channel_internal_api.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2012, Digium, Inc.
 *
 * Mark Spencer <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Channel Accessor API
 *
 * This file is intended to be the only file that ever accesses the
 * internals of an ast_channel. All other files should use the
 * accessor functions defined here.
 *
 * \author Terry Wilson
 */

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

#include "asterisk.h"

#include <unistd.h>
#include <fcntl.h>

#include "asterisk/alertpipe.h"
#include "asterisk/paths.h"
#include "asterisk/channel.h"
#include "asterisk/channel_internal.h"
#include "asterisk/endpoints.h"
#include "asterisk/indications.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/stasis_endpoints.h"
#include "asterisk/stringfields.h"
#include "asterisk/stream.h"
#include "asterisk/test.h"
#include "asterisk/vector.h"

/*!
 * \brief Channel UniqueId structure
 * \note channel creation time used for determining LinkedId Propagation
 */
struct ast_channel_id {
   time_t creation_time;            /*!< Creation time */
   int creation_unique;          /*!< sub-second unique value */
   char unique_id[AST_MAX_UNIQUEID];   /*!< Unique Identifier */
};

/*!
 * \brief Main Channel structure associated with a channel.
 *
 * \note When adding fields to this structure, it is important to add the field
 *       'in position' with like-aligned fields, so as to keep the compiler from
 *       having to add padding to align fields. The structure's fields are sorted
 *       in this order: pointers, structures, long, int/enum, short, char. This
 *       is especially important on 64-bit architectures, where mixing 4-byte
 *       and 8-byte fields causes 4 bytes of padding to be added before many
 *       8-byte fields.
 */
struct ast_channel {
   const struct ast_channel_tech *tech;      /*!< Technology (point to channel driver) */
   void *tech_pvt;               /*!< Private data used by the technology driver */
   void *music_state;            /*!< Music State*/
   void *generatordata;          /*!< Current generator data if there is any */
   struct ast_generator *generator;    /*!< Current active data generator */
   struct ast_channel *masq;        /*!< Channel that will masquerade as us */
   struct ast_channel *masqr;       /*!< Who we are masquerading as */
   const char *blockproc;           /*!< Procedure causing blocking */
   const char *appl;          /*!< Current application */
   const char *data;          /*!< Data passed to current application */
   struct ast_sched_context *sched;                /*!< Schedule context */
   struct ast_filestream *stream;         /*!< Stream itself. */
   struct ast_filestream *vstream;        /*!< Video Stream itself. */
   ast_timing_func_t timingfunc;
   void *timingdata;
   struct ast_pbx *pbx;          /*!< PBX private structure for this channel */
   struct ast_trans_pvt *writetrans;      /*!< Write translation path */
   struct ast_trans_pvt *readtrans;    /*!< Read translation path */
   struct ast_audiohook_list *audiohooks;
   struct ast_framehook_list *framehooks;
   struct ast_cdr *cdr;          /*!< Call Detail Record */
   struct ast_tone_zone *zone;         /*!< Tone zone as set in indications.conf or
                      *   in the CHANNEL dialplan function */
   struct ast_channel_monitor *monitor;      /*!< Channel monitoring */
   ast_callid callid;         /*!< Bound call identifier pointer */
   struct ao2_container *dialed_causes;      /*!< Contains tech-specific and Asterisk cause data from dialed channels */

   AST_DECLARE_STRING_FIELDS(
      AST_STRING_FIELD(name);         /*!< ASCII unique channel name */
      AST_STRING_FIELD(language);     /*!< Language requested for voice prompts */
      AST_STRING_FIELD(musicclass);   /*!< Default music class */
      AST_STRING_FIELD(latest_musicclass);   /*!< Latest active music class */
      AST_STRING_FIELD(accountcode);  /*!< Account code for billing */
      AST_STRING_FIELD(peeraccount);  /*!< Peer account code for billing */
      AST_STRING_FIELD(userfield);    /*!< Userfield for CEL billing */
      AST_STRING_FIELD(call_forward); /*!< Where to forward to if asked to dial on this interface */
      AST_STRING_FIELD(parkinglot);   /*! Default parking lot, if empty, default parking lot  */
      AST_STRING_FIELD(hangupsource); /*! Who is responsible for hanging up this channel */
      AST_STRING_FIELD(dialcontext);  /*!< Dial: Extension context that we were called from */
   );

   struct ast_channel_id uniqueid;     /*!< Unique Channel Identifier - can be specified on creation */
   struct ast_channel_id linkedid;     /*!< Linked Channel Identifier - oldest propagated when bridged */

   struct timeval whentohangup; /*!< Non-zero, set to actual time when channel is to be hung up */
   pthread_t blocker;           /*!< If anyone is blocking, this is them */

