chan_bridge.c File Reference

Bridge Interaction Channel. More...

#include "asterisk.h"
#include <fcntl.h>
#include <sys/signal.h>
#include "asterisk/lock.h"
#include "asterisk/channel.h"
#include "asterisk/config.h"
#include "asterisk/module.h"
#include "asterisk/pbx.h"
#include "asterisk/sched.h"
#include "asterisk/io.h"
#include "asterisk/rtp.h"
#include "asterisk/acl.h"
#include "asterisk/callerid.h"
#include "asterisk/file.h"
#include "asterisk/cli.h"
#include "asterisk/app.h"
#include "asterisk/bridging.h"

Include dependency graph for chan_bridge.c:

Go to the source code of this file.

Data Structures
struct	bridge_pvt
Functions
static void	__reg_module (void)
static void	__unreg_module (void)
static struct ast_channel *	bridge_bridgedchannel (struct ast_channel *chan, struct ast_channel *bridge)
	Called when the user of this channel wants to get the actual channel in the bridge.
static int	bridge_call (struct ast_channel *ast, char *dest, int timeout)
	Called when the channel should actually be dialed.
static int	bridge_hangup (struct ast_channel *ast)
	Called when a channel should be hung up.
static void	bridge_queue_hangup (struct bridge_pvt *p, struct ast_channel *us)
	Helper function to not deadlock when queueing the hangup frame.
static struct ast_frame *	bridge_read (struct ast_channel *ast)
	Called when a frame should be read from the channel.
static struct ast_channel *	bridge_request (const char *type, int format, void *data, int *cause)
	Called when we want to place a call somewhere, but not actually call it... yet.
static int	bridge_write (struct ast_channel *ast, struct ast_frame *f)
	Called when a frame should be written out to a channel.
static int	load_module (void)
	Load module into PBX, register channel.
static int	unload_module (void)
	Unload the bridge interaction channel from Asterisk.
Variables
static struct ast_module_info	__mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "Bridge Interaction Channel" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = "0901e4e500243c855563a2d78b0c03e4" , .load = load_module, .unload = unload_module, }
static struct ast_module_info *	ast_module_info = &__mod_info
static struct ast_channel_tech	bridge_tech

---

Detailed Description

Bridge Interaction Channel.

Author:

Joshua Colp <jcolp@digium.com>

Definition in file chan_bridge.c.

---

Function Documentation

static void __reg_module

(

void

)

[static]

Definition at line 246 of file chan_bridge.c.

static void __unreg_module

(

void

)

[static]

Definition at line 246 of file chan_bridge.c.

static struct ast_channel * bridge_bridgedchannel	(	struct ast_channel *	chan,
		struct ast_channel *	bridge
	)			[static, read]

Called when the user of this channel wants to get the actual channel in the bridge.

Definition at line 78 of file chan_bridge.c.

References bridge_pvt::input, bridge_pvt::output, and ast_channel::tech_pvt.

{
   struct bridge_pvt *p = chan->tech_pvt;
   return (chan == p->input) ? p->output : bridge;
}

static int bridge_call	(	struct ast_channel *	ast,
		char *	dest,
		int	timeout
	)			[static]

Called when the channel should actually be dialed.

Definition at line 120 of file chan_bridge.c.

References ast_bridge_impart(), ast_channel::bridge, bridge_pvt::input, bridge_pvt::output, and ast_channel::tech_pvt.

{
   struct bridge_pvt *p = ast->tech_pvt;

   /* If no bridge has been provided on the input channel, bail out */
   if (!ast->bridge) {
      return -1;
   }

   /* Impart the output channel upon the given bridge of the input channel */
   ast_bridge_impart(p->input->bridge, p->output, NULL, NULL);

   return 0;
}

static int bridge_hangup

(

struct ast_channel *

ast

)

[static]

Called when a channel should be hung up.

Definition at line 158 of file chan_bridge.c.

References ast_free, ast_mutex_destroy(), ast_mutex_lock(), ast_mutex_unlock(), bridge_queue_hangup(), bridge_pvt::input, bridge_pvt::lock, bridge_pvt::output, and ast_channel::tech_pvt.

{
   struct bridge_pvt *p = ast->tech_pvt;

   ast_mutex_lock(&p->lock);

   /* Figure out which channel this is... and set it to NULL as it has gone, but also queue up a hangup frame. */
   if (p->input == ast) {
      if (p->output) {
         bridge_queue_hangup(p, ast);
      }
      p->input = NULL;
   } else if (p->output == ast) {
      if (p->input) {
         bridge_queue_hangup(p, ast);
      }
      p->output = NULL;
   }

   /* Deal with the Asterisk portion of it */
   ast->tech_pvt = NULL;

   /* If both sides have been terminated free the structure and be done with things */
   if (!p->input && !p->output) {
      ast_mutex_unlock(&p->lock);
      ast_mutex_destroy(&p->lock);
      ast_free(p);
   } else {
      ast_mutex_unlock(&p->lock);
   }

   return 0;
}

static void bridge_queue_hangup	(	struct bridge_pvt *	p,
		struct ast_channel *	us
	)			[static]

Helper function to not deadlock when queueing the hangup frame.

Definition at line 136 of file chan_bridge.c.

References ast_channel_trylock, ast_channel_unlock, ast_mutex_trylock(), ast_mutex_unlock(), ast_queue_hangup(), CHANNEL_DEADLOCK_AVOIDANCE, bridge_pvt::input, bridge_pvt::lock, and bridge_pvt::output.

