", 1).await;
+
+        let ip1 = test_ipv4(192, 168, 1, 1);
+        let ip2 = test_ipv4(192, 168, 1, 2);
+
+        // user1 может использовать 2 IP
+        assert!(tracker.check_and_add("user1", ip1).await.is_ok());
+        assert!(tracker.check_and_add("user1", ip2).await.is_ok());
+
+        // user2 может использовать только 1 IP
+        assert!(tracker.check_and_add("user2", ip1).await.is_ok());
+        assert!(tracker.check_and_add("user2", ip2).await.is_err());
+    }
+
+    #[tokio::test]
+    async fn test_ipv6_support() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 2).await;
+
+        let ipv4 = test_ipv4(192, 168, 1, 1);
+        let ipv6 = test_ipv6();
+
+        // Должны работать оба типа адресов
+        assert!(tracker.check_and_add("test_user", ipv4).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ipv6).await.is_ok());
+        
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 2);
+    }
+
+    #[tokio::test]
+    async fn test_get_active_ips() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 3).await;
+
+        let ip1 = test_ipv4(192, 168, 1, 1);
+        let ip2 = test_ipv4(192, 168, 1, 2);
+
+        tracker.check_and_add("test_user", ip1).await.unwrap();
+        tracker.check_and_add("test_user", ip2).await.unwrap();
+
+        let active_ips = tracker.get_active_ips("test_user").await;
+        assert_eq!(active_ips.len(), 2);
+        assert!(active_ips.contains(&ip1));
+        assert!(active_ips.contains(&ip2));
+    }
+
+    #[tokio::test]
+    async fn test_stats() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("user1", 3).await;
+        tracker.set_user_limit("user2", 2).await;
+
+        let ip1 = test_ipv4(192, 168, 1, 1);
+        let ip2 = test_ipv4(192, 168, 1, 2);
+
+        tracker.check_and_add("user1", ip1).await.unwrap();
+        tracker.check_and_add("user2", ip2).await.unwrap();
+
+        let stats = tracker.get_stats().await;
+        assert_eq!(stats.len(), 2);
+        
+        // Проверяем наличие обоих пользователей в статистике
+        assert!(stats.iter().any(|(name, _, _)| name == "user1"));
+        assert!(stats.iter().any(|(name, _, _)| name == "user2"));
+    }
+
+    #[tokio::test]
+    async fn test_clear_user_ips() {
+        let tracker = UserIpTracker::new();
+        let ip1 = test_ipv4(192, 168, 1, 1);
+        
+        tracker.check_and_add("test_user", ip1).await.unwrap();
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 1);
+        
+        tracker.clear_user_ips("test_user").await;
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 0);
+    }
+
+    #[tokio::test]
+    async fn test_is_ip_active() {
+        let tracker = UserIpTracker::new();
+        let ip1 = test_ipv4(192, 168, 1, 1);
+        let ip2 = test_ipv4(192, 168, 1, 2);
+        
+        tracker.check_and_add("test_user", ip1).await.unwrap();
+        
+        assert!(tracker.is_ip_active("test_user", ip1).await);
+        assert!(!tracker.is_ip_active("test_user", ip2).await);
+    }
+
+    #[tokio::test]
+    async fn test_load_limits_from_config() {
+        let tracker = UserIpTracker::new();
+        
+        let mut config_limits = HashMap::new();
+        config_limits.insert("user1".to_string(), 5);
+        config_limits.insert("user2".to_string(), 3);
+        
+        tracker.load_limits(&config_limits).await;
+        
+        assert_eq!(tracker.get_user_limit("user1").await, Some(5));
+        assert_eq!(tracker.get_user_limit("user2").await, Some(3));
+        assert_eq!(tracker.get_user_limit("user3").await, None);
+    }
+}

src/main.rs

@@ -8,11 +8,16 @@ use tokio::signal;
 use tokio::sync::Semaphore;
 use tracing::{debug, error, info, warn};
 use tracing_subscriber::{EnvFilter, fmt, prelude::*, reload};
+#[cfg(unix)]
+use tokio::net::UnixListener;
 
 mod cli;
 mod config;
 mod crypto;
 mod error;
+mod ip_tracker;
+mod network;
+mod metrics;
 mod protocol;
 mod proxy;
 mod stats;
@@ -22,12 +27,15 @@ mod util;
 
 use crate::config::{LogLevel, ProxyConfig};
 use crate::crypto::SecureRandom;
+use crate::ip_tracker::UserIpTracker;
+use crate::network::probe::{decide_network_capabilities, log_probe_result, run_probe};
 use crate::proxy::ClientHandler;
 use crate::stats::{ReplayChecker, Stats};
 use crate::stream::BufferPool;
-use crate::transport::middle_proxy::MePool;
+use crate::transport::middle_proxy::{
+    MePool, fetch_proxy_config, run_me_ping, MePingFamily, MePingSample, format_sample_line,
+};
 use crate::transport::{ListenOptions, UpstreamManager, create_listener};
-use crate::util::ip::detect_ip;
 
 fn parse_cli() -> (String, bool, Option<String>) {
     let mut config_path = "config.toml".to_string();
@@ -97,6 +105,37 @@ fn parse_cli() -> (String, bool, Option<String>) {
     (config_path, silent, log_level)
 }
 
+fn print_proxy_links(host: &str, port: u16, config: &ProxyConfig) {
+    info!("--- Proxy Links ({}) ---", host);
+    for user_name in config.general.links.show.resolve_users(&config.access.users) {
+        if let Some(secret) = config.access.users.get(user_name) {
+            info!("User: {}", user_name);
+            if config.general.modes.classic {
+                info!(
+                    "  Classic: tg://proxy?server={}&port={}&secret={}",
+                    host, port, secret
+                );
+            }
+            if config.general.modes.secure {
+                info!(
+                    "  DD:      tg://proxy?server={}&port={}&secret=dd{}",
+                    host, port, secret
+                );
+            }
+            if config.general.modes.tls {
+                let domain_hex = hex::encode(&config.censorship.tls_domain);
+                info!(
+                    "  EE-TLS:  tg://proxy?server={}&port={}&secret=ee{}{}",
+                    host, port, secret, domain_hex
+                );
+            }
+        } else {
+            warn!("User '{}' in show_link not found", user_name);
+        }
+    }
+    info!("------------------------");
+}
+
 #[tokio::main]
 async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
     let (config_path, cli_silent, cli_log_level) = parse_cli();
@@ -131,13 +170,24 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
     };
 
     let (filter_layer, filter_handle) = reload::Layer::new(EnvFilter::new("info"));
+    
+    // Configure color output based on config
+    let fmt_layer = if config.general.disable_colors {
+        fmt::Layer::default().with_ansi(false)
+    } else {
+        fmt::Layer::default().with_ansi(true)
+    };
+    
     tracing_subscriber::registry()
         .with(filter_layer)
-        .with(fmt::Layer::default())
+        .with(fmt_layer)
         .init();
 
     info!("Telemt MTProxy v{}", env!("CARGO_PKG_VERSION"));
     info!("Log level: {}", effective_log_level);
+    if config.general.disable_colors {
+        info!("Colors: disabled");
+    }
     info!(
         "Modes: classic={} secure={} tls={}",
         config.general.modes.classic, config.general.modes.secure, config.general.modes.tls
@@ -168,8 +218,17 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
         warn!("Using default tls_domain. Consider setting a custom domain.");
     }
 
-    let prefer_ipv6 = config.general.prefer_ipv6;
+    let probe = run_probe(
-    let use_middle_proxy = config.general.use_middle_proxy;
+        &config.network,
+        config.general.middle_proxy_nat_stun.clone(),
+        config.general.middle_proxy_nat_probe,
+    )
+    .await?;
+    let decision = decide_network_capabilities(&config.network, &probe);
+    log_probe_result(&probe, &decision);
+
+    let prefer_ipv6 = decision.prefer_ipv6();
+    let mut use_middle_proxy = config.general.use_middle_proxy && (decision.ipv4_me || decision.ipv6_me);
     let config = Arc::new(config);
     let stats = Arc::new(Stats::new());
     let rng = Arc::new(SecureRandom::new());
@@ -182,9 +241,22 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
     let upstream_manager = Arc::new(UpstreamManager::new(config.upstreams.clone()));
     let buffer_pool = Arc::new(BufferPool::with_config(16 * 1024, 4096));
 
+    // IP Tracker initialization
+    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.load_limits(&config.access.user_max_unique_ips).await;
+    
+    if !config.access.user_max_unique_ips.is_empty() {
+        info!("IP limits configured for {} users", config.access.user_max_unique_ips.len());
+    }
+
     // Connection concurrency limit
     let _max_connections = Arc::new(Semaphore::new(10_000));
 
+    if use_middle_proxy && !decision.ipv4_me && !decision.ipv6_me {
+        warn!("No usable IP family for Middle Proxy detected; falling back to direct DC");
+        use_middle_proxy = false;
+    }
+
     // =====================================================================
     // Middle Proxy initialization (if enabled)
     // =====================================================================
@@ -209,10 +281,10 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
         // proxy-secret is from: https://core.telegram.org/getProxySecret
         // =============================================================
         let proxy_secret_path = config.general.proxy_secret_path.as_deref();
-        match crate::transport::middle_proxy::fetch_proxy_secret(proxy_secret_path).await {
+match crate::transport::middle_proxy::fetch_proxy_secret(proxy_secret_path).await {
     Ok(proxy_secret) => {
         info!(
-                    secret_len = proxy_secret.len(),
+            secret_len = proxy_secret.len() as usize,  // ← ЯВНЫЙ ТИП usize
             key_sig = format_args!(
                 "0x{:08x}",
                 if proxy_secret.len() >= 4 {
@@ -229,12 +301,36 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
             "Proxy-secret loaded"
         );
 
+                // Load ME config (v4/v6) + default DC
+                let mut cfg_v4 = fetch_proxy_config(
+                    "https://core.telegram.org/getProxyConfig",
+                )
+                .await
+                .unwrap_or_default();
+                let mut cfg_v6 = fetch_proxy_config(
+                    "https://core.telegram.org/getProxyConfigV6",
+                )
+                .await
+                .unwrap_or_default();
+
+                if cfg_v4.map.is_empty() {
+                    cfg_v4.map = crate::protocol::constants::TG_MIDDLE_PROXIES_V4.clone();
+                }
+                if cfg_v6.map.is_empty() {
+                    cfg_v6.map = crate::protocol::constants::TG_MIDDLE_PROXIES_V6.clone();
+                }
+
                 let pool = MePool::new(
                     proxy_tag,
                     proxy_secret,
                     config.general.middle_proxy_nat_ip,
                     config.general.middle_proxy_nat_probe,
                     config.general.middle_proxy_nat_stun.clone(),
+                    cfg_v4.map.clone(),
+                    cfg_v6.map.clone(),
+                    cfg_v4.default_dc.or(cfg_v6.default_dc),
+                    decision.clone(),
+                    rng.clone(),
                 );
 
                 match pool.init(2, &rng).await {
@@ -251,6 +347,30 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
                             .await;
                         });
 
+                        // Periodic ME connection rotation
+                        let pool_clone_rot = pool.clone();
+                        let rng_clone_rot = rng.clone();
+                        tokio::spawn(async move {
+                            crate::transport::middle_proxy::me_rotation_task(
+                                pool_clone_rot,
+                                rng_clone_rot,
+                                std::time::Duration::from_secs(1800),
+                            )
+                            .await;
+                        });
+
+                        // Periodic updater: getProxyConfig + proxy-secret
+                        let pool_clone2 = pool.clone();
+                        let rng_clone2 = rng.clone();
+                        tokio::spawn(async move {
+                            crate::transport::middle_proxy::me_config_updater(
+                                pool_clone2,
+                                rng_clone2,
+                                std::time::Duration::from_secs(12 * 3600),
+                            )
+                            .await;
+                        });
+
                         Some(pool)
                     }
                     Err(e) => {
@@ -269,26 +389,88 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
     };
 
     if me_pool.is_some() {
-        info!("Transport: Middle Proxy (supports all DCs including CDN)");
+        info!("Transport: Middle-End Proxy - all DC-over-RPC");
     } else {
-        info!("Transport: Direct TCP (standard DCs only)");
+        info!("Transport: Direct DC - TCP - standard DC-over-TCP");
+    }
+
+    // Middle-End ping before DC connectivity
+    if let Some(ref pool) = me_pool {
+        let me_results = run_me_ping(pool, &rng).await;
+
+        let v4_ok = me_results.iter().any(|r| {
+            matches!(r.family, MePingFamily::V4)
+                && r.samples.iter().any(|s| s.error.is_none() && s.handshake_ms.is_some())
+        });
+        let v6_ok = me_results.iter().any(|r| {
+            matches!(r.family, MePingFamily::V6)
+                && r.samples.iter().any(|s| s.error.is_none() && s.handshake_ms.is_some())
+        });
+
+        info!("================= Telegram ME Connectivity =================");
+        if v4_ok && v6_ok {
+            info!("  IPv4 and IPv6 available");
+        } else if v4_ok {
+            info!("  IPv4 only / IPv6 unavailable");
+        } else if v6_ok {
+            info!("  IPv6 only / IPv4 unavailable");
+        } else {
+            info!("  No ME connectivity");
+        }
+        info!("  via direct");
+        info!("============================================================");
+
+        use std::collections::BTreeMap;
+        let mut grouped: BTreeMap<i32, Vec<MePingSample>> = BTreeMap::new();
+        for report in me_results {
+            for s in report.samples {
+                let key = s.dc.abs();
+                grouped.entry(key).or_default().push(s);
+            }
+        }
+
+        let family_order = if prefer_ipv6 {
+            vec![(MePingFamily::V6, true), (MePingFamily::V6, false), (MePingFamily::V4, true), (MePingFamily::V4, false)]
+        } else {
+            vec![(MePingFamily::V4, true), (MePingFamily::V4, false), (MePingFamily::V6, true), (MePingFamily::V6, false)]
+        };
+
+        for (dc_abs, samples) in grouped {
+            for (family, is_pos) in &family_order {
+                let fam_samples: Vec<&MePingSample> = samples
+                    .iter()
+                    .filter(|s| matches!(s.family, f if &f == family) && (s.dc >= 0) == *is_pos)
+                    .collect();
+                if fam_samples.is_empty() {
+                    continue;
+                }
+
+                let fam_label = match family {
+                    MePingFamily::V4 => "IPv4",
+                    MePingFamily::V6 => "IPv6",
+                };
+                info!("    DC{} [{}]", dc_abs, fam_label);
+                for sample in fam_samples {
+                    let line = format_sample_line(sample);
+                    info!("{}", line);
+                }
+            }
+        }
+        info!("============================================================");
     }
 
-    // Startup DC ping (only meaningful in direct mode)
-    if me_pool.is_none() {
     info!("================= Telegram DC Connectivity =================");
 
-        let ping_results = upstream_manager.ping_all_dcs(prefer_ipv6).await;
+    let ping_results = upstream_manager
+        .ping_all_dcs(
+            prefer_ipv6,
+            &config.dc_overrides,
+            decision.ipv4_dc,
+            decision.ipv6_dc,
+        )
+        .await;
 
 	for upstream_result in &ping_results {
-            // Show which IP version is in use and which is fallback
-            if upstream_result.both_available {
-                if prefer_ipv6 {
-                    info!("  IPv6 in use and IPv4 is fallback");
-                } else {
-                    info!("  IPv4 in use and IPv6 is fallback");
-                }
-            } else {
 		let v6_works = upstream_result
 			.v6_results
 			.iter()
@@ -297,45 +479,52 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
 			.v4_results
 			.iter()
 			.any(|r| r.rtt_ms.is_some());
+		
+		if upstream_result.both_available {
+			if prefer_ipv6 {
+				info!("  IPv6 in use / IPv4 is fallback");
+			} else {
+				info!("  IPv4 in use / IPv6 is fallback");
+			}
+		} else {
 			if v6_works && !v4_works {
-                    info!("  IPv6 only (IPv4 unavailable)");
+				info!("  IPv6 only / IPv4 unavailable)");
 			} else if v4_works && !v6_works {
-                    info!("  IPv4 only (IPv6 unavailable)");
+				info!("  IPv4 only / IPv6 unavailable)");
 			} else if !v6_works && !v4_works {
-                    info!("  No connectivity!");
+				info!("  No DC connectivity");
 			}
 		}
 
 		info!("  via {}", upstream_result.upstream_name);
 		info!("============================================================");
 
-            // Print IPv6 results first
+		// Print IPv6 results first (only if IPv6 is available)
+		if v6_works {
 			for dc in &upstream_result.v6_results {
 				let addr_str = format!("{}:{}", dc.dc_addr.ip(), dc.dc_addr.port());
 				match &dc.rtt_ms {
 					Some(rtt) => {
-                        // Align: IPv6 addresses are longer, use fewer tabs
+						info!("    DC{} [IPv6] {} - {:.0} ms", dc.dc_idx, addr_str, rtt);
-                        // [2001:b28:f23d:f001::a]:443 = ~28 chars
-                        info!("    DC{} [IPv6] {}:\t\t{:.0} ms", dc.dc_idx, addr_str, rtt);
 					}
 					None => {
 						let err = dc.error.as_deref().unwrap_or("fail");
-                        info!("    DC{} [IPv6] {}:\t\tFAIL ({})", dc.dc_idx, addr_str, err);
+						info!("    DC{} [IPv6] {} - FAIL ({})", dc.dc_idx, addr_str, err);
 					}
 				}
 			}
 
 			info!("============================================================");
+		}
 
-            // Print IPv4 results
+		// Print IPv4 results (only if IPv4 is available)
+		if v4_works {
 			for dc in &upstream_result.v4_results {
 				let addr_str = format!("{}:{}", dc.dc_addr.ip(), dc.dc_addr.port());
 				match &dc.rtt_ms {
 					Some(rtt) => {
-                        // Align: IPv4 addresses are shorter, use more tabs
-                        // 149.154.175.50:443 = ~18 chars
 						info!(
-                            "    DC{} [IPv4] {}:\t\t\t\t{:.0} ms",
+							"    DC{} [IPv4] {}\t\t\t\t{:.0} ms",
 							dc.dc_idx, addr_str, rtt
 						);
 					}
@@ -355,8 +544,15 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
 
     // Background tasks
     let um_clone = upstream_manager.clone();
+    let decision_clone = decision.clone();
     tokio::spawn(async move {
-        um_clone.run_health_checks(prefer_ipv6).await;
+        um_clone
+            .run_health_checks(
+                prefer_ipv6,
+                decision_clone.ipv4_dc,
+                decision_clone.ipv6_dc,
+            )
+            .await;
     });
 
     let rc_clone = replay_checker.clone();
@@ -364,16 +560,31 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
         rc_clone.run_periodic_cleanup().await;
     });
 
-    let detected_ip = detect_ip().await;
+    let detected_ip_v4: Option<std::net::IpAddr> = probe
+        .reflected_ipv4
+        .map(|s| s.ip())
+        .or_else(|| probe.detected_ipv4.map(std::net::IpAddr::V4));
+    let detected_ip_v6: Option<std::net::IpAddr> = probe
+        .reflected_ipv6
+        .map(|s| s.ip())
+        .or_else(|| probe.detected_ipv6.map(std::net::IpAddr::V6));
     debug!(
         "Detected IPs: v4={:?} v6={:?}",
-        detected_ip.ipv4, detected_ip.ipv6
+        detected_ip_v4, detected_ip_v6
     );
 
     let mut listeners = Vec::new();
 
     for listener_conf in &config.server.listeners {
         let addr = SocketAddr::new(listener_conf.ip, config.server.port);
+        if addr.is_ipv4() && !decision.ipv4_dc {
+            warn!(%addr, "Skipping IPv4 listener: IPv4 disabled by [network]");
+            continue;
+        }
+        if addr.is_ipv6() && !decision.ipv6_dc {
+            warn!(%addr, "Skipping IPv6 listener: IPv6 disabled by [network]");
+            continue;
+        }
         let options = ListenOptions {
             ipv6_only: listener_conf.ip.is_ipv6(),
             ..Default::default()
@@ -384,47 +595,28 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
                 let listener = TcpListener::from_std(socket.into())?;
                 info!("Listening on {}", addr);
 
-                let public_ip = if let Some(ip) = listener_conf.announce_ip {
+                // Resolve the public host for link generation
-                    ip
+                let public_host = if let Some(ref announce) = listener_conf.announce {
+                    announce.clone()  // Use announce (IP or hostname) if explicitly set
                 } else if listener_conf.ip.is_unspecified() {
+                    // Auto-detect for unspecified addresses
                     if listener_conf.ip.is_ipv4() {
-                        detected_ip.ipv4.unwrap_or(listener_conf.ip)
+                        detected_ip_v4
+                            .map(|ip| ip.to_string())
+                            .unwrap_or_else(|| listener_conf.ip.to_string())
                     } else {
-                        detected_ip.ipv6.unwrap_or(listener_conf.ip)
+                        detected_ip_v6
+                            .map(|ip| ip.to_string())
+                            .unwrap_or_else(|| listener_conf.ip.to_string())
                     }
                 } else {
-                    listener_conf.ip
+                    listener_conf.ip.to_string()
                 };
 
-                if !config.show_link.is_empty() {
+                // Show per-listener proxy links only when public_host is not set
-                    info!("--- Proxy Links ({}) ---", public_ip);
+                if config.general.links.public_host.is_none() && !config.general.links.show.is_empty() {
-                    for user_name in &config.show_link {
+                    let link_port = config.general.links.public_port.unwrap_or(config.server.port);
-                        if let Some(secret) = config.access.users.get(user_name) {
+                    print_proxy_links(&public_host, link_port, &config);
-                            info!("User: {}", user_name);
-                            if config.general.modes.classic {
-                                info!(
-                                    "  Classic: tg://proxy?server={}&port={}&secret={}",
-                                    public_ip, config.server.port, secret
-                                );
-                            }
-                            if config.general.modes.secure {
-                                info!(
-                                    "  DD:      tg://proxy?server={}&port={}&secret=dd{}",
-                                    public_ip, config.server.port, secret
-                                );
-                            }
-                            if config.general.modes.tls {
-                                let domain_hex = hex::encode(&config.censorship.tls_domain);
-                                info!(
-                                    "  EE-TLS:  tg://proxy?server={}&port={}&secret=ee{}{}",
-                                    public_ip, config.server.port, secret, domain_hex
-                                );
-                            }
-                        } else {
-                            warn!("User '{}' in show_link not found", user_name);
-                        }
-                    }
-                    info!("------------------------");
                 }
 
                 listeners.push(listener);
@@ -435,7 +627,103 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
         }
     }
 
-    if listeners.is_empty() {
+    // Show proxy links once when public_host is set, OR when there are no TCP listeners
+    // (unix-only mode) — use detected IP as fallback
+    if !config.general.links.show.is_empty() && (config.general.links.public_host.is_some() || listeners.is_empty()) {
+        let (host, port) = if let Some(ref h) = config.general.links.public_host {
+            (h.clone(), config.general.links.public_port.unwrap_or(config.server.port))
+        } else {
+            let ip = detected_ip_v4
+                .or(detected_ip_v6)
+                .map(|ip| ip.to_string());
+            if ip.is_none() {
+                warn!("show_link is configured but public IP could not be detected. Set public_host in config.");
+            }
+            (ip.unwrap_or_else(|| "UNKNOWN".to_string()), config.general.links.public_port.unwrap_or(config.server.port))
+        };
+
+        print_proxy_links(&host, port, &config);
+    }
+
+    // Unix socket setup (before listeners check so unix-only config works)
+    let mut has_unix_listener = false;
+    #[cfg(unix)]
+    if let Some(ref unix_path) = config.server.listen_unix_sock {
+        // Remove stale socket file if present (standard practice)
+        let _ = tokio::fs::remove_file(unix_path).await;
+
+        let unix_listener = UnixListener::bind(unix_path)?;
+
+        // Apply socket permissions if configured
+        if let Some(ref perm_str) = config.server.listen_unix_sock_perm {
+            match u32::from_str_radix(perm_str.trim_start_matches('0'), 8) {
+                Ok(mode) => {
+                    use std::os::unix::fs::PermissionsExt;
+                    let perms = std::fs::Permissions::from_mode(mode);
+                    if let Err(e) = std::fs::set_permissions(unix_path, perms) {
+                        error!("Failed to set unix socket permissions to {}: {}", perm_str, e);
+                    } else {
+                        info!("Listening on unix:{} (mode {})", unix_path, perm_str);
+                    }
+                }
+                Err(e) => {
+                    warn!("Invalid listen_unix_sock_perm '{}': {}. Ignoring.", perm_str, e);
+                    info!("Listening on unix:{}", unix_path);
+                }
+            }
+        } else {
+            info!("Listening on unix:{}", unix_path);
+        }
+
+        has_unix_listener = true;
+
+        let config = config.clone();
+        let stats = stats.clone();
+        let upstream_manager = upstream_manager.clone();
+        let replay_checker = replay_checker.clone();
+        let buffer_pool = buffer_pool.clone();
+        let rng = rng.clone();
+        let me_pool = me_pool.clone();
+        let ip_tracker = ip_tracker.clone();
+
+        tokio::spawn(async move {
+            let unix_conn_counter = std::sync::Arc::new(std::sync::atomic::AtomicU64::new(1));
+
+            loop {
+                match unix_listener.accept().await {
+                    Ok((stream, _)) => {
+                        let conn_id = unix_conn_counter.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+                        let fake_peer = SocketAddr::from(([127, 0, 0, 1], (conn_id % 65535) as u16));
+
+                        let config = config.clone();
+                        let stats = stats.clone();
+                        let upstream_manager = upstream_manager.clone();
+                        let replay_checker = replay_checker.clone();
+                        let buffer_pool = buffer_pool.clone();
+                        let rng = rng.clone();
+                        let me_pool = me_pool.clone();
+                        let ip_tracker = ip_tracker.clone();
+
+                        tokio::spawn(async move {
+                            if let Err(e) = crate::proxy::client::handle_client_stream(
+                                stream, fake_peer, config, stats,
+                                upstream_manager, replay_checker, buffer_pool, rng,
+                                me_pool, ip_tracker,
+                            ).await {
+                                debug!(error = %e, "Unix socket connection error");
+                            }
+                        });
+                    }
+                    Err(e) => {
+                        error!("Unix socket accept error: {}", e);
+                        tokio::time::sleep(Duration::from_millis(100)).await;
+                    }
+                }
+            }
+        });
+    }
+
+    if listeners.is_empty() && !has_unix_listener {
         error!("No listeners. Exiting.");
         std::process::exit(1);
     }
@@ -450,6 +738,14 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
         .reload(runtime_filter)
         .expect("Failed to switch log filter");
 
+    if let Some(port) = config.server.metrics_port {
+        let stats = stats.clone();
+        let whitelist = config.server.metrics_whitelist.clone();
+        tokio::spawn(async move {
+            metrics::serve(port, stats, whitelist).await;
+        });
+    }
+
     for listener in listeners {
         let config = config.clone();
         let stats = stats.clone();
@@ -458,6 +754,7 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
         let buffer_pool = buffer_pool.clone();
         let rng = rng.clone();
         let me_pool = me_pool.clone();
+        let ip_tracker = ip_tracker.clone();
 
         tokio::spawn(async move {
             loop {
@@ -470,6 +767,7 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
                         let buffer_pool = buffer_pool.clone();
                         let rng = rng.clone();
                         let me_pool = me_pool.clone();
+                        let ip_tracker = ip_tracker.clone();
 
