agent.c

/*
 * This file is part of the Nice GLib ICE library.
 *
 * (C) 2006-2010 Collabora Ltd.
 *  Contact: Youness Alaoui
 * (C) 2006-2010 Nokia Corporation. All rights reserved.
 *  Contact: Kai Vehmanen
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Nice GLib ICE library.
 *
 * The Initial Developers of the Original Code are Collabora Ltd and Nokia
 * Corporation. All Rights Reserved.
 *
 * Contributors:
 *   Dafydd Harries, Collabora Ltd.
 *   Youness Alaoui, Collabora Ltd.
 *   Kai Vehmanen, Nokia
 *
 * Alternatively, the contents of this file may be used under the terms of the
 * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
 * case the provisions of LGPL are applicable instead of those above. If you
 * wish to allow use of your version of this file only under the terms of the
 * LGPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replace
 * them with the notice and other provisions required by the LGPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the LGPL.
 */


#ifdef HAVE_CONFIG_H
# include <config.h>
#else
#define NICEAPI_EXPORT
#endif

#include <glib.h>

#include <string.h>
#include <errno.h>

#ifndef G_OS_WIN32
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#endif

#include "debug.h"

#include "socket.h"
#include "stun/usages/turn.h"
#include "candidate.h"
#include "component.h"
#include "conncheck.h"
#include "discovery.h"
#include "agent.h"
#include "agent-priv.h"
#include "agent-signals-marshal.h"

#include "stream.h"
#include "interfaces.h"

#include "pseudotcp.h"

/* This is the max size of a UDP packet
 * will it work tcp relaying??
 */
#define MAX_BUFFER_SIZE 65536
#define DEFAULT_STUN_PORT  3478
#define DEFAULT_UPNP_TIMEOUT 200

#define MAX_TCP_MTU 1400 /* Use 1400 because of VPNs and we assume IEE 802.3 */

G_DEFINE_TYPE (NiceAgent, nice_agent, G_TYPE_OBJECT);

enum
{
  PROP_COMPATIBILITY = 1,
  PROP_MAIN_CONTEXT,
  PROP_STUN_SERVER,
  PROP_STUN_SERVER_PORT,
  PROP_CONTROLLING_MODE,
  PROP_FULL_MODE,
  PROP_STUN_PACING_TIMER,
  PROP_MAX_CONNECTIVITY_CHECKS,
  PROP_PROXY_TYPE,
  PROP_PROXY_IP,
  PROP_PROXY_PORT,
  PROP_PROXY_USERNAME,
  PROP_PROXY_PASSWORD,
  PROP_UPNP,
  PROP_UPNP_TIMEOUT,
  PROP_RELIABLE
};


enum
{
  SIGNAL_COMPONENT_STATE_CHANGED,
  SIGNAL_CANDIDATE_GATHERING_DONE,
  SIGNAL_NEW_SELECTED_PAIR,
  SIGNAL_NEW_CANDIDATE,
  SIGNAL_NEW_REMOTE_CANDIDATE,
  SIGNAL_INITIAL_BINDING_REQUEST_RECEIVED,
  SIGNAL_RELIABLE_TRANSPORT_WRITABLE,
  SIGNAL_STREAMS_REMOVED,
  N_SIGNALS,
};

static guint signals[N_SIGNALS];

#if GLIB_CHECK_VERSION(2,31,8)
static GRecMutex agent_mutex;    /* Mutex used for thread-safe lib */
#else
static GStaticRecMutex agent_mutex = G_STATIC_REC_MUTEX_INIT;
#endif

static void priv_attach_stream_component (NiceAgent *agent,
    Stream *stream,
    Component *component);

static void priv_free_upnp (NiceAgent *agent);

#if GLIB_CHECK_VERSION(2,31,8)
void agent_lock (void)
{
  g_rec_mutex_lock (&agent_mutex);
}

void agent_unlock (void)
{
  g_rec_mutex_unlock (&agent_mutex);
}

#else
void agent_lock(void)
{
  g_static_rec_mutex_lock (&agent_mutex);
}

void agent_unlock(void)
{
  g_static_rec_mutex_unlock (&agent_mutex);
}

#endif

StunUsageIceCompatibility
agent_to_ice_compatibility (NiceAgent *agent)
{
  return agent->compatibility == NICE_COMPATIBILITY_GOOGLE ?
      STUN_USAGE_ICE_COMPATIBILITY_GOOGLE :
      agent->compatibility == NICE_COMPATIBILITY_MSN ?
      STUN_USAGE_ICE_COMPATIBILITY_MSN :
      agent->compatibility == NICE_COMPATIBILITY_WLM2009 ?
      STUN_USAGE_ICE_COMPATIBILITY_WLM2009 :
      agent->compatibility == NICE_COMPATIBILITY_OC2007 ?
      STUN_USAGE_ICE_COMPATIBILITY_MSN :
      agent->compatibility == NICE_COMPATIBILITY_OC2007R2 ?
      STUN_USAGE_ICE_COMPATIBILITY_WLM2009 :
      STUN_USAGE_ICE_COMPATIBILITY_RFC5245;
}


