[net-2.6] net: bug fix for vlan + gro issue

On 16/02/10 19:40 +0800, Herbert Xu wrote:
> On Fri, Feb 12, 2010 at 11:04:53AM +0530, Ajit Khaparde wrote:
> >
> > diff --git a/net/core/dev.c b/net/core/dev.c
> > index be9924f..16aac06 100644
> > --- a/net/core/dev.c
> > +++ b/net/core/dev.c
> > @@ -2761,7 +2761,10 @@ gro_result_t napi_frags_finish(struct napi_struct *napi, struct sk_buff *skb,
> >  	switch (ret) {
> >  	case GRO_NORMAL:
> >  	case GRO_HELD:
> > -		skb->protocol = eth_type_trans(skb, napi->dev);
> > +		if (skb->vlan_tci)
> > +			skb->protocol = eth_type_trans(skb, skb->dev);
> > +		else
> > +			skb->protocol = eth_type_trans(skb, napi->dev);
> 
> We should be able to just use skb->dev here.

Thanks Herbert. I think you meant something like this:
+		skb->protocol = eth_type_trans(skb, skb->dev);

Here is the patch:-

Traffic (tcp) doesnot start on a vlan interface when gro is enabled.
Even the tcp handshake was not taking place.
This is because, the eth_type_trans call before the netif_receive_skb
in napi_gro_finish() resets the skb->dev to napi->dev from the previously
set vlan netdev interface. This causes the ip_route_input to drop the
incoming packet considering it as a packet coming from a martian source.

I could repro this on 2.6.32.7 (stable) and 2.6.33-rc7.
With this fix, the traffic starts and the test runs fine on both vlan
and non-vlan interfaces.

CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: Ajit Khaparde <ajitk@serverengines.com>
---
 net/core/dev.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

On Wed, Feb 17, 2010 at 11:55:43AM +0530, Ajit Khaparde wrote:
>
> Here is the patch:-
> 
> Traffic (tcp) doesnot start on a vlan interface when gro is enabled.
> Even the tcp handshake was not taking place.
> This is because, the eth_type_trans call before the netif_receive_skb
> in napi_gro_finish() resets the skb->dev to napi->dev from the previously
> set vlan netdev interface. This causes the ip_route_input to drop the
> incoming packet considering it as a packet coming from a martian source.
> 
> I could repro this on 2.6.32.7 (stable) and 2.6.33-rc7.
> With this fix, the traffic starts and the test runs fine on both vlan
> and non-vlan interfaces.
> 
> CC: Herbert Xu <herbert@gondor.apana.org.au>
> CC: Patrick McHardy <kaber@trash.net>
> Signed-off-by: Ajit Khaparde <ajitk@serverengines.com>

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Thanks a lot!

From: Ajit Khaparde <ajitkhaparde@gmail.com>
Date: Wed, 17 Feb 2010 11:55:43 +0530

> Thanks Herbert. I think you meant something like this:
> +		skb->protocol = eth_type_trans(skb, skb->dev);
> 
> Here is the patch:-
> 
> Traffic (tcp) doesnot start on a vlan interface when gro is enabled.
> Even the tcp handshake was not taking place.
> This is because, the eth_type_trans call before the netif_receive_skb
> in napi_gro_finish() resets the skb->dev to napi->dev from the previously
> set vlan netdev interface. This causes the ip_route_input to drop the
> incoming packet considering it as a packet coming from a martian source.
> 
> I could repro this on 2.6.32.7 (stable) and 2.6.33-rc7.
> With this fix, the traffic starts and the test runs fine on both vlan
> and non-vlan interfaces.
> 
> CC: Herbert Xu <herbert@gondor.apana.org.au>
> CC: Patrick McHardy <kaber@trash.net>
> Signed-off-by: Ajit Khaparde <ajitk@serverengines.com>

Applied, thanks.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html