bridge_basic.c

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013 Digium, Inc.
 *
 * Richard Mudgett <rmudgett@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 Basic bridge class.  It is a subclass of struct ast_bridge.
 *
 * \author Richard Mudgett <rmudgett@digium.com>
 *
 * See Also:
 * \arg \ref AstCREDITS
 */


#include "asterisk.h"

ASTERISK_REGISTER_FILE()

#include "asterisk/channel.h"
#include "asterisk/utils.h"
#include "asterisk/linkedlists.h"
#include "asterisk/bridge.h"
#include "asterisk/bridge_internal.h"
#include "asterisk/bridge_basic.h"
#include "asterisk/bridge_after.h"
#include "asterisk/astobj2.h"
#include "asterisk/features_config.h"
#include "asterisk/pbx.h"
#include "asterisk/file.h"
#include "asterisk/app.h"
#include "asterisk/dial.h"
#include "asterisk/stasis_bridges.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/features.h"
#include "asterisk/format_cache.h"
#include "asterisk/test.h"

#define NORMAL_FLAGS	(AST_BRIDGE_FLAG_DISSOLVE_HANGUP | AST_BRIDGE_FLAG_DISSOLVE_EMPTY \
			| AST_BRIDGE_FLAG_SMART)

#define TRANSFER_FLAGS AST_BRIDGE_FLAG_SMART

struct attended_transfer_properties;

enum bridge_basic_personality_type {
	/*! Index for "normal" basic bridge personality */
	BRIDGE_BASIC_PERSONALITY_NORMAL,
	/*! Index for attended transfer basic bridge personality */
	BRIDGE_BASIC_PERSONALITY_ATXFER,
	/*! Indicates end of enum. Must always remain the last element */
	BRIDGE_BASIC_PERSONALITY_END,
};

/*!
 * \brief Change basic bridge personality
 *
 * Changing personalities allows for the bridge to remain in use but have
 * properties such as its v_table and its flags change.
 *
 * \param bridge The bridge
 * \param type The personality to change the bridge to
 * \user_data Private data to attach to the personality.
 */
static void bridge_basic_change_personality(struct ast_bridge *bridge,
		enum bridge_basic_personality_type type, void *user_data);

/* ------------------------------------------------------------------- */

static const struct ast_datastore_info dtmf_features_info = {
	.type = "bridge-dtmf-features",
	.destroy = ast_free_ptr,
};

/*!
 * \internal
 * \since 12.0.0
 * \brief read a feature code character and set it on for the give feature_flags struct
 *
 * \param feature_flags flags being modifed
 * \param feature feature code provided - should be an uppercase letter
 *
 * \retval 0 if the feature was set successfully
 * \retval -1 failure because the requested feature code isn't handled by this function
 */
static int set_feature_flag_from_char(struct ast_flags *feature_flags, char feature)
{
	switch (feature) {
	case 'T':
		ast_set_flag(feature_flags, AST_FEATURE_REDIRECT);
		return 0;
	case 'K':
		ast_set_flag(feature_flags, AST_FEATURE_PARKCALL);
		return 0;
	case 'H':
		ast_set_flag(feature_flags, AST_FEATURE_DISCONNECT);
		return 0;
	case 'W':
		ast_set_flag(feature_flags, AST_FEATURE_AUTOMON);
		return 0;
	case 'X':
		ast_set_flag(feature_flags, AST_FEATURE_AUTOMIXMON);
		return 0;
	default:
		return -1;
	}
}

/*!
 * \internal
 * \since 12.0.0
 * \brief Write a features string to a string buffer based on the feature flags provided
 *
 * \param feature_flags pointer to the feature flags to write from.
 * \param buffer pointer to a string buffer to write the features
 * \param buffer_size size of the buffer provided (should be able to fit all feature codes)
 *
 * \retval 0 on successful write
 * \retval -1 failure due to running out of buffer space
 */
static int dtmf_features_flags_to_string(struct ast_flags *feature_flags, char *buffer, size_t buffer_size)
{
	size_t buffer_expended = 0;
	unsigned int cur_feature;
	static const struct {
		char letter;
		unsigned int flag;
	} associations[] = {
		{ 'T', AST_FEATURE_REDIRECT },
		{ 'K', AST_FEATURE_PARKCALL },
		{ 'H', AST_FEATURE_DISCONNECT },
		{ 'W', AST_FEATURE_AUTOMON },
		{ 'X', AST_FEATURE_AUTOMIXMON },
	};

	for (cur_feature = 0; cur_feature < ARRAY_LEN(associations); cur_feature++) {
		if (ast_test_flag(feature_flags, associations[cur_feature].flag)) {
			if (buffer_expended == buffer_size - 1) {
				buffer[buffer_expended] = '\0';
				return -1;
			}
			buffer[buffer_expended++] = associations[cur_feature].letter;
		}
	}

