From: Eric Dumazet <eric.dumazet@gmail.com>
To: Dave Taht <dave.taht@gmail.com>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>,
netdev <netdev@vger.kernel.org>,
Neal Cardwell <ncardwell@google.com>,
Tom Herbert <therbert@google.com>,
Jesper Dangaard Brouer <brouer@redhat.com>
Subject: Re: [PATCH net-next] tcp: avoid tx starvation by SYNACK packets
Date: Sat, 02 Jun 2012 07:46:32 +0200 [thread overview]
Message-ID: <1338615992.2760.1665.camel@edumazet-glaptop> (raw)
In-Reply-To: <CAA93jw755V9kJ=P1gFsG2oafddhsebzfT3DuY5NX59GPpheOZg@mail.gmail.com>
On Fri, 2012-06-01 at 18:28 -0700, Dave Taht wrote:
> On Thu, May 31, 2012 at 2:56 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> > From: Eric Dumazet <edumazet@google.com>
> >
> > pfifo_fast being the default Qdisc, its pretty easy to fill it with
> > SYNACK (small) packets while host is under SYNFLOOD attack.
> >
> > Packets of established TCP sessions are dropped and host appears almost
> > dead.
> >
> > Avoid this problem assigning TC_PRIO_FILLER priority to SYNACK
> > generated in SYNCOOKIE mode, so that these packets are enqueued into
> > pfifo_fast band 2.
> >
> > Other packets, queued to band 0 or 1 are dequeued before any SYNACK
> > packets waiting in band 2.
>
> I am curious as to how well fq_codel survives an attack like this, without aid.
codel or fq_codel are not doing priority classification.
SYNACK will spread in all hash buckets and global queue limit can be
hit.
fq_codel wont protect you by itself, unless you use a hierarchy with one
"prio" and two or three "fq_codel".
next prev parent reply other threads:[~2012-06-02 5:46 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-31 21:56 [PATCH net-next] tcp: avoid tx starvation by SYNACK packets Eric Dumazet
2012-05-31 23:03 ` David Miller
2012-06-01 4:48 ` Eric Dumazet
2012-06-01 17:46 ` David Miller
2012-06-01 7:00 ` [PATCH] tcp: do not create inetpeer on SYNACK message Eric Dumazet
2012-06-01 18:24 ` David Miller
2012-06-01 21:34 ` Hans Schillström
2012-06-02 6:56 ` Eric Dumazet
2012-06-01 7:36 ` [PATCH net-next] tcp: avoid tx starvation by SYNACK packets Hans Schillstrom
2012-06-01 9:34 ` Eric Dumazet
2012-06-02 1:28 ` Dave Taht
2012-06-02 5:46 ` Eric Dumazet [this message]
2012-06-23 7:34 ` Vijay Subramanian
2012-06-23 8:42 ` [PATCH v2 " Eric Dumazet
2012-06-25 6:24 ` Hans Schillstrom
2012-06-25 22:43 ` David Miller
2012-06-26 4:51 ` Eric Dumazet
2012-06-26 4:55 ` David Miller
2012-06-26 5:34 ` Hans Schillstrom
2012-06-26 7:11 ` David Miller
2012-06-26 7:27 ` Hans Schillstrom
2012-06-26 17:02 ` Eric Dumazet
2012-06-27 5:23 ` Hans Schillstrom
2012-06-27 8:22 ` David Miller
2012-06-27 8:25 ` Jesper Dangaard Brouer
2012-06-27 8:30 ` Hans Schillstrom
2012-06-27 8:40 ` Eric Dumazet
2012-06-27 8:48 ` David Miller
2012-06-27 6:32 ` Jesper Dangaard Brouer
2012-06-27 6:54 ` David Miller
2012-06-27 7:24 ` Jesper Dangaard Brouer
2012-06-27 7:30 ` Eric Dumazet
2012-06-27 7:54 ` Jesper Dangaard Brouer
2012-06-27 8:02 ` Eric Dumazet
2012-06-27 8:21 ` Jesper Dangaard Brouer
2012-06-27 8:45 ` Eric Dumazet
2012-06-27 9:23 ` Jesper Dangaard Brouer
2012-06-27 8:13 ` David Miller
2012-06-27 19:50 ` Florian Westphal
2012-06-27 21:39 ` Eric Dumazet
2012-06-27 22:23 ` David Miller
2012-06-27 22:23 ` David Miller
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