Re: [Qemu-devel] [PATCH V2 2/4] net/colo-compare.c: Compare the tcp packets that has the same sequence number

[Dr. David Alan Gilbert]

* Zhang Chen (address@hidden) wrote:
> If primary packet's sequence number not same with secondary packet's
> sequence number, no need to compare the packet other field.
> 
> Signed-off-by: Zhang Chen <address@hidden>
> ---
>  net/colo-compare.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/net/colo-compare.c b/net/colo-compare.c
> index 0f8e198..2caeb80 100644
> --- a/net/colo-compare.c
> +++ b/net/colo-compare.c
> @@ -222,6 +222,12 @@ static int colo_packet_compare_tcp(Packet *spkt, Packet 
> *ppkt)
>      ptcp = (struct tcphdr *)ppkt->transport_header;
>      stcp = (struct tcphdr *)spkt->transport_header;
>  
> +    if ((ptcp->th_flags & TH_SYN) != TH_SYN &&
> +        ptcp->th_seq != stcp->th_seq) {
> +        trace_colo_compare_main("colo_packet_compare_tcp seq not same");
> +        return -1;
> +    }

Do you need to check that the stcp->th_flags is the same ?

Looking back at patches I had in this area; I was doing
  if (ptcp->th_flags == stcp->th_flags &&

see:
   
https://github.com/orbitfp7/qemu/commit/848ca1113aec802dd032fd5b6d6b301931b3e1e0

Dave

>      /*
>       * The 'identification' field in the IP header is *very* random
>       * it almost never matches.  Fudge this by ignoring differences in
> -- 
> 2.7.4
> 
> 
> 
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK