1.2.0.2 Special DC support: merge pull request #32 from telemt/1.2.0.2

1.2.0.2 Special DC support

.github/workflows/rust.yml

@@ -14,6 +14,11 @@ jobs:
     name: Build
     runs-on: ubuntu-latest
 
+    permissions:
+      contents: read
+      actions: write
+      checks: write
+
     steps:
     - name: Checkout repository
       uses: actions/checkout@v4

Cargo.toml

@@ -1,15 +1,14 @@
 [package]
 name = "telemt"
-version = "1.0.0"
-edition = "2021"
-rust-version = "1.75"
+version = "1.2.0"
+edition = "2024"
 
 [dependencies]
 # C
 libc = "0.2"
 
 # Async runtime
-tokio = { version = "1.35", features = ["full", "tracing"] }
+tokio = { version = "1.42", features = ["full", "tracing"] }
 tokio-util = { version = "0.7", features = ["codec"] }
 
 # Crypto
@@ -20,41 +19,41 @@ sha2 = "0.10"
 sha1 = "0.10"
 md-5 = "0.10"
 hmac = "0.12"
-crc32fast = "1.3"
+crc32fast = "1.4"
+zeroize = { version = "1.8", features = ["derive"] }
 
 # Network
 socket2 = { version = "0.5", features = ["all"] }
-rustls = "0.22"
 
-# Serial
+# Serialization
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 toml = "0.8"
 
 # Utils
-bytes = "1.5"
-thiserror = "1.0"
+bytes = "1.9"
+thiserror = "2.0"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 parking_lot = "0.12"
 dashmap = "5.5"
 lru = "0.12"
-rand = "0.8"
+rand = "0.9"
 chrono = { version = "0.4", features = ["serde"] }
 hex = "0.4"
-base64 = "0.21"
+base64 = "0.22"
 url = "2.5"
-regex = "1.10"
-once_cell = "1.19"
+regex = "1.11"
 crossbeam-queue = "0.3"
 
 # HTTP
-reqwest = { version = "0.11", features = ["rustls-tls"], default-features = false }
+reqwest = { version = "0.12", features = ["rustls-tls"], default-features = false }
 
 [dev-dependencies]
 tokio-test = "0.4"
 criterion = "0.5"
 proptest = "1.4"
+futures = "0.3"
 
 [[bench]]
 name = "crypto_bench"

README.md

@@ -2,6 +2,26 @@
 
 **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
+**Важное сообщение для пользователей из России**
+
+Мы работаем над проектом с Нового года и сейчас готовим новый релиз - 1.2
+
+В нём имплементируется поддержка Middle Proxy Protocol - основного терминатора для Ad Tag:
+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
+
+**Important message for users from Russia**
+
+We've been working on the project since December 30 and are currently preparing a new release – 1.2
+
+It implements support for the Middle Proxy Protocol – the primary point for the Ad Tag:
+development on it started on February 6th, and by February 10th, "big activity" in Russia had already "taken place"...
+
+If you have expertise in asynchronous network applications – we are open to ideas and pull requests!
+
+# Features
 💥 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) 

config.toml

@@ -6,8 +6,13 @@ show_link = ["hello"]
 [general]
 prefer_ipv6 = false
 fast_mode = true
-use_middle_proxy = false
-# ad_tag = "..."
+use_middle_proxy = true
+ad_tag = "00000000000000000000000000000000"
+
+# Log level: debug | verbose | normal | silent
+# Can be overridden with --silent or --log-level CLI flags
+# RUST_LOG env var takes absolute priority over all of these
+log_level = "normal"
 
 [general.modes]
 classic = false
@@ -39,16 +44,16 @@ client_ack = 300
 
 # === Anti-Censorship & Masking ===
 [censorship]
-tls_domain = "petrovich.ru"
+tls_domain = "google.ru"
 mask = true
 mask_port = 443
 # mask_host = "petrovich.ru" # Defaults to tls_domain if not set
 fake_cert_len = 2048
 
 # === Access Control & Users ===
-# username "hello" is used for example
 [access]
 replay_check_len = 65536
+replay_window_secs = 1800
 ignore_time_skew = false
 
 [access.users]
@@ -62,15 +67,11 @@ hello = "00000000000000000000000000000000"
 # hello = 1073741824 # 1 GB
 
 # === Upstreams & Routing ===
-# By default, direct connection is used, but you can add SOCKS proxy
-
-# Direct - Default
 [[upstreams]]
 type = "direct"
 enabled = true
 weight = 10
 
-# SOCKS5
 # [[upstreams]]
 # type = "socks5"
 # address = "127.0.0.1:9050"

src/cli.rs

@@ -0,0 +1,300 @@
+//! CLI commands: --init (fire-and-forget setup)
+
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+use rand::Rng;
+
+/// Options for the init command
+pub struct InitOptions {
+    pub port: u16,
+    pub domain: String,
+    pub secret: Option<String>,
+    pub username: String,
+    pub config_dir: PathBuf,
+    pub no_start: bool,
+}
+
+impl Default for InitOptions {
+    fn default() -> Self {
+        Self {
+            port: 443,
+            domain: "www.google.com".to_string(),
+            secret: None,
+            username: "user".to_string(),
+            config_dir: PathBuf::from("/etc/telemt"),
+            no_start: false,
+        }
+    }
+}
+
+/// Parse --init subcommand options from CLI args.
+///
+/// Returns `Some(InitOptions)` if `--init` was found, `None` otherwise.
+pub fn parse_init_args(args: &[String]) -> Option<InitOptions> {
+    if !args.iter().any(|a| a == "--init") {
+        return None;
+    }
+    
+    let mut opts = InitOptions::default();
+    let mut i = 0;
+    
+    while i < args.len() {
+        match args[i].as_str() {
+            "--port" => {
+                i += 1;
+                if i < args.len() {
+                    opts.port = args[i].parse().unwrap_or(443);
+                }
+            }
+            "--domain" => {
+                i += 1;
+                if i < args.len() {
+                    opts.domain = args[i].clone();
+                }
+            }
+            "--secret" => {
+                i += 1;
+                if i < args.len() {
+                    opts.secret = Some(args[i].clone());
+                }
+            }
+            "--user" => {
+                i += 1;
+                if i < args.len() {
+                    opts.username = args[i].clone();
+                }
+            }
+            "--config-dir" => {
+                i += 1;
+                if i < args.len() {
+                    opts.config_dir = PathBuf::from(&args[i]);
+                }
+            }
+            "--no-start" => {
+                opts.no_start = true;
+            }
+            _ => {}
+        }
+        i += 1;
+    }
+    
+    Some(opts)
+}
+
+/// Run the fire-and-forget setup.
+pub fn run_init(opts: InitOptions) -> Result<(), Box<dyn std::error::Error>> {
+    eprintln!("[telemt] Fire-and-forget setup");
+    eprintln!();
+    
+    // 1. Generate or validate secret
+    let secret = match opts.secret {
+        Some(s) => {
+            if s.len() != 32 || !s.chars().all(|c| c.is_ascii_hexdigit()) {
+                eprintln!("[error] Secret must be exactly 32 hex characters");
+                std::process::exit(1);
+            }
+            s
+        }
+        None => generate_secret(),
+    };
+    
+    eprintln!("[+] Secret: {}", secret);
+    eprintln!("[+] User:   {}", opts.username);
+    eprintln!("[+] Port:   {}", opts.port);
+    eprintln!("[+] Domain: {}", opts.domain);
+    
+    // 2. Create config directory
+    fs::create_dir_all(&opts.config_dir)?;
+    let config_path = opts.config_dir.join("config.toml");
+    
+    // 3. Write config
+    let config_content = generate_config(&opts.username, &secret, opts.port, &opts.domain);
+    fs::write(&config_path, &config_content)?;
+    eprintln!("[+] Config written to {}", config_path.display());
+    
+    // 4. Write systemd unit
+    let exe_path = std::env::current_exe()
+        .unwrap_or_else(|_| PathBuf::from("/usr/local/bin/telemt"));
+    
+    let unit_path = Path::new("/etc/systemd/system/telemt.service");
+    let unit_content = generate_systemd_unit(&exe_path, &config_path);
+    
+    match fs::write(unit_path, &unit_content) {
+        Ok(()) => {
+            eprintln!("[+] Systemd unit written to {}", unit_path.display());
+        }
+        Err(e) => {
+            eprintln!("[!] Cannot write systemd unit (run as root?): {}", e);
+            eprintln!("[!] Manual unit file content:");
+            eprintln!("{}", unit_content);
+            
+            // Still print links and config
+            print_links(&opts.username, &secret, opts.port, &opts.domain);
+            return Ok(());
+        }
+    }
+    
+    // 5. Reload systemd
+    run_cmd("systemctl", &["daemon-reload"]);
+    
+    // 6. Enable service
+    run_cmd("systemctl", &["enable", "telemt.service"]);
+    eprintln!("[+] Service enabled");
+    
+    // 7. Start service (unless --no-start)
+    if !opts.no_start {
+        run_cmd("systemctl", &["start", "telemt.service"]);
+        eprintln!("[+] Service started");
+        
+        // Brief delay then check status
+        std::thread::sleep(std::time::Duration::from_secs(1));
+        let status = Command::new("systemctl")
+            .args(["is-active", "telemt.service"])
+            .output();
+        
+        match status {
+            Ok(out) if out.status.success() => {
+                eprintln!("[+] Service is running");
+            }
+            _ => {
+                eprintln!("[!] Service may not have started correctly");
+                eprintln!("[!] Check: journalctl -u telemt.service -n 20");
+            }
+        }
+    } else {
+        eprintln!("[+] Service not started (--no-start)");
+        eprintln!("[+] Start manually: systemctl start telemt.service");
+    }
+    
+    eprintln!();
+    
+    // 8. Print links
+    print_links(&opts.username, &secret, opts.port, &opts.domain);
+    
+    Ok(())
+}
+
+fn generate_secret() -> String {
+    let mut rng = rand::rng();
+    let bytes: Vec<u8> = (0..16).map(|_| rng.random::<u8>()).collect();
+    hex::encode(bytes)
+}
+
+fn generate_config(username: &str, secret: &str, port: u16, domain: &str) -> String {
+    format!(
+r#"# Telemt MTProxy — auto-generated config
+# Re-run `telemt --init` to regenerate
+
+show_link = ["{username}"]
+
+[general]
+prefer_ipv6 = false
+fast_mode = true
+use_middle_proxy = false
+log_level = "normal"
+
+[general.modes]
+classic = false
+secure = false
+tls = true
+
+[server]
+port = {port}
+listen_addr_ipv4 = "0.0.0.0"
+listen_addr_ipv6 = "::"
+
+[[server.listeners]]
+ip = "0.0.0.0"
+
+[[server.listeners]]
+ip = "::"
+
+[timeouts]
+client_handshake = 15
+tg_connect = 10
+client_keepalive = 60
+client_ack = 300
+
+[censorship]
+tls_domain = "{domain}"
+mask = true
+mask_port = 443
+fake_cert_len = 2048
+
+[access]
+replay_check_len = 65536
+replay_window_secs = 1800
+ignore_time_skew = false
+
+[access.users]
+{username} = "{secret}"
+
+[[upstreams]]
+type = "direct"
+enabled = true
+weight = 10
+"#,
+        username = username,
+        secret = secret,
+        port = port,
+        domain = domain,
+    )
+}
+
+fn generate_systemd_unit(exe_path: &Path, config_path: &Path) -> String {
+    format!(
+r#"[Unit]
+Description=Telemt MTProxy
+Documentation=https://github.com/nicepkg/telemt
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+ExecStart={exe} {config}
+Restart=always
+RestartSec=5
+LimitNOFILE=65535
+# Security hardening
+NoNewPrivileges=true
+ProtectSystem=strict
+ProtectHome=true
+ReadWritePaths=/etc/telemt
+PrivateTmp=true
+
+[Install]
+WantedBy=multi-user.target
+"#,
+        exe = exe_path.display(),
+        config = config_path.display(),
+    )
+}
+
+fn run_cmd(cmd: &str, args: &[&str]) {
+    match Command::new(cmd).args(args).output() {
+        Ok(output) => {
+            if !output.status.success() {
+                let stderr = String::from_utf8_lossy(&output.stderr);
+                eprintln!("[!] {} {} failed: {}", cmd, args.join(" "), stderr.trim());
+            }
+        }
+        Err(e) => {
+            eprintln!("[!] Failed to run {} {}: {}", cmd, args.join(" "), e);
+        }
+    }
+}
+
+fn print_links(username: &str, secret: &str, port: u16, domain: &str) {
+    let domain_hex = hex::encode(domain);
+    
+    println!("=== Proxy Links ===");
+    println!("[{}]", username);
+    println!("  EE-TLS:  tg://proxy?server=YOUR_SERVER_IP&port={}&secret=ee{}{}", 
+        port, secret, domain_hex);
+    println!();
+    println!("Replace YOUR_SERVER_IP with your server's public IP.");
+    println!("The proxy will auto-detect and display the correct link on startup.");
+    println!("Check: journalctl -u telemt.service | head -30");
+    println!("===================");
+}

src/config/mod.rs

@@ -1,7 +1,7 @@
 //! Configuration
 
 use std::collections::HashMap;
-use std::net::IpAddr;
+use std::net::{IpAddr, SocketAddr};
 use std::path::Path;
 use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
@@ -14,6 +14,7 @@ fn default_port() -> u16 { 443 }
 fn default_tls_domain() -> String { "www.google.com".to_string() }
 fn default_mask_port() -> u16 { 443 }
 fn default_replay_check_len() -> usize { 65536 }
+fn default_replay_window_secs() -> u64 { 1800 }
 fn default_handshake_timeout() -> u64 { 15 }
 fn default_connect_timeout() -> u64 { 10 }
 fn default_keepalive() -> u64 { 60 }
@@ -28,6 +29,59 @@ fn default_metrics_whitelist() -> Vec<IpAddr> {
     ]
 }
 
+// ============= Log Level =============
+
+/// Logging verbosity level
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Default)]
+#[serde(rename_all = "lowercase")]
+pub enum LogLevel {
+    /// All messages including trace (trace + debug + info + warn + error)
+    Debug,
+    /// Detailed operational logs (debug + info + warn + error)
+    Verbose,
+    /// Standard operational logs (info + warn + error)
+    #[default]
+    Normal,
+    /// Minimal output: only warnings and errors (warn + error).
+    /// Startup messages (config, DC connectivity, proxy links) are always shown
+    /// via info! before the filter is applied.
+    Silent,
+}
+
+impl LogLevel {
+    /// Convert to tracing EnvFilter directive string
+    pub fn to_filter_str(&self) -> &'static str {
+        match self {
+            LogLevel::Debug => "trace",
+            LogLevel::Verbose => "debug",
+            LogLevel::Normal => "info",
+            LogLevel::Silent => "warn",
+        }
+    }
+
+    /// Parse from a loose string (CLI argument)
+    pub fn from_str_loose(s: &str) -> Self {
+        match s.to_lowercase().as_str() {
+            "debug" | "trace" => LogLevel::Debug,
+            "verbose" => LogLevel::Verbose,
+            "normal" | "info" => LogLevel::Normal,
+            "silent" | "quiet" | "error" | "warn" => LogLevel::Silent,
+            _ => LogLevel::Normal,
+        }
+    }
+}
+
+impl std::fmt::Display for LogLevel {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            LogLevel::Debug => write!(f, "debug"),
+            LogLevel::Verbose => write!(f, "verbose"),
+            LogLevel::Normal => write!(f, "normal"),
+            LogLevel::Silent => write!(f, "silent"),
+        }
+    }
+}
+
 // ============= Sub-Configs =============
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -62,6 +116,9 @@ pub struct GeneralConfig {
 
     #[serde(default)]
     pub ad_tag: Option<String>,
+    
+    #[serde(default)]
+    pub log_level: LogLevel,
 }
 
 impl Default for GeneralConfig {
@@ -72,6 +129,7 @@ impl Default for GeneralConfig {
             fast_mode: true,
             use_middle_proxy: false,
             ad_tag: None,
+            log_level: LogLevel::Normal,
         }
     }
 }
@@ -187,6 +245,9 @@ pub struct AccessConfig {
     #[serde(default = "default_replay_check_len")]
     pub replay_check_len: usize,
     
+    #[serde(default = "default_replay_window_secs")]
+    pub replay_window_secs: u64,
+    
     #[serde(default)]
     pub ignore_time_skew: bool,
 }
@@ -201,6 +262,7 @@ impl Default for AccessConfig {
             user_expirations: HashMap::new(),
             user_data_quota: HashMap::new(),
             replay_check_len: default_replay_check_len(),
+            replay_window_secs: default_replay_window_secs(),
             ignore_time_skew: false,
         }
     }
@@ -274,6 +336,21 @@ pub struct ProxyConfig {
 
     #[serde(default)]
     pub show_link: Vec<String>,
+
+    /// DC address overrides for non-standard DCs (CDN, media, test, etc.)
+    /// Keys are DC indices as strings, values are "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"
+    #[serde(default)]
+    pub dc_overrides: HashMap<String, String>,
+
+    /// Default DC index (1-5) for unmapped non-standard DCs.
+    /// Matches the C implementation's `default <dc_id>` config directive.
+    /// If not set, defaults to 2 (matching Telegram's official `default 2;` in proxy-multi.conf).
+    #[serde(default)]
+    pub default_dc: Option<u8>,
 }
 
 impl ProxyConfig {
@@ -299,20 +376,14 @@ impl ProxyConfig {
             return Err(ProxyError::Config("tls_domain cannot be empty".to_string()));
         }
         
-        // Warn if using default tls_domain
-        if config.censorship.tls_domain == "www.google.com" {
-            tracing::warn!("Using default tls_domain (www.google.com). Consider setting a custom domain in config.toml");
-        }
-        
         // Default mask_host to tls_domain if not set
         if config.censorship.mask_host.is_none() {
-            tracing::info!("mask_host not set, using tls_domain ({}) for masking", config.censorship.tls_domain);
             config.censorship.mask_host = Some(config.censorship.tls_domain.clone());
         }
         
         // Random fake_cert_len
         use rand::Rng;
-        config.censorship.fake_cert_len = rand::thread_rng().gen_range(1024..4096);
+        config.censorship.fake_cert_len = rand::rng().gen_range(1024..4096);
         
         // Migration: Populate listeners if empty
         if config.server.listeners.is_empty() {
@@ -353,7 +424,6 @@ impl ProxyConfig {
             return Err(ProxyError::Config("No modes enabled".to_string()));
         }
         
-        // Validate tls_domain format (basic check)
         if self.censorship.tls_domain.contains(' ') || self.censorship.tls_domain.contains('/') {
             return Err(ProxyError::Config(
                 format!("Invalid tls_domain: '{}'. Must be a valid domain name", self.censorship.tls_domain)

src/crypto/aes.rs

@@ -1,9 +1,19 @@
 //! AES encryption implementations
 //!
 //! Provides AES-256-CTR and AES-256-CBC modes for MTProto encryption.
+//!
+//! ## Zeroize policy
+//!
+//! - `AesCbc` stores raw key/IV bytes and zeroizes them on drop.
+//! - `AesCtr` wraps an opaque `Aes256Ctr` cipher from the `ctr` crate.
+//!   The expanded key schedule lives inside that type and cannot be
+//!   zeroized from outside. Callers that hold raw key material (e.g.
+//!   `HandshakeSuccess`, `ObfuscationParams`) are responsible for
+//!   zeroizing their own copies.
 
 use aes::Aes256;
 use ctr::{Ctr128BE, cipher::{KeyIvInit, StreamCipher}};
+use zeroize::Zeroize;
 use crate::error::{ProxyError, Result};
 
 type Aes256Ctr = Ctr128BE<Aes256>;
@@ -12,7 +22,12 @@ type Aes256Ctr = Ctr128BE<Aes256>;
 
 /// AES-256-CTR encryptor/decryptor
 /// 
-/// CTR mode is symmetric - encryption and decryption are the same operation.
+/// CTR mode is symmetric — encryption and decryption are the same operation.
+///
+/// **Zeroize note:** The inner `Aes256Ctr` cipher state (expanded key schedule
+/// + counter) is opaque and cannot be zeroized. If you need to protect key
+/// material, zeroize the `[u8; 32]` key and `u128` IV at the call site
+/// before dropping them.
 pub struct AesCtr {
     cipher: Aes256Ctr,
 }
@@ -62,14 +77,23 @@ impl AesCtr {
 
 /// AES-256-CBC cipher with proper chaining
 ///
-/// Unlike CTR mode, CBC is NOT symmetric - encryption and decryption
+/// Unlike CTR mode, CBC is NOT symmetric — encryption and decryption
 /// are different operations. This implementation handles CBC chaining
 /// correctly across multiple blocks.
+///
+/// Key and IV are zeroized on drop.
 pub struct AesCbc {
     key: [u8; 32],
     iv: [u8; 16],
 }
 
+impl Drop for AesCbc {
+    fn drop(&mut self) {
+        self.key.zeroize();
+        self.iv.zeroize();
+    }
+}
+
 impl AesCbc {
     /// AES block size
     const BLOCK_SIZE: usize = 16;
@@ -141,17 +165,9 @@ impl AesCbc {
         
         for chunk in data.chunks(Self::BLOCK_SIZE) {
             let plaintext: [u8; 16] = chunk.try_into().unwrap();
-            
-            // XOR plaintext with previous ciphertext (or IV for first block)
             let xored = Self::xor_blocks(&plaintext, &prev_ciphertext);
-            
-            // Encrypt the XORed block
             let ciphertext = self.encrypt_block(&xored, &key_schedule);
-            
-            // Save for next iteration
             prev_ciphertext = ciphertext;
-            
-            // Append to result
             result.extend_from_slice(&ciphertext);
         }
         
@@ -180,17 +196,9 @@ impl AesCbc {
         
         for chunk in data.chunks(Self::BLOCK_SIZE) {
             let ciphertext: [u8; 16] = chunk.try_into().unwrap();
-            
-            // Decrypt the block
             let decrypted = self.decrypt_block(&ciphertext, &key_schedule);
-            
-            // XOR with previous ciphertext (or IV for first block)
             let plaintext = Self::xor_blocks(&decrypted, &prev_ciphertext);
-            
-            // Save current ciphertext for next iteration
             prev_ciphertext = ciphertext;
-            
-            // Append to result
             result.extend_from_slice(&plaintext);
         }
         
@@ -217,16 +225,13 @@ impl AesCbc {
         for i in (0..data.len()).step_by(Self::BLOCK_SIZE) {
             let block = &mut data[i..i + Self::BLOCK_SIZE];
             
-            // XOR with previous ciphertext
             for j in 0..Self::BLOCK_SIZE {
                 block[j] ^= prev_ciphertext[j];
             }
             
-            // Encrypt in-place
             let block_array: &mut [u8; 16] = block.try_into().unwrap();
             *block_array = self.encrypt_block(block_array, &key_schedule);
             
-            // Save for next iteration
             prev_ciphertext = *block_array;
         }
         
@@ -248,26 +253,20 @@ impl AesCbc {
         use aes::cipher::KeyInit;
         let key_schedule = aes::Aes256::new((&self.key).into());
         
-        // For in-place decryption, we need to save ciphertext blocks
-        // before we overwrite them
         let mut prev_ciphertext = self.iv;
         
         for i in (0..data.len()).step_by(Self::BLOCK_SIZE) {
             let block = &mut data[i..i + Self::BLOCK_SIZE];
             
-            // Save current ciphertext before modifying
             let current_ciphertext: [u8; 16] = block.try_into().unwrap();
             
-            // Decrypt in-place
             let block_array: &mut [u8; 16] = block.try_into().unwrap();
             *block_array = self.decrypt_block(block_array, &key_schedule);
             
-            // XOR with previous ciphertext
             for j in 0..Self::BLOCK_SIZE {
                 block[j] ^= prev_ciphertext[j];
             }
             
-            // Save for next iteration
             prev_ciphertext = current_ciphertext;
         }
         
@@ -347,10 +346,8 @@ mod tests {
         let mut cipher = AesCtr::new(&key, iv);
         cipher.apply(&mut data);
         
-        // Encrypted should be different
         assert_ne!(&data[..], original);
         
-        // Decrypt with fresh cipher
         let mut cipher = AesCtr::new(&key, iv);
         cipher.apply(&mut data);
         
@@ -364,7 +361,7 @@ mod tests {
         let key = [0u8; 32];
         let iv = [0u8; 16];
         
-        let original = [0u8; 32]; // 2 blocks
+        let original = [0u8; 32];
         
         let cipher = AesCbc::new(key, iv);
         let encrypted = cipher.encrypt(&original).unwrap();
@@ -375,31 +372,25 @@ mod tests {
     
     #[test]
     fn test_aes_cbc_chaining_works() {
-        // This is the key test - verify CBC chaining is correct
         let key = [0x42u8; 32];
         let iv = [0x00u8; 16];
         
-        // Two IDENTICAL plaintext blocks
         let plaintext = [0xAAu8; 32];
         
         let cipher = AesCbc::new(key, iv);
         let ciphertext = cipher.encrypt(&plaintext).unwrap();
         
-        // With proper CBC, identical plaintext blocks produce DIFFERENT ciphertext
         let block1 = &ciphertext[0..16];
         let block2 = &ciphertext[16..32];
         
         assert_ne!(
             block1, block2,
-            "CBC chaining broken: identical plaintext blocks produced identical ciphertext. \
-             This indicates ECB mode, not CBC!"
+            "CBC chaining broken: identical plaintext blocks produced identical ciphertext"
         );
     }
     
     #[test]
     fn test_aes_cbc_known_vector() {
-        // Test with known NIST test vector
-        // AES-256-CBC with zero key and zero IV
         let key = [0u8; 32];
         let iv = [0u8; 16];
         let plaintext = [0u8; 16];
@@ -407,11 +398,9 @@ mod tests {
         let cipher = AesCbc::new(key, iv);
         let ciphertext = cipher.encrypt(&plaintext).unwrap();
         
-        // Decrypt and verify roundtrip
         let decrypted = cipher.decrypt(&ciphertext).unwrap();
         assert_eq!(plaintext.as_slice(), decrypted.as_slice());
         
-        // Ciphertext should not be all zeros
         assert_ne!(ciphertext.as_slice(), plaintext.as_slice());
     }
     
@@ -420,7 +409,6 @@ mod tests {
         let key = [0x12u8; 32];
         let iv = [0x34u8; 16];
         
-        // 5 blocks = 80 bytes
         let plaintext: Vec<u8> = (0..80).collect();
         
         let cipher = AesCbc::new(key, iv);
@@ -435,7 +423,7 @@ mod tests {
         let key = [0x12u8; 32];
         let iv = [0x34u8; 16];
         
-        let original = [0x56u8; 48]; // 3 blocks
+        let original = [0x56u8; 48];
         let mut buffer = original;
         
         let cipher = AesCbc::new(key, iv);
@@ -462,41 +450,33 @@ mod tests {
     fn test_aes_cbc_unaligned_error() {
         let cipher = AesCbc::new([0u8; 32], [0u8; 16]);
         
-        // 15 bytes - not aligned to block size
         let result = cipher.encrypt(&[0u8; 15]);
         assert!(result.is_err());
         
-        // 17 bytes - not aligned
         let result = cipher.encrypt(&[0u8; 17]);
         assert!(result.is_err());
     }
     
     #[test]
     fn test_aes_cbc_avalanche_effect() {
-        // Changing one bit in plaintext should change entire ciphertext block
-        // and all subsequent blocks (due to chaining)
         let key = [0xAB; 32];
         let iv = [0xCD; 16];
         
-        let mut plaintext1 = [0u8; 32];
+        let plaintext1 = [0u8; 32];
         let mut plaintext2 = [0u8; 32];
-        plaintext2[0] = 0x01; // Single bit difference in first block
+        plaintext2[0] = 0x01;
         
         let cipher = AesCbc::new(key, iv);
         
         let ciphertext1 = cipher.encrypt(&plaintext1).unwrap();
         let ciphertext2 = cipher.encrypt(&plaintext2).unwrap();
         
-        // First blocks should be different
         assert_ne!(&ciphertext1[0..16], &ciphertext2[0..16]);
-        
-        // Second blocks should ALSO be different (chaining effect)
         assert_ne!(&ciphertext1[16..32], &ciphertext2[16..32]);
     }
     
     #[test]
     fn test_aes_cbc_iv_matters() {
-        // Same plaintext with different IVs should produce different ciphertext
         let key = [0x55; 32];
         let plaintext = [0x77u8; 16];
         
@@ -511,7 +491,6 @@ mod tests {
     
     #[test]
     fn test_aes_cbc_deterministic() {
-        // Same key, IV, plaintext should always produce same ciphertext
         let key = [0x99; 32];
         let iv = [0x88; 16];
         let plaintext = [0x77u8; 32];
@@ -524,6 +503,23 @@ mod tests {
         assert_eq!(ciphertext1, ciphertext2);
     }
     
+    // ============= Zeroize Tests =============
+    
+    #[test]
+    fn test_aes_cbc_zeroize_on_drop() {
+        let key = [0xAA; 32];
+        let iv = [0xBB; 16];
+        
+        let cipher = AesCbc::new(key, iv);
+        // Verify key/iv are set
+        assert_eq!(cipher.key, [0xAA; 32]);
+        assert_eq!(cipher.iv, [0xBB; 16]);
+        
+        drop(cipher);
+        // After drop, key/iv are zeroized (can't observe directly,
+        // but the Drop impl runs without panic)
+    }
+    
     // ============= Error Handling Tests =============
     
     #[test]

src/crypto/hash.rs

@@ -1,3 +1,16 @@
+//! Cryptographic hash functions
+//!
+//! ## Protocol-required algorithms
+//!
+//! This module exposes MD5 and SHA-1 alongside SHA-256. These weaker
+//! hash functions are **required by the Telegram Middle Proxy protocol**
+//! (`derive_middleproxy_keys`) and cannot be replaced without breaking
+//! compatibility. They are NOT used for any security-sensitive purpose
+//! outside of that specific key derivation scheme mandated by Telegram.
+//!
+//! Static analysis tools (CodeQL, cargo-audit) may flag them — the
+//! usages are intentional and protocol-mandated.
+
 use hmac::{Hmac, Mac};
 use sha2::Sha256;
 use md5::Md5;
@@ -21,14 +34,16 @@ pub fn sha256_hmac(key: &[u8], data: &[u8]) -> [u8; 32] {
     mac.finalize().into_bytes().into()
 }
 
-/// SHA-1
+/// SHA-1 — **protocol-required** by Telegram Middle Proxy key derivation.
+/// Not used for general-purpose hashing.
 pub fn sha1(data: &[u8]) -> [u8; 20] {
     let mut hasher = Sha1::new();
     hasher.update(data);
     hasher.finalize().into()
 }
 
-/// MD5
+/// MD5 — **protocol-required** by Telegram Middle Proxy key derivation.
+/// Not used for general-purpose hashing.
 pub fn md5(data: &[u8]) -> [u8; 16] {
     let mut hasher = Md5::new();
     hasher.update(data);
@@ -40,7 +55,11 @@ pub fn crc32(data: &[u8]) -> u32 {
     crc32fast::hash(data)
 }
 
-/// Middle Proxy Keygen
+/// Middle Proxy key derivation
+///
+/// Uses MD5 + SHA-1 as mandated by the Telegram Middle Proxy protocol.
+/// These algorithms are NOT replaceable here — changing them would break
+/// interoperability with Telegram's middle proxy infrastructure.
 pub fn derive_middleproxy_keys(
     nonce_srv: &[u8; 16],
     nonce_clt: &[u8; 16],

src/crypto/mod.rs

@@ -6,4 +6,4 @@ pub mod random;
 
 pub use aes::{AesCtr, AesCbc};
 pub use hash::{sha256, sha256_hmac, sha1, md5, crc32};
-pub use random::{SecureRandom, SECURE_RANDOM};
+pub use random::SecureRandom;

src/crypto/random.rs

@@ -3,11 +3,8 @@
 use rand::{Rng, RngCore, SeedableRng};
 use rand::rngs::StdRng;
 use parking_lot::Mutex;
+use zeroize::Zeroize;
 use crate::crypto::AesCtr;
-use once_cell::sync::Lazy;
-
-/// Global secure random instance
-pub static SECURE_RANDOM: Lazy<SecureRandom> = Lazy::new(SecureRandom::new);
 
 /// Cryptographically secure PRNG with AES-CTR
 pub struct SecureRandom {
@@ -20,18 +17,30 @@ struct SecureRandomInner {
     buffer: Vec<u8>,
 }
 
+impl Drop for SecureRandomInner {
+    fn drop(&mut self) {
+        self.buffer.zeroize();
+    }
+}
+
 impl SecureRandom {
     pub fn new() -> Self {
-        let mut rng = StdRng::from_entropy();
+        let mut seed_source = rand::rng();
+        let mut rng = StdRng::from_rng(&mut seed_source);
         
         let mut key = [0u8; 32];
         rng.fill_bytes(&mut key);
-        let iv: u128 = rng.gen();
+        let iv: u128 = rng.random();
+        
+        let cipher = AesCtr::new(&key, iv);
+        
+        // Zeroize local key copy — cipher already consumed it
+        key.zeroize();
         
         Self {
             inner: Mutex::new(SecureRandomInner {
                 rng,
-                cipher: AesCtr::new(&key, iv),
+                cipher,
                 buffer: Vec::with_capacity(1024),
             }),
         }
@@ -78,7 +87,6 @@ impl SecureRandom {
             result |= (b as u64) << (i * 8);
         }
         
-        // Mask extra bits
         if k < 64 {
             result &= (1u64 << k) - 1;
         }
@@ -107,13 +115,13 @@ impl SecureRandom {
     /// Generate random u32
     pub fn u32(&self) -> u32 {
         let mut inner = self.inner.lock();
-        inner.rng.gen()
+        inner.rng.random()
     }
     
     /// Generate random u64
     pub fn u64(&self) -> u64 {
         let mut inner = self.inner.lock();
-        inner.rng.gen()
+        inner.rng.random()
     }
 }
 
@@ -162,12 +170,10 @@ mod tests {
     fn test_bits() {
         let rng = SecureRandom::new();
         
-        // Single bit should be 0 or 1
         for _ in 0..100 {
             assert!(rng.bits(1) <= 1);
         }
         
-        // 8 bits should be 0-255
         for _ in 0..100 {
             assert!(rng.bits(8) <= 255);
         }
@@ -185,10 +191,8 @@ mod tests {
             }
         }
         
-        // Should have seen all items
         assert_eq!(seen.len(), 5);
         
-        // Empty slice should return None
         let empty: Vec<i32> = vec![];
         assert!(rng.choose(&empty).is_none());
     }
@@ -201,12 +205,10 @@ mod tests {
         let mut shuffled = original.clone();
         rng.shuffle(&mut shuffled);
         
-        // Should contain same elements
         let mut sorted = shuffled.clone();
         sorted.sort();
         assert_eq!(sorted, original);
         
-        // Should be different order (with very high probability)
         assert_ne!(shuffled, original);
     }
 }

src/error.rs

@@ -118,16 +118,13 @@ pub trait Recoverable {
 impl Recoverable for StreamError {
     fn is_recoverable(&self) -> bool {
         match self {
-            // Partial operations can be retried
             Self::PartialRead { .. } | Self::PartialWrite { .. } => true,
-            // I/O errors depend on kind
             Self::Io(e) => matches!(
                 e.kind(),
                 std::io::ErrorKind::WouldBlock 
                 | std::io::ErrorKind::Interrupted
                 | std::io::ErrorKind::TimedOut
             ),
-            // These are not recoverable
             Self::Poisoned { .. } 
             | Self::BufferOverflow { .. }
             | Self::InvalidFrame { .. }
@@ -137,13 +134,9 @@ impl Recoverable for StreamError {
     
     fn can_continue(&self) -> bool {
         match self {
-            // Poisoned stream cannot be used
             Self::Poisoned { .. } => false,
-            // EOF means stream is done
             Self::UnexpectedEof => false,
-            // Buffer overflow is fatal
             Self::BufferOverflow { .. } => false,
-            // Others might allow continuation
             _ => true,
         }
     }
@@ -383,18 +376,18 @@ mod tests {
     
     #[test]
     fn test_handshake_result() {
-        let success: HandshakeResult<i32> = HandshakeResult::Success(42);
+        let success: HandshakeResult<i32, (), ()> = HandshakeResult::Success(42);
         assert!(success.is_success());
         assert!(!success.is_bad_client());
         
-        let bad: HandshakeResult<i32> = HandshakeResult::BadClient;
+        let bad: HandshakeResult<i32, (), ()> = HandshakeResult::BadClient { reader: (), writer: () };
         assert!(!bad.is_success());
         assert!(bad.is_bad_client());
     }
     
     #[test]
     fn test_handshake_result_map() {
-        let success: HandshakeResult<i32> = HandshakeResult::Success(42);
+        let success: HandshakeResult<i32, (), ()> = HandshakeResult::Success(42);
         let mapped = success.map(|x| x * 2);
         
         match mapped {

src/main.rs

@@ -5,9 +5,11 @@ use std::sync::Arc;
 use std::time::Duration;
 use tokio::net::TcpListener;
 use tokio::signal;
-use tracing::{info, error, warn};
-use tracing_subscriber::{fmt, EnvFilter};
+use tokio::sync::Semaphore;
+use tracing::{info, error, warn, debug};
+use tracing_subscriber::{fmt, EnvFilter, reload, prelude::*};
 
+mod cli;
 mod config;
 mod crypto;
 mod error;
@@ -18,78 +20,174 @@ mod stream;
 mod transport;
 mod util;
 
-use crate::config::ProxyConfig;
+use crate::config::{ProxyConfig, LogLevel};
 use crate::proxy::ClientHandler;
 use crate::stats::{Stats, ReplayChecker};
+use crate::crypto::SecureRandom;
 use crate::transport::{create_listener, ListenOptions, UpstreamManager};
 use crate::util::ip::detect_ip;
 use crate::stream::BufferPool;
 
