Date: Thu, 28 Jul 2016 22:14:12 +0000 From: bugzilla-noreply@freebsd.org To: apache@FreeBSD.org Subject: maintainer-feedback requested: [Bug 211430] devel/apr1: IPv6 to IPv4 fallback does not work in serf Message-ID: <bug-211430-16115-eLAiLUg8pV@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-211430-16115@https.bugs.freebsd.org/bugzilla/> References: <bug-211430-16115@https.bugs.freebsd.org/bugzilla/>
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Don Lewis <truckman@FreeBSD.org> has reassigned Bugzilla Automation <bugzilla@FreeBSD.org>'s request for maintainer-feedback to apache@FreeBSD.= org: Bug 211430: devel/apr1: IPv6 to IPv4 fallback does not work in serf https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D211430 --- Description --- Created attachment 173081 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D173081&action= =3Dedit patch to modify apr1 poll() emulation to match behavior expected by serf. serf depends on the poll emulation in apr returning a POLLERR event if a non-blocking connect() attempt fails in order to trigger an IPv6 -> IPv4 fallback, or a fallback to another address for a multi-homed host. On Free= BSD, the poll emulation is done using kqueue, and the result returned by the pol= l() emulation is POLLIN + POLLHUP. connect(4,{ AF_INET6 [xxxx:xxxx:xxxx:xxxx::xxxx]:80 },28) ERR#36 'Operation= now in progress' gettimeofday({ 1469515046.979614 },0x0) =3D 0 (0x0) kevent(3,{ 4,EVFILT_READ,EV_ADD,0x0,0x0,0x805491300 },1,0x0,0,0x0) =3D 0 (0= x0) kevent(3,{ 4,EVFILT_WRITE,EV_ADD,0x0,0x0,0x805491300 },1,0x0,0,0x0) =3D 0 (= 0x0) kevent(3,0x0,0,{ 4,EVFILT_READ,EV_EOF,NOTE_LOWAT|0x3c,0x0,0x805491300 4,EVFILT_WRITE,EV_EOF,NOTE_LOWAT|0x3c,0x8000,0x805491300 },32,{ 0.500000000= }) =3D 2 (0x2) When serf sees this, it calls read(), which then fails with ECONNREFUSED (or whatever), which is not even a documented read() errno value. read(4,0x80549c064,8000) ERR#61 'Connection refused' What that occurs, serf closes the socket an any other addresses are not tri= ed. The attached patch modifies apr to return what serf expects in the case of a non-blocking connect() failure. Unfortunately, I did not see an easy way of handling ETIMEDOUT since that error can either be caused by connect failing= or after the connection is established. The poll emulation might need to differentiate between those two cases. This problem affects users of svn who don't have working IPv6 connectivity = to the FreeBSD svn servers.
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