Mon Sep 20 2010 00:26:23

Asterisk developer's documentation

Data Structures | Defines | Enumerations | Functions

bridging_technology.h File Reference

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_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 104 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
module 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 59 of file bridging.c.

References ast_log(), AST_RWLIST_INSERT_TAIL, AST_RWLIST_TRAVERSE, AST_RWLIST_UNLOCK, AST_RWLIST_WRLOCK, ast_strlen_zero(), ast_verbose(), ast_bridge_technology::capabilities, LOG_WARNING, ast_bridge_technology::mod, ast_bridge_technology::name, option_verbose, VERBOSE_PREFIX_2, 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);

   if (option_verbose > 1) {
      ast_verbose(VERBOSE_PREFIX_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 276 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_frfree, ast_read(), ast_read_noaudio(), bridge_drop_control_frame(), bridge_handle_dtmf(), ast_bridge_technology::fd, ast_bridge_channel::features, ast_bridge::features, find_bridge_channel(), ast_frame::frametype, 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 == 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)) {
         ast_debug(1, "Dropping control frame from bridge channel %p\n", bridge_channel);
      } else {
         if (frame->frametype == AST_FRAME_DTMF_BEGIN) {
            frame = bridge_handle_dtmf(bridge, bridge_channel, frame);
         }
         /* Simply write the frame out to the bridge technology if it still exists */
         if (frame) {
            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_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 1223 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 95 of file bridging.c.

References AST_RWLIST_REMOVE_CURRENT, AST_RWLIST_TRAVERSE_SAFE_BEGIN, AST_RWLIST_UNLOCK, AST_RWLIST_WRLOCK, ast_verbose(), ast_bridge_technology::name, option_verbose, and VERBOSE_PREFIX_2.

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);
         if (option_verbose > 1) {
            ast_verbose(VERBOSE_PREFIX_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 1229 of file bridging.c.

References ast_bridge_technology::suspended.

{
   technology->suspended = 0;
   return;
}

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