From: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Date: Tue, 14 Dec 2010 12:35:13 +0000 (+0000)
Subject: net/veth: Fix packet checksumming
X-Git-Tag: v2.6.37-rc8~13^2~21
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0b7967503dc97864f283a3a06fbe23e041876138;p=users%2Fjedix%2Flinux-maple.git

net/veth: Fix packet checksumming

We can't change ip_summed from CHECKSUM_PARTIAL to CHECKSUM_NONE
or CHECKSUM_UNNECESSARY because checksum in packet's headers is
not valid and will cause invalid checksum when frame is forwarded.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 0bbc0c323135..cc83fa71c3ff 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -166,7 +166,9 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 	if (!(rcv->flags & IFF_UP))
 		goto tx_drop;
 
-	if (dev->features & NETIF_F_NO_CSUM)
+	/* don't change ip_summed == CHECKSUM_PARTIAL, as that
+	   will cause bad checksum on forwarded packets */
+	if (skb->ip_summed == CHECKSUM_NONE)
 		skb->ip_summed = rcv_priv->ip_summed;
 
 	length = skb->len + ETH_HLEN;