Referenced by bridge_hangup().

{
   struct ast_channel *other = (p->input == us ? p->output : p->input);

   while (other && ast_channel_trylock(other)) {
      ast_mutex_unlock(&p->lock);
      do {
         CHANNEL_DEADLOCK_AVOIDANCE(us);
      } while (ast_mutex_trylock(&p->lock));
      other = (p->input == us ? p->output : p->input);
   }

   /* We basically queue the frame up on the other channel if present */
   if (other) {
      ast_queue_hangup(other);
      ast_channel_unlock(other);
   }

   return;
}

static struct ast_frame * bridge_read

(

struct ast_channel *

ast

)

[static, read]

Called when a frame should be read from the channel.

Definition at line 85 of file chan_bridge.c.

References ast_null_frame.

{
   return &ast_null_frame;
}

static struct ast_channel * bridge_request	(	const char *	type,
		int	format,
		void *	data,
		int *	cause
	)			[static, read]

Called when we want to place a call somewhere, but not actually call it... yet.

Definition at line 193 of file chan_bridge.c.

References ast_calloc, ast_channel_alloc, ast_channel_free(), AST_FORMAT_SLINEAR, ast_free, ast_mutex_init(), AST_STATE_UP, bridge_pvt::input, bridge_pvt::lock, ast_channel::nativeformats, bridge_pvt::output, ast_channel::rawreadformat, ast_channel::rawwriteformat, ast_channel::readformat, ast_channel::tech, ast_channel::tech_pvt, and ast_channel::writeformat.

{
   struct bridge_pvt *p = NULL;

   /* Try to allocate memory for our very minimal pvt structure */
   if (!(p = ast_calloc(1, sizeof(*p)))) {
      return NULL;
   }

   /* Try to grab two Asterisk channels to use as input and output channels */
   if (!(p->input = ast_channel_alloc(1, AST_STATE_UP, 0, 0, "", "", "", 0, "Bridge/%p-input", p))) {
      ast_free(p);
      return NULL;
   }
   if (!(p->output = ast_channel_alloc(1, AST_STATE_UP, 0, 0, "", "", "", 0, "Bridge/%p-output", p))) {
      ast_channel_free(p->input);
      ast_free(p);
      return NULL;
   }

   /* Setup the lock on the pvt structure, we will need that */
   ast_mutex_init(&p->lock);

   /* Setup parameters on both new channels */
   p->input->tech = p->output->tech = &bridge_tech;
   p->input->tech_pvt = p->output->tech_pvt = p;
   p->input->nativeformats = p->output->nativeformats = AST_FORMAT_SLINEAR;
   p->input->readformat = p->output->readformat = AST_FORMAT_SLINEAR;
   p->input->rawreadformat = p->output->rawreadformat = AST_FORMAT_SLINEAR;
   p->input->writeformat = p->output->writeformat = AST_FORMAT_SLINEAR;
   p->input->rawwriteformat = p->output->rawwriteformat = AST_FORMAT_SLINEAR;

   return p->input;
}

static int bridge_write	(	struct ast_channel *	ast,
		struct ast_frame *	f
	)			[static]

Called when a frame should be written out to a channel.

Definition at line 91 of file chan_bridge.c.

References ast_channel_trylock, ast_channel_unlock, ast_mutex_lock(), ast_mutex_trylock(), ast_mutex_unlock(), ast_queue_frame(), CHANNEL_DEADLOCK_AVOIDANCE, bridge_pvt::input, bridge_pvt::lock, bridge_pvt::output, and ast_channel::tech_pvt.

{
   struct bridge_pvt *p = ast->tech_pvt;
   struct ast_channel *other;

   ast_mutex_lock(&p->lock);

   other = (p->input == ast ? p->output : p->input);

   while (other && ast_channel_trylock(other)) {
      ast_mutex_unlock(&p->lock);
      do {
         CHANNEL_DEADLOCK_AVOIDANCE(ast);
      } while (ast_mutex_trylock(&p->lock));
      other = (p->input == ast ? p->output : p->input);
   }

   /* We basically queue the frame up on the other channel if present */
   if (other) {
      ast_queue_frame(other, f);
      ast_channel_unlock(other);
   }

   ast_mutex_unlock(&p->lock);

   return 0;
}

static int load_module

(

void

)

[static]

Load module into PBX, register channel.

Definition at line 229 of file chan_bridge.c.

References ast_channel_register(), ast_log(), AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_SUCCESS, and LOG_ERROR.

{
   /* Make sure we can register our channel type */
   if (ast_channel_register(&bridge_tech)) {
      ast_log(LOG_ERROR, "Unable to register channel class 'Bridge'\n");
      return AST_MODULE_LOAD_FAILURE;
   }
   return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module

(

void

)

[static]

Unload the bridge interaction channel from Asterisk.

Definition at line 240 of file chan_bridge.c.

References ast_channel_unregister().

{
   ast_channel_unregister(&bridge_tech);
   return 0;
}

---

Variable Documentation

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "Bridge Interaction Channel" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = "0901e4e500243c855563a2d78b0c03e4" , .load = load_module, .unload = unload_module, } [static]

Definition at line 246 of file chan_bridge.c.

struct ast_module_info* ast_module_info = &__mod_info [static]

Definition at line 246 of file chan_bridge.c.

struct ast_channel_tech bridge_tech [static]

Definition at line 57 of file chan_bridge.c.