Adding upstream version 8.4.4.upstream/8.4.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 845 insertions, 0 deletions

diff --git a/bfdd/control.c b/bfdd/control.c
new file mode 100644
index 0000000..473843f
--- /dev/null
+++ b/bfdd/control.c
@@ -0,0 +1,845 @@
+/*********************************************************************
+ * Copyright 2017-2018 Network Device Education Foundation, Inc. ("NetDEF")
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * control.c: implements the BFD daemon control socket. It will be used
+ * to talk with clients daemon/scripts/consumers.
+ *
+ * Authors
+ * -------
+ * Rafael Zalamena <rzalamena@opensourcerouting.org>
+ */
+
+#include <zebra.h>
+
+#include <sys/un.h>
+
+#include "bfd.h"
+
+/*
+ * Prototypes
+ */
+static int sock_set_nonblock(int fd);
+struct bfd_control_queue *control_queue_new(struct bfd_control_socket *bcs);
+static void control_queue_free(struct bfd_control_socket *bcs,
+			       struct bfd_control_queue *bcq);
+static int control_queue_dequeue(struct bfd_control_socket *bcs);
+static int control_queue_enqueue(struct bfd_control_socket *bcs,
+				 struct bfd_control_msg *bcm);
+static int control_queue_enqueue_first(struct bfd_control_socket *bcs,
+				       struct bfd_control_msg *bcm);
+struct bfd_notify_peer *control_notifypeer_new(struct bfd_control_socket *bcs,
+					       struct bfd_session *bs);
+static void control_notifypeer_free(struct bfd_control_socket *bcs,
+				    struct bfd_notify_peer *bnp);
+struct bfd_notify_peer *control_notifypeer_find(struct bfd_control_socket *bcs,
+						struct bfd_session *bs);
+
+
+struct bfd_control_socket *control_new(int sd);
+static void control_free(struct bfd_control_socket *bcs);
+static void control_reset_buf(struct bfd_control_buffer *bcb);
+static void control_read(struct thread *t);
+static void control_write(struct thread *t);
+
+static void control_handle_request_add(struct bfd_control_socket *bcs,
+				       struct bfd_control_msg *bcm);
+static void control_handle_request_del(struct bfd_control_socket *bcs,
+				       struct bfd_control_msg *bcm);
+static int notify_add_cb(struct bfd_peer_cfg *bpc, void *arg);
+static int notify_del_cb(struct bfd_peer_cfg *bpc, void *arg);
+static void control_handle_notify_add(struct bfd_control_socket *bcs,
+				      struct bfd_control_msg *bcm);
+static void control_handle_notify_del(struct bfd_control_socket *bcs,
+				      struct bfd_control_msg *bcm);
+static void _control_handle_notify(struct hash_bucket *hb, void *arg);
+static void control_handle_notify(struct bfd_control_socket *bcs,
+				  struct bfd_control_msg *bcm);
+static void control_response(struct bfd_control_socket *bcs, uint16_t id,
+			     const char *status, const char *error);
+
+static void _control_notify_config(struct bfd_control_socket *bcs,
+				   const char *op, struct bfd_session *bs);
+static void _control_notify(struct bfd_control_socket *bcs,
+			    struct bfd_session *bs);
+
+
+/*
+ * Functions
+ */
+static int sock_set_nonblock(int fd)
+{
+	int flags;
+
+	flags = fcntl(fd, F_GETFL, 0);
+	if (flags == -1) {
+		zlog_warn("%s: fcntl F_GETFL: %s", __func__, strerror(errno));
