zebra: Check both IPv4 and IPv6 NH before removing RMAC

IPv4 and IPv4-mapped IPv6 address of a VTEP is used as nexthops of EVPN
routes. Thus should check for both IPv4 and IPv6 before removing RMAC.
Otherwise, withdrawing the last route in one address family breaks
the other.

Signed-off-by: Xiao Liang <shaw.leon@gmail.com>

zebra/zebra_vxlan.c

@@ -1413,25 +1413,43 @@ static void zl3vni_remote_rmac_del(struct zebra_l3vni *zl3vni,
 				   struct zebra_mac *zrmac,
 				   struct ipaddr *vtep_ip)
 {
-	struct ipaddr ipv4_vtep;
+	struct ipaddr tmp_ip;
+	struct ipaddr *ipv4_vtep, *ipv6_nh;
 
-	if (!zl3vni_nh_lookup(zl3vni, vtep_ip)) {
-		memset(&ipv4_vtep, 0, sizeof(ipv4_vtep));
-		ipv4_vtep.ipa_type = IPADDR_V4;
-		if (vtep_ip->ipa_type == IPADDR_V6)
-			ipv4_mapped_ipv6_to_ipv4(&vtep_ip->ipaddr_v6,
-						 &ipv4_vtep.ipaddr_v4);
-		else
-			memcpy(&(ipv4_vtep.ipaddr_v4), &vtep_ip->ipaddr_v4,
-			       sizeof(struct in_addr));
+	memset(&tmp_ip, 0, sizeof(tmp_ip));
+	if (vtep_ip->ipa_type == IPADDR_V6) {
+		if (!IS_MAPPED_IPV6(&vtep_ip->ipaddr_v6)) {
+			zlog_warn("Unsupported IPv6 EVPN nexthop %pIA", vtep_ip);
+			return;
+		}
+		ipv4_vtep = &tmp_ip;
+		ipv6_nh = vtep_ip;
+		ipv4_vtep->ipa_type = IPADDR_V4;
+		ipv4_mapped_ipv6_to_ipv4(&ipv6_nh->ipaddr_v6,
+					 &ipv4_vtep->ipaddr_v4);
+	} else {
+		ipv4_vtep = vtep_ip;
+		ipv6_nh = &tmp_ip;
+		ipv6_nh->ipa_type = IPADDR_V6;
+		ipv4_to_ipv4_mapped_ipv6(&ipv6_nh->ipaddr_v6,
+					 ipv4_vtep->ipaddr_v4);
+	}
+
+	/*
+	 * We may have IPv4 and IPv4-mapped IPv6 address of the VTEP as
+	 * nexthops, but only IPv4 is inserted to rmac nh_list. Check for both
+	 * before deleting from rmac.
+	 */
+	if (!zl3vni_nh_lookup(zl3vni, ipv4_vtep) &&
+	    !zl3vni_nh_lookup(zl3vni, ipv6_nh)) {
 
 		/* remove nh from rmac's list */
-		l3vni_rmac_nh_list_nh_delete(zl3vni, zrmac, &ipv4_vtep);
+		l3vni_rmac_nh_list_nh_delete(zl3vni, zrmac, ipv4_vtep);
 		/* delete nh is same as current selected, fall back to
 		 * one present in the list
 		 */
 		if (IPV4_ADDR_SAME(&zrmac->fwd_info.r_vtep_ip,
-				   &ipv4_vtep.ipaddr_v4) &&
+				   &ipv4_vtep->ipaddr_v4) &&
 		    listcount(zrmac->nh_list)) {
 			struct ipaddr *vtep;
 
@@ -1440,7 +1458,7 @@ static void zl3vni_remote_rmac_del(struct zebra_l3vni *zl3vni,
 			if (IS_ZEBRA_DEBUG_VXLAN)
 				zlog_debug(
 					"L3VNI %u Remote VTEP nh change(%pIA -> %pI4) for RMAC %pEA",
-					zl3vni->vni, &ipv4_vtep,
+					zl3vni->vni, ipv4_vtep,
 					&zrmac->fwd_info.r_vtep_ip,
 					&zrmac->macaddr);