From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [RFC PATCH 0/2] Faster/parallel SYN handling to mitigate SYN floods Date: Thu, 31 May 2012 14:51:33 +0200 Message-ID: <1338468693.7747.162.camel@localhost> References: <20120528115102.12068.79994.stgit@localhost.localdomain> <4FC3A465.4030203@uclouvain.be> <1338322661.7747.17.camel@localhost> <4FC53353.2050801@uclouvain.be> <1338367497.7747.72.camel@localhost> <4FC5DFF4.1020604@uclouvain.be> <1338417630.7747.156.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Eric Dumazet , "David S. Miller" , Martin Topholm , Florian Westphal , Hans Schillstrom , Andi Kleen To: christoph.paasch@uclouvain.be Return-path: Received: from mx1.redhat.com ([209.132.183.28]:1030 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757516Ab2EaMwD (ORCPT ); Thu, 31 May 2012 08:52:03 -0400 In-Reply-To: <1338417630.7747.156.camel@localhost> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 2012-05-31 at 00:40 +0200, Jesper Dangaard Brouer wrote: > That seems like a very unlikely situation, which we perhaps should > neglect as we are under SYN attack. > > I will test the attack vector, if we instead of dropping the reqsk, > fall back into the slow locked path. I can provoke this attack vector, and performance is worse, if not dropping the reqsk early. Generator SYN flood at 750Kpps, sending false retransmits mixture. - With early drop: 406 Kpps - With return to locked processing: 251 Kpps Its still better than the approx 150Kpps, without any patches. -- Best regards, Jesper Dangaard Brouer MSc.CS, Sr. Network Kernel Developer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer