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Key derivation + me_health_monitor + QuickACK

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Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>
This commit is contained in:
Alexey
2026-02-13 12:51:49 +03:00
parent a494dfa9eb
commit f1c1f42de8
4 changed files with 1771 additions and 1018 deletions
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930
src/proxy/client.rs
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@@ -1,403 +1,583 @@
//! Client Handler
use std::net::SocketAddr;
use std::sync::Arc;
use std::time::Duration;
use tokio::net::TcpStream;
use tokio::io::{AsyncRead, AsyncWrite, AsyncReadExt, AsyncWriteExt};
use tokio::time::timeout;
use tracing::{debug, info, warn, error, trace};
use crate::config::ProxyConfig;
use crate::error::{ProxyError, Result, HandshakeResult};
use crate::protocol::constants::*;
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, SecureRandom};
use crate::proxy::handshake::{
handle_tls_handshake, handle_mtproto_handshake,
HandshakeSuccess, generate_tg_nonce, encrypt_tg_nonce,
};
use crate::proxy::relay::relay_bidirectional;
use crate::proxy::masking::handle_bad_client;
pub struct ClientHandler;
pub struct RunningClientHandler {
stream: TcpStream,
peer: SocketAddr,
config: Arc<ProxyConfig>,
stats: Arc<Stats>,
replay_checker: Arc<ReplayChecker>,
upstream_manager: Arc<UpstreamManager>,
buffer_pool: Arc<BufferPool>,
rng: Arc<SecureRandom>,
}
impl ClientHandler {
pub fn new(
use std::net::SocketAddr;
use std::sync::Arc;
use std::time::Duration;
use tokio::net::TcpStream;
use tokio::io::{AsyncRead, AsyncWrite, AsyncReadExt, AsyncWriteExt};
use tokio::time::timeout;
use tracing::{debug, info, warn, error, trace};
use crate::config::ProxyConfig;
use crate::error::{ProxyError, Result, HandshakeResult};
use crate::protocol::constants::*;
use crate::protocol::tls;
use crate::stats::{Stats, ReplayChecker};
use crate::transport::{configure_client_socket, UpstreamManager};
use crate::transport::middle_proxy::{MePool, MeResponse};
use crate::stream::{CryptoReader, CryptoWriter, FakeTlsReader, FakeTlsWriter, BufferPool};
use crate::crypto::{AesCtr, SecureRandom};
use crate::proxy::handshake::{
handle_tls_handshake, handle_mtproto_handshake,
HandshakeSuccess, generate_tg_nonce, encrypt_tg_nonce,
};
use crate::proxy::relay::relay_bidirectional;
use crate::proxy::masking::handle_bad_client;
pub struct ClientHandler;
pub struct RunningClientHandler {
stream: TcpStream,
peer: SocketAddr,
config: Arc<ProxyConfig>,
stats: Arc<Stats>,
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, rng,
}
}
}
impl RunningClientHandler {
pub async fn run(mut self) -> Result<()> {
self.stats.increment_connects_all();
let peer = self.peer;
debug!(peer = %peer, "New connection");
if let Err(e) = configure_client_socket(
&self.stream,
self.config.timeouts.client_keepalive,
self.config.timeouts.client_ack,
) {
debug!(peer = %peer, error = %e, "Failed to configure client socket");
}
let handshake_timeout = Duration::from_secs(self.config.timeouts.client_handshake);
let stats = self.stats.clone();
let result = timeout(handshake_timeout, self.do_handshake()).await;
match result {
Ok(Ok(())) => {
debug!(peer = %peer, "Connection handled successfully");
Ok(())
}
Ok(Err(e)) => {
debug!(peer = %peer, error = %e, "Handshake failed");
Err(e)
}
Err(_) => {
stats.increment_handshake_timeouts();
debug!(peer = %peer, "Handshake timeout");
Err(ProxyError::TgHandshakeTimeout)
}
}
}
async fn do_handshake(mut self) -> Result<()> {
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, "Handshake type detected");
if is_tls {
self.handle_tls_client(first_bytes).await
} else {
self.handle_direct_client(first_bytes).await
