Subject: [PATCH] gre: Fix MTU calculation for bound GRE tunnels

From: Tom Goff <[email-masked]>
Date: Fri, 14 Aug 2009 11:37:58 -0700

The GRE header length should be subtracted when the tunnel MTU is
calculated.  This just corrects for the associativity change
introduced by commit 42aa916265d740d66ac1f17290366e9494c884c2.

Signed-off-by: Tom Goff <[email-masked]>
---
 net/ipv4/ip_gre.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index cb4a0f4..82c11dd 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -951,7 +951,7 @@ static int ipgre_tunnel_bind_dev(struct net_device *dev)
 			addend += 4;
 	}
 	dev->needed_headroom = addend + hlen;
-	mtu -= dev->hard_header_len - addend;
+	mtu -= dev->hard_header_len + addend;
 
 	if (mtu < 68)
 		mtu = 68;
-- 
1.6.0.6