dial.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2007, Digium, Inc.
 *
 * Joshua Colp <jcolp@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Dialing API
 *
 * \author Joshua Colp <jcolp@digium.com>
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 380854 $")

#include <sys/time.h>
#include <signal.h>

#include "asterisk/channel.h"
#include "asterisk/utils.h"
#include "asterisk/lock.h"
#include "asterisk/linkedlists.h"
#include "asterisk/dial.h"
#include "asterisk/pbx.h"
#include "asterisk/musiconhold.h"
#include "asterisk/app.h"

/*! \brief Main dialing structure. Contains global options, channels being dialed, and more! */
struct ast_dial {
   int num;                                           /*!< Current number to give to next dialed channel */
   int timeout;                                       /*!< Maximum time allowed for dial attempts */
   int actual_timeout;                                /*!< Actual timeout based on all factors (ie: channels) */
   enum ast_dial_result state;                        /*!< Status of dial */
   void *options[AST_DIAL_OPTION_MAX];                /*!< Global options */
   ast_dial_state_callback state_callback;            /*!< Status callback */
   void *user_data;                                   /*!< Attached user data */
   AST_LIST_HEAD(, ast_dial_channel) channels; /*!< Channels being dialed */
   pthread_t thread;                                  /*!< Thread (if running in async) */
   struct ast_callid *callid;                         /*!< callid pointer (if running in async) */
   ast_mutex_t lock;                                  /*! Lock to protect the thread information above */
};

/*! \brief Dialing channel structure. Contains per-channel dialing options, asterisk channel, and more! */
struct ast_dial_channel {
   int num;          /*!< Unique number for dialed channel */
   int timeout;            /*!< Maximum time allowed for attempt */
   char *tech;          /*!< Technology being dialed */
   char *device;           /*!< Device being dialed */
   void *options[AST_DIAL_OPTION_MAX]; /*!< Channel specific options */
   int cause;           /*!< Cause code in case of failure */
   unsigned int is_running_app:1;      /*!< Is this running an application? */
   struct ast_channel *owner;    /*!< Asterisk channel */
   AST_LIST_ENTRY(ast_dial_channel) list; /*!< Linked list information */
};

/*! \brief Typedef for dial option enable */
typedef void *(*ast_dial_option_cb_enable)(void *data);

/*! \brief Typedef for dial option disable */
typedef int (*ast_dial_option_cb_disable)(void *data);

/*! \brief Structure for 'ANSWER_EXEC' option */
struct answer_exec_struct {
   char app[AST_MAX_APP]; /*!< Application name */
   char *args;            /*!< Application arguments */
};

/*! \brief Enable function for 'ANSWER_EXEC' option */
static void *answer_exec_enable(void *data)
{
   struct answer_exec_struct *answer_exec = NULL;
   char *app = ast_strdupa((char*)data), *args = NULL;

   /* Not giving any data to this option is bad, mmmk? */
   if (ast_strlen_zero(app))
      return NULL;

   /* Create new data structure */
   if (!(answer_exec = ast_calloc(1, sizeof(*answer_exec))))
      return NULL;

   /* Parse out application and arguments */
   if ((args = strchr(app, ','))) {
      *args++ = '\0';
      answer_exec->args = ast_strdup(args);
   }

   /* Copy application name */
   ast_copy_string(answer_exec->app, app, sizeof(answer_exec->app));

   return answer_exec;
}

/*! \brief Disable function for 'ANSWER_EXEC' option */
static int answer_exec_disable(void *data)
{
   struct answer_exec_struct *answer_exec = data;

   /* Make sure we have a value */
   if (!answer_exec)
      return -1;

   /* If arguments are present, free them too */
   if (answer_exec->args)
      ast_free(answer_exec->args);

   /* This is simple - just free the structure */
   ast_free(answer_exec);

   return 0;
}

static void *music_enable(void *data)
{
   return ast_strdup(data);
}

static int music_disable(void *data)
{
   if (!data)
      return -1;

   ast_free(data);

   return 0;
}

/*! \brief Application execution function for 'ANSWER_EXEC' option */
static void answer_exec_run(struct ast_dial *dial, struct ast_dial_channel *dial_channel, char *app, char *args)
{
   struct ast_channel *chan = dial_channel->owner;
   struct ast_app *ast_app = pbx_findapp(app);

   /* If the application was not found, return immediately */
   if (!ast_app)
      return;

   /* All is well... execute the application */
   pbx_exec(chan, ast_app, args);

   /* If another thread is not taking over hang up the channel */
   ast_mutex_lock(&dial->lock);
   if (dial->thread != AST_PTHREADT_STOP) {
      ast_hangup(chan);
      dial_channel->owner = NULL;
   }
   ast_mutex_unlock(&dial->lock);

   return;
}

struct ast_option_types {
   enum ast_dial_option option;
   ast_dial_option_cb_enable enable;
   ast_dial_option_cb_disable disable;
};

