[IPSEC]: Use TOS when doing tunnel lookups

We should use the TOS because it's one of the routing keys.  It also
means that we update the correct routing cache entry when PMTU occurs.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 45f7ae5..f285bbf 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -35,6 +35,7 @@
 		if (xdst->u.rt.fl.oif == fl->oif &&	/*XXX*/
 		    xdst->u.rt.fl.fl4_dst == fl->fl4_dst &&
 	    	    xdst->u.rt.fl.fl4_src == fl->fl4_src &&
+	    	    xdst->u.rt.fl.fl4_tos == fl->fl4_tos &&
 		    xfrm_bundle_ok(xdst, fl, AF_INET)) {
 			dst_clone(dst);
 			break;
@@ -61,7 +62,8 @@
 		.nl_u = {
 			.ip4_u = {
 				.saddr = local,
-				.daddr = remote
+				.daddr = remote,
+				.tos = fl->fl4_tos
 			}
 		}
 	};
@@ -230,6 +232,7 @@
 	fl->proto = iph->protocol;
 	fl->fl4_dst = iph->daddr;
 	fl->fl4_src = iph->saddr;
+	fl->fl4_tos = iph->tos;
 }
 
 static inline int xfrm4_garbage_collect(void)