Date: Tue, 12 Jul 2011 10:16:56 +0400 From: "Alexander V. Chernikov" <melifaro@ipfw.ru> To: Garrett Cooper <yanegomi@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: [PATCH] Remove dead code in netstat from route.c Message-ID: <4E1BE6D8.60805@ipfw.ru> In-Reply-To: <CAGH67wS1EQFkmCKiv-VPrJFc_JXV5oTjfmht-anqbmpibJkMfQ@mail.gmail.com> References: <CAGH67wS1EQFkmCKiv-VPrJFc_JXV5oTjfmht-anqbmpibJkMfQ@mail.gmail.com>
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Garrett Cooper wrote: > Hi, > While trying to determine how to print out routes via kvm for > net-snmp, I noticed that there's a chunk of code from the 4.4 BSD Lite > days that isn't executed in netstat as NewTree is always 0. The > following patch removes that dead code and gets the FreeBSD source for > netstat more in line with NetBSD and OpenBSD's copy. > Thanks! Hello! This code is still working (I've tested it several months ago). Using RT_DUMP sysctl gives us less information than KVM, but this is much more better way of requesting infromation: KVM heavily assumes RADIX rtee is used and simply implement walking the tree in userland (p_tree()) which is quite hackish. Since some dynamic routing software can change massive amounts of data at once (BGP session with full-view going up/down) or physical interface with several hundred vlans goes up/down - requesting routing data via KVM can lead to fully unexpected behaviour. Calling this on regular basis on net-snmp is not the best thing one can do. Additionally, there can be address families where RADIX is unnecessary complicated since only direct key match is required (MPLS, for example). Moving from RADIX implementation for such family will require a lot of 'if (af == AF_MPLS)' code in many base userland utilities since assumption that RADIX is used do exists in many places, unfortunately. Requesting routes via KVM is completely undocumented and kernel internals dependent way. From the other side, NET_RT_DUMP sysctl is documented in sysctl(3) and is used by all major routing software (quagga, bird,openbgp). It also brings us more RADIX-dependent which should be avoided. > -Garrett > > > ------------------------------------------------------------------------ > > _______________________________________________ > 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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