From 593f75fc3bc02cdd0a08e2b02d15e014c250c9e2 Mon Sep 17 00:00:00 2001
From: goldsimon <goldsimon@gmx.de>
Date: Sat, 21 Jan 2012 18:05:15 +0100
Subject: [PATCH] fixed bug #34636: FIN_WAIT_2 - Incorrect shutdown of TCP pcb:
 don't let PCBs time out from FIN_WAIT_2 if the RX side wasn't close (by
 either calling tcp_close or tcp_shutdown(RDWR))

---
 CHANGELOG      |  3 +++
 src/core/tcp.c | 13 +++++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 63a8aa6b..89778164 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -62,6 +62,9 @@ HISTORY
 
  ++ Bugfixes:
 
+  2012-01-21: Simon Goldschmidt
+  * tcp.c: fixed bug #34636: FIN_WAIT_2 - Incorrect shutdown of TCP pcb
+
   2012-01-20: Simon Goldschmidt
   * dhcp.c: fixed bug #35151: DHCP asserts on incoming option lengths
 
diff --git a/src/core/tcp.c b/src/core/tcp.c
index 5c9796ee..4a5f0578 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -872,10 +872,15 @@ tcp_slowtmr_start:
     }
     /* Check if this PCB has stayed too long in FIN-WAIT-2 */
     if (pcb->state == FIN_WAIT_2) {
-      if ((u32_t)(tcp_ticks - pcb->tmr) >
-          TCP_FIN_WAIT_TIMEOUT / TCP_SLOW_INTERVAL) {
-        ++pcb_remove;
-        LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n"));
+      /* If this PCB is in FIN_WAIT_2 because of SHUT_WR don't let it time out. */
+      if (pcb->flags & TF_RXCLOSED) {
+        /* PCB was fully closed (either through close() or SHUT_RDWR):
+           normal FIN-WAIT timeout handling. */
+        if ((u32_t)(tcp_ticks - pcb->tmr) >
+            TCP_FIN_WAIT_TIMEOUT / TCP_SLOW_INTERVAL) {
+          ++pcb_remove;
+          LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n"));
+        }
       }
     }