bgpd: Add an option to limit outgoing prefixes

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

bgpd/bgp_updgrp.c

@@ -143,6 +143,7 @@ static void conf_copy(struct peer *dst, struct peer *src, afi_t afi,
 	dst->v_routeadv = src->v_routeadv;
 	dst->flags = src->flags;
 	dst->af_flags[afi][safi] = src->af_flags[afi][safi];
+	dst->pmax_out[afi][safi] = src->pmax_out[afi][safi];
 	XFREE(MTYPE_BGP_PEER_HOST, dst->host);
 
 	dst->host = XSTRDUP(MTYPE_BGP_PEER_HOST, src->host);

bgpd/bgp_updgrp.h

@@ -208,7 +208,7 @@ struct update_subgroup {
 	struct bgp_synchronize *sync;
 
 	/* send prefix count */
-	unsigned long scount;
+	uint32_t scount;
 
 	/* announcement attribute hash */
 	struct hash *hash;

bgpd/bgp_updgrp_packet.c

@@ -744,6 +744,22 @@ struct bpacket *subgroup_update_packet(struct update_subgroup *subgrp)
 		addpath_tx_id = adj->addpath_tx_id;
 		path = adv->pathi;
 
+		/* Check if we need to add a prefix to the packet if
+		 * maximum-prefix-out is set for the peer.
+		 */
+		if (CHECK_FLAG(peer->af_flags[afi][safi],
+			       PEER_FLAG_MAX_PREFIX_OUT)
+		    && subgrp->scount >= peer->pmax_out[afi][safi]) {
+			if (BGP_DEBUG(update, UPDATE_OUT)
+			    || BGP_DEBUG(update, UPDATE_PREFIX)) {
+				zlog_debug(
+					"%s reached maximum prefix to be send (%" PRIu32
+					")",
+					peer->host, peer->pmax_out[afi][safi]);
+			}
+			goto next;
+		}
+
 		space_remaining = STREAM_CONCAT_REMAIN(s, snlri, STREAM_SIZE(s))
 				  - BGP_MAX_PACKET_SIZE_OVERFLOW;
 		space_needed =
@@ -894,7 +910,7 @@ struct bpacket *subgroup_update_packet(struct update_subgroup *subgrp)
 			subgrp->scount++;
 
 		adj->attr = bgp_attr_intern(adv->baa->attr);
-
+next:
 		adv = bgp_advertise_clean_subgroup(subgrp, adj);
 	}
 

bgpd/bgp_vty.c

@@ -6058,6 +6058,56 @@ static int peer_maximum_prefix_unset_vty(struct vty *vty, const char *ip_str,
 	return bgp_vty_return(vty, ret);
 }
 
+/* Maximum number of prefix to be sent to the neighbor. */
+DEFUN(neighbor_maximum_prefix_out,
+      neighbor_maximum_prefix_out_cmd,
+      "neighbor <A.B.C.D|X:X::X:X|WORD> maximum-prefix-out (1-4294967295)",
+      NEIGHBOR_STR
+      NEIGHBOR_ADDR_STR2
+      "Maximum number of prefixes to be sent to this peer\n"
+      "Maximum no. of prefix limit\n")
+{
+	int idx_peer = 1;
+	int idx_number = 3;
+	struct peer *peer;
+	uint32_t max;
+	afi_t afi = bgp_node_afi(vty);
+	safi_t safi = bgp_node_safi(vty);
+
+	peer = peer_and_group_lookup_vty(vty, argv[idx_peer]->arg);
+	if (!peer)
+		return CMD_WARNING_CONFIG_FAILED;
+
+	max = strtoul(argv[idx_number]->arg, NULL, 10);
+
+	SET_FLAG(peer->af_flags[afi][safi], PEER_FLAG_MAX_PREFIX_OUT);
+	peer->pmax_out[afi][safi] = max;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(no_neighbor_maximum_prefix_out,
+      no_neighbor_maximum_prefix_out_cmd,
+      "no neighbor <A.B.C.D|X:X::X:X|WORD> maximum-prefix-out",
+      NO_STR
+      NEIGHBOR_STR
+      NEIGHBOR_ADDR_STR2
+      "Maximum number of prefixes to be sent to this peer\n")
+{
+	int idx_peer = 2;
+	struct peer *peer;
+	afi_t afi = bgp_node_afi(vty);
+	safi_t safi = bgp_node_safi(vty);
+
+	peer = peer_and_group_lookup_vty(vty, argv[idx_peer]->arg);
+	if (!peer)
+		return CMD_WARNING_CONFIG_FAILED;
+
+	peer->pmax_out[afi][safi] = 0;
+
+	return CMD_SUCCESS;
+}
+
 /* Maximum number of prefix configuration.  prefix count is different
    for each peer configuration.  So this configuration can be set for
    each peer configuration. */
@@ -9190,6 +9240,11 @@ static void bgp_show_peer_afi(struct vty *vty, struct peer *p, afi_t afi,
 			json_object_int_add(json_addr, "sentPrefixCounter",
 						(PAF_SUBGRP(paf))->scount);
 
