Merge pull request #6821 from Niral-Networks/niral_6VPE_6PE_fix

BGP : Fix for nexthop as IPv4 mapped IPv6 address
FRRouting · Aug 4, 2020 · c117742 · c117742
2 parents 35b82b0 + 92d6f76
commit c117742
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Showing 6 changed files with 67 additions and 13 deletions.
diff --git a/bgpd/bgp_nht.c b/bgpd/bgp_nht.c
@@ -146,6 +146,11 @@ int bgp_find_or_add_nexthop(struct bgp *bgp_route, struct bgp *bgp_nexthop,
 			afi = BGP_ATTR_NEXTHOP_AFI_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)
@@ -533,6 +538,7 @@ static int make_prefix(int afi, struct bgp_path_info *pi, struct prefix *p)
 				    : 0;
 	struct bgp_dest *net = pi->net;
 	const struct prefix *p_orig = bgp_dest_get_prefix(net);
+	struct in_addr ipv4;
 
 	if (p_orig->family == AF_FLOWSPEC) {
 		if (!pi->peer)
@@ -548,8 +554,15 @@ 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 {
-			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 {
+				p->u.prefix4 = pi->attr->nexthop;
+				p->prefixlen = IPV4_MAX_BITLEN;
+			}
 		}
 		break;
 	case AFI_IP6:

diff --git a/bgpd/bgp_updgrp_packet.c b/bgpd/bgp_updgrp_packet.c
@@ -574,6 +574,18 @@ struct stream *bpacket_reformat_for_peer(struct bpacket *pkt,
 			gnh_modified = 1;
 		}
 
+		if (IN6_IS_ADDR_UNSPECIFIED(mod_v6nhg)) {
+			if (peer->nexthop.v4.s_addr) {
+				ipv4_to_ipv4_mapped_ipv6(mod_v6nhg,
+							 peer->nexthop.v4);
+			}
+		}
+
+		if (IS_MAPPED_IPV6(&peer->nexthop.v6_global)) {
+			mod_v6nhg = &peer->nexthop.v6_global;
+			gnh_modified = 1;
+		}
+
 		if (nhlen == BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL
 		    || nhlen == BGP_ATTR_NHLEN_VPNV6_GLOBAL_AND_LL) {
 			stream_get_from(&v6nhlocal, s, offset_nhlocal,

diff --git a/lib/ipaddr.h b/lib/ipaddr.h
@@ -89,6 +89,13 @@ static inline char *ipaddr2str(const struct ipaddr *ip, char *buf, int size)
 	return buf;
 }
 
+#define IS_MAPPED_IPV6(A)                                                      \
+	((A)->s6_addr32[0] == 0x00000000                                       \
+		 ? ((A)->s6_addr32[1] == 0x00000000                            \
+			    ? (ntohl((A)->s6_addr32[2]) == 0xFFFF ? 1 : 0)     \
+			    : 0)                                               \
+		 : 0)
+
 /*
  * Convert IPv4 address to IPv4-mapped IPv6 address which is of the
  * form ::FFFF:<IPv4 address> (RFC 4291). This IPv6 address can then

diff --git a/zebra/rt_netlink.c b/zebra/rt_netlink.c
@@ -1051,14 +1051,17 @@ static bool _netlink_route_add_gateway_info(uint8_t route_family,
 				 bytelen + 2))
 			return false;
 	} else {
-		if (gw_family == AF_INET) {
-			if (!nl_attr_put(nlmsg, req_size, RTA_GATEWAY,
-					 &nexthop->gate.ipv4, bytelen))
-				return false;
-		} else {
-			if (!nl_attr_put(nlmsg, req_size, RTA_GATEWAY,
-					 &nexthop->gate.ipv6, bytelen))
-				return false;
+		if (!(nexthop->rparent
+		      && IS_MAPPED_IPV6(&nexthop->rparent->gate.ipv6))) {
+			if (gw_family == AF_INET) {
+				if (!nl_attr_put(nlmsg, req_size, RTA_GATEWAY,
+						 &nexthop->gate.ipv4, bytelen))
+					return false;
+			} else {
+				if (!nl_attr_put(nlmsg, req_size, RTA_GATEWAY,
+						 &nexthop->gate.ipv6, bytelen))
+					return false;
+			}
 		}
 	}
 

diff --git a/zebra/zebra_fpm_netlink.c b/zebra/zebra_fpm_netlink.c
@@ -364,6 +364,7 @@ static int netlink_route_info_encode(struct netlink_route_info *ri,
 	struct rtattr *nest, *inner_nest;
 	struct rtnexthop *rtnh;
 	struct vxlan_encap_info_t *vxlan;
+	struct in6_addr ipv6;
 
 	struct {
 		struct nlmsghdr n;
@@ -423,8 +424,15 @@ static int netlink_route_info_encode(struct netlink_route_info *ri,
 		nhi = &ri->nhs[0];
 
 		if (nhi->gateway) {
-			nl_attr_put(&req->n, in_buf_len, RTA_GATEWAY,
-				    nhi->gateway, bytelen);
+			if (nhi->type == NEXTHOP_TYPE_IPV4_IFINDEX
+			    && ri->af == AF_INET6) {
+				ipv4_to_ipv4_mapped_ipv6(&ipv6,
+							 nhi->gateway->ipv4);
+				nl_attr_put(&req->n, in_buf_len, RTA_GATEWAY,
+					    &ipv6, bytelen);
+			} else
+				nl_attr_put(&req->n, in_buf_len, RTA_GATEWAY,
+					    nhi->gateway, bytelen);
 		}
 
 		if (nhi->if_index) {

diff --git a/zebra/zebra_nhg.c b/zebra/zebra_nhg.c
@@ -1775,6 +1775,7 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
 	struct interface *ifp;
 	rib_dest_t *dest;
 	struct zebra_vrf *zvrf;
+	struct in_addr ipv4;
 
 	if ((nexthop->type == NEXTHOP_TYPE_IPV4)
 	    || nexthop->type == NEXTHOP_TYPE_IPV6)
@@ -1835,13 +1836,23 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
 		return 0;
 	}
 
+	/* Validation for ipv4 mapped ipv6 nexthop. */
+	if (IS_MAPPED_IPV6(&nexthop->gate.ipv6)) {
+		afi = AFI_IP;
+	}
+
 	/* Make lookup prefix. */
 	memset(&p, 0, sizeof(struct prefix));
 	switch (afi) {
 	case AFI_IP:
 		p.family = AF_INET;
 		p.prefixlen = IPV4_MAX_PREFIXLEN;
-		p.u.prefix4 = nexthop->gate.ipv4;
+		if (IS_MAPPED_IPV6(&nexthop->gate.ipv6)) {
+			ipv4_mapped_ipv6_to_ipv4(&nexthop->gate.ipv6, &ipv4);
+			p.u.prefix4 = ipv4;
+		} else {
+			p.u.prefix4 = nexthop->gate.ipv4;
+		}
 		break;
 	case AFI_IP6:
 		p.family = AF_INET6;