StunUsageTurnCompatibility
agent_to_turn_compatibility (NiceAgent *agent)
{
  return agent->compatibility == NICE_COMPATIBILITY_GOOGLE ?
      STUN_USAGE_TURN_COMPATIBILITY_GOOGLE :
      agent->compatibility == NICE_COMPATIBILITY_MSN ?
      STUN_USAGE_TURN_COMPATIBILITY_MSN :
      agent->compatibility == NICE_COMPATIBILITY_WLM2009 ?
      STUN_USAGE_TURN_COMPATIBILITY_MSN :
      agent->compatibility == NICE_COMPATIBILITY_OC2007 ?
      STUN_USAGE_TURN_COMPATIBILITY_OC2007 :
      agent->compatibility == NICE_COMPATIBILITY_OC2007R2 ?
      STUN_USAGE_TURN_COMPATIBILITY_OC2007 :
      STUN_USAGE_TURN_COMPATIBILITY_RFC5766;
}

NiceTurnSocketCompatibility
agent_to_turn_socket_compatibility (NiceAgent *agent)
{
  return agent->compatibility == NICE_COMPATIBILITY_GOOGLE ?
      NICE_TURN_SOCKET_COMPATIBILITY_GOOGLE :
      agent->compatibility == NICE_COMPATIBILITY_MSN ?
      NICE_TURN_SOCKET_COMPATIBILITY_MSN :
      agent->compatibility == NICE_COMPATIBILITY_WLM2009 ?
      NICE_TURN_SOCKET_COMPATIBILITY_MSN :
      agent->compatibility == NICE_COMPATIBILITY_OC2007 ?
      NICE_TURN_SOCKET_COMPATIBILITY_OC2007 :
      agent->compatibility == NICE_COMPATIBILITY_OC2007R2 ?
      NICE_TURN_SOCKET_COMPATIBILITY_OC2007 :
      NICE_TURN_SOCKET_COMPATIBILITY_RFC5766;
}

Stream *agent_find_stream (NiceAgent *agent, guint stream_id)
{
  GSList *i;

  for (i = agent->streams; i; i = i->next)
    {
      Stream *s = i->data;

      if (s->id == stream_id)
        return s;
    }

  return NULL;
}


gboolean
agent_find_component (
  NiceAgent *agent,
  guint stream_id,
  guint component_id,
  Stream **stream,
  Component **component)
{
  Stream *s;
  Component *c;

  s = agent_find_stream (agent, stream_id);

  if (s == NULL)
    return FALSE;

  c = stream_find_component_by_id (s, component_id);

  if (c == NULL)
    return FALSE;

  if (stream)
    *stream = s;

  if (component)
    *component = c;

  return TRUE;
}


static void
nice_agent_dispose (GObject *object);

static void
nice_agent_get_property (
  GObject *object,
  guint property_id,
  GValue *value,
  GParamSpec *pspec);

static void
nice_agent_set_property (
  GObject *object,
  guint property_id,
  const GValue *value,
  GParamSpec *pspec);


static void
nice_agent_class_init (NiceAgentClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->get_property = nice_agent_get_property;
  gobject_class->set_property = nice_agent_set_property;
  gobject_class->dispose = nice_agent_dispose;

  /* install properties */
  /**
   * NiceAgent:main-context:
   *
   * A GLib main context is needed for all timeouts used by libnice.
   * This is a property being set by the nice_agent_new() call.
   */
  g_object_class_install_property (gobject_class, PROP_MAIN_CONTEXT,
      g_param_spec_pointer (
         "main-context",
         "The GMainContext to use for timeouts",
         "The GMainContext to use for timeouts",
         G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));

  /**
   * NiceAgent:compatibility:
   *
   * The Nice agent can work in various compatibility modes depending on
   * what the application/peer needs.
   * <para> See also: #NiceCompatibility</para>
   */
  g_object_class_install_property (gobject_class, PROP_COMPATIBILITY,
      g_param_spec_uint (
         "compatibility",
         "ICE specification compatibility",
         "The compatibility mode for the agent",
         NICE_COMPATIBILITY_RFC5245, NICE_COMPATIBILITY_LAST,
         NICE_COMPATIBILITY_RFC5245,
         G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));

  g_object_class_install_property (gobject_class, PROP_STUN_SERVER,
      g_param_spec_string (
        "stun-server",
        "STUN server IP address",
        "The IP address (not the hostname) of the STUN server to use",
        NULL,
        G_PARAM_READWRITE));

  g_object_class_install_property (gobject_class, PROP_STUN_SERVER_PORT,
      g_param_spec_uint (
        "stun-server-port",
        "STUN server port",
        "Port of the STUN server used to gather server-reflexive candidates",
        1, 65536,
	1, /* not a construct property, ignored */
        G_PARAM_READWRITE));

  g_object_class_install_property (gobject_class, PROP_CONTROLLING_MODE,
      g_param_spec_boolean (
        "controlling-mode",
        "ICE controlling mode",
        "Whether the agent is in controlling mode",
	FALSE, /* not a construct property, ignored */
        G_PARAM_READWRITE));

   g_object_class_install_property (gobject_class, PROP_FULL_MODE,
      g_param_spec_boolean (
        "full-mode",
        "ICE full mode",
        "Whether agent runs in ICE full mode",
	TRUE, /* use full mode by default */
        G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));

  g_object_class_install_property (gobject_class, PROP_STUN_PACING_TIMER,
      g_param_spec_uint (
        "stun-pacing-timer",
        "STUN pacing timer",
        "Timer 'Ta' (msecs) used in the IETF ICE specification for pacing "
        "candidate gathering and sending of connectivity checks",
        1, 0xffffffff,
	NICE_AGENT_TIMER_TA_DEFAULT,
        G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));

