Date: Wed, 22 Aug 2007 02:02:17 +0200 From: Max Laier <max@love2party.net> To: freebsd-net@freebsd.org Cc: Alfred Perlstein <alfred@freebsd.org> Subject: Re: Allocating AF constants for vendors. Message-ID: <200708220202.23004.max@love2party.net> In-Reply-To: <20070821232956.GT87451@elvis.mu.org> References: <20070821232956.GT87451@elvis.mu.org>
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[-- Attachment #1 --] On Wednesday 22 August 2007, Alfred Perlstein wrote: > I trimmed the sender of this because I got it in private mail, that > said I thought it was a good bunch of questions so I am replying > to it. > > > 64? are you intending to bump AF_MAX or allocate them sequentially > > such that adding another AF will require AF_MAX to grow a lot? > > > > In general this seems like a bad idea to me. I suggest you need to > > (publicly) explain what you are doing and why this is a good idea. > > The goal here is to allow vendors to add their own constants without > worrying about conflicting with FreeBSD constants. It will allow > vendors to maintain some semblance of binary compatibility against > FreeBSD. > > If you look at libpcap: > > http://cvs.tcpdump.org/cgi-bin/cvsweb/libpcap/pcap/bpf.h?rev=1.15 > > You can see that Juniper has asked for some number of reserved > "families", in our case, I think it would be a bit greedy to > grow the list _just_ for Juniper, so I suggested something that > would work for every vendor. > > As far as implementation details, either one works for me, do you > have any particular preference? > > Other than the actual delta, will this have any noticeable negative > impact that you can see? DLTs are something very different to address families. DLTs are cheap as they are simply a number that is passed around. In contrast to that, there are some AF_MAX sized arrays in the kernel (e.g. if_afdata[] in struct ifnet or the routing tables) these will grow if you change AF_MAX - that's a bad thing! Could you provide a patch with what you have in mind so I (and other similarly confused people) can understand what you have in mind. Extending AF_MAX by 64 is out of the question, IMHO. -- /"\ Best regards, | mlaier@freebsd.org \ / Max Laier | ICQ #67774661 X http://pf4freebsd.love2party.net/ | mlaier@EFnet / \ ASCII Ribbon Campaign | Against HTML Mail and News [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQBGy30OXyyEoT62BG0RAjmMAJ0YXaeodrXZxB4UJ0Q2TIP87aKxGACfU0WT H2U6yTwii28tYwucnk1OfWs= =g2Na -----END PGP SIGNATURE-----
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