diff --git a/makefile b/makefile
index 5dc5fdc..4fca3f0 100644
--- a/makefile
+++ b/makefile
@@ -27,7 +27,7 @@ OBJ     = bmc.o clock.o clockadj.o clockcheck.o config.o e2e_tc.o fault.o \
  filter.o fsm.o hash.o linreg.o mave.o mmedian.o msg.o ntpshm.o nullf.o phc.o \
  pi.o port.o port_signaling.o print.o ptp4l.o p2p_tc.o raw.o rtnl.o servo.o \
  sk.o stats.o tc.o telecom.o tlv.o transport.o tsproc.o udp.o udp6.o uds.o \
- unicast_fsm.o util.o version.o
+ unicast_client.o unicast_fsm.o util.o version.o
 
 OBJECTS	= $(OBJ) hwstamp_ctl.o nsm.o phc2sys.o phc_ctl.o pmc.o pmc_common.o \
  sysoff.o timemaster.o
diff --git a/unicast_client.c b/unicast_client.c
new file mode 100644
index 0000000..de5eee9
--- /dev/null
+++ b/unicast_client.c
@@ -0,0 +1,512 @@
+/**
+ * @file unicast_client.c
+ * @brief Unicast client implementation
+ * @note Copyright (C) 2018 Richard Cochran <richardcochran@gmail.com>
+ *
+ * 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; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA.
+ */
+#include "port.h"
+#include "port_private.h"
+#include "print.h"
+#include "unicast_client.h"
+
+#define E2E_SYDY_MASK	(1 << ANNOUNCE | 1 << SYNC | 1 << DELAY_RESP)
+#define P2P_SYDY_MASK	(1 << ANNOUNCE | 1 << SYNC)
+
+static struct PortIdentity wildcard = {
+	.clockIdentity = {
+		{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
+	},
+	.portNumber = 0xffff,
+};
+
+static int attach_ack(struct ptp_message *msg, uint8_t message_type_flags)
+{
+	struct ack_cancel_unicast_xmit_tlv *ack;
+	struct tlv_extra *extra;
+
+	extra = msg_tlv_append(msg, sizeof(*ack));
+	if (!extra) {
+		return -1;
+	}
+	ack = (struct ack_cancel_unicast_xmit_tlv *) extra->tlv;
+	ack->type = TLV_ACKNOWLEDGE_CANCEL_UNICAST_TRANSMISSION;
+	ack->length = sizeof(*ack) - sizeof(ack->type) - sizeof(ack->length);
+	ack->message_type_flags = message_type_flags;
+
+	return 0;
+}
+
+static int attach_request(struct ptp_message *msg, int log_period,
+			  uint8_t message_type, int duration)
+{
+	struct request_unicast_xmit_tlv *req;
+	struct tlv_extra *extra;
+
+	extra = msg_tlv_append(msg, sizeof(*req));
+	if (!extra) {
+		return -1;
+	}
+	req = (struct request_unicast_xmit_tlv *) extra->tlv;
+	req->type = TLV_REQUEST_UNICAST_TRANSMISSION;
+	req->length = sizeof(*req) - sizeof(req->type) - sizeof(req->length);
+	req->message_type = message_type << 4;
+	req->logInterMessagePeriod = log_period;
+	req->durationField = duration;
+
+	return 0;
+}
+
+static int unicast_client_announce(struct port *p,
+				   struct unicast_master_address *dst)
+{
+	struct ptp_message *msg;
+	int err;
+
+	msg = port_signaling_construct(p, &dst->address, &dst->portIdentity);
+	if (!msg) {
+		return -1;
+	}
+	err = attach_request(msg, p->logAnnounceInterval, ANNOUNCE,
+			     p->unicast_req_duration);
+	if (err) {
+		goto out;
+	}
+	err = port_prepare_and_send(p, msg, TRANS_GENERAL);
+	if (err) {
+		pr_err("port %hu: signaling message failed", portnum(p));
+	}
+out:
+	msg_put(msg);
+	return err;
+}
+
+static struct unicast_master_address *unicast_client_ok(struct port *p,
+							struct ptp_message *m)
+{
+	struct unicast_master_address *ucma;
+
+	if (!unicast_client_enabled(p)) {
+		return NULL;
+	}
+	if (!pid_eq(&m->signaling.targetPortIdentity, &p->portIdentity) &&
+	    !pid_eq(&m->signaling.targetPortIdentity, &wildcard)) {
+		return NULL;
+	}
+	STAILQ_FOREACH(ucma, &p->unicast_master_table->addrs, list) {
+		if (addreq(transport_type(p->trp), &ucma->address, &m->address)) {
+			break;
+		}
+	}
+	if (!ucma) {
+		pr_warning("port %d: received rogue unicast grant or cancel",
+			   portnum(p));
+		return NULL;
+	}
+	return ucma;
+}
+
+static int unicast_client_peer_renew(struct port *p)
+{
+	struct unicast_master_address *peer;
+	struct ptp_message *msg;
+	struct timespec now;
+	int err;
+
+	if (!p->unicast_master_table->peer_name) {
+		return 0;
+	}
+	err = clock_gettime(CLOCK_MONOTONIC, &now);
+	if (err) {
+		pr_err("clock_gettime failed: %m");
+		return err;
+	}
+	peer = &p->unicast_master_table->peer_addr;
+	if (now.tv_sec < peer->renewal_tmo) {
+		return 0;
+	}
+	peer->renewal_tmo = 0;
+	pr_debug("port %d: time to renew P2P unicast subscription", portnum(p));
+
+	msg = port_signaling_construct(p, &peer->address, &peer->portIdentity);
+	if (!msg) {
+		return -1;
+	}
+	err = attach_request(msg, p->logMinPdelayReqInterval, PDELAY_RESP,
+			     p->unicast_req_duration);
+	if (err) {
+		goto out;
+	}
+	err = port_prepare_and_send(p, msg, TRANS_GENERAL);
+	if (err) {
+		pr_err("port %hu: P2P signaling message failed", portnum(p));
+	}
+out:
+	msg_put(msg);
+	return err;
+}
+
+static int unicast_client_renew(struct port *p,
+				struct unicast_master_address *dst)
+{
+	struct ptp_message *msg;
+	struct timespec now;
+	int err;
+
+	err = clock_gettime(CLOCK_MONOTONIC, &now);
+	if (err) {
+		pr_err("clock_gettime failed: %m");
+		return err;
+	}
+	if (now.tv_sec < dst->renewal_tmo) {
+		return 0;
+	}
+	dst->renewal_tmo = 0;
+	pr_debug("port %d: time to renew unicast subscriptions", portnum(p));
+
+	msg = port_signaling_construct(p, &dst->address, &dst->portIdentity);
+	if (!msg) {
+		return -1;
+	}
+	err = attach_request(msg, p->logAnnounceInterval, ANNOUNCE,
+			     p->unicast_req_duration);
+	if (err) {
+		goto out;
+	}
+
+	if (dst->state == UC_HAVE_SYDY) {
+		err = attach_request(msg, p->logSyncInterval, SYNC,
+				     p->unicast_req_duration);
+		if (err) {
+			goto out;
+		}
+		if (p->delayMechanism != DM_P2P) {
+			err = attach_request(msg, p->logMinDelayReqInterval,
+					     DELAY_RESP,
+					     p->unicast_req_duration);
+			if (err) {
+				goto out;
+			}
+		}
+	}
+
+	err = port_prepare_and_send(p, msg, TRANS_GENERAL);
+	if (err) {
+		pr_err("port %hu: signaling message failed", portnum(p));
+	}
+out:
+	msg_put(msg);
+	return err;
+}
+
+static void unicast_client_set_renewal(struct port *p,
+				       struct unicast_master_address *master,
+				       long duration)
+{
+	struct timespec now;
+	long tmo;
+
+	if (clock_gettime(CLOCK_MONOTONIC, &now)) {
+		pr_err("clock_gettime failed: %m");
+		return;
+	}
+	duration = (3 * duration) / 4;
+	tmo = now.tv_sec + duration;
+	if (!master->renewal_tmo || tmo < master->renewal_tmo) {
+		master->renewal_tmo = tmo;
+		pr_debug("port %d: renewal timeout at %ld", portnum(p), tmo);
+	}
+}
+
+static int unicast_client_sydy(struct port *p,
+			       struct unicast_master_address *dst)
+{
+	struct ptp_message *msg;
+	int err;
+
+	msg = port_signaling_construct(p, &dst->address, &dst->portIdentity);
+	if (!msg) {
+		return -1;
+	}
+	err = attach_request(msg, p->logSyncInterval, SYNC,
+			     p->unicast_req_duration);
+	if (err) {
+		goto out;
+	}
+	if (p->delayMechanism != DM_P2P) {
+		err = attach_request(msg, p->logMinDelayReqInterval, DELAY_RESP,
+				     p->unicast_req_duration);
+		if (err) {
+			goto out;
+		}
+	}
+	err = port_prepare_and_send(p, msg, TRANS_GENERAL);
+	if (err) {
+		pr_err("port %hu: signaling message failed", portnum(p));
+	}
+out:
+	msg_put(msg);
+	return err;
+}
+
+/* public methods */
+
+int unicast_client_cancel(struct port *p, struct ptp_message *m,
+			  struct tlv_extra *extra)
+{
+	struct cancel_unicast_xmit_tlv *cancel;
+	struct unicast_master_address *ucma;
+	struct ptp_message *msg;
+	uint8_t mtype;
+	int err;
+
+	ucma = unicast_client_ok(p, m);
+	if (!ucma) {
+		return 0;
+	}
+	cancel = (struct cancel_unicast_xmit_tlv *) extra->tlv;
+	mtype = cancel->message_type_flags >> 4;
+	switch (mtype) {
+	case ANNOUNCE:
+	case SYNC:
+	case DELAY_RESP:
+		break;
+	default:
+		return 0;
+	}
+	if (cancel->message_type_flags & CANCEL_UNICAST_MAINTAIN_GRANT) {
+		return 0;
+	}
+	pr_warning("port %d: server unilaterally canceled unicast %s grant",
+		   portnum(p), msg_type_string(mtype));
+
+	ucma->state = unicast_fsm(ucma->state, UC_EV_CANCEL);
+	ucma->granted &= ~(1 << mtype);
+
+	/* Respond with ACK. */
+	msg = port_signaling_construct(p, &ucma->address, &ucma->portIdentity);
+	if (!msg) {
+		return -1;
+	}
+	err = attach_ack(msg, cancel->message_type_flags);
+	if (err) {
+		goto out;
+	}
+	err = port_prepare_and_send(p, msg, TRANS_GENERAL);
+	if (err) {
+		pr_err("port %hu: signaling message failed", portnum(p));
+	}
+out:
+	msg_put(msg);
+	return err;
+}
+
+int unicast_client_claim_table(struct port *p)
+{
+	struct unicast_master_address *master, *peer;
+	struct config *cfg = clock_config(p->clock);
+	struct unicast_master_table *table;
+	int table_id;
+
+	table_id = config_get_int(cfg, p->name, "unicast_master_table");
+	if (!table_id) {
+		return 0;
+	}
+	STAILQ_FOREACH(table, &cfg->unicast_master_tables, list) {
+		if (table->table_index == table_id) {
+			break;
+		}
+	}
+	if (!table) {
+		pr_err("port %d: no table with id %d", portnum(p), table_id);
+		return -1;
+	}
+	if (table->port) {
+		pr_err("port %d: table %d already claimed by port %d",
+		       portnum(p), table_id, table->port);
+		return -1;
+	}
+	peer = &table->peer_addr;
+	if (table->peer_name && str2addr(transport_type(p->trp),
+					 table->peer_name, &peer->address)) {
+		pr_err("port %d: bad peer address: %s",
+		       portnum(p), table->peer_name);
+		return -1;
+	}
+	STAILQ_FOREACH(master, &table->addrs, list) {
+		if (master->type != transport_type(p->trp)) {
+			pr_warning("port %d: unicast master transport mismatch",
+				   portnum(p));
+		}
+		if (p->delayMechanism == DM_P2P) {
+			master->sydymsk = P2P_SYDY_MASK;
+		} else {