                         tokio::spawn(async move {
                             if let Err(e) = ClientHandler::new(
@@ -482,6 +780,7 @@ async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
                                 buffer_pool,
                                 rng,
                                 me_pool,
+                                ip_tracker,
                             )
                             .run()
                             .await

src/metrics.rs

@@ -0,0 +1,197 @@
+use std::convert::Infallible;
+use std::net::{IpAddr, SocketAddr};
+use std::sync::Arc;
+
+use http_body_util::Full;
+use hyper::body::Bytes;
+use hyper::server::conn::http1;
+use hyper::service::service_fn;
+use hyper::{Request, Response, StatusCode};
+use tokio::net::TcpListener;
+use tracing::{info, warn, debug};
+
+use crate::stats::Stats;
+
+pub async fn serve(port: u16, stats: Arc<Stats>, whitelist: Vec<IpAddr>) {
+    let addr = SocketAddr::from(([0, 0, 0, 0], port));
+    let listener = match TcpListener::bind(addr).await {
+        Ok(l) => l,
+        Err(e) => {
+            warn!(error = %e, "Failed to bind metrics on {}", addr);
+            return;
+        }
+    };
+    info!("Metrics endpoint: http://{}/metrics", addr);
+
+    loop {
+        let (stream, peer) = match listener.accept().await {
+            Ok(v) => v,
+            Err(e) => {
+                warn!(error = %e, "Metrics accept error");
+                continue;
+            }
+        };
+
+        if !whitelist.is_empty() && !whitelist.contains(&peer.ip()) {
+            debug!(peer = %peer, "Metrics request denied by whitelist");
+            continue;
+        }
+
+        let stats = stats.clone();
+        tokio::spawn(async move {
+            let svc = service_fn(move |req| {
+                let stats = stats.clone();
+                async move { handle(req, &stats) }
+            });
+            if let Err(e) = http1::Builder::new()
+                .serve_connection(hyper_util::rt::TokioIo::new(stream), svc)
+                .await
+            {
+                debug!(error = %e, "Metrics connection error");
+            }
+        });
+    }
+}
+
+fn handle(req: Request<hyper::body::Incoming>, stats: &Stats) -> Result<Response<Full<Bytes>>, Infallible> {
+    if req.uri().path() != "/metrics" {
+        let resp = Response::builder()
+            .status(StatusCode::NOT_FOUND)
+            .body(Full::new(Bytes::from("Not Found\n")))
+            .unwrap();
+        return Ok(resp);
+    }
+
+    let body = render_metrics(stats);
+    let resp = Response::builder()
+        .status(StatusCode::OK)
+        .header("content-type", "text/plain; version=0.0.4; charset=utf-8")
+        .body(Full::new(Bytes::from(body)))
+        .unwrap();
+    Ok(resp)
+}
+
+fn render_metrics(stats: &Stats) -> String {
+    use std::fmt::Write;
+    let mut out = String::with_capacity(4096);
+
+    let _ = writeln!(out, "# HELP telemt_uptime_seconds Proxy uptime");
+    let _ = writeln!(out, "# TYPE telemt_uptime_seconds gauge");
+    let _ = writeln!(out, "telemt_uptime_seconds {:.1}", stats.uptime_secs());
+
+    let _ = writeln!(out, "# HELP telemt_connections_total Total accepted connections");
+    let _ = writeln!(out, "# TYPE telemt_connections_total counter");
+    let _ = writeln!(out, "telemt_connections_total {}", stats.get_connects_all());
+
+    let _ = writeln!(out, "# HELP telemt_connections_bad_total Bad/rejected connections");
+    let _ = writeln!(out, "# TYPE telemt_connections_bad_total counter");
+    let _ = writeln!(out, "telemt_connections_bad_total {}", stats.get_connects_bad());
+
+    let _ = writeln!(out, "# HELP telemt_handshake_timeouts_total Handshake timeouts");
+    let _ = writeln!(out, "# TYPE telemt_handshake_timeouts_total counter");
+    let _ = writeln!(out, "telemt_handshake_timeouts_total {}", stats.get_handshake_timeouts());
+
+    let _ = writeln!(out, "# HELP telemt_user_connections_total Per-user total connections");
+    let _ = writeln!(out, "# TYPE telemt_user_connections_total counter");
+    let _ = writeln!(out, "# HELP telemt_user_connections_current Per-user active connections");
+    let _ = writeln!(out, "# TYPE telemt_user_connections_current gauge");
+    let _ = writeln!(out, "# HELP telemt_user_octets_from_client Per-user bytes received");
+    let _ = writeln!(out, "# TYPE telemt_user_octets_from_client counter");
+    let _ = writeln!(out, "# HELP telemt_user_octets_to_client Per-user bytes sent");
+    let _ = writeln!(out, "# TYPE telemt_user_octets_to_client counter");
+    let _ = writeln!(out, "# HELP telemt_user_msgs_from_client Per-user messages received");
+    let _ = writeln!(out, "# TYPE telemt_user_msgs_from_client counter");
+    let _ = writeln!(out, "# HELP telemt_user_msgs_to_client Per-user messages sent");
+    let _ = writeln!(out, "# TYPE telemt_user_msgs_to_client counter");
+
+    for entry in stats.iter_user_stats() {
+        let user = entry.key();
+        let s = entry.value();
+        let _ = writeln!(out, "telemt_user_connections_total{{user=\"{}\"}} {}", user, s.connects.load(std::sync::atomic::Ordering::Relaxed));
+        let _ = writeln!(out, "telemt_user_connections_current{{user=\"{}\"}} {}", user, s.curr_connects.load(std::sync::atomic::Ordering::Relaxed));
+        let _ = writeln!(out, "telemt_user_octets_from_client{{user=\"{}\"}} {}", user, s.octets_from_client.load(std::sync::atomic::Ordering::Relaxed));
+        let _ = writeln!(out, "telemt_user_octets_to_client{{user=\"{}\"}} {}", user, s.octets_to_client.load(std::sync::atomic::Ordering::Relaxed));
+        let _ = writeln!(out, "telemt_user_msgs_from_client{{user=\"{}\"}} {}", user, s.msgs_from_client.load(std::sync::atomic::Ordering::Relaxed));
+        let _ = writeln!(out, "telemt_user_msgs_to_client{{user=\"{}\"}} {}", user, s.msgs_to_client.load(std::sync::atomic::Ordering::Relaxed));
+    }
+
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_render_metrics_format() {
+        let stats = Arc::new(Stats::new());
+        stats.increment_connects_all();
+        stats.increment_connects_all();
+        stats.increment_connects_bad();
+        stats.increment_handshake_timeouts();
+        stats.increment_user_connects("alice");
+        stats.increment_user_curr_connects("alice");
+        stats.add_user_octets_from("alice", 1024);
+        stats.add_user_octets_to("alice", 2048);
+        stats.increment_user_msgs_from("alice");
+        stats.increment_user_msgs_to("alice");
+        stats.increment_user_msgs_to("alice");
+
+        let output = render_metrics(&stats);
+
+        assert!(output.contains("telemt_connections_total 2"));
+        assert!(output.contains("telemt_connections_bad_total 1"));
+        assert!(output.contains("telemt_handshake_timeouts_total 1"));
+        assert!(output.contains("telemt_user_connections_total{user=\"alice\"} 1"));
+        assert!(output.contains("telemt_user_connections_current{user=\"alice\"} 1"));
+        assert!(output.contains("telemt_user_octets_from_client{user=\"alice\"} 1024"));
+        assert!(output.contains("telemt_user_octets_to_client{user=\"alice\"} 2048"));
+        assert!(output.contains("telemt_user_msgs_from_client{user=\"alice\"} 1"));
+        assert!(output.contains("telemt_user_msgs_to_client{user=\"alice\"} 2"));
+    }
+
+    #[test]
+    fn test_render_empty_stats() {
+        let stats = Stats::new();
+        let output = render_metrics(&stats);
+        assert!(output.contains("telemt_connections_total 0"));
+        assert!(output.contains("telemt_connections_bad_total 0"));
+        assert!(output.contains("telemt_handshake_timeouts_total 0"));
+        assert!(!output.contains("user="));
+    }
+
+    #[test]
+    fn test_render_has_type_annotations() {
+        let stats = Stats::new();
+        let output = render_metrics(&stats);
+        assert!(output.contains("# TYPE telemt_uptime_seconds gauge"));
+        assert!(output.contains("# TYPE telemt_connections_total counter"));
+        assert!(output.contains("# TYPE telemt_connections_bad_total counter"));
+        assert!(output.contains("# TYPE telemt_handshake_timeouts_total counter"));
+    }
+
+    #[tokio::test]
+    async fn test_endpoint_integration() {
+        let stats = Arc::new(Stats::new());
+        stats.increment_connects_all();
+        stats.increment_connects_all();
+        stats.increment_connects_all();
+
+        let port = 19091u16;
+        let s = stats.clone();
+        tokio::spawn(async move {
+            serve(port, s, vec![]).await;
+        });
+        tokio::time::sleep(std::time::Duration::from_millis(50)).await;
+
+        let resp = reqwest::get(format!("http://127.0.0.1:{}/metrics", port))
+            .await.unwrap();
+        assert_eq!(resp.status(), 200);
+        let body = resp.text().await.unwrap();
+        assert!(body.contains("telemt_connections_total 3"));
+
+        let resp404 = reqwest::get(format!("http://127.0.0.1:{}/other", port))
+            .await.unwrap();
+        assert_eq!(resp404.status(), 404);
+    }
+}

src/network/mod.rs

@@ -0,0 +1,4 @@
+pub mod probe;
+pub mod stun;
+
+pub use stun::IpFamily;

src/network/probe.rs

@@ -0,0 +1,225 @@
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, UdpSocket};
+
+use tracing::{info, warn};
+
+use crate::config::NetworkConfig;
+use crate::error::Result;
+use crate::network::stun::{stun_probe_dual, DualStunResult, IpFamily};
+
+#[derive(Debug, Clone, Default)]
+pub struct NetworkProbe {
+    pub detected_ipv4: Option<Ipv4Addr>,
+    pub detected_ipv6: Option<Ipv6Addr>,
+    pub reflected_ipv4: Option<SocketAddr>,
+    pub reflected_ipv6: Option<SocketAddr>,
+    pub ipv4_is_bogon: bool,
+    pub ipv6_is_bogon: bool,
+    pub ipv4_nat_detected: bool,
+    pub ipv6_nat_detected: bool,
+    pub ipv4_usable: bool,
+    pub ipv6_usable: bool,
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct NetworkDecision {
+    pub ipv4_dc: bool,
+    pub ipv6_dc: bool,
+    pub ipv4_me: bool,
+    pub ipv6_me: bool,
+    pub effective_prefer: u8,
+    pub effective_multipath: bool,
+}
+
+impl NetworkDecision {
+    pub fn prefer_ipv6(&self) -> bool {
+        self.effective_prefer == 6
+    }
+
+    pub fn me_families(&self) -> Vec<IpFamily> {
+        let mut res = Vec::new();
+        if self.ipv4_me {
+            res.push(IpFamily::V4);
+        }
+        if self.ipv6_me {
+            res.push(IpFamily::V6);
+        }
+        res
+    }
+}
+
+pub async fn run_probe(config: &NetworkConfig, stun_addr: Option<String>, nat_probe: bool) -> Result<NetworkProbe> {
+    let mut probe = NetworkProbe::default();
+
+    probe.detected_ipv4 = detect_local_ip_v4();
+    probe.detected_ipv6 = detect_local_ip_v6();
+
+    probe.ipv4_is_bogon = probe.detected_ipv4.map(is_bogon_v4).unwrap_or(false);
+    probe.ipv6_is_bogon = probe.detected_ipv6.map(is_bogon_v6).unwrap_or(false);
+
+    let stun_server = stun_addr.unwrap_or_else(|| "stun.l.google.com:19302".to_string());
+    let stun_res = if nat_probe {
+        stun_probe_dual(&stun_server).await?
+    } else {
+        DualStunResult::default()
+    };
+    probe.reflected_ipv4 = stun_res.v4.map(|r| r.reflected_addr);
+    probe.reflected_ipv6 = stun_res.v6.map(|r| r.reflected_addr);
+
+    probe.ipv4_nat_detected = match (probe.detected_ipv4, probe.reflected_ipv4) {
+        (Some(det), Some(reflected)) => det != reflected.ip(),
+        _ => false,
+    };
+    probe.ipv6_nat_detected = match (probe.detected_ipv6, probe.reflected_ipv6) {
+        (Some(det), Some(reflected)) => det != reflected.ip(),
+        _ => false,
+    };
+
+    probe.ipv4_usable = config.ipv4
+        && probe.detected_ipv4.is_some()
+        && (!probe.ipv4_is_bogon || probe.reflected_ipv4.map(|r| !is_bogon(r.ip())).unwrap_or(false));
+
+    let ipv6_enabled = config.ipv6.unwrap_or(probe.detected_ipv6.is_some());
+    probe.ipv6_usable = ipv6_enabled
+        && probe.detected_ipv6.is_some()
+        && (!probe.ipv6_is_bogon || probe.reflected_ipv6.map(|r| !is_bogon(r.ip())).unwrap_or(false));
+
+    Ok(probe)
+}
+
+pub fn decide_network_capabilities(config: &NetworkConfig, probe: &NetworkProbe) -> NetworkDecision {
+    let mut decision = NetworkDecision::default();
+
+    decision.ipv4_dc = config.ipv4 && probe.detected_ipv4.is_some();
+    decision.ipv6_dc = config.ipv6.unwrap_or(probe.detected_ipv6.is_some()) && probe.detected_ipv6.is_some();
+
+    decision.ipv4_me = config.ipv4
+        && probe.detected_ipv4.is_some()
+        && (!probe.ipv4_is_bogon || probe.reflected_ipv4.is_some());
+
+    let ipv6_enabled = config.ipv6.unwrap_or(probe.detected_ipv6.is_some());
+    decision.ipv6_me = ipv6_enabled
+        && probe.detected_ipv6.is_some()
+        && (!probe.ipv6_is_bogon || probe.reflected_ipv6.is_some());
+
+    decision.effective_prefer = match config.prefer {
+        6 if decision.ipv6_me || decision.ipv6_dc => 6,
+        4 if decision.ipv4_me || decision.ipv4_dc => 4,
+        6 => {
+            warn!("prefer=6 requested but IPv6 unavailable; falling back to IPv4");
+            4
+        }
+        _ => 4,
+    };
+
+    let me_families = decision.ipv4_me as u8 + decision.ipv6_me as u8;
+    decision.effective_multipath = config.multipath && me_families >= 2;
+
+    decision
+}
+
+fn detect_local_ip_v4() -> Option<Ipv4Addr> {
+    let socket = UdpSocket::bind("0.0.0.0:0").ok()?;
+    socket.connect("8.8.8.8:80").ok()?;
+    match socket.local_addr().ok()?.ip() {
+        IpAddr::V4(v4) => Some(v4),
+        _ => None,
+    }
+}
+
+fn detect_local_ip_v6() -> Option<Ipv6Addr> {
+    let socket = UdpSocket::bind("[::]:0").ok()?;
+    socket.connect("[2001:4860:4860::8888]:80").ok()?;
+    match socket.local_addr().ok()?.ip() {
+        IpAddr::V6(v6) => Some(v6),
+        _ => None,
+    }
+}
+
+pub fn is_bogon(ip: IpAddr) -> bool {
+    match ip {
+        IpAddr::V4(v4) => is_bogon_v4(v4),
+        IpAddr::V6(v6) => is_bogon_v6(v6),
+    }
+}
+
+pub fn is_bogon_v4(ip: Ipv4Addr) -> bool {
+    let octets = ip.octets();
+    if ip.is_private() || ip.is_loopback() || ip.is_link_local() {
+        return true;
+    }
+    if octets[0] == 0 {
+        return true;
+    }
+    if octets[0] == 100 && (octets[1] & 0xC0) == 64 {
+        return true;
+    }
+    if octets[0] == 192 && octets[1] == 0 && octets[2] == 0 {
+        return true;
+    }
+    if octets[0] == 192 && octets[1] == 0 && octets[2] == 2 {
+        return true;
+    }
+    if octets[0] == 198 && (octets[1] & 0xFE) == 18 {
+        return true;
+    }
+    if octets[0] == 198 && octets[1] == 51 && octets[2] == 100 {
+        return true;
+    }
+    if octets[0] == 203 && octets[1] == 0 && octets[2] == 113 {
+        return true;
+    }
+    if ip.is_multicast() {
+        return true;
+    }
+    if octets[0] >= 240 {
+        return true;
+    }
+    if ip.is_broadcast() {
+        return true;
+    }
+    false
+}
+
+pub fn is_bogon_v6(ip: Ipv6Addr) -> bool {
+    if ip.is_unspecified() || ip.is_loopback() || ip.is_unique_local() {
+        return true;
+    }
+    let segs = ip.segments();
+    if (segs[0] & 0xFFC0) == 0xFE80 {
+        return true;
+    }
+    if segs[0..5] == [0, 0, 0, 0, 0] && segs[5] == 0xFFFF {
+        return true;
+    }
+    if segs[0] == 0x0100 && segs[1..4] == [0, 0, 0] {
+        return true;
+    }
+    if segs[0] == 0x2001 && segs[1] == 0x0db8 {
+        return true;
+    }
+    if segs[0] == 0x2002 {
+        return true;
+    }
+    if ip.is_multicast() {
+        return true;
+    }
+    false
+}
+
+pub fn log_probe_result(probe: &NetworkProbe, decision: &NetworkDecision) {
+    info!(
+        ipv4 = probe.detected_ipv4.as_ref().map(|v| v.to_string()).unwrap_or_else(|| "-".into()),
+        ipv6 = probe.detected_ipv6.as_ref().map(|v| v.to_string()).unwrap_or_else(|| "-".into()),
+        reflected_v4 = probe.reflected_ipv4.as_ref().map(|v| v.ip().to_string()).unwrap_or_else(|| "-".into()),
+        reflected_v6 = probe.reflected_ipv6.as_ref().map(|v| v.ip().to_string()).unwrap_or_else(|| "-".into()),
+        ipv4_bogon = probe.ipv4_is_bogon,
+        ipv6_bogon = probe.ipv6_is_bogon,
+        ipv4_me = decision.ipv4_me,
+        ipv6_me = decision.ipv6_me,
+        ipv4_dc = decision.ipv4_dc,
+        ipv6_dc = decision.ipv6_dc,
+        prefer = decision.effective_prefer,
+        multipath = decision.effective_multipath,
+        "Network capabilities resolved"
+    );
+}

src/network/stun.rs

@@ -0,0 +1,186 @@
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
+
+use tokio::net::{lookup_host, UdpSocket};
+
+use crate::error::{ProxyError, Result};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum IpFamily {
+    V4,
+    V6,
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct StunProbeResult {
+    pub local_addr: SocketAddr,
+    pub reflected_addr: SocketAddr,
+    pub family: IpFamily,
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct DualStunResult {
+    pub v4: Option<StunProbeResult>,
+    pub v6: Option<StunProbeResult>,
+}
+
+pub async fn stun_probe_dual(stun_addr: &str) -> Result<DualStunResult> {
+    let (v4, v6) = tokio::join!(
+        stun_probe_family(stun_addr, IpFamily::V4),
+        stun_probe_family(stun_addr, IpFamily::V6),
+    );
+
+    Ok(DualStunResult {
+        v4: v4?,
+        v6: v6?,
+    })
+}
+
+pub async fn stun_probe_family(stun_addr: &str, family: IpFamily) -> Result<Option<StunProbeResult>> {
+    use rand::RngCore;
+
+    let bind_addr = match family {
+        IpFamily::V4 => "0.0.0.0:0",
+        IpFamily::V6 => "[::]:0",
+    };
+
+    let socket = UdpSocket::bind(bind_addr)
+        .await
+        .map_err(|e| ProxyError::Proxy(format!("STUN bind failed: {e}")))?;
+
+    let target_addr = resolve_stun_addr(stun_addr, family).await?;
+    if let Some(addr) = target_addr {
+        socket
+            .connect(addr)
+            .await
+            .map_err(|e| ProxyError::Proxy(format!("STUN connect failed: {e}")))?;
+    } else {
+        return Ok(None);
+    }
+
+    let mut req = [0u8; 20];
+    req[0..2].copy_from_slice(&0x0001u16.to_be_bytes()); // Binding Request
+    req[2..4].copy_from_slice(&0u16.to_be_bytes()); // length
+    req[4..8].copy_from_slice(&0x2112A442u32.to_be_bytes()); // magic cookie
+    rand::rng().fill_bytes(&mut req[8..20]); // transaction ID
+
+    socket
+        .send(&req)
+        .await
+        .map_err(|e| ProxyError::Proxy(format!("STUN send failed: {e}")))?;
+
+    let mut buf = [0u8; 256];
+    let n = socket
+        .recv(&mut buf)
+        .await
+        .map_err(|e| ProxyError::Proxy(format!("STUN recv failed: {e}")))?;
+    if n < 20 {
+        return Ok(None);
+    }
+
+    let magic = 0x2112A442u32.to_be_bytes();
+    let txid = &req[8..20];
+    let mut idx = 20;
+    while idx + 4 <= n {
+        let atype = u16::from_be_bytes(buf[idx..idx + 2].try_into().unwrap());
+        let alen = u16::from_be_bytes(buf[idx + 2..idx + 4].try_into().unwrap()) as usize;
+        idx += 4;
+        if idx + alen > n {
+            break;
+        }
+
+        match atype {
+            0x0020 /* XOR-MAPPED-ADDRESS */ | 0x0001 /* MAPPED-ADDRESS */ => {
+                if alen < 8 {
+                    break;
+                }
+                let family_byte = buf[idx + 1];
+                let port_bytes = [buf[idx + 2], buf[idx + 3]];
+                let len_check = match family_byte {
+                    0x01 => 4,
+                    0x02 => 16,
+                    _ => 0,
+                };
+                if len_check == 0 || alen < 4 + len_check {
+                    break;
+                }
+
+                let raw_ip = &buf[idx + 4..idx + 4 + len_check];
+                let mut port = u16::from_be_bytes(port_bytes);
+
+                let reflected_ip = if atype == 0x0020 {
+                    port ^= ((magic[0] as u16) << 8) | magic[1] as u16;
+                    match family_byte {
+                        0x01 => {
+                            let ip = [
+                                raw_ip[0] ^ magic[0],
+                                raw_ip[1] ^ magic[1],
+                                raw_ip[2] ^ magic[2],
+                                raw_ip[3] ^ magic[3],
+                            ];
+                            IpAddr::V4(Ipv4Addr::new(ip[0], ip[1], ip[2], ip[3]))
+                        }
+                        0x02 => {
+                            let mut ip = [0u8; 16];
+                            let xor_key = [magic.as_slice(), txid].concat();
+                            for (i, b) in raw_ip.iter().enumerate().take(16) {
+                                ip[i] = *b ^ xor_key[i];
+                            }
+                            IpAddr::V6(Ipv6Addr::from(ip))
+                        }
+                        _ => {
+                            idx += (alen + 3) & !3;
+                            continue;
+                        }
+                    }
+                } else {
+                    match family_byte {
+                        0x01 => IpAddr::V4(Ipv4Addr::new(raw_ip[0], raw_ip[1], raw_ip[2], raw_ip[3])),
+                        0x02 => IpAddr::V6(Ipv6Addr::from(<[u8; 16]>::try_from(raw_ip).unwrap())),
+                        _ => {
+                            idx += (alen + 3) & !3;
+                            continue;
+                        }
+                    }
+                };
+
+                let reflected_addr = SocketAddr::new(reflected_ip, port);
+                let local_addr = socket
+                    .local_addr()
+                    .map_err(|e| ProxyError::Proxy(format!("STUN local_addr failed: {e}")))?;
+
+                return Ok(Some(StunProbeResult {
+                    local_addr,
+                    reflected_addr,
+                    family,
+                }));
+            }
+            _ => {}
+        }
+
+        idx += (alen + 3) & !3;
+    }
+
+    Ok(None)
+}
+
+async fn resolve_stun_addr(stun_addr: &str, family: IpFamily) -> Result<Option<SocketAddr>> {
+    if let Ok(addr) = stun_addr.parse::<SocketAddr>() {
+        return Ok(match (addr.is_ipv4(), family) {
+            (true, IpFamily::V4) | (false, IpFamily::V6) => Some(addr),
+            _ => None,
+        });
+    }
+
+    let addrs = lookup_host(stun_addr)
+        .await
+        .map_err(|e| ProxyError::Proxy(format!("STUN resolve failed: {e}")))?;
+
+    let target = addrs
+        .filter(|a| match (a.is_ipv4(), family) {
+            (true, IpFamily::V4) => true,
+            (false, IpFamily::V6) => true,
+            _ => false,
+        })
+        .next();
+    Ok(target)
+}

src/protocol/obfuscation.rs

@@ -160,6 +160,12 @@ pub fn prepare_tg_nonce(
 }
 
 /// Encrypt the outgoing nonce for Telegram
+/// Legacy helper — **do not use**.
+/// WARNING: logic diverges from Python/C reference (SHA256 of 48 bytes, IV from head).
+/// Kept only to avoid breaking external callers; prefer `encrypt_tg_nonce_with_ciphers`.
+#[deprecated(
+    note = "Incorrect MTProto obfuscation KDF; use proxy::handshake::encrypt_tg_nonce_with_ciphers"
+)]
 pub fn encrypt_nonce(nonce: &[u8; HANDSHAKE_LEN]) -> Vec<u8> {
     let key_iv = &nonce[SKIP_LEN..SKIP_LEN + KEY_LEN + IV_LEN];
     let enc_key = sha256(key_iv);

src/protocol/tls.rs

@@ -8,6 +8,8 @@ use crate::crypto::{sha256_hmac, SecureRandom};
 use crate::error::{ProxyError, Result};
 use super::constants::*;
 use std::time::{SystemTime, UNIX_EPOCH};
+use num_bigint::BigUint;
+use num_traits::One;
 
 // ============= Public Constants =============
 
@@ -311,13 +313,27 @@ pub fn validate_tls_handshake(
     None
 }
 
+fn curve25519_prime() -> BigUint {
+    (BigUint::one() << 255) - BigUint::from(19u32)
+}
+
 /// Generate a fake X25519 public key for TLS
 ///
-/// This generates random bytes that look like a valid X25519 public key.
+/// Produces a quadratic residue mod p = 2^255 - 19 by computing n² mod p,
-/// Since we're not doing real TLS, the actual cryptographic properties don't matter.
+/// which matches Python/C behavior and avoids DPI fingerprinting.
 pub fn gen_fake_x25519_key(rng: &SecureRandom) -> [u8; 32] {
-    let bytes = rng.bytes(32);
+    let mut n_bytes = [0u8; 32];
-    bytes.try_into().unwrap()
+    n_bytes.copy_from_slice(&rng.bytes(32));
+
+    let n = BigUint::from_bytes_le(&n_bytes);
+    let p = curve25519_prime();
+    let pk = (&n * &n) % &p;
+
+    let mut out = pk.to_bytes_le();
+    out.resize(32, 0);
+    let mut result = [0u8; 32];
+    result.copy_from_slice(&out[..32]);
+    result
 }
 
 /// Build TLS ServerHello response
@@ -499,6 +515,17 @@ mod tests {
         assert_ne!(key1, key2); // Should be random
     }
 
+    #[test]
+    fn test_fake_x25519_key_is_quadratic_residue() {
+        let rng = SecureRandom::new();
+        let key = gen_fake_x25519_key(&rng);
+        let p = curve25519_prime();
+        let k_num = BigUint::from_bytes_le(&key);
+        let exponent = (&p - BigUint::one()) >> 1;
+        let legendre = k_num.modpow(&exponent, &p);
+        assert_eq!(legendre, BigUint::one());
+    }
+    
     #[test]
     fn test_tls_extension_builder() {
         let key = [0x42u8; 32];

src/proxy/client.rs

@@ -1,6 +1,8 @@
 //! Client Handler
 
+use std::future::Future;
 use std::net::SocketAddr;
+use std::pin::Pin;
 use std::sync::Arc;
 use std::time::Duration;
 use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite};
@@ -8,9 +10,21 @@ use tokio::net::TcpStream;
 use tokio::time::timeout;
 use tracing::{debug, warn};
 
+/// Post-handshake future (relay phase, runs outside handshake timeout)
+type PostHandshakeFuture = Pin<Box<dyn Future<Output = Result<()>> + Send>>;
+
+/// Result of the handshake phase
+enum HandshakeOutcome {
+    /// Handshake succeeded, relay work to do (outside timeout)
+    NeedsRelay(PostHandshakeFuture),
+    /// Already fully handled (bad client masking, etc.)
+    Handled,
+}
+
 use crate::config::ProxyConfig;
 use crate::crypto::SecureRandom;
 use crate::error::{HandshakeResult, ProxyError, Result};
+use crate::ip_tracker::UserIpTracker;
 use crate::protocol::constants::*;
 use crate::protocol::tls;
 use crate::stats::{ReplayChecker, Stats};
@@ -23,6 +37,160 @@ use crate::proxy::handshake::{HandshakeSuccess, handle_mtproto_handshake, handle
 use crate::proxy::masking::handle_bad_client;
 use crate::proxy::middle_relay::handle_via_middle_proxy;
 
+pub async fn handle_client_stream<S>(
+    mut stream: S,
+    peer: SocketAddr,
+    config: Arc<ProxyConfig>,
+    stats: Arc<Stats>,
+    upstream_manager: Arc<UpstreamManager>,
+    replay_checker: Arc<ReplayChecker>,
+    buffer_pool: Arc<BufferPool>,
+    rng: Arc<SecureRandom>,
+    me_pool: Option<Arc<MePool>>,
+    ip_tracker: Arc<UserIpTracker>,
+) -> Result<()>
+where
+    S: AsyncRead + AsyncWrite + Unpin + Send + 'static,
+{
+    stats.increment_connects_all();
+    debug!(peer = %peer, "New connection (generic stream)");
+
+    let handshake_timeout = Duration::from_secs(config.timeouts.client_handshake);
+    let stats_for_timeout = stats.clone();
+
+    // For non-TCP streams, use a synthetic local address
+    let local_addr: SocketAddr = format!("0.0.0.0:{}", config.server.port)
+        .parse()
+        .unwrap_or_else(|_| "0.0.0.0:443".parse().unwrap());
+
+    // Phase 1: handshake (with timeout)
+    let outcome = match timeout(handshake_timeout, async {
+        let mut first_bytes = [0u8; 5];
+        stream.read_exact(&mut first_bytes).await?;
+
+        let is_tls = tls::is_tls_handshake(&first_bytes[..3]);
+        debug!(peer = %peer, is_tls = is_tls, "Handshake type detected");
+
+        if is_tls {
+            let tls_len = u16::from_be_bytes([first_bytes[3], first_bytes[4]]) as usize;
+
+            if tls_len < 512 {
+                debug!(peer = %peer, tls_len = tls_len, "TLS handshake too short");
+                stats.increment_connects_bad();
+                let (reader, writer) = tokio::io::split(stream);
+                handle_bad_client(reader, writer, &first_bytes, &config).await;
+                return Ok(HandshakeOutcome::Handled);
+            }
+
+            let mut handshake = vec![0u8; 5 + tls_len];
+            handshake[..5].copy_from_slice(&first_bytes);
+            stream.read_exact(&mut handshake[5..]).await?;
+
+            let (read_half, write_half) = tokio::io::split(stream);
+
+            let (mut tls_reader, tls_writer, _tls_user) = match handle_tls_handshake(
+                &handshake, read_half, write_half, peer,
+                &config, &replay_checker, &rng,
+            ).await {
+                HandshakeResult::Success(result) => result,
+                HandshakeResult::BadClient { reader, writer } => {
+                    stats.increment_connects_bad();
+                    handle_bad_client(reader, writer, &handshake, &config).await;
+                    return Ok(HandshakeOutcome::Handled);
+                }
+                HandshakeResult::Error(e) => return Err(e),
+            };
+
+            debug!(peer = %peer, "Reading MTProto handshake through TLS");
+            let mtproto_data = tls_reader.read_exact(HANDSHAKE_LEN).await?;
+            let mtproto_handshake: [u8; HANDSHAKE_LEN] = mtproto_data[..].try_into()
+                .map_err(|_| ProxyError::InvalidHandshake("Short MTProto handshake".into()))?;
+
+            let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
+                &mtproto_handshake, tls_reader, tls_writer, peer,
+                &config, &replay_checker, true,
+            ).await {
+                HandshakeResult::Success(result) => result,
+                HandshakeResult::BadClient { reader: _, writer: _ } => {
+                    stats.increment_connects_bad();
+                    debug!(peer = %peer, "Valid TLS but invalid MTProto handshake");
+                    return Ok(HandshakeOutcome::Handled);
+                }
+                HandshakeResult::Error(e) => return Err(e),
+            };
+
+            Ok(HandshakeOutcome::NeedsRelay(Box::pin(
+                RunningClientHandler::handle_authenticated_static(
+                    crypto_reader, crypto_writer, success,
+                    upstream_manager, stats, config, buffer_pool, rng, me_pool,
+                    local_addr, peer, ip_tracker.clone(),
+                ),
+            )))
+        } else {
+            if !config.general.modes.classic && !config.general.modes.secure {
+                debug!(peer = %peer, "Non-TLS modes disabled");
+                stats.increment_connects_bad();
+                let (reader, writer) = tokio::io::split(stream);
+                handle_bad_client(reader, writer, &first_bytes, &config).await;
+                return Ok(HandshakeOutcome::Handled);
+            }
+
+            let mut handshake = [0u8; HANDSHAKE_LEN];
+            handshake[..5].copy_from_slice(&first_bytes);
+            stream.read_exact(&mut handshake[5..]).await?;
+
+            let (read_half, write_half) = tokio::io::split(stream);
+
+            let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
+                &handshake, read_half, write_half, peer,
+                &config, &replay_checker, false,
+            ).await {
+                HandshakeResult::Success(result) => result,
+                HandshakeResult::BadClient { reader, writer } => {
+                    stats.increment_connects_bad();
+                    handle_bad_client(reader, writer, &handshake, &config).await;
+                    return Ok(HandshakeOutcome::Handled);
+                }
+                HandshakeResult::Error(e) => return Err(e),
+            };
+
+            Ok(HandshakeOutcome::NeedsRelay(Box::pin(
+                RunningClientHandler::handle_authenticated_static(
+                    crypto_reader,
+                    crypto_writer,
+                    success,
+                    upstream_manager,
+                    stats,
+                    config,
+                    buffer_pool,
+                    rng,
+                    me_pool,
+                    local_addr,
+                    peer,
+                    ip_tracker.clone(),
+                )
+            )))
+        }
+    }).await {
+        Ok(Ok(outcome)) => outcome,
+        Ok(Err(e)) => {
+            debug!(peer = %peer, error = %e, "Handshake failed");
+            return Err(e);
+        }
+        Err(_) => {
+            stats_for_timeout.increment_handshake_timeouts();
+            debug!(peer = %peer, "Handshake timeout");
+            return Err(ProxyError::TgHandshakeTimeout);
+        }
+    };
+
+    // Phase 2: relay (WITHOUT handshake timeout — relay has its own activity timeouts)
+    match outcome {
+        HandshakeOutcome::NeedsRelay(fut) => fut.await,
+        HandshakeOutcome::Handled => Ok(()),
+    }
+}
+
 pub struct ClientHandler;
 
 pub struct RunningClientHandler {
@@ -35,6 +203,7 @@ pub struct RunningClientHandler {
     buffer_pool: Arc<BufferPool>,
     rng: Arc<SecureRandom>,
     me_pool: Option<Arc<MePool>>,
+    ip_tracker: Arc<UserIpTracker>,
 }
 
 impl ClientHandler {
@@ -48,6 +217,7 @@ impl ClientHandler {
         buffer_pool: Arc<BufferPool>,
         rng: Arc<SecureRandom>,
         me_pool: Option<Arc<MePool>>,
+        ip_tracker: Arc<UserIpTracker>,
     ) -> RunningClientHandler {
         RunningClientHandler {
             stream,
@@ -59,6 +229,7 @@ impl ClientHandler {
             buffer_pool,
             rng,
             me_pool,
+            ip_tracker,
         }
     }
 }
@@ -68,6 +239,7 @@ impl RunningClientHandler {
         self.stats.increment_connects_all();
 
         let peer = self.peer;
+        let ip_tracker = self.ip_tracker.clone();
         debug!(peer = %peer, "New connection");
 
         if let Err(e) = configure_client_socket(
@@ -81,31 +253,34 @@ impl RunningClientHandler {
         let handshake_timeout = Duration::from_secs(self.config.timeouts.client_handshake);
         let stats = self.stats.clone();
 
