The following reply was made to PR kern/179901; it has been noted by GNATS.
From: Mikolaj Golub <to.my.troc...@gmail.com> To: Michael Gmelin <free...@grem.de> Cc: Mikolaj Golub <troc...@freebsd.org>, bug-follo...@freebsd.org Subject: Re: kern/179901: [netinet] [patch] Multicast SO_REUSEADDR handled incorrectly Date: Thu, 27 Jun 2013 23:00:16 +0300 On Wed, Jun 26, 2013 at 03:03:40PM +0200, Michael Gmelin wrote: > Hi, > > I adapted the test code, you can find it at > > http://blog.grem.de/multicast.c > > Test output is: > > IPv4 Port 5555: > Bind using SO_REUSEADDR.......OK (expected) > Bind using SO_REUSEADDR.......OK (expected) > Bind using SO_REUSEPORT.......FAIL (NOT expected): Address already in > use IPv4 Port 5556: > Bind using SO_REUSEPORT.......OK (expected) > Bind using SO_REUSEPORT.......OK (expected) > Bind using SO_REUSEADDR.......OK (expected) > Bind using SO_REUSEPORT.......FAIL (NOT expected): Address already in > use IPv4 Port 5557: > Bind using SO_REUSEADDR x 2...OK (expected) > Bind using SO_REUSEADDR x 2...OK (expected) > Bind using SO_REUSEPORT.......FAIL (NOT expected): Address already in > use Bind using SO_REUSEADDR.......OK (expected) > Bind using SO_REUSEPORT.......FAIL (NOT expected): Address already in > use IPv4 Port 5558: > Bind without socketopts.......OK (expected) > Bind using SO_REUSEADDR.......FAIL (expected): Address already in use > Bind using SO_REUSEPORT.......FAIL (expected): Address already in use > IPv4 Port 5559: > Bind using SO_REUSEADDR.......OK (expected) > Bind without socketopts.......FAIL (expected): Address already in use > IPv4 Port 5560: > Bind using SO_REUSEPORT.......OK (expected) > Bind using SO_REUSEPORT.......OK (expected) > Bind without socketopts.......FAIL (expected): Address already in use > IPv6 Port 5555: > Bind using SO_REUSEADDR.......OK (expected) > Bind using SO_REUSEADDR.......OK (expected) > Bind using SO_REUSEPORT.......FAIL (NOT expected): Address already in > use IPv6 Port 5556: > Bind using SO_REUSEPORT.......OK (expected) > Bind using SO_REUSEPORT.......OK (expected) > Bind using SO_REUSEADDR.......OK (expected) > Bind using SO_REUSEPORT.......FAIL (NOT expected): Address already in > use IPv6 Port 5557: > Bind using SO_REUSEADDR x 2...OK (expected) > Bind using SO_REUSEADDR x 2...OK (expected) > Bind using SO_REUSEPORT.......FAIL (NOT expected): Address already in > use Bind using SO_REUSEADDR.......OK (expected) > Bind using SO_REUSEPORT.......FAIL (NOT expected): Address already in > use IPv6 Port 5558: > Bind without socketopts.......OK (expected) > Bind using SO_REUSEADDR.......FAIL (expected): Address already in use > Bind using SO_REUSEPORT.......FAIL (expected): Address already in use > IPv6 Port 5559: > Bind using SO_REUSEADDR.......OK (expected) > Bind without socketopts.......FAIL (expected): Address already in use > IPv6 Port 5560: > Bind using SO_REUSEPORT.......OK (expected) > Bind using SO_REUSEPORT.......OK (expected) > Bind without socketopts.......FAIL (expected): Address already in use > Thank you for testing! > So you maintained the old PORT/ADDR behavior, which I think is not such > a great idea. I would suggest to get another opinion on this, just > because it's broken now doesn't mean we have to perpetuate it - maybe we > should compare the behavior with other Unix(like) OSes like the other > BSDs and Linux to see how their implementations work - usually ported > software is not changed in that respect, so being compatible is > valuable. It is difficult to talk about portability in the case of SO_REUSEPORT. AFAIK, there is no SO_REUSEPORT in Linux and it is recommended to always use SO_REUSEADDR for multicast in portable code. It looks like in this case we will always have expected behavior with the proposed patch. > Besides my rant the code works as designed and seems to resemble the > behavior before r227207 correctly (I manually applied the patches to > 9.1-RELEASE). > > Fun fact: The code in ip6_output.c could have never worked in the first > place, since it used IN_MULTICAST instead of IN6_IS_ADDR_MULTICAST: > > if (IN_MULTICAST(ntohl(in6p->inp_laddr.s_addr))) > ... I don't insist on maintaining the old behaviour. But as actually we have 2 issues here (regression introduced by me in FreeBSD9 and historical behavior that looks wrong), with different priority, I would like to fix the issues separately. This way it will be easier to track the changes, e.g. when after a year it turns out that the second change has broken some other case. For now I am more concerned about having SO_REUSEADDR regression fixed in CURRENT and STABLE9 before 9.2. The patch is under review and I plan to commit it next week if it is ok. The second issue might require more discussion before commiting the change. -- Mikolaj Golub _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
