agent/candidate.c

   1 /*
   2  * This file is part of the Nice GLib ICE library.
   3  *
   4  * (C) 2006, 2007 Collabora Ltd.
   5  *  Contact: Dafydd Harries
   6  * (C) 2006, 2007 Nokia Corporation. All rights reserved.
   7  *  Contact: Kai Vehmanen
   8  *
   9  * The contents of this file are subject to the Mozilla Public License Version
  10  * 1.1 (the "License"); you may not use this file except in compliance with
  11  * the License. You may obtain a copy of the License at
  12  * http://www.mozilla.org/MPL/
  13  *
  14  * Software distributed under the License is distributed on an "AS IS" basis,
  15  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  16  * for the specific language governing rights and limitations under the
  17  * License.
  18  *
  19  * The Original Code is the Nice GLib ICE library.
  20  *
  21  * The Initial Developers of the Original Code are Collabora Ltd and Nokia
  22  * Corporation. All Rights Reserved.
  23  *
  24  * Contributors:
  25  *   Dafydd Harries, Collabora Ltd.
  26  *   Kai Vehmanen, Nokia
  27  *
  28  * Alternatively, the contents of this file may be used under the terms of the
  29  * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
  30  * case the provisions of LGPL are applicable instead of those above. If you
  31  * wish to allow use of your version of this file only under the terms of the
  32  * LGPL and not to allow others to use your version of this file under the
  33  * MPL, indicate your decision by deleting the provisions above and replace
  34  * them with the notice and other provisions required by the LGPL. If you do
  35  * not delete the provisions above, a recipient may use your version of this
  36  * file under either the MPL or the LGPL.
  37  */
  38
  39 /*
  40  * @file candidate.c
  41  * @brief ICE candidate functions
  42  */
  43
  44 #ifdef HAVE_CONFIG_H
  45 # include <config.h>
  46 #else
  47 #define NICEAPI_EXPORT
  48 #endif
  49
  50 #include <string.h>
  51
  52 #include "agent.h"
  53 #include "component.h"
  54
  55 /* (ICE 4.1.1 "Gathering Candidates") ""Every candidate is a transport
  56  * address. It also has a type and a base. Three types are defined and
  57  * gathered by this specification - host candidates, server reflexive
  58  * candidates, and relayed candidates."" (ID-19) */
  59
  60 NICEAPI_EXPORT NiceCandidate *
  61 nice_candidate_new (NiceCandidateType type)
  62 {
  63   NiceCandidate *candidate;
  64
  65   candidate = g_slice_new0 (NiceCandidate);
  66   candidate->type = type;
  67   return candidate;
  68 }
  69
  70
  71 NICEAPI_EXPORT void
  72 nice_candidate_free (NiceCandidate *candidate)
  73 {
  74   /* better way of checking if socket is allocated? */
  75
  76   if (candidate->username)
  77     g_free (candidate->username);
  78
  79   if (candidate->password)
  80     g_free (candidate->password);
  81
  82   g_slice_free (NiceCandidate, candidate);
  83 }
  84
  85
  86 guint32
  87 nice_candidate_jingle_priority (NiceCandidate *candidate)
  88 {
  89   switch (candidate->type)
  90     {
  91     case NICE_CANDIDATE_TYPE_HOST:             return 1000;
  92     case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE: return 900;
  93     case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:   return 900;
  94     case NICE_CANDIDATE_TYPE_RELAYED:          return 500;
  95     }
  96
  97   /* appease GCC */
  98   return 0;
  99 }
 100
 101 guint32
 102 nice_candidate_msn_priority (NiceCandidate *candidate)
 103 {
 104   switch (candidate->type)
 105     {
 106     case NICE_CANDIDATE_TYPE_HOST:             return 830;
 107     case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE: return 550;
 108     case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:   return 550;
 109     case NICE_CANDIDATE_TYPE_RELAYED:          return 450;
 110     }
 111
 112   /* appease GCC */
 113   return 0;
 114 }
 115
 116
 117 /*
 118  * ICE 4.1.2.1. "Recommended Formula" (ID-19):
 119  * returns number between 1 and 0x7effffff
 120  */
 121 guint32
 122 nice_candidate_ice_priority_full (
 123   // must be ∈ (0, 126) (max 2^7 - 2)
 124   guint type_preference,
 125   // must be ∈ (0, 65535) (max 2^16 - 1)
 126   guint local_preference,
 127   // must be ∈ (0, 255) (max 2 ^ 8 - 1)
 128   guint component_id)
 129 {
 130   return (
 131       0x1000000 * type_preference +
 132       0x100 * local_preference +
 133       (0x100 - component_id));
 134 }
 135
 136
 137 guint32
 138 nice_candidate_ice_priority (const NiceCandidate *candidate)
 139 {
 140   guint8 type_preference = 0;
 141
 142   switch (candidate->type)
 143     {
 144     case NICE_CANDIDATE_TYPE_HOST:
 145       type_preference = NICE_CANDIDATE_TYPE_PREF_HOST; break;
 146     case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:
 147       type_preference = NICE_CANDIDATE_TYPE_PREF_PEER_REFLEXIVE; break;
 148     case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE:
 149       type_preference = NICE_CANDIDATE_TYPE_PREF_SERVER_REFLEXIVE; break;
 150     case NICE_CANDIDATE_TYPE_RELAYED:
 151       type_preference = NICE_CANDIDATE_TYPE_PREF_RELAYED; break;
 152     }
 153
 154   /* return _candidate_ice_priority (type_preference, 1, candidate->component_id); */
 155   return nice_candidate_ice_priority_full (type_preference, 1, candidate->component_id);
 156 }
 157
 158 /*
 159  * Calculates the pair priority as specified in ICE
 160  * sect 5.7.2. "Computing Pair Priority and Ordering Pairs" (ID-19).
 161  */
 162 guint64
 163 nice_candidate_pair_priority (guint32 o_prio, guint32 a_prio)
 164 {
 165   guint32 max = o_prio > a_prio ? o_prio : a_prio;
 166   guint32 min = o_prio < a_prio ? o_prio : a_prio;
 167
 168   return ((guint64)1 << 32) * min + 2 * max + (o_prio > a_prio ? 1 : 0);
 169 }
 170
 171 /*
 172  * Copies a candidate
 173  */
 174 NICEAPI_EXPORT NiceCandidate *
 175 nice_candidate_copy (const NiceCandidate *candidate)
 176 {
 177   NiceCandidate *copy = nice_candidate_new (candidate->type);
 178
 179   memcpy (copy, candidate, sizeof(NiceCandidate));
 180
 181   copy->username = g_strdup (copy->username);
 182   copy->password = g_strdup (copy->password);
 183
 184   return copy;
 185 }