net: define receive timestamp filter for NTP

Add HWTSTAMP_FILTER_NTP_ALL to the hwtstamp_rx_filters enum for
timestamping of NTP packets. There is currently only one driver
(phyter) that could support it directly.

CC: Richard Cochran <richardcochran@gmail.com>
CC: Willem de Bruijn <willemb@google.com>
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/net_tstamp.h

@@ -125,6 +125,9 @@ enum hwtstamp_rx_filters {
 	HWTSTAMP_FILTER_PTP_V2_SYNC,
 	/* PTP v2/802.AS1, any layer, Delay_req packet */
 	HWTSTAMP_FILTER_PTP_V2_DELAY_REQ,
+
+	/* NTP, UDP, all versions and packet modes */
+	HWTSTAMP_FILTER_NTP_ALL,
 };
 
 #endif /* _NET_TIMESTAMPING_H */

net/core/dev_ioctl.c

@@ -227,6 +227,8 @@ static int net_hwtstamp_validate(struct ifreq *ifr)
 	case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
 		rx_filter_valid = 1;
 		break;
+	case HWTSTAMP_FILTER_NTP_ALL:
+		break;
 	}
 
 	if (!tx_type_valid || !rx_filter_valid)