Merge pull request #4144 from pguibert6WIND/bfd_cbit

BFD CBIT

31 files changed, 964 insertions, 27 deletions

diff --git a/bfdd/bfd.c b/bfdd/bfd.c
index 57d8ffa6d..435443182 100644
--- a/bfdd/bfd.c
+++ b/bfdd/bfd.c
@@ -600,6 +600,17 @@ skip_echo:
 		bfd_recvtimer_update(bs);
 		bfd_xmttimer_update(bs, bs->xmt_TO);
 	}
+	if (bpc->bpc_cbit) {
+		if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_CBIT))
+			return;
+
+		BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_CBIT);
+	} else {
+		if (!BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_CBIT))
+			return;
+
+		BFD_UNSET_FLAG(bs->flags, BFD_SESS_FLAG_CBIT);
+	}
 }
 
 static int bfd_session_update(struct bfd_session *bs, struct bfd_peer_cfg *bpc)
diff --git a/bfdd/bfd.h b/bfdd/bfd.h
index 3f3d60383..213e905bf 100644
--- a/bfdd/bfd.h
+++ b/bfdd/bfd.h
@@ -129,6 +129,12 @@ struct bfd_echo_pkt {
 			flags |= (val & 0x3) << 6;                             \
 	}
 #define BFD_GETSTATE(flags) ((flags >> 6) & 0x3)
+#define BFD_SETCBIT(flags, val)                                                \
+	{                                                                      \
+		if ((val))                                                     \
+			flags |= val;                                          \
+	}
+#define BFD_GETCBIT(flags) (flags & BFD_FBIT)
 #define BFD_ECHO_VERSION 1
 #define BFD_ECHO_PKT_LEN sizeof(struct bfd_echo_pkt)
 
@@ -168,6 +174,7 @@ enum bfd_session_flags {
 						 */
 	BFD_SESS_FLAG_SHUTDOWN = 1 << 7,	/* disable BGP peer function */
 	BFD_SESS_FLAG_CONFIG = 1 << 8,	/* Session configured with bfd NB API */
+	BFD_SESS_FLAG_CBIT = 1 << 9,	/* CBIT is set */
 };
 
 #define BFD_SET_FLAG(field, flag) (field |= flag)
@@ -210,6 +217,7 @@ struct bfd_session {
 	uint8_t detect_mult;
 	uint8_t remote_detect_mult;
 	uint8_t mh_ttl;
+	uint8_t remote_cbit;
 
 	/* Timers */
 	struct bfd_timers timers;
diff --git a/bfdd/bfd_packet.c b/bfdd/bfd_packet.c
index 8edba05d1..f3acfa416 100644
--- a/bfdd/bfd_packet.c
+++ b/bfdd/bfd_packet.c
@@ -221,6 +221,10 @@ void ptm_bfd_snd(struct bfd_session *bfd, int fbit)
 	BFD_SETVER(cp.diag, BFD_VERSION);
 	cp.flags = 0;
 	BFD_SETSTATE(cp.flags, bfd->ses_state);
+
+	if (BFD_CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_CBIT))
+		BFD_SETCBIT(cp.flags, BFD_CBIT);
+
 	BFD_SETDEMANDBIT(cp.flags, BFD_DEF_DEMAND);
 
 	/*
@@ -646,6 +650,11 @@ int bfd_recv_cb(struct thread *t)
 		ntohl(cp->timers.required_min_echo);
 	bfd->remote_detect_mult = cp->detect_mult;
 
+	if (BFD_GETCBIT(cp->flags))
+		bfd->remote_cbit = 1;
+	else
+		bfd->remote_cbit = 0;
+
 	/* State switch from section 6.2. */
 	bs_state_handler(bfd, BFD_GETSTATE(cp->flags));
 
diff --git a/bfdd/bfdctl.h b/bfdd/bfdctl.h
index 0da1ca8df..4ce23a8f2 100644
--- a/bfdd/bfdctl.h
+++ b/bfdd/bfdctl.h
@@ -88,6 +88,8 @@ struct bfd_peer_cfg {
 	bool bpc_createonly;
 	bool bpc_shutdown;
 
+	bool bpc_cbit;
+
 	/* Status information */
 	enum bfd_peer_status bpc_bps;
 	uint32_t bpc_id;
diff --git a/bfdd/ptm_adapter.c b/bfdd/ptm_adapter.c
index a12a3c196..3e2ace6ea 100644
--- a/bfdd/ptm_adapter.c
+++ b/bfdd/ptm_adapter.c
@@ -89,6 +89,7 @@ static void debug_printbpc(const char *func, unsigned int line,
 {
 	char addr[3][128];
 	char timers[3][128];
+	char cbit_str[10];
 
 	addr[0][0] = addr[1][0] = addr[2][0] = timers[0][0] = timers[1][0] =
 		timers[2][0] = 0;
@@ -117,9 +118,11 @@ static void debug_printbpc(const char *func, unsigned int line,
 		snprintf(timers[2], sizeof(timers[2]), " detect-multiplier:%d",
 			 bpc->bpc_detectmultiplier);
 
-	log_debug("%s:%d: %s %s%s%s%s%s%s", func, line,
+	sprintf(cbit_str, "CB %x", bpc->bpc_cbit);
+
+	log_debug("%s:%d: %s %s%s%s%s%s%s %s", func, line,
 		  bpc->bpc_mhop ? "multi-hop" : "single-hop", addr[0], addr[1],
-		  addr[2], timers[0], timers[1], timers[2]);
+		  addr[2], timers[0], timers[1], timers[2], cbit_str);
 }
 
 #define DEBUG_PRINTBPC(bpc) debug_printbpc(__FILE__, __LINE__, (bpc))
@@ -173,6 +176,7 @@ int ptm_bfd_notify(struct bfd_session *bs)
 	 *   - AF_INET6:
 	 *     - 16 bytes: ipv6
 	 *   - c: prefix length
+	 * - c: cbit
 	 *
 	 * Commands: ZEBRA_BFD_DEST_REPLAY
 	 *
@@ -219,6 +223,8 @@ int ptm_bfd_notify(struct bfd_session *bs)
 	/* BFD source prefix information. */
 	_ptm_msg_address(msg, bs->key.family, &bs->key.local);
 
+	stream_putc(msg, bs->remote_cbit);
+
 	/* Write packet size. */
 	stream_putw_at(msg, 0, stream_get_endp(msg));
 
@@ -293,6 +299,7 @@ static int _ptm_msg_read(struct stream *msg, int command, vrf_id_t vrf_id,
 	 *       - 16 bytes: ipv6 address
 	 *     - c: ifname length
 	 *     - X bytes: interface name
+	 * - c: bfd_cbit
 	 *
 	 * q(64), l(32), w(16), c(8)
 	 */
@@ -371,6 +378,8 @@ static int _ptm_msg_read(struct stream *msg, int command, vrf_id_t vrf_id,
 		}
 	}
 
