Merge pull request #13728 from opensourcerouting/fix/addpath_drop_non_best_addpaths

bgpd: Implement neighbor X addpath-tx-best-selected command

27 files changed, 478 insertions, 36 deletions

diff --git a/bgpd/bgp_addpath.c b/bgpd/bgp_addpath.c
index 7f746541ff..de4b4a48af 100644
--- a/bgpd/bgp_addpath.c
+++ b/bgpd/bgp_addpath.c
@@ -25,7 +25,14 @@ static const struct bgp_addpath_strategy_names strat_names[BGP_ADDPATH_MAX] = {
 		.human_description = "Advertise bestpath per AS via addpath",
 		.type_json_name = "addpathTxBestpathPerAS",
 		.id_json_name = "addpathTxIdBestPerAS"
-	}
+	},
+	{
+		.config_name = "addpath-tx-best-selected",
+		.human_name = "Best-Selected",
+		.human_description = "Advertise best N selected paths via addpath",
+		.type_json_name = "addpathTxBestSelectedPaths",
+		.id_json_name = "addpathTxIdBestSelected"
+	},
 };
 
 static const struct bgp_addpath_strategy_names unknown_names = {
@@ -161,6 +168,8 @@ bool bgp_addpath_tx_path(enum bgp_addpath_strat strat, struct bgp_path_info *pi)
 			return true;
 		else
 			return false;
+	case BGP_ADDPATH_BEST_SELECTED:
+		return true;
 	case BGP_ADDPATH_MAX:
 		return false;
 	}
@@ -356,7 +365,8 @@ void bgp_addpath_type_changed(struct bgp *bgp)
  * change take effect.
  */
 void bgp_addpath_set_peer_type(struct peer *peer, afi_t afi, safi_t safi,
-			      enum bgp_addpath_strat addpath_type)
+			       enum bgp_addpath_strat addpath_type,
+			       uint8_t paths)
 {
 	struct bgp *bgp = peer->bgp;
 	enum bgp_addpath_strat old_type;
@@ -367,6 +377,8 @@ void bgp_addpath_set_peer_type(struct peer *peer, afi_t afi, safi_t safi,
 	if (safi == SAFI_LABELED_UNICAST)
 		safi = SAFI_UNICAST;
 
+	peer->addpath_best_selected[afi][safi] = paths;
+
 	old_type = peer->addpath_type[afi][safi];
 	if (addpath_type == old_type)
 		return;
@@ -411,10 +423,9 @@ void bgp_addpath_set_peer_type(struct peer *peer, afi_t afi, safi_t safi,
 			     tmp_peer)) {
 				if (tmp_peer->addpath_type[afi][safi] ==
 				    old_type) {
-					bgp_addpath_set_peer_type(tmp_peer,
-								 afi,
-								 safi,
-								 addpath_type);
+					bgp_addpath_set_peer_type(
+						tmp_peer, afi, safi,
+						addpath_type, paths);
 				}
 			}
 		}
diff --git a/bgpd/bgp_addpath.h b/bgpd/bgp_addpath.h
index 909a9710c4..2b91d450bc 100644
--- a/bgpd/bgp_addpath.h
+++ b/bgpd/bgp_addpath.h
@@ -50,7 +50,8 @@ bool bgp_addpath_tx_path(enum bgp_addpath_strat strat,
  * Change the type of addpath used for a peer.
  */
 void bgp_addpath_set_peer_type(struct peer *peer, afi_t afi, safi_t safi,
-			      enum bgp_addpath_strat addpath_type);
+			       enum bgp_addpath_strat addpath_type,
+			       uint8_t paths);
 
 void bgp_addpath_update_ids(struct bgp *bgp, struct bgp_dest *dest, afi_t afi,
 			    safi_t safi);
diff --git a/bgpd/bgp_addpath_types.h b/bgpd/bgp_addpath_types.h
index 3de9546a6d..8e32b0444a 100644
--- a/bgpd/bgp_addpath_types.h
+++ b/bgpd/bgp_addpath_types.h
@@ -12,6 +12,7 @@
 enum bgp_addpath_strat {
 	BGP_ADDPATH_ALL = 0,
 	BGP_ADDPATH_BEST_PER_AS,
+	BGP_ADDPATH_BEST_SELECTED,
 	BGP_ADDPATH_MAX,
 	BGP_ADDPATH_NONE,
 };
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index 35b8223644..0b821acfae 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -579,11 +579,11 @@ struct bgp_path_info *bgp_get_imported_bpi_ultimate(struct bgp_path_info *info)
 