}
}
async fn handle_tls_client(mut self, first_bytes: [u8; 5]) -> Result<()> {
let peer = self.peer;
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");
if tls_len < 512 {
debug!(peer = %peer, tls_len = tls_len, "TLS handshake too short");
self.stats.increment_connects_bad();
let (reader, writer) = self.stream.into_split();
handle_bad_client(reader, writer, &first_bytes, &self.config).await;
return Ok(());
}
let mut handshake = vec![0u8; 5 + tls_len];
handshake[..5].copy_from_slice(&first_bytes);
self.stream.read_exact(&mut handshake[5..]).await?;
let config = self.config.clone();
let replay_checker = self.replay_checker.clone();
let stats = self.stats.clone();
let buffer_pool = self.buffer_pool.clone();
let (read_half, write_half) = self.stream.into_split();
let (mut tls_reader, tls_writer, _tls_user) = match handle_tls_handshake(
&handshake, read_half, write_half, peer,
&config, &replay_checker, &self.rng,
).await {
HandshakeResult::Success(result) => result,
HandshakeResult::BadClient { reader, writer } => {
stats.increment_connects_bad();
handle_bad_client(reader, writer, &handshake, &config).await;
return Ok(());
}
HandshakeResult::Error(e) => return Err(e),
};
debug!(peer = %peer, "Reading MTProto handshake through TLS");
let mtproto_data = tls_reader.read_exact(HANDSHAKE_LEN).await?;
let mtproto_handshake: [u8; HANDSHAKE_LEN] = mtproto_data[..].try_into()
.map_err(|_| ProxyError::InvalidHandshake("Short MTProto handshake".into()))?;
let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
&mtproto_handshake, tls_reader, tls_writer, peer,
&config, &replay_checker, true,
).await {
HandshakeResult::Success(result) => result,
HandshakeResult::BadClient { reader: _, writer: _ } => {
stats.increment_connects_bad();
debug!(peer = %peer, "Valid TLS but invalid MTProto handshake");
return Ok(());
}
HandshakeResult::Error(e) => return Err(e),
};
Self::handle_authenticated_static(
crypto_reader, crypto_writer, success,
self.upstream_manager, self.stats, self.config,
buffer_pool, self.rng,
).await
}
async fn handle_direct_client(mut self, first_bytes: [u8; 5]) -> Result<()> {
let peer = self.peer;
if !self.config.general.modes.classic && !self.config.general.modes.secure {
debug!(peer = %peer, "Non-TLS modes disabled");
self.stats.increment_connects_bad();
let (reader, writer) = self.stream.into_split();
handle_bad_client(reader, writer, &first_bytes, &self.config).await;
return Ok(());
}
let mut handshake = [0u8; HANDSHAKE_LEN];
handshake[..5].copy_from_slice(&first_bytes);
self.stream.read_exact(&mut handshake[5..]).await?;
let config = self.config.clone();
let replay_checker = self.replay_checker.clone();
let stats = self.stats.clone();
let buffer_pool = self.buffer_pool.clone();
let (read_half, write_half) = self.stream.into_split();
let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
&handshake, read_half, write_half, peer,
&config, &replay_checker, false,
).await {
HandshakeResult::Success(result) => result,
HandshakeResult::BadClient { reader, writer } => {
stats.increment_connects_bad();
handle_bad_client(reader, writer, &handshake, &config).await;
return Ok(());
}
HandshakeResult::Error(e) => return Err(e),
};
Self::handle_authenticated_static(
crypto_reader, crypto_writer, success,
self.upstream_manager, self.stats, self.config,
buffer_pool, self.rng,
).await
}
async fn handle_authenticated_static<R, W>(
client_reader: CryptoReader<R>,
client_writer: CryptoWriter<W>,
success: HandshakeSuccess,
upstream_manager: Arc<UpstreamManager>,
stats: Arc<Stats>,
config: Arc<ProxyConfig>,
buffer_pool: Arc<BufferPool>,
rng: Arc<SecureRandom>,
) -> Result<()>
where
R: AsyncRead + Unpin + Send + 'static,
W: AsyncWrite + Unpin + Send + 'static,
{
let user = &success.user;