-        let result = timeout(handshake_timeout, self.do_handshake()).await;
+        // Phase 1: handshake (with timeout)
-
+        let outcome = match timeout(handshake_timeout, self.do_handshake()).await {
-        match result {
+            Ok(Ok(outcome)) => outcome,
-            Ok(Ok(())) => {
-                debug!(peer = %peer, "Connection handled successfully");
-                Ok(())
-            }
             Ok(Err(e)) => {
                 debug!(peer = %peer, error = %e, "Handshake failed");
-                Err(e)
+                return Err(e);
             }
             Err(_) => {
                 stats.increment_handshake_timeouts();
                 debug!(peer = %peer, "Handshake timeout");
-                Err(ProxyError::TgHandshakeTimeout)
+                return Err(ProxyError::TgHandshakeTimeout);
             }
+        };
+
+        // Phase 2: relay (WITHOUT handshake timeout — relay has its own activity timeouts)
+        match outcome {
+            HandshakeOutcome::NeedsRelay(fut) => fut.await,
+            HandshakeOutcome::Handled => Ok(()),
         }
     }
 
-    async fn do_handshake(mut self) -> Result<()> {
+    async fn do_handshake(mut self) -> Result<HandshakeOutcome> {
         let mut first_bytes = [0u8; 5];
         self.stream.read_exact(&mut first_bytes).await?;
 
         let is_tls = tls::is_tls_handshake(&first_bytes[..3]);
         let peer = self.peer;
+        let ip_tracker = self.ip_tracker.clone();
 
         debug!(peer = %peer, is_tls = is_tls, "Handshake type detected");
 
@@ -116,8 +291,9 @@ impl RunningClientHandler {
         }
     }
 
-    async fn handle_tls_client(mut self, first_bytes: [u8; 5]) -> Result<()> {
+    async fn handle_tls_client(mut self, first_bytes: [u8; 5]) -> Result<HandshakeOutcome> {
         let peer = self.peer;
+        let ip_tracker = self.ip_tracker.clone();
 
         let tls_len = u16::from_be_bytes([first_bytes[3], first_bytes[4]]) as usize;
 
@@ -128,7 +304,7 @@ impl RunningClientHandler {
             self.stats.increment_connects_bad();
             let (reader, writer) = self.stream.into_split();
             handle_bad_client(reader, writer, &first_bytes, &self.config).await;
-            return Ok(());
+            return Ok(HandshakeOutcome::Handled);
         }
 
         let mut handshake = vec![0u8; 5 + tls_len];
@@ -158,7 +334,7 @@ impl RunningClientHandler {
             HandshakeResult::BadClient { reader, writer } => {
                 stats.increment_connects_bad();
                 handle_bad_client(reader, writer, &handshake, &config).await;
-                return Ok(());
+                return Ok(HandshakeOutcome::Handled);
             }
             HandshakeResult::Error(e) => return Err(e),
         };
@@ -187,11 +363,12 @@ impl RunningClientHandler {
             } => {
                 stats.increment_connects_bad();
                 debug!(peer = %peer, "Valid TLS but invalid MTProto handshake");
-                return Ok(());
+                return Ok(HandshakeOutcome::Handled);
             }
             HandshakeResult::Error(e) => return Err(e),
         };
 
+        Ok(HandshakeOutcome::NeedsRelay(Box::pin(
             Self::handle_authenticated_static(
                 crypto_reader,
                 crypto_writer,
@@ -203,19 +380,22 @@ impl RunningClientHandler {
                 self.rng,
                 self.me_pool,
                 local_addr,
-        )
+                peer,
-        .await
+                self.ip_tracker,
+            ),
+        )))
     }
 
-    async fn handle_direct_client(mut self, first_bytes: [u8; 5]) -> Result<()> {
+    async fn handle_direct_client(mut self, first_bytes: [u8; 5]) -> Result<HandshakeOutcome> {
         let peer = self.peer;
+        let ip_tracker = self.ip_tracker.clone();
 
         if !self.config.general.modes.classic && !self.config.general.modes.secure {
             debug!(peer = %peer, "Non-TLS modes disabled");
             self.stats.increment_connects_bad();
             let (reader, writer) = self.stream.into_split();
             handle_bad_client(reader, writer, &first_bytes, &self.config).await;
-            return Ok(());
+            return Ok(HandshakeOutcome::Handled);
         }
 
         let mut handshake = [0u8; HANDSHAKE_LEN];
@@ -245,11 +425,12 @@ impl RunningClientHandler {
             HandshakeResult::BadClient { reader, writer } => {
                 stats.increment_connects_bad();
                 handle_bad_client(reader, writer, &handshake, &config).await;
-                return Ok(());
+                return Ok(HandshakeOutcome::Handled);
             }
             HandshakeResult::Error(e) => return Err(e),
         };
 
+        Ok(HandshakeOutcome::NeedsRelay(Box::pin(
             Self::handle_authenticated_static(
                 crypto_reader,
                 crypto_writer,
@@ -261,8 +442,10 @@ impl RunningClientHandler {
                 self.rng,
                 self.me_pool,
                 local_addr,
-        )
+                peer,
-        .await
+                self.ip_tracker,
+            ),
+        )))
     }
 
     /// Main dispatch after successful handshake.
@@ -280,6 +463,8 @@ impl RunningClientHandler {
         rng: Arc<SecureRandom>,
         me_pool: Option<Arc<MePool>>,
         local_addr: SocketAddr,
+        peer_addr: SocketAddr,
+        ip_tracker: Arc<UserIpTracker>,
     ) -> Result<()>
     where
         R: AsyncRead + Unpin + Send + 'static,
@@ -287,11 +472,36 @@ impl RunningClientHandler {
     {
         let user = &success.user;
 
-        if let Err(e) = Self::check_user_limits_static(user, &config, &stats) {
+        if let Err(e) = Self::check_user_limits_static(user, &config, &stats, peer_addr, &ip_tracker).await {
             warn!(user = %user, error = %e, "User limit exceeded");
             return Err(e);
         }
 
+        // IP Cleanup Guard: автоматически удаляет IP при выходе из scope
+        struct IpCleanupGuard {
+            tracker: Arc<UserIpTracker>,
+            user: String,
+            ip: std::net::IpAddr,
+        }
+        
+        impl Drop for IpCleanupGuard {
+            fn drop(&mut self) {
+                let tracker = self.tracker.clone();
+                let user = self.user.clone();
+                let ip = self.ip;
+                tokio::spawn(async move {
+                    tracker.remove_ip(&user, ip).await;
+                    debug!(user = %user, ip = %ip, "IP cleaned up on disconnect");
+                });
+            }
+        }
+        
+        let _cleanup = IpCleanupGuard {
+            tracker: ip_tracker,
+            user: user.clone(),
+            ip: peer_addr.ip(),
+        };
+
         // Decide: middle proxy or direct
         if config.general.use_middle_proxy {
             if let Some(ref pool) = me_pool {
@@ -304,6 +514,7 @@ impl RunningClientHandler {
                     config,
                     buffer_pool,
                     local_addr,
+                    rng,
                 )
                 .await;
             }
@@ -324,7 +535,13 @@ impl RunningClientHandler {
         .await
     }
 
-    fn check_user_limits_static(user: &str, config: &ProxyConfig, stats: &Stats) -> Result<()> {
+    async fn check_user_limits_static(
+        user: &str, 
+        config: &ProxyConfig, 
+        stats: &Stats,
+        peer_addr: SocketAddr,
+        ip_tracker: &UserIpTracker,
+    ) -> Result<()> {
         if let Some(expiration) = config.access.user_expirations.get(user) {
             if chrono::Utc::now() > *expiration {
                 return Err(ProxyError::UserExpired {
@@ -333,6 +550,19 @@ impl RunningClientHandler {
             }
         }
 
+        // IP limit check
+        if let Err(reason) = ip_tracker.check_and_add(user, peer_addr.ip()).await {
+            warn!(
+                user = %user, 
+                ip = %peer_addr.ip(),
+                reason = %reason,
+                "IP limit exceeded"
+            );
+            return Err(ProxyError::ConnectionLimitExceeded {
+                user: user.to_string(),
+            });
+        }
+
         if let Some(limit) = config.access.user_max_tcp_conns.get(user) {
             if stats.get_user_curr_connects(user) >= *limit as u64 {
                 return Err(ProxyError::ConnectionLimitExceeded {

src/proxy/direct_relay.rs

@@ -1,3 +1,5 @@
+use std::fs::OpenOptions;
+use std::io::Write;
 use std::net::SocketAddr;
 use std::sync::Arc;
 
@@ -78,7 +80,8 @@ where
 }
 
 fn get_dc_addr_static(dc_idx: i16, config: &ProxyConfig) -> Result<SocketAddr> {
-    let datacenters = if config.general.prefer_ipv6 {
+    let prefer_v6 = config.network.prefer == 6 && config.network.ipv6.unwrap_or(true);
+    let datacenters = if prefer_v6 {
         &*TG_DATACENTERS_V6
     } else {
         &*TG_DATACENTERS_V4
@@ -87,17 +90,24 @@ fn get_dc_addr_static(dc_idx: i16, config: &ProxyConfig) -> Result<SocketAddr> {
     let num_dcs = datacenters.len();
 
     let dc_key = dc_idx.to_string();
-    if let Some(addr_str) = config.dc_overrides.get(&dc_key) {
+    if let Some(addrs) = config.dc_overrides.get(&dc_key) {
+        let mut parsed = Vec::new();
+        for addr_str in addrs {
             match addr_str.parse::<SocketAddr>() {
-            Ok(addr) => {
+                Ok(addr) => parsed.push(addr),
-                debug!(dc_idx = dc_idx, addr = %addr, "Using DC override from config");
+                Err(_) => warn!(dc_idx = dc_idx, addr_str = %addr_str, "Invalid DC override address in config, ignoring"),
+            }
+        }
+
+        if let Some(addr) = parsed
+            .iter()
+            .find(|a| a.is_ipv6() == prefer_v6)
+            .or_else(|| parsed.first())
+            .copied()
+        {
+            debug!(dc_idx = dc_idx, addr = %addr, count = parsed.len(), "Using DC override from config");
             return Ok(addr);
         }
-            Err(_) => {
-                warn!(dc_idx = dc_idx, addr_str = %addr_str,
-                        "Invalid DC override address in config, ignoring");
-            }
-        }
     }
 
     let abs_dc = dc_idx.unsigned_abs() as usize;
@@ -105,6 +115,16 @@ fn get_dc_addr_static(dc_idx: i16, config: &ProxyConfig) -> Result<SocketAddr> {
         return Ok(SocketAddr::new(datacenters[abs_dc - 1], TG_DATACENTER_PORT));
     }
 
+    // Unknown DC requested by client without override: log and fall back.
+    if !config.dc_overrides.contains_key(&dc_key) {
+        warn!(dc_idx = dc_idx, "Requested non-standard DC with no override; falling back to default cluster");
+        if let Some(path) = &config.general.unknown_dc_log_path {
+            if let Ok(mut file) = OpenOptions::new().create(true).append(true).open(path) {
+                let _ = writeln!(file, "dc_idx={dc_idx}");
+            }
+        }
+    }
+
     let default_dc = config.default_dc.unwrap_or(2) as usize;
     let fallback_idx = if default_dc >= 1 && default_dc <= num_dcs {
         default_dc - 1
@@ -139,6 +159,8 @@ async fn do_tg_handshake_static(
         success.dc_idx,
         &success.dec_key,
         success.dec_iv,
+        &success.enc_key,
+        success.enc_iv,
         rng,
         config.general.fast_mode,
     );

src/proxy/handshake.rs

@@ -70,7 +70,7 @@ where
     let digest = &handshake[tls::TLS_DIGEST_POS..tls::TLS_DIGEST_POS + tls::TLS_DIGEST_LEN];
     let digest_half = &digest[..tls::TLS_DIGEST_HALF_LEN];
 
-    if replay_checker.check_tls_digest(digest_half) {
+    if replay_checker.check_and_add_tls_digest(digest_half) {
         warn!(peer = %peer, "TLS replay attack detected (duplicate digest)");
         return HandshakeResult::BadClient { reader, writer };
     }
@@ -122,8 +122,6 @@ where
         return HandshakeResult::Error(ProxyError::Io(e));
     }
 
-    replay_checker.add_tls_digest(digest_half);
-
     info!(
         peer = %peer,
         user = %validation.user,
@@ -155,7 +153,7 @@ where
 
     let dec_prekey_iv = &handshake[SKIP_LEN..SKIP_LEN + PREKEY_LEN + IV_LEN];
 
-    if replay_checker.check_handshake(dec_prekey_iv) {
+    if replay_checker.check_and_add_handshake(dec_prekey_iv) {
         warn!(peer = %peer, "MTProto replay attack detected");
         return HandshakeResult::BadClient { reader, writer };
     }
@@ -216,8 +214,6 @@ where
 
         let enc_iv = u128::from_be_bytes(enc_iv_bytes.try_into().unwrap());
 
-        replay_checker.add_handshake(dec_prekey_iv);
-
         let encryptor = AesCtr::new(&enc_key, enc_iv);
 
         let success = HandshakeSuccess {
@@ -256,8 +252,10 @@ where
 pub fn generate_tg_nonce(
     proto_tag: ProtoTag, 
     dc_idx: i16,
-    client_dec_key: &[u8; 32],
+    _client_dec_key: &[u8; 32],
-    client_dec_iv: u128,
+    _client_dec_iv: u128,
+    client_enc_key: &[u8; 32],
+    client_enc_iv: u128,
     rng: &SecureRandom,
     fast_mode: bool,
 ) -> ([u8; HANDSHAKE_LEN], [u8; 32], u128, [u8; 32], u128) {
@@ -278,9 +276,11 @@ pub fn generate_tg_nonce(
         nonce[DC_IDX_POS..DC_IDX_POS + 2].copy_from_slice(&dc_idx.to_le_bytes());
 
         if fast_mode {
-            nonce[SKIP_LEN..SKIP_LEN + KEY_LEN].copy_from_slice(client_dec_key);
+            let mut key_iv = Vec::with_capacity(KEY_LEN + IV_LEN);
-            nonce[SKIP_LEN + KEY_LEN..SKIP_LEN + KEY_LEN + IV_LEN]
+            key_iv.extend_from_slice(client_enc_key);
-                .copy_from_slice(&client_dec_iv.to_be_bytes());
+            key_iv.extend_from_slice(&client_enc_iv.to_be_bytes());
+            key_iv.reverse(); // Python/C behavior: reversed enc_key+enc_iv in nonce
+            nonce[SKIP_LEN..SKIP_LEN + KEY_LEN + IV_LEN].copy_from_slice(&key_iv);
         }
 
         let enc_key_iv = &nonce[SKIP_LEN..SKIP_LEN + KEY_LEN + IV_LEN];
@@ -332,10 +332,21 @@ mod tests {
     fn test_generate_tg_nonce() {
         let client_dec_key = [0x42u8; 32];
         let client_dec_iv = 12345u128;
+        let client_enc_key = [0x24u8; 32];
+        let client_enc_iv = 54321u128;
 
         let rng = SecureRandom::new();
         let (nonce, _tg_enc_key, _tg_enc_iv, _tg_dec_key, _tg_dec_iv) = 
-            generate_tg_nonce(ProtoTag::Secure, 2, &client_dec_key, client_dec_iv, &rng, false);
+            generate_tg_nonce(
+                ProtoTag::Secure,
+                2,
+                &client_dec_key,
+                client_dec_iv,
+                &client_enc_key,
+                client_enc_iv,
+                &rng,
+                false,
+            );
 
         assert_eq!(nonce.len(), HANDSHAKE_LEN);
 
@@ -347,10 +358,21 @@ mod tests {
     fn test_encrypt_tg_nonce() {
         let client_dec_key = [0x42u8; 32];
         let client_dec_iv = 12345u128;
+        let client_enc_key = [0x24u8; 32];
+        let client_enc_iv = 54321u128;
 
         let rng = SecureRandom::new();
         let (nonce, _, _, _, _) = 
-            generate_tg_nonce(ProtoTag::Secure, 2, &client_dec_key, client_dec_iv, &rng, false);
+            generate_tg_nonce(
+                ProtoTag::Secure,
+                2,
+                &client_dec_key,
+                client_dec_iv,
+                &client_enc_key,
+                client_enc_iv,
+                &rng,
+                false,
+            );
 
         let encrypted = encrypt_tg_nonce(&nonce);
 

src/proxy/middle_relay.rs

@@ -5,6 +5,7 @@ use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
 use tracing::{debug, info, trace};
 
 use crate::config::ProxyConfig;
+use crate::crypto::SecureRandom;
 use crate::error::{ProxyError, Result};
 use crate::protocol::constants::*;
 use crate::proxy::handshake::HandshakeSuccess;
@@ -21,6 +22,7 @@ pub(crate) async fn handle_via_middle_proxy<R, W>(
     _config: Arc<ProxyConfig>,
     _buffer_pool: Arc<BufferPool>,
     local_addr: SocketAddr,
+    rng: Arc<SecureRandom>,
 ) -> Result<()>
 where
     R: AsyncRead + Unpin + Send + 'static,
@@ -58,16 +60,23 @@ where
         tokio::select! {
             client_frame = read_client_payload(&mut crypto_reader, proto_tag) => {
                 match client_frame {
-                    Ok(Some(payload)) => {
+                    Ok(Some((payload, quickack))) => {
                         trace!(conn_id, bytes = payload.len(), "C->ME frame");
                         stats.add_user_octets_from(&user, payload.len() as u64);
+                        let mut flags = proto_flags;
+                        if quickack {
+                            flags |= RPC_FLAG_QUICKACK;
+                        }
+                        if payload.len() >= 8 && payload[..8].iter().all(|b| *b == 0) {
+                            flags |= RPC_FLAG_NOT_ENCRYPTED;
+                        }
                         me_pool.send_proxy_req(
                             conn_id,
                             success.dc_idx,
                             peer,
                             translated_local_addr,
                             &payload,
-                            proto_flags,
+                            flags,
                         ).await?;
                     }
                     Ok(None) => {
@@ -83,7 +92,7 @@ where
                     Some(MeResponse::Data { flags, data }) => {
                         trace!(conn_id, bytes = data.len(), flags, "ME->C data");
                         stats.add_user_octets_to(&user, data.len() as u64);
-                        write_client_payload(&mut crypto_writer, proto_tag, flags, &data).await?;
+                        write_client_payload(&mut crypto_writer, proto_tag, flags, &data, rng.as_ref()).await?;
                     }
                     Some(MeResponse::Ack(confirm)) => {
                         trace!(conn_id, confirm, "ME->C quickack");
@@ -111,11 +120,11 @@ where
 async fn read_client_payload<R>(
     client_reader: &mut CryptoReader<R>,
     proto_tag: ProtoTag,
-) -> Result<Option<Vec<u8>>>
+) -> Result<Option<(Vec<u8>, bool)>>
 where
     R: AsyncRead + Unpin + Send + 'static,
 {
-    let len = match proto_tag {
+    let (len, quickack) = match proto_tag {
         ProtoTag::Abridged => {
             let mut first = [0u8; 1];
             match client_reader.read_exact(&mut first).await {
@@ -124,6 +133,7 @@ where
                 Err(e) => return Err(ProxyError::Io(e)),
             }
 
+            let quickack = (first[0] & 0x80) != 0;
             let len_words = if (first[0] & 0x7f) == 0x7f {
                 let mut ext = [0u8; 3];
                 client_reader
@@ -135,9 +145,10 @@ where
                 (first[0] & 0x7f) as usize
             };
 
-            len_words
+            let len = len_words
                 .checked_mul(4)
-                .ok_or_else(|| ProxyError::Proxy("Abridged frame length overflow".into()))?
+                .ok_or_else(|| ProxyError::Proxy("Abridged frame length overflow".into()))?;
+            (len, quickack)
         }
         ProtoTag::Intermediate | ProtoTag::Secure => {
             let mut len_buf = [0u8; 4];
@@ -146,7 +157,8 @@ where
                 Err(e) if e.kind() == std::io::ErrorKind::UnexpectedEof => return Ok(None),
                 Err(e) => return Err(ProxyError::Io(e)),
             }
-            (u32::from_le_bytes(len_buf) & 0x7fff_ffff) as usize
+            let quickack = (len_buf[3] & 0x80) != 0;
+            ((u32::from_le_bytes(len_buf) & 0x7fff_ffff) as usize, quickack)
         }
     };
 
@@ -159,7 +171,15 @@ where
         .read_exact(&mut payload)
         .await
         .map_err(ProxyError::Io)?;
-    Ok(Some(payload))
+
+    // Secure Intermediate: remove random padding (last len%4 bytes)
+    if proto_tag == ProtoTag::Secure {
+        let rem = len % 4;
+        if rem != 0 && payload.len() >= rem {
+            payload.truncate(len - rem);
+        }
+    }
+    Ok(Some((payload, quickack)))
 }
 
 async fn write_client_payload<W>(
@@ -167,6 +187,7 @@ async fn write_client_payload<W>(
     proto_tag: ProtoTag,
     flags: u32,
     data: &[u8],
+    rng: &SecureRandom,
 ) -> Result<()>
 where
     W: AsyncWrite + Unpin + Send + 'static,
@@ -215,7 +236,12 @@ where
                 .map_err(ProxyError::Io)?;
         }
         ProtoTag::Intermediate | ProtoTag::Secure => {
-            let mut len = data.len() as u32;
+            let padding_len = if proto_tag == ProtoTag::Secure {
+                (rng.bytes(1)[0] % 4) as usize
+            } else {
+                0
+            };
+            let mut len = (data.len() + padding_len) as u32;
             if quickack {
                 len |= 0x8000_0000;
             }
@@ -227,10 +253,24 @@ where
                 .write_all(data)
                 .await
                 .map_err(ProxyError::Io)?;
+            if padding_len > 0 {
+                let pad = rng.bytes(padding_len);
+                client_writer
+                    .write_all(&pad)
+                    .await
+                    .map_err(ProxyError::Io)?;
+            }
         }
     }
 
-    client_writer.flush().await.map_err(ProxyError::Io)
+    // Avoid unconditional per-frame flush (throughput killer on large downloads).
+    // Flush only when low-latency ack semantics are requested or when
+    // CryptoWriter has buffered pending ciphertext that must be drained.
+    if quickack || client_writer.has_pending() {
+        client_writer.flush().await.map_err(ProxyError::Io)?;
+    }
+
+    Ok(())
 }
 
 async fn write_client_ack<W>(
@@ -250,5 +290,6 @@ where
         .write_all(&bytes)
         .await
         .map_err(ProxyError::Io)?;
+    // ACK should remain low-latency.
     client_writer.flush().await.map_err(ProxyError::Io)
 }

src/stats/mod.rs

@@ -97,6 +97,12 @@ impl Stats {
             .unwrap_or(0)
     }
     
+    pub fn get_handshake_timeouts(&self) -> u64 { self.handshake_timeouts.load(Ordering::Relaxed) }
+
+    pub fn iter_user_stats(&self) -> dashmap::iter::Iter<'_, String, UserStats> {
+        self.user_stats.iter()
+    }
+
     pub fn uptime_secs(&self) -> f64 {
         self.start_time.read()
             .map(|t| t.elapsed().as_secs_f64())
@@ -212,28 +218,41 @@ impl ReplayChecker {
         (hasher.finish() as usize) & self.shard_mask
     }
 
-    fn check(&self, data: &[u8]) -> bool {
+    fn check_and_add_internal(&self, data: &[u8]) -> bool {
         self.checks.fetch_add(1, Ordering::Relaxed);
         let idx = self.get_shard_idx(data);
         let mut shard = self.shards[idx].lock();
-        let found = shard.check(data, Instant::now(), self.window);
+        let now = Instant::now();
+        let found = shard.check(data, now, self.window);
         if found {
             self.hits.fetch_add(1, Ordering::Relaxed);
+        } else {
+            shard.add(data, now, self.window);
+            self.additions.fetch_add(1, Ordering::Relaxed);
         }
         found
     }
 
-    fn add(&self, data: &[u8]) {
+    fn add_only(&self, data: &[u8]) {
         self.additions.fetch_add(1, Ordering::Relaxed);
         let idx = self.get_shard_idx(data);
         let mut shard = self.shards[idx].lock();
         shard.add(data, Instant::now(), self.window);
     }
 
-    pub fn check_handshake(&self, data: &[u8]) -> bool { self.check(data) }
+    pub fn check_and_add_handshake(&self, data: &[u8]) -> bool {
-    pub fn add_handshake(&self, data: &[u8]) { self.add(data) }
+        self.check_and_add_internal(data)
-    pub fn check_tls_digest(&self, data: &[u8]) -> bool { self.check(data) }
+    }
-    pub fn add_tls_digest(&self, data: &[u8]) { self.add(data) }
+
+    pub fn check_and_add_tls_digest(&self, data: &[u8]) -> bool {
+        self.check_and_add_internal(data)
+    }
+
+    // Compatibility helpers (non-atomic split operations) — prefer check_and_add_*.
+    pub fn check_handshake(&self, data: &[u8]) -> bool { self.check_and_add_handshake(data) }
+    pub fn add_handshake(&self, data: &[u8]) { self.add_only(data) }
+    pub fn check_tls_digest(&self, data: &[u8]) -> bool { self.check_and_add_tls_digest(data) }
+    pub fn add_tls_digest(&self, data: &[u8]) { self.add_only(data) }
     
     pub fn stats(&self) -> ReplayStats {
         let mut total_entries = 0;
@@ -326,10 +345,9 @@ mod tests {
     #[test]
     fn test_replay_checker_basic() {
         let checker = ReplayChecker::new(100, Duration::from_secs(60));
-        assert!(!checker.check_handshake(b"test1"));
+        assert!(!checker.check_handshake(b"test1")); // first time, inserts
-        checker.add_handshake(b"test1");
+        assert!(checker.check_handshake(b"test1"));  // duplicate
-        assert!(checker.check_handshake(b"test1"));
+        assert!(!checker.check_handshake(b"test2")); // new key inserts
-        assert!(!checker.check_handshake(b"test2"));
     }
     
     #[test]
@@ -343,7 +361,7 @@ mod tests {
     #[test]
     fn test_replay_checker_expiration() {
         let checker = ReplayChecker::new(100, Duration::from_millis(50));
-        checker.add_handshake(b"expire");
+        assert!(!checker.check_handshake(b"expire"));
         assert!(checker.check_handshake(b"expire"));
         std::thread::sleep(Duration::from_millis(100));
         assert!(!checker.check_handshake(b"expire"));
@@ -352,24 +370,24 @@ mod tests {
     #[test]
     fn test_replay_checker_stats() {
         let checker = ReplayChecker::new(100, Duration::from_secs(60));
-        checker.add_handshake(b"k1");
+        assert!(!checker.check_handshake(b"k1"));
-        checker.add_handshake(b"k2");
+        assert!(!checker.check_handshake(b"k2"));
-        checker.check_handshake(b"k1");
+        assert!(checker.check_handshake(b"k1"));
-        checker.check_handshake(b"k3");
+        assert!(!checker.check_handshake(b"k3"));
         let stats = checker.stats();
-        assert_eq!(stats.total_additions, 2);
+        assert_eq!(stats.total_additions, 3);
-        assert_eq!(stats.total_checks, 2);
+        assert_eq!(stats.total_checks, 4);
         assert_eq!(stats.total_hits, 1);
     }
     
     #[test]
     fn test_replay_checker_many_keys() {
-        let checker = ReplayChecker::new(1000, Duration::from_secs(60));
+        let checker = ReplayChecker::new(10_000, Duration::from_secs(60));
         for i in 0..500u32 {
-            checker.add(&i.to_le_bytes());
+            checker.add_only(&i.to_le_bytes());
         }
         for i in 0..500u32 {
-            assert!(checker.check(&i.to_le_bytes()));
+            assert!(checker.check_handshake(&i.to_le_bytes()));
         }
         assert_eq!(checker.stats().total_entries, 500);
     }

src/stream/buffer_pool.rs

@@ -381,9 +381,14 @@ mod tests {
         // Add a buffer to pool
         pool.preallocate(1);
         
-        // Now try_get should succeed
+        // Now try_get should succeed once while the buffer is held
-        assert!(pool.try_get().is_some());
+        let buf = pool.try_get();
+        assert!(buf.is_some());
+        // While buffer is held, pool is empty
         assert!(pool.try_get().is_none());
+        // Drop buffer -> returns to pool, should be obtainable again
+        drop(buf);
+        assert!(pool.try_get().is_some());
     }
     
     #[test]

src/stream/tls_stream.rs

@@ -32,7 +32,7 @@
 //! and uploads from iOS will break (media/file sending), while small traffic
 //! may still work.
 
-use bytes::{Bytes, BytesMut, BufMut};
+use bytes::{Bytes, BytesMut};
 use std::io::{self, Error, ErrorKind, Result};
 use std::pin::Pin;
 use std::task::{Context, Poll};
@@ -51,9 +51,10 @@ use super::state::{StreamState, HeaderBuffer, YieldBuffer, WriteBuffer};
 /// TLS record header size (type + version + length)
 const TLS_HEADER_SIZE: usize = 5;
 
-/// Maximum TLS fragment size per spec (plaintext fragment).
+/// Maximum TLS fragment size we emit for Application Data.
-/// We use this for *outgoing* chunking, because we build plain ApplicationData records.
+/// Real TLS 1.3 ciphertexts often add ~16-24 bytes AEAD overhead, so to mimic
-const MAX_TLS_PAYLOAD: usize = 16384;
+/// on-the-wire record sizes we allow up to 16384 + 24 bytes of plaintext.
+const MAX_TLS_PAYLOAD: usize = 16384 + 24;
 
 /// Maximum pending write buffer for one record remainder.
 /// Note: we never queue unlimited amount of data here; state holds at most one record.
@@ -918,10 +919,8 @@ mod tests {
         let reader = ChunkedReader::new(&record, 100);
         let mut tls_reader = FakeTlsReader::new(reader);
         
-        let mut buf = vec![0u8; payload.len()];
+        let buf = tls_reader.read_exact(payload.len()).await.unwrap();
-        tls_reader.read_exact(&mut buf).await.unwrap();
+        assert_eq!(&buf[..], payload);
-        
-        assert_eq!(&buf, payload);
     }
     
     #[tokio::test]
@@ -935,13 +934,11 @@ mod tests {
         let reader = ChunkedReader::new(&data, 100);
         let mut tls_reader = FakeTlsReader::new(reader);
         
-        let mut buf1 = vec![0u8; payload1.len()];
+        let buf1 = tls_reader.read_exact(payload1.len()).await.unwrap();
-        tls_reader.read_exact(&mut buf1).await.unwrap();
+        assert_eq!(&buf1[..], payload1);
-        assert_eq!(&buf1, payload1);
         
-        let mut buf2 = vec![0u8; payload2.len()];
+        let buf2 = tls_reader.read_exact(payload2.len()).await.unwrap();
-        tls_reader.read_exact(&mut buf2).await.unwrap();
+        assert_eq!(&buf2[..], payload2);
-        assert_eq!(&buf2, payload2);
     }
     
     #[tokio::test]
@@ -953,10 +950,9 @@ mod tests {
         let reader = ChunkedReader::new(&record, 1); // 1 byte at a time!
         let mut tls_reader = FakeTlsReader::new(reader);
         
-        let mut buf = vec![0u8; payload.len()];
+        let buf = tls_reader.read_exact(payload.len()).await.unwrap();
-        tls_reader.read_exact(&mut buf).await.unwrap();
         
-        assert_eq!(&buf, payload);
+        assert_eq!(&buf[..], payload);
     }
     
     #[tokio::test]
@@ -967,10 +963,9 @@ mod tests {
         let reader = ChunkedReader::new(&record, 7); // Awkward chunk size
         let mut tls_reader = FakeTlsReader::new(reader);
         
-        let mut buf = vec![0u8; payload.len()];
+        let buf = tls_reader.read_exact(payload.len()).await.unwrap();
-        tls_reader.read_exact(&mut buf).await.unwrap();
         
-        assert_eq!(&buf, payload);
+        assert_eq!(&buf[..], payload);
     }
     
     #[tokio::test]
@@ -983,10 +978,9 @@ mod tests {
         let reader = ChunkedReader::new(&data, 100);
         let mut tls_reader = FakeTlsReader::new(reader);
         
-        let mut buf = vec![0u8; payload.len()];
+        let buf = tls_reader.read_exact(payload.len()).await.unwrap();
-        tls_reader.read_exact(&mut buf).await.unwrap();
         
-        assert_eq!(&buf, payload);
+        assert_eq!(&buf[..], payload);
     }
     
     #[tokio::test]
@@ -1000,10 +994,9 @@ mod tests {
         let reader = ChunkedReader::new(&data, 3); // Small chunks
         let mut tls_reader = FakeTlsReader::new(reader);
         
-        let mut buf = vec![0u8; payload.len()];
+        let buf = tls_reader.read_exact(payload.len()).await.unwrap();
-        tls_reader.read_exact(&mut buf).await.unwrap();
         
-        assert_eq!(&buf, payload);
+        assert_eq!(&buf[..], payload);
     }
     
     #[tokio::test]

src/transport/middle_proxy.rs

@@ -1,925 +0,0 @@
-//! Middle Proxy RPC Transport
-//!
-//! Implements Telegram Middle-End RPC protocol for routing to ALL DCs (including CDN).
-//!
-//! ## Phase 3 fixes:
-//! - ROOT CAUSE: Use Telegram proxy-secret (binary file) not user secret
-//! - Streaming handshake response (no fixed-size read deadlock)
-//! - Health monitoring + reconnection
-//! - Hex diagnostics for debugging
-
-use std::collections::HashMap;
-use std::net::{IpAddr, Ipv4Addr, SocketAddr};
-use std::sync::Arc;
-use std::sync::atomic::{AtomicU64, Ordering};
-use std::time::Duration;
-use bytes::{Bytes, BytesMut};
-use tokio::io::{AsyncReadExt, AsyncWriteExt};
-use tokio::net::TcpStream;
-use tokio::sync::{mpsc, Mutex, RwLock};
-use tokio::time::{timeout, Instant};
-use tracing::{debug, info, trace, warn, error};
-
-use crate::crypto::{crc32, derive_middleproxy_keys, AesCbc, SecureRandom};
-use crate::error::{ProxyError, Result};
-use crate::protocol::constants::*;
-
-// ========== Proxy Secret Fetching ==========
-
-/// Fetch the Telegram proxy-secret binary file.
-///
-/// This is NOT the user secret (-S flag, 16 bytes hex for clients).
-/// This is the infrastructure secret (--aes-pwd in C MTProxy),
-/// a binary file of 32-512 bytes used for ME RPC key derivation.
-///
-/// Strategy: try local cache, then download from Telegram.
-pub async fn fetch_proxy_secret(cache_path: Option<&str>) -> Result<Vec<u8>> {
-    let cache = cache_path.unwrap_or("proxy-secret");
-
-    // 1. Try local cache (< 24h old)
-    if let Ok(metadata) = tokio::fs::metadata(cache).await {
-        if let Ok(modified) = metadata.modified() {
-            let age = std::time::SystemTime::now()
-                .duration_since(modified)
-                .unwrap_or(Duration::from_secs(u64::MAX));
-            if age < Duration::from_secs(86400) {
-                if let Ok(data) = tokio::fs::read(cache).await {
-                    if data.len() >= 32 {
-                        info!(
-                            path = cache,
-                            len = data.len(),
-                            age_hours = age.as_secs() / 3600,
-                            "Loaded proxy-secret from cache"
-                        );
-                        return Ok(data);
-                    }
-                    warn!(path = cache, len = data.len(), "Cached proxy-secret too short");
-                }
-            }
-        }
-    }
-
-    // 2. Download from Telegram
-    info!("Downloading proxy-secret from core.telegram.org...");
-    let data = download_proxy_secret().await?;
-
-    // 3. Cache locally (best-effort)
-    if let Err(e) = tokio::fs::write(cache, &data).await {
-        warn!(error = %e, "Failed to cache proxy-secret (non-fatal)");
-    } else {
-        debug!(path = cache, len = data.len(), "Cached proxy-secret");
-    }
-
-    Ok(data)
-}
-
-async fn download_proxy_secret() -> Result<Vec<u8>> {
-    let url = "https://core.telegram.org/getProxySecret";
-    let resp = reqwest::get(url)
-        .await
-        .map_err(|e| ProxyError::Proxy(format!("Failed to download proxy-secret: {}", e)))?;
-
-    if !resp.status().is_success() {
-        return Err(ProxyError::Proxy(format!(
-            "proxy-secret download HTTP {}", resp.status()
-        )));
-    }
-
-    let data = resp.bytes().await
-        .map_err(|e| ProxyError::Proxy(format!("Read proxy-secret body: {}", e)))?
-        .to_vec();
-
-    if data.len() < 32 {
-        return Err(ProxyError::Proxy(format!(
-            "proxy-secret too short: {} bytes (need >= 32)", data.len()
-        )));
-    }
-
-    info!(len = data.len(), "Downloaded proxy-secret OK");
-    Ok(data)
-}
-
-// ========== RPC Frame helpers ==========
-
-/// Build an RPC frame: [len(4) | seq_no(4) | payload | crc32(4)]
-fn build_rpc_frame(seq_no: i32, payload: &[u8]) -> Vec<u8> {
-    let total_len = (4 + 4 + payload.len() + 4) as u32;
-    let mut f = Vec::with_capacity(total_len as usize);
-    f.extend_from_slice(&total_len.to_le_bytes());
-    f.extend_from_slice(&seq_no.to_le_bytes());
-    f.extend_from_slice(payload);
-    let c = crc32(&f);
-    f.extend_from_slice(&c.to_le_bytes());
-    f
-}
-
-/// Read one plaintext RPC frame. Returns (seq_no, payload).
-async fn read_rpc_frame_plaintext(
-    rd: &mut (impl AsyncReadExt + Unpin),
-) -> Result<(i32, Vec<u8>)> {
-    let mut len_buf = [0u8; 4];
-    rd.read_exact(&mut len_buf).await.map_err(ProxyError::Io)?;
-    let total_len = u32::from_le_bytes(len_buf) as usize;
-
-    if total_len < 12 || total_len > (1 << 24) {
-        return Err(ProxyError::InvalidHandshake(
-            format!("Bad RPC frame length: {}", total_len),
-        ));
-    }
-
-    let mut rest = vec![0u8; total_len - 4];
-    rd.read_exact(&mut rest).await.map_err(ProxyError::Io)?;
-
-    let mut full = Vec::with_capacity(total_len);
-    full.extend_from_slice(&len_buf);
-    full.extend_from_slice(&rest);
-
-    let crc_offset = total_len - 4;
-    let expected_crc = u32::from_le_bytes([
-        full[crc_offset], full[crc_offset + 1],
-        full[crc_offset + 2], full[crc_offset + 3],
-    ]);
-    let actual_crc = crc32(&full[..crc_offset]);
-    if expected_crc != actual_crc {
-        return Err(ProxyError::InvalidHandshake(
-            format!("CRC mismatch: 0x{:08x} vs 0x{:08x}", expected_crc, actual_crc),
-        ));
-    }
-
-    let seq_no = i32::from_le_bytes([full[4], full[5], full[6], full[7]]);
-    let payload = full[8..crc_offset].to_vec();
-    Ok((seq_no, payload))
-}
-
-// ========== RPC Nonce (32 bytes payload) ==========
-
-fn build_nonce_payload(key_selector: u32, crypto_ts: u32, nonce: &[u8; 16]) -> [u8; 32] {
-    let mut p = [0u8; 32];
-    p[0..4].copy_from_slice(&RPC_NONCE_U32.to_le_bytes());
-    p[4..8].copy_from_slice(&key_selector.to_le_bytes());
-    p[8..12].copy_from_slice(&RPC_CRYPTO_AES_U32.to_le_bytes());
-    p[12..16].copy_from_slice(&crypto_ts.to_le_bytes());
-    p[16..32].copy_from_slice(nonce);
-    p
-}
-
-fn parse_nonce_payload(d: &[u8]) -> Result<(u32, u32, [u8; 16])> {
-    if d.len() < 32 {
-        return Err(ProxyError::InvalidHandshake(
-            format!("Nonce payload too short: {} bytes", d.len()),
-        ));
-    }
-    let t = u32::from_le_bytes([d[0], d[1], d[2], d[3]]);
-    if t != RPC_NONCE_U32 {
-        return Err(ProxyError::InvalidHandshake(
-            format!("Expected RPC_NONCE 0x{:08x}, got 0x{:08x}", RPC_NONCE_U32, t),
-        ));
-    }
-    let schema = u32::from_le_bytes([d[8], d[9], d[10], d[11]]);
-    let ts = u32::from_le_bytes([d[12], d[13], d[14], d[15]]);
-    let mut nonce = [0u8; 16];
-    nonce.copy_from_slice(&d[16..32]);
-    Ok((schema, ts, nonce))
-}
-
-// ========== RPC Handshake (32 bytes payload) ==========
-
-fn build_handshake_payload(our_ip: u32, our_port: u16, peer_ip: u32, peer_port: u16) -> [u8; 32] {
-    let mut p = [0u8; 32];
-    p[0..4].copy_from_slice(&RPC_HANDSHAKE_U32.to_le_bytes());
-    // flags = 0 at offset 4..8
-
-    // sender_pid: {ip(4), port(2), pid(2), utime(4)} at offset 8..20
-    p[8..12].copy_from_slice(&our_ip.to_le_bytes());
-    p[12..14].copy_from_slice(&our_port.to_le_bytes());
-    let pid = (std::process::id() & 0xFFFF) as u16;
-    p[14..16].copy_from_slice(&pid.to_le_bytes());
-    let utime = std::time::SystemTime::now()
-        .duration_since(std::time::UNIX_EPOCH)
-        .unwrap_or_default()
-        .as_secs() as u32;
-    p[16..20].copy_from_slice(&utime.to_le_bytes());
-
-    // peer_pid: {ip(4), port(2), pid(2), utime(4)} at offset 20..32
-    p[20..24].copy_from_slice(&peer_ip.to_le_bytes());
-    p[24..26].copy_from_slice(&peer_port.to_le_bytes());
-    p
-}
-
-// ========== CBC helpers ==========
-
-fn cbc_encrypt_padded(key: &[u8; 32], iv: &[u8; 16], plaintext: &[u8]) -> Result<(Vec<u8>, [u8; 16])> {
-    let pad = (16 - (plaintext.len() % 16)) % 16;
-    let mut buf = plaintext.to_vec();
-    let pad_pattern: [u8; 4] = [0x04, 0x00, 0x00, 0x00];
-    for i in 0..pad {
-        buf.push(pad_pattern[i % 4]);
-    }
-    let cipher = AesCbc::new(*key, *iv);
-    cipher.encrypt_in_place(&mut buf)
-        .map_err(|e| ProxyError::Crypto(format!("CBC encrypt: {}", e)))?;
-    let mut new_iv = [0u8; 16];
-    if buf.len() >= 16 {
-        new_iv.copy_from_slice(&buf[buf.len() - 16..]);
-    }
-    Ok((buf, new_iv))
-}
-
-fn cbc_decrypt_inplace(key: &[u8; 32], iv: &[u8; 16], data: &mut [u8]) -> Result<[u8; 16]> {
-    let mut new_iv = [0u8; 16];
-    if data.len() >= 16 {
-        new_iv.copy_from_slice(&data[data.len() - 16..]);
-    }
-    AesCbc::new(*key, *iv)
-        .decrypt_in_place(data)
-        .map_err(|e| ProxyError::Crypto(format!("CBC decrypt: {}", e)))?;
-    Ok(new_iv)
-}
-
-// ========== IPv4 helpers ==========
-
-fn ipv4_to_mapped_v6(ip: Ipv4Addr) -> [u8; 16] {
-    let mut buf = [0u8; 16];
-    buf[10] = 0xFF;
-    buf[11] = 0xFF;
-    let o = ip.octets();
-    buf[12] = o[0]; buf[13] = o[1]; buf[14] = o[2]; buf[15] = o[3];
-    buf
-}
-
-fn addr_to_ip_u32(addr: &SocketAddr) -> u32 {
-    match addr.ip() {
-        IpAddr::V4(v4) => u32::from_be_bytes(v4.octets()),
-        IpAddr::V6(v6) => {
-            if let Some(v4) = v6.to_ipv4_mapped() {
-                u32::from_be_bytes(v4.octets())
-            } else { 0 }
-        }
-    }
-}
-
-// ========== ME Response ==========
-
-#[derive(Debug)]
-pub enum MeResponse {
-    Data(Bytes),
-    Ack(u32),
-    Close,
-}
-
-// ========== Connection Registry ==========
-
-pub struct ConnRegistry {
-    map: RwLock<HashMap<u64, mpsc::Sender<MeResponse>>>,
-    next_id: AtomicU64,
-}
-
-impl ConnRegistry {
-    pub fn new() -> Self {
-        Self {
-            map: RwLock::new(HashMap::new()),
-            next_id: AtomicU64::new(1),
-        }
-    }
-    pub async fn register(&self) -> (u64, mpsc::Receiver<MeResponse>) {
-        let id = self.next_id.fetch_add(1, Ordering::Relaxed);
-        let (tx, rx) = mpsc::channel(256);
-        self.map.write().await.insert(id, tx);
-        (id, rx)
-    }
-    pub async fn unregister(&self, id: u64) {
-        self.map.write().await.remove(&id);
-    }
-    pub async fn route(&self, id: u64, resp: MeResponse) -> bool {
-        let m = self.map.read().await;
-        if let Some(tx) = m.get(&id) {
-            tx.send(resp).await.is_ok()
-        } else { false }
-    }
-}
-
-// ========== RPC Writer (streaming CBC) ==========
-
-struct RpcWriter {
-    writer: tokio::io::WriteHalf<TcpStream>,
-    key: [u8; 32],
-    iv: [u8; 16],
-    seq_no: i32,
-}
-
-impl RpcWriter {
-    async fn send(&mut self, payload: &[u8]) -> Result<()> {
-        let frame = build_rpc_frame(self.seq_no, payload);
-        self.seq_no += 1;
-
-        let pad = (16 - (frame.len() % 16)) % 16;
-        let mut buf = frame;
-        let pad_pattern: [u8; 4] = [0x04, 0x00, 0x00, 0x00];
-        for i in 0..pad {
-            buf.push(pad_pattern[i % 4]);
-        }
-
-        let cipher = AesCbc::new(self.key, self.iv);
-        cipher.encrypt_in_place(&mut buf)
-            .map_err(|e| ProxyError::Crypto(format!("{}", e)))?;
-
-        if buf.len() >= 16 {
-            self.iv.copy_from_slice(&buf[buf.len() - 16..]);
-        }
-        self.writer.write_all(&buf).await.map_err(ProxyError::Io)
-    }
-}
-
-// ========== RPC_PROXY_REQ ==========
-
-
-fn build_proxy_req_payload(
-    conn_id: u64,
-    client_addr: SocketAddr,
-    our_addr: SocketAddr,
-    data: &[u8],
-    proxy_tag: Option<&[u8]>,
-    proto_flags: u32,
-) -> Vec<u8> {
-    // flags are pre-calculated by proto_flags_for_tag
-    // We just need to ensure FLAG_HAS_AD_TAG is set if we have a tag (it is set by default in our new function, but let's be safe)
-    let mut flags = proto_flags;
-
-    // The C code logic:
-    // flags = (transport_flags) | 0x1000 | 0x20000 | 0x8 (if tag)
-    // Our proto_flags_for_tag returns: 0x8 | 0x1000 | 0x20000 | transport_flags
-    // So we are good.
-
-    let b_cap = 128 + data.len();
-    let mut b = Vec::with_capacity(b_cap);
-
-    b.extend_from_slice(&RPC_PROXY_REQ_U32.to_le_bytes());
-    b.extend_from_slice(&flags.to_le_bytes());
-    b.extend_from_slice(&conn_id.to_le_bytes());
-
-    // Client IP (16 bytes IPv4-mapped-v6) + port (4 bytes)
-    match client_addr.ip() {
-        IpAddr::V4(v4) => b.extend_from_slice(&ipv4_to_mapped_v6(v4)),
-        IpAddr::V6(v6) => b.extend_from_slice(&v6.octets()),
-    }
-    b.extend_from_slice(&(client_addr.port() as u32).to_le_bytes());
-
-    // Our IP (16 bytes) + port (4 bytes)
-    match our_addr.ip() {
-        IpAddr::V4(v4) => b.extend_from_slice(&ipv4_to_mapped_v6(v4)),
-        IpAddr::V6(v6) => b.extend_from_slice(&v6.octets()),
-    }
-    b.extend_from_slice(&(our_addr.port() as u32).to_le_bytes());
-
-    // Extra section (proxy_tag)
-    if flags & 12 != 0 {
-        let extra_start = b.len();
-        b.extend_from_slice(&0u32.to_le_bytes()); // placeholder
-
-        if let Some(tag) = proxy_tag {
-            b.extend_from_slice(&TL_PROXY_TAG_U32.to_le_bytes());
-            // TL string encoding
-            if tag.len() < 254 {
-                b.push(tag.len() as u8);
-                b.extend_from_slice(tag);
-                let pad = (4 - ((1 + tag.len()) % 4)) % 4;
-                b.extend(std::iter::repeat(0u8).take(pad));
-            } else {
-                b.push(0xfe);
-                let len_bytes = (tag.len() as u32).to_le_bytes();
-                b.extend_from_slice(&len_bytes[..3]);
-                b.extend_from_slice(tag);
-                let pad = (4 - (tag.len() % 4)) % 4;
-                b.extend(std::iter::repeat(0u8).take(pad));
-            }
-        }
-
-        let extra_bytes = (b.len() - extra_start - 4) as u32;
-        let eb = extra_bytes.to_le_bytes();
-        b[extra_start..extra_start + 4].copy_from_slice(&eb);
-    }
-
-    b.extend_from_slice(data);
-    b
-}
-
-// ========== ME Pool ==========
-
-pub struct MePool {
-    registry: Arc<ConnRegistry>,
-    writers: Arc<RwLock<Vec<Arc<Mutex<RpcWriter>>>>>,
-    rr: AtomicU64,
-    proxy_tag: Option<Vec<u8>>,
-    /// Telegram proxy-secret (binary, 32-512 bytes)
-    proxy_secret: Vec<u8>,
-    pool_size: usize,
-}
-
-impl MePool {
-    pub fn new(proxy_tag: Option<Vec<u8>>, proxy_secret: Vec<u8>) -> Arc<Self> {
-        Arc::new(Self {
-            registry: Arc::new(ConnRegistry::new()),
-            writers: Arc::new(RwLock::new(Vec::new())),
-            rr: AtomicU64::new(0),
-            proxy_tag,
-            proxy_secret,
-            pool_size: 2,
-        })
-    }
-
-    pub fn registry(&self) -> &Arc<ConnRegistry> {
-        &self.registry
-    }
-
-    fn writers_arc(&self) -> Arc<RwLock<Vec<Arc<Mutex<RpcWriter>>>>> {
-        self.writers.clone()
-    }
-
-    /// key_selector = first 4 bytes of proxy-secret as LE u32
-    /// C: main_secret.key_signature via union { char secret[]; int key_signature; }
-    fn key_selector(&self) -> u32 {
-        if self.proxy_secret.len() >= 4 {
-            u32::from_le_bytes([
-                self.proxy_secret[0], self.proxy_secret[1],
-                self.proxy_secret[2], self.proxy_secret[3],
-            ])
-        } else { 0 }
-    }
-
-    pub async fn init(
-        self: &Arc<Self>,
-        pool_size: usize,
-        rng: &SecureRandom,
-    ) -> Result<()> {
-        let addrs = &*TG_MIDDLE_PROXIES_FLAT_V4;
-        let ks = self.key_selector();
-        info!(
-            me_servers = addrs.len(),
-            pool_size,
-            key_selector = format_args!("0x{:08x}", ks),
-            secret_len = self.proxy_secret.len(),
-            "Initializing ME pool"
-        );
-
-        for &(ip, port) in addrs.iter() {
-            for i in 0..pool_size {
-                let addr = SocketAddr::new(ip, port);
-                match self.connect_one(addr, rng).await {
-                    Ok(()) => info!(%addr, idx = i, "ME connected"),
-                    Err(e) => warn!(%addr, idx = i, error = %e, "ME connect failed"),
-                }
-            }
-            if self.writers.read().await.len() >= pool_size {
-                break;
-            }
-        }
-
-        if self.writers.read().await.is_empty() {
-            return Err(ProxyError::Proxy("No ME connections".into()));
-        }
-        Ok(())
-    }
-
-    async fn connect_one(
-        self: &Arc<Self>,
-        addr: SocketAddr,
-        rng: &SecureRandom,
-    ) -> Result<()> {
-        let secret = &self.proxy_secret;
-        if secret.len() < 32 {
-            return Err(ProxyError::Proxy("proxy-secret too short for ME auth".into()));
-        }
-
-        // ===== TCP connect =====
-        let stream = timeout(
-            Duration::from_secs(ME_CONNECT_TIMEOUT_SECS),
-            TcpStream::connect(addr),
-        )
-        .await
-        .map_err(|_| ProxyError::ConnectionTimeout { addr: addr.to_string() })?
-        .map_err(ProxyError::Io)?;
-        stream.set_nodelay(true).ok();
-
-        let local_addr = stream.local_addr().map_err(ProxyError::Io)?;
-        let peer_addr = stream.peer_addr().map_err(ProxyError::Io)?;
-        let (mut rd, mut wr) = tokio::io::split(stream);
-
-        // ===== 1. Send RPC nonce (plaintext, seq=-2) =====
-        let my_nonce: [u8; 16] = rng.bytes(16).try_into().unwrap();
-        let crypto_ts = std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .unwrap_or_default()
-            .as_secs() as u32;
-        let ks = self.key_selector();
-
-        let nonce_payload = build_nonce_payload(ks, crypto_ts, &my_nonce);
-        let nonce_frame = build_rpc_frame(-2, &nonce_payload);
-
-        debug!(
-            %addr,
-            frame_len = nonce_frame.len(),
-            key_sel = format_args!("0x{:08x}", ks),
-            crypto_ts,
-            "Sending nonce"
-        );
-
-        wr.write_all(&nonce_frame).await.map_err(ProxyError::Io)?;
-        wr.flush().await.map_err(ProxyError::Io)?;
-
-        // ===== 2. Read server nonce (plaintext, seq=-2) =====
-        let (srv_seq, srv_nonce_payload) = timeout(
-            Duration::from_secs(ME_HANDSHAKE_TIMEOUT_SECS),
-            read_rpc_frame_plaintext(&mut rd),
-        )
-        .await
-        .map_err(|_| ProxyError::TgHandshakeTimeout)??;
-
-        if srv_seq != -2 {
-            return Err(ProxyError::InvalidHandshake(
-                format!("Expected seq=-2, got {}", srv_seq),
-            ));
-        }
-
-        let (schema, _srv_ts, srv_nonce) = parse_nonce_payload(&srv_nonce_payload)?;
-        if schema != RPC_CRYPTO_AES_U32 {
-            return Err(ProxyError::InvalidHandshake(
-                format!("Unsupported crypto schema: 0x{:x}", schema),
-            ));
-        }
-
-        debug!(%addr, "Nonce exchange OK, deriving keys");
-
-        // ===== 3. Derive AES-256-CBC keys =====
-        // C buffer layout:
-        //   [0..16]  nonce_server (srv_nonce)
-        //   [16..32] nonce_client (my_nonce)
-        //   [32..36] client_timestamp
-        //   [36..40] server_ip
-        //   [40..42] client_port
-        //   [42..48] "CLIENT" or "SERVER"
-        //   [48..52] client_ip
-        //   [52..54] server_port
-        //   [54..54+N] secret (proxy-secret binary)
-        //   [54+N..70+N] nonce_server
-        //   nonce_client(16)
-
-        let ts_bytes = crypto_ts.to_le_bytes();
-        let server_ip = addr_to_ip_u32(&peer_addr);
-        let client_ip = addr_to_ip_u32(&local_addr);
-        let server_ip_bytes = server_ip.to_le_bytes();
-        let client_ip_bytes = client_ip.to_le_bytes();
-        let server_port_bytes = peer_addr.port().to_le_bytes();
-        let client_port_bytes = local_addr.port().to_le_bytes();
-
-        let (wk, wi) = derive_middleproxy_keys(
-            &srv_nonce, &my_nonce, &ts_bytes,
-            Some(&server_ip_bytes), &client_port_bytes,
-            b"CLIENT",
-            Some(&client_ip_bytes), &server_port_bytes,
-            secret, None, None,
-        );
-        let (rk, ri) = derive_middleproxy_keys(
-            &srv_nonce, &my_nonce, &ts_bytes,
-            Some(&server_ip_bytes), &client_port_bytes,
-            b"SERVER",
-            Some(&client_ip_bytes), &server_port_bytes,
-            secret, None, None,
-        );
-
-        debug!(
-            %addr,
-            write_key = %hex::encode(&wk[..8]),
-            read_key = %hex::encode(&rk[..8]),
-            "Keys derived"
-        );
-
-        // ===== 4. Send encrypted handshake (seq=-1) =====
-        let hs_payload = build_handshake_payload(
-            client_ip, local_addr.port(),
-            server_ip, peer_addr.port(),
-        );
-        let hs_frame = build_rpc_frame(-1, &hs_payload);
-        let (encrypted_hs, write_iv) = cbc_encrypt_padded(&wk, &wi, &hs_frame)?;
-        wr.write_all(&encrypted_hs).await.map_err(ProxyError::Io)?;
-        wr.flush().await.map_err(ProxyError::Io)?;
-
-        debug!(%addr, enc_len = encrypted_hs.len(), "Sent encrypted handshake");
-
-        // ===== 5. Read encrypted handshake response (STREAMING) =====
-        // Server sends encrypted handshake. C crypto layer may send partial
-        // blocks (only complete 16-byte blocks get encrypted at a time).
-        // We read incrementally and decrypt block-by-block.
-        let deadline = Instant::now() + Duration::from_secs(ME_HANDSHAKE_TIMEOUT_SECS);
-        let mut enc_buf = BytesMut::with_capacity(256);
-        let mut dec_buf = BytesMut::with_capacity(256);
-        let mut read_iv = ri;
-        let mut handshake_ok = false;
-
-        while Instant::now() < deadline && !handshake_ok {
-            let remaining = deadline - Instant::now();
-            let mut tmp = [0u8; 256];
-            let n = match timeout(remaining, rd.read(&mut tmp)).await {
-                Ok(Ok(0)) => return Err(ProxyError::Io(std::io::Error::new(
-                    std::io::ErrorKind::UnexpectedEof, "ME closed during handshake",
-                ))),
-                Ok(Ok(n)) => n,
-                Ok(Err(e)) => return Err(ProxyError::Io(e)),
-                Err(_) => return Err(ProxyError::TgHandshakeTimeout),
-            };
-            enc_buf.extend_from_slice(&tmp[..n]);
-
-            // Decrypt complete 16-byte blocks
-            let blocks = enc_buf.len() / 16 * 16;
-            if blocks > 0 {
-                let mut chunk = vec![0u8; blocks];
-                chunk.copy_from_slice(&enc_buf[..blocks]);
-                let new_iv = cbc_decrypt_inplace(&rk, &read_iv, &mut chunk)?;
-                read_iv = new_iv;
-                dec_buf.extend_from_slice(&chunk);
-                let _ = enc_buf.split_to(blocks);
-            }
-
-            // Try to parse RPC frame from decrypted data
-            while dec_buf.len() >= 4 {
-                let fl = u32::from_le_bytes([
-                    dec_buf[0], dec_buf[1], dec_buf[2], dec_buf[3],
-                ]) as usize;
-
-                // Skip noop padding
-                if fl == 4 {
-                    let _ = dec_buf.split_to(4);
-                    continue;
-                }
-                if fl < 12 || fl > (1 << 24) {
-                    return Err(ProxyError::InvalidHandshake(
-                        format!("Bad HS response frame len: {}", fl),
-                    ));
-                }
-                if dec_buf.len() < fl {
-                    break; // need more data
-                }
-
-                let frame = dec_buf.split_to(fl);
-
-                // CRC32 check
-                let pe = fl - 4;
-                let ec = u32::from_le_bytes([
-                    frame[pe], frame[pe + 1], frame[pe + 2], frame[pe + 3],
-                ]);
-                let ac = crc32(&frame[..pe]);
-                if ec != ac {
-                    return Err(ProxyError::InvalidHandshake(
-                        format!("HS CRC mismatch: 0x{:08x} vs 0x{:08x}", ec, ac),
-                    ));
-                }
-
-                // Check type
-                let hs_type = u32::from_le_bytes([
-                    frame[8], frame[9], frame[10], frame[11],
-                ]);
-                if hs_type == RPC_HANDSHAKE_ERROR_U32 {
-                    let err_code = if frame.len() >= 16 {
-                        i32::from_le_bytes([frame[12], frame[13], frame[14], frame[15]])
-                    } else { -1 };
-                    return Err(ProxyError::InvalidHandshake(
-                        format!("ME rejected handshake (error={})", err_code),
-                    ));
-                }
-                if hs_type != RPC_HANDSHAKE_U32 {
-                    return Err(ProxyError::InvalidHandshake(
-                        format!("Expected HANDSHAKE 0x{:08x}, got 0x{:08x}", RPC_HANDSHAKE_U32, hs_type),
-                    ));
-                }
-
-                handshake_ok = true;
-                break;
-            }
-        }
-
-        if !handshake_ok {
-            return Err(ProxyError::TgHandshakeTimeout);
-        }
-
-        info!(%addr, "RPC handshake OK");
-
-        // ===== 6. Setup writer + reader =====
-        let rpc_w = Arc::new(Mutex::new(RpcWriter {
-            writer: wr,
-            key: wk,
-            iv: write_iv,
-            seq_no: 0,
-        }));
-        self.writers.write().await.push(rpc_w.clone());
-
-        let reg = self.registry.clone();
-        let w_pong = rpc_w.clone();
-        let w_pool = self.writers_arc();
-        tokio::spawn(async move {
-            if let Err(e) = reader_loop(rd, rk, read_iv, reg, enc_buf, dec_buf, w_pong.clone()).await {
-                warn!(error = %e, "ME reader ended");
-            }
-            // Remove dead writer from pool
-            let mut ws = w_pool.write().await;
-            ws.retain(|w| !Arc::ptr_eq(w, &w_pong));
-            info!(remaining = ws.len(), "Dead ME writer removed from pool");
-        });
-
-        Ok(())
-    }
-
-    pub async fn send_proxy_req(
-        &self,
-        conn_id: u64,
-        client_addr: SocketAddr,
-        our_addr: SocketAddr,
-        data: &[u8],
-        proto_flags: u32,
-    ) -> Result<()> {
-        let payload = build_proxy_req_payload(
-            conn_id, client_addr, our_addr, data,
-            self.proxy_tag.as_deref(), proto_flags,
-        );
-        loop {
-            let ws = self.writers.read().await;
-            if ws.is_empty() {
-                return Err(ProxyError::Proxy("All ME connections dead".into()));
-            }
-            let idx = self.rr.fetch_add(1, Ordering::Relaxed) as usize % ws.len();
-            let w = ws[idx].clone();
-            drop(ws);
-            match w.lock().await.send(&payload).await {
-                Ok(()) => return Ok(()),
-                Err(e) => {
-                    warn!(error = %e, "ME write failed, removing dead conn");
-                    let mut ws = self.writers.write().await;
-                    ws.retain(|o| !Arc::ptr_eq(o, &w));
-                    if ws.is_empty() {
-                        return Err(ProxyError::Proxy("All ME connections dead".into()));
-                    }
-                }
-            }
-        }
-    }
-
-    pub async fn send_close(&self, conn_id: u64) -> Result<()> {
-        let ws = self.writers.read().await;
-        if !ws.is_empty() {
-            let w = ws[0].clone();
-            drop(ws);
-            let mut p = Vec::with_capacity(12);
-            p.extend_from_slice(&RPC_CLOSE_EXT_U32.to_le_bytes());
-            p.extend_from_slice(&conn_id.to_le_bytes());
-            if let Err(e) = w.lock().await.send(&p).await {
-                debug!(error = %e, "ME close write failed");
-                let mut ws = self.writers.write().await;
-                ws.retain(|o| !Arc::ptr_eq(o, &w));
-            }
-        }
-        self.registry.unregister(conn_id).await;
-        Ok(())
-    }
-
-    pub fn connection_count(&self) -> usize {
-        self.writers.try_read().map(|w| w.len()).unwrap_or(0)
-    }
-}
-
-// ========== Reader Loop ==========
-
-async fn reader_loop(
-    mut rd: tokio::io::ReadHalf<TcpStream>,
-    dk: [u8; 32],
-    mut div: [u8; 16],
-    reg: Arc<ConnRegistry>,
-    mut enc_leftover: BytesMut,
-    mut dec: BytesMut,
-    writer: Arc<Mutex<RpcWriter>>,
-) -> Result<()> {
-    let mut raw = enc_leftover;
-    loop {
-        let mut tmp = [0u8; 16384];
-        let n = rd.read(&mut tmp).await.map_err(ProxyError::Io)?;
-        if n == 0 { return Ok(()); }
-        raw.extend_from_slice(&tmp[..n]);
-
-        // Decrypt complete 16-byte blocks
-        let blocks = raw.len() / 16 * 16;
-        if blocks > 0 {
-            let mut new_iv = [0u8; 16];
-            new_iv.copy_from_slice(&raw[blocks - 16..blocks]);
-            let mut chunk = vec![0u8; blocks];
-            chunk.copy_from_slice(&raw[..blocks]);
-            AesCbc::new(dk, div)
-                .decrypt_in_place(&mut chunk)
-                .map_err(|e| ProxyError::Crypto(format!("{}", e)))?;
-            div = new_iv;
-            dec.extend_from_slice(&chunk);
-            let _ = raw.split_to(blocks);
-        }
-
-        // Parse RPC frames
-        while dec.len() >= 12 {
-            let fl = u32::from_le_bytes([dec[0], dec[1], dec[2], dec[3]]) as usize;
-            if fl == 4 { let _ = dec.split_to(4); continue; }
-            if fl < 12 || fl > (1 << 24) {
-                warn!(frame_len = fl, "Invalid RPC frame len");
-                dec.clear();
-                break;
-            }
-            if dec.len() < fl { break; }
-
-            let frame = dec.split_to(fl);
-            let pe = fl - 4;
-            let ec = u32::from_le_bytes([frame[pe], frame[pe+1], frame[pe+2], frame[pe+3]]);
-            if crc32(&frame[..pe]) != ec {
-                warn!("CRC mismatch in data frame");
-                continue;
-            }
-
-            let payload = &frame[8..pe];
-            if payload.len() < 4 { continue; }
-            let pt = u32::from_le_bytes([payload[0], payload[1], payload[2], payload[3]]);
-            let body = &payload[4..];
-
-            if pt == RPC_PROXY_ANS_U32 && body.len() >= 12 {
-                let flags = u32::from_le_bytes(body[0..4].try_into().unwrap());
-                let cid = u64::from_le_bytes(body[4..12].try_into().unwrap());
-                let data = Bytes::copy_from_slice(&body[12..]);
-                trace!(cid, len = data.len(), flags, "ANS");
-                reg.route(cid, MeResponse::Data(data)).await;
-            } else if pt == RPC_SIMPLE_ACK_U32 && body.len() >= 12 {
-                let cid = u64::from_le_bytes(body[0..8].try_into().unwrap());
-                let cfm = u32::from_le_bytes(body[8..12].try_into().unwrap());
-                trace!(cid, cfm, "ACK");
-                reg.route(cid, MeResponse::Ack(cfm)).await;
-            } else if pt == RPC_CLOSE_EXT_U32 && body.len() >= 8 {
-                let cid = u64::from_le_bytes(body[0..8].try_into().unwrap());
-                debug!(cid, "CLOSE_EXT from ME");
-                reg.route(cid, MeResponse::Close).await;
-                reg.unregister(cid).await;
-            } else if pt == RPC_CLOSE_CONN_U32 && body.len() >= 8 {
-                let cid = u64::from_le_bytes(body[0..8].try_into().unwrap());
-                debug!(cid, "CLOSE_CONN from ME");
-                reg.route(cid, MeResponse::Close).await;
-                reg.unregister(cid).await;
-            } else if pt == RPC_PING_U32 && body.len() >= 8 {
-                let ping_id = i64::from_le_bytes(body[0..8].try_into().unwrap());
-                trace!(ping_id, "RPC_PING -> PONG");
-                let mut pong = Vec::with_capacity(12);
-                pong.extend_from_slice(&RPC_PONG_U32.to_le_bytes());
-                pong.extend_from_slice(&ping_id.to_le_bytes());
-                if let Err(e) = writer.lock().await.send(&pong).await {
-                    warn!(error = %e, "PONG send failed");
-                    break;
-                }
-            } else {
-                debug!(rpc_type = format_args!("0x{:08x}", pt), len = body.len(), "Unknown RPC");
-            }
-        }
-    }
-}
-
-// ========== Proto flags ==========
-
-/// Map ProtoTag to C-compatible RPC_PROXY_REQ transport flags.
-/// C: RPC_F_COMPACT(0x40000000)=abridged, RPC_F_MEDIUM(0x20000000)=intermediate/secure
-/// The 0x1000(magic) and 0x8(proxy_tag) are added inside build_proxy_req_payload.
-
-pub fn proto_flags_for_tag(tag: crate::protocol::constants::ProtoTag) -> u32 {
-    use crate::protocol::constants::*;
-    let mut flags = RPC_FLAG_HAS_AD_TAG | RPC_FLAG_MAGIC | RPC_FLAG_EXTMODE2;
-    match tag {
-        ProtoTag::Abridged     => flags | RPC_FLAG_ABRIDGED,
-        ProtoTag::Intermediate => flags | RPC_FLAG_INTERMEDIATE,
-        ProtoTag::Secure       => flags | RPC_FLAG_PAD | RPC_FLAG_INTERMEDIATE,
-    }
-}
-
-
-// ========== Health Monitor (Phase 4) ==========
-
-pub async fn me_health_monitor(
-    pool: Arc<MePool>,
-    rng: Arc<SecureRandom>,
-    min_connections: usize,
-) {
-    loop {
-        tokio::time::sleep(Duration::from_secs(30)).await;
-        let current = pool.writers.read().await.len();
-        if current < min_connections {
-            warn!(current, min = min_connections, "ME pool below minimum, reconnecting...");
-            let addrs = TG_MIDDLE_PROXIES_FLAT_V4.clone();
-            for &(ip, port) in addrs.iter() {
-                let needed = min_connections.saturating_sub(pool.writers.read().await.len());
-                if needed == 0 { break; }
-                for _ in 0..needed {
-                    let addr = SocketAddr::new(ip, port);
-                    match pool.connect_one(addr, &rng).await {
-                        Ok(()) => info!(%addr, "ME reconnected"),
-                        Err(e) => debug!(%addr, error = %e, "ME reconnect failed"),
-                    }
-                }
-            }
-        }
-    }
-}