   /*!
    * \brief Dialed/Called information.
    * \note Set on incoming channels to indicate the originally dialed party.
    * \note Dialed Number Identifier (DNID)
    */
   struct ast_party_dialed dialed;

   /*!
    * \brief Channel Caller ID information.
    * \note The caller id information is the caller id of this
    * channel when it is used to initiate a call.
    */
   struct ast_party_caller caller;

   /*!
    * \brief Channel Connected Line ID information.
    * \note The connected line information identifies the channel
    * connected/bridged to this channel.
    */
   struct ast_party_connected_line connected;

   /*!
    * \brief Channel Connected Line ID information that was last indicated.
    */
   struct ast_party_connected_line connected_indicated;

   /*! \brief Redirecting/Diversion information */
   struct ast_party_redirecting redirecting;

   struct ast_frame dtmff;          /*!< DTMF frame */
   struct varshead varshead;        /*!< A linked list for channel variables. See \ref AstChanVar */
   ast_group_t callgroup;           /*!< Call group for call pickups */
   ast_group_t pickupgroup;         /*!< Pickup group - which calls groups can be picked up? */
   struct ast_namedgroups *named_callgroups; /*!< Named call group for call pickups */
   struct ast_namedgroups *named_pickupgroups;  /*!< Named pickup group - which call groups can be picked up? */
   struct timeval creationtime;        /*!< The time of channel creation */
   struct timeval answertime;          /*!< The time the channel was answered */
   struct ast_readq_list readq;
   struct ast_jb jb;          /*!< The jitterbuffer state */
   struct timeval dtmf_tv;          /*!< The time that an in process digit began, or the last digit ended */
   struct ast_hangup_handler_list hangup_handlers;/*!< Hangup handlers on the channel. */
   struct ast_datastore_list datastores; /*!< Data stores on the channel */
   struct ast_autochan_list autochans; /*!< Autochans on the channel */
   unsigned long insmpl;            /*!< Track the read/written samples for monitor use */
   unsigned long outsmpl;           /*!< Track the read/written samples for monitor use */

   int blocker_tid;              /*!< If anyone is blocking, this is their thread id */
   AST_VECTOR(, int) fds;           /*!< File descriptors for channel -- Drivers will poll on
                      *   these file descriptors, so at least one must be non -1.
                      *   See \arg \ref AstFileDesc */
   int softhangup;            /*!< Whether or not we have been hung up...  Do not set this value
                      *   directly, use ast_softhangup() */
   int fdno;               /*!< Which fd had an event detected on */
   int streamid;              /*!< For streaming playback, the schedule ID */
   int vstreamid;             /*!< For streaming video playback, the schedule ID */
   struct ast_format *oldwriteformat;  /*!< Original writer format */
   int timingfd;              /*!< Timing fd */
   enum ast_channel_state state;       /*!< State of line -- Don't write directly, use ast_setstate() */
   int rings;              /*!< Number of rings so far */
   int priority;              /*!< Dialplan: Current extension priority */
   int macropriority;            /*!< Macro: Current non-macro priority. See app_macro.c */
   int amaflags;              /*!< Set BEFORE PBX is started to determine AMA flags */
   enum ast_channel_adsicpe adsicpe;      /*!< Whether or not ADSI is detected on CPE */
   unsigned int fin;          /*!< Frames in counters. The high bit is a debug mask, so
                      *   the counter is only in the remaining bits */
   unsigned int fout;            /*!< Frames out counters. The high bit is a debug mask, so
                      *   the counter is only in the remaining bits */
   int hangupcause;           /*!< Why is the channel hanged up. See causes.h */
   unsigned int finalized:1;       /*!< Whether or not the channel has been successfully allocated */
   struct ast_flags flags;          /*!< channel flags of AST_FLAG_ type */
   int alertpipe[2];
   struct ast_format_cap *nativeformats;         /*!< Kinds of data this channel can natively handle */
   struct ast_format *readformat;            /*!< Requested read format (after translation) */
   struct ast_format *writeformat;           /*!< Requested write format (before translation) */
   struct ast_format *rawreadformat;         /*!< Raw read format (before translation) */
   struct ast_format *rawwriteformat;        /*!< Raw write format (after translation) */
   unsigned int emulate_dtmf_duration;    /*!< Number of ms left to emulate DTMF for */
   int visible_indication;                         /*!< Indication currently playing on the channel */
   int hold_state;                     /*!< Current Hold/Unhold state */