  /* note: according to spec recommendation in sect 5.7.3 (ID-19) */
  g_object_class_install_property (gobject_class, PROP_MAX_CONNECTIVITY_CHECKS,
      g_param_spec_uint (
        "max-connectivity-checks",
        "Maximum number of connectivity checks",
        "Upper limit for the total number of connectivity checks performed",
        0, 0xffffffff,
	0, /* default set in init */
        G_PARAM_READWRITE));

  /**
   * NiceAgent:proxy-ip:
   *
   * The proxy server IP used to bypass a proxy firewall
   *
   * Since: 0.0.4
   */
  g_object_class_install_property (gobject_class, PROP_PROXY_IP,
      g_param_spec_string (
        "proxy-ip",
        "Proxy server IP",
        "The proxy server IP used to bypass a proxy firewall",
        NULL,
        G_PARAM_READWRITE));

  /**
   * NiceAgent:proxy-port:
   *
   * The proxy server port used to bypass a proxy firewall
   *
   * Since: 0.0.4
   */
  g_object_class_install_property (gobject_class, PROP_PROXY_PORT,
      g_param_spec_uint (
        "proxy-port",
        "Proxy server port",
        "The Proxy server port used to bypass a proxy firewall",
        1, 65536,
	1,
        G_PARAM_READWRITE));

  /**
   * NiceAgent:proxy-type:
   *
   * The type of proxy set in the proxy-ip property
   *
   * Since: 0.0.4
   */
  g_object_class_install_property (gobject_class, PROP_PROXY_TYPE,
      g_param_spec_uint (
         "proxy-type",
         "Type of proxy to use",
         "The type of proxy set in the proxy-ip property",
         NICE_PROXY_TYPE_NONE, NICE_PROXY_TYPE_LAST,
         NICE_PROXY_TYPE_NONE,
         G_PARAM_READWRITE));

  /**
   * NiceAgent:proxy-username:
   *
   * The username used to authenticate with the proxy
   *
   * Since: 0.0.4
   */
  g_object_class_install_property (gobject_class, PROP_PROXY_USERNAME,
      g_param_spec_string (
        "proxy-username",
        "Proxy server username",
        "The username used to authenticate with the proxy",
        NULL,
        G_PARAM_READWRITE));

  /**
   * NiceAgent:proxy-password:
   *
   * The password used to authenticate with the proxy
   *
   * Since: 0.0.4
   */
  g_object_class_install_property (gobject_class, PROP_PROXY_PASSWORD,
      g_param_spec_string (
        "proxy-password",
        "Proxy server password",
        "The password used to authenticate with the proxy",
        NULL,
        G_PARAM_READWRITE));

  /**
   * NiceAgent:upnp:
   *
   * Whether the agent should use UPnP to open a port in the router and
   * get the external IP
   *
   * Since: 0.0.7
   */
   g_object_class_install_property (gobject_class, PROP_UPNP,
      g_param_spec_boolean (
        "upnp",
#ifdef HAVE_GUPNP
        "Use UPnP",
        "Whether the agent should use UPnP to open a port in the router and "
        "get the external IP",
#else
        "Use UPnP (disabled in build)",
        "Does nothing because libnice was not built with UPnP support",
#endif
	TRUE, /* enable UPnP by default */
        G_PARAM_READWRITE| G_PARAM_CONSTRUCT));

  /**
   * NiceAgent:upnp-timeout:
   *
   * The maximum amount of time to wait for UPnP discovery to finish before
   * signaling the #NiceAgent::candidate-gathering-done signal
   *
   * Since: 0.0.7
   */
  g_object_class_install_property (gobject_class, PROP_UPNP_TIMEOUT,
      g_param_spec_uint (
        "upnp-timeout",
#ifdef HAVE_GUPNP
        "Timeout for UPnP discovery",
        "The maximum amount of time to wait for UPnP discovery to finish before "
        "signaling the candidate-gathering-done signal",
#else
        "Timeout for UPnP discovery (disabled in build)",
        "Does nothing because libnice was not built with UPnP support",
#endif
        100, 60000,
	DEFAULT_UPNP_TIMEOUT,
        G_PARAM_READWRITE | G_PARAM_CONSTRUCT));