/*!
 * \brief Map options to respective handlers (enable/disable).
 *
 * \note This list MUST be perfectly kept in order with enum
 * ast_dial_option, or else madness will happen.
 */
static const struct ast_option_types option_types[] = {
   { AST_DIAL_OPTION_RINGING, NULL, NULL },                                  /*!< Always indicate ringing to caller */
   { AST_DIAL_OPTION_ANSWER_EXEC, answer_exec_enable, answer_exec_disable }, /*!< Execute application upon answer in async mode */
   { AST_DIAL_OPTION_MUSIC, music_enable, music_disable },                   /*!< Play music to the caller instead of ringing */
   { AST_DIAL_OPTION_DISABLE_CALL_FORWARDING, NULL, NULL },                  /*!< Disable call forwarding on channels */
   { AST_DIAL_OPTION_MAX, NULL, NULL },                                      /*!< Terminator of list */
};

/*! \brief Maximum number of channels we can watch at a time */
#define AST_MAX_WATCHERS 256

/*! \brief Macro for finding the option structure to use on a dialed channel */
#define FIND_RELATIVE_OPTION(dial, dial_channel, ast_dial_option) (dial_channel->options[ast_dial_option] ? dial_channel->options[ast_dial_option] : dial->options[ast_dial_option])

/*! \brief Macro that determines whether a channel is the caller or not */
#define IS_CALLER(chan, owner) (chan == owner ? 1 : 0)

/*! \brief New dialing structure
 * \note Create a dialing structure
 * \return Returns a calloc'd ast_dial structure, NULL on failure
 */
struct ast_dial *ast_dial_create(void)
{
   struct ast_dial *dial = NULL;

   /* Allocate new memory for structure */
   if (!(dial = ast_calloc(1, sizeof(*dial))))
      return NULL;

   /* Initialize list of channels */
   AST_LIST_HEAD_INIT(&dial->channels);

   /* Initialize thread to NULL */
   dial->thread = AST_PTHREADT_NULL;

   /* No timeout exists... yet */
   dial->timeout = -1;
   dial->actual_timeout = -1;

   /* Can't forget about the lock */
   ast_mutex_init(&dial->lock);

   return dial;
}

/*! \brief Append a channel
 * \note Appends a channel to a dialing structure
 * \return Returns channel reference number on success, -1 on failure
 */
int ast_dial_append(struct ast_dial *dial, const char *tech, const char *device)
{
   struct ast_dial_channel *channel = NULL;

   /* Make sure we have required arguments */
   if (!dial || !tech || !device)
      return -1;

   /* Allocate new memory for dialed channel structure */
   if (!(channel = ast_calloc(1, sizeof(*channel))))
      return -1;

   /* Record technology and device for when we actually dial */
   channel->tech = ast_strdup(tech);
   channel->device = ast_strdup(device);

   /* Grab reference number from dial structure */
   channel->num = ast_atomic_fetchadd_int(&dial->num, +1);

   /* No timeout exists... yet */
   channel->timeout = -1;

   /* Insert into channels list */
   AST_LIST_INSERT_TAIL(&dial->channels, channel, list);

   return channel->num;
}

/*! \brief Helper function that does the beginning dialing per-appended channel */
static int begin_dial_channel(struct ast_dial_channel *channel, struct ast_channel *chan)
{
   char numsubst[AST_MAX_EXTENSION];
   int res = 1;
   struct ast_format_cap *cap_all_audio = NULL;
   struct ast_format_cap *cap_request;

   /* Copy device string over */
   ast_copy_string(numsubst, channel->device, sizeof(numsubst));

   if (chan) {
      cap_request = ast_channel_nativeformats(chan);
   } else {
      cap_all_audio = ast_format_cap_alloc_nolock();
      ast_format_cap_add_all_by_type(cap_all_audio, AST_FORMAT_TYPE_AUDIO);
      cap_request = cap_all_audio;
   }

   /* If we fail to create our owner channel bail out */
   if (!(channel->owner = ast_request(channel->tech, cap_request, chan, numsubst, &channel->cause))) {
      cap_all_audio = ast_format_cap_destroy(cap_all_audio);
      return -1;
   }
   cap_request = NULL;
   cap_all_audio = ast_format_cap_destroy(cap_all_audio);

   ast_channel_appl_set(channel->owner, "AppDial2");
   ast_channel_data_set(channel->owner, "(Outgoing Line)");
   memset(ast_channel_whentohangup(channel->owner), 0, sizeof(*ast_channel_whentohangup(channel->owner)));

   /* Inherit everything from he who spawned this dial */
   if (chan) {
      ast_channel_inherit_variables(chan, channel->owner);
      ast_channel_datastore_inherit(chan, channel->owner);

