channel: Add ast_read_stream function for reading frames from all streams.

[asterisk/asterisk.git] / main / channel.c

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@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 Channel Management
 *
 * \author Mark Spencer <markster@digium.com>
 */

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

#include "asterisk.h"

#include "asterisk/_private.h"

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

#include "asterisk/paths.h"     /* use ast_config_AST_SYSTEM_NAME */

#include "asterisk/pbx.h"
#include "asterisk/frame.h"
#include "asterisk/mod_format.h"
#include "asterisk/sched.h"
#include "asterisk/channel.h"
#include "asterisk/musiconhold.h"
#include "asterisk/say.h"
#include "asterisk/file.h"
#include "asterisk/cli.h"
#include "asterisk/translate.h"
#include "asterisk/manager.h"
#include "asterisk/chanvars.h"
#include "asterisk/linkedlists.h"
#include "asterisk/indications.h"
#include "asterisk/causes.h"
#include "asterisk/callerid.h"
#include "asterisk/utils.h"
#include "asterisk/lock.h"
#include "asterisk/app.h"
#include "asterisk/transcap.h"
#include "asterisk/devicestate.h"
#include "asterisk/threadstorage.h"
#include "asterisk/slinfactory.h"
#include "asterisk/audiohook.h"
#include "asterisk/framehook.h"
#include "asterisk/timing.h"
#include "asterisk/autochan.h"
#include "asterisk/stringfields.h"
#include "asterisk/global_datastores.h"
#include "asterisk/data.h"
#include "asterisk/channel_internal.h"
#include "asterisk/features.h"
#include "asterisk/bridge.h"
#include "asterisk/test.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/max_forwards.h"
#include "asterisk/stream.h"

/*** DOCUMENTATION
 ***/

#ifdef HAVE_EPOLL
#include <sys/epoll.h>
#endif

#if defined(KEEP_TILL_CHANNEL_PARTY_NUMBER_INFO_NEEDED)
#if defined(HAVE_PRI)
#include "libpri.h"
#endif  /* defined(HAVE_PRI) */
#endif  /* defined(KEEP_TILL_CHANNEL_PARTY_NUMBER_INFO_NEEDED) */

struct ast_epoll_data {
        struct ast_channel *chan;
        int which;
};

/* uncomment if you have problems with 'monitoring' synchronized files */
#if 0
#define MONITOR_CONSTANT_DELAY
#define MONITOR_DELAY   150 * 8         /*!< 150 ms of MONITORING DELAY */
#endif

static int chancount;

unsigned long global_fin, global_fout;

AST_THREADSTORAGE(state2str_threadbuf);
#define STATE2STR_BUFSIZE   32

/*! Default amount of time to use when emulating a digit as a begin and end
 *  100ms */
#define AST_DEFAULT_EMULATE_DTMF_DURATION 100

#define DEFAULT_AMA_FLAGS AST_AMA_DOCUMENTATION

/*! Minimum amount of time between the end of the last digit and the beginning
 *  of a new one - 45ms */
#define AST_MIN_DTMF_GAP 45

/*! \brief List of channel drivers */
struct chanlist {
        const struct ast_channel_tech *tech;
        AST_LIST_ENTRY(chanlist) list;
};

/*! \brief the list of registered channel types */
static AST_RWLIST_HEAD_STATIC(backends, chanlist);

#ifdef LOW_MEMORY
#define NUM_CHANNEL_BUCKETS 61
#else
#define NUM_CHANNEL_BUCKETS 1567
#endif

/*! \brief All active channels on the system */
static struct ao2_container *channels;

/*! \brief map AST_CAUSE's to readable string representations
 *
 * \ref causes.h
*/
struct causes_map {
        int cause;
        const char *name;
        const char *desc;
};

static const struct causes_map causes[] = {
        { AST_CAUSE_UNALLOCATED, "UNALLOCATED", "Unallocated (unassigned) number" },
        { AST_CAUSE_NO_ROUTE_TRANSIT_NET, "NO_ROUTE_TRANSIT_NET", "No route to specified transmit network" },
        { AST_CAUSE_NO_ROUTE_DESTINATION, "NO_ROUTE_DESTINATION", "No route to destination" },
        { AST_CAUSE_MISDIALLED_TRUNK_PREFIX, "MISDIALLED_TRUNK_PREFIX", "Misdialed trunk prefix" },
        { AST_CAUSE_CHANNEL_UNACCEPTABLE, "CHANNEL_UNACCEPTABLE", "Channel unacceptable" },
        { AST_CAUSE_CALL_AWARDED_DELIVERED, "CALL_AWARDED_DELIVERED", "Call awarded and being delivered in an established channel" },
        { AST_CAUSE_PRE_EMPTED, "PRE_EMPTED", "Pre-empted" },
        { AST_CAUSE_NUMBER_PORTED_NOT_HERE, "NUMBER_PORTED_NOT_HERE", "Number ported elsewhere" },
        { AST_CAUSE_NORMAL_CLEARING, "NORMAL_CLEARING", "Normal Clearing" },
        { AST_CAUSE_USER_BUSY, "USER_BUSY", "User busy" },
        { AST_CAUSE_NO_USER_RESPONSE, "NO_USER_RESPONSE", "No user responding" },
        { AST_CAUSE_NO_ANSWER, "NO_ANSWER", "User alerting, no answer" },
        { AST_CAUSE_SUBSCRIBER_ABSENT, "SUBSCRIBER_ABSENT", "Subscriber absent" },
        { AST_CAUSE_CALL_REJECTED, "CALL_REJECTED", "Call Rejected" },
        { AST_CAUSE_NUMBER_CHANGED, "NUMBER_CHANGED", "Number changed" },
        { AST_CAUSE_REDIRECTED_TO_NEW_DESTINATION, "REDIRECTED_TO_NEW_DESTINATION", "Redirected to new destination" },
        { AST_CAUSE_ANSWERED_ELSEWHERE, "ANSWERED_ELSEWHERE", "Answered elsewhere" },
        { AST_CAUSE_DESTINATION_OUT_OF_ORDER, "DESTINATION_OUT_OF_ORDER", "Destination out of order" },
        { AST_CAUSE_INVALID_NUMBER_FORMAT, "INVALID_NUMBER_FORMAT", "Invalid number format" },
        { AST_CAUSE_FACILITY_REJECTED, "FACILITY_REJECTED", "Facility rejected" },
        { AST_CAUSE_RESPONSE_TO_STATUS_ENQUIRY, "RESPONSE_TO_STATUS_ENQUIRY", "Response to STATus ENQuiry" },
        { AST_CAUSE_NORMAL_UNSPECIFIED, "NORMAL_UNSPECIFIED", "Normal, unspecified" },
        { AST_CAUSE_NORMAL_CIRCUIT_CONGESTION, "NORMAL_CIRCUIT_CONGESTION", "Circuit/channel congestion" },
        { AST_CAUSE_NETWORK_OUT_OF_ORDER, "NETWORK_OUT_OF_ORDER", "Network out of order" },
        { AST_CAUSE_NORMAL_TEMPORARY_FAILURE, "NORMAL_TEMPORARY_FAILURE", "Temporary failure" },
        { AST_CAUSE_SWITCH_CONGESTION, "SWITCH_CONGESTION", "Switching equipment congestion" },
        { AST_CAUSE_ACCESS_INFO_DISCARDED, "ACCESS_INFO_DISCARDED", "Access information discarded" },
        { AST_CAUSE_REQUESTED_CHAN_UNAVAIL, "REQUESTED_CHAN_UNAVAIL", "Requested channel not available" },
        { AST_CAUSE_FACILITY_NOT_SUBSCRIBED, "FACILITY_NOT_SUBSCRIBED", "Facility not subscribed" },
        { AST_CAUSE_OUTGOING_CALL_BARRED, "OUTGOING_CALL_BARRED", "Outgoing call barred" },
        { AST_CAUSE_INCOMING_CALL_BARRED, "INCOMING_CALL_BARRED", "Incoming call barred" },
        { AST_CAUSE_BEARERCAPABILITY_NOTAUTH, "BEARERCAPABILITY_NOTAUTH", "Bearer capability not authorized" },
        { AST_CAUSE_BEARERCAPABILITY_NOTAVAIL, "BEARERCAPABILITY_NOTAVAIL", "Bearer capability not available" },
        { AST_CAUSE_BEARERCAPABILITY_NOTIMPL, "BEARERCAPABILITY_NOTIMPL", "Bearer capability not implemented" },
        { AST_CAUSE_CHAN_NOT_IMPLEMENTED, "CHAN_NOT_IMPLEMENTED", "Channel not implemented" },
        { AST_CAUSE_FACILITY_NOT_IMPLEMENTED, "FACILITY_NOT_IMPLEMENTED", "Facility not implemented" },
        { AST_CAUSE_INVALID_CALL_REFERENCE, "INVALID_CALL_REFERENCE", "Invalid call reference value" },
        { AST_CAUSE_INCOMPATIBLE_DESTINATION, "INCOMPATIBLE_DESTINATION", "Incompatible destination" },
        { AST_CAUSE_INVALID_MSG_UNSPECIFIED, "INVALID_MSG_UNSPECIFIED", "Invalid message unspecified" },
        { AST_CAUSE_MANDATORY_IE_MISSING, "MANDATORY_IE_MISSING", "Mandatory information element is missing" },
        { AST_CAUSE_MESSAGE_TYPE_NONEXIST, "MESSAGE_TYPE_NONEXIST", "Message type nonexist." },
        { AST_CAUSE_WRONG_MESSAGE, "WRONG_MESSAGE", "Wrong message" },
        { AST_CAUSE_IE_NONEXIST, "IE_NONEXIST", "Info. element nonexist or not implemented" },
        { AST_CAUSE_INVALID_IE_CONTENTS, "INVALID_IE_CONTENTS", "Invalid information element contents" },
        { AST_CAUSE_WRONG_CALL_STATE, "WRONG_CALL_STATE", "Message not compatible with call state" },
        { AST_CAUSE_RECOVERY_ON_TIMER_EXPIRE, "RECOVERY_ON_TIMER_EXPIRE", "Recover on timer expiry" },
        { AST_CAUSE_MANDATORY_IE_LENGTH_ERROR, "MANDATORY_IE_LENGTH_ERROR", "Mandatory IE length error" },
        { AST_CAUSE_PROTOCOL_ERROR, "PROTOCOL_ERROR", "Protocol error, unspecified" },
        { AST_CAUSE_INTERWORKING, "INTERWORKING", "Interworking, unspecified" },
};

struct ast_variable *ast_channeltype_list(void)
{
        struct chanlist *cl;
        struct ast_variable *var = NULL, *prev = NULL;

        AST_RWLIST_RDLOCK(&backends);
        AST_RWLIST_TRAVERSE(&backends, cl, list) {
                if (prev)  {
                        if ((prev->next = ast_variable_new(cl->tech->type, cl->tech->description, "")))
                                prev = prev->next;
                } else {
                        var = ast_variable_new(cl->tech->type, cl->tech->description, "");
                        prev = var;
                }
        }
        AST_RWLIST_UNLOCK(&backends);

        return var;
}

#if defined(KEEP_TILL_CHANNEL_PARTY_NUMBER_INFO_NEEDED)
static const char *party_number_ton2str(int ton)
{
#if defined(HAVE_PRI)
        switch ((ton >> 4) & 0x07) {
        case PRI_TON_INTERNATIONAL:
                return "International";
        case PRI_TON_NATIONAL:
                return "National";
        case PRI_TON_NET_SPECIFIC:
                return "Network Specific";
        case PRI_TON_SUBSCRIBER:
                return "Subscriber";
        case PRI_TON_ABBREVIATED:
                return "Abbreviated";
        case PRI_TON_RESERVED:
                return "Reserved";
        case PRI_TON_UNKNOWN:
        default:
                break;
        }
#endif  /* defined(HAVE_PRI) */
        return "Unknown";
}
#endif  /* defined(KEEP_TILL_CHANNEL_PARTY_NUMBER_INFO_NEEDED) */

#if defined(KEEP_TILL_CHANNEL_PARTY_NUMBER_INFO_NEEDED)
static const char *party_number_plan2str(int plan)
{
#if defined(HAVE_PRI)
        switch (plan & 0x0F) {
        default:
        case PRI_NPI_UNKNOWN:
                break;
        case PRI_NPI_E163_E164:
                return "Public (E.163/E.164)";
        case PRI_NPI_X121:
                return "Data (X.121)";
        case PRI_NPI_F69:
                return "Telex (F.69)";
        case PRI_NPI_NATIONAL:
                return "National Standard";
        case PRI_NPI_PRIVATE:
                return "Private";
        case PRI_NPI_RESERVED:
                return "Reserved";
        }
#endif  /* defined(HAVE_PRI) */
        return "Unknown";
}
#endif  /* defined(KEEP_TILL_CHANNEL_PARTY_NUMBER_INFO_NEEDED) */

/*! \brief Show channel types - CLI command */
static char *handle_cli_core_show_channeltypes(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
#define FORMAT  "%-15.15s  %-40.40s %-13.13s %-13.13s %-13.13s %-13.13s\n"
        struct chanlist *cl;
        int count_chan = 0;

        switch (cmd) {
        case CLI_INIT:
                e->command = "core show channeltypes";
                e->usage =
                        "Usage: core show channeltypes\n"
                        "       Lists available channel types registered in your\n"
                        "       Asterisk server.\n";
                return NULL;
        case CLI_GENERATE:
                return NULL;
        }

        if (a->argc != 3)
                return CLI_SHOWUSAGE;

        ast_cli(a->fd, FORMAT, "Type", "Description", "Devicestate", "Presencestate", "Indications", "Transfer");
        ast_cli(a->fd, FORMAT, "-------------", "-------------", "-------------", "-------------", "-------------", "-------------");

        AST_RWLIST_RDLOCK(&backends);
        AST_RWLIST_TRAVERSE(&backends, cl, list) {
                ast_cli(a->fd, FORMAT, cl->tech->type, cl->tech->description,
                        (cl->tech->devicestate) ? "yes" : "no",
                        (cl->tech->presencestate) ? "yes" : "no",
                        (cl->tech->indicate) ? "yes" : "no",
                        (cl->tech->transfer) ? "yes" : "no");
                count_chan++;
        }
        AST_RWLIST_UNLOCK(&backends);

        ast_cli(a->fd, "----------\n%d channel drivers registered.\n", count_chan);

        return CLI_SUCCESS;

#undef FORMAT
}

static char *complete_channeltypes(struct ast_cli_args *a)
{
        struct chanlist *cl;
        int which = 0;
        int wordlen;
        char *ret = NULL;

        if (a->pos != 3)
                return NULL;

        wordlen = strlen(a->word);

        AST_RWLIST_RDLOCK(&backends);
        AST_RWLIST_TRAVERSE(&backends, cl, list) {
                if (!strncasecmp(a->word, cl->tech->type, wordlen) && ++which > a->n) {
                        ret = ast_strdup(cl->tech->type);
                        break;
                }
        }
        AST_RWLIST_UNLOCK(&backends);

        return ret;
}

/*! \brief Show details about a channel driver - CLI command */
static char *handle_cli_core_show_channeltype(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
        struct chanlist *cl = NULL;
        struct ast_str *codec_buf = ast_str_alloca(AST_FORMAT_CAP_NAMES_LEN);

        switch (cmd) {
        case CLI_INIT:
                e->command = "core show channeltype";
                e->usage =
                        "Usage: core show channeltype <name>\n"
                        "       Show details about the specified channel type, <name>.\n";
                return NULL;
        case CLI_GENERATE:
                return complete_channeltypes(a);
        }

        if (a->argc != 4)
                return CLI_SHOWUSAGE;

        AST_RWLIST_RDLOCK(&backends);

        AST_RWLIST_TRAVERSE(&backends, cl, list) {
                if (!strncasecmp(cl->tech->type, a->argv[3], strlen(cl->tech->type)))
                        break;
        }


        if (!cl) {
                ast_cli(a->fd, "\n%s is not a registered channel driver.\n", a->argv[3]);
                AST_RWLIST_UNLOCK(&backends);
                return CLI_FAILURE;
        }

        ast_cli(a->fd,
                "-- Info about channel driver: %s --\n"
                "  Device State: %s\n"
                "Presence State: %s\n"
                "    Indication: %s\n"
                "     Transfer : %s\n"
                "  Capabilities: %s\n"
                "   Digit Begin: %s\n"
                "     Digit End: %s\n"
                "    Send HTML : %s\n"
                " Image Support: %s\n"
                "  Text Support: %s\n",
                cl->tech->type,
                (cl->tech->devicestate) ? "yes" : "no",
                (cl->tech->presencestate) ? "yes" : "no",
                (cl->tech->indicate) ? "yes" : "no",
                (cl->tech->transfer) ? "yes" : "no",
                ast_format_cap_get_names(cl->tech->capabilities, &codec_buf),
                (cl->tech->send_digit_begin) ? "yes" : "no",
                (cl->tech->send_digit_end) ? "yes" : "no",
                (cl->tech->send_html) ? "yes" : "no",
                (cl->tech->send_image) ? "yes" : "no",
                (cl->tech->send_text) ? "yes" : "no"

