From 75580c850b1b5ea71d0d613c50ad4e39d67be2ce Mon Sep 17 00:00:00 2001
From: kris <kris@e0a8ed71-7df4-0310-8962-fdc924857419>
Date: Mon, 2 Aug 2010 07:53:40 +0000
Subject: [PATCH] Don't fragment IP packets with DF set, even if o.fragscan is
 set.  If a packet is built to explicitly avoid fragmentation, honor it.

---
 tcpip.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tcpip.cc b/tcpip.cc
index ceba514be..2f56188df 100644
--- a/tcpip.cc
+++ b/tcpip.cc
@@ -571,7 +571,8 @@ int send_ip_packet(int sd, struct eth_nfo *eth, u8 *packet,
   assert((int) packetlen > 0);
 
   /* Fragmentation requested && packet is bigger than MTU */
-  if(o.fragscan && (packetlen - ip->ip_hl * 4 > (unsigned int) o.fragscan)){
+  if(o.fragscan && !(ntohs(ip->ip_off) & IP_DF) &&
+     (packetlen - ip->ip_hl * 4 > (unsigned int) o.fragscan)){
     res = send_frag_ip_packet(sd, eth, packet, packetlen, o.fragscan);
   }else{
     res = send_ip_packet_eth_or_sd(sd, eth, packet, packetlen);