+	STREAM_GETC(msg, bpc->bpc_cbit);
+
 	/* Sanity check: peer and local address must match IP types. */
 	if (bpc->bpc_local.sa_sin.sin_family != 0
 	    && (bpc->bpc_local.sa_sin.sin_family
diff --git a/bgpd/bgp_bfd.c b/bgpd/bgp_bfd.c
index a9c30acaf..57fef8e91 100644
--- a/bgpd/bgp_bfd.c
+++ b/bgpd/bgp_bfd.c
@@ -96,7 +96,7 @@ int bgp_bfd_is_peer_multihop(struct peer *peer)
 static void bgp_bfd_peer_sendmsg(struct peer *peer, int command)
 {
 	struct bfd_info *bfd_info;
-	int multihop;
+	int multihop, cbit = 0;
 	vrf_id_t vrf_id;
 
 	bfd_info = (struct bfd_info *)peer->bfd_info;
@@ -112,20 +112,30 @@ static void bgp_bfd_peer_sendmsg(struct peer *peer, int command)
 		if ((command == ZEBRA_BFD_DEST_REGISTER) && multihop)
 			SET_FLAG(bfd_info->flags, BFD_FLAG_BFD_TYPE_MULTIHOP);
 	}
+	/* while graceful restart with fwd path preserved
+	 * and bfd controlplane check not configured is not kept
+	 * keep bfd independent controlplane bit set to 1
+	 */
+	if (!bgp_flag_check(peer->bgp, BGP_FLAG_GRACEFUL_RESTART)
+	    && !bgp_flag_check(peer->bgp, BGP_FLAG_GR_PRESERVE_FWD)
+	    && !CHECK_FLAG(bfd_info->flags, BFD_FLAG_BFD_CHECK_CONTROLPLANE))
+		SET_FLAG(bfd_info->flags,  BFD_FLAG_BFD_CBIT_ON);
+
+	cbit = CHECK_FLAG(bfd_info->flags, BFD_FLAG_BFD_CBIT_ON);
 
 	if (peer->su.sa.sa_family == AF_INET)
 		bfd_peer_sendmsg(
 			zclient, bfd_info, AF_INET, &peer->su.sin.sin_addr,
 			(peer->su_local) ? &peer->su_local->sin.sin_addr : NULL,
 			(peer->nexthop.ifp) ? peer->nexthop.ifp->name : NULL,
-			peer->ttl, multihop, command, 1, vrf_id);
+			peer->ttl, multihop, cbit, command, 1, vrf_id);
 	else if (peer->su.sa.sa_family == AF_INET6)
 		bfd_peer_sendmsg(
 			zclient, bfd_info, AF_INET6, &peer->su.sin6.sin6_addr,
 			(peer->su_local) ? &peer->su_local->sin6.sin6_addr
 					 : NULL,
 			(peer->nexthop.ifp) ? peer->nexthop.ifp->name : NULL,
-			peer->ttl, multihop, command, 1, vrf_id);
+			peer->ttl, multihop, cbit, command, 1, vrf_id);
 }
 
 /*
@@ -260,7 +270,8 @@ static int bgp_bfd_dest_replay(ZAPI_CALLBACK_ARGS)
  *                              down the peer if the BFD session went down from
  * *                              up.
  */
-static void bgp_bfd_peer_status_update(struct peer *peer, int status)
+static void bgp_bfd_peer_status_update(struct peer *peer, int status,
+				       int remote_cbit)
 {
 	struct bfd_info *bfd_info;
 	int old_status;
@@ -280,6 +291,14 @@ static void bgp_bfd_peer_status_update(struct peer *peer, int status)
 				   bfd_get_status_str(status));
 	}
 	if ((status == BFD_STATUS_DOWN) && (old_status == BFD_STATUS_UP)) {
+		if (CHECK_FLAG(peer->sflags, PEER_STATUS_NSF_MODE) &&
+		    CHECK_FLAG(bfd_info->flags, BFD_FLAG_BFD_CHECK_CONTROLPLANE) &&
+		    !remote_cbit) {
+			zlog_info("%s BFD DOWN message ignored in the process"
+				  " of graceful restart when C bit is cleared",
+				  peer->host);
+			return;
+		}
 		peer->last_reset = PEER_DOWN_BFD_DOWN;
 		BGP_EVENT_ADD(peer, BGP_Stop);
 	}
@@ -303,23 +322,27 @@ static int bgp_bfd_dest_update(ZAPI_CALLBACK_ARGS)
 	struct prefix dp;
 	struct prefix sp;
 	int status;
+	int remote_cbit;
 
-	ifp = bfd_get_peer_info(zclient->ibuf, &dp, &sp, &status, vrf_id);
+	ifp = bfd_get_peer_info(zclient->ibuf, &dp, &sp, &status,
+				&remote_cbit, vrf_id);
 
 	if (BGP_DEBUG(zebra, ZEBRA)) {
 		char buf[2][PREFIX2STR_BUFFER];
 		prefix2str(&dp, buf[0], sizeof(buf[0]));
 		if (ifp) {
 			zlog_debug(
-				"Zebra: vrf %u interface %s bfd destination %s %s",
+				"Zebra: vrf %u interface %s bfd destination %s %s %s",
 				vrf_id, ifp->name, buf[0],
-				bfd_get_status_str(status));
+				bfd_get_status_str(status),
+				remote_cbit ? "(cbit on)" : "");
 		} else {
 			prefix2str(&sp, buf[1], sizeof(buf[1]));
 			zlog_debug(
-				"Zebra: vrf %u source %s bfd destination %s %s",
+				"Zebra: vrf %u source %s bfd destination %s %s %s",
 				vrf_id, buf[1], buf[0],
-				bfd_get_status_str(status));
+				bfd_get_status_str(status),
+				remote_cbit ? "(cbit on)" : "");
 		}
 	}
 
@@ -351,7 +374,8 @@ static int bgp_bfd_dest_update(ZAPI_CALLBACK_ARGS)
 
 				if (ifp && (ifp == peer->nexthop.ifp)) {
 					bgp_bfd_peer_status_update(peer,
-								   status);
+								   status,
+								   remote_cbit);
 				} else {
 					if (!peer->su_local)
 						continue;
@@ -381,7 +405,8 @@ static int bgp_bfd_dest_update(ZAPI_CALLBACK_ARGS)
 						continue;
 
 					bgp_bfd_peer_status_update(peer,
-								   status);
+								   status,
+								   remote_cbit);
 				}
 			}
 	}
@@ -534,6 +559,9 @@ void bgp_bfd_peer_config_write(struct vty *vty, struct peer *peer, char *addr)
 	if (!CHECK_FLAG(bfd_info->flags, BFD_FLAG_PARAM_CFG)
 	    && (bfd_info->type == BFD_TYPE_NOT_CONFIGURED))
 		vty_out(vty, " neighbor %s bfd\n", addr);
+
+	if (CHECK_FLAG(bfd_info->flags, BFD_FLAG_BFD_CHECK_CONTROLPLANE))
+		vty_out(vty, " neighbor %s bfd check-control-plane-failure\n", addr);
 }
 
 /*
@@ -644,6 +672,73 @@ DEFUN_HIDDEN (neighbor_bfd_type,
 	return CMD_SUCCESS;
 }
 
