From: Eric Dumazet <edumazet@google.com>
Date: Tue, 5 Feb 2013 20:22:20 +0000 (+0000)
Subject: net: reset mac header in dev_start_xmit()
X-Git-Tag: next-20130218~68^2~93
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6d1ccff62780;p=karo-tx-linux.git

net: reset mac header in dev_start_xmit()

On 64 bit arches :

There is a off-by-one error in qdisc_pkt_len_init() because
mac_header is not set in xmit path.

skb_mac_header() returns an out of bound value that was
harmless because hdr_len is an 'unsigned int'

On 32bit arches, the error is abysmal.

This patch is also a prereq for "macvlan: add multicast filter"

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/core/dev.c b/net/core/dev.c
index 65da698c500b..2f31bf97ba65 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2835,6 +2835,8 @@ int dev_queue_xmit(struct sk_buff *skb)
 	struct Qdisc *q;
 	int rc = -ENOMEM;
 
+	skb_reset_mac_header(skb);
+
 	/* Disable soft irqs for various locks below. Also
 	 * stops preemption for RCU.
 	 */