channel.c

Go to the documentation of this file.

/*
 * 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/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"
#include "asterisk/message.h"
 
/*** DOCUMENTATION
 ***/
 
#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) */
 
/* 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 DTMF digit as a begin and end
 *  100ms */
#define AST_DEFAULT_EMULATE_DTMF_DURATION 100
 
/*! Default amount of time to use when emulating an MF digit as a begin and end
 *  55ms */
#define DEFAULT_EMULATE_MF_DURATION 55
 
#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);
 
/*! \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 wordlen;
 
    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)) {
            ast_cli_completion_add(ast_strdup(cl->tech->type));
        }
    }
    AST_RWLIST_UNLOCK(&backends);
 
    return NULL;
}
 
/*! \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;
}
 
/*! \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));
}
 
/*! \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;
}
 
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;
    size_t 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__((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);
 
    /*
     * 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);
 
    nativeformats = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);
    if (!nativeformats) {
        /*
         * 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);
 
    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);
 
    ast_debug(1, "Channel %p '%s' allocated\n", tmp, ast_channel_name(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);
 
    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_lock(chan);
    ast_channel_publish_blob(chan, ast_channel_hold_type(), blob);
    ast_channel_unlock(chan);
 
    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_lock(chan);
    ast_channel_publish_blob(chan, ast_channel_unhold_type(), NULL);
    ast_channel_unlock(chan);
 
    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 Queue an ANSWER control frame with topology */
int ast_queue_answer(struct ast_channel *chan, const struct ast_stream_topology *topology)
{
    struct ast_frame f = {
        AST_FRAME_CONTROL,
        .subclass.integer = AST_CONTROL_ANSWER,
        .subclass.topology = (struct ast_stream_topology *)topology,
    };
    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) {
        ast_channel_lock(chan);
        pre = ast_test_flag(ast_channel_flags(chan), AST_FLAG_DEFER_DTMF);
        ast_set_flag(ast_channel_flags(chan), AST_FLAG_DEFER_DTMF);
        ast_channel_unlock(chan);
    }
    return pre;
}
 
/*! \brief Unset defer DTMF flag on channel */
void ast_channel_undefer_dtmf(struct ast_channel *chan)
{
    if (chan) {
        ast_channel_clear_flag(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;
 
    if (ast_strlen_zero(l_name)) {
        /* We didn't have a name to search for so quit. */
        return NULL;
    }
 
    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;
    }
 
    /* 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_TEXT_DATA:
    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 */
static int safe_sleep_conditional(struct ast_channel *chan, int timeout_ms, int (*cond)(void*), void *data, unsigned int generate_silence)
{
    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 (generate_silence && 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;
}
 
int ast_safe_sleep_conditional(struct ast_channel *chan, int timeout_ms, int (*cond)(void*), void *data)
{
    return safe_sleep_conditional(chan, timeout_ms, cond, data, 1);
}
 
/*! \brief Wait, look for hangups */
int ast_safe_sleep(struct ast_channel *chan, int ms)
{
    return safe_sleep_conditional(chan, ms, NULL, NULL, 1);
}
 
int ast_safe_sleep_without_silence(struct ast_channel *chan, int ms)
{
    return safe_sleep_conditional(chan, ms, NULL, NULL, 0);
}
 
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;
    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;
 
    ast_debug(1, "Channel %p '%s' destroying\n", chan, ast_channel_name(chan));
 
    /* 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_final_snapshot(chan);
        ast_channel_unlock(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);
    }
    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);
}
 
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)
{
    ast_channel_internal_fd_set(chan, which, fd);
    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_debug(1, "Channel %p '%s' hanging up.  Refs: %d\n", chan, ast_channel_name(chan),
        ao2_ref(chan, 0));
 
    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 LWP %d on %s, while blocked by thread LWP %d in procedure %s!  Expect a failure\n",
            ast_get_tid(), ast_channel_name(chan), ast_channel_blocker_tid(chan),
            ast_channel_blockproc(chan));
        ast_assert(0);
    }
 
    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.
 */
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_with_stream_topology(struct ast_channel *chan, struct ast_stream_topology *topology)
{
    int res = 0;
    SCOPE_TRACE(1, "%s\n", ast_channel_name(chan));
 
    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_with_stream_topology) {
            res = ast_channel_tech(chan)->answer_with_stream_topology(chan, topology);
 
        } else 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_raw_answer(struct ast_channel *chan)
{
    return ast_raw_answer_with_stream_topology(chan, NULL);
}
 
int __ast_answer(struct ast_channel *chan, unsigned int delay)
{
    int res = 0;
    enum ast_channel_state old_state;
    SCOPE_TRACE(1, "%s\n", ast_channel_name(chan));
 
    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_TEXT_DATA:
                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)
{
    SCOPE_TRACE(1, "%s\n", ast_channel_name(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);
}
 
int64_t ast_channel_get_duration_ms(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));
}
 
int ast_channel_get_duration(struct ast_channel *chan)
{
    return (ast_channel_get_duration_ms(chan) / 1000);
}
 
int64_t ast_channel_get_up_time_ms(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));
}
 
int ast_channel_get_up_time(struct ast_channel *chan)
{
    return (ast_channel_get_up_time_ms(chan) / 1000);
}
 
/*!
 * \brief Determine whether or not we have to trigger dtmf emulating using 50 fps timer events
 * especially when no voice frames are received during dtmf processing (direct media or muted
 * sender case using SIP INFO)
 */
static inline int should_trigger_dtmf_emulating(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. Trigger dtmf with periodic 50 pfs timer events, then. */
        return 1;
    }
 
    if (!ast_tvzero(*ast_channel_dtmf_tv(chan)) &&
            ast_tvdiff_ms(ast_tvnow(), *ast_channel_dtmf_tv(chan)) < 2*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 trigger DTMF further on.
         * Using 2 times AST_MIN_DTMF_GAP to trigger readq reading for possible
         * buffered next dtmf event
         */
        return 1;
    }
 
    return 0;
}
 
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);
    if (should_trigger_dtmf_emulating(chan)) {
        /* if in the middle of dtmf emulation keep 50 tick per sec timer on rolling */
        ast_timer_set_rate(ast_channel_timer(chan), 50);
    }
    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.  */
struct ast_channel *ast_waitfor_nandfds(struct ast_channel **c, int n, int *fds, int nfds,
                    int *exception, int *outfd, int *ms)
{
    struct timeval start = { 0 , 0 };
    struct pollfd *pfds = NULL;
    int res;
    long rms;
    int x, y, max;
    int sz = nfds;
    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;
    }
 
    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;
        }
        sz += ast_channel_fd_count(c[x]);
        ast_channel_unlock(c[x]);
    }
 
    if (!sz) {
        return NULL;
    }
 
    pfds = ast_alloca(sizeof(*pfds) * sz);
    fdmap = ast_alloca(sizeof(*fdmap) * sz);
 
    /* 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++) {
        ast_channel_lock(c[x]);
        for (y = 0; y < ast_channel_fd_count(c[x]); 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));
        }
        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;
}
 
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, NULL, -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(3, "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, const char *breakon, 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_channel_set_flag(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_channel_clear_flag(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_channel_clear_flag(c, AST_FLAG_END_DTMF_ONLY);
            return 1;
        } else if (rchan) {
            int res;
            struct ast_frame *f = ast_read(c);
 
            if (!f) {
                ast_channel_clear_flag(c, AST_FLAG_END_DTMF_ONLY);
 
                return -1;
            }
 
            switch (f->frametype) {
            case AST_FRAME_DTMF_BEGIN:
                break;
            case AST_FRAME_DTMF_END:
                res = f->subclass.integer;
                if (!breakon || strchr(breakon, res)) {
                    ast_frfree(f);
                    ast_channel_clear_flag(c, AST_FLAG_END_DTMF_ONLY);
                    return res;
                }
                break;
            case AST_FRAME_CONTROL:
                switch (f->subclass.integer) {
                case AST_CONTROL_HANGUP:
                    ast_frfree(f);
                    ast_channel_clear_flag(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_channel_clear_flag(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 AST_CONTROL_FLASH:
                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_channel_clear_flag(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_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", (ast_json_int_t)duration_ms);
    if (!blob) {
        return;
    }
 
    ast_channel_publish_blob(chan, ast_channel_dtmf_end_type(), blob);
}
 
static void send_flash_event(struct ast_channel *chan)
{
    ast_channel_publish_blob(chan, ast_channel_flash_type(), NULL);
}
 
static void send_wink_event(struct ast_channel *chan)
{
    ast_channel_publish_blob(chan, ast_channel_wink_type(), NULL);
}
 
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;
        int trigger_dtmf_emulating = should_trigger_dtmf_emulating(chan);
 
        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 acknowledge 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);
                }
 
                if (trigger_dtmf_emulating) {
                    /*
                     * Since we're breaking out of this switch block and not
                     * returning, we need to re-lock the channel.
                     */
                    ast_channel_lock(chan);
                    /* generate null frame to trigger dtmf emulating */
                    f = &ast_null_frame;
                    break;
                }
            } else if (trigger_dtmf_emulating) {
                /* generate null frame to trigger dtmf emulating */
                f = &ast_null_frame;
                break;
            } else {
                ast_timer_set_rate(ast_channel_timer(chan), 0);
                /* generate very last null frame to trigger dtmf emulating */
                f = &ast_null_frame;
                break;
            }
 
            /* 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) {
        /* if the AST_GENERATOR_FD is set, call the generator with args
         * set to -1 so it can do whatever it needs to.
         */
        void *tmp = ast_channel_generatordata(chan);
        ast_channel_generatordata_set(chan, NULL);     /* reset to let ast_write get through */
        ast_channel_generator(chan)->generate(chan, tmp, -1, -1);
        ast_channel_generatordata_set(chan, tmp);
        f = &ast_null_frame;
        ast_channel_fdno_set(chan, -1);
        goto done;
    } else if (ast_channel_fd_isset(chan, AST_JITTERBUFFER_FD) && ast_channel_fdno(chan) == AST_JITTERBUFFER_FD) {
        ast_clear_flag(ast_channel_flags(chan), AST_FLAG_EXCEPTION);
    }
 
    /* Read and ignore anything on the alertpipe, but read only
       one sizeof(blah) per frame that we send from it */
    if (ast_channel_internal_alert_read(chan) == AST_ALERT_READ_FATAL) {
        f = &ast_null_frame;
        goto done;
    }
 
    /* Check for pending read queue */
    if (!AST_LIST_EMPTY(ast_channel_readq(chan))) {
        int skipped_dtmf_frame = 0;
        int skip_dtmf = should_skip_dtmf(chan);
 
        AST_LIST_TRAVERSE_SAFE_BEGIN(ast_channel_readq(chan), f, frame_list) {
            /* We have to be picky about which frame we pull off of the readq because
             * there are cases where we want to leave DTMF frames on the queue until
             * some later time. */
 
            if ( (f->frametype == AST_FRAME_DTMF_BEGIN || f->frametype == AST_FRAME_DTMF_END) && skip_dtmf) {
                skipped_dtmf_frame = 1;
                continue;
            }
 
            AST_LIST_REMOVE_CURRENT(frame_list);
            break;
        }
        AST_LIST_TRAVERSE_SAFE_END;
 
        if (!f) {
            /* There were no acceptable frames on the readq. */
            f = &ast_null_frame;
            if (!skipped_dtmf_frame) {
                /*
                 * Do not trigger alert pipe if only buffered dtmf begin or end frames
                 * are left in the readq.
                 */
                ast_channel_alert_write(chan);
            } else {
                /*
                 * Safely disable continous timer events if only buffered dtmf begin or end
                 * frames are left in the readq.
                 */
                ast_timer_disable_continuous(ast_channel_timer(chan));
            }
        }
 
        /* Interpret hangup and end-of-Q frames to return NULL */
        /* XXX why not the same for frames from the channel ? */
        if (f->frametype == AST_FRAME_CONTROL) {
            switch (f->subclass.integer) {
            case AST_CONTROL_HANGUP:
                ast_channel_softhangup_internal_flag_add(chan, AST_SOFTHANGUP_DEV);
                cause = f->data.uint32;
                /* Fall through */
            case AST_CONTROL_END_OF_Q:
                ast_frfree(f);
                f = NULL;
                break;
            default:
                break;
            }
        } else if (f->frametype == AST_FRAME_VOICE || f->frametype == AST_FRAME_VIDEO) {
            if (ast_channel_tech(chan) && ast_channel_tech(chan)->read_stream) {
                stream = ast_stream_topology_get_stream(ast_channel_get_stream_topology(chan), f->stream_num);
                default_stream = ast_channel_get_default_stream(chan, ast_format_get_type(f->subclass.format));
            } else {
                /* Since this channel driver does not support multistream determine the default stream this frame
                 * originated from and update the frame to include it.
                 */
                stream = default_stream = ast_channel_get_default_stream(chan, ast_format_get_type(f->subclass.format));
                /* In order to allow media to be passed up the underlying media type has to have a format negotiated on
                 * the channel itself. In cases where this hasn't happened the channel driver is incorrectly passing up
                 * a frame for a format that has not been negotiated. If this occurs just drop the frame as we have no
                 * stream that it came from.
                 */
                if (!stream) {
                    ast_frfree(f);
                    f = &ast_null_frame;
                } else {
                    f->stream_num = ast_stream_get_position(stream);
                }
            }
        }
    } else {
        if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_EXCEPTION)) {
            if (ast_channel_tech(chan)->exception)
                f = ast_channel_tech(chan)->exception(chan);
            else {
                ast_log(LOG_WARNING, "Exception flag set on '%s', but no exception handler\n", ast_channel_name(chan));
                f = &ast_null_frame;
            }
            /* Clear the exception flag */
            ast_clear_flag(ast_channel_flags(chan), AST_FLAG_EXCEPTION);
        } else if (ast_channel_tech(chan) && ast_channel_tech(chan)->read_stream) {
            f = ast_channel_tech(chan)->read_stream(chan);
 
            /* This channel driver supports multistream so the stream_num on the frame is valid, the only
             * thing different is that we need to find the default stream so we know whether to invoke the
             * default stream logic or not (such as transcoding).
             */
            if (f && (f->frametype == AST_FRAME_VOICE || f->frametype == AST_FRAME_VIDEO)) {
                stream = ast_stream_topology_get_stream(ast_channel_get_stream_topology(chan), f->stream_num);
                default_stream = ast_channel_get_default_stream(chan, ast_format_get_type(f->subclass.format));
            }
        } else if (ast_channel_tech(chan) && ast_channel_tech(chan)->read) {
            f = ast_channel_tech(chan)->read(chan);
 
            /* Since this channel driver does not support multistream determine the default stream this frame
             * originated from and update the frame to include it.
             */
            if (f && (f->frametype == AST_FRAME_VOICE || f->frametype == AST_FRAME_VIDEO)) {
                stream = default_stream = ast_channel_get_default_stream(chan, ast_format_get_type(f->subclass.format));
                if (!stream) {
                    ast_frfree(f);
                    f = &ast_null_frame;
                } else {
                    f->stream_num = ast_stream_get_position(stream);
                }
            }
        }
        else
            ast_log(LOG_WARNING, "No read routine on channel %s\n", ast_channel_name(chan));
    }
 
    if (stream == default_stream) {
        /* Perform the framehook read event here. After the frame enters the framehook list
         * there is no telling what will happen, <insert mad scientist laugh here>!!! */
        f = ast_framehook_list_read_event(ast_channel_framehooks(chan), f);
    }
 
    /*
     * Reset the recorded file descriptor that triggered this read so that we can
     * easily detect when ast_read() is called without properly using ast_waitfor().
     */
    ast_channel_fdno_set(chan, -1);
 
    if (f) {
        struct ast_frame *readq_tail = AST_LIST_LAST(ast_channel_readq(chan));
        struct ast_control_read_action_payload *read_action_payload;
        struct ast_party_connected_line connected;
        int hooked = 0;
 
        /* if the channel driver returned more than one frame, stuff the excess
           into the readq for the next ast_read call
        */
        if (AST_LIST_NEXT(f, frame_list)) {
            ast_queue_frame(chan, AST_LIST_NEXT(f, frame_list));
            ast_frfree(AST_LIST_NEXT(f, frame_list));
            AST_LIST_NEXT(f, frame_list) = NULL;
        }
 
        if (dropnondefault && stream != default_stream) {
            /* If the frame originates from a non-default stream and the caller can not handle other streams
             * absorb the frame and replace it with a null one instead.
             */
            ast_frfree(f);
            f = &ast_null_frame;
        }
 
        switch (f->frametype) {
        case AST_FRAME_CONTROL:
            if (f->subclass.integer == AST_CONTROL_ANSWER) {
                if (prestate == AST_STATE_UP && ast_channel_is_bridged(chan)) {
                    ast_debug(1, "Dropping duplicate answer!\n");
                    ast_frfree(f);
                    f = &ast_null_frame;
                } else {
                    /*
                     * Mark when outgoing channel answered so we can know how
                     * long the channel has been up.
                     */
                    set_channel_answer_time(chan);
 
                    ast_setstate(chan, AST_STATE_UP);
                }
            } else if (f->subclass.integer == AST_CONTROL_READ_ACTION) {
                read_action_payload = f->data.ptr;
                switch (read_action_payload->action) {
                case AST_FRAME_READ_ACTION_CONNECTED_LINE_MACRO:
                    ast_party_connected_line_init(&connected);
                    ast_party_connected_line_copy(&connected, ast_channel_connected(chan));
                    if (ast_connected_line_parse_data(read_action_payload->payload,
                        read_action_payload->payload_size, &connected)) {
                        ast_party_connected_line_free(&connected);
                        break;
                    }
                    ast_channel_unlock(chan);
                    if (ast_channel_connected_line_sub(NULL, chan, &connected, 0) &&
                        ast_channel_connected_line_macro(NULL, chan, &connected, 1, 0)) {
                        ast_indicate_data(chan, AST_CONTROL_CONNECTED_LINE,
                            read_action_payload->payload,
                            read_action_payload->payload_size);
                    }
                    ast_party_connected_line_free(&connected);
                    ast_channel_lock(chan);
                    break;
                case AST_FRAME_READ_ACTION_SEND_TEXT:
                    ast_channel_unlock(chan);
                    ast_sendtext(chan, (const char *)read_action_payload->payload);
                    ast_channel_lock(chan);
                    break;
                case AST_FRAME_READ_ACTION_SEND_TEXT_DATA:
                    ast_channel_unlock(chan);
                    ast_sendtext_data(chan, (struct ast_msg_data *)read_action_payload->payload);
                    ast_channel_lock(chan);
                    break;
                }
                ast_frfree(f);
                f = &ast_null_frame;
            } else if (f->subclass.integer == AST_CONTROL_STREAM_TOPOLOGY_REQUEST_CHANGE && dropnondefault) {
                /* The caller of this function is incapable of handling streams so we don't accept the change request
                 * and stick to the streams currently on the channel.
                 */
                ast_channel_stream_topology_changed(chan, ast_channel_get_stream_topology(chan));
                ast_frfree(f);
                f = &ast_null_frame;
            } else if (f->subclass.integer == AST_CONTROL_STREAM_TOPOLOGY_CHANGED && dropnondefault) {
                /* The caller of this function is incapable of handling streams so we absorb the notification that the
                 * stream topology has changed.
                 */
                ast_frfree(f);
                f = &ast_null_frame;
            } else if (f->subclass.integer == AST_CONTROL_FLASH) {
                send_flash_event(chan);
            } else if (f->subclass.integer == AST_CONTROL_WINK) {
                send_wink_event(chan);
            }
            break;
        case AST_FRAME_DTMF_END:
            send_dtmf_end_event(chan, DTMF_RECEIVED, f->subclass.integer, f->len);
            ast_log(LOG_DTMF, "DTMF end '%c' received on %s, duration %ld ms\n", f->subclass.integer, ast_channel_name(chan), f->len);
            /* Queue it up if DTMF is deferred, or if DTMF emulation is forced. */
            if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_DEFER_DTMF) || ast_test_flag(ast_channel_flags(chan), AST_FLAG_EMULATE_DTMF)) {
                queue_dtmf_readq(chan, f);
                ast_frfree(f);
                f = &ast_null_frame;
            } else if (!ast_test_flag(ast_channel_flags(chan), AST_FLAG_IN_DTMF | AST_FLAG_END_DTMF_ONLY)) {
                if (!ast_tvzero(*ast_channel_dtmf_tv(chan)) &&
                    ast_tvdiff_ms(ast_tvnow(), *ast_channel_dtmf_tv(chan)) < AST_MIN_DTMF_GAP) {
                    /* If it hasn't been long enough, defer this digit */
                    queue_dtmf_readq(chan, f);
                    ast_frfree(f);
                    f = &ast_null_frame;
                } else {
                    /* There was no begin, turn this into a begin and send the end later */
                    struct timeval tv = ast_tvnow();
                    f->frametype = AST_FRAME_DTMF_BEGIN;
                    ast_set_flag(ast_channel_flags(chan), AST_FLAG_EMULATE_DTMF);
                    ast_channel_dtmf_digit_to_emulate_set(chan, f->subclass.integer);
                    ast_channel_dtmf_tv_set(chan, &tv);
                    if (f->len) {
                        if (f->len > option_dtmfminduration)
                            ast_channel_emulate_dtmf_duration_set(chan, f->len);
                        else
                            ast_channel_emulate_dtmf_duration_set(chan, option_dtmfminduration);
                    } else
                        ast_channel_emulate_dtmf_duration_set(chan, AST_DEFAULT_EMULATE_DTMF_DURATION);
                    ast_log(LOG_DTMF, "DTMF begin emulation of '%c' with duration %u queued on %s\n", f->subclass.integer, ast_channel_emulate_dtmf_duration(chan), ast_channel_name(chan));
 