      /* Copy over callerid information */
      ast_party_redirecting_copy(ast_channel_redirecting(channel->owner), ast_channel_redirecting(chan));

      ast_channel_dialed(channel->owner)->transit_network_select = ast_channel_dialed(chan)->transit_network_select;

      ast_connected_line_copy_from_caller(ast_channel_connected(channel->owner), ast_channel_caller(chan));

      ast_channel_language_set(channel->owner, ast_channel_language(chan));
      ast_channel_accountcode_set(channel->owner, ast_channel_accountcode(chan));
      if (ast_strlen_zero(ast_channel_musicclass(channel->owner)))
         ast_channel_musicclass_set(channel->owner, ast_channel_musicclass(chan));

      ast_channel_adsicpe_set(channel->owner, ast_channel_adsicpe(chan));
      ast_channel_transfercapability_set(channel->owner, ast_channel_transfercapability(chan));
   }

   /* Attempt to actually call this device */
   if ((res = ast_call(channel->owner, numsubst, 0))) {
      res = 0;
      ast_hangup(channel->owner);
      channel->owner = NULL;
   } else {
      if (chan)
         ast_poll_channel_add(chan, channel->owner);
      res = 1;
      ast_verb(3, "Called %s\n", numsubst);
   }

   return res;
}

/*! \brief Helper function that does the beginning dialing per dial structure */
static int begin_dial(struct ast_dial *dial, struct ast_channel *chan)
{
   struct ast_dial_channel *channel = NULL;
   int success = 0;

   /* Iterate through channel list, requesting and calling each one */
   AST_LIST_LOCK(&dial->channels);
   AST_LIST_TRAVERSE(&dial->channels, channel, list) {
      success += begin_dial_channel(channel, chan);
   }
   AST_LIST_UNLOCK(&dial->channels);

   /* If number of failures matches the number of channels, then this truly failed */
   return success;
}

/*! \brief Helper function to handle channels that have been call forwarded */
static int handle_call_forward(struct ast_dial *dial, struct ast_dial_channel *channel, struct ast_channel *chan)
{
   struct ast_channel *original = channel->owner;
   char *tmp = ast_strdupa(ast_channel_call_forward(channel->owner));
   char *tech = "Local", *device = tmp, *stuff;

   /* If call forwarding is disabled just drop the original channel and don't attempt to dial the new one */
   if (FIND_RELATIVE_OPTION(dial, channel, AST_DIAL_OPTION_DISABLE_CALL_FORWARDING)) {
      ast_hangup(original);
      channel->owner = NULL;
      return 0;
   }

   /* Figure out the new destination */
   if ((stuff = strchr(tmp, '/'))) {
      *stuff++ = '\0';
      tech = tmp;
      device = stuff;
   }

   /* Drop old destination information */
   ast_free(channel->tech);
   ast_free(channel->device);

   /* Update the dial channel with the new destination information */
   channel->tech = ast_strdup(tech);
   channel->device = ast_strdup(device);
   AST_LIST_UNLOCK(&dial->channels);

   /* Finally give it a go... send it out into the world */
   begin_dial_channel(channel, chan);

   /* Drop the original channel */
   ast_hangup(original);

   return 0;
}

/*! \brief Helper function that finds the dialed channel based on owner */
static struct ast_dial_channel *find_relative_dial_channel(struct ast_dial *dial, struct ast_channel *owner)
{
   struct ast_dial_channel *channel = NULL;

   AST_LIST_LOCK(&dial->channels);
   AST_LIST_TRAVERSE(&dial->channels, channel, list) {
      if (channel->owner == owner)
         break;
   }
   AST_LIST_UNLOCK(&dial->channels);

   return channel;
}

static void set_state(struct ast_dial *dial, enum ast_dial_result state)
{
   dial->state = state;

