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From: Herbert Xu <herbert@gondor.apana.org.au>
To: "Yan, Zheng" <zheng.z.yan@intel.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"eric.dumazet@gmail.com" <eric.dumazet@gmail.com>,
	"sfr@canb.auug.org.au" <sfr@canb.auug.org.au>
Subject: Re: [BUG?] tcp: potential bug in tcp_is_sackblock_valid()
Date: Fri, 9 Sep 2011 11:54:29 +1000	[thread overview]
Message-ID: <20110909015429.GA9156@gondor.apana.org.au> (raw)
In-Reply-To: <4E696FD0.7060702@intel.com>

On Fri, Sep 09, 2011 at 09:45:52AM +0800, Yan, Zheng wrote:
> Hi all,
> 
> I found a check in tcp_is_sackblock_valid() is suspicious. It against
> its comment and RFC. I think the correct check should be:
> 
> ---
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 385c470..a5d01b1 100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -1124,7 +1124,7 @@ static int tcp_is_sackblock_valid(struct tcp_sock *tp, int is_dsack,
>                 return 0;
>  
>         /* ...Then it's D-SACK, and must reside below snd_una completely */
> -       if (!after(end_seq, tp->snd_una))
> +       if (after(end_seq, tp->snd_una))
>                 return 0;
>  
>         if (!before(start_seq, tp->undo_marker))
> ---
> 
> I also checked /proc/net/netstat of my laptop, found TCPDSACKIgnoredOld
> field is not zero. Maybe it's caused by the bug.

Yes this looks like a typo.  Please resend your patch with a
description and signed-off-by line.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

  reply	other threads:[~2011-09-09  1:54 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-09  1:45 [BUG?] tcp: potential bug in tcp_is_sackblock_valid() Yan, Zheng
2011-09-09  1:54 ` Herbert Xu [this message]
2011-09-09  2:10   ` Yan, Zheng
2011-09-09  8:03     ` Ilpo Järvinen
     [not found]       ` <CAA93jw7L9KyXVevZ8dqE+ExLYP9=CLMmj1gPD88ihBuC6ZovOQ@mail.gmail.com>
2011-09-18 20:39         ` Eric Dumazet
2011-09-18 21:04           ` Dave Taht
2011-09-18 21:20             ` Hagen Paul Pfeifer
2011-09-18 19:35 ` Eric Dumazet
2011-09-19  1:07   ` David Miller
2011-09-19  2:05     ` [PATCH] tcp: fix validation of D-SACK Yan, Zheng
2011-09-19  2:37       ` David Miller
2011-09-19 17:29         ` Jan Ceuleers
2011-09-20 18:50           ` David Miller

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