On 11/30/2017 9:57 AM, Eric Dumazet wrote:
> On Thu, 2017-11-30 at 10:30 -0700, David Ahern wrote:
>> On 11/30/17 8:44 AM, David Ahern wrote:
>>> On 11/30/17 3:50 AM, Eric Dumazet wrote:
>>>> @@ -1631,24 +1659,6 @@ int tcp_v4_rcv(struct sk_buff *skb)
>>>>
>>>> th = (const struct tcphdr *)skb->data;
>>>> iph = ip_hdr(skb);
>>>> - /* This is tricky : We move IPCB at its correct location
>>>> into TCP_SKB_CB()
>>>> - * barrier() makes sure compiler wont play
>>>> fool^Waliasing games.
>>>> - */
>>>> - memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
>>>> - sizeof(struct inet_skb_parm));
>>>> - barrier();
>>>> -
>>>> - TCP_SKB_CB(skb)->seq = ntohl(th->seq);
>>>> - TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th-
>>>>> syn + th->fin +
>>>> - skb->len - th->doff * 4);
>>>> - TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
>>>> - TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
>>>> - TCP_SKB_CB(skb)->tcp_tw_isn = 0;
>>>> - TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
>>>> - TCP_SKB_CB(skb)->sacked = 0;
>>>> - TCP_SKB_CB(skb)->has_rxtstamp =
>>>> - skb->tstamp || skb_hwtstamps(skb)-
>>>>> hwtstamp;
>>>> -
>>>> lookup:
>>>> sk = __inet_lookup_skb(&tcp_hashinfo, skb,
>>>> __tcp_hdrlen(th), th->source,
>>>> th->dest, sdif, &refcounted);
>>> I believe moving the above is going to affect lookups with VRF. Let
>>> me
>>> take a look before this gets committed.
>>>
>> Eric:
>>
>> Can you add this to the patch? Fixes socket lookups with VRF which
>> stashes a flag in the cb.
I've done my testing and it works both ways for Smack.
>>
>> Thanks,
>>
>> diff --git a/include/net/tcp.h b/include/net/tcp.h
>> index 4e09398009c1..6c020015d556 100644
>> --- a/include/net/tcp.h
>> +++ b/include/net/tcp.h
>> @@ -849,7 +849,7 @@ static inline bool inet_exact_dif_match(struct
>> net
>> *net, struct sk_buff *skb)
>> {
>> #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
>> if (!net->ipv4.sysctl_tcp_l3mdev_accept &&
>> - skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags))
>> + skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
>> return true;
>> #endif
>> return false;
>
> I wonder if this should not be in a separate patch ?
>
> Bug was added in 971f10eca186cab238c49daa91f703c5a001b0b1 ("tcp: better
> TCP_SKB_CB layout to reduce cache line misses") in linux 3.18
>
> While VRF was added later.
>
> If you agree, I will prepare a patch series, with different Fixes tag
> so that David can decide which path needs to be backported into each
> stable version.
>
> Thanks.
>
>
