Date: Tue, 10 Nov 2015 18:17:53 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 204438] setsockopt() handling of kern.ipc.maxsockbuf limit Message-ID: <bug-204438-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=204438 Bug ID: 204438 Summary: setsockopt() handling of kern.ipc.maxsockbuf limit Product: Base System Version: 11.0-CURRENT Hardware: Any OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: cameronsparr@gmail.com Hello, I'd like to put out a proposal for changing the way that the setsockopt() function handles the max socket buffer setting. Currently, it's a bit unintuitive that socket send and receive buffers (SO_RCVBUF & SO_SNDBUF) can not actually be set to the kern.ipc.maxsockbuf value, even though it is described as being possible in the man page: https://www.freebsd.org/cgi/man.cgi?query=setsockopt&sektion=2 This is because setsockopt() will error out if the value passed is over the _adjusted_ maximum, which on my system (amd64) turns out to be something like kern.ipc.maxsockbuf * 0.889 (kern.ipc.maxsockbuf * (1 << 11) / (256 + (1 << 11)) = kern.ipc.maxsockbuf * (2048) / (2304)). see here: https://github.com/freebsd/freebsd/blob/master/sys/kern/uipc_sockbuf.c#L420 and here: https://github.com/freebsd/freebsd/blob/master/sys/kern/uipc_sockbuf.c#L63-L64 I believe that the behavior could be made more intuitive by checking if the value passed is under the _actual_ max before erroring out, and if it is under the actual max, then set it to the adjusted max and continue the function, this would be a simple change and would look something like this (apologies for the whitespace diffs): https://github.com/sparrc/freebsd/commit/157f90c55d1d54d33f41c6f7517de1a9c5f5e229 FWIW, the linux kernel takes it a step further by never failing if setting the buffer over the maximum. It just takes whatever value it's given and sets it to min(given_value, max_value). see here: https://github.com/torvalds/linux/blob/master/net/core/sock.c#L762-L768. Not saying this is a good option, just pointing out that there is a precedent for doing something like this. I would be happy to make this change and submit a patch to phabricator if approved. Thanks all, Cameron -- You are receiving this mail because: You are the assignee for the bug.
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