[XFRM]: Always reroute in tunnel mode

Tunnel mode packets are rerouted if the tunnel destination
address is different from the original destination address,
otherwise the old route is used. This is inconsistent, the
old route might have been selected for a given output device
or using routing by tos/fwmark. Always choose a new route
in tunnel mode.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/xfrm4_policy.c

@@ -74,6 +74,7 @@ __xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 	for (i = 0; i < nx; i++) {
 		struct dst_entry *dst1 = dst_alloc(&xfrm4_dst_ops);
 		struct xfrm_dst *xdst;
+		int tunnel = 0;
 
 		if (unlikely(dst1 == NULL)) {
 			err = -ENOBUFS;
@@ -97,11 +98,12 @@ __xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 		if (xfrm[i]->props.mode) {
 			remote = xfrm[i]->id.daddr.a4;
 			local  = xfrm[i]->props.saddr.a4;
+			tunnel = 1;
 		}
 		header_len += xfrm[i]->props.header_len;
 		trailer_len += xfrm[i]->props.trailer_len;
 
-		if (remote != fl_tunnel.fl4_dst) {
+		if (tunnel) {
 			fl_tunnel.fl4_src = local;
 			fl_tunnel.fl4_dst = remote;
 			err = xfrm_dst_lookup((struct xfrm_dst **)&rt,

net/ipv6/xfrm6_policy.c

@@ -91,6 +91,7 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 	for (i = 0; i < nx; i++) {
 		struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
 		struct xfrm_dst *xdst;
+		int tunnel = 0;
 
 		if (unlikely(dst1 == NULL)) {
 			err = -ENOBUFS;
@@ -114,11 +115,12 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 		if (xfrm[i]->props.mode) {
 			remote = (struct in6_addr*)&xfrm[i]->id.daddr;
 			local  = (struct in6_addr*)&xfrm[i]->props.saddr;
+			tunnel = 1;
 		}
 		header_len += xfrm[i]->props.header_len;
 		trailer_len += xfrm[i]->props.trailer_len;
 
-		if (!ipv6_addr_equal(remote, &fl_tunnel.fl6_dst)) {
+		if (tunnel) {
 			ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 			ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 			err = xfrm_dst_lookup((struct xfrm_dst **) &rt,