+static int bgp_bfd_set_check_controlplane_failure_peer(struct vty *vty, struct peer *peer,
+						       const char *no)
+{
+	struct bfd_info *bfd_info;
+
+	if (!peer->bfd_info) {
+		if (no)
+			return CMD_SUCCESS;
+		vty_out(vty, "%% Specify bfd command first\n");
+		return CMD_WARNING_CONFIG_FAILED;
+	}
+	bfd_info = (struct bfd_info *)peer->bfd_info;
+	if (!no) {
+		if (!CHECK_FLAG(bfd_info->flags, BFD_FLAG_BFD_CHECK_CONTROLPLANE)) {
+			SET_FLAG(bfd_info->flags,  BFD_FLAG_BFD_CHECK_CONTROLPLANE);
+			bgp_bfd_update_peer(peer);
+		}
+	} else {
+		if (CHECK_FLAG(bfd_info->flags, BFD_FLAG_BFD_CHECK_CONTROLPLANE)) {
+			UNSET_FLAG(bfd_info->flags,  BFD_FLAG_BFD_CHECK_CONTROLPLANE);
+			bgp_bfd_update_peer(peer);
+		}
+	}
+	return CMD_SUCCESS;
+}
+
+
+DEFUN (neighbor_bfd_check_controlplane_failure,
+       neighbor_bfd_check_controlplane_failure_cmd,
+       "[no] neighbor <A.B.C.D|X:X::X:X|WORD> bfd check-control-plane-failure",
+       NO_STR
+       NEIGHBOR_STR
+       NEIGHBOR_ADDR_STR2
+       "BFD support\n"
+       "Link dataplane status with BGP controlplane\n")
+{
+	const char *no = strmatch(argv[0]->text, "no") ? "no" : NULL;
+	int idx_peer = 0;
+	struct peer *peer;
+	struct peer_group *group;
+	struct listnode *node, *nnode;
+	int ret = CMD_SUCCESS;
+
+	if (no)
+		idx_peer = 2;
+	else
+		idx_peer = 1;
+	peer = peer_and_group_lookup_vty(vty, argv[idx_peer]->arg);
+	if (!peer) {
+		vty_out(vty, "%% Specify remote-as or peer-group commands first\n");
+		return CMD_WARNING_CONFIG_FAILED;
+	}
+	if (!peer->bfd_info) {
+		if (no)
+			return CMD_SUCCESS;
+		vty_out(vty, "%% Specify bfd command first\n");
+		return CMD_WARNING_CONFIG_FAILED;
+	}
+	if (CHECK_FLAG(peer->sflags, PEER_STATUS_GROUP)) {
+		group = peer->group;
+		for (ALL_LIST_ELEMENTS(group->peer, node, nnode, peer))
+			ret = bgp_bfd_set_check_controlplane_failure_peer(vty, peer, no);
+	} else
+		ret = bgp_bfd_set_check_controlplane_failure_peer(vty, peer, no);
+	return ret;
+ }
+
 DEFUN (no_neighbor_bfd,
        no_neighbor_bfd_cmd,
 #if HAVE_BFDD > 0
@@ -718,6 +813,7 @@ void bgp_bfd_init(void)
 	install_element(BGP_NODE, &neighbor_bfd_cmd);
 	install_element(BGP_NODE, &neighbor_bfd_param_cmd);
 	install_element(BGP_NODE, &neighbor_bfd_type_cmd);
+	install_element(BGP_NODE, &neighbor_bfd_check_controlplane_failure_cmd);
 	install_element(BGP_NODE, &no_neighbor_bfd_cmd);
 	install_element(BGP_NODE, &no_neighbor_bfd_type_cmd);
 }
diff --git a/bgpd/bgp_fsm.c b/bgpd/bgp_fsm.c
index 9e37a6018..12ae1f841 100644
--- a/bgpd/bgp_fsm.c
+++ b/bgpd/bgp_fsm.c
@@ -1115,8 +1115,6 @@ int bgp_stop(struct peer *peer)
 
 		/* Reset peer synctime */
 		peer->synctime = 0;
-
-		bgp_bfd_deregister_peer(peer);
 	}
 
 	/* stop keepalives */
diff --git a/doc/user/bfd.rst b/doc/user/bfd.rst
index a7c5cf28b..33bc77049 100644
--- a/doc/user/bfd.rst
+++ b/doc/user/bfd.rst
@@ -174,6 +174,21 @@ The following commands are available inside the BGP configuration node.
 
    Removes any notification registration for this neighbor.
 
+.. index:: neighbor <A.B.C.D|X:X::X:X|WORD> bfd check-control-plane-failure
+.. clicmd:: neighbor <A.B.C.D|X:X::X:X|WORD> bfd check-control-plane-failure
+
+   Allow to write CBIT independence in BFD outgoing packets. Also allow to
+   read both C-BIT value of BFD and lookup BGP peer status. This command is
+   useful when a BFD down event is caught, while the BGP peer requested that
+   local BGP keeps the remote BGP entries as staled if such issue is detected.
+   This is the case when graceful restart is enabled, and it is wished to
+   ignore the BD event while waiting for the remote router to restart.
+
+.. index:: no neighbor <A.B.C.D|X:X::X:X|WORD> bfd check-control-plane-failure
+.. clicmd:: no neighbor <A.B.C.D|X:X::X:X|WORD> bfd check-control-plane-failure
+
+   Disallow to write CBIT independence in BFD outgoing packets. Also disallow
+   to ignore BFD down notification. This is the default behaviour.
 
 .. _bfd-ospf-peer-config:
 
diff --git a/isisd/isis_bfd.c b/isisd/isis_bfd.c
index fccef0169..fa89c8004 100644
--- a/isisd/isis_bfd.c
+++ b/isisd/isis_bfd.c
@@ -98,7 +98,8 @@ static int isis_bfd_interface_dest_update(ZAPI_CALLBACK_ARGS)
 	struct prefix dst_ip;
 	int status;
 
-	ifp = bfd_get_peer_info(zclient->ibuf, &dst_ip, NULL, &status, vrf_id);
+	ifp = bfd_get_peer_info(zclient->ibuf, &dst_ip, NULL, &status,
+				NULL, vrf_id);
 	if (!ifp || dst_ip.family != AF_INET)
 		return 0;
 
@@ -217,6 +218,7 @@ static void bfd_handle_adj_down(struct isis_adjacency *adj)
 			 adj->circuit->interface->name,
 			 0, /* ttl */
 			 0, /* multihop */
+			 1, /* control plane independent bit is on */
 			 ZEBRA_BFD_DEST_DEREGISTER,
 			 0, /* set_flag */
 			 VRF_DEFAULT);
@@ -258,6 +260,7 @@ static void bfd_handle_adj_up(struct isis_adjacency *adj, int command)
 			 circuit->interface->name,
 			 0, /* ttl */
 			 0, /* multihop */
+			 1, /* control plane independent bit is on */
 			 command,
 			 0, /* set flag */
 			 VRF_DEFAULT);
diff --git a/lib/bfd.c b/lib/bfd.c
index a8956c315..00dbd1b3d 100644
--- a/lib/bfd.c
+++ b/lib/bfd.c
@@ -127,8 +127,8 @@ void bfd_set_param(struct bfd_info **bfd_info, uint32_t min_rx, uint32_t min_tx,
  */
 void bfd_peer_sendmsg(struct zclient *zclient, struct bfd_info *bfd_info,
 		      int family, void *dst_ip, void *src_ip, char *if_name,
-		      int ttl, int multihop, int command, int set_flag,
-		      vrf_id_t vrf_id)
+		      int ttl, int multihop, int cbit, int command,
+		      int set_flag, vrf_id_t vrf_id)
 {
 	struct stream *s;
 	int ret;
@@ -208,6 +208,11 @@ void bfd_peer_sendmsg(struct zclient *zclient, struct bfd_info *bfd_info,
 			stream_putc(s, 0);
 		}
 	}
+	/* cbit */
+	if (cbit)
+		stream_putc(s, 1);
+	else
+		stream_putc(s, 0);
 
 	stream_putw_at(s, 0, stream_get_endp(s));
 
