bgpd: fix ipv4-mapped ipv6 on non 6pe

bgpd/bgp_nht.c

@@ -320,11 +320,6 @@ int bgp_find_or_add_nexthop(struct bgp *bgp_route, struct bgp *bgp_nexthop,
 			afi = BGP_ATTR_MP_NEXTHOP_LEN_IP6(pi->attr) ? AFI_IP6
 								    : AFI_IP;
 
-		/* Validation for the ipv4 mapped ipv6 nexthop. */
-		if (IS_MAPPED_IPV6(&pi->attr->mp_nexthop_global)) {
-			afi = AFI_IP;
-		}
-
 		/* This will return true if the global IPv6 NH is a link local
 		 * addr */
 		if (make_prefix(afi, pi, &p) < 0)
@@ -1043,19 +1038,11 @@ static int make_prefix(int afi, struct bgp_path_info *pi, struct prefix *p)
 			p->u.prefix4 = p_orig->u.prefix4;
 			p->prefixlen = p_orig->prefixlen;
 		} else {
-			if (IS_MAPPED_IPV6(&pi->attr->mp_nexthop_global)) {
-				ipv4_mapped_ipv6_to_ipv4(
-					&pi->attr->mp_nexthop_global, &ipv4);
-				p->u.prefix4 = ipv4;
-				p->prefixlen = IPV4_MAX_BITLEN;
-			} else {
-				if (p_orig->family == AF_EVPN)
-					p->u.prefix4 =
-						pi->attr->mp_nexthop_global_in;
-				else
-					p->u.prefix4 = pi->attr->nexthop;
-				p->prefixlen = IPV4_MAX_BITLEN;
-			}
+			if (p_orig->family == AF_EVPN)
+				p->u.prefix4 = pi->attr->mp_nexthop_global_in;
+			else
+				p->u.prefix4 = pi->attr->nexthop;
+			p->prefixlen = IPV4_MAX_BITLEN;
 		}
 		break;
 	case AFI_IP6:
@@ -1071,6 +1058,7 @@ static int make_prefix(int afi, struct bgp_path_info *pi, struct prefix *p)
 			/* If we receive MP_REACH nexthop with ::(LL)
 			 * or LL(LL), use LL address as nexthop cache.
 			 */
+			p->prefixlen = IPV6_MAX_BITLEN;
 			if (pi->attr &&
 			    pi->attr->mp_nexthop_len ==
 				    BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL &&
@@ -1085,15 +1073,22 @@ static int make_prefix(int afi, struct bgp_path_info *pi, struct prefix *p)
 				 pi->attr->mp_nexthop_len ==
 					 BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL) {
 				if (CHECK_FLAG(pi->attr->nh_flags,
-					       BGP_ATTR_NH_MP_PREFER_GLOBAL))
-					p->u.prefix6 =
-						pi->attr->mp_nexthop_global;
-				else
+					       BGP_ATTR_NH_MP_PREFER_GLOBAL)) {
+					if (IS_MAPPED_IPV6(
+						    &pi->attr->mp_nexthop_global)) {
+						ipv4_mapped_ipv6_to_ipv4(
+							&pi->attr->mp_nexthop_global,
+							&ipv4);
+						p->u.prefix4 = ipv4;
+						p->prefixlen = IPV4_MAX_BITLEN;
+					} else
+						p->u.prefix6 =
+							pi->attr->mp_nexthop_global;
+				} else
 					p->u.prefix6 =
 						pi->attr->mp_nexthop_local;
 			} else
 				p->u.prefix6 = pi->attr->mp_nexthop_global;
-			p->prefixlen = IPV6_MAX_BITLEN;
 		}
 		break;
 	default:

bgpd/bgp_route.c

@@ -9629,10 +9629,7 @@ void route_vty_out(struct vty *vty, const struct prefix *p,
 				json_object_string_add(json_nexthop_ll, "scope",
 						       "link-local");
 