   if (dial->state_callback)
      dial->state_callback(dial);
}

/*! \brief Helper function that handles control frames WITH owner */
static void handle_frame(struct ast_dial *dial, struct ast_dial_channel *channel, struct ast_frame *fr, struct ast_channel *chan)
{
   if (fr->frametype == AST_FRAME_CONTROL) {
      switch (fr->subclass.integer) {
      case AST_CONTROL_ANSWER:
         ast_verb(3, "%s answered %s\n", ast_channel_name(channel->owner), ast_channel_name(chan));
         AST_LIST_LOCK(&dial->channels);
         AST_LIST_REMOVE(&dial->channels, channel, list);
         AST_LIST_INSERT_HEAD(&dial->channels, channel, list);
         AST_LIST_UNLOCK(&dial->channels);
         set_state(dial, AST_DIAL_RESULT_ANSWERED);
         break;
      case AST_CONTROL_BUSY:
         ast_verb(3, "%s is busy\n", ast_channel_name(channel->owner));
         ast_hangup(channel->owner);
         channel->owner = NULL;
         break;
      case AST_CONTROL_CONGESTION:
         ast_verb(3, "%s is circuit-busy\n", ast_channel_name(channel->owner));
         ast_hangup(channel->owner);
         channel->owner = NULL;
         break;
      case AST_CONTROL_INCOMPLETE:
         ast_verb(3, "%s dialed Incomplete extension %s\n", ast_channel_name(channel->owner), ast_channel_exten(channel->owner));
         ast_indicate(chan, AST_CONTROL_INCOMPLETE);
         break;
      case AST_CONTROL_RINGING:
         ast_verb(3, "%s is ringing\n", ast_channel_name(channel->owner));
         if (!dial->options[AST_DIAL_OPTION_MUSIC])
            ast_indicate(chan, AST_CONTROL_RINGING);
         set_state(dial, AST_DIAL_RESULT_RINGING);
         break;
      case AST_CONTROL_PROGRESS:
         ast_verb(3, "%s is making progress, passing it to %s\n", ast_channel_name(channel->owner), ast_channel_name(chan));
         ast_indicate(chan, AST_CONTROL_PROGRESS);
         set_state(dial, AST_DIAL_RESULT_PROGRESS);
         break;
      case AST_CONTROL_VIDUPDATE:
         ast_verb(3, "%s requested a video update, passing it to %s\n", ast_channel_name(channel->owner), ast_channel_name(chan));
         ast_indicate(chan, AST_CONTROL_VIDUPDATE);
         break;
      case AST_CONTROL_SRCUPDATE:
         ast_verb(3, "%s requested a source update, passing it to %s\n", ast_channel_name(channel->owner), ast_channel_name(chan));
         ast_indicate(chan, AST_CONTROL_SRCUPDATE);
         break;
      case AST_CONTROL_CONNECTED_LINE:
         ast_verb(3, "%s connected line has changed, passing it to %s\n", ast_channel_name(channel->owner), ast_channel_name(chan));
         if (ast_channel_connected_line_sub(channel->owner, chan, fr, 1) &&
            ast_channel_connected_line_macro(channel->owner, chan, fr, 1, 1)) {
            ast_indicate_data(chan, AST_CONTROL_CONNECTED_LINE, fr->data.ptr, fr->datalen);
         }
         break;
      case AST_CONTROL_REDIRECTING:
         ast_verb(3, "%s redirecting info has changed, passing it to %s\n", ast_channel_name(channel->owner), ast_channel_name(chan));
         if (ast_channel_redirecting_sub(channel->owner, chan, fr, 1) &&
            ast_channel_redirecting_macro(channel->owner, chan, fr, 1, 1)) {
            ast_indicate_data(chan, AST_CONTROL_REDIRECTING, fr->data.ptr, fr->datalen);
         }
         break;
      case AST_CONTROL_PROCEEDING:
         ast_verb(3, "%s is proceeding, passing it to %s\n", ast_channel_name(channel->owner), ast_channel_name(chan));
         ast_indicate(chan, AST_CONTROL_PROCEEDING);
         set_state(dial, AST_DIAL_RESULT_PROCEEDING);
         break;
      case AST_CONTROL_HOLD:
         ast_verb(3, "Call on %s placed on hold\n", ast_channel_name(chan));
         ast_indicate(chan, AST_CONTROL_HOLD);
         break;
      case AST_CONTROL_UNHOLD:
         ast_verb(3, "Call on %s left from hold\n", ast_channel_name(chan));
         ast_indicate(chan, AST_CONTROL_UNHOLD);
         break;
      case AST_CONTROL_OFFHOOK:
      case AST_CONTROL_FLASH:
         break;
      case AST_CONTROL_PVT_CAUSE_CODE:
         ast_indicate_data(chan, AST_CONTROL_PVT_CAUSE_CODE, fr->data.ptr, fr->datalen);
         break;
      case -1:
         /* Prod the channel */
         ast_indicate(chan, -1);
         break;
      default:
         break;
      }
   }

   return;
}

/*! \brief Helper function that handles control frames WITHOUT owner */
static void handle_frame_ownerless(struct ast_dial *dial, struct ast_dial_channel *channel, struct ast_frame *fr)
{
   /* If we have no owner we can only update the state of the dial structure, so only look at control frames */
   if (fr->frametype != AST_FRAME_CONTROL)
      return;

   switch (fr->subclass.integer) {
   case AST_CONTROL_ANSWER:
      ast_verb(3, "%s answered\n", ast_channel_name(channel->owner));
      AST_LIST_LOCK(&dial->channels);
      AST_LIST_REMOVE(&dial->channels, channel, list);
      AST_LIST_INSERT_HEAD(&dial->channels, channel, list);
      AST_LIST_UNLOCK(&dial->channels);
      set_state(dial, AST_DIAL_RESULT_ANSWERED);
      break;
   case AST_CONTROL_BUSY:
      ast_verb(3, "%s is busy\n", ast_channel_name(channel->owner));
      ast_hangup(channel->owner);
      channel->owner = NULL;
      break;
   case AST_CONTROL_CONGESTION:
      ast_verb(3, "%s is circuit-busy\n", ast_channel_name(channel->owner));
      ast_hangup(channel->owner);
      channel->owner = NULL;
      break;
   case AST_CONTROL_RINGING:
      ast_verb(3, "%s is ringing\n", ast_channel_name(channel->owner));
      set_state(dial, AST_DIAL_RESULT_RINGING);
      break;
   case AST_CONTROL_PROGRESS:
      ast_verb(3, "%s is making progress\n", ast_channel_name(channel->owner));
      set_state(dial, AST_DIAL_RESULT_PROGRESS);
      break;
   case AST_CONTROL_PROCEEDING:
      ast_verb(3, "%s is proceeding\n", ast_channel_name(channel->owner));
      set_state(dial, AST_DIAL_RESULT_PROCEEDING);
      break;
   default:
      break;
   }

