Asterisk - The Open Source Telephony Project  21.4.1
bridge_holding.c
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1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2013, Digium, Inc.
5  *
6  * Jonathan Rose <jrose@digium.com>
7  *
8  * See http://www.asterisk.org for more information about
9  * the Asterisk project. Please do not directly contact
10  * any of the maintainers of this project for assistance;
11  * the project provides a web site, mailing lists and IRC
12  * channels for your use.
13  *
14  * This program is free software, distributed under the terms of
15  * the GNU General Public License Version 2. See the LICENSE file
16  * at the top of the source tree.
17  */
18 
19 /*! \file
20  *
21  * \brief Bridging technology for storing channels in a bridge for
22  * the purpose of holding, parking, queues, and other such
23  * states where a channel may need to be in a bridge but not
24  * actually communicating with anything.
25  *
26  * \author Jonathan Rose <jrose@digium.com>
27  *
28  * \ingroup bridges
29  */
30 
31 /*** MODULEINFO
32  <support_level>core</support_level>
33  ***/
34 
35 #include "asterisk.h"
36 
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <sys/types.h>
41 #include <sys/stat.h>
42 
43 #include "asterisk/module.h"
44 #include "asterisk/channel.h"
45 #include "asterisk/bridge.h"
47 #include "asterisk/frame.h"
48 #include "asterisk/musiconhold.h"
49 #include "asterisk/format_cache.h"
50 
51 enum holding_roles {
52  HOLDING_ROLE_PARTICIPANT,
53  HOLDING_ROLE_ANNOUNCER,
54 };
55 
56 enum idle_modes {
57  IDLE_MODE_NONE,
58  IDLE_MODE_MOH,
59  IDLE_MODE_RINGING,
60  IDLE_MODE_SILENCE,
61  IDLE_MODE_HOLD,
62 };
63 
64 /*! \brief Structure which contains per-channel role information */
66  struct ast_silence_generator *silence_generator;
67  enum holding_roles role;
68  enum idle_modes idle_mode;
69  /*! TRUE if the entertainment is started. */
70  unsigned int entertainment_active:1;
71 };
72 
73 typedef void (*deferred_cb)(struct ast_bridge_channel *bridge_channel);
74 
75 struct deferred_data {
76  /*! Deferred holding technology callback */
77  deferred_cb callback;
78 };
79 
80 static void deferred_action(struct ast_bridge_channel *bridge_channel, const void *payload, size_t payload_size);
81 
82 /*!
83  * \internal
84  * \brief Defer an action to a bridge_channel.
85  * \since 12.0.0
86  *
87  * \param bridge_channel Which channel to operate on.
88  * \param callback action to defer.
89  *
90  * \retval 0 on success.
91  * \retval -1 on error.
92  */
93 static int defer_action(struct ast_bridge_channel *bridge_channel, deferred_cb callback)
94 {
95  struct deferred_data data = { .callback = callback };
96  int res;
97 
98  res = ast_bridge_channel_queue_callback(bridge_channel, 0, deferred_action,
99  &data, sizeof(data));
100  if (res) {
101  ast_log(LOG_WARNING, "Bridge %s: Could not defer action on %s.\n",
102  bridge_channel->bridge->uniqueid, ast_channel_name(bridge_channel->chan));
103  }
104  return res;
105 }
106 
107 /*!
108  * \internal
109  * \brief Setup participant idle mode from channel.
110  * \since 12.0.0
111  *
112  * \param bridge_channel Channel to setup idle mode.
