diff --git a/e2e_tc.c b/e2e_tc.c
index 5a5c092..03b1a4f 100644
--- a/e2e_tc.c
+++ b/e2e_tc.c
@@ -147,7 +147,7 @@ enum fsm_event e2e_event(struct port *p, int fd_index)
 	if (msg_sots_valid(msg)) {
 		ts_add(&msg->hwts.ts, -p->rx_timestamp_offset);
 	}
-	if (msg->header.flagField[0] & UNICAST) {
+	if (msg_unicast(msg)) {
 		pl_warning(600, "cannot handle unicast messages!");
 		msg_put(msg);
 		return EV_NONE;
diff --git a/msg.h b/msg.h
index 38d16ef..58a916c 100644
--- a/msg.h
+++ b/msg.h
@@ -394,6 +394,16 @@ static inline int msg_sots_valid(struct ptp_message *m)
 	return !tmv_is_zero(m->hwts.ts);
 }
 
+/**
+ * Test whether a message is a unicast message.
+ * @param m  Message to test.
+ * @return   One if the message is unicast, zero otherwise.
+ */
+static inline Boolean msg_unicast(struct ptp_message *m)
+{
+	return field_is_set(m, 0, UNICAST);
+}
+
 /**
  * Work around buggy 802.1AS switches.
  */
diff --git a/nsm.c b/nsm.c
index 461ef7d..1a6475f 100644
--- a/nsm.c
+++ b/nsm.c
@@ -138,7 +138,7 @@ static void nsm_handle_msg(struct nsm *nsm, struct ptp_message *msg, FILE *fp)
 	    ntohs(nsm->nsm_delay_req->header.sequenceId)) {
 		return;
 	}
-	if (!(msg->header.flagField[0] & UNICAST)) {
+	if (!msg_unicast(msg)) {
 		return;
 	}
 
diff --git a/p2p_tc.c b/p2p_tc.c
index b2a444e..22ec9a7 100644
--- a/p2p_tc.c
+++ b/p2p_tc.c
@@ -150,7 +150,7 @@ enum fsm_event p2p_event(struct port *p, int fd_index)
 	if (msg_sots_valid(msg)) {
 		ts_add(&msg->hwts.ts, -p->rx_timestamp_offset);
 	}
-	if (msg->header.flagField[0] & UNICAST) {
+	if (msg_unicast(msg)) {
 		pl_warning(600, "cannot switch unicast messages!");
 		msg_put(msg);
 		return EV_NONE;
diff --git a/port.c b/port.c
index 957a3b4..a777701 100644
--- a/port.c
+++ b/port.c
@@ -697,7 +697,7 @@ static int port_nsm_reply(struct port *p, struct ptp_message *m)
 	if (!p->hybrid_e2e) {
 		return 0;
 	}
-	if (!(m->header.flagField[0] & UNICAST)) {
+	if (!msg_unicast(m)) {
 		return 0;
 	}
 	TAILQ_FOREACH(extra, &m->tlv_list, list) {
@@ -1753,7 +1753,7 @@ static int process_delay_req(struct port *p, struct ptp_message *m)
 
 	msg->delay_resp.requestingPortIdentity = m->header.sourcePortIdentity;
 
-	if (p->hybrid_e2e && m->header.flagField[0] & UNICAST) {
+	if (p->hybrid_e2e && msg_unicast(m)) {
 		msg->address = m->address;
 		msg->header.flagField[0] |= UNICAST;
 		msg->header.logMessageInterval = 0x7f;
@@ -1819,7 +1819,7 @@ void process_delay_resp(struct port *p, struct ptp_message *m)
 	if (p->logMinDelayReqInterval == rsp->hdr.logMessageInterval) {
 		return;
 	}
-	if (m->header.flagField[0] & UNICAST) {
+	if (msg_unicast(m)) {
 		/* Unicast responses have logMinDelayReqInterval set to 0x7F. */
 		return;
 	}
@@ -2563,7 +2563,7 @@ int port_prepare_and_send(struct port *p, struct ptp_message *msg,
 	if (msg_pre_send(msg)) {
 		return -1;
 	}
-	if (msg->header.flagField[0] & UNICAST) {
+	if (msg_unicast(msg)) {
 		cnt = transport_sendto(p->trp, &p->fda, event, msg);
 	} else {
 		cnt = transport_send(p->trp, &p->fda, event, msg);