   return;
}

/*! \brief Helper function to handle when a timeout occurs on dialing attempt */
static int handle_timeout_trip(struct ast_dial *dial, struct timeval start)
{
   struct ast_dial_channel *channel = NULL;
   int diff = ast_tvdiff_ms(ast_tvnow(), start), lowest_timeout = -1, new_timeout = -1;

   /* If the global dial timeout tripped switch the state to timeout so our channel loop will drop every channel */
   if (diff >= dial->timeout) {
      set_state(dial, AST_DIAL_RESULT_TIMEOUT);
      new_timeout = 0;
   }

   /* Go through dropping out channels that have met their timeout */
   AST_LIST_TRAVERSE(&dial->channels, channel, list) {
      if (dial->state == AST_DIAL_RESULT_TIMEOUT || diff >= channel->timeout) {
         ast_hangup(channel->owner);
         channel->owner = NULL;
      } else if ((lowest_timeout == -1) || (lowest_timeout > channel->timeout)) {
         lowest_timeout = channel->timeout;
      }
   }

   /* Calculate the new timeout using the lowest timeout found */
   if (lowest_timeout >= 0)
      new_timeout = lowest_timeout - diff;

   return new_timeout;
}

/*! \brief Helper function that basically keeps tabs on dialing attempts */
static enum ast_dial_result monitor_dial(struct ast_dial *dial, struct ast_channel *chan)
{
   int timeout = -1;
   struct ast_channel *cs[AST_MAX_WATCHERS], *who = NULL;
   struct ast_dial_channel *channel = NULL;
   struct answer_exec_struct *answer_exec = NULL;
   struct timeval start;

   set_state(dial, AST_DIAL_RESULT_TRYING);

   /* If the "always indicate ringing" option is set, change state to ringing and indicate to the owner if present */
   if (dial->options[AST_DIAL_OPTION_RINGING]) {
      set_state(dial, AST_DIAL_RESULT_RINGING);
      if (chan)
         ast_indicate(chan, AST_CONTROL_RINGING);
   } else if (chan && dial->options[AST_DIAL_OPTION_MUSIC] &&
      !ast_strlen_zero(dial->options[AST_DIAL_OPTION_MUSIC])) {
      char *original_moh = ast_strdupa(ast_channel_musicclass(chan));
      ast_indicate(chan, -1);
      ast_channel_musicclass_set(chan, dial->options[AST_DIAL_OPTION_MUSIC]);
      ast_moh_start(chan, dial->options[AST_DIAL_OPTION_MUSIC], NULL);
      ast_channel_musicclass_set(chan, original_moh);
   }

   /* Record start time for timeout purposes */
   start = ast_tvnow();

   /* We actually figured out the maximum timeout we can do as they were added, so we can directly access the info */
   timeout = dial->actual_timeout;

   /* Go into an infinite loop while we are trying */
   while ((dial->state != AST_DIAL_RESULT_UNANSWERED) && (dial->state != AST_DIAL_RESULT_ANSWERED) && (dial->state != AST_DIAL_RESULT_HANGUP) && (dial->state != AST_DIAL_RESULT_TIMEOUT)) {
      int pos = 0, count = 0;
      struct ast_frame *fr = NULL;

      /* Set up channel structure array */
      pos = count = 0;
      if (chan)
         cs[pos++] = chan;

      /* Add channels we are attempting to dial */
      AST_LIST_LOCK(&dial->channels);
      AST_LIST_TRAVERSE(&dial->channels, channel, list) {
         if (channel->owner) {
            cs[pos++] = channel->owner;
            count++;
         }
      }
      AST_LIST_UNLOCK(&dial->channels);

      /* If we have no outbound channels in progress, switch state to unanswered and stop */
      if (!count) {
         set_state(dial, AST_DIAL_RESULT_UNANSWERED);
         break;
      }

      /* Just to be safe... */
      if (dial->thread == AST_PTHREADT_STOP)
         break;

      /* Wait for frames from channels */
      who = ast_waitfor_n(cs, pos, &timeout);

      /* Check to see if our thread is being cancelled */
      if (dial->thread == AST_PTHREADT_STOP)
         break;

      /* If the timeout no longer exists OR if we got no channel it basically means the timeout was tripped, so handle it */
      if (!timeout || !who) {
         timeout = handle_timeout_trip(dial, start);
         continue;
      }

      /* Find relative dial channel */
      if (!chan || !IS_CALLER(chan, who))
         channel = find_relative_dial_channel(dial, who);