   unsigned short transfercapability;     /*!< ISDN Transfer Capability - AST_FLAG_DIGITAL is not enough */

   struct ast_bridge *bridge;                      /*!< Bridge this channel is participating in */
   struct ast_bridge_channel *bridge_channel;/*!< The bridge_channel this channel is linked with. */
   struct ast_timer *timer;         /*!< timer object that provided timingfd */

   char context[AST_MAX_CONTEXT];         /*!< Dialplan: Current extension context */
   char exten[AST_MAX_EXTENSION];         /*!< Dialplan: Current extension number */
   char macrocontext[AST_MAX_CONTEXT];    /*!< Macro: Current non-macro context. See app_macro.c */
   char macroexten[AST_MAX_EXTENSION];    /*!< Macro: Current non-macro extension. See app_macro.c */
   char unbridged;                     /*!< non-zero if the bridge core needs to re-evaluate the current
                                  bridging technology which is in use by this channel's bridge. */
   char is_t38_active;                 /*!< non-zero if T.38 is active on this channel. */
   char dtmf_digit_to_emulate;         /*!< Digit being emulated */
   char sending_dtmf_digit;         /*!< Digit this channel is currently sending out. (zero if not sending) */
   struct timeval sending_dtmf_tv;     /*!< The time this channel started sending the current digit. (Invalid if sending_dtmf_digit is zero.) */
   struct stasis_topic *topic;      /*!< Topic for trhis channel */
   struct stasis_forward *channel_forward; /*!< Subscription for event forwarding to all channel topic */
   struct stasis_forward *endpoint_forward;  /*!< Subscription for event forwarding to endpoint's topic */
   struct ast_stream_topology *stream_topology; /*!< Stream topology */
   void *stream_topology_change_source; /*!< Source that initiated a stream topology change */
   struct ast_stream *default_streams[AST_MEDIA_TYPE_END]; /*!< Default streams indexed by media type */
   struct ast_channel_snapshot *snapshot; /*!< The current up to date snapshot of the channel */
   struct ast_flags snapshot_segment_flags; /*!< Flags regarding the segments of the snapshot */
};

/*! \brief The monotonically increasing integer counter for channel uniqueids */
static int uniqueint;

/* ACCESSORS */

#define DEFINE_STRINGFIELD_SETTERS_FOR(field, assert_on_null) \
void ast_channel_##field##_set(struct ast_channel *chan, const char *value) \
{ \
   if ((assert_on_null)) ast_assert(!ast_strlen_zero(value)); \
   if (!strcmp(value, chan->field)) return; \
   ast_string_field_set(chan, field, value); \
} \
  \
void ast_channel_##field##_build_va(struct ast_channel *chan, const char *fmt, va_list ap) \
{ \
   ast_string_field_build_va(chan, field, fmt, ap); \
} \
void ast_channel_##field##_build(struct ast_channel *chan, const char *fmt, ...) \
{ \
   va_list ap; \
   va_start(ap, fmt); \
   ast_channel_##field##_build_va(chan, fmt, ap); \
   va_end(ap); \
}