+			master->sydymsk = E2E_SYDY_MASK;
+		}
+	}
+	table->port = portnum(p);
+	p->unicast_master_table = table;
+	p->unicast_req_duration =
+		config_get_int(cfg, p->name, "unicast_req_duration");
+	return 0;
+}
+
+int unicast_client_enabled(struct port *p)
+{
+	return p->unicast_master_table ? 1 : 0;
+}
+
+void unicast_client_grant(struct port *p, struct ptp_message *m,
+			  struct tlv_extra *extra)
+{
+	struct unicast_master_address *ucma;
+	struct grant_unicast_xmit_tlv *g;
+	int mtype;
+
+	ucma = unicast_client_ok(p, m);
+	if (!ucma) {
+		return;
+	}
+	g = (struct grant_unicast_xmit_tlv *) extra->tlv;
+	mtype = g->message_type >> 4;
+
+	if (!g->durationField) {
+		pr_warning("port %d: unicast grant of %s rejected",
+			   portnum(p), msg_type_string(mtype));
+		if (mtype != PDELAY_RESP) {
+			ucma->state = UC_WAIT;
+		}
+		return;
+	}
+	pr_debug("port %d: unicast %s granted for %u sec",
+		 portnum(p), msg_type_string(mtype), g->durationField);
+
+	if (p->delayMechanism == DM_P2P) {
+		switch (mtype) {
+		case DELAY_RESP:
+			return;
+		case PDELAY_RESP:
+			p->unicast_master_table->peer_addr.portIdentity =
+				m->header.sourcePortIdentity;
+			unicast_client_set_renewal(p,
+				&p->unicast_master_table->peer_addr,
+				g->durationField);
+			p->logMinPdelayReqInterval = g->logInterMessagePeriod;
+			return;
+		default:
+			break;
+		}
+	}
+
+	ucma->granted |= 1 << mtype;
+
+	switch (ucma->state) {
+	case UC_WAIT:
+		if (mtype == ANNOUNCE) {
+			ucma->state = unicast_fsm(ucma->state, UC_EV_GRANT_ANN);
+			ucma->portIdentity = m->header.sourcePortIdentity;
+			unicast_client_set_renewal(p, ucma, g->durationField);
+		}
+		break;
+	case UC_HAVE_ANN:
+		break;
+	case UC_NEED_SYDY:
+		switch (mtype) {
+		case DELAY_RESP:
+			if ((ucma->granted & ucma->sydymsk) == ucma->sydymsk) {
+				ucma->state = unicast_fsm(ucma->state,
+							  UC_EV_GRANT_SYDY);
+			}
+			unicast_client_set_renewal(p, ucma, g->durationField);
+			p->logMinDelayReqInterval = g->logInterMessagePeriod;
+			break;
+		case SYNC:
+			if ((ucma->granted & ucma->sydymsk) == ucma->sydymsk) {
+				ucma->state = unicast_fsm(ucma->state,
+							  UC_EV_GRANT_SYDY);
+			}
+			unicast_client_set_renewal(p, ucma, g->durationField);
+			clock_sync_interval(p->clock, g->logInterMessagePeriod);
+			break;
+		}
+		break;
+	case UC_HAVE_SYDY:
+		switch (mtype) {
+		case ANNOUNCE:
+		case DELAY_RESP:
+		case SYNC:
+			unicast_client_set_renewal(p, ucma, g->durationField);
+			break;
+		}
+		break;
+	}
+}
+
+int unicast_client_set_tmo(struct port *p)
+{
+	return set_tmo_log(p->fda.fd[FD_UNICAST_REQ_TIMER], 1,
+			   p->unicast_master_table->logQueryInterval);
+}
+
+void unicast_client_state_changed(struct port *p)
+{
+	struct unicast_master_address *ucma;
+	struct PortIdentity pid;
+
+	if (!unicast_client_enabled(p)) {
+		return;
+	}
+	pid = clock_parent_identity(p->clock);
+
+	STAILQ_FOREACH(ucma, &p->unicast_master_table->addrs, list) {
+		if (pid_eq(&ucma->portIdentity, &pid)) {
+			ucma->state = unicast_fsm(ucma->state, UC_EV_SELECTED);
+		} else {
+			ucma->state = unicast_fsm(ucma->state, UC_EV_UNSELECTED);
+		}
+	}
+}
+
