From: "Yan, Zheng" <zheng.z.yan@intel.com>
To: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"eric.dumazet@gmail.com" <eric.dumazet@gmail.com>,
herbert@gondor.apana.org.au, "sfr@c
Subject: [BUG?] tcp: potential bug in tcp_is_sackblock_valid()
Date: Fri, 09 Sep 2011 09:45:52 +0800 [thread overview]
Message-ID: <4E696FD0.7060702@intel.com> (raw)
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.
Regards
Yan, Zheng
next reply other threads:[~2011-09-09 1:45 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-09 1:45 Yan, Zheng [this message]
2011-09-09 1:54 ` [BUG?] tcp: potential bug in tcp_is_sackblock_valid() Herbert Xu
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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