+static bool ptp_one_step_sync(struct sk_buff *skb)
+{
+ struct ptp_header *hdr;
+ unsigned int ptp_class;
+ u8 msgtype;
+
+ /* No need to parse packet if PTP TS is not involved */
+ if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)))
+ goto not_oss;
+
+ /* Identify and return whether PTP one step sync is being processed */
+ ptp_class = ptp_classify_raw(skb);
+ if (ptp_class == PTP_CLASS_NONE)
+ goto not_oss;
+
+ hdr = ptp_parse_header(skb, ptp_class);
+ if (!hdr)
+ goto not_oss;
+
+ if (hdr->flag_field[0] & PTP_FLAG_TWOSTEP)
+ goto not_oss;
+
+ msgtype = ptp_get_msgtype(hdr, ptp_class);
+ if (msgtype == PTP_MSGTYPE_SYNC)
+ return true;
+
+not_oss:
+ return false;
+}
+