+		return -1;
+	}
+
+	flags |= O_NONBLOCK;
+	if (fcntl(fd, F_SETFL, flags) == -1) {
+		zlog_warn("%s: fcntl F_SETFL: %s", __func__, strerror(errno));
+		return -1;
+	}
+
+	return 0;
+}
+
+int control_init(const char *path)
+{
+	int sd;
+	mode_t umval;
+	struct sockaddr_un sun_ = {
+		.sun_family = AF_UNIX,
+		.sun_path = BFDD_CONTROL_SOCKET,
+	};
+
+	if (path)
+		strlcpy(sun_.sun_path, path, sizeof(sun_.sun_path));
+
+	/* Remove previously created sockets. */
+	unlink(sun_.sun_path);
+
+	sd = socket(AF_UNIX, SOCK_STREAM, PF_UNSPEC);
+	if (sd == -1) {
+		zlog_err("%s: socket: %s", __func__, strerror(errno));
+		return -1;
+	}
+
+	umval = umask(0);
+	if (bind(sd, (struct sockaddr *)&sun_, sizeof(sun_)) == -1) {
+		zlog_err("%s: bind: %s", __func__, strerror(errno));
+		close(sd);
+		return -1;
+	}
+	umask(umval);
+
+	if (listen(sd, SOMAXCONN) == -1) {
+		zlog_err("%s: listen: %s", __func__, strerror(errno));
+		close(sd);
+		return -1;
+	}
+
+	sock_set_nonblock(sd);
+
+	bglobal.bg_csock = sd;
+
+	return 0;
+}
+
+void control_shutdown(void)
+{
+	struct bfd_control_socket *bcs;
+
+	thread_cancel(&bglobal.bg_csockev);
+
+	socket_close(&bglobal.bg_csock);
+
+	while (!TAILQ_EMPTY(&bglobal.bg_bcslist)) {
+		bcs = TAILQ_FIRST(&bglobal.bg_bcslist);
+		control_free(bcs);
+	}
+}
+
+void control_accept(struct thread *t)
+{
+	int csock, sd = THREAD_FD(t);
+
+	csock = accept(sd, NULL, 0);
+	if (csock == -1) {
+		zlog_warn("%s: accept: %s", __func__, strerror(errno));
+		return;
+	}
+
+	control_new(csock);
+
+	thread_add_read(master, control_accept, NULL, sd, &bglobal.bg_csockev);
+}
+
+
+/*
+ * Client handling
+ */
+struct bfd_control_socket *control_new(int sd)
+{
+	struct bfd_control_socket *bcs;
+
+	bcs = XCALLOC(MTYPE_BFDD_CONTROL, sizeof(*bcs));
+
+	/* Disable notifications by default. */
+	bcs->bcs_notify = 0;
+
+	bcs->bcs_sd = sd;
+	thread_add_read(master, control_read, bcs, sd, &bcs->bcs_ev);
+
+	TAILQ_INIT(&bcs->bcs_bcqueue);
+	TAILQ_INIT(&bcs->bcs_bnplist);
+	TAILQ_INSERT_TAIL(&bglobal.bg_bcslist, bcs, bcs_entry);
+
+	return bcs;
+}
+
+static void control_free(struct bfd_control_socket *bcs)
+{
+	struct bfd_control_queue *bcq;
+	struct bfd_notify_peer *bnp;
+
+	thread_cancel(&(bcs->bcs_ev));
+	thread_cancel(&(bcs->bcs_outev));
+
+	close(bcs->bcs_sd);
+
+	TAILQ_REMOVE(&bglobal.bg_bcslist, bcs, bcs_entry);
+
+	/* Empty output queue. */
+	while (!TAILQ_EMPTY(&bcs->bcs_bcqueue)) {
+		bcq = TAILQ_FIRST(&bcs->bcs_bcqueue);
+		control_queue_free(bcs, bcq);
+	}
+
+	/* Empty notification list. */
+	while (!TAILQ_EMPTY(&bcs->bcs_bnplist)) {
+		bnp = TAILQ_FIRST(&bcs->bcs_bnplist);
+		control_notifypeer_free(bcs, bnp);
+	}
+
+	control_reset_buf(&bcs->bcs_bin);
+	XFREE(MTYPE_BFDD_CONTROL, bcs);
+}
+
+struct bfd_notify_peer *control_notifypeer_new(struct bfd_control_socket *bcs,
+					       struct bfd_session *bs)
+{
+	struct bfd_notify_peer *bnp;
+
+	bnp = control_notifypeer_find(bcs, bs);
+	if (bnp)
+		return bnp;
+
+	bnp = XCALLOC(MTYPE_BFDD_CONTROL, sizeof(*bnp));
+
+	TAILQ_INSERT_TAIL(&bcs->bcs_bnplist, bnp, bnp_entry);
+	bnp->bnp_bs = bs;
+	bs->refcount++;
+
+	return bnp;
+}
+
