features.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2012, Digium, Inc.
 * Copyright (C) 2012, Russell Bryant
 *
 * Mark Spencer <[email protected]>
 *
 * 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 Routines implementing call features as call pickup, parking and transfer
 *
 * \author Mark Spencer <[email protected]>
 */

/*! \li \ref features.c uses the configuration file \ref features.conf
 * \addtogroup configuration_file Configuration Files
 */

/*!
 * \page features.conf features.conf
 * \verbinclude features.conf.sample
 */

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

#include "asterisk.h"

#include "asterisk/_private.h"
#include "features_config.h"

#include <pthread.h>
#include <signal.h>
#include <sys/time.h>
#include <signal.h>
#include <netinet/in.h>

#include "asterisk/lock.h"
#include "asterisk/file.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/causes.h"
#include "asterisk/module.h"
#include "asterisk/translate.h"
#include "asterisk/app.h"
#include "asterisk/say.h"
#include "asterisk/features.h"
#include "asterisk/musiconhold.h"
#include "asterisk/config.h"
#include "asterisk/cli.h"
#include "asterisk/manager.h"
#include "asterisk/utils.h"
#include "asterisk/devicestate.h"
#include "asterisk/audiohook.h"
#include "asterisk/global_datastores.h"
#include "asterisk/astobj2.h"
#include "asterisk/test.h"
#include "asterisk/bridge.h"
#include "asterisk/bridge_features.h"
#include "asterisk/bridge_basic.h"
#include "asterisk/bridge_after.h"
#include "asterisk/stasis.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/features_config.h"
#include "asterisk/max_forwards.h"
#include "asterisk/stream.h"

/*** DOCUMENTATION
   <application name="Bridge" language="en_US">
      <synopsis>
         Bridge two channels.
      </synopsis>
      <syntax>
         <parameter name="channel" required="true">
            <para>The current channel is bridged to the channel
            identified by the channel name, channel name prefix, or channel
            uniqueid.</para>
         </parameter>
         <parameter name="options">
            <optionlist>
               <option name="p">
                  <para>Play a courtesy tone to <replaceable>channel</replaceable>.</para>
               </option>
               <option name="F" argsep="^">
                  <argument name="context" required="false" />
                  <argument name="exten" required="false" />
                  <argument name="priority" required="true" />
                  <para>When the bridger hangs up, transfer the <emphasis>bridged</emphasis> party
                  to the specified destination and <emphasis>start</emphasis> execution at that location.</para>
                  <note>
                     <para>Any channel variables you want the called channel to inherit from the caller channel must be
                     prefixed with one or two underbars ('_').</para>
                  </note>
                  <note>
                     <para>This option will override the 'x' option</para>
                  </note>
               </option>
               <option name="F">
                  <para>When the bridger hangs up, transfer the <emphasis>bridged</emphasis> party
                  to the next priority of the current extension and <emphasis>start</emphasis> execution
                  at that location.</para>
                  <note>
                     <para>Any channel variables you want the called channel to inherit from the caller channel must be
                     prefixed with one or two underbars ('_').</para>
                  </note>
                  <note>
                     <para>Using this option from a Macro() or GoSub() might not make sense as there would be no return points.</para>
                  </note>
                  <note>
                     <para>This option will override the 'x' option</para>
                  </note>
               </option>

               <option name="h">
                  <para>Allow the called party to hang up by sending the
                  <replaceable>*</replaceable> DTMF digit.</para>
               </option>
               <option name="H">
                  <para>Allow the calling party to hang up by pressing the
                  <replaceable>*</replaceable> DTMF digit.</para>
               </option>
               <option name="k">
                  <para>Allow the called party to enable parking of the call by sending
                  the DTMF sequence defined for call parking in <filename>features.conf</filename>.</para>
               </option>
               <option name="K">
                  <para>Allow the calling party to enable parking of the call by sending
                   the DTMF sequence defined for call parking in <filename>features.conf</filename>.</para>
               </option>
               <option name="L(x[:y][:z])">
                  <para>Limit the call to <replaceable>x</replaceable> ms. Play a warning
                  when <replaceable>y</replaceable> ms are left. Repeat the warning every
                  <replaceable>z</replaceable> ms. The following special variables can be
                  used with this option:</para>
                  <variablelist>
                     <variable name="LIMIT_PLAYAUDIO_CALLER">
                        <para>Play sounds to the caller. yes|no (default yes)</para>
                     </variable>
                     <variable name="LIMIT_PLAYAUDIO_CALLEE">
                        <para>Play sounds to the callee. yes|no</para>
                     </variable>
                     <variable name="LIMIT_TIMEOUT_FILE">
                        <para>File to play when time is up.</para>
                     </variable>
                     <variable name="LIMIT_CONNECT_FILE">
                        <para>File to play when call begins.</para>
                     </variable>
                     <variable name="LIMIT_WARNING_FILE">
                        <para>File to play as warning if <replaceable>y</replaceable> is
                        defined. The default is to say the time remaining.</para>
                     </variable>
                  </variablelist>
               </option>
               <option name="S(x)">
                  <para>Hang up the call after <replaceable>x</replaceable> seconds *after* the called party has answered the call.</para>
               </option>
               <option name="t">
                  <para>Allow the called party to transfer the calling party by sending the
                  DTMF sequence defined in <filename>features.conf</filename>.</para>
               </option>
               <option name="T">
                  <para>Allow the calling party to transfer the called party by sending the
                  DTMF sequence defined in <filename>features.conf</filename>.</para>
               </option>
               <option name="w">
                  <para>Allow the called party to enable recording of the call by sending
                  the DTMF sequence defined for one-touch recording in <filename>features.conf</filename>.</para>
               </option>
               <option name="W">
                  <para>Allow the calling party to enable recording of the call by sending
                  the DTMF sequence defined for one-touch recording in <filename>features.conf</filename>.</para>
               </option>
               <option name="x">
                  <para>Cause the called party to be hung up after the bridge, instead of being
                  restarted in the dialplan.</para>
               </option>
            </optionlist>
         </parameter>
      </syntax>
      <description>
         <para>Allows the ability to bridge two channels via the dialplan.</para>
         <para>This application sets the following channel variable upon completion:</para>
         <variablelist>
            <variable name="BRIDGERESULT">
               <para>The result of the bridge attempt as a text string.</para>
               <value name="SUCCESS" />
               <value name="FAILURE" />
               <value name="LOOP" />
               <value name="NONEXISTENT" />
            </variable>
         </variablelist>
      </description>
      <see-also>
         <ref type="manager">Bridge</ref>
         <ref type="managerEvent">BridgeCreate</ref>
         <ref type="managerEvent">BridgeEnter</ref>
      </see-also>
   </application>
   <manager name="Bridge" language="en_US">
      <synopsis>
         Bridge two channels already in the PBX.
      </synopsis>
      <syntax>
         <xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
         <parameter name="Channel1" required="true">
            <para>Channel to Bridge to Channel2.</para>
         </parameter>
         <parameter name="Channel2" required="true">
            <para>Channel to Bridge to Channel1.</para>
         </parameter>
         <parameter name="Tone">
            <para>Play courtesy tone to Channel 2.</para>
            <enumlist>
               <enum name="no" />
               <enum name="Channel1" />
               <enum name="Channel2" />
               <enum name="Both" />
            </enumlist>
         </parameter>
      </syntax>
      <description>
         <para>Bridge together two channels already in the PBX.</para>
      </description>
      <see-also>
         <ref type="application">Bridge</ref>
         <ref type="managerEvent">BridgeCreate</ref>
         <ref type="managerEvent">BridgeEnter</ref>
         <ref type="manager">BridgeDestroy</ref>
         <ref type="manager">BridgeInfo</ref>
         <ref type="manager">BridgeKick</ref>
         <ref type="manager">BridgeList</ref>
      </see-also>
   </manager>
 ***/

