Add support for binding sockets to virtual clocks.

With the latest kernels it is possible to create virtual PHCs on top of
a free-running physical PHC. In order for the application to get
timestamps captured by the clock which it is controlling, it needs to
bind its sockets to the clock using a new field in the SO_TIMESTAMPING
option.

Extend the interface structure with the vclock index and modify the
transport code to pass it to sk_timestamping_init() to bind the sockets
to the clock.

Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>

interface.c

@@ -12,6 +12,7 @@ struct interface {
 	char name[MAX_IFNAME_SIZE + 1];
 	char ts_label[MAX_IFNAME_SIZE + 1];
 	struct sk_ts_info ts_info;
+	int vclock;
 };
 
 struct interface *interface_create(const char *name)
@@ -23,6 +24,7 @@ struct interface *interface_create(const char *name)
 		return NULL;
 	}
 	strncpy(iface->name, name, MAX_IFNAME_SIZE);
+	iface->vclock = -1;
 
 	return iface;
 }
@@ -76,3 +78,13 @@ bool interface_tsmodes_supported(struct interface *iface, int modes)
 	}
 	return false;
 }
+
+void interface_set_vclock(struct interface *iface, int vclock)
+{
+	iface->vclock = vclock;
+}
+
+int interface_get_vclock(struct interface *iface)
+{
+	return iface->vclock;
+}

interface.h

@@ -91,4 +91,18 @@ bool interface_tsinfo_valid(struct interface *iface);
  */
 bool interface_tsmodes_supported(struct interface *iface, int modes);
 
+/**
+ * Set the vclock (virtual PHC) to be used for timestamping on an interface.
+ * @param iface  The interface of interest.
+ * @param vclock The index of the vclock.
+ */
+void interface_set_vclock(struct interface *iface, int vclock);
+
+/**
+ * Get the vclock index set for the interface.
+ * @param iface  The interface of interest.
+ * @return       The index of the vclock, or -1 if not set.
+ */
+int interface_get_vclock(struct interface *iface);
+
 #endif

missing.h

@@ -62,6 +62,17 @@ enum {
 };
 #endif
 
+#ifndef HAVE_VCLOCKS
+enum {
+	SOF_TIMESTAMPING_BIND_PHC = (1 << 15),
+};
+
+struct so_timestamping {
+	int flags;
+	int bind_phc;
+};
+#endif
+
 #ifdef PTP_EXTTS_REQUEST2
 #define PTP_EXTTS_REQUEST_FAILED "PTP_EXTTS_REQUEST2 failed: %m"
 #else

raw.c

@@ -243,7 +243,8 @@ static int raw_open(struct transport *t, struct interface *iface,
 	if (gfd < 0)
 		goto no_general;
 
-	if (sk_timestamping_init(efd, name, ts_type, TRANS_IEEE_802_3))
+	if (sk_timestamping_init(efd, name, ts_type, TRANS_IEEE_802_3,
+				 interface_get_vclock(iface)))
 		goto no_timestamping;
 
 	if (sk_general_init(gfd))

sk.c

@@ -447,9 +447,10 @@ int sk_set_priority(int fd, int family, uint8_t dscp)
 }
 
 int sk_timestamping_init(int fd, const char *device, enum timestamp_type type,
-			 enum transport_type transport)
+			 enum transport_type transport, int vclock)
 {
 	int err, filter1, filter2 = 0, flags, tx_type = HWTSTAMP_TX_ON;
+	struct so_timestamping timestamping;
 
 	switch (type) {
 	case TS_SOFTWARE:
@@ -509,8 +510,14 @@ int sk_timestamping_init(int fd, const char *device, enum timestamp_type type,
 			return err;
 	}
 
+	if (vclock >= 0)
+		flags |= SOF_TIMESTAMPING_BIND_PHC;
+
+	timestamping.flags = flags;
+	timestamping.bind_phc = vclock;
+
 	if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING,
-		       &flags, sizeof(flags)) < 0) {
+		       &timestamping, sizeof(timestamping)) < 0) {
 		pr_err("ioctl SO_TIMESTAMPING failed: %m");
 		return -1;
 	}

sk.h

@@ -124,10 +124,11 @@ int sk_set_priority(int fd, int family, uint8_t dscp);
  * @param device      The name of the network interface to configure.
  * @param type        The requested flavor of time stamping.
  * @param transport   The type of transport used.
+ * @param vclock      Index of the virtual PHC, or -1 for the physical clock.
  * @return            Zero on success, non-zero otherwise.
  */
 int sk_timestamping_init(int fd, const char *device, enum timestamp_type type,
-			 enum transport_type transport);
+			 enum transport_type transport, int vclock);
 
 /**
  * Limits the time that RECVMSG(2) will poll while waiting for the tx timestamp

udp.c

@@ -179,7 +179,8 @@ static int udp_open(struct transport *t, struct interface *iface,
 	if (gfd < 0)
 		goto no_general;
 
-	if (sk_timestamping_init(efd, interface_label(iface), ts_type, TRANS_UDP_IPV4))
+	if (sk_timestamping_init(efd, interface_label(iface), ts_type, TRANS_UDP_IPV4,
+				 interface_get_vclock(iface)))
 		goto no_timestamping;
 
 	if (sk_general_init(gfd))

udp6.c

@@ -196,7 +196,8 @@ static int udp6_open(struct transport *t, struct interface *iface,
 	if (gfd < 0)
 		goto no_general;
 
-	if (sk_timestamping_init(efd, interface_label(iface), ts_type, TRANS_UDP_IPV6))
+	if (sk_timestamping_init(efd, interface_label(iface), ts_type,
+				 TRANS_UDP_IPV6, interface_get_vclock(iface)))
 		goto no_timestamping;
 
 	if (sk_general_init(gfd))