@@ -253,11 +258,13 @@ const char *bfd_get_command_dbg_str(int command)
  */
 struct interface *bfd_get_peer_info(struct stream *s, struct prefix *dp,
 				    struct prefix *sp, int *status,
+				    int *remote_cbit,
 				    vrf_id_t vrf_id)
 {
 	unsigned int ifindex;
 	struct interface *ifp = NULL;
 	int plen;
+	int local_remote_cbit;
 
 	/* Get interface index. */
 	ifindex = stream_getl(s);
@@ -292,6 +299,9 @@ struct interface *bfd_get_peer_info(struct stream *s, struct prefix *dp,
 		stream_get(&sp->u.prefix, s, plen);
 		sp->prefixlen = stream_getc(s);
 	}
+	local_remote_cbit = stream_getc(s);
+	if (remote_cbit)
+		*remote_cbit = local_remote_cbit;
 	return ifp;
 }
 
diff --git a/lib/bfd.h b/lib/bfd.h
index d02110a99..e4781f4ea 100644
--- a/lib/bfd.h
+++ b/lib/bfd.h
@@ -48,6 +48,8 @@ struct bfd_gbl {
 #define BFD_FLAG_PARAM_CFG (1 << 0) /* parameters have been configured */
 #define BFD_FLAG_BFD_REG   (1 << 1) /* Peer registered with BFD */
 #define BFD_FLAG_BFD_TYPE_MULTIHOP (1 << 2) /* Peer registered with BFD as multihop */
+#define BFD_FLAG_BFD_CBIT_ON (1 << 3) /* Peer registered with CBIT set to on */
+#define BFD_FLAG_BFD_CHECK_CONTROLPLANE (1 << 4) /* BFD and controlplane daemon are linked */
 
 #define BFD_STATUS_UNKNOWN (1 << 0) /* BFD session status never received */
 #define BFD_STATUS_DOWN    (1 << 1) /* BFD session status is down */
@@ -83,13 +85,14 @@ extern void bfd_set_param(struct bfd_info **bfd_info, uint32_t min_rx,
 			  int *command);
 extern void bfd_peer_sendmsg(struct zclient *zclient, struct bfd_info *bfd_info,
 			     int family, void *dst_ip, void *src_ip,
-			     char *if_name, int ttl, int multihop, int command,
-			     int set_flag, vrf_id_t vrf_id);
+			     char *if_name, int ttl, int multihop, int cbit,
+			     int command, int set_flag, vrf_id_t vrf_id);
 
 extern const char *bfd_get_command_dbg_str(int command);
 
 extern struct interface *bfd_get_peer_info(struct stream *s, struct prefix *dp,
 					   struct prefix *sp, int *status,
+					   int *remote_cbit,
 					   vrf_id_t vrf_id);
 
 const char *bfd_get_status_str(int status);
diff --git a/ospf6d/ospf6_bfd.c b/ospf6d/ospf6_bfd.c
index 7a26af1f0..f0500601b 100644
--- a/ospf6d/ospf6_bfd.c
+++ b/ospf6d/ospf6_bfd.c
@@ -74,6 +74,7 @@ void ospf6_bfd_reg_dereg_nbr(struct ospf6_neighbor *on, int command)
 	struct interface *ifp = oi->interface;
 	struct bfd_info *bfd_info;
 	char src[64];
+	int cbit;
 
 	if (!oi->bfd_info || !on->bfd_info)
 		return;
@@ -85,9 +86,11 @@ void ospf6_bfd_reg_dereg_nbr(struct ospf6_neighbor *on, int command)
 			   bfd_get_command_dbg_str(command), src);
 	}
 
+	cbit = CHECK_FLAG(bfd_info->flags, BFD_FLAG_BFD_CBIT_ON);
+
 	bfd_peer_sendmsg(zclient, bfd_info, AF_INET6, &on->linklocal_addr,
-			 on->ospf6_if->linklocal_addr, ifp->name, 0, 0, command,
-			 0, VRF_DEFAULT);
+			 on->ospf6_if->linklocal_addr, ifp->name, 0, 0,
+			 cbit, command, 0, VRF_DEFAULT);
 
 	if (command == ZEBRA_BFD_DEST_DEREGISTER)
 		bfd_info_free((struct bfd_info **)&on->bfd_info);
@@ -195,7 +198,8 @@ static int ospf6_bfd_interface_dest_update(ZAPI_CALLBACK_ARGS)
 	struct bfd_info *bfd_info;
 	struct timeval tv;
 
-	ifp = bfd_get_peer_info(zclient->ibuf, &dp, &sp, &status, vrf_id);
+	ifp = bfd_get_peer_info(zclient->ibuf, &dp, &sp, &status,
+				NULL, vrf_id);
 
 	if ((ifp == NULL) || (dp.family != AF_INET6))
 		return 0;
diff --git a/ospfd/ospf_bfd.c b/ospfd/ospf_bfd.c
index c8ad6d04f..a17975270 100644
--- a/ospfd/ospf_bfd.c
+++ b/ospfd/ospf_bfd.c
@@ -65,6 +65,7 @@ static void ospf_bfd_reg_dereg_nbr(struct ospf_neighbor *nbr, int command)
 	struct interface *ifp = oi->ifp;
 	struct ospf_if_params *params;
 	struct bfd_info *bfd_info;
+	int cbit;
 
 	/* Check if BFD is enabled */
 	params = IF_DEF_PARAMS(ifp);
@@ -80,8 +81,10 @@ static void ospf_bfd_reg_dereg_nbr(struct ospf_neighbor *nbr, int command)
 			   inet_ntoa(nbr->src),
 			   ospf_vrf_id_to_name(oi->ospf->vrf_id));
 
+	cbit = CHECK_FLAG(bfd_info->flags, BFD_FLAG_BFD_CBIT_ON);
+
 	bfd_peer_sendmsg(zclient, bfd_info, AF_INET, &nbr->src, NULL, ifp->name,
-			 0, 0, command, 0, oi->ospf->vrf_id);
+			 0, 0, cbit, command, 0, oi->ospf->vrf_id);
 }
 
 /*
@@ -207,7 +210,8 @@ static int ospf_bfd_interface_dest_update(ZAPI_CALLBACK_ARGS)
 	struct bfd_info *bfd_info;
 	struct timeval tv;
 
-	ifp = bfd_get_peer_info(zclient->ibuf, &p, NULL, &status, vrf_id);
+	ifp = bfd_get_peer_info(zclient->ibuf, &p, NULL, &status,
+				NULL, vrf_id);
 
 	if ((ifp == NULL) || (p.family != AF_INET))
 		return 0;
diff --git a/pimd/pim_bfd.c b/pimd/pim_bfd.c
index 300261e5a..87d0f9fa2 100644
--- a/pimd/pim_bfd.c
+++ b/pimd/pim_bfd.c
@@ -111,6 +111,7 @@ static void pim_bfd_reg_dereg_nbr(struct pim_neighbor *nbr, int command)
 	struct pim_interface *pim_ifp = NULL;
 	struct bfd_info *bfd_info = NULL;
 	struct zclient *zclient = NULL;
+	int cbit;
 
 	zclient = pim_zebra_zclient_get();
 