src/transport/middle_proxy/codec.rs

@@ -174,6 +174,7 @@ impl RpcWriter {
         if buf.len() >= 16 {
             self.iv.copy_from_slice(&buf[buf.len() - 16..]);
         }
-        self.writer.write_all(&buf).await.map_err(ProxyError::Io)
+        self.writer.write_all(&buf).await.map_err(ProxyError::Io)?;
+        self.writer.flush().await.map_err(ProxyError::Io)
     }
 }

src/transport/middle_proxy/config_updater.rs

@@ -0,0 +1,113 @@
+use std::collections::HashMap;
+use std::net::IpAddr;
+use std::sync::Arc;
+use std::time::Duration;
+
+use regex::Regex;
+use httpdate;
+use tracing::{debug, info, warn};
+
+use crate::error::Result;
+
+use super::MePool;
+use super::secret::download_proxy_secret;
+use crate::crypto::SecureRandom;
+use std::time::SystemTime;
+
+#[derive(Debug, Clone, Default)]
+pub struct ProxyConfigData {
+    pub map: HashMap<i32, Vec<(IpAddr, u16)>>,
+    pub default_dc: Option<i32>,
+}
+
+pub async fn fetch_proxy_config(url: &str) -> Result<ProxyConfigData> {
+    let resp = reqwest::get(url)
+        .await
+        .map_err(|e| crate::error::ProxyError::Proxy(format!("fetch_proxy_config GET failed: {e}")))?
+        ;
+
+    if let Some(date) = resp.headers().get(reqwest::header::DATE) {
+        if let Ok(date_str) = date.to_str() {
+            if let Ok(server_time) = httpdate::parse_http_date(date_str) {
+                if let Ok(skew) = SystemTime::now().duration_since(server_time).or_else(|e| {
+                    server_time.duration_since(SystemTime::now()).map_err(|_| e)
+                }) {
+                    let skew_secs = skew.as_secs();
+                    if skew_secs > 60 {
+                        warn!(skew_secs, "Time skew >60s detected from fetch_proxy_config Date header");
+                    } else if skew_secs > 30 {
+                        warn!(skew_secs, "Time skew >30s detected from fetch_proxy_config Date header");
+                    }
+                }
+            }
+        }
+    }
+
+    let text = resp
+        .text()
+        .await
+        .map_err(|e| crate::error::ProxyError::Proxy(format!("fetch_proxy_config read failed: {e}")))?;
+
+    let re_proxy = Regex::new(r"proxy_for\s+(-?\d+)\s+([^\s:]+):(\d+)\s*;").unwrap();
+    let re_default = Regex::new(r"default\s+(-?\d+)\s*;").unwrap();
+
+    let mut map: HashMap<i32, Vec<(IpAddr, u16)>> = HashMap::new();
+    for cap in re_proxy.captures_iter(&text) {
+        if let (Some(dc), Some(host), Some(port)) = (cap.get(1), cap.get(2), cap.get(3)) {
+            if let Ok(dc_idx) = dc.as_str().parse::<i32>() {
+                if let Ok(ip) = host.as_str().parse::<IpAddr>() {
+                    if let Ok(port_num) = port.as_str().parse::<u16>() {
+                        map.entry(dc_idx).or_default().push((ip, port_num));
+                    }
+                }
+            }
+        }
+    }
+
+    let default_dc = re_default
+        .captures(&text)
+        .and_then(|c| c.get(1))
+        .and_then(|m| m.as_str().parse::<i32>().ok());
+
+    Ok(ProxyConfigData { map, default_dc })
+}
+
+pub async fn me_config_updater(pool: Arc<MePool>, rng: Arc<SecureRandom>, interval: Duration) {
+    let mut tick = tokio::time::interval(interval);
+    // skip immediate tick to avoid double-fetch right after startup
+    tick.tick().await;
+    loop {
+        tick.tick().await;
+
+        // Update proxy config v4
+        if let Ok(cfg) = fetch_proxy_config("https://core.telegram.org/getProxyConfig").await {
+            let changed = pool.update_proxy_maps(cfg.map.clone(), None).await;
+            if let Some(dc) = cfg.default_dc {
+                pool.default_dc.store(dc, std::sync::atomic::Ordering::Relaxed);
+            }
+            if changed {
+                info!("ME config updated (v4), reconciling connections");
+                pool.reconcile_connections(&rng).await;
+            } else {
+                debug!("ME config v4 unchanged");
+            }
+        } else {
+            warn!("getProxyConfig update failed");
+        }
+
+        // Update proxy config v6 (optional)
+        if let Ok(cfg_v6) = fetch_proxy_config("https://core.telegram.org/getProxyConfigV6").await {
+            let _ = pool.update_proxy_maps(HashMap::new(), Some(cfg_v6.map)).await;
+        }
+
+        // Update proxy-secret
+        match download_proxy_secret().await {
+            Ok(secret) => {
+                if pool.update_secret(secret).await {
+                    info!("proxy-secret updated and pool reconnect scheduled");
+                }
+            }
+            Err(e) => warn!(error = %e, "proxy-secret update failed"),
+        }
+    }
+}

src/transport/middle_proxy/handshake.rs

@@ -0,0 +1,418 @@
+use std::net::{IpAddr, SocketAddr};
+use std::time::{Duration, Instant};
+use socket2::{SockRef, TcpKeepalive};
+#[cfg(target_os = "linux")]
+use libc;
+#[cfg(target_os = "linux")]
+use std::os::fd::{AsRawFd, RawFd};
+#[cfg(target_os = "linux")]
+use std::os::raw::c_int;
+
+use bytes::BytesMut;
+use tokio::io::{AsyncReadExt, AsyncWriteExt, ReadHalf, WriteHalf};
+use tokio::net::TcpStream;
+use tokio::time::timeout;
+use tracing::{debug, info, warn};
+
+use crate::crypto::{SecureRandom, build_middleproxy_prekey, derive_middleproxy_keys, sha256};
+use crate::error::{ProxyError, Result};
+use crate::network::IpFamily;
+use crate::protocol::constants::{
+    ME_CONNECT_TIMEOUT_SECS, ME_HANDSHAKE_TIMEOUT_SECS, RPC_CRYPTO_AES_U32, RPC_HANDSHAKE_ERROR_U32,
+    RPC_HANDSHAKE_U32, RPC_PING_U32, RPC_PONG_U32, RPC_NONCE_U32,
+};
+
+use super::codec::{
+    build_handshake_payload, build_nonce_payload, build_rpc_frame, cbc_decrypt_inplace,
+    cbc_encrypt_padded, parse_nonce_payload, read_rpc_frame_plaintext,
+};
+use super::wire::{extract_ip_material, IpMaterial};
+use super::MePool;
+
+/// Result of a successful ME handshake with timings.
+pub(crate) struct HandshakeOutput {
+    pub rd: ReadHalf<TcpStream>,
+    pub wr: WriteHalf<TcpStream>,
+    pub read_key: [u8; 32],
+    pub read_iv: [u8; 16],
+    pub write_key: [u8; 32],
+    pub write_iv: [u8; 16],
+    pub handshake_ms: f64,
+}
+
+impl MePool {
+    /// TCP connect with timeout + return RTT in milliseconds.
+    pub(crate) async fn connect_tcp(&self, addr: SocketAddr) -> Result<(TcpStream, f64)> {
+        let start = Instant::now();
+        let stream = timeout(Duration::from_secs(ME_CONNECT_TIMEOUT_SECS), TcpStream::connect(addr))
+            .await
+            .map_err(|_| ProxyError::ConnectionTimeout { addr: addr.to_string() })??;
+        let connect_ms = start.elapsed().as_secs_f64() * 1000.0;
+        stream.set_nodelay(true).ok();
+        if let Err(e) = Self::configure_keepalive(&stream) {
+            warn!(error = %e, "ME keepalive setup failed");
+        }
+        #[cfg(target_os = "linux")]
+        if let Err(e) = Self::configure_user_timeout(stream.as_raw_fd()) {
+            warn!(error = %e, "ME TCP_USER_TIMEOUT setup failed");
+        }
+        Ok((stream, connect_ms))
+    }
+
+    fn configure_keepalive(stream: &TcpStream) -> std::io::Result<()> {
+        let sock = SockRef::from(stream);
+        let ka = TcpKeepalive::new()
+            .with_time(Duration::from_secs(30))
+            .with_interval(Duration::from_secs(10))
+            .with_retries(3);
+        sock.set_tcp_keepalive(&ka)?;
+        sock.set_keepalive(true)?;
+        Ok(())
+    }
+
+    #[cfg(target_os = "linux")]
+    fn configure_user_timeout(fd: RawFd) -> std::io::Result<()> {
+        let timeout_ms: c_int = 30_000;
+        let rc = unsafe {
+            libc::setsockopt(
+                fd,
+                libc::IPPROTO_TCP,
+                libc::TCP_USER_TIMEOUT,
+                &timeout_ms as *const _ as *const libc::c_void,
+                std::mem::size_of_val(&timeout_ms) as libc::socklen_t,
+            )
+        };
+        if rc != 0 {
+            return Err(std::io::Error::last_os_error());
+        }
+        Ok(())
+    }
+
+    /// Perform full ME RPC handshake on an established TCP stream.
+    /// Returns cipher keys/ivs and split halves; does not register writer.
+    pub(crate) async fn handshake_only(
+        &self,
+        stream: TcpStream,
+        addr: SocketAddr,
+        rng: &SecureRandom,
+    ) -> Result<HandshakeOutput> {
+        let hs_start = Instant::now();
+
+        let local_addr = stream.local_addr().map_err(ProxyError::Io)?;
+        let peer_addr = stream.peer_addr().map_err(ProxyError::Io)?;
+
+        let _ = self.maybe_detect_nat_ip(local_addr.ip()).await;
+        let family = if local_addr.ip().is_ipv4() {
+            IpFamily::V4
+        } else {
+            IpFamily::V6
+        };
+        let reflected = if self.nat_probe {
+            self.maybe_reflect_public_addr(family).await
+        } else {
+            None
+        };
+
+        let local_addr_nat = self.translate_our_addr_with_reflection(local_addr, reflected);
+        let peer_addr_nat = SocketAddr::new(self.translate_ip_for_nat(peer_addr.ip()), peer_addr.port());
+        let (mut rd, mut wr) = tokio::io::split(stream);
+
+        let my_nonce: [u8; 16] = rng.bytes(16).try_into().unwrap();
+        let crypto_ts = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap_or_default()
+            .as_secs() as u32;
+
+        let ks = self.key_selector().await;
+        let nonce_payload = build_nonce_payload(ks, crypto_ts, &my_nonce);
+        let nonce_frame = build_rpc_frame(-2, &nonce_payload);
+        let dump = hex_dump(&nonce_frame[..nonce_frame.len().min(44)]);
+        info!(
+            key_selector = format_args!("0x{ks:08x}"),
+            crypto_ts,
+            frame_len = nonce_frame.len(),
+            nonce_frame_hex = %dump,
+            "Sending ME nonce frame"
+        );
+        wr.write_all(&nonce_frame).await.map_err(ProxyError::Io)?;
+        wr.flush().await.map_err(ProxyError::Io)?;
+
+        let (srv_seq, srv_nonce_payload) = timeout(
+            Duration::from_secs(ME_HANDSHAKE_TIMEOUT_SECS),
+            read_rpc_frame_plaintext(&mut rd),
+        )
+        .await
+        .map_err(|_| ProxyError::TgHandshakeTimeout)??;
+
+        if srv_seq != -2 {
+            return Err(ProxyError::InvalidHandshake(format!("Expected seq=-2, got {srv_seq}")));
+        }
+
+        let (srv_key_select, schema, srv_ts, srv_nonce) = parse_nonce_payload(&srv_nonce_payload)?;
+        if schema != RPC_CRYPTO_AES_U32 {
+            warn!(schema = format_args!("0x{schema:08x}"), "Unsupported ME crypto schema");
+            return Err(ProxyError::InvalidHandshake(format!(
+                "Unsupported crypto schema: 0x{schema:x}"
+            )));
+        }
+
+        if srv_key_select != ks {
+            return Err(ProxyError::InvalidHandshake(format!(
+                "Server key_select 0x{srv_key_select:08x} != client 0x{ks:08x}"
+            )));
+        }
+
+        let skew = crypto_ts.abs_diff(srv_ts);
+        if skew > 30 {
+            return Err(ProxyError::InvalidHandshake(format!(
+                "nonce crypto_ts skew too large: client={crypto_ts}, server={srv_ts}, skew={skew}s"
+            )));
+        }
+
+        info!(
+            %local_addr,
+            %local_addr_nat,
+            reflected_ip = reflected.map(|r| r.ip()).as_ref().map(ToString::to_string),
+            %peer_addr,
+            %peer_addr_nat,
+            key_selector = format_args!("0x{ks:08x}"),
+            crypto_schema = format_args!("0x{schema:08x}"),
+            skew_secs = skew,
+            "ME key derivation parameters"
+        );
+
+        let ts_bytes = crypto_ts.to_le_bytes();
+        let server_port_bytes = peer_addr_nat.port().to_le_bytes();
+        let client_port_bytes = local_addr_nat.port().to_le_bytes();
+
+        let server_ip = extract_ip_material(peer_addr_nat);
+        let client_ip = extract_ip_material(local_addr_nat);
+
+        let (srv_ip_opt, clt_ip_opt, clt_v6_opt, srv_v6_opt, hs_our_ip, hs_peer_ip) = match (server_ip, client_ip) {
+            (IpMaterial::V4(mut srv), IpMaterial::V4(mut clt)) => {
+                srv.reverse();
+                clt.reverse();
+                (Some(srv), Some(clt), None, None, clt, srv)
+            }
+            (IpMaterial::V6(srv), IpMaterial::V6(clt)) => {
+                let zero = [0u8; 4];
+                (None, None, Some(clt), Some(srv), zero, zero)
+            }
+            _ => {
+                return Err(ProxyError::InvalidHandshake(
+                    "mixed IPv4/IPv6 endpoints are not supported for ME key derivation".to_string(),
+                ));
+            }
+        };
+
+        let diag_level: u8 = std::env::var("ME_DIAG").ok().and_then(|v| v.parse().ok()).unwrap_or(0);
+
+        let secret: Vec<u8> = self.proxy_secret.read().await.clone();
+
+        let prekey_client = build_middleproxy_prekey(
+            &srv_nonce,
+            &my_nonce,
+            &ts_bytes,
+            srv_ip_opt.as_ref().map(|x| &x[..]),
+            &client_port_bytes,
+            b"CLIENT",
+            clt_ip_opt.as_ref().map(|x| &x[..]),
+            &server_port_bytes,
+            &secret,
+            clt_v6_opt.as_ref(),
+            srv_v6_opt.as_ref(),
+        );
+        let prekey_server = build_middleproxy_prekey(
+            &srv_nonce,
+            &my_nonce,
+            &ts_bytes,
+            srv_ip_opt.as_ref().map(|x| &x[..]),
+            &client_port_bytes,
+            b"SERVER",
+            clt_ip_opt.as_ref().map(|x| &x[..]),
+            &server_port_bytes,
+            &secret,
+            clt_v6_opt.as_ref(),
+            srv_v6_opt.as_ref(),
+        );
+
+        let (wk, wi) = derive_middleproxy_keys(
+            &srv_nonce,
+            &my_nonce,
+            &ts_bytes,
+            srv_ip_opt.as_ref().map(|x| &x[..]),
+            &client_port_bytes,
+            b"CLIENT",
+            clt_ip_opt.as_ref().map(|x| &x[..]),
+            &server_port_bytes,
+            &secret,
+            clt_v6_opt.as_ref(),
+            srv_v6_opt.as_ref(),
+        );
+        let (rk, ri) = derive_middleproxy_keys(
+            &srv_nonce,
+            &my_nonce,
+            &ts_bytes,
+            srv_ip_opt.as_ref().map(|x| &x[..]),
+            &client_port_bytes,
+            b"SERVER",
+            clt_ip_opt.as_ref().map(|x| &x[..]),
+            &server_port_bytes,
+            &secret,
+            clt_v6_opt.as_ref(),
+            srv_v6_opt.as_ref(),
+        );
+
+        let hs_payload = build_handshake_payload(hs_our_ip, local_addr.port(), hs_peer_ip, peer_addr.port());
+        let hs_frame = build_rpc_frame(-1, &hs_payload);
+        if diag_level >= 1 {
+            info!(
+                write_key = %hex_dump(&wk),
+                write_iv = %hex_dump(&wi),
+                read_key = %hex_dump(&rk),
+                read_iv = %hex_dump(&ri),
+                srv_ip = %srv_ip_opt.map(|ip| hex_dump(&ip)).unwrap_or_default(),
+                clt_ip = %clt_ip_opt.map(|ip| hex_dump(&ip)).unwrap_or_default(),
+                srv_port = %hex_dump(&server_port_bytes),
+                clt_port = %hex_dump(&client_port_bytes),
+                crypto_ts = %hex_dump(&ts_bytes),
+                nonce_srv = %hex_dump(&srv_nonce),
+                nonce_clt = %hex_dump(&my_nonce),
+                prekey_sha256_client = %hex_dump(&sha256(&prekey_client)),
+                prekey_sha256_server = %hex_dump(&sha256(&prekey_server)),
+                hs_plain = %hex_dump(&hs_frame),
+                proxy_secret_sha256 = %hex_dump(&sha256(&secret)),
+                "ME diag: derived keys and handshake plaintext"
+            );
+        }
+        if diag_level >= 2 {
+            info!(
+                prekey_client = %hex_dump(&prekey_client),
+                prekey_server = %hex_dump(&prekey_server),
+                "ME diag: full prekey buffers"
+            );
+        }
+
+        let (encrypted_hs, mut write_iv) = cbc_encrypt_padded(&wk, &wi, &hs_frame)?;
+        if diag_level >= 1 {
+            info!(
+                hs_cipher = %hex_dump(&encrypted_hs),
+                "ME diag: handshake ciphertext"
+            );
+        }
+        wr.write_all(&encrypted_hs).await.map_err(ProxyError::Io)?;
+        wr.flush().await.map_err(ProxyError::Io)?;
+
+        let deadline = Instant::now() + Duration::from_secs(ME_HANDSHAKE_TIMEOUT_SECS);
+        let mut enc_buf = BytesMut::with_capacity(256);
+        let mut dec_buf = BytesMut::with_capacity(256);
+        let mut read_iv = ri;
+        let mut handshake_ok = false;
+
+        while Instant::now() < deadline && !handshake_ok {
+            let remaining = deadline - Instant::now();
+            let mut tmp = [0u8; 256];
+            let n = match timeout(remaining, rd.read(&mut tmp)).await {
+                Ok(Ok(0)) => {
+                    return Err(ProxyError::Io(std::io::Error::new(
+                        std::io::ErrorKind::UnexpectedEof,
+                        "ME closed during handshake",
+                    )));
+                }
+                Ok(Ok(n)) => n,
+                Ok(Err(e)) => return Err(ProxyError::Io(e)),
+                Err(_) => return Err(ProxyError::TgHandshakeTimeout),
+            };
+
+            enc_buf.extend_from_slice(&tmp[..n]);
+
+            let blocks = enc_buf.len() / 16 * 16;
+            if blocks > 0 {
+                let mut chunk = vec![0u8; blocks];
+                chunk.copy_from_slice(&enc_buf[..blocks]);
+                read_iv = cbc_decrypt_inplace(&rk, &read_iv, &mut chunk)?;
+                dec_buf.extend_from_slice(&chunk);
+                let _ = enc_buf.split_to(blocks);
+            }
+
+            while dec_buf.len() >= 4 {
+                let fl = u32::from_le_bytes(dec_buf[0..4].try_into().unwrap()) as usize;
+
+                if fl == 4 {
+                    let _ = dec_buf.split_to(4);
+                    continue;
+                }
+                if !(12..=(1 << 24)).contains(&fl) {
+                    return Err(ProxyError::InvalidHandshake(format!(
+                        "Bad HS response frame len: {fl}"
+                    )));
+                }
+                if dec_buf.len() < fl {
+                    break;
+                }
+
+                let frame = dec_buf.split_to(fl);
+                let pe = fl - 4;
+                let ec = u32::from_le_bytes(frame[pe..pe + 4].try_into().unwrap());
+                let ac = crate::crypto::crc32(&frame[..pe]);
+                if ec != ac {
+                    return Err(ProxyError::InvalidHandshake(format!(
+                        "HS CRC mismatch: 0x{ec:08x} vs 0x{ac:08x}"
+                    )));
+                }
+
+                let hs_type = u32::from_le_bytes(frame[8..12].try_into().unwrap());
+                if hs_type == RPC_HANDSHAKE_ERROR_U32 {
+                    let err_code = if frame.len() >= 16 {
+                        i32::from_le_bytes(frame[12..16].try_into().unwrap())
+                    } else {
+                        -1
+                    };
+                    return Err(ProxyError::InvalidHandshake(format!(
+                        "ME rejected handshake (error={err_code})"
+                    )));
+                }
+                if hs_type != RPC_HANDSHAKE_U32 {
+                    return Err(ProxyError::InvalidHandshake(format!(
+                        "Expected HANDSHAKE 0x{RPC_HANDSHAKE_U32:08x}, got 0x{hs_type:08x}"
+                    )));
+                }
+
+                handshake_ok = true;
+                break;
+            }
+        }
+
+        if !handshake_ok {
+            return Err(ProxyError::TgHandshakeTimeout);
+        }
+
+        let handshake_ms = hs_start.elapsed().as_secs_f64() * 1000.0;
+        info!(%addr, "RPC handshake OK");
+
+        Ok(HandshakeOutput {
+            rd,
+            wr,
+            read_key: rk,
+            read_iv,
+            write_key: wk,
+            write_iv,
+            handshake_ms,
+        })
+    }
+}
+
+fn hex_dump(data: &[u8]) -> String {
+    const MAX: usize = 64;
+    let mut out = String::with_capacity(data.len() * 2 + 3);
+    for (i, b) in data.iter().take(MAX).enumerate() {
+        if i > 0 {
+            out.push(' ');
+        }
+        out.push_str(&format!("{b:02x}"));
+    }
+    if data.len() > MAX {
+        out.push_str(" …");
+    }
+    out
+}

src/transport/middle_proxy/health.rs

@@ -1,38 +1,90 @@
+use std::collections::{HashMap, HashSet};
 use std::net::SocketAddr;
 use std::sync::Arc;
-use std::time::Duration;
+use std::time::{Duration, Instant};
 
 use tracing::{debug, info, warn};
+use rand::seq::SliceRandom;
 
 use crate::crypto::SecureRandom;
-use crate::protocol::constants::TG_MIDDLE_PROXIES_FLAT_V4;
+use crate::network::IpFamily;
 
 use super::MePool;
 
