From 2b1c38995584f7c68a0123bd2eddb5eb9e161293 Mon Sep 17 00:00:00 2001
From: goldsimon <goldsimon>
Date: Mon, 1 Mar 2010 18:43:37 +0000
Subject: [PATCH] Fixed accessing invalid memory when closing a listening pcb
 (introduced with tcp_shutdown)

---
 src/core/tcp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/core/tcp.c b/src/core/tcp.c
index ca0dfaf4..c8ac2ad3 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -233,8 +233,10 @@ tcp_close(struct tcp_pcb *pcb)
   tcp_debug_print_state(pcb->state);
 #endif /* TCP_DEBUG */
 
-  /* Set a flag not to receive any more data... */
-  pcb->flags |= TF_RXCLOSED;
+  if (pcb->state != LISTEN) {
+    /* Set a flag not to receive any more data... */
+    pcb->flags |= TF_RXCLOSED;
+  }
   /* ... and close */
   return tcp_close_shutdown(pcb, 1);
 }