#define DEFINE_STRINGFIELD_SETTERS_AND_INVALIDATE_FOR(field, publish, assert_on_null, invalidate) \
void ast_channel_##field##_set(struct ast_channel *chan, const char *value) \
{ \
   if ((assert_on_null)) ast_assert(!ast_strlen_zero(value)); \
   if (!strcmp(value, chan->field)) return; \
   ast_string_field_set(chan, field, value); \
   ast_channel_snapshot_invalidate_segment(chan, invalidate); \
   if (publish && ast_channel_internal_is_finalized(chan)) ast_channel_publish_snapshot(chan); \
} \
  \
void ast_channel_##field##_build_va(struct ast_channel *chan, const char *fmt, va_list ap) \
{ \
   ast_string_field_build_va(chan, field, fmt, ap); \
   ast_channel_snapshot_invalidate_segment(chan, invalidate); \
   if (publish && ast_channel_internal_is_finalized(chan)) ast_channel_publish_snapshot(chan); \
} \
void ast_channel_##field##_build(struct ast_channel *chan, const char *fmt, ...) \
{ \
   va_list ap; \
   va_start(ap, fmt); \
   ast_channel_##field##_build_va(chan, fmt, ap); \
   va_end(ap); \
}

DEFINE_STRINGFIELD_SETTERS_AND_INVALIDATE_FOR(name, 0, 1, AST_CHANNEL_SNAPSHOT_INVALIDATE_BASE);
DEFINE_STRINGFIELD_SETTERS_AND_INVALIDATE_FOR(language, 1, 0, AST_CHANNEL_SNAPSHOT_INVALIDATE_BASE);
DEFINE_STRINGFIELD_SETTERS_FOR(musicclass, 0);
DEFINE_STRINGFIELD_SETTERS_FOR(latest_musicclass, 0);
DEFINE_STRINGFIELD_SETTERS_AND_INVALIDATE_FOR(accountcode, 1, 0, AST_CHANNEL_SNAPSHOT_INVALIDATE_BASE);
DEFINE_STRINGFIELD_SETTERS_AND_INVALIDATE_FOR(peeraccount, 1, 0, AST_CHANNEL_SNAPSHOT_INVALIDATE_PEER);
DEFINE_STRINGFIELD_SETTERS_AND_INVALIDATE_FOR(userfield, 0, 0, AST_CHANNEL_SNAPSHOT_INVALIDATE_BASE);
DEFINE_STRINGFIELD_SETTERS_FOR(call_forward, 0);
DEFINE_STRINGFIELD_SETTERS_FOR(parkinglot, 0);
DEFINE_STRINGFIELD_SETTERS_AND_INVALIDATE_FOR(hangupsource, 0, 0, AST_CHANNEL_SNAPSHOT_INVALIDATE_HANGUP);
DEFINE_STRINGFIELD_SETTERS_FOR(dialcontext, 0);

#define DEFINE_STRINGFIELD_GETTER_FOR(field) const char *ast_channel_##field(const struct ast_channel *chan) \
{ \
   return chan->field; \
}

DEFINE_STRINGFIELD_GETTER_FOR(name);
DEFINE_STRINGFIELD_GETTER_FOR(language);
DEFINE_STRINGFIELD_GETTER_FOR(musicclass);
DEFINE_STRINGFIELD_GETTER_FOR(latest_musicclass);
DEFINE_STRINGFIELD_GETTER_FOR(accountcode);
DEFINE_STRINGFIELD_GETTER_FOR(peeraccount);
DEFINE_STRINGFIELD_GETTER_FOR(userfield);
DEFINE_STRINGFIELD_GETTER_FOR(call_forward);
DEFINE_STRINGFIELD_GETTER_FOR(parkinglot);
DEFINE_STRINGFIELD_GETTER_FOR(hangupsource);
DEFINE_STRINGFIELD_GETTER_FOR(dialcontext);

const char *ast_channel_uniqueid(const struct ast_channel *chan)
{
   ast_assert(chan->uniqueid.unique_id[0] != '\0');
   return chan->uniqueid.unique_id;
}

const char *ast_channel_linkedid(const struct ast_channel *chan)
{
   ast_assert(chan->linkedid.unique_id[0] != '\0');
   return chan->linkedid.unique_id;
}

const char *ast_channel_appl(const struct ast_channel *chan)
{
   return chan->appl;
}
void ast_channel_appl_set(struct ast_channel *chan, const char *value)
{
   chan->appl = value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_DIALPLAN);
}
const char *ast_channel_blockproc(const struct ast_channel *chan)
{
   return chan->blockproc;
}
void ast_channel_blockproc_set(struct ast_channel *chan, const char *value)
{
   chan->blockproc = value;
}
const char *ast_channel_data(const struct ast_channel *chan)
{
   return chan->data;
}
void ast_channel_data_set(struct ast_channel *chan, const char *value)
{
   chan->data = value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_DIALPLAN);
}

