Sat Mar 10 01:54:47 2012

Asterisk developer's documentation


bridging_technology.h File Reference

Channel Bridging API. More...

Go to the source code of this file.

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.

00032                            {
00033    /*! Bridge technology should have high precedence over other bridge technologies */
00034    AST_BRIDGE_PREFERENCE_HIGH = 0,
00035    /*! Bridge technology is decent, not the best but should still be considered over low */
00036    AST_BRIDGE_PREFERENCE_MEDIUM,
00037    /*! Bridge technology is low, it should not be considered unless it is absolutely needed */
00038    AST_BRIDGE_PREFERENCE_LOW,
00039 };


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 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.

00060 {
00061    struct ast_bridge_technology *current = NULL;
00062 
00063    /* Perform a sanity check to make sure the bridge technology conforms to our needed requirements */
00064    if (ast_strlen_zero(technology->name) || !technology->capabilities || !technology->write) {
00065       ast_log(LOG_WARNING, "Bridge technology %s failed registration sanity check.\n", technology->name);
00066       return -1;
00067    }
00068 
00069    AST_RWLIST_WRLOCK(&bridge_technologies);
00070 
00071    /* Look for duplicate bridge technology already using this name, or already registered */
00072    AST_RWLIST_TRAVERSE(&bridge_technologies, current, entry) {
00073       if ((!strcasecmp(current->name, technology->name)) || (current == technology)) {
00074          ast_log(LOG_WARNING, "A bridge technology of %s already claims to exist in our world.\n", technology->name);
00075          AST_RWLIST_UNLOCK(&bridge_technologies);
00076          return -1;
00077       }
00078    }
00079 
00080    /* Copy module pointer so reference counting can keep the module from unloading */
00081    technology->mod = module;
00082 
00083    /* Insert our new bridge technology into the list and print out a pretty message */
00084    AST_RWLIST_INSERT_TAIL(&bridge_technologies, technology, entry);
00085 
00086    AST_RWLIST_UNLOCK(&bridge_technologies);
00087 
00088    if (option_verbose > 1) {
00089       ast_verbose(VERBOSE_PREFIX_2 "Registered bridge technology %s\n", technology->name);
00090    }
00091 
00092    return 0;
00093 }

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::features, ast_bridge_channel::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 generic_thread_loop(), and multiplexed_thread_function().

00277 {
00278    /* If no bridge channel has been provided and the actual channel has been provided find it */
00279    if (chan && !bridge_channel) {
00280       bridge_channel = find_bridge_channel(bridge, chan);
00281    }
00282 
00283    /* If a bridge channel with actual channel is present read a frame and handle it */
00284    if (chan && bridge_channel) {
00285       struct ast_frame *frame = (((bridge->features.mute) || (bridge_channel->features && bridge_channel->features->mute)) ? ast_read_noaudio(chan) : ast_read(chan));
00286 
00287       /* This is pretty simple... see if they hung up */
00288       if (!frame || (frame->frametype == AST_FRAME_CONTROL && frame->subclass.integer == AST_CONTROL_HANGUP)) {
00289          /* Signal the thread that is handling the bridged channel that it should be ended */
00290          ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_END);
00291       } else if (frame->frametype == AST_FRAME_CONTROL && bridge_drop_control_frame(frame->subclass.integer)) {
00292          ast_debug(1, "Dropping control frame from bridge channel %p\n", bridge_channel);
00293       } else {
00294          if (frame->frametype == AST_FRAME_DTMF_BEGIN) {
00295             frame = bridge_handle_dtmf(bridge, bridge_channel, frame);
00296          }
00297          /* Simply write the frame out to the bridge technology if it still exists */
00298          if (frame) {
00299             bridge->technology->write(bridge, bridge_channel, frame);
00300          }
00301       }
00302 
00303       if (frame) {
00304          ast_frfree(frame);
00305       }
00306       return;
00307    }
00308 
00309    /* If a file descriptor actually tripped pass it off to the bridge technology */
00310    if (outfd > -1 && bridge->technology->fd) {
00311       bridge->technology->fd(bridge, bridge_channel, outfd);
00312       return;
00313    }
00314 
00315    /* If all else fails just poke the bridge */
00316    if (bridge->technology->poke && bridge_channel) {
00317       bridge->technology->poke(bridge, bridge_channel);
00318       return;
00319    }
00320 
00321    return;
00322 }

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 1230 of file bridging.c.

References ast_bridge_technology::suspended.

01231 {
01232    technology->suspended = 1;
01233    return;
01234 }

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_TRAVERSE_SAFE_END, AST_RWLIST_UNLOCK, AST_RWLIST_WRLOCK, ast_verbose, ast_bridge_technology::name, option_verbose, and VERBOSE_PREFIX_2.

Referenced by unload_module().

00096 {
00097    struct ast_bridge_technology *current = NULL;
00098 
00099    AST_RWLIST_WRLOCK(&bridge_technologies);
00100 
00101    /* Ensure the bridge technology is registered before removing it */
00102    AST_RWLIST_TRAVERSE_SAFE_BEGIN(&bridge_technologies, current, entry) {
00103       if (current == technology) {
00104          AST_RWLIST_REMOVE_CURRENT(entry);
00105          if (option_verbose > 1) {
00106             ast_verbose(VERBOSE_PREFIX_2 "Unregistered bridge technology %s\n", technology->name);
00107          }
00108          break;
00109       }
00110    }
00111    AST_RWLIST_TRAVERSE_SAFE_END;
00112 
00113    AST_RWLIST_UNLOCK(&bridge_technologies);
00114 
00115    return current ? 0 : -1;
00116 }

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 1236 of file bridging.c.

References ast_bridge_technology::suspended.

01237 {
01238    technology->suspended = 0;
01239    return;
01240 }


Generated on Sat Mar 10 01:54:47 2012 for Asterisk - The Open Source Telephony Project by  doxygen 1.4.7