candidate.c 4.38 KB
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/*
 * This file is part of the Nice GLib ICE library.
 *
 * (C) 2006, 2007 Collabora Ltd.
 *  Contact: Dafydd Harries
 * (C) 2006, 2007 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.
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 *   Kai Vehmanen, Nokia
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 *
 * 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.
 */
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/**
 * @file candidate.c
 * @brief ICE candidate functions
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

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#include "agent.h"
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#include "component.h"
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/* (ICE-13 §4.1.1) Every candidate is a transport address. It also has a type and
 * a base. Three types are defined and gathered by this specification - host
 * candidates, server reflexive candidates, and relayed candidates. */


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NICEAPI_EXPORT NiceCandidate *
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nice_candidate_new (NiceCandidateType type)
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{
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  NiceCandidate *candidate;
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  candidate = g_slice_new0 (NiceCandidate);
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  candidate->type = type;
  return candidate;
}


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NICEAPI_EXPORT void
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nice_candidate_free (NiceCandidate *candidate)
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{
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  /* better way of checking if socket is allocated? */

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  if (candidate->username)
    g_free (candidate->username);

  if (candidate->password)
    g_free (candidate->password);

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  g_slice_free (NiceCandidate, candidate);
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}


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NICEAPI_EXPORT gfloat
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nice_candidate_jingle_priority (NiceCandidate *candidate)
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{
  switch (candidate->type)
    {
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    case NICE_CANDIDATE_TYPE_HOST:             return 1.0;
    case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE: return 0.9;
    case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:   return 0.9;
    case NICE_CANDIDATE_TYPE_RELAYED:          return 0.5;
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    }

  /* appease GCC */
  return 0;
}


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/* ICE-15 §4.1.2.1; returns number between 1 and 0x7effffff */
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G_GNUC_CONST
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NICEAPI_EXPORT guint32
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nice_candidate_ice_priority_full (
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  // must be ∈ (0, 126) (max 2^7 - 2)
  guint type_preference,
  // must be ∈ (0, 65535) (max 2^16 - 1)
  guint local_preference,
  // must be ∈ (1, 255) (max 2 ^ 8 - 1)
  guint component_id)
{
  return (
      0x1000000 * type_preference +
      0x100 * local_preference +
      (0x100 - component_id));
}


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G_GNUC_CONST
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NICEAPI_EXPORT guint32
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nice_candidate_ice_priority (const NiceCandidate *candidate)
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{
  guint8 type_preference = 0;

  switch (candidate->type)
    {
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    case NICE_CANDIDATE_TYPE_HOST:             
      type_preference = NICE_CANDIDATE_TYPE_PREF_HOST; break;
    case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:   
      type_preference = NICE_CANDIDATE_TYPE_PREF_PEER_REFLEXIVE; break;
    case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE:
      type_preference = NICE_CANDIDATE_TYPE_PREF_SERVER_REFLEXIVE; break;
    case NICE_CANDIDATE_TYPE_RELAYED:         
      type_preference = NICE_CANDIDATE_TYPE_PREF_RELAYED; break;
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    }

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  /* return _candidate_ice_priority (type_preference, 1, candidate->component_id); */
  return nice_candidate_ice_priority_full (type_preference, 1, candidate->component_id);
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}

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/** 
 * Calculates the pair priority as specified in ICE -15 spec 5.7.2.
 */
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NICEAPI_EXPORT guint64
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nice_candidate_pair_priority (guint32 o_prio, guint32 a_prio)
{
  guint32 max = o_prio > a_prio ? o_prio : a_prio;
  guint32 min = o_prio < a_prio ? o_prio : a_prio;

  return ((guint64)1 << 32) * min + 2 * max + (o_prio > a_prio ? 1 : 0);
}