Date: Thu, 04 Sep 2014 10:42:59 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-net@freebsd.org Cc: Craig Rodrigues <rodrigc@freebsd.org>, "Andrey V. Elsukov" <ae@freebsd.org>, bugzilla-noreply@freebsd.org Subject: Re: [Bug 193246] Bug in IPv6 multicast join(), uncovered by Jenkins Message-ID: <3393302.jtrfEtP2nm@ralph.baldwin.cx> In-Reply-To: <CAG=rPVe05jnxrD8QDkvwThBhKz7GCECRKTjK=XenAhbKwUB%2BPw@mail.gmail.com> References: <bug-193246-2472@https.bugs.freebsd.org/bugzilla/> <54070758.2050405@FreeBSD.org> <CAG=rPVe05jnxrD8QDkvwThBhKz7GCECRKTjK=XenAhbKwUB%2BPw@mail.gmail.com>
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On Wednesday, September 03, 2014 06:39:53 AM Craig Rodrigues wrote: > On Wed, Sep 3, 2014 at 5:19 AM, Andrey V. Elsukov <ae@freebsd.org> wrote: > > On 03.09.2014 14:05, bugzilla-noreply@freebsd.org wrote: > > > > Hi, > > > > you said that this code works in linux. I looked in the linux kernel > > source, and I think it should return EINVAL too. > > > > net/ipv6/mcast.c:ipv6_sock_mc_join: > > 154 if (!ipv6_addr_is_multicast(addr)) > > 155 return -EINVAL; > > The code does work in Linux. However, you need to look at the > JDK source, not the Linux kernel source. > > In this file: > http://hg.openjdk.java.net/jdk7/jdk7/jdk/file/9b8c96f96a0f/src/solaris/nativ > e/java/net/PlainDatagramSocketImpl.c > > in the mcast_join_leave() function, there are two code paths: (1) > Linux, (2) Solaris. > > It looks like on Solaris, they support IPv4-mapped multicast addresses for > IPV6, and things work when they create an IPv6 socket, and then put an > IPv4-mapped multicast address in it. For Linux, they have specific > code paths in that function which seem to force creating an IPv4 > socket. >From looking at the source, it doesn't look like the Linux workaround (using IP_ADD_MEMBERSHIP on an AF_INET6 socket) will work on FreeBSD. I'm not sure how hard it would be to fix in6_mcast.c to support IPv4 groups. bms@ might know. -- John Baldwin
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