check/: Add a most minimal test for the net client clock. More to come later.

Original commit message from CVS:
2005-11-17  Andy Wingo  <wingo@pobox.com>

* check/Makefile.am (check_PROGRAMS):
* check/net/gstnetclientclock.c: Add a most minimal test for the
net client clock. More to come later.

* gst/net/gstnet.h:
* gst/net/Makefile.am: Add netclientclock.

* gst/net/gstnetclientclock.h:
* gst/net/gstnetclientclock.c: New files, implement an untested
GstClock that takes its time from a network time provider.
Implements the algorithm in network-clock.scm.

* tests/network-clock.scm (*window-size*): Rename from
*queue-length*.
* tests/network-clock.scm (network-time):
* tests/network-clock-utils.scm (q-push): Update callers.

ChangeLog

@@ -1,3 +1,22 @@
+2005-11-17  Andy Wingo  <wingo@pobox.com>
+
+	* check/Makefile.am (check_PROGRAMS): 
+	* check/net/gstnetclientclock.c: Add a most minimal test for the
+	net client clock. More to come later.
+
+	* gst/net/gstnet.h: 
+	* gst/net/Makefile.am: Add netclientclock.
+
+	* gst/net/gstnetclientclock.h:
+	* gst/net/gstnetclientclock.c: New files, implement an untested
+	GstClock that takes its time from a network time provider.
+	Implements the algorithm in network-clock.scm.
+
+	* tests/network-clock.scm (*window-size*): Rename from
+	*queue-length*.
+	* tests/network-clock.scm (network-time): 
+	* tests/network-clock-utils.scm (q-push): Update callers.
+
 2005-11-17  Wim Taymans  <wim@fluendo.com>
 
 	* gst/gstbin.c: (gst_bin_provide_clock_func),

check/Makefile.am

@@ -57,6 +57,7 @@ check_PROGRAMS =				\
 	states/sinks				\
 	gst-libs/controller			\
 	gst-libs/gdp				\
+	net/gstnetclientclock			\
 	net/gstnettimeprovider
 
 TESTS = $(check_PROGRAMS)
@@ -79,6 +80,9 @@ gst_libs_controller_LDADD = \
 	$(top_builddir)/libs/gst/controller/libgstcontroller-@GST_MAJORMINOR@.la \
 	$(LDADD)
 
+net_gstnetclientclock_LDADD = \
+	$(top_builddir)/gst/net/libgstnet-tempname-@GST_MAJORMINOR@.la \
+	$(LDADD)
 net_gstnettimeprovider_LDADD = \
 	$(top_builddir)/gst/net/libgstnet-tempname-@GST_MAJORMINOR@.la \
 	$(LDADD)

check/net/gstnetclientclock.c

@@ -0,0 +1,137 @@
+/* GStreamer
+ * Copyright (C) 2005 Andy Wingo <wingo@pobox.com>
+ *
+ * gstnetclientclock.c: Unit test for the network client clock
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <gst/check/gstcheck.h>
+#include <gst/net/gstnet.h>
+
+#include <unistd.h>
+
+GST_START_TEST (test_instantiation)
+{
+  GstClock *client, *local;
+
+  local = gst_system_clock_obtain ();
+  client = gst_net_client_clock_new (NULL, "127.0.0.1", 1234, GST_SECOND);
+  fail_unless (local != NULL, "failed to get system clock");
+  fail_unless (client != NULL, "failed to get network client clock");
+
+  /* one for gstreamer, one for us */
+  ASSERT_OBJECT_REFCOUNT (local, "system clock", 2);
+  ASSERT_OBJECT_REFCOUNT (client, "network client clock", 1);
+
+  gst_object_unref (client);
+
+  ASSERT_OBJECT_REFCOUNT (local, "net time provider", 2);
+
+  gst_object_unref (local);
+}
+
+GST_END_TEST;
+
+#if 0
+GST_START_TEST (test_functioning)
+{
+  GstNetTimeProvider *ntp;
+  GstNetTimePacket *packet;
+  GstClock *clock;
+  GstClockTime local;
+  struct sockaddr_in servaddr;
+  gint port = -1, sockfd, ret;
+  socklen_t len;
+
+  clock = gst_system_clock_obtain ();
+  fail_unless (clock != NULL, "failed to get system clock");
+  ntp = gst_net_time_provider_new (clock, "127.0.0.1", -1);
+  fail_unless (ntp != NULL, "failed to create net time provider");
+
+  g_object_get (ntp, "port", &port, NULL);
+  fail_unless (port > 0);
+
+  sockfd = socket (AF_INET, SOCK_DGRAM, 0);
+  fail_if (sockfd < 0, "socket failed");
+
+  memset (&servaddr, 0, sizeof (servaddr));
+  servaddr.sin_family = AF_INET;
+  servaddr.sin_port = htons (port);
+  inet_aton ("127.0.0.1", &servaddr.sin_addr);
+
+  packet = gst_net_time_packet_new (NULL);
+  fail_unless (packet != NULL, "failed to create packet");
+
+  packet->local_time = local = gst_clock_get_time (clock);
+
+  len = sizeof (servaddr);
+  ret = gst_net_time_packet_send (packet, sockfd,
+      (struct sockaddr *) &servaddr, len);
+
+  fail_unless (ret == GST_NET_TIME_PACKET_SIZE, "failed to send packet");
+
+  g_free (packet);
+
+  packet = gst_net_time_packet_receive (sockfd, (struct sockaddr *) &servaddr,
+      &len);
+
+  fail_unless (packet != NULL, "failed to receive packet");
+  fail_unless (packet->local_time == local, "local time is not the same");
+  fail_unless (packet->remote_time > local, "remote time not after local time");
+  fail_unless (packet->remote_time < gst_clock_get_time (clock),
+      "remote time in the future");
+
+  g_free (packet);
+
+  close (sockfd);
+
+  gst_object_unref (ntp);
+  gst_object_unref (clock);
+}
+
+GST_END_TEST;
+#endif
+
+Suite *
+gst_net_client_clock_suite (void)
+{
+  Suite *s = suite_create ("GstNetClientClock");
+  TCase *tc_chain = tcase_create ("generic tests");
+
+  suite_add_tcase (s, tc_chain);
+  tcase_add_test (tc_chain, test_instantiation);
+  /* tcase_add_test (tc_chain, test_functioning); */
+
+  return s;
+}
+
+int
+main (int argc, char **argv)
+{
+  int nf;
+
+  Suite *s = gst_net_client_clock_suite ();
+  SRunner *sr = srunner_create (s);
+
+  gst_check_init (&argc, &argv);
+
+  srunner_run_all (sr, CK_NORMAL);
+  nf = srunner_ntests_failed (sr);
+  srunner_free (sr);
+
+  return nf;
+}

check/net/gstnettimeprovider.c

@@ -74,7 +74,7 @@ GST_START_TEST (test_functioning)
 
   memset (&servaddr, 0, sizeof (servaddr));
   servaddr.sin_family = AF_INET;
-  servaddr.sin_port = port;
+  servaddr.sin_port = htons (port);
   inet_aton ("127.0.0.1", &servaddr.sin_addr);
 
   packet = gst_net_time_packet_new (NULL);

