Introduce a module for slave event monitoring.

This patch adds a new module for slave event monitoring with its own
configuration option, a UDS address.  If the option is enabled, then
the monitor will send events to the configured address.  The default
setting produces an inactive monitor that does nothing.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

config.c

@@ -297,6 +297,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("sanity_freq_limit", 200000000, 0, INT_MAX),
 	GLOB_ITEM_INT("servo_num_offset_values", 10, 0, INT_MAX),
 	GLOB_ITEM_INT("servo_offset_threshold", 0, 0, INT_MAX),
+	GLOB_ITEM_STR("slave_event_monitor", ""),
 	GLOB_ITEM_INT("slaveOnly", 0, 0, 1),
 	GLOB_ITEM_INT("socket_priority", 0, 0, 15),
 	GLOB_ITEM_DBL("step_threshold", 0.0, 0.0, DBL_MAX),

makefile

@@ -29,9 +29,9 @@ TRANSP	= raw.o transport.o udp.o udp6.o uds.o
 TS2PHC	= ts2phc.o lstab.o nmea.o serial.o sock.o ts2phc_generic_master.o \
  ts2phc_master.o ts2phc_phc_master.o ts2phc_nmea_master.o ts2phc_slave.o
 OBJ	= bmc.o clock.o clockadj.o clockcheck.o config.o designated_fsm.o \
- e2e_tc.o fault.o $(FILTERS) fsm.o hash.o interface.o msg.o phc.o port.o \
- port_signaling.o pqueue.o print.o ptp4l.o p2p_tc.o rtnl.o $(SERVOS) sk.o \
- stats.o tc.o $(TRANSP) telecom.o tlv.o tsproc.o unicast_client.o \
+ e2e_tc.o fault.o $(FILTERS) fsm.o hash.o interface.o monitor.o msg.o phc.o \
+ port.o port_signaling.o pqueue.o print.o ptp4l.o p2p_tc.o rtnl.o $(SERVOS) \
+ sk.o stats.o tc.o $(TRANSP) telecom.o tlv.o tsproc.o unicast_client.o \
  unicast_fsm.o unicast_service.o util.o version.o
 