if let Err(e) = Self::check_user_limits_static(user, &config, &stats) {
warn!(user = %user, error = %e, "User limit exceeded");
return Err(e);
}
let dc_addr = Self::get_dc_addr_static(success.dc_idx, &config)?;
info!(
user = %user,
peer = %success.peer,
dc = success.dc_idx,
dc_addr = %dc_addr,
proto = ?success.proto_tag,
"Connecting to Telegram"
);
// 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, performing TG handshake");
let (tg_reader, tg_writer) = Self::do_tg_handshake_static(
tg_stream, &success, &config, rng.as_ref(),
).await?;
debug!(peer = %success.peer, "TG handshake complete, starting relay");
stats.increment_user_connects(user);
stats.increment_user_curr_connects(user);
let relay_result = relay_bidirectional(
client_reader, client_writer,
tg_reader, tg_writer,
user, Arc::clone(&stats), buffer_pool,
).await;
stats.decrement_user_curr_connects(user);
match &relay_result {
Ok(()) => debug!(user = %user, "Relay completed"),
Err(e) => debug!(user = %user, error = %e, "Relay ended with error"),
}
relay_result
me_pool: Option<Arc<MePool>>,
}
fn check_user_limits_static(user: &str, config: &ProxyConfig, stats: &Stats) -> Result<()> {
if let Some(expiration) = config.access.user_expirations.get(user) {
if chrono::Utc::now() > *expiration {
return Err(ProxyError::UserExpired { user: user.to_string() });
impl ClientHandler {
pub fn new(
stream: TcpStream,
peer: SocketAddr,
config: Arc<ProxyConfig>,
stats: Arc<Stats>,
upstream_manager: Arc<UpstreamManager>,
replay_checker: Arc<ReplayChecker>,
buffer_pool: Arc<BufferPool>,
rng: Arc<SecureRandom>,
me_pool: Option<Arc<MePool>>,
) -> RunningClientHandler {
RunningClientHandler {
stream, peer, config, stats, replay_checker,
upstream_manager, buffer_pool, rng, me_pool,
}
}
if let Some(limit) = config.access.user_max_tcp_conns.get(user) {
if stats.get_user_curr_connects(user) >= *limit as u64 {
return Err(ProxyError::ConnectionLimitExceeded { user: user.to_string() });
}
}
if let Some(quota) = config.access.user_data_quota.get(user) {
if stats.get_user_total_octets(user) >= *quota {
return Err(ProxyError::DataQuotaExceeded { user: user.to_string() });
}
}
Ok(())
}
/// 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 datacenters = if config.general.prefer_ipv6 {
&*TG_DATACENTERS_V6
} else {
&*TG_DATACENTERS_V4
};
impl RunningClientHandler {
pub async fn run(mut self) -> Result<()> {
self.stats.increment_connects_all();
let num_dcs = datacenters.len(); // 5
let peer = self.peer;
debug!(peer = %peer, "New connection");
// === 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);
if let Err(e) = configure_client_socket(
&self.stream,
self.config.timeouts.client_keepalive,
self.config.timeouts.client_ack,
) {
debug!(peer = %peer, error = %e, "Failed to configure client socket");
}
let handshake_timeout = Duration::from_secs(self.config.timeouts.client_handshake);
let stats = self.stats.clone();
let result = timeout(handshake_timeout, self.do_handshake()).await;
match result {
Ok(Ok(())) => {
debug!(peer = %peer, "Connection handled successfully");
Ok(())
}
Ok(Err(e)) => {
debug!(peer = %peer, error = %e, "Handshake failed");
Err(e)
}
Err(_) => {
warn!(dc_idx = dc_idx, addr_str = %addr_str,
"Invalid DC override address in config, ignoring");
stats.increment_handshake_timeouts();
debug!(peer = %peer, "Handshake timeout");
Err(ProxyError::TgHandshakeTimeout)
}
}
}
// === 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));
async fn do_handshake(mut self) -> Result<()> {
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, "Handshake type detected");
if is_tls {
self.handle_tls_client(first_bytes).await
} else {
self.handle_direct_client(first_bytes).await
}
}
// === 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;`
