Date: Sat, 26 Jan 2008 22:27:31 +0100 From: Max Laier <max@love2party.net> To: freebsd-current@freebsd.org Cc: Stefan Lambrev <stefan.lambrev@moneybookers.com> Subject: Re: FreeBSD 7, bridge, PF and syn flood = very bad performance Message-ID: <200801262227.36970.max@love2party.net> In-Reply-To: <479B9F4F.5010705@moneybookers.com> References: <479A2389.2000802@moneybookers.com> <200801262017.52091.max@love2party.net> <479B9F4F.5010705@moneybookers.com>
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--nextPart1320325.ad8KbAYg12 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Saturday 26 January 2008, Stefan Lambrev wrote: > Max Laier wrote: > > On Friday 25 January 2008, Stefan Lambrev wrote: > >> Greetings, > >> > >> Does anyone try to see PF with "keep state" in action when under syn > >> flood attack? > >> I tried to get some help in freebsd-pf@, because the test firewall, > >> that I build hardly can handle 2-5MB/s syn flood. > >> Unfortunately I do not saw useful advice. > >> The problem is that a quad core bridge firewall running freebsd 7 > >> amd64 with PF is near useless and can't handle "small" SYN ddos. > >> > >> Here is the schema that I'm testing: > >> web server (freebsd) - freebsd (bridged interfaces) - gigabit switch > >> - clients + flooders > >> In this configuration ~25MB/s syn flood (and I think this limit is > >> because of my switch) is not a problem and the web server responds > >> without a problem. > >> With this configuration netperf -l 610 -p 10303 -H 10.3.3.1 shows > >> 116MB/s stable speed , so I guess there are no problems with cables, > >> hardware and etc :) > >> > >> But when I start pf (see below the config file) the traffic drops to > >> 2-3MB/s and the web server is hardly accessible. > >> It seems that device polling helps a lot in this situation, and at > >> least the bridge firewall is accessible. Without "polling" the > >> firewall is so heavily loaded > >> that even commands like "date" take few seconds to finish, with 2 > >> cores at ~100% idle at same time. > >> > >> I have "flat profiles" from hwpmc, and I think it indicates a > >> problem: > >> > >> (bridge, pf enabled, polling enabled, sched_ule - I have profiles > >> and for other combinations too if needed) > >> % cumulative self self total > >> time seconds seconds calls ms/call ms/call name > >> 24.0 268416.00 268416.00 0 100.00% =20 > >> _mtx_lock_sleep > > > > Can you build a kernel with LOCK_PROFILING and try to figure out > > which lock is causing this? > > Yes I can build kernel with LOCK_PROFILING. > But I have no idea how to use it :) > Can you point me to some documentation? man LOCK_PROFILING basically: # sysctl debug.lock.prof.enable=3D1 && sleep 60 && \ sysctl debug.lock.prof.enable=3D0 && \ sysctl debug.lock.prof.stats > log while under attack to sample one minute of lock statistics. =2D-=20 /"\ Best regards, | mlaier@freebsd.org \ / Max Laier | ICQ #67774661 X http://pf4freebsd.love2party.net/ | mlaier@EFnet / \ ASCII Ribbon Campaign | Against HTML Mail and News --nextPart1320325.ad8KbAYg12 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQBHm6XIXyyEoT62BG0RAvotAJ4jJFM0qpH91Y2ByEKyKTRmObD72QCfdniT PfTCHdbKTS0Kb/Bkwd5DXlM= =X5lq -----END PGP SIGNATURE----- --nextPart1320325.ad8KbAYg12--
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