                    /*
                     * Start generating 50 fps timer events (null frames) for dtmf emulating
                     * independently from any existing incoming voice frames.
                     * If channel generator is already activated in regular mode use these
                     * timer events to generate null frames.
                     */
                    if (!ast_channel_generator(chan)) {
                        ast_timer_set_rate(ast_channel_timer(chan), 50);
                    }
                }
                if (ast_channel_audiohooks(chan)) {
                    struct ast_frame *old_frame = f;
                    /*!
                     * \todo XXX It is possible to write a digit to the audiohook twice
                     * if the digit was originally read while the channel was in autoservice. */
                    f = ast_audiohook_write_list(chan, ast_channel_audiohooks(chan), AST_AUDIOHOOK_DIRECTION_READ, f);
                    if (old_frame != f)
                        ast_frfree(old_frame);
                }
            } else {
                struct timeval now = ast_tvnow();
                if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_IN_DTMF)) {
                    ast_log(LOG_DTMF, "DTMF end accepted with begin '%c' on %s\n", f->subclass.integer, ast_channel_name(chan));
                    ast_clear_flag(ast_channel_flags(chan), AST_FLAG_IN_DTMF);
                    if (!f->len)
                        f->len = ast_tvdiff_ms(now, *ast_channel_dtmf_tv(chan));
 
                    /* detect tones that were received on
                     * the wire with durations shorter than
                     * option_dtmfminduration and set f->len
                     * to the actual duration of the DTMF
                     * frames on the wire.  This will cause
                     * dtmf emulation to be triggered later
                     * on.
                     */
                    if (ast_tvdiff_ms(now, *ast_channel_dtmf_tv(chan)) < option_dtmfminduration) {
                        f->len = ast_tvdiff_ms(now, *ast_channel_dtmf_tv(chan));
                        ast_log(LOG_DTMF, "DTMF end '%c' detected to have actual duration %ld on the wire, emulation will be triggered on %s\n", f->subclass.integer, f->len, ast_channel_name(chan));
                    }
                } else if (!f->len) {
                    ast_log(LOG_DTMF, "DTMF end accepted without begin '%c' on %s\n", f->subclass.integer, ast_channel_name(chan));
                    f->len = option_dtmfminduration;
                }
                if (f->len < option_dtmfminduration && !ast_test_flag(ast_channel_flags(chan), AST_FLAG_END_DTMF_ONLY)) {
                    ast_log(LOG_DTMF, "DTMF end '%c' has duration %ld but want minimum %u, emulating on %s\n", f->subclass.integer, f->len, option_dtmfminduration, ast_channel_name(chan));
                    ast_set_flag(ast_channel_flags(chan), AST_FLAG_EMULATE_DTMF);
                    ast_channel_dtmf_digit_to_emulate_set(chan, f->subclass.integer);
                    ast_channel_emulate_dtmf_duration_set(chan, option_dtmfminduration - f->len);
                    ast_frfree(f);
                    f = &ast_null_frame;
 
                    /* Start generating 50 fps timer events (null frames) for dtmf emulating
                     * independently from any existing incoming voice frames.
                     * If channel generator is already activated in regular mode use these
                     * timer events to generate null frames.
                     */
                    if (!ast_channel_generator(chan)) {
                        ast_timer_set_rate(ast_channel_timer(chan), 50);
                    }
                } else {
                    ast_log(LOG_DTMF, "DTMF end passthrough '%c' on %s\n", f->subclass.integer, ast_channel_name(chan));
                    if (f->len < option_dtmfminduration) {
                        f->len = option_dtmfminduration;
                    }
                    ast_channel_dtmf_tv_set(chan, &now);
 
                    /* Start generating 50 fps timer events (null frames) for dtmf emulating
                     * independently from any existing incoming voice frames.
                     * If channel generator is already activated in regular mode use these
                     * timer events to generate null frames.
                     */
                    if (!ast_channel_generator(chan)) {
                        ast_timer_set_rate(ast_channel_timer(chan), 50);
                    }
                }
                if (ast_channel_audiohooks(chan)) {
                    struct ast_frame *old_frame = f;
                    f = ast_audiohook_write_list(chan, ast_channel_audiohooks(chan), AST_AUDIOHOOK_DIRECTION_READ, f);
                    if (old_frame != f)
                        ast_frfree(old_frame);
                }
            }
            break;
        case AST_FRAME_DTMF_BEGIN:
            send_dtmf_begin_event(chan, DTMF_RECEIVED, f->subclass.integer);
            ast_log(LOG_DTMF, "DTMF begin '%c' received on %s\n", f->subclass.integer, ast_channel_name(chan));
            if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_DEFER_DTMF | AST_FLAG_END_DTMF_ONLY | AST_FLAG_EMULATE_DTMF) ||
                (!ast_tvzero(*ast_channel_dtmf_tv(chan)) &&
                  ast_tvdiff_ms(ast_tvnow(), *ast_channel_dtmf_tv(chan)) < AST_MIN_DTMF_GAP) ) {
                ast_log(LOG_DTMF, "DTMF begin ignored '%c' on %s\n", f->subclass.integer, ast_channel_name(chan));
                ast_frfree(f);
                f = &ast_null_frame;
            } else {
                struct timeval now = ast_tvnow();
                ast_set_flag(ast_channel_flags(chan), AST_FLAG_IN_DTMF);
                ast_channel_dtmf_tv_set(chan, &now);
                ast_log(LOG_DTMF, "DTMF begin passthrough '%c' on %s\n", f->subclass.integer, ast_channel_name(chan));
            }
            break;
        case AST_FRAME_NULL:
            /* The EMULATE_DTMF flag must be cleared here as opposed to when the duration
             * is reached , because we want to make sure we pass at least one
             * voice frame through before starting the next digit, to ensure a gap
             * between DTMF digits. */
            if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_EMULATE_DTMF)) {
                struct timeval now = ast_tvnow();
                if (!ast_channel_emulate_dtmf_duration(chan)) {
                    ast_clear_flag(ast_channel_flags(chan), AST_FLAG_EMULATE_DTMF);
                    ast_channel_dtmf_digit_to_emulate_set(chan, 0);
                } else if (ast_tvdiff_ms(now, *ast_channel_dtmf_tv(chan)) >= ast_channel_emulate_dtmf_duration(chan)) {
                    ast_channel_emulate_dtmf_duration_set(chan, 0);
                    ast_frfree(f);
                    f = ast_channel_dtmff(chan);
                    f->frametype = AST_FRAME_DTMF_END;
                    f->subclass.integer = ast_channel_dtmf_digit_to_emulate(chan);
                    f->len = ast_tvdiff_ms(now, *ast_channel_dtmf_tv(chan));
                    ast_channel_dtmf_tv_set(chan, &now);
                    ast_clear_flag(ast_channel_flags(chan), AST_FLAG_EMULATE_DTMF);
                    ast_channel_dtmf_digit_to_emulate_set(chan, 0);
                    ast_log(LOG_DTMF, "DTMF end emulation of '%c' queued on %s\n", f->subclass.integer, ast_channel_name(chan));
                    if (ast_channel_audiohooks(chan)) {
                        struct ast_frame *old_frame = f;
                        f = ast_audiohook_write_list(chan, ast_channel_audiohooks(chan), AST_AUDIOHOOK_DIRECTION_READ, f);
                        if (old_frame != f) {
                            ast_frfree(old_frame);
                        }
                    }
 
                    /* Start generating 50 fps timer events (null frames) for dtmf emulating
                     * independently from any existing incoming voice frames.
                     * If channel generator is already activated in regular mode use these
                     * timer events to generate null frames.
                     */
                    if (!ast_channel_generator(chan)) {
                        ast_timer_set_rate(ast_channel_timer(chan), 50);
                    }
                }
            }
            break;
        case AST_FRAME_VOICE:
            /* If media was received from a non-default stream don't perform any actions, let it just go through */
            if (stream != default_stream) {
                break;
            }
 
            /* The EMULATE_DTMF flag must be cleared here as opposed to when the duration
             * is reached , because we want to make sure we pass at least one
             * voice frame through before starting the next digit, to ensure a gap
             * between DTMF digits. */
            if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_EMULATE_DTMF) && !ast_channel_emulate_dtmf_duration(chan)) {
                ast_clear_flag(ast_channel_flags(chan), AST_FLAG_EMULATE_DTMF);
                ast_channel_dtmf_digit_to_emulate_set(chan, 0);
            }
 
            if (dropaudio || ast_test_flag(ast_channel_flags(chan), AST_FLAG_IN_DTMF)) {
                if (dropaudio)
                    ast_read_generator_actions(chan, f);
                ast_frfree(f);
                f = &ast_null_frame;
            }
 
            if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_EMULATE_DTMF) && !ast_test_flag(ast_channel_flags(chan), AST_FLAG_IN_DTMF)) {
                struct timeval now = ast_tvnow();
                if (ast_tvdiff_ms(now, *ast_channel_dtmf_tv(chan)) >= ast_channel_emulate_dtmf_duration(chan)) {
                    ast_channel_emulate_dtmf_duration_set(chan, 0);
                    ast_frfree(f);
                    f = ast_channel_dtmff(chan);
                    f->frametype = AST_FRAME_DTMF_END;
                    f->subclass.integer = ast_channel_dtmf_digit_to_emulate(chan);
                    f->len = ast_tvdiff_ms(now, *ast_channel_dtmf_tv(chan));
                    ast_channel_dtmf_tv_set(chan, &now);
                    if (ast_channel_audiohooks(chan)) {
                        struct ast_frame *old_frame = f;
                        f = ast_audiohook_write_list(chan, ast_channel_audiohooks(chan), AST_AUDIOHOOK_DIRECTION_READ, f);
                        if (old_frame != f)
                            ast_frfree(old_frame);
                    }
                    ast_log(LOG_DTMF, "DTMF end emulation of '%c' queued on %s\n", f->subclass.integer, ast_channel_name(chan));
                } else {
                    /* Drop voice frames while we're still in the middle of the digit */
                    ast_frfree(f);
                    f = &ast_null_frame;
                }
                break;
            }
            if (f->frametype != AST_FRAME_VOICE) {
                break;
            }
            if (ast_format_cmp(f->subclass.format, ast_channel_rawreadformat(chan)) != AST_FORMAT_CMP_EQUAL
                && ast_format_cmp(f->subclass.format, ast_channel_readformat(chan)) != AST_FORMAT_CMP_EQUAL) {
                struct ast_format *core_format;
 