-				if ((IPV6_ADDR_CMP(&attr->mp_nexthop_global,
-						   &attr->mp_nexthop_local) !=
-				     0) &&
-				    !CHECK_FLAG(attr->nh_flags,
+				if (!CHECK_FLAG(attr->nh_flags,
 						BGP_ATTR_NH_MP_PREFER_GLOBAL))
 					json_object_boolean_true_add(
 						json_nexthop_ll, "used");

bgpd/bgp_updgrp_packet.c

@@ -525,12 +525,9 @@ struct stream *bpacket_reformat_for_peer(struct bpacket *pkt,
 
 		if (peer->nexthop.v4.s_addr != INADDR_ANY &&
 		    (IN6_IS_ADDR_UNSPECIFIED(mod_v6nhg) ||
-		     (peer->connection->su.sa.sa_family == AF_INET &&
-		      paf->afi == AFI_IP6))) {
-			/* set a IPv4 mapped IPv6 address if no global IPv6
-			 * address is found or if announcing IPv6 prefix
-			 * over an IPv4 BGP session.
-			 */
+		     (IN6_IS_ADDR_LINKLOCAL(mod_v6nhg) &&
+		      peer->connection->su.sa.sa_family == AF_INET6 &&
+		      paf->afi == AFI_IP))) {
 			ipv4_to_ipv4_mapped_ipv6(mod_v6nhg, peer->nexthop.v4);
 			gnh_modified = 1;
 		}

bgpd/bgp_zebra.c

@@ -303,11 +303,12 @@ static int bgp_ifp_down(struct interface *ifp)
 
 static int bgp_interface_address_add(ZAPI_CALLBACK_ARGS)
 {
-	struct connected *ifc;
+	struct connected *ifc, *connected;
 	struct bgp *bgp;
 	struct peer *peer;
 	struct prefix *addr;
 	struct listnode *node, *nnode;
+	bool v6_ll_in_nh_global;
 	afi_t afi;
 	safi_t safi;
 
@@ -325,56 +326,70 @@ static int bgp_interface_address_add(ZAPI_CALLBACK_ARGS)
 	if (!bgp)
 		return 0;
 
-	if (if_is_operative(ifc->ifp)) {
-		bgp_connected_add(bgp, ifc);
+	if (!if_is_operative(ifc->ifp))
+		return 0;
 
-		/* If we have learnt of any neighbors on this interface,
-		 * check to kick off any BGP interface-based neighbors,
-		 * but only if this is a link-local address.
-		 */
-		if (IN6_IS_ADDR_LINKLOCAL(&ifc->address->u.prefix6)
-		    && !list_isempty(ifc->ifp->nbr_connected))
-			bgp_start_interface_nbrs(bgp, ifc->ifp);
-		else {
-			addr = ifc->address;
+	bgp_connected_add(bgp, ifc);
 
-			for (ALL_LIST_ELEMENTS(bgp->peer, node, nnode, peer)) {
-				if (addr->family == AF_INET)
-					continue;
+	/* If we have learnt of any neighbors on this interface,
+	 * check to kick off any BGP interface-based neighbors,
+	 * but only if this is a link-local address.
+	 */
+	if (IN6_IS_ADDR_LINKLOCAL(&ifc->address->u.prefix6) &&
+	    !list_isempty(ifc->ifp->nbr_connected))
+		bgp_start_interface_nbrs(bgp, ifc->ifp);
+	else if (ifc->address->family == AF_INET6 &&
+		 !IN6_IS_ADDR_LINKLOCAL(&ifc->address->u.prefix6)) {
+		addr = ifc->address;
 
