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

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

[Ben Greear]

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>
---
:100644 100644 7f52603... 9fa308b... M	net/core/dev.c
 net/core/dev.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 7f52603..9fa308b 100644
--- 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;
 	}
-- 
1.6.2.5

Re: [PATCH] net/core: Allow tagged VLAN packets to flow through VETH devices.

[David Miller]

From: Ben Greear <greearb@candelatech.com>
Date: Fri, 15 Oct 2010 11:35:05 -0700

> 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>

Applied, although a check of the vlan-capable netdev flag
might be appropriate to add.