[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: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/xfrm4_policy.c

@@ -35,6 +35,7 @@ __xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
 		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 @@ __xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 		.nl_u = {
 			.ip4_u = {
 				.saddr = local,
-				.daddr = remote
+				.daddr = remote,
+				.tos = fl->fl4_tos
 			}
 		}
 	};
@@ -230,6 +232,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl)
 	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)