Date: Wed, 26 Mar 2008 10:31:12 -0700 From: Julian Elischer <julian@elischer.org> To: vadim_nuclight@mail.ru Cc: freebsd-hackers@freebsd.org, freebsd-ipfw@freebsd.org Subject: Re: [HEADS UP!] IPFW Ideas: possible SoC 2008 candidate Message-ID: <47EA8860.3060709@elischer.org> In-Reply-To: <slrnfuk3lf.egh.vadim_nuclight@hostel.avtf.net> References: <slrnfud9lu.1rus.vadim_nuclight@hostel.avtf.net> <47E79636.1000909@FreeBSD.org> <47E7EAA8.7020101@elischer.org> <slrnfuk3lf.egh.vadim_nuclight@hostel.avtf.net>
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Vadim Goncharov wrote: > Hi Julian Elischer! > > On Mon, 24 Mar 2008 10:53:44 -0700; Julian Elischer wrote about 'Re: [HEADS UP!] IPFW Ideas: possible SoC 2008 candidate': > >> here are some of my ideas for ipfw changes: > >> 1/ redo locking so that packets do not have to get locks on the >> structure... I have several ideas on this > > Currently the main need for locking arises for rule byte/packet counters. The > easiest short-term solution The main need for locking is that the rules can be changed while a processor is traversing the rule set. > >> 2/ allow separate firewalls to be used at different parts of the >> network stack (i.e allow multiple taboe sto co-exist) there are many places that ipfw is currently callable from. ip_input(), ip_output(), ether_demux(), if_brige, ether_output() it would be interesting tobe able to have differnt firewalls in these places (possibly per interface) so that state (e.g. keep_state) can be kept seprately for one place then from another. for example you may not want the result of 'keep state' on an external interface to necessarily affect what happens to packets from the same session when viewed traversing an internal interface. Currently on my more complex ipfw rule sets I break the rule sets out so that packets in different places traverse different rules but it would be nice to have it explicitly supported. > > Umm, could you explain it a little?.. > >> 3/ possibly keeping per CPU stats.. > > How that would be represented to user? it wouldn't.. you'd add them together before presenting them. but every time a packet changes a counter that is shared, there is a chance that it is being altered by another processor, so if you have fine grained locking in ipfw, you really should use atomic adds, which are slow, or accept possibl collisions (which might be ok) but still cause a lot of cross cpu TLB flushing. > _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"
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