+static void control_notifypeer_free(struct bfd_control_socket *bcs,
+				    struct bfd_notify_peer *bnp)
+{
+	TAILQ_REMOVE(&bcs->bcs_bnplist, bnp, bnp_entry);
+	bnp->bnp_bs->refcount--;
+	XFREE(MTYPE_BFDD_CONTROL, bnp);
+}
+
+struct bfd_notify_peer *control_notifypeer_find(struct bfd_control_socket *bcs,
+						struct bfd_session *bs)
+{
+	struct bfd_notify_peer *bnp;
+
+	TAILQ_FOREACH (bnp, &bcs->bcs_bnplist, bnp_entry) {
+		if (bnp->bnp_bs == bs)
+			return bnp;
+	}
+
+	return NULL;
+}
+
+struct bfd_control_queue *control_queue_new(struct bfd_control_socket *bcs)
+{
+	struct bfd_control_queue *bcq;
+
+	bcq = XCALLOC(MTYPE_BFDD_NOTIFICATION, sizeof(*bcq));
+
+	control_reset_buf(&bcq->bcq_bcb);
+	TAILQ_INSERT_TAIL(&bcs->bcs_bcqueue, bcq, bcq_entry);
+
+	return bcq;
+}
+
+static void control_queue_free(struct bfd_control_socket *bcs,
+			       struct bfd_control_queue *bcq)
+{
+	control_reset_buf(&bcq->bcq_bcb);
+	TAILQ_REMOVE(&bcs->bcs_bcqueue, bcq, bcq_entry);
+	XFREE(MTYPE_BFDD_NOTIFICATION, bcq);
+}
+
+static int control_queue_dequeue(struct bfd_control_socket *bcs)
+{
+	struct bfd_control_queue *bcq;
+
+	/* List is empty, nothing to do. */
+	if (TAILQ_EMPTY(&bcs->bcs_bcqueue))
+		goto empty_list;
+
+	bcq = TAILQ_FIRST(&bcs->bcs_bcqueue);
+	control_queue_free(bcs, bcq);
+
+	/* Get the next buffer to send. */
+	if (TAILQ_EMPTY(&bcs->bcs_bcqueue))
+		goto empty_list;
+
+	bcq = TAILQ_FIRST(&bcs->bcs_bcqueue);
+	bcs->bcs_bout = &bcq->bcq_bcb;
+
+	bcs->bcs_outev = NULL;
+	thread_add_write(master, control_write, bcs, bcs->bcs_sd,
+			 &bcs->bcs_outev);
+
+	return 1;
+
+empty_list:
+	thread_cancel(&(bcs->bcs_outev));
+	bcs->bcs_bout = NULL;
+	return 0;
+}
+
+static int control_queue_enqueue(struct bfd_control_socket *bcs,
+				 struct bfd_control_msg *bcm)
+{
+	struct bfd_control_queue *bcq;
+	struct bfd_control_buffer *bcb;
+
+	bcq = control_queue_new(bcs);
+
+	bcb = &bcq->bcq_bcb;
+	bcb->bcb_left = sizeof(struct bfd_control_msg) + ntohl(bcm->bcm_length);
+	bcb->bcb_pos = 0;
+	bcb->bcb_bcm = bcm;
+
+	/* If this is the first item, then dequeue and start using it. */
+	if (bcs->bcs_bout == NULL) {
+		bcs->bcs_bout = bcb;
+
+		/* New messages, active write events. */
+		thread_add_write(master, control_write, bcs, bcs->bcs_sd,
+				 &bcs->bcs_outev);
+	}
+
+	return 0;
+}
+
+static int control_queue_enqueue_first(struct bfd_control_socket *bcs,
+				       struct bfd_control_msg *bcm)
+{
+	struct bfd_control_queue *bcq, *bcqn;
+	struct bfd_control_buffer *bcb;
+
+	/* Enqueue it somewhere. */
+	if (control_queue_enqueue(bcs, bcm) == -1)
+		return -1;
+
+	/*
+	 * The item is either the first or the last. So we must first
+	 * check the best case where the item is already the first.
+	 */
+	bcq = TAILQ_FIRST(&bcs->bcs_bcqueue);
+	bcb = &bcq->bcq_bcb;
+	if (bcm == bcb->bcb_bcm)
+		return 0;
+
+	/*
+	 * The item was not the first, so it is the last. We'll try to
+	 * assign it to the head of the queue, however if there is a
+	 * transfer in progress, then we have to make the item as the
+	 * next one.
+	 *
+	 * Interrupting the transfer of in progress message will cause
+	 * the client to lose track of the message position/data.
