Fix/revert ipv4 mapped ipv6 stuff 10.1

bgpd/bgp_nht.c

@@ -320,6 +320,11 @@ 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)
@@ -351,9 +356,7 @@ int bgp_find_or_add_nexthop(struct bgp *bgp_route, struct bgp *bgp_nexthop,
 			}
 			return 0;
 		}
-		if (afi == AFI_IP6 && p.family == AF_INET)
-			/* IPv4 mapped IPv6 nexthop address */
-			afi = AFI_IP;
+
 		srte_color = bgp_attr_get_color(pi->attr);
 
 	} else if (peer) {
@@ -1037,11 +1040,19 @@ 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 (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 (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;
+			}
 		}
 		break;
 	case AFI_IP6:
@@ -1057,7 +1068,6 @@ 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 &&
@@ -1072,33 +1082,15 @@ 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)) {
-					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;
-						p->family = AF_INET;
-					} else
-						p->u.prefix6 =
-							pi->attr->mp_nexthop_global;
-				} else
-					p->u.prefix6 =
-						pi->attr->mp_nexthop_local;
-			} 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;
-					p->family = AF_INET;
-				} else
+					       BGP_ATTR_NH_MP_PREFER_GLOBAL))
 					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

@@ -9676,7 +9676,10 @@ void route_vty_out(struct vty *vty, const struct prefix *p,
 				json_object_string_add(json_nexthop_ll, "scope",
 						       "link-local");
 
-				if (!CHECK_FLAG(attr->nh_flags,
+				if ((IPV6_ADDR_CMP(&attr->mp_nexthop_global,
+						   &attr->mp_nexthop_local) !=
+				     0) &&
+				    !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

@@ -508,9 +508,6 @@ struct stream *bpacket_reformat_for_peer(struct bpacket *pkt,
 				gnh_modified = 1;
 			}
 		} else if (IN6_IS_ADDR_UNSPECIFIED(&v6nhglobal)) {
-			/* the UPDATE is originating from the local router.
-			 * Build the global nexthop.
-			 */
 			mod_v6nhg = &peer->nexthop.v6_global;
 			gnh_modified = 1;
 		} else if ((peer->sort == BGP_PEER_EBGP)
@@ -524,32 +521,16 @@ struct stream *bpacket_reformat_for_peer(struct bpacket *pkt,
 			 */
 			mod_v6nhg = &peer->nexthop.v6_global;
 			gnh_modified = 1;
-		} else if (IS_MAPPED_IPV6(&v6nhglobal) &&
-			   !IN6_IS_ADDR_LINKLOCAL(&peer->nexthop.v6_global)) {
-			/* prefer a IPv6 native global address over
-			 * an IPv4-mapped IPv6 address as nexthop when
-			 * forwarding UPDATEs.
-			 */
-			mod_v6nhg = &peer->nexthop.v6_global;
-			gnh_modified = 1;
 		}
 
-		if (peer->nexthop.v4.s_addr != INADDR_ANY &&
-		    (IN6_IS_ADDR_UNSPECIFIED(mod_v6nhg) ||
-		     (IN6_IS_ADDR_LINKLOCAL(mod_v6nhg) &&
-		      ((peer->connection->su.sa.sa_family == AF_INET6 &&
-			paf->afi == AFI_IP) ||
-		       (peer->connection->su.sa.sa_family == AF_INET &&
-			paf->afi == AFI_IP6))))) {
-			ipv4_to_ipv4_mapped_ipv6(mod_v6nhg, peer->nexthop.v4);
-			gnh_modified = 1;
+		if (IN6_IS_ADDR_UNSPECIFIED(mod_v6nhg)) {
+			if (peer->nexthop.v4.s_addr != INADDR_ANY) {
+				ipv4_to_ipv4_mapped_ipv6(mod_v6nhg,
+							 peer->nexthop.v4);
+			}
 		}
 
 		if (IS_MAPPED_IPV6(&peer->nexthop.v6_global)) {
-			/* If the interface to the peer has no global IPv6
-			 * address, replace the nexthop in UPDATE with
-			 * the IPv4-mapped IPv6 address if any.
-			 */
 			mod_v6nhg = &peer->nexthop.v6_global;
 			gnh_modified = 1;
 		}