-pub async fn me_health_monitor(pool: Arc<MePool>, rng: Arc<SecureRandom>, min_connections: usize) {
+pub async fn me_health_monitor(pool: Arc<MePool>, rng: Arc<SecureRandom>, _min_connections: usize) {
+    let mut backoff: HashMap<(i32, IpFamily), u64> = HashMap::new();
+    let mut last_attempt: HashMap<(i32, IpFamily), Instant> = HashMap::new();
     loop {
         tokio::time::sleep(Duration::from_secs(30)).await;
-        let current = pool.connection_count();
+        check_family(IpFamily::V4, &pool, &rng, &mut backoff, &mut last_attempt).await;
-        if current < min_connections {
+        check_family(IpFamily::V6, &pool, &rng, &mut backoff, &mut last_attempt).await;
-            warn!(
+    }
-                current,
+}
-                min = min_connections,
+
-                "ME pool below minimum, reconnecting..."
+async fn check_family(
-            );
+    family: IpFamily,
-            let addrs = TG_MIDDLE_PROXIES_FLAT_V4.clone();
+    pool: &Arc<MePool>,
-            for &(ip, port) in addrs.iter() {
+    rng: &Arc<SecureRandom>,
-                let needed = min_connections.saturating_sub(pool.connection_count());
+    backoff: &mut HashMap<(i32, IpFamily), u64>,
-                if needed == 0 {
+    last_attempt: &mut HashMap<(i32, IpFamily), Instant>,
+) {
+    let enabled = match family {
+        IpFamily::V4 => pool.decision.ipv4_me,
+        IpFamily::V6 => pool.decision.ipv6_me,
+    };
+    if !enabled {
+        return;
+    }
+
+    let map = match family {
+        IpFamily::V4 => pool.proxy_map_v4.read().await.clone(),
+        IpFamily::V6 => pool.proxy_map_v6.read().await.clone(),
+    };
+    let writer_addrs: HashSet<SocketAddr> = pool
+        .writers
+        .read()
+        .await
+        .iter()
+        .map(|w| w.addr)
+        .collect();
+
+    for (dc, addrs) in map.iter() {
+        let dc_addrs: Vec<SocketAddr> = addrs
+            .iter()
+            .map(|(ip, port)| SocketAddr::new(*ip, *port))
+            .collect();
+        let has_coverage = dc_addrs.iter().any(|a| writer_addrs.contains(a));
+        if has_coverage {
+            continue;
+        }
+        let key = (*dc, family);
+        let delay = *backoff.get(&key).unwrap_or(&30);
+        let now = Instant::now();
+        if let Some(last) = last_attempt.get(&key) {
+            if now.duration_since(*last).as_secs() < delay {
+                continue;
+            }
+        }
+        warn!(dc = %dc, delay, ?family, "DC has no ME coverage, reconnecting...");
+        let mut shuffled = dc_addrs.clone();
+        shuffled.shuffle(&mut rand::rng());
+        let mut reconnected = false;
+        for addr in shuffled {
+            match pool.connect_one(addr, rng.as_ref()).await {
+                Ok(()) => {
+                    info!(%addr, dc = %dc, ?family, "ME reconnected for DC coverage");
+                    backoff.insert(key, 30);
+                    last_attempt.insert(key, now);
+                    reconnected = true;
                     break;
                 }
-                for _ in 0..needed {
+                Err(e) => debug!(%addr, dc = %dc, error = %e, ?family, "ME reconnect failed"),
-                    let addr = SocketAddr::new(ip, port);
-                    match pool.connect_one(addr, &rng).await {
-                        Ok(()) => info!(%addr, "ME reconnected"),
-                        Err(e) => debug!(%addr, error = %e, "ME reconnect failed"),
-                    }
             }
         }
+        if !reconnected {
+            let next = (*backoff.get(&key).unwrap_or(&30)).saturating_mul(2).min(300);
+            backoff.insert(key, next);
+            last_attempt.insert(key, now);
         }
     }
 }

src/transport/middle_proxy/mod.rs

@@ -1,21 +1,29 @@
 //! Middle Proxy RPC transport.
 
 mod codec;
+mod handshake;
 mod health;
 mod pool;
 mod pool_nat;
+mod ping;
 mod reader;
 mod registry;
 mod send;
 mod secret;
+mod rotation;
+mod config_updater;
 mod wire;
 
 use bytes::Bytes;
 
 pub use health::me_health_monitor;
+pub use ping::{run_me_ping, format_sample_line, MePingReport, MePingSample, MePingFamily};
 pub use pool::MePool;
+pub use pool_nat::{stun_probe, detect_public_ip};
 pub use registry::ConnRegistry;
 pub use secret::fetch_proxy_secret;
+pub use config_updater::{fetch_proxy_config, me_config_updater};
+pub use rotation::me_rotation_task;
 pub use wire::proto_flags_for_tag;
 
 #[derive(Debug)]

src/transport/middle_proxy/ping.rs

@@ -0,0 +1,173 @@
+use std::collections::HashMap;
+use std::net::{IpAddr, SocketAddr};
+use std::sync::Arc;
+
+use crate::crypto::SecureRandom;
+use crate::error::ProxyError;
+
+use super::MePool;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum MePingFamily {
+    V4,
+    V6,
+}
+
+#[derive(Debug, Clone)]
+pub struct MePingSample {
+    pub dc: i32,
+    pub addr: SocketAddr,
+    pub connect_ms: Option<f64>,
+    pub handshake_ms: Option<f64>,
+    pub error: Option<String>,
+    pub family: MePingFamily,
+}
+
+#[derive(Debug, Clone)]
+pub struct MePingReport {
+    pub dc: i32,
+    pub family: MePingFamily,
+    pub samples: Vec<MePingSample>,
+}
+
+pub fn format_sample_line(sample: &MePingSample) -> String {
+    let sign = if sample.dc >= 0 { "+" } else { "-" };
+    let addr = format!("{}:{}", sample.addr.ip(), sample.addr.port());
+
+    match (sample.connect_ms, sample.handshake_ms.as_ref(), sample.error.as_ref()) {
+        (Some(conn), Some(hs), None) => format!(
+            "     {sign} {addr}\tPing: {:.0} ms / RPC: {:.0} ms / OK",
+            conn, hs
+        ),
+        (Some(conn), None, Some(err)) => format!(
+            "     {sign} {addr}\tPing: {:.0} ms / RPC: FAIL ({err})",
+            conn
+        ),
+        (None, _, Some(err)) => format!("     {sign} {addr}\tPing: FAIL ({err})"),
+        (Some(conn), None, None) => format!("     {sign} {addr}\tPing: {:.0} ms / RPC: FAIL", conn),
+        _ => format!("     {sign} {addr}\tPing: FAIL"),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+
+    fn sample(base: MePingSample) -> MePingSample {
+        base
+    }
+
+    #[test]
+    fn ok_line_contains_both_timings() {
+        let s = sample(MePingSample {
+            dc: 4,
+            addr: SocketAddr::new(IpAddr::V4(Ipv4Addr::new(1, 2, 3, 4)), 8888),
+            connect_ms: Some(12.3),
+            handshake_ms: Some(34.7),
+            error: None,
+            family: MePingFamily::V4,
+        });
+        let line = format_sample_line(&s);
+        assert!(line.contains("Ping: 12 ms"));
+        assert!(line.contains("RPC: 35 ms"));
+        assert!(line.contains("OK"));
+    }
+
+    #[test]
+    fn error_line_mentions_reason() {
+        let s = sample(MePingSample {
+            dc: -5,
+            addr: SocketAddr::new(IpAddr::V4(Ipv4Addr::new(5, 6, 7, 8)), 80),
+            connect_ms: Some(10.0),
+            handshake_ms: None,
+            error: Some("handshake timeout".to_string()),
+            family: MePingFamily::V4,
+        });
+        let line = format_sample_line(&s);
+        assert!(line.contains("- 5.6.7.8:80"));
+        assert!(line.contains("handshake timeout"));
+    }
+}
+
+pub async fn run_me_ping(pool: &Arc<MePool>, rng: &SecureRandom) -> Vec<MePingReport> {
+    let mut reports = Vec::new();
+
+    let v4_map = if pool.decision.ipv4_me {
+        pool.proxy_map_v4.read().await.clone()
+    } else {
+        HashMap::new()
+    };
+    let v6_map = if pool.decision.ipv6_me {
+        pool.proxy_map_v6.read().await.clone()
+    } else {
+        HashMap::new()
+    };
+
+    let mut grouped: Vec<(MePingFamily, i32, Vec<(IpAddr, u16)>)> = Vec::new();
+    for (dc, addrs) in v4_map {
+        grouped.push((MePingFamily::V4, dc, addrs));
+    }
+    for (dc, addrs) in v6_map {
+        grouped.push((MePingFamily::V6, dc, addrs));
+    }
+
+    for (family, dc, addrs) in grouped {
+        let mut samples = Vec::new();
+        for (ip, port) in addrs {
+            let addr = SocketAddr::new(ip, port);
+            let mut connect_ms = None;
+            let mut handshake_ms = None;
+            let mut error = None;
+
+            match pool.connect_tcp(addr).await {
+                Ok((stream, conn_rtt)) => {
+                    connect_ms = Some(conn_rtt);
+                    match pool.handshake_only(stream, addr, rng).await {
+                        Ok(hs) => {
+                            handshake_ms = Some(hs.handshake_ms);
+                            // drop halves to close
+                            drop(hs.rd);
+                            drop(hs.wr);
+                        }
+                        Err(e) => {
+                            error = Some(short_err(&e));
+                        }
+                    }
+                }
+                Err(e) => {
+                    error = Some(short_err(&e));
+                }
+            }
+
+            samples.push(MePingSample {
+                dc,
+                addr,
+                connect_ms,
+                handshake_ms,
+                error,
+                family,
+            });
+        }
+
+        reports.push(MePingReport {
+            dc,
+            family,
+            samples,
+        });
+    }
+
+    reports
+}
+
+fn short_err(err: &ProxyError) -> String {
+    match err {
+        ProxyError::ConnectionTimeout { .. } => "connect timeout".to_string(),
+        ProxyError::TgHandshakeTimeout => "handshake timeout".to_string(),
+        ProxyError::InvalidHandshake(e) => format!("bad handshake: {e}"),
+        ProxyError::Crypto(e) => format!("crypto: {e}"),
+        ProxyError::Proxy(e) => format!("proxy: {e}"),
+        ProxyError::Io(e) => format!("io: {e}"),
+        _ => format!("{err}"),
+    }
+}

src/transport/middle_proxy/pool.rs

@@ -1,45 +1,67 @@
+use std::collections::HashMap;
 use std::net::{IpAddr, SocketAddr};
 use std::sync::Arc;
-use std::sync::OnceLock;
+use std::sync::atomic::{AtomicBool, AtomicI32, AtomicU64, Ordering};
-use std::sync::atomic::AtomicU64;
-use std::time::Duration;
-
 use bytes::BytesMut;
 use rand::Rng;
-use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use rand::seq::SliceRandom;
-use tokio::net::TcpStream;
 use tokio::sync::{Mutex, RwLock};
-use tokio::time::{Instant, timeout};
+use tokio_util::sync::CancellationToken;
 use tracing::{debug, info, warn};
+use std::time::Duration;
 
-use crate::crypto::{SecureRandom, build_middleproxy_prekey, derive_middleproxy_keys, sha256};
+use crate::crypto::SecureRandom;
 use crate::error::{ProxyError, Result};
+use crate::network::probe::NetworkDecision;
+use crate::network::IpFamily;
 use crate::protocol::constants::*;
 
 use super::ConnRegistry;
-use super::codec::{
+use super::registry::{BoundConn, ConnMeta};
-    RpcWriter, build_handshake_payload, build_nonce_payload, build_rpc_frame, cbc_decrypt_inplace,
+use super::codec::RpcWriter;
-    cbc_encrypt_padded, parse_nonce_payload, read_rpc_frame_plaintext,
-};
 use super::reader::reader_loop;
-use super::wire::{IpMaterial, extract_ip_material};
+use super::MeResponse;
 
 const ME_ACTIVE_PING_SECS: u64 = 25;
 const ME_ACTIVE_PING_JITTER_SECS: i64 = 5;
 
+#[derive(Clone)]
+pub struct MeWriter {
+    pub id: u64,
+    pub addr: SocketAddr,
+    pub writer: Arc<Mutex<RpcWriter>>,
+    pub cancel: CancellationToken,
+    pub degraded: Arc<AtomicBool>,
+}
+
 pub struct MePool {
     pub(super) registry: Arc<ConnRegistry>,
-    pub(super) writers: Arc<RwLock<Vec<(SocketAddr, Arc<Mutex<RpcWriter>>)>>> ,
+    pub(super) writers: Arc<RwLock<Vec<MeWriter>>>,
     pub(super) rr: AtomicU64,
+    pub(super) decision: NetworkDecision,
+    pub(super) rng: Arc<SecureRandom>,
     pub(super) proxy_tag: Option<Vec<u8>>,
-    proxy_secret: Vec<u8>,
+    pub(super) proxy_secret: Arc<RwLock<Vec<u8>>>,
     pub(super) nat_ip_cfg: Option<IpAddr>,
-    pub(super) nat_ip_detected: OnceLock<IpAddr>,
+    pub(super) nat_ip_detected: Arc<RwLock<Option<IpAddr>>>,
     pub(super) nat_probe: bool,
     pub(super) nat_stun: Option<String>,
+    pub(super) proxy_map_v4: Arc<RwLock<HashMap<i32, Vec<(IpAddr, u16)>>>>,
+    pub(super) proxy_map_v6: Arc<RwLock<HashMap<i32, Vec<(IpAddr, u16)>>>>,
+    pub(super) default_dc: AtomicI32,
+    pub(super) next_writer_id: AtomicU64,
+    pub(super) ping_tracker: Arc<Mutex<HashMap<i64, (std::time::Instant, u64)>>>,
+    pub(super) rtt_stats: Arc<Mutex<HashMap<u64, (f64, f64)>>>,
+    pub(super) nat_reflection_cache: Arc<Mutex<NatReflectionCache>>,
     pool_size: usize,
 }
 
+#[derive(Debug, Default)]
+pub struct NatReflectionCache {
+    pub v4: Option<(std::time::Instant, std::net::SocketAddr)>,
+    pub v6: Option<(std::time::Instant, std::net::SocketAddr)>,
+}
+
 impl MePool {
     pub fn new(
         proxy_tag: Option<Vec<u8>>,
@@ -47,18 +69,32 @@ impl MePool {
         nat_ip: Option<IpAddr>,
         nat_probe: bool,
         nat_stun: Option<String>,
+        proxy_map_v4: HashMap<i32, Vec<(IpAddr, u16)>>,
+        proxy_map_v6: HashMap<i32, Vec<(IpAddr, u16)>>,
+        default_dc: Option<i32>,
+        decision: NetworkDecision,
+        rng: Arc<SecureRandom>,
     ) -> Arc<Self> {
         Arc::new(Self {
             registry: Arc::new(ConnRegistry::new()),
             writers: Arc::new(RwLock::new(Vec::new())),
             rr: AtomicU64::new(0),
+            decision,
+            rng,
             proxy_tag,
-            proxy_secret,
+            proxy_secret: Arc::new(RwLock::new(proxy_secret)),
             nat_ip_cfg: nat_ip,
-            nat_ip_detected: OnceLock::new(),
+            nat_ip_detected: Arc::new(RwLock::new(None)),
             nat_probe,
             nat_stun,
             pool_size: 2,
+            proxy_map_v4: Arc::new(RwLock::new(proxy_map_v4)),
+            proxy_map_v6: Arc::new(RwLock::new(proxy_map_v6)),
+            default_dc: AtomicI32::new(default_dc.unwrap_or(0)),
+            next_writer_id: AtomicU64::new(1),
+            ping_tracker: Arc::new(Mutex::new(HashMap::new())),
+            rtt_stats: Arc::new(Mutex::new(HashMap::new())),
+            nat_reflection_cache: Arc::new(Mutex::new(NatReflectionCache::default())),
         })
     }
 
@@ -75,44 +111,167 @@ impl MePool {
         &self.registry
     }
 
-    fn writers_arc(&self) -> Arc<RwLock<Vec<(SocketAddr, Arc<Mutex<RpcWriter>>)>>>
+    fn writers_arc(&self) -> Arc<RwLock<Vec<MeWriter>>> {
-    {
         self.writers.clone()
     }
 
-    fn key_selector(&self) -> u32 {
+    pub async fn reconcile_connections(self: &Arc<Self>, rng: &SecureRandom) {
-        if self.proxy_secret.len() >= 4 {
+        use std::collections::HashSet;
-            u32::from_le_bytes([
+        let writers = self.writers.read().await;
-                self.proxy_secret[0],
+        let current: HashSet<SocketAddr> = writers.iter().map(|w| w.addr).collect();
-                self.proxy_secret[1],
+        drop(writers);
-                self.proxy_secret[2],
+
-                self.proxy_secret[3],
+        for family in self.family_order() {
-            ])
+            let map = self.proxy_map_for_family(family).await;
+            for (_dc, addrs) in map.iter() {
+                let dc_addrs: Vec<SocketAddr> = addrs
+                    .iter()
+                    .map(|(ip, port)| SocketAddr::new(*ip, *port))
+                    .collect();
+                if !dc_addrs.iter().any(|a| current.contains(a)) {
+                    let mut shuffled = dc_addrs.clone();
+                    shuffled.shuffle(&mut rand::rng());
+                    for addr in shuffled {
+                        if self.connect_one(addr, rng).await.is_ok() {
+                            break;
+                        }
+                    }
+                }
+            }
+            if !self.decision.effective_multipath && !current.is_empty() {
+                break;
+            }
+        }
+    }
+
+    pub async fn update_proxy_maps(
+        &self,
+        new_v4: HashMap<i32, Vec<(IpAddr, u16)>>,
+        new_v6: Option<HashMap<i32, Vec<(IpAddr, u16)>>>,
+    ) -> bool {
+        let mut changed = false;
+        {
+            let mut guard = self.proxy_map_v4.write().await;
+            if !new_v4.is_empty() && *guard != new_v4 {
+                *guard = new_v4;
+                changed = true;
+            }
+        }
+        if let Some(v6) = new_v6 {
+            let mut guard = self.proxy_map_v6.write().await;
+            if !v6.is_empty() && *guard != v6 {
+                *guard = v6;
+            }
+        }
+        changed
+    }
+
+    pub async fn update_secret(&self, new_secret: Vec<u8>) -> bool {
+        if new_secret.len() < 32 {
+            warn!(len = new_secret.len(), "proxy-secret update ignored (too short)");
+            return false;
+        }
+        let mut guard = self.proxy_secret.write().await;
+        if *guard != new_secret {
+            *guard = new_secret;
+            drop(guard);
+            self.reconnect_all().await;
+            return true;
+        }
+        false
+    }
+
+    pub async fn reconnect_all(&self) {
+        // Graceful: do not drop all at once. New connections will use updated secret.
+        // Existing writers remain until health monitor replaces them.
+        // No-op here to avoid total outage.
+    }
+
+    pub(super) async fn key_selector(&self) -> u32 {
+        let secret = self.proxy_secret.read().await;
+        if secret.len() >= 4 {
+            u32::from_le_bytes([secret[0], secret[1], secret[2], secret[3]])
         } else {
             0
         }
     }
 
-    pub async fn init(self: &Arc<Self>, pool_size: usize, rng: &SecureRandom) -> Result<()> {
+    pub(super) fn family_order(&self) -> Vec<IpFamily> {
-        let addrs = &*TG_MIDDLE_PROXIES_FLAT_V4;
+        let mut order = Vec::new();
-        let ks = self.key_selector();
+        if self.decision.prefer_ipv6() {
+            if self.decision.ipv6_me {
+                order.push(IpFamily::V6);
+            }
+            if self.decision.ipv4_me {
+                order.push(IpFamily::V4);
+            }
+        } else {
+            if self.decision.ipv4_me {
+                order.push(IpFamily::V4);
+            }
+            if self.decision.ipv6_me {
+                order.push(IpFamily::V6);
+            }
+        }
+        order
+    }
+
+    async fn proxy_map_for_family(&self, family: IpFamily) -> HashMap<i32, Vec<(IpAddr, u16)>> {
+        match family {
+            IpFamily::V4 => self.proxy_map_v4.read().await.clone(),
+            IpFamily::V6 => self.proxy_map_v6.read().await.clone(),
+        }
+    }
+
+    pub async fn init(self: &Arc<Self>, pool_size: usize, rng: &Arc<SecureRandom>) -> Result<()> {
+        let family_order = self.family_order();
+        let ks = self.key_selector().await;
         info!(
-            me_servers = addrs.len(),
+            me_servers = self.proxy_map_v4.read().await.len(),
             pool_size,
             key_selector = format_args!("0x{ks:08x}"),
-            secret_len = self.proxy_secret.len(),
+            secret_len = self.proxy_secret.read().await.len(),
             "Initializing ME pool"
         );
 
-        for &(ip, port) in addrs.iter() {
+        for family in family_order {
-            for i in 0..pool_size {
+            let map = self.proxy_map_for_family(family).await;
-                let addr = SocketAddr::new(ip, port);
+            let dc_addrs: Vec<(i32, Vec<(IpAddr, u16)>)> = map
-                match self.connect_one(addr, rng).await {
+                .iter()
-                    Ok(()) => info!(%addr, idx = i, "ME connected"),
+                .map(|(dc, addrs)| (*dc, addrs.clone()))
-                    Err(e) => warn!(%addr, idx = i, error = %e, "ME connect failed"),
+                .collect();
+
+            // Ensure at least one connection per DC; run DCs in parallel.
+            let mut join = tokio::task::JoinSet::new();
+            for (dc, addrs) in dc_addrs.iter().cloned() {
+                if addrs.is_empty() {
+                    continue;
+                }
+                let pool = Arc::clone(self);
+                let rng_clone = Arc::clone(rng);
+                join.spawn(async move {
+                    pool.connect_primary_for_dc(dc, addrs, rng_clone).await;
+                });
+            }
+            while let Some(_res) = join.join_next().await {}
+
+            // Additional connections up to pool_size total (round-robin across DCs)
+            for (dc, addrs) in dc_addrs.iter() {
+                for (ip, port) in addrs {
+                    if self.connection_count() >= pool_size {
+                        break;
+                    }
+                    let addr = SocketAddr::new(*ip, *port);
+                    if let Err(e) = self.connect_one(addr, rng.as_ref()).await {
+                        debug!(%addr, dc = %dc, error = %e, "Extra ME connect failed");
                     }
                 }
-            if self.writers.read().await.len() >= pool_size {
+                if self.connection_count() >= pool_size {
+                    break;
+                }
+            }
+
+            if !self.decision.effective_multipath && self.connection_count() > 0 {
                 break;
             }
         }
@@ -123,356 +282,98 @@ impl MePool {
         Ok(())
     }
 
-    pub(crate) async fn connect_one(
+    pub(crate) async fn connect_one(self: &Arc<Self>, addr: SocketAddr, rng: &SecureRandom) -> Result<()> {
-        self: &Arc<Self>,
+        let secret_len = self.proxy_secret.read().await.len();
-        addr: SocketAddr,
+        if secret_len < 32 {
-        rng: &SecureRandom,
+            return Err(ProxyError::Proxy("proxy-secret too short for ME auth".into()));
-    ) -> Result<()> {
-        let secret = &self.proxy_secret;
-        if secret.len() < 32 {
-            return Err(ProxyError::Proxy(
-                "proxy-secret too short for ME auth".into(),
-            ));
         }
 
-        let stream = timeout(
+        let (stream, _connect_ms) = self.connect_tcp(addr).await?;
-            Duration::from_secs(ME_CONNECT_TIMEOUT_SECS),
+        let hs = self.handshake_only(stream, addr, rng).await?;
-            TcpStream::connect(addr),
-        )
-        .await
-        .map_err(|_| ProxyError::ConnectionTimeout {
-            addr: addr.to_string(),
-        })?
-        .map_err(ProxyError::Io)?;
-        stream.set_nodelay(true).ok();
-
-        let local_addr = stream.local_addr().map_err(ProxyError::Io)?;
-        let peer_addr = stream.peer_addr().map_err(ProxyError::Io)?;
-        let _ = self.maybe_detect_nat_ip(local_addr.ip()).await;
-        let reflected = if self.nat_probe {
-            self.maybe_reflect_public_addr().await
-        } else {
-            None
-        };
-        let local_addr_nat = self.translate_our_addr_with_reflection(local_addr, reflected);
-        let peer_addr_nat =
-            SocketAddr::new(self.translate_ip_for_nat(peer_addr.ip()), peer_addr.port());
-        let (mut rd, mut wr) = tokio::io::split(stream);
-
-        let my_nonce: [u8; 16] = rng.bytes(16).try_into().unwrap();
-        let crypto_ts = std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .unwrap_or_default()
-            .as_secs() as u32;
-
-        let ks = self.key_selector();
-        let nonce_payload = build_nonce_payload(ks, crypto_ts, &my_nonce);
-        let nonce_frame = build_rpc_frame(-2, &nonce_payload);
-        let dump = hex_dump(&nonce_frame[..nonce_frame.len().min(44)]);
-        info!(
-            key_selector = format_args!("0x{ks:08x}"),
-            crypto_ts,
-            frame_len = nonce_frame.len(),
-            nonce_frame_hex = %dump,
-            "Sending ME nonce frame"
-        );
-        wr.write_all(&nonce_frame).await.map_err(ProxyError::Io)?;
-        wr.flush().await.map_err(ProxyError::Io)?;
-
-        let (srv_seq, srv_nonce_payload) = timeout(
-            Duration::from_secs(ME_HANDSHAKE_TIMEOUT_SECS),
-            read_rpc_frame_plaintext(&mut rd),
-        )
-        .await
-        .map_err(|_| ProxyError::TgHandshakeTimeout)??;
-
-        if srv_seq != -2 {
-            return Err(ProxyError::InvalidHandshake(format!(
-                "Expected seq=-2, got {srv_seq}"
-            )));
-        }
-
-        let (srv_key_select, schema, srv_ts, srv_nonce) = parse_nonce_payload(&srv_nonce_payload)?;
-        if schema != RPC_CRYPTO_AES_U32 {
-            warn!(schema = format_args!("0x{schema:08x}"), "Unsupported ME crypto schema");
-            return Err(ProxyError::InvalidHandshake(format!(
-                "Unsupported crypto schema: 0x{schema:x}"
-            )));
-        }
-
-        if srv_key_select != ks {
-            return Err(ProxyError::InvalidHandshake(format!(
-                "Server key_select 0x{srv_key_select:08x} != client 0x{ks:08x}"
-            )));
-        }
-
-        let skew = crypto_ts.abs_diff(srv_ts);
-        if skew > 30 {
-            return Err(ProxyError::InvalidHandshake(format!(
-                "nonce crypto_ts skew too large: client={crypto_ts}, server={srv_ts}, skew={skew}s"
-            )));
-        }
-
-        info!(
-            %local_addr,
-            %local_addr_nat,
-            reflected_ip = reflected.map(|r| r.ip()).as_ref().map(ToString::to_string),
-            %peer_addr,
-            %peer_addr_nat,
-            key_selector = format_args!("0x{ks:08x}"),
-            crypto_schema = format_args!("0x{schema:08x}"),
-            skew_secs = skew,
-            "ME key derivation parameters"
-        );
-
-        let ts_bytes = crypto_ts.to_le_bytes();
-        let server_port_bytes = peer_addr_nat.port().to_le_bytes();
-        let client_port_bytes = local_addr_nat.port().to_le_bytes();
-
-        let server_ip = extract_ip_material(peer_addr_nat);
-        let client_ip = extract_ip_material(local_addr_nat);
-
-        let (srv_ip_opt, clt_ip_opt, clt_v6_opt, srv_v6_opt, hs_our_ip, hs_peer_ip) =
-            match (server_ip, client_ip) {
-                (IpMaterial::V4(srv), IpMaterial::V4(clt)) => {
-                    (Some(srv), Some(clt), None, None, clt, srv)
-                }
-                (IpMaterial::V6(srv), IpMaterial::V6(clt)) => {
-                    let zero = [0u8; 4];
-                    (None, None, Some(clt), Some(srv), zero, zero)
-                }
-                _ => {
-                    return Err(ProxyError::InvalidHandshake(
-                        "mixed IPv4/IPv6 endpoints are not supported for ME key derivation"
-                            .to_string(),
-                    ));
-                }
-            };
-
-        let diag_level: u8 = std::env::var("ME_DIAG")
-            .ok()
-            .and_then(|v| v.parse().ok())
-            .unwrap_or(0);
-
-        let prekey_client = build_middleproxy_prekey(
-            &srv_nonce,
-            &my_nonce,
-            &ts_bytes,
-            srv_ip_opt.as_ref().map(|x| &x[..]),
-            &client_port_bytes,
-            b"CLIENT",
-            clt_ip_opt.as_ref().map(|x| &x[..]),
-            &server_port_bytes,
-            secret,
-            clt_v6_opt.as_ref(),
-            srv_v6_opt.as_ref(),
-        );
-        let prekey_server = build_middleproxy_prekey(
-            &srv_nonce,
-            &my_nonce,
-            &ts_bytes,
-            srv_ip_opt.as_ref().map(|x| &x[..]),
-            &client_port_bytes,
-            b"SERVER",
-            clt_ip_opt.as_ref().map(|x| &x[..]),
-            &server_port_bytes,
-            secret,
-            clt_v6_opt.as_ref(),
-            srv_v6_opt.as_ref(),
-        );
-
-        let (wk, wi) = derive_middleproxy_keys(
-            &srv_nonce,
-            &my_nonce,
-            &ts_bytes,
-            srv_ip_opt.as_ref().map(|x| &x[..]),
-            &client_port_bytes,
-            b"CLIENT",
-            clt_ip_opt.as_ref().map(|x| &x[..]),
-            &server_port_bytes,
-            secret,
-            clt_v6_opt.as_ref(),
-            srv_v6_opt.as_ref(),
-        );
-        let (rk, ri) = derive_middleproxy_keys(
-            &srv_nonce,
-            &my_nonce,
-            &ts_bytes,
-            srv_ip_opt.as_ref().map(|x| &x[..]),
-            &client_port_bytes,
-            b"SERVER",
-            clt_ip_opt.as_ref().map(|x| &x[..]),
-            &server_port_bytes,
-            secret,
-            clt_v6_opt.as_ref(),
-            srv_v6_opt.as_ref(),
-        );
-
-        let hs_payload =
-            build_handshake_payload(hs_our_ip, local_addr.port(), hs_peer_ip, peer_addr.port());
-        let hs_frame = build_rpc_frame(-1, &hs_payload);
-        if diag_level >= 1 {
-            info!(
-                write_key = %hex_dump(&wk),
-                write_iv = %hex_dump(&wi),
-                read_key = %hex_dump(&rk),
-                read_iv = %hex_dump(&ri),
-                srv_ip = %srv_ip_opt.map(|ip| hex_dump(&ip)).unwrap_or_default(),
-                clt_ip = %clt_ip_opt.map(|ip| hex_dump(&ip)).unwrap_or_default(),
-                srv_port = %hex_dump(&server_port_bytes),
-                clt_port = %hex_dump(&client_port_bytes),
-                crypto_ts = %hex_dump(&ts_bytes),
-                nonce_srv = %hex_dump(&srv_nonce),
-                nonce_clt = %hex_dump(&my_nonce),
-                prekey_sha256_client = %hex_dump(&sha256(&prekey_client)),
-                prekey_sha256_server = %hex_dump(&sha256(&prekey_server)),
-                hs_plain = %hex_dump(&hs_frame),
-                proxy_secret_sha256 = %hex_dump(&sha256(secret)),
-                "ME diag: derived keys and handshake plaintext"
-            );
-        }
-        if diag_level >= 2 {
-            info!(
-                prekey_client = %hex_dump(&prekey_client),
-                prekey_server = %hex_dump(&prekey_server),
-                "ME diag: full prekey buffers"
-            );
-        }
-
-        let (encrypted_hs, write_iv) = cbc_encrypt_padded(&wk, &wi, &hs_frame)?;
-        if diag_level >= 1 {
-            info!(
-                hs_cipher = %hex_dump(&encrypted_hs),
-                "ME diag: handshake ciphertext"
-            );
-        }
-        wr.write_all(&encrypted_hs).await.map_err(ProxyError::Io)?;
-        wr.flush().await.map_err(ProxyError::Io)?;
-
-        let deadline = Instant::now() + Duration::from_secs(ME_HANDSHAKE_TIMEOUT_SECS);
-        let mut enc_buf = BytesMut::with_capacity(256);
-        let mut dec_buf = BytesMut::with_capacity(256);
-        let mut read_iv = ri;
-        let mut handshake_ok = false;
-
-        while Instant::now() < deadline && !handshake_ok {
-            let remaining = deadline - Instant::now();
-            let mut tmp = [0u8; 256];
-            let n = match timeout(remaining, rd.read(&mut tmp)).await {
-                Ok(Ok(0)) => {
-                    return Err(ProxyError::Io(std::io::Error::new(
-                        std::io::ErrorKind::UnexpectedEof,
-                        "ME closed during handshake",
-                    )));
-                }
-                Ok(Ok(n)) => n,
-                Ok(Err(e)) => return Err(ProxyError::Io(e)),
-                Err(_) => return Err(ProxyError::TgHandshakeTimeout),
-            };
-
-            enc_buf.extend_from_slice(&tmp[..n]);
-
-            let blocks = enc_buf.len() / 16 * 16;
-            if blocks > 0 {
-                let mut chunk = vec![0u8; blocks];
-                chunk.copy_from_slice(&enc_buf[..blocks]);
-                read_iv = cbc_decrypt_inplace(&rk, &read_iv, &mut chunk)?;
-                dec_buf.extend_from_slice(&chunk);
-                let _ = enc_buf.split_to(blocks);
-            }
-
-            while dec_buf.len() >= 4 {
-                let fl = u32::from_le_bytes(dec_buf[0..4].try_into().unwrap()) as usize;
-
-                if fl == 4 {
-                    let _ = dec_buf.split_to(4);
-                    continue;
-                }
-                if !(12..=(1 << 24)).contains(&fl) {
-                    return Err(ProxyError::InvalidHandshake(format!(
-                        "Bad HS response frame len: {fl}"
-                    )));
-                }
-                if dec_buf.len() < fl {
-                    break;
-                }
-
-                let frame = dec_buf.split_to(fl);
-                let pe = fl - 4;
-                let ec = u32::from_le_bytes(frame[pe..pe + 4].try_into().unwrap());
-                let ac = crate::crypto::crc32(&frame[..pe]);
-                if ec != ac {
-                    return Err(ProxyError::InvalidHandshake(format!(
-                        "HS CRC mismatch: 0x{ec:08x} vs 0x{ac:08x}"
-                    )));
-                }
-
-                let hs_type = u32::from_le_bytes(frame[8..12].try_into().unwrap());
-                if hs_type == RPC_HANDSHAKE_ERROR_U32 {
-                    let err_code = if frame.len() >= 16 {
-                        i32::from_le_bytes(frame[12..16].try_into().unwrap())
-                    } else {
-                        -1
-                    };
-                    return Err(ProxyError::InvalidHandshake(format!(
-                        "ME rejected handshake (error={err_code})"
-                    )));
-                }
-                if hs_type != RPC_HANDSHAKE_U32 {
-                    return Err(ProxyError::InvalidHandshake(format!(
-                        "Expected HANDSHAKE 0x{RPC_HANDSHAKE_U32:08x}, got 0x{hs_type:08x}"
-                    )));
-                }
-
-                handshake_ok = true;
-                break;
-            }
-        }
-
-        if !handshake_ok {
-            return Err(ProxyError::TgHandshakeTimeout);
-        }
-
-        info!(%addr, "RPC handshake OK");
 