+	 */
+	bcqn = TAILQ_LAST(&bcs->bcs_bcqueue, bcqueue);
+	TAILQ_REMOVE(&bcs->bcs_bcqueue, bcqn, bcq_entry);
+	if (bcb->bcb_pos != 0) {
+		/*
+		 * First position is already being sent, insert into
+		 * second position.
+		 */
+		TAILQ_INSERT_AFTER(&bcs->bcs_bcqueue, bcq, bcqn, bcq_entry);
+	} else {
+		/*
+		 * Old message didn't start being sent, we still have
+		 * time to put this one in the head of the queue.
+		 */
+		TAILQ_INSERT_HEAD(&bcs->bcs_bcqueue, bcqn, bcq_entry);
+		bcb = &bcqn->bcq_bcb;
+		bcs->bcs_bout = bcb;
+	}
+
+	return 0;
+}
+
+static void control_reset_buf(struct bfd_control_buffer *bcb)
+{
+	/* Get ride of old data. */
+	XFREE(MTYPE_BFDD_NOTIFICATION, bcb->bcb_buf);
+	bcb->bcb_pos = 0;
+	bcb->bcb_left = 0;
+}
+
+static void control_read(struct thread *t)
+{
+	struct bfd_control_socket *bcs = THREAD_ARG(t);
+	struct bfd_control_buffer *bcb = &bcs->bcs_bin;
+	int sd = bcs->bcs_sd;
+	struct bfd_control_msg bcm;
+	ssize_t bread;
+	size_t plen;
+
+	/*
+	 * Check if we have already downloaded message content, if so then skip
+	 * to
+	 * download the rest of it and process.
+	 *
+	 * Otherwise download a new message header and allocate the necessary
+	 * memory.
+	 */
+	if (bcb->bcb_buf != NULL)
+		goto skip_header;
+
+	bread = read(sd, &bcm, sizeof(bcm));
+	if (bread == 0) {
+		control_free(bcs);
+		return;
+	}
+	if (bread < 0) {
+		if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
+			goto schedule_next_read;
+
+		zlog_warn("%s: read: %s", __func__, strerror(errno));
+		control_free(bcs);
+		return;
+	}
+
+	/* Validate header fields. */
+	plen = ntohl(bcm.bcm_length);
+	if (plen < 2) {
+		zlog_debug("%s: client closed due small message length: %d",
+			   __func__, bcm.bcm_length);
+		control_free(bcs);
+		return;
+	}
+
+	if (bcm.bcm_ver != BMV_VERSION_1) {
+		zlog_debug("%s: client closed due bad version: %d", __func__,
+			   bcm.bcm_ver);
+		control_free(bcs);
+		return;
+	}
+
+	/* Prepare the buffer to load the message. */
+	bcs->bcs_version = bcm.bcm_ver;
+	bcs->bcs_type = bcm.bcm_type;
+
+	bcb->bcb_pos = sizeof(bcm);
+	bcb->bcb_left = plen;
+	bcb->bcb_buf = XMALLOC(MTYPE_BFDD_NOTIFICATION,
+			       sizeof(bcm) + bcb->bcb_left + 1);
+	if (bcb->bcb_buf == NULL) {
+		zlog_warn("%s: not enough memory for message size: %zu",
+			  __func__, bcb->bcb_left);
+		control_free(bcs);
+		return;
+	}
+
+	memcpy(bcb->bcb_buf, &bcm, sizeof(bcm));
+
+	/* Terminate data string with NULL for later processing. */
+	bcb->bcb_buf[sizeof(bcm) + bcb->bcb_left] = 0;
+
+skip_header:
+	/* Download the remaining data of the message and process it. */
+	bread = read(sd, &bcb->bcb_buf[bcb->bcb_pos], bcb->bcb_left);
+	if (bread == 0) {
+		control_free(bcs);
+		return;
+	}
+	if (bread < 0) {
+		if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
+			goto schedule_next_read;
+
+		zlog_warn("%s: read: %s", __func__, strerror(errno));
+		control_free(bcs);
+		return;
+	}
+
+	bcb->bcb_pos += bread;
+	bcb->bcb_left -= bread;
+	/* We need more data, return to wait more. */
+	if (bcb->bcb_left > 0)
+		goto schedule_next_read;
+
+	switch (bcb->bcb_bcm->bcm_type) {
+	case BMT_REQUEST_ADD:
+		control_handle_request_add(bcs, bcb->bcb_bcm);
+		break;
+	case BMT_REQUEST_DEL:
+		control_handle_request_del(bcs, bcb->bcb_bcm);
