bgpd: Activate ipv6-unicast for peer automatically if globally defined

When you use a single BGP session for both IPv4 and IPv6 it's a bit
annoying going into ipv6 address-family and explicitly activating it.

Let's get this automatically if enabled with `bgp default ipv6-unicast`.

Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>

6 files changed, 111 insertions, 60 deletions

diff --git a/bgpd/bgp_nb_config.c b/bgpd/bgp_nb_config.c
index 721ce5b5c6..d75a6a65e1 100644
--- a/bgpd/bgp_nb_config.c
+++ b/bgpd/bgp_nb_config.c
@@ -3146,8 +3146,7 @@ int bgp_neighbors_neighbor_neighbor_remote_as_remote_as_type_modify(
 			return NB_OK;
 
 		str2sockunion(peer_str, &su);
-		ret = peer_remote_as(bgp, &su, NULL, &as, as_type, AFI_IP,
-				     SAFI_UNICAST);
+		ret = peer_remote_as(bgp, &su, NULL, &as, as_type);
 		if (bgp_nb_errmsg_return(args->errmsg, args->errmsg_len, ret)
 		    < 0)
 			return NB_ERR_INCONSISTENCY;
@@ -3202,8 +3201,7 @@ int bgp_neighbors_neighbor_neighbor_remote_as_remote_as_modify(
 		as = yang_dnode_get_uint32(args->dnode, NULL);
 
 		str2sockunion(peer_str, &su);
-		ret = peer_remote_as(bgp, &su, NULL, &as, as_type, AFI_IP,
-				     SAFI_UNICAST);
+		ret = peer_remote_as(bgp, &su, NULL, &as, as_type);
 		if (bgp_nb_errmsg_return(args->errmsg, args->errmsg_len, ret)
 		    < 0)
 			return NB_ERR_INCONSISTENCY;
@@ -4370,8 +4368,7 @@ int bgp_neighbors_unnumbered_neighbor_create(struct nb_cb_create_args *args)
 					"./neighbor-remote-as/remote-as");
 		}
 
-		if (peer_conf_interface_create(bgp, peer_str, AFI_IP,
-					       SAFI_UNICAST, v6_only,
+		if (peer_conf_interface_create(bgp, peer_str, v6_only,
 					       peer_grp_str, as_type, as,
 					       args->errmsg, args->errmsg_len))
 			return NB_ERR_INCONSISTENCY;
@@ -4440,9 +4437,9 @@ int bgp_neighbors_unnumbered_neighbor_v6only_modify(
 
 		v6_only = yang_dnode_get_bool(args->dnode, NULL);
 
-		if (peer_conf_interface_create(
-			    bgp, peer_str, AFI_IP, SAFI_UNICAST, v6_only, NULL,
-			    AS_UNSPECIFIED, 0, args->errmsg, args->errmsg_len))
+		if (peer_conf_interface_create(bgp, peer_str, v6_only, NULL,
+					       AS_UNSPECIFIED, 0, args->errmsg,
+					       args->errmsg_len))
 			return NB_ERR_INCONSISTENCY;
 
 		break;
@@ -5174,8 +5171,6 @@ void bgp_neighbors_unnumbered_neighbor_neighbor_remote_as_apply_finish(
 	int ret;
 	as_t as = 0;
 	struct peer *peer = NULL;
-	afi_t afi = AFI_IP;
-	safi_t safi = SAFI_UNICAST;
 
 	bgp = nb_running_get_entry(args->dnode, NULL, true);
 	peer_str = yang_dnode_get_string(args->dnode, "../interface");
@@ -5185,7 +5180,7 @@ void bgp_neighbors_unnumbered_neighbor_neighbor_remote_as_apply_finish(
 
 	peer = peer_lookup_by_conf_if(bgp, peer_str);
 