 /* Compare two bgp route entity.  If 'new' is preferable over 'exist' return 1.
  */
-static int bgp_path_info_cmp(struct bgp *bgp, struct bgp_path_info *new,
-			     struct bgp_path_info *exist, int *paths_eq,
-			     struct bgp_maxpaths_cfg *mpath_cfg, int debug,
-			     char *pfx_buf, afi_t afi, safi_t safi,
-			     enum bgp_path_selection_reason *reason)
+int bgp_path_info_cmp(struct bgp *bgp, struct bgp_path_info *new,
+		      struct bgp_path_info *exist, int *paths_eq,
+		      struct bgp_maxpaths_cfg *mpath_cfg, int debug,
+		      char *pfx_buf, afi_t afi, safi_t safi,
+		      enum bgp_path_selection_reason *reason)
 {
 	const struct prefix *new_p;
 	struct attr *newattr, *existattr;
diff --git a/bgpd/bgp_route.h b/bgpd/bgp_route.h
index d4837d3f53..ccfd9d00d8 100644
--- a/bgpd/bgp_route.h
+++ b/bgpd/bgp_route.h
@@ -910,6 +910,11 @@ extern void bgp_path_info_add_with_caller(const char *caller,
 					  struct bgp_dest *dest,
 					  struct bgp_path_info *pi);
 extern void bgp_aggregate_free(struct bgp_aggregate *aggregate);
+extern int bgp_path_info_cmp(struct bgp *bgp, struct bgp_path_info *new,
+			     struct bgp_path_info *exist, int *paths_eq,
+			     struct bgp_maxpaths_cfg *mpath_cfg, int debug,
+			     char *pfx_buf, afi_t afi, safi_t safi,
+			     enum bgp_path_selection_reason *reason);
 #define bgp_path_info_add(A, B)                                                \
 	bgp_path_info_add_with_caller(__func__, (A), (B))
 #define bgp_path_info_free(B) bgp_path_info_free_with_caller(__func__, (B))
diff --git a/bgpd/bgp_updgrp.c b/bgpd/bgp_updgrp.c
index a642be935d..0fe6180bea 100644
--- a/bgpd/bgp_updgrp.c
+++ b/bgpd/bgp_updgrp.c
@@ -142,6 +142,8 @@ static void conf_copy(struct peer *dst, struct peer *src, afi_t afi,
 	dst->afc_nego[afi][safi] = src->afc_nego[afi][safi];
 	dst->orf_plist[afi][safi] = src->orf_plist[afi][safi];
 	dst->addpath_type[afi][safi] = src->addpath_type[afi][safi];
+	dst->addpath_best_selected[afi][safi] =
+		src->addpath_best_selected[afi][safi];
 	dst->local_as = src->local_as;
 	dst->change_local_as = src->change_local_as;
 	dst->shared_network = src->shared_network;
@@ -307,6 +309,7 @@ static void *updgrp_hash_alloc(void *p)
  *       16. Local-as should match, if configured.
  *       17. maximum-prefix-out
  *       18. Local-role should also match, if configured.
+ *       19. Add-Path best selected paths count should match as well
  *      )
  */
 static unsigned int updgrp_hash_key_make(const void *p)
@@ -340,6 +343,7 @@ static unsigned int updgrp_hash_key_make(const void *p)
 	key = jhash_1word((peer->flags & PEER_UPDGRP_FLAGS), key);
 	key = jhash_1word((flags & PEER_UPDGRP_AF_FLAGS), key);
 	key = jhash_1word((uint32_t)peer->addpath_type[afi][safi], key);
+	key = jhash_1word(peer->addpath_best_selected[afi][safi], key);
 	key = jhash_1word((peer->cap & PEER_UPDGRP_CAP_FLAGS), key);
 	key = jhash_1word((peer->af_cap[afi][safi] & PEER_UPDGRP_AF_CAP_FLAGS),
 			  key);
diff --git a/bgpd/bgp_updgrp_adv.c b/bgpd/bgp_updgrp_adv.c
index b412fa6b20..68fd11a042 100644
--- a/bgpd/bgp_updgrp_adv.c
+++ b/bgpd/bgp_updgrp_adv.c
@@ -87,6 +87,67 @@ static void adj_free(struct bgp_adj_out *adj)
 	XFREE(MTYPE_BGP_ADJ_OUT, adj);
 }
 