const char *ast_channel_context(const struct ast_channel *chan)
{
   return chan->context;
}
void ast_channel_context_set(struct ast_channel *chan, const char *value)
{
   ast_copy_string(chan->context, value, sizeof(chan->context));
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_DIALPLAN);
}
const char *ast_channel_exten(const struct ast_channel *chan)
{
   return chan->exten;
}
void ast_channel_exten_set(struct ast_channel *chan, const char *value)
{
   ast_copy_string(chan->exten, value, sizeof(chan->exten));
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_DIALPLAN);
}
const char *ast_channel_macrocontext(const struct ast_channel *chan)
{
   return chan->macrocontext;
}
void ast_channel_macrocontext_set(struct ast_channel *chan, const char *value)
{
   ast_copy_string(chan->macrocontext, value, sizeof(chan->macrocontext));
}
const char *ast_channel_macroexten(const struct ast_channel *chan)
{
   return chan->macroexten;
}
void ast_channel_macroexten_set(struct ast_channel *chan, const char *value)
{
   ast_copy_string(chan->macroexten, value, sizeof(chan->macroexten));
}

char ast_channel_dtmf_digit_to_emulate(const struct ast_channel *chan)
{
   return chan->dtmf_digit_to_emulate;
}
void ast_channel_dtmf_digit_to_emulate_set(struct ast_channel *chan, char value)
{
   chan->dtmf_digit_to_emulate = value;
}

char ast_channel_sending_dtmf_digit(const struct ast_channel *chan)
{
   return chan->sending_dtmf_digit;
}
void ast_channel_sending_dtmf_digit_set(struct ast_channel *chan, char value)
{
   chan->sending_dtmf_digit = value;
}

struct timeval ast_channel_sending_dtmf_tv(const struct ast_channel *chan)
{
   return chan->sending_dtmf_tv;
}
void ast_channel_sending_dtmf_tv_set(struct ast_channel *chan, struct timeval value)
{
   chan->sending_dtmf_tv = value;
}

enum ama_flags ast_channel_amaflags(const struct ast_channel *chan)
{
   return chan->amaflags;
}

void ast_channel_amaflags_set(struct ast_channel *chan, enum ama_flags value)
{
   if (chan->amaflags == value) {
      return;
   }
   chan->amaflags = value;
   ast_channel_publish_snapshot(chan);
}
int ast_channel_fdno(const struct ast_channel *chan)
{
   return chan->fdno;
}
void ast_channel_fdno_set(struct ast_channel *chan, int value)
{
   chan->fdno = value;
}
int ast_channel_hangupcause(const struct ast_channel *chan)
{
   return chan->hangupcause;
}
void ast_channel_hangupcause_set(struct ast_channel *chan, int value)
{
   chan->hangupcause = value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_HANGUP);
}
int ast_channel_macropriority(const struct ast_channel *chan)
{
   return chan->macropriority;
}
void ast_channel_macropriority_set(struct ast_channel *chan, int value)
{
   chan->macropriority = value;
}
int ast_channel_priority(const struct ast_channel *chan)
{
   return chan->priority;
}
void ast_channel_priority_set(struct ast_channel *chan, int value)
{
   chan->priority = value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_DIALPLAN);
}
int ast_channel_rings(const struct ast_channel *chan)
{
   return chan->rings;
}
void ast_channel_rings_set(struct ast_channel *chan, int value)
{
   chan->rings = value;
}
int ast_channel_streamid(const struct ast_channel *chan)
{
   return chan->streamid;
}
void ast_channel_streamid_set(struct ast_channel *chan, int value)
{
   chan->streamid = value;
}
int ast_channel_timingfd(const struct ast_channel *chan)
{
   return chan->timingfd;
}
void ast_channel_timingfd_set(struct ast_channel *chan, int value)
{
   chan->timingfd = value;
}
int ast_channel_visible_indication(const struct ast_channel *chan)
{
   return chan->visible_indication;
}
void ast_channel_visible_indication_set(struct ast_channel *chan, int value)
{
   chan->visible_indication = value;
}
int ast_channel_hold_state(const struct ast_channel *chan)
{
   return chan->hold_state;