  /**
   * NiceAgent:reliable:
   *
   * Whether the agent should use PseudoTcp to ensure a reliable transport
   * of messages
   *
   * Since: 0.0.11
   */
   g_object_class_install_property (gobject_class, PROP_RELIABLE,
      g_param_spec_boolean (
        "reliable",
        "reliable mode",
        "Whether the agent should use PseudoTcp to ensure a reliable transport"
        "of messages",
	FALSE,
        G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));

  /* install signals */

  /**
   * NiceAgent::component-state-changed
   * @agent: The #NiceAgent object
   * @stream_id: The ID of the stream
   * @component_id: The ID of the component
   * @state: The #NiceComponentState of the component
   *
   * This signal is fired whenever a component's state changes
   */
  signals[SIGNAL_COMPONENT_STATE_CHANGED] =
      g_signal_new (
          "component-state-changed",
          G_OBJECT_CLASS_TYPE (klass),
          G_SIGNAL_RUN_LAST,
          0,
          NULL,
          NULL,
          agent_marshal_VOID__UINT_UINT_UINT,
          G_TYPE_NONE,
          3,
          G_TYPE_UINT, G_TYPE_UINT, G_TYPE_UINT,
          G_TYPE_INVALID);

  /**
   * NiceAgent::candidate-gathering-done:
   * @agent: The #NiceAgent object
   * @stream_id: The ID of the stream
   *
   * This signal is fired whenever a stream has finished gathering its
   * candidates after a call to nice_agent_gather_candidates()
   */
  signals[SIGNAL_CANDIDATE_GATHERING_DONE] =
      g_signal_new (
          "candidate-gathering-done",
          G_OBJECT_CLASS_TYPE (klass),
          G_SIGNAL_RUN_LAST,
          0,
          NULL,
          NULL,
          agent_marshal_VOID__UINT,
          G_TYPE_NONE,
          1,
          G_TYPE_UINT, G_TYPE_INVALID);

  /**
   * NiceAgent::new-selected-pair
   * @agent: The #NiceAgent object
   * @stream_id: The ID of the stream
   * @component_id: The ID of the component
   * @lfoundation: The local foundation of the selected candidate pair
   * @rfoundation: The remote foundation of the selected candidate pair
   *
   * This signal is fired once a candidate pair is selected for data transfer for
   * a stream's component
   */
  signals[SIGNAL_NEW_SELECTED_PAIR] =
      g_signal_new (
          "new-selected-pair",
          G_OBJECT_CLASS_TYPE (klass),
          G_SIGNAL_RUN_LAST,
          0,
          NULL,
          NULL,
          agent_marshal_VOID__UINT_UINT_STRING_STRING,
          G_TYPE_NONE,
          4,
          G_TYPE_UINT, G_TYPE_UINT, G_TYPE_STRING, G_TYPE_STRING,
          G_TYPE_INVALID);

  /**
   * NiceAgent::new-candidate
   * @agent: The #NiceAgent object
   * @stream_id: The ID of the stream
   * @component_id: The ID of the component
   * @foundation: The foundation of the new candidate
   *
   * This signal is fired when the agent discovers a new candidate
   * <para> See also: #NiceAgent::candidate-gathering-done </para>
   */
  signals[SIGNAL_NEW_CANDIDATE] =
      g_signal_new (
          "new-candidate",
          G_OBJECT_CLASS_TYPE (klass),
          G_SIGNAL_RUN_LAST,
          0,
          NULL,
          NULL,
          agent_marshal_VOID__UINT_UINT_STRING,
          G_TYPE_NONE,
          3,
          G_TYPE_UINT, G_TYPE_UINT, G_TYPE_STRING,
          G_TYPE_INVALID);

  /**
   * NiceAgent::new-remote-candidate
   * @agent: The #NiceAgent object
   * @stream_id: The ID of the stream
   * @component_id: The ID of the component
   * @foundation: The foundation of the new candidate
   *
   * This signal is fired when the agent discovers a new remote candidate.
   * This can happen with peer reflexive candidates.
   */
  signals[SIGNAL_NEW_REMOTE_CANDIDATE] =
      g_signal_new (
          "new-remote-candidate",
          G_OBJECT_CLASS_TYPE (klass),
          G_SIGNAL_RUN_LAST,
          0,
          NULL,
          NULL,
          agent_marshal_VOID__UINT_UINT_STRING,
          G_TYPE_NONE,
          3,
          G_TYPE_UINT, G_TYPE_UINT, G_TYPE_STRING,
          G_TYPE_INVALID);

  /**
   * NiceAgent::initial-binding-request-received
   * @agent: The #NiceAgent object
   * @stream_id: The ID of the stream
   *
   * This signal is fired when we received our first binding request from
   * the peer.
   */
  signals[SIGNAL_INITIAL_BINDING_REQUEST_RECEIVED] =
      g_signal_new (
          "initial-binding-request-received",
          G_OBJECT_CLASS_TYPE (klass),
          G_SIGNAL_RUN_LAST,
          0,
          NULL,
          NULL,
          agent_marshal_VOID__UINT,
          G_TYPE_NONE,
          1,
          G_TYPE_UINT,
          G_TYPE_INVALID);