-				/*
-				 * If the Peer's interface name matches the
-				 * interface name for which BGP received the
-				 * update and if the received interface address
-				 * is a globalV6 and if the peer is currently
-				 * using a v4-mapped-v6 addr or a link local
-				 * address, then copy the Rxed global v6 addr
-				 * into peer's v6_global and send updates out
-				 * with new nexthop addr.
-				 */
-				if ((peer->conf_if &&
-				     (strcmp(peer->conf_if, ifc->ifp->name) ==
-				      0)) &&
-				    !IN6_IS_ADDR_LINKLOCAL(&addr->u.prefix6) &&
-				    ((IS_MAPPED_IPV6(
-					     &peer->nexthop.v6_global)) ||
-				     IN6_IS_ADDR_LINKLOCAL(
-					     &peer->nexthop.v6_global))) {
-
-					if (bgp_debug_zebra(ifc->address)) {
-						zlog_debug(
-							"Update peer %pBP's current intf addr %pI6 and send updates",
-							peer,
-							&peer->nexthop
-								 .v6_global);
-					}
-					memcpy(&peer->nexthop.v6_global,
-					       &addr->u.prefix6,
-					       IPV6_MAX_BYTELEN);
-					FOREACH_AFI_SAFI (afi, safi)
-						bgp_announce_route(peer, afi,
-								   safi, true);
+		for (ALL_LIST_ELEMENTS(bgp->peer, node, nnode, peer)) {
+			v6_ll_in_nh_global = false;
+
+			if (IN6_IS_ADDR_LINKLOCAL(&peer->nexthop.v6_global)) {
+				frr_each (if_connected, ifc->ifp->connected,
+					  connected) {
+					if (connected->address->family !=
+					    AF_INET6)
+						continue;
+					if (!IPV6_ADDR_SAME(&connected->address
+								     ->u.prefix6,
+							    &peer->nexthop
+								     .v6_global))
+						continue;
+					/* peer->nexthop.v6_global contains a link-local address
+					 * that needs to be replaced by the global address.
+					 */
+					v6_ll_in_nh_global = true;
+					break;
+				}
+			}
+
+			/*
+			 * If the Peer's interface name matches the
+			 * interface name for which BGP received the
+			 * update and if the received interface address
+			 * is a globalV6 and if the peer is currently
+			 * using a v4-mapped-v6 addr or a link local
+			 * address, then copy the Rxed global v6 addr
+			 * into peer's v6_global and send updates out
+			 * with new nexthop addr.
+			 */
+			if (v6_ll_in_nh_global ||
+			    (peer->conf_if &&
+			     strcmp(peer->conf_if, ifc->ifp->name) == 0 &&
+			     (IS_MAPPED_IPV6(&peer->nexthop.v6_global) ||
+			      IN6_IS_ADDR_LINKLOCAL(&peer->nexthop.v6_global)))) {
+				if (bgp_debug_zebra(ifc->address)) {
+					zlog_debug("Update peer %pBP's current intf global addr from %pI6 to %pI6 and send updates",
+						   peer,
+						   &peer->nexthop.v6_global,
+						   &addr->u.prefix6);
 				}
+				memcpy(&peer->nexthop.v6_global,
+				       &addr->u.prefix6, IPV6_MAX_BYTELEN);
+				FOREACH_AFI_SAFI (afi, safi)
+					bgp_announce_route(peer, afi, safi,
+							   true);
 			}
 		}
 	}
@@ -385,10 +400,14 @@ static int bgp_interface_address_add(ZAPI_CALLBACK_ARGS)
 static int bgp_interface_address_delete(ZAPI_CALLBACK_ARGS)
 {
 	struct listnode *node, *nnode;
-	struct connected *ifc;
+	struct connected *ifc, *connected;
 	struct peer *peer;
 	struct bgp *bgp;
 	struct prefix *addr;
+	struct in6_addr *v6_global = NULL;
+	struct in6_addr *v6_local = NULL;
+	afi_t afi;
+	safi_t safi;
 
 	bgp = bgp_lookup_by_vrf_id(vrf_id);
 
@@ -407,7 +426,18 @@ static int bgp_interface_address_delete(ZAPI_CALLBACK_ARGS)
 
 	addr = ifc->address;
 