+fn parse_cli() -> (String, bool, Option<String>) {
+    let mut config_path = "config.toml".to_string();
+    let mut silent = false;
+    let mut log_level: Option<String> = None;
+    
+    let args: Vec<String> = std::env::args().skip(1).collect();
+    
+    // Check for --init first (handled before tokio)
+    if let Some(init_opts) = cli::parse_init_args(&args) {
+        if let Err(e) = cli::run_init(init_opts) {
+            eprintln!("[telemt] Init failed: {}", e);
+            std::process::exit(1);
+        }
+        std::process::exit(0);
+    }
+    
+    let mut i = 0;
+    while i < args.len() {
+        match args[i].as_str() {
+            "--silent" | "-s" => { silent = true; }
+            "--log-level" => {
+                i += 1;
+                if i < args.len() { log_level = Some(args[i].clone()); }
+            }
+            s if s.starts_with("--log-level=") => {
+                log_level = Some(s.trim_start_matches("--log-level=").to_string());
+            }
+            "--help" | "-h" => {
+                eprintln!("Usage: telemt [config.toml] [OPTIONS]");
+                eprintln!();
+                eprintln!("Options:");
+                eprintln!("  --silent, -s            Suppress info logs");
+                eprintln!("  --log-level <LEVEL>     debug|verbose|normal|silent");
+                eprintln!("  --help, -h              Show this help");
+                eprintln!();
+                eprintln!("Setup (fire-and-forget):");
+                eprintln!("  --init                  Generate config, install systemd service, start");
+                eprintln!("    --port <PORT>          Listen port (default: 443)");
+                eprintln!("    --domain <DOMAIN>      TLS domain for masking (default: www.google.com)");
+                eprintln!("    --secret <HEX>         32-char hex secret (auto-generated if omitted)");
+                eprintln!("    --user <NAME>          Username (default: user)");
+                eprintln!("    --config-dir <DIR>     Config directory (default: /etc/telemt)");
+                eprintln!("    --no-start             Don't start the service after install");
+                std::process::exit(0);
+            }
+            s if !s.starts_with('-') => { config_path = s.to_string(); }
+            other => { eprintln!("Unknown option: {}", other); }
+        }
+        i += 1;
+    }
+    
+    (config_path, silent, log_level)
+}
+
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    // Initialize logging
-    fmt()
-        .with_env_filter(EnvFilter::from_default_env().add_directive("info".parse().unwrap()))
-        .init();
+    let (config_path, cli_silent, cli_log_level) = parse_cli();
 
-    // Load config
-    let config_path = std::env::args().nth(1).unwrap_or_else(|| "config.toml".to_string());
     let config = match ProxyConfig::load(&config_path) {
         Ok(c) => c,
         Err(e) => {
-            // If config doesn't exist, try to create default
             if std::path::Path::new(&config_path).exists() {
-                error!("Failed to load config: {}", e);
+                eprintln!("[telemt] Error: {}", e);
                 std::process::exit(1);
             } else {
                 let default = ProxyConfig::default();
-                let toml = toml::to_string_pretty(&default).unwrap();
-                std::fs::write(&config_path, toml).unwrap();
-                info!("Created default config at {}", config_path);
+                std::fs::write(&config_path, toml::to_string_pretty(&default).unwrap()).unwrap();
+                eprintln!("[telemt] Created default config at {}", config_path);
                 default
             }
         }
     };
     
-    config.validate()?;
+    if let Err(e) = config.validate() {
+        eprintln!("[telemt] Invalid config: {}", e);
+        std::process::exit(1);
+    }
 
-    // Log loaded configuration for debugging
-    info!("=== Configuration Loaded ===");
-    info!("TLS Domain: {}", config.censorship.tls_domain);
-    info!("Mask enabled: {}", config.censorship.mask);
-    info!("Mask host: {}", config.censorship.mask_host.as_deref().unwrap_or(&config.censorship.tls_domain));
-    info!("Mask port: {}", config.censorship.mask_port);
-    info!("Modes: classic={}, secure={}, tls={}", 
+    let has_rust_log = std::env::var("RUST_LOG").is_ok();
+    let effective_log_level = if cli_silent {
+        LogLevel::Silent
+    } else if let Some(ref s) = cli_log_level {
+        LogLevel::from_str_loose(s)
+    } else {
+        config.general.log_level.clone()
+    };
+
+    // Start with INFO so startup messages are always visible,
+    // then switch to user-configured level after startup
+    let (filter_layer, filter_handle) = reload::Layer::new(EnvFilter::new("info"));
+    tracing_subscriber::registry()
+        .with(filter_layer)
+        .with(fmt::Layer::default())
+        .init();
+
+    info!("Telemt MTProxy v{}", env!("CARGO_PKG_VERSION"));
+    info!("Log level: {}", effective_log_level);
+    info!("Modes: classic={} secure={} tls={}",
         config.general.modes.classic,
         config.general.modes.secure,
-        config.general.modes.tls
-    );
-    info!("============================");
+        config.general.modes.tls);
+    info!("TLS domain: {}", config.censorship.tls_domain);
+    info!("Mask: {} -> {}:{}",
+        config.censorship.mask,
+        config.censorship.mask_host.as_deref().unwrap_or(&config.censorship.tls_domain),
+        config.censorship.mask_port);
 
+    if config.censorship.tls_domain == "www.google.com" {
+        warn!("Using default tls_domain. Consider setting a custom domain.");
+    }
+    
+    let prefer_ipv6 = config.general.prefer_ipv6;
     let config = Arc::new(config);
     let stats = Arc::new(Stats::new());
+    let rng = Arc::new(SecureRandom::new());
     
-    // Initialize global ReplayChecker
-    // Using sharded implementation for better concurrency
-    let replay_checker = Arc::new(ReplayChecker::new(config.access.replay_check_len));
+    let replay_checker = Arc::new(ReplayChecker::new(
+        config.access.replay_check_len,
+        Duration::from_secs(config.access.replay_window_secs),
+    ));
     
-    // Initialize Upstream Manager
     let upstream_manager = Arc::new(UpstreamManager::new(config.upstreams.clone()));
-    
-    // Initialize Buffer Pool
-    // 16KB buffers, max 4096 buffers (~64MB total cached)
     let buffer_pool = Arc::new(BufferPool::with_config(16 * 1024, 4096));
     
-    // Start Health Checks
+        // Connection concurrency limit — prevents OOM under SYN flood / connection storm.
+        // 10000 is generous; each connection uses ~64KB (2x 16KB relay buffers + overhead).
+        // 10000 connections ≈ 640MB peak memory.
+        let max_connections = Arc::new(Semaphore::new(10_000));
+    
+    // Startup DC ping
+    info!("=== Telegram DC Connectivity ===");
+    let ping_results = upstream_manager.ping_all_dcs(prefer_ipv6).await;
+    for upstream_result in &ping_results {
+        info!("  via {}", upstream_result.upstream_name);
+        for dc in &upstream_result.results {
+            match (&dc.rtt_ms, &dc.error) {
+                (Some(rtt), _) => {
+                    info!("    DC{} ({:>21}):  {:.0}ms", dc.dc_idx, dc.dc_addr, rtt);
+                }
+                (None, Some(err)) => {
+                    info!("    DC{} ({:>21}):  FAIL ({})", dc.dc_idx, dc.dc_addr, err);
+                }
+                _ => {
+                    info!("    DC{} ({:>21}):  FAIL", dc.dc_idx, dc.dc_addr);
+                }
+            }
+        }
+    }
+    info!("================================");
+    
+    // Background tasks
     let um_clone = upstream_manager.clone();
-    tokio::spawn(async move {
-        um_clone.run_health_checks().await;
-    });
+    tokio::spawn(async move { um_clone.run_health_checks(prefer_ipv6).await; });
+    
+    let rc_clone = replay_checker.clone();
+    tokio::spawn(async move { rc_clone.run_periodic_cleanup().await; });
 
-    // Detect public IP if needed (once at startup)
     let detected_ip = detect_ip().await;
+    debug!("Detected IPs: v4={:?} v6={:?}", detected_ip.ipv4, detected_ip.ipv6);
 
-    // Start Listeners
     let mut listeners = Vec::new();
     
     for listener_conf in &config.server.listeners {
@@ -104,7 +202,6 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                 let listener = TcpListener::from_std(socket.into())?;
                 info!("Listening on {}", addr);
                 
-                // Determine public IP for tg:// links
                 let public_ip = if let Some(ip) = listener_conf.announce_ip {
                     ip
                 } else if listener_conf.ip.is_unspecified() {
@@ -117,33 +214,29 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                     listener_conf.ip
                 };
 
-                // Show links for configured users
                 if !config.show_link.is_empty() {
-                    info!("--- Proxy Links for {} ---", public_ip);
+                    info!("--- Proxy Links ({}) ---", public_ip);
                     for user_name in &config.show_link {
                         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={}",
                                     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 '{}' specified in show_link not found in users list", user_name);
+                            warn!("User '{}' in show_link not found", user_name);
                         }
                     }
-                    info!("-----------------------------------");
+                    info!("------------------------");
                 }
                 
                 listeners.push(listener);
@@ -155,17 +248,25 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     }
     
     if listeners.is_empty() {
-        error!("No listeners could be started. Exiting.");
+        error!("No listeners. Exiting.");
         std::process::exit(1);
     }
 
-    // Accept loop
+    // Switch to user-configured log level after startup
+    let runtime_filter = if has_rust_log {
+        EnvFilter::from_default_env()
+    } else {
+        EnvFilter::new(effective_log_level.to_filter_str())
+    };
+    filter_handle.reload(runtime_filter).expect("Failed to switch log filter");
+
     for listener in listeners {
         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();
         
         tokio::spawn(async move {
             loop {
@@ -176,18 +277,14 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                         let upstream_manager = upstream_manager.clone();
                         let replay_checker = replay_checker.clone();
                         let buffer_pool = buffer_pool.clone();
+                        let rng = rng.clone();
                         
                         tokio::spawn(async move {
                             if let Err(e) = ClientHandler::new(
-                                stream, 
-                                peer_addr, 
-                                config, 
-                                stats,
-                                upstream_manager,
-                                replay_checker,
-                                buffer_pool
+                                stream, peer_addr, config, stats,
+                                upstream_manager, replay_checker, buffer_pool, rng
                             ).run().await {
-                                // Log only relevant errors
+                                debug!(peer = %peer_addr, error = %e, "Connection error");
                             }
                         });
                     }
@@ -200,7 +297,6 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         });
     }
 
-    // Wait for signal
     match signal::ctrl_c().await {
         Ok(()) => info!("Shutting down..."),
         Err(e) => error!("Signal error: {}", e),

src/protocol/constants.rs

@@ -1,13 +1,13 @@
 //! Protocol constants and datacenter addresses
 
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
-use once_cell::sync::Lazy;
+use std::sync::LazyLock;
 
 // ============= Telegram Datacenters =============
 
 pub const TG_DATACENTER_PORT: u16 = 443;
 
-pub static TG_DATACENTERS_V4: Lazy<Vec<IpAddr>> = Lazy::new(|| {
+pub static TG_DATACENTERS_V4: LazyLock<Vec<IpAddr>> = LazyLock::new(|| {
     vec![
         IpAddr::V4(Ipv4Addr::new(149, 154, 175, 50)),
         IpAddr::V4(Ipv4Addr::new(149, 154, 167, 51)),
@@ -17,7 +17,7 @@ pub static TG_DATACENTERS_V4: Lazy<Vec<IpAddr>> = Lazy::new(|| {
     ]
 });
 
-pub static TG_DATACENTERS_V6: Lazy<Vec<IpAddr>> = Lazy::new(|| {
+pub static TG_DATACENTERS_V6: LazyLock<Vec<IpAddr>> = LazyLock::new(|| {
     vec![
         IpAddr::V6("2001:b28:f23d:f001::a".parse().unwrap()),
         IpAddr::V6("2001:67c:04e8:f002::a".parse().unwrap()),
@@ -29,8 +29,8 @@ pub static TG_DATACENTERS_V6: Lazy<Vec<IpAddr>> = Lazy::new(|| {
 
 // ============= Middle Proxies (for advertising) =============
 
-pub static TG_MIDDLE_PROXIES_V4: Lazy<std::collections::HashMap<i32, Vec<(IpAddr, u16)>>> = 
-    Lazy::new(|| {
+pub static TG_MIDDLE_PROXIES_V4: LazyLock<std::collections::HashMap<i32, Vec<(IpAddr, u16)>>> = 
+    LazyLock::new(|| {
         let mut m = std::collections::HashMap::new();
         m.insert(1, vec![(IpAddr::V4(Ipv4Addr::new(149, 154, 175, 50)), 8888)]);
         m.insert(-1, vec![(IpAddr::V4(Ipv4Addr::new(149, 154, 175, 50)), 8888)]);
@@ -45,8 +45,8 @@ pub static TG_MIDDLE_PROXIES_V4: Lazy<std::collections::HashMap<i32, Vec<(IpAddr
         m
     });
 
-pub static TG_MIDDLE_PROXIES_V6: Lazy<std::collections::HashMap<i32, Vec<(IpAddr, u16)>>> = 
-    Lazy::new(|| {
+pub static TG_MIDDLE_PROXIES_V6: LazyLock<std::collections::HashMap<i32, Vec<(IpAddr, u16)>>> = 
+    LazyLock::new(|| {
         let mut m = std::collections::HashMap::new();
         m.insert(1, vec![(IpAddr::V6("2001:b28:f23d:f001::d".parse().unwrap()), 8888)]);
         m.insert(-1, vec![(IpAddr::V6("2001:b28:f23d:f001::d".parse().unwrap()), 8888)]);
@@ -167,8 +167,6 @@ pub const DEFAULT_ACK_TIMEOUT_SECS: u64 = 300;
 // ============= Buffer Sizes =============
 
 /// Default buffer size
-/// CHANGED: Reduced from 64KB to 16KB to match TLS record size and align with
-/// the new buffering strategy for better iOS upload performance.
 pub const DEFAULT_BUFFER_SIZE: usize = 16384;
 
 /// Small buffer size for bad client handling

src/protocol/obfuscation.rs

@@ -1,10 +1,13 @@
 //! MTProto Obfuscation
 
+use zeroize::Zeroize;
 use crate::crypto::{sha256, AesCtr};
 use crate::error::Result;
 use super::constants::*;
 
 /// Obfuscation parameters from handshake
+///
+/// Key material is zeroized on drop.
 #[derive(Debug, Clone)]
 pub struct ObfuscationParams {
     /// Key for decrypting client -> proxy traffic
@@ -21,25 +24,31 @@ pub struct ObfuscationParams {
     pub dc_idx: i16,
 }
 
+impl Drop for ObfuscationParams {
+    fn drop(&mut self) {
+        self.decrypt_key.zeroize();
+        self.decrypt_iv.zeroize();
+        self.encrypt_key.zeroize();
+        self.encrypt_iv.zeroize();
+    }
+}
+
 impl ObfuscationParams {
     /// Parse obfuscation parameters from handshake bytes
     /// Returns None if handshake doesn't match any user secret
     pub fn from_handshake(
         handshake: &[u8; HANDSHAKE_LEN],
-        secrets: &[(String, Vec<u8>)], // (username, secret_bytes)
+        secrets: &[(String, Vec<u8>)],
     ) -> Option<(Self, String)> {
-        // Extract prekey and IV for decryption
         let dec_prekey_iv = &handshake[SKIP_LEN..SKIP_LEN + PREKEY_LEN + IV_LEN];
         let dec_prekey = &dec_prekey_iv[..PREKEY_LEN];
         let dec_iv_bytes = &dec_prekey_iv[PREKEY_LEN..];
         
-        // Reversed for encryption direction
         let enc_prekey_iv: Vec<u8> = dec_prekey_iv.iter().rev().copied().collect();
         let enc_prekey = &enc_prekey_iv[..PREKEY_LEN];
         let enc_iv_bytes = &enc_prekey_iv[PREKEY_LEN..];
         
         for (username, secret) in secrets {
-            // Derive decryption key
             let mut dec_key_input = Vec::with_capacity(PREKEY_LEN + secret.len());
             dec_key_input.extend_from_slice(dec_prekey);
             dec_key_input.extend_from_slice(secret);
@@ -47,26 +56,22 @@ impl ObfuscationParams {
             
             let decrypt_iv = u128::from_be_bytes(dec_iv_bytes.try_into().unwrap());
             
-            // Create decryptor and decrypt handshake
             let mut decryptor = AesCtr::new(&decrypt_key, decrypt_iv);
             let decrypted = decryptor.decrypt(handshake);
             
-            // Check protocol tag
             let tag_bytes: [u8; 4] = decrypted[PROTO_TAG_POS..PROTO_TAG_POS + 4]
                 .try_into()
                 .unwrap();
             
             let proto_tag = match ProtoTag::from_bytes(tag_bytes) {
                 Some(tag) => tag,
-                None => continue, // Try next secret
+                None => continue,
             };
             
-            // Extract DC index
             let dc_idx = i16::from_le_bytes(
                 decrypted[DC_IDX_POS..DC_IDX_POS + 2].try_into().unwrap()
             );
             
-            // Derive encryption key
             let mut enc_key_input = Vec::with_capacity(PREKEY_LEN + secret.len());
             enc_key_input.extend_from_slice(enc_prekey);
             enc_key_input.extend_from_slice(secret);
@@ -123,18 +128,15 @@ pub fn generate_nonce<R: FnMut(usize) -> Vec<u8>>(mut random_bytes: R) -> [u8; H
 
 /// Check if nonce is valid (not matching reserved patterns)
 pub fn is_valid_nonce(nonce: &[u8; HANDSHAKE_LEN]) -> bool {
-    // Check first byte
     if RESERVED_NONCE_FIRST_BYTES.contains(&nonce[0]) {
         return false;
     }
     
-    // Check first 4 bytes
     let first_four: [u8; 4] = nonce[..4].try_into().unwrap();
     if RESERVED_NONCE_BEGINNINGS.contains(&first_four) {
         return false;
     }
     
-    // Check bytes 4-7
     let continue_four: [u8; 4] = nonce[4..8].try_into().unwrap();
     if RESERVED_NONCE_CONTINUES.contains(&continue_four) {
         return false;
@@ -147,12 +149,10 @@ pub fn is_valid_nonce(nonce: &[u8; HANDSHAKE_LEN]) -> bool {
 pub fn prepare_tg_nonce(
     nonce: &mut [u8; HANDSHAKE_LEN],
     proto_tag: ProtoTag,
-    enc_key_iv: Option<&[u8]>, // For fast mode
+    enc_key_iv: Option<&[u8]>,
 ) {
-    // Set protocol tag
     nonce[PROTO_TAG_POS..PROTO_TAG_POS + 4].copy_from_slice(&proto_tag.to_bytes());
     
-    // For fast mode, copy the reversed enc_key_iv
     if let Some(key_iv) = enc_key_iv {
         let reversed: Vec<u8> = key_iv.iter().rev().copied().collect();
         nonce[SKIP_LEN..SKIP_LEN + KEY_LEN + IV_LEN].copy_from_slice(&reversed);
@@ -161,14 +161,12 @@ pub fn prepare_tg_nonce(
 
 /// Encrypt the outgoing nonce for Telegram
 pub fn encrypt_nonce(nonce: &[u8; HANDSHAKE_LEN]) -> Vec<u8> {
-    // Derive encryption key from the nonce itself
     let key_iv = &nonce[SKIP_LEN..SKIP_LEN + KEY_LEN + IV_LEN];
     let enc_key = sha256(key_iv);
     let enc_iv = u128::from_be_bytes(key_iv[..IV_LEN].try_into().unwrap());
     
     let mut encryptor = AesCtr::new(&enc_key, enc_iv);
     
-    // Only encrypt from PROTO_TAG_POS onwards
     let mut result = nonce.to_vec();
     let encrypted_part = encryptor.encrypt(&nonce[PROTO_TAG_POS..]);
     result[PROTO_TAG_POS..].copy_from_slice(&encrypted_part);
@@ -182,22 +180,18 @@ mod tests {
     
     #[test]
     fn test_is_valid_nonce() {
-        // Valid nonce
         let mut valid = [0x42u8; HANDSHAKE_LEN];
         valid[4..8].copy_from_slice(&[1, 2, 3, 4]);
         assert!(is_valid_nonce(&valid));
         
-        // Invalid: starts with 0xef
         let mut invalid = [0x00u8; HANDSHAKE_LEN];
         invalid[0] = 0xef;
         assert!(!is_valid_nonce(&invalid));
         
-        // Invalid: starts with HEAD
         let mut invalid = [0x00u8; HANDSHAKE_LEN];
         invalid[..4].copy_from_slice(b"HEAD");
         assert!(!is_valid_nonce(&invalid));
         
-        // Invalid: bytes 4-7 are zeros
         let mut invalid = [0x42u8; HANDSHAKE_LEN];
         invalid[4..8].copy_from_slice(&[0, 0, 0, 0]);
         assert!(!is_valid_nonce(&invalid));

src/protocol/tls.rs

@@ -4,7 +4,7 @@
 //! for domain fronting. The handshake looks like valid TLS 1.3 but
 //! actually carries MTProto authentication data.
 
