util: Fix setting of IPV6_V6ONLY socket option

Currently we only call setsockopt() on IPV6_V6ONLY when we want to set it
to 1, which we typically do on all IPv6 sockets except those explicitly for
dual stack listening.  That's not quite right in two ways:

 * Although IPV6_V6ONLY==0 is normally the default on Linux, that can be
   changed with the net.ipv6.bindv6only sysctl.  It may also have different
   defaults on other OSes if we ever support them.  We know we need it off
   for dual stack sockets, so explicitly set it to 0 in that case.

 * At the same time setting IPV6_V6ONLY to 1 for IPv6 sockets bound to a
   specific address is harmless but pointless.  Don't set the option at all
   in this case, saving a syscall.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

0 files changed, 0 insertions, 0 deletions