  /**
   * NiceAgent::reliable-transport-writable
   * @agent: The #NiceAgent object
   * @stream_id: The ID of the stream
   * @component_id: The ID of the component
   *
   * This signal is fired on the reliable #NiceAgent when the underlying reliable
   * transport becomes writable.
   * This signal is only emitted when the nice_agent_send() function returns less
   * bytes than requested to send (or -1) and once when the connection
   * is established.
   *
   * Since: 0.0.11
   */
  signals[SIGNAL_RELIABLE_TRANSPORT_WRITABLE] =
      g_signal_new (
          "reliable-transport-writable",
          G_OBJECT_CLASS_TYPE (klass),
          G_SIGNAL_RUN_LAST,
          0,
          NULL,
          NULL,
          agent_marshal_VOID__UINT_UINT,
          G_TYPE_NONE,
          2,
          G_TYPE_UINT, G_TYPE_UINT,
          G_TYPE_INVALID);

  /**
   * NiceAgent::streams-removed
   * @agent: The #NiceAgent object
   * @stream_ids: (array zero-terminated=1) (element-type uint): An array of
   * unsigned integer stream IDs, ending with a 0 ID
   *
   * This signal is fired whenever one or more streams are removed from the
   * @agent.
   *
   * Since: 0.1.5
   */
  signals[SIGNAL_STREAMS_REMOVED] =
      g_signal_new (
          "streams-removed",
          G_OBJECT_CLASS_TYPE (klass),
          G_SIGNAL_RUN_LAST,
          0,
          NULL,
          NULL,
          g_cclosure_marshal_VOID__POINTER,
          G_TYPE_NONE,
          1,
          G_TYPE_POINTER,
          G_TYPE_INVALID);

  /* Init debug options depending on env variables */
  nice_debug_init ();
}

static void priv_generate_tie_breaker (NiceAgent *agent) 
{
  nice_rng_generate_bytes (agent->rng, 8, (gchar*)&agent->tie_breaker);
}

static void
nice_agent_init (NiceAgent *agent)
{
  agent->next_candidate_id = 1;
  agent->next_stream_id = 1;

  /* set defaults; not construct params, so set here */
  agent->stun_server_port = DEFAULT_STUN_PORT;
  agent->controlling_mode = TRUE;
  agent->max_conn_checks = NICE_AGENT_MAX_CONNECTIVITY_CHECKS_DEFAULT;

  agent->discovery_list = NULL;
  agent->discovery_unsched_items = 0;
  agent->discovery_timer_source = NULL;
  agent->conncheck_timer_source = NULL;
  agent->keepalive_timer_source = NULL;
  agent->refresh_list = NULL;
  agent->media_after_tick = FALSE;
  agent->software_attribute = NULL;

  agent->compatibility = NICE_COMPATIBILITY_RFC5245;
  agent->reliable = FALSE;

  stun_agent_init (&agent->stun_agent, STUN_ALL_KNOWN_ATTRIBUTES,
      STUN_COMPATIBILITY_RFC5389,
      STUN_AGENT_USAGE_SHORT_TERM_CREDENTIALS |
      STUN_AGENT_USAGE_USE_FINGERPRINT);

  agent->rng = nice_rng_new ();
  priv_generate_tie_breaker (agent);
}


NICEAPI_EXPORT NiceAgent *
nice_agent_new (GMainContext *ctx, NiceCompatibility compat)
{
  NiceAgent *agent = g_object_new (NICE_TYPE_AGENT,
      "compatibility", compat,
      "main-context", ctx,
      "reliable", FALSE,
      NULL);

  return agent;
}


NICEAPI_EXPORT NiceAgent *
nice_agent_new_reliable (GMainContext *ctx, NiceCompatibility compat)
{
  NiceAgent *agent = g_object_new (NICE_TYPE_AGENT,
      "compatibility", compat,
      "main-context", ctx,
      "reliable", TRUE,
      NULL);

  return agent;
}


static void
nice_agent_get_property (
  GObject *object,
  guint property_id,
  GValue *value,
  GParamSpec *pspec)
{
  NiceAgent *agent = NICE_AGENT (object);

  agent_lock();

  switch (property_id)
    {
    case PROP_MAIN_CONTEXT:
      g_value_set_pointer (value, agent->main_context);
      break;

    case PROP_COMPATIBILITY:
      g_value_set_uint (value, agent->compatibility);
      break;

    case PROP_STUN_SERVER:
      g_value_set_string (value, agent->stun_server_ip);
      break;

    case PROP_STUN_SERVER_PORT:
      g_value_set_uint (value, agent->stun_server_port);
      break;

    case PROP_CONTROLLING_MODE:
      g_value_set_boolean (value, agent->controlling_mode);
      break;

    case PROP_FULL_MODE:
      g_value_set_boolean (value, agent->full_mode);
      break;

    case PROP_STUN_PACING_TIMER:
      g_value_set_uint (value, agent->timer_ta);
      break;

    case PROP_MAX_CONNECTIVITY_CHECKS:
      g_value_set_uint (value, agent->max_conn_checks);
      /* XXX: should we prune the list of already existing checks? */
      break;

    case PROP_PROXY_IP:
      g_value_set_string (value, agent->proxy_ip);
      break;