                /*
                 * Note: This frame may not be one of the current native
                 * formats.  We may have gotten it out of the read queue from
                 * a previous multi-frame translation, from a framehook
                 * injected frame, or the device we're talking to isn't
                 * respecting negotiated formats.  Regardless we will accept
                 * all frames.
                 *
                 * Update the read translation path to handle the new format
                 * that just came in.  If the core wants slinear we need to
                 * setup a new translation path because the core is usually
                 * doing something with the audio itself and may not handle
                 * any other format.  e.g., Softmix bridge, holding bridge
                 * announcer channel, recording, AMD...  Otherwise, we'll
                 * setup to pass the frame as is to the core.  In this case
                 * the core doesn't care.  The channel is likely in
                 * autoservice, safesleep, or the channel is in a bridge.
                 * Let the bridge technology deal with format compatibility
                 * between the channels in the bridge.
                 *
                 * Beware of the transcode_via_slin and genericplc options as
                 * they force any transcoding to go through slin on a bridge.
                 * Unfortunately transcode_via_slin is enabled by default and
                 * genericplc is enabled in the codecs.conf.sample file.
                 *
                 * XXX Only updating translation to slinear frames has some
                 * corner cases if slinear is one of the native formats and
                 * there are different sample rates involved.  We might wind
                 * up with conflicting translation paths between channels
                 * where the read translation path on this channel reduces
                 * the sample rate followed by a write translation path on
                 * the peer channel that increases the sample rate.
                 */
                core_format = ast_channel_readformat(chan);
                if (!ast_format_cache_is_slinear(core_format)) {
                    core_format = f->subclass.format;
                }
                if (ast_set_read_format_path(chan, f->subclass.format, core_format)) {
                    /* Drop frame.  We couldn't make it compatible with the core. */
                    ast_frfree(f);
                    f = &ast_null_frame;
                    break;
                }
            }
            /*
             * Send frame to audiohooks if present, if frametype is linear, to preserve
             * functional compatibility with previous behavior. If not linear, hold off
             * until transcoding is done where we are more likely to have a linear frame
             */
            if (ast_channel_audiohooks(chan) && ast_format_cache_is_slinear(f->subclass.format)) {
                /* Place hooked after declaration */
                struct ast_frame *old_frame = f;
                hooked = 1;
 
                f = ast_audiohook_write_list(chan, ast_channel_audiohooks(chan), AST_AUDIOHOOK_DIRECTION_READ, f);
                if (old_frame != f) {
                    ast_frfree(old_frame);
                }
            }
 
            if (ast_channel_monitor(chan) && ast_channel_monitor(chan)->read_stream) {
                /* XXX what does this do ? */
#ifndef MONITOR_CONSTANT_DELAY
                int jump = ast_channel_outsmpl(chan) - ast_channel_insmpl(chan) - 4 * f->samples;
                if (jump >= 0) {
                    jump = calc_monitor_jump((ast_channel_outsmpl(chan) - ast_channel_insmpl(chan)),
                        ast_format_get_sample_rate(f->subclass.format),
                        ast_format_get_sample_rate(ast_channel_monitor(chan)->read_stream->fmt->format));
                    if (ast_seekstream(ast_channel_monitor(chan)->read_stream, jump, SEEK_FORCECUR) == -1) {
                        ast_log(LOG_WARNING, "Failed to perform seek in monitoring read stream, synchronization between the files may be broken\n");
                    }
                    ast_channel_insmpl_set(chan, ast_channel_insmpl(chan) + (ast_channel_outsmpl(chan) - ast_channel_insmpl(chan)) + f->samples);
                } else {
                    ast_channel_insmpl_set(chan, ast_channel_insmpl(chan) + f->samples);
                }
#else
                int jump = calc_monitor_jump((ast_channel_outsmpl(chan) - ast_channel_insmpl(chan)),
                    ast_format_get_sample_rate(f->subclass.format),
                    ast_format_get_sample_rate(ast_channel_monitor(chan)->read_stream->fmt->format));
                if (jump - MONITOR_DELAY >= 0) {
                    if (ast_seekstream(ast_channel_monitor(chan)->read_stream, jump - f->samples, SEEK_FORCECUR) == -1) {
                        ast_log(LOG_WARNING, "Failed to perform seek in monitoring read stream, synchronization between the files may be broken\n");
                    }
                    ast_channel_insmpl(chan) += ast_channel_outsmpl(chan) - ast_channel_insmpl(chan);
                } else {
                    ast_channel_insmpl(chan) += f->samples;
                }
#endif
                if (ast_channel_monitor(chan)->state == AST_MONITOR_RUNNING) {
                    if (ast_writestream(ast_channel_monitor(chan)->read_stream, f) < 0)
                        ast_log(LOG_WARNING, "Failed to write data to channel monitor read stream\n");
                }
            }
 
            if (ast_channel_readtrans(chan)
                && ast_format_cmp(f->subclass.format, ast_channel_rawreadformat(chan)) == AST_FORMAT_CMP_EQUAL) {
                f = ast_translate(ast_channel_readtrans(chan), f, 1);
                if (!f) {
                    f = &ast_null_frame;
                }
            }
 
            /* Second chance at hooking a linear frame, also the last chance */
            if (ast_channel_audiohooks(chan) && !hooked) {
                struct ast_frame *old_frame = f;
 
                f = ast_audiohook_write_list(chan, ast_channel_audiohooks(chan), AST_AUDIOHOOK_DIRECTION_READ, f);
                if (old_frame != f) {
                    ast_frfree(old_frame);
                }
            }
 
            /*
             * It is possible for the translation process on the channel to have
             * produced multiple frames from the single input frame we passed it; if
             * this happens, queue the additional frames *before* the frames we may
             * have queued earlier. if the readq was empty, put them at the head of
             * the queue, and if it was not, put them just after the frame that was
             * at the end of the queue.
             */
            if (AST_LIST_NEXT(f, frame_list)) {
                struct ast_frame *cur, *multi_frame = AST_LIST_NEXT(f, frame_list);
 
                /* Mark these frames as being re-queued */
                for (cur = multi_frame; cur; cur = AST_LIST_NEXT(cur, frame_list)) {
                    ast_set_flag(cur, AST_FRFLAG_REQUEUED);
                }
 
                if (!readq_tail) {
                    ast_queue_frame_head(chan, multi_frame);
                } else {
                    __ast_queue_frame(chan, multi_frame, 0, readq_tail);
                }
                ast_frfree(multi_frame);
                AST_LIST_NEXT(f, frame_list) = NULL;
            }
 
            /*
             * Run generator sitting on the line if timing device not available
             * and synchronous generation of outgoing frames is necessary
             */
            ast_read_generator_actions(chan, f);
            break;
        case AST_FRAME_RTCP:
            /* Incoming RTCP feedback needs to get to the translator for
             * outgoing media, which means we treat it as an ast_write */
            if (ast_channel_writetrans(chan)) {
                ast_translate(ast_channel_writetrans(chan), f, 0);
            }
            break;
        default:
            /* Just pass it on! */
            break;
        }
    } else {
        /* Make sure we always return NULL in the future */
        if (!ast_channel_softhangup_internal_flag(chan)) {
            ast_channel_softhangup_internal_flag_add(chan, AST_SOFTHANGUP_DEV);
        }
        if (cause)
            ast_channel_hangupcause_set(chan, cause);
        if (ast_channel_generator(chan))
            ast_deactivate_generator(chan);
        /* We no longer End the CDR here */
    }
 
