gstreamer/libs/gst/net/gstntppacket.c
2017-10-03 13:54:25 -07:00

376 lines
11 KiB
C

/* GStreamer
* Copyright (C) 2005 Andy Wingo <wingo@pobox.com>
* Copyright (C) 2010 Tim-Philipp Müller <tim centricular net>
* Copyright (C) 2012 Collabora Ltd. <tim.muller@collabora.co.uk>
* Copyright (C) 2015 Sebastian Dröge <sebastian@centricular.com>
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/* THIS IS A PRIVATE API
* SECTION:gstntppacket
* @short_description: Helper structure to construct clock packets used
* by network clocks for NTPv4.
* @see_also: #GstClock, #GstNetClientClock, #GstNtpClock
*
* Various functions for receiving, sending an serializing #GstNtpPacket
* structures.
*/
/* FIXME 2.0: Merge this with GstNetTimePacket! */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <glib.h>
#ifdef __CYGWIN__
# include <unistd.h>
# include <fcntl.h>
#endif
#include <gst/gst.h>
#include <string.h>
#include "gstntppacket.h"
G_DEFINE_BOXED_TYPE (GstNtpPacket, gst_ntp_packet,
gst_ntp_packet_copy, gst_ntp_packet_free);
static inline GstClockTime
ntp_timestamp_to_gst_clock_time (guint32 seconds, guint32 fraction)
{
return gst_util_uint64_scale (seconds, GST_SECOND, 1) +
gst_util_uint64_scale (fraction, GST_SECOND,
G_GUINT64_CONSTANT (1) << 32);
}
static inline guint32
gst_clock_time_to_ntp_timestamp_seconds (GstClockTime gst)
{
GstClockTime seconds = gst_util_uint64_scale (gst, 1, GST_SECOND);
return seconds;
}
static inline guint32
gst_clock_time_to_ntp_timestamp_fraction (GstClockTime gst)
{
GstClockTime seconds = gst_util_uint64_scale (gst, 1, GST_SECOND);
return gst_util_uint64_scale (gst - seconds, G_GUINT64_CONSTANT (1) << 32,
GST_SECOND);
}
/**
* gst_ntp_packet_new:
* @buffer: (array): a buffer from which to construct the packet, or NULL
* @error: a #GError
*
* Creates a new #GstNtpPacket from a buffer received over the network. The
* caller is responsible for ensuring that @buffer is at least
* #GST_NTP_PACKET_SIZE bytes long.
*
* If @buffer is %NULL, the local and remote times will be set to
* #GST_CLOCK_TIME_NONE.
*
* MT safe. Caller owns return value (gst_ntp_packet_free to free).
*
* Returns: The new #GstNtpPacket.
*/
GstNtpPacket *
gst_ntp_packet_new (const guint8 * buffer, GError ** error)
{
GstNtpPacket *ret;
g_assert (sizeof (GstClockTime) == 8);
if (buffer) {
guint8 version = (buffer[0] >> 3) & 0x7;
guint8 stratum = buffer[1];
gint8 poll_interval = buffer[2];
if (version != 4) {
g_set_error (error, GST_NTP_ERROR, GST_NTP_ERROR_WRONG_VERSION,
"Invalid NTP version %d", version);
return NULL;
}
/* Kiss-o'-Death packet! */
if (stratum == 0) {
gchar code[5] = { buffer[3 * 4 + 0], buffer[3 * 4 + 1], buffer[3 * 4 + 2],
buffer[3 * 4 + 3], 0
};
/* AUTH, AUTO, CRYP, DENY, RSTR, NKEY => DENY */
if (strcmp (code, "AUTH") == 0 ||
strcmp (code, "AUTO") == 0 ||
strcmp (code, "CRYP") == 0 ||
strcmp (code, "DENY") == 0 ||
strcmp (code, "RSTR") == 0 || strcmp (code, "NKEY") == 0) {
g_set_error (error, GST_NTP_ERROR, GST_NTP_ERROR_KOD_DENY,
"Kiss-o'-Death denied '%s'", code);
} else if (strcmp (code, "RATE") == 0) {
g_set_error (error, GST_NTP_ERROR, GST_NTP_ERROR_KOD_RATE,
"Kiss-o'-Death '%s'", code);
} else {
g_set_error (error, GST_NTP_ERROR, GST_NTP_ERROR_KOD_UNKNOWN,
"Kiss-o'-Death unknown '%s'", code);
}
return NULL;
}
ret = g_new0 (GstNtpPacket, 1);
ret->origin_time =
ntp_timestamp_to_gst_clock_time (GST_READ_UINT32_BE (buffer + 6 * 4),
