net/core: Allow tagged VLAN packets to flow through VETH devices.

When there are VLANs on a VETH device, the packets being transmitted
through the VETH device may be 4 bytes bigger than MTU.  A check
in dev_forward_skb did not take this into account and so dropped
these packets.

This patch is needed at least as far back as 2.6.34.7 and should
be considered for -stable.

Signed-off-by: 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 660dd41aaaa6629c0d59547e04d23353ba935af8..8e07109cc0ef30828406b3b6bab6ed2bc9d62125 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1485,7 +1485,7 @@ int dev_forward_skb(struct net_device *dev, struct sk_buff *skb)
        nf_reset(skb);
 
        if (!(dev->flags & IFF_UP) ||
-           (skb->len > (dev->mtu + dev->hard_header_len))) {
+           (skb->len > (dev->mtu + dev->hard_header_len + VLAN_HLEN))) {
                kfree_skb(skb);
                return NET_RX_DROP;
        }