        );

        AST_RWLIST_UNLOCK(&backends);

        return CLI_SUCCESS;
}

static struct ast_cli_entry cli_channel[] = {
        AST_CLI_DEFINE(handle_cli_core_show_channeltypes, "List available channel types"),
        AST_CLI_DEFINE(handle_cli_core_show_channeltype,  "Give more details on that channel type")
};

static struct ast_frame *kill_read(struct ast_channel *chan)
{
        /* Hangup channel. */
        return NULL;
}

static struct ast_frame *kill_exception(struct ast_channel *chan)
{
        /* Hangup channel. */
        return NULL;
}

static int kill_write(struct ast_channel *chan, struct ast_frame *frame)
{
        /* Hangup channel. */
        return -1;
}

static int kill_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
{
        /* No problem fixing up the channel. */
        return 0;
}

static int kill_hangup(struct ast_channel *chan)
{
        ast_channel_tech_pvt_set(chan, NULL);
        return 0;
}

/*!
 * \brief Kill the channel channel driver technology descriptor.
 *
 * \details
 * The purpose of this channel technology is to encourage the
 * channel to hangup as quickly as possible.
 *
 * \note Used by DTMF atxfer and zombie channels.
 */
const struct ast_channel_tech ast_kill_tech = {
        .type = "Kill",
        .description = "Kill channel (should not see this)",
        .read = kill_read,
        .exception = kill_exception,
        .write = kill_write,
        .fixup = kill_fixup,
        .hangup = kill_hangup,
};

/*! \brief Checks to see if a channel is needing hang up */
int ast_check_hangup(struct ast_channel *chan)
{
        if (ast_channel_softhangup_internal_flag(chan))         /* yes if soft hangup flag set */
                return 1;
        if (ast_tvzero(*ast_channel_whentohangup(chan)))        /* no if no hangup scheduled */
                return 0;
        if (ast_tvdiff_ms(*ast_channel_whentohangup(chan), ast_tvnow()) > 0)            /* no if hangup time has not come yet. */
                return 0;
        ast_debug(4, "Hangup time has come: %" PRIi64 "\n", ast_tvdiff_ms(*ast_channel_whentohangup(chan), ast_tvnow()));
        ast_test_suite_event_notify("HANGUP_TIME", "Channel: %s", ast_channel_name(chan));
        ast_channel_softhangup_internal_flag_add(chan, AST_SOFTHANGUP_TIMEOUT); /* record event */
        return 1;
}

int ast_check_hangup_locked(struct ast_channel *chan)
{
        int res;
        ast_channel_lock(chan);
        res = ast_check_hangup(chan);
        ast_channel_unlock(chan);
        return res;
}

void ast_channel_softhangup_withcause_locked(struct ast_channel *chan, int causecode)
{
        ast_channel_lock(chan);

        if (causecode > 0) {
                ast_debug(1, "Setting hangupcause of channel %s to %d (is %d now)\n",
                        ast_channel_name(chan), causecode, ast_channel_hangupcause(chan));

                ast_channel_hangupcause_set(chan, causecode);
        }

        ast_softhangup_nolock(chan, AST_SOFTHANGUP_EXPLICIT);

        ast_channel_unlock(chan);
}

static int ast_channel_softhangup_cb(void *obj, void *arg, int flags)
{
        struct ast_channel *chan = obj;

        ast_softhangup(chan, AST_SOFTHANGUP_SHUTDOWN);

        return 0;
}

void ast_softhangup_all(void)
{
        ao2_callback(channels, OBJ_NODATA | OBJ_MULTIPLE, ast_channel_softhangup_cb, NULL);
}

/*! \brief returns number of active/allocated channels */
int ast_active_channels(void)
{
        return channels ? ao2_container_count(channels) : 0;
}

int ast_undestroyed_channels(void)
{
        return ast_atomic_fetchadd_int(&chancount, 0);
}

/*! \brief Set when to hangup channel */
void ast_channel_setwhentohangup_tv(struct ast_channel *chan, struct timeval offset)
{
        if (ast_tvzero(offset)) {
                ast_channel_whentohangup_set(chan, &offset);
        } else {
                struct timeval tv = ast_tvadd(offset, ast_tvnow());
                ast_channel_whentohangup_set(chan, &tv);
        }
        ast_queue_frame(chan, &ast_null_frame);
        return;
}

void ast_channel_setwhentohangup(struct ast_channel *chan, time_t offset)
{
        struct timeval when = { offset, };
        ast_channel_setwhentohangup_tv(chan, when);
}

/*! \brief Compare a offset with when to hangup channel */
int ast_channel_cmpwhentohangup_tv(struct ast_channel *chan, struct timeval offset)
{
        struct timeval whentohangup;

        if (ast_tvzero(*ast_channel_whentohangup(chan)))
                return ast_tvzero(offset) ? 0 : -1;

        if (ast_tvzero(offset))
                return 1;

        whentohangup = ast_tvadd(offset, ast_tvnow());

        return ast_tvdiff_ms(whentohangup, *ast_channel_whentohangup(chan));
}

int ast_channel_cmpwhentohangup(struct ast_channel *chan, time_t offset)
{
        struct timeval when = { offset, };
        return ast_channel_cmpwhentohangup_tv(chan, when);
}

/*! \brief Register a new telephony channel in Asterisk */
int ast_channel_register(const struct ast_channel_tech *tech)
{
        struct chanlist *chan;

        AST_RWLIST_WRLOCK(&backends);

        AST_RWLIST_TRAVERSE(&backends, chan, list) {
                if (!strcasecmp(tech->type, chan->tech->type)) {
                        ast_log(LOG_WARNING, "Already have a handler for type '%s'\n", tech->type);
                        AST_RWLIST_UNLOCK(&backends);
                        return -1;
                }
        }

        if (!(chan = ast_calloc(1, sizeof(*chan)))) {
                AST_RWLIST_UNLOCK(&backends);
                return -1;
        }
        chan->tech = tech;
        AST_RWLIST_INSERT_HEAD(&backends, chan, list);

        ast_debug(1, "Registered handler for '%s' (%s)\n", chan->tech->type, chan->tech->description);

        ast_verb(2, "Registered channel type '%s' (%s)\n", chan->tech->type, chan->tech->description);

        AST_RWLIST_UNLOCK(&backends);

        return 0;
}

/*! \brief Unregister channel driver */
void ast_channel_unregister(const struct ast_channel_tech *tech)
{
        struct chanlist *chan;

        ast_debug(1, "Unregistering channel type '%s'\n", tech->type);

        AST_RWLIST_WRLOCK(&backends);

        AST_RWLIST_TRAVERSE_SAFE_BEGIN(&backends, chan, list) {
                if (chan->tech == tech) {
                        AST_LIST_REMOVE_CURRENT(list);
                        ast_free(chan);
                        ast_verb(2, "Unregistered channel type '%s'\n", tech->type);
                        break;
                }
        }
        AST_LIST_TRAVERSE_SAFE_END;

        AST_RWLIST_UNLOCK(&backends);
}

/*! \brief Get handle to channel driver based on name */
const struct ast_channel_tech *ast_get_channel_tech(const char *name)
{
        struct chanlist *chanls;
        const struct ast_channel_tech *ret = NULL;

        AST_RWLIST_RDLOCK(&backends);

        AST_RWLIST_TRAVERSE(&backends, chanls, list) {
                if (!strcasecmp(name, chanls->tech->type)) {
                        ret = chanls->tech;
                        break;
                }
        }

        AST_RWLIST_UNLOCK(&backends);

        return ret;
}

/*! \brief Gives the string form of a given hangup cause */
const char *ast_cause2str(int cause)
{
        int x;

        for (x = 0; x < ARRAY_LEN(causes); x++) {
                if (causes[x].cause == cause)
                        return causes[x].desc;
        }

        return "Unknown";
}

/*! \brief Convert a symbolic hangup cause to number */
int ast_str2cause(const char *name)
{
        int x;

        for (x = 0; x < ARRAY_LEN(causes); x++)
                if (!strncasecmp(causes[x].name, name, strlen(causes[x].name)))
                        return causes[x].cause;

        return -1;
}

static struct stasis_message *create_channel_snapshot_message(struct ast_channel *channel)
{
        RAII_VAR(struct ast_channel_snapshot *, snapshot, NULL, ao2_cleanup);

        if (!ast_channel_snapshot_type()) {
                return NULL;
        }

        ast_channel_lock(channel);
        snapshot = ast_channel_snapshot_create(channel);
        ast_channel_unlock(channel);
        if (!snapshot) {
                return NULL;
        }

        return stasis_message_create(ast_channel_snapshot_type(), snapshot);
}

static void publish_cache_clear(struct ast_channel *chan)
{
        RAII_VAR(struct stasis_message *, message, NULL, ao2_cleanup);
        RAII_VAR(struct stasis_message *, clear_msg, NULL, ao2_cleanup);

        clear_msg = create_channel_snapshot_message(chan);
        if (!clear_msg) {
                return;
        }

        message = stasis_cache_clear_create(clear_msg);
        stasis_publish(ast_channel_topic(chan), message);
}

/*! \brief Gives the string form of a given channel state.
 *
 * \note This function is not reentrant.
 *
 * \param state
 */
const char *ast_state2str(enum ast_channel_state state)
{
        char *buf;

        switch (state) {
        case AST_STATE_DOWN:
                return "Down";
        case AST_STATE_RESERVED:
                return "Rsrvd";
        case AST_STATE_OFFHOOK:
                return "OffHook";
        case AST_STATE_DIALING:
                return "Dialing";
        case AST_STATE_RING:
                return "Ring";
        case AST_STATE_RINGING:
                return "Ringing";
        case AST_STATE_UP:
                return "Up";
        case AST_STATE_BUSY:
                return "Busy";
        case AST_STATE_DIALING_OFFHOOK:
                return "Dialing Offhook";
        case AST_STATE_PRERING:
                return "Pre-ring";
        case AST_STATE_MUTE:
                return "Mute";
        default:
                if (!(buf = ast_threadstorage_get(&state2str_threadbuf, STATE2STR_BUFSIZE)))
                        return "Unknown";
                snprintf(buf, STATE2STR_BUFSIZE, "Unknown (%u)", state);
                return buf;
        }
}

/*! \brief Gives the string form of a given transfer capability */
char *ast_transfercapability2str(int transfercapability)
{
        switch (transfercapability) {
        case AST_TRANS_CAP_SPEECH:
                return "SPEECH";
        case AST_TRANS_CAP_DIGITAL:
                return "DIGITAL";
        case AST_TRANS_CAP_RESTRICTED_DIGITAL:
                return "RESTRICTED_DIGITAL";
        case AST_TRANS_CAP_3_1K_AUDIO:
                return "3K1AUDIO";
        case AST_TRANS_CAP_DIGITAL_W_TONES:
                return "DIGITAL_W_TONES";
        case AST_TRANS_CAP_VIDEO:
                return "VIDEO";
        default:
                return "UNKNOWN";
        }
}

/*! \brief Channel technology used to extract a channel from a running application. The
 * channel created with this technology will be immediately hung up - most external
 * applications won't ever want to see this.
 */
static const struct ast_channel_tech surrogate_tech = {
        .type = "Surrogate",
        .description = "Surrogate channel used to pull channel from an application",
        .properties = AST_CHAN_TP_INTERNAL,
};

static const struct ast_channel_tech null_tech = {
        .type = "NULL",
        .description = "Null channel (should not see this)",
};

static void ast_channel_destructor(void *obj);
static void ast_dummy_channel_destructor(void *obj);
static int ast_channel_by_uniqueid_cb(void *obj, void *arg, void *data, int flags);

static int does_id_conflict(const char *uniqueid)
{
        struct ast_channel *conflict;
        int length = 0;

        if (ast_strlen_zero(uniqueid)) {
                return 0;
        }

        conflict = ast_channel_callback(ast_channel_by_uniqueid_cb, (char *) uniqueid, &length, OBJ_NOLOCK);
        if (conflict) {
                ast_log(LOG_ERROR, "Channel Unique ID '%s' already in use by channel %s(%p)\n",
                        uniqueid, ast_channel_name(conflict), conflict);
                ast_channel_unref(conflict);
                return 1;
        }

        return 0;
}

/*! \brief Create a new channel structure */
static struct ast_channel * attribute_malloc __attribute__((format(printf, 15, 0)))
__ast_channel_alloc_ap(int needqueue, int state, const char *cid_num, const char *cid_name,
                       const char *acctcode, const char *exten, const char *context, const struct ast_assigned_ids *assignedids,
                       const struct ast_channel *requestor, enum ama_flags amaflag, struct ast_endpoint *endpoint,
                       const char *file, int line,
                       const char *function, const char *name_fmt, va_list ap)
{
        struct ast_channel *tmp;
        struct varshead *headp;
        char *tech = "", *tech2 = NULL;
        struct ast_format_cap *nativeformats;
        struct ast_sched_context *schedctx;
        struct ast_timer *timer;
        struct timeval now;
        const struct ast_channel_tech *channel_tech;
        struct ast_stream_topology *topology;

        /* If shutting down, don't allocate any new channels */
        if (ast_shutting_down()) {
                ast_log(LOG_WARNING, "Channel allocation failed: Refusing due to active shutdown\n");
                return NULL;
        }

        tmp = __ast_channel_internal_alloc(ast_channel_destructor, assignedids, requestor,
                file, line, function);
        if (!tmp) {
                /* Channel structure allocation failure. */
                return NULL;
        }

        ast_channel_stage_snapshot(tmp);

        if (!(nativeformats = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT))) {
                /*
                 * Aborting the channel creation.  We do not need to complete staging
                 * the channel snapshot because the channel has not been finalized or
                 * linked into the channels container yet.  Nobody else knows about
                 * this channel nor will anybody ever know about it.
                 */
                return ast_channel_unref(tmp);
        }
        ast_format_cap_append(nativeformats, ast_format_none, 0);
        ast_channel_nativeformats_set(tmp, nativeformats);
        ao2_ref(nativeformats, -1);

        ast_channel_set_rawwriteformat(tmp, ast_format_none);
        ast_channel_set_rawreadformat(tmp, ast_format_none);
        ast_channel_set_writeformat(tmp, ast_format_none);
        ast_channel_set_readformat(tmp, ast_format_none);

        /*
         * Init file descriptors to unopened state so
         * the destructor can know not to close them.
         */
        ast_channel_timingfd_set(tmp, -1);
        ast_channel_internal_alertpipe_clear(tmp);
        ast_channel_internal_fd_clear_all(tmp);

#ifdef HAVE_EPOLL
        ast_channel_epfd_set(tmp, epoll_create(25));
#endif

        if (!(schedctx = ast_sched_context_create())) {
                ast_log(LOG_WARNING, "Channel allocation failed: Unable to create schedule context\n");
                /* See earlier channel creation abort comment above. */
                return ast_channel_unref(tmp);
        }
        ast_channel_sched_set(tmp, schedctx);

        ast_party_dialed_init(ast_channel_dialed(tmp));
        ast_party_caller_init(ast_channel_caller(tmp));
        ast_party_connected_line_init(ast_channel_connected(tmp));
        ast_party_connected_line_init(ast_channel_connected_indicated(tmp));
        ast_party_redirecting_init(ast_channel_redirecting(tmp));

        if (cid_name) {
                ast_channel_caller(tmp)->id.name.valid = 1;
                ast_channel_caller(tmp)->id.name.str = ast_strdup(cid_name);
                if (!ast_channel_caller(tmp)->id.name.str) {
                        /* See earlier channel creation abort comment above. */
                        return ast_channel_unref(tmp);
                }
        }
        if (cid_num) {
                ast_channel_caller(tmp)->id.number.valid = 1;
                ast_channel_caller(tmp)->id.number.str = ast_strdup(cid_num);
                if (!ast_channel_caller(tmp)->id.number.str) {
                        /* See earlier channel creation abort comment above. */
                        return ast_channel_unref(tmp);
                }
        }

        if ((timer = ast_timer_open())) {
                ast_channel_timer_set(tmp, timer);
                if (strcmp(ast_timer_get_name(ast_channel_timer(tmp)), "timerfd")) {
                        needqueue = 0;
                }
                ast_channel_timingfd_set(tmp, ast_timer_fd(ast_channel_timer(tmp)));
        }

        if (needqueue && ast_channel_internal_alertpipe_init(tmp)) {
                /* See earlier channel creation abort comment above. */
                return ast_channel_unref(tmp);
        }

        if (!(topology = ast_stream_topology_alloc())) {
                return ast_channel_unref(tmp);
        }
        ast_channel_internal_set_stream_topology(tmp, topology);