+        let writer_id = self.next_writer_id.fetch_add(1, Ordering::Relaxed);
+        let cancel = CancellationToken::new();
+        let degraded = Arc::new(AtomicBool::new(false));
         let rpc_w = Arc::new(Mutex::new(RpcWriter {
-            writer: wr,
+            writer: hs.wr,
-            key: wk,
+            key: hs.write_key,
-            iv: write_iv,
+            iv: hs.write_iv,
             seq_no: 0,
         }));
-        self.writers.write().await.push((addr, rpc_w.clone()));
+        let writer = MeWriter {
+            id: writer_id,
+            addr,
+            writer: rpc_w.clone(),
+            cancel: cancel.clone(),
+            degraded: degraded.clone(),
+        };
+        self.writers.write().await.push(writer.clone());
 
         let reg = self.registry.clone();
-        let w_pong = rpc_w.clone();
+        let writers_arc = self.writers_arc();
-        let w_pool = self.writers_arc();
+        let ping_tracker = self.ping_tracker.clone();
-        let w_ping = rpc_w.clone();
+        let rtt_stats = self.rtt_stats.clone();
-        let w_pool_ping = self.writers_arc();
+        let pool = Arc::downgrade(self);
+        let cancel_ping = cancel.clone();
+        let rpc_w_ping = rpc_w.clone();
+        let ping_tracker_ping = ping_tracker.clone();
+
         tokio::spawn(async move {
-            if let Err(e) =
+            let cancel_reader = cancel.clone();
-                reader_loop(rd, rk, read_iv, reg, enc_buf, dec_buf, w_pong.clone()).await
+            let res = reader_loop(
-            {
+                hs.rd,
+                hs.read_key,
+                hs.read_iv,
+                reg.clone(),
+                BytesMut::new(),
+                BytesMut::new(),
+                rpc_w.clone(),
+                ping_tracker.clone(),
+                rtt_stats.clone(),
+                writer_id,
+                degraded.clone(),
+                cancel_reader.clone(),
+            )
+            .await;
+            if let Some(pool) = pool.upgrade() {
+                pool.remove_writer_and_reroute(writer_id).await;
+            }
+            if let Err(e) = res {
                 warn!(error = %e, "ME reader ended");
             }
-            let mut ws = w_pool.write().await;
+            let mut ws = writers_arc.write().await;
-            ws.retain(|(_, w)| !Arc::ptr_eq(w, &w_pong));
+            ws.retain(|w| w.id != writer_id);
             info!(remaining = ws.len(), "Dead ME writer removed from pool");
         });
+
+        let pool_ping = Arc::downgrade(self);
         tokio::spawn(async move {
             let mut ping_id: i64 = rand::random::<i64>();
             loop {
                 let jitter = rand::rng()
                     .random_range(-ME_ACTIVE_PING_JITTER_SECS..=ME_ACTIVE_PING_JITTER_SECS);
                 let wait = (ME_ACTIVE_PING_SECS as i64 + jitter).max(5) as u64;
-                tokio::time::sleep(Duration::from_secs(wait)).await;
+                tokio::select! {
+                    _ = cancel_ping.cancelled() => {
+                        break;
+                    }
+                    _ = tokio::time::sleep(Duration::from_secs(wait)) => {}
+                }
+                let sent_id = ping_id;
                 let mut p = Vec::with_capacity(12);
                 p.extend_from_slice(&RPC_PING_U32.to_le_bytes());
-                p.extend_from_slice(&ping_id.to_le_bytes());
+                p.extend_from_slice(&sent_id.to_le_bytes());
+                {
+                    let mut tracker = ping_tracker_ping.lock().await;
+                    tracker.insert(sent_id, (std::time::Instant::now(), writer_id));
+                }
                 ping_id = ping_id.wrapping_add(1);
-                if let Err(e) = w_ping.lock().await.send(&p).await {
+                if let Err(e) = rpc_w_ping.lock().await.send(&p).await {
                     debug!(error = %e, "Active ME ping failed, removing dead writer");
-                    let mut ws = w_pool_ping.write().await;
+                    cancel_ping.cancel();
-                    ws.retain(|(_, w)| !Arc::ptr_eq(w, &w_ping));
+                    if let Some(pool) = pool_ping.upgrade() {
+                        pool.remove_writer_and_reroute(writer_id).await;
+                    }
                     break;
                 }
             }
@@ -481,6 +382,124 @@ impl MePool {
         Ok(())
     }
 
+    async fn connect_primary_for_dc(
+        self: Arc<Self>,
+        dc: i32,
+        mut addrs: Vec<(IpAddr, u16)>,
+        rng: Arc<SecureRandom>,
+    ) {
+        if addrs.is_empty() {
+            return;
+        }
+        addrs.shuffle(&mut rand::rng());
+        for (ip, port) in addrs {
+            let addr = SocketAddr::new(ip, port);
+            match self.connect_one(addr, rng.as_ref()).await {
+                Ok(()) => {
+                    info!(%addr, dc = %dc, "ME connected");
+                    return;
+                }
+                Err(e) => warn!(%addr, dc = %dc, error = %e, "ME connect failed, trying next"),
+            }
+        }
+        warn!(dc = %dc, "All ME servers for DC failed at init");
+    }
+
+    pub(crate) async fn remove_writer_and_reroute(&self, writer_id: u64) {
+        let mut queue = self.remove_writer_only(writer_id).await;
+        while let Some(bound) = queue.pop() {
+            if !self.reroute_conn(&bound, &mut queue).await {
+                let _ = self.registry.route(bound.conn_id, super::MeResponse::Close).await;
+            }
+        }
+    }
+
+    async fn remove_writer_only(&self, writer_id: u64) -> Vec<BoundConn> {
+        {
+            let mut ws = self.writers.write().await;
+            if let Some(pos) = ws.iter().position(|w| w.id == writer_id) {
+                let w = ws.remove(pos);
+                w.cancel.cancel();
+            }
+        }
+        self.registry.writer_lost(writer_id).await
+    }
+
+    async fn reroute_conn(&self, bound: &BoundConn, backlog: &mut Vec<BoundConn>) -> bool {
+        let payload = super::wire::build_proxy_req_payload(
+            bound.conn_id,
+            bound.meta.client_addr,
+            bound.meta.our_addr,
+            &[],
+            self.proxy_tag.as_deref(),
+            bound.meta.proto_flags,
+        );
+
+        let mut attempts = 0;
+        loop {
+            let writers_snapshot = {
+                let ws = self.writers.read().await;
+                if ws.is_empty() {
+                    return false;
+                }
+                ws.clone()
+            };
+            let mut candidates = self.candidate_indices_for_dc(&writers_snapshot, bound.meta.target_dc).await;
+            if candidates.is_empty() {
+                return false;
+            }
+            candidates.sort_by_key(|idx| {
+                writers_snapshot[*idx]
+                    .degraded
+                    .load(Ordering::Relaxed)
+                    .then_some(1usize)
+                    .unwrap_or(0)
+            });
+            let start = self.rr.fetch_add(1, Ordering::Relaxed) as usize % candidates.len();
+
+            for offset in 0..candidates.len() {
+                let idx = candidates[(start + offset) % candidates.len()];
+                let w = &writers_snapshot[idx];
+                if let Ok(mut guard) = w.writer.try_lock() {
+                    let send_res = guard.send(&payload).await;
+                    drop(guard);
+                    match send_res {
+                        Ok(()) => {
+                            self.registry
+                                .bind_writer(bound.conn_id, w.id, w.writer.clone(), bound.meta.clone())
+                                .await;
+                            return true;
+                        }
+                        Err(e) => {
+                            warn!(error = %e, writer_id = w.id, "ME reroute send failed");
+                            backlog.extend(self.remove_writer_only(w.id).await);
+                        }
+                    }
+                    continue;
+                }
+            }
+
+            let w = writers_snapshot[candidates[start]].clone();
+            match w.writer.lock().await.send(&payload).await {
+                Ok(()) => {
+                    self.registry
+                        .bind_writer(bound.conn_id, w.id, w.writer.clone(), bound.meta.clone())
+                        .await;
+                    return true;
+                }
+                Err(e) => {
+                    warn!(error = %e, writer_id = w.id, "ME reroute send failed (blocking)");
+                    backlog.extend(self.remove_writer_only(w.id).await);
+                }
+            }
+
+            attempts += 1;
+            if attempts > 3 {
+                return false;
+            }
+        }
+    }
+
 }
 
 fn hex_dump(data: &[u8]) -> String {

src/transport/middle_proxy/pool_nat.rs

@@ -1,16 +1,28 @@
 use std::net::{IpAddr, Ipv4Addr};
+use std::time::Duration;
 
 use tracing::{info, warn};
 
 use crate::error::{ProxyError, Result};
+use crate::network::probe::is_bogon;
+use crate::network::stun::{stun_probe_dual, IpFamily, StunProbeResult};
 
 use super::MePool;
+use std::time::Instant;
+pub async fn stun_probe(stun_addr: Option<String>) -> Result<crate::network::stun::DualStunResult> {
+    let stun_addr = stun_addr.unwrap_or_else(|| "stun.l.google.com:19302".to_string());
+    stun_probe_dual(&stun_addr).await
+}
+
+pub async fn detect_public_ip() -> Option<IpAddr> {
+    fetch_public_ipv4_with_retry().await.ok().flatten().map(IpAddr::V4)
+}
 
 impl MePool {
     pub(super) fn translate_ip_for_nat(&self, ip: IpAddr) -> IpAddr {
         let nat_ip = self
             .nat_ip_cfg
-            .or_else(|| self.nat_ip_detected.get().copied());
+            .or_else(|| self.nat_ip_detected.try_read().ok().and_then(|g| (*g).clone()));
 
         let Some(nat_ip) = nat_ip else {
             return ip;
@@ -18,7 +30,7 @@ impl MePool {
 
         match (ip, nat_ip) {
             (IpAddr::V4(src), IpAddr::V4(dst))
-                if is_privateish(IpAddr::V4(src))
+                if is_bogon(IpAddr::V4(src))
                     || src.is_loopback()
                     || src.is_unspecified() =>
             {
@@ -38,7 +50,7 @@ impl MePool {
     ) -> std::net::SocketAddr {
         let ip = if let Some(r) = reflected {
             // Use reflected IP (not port) only when local address is non-public.
-            if is_privateish(addr.ip()) || addr.ip().is_loopback() || addr.ip().is_unspecified() {
+            if is_bogon(addr.ip()) || addr.ip().is_loopback() || addr.ip().is_unspecified() {
                 r.ip()
             } else {
                 self.translate_ip_for_nat(addr.ip())
@@ -56,17 +68,20 @@ impl MePool {
             return self.nat_ip_cfg;
         }
 
-        if !(is_privateish(local_ip) || local_ip.is_loopback() || local_ip.is_unspecified()) {
+        if !(is_bogon(local_ip) || local_ip.is_loopback() || local_ip.is_unspecified()) {
             return None;
         }
 
-        if let Some(ip) = self.nat_ip_detected.get().copied() {
+        if let Some(ip) = self.nat_ip_detected.read().await.clone() {
             return Some(ip);
         }
 
-        match fetch_public_ipv4().await {
+        match fetch_public_ipv4_with_retry().await {
             Ok(Some(ip)) => {
-                let _ = self.nat_ip_detected.set(IpAddr::V4(ip));
+                {
+                    let mut guard = self.nat_ip_detected.write().await;
+                    *guard = Some(IpAddr::V4(ip));
+                }
                 info!(public_ip = %ip, "Auto-detected public IP for NAT translation");
                 Some(IpAddr::V4(ip))
             }
@@ -78,17 +93,46 @@ impl MePool {
         }
     }
 
-    pub(super) async fn maybe_reflect_public_addr(&self) -> Option<std::net::SocketAddr> {
+    pub(super) async fn maybe_reflect_public_addr(
+        &self,
+        family: IpFamily,
+    ) -> Option<std::net::SocketAddr> {
+        const STUN_CACHE_TTL: Duration = Duration::from_secs(600);
+        if let Ok(mut cache) = self.nat_reflection_cache.try_lock() {
+            let slot = match family {
+                IpFamily::V4 => &mut cache.v4,
+                IpFamily::V6 => &mut cache.v6,
+            };
+            if let Some((ts, addr)) = slot {
+                if ts.elapsed() < STUN_CACHE_TTL {
+                    return Some(*addr);
+                }
+            }
+        }
+
         let stun_addr = self
             .nat_stun
             .clone()
             .unwrap_or_else(|| "stun.l.google.com:19302".to_string());
-        match fetch_stun_binding(&stun_addr).await {
+        match stun_probe_dual(&stun_addr).await {
-            Ok(sa) => {
+            Ok(res) => {
-                if let Some(sa) = sa {
+                let picked: Option<StunProbeResult> = match family {
-                    info!(%sa, "NAT probe: reflected address");
+                    IpFamily::V4 => res.v4,
+                    IpFamily::V6 => res.v6,
+                };
+                if let Some(result) = picked {
+                    info!(local = %result.local_addr, reflected = %result.reflected_addr, family = ?family, "NAT probe: reflected address");
+                    if let Ok(mut cache) = self.nat_reflection_cache.try_lock() {
+                        let slot = match family {
+                            IpFamily::V4 => &mut cache.v4,
+                            IpFamily::V6 => &mut cache.v6,
+                        };
+                        *slot = Some((Instant::now(), result.reflected_addr));
+                    }
+                    Some(result.reflected_addr)
+                } else {
+                    None
                 }
-                sa
             }
             Err(e) => {
                 warn!(error = %e, "NAT probe failed");
@@ -98,8 +142,22 @@ impl MePool {
     }
 }
 
-async fn fetch_public_ipv4() -> Result<Option<Ipv4Addr>> {
+async fn fetch_public_ipv4_with_retry() -> Result<Option<Ipv4Addr>> {
-    let res = reqwest::get("https://checkip.amazonaws.com").await.map_err(|e| {
+    let providers = [
+        "https://checkip.amazonaws.com",
+        "http://v4.ident.me",
+        "http://ipv4.icanhazip.com",
+    ];
+    for url in providers {
+        if let Ok(Some(ip)) = fetch_public_ipv4_once(url).await {
+            return Ok(Some(ip));
+        }
+    }
+    Ok(None)
+}
+
+async fn fetch_public_ipv4_once(url: &str) -> Result<Option<Ipv4Addr>> {
+    let res = reqwest::get(url).await.map_err(|e| {
         ProxyError::Proxy(format!("public IP detection request failed: {e}"))
     })?;
 
@@ -110,91 +168,3 @@ async fn fetch_public_ipv4() -> Result<Option<Ipv4Addr>> {
     let ip = text.trim().parse().ok();
     Ok(ip)
 }
-
-async fn fetch_stun_binding(stun_addr: &str) -> Result<Option<std::net::SocketAddr>> {
-    use rand::RngCore;
-    use tokio::net::UdpSocket;
-
-    let socket = UdpSocket::bind("0.0.0.0:0")
-        .await
-        .map_err(|e| ProxyError::Proxy(format!("STUN bind failed: {e}")))?;
-    socket
-        .connect(stun_addr)
-        .await
-        .map_err(|e| ProxyError::Proxy(format!("STUN connect failed: {e}")))?;
-
-    // Build minimal Binding Request.
-    let mut req = vec![0u8; 20];
-    req[0..2].copy_from_slice(&0x0001u16.to_be_bytes()); // Binding Request
-    req[2..4].copy_from_slice(&0u16.to_be_bytes()); // length
-    req[4..8].copy_from_slice(&0x2112A442u32.to_be_bytes()); // magic cookie
-    rand::thread_rng().fill_bytes(&mut req[8..20]);
-
-    socket
-        .send(&req)
-        .await
-        .map_err(|e| ProxyError::Proxy(format!("STUN send failed: {e}")))?;
-
-    let mut buf = [0u8; 128];
-    let n = socket
-        .recv(&mut buf)
-        .await
-        .map_err(|e| ProxyError::Proxy(format!("STUN recv failed: {e}")))?;
-    if n < 20 {
-        return Ok(None);
-    }
-
-    // Parse attributes.
-    let mut idx = 20;
-    while idx + 4 <= n {
-        let atype = u16::from_be_bytes(buf[idx..idx + 2].try_into().unwrap());
-        let alen = u16::from_be_bytes(buf[idx + 2..idx + 4].try_into().unwrap()) as usize;
-        idx += 4;
-        if idx + alen > n {
-            break;
-        }
-        match atype {
-            0x0020 /* XOR-MAPPED-ADDRESS */ | 0x0001 /* MAPPED-ADDRESS */ => {
-                if alen < 8 {
-                    break;
-                }
-                let family = buf[idx + 1];
-                if family != 0x01 {
-                    // only IPv4 supported here
-                    break;
-                }
-                let port_bytes = [buf[idx + 2], buf[idx + 3]];
-                let ip_bytes = [buf[idx + 4], buf[idx + 5], buf[idx + 6], buf[idx + 7]];
-
-                let (port, ip) = if atype == 0x0020 {
-                    let magic = 0x2112A442u32.to_be_bytes();
-                    let port = u16::from_be_bytes(port_bytes) ^ ((magic[0] as u16) << 8 | magic[1] as u16);
-                    let ip = [
-                        ip_bytes[0] ^ magic[0],
-                        ip_bytes[1] ^ magic[1],
-                        ip_bytes[2] ^ magic[2],
-                        ip_bytes[3] ^ magic[3],
-                    ];
-                    (port, ip)
-                } else {
-                    (u16::from_be_bytes(port_bytes), ip_bytes)
-                };
-                return Ok(Some(std::net::SocketAddr::new(
-                    IpAddr::V4(Ipv4Addr::new(ip[0], ip[1], ip[2], ip[3])),
-                    port,
-                )));
-            }
-            _ => {}
-        }
-        idx += (alen + 3) & !3; // 4-byte alignment
-    }
-
-    Ok(None)
-}
-
-fn is_privateish(ip: IpAddr) -> bool {
-    match ip {
-        IpAddr::V4(v4) => v4.is_private() || v4.is_link_local(),
-        IpAddr::V6(v6) => v6.is_unique_local(),
-    }
-}

src/transport/middle_proxy/reader.rs

@@ -1,9 +1,13 @@
+use std::collections::HashMap;
 use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::time::Instant;
 
 use bytes::{Bytes, BytesMut};
 use tokio::io::AsyncReadExt;
 use tokio::net::TcpStream;
 use tokio::sync::Mutex;
+use tokio_util::sync::CancellationToken;
 use tracing::{debug, trace, warn};
 
 use crate::crypto::{AesCbc, crc32};
@@ -21,12 +25,21 @@ pub(crate) async fn reader_loop(
     enc_leftover: BytesMut,
     mut dec: BytesMut,
     writer: Arc<Mutex<RpcWriter>>,
+    ping_tracker: Arc<Mutex<HashMap<i64, (Instant, u64)>>>,
+    rtt_stats: Arc<Mutex<HashMap<u64, (f64, f64)>>>,
+    _writer_id: u64,
+    degraded: Arc<AtomicBool>,
+    cancel: CancellationToken,
 ) -> Result<()> {
     let mut raw = enc_leftover;
+    let mut expected_seq: i32 = 0;
 
     loop {
         let mut tmp = [0u8; 16_384];
-        let n = rd.read(&mut tmp).await.map_err(ProxyError::Io)?;
+        let n = tokio::select! {
+            res = rd.read(&mut tmp) => res.map_err(ProxyError::Io)?,
+            _ = cancel.cancelled() => return Ok(()),
+        };
         if n == 0 {
             return Ok(());
         }
@@ -70,6 +83,14 @@ pub(crate) async fn reader_loop(
                 continue;
             }
 
+            let seq_no = i32::from_le_bytes(frame[4..8].try_into().unwrap());
+            if seq_no != expected_seq {
+                warn!(seq_no, expected = expected_seq, "ME RPC seq mismatch");
+                expected_seq = seq_no.wrapping_add(1);
+            } else {
+                expected_seq = expected_seq.wrapping_add(1);
+            }
+
             let payload = &frame[8..pe];
             if payload.len() < 4 {
                 continue;
@@ -119,6 +140,26 @@ pub(crate) async fn reader_loop(
                     warn!(error = %e, "PONG send failed");
                     break;
                 }
+            } else if pt == RPC_PONG_U32 && body.len() >= 8 {
+                let ping_id = i64::from_le_bytes(body[0..8].try_into().unwrap());
+                if let Some((sent, wid)) = {
+                    let mut guard = ping_tracker.lock().await;
+                    guard.remove(&ping_id)
+                } {
+                    let rtt = sent.elapsed().as_secs_f64() * 1000.0;
+                    let mut stats = rtt_stats.lock().await;
+                    let entry = stats.entry(wid).or_insert((rtt, rtt));
+                    entry.1 = entry.1 * 0.8 + rtt * 0.2;
+                    if rtt < entry.0 {
+                        entry.0 = rtt;
+                    } else {
+                        // allow slow baseline drift upward to avoid stale minimum
+                        entry.0 = entry.0 * 0.99 + rtt * 0.01;
+                    }
+                    let degraded_now = entry.1 > entry.0 * 2.0;
+                    degraded.store(degraded_now, Ordering::Relaxed);
+                    trace!(writer_id = wid, rtt_ms = rtt, ema_ms = entry.1, base_ms = entry.0, degraded = degraded_now, "ME RTT sample");
+                }
             } else {
                 debug!(
                     rpc_type = format_args!("0x{pt:08x}"),

src/transport/middle_proxy/registry.rs

@@ -1,42 +1,133 @@
 use std::collections::HashMap;
+use std::net::SocketAddr;
 use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::Arc;
 
-use tokio::sync::{RwLock, mpsc};
+use tokio::sync::{mpsc, Mutex, RwLock};
 
+use super::codec::RpcWriter;
 use super::MeResponse;
 
+#[derive(Clone)]
+pub struct ConnMeta {
+    pub target_dc: i16,
+    pub client_addr: SocketAddr,
+    pub our_addr: SocketAddr,
+    pub proto_flags: u32,
+}
+
+#[derive(Clone)]
+pub struct BoundConn {
+    pub conn_id: u64,
+    pub meta: ConnMeta,
+}
+
+#[derive(Clone)]
+pub struct ConnWriter {
+    pub writer_id: u64,
+    pub writer: Arc<Mutex<RpcWriter>>,
+}
+
 pub struct ConnRegistry {
     map: RwLock<HashMap<u64, mpsc::Sender<MeResponse>>>,
+    writers: RwLock<HashMap<u64, Arc<Mutex<RpcWriter>>>>,
+    writer_for_conn: RwLock<HashMap<u64, u64>>,
+    conns_for_writer: RwLock<HashMap<u64, Vec<u64>>>,
+    meta: RwLock<HashMap<u64, ConnMeta>>,
     next_id: AtomicU64,
 }
 
 impl ConnRegistry {
     pub fn new() -> Self {
-        // Avoid fully predictable conn_id sequence from 1.
         let start = rand::random::<u64>() | 1;
         Self {
             map: RwLock::new(HashMap::new()),
+            writers: RwLock::new(HashMap::new()),
+            writer_for_conn: RwLock::new(HashMap::new()),
+            conns_for_writer: RwLock::new(HashMap::new()),
+            meta: RwLock::new(HashMap::new()),
             next_id: AtomicU64::new(start),
         }
     }
 
     pub async fn register(&self) -> (u64, mpsc::Receiver<MeResponse>) {
         let id = self.next_id.fetch_add(1, Ordering::Relaxed);
-        let (tx, rx) = mpsc::channel(256);
+        let (tx, rx) = mpsc::channel(1024);
         self.map.write().await.insert(id, tx);
         (id, rx)
     }
 
     pub async fn unregister(&self, id: u64) {
         self.map.write().await.remove(&id);
+        self.meta.write().await.remove(&id);
+        if let Some(writer_id) = self.writer_for_conn.write().await.remove(&id) {
+            if let Some(list) = self.conns_for_writer.write().await.get_mut(&writer_id) {
+                list.retain(|c| *c != id);
+            }
+        }
     }
 
     pub async fn route(&self, id: u64, resp: MeResponse) -> bool {
         let m = self.map.read().await;
         if let Some(tx) = m.get(&id) {
-            tx.send(resp).await.is_ok()
+            tx.try_send(resp).is_ok()
         } else {
             false
         }
     }
+
+    pub async fn bind_writer(
+        &self,
+        conn_id: u64,
+        writer_id: u64,
+        writer: Arc<Mutex<RpcWriter>>,
+        meta: ConnMeta,
+    ) {
+        self.meta.write().await.entry(conn_id).or_insert(meta);
+        self.writer_for_conn.write().await.insert(conn_id, writer_id);
+        self.writers.write().await.entry(writer_id).or_insert_with(|| writer.clone());
+        self.conns_for_writer
+            .write()
+            .await
+            .entry(writer_id)
+            .or_insert_with(Vec::new)
+            .push(conn_id);
+    }
+
+    pub async fn get_writer(&self, conn_id: u64) -> Option<ConnWriter> {
+        let writer_id = {
+            let guard = self.writer_for_conn.read().await;
+            guard.get(&conn_id).cloned()
+        }?;
+        let writer = {
+            let guard = self.writers.read().await;
+            guard.get(&writer_id).cloned()
+        }?;
+        Some(ConnWriter { writer_id, writer })
+    }
+
+    pub async fn writer_lost(&self, writer_id: u64) -> Vec<BoundConn> {
+        self.writers.write().await.remove(&writer_id);
+        let conns = self.conns_for_writer.write().await.remove(&writer_id).unwrap_or_default();
+
+        let mut out = Vec::new();
+        let mut writer_for_conn = self.writer_for_conn.write().await;
+        let meta = self.meta.read().await;
+
+        for conn_id in conns {
+            writer_for_conn.remove(&conn_id);
+            if let Some(m) = meta.get(&conn_id) {
+                out.push(BoundConn {
+                    conn_id,
+                    meta: m.clone(),
+                });
+            }
+        }
+        out
+    }
+
+    pub async fn get_meta(&self, conn_id: u64) -> Option<ConnMeta> {
+        let guard = self.meta.read().await;
+        guard.get(&conn_id).cloned()
+    }
 }

src/transport/middle_proxy/rotation.rs

@@ -0,0 +1,42 @@
+use std::sync::Arc;
+use std::sync::atomic::Ordering;
+use std::time::Duration;
+
+use tracing::{info, warn};
+
+use crate::crypto::SecureRandom;
+
+use super::MePool;
+
+/// Periodically refresh ME connections to avoid long-lived degradation.
+pub async fn me_rotation_task(pool: Arc<MePool>, rng: Arc<SecureRandom>, interval: Duration) {
+    let interval = interval.max(Duration::from_secs(600));
+    loop {
+        tokio::time::sleep(interval).await;
+
+        let candidate = {
+            let ws = pool.writers.read().await;
+            if ws.is_empty() {
+                None
+            } else {
+                let idx = (pool.rr.load(std::sync::atomic::Ordering::Relaxed) as usize) % ws.len();
+                ws.get(idx).cloned()
+            }
+        };
+
+        let Some(w) = candidate else {
+            continue;
+        };
+
+        info!(addr = %w.addr, writer_id = w.id, "Rotating ME connection");
+        match pool.connect_one(w.addr, rng.as_ref()).await {
+            Ok(()) => {
+                // Remove old writer after new one is up.
+                pool.remove_writer_and_reroute(w.id).await;
+            }
+            Err(e) => {
+                warn!(addr = %w.addr, writer_id = w.id, error = %e, "ME rotation connect failed");
+            }
+        }
+    }
+}

src/transport/middle_proxy/secret.rs

@@ -1,6 +1,8 @@
 use std::time::Duration;
 
 use tracing::{debug, info, warn};
+use std::time::SystemTime;
+use httpdate;
 
 use crate::error::{ProxyError, Result};
 