+		break;
+	case BMT_NOTIFY:
+		control_handle_notify(bcs, bcb->bcb_bcm);
+		break;
+	case BMT_NOTIFY_ADD:
+		control_handle_notify_add(bcs, bcb->bcb_bcm);
+		break;
+	case BMT_NOTIFY_DEL:
+		control_handle_notify_del(bcs, bcb->bcb_bcm);
+		break;
+
+	default:
+		zlog_debug("%s: unhandled message type: %d", __func__,
+			   bcb->bcb_bcm->bcm_type);
+		control_response(bcs, bcb->bcb_bcm->bcm_id, BCM_RESPONSE_ERROR,
+				 "invalid message type");
+		break;
+	}
+
+	bcs->bcs_version = 0;
+	bcs->bcs_type = 0;
+	control_reset_buf(bcb);
+
+schedule_next_read:
+	bcs->bcs_ev = NULL;
+	thread_add_read(master, control_read, bcs, sd, &bcs->bcs_ev);
+}
+
+static void control_write(struct thread *t)
+{
+	struct bfd_control_socket *bcs = THREAD_ARG(t);
+	struct bfd_control_buffer *bcb = bcs->bcs_bout;
+	int sd = bcs->bcs_sd;
+	ssize_t bwrite;
+
+	bwrite = write(sd, &bcb->bcb_buf[bcb->bcb_pos], bcb->bcb_left);
+	if (bwrite == 0) {
+		control_free(bcs);
+		return;
+	}
+	if (bwrite < 0) {
+		if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {
+			bcs->bcs_outev = NULL;
+			thread_add_write(master, control_write, bcs,
+					 bcs->bcs_sd, &bcs->bcs_outev);
+			return;
+		}
+
+		zlog_warn("%s: write: %s", __func__, strerror(errno));
+		control_free(bcs);
+		return;
+	}
+
+	bcb->bcb_pos += bwrite;
+	bcb->bcb_left -= bwrite;
+	if (bcb->bcb_left > 0) {
+		bcs->bcs_outev = NULL;
+		thread_add_write(master, control_write, bcs, bcs->bcs_sd,
+				 &bcs->bcs_outev);
+		return;
+	}
+
+	control_queue_dequeue(bcs);
+}
+
+
+/*
+ * Message processing
+ */
+static void control_handle_request_add(struct bfd_control_socket *bcs,
+				       struct bfd_control_msg *bcm)
+{
+	const char *json = (const char *)bcm->bcm_data;
+
+	if (config_request_add(json) == 0)
+		control_response(bcs, bcm->bcm_id, BCM_RESPONSE_OK, NULL);
+	else
+		control_response(bcs, bcm->bcm_id, BCM_RESPONSE_ERROR,
+				 "request add failed");
+}
+
+static void control_handle_request_del(struct bfd_control_socket *bcs,
+				       struct bfd_control_msg *bcm)
+{
+	const char *json = (const char *)bcm->bcm_data;
+
+	if (config_request_del(json) == 0)
+		control_response(bcs, bcm->bcm_id, BCM_RESPONSE_OK, NULL);
+	else
+		control_response(bcs, bcm->bcm_id, BCM_RESPONSE_ERROR,
+				 "request del failed");
+}
+
+static struct bfd_session *_notify_find_peer(struct bfd_peer_cfg *bpc)
+{
+	struct peer_label *pl;
+
+	if (bpc->bpc_has_label) {
+		pl = pl_find(bpc->bpc_label);
+		if (pl)
+			return pl->pl_bs;
+	}
+
+	return bs_peer_find(bpc);
+}
+
+static void _control_handle_notify(struct hash_bucket *hb, void *arg)
+{
+	struct bfd_control_socket *bcs = arg;
+	struct bfd_session *bs = hb->data;
+
+	/* Notify peer configuration. */
+	if (bcs->bcs_notify & BCM_NOTIFY_CONFIG)
+		_control_notify_config(bcs, BCM_NOTIFY_CONFIG_ADD, bs);
+
+	/* Notify peer status. */
+	if (bcs->bcs_notify & BCM_NOTIFY_PEER_STATE)
+		_control_notify(bcs, bs);
+}
+
+static void control_handle_notify(struct bfd_control_socket *bcs,
+				  struct bfd_control_msg *bcm)
+{
+	memcpy(&bcs->bcs_notify, bcm->bcm_data, sizeof(bcs->bcs_notify));
+
+	control_response(bcs, bcm->bcm_id, BCM_RESPONSE_OK, NULL);
+
+	/*
+	 * If peer asked for notification configuration, send everything that
+	 * was configured until the moment to sync up.