        /* Always watch the alertpipe */
        ast_channel_set_fd(tmp, AST_ALERT_FD, ast_channel_internal_alert_readfd(tmp));
        /* And timing pipe */
        ast_channel_set_fd(tmp, AST_TIMING_FD, ast_channel_timingfd(tmp));

        /* Initial state */
        ast_channel_state_set(tmp, state);
        ast_channel_hold_state_set(tmp, AST_CONTROL_UNHOLD);

        ast_channel_streamid_set(tmp, -1);
        ast_channel_vstreamid_set(tmp, -1);

        ast_channel_fin_set(tmp, global_fin);
        ast_channel_fout_set(tmp, global_fout);

        now = ast_tvnow();
        ast_channel_creationtime_set(tmp, &now);

        ast_channel_internal_setup_topics(tmp);

        if (!ast_strlen_zero(name_fmt)) {
                char *slash, *slash2;
                /* Almost every channel is calling this function, and setting the name via the ast_string_field_build() call.
                 * And they all use slightly different formats for their name string.
                 * This means, to set the name here, we have to accept variable args, and call the string_field_build from here.
                 * This means, that the stringfields must have a routine that takes the va_lists directly, and
                 * uses them to build the string, instead of forming the va_lists internally from the vararg ... list.
                 * This new function was written so this can be accomplished.
                 */
                ast_channel_name_build_va(tmp, name_fmt, ap);
                tech = ast_strdupa(ast_channel_name(tmp));
                if ((slash = strchr(tech, '/'))) {
                        if ((slash2 = strchr(slash + 1, '/'))) {
                                tech2 = slash + 1;
                                *slash2 = '\0';
                        }
                        *slash = '\0';
                }
        } else {
                /*
                 * Start the string with '-' so it becomes an empty string
                 * in the destructor.
                 */
                ast_channel_name_set(tmp, "-**Unknown**");
        }

        if (amaflag != AST_AMA_NONE) {
                ast_channel_amaflags_set(tmp, amaflag);
        } else {
                ast_channel_amaflags_set(tmp, DEFAULT_AMA_FLAGS);
        }

        if (!ast_strlen_zero(acctcode)) {
                ast_channel_accountcode_set(tmp, acctcode);
        }
        ast_channel_language_set(tmp, ast_defaultlanguage);

        ast_channel_context_set(tmp, S_OR(context, "default"));
        ast_channel_exten_set(tmp, S_OR(exten, "s"));
        ast_channel_priority_set(tmp, 1);

        headp = ast_channel_varshead(tmp);
        AST_LIST_HEAD_INIT_NOLOCK(headp);

        ast_pbx_hangup_handler_init(tmp);
        AST_LIST_HEAD_INIT_NOLOCK(ast_channel_datastores(tmp));
        AST_LIST_HEAD_INIT_NOLOCK(ast_channel_autochans(tmp));

        channel_tech = ast_get_channel_tech(tech);
        if (!channel_tech && !ast_strlen_zero(tech2)) {
                channel_tech = ast_get_channel_tech(tech2);
        }
        if (channel_tech) {
                ast_channel_tech_set(tmp, channel_tech);
        } else {
                ast_channel_tech_set(tmp, &null_tech);
        }

        /* You might scream "locking inversion" at seeing this but it is actually perfectly fine.
         * Since the channel was just created nothing can know about it yet or even acquire it.
         */
        ast_channel_lock(tmp);

        ao2_lock(channels);

        if (assignedids && (does_id_conflict(assignedids->uniqueid) || does_id_conflict(assignedids->uniqueid2))) {
                ast_channel_internal_errno_set(AST_CHANNEL_ERROR_ID_EXISTS);
                ao2_unlock(channels);
                ast_channel_unlock(tmp);
                /* See earlier channel creation abort comment above. */
                return ast_channel_unref(tmp);
        }

        /* Finalize and link into the channels container. */
        ast_channel_internal_finalize(tmp);
        ast_atomic_fetchadd_int(&chancount, +1);
        ao2_link_flags(channels, tmp, OBJ_NOLOCK);

        ao2_unlock(channels);

        if (endpoint) {
                ast_endpoint_add_channel(endpoint, tmp);
        }

        /*
         * And now, since the channel structure is built, and has its name, let
         * the world know of its existance
         */
        ast_channel_stage_snapshot_done(tmp);
        return tmp;
}

struct ast_channel *__ast_channel_alloc(int needqueue, int state, const char *cid_num,
                                        const char *cid_name, const char *acctcode,
                                        const char *exten, const char *context, const struct ast_assigned_ids *assignedids,
                                        const struct ast_channel *requestor, enum ama_flags amaflag,
                                        struct ast_endpoint *endpoint,
                                        const char *file, int line, const char *function,
                                        const char *name_fmt, ...)
{
        va_list ap;
        struct ast_channel *result;

        va_start(ap, name_fmt);
        result = __ast_channel_alloc_ap(needqueue, state, cid_num, cid_name, acctcode, exten, context,
                                        assignedids, requestor, amaflag, endpoint, file, line, function, name_fmt, ap);
        va_end(ap);

        return result;
}

/* only do the minimum amount of work needed here to make a channel
 * structure that can be used to expand channel vars */
struct ast_channel *__ast_dummy_channel_alloc(const char *file, int line, const char *function)
{
        struct ast_channel *tmp;
        struct varshead *headp;

        tmp = __ast_channel_internal_alloc(ast_dummy_channel_destructor, NULL, NULL,
                file, line, function);
        if (!tmp) {
                /* Dummy channel structure allocation failure. */
                return NULL;
        }

        ast_pbx_hangup_handler_init(tmp);
        AST_LIST_HEAD_INIT_NOLOCK(ast_channel_datastores(tmp));

        /*
         * Init file descriptors to unopened state just in case
         * autoservice is called on the channel or something tries to
         * read a frame from it.
         */
        ast_channel_timingfd_set(tmp, -1);
        ast_channel_internal_alertpipe_clear(tmp);
        ast_channel_internal_fd_clear_all(tmp);
#ifdef HAVE_EPOLL
        ast_channel_epfd_set(tmp, -1);
#endif

        ast_channel_hold_state_set(tmp, AST_CONTROL_UNHOLD);

        ast_channel_internal_setup_topics(tmp);

        headp = ast_channel_varshead(tmp);
        AST_LIST_HEAD_INIT_NOLOCK(headp);

        return tmp;
}

static int __ast_queue_frame(struct ast_channel *chan, struct ast_frame *fin, int head, struct ast_frame *after)
{
        struct ast_frame *f;
        struct ast_frame *cur;
        unsigned int new_frames = 0;
        unsigned int new_voice_frames = 0;
        unsigned int queued_frames = 0;
        unsigned int queued_voice_frames = 0;
        AST_LIST_HEAD_NOLOCK(,ast_frame) frames;

        ast_channel_lock(chan);

        /*
         * Check the last frame on the queue if we are queuing the new
         * frames after it.
         */
        cur = AST_LIST_LAST(ast_channel_readq(chan));
        if (cur && cur->frametype == AST_FRAME_CONTROL && !head && (!after || after == cur)) {
                switch (cur->subclass.integer) {
                case AST_CONTROL_END_OF_Q:
                        if (fin->frametype == AST_FRAME_CONTROL
                                && fin->subclass.integer == AST_CONTROL_HANGUP) {
                                /*
                                 * Destroy the end-of-Q marker frame so we can queue the hangup
                                 * frame in its place.
                                 */
                                AST_LIST_REMOVE(ast_channel_readq(chan), cur, frame_list);
                                ast_frfree(cur);

                                /*
                                 * This has degenerated to a normal queue append anyway.  Since
                                 * we just destroyed the last frame in the queue we must make
                                 * sure that "after" is NULL or bad things will happen.
                                 */
                                after = NULL;
                                break;
                        }
                        /* Fall through */
                case AST_CONTROL_HANGUP:
                        /* Don't queue anything. */
                        ast_channel_unlock(chan);
                        return 0;
                default:
                        break;
                }
        }

        /* Build copies of all the new frames and count them */
        AST_LIST_HEAD_INIT_NOLOCK(&frames);
        for (cur = fin; cur; cur = AST_LIST_NEXT(cur, frame_list)) {
                if (!(f = ast_frdup(cur))) {
                        if (AST_LIST_FIRST(&frames)) {
                                ast_frfree(AST_LIST_FIRST(&frames));
                        }
                        ast_channel_unlock(chan);
                        return -1;
                }

                AST_LIST_INSERT_TAIL(&frames, f, frame_list);
                new_frames++;
                if (f->frametype == AST_FRAME_VOICE) {
                        new_voice_frames++;
                }
        }

        /* Count how many frames exist on the queue */
        AST_LIST_TRAVERSE(ast_channel_readq(chan), cur, frame_list) {
                queued_frames++;
                if (cur->frametype == AST_FRAME_VOICE) {
                        queued_voice_frames++;
                }
        }

        if ((queued_frames + new_frames > 128 || queued_voice_frames + new_voice_frames > 96)) {
                int count = 0;
                ast_log(LOG_WARNING, "Exceptionally long %squeue length queuing to %s\n", queued_frames + new_frames > 128 ? "" : "voice ", ast_channel_name(chan));
                AST_LIST_TRAVERSE_SAFE_BEGIN(ast_channel_readq(chan), cur, frame_list) {
                        /* Save the most recent frame */
                        if (!AST_LIST_NEXT(cur, frame_list)) {
                                break;
                        } else if (cur->frametype == AST_FRAME_VOICE || cur->frametype == AST_FRAME_VIDEO || cur->frametype == AST_FRAME_NULL) {
                                if (++count > 64) {
                                        break;
                                }
                                AST_LIST_REMOVE_CURRENT(frame_list);
                                ast_frfree(cur);

                                /* Read from the alert pipe for each flushed frame. */
                                ast_channel_internal_alert_read(chan);
                        }
                }
                AST_LIST_TRAVERSE_SAFE_END;
        }

        if (after) {
                AST_LIST_INSERT_LIST_AFTER(ast_channel_readq(chan), &frames, after, frame_list);
        } else {
                if (head) {
                        AST_LIST_APPEND_LIST(&frames, ast_channel_readq(chan), frame_list);
                        AST_LIST_HEAD_INIT_NOLOCK(ast_channel_readq(chan));
                }
                AST_LIST_APPEND_LIST(ast_channel_readq(chan), &frames, frame_list);
        }

        if (ast_channel_alert_writable(chan)) {
                /* Write to the alert pipe for each added frame */
                while (new_frames--) {
                        if (ast_channel_alert_write(chan)) {
                                ast_log(LOG_WARNING, "Unable to write to alert pipe on %s (qlen = %u): %s!\n",
                                        ast_channel_name(chan), queued_frames, strerror(errno));
                                break;
                        }
                }
        } else if (ast_channel_timingfd(chan) > -1) {
                ast_timer_enable_continuous(ast_channel_timer(chan));
        } else if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING)) {
                pthread_kill(ast_channel_blocker(chan), SIGURG);
        }

        ast_channel_unlock(chan);

        return 0;
}

int ast_queue_frame(struct ast_channel *chan, struct ast_frame *fin)
{
        return __ast_queue_frame(chan, fin, 0, NULL);
}

int ast_queue_frame_head(struct ast_channel *chan, struct ast_frame *fin)
{
        return __ast_queue_frame(chan, fin, 1, NULL);
}

/*! \brief Queue a hangup frame for channel */
int ast_queue_hangup(struct ast_channel *chan)
{
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = AST_CONTROL_HANGUP };
        int res;

        /* Yeah, let's not change a lock-critical value without locking */
        ast_channel_lock(chan);
        ast_channel_softhangup_internal_flag_add(chan, AST_SOFTHANGUP_DEV);
        ast_channel_publish_blob(chan, ast_channel_hangup_request_type(), NULL);

        res = ast_queue_frame(chan, &f);
        ast_channel_unlock(chan);
        return res;
}

/*! \brief Queue a hangup frame for channel */
int ast_queue_hangup_with_cause(struct ast_channel *chan, int cause)
{
        RAII_VAR(struct ast_json *, blob, NULL, ast_json_unref);
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = AST_CONTROL_HANGUP };
        int res;

        if (cause >= 0) {
                f.data.uint32 = cause;
        }

        /* Yeah, let's not change a lock-critical value without locking */
        ast_channel_lock(chan);
        ast_channel_softhangup_internal_flag_add(chan, AST_SOFTHANGUP_DEV);
        if (cause < 0) {
                f.data.uint32 = ast_channel_hangupcause(chan);
        }
        blob = ast_json_pack("{s: i}",
                             "cause", cause);
        ast_channel_publish_blob(chan, ast_channel_hangup_request_type(), blob);

        res = ast_queue_frame(chan, &f);
        ast_channel_unlock(chan);
        return res;
}

int ast_queue_hold(struct ast_channel *chan, const char *musicclass)
{
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = AST_CONTROL_HOLD };
        struct ast_json *blob = NULL;
        int res;

        if (!ast_strlen_zero(musicclass)) {
                f.data.ptr = (void *) musicclass;
                f.datalen = strlen(musicclass) + 1;

                blob = ast_json_pack("{s: s}",
                                     "musicclass", musicclass);
        }

        ast_channel_publish_cached_blob(chan, ast_channel_hold_type(), blob);

        res = ast_queue_frame(chan, &f);

        ast_json_unref(blob);

        return res;
}

int ast_queue_unhold(struct ast_channel *chan)
{
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = AST_CONTROL_UNHOLD };
        int res;

        ast_channel_publish_cached_blob(chan, ast_channel_unhold_type(), NULL);

        res = ast_queue_frame(chan, &f);

        return res;
}

/*! \brief Queue a control frame */
int ast_queue_control(struct ast_channel *chan, enum ast_control_frame_type control)
{
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = control };
        return ast_queue_frame(chan, &f);
}

/*! \brief Queue a control frame with payload */
int ast_queue_control_data(struct ast_channel *chan, enum ast_control_frame_type control,
                           const void *data, size_t datalen)
{
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = control, .data.ptr = (void *) data, .datalen = datalen };
        return ast_queue_frame(chan, &f);
}

/*! \brief Set defer DTMF flag on channel */
int ast_channel_defer_dtmf(struct ast_channel *chan)
{
        int pre = 0;

        if (chan) {
                pre = ast_test_flag(ast_channel_flags(chan), AST_FLAG_DEFER_DTMF);
                ast_set_flag(ast_channel_flags(chan), AST_FLAG_DEFER_DTMF);
        }
        return pre;
}