@@ -51,7 +53,7 @@ pub async fn fetch_proxy_secret(cache_path: Option<&str>) -> Result<Vec<u8>> {
     }
 }
 
-async fn download_proxy_secret() -> Result<Vec<u8>> {
+pub async fn download_proxy_secret() -> Result<Vec<u8>> {
     let resp = reqwest::get("https://core.telegram.org/getProxySecret")
         .await
         .map_err(|e| ProxyError::Proxy(format!("Failed to download proxy-secret: {e}")))?;
@@ -63,6 +65,23 @@ async fn download_proxy_secret() -> Result<Vec<u8>> {
         )));
     }
 
+    if let Some(date) = resp.headers().get(reqwest::header::DATE) {
+        if let Ok(date_str) = date.to_str() {
+            if let Ok(server_time) = httpdate::parse_http_date(date_str) {
+                if let Ok(skew) = SystemTime::now().duration_since(server_time).or_else(|e| {
+                    server_time.duration_since(SystemTime::now()).map_err(|_| e)
+                }) {
+                    let skew_secs = skew.as_secs();
+                    if skew_secs > 60 {
+                        warn!(skew_secs, "Time skew >60s detected from proxy-secret Date header");
+                    } else if skew_secs > 30 {
+                        warn!(skew_secs, "Time skew >30s detected from proxy-secret Date header");
+                    }
+                }
+            }
+        }
+    }
+
     let data = resp
         .bytes()
         .await

src/transport/middle_proxy/send.rs

@@ -1,20 +1,22 @@
 use std::net::SocketAddr;
 use std::sync::Arc;
 use std::sync::atomic::Ordering;
+use std::time::Duration;
 
-use tokio::sync::Mutex;
 use tracing::{debug, warn};
 
 use crate::error::{ProxyError, Result};
-use crate::protocol::constants::{RPC_CLOSE_EXT_U32, TG_MIDDLE_PROXIES_V4};
+use crate::network::IpFamily;
+use crate::protocol::constants::RPC_CLOSE_EXT_U32;
 
 use super::MePool;
-use super::codec::RpcWriter;
 use super::wire::build_proxy_req_payload;
+use rand::seq::SliceRandom;
+use super::registry::ConnMeta;
 
 impl MePool {
     pub async fn send_proxy_req(
-        &self,
+        self: &Arc<Self>,
         conn_id: u64,
         target_dc: i16,
         client_addr: SocketAddr,
@@ -30,73 +32,131 @@ impl MePool {
             self.proxy_tag.as_deref(),
             proto_flags,
         );
+        let meta = ConnMeta {
+            target_dc,
+            client_addr,
+            our_addr,
+            proto_flags,
+        };
+        let mut emergency_attempts = 0;
 
         loop {
+            if let Some(current) = self.registry.get_writer(conn_id).await {
+                let send_res = {
+                    if let Ok(mut guard) = current.writer.try_lock() {
+                        let r = guard.send(&payload).await;
+                        drop(guard);
+                        r
+                    } else {
+                        current.writer.lock().await.send(&payload).await
+                    }
+                };
+                match send_res {
+                    Ok(()) => return Ok(()),
+                    Err(e) => {
+                        warn!(error = %e, writer_id = current.writer_id, "ME write failed");
+                        self.remove_writer_and_reroute(current.writer_id).await;
+                        continue;
+                    }
+                }
+            }
+
+            let mut writers_snapshot = {
                 let ws = self.writers.read().await;
                 if ws.is_empty() {
                     return Err(ProxyError::Proxy("All ME connections dead".into()));
                 }
-            let writers: Vec<(SocketAddr, Arc<Mutex<RpcWriter>>)> = ws.iter().cloned().collect();
+                ws.clone()
-            drop(ws);
+            };
 
-            let candidate_indices = candidate_indices_for_dc(&writers, target_dc);
+            let mut candidate_indices = self.candidate_indices_for_dc(&writers_snapshot, target_dc).await;
+            if candidate_indices.is_empty() {
+                // Emergency connect-on-demand
+                if emergency_attempts >= 3 {
+                    return Err(ProxyError::Proxy("No ME writers available for target DC".into()));
+                }
+                emergency_attempts += 1;
+                let map = self.proxy_map_v4.read().await;
+                if let Some(addrs) = map.get(&(target_dc as i32)) {
+                    let mut shuffled = addrs.clone();
+                    shuffled.shuffle(&mut rand::rng());
+                    drop(map);
+                    for (ip, port) in shuffled {
+                        let addr = SocketAddr::new(ip, port);
+                        if self.connect_one(addr, self.rng.as_ref()).await.is_ok() {
+                            break;
+                        }
+                    }
+                    tokio::time::sleep(Duration::from_millis(100 * emergency_attempts)).await;
+                    let ws2 = self.writers.read().await;
+                    writers_snapshot = ws2.clone();
+                    drop(ws2);
+                    candidate_indices = self.candidate_indices_for_dc(&writers_snapshot, target_dc).await;
+                }
                 if candidate_indices.is_empty() {
                     return Err(ProxyError::Proxy("No ME writers available for target DC".into()));
                 }
+            }
+
+            candidate_indices.sort_by_key(|idx| {
+                writers_snapshot[*idx]
+                    .degraded
+                    .load(Ordering::Relaxed)
+                    .then_some(1usize)
+                    .unwrap_or(0)
+            });
+
             let start = self.rr.fetch_add(1, Ordering::Relaxed) as usize % candidate_indices.len();
 
-            // Prefer immediately available writer to avoid waiting on stalled connection.
             for offset in 0..candidate_indices.len() {
-                let cidx = (start + offset) % candidate_indices.len();
+                let idx = candidate_indices[(start + offset) % candidate_indices.len()];
-                let idx = candidate_indices[cidx];
+                let w = &writers_snapshot[idx];
-                let w = writers[idx].1.clone();
+                if let Ok(mut guard) = w.writer.try_lock() {
-                if let Ok(mut guard) = w.try_lock() {
                     let send_res = guard.send(&payload).await;
                     drop(guard);
                     match send_res {
-                        Ok(()) => return Ok(()),
+                        Ok(()) => {
-                        Err(e) => {
+                            self.registry
-                            warn!(error = %e, "ME write failed, removing dead conn");
+                                .bind_writer(conn_id, w.id, w.writer.clone(), meta.clone())
-                            let mut ws = self.writers.write().await;
+                                .await;
-                            ws.retain(|(_, o)| !Arc::ptr_eq(o, &w));
+                            return Ok(());
-                            if ws.is_empty() {
-                                return Err(ProxyError::Proxy("All ME connections dead".into()));
                         }
+                        Err(e) => {
+                            warn!(error = %e, writer_id = w.id, "ME write failed");
+                            self.remove_writer_and_reroute(w.id).await;
                             continue;
                         }
                     }
                 }
             }
 
-            // All writers are currently busy, wait for the selected one.
+            let w = writers_snapshot[candidate_indices[start]].clone();
-            let w = writers[candidate_indices[start]].1.clone();
+            match w.writer.lock().await.send(&payload).await {
-            match w.lock().await.send(&payload).await {
+                Ok(()) => {
-                Ok(()) => return Ok(()),
+                    self.registry
-                Err(e) => {
+                        .bind_writer(conn_id, w.id, w.writer.clone(), meta.clone())
-                    warn!(error = %e, "ME write failed, removing dead conn");
+                        .await;
-                    let mut ws = self.writers.write().await;
+                    return Ok(());
-                    ws.retain(|(_, o)| !Arc::ptr_eq(o, &w));
-                    if ws.is_empty() {
-                        return Err(ProxyError::Proxy("All ME connections dead".into()));
                 }
+                Err(e) => {
+                    warn!(error = %e, writer_id = w.id, "ME write failed (blocking)");
+                    self.remove_writer_and_reroute(w.id).await;
                 }
             }
         }
     }
 
-    pub async fn send_close(&self, conn_id: u64) -> Result<()> {
+    pub async fn send_close(self: &Arc<Self>, conn_id: u64) -> Result<()> {
-        let ws = self.writers.read().await;
+        if let Some(w) = self.registry.get_writer(conn_id).await {
-        if !ws.is_empty() {
-            let w = ws[0].1.clone();
-            drop(ws);
             let mut p = Vec::with_capacity(12);
             p.extend_from_slice(&RPC_CLOSE_EXT_U32.to_le_bytes());
             p.extend_from_slice(&conn_id.to_le_bytes());
-            if let Err(e) = w.lock().await.send(&p).await {
+            if let Err(e) = w.writer.lock().await.send(&p).await {
                 debug!(error = %e, "ME close write failed");
-                let mut ws = self.writers.write().await;
+                self.remove_writer_and_reroute(w.writer_id).await;
-                ws.retain(|(_, o)| !Arc::ptr_eq(o, &w));
             }
+        } else {
+            debug!(conn_id, "ME close skipped (writer missing)");
         }
 
         self.registry.unregister(conn_id).await;
@@ -106,36 +166,59 @@ impl MePool {
     pub fn connection_count(&self) -> usize {
         self.writers.try_read().map(|w| w.len()).unwrap_or(0)
     }
-}
     
-fn candidate_indices_for_dc(
+    pub(super) async fn candidate_indices_for_dc(
-    writers: &[(SocketAddr, Arc<Mutex<RpcWriter>>)],
+        &self,
+        writers: &[super::pool::MeWriter],
         target_dc: i16,
-) -> Vec<usize> {
+    ) -> Vec<usize> {
-    let mut preferred = Vec::<SocketAddr>::new();
         let key = target_dc as i32;
-    if let Some(v) = TG_MIDDLE_PROXIES_V4.get(&key) {
+        let mut preferred = Vec::<SocketAddr>::new();
+
+        for family in self.family_order() {
+            let map_guard = match family {
+                IpFamily::V4 => self.proxy_map_v4.read().await,
+                IpFamily::V6 => self.proxy_map_v6.read().await,
+            };
+
+            if let Some(v) = map_guard.get(&key) {
                 preferred.extend(v.iter().map(|(ip, port)| SocketAddr::new(*ip, *port)));
             }
             if preferred.is_empty() {
                 let abs = key.abs();
-        if let Some(v) = TG_MIDDLE_PROXIES_V4.get(&abs) {
+                if let Some(v) = map_guard.get(&abs) {
                     preferred.extend(v.iter().map(|(ip, port)| SocketAddr::new(*ip, *port)));
                 }
             }
             if preferred.is_empty() {
                 let abs = key.abs();
-        if let Some(v) = TG_MIDDLE_PROXIES_V4.get(&-abs) {
+                if let Some(v) = map_guard.get(&-abs) {
                     preferred.extend(v.iter().map(|(ip, port)| SocketAddr::new(*ip, *port)));
                 }
             }
+            if preferred.is_empty() {
+                let def = self.default_dc.load(Ordering::Relaxed);
+                if def != 0 {
+                    if let Some(v) = map_guard.get(&def) {
+                        preferred.extend(v.iter().map(|(ip, port)| SocketAddr::new(*ip, *port)));
+                    }
+                }
+            }
+
+            drop(map_guard);
+
+            if !preferred.is_empty() && !self.decision.effective_multipath {
+                break;
+            }
+        }
+
         if preferred.is_empty() {
             return (0..writers.len()).collect();
         }
 
         let mut out = Vec::new();
-    for (idx, (addr, _)) in writers.iter().enumerate() {
+        for (idx, w) in writers.iter().enumerate() {
-        if preferred.iter().any(|p| p == addr) {
+            if preferred.iter().any(|p| *p == w.addr) {
                 out.push(idx);
             }
         }
@@ -143,4 +226,6 @@ fn candidate_indices_for_dc(
             return (0..writers.len()).collect();
         }
         out
+    }
+
 }

src/transport/middle_proxy/wire.rs

@@ -28,9 +28,7 @@ fn ipv4_to_mapped_v6_c_compat(ip: Ipv4Addr) -> [u8; 16] {
     buf[8..12].copy_from_slice(&(-0x10000i32).to_le_bytes());
 
     // Matches tl_store_int(htonl(remote_ip_host_order)).
-    let host_order = u32::from_ne_bytes(ip.octets());
+    buf[12..16].copy_from_slice(&ip.octets());
-    let network_order = host_order.to_be();
-    buf[12..16].copy_from_slice(&network_order.to_le_bytes());
 
     buf
 }
@@ -60,7 +58,7 @@ pub(crate) fn build_proxy_req_payload(
     append_mapped_addr_and_port(&mut b, client_addr);
     append_mapped_addr_and_port(&mut b, our_addr);
 
-    if proto_flags & 12 != 0 {
+    if proto_flags & RPC_FLAG_HAS_AD_TAG != 0 {
         let extra_start = b.len();
         b.extend_from_slice(&0u32.to_le_bytes());
 
@@ -104,3 +102,17 @@ pub fn proto_flags_for_tag(tag: crate::protocol::constants::ProtoTag, has_proxy_
         ProtoTag::Secure => flags | RPC_FLAG_PAD | RPC_FLAG_INTERMEDIATE,
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_ipv4_mapped_encoding() {
+        let ip = Ipv4Addr::new(149, 154, 175, 50);
+        let buf = ipv4_to_mapped_v6_c_compat(ip);
+        assert_eq!(&buf[0..10], &[0u8; 10]);
+        assert_eq!(&buf[10..12], &[0xff, 0xff]);
+        assert_eq!(&buf[12..16], &[149, 154, 175, 50]);
+    }
+}

src/transport/pool.rs

@@ -285,12 +285,17 @@ where
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::io::ErrorKind;
     use tokio::net::TcpListener;
     
     #[tokio::test]
     async fn test_pool_basic() {
         // Start a test server
-        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let listener = match TcpListener::bind("127.0.0.1:0").await {
+            Ok(l) => l,
+            Err(e) if e.kind() == ErrorKind::PermissionDenied => return,
+            Err(e) => panic!("bind failed: {e}"),
+        };
         let addr = listener.local_addr().unwrap();
         
         // Accept connections in background
@@ -303,7 +308,11 @@ mod tests {
         let pool = ConnectionPool::new();
         
         // Get a connection
-        let conn1 = pool.get(addr).await.unwrap();
+        let conn1 = match pool.get(addr).await {
+            Ok(c) => c,
+            Err(ProxyError::Io(e)) if e.kind() == ErrorKind::PermissionDenied => return,
+            Err(e) => panic!("connect failed: {e}"),
+        };
         
         // Return it to pool
         pool.put(addr, conn1).await;

src/transport/socket.rs

@@ -205,15 +205,29 @@ pub fn create_listener(addr: SocketAddr, options: &ListenOptions) -> Result<Sock
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::io::ErrorKind;
     use tokio::net::TcpListener;
     
     #[tokio::test]
     async fn test_configure_socket() {
-        let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let listener = match TcpListener::bind("127.0.0.1:0").await {
+            Ok(l) => l,
+            Err(e) if e.kind() == ErrorKind::PermissionDenied => return,
+            Err(e) => panic!("bind failed: {e}"),
+        };
         let addr = listener.local_addr().unwrap();
         
-        let stream = TcpStream::connect(addr).await.unwrap();
+        let stream = match TcpStream::connect(addr).await {
-        configure_tcp_socket(&stream, true, Duration::from_secs(30)).unwrap();
+            Ok(s) => s,
+            Err(e) if e.kind() == ErrorKind::PermissionDenied => return,
+            Err(e) => panic!("connect failed: {e}"),
+        };
+        if let Err(e) = configure_tcp_socket(&stream, true, Duration::from_secs(30)) {
+            if e.kind() == ErrorKind::PermissionDenied {
+                return;
+            }
+            panic!("configure_tcp_socket failed: {e}");
+        }
     }
     
     #[test]

src/transport/upstream.rs

@@ -2,6 +2,7 @@
 //! 
 //! IPv6/IPv4 connectivity checks with configurable preference.
 
+use std::collections::HashMap;
 use std::net::{SocketAddr, IpAddr};
 use std::sync::Arc;
 use std::time::Duration;
@@ -350,7 +351,13 @@ impl UpstreamManager {
 
     /// Ping all Telegram DCs through all upstreams.
     /// Tests BOTH IPv6 and IPv4, returns separate results for each.
-    pub async fn ping_all_dcs(&self, prefer_ipv6: bool) -> Vec<StartupPingResult> {
+    pub async fn ping_all_dcs(
+        &self,
+        prefer_ipv6: bool,
+        dc_overrides: &HashMap<String, Vec<String>>,
+        ipv4_enabled: bool,
+        ipv6_enabled: bool,
+    ) -> Vec<StartupPingResult> {
         let upstreams: Vec<(usize, UpstreamConfig)> = {
             let guard = self.upstreams.read().await;
             guard.iter().enumerate()
@@ -369,10 +376,8 @@ impl UpstreamManager {
                 UpstreamType::Socks5 { address, .. } => format!("socks5://{}", address),
             };
 
-            let mut v6_results = Vec::new();
+            let mut v6_results = Vec::with_capacity(NUM_DCS);
-            let mut v4_results = Vec::new();
+            if ipv6_enabled {
-
-            // === Ping IPv6 first ===
                 for dc_zero_idx in 0..NUM_DCS {
                     let dc_v6 = TG_DATACENTERS_V6[dc_zero_idx];
                     let addr_v6 = SocketAddr::new(dc_v6, TG_DATACENTER_PORT);
@@ -410,8 +415,20 @@ impl UpstreamManager {
                     };
                     v6_results.push(ping_result);
                 }
+            } else {
+                for dc_zero_idx in 0..NUM_DCS {
+                    let dc_v6 = TG_DATACENTERS_V6[dc_zero_idx];
+                    v6_results.push(DcPingResult {
+                        dc_idx: dc_zero_idx + 1,
+                        dc_addr: SocketAddr::new(dc_v6, TG_DATACENTER_PORT),
+                        rtt_ms: None,
+                        error: Some("ipv6 disabled".to_string()),
+                    });
+                }
+            }
 
-            // === Then ping IPv4 ===
+            let mut v4_results = Vec::with_capacity(NUM_DCS);
+            if ipv4_enabled {
                 for dc_zero_idx in 0..NUM_DCS {
                     let dc_v4 = TG_DATACENTERS_V4[dc_zero_idx];
                     let addr_v4 = SocketAddr::new(dc_v4, TG_DATACENTER_PORT);
@@ -449,6 +466,72 @@ impl UpstreamManager {
                     };
                     v4_results.push(ping_result);
                 }
+            } else {
+                for dc_zero_idx in 0..NUM_DCS {
+                    let dc_v4 = TG_DATACENTERS_V4[dc_zero_idx];
+                    v4_results.push(DcPingResult {
+                        dc_idx: dc_zero_idx + 1,
+                        dc_addr: SocketAddr::new(dc_v4, TG_DATACENTER_PORT),
+                        rtt_ms: None,
+                        error: Some("ipv4 disabled".to_string()),
+                    });
+                }
+            }
+
+            // === Ping DC overrides (v4/v6) ===
+            for (dc_key, addrs) in dc_overrides {
+                let dc_num: i16 = match dc_key.parse::<i16>() {
+                    Ok(v) if v > 0 => v,
+                    Err(_) => {
+                        warn!(dc = %dc_key, "Invalid dc_overrides key, skipping");
+                        continue;
+                    },
+                    _ => continue,
+                };
+                let dc_idx = dc_num as usize;
+                for addr_str in addrs {
+                    match addr_str.parse::<SocketAddr>() {
+                        Ok(addr) => {
+                            let is_v6 = addr.is_ipv6();
+                            if (is_v6 && !ipv6_enabled) || (!is_v6 && !ipv4_enabled) {
+                                continue;
+                            }
+                            let result = tokio::time::timeout(
+                                Duration::from_secs(DC_PING_TIMEOUT_SECS),
+                                self.ping_single_dc(&upstream_config, addr)
+                            ).await;
+
+                            let ping_result = match result {
+                                Ok(Ok(rtt_ms)) => DcPingResult {
+                                    dc_idx,
+                                    dc_addr: addr,
+                                    rtt_ms: Some(rtt_ms),
+                                    error: None,
+                                },
+                                Ok(Err(e)) => DcPingResult {
+                                    dc_idx,
+                                    dc_addr: addr,
+                                    rtt_ms: None,
+                                    error: Some(e.to_string()),
+                                },
+                                Err(_) => DcPingResult {
+                                    dc_idx,
+                                    dc_addr: addr,
+                                    rtt_ms: None,
+                                    error: Some("timeout".to_string()),
+                                },
+                            };
+
+                            if is_v6 {
+                                v6_results.push(ping_result);
+                            } else {
+                                v4_results.push(ping_result);
+                            }
+                        }
+                        Err(_) => warn!(dc = %dc_idx, addr = %addr_str, "Invalid dc_overrides address, skipping"),
+                    }
+                }
+            }
 
             // Check if both IP versions have at least one working DC
             let v6_has_working = v6_results.iter().any(|r| r.rtt_ms.is_some());
@@ -494,7 +577,7 @@ impl UpstreamManager {
 
     /// Background health check: rotates through DCs, 30s interval.
     /// Uses preferred IP version based on config.
-    pub async fn run_health_checks(&self, prefer_ipv6: bool) {
+    pub async fn run_health_checks(&self, prefer_ipv6: bool, ipv4_enabled: bool, ipv6_enabled: bool) {
         let mut dc_rotation = 0usize;
 
         loop {
@@ -503,16 +586,24 @@ impl UpstreamManager {
             let dc_zero_idx = dc_rotation % NUM_DCS;
             dc_rotation += 1;
 
-            let dc_addr = if prefer_ipv6 {
+            let primary_v6 = SocketAddr::new(TG_DATACENTERS_V6[dc_zero_idx], TG_DATACENTER_PORT);
-                SocketAddr::new(TG_DATACENTERS_V6[dc_zero_idx], TG_DATACENTER_PORT)
+            let primary_v4 = SocketAddr::new(TG_DATACENTERS_V4[dc_zero_idx], TG_DATACENTER_PORT);
+            let dc_addr = if prefer_ipv6 && ipv6_enabled {
+                primary_v6
+            } else if ipv4_enabled {
+                primary_v4
+            } else if ipv6_enabled {
+                primary_v6
             } else {
-                SocketAddr::new(TG_DATACENTERS_V4[dc_zero_idx], TG_DATACENTER_PORT)
+                continue;
             };
 
-            let fallback_addr = if prefer_ipv6 {
+            let fallback_addr = if dc_addr.is_ipv6() && ipv4_enabled {
-                SocketAddr::new(TG_DATACENTERS_V4[dc_zero_idx], TG_DATACENTER_PORT)
+                Some(primary_v4)
+            } else if dc_addr.is_ipv4() && ipv6_enabled {
+                Some(primary_v6)
             } else {
-                SocketAddr::new(TG_DATACENTERS_V6[dc_zero_idx], TG_DATACENTER_PORT)
+                None
             };
 
             let count = self.upstreams.read().await.len();
@@ -551,6 +642,7 @@ impl UpstreamManager {
                         // Try fallback
                         debug!(dc = dc_zero_idx + 1, "Health check failed, trying fallback");
 
+                        if let Some(fallback_addr) = fallback_addr {
                             let start2 = Instant::now();
                             let result2 = tokio::time::timeout(
                                 Duration::from_secs(10),
@@ -595,6 +687,17 @@ impl UpstreamManager {
                                 }
                             }
                             u.last_check = std::time::Instant::now();
+                            continue;
+                        }
+
+                        let mut guard = self.upstreams.write().await;
+                        let u = &mut guard[i];
+                        u.fails += 1;
+                        if u.fails > 3 {
+                            u.healthy = false;
+                            warn!("Upstream unhealthy (no fallback family)");
+                        }
+                        u.last_check = std::time::Instant::now();
                     }
                 }
             }

tools/dc.py

@@ -0,0 +1,204 @@
+"""Telegram datacenter server checker."""
+
+from __future__ import annotations
+
+import asyncio
+from dataclasses import dataclass, field
+from itertools import groupby
+from operator import attrgetter
+from pathlib import Path
+from typing import TYPE_CHECKING
+
+from telethon import TelegramClient
+from telethon.tl.functions.help import GetConfigRequest
+
+if TYPE_CHECKING:
+    from telethon.tl.types import DcOption
+
+API_ID: int = 123456
+API_HASH: str = ""
+SESSION_NAME: str = "session"
+OUTPUT_FILE: Path = Path("telegram_servers.txt")
+
+_CONSOLE_FLAG_MAP: dict[str, str] = {
+    "IPv6": "IPv6",
+    "MEDIA-ONLY": "🎬 MEDIA-ONLY",
+    "CDN": "📦 CDN",
+    "TCPO": "🔒 TCPO",
+    "STATIC": "📌 STATIC",
+}
+
+
+@dataclass(frozen=True, slots=True)
+class DCServer:
+    """Typed representation of a Telegram DC server.
+
+    Attributes:
+        dc_id: Datacenter identifier.
+        ip: Server IP address.
+        port: Server port.
+        flags: Active flag labels (plain, without emoji).
+    """
+
+    dc_id: int
+    ip: str
+    port: int
+    flags: frozenset[str] = field(default_factory=frozenset)
+
+    @classmethod
+    def from_option(cls, dc: DcOption) -> DCServer:
+        """Create from a Telethon DcOption.
+
+        Args:
+            dc: Raw DcOption object.
+
+        Returns:
+            Parsed DCServer instance.
+        """
+        checks: dict[str, bool] = {
+            "IPv6": dc.ipv6,
+            "MEDIA-ONLY": dc.media_only,
+            "CDN": dc.cdn,
+            "TCPO": dc.tcpo_only,
+            "STATIC": dc.static,
+        }
+        return cls(
+            dc_id=dc.id,
+            ip=dc.ip_address,
+            port=dc.port,
+            flags=frozenset(k for k, v in checks.items() if v),
+        )
+
+    def flags_display(self, *, emoji: bool = False) -> str:
+        """Formatted flags string.
+
+        Args:
+            emoji: Whether to include emoji prefixes.
+
+        Returns:
+            Bracketed flags or '[STANDARD]'.
+        """
+        if not self.flags:
+            return "[STANDARD]"
+        labels = sorted(
+            _CONSOLE_FLAG_MAP[f] if emoji else f for f in self.flags
+        )
+        return f"[{', '.join(labels)}]"
+
+
+class TelegramDCChecker:
+    """Fetches and displays Telegram DC configuration.
+
+    Attributes:
+        _client: Telethon client instance.
+        _servers: Parsed server list.
+    """
+
+    def __init__(self) -> None:
+        """Initialize the checker."""
+        self._client = TelegramClient(SESSION_NAME, API_ID, API_HASH)
+        self._servers: list[DCServer] = []
+
+    async def run(self) -> None:
+        """Connect, fetch config, display and save results."""
+        print("🔄 Подключаемся к Telegram...")  # noqa: T201
+        try:
+            await self._client.start()
+            print("✅ Подключение установлено!\n")  # noqa: T201
+
+            print("📡 Запрашиваем конфигурацию серверов...")  # noqa: T201
+            config = await self._client(GetConfigRequest())
+            self._servers = [DCServer.from_option(dc) for dc in config.dc_options]
+
+            self._print(config)
+            self._save(config)
+        finally:
+            await self._client.disconnect()
+            print("\n👋 Отключились от Telegram")  # noqa: T201
+
+    def _grouped(self) -> dict[int, list[DCServer]]:
+        """Group servers by DC ID.
+
+        Returns:
+            Ordered mapping of DC ID to servers.
+        """
+        ordered = sorted(self._servers, key=attrgetter("dc_id"))
+        return {k: list(g) for k, g in groupby(ordered, key=attrgetter("dc_id"))}
+
+    def _print(self, config: object) -> None:
+        """Print results to stdout in original format.
+
+        Args:
+            config: Raw Telegram config.
+        """
+        sep = "=" * 80
+        dash = "-" * 80
+        total = len(self._servers)
+
+        print(f"📊 Получено серверов: {total}\n")  # noqa: T201
+        print(sep)  # noqa: T201
+
+        for dc_id, servers in self._grouped().items():
+            print(f"\n🌐 DATACENTER {dc_id} ({len(servers)} серверов)")  # noqa: T201
+            print(dash)  # noqa: T201
+            for s in servers:
+                print(f"  {s.ip:45}:{s.port:5} {s.flags_display(emoji=True)}")  # noqa: T201
+
+        ipv4 = total - self._flag_count("IPv6")
+        print(f"\n{sep}")  # noqa: T201
+        print("📈 СТАТИСТИКА:")  # noqa: T201
+        print(sep)  # noqa: T201
+        print(f"  Всего серверов:      {total}")  # noqa: T201
+        print(f"  IPv4 серверы:        {ipv4}")  # noqa: T201
+        print(f"  IPv6 серверы:        {self._flag_count('IPv6')}")  # noqa: T201
+        print(f"  Media-only:          {self._flag_count('MEDIA-ONLY')}")  # noqa: T201
+        print(f"  CDN серверы:         {self._flag_count('CDN')}")  # noqa: T201
+        print(f"  TCPO-only:           {self._flag_count('TCPO')}")  # noqa: T201
+        print(f"  Static:              {self._flag_count('STATIC')}")  # noqa: T201
+
+        print(f"\n{sep}")  # noqa: T201
+        print("ℹ️  ДОПОЛНИТЕЛЬНАЯ ИНФОРМАЦИЯ:")  # noqa: T201
+        print(sep)  # noqa: T201
+        print(f"  Дата конфигурации:   {config.date}")  # noqa: T201  # type: ignore[attr-defined]
+        print(f"  Expires:             {config.expires}")  # noqa: T201  # type: ignore[attr-defined]
+        print(f"  Test mode:           {config.test_mode}")  # noqa: T201  # type: ignore[attr-defined]
+        print(f"  This DC:             {config.this_dc}")  # noqa: T201  # type: ignore[attr-defined]
+
+    def _flag_count(self, flag: str) -> int:
+        """Count servers with a given flag.
+
+        Args:
+            flag: Flag name.
+
+        Returns:
+            Count of matching servers.
+        """
+        return sum(1 for s in self._servers if flag in s.flags)
+
+    def _save(self, config: object) -> None:
+        """Save results to file in original format.
+
+        Args:
+            config: Raw Telegram config.
+        """
+        parts: list[str] = []
+        parts.append("TELEGRAM DATACENTER SERVERS\n")
+        parts.append("=" * 80 + "\n\n")
+
+        for dc_id, servers in self._grouped().items():
+            parts.append(f"\nDATACENTER {dc_id} ({len(servers)} servers)\n")
+            parts.append("-" * 80 + "\n")
+            for s in servers:
+                parts.append(f"  {s.ip}:{s.port} {s.flags_display(emoji=False)}\n")
+
+        parts.append(f"\n\nTotal servers: {len(self._servers)}\n")
+        parts.append(f"Generated: {config.date}\n")  # type: ignore[attr-defined]
+
+        OUTPUT_FILE.write_text("".join(parts), encoding="utf-8")
+
+        print(f"\n💾 Сохраняем результаты в файл {OUTPUT_FILE}...")  # noqa: T201
+        print(f"✅ Результаты сохранены в {OUTPUT_FILE}")  # noqa: T201
+
+
+if __name__ == "__main__":
+    asyncio.run(TelegramDCChecker().run())