GST_READ_UINT32_BE (buffer + 7 * 4));
ret->receive_time =
ntp_timestamp_to_gst_clock_time (GST_READ_UINT32_BE (buffer + 8 * 4),
GST_READ_UINT32_BE (buffer + 9 * 4));
ret->transmit_time =
ntp_timestamp_to_gst_clock_time (GST_READ_UINT32_BE (buffer + 10 * 4),
GST_READ_UINT32_BE (buffer + 11 * 4));
/* Wireshark considers everything >= 3 as invalid */
if (poll_interval >= 3)
ret->poll_interval = GST_CLOCK_TIME_NONE;
else if (poll_interval >= 0)
ret->poll_interval = GST_SECOND << poll_interval;
else
ret->poll_interval = GST_SECOND >> (-poll_interval);
} else {
ret = g_new0 (GstNtpPacket, 1);
ret->origin_time = 0;
ret->receive_time = 0;
ret->transmit_time = 0;
ret->poll_interval = 0;
}
return ret;
}
/**
* gst_ntp_packet_free:
* @packet: the #GstNtpPacket
*
* Free @packet.
*/
void
gst_ntp_packet_free (GstNtpPacket * packet)
{
g_free (packet);
}
/**
* gst_ntp_packet_copy:
* @packet: the #GstNtpPacket
*
* Make a copy of @packet.
*
* Returns: a copy of @packet, free with gst_ntp_packet_free().
*/
GstNtpPacket *
gst_ntp_packet_copy (const GstNtpPacket * packet)
{
GstNtpPacket *ret;
ret = g_new0 (GstNtpPacket, 1);
ret->origin_time = packet->origin_time;
ret->receive_time = packet->receive_time;
ret->transmit_time = packet->transmit_time;
return ret;
}
/**
* gst_ntp_packet_serialize:
* @packet: the #GstNtpPacket
*
* Serialized a #GstNtpPacket into a newly-allocated sequence of
* #GST_NTP_PACKET_SIZE bytes, in network byte order. The value returned is
* suitable for passing to write(2) or sendto(2) for communication over the
* network.
*
* MT safe. Caller owns return value (g_free to free).
*
* Returns: A newly allocated sequence of #GST_NTP_PACKET_SIZE bytes.
*/
guint8 *
gst_ntp_packet_serialize (const GstNtpPacket * packet)
{
guint8 *ret;
g_assert (sizeof (GstClockTime) == 8);
ret = g_new0 (guint8, GST_NTP_PACKET_SIZE);
/* Leap Indicator: unknown
* Version: 4
* Mode: Client
*/
ret[0] = (3 << 6) | (4 << 3) | (3 << 0);
/* Stratum: unsynchronized */
ret[1] = 16;
/* Polling interval: invalid */
ret[2] = 3;
/* Precision: 0 */
ret[3] = 0;
/* Root delay: 0 */
GST_WRITE_UINT32_BE (ret + 4, 0);
/* Root disperson: 0 */
GST_WRITE_UINT32_BE (ret + 2 * 4, 0);
/* Reference ID: \0 */
GST_WRITE_UINT32_BE (ret + 3 * 4, 0);
/* Reference Timestamp: 0 */
GST_WRITE_UINT32_BE (ret + 4 * 4, 0);
GST_WRITE_UINT32_BE (ret + 5 * 4, 0);
/* Origin timestamp (local time) */
GST_WRITE_UINT32_BE (ret + 6 * 4,
gst_clock_time_to_ntp_timestamp_seconds (packet->origin_time));
GST_WRITE_UINT32_BE (ret + 7 * 4,
gst_clock_time_to_ntp_timestamp_fraction (packet->origin_time));
/* Receive timestamp (remote time) */
GST_WRITE_UINT32_BE (ret + 8 * 4,
gst_clock_time_to_ntp_timestamp_seconds (packet->receive_time));
GST_WRITE_UINT32_BE (ret + 9 * 4,
gst_clock_time_to_ntp_timestamp_fraction (packet->receive_time));
/* Transmit timestamp (remote time) */
GST_WRITE_UINT32_BE (ret + 10 * 4,
gst_clock_time_to_ntp_timestamp_seconds (packet->transmit_time));
GST_WRITE_UINT32_BE (ret + 11 * 4,
gst_clock_time_to_ntp_timestamp_fraction (packet->transmit_time));
return ret;
}
/**
* gst_ntp_packet_receive:
* @socket: socket to receive the time packet on
* @src_address: (out): address of variable to return sender address
* @error: return address for a #GError, or NULL
*
* Receives a #GstNtpPacket over a socket. Handles interrupted system
* calls, but otherwise returns NULL on error.
