config: Add min_neighbor_prop_delay configuration variable

When peer delay is < min_neighbor_prop_delay the port is flagged
as non 802.1AS capable. min_neighbor_prop_delay defaults to -20ms.

Signed-off-by: Delio Brignoli <dbrignoli@audioscience.com>

config.c

@@ -125,6 +125,12 @@ static enum parser_result parse_pod_setting(const char *option,
 			return r;
 		pod->neighborPropDelayThresh = uval;
 
+	} else if (!strcmp(option, "min_neighbor_prop_delay")) {
+		r = get_ranged_int(value, &val, INT_MIN, -1);
+		if (r != PARSED_OK)
+			return r;
+		pod->min_neighbor_prop_delay = val;
+
 	} else if (!strcmp(option, "fault_badpeernet_interval")) {
 		pod->flt_interval_pertype[FT_BAD_PEER_NETWORK].type = FTMO_LINEAR_SECONDS;
 		if (!strcasecmp("ASAP", value)) {

ds.h

@@ -136,6 +136,7 @@ struct port_defaults {
 	int freq_est_interval; /*log seconds*/
 	struct fault_interval flt_interval_pertype[FT_CNT];
 	UInteger32 neighborPropDelayThresh; /*nanoseconds*/
+	int min_neighbor_prop_delay; /*nanoseconds*/
 };
 
 #endif

gPTP.cfg

@@ -23,6 +23,7 @@ syncReceiptTimeout	3
 delayAsymmetry		0
 fault_reset_interval	4
 neighborPropDelayThresh	800
+min_neighbor_prop_delay	-20000000
 #
 # Run time options
 #

port.c

@@ -101,6 +101,7 @@ struct port {
 	Enumeration8        delayMechanism;
 	Integer8            logMinPdelayReqInterval;
 	UInteger32          neighborPropDelayThresh;
+	int                 min_neighbor_prop_delay;
 	enum fault_type     last_fault_type;
 	unsigned int        versionNumber; /*UInteger4*/
 	/* foreignMasterDS */
@@ -475,6 +476,15 @@ static int port_capable(struct port *p)
 		goto not_capable;
 	}
 
+	if (tmv_to_nanoseconds(p->peer_delay) <	p->min_neighbor_prop_delay) {
+		if (p->asCapable)
+			pr_debug("port %hu: peer_delay (%" PRId64 ") < min_neighbor_prop_delay "
+				"(%" PRId32 "), resetting asCapable", portnum(p),
+				tmv_to_nanoseconds(p->peer_delay),
+				p->min_neighbor_prop_delay);
+		goto not_capable;
+	}
+
 	if (p->pdr_missing > ALLOWED_LOST_RESPONSES) {
 		if (p->asCapable)
 			pr_debug("port %hu: missed %d peer delay resp, "
@@ -1378,6 +1388,7 @@ static int port_initialize(struct port *p)
 	p->logSyncInterval         = p->pod.logSyncInterval;
 	p->logMinPdelayReqInterval = p->pod.logMinPdelayReqInterval;
 	p->neighborPropDelayThresh = p->pod.neighborPropDelayThresh;
+	p->min_neighbor_prop_delay = p->pod.min_neighbor_prop_delay;
 
 	for (i = 0; i < N_TIMER_FDS; i++) {
 		fd[i] = -1;

ptp4l.8

@@ -193,6 +193,10 @@ The default is UDPv4.
 Upper limit for peer delay in nanoseconds. If the estimated peer delay is
 greater than this value the port is marked as not 802.1AS capable.
 .TP
+.B min_neighbor_prop_delay
+Lower limit for peer delay in nanoseconds. If the estimated peer delay is
+smaller than this value the port is marked as not 802.1AS capable.
+.TP
 .B delay_filter
 Select the algorithm used to filter the measured delay and peer delay. Possible
 values are moving_average and moving_median.

ptp4l.c

@@ -17,6 +17,7 @@
  * with this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
+#include <limits.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -90,6 +91,7 @@ static struct config cfg_settings = {
 		.freq_est_interval = 1,
 		/* Default to very a large neighborPropDelay threshold */
 		.neighborPropDelayThresh = 20000000,
+		.min_neighbor_prop_delay = -20000000,
 	},
 
 	.timestamping = TS_HARDWARE,