typedef enum {
   FEATURE_INTERPRET_DETECT, /* Used by ast_feature_detect */
   FEATURE_INTERPRET_DO,     /* Used by feature_interpret */
   FEATURE_INTERPRET_CHECK,  /* Used by feature_check */
} feature_interpret_op;

struct ast_dial_features {
   /*! Channel's feature flags. */
   struct ast_flags my_features;
   /*! Bridge peer's feature flags. */
   struct ast_flags peer_features;
};

static void *dial_features_duplicate(void *data)
{
   struct ast_dial_features *df = data, *df_copy;

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

   memcpy(df_copy, df, sizeof(*df));

   return df_copy;
}

static const struct ast_datastore_info dial_features_info = {
   .type = "dial-features",
   .destroy = ast_free_ptr,
   .duplicate = dial_features_duplicate,
};

/*!
 * \internal
 * \brief Set the features datastore if it doesn't exist.
 *
 * \param chan Channel to add features datastore
 * \param my_features The channel's feature flags
 * \param peer_features The channel's bridge peer feature flags
 *
 * \retval TRUE if features datastore already existed.
 */
static int add_features_datastore(struct ast_channel *chan, const struct ast_flags *my_features, const struct ast_flags *peer_features)
{
   struct ast_datastore *datastore;
   struct ast_dial_features *dialfeatures;

   ast_channel_lock(chan);
   datastore = ast_channel_datastore_find(chan, &dial_features_info, NULL);
   ast_channel_unlock(chan);
   if (datastore) {
      /* Already exists. */
      return 1;
   }

   /* Create a new datastore with specified feature flags. */
   datastore = ast_datastore_alloc(&dial_features_info, NULL);
   if (!datastore) {
      ast_log(LOG_WARNING, "Unable to create channel features datastore.\n");
      return 0;
   }
   dialfeatures = ast_calloc(1, sizeof(*dialfeatures));
   if (!dialfeatures) {
      ast_log(LOG_WARNING, "Unable to allocate memory for feature flags.\n");
      ast_datastore_free(datastore);
      return 0;
   }
   ast_copy_flags(&dialfeatures->my_features, my_features, AST_FLAGS_ALL);
   ast_copy_flags(&dialfeatures->peer_features, peer_features, AST_FLAGS_ALL);
   datastore->inheritance = DATASTORE_INHERIT_FOREVER;
   datastore->data = dialfeatures;
   ast_channel_lock(chan);
   ast_channel_datastore_add(chan, datastore);
   ast_channel_unlock(chan);
   return 0;
}

struct ast_bridge_thread_obj
{
   struct ast_bridge_config bconfig;
   struct ast_channel *chan;
   struct ast_channel *peer;
   unsigned int return_to_pbx:1;
};

static void set_config_flags(struct ast_channel *chan, struct ast_bridge_config *config)
{
   ast_clear_flag(config, AST_FLAGS_ALL);

   if (ast_test_flag(&config->features_caller, AST_FEATURE_DTMF_MASK)) {
      ast_set_flag(config, AST_BRIDGE_DTMF_CHANNEL_0);
   }
   if (ast_test_flag(&config->features_callee, AST_FEATURE_DTMF_MASK)) {
      ast_set_flag(config, AST_BRIDGE_DTMF_CHANNEL_1);
   }

   if (!(ast_test_flag(config, AST_BRIDGE_DTMF_CHANNEL_0) && ast_test_flag(config, AST_BRIDGE_DTMF_CHANNEL_1))) {
      RAII_VAR(struct ao2_container *, applicationmap, NULL, ao2_cleanup);