gst/net/Makefile.am

@@ -5,10 +5,12 @@ lib_LTLIBRARIES = libgstnet-tempname-@GST_MAJORMINOR@.la
 libgstnet_tempname_@GST_MAJORMINOR@_includedir = $(includedir)/gstreamer-@GST_MAJORMINOR@/gst/net
 libgstnet_tempname_@GST_MAJORMINOR@_include_HEADERS = \
     gstnet.h \
+    gstnetclientclock.h \
     gstnettimepacket.h \
     gstnettimeprovider.h
 
 libgstnet_tempname_@GST_MAJORMINOR@_la_SOURCES = \
+    gstnetclientclock.c \
     gstnettimepacket.c \
     gstnettimeprovider.c
 

gst/net/gstnet.h

@@ -22,6 +22,7 @@
 #define __GST_NET_H__
 
 
+#include <gst/net/gstnetclientclock.h>
 #include <gst/net/gstnettimepacket.h>
 #include <gst/net/gstnettimeprovider.h>
 

gst/net/gstnetclientclock.c

@@ -0,0 +1,592 @@
+/* GStreamer
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2005 Wim Taymans <wim@fluendo.com>
+ *                    2005 Andy Wingo <wingo@pobox.com>
+ *
+ * gstnetclientclock.h: clock that synchronizes itself to a time provider over
+ * the network
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <unistd.h>
+
+#include "gstnettimepacket.h"
+#include "gstnetclientclock.h"
+
+GST_DEBUG_CATEGORY (ncc_debug);
+#define GST_CAT_DEFAULT (ncc_debug)
+
+/* the select call is also performed on the control sockets, that way
+ * we can send special commands to unblock or restart the select call */
+#define CONTROL_RESTART        'R'      /* restart the select call */
+#define CONTROL_STOP           'S'      /* stop the select call */
+#define CONTROL_SOCKETS(self)   self->control_sock
+#define WRITE_SOCKET(self)      self->control_sock[1]
+#define READ_SOCKET(self)       self->control_sock[0]
+
+#define SEND_COMMAND(self, command)             	\
+G_STMT_START {                                 	\
+  unsigned char c; c = command;                	\
+  write (WRITE_SOCKET(self), &c, 1);         	\
+} G_STMT_END
+
+#define READ_COMMAND(self, command, res)        	\
+G_STMT_START {                                	\
+  res = read(READ_SOCKET(self), &command, 1);    \
+} G_STMT_END
+
+#define DEFAULT_ADDRESS		"127.0.0.1"
+#define DEFAULT_PORT		5637
+#define DEFAULT_WINDOW_SIZE	32
+#define DEFAULT_TIMEOUT		GST_SECOND
+
+enum
+{
+  PROP_0,
+  PROP_ADDRESS,
+  PROP_PORT,
+  PROP_WINDOW_SIZE,
+  PROP_TIMEOUT
+};
+
+#define _do_init(type) \
+  GST_DEBUG_CATEGORY_INIT (ncc_debug, "netclock", 0, "Network client clock");
+
+GST_BOILERPLATE_FULL (GstNetClientClock, gst_net_client_clock,
+    GstSystemClock, GST_TYPE_SYSTEM_CLOCK, _do_init);
+
+static void gst_net_client_clock_finalize (GObject * object);
+static void gst_net_client_clock_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_net_client_clock_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+
+static void gst_net_client_clock_stop (GstNetClientClock * self);
+
+static void
+gst_net_client_clock_base_init (gpointer g_class)
+{
+  /* nop */
+}
+
+static void
+gst_net_client_clock_class_init (GstNetClientClockClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  gobject_class->finalize = gst_net_client_clock_finalize;
+  gobject_class->get_property = gst_net_client_clock_get_property;
+  gobject_class->set_property = gst_net_client_clock_set_property;
+
+  g_object_class_install_property (gobject_class, PROP_ADDRESS,
+      g_param_spec_string ("address", "address",
+          "The address of the machine providing a time server, "
+          "as a dotted quad (x.x.x.x)", DEFAULT_ADDRESS, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_PORT,
+      g_param_spec_int ("port", "port",
+          "The port on which the remote server is listenind", 0, 32768,
+          DEFAULT_PORT, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_WINDOW_SIZE,
+      g_param_spec_int ("window-size", "Window size",
+          "The size of the window used to calculate rate and offset", 2, 1024,
+          DEFAULT_WINDOW_SIZE, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_TIMEOUT,
+      g_param_spec_uint64 ("timeout", "Timeout",
+          "The amount of time, in nanoseconds, to wait for replies", 0,
+          G_MAXUINT64, DEFAULT_TIMEOUT, G_PARAM_READWRITE));
+}
+
+static void
+gst_net_client_clock_init (GstNetClientClock * self,
+    GstNetClientClockClass * g_class)
+{
+  self->port = DEFAULT_PORT;
+  self->address = g_strdup (DEFAULT_ADDRESS);
+  self->window_size = DEFAULT_WINDOW_SIZE;
+  self->timeout = DEFAULT_TIMEOUT;
+
+  self->sock = -1;
+  self->thread = NULL;
+
+  self->filling = TRUE;
+  self->time_index = 0;
+  self->local_times = g_new0 (GstClockTime, self->window_size);
+  self->remote_times = g_new0 (GstClockTime, self->window_size);
+
+  self->servaddr = NULL;
+
+  READ_SOCKET (self) = -1;
+  WRITE_SOCKET (self) = -1;
+}
+
+static void
+gst_net_client_clock_finalize (GObject * object)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+
+  if (self->thread) {
+    gst_net_client_clock_stop (self);
+    g_assert (self->thread == NULL);
+  }
+
+  if (READ_SOCKET (self) != -1) {
+    close (READ_SOCKET (self));
+    close (WRITE_SOCKET (self));
+    READ_SOCKET (self) = -1;
+    WRITE_SOCKET (self) = -1;
+  }
+
+  g_free (self->address);
+  self->address = NULL;
+
+  g_free (self->servaddr);
+  self->servaddr = NULL;
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_net_client_clock_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+
+  switch (prop_id) {
+    case PROP_ADDRESS:
+      g_free (self->address);
+      if (g_value_get_string (value) == NULL)
+        self->address = g_strdup (DEFAULT_ADDRESS);
+      else
+        self->address = g_strdup (g_value_get_string (value));
+      break;
+    case PROP_PORT:
+      self->port = g_value_get_int (value);
+      break;
+    case PROP_WINDOW_SIZE:
+      self->window_size = g_value_get_int (value);
+      break;
+    case PROP_TIMEOUT:
+      self->timeout = g_value_get_uint64 (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_net_client_clock_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+
+  switch (prop_id) {
+    case PROP_ADDRESS:
+      g_value_set_string (value, self->address);
+      break;
+    case PROP_PORT:
+      g_value_set_int (value, self->port);
+      break;
+    case PROP_WINDOW_SIZE:
+      g_value_set_int (value, self->window_size);
+      break;
+    case PROP_TIMEOUT:
+      g_value_set_uint64 (value, self->timeout);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+/* http://mathworld.wolfram.com/LeastSquaresFitting.html */
+static void
+do_linear_regression (GstClockTime * x, GstClockTime * y, gint n, gdouble * m,
+    gdouble * b, gdouble * r_squared)
+{
+  gdouble sxx, syy, sxy, xbar, ybar;
+  gint i;
+
+  /* we lose precision with the doubles, but there's no other way except to use
+     ~80 bit arithmetic */
+  for (i = 0; i < n; i++) {
+    xbar += x[i];
+    ybar += y[i];
+  }
+  xbar /= n;
+  ybar /= n;
+
+  for (i = 0; i < n; i++) {
+    sxx += ((double) x[i]) * x[i];
+    syy += ((double) y[i]) * y[i];
+    sxy += ((double) x[i]) * y[i];
+  }
+  sxx -= ((double) n) * xbar * xbar;
+  syy -= ((double) n) * ybar * ybar;
+  sxy -= ((double) n) * xbar * ybar;
+
+  *m = sxy / sxx;
+  *b = ybar - xbar * *m;
+  *r_squared = (sxy * sxy) / (sxx * syy);
+}
+
+static void
+gst_net_client_clock_observe_times (GstNetClientClock * self,
+    GstClockTime local_1, GstClockTime remote, GstClockTime local_2)
+{
+  GstClockTime local_avg;
+  gdouble m, b, r_squared;
+
+  if (local_2 < local_1)
+    goto bogus_observation;
+
+  local_avg = (local_2 - local_1) / 2;
+
+  self->local_times[self->time_index] = local_avg;
+  self->remote_times[self->time_index] = remote;
+
+  self->time_index++;
+  if (self->time_index == self->window_size) {
+    self->filling = FALSE;
+    self->time_index = 0;
+  }
+
+  if (!self->filling || self->time_index >= 4) {
+    /* need to allow tuning of the "4" parameter -- means that we need 4 samples
+     * before beginning to adjust the clock */
+    do_linear_regression (self->local_times, self->remote_times,
+        self->filling ? self->time_index : self->window_size, &m, &b,
+        &r_squared);