	buffer[buffer_expended] = '\0';
	return 0;
}

static int build_dtmf_features(struct ast_flags *flags, const char *features)
{
	const char *feature;

	char missing_features[strlen(features) + 1];
	size_t number_of_missing_features = 0;

	for (feature = features; *feature; feature++) {
		if (!isupper(*feature)) {
			ast_log(LOG_ERROR, "Features string '%s' rejected because it contains non-uppercase feature.\n", features);
			return -1;
		}

		if (set_feature_flag_from_char(flags, *feature)) {
			missing_features[number_of_missing_features++] = *feature;
		}
	}

	missing_features[number_of_missing_features] = '\0';

	if (number_of_missing_features) {
		ast_log(LOG_WARNING, "Features '%s' from features string '%s' can not be applied.\n", missing_features, features);
	}

	return 0;
}

int ast_bridge_features_ds_set_string(struct ast_channel *chan, const char *features)
{
	struct ast_flags flags = {0};

	if (build_dtmf_features(&flags, features)) {
		return -1;
	}

	ast_channel_lock(chan);
	if (ast_bridge_features_ds_set(chan, &flags)) {
		ast_channel_unlock(chan);
		ast_log(LOG_ERROR, "Failed to apply features datastore for '%s' to channel '%s'\n", features, ast_channel_name(chan));
		return -1;
	}
	ast_channel_unlock(chan);

	return 0;
}

int ast_bridge_features_ds_get_string(struct ast_channel *chan, char *buffer, size_t buf_size)
{
	struct ast_flags *channel_flags;
	struct ast_flags held_copy;

	ast_channel_lock(chan);
	if (!(channel_flags = ast_bridge_features_ds_get(chan))) {
		ast_channel_unlock(chan);
		return -1;
	}
	held_copy = *channel_flags;
	ast_channel_unlock(chan);

	return dtmf_features_flags_to_string(&held_copy, buffer, buf_size);
}

static int bridge_features_ds_set_full(struct ast_channel *chan, struct ast_flags *flags, int replace)
{
	struct ast_datastore *datastore;
	struct ast_flags *ds_flags;

	datastore = ast_channel_datastore_find(chan, &dtmf_features_info, NULL);
	if (datastore) {
		ds_flags = datastore->data;
		if (replace) {
			*ds_flags = *flags;
		} else {
			flags->flags = flags->flags | ds_flags->flags;
			*ds_flags = *flags;
		}
		return 0;
	}

	datastore = ast_datastore_alloc(&dtmf_features_info, NULL);
	if (!datastore) {
		return -1;
	}

	ds_flags = ast_malloc(sizeof(*ds_flags));
	if (!ds_flags) {
		ast_datastore_free(datastore);
		return -1;
	}

	*ds_flags = *flags;
	datastore->data = ds_flags;
	ast_channel_datastore_add(chan, datastore);
	return 0;
}

int ast_bridge_features_ds_set(struct ast_channel *chan, struct ast_flags *flags)
{
	return bridge_features_ds_set_full(chan, flags, 1);
}

int ast_bridge_features_ds_append(struct ast_channel *chan, struct ast_flags *flags)
{
	return bridge_features_ds_set_full(chan, flags, 0);
}

struct ast_flags *ast_bridge_features_ds_get(struct ast_channel *chan)
{
	struct ast_datastore *datastore;

	datastore = ast_channel_datastore_find(chan, &dtmf_features_info, NULL);
	if (!datastore) {
		return NULL;
	}
	return datastore->data;
}

/*!
 * \internal
 * \brief Determine if we should dissolve the bridge from a hangup.
 * \since 12.0.0
 *
 * \param bridge_channel Channel executing the feature
 * \param hook_pvt Private data passed in when the hook was created
 *
 * \retval 0 Keep the callback hook.
 * \retval -1 Remove the callback hook.
 */
static int basic_hangup_hook(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
{
	int bridge_count = 0;
	struct ast_bridge_channel *iter;

	ast_bridge_channel_lock_bridge(bridge_channel);
	AST_LIST_TRAVERSE(&bridge_channel->bridge->channels, iter, entry) {
		if (iter != bridge_channel && iter->state == BRIDGE_CHANNEL_STATE_WAIT) {
			++bridge_count;
		}
	}
	if (2 <= bridge_count) {
		/* Just allow this channel to leave the multi-party bridge. */
		ast_bridge_channel_leave_bridge(bridge_channel,
			BRIDGE_CHANNEL_STATE_END_NO_DISSOLVE, 0);
	}
	ast_bridge_unlock(bridge_channel->bridge);
	return 0;
}

/*!
 * \brief Details for specific basic bridge personalities
 */
struct personality_details {
	/*! The v_table to use for this personality */
	struct ast_bridge_methods *v_table;
	/*! Flags to set on this type of bridge */
	unsigned int bridge_flags;
	/*! User data for this personality. If used, must be an ao2 object */
	void *pvt;
	/*! Callback to be called when changing to the personality */
	void (*on_personality_change)(struct ast_bridge *bridge);
};

/*!
 * \brief structure that organizes different personalities for basic bridges.
 */
struct bridge_basic_personality {
	/*! The current bridge personality in use */
	enum bridge_basic_personality_type current;
	/*! Array of details for the types of bridge personalities supported */
	struct personality_details details[BRIDGE_BASIC_PERSONALITY_END];
};

/*
 * \internal
 * \brief Get the extension for a given builtin feature.
 *
 * \param chan Get the feature extension for this channel.
 * \param feature_name features.conf name of feature.
 * \param buf Where to put the extension.
 * \param len Length of the given extension buffer.
 *
 * \retval 0 success
 * \retval non-zero failiure
 */
static int builtin_feature_get_exten(struct ast_channel *chan, const char *feature_name, char *buf, size_t len)
{
	SCOPED_CHANNELLOCK(lock, chan);

	return ast_get_builtin_feature(chan, feature_name, buf, len);
}

/*!
 * \internal
 * \brief Helper to add a builtin DTMF feature hook to the features struct.
 * \since 12.0.0
 *
 * \param features Bridge features to setup.
 * \param chan Get features from this channel.
 * \param flags Feature flags on the channel.
 * \param feature_flag Feature flag to test.
 * \param feature_name features.conf name of feature.
 * \param feature_bridge Bridge feature enum to get hook callback.
 *
 * \retval 0 on success.
 * \retval -1 on error.
 */
static int builtin_features_helper(struct ast_bridge_features *features, struct ast_channel *chan,
	struct ast_flags *flags, unsigned int feature_flag, const char *feature_name, enum ast_bridge_builtin_feature feature_bridge)
{
	char dtmf[AST_FEATURE_MAX_LEN];
	int res;

	res = 0;
	if (ast_test_flag(flags, feature_flag)
		&& !builtin_feature_get_exten(chan, feature_name, dtmf, sizeof(dtmf))
		&& !ast_strlen_zero(dtmf)) {
		res = ast_bridge_features_enable(features, feature_bridge, dtmf, NULL, NULL,
			AST_BRIDGE_HOOK_REMOVE_ON_PULL | AST_BRIDGE_HOOK_REMOVE_ON_PERSONALITY_CHANGE);
		if (res) {
			ast_log(LOG_ERROR, "Channel %s: Requested DTMF feature %s not available.\n",
				ast_channel_name(chan), feature_name);
		}
	}

	return res;
}

/*!
 * \internal
 * \brief Setup bridge builtin features.
 * \since 12.0.0
 *
 * \param features Bridge features to setup.
 * \param chan Get features from this channel.
 *
 * \retval 0 on success.
 * \retval -1 on error.
 */
static int setup_bridge_features_builtin(struct ast_bridge_features *features, struct ast_channel *chan)
{
	struct ast_flags *flags;
	int res;

	ast_channel_lock(chan);
	flags = ast_bridge_features_ds_get(chan);
	ast_channel_unlock(chan);
	if (!flags) {
		return 0;
	}

	res = 0;
	res |= builtin_features_helper(features, chan, flags, AST_FEATURE_REDIRECT, "blindxfer", AST_BRIDGE_BUILTIN_BLINDTRANSFER);
	res |= builtin_features_helper(features, chan, flags, AST_FEATURE_REDIRECT, "atxfer", AST_BRIDGE_BUILTIN_ATTENDEDTRANSFER);
	res |= builtin_features_helper(features, chan, flags, AST_FEATURE_DISCONNECT, "disconnect", AST_BRIDGE_BUILTIN_HANGUP);
	res |= builtin_features_helper(features, chan, flags, AST_FEATURE_PARKCALL, "parkcall", AST_BRIDGE_BUILTIN_PARKCALL);
	res |= builtin_features_helper(features, chan, flags, AST_FEATURE_AUTOMON, "automon", AST_BRIDGE_BUILTIN_AUTOMON);
	res |= builtin_features_helper(features, chan, flags, AST_FEATURE_AUTOMIXMON, "automixmon", AST_BRIDGE_BUILTIN_AUTOMIXMON);

	return res ? -1 : 0;
}

struct dynamic_dtmf_hook_run {
	/*! Offset into app_name[] where the channel name that activated the hook starts. */
	int activated_offset;
	/*! Offset into app_name[] where the dynamic feature name starts. */
	int feature_offset;
	/*! Offset into app_name[] where the MOH class name starts.  (zero if no MOH) */
	int moh_offset;
	/*! Offset into app_name[] where the application argument string starts. (zero if no arguments) */
	int app_args_offset;
	/*! Application name to run. */
	char app_name[0];
};

static void dynamic_dtmf_hook_callback(struct ast_bridge_channel *bridge_channel,
	const void *payload, size_t payload_size)
{
	struct ast_channel *chan = bridge_channel->chan;
	const struct dynamic_dtmf_hook_run *run_data = payload;

	pbx_builtin_setvar_helper(chan, "DYNAMIC_FEATURENAME",
		&run_data->app_name[run_data->feature_offset]);
	pbx_builtin_setvar_helper(chan, "DYNAMIC_WHO_ACTIVATED",
		&run_data->app_name[run_data->activated_offset]);

	ast_bridge_channel_run_app(bridge_channel, run_data->app_name,
		run_data->app_args_offset ? &run_data->app_name[run_data->app_args_offset] : NULL,
		run_data->moh_offset ? &run_data->app_name[run_data->moh_offset] : NULL);
}

struct dynamic_dtmf_hook_data {
	/*! Which side of bridge to run app (AST_FEATURE_FLAG_ONSELF/AST_FEATURE_FLAG_ONPEER) */
	unsigned int flags;
	/*! Offset into app_name[] where the dynamic feature name starts. */
	int feature_offset;
	/*! Offset into app_name[] where the MOH class name starts.  (zero if no MOH) */
	int moh_offset;
	/*! Offset into app_name[] where the application argument string starts. (zero if no arguments) */
	int app_args_offset;
	/*! Application name to run. */
	char app_name[0];
};

/*!
 * \internal
 * \brief Activated dynamic DTMF feature hook.
 * \since 12.0.0
 *
 * \param bridge_channel Channel executing the feature
 * \param hook_pvt Private data passed in when the hook was created
 *
 * \retval 0 Keep the callback hook.
 * \retval -1 Remove the callback hook.
 */
static int dynamic_dtmf_hook_trip(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
{
	struct dynamic_dtmf_hook_data *pvt = hook_pvt;
	struct dynamic_dtmf_hook_run *run_data;
	const char *activated_name;
	size_t len_name;
	size_t len_args;
	size_t len_moh;
	size_t len_feature;
	size_t len_activated;
	size_t len_data;

	/* Determine lengths of things. */
	len_name = strlen(pvt->app_name) + 1;
	len_args = pvt->app_args_offset ? strlen(&pvt->app_name[pvt->app_args_offset]) + 1 : 0;
	len_moh = pvt->moh_offset ? strlen(&pvt->app_name[pvt->moh_offset]) + 1 : 0;
	len_feature = strlen(&pvt->app_name[pvt->feature_offset]) + 1;
	ast_channel_lock(bridge_channel->chan);
	activated_name = ast_strdupa(ast_channel_name(bridge_channel->chan));
	ast_channel_unlock(bridge_channel->chan);
	len_activated = strlen(activated_name) + 1;
	len_data = sizeof(*run_data) + len_name + len_args + len_moh + len_feature + len_activated;

	/* Fill in dynamic feature run hook data. */
	run_data = ast_alloca(len_data);
	run_data->app_args_offset = len_args ? len_name : 0;
	run_data->moh_offset = len_moh ? len_name + len_args : 0;
	run_data->feature_offset = len_name + len_args + len_moh;
	run_data->activated_offset = len_name + len_args + len_moh + len_feature;
	strcpy(run_data->app_name, pvt->app_name);/* Safe */
	if (len_args) {
		strcpy(&run_data->app_name[run_data->app_args_offset],
			&pvt->app_name[pvt->app_args_offset]);/* Safe */
	}
	if (len_moh) {
		strcpy(&run_data->app_name[run_data->moh_offset],
			&pvt->app_name[pvt->moh_offset]);/* Safe */
	}
	strcpy(&run_data->app_name[run_data->feature_offset],
		&pvt->app_name[pvt->feature_offset]);/* Safe */
	strcpy(&run_data->app_name[run_data->activated_offset], activated_name);/* Safe */

	if (ast_test_flag(pvt, AST_FEATURE_FLAG_ONPEER)) {
		ast_bridge_channel_write_callback(bridge_channel,
			AST_BRIDGE_CHANNEL_CB_OPTION_MEDIA,
			dynamic_dtmf_hook_callback, run_data, len_data);
	} else {
		dynamic_dtmf_hook_callback(bridge_channel, run_data, len_data);
	}
	return 0;
}

