sctp: verify the bind address with the tb_id from l3mdev

After binding to a l3mdev, it should use the route table from the
corresponding VRF to verify the addr when binding to an address.

Note ipv6 doesn't need it, as binding to ipv6 address does not
verify the addr with route lookup.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/protocol.c

@@ -351,10 +351,13 @@ static int sctp_v4_addr_valid(union sctp_addr *addr,
 /* Should this be available for binding?   */
 static int sctp_v4_available(union sctp_addr *addr, struct sctp_sock *sp)
 {
-	struct net *net = sock_net(&sp->inet.sk);
-	int ret = inet_addr_type(net, addr->v4.sin_addr.s_addr);
-
+	struct sock *sk = &sp->inet.sk;
+	struct net *net = sock_net(sk);
+	int tb_id = RT_TABLE_LOCAL;
+	int ret;
 
+	tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ?: tb_id;
+	ret = inet_addr_type_table(net, addr->v4.sin_addr.s_addr, tb_id);
 	if (addr->v4.sin_addr.s_addr != htonl(INADDR_ANY) &&
 	   ret != RTN_LOCAL &&
 	   !sp->inet.freebind &&