+
+    GST_LOG_OBJECT (self, "adjusting clock to m=%g, b=%g (rsquared=%g)", m, b,
+        r_squared);
+
+    gst_clock_set_rate_offset (GST_CLOCK (self), m, b);
+  }
+
+  if (self->filling) {
+    self->current_timeout = 0;
+  } else {
+    /* geto formula */
+    self->current_timeout =
+        (1e-3 / (1 - MIN (r_squared, 0.99999))) * GST_SECOND;
+    self->current_timeout = MIN (self->current_timeout, self->timeout);
+  }
+
+  return;
+
+bogus_observation:
+  {
+    GST_WARNING_OBJECT (self, "time packet receive time < send time (%",
+        GST_TIME_FORMAT, " < %" GST_TIME_FORMAT ")", GST_TIME_ARGS (local_1),
+        GST_TIME_ARGS (local_2));
+    return;
+  }
+}
+
+static gint
+gst_net_client_clock_do_select (GstNetClientClock * self, fd_set * readfds)
+{
+  guint max_sock;
+  gint ret;
+
+  while (TRUE) {
+    FD_ZERO (readfds);
+    FD_SET (self->sock, readfds);
+    FD_SET (READ_SOCKET (self), readfds);
+    max_sock = MAX (self->sock, READ_SOCKET (self));
+
+    GST_LOG_OBJECT (self, "doing select");
+    {
+      GstClockTime diff;
+      GTimeVal tv;
+
+      diff = gst_clock_get_internal_time (GST_CLOCK (self));
+      GST_TIME_TO_TIMEVAL (self->current_timeout, tv);
+
+      ret = select (max_sock + 1, readfds, NULL, NULL, (struct timeval *) &tv);
+
+      diff = gst_clock_get_internal_time (GST_CLOCK (self)) - diff;
+
+      if (diff > self->current_timeout)
+        self->current_timeout = 0;
+      else
+        self->current_timeout -= diff;
+    }
+    GST_LOG_OBJECT (self, "select returned %d", ret);
+
+    if (ret < 0) {
+      if (errno != EAGAIN && errno != EINTR)
+        goto select_error;
+      else
+        continue;
+    } else {
+      return ret;
+    }
+
+    g_assert_not_reached ();
+
+    /* log errors and keep going */
+  select_error:
+    {
+      GST_WARNING_OBJECT (self, "select error %d: %s (%d)", ret,
+          g_strerror (errno), errno);
+      continue;
+    }
+  }
+
+  g_assert_not_reached ();
+  return -1;
+}
+
+static gpointer
+gst_net_client_clock_thread (gpointer data)
+{
+  GstNetClientClock *self = data;
+  struct sockaddr_in tmpaddr;
+  socklen_t len;
+  fd_set read_fds;
+  GstNetTimePacket *packet;
+  gint ret;
+
+  while (TRUE) {
+    ret = gst_net_client_clock_do_select (self, &read_fds);
+
+    if (FD_ISSET (READ_SOCKET (self), &read_fds)) {
+      /* got control message */
+      while (TRUE) {
+        gchar command;
+        int res;
+
+        READ_COMMAND (self, command, res);
+        if (res < 0) {
+          GST_LOG_OBJECT (self, "no more commands");
+          break;
+        }
+
+        switch (command) {
+          case CONTROL_STOP:
+            /* break out of the select loop */
+            GST_LOG_OBJECT (self, "stop");
+            goto stopped;
+          default:
+            GST_WARNING_OBJECT (self, "unknown message: '%c'", command);
+            g_warning ("netclientclock: unknown control message received");
+            continue;
+        }
+
+        g_assert_not_reached ();
+      }
+
+      continue;
+    } else if (ret == 0) {
+      /* timed out, let's send another packet */
+      packet = gst_net_time_packet_new (NULL);
+
+      packet->local_time = gst_clock_get_internal_time (GST_CLOCK (self));
+
+      gst_net_time_packet_send (packet, self->sock,
+          (struct sockaddr *) self->servaddr, sizeof (struct sockaddr_in));
+
+      g_free (packet);
+
+      /* reset timeout */
+      self->current_timeout = self->timeout;
+    } else if (FD_ISSET (READ_SOCKET (self), &read_fds)) {
+      /* got data in */
+      GstClockTime new_local = gst_clock_get_internal_time (GST_CLOCK (self));
+
+      len = sizeof (struct sockaddr);
+      packet = gst_net_time_packet_receive (self->sock,
+          (struct sockaddr *) &tmpaddr, &len);
+
+      if (!packet)
+        goto receive_error;
+
+      /* observe_times will reset the timeout */
+      gst_net_client_clock_observe_times (self, packet->local_time,
+          packet->remote_time, new_local);
+
+      g_free (packet);
+      continue;
+    } else {
+      GST_WARNING_OBJECT (self, "unhandled select return state?");
+      continue;
+    }
+
+    g_assert_not_reached ();
+
+  stopped:
+    {
+      GST_DEBUG_OBJECT (self, "shutting down");
+      /* close socket */
+      return NULL;
+    }
+  receive_error:
+    {
+      GST_WARNING_OBJECT (self, "receive error");
+      continue;
+    }
+
+    g_assert_not_reached ();
+
+  }
+
+  g_assert_not_reached ();
+
+  return NULL;
+}
+
+static gboolean
+gst_net_client_clock_start (GstNetClientClock * self)
+{
+  struct sockaddr_in servaddr, myaddr;
+  socklen_t len;
+  gint ret;
+  GError *error;
+
+  g_return_val_if_fail (self->address != NULL, FALSE);
+  g_return_val_if_fail (self->servaddr == NULL, FALSE);
+
+  if ((ret = socket (AF_INET, SOCK_DGRAM, 0)) < 0)
+    goto no_socket;
+
+  self->sock = ret;
+
+  len = sizeof (myaddr);
+  ret = getsockname (self->sock, (struct sockaddr *) &myaddr, &len);
+  if (ret < 0)
+    goto getsockname_error;
+
+  GST_DEBUG_OBJECT (self, "socket opened on UDP port %hd",
+      ntohs (servaddr.sin_port));
+
+  memset (&servaddr, 0, sizeof (servaddr));
+  servaddr.sin_family = AF_INET;        /* host byte order */
+  servaddr.sin_port = htons (self->port);       /* short, network byte order */
+  if (!inet_aton (self->address, &servaddr.sin_addr))
+    goto bad_address;
+
+  self->servaddr = g_malloc (sizeof (struct sockaddr_in));
+  memcpy (self->servaddr, &servaddr, sizeof (servaddr));
+
+  GST_DEBUG_OBJECT (self, "will communicate with %s:%d", self->address,
+      self->port);
+
+  self->thread = g_thread_create (gst_net_client_clock_thread, self, TRUE,
+      &error);
+  if (!self->thread)
+    goto no_thread;
+
+  return TRUE;
+
+  /* ERRORS */
+no_socket:
+  {
+    GST_ERROR_OBJECT (self, "socket failed %d: %s (%d)", ret,
+        g_strerror (errno), errno);
+    return FALSE;
+  }
+getsockname_error:
+  {
+    GST_ERROR_OBJECT (self, "getsockname failed %d: %s (%d)", ret,
+        g_strerror (errno), errno);
+    close (self->sock);
+    self->sock = -1;
+    return FALSE;
+  }
+bad_address:
+  {
+    GST_ERROR_OBJECT (self, "inet_aton failed %d: %s (%d)", ret,
+        g_strerror (errno), errno);
+    close (self->sock);
+    self->sock = -1;
+    return FALSE;
+  }
+no_thread:
+  {
+    GST_ERROR_OBJECT (self, "could not create thread: %s", error->message);
+    close (self->sock);
+    self->sock = -1;
+    g_free (self->servaddr);
+    self->servaddr = NULL;
+    g_error_free (error);
+    return FALSE;
+  }
+}
+
+static void
+gst_net_client_clock_stop (GstNetClientClock * self)
+{
+  SEND_COMMAND (self, CONTROL_STOP);
+  g_thread_join (self->thread);
+  self->thread = NULL;
+
+  if (self->sock != -1) {
+    close (self->sock);
+    self->sock = -1;
+  }
+}
+
+GstClock *
+gst_net_client_clock_new (gchar * name, const gchar * remote_address,
+    gint remote_port, GstClockTime base_time)
+{
+  GstNetClientClock *ret;
+  gint iret;
+
+  g_return_val_if_fail (remote_address != NULL, NULL);
+  g_return_val_if_fail (remote_port > 0, NULL);
+  g_return_val_if_fail (remote_port < 32768, NULL);
+  g_return_val_if_fail (base_time != GST_CLOCK_TIME_NONE, NULL);
+
+  ret = g_object_new (GST_TYPE_NET_CLIENT_CLOCK, "address", remote_address,
+      "port", remote_port, NULL);
+
+  GST_DEBUG_OBJECT (ret, "creating socket pair");
+  if ((iret = socketpair (PF_UNIX, SOCK_STREAM, 0, CONTROL_SOCKETS (ret))) < 0)
+    goto no_socket_pair;
+
+  fcntl (READ_SOCKET (ret), F_SETFL, O_NONBLOCK);
+  fcntl (WRITE_SOCKET (ret), F_SETFL, O_NONBLOCK);
+
+  if (!gst_net_client_clock_start (ret))
+    goto failed_start;
+
+  /* all systems go, cap'n */
+  return (GstClock *) ret;
+
+no_socket_pair:
+  {
+    GST_ERROR_OBJECT (ret, "no socket pair %d: %s (%d)", iret,
+        g_strerror (errno), errno);
+    gst_object_unref (ret);
+    return NULL;
+  }
+failed_start:
+  {
+    /* already printed a nice error */
+    gst_object_unref (ret);
+    return NULL;
+  }
+}

