Clean up hardware time stamp support.

Don't say that the "any" device supports any time stamp types; we can't
arrange that every device, including devices that show up in the future,
do hardware time stamping.

If we can ask about hardware time stamp support, don't say we support
hardware time stamping if the answer is "not for all packets".

If we get ERANGE from an attempt to set hardware time stamping, it means
"yes, we support hardware time stamping, but not for all packets
matching that filter"; the filter in question is "all packets", so here
it would mean "we can't do hardware time stamping for all incoming
packets", which means "we can't do time stamping for captured packets".

1 files changed, 54 insertions, 11 deletions

diff --git a/pcap-linux.c b/pcap-linux.c
index 0792f0d5..15f1ad8e 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -4203,12 +4203,20 @@ create_ring(pcap_t *handle, int *status)
 				return -1;
 
 			case EOPNOTSUPP:
+			case ERANGE:
 				/*
 				 * Treat this as a warning, as the
 				 * only way to fix the warning is to
 				 * get an adapter that supports hardware
-				 * time stamps.  We'll just fall back
-				 * on the standard host time stamps.
+				 * time stamps for *all* packets.
+				 * (ERANGE means "we support hardware
+				 * time stamps, but for packets matching
+				 * that particular filter", so it means
+				 * "we don't support hardware time stamps
+				 * for all incoming packets" here.)
+				 *
+				 * We'll just fall back on the standard
+				 * host time stamps.
 				 */
 				*status = PCAP_WARNING_TSTAMP_TYPE_NOTSUP;
 				break;
@@ -5986,8 +5994,11 @@ static const struct {
 };
 #define NUM_SOF_TIMESTAMPING_TYPES	(sizeof sof_ts_type_map / sizeof sof_ts_type_map[0])
 
+/*
+ * Set the list of time stamping types to include all types.
+ */
 static void
-iface_set_default_ts_types(pcap_t *handle)
+iface_set_all_ts_types(pcap_t *handle)
 {
 	int i;
 
@@ -6011,12 +6022,14 @@ iface_ethtool_get_ts_info(pcap_t *handle, char *ebuf)
 	int i, j;
 
 	/*
-	 * This doesn't apply to the "any" device; you have to ask
-	 * specific devices for their capabilities, so just default
-	 * to saying we support all of them.
+	 * This doesn't apply to the "any" device; you can't say "turn on
+	 * hardware time stamping for all devices that exist now and arrange
+	 * that it be turned on for any device that appears in the future",
+	 * and not all devices even necessarily *support* hardware time
+	 * stamping, so don't report any time stamp types.
 	 */
 	if (strcmp(handle->opt.source, "any") == 0) {
-		iface_set_default_ts_types(handle);
+		handle->tstamp_type_list = NULL;
 		return 0;
 	}
 
@@ -6039,10 +6052,11 @@ iface_ethtool_get_ts_info(pcap_t *handle, char *ebuf)
 		close(fd);
 		if (errno == EOPNOTSUPP || errno == EINVAL) {
 			/*
-			 * OK, let's just return all the possible time
-			 * stamping types.
+			 * OK, this OS version or driver doesn't support
+			 * asking for the time stamping types, so let's
+			 * just return all the possible types.
 			 */
-			iface_set_default_ts_types(handle);
+			iface_set_all_ts_types(handle);
 			return 0;
 		}
 		pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
@@ -6052,6 +6066,23 @@ iface_ethtool_get_ts_info(pcap_t *handle, char *ebuf)
 	}
 	close(fd);
 
+	/*
+	 * Do we support hardware time stamping of *all* packets?
+	 */
+	if (!(info.rx_filters & (1 << HWTSTAMP_FILTER_ALL))) {
+		/*
+		 * No, so don't report any time stamp types.
+		 *
+		 * XXX - some devices either don't report
+		 * HWTSTAMP_FILTER_ALL when they do support it, or
+		 * report HWTSTAMP_FILTER_ALL but map it to only
+		 * time stamping a few PTP packets.  See
+		 * http://marc.info/?l=linux-netdev&m=146318183529571&w=2
+		 */
+		handle->tstamp_type_list = NULL;
+		return 0;
+	}
+
 	num_ts_types = 0;
 	for (i = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++) {
 		if (info.so_timestamping & sof_ts_type_map[i].soft_timestamping_val)
@@ -6076,10 +6107,22 @@ static int
 iface_ethtool_get_ts_info(pcap_t *handle, char *ebuf _U_)
 {
 	/*
+	 * This doesn't apply to the "any" device; you can't say "turn on
+	 * hardware time stamping for all devices that exist now and arrange
+	 * that it be turned on for any device that appears in the future",
+	 * and not all devices even necessarily *support* hardware time
+	 * stamping, so don't report any time stamp types.
+	 */
+	if (strcmp(handle->opt.source, "any") == 0) {
+		handle->tstamp_type_list = NULL;
+		return 0;
+	}
+
+	/*
 	 * We don't have an ioctl to use to ask what's supported,
 	 * so say we support everything.
 	 */
-	iface_set_default_ts_types(handle);
+	iface_set_all_ts_types(handle);
 	return 0;
 }
 #endif /* ETHTOOL_GET_TS_INFO */