113  */
114 static void participant_idle_mode_setup(struct ast_bridge_channel *bridge_channel)
115 {
116  const char *idle_mode = ast_bridge_channel_get_role_option(bridge_channel, "holding_participant", "idle_mode");
117  struct holding_channel *hc = bridge_channel->tech_pvt;
118 
119  ast_assert(hc != NULL);
120 
121  if (ast_strlen_zero(idle_mode)) {
122  hc->idle_mode = IDLE_MODE_MOH;
123  } else if (!strcmp(idle_mode, "musiconhold")) {
124  hc->idle_mode = IDLE_MODE_MOH;
125  } else if (!strcmp(idle_mode, "ringing")) {
126  hc->idle_mode = IDLE_MODE_RINGING;
127  } else if (!strcmp(idle_mode, "none")) {
128  hc->idle_mode = IDLE_MODE_NONE;
129  } else if (!strcmp(idle_mode, "silence")) {
130  hc->idle_mode = IDLE_MODE_SILENCE;
131  } else if (!strcmp(idle_mode, "hold")) {
132  hc->idle_mode = IDLE_MODE_HOLD;
133  } else {
134  /* Invalid idle mode requested. */
135  ast_debug(1, "channel %s idle mode '%s' doesn't match any defined idle mode\n",
136  ast_channel_name(bridge_channel->chan), idle_mode);
137  ast_assert(0);
138  }
139 }
140 
141 static void participant_entertainment_stop(struct ast_bridge_channel *bridge_channel)
142 {
143  struct holding_channel *hc = bridge_channel->tech_pvt;
144 
145  ast_assert(hc != NULL);
146 
147  if (!hc->entertainment_active) {
148  /* Already stopped */
149  return;
150  }
151  hc->entertainment_active = 0;
152 
153  switch (hc->idle_mode) {
154  case IDLE_MODE_MOH:
155  ast_moh_stop(bridge_channel->chan);
156  break;
157  case IDLE_MODE_RINGING:
158  ast_indicate(bridge_channel->chan, -1);
159  break;
160  case IDLE_MODE_NONE:
161  break;
162  case IDLE_MODE_SILENCE:
163  if (hc->silence_generator) {
164  ast_channel_stop_silence_generator(bridge_channel->chan, hc->silence_generator);
165  hc->silence_generator = NULL;
166  }
167  break;
168  case IDLE_MODE_HOLD:
169  ast_indicate(bridge_channel->chan, AST_CONTROL_UNHOLD);
170  break;
171  }
172 }
173 
174 static void participant_reaction_announcer_join(struct ast_bridge_channel *bridge_channel)
175 {
176  struct ast_channel *chan;
177 
178  chan = bridge_channel->chan;
179  participant_entertainment_stop(bridge_channel);
181  ast_log(LOG_WARNING, "Could not make participant %s compatible.\n", ast_channel_name(chan));
182  }
183 }
184 
185 /* This should only be called on verified holding_participants. */
186 static void participant_entertainment_start(struct ast_bridge_channel *bridge_channel)
187 {
188  struct holding_channel *hc = bridge_channel->tech_pvt;
189  const char *moh_class;
190  size_t moh_length;
191 
192  ast_assert(hc != NULL);
193 
194  if (hc->entertainment_active) {
195  /* Already started */
196  return;
197  }
198  hc->entertainment_active = 1;
199 
200  participant_idle_mode_setup(bridge_channel);
201  switch(hc->idle_mode) {
202  case IDLE_MODE_MOH:
203  moh_class = ast_bridge_channel_get_role_option(bridge_channel, "holding_participant", "moh_class");
204  if (ast_moh_start(bridge_channel->chan, moh_class, NULL)) {
205  ast_log(LOG_WARNING, "Failed to start moh, starting silence generator instead\n");
206  hc->idle_mode = IDLE_MODE_SILENCE;
207  hc->silence_generator = ast_channel_start_silence_generator(bridge_channel->chan);
208  }
209  break;
210  case IDLE_MODE_RINGING:
211  ast_indicate(bridge_channel->chan, AST_CONTROL_RINGING);
212  break;
213  case IDLE_MODE_NONE:
214  break;
215  case IDLE_MODE_SILENCE:
216  hc->silence_generator = ast_channel_start_silence_generator(bridge_channel->chan);
217  break;
218  case IDLE_MODE_HOLD:
219  moh_class = ast_bridge_channel_get_role_option(bridge_channel, "holding_participant", "moh_class");
220  moh_length = moh_class ? strlen(moh_class + 1) : 0;
221  ast_indicate_data(bridge_channel->chan, AST_CONTROL_HOLD, moh_class, moh_length);
222  break;
223  }
224 }
225 
226 static void handle_participant_join(struct ast_bridge_channel *bridge_channel, struct ast_bridge_channel *announcer_channel)
227 {
228  struct ast_channel *us = bridge_channel->chan;
229 
230  /* If the announcer channel isn't present, we need to set up ringing, music on hold, or whatever. */
231  if (!announcer_channel) {
232  defer_action(bridge_channel, participant_entertainment_start);
233  return;
234  }
235 
236  /* We need to get compatible with the announcer. */
238  ast_log(LOG_WARNING, "Could not make participant %s compatible.\n", ast_channel_name(us));
239  }
240 }
241 
242 static int holding_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
243 {
244  struct ast_bridge_channel *other_channel;
245  struct ast_bridge_channel *announcer_channel;
246  struct holding_channel *hc;
247  struct ast_channel *us = bridge_channel->chan; /* The joining channel */
248 
249  ast_assert(bridge_channel->tech_pvt == NULL);
250 
251  if (!(hc = ast_calloc(1, sizeof(*hc)))) {
252  return -1;
253  }
254 
255  bridge_channel->tech_pvt = hc;
256 
257  /* The bridge pvt holds the announcer channel if we have one. */
258  announcer_channel = bridge->tech_pvt;
259 
260  if (ast_bridge_channel_has_role(bridge_channel, "announcer")) {
261  if (announcer_channel) {
262  /* Another announcer already exists. */
263  bridge_channel->tech_pvt = NULL;
264  ast_free(hc);
265  ast_log(LOG_WARNING, "Bridge %s: Channel %s tried to be an announcer. Bridge already has one.\n",
266  bridge->uniqueid, ast_channel_name(bridge_channel->chan));
267  return -1;
268  }
269 
270  bridge->tech_pvt = bridge_channel;
271  hc->role = HOLDING_ROLE_ANNOUNCER;
272 
273  /* The announcer should always be made compatible with signed linear */
275  ast_log(LOG_ERROR, "Could not make announcer %s compatible.\n", ast_channel_name(us));
276  }
277 
278  /* Make everyone listen to the announcer. */
279  AST_LIST_TRAVERSE(&bridge->channels, other_channel, entry) {
280  /* Skip the reaction if we are the channel in question */
281  if (bridge_channel == other_channel) {
282  continue;
283  }
284  defer_action(other_channel, participant_reaction_announcer_join);
285  }
286 
287  return 0;
288  }
289 
290  hc->role = HOLDING_ROLE_PARTICIPANT;
291  handle_participant_join(bridge_channel, announcer_channel);
292  return 0;
293 }
294 
295 static void participant_reaction_announcer_leave(struct ast_bridge_channel *bridge_channel)
296 {
297  ast_bridge_channel_restore_formats(bridge_channel);
298  participant_entertainment_start(bridge_channel);
299 }
300 
301 static void holding_bridge_leave(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
302 {
303  struct ast_bridge_channel *other_channel;
304  struct holding_channel *hc = bridge_channel->tech_pvt;
305 
306  if (!hc) {
307  return;
308  }
309 
310  switch (hc->role) {
311  case HOLDING_ROLE_ANNOUNCER:
312  /* The announcer is leaving */
313  bridge->tech_pvt = NULL;
314 
315  /* Reset the other channels back to moh/ringing. */
316  AST_LIST_TRAVERSE(&bridge->channels, other_channel, entry) {
317  defer_action(other_channel, participant_reaction_announcer_leave);
318  }
319  break;
320  default:
321  /* Nothing needs to react to its departure. */
322  participant_entertainment_stop(bridge_channel);
323  break;
324  }
325  bridge_channel->tech_pvt = NULL;
326  ast_free(hc);