-	ret = peer_remote_as(bgp, NULL, peer_str, &as, as_type, afi, safi);
+	ret = peer_remote_as(bgp, NULL, peer_str, &as, as_type);
 
 	if (ret < 0 && !peer) {
 		snprintf(args->errmsg, args->errmsg_len,
diff --git a/bgpd/bgp_network.c b/bgpd/bgp_network.c
index be2c474493..be3a8f3c1f 100644
--- a/bgpd/bgp_network.c
+++ b/bgpd/bgp_network.c
@@ -554,7 +554,7 @@ static int bgp_accept(struct thread *thread)
 				peer1->host);
 
 	peer = peer_create(&su, peer1->conf_if, peer1->bgp, peer1->local_as,
-			   peer1->as, peer1->as_type, 0, 0, NULL);
+			   peer1->as, peer1->as_type, NULL);
 	hash_release(peer->bgp->peerhash, peer);
 	hash_get(peer->bgp->peerhash, peer, hash_alloc_intern);
 
diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index 9e8065691e..0654adb646 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -3726,6 +3726,29 @@ DEFPY (no_bgp_bestpath_bw,
 	return CMD_SUCCESS;
 }
 
+/* "no bgp default ipv6-unicast". */
+DEFUN(no_bgp_default_ipv6_unicast, no_bgp_default_ipv6_unicast_cmd,
+      "no bgp default ipv6-unicast", NO_STR
+      "BGP specific commands\n"
+      "Configure BGP defaults\n"
+      "Activate ipv6-unicast for a peer by default\n")
+{
+	VTY_DECLVAR_CONTEXT(bgp, bgp);
+	UNSET_FLAG(bgp->flags, BGP_FLAG_DEFAULT_IPV6);
+	return CMD_SUCCESS;
+}
+
+DEFUN(bgp_default_ipv6_unicast, bgp_default_ipv6_unicast_cmd,
+      "bgp default ipv6-unicast",
+      "BGP specific commands\n"
+      "Configure BGP defaults\n"
+      "Activate ipv6-unicast for a peer by default\n")
+{
+	VTY_DECLVAR_CONTEXT(bgp, bgp);
+	SET_FLAG(bgp->flags, BGP_FLAG_DEFAULT_IPV6);
+	return CMD_SUCCESS;
+}
+
 /* "no bgp default ipv4-unicast". */
 DEFUN (no_bgp_default_ipv4_unicast,
        no_bgp_default_ipv4_unicast_cmd,
@@ -4367,10 +4390,10 @@ DEFUN_YANG(neighbor_remote_as,
 	return nb_cli_apply_changes(vty, base_xpath);
 }
 
-int peer_conf_interface_create(struct bgp *bgp, const char *conf_if, afi_t afi,
-			       safi_t safi, bool v6only,
-			       const char *peer_group_name, int as_type,
-			       as_t as, char *errmsg, size_t errmsg_len)
+int peer_conf_interface_create(struct bgp *bgp, const char *conf_if,
+			       bool v6only, const char *peer_group_name,
+			       int as_type, as_t as, char *errmsg,
+			       size_t errmsg_len)
 {
 	struct peer *peer;
 	struct peer_group *group;
@@ -4387,16 +4410,10 @@ int peer_conf_interface_create(struct bgp *bgp, const char *conf_if, afi_t afi,
 	peer = peer_lookup_by_conf_if(bgp, conf_if);
 	if (peer) {
 		if (as_type != AS_UNSPECIFIED)
-			ret = peer_remote_as(bgp, NULL, conf_if, &as, as_type,
-					     afi, safi);
+			ret = peer_remote_as(bgp, NULL, conf_if, &as, as_type);
 	} else {
-		if (CHECK_FLAG(bgp->flags, BGP_FLAG_NO_DEFAULT_IPV4)
-		    && afi == AFI_IP && safi == SAFI_UNICAST)
-			peer = peer_create(NULL, conf_if, bgp, bgp->as, as,
-					   as_type, 0, 0, NULL);
-		else
-			peer = peer_create(NULL, conf_if, bgp, bgp->as, as,
-					   as_type, afi, safi, NULL);
+		peer = peer_create(NULL, conf_if, bgp, bgp->as, as, as_type,
+				   NULL);
 