+static void
+subgrp_announce_addpath_best_selected(struct bgp_dest *dest,
+				      struct update_subgroup *subgrp)
+{
+	afi_t afi = SUBGRP_AFI(subgrp);
+	safi_t safi = SUBGRP_SAFI(subgrp);
+	struct peer *peer = SUBGRP_PEER(subgrp);
+	enum bgp_path_selection_reason reason;
+	char pfx_buf[PREFIX2STR_BUFFER] = {};
+	int paths_eq = 0;
+	int best_path_count = 0;
+	struct list *list = list_new();
+	struct bgp_path_info *pi = NULL;
+
+	if (peer->addpath_type[afi][safi] == BGP_ADDPATH_BEST_SELECTED) {
+		while (best_path_count++ <
+		       peer->addpath_best_selected[afi][safi]) {
+			struct bgp_path_info *exist = NULL;
+
+			for (pi = bgp_dest_get_bgp_path_info(dest); pi;
+			     pi = pi->next) {
+				if (listnode_lookup(list, pi))
+					continue;
+
+				if (CHECK_FLAG(pi->flags, BGP_PATH_SELECTED))
+					continue;
+
+				if (bgp_path_info_cmp(peer->bgp, pi, exist,
+						      &paths_eq, NULL, 0,
+						      pfx_buf, afi, safi,
+						      &reason))
+					exist = pi;
+			}
+
+			if (exist)
+				listnode_add(list, exist);
+		}
+	}
+
+	for (pi = bgp_dest_get_bgp_path_info(dest); pi; pi = pi->next) {
+		uint32_t id = bgp_addpath_id_for_peer(peer, afi, safi,
+						      &pi->tx_addpath);
+
+		if (peer->addpath_type[afi][safi] ==
+		    BGP_ADDPATH_BEST_SELECTED) {
+			if (listnode_lookup(list, pi))
+				subgroup_process_announce_selected(
+					subgrp, pi, dest, afi, safi, id);
+			else
+				subgroup_process_announce_selected(
+					subgrp, NULL, dest, afi, safi, id);
+		} else {
+			subgroup_process_announce_selected(subgrp, pi, dest,
+							   afi, safi, id);
+		}
+	}
+
+	if (list)
+		list_delete(&list);
+}
+
 static void subgrp_withdraw_stale_addpath(struct updwalk_context *ctx,
 					  struct update_subgroup *subgrp)
 {
@@ -125,7 +186,6 @@ static int group_announce_route_walkcb(struct update_group *updgrp, void *arg)
 {
 	struct updwalk_context *ctx = arg;
 	struct update_subgroup *subgrp;
-	struct bgp_path_info *pi;
 	afi_t afi;
 	safi_t safi;
 	struct peer *peer;
@@ -143,7 +203,6 @@ static int group_announce_route_walkcb(struct update_group *updgrp, void *arg)
 			   bgp_dest_to_rnode(ctx->dest));
 
 	UPDGRP_FOREACH_SUBGRP (updgrp, subgrp) {
-
 		/*
 		 * Skip the subgroups that have coalesce timer running. We will
 		 * walk the entire prefix table for those subgroups when the
@@ -155,19 +214,8 @@ static int group_announce_route_walkcb(struct update_group *updgrp, void *arg)
 			if (addpath_capable) {
 				subgrp_withdraw_stale_addpath(ctx, subgrp);
 
-				for (pi = bgp_dest_get_bgp_path_info(ctx->dest);
-				     pi; pi = pi->next) {
-					/* Skip the bestpath for now */
-					if (pi == ctx->pi)
-						continue;
-
-					subgroup_process_announce_selected(
-						subgrp, pi, ctx->dest, afi,
-						safi,
-						bgp_addpath_id_for_peer(
-							peer, afi, safi,
-							&pi->tx_addpath));
-				}
+				subgrp_announce_addpath_best_selected(ctx->dest,
+								      subgrp);
 