      /* See if this channel has been forwarded elsewhere */
      if (!ast_strlen_zero(ast_channel_call_forward(who))) {
         handle_call_forward(dial, channel, chan);
         continue;
      }

      /* Attempt to read in a frame */
      if (!(fr = ast_read(who))) {
         /* If this is the caller then we switch state to hangup and stop */
         if (chan && IS_CALLER(chan, who)) {
            set_state(dial, AST_DIAL_RESULT_HANGUP);
            break;
         }
         if (chan)
            ast_poll_channel_del(chan, channel->owner);
         ast_hangup(who);
         channel->owner = NULL;
         continue;
      }

      /* Process the frame */
      if (chan)
         handle_frame(dial, channel, fr, chan);
      else
         handle_frame_ownerless(dial, channel, fr);

      /* Free the received frame and start all over */
      ast_frfree(fr);
   }

   /* Do post-processing from loop */
   if (dial->state == AST_DIAL_RESULT_ANSWERED) {
      /* Hangup everything except that which answered */
      AST_LIST_LOCK(&dial->channels);
      AST_LIST_TRAVERSE(&dial->channels, channel, list) {
         if (!channel->owner || channel->owner == who)
            continue;
         if (chan)
            ast_poll_channel_del(chan, channel->owner);
         ast_hangup(channel->owner);
         channel->owner = NULL;
      }
      AST_LIST_UNLOCK(&dial->channels);
      /* If ANSWER_EXEC is enabled as an option, execute application on answered channel */
      if ((channel = find_relative_dial_channel(dial, who)) && (answer_exec = FIND_RELATIVE_OPTION(dial, channel, AST_DIAL_OPTION_ANSWER_EXEC))) {
         channel->is_running_app = 1;
         answer_exec_run(dial, channel, answer_exec->app, answer_exec->args);
         channel->is_running_app = 0;
      }

      if (chan && dial->options[AST_DIAL_OPTION_MUSIC] &&
         !ast_strlen_zero(dial->options[AST_DIAL_OPTION_MUSIC])) {
         ast_moh_stop(chan);
      }
   } else if (dial->state == AST_DIAL_RESULT_HANGUP) {
      /* Hangup everything */
      AST_LIST_LOCK(&dial->channels);
      AST_LIST_TRAVERSE(&dial->channels, channel, list) {
         if (!channel->owner)
            continue;
         if (chan)
            ast_poll_channel_del(chan, channel->owner);
         ast_hangup(channel->owner);
         channel->owner = NULL;
      }
      AST_LIST_UNLOCK(&dial->channels);
   }

   return dial->state;
}

/*! \brief Dial async thread function */
static void *async_dial(void *data)
{
   struct ast_dial *dial = data;
   if (dial->callid) {
      ast_callid_threadassoc_add(dial->callid);
   }

   /* This is really really simple... we basically pass monitor_dial a NULL owner and it changes it's behavior */
   monitor_dial(dial, NULL);

   return NULL;
}

/*! \brief Execute dialing synchronously or asynchronously
 * \note Dials channels in a dial structure.
 * \return Returns dial result code. (TRYING/INVALID/FAILED/ANSWERED/TIMEOUT/UNANSWERED).
 */
enum ast_dial_result ast_dial_run(struct ast_dial *dial, struct ast_channel *chan, int async)
{
   enum ast_dial_result res = AST_DIAL_RESULT_TRYING;

   /* Ensure required arguments are passed */
   if (!dial || (!chan && !async)) {
      ast_debug(1, "invalid #1\n");
      return AST_DIAL_RESULT_INVALID;
   }

   /* If there are no channels to dial we can't very well try to dial them */
   if (AST_LIST_EMPTY(&dial->channels)) {
      ast_debug(1, "invalid #2\n");
      return AST_DIAL_RESULT_INVALID;
   }

   /* Dial each requested channel */
   if (!begin_dial(dial, chan))
      return AST_DIAL_RESULT_FAILED;

   /* If we are running async spawn a thread and send it away... otherwise block here */
   if (async) {
      /* reference be released at dial destruction if it isn't NULL */
      dial->callid = ast_read_threadstorage_callid();
      dial->state = AST_DIAL_RESULT_TRYING;
      /* Try to create a thread */
      if (ast_pthread_create(&dial->thread, NULL, async_dial, dial)) {
         /* Failed to create the thread - hangup all dialed channels and return failed */
         ast_dial_hangup(dial);
         res = AST_DIAL_RESULT_FAILED;
      }
   } else {
      res = monitor_dial(dial, chan);
   }

   return res;
}

/*! \brief Return channel that answered
 * \note Returns the Asterisk channel that answered
 * \param dial Dialing structure
 */
struct ast_channel *ast_dial_answered(struct ast_dial *dial)
{
   if (!dial)
      return NULL;

   return ((dial->state == AST_DIAL_RESULT_ANSWERED) ? AST_LIST_FIRST(&dial->channels)->owner : NULL);
}