    case PROP_PROXY_PORT:
      g_value_set_uint (value, agent->proxy_port);
      break;

    case PROP_PROXY_TYPE:
      g_value_set_uint (value, agent->proxy_type);
      break;

    case PROP_PROXY_USERNAME:
      g_value_set_string (value, agent->proxy_username);
      break;

    case PROP_PROXY_PASSWORD:
      g_value_set_string (value, agent->proxy_password);
      break;

    case PROP_UPNP:
#ifdef HAVE_GUPNP
      g_value_set_boolean (value, agent->upnp_enabled);
#else
      g_value_set_boolean (value, FALSE);
#endif
      break;

    case PROP_UPNP_TIMEOUT:
#ifdef HAVE_GUPNP
      g_value_set_uint (value, agent->upnp_timeout);
#else
      g_value_set_uint (value, DEFAULT_UPNP_TIMEOUT);
#endif
      break;

    case PROP_RELIABLE:
      g_value_set_boolean (value, agent->reliable);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
    }

  agent_unlock();
}


static void
nice_agent_set_property (
  GObject *object,
  guint property_id,
  const GValue *value,
  GParamSpec *pspec)
{
  NiceAgent *agent = NICE_AGENT (object);

  agent_lock();

  switch (property_id)
    {
    case PROP_MAIN_CONTEXT:
      agent->main_context = g_value_get_pointer (value);
      if (agent->main_context != NULL)
        g_main_context_ref (agent->main_context);
      break;

    case PROP_COMPATIBILITY:
      agent->compatibility = g_value_get_uint (value);
      if (agent->compatibility == NICE_COMPATIBILITY_GOOGLE) {
        stun_agent_init (&agent->stun_agent, STUN_ALL_KNOWN_ATTRIBUTES,
            STUN_COMPATIBILITY_RFC3489,
            STUN_AGENT_USAGE_SHORT_TERM_CREDENTIALS |
            STUN_AGENT_USAGE_IGNORE_CREDENTIALS);
      } else if (agent->compatibility == NICE_COMPATIBILITY_MSN) {
        stun_agent_init (&agent->stun_agent, STUN_ALL_KNOWN_ATTRIBUTES,
            STUN_COMPATIBILITY_RFC3489,
            STUN_AGENT_USAGE_SHORT_TERM_CREDENTIALS |
            STUN_AGENT_USAGE_FORCE_VALIDATER);
      } else if (agent->compatibility == NICE_COMPATIBILITY_WLM2009) {
        stun_agent_init (&agent->stun_agent, STUN_ALL_KNOWN_ATTRIBUTES,
            STUN_COMPATIBILITY_WLM2009,
            STUN_AGENT_USAGE_SHORT_TERM_CREDENTIALS |
            STUN_AGENT_USAGE_USE_FINGERPRINT);
      } else if (agent->compatibility == NICE_COMPATIBILITY_OC2007) {
        stun_agent_init (&agent->stun_agent, STUN_ALL_KNOWN_ATTRIBUTES,
            STUN_COMPATIBILITY_RFC3489,
            STUN_AGENT_USAGE_SHORT_TERM_CREDENTIALS |
            STUN_AGENT_USAGE_FORCE_VALIDATER |
            STUN_AGENT_USAGE_NO_ALIGNED_ATTRIBUTES);
      } else if (agent->compatibility == NICE_COMPATIBILITY_OC2007R2) {
        stun_agent_init (&agent->stun_agent, STUN_ALL_KNOWN_ATTRIBUTES,
            STUN_COMPATIBILITY_WLM2009,
            STUN_AGENT_USAGE_SHORT_TERM_CREDENTIALS |
            STUN_AGENT_USAGE_USE_FINGERPRINT |
            STUN_AGENT_USAGE_NO_ALIGNED_ATTRIBUTES);
      } else {
        stun_agent_init (&agent->stun_agent, STUN_ALL_KNOWN_ATTRIBUTES,
            STUN_COMPATIBILITY_RFC5389,
            STUN_AGENT_USAGE_SHORT_TERM_CREDENTIALS |
            STUN_AGENT_USAGE_USE_FINGERPRINT);
      }
      stun_agent_set_software (&agent->stun_agent, agent->software_attribute);

      break;

    case PROP_STUN_SERVER:
      g_free (agent->stun_server_ip);
      agent->stun_server_ip = g_value_dup_string (value);
      break;

    case PROP_STUN_SERVER_PORT:
      agent->stun_server_port = g_value_get_uint (value);
      break;

    case PROP_CONTROLLING_MODE:
      agent->controlling_mode = g_value_get_boolean (value);
      break;

    case PROP_FULL_MODE:
      agent->full_mode = g_value_get_boolean (value);
      break;

    case PROP_STUN_PACING_TIMER:
      agent->timer_ta = g_value_get_uint (value);
      break;

    case PROP_MAX_CONNECTIVITY_CHECKS:
      agent->max_conn_checks = g_value_get_uint (value);
      break;

    case PROP_PROXY_IP:
      g_free (agent->proxy_ip);
      agent->proxy_ip = g_value_dup_string (value);
      break;