      ast_channel_lock(chan);
      applicationmap = ast_get_chan_applicationmap(chan);
      ast_channel_unlock(chan);

      if (!applicationmap) {
         return;
      }

      /* If an applicationmap exists for this channel at all, then the channel needs the DTMF flag set */
      ast_set_flag(config, AST_BRIDGE_DTMF_CHANNEL_0);
   }
}

void ast_channel_log(char *title, struct ast_channel *chan);

void ast_channel_log(char *title, struct ast_channel *chan) /* for debug, this is handy enough to justify keeping it in the source */
{
   ast_log(LOG_NOTICE, "______ %s (%lx)______\n", title, (unsigned long) chan);
   ast_log(LOG_NOTICE, "CHAN: name: %s;  appl: %s; data: %s; contxt: %s;  exten: %s; pri: %d;\n",
      ast_channel_name(chan), ast_channel_appl(chan), ast_channel_data(chan),
      ast_channel_context(chan), ast_channel_exten(chan), ast_channel_priority(chan));
   ast_log(LOG_NOTICE, "CHAN: acctcode: %s;  dialcontext: %s; amaflags: %x; maccontxt: %s;  macexten: %s; macpri: %d;\n",
      ast_channel_accountcode(chan), ast_channel_dialcontext(chan), ast_channel_amaflags(chan),
      ast_channel_macrocontext(chan), ast_channel_macroexten(chan), ast_channel_macropriority(chan));
   ast_log(LOG_NOTICE, "CHAN: masq: %p;  masqr: %p; uniqueID: %s; linkedID:%s\n",
      ast_channel_masq(chan), ast_channel_masqr(chan),
      ast_channel_uniqueid(chan), ast_channel_linkedid(chan));
   if (ast_channel_masqr(chan)) {
      ast_log(LOG_NOTICE, "CHAN: masquerading as: %s;  cdr: %p;\n",
         ast_channel_name(ast_channel_masqr(chan)), ast_channel_cdr(ast_channel_masqr(chan)));
   }

   ast_log(LOG_NOTICE, "===== done ====\n");
}

static void set_bridge_features_on_config(struct ast_bridge_config *config, const char *features)
{
   const char *feature;

   if (ast_strlen_zero(features)) {
      return;
   }

   for (feature = features; *feature; feature++) {
      struct ast_flags *party;

      if (isupper(*feature)) {
         party = &config->features_caller;
      } else {
         party = &config->features_callee;
      }

      switch (tolower(*feature)) {
      case 't' :
         ast_set_flag(party, AST_FEATURE_REDIRECT);
         break;
      case 'k' :
         ast_set_flag(party, AST_FEATURE_PARKCALL);
         break;
      case 'h' :
         ast_set_flag(party, AST_FEATURE_DISCONNECT);
         break;
      case 'w' :
         ast_set_flag(party, AST_FEATURE_AUTOMON);
         break;
      case 'x' :
         ast_set_flag(party, AST_FEATURE_AUTOMIXMON);
         break;
      default :
         ast_log(LOG_WARNING, "Skipping unknown feature code '%c'\n", *feature);
         break;
      }
   }
}

static void add_features_datastores(struct ast_channel *caller, struct ast_channel *callee, struct ast_bridge_config *config)
{
   if (add_features_datastore(caller, &config->features_caller, &config->features_callee)) {
      /*
       * If we don't return here, then when we do a builtin_atxfer we
       * will copy the disconnect flags over from the atxfer to the
       * callee (Party C).
       */
      return;
   }

   add_features_datastore(callee, &config->features_callee, &config->features_caller);
}

static void bridge_config_set_limits_warning_values(struct ast_bridge_config *config, struct ast_bridge_features_limits *limits)
{
   if (config->end_sound) {
      ast_string_field_set(limits, duration_sound, config->end_sound);
   }

   if (config->warning_sound) {
      ast_string_field_set(limits, warning_sound, config->warning_sound);
   }

   if (config->start_sound) {
      ast_string_field_set(limits, connect_sound, config->start_sound);
   }

   limits->frequency = config->warning_freq;
   limits->warning = config->play_warning;
}

/*!
 * \internal brief Setup limit hook structures on calls that need limits
 *
 * \param config ast_bridge_config which provides the limit data
 * \param caller_limits pointer to an ast_bridge_features_limits struct which will store the caller side limits
 * \param callee_limits pointer to an ast_bridge_features_limits struct which will store the callee side limits
 */
static void bridge_config_set_limits(struct ast_bridge_config *config, struct ast_bridge_features_limits *caller_limits, struct ast_bridge_features_limits *callee_limits)
{
   if (ast_test_flag(&config->features_caller, AST_FEATURE_PLAY_WARNING)) {
      bridge_config_set_limits_warning_values(config, caller_limits);
   }

   if (ast_test_flag(&config->features_callee, AST_FEATURE_PLAY_WARNING)) {
      bridge_config_set_limits_warning_values(config, callee_limits);
   }

   caller_limits->duration = config->timelimit;
   callee_limits->duration = config->timelimit;
}

/*!
 * \internal
 * \brief Check if Monitor needs to be started on a channel.
 * \since 12.0.0
 *
 * \param chan The bridge considers this channel the caller.
 * \param peer The bridge considers this channel the callee.
 *
 * \return Nothing
 */
static void bridge_check_monitor(struct ast_channel *chan, struct ast_channel *peer)
{
   const char *value;
   const char *monitor_args = NULL;
   struct ast_channel *monitor_chan = NULL;

   ast_channel_lock(chan);
   value = pbx_builtin_getvar_helper(chan, "AUTO_MONITOR");
   if (!ast_strlen_zero(value)) {
      monitor_args = ast_strdupa(value);
      monitor_chan = chan;
   }
   ast_channel_unlock(chan);
   if (!monitor_chan) {
      ast_channel_lock(peer);
      value = pbx_builtin_getvar_helper(peer, "AUTO_MONITOR");
      if (!ast_strlen_zero(value)) {
         monitor_args = ast_strdupa(value);
         monitor_chan = peer;
      }
      ast_channel_unlock(peer);
   }
   if (monitor_chan) {
      struct ast_app *monitor_app;

      monitor_app = pbx_findapp("Monitor");
      if (monitor_app) {
         pbx_exec(monitor_chan, monitor_app, monitor_args);
      }
   }
}