 				/* Process the bestpath last so the "show [ip]
 				 * bgp neighbor x.x.x.x advertised"
@@ -689,6 +737,10 @@ void subgroup_announce_table(struct update_subgroup *subgrp,
 	SET_FLAG(subgrp->sflags, SUBGRP_STATUS_TABLE_REPARSING);
 
 	for (dest = bgp_table_top(table); dest; dest = bgp_route_next(dest)) {
+
+		if (addpath_capable)
+			subgrp_announce_addpath_best_selected(dest, subgrp);
+
 		for (ri = bgp_dest_get_bgp_path_info(dest); ri; ri = ri->next) {
 
 			if (!bgp_check_selected(ri, peer, addpath_capable, afi,
@@ -706,10 +758,12 @@ void subgroup_announce_table(struct update_subgroup *subgrp,
 			    is_default_prefix(bgp_dest_get_prefix(dest)))
 				break;
 
-			subgroup_process_announce_selected(
-				subgrp, ri, dest, afi, safi_rib,
-				bgp_addpath_id_for_peer(peer, afi, safi_rib,
-							&ri->tx_addpath));
+			if (CHECK_FLAG(ri->flags, BGP_PATH_SELECTED))
+				subgroup_process_announce_selected(
+					subgrp, ri, dest, afi, safi_rib,
+					bgp_addpath_id_for_peer(
+						peer, afi, safi_rib,
+						&ri->tx_addpath));
 		}
 	}
 	UNSET_FLAG(subgrp->sflags, SUBGRP_STATUS_TABLE_REPARSING);
diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index 66fb7ae77a..d03398c802 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -8803,7 +8803,7 @@ DEFUN (neighbor_addpath_tx_all_paths,
 		return CMD_WARNING_CONFIG_FAILED;
 
 	bgp_addpath_set_peer_type(peer, bgp_node_afi(vty), bgp_node_safi(vty),
-				 BGP_ADDPATH_ALL);
+				  BGP_ADDPATH_ALL, 0);
 	return CMD_SUCCESS;
 }
 
@@ -8836,7 +8836,7 @@ DEFUN (no_neighbor_addpath_tx_all_paths,
 	}
 
 	bgp_addpath_set_peer_type(peer, bgp_node_afi(vty), bgp_node_safi(vty),
-				 BGP_ADDPATH_NONE);
+				  BGP_ADDPATH_NONE, 0);
 
 	return CMD_SUCCESS;
 }
@@ -8847,6 +8847,45 @@ ALIAS_HIDDEN(no_neighbor_addpath_tx_all_paths,
 	     NO_STR NEIGHBOR_STR NEIGHBOR_ADDR_STR2
 	     "Use addpath to advertise all paths to a neighbor\n")
 
+DEFPY (neighbor_addpath_tx_best_selected_paths,
+       neighbor_addpath_tx_best_selected_paths_cmd,
+       "neighbor <A.B.C.D|X:X::X:X|WORD>$neighbor addpath-tx-best-selected (1-6)$paths",
+       NEIGHBOR_STR
+       NEIGHBOR_ADDR_STR2
+       "Use addpath to advertise best selected paths to a neighbor\n"
+       "The number of best paths\n")
+{
+	struct peer *peer;
+
+	peer = peer_and_group_lookup_vty(vty, neighbor);
+	if (!peer)
+		return CMD_WARNING_CONFIG_FAILED;
+
+	bgp_addpath_set_peer_type(peer, bgp_node_afi(vty), bgp_node_safi(vty),
+				  BGP_ADDPATH_BEST_SELECTED, paths);
+	return CMD_SUCCESS;
+}
+
+DEFPY (no_neighbor_addpath_tx_best_selected_paths,
+       no_neighbor_addpath_tx_best_selected_paths_cmd,
+       "no neighbor <A.B.C.D|X:X::X:X|WORD>$neighbor addpath-tx-best-selected [(1-6)]",
+       NO_STR
+       NEIGHBOR_STR
+       NEIGHBOR_ADDR_STR2
+       "Use addpath to advertise best selected paths to a neighbor\n"
+       "The number of best paths\n")
+{
+	struct peer *peer;
+
+	peer = peer_and_group_lookup_vty(vty, neighbor);
+	if (!peer)
+		return CMD_WARNING_CONFIG_FAILED;
+
+	bgp_addpath_set_peer_type(peer, bgp_node_afi(vty), bgp_node_safi(vty),
+				  BGP_ADDPATH_BEST_SELECTED, 0);
+	return CMD_SUCCESS;
+}
+
 DEFUN (neighbor_addpath_tx_bestpath_per_as,
        neighbor_addpath_tx_bestpath_per_as_cmd,
        "neighbor <A.B.C.D|X:X::X:X|WORD> addpath-tx-bestpath-per-AS",
@@ -8862,7 +8901,7 @@ DEFUN (neighbor_addpath_tx_bestpath_per_as,
 		return CMD_WARNING_CONFIG_FAILED;
 