 OBJECTS	= $(OBJ) hwstamp_ctl.o nsm.o phc2sys.o phc_ctl.o pmc.o pmc_common.o \

monitor.c

@@ -0,0 +1,171 @@
+/**
+ * @file monitor.c
+ * @note Copyright (C) 2020 Richard Cochran <richardcochran@gmail.com>
+ * @note SPDX-License-Identifier: GPL-2.0+
+ */
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include "address.h"
+#include "monitor.h"
+#include "print.h"
+
+#define RECORDS_PER_MESSAGE 1
+
+struct monitor_message {
+	struct ptp_message *msg;
+	int records_per_msg;
+	int count;
+};
+
+struct monitor {
+	struct port *dst_port;
+	struct slave_rx_sync_timing_data_tlv *sync_tlv;
+	struct monitor_message sync;
+};
+
+static bool monitor_active(struct monitor *monitor)
+{
+	return monitor->dst_port ? true : false;
+}
+
+static int monitor_forward(struct port *port, struct ptp_message *msg)
+{
+	int err, pdulen = msg->header.messageLength;
+
+	if (msg_pre_send(msg)) {
+		return -1;
+	}
+	err = port_forward_to(port, msg);
+	if (err) {
+		pr_debug("failed to send signaling message to slave event monitor: %s",
+			 strerror(-err));
+	}
+	if (msg_post_recv(msg, pdulen)) {
+		return -1;
+	}
+	msg->header.sequenceId++;
+
+	return 0;
+}
+
+static struct tlv_extra *monitor_init_message(struct monitor_message *mm,
+					      struct port *destination,
+					      uint16_t tlv_type,
+					      size_t tlv_size,
+					      struct address address)
+{
+	struct ptp_message *msg;
+	struct tlv_extra *extra;
+
+	msg = port_signaling_construct(destination, &wildcard_pid);
+	if (!msg) {
+		return NULL;
+	}
+	extra = msg_tlv_append(msg, tlv_size);
+	if (!extra) {
+		msg_put(msg);
+		return NULL;
+	}
+	extra->tlv->type = tlv_type;
+	extra->tlv->length = tlv_size - sizeof(extra->tlv->type) -
+		sizeof(extra->tlv->length);
+
+	mm->msg = msg;
+	mm->msg->address = address;
+	mm->records_per_msg = RECORDS_PER_MESSAGE;
+	mm->count = 0;
+
+	return extra;
+}
+
+static int monitor_init_sync(struct monitor *monitor, struct address address)
+{
+	const size_t tlv_size = sizeof(struct slave_rx_sync_timing_data_tlv) +
+		sizeof(struct slave_rx_sync_timing_record) * RECORDS_PER_MESSAGE;
+	struct tlv_extra *extra;
+
+	extra = monitor_init_message(&monitor->sync, monitor->dst_port,
+				     TLV_SLAVE_RX_SYNC_TIMING_DATA, tlv_size,
+				     address);
+	if (!extra) {
+		return -1;
+	}
+	monitor->sync_tlv = (struct slave_rx_sync_timing_data_tlv *) extra->tlv;
+
+	return 0;
+}
+
+struct monitor *monitor_create(struct config *config, struct port *dst)
+{
+	struct monitor *monitor;
+	struct address address;
+	struct sockaddr_un sa;
+	const char *path;
+
+	monitor = calloc(1, sizeof(*monitor));
+	if (!monitor) {
+		return NULL;
+	}
+	path = config_get_string(config, NULL, "slave_event_monitor");
+	if (!path || !path[0]) {
+		/* Return an inactive monitor. */
+		return monitor;
+	}
+	memset(&sa, 0, sizeof(sa));
+	sa.sun_family = AF_LOCAL;
+	snprintf(sa.sun_path, sizeof(sa.sun_path) - 1, "%s", path);
+	address.sun = sa;
+	address.len = sizeof(sa);
+
+	monitor->dst_port = dst;
+
+	if (monitor_init_sync(monitor, address)) {
+		free(monitor);
+		return NULL;
+	}
+
+	return monitor;
+}
+
+void monitor_destroy(struct monitor *monitor)
+{
+	if (monitor->sync.msg) {
+		msg_put(monitor->sync.msg);
+	}
+	free(monitor);
+}
+
+int monitor_sync(struct monitor *monitor, struct PortIdentity source_pid,
+		 uint16_t seqid, tmv_t t1, tmv_t corr, tmv_t t2)
+{
+	struct slave_rx_sync_timing_record *record;
+	struct ptp_message *msg;
+
+	if (!monitor_active(monitor)) {
+		return 0;
+	}
+
+	msg = monitor->sync.msg;
+
+	if (!pid_eq(&monitor->sync_tlv->sourcePortIdentity, &source_pid)) {
+		/* There was a change in remote master. Drop stale records. */
+		memcpy(&monitor->sync_tlv->sourcePortIdentity, &source_pid,
+		       sizeof(monitor->sync_tlv->sourcePortIdentity));
+		monitor->sync.count = 0;
+	}
+
+	record = monitor->sync_tlv->record + monitor->sync.count;
+	record->sequenceId                 = seqid;
+	record->syncOriginTimestamp        = tmv_to_Timestamp(t1);
+	record->totalCorrectionField       = tmv_to_TimeInterval(corr);
+	record->scaledCumulativeRateOffset = 0;
+	record->syncEventIngressTimestamp  = tmv_to_Timestamp(t2);
+
+	monitor->sync.count++;
+	if (monitor->sync.count == monitor->sync.records_per_msg) {
+		monitor->sync.count = 0;
+		return monitor_forward(monitor->dst_port, msg);
+	}
+	return 0;
+}

monitor.h

@@ -0,0 +1,22 @@
+/**
+ * @file monitor.h
+ * @note Copyright (C) 2020 Richard Cochran <richardcochran@gmail.com>
+ * @note SPDX-License-Identifier: GPL-2.0+
+ */
+#ifndef HAVE_MONITOR_H
+#define HAVE_MONITOR_H
+
+#include "config.h"
+#include "port.h"
+#include "tmv.h"
+
+struct monitor;
+
+struct monitor *monitor_create(struct config *config, struct port *dst);
+
+void monitor_destroy(struct monitor *monitor);
+
+int monitor_sync(struct monitor *monitor, struct PortIdentity source_pid,
+		 uint16_t seqid, tmv_t t1, tmv_t corr, tmv_t t2);
+
+#endif

ptp4l.8

@@ -764,6 +764,12 @@ to the SERVO_LOCKED_STABLE state.  The transition occurs once the last
 'servo_num_offset_values' offsets are all below the threshold value.
 The default value of offset_threshold is 0 (disabled).
 .TP
+.B slave_event_monitor
+Specifies the address of a UNIX domain socket for slave event
+monitoring.  A local client bound to this address will receive
+SLAVE_RX_SYNC_TIMING_DATA and SLAVE_DELAY_TIMING_DATA_NP TLVs.
+The default is the empty string (disabled).
+.TP
 .B write_phase_mode
 This option enables using the "write phase" feature of a PTP Hardware
 Clock.  If supported by the device, this mode uses the hardware's