/*!
 * \internal
 * \brief Send the peer channel on its way on bridge start failure.
 * \since 12.0.0
 *
 * \param chan Chan to put into autoservice.
 * \param peer Chan to send to after bridge goto or run hangup handlers and hangup.
 *
 * \return Nothing
 */
static void bridge_failed_peer_goto(struct ast_channel *chan, struct ast_channel *peer)
{
   if (ast_bridge_setup_after_goto(peer)
      || ast_pbx_start(peer)) {
      ast_autoservice_chan_hangup_peer(chan, peer);
   }
}

static int pre_bridge_setup(struct ast_channel *chan, struct ast_channel *peer, struct ast_bridge_config *config,
      struct ast_bridge_features *chan_features, struct ast_bridge_features *peer_features)
{
   int res;
   SCOPE_TRACE(1, "%s Peer: %s\n", ast_channel_name(chan), ast_channel_name(peer));

   set_bridge_features_on_config(config, pbx_builtin_getvar_helper(chan, "BRIDGE_FEATURES"));
   add_features_datastores(chan, peer, config);

   /*
    * This is an interesting case.  One example is if a ringing
    * channel gets redirected to an extension that picks up a
    * parked call.  This will make sure that the call taken out of
    * parking gets told that the channel it just got bridged to is
    * still ringing.
    */
   if (ast_channel_state(chan) == AST_STATE_RINGING
      && ast_channel_visible_indication(peer) != AST_CONTROL_RINGING) {
      ast_indicate(peer, AST_CONTROL_RINGING);
   }

   bridge_check_monitor(chan, peer);

   set_config_flags(chan, config);

   /* Answer if need be */

   res = 0;

   if (ast_channel_state(chan) != AST_STATE_UP) {
      res = ast_raw_answer_with_stream_topology(chan, config->answer_topology);
      if (res != 0) {
         return -1;
      }
   }


#ifdef FOR_DEBUG
   /* show the two channels and cdrs involved in the bridge for debug & devel purposes */
   ast_channel_log("Pre-bridge CHAN Channel info", chan);
   ast_channel_log("Pre-bridge PEER Channel info", peer);
#endif

   res = 0;
   ast_channel_lock(chan);
   ast_max_forwards_reset(chan);
   res |= ast_bridge_features_ds_append(chan, &config->features_caller);
   ast_channel_unlock(chan);
   ast_channel_lock(peer);
   ast_max_forwards_reset(peer);
   res |= ast_bridge_features_ds_append(peer, &config->features_callee);
   ast_channel_unlock(peer);

   if (res) {
      return -1;
   }

   if (config->timelimit) {
      struct ast_bridge_features_limits call_duration_limits_chan;
      struct ast_bridge_features_limits call_duration_limits_peer;
      int abandon_call = 0; /* TRUE if set limits fails so we can abandon the call. */

      if (ast_bridge_features_limits_construct(&call_duration_limits_chan)) {
         ast_log(LOG_ERROR, "Could not construct caller duration limits. Bridge canceled.\n");

         return -1;
      }

      if (ast_bridge_features_limits_construct(&call_duration_limits_peer)) {
         ast_log(LOG_ERROR, "Could not construct callee duration limits. Bridge canceled.\n");
         ast_bridge_features_limits_destroy(&call_duration_limits_chan);

         return -1;
      }

      bridge_config_set_limits(config, &call_duration_limits_chan, &call_duration_limits_peer);

      if (ast_bridge_features_set_limits(chan_features, &call_duration_limits_chan, 0)) {
         abandon_call = 1;
      }
      if (ast_bridge_features_set_limits(peer_features, &call_duration_limits_peer, 0)) {
         abandon_call = 1;
      }

      /* At this point we are done with the limits structs since they have been copied to the individual feature sets. */
      ast_bridge_features_limits_destroy(&call_duration_limits_chan);
      ast_bridge_features_limits_destroy(&call_duration_limits_peer);

      if (abandon_call) {
         ast_log(LOG_ERROR, "Could not set duration limits on one or more sides of the call. Bridge canceled.\n");
         return -1;
      }
   }

   return 0;
}

int ast_bridge_call_with_flags(struct ast_channel *chan, struct ast_channel *peer, struct ast_bridge_config *config, unsigned int flags)
{
   int res;
   struct ast_bridge *bridge;
   struct ast_bridge_features chan_features;
   struct ast_bridge_features *peer_features;
   SCOPE_TRACE(1, "%s Peer: %s\n", ast_channel_name(chan), ast_channel_name(peer));

   /* Setup features. */
   res = ast_bridge_features_init(&chan_features);
   peer_features = ast_bridge_features_new();
   if (res || !peer_features) {
      ast_bridge_features_destroy(peer_features);
      ast_bridge_features_cleanup(&chan_features);
      bridge_failed_peer_goto(chan, peer);
      return -1;
   }

   if (pre_bridge_setup(chan, peer, config, &chan_features, peer_features)) {
      ast_bridge_features_destroy(peer_features);
      ast_bridge_features_cleanup(&chan_features);
      bridge_failed_peer_goto(chan, peer);
      return -1;
   }

