gluster: IPv6 single stack support

Summary:
- This diff changes all locations in the code to prefer inet6 family
  instead of inet.  This will allow change GlusterFS to operate
  via IPv6 instead of IPv4 for all internal operations while still
  being able to serve (FUSE or NFS) clients via IPv4.
- The changes apply to NFS as well.
- This diff ports D1892990, D1897341 & D1896522 to the 3.8 branch.

Test Plan: Prove tests!

Reviewers: dph, rwareing

Signed-off-by: Shreyas Siravara <sshreyas@fb.com>

Change-Id: I34fdaaeb33c194782255625e00616faf75d60c33
Reviewed-on: http://review.gluster.org/16059
Reviewed-by: Shreyas Siravara <sshreyas@fb.com>
Tested-by: Shreyas Siravara <sshreyas@fb.com>
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/rpc/rpc-transport/socket/src/socket.c b/rpc/rpc-transport/socket/src/socket.c
index 4244883a5db..bfcc01b73b7 100644
--- a/rpc/rpc-transport/socket/src/socket.c
+++ b/rpc/rpc-transport/socket/src/socket.c
@@ -3009,6 +3009,21 @@ socket_connect (rpc_transport_t *this, int port)
                         }
                 }
 
+                /* Make sure we are not vulnerable to someone setting
+                 * net.ipv6.bindv6only to 1 so that gluster services are
+                 * avalable over IPv4 & IPv6.
+                 */
+                int disable_v6only = 0;
+
+                if (setsockopt (priv->sock, IPPROTO_IPV6, IPV6_V6ONLY,
+                                (void *)&disable_v6only,
+                                sizeof (disable_v6only)) < 0) {
+                        gf_log (this->name, GF_LOG_WARNING,
+                               "Error disabling sockopt IPV6_V6ONLY: \"%s\"",
+                               strerror (errno));
+                }
+
+
                 if (priv->nodelay && (sa_family != AF_UNIX)) {
                         ret = __socket_nodelay (priv->sock);