/*! \brief Unset defer DTMF flag on channel */
void ast_channel_undefer_dtmf(struct ast_channel *chan)
{
        if (chan)
                ast_clear_flag(ast_channel_flags(chan), AST_FLAG_DEFER_DTMF);
}

struct ast_channel *ast_channel_callback(ao2_callback_data_fn *cb_fn, void *arg,
                void *data, int ao2_flags)
{
        return ao2_callback_data(channels, ao2_flags, cb_fn, arg, data);
}

static int ast_channel_by_name_cb(void *obj, void *arg, void *data, int flags)
{
        struct ast_channel *chan = obj;
        const char *name = arg;
        size_t name_len = *(size_t *) data;
        int ret = CMP_MATCH;

        if (ast_strlen_zero(name)) {
                ast_log(LOG_ERROR, "BUG! Must supply a channel name or partial name to match!\n");
                return CMP_STOP;
        }

        ast_channel_lock(chan);
        if ((!name_len && strcasecmp(ast_channel_name(chan), name))
                || (name_len && strncasecmp(ast_channel_name(chan), name, name_len))) {
                ret = 0; /* name match failed, keep looking */
        }
        ast_channel_unlock(chan);

        return ret;
}

static int ast_channel_by_exten_cb(void *obj, void *arg, void *data, int flags)
{
        struct ast_channel *chan = obj;
        char *context = arg;
        char *exten = data;
        int ret = CMP_MATCH;

        if (ast_strlen_zero(exten) || ast_strlen_zero(context)) {
                ast_log(LOG_ERROR, "BUG! Must have a context and extension to match!\n");
                return CMP_STOP;
        }

        ast_channel_lock(chan);
        if (strcasecmp(ast_channel_context(chan), context) && strcasecmp(ast_channel_macrocontext(chan), context)) {
                ret = 0; /* Context match failed, continue */
        } else if (strcasecmp(ast_channel_exten(chan), exten) && strcasecmp(ast_channel_macroexten(chan), exten)) {
                ret = 0; /* Extension match failed, continue */
        }
        ast_channel_unlock(chan);

        return ret;
}

static int ast_channel_by_uniqueid_cb(void *obj, void *arg, void *data, int flags)
{
        struct ast_channel *chan = obj;
        char *uniqueid = arg;
        size_t id_len = *(size_t *) data;
        int ret = CMP_MATCH;

        if (ast_strlen_zero(uniqueid)) {
                ast_log(LOG_ERROR, "BUG! Must supply a uniqueid or partial uniqueid to match!\n");
                return CMP_STOP;
        }

        ast_channel_lock(chan);
        if ((!id_len && strcasecmp(ast_channel_uniqueid(chan), uniqueid))
                || (id_len && strncasecmp(ast_channel_uniqueid(chan), uniqueid, id_len))) {
                ret = 0; /* uniqueid match failed, keep looking */
        }
        ast_channel_unlock(chan);

        return ret;
}

struct ast_channel_iterator {
        /* storage for non-dynamically allocated iterator */
        struct ao2_iterator simple_iterator;
        /* pointer to the actual iterator (simple_iterator or a dynamically
         * allocated iterator)
         */
        struct ao2_iterator *active_iterator;
};

struct ast_channel_iterator *ast_channel_iterator_destroy(struct ast_channel_iterator *i)
{
        ao2_iterator_destroy(i->active_iterator);
        ast_free(i);

        return NULL;
}

struct ast_channel_iterator *ast_channel_iterator_by_exten_new(const char *exten, const char *context)
{
        struct ast_channel_iterator *i;
        char *l_exten = (char *) exten;
        char *l_context = (char *) context;

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

        i->active_iterator = (void *) ast_channel_callback(ast_channel_by_exten_cb,
                l_context, l_exten, OBJ_MULTIPLE);
        if (!i->active_iterator) {
                ast_free(i);
                return NULL;
        }

        return i;
}

struct ast_channel_iterator *ast_channel_iterator_by_name_new(const char *name, size_t name_len)
{
        struct ast_channel_iterator *i;
        char *l_name = (char *) name;

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

        i->active_iterator = (void *) ast_channel_callback(ast_channel_by_name_cb,
                l_name, &name_len,
                OBJ_MULTIPLE | (name_len == 0 /* match the whole word, so optimize */ ? OBJ_KEY : 0));
        if (!i->active_iterator) {
                ast_free(i);
                return NULL;
        }

        return i;
}

struct ast_channel_iterator *ast_channel_iterator_all_new(void)
{
        struct ast_channel_iterator *i;

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

        i->simple_iterator = ao2_iterator_init(channels, 0);
        i->active_iterator = &i->simple_iterator;

        return i;
}

struct ast_channel *ast_channel_iterator_next(struct ast_channel_iterator *i)
{
        return ao2_iterator_next(i->active_iterator);
}

/* Legacy function, not currently used for lookups, but we need a cmp_fn */
static int ast_channel_cmp_cb(void *obj, void *arg, int flags)
{
        ast_log(LOG_ERROR, "BUG! Should never be called!\n");
        return CMP_STOP;
}

struct ast_channel *ast_channel_get_by_name_prefix(const char *name, size_t name_len)
{
        struct ast_channel *chan;
        char *l_name = (char *) name;

        chan = ast_channel_callback(ast_channel_by_name_cb, l_name, &name_len,
                (name_len == 0) /* optimize if it is a complete name match */ ? OBJ_KEY : 0);
        if (chan) {
                return chan;
        }

        if (ast_strlen_zero(l_name)) {
                /* We didn't have a name to search for so quit. */
                return NULL;
        }

        /* Now try a search for uniqueid. */
        return ast_channel_callback(ast_channel_by_uniqueid_cb, l_name, &name_len, 0);
}

struct ast_channel *ast_channel_get_by_name(const char *name)
{
        return ast_channel_get_by_name_prefix(name, 0);
}

struct ast_channel *ast_channel_get_by_exten(const char *exten, const char *context)
{
        char *l_exten = (char *) exten;
        char *l_context = (char *) context;

        return ast_channel_callback(ast_channel_by_exten_cb, l_context, l_exten, 0);
}

int ast_is_deferrable_frame(const struct ast_frame *frame)
{
        /* Do not add a default entry in this switch statement.  Each new
         * frame type should be addressed directly as to whether it should
         * be queued up or not.
         */
        switch (frame->frametype) {
        case AST_FRAME_BRIDGE_ACTION:
        case AST_FRAME_BRIDGE_ACTION_SYNC:
        case AST_FRAME_CONTROL:
        case AST_FRAME_TEXT:
        case AST_FRAME_IMAGE:
        case AST_FRAME_HTML:
                return 1;

        case AST_FRAME_DTMF_END:
        case AST_FRAME_DTMF_BEGIN:
        case AST_FRAME_VOICE:
        case AST_FRAME_VIDEO:
        case AST_FRAME_NULL:
        case AST_FRAME_IAX:
        case AST_FRAME_CNG:
        case AST_FRAME_MODEM:
        case AST_FRAME_RTCP:
                return 0;
        }
        return 0;
}

/*! \brief Wait, look for hangups and condition arg */
int ast_safe_sleep_conditional(struct ast_channel *chan, int timeout_ms, int (*cond)(void*), void *data)
{
        struct ast_frame *f;
        struct ast_silence_generator *silgen = NULL;
        int res = 0;
        struct timeval start;
        int ms;
        AST_LIST_HEAD_NOLOCK(, ast_frame) deferred_frames;

        AST_LIST_HEAD_INIT_NOLOCK(&deferred_frames);

        /* If no other generator is present, start silencegen while waiting */
        if (ast_opt_transmit_silence && !ast_channel_generatordata(chan)) {
                silgen = ast_channel_start_silence_generator(chan);
        }

        start = ast_tvnow();
        while ((ms = ast_remaining_ms(start, timeout_ms))) {
                struct ast_frame *dup_f = NULL;

                if (cond && ((*cond)(data) == 0)) {
                        break;
                }
                ms = ast_waitfor(chan, ms);
                if (ms < 0) {
                        res = -1;
                        break;
                }
                if (ms > 0) {
                        f = ast_read(chan);
                        if (!f) {
                                res = -1;
                                break;
                        }

                        if (!ast_is_deferrable_frame(f)) {
                                ast_frfree(f);
                                continue;
                        }

                        if ((dup_f = ast_frisolate(f))) {
                                if (dup_f != f) {
                                        ast_frfree(f);
                                }
                                AST_LIST_INSERT_HEAD(&deferred_frames, dup_f, frame_list);
                        }
                }
        }

        /* stop silgen if present */
        if (silgen) {
                ast_channel_stop_silence_generator(chan, silgen);
        }

        /* We need to free all the deferred frames, but we only need to
         * queue the deferred frames if there was no error and no
         * hangup was received
         */
        ast_channel_lock(chan);
        while ((f = AST_LIST_REMOVE_HEAD(&deferred_frames, frame_list))) {
                if (!res) {
                        ast_queue_frame_head(chan, f);
                }
                ast_frfree(f);
        }
        ast_channel_unlock(chan);

        return res;
}

/*! \brief Wait, look for hangups */
int ast_safe_sleep(struct ast_channel *chan, int ms)
{
        return ast_safe_sleep_conditional(chan, ms, NULL, NULL);
}

struct ast_channel *ast_channel_release(struct ast_channel *chan)
{
        /* Safe, even if already unlinked. */
        ao2_unlink(channels, chan);
        return ast_channel_unref(chan);
}

void ast_party_name_init(struct ast_party_name *init)
{
        init->str = NULL;
        init->char_set = AST_PARTY_CHAR_SET_ISO8859_1;
        init->presentation = AST_PRES_ALLOWED_USER_NUMBER_NOT_SCREENED;
        init->valid = 0;
}

void ast_party_name_copy(struct ast_party_name *dest, const struct ast_party_name *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_free(dest->str);
        dest->str = ast_strdup(src->str);
        dest->char_set = src->char_set;
        dest->presentation = src->presentation;
        dest->valid = src->valid;
}

void ast_party_name_set_init(struct ast_party_name *init, const struct ast_party_name *guide)
{
        init->str = NULL;
        init->char_set = guide->char_set;
        init->presentation = guide->presentation;
        init->valid = guide->valid;
}

void ast_party_name_set(struct ast_party_name *dest, const struct ast_party_name *src)
{
        if (dest == src) {
                /* Don't set to self */
                return;
        }

        if (src->str && src->str != dest->str) {
                ast_free(dest->str);
                dest->str = ast_strdup(src->str);
        }

        dest->char_set = src->char_set;
        dest->presentation = src->presentation;
        dest->valid = src->valid;
}

void ast_party_name_free(struct ast_party_name *doomed)
{
        ast_free(doomed->str);
        doomed->str = NULL;
}

void ast_party_number_init(struct ast_party_number *init)
{
        init->str = NULL;
        init->plan = 0;/* Unknown */
        init->presentation = AST_PRES_ALLOWED_USER_NUMBER_NOT_SCREENED;
        init->valid = 0;
}

void ast_party_number_copy(struct ast_party_number *dest, const struct ast_party_number *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_free(dest->str);
        dest->str = ast_strdup(src->str);
        dest->plan = src->plan;
        dest->presentation = src->presentation;
        dest->valid = src->valid;
}

void ast_party_number_set_init(struct ast_party_number *init, const struct ast_party_number *guide)
{
        init->str = NULL;
        init->plan = guide->plan;
        init->presentation = guide->presentation;
        init->valid = guide->valid;
}

void ast_party_number_set(struct ast_party_number *dest, const struct ast_party_number *src)
{
        if (dest == src) {
                /* Don't set to self */
                return;
        }

        if (src->str && src->str != dest->str) {
                ast_free(dest->str);
                dest->str = ast_strdup(src->str);
        }

        dest->plan = src->plan;
        dest->presentation = src->presentation;
        dest->valid = src->valid;
}

void ast_party_number_free(struct ast_party_number *doomed)
{
        ast_free(doomed->str);
        doomed->str = NULL;
}

void ast_party_subaddress_init(struct ast_party_subaddress *init)
{
        init->str = NULL;
        init->type = 0;
        init->odd_even_indicator = 0;
        init->valid = 0;
}

void ast_party_subaddress_copy(struct ast_party_subaddress *dest, const struct ast_party_subaddress *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_free(dest->str);
        dest->str = ast_strdup(src->str);
        dest->type = src->type;
        dest->odd_even_indicator = src->odd_even_indicator;
        dest->valid = src->valid;
}

void ast_party_subaddress_set_init(struct ast_party_subaddress *init, const struct ast_party_subaddress *guide)
{
        init->str = NULL;
        init->type = guide->type;
        init->odd_even_indicator = guide->odd_even_indicator;
        init->valid = guide->valid;
}

void ast_party_subaddress_set(struct ast_party_subaddress *dest, const struct ast_party_subaddress *src)
{
        if (dest == src) {
                /* Don't set to self */
                return;
        }

        if (src->str && src->str != dest->str) {
                ast_free(dest->str);
                dest->str = ast_strdup(src->str);
        }

        dest->type = src->type;
        dest->odd_even_indicator = src->odd_even_indicator;
        dest->valid = src->valid;
}

void ast_party_subaddress_free(struct ast_party_subaddress *doomed)
{
        ast_free(doomed->str);
        doomed->str = NULL;
}

void ast_set_party_id_all(struct ast_set_party_id *update_id)
{
        update_id->name = 1;
        update_id->number = 1;
        update_id->subaddress = 1;
}

void ast_party_id_init(struct ast_party_id *init)
{
        ast_party_name_init(&init->name);
        ast_party_number_init(&init->number);
        ast_party_subaddress_init(&init->subaddress);
        init->tag = NULL;
}

void ast_party_id_copy(struct ast_party_id *dest, const struct ast_party_id *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_party_name_copy(&dest->name, &src->name);
        ast_party_number_copy(&dest->number, &src->number);
        ast_party_subaddress_copy(&dest->subaddress, &src->subaddress);

        ast_free(dest->tag);
        dest->tag = ast_strdup(src->tag);
}

void ast_party_id_set_init(struct ast_party_id *init, const struct ast_party_id *guide)
{
        ast_party_name_set_init(&init->name, &guide->name);
        ast_party_number_set_init(&init->number, &guide->number);
        ast_party_subaddress_set_init(&init->subaddress, &guide->subaddress);
        init->tag = NULL;
}

void ast_party_id_set(struct ast_party_id *dest, const struct ast_party_id *src, const struct ast_set_party_id *update)
{
        if (dest == src) {
                /* Don't set to self */
                return;
        }

        if (!update || update->name) {
                ast_party_name_set(&dest->name, &src->name);
        }
        if (!update || update->number) {
                ast_party_number_set(&dest->number, &src->number);
        }
        if (!update || update->subaddress) {
                ast_party_subaddress_set(&dest->subaddress, &src->subaddress);
        }

        if (src->tag && src->tag != dest->tag) {
                ast_free(dest->tag);
                dest->tag = ast_strdup(src->tag);
        }
}

void ast_party_id_free(struct ast_party_id *doomed)
{
        ast_party_name_free(&doomed->name);
        ast_party_number_free(&doomed->number);
        ast_party_subaddress_free(&doomed->subaddress);

        ast_free(doomed->tag);
        doomed->tag = NULL;
}

int ast_party_id_presentation(const struct ast_party_id *id)
{
        int number_priority;
        int number_value;
        int number_screening;
        int name_priority;
        int name_value;

        /* Determine name presentation priority. */
        if (!id->name.valid) {
                name_value = AST_PRES_UNAVAILABLE;
                name_priority = 3;
        } else {
                name_value = id->name.presentation & AST_PRES_RESTRICTION;
                switch (name_value) {
                case AST_PRES_RESTRICTED:
                        name_priority = 0;
                        break;
                case AST_PRES_ALLOWED:
                        name_priority = 1;
                        break;
                case AST_PRES_UNAVAILABLE:
                        name_priority = 2;
                        break;
                default:
                        name_value = AST_PRES_UNAVAILABLE;
                        name_priority = 3;
                        break;
                }
        }

        /* Determine number presentation priority. */
        if (!id->number.valid) {
                number_screening = AST_PRES_USER_NUMBER_UNSCREENED;
                number_value = AST_PRES_UNAVAILABLE;
                number_priority = 3;
        } else {
                number_screening = id->number.presentation & AST_PRES_NUMBER_TYPE;
                number_value = id->number.presentation & AST_PRES_RESTRICTION;
                switch (number_value) {
                case AST_PRES_RESTRICTED:
                        number_priority = 0;
                        break;
                case AST_PRES_ALLOWED:
                        number_priority = 1;
                        break;
                case AST_PRES_UNAVAILABLE:
                        number_priority = 2;
                        break;
                default:
                        number_screening = AST_PRES_USER_NUMBER_UNSCREENED;
                        number_value = AST_PRES_UNAVAILABLE;
                        number_priority = 3;
                        break;
                }
        }

