Add possibility to set clockIdentity

Currently the clockIdentity is generated from the mac address of the first
interface/port in config file. This patch add the possibility to set it in
config file.
The reason is if the stack is restarted with a different set of ports, it
may be circumstances when clockIdentity needs to be equal as before
restart even if the port setup is different.

Signed-off-by: Anders Selhammer <anders.selhammer@est.tech>

clock.c

@@ -988,9 +988,19 @@ struct clock *clock_create(enum clock_type type, struct config *config,
 		pr_info("selected /dev/ptp%d as PTP clock", phc_index);
 	}
 
-	if (generate_clock_identity(&c->dds.clockIdentity, iface->name)) {
+	if (strcmp(config_get_string(config, NULL, "clockIdentity"),
-		pr_err("failed to generate a clock identity");
+		   "000000.0000.000000") == 0) {
-		return NULL;
+		if (generate_clock_identity(&c->dds.clockIdentity,
+					    iface->name)) {
+			pr_err("failed to generate a clock identity");
+			return NULL;
+		}
+	} else {
+		if (str2cid(config_get_string(config, NULL, "clockIdentity"),
+					      &c->dds.clockIdentity)) {
+			pr_err("failed to set clock identity");
+			return NULL;
+		}
 	}
 
 	/* Configure the UDS. */

config.c

@@ -202,6 +202,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("check_fup_sync", 0, 0, 1),
 	GLOB_ITEM_INT("clockAccuracy", 0xfe, 0, UINT8_MAX),
 	GLOB_ITEM_INT("clockClass", 248, 0, UINT8_MAX),
+	GLOB_ITEM_STR("clockIdentity", "000000.0000.000000"),
 	GLOB_ITEM_ENU("clock_servo", CLOCK_SERVO_PI, clock_servo_enu),
 	GLOB_ITEM_ENU("clock_type", CLOCK_TYPE_ORDINARY, clock_type_enu),
 	GLOB_ITEM_ENU("dataset_comparison", DS_CMP_IEEE1588, dataset_comp_enu),

ptp4l.8

@@ -395,6 +395,15 @@ The clockAccuracy attribute of the local clock. It is used in the best master
 selection algorithm.
 The default is 0xFE.
 .TP
+.B clockIdentity
+The clockIdentity attribute of the local clock.
+The clockIdentity is an 8-octet array and should in this configuration be
+written in textual form, see default. It should be unique since it is used to
+identify the specific clock.
+If default is used or if not set at all, the clockIdentity will be automtically
+generated.
+The default is "000000.0000.000000"
+.TP
 .B offsetScaledLogVariance
 The offsetScaledLogVariance attribute of the local clock. It characterizes the
 stability of the clock.

util.c

@@ -218,6 +218,21 @@ int str2mac(const char *s, unsigned char mac[MAC_LEN])
 	return 0;
 }
 
+int str2cid(const char *s, struct ClockIdentity *result)
+{
+	struct ClockIdentity cid;
+	unsigned char *ptr = cid.id;
+	int c;
+	c = sscanf(s, " %02hhx%02hhx%02hhx.%02hhx%02hhx.%02hhx%02hhx%02hhx",
+		   &ptr[0], &ptr[1], &ptr[2], &ptr[3],
+		   &ptr[4], &ptr[5], &ptr[6], &ptr[7]);
+	if (c == 8) {
+		*result = cid;
+		return 0;
+	}
+	return -1;
+}
+
 int str2pid(const char *s, struct PortIdentity *result)
 {
 	struct PortIdentity pid;

util.h

@@ -133,6 +133,15 @@ int str2addr(enum transport_type type, const char *s, struct address *addr);
  */
 int str2mac(const char *s, unsigned char mac[MAC_LEN]);
 
+/**
+ * Scan a string containing a clock identity and convert it into binary form.
+ *
+ * @param s       String in human readable form.
+ * @param result  Pointer to a buffer to hold the result.
+ * @return Zero on success, or -1 if the string is incorrectly formatted.
+ */
+int str2cid(const char *s, struct ClockIdentity *result);
+
 /**
  * Scan a string containing a port identity and convert it into binary form.
  *