agent/candidate.c

   1 /*
   2  * This file is part of the Nice GLib ICE library.
   3  *
   4  * (C) 2006-2009 Collabora Ltd.
   5  *  Contact: Youness Alaoui
   6  * (C) 2006-2009 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  *   Youness Alaoui, Collabora Ltd.
  27  *   Kai Vehmanen, Nokia
  28  *
  29  * Alternatively, the contents of this file may be used under the terms of the
  30  * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
  31  * case the provisions of LGPL are applicable instead of those above. If you
  32  * wish to allow use of your version of this file only under the terms of the
  33  * LGPL and not to allow others to use your version of this file under the
  34  * MPL, indicate your decision by deleting the provisions above and replace
  35  * them with the notice and other provisions required by the LGPL. If you do
  36  * not delete the provisions above, a recipient may use your version of this
  37  * file under either the MPL or the LGPL.
  38  */
  39
  40 /*
  41  * @file candidate.c
  42  * @brief ICE candidate functions
  43  */
  44
  45 #ifdef HAVE_CONFIG_H
  46 # include <config.h>
  47 #else
  48 #define NICEAPI_EXPORT
  49 #endif
  50
  51 #include <string.h>
  52
  53 #include "agent.h"
  54 #include "component.h"
  55
  56 /* (ICE 4.1.1 "Gathering Candidates") ""Every candidate is a transport
  57  * address. It also has a type and a base. Three types are defined and
  58  * gathered by this specification - host candidates, server reflexive
  59  * candidates, and relayed candidates."" (ID-19) */
  60
  61 NICEAPI_EXPORT NiceCandidate *
  62 nice_candidate_new (NiceCandidateType type)
  63 {
  64   NiceCandidate *candidate;
  65
  66   candidate = g_slice_new0 (NiceCandidate);
  67   candidate->type = type;
  68   return candidate;
  69 }
  70
  71
  72 NICEAPI_EXPORT void
  73 nice_candidate_free (NiceCandidate *candidate)
  74 {
  75   /* better way of checking if socket is allocated? */
  76
  77   if (candidate->username)
  78     g_free (candidate->username);
  79
  80   if (candidate->password)
  81     g_free (candidate->password);
  82
  83   g_slice_free (NiceCandidate, candidate);
  84 }
  85
  86
  87 guint32
  88 nice_candidate_jingle_priority (NiceCandidate *candidate)
  89 {
  90   switch (candidate->type)
  91     {
  92     case NICE_CANDIDATE_TYPE_HOST:             return 1000;
  93     case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE: return 900;
  94     case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:   return 900;
  95     case NICE_CANDIDATE_TYPE_RELAYED:          return 500;
  96     }
  97
  98   /* appease GCC */
  99   return 0;
 100 }
 101
 102 guint32
 103 nice_candidate_msn_priority (NiceCandidate *candidate)
 104 {
 105   switch (candidate->type)
 106     {
 107     case NICE_CANDIDATE_TYPE_HOST:             return 830;
 108     case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE: return 550;
 109     case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:   return 550;
 110     case NICE_CANDIDATE_TYPE_RELAYED:          return 450;
 111     }
 112
 113   /* appease GCC */
 114   return 0;
 115 }
 116
 117
 118 /*
 119  * ICE 4.1.2.1. "Recommended Formula" (ID-19):
 120  * returns number between 1 and 0x7effffff
 121  */
 122 guint32
 123 nice_candidate_ice_priority_full (
 124   // must be ∈ (0, 126) (max 2^7 - 2)
 125   guint type_preference,
 126   // must be ∈ (0, 65535) (max 2^16 - 1)
 127   guint local_preference,
 128   // must be ∈ (0, 255) (max 2 ^ 8 - 1)
 129   guint component_id)
 130 {
 131   return (
 132       0x1000000 * type_preference +
 133       0x100 * local_preference +
 134       (0x100 - component_id));
 135 }
 136
 137
 138 guint32
 139 nice_candidate_ice_priority (const NiceCandidate *candidate)
 140 {
 141   guint8 type_preference = 0;
 142
 143   switch (candidate->type)
 144     {
 145     case NICE_CANDIDATE_TYPE_HOST:
 146       type_preference = NICE_CANDIDATE_TYPE_PREF_HOST; break;
 147     case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:
 148       type_preference = NICE_CANDIDATE_TYPE_PREF_PEER_REFLEXIVE; break;
 149     case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE:
 150       type_preference = NICE_CANDIDATE_TYPE_PREF_SERVER_REFLEXIVE; break;
 151     case NICE_CANDIDATE_TYPE_RELAYED:
 152       type_preference = NICE_CANDIDATE_TYPE_PREF_RELAYED; break;
 153     }
 154
 155   /* return _candidate_ice_priority (type_preference, 1, candidate->component_id); */
 156   return nice_candidate_ice_priority_full (type_preference, 1, candidate->component_id);
 157 }
 158
 159 /*
 160  * Calculates the pair priority as specified in ICE
 161  * sect 5.7.2. "Computing Pair Priority and Ordering Pairs" (ID-19).
 162  */
 163 guint64
 164 nice_candidate_pair_priority (guint32 o_prio, guint32 a_prio)
 165 {
 166   guint32 max = o_prio > a_prio ? o_prio : a_prio;
 167   guint32 min = o_prio < a_prio ? o_prio : a_prio;
 168
 169   return ((guint64)1 << 32) * min + 2 * max + (o_prio > a_prio ? 1 : 0);
 170 }
 171
 172 /*
 173  * Copies a candidate
 174  */
 175 NICEAPI_EXPORT NiceCandidate *
 176 nice_candidate_copy (const NiceCandidate *candidate)
 177 {
 178   NiceCandidate *copy = nice_candidate_new (candidate->type);
 179
 180   memcpy (copy, candidate, sizeof(NiceCandidate));
 181
 182   copy->username = g_strdup (copy->username);
 183   copy->password = g_strdup (copy->password);
 184
 185   return copy;
 186 }