"smart" channels that update automatically if a channel is masqueraded More...

#include "asterisk.h"
#include "asterisk/linkedlists.h"

Include dependency graph for autochan.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	ast_autochan
Functions
void	ast_autochan_destroy (struct ast_autochan *autochan)
	destroy an ast_autochan structure
void	ast_autochan_new_channel (struct ast_channel old_chan, struct ast_channel new_chan)
	Switch what channel autochans point to.
struct ast_autochan *	ast_autochan_setup (struct ast_channel *chan)
	set up a new ast_autochan structure

Detailed Description

"smart" channels that update automatically if a channel is masqueraded

Author:: Mark Michelson <mmichelson@digium.com>

Definition in file autochan.h.

Function Documentation

void ast_autochan_destroy ( struct ast_autochan * autochan )

destroy an ast_autochan structure

Removes the passed-in autochan from the list of autochans and unrefs the channel that is pointed to. Also frees the autochan struct itself. This function will unref the channel reference which was made in ast_autochan_setup

Parameters:

autochan The autochan that you wish to destroy

Return values:

void

Definition at line 59 of file autochan.c.

References ast_channel_lock, ast_channel_unlock, ast_channel_unref, ast_debug, ast_free, AST_LIST_REMOVE_CURRENT, AST_LIST_TRAVERSE_SAFE_BEGIN, AST_LIST_TRAVERSE_SAFE_END, ast_channel::autochans, ast_autochan::chan, and ast_autochan::list.

Referenced by channel_spy(), common_exec(), launch_monitor_thread(), and mixmonitor_thread().

{
   struct ast_autochan *autochan_iter;

   ast_channel_lock(autochan->chan);
   AST_LIST_TRAVERSE_SAFE_BEGIN(&autochan->chan->autochans, autochan_iter, list) {
      if (autochan_iter == autochan) {
         AST_LIST_REMOVE_CURRENT(list);
         ast_debug(1, "Removed autochan %p from the list, about to free it\n", autochan);
         break;
      }
   }
   AST_LIST_TRAVERSE_SAFE_END;
   ast_channel_unlock(autochan->chan);

   autochan->chan = ast_channel_unref(autochan->chan);

   ast_free(autochan);
}

void ast_autochan_new_channel	(	struct ast_channel *	old_chan,
		struct ast_channel *	new_chan
	)

Switch what channel autochans point to.

Traverses the list of autochans. All autochans which point to old_chan will be updated to point to new_chan instead. Currently this is only called from ast_do_masquerade in channel.c.

Precondition:: Both channels must be locked before calling this function.

Parameters:

old_chan	The channel that autochans may currently point to
new_chan	The channel that we want to point those autochans to now

Return values:

void

Definition at line 79 of file autochan.c.

References ast_channel_ref, ast_channel_unref, ast_debug, AST_LIST_APPEND_LIST, AST_LIST_TRAVERSE, ast_channel::autochans, ast_autochan::chan, ast_autochan::list, and ast_channel::name.

Referenced by ast_do_masquerade().

{
   struct ast_autochan *autochan;

   AST_LIST_APPEND_LIST(&new_chan->autochans, &old_chan->autochans, list);

   AST_LIST_TRAVERSE(&new_chan->autochans, autochan, list) {
      if (autochan->chan == old_chan) {
         autochan->chan = ast_channel_unref(old_chan);
         autochan->chan = ast_channel_ref(new_chan);

         ast_debug(1, "Autochan %p used to hold channel %s (%p) but now holds channel %s (%p)\n",
               autochan, old_chan->name, old_chan, new_chan->name, new_chan);
      }
   }
}

struct ast_autochan* ast_autochan_setup ( struct ast_channel * chan ) [read]

set up a new ast_autochan structure

Just what the $!# is an autochan?

An ast_autochan is a structure which contains an ast_channel. The pointer inside an autochan has the ability to update itself if the channel it points to is masqueraded into a different channel.

This has a great benefit for any application or service which creates a thread outside of the channel's main operating thread which keeps a pointer to said channel. when a masquerade occurs on the channel, the autochan's chan pointer will automatically update to point to the new channel.

Some rules for autochans

1. If you are going to use an autochan, then be sure to always refer to the channel using the chan pointer inside the autochan if possible, since this is the pointer that will be updated during a masquerade.

2. If you are going to save off a pointer to the autochan's chan, then be sure to save off the pointer using ast_channel_ref and to unref the channel when you are finished with the pointer. If you do not do this and a masquerade occurs on the channel, then it is possible that your saved pointer will become invalid.

Allocates and initializes an ast_autochan, sets the autochan's chan pointer to point to the chan parameter, and adds the autochan to the global list of autochans. The newly- created autochan is returned to the caller. This function will cause the refcount of chan to increase by 1.

Parameters:

chan	The channel our new autochan will point to

Note:: autochans must be freed using ast_autochan_destroy

Return values:

NULL	Failure
non-NULL	success

Definition at line 36 of file autochan.c.

References ast_calloc, ast_channel_lock, ast_channel_ref, ast_channel_unlock, ast_debug, AST_LIST_INSERT_TAIL, ast_channel::autochans, ast_autochan::chan, ast_autochan::list, and ast_channel::name.

Referenced by channel_spy(), common_exec(), launch_monitor_thread(), and next_channel().

{
   struct ast_autochan *autochan;

   if (!chan) {
      return NULL;
   }

   if (!(autochan = ast_calloc(1, sizeof(*autochan)))) {
      return NULL;
   }

   autochan->chan = ast_channel_ref(chan);

   ast_channel_lock(autochan->chan);
   AST_LIST_INSERT_TAIL(&autochan->chan->autochans, autochan, list);
   ast_channel_unlock(autochan->chan);

   ast_debug(1, "Created autochan %p to hold channel %s (%p)\n", autochan, chan->name, chan);

   return autochan;
}

Asterisk developer's documentation

Data Structures

Functions

Detailed Description

Function Documentation