/*!
 * \internal
 * \brief Add a dynamic DTMF feature hook to the bridge features.
 * \since 12.0.0
 *
 * \param features Bridge features to setup.
 * \param flags Which side of bridge to run app (AST_FEATURE_FLAG_ONSELF/AST_FEATURE_FLAG_ONPEER).
 * \param dtmf DTMF trigger sequence.
 * \param feature_name Name of the dynamic feature.
 * \param app_name Dialplan application name to run.
 * \param app_args Dialplan application arguments. (Empty or NULL if no arguments)
 * \param moh_class MOH class to play to peer. (Empty or NULL if no MOH played)
 *
 * \retval 0 on success.
 * \retval -1 on error.
 */
static int dynamic_dtmf_hook_add(struct ast_bridge_features *features, unsigned int flags, const char *dtmf, const char *feature_name, const char *app_name, const char *app_args, const char *moh_class)
{
	struct dynamic_dtmf_hook_data *hook_data;
	size_t len_name = strlen(app_name) + 1;
	size_t len_args = ast_strlen_zero(app_args) ? 0 : strlen(app_args) + 1;
	size_t len_moh = ast_strlen_zero(moh_class) ? 0 : strlen(moh_class) + 1;
	size_t len_feature = strlen(feature_name) + 1;
	size_t len_data = sizeof(*hook_data) + len_name + len_args + len_moh + len_feature;
	int res;

	/* Fill in application run hook data. */
	hook_data = ast_malloc(len_data);
	if (!hook_data) {
		return -1;
	}
	hook_data->flags = flags;
	hook_data->app_args_offset = len_args ? len_name : 0;
	hook_data->moh_offset = len_moh ? len_name + len_args : 0;
	hook_data->feature_offset = len_name + len_args + len_moh;
	strcpy(hook_data->app_name, app_name);/* Safe */
	if (len_args) {
		strcpy(&hook_data->app_name[hook_data->app_args_offset], app_args);/* Safe */
	}
	if (len_moh) {
		strcpy(&hook_data->app_name[hook_data->moh_offset], moh_class);/* Safe */
	}
	strcpy(&hook_data->app_name[hook_data->feature_offset], feature_name);/* Safe */

	res = ast_bridge_dtmf_hook(features, dtmf, dynamic_dtmf_hook_trip, hook_data,
		ast_free_ptr,
		AST_BRIDGE_HOOK_REMOVE_ON_PULL | AST_BRIDGE_HOOK_REMOVE_ON_PERSONALITY_CHANGE);
	if (res) {
		ast_free(hook_data);
	}
	return res;
}

static int setup_dynamic_feature(void *obj, void *arg, void *data, int flags)
{
	struct ast_applicationmap_item *item = obj;
	struct ast_bridge_features *features = arg;
	int *res = data;

	*res |= dynamic_dtmf_hook_add(features,
		item->activate_on_self ? AST_FEATURE_FLAG_ONSELF : AST_FEATURE_FLAG_ONPEER,
		item->dtmf, item->name, item->app, item->app_data, item->moh_class);

	return 0;
}

/*!
 * \internal
 * \brief Setup bridge dynamic features.
 * \since 12.0.0
 *
 * \param features Bridge features to setup.
 * \param chan Get features from this channel.
 *
 * \retval 0 on success.
 * \retval -1 on error.
 */
static int setup_bridge_features_dynamic(struct ast_bridge_features *features, struct ast_channel *chan)
{
	struct ao2_container *applicationmap;
	int res = 0;

	ast_channel_lock(chan);
	applicationmap = ast_get_chan_applicationmap(chan);
	ast_channel_unlock(chan);
	if (applicationmap) {
		ao2_callback_data(applicationmap, 0, setup_dynamic_feature, features, &res);
		ao2_ref(applicationmap, -1);
	}

	return res;
}

/*!
 * \internal
 * \brief Setup DTMF feature hooks using the channel features datastore property.
 * \since 12.0.0
 *
 * \param bridge_channel What to setup DTMF features on.
 *
 * \retval 0 on success.
 * \retval -1 on error.
 */
static int bridge_basic_setup_features(struct ast_bridge_channel *bridge_channel)
{
	int res = 0;

	res |= setup_bridge_features_builtin(bridge_channel->features, bridge_channel->chan);
	res |= setup_bridge_features_dynamic(bridge_channel->features, bridge_channel->chan);

	return res;
}

static int add_normal_hooks(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
{
	return ast_bridge_hangup_hook(bridge_channel->features, basic_hangup_hook,
			NULL, NULL, AST_BRIDGE_HOOK_REMOVE_ON_PULL)
		|| bridge_basic_setup_features(bridge_channel);
}

