Date: Sun, 24 Aug 2008 01:49:56 +0200 From: Max Laier <max@love2party.net> To: freebsd-net@freebsd.org Cc: Roman Kurakin <rik@inse.ru>, Luigi Rizzo <rizzo@iet.unipi.it> Subject: Re: [Fwd: IPFW PATCH: make the IPFW_DEFUALT_RULE number constant non private] Message-ID: <200808240149.56698.max@love2party.net> In-Reply-To: <48B09ACD.1050600@localhost.inse.ru> References: <48B07DC5.2030203@localhost.inse.ru> <20080823231407.GA76471@onelab2.iet.unipi.it> <48B09ACD.1050600@localhost.inse.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sunday 24 August 2008 01:18:37 Roman Kurakin wrote: > Luigi Rizzo wrote: > > On Sun, Aug 24, 2008 at 02:03:50AM +0400, Roman Kurakin wrote: > > ... > > > >>> unless the tools you have in mind already include ip_fw.h (in which > >>> case the change is harmless and I have no objection), i think it would > >>> be better to export the value in a sysctl and let the tools fetch it > >>> from there, so they do not need to include the header. > >> > >> In fact, I am talking about ipfw(8) and natd(8). The first one uses > >> hard-coded value, the last one > >> pass rulenumbers to libalias(3) without a check, libalias(3) flushes > > > > ... > > > >> IIRC the natd(8) doesn't include ip_fw.h, but I do not see why it would > >> be better to export > >> this value via sysctl, not compiled in via #include<> for it. The only > > > > because ip_fw.h has a lot of stuff in it which in turn is likely > > to require more headers to build correctly. This is unnecessary bloat > > at compile time, and also less practical than the sysctl-based approach > > because it requires a binary update if the value ever changes. > > > > Besides, implementing the sysctl does not require to change the > > headers (thus saving rebuilds of the objects that depend on it), > > is one line in one file (ip_fw2.c) in the kernel, and one line to > > call sysctlbyname() in each of the userland program, which you'd > > need to change anyways; and because both ipfw(8) and natd(8) already > > use sysctl/sysctlbyname to read/write other similar values from the > > kernel, you are more consistent with the existing code and don't > > even need additional headers. > > Agreed, but including ip_fw.h for natd.c does not require any additional > headers. > All that needed looks like already there. > If some one point me to other utilities that need to be fixed I'll also > a sysctl for them. > These two already include enough of netinet includes, so if you not > strictly against adding > just one more include for natd, I'll prefer not to add a sysctl by right > now. There is no guarantee that the kernel or ipfw module you are running was built with the installed ip_fw.h or that IPFW_DEFAULT_RULE wasn't defined differently in the build environment. So a sysctl (or the like) is the *only* correct approach. Please fix it for real and don't just slap band-aid at it. Nice catch, by the way! > rik > > > At runtime the sysctl is obviously more expensive than reading a > > hardwired constant, but still a whole lot cheaper than the subsequent > > action (adding a rule to the firewall) so one won't notice. > > > > cheers > > luigi > > _______________________________________________ > > freebsd-net@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-net > > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" -- /"\ Best regards, | mlaier@freebsd.org \ / Max Laier | ICQ #67774661 X http://pf4freebsd.love2party.net/ | mlaier@EFnet / \ ASCII Ribbon Campaign | Against HTML Mail and News
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200808240149.56698.max>