};
async fn handle_tls_client(mut self, first_bytes: [u8; 5]) -> Result<()> {
let peer = self.peer;
info!(
original_dc = dc_idx,
fallback_dc = (fallback_idx + 1) as u16,
fallback_addr = %datacenters[fallback_idx],
"Special DC ---> default_cluster"
);
let tls_len = u16::from_be_bytes([first_bytes[3], first_bytes[4]]) as usize;
Ok(SocketAddr::new(datacenters[fallback_idx], TG_DATACENTER_PORT))
debug!(peer = %peer, tls_len = tls_len, "Reading TLS handshake");
if tls_len < 512 {
debug!(peer = %peer, tls_len = tls_len, "TLS handshake too short");
self.stats.increment_connects_bad();
let (reader, writer) = self.stream.into_split();
handle_bad_client(reader, writer, &first_bytes, &self.config).await;
return Ok(());
}
let mut handshake = vec![0u8; 5 + tls_len];
handshake[..5].copy_from_slice(&first_bytes);
self.stream.read_exact(&mut handshake[5..]).await?;
let config = self.config.clone();
let replay_checker = self.replay_checker.clone();
let stats = self.stats.clone();
let buffer_pool = self.buffer_pool.clone();
let (read_half, write_half) = self.stream.into_split();
let (mut tls_reader, tls_writer, _tls_user) = match handle_tls_handshake(
&handshake, read_half, write_half, peer,
&config, &replay_checker, &self.rng,
).await {
HandshakeResult::Success(result) => result,
HandshakeResult::BadClient { reader, writer } => {
stats.increment_connects_bad();
handle_bad_client(reader, writer, &handshake, &config).await;
return Ok(());
}
HandshakeResult::Error(e) => return Err(e),
};
debug!(peer = %peer, "Reading MTProto handshake through TLS");
let mtproto_data = tls_reader.read_exact(HANDSHAKE_LEN).await?;
let mtproto_handshake: [u8; HANDSHAKE_LEN] = mtproto_data[..].try_into()
.map_err(|_| ProxyError::InvalidHandshake("Short MTProto handshake".into()))?;
let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
&mtproto_handshake, tls_reader, tls_writer, peer,
&config, &replay_checker, true,
).await {
HandshakeResult::Success(result) => result,
HandshakeResult::BadClient { reader: _, writer: _ } => {
stats.increment_connects_bad();
debug!(peer = %peer, "Valid TLS but invalid MTProto handshake");
return Ok(());
}
HandshakeResult::Error(e) => return Err(e),
};
Self::handle_authenticated_static(
crypto_reader, crypto_writer, success,
self.upstream_manager, self.stats, self.config,
buffer_pool, self.rng, self.me_pool,
).await
}
async fn handle_direct_client(mut self, first_bytes: [u8; 5]) -> Result<()> {
let peer = self.peer;
if !self.config.general.modes.classic && !self.config.general.modes.secure {
debug!(peer = %peer, "Non-TLS modes disabled");
self.stats.increment_connects_bad();
let (reader, writer) = self.stream.into_split();
handle_bad_client(reader, writer, &first_bytes, &self.config).await;
return Ok(());
}
let mut handshake = [0u8; HANDSHAKE_LEN];
handshake[..5].copy_from_slice(&first_bytes);
self.stream.read_exact(&mut handshake[5..]).await?;
let config = self.config.clone();
let replay_checker = self.replay_checker.clone();
let stats = self.stats.clone();
let buffer_pool = self.buffer_pool.clone();
let (read_half, write_half) = self.stream.into_split();
let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
&handshake, read_half, write_half, peer,
&config, &replay_checker, false,
).await {
HandshakeResult::Success(result) => result,
HandshakeResult::BadClient { reader, writer } => {
stats.increment_connects_bad();
handle_bad_client(reader, writer, &handshake, &config).await;
return Ok(());
}
HandshakeResult::Error(e) => return Err(e),
};
Self::handle_authenticated_static(
crypto_reader, crypto_writer, success,
self.upstream_manager, self.stats, self.config,
buffer_pool, self.rng, self.me_pool,
).await
}
/// Main dispatch after successful handshake.