        /* Select the wining presentation value. */
        if (name_priority < number_priority) {
                number_value = name_value;
        }
        if (number_value == AST_PRES_UNAVAILABLE) {
                return AST_PRES_NUMBER_NOT_AVAILABLE;
        }

        return number_value | number_screening;
}

void ast_party_id_invalidate(struct ast_party_id *id)
{
        id->name.valid = 0;
        id->number.valid = 0;
        id->subaddress.valid = 0;
}

void ast_party_id_reset(struct ast_party_id *id)
{
        ast_party_id_free(id);
        ast_party_id_init(id);
}

struct ast_party_id ast_party_id_merge(struct ast_party_id *base, struct ast_party_id *overlay)
{
        struct ast_party_id merged;

        merged = *base;
        if (overlay->name.valid) {
                merged.name = overlay->name;
        }
        if (overlay->number.valid) {
                merged.number = overlay->number;
        }
        if (overlay->subaddress.valid) {
                merged.subaddress = overlay->subaddress;
        }
        /* Note the actual structure is returned and not a pointer to it! */
        return merged;
}

void ast_party_id_merge_copy(struct ast_party_id *dest, struct ast_party_id *base, struct ast_party_id *overlay)
{
        struct ast_party_id merged;

        merged = ast_party_id_merge(base, overlay);
        ast_party_id_copy(dest, &merged);
}

void ast_party_dialed_init(struct ast_party_dialed *init)
{
        init->number.str = NULL;
        init->number.plan = 0;/* Unknown */
        ast_party_subaddress_init(&init->subaddress);
        init->transit_network_select = 0;
}

void ast_party_dialed_copy(struct ast_party_dialed *dest, const struct ast_party_dialed *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_free(dest->number.str);
        dest->number.str = ast_strdup(src->number.str);
        dest->number.plan = src->number.plan;
        ast_party_subaddress_copy(&dest->subaddress, &src->subaddress);
        dest->transit_network_select = src->transit_network_select;
}

void ast_party_dialed_set_init(struct ast_party_dialed *init, const struct ast_party_dialed *guide)
{
        init->number.str = NULL;
        init->number.plan = guide->number.plan;
        ast_party_subaddress_set_init(&init->subaddress, &guide->subaddress);
        init->transit_network_select = guide->transit_network_select;
}

void ast_party_dialed_set(struct ast_party_dialed *dest, const struct ast_party_dialed *src)
{
        if (src->number.str && src->number.str != dest->number.str) {
                ast_free(dest->number.str);
                dest->number.str = ast_strdup(src->number.str);
        }
        dest->number.plan = src->number.plan;

        ast_party_subaddress_set(&dest->subaddress, &src->subaddress);

        dest->transit_network_select = src->transit_network_select;
}

void ast_party_dialed_free(struct ast_party_dialed *doomed)
{
        ast_free(doomed->number.str);
        doomed->number.str = NULL;
        ast_party_subaddress_free(&doomed->subaddress);
}

void ast_party_caller_init(struct ast_party_caller *init)
{
        ast_party_id_init(&init->id);
        ast_party_id_init(&init->ani);
        ast_party_id_init(&init->priv);
        init->ani2 = 0;
}

void ast_party_caller_copy(struct ast_party_caller *dest, const struct ast_party_caller *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_party_id_copy(&dest->id, &src->id);
        ast_party_id_copy(&dest->ani, &src->ani);
        ast_party_id_copy(&dest->priv, &src->priv);
        dest->ani2 = src->ani2;
}

void ast_party_caller_set_init(struct ast_party_caller *init, const struct ast_party_caller *guide)
{
        ast_party_id_set_init(&init->id, &guide->id);
        ast_party_id_set_init(&init->ani, &guide->ani);
        ast_party_id_set_init(&init->priv, &guide->priv);
        init->ani2 = guide->ani2;
}

void ast_party_caller_set(struct ast_party_caller *dest, const struct ast_party_caller *src, const struct ast_set_party_caller *update)
{
        ast_party_id_set(&dest->id, &src->id, update ? &update->id : NULL);
        ast_party_id_set(&dest->ani, &src->ani, update ? &update->ani : NULL);
        ast_party_id_set(&dest->priv, &src->priv, update ? &update->priv : NULL);
        dest->ani2 = src->ani2;
}

void ast_party_caller_free(struct ast_party_caller *doomed)
{
        ast_party_id_free(&doomed->id);
        ast_party_id_free(&doomed->ani);
        ast_party_id_free(&doomed->priv);
}

void ast_party_connected_line_init(struct ast_party_connected_line *init)
{
        ast_party_id_init(&init->id);
        ast_party_id_init(&init->ani);
        ast_party_id_init(&init->priv);
        init->ani2 = 0;
        init->source = AST_CONNECTED_LINE_UPDATE_SOURCE_UNKNOWN;
}

void ast_party_connected_line_copy(struct ast_party_connected_line *dest, const struct ast_party_connected_line *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_party_id_copy(&dest->id, &src->id);
        ast_party_id_copy(&dest->ani, &src->ani);
        ast_party_id_copy(&dest->priv, &src->priv);
        dest->ani2 = src->ani2;
        dest->source = src->source;
}

void ast_party_connected_line_set_init(struct ast_party_connected_line *init, const struct ast_party_connected_line *guide)
{
        ast_party_id_set_init(&init->id, &guide->id);
        ast_party_id_set_init(&init->ani, &guide->ani);
        ast_party_id_set_init(&init->priv, &guide->priv);
        init->ani2 = guide->ani2;
        init->source = guide->source;
}

void ast_party_connected_line_set(struct ast_party_connected_line *dest, const struct ast_party_connected_line *src, const struct ast_set_party_connected_line *update)
{
        ast_party_id_set(&dest->id, &src->id, update ? &update->id : NULL);
        ast_party_id_set(&dest->ani, &src->ani, update ? &update->ani : NULL);
        ast_party_id_set(&dest->priv, &src->priv, update ? &update->priv : NULL);
        dest->ani2 = src->ani2;
        dest->source = src->source;
}

void ast_party_connected_line_collect_caller(struct ast_party_connected_line *connected, struct ast_party_caller *caller)
{
        connected->id = caller->id;
        connected->ani = caller->ani;
        connected->priv = caller->priv;
        connected->ani2 = caller->ani2;
        connected->source = AST_CONNECTED_LINE_UPDATE_SOURCE_UNKNOWN;
}

void ast_party_connected_line_free(struct ast_party_connected_line *doomed)
{
        ast_party_id_free(&doomed->id);
        ast_party_id_free(&doomed->ani);
        ast_party_id_free(&doomed->priv);
}

void ast_party_redirecting_reason_init(struct ast_party_redirecting_reason *init)
{
        init->str = NULL;
        init->code = AST_REDIRECTING_REASON_UNKNOWN;
}

void ast_party_redirecting_reason_copy(struct ast_party_redirecting_reason *dest, const struct ast_party_redirecting_reason *src)
{
        if (dest == src) {
                return;
        }

        ast_free(dest->str);
        dest->str = ast_strdup(src->str);
        dest->code = src->code;
}

void ast_party_redirecting_reason_set_init(struct ast_party_redirecting_reason *init, const struct ast_party_redirecting_reason *guide)
{
        init->str = NULL;
        init->code = guide->code;
}

void ast_party_redirecting_reason_set(struct ast_party_redirecting_reason *dest, const struct ast_party_redirecting_reason *src)
{
        if (dest == src) {
                return;
        }

        if (src->str && src->str != dest->str) {
                ast_free(dest->str);
                dest->str = ast_strdup(src->str);
        }

        dest->code = src->code;
}

void ast_party_redirecting_reason_free(struct ast_party_redirecting_reason *doomed)
{
        ast_free(doomed->str);
}


void ast_party_redirecting_init(struct ast_party_redirecting *init)
{
        ast_party_id_init(&init->orig);
        ast_party_id_init(&init->from);
        ast_party_id_init(&init->to);
        ast_party_id_init(&init->priv_orig);
        ast_party_id_init(&init->priv_from);
        ast_party_id_init(&init->priv_to);
        ast_party_redirecting_reason_init(&init->reason);
        ast_party_redirecting_reason_init(&init->orig_reason);
        init->count = 0;
}

void ast_party_redirecting_copy(struct ast_party_redirecting *dest, const struct ast_party_redirecting *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_party_id_copy(&dest->orig, &src->orig);
        ast_party_id_copy(&dest->from, &src->from);
        ast_party_id_copy(&dest->to, &src->to);
        ast_party_id_copy(&dest->priv_orig, &src->priv_orig);
        ast_party_id_copy(&dest->priv_from, &src->priv_from);
        ast_party_id_copy(&dest->priv_to, &src->priv_to);
        ast_party_redirecting_reason_copy(&dest->reason, &src->reason);
        ast_party_redirecting_reason_copy(&dest->orig_reason, &src->orig_reason);
        dest->count = src->count;
}

void ast_party_redirecting_set_init(struct ast_party_redirecting *init, const struct ast_party_redirecting *guide)
{
        ast_party_id_set_init(&init->orig, &guide->orig);
        ast_party_id_set_init(&init->from, &guide->from);
        ast_party_id_set_init(&init->to, &guide->to);
        ast_party_id_set_init(&init->priv_orig, &guide->priv_orig);
        ast_party_id_set_init(&init->priv_from, &guide->priv_from);
        ast_party_id_set_init(&init->priv_to, &guide->priv_to);
        ast_party_redirecting_reason_set_init(&init->reason, &guide->reason);
        ast_party_redirecting_reason_set_init(&init->orig_reason, &guide->orig_reason);
        init->count = guide->count;
}

void ast_party_redirecting_set(struct ast_party_redirecting *dest, const struct ast_party_redirecting *src, const struct ast_set_party_redirecting *update)
{
        ast_party_id_set(&dest->orig, &src->orig, update ? &update->orig : NULL);
        ast_party_id_set(&dest->from, &src->from, update ? &update->from : NULL);
        ast_party_id_set(&dest->to, &src->to, update ? &update->to : NULL);
        ast_party_id_set(&dest->priv_orig, &src->priv_orig, update ? &update->priv_orig : NULL);
        ast_party_id_set(&dest->priv_from, &src->priv_from, update ? &update->priv_from : NULL);
        ast_party_id_set(&dest->priv_to, &src->priv_to, update ? &update->priv_to : NULL);
        ast_party_redirecting_reason_set(&dest->reason, &src->reason);
        ast_party_redirecting_reason_set(&dest->orig_reason, &src->orig_reason);
        dest->count = src->count;
}

void ast_party_redirecting_free(struct ast_party_redirecting *doomed)
{
        ast_party_id_free(&doomed->orig);
        ast_party_id_free(&doomed->from);
        ast_party_id_free(&doomed->to);
        ast_party_id_free(&doomed->priv_orig);
        ast_party_id_free(&doomed->priv_from);
        ast_party_id_free(&doomed->priv_to);
        ast_party_redirecting_reason_free(&doomed->reason);
        ast_party_redirecting_reason_free(&doomed->orig_reason);
}

/*! \brief Free a channel structure */
static void ast_channel_destructor(void *obj)
{
        struct ast_channel *chan = obj;
#ifdef HAVE_EPOLL
        int i;
#endif
        struct ast_var_t *vardata;
        struct ast_frame *f;
        struct varshead *headp;
        struct ast_datastore *datastore;
        char device_name[AST_CHANNEL_NAME];
        ast_callid callid;

        /* Stop monitoring */
        if (ast_channel_monitor(chan)) {
                ast_channel_monitor(chan)->stop(chan, 0);
        }

        /* If there is native format music-on-hold state, free it */
        if (ast_channel_music_state(chan)) {
                ast_moh_cleanup(chan);
        }

        ast_pbx_hangup_handler_destroy(chan);

        /* Things that may possibly raise Stasis messages shouldn't occur after this point */
        ast_set_flag(ast_channel_flags(chan), AST_FLAG_DEAD);

        if (ast_channel_internal_is_finalized(chan)) {
                /* A channel snapshot should not be in the process of being staged now. */
                ast_assert(!ast_test_flag(ast_channel_flags(chan), AST_FLAG_SNAPSHOT_STAGE));

                ast_channel_lock(chan);
                ast_channel_publish_snapshot(chan);
                ast_channel_unlock(chan);
                publish_cache_clear(chan);
        }

        ast_channel_lock(chan);

        /* Get rid of each of the data stores on the channel */
        while ((datastore = AST_LIST_REMOVE_HEAD(ast_channel_datastores(chan), entry)))
                /* Free the data store */
                ast_datastore_free(datastore);

        /* While the channel is locked, take the reference to its callid while we tear down the call. */
        callid = ast_channel_callid(chan);
        ast_channel_callid_cleanup(chan);

        ast_channel_unlock(chan);

        /* Lock and unlock the channel just to be sure nobody has it locked still
           due to a reference that was stored in a datastore. (i.e. app_chanspy) */
        ast_channel_lock(chan);
        ast_channel_unlock(chan);

        if (ast_channel_tech_pvt(chan)) {
                ast_log_callid(LOG_WARNING, callid, "Channel '%s' may not have been hung up properly\n", ast_channel_name(chan));
                ast_free(ast_channel_tech_pvt(chan));
        }

        if (ast_channel_sched(chan)) {
                ast_sched_context_destroy(ast_channel_sched(chan));
        }

        if (ast_channel_internal_is_finalized(chan)) {
                char *dashptr;

                ast_copy_string(device_name, ast_channel_name(chan), sizeof(device_name));
                if ((dashptr = strrchr(device_name, '-'))) {
                        *dashptr = '\0';
                }
        } else {
                device_name[0] = '\0';
        }

        /* Free translators */
        if (ast_channel_readtrans(chan))
                ast_translator_free_path(ast_channel_readtrans(chan));
        if (ast_channel_writetrans(chan))
                ast_translator_free_path(ast_channel_writetrans(chan));
        if (ast_channel_pbx(chan))
                ast_log_callid(LOG_WARNING, callid, "PBX may not have been terminated properly on '%s'\n", ast_channel_name(chan));

        /* Free formats */
        ast_channel_set_oldwriteformat(chan, NULL);
        ast_channel_set_rawreadformat(chan, NULL);
        ast_channel_set_rawwriteformat(chan, NULL);
        ast_channel_set_readformat(chan, NULL);
        ast_channel_set_writeformat(chan, NULL);

        ast_party_dialed_free(ast_channel_dialed(chan));
        ast_party_caller_free(ast_channel_caller(chan));
        ast_party_connected_line_free(ast_channel_connected(chan));
        ast_party_connected_line_free(ast_channel_connected_indicated(chan));
        ast_party_redirecting_free(ast_channel_redirecting(chan));

        /* Close pipes if appropriate */
        ast_channel_internal_alertpipe_close(chan);
        if (ast_channel_timer(chan)) {
                ast_timer_close(ast_channel_timer(chan));
                ast_channel_timer_set(chan, NULL);
        }
#ifdef HAVE_EPOLL
        for (i = 0; i < AST_MAX_FDS; i++) {
                if (ast_channel_internal_epfd_data(chan, i)) {
                        ast_free(ast_channel_internal_epfd_data(chan, i));
                }
        }
        close(ast_channel_epfd(chan));
#endif
        while ((f = AST_LIST_REMOVE_HEAD(ast_channel_readq(chan), frame_list)))
                ast_frfree(f);

        /* loop over the variables list, freeing all data and deleting list items */
        /* no need to lock the list, as the channel is already locked */
        headp = ast_channel_varshead(chan);
        while ((vardata = AST_LIST_REMOVE_HEAD(headp, entries)))
                ast_var_delete(vardata);

        ast_app_group_discard(chan);

        /* Destroy the jitterbuffer */
        ast_jb_destroy(chan);

        if (ast_channel_cdr(chan)) {
                ast_cdr_free(ast_channel_cdr(chan));
                ast_channel_cdr_set(chan, NULL);
        }

        if (ast_channel_zone(chan)) {
                ast_channel_zone_set(chan, ast_tone_zone_unref(ast_channel_zone(chan)));
        }

        ast_channel_internal_cleanup(chan);

        if (device_name[0]) {
                /*
                 * We have a device name to notify of a new state.
                 *
                 * Queue an unknown state, because, while we know that this particular
                 * instance is dead, we don't know the state of all other possible
                 * instances.
                 */
                ast_devstate_changed_literal(AST_DEVICE_UNKNOWN, (ast_test_flag(ast_channel_flags(chan), AST_FLAG_DISABLE_DEVSTATE_CACHE) ? AST_DEVSTATE_NOT_CACHABLE : AST_DEVSTATE_CACHABLE), device_name);
        }

        ast_channel_nativeformats_set(chan, NULL);

        ast_channel_named_callgroups_set(chan, NULL);
        ast_channel_named_pickupgroups_set(chan, NULL);

        ast_atomic_fetchadd_int(&chancount, -1);
}

/*! \brief Free a dummy channel structure */
static void ast_dummy_channel_destructor(void *obj)
{
        struct ast_channel *chan = obj;
        struct ast_datastore *datastore;
        struct ast_var_t *vardata;
        struct varshead *headp;

        ast_pbx_hangup_handler_destroy(chan);

        /* Get rid of each of the data stores on the channel */
        while ((datastore = AST_LIST_REMOVE_HEAD(ast_channel_datastores(chan), entry))) {
                /* Free the data store */
                ast_datastore_free(datastore);
        }

        ast_party_dialed_free(ast_channel_dialed(chan));
        ast_party_caller_free(ast_channel_caller(chan));
        ast_party_connected_line_free(ast_channel_connected(chan));
        ast_party_connected_line_free(ast_channel_connected_indicated(chan));
        ast_party_redirecting_free(ast_channel_redirecting(chan));

