tnl-neigh-cache: Unwildcard flow members before inspecting them.

tnl_neigh_snoop() is part of the translation.  During translation we
have to unwildcard all the fields we examine to make a decision.

tnl_arp_snoop() and tnl_nd_snoop() failed to unwildcard fileds in case
of failure.  The solution is to do unwildcarding before the field is
inspected.

Signed-off-by: Daniele Di Proietto <diproiettod@vmware.com>
Acked-by: Jarno Rajahalme <jarno@ovn.org>

lib/flow.h

@@ -998,6 +998,13 @@ pkt_metadata_from_flow(struct pkt_metadata *md, const struct flow *flow)
     md->ct_label = flow->ct_label;
 }
 
+/* Often, during translation we need to read a value from a flow('FLOW') and
+ * unwildcard the corresponding bits in the wildcards('WC').  This macro makes
+ * it easier to do that. */
+
+#define FLOW_WC_GET_AND_MASK_WC(FLOW, WC, FIELD) \
+    (((WC) ? WC_MASK_FIELD(WC, FIELD) : NULL), ((FLOW)->FIELD))
+
 static inline bool is_ip_any(const struct flow *flow)
 {
     return dl_type_is_ip_any(flow->dl_type);

lib/tnl-neigh-cache.c

@@ -111,7 +111,7 @@ tnl_neigh_delete(struct tnl_neigh_entry *neigh)
 
 static void
 tnl_neigh_set__(const char name[IFNAMSIZ], const struct in6_addr *dst,
-              const struct eth_addr mac)
+                const struct eth_addr mac)
 {
     ovs_mutex_lock(&mutex);
     struct tnl_neigh_entry *neigh = tnl_neigh_lookup__(name, dst);
@@ -162,12 +162,13 @@ tnl_arp_snoop(const struct flow *flow, struct flow_wildcards *wc,
 
 static int
 tnl_nd_snoop(const struct flow *flow, struct flow_wildcards *wc,
-              const char name[IFNAMSIZ])
+             const char name[IFNAMSIZ])
 {
-    if (flow->dl_type != htons(ETH_TYPE_IPV6) ||
-        flow->nw_proto != IPPROTO_ICMPV6 ||
-        flow->tp_dst != htons(0) ||
-        flow->tp_src != htons(ND_NEIGHBOR_ADVERT)) {
+    if (flow->dl_type != htons(ETH_TYPE_IPV6)
+        || FLOW_WC_GET_AND_MASK_WC(flow, wc, nw_proto) != IPPROTO_ICMPV6
+        || FLOW_WC_GET_AND_MASK_WC(flow, wc, tp_dst) != htons(0)
+        || FLOW_WC_GET_AND_MASK_WC(flow, wc, tp_src)
+           != htons(ND_NEIGHBOR_ADVERT)) {
         return EINVAL;
     }