 		if (!peer) {
 			snprintf(errmsg, errmsg_len,
@@ -16799,18 +16816,36 @@ static void bgp_config_write_peer_af(struct vty *vty, struct bgp *bgp,
 		}
 	} else {
 		if (peer->afc[afi][safi]) {
-			if ((afi == AFI_IP) && (safi == SAFI_UNICAST)) {
-				if (CHECK_FLAG(bgp->flags,
-					       BGP_FLAG_NO_DEFAULT_IPV4)) {
+			if ((afi == AFI_IP || afi == AFI_IP6)
+			    && safi == SAFI_UNICAST) {
+				if (afi == AFI_IP
+				    && CHECK_FLAG(bgp->flags,
+						  BGP_FLAG_NO_DEFAULT_IPV4)) {
+					vty_out(vty, "  neighbor %s activate\n",
+						addr);
+				} else if (afi == AFI_IP6
+					   && !CHECK_FLAG(
+						      bgp->flags,
+						      BGP_FLAG_DEFAULT_IPV6)) {
 					vty_out(vty, "  neighbor %s activate\n",
 						addr);
 				}
-			} else
+			} else {
 				vty_out(vty, "  neighbor %s activate\n", addr);
+			}
 		} else {
-			if ((afi == AFI_IP) && (safi == SAFI_UNICAST)) {
-				if (!CHECK_FLAG(bgp->flags,
-						BGP_FLAG_NO_DEFAULT_IPV4)) {
+			if ((afi == AFI_IP || afi == AFI_IP6)
+			    && safi == SAFI_UNICAST) {
+				if (afi == AFI_IP
+				    && !CHECK_FLAG(bgp->flags,
+						  BGP_FLAG_NO_DEFAULT_IPV4)) {
+					vty_out(vty,
+						"  no neighbor %s activate\n",
+						addr);
+				} else if (afi == AFI_IP6
+					   && CHECK_FLAG(
+						      bgp->flags,
+						      BGP_FLAG_DEFAULT_IPV6)) {
 					vty_out(vty,
 						"  no neighbor %s activate\n",
 						addr);
@@ -17244,6 +17279,10 @@ int bgp_config_write(struct vty *vty)
 		if (CHECK_FLAG(bgp->flags, BGP_FLAG_NO_DEFAULT_IPV4))
 			vty_out(vty, " no bgp default ipv4-unicast\n");
 
+		/* BGP default ipv6-unicast. */
+		if (CHECK_FLAG(bgp->flags, BGP_FLAG_DEFAULT_IPV6))
+			vty_out(vty, " bgp default ipv6-unicast\n");
+
 		/* BGP default local-preference. */
 		if (bgp->default_local_pref != BGP_DEFAULT_LOCAL_PREF)
 			vty_out(vty, " bgp default local-preference %u\n",
@@ -17914,6 +17953,10 @@ void bgp_vty_init(void)
 	install_element(BGP_NODE, &no_bgp_default_ipv4_unicast_cmd);
 	install_element(BGP_NODE, &bgp_default_ipv4_unicast_cmd);
 
+	/* "no bgp default ipv6-unicast" commands. */
+	install_element(BGP_NODE, &no_bgp_default_ipv6_unicast_cmd);
+	install_element(BGP_NODE, &bgp_default_ipv6_unicast_cmd);
+
 	/* "bgp network import-check" commands. */
 	install_element(BGP_NODE, &bgp_network_import_check_cmd);
 	install_element(BGP_NODE, &bgp_network_import_check_exact_cmd);
diff --git a/bgpd/bgp_vty.h b/bgpd/bgp_vty.h
index 85619dd074..251bdc3fe3 100644
--- a/bgpd/bgp_vty.h
+++ b/bgpd/bgp_vty.h
@@ -205,9 +205,9 @@ extern int peer_local_interface_cfg(struct bgp *bgp, const char *ip_str,
 				    const char *str, char *errmsg,
 				    size_t errmsg_len);
 extern int peer_conf_interface_create(struct bgp *bgp, const char *conf_if,
-				      afi_t afi, safi_t safi, bool v6only,
-				      const char *peer_group_name, int as_type,
-				      as_t as, char *errmsg, size_t errmsg_len);
+				      bool v6only, const char *peer_group_name,
+				      int as_type, as_t as, char *errmsg,
+				      size_t errmsg_len);
 extern int peer_flag_modify_nb(struct bgp *bgp, const char *ip_str,
 			       struct peer *peer, uint32_t flag, bool set,
 			       char *errmsg, size_t errmsg_len);
diff --git a/bgpd/bgpd.c b/bgpd/bgpd.c
index 07ca247ee6..c259fcdc7b 100644
--- a/bgpd/bgpd.c
+++ b/bgpd/bgpd.c
@@ -1467,8 +1467,10 @@ void peer_xfer_config(struct peer *peer_dst, struct peer *peer_src)
 