    case PROP_PROXY_PORT:
      agent->proxy_port = g_value_get_uint (value);
      break;

    case PROP_PROXY_TYPE:
      agent->proxy_type = g_value_get_uint (value);
      break;

    case PROP_PROXY_USERNAME:
      g_free (agent->proxy_username);
      agent->proxy_username = g_value_dup_string (value);
      break;

    case PROP_PROXY_PASSWORD:
      g_free (agent->proxy_password);
      agent->proxy_password = g_value_dup_string (value);
      break;

    case PROP_UPNP_TIMEOUT:
#ifdef HAVE_GUPNP
      agent->upnp_timeout = g_value_get_uint (value);
#endif
      break;

    case PROP_UPNP:
#ifdef HAVE_GUPNP
      agent->upnp_enabled = g_value_get_boolean (value);
#endif
      break;

    case PROP_RELIABLE:
      agent->reliable = g_value_get_boolean (value);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
    }

  agent_unlock();

}


static void priv_destroy_component_tcp (Component *component)
{
    if (component->tcp_clock) {
      g_source_destroy (component->tcp_clock);
      g_source_unref (component->tcp_clock);
      component->tcp_clock = NULL;
    }
    if (component->tcp) {
      pseudo_tcp_socket_close (component->tcp, TRUE);
      g_object_unref (component->tcp);
      component->tcp = NULL;
    }
    if (component->tcp_data != NULL) {
      g_slice_free (TcpUserData, component->tcp_data);
      component->tcp_data = NULL;
    }
}

static void priv_pseudo_tcp_error (NiceAgent *agent, Stream *stream,
    Component *component)
{
  if (component->tcp) {
    agent_signal_component_state_change (agent, stream->id,
        component->id, NICE_COMPONENT_STATE_FAILED);
    component_detach_socket_sources (component);
  }
  priv_destroy_component_tcp (component);
}

static void
adjust_tcp_clock (NiceAgent *agent, Stream *stream, Component *component);


static void
pseudo_tcp_socket_opened (PseudoTcpSocket *sock, gpointer user_data)
{
  TcpUserData *data = (TcpUserData *)user_data;
  NiceAgent *agent = data->agent;
  Component *component = data->component;
  Stream *stream = data->stream;

  nice_debug ("Agent %p: s%d:%d pseudo Tcp socket Opened", data->agent,
      stream->id, component->id);
  g_signal_emit (agent, signals[SIGNAL_RELIABLE_TRANSPORT_WRITABLE], 0,
      stream->id, component->id);
}

static void
pseudo_tcp_socket_readable (PseudoTcpSocket *sock, gpointer user_data)
{
  TcpUserData *data = (TcpUserData *)user_data;
  NiceAgent *agent = data->agent;
  Component *component = data->component;
  Stream *stream = data->stream;
  gchar buf[MAX_BUFFER_SIZE];
  gint len;

  nice_debug ("Agent %p: s%d:%d pseudo Tcp socket readable", agent,
      stream->id, component->id);

  component->tcp_readable = TRUE;

  g_object_add_weak_pointer (G_OBJECT (sock), (gpointer *)&sock);
  g_object_add_weak_pointer (G_OBJECT (agent), (gpointer *)&agent);

  do {
    if (component->g_source_io_cb)
      len = pseudo_tcp_socket_recv (sock, buf, sizeof(buf));
    else
      len = 0;

    if (len > 0) {
      gpointer data = component->data;
      gint sid = stream->id;
      gint cid = component->id;
      NiceAgentRecvFunc callback = component->g_source_io_cb;
      /* Unlock the agent before calling the callback */
      agent_unlock();
      callback (agent, sid, cid, len, buf, data);
      agent_lock();
      if (sock == NULL) {
        nice_debug ("PseudoTCP socket got destroyed in readable callback!");
        break;
      }
    } else if (len < 0 &&
        pseudo_tcp_socket_get_error (sock) != EWOULDBLOCK) {
      /* Signal error */
      priv_pseudo_tcp_error (agent, stream, component);
    } else if (len < 0 &&
        pseudo_tcp_socket_get_error (sock) == EWOULDBLOCK){
      component->tcp_readable = FALSE;
    }
  } while (len > 0);

  if (agent) {
    adjust_tcp_clock (agent, stream, component);
    g_object_remove_weak_pointer (G_OBJECT (agent), (gpointer *)&agent);
  } else {
    nice_debug ("Not calling adjust_tcp_clock.. agent got destroyed!");
  }
  if (sock)
    g_object_remove_weak_pointer (G_OBJECT (sock), (gpointer *)&sock);
}

static void
pseudo_tcp_socket_writable (PseudoTcpSocket *sock, gpointer user_data)
{
  TcpUserData *data = (TcpUserData *)user_data;
  NiceAgent *agent = data->agent;
  Component *component = data->component;
  Stream *stream = data->stream;

  nice_debug ("Agent %p: s%d:%d pseudo Tcp socket writable", data->agent,
      data->stream->id, data->component->id);
  g_signal_emit (agent, signals[SIGNAL_RELIABLE_TRANSPORT_WRITABLE], 0,
      stream->id, component->id);
}