    /* High bit prints debugging */
    if (ast_channel_fin(chan) & DEBUGCHAN_FLAG)
        ast_frame_dump(ast_channel_name(chan), f, "<<");
    ast_channel_fin_set(chan, FRAMECOUNT_INC(ast_channel_fin(chan)));
 
done:
    if (ast_channel_music_state(chan) && ast_channel_generator(chan) && ast_channel_generator(chan)->digit && f && f->frametype == AST_FRAME_DTMF_END)
        ast_channel_generator(chan)->digit(chan, f->subclass.integer);
 
    if (ast_channel_audiohooks(chan) && ast_audiohook_write_list_empty(ast_channel_audiohooks(chan))) {
        /* The list gets recreated if audiohooks are added again later */
        ast_audiohook_detach_list(ast_channel_audiohooks(chan));
        ast_channel_audiohooks_set(chan, NULL);
    }
    ast_channel_unlock(chan);
    return f;
}
 
struct ast_frame *ast_read(struct ast_channel *chan)
{
    return __ast_read(chan, 0, 1);
}
 
struct ast_frame *ast_read_stream(struct ast_channel *chan)
{
    return __ast_read(chan, 0, 0);
}
 
struct ast_frame *ast_read_noaudio(struct ast_channel *chan)
{
    return __ast_read(chan, 1, 1);
}
 
struct ast_frame *ast_read_stream_noaudio(struct ast_channel *chan)
{
    return __ast_read(chan, 1, 0);
}
 
int ast_indicate(struct ast_channel *chan, int condition)
{
    return ast_indicate_data(chan, condition, NULL, 0);
}
 
static int attribute_const is_visible_indication(enum ast_control_frame_type condition)
{
    /* Don't include a default case here so that we get compiler warnings
     * when a new type is added. */
 
    switch (condition) {
    case AST_CONTROL_PROGRESS:
    case AST_CONTROL_PROCEEDING:
    case AST_CONTROL_VIDUPDATE:
    case AST_CONTROL_SRCUPDATE:
    case AST_CONTROL_SRCCHANGE:
    case AST_CONTROL_RADIO_KEY:
    case AST_CONTROL_RADIO_UNKEY:
    case AST_CONTROL_OPTION:
    case AST_CONTROL_WINK:
    case AST_CONTROL_FLASH:
    case AST_CONTROL_OFFHOOK:
    case AST_CONTROL_TAKEOFFHOOK:
    case AST_CONTROL_ANSWER:
    case AST_CONTROL_HANGUP:
    case AST_CONTROL_CONNECTED_LINE:
    case AST_CONTROL_REDIRECTING:
    case AST_CONTROL_TRANSFER:
    case AST_CONTROL_T38_PARAMETERS:
    case _XXX_AST_CONTROL_T38:
    case AST_CONTROL_CC:
    case AST_CONTROL_READ_ACTION:
    case AST_CONTROL_AOC:
    case AST_CONTROL_END_OF_Q:
    case AST_CONTROL_MCID:
    case AST_CONTROL_UPDATE_RTP_PEER:
    case AST_CONTROL_PVT_CAUSE_CODE:
    case AST_CONTROL_MASQUERADE_NOTIFY:
    case AST_CONTROL_STREAM_TOPOLOGY_REQUEST_CHANGE:
    case AST_CONTROL_STREAM_TOPOLOGY_CHANGED:
    case AST_CONTROL_STREAM_TOPOLOGY_SOURCE_CHANGED:
    case AST_CONTROL_STREAM_STOP:
    case AST_CONTROL_STREAM_SUSPEND:
    case AST_CONTROL_STREAM_REVERSE:
    case AST_CONTROL_STREAM_FORWARD:
    case AST_CONTROL_STREAM_RESTART:
    case AST_CONTROL_RECORD_CANCEL:
    case AST_CONTROL_RECORD_STOP:
    case AST_CONTROL_RECORD_SUSPEND:
    case AST_CONTROL_RECORD_MUTE:
        break;
 
    case AST_CONTROL_INCOMPLETE:
    case AST_CONTROL_CONGESTION:
    case AST_CONTROL_BUSY:
    case AST_CONTROL_RINGING:
    case AST_CONTROL_RING:
    case AST_CONTROL_HOLD:
        /* You can hear these */
        return 1;
 
    case AST_CONTROL_UNHOLD:
        /* This is a special case.  You stop hearing this. */
        break;
    }
 
    return 0;
}
 
void ast_channel_hangupcause_hash_set(struct ast_channel *chan, const struct ast_control_pvt_cause_code *cause_code, int datalen)
{
    char causevar[256];
 
    if (ast_channel_dialed_causes_add(chan, cause_code, datalen)) {
        ast_log(LOG_WARNING, "Unable to store hangup cause for %s on %s\n", cause_code->chan_name, ast_channel_name(chan));
    }
 
    if (cause_code->emulate_sip_cause) {
        snprintf(causevar, sizeof(causevar), "HASH(SIP_CAUSE,%s)", cause_code->chan_name);
        ast_func_write(chan, causevar, cause_code->code);
    }
}
 
enum ama_flags ast_channel_string2amaflag(const char *flag)
{
    if (!strcasecmp(flag, "default"))
        return DEFAULT_AMA_FLAGS;
    if (!strcasecmp(flag, "omit"))
        return AST_AMA_OMIT;
    if (!strcasecmp(flag, "billing"))
        return AST_AMA_BILLING;
    if (!strcasecmp(flag, "documentation"))
        return AST_AMA_DOCUMENTATION;
    return AST_AMA_NONE;
}
 
const char *ast_channel_amaflags2string(enum ama_flags flag)
{
    switch (flag) {
    case AST_AMA_OMIT:
        return "OMIT";
    case AST_AMA_BILLING:
        return "BILLING";
    case AST_AMA_DOCUMENTATION:
        return "DOCUMENTATION";
    default:
        return "Unknown";
    }
}
 