/*! \brief Steal the channel that answered
 * \note Returns the Asterisk channel that answered and removes it from the dialing structure
 * \param dial Dialing structure
 */
struct ast_channel *ast_dial_answered_steal(struct ast_dial *dial)
{
   struct ast_channel *chan = NULL;

   if (!dial)
      return NULL;

   if (dial->state == AST_DIAL_RESULT_ANSWERED) {
      chan = AST_LIST_FIRST(&dial->channels)->owner;
      AST_LIST_FIRST(&dial->channels)->owner = NULL;
   }

   return chan;
}

/*! \brief Return state of dial
 * \note Returns the state of the dial attempt
 * \param dial Dialing structure
 */
enum ast_dial_result ast_dial_state(struct ast_dial *dial)
{
   return dial->state;
}

/*! \brief Cancel async thread
 * \note Cancel a running async thread
 * \param dial Dialing structure
 */
enum ast_dial_result ast_dial_join(struct ast_dial *dial)
{
   pthread_t thread;

   /* If the dial structure is not running in async, return failed */
   if (dial->thread == AST_PTHREADT_NULL)
      return AST_DIAL_RESULT_FAILED;

   /* Record thread */
   thread = dial->thread;

   /* Boom, commence locking */
   ast_mutex_lock(&dial->lock);

   /* Stop the thread */
   dial->thread = AST_PTHREADT_STOP;

   /* If the answered channel is running an application we have to soft hangup it, can't just poke the thread */
   AST_LIST_LOCK(&dial->channels);
   if (AST_LIST_FIRST(&dial->channels)->is_running_app) {
      struct ast_channel *chan = AST_LIST_FIRST(&dial->channels)->owner;
      if (chan) {
         ast_channel_lock(chan);
         ast_softhangup(chan, AST_SOFTHANGUP_EXPLICIT);
         ast_channel_unlock(chan);
      }
   } else {
      /* Now we signal it with SIGURG so it will break out of it's waitfor */
      pthread_kill(thread, SIGURG);
   }
   AST_LIST_UNLOCK(&dial->channels);

   /* Yay done with it */
   ast_mutex_unlock(&dial->lock);

   /* Finally wait for the thread to exit */
   pthread_join(thread, NULL);

   /* Yay thread is all gone */
   dial->thread = AST_PTHREADT_NULL;

   return dial->state;
}

/*! \brief Hangup channels
 * \note Hangup all active channels
 * \param dial Dialing structure
 */
void ast_dial_hangup(struct ast_dial *dial)
{
   struct ast_dial_channel *channel = NULL;

   if (!dial)
      return;

   AST_LIST_LOCK(&dial->channels);
   AST_LIST_TRAVERSE(&dial->channels, channel, list) {
      if (channel->owner) {
         ast_hangup(channel->owner);
         channel->owner = NULL;
      }
   }
   AST_LIST_UNLOCK(&dial->channels);

   return;
}

/*! \brief Destroys a dialing structure
 * \note Destroys (free's) the given ast_dial structure
 * \param dial Dialing structure to free
 * \return Returns 0 on success, -1 on failure
 */
int ast_dial_destroy(struct ast_dial *dial)
{
   int i = 0;
   struct ast_dial_channel *channel = NULL;

   if (!dial)
      return -1;

   /* Hangup and deallocate all the dialed channels */
   AST_LIST_LOCK(&dial->channels);
   AST_LIST_TRAVERSE_SAFE_BEGIN(&dial->channels, channel, list) {
      /* Disable any enabled options */
      for (i = 0; i < AST_DIAL_OPTION_MAX; i++) {
         if (!channel->options[i])
            continue;
         if (option_types[i].disable)
            option_types[i].disable(channel->options[i]);
         channel->options[i] = NULL;
      }
      /* Hang up channel if need be */
      if (channel->owner) {
         ast_hangup(channel->owner);
         channel->owner = NULL;
      }
      /* Free structure */
      ast_free(channel->tech);
      ast_free(channel->device);
      AST_LIST_REMOVE_CURRENT(list);
      ast_free(channel);
   }
   AST_LIST_TRAVERSE_SAFE_END;
   AST_LIST_UNLOCK(&dial->channels);

   /* Disable any enabled options globally */
   for (i = 0; i < AST_DIAL_OPTION_MAX; i++) {
      if (!dial->options[i])
         continue;
      if (option_types[i].disable)
         option_types[i].disable(dial->options[i]);
      dial->options[i] = NULL;
   }

   /* Lock be gone! */
   ast_mutex_destroy(&dial->lock);

   /* Get rid of the reference to the ast_callid */
   if (dial->callid) {
      ast_callid_unref(dial->callid);
   }

   /* Free structure */
   ast_free(dial);

   return 0;
}

/*! \brief Enables an option globally
 * \param dial Dial structure to enable option on
 * \param option Option to enable
 * \param data Data to pass to this option (not always needed)
 * \return Returns 0 on success, -1 on failure
 */
int ast_dial_option_global_enable(struct ast_dial *dial, enum ast_dial_option option, void *data)
{
   /* If the option is already enabled, return failure */
   if (dial->options[option])
      return -1;

