From c91f1d05c65526fe250cf5e5c32f9038721bc1d5 Mon Sep 17 00:00:00 2001
From: yangchen <yangchen145@huawei.com>
Date: Mon, 25 Dec 2023 12:39:56 +0800
Subject: [PATCH] tcp_send_fin: add the fin to the last unsent segment

---
 src/core/tcp_out.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/core/tcp_out.c b/src/core/tcp_out.c
index 137e3cf..e5c407e 100644
--- a/src/core/tcp_out.c
+++ b/src/core/tcp_out.c
@@ -1195,8 +1195,8 @@ tcp_send_fin(struct tcp_pcb *pcb)
   LWIP_ASSERT("tcp_send_fin: invalid pcb", pcb != NULL);
 
   /* first, try to add the fin to the last unsent segment */
-  if (pcb->unsent != NULL) {
-    struct tcp_seg *last_unsent = pcb->unsent;
+  if (pcb->last_unsent != NULL) {
+    struct tcp_seg *last_unsent = pcb->last_unsent;
 
     if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN | TCP_FIN | TCP_RST)) == 0) {
       /* no SYN/FIN/RST flag in the header, we can add the FIN flag */
-- 
2.33.0