@@ -127,8 +128,12 @@ static void pim_bfd_reg_dereg_nbr(struct pim_neighbor *nbr, int command)
 		zlog_debug("%s Nbr %s %s with BFD", __PRETTY_FUNCTION__, str,
 			   bfd_get_command_dbg_str(command));
 	}
+
+	cbit = CHECK_FLAG(bfd_info->flags, BFD_FLAG_BFD_CBIT_ON);
+
 	bfd_peer_sendmsg(zclient, bfd_info, AF_INET, &nbr->source_addr, NULL,
-			 nbr->interface->name, 0, 0, command, 0, VRF_DEFAULT);
+			 nbr->interface->name, 0, 0, cbit,
+			 command, 0, VRF_DEFAULT);
 }
 
 /*
@@ -222,7 +227,8 @@ static int pim_bfd_interface_dest_update(ZAPI_CALLBACK_ARGS)
 	struct listnode *neigh_nextnode = NULL;
 	struct pim_neighbor *neigh = NULL;
 
-	ifp = bfd_get_peer_info(zclient->ibuf, &p, NULL, &status, vrf_id);
+	ifp = bfd_get_peer_info(zclient->ibuf, &p, NULL, &status,
+				NULL, vrf_id);
 
 	if ((ifp == NULL) || (p.family != AF_INET))
 		return 0;
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/__init__.py b/tests/topotests/bfd-bgp-cbit-topo3/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/__init__.py
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r1/bgp_ipv6_routes_down.json b/tests/topotests/bfd-bgp-cbit-topo3/r1/bgp_ipv6_routes_down.json
new file mode 100644
index 000000000..54ae57f7b
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r1/bgp_ipv6_routes_down.json
@@ -0,0 +1,103 @@
+{
+    "vrfId": 0,
+    "vrfName": "default",
+    "routerId": "10.254.254.1",
+    "localAS": 101,
+    "routes":
+    {
+        "2001:db8:6::/64": [
+            {
+                "stale": true,
+                "valid": true,
+                "bestpath": true,
+                "pathFrom": "external",
+                "prefix": "2001:db8:6::",
+                "prefixLen": 64,
+                "network": "2001:db8:6::\/64",
+                "med": 0,
+                "metric": 0,
+                "weight": 0,
+                "peerId": "2001:db8:4::1",
+                "origin": "IGP",
+                "nexthops": [
+                    { "ip": "2001:db8:4::1",
+                      "afi": "ipv6",
+                      "scope": "global",
+                      "used": true
+                    }
+                ]
+            }
+        ],
+        "2001:db8:7::/64": [
+            {
+                "stale": true,
+                "valid": true,
+                "bestpath": true,
+                "pathFrom": "external",
+                "prefix": "2001:db8:7::",
+                "prefixLen": 64, "network":
+                "2001:db8:7::\/64",
+                "med": 0,
+                "metric": 0,
+                "weight": 0,
+                "peerId": "2001:db8:4::1",
+                "origin": "IGP",
+                "nexthops": [
+                    {
+                        "ip": "2001:db8:4::1",
+                        "afi": "ipv6",
+                        "scope": "global",
+                        "used": true
+                    }
+                ]
+            }
+        ],
+        "2001:db8:8::/64": [
+            {
+                "valid": true,
+                "bestpath": true,
+                "pathFrom": "external",
+                "prefix": "2001:db8:8::",
+                "prefixLen": 64,
+                "network": "2001:db8:8::\/64",
+                "med": 0,
+                "metric": 0,
+              "weight": 32768,
+                "peerId": "(unspec)",
+                "origin": "IGP",
+                "nexthops": [
+                    {
+                        "ip": "::",
+                        "afi": "ipv6",
+                        "scope": "global",
+                        "used": true
+                    }
+                ]
+            }
+        ],
+        "2001:db8:9::/64": [
+            {
+                "valid": true,
+                "bestpath": true,
+                "pathFrom": "external",
+                "prefix": "2001:db8:9::",
+                "prefixLen": 64,
+                "network": "2001:db8:9::\/64",
+                "med": 0,
+                "metric": 0,
+                "weight": 32768,
+                "peerId": "(unspec)",
+                "origin": "IGP",
+                "nexthops": [
+                    {
+                        "ip": "::",
+                        "afi": "ipv6",
+                        "scope": "global",
+                        "used": true
+                    }
+                ]
+            }
+        ]
+    }
+}
+
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r1/bgpd.conf b/tests/topotests/bfd-bgp-cbit-topo3/r1/bgpd.conf
new file mode 100644
index 000000000..fa6d60a8f
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r1/bgpd.conf
@@ -0,0 +1,20 @@
+debug bgp neighbor-events
+router bgp 101
+ bgp router-id 10.254.254.1
+ timers bgp 8 24
+ bgp graceful-restart
+ neighbor 2001:db8:4::1 remote-as 102
+ neighbor 2001:db8:4::1 remote-as external
+ neighbor 2001:db8:4::1 bfd
+ neighbor 2001:db8:4::1 bfd check-control-plane-failure
+ neighbor 2001:db8:4::1 update-source 2001:db8:1::1
+ neighbor 2001:db8:4::1 ebgp-multihop 5
+ address-family ipv4 unicast
+  no neighbor 2001:db8:4::1 activate
+ exit-address-family
+ address-family ipv6 unicast
+  network 2001:db8:8::/64
+  network 2001:db8:9::/64 
+  neighbor 2001:db8:4::1 activate
+ exit-address-family
+!
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r1/ipv6_routes.json b/tests/topotests/bfd-bgp-cbit-topo3/r1/ipv6_routes.json
new file mode 100644
index 000000000..8eea18328
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r1/ipv6_routes.json
@@ -0,0 +1,80 @@
+{
+  "2001:db8:1::/64": [{
+        "distance": 0,
+        "protocol": "connected",
+        "metric": 0,
+        "selected": true,
+        "destSelected": true,
+        "prefix": "2001:db8:1::/64",
+        "nexthops": [{
+                "directlyConnected": true,
+                "interfaceName": "r1-eth0",
+                "fib": true,
+                "flags": 3,
+                "active": true
+            }
+        ]
+    }
+  ],
+  "2001:db8:4::/64": [{
+        "distance": 1,
+        "protocol": "static",
+        "metric": 0,
+        "selected": true,
+        "destSelected": true,
+        "prefix": "2001:db8:4::/64",
+        "nexthops": [{
+                "interfaceName": "r1-eth0",
+                "fib": true,
+                "flags": 3,
+                "active": true,
+                "afi": "ipv6"
+            }
+        ]
+    }
+  ],
+  "2001:db8:6::/64": [{
+        "distance": 20,
+        "protocol": "bgp",
+        "metric": 0,
+        "selected": true,
+        "destSelected": true,
+        "prefix": "2001:db8:6::/64",
+        "nexthops": [{
+                "ip":"2001:db8:4::1",
+                "active": true,
+                "afi": "ipv6",
+                "recursive":true
+            },
+            {
+                "fib":true,
+                "ip":"2001:db8:1::2",
+                "afi": "ipv6",
+                "interfaceName": "r1-eth0"
+            }
+        ]
+    }
+  ],
+  "2001:db8:7::/64": [{
+        "distance": 20,
+        "protocol": "bgp",
+        "metric": 0,
+        "selected": true,
+        "destSelected": true,
+        "prefix": "2001:db8:7::/64",
+        "nexthops": [{
+                "ip":"2001:db8:4::1",
+                "active": true,
+                "afi": "ipv6",
+                "recursive": true
+            },
+            {
+                "fib":true,
+                "ip":"2001:db8:1::2",
+                "afi": "ipv6",
+                "interfaceName":"r1-eth0"
+            }
+        ]
+    }
+  ]
+}
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r1/peers.json b/tests/topotests/bfd-bgp-cbit-topo3/r1/peers.json
new file mode 100644
index 000000000..d1927ae49
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r1/peers.json
@@ -0,0 +1,16 @@
+[
+    {
+        "multihop":true,
+        "peer":"2001:db8:4::1",
+        "local":"2001:db8:1::1",
+        "status":"up",
+        "diagnostic":"ok",
+        "remote-diagnostic":"ok",
+        "receive-interval":300,
+        "transmit-interval":300,
+        "echo-interval":0,
+        "remote-receive-interval":300,
+        "remote-transmit-interval":300,
+        "remote-echo-interval":50
+    }
+]
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r1/peers_down.json b/tests/topotests/bfd-bgp-cbit-topo3/r1/peers_down.json
new file mode 100644
index 000000000..25b47f18e
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r1/peers_down.json
@@ -0,0 +1,14 @@
+[
+    {
+        "multihop":true,
+        "peer":"2001:db8:4::1",
+        "local":"2001:db8:1::1",
+        "status":"up",
+        "receive-interval":300,
+        "transmit-interval":300,
+        "echo-interval":0,
+        "remote-receive-interval":300,
+        "remote-transmit-interval":300,
+        "remote-echo-interval":50
+    }
+]
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r1/zebra.conf b/tests/topotests/bfd-bgp-cbit-topo3/r1/zebra.conf
