From 805eed84473ababca496054d7ebb9ba65e931992 Mon Sep 17 00:00:00 2001
From: XOR-op <17672363+XOR-op@users.noreply.github.com>
Date: Sat, 21 Sep 2024 23:31:27 -0400
Subject: [PATCH 1/2] fix: internal sACK flag not updated for client socket

---
 src/socket/tcp.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/socket/tcp.rs b/src/socket/tcp.rs
index f944875ad..988bce905 100644
--- a/src/socket/tcp.rs
+++ b/src/socket/tcp.rs
@@ -1806,6 +1806,7 @@ impl<'a> Socket<'a> {
                 self.remote_seq_no = repr.seq_number + 1;
                 self.remote_last_seq = self.local_seq_no + 1;
                 self.remote_last_ack = Some(repr.seq_number);
+                self.remote_has_sack = repr.sack_permitted;
                 self.remote_win_scale = repr.window_scale;
                 // Remote doesn't support window scaling, don't do it.
                 if self.remote_win_scale.is_none() {

From ffcb62e11923a7b51460ff6a0b3ced6c4d7fe14e Mon Sep 17 00:00:00 2001
From: XOR-op <17672363+XOR-op@users.noreply.github.com>
Date: Sun, 22 Sep 2024 17:50:38 -0400
Subject: [PATCH 2/2] test(tcp): add coverage for remote_has_sack in SYN-SENT
 state

---
 src/socket/tcp.rs | 57 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/src/socket/tcp.rs b/src/socket/tcp.rs
index 988bce905..46f1b36f9 100644
--- a/src/socket/tcp.rs
+++ b/src/socket/tcp.rs
@@ -3725,6 +3725,63 @@ mod test {
         assert_eq!(s.state, State::Closed);
     }
 
+    #[test]
+    fn test_syn_sent_sack_option() {
+        let mut s = socket_syn_sent();
+        recv!(
+            s,
+            [TcpRepr {
+                control: TcpControl::Syn,
+                seq_number: LOCAL_SEQ,
+                ack_number: None,
+                max_seg_size: Some(BASE_MSS),
+                window_scale: Some(0),
+                sack_permitted: true,
+                ..RECV_TEMPL
+            }]
+        );
+        send!(
+            s,
+            TcpRepr {
+                control: TcpControl::Syn,
+                seq_number: REMOTE_SEQ,
+                ack_number: Some(LOCAL_SEQ + 1),
+                max_seg_size: Some(BASE_MSS - 80),
+                window_scale: Some(0),
+                sack_permitted: true,
+                ..SEND_TEMPL
+            }
+        );
+        assert!(s.remote_has_sack);
+
+        let mut s = socket_syn_sent();
+        recv!(
+            s,
+            [TcpRepr {
+                control: TcpControl::Syn,
+                seq_number: LOCAL_SEQ,
+                ack_number: None,
+                max_seg_size: Some(BASE_MSS),
+                window_scale: Some(0),
+                sack_permitted: true,
+                ..RECV_TEMPL
+            }]
+        );
+        send!(
+            s,
+            TcpRepr {
+                control: TcpControl::Syn,
+                seq_number: REMOTE_SEQ,
+                ack_number: Some(LOCAL_SEQ + 1),
+                max_seg_size: Some(BASE_MSS - 80),
+                window_scale: Some(0),
+                sack_permitted: false,
+                ..SEND_TEMPL
+            }
+        );
+        assert!(!s.remote_has_sack);
+    }
+
     #[test]
     fn test_syn_sent_win_scale_buffers() {
         for (buffer_size, shift_amt) in &[