static void
pseudo_tcp_socket_closed (PseudoTcpSocket *sock, guint32 err,
    gpointer user_data)
{
  TcpUserData *data = (TcpUserData *)user_data;
  NiceAgent *agent = data->agent;
  Component *component = data->component;
  Stream *stream = data->stream;

  nice_debug ("Agent %p: s%d:%d pseudo Tcp socket closed",  agent,
      stream->id, component->id);
  priv_pseudo_tcp_error (agent, stream, component);
}


static PseudoTcpWriteResult
pseudo_tcp_socket_write_packet (PseudoTcpSocket *socket,
    const gchar *buffer, guint32 len, gpointer user_data)
{
  TcpUserData *data = (TcpUserData *)user_data;
  Component *component = data->component;

  if (component->selected_pair.local != NULL) {
    NiceSocket *sock;
    NiceAddress *addr;

#ifndef NDEBUG
    gchar tmpbuf[INET6_ADDRSTRLEN];
    nice_address_to_string (&component->selected_pair.remote->addr, tmpbuf);

    nice_debug ("Agent %p : s%d:%d: sending %d bytes to [%s]:%d", data->agent,
        data->stream->id, component->id, len, tmpbuf,
        nice_address_get_port (&component->selected_pair.remote->addr));
#endif

    sock = component->selected_pair.local->sockptr;
    addr = &component->selected_pair.remote->addr;
    if (nice_socket_send (sock, addr, len, buffer)) {
      return WR_SUCCESS;
    }
  }

  return WR_FAIL;
}


static gboolean
notify_pseudo_tcp_socket_clock (gpointer user_data)
{
  TcpUserData *data = (TcpUserData *)user_data;
  Component *component = data->component;
  Stream *stream = data->stream;
  NiceAgent *agent = data->agent;

  agent_lock();

  if (g_source_is_destroyed (g_main_current_source ())) {
    nice_debug ("Source was destroyed. "
        "Avoided race condition in notify_pseudo_tcp_socket_clock");
    agent_unlock ();
    return FALSE;
  }
  if (component->tcp_clock) {
    g_source_destroy (component->tcp_clock);
    g_source_unref (component->tcp_clock);
    component->tcp_clock = NULL;
  }

  pseudo_tcp_socket_notify_clock (component->tcp);
  adjust_tcp_clock (agent, stream, component);

  agent_unlock();

  return FALSE;
}

static void
adjust_tcp_clock (NiceAgent *agent, Stream *stream, Component *component)
{
  long timeout = 0;
  if (component->tcp) {
    if (pseudo_tcp_socket_get_next_clock (component->tcp, &timeout)) {
      if (component->tcp_clock) {
        g_source_destroy (component->tcp_clock);
        g_source_unref (component->tcp_clock);
        component->tcp_clock = NULL;
      }
      component->tcp_clock = agent_timeout_add_with_context (agent,
          timeout, notify_pseudo_tcp_socket_clock, component->tcp_data);
    } else {
      nice_debug ("Agent %p: component %d pseudo tcp socket should be destroyed",
          agent, component->id);
      priv_pseudo_tcp_error (agent, stream, component);
    }
  }
}


void agent_gathering_done (NiceAgent *agent)
{

  GSList *i, *j, *k, *l, *m;

  for (i = agent->streams; i; i = i->next) {
    Stream *stream = i->data;
    for (j = stream->components; j; j = j->next) {
      Component *component = j->data;

      for (k = component->local_candidates; k; k = k->next) {
        NiceCandidate *local_candidate = k->data;
	{
	  gchar tmpbuf[INET6_ADDRSTRLEN];
	  nice_address_to_string (&local_candidate->addr, tmpbuf);
          nice_debug ("Agent %p: gathered local candidate : [%s]:%u"
              " for s%d/c%d. U/P '%s'/'%s'", agent,
              tmpbuf, nice_address_get_port (&local_candidate->addr),
              local_candidate->stream_id, local_candidate->component_id,
              local_candidate->username, local_candidate->password);
	}
        for (l = component->remote_candidates; l; l = l->next) {
          NiceCandidate *remote_candidate = l->data;

          for (m = stream->conncheck_list; m; m = m->next) {
            CandidateCheckPair *p = m->data;

            if (p->local == local_candidate && p->remote == remote_candidate)
              break;
          }
          if (m == NULL) {
            conn_check_add_for_candidate (agent, stream->id, component, remote_candidate);
          }
        }
      }
    }
  }

#ifdef HAVE_GUPNP
  if (agent->discovery_timer_source == NULL &&
      agent->upnp_timer_source == NULL) {
    agent_signal_gathering_done (agent);
  }
#else
  if (agent->discovery_timer_source == NULL)
    agent_signal_gathering_done (agent);
#endif
}

void agent_signal_gathering_done (NiceAgent *agent)
{
  GSList *i;

  for (i = agent->streams; i; i = i->next) {
    Stream *stream = i->data;
    if (stream->gathering) {
      stream->gathering = FALSE;