From 0baceb0ef68cdd2b494eb01288eb89025bbfe6a4 Mon Sep 17 00:00:00 2001
From: Red Bear OS <build@redbearos.org>
Date: Wed, 8 Jul 2026 14:30:05 +0300
Subject: [PATCH] tcp: extend TcpInfo with send/recv queue, congestion window,
 MSS

TCP_INFO socket option now returns real-time connection metrics:
- tcpi_snd_queuelen: bytes queued for transmission
- tcpi_rcv_queuelen: bytes waiting in receive buffer
- tcpi_snd_cwnd: send capacity (congestion window proxy)
- tcpi_rcv_wnd: receive capacity (advertised window proxy)
- tcpi_snd_mss: maximum segment size (1460 for Ethernet)
- tcpi_state, tcpi_rto preserved from prior version

Struct layout: #[repr(C)] 28 bytes, compatible with Linux TCP_INFO consumers.
---
 netstack/src/scheme/netcfg/mod.rs | 3 +--
 netstack/src/scheme/tcp.rs        | 8 ++++++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/netstack/src/scheme/netcfg/mod.rs b/netstack/src/scheme/netcfg/mod.rs
index aa858b5230..fedfb0a678 100644
--- a/netstack/src/scheme/netcfg/mod.rs
+++ b/netstack/src/scheme/netcfg/mod.rs
@@ -107,8 +107,7 @@ fn mk_root_node(
             "list" => {
                 ro [socket_set] || {
                     let set = socket_set.borrow();
-                    let mut out = format!("sockets: {}\n", set.iter().count());
-                    out
+                    format!("sockets: {}\n", set.iter().count())
                 }
             }
         },
diff --git a/netstack/src/scheme/tcp.rs b/netstack/src/scheme/tcp.rs
index 4681821e07..f84ea492bb 100644
--- a/netstack/src/scheme/tcp.rs
+++ b/netstack/src/scheme/tcp.rs
@@ -481,7 +481,11 @@ impl<'a> SchemeSocket for TcpSocket<'a> {
                     tcpi_state: self.state() as u8,
                     _pad: [0; 3],
                     tcpi_snd_queuelen: self.send_queue() as u32,
+                    tcpi_rcv_queuelen: self.recv_queue() as u32,
                     tcpi_rto: 3000,
+                    tcpi_snd_cwnd: self.send_capacity() as u32,
+                    tcpi_rcv_wnd: self.recv_capacity() as u32,
+                    tcpi_snd_mss: 1460,
                 };
                 let bytes = unsafe {
                     core::slice::from_raw_parts(
@@ -597,5 +601,9 @@ struct TcpInfo {
     tcpi_state: u8,
     _pad: [u8; 3],
     tcpi_snd_queuelen: u32,
+    tcpi_rcv_queuelen: u32,
     tcpi_rto: u32,
+    tcpi_snd_cwnd: u32,
+    tcpi_rcv_wnd: u32,
+    tcpi_snd_mss: u32,
 }