new file mode 100644
index 000000000..3a30cd42f
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r1/zebra.conf
@@ -0,0 +1,8 @@
+interface lo
+ ip address 10.254.254.1/32
+!
+interface r1-eth0
+ ipv6 address 2001:db8:1::1/64
+!
+ipv6 route 2001:db8:4::/64 2001:db8:1::2
+
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r2/zebra.conf b/tests/topotests/bfd-bgp-cbit-topo3/r2/zebra.conf
new file mode 100644
index 000000000..0f70be1bd
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r2/zebra.conf
@@ -0,0 +1,9 @@
+ip forwarding
+ipv6 forwarding
+!
+interface r2-eth0
+ ipv6 address 2001:db8:1::2/64
+!
+interface r2-eth1
+ ipv6 address 2001:db8:4::2/64
+!
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r3/bgp_ipv6_routes_down.json b/tests/topotests/bfd-bgp-cbit-topo3/r3/bgp_ipv6_routes_down.json
new file mode 100644
index 000000000..a3bb22250
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r3/bgp_ipv6_routes_down.json
@@ -0,0 +1,55 @@
+{
+    "vrfId": 0,
+    "vrfName": "default",
+    "routerId": "10.254.254.3",
+    "localAS": 102,
+    "routes":
+    {
+        "2001:db8:6::/64": [
+            {
+                "valid": true,
+                "bestpath": true,
+                "pathFrom": "external",
+                "prefix": "2001:db8:6::",
+                "prefixLen": 64,
+                "network": "2001:db8:6::\/64",
+                "med": 0,
+                "metric": 0,
+                "weight": 32768,
+                "peerId": "(unspec)",
+                "origin": "IGP",
+                "nexthops": [
+                    {
+                        "ip": "::",
+                        "afi": "ipv6",
+                        "scope": "global",
+                        "used": true
+                    }
+                ]
+            }
+        ],
+        "2001:db8:7::/64": [
+            {
+                "valid": true,
+                "bestpath": true,
+                "pathFrom": "external",
+                "prefix": "2001:db8:7::",
+                "prefixLen": 64,
+                "network": "2001:db8:7::\/64",
+                "med": 0,
+                "metric": 0,
+                "weight": 32768,
+                "peerId": "(unspec)",
+                "origin": "IGP",
+                "nexthops": [
+                    {
+                        "ip": "::",
+                        "afi": "ipv6",
+                        "scope": "global",
+                        "used": true
+                    }
+                ]
+            }
+        ]
+    }
+}
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r3/bgpd.conf b/tests/topotests/bfd-bgp-cbit-topo3/r3/bgpd.conf
new file mode 100644
index 000000000..ea5334029
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r3/bgpd.conf
@@ -0,0 +1,25 @@
+debug bgp neighbor-events
+router bgp 102
+ bgp router-id 10.254.254.3
+ timers bgp 20 60
+ bgp graceful-restart
+ ! simulate NSF machine
+ bgp graceful-restart preserve-fw-state
+ bgp graceful-restart stalepath-time 900
+ bgp graceful-restart restart-time 900
+ neighbor 2001:db8:1::1 remote-as 101
+ neighbor 2001:db8:1::1 remote-as external
+ neighbor 2001:db8:1::1 update-source 2001:db8:4::1
+ neighbor 2001:db8:1::1 bfd
+ neighbor 2001:db8:1::1 ebgp-multihop 5
+ !
+ address-family ipv4 unicast
+  no neighbor 2001:db8:1::1 activate
+ exit-address-family
+ !
+ address-family ipv6 unicast
+  neighbor 2001:db8:1::1 activate
+  network 2001:db8:6::/64
+  network 2001:db8:7::/64
+ exit-address-family
+!
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r3/ipv6_routes.json b/tests/topotests/bfd-bgp-cbit-topo3/r3/ipv6_routes.json
new file mode 100644
index 000000000..09808cc09
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r3/ipv6_routes.json
@@ -0,0 +1,80 @@
+{
+  "2001:db8:1::/64": [{
+      "distance": 1,
+      "protocol": "static",
+      "metric": 0,
+      "selected": true,
+      "destSelected": true,
+      "prefix": "2001:db8:1::/64",
+      "nexthops": [{
+          "interfaceName": "r3-eth0",
+          "fib": true,
+          "flags": 3,
+          "active": true,
+          "afi": "ipv6"
+        }
+      ]
+    }
+  ],
+  "2001:db8:4::/64": [{
+      "distance": 0,
+      "protocol": "connected",
+      "metric": 0,
+      "selected": true,
+      "destSelected": true,
+      "prefix": "2001:db8:4::/64",
+      "nexthops": [{
+          "directlyConnected": true,
+          "interfaceName": "r3-eth0",
+          "fib": true,
+          "flags": 3,
+          "active": true
+        }
+      ]
+    }
+  ],
+  "2001:db8:8::/64": [{
+      "distance": 20,
+      "protocol": "bgp",
+      "metric": 0,
+      "selected": true,
+      "destSelected": true,
+      "prefix": "2001:db8:8::/64",
+      "nexthops": [{
+          "ip":"2001:db8:1::1",
+          "active": true,
+          "afi": "ipv6",
+          "recursive":true
+        },
+        {
+          "fib":true,
+          "ip":"2001:db8:4::2",
+          "afi": "ipv6",
+          "interfaceName":"r3-eth0"
+        }
+      ]
+    }
+  ],
+  "2001:db8:9::/64": [{
+      "distance": 20,
+      "protocol": "bgp",
+      "metric": 0,
+      "selected": true,
+      "destSelected": true,
+      "prefix": "2001:db8:9::/64",
+      "nexthops": [{
+          "ip":"2001:db8:1::1",
+          "active": true,
+          "afi": "ipv6",
+          "recursive":true
+        },
+        {
+          "fib":true,
+          "ip":"2001:db8:4::2",
+          "afi": "ipv6",
+          "interfaceName":"r3-eth0"
+        }
+      ]
+    }
+  ]
+}
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r3/peers.json b/tests/topotests/bfd-bgp-cbit-topo3/r3/peers.json
new file mode 100644
index 000000000..5193f2a6e
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r3/peers.json
@@ -0,0 +1,16 @@
+[
+    {
+        "multihop":true,
+        "peer":"2001:db8:1::1",
+        "local":"2001:db8:4::1",
+        "status":"up",
+        "diagnostic":"ok",
+        "remote-diagnostic":"ok",
+        "receive-interval":300,
+        "transmit-interval":300,
+        "echo-interval":0,
+        "remote-receive-interval":300,
+        "remote-transmit-interval":300,
+        "remote-echo-interval":50
+    }
+]
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r3/peers_down.json b/tests/topotests/bfd-bgp-cbit-topo3/r3/peers_down.json
new file mode 100644
index 000000000..9e4bd2633
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r3/peers_down.json
@@ -0,0 +1,14 @@
+[
+    {
+        "multihop":true,
+        "peer":"2001:db8:1::1",
+        "local":"2001:db8:4::1",
+        "status":"down",
+        "receive-interval":300,
+        "transmit-interval":300,
+        "echo-interval":0,
+        "remote-receive-interval":300,
+        "remote-transmit-interval":300,
+        "remote-echo-interval":50
+    }
+]
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/r3/zebra.conf b/tests/topotests/bfd-bgp-cbit-topo3/r3/zebra.conf
new file mode 100644
index 000000000..7759251dc
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/r3/zebra.conf
@@ -0,0 +1,7 @@
+interface lo
+ ip address 10.254.254.3/32
+!
+interface r3-eth0
+ ipv6 address 2001:db8:4::1/64
+!
+ipv6 route 2001:db8:1::/64 2001:db8:4::2
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/test_bfd_bgp_cbit_topo3.dot b/tests/topotests/bfd-bgp-cbit-topo3/test_bfd_bgp_cbit_topo3.dot
new file mode 100644
index 000000000..270de829c
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/test_bfd_bgp_cbit_topo3.dot
@@ -0,0 +1,58 @@
+## Color coding:
+#########################
+##  Main FRR: #f08080  red
+##  Switches: #d0e0d0  gray
+##  RIP:      #19e3d9  Cyan
+##  RIPng:    #fcb314  dark yellow
+##  OSPFv2:   #32b835  Green
+##  OSPFv3:   #19e3d9  Cyan
+##  ISIS IPv4 #fcb314  dark yellow
+##  ISIS IPv6 #9a81ec  purple
+##  BGP IPv4  #eee3d3  beige
+##  BGP IPv6  #fdff00  yellow
+##### Colors (see http://www.color-hex.com/)
+
+graph template {
+  label="bfd-topo2";
+
+  # Routers
+  r1 [
+    shape=doubleoctagon,
+    label="r1",
+    fillcolor="#f08080",
+    style=filled,
+  ];
+  r2 [
+    shape=doubleoctagon
+    label="r2",
+    fillcolor="#f08080",
+    style=filled,
+  ];
+  r3 [
+    shape=doubleoctagon
+    label="r4",
+    fillcolor="#f08080",
+    style=filled,
+  ];
+
+  # Switches
+  sw1 [
+    shape=oval,
+    label="sw1\n2001:db8:1::/64",
+    fillcolor="#d0e0d0",
+    style=filled,
+  ];
+  sw2 [
+    shape=oval,
+    label="sw2\n10.0.3.0/24",
+    fillcolor="#d0e0d0",
+    style=filled,
+  ];
+
+  # Connections
+  r1 -- sw1 [label="eth0"];
+  r2 -- sw1 [label="eth0"];
+
+  r2 -- sw2 [label="eth1"];
+  r3 -- sw2 [label="eth0"];
+}
diff --git a/tests/topotests/bfd-bgp-cbit-topo3/test_bfd_bgp_cbit_topo3.py b/tests/topotests/bfd-bgp-cbit-topo3/test_bfd_bgp_cbit_topo3.py
new file mode 100755
index 000000000..59858d6fd
--- /dev/null