 	for (afidx = BGP_AF_START; afidx < BGP_AF_MAX; afidx++) {
 		paf = peer_src->peer_af_array[afidx];
-		if (paf != NULL)
-			peer_af_create(peer_dst, paf->afi, paf->safi);
+		if (paf != NULL) {
+			if (!peer_af_find(peer_dst, paf->afi, paf->safi))
+				peer_af_create(peer_dst, paf->afi, paf->safi);
+		}
 	}
 
 	/* update-source apply */
@@ -1682,12 +1684,13 @@ void bgp_recalculate_all_bestpaths(struct bgp *bgp)
  */
 struct peer *peer_create(union sockunion *su, const char *conf_if,
 			 struct bgp *bgp, as_t local_as, as_t remote_as,
-			 int as_type, afi_t afi, safi_t safi,
-			 struct peer_group *group)
+			 int as_type, struct peer_group *group)
 {
 	int active;
 	struct peer *peer;
 	char buf[SU_ADDRSTRLEN];
+	afi_t afi;
+	safi_t safi;
 
 	peer = peer_new(bgp);
 	if (conf_if) {
@@ -1746,9 +1749,23 @@ struct peer *peer_create(union sockunion *su, const char *conf_if,
 
 	SET_FLAG(peer->flags, PEER_FLAG_CONFIG_NODE);
 
-	if (afi && safi) {
-		peer->afc[afi][safi] = 1;
-		peer_af_create(peer, afi, safi);
+	/* If address family is IPv4 and `bgp default ipv4-unicast` (default),
+	 * then activate the neighbor for this AF.
+	 * If address family is IPv6 and `bgp default ipv6-unicast`
+	 * (non-default), then activate the neighbor for this AF.
+	 */
+	FOREACH_AFI_SAFI (afi, safi) {
+		if ((afi == AFI_IP || afi == AFI_IP6) && safi == SAFI_UNICAST) {
+			if ((afi == AFI_IP
+			     && !CHECK_FLAG(bgp->flags,
+					    BGP_FLAG_NO_DEFAULT_IPV4))
+			    || (afi == AFI_IP6
+				&& CHECK_FLAG(bgp->flags,
+					      BGP_FLAG_DEFAULT_IPV6))) {
+				peer->afc[afi][safi] = 1;
+				peer_af_create(peer, afi, safi);
+			}
+		}
 	}
 
 	/* auto shutdown if configured */
@@ -1877,7 +1894,7 @@ void peer_as_change(struct peer *peer, as_t as, int as_specified)
 /* If peer does not exist, create new one.  If peer already exists,
    set AS number to the peer.  */
 int peer_remote_as(struct bgp *bgp, union sockunion *su, const char *conf_if,
-		   as_t *as, int as_type, afi_t afi, safi_t safi)
+		   as_t *as, int as_type)
 {
 	struct peer *peer;
 	as_t local_as;
@@ -1945,16 +1962,7 @@ int peer_remote_as(struct bgp *bgp, union sockunion *su, const char *conf_if,
 		else
 			local_as = bgp->as;
 
