Date: Thu, 24 May 2007 13:26:44 +0400 From: Gleb Smirnoff <glebius@FreeBSD.org> To: Andre Oppermann <andre@FreeBSD.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/netinet tcp_syncache.c Message-ID: <20070524092643.GC89017@FreeBSD.org> In-Reply-To: <4654D011.5040309@freebsd.org> References: <200705182113.l4ILD2qb044650@repoman.freebsd.org> <20070521073544.GP89017@FreeBSD.org> <4654D011.5040309@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, May 24, 2007 at 01:36:49AM +0200, Andre Oppermann wrote: A> Yes, these logs can be triggered remotely. Broken packets and spoofed A> packets may cause them. We're interested in the former. A> A> I'll do some benchmarks on the impact of the logging and then decide A> whether to put it under a sysctl. A> A> The reason it is unconditionally enabled is to see if non-compliant A> TCP stacks are out there that fail the very strong (but fully RFC and A> TCP-secure conform) checks. A> A> W/o logging we have no way of really knowing. Before we were possibly A> accepting stuff we shouldn't have (spoofing and attacks). Now we may A> drop stuff we perhaps should accept anyway. W/o logging diagnosing a A> TCP problem was very difficult and would need a lot cooperation with A> the PR submitter, if it was submitted at all. We normally only got a A> report of TCP 'not working'. Figuring out what went wrong was pretty A> much doing iterative shots into the dark and see if something squeaks. A> A> With logging I want to make things much more obvious and simpler to A> diagnose. Plus we get information in cases (from admins reading the A> logs) that were totally lost in the noise or not even attempted to A> be debugged. A> A> For our TCP maintainers (mostly I at the moment) and also 3rd parties A> this makes TCP trouble diagnosis much more accessible. Based on a A> log report and the OS name/version of the remote end we can pretty A> much tell right away what went wrong. This saves an order of a A> magnitude in debugging and fault analysis time. From many hours and A> email round trips to mere minutes and one or two information requests. I completely understand that this logging is very important in the process of refactoring the TCP code. I just think that the performance impact should be measured before merging this logging to RELENG_6. -- Totus tuus, Glebius. GLEBIUS-RIPN GLEB-RIPE
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20070524092643.GC89017>