 	bgp_addpath_set_peer_type(peer, bgp_node_afi(vty), bgp_node_safi(vty),
-				 BGP_ADDPATH_BEST_PER_AS);
+				  BGP_ADDPATH_BEST_PER_AS, 0);
 
 	return CMD_SUCCESS;
 }
@@ -8896,7 +8935,7 @@ DEFUN (no_neighbor_addpath_tx_bestpath_per_as,
 	}
 
 	bgp_addpath_set_peer_type(peer, bgp_node_afi(vty), bgp_node_safi(vty),
-				 BGP_ADDPATH_NONE);
+				  BGP_ADDPATH_NONE, 0);
 
 	return CMD_SUCCESS;
 }
@@ -17942,6 +17981,13 @@ static void bgp_config_write_peer_af(struct vty *vty, struct bgp *bgp,
 				"  neighbor %s addpath-tx-bestpath-per-AS\n",
 				addr);
 			break;
+		case BGP_ADDPATH_BEST_SELECTED:
+			if (peer->addpath_best_selected[afi][safi])
+				vty_out(vty,
+					"  neighbor %s addpath-tx-best-selected %u\n",
+					addr,
+					peer->addpath_best_selected[afi][safi]);
+			break;
 		case BGP_ADDPATH_MAX:
 		case BGP_ADDPATH_NONE:
 			break;
@@ -19987,6 +20033,40 @@ void bgp_vty_init(void)
 	install_element(BGP_VPNV6_NODE, &neighbor_addpath_tx_all_paths_cmd);
 	install_element(BGP_VPNV6_NODE, &no_neighbor_addpath_tx_all_paths_cmd);
 
+	/* "neighbor addpath-tx-best-selected" commands.*/
+	install_element(BGP_IPV4_NODE,
+			&neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV4_NODE,
+			&no_neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV4M_NODE,
+			&neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV4M_NODE,
+			&no_neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV4L_NODE,
+			&neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV4L_NODE,
+			&no_neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV6_NODE,
+			&neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV6_NODE,
+			&no_neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV6M_NODE,
+			&neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV6M_NODE,
+			&no_neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV6L_NODE,
+			&neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_IPV6L_NODE,
+			&no_neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_VPNV4_NODE,
+			&neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_VPNV4_NODE,
+			&no_neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_VPNV6_NODE,
+			&neighbor_addpath_tx_best_selected_paths_cmd);
+	install_element(BGP_VPNV6_NODE,
+			&no_neighbor_addpath_tx_best_selected_paths_cmd);
+
 	/* "neighbor addpath-tx-bestpath-per-AS" commands.*/
 	install_element(BGP_NODE,
 			&neighbor_addpath_tx_bestpath_per_as_hidden_cmd);
diff --git a/bgpd/bgpd.c b/bgpd/bgpd.c
index 6a8e194298..27d9c49efb 100644
--- a/bgpd/bgpd.c
+++ b/bgpd/bgpd.c
@@ -1182,7 +1182,7 @@ static void peer_free(struct peer *peer)
 		bgp_peer_remove_bfd_config(peer);
 
