Channel Bridging API. More...

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Data Structures
struct	ast_bridge_technology
	Structure that is the essence of a bridge technology. More...
Defines
#define	ast_bridge_technology_register(technology) __ast_bridge_technology_register(technology, ast_module_info->self)
	See __ast_bridge_technology_register()
Enumerations
enum	ast_bridge_preference { AST_BRIDGE_PREFERENCE_HIGH = 0, AST_BRIDGE_PREFERENCE_MEDIUM, AST_BRIDGE_PREFERENCE_LOW }
	Preference for choosing the bridge technology. More...
Functions
int	__ast_bridge_technology_register (struct ast_bridge_technology technology, struct ast_module mod)
	Register a bridge technology for use.
void	ast_bridge_handle_trip (struct ast_bridge bridge, struct ast_bridge_channel bridge_channel, struct ast_channel *chan, int outfd)
	Feed notification that a frame is waiting on a channel into the bridging core.
void	ast_bridge_notify_talking (struct ast_bridge bridge, struct ast_bridge_channel bridge_channel, int started_talking)
	Lets the bridging indicate when a bridge channel has stopped or started talking.
void	ast_bridge_technology_suspend (struct ast_bridge_technology *technology)
	Suspend a bridge technology from consideration.
int	ast_bridge_technology_unregister (struct ast_bridge_technology *technology)
	Unregister a bridge technology from use.
void	ast_bridge_technology_unsuspend (struct ast_bridge_technology *technology)
	Unsuspend a bridge technology.

Detailed Description

Channel Bridging API.

Author:: Joshua Colp <jcolp@digium.com>

Definition in file bridging_technology.h.

Define Documentation

#define ast_bridge_technology_register ( technology ) __ast_bridge_technology_register(technology, ast_module_info->self)

See __ast_bridge_technology_register()

Definition at line 105 of file bridging_technology.h.

Referenced by load_module().

Enumeration Type Documentation

enum ast_bridge_preference

Preference for choosing the bridge technology.

Enumerator:

AST_BRIDGE_PREFERENCE_HIGH	Bridge technology should have high precedence over other bridge technologies
AST_BRIDGE_PREFERENCE_MEDIUM	Bridge technology is decent, not the best but should still be considered over low
AST_BRIDGE_PREFERENCE_LOW	Bridge technology is low, it should not be considered unless it is absolutely needed

Definition at line 32 of file bridging_technology.h.

                           {
   /*! Bridge technology should have high precedence over other bridge technologies */
   AST_BRIDGE_PREFERENCE_HIGH = 0,
   /*! Bridge technology is decent, not the best but should still be considered over low */
   AST_BRIDGE_PREFERENCE_MEDIUM,
   /*! Bridge technology is low, it should not be considered unless it is absolutely needed */
   AST_BRIDGE_PREFERENCE_LOW,
};

Function Documentation

int __ast_bridge_technology_register	(	struct ast_bridge_technology *	technology,
		struct ast_module *	mod
	)

Register a bridge technology for use.

Parameters:

technology	The bridge technology to register
mod	The module that is registering the bridge technology

Return values:

0	on success
-1	on failure

Example usage:

 ast_bridge_technology_register(&simple_bridge_tech);

This registers a bridge technology declared as the structure simple_bridge_tech with the bridging core and makes it available for use when creating bridges.

Definition at line 66 of file bridging.c.

References ast_log(), AST_RWLIST_INSERT_TAIL, AST_RWLIST_TRAVERSE, AST_RWLIST_UNLOCK, AST_RWLIST_WRLOCK, ast_strlen_zero(), ast_verb, ast_bridge_technology::capabilities, LOG_WARNING, ast_bridge_technology::mod, ast_bridge_technology::name, and ast_bridge_technology::write.