   /* Create bridge */
   bridge = ast_bridge_basic_new();
   if (!bridge) {
      ast_bridge_features_destroy(peer_features);
      ast_bridge_features_cleanup(&chan_features);
      bridge_failed_peer_goto(chan, peer);
      return -1;
   }

   ast_bridge_basic_set_flags(bridge, flags);

   /* Put peer into the bridge */
   if (ast_bridge_impart(bridge, peer, NULL, peer_features,
      AST_BRIDGE_IMPART_CHAN_INDEPENDENT | AST_BRIDGE_IMPART_INHIBIT_JOIN_COLP)) {
      ast_bridge_destroy(bridge, 0);
      ast_bridge_features_cleanup(&chan_features);
      bridge_failed_peer_goto(chan, peer);
      return -1;
   }

   /* Join bridge */
   ast_bridge_join(bridge, chan, NULL, &chan_features, NULL,
      AST_BRIDGE_JOIN_PASS_REFERENCE | AST_BRIDGE_JOIN_INHIBIT_JOIN_COLP);

   /*
    * If the bridge was broken for a hangup that isn't real, then
    * don't run the h extension, because the channel isn't really
    * hung up.  This should really only happen with
    * AST_SOFTHANGUP_ASYNCGOTO.
    */
   res = -1;
   ast_channel_lock(chan);
   if (ast_channel_softhangup_internal_flag(chan) & AST_SOFTHANGUP_ASYNCGOTO) {
      res = 0;
   }
   ast_channel_unlock(chan);

   ast_bridge_features_cleanup(&chan_features);

   if (res && config->end_bridge_callback) {
      config->end_bridge_callback(config->end_bridge_callback_data);
   }

   return res;
}

/*!
 * \brief bridge the call and set CDR
 *
 * \param chan The bridge considers this channel the caller.
 * \param peer The bridge considers this channel the callee.
 * \param config Configuration for this bridge.
 *
 * Set start time, check for two channels,check if monitor on
 * check for feature activation, create new CDR
 * \retval res on success.
 * \retval -1 on failure to bridge.
 */
int ast_bridge_call(struct ast_channel *chan, struct ast_channel *peer, struct ast_bridge_config *config)
{
   return ast_bridge_call_with_flags(chan, peer, config, 0);
}

enum play_tone_action {
   PLAYTONE_NONE = 0,
   PLAYTONE_CHANNEL1 = (1 << 0),
   PLAYTONE_CHANNEL2 = (1 << 1),
   PLAYTONE_BOTH = PLAYTONE_CHANNEL1 | PLAYTONE_CHANNEL2,
};

static enum play_tone_action parse_playtone(const char *playtone_val)
{
   if (ast_strlen_zero(playtone_val) || ast_false(playtone_val)) {
      return PLAYTONE_NONE;
   } if (!strcasecmp(playtone_val, "channel1")) {
      return PLAYTONE_CHANNEL1;
   } else if (!strcasecmp(playtone_val, "channel2") || ast_true(playtone_val)) {
      return PLAYTONE_CHANNEL2;
   } else if (!strcasecmp(playtone_val, "both")) {
      return PLAYTONE_BOTH;
   } else {
      /* Invalid input. Assume none */
      return PLAYTONE_NONE;
   }
}

/*!
 * \brief Bridge channels together
 * \param s
 * \param m
 *
 * Make sure valid channels were specified,
 * send errors if any of the channels could not be found/locked, answer channels if needed,
 * create the placeholder channels and grab the other channels
 * make the channels compatible, send error if we fail doing so
 * setup the bridge thread object and start the bridge.
 *
 * \retval 0
 */
static int action_bridge(struct mansession *s, const struct message *m)
{
   const char *channela = astman_get_header(m, "Channel1");
   const char *channelb = astman_get_header(m, "Channel2");
   enum play_tone_action playtone = parse_playtone(astman_get_header(m, "Tone"));
   RAII_VAR(struct ast_channel *, chana, NULL, ao2_cleanup);
   RAII_VAR(struct ast_channel *, chanb, NULL, ao2_cleanup);
   const char *chana_exten;
   const char *chana_context;
   int chana_priority;
   const char *chanb_exten;
   const char *chanb_context;
   int chanb_priority;
   struct ast_bridge *bridge;
   char buf[256];
   RAII_VAR(struct ast_features_xfer_config *, xfer_cfg_a, NULL, ao2_cleanup);
   RAII_VAR(struct ast_features_xfer_config *, xfer_cfg_b, NULL, ao2_cleanup);

   /* make sure valid channels were specified */
   if (ast_strlen_zero(channela) || ast_strlen_zero(channelb)) {
      astman_send_error(s, m, "Missing channel parameter in request");
      return 0;
   }

   ast_debug(1, "Performing Bridge action on %s and %s\n", channela, channelb);

   /* Start with chana */
   chana = ast_channel_get_by_name_prefix(channela, strlen(channela));
   if (!chana) {
      snprintf(buf, sizeof(buf), "Channel1 does not exist: %s", channela);
      astman_send_error(s, m, buf);
      return 0;
   }
   ast_channel_lock(chana);
   xfer_cfg_a = ast_get_chan_features_xfer_config(chana);
   chana_exten = ast_strdupa(ast_channel_exten(chana));
   chana_context = ast_strdupa(ast_channel_context(chana));
   chana_priority = ast_channel_priority(chana);
   if (ast_test_flag(ast_channel_flags(chana), AST_FLAG_IN_AUTOLOOP)) {
      chana_priority++;
   }
   ast_channel_unlock(chana);