/*!
 * \internal
 * \brief Preprocess connected line update.
 * \since 12.0.0
 *
 * \param chan channel to change the indication
 * \param data pointer to payload data
 * \param datalen size of payload data
 *
 * \note This function assumes chan is locked.
 *
 * \retval 0 keep going.
 * \retval -1 quit now.
 */
static int indicate_connected_line(struct ast_channel *chan, const void *data, size_t datalen)
{
    struct ast_party_connected_line *chan_connected = ast_channel_connected(chan);
    struct ast_party_connected_line *chan_indicated = ast_channel_connected_indicated(chan);
    struct ast_party_connected_line connected;
    unsigned char current[1024];
    unsigned char proposed[1024];
    int current_size;
    int proposed_size;
    int res;
 
    ast_party_connected_line_set_init(&connected, chan_connected);
    res = ast_connected_line_parse_data(data, datalen, &connected);
    if (!res) {
        ast_channel_set_connected_line(chan, &connected, NULL);
    }
    ast_party_connected_line_free(&connected);
    if (res) {
        return -1;
    }
 
    current_size = ast_connected_line_build_data(current, sizeof(current),
        chan_indicated, NULL);
    proposed_size = ast_connected_line_build_data(proposed, sizeof(proposed),
        chan_connected, NULL);
    if (current_size == -1 || proposed_size == -1) {
        return -1;
    }
 
    if (current_size == proposed_size && !memcmp(current, proposed, current_size)) {
        ast_debug(1, "%s: Dropping redundant connected line update \"%s\" <%s>.\n",
            ast_channel_name(chan),
            S_COR(chan_connected->id.name.valid, chan_connected->id.name.str, ""),
            S_COR(chan_connected->id.number.valid, chan_connected->id.number.str, ""));
        return -1;
    }
 
    ast_party_connected_line_copy(chan_indicated, chan_connected);
    return 0;
}
 
/*!
 * \internal
 * \brief Preprocess redirecting update.
 * \since 12.0.0
 *
 * \param chan channel to change the indication
 * \param data pointer to payload data
 * \param datalen size of payload data
 *
 * \note This function assumes chan is locked.
 *
 * \retval 0 keep going.
 * \retval -1 quit now.
 */
static int indicate_redirecting(struct ast_channel *chan, const void *data, size_t datalen)
{
    struct ast_party_redirecting redirecting;
    int res;
 
    ast_party_redirecting_set_init(&redirecting, ast_channel_redirecting(chan));
    res = ast_redirecting_parse_data(data, datalen, &redirecting);
    if (!res) {
        ast_channel_set_redirecting(chan, &redirecting, NULL);
    }
    ast_party_redirecting_free(&redirecting);
    return res ? -1 : 0;
}
 
static int indicate_data_internal(struct ast_channel *chan, int _condition, const void *data, size_t datalen)
{
    /* By using an enum, we'll get compiler warnings for values not handled
     * in switch statements. */
    enum ast_control_frame_type condition = _condition;
    struct ast_tone_zone_sound *ts = NULL;
    const struct ast_control_t38_parameters *t38_parameters;
    int res;
 
    switch (condition) {
    case AST_CONTROL_CONNECTED_LINE:
        if (indicate_connected_line(chan, data, datalen)) {
            res = 0;
            return res;
        }
        break;
    case AST_CONTROL_REDIRECTING:
        if (indicate_redirecting(chan, data, datalen)) {
            res = 0;
            return res;
        }
        break;
    case AST_CONTROL_HOLD:
    case AST_CONTROL_UNHOLD:
        ast_channel_hold_state_set(chan, _condition);
        break;
    case AST_CONTROL_T38_PARAMETERS:
        t38_parameters = data;
        switch (t38_parameters->request_response) {
        case AST_T38_REQUEST_NEGOTIATE:
        case AST_T38_NEGOTIATED:
            ast_channel_set_is_t38_active_nolock(chan, 1);
            break;
        case AST_T38_REQUEST_TERMINATE:
        case AST_T38_TERMINATED:
        case AST_T38_REFUSED:
            ast_channel_set_is_t38_active_nolock(chan, 0);
            break;
        default:
            break;
        }
        break;
    default:
        break;
    }
 
    if (is_visible_indication(condition)) {
        /* A new visible indication is requested. */
        ast_channel_visible_indication_set(chan, _condition);
    } else if (condition == AST_CONTROL_UNHOLD || _condition < 0) {
        /* Visible indication is cleared/stopped. */
        ast_channel_visible_indication_set(chan, 0);
    }
 
    if (ast_channel_tech(chan)->indicate) {
        /* See if the channel driver can handle this condition. */
        res = ast_channel_tech(chan)->indicate(chan, _condition, data, datalen);
    } else {
        res = -1;
    }
 
    if (!res) {
        /* The channel driver successfully handled this indication */
        res = 0;
        return res;
    }
 
    /* The channel driver does not support this indication, let's fake
     * it by doing our own tone generation if applicable. */
 
    /*!\note If we compare the enumeration type, which does not have any
     * negative constants, the compiler may optimize this code away.
     * Therefore, we must perform an integer comparison here. */
    if (_condition < 0) {
        /* Stop any tones that are playing */
        ast_playtones_stop(chan);
        res = 0;
        return res;
    }
 
    /* Handle conditions that we have tones for. */
    switch (condition) {
    case _XXX_AST_CONTROL_T38:
        /* deprecated T.38 control frame */
        res = -1;
        return res;
    case AST_CONTROL_T38_PARAMETERS:
        /* there is no way to provide 'default' behavior for these
         * control frames, so we need to return failure, but there
         * is also no value in the log message below being emitted
         * since failure to handle these frames is not an 'error'
         * so just return right now. in addition, we want to return
         * whatever value the channel driver returned, in case it
         * has some meaning.*/
        return res;
    case AST_CONTROL_RINGING:
        ts = ast_get_indication_tone(ast_channel_zone(chan), "ring");
        /* It is common practice for channel drivers to return -1 if trying
         * to indicate ringing on a channel which is up. The idea is to let the
         * core generate the ringing inband. However, we don't want the
         * warning message about not being able to handle the specific indication
         * to print nor do we want ast_indicate_data to return an "error" for this
         * condition
         */
        if (ast_channel_state(chan) == AST_STATE_UP) {
            res = 0;
        }
        break;
    case AST_CONTROL_BUSY:
        ts = ast_get_indication_tone(ast_channel_zone(chan), "busy");
        break;
    case AST_CONTROL_INCOMPLETE:
    case AST_CONTROL_CONGESTION:
        ts = ast_get_indication_tone(ast_channel_zone(chan), "congestion");
        break;
    case AST_CONTROL_PVT_CAUSE_CODE:
        ast_channel_hangupcause_hash_set(chan, data, datalen);
        res = 0;
        break;
    case AST_CONTROL_PROGRESS:
    case AST_CONTROL_PROCEEDING:
    case AST_CONTROL_VIDUPDATE:
    case AST_CONTROL_SRCUPDATE:
    case AST_CONTROL_SRCCHANGE:
    case AST_CONTROL_RADIO_KEY:
    case AST_CONTROL_RADIO_UNKEY:<