[PATCH net-next] gre: Set inner mac header in gro complete

[PATCH net-next] gre: Set inner mac header in gro complete

[Tom Herbert]

Set the inner mac header to point to the GRE payload when
doing GRO. This is needed if we proceed to send the packet
through GRE GSO which now uses the inner mac header instead
of inner network header to determine the length of encapsulation
headers.

Reported-by: Wolfgang Walter <linux@stwm.de>
Signed-off-by: Tom Herbert <therbert@google.com>
---
 net/ipv4/gre_offload.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index bb5947b..51973dd 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -247,6 +247,9 @@ static int gre_gro_complete(struct sk_buff *skb, int nhoff)
 		err = ptype->callbacks.gro_complete(skb, nhoff + grehlen);
 
 	rcu_read_unlock();
+
+	skb_set_inner_mac_header(skb, nhoff + grehlen);
+
 	return err;
 }
 
-- 
2.1.0.rc2.206.gedb03e5

Re: [PATCH net-next] gre: Set inner mac header in gro complete

[Eric Dumazet]

On Tue, 2014-11-25 at 09:30 -0800, Tom Herbert wrote:
> Set the inner mac header to point to the GRE payload when
> doing GRO. This is needed if we proceed to send the packet
> through GRE GSO which now uses the inner mac header instead
> of inner network header to determine the length of encapsulation
> headers.
> 
> Reported-by: Wolfgang Walter <linux@stwm.de>
> Signed-off-by: Tom Herbert <therbert@google.com>
> ---

Please Tom, add in your bug fixes something to ease backports.

Fixes: 14051f0452a2 ("gre: Use inner mac length when computing tunnel length")

Re: [PATCH net-next] gre: Set inner mac header in gro complete

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 25 Nov 2014 09:57:21 -0800

> On Tue, 2014-11-25 at 09:30 -0800, Tom Herbert wrote:
>> Set the inner mac header to point to the GRE payload when
>> doing GRO. This is needed if we proceed to send the packet
>> through GRE GSO which now uses the inner mac header instead
>> of inner network header to determine the length of encapsulation
>> headers.
>> 
>> Reported-by: Wolfgang Walter <linux@stwm.de>
>> Signed-off-by: Tom Herbert <therbert@google.com>
>> ---
> 
> Please Tom, add in your bug fixes something to ease backports.
> 
> Fixes: 14051f0452a2 ("gre: Use inner mac length when computing tunnel length")

Also this is extremely far reaching consequences.

The bug is in Linus's tree, so net-next is not a suitable target,
'net' is.

Also, the commit in question has been backported into -stable, so
I would need to queue it up there as well.

Please respin this against 'net', and add the Fixes: tag, thanks.