+		/* Maximum prefix */
+		if (CHECK_FLAG(p->af_flags[afi][safi], PEER_FLAG_MAX_PREFIX_OUT))
+			json_object_int_add(json_addr, "prefixOutAllowedMax",
+					    p->pmax_out[afi][safi]);
+
 		/* Maximum prefix */
 		if (CHECK_FLAG(p->af_flags[afi][safi], PEER_FLAG_MAX_PREFIX)) {
 			json_object_int_add(json_addr, "prefixAllowedMax",
@@ -9476,6 +9531,13 @@ static void bgp_show_peer_afi(struct vty *vty, struct peer *p, afi_t afi,
 		vty_out(vty, "  %" PRIu32 " accepted prefixes\n",
 			p->pcount[afi][safi]);
 
+		/* maximum-prefix-out */
+		if (CHECK_FLAG(p->af_flags[afi][safi],
+			       PEER_FLAG_MAX_PREFIX_OUT))
+			vty_out(vty,
+				"  Maximum allowed prefixes sent %" PRIu32 "\n",
+				p->pmax_out[afi][safi]);
+
 		/* Maximum prefix */
 		if (CHECK_FLAG(p->af_flags[afi][safi], PEER_FLAG_MAX_PREFIX)) {
 			vty_out(vty,
@@ -13579,6 +13641,11 @@ static void bgp_config_write_peer_af(struct vty *vty, struct bgp *bgp,
 		vty_out(vty, "\n");
 	}
 
+	/* maximum-prefix-out */
+	if (peergroup_af_flag_check(peer, afi, safi, PEER_FLAG_MAX_PREFIX_OUT))
+		vty_out(vty, "  neighbor %s maximum-prefix-out %" PRIu32 "\n",
+			addr, peer->pmax_out[afi][safi]);
+
 	/* Route server client. */
 	if (peergroup_af_flag_check(peer, afi, safi,
 				    PEER_FLAG_RSERVER_CLIENT)) {
@@ -15115,6 +15182,26 @@ void bgp_vty_init(void)
 	install_element(BGP_VPNV6_NODE, &neighbor_unsuppress_map_cmd);
 	install_element(BGP_VPNV6_NODE, &no_neighbor_unsuppress_map_cmd);
 
+	/* neighbor maximum-prefix-out commands. */
+	install_element(BGP_NODE, &neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_NODE, &no_neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV4_NODE, &neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV4_NODE, &no_neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV4M_NODE, &neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV4M_NODE, &no_neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV4L_NODE, &neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV4L_NODE, &no_neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV6_NODE, &neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV6_NODE, &no_neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV6M_NODE, &neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV6M_NODE, &no_neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV6L_NODE, &neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_IPV6L_NODE, &no_neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_VPNV4_NODE, &neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_VPNV4_NODE, &no_neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_VPNV6_NODE, &neighbor_maximum_prefix_out_cmd);
+	install_element(BGP_VPNV6_NODE, &no_neighbor_maximum_prefix_out_cmd);
+
 	/* "neighbor maximum-prefix" commands. */
 	install_element(BGP_NODE, &neighbor_maximum_prefix_hidden_cmd);
 	install_element(BGP_NODE,

bgpd/bgpd.h

@@ -988,6 +988,7 @@ struct peer {
 #define PEER_FLAG_WEIGHT                    (1 << 24) /* weight */
 #define PEER_FLAG_ALLOWAS_IN_ORIGIN         (1 << 25) /* allowas-in origin */
 #define PEER_FLAG_SEND_LARGE_COMMUNITY      (1 << 26) /* Send large Communities */
+#define PEER_FLAG_MAX_PREFIX_OUT            (1 << 27) /* outgoing maximum prefix */
 
 	enum bgp_addpath_strat addpath_type[AFI_MAX][SAFI_MAX];
 
@@ -1120,9 +1121,6 @@ struct peer {
 	/* timestamp when the last msg was written */
 	_Atomic time_t last_update;
 
-	/* Send prefix count. */
-	unsigned long scount[AFI_MAX][SAFI_MAX];
-
 	/* Notify data. */
 	struct bgp_notify notify;
 
@@ -1173,6 +1171,9 @@ struct peer {
 	uint16_t pmax_restart[AFI_MAX][SAFI_MAX];
 #define MAXIMUM_PREFIX_THRESHOLD_DEFAULT 75
 
+	/* Send prefix count. */
+	uint32_t pmax_out[AFI_MAX][SAFI_MAX];
+
 	/* allowas-in. */
 	char allowas_in[AFI_MAX][SAFI_MAX];