{
   struct ast_bridge_technology *current = NULL;

   /* Perform a sanity check to make sure the bridge technology conforms to our needed requirements */
   if (ast_strlen_zero(technology->name) || !technology->capabilities || !technology->write) {
      ast_log(LOG_WARNING, "Bridge technology %s failed registration sanity check.\n", technology->name);
      return -1;
   }

   AST_RWLIST_WRLOCK(&bridge_technologies);

   /* Look for duplicate bridge technology already using this name, or already registered */
   AST_RWLIST_TRAVERSE(&bridge_technologies, current, entry) {
      if ((!strcasecmp(current->name, technology->name)) || (current == technology)) {
         ast_log(LOG_WARNING, "A bridge technology of %s already claims to exist in our world.\n", technology->name);
         AST_RWLIST_UNLOCK(&bridge_technologies);
         return -1;
      }
   }

   /* Copy module pointer so reference counting can keep the module from unloading */
   technology->mod = module;

   /* Insert our new bridge technology into the list and print out a pretty message */
   AST_RWLIST_INSERT_TAIL(&bridge_technologies, technology, entry);

   AST_RWLIST_UNLOCK(&bridge_technologies);

   ast_verb(2, "Registered bridge technology %s\n", technology->name);

   return 0;
}

void ast_bridge_handle_trip	(	struct ast_bridge *	bridge,
		struct ast_bridge_channel *	bridge_channel,
		struct ast_channel *	chan,
		int	outfd
	)

Feed notification that a frame is waiting on a channel into the bridging core.

Parameters:

bridge	The bridge that the notification should influence
bridge_channel	Bridge channel the notification was received on (if known)
chan	Channel the notification was received on (if known)
outfd	File descriptor that the notification was received on (if known)

Example usage:

 ast_bridge_handle_trip(bridge, NULL, chan, -1);

This tells the bridging core that a frame has been received on the channel pointed to by chan and that it should be read and handled.

Note:: This should only be used by bridging technologies.

Definition at line 285 of file bridging.c.

References ast_bridge_change_state(), AST_BRIDGE_CHANNEL_STATE_END, AST_CONTROL_HANGUP, ast_debug, AST_FRAME_CONTROL, AST_FRAME_DTMF_BEGIN, AST_FRAME_DTMF_END, ast_frfree, ast_read(), ast_read_noaudio(), bridge_drop_control_frame(), bridge_handle_dtmf(), ast_bridge_features::dtmf_passthrough, ast_bridge_technology::fd, ast_bridge_channel::features, ast_bridge::features, find_bridge_channel(), ast_frame::frametype, ast_frame_subclass::integer, ast_bridge_features::mute, ast_bridge_technology::poke, ast_frame::subclass, ast_bridge::technology, and ast_bridge_technology::write.

Referenced by bridge_channel_join_multithreaded(), generic_thread_loop(), and multiplexed_thread_function().

{
   /* If no bridge channel has been provided and the actual channel has been provided find it */
   if (chan && !bridge_channel) {
      bridge_channel = find_bridge_channel(bridge, chan);
   }

   /* If a bridge channel with actual channel is present read a frame and handle it */
   if (chan && bridge_channel) {
      struct ast_frame *frame = (((bridge->features.mute) || (bridge_channel->features && bridge_channel->features->mute)) ? ast_read_noaudio(chan) : ast_read(chan));

      /* This is pretty simple... see if they hung up */
      if (!frame || (frame->frametype == AST_FRAME_CONTROL && frame->subclass.integer == AST_CONTROL_HANGUP)) {
         /* Signal the thread that is handling the bridged channel that it should be ended */
         ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_END);
      } else if (frame->frametype == AST_FRAME_CONTROL && bridge_drop_control_frame(frame->subclass.integer)) {
         ast_debug(1, "Dropping control frame from bridge channel %p\n", bridge_channel);
      } else if (frame->frametype == AST_FRAME_DTMF_BEGIN || frame->frametype == AST_FRAME_DTMF_END) {
         int dtmf_passthrough = bridge_channel->features ?
            bridge_channel->features->dtmf_passthrough :
            bridge->features.dtmf_passthrough;

         if (frame->frametype == AST_FRAME_DTMF_BEGIN) {
            frame = bridge_handle_dtmf(bridge, bridge_channel, frame);
         }

         if (frame && dtmf_passthrough) {
            bridge->technology->write(bridge, bridge_channel, frame);
         }
      } else {
         /* Simply write the frame out to the bridge technology if it still exists */
         bridge->technology->write(bridge, bridge_channel, frame);
      }

      if (frame) {
         ast_frfree(frame);
      }
      return;
   }

   /* If a file descriptor actually tripped pass it off to the bridge technology */
   if (outfd > -1 && bridge->technology->fd) {
      bridge->technology->fd(bridge, bridge_channel, outfd);
      return;
   }

