net: Add sk_mark route lookup support for IPv4 listening sockets

Add support for route lookup using sk_mark on IPv4 listening sockets.

Signed-off-by: Atis Elsts <atis@mikrotik.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index a6e0e07..5ec678a 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -333,7 +333,8 @@
 	 * no easy way to do this.
 	 */
 	{
-		struct flowi fl = { .nl_u = { .ip4_u =
+		struct flowi fl = { .mark = sk->sk_mark,
+				    .nl_u = { .ip4_u =
 					      { .daddr = ((opt && opt->srr) ?
 							  opt->faddr :
 							  ireq->rmt_addr),