/// Two modes:
/// - Direct: TCP relay to TG DC (existing behavior)
/// - Middle Proxy: RPC multiplex through ME pool (new — supports CDN DCs)
async fn handle_authenticated_static<R, W>(
client_reader: CryptoReader<R>,
client_writer: CryptoWriter<W>,
success: HandshakeSuccess,
upstream_manager: Arc<UpstreamManager>,
stats: Arc<Stats>,
config: Arc<ProxyConfig>,
buffer_pool: Arc<BufferPool>,
rng: Arc<SecureRandom>,
me_pool: Option<Arc<MePool>>,
) -> Result<()>
where
R: AsyncRead + Unpin + Send + 'static,
W: AsyncWrite + Unpin + Send + 'static,
{
let user = &success.user;
if let Err(e) = Self::check_user_limits_static(user, &config, &stats) {
warn!(user = %user, error = %e, "User limit exceeded");
return Err(e);
}
// Decide: middle proxy or direct
if config.general.use_middle_proxy {
if let Some(ref pool) = me_pool {
return Self::handle_via_middle_proxy(
client_reader, client_writer, success,
pool.clone(), stats, config, buffer_pool,
).await;
}
warn!("use_middle_proxy=true but MePool not initialized, falling back to direct");
}
// Direct mode (original behavior)
Self::handle_via_direct(
client_reader, client_writer, success,
upstream_manager, stats, config, buffer_pool, rng,
).await
}
// =====================================================================
// Direct mode — TCP relay to Telegram DC
// =====================================================================
async fn handle_via_direct<R, W>(
client_reader: CryptoReader<R>,
client_writer: CryptoWriter<W>,
success: HandshakeSuccess,
upstream_manager: Arc<UpstreamManager>,
stats: Arc<Stats>,
config: Arc<ProxyConfig>,
buffer_pool: Arc<BufferPool>,
rng: Arc<SecureRandom>,
) -> Result<()>
where
R: AsyncRead + Unpin + Send + 'static,
W: AsyncWrite + Unpin + Send + 'static,
{
let user = &success.user;
let dc_addr = Self::get_dc_addr_static(success.dc_idx, &config)?;
info!(
user = %user,
peer = %success.peer,
dc = success.dc_idx,
dc_addr = %dc_addr,
proto = ?success.proto_tag,
mode = "direct",
"Connecting to Telegram DC"
);
let tg_stream = upstream_manager.connect(dc_addr, Some(success.dc_idx)).await?;
debug!(peer = %success.peer, dc_addr = %dc_addr, "Connected, performing TG handshake");
let (tg_reader, tg_writer) = Self::do_tg_handshake_static(
tg_stream, &success, &config, rng.as_ref(),
).await?;
debug!(peer = %success.peer, "TG handshake complete, starting relay");
stats.increment_user_connects(user);
stats.increment_user_curr_connects(user);
let relay_result = relay_bidirectional(
client_reader, client_writer,
tg_reader, tg_writer,
user, Arc::clone(&stats), buffer_pool,
).await;
stats.decrement_user_curr_connects(user);
match &relay_result {
Ok(()) => debug!(user = %user, "Direct relay completed"),
Err(e) => debug!(user = %user, error = %e, "Direct relay ended with error"),
}
relay_result
}
// =====================================================================
// Middle Proxy mode — RPC multiplex through ME pool
// =====================================================================
/// Middle Proxy RPC relay
///
/// Architecture (matches C MTProxy):
/// ```text
/// Client ←AES-CTR→ [telemt] ←RPC/AES-CBC→ ME ←internal→ DC (any, incl CDN 203)
/// ```
///
/// Key difference from direct mode:
