[SCTP] Add support for ip_nonlocal_bind sysctl & IP_FREEBIND socket option

Signed-off-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/af_inet.c

@@ -1181,6 +1181,7 @@ EXPORT_SYMBOL(inet_stream_connect);
 EXPORT_SYMBOL(inet_stream_ops);
 EXPORT_SYMBOL(inet_unregister_protosw);
 EXPORT_SYMBOL(net_statistics);
+EXPORT_SYMBOL(sysctl_ip_nonlocal_bind);
 
 #ifdef INET_REFCNT_DEBUG
 EXPORT_SYMBOL(inet_sock_nr);

net/sctp/protocol.c

@@ -378,10 +378,13 @@ static int sctp_v4_available(union sctp_addr *addr, struct sctp_sock *sp)
 {
 	int ret = inet_addr_type(addr->v4.sin_addr.s_addr);
 
-	/* FIXME: ip_nonlocal_bind sysctl support. */
 
-	if (addr->v4.sin_addr.s_addr != INADDR_ANY && ret != RTN_LOCAL)
+	if (addr->v4.sin_addr.s_addr != INADDR_ANY &&
+	   ret != RTN_LOCAL &&
+	   !sp->inet.freebind &&
+	   !sysctl_ip_nonlocal_bind)
 		return 0;
+
 	return 1;
 }