   chanb = ast_channel_get_by_name_prefix(channelb, strlen(channelb));
   if (!chanb) {
      snprintf(buf, sizeof(buf), "Channel2 does not exist: %s", channelb);
      astman_send_error(s, m, buf);
      return 0;
   }
   ast_channel_lock(chanb);
   xfer_cfg_b = ast_get_chan_features_xfer_config(chanb);
   chanb_exten = ast_strdupa(ast_channel_exten(chanb));
   chanb_context = ast_strdupa(ast_channel_context(chanb));
   chanb_priority = ast_channel_priority(chanb);
   if (ast_test_flag(ast_channel_flags(chanb), AST_FLAG_IN_AUTOLOOP)) {
      chanb_priority++;
   }
   ast_channel_unlock(chanb);

   bridge = ast_bridge_basic_new();
   if (!bridge) {
      astman_send_error(s, m, "Unable to create bridge\n");
      return 0;
   }

   ast_bridge_set_after_goto(chana, chana_context, chana_exten, chana_priority);
   if (ast_bridge_add_channel(bridge, chana, NULL, playtone & PLAYTONE_CHANNEL1, xfer_cfg_a ? xfer_cfg_a->xfersound : NULL)) {
      snprintf(buf, sizeof(buf), "Unable to add Channel1 to bridge: %s", ast_channel_name(chana));
      astman_send_error(s, m, buf);
      ast_bridge_destroy(bridge, 0);
      return 0;
   }

   ast_bridge_set_after_goto(chanb, chanb_context, chanb_exten, chanb_priority);
   if (ast_bridge_add_channel(bridge, chanb, NULL, playtone & PLAYTONE_CHANNEL2, xfer_cfg_b ? xfer_cfg_b->xfersound : NULL)) {
      snprintf(buf, sizeof(buf), "Unable to add Channel2 to bridge: %s", ast_channel_name(chanb));
      astman_send_error(s, m, buf);
      ast_bridge_destroy(bridge, 0);
      return 0;
   }

   astman_send_ack(s, m, "Channels have been bridged");
   ao2_cleanup(bridge);

   return 0;
}

static char *app_bridge = "Bridge";

enum {
   BRIDGE_OPT_PLAYTONE = (1 << 0),
   OPT_CALLEE_HANGUP =  (1 << 1),
   OPT_CALLER_HANGUP =  (1 << 2),
   OPT_DURATION_LIMIT = (1 << 3),
   OPT_DURATION_STOP =  (1 << 4),
   OPT_CALLEE_TRANSFER = (1 << 5),
   OPT_CALLER_TRANSFER = (1 << 6),
   OPT_CALLEE_MONITOR = (1 << 7),
   OPT_CALLER_MONITOR = (1 << 8),
   OPT_CALLEE_PARK = (1 << 9),
   OPT_CALLER_PARK = (1 << 10),
   OPT_CALLEE_KILL = (1 << 11),
   OPT_CALLEE_GO_ON = (1 << 12),
};

enum {
   OPT_ARG_DURATION_LIMIT = 0,
   OPT_ARG_DURATION_STOP,
   OPT_ARG_CALLEE_GO_ON,
   /* note: this entry _MUST_ be the last one in the enum */
   OPT_ARG_ARRAY_SIZE,
};

AST_APP_OPTIONS(bridge_exec_options, BEGIN_OPTIONS
   AST_APP_OPTION('p', BRIDGE_OPT_PLAYTONE),
   AST_APP_OPTION_ARG('F', OPT_CALLEE_GO_ON, OPT_ARG_CALLEE_GO_ON),
   AST_APP_OPTION('h', OPT_CALLEE_HANGUP),
   AST_APP_OPTION('H', OPT_CALLER_HANGUP),
   AST_APP_OPTION('k', OPT_CALLEE_PARK),
   AST_APP_OPTION('K', OPT_CALLER_PARK),
   AST_APP_OPTION_ARG('L', OPT_DURATION_LIMIT, OPT_ARG_DURATION_LIMIT),
   AST_APP_OPTION_ARG('S', OPT_DURATION_STOP, OPT_ARG_DURATION_STOP),
   AST_APP_OPTION('t', OPT_CALLEE_TRANSFER),
   AST_APP_OPTION('T', OPT_CALLER_TRANSFER),
   AST_APP_OPTION('w', OPT_CALLEE_MONITOR),
   AST_APP_OPTION('W', OPT_CALLER_MONITOR),
   AST_APP_OPTION('x', OPT_CALLEE_KILL),
END_OPTIONS );

int ast_bridge_timelimit(struct ast_channel *chan, struct ast_bridge_config *config,
   char *parse, struct timeval *calldurationlimit)
{
   char *stringp = ast_strdupa(parse);
   char *limit_str, *warning_str, *warnfreq_str;
   const char *var;
   int play_to_caller = 0, play_to_callee = 0;
   int delta;

   limit_str = strsep(&stringp, ":");
   warning_str = strsep(&stringp, ":");
   warnfreq_str = strsep(&stringp, ":");

   config->timelimit = atol(limit_str);
   if (warning_str)
      config->play_warning = atol(warning_str);
   if (warnfreq_str)
      config->warning_freq = atol(warnfreq_str);

   if (!config->timelimit) {
      ast_log(LOG_WARNING, "Bridge does not accept L(%s)\n", limit_str);
      config->timelimit = config->play_warning = config->warning_freq = 0;
      config->warning_sound = NULL;
      return -1; /* error */
   } else if ( (delta = config->play_warning - config->timelimit) > 0) {
      int w = config->warning_freq;