+	 */
+	if (bcs->bcs_notify & (BCM_NOTIFY_CONFIG | BCM_NOTIFY_PEER_STATE))
+		bfd_id_iterate(_control_handle_notify, bcs);
+}
+
+static int notify_add_cb(struct bfd_peer_cfg *bpc, void *arg)
+{
+	struct bfd_control_socket *bcs = arg;
+	struct bfd_session *bs = _notify_find_peer(bpc);
+
+	if (bs == NULL)
+		return -1;
+
+	control_notifypeer_new(bcs, bs);
+
+	/* Notify peer status. */
+	_control_notify(bcs, bs);
+
+	return 0;
+}
+
+static int notify_del_cb(struct bfd_peer_cfg *bpc, void *arg)
+{
+	struct bfd_control_socket *bcs = arg;
+	struct bfd_session *bs = _notify_find_peer(bpc);
+	struct bfd_notify_peer *bnp;
+
+	if (bs == NULL)
+		return -1;
+
+	bnp = control_notifypeer_find(bcs, bs);
+	if (bnp)
+		control_notifypeer_free(bcs, bnp);
+
+	return 0;
+}
+
+static void control_handle_notify_add(struct bfd_control_socket *bcs,
+				      struct bfd_control_msg *bcm)
+{
+	const char *json = (const char *)bcm->bcm_data;
+
+	if (config_notify_request(bcs, json, notify_add_cb) == 0) {
+		control_response(bcs, bcm->bcm_id, BCM_RESPONSE_OK, NULL);
+		return;
+	}
+
+	control_response(bcs, bcm->bcm_id, BCM_RESPONSE_ERROR,
+			 "failed to parse notify data");
+}
+
+static void control_handle_notify_del(struct bfd_control_socket *bcs,
+				      struct bfd_control_msg *bcm)
+{
+	const char *json = (const char *)bcm->bcm_data;
+
+	if (config_notify_request(bcs, json, notify_del_cb) == 0) {
+		control_response(bcs, bcm->bcm_id, BCM_RESPONSE_OK, NULL);
+		return;
+	}
+
+	control_response(bcs, bcm->bcm_id, BCM_RESPONSE_ERROR,
+			 "failed to parse notify data");
+}
+
+
+/*
+ * Internal functions used by the BFD daemon.
+ */
+static void control_response(struct bfd_control_socket *bcs, uint16_t id,
+			     const char *status, const char *error)
+{
+	struct bfd_control_msg *bcm;
+	char *jsonstr;
+	size_t jsonstrlen;
+
+	/* Generate JSON response. */
+	jsonstr = config_response(status, error);
+	if (jsonstr == NULL) {
+		zlog_warn("%s: config_response: failed to get JSON str",
+			  __func__);
+		return;
+	}
+
+	/* Allocate data and answer. */
+	jsonstrlen = strlen(jsonstr);
+	bcm = XMALLOC(MTYPE_BFDD_NOTIFICATION,
+		      sizeof(struct bfd_control_msg) + jsonstrlen);
+
+	bcm->bcm_length = htonl(jsonstrlen);
+	bcm->bcm_ver = BMV_VERSION_1;
+	bcm->bcm_type = BMT_RESPONSE;
+	bcm->bcm_id = id;
+	memcpy(bcm->bcm_data, jsonstr, jsonstrlen);
+	XFREE(MTYPE_BFDD_NOTIFICATION, jsonstr);
+
+	control_queue_enqueue_first(bcs, bcm);
+}
+
+static void _control_notify(struct bfd_control_socket *bcs,
+			    struct bfd_session *bs)
+{
+	struct bfd_control_msg *bcm;
+	char *jsonstr;
+	size_t jsonstrlen;
+
+	/* Generate JSON response. */
+	jsonstr = config_notify(bs);
+	if (jsonstr == NULL) {
+		zlog_warn("%s: config_notify: failed to get JSON str",
+			  __func__);
+		return;
+	}
+
+	/* Allocate data and answer. */