327 }
328 
329 static int holding_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
330 {
331  struct holding_channel *hc = bridge_channel ? bridge_channel->tech_pvt : NULL;
332 
333  /* If there is no tech_pvt, then the channel failed to allocate one when it joined and is borked. Don't listen to him. */
334  if (!hc) {
335  /* "Accept" the frame and discard it. */
336  return 0;
337  }
338 
339  switch (hc->role) {
340  case HOLDING_ROLE_ANNOUNCER:
341  /* Write the frame to all other channels if any. */
342  ast_bridge_queue_everyone_else(bridge, bridge_channel, frame);
343  break;
344  default:
345  /* "Accept" the frame and discard it. */
346  break;
347  }
348 
349  return 0;
350 }
351 
352 static void holding_bridge_suspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
353 {
354  struct holding_channel *hc = bridge_channel->tech_pvt;
355 
356  if (!hc) {
357  return;
358  }
359 
360  switch (hc->role) {
361  case HOLDING_ROLE_PARTICIPANT:
362  participant_entertainment_stop(bridge_channel);
363  break;
364  default:
365  break;
366  }
367 }
368 
369 static void holding_bridge_unsuspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
370 {
371  struct holding_channel *hc = bridge_channel->tech_pvt;
372  struct ast_bridge_channel *announcer_channel = bridge->tech_pvt;
373 
374  if (!hc) {
375  return;
376  }
377 
378  switch (hc->role) {
379  case HOLDING_ROLE_PARTICIPANT:
380  if (announcer_channel) {
381  /* There is an announcer channel in the bridge. */
382  break;
383  }
384  /* We need to restart the entertainment. */
385  participant_entertainment_start(bridge_channel);
386  break;
387  default:
388  break;
389  }
390 }
391 
392 static struct ast_bridge_technology holding_bridge = {
393  .name = "holding_bridge",
394  .capabilities = AST_BRIDGE_CAPABILITY_HOLDING,
395  .preference = AST_BRIDGE_PREFERENCE_BASE_HOLDING,
396  .write = holding_bridge_write,
397  .join = holding_bridge_join,
398  .leave = holding_bridge_leave,
399  .suspend = holding_bridge_suspend,
400  .unsuspend = holding_bridge_unsuspend,
401 };
402 
403 /*!
404  * \internal
405  * \brief Deferred action to start/stop participant entertainment.
406  * \since 12.0.0
407  *
408  * \param bridge_channel Which channel to operate on.
409  * \param payload Data to pass to the callback. (NULL if none).
410  * \param payload_size Size of the payload if payload is non-NULL. A number otherwise.
411  */
412 static void deferred_action(struct ast_bridge_channel *bridge_channel, const void *payload, size_t payload_size)
413 {
414  const struct deferred_data *data = payload;
415 
416  ast_bridge_channel_lock_bridge(bridge_channel);
417  if (bridge_channel->bridge->technology != &holding_bridge
418  || !bridge_channel->tech_pvt) {
419  /* Not valid anymore. */
420  ast_bridge_unlock(bridge_channel->bridge);
421  return;
422  }
423  data->callback(bridge_channel);
424  ast_bridge_unlock(bridge_channel->bridge);
425 }
426 
427 static int unload_module(void)
428 {
429  ast_bridge_technology_unregister(&holding_bridge);
430  return 0;
431 }
432 
433 static int load_module(void)
434 {
435  if (ast_bridge_technology_register(&holding_bridge)) {
436  unload_module();
438  }
440 }
441 
442 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Holding bridge module");
int ast_bridge_channel_has_role(struct ast_bridge_channel *bridge_channel, const char *role_name)
Check to see if a bridge channel inherited a specific role from its channel.
Definition: bridge_roles.c:414
Main Channel structure associated with a channel.
Music on hold handling.
