SCTP: change sctp_ctl_sock_init() to try IPv4 if IPv6 fails

Change sctp_ctl_sock_init() to try IPv4 if IPv6 socket registration
fails.  Required if the IPv6 module is loaded with "disable=1", else
SCTP will fail to load.

Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 3 deletions

diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 4e6638449639..c4986d0f7419 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -717,15 +717,20 @@ static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
 static int sctp_ctl_sock_init(void)
 {
         int err;
-        sa_family_t family;
+        sa_family_t family = PF_INET;
 
         if (sctp_get_pf_specific(PF_INET6))
                 family = PF_INET6;
-        else
-                family = PF_INET;
 
         err = inet_ctl_sock_create(&sctp_ctl_sock, family,
                                    SOCK_SEQPACKET, IPPROTO_SCTP, &init_net);
+
+        /* If IPv6 socket could not be created, try the IPv4 socket */
+        if (err < 0 && family == PF_INET6)
+                err = inet_ctl_sock_create(&sctp_ctl_sock, AF_INET,
+                                           SOCK_SEQPACKET, IPPROTO_SCTP,
+                                           &init_net);
+
         if (err < 0) {
                 printk(KERN_ERR
                        "SCTP: Failed to create the SCTP control socket.\n");