gst/net/gstnetclientclock.h

@@ -0,0 +1,99 @@
+/* GStreamer
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2005 Wim Taymans <wim@fluendo.com>
+ *                    2005 Andy Wingo <wingo@pobox.com>
+ *
+ * gstnetclientclock.h: clock that synchronizes itself to a time provider over
+ * the network
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#ifndef __GST_NET_CLIENT_CLOCK_H__
+#define __GST_NET_CLIENT_CLOCK_H__
+
+#include <gst/gst.h>
+#include <gst/gstsystemclock.h>
+
+G_BEGIN_DECLS
+
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <netdb.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <fcntl.h>
+
+#define GST_TYPE_NET_CLIENT_CLOCK \
+  (gst_net_client_clock_get_type())
+#define GST_NET_CLIENT_CLOCK(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_NET_CLIENT_CLOCK,GstNetClientClock))
+#define GST_NET_CLIENT_CLOCK_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_NET_CLIENT_CLOCK,GstNetClientClockClass))
+#define GST_IS_NET_CLIENT_CLOCK(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_NET_CLIENT_CLOCK))
+#define GST_IS_NET_CLIENT_CLOCK_CLASS(obj) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_NET_CLIENT_CLOCK))
+
+typedef struct _GstNetClientClock GstNetClientClock;
+typedef struct _GstNetClientClockClass GstNetClientClockClass;
+
+struct _GstNetClientClock {
+  GstSystemClock clock;
+
+  /*< protected >*/
+  gchar *address;
+  gint port;
+  
+  gint window_size;
+  GstClockTime timeout;
+
+  /*< private >*/
+  int sock;
+  int control_sock[2];
+
+  GstClockTime current_timeout;
+
+  gboolean filling;
+  gint time_index;
+  GstClockTime *local_times;
+  GstClockTime *remote_times;
+
+  struct sockaddr_id *servaddr;
+
+  GThread *thread;
+
+  gpointer _gst_reserved[GST_PADDING];
+};
+
+struct _GstNetClientClockClass {
+  GstSystemClockClass parent_class;
+
+  /*< private >*/
+  gpointer _gst_reserved[GST_PADDING];
+};
+
+GType           gst_net_client_clock_get_type	(void);
+GstClock*	gst_net_client_clock_new	(gchar *name, const gchar *remote_address,
+                                                 gint remote_port, GstClockTime base_time);
+
+G_END_DECLS
+
+#endif /* __GST_NET_CLIENT_CLOCK_H__ */

libs/gst/net/Makefile.am

@@ -5,10 +5,12 @@ lib_LTLIBRARIES = libgstnet-tempname-@GST_MAJORMINOR@.la
 libgstnet_tempname_@GST_MAJORMINOR@_includedir = $(includedir)/gstreamer-@GST_MAJORMINOR@/gst/net
 libgstnet_tempname_@GST_MAJORMINOR@_include_HEADERS = \
     gstnet.h \
+    gstnetclientclock.h \
     gstnettimepacket.h \
     gstnettimeprovider.h
 
