From 81f9442ac7ff44327e6c663cdf301e277e34bea3 Mon Sep 17 00:00:00 2001
From: goldsimon <goldsimon>
Date: Fri, 23 Oct 2009 13:17:18 +0000
Subject: [PATCH] Fixed bug #27783: Silly window avoidance for small window
 sizes

---
 CHANGELOG      | 3 +++
 src/core/tcp.c | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG b/CHANGELOG
index b2a12a43..0c2a6a19 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -43,6 +43,9 @@ HISTORY
 
   ++ Bugfixes:
 
+  2009-10-23: Simon Goldschmidt (David Empson)
+  * tcp.c: Fixed bug #27783: Silly window avoidance for small window sizes
+
   2009-10-22: Simon Goldschmidt
   * tcp_in.c: Fixed bug #26251: RST process in TIME_WAIT TCP state
 
diff --git a/src/core/tcp.c b/src/core/tcp.c
index 57b2a1a9..fffbe555 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -408,7 +408,7 @@ u32_t tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb)
 {
   u32_t new_right_edge = pcb->rcv_nxt + pcb->rcv_wnd;
 
-  if (TCP_SEQ_GEQ(new_right_edge, pcb->rcv_ann_right_edge + pcb->mss)) {
+  if (TCP_SEQ_GEQ(new_right_edge, pcb->rcv_ann_right_edge + LWIP_MIN((TCP_WND / 2), pcb->mss))) {
     /* we can advertise more window */
     pcb->rcv_ann_wnd = pcb->rcv_wnd;
     return new_right_edge - pcb->rcv_ann_right_edge;