        /* loop over the variables list, freeing all data and deleting list items */
        /* no need to lock the list, as the channel is already locked */
        headp = ast_channel_varshead(chan);
        while ((vardata = AST_LIST_REMOVE_HEAD(headp, entries)))
                ast_var_delete(vardata);

        if (ast_channel_cdr(chan)) {
                ast_cdr_free(ast_channel_cdr(chan));
                ast_channel_cdr_set(chan, NULL);
        }

        ast_channel_internal_cleanup(chan);
}

struct ast_datastore *ast_channel_datastore_alloc(const struct ast_datastore_info *info, const char *uid)
{
        return ast_datastore_alloc(info, uid);
}

int ast_channel_datastore_free(struct ast_datastore *datastore)
{
        return ast_datastore_free(datastore);
}

int ast_channel_datastore_inherit(struct ast_channel *from, struct ast_channel *to)
{
        struct ast_datastore *datastore = NULL, *datastore2;

        AST_LIST_TRAVERSE(ast_channel_datastores(from), datastore, entry) {
                if (datastore->inheritance > 0) {
                        datastore2 = ast_datastore_alloc(datastore->info, datastore->uid);
                        if (datastore2) {
                                datastore2->data = datastore->info->duplicate ? datastore->info->duplicate(datastore->data) : NULL;
                                datastore2->inheritance = datastore->inheritance == DATASTORE_INHERIT_FOREVER ? DATASTORE_INHERIT_FOREVER : datastore->inheritance - 1;
                                AST_LIST_INSERT_TAIL(ast_channel_datastores(to), datastore2, entry);
                        }
                }
        }
        return 0;
}

int ast_channel_datastore_add(struct ast_channel *chan, struct ast_datastore *datastore)
{
        int res = 0;

        AST_LIST_INSERT_HEAD(ast_channel_datastores(chan), datastore, entry);

        return res;
}

int ast_channel_datastore_remove(struct ast_channel *chan, struct ast_datastore *datastore)
{
        return AST_LIST_REMOVE(ast_channel_datastores(chan), datastore, entry) ? 0 : -1;
}

struct ast_datastore *ast_channel_datastore_find(struct ast_channel *chan, const struct ast_datastore_info *info, const char *uid)
{
        struct ast_datastore *datastore = NULL;

        if (info == NULL)
                return NULL;

        AST_LIST_TRAVERSE(ast_channel_datastores(chan), datastore, entry) {
                if (datastore->info != info) {
                        continue;
                }

                if (uid == NULL) {
                        /* matched by type only */
                        break;
                }

                if ((datastore->uid != NULL) && !strcasecmp(uid, datastore->uid)) {
                        /* Matched by type AND uid */
                        break;
                }
        }

        return datastore;
}

/*! Set the file descriptor on the channel */
void ast_channel_set_fd(struct ast_channel *chan, int which, int fd)
{
#ifdef HAVE_EPOLL
        struct epoll_event ev;
        struct ast_epoll_data *aed = NULL;

        if (ast_channel_fd_isset(chan, which)) {
                epoll_ctl(ast_channel_epfd(chan), EPOLL_CTL_DEL, ast_channel_fd(chan, which), &ev);
                aed = ast_channel_internal_epfd_data(chan, which);
        }

        /* If this new fd is valid, add it to the epoll */
        if (fd > -1) {
                if (!aed && (!(aed = ast_calloc(1, sizeof(*aed)))))
                        return;

                ast_channel_internal_epfd_data_set(chan, which, aed);
                aed->chan = chan;
                aed->which = which;

                ev.events = EPOLLIN | EPOLLPRI | EPOLLERR | EPOLLHUP;
                ev.data.ptr = aed;
                epoll_ctl(ast_channel_epfd(chan), EPOLL_CTL_ADD, fd, &ev);
        } else if (aed) {
                /* We don't have to keep around this epoll data structure now */
                ast_free(aed);
                ast_channel_epfd_data_set(chan, which, NULL);
        }
#endif
        ast_channel_internal_fd_set(chan, which, fd);
        return;
}

/*! Add a channel to an optimized waitfor */
void ast_poll_channel_add(struct ast_channel *chan0, struct ast_channel *chan1)
{
#ifdef HAVE_EPOLL
        struct epoll_event ev;
        int i = 0;

        if (ast_channel_epfd(chan0) == -1)
                return;

        /* Iterate through the file descriptors on chan1, adding them to chan0 */
        for (i = 0; i < AST_MAX_FDS; i++) {
                if (!ast_channel_fd_isset(chan1, i)) {
                        continue;
                }
                ev.events = EPOLLIN | EPOLLPRI | EPOLLERR | EPOLLHUP;
                ev.data.ptr = ast_channel_internal_epfd_data(chan1, i);
                epoll_ctl(ast_channel_epfd(chan0), EPOLL_CTL_ADD, ast_channel_fd(chan1, i), &ev);
        }

#endif
        return;
}

/*! Delete a channel from an optimized waitfor */
void ast_poll_channel_del(struct ast_channel *chan0, struct ast_channel *chan1)
{
#ifdef HAVE_EPOLL
        struct epoll_event ev;
        int i = 0;

        if (ast_channel_epfd(chan0) == -1)
                return;

        for (i = 0; i < AST_MAX_FDS; i++) {
                if (!ast_channel_fd_isset(chan1, i)) {
                        continue;
                }
                epoll_ctl(ast_channel_epfd(chan0), EPOLL_CTL_DEL, ast_channel_fd(chan1, i), &ev);
        }

#endif
        return;
}

void ast_channel_clear_softhangup(struct ast_channel *chan, int flag)
{
        ast_channel_lock(chan);

        ast_channel_softhangup_internal_flag_clear(chan, flag);

        if (!ast_channel_softhangup_internal_flag(chan)) {
                struct ast_frame *fr;

                /* If we have completely cleared the softhangup flag,
                 * then we need to fully abort the hangup process.  This requires
                 * pulling the END_OF_Q frame out of the channel frame queue if it
                 * still happens to be there. */

                fr = AST_LIST_LAST(ast_channel_readq(chan));
                if (fr && fr->frametype == AST_FRAME_CONTROL &&
                                fr->subclass.integer == AST_CONTROL_END_OF_Q) {
                        AST_LIST_REMOVE(ast_channel_readq(chan), fr, frame_list);
                        ast_frfree(fr);
                }
        }

        ast_channel_unlock(chan);
}

/*! \brief Softly hangup a channel, don't lock */
int ast_softhangup_nolock(struct ast_channel *chan, int cause)
{
        ast_debug(1, "Soft-Hanging (%#04x) up channel '%s'\n", (unsigned)cause, ast_channel_name(chan));
        /* Inform channel driver that we need to be hung up, if it cares */
        ast_channel_softhangup_internal_flag_add(chan, cause);
        ast_queue_frame(chan, &ast_null_frame);
        /* Interrupt any poll call or such */
        if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING))
                pthread_kill(ast_channel_blocker(chan), SIGURG);
        return 0;
}

/*! \brief Softly hangup a channel, lock */
int ast_softhangup(struct ast_channel *chan, int cause)
{
        RAII_VAR(struct ast_json *, blob, NULL, ast_json_unref);
        int res;

        ast_channel_lock(chan);
        res = ast_softhangup_nolock(chan, cause);
        blob = ast_json_pack("{s: i, s: b}",
                             "cause", cause,
                             "soft", 1);
        ast_channel_publish_blob(chan, ast_channel_hangup_request_type(), blob);
        ast_channel_unlock(chan);

        return res;
}

static void free_translation(struct ast_channel *clonechan)
{
        if (ast_channel_writetrans(clonechan)) {
                ast_translator_free_path(ast_channel_writetrans(clonechan));
        }
        if (ast_channel_readtrans(clonechan)) {
                ast_translator_free_path(ast_channel_readtrans(clonechan));
        }
        ast_channel_writetrans_set(clonechan, NULL);
        ast_channel_readtrans_set(clonechan, NULL);
}

void ast_set_hangupsource(struct ast_channel *chan, const char *source, int force)
{
        RAII_VAR(struct ast_channel *, bridge, ast_channel_bridge_peer(chan), ast_channel_cleanup);

        ast_channel_lock(chan);
        if (force || ast_strlen_zero(ast_channel_hangupsource(chan))) {
                ast_channel_hangupsource_set(chan, source);
        }
        ast_channel_unlock(chan);

        if (bridge) {
                ast_channel_lock(bridge);
                if (force || ast_strlen_zero(ast_channel_hangupsource(bridge))) {
                        ast_channel_hangupsource_set(bridge, source);
                }
                ast_channel_unlock(bridge);
        }
}

int ast_channel_has_audio_frame_or_monitor(struct ast_channel *chan)
{
        return ast_channel_monitor(chan)
                || !ast_audiohook_write_list_empty(ast_channel_audiohooks(chan))
                || !ast_framehook_list_contains_no_active(ast_channel_framehooks(chan));
}

int ast_channel_has_hook_requiring_audio(struct ast_channel *chan)
{
        return ast_channel_monitor(chan)
                || !ast_audiohook_write_list_empty(ast_channel_audiohooks(chan))
                || !ast_framehook_list_contains_no_active_of_type(ast_channel_framehooks(chan), AST_FRAME_VOICE);
}

static void destroy_hooks(struct ast_channel *chan)
{
        if (ast_channel_audiohooks(chan)) {
                ast_audiohook_detach_list(ast_channel_audiohooks(chan));
                ast_channel_audiohooks_set(chan, NULL);
        }

        ast_framehook_list_destroy(chan);
}

/*! \brief Hangup a channel */
void ast_hangup(struct ast_channel *chan)
{
        /* Be NULL safe for RAII_VAR() usage. */
        if (!chan) {
                return;
        }

        ast_autoservice_stop(chan);

        ast_channel_lock(chan);

        while (ast_channel_masq(chan) || ast_channel_masqr(chan))  {
                CHANNEL_DEADLOCK_AVOIDANCE(chan);
        }

        /* Mark as a zombie so a masquerade cannot be setup on this channel. */
        ast_set_flag(ast_channel_flags(chan), AST_FLAG_ZOMBIE);

        ast_channel_unlock(chan);

        /*
         * XXX if running the hangup handlers here causes problems
         * because the handlers take too long to execute, we could move
         * the meat of this function into another thread.  A thread
         * where channels go to die.
         *
         * If this is done, ast_autoservice_chan_hangup_peer() will no
         * longer be needed.
         */
        ast_pbx_hangup_handler_run(chan);
        ao2_unlink(channels, chan);
        ast_channel_lock(chan);

        destroy_hooks(chan);

        free_translation(chan);
        /* Close audio stream */
        if (ast_channel_stream(chan)) {
                ast_closestream(ast_channel_stream(chan));
                ast_channel_stream_set(chan, NULL);
        }
        /* Close video stream */
        if (ast_channel_vstream(chan)) {
                ast_closestream(ast_channel_vstream(chan));
                ast_channel_vstream_set(chan, NULL);
        }
        if (ast_channel_sched(chan)) {
                ast_sched_context_destroy(ast_channel_sched(chan));
                ast_channel_sched_set(chan, NULL);
        }

        if (ast_channel_generatordata(chan)) {  /* Clear any tone stuff remaining */
                if (ast_channel_generator(chan) && ast_channel_generator(chan)->release) {
                        ast_channel_generator(chan)->release(chan, ast_channel_generatordata(chan));
                }
        }
        ast_channel_generatordata_set(chan, NULL);
        ast_channel_generator_set(chan, NULL);

        if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING)) {
                ast_log(LOG_WARNING, "Hard hangup called by thread %ld on %s, while fd "
                        "is blocked by thread %ld in procedure %s!  Expect a failure\n",
                        (long) pthread_self(), ast_channel_name(chan), (long)ast_channel_blocker(chan), ast_channel_blockproc(chan));
                ast_assert(ast_test_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING) == 0);
        }

        ast_debug(1, "Hanging up channel '%s'\n", ast_channel_name(chan));
        if (ast_channel_tech(chan)->hangup) {
                ast_channel_tech(chan)->hangup(chan);
        }

        ast_channel_unlock(chan);

        ast_cc_offer(chan);

        ast_channel_unref(chan);
}

/*!
 * \internal
 * \brief Set channel answered time if not already set.
 * \since 13.11.0
 *
 * \param chan Channel to set answered time.
 *
 * \return Nothing
 */
static void set_channel_answer_time(struct ast_channel *chan)
{
        if (ast_tvzero(ast_channel_answertime(chan))) {
                struct timeval answertime;

                answertime = ast_tvnow();
                ast_channel_answertime_set(chan, &answertime);
        }
}

int ast_raw_answer(struct ast_channel *chan)
{
        int res = 0;

        ast_channel_lock(chan);

        /* You can't answer an outbound call */
        if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_OUTGOING)) {
                ast_channel_unlock(chan);
                return 0;
        }

        /* Stop if we're a zombie or need a soft hangup */
        if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_ZOMBIE) || ast_check_hangup(chan)) {
                ast_channel_unlock(chan);
                return -1;
        }

        /*
         * Mark when incoming channel answered so we can know how
         * long the channel has been up.
         */
        set_channel_answer_time(chan);

        ast_channel_unlock(chan);

        switch (ast_channel_state(chan)) {
        case AST_STATE_RINGING:
        case AST_STATE_RING:
                ast_channel_lock(chan);
                if (ast_channel_tech(chan)->answer) {
                        res = ast_channel_tech(chan)->answer(chan);
                }
                ast_setstate(chan, AST_STATE_UP);
                ast_channel_unlock(chan);
                break;
        case AST_STATE_UP:
                break;
        default:
                break;
        }

        ast_indicate(chan, -1);

        return res;
}

int __ast_answer(struct ast_channel *chan, unsigned int delay)
{
        int res = 0;
        enum ast_channel_state old_state;

        old_state = ast_channel_state(chan);
        if ((res = ast_raw_answer(chan))) {
                return res;
        }

        switch (old_state) {
        case AST_STATE_RINGING:
        case AST_STATE_RING:
                /* wait for media to start flowing, but don't wait any longer
                 * than 'delay' or 500 milliseconds, whichever is longer
                 */
                do {
                        AST_LIST_HEAD_NOLOCK(, ast_frame) frames;
                        struct ast_frame *cur;
                        struct ast_frame *new_frame;
                        int timeout_ms = MAX(delay, 500);
                        unsigned int done = 0;
                        struct timeval start;

                        AST_LIST_HEAD_INIT_NOLOCK(&frames);

                        start = ast_tvnow();
                        for (;;) {
                                int ms = ast_remaining_ms(start, timeout_ms);
                                ms = ast_waitfor(chan, ms);
                                if (ms < 0) {
                                        ast_log(LOG_WARNING, "Error condition occurred when polling channel %s for a voice frame: %s\n", ast_channel_name(chan), strerror(errno));
                                        res = -1;
                                        break;
                                }
                                if (ms == 0) {
                                        ast_debug(2, "Didn't receive a media frame from %s within %u ms of answering. Continuing anyway\n", ast_channel_name(chan), MAX(delay, 500));
                                        break;
                                }
                                cur = ast_read(chan);
                                if (!cur || ((cur->frametype == AST_FRAME_CONTROL) &&
                                             (cur->subclass.integer == AST_CONTROL_HANGUP))) {
                                        if (cur) {
                                                ast_frfree(cur);
                                        }
                                        res = -1;
                                        ast_debug(2, "Hangup of channel %s detected in answer routine\n", ast_channel_name(chan));
                                        break;
                                }

                                if ((new_frame = ast_frisolate(cur)) != cur) {
                                        ast_frfree(cur);
                                }

                                AST_LIST_INSERT_HEAD(&frames, new_frame, frame_list);

                                /* if a specific delay period was requested, continue
                                 * until that delay has passed. don't stop just because
                                 * incoming media has arrived.
                                 */
                                if (delay) {
                                        continue;
                                }

                                switch (new_frame->frametype) {
                                        /* all of these frametypes qualify as 'media' */
                                case AST_FRAME_VOICE:
                                case AST_FRAME_VIDEO:
                                case AST_FRAME_TEXT:
                                case AST_FRAME_DTMF_BEGIN:
                                case AST_FRAME_DTMF_END:
                                case AST_FRAME_IMAGE:
                                case AST_FRAME_HTML:
                                case AST_FRAME_MODEM:
                                case AST_FRAME_RTCP:
                                        done = 1;
                                        break;
                                case AST_FRAME_CONTROL:
                                case AST_FRAME_IAX:
                                case AST_FRAME_BRIDGE_ACTION:
                                case AST_FRAME_BRIDGE_ACTION_SYNC:
                                case AST_FRAME_NULL:
                                case AST_FRAME_CNG:
                                        break;
                                }