 	FOREACH_AFI_SAFI (afi, safi)
-		bgp_addpath_set_peer_type(peer, afi, safi, BGP_ADDPATH_NONE);
+		bgp_addpath_set_peer_type(peer, afi, safi, BGP_ADDPATH_NONE, 0);
 
 	if (peer->change_local_as_pretty)
 		XFREE(MTYPE_BGP, peer->change_local_as_pretty);
@@ -1397,6 +1397,7 @@ struct peer *peer_new(struct bgp *bgp)
 		SET_FLAG(peer->af_flags_invert[afi][safi],
 			 PEER_FLAG_SEND_LARGE_COMMUNITY);
 		peer->addpath_type[afi][safi] = BGP_ADDPATH_NONE;
+		peer->addpath_best_selected[afi][safi] = 0;
 		peer->soo[afi][safi] = NULL;
 	}
 
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index 658bb5a58e..95bc07d167 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -1799,6 +1799,9 @@ struct peer {
 #define BGP_MAX_SOFT_VERSION 64
 	char *soft_version;
 
+	/* Add-Path Best selected paths number to advertise */
+	uint8_t addpath_best_selected[AFI_MAX][SAFI_MAX];
+
 	QOBJ_FIELDS;
 };
 DECLARE_QOBJ_TYPE(peer);
diff --git a/doc/user/bgp.rst b/doc/user/bgp.rst
index 29d437b396..ff8ff5a96c 100644
--- a/doc/user/bgp.rst
+++ b/doc/user/bgp.rst
@@ -1669,6 +1669,10 @@ Configuring Peers
    Configure BGP to send best known paths to neighbor in order to preserve multi
    path capabilities inside a network.
 
+.. clicmd:: neighbor <A.B.C.D|X:X::X:X|WORD> addpath-tx-best-selected (1-6)
+
+   Configure BGP to calculate and send N best known paths to the neighbor.
+
 .. clicmd:: neighbor <A.B.C.D|X:X::X:X|WORD> disable-addpath-rx
 
