bgpd, tests: set ipv4-mapped ipv6 for ipv4 on ipv6

The code was expected that no IPv6 global address was present but the previous commit was replacing nexthop.v6global by the link-local address instead of un-setting it in case of removal of the IPv6 global. Set also ipv4-mapped ipv6 address as nexthop when a link-local is found and it is an ipv4 prefix over ipv6 nexthop. Signed-off-by: Louis Scalbert <[email protected]>
FRRouting · Oct 17, 2024 · adcd6cb · adcd6cb
1 parent 2315e7d
commit adcd6cb
Show file tree

Hide file tree

Showing 2 changed files with 15 additions and 9 deletions.
diff --git a/bgpd/bgp_updgrp_packet.c b/bgpd/bgp_updgrp_packet.c
@@ -523,11 +523,13 @@ 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 != INADDR_ANY) {
-				ipv4_to_ipv4_mapped_ipv6(mod_v6nhg,
-							 peer->nexthop.v4);
-			}
+		if (!peer->conf_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 (IS_MAPPED_IPV6(&peer->nexthop.v6_global)) {

diff --git a/tests/topotests/bgp_ipv4_over_ipv6/test_rfc5549_ebgp_unnumbered_nbr.py b/tests/topotests/bgp_ipv4_over_ipv6/test_rfc5549_ebgp_unnumbered_nbr.py
@@ -670,10 +670,15 @@ def bgp_prefix_received_v4_mapped_v6_nh(router):
                 {
                     "nexthops": [
                         {
-                            "ip": "::ffff:10.0.5.1",
                             "hostname": "r1",
                             "afi": "ipv6",
                             "scope": "global",
+                        },
+                        {
+                            "hostname": "r1",
+                            "afi": "ipv6",
+                            "scope": "link-local",
+                            "used": True,
                         }
                     ]
                 }
@@ -748,13 +753,12 @@ def bgp_prefix_received_v4_mapped_v6_nh(router):
         !
         """
     )
-    # verify that r1 has rcvd the prefix with v4-mapped-v6 address as the nexthop
+    # verify that r1 has rcvd the prefix with a link-local as the nexthop
     test_func = functools.partial(bgp_prefix_received_v4_mapped_v6_nh, r2)
     _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
     assert (
         result is None
-    ), "Testcase {} : Failed \n Error: Nexthop for prefix 11.0.20.1 \
-    is not ::ffff:10.0.5.1".format(
+    ), "Testcase {} : Failed \n Error: Nexthop for prefix 11.0.20.1 is not the link-local address.".format(
         tc_name
     )