Re: [PATCH net-next 03/14] gtp: Call common functions to get tunnel routes and add dst_cache

From: Tom Herbert <redacted>
Date: Mon, 18 Sep 2017 17:38:53 -0700

Call ip_tunnel_get_route and dst_cache to pdp context which should
improve performance by obviating the need to perform a route lookup
on every packet.

Signed-off-by: Tom Herbert <redacted>

Not caused by your changes, but something to think about:

-static struct rtable *ip4_route_output_gtp(struct flowi4 *fl4,
-					   const struct sock *sk,
-					   __be32 daddr)
-{
-	memset(fl4, 0, sizeof(*fl4));
-	fl4->flowi4_oif		= sk->sk_bound_dev_if;
-	fl4->daddr		= daddr;
-	fl4->saddr		= inet_sk(sk)->inet_saddr;
-	fl4->flowi4_tos		= RT_CONN_FLAGS(sk);
-	fl4->flowi4_proto	= sk->sk_protocol;
-
-	return ip_route_output_key(sock_net(sk), fl4);
-}

This and the new dst caching code ignores any source address selection
done by ip_route_output_key() or the new tunnel route lookup helpers.

Either source address selection should be respected, or if saddr will
never be modified by a route lookup for some specific reason here,
that should be documented.