/*!
 * \internal
 * \brief ast_bridge basic push method.
 * \since 12.0.0
 *
 * \param self Bridge to operate upon.
 * \param bridge_channel Bridge channel to push.
 * \param swap Bridge channel to swap places with if not NULL.
 *
 * \note On entry, self is already locked.
 *
 * \retval 0 on success
 * \retval -1 on failure
 */
static int bridge_personality_normal_push(struct ast_bridge *self, struct ast_bridge_channel *bridge_channel, struct ast_bridge_channel *swap)
{
	if (add_normal_hooks(self, bridge_channel)) {
		return -1;
	}

	return 0;
}

static int bridge_basic_push(struct ast_bridge *self, struct ast_bridge_channel *bridge_channel, struct ast_bridge_channel *swap)
{
	struct bridge_basic_personality *personality = self->personality;

	ast_assert(personality != NULL);

	if (personality->details[personality->current].v_table->push
		&& personality->details[personality->current].v_table->push(self, bridge_channel, swap)) {
		return -1;
	}

	ast_bridge_channel_update_linkedids(bridge_channel, swap);
	ast_bridge_channel_update_accountcodes(bridge_channel, swap);

	return ast_bridge_base_v_table.push(self, bridge_channel, swap);
}

static void bridge_basic_pull(struct ast_bridge *self, struct ast_bridge_channel *bridge_channel)
{
	struct bridge_basic_personality *personality = self->personality;

	ast_assert(personality != NULL);

	if (personality->details[personality->current].v_table->pull) {
		personality->details[personality->current].v_table->pull(self, bridge_channel);
	}

	ast_bridge_channel_update_accountcodes(NULL, bridge_channel);

	ast_bridge_base_v_table.pull(self, bridge_channel);
}

static void bridge_basic_destroy(struct ast_bridge *self)
{
	struct bridge_basic_personality *personality = self->personality;

	ao2_cleanup(personality);

	ast_bridge_base_v_table.destroy(self);
}

/*!
 * \brief Remove appropriate hooks when basic bridge personality changes
 *
 * Hooks that have the AST_BRIDGE_HOOK_REMOVE_ON_PERSONALITY_CHANGE flag
 * set will be removed from all bridge channels in the bridge.
 *
 * \param bridge Basic bridge undergoing personality change
 */
static void remove_hooks_on_personality_change(struct ast_bridge *bridge)
{
	struct ast_bridge_channel *iter;

	AST_LIST_TRAVERSE(&bridge->channels, iter, entry) {
		SCOPED_LOCK(lock, iter, ast_bridge_channel_lock, ast_bridge_channel_unlock);
		ast_bridge_features_remove(iter->features, AST_BRIDGE_HOOK_REMOVE_ON_PERSONALITY_CHANGE);
	}
}

/*!
 * \brief Attended transfer superstates.
 *
 * An attended transfer's progress is facilitated by a state machine.
 * The individual states of the state machine fall into the realm of
 * one of two superstates.
 */
enum attended_transfer_superstate {
	/*!
	 * \brief Transfer superstate
	 *
	 * The attended transfer state machine begins in this superstate. The
	 * goal of this state is for a transferer channel to facilitate a
	 * transfer from a transferee to a transfer target.
	 *
	 * There are two bridges used in this superstate. The transferee bridge is
	 * the bridge that the transferer and transferee channels originally
	 * communicate in, and the target bridge is the bridge where the transfer
	 * target is being dialed.
	 *
	 * The transferer channel is capable of moving between the bridges using
	 * the DTMF swap sequence.
	 */
	SUPERSTATE_TRANSFER,
	/*!
	 * \brief Recall superstate
	 *
	 * The attended transfer state machine moves to this superstate if
	 * atxferdropcall is set to "no" and the transferer channel hangs up
	 * during a transfer. The goal in this superstate is to call back either
	 * the transfer target or transferer and rebridge with the transferee
	 * channel(s).
	 *
	 * In this superstate, there is only a single bridge used, the original
	 * transferee bridge. Rather than distinguishing between a transferer
	 * and transfer target, all outbound calls are toward a "recall_target"
	 * channel.
	 */
	SUPERSTATE_RECALL,
};