+	jsonstrlen = strlen(jsonstr);
+	bcm = XMALLOC(MTYPE_BFDD_NOTIFICATION,
+		      sizeof(struct bfd_control_msg) + jsonstrlen);
+
+	bcm->bcm_length = htonl(jsonstrlen);
+	bcm->bcm_ver = BMV_VERSION_1;
+	bcm->bcm_type = BMT_NOTIFY;
+	bcm->bcm_id = htons(BCM_NOTIFY_ID);
+	memcpy(bcm->bcm_data, jsonstr, jsonstrlen);
+	XFREE(MTYPE_BFDD_NOTIFICATION, jsonstr);
+
+	control_queue_enqueue(bcs, bcm);
+}
+
+int control_notify(struct bfd_session *bs, uint8_t notify_state)
+{
+	struct bfd_control_socket *bcs;
+	struct bfd_notify_peer *bnp;
+
+	/* Notify zebra listeners as well. */
+	ptm_bfd_notify(bs, notify_state);
+
+	/*
+	 * PERFORMANCE: reuse the bfd_control_msg allocated data for
+	 * all control sockets to avoid wasting memory.
+	 */
+	TAILQ_FOREACH (bcs, &bglobal.bg_bcslist, bcs_entry) {
+		/*
+		 * Test for all notifications first, then search for
+		 * specific peers.
+		 */
+		if ((bcs->bcs_notify & BCM_NOTIFY_PEER_STATE) == 0) {
+			bnp = control_notifypeer_find(bcs, bs);
+			/*
+			 * If the notification is not configured here,
+			 * don't send it.
+			 */
+			if (bnp == NULL)
+				continue;
+		}
+
+		_control_notify(bcs, bs);
+	}
+
+	return 0;
+}
+
+static void _control_notify_config(struct bfd_control_socket *bcs,
+				   const char *op, struct bfd_session *bs)
+{
+	struct bfd_control_msg *bcm;
+	char *jsonstr;
+	size_t jsonstrlen;
+
+	/* Generate JSON response. */
+	jsonstr = config_notify_config(op, bs);
+	if (jsonstr == NULL) {
+		zlog_warn("%s: config_notify_config: failed to get JSON str",
+			  __func__);
+		return;
+	}
+
+	/* Allocate data and answer. */
+	jsonstrlen = strlen(jsonstr);
+	bcm = XMALLOC(MTYPE_BFDD_NOTIFICATION,
+		      sizeof(struct bfd_control_msg) + jsonstrlen);
+
+	bcm->bcm_length = htonl(jsonstrlen);
+	bcm->bcm_ver = BMV_VERSION_1;
+	bcm->bcm_type = BMT_NOTIFY;
+	bcm->bcm_id = htons(BCM_NOTIFY_ID);
+	memcpy(bcm->bcm_data, jsonstr, jsonstrlen);
+	XFREE(MTYPE_BFDD_NOTIFICATION, jsonstr);
+
+	control_queue_enqueue(bcs, bcm);
+}
+
+int control_notify_config(const char *op, struct bfd_session *bs)
+{
+	struct bfd_control_socket *bcs;
+	struct bfd_notify_peer *bnp;
+
+	/* Remove the control sockets notification for this peer. */
+	if (strcmp(op, BCM_NOTIFY_CONFIG_DELETE) == 0 && bs->refcount > 0) {
+		TAILQ_FOREACH (bcs, &bglobal.bg_bcslist, bcs_entry) {
+			bnp = control_notifypeer_find(bcs, bs);
+			if (bnp)
+				control_notifypeer_free(bcs, bnp);
+		}
+	}
+
+	/*
+	 * PERFORMANCE: reuse the bfd_control_msg allocated data for
+	 * all control sockets to avoid wasting memory.
+	 */
+	TAILQ_FOREACH (bcs, &bglobal.bg_bcslist, bcs_entry) {
+		/*
+		 * Test for all notifications first, then search for
+		 * specific peers.
+		 */
+		if ((bcs->bcs_notify & BCM_NOTIFY_CONFIG) == 0)
+			continue;
+
+		_control_notify_config(bcs, op, bs);
+	}
+
+	return 0;
+}