    Do not accept additional paths from this neighbor.
diff --git a/tests/topotests/bgp_addpath_best_selected/__init__.py b/tests/topotests/bgp_addpath_best_selected/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/__init__.py
diff --git a/tests/topotests/bgp_addpath_best_selected/r1/bgpd.conf b/tests/topotests/bgp_addpath_best_selected/r1/bgpd.conf
new file mode 100644
index 0000000000..ba10f7bcc0
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r1/bgpd.conf
@@ -0,0 +1,7 @@
+!
+router bgp 65001
+ timers bgp 3 10
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.2 remote-as external
+ neighbor 192.168.1.2 timers connect 5
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r1/zebra.conf b/tests/topotests/bgp_addpath_best_selected/r1/zebra.conf
new file mode 100644
index 0000000000..b29940f46a
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r1/zebra.conf
@@ -0,0 +1,4 @@
+!
+int r1-eth0
+ ip address 192.168.1.1/24
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r2/bgpd.conf b/tests/topotests/bgp_addpath_best_selected/r2/bgpd.conf
new file mode 100644
index 0000000000..0c13824323
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r2/bgpd.conf
@@ -0,0 +1,28 @@
+router bgp 65002
+ timers bgp 3 10
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.1 remote-as external
+ neighbor 192.168.1.1 remote-as external
+ neighbor 192.168.7.7 remote-as external
+ neighbor 192.168.7.7 timers connect 5
+ neighbor 192.168.2.3 remote-as external
+ neighbor 192.168.2.3 timers connect 5
+ neighbor 192.168.2.3 weight 3
+ neighbor 192.168.2.4 remote-as external
+ neighbor 192.168.2.4 timers connect 5
+ neighbor 192.168.2.4 weight 4
+ neighbor 192.168.2.5 remote-as external
+ neighbor 192.168.2.5 timers connect 5
+ neighbor 192.168.2.5 weight 5
+ neighbor 192.168.2.6 remote-as external
+ neighbor 192.168.2.6 timers connect 5
+ neighbor 192.168.2.6 weight 6
+ address-family ipv4 unicast
+  neighbor 192.168.1.1 addpath-tx-best-selected 1
+  neighbor 192.168.1.1 prefix-list announce out
+  neighbor 192.168.7.7 addpath-tx-best-selected 2
+  neighbor 192.168.7.7 prefix-list announce out
+ exit-address-family
+!
+ip prefix-list announce seq 5 permit 172.16.16.254/32
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r2/zebra.conf b/tests/topotests/bgp_addpath_best_selected/r2/zebra.conf
new file mode 100644
index 0000000000..90587d25d4
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r2/zebra.conf
@@ -0,0 +1,10 @@
+!
+int r2-eth0
+ ip address 192.168.1.2/24
+!
+int r2-eth1
+ ip address 192.168.2.2/24
+!
+int r2-eth2
+ ip address 192.168.7.2/24
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r3/bgpd.conf b/tests/topotests/bgp_addpath_best_selected/r3/bgpd.conf
new file mode 100644
index 0000000000..98eb2e1711
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r3/bgpd.conf
@@ -0,0 +1,9 @@
+router bgp 65003
+ timers bgp 3 10
+ no bgp ebgp-requires-policy
+ neighbor 192.168.2.2 remote-as external
+ neighbor 192.168.2.2 timers connect 5
+ address-family ipv4 unicast
+  redistribute connected
+ exit-address-family
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r3/zebra.conf b/tests/topotests/bgp_addpath_best_selected/r3/zebra.conf
new file mode 100644
index 0000000000..417a4844a5
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r3/zebra.conf
@@ -0,0 +1,7 @@
+!
+int lo
+ ip address 172.16.16.254/32
+!
+int r3-eth0
+ ip address 192.168.2.3/24
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r4/bgpd.conf b/tests/topotests/bgp_addpath_best_selected/r4/bgpd.conf
new file mode 100644
index 0000000000..68245c4a21
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r4/bgpd.conf
@@ -0,0 +1,9 @@
+router bgp 65004
+ timers bgp 3 10
+ no bgp ebgp-requires-policy
+ neighbor 192.168.2.2 remote-as external
+ neighbor 192.168.2.2 timers connect 5
+ address-family ipv4 unicast
+  redistribute connected
+ exit-address-family
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r4/zebra.conf b/tests/topotests/bgp_addpath_best_selected/r4/zebra.conf
new file mode 100644
index 0000000000..241e38693c
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r4/zebra.conf
@@ -0,0 +1,7 @@
+!
+int lo
+ ip address 172.16.16.254/32
+!
+int r4-eth0
+ ip address 192.168.2.4/24
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r5/bgpd.conf b/tests/topotests/bgp_addpath_best_selected/r5/bgpd.conf
new file mode 100644
index 0000000000..0396cc07b4
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r5/bgpd.conf
@@ -0,0 +1,9 @@
+router bgp 65005
+ timers 3 10
+ no bgp ebgp-requires-policy
+ neighbor 192.168.2.2 remote-as external
+ neighbor 192.168.2.2 timers connect 5
+ address-family ipv4 unicast
+  redistribute connected
+ exit-address-family
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r5/zebra.conf b/tests/topotests/bgp_addpath_best_selected/r5/zebra.conf
new file mode 100644
index 0000000000..203d229f27
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r5/zebra.conf
@@ -0,0 +1,7 @@
+!
+int lo
+ ip address 172.16.16.254/32
+!
+int r5-eth0
+ ip address 192.168.2.5/24
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r6/bgpd.conf b/tests/topotests/bgp_addpath_best_selected/r6/bgpd.conf
new file mode 100644
index 0000000000..d9e77b66d6
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r6/bgpd.conf
@@ -0,0 +1,9 @@
+router bgp 65006
+ timers 3 10
+ no bgp ebgp-requires-policy
+ neighbor 192.168.2.2 remote-as external
+ neighbor 192.168.2.2 timers connect 5
+ address-family ipv4 unicast
+  redistribute connected
