From d050c4794afac55997661a4995d87d3bda0e4b58 Mon Sep 17 00:00:00 2001
From: Alexey <247128645+axkurcom@users.noreply.github.com>
Date: Mon, 23 Feb 2026 00:50:10 +0300
Subject: [PATCH] Hotpath tunings

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>
---
 src/proxy/middle_relay.rs | 63 +++++++++++++++++++++++++++++----------
 1 file changed, 48 insertions(+), 15 deletions(-)

diff --git a/src/proxy/middle_relay.rs b/src/proxy/middle_relay.rs
index fe4e219..b7f22ae 100644
--- a/src/proxy/middle_relay.rs
+++ b/src/proxy/middle_relay.rs
@@ -2,7 +2,7 @@ use std::net::SocketAddr;
 use std::sync::Arc;
 
 use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
-use tokio::sync::oneshot;
+use tokio::sync::{mpsc, oneshot};
 use tracing::{debug, info, trace, warn};
 
 use crate::config::ProxyConfig;
@@ -14,6 +14,11 @@ use crate::stats::Stats;
 use crate::stream::{BufferPool, CryptoReader, CryptoWriter};
 use crate::transport::middle_proxy::{MePool, MeResponse, proto_flags_for_tag};
 
+enum C2MeCommand {
+    Data { payload: Vec<u8>, flags: u32 },
+    Close,
+}
+
 pub(crate) async fn handle_via_middle_proxy<R, W>(
     mut crypto_reader: CryptoReader<R>,
     crypto_writer: CryptoWriter<W>,
@@ -59,6 +64,30 @@ where
 
     let frame_limit = config.general.max_client_frame;
 
+    let (c2me_tx, mut c2me_rx) = mpsc::channel::<C2MeCommand>(1024);
+    let me_pool_c2me = me_pool.clone();
+    let c2me_sender = tokio::spawn(async move {
+        while let Some(cmd) = c2me_rx.recv().await {
+            match cmd {
+                C2MeCommand::Data { payload, flags } => {
+                    me_pool_c2me.send_proxy_req(
+                        conn_id,
+                        success.dc_idx,
+                        peer,
+                        translated_local_addr,
+                        &payload,
+                        flags,
+                    ).await?;
+                }
+                C2MeCommand::Close => {
+                    let _ = me_pool_c2me.send_close(conn_id).await;
+                    return Ok(());
+                }
+            }
+        }
+        Ok(())
+    });
+
     let (stop_tx, mut stop_rx) = oneshot::channel::<()>();
     let mut me_rx_task = me_rx;
     let stats_clone = stats.clone();
@@ -147,22 +176,20 @@ where
                 if payload.len() >= 8 && payload[..8].iter().all(|b| *b == 0) {
                     flags |= RPC_FLAG_NOT_ENCRYPTED;
                 }
-                if let Err(e) = me_pool.send_proxy_req(
-                    conn_id,
-                    success.dc_idx,
-                    peer,
-                    translated_local_addr,
-                    &payload,
-                    flags,
-                ).await {
-                    main_result = Err(e);
+                // Keep client read loop lightweight: route heavy ME send path via a dedicated task.
+                if c2me_tx
+                    .send(C2MeCommand::Data { payload, flags })
+                    .await
+                    .is_err()
+                {
+                    main_result = Err(ProxyError::Proxy("ME sender channel closed".into()));
                     break;
                 }
             }
             Ok(None) => {
                 debug!(conn_id, "Client EOF");
                 client_closed = true;
-                let _ = me_pool.send_close(conn_id).await;
+                let _ = c2me_tx.send(C2MeCommand::Close).await;
                 break;
             }
             Err(e) => {
@@ -172,6 +199,11 @@ where
         }
     }
 
+    drop(c2me_tx);
+    let c2me_result = c2me_sender
+        .await
+        .unwrap_or_else(|e| Err(ProxyError::Proxy(format!("ME sender join error: {e}"))));
+
     let _ = stop_tx.send(());
     let mut writer_result = me_writer
         .await
@@ -187,10 +219,11 @@ where
         }
     }
 
-    let result = match (main_result, writer_result) {
-        (Ok(()), Ok(())) => Ok(()),
-        (Err(e), _) => Err(e),
-        (_, Err(e)) => Err(e),
+    let result = match (main_result, c2me_result, writer_result) {
+        (Ok(()), Ok(()), Ok(())) => Ok(()),
+        (Err(e), _, _) => Err(e),
+        (_, Err(e), _) => Err(e),
+        (_, _, Err(e)) => Err(e),
     };
 
     debug!(user = %user, conn_id, "ME relay cleanup");