-use crate::crypto::{sha256_hmac, random::SECURE_RANDOM};
+use crate::crypto::{sha256_hmac, SecureRandom};
 use crate::error::{ProxyError, Result};
 use super::constants::*;
 use std::time::{SystemTime, UNIX_EPOCH};
@@ -315,8 +315,8 @@ pub fn validate_tls_handshake(
 ///
 /// This generates random bytes that look like a valid X25519 public key.
 /// Since we're not doing real TLS, the actual cryptographic properties don't matter.
-pub fn gen_fake_x25519_key() -> [u8; 32] {
-    let bytes = SECURE_RANDOM.bytes(32);
+pub fn gen_fake_x25519_key(rng: &SecureRandom) -> [u8; 32] {
+    let bytes = rng.bytes(32);
     bytes.try_into().unwrap()
 }
 
@@ -333,8 +333,9 @@ pub fn build_server_hello(
     client_digest: &[u8; TLS_DIGEST_LEN],
     session_id: &[u8],
     fake_cert_len: usize,
+    rng: &SecureRandom,
 ) -> Vec<u8> {
-    let x25519_key = gen_fake_x25519_key();
+    let x25519_key = gen_fake_x25519_key(rng);
     
     // Build ServerHello
     let server_hello = ServerHelloBuilder::new(session_id.to_vec())
@@ -351,7 +352,7 @@ pub fn build_server_hello(
     ];
     
     // Build fake certificate (Application Data record)
-    let fake_cert = SECURE_RANDOM.bytes(fake_cert_len);
+    let fake_cert = rng.bytes(fake_cert_len);
     let mut app_data_record = Vec::with_capacity(5 + fake_cert_len);
     app_data_record.push(TLS_RECORD_APPLICATION);
     app_data_record.extend_from_slice(&TLS_VERSION);
@@ -489,8 +490,9 @@ mod tests {
     
     #[test]
     fn test_gen_fake_x25519_key() {
-        let key1 = gen_fake_x25519_key();
-        let key2 = gen_fake_x25519_key();
+        let rng = SecureRandom::new();
+        let key1 = gen_fake_x25519_key(&rng);
+        let key2 = gen_fake_x25519_key(&rng);
         
         assert_eq!(key1.len(), 32);
         assert_eq!(key2.len(), 32);
@@ -545,7 +547,8 @@ mod tests {
         let client_digest = [0x42u8; 32];
         let session_id = vec![0xAA; 32];
         
-        let response = build_server_hello(secret, &client_digest, &session_id, 2048);
+        let rng = SecureRandom::new();
+        let response = build_server_hello(secret, &client_digest, &session_id, 2048, &rng);
         
         // Should have at least 3 records
         assert!(response.len() > 100);
@@ -577,8 +580,9 @@ mod tests {
         let client_digest = [0x42u8; 32];
         let session_id = vec![0xAA; 32];
         
-        let response1 = build_server_hello(secret, &client_digest, &session_id, 1024);
-        let response2 = build_server_hello(secret, &client_digest, &session_id, 1024);
+        let rng = SecureRandom::new();
+        let response1 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng);
+        let response2 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng);
         
         // Digest position should have non-zero data
         let digest1 = &response1[TLS_DIGEST_POS..TLS_DIGEST_POS + TLS_DIGEST_LEN];

src/proxy/client.rs

@@ -15,9 +15,8 @@ use crate::protocol::tls;
 use crate::stats::{Stats, ReplayChecker};
 use crate::transport::{configure_client_socket, UpstreamManager};
 use crate::stream::{CryptoReader, CryptoWriter, FakeTlsReader, FakeTlsWriter, BufferPool};
-use crate::crypto::AesCtr;
+use crate::crypto::{AesCtr, SecureRandom};
 
-// Use absolute paths to avoid confusion
 use crate::proxy::handshake::{
     handle_tls_handshake, handle_mtproto_handshake, 
     HandshakeSuccess, generate_tg_nonce, encrypt_tg_nonce,
@@ -25,10 +24,8 @@ use crate::proxy::handshake::{
 use crate::proxy::relay::relay_bidirectional;
 use crate::proxy::masking::handle_bad_client;
 
-/// Client connection handler (builder struct)
 pub struct ClientHandler;
 
-/// Running client handler with stream and context
 pub struct RunningClientHandler {
     stream: TcpStream,
     peer: SocketAddr,
@@ -37,10 +34,10 @@ pub struct RunningClientHandler {
     replay_checker: Arc<ReplayChecker>,
     upstream_manager: Arc<UpstreamManager>,
     buffer_pool: Arc<BufferPool>,
+    rng: Arc<SecureRandom>,
 }
 
 impl ClientHandler {
-    /// Create new client handler instance
     pub fn new(
         stream: TcpStream,
         peer: SocketAddr,
@@ -49,28 +46,22 @@ impl ClientHandler {
         upstream_manager: Arc<UpstreamManager>,
         replay_checker: Arc<ReplayChecker>,
         buffer_pool: Arc<BufferPool>,
+        rng: Arc<SecureRandom>,
     ) -> RunningClientHandler {
         RunningClientHandler {
-            stream,
-            peer,
-            config,
-            stats,
-            replay_checker,
-            upstream_manager,
-            buffer_pool,
+            stream, peer, config, stats, replay_checker,
+            upstream_manager, buffer_pool, rng,
         }
     }
 }
 
 impl RunningClientHandler {
-    /// Run the client handler
     pub async fn run(mut self) -> Result<()> {
         self.stats.increment_connects_all();
         
         let peer = self.peer;
         debug!(peer = %peer, "New connection");
         
-        // Configure socket
         if let Err(e) = configure_client_socket(
             &self.stream,
             self.config.timeouts.client_keepalive,
@@ -79,16 +70,10 @@ impl RunningClientHandler {
             debug!(peer = %peer, error = %e, "Failed to configure client socket");
         }
         
-        // Perform handshake with timeout
         let handshake_timeout = Duration::from_secs(self.config.timeouts.client_handshake);
-        
-        // Clone stats for error handling block
         let stats = self.stats.clone();
         
-        let result = timeout(
-            handshake_timeout,
-            self.do_handshake()
-        ).await;
+        let result = timeout(handshake_timeout, self.do_handshake()).await;
         
         match result {
             Ok(Ok(())) => {
@@ -107,16 +92,14 @@ impl RunningClientHandler {
         }
     }
     
-    /// Perform handshake and relay
     async fn do_handshake(mut self) -> Result<()> {
-        // Read first bytes to determine handshake type
         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;
         
-        debug!(peer = %peer, is_tls = is_tls, first_bytes = %hex::encode(&first_bytes), "Handshake type detected");
+        debug!(peer = %peer, is_tls = is_tls, "Handshake type detected");
         
         if is_tls {
             self.handle_tls_client(first_bytes).await
@@ -125,14 +108,9 @@ impl RunningClientHandler {
         }
     }
     
-    /// Handle TLS-wrapped client
-    async fn handle_tls_client(
-        mut self,
-        first_bytes: [u8; 5],
-    ) -> Result<()> {
+    async fn handle_tls_client(mut self, first_bytes: [u8; 5]) -> Result<()> {
         let peer = self.peer;
         
-        // Read TLS handshake length
         let tls_len = u16::from_be_bytes([first_bytes[3], first_bytes[4]]) as usize;
         
         debug!(peer = %peer, tls_len = tls_len, "Reading TLS handshake");
@@ -140,34 +118,25 @@ impl RunningClientHandler {
         if tls_len < 512 {
             debug!(peer = %peer, tls_len = tls_len, "TLS handshake too short");
             self.stats.increment_connects_bad();
-            // FIX: Split stream into reader/writer for handle_bad_client
             let (reader, writer) = self.stream.into_split();
             handle_bad_client(reader, writer, &first_bytes, &self.config).await;
             return Ok(());
         }
         
-        // Read full TLS handshake
         let mut handshake = vec![0u8; 5 + tls_len];
         handshake[..5].copy_from_slice(&first_bytes);
         self.stream.read_exact(&mut handshake[5..]).await?;
         
-        // Extract fields before consuming self.stream
         let config = self.config.clone();
         let replay_checker = self.replay_checker.clone();
         let stats = self.stats.clone();
         let buffer_pool = self.buffer_pool.clone();
         
-        // Split stream for reading/writing
         let (read_half, write_half) = self.stream.into_split();
         
-        // Handle TLS handshake
         let (mut tls_reader, tls_writer, _tls_user) = match handle_tls_handshake(
-            &handshake,
-            read_half,
-            write_half,
-            peer,
-            &config,
-            &replay_checker,
+            &handshake, read_half, write_half, peer,
+            &config, &replay_checker, &self.rng,
         ).await {
             HandshakeResult::Success(result) => result,
             HandshakeResult::BadClient { reader, writer } => {
@@ -178,83 +147,56 @@ impl RunningClientHandler {
             HandshakeResult::Error(e) => return Err(e),
         };
         
-        // Read MTProto handshake through TLS
         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()))?;
         
-        // Handle MTProto handshake
         let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
-            &mtproto_handshake,
-            tls_reader,
-            tls_writer,
-            peer,
-            &config,
-            &replay_checker,
-            true,
+            &mtproto_handshake, tls_reader, tls_writer, peer,
+            &config, &replay_checker, true,
         ).await {
             HandshakeResult::Success(result) => result,
-            HandshakeResult::BadClient { reader, writer } => {
+            HandshakeResult::BadClient { reader: _, writer: _ } => {
                 stats.increment_connects_bad();
-                // Valid TLS but invalid MTProto - drop
-                debug!(peer = %peer, "Valid TLS but invalid MTProto handshake - dropping");
+                debug!(peer = %peer, "Valid TLS but invalid MTProto handshake");
                 return Ok(());
             }
             HandshakeResult::Error(e) => return Err(e),
         };
         
         Self::handle_authenticated_static(
-            crypto_reader, 
-            crypto_writer, 
-            success, 
-            self.upstream_manager, 
-            self.stats, 
-            self.config,
-            buffer_pool
+            crypto_reader, crypto_writer, success,
+            self.upstream_manager, self.stats, self.config,
+            buffer_pool, self.rng,
         ).await
     }
     
-    /// Handle direct (non-TLS) client
-    async fn handle_direct_client(
-        mut self,
-        first_bytes: [u8; 5],
-    ) -> Result<()> {
+    async fn handle_direct_client(mut self, first_bytes: [u8; 5]) -> Result<()> {
         let peer = self.peer;
         
-        // Check if non-TLS modes are enabled
         if !self.config.general.modes.classic && !self.config.general.modes.secure {
             debug!(peer = %peer, "Non-TLS modes disabled");
             self.stats.increment_connects_bad();
-            // FIX: Split stream into reader/writer for handle_bad_client
             let (reader, writer) = self.stream.into_split();
             handle_bad_client(reader, writer, &first_bytes, &self.config).await;
             return Ok(());
         }
         
-        // Read rest of handshake
         let mut handshake = [0u8; HANDSHAKE_LEN];
         handshake[..5].copy_from_slice(&first_bytes);
         self.stream.read_exact(&mut handshake[5..]).await?;
         
-        // Extract fields
         let config = self.config.clone();
         let replay_checker = self.replay_checker.clone();
         let stats = self.stats.clone();
         let buffer_pool = self.buffer_pool.clone();
         
-        // Split stream
         let (read_half, write_half) = self.stream.into_split();
         
-        // Handle MTProto handshake
         let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
-            &handshake,
-            read_half,
-            write_half,
-            peer,
-            &config,
-            &replay_checker,
-            false,
+            &handshake, read_half, write_half, peer,
+            &config, &replay_checker, false,
         ).await {
             HandshakeResult::Success(result) => result,
             HandshakeResult::BadClient { reader, writer } => {
@@ -266,17 +208,12 @@ impl RunningClientHandler {
         };
         
         Self::handle_authenticated_static(
-            crypto_reader, 
-            crypto_writer, 
-            success, 
-            self.upstream_manager, 
-            self.stats, 
-            self.config,
-            buffer_pool
+            crypto_reader, crypto_writer, success,
+            self.upstream_manager, self.stats, self.config,
+            buffer_pool, self.rng,
         ).await
     }
     
-    /// Static version of handle_authenticated_inner
     async fn handle_authenticated_static<R, W>(
         client_reader: CryptoReader<R>,
         client_writer: CryptoWriter<W>,
@@ -285,6 +222,7 @@ impl RunningClientHandler {
         stats: Arc<Stats>,
         config: Arc<ProxyConfig>,
         buffer_pool: Arc<BufferPool>,
+        rng: Arc<SecureRandom>,
     ) -> Result<()>
     where
         R: AsyncRead + Unpin + Send + 'static,
@@ -292,13 +230,11 @@ impl RunningClientHandler {
     {
         let user = &success.user;
         
-        // Check user limits
         if let Err(e) = Self::check_user_limits_static(user, &config, &stats) {
             warn!(user = %user, error = %e, "User limit exceeded");
             return Err(e);
         }
         
-        // Get datacenter address
         let dc_addr = Self::get_dc_addr_static(success.dc_idx, &config)?;
         
         info!(
@@ -307,71 +243,54 @@ impl RunningClientHandler {
             dc = success.dc_idx,
             dc_addr = %dc_addr,
             proto = ?success.proto_tag,
-            fast_mode = config.general.fast_mode,
             "Connecting to Telegram"
         );
         
-        // Connect to Telegram via UpstreamManager
-        let tg_stream = upstream_manager.connect(dc_addr).await?;
+        // Pass dc_idx for latency-based upstream selection
+        let tg_stream = upstream_manager.connect(dc_addr, Some(success.dc_idx)).await?;
         
-        debug!(peer = %success.peer, dc_addr = %dc_addr, "Connected to Telegram, performing handshake");
+        debug!(peer = %success.peer, dc_addr = %dc_addr, "Connected, performing TG handshake");
         
-        // Perform Telegram handshake and get crypto streams
         let (tg_reader, tg_writer) = Self::do_tg_handshake_static(
-            tg_stream, 
-            &success,
-            &config,
+            tg_stream, &success, &config, rng.as_ref(),
         ).await?;
         
-        debug!(peer = %success.peer, "Telegram handshake complete, starting relay");
+        debug!(peer = %success.peer, "TG handshake complete, starting relay");
         
-        // Update stats
         stats.increment_user_connects(user);
         stats.increment_user_curr_connects(user);
         
-        // Relay traffic using buffer pool
         let relay_result = relay_bidirectional(
-            client_reader,
-            client_writer,
-            tg_reader,
-            tg_writer,
-            user,
-            Arc::clone(&stats),
-            buffer_pool,
+            client_reader, client_writer,
+            tg_reader, tg_writer,
+            user, Arc::clone(&stats), buffer_pool,
         ).await;
         
-        // Update stats
         stats.decrement_user_curr_connects(user);
         
         match &relay_result {
-            Ok(()) => debug!(user = %user, peer = %success.peer, "Relay completed normally"),
-            Err(e) => debug!(user = %user, peer = %success.peer, error = %e, "Relay ended with error"),
+            Ok(()) => debug!(user = %user, "Relay completed"),
+            Err(e) => debug!(user = %user, error = %e, "Relay ended with error"),
         }
         
         relay_result
     }
     
-    /// Check user limits (static version)
     fn check_user_limits_static(user: &str, config: &ProxyConfig, stats: &Stats) -> Result<()> {
-        // Check expiration
         if let Some(expiration) = config.access.user_expirations.get(user) {
             if chrono::Utc::now() > *expiration {
                 return Err(ProxyError::UserExpired { user: user.to_string() });
             }
         }
         
-        // Check connection limit
         if let Some(limit) = config.access.user_max_tcp_conns.get(user) {
-            let current = stats.get_user_curr_connects(user);
-            if current >= *limit as u64 {
+            if stats.get_user_curr_connects(user) >= *limit as u64 {
                 return Err(ProxyError::ConnectionLimitExceeded { user: user.to_string() });
             }
         }
         
-        // Check data quota
         if let Some(quota) = config.access.user_data_quota.get(user) {
-            let used = stats.get_user_total_octets(user);
-            if used >= *quota {
+            if stats.get_user_total_octets(user) >= *quota {
                 return Err(ProxyError::DataQuotaExceeded { user: user.to_string() });
             }
         }
@@ -379,62 +298,105 @@ impl RunningClientHandler {
         Ok(())
     }
     
-    /// Get datacenter address by index (static version)
+    /// Resolve DC index to a target address.
+    ///
+    /// Matches the C implementation's behavior exactly:
+    ///
+    /// 1. Look up DC in known clusters (standard DCs ±1..±5)
+    /// 2. If not found and `force=1` → fall back to `default_cluster`
+    ///
+    /// In the C code:
+    /// - `proxy-multi.conf` is downloaded from Telegram, contains only DC ±1..±5
+    /// - `default 2;` directive sets the default cluster
+    /// - `mf_cluster_lookup(CurConf, target_dc, 1)` returns default_cluster
+    ///   for any unknown DC (like CDN DC 203)
+    ///
+    /// So DC 203, DC 101, DC -300, etc. all route to the default DC (2).
+    /// There is NO modular arithmetic in the C implementation.
     fn get_dc_addr_static(dc_idx: i16, config: &ProxyConfig) -> Result<SocketAddr> {
-        let idx = (dc_idx.abs() - 1) as usize;
-        
         let datacenters = if config.general.prefer_ipv6 {
             &*TG_DATACENTERS_V6
         } else {
             &*TG_DATACENTERS_V4
         };
     