   /* If all else fails just poke the bridge */
   if (bridge->technology->poke && bridge_channel) {
      bridge->technology->poke(bridge, bridge_channel);
      return;
   }

   return;
}

void ast_bridge_notify_talking	(	struct ast_bridge *	bridge,
		struct ast_bridge_channel *	bridge_channel,
		int	started_talking
	)

Lets the bridging indicate when a bridge channel has stopped or started talking.

Note:: All DSP functionality on the bridge has been pushed down to the lowest possible layer, which in this case is the specific bridging technology being used. Since it is necessary for the knowledge of which channels are talking to make its way up to the application, this function has been created to allow the bridging technology to communicate that information with the bridging core.

Parameters:

bridge	The bridge that the channel is a part of.
bridge_channel	The bridge channel that has either started or stopped talking.
started_talking,set	to 1 when this indicates the channel has started talking, set to 0 when this indicates the channel has stopped talking.

Definition at line 276 of file bridging.c.

References ast_bridge_change_state(), AST_BRIDGE_CHANNEL_STATE_START_TALKING, and AST_BRIDGE_CHANNEL_STATE_STOP_TALKING.

Referenced by softmix_bridge_write().

{
   if (started_talking) {
      ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_START_TALKING);
   } else {
      ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_STOP_TALKING);
   }
}

void ast_bridge_technology_suspend ( struct ast_bridge_technology * technology )

Suspend a bridge technology from consideration.

Parameters:

technology The bridge technology to suspend

Example usage:

 ast_bridge_technology_suspend(&simple_bridge_tech);

This suspends the bridge technology simple_bridge_tech from being considered when creating a new bridge. Existing bridges using the bridge technology are not affected.

Definition at line 1350 of file bridging.c.

References ast_bridge_technology::suspended.

{
   technology->suspended = 1;
   return;
}

int ast_bridge_technology_unregister ( struct ast_bridge_technology * technology )

Unregister a bridge technology from use.

Parameters:

technology The bridge technology to unregister

Return values:

0	on success
-1	on failure

Example usage:

 ast_bridge_technology_unregister(&simple_bridge_tech);

This unregisters a bridge technlogy declared as the structure simple_bridge_tech with the bridging core. It will no longer be considered when creating a new bridge.

Definition at line 100 of file bridging.c.

References AST_RWLIST_REMOVE_CURRENT, AST_RWLIST_TRAVERSE_SAFE_BEGIN, AST_RWLIST_TRAVERSE_SAFE_END, AST_RWLIST_UNLOCK, AST_RWLIST_WRLOCK, ast_verb, and ast_bridge_technology::name.

Referenced by unload_module().

{
   struct ast_bridge_technology *current = NULL;

   AST_RWLIST_WRLOCK(&bridge_technologies);

   /* Ensure the bridge technology is registered before removing it */
   AST_RWLIST_TRAVERSE_SAFE_BEGIN(&bridge_technologies, current, entry) {
      if (current == technology) {
         AST_RWLIST_REMOVE_CURRENT(entry);
         ast_verb(2, "Unregistered bridge technology %s\n", technology->name);
         break;
      }
   }
   AST_RWLIST_TRAVERSE_SAFE_END;

   AST_RWLIST_UNLOCK(&bridge_technologies);

   return current ? 0 : -1;
}

void ast_bridge_technology_unsuspend ( struct ast_bridge_technology * technology )

Unsuspend a bridge technology.

Parameters:

technology The bridge technology to unsuspend

Example usage:

 ast_bridge_technology_unsuspend(&simple_bridge_tech);

This makes the bridge technology simple_bridge_tech considered when creating a new bridge again.

Definition at line 1356 of file bridging.c.

References ast_bridge_technology::suspended.

{
   technology->suspended = 0;
   return;
}

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Data Structures

Defines

Enumerations

Functions

Detailed Description

Define Documentation

Enumeration Type Documentation

Function Documentation