   /* Execute enable callback if it exists, if not simply make sure the value is set */
   if (option_types[option].enable)
      dial->options[option] = option_types[option].enable(data);
   else
      dial->options[option] = (void*)1;

   return 0;
}

/*! \brief Helper function for finding a channel in a dial structure based on number
 */
static struct ast_dial_channel *find_dial_channel(struct ast_dial *dial, int num)
{
   struct ast_dial_channel *channel = AST_LIST_LAST(&dial->channels);

   /* We can try to predict programmer behavior, the last channel they added is probably the one they wanted to modify */
   if (channel->num == num)
      return channel;

   /* Hrm not at the end... looking through the list it is! */
   AST_LIST_LOCK(&dial->channels);
   AST_LIST_TRAVERSE(&dial->channels, channel, list) {
      if (channel->num == num)
         break;
   }
   AST_LIST_UNLOCK(&dial->channels);

   return channel;
}

/*! \brief Enables an option per channel
 * \param dial Dial structure
 * \param num Channel number to enable option on
 * \param option Option to enable
 * \param data Data to pass to this option (not always needed)
 * \return Returns 0 on success, -1 on failure
 */
int ast_dial_option_enable(struct ast_dial *dial, int num, enum ast_dial_option option, void *data)
{
   struct ast_dial_channel *channel = NULL;

   /* Ensure we have required arguments */
   if (!dial || AST_LIST_EMPTY(&dial->channels))
      return -1;

   if (!(channel = find_dial_channel(dial, num)))
      return -1;

   /* If the option is already enabled, return failure */
   if (channel->options[option])
      return -1;

   /* Execute enable callback if it exists, if not simply make sure the value is set */
   if (option_types[option].enable)
      channel->options[option] = option_types[option].enable(data);
   else
      channel->options[option] = (void*)1;

   return 0;
}

/*! \brief Disables an option globally
 * \param dial Dial structure to disable option on
 * \param option Option to disable
 * \return Returns 0 on success, -1 on failure
 */
int ast_dial_option_global_disable(struct ast_dial *dial, enum ast_dial_option option)
{
   /* If the option is not enabled, return failure */
   if (!dial->options[option]) {
      return -1;
   }

   /* Execute callback of option to disable if it exists */
   if (option_types[option].disable)
      option_types[option].disable(dial->options[option]);

   /* Finally disable option on the structure */
   dial->options[option] = NULL;

   return 0;
}

/*! \brief Disables an option per channel
 * \param dial Dial structure
 * \param num Channel number to disable option on
 * \param option Option to disable
 * \return Returns 0 on success, -1 on failure
 */
int ast_dial_option_disable(struct ast_dial *dial, int num, enum ast_dial_option option)
{
   struct ast_dial_channel *channel = NULL;

   /* Ensure we have required arguments */
   if (!dial || AST_LIST_EMPTY(&dial->channels))
      return -1;

   if (!(channel = find_dial_channel(dial, num)))
      return -1;

   /* If the option is not enabled, return failure */
   if (!channel->options[option])
      return -1;

   /* Execute callback of option to disable it if it exists */
   if (option_types[option].disable)
      option_types[option].disable(channel->options[option]);

   /* Finally disable the option on the structure */
   channel->options[option] = NULL;

   return 0;
}

void ast_dial_set_state_callback(struct ast_dial *dial, ast_dial_state_callback callback)
{
   dial->state_callback = callback;
}

void ast_dial_set_user_data(struct ast_dial *dial, void *user_data)
{
   dial->user_data = user_data;
}

void *ast_dial_get_user_data(struct ast_dial *dial)
{
   return dial->user_data;
}

/*! \brief Set the maximum time (globally) allowed for trying to ring phones
 * \param dial The dial structure to apply the time limit to
 * \param timeout Maximum time allowed
 * \return nothing
 */
void ast_dial_set_global_timeout(struct ast_dial *dial, int timeout)
{
   dial->timeout = timeout;

   if (dial->timeout > 0 && (dial->actual_timeout > dial->timeout || dial->actual_timeout == -1))
      dial->actual_timeout = dial->timeout;

   return;
}

/*! \brief Set the maximum time (per channel) allowed for trying to ring the phone
 * \param dial The dial structure the channel belongs to
 * \param num Channel number to set timeout on
 * \param timeout Maximum time allowed
 * \return nothing
 */
void ast_dial_set_timeout(struct ast_dial *dial, int num, int timeout)
{
   struct ast_dial_channel *channel = NULL;

   if (!(channel = find_dial_channel(dial, num)))
      return;

   channel->timeout = timeout;

   if (channel->timeout > 0 && (dial->actual_timeout > channel->timeout || dial->actual_timeout == -1))
      dial->actual_timeout = channel->timeout;

   return;
}