-		/* If this is IPv4 unicast configuration and "no bgp default
-		   ipv4-unicast" is specified. */
-
-		if (CHECK_FLAG(bgp->flags, BGP_FLAG_NO_DEFAULT_IPV4)
-		    && afi == AFI_IP && safi == SAFI_UNICAST)
-			peer_create(su, conf_if, bgp, local_as, *as, as_type, 0,
-				    0, NULL);
-		else
-			peer_create(su, conf_if, bgp, local_as, *as, as_type,
-				    afi, safi, NULL);
+		peer_create(su, conf_if, bgp, local_as, *as, as_type, NULL);
 	}
 
 	return 0;
@@ -2561,6 +2569,8 @@ struct peer_group *peer_group_get(struct bgp *bgp, const char *name)
 	group->conf = peer_new(bgp);
 	if (!CHECK_FLAG(bgp->flags, BGP_FLAG_NO_DEFAULT_IPV4))
 		group->conf->afc[AFI_IP][SAFI_UNICAST] = 1;
+	if (CHECK_FLAG(bgp->flags, BGP_FLAG_DEFAULT_IPV6))
+		group->conf->afc[AFI_IP6][SAFI_UNICAST] = 1;
 	XFREE(MTYPE_BGP_PEER_HOST, group->conf->host);
 	group->conf->host = XSTRDUP(MTYPE_BGP_PEER_HOST, name);
 	group->conf->group = group;
@@ -2995,7 +3005,7 @@ int peer_group_bind(struct bgp *bgp, union sockunion *su, struct peer *peer,
 		}
 
 		peer = peer_create(su, NULL, bgp, bgp->as, group->conf->as,
-				   group->conf->as_type, 0, 0, group);
+				   group->conf->as_type, group);
 
 		peer = peer_lock(peer); /* group->peer list reference */
 		listnode_add(group->peer, peer);
@@ -3007,7 +3017,10 @@ int peer_group_bind(struct bgp *bgp, union sockunion *su, struct peer *peer,
 		FOREACH_AFI_SAFI (afi, safi) {
 			if (group->conf->afc[afi][safi]) {
 				peer->afc[afi][safi] = 1;
-				peer_af_create(peer, afi, safi);
+
+				if (!peer_af_find(peer, afi, safi))
+					peer_af_create(peer, afi, safi);
+
 				peer_group2peer_config_copy_af(group, peer, afi,
 							       safi);
 			} else if (peer->afc[afi][safi])
@@ -3806,7 +3819,7 @@ struct peer *peer_create_bind_dynamic_neighbor(struct bgp *bgp,
 
 	/* Create peer first; we've already checked group config is valid. */
 	peer = peer_create(su, NULL, bgp, bgp->as, group->conf->as,
-			   group->conf->as_type, 0, 0, group);
+			   group->conf->as_type, group);
 	if (!peer)
 		return NULL;
 
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index e79dccdab8..c0bb8cc634 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -477,6 +477,7 @@ struct bgp {
 #define BGP_FLAG_SHUTDOWN                 (1 << 27)
 #define BGP_FLAG_SUPPRESS_FIB_PENDING     (1 << 28)
 #define BGP_FLAG_SUPPRESS_DUPLICATES      (1 << 29)
+#define BGP_FLAG_DEFAULT_IPV6             (1 << 30)
 
 	enum global_mode GLOBAL_GR_FSM[BGP_GLOBAL_GR_MODE]
 				      [BGP_GLOBAL_GR_EVENT_CMD];
@@ -1916,8 +1917,7 @@ extern bool peer_active(struct peer *);
 extern bool peer_active_nego(struct peer *);
 extern void bgp_recalculate_all_bestpaths(struct bgp *bgp);
 extern struct peer *peer_create(union sockunion *, const char *, struct bgp *,
-				as_t, as_t, int, afi_t, safi_t,
-				struct peer_group *);
+				as_t, as_t, int, struct peer_group *);
 extern struct peer *peer_create_accept(struct bgp *);
 extern void peer_xfer_config(struct peer *dst, struct peer *src);
 extern char *peer_uptime(time_t uptime2, char *buf, size_t len, bool use_json,
@@ -1985,7 +1985,7 @@ extern bool bgp_update_delay_configured(struct bgp *);
 extern int bgp_afi_safi_peer_exists(struct bgp *bgp, afi_t afi, safi_t safi);
 extern void peer_as_change(struct peer *, as_t, int);
 extern int peer_remote_as(struct bgp *, union sockunion *, const char *, as_t *,
-			  int, afi_t, safi_t);
+			  int);
 extern int peer_group_remote_as(struct bgp *, const char *, as_t *, int);
 extern int peer_delete(struct peer *peer);
 extern void peer_notify_unconfig(struct peer *peer);