 libgstnet_tempname_@GST_MAJORMINOR@_la_SOURCES = \
+    gstnetclientclock.c \
     gstnettimepacket.c \
     gstnettimeprovider.c
 

libs/gst/net/gstnet.h

@@ -22,6 +22,7 @@
 #define __GST_NET_H__
 
 
+#include <gst/net/gstnetclientclock.h>
 #include <gst/net/gstnettimepacket.h>
 #include <gst/net/gstnettimeprovider.h>
 

libs/gst/net/gstnetclientclock.c

@@ -0,0 +1,592 @@
+/* GStreamer
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2005 Wim Taymans <wim@fluendo.com>
+ *                    2005 Andy Wingo <wingo@pobox.com>
+ *
+ * gstnetclientclock.h: clock that synchronizes itself to a time provider over
+ * the network
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <unistd.h>
+
+#include "gstnettimepacket.h"
+#include "gstnetclientclock.h"
+
+GST_DEBUG_CATEGORY (ncc_debug);
+#define GST_CAT_DEFAULT (ncc_debug)
+
+/* the select call is also performed on the control sockets, that way
+ * we can send special commands to unblock or restart the select call */
+#define CONTROL_RESTART        'R'      /* restart the select call */
+#define CONTROL_STOP           'S'      /* stop the select call */
+#define CONTROL_SOCKETS(self)   self->control_sock
+#define WRITE_SOCKET(self)      self->control_sock[1]
+#define READ_SOCKET(self)       self->control_sock[0]
+
+#define SEND_COMMAND(self, command)             	\
+G_STMT_START {                                 	\
+  unsigned char c; c = command;                	\
+  write (WRITE_SOCKET(self), &c, 1);         	\
+} G_STMT_END
+
+#define READ_COMMAND(self, command, res)        	\
+G_STMT_START {                                	\
+  res = read(READ_SOCKET(self), &command, 1);    \
+} G_STMT_END
+
+#define DEFAULT_ADDRESS		"127.0.0.1"
+#define DEFAULT_PORT		5637
+#define DEFAULT_WINDOW_SIZE	32
+#define DEFAULT_TIMEOUT		GST_SECOND
+
+enum
+{
+  PROP_0,
+  PROP_ADDRESS,
+  PROP_PORT,
+  PROP_WINDOW_SIZE,
+  PROP_TIMEOUT
+};
+
+#define _do_init(type) \
+  GST_DEBUG_CATEGORY_INIT (ncc_debug, "netclock", 0, "Network client clock");
+
+GST_BOILERPLATE_FULL (GstNetClientClock, gst_net_client_clock,
+    GstSystemClock, GST_TYPE_SYSTEM_CLOCK, _do_init);
+
+static void gst_net_client_clock_finalize (GObject * object);
+static void gst_net_client_clock_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_net_client_clock_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+
+static void gst_net_client_clock_stop (GstNetClientClock * self);
+
+static void
+gst_net_client_clock_base_init (gpointer g_class)
+{
+  /* nop */
+}
+
+static void
+gst_net_client_clock_class_init (GstNetClientClockClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  gobject_class->finalize = gst_net_client_clock_finalize;
+  gobject_class->get_property = gst_net_client_clock_get_property;
+  gobject_class->set_property = gst_net_client_clock_set_property;
+
+  g_object_class_install_property (gobject_class, PROP_ADDRESS,
+      g_param_spec_string ("address", "address",
+          "The address of the machine providing a time server, "
+          "as a dotted quad (x.x.x.x)", DEFAULT_ADDRESS, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_PORT,
+      g_param_spec_int ("port", "port",
+          "The port on which the remote server is listenind", 0, 32768,
+          DEFAULT_PORT, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_WINDOW_SIZE,
+      g_param_spec_int ("window-size", "Window size",
+          "The size of the window used to calculate rate and offset", 2, 1024,
+          DEFAULT_WINDOW_SIZE, G_PARAM_READWRITE));
+  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_TIMEOUT,
+      g_param_spec_uint64 ("timeout", "Timeout",
+          "The amount of time, in nanoseconds, to wait for replies", 0,
+          G_MAXUINT64, DEFAULT_TIMEOUT, G_PARAM_READWRITE));
+}
+
+static void
+gst_net_client_clock_init (GstNetClientClock * self,
+    GstNetClientClockClass * g_class)
+{
+  self->port = DEFAULT_PORT;
+  self->address = g_strdup (DEFAULT_ADDRESS);
+  self->window_size = DEFAULT_WINDOW_SIZE;
+  self->timeout = DEFAULT_TIMEOUT;
+
+  self->sock = -1;
+  self->thread = NULL;
+
+  self->filling = TRUE;
+  self->time_index = 0;
+  self->local_times = g_new0 (GstClockTime, self->window_size);
+  self->remote_times = g_new0 (GstClockTime, self->window_size);
+
+  self->servaddr = NULL;
+
+  READ_SOCKET (self) = -1;
+  WRITE_SOCKET (self) = -1;
+}
+
+static void
+gst_net_client_clock_finalize (GObject * object)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+
+  if (self->thread) {
+    gst_net_client_clock_stop (self);
+    g_assert (self->thread == NULL);
+  }
+
+  if (READ_SOCKET (self) != -1) {
+    close (READ_SOCKET (self));
+    close (WRITE_SOCKET (self));
+    READ_SOCKET (self) = -1;
+    WRITE_SOCKET (self) = -1;
+  }
+
+  g_free (self->address);
+  self->address = NULL;
+
+  g_free (self->servaddr);
+  self->servaddr = NULL;
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_net_client_clock_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+
+  switch (prop_id) {
+    case PROP_ADDRESS:
+      g_free (self->address);
+      if (g_value_get_string (value) == NULL)
+        self->address = g_strdup (DEFAULT_ADDRESS);
+      else
+        self->address = g_strdup (g_value_get_string (value));
+      break;
+    case PROP_PORT:
+      self->port = g_value_get_int (value);
+      break;
+    case PROP_WINDOW_SIZE:
+      self->window_size = g_value_get_int (value);
+      break;
+    case PROP_TIMEOUT:
+      self->timeout = g_value_get_uint64 (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_net_client_clock_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
+
+  switch (prop_id) {
+    case PROP_ADDRESS:
+      g_value_set_string (value, self->address);
+      break;
+    case PROP_PORT:
+      g_value_set_int (value, self->port);
+      break;
+    case PROP_WINDOW_SIZE:
+      g_value_set_int (value, self->window_size);
+      break;
+    case PROP_TIMEOUT:
+      g_value_set_uint64 (value, self->timeout);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+/* http://mathworld.wolfram.com/LeastSquaresFitting.html */
+static void
+do_linear_regression (GstClockTime * x, GstClockTime * y, gint n, gdouble * m,
+    gdouble * b, gdouble * r_squared)
+{
+  gdouble sxx, syy, sxy, xbar, ybar;
+  gint i;
+
+  /* we lose precision with the doubles, but there's no other way except to use
+     ~80 bit arithmetic */
+  for (i = 0; i < n; i++) {
+    xbar += x[i];
+    ybar += y[i];
+  }
+  xbar /= n;
+  ybar /= n;
+
+  for (i = 0; i < n; i++) {
+    sxx += ((double) x[i]) * x[i];
+    syy += ((double) y[i]) * y[i];
+    sxy += ((double) x[i]) * y[i];
+  }
+  sxx -= ((double) n) * xbar * xbar;
+  syy -= ((double) n) * ybar * ybar;
+  sxy -= ((double) n) * xbar * ybar;
+
+  *m = sxy / sxx;
+  *b = ybar - xbar * *m;
+  *r_squared = (sxy * sxy) / (sxx * syy);
+}
+
+static void
+gst_net_client_clock_observe_times (GstNetClientClock * self,
+    GstClockTime local_1, GstClockTime remote, GstClockTime local_2)
+{
+  GstClockTime local_avg;
+  gdouble m, b, r_squared;
+
+  if (local_2 < local_1)
+    goto bogus_observation;
+
+  local_avg = (local_2 - local_1) / 2;
+
+  self->local_times[self->time_index] = local_avg;
+  self->remote_times[self->time_index] = remote;
+
+  self->time_index++;
+  if (self->time_index == self->window_size) {
+    self->filling = FALSE;
+    self->time_index = 0;
+  }
+
+  if (!self->filling || self->time_index >= 4) {
+    /* need to allow tuning of the "4" parameter -- means that we need 4 samples
+     * before beginning to adjust the clock */
+    do_linear_regression (self->local_times, self->remote_times,
+        self->filling ? self->time_index : self->window_size, &m, &b,
+        &r_squared);
+
+    GST_LOG_OBJECT (self, "adjusting clock to m=%g, b=%g (rsquared=%g)", m, b,
+        r_squared);
+
+    gst_clock_set_rate_offset (GST_CLOCK (self), m, b);