Asterisk main include file. File version handling, generic pbx functions.
const ast_string_field uniqueid
Definition: bridge.h:401
int ast_indicate(struct ast_channel *chan, int condition)
Indicates condition of channel.
Definition: channel.c:4277
int ast_indicate_data(struct ast_channel *chan, int condition, const void *data, size_t datalen)
Indicates condition of channel, with payload.
Definition: channel.c:4653
int ast_bridge_queue_everyone_else(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
Queue the given frame to everyone else.
void ast_moh_stop(struct ast_channel *chan)
Turn off music on hold on a given channel.
Definition: channel.c:7776
struct ast_bridge * bridge
Bridge this channel is participating in.
struct ast_bridge_technology * technology
Definition: bridge.h:355
struct ast_bridge_channel * bridge_channel
General Asterisk PBX channel definitions.
Structure which contains per-channel role information.
int ast_set_read_format(struct ast_channel *chan, struct ast_format *format)
Sets read format on channel chan.
Definition: channel.c:5762
Channel Bridging API.
Asterisk internal frame definitions.
#define ast_debug(level,...)
Log a DEBUG message.
int ast_set_write_format(struct ast_channel *chan, struct ast_format *format)
Sets write format on channel chan.
Definition: channel.c:5803
#define ast_bridge_technology_register(technology)
See __ast_bridge_technology_register()
struct ast_silence_generator * ast_channel_start_silence_generator(struct ast_channel *chan)
Starts a silence generator on the given channel.
Definition: channel.c:8164
Structure that contains information about a bridge.
Definition: bridge.h:349
int ast_bridge_technology_unregister(struct ast_bridge_technology *technology)
Unregister a bridge technology from use.
Definition: bridge.c:263
int ast_moh_start(struct ast_channel *chan, const char *mclass, const char *interpclass)
Turn on music on hold on a given channel.
Definition: channel.c:7766
int ast_bridge_channel_queue_callback(struct ast_bridge_channel *bridge_channel, enum ast_bridge_channel_custom_callback_option flags, ast_bridge_custom_callback_fn callback, const void *payload, size_t payload_size)
Queue a bridge action custom callback frame onto the bridge channel.
struct ast_bridge * bridge
#define AST_LIST_TRAVERSE(head, var, field)
Loops over (traverses) the entries in a list.
Definition: linkedlists.h:491
void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state)
Stops a previously-started silence generator on the given channel.
Definition: channel.c:8210
#define ast_bridge_unlock(bridge)
Unlock the bridge.
Definition: bridge.h:481
deferred_cb callback
#define ast_calloc(num, len)
A wrapper for calloc()
Definition: astmm.h:202
Module has failed to load, may be in an inconsistent state.
Definition: module.h:78
void * tech_pvt
Private information unique to the bridge technology.
struct ast_bridge_channels_list channels
Definition: bridge.h:363
struct ast_channel * chan
Structure that contains information regarding a channel in a bridge.
void ast_bridge_channel_lock_bridge(struct ast_bridge_channel *bridge_channel)
Lock the bridge associated with the bridge channel.
Structure that is the essence of a bridge technology.
Data structure associated with a single frame of data.
void * tech_pvt
Definition: bridge.h:357
Definition: search.h:40
void ast_bridge_channel_restore_formats(struct ast_bridge_channel *bridge_channel)
Restore the formats of a bridge channel's channel to how they were before bridge_channel_internal_joi...
#define ASTERISK_GPL_KEY
The text the key() function should return.
Definition: module.h:46
Bridging API.
struct ast_format * ast_format_slin
Built-in cached signed linear 8kHz format.
Definition: format_cache.c:41
Asterisk module definitions.
const char * ast_bridge_channel_get_role_option(struct ast_bridge_channel *bridge_channel, const char *role_name, const char *option)
Retrieve the value of a requested role option from a bridge channel.
Definition: bridge_roles.c:423
unsigned int entertainment_active
Media Format Cache API.