+ exit-address-family
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r6/zebra.conf b/tests/topotests/bgp_addpath_best_selected/r6/zebra.conf
new file mode 100644
index 0000000000..894dd30579
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r6/zebra.conf
@@ -0,0 +1,7 @@
+!
+int lo
+ ip address 172.16.16.254/32
+!
+int r6-eth0
+ ip address 192.168.2.6/24
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r7/bgpd.conf b/tests/topotests/bgp_addpath_best_selected/r7/bgpd.conf
new file mode 100644
index 0000000000..090846a458
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r7/bgpd.conf
@@ -0,0 +1,7 @@
+!
+router bgp 65007
+ timers bgp 3 10
+ no bgp ebgp-requires-policy
+ neighbor 192.168.7.2 remote-as external
+ neighbor 192.168.7.2 timers connect 5
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/r7/zebra.conf b/tests/topotests/bgp_addpath_best_selected/r7/zebra.conf
new file mode 100644
index 0000000000..55c70bab8b
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/r7/zebra.conf
@@ -0,0 +1,4 @@
+!
+int r7-eth0
+ ip address 192.168.7.7/24
+!
diff --git a/tests/topotests/bgp_addpath_best_selected/test_bgp_addpath_best_selected.py b/tests/topotests/bgp_addpath_best_selected/test_bgp_addpath_best_selected.py
new file mode 100644
index 0000000000..dfd538f1c6
--- /dev/null
+++ b/tests/topotests/bgp_addpath_best_selected/test_bgp_addpath_best_selected.py
@@ -0,0 +1,154 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: ISC
+
+# Copyright (c) 2023 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+
+"""
+Test if Add-Path best selected paths are announced per neighbor.
+"""
+
+import os
+import sys
+import json
+import pytest
+import functools
+
+CWD = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(CWD, "../"))
+
+# pylint: disable=C0413
+from lib import topotest
+from lib.topogen import Topogen, TopoRouter, get_topogen
+
+pytestmark = [pytest.mark.bgpd]
+
+
+def build_topo(tgen):
+    for routern in range(1, 8):
+        tgen.add_router("r{}".format(routern))
+
+    switch = tgen.add_switch("s1")
+    switch.add_link(tgen.gears["r1"])
+    switch.add_link(tgen.gears["r2"])
+
+    switch = tgen.add_switch("s2")
+    switch.add_link(tgen.gears["r2"])
+    switch.add_link(tgen.gears["r3"])
+    switch.add_link(tgen.gears["r4"])
+    switch.add_link(tgen.gears["r5"])
+    switch.add_link(tgen.gears["r6"])
+
+    switch = tgen.add_switch("s3")
+    switch.add_link(tgen.gears["r7"])
+    switch.add_link(tgen.gears["r2"])
+
+
+def setup_module(mod):
+    tgen = Topogen(build_topo, mod.__name__)
+    tgen.start_topology()
+
+    router_list = tgen.routers()
+
+    for i, (rname, router) in enumerate(router_list.items(), 1):
+        router.load_config(
+            TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
+        )
+        router.load_config(
+            TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
+        )
+
+    tgen.start_router()
+
+
+def teardown_module(mod):
+    tgen = get_topogen()
+    tgen.stop_topology()
+
+
+def test_bgp_addpath_best_selected():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r2 = tgen.gears["r2"]
+
+    def check_bgp_advertised_routes_to_r1():
+        output = json.loads(
+            r2.vtysh_cmd(
+                "show bgp ipv4 neighbors 192.168.1.1 advertised-routes detail json"
+            )
+        )
+        expected = {
+            "advertisedRoutes": {
+                "172.16.16.254/32": {
+                    "paths": [
+                        {
+                            "aspath": {
+                                "string": "65005",
+                            }
+                        },
+                        {
+                            "aspath": {
+                                "string": "65006",
+                            }
+                        },
+                    ]
+                }
+            },
+            "totalPrefixCounter": 2,
+        }
+
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(check_bgp_advertised_routes_to_r1)
+    success, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert (
+        result is None
+    ), "Received more/less Add-Path best paths, but should be only 1+1 (real best path)"
+
+    def check_bgp_advertised_routes_to_r7():
+        output = json.loads(
+            r2.vtysh_cmd(
+                "show bgp ipv4 neighbors 192.168.7.7 advertised-routes detail json"
+            )
+        )
+        expected = {
+            "advertisedRoutes": {
+                "172.16.16.254/32": {
+                    "paths": [
+                        {
+                            "aspath": {
+                                "string": "65004",
+                            }
+                        },
+                        {
+                            "aspath": {
+                                "string": "65005",
+                            }
+                        },
+                        {
+                            "aspath": {
+                                "string": "65006",
+                            }
+                        },
+                    ]
+                }
+            },
+            "totalPrefixCounter": 3,
+        }
+
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(check_bgp_advertised_routes_to_r7)
+    success, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert (
+        result is None
+    ), "Received more/less Add-Path best paths, but should be only 2+1 (real best path)"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))