-        datacenters.get(idx)
-            .map(|ip| SocketAddr::new(*ip, TG_DATACENTER_PORT))
-            .ok_or_else(|| ProxyError::InvalidHandshake(
-                format!("Invalid DC index: {}", dc_idx)
-            ))
+        let num_dcs = datacenters.len(); // 5
+    
+        // === Step 1: Check dc_overrides (like C's `proxy_for <dc> <ip>:<port>`) ===
+        let dc_key = dc_idx.to_string();
+        if let Some(addr_str) = config.dc_overrides.get(&dc_key) {
+            match addr_str.parse::<SocketAddr>() {
+                Ok(addr) => {
+                    debug!(dc_idx = dc_idx, addr = %addr, "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");
+                }
+            }
+        }
+    
+        // === Step 2: Standard DCs ±1..±5 — direct lookup ===
+        let abs_dc = dc_idx.unsigned_abs() as usize;
+        if abs_dc >= 1 && abs_dc <= num_dcs {
+            return Ok(SocketAddr::new(datacenters[abs_dc - 1], TG_DATACENTER_PORT));
+        }
+    
+        // === Step 3: Unknown DC — fall back to default_cluster ===
+        // Exactly like C's `mf_cluster_lookup(CurConf, target_dc, force=1)`
+        // which returns `MC->default_cluster` when the DC is not found.
+        // Telegram's proxy-multi.conf uses `default 2;`
+        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
+        } else {
+            1 // DC 2 (index 1) — matches Telegram's `default 2;`
+        };
+    
+        info!(
+            original_dc = dc_idx,
+            fallback_dc = (fallback_idx + 1) as u16,
+            fallback_addr = %datacenters[fallback_idx],
+            "Special DC ---> default_cluster"
+        );
+    
+        Ok(SocketAddr::new(datacenters[fallback_idx], TG_DATACENTER_PORT))
     }
     
-    /// Perform handshake with Telegram server (static version)
     async fn do_tg_handshake_static(
         mut stream: TcpStream,
         success: &HandshakeSuccess,
         config: &ProxyConfig,
+        rng: &SecureRandom,
     ) -> Result<(CryptoReader<tokio::net::tcp::OwnedReadHalf>, CryptoWriter<tokio::net::tcp::OwnedWriteHalf>)> {
-        // Generate nonce with keys for TG
         let (nonce, tg_enc_key, tg_enc_iv, tg_dec_key, tg_dec_iv) = generate_tg_nonce(
             success.proto_tag,
-            &success.dec_key,  // Client's dec key
+            &success.dec_key,
             success.dec_iv,
+            rng,
             config.general.fast_mode,
         );
         
-        // Encrypt nonce
         let encrypted_nonce = encrypt_tg_nonce(&nonce);
         
         debug!(
             peer = %success.peer,
             nonce_head = %hex::encode(&nonce[..16]),
-            encrypted_head = %hex::encode(&encrypted_nonce[..16]),
             "Sending nonce to Telegram"
         );
         
-        // Send to Telegram
         stream.write_all(&encrypted_nonce).await?;
         stream.flush().await?;
         
-        debug!(peer = %success.peer, "Nonce sent to Telegram");
-        
-        // Split stream and wrap with crypto
         let (read_half, write_half) = stream.into_split();
         
         let decryptor = AesCtr::new(&tg_dec_key, tg_dec_iv);
         let encryptor = AesCtr::new(&tg_enc_key, tg_enc_iv);
         
-        let tg_reader = CryptoReader::new(read_half, decryptor);
-        let tg_writer = CryptoWriter::new(write_half, encryptor);
-        
-        Ok((tg_reader, tg_writer))
+        Ok((
+            CryptoReader::new(read_half, decryptor),
+            CryptoWriter::new(write_half, encryptor),
+        ))
     }
 }

src/proxy/handshake.rs

@@ -1,11 +1,11 @@
-//! MTProto Handshake Magics
+//! MTProto Handshake
 
 use std::net::SocketAddr;
 use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt};
 use tracing::{debug, warn, trace, info};
+use zeroize::Zeroize;
 
-use crate::crypto::{sha256, AesCtr};
-use crate::crypto::random::SECURE_RANDOM;
+use crate::crypto::{sha256, AesCtr, SecureRandom};
 use crate::protocol::constants::*;
 use crate::protocol::tls;
 use crate::stream::{FakeTlsReader, FakeTlsWriter, CryptoReader, CryptoWriter};
@@ -14,6 +14,9 @@ use crate::stats::ReplayChecker;
 use crate::config::ProxyConfig;
 
 /// Result of successful handshake
+///
+/// Key material (`dec_key`, `dec_iv`, `enc_key`, `enc_iv`) is
+/// zeroized on drop.
 #[derive(Debug, Clone)]
 pub struct HandshakeSuccess {
     /// Authenticated user name
@@ -34,6 +37,15 @@ pub struct HandshakeSuccess {
     pub is_tls: bool,
 }
 
+impl Drop for HandshakeSuccess {
+    fn drop(&mut self) {
+        self.dec_key.zeroize();
+        self.dec_iv.zeroize();
+        self.enc_key.zeroize();
+        self.enc_iv.zeroize();
+    }
+}
+
 /// Handle fake TLS handshake
 pub async fn handle_tls_handshake<R, W>(
     handshake: &[u8],
@@ -42,6 +54,7 @@ pub async fn handle_tls_handshake<R, W>(
     peer: SocketAddr,
     config: &ProxyConfig,
     replay_checker: &ReplayChecker,
+    rng: &SecureRandom,
 ) -> HandshakeResult<(FakeTlsReader<R>, FakeTlsWriter<W>, String), R, W>
 where
     R: AsyncRead + Unpin,
@@ -49,30 +62,25 @@ where
 {
     debug!(peer = %peer, handshake_len = handshake.len(), "Processing TLS handshake");
     
-    // Check minimum length
     if handshake.len() < tls::TLS_DIGEST_POS + tls::TLS_DIGEST_LEN + 1 {
         debug!(peer = %peer, "TLS handshake too short");
         return HandshakeResult::BadClient { reader, writer };
     }
     
-    // Extract digest for replay check
     let digest = &handshake[tls::TLS_DIGEST_POS..tls::TLS_DIGEST_POS + tls::TLS_DIGEST_LEN];
     let digest_half = &digest[..tls::TLS_DIGEST_HALF_LEN];
     
-    // Check for replay
     if replay_checker.check_tls_digest(digest_half) {
         warn!(peer = %peer, "TLS replay attack detected (duplicate digest)");
         return HandshakeResult::BadClient { reader, writer };
     }
     
-    // Build secrets list
     let secrets: Vec<(String, Vec<u8>)> = config.access.users.iter()
         .filter_map(|(name, hex)| {
             hex::decode(hex).ok().map(|bytes| (name.clone(), bytes))
         })
         .collect();
     
-    // Validate handshake
     let validation = match tls::validate_tls_handshake(
         handshake,
         &secrets,
@@ -89,18 +97,17 @@ where
         }
     };
     
-    // Get secret for response
     let secret = match secrets.iter().find(|(name, _)| *name == validation.user) {
         Some((_, s)) => s,
         None => return HandshakeResult::BadClient { reader, writer },
     };
     
-    // Build and send response
     let response = tls::build_server_hello(
         secret,
         &validation.digest,
         &validation.session_id,
         config.censorship.fake_cert_len,
+        rng,
     );
     
     debug!(peer = %peer, response_len = response.len(), "Sending TLS ServerHello");
@@ -115,7 +122,6 @@ where
         return HandshakeResult::Error(ProxyError::Io(e));
     }
     
-    // Record for replay protection only after successful handshake
     replay_checker.add_tls_digest(digest_half);
     
     info!(
@@ -147,26 +153,21 @@ where
 {
     trace!(peer = %peer, handshake = ?hex::encode(handshake), "MTProto handshake bytes");
     
-    // Extract prekey and IV
     let dec_prekey_iv = &handshake[SKIP_LEN..SKIP_LEN + PREKEY_LEN + IV_LEN];
     
-    // Check for replay
     if replay_checker.check_handshake(dec_prekey_iv) {
         warn!(peer = %peer, "MTProto replay attack detected");
         return HandshakeResult::BadClient { reader, writer };
     }
     
-    // Reversed for encryption direction
     let enc_prekey_iv: Vec<u8> = dec_prekey_iv.iter().rev().copied().collect();
     
-    // Try each user's secret
     for (user, secret_hex) in &config.access.users {
         let secret = match hex::decode(secret_hex) {
             Ok(s) => s,
             Err(_) => continue,
         };
         
-        // Derive decryption key
         let dec_prekey = &dec_prekey_iv[..PREKEY_LEN];
         let dec_iv_bytes = &dec_prekey_iv[PREKEY_LEN..];
         
@@ -177,11 +178,9 @@ where
         
         let dec_iv = u128::from_be_bytes(dec_iv_bytes.try_into().unwrap());
         
-        // Decrypt handshake to check protocol tag
         let mut decryptor = AesCtr::new(&dec_key, dec_iv);
         let decrypted = decryptor.decrypt(handshake);
         
-        // Check protocol tag
         let tag_bytes: [u8; 4] = decrypted[PROTO_TAG_POS..PROTO_TAG_POS + 4]
             .try_into()
             .unwrap();
@@ -191,7 +190,6 @@ where
             None => continue,
         };
         
-        // Check if mode is enabled
         let mode_ok = match proto_tag {
             ProtoTag::Secure => {
                 if is_tls { config.general.modes.tls } else { config.general.modes.secure }
@@ -204,12 +202,10 @@ where
             continue;
         }
         
-        // Extract DC index
         let dc_idx = i16::from_le_bytes(
             decrypted[DC_IDX_POS..DC_IDX_POS + 2].try_into().unwrap()
         );
         
-        // Derive encryption key
         let enc_prekey = &enc_prekey_iv[..PREKEY_LEN];
         let enc_iv_bytes = &enc_prekey_iv[PREKEY_LEN..];
         
@@ -220,10 +216,8 @@ where
         
         let enc_iv = u128::from_be_bytes(enc_iv_bytes.try_into().unwrap());
         
-        // Record for replay protection
         replay_checker.add_handshake(dec_prekey_iv);
         
-        // Create new cipher instances
         let decryptor = AesCtr::new(&dec_key, dec_iv);
         let encryptor = AesCtr::new(&enc_key, enc_iv);
         
@@ -264,10 +258,11 @@ pub fn generate_tg_nonce(
     proto_tag: ProtoTag, 
     client_dec_key: &[u8; 32],
     client_dec_iv: u128,
+    rng: &SecureRandom,
     fast_mode: bool,
 ) -> ([u8; HANDSHAKE_LEN], [u8; 32], u128, [u8; 32], u128) {
     loop {
-        let bytes = SECURE_RANDOM.bytes(HANDSHAKE_LEN);
+        let bytes = rng.bytes(HANDSHAKE_LEN);
         let mut nonce: [u8; HANDSHAKE_LEN] = bytes.try_into().unwrap();
         
         if RESERVED_NONCE_FIRST_BYTES.contains(&nonce[0]) { continue; }
@@ -323,13 +318,12 @@ mod tests {
         let client_dec_key = [0x42u8; 32];
         let client_dec_iv = 12345u128;
         
-        let (nonce, tg_enc_key, tg_enc_iv, tg_dec_key, tg_dec_iv) = 
-            generate_tg_nonce(ProtoTag::Secure, &client_dec_key, client_dec_iv, false);
+        let rng = SecureRandom::new();
+        let (nonce, _tg_enc_key, _tg_enc_iv, _tg_dec_key, _tg_dec_iv) = 
+            generate_tg_nonce(ProtoTag::Secure, &client_dec_key, client_dec_iv, &rng, false);
         
-        // Check length
         assert_eq!(nonce.len(), HANDSHAKE_LEN);
         
-        // Check proto tag is set
         let tag_bytes: [u8; 4] = nonce[PROTO_TAG_POS..PROTO_TAG_POS + 4].try_into().unwrap();
         assert_eq!(ProtoTag::from_bytes(tag_bytes), Some(ProtoTag::Secure));
     }
@@ -339,17 +333,35 @@ mod tests {
         let client_dec_key = [0x42u8; 32];
         let client_dec_iv = 12345u128;
         
+        let rng = SecureRandom::new();
         let (nonce, _, _, _, _) = 
-            generate_tg_nonce(ProtoTag::Secure, &client_dec_key, client_dec_iv, false);
+            generate_tg_nonce(ProtoTag::Secure, &client_dec_key, client_dec_iv, &rng, false);
         
         let encrypted = encrypt_tg_nonce(&nonce);
         
         assert_eq!(encrypted.len(), HANDSHAKE_LEN);
-        
-        // First PROTO_TAG_POS bytes should be unchanged
         assert_eq!(&encrypted[..PROTO_TAG_POS], &nonce[..PROTO_TAG_POS]);
-        
-        // Rest should be different (encrypted)
         assert_ne!(&encrypted[PROTO_TAG_POS..], &nonce[PROTO_TAG_POS..]);
     }
+    
+    #[test]
+    fn test_handshake_success_zeroize_on_drop() {
+        let success = HandshakeSuccess {
+            user: "test".to_string(),
+            dc_idx: 2,
+            proto_tag: ProtoTag::Secure,
+            dec_key: [0xAA; 32],
+            dec_iv: 0xBBBBBBBB,
+            enc_key: [0xCC; 32],
+            enc_iv: 0xDDDDDDDD,
+            peer: "127.0.0.1:1234".parse().unwrap(),
+            is_tls: true,
+        };
+        
+        assert_eq!(success.dec_key, [0xAA; 32]);
+        assert_eq!(success.enc_key, [0xCC; 32]);
+        
+        drop(success);
+        // Drop impl zeroizes key material without panic
+    }
 }

src/proxy/masking.rs

@@ -9,6 +9,9 @@ use tracing::debug;
 use crate::config::ProxyConfig;
 
 const MASK_TIMEOUT: Duration = Duration::from_secs(5);
+    /// Maximum duration for the entire masking relay.
+    /// Limits resource consumption from slow-loris attacks and port scanners.
+    const MASK_RELAY_TIMEOUT: Duration = Duration::from_secs(60);
 const MASK_BUFFER_SIZE: usize = 8192;
 
 /// Detect client type based on initial data

src/proxy/relay.rs

@@ -1,20 +1,31 @@
 //! Bidirectional Relay
     
-use std::sync::Arc;
-use std::time::Duration;
-use tokio::io::{AsyncRead, AsyncWrite, AsyncReadExt, AsyncWriteExt};
-use tokio::time::Instant;
-use tracing::{debug, trace, warn, info};
-use crate::error::Result;
-use crate::stats::Stats;
-use crate::stream::BufferPool;
-use std::sync::atomic::{AtomicU64, Ordering};
+    use std::sync::Arc;
+    use std::time::Duration;
+    use tokio::io::{AsyncRead, AsyncWrite, AsyncReadExt, AsyncWriteExt};
+    use tokio::time::Instant;
+    use tracing::{debug, trace, warn};
+    use crate::error::Result;
+    use crate::stats::Stats;
+    use crate::stream::BufferPool;
     
-// Activity timeout for iOS compatibility (30 minutes)
-const ACTIVITY_TIMEOUT_SECS: u64 = 1800;
+    // Activity timeout for iOS compatibility (30 minutes)
+    const ACTIVITY_TIMEOUT_SECS: u64 = 1800;
     
-/// Relay data bidirectionally between client and server
-pub async fn relay_bidirectional<CR, CW, SR, SW>(
+    /// Relay data bidirectionally between client and server.
+    ///
+    /// Uses a single-task select!-based loop instead of spawning two tasks.
+    /// This eliminates:
+    /// - 2× task spawn overhead per connection
+    /// - Zombie task problem (old code used select! on JoinHandles but
+    ///   never aborted the losing task — it would run for up to 30 min)
+    /// - Extra Arc<AtomicU64> allocations for cross-task byte counters
+    ///
+    /// The flush()-per-write was also removed: TCP_NODELAY is set on all
+    /// sockets (socket.rs), so data is pushed immediately without Nagle
+    /// buffering. Explicit flush() on every small read was causing a
+    /// syscall storm and defeating CryptoWriter's internal coalescing.
+    pub async fn relay_bidirectional<CR, CW, SR, SW>(
         mut client_reader: CR,
         mut client_writer: CW,
         mut server_reader: SR,
@@ -22,241 +33,163 @@ pub async fn relay_bidirectional<CR, CW, SR, SW>(
         user: &str,
         stats: Arc<Stats>,
         buffer_pool: Arc<BufferPool>,
-) -> Result<()>
-where
+    ) -> Result<()>
+    where
         CR: AsyncRead + Unpin + Send + 'static,
         CW: AsyncWrite + Unpin + Send + 'static,
         SR: AsyncRead + Unpin + Send + 'static,
         SW: AsyncWrite + Unpin + Send + 'static,
-{
-    let user_c2s = user.to_string();
-    let user_s2c = user.to_string();
+    {
+        // Get buffers from pool — one per direction
+        let mut c2s_buf = buffer_pool.get();
+        let cap = c2s_buf.capacity();
+        c2s_buf.resize(cap, 0);
     
-    let stats_c2s = Arc::clone(&stats);
-    let stats_s2c = Arc::clone(&stats);
-    
-    let c2s_bytes = Arc::new(AtomicU64::new(0));
-    let s2c_bytes = Arc::new(AtomicU64::new(0));
-    let c2s_bytes_clone = Arc::clone(&c2s_bytes);
-    let s2c_bytes_clone = Arc::clone(&s2c_bytes);
+        let mut s2c_buf = buffer_pool.get();
+        let cap = s2c_buf.capacity();
+        s2c_buf.resize(cap, 0);
     
         let activity_timeout = Duration::from_secs(ACTIVITY_TIMEOUT_SECS);
     
-    let pool_c2s = buffer_pool.clone();
-    let pool_s2c = buffer_pool.clone();
+        let mut c2s_total: u64 = 0;
+        let mut s2c_total: u64 = 0;
+        let mut c2s_msgs: u64 = 0;
+        let mut s2c_msgs: u64 = 0;
     
-    // Client -> Server task
-    let c2s = tokio::spawn(async move {
-        // Get buffer from pool
-        let mut pooled_buf = pool_c2s.get();
-        // CRITICAL FIX: BytesMut from pool has len 0. We must resize it to be usable as &mut [u8].
-        // We use the full capacity.
-        let cap = pooled_buf.capacity();
-        pooled_buf.resize(cap, 0);
-        
-        let mut total_bytes = 0u64;
-        let mut prev_total_bytes = 0u64;
-        let mut msg_count = 0u64;
-        let mut last_activity = Instant::now();
+        // For periodic rate logging
+        let mut c2s_prev: u64 = 0;
+        let mut s2c_prev: u64 = 0;
         let mut last_log = Instant::now();
     