      /*
       * If the first warning is requested _after_ the entire call
       * would end, and no warning frequency is requested, then turn
       * off the warning. If a warning frequency is requested, reduce
       * the 'first warning' time by that frequency until it falls
       * within the call's total time limit.
       *
       * Graphically:
       *                timelim->|    delta        |<-playwarning
       *      0__________________|_________________|
       *                       | w  |    |    |    |
       *
       * so the number of intervals to cut is 1+(delta-1)/w
       */
      if (w == 0) {
         config->play_warning = 0;
      } else {
         config->play_warning -= w * ( 1 + (delta-1)/w );
         if (config->play_warning < 1)
            config->play_warning = config->warning_freq = 0;
      }
   }

   ast_channel_lock(chan);

   var = pbx_builtin_getvar_helper(chan, "LIMIT_PLAYAUDIO_CALLER");
   play_to_caller = var ? ast_true(var) : 1;

   var = pbx_builtin_getvar_helper(chan, "LIMIT_PLAYAUDIO_CALLEE");
   play_to_callee = var ? ast_true(var) : 0;

   if (!play_to_caller && !play_to_callee)
      play_to_caller = 1;

   var = pbx_builtin_getvar_helper(chan, "LIMIT_WARNING_FILE");
   config->warning_sound = !ast_strlen_zero(var) ? ast_strdup(var) : ast_strdup("timeleft");

   /* The code looking at config wants a NULL, not just "", to decide
    * that the message should not be played, so we replace "" with NULL.
    * Note, pbx_builtin_getvar_helper _can_ return NULL if the variable is
    * not found.
    */

   var = pbx_builtin_getvar_helper(chan, "LIMIT_TIMEOUT_FILE");
   config->end_sound = !ast_strlen_zero(var) ? ast_strdup(var) : NULL;

   var = pbx_builtin_getvar_helper(chan, "LIMIT_CONNECT_FILE");
   config->start_sound = !ast_strlen_zero(var) ? ast_strdup(var) : NULL;

   ast_channel_unlock(chan);

   /* undo effect of S(x) in case they are both used */
   calldurationlimit->tv_sec = 0;
   calldurationlimit->tv_usec = 0;

   /* more efficient to do it like S(x) does since no advanced opts */
   if (!config->play_warning && !config->start_sound && !config->end_sound && config->timelimit) {
      calldurationlimit->tv_sec = config->timelimit / 1000;
      calldurationlimit->tv_usec = (config->timelimit % 1000) * 1000;
      ast_verb(3, "Setting call duration limit to %.3lf seconds.\n",
         calldurationlimit->tv_sec + calldurationlimit->tv_usec / 1000000.0);
      play_to_caller = 0;
      play_to_callee = 0;
      config->timelimit = 0;
      config->play_warning = 0;
      config->warning_freq = 0;
   } else {
      ast_verb(4, "Limit Data for this call:\n");
      ast_verb(4, "timelimit      = %ld ms (%.3lf s)\n", config->timelimit, config->timelimit / 1000.0);
      ast_verb(4, "play_warning   = %ld ms (%.3lf s)\n", config->play_warning, config->play_warning / 1000.0);
      ast_verb(4, "play_to_caller = %s\n", play_to_caller ? "yes" : "no");
      ast_verb(4, "play_to_callee = %s\n", play_to_callee ? "yes" : "no");
      ast_verb(4, "warning_freq   = %ld ms (%.3lf s)\n", config->warning_freq, config->warning_freq / 1000.0);
      ast_verb(4, "start_sound    = %s\n", S_OR(config->start_sound, ""));
      ast_verb(4, "warning_sound  = %s\n", config->warning_sound);
      ast_verb(4, "end_sound      = %s\n", S_OR(config->end_sound, ""));
   }
   if (play_to_caller)
      ast_set_flag(&(config->features_caller), AST_FEATURE_PLAY_WARNING);
   if (play_to_callee)
      ast_set_flag(&(config->features_callee), AST_FEATURE_PLAY_WARNING);
   return 0;
}


/*!
 * \brief Bridge channels
 * \param chan
 * \param data channel to bridge with.
 *
 * Split data, check we aren't bridging with ourself, check valid channel,
 * answer call if not already, check compatible channels, setup bridge config
 * now bridge call, if transferred party hangs up return to PBX extension.
 */
static int bridge_exec(struct ast_channel *chan, const char *data)
{
   struct ast_channel *current_dest_chan = NULL;
   char *tmp_data  = NULL;
   struct ast_flags opts = { 0, };
   struct ast_bridge_config bconfig = { { 0, }, };
   char *opt_args[OPT_ARG_ARRAY_SIZE];
   struct timeval calldurationlimit = { 0, };
   const char *context;
   const char *extension;
   int priority;
   int bridge_add_failed;
   int res = -1;
   struct ast_bridge_features chan_features;
   struct ast_bridge_features *peer_features;
   struct ast_bridge *bridge;
   struct ast_features_xfer_config *xfer_cfg;

   AST_DECLARE_APP_ARGS(args,
      AST_APP_ARG(dest_chan);
      AST_APP_ARG(options);
   );

   tmp_data = ast_strdupa(data ?: "");
   AST_STANDARD_APP_ARGS(args, tmp_data);
   if (!ast_strlen_zero(args.options)) {
      ast_app_parse_options(bridge_exec_options, &opts, opt_args, args.options);
   }

   /* make sure we have a valid end point */
   if (!ast_strlen_zero(args.dest_chan)) {
      current_dest_chan = ast_channel_get_by_name_prefix(args.dest_chan,
         strlen(args.dest_chan));
   }
   if (!current_dest_chan) {
      ast_verb(4, "Bridge failed because channel '%s' does not exist\n",
         args.dest_chan ?: "");
      pbx_builtin_setvar_helper(chan, "BRIDGERESULT", "NONEXISTENT");
      return 0;
   }