                                if (done) {
                                        break;
                                }
                        }

                        ast_channel_lock(chan);
                        while ((cur = AST_LIST_REMOVE_HEAD(&frames, frame_list))) {
                                if (res == 0) {
                                        ast_queue_frame_head(chan, cur);
                                }
                                ast_frfree(cur);
                        }
                        ast_channel_unlock(chan);
                } while (0);
                break;
        default:
                break;
        }

        return res;
}

int ast_answer(struct ast_channel *chan)
{
        return __ast_answer(chan, 0);
}

inline int ast_auto_answer(struct ast_channel *chan)
{
        if (ast_channel_state(chan) == AST_STATE_UP) {
                /* Already answered */
                return 0;
        }
        return ast_answer(chan);
}

int ast_channel_get_duration(struct ast_channel *chan)
{
        ast_assert(NULL != chan);

        if (ast_tvzero(ast_channel_creationtime(chan))) {
                return 0;
        }
        return (ast_tvdiff_ms(ast_tvnow(), ast_channel_creationtime(chan)) / 1000);
}

int ast_channel_get_up_time(struct ast_channel *chan)
{
        ast_assert(NULL != chan);

        if (ast_tvzero(ast_channel_answertime(chan))) {
                return 0;
        }
        return (ast_tvdiff_ms(ast_tvnow(), ast_channel_answertime(chan)) / 1000);
}

static void deactivate_generator_nolock(struct ast_channel *chan)
{
        if (ast_channel_generatordata(chan)) {
                struct ast_generator *generator = ast_channel_generator(chan);

                if (generator && generator->release) {
                        generator->release(chan, ast_channel_generatordata(chan));
                }
                ast_channel_generatordata_set(chan, NULL);
                ast_channel_generator_set(chan, NULL);
                ast_channel_set_fd(chan, AST_GENERATOR_FD, -1);
                ast_clear_flag(ast_channel_flags(chan), AST_FLAG_WRITE_INT);
                ast_settimeout(chan, 0, NULL, NULL);
        }
}

void ast_deactivate_generator(struct ast_channel *chan)
{
        ast_channel_lock(chan);
        deactivate_generator_nolock(chan);
        ast_channel_unlock(chan);
}

static void generator_write_format_change(struct ast_channel *chan)
{
        struct ast_generator *generator;

        ast_channel_lock(chan);
        generator = ast_channel_generator(chan);
        if (generator && generator->write_format_change) {
                generator->write_format_change(chan, ast_channel_generatordata(chan));
        }
        ast_channel_unlock(chan);
}

static int generator_force(const void *data)
{
        /* Called if generator doesn't have data */
        void *tmp;
        int res;
        int (*generate)(struct ast_channel *chan, void *tmp, int datalen, int samples) = NULL;
        struct ast_channel *chan = (struct ast_channel *)data;

        ast_channel_lock(chan);
        tmp = ast_channel_generatordata(chan);
        ast_channel_generatordata_set(chan, NULL);
        if (ast_channel_generator(chan))
                generate = ast_channel_generator(chan)->generate;
        ast_channel_unlock(chan);

        if (!tmp || !generate) {
                return 0;
        }

        res = generate(chan, tmp, 0, ast_format_get_sample_rate(ast_channel_writeformat(chan)) / 50);

        ast_channel_lock(chan);
        if (ast_channel_generator(chan) && generate == ast_channel_generator(chan)->generate) {
                ast_channel_generatordata_set(chan, tmp);
        }
        ast_channel_unlock(chan);

        if (res) {
                ast_debug(1, "Auto-deactivating generator\n");
                ast_deactivate_generator(chan);
        }

        return 0;
}

int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params)
{
        int res = 0;
        void *generatordata = NULL;

        ast_channel_lock(chan);
        if (ast_channel_generatordata(chan)) {
                struct ast_generator *generator_old = ast_channel_generator(chan);

                if (generator_old && generator_old->release) {
                        generator_old->release(chan, ast_channel_generatordata(chan));
                }
        }
        if (gen->alloc && !(generatordata = gen->alloc(chan, params))) {
                res = -1;
        }
        ast_channel_generatordata_set(chan, generatordata);
        if (!res) {
                ast_settimeout(chan, 50, generator_force, chan);
                ast_channel_generator_set(chan, gen);
        }
        ast_channel_unlock(chan);

        ast_prod(chan);

        return res;
}

/*! \brief Wait for x amount of time on a file descriptor to have input.  */
int ast_waitfor_n_fd(int *fds, int n, int *ms, int *exception)
{
        int winner = -1;
        ast_waitfor_nandfds(NULL, 0, fds, n, exception, &winner, ms);
        return winner;
}

/*! \brief Wait for x amount of time on a file descriptor to have input.  */
#ifdef HAVE_EPOLL
static struct ast_channel *ast_waitfor_nandfds_classic(struct ast_channel **c, int n, int *fds, int nfds,
                                        int *exception, int *outfd, int *ms)
#else
struct ast_channel *ast_waitfor_nandfds(struct ast_channel **c, int n, int *fds, int nfds,
                                        int *exception, int *outfd, int *ms)
#endif
{
        struct timeval start = { 0 , 0 };
        struct pollfd *pfds = NULL;
        int res;
        long rms;
        int x, y, max;
        int sz;
        struct timeval now = { 0, 0 };
        struct timeval whentohangup = { 0, 0 }, diff;
        struct ast_channel *winner = NULL;
        struct fdmap {
                int chan;
                int fdno;
        } *fdmap = NULL;

        if (outfd) {
                *outfd = -99999;
        }
        if (exception) {
                *exception = 0;
        }

        if ((sz = n * AST_MAX_FDS + nfds)) {
                pfds = ast_alloca(sizeof(*pfds) * sz);
                fdmap = ast_alloca(sizeof(*fdmap) * sz);
        } else {
                /* nothing to allocate and no FDs to check */
                return NULL;
        }

        for (x = 0; x < n; x++) {
                ast_channel_lock(c[x]);
                if (!ast_tvzero(*ast_channel_whentohangup(c[x]))) {
                        if (ast_tvzero(whentohangup))
                                now = ast_tvnow();
                        diff = ast_tvsub(*ast_channel_whentohangup(c[x]), now);
                        if (diff.tv_sec < 0 || ast_tvzero(diff)) {
                                ast_test_suite_event_notify("HANGUP_TIME", "Channel: %s", ast_channel_name(c[x]));
                                /* Should already be hungup */
                                ast_channel_softhangup_internal_flag_add(c[x], AST_SOFTHANGUP_TIMEOUT);
                                ast_channel_unlock(c[x]);
                                return c[x];
                        }
                        if (ast_tvzero(whentohangup) || ast_tvcmp(diff, whentohangup) < 0)
                                whentohangup = diff;
                }
                ast_channel_unlock(c[x]);
        }
        /* Wait full interval */
        rms = *ms;
        /* INT_MAX, not LONG_MAX, because it matters on 64-bit */
        if (!ast_tvzero(whentohangup) && whentohangup.tv_sec < INT_MAX / 1000) {
                rms = whentohangup.tv_sec * 1000 + whentohangup.tv_usec / 1000;              /* timeout in milliseconds */
                if (*ms >= 0 && *ms < rms) {                                                 /* original *ms still smaller */
                        rms =  *ms;
                }
        } else if (!ast_tvzero(whentohangup) && rms < 0) {
                /* Tiny corner case... call would need to last >24 days */
                rms = INT_MAX;
        }
        /*
         * Build the pollfd array, putting the channels' fds first,
         * followed by individual fds. Order is important because
         * individual fd's must have priority over channel fds.
         */
        max = 0;
        for (x = 0; x < n; x++) {
                for (y = 0; y < AST_MAX_FDS; y++) {
                        fdmap[max].fdno = y;  /* fd y is linked to this pfds */
                        fdmap[max].chan = x;  /* channel x is linked to this pfds */
                        max += ast_add_fd(&pfds[max], ast_channel_fd(c[x], y));
                }
                ast_channel_lock(c[x]);
                CHECK_BLOCKING(c[x]);
                ast_channel_unlock(c[x]);
        }
        /* Add the individual fds */
        for (x = 0; x < nfds; x++) {
                fdmap[max].chan = -1;
                max += ast_add_fd(&pfds[max], fds[x]);
        }

        if (*ms > 0) {
                start = ast_tvnow();
        }

        if (sizeof(int) == 4) { /* XXX fix timeout > 600000 on linux x86-32 */
                do {
                        int kbrms = rms;
                        if (kbrms > 600000) {
                                kbrms = 600000;
                        }
                        res = ast_poll(pfds, max, kbrms);
                        if (!res) {
                                rms -= kbrms;
                        }
                } while (!res && (rms > 0));
        } else {
                res = ast_poll(pfds, max, rms);
        }
        for (x = 0; x < n; x++) {
                ast_channel_lock(c[x]);
                ast_clear_flag(ast_channel_flags(c[x]), AST_FLAG_BLOCKING);
                ast_channel_unlock(c[x]);
        }
        if (res < 0) { /* Simulate a timeout if we were interrupted */
                if (errno != EINTR) {
                        *ms = -1;
                }
                return NULL;
        }
        if (!ast_tvzero(whentohangup)) {   /* if we have a timeout, check who expired */
                now = ast_tvnow();
                for (x = 0; x < n; x++) {
                        if (!ast_tvzero(*ast_channel_whentohangup(c[x])) && ast_tvcmp(*ast_channel_whentohangup(c[x]), now) <= 0) {
                                ast_test_suite_event_notify("HANGUP_TIME", "Channel: %s", ast_channel_name(c[x]));
                                ast_channel_softhangup_internal_flag_add(c[x], AST_SOFTHANGUP_TIMEOUT);
                                if (winner == NULL) {
                                        winner = c[x];
                                }
                        }
                }
        }
        if (res == 0) { /* no fd ready, reset timeout and done */
                *ms = 0;        /* XXX use 0 since we may not have an exact timeout. */
                return winner;
        }
        /*
         * Then check if any channel or fd has a pending event.
         * Remember to check channels first and fds last, as they
         * must have priority on setting 'winner'
         */
        for (x = 0; x < max; x++) {
                res = pfds[x].revents;
                if (res == 0) {
                        continue;
                }
                if (fdmap[x].chan >= 0) {       /* this is a channel */
                        winner = c[fdmap[x].chan];      /* override previous winners */
                        ast_channel_lock(winner);
                        if (res & POLLPRI) {
                                ast_set_flag(ast_channel_flags(winner), AST_FLAG_EXCEPTION);
                        } else {
                                ast_clear_flag(ast_channel_flags(winner), AST_FLAG_EXCEPTION);
                        }
                        ast_channel_fdno_set(winner, fdmap[x].fdno);
                        ast_channel_unlock(winner);
                } else {                        /* this is an fd */
                        if (outfd) {
                                *outfd = pfds[x].fd;
                        }
                        if (exception) {
                                *exception = (res & POLLPRI) ? -1 : 0;
                        }
                        winner = NULL;
                }
        }
        if (*ms > 0) {
                *ms -= ast_tvdiff_ms(ast_tvnow(), start);
                if (*ms < 0) {
                        *ms = 0;
                }
        }
        return winner;
}

#ifdef HAVE_EPOLL
static struct ast_channel *ast_waitfor_nandfds_simple(struct ast_channel *chan, int *ms)
{
        struct timeval start = { 0 , 0 };
        int res = 0;
        struct epoll_event ev[1];
        long diff, rms = *ms;
        struct ast_channel *winner = NULL;
        struct ast_epoll_data *aed = NULL;

        ast_channel_lock(chan);
        /* Figure out their timeout */
        if (!ast_tvzero(*ast_channel_whentohangup(chan))) {
                if ((diff = ast_tvdiff_ms(*ast_channel_whentohangup(chan), ast_tvnow())) < 0) {
                        /* They should already be hungup! */
                        ast_channel_softhangup_internal_flag_add(chan, AST_SOFTHANGUP_TIMEOUT);
                        ast_channel_unlock(chan);
                        return NULL;
                }
                /* If this value is smaller then the current one... make it priority */
                if (rms > diff) {
                        rms = diff;
                }
        }

        ast_channel_unlock(chan);

        /* Time to make this channel block... */
        CHECK_BLOCKING(chan);

        if (*ms > 0) {
                start = ast_tvnow();
        }

        /* We don't have to add any file descriptors... they are already added, we just have to wait! */
        res = epoll_wait(ast_channel_epfd(chan), ev, 1, rms);

        /* Stop blocking */
        ast_clear_flag(ast_channel_flags(chan), AST_FLAG_BLOCKING);

        /* Simulate a timeout if we were interrupted */
        if (res < 0) {
                if (errno != EINTR) {
                        *ms = -1;
                }
                return NULL;
        }

        /* If this channel has a timeout see if it expired */
        if (!ast_tvzero(*ast_channel_whentohangup(chan))) {
                if (ast_tvdiff_ms(ast_tvnow(), *ast_channel_whentohangup(chan)) >= 0) {
                        ast_channel_softhangup_internal_flag_add(chan, AST_SOFTHANGUP_TIMEOUT);
                        winner = chan;
                }
        }

        /* No fd ready, reset timeout and be done for now */
        if (!res) {
                *ms = 0;
                return winner;
        }

        /* See what events are pending */
        aed = ev[0].data.ptr;
        ast_channel_fdno_set(chan, aed->which);
        if (ev[0].events & EPOLLPRI) {
                ast_set_flag(ast_channel_flags(chan), AST_FLAG_EXCEPTION);
        } else {
                ast_clear_flag(ast_channel_flags(chan), AST_FLAG_EXCEPTION);
        }

        if (*ms > 0) {
                *ms -= ast_tvdiff_ms(ast_tvnow(), start);
                if (*ms < 0) {
                        *ms = 0;
                }
        }

        return chan;
}

static struct ast_channel *ast_waitfor_nandfds_complex(struct ast_channel **c, int n, int *ms)
{
        struct timeval start = { 0 , 0 };
        int res = 0, i;
        struct epoll_event ev[25] = { { 0, } };
        struct timeval now = { 0, 0 };
        long whentohangup = 0, diff = 0, rms = *ms;
        struct ast_channel *winner = NULL;

        for (i = 0; i < n; i++) {
                ast_channel_lock(c[i]);
                if (!ast_tvzero(*ast_channel_whentohangup(c[i]))) {
                        if (whentohangup == 0) {
                                now = ast_tvnow();
                        }
                        if ((diff = ast_tvdiff_ms(*ast_channel_whentohangup(c[i]), now)) < 0) {
                                ast_channel_softhangup_internal_flag_add(c[i], AST_SOFTHANGUP_TIMEOUT);
                                ast_channel_unlock(c[i]);
                                return c[i];
                        }
                        if (!whentohangup || whentohangup > diff) {
                                whentohangup = diff;
                        }
                }
                ast_channel_unlock(c[i]);
                CHECK_BLOCKING(c[i]);
        }

        rms = *ms;
        if (whentohangup) {
                rms = whentohangup;
                if (*ms >= 0 && *ms < rms) {
                        rms = *ms;
                }
        }

        if (*ms > 0) {
                start = ast_tvnow();
        }

        res = epoll_wait(ast_channel_epfd(c[0]), ev, 25, rms);

        for (i = 0; i < n; i++) {
                ast_clear_flag(ast_channel_flags(c[i]), AST_FLAG_BLOCKING);
        }

        if (res < 0) {
                if (errno != EINTR) {
                        *ms = -1;
                }
                return NULL;
        }

        if (whentohangup) {
                now = ast_tvnow();
                for (i = 0; i < n; i++) {
                        if (!ast_tvzero(*ast_channel_whentohangup(c[i])) && ast_tvdiff_ms(now, *ast_channel_whentohangup(c[i])) >= 0) {
                                ast_channel_softhangup_internal_flag_add(c[i], AST_SOFTHANGUP_TIMEOUT);
                                if (!winner) {
                                        winner = c[i];
                                }
                        }
                }
        }

        if (!res) {
                *ms = 0;
                return winner;
        }

        for (i = 0; i < res; i++) {
                struct ast_epoll_data *aed = ev[i].data.ptr;

                if (!ev[i].events || !aed) {
                        continue;
                }

                winner = aed->chan;
                if (ev[i].events & EPOLLPRI) {
                        ast_set_flag(ast_channel_flags(winner), AST_FLAG_EXCEPTION);
                } else {
                        ast_clear_flag(ast_channel_flags(winner), AST_FLAG_EXCEPTION);
                }
                ast_channel_fdno_set(winner, aed->which);
        }

        if (*ms > 0) {
                *ms -= ast_tvdiff_ms(ast_tvnow(), start);
                if (*ms < 0) {
                        *ms = 0;
                }
        }

        return winner;
}

struct ast_channel *ast_waitfor_nandfds(struct ast_channel **c, int n, int *fds, int nfds,
                                        int *exception, int *outfd, int *ms)
{
        /* Clear all provided values in one place. */
        if (outfd) {
                *outfd = -99999;
        }
        if (exception) {
                *exception = 0;
        }

