diff --git a/drivers/net/phy/dp83640.c b/drivers/net/phy/dp83640.c
index c0a617311e2d..ef8b14135133 100644
--- a/drivers/net/phy/dp83640.c
+++ b/drivers/net/phy/dp83640.c
@@ -970,17 +970,6 @@ static void decode_status_frame(struct dp83640_private *dp83640,
 	}
 }
 
-static int is_sync(struct sk_buff *skb, int type)
-{
-	struct ptp_header *hdr;
-
-	hdr = ptp_parse_header(skb, type);
-	if (!hdr)
-		return 0;
-
-	return ptp_get_msgtype(hdr, type) == PTP_MSGTYPE_SYNC;
-}
-
 static void dp83640_free_clocks(void)
 {
 	struct dp83640_clock *clock;
@@ -1396,7 +1385,7 @@ static void dp83640_txtstamp(struct mii_timestamper *mii_ts,
 	switch (dp83640->hwts_tx_en) {
 
 	case HWTSTAMP_TX_ONESTEP_SYNC:
-		if (is_sync(skb, type)) {
+		if (ptp_msg_is_sync(skb, type)) {
 			kfree_skb(skb);
 			return;
 		}
diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 81a76322254c..9e6b29b23935 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -1976,17 +1976,6 @@ static int lan8814_hwtstamp(struct mii_timestamper *mii_ts, struct ifreq *ifr)
 	return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ? -EFAULT : 0;
 }
 
-static bool is_sync(struct sk_buff *skb, int type)
-{
-	struct ptp_header *hdr;
-
-	hdr = ptp_parse_header(skb, type);
-	if (!hdr)
-		return false;
-
-	return ((ptp_get_msgtype(hdr, type) & 0xf) == 0);
-}
-
 static void lan8814_txtstamp(struct mii_timestamper *mii_ts,
 			     struct sk_buff *skb, int type)
 {
@@ -1994,7 +1983,7 @@ static void lan8814_txtstamp(struct mii_timestamper *mii_ts,
 
 	switch (ptp_priv->hwts_tx_type) {
 	case HWTSTAMP_TX_ONESTEP_SYNC:
-		if (is_sync(skb, type)) {
+		if (ptp_msg_is_sync(skb, type)) {
 			kfree_skb(skb);
 			return;
 		}
diff --git a/include/linux/ptp_classify.h b/include/linux/ptp_classify.h
index 9afd34a2d36c..fefa7790dc46 100644
--- a/include/linux/ptp_classify.h
+++ b/include/linux/ptp_classify.h
@@ -126,6 +126,17 @@ static inline u8 ptp_get_msgtype(const struct ptp_header *hdr,
 	return msgtype;
 }
 
+/**
+ * ptp_msg_is_sync - Evaluates whether the given skb is a PTP Sync message
+ * @skb: packet buffer
+ * @type: type of the packet (see ptp_classify_raw())
+ *
+ * This function evaluates whether the given skb is a PTP Sync message.
+ *
+ * Return: true if sync message, false otherwise
+ */
+bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type);
+
 void __init ptp_classifier_init(void);
 #else
 static inline void ptp_classifier_init(void)
@@ -148,5 +159,9 @@ static inline u8 ptp_get_msgtype(const struct ptp_header *hdr,
 	 */
 	return PTP_MSGTYPE_SYNC;
 }
+static inline bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type)
+{
+	return false;
+}
 #endif
 #endif /* _PTP_CLASSIFY_H_ */
diff --git a/net/core/ptp_classifier.c b/net/core/ptp_classifier.c
index dd4cf01d1e0a..598041b0499e 100644
--- a/net/core/ptp_classifier.c
+++ b/net/core/ptp_classifier.c
@@ -137,6 +137,18 @@ struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type)
 }
 EXPORT_SYMBOL_GPL(ptp_parse_header);
 
+bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type)
+{
+	struct ptp_header *hdr;
+
+	hdr = ptp_parse_header(skb, type);
+	if (!hdr)
+		return false;
+
+	return ptp_get_msgtype(hdr, type) == PTP_MSGTYPE_SYNC;
+}
+EXPORT_SYMBOL_GPL(ptp_msg_is_sync);
+
 void __init ptp_classifier_init(void)
 {
 	static struct sock_filter ptp_filter[] __initdata = {