+  }
+
+  if (self->filling) {
+    self->current_timeout = 0;
+  } else {
+    /* geto formula */
+    self->current_timeout =
+        (1e-3 / (1 - MIN (r_squared, 0.99999))) * GST_SECOND;
+    self->current_timeout = MIN (self->current_timeout, self->timeout);
+  }
+
+  return;
+
+bogus_observation:
+  {
+    GST_WARNING_OBJECT (self, "time packet receive time < send time (%",
+        GST_TIME_FORMAT, " < %" GST_TIME_FORMAT ")", GST_TIME_ARGS (local_1),
+        GST_TIME_ARGS (local_2));
+    return;
+  }
+}
+
+static gint
+gst_net_client_clock_do_select (GstNetClientClock * self, fd_set * readfds)
+{
+  guint max_sock;
+  gint ret;
+
+  while (TRUE) {
+    FD_ZERO (readfds);
+    FD_SET (self->sock, readfds);
+    FD_SET (READ_SOCKET (self), readfds);
+    max_sock = MAX (self->sock, READ_SOCKET (self));
+
+    GST_LOG_OBJECT (self, "doing select");
+    {
+      GstClockTime diff;
+      GTimeVal tv;
+
+      diff = gst_clock_get_internal_time (GST_CLOCK (self));
+      GST_TIME_TO_TIMEVAL (self->current_timeout, tv);
+
+      ret = select (max_sock + 1, readfds, NULL, NULL, (struct timeval *) &tv);
+
+      diff = gst_clock_get_internal_time (GST_CLOCK (self)) - diff;
+
+      if (diff > self->current_timeout)
+        self->current_timeout = 0;
+      else
+        self->current_timeout -= diff;
+    }
+    GST_LOG_OBJECT (self, "select returned %d", ret);
+
+    if (ret < 0) {
+      if (errno != EAGAIN && errno != EINTR)
+        goto select_error;
+      else
+        continue;
+    } else {
+      return ret;
+    }
+
+    g_assert_not_reached ();
+
+    /* log errors and keep going */
+  select_error:
+    {
+      GST_WARNING_OBJECT (self, "select error %d: %s (%d)", ret,
+          g_strerror (errno), errno);
+      continue;
+    }
+  }
+
+  g_assert_not_reached ();
+  return -1;
+}
+
+static gpointer
+gst_net_client_clock_thread (gpointer data)
+{
+  GstNetClientClock *self = data;
+  struct sockaddr_in tmpaddr;
+  socklen_t len;
+  fd_set read_fds;
+  GstNetTimePacket *packet;
+  gint ret;
+
+  while (TRUE) {
+    ret = gst_net_client_clock_do_select (self, &read_fds);
+
+    if (FD_ISSET (READ_SOCKET (self), &read_fds)) {
+      /* got control message */
+      while (TRUE) {
+        gchar command;
+        int res;
+
+        READ_COMMAND (self, command, res);
+        if (res < 0) {
+          GST_LOG_OBJECT (self, "no more commands");
+          break;
+        }
+
+        switch (command) {
+          case CONTROL_STOP:
+            /* break out of the select loop */
+            GST_LOG_OBJECT (self, "stop");
+            goto stopped;
+          default:
+            GST_WARNING_OBJECT (self, "unknown message: '%c'", command);
+            g_warning ("netclientclock: unknown control message received");
+            continue;
+        }
+
+        g_assert_not_reached ();
+      }
+
+      continue;
+    } else if (ret == 0) {
+      /* timed out, let's send another packet */
+      packet = gst_net_time_packet_new (NULL);
+
+      packet->local_time = gst_clock_get_internal_time (GST_CLOCK (self));
+
+      gst_net_time_packet_send (packet, self->sock,
+          (struct sockaddr *) self->servaddr, sizeof (struct sockaddr_in));
+
+      g_free (packet);
+
+      /* reset timeout */
+      self->current_timeout = self->timeout;
+    } else if (FD_ISSET (READ_SOCKET (self), &read_fds)) {
+      /* got data in */
+      GstClockTime new_local = gst_clock_get_internal_time (GST_CLOCK (self));
+
+      len = sizeof (struct sockaddr);
+      packet = gst_net_time_packet_receive (self->sock,
+          (struct sockaddr *) &tmpaddr, &len);
+
+      if (!packet)
+        goto receive_error;
+
+      /* observe_times will reset the timeout */
+      gst_net_client_clock_observe_times (self, packet->local_time,
+          packet->remote_time, new_local);
+
+      g_free (packet);
+      continue;
+    } else {
+      GST_WARNING_OBJECT (self, "unhandled select return state?");
+      continue;
+    }
+
+    g_assert_not_reached ();
+
+  stopped:
+    {
+      GST_DEBUG_OBJECT (self, "shutting down");
+      /* close socket */
+      return NULL;
+    }
+  receive_error:
+    {
+      GST_WARNING_OBJECT (self, "receive error");
+      continue;
+    }
+
+    g_assert_not_reached ();
+
+  }
+
+  g_assert_not_reached ();
+
+  return NULL;
+}
+
+static gboolean
+gst_net_client_clock_start (GstNetClientClock * self)
+{
+  struct sockaddr_in servaddr, myaddr;
+  socklen_t len;
+  gint ret;
+  GError *error;
+
+  g_return_val_if_fail (self->address != NULL, FALSE);
+  g_return_val_if_fail (self->servaddr == NULL, FALSE);
+
+  if ((ret = socket (AF_INET, SOCK_DGRAM, 0)) < 0)
+    goto no_socket;
+
+  self->sock = ret;
+
+  len = sizeof (myaddr);
+  ret = getsockname (self->sock, (struct sockaddr *) &myaddr, &len);
+  if (ret < 0)
+    goto getsockname_error;
+
+  GST_DEBUG_OBJECT (self, "socket opened on UDP port %hd",
+      ntohs (servaddr.sin_port));
+
+  memset (&servaddr, 0, sizeof (servaddr));
+  servaddr.sin_family = AF_INET;        /* host byte order */
+  servaddr.sin_port = htons (self->port);       /* short, network byte order */
+  if (!inet_aton (self->address, &servaddr.sin_addr))
+    goto bad_address;
+
+  self->servaddr = g_malloc (sizeof (struct sockaddr_in));
+  memcpy (self->servaddr, &servaddr, sizeof (servaddr));
+
+  GST_DEBUG_OBJECT (self, "will communicate with %s:%d", self->address,
+      self->port);
+
+  self->thread = g_thread_create (gst_net_client_clock_thread, self, TRUE,
+      &error);
+  if (!self->thread)
+    goto no_thread;
+
+  return TRUE;
+
+  /* ERRORS */
+no_socket:
+  {
+    GST_ERROR_OBJECT (self, "socket failed %d: %s (%d)", ret,
+        g_strerror (errno), errno);
+    return FALSE;
+  }
+getsockname_error:
+  {
+    GST_ERROR_OBJECT (self, "getsockname failed %d: %s (%d)", ret,
+        g_strerror (errno), errno);
+    close (self->sock);
+    self->sock = -1;
+    return FALSE;
+  }
+bad_address:
+  {
+    GST_ERROR_OBJECT (self, "inet_aton failed %d: %s (%d)", ret,
+        g_strerror (errno), errno);
+    close (self->sock);
+    self->sock = -1;
+    return FALSE;
+  }
+no_thread:
+  {
+    GST_ERROR_OBJECT (self, "could not create thread: %s", error->message);
+    close (self->sock);
+    self->sock = -1;
+    g_free (self->servaddr);
+    self->servaddr = NULL;
+    g_error_free (error);
+    return FALSE;
+  }
+}
+
+static void
+gst_net_client_clock_stop (GstNetClientClock * self)
+{
+  SEND_COMMAND (self, CONTROL_STOP);
+  g_thread_join (self->thread);
+  self->thread = NULL;
+
+  if (self->sock != -1) {
+    close (self->sock);
+    self->sock = -1;
+  }
+}
+
+GstClock *
+gst_net_client_clock_new (gchar * name, const gchar * remote_address,
+    gint remote_port, GstClockTime base_time)
+{
+  GstNetClientClock *ret;
+  gint iret;
+
+  g_return_val_if_fail (remote_address != NULL, NULL);
+  g_return_val_if_fail (remote_port > 0, NULL);
+  g_return_val_if_fail (remote_port < 32768, NULL);
+  g_return_val_if_fail (base_time != GST_CLOCK_TIME_NONE, NULL);
+
+  ret = g_object_new (GST_TYPE_NET_CLIENT_CLOCK, "address", remote_address,
+      "port", remote_port, NULL);
+
+  GST_DEBUG_OBJECT (ret, "creating socket pair");
+  if ((iret = socketpair (PF_UNIX, SOCK_STREAM, 0, CONTROL_SOCKETS (ret))) < 0)
+    goto no_socket_pair;
+
+  fcntl (READ_SOCKET (ret), F_SETFL, O_NONBLOCK);
+  fcntl (WRITE_SOCKET (ret), F_SETFL, O_NONBLOCK);
+
+  if (!gst_net_client_clock_start (ret))
+    goto failed_start;
+
+  /* all systems go, cap'n */
+  return (GstClock *) ret;
+
+no_socket_pair:
+  {
+    GST_ERROR_OBJECT (ret, "no socket pair %d: %s (%d)", iret,
+        g_strerror (errno), errno);
+    gst_object_unref (ret);
+    return NULL;
+  }
+failed_start:
+  {
+    /* already printed a nice error */
+    gst_object_unref (ret);
+    return NULL;
+  }
+}