*
* Returns: (transfer full): a new #GstNtpPacket, or NULL on error. Free
* with gst_ntp_packet_free() when done.
*/
GstNtpPacket *
gst_ntp_packet_receive (GSocket * socket,
GSocketAddress ** src_address, GError ** error)
{
gchar buffer[GST_NTP_PACKET_SIZE];
GError *err = NULL;
gssize ret;
g_return_val_if_fail (G_IS_SOCKET (socket), FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
while (TRUE) {
ret = g_socket_receive_from (socket, src_address, buffer,
GST_NTP_PACKET_SIZE, NULL, &err);
if (ret < 0) {
if (err->code == G_IO_ERROR_WOULD_BLOCK) {
g_error_free (err);
err = NULL;
continue;
} else {
goto receive_error;
}
} else if (ret < GST_NTP_PACKET_SIZE) {
goto short_packet;
} else {
return gst_ntp_packet_new ((const guint8 *) buffer, error);
}
}
receive_error:
{
GST_DEBUG ("receive error: %s", err->message);
g_propagate_error (error, err);
return NULL;
}
short_packet:
{
GST_DEBUG ("someone sent us a short packet (%" G_GSSIZE_FORMAT " < %d)",
ret, GST_NTP_PACKET_SIZE);
g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_DATA,
"short time packet (%d < %d)", (int) ret, GST_NTP_PACKET_SIZE);
return NULL;
}
}
/**
* gst_ntp_packet_send:
* @packet: the #GstNtpPacket to send
* @socket: socket to send the time packet on
* @dest_address: address to send the time packet to
* @error: return address for a #GError, or NULL
*
* Sends a #GstNtpPacket over a socket.
*
* MT safe.
*
* Returns: TRUE if successful, FALSE in case an error occurred.
*/
gboolean
gst_ntp_packet_send (const GstNtpPacket * packet,
GSocket * socket, GSocketAddress * dest_address, GError ** error)
{
gboolean was_blocking;
guint8 *buffer;
gssize res;
g_return_val_if_fail (packet != NULL, FALSE);
g_return_val_if_fail (G_IS_SOCKET (socket), FALSE);
g_return_val_if_fail (G_IS_SOCKET_ADDRESS (dest_address), FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
was_blocking = g_socket_get_blocking (socket);
if (was_blocking)
g_socket_set_blocking (socket, FALSE);
/* FIXME: avoid pointless alloc/free, serialise into stack-allocated buffer */
buffer = gst_ntp_packet_serialize (packet);
res = g_socket_send_to (socket, dest_address, (const gchar *) buffer,
GST_NTP_PACKET_SIZE, NULL, error);
/* datagram packets should be sent as a whole or not at all */
g_assert (res < 0 || res == GST_NTP_PACKET_SIZE);
g_free (buffer);
if (was_blocking)
g_socket_set_blocking (socket, TRUE);
return (res == GST_NTP_PACKET_SIZE);
}
GQuark
gst_ntp_error_quark (void)
{
static GQuark quark;
/* Thread-safe because GQuark is */
if (!quark)
quark = g_quark_from_static_string ("gst-ntp-error-quark");
return quark;
}