zebra: Abstract mac neigh installation into it's own function

Abstract the mac neigh installation for 169.254.0.1 into
it's own function that we can pass the mac address into.
This will allow a future commit to use this functionality
when we have the appropriate mac address from reading
optional attributes of a RA packet.

Signed-off-by: Donald Sharp <sharpd@cumuusnetworks.com>

2 files changed, 43 insertions, 7 deletions

diff --git a/zebra/interface.c b/zebra/interface.c
index ca90c18cf2..131b8598b0 100644
--- a/zebra/interface.c
+++ b/zebra/interface.c
@@ -136,6 +136,8 @@ static int if_zebra_new_hook(struct interface *ifp)
 	}
 #endif /* HAVE_RTADV */
 
+	memset(&zebra_if->neigh_mac[0], 0, 6);
+
 	/* Initialize installed address chains tree. */
 	zebra_if->ipv4_subnets =
 		route_table_init_with_delegate(&zebra_if_table_delegate);
@@ -802,19 +804,32 @@ static void ipv6_ll_address_to_mac(struct in6_addr *address, uint8_t *mac)
 	mac[5] = address->s6_addr[15];
 }
 
-void if_nbr_ipv6ll_to_ipv4ll_neigh_update(struct interface *ifp,
-					  struct in6_addr *address, int add)
+static bool mac_is_same(char *mac1, char *mac2)
+{
+	if (mac1[0] == mac2[0] &&
+	    mac1[1] == mac2[1] &&
+	    mac1[2] == mac2[2] &&
+	    mac1[3] == mac2[3] &&
+	    mac1[4] == mac2[4] &&
+	    mac1[5] == mac2[5])
+		return true;
+	else
+		return false;
+}
+
+void if_nbr_mac_to_ipv4ll_neigh_update(struct interface *ifp,
+				       char mac[6],
+				       struct in6_addr *address,
+				       int add)
 {
 	struct zebra_vrf *zvrf = vrf_info_lookup(ifp->vrf_id);
 	struct zebra_if *zif = ifp->info;
 	char buf[16] = "169.254.0.1";
 	struct in_addr ipv4_ll;
-	char mac[6];
 	ns_id_t ns_id;
 
 	inet_pton(AF_INET, buf, &ipv4_ll);
 
-	ipv6_ll_address_to_mac(address, (uint8_t *)mac);
 	ns_id = zvrf->zns->ns_id;
 
 	/*
@@ -823,10 +838,16 @@ void if_nbr_ipv6ll_to_ipv4ll_neigh_update(struct interface *ifp,
 	 *
 	 * supported message types are RTM_NEWNEIGH and RTM_DELNEIGH
 	 */
-	kernel_neigh_update(0, ifp->ifindex, ipv4_ll.s_addr, mac, 6, ns_id);
+	if (!mac_is_same(zif->neigh_mac, mac)) {
+		kernel_neigh_update(0, ifp->ifindex, ipv4_ll.s_addr,
+				    mac, 6, ns_id);
+
+		/* Add arp record */
+		kernel_neigh_update(add, ifp->ifindex, ipv4_ll.s_addr,
+				    mac, 6, ns_id);
+	}
 
-	/* Add arp record */
-	kernel_neigh_update(add, ifp->ifindex, ipv4_ll.s_addr, mac, 6, ns_id);
+	memcpy(&zif->neigh_mac[0], &mac[0], 6);
 
 	/*
 	 * We need to note whether or not we originated a v6
@@ -840,6 +861,16 @@ void if_nbr_ipv6ll_to_ipv4ll_neigh_update(struct interface *ifp,
 	zvrf->neigh_updates++;
 }
 
+void if_nbr_ipv6ll_to_ipv4ll_neigh_update(struct interface *ifp,
+					  struct in6_addr *address, int add)
+{
+
+	char mac[6];
+
+	ipv6_ll_address_to_mac(address, (uint8_t *)mac);
+	if_nbr_mac_to_ipv4ll_neigh_update(ifp, mac, address, add);
+}
+
 static void if_nbr_ipv6ll_to_ipv4ll_neigh_add_all(struct interface *ifp)
 {
 	if (listhead(ifp->nbr_connected)) {
diff --git a/zebra/interface.h b/zebra/interface.h
index 02a05e6146..b632d25c2a 100644
--- a/zebra/interface.h
+++ b/zebra/interface.h
@@ -279,6 +279,7 @@ struct zebra_if {
 	 * for bgp unnumbered?
 	 */
 	bool v6_2_v4_ll_neigh_entry;
+	char neigh_mac[6];
 	struct in6_addr v6_2_v4_ll_addr6;
 };
 
@@ -332,6 +333,10 @@ extern struct interface *if_link_per_ns(struct zebra_ns *, struct interface *);
 extern const char *ifindex2ifname_per_ns(struct zebra_ns *, unsigned int);
 
 extern void if_unlink_per_ns(struct interface *);
+extern void if_nbr_mac_to_ipv4ll_neigh_update(struct interface *fip,
+					      char mac[6],
+					      struct in6_addr *address,
+					      int add);
 extern void if_nbr_ipv6ll_to_ipv4ll_neigh_update(struct interface *ifp,
 						 struct in6_addr *address,
 						 int add);