+int unicast_client_timer(struct port *p)
+{
+	struct unicast_master_address *master;
+	int err = 0;
+
+	STAILQ_FOREACH(master, &p->unicast_master_table->addrs, list) {
+		if (master->type != transport_type(p->trp)) {
+			continue;
+		}
+		switch (master->state) {
+		case UC_WAIT:
+			err = unicast_client_announce(p, master);
+			break;
+		case UC_HAVE_ANN:
+			err = unicast_client_renew(p, master);
+			break;
+		case UC_NEED_SYDY:
+			err = unicast_client_sydy(p, master);
+			break;
+		case UC_HAVE_SYDY:
+			err = unicast_client_renew(p, master);
+			break;
+		}
+		if (p->delayMechanism == DM_P2P) {
+			unicast_client_peer_renew(p);
+		}
+	}
+
+	unicast_client_set_tmo(p);
+	return err;
+}
diff --git a/unicast_client.h b/unicast_client.h
new file mode 100644
index 0000000..fc8dc6f
--- /dev/null
+++ b/unicast_client.h
@@ -0,0 +1,79 @@
+/**
+ * @file unicast_client.h
+ * @brief Unicast client implementation
+ * @note Copyright (C) 2018 Richard Cochran <richardcochran@gmail.com>
+ *
+ * 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; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA.
+ */
+#ifndef HAVE_UNICAST_CLIENT_H
+#define HAVE_UNICAST_CLIENT_H
+
+/**
+ * Handles a CANCEL_UNICAST_TRANSMISSION TLV from the grantor.
+ * @param p      The port on which the signaling message was received.
+ * @param m      The signaling message containing the cancellation.
+ * @param extra  The TLV containing the cancellation.
+ * @return       Zero on success, or non-zero
+ *               if transmission of the ACK message failed.
+ */
+int unicast_client_cancel(struct port *p, struct ptp_message *m,
+			  struct tlv_extra *extra);
+
+/**
+ * Finds and initializes the unicast master table configured for this
+ * port, if any.
+ * @param port   The port in question.
+ * @return       Zero on success, non-zero otherwise.
+ */
+int unicast_client_claim_table(struct port *port);
+
+/**
+ * Tests whether a unicast master table is associated with a given port.
+ * @param p      The port in question.
+ * @return       One (1) if a unicast master table is configured on the port,
+ *               or zero otherwise.
+ */
+int unicast_client_enabled(struct port *p);
+
+/**
+ * Handles a GRANT_UNICAST_TRANSMISSION TLV from the grantor.
+ * @param p      The port on which the signaling message was received.
+ * @param m      The signaling message containing the grant.
+ * @param extra  The TLV containing the grant.
+ */
+void unicast_client_grant(struct port *p, struct ptp_message *m,
+			  struct tlv_extra *extra);
+
+/**
+ * Programs the unicast request timer.
+ * @param p      The port in question.
+ * @return       Zero on success, non-zero otherwise.
+ */
+int unicast_client_set_tmo(struct port *p);
+
+/**
+ * Notifies the unicast client code that the port state has changed.
+ * @param p      The port in question.
+ */
+void unicast_client_state_changed(struct port *p);
+
+/**
+ * Handles the unicast request timer, sending requests as needed.
+ * @param p      The port in question.
+ * @return       Zero on success, non-zero otherwise.
+ */
+int unicast_client_timer(struct port *p);
+
+#endif