+++ b/tests/topotests/bfd-bgp-cbit-topo3/test_bfd_bgp_cbit_topo3.py
@@ -0,0 +1,248 @@
+#!/usr/bin/env python
+
+#
+# test_bfd_bgp_cbit_topo3.py
+#
+# Copyright (c) 2019 6WIND
+#
+# Permission to use, copy, modify, and/or distribute this software
+# for any purpose with or without fee is hereby granted, provided
+# that the above copyright notice and this permission notice appear
+# in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND NETDEF DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NETDEF BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY
+# DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+# WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+# OF THIS SOFTWARE.
+#
+
+"""
+test_bfd_bgp_cbit_topo3.py: Test the FRR/Quagga BFD daemon with multihop and BGP
+unnumbered.
+"""
+
+import os
+import sys
+import json
+from functools import partial
+import pytest
+
+# Save the Current Working Directory to find configuration files.
+CWD = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(CWD, '../'))
+
+# pylint: disable=C0413
+# Import topogen and topotest helpers
+from lib import topotest
+from lib.topogen import Topogen, TopoRouter, get_topogen
+from lib.topolog import logger
+
+# Required to instantiate the topology builder class.
+from mininet.topo import Topo
+
+class BFDTopo(Topo):
+    "Test topology builder"
+    def build(self, *_args, **_opts):
+        "Build function"
+        tgen = get_topogen(self)
+
+        # Create 4 routers.
+        for routern in range(1, 4):
+            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'])
+
+def setup_module(mod):
+    "Sets up the pytest environment"
+    tgen = Topogen(BFDTopo, mod.__name__)
+    tgen.start_topology()
+
+    router_list = tgen.routers()
+
+    for rname, router in router_list.iteritems():
+        router.load_config(
+            TopoRouter.RD_ZEBRA,
+            os.path.join(CWD, '{}/zebra.conf'.format(rname)),
+        )
+        router.load_config(
+            TopoRouter.RD_BFD,
+            os.path.join(CWD, '{}/bfdd.conf'.format(rname))
+        )
+        router.load_config(
+            TopoRouter.RD_BGP,
+            os.path.join(CWD, '{}/bgpd.conf'.format(rname))
+        )
+
+    # Initialize all routers.
+    tgen.start_router()
+
+    # Verify that we are using the proper version and that the BFD
+    # daemon exists.
+    for router in router_list.values():
+        # Check for Version
+        if router.has_version('<', '5.1'):
+            tgen.set_error('Unsupported FRR version')
+            break
+
+def teardown_module(_mod):
+    "Teardown the pytest environment"
+    tgen = get_topogen()
+    tgen.stop_topology()
+
+
+def test_protocols_convergence():
+    """
+    Assert that all protocols have converged before checking for the BFD
+    statuses as they depend on it.
+    """
+    tgen = get_topogen()
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    # Check IPv6 routing tables.
+    logger.info("Checking IPv6 routes for convergence")
+    for router in tgen.routers().values():
+        if router.name == 'r2':
+            continue
+        json_file = '{}/{}/ipv6_routes.json'.format(CWD, router.name)
+        if not os.path.isfile(json_file):
+            logger.info('skipping file {}'.format(json_file))
+            continue
+        expected = json.loads(open(json_file).read())
+        test_func = partial(topotest.router_json_cmp,
+                            router, 'show ipv6 route json', expected)
+        _, result = topotest.run_and_expect(test_func, None, count=40,
+                                            wait=0.5)
+        assertmsg = '"{}" JSON output mismatches'.format(router.name)
+        assert result is None, assertmsg
+
+
+def test_bfd_connection():
+    "Assert that the BFD peers can find themselves."
+    tgen = get_topogen()
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    logger.info('waiting for bfd peers to go up')
+    for router in tgen.routers().values():
+        if router.name == 'r2':
+            continue
+        json_file = '{}/{}/peers.json'.format(CWD, router.name)
+        expected = json.loads(open(json_file).read())
+
+        test_func = partial(topotest.router_json_cmp,
+                            router, 'show bfd peers json', expected)
+        _, result = topotest.run_and_expect(test_func, None, count=8, wait=0.5)
+        assertmsg = '"{}" JSON output mismatches'.format(router.name)
+        assert result is None, assertmsg
+
+def test_bfd_loss_intermediate():
+    """
+    Assert that BFD notices the bfd link down failure.
+    but BGP entries should still be present
+    """
+    tgen = get_topogen()
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    logger.info('removing IPv6 address from r2 to simulate loss of connectivity')
+    # Disable r2-eth0 ipv6 address
+    cmd = 'vtysh -c \"configure terminal\" -c \"interface r2-eth1\" -c "no ipv6 address 2001:db8:4::2/64\"'
+    tgen.net['r2'].cmd(cmd)
+ 
+    # Wait the minimum time we can before checking that BGP/BFD
+    # converged.
+    logger.info('waiting for BFD converge down')
+
+    # Check that BGP converged quickly.
+    for router in tgen.routers().values():
+        if router.name == 'r2':
+            continue
+        json_file = '{}/{}/peers_down.json'.format(CWD, router.name)
+        expected = json.loads(open(json_file).read())
+
+        test_func = partial(topotest.router_json_cmp,
+                            router, 'show bfd peers json', expected)
+        _, result = topotest.run_and_expect(test_func, None, count=8, wait=0.5)
+        assertmsg = '"{}" JSON output mismatches'.format(router.name)
+        assert result is None, assertmsg
+
+    logger.info('waiting for BGP entries to become stale')
+    for router in tgen.routers().values():
+        if router.name == 'r2':
+            continue
+        json_file = '{}/{}/bgp_ipv6_routes_down.json'.format(CWD, router.name)
+        expected = json.loads(open(json_file).read())
+
+        test_func = partial(topotest.router_json_cmp,
+                            router, 'show bgp ipv6 json', expected)
+        _, result = topotest.run_and_expect(test_func, None, count=50, wait=1)
+        assertmsg = '"{}" JSON output mismatches'.format(router.name)
+        assert result is None, assertmsg
+
+    logger.info("Checking IPv6 routes on r1 should still be present")
+    for router in tgen.routers().values():
+        if router.name == 'r2':
+            continue
+        if router.name == 'r3':
+            continue
+        json_file = '{}/r1/ipv6_routes.json'.format(CWD)
+        expected = json.loads(open(json_file).read())
+        test_func = partial(topotest.router_json_cmp,
+                            router, 'show ipv6 route json', expected)
+        _, result = topotest.run_and_expect(test_func, None, count=30,
+                                            wait=0.5)
+        assertmsg = '"{}" JSON output mismatches'.format(router.name)
+        assert result is None, assertmsg
+
+def test_bfd_comes_back_again():
+    """
+    Assert that BFD notices the bfd link up
+    and that ipv6 entries appear back
+    """
+    tgen = get_topogen()
+    logger.info('re-adding IPv6 address from r2 to simulate connectivity is back')
+    # adds back r2-eth0 ipv6 address
+    cmd = 'vtysh -c \"configure terminal\" -c \"interface r2-eth1\" -c "ipv6 address 2001:db8:4::2/64\"'
+    tgen.net['r2'].cmd(cmd)
+
+    # Wait the minimum time we can before checking that BGP/BFD
+    # converged.
+    logger.info('waiting for BFD to converge up')
+
+    # Check that BGP converged quickly.
+    for router in tgen.routers().values():
+        if router.name == 'r2':
+            continue
+        json_file = '{}/{}/peers.json'.format(CWD, router.name)
+        expected = json.loads(open(json_file).read())
+
+        test_func = partial(topotest.router_json_cmp,
+                            router, 'show bfd peers json', expected)
+        _, result = topotest.run_and_expect(test_func, None, count=8, wait=0.5)
+        assertmsg = '"{}" JSON output mismatches'.format(router.name)
+        assert result is None, assertmsg
+    
+
+def test_memory_leak():
+    "Run the memory leak test and report results."
+    tgen = get_topogen()
+    if not tgen.is_memleak_enabled():
+        pytest.skip('Memory leak test/report is disabled')
+
+    tgen.report_memory_leaks()
+
+
+if __name__ == '__main__':
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))
diff --git a/zebra/zebra_ptm.c b/zebra/zebra_ptm.c
index d3ecd3695..46f138552 100644
--- a/zebra/zebra_ptm.c
+++ b/zebra/zebra_ptm.c
@@ -93,6 +93,7 @@ const char ZEBRA_PTM_BFD_IFNAME_FIELD[] = "ifName";
 const char ZEBRA_PTM_BFD_MAX_HOP_CNT_FIELD[] = "maxHopCnt";
 const char ZEBRA_PTM_BFD_SEND_EVENT[] = "sendEvent";
 const char ZEBRA_PTM_BFD_VRF_NAME_FIELD[] = "vrfName";
+const char ZEBRA_PTM_BFD_CBIT_FIELD[] = "bfdcbit";
 
