ipv4: Create and use route lookup helpers.

The idea here is this minimizes the number of places one has to edit
in order to make changes to how flows are defined and used.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 35a5020..807d83c 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1157,22 +1157,10 @@
 	daddr = inet->inet_daddr;
 	if (inet->opt && inet->opt->srr)
 		daddr = inet->opt->faddr;
-	{
-	struct flowi fl = {
-		.oif = sk->sk_bound_dev_if,
-		.mark = sk->sk_mark,
-		.fl4_dst = daddr,
-		.fl4_src = inet->inet_saddr,
-		.fl4_tos = RT_CONN_FLAGS(sk),
-		.proto = sk->sk_protocol,
-		.flags = inet_sk_flowi_flags(sk),
-		.fl_ip_sport = inet->inet_sport,
-		.fl_ip_dport = inet->inet_dport,
-	};
-
-	security_sk_classify_flow(sk, &fl);
-	rt = ip_route_output_flow(sock_net(sk), &fl, sk);
-	}
+	rt = ip_route_output_ports(sock_net(sk), sk, daddr, inet->inet_saddr,
+				   inet->inet_dport, inet->inet_sport,
+				   sk->sk_protocol, RT_CONN_FLAGS(sk),
+				   sk->sk_bound_dev_if);
 	if (!IS_ERR(rt)) {
 		err = 0;
 		sk_setup_caps(sk, &rt->dst);