/*!
 * The states in the attended transfer state machine.
 */
enum attended_transfer_state {
	/*!
	 * \brief Calling Target state
	 *
	 * This state describes the initial state of a transfer. The transferer
	 * waits in the transfer target's bridge for the transfer target to answer.
	 *
	 * Superstate: Transfer
	 *
	 * Preconditions:
	 * 1) Transfer target is RINGING
	 * 2) Transferer is in transferee bridge
	 * 3) Transferee is on hold
	 *
	 * Transitions to TRANSFER_CALLING_TARGET:
	 * 1) This is the initial state for an attended transfer.
	 * 2) TRANSFER_HESITANT: Transferer presses DTMF swap sequence
	 *
	 * State operation:
	 * The transferer is moved from the transferee bridge into the transfer
	 * target bridge.
	 *
	 * Transitions from TRANSFER_CALLING_TARGET:
	 * 1) TRANSFER_FAIL: Transferee hangs up.
	 * 2) TRANSFER_BLOND: Transferer hangs up or presses DTMF swap sequence
	 * and configured atxferdropcall setting is yes.
	 * 3) TRANSFER_BLOND_NONFINAL: Transferer hangs up or presses DTMF swap
	 * sequence and configured atxferdroppcall setting is no.
	 * 4) TRANSFER_CONSULTING: Transfer target answers the call.
	 * 5) TRANSFER_REBRIDGE: Transfer target hangs up, call to transfer target
	 * times out, or transferer presses DTMF abort sequence.
	 * 6) TRANSFER_THREEWAY: Transferer presses DTMF threeway sequence.
	 * 7) TRANSFER_HESITANT: Transferer presses DTMF swap sequence.
	 */
	TRANSFER_CALLING_TARGET,
	/*!
	 * \brief Hesitant state
	 *
	 * This state only arises if when waiting for the transfer target to
	 * answer, the transferer presses the DTMF swap sequence. This will
	 * cause the transferer to be rebridged with the transferee temporarily.
	 *
	 * Superstate: Transfer
	 *
	 * Preconditions:
	 * 1) Transfer target is in ringing state
	 * 2) Transferer is in transfer target bridge
	 * 3) Transferee is on hold
	 *
	 * Transitions to TRANSFER_HESITANT:
	 * 1) TRANSFER_CALLING_TARGET: Transferer presses DTMF swap sequence.
	 *
	 * State operation:
	 * The transferer is moved from the transfer target bridge into the
	 * transferee bridge, and the transferee is taken off hold.
	 *
	 * Transitions from TRANSFER_HESITANT:
	 * 1) TRANSFER_FAIL: Transferee hangs up
	 * 2) TRANSFER_BLOND: Transferer hangs up or presses DTMF swap sequence
	 * and configured atxferdropcall setting is yes.
	 * 3) TRANSFER_BLOND_NONFINAL: Transferer hangs up or presses DTMF swap
	 * sequence and configured atxferdroppcall setting is no.
	 * 4) TRANSFER_DOUBLECHECKING: Transfer target answers the call
	 * 5) TRANSFER_RESUME: Transfer target hangs up, call to transfer target
	 * times out, or transferer presses DTMF abort sequence.
	 * 6) TRANSFER_THREEWAY: Transferer presses DTMF threeway sequence.
	 * 7) TRANSFER_CALLING_TARGET: Transferer presses DTMF swap sequence.
	 */
	TRANSFER_HESITANT,
	/*!
	 * \brief Rebridge state
	 *
	 * This is a terminal state that indicates that the transferer needs
	 * to move back to the transferee's bridge. This is a failed attended
	 * transfer result.
	 *
	 * Superstate: Transfer
	 *
	 * Preconditions:
	 * 1) Transferer is in transfer target bridge
	 * 2) Transferee is on hold
	 *
	 * Transitions to TRANSFER_REBRIDGE:
	 * 1) TRANSFER_CALLING_TARGET: Transfer target hangs up, call to transfer target
	 * times out, or transferer presses DTMF abort sequence.
	 * 2) TRANSFER_STATE_CONSULTING: Transfer target hangs up, or transferer presses
	 * DTMF abort sequence.
	 *
	 * State operation:
	 * The transferer channel is moved from the transfer target bridge to the
	 * transferee bridge. The transferee is taken off hold. A stasis transfer
	 * message is published indicating a failed attended transfer.
	 *
	 * Transitions from TRANSFER_REBRIDGE:
	 * None
	 */
	TRANSFER_REBRIDGE,
	/*!
	 * \brief Resume state
	 *
	 * This is a terminal state that indicates that the party bridged with the
	 * transferee is the final party to be bridged with that transferee. This state
	 * may come about due to a successful recall or due to a failed transfer.
	 *