 static ptm_lib_handle_t *ptm_hdl;
 
@@ -688,6 +689,7 @@ void zebra_ptm_bfd_dst_register(ZAPI_HANDLER_ARGS)
 	char tmp_buf[64];
 	int data_len = ZEBRA_PTM_SEND_MAX_SOCKBUF;
 	unsigned int pid;
+	uint8_t cbit_set;
 
 	if (hdr->command == ZEBRA_BFD_DEST_UPDATE)
 		client->bfd_peer_upd8_cnt++;
@@ -813,6 +815,10 @@ void zebra_ptm_bfd_dst_register(ZAPI_HANDLER_ARGS)
 		ptm_lib_append_msg(ptm_hdl, out_ctxt,
 				   ZEBRA_PTM_BFD_IFNAME_FIELD, if_name);
 	}
+	STREAM_GETC(s, cbit_set);
+	sprintf(tmp_buf, "%d", cbit_set);
+	ptm_lib_append_msg(ptm_hdl, out_ctxt,
+			   ZEBRA_PTM_BFD_CBIT_FIELD, tmp_buf);
 
 	sprintf(tmp_buf, "%d", 1);
 	ptm_lib_append_msg(ptm_hdl, out_ctxt, ZEBRA_PTM_BFD_SEND_EVENT,