   /* avoid bridge with ourselves */
   if (chan == current_dest_chan) {
      ast_channel_unref(current_dest_chan);
      ast_log(LOG_WARNING, "Unable to bridge channel %s with itself\n", ast_channel_name(chan));
      pbx_builtin_setvar_helper(chan, "BRIDGERESULT", "LOOP");
      return 0;
   }

   if (ast_test_flag(&opts, OPT_DURATION_LIMIT)
      && !ast_strlen_zero(opt_args[OPT_ARG_DURATION_LIMIT])
      && ast_bridge_timelimit(chan, &bconfig, opt_args[OPT_ARG_DURATION_LIMIT], &calldurationlimit)) {
      goto done;
   }

   if (ast_test_flag(&opts, OPT_CALLEE_TRANSFER))
      ast_set_flag(&(bconfig.features_callee), AST_FEATURE_REDIRECT);
   if (ast_test_flag(&opts, OPT_CALLER_TRANSFER))
      ast_set_flag(&(bconfig.features_caller), AST_FEATURE_REDIRECT);
   if (ast_test_flag(&opts, OPT_CALLEE_HANGUP))
      ast_set_flag(&(bconfig.features_callee), AST_FEATURE_DISCONNECT);
   if (ast_test_flag(&opts, OPT_CALLER_HANGUP))
      ast_set_flag(&(bconfig.features_caller), AST_FEATURE_DISCONNECT);
   if (ast_test_flag(&opts, OPT_CALLEE_MONITOR))
      ast_set_flag(&(bconfig.features_callee), AST_FEATURE_AUTOMON);
   if (ast_test_flag(&opts, OPT_CALLER_MONITOR))
      ast_set_flag(&(bconfig.features_caller), AST_FEATURE_AUTOMON);
   if (ast_test_flag(&opts, OPT_CALLEE_PARK))
      ast_set_flag(&(bconfig.features_callee), AST_FEATURE_PARKCALL);
   if (ast_test_flag(&opts, OPT_CALLER_PARK))
      ast_set_flag(&(bconfig.features_caller), AST_FEATURE_PARKCALL);

   /* Setup after bridge goto location. */
   if (ast_test_flag(&opts, OPT_CALLEE_GO_ON)) {
      ast_channel_lock(chan);
      context = ast_strdupa(ast_channel_context(chan));
      extension = ast_strdupa(ast_channel_exten(chan));
      priority = ast_channel_priority(chan);
      ast_channel_unlock(chan);
      ast_bridge_set_after_go_on(current_dest_chan, context, extension, priority,
         opt_args[OPT_ARG_CALLEE_GO_ON]);
   } else if (!ast_test_flag(&opts, OPT_CALLEE_KILL)) {
      ast_channel_lock(current_dest_chan);
      context = ast_strdupa(ast_channel_context(current_dest_chan));
      extension = ast_strdupa(ast_channel_exten(current_dest_chan));
      priority = ast_channel_priority(current_dest_chan);
      ast_channel_unlock(current_dest_chan);
      ast_bridge_set_after_go_on(current_dest_chan, context, extension, priority, NULL);
   }

   if (ast_bridge_features_init(&chan_features)) {
      ast_bridge_features_cleanup(&chan_features);
      goto done;
   }

   peer_features = ast_bridge_features_new();
   if (!peer_features) {
      ast_bridge_features_cleanup(&chan_features);
      goto done;
   }

   if (pre_bridge_setup(chan, current_dest_chan, &bconfig, &chan_features, peer_features)) {
      ast_bridge_features_destroy(peer_features);
      ast_bridge_features_cleanup(&chan_features);
      goto done;
   }

   bridge = ast_bridge_basic_new();
   if (!bridge) {
      ast_bridge_features_destroy(peer_features);
      ast_bridge_features_cleanup(&chan_features);
      goto done;
   }

   ast_channel_lock(current_dest_chan);
   xfer_cfg = ast_get_chan_features_xfer_config(current_dest_chan);
   ast_channel_unlock(current_dest_chan);
   bridge_add_failed = ast_bridge_add_channel(bridge, current_dest_chan, peer_features,
      ast_test_flag(&opts, BRIDGE_OPT_PLAYTONE),
      xfer_cfg ? xfer_cfg->xfersound : NULL);
   ao2_cleanup(xfer_cfg);
   if (bridge_add_failed) {
      ast_bridge_features_cleanup(&chan_features);
      ast_bridge_destroy(bridge, 0);
      goto done;
   }

   /* Don't keep the channel ref in case it was not already in a bridge. */
   current_dest_chan = ast_channel_unref(current_dest_chan);

   res = ast_bridge_join(bridge, chan, NULL, &chan_features, NULL,
      AST_BRIDGE_JOIN_PASS_REFERENCE);

   ast_bridge_features_cleanup(&chan_features);

done:
   if (res == -1) {
      pbx_builtin_setvar_helper(chan, "BRIDGERESULT", "FAILURE");
   } else {
      pbx_builtin_setvar_helper(chan, "BRIDGERESULT", "SUCCESS");
   }

   ast_free((char *) bconfig.warning_sound);
   ast_free((char *) bconfig.end_sound);
   ast_free((char *) bconfig.start_sound);

   ast_channel_cleanup(current_dest_chan);
   return 0;
}

static int unload_module(void)
{
   unload_features_config();

   ast_manager_unregister("Bridge");

   ast_unregister_application(app_bridge);

   return 0;
}

static int load_module(void)
{
   int res;

   res = load_features_config();
   res |= ast_register_application2(app_bridge, bridge_exec, NULL, NULL, NULL);
   res |= ast_manager_register_xml_core("Bridge", EVENT_FLAG_CALL, action_bridge);

   return res ? AST_MODULE_LOAD_FAILURE : AST_MODULE_LOAD_SUCCESS;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "Call Features",
   .support_level = AST_MODULE_SUPPORT_CORE,
   .load = load_module,
   .unload = unload_module,
   .reload = reload_features_config,
   .load_pri = AST_MODPRI_CORE,
   .requires = "extconfig",
);