From: Rick Jones <rick.jones2@hpe.com>
To: Eric Dumazet <eric.dumazet@gmail.com>, Peter Wu <peter@lekensteyn.nl>
Cc: "David S . Miller" <davem@davemloft.net>,
netdev@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
Kui Zhang <kuizhang@gmail.com>
Subject: Re: [PATCH] tcp: ensure non-empty connection request queue
Date: Wed, 4 May 2016 10:24:24 -0700 [thread overview]
Message-ID: <572A3048.60802@hpe.com> (raw)
In-Reply-To: <1462321544.5535.337.camel@edumazet-glaptop3.roam.corp.google.com>
On 05/03/2016 05:25 PM, Eric Dumazet wrote:
> On Tue, 2016-05-03 at 23:54 +0200, Peter Wu wrote:
>> When applications use listen() with a backlog of 0, the kernel would
>> set the maximum connection request queue to zero. This causes false
>> reports of SYN flooding (if tcp_syncookies is enabled) or packet drops
>> otherwise.
>>
> Well, I believe I already gave my opinion on this.
>
> listen backlog is not a hint. This is a limit.
>
> It is the limit of outstanding children in accept queue.
>
> If backlog is 0, no child can be put in the accept queue.
>
> It is therefore Working As Intented.
Dropping the connection attempt makes sense, but is entering/claiming
synflood really indicated in the case of a zero-length accept queue?
rick
next prev parent reply other threads:[~2016-05-04 17:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-03 21:54 [PATCH] tcp: ensure non-empty connection request queue Peter Wu
2016-05-04 0:25 ` Eric Dumazet
2016-05-04 9:40 ` Peter Wu
2016-05-04 17:24 ` Rick Jones [this message]
2016-05-04 17:34 ` Eric Dumazet
2016-05-04 18:05 ` Rick Jones
2016-05-04 18:18 ` Eric Dumazet
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