use inet_listen()/inet_connect() to support ipv6 migration

Use help functions in qemu-socket.c for tcp migration,
which already support ipv6 addresses.

Currently errp will be set to UNDEFINED_ERROR when migration fails,
qemu would output "migration failed: ...", and current user can
see a message("An undefined error has occurred") in monitor.

This patch changed tcp_start_outgoing_migration()/inet_connect()
/inet_connect_opts(), socket error would be passed back,
then current user can see a meaningful err message in monitor.

Qemu will exit if listening fails, so output socket error
to qemu stderr.

For IPv6 brackets must be mandatory if you require a port.
Referencing to RFC5952, the recommended format is:
  [2312::8274]:5200

test status: Successed
listen side: qemu-kvm .... -incoming tcp:[2312::8274]:5200
client side: qemu-kvm ...
             (qemu) migrate -d tcp:[2312::8274]:5200

Signed-off-by: Amos Kong <akong@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/vl.c b/vl.c
index 91b18bca59..5ed8f0546b 100644
--- a/vl.c
+++ b/vl.c
@@ -3629,8 +3629,13 @@ int main(int argc, char **argv, char **envp)
     }
 
     if (incoming) {
-        int ret = qemu_start_incoming_migration(incoming);
+        Error *errp = NULL;
+        int ret = qemu_start_incoming_migration(incoming, &errp);
         if (ret < 0) {
+            if (error_is_set(&errp)) {
+                fprintf(stderr, "Migrate: %s\n", error_get_pretty(errp));
+                error_free(errp);
+            }
             fprintf(stderr, "Migration failed. Exit code %s(%d), exiting.\n",
                     incoming, ret);
             exit(ret);