/// - No per-client TCP to DC; all clients share ME pool connections
/// - ME internally routes to correct DC based on client's encrypted auth_key_id
/// - CDN DCs (203+) work because ME knows their internal addresses
/// - We pass raw client MTProto bytes in RPC_PROXY_REQ envelope
/// - ME returns responses in RPC_PROXY_ANS envelope
async fn handle_via_middle_proxy<R, W>(
mut client_reader: CryptoReader<R>,
mut client_writer: CryptoWriter<W>,
success: HandshakeSuccess,
me_pool: Arc<MePool>,
stats: Arc<Stats>,
config: Arc<ProxyConfig>,
_buffer_pool: Arc<BufferPool>,
) -> Result<()>
where
R: AsyncRead + Unpin + Send + 'static,
W: AsyncWrite + Unpin + Send + 'static,
{
let user = success.user.clone();
let peer = success.peer;
info!(
user = %user,
peer = %peer,
dc = success.dc_idx,
proto = ?success.proto_tag,
mode = "middle_proxy",
"Routing via Middle-End"
);
// Register this client connection in ME demux registry
let (conn_id, mut me_rx) = me_pool.registry().register().await;
// Our listening address for RPC_PROXY_REQ metadata
let our_addr: SocketAddr = format!("0.0.0.0:{}", config.server.port)
.parse().unwrap_or_else(|_| "0.0.0.0:443".parse().unwrap());
stats.increment_user_connects(&user);
stats.increment_user_curr_connects(&user);
debug!(user = %user, conn_id, "ME relay started");
// Bidirectional relay loop: client ↔ ME pool
//
// C→S direction: read raw bytes from client_reader, wrap in RPC_PROXY_REQ, send via ME
// S→C direction: receive MeResponse::Data from registry channel, write to client_writer
//
// We use tokio::select! to handle both directions concurrently.
// Unlike direct mode (copy_bidirectional on two TCP streams),
// here one side is a channel (mpsc::Receiver), not a stream.
let mut client_buf = vec![0u8; 64 * 1024];
let mut client_closed = false;
let mut server_closed = false;
let result: Result<()> = loop {
tokio::select! {
// C→S: client sends data, we forward to ME
read_result = client_reader.read(&mut client_buf), if !client_closed => {
match read_result {
Ok(0) => {
debug!(conn_id, "Client EOF");
client_closed = true;
if server_closed { break Ok(()); }
// Signal ME to close this connection
let _ = me_pool.send_close(conn_id).await;
}
Ok(n) => {
trace!(conn_id, bytes = n, "C→ME");
stats.add_user_octets_from(&user, n as u64);
if let Err(e) = me_pool.send_proxy_req(
conn_id, peer, our_addr, &client_buf[..n]
).await {
break Err(e);
}
}
Err(e) => {
debug!(conn_id, error = %e, "Client read error");
break Err(ProxyError::Io(e));
}
}
}
// S→C: ME sends response, we forward to client
me_msg = me_rx.recv(), if !server_closed => {
match me_msg {
Some(MeResponse::Data(data)) => {
trace!(conn_id, bytes = data.len(), "ME→C");
stats.add_user_octets_to(&user, data.len() as u64);
if let Err(e) = client_writer.write_all(&data).await {
debug!(conn_id, error = %e, "Client write error");
break Err(ProxyError::Io(e));
}
if let Err(e) = client_writer.flush().await {
break Err(ProxyError::Io(e));
}
}
Some(MeResponse::Ack(_token)) => {
// QuickACK from ME — could forward to client as obfuscated ACK
// For now, just log
trace!(conn_id, "ME ACK (ignored)");
}
Some(MeResponse::Close) => {
debug!(conn_id, "ME sent CLOSE");
server_closed = true;