	 * Superstate: Transfer or Recall
	 *
	 * Preconditions:
	 * In Transfer Superstate:
	 * 1) Transferer is in transferee bridge
	 * 2) Transferee is not on hold
	 * In Recall Superstate:
	 * 1) The recall target is in the transferee bridge
	 * 2) Transferee is not on hold
	 *
	 * Transitions to TRANSFER_RESUME:
	 * TRANSFER_HESITANT: Transfer target hangs up, call to transfer target times out,
	 * or transferer presses DTMF abort sequence.
	 * TRANSFER_DOUBLECHECKING: Transfer target hangs up or transferer presses DTMF
	 * abort sequence.
	 * TRANSFER_BLOND_NONFINAL: Recall target answers
	 * TRANSFER_RECALLING: Recall target answers
	 * TRANSFER_RETRANSFER: Recall target answers
	 *
	 * State operations:
	 * None
	 *
	 * Transitions from TRANSFER_RESUME:
	 * None
	 */
	TRANSFER_RESUME,
	/*!
	 * \brief Threeway state
	 *
	 * This state results when the transferer wishes to have all parties involved
	 * in a transfer to be in the same bridge together.
	 *
	 * Superstate: Transfer
	 *
	 * Preconditions:
	 * 1) Transfer target state is either RINGING or UP
	 * 2) Transferer is in either bridge
	 * 3) Transferee is not on hold
	 *
	 * Transitions to TRANSFER_THREEWAY:
	 * 1) TRANSFER_CALLING_TARGET: Transferer presses DTMF threeway sequence.
	 * 2) TRANSFER_HESITANT: Transferer presses DTMF threeway sequence.
	 * 3) TRANSFER_CONSULTING: Transferer presses DTMF threeway sequence.
	 * 4) TRANSFER_DOUBLECHECKING: Transferer presses DTMF threeway sequence.
	 *
	 * State operation:
	 * The transfer target bridge is merged into the transferee bridge.
	 *
	 * Transitions from TRANSFER_THREEWAY:
	 * None.
	 */
	TRANSFER_THREEWAY,
	/*!
	 * \brief Consulting state
	 *
	 * This state describes the case where the transferer and transfer target
	 * are able to converse in the transfer target's bridge prior to completing
	 * the transfer.
	 *
	 * Superstate: Transfer
	 *
	 * Preconditions:
	 * 1) Transfer target is UP
	 * 2) Transferer is in target bridge
	 * 3) Transferee is on hold
	 *
	 * Transitions to TRANSFER_CONSULTING:
	 * 1) TRANSFER_CALLING_TARGET: Transfer target answers.
	 * 2) TRANSFER_DOUBLECHECKING: Transferer presses DTMF swap sequence.
	 *
	 * State operations:
	 * None.
	 *
	 * Transitions from TRANSFER_CONSULTING:
	 * TRANSFER_COMPLETE: Transferer hangs up or transferer presses DTMF complete sequence.
	 * TRANSFER_REBRIDGE: Transfer target hangs up or transferer presses DTMF abort sequence.
	 * TRANSFER_THREEWAY: Transferer presses DTMF threeway sequence.
	 * TRANSFER_DOUBLECHECKING: Transferer presses DTMF swap sequence.
	 */
	TRANSFER_CONSULTING,
	/*!
	 * \brief Double-checking state
	 *
	 * This state describes the case where the transferer and transferee are
	 * able to converse in the transferee's bridge prior to completing the transfer. The
	 * difference between this and TRANSFER_HESITANT is that the transfer target is
	 * UP in this case.
	 *
	 * Superstate: Transfer
	 *
	 * Preconditions:
	 * 1) Transfer target is UP and on hold
	 * 2) Transferer is in transferee bridge
	 * 3) Transferee is off hold
	 *
	 * Transitions to TRANSFER_DOUBLECHECKING:
	 * 1) TRANSFER_HESITANT: Transfer target answers.
	 * 2) TRANSFER_CONSULTING: Transferer presses DTMF swap sequence.
	 *
	 * State operations:
	 * None.
	 *
	 * Transitions from TRANSFER_DOUBLECHECKING:
	 * 1) TRANSFER_FAIL: Transferee hangs up.
	 * 2) TRANSFER_COMPLETE: Transferer hangs up or presses DTMF complete sequence.
	 * 3) TRANSFER_RESUME: Transfer target hangs up or transferer presses DTMF abort sequence.
	 * 4) TRANSFER_THREEWAY: Transferer presses DTMF threeway sequence.
	 * 5) TRANSFER_CONSULTING: Transferer presses the DTMF swap sequence.
	 */
	TRANSFER_DOUBLECHECKING,
	/*!
	 * \brief Complete state
	 *
	 * This is a terminal state where a transferer has successfully completed an attended
	 * transfer. This state's goal is to get the transfer target and transferee into
	 * the same bridge and the transferer off the call.
	 *
	 * Superstate: Transfer
	 *
	 * Preconditions:
	 * 1) Transfer target is UP and off hold.