From 0d2d20825e91fddb856fd34103f72a5485e04e49 Mon Sep 17 00:00:00 2001
From: Jafar Al-Gharaibeh <jafar@atcorp.com>
Date: Wed, 21 Aug 2024 13:26:50 -0500
Subject: [PATCH] Revert "Merge pull request #16439 from
 louis-6wind/fix-ipv4-mapped-ipv6"

This reverts commit cc0fdd3b1d1b3554896fc03eec16379b7bae2b40, reversing
changes made to 4e208087fd854e3e1528519745447f69691b04ad.
---
 bgpd/bgp_nht.c                                | 19 +++--------------
 bgpd/bgp_updgrp_packet.c                      | 21 ++-----------------
 .../r2/bgp_ipv6_step2.json                    |  5 -----
 .../r3/bgp_ipv6_step2.json                    |  5 -----
 4 files changed, 5 insertions(+), 45 deletions(-)

diff --git a/bgpd/bgp_nht.c b/bgpd/bgp_nht.c
index 8da7521ffc..504428b0d6 100644
--- a/bgpd/bgp_nht.c
+++ b/bgpd/bgp_nht.c
@@ -351,9 +351,7 @@ 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) {
@@ -1080,25 +1078,14 @@ static int make_prefix(int afi, struct bgp_path_info *pi, struct prefix *p)
 							&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
-					p->u.prefix6 =
-						pi->attr->mp_nexthop_global;
-			}
+			} else
+				p->u.prefix6 = pi->attr->mp_nexthop_global;
 		}
 		break;
 	default:
diff --git a/bgpd/bgp_updgrp_packet.c b/bgpd/bgp_updgrp_packet.c
index 0f47388389..b7d5f66450 100644
--- a/bgpd/bgp_updgrp_packet.c
+++ b/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 +521,18 @@ 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))))) {
+		      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;
 		}
 
 		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;
 		}
diff --git a/tests/topotests/bgp_nexthop_mp_ipv4_6/r2/bgp_ipv6_step2.json b/tests/topotests/bgp_nexthop_mp_ipv4_6/r2/bgp_ipv6_step2.json
index 6738d45750..21f36089b6 100644
--- a/tests/topotests/bgp_nexthop_mp_ipv4_6/r2/bgp_ipv6_step2.json
+++ b/tests/topotests/bgp_nexthop_mp_ipv4_6/r2/bgp_ipv6_step2.json
@@ -6,11 +6,6 @@
         "bestpath": true,
         "path": "65100",
         "nexthops": [
-          {
-            "ip": "::ffff:ac10:1",
-            "afi": "ipv6",
-            "scope": "global"
-          },
           {
             "afi": "ipv6",
             "scope": "link-local",
diff --git a/tests/topotests/bgp_nexthop_mp_ipv4_6/r3/bgp_ipv6_step2.json b/tests/topotests/bgp_nexthop_mp_ipv4_6/r3/bgp_ipv6_step2.json
index 807806ff8d..21f36089b6 100644
--- a/tests/topotests/bgp_nexthop_mp_ipv4_6/r3/bgp_ipv6_step2.json
+++ b/tests/topotests/bgp_nexthop_mp_ipv4_6/r3/bgp_ipv6_step2.json
@@ -6,11 +6,6 @@
         "bestpath": true,
         "path": "65100",
         "nexthops": [
-          {
-            "ip": "::ffff:ac10:101",
-            "afi": "ipv6",
-            "scope": "global"
-          },
           {
             "afi": "ipv6",
             "scope": "link-local",