FW: PROBLEM: VLAN LRO issue

FW: PROBLEM: VLAN LRO issue

[Steven Liu (劉人豪)]

Hi Sir,

I found the issue about VLAN LRO feature and below is bug description and patch for your reference, thanks.

[1.] One line summary of the problem: 
VLAN LRO issue

[2.] Full description of the problem/report:
LRO implementation cannot handle VLAN tagged packets correctly.
It uses correct packet length when creating new LRO session, but uses wrong packet length when putting following packets into exist LRO session.

[3.] Keywords (i.e., modules, networking, kernel):
Networking

[4.] Kernel version (from /proc/version):
Linux-3.4-rc3 and below

[5.] Output of Oops.. message (if applicable) with symbolic information
     resolved (see Documentation/oops-tracing.txt) System is still working, but cannot speed up VLAN tagged traffic.

[X.] Other notes, patches, fixes, workarounds:
We have to apply below patch to fix this issue.

--- linux-3.4-rc3/net/ipv4/inet_lro.orig        2012-05-08 20:09:44.810366089 +0800
+++ linux-3.4-rc3/net/ipv4/inet_lro.c   2012-05-08 20:09:33.331679419 +0800
@@ -353,7 +353,7 @@ static int __lro_proc_skb(struct net_lro
        if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
                goto out2;

-       if (lro_tcp_ip_check(iph, tcph, skb->len, lro_desc))
+       if (lro_tcp_ip_check(iph, tcph, skb->len - vlan_hdr_len, lro_desc))
                goto out2;

        lro_add_packet(lro_desc, skb, iph, tcph);



Regards,

Steven


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Re: FW: PROBLEM: VLAN LRO issue

[Eric Dumazet]

On Thu, 2012-05-10 at 09:01 +0800, Steven Liu (劉人豪) wrote:
> Hi Sir,
> 
> I found the issue about VLAN LRO feature and below is bug description and patch for your reference, thanks.
> 
> [1.] One line summary of the problem: 
> VLAN LRO issue
> 
> [2.] Full description of the problem/report:
> LRO implementation cannot handle VLAN tagged packets correctly.
> It uses correct packet length when creating new LRO session, but uses wrong packet length when putting following packets into exist LRO session.
> 
> [3.] Keywords (i.e., modules, networking, kernel):
> Networking
> 
> [4.] Kernel version (from /proc/version):
> Linux-3.4-rc3 and below
> 
> [5.] Output of Oops.. message (if applicable) with symbolic information
>      resolved (see Documentation/oops-tracing.txt) System is still working, but cannot speed up VLAN tagged traffic.
> 
> [X.] Other notes, patches, fixes, workarounds:
> We have to apply below patch to fix this issue.
> 
> --- linux-3.4-rc3/net/ipv4/inet_lro.orig        2012-05-08 20:09:44.810366089 +0800
> +++ linux-3.4-rc3/net/ipv4/inet_lro.c   2012-05-08 20:09:33.331679419 +0800
> @@ -353,7 +353,7 @@ static int __lro_proc_skb(struct net_lro
>         if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
>                 goto out2;
> 
> -       if (lro_tcp_ip_check(iph, tcph, skb->len, lro_desc))
> +       if (lro_tcp_ip_check(iph, tcph, skb->len - vlan_hdr_len, lro_desc))
>                 goto out2;
> 
>         lro_add_packet(lro_desc, skb, iph, tcph);
> 

Hi 

This looks like a good fix, could you please submit an official patch ?

Documentation/SubmittingPatches