libs/gst/net/gstnetclientclock.h

@@ -0,0 +1,99 @@
+/* GStreamer
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2005 Wim Taymans <wim@fluendo.com>
+ *                    2005 Andy Wingo <wingo@pobox.com>
+ *
+ * gstnetclientclock.h: clock that synchronizes itself to a time provider over
+ * the network
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#ifndef __GST_NET_CLIENT_CLOCK_H__
+#define __GST_NET_CLIENT_CLOCK_H__
+
+#include <gst/gst.h>
+#include <gst/gstsystemclock.h>
+
+G_BEGIN_DECLS
+
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <netdb.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <fcntl.h>
+
+#define GST_TYPE_NET_CLIENT_CLOCK \
+  (gst_net_client_clock_get_type())
+#define GST_NET_CLIENT_CLOCK(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_NET_CLIENT_CLOCK,GstNetClientClock))
+#define GST_NET_CLIENT_CLOCK_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_NET_CLIENT_CLOCK,GstNetClientClockClass))
+#define GST_IS_NET_CLIENT_CLOCK(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_NET_CLIENT_CLOCK))
+#define GST_IS_NET_CLIENT_CLOCK_CLASS(obj) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_NET_CLIENT_CLOCK))
+
+typedef struct _GstNetClientClock GstNetClientClock;
+typedef struct _GstNetClientClockClass GstNetClientClockClass;
+
+struct _GstNetClientClock {
+  GstSystemClock clock;
+
+  /*< protected >*/
+  gchar *address;
+  gint port;
+  
+  gint window_size;
+  GstClockTime timeout;
+
+  /*< private >*/
+  int sock;
+  int control_sock[2];
+
+  GstClockTime current_timeout;
+
+  gboolean filling;
+  gint time_index;
+  GstClockTime *local_times;
+  GstClockTime *remote_times;
+
+  struct sockaddr_id *servaddr;
+
+  GThread *thread;
+
+  gpointer _gst_reserved[GST_PADDING];
+};
+
+struct _GstNetClientClockClass {
+  GstSystemClockClass parent_class;
+
+  /*< private >*/
+  gpointer _gst_reserved[GST_PADDING];
+};
+
+GType           gst_net_client_clock_get_type	(void);
+GstClock*	gst_net_client_clock_new	(gchar *name, const gchar *remote_address,
+                                                 gint remote_port, GstClockTime base_time);
+
+G_END_DECLS
+
+#endif /* __GST_NET_CLIENT_CLOCK_H__ */

tests/check/Makefile.am

@@ -57,6 +57,7 @@ check_PROGRAMS =				\
 	states/sinks				\
 	gst-libs/controller			\
 	gst-libs/gdp				\
+	net/gstnetclientclock			\
 	net/gstnettimeprovider
 
 TESTS = $(check_PROGRAMS)
@@ -79,6 +80,9 @@ gst_libs_controller_LDADD = \
 	$(top_builddir)/libs/gst/controller/libgstcontroller-@GST_MAJORMINOR@.la \
 	$(LDADD)
 