-        loop {
-            // Read with timeout
-            let read_result = tokio::time::timeout(
-                activity_timeout,
-                client_reader.read(&mut pooled_buf)
-            ).await;
-            
-            match read_result {
-                Err(_) => {
-                    warn!(
-                        user = %user_c2s,
-                        total_bytes = total_bytes,
-                        msgs = msg_count,
-                        idle_secs = last_activity.elapsed().as_secs(),
-                        "Activity timeout (C->S) - no data received"
-                    );
-                    let _ = server_writer.shutdown().await;
-                    break;
-                }
-                
-                Ok(Ok(0)) => {
-                    debug!(
-                        user = %user_c2s, 
-                        total_bytes = total_bytes,
-                        msgs = msg_count,
-                        "Client closed connection (C->S)"
-                    );
-                    let _ = server_writer.shutdown().await;
-                    break;
-                }
-                
-                Ok(Ok(n)) => {
-                    total_bytes += n as u64;
-                    msg_count += 1;
-                    last_activity = Instant::now();
-                    c2s_bytes_clone.store(total_bytes, Ordering::Relaxed);
-                    
-                    stats_c2s.add_user_octets_from(&user_c2s, n as u64);
-                    stats_c2s.increment_user_msgs_from(&user_c2s);
-                    
-                    trace!(
-                        user = %user_c2s,
-                        bytes = n,
-                        total = total_bytes,
-                        "C->S data"
-                    );
-                    
-                    // Log activity every 10 seconds with correct rate
-                    let elapsed = last_log.elapsed();
-                    if elapsed > Duration::from_secs(10) {
-                        let delta = total_bytes - prev_total_bytes;
-                        let rate = delta as f64 / elapsed.as_secs_f64();
-                        
-                        debug!(
-                            user = %user_c2s,
-                            total_bytes = total_bytes,
-                            msgs = msg_count,
-                            rate_kbps = (rate / 1024.0) as u64,
-                            "C->S transfer in progress"
-                        );
-                        
-                        last_log = Instant::now();
-                        prev_total_bytes = total_bytes;
-                    }
-                    
-                    if let Err(e) = server_writer.write_all(&pooled_buf[..n]).await {
-                        debug!(user = %user_c2s, error = %e, "Failed to write to server");
-                        break;
-                    }
-                    if let Err(e) = server_writer.flush().await {
-                        debug!(user = %user_c2s, error = %e, "Failed to flush to server");
-                        break;
-                    }
-                }
-                
-                Ok(Err(e)) => {
-                    debug!(user = %user_c2s, error = %e, total_bytes = total_bytes, "Client read error");
-                    break;
-                }
-            }
-        }
-    });
-    
-    // Server -> Client task
-    let s2c = tokio::spawn(async move {
-        // Get buffer from pool
-        let mut pooled_buf = pool_s2c.get();
-        // CRITICAL FIX: Resize buffer
-        let cap = pooled_buf.capacity();
-        pooled_buf.resize(cap, 0);
-
-        let mut total_bytes = 0u64;
-        let mut prev_total_bytes = 0u64;
-        let mut msg_count = 0u64;
-        let mut last_activity = Instant::now();
-        let mut last_log = Instant::now();
+        let user_owned = user.to_string();
     
         loop {
-            let read_result = tokio::time::timeout(
-                activity_timeout,
-                server_reader.read(&mut pooled_buf)
-            ).await;
-            
-            match read_result {
-                Err(_) => {
-                    warn!(
-                        user = %user_s2c,
-                        total_bytes = total_bytes,
-                        msgs = msg_count,
-                        idle_secs = last_activity.elapsed().as_secs(),
-                        "Activity timeout (S->C) - no data received"
-                    );
-                    let _ = client_writer.shutdown().await;
-                    break;
-                }
-                
-                Ok(Ok(0)) => {
-                    debug!(
-                        user = %user_s2c,
-                        total_bytes = total_bytes,
-                        msgs = msg_count,
-                        "Server closed connection (S->C)"
-                    );
-                    let _ = client_writer.shutdown().await;
-                    break;
-                }
-                
-                Ok(Ok(n)) => {
-                    total_bytes += n as u64;
-                    msg_count += 1;
-                    last_activity = Instant::now();
-                    s2c_bytes_clone.store(total_bytes, Ordering::Relaxed);
-                    
-                    stats_s2c.add_user_octets_to(&user_s2c, n as u64);
-                    stats_s2c.increment_user_msgs_to(&user_s2c);
-                    
-                    trace!(
-                        user = %user_s2c,
-                        bytes = n,
-                        total = total_bytes,
-                        "S->C data"
-                    );
-                    
-                    let elapsed = last_log.elapsed();
-                    if elapsed > Duration::from_secs(10) {
-                        let delta = total_bytes - prev_total_bytes;
-                        let rate = delta as f64 / elapsed.as_secs_f64();
-                        
-                        debug!(
-                            user = %user_s2c,
-                            total_bytes = total_bytes,
-                            msgs = msg_count,
-                            rate_kbps = (rate / 1024.0) as u64,
-                            "S->C transfer in progress"
-                        );
-                        
-                        last_log = Instant::now();
-                        prev_total_bytes = total_bytes;
-                    }
-                    
-                    if let Err(e) = client_writer.write_all(&pooled_buf[..n]).await {
-                        debug!(user = %user_s2c, error = %e, "Failed to write to client");
-                        break;
-                    }
-                    if let Err(e) = client_writer.flush().await {
-                        debug!(user = %user_s2c, error = %e, "Failed to flush to client");
-                        break;
-                    }
-                }
-                
-                Ok(Err(e)) => {
-                    debug!(user = %user_s2c, error = %e, total_bytes = total_bytes, "Server read error");
-                    break;
-                }
-            }
-        }
-    });
-    
-    // Wait for either direction to complete
             tokio::select! {
-        result = c2s => {
-            if let Err(e) = result {
-                warn!(error = %e, "C->S task panicked");
+                biased;
+    
+                // Client -> Server direction
+                result = tokio::time::timeout(activity_timeout, client_reader.read(&mut c2s_buf)) => {
+                    match result {
+                        Err(_) => {
+                            // Activity timeout
+                            warn!(
+                                user = %user_owned,
+                                c2s_bytes = c2s_total,
+                                s2c_bytes = s2c_total,
+                                "Activity timeout (C->S)"
+                            );
+                            break;
+                        }
+                        Ok(Ok(0)) => {
+                            // Client closed
+                            debug!(
+                                user = %user_owned,
+                                c2s_bytes = c2s_total,
+                                s2c_bytes = s2c_total,
+                                "Client closed connection"
+                            );
+                            break;
+                        }
+                        Ok(Ok(n)) => {
+                            c2s_total += n as u64;
+                            c2s_msgs += 1;
+    
+                            stats.add_user_octets_from(&user_owned, n as u64);
+                            stats.increment_user_msgs_from(&user_owned);
+    
+                            trace!(user = %user_owned, bytes = n, "C->S");
+    
+                            // Write without flush — TCP_NODELAY handles push
+                            if let Err(e) = server_writer.write_all(&c2s_buf[..n]).await {
+                                debug!(user = %user_owned, error = %e, "Write to server failed");
+                                break;
                             }
                         }
-        result = s2c => {
-            if let Err(e) = result {
-                warn!(error = %e, "S->C task panicked");
+                        Ok(Err(e)) => {
+                            debug!(user = %user_owned, error = %e, "Client read error");
+                            break;
                         }
                     }
                 }
     
+                // Server -> Client direction
+                result = tokio::time::timeout(activity_timeout, server_reader.read(&mut s2c_buf)) => {
+                    match result {
+                        Err(_) => {
+                            warn!(
+                                user = %user_owned,
+                                c2s_bytes = c2s_total,
+                                s2c_bytes = s2c_total,
+                                "Activity timeout (S->C)"
+                            );
+                            break;
+                        }
+                        Ok(Ok(0)) => {
                             debug!(
-        c2s_bytes = c2s_bytes.load(Ordering::Relaxed),
-        s2c_bytes = s2c_bytes.load(Ordering::Relaxed),
+                                user = %user_owned,
+                                c2s_bytes = c2s_total,
+                                s2c_bytes = s2c_total,
+                                "Server closed connection"
+                            );
+                            break;
+                        }
+                        Ok(Ok(n)) => {
+                            s2c_total += n as u64;
+                            s2c_msgs += 1;
+    
+                            stats.add_user_octets_to(&user_owned, n as u64);
+                            stats.increment_user_msgs_to(&user_owned);
+    
+                            trace!(user = %user_owned, bytes = n, "S->C");
+    
+                            if let Err(e) = client_writer.write_all(&s2c_buf[..n]).await {
+                                debug!(user = %user_owned, error = %e, "Write to client failed");
+                                break;
+                            }
+                        }
+                        Ok(Err(e)) => {
+                            debug!(user = %user_owned, error = %e, "Server read error");
+                            break;
+                        }
+                    }
+                }
+            }
+    
+            // Periodic rate logging (every 10s)
+            let elapsed = last_log.elapsed();
+            if elapsed > Duration::from_secs(10) {
+                let secs = elapsed.as_secs_f64();
+                let c2s_delta = c2s_total - c2s_prev;
+                let s2c_delta = s2c_total - s2c_prev;
+    
+                debug!(
+                    user = %user_owned,
+                    c2s_kbps = (c2s_delta as f64 / secs / 1024.0) as u64,
+                    s2c_kbps = (s2c_delta as f64 / secs / 1024.0) as u64,
+                    c2s_total = c2s_total,
+                    s2c_total = s2c_total,
+                    "Relay active"
+                );
+    
+                c2s_prev = c2s_total;
+                s2c_prev = s2c_total;
+                last_log = Instant::now();
+            }
+        }
+    
+        // Clean shutdown of both directions
+        let _ = server_writer.shutdown().await;
+        let _ = client_writer.shutdown().await;
+    
+        debug!(
+            user = %user_owned,
+            c2s_bytes = c2s_total,
+            s2c_bytes = s2c_total,
+            c2s_msgs = c2s_msgs,
+            s2c_msgs = s2c_msgs,
             "Relay finished"
         );
     
         Ok(())
-}
+    }
+    

src/stats/mod.rs

@@ -1,31 +1,28 @@
-//! Statistics
+//! Statistics and replay protection
 
 use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::Arc;
-use std::time::Instant;
+use std::time::{Instant, Duration};
 use dashmap::DashMap;
-use parking_lot::{RwLock, Mutex};
+use parking_lot::Mutex;
 use lru::LruCache;
 use std::num::NonZeroUsize;
 use std::hash::{Hash, Hasher};
 use std::collections::hash_map::DefaultHasher;
+use std::collections::VecDeque;
+use tracing::debug;
+
+// ============= Stats =============
 
-/// Thread-safe statistics
 #[derive(Default)]
 pub struct Stats {
-    // Global counters
     connects_all: AtomicU64,
     connects_bad: AtomicU64,
     handshake_timeouts: AtomicU64,
-    
-    // Per-user stats
     user_stats: DashMap<String, UserStats>,
-    
-    // Start time
-    start_time: RwLock<Option<Instant>>,
+    start_time: parking_lot::RwLock<Option<Instant>>,
 }
 
-/// Per-user statistics
 #[derive(Default)]
 pub struct UserStats {
     pub connects: AtomicU64,
@@ -43,42 +40,20 @@ impl Stats {
         stats
     }
     
-    // Global stats
-    pub fn increment_connects_all(&self) {
-        self.connects_all.fetch_add(1, Ordering::Relaxed);
-    }
+    pub fn increment_connects_all(&self) { self.connects_all.fetch_add(1, Ordering::Relaxed); }
+    pub fn increment_connects_bad(&self) { self.connects_bad.fetch_add(1, Ordering::Relaxed); }
+    pub fn increment_handshake_timeouts(&self) { self.handshake_timeouts.fetch_add(1, Ordering::Relaxed); }
+    pub fn get_connects_all(&self) -> u64 { self.connects_all.load(Ordering::Relaxed) }
+    pub fn get_connects_bad(&self) -> u64 { self.connects_bad.load(Ordering::Relaxed) }
     
-    pub fn increment_connects_bad(&self) {
-        self.connects_bad.fetch_add(1, Ordering::Relaxed);
-    }
-    
-    pub fn increment_handshake_timeouts(&self) {
-        self.handshake_timeouts.fetch_add(1, Ordering::Relaxed);
-    }
-    
-    pub fn get_connects_all(&self) -> u64 {
-        self.connects_all.load(Ordering::Relaxed)
-    }
-    
-    pub fn get_connects_bad(&self) -> u64 {
-        self.connects_bad.load(Ordering::Relaxed)
-    }
-    
-    // User stats
     pub fn increment_user_connects(&self, user: &str) {
-        self.user_stats
-            .entry(user.to_string())
-            .or_default()
-            .connects
-            .fetch_add(1, Ordering::Relaxed);
+        self.user_stats.entry(user.to_string()).or_default()
+            .connects.fetch_add(1, Ordering::Relaxed);
     }
     
     pub fn increment_user_curr_connects(&self, user: &str) {
-        self.user_stats
-            .entry(user.to_string())
-            .or_default()
-            .curr_connects
-            .fetch_add(1, Ordering::Relaxed);
+        self.user_stats.entry(user.to_string()).or_default()
+            .curr_connects.fetch_add(1, Ordering::Relaxed);
     }
     
     pub fn decrement_user_curr_connects(&self, user: &str) {
@@ -88,47 +63,33 @@ impl Stats {
     }
     
     pub fn get_user_curr_connects(&self, user: &str) -> u64 {
-        self.user_stats
-            .get(user)
+        self.user_stats.get(user)
             .map(|s| s.curr_connects.load(Ordering::Relaxed))
             .unwrap_or(0)
     }
     
     pub fn add_user_octets_from(&self, user: &str, bytes: u64) {
-        self.user_stats
-            .entry(user.to_string())
-            .or_default()
-            .octets_from_client
-            .fetch_add(bytes, Ordering::Relaxed);
+        self.user_stats.entry(user.to_string()).or_default()
+            .octets_from_client.fetch_add(bytes, Ordering::Relaxed);
     }
     
     pub fn add_user_octets_to(&self, user: &str, bytes: u64) {
-        self.user_stats
-            .entry(user.to_string())
-            .or_default()
-            .octets_to_client
-            .fetch_add(bytes, Ordering::Relaxed);
+        self.user_stats.entry(user.to_string()).or_default()
+            .octets_to_client.fetch_add(bytes, Ordering::Relaxed);
     }
     
     pub fn increment_user_msgs_from(&self, user: &str) {
-        self.user_stats
-            .entry(user.to_string())
-            .or_default()
-            .msgs_from_client
-            .fetch_add(1, Ordering::Relaxed);
+        self.user_stats.entry(user.to_string()).or_default()
+            .msgs_from_client.fetch_add(1, Ordering::Relaxed);
     }
     
     pub fn increment_user_msgs_to(&self, user: &str) {
-        self.user_stats
-            .entry(user.to_string())
-            .or_default()
-            .msgs_to_client
-            .fetch_add(1, Ordering::Relaxed);
+        self.user_stats.entry(user.to_string()).or_default()
+            .msgs_to_client.fetch_add(1, Ordering::Relaxed);
     }
     
     pub fn get_user_total_octets(&self, user: &str) -> u64 {
-        self.user_stats
-            .get(user)
+        self.user_stats.get(user)
             .map(|s| {
                 s.octets_from_client.load(Ordering::Relaxed) +
                 s.octets_to_client.load(Ordering::Relaxed)
@@ -143,57 +104,209 @@ impl Stats {
     }
 }
 
-/// Sharded Replay attack checker using LRU cache
-/// Uses multiple independent LRU caches to reduce lock contention
+// ============= Replay Checker =============
+
 pub struct ReplayChecker {
-    shards: Vec<Mutex<LruCache<Vec<u8>, ()>>>,
+    shards: Vec<Mutex<ReplayShard>>,
     shard_mask: usize,
+    window: Duration,
+    checks: AtomicU64,
+    hits: AtomicU64,
+    additions: AtomicU64,
+    cleanups: AtomicU64,
+}
+
+struct ReplayEntry {
+    seen_at: Instant,
+    seq: u64,
+}
+
+struct ReplayShard {
+    cache: LruCache<Box<[u8]>, ReplayEntry>,
+    queue: VecDeque<(Instant, Box<[u8]>, u64)>,
+    seq_counter: u64,
+}
+
+impl ReplayShard {
+    fn new(cap: NonZeroUsize) -> Self {
+        Self {
+            cache: LruCache::new(cap),
+            queue: VecDeque::with_capacity(cap.get()),
+            seq_counter: 0,
+        }
+    }
+    
+    fn next_seq(&mut self) -> u64 {
+        self.seq_counter += 1;
+        self.seq_counter
+    }
+
+    fn cleanup(&mut self, now: Instant, window: Duration) {
+        if window.is_zero() {
+            return;
+        }
+        let cutoff = now.checked_sub(window).unwrap_or(now);
+        
+        while let Some((ts, _, _)) = self.queue.front() {
+            if *ts >= cutoff {
+                break;
+            }
+            let (_, key, queue_seq) = self.queue.pop_front().unwrap();
+            
+            // Use key.as_ref() to get &[u8] — avoids Borrow<Q> ambiguity
+            // between Borrow<[u8]> and Borrow<Box<[u8]>>
+            if let Some(entry) = self.cache.peek(key.as_ref()) {
+                if entry.seq == queue_seq {
+                    self.cache.pop(key.as_ref());
+                }
+            }
+        }
+    }
+    
+    fn check(&mut self, key: &[u8], now: Instant, window: Duration) -> bool {
+        self.cleanup(now, window);
+        // key is &[u8], resolves Q=[u8] via Box<[u8]>: Borrow<[u8]>
+        self.cache.get(key).is_some()
+    }
+    
+    fn add(&mut self, key: &[u8], now: Instant, window: Duration) {
+        self.cleanup(now, window);
+        
+        let seq = self.next_seq();
+        let boxed_key: Box<[u8]> = key.into();
+        
+        self.cache.put(boxed_key.clone(), ReplayEntry { seen_at: now, seq });
+        self.queue.push_back((now, boxed_key, seq));
+    }
+    
+    fn len(&self) -> usize {
+        self.cache.len()
+    }
 }
 
 impl ReplayChecker {
-    /// Create new replay checker with specified capacity per shard
-    /// Total capacity = capacity * num_shards
-    pub fn new(total_capacity: usize) -> Self {
-        // Use 64 shards for good concurrency
+    pub fn new(total_capacity: usize, window: Duration) -> Self {
         let num_shards = 64;
         let shard_capacity = (total_capacity / num_shards).max(1);
         let cap = NonZeroUsize::new(shard_capacity).unwrap();
 
         let mut shards = Vec::with_capacity(num_shards);
         for _ in 0..num_shards {
-            shards.push(Mutex::new(LruCache::new(cap)));
+            shards.push(Mutex::new(ReplayShard::new(cap)));
         }
 
         Self {
             shards,
             shard_mask: num_shards - 1,
+            window,
+            checks: AtomicU64::new(0),
+            hits: AtomicU64::new(0),
+            additions: AtomicU64::new(0),
+            cleanups: AtomicU64::new(0),
         }
     }
 
-    fn get_shard(&self, key: &[u8]) -> usize {
+    fn get_shard_idx(&self, key: &[u8]) -> usize {
         let mut hasher = DefaultHasher::new();
         key.hash(&mut hasher);
         (hasher.finish() as usize) & self.shard_mask
     }
 
-    pub fn check_handshake(&self, data: &[u8]) -> bool {
-        let shard_idx = self.get_shard(data);
-        self.shards[shard_idx].lock().contains(&data.to_vec())
+    fn check(&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);
+        if found {
+            self.hits.fetch_add(1, Ordering::Relaxed);
+        }
+        found
     }
 
-    pub fn add_handshake(&self, data: &[u8]) {
-        let shard_idx = self.get_shard(data);
-        self.shards[shard_idx].lock().put(data.to_vec(), ());
+    fn add(&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_tls_digest(&self, data: &[u8]) -> bool {
-        let shard_idx = self.get_shard(data);
-        self.shards[shard_idx].lock().contains(&data.to_vec())
+    pub fn check_handshake(&self, data: &[u8]) -> bool { self.check(data) }
+    pub fn add_handshake(&self, data: &[u8]) { self.add(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 stats(&self) -> ReplayStats {
+        let mut total_entries = 0;
+        let mut total_queue_len = 0;
+        for shard in &self.shards {
+            let s = shard.lock();
+            total_entries += s.cache.len();
+            total_queue_len += s.queue.len();
         }
         
-    pub fn add_tls_digest(&self, data: &[u8]) {
-        let shard_idx = self.get_shard(data);
-        self.shards[shard_idx].lock().put(data.to_vec(), ());
+        ReplayStats {
+            total_entries,
+            total_queue_len,
+            total_checks: self.checks.load(Ordering::Relaxed),
+            total_hits: self.hits.load(Ordering::Relaxed),
+            total_additions: self.additions.load(Ordering::Relaxed),
+            total_cleanups: self.cleanups.load(Ordering::Relaxed),
+            num_shards: self.shards.len(),
+            window_secs: self.window.as_secs(),
+        }
+    }
+    
+    pub async fn run_periodic_cleanup(&self) {
+        let interval = if self.window.as_secs() > 60 {
+            Duration::from_secs(30)
+        } else {
+            Duration::from_secs(self.window.as_secs().max(1) / 2)
+        };
+        
+        loop {
+            tokio::time::sleep(interval).await;
+            
+            let now = Instant::now();
+            let mut cleaned = 0usize;
+            
+            for shard_mutex in &self.shards {
+                let mut shard = shard_mutex.lock();
+                let before = shard.len();
+                shard.cleanup(now, self.window);
+                let after = shard.len();
+                cleaned += before.saturating_sub(after);
+            }
+            
+            self.cleanups.fetch_add(1, Ordering::Relaxed);
+            
+            if cleaned > 0 {
+                debug!(cleaned = cleaned, "Replay checker: periodic cleanup");
+            }
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct ReplayStats {
+    pub total_entries: usize,
+    pub total_queue_len: usize,
+    pub total_checks: u64,
+    pub total_hits: u64,
+    pub total_additions: u64,
+    pub total_cleanups: u64,
+    pub num_shards: usize,
+    pub window_secs: u64,
+}
+
+impl ReplayStats {
+    pub fn hit_rate(&self) -> f64 {
+        if self.total_checks == 0 { 0.0 }
+        else { (self.total_hits as f64 / self.total_checks as f64) * 100.0 }
+    }
+    
+    pub fn ghost_ratio(&self) -> f64 {
+        if self.total_entries == 0 { 0.0 }
+        else { self.total_queue_len as f64 / self.total_entries as f64 }
     }
 }
 
@@ -204,28 +317,60 @@ mod tests {
     #[test]
     fn test_stats_shared_counters() {
         let stats = Arc::new(Stats::new());
-        
-        let stats1 = Arc::clone(&stats);
-        let stats2 = Arc::clone(&stats);
-        
-        stats1.increment_connects_all();
-        stats2.increment_connects_all();
-        stats1.increment_connects_all();
-        
+        stats.increment_connects_all();
+        stats.increment_connects_all();
+        stats.increment_connects_all();
         assert_eq!(stats.get_connects_all(), 3);
     }
     
     #[test]
-    fn test_replay_checker_sharding() {
-        let checker = ReplayChecker::new(100);
-        let data1 = b"test1";
-        let data2 = b"test2";
+    fn test_replay_checker_basic() {
+        let checker = ReplayChecker::new(100, Duration::from_secs(60));
+        assert!(!checker.check_handshake(b"test1"));
+        checker.add_handshake(b"test1");
+        assert!(checker.check_handshake(b"test1"));
+        assert!(!checker.check_handshake(b"test2"));
+    }
     
-        checker.add_handshake(data1);
-        assert!(checker.check_handshake(data1));
-        assert!(!checker.check_handshake(data2));
+    #[test]
+    fn test_replay_checker_duplicate_add() {
+        let checker = ReplayChecker::new(100, Duration::from_secs(60));
+        checker.add_handshake(b"dup");
+        checker.add_handshake(b"dup");
+        assert!(checker.check_handshake(b"dup"));
+    }
     
-        checker.add_handshake(data2);
-        assert!(checker.check_handshake(data2));
+    #[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"));
+        std::thread::sleep(Duration::from_millis(100));
+        assert!(!checker.check_handshake(b"expire"));
+    }
+    
+    #[test]
+    fn test_replay_checker_stats() {
+        let checker = ReplayChecker::new(100, Duration::from_secs(60));
+        checker.add_handshake(b"k1");
+        checker.add_handshake(b"k2");
+        checker.check_handshake(b"k1");
+        checker.check_handshake(b"k3");
+        let stats = checker.stats();
+        assert_eq!(stats.total_additions, 2);
+        assert_eq!(stats.total_checks, 2);
+        assert_eq!(stats.total_hits, 1);
+    }
+    
+    #[test]
+    fn test_replay_checker_many_keys() {
+        let checker = ReplayChecker::new(1000, Duration::from_secs(60));
+        for i in 0..500u32 {
+            checker.add(&i.to_le_bytes());
+        }
+        for i in 0..500u32 {
+            assert!(checker.check(&i.to_le_bytes()));
+        }
+        assert_eq!(checker.stats().total_entries, 500);
     }
 }

src/stream/frame.rs

@@ -5,8 +5,10 @@
 
 use bytes::{Bytes, BytesMut};
 use std::io::Result;
+use std::sync::Arc;
 
 use crate::protocol::constants::ProtoTag;
+use crate::crypto::SecureRandom;
 
 // ============= Frame Types =============
 
@@ -147,11 +149,11 @@ pub trait FrameCodec: Send + Sync {
 // ============= Codec Factory =============
 
 /// Create a frame codec for the given protocol tag
-pub fn create_codec(proto_tag: ProtoTag) -> Box<dyn FrameCodec> {
+pub fn create_codec(proto_tag: ProtoTag, rng: Arc<SecureRandom>) -> Box<dyn FrameCodec> {
     match proto_tag {
         ProtoTag::Abridged => Box::new(crate::stream::frame_codec::AbridgedCodec::new()),
         ProtoTag::Intermediate => Box::new(crate::stream::frame_codec::IntermediateCodec::new()),
-        ProtoTag::Secure => Box::new(crate::stream::frame_codec::SecureCodec::new()),
+        ProtoTag::Secure => Box::new(crate::stream::frame_codec::SecureCodec::new(rng)),
     }
 }
 

src/stream/frame_codec.rs

@@ -5,9 +5,11 @@
 
 use bytes::{Bytes, BytesMut, BufMut};
 use std::io::{self, Error, ErrorKind};
+use std::sync::Arc;
 use tokio_util::codec::{Decoder, Encoder};
 
 use crate::protocol::constants::ProtoTag;
+use crate::crypto::SecureRandom;
 use super::frame::{Frame, FrameMeta, FrameCodec as FrameCodecTrait};
 
 // ============= Unified Codec =============
@@ -21,14 +23,17 @@ pub struct FrameCodec {
     proto_tag: ProtoTag,
     /// Maximum allowed frame size
     max_frame_size: usize,
+    /// RNG for secure padding
+    rng: Arc<SecureRandom>,
 }
 
 impl FrameCodec {
     /// Create a new codec for the given protocol
-    pub fn new(proto_tag: ProtoTag) -> Self {
+    pub fn new(proto_tag: ProtoTag, rng: Arc<SecureRandom>) -> Self {
         Self {
             proto_tag,
             max_frame_size: 16 * 1024 * 1024, // 16MB default
+            rng,
         }
     }
     
@@ -64,7 +69,7 @@ impl Encoder<Frame> for FrameCodec {
         match self.proto_tag {
             ProtoTag::Abridged => encode_abridged(&frame, dst),
             ProtoTag::Intermediate => encode_intermediate(&frame, dst),
-            ProtoTag::Secure => encode_secure(&frame, dst),
+            ProtoTag::Secure => encode_secure(&frame, dst, &self.rng),
         }
     }
 }
@@ -288,9 +293,7 @@ fn decode_secure(src: &mut BytesMut, max_size: usize) -> io::Result<Option<Frame
     Ok(Some(Frame::with_meta(data, meta)))
 }
 
-fn encode_secure(frame: &Frame, dst: &mut BytesMut) -> io::Result<()> {
-    use crate::crypto::random::SECURE_RANDOM;
-    
+fn encode_secure(frame: &Frame, dst: &mut BytesMut, rng: &SecureRandom) -> io::Result<()> {
     let data = &frame.data;
     
     // Simple ACK: just send data
@@ -303,10 +306,10 @@ fn encode_secure(frame: &Frame, dst: &mut BytesMut) -> io::Result<()> {
     // Generate padding to make length not divisible by 4
     let padding_len = if data.len() % 4 == 0 {
         // Add 1-3 bytes to make it non-aligned
-        (SECURE_RANDOM.range(3) + 1) as usize
+        (rng.range(3) + 1) as usize
     } else {
         // Already non-aligned, can add 0-3
-        SECURE_RANDOM.range(4) as usize
+        rng.range(4) as usize
     };
     
     let total_len = data.len() + padding_len;
@@ -321,7 +324,7 @@ fn encode_secure(frame: &Frame, dst: &mut BytesMut) -> io::Result<()> {
     dst.extend_from_slice(data);
     
     if padding_len > 0 {
-        let padding = SECURE_RANDOM.bytes(padding_len);
+        let padding = rng.bytes(padding_len);
         dst.extend_from_slice(&padding);
     }
     
@@ -445,19 +448,21 @@ impl FrameCodecTrait for IntermediateCodec {
 /// Secure Intermediate protocol codec
 pub struct SecureCodec {
     max_frame_size: usize,
+    rng: Arc<SecureRandom>,
 }
 
 impl SecureCodec {
-    pub fn new() -> Self {
+    pub fn new(rng: Arc<SecureRandom>) -> Self {
         Self {
             max_frame_size: 16 * 1024 * 1024,
+            rng,
         }
     }
 }
 
 impl Default for SecureCodec {
     fn default() -> Self {
-        Self::new()
+        Self::new(Arc::new(SecureRandom::new()))
     }
 }
 
@@ -474,7 +479,7 @@ impl Encoder<Frame> for SecureCodec {
     type Error = io::Error;
     
     fn encode(&mut self, frame: Frame, dst: &mut BytesMut) -> Result<(), Self::Error> {
-        encode_secure(&frame, dst)
+        encode_secure(&frame, dst, &self.rng)
     }
 }
 
@@ -485,7 +490,7 @@ impl FrameCodecTrait for SecureCodec {
     
     fn encode(&self, frame: &Frame, dst: &mut BytesMut) -> io::Result<usize> {
         let before = dst.len();
-        encode_secure(frame, dst)?;
+        encode_secure(frame, dst, &self.rng)?;
         Ok(dst.len() - before)
     }
     
@@ -506,6 +511,8 @@ mod tests {
     use tokio_util::codec::{FramedRead, FramedWrite};
     use tokio::io::duplex;
     use futures::{SinkExt, StreamExt};
+    use crate::crypto::SecureRandom;
+    use std::sync::Arc;
     
     #[tokio::test]
     async fn test_framed_abridged() {
@@ -541,8 +548,8 @@ mod tests {
     async fn test_framed_secure() {
         let (client, server) = duplex(4096);
         
-        let mut writer = FramedWrite::new(client, SecureCodec::new());
-        let mut reader = FramedRead::new(server, SecureCodec::new());
+        let mut writer = FramedWrite::new(client, SecureCodec::new(Arc::new(SecureRandom::new())));
+        let mut reader = FramedRead::new(server, SecureCodec::new(Arc::new(SecureRandom::new())));
         
         let original = Bytes::from_static(&[1, 2, 3, 4, 5, 6, 7, 8]);
         let frame = Frame::new(original.clone());
@@ -557,8 +564,8 @@ mod tests {
         for proto_tag in [ProtoTag::Abridged, ProtoTag::Intermediate, ProtoTag::Secure] {
             let (client, server) = duplex(4096);
             
-            let mut writer = FramedWrite::new(client, FrameCodec::new(proto_tag));
-            let mut reader = FramedRead::new(server, FrameCodec::new(proto_tag));
+            let mut writer = FramedWrite::new(client, FrameCodec::new(proto_tag, Arc::new(SecureRandom::new())));
+            let mut reader = FramedRead::new(server, FrameCodec::new(proto_tag, Arc::new(SecureRandom::new())));
             
             // Use 4-byte aligned data for abridged compatibility
             let original = Bytes::from_static(&[1, 2, 3, 4, 5, 6, 7, 8]);
@@ -607,7 +614,7 @@ mod tests {
     
     #[test]
     fn test_frame_too_large() {
-        let mut codec = FrameCodec::new(ProtoTag::Intermediate)
+        let mut codec = FrameCodec::new(ProtoTag::Intermediate, Arc::new(SecureRandom::new()))
             .with_max_frame_size(100);
         
         // Create a "frame" that claims to be very large

src/stream/frame_stream.rs

@@ -4,8 +4,8 @@ use bytes::{Bytes, BytesMut};
 use std::io::{Error, ErrorKind, Result};
 use tokio::io::{AsyncRead, AsyncWrite, AsyncReadExt, AsyncWriteExt};
 use crate::protocol::constants::*;
-use crate::crypto::crc32;
-use crate::crypto::random::SECURE_RANDOM;
+use crate::crypto::{crc32, SecureRandom};
+use std::sync::Arc;
 use super::traits::{FrameMeta, LayeredStream};
 
 // ============= Abridged (Compact) Frame =============
@@ -251,11 +251,12 @@ impl<R> LayeredStream<R> for SecureIntermediateFrameReader<R> {
 /// Writer for secure intermediate MTProto framing
 pub struct SecureIntermediateFrameWriter<W> {
     upstream: W,
+    rng: Arc<SecureRandom>,
 }
 
 impl<W> SecureIntermediateFrameWriter<W> {
-    pub fn new(upstream: W) -> Self {
-        Self { upstream }
+    pub fn new(upstream: W, rng: Arc<SecureRandom>) -> Self {
+        Self { upstream, rng }
     }
 }
 
@@ -267,8 +268,8 @@ impl<W: AsyncWrite + Unpin> SecureIntermediateFrameWriter<W> {
         }
         
         // Add random padding (0-3 bytes)
-        let padding_len = SECURE_RANDOM.range(4);
-        let padding = SECURE_RANDOM.bytes(padding_len);
+        let padding_len = self.rng.range(4);
+        let padding = self.rng.bytes(padding_len);
         
         let total_len = data.len() + padding_len;
         let len_bytes = (total_len as u32).to_le_bytes();
@@ -454,11 +455,11 @@ pub enum FrameWriterKind<W> {
 }
 
 impl<W: AsyncWrite + Unpin> FrameWriterKind<W> {
-    pub fn new(upstream: W, proto_tag: ProtoTag) -> Self {
+    pub fn new(upstream: W, proto_tag: ProtoTag, rng: Arc<SecureRandom>) -> Self {
         match proto_tag {
             ProtoTag::Abridged => FrameWriterKind::Abridged(AbridgedFrameWriter::new(upstream)),
             ProtoTag::Intermediate => FrameWriterKind::Intermediate(IntermediateFrameWriter::new(upstream)),
-            ProtoTag::Secure => FrameWriterKind::SecureIntermediate(SecureIntermediateFrameWriter::new(upstream)),
+            ProtoTag::Secure => FrameWriterKind::SecureIntermediate(SecureIntermediateFrameWriter::new(upstream, rng)),
         }
     }
     
@@ -483,6 +484,8 @@ impl<W: AsyncWrite + Unpin> FrameWriterKind<W> {
 mod tests {
     use super::*;
     use tokio::io::duplex;
+    use std::sync::Arc;
+    use crate::crypto::SecureRandom;
     
     #[tokio::test]
     async fn test_abridged_roundtrip() {
@@ -539,7 +542,7 @@ mod tests {
     async fn test_secure_intermediate_padding() {
         let (client, server) = duplex(1024);
         
-        let mut writer = SecureIntermediateFrameWriter::new(client);
+        let mut writer = SecureIntermediateFrameWriter::new(client, Arc::new(SecureRandom::new()));
         let mut reader = SecureIntermediateFrameReader::new(server);
         
         let data = vec![1u8, 2, 3, 4, 5, 6, 7, 8];
@@ -572,7 +575,7 @@ mod tests {
     async fn test_frame_reader_kind() {
         let (client, server) = duplex(1024);
         
-        let mut writer = FrameWriterKind::new(client, ProtoTag::Intermediate);
+        let mut writer = FrameWriterKind::new(client, ProtoTag::Intermediate, Arc::new(SecureRandom::new()));
         let mut reader = FrameReaderKind::new(server, ProtoTag::Intermediate);
         
         let data = vec![1u8, 2, 3, 4];

src/transport/mod.rs

@@ -10,4 +10,4 @@ pub use pool::ConnectionPool;
 pub use proxy_protocol::{ProxyProtocolInfo, parse_proxy_protocol};
 pub use socket::*;
 pub use socks::*;
-pub use upstream::UpstreamManager;
+pub use upstream::{UpstreamManager, StartupPingResult, DcPingResult};

src/transport/upstream.rs

@@ -1,26 +1,128 @@
-//! Upstream Management
+//! Upstream Management with per-DC latency-weighted selection
 
 use std::net::{SocketAddr, IpAddr};
 use std::sync::Arc;
 use std::time::Duration;
 use tokio::net::TcpStream;
 use tokio::sync::RwLock;
+use tokio::time::Instant;
 use rand::Rng;
-use tracing::{debug, warn, error, info};
+use tracing::{debug, warn, info, trace};
 
 use crate::config::{UpstreamConfig, UpstreamType};
 use crate::error::{Result, ProxyError};
+use crate::protocol::constants::{TG_DATACENTERS_V4, TG_DATACENTERS_V6, TG_DATACENTER_PORT};
 use crate::transport::socket::create_outgoing_socket_bound;
 use crate::transport::socks::{connect_socks4, connect_socks5};
 
+/// Number of Telegram datacenters
+const NUM_DCS: usize = 5;
+
+// ============= RTT Tracking =============
+
+#[derive(Debug, Clone, Copy)]
+struct LatencyEma {
+    value_ms: Option<f64>,
+    alpha: f64,
+}
+
+impl LatencyEma {
+    const fn new(alpha: f64) -> Self {
+        Self { value_ms: None, alpha }
+    }
+    
+    fn update(&mut self, sample_ms: f64) {
+        self.value_ms = Some(match self.value_ms {
+            None => sample_ms,
+            Some(prev) => prev * (1.0 - self.alpha) + sample_ms * self.alpha,
+        });
+    }
+    
+    fn get(&self) -> Option<f64> {
+        self.value_ms
+    }
+}
+
+// ============= Upstream State =============
+
 #[derive(Debug)]
 struct UpstreamState {
     config: UpstreamConfig,
     healthy: bool,
     fails: u32,
     last_check: std::time::Instant,
+    /// Per-DC latency EMA (index 0 = DC1, index 4 = DC5)
+    dc_latency: [LatencyEma; NUM_DCS],
 }
 
+impl UpstreamState {
+    fn new(config: UpstreamConfig) -> Self {
+        Self {
+            config,
+            healthy: true,
+            fails: 0,
+            last_check: std::time::Instant::now(),
+            dc_latency: [LatencyEma::new(0.3); NUM_DCS],
+        }
+    }
+    
+    /// Map DC index to latency array slot (0..NUM_DCS).
+    ///
+    /// Matches the C implementation's `mf_cluster_lookup` behavior:
+    /// - Standard DCs ±1..±5 → direct mapping to array index 0..4
+    /// - Unknown DCs (CDN, media, etc.) → default DC slot (index 1 = DC 2)
+    ///   This matches Telegram's `default 2;` in proxy-multi.conf.
+    /// - There is NO modular arithmetic in the C implementation.
+    fn dc_array_idx(dc_idx: i16) -> Option<usize> {
+        let abs_dc = dc_idx.unsigned_abs() as usize;
+        if abs_dc == 0 {
+            return None;
+        }
+        if abs_dc >= 1 && abs_dc <= NUM_DCS {
+            Some(abs_dc - 1)
+        } else {
+            // Unknown DC → default cluster (DC 2, index 1)
+            // Same as C: mf_cluster_lookup returns default_cluster
+            Some(1)
+        }
+    }
+    
+    /// Get latency for a specific DC, falling back to average across all known DCs
+    fn effective_latency(&self, dc_idx: Option<i16>) -> Option<f64> {
+        // Try DC-specific latency first
+        if let Some(di) = dc_idx.and_then(Self::dc_array_idx) {
+            if let Some(ms) = self.dc_latency[di].get() {
+                return Some(ms);
+            }
+        }
+        
+        // Fallback: average of all known DC latencies
+        let (sum, count) = self.dc_latency.iter()
+            .filter_map(|l| l.get())
+            .fold((0.0, 0u32), |(s, c), v| (s + v, c + 1));
+        
+        if count > 0 { Some(sum / count as f64) } else { None }
+    }
+}
+
+/// Result of a single DC ping
+#[derive(Debug, Clone)]
+pub struct DcPingResult {
+    pub dc_idx: usize,
+    pub dc_addr: SocketAddr,
+    pub rtt_ms: Option<f64>,
+    pub error: Option<String>,
+}
+
+/// Result of startup ping for one upstream
+#[derive(Debug, Clone)]
+pub struct StartupPingResult {
+    pub results: Vec<DcPingResult>,
+    pub upstream_name: String,
+}
+
+// ============= Upstream Manager =============
+
 #[derive(Clone)]
 pub struct UpstreamManager {
     upstreams: Arc<RwLock<Vec<UpstreamState>>>,
@@ -30,12 +132,7 @@ impl UpstreamManager {
     pub fn new(configs: Vec<UpstreamConfig>) -> Self {
         let states = configs.into_iter()
             .filter(|c| c.enabled)
-            .map(|c| UpstreamState {
-                config: c,
-                healthy: true, // Optimistic start
-                fails: 0,
-                last_check: std::time::Instant::now(),
-            })
+            .map(UpstreamState::new)
             .collect();
             
         Self {
@@ -43,48 +140,78 @@ impl UpstreamManager {
         }
     }
     
-    /// Select an upstream using Weighted Round Robin (simplified)
-    async fn select_upstream(&self) -> Option<usize> {
+    /// Select upstream using latency-weighted random selection.
+    ///
+    /// `effective_weight = config_weight × latency_factor`
+    ///
+    /// where `latency_factor = 1000 / latency_ms` if latency is known,
+    /// or `1.0` if no latency data is available.
+    ///
+    /// This means a 50ms upstream gets factor 20, a 200ms upstream gets
+    /// factor 5 — the faster route is 4× more likely to be chosen
+    /// (all else being equal).
+    async fn select_upstream(&self, dc_idx: Option<i16>) -> Option<usize> {
         let upstreams = self.upstreams.read().await;
         if upstreams.is_empty() {
             return None;
         }
 
-        let healthy_indices: Vec<usize> = upstreams.iter()
+        let healthy: Vec<usize> = upstreams.iter()
             .enumerate()
             .filter(|(_, u)| u.healthy)
             .map(|(i, _)| i)
             .collect();
             
-        if healthy_indices.is_empty() {
-            // If all unhealthy, try any random one
-            return Some(rand::thread_rng().gen_range(0..upstreams.len()));
+        if healthy.is_empty() {
+            // All unhealthy — pick any
+            return Some(rand::rng().gen_range(0..upstreams.len()));
         }
         
-        // Weighted selection
-        let total_weight: u32 = healthy_indices.iter()
-            .map(|&i| upstreams[i].config.weight as u32)
-            .sum();
-            
-        if total_weight == 0 {
-            return Some(healthy_indices[rand::thread_rng().gen_range(0..healthy_indices.len())]);
+        if healthy.len() == 1 {
+            return Some(healthy[0]);
         }
         
-        let mut choice = rand::thread_rng().gen_range(0..total_weight);
+        // Calculate latency-weighted scores
+        let weights: Vec<(usize, f64)> = healthy.iter().map(|&i| {
+            let base = upstreams[i].config.weight as f64;
+            let latency_factor = upstreams[i].effective_latency(dc_idx)
+                .map(|ms| if ms > 1.0 { 1000.0 / ms } else { 1000.0 })
+                .unwrap_or(1.0);
             
-        for &idx in &healthy_indices {
-            let weight = upstreams[idx].config.weight as u32;
+            (i, base * latency_factor)
+        }).collect();
+        
+        let total: f64 = weights.iter().map(|(_, w)| w).sum();
+        
+        if total <= 0.0 {
+            return Some(healthy[rand::rng().gen_range(0..healthy.len())]);
+        }
+        
+        let mut choice: f64 = rand::rng().gen_range(0.0..total);
+        
+        for &(idx, weight) in &weights {
             if choice < weight {
+                trace!(
+                    upstream = idx,
+                    dc = ?dc_idx,
+                    weight = format!("{:.2}", weight),
+                    total = format!("{:.2}", total),
+                    "Upstream selected"
+                );
                 return Some(idx);
             }
             choice -= weight;
         }
         
-        Some(healthy_indices[0])
+        Some(healthy[0])
     }
     
-    pub async fn connect(&self, target: SocketAddr) -> Result<TcpStream> {
-        let idx = self.select_upstream().await
+    /// Connect to target through a selected upstream.
+    ///
+    /// `dc_idx` is used for latency-based upstream selection and RTT tracking.
+    /// Pass `None` if DC index is unknown.
+    pub async fn connect(&self, target: SocketAddr, dc_idx: Option<i16>) -> Result<TcpStream> {
+        let idx = self.select_upstream(dc_idx).await
             .ok_or_else(|| ProxyError::Config("No upstreams available".to_string()))?;
             
         let upstream = {
@@ -92,28 +219,34 @@ impl UpstreamManager {
             guard[idx].config.clone()
         };
         
+        let start = Instant::now();
+        
         match self.connect_via_upstream(&upstream, target).await {
             Ok(stream) => {
-                // Mark success
+                let rtt_ms = start.elapsed().as_secs_f64() * 1000.0;
                 let mut guard = self.upstreams.write().await;
                 if let Some(u) = guard.get_mut(idx) {
                     if !u.healthy {
-                        debug!("Upstream recovered: {:?}", u.config);
+                        debug!(rtt_ms = format!("{:.1}", rtt_ms), "Upstream recovered");
                     }
                     u.healthy = true;
                     u.fails = 0;
+                    
+                    // Store per-DC latency
+                    if let Some(di) = dc_idx.and_then(UpstreamState::dc_array_idx) {
+                        u.dc_latency[di].update(rtt_ms);
+                    }
                 }
                 Ok(stream)
             },
             Err(e) => {
-                // Mark failure
                 let mut guard = self.upstreams.write().await;
                 if let Some(u) = guard.get_mut(idx) {
                     u.fails += 1;
-                    warn!("Failed to connect via upstream {:?}: {}. Fails: {}", u.config, e, u.fails);
+                    warn!(fails = u.fails, "Upstream failed: {}", e);
                     if u.fails > 3 {
                         u.healthy = false;
-                        warn!("Upstream disabled due to failures: {:?}", u.config);
+                        warn!("Upstream marked unhealthy");
                     }
                 }
                 Err(e)
@@ -129,18 +262,16 @@ impl UpstreamManager {
                 
                 let socket = create_outgoing_socket_bound(target, bind_ip)?;
                 
-                // Non-blocking connect logic
                 socket.set_nonblocking(true)?;
                 match socket.connect(&target.into()) {
                     Ok(()) => {},
-                    Err(err) if err.raw_os_error() == Some(115) || err.kind() == std::io::ErrorKind::WouldBlock => {},
+                    Err(err) if err.raw_os_error() == Some(libc::EINPROGRESS) || err.kind() == std::io::ErrorKind::WouldBlock => {},
                     Err(err) => return Err(ProxyError::Io(err)),
                 }
                 
                 let std_stream: std::net::TcpStream = socket.into();
                 let stream = TcpStream::from_std(std_stream)?;
                 
-                // Wait for connection to complete
                 stream.writable().await?;
                 if let Some(e) = stream.take_error()? {
                     return Err(ProxyError::Io(e));
@@ -149,8 +280,6 @@ impl UpstreamManager {
                 Ok(stream)
             },
             UpstreamType::Socks4 { address, interface, user_id } => {
-                info!("Connecting to target {} via SOCKS4 proxy {}", target, address);
-                
                 let proxy_addr: SocketAddr = address.parse()
                     .map_err(|_| ProxyError::Config("Invalid SOCKS4 address".to_string()))?;
                     
@@ -159,18 +288,16 @@ impl UpstreamManager {
                 
                 let socket = create_outgoing_socket_bound(proxy_addr, bind_ip)?;
                 
-                // Non-blocking connect logic
                 socket.set_nonblocking(true)?;
                 match socket.connect(&proxy_addr.into()) {
                     Ok(()) => {},
-                    Err(err) if err.raw_os_error() == Some(115) || err.kind() == std::io::ErrorKind::WouldBlock => {},
+                    Err(err) if err.raw_os_error() == Some(libc::EINPROGRESS) || err.kind() == std::io::ErrorKind::WouldBlock => {},
                     Err(err) => return Err(ProxyError::Io(err)),
                 }
                 
                 let std_stream: std::net::TcpStream = socket.into();
                 let mut stream = TcpStream::from_std(std_stream)?;
                 
-                // Wait for connection to complete
                 stream.writable().await?;
                 if let Some(e) = stream.take_error()? {
                     return Err(ProxyError::Io(e));
@@ -180,8 +307,6 @@ impl UpstreamManager {
                 Ok(stream)
             },
             UpstreamType::Socks5 { address, interface, username, password } => {
-                info!("Connecting to target {} via SOCKS5 proxy {}", target, address);
-                
                 let proxy_addr: SocketAddr = address.parse()
                     .map_err(|_| ProxyError::Config("Invalid SOCKS5 address".to_string()))?;
                     
@@ -190,18 +315,16 @@ impl UpstreamManager {
                 
                 let socket = create_outgoing_socket_bound(proxy_addr, bind_ip)?;
                 
-                // Non-blocking connect logic
                 socket.set_nonblocking(true)?;
                 match socket.connect(&proxy_addr.into()) {
                     Ok(()) => {},
-                    Err(err) if err.raw_os_error() == Some(115) || err.kind() == std::io::ErrorKind::WouldBlock => {},
+                    Err(err) if err.raw_os_error() == Some(libc::EINPROGRESS) || err.kind() == std::io::ErrorKind::WouldBlock => {},
                     Err(err) => return Err(ProxyError::Io(err)),
                 }
                 
                 let std_stream: std::net::TcpStream = socket.into();
                 let mut stream = TcpStream::from_std(std_stream)?;
                 
-                // Wait for connection to complete
                 stream.writable().await?;
                 if let Some(e) = stream.take_error()? {
                     return Err(ProxyError::Io(e));
@@ -213,13 +336,100 @@ impl UpstreamManager {
         }
     }
     
-    /// Background task to check health
-    pub async fn run_health_checks(&self) {
-        // Simple TCP connect check to a known stable DC (e.g. 149.154.167.50:443 - DC2)
-        let check_target: SocketAddr = "149.154.167.50:443".parse().unwrap();
+    // ============= Startup Ping =============
+    
+    /// Ping all Telegram DCs through all upstreams.
+    pub async fn ping_all_dcs(&self, prefer_ipv6: bool) -> Vec<StartupPingResult> {
+        let upstreams: Vec<(usize, UpstreamConfig)> = {
+            let guard = self.upstreams.read().await;
+            guard.iter().enumerate()
+                .map(|(i, u)| (i, u.config.clone()))
+                .collect()
+        };
+        
+        let datacenters = if prefer_ipv6 { &*TG_DATACENTERS_V6 } else { &*TG_DATACENTERS_V4 };
+        
+        let mut all_results = Vec::new();
+        
+        for (upstream_idx, upstream_config) in &upstreams {
+            let upstream_name = match &upstream_config.upstream_type {
+                UpstreamType::Direct { interface } => {
+                    format!("direct{}", interface.as_ref().map(|i| format!(" ({})", i)).unwrap_or_default())
+                }
+                UpstreamType::Socks4 { address, .. } => format!("socks4://{}", address),
+                UpstreamType::Socks5 { address, .. } => format!("socks5://{}", address),
+            };
+            
+            let mut dc_results = Vec::new();
+            
+            for (dc_zero_idx, dc_ip) in datacenters.iter().enumerate() {
+                let dc_addr = SocketAddr::new(*dc_ip, TG_DATACENTER_PORT);
+                
+                let ping_result = tokio::time::timeout(
+                    Duration::from_secs(5),
+                    self.ping_single_dc(upstream_config, dc_addr)
+                ).await;
+                
+                let result = match ping_result {
+                    Ok(Ok(rtt_ms)) => {
+                        // Store per-DC latency
+                        let mut guard = self.upstreams.write().await;
+                        if let Some(u) = guard.get_mut(*upstream_idx) {
+                            u.dc_latency[dc_zero_idx].update(rtt_ms);
+                        }
+                        DcPingResult {
+                            dc_idx: dc_zero_idx + 1,
+                            dc_addr,
+                            rtt_ms: Some(rtt_ms),
+                            error: None,
+                        }
+                    }
+                    Ok(Err(e)) => DcPingResult {
+                        dc_idx: dc_zero_idx + 1,
+                        dc_addr,
+                        rtt_ms: None,
+                        error: Some(e.to_string()),
+                    },
+                    Err(_) => DcPingResult {
+                        dc_idx: dc_zero_idx + 1,
+                        dc_addr,
+                        rtt_ms: None,
+                        error: Some("timeout (5s)".to_string()),
+                    },
+                };
+                
+                dc_results.push(result);
+            }
+            
+            all_results.push(StartupPingResult {
+                results: dc_results,
+                upstream_name,
+            });
+        }
+        
+        all_results
+    }
+    
+    async fn ping_single_dc(&self, config: &UpstreamConfig, target: SocketAddr) -> Result<f64> {
+        let start = Instant::now();
+        let _stream = self.connect_via_upstream(config, target).await?;
+        Ok(start.elapsed().as_secs_f64() * 1000.0)
+    }
+    
+    // ============= Health Checks =============
+    
+    /// Background health check: rotates through DCs, 30s interval.
+    pub async fn run_health_checks(&self, prefer_ipv6: bool) {
+        let datacenters = if prefer_ipv6 { &*TG_DATACENTERS_V6 } else { &*TG_DATACENTERS_V4 };
+        let mut dc_rotation = 0usize;
         
         loop {
-            tokio::time::sleep(Duration::from_secs(60)).await;
+            tokio::time::sleep(Duration::from_secs(30)).await;
+            
+            let dc_zero_idx = dc_rotation % datacenters.len();
+            dc_rotation += 1;
+            
+            let check_target = SocketAddr::new(datacenters[dc_zero_idx], TG_DATACENTER_PORT);
             
             let count = self.upstreams.read().await.len();
             for i in 0..count {
@@ -228,6 +438,7 @@ impl UpstreamManager {
                     guard[i].config.clone()
                 };
                 
+                let start = Instant::now();
                 let result = tokio::time::timeout(
                     Duration::from_secs(10),
                     self.connect_via_upstream(&config, check_target)
@@ -238,18 +449,36 @@ impl UpstreamManager {
                 
                 match result {
                     Ok(Ok(_stream)) => {
+                        let rtt_ms = start.elapsed().as_secs_f64() * 1000.0;
+                        u.dc_latency[dc_zero_idx].update(rtt_ms);
+                        
                         if !u.healthy {
-                            debug!("Upstream recovered: {:?}", u.config);
+                            info!(
+                                rtt = format!("{:.0}ms", rtt_ms),
+                                dc = dc_zero_idx + 1,
+                                "Upstream recovered"
+                            );
                         }
                         u.healthy = true;
                         u.fails = 0;
                     }
                     Ok(Err(e)) => {
-                        debug!("Health check failed for {:?}: {}", u.config, e);
-                        // Don't mark unhealthy immediately in background check
+                        u.fails += 1;
+                        debug!(dc = dc_zero_idx + 1, fails = u.fails,
+                            "Health check failed: {}", e);
+                        if u.fails > 3 {
+                            u.healthy = false;
+                            warn!("Upstream unhealthy (fails)");
+                        }
                     }
                     Err(_) => {
-                        debug!("Health check timeout for {:?}", u.config);
+                        u.fails += 1;
+                        debug!(dc = dc_zero_idx + 1, fails = u.fails,
+                            "Health check timeout");
+                        if u.fails > 3 {
+                            u.healthy = false;
+                            warn!("Upstream unhealthy (timeout)");
+                        }
                     }
                 }
                 u.last_check = std::time::Instant::now();