if client_closed { break Ok(()); }
}
None => {
// Channel closed — ME connection died
debug!(conn_id, "ME channel closed");
server_closed = true;
if client_closed { break Ok(()); }
break Err(ProxyError::Proxy("ME connection lost".into()));
}
}
}
// Both sides closed
else => {
break Ok(());
}
}
};
// Cleanup
debug!(user = %user, conn_id, "ME relay cleanup");
me_pool.registry().unregister(conn_id).await;
stats.decrement_user_curr_connects(&user);
match &result {
Ok(()) => debug!(user = %user, conn_id, "ME relay completed"),
Err(e) => debug!(user = %user, conn_id, error = %e, "ME relay error"),
}
result
}
// =====================================================================
// Helpers
// =====================================================================
fn check_user_limits_static(user: &str, config: &ProxyConfig, stats: &Stats) -> Result<()> {
if let Some(expiration) = config.access.user_expirations.get(user) {
if chrono::Utc::now() > *expiration {
return Err(ProxyError::UserExpired { user: user.to_string() });
}
}
if let Some(limit) = config.access.user_max_tcp_conns.get(user) {
if stats.get_user_curr_connects(user) >= *limit as u64 {
return Err(ProxyError::ConnectionLimitExceeded { user: user.to_string() });
}
}
if let Some(quota) = config.access.user_data_quota.get(user) {
if stats.get_user_total_octets(user) >= *quota {
return Err(ProxyError::DataQuotaExceeded { user: user.to_string() });
}
}
Ok(())
}
/// Resolve DC index to target address (used only in direct mode)
fn get_dc_addr_static(dc_idx: i16, config: &ProxyConfig) -> Result<SocketAddr> {
let datacenters = if config.general.prefer_ipv6 {
&*TG_DATACENTERS_V6
} else {
&*TG_DATACENTERS_V4
};
let num_dcs = datacenters.len();
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");
}
}
}
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));
}
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
};
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 obfuscated handshake with Telegram DC (direct mode only)
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>)> {
let (nonce, tg_enc_key, tg_enc_iv, tg_dec_key, tg_dec_iv) = generate_tg_nonce(
success.proto_tag,
success.dc_idx,
&success.dec_key,
success.dec_iv,
rng,
config.general.fast_mode,
);
let encrypted_nonce = encrypt_tg_nonce(&nonce);
debug!(
peer = %success.peer,
nonce_head = %hex::encode(&nonce[..16]),
"Sending nonce to Telegram"
);
stream.write_all(&encrypted_nonce).await?;
stream.flush().await?;
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);
Ok((
CryptoReader::new(read_half, decryptor),
CryptoWriter::new(write_half, encryptor),
))
}
}
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>)> {
let (nonce, tg_enc_key, tg_enc_iv, tg_dec_key, tg_dec_iv) = generate_tg_nonce(
success.proto_tag,
success.dc_idx,
&success.dec_key,
success.dec_iv,
rng,
config.general.fast_mode,
);
let encrypted_nonce = encrypt_tg_nonce(&nonce);
debug!(
peer = %success.peer,
nonce_head = %hex::encode(&nonce[..16]),
"Sending nonce to Telegram"
);
stream.write_all(&encrypted_nonce).await?;
stream.flush().await?;
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);
Ok((
CryptoReader::new(read_half, decryptor),
CryptoWriter::new(write_half, encryptor),
))
}
}