        /* If no epoll file descriptor is available resort to classic nandfds */
        if (!n || nfds || ast_channel_epfd(c[0]) == -1) {
                return ast_waitfor_nandfds_classic(c, n, fds, nfds, exception, outfd, ms);
        } else if (!nfds && n == 1) {
                return ast_waitfor_nandfds_simple(c[0], ms);
        } else {
                return ast_waitfor_nandfds_complex(c, n, ms);
        }
}
#endif

struct ast_channel *ast_waitfor_n(struct ast_channel **c, int n, int *ms)
{
        return ast_waitfor_nandfds(c, n, NULL, 0, NULL, NULL, ms);
}

int ast_waitfor(struct ast_channel *c, int ms)
{
        if (ms < 0) {
                do {
                        ms = 100000;
                        ast_waitfor_nandfds(&c, 1, NULL, 0, NULL, NULL, &ms);
                } while (!ms);
        } else {
                ast_waitfor_nandfds(&c, 1, NULL, 0, NULL, NULL, &ms);
        }
        return ms;
}

int ast_waitfordigit(struct ast_channel *c, int ms)
{
        return ast_waitfordigit_full(c, ms, -1, -1);
}

int ast_settimeout(struct ast_channel *c, unsigned int rate, int (*func)(const void *data), void *data)
{
        return ast_settimeout_full(c, rate, func, data, 0);
}

int ast_settimeout_full(struct ast_channel *c, unsigned int rate, int (*func)(const void *data), void *data, unsigned int is_ao2_obj)
{
        int res;
        unsigned int real_rate = rate, max_rate;

        ast_channel_lock(c);

        if (ast_channel_timingfd(c) == -1) {
                ast_channel_unlock(c);
                return -1;
        }

        if (!func) {
                rate = 0;
                data = NULL;
        }

        if (rate && rate > (max_rate = ast_timer_get_max_rate(ast_channel_timer(c)))) {
                real_rate = max_rate;
        }

        ast_debug(1, "Scheduling timer at (%u requested / %u actual) timer ticks per second\n", rate, real_rate);

        res = ast_timer_set_rate(ast_channel_timer(c), real_rate);

        if (ast_channel_timingdata(c) && ast_test_flag(ast_channel_flags(c), AST_FLAG_TIMINGDATA_IS_AO2_OBJ)) {
                ao2_ref(ast_channel_timingdata(c), -1);
        }

        ast_channel_timingfunc_set(c, func);
        ast_channel_timingdata_set(c, data);

        if (data && is_ao2_obj) {
                ao2_ref(data, 1);
                ast_set_flag(ast_channel_flags(c), AST_FLAG_TIMINGDATA_IS_AO2_OBJ);
        } else {
                ast_clear_flag(ast_channel_flags(c), AST_FLAG_TIMINGDATA_IS_AO2_OBJ);
        }

        if (func == NULL && rate == 0 && ast_channel_fdno(c) == AST_TIMING_FD) {
                /* Clearing the timing func and setting the rate to 0
                 * means that we don't want to be reading from the timingfd
                 * any more. Setting c->fdno to -1 means we won't have any
                 * errant reads from the timingfd, meaning we won't potentially
                 * miss any important frames.
                 */
                ast_channel_fdno_set(c, -1);
        }

        ast_channel_unlock(c);

        return res;
}

int ast_waitfordigit_full(struct ast_channel *c, int timeout_ms, int audiofd, int cmdfd)
{
        struct timeval start = ast_tvnow();
        int ms;

        /* Stop if we're a zombie or need a soft hangup */
        if (ast_test_flag(ast_channel_flags(c), AST_FLAG_ZOMBIE) || ast_check_hangup(c))
                return -1;

        /* Only look for the end of DTMF, don't bother with the beginning and don't emulate things */
        ast_set_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);

        /* Wait for a digit, no more than timeout_ms milliseconds total.
         * Or, wait indefinitely if timeout_ms is <0.
         */
        while ((ms = ast_remaining_ms(start, timeout_ms))) {
                struct ast_channel *rchan;
                int outfd = -1;

                errno = 0;
                /* While ast_waitfor_nandfds tries to help by reducing the timeout by how much was waited,
                 * it is unhelpful if it waited less than a millisecond.
                 */
                rchan = ast_waitfor_nandfds(&c, 1, &cmdfd, (cmdfd > -1) ? 1 : 0, NULL, &outfd, &ms);

                if (!rchan && outfd < 0 && ms) {
                        if (errno == 0 || errno == EINTR)
                                continue;
                        ast_log(LOG_WARNING, "Wait failed (%s)\n", strerror(errno));
                        ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
                        return -1;
                } else if (outfd > -1) {
                        /* The FD we were watching has something waiting */
                        ast_log(LOG_WARNING, "The FD we were waiting for has something waiting. Waitfordigit returning numeric 1\n");
                        ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
                        return 1;
                } else if (rchan) {
                        int res;
                        struct ast_frame *f = ast_read(c);
                        if (!f)
                                return -1;

                        switch (f->frametype) {
                        case AST_FRAME_DTMF_BEGIN:
                                break;
                        case AST_FRAME_DTMF_END:
                                res = f->subclass.integer;
                                ast_frfree(f);
                                ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
                                return res;
                        case AST_FRAME_CONTROL:
                                switch (f->subclass.integer) {
                                case AST_CONTROL_HANGUP:
                                        ast_frfree(f);
                                        ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
                                        return -1;
                                case AST_CONTROL_STREAM_STOP:
                                case AST_CONTROL_STREAM_SUSPEND:
                                case AST_CONTROL_STREAM_RESTART:
                                case AST_CONTROL_STREAM_REVERSE:
                                case AST_CONTROL_STREAM_FORWARD:
                                        /* Fall-through and treat as if it were a DTMF signal. Items
                                         * that perform stream control will handle this. */
                                        res = f->subclass.integer;
                                        ast_frfree(f);
                                        ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
                                        return res;
                                case AST_CONTROL_PVT_CAUSE_CODE:
                                case AST_CONTROL_RINGING:
                                case AST_CONTROL_ANSWER:
                                case AST_CONTROL_SRCUPDATE:
                                case AST_CONTROL_SRCCHANGE:
                                case AST_CONTROL_CONNECTED_LINE:
                                case AST_CONTROL_REDIRECTING:
                                case AST_CONTROL_UPDATE_RTP_PEER:
                                case AST_CONTROL_HOLD:
                                case AST_CONTROL_UNHOLD:
                                case -1:
                                        /* Unimportant */
                                        break;
                                default:
                                        ast_log(LOG_WARNING, "Unexpected control subclass '%d'\n", f->subclass.integer);
                                        break;
                                }
                                break;
                        case AST_FRAME_VOICE:
                                /* Write audio if appropriate */
                                if (audiofd > -1) {
                                        if (write(audiofd, f->data.ptr, f->datalen) < 0) {
                                                ast_log(LOG_WARNING, "write() failed: %s\n", strerror(errno));
                                        }
                                }
                        default:
                                /* Ignore */
                                break;
                        }
                        ast_frfree(f);
                }
        }

        ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);

        return 0; /* Time is up */
}

enum DtmfDirection {
        DTMF_RECEIVED,
        DTMF_SENT
};

static const char *dtmf_direction_to_string(enum DtmfDirection direction)
{
        switch (direction) {
        case DTMF_RECEIVED:
                return "Received";
        case DTMF_SENT:
                return "Sent";
        }

        return "?";
}

static void send_dtmf_begin_event(struct ast_channel *chan,
        enum DtmfDirection direction, const char digit)
{
        RAII_VAR(struct ast_json *, blob, NULL, ast_json_unref);
        char digit_str[] = { digit, '\0' };

        blob = ast_json_pack("{ s: s, s: s }",
                "digit", digit_str,
                "direction", dtmf_direction_to_string(direction));
        if (!blob) {
                return;
        }

        ast_channel_publish_cached_blob(chan, ast_channel_dtmf_begin_type(), blob);
}

static void send_dtmf_end_event(struct ast_channel *chan,
        enum DtmfDirection direction, const char digit, long duration_ms)
{
        RAII_VAR(struct ast_json *, blob, NULL, ast_json_unref);
        char digit_str[] = { digit, '\0' };

        blob = ast_json_pack("{ s: s, s: s, s: i }",
                "digit", digit_str,
                "direction", dtmf_direction_to_string(direction),
                "duration_ms", duration_ms);
        if (!blob) {
                return;
        }

        ast_channel_publish_cached_blob(chan, ast_channel_dtmf_end_type(), blob);
}

static void ast_read_generator_actions(struct ast_channel *chan, struct ast_frame *f)
{
        struct ast_generator *generator;
        void *gendata;
        int res;
        int samples;

        generator = ast_channel_generator(chan);
        if (!generator
                || !generator->generate
                || f->frametype != AST_FRAME_VOICE
                || !ast_channel_generatordata(chan)
                || ast_channel_timingfunc(chan)) {
                return;
        }

        /*
         * We must generate frames in phase locked mode since
         * we have no internal timer available.
         */
        if (ast_format_cmp(f->subclass.format, ast_channel_writeformat(chan)) == AST_FORMAT_CMP_NOT_EQUAL) {
                float factor;
                factor = ((float) ast_format_get_sample_rate(ast_channel_writeformat(chan))) / ((float) ast_format_get_sample_rate(f->subclass.format));
                samples = (int) (((float) f->samples) * factor);
        } else {
                samples = f->samples;
        }

        gendata = ast_channel_generatordata(chan);
        ast_channel_generatordata_set(chan, NULL);     /* reset, to let writes go through */

        /*
         * This unlock is here based on two assumptions that hold true at
         * this point in the code. 1) this function is only called from
         * within __ast_read() and 2) all generators call ast_write() in
         * their generate callback.
         *
         * The reason this is added is so that when ast_write is called,
         * the lock that occurs there will not recursively lock the
         * channel.  Doing this will allow deadlock avoidance to work in
         * deeper functions.
         */
        ast_channel_unlock(chan);
        res = generator->generate(chan, gendata, f->datalen, samples);
        ast_channel_lock(chan);
        if (generator == ast_channel_generator(chan)) {
                ast_channel_generatordata_set(chan, gendata);
                if (res) {
                        ast_debug(1, "Auto-deactivating generator\n");
                        ast_deactivate_generator(chan);
                }
        }
}

static inline void queue_dtmf_readq(struct ast_channel *chan, struct ast_frame *f)
{
        struct ast_frame *fr = ast_channel_dtmff(chan);

        fr->frametype = AST_FRAME_DTMF_END;
        fr->subclass.integer = f->subclass.integer;
        fr->len = f->len;

        /* The only time this function will be called is for a frame that just came
         * out of the channel driver.  So, we want to stick it on the tail of the
         * readq. */

        ast_queue_frame(chan, fr);
}

/*!
 * \brief Determine whether or not we should ignore DTMF in the readq
 */
static inline int should_skip_dtmf(struct ast_channel *chan)
{
        if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_DEFER_DTMF | AST_FLAG_EMULATE_DTMF)) {
                /* We're in the middle of emulating a digit, or DTMF has been
                 * explicitly deferred.  Skip this digit, then. */
                return 1;
        }

        if (!ast_tvzero(*ast_channel_dtmf_tv(chan)) &&
                        ast_tvdiff_ms(ast_tvnow(), *ast_channel_dtmf_tv(chan)) < AST_MIN_DTMF_GAP) {
                /* We're not in the middle of a digit, but it hasn't been long enough
                 * since the last digit, so we'll have to skip DTMF for now. */
                return 1;
        }

        return 0;
}

/*!
 * \brief calculates the number of samples to jump forward with in a monitor stream.

 * \note When using ast_seekstream() with the read and write streams of a monitor,
 * the number of samples to seek forward must be of the same sample rate as the stream
 * or else the jump will not be calculated correctly.
 *
 * \retval number of samples to seek forward after rate conversion.
 */
static inline int calc_monitor_jump(int samples, int sample_rate, int seek_rate)
{
        int diff = sample_rate - seek_rate;

        if (diff > 0) {
                samples = samples / (float) (sample_rate / seek_rate);
        } else if (diff < 0) {
                samples = samples * (float) (seek_rate / sample_rate);
        }

        return samples;
}

static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio, int dropnondefault)
{
        struct ast_frame *f = NULL;     /* the return value */
        int prestate;
        int cause = 0;
        struct ast_stream *stream = NULL, *default_stream = NULL;

        /* this function is very long so make sure there is only one return
         * point at the end (there are only two exceptions to this).
         */
        ast_channel_lock(chan);

        /* Stop if we're a zombie or need a soft hangup */
        if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_ZOMBIE) || ast_check_hangup(chan)) {
                if (ast_channel_generator(chan))
                        ast_deactivate_generator(chan);

                /*
                 * It is possible for chan->_softhangup to be set and there
                 * still be control frames that need to be read.  Instead of
                 * just going to 'done' in the case of ast_check_hangup(), we
                 * need to queue the end-of-Q frame so that it can mark the end
                 * of the read queue.  If there are frames to be read,
                 * ast_queue_control() will be called repeatedly, but will only
                 * queue the first end-of-Q frame.
                 */
                if (ast_channel_softhangup_internal_flag(chan)) {
                        ast_queue_control(chan, AST_CONTROL_END_OF_Q);
                } else {
                        goto done;
                }
        } else {
#ifdef AST_DEVMODE
                /*
                 * The ast_waitfor() code records which of the channel's file
                 * descriptors reported that data is available.  In theory,
                 * ast_read() should only be called after ast_waitfor() reports
                 * that a channel has data available for reading.  However,
                 * there still may be some edge cases throughout the code where
                 * ast_read() is called improperly.  This can potentially cause
                 * problems, so if this is a developer build, make a lot of
                 * noise if this happens so that it can be addressed.
                 *
                 * One of the potential problems is blocking on a dead channel.
                 */
                if (ast_channel_fdno(chan) == -1) {
                        ast_log(LOG_ERROR,
                                "ast_read() on chan '%s' called with no recorded file descriptor.\n",
                                ast_channel_name(chan));
                }
#endif
        }

        prestate = ast_channel_state(chan);

        if (ast_channel_timingfd(chan) > -1 && ast_channel_fdno(chan) == AST_TIMING_FD) {
                enum ast_timer_event res;

                ast_clear_flag(ast_channel_flags(chan), AST_FLAG_EXCEPTION);

                res = ast_timer_get_event(ast_channel_timer(chan));

                switch (res) {
                case AST_TIMING_EVENT_EXPIRED:
                        if (ast_timer_ack(ast_channel_timer(chan), 1) < 0) {
                                ast_log(LOG_ERROR, "Failed to acknoweldge timer in ast_read\n");
                                goto done;
                        }

                        if (ast_channel_timingfunc(chan)) {
                                /* save a copy of func/data before unlocking the channel */
                                ast_timing_func_t func = ast_channel_timingfunc(chan);
                                void *data = ast_channel_timingdata(chan);
                                int got_ref = 0;
                                if (data && ast_test_flag(ast_channel_flags(chan), AST_FLAG_TIMINGDATA_IS_AO2_OBJ)) {
                                        ao2_ref(data, 1);
                                        got_ref = 1;
                                }
                                ast_channel_fdno_set(chan, -1);
                                ast_channel_unlock(chan);
                                func(data);
                                if (got_ref) {
                                        ao2_ref(data, -1);
                                }
                        } else {
                                ast_timer_set_rate(ast_channel_timer(chan), 0);
                                ast_channel_fdno_set(chan, -1);
                                ast_channel_unlock(chan);
                        }

                        /* cannot 'goto done' because the channel is already unlocked */
                        return &ast_null_frame;

                case AST_TIMING_EVENT_CONTINUOUS:
                        if (AST_LIST_EMPTY(ast_channel_readq(chan)) ||
                                !AST_LIST_NEXT(AST_LIST_FIRST(ast_channel_readq(chan)), frame_list)) {
                                ast_timer_disable_continuous(ast_channel_timer(chan));
                        }
                        break;
                }

        } else if (ast_channel_fd_isset(chan, AST_GENERATOR_FD) && ast_channel_fdno(chan) == AST_GENERATOR_FD) {