+net_gstnetclientclock_LDADD = \
+	$(top_builddir)/gst/net/libgstnet-tempname-@GST_MAJORMINOR@.la \
+	$(LDADD)
 net_gstnettimeprovider_LDADD = \
 	$(top_builddir)/gst/net/libgstnet-tempname-@GST_MAJORMINOR@.la \
 	$(LDADD)

tests/check/libs/gstnetclientclock.c

@@ -0,0 +1,137 @@
+/* GStreamer
+ * Copyright (C) 2005 Andy Wingo <wingo@pobox.com>
+ *
+ * gstnetclientclock.c: Unit test for the network client clock
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <gst/check/gstcheck.h>
+#include <gst/net/gstnet.h>
+
+#include <unistd.h>
+
+GST_START_TEST (test_instantiation)
+{
+  GstClock *client, *local;
+
+  local = gst_system_clock_obtain ();
+  client = gst_net_client_clock_new (NULL, "127.0.0.1", 1234, GST_SECOND);
+  fail_unless (local != NULL, "failed to get system clock");
+  fail_unless (client != NULL, "failed to get network client clock");
+
+  /* one for gstreamer, one for us */
+  ASSERT_OBJECT_REFCOUNT (local, "system clock", 2);
+  ASSERT_OBJECT_REFCOUNT (client, "network client clock", 1);
+
+  gst_object_unref (client);
+
+  ASSERT_OBJECT_REFCOUNT (local, "net time provider", 2);
+
+  gst_object_unref (local);
+}
+
+GST_END_TEST;
+
+#if 0
+GST_START_TEST (test_functioning)
+{
+  GstNetTimeProvider *ntp;
+  GstNetTimePacket *packet;
+  GstClock *clock;
+  GstClockTime local;
+  struct sockaddr_in servaddr;
+  gint port = -1, sockfd, ret;
+  socklen_t len;
+
+  clock = gst_system_clock_obtain ();
+  fail_unless (clock != NULL, "failed to get system clock");
+  ntp = gst_net_time_provider_new (clock, "127.0.0.1", -1);
+  fail_unless (ntp != NULL, "failed to create net time provider");
+
+  g_object_get (ntp, "port", &port, NULL);
+  fail_unless (port > 0);
+
+  sockfd = socket (AF_INET, SOCK_DGRAM, 0);
+  fail_if (sockfd < 0, "socket failed");
+
+  memset (&servaddr, 0, sizeof (servaddr));
+  servaddr.sin_family = AF_INET;
+  servaddr.sin_port = htons (port);
+  inet_aton ("127.0.0.1", &servaddr.sin_addr);
+
+  packet = gst_net_time_packet_new (NULL);
+  fail_unless (packet != NULL, "failed to create packet");
+
+  packet->local_time = local = gst_clock_get_time (clock);
+
+  len = sizeof (servaddr);
+  ret = gst_net_time_packet_send (packet, sockfd,
+      (struct sockaddr *) &servaddr, len);
+
+  fail_unless (ret == GST_NET_TIME_PACKET_SIZE, "failed to send packet");
+
+  g_free (packet);
+
+  packet = gst_net_time_packet_receive (sockfd, (struct sockaddr *) &servaddr,
+      &len);
+
+  fail_unless (packet != NULL, "failed to receive packet");
+  fail_unless (packet->local_time == local, "local time is not the same");
+  fail_unless (packet->remote_time > local, "remote time not after local time");
+  fail_unless (packet->remote_time < gst_clock_get_time (clock),
+      "remote time in the future");
+
+  g_free (packet);
+
+  close (sockfd);
+
+  gst_object_unref (ntp);
+  gst_object_unref (clock);
+}
+
+GST_END_TEST;
+#endif
+
+Suite *
+gst_net_client_clock_suite (void)
+{
+  Suite *s = suite_create ("GstNetClientClock");
+  TCase *tc_chain = tcase_create ("generic tests");
+
+  suite_add_tcase (s, tc_chain);
+  tcase_add_test (tc_chain, test_instantiation);
+  /* tcase_add_test (tc_chain, test_functioning); */
+
+  return s;
+}
+
+int
+main (int argc, char **argv)
+{
+  int nf;
+
+  Suite *s = gst_net_client_clock_suite ();
+  SRunner *sr = srunner_create (s);
+
+  gst_check_init (&argc, &argv);
+
+  srunner_run_all (sr, CK_NORMAL);
+  nf = srunner_ntests_failed (sr);
+  srunner_free (sr);
+
+  return nf;
+}

tests/check/libs/gstnettimeprovider.c

@@ -74,7 +74,7 @@ GST_START_TEST (test_functioning)
 
   memset (&servaddr, 0, sizeof (servaddr));
   servaddr.sin_family = AF_INET;
-  servaddr.sin_port = port;
+  servaddr.sin_port = htons (port);
   inet_aton ("127.0.0.1", &servaddr.sin_addr);
 
   packet = gst_net_time_packet_new (NULL);

tests/misc/network-clock-utils.scm

@@ -164,7 +164,7 @@
     (if (null? (q-tail q))
         (make-q tail)
         (let ((l (append! (q-head q) tail)))
-          (if (> (length (q-head q)) *queue-length*)
+          (if (> (length (q-head q)) *window-size*)
               (make-q (cdr (q-head q)))
               q)))))
 

tests/misc/network-clock.scm

@@ -125,7 +125,7 @@ exec guile --debug -l $0 -e main -- "$@"
            (lambda (m b r-squared)
              (define (next-time) 
                (max
-                (if (< (length (q-head x)) *queue-length*)
+                (if (< (length (q-head x)) *window-size*)
                     0
                     (/ 1 (- 1 (min r-squared 0.99999)) 1000))
                 0.10))
@@ -188,7 +188,7 @@ exec guile --debug -l $0 -e main -- "$@"
 (define-parameter *packet-loss* 0.01)
 (define-parameter *send-jitter* 0.1)
 (define-parameter *recv-jitter* 0.1)
-(define-parameter *queue-length* 32)
+(define-parameter *window-size* 32)
 (define-parameter *local-rate* 1.0)
 (define-parameter *remote-rate* 1.1)
 (define-parameter *total-time* 5.0)

tests/network-clock-utils.scm

@@ -164,7 +164,7 @@
     (if (null? (q-tail q))
         (make-q tail)
         (let ((l (append! (q-head q) tail)))
-          (if (> (length (q-head q)) *queue-length*)
+          (if (> (length (q-head q)) *window-size*)
               (make-q (cdr (q-head q)))
               q)))))
 

tests/network-clock.scm

@@ -125,7 +125,7 @@ exec guile --debug -l $0 -e main -- "$@"
            (lambda (m b r-squared)
              (define (next-time) 
                (max
-                (if (< (length (q-head x)) *queue-length*)
+                (if (< (length (q-head x)) *window-size*)
                     0
                     (/ 1 (- 1 (min r-squared 0.99999)) 1000))
                 0.10))
@@ -188,7 +188,7 @@ exec guile --debug -l $0 -e main -- "$@"
 (define-parameter *packet-loss* 0.01)
 (define-parameter *send-jitter* 0.1)
 (define-parameter *recv-jitter* 0.1)
-(define-parameter *queue-length* 32)
+(define-parameter *window-size* 32)
 (define-parameter *local-rate* 1.0)
 (define-parameter *remote-rate* 1.1)
 (define-parameter *total-time* 5.0)