-	if (bgp) {
+	if (bgp && addr->family == AF_INET6 &&
+	    !IN6_IS_ADDR_LINKLOCAL(&addr->u.prefix6)) {
+		/* find another IPv6 global if possible and find the IPv6 link-local */
+		frr_each (if_connected, ifc->ifp->connected, connected) {
+			if (connected->address->family != AF_INET6)
+				continue;
+			if (IN6_IS_ADDR_LINKLOCAL(&connected->address->u.prefix6))
+				v6_local = &connected->address->u.prefix6;
+			else
+				v6_global = &connected->address->u.prefix6;
+		}
+
 		/*
 		 * When we are using the v6 global as part of the peering
 		 * nexthops and we are removing it, then we need to
@@ -416,17 +446,17 @@ static int bgp_interface_address_delete(ZAPI_CALLBACK_ARGS)
 		 * we do not want the peering to bounce.
 		 */
 		for (ALL_LIST_ELEMENTS(bgp->peer, node, nnode, peer)) {
-			afi_t afi;
-			safi_t safi;
-
-			if (addr->family == AF_INET)
-				continue;
-
-			if (!IN6_IS_ADDR_LINKLOCAL(&addr->u.prefix6)
-			    && memcmp(&peer->nexthop.v6_global,
-				      &addr->u.prefix6, 16)
-				       == 0) {
-				memset(&peer->nexthop.v6_global, 0, 16);
+			if (IPV6_ADDR_SAME(&peer->nexthop.v6_global,
+					   &addr->u.prefix6)) {
+				if (v6_global)
+					IPV6_ADDR_COPY(&peer->nexthop.v6_global,
+						       v6_global);
+				else if (v6_local)
+					IPV6_ADDR_COPY(&peer->nexthop.v6_global,
+						       v6_local);
+				else
+					memset(&peer->nexthop.v6_global, 0,
+					       IPV6_MAX_BYTELEN);
 				FOREACH_AFI_SAFI (afi, safi)
 					bgp_announce_route(peer, afi, safi,
 							   true);

tests/topotests/bgp_nexthop_mp_ipv4_6/h1/zebra.conf

@@ -0,0 +1,6 @@
+ipv6 route ::/0 fd00:100::2
+ip route 0.0.0.0/0 192.168.1.2
+interface eth-r1
+ ip address 192.168.1.1/24
+ ipv6 address fd00:100::1/64
+!

tests/topotests/bgp_nexthop_mp_ipv4_6/h2/zebra.conf

@@ -0,0 +1,6 @@
+ipv6 route ::/0 fd00:700::2
+ip route 0.0.0.0/0 192.168.7.2
+interface eth-r7
+ ip address 192.168.7.1/24
+ ipv6 address fd00:700::1/64
+!

tests/topotests/bgp_nexthop_mp_ipv4_6/h3/zebra.conf

@@ -0,0 +1,6 @@
+ipv6 route ::/0 fd00:800::2
+ip route 0.0.0.0/0 192.168.8.2
+interface eth-r8
+ ip address 192.168.8.1/24
+ ipv6 address fd00:800::1/64
+!

tests/topotests/bgp_nexthop_mp_ipv4_6/r1/bgp_ipv4.json

@@ -0,0 +1,70 @@
+{
+  "routes": {
+    "192.168.1.0/24": [
+      {
+        "valid": true,
+        "bestpath": true,
+        "path": "",
+        "nexthops": [
+          {
+            "ip": "0.0.0.0",
+            "afi": "ipv4",
+            "used": true
+          }
+        ]
+      }
+    ],
+    "192.168.7.0/24": [
+      {
+        "valid": true,
+        "multipath": true,
+        "path": "65000 65700",
+        "nexthops": [
+          {
+            "ip": "172.16.1.3",
+            "afi": "ipv4",
+            "used": true
+          }
+        ]
+      },
+      {
+        "valid": true,
+        "bestpath": true,
+        "path": "65000 65700",
+        "nexthops": [
+          {
+            "ip": "172.16.0.2",
+            "afi": "ipv4",
+            "used": true
+          }
+        ]
+      }
+    ],
+    "192.168.8.0/24": [
+      {
+        "valid": true,
+        "multipath": true,
+        "path": "65000 65800",
+        "nexthops": [
+          {
+            "ip": "172.16.1.3",
+            "afi": "ipv4",
+            "used": true
+          }
+        ]
+      },
+      {
+        "valid": true,
+        "bestpath": true,
+        "path": "65000 65800",
+        "nexthops": [
+          {
+            "ip": "172.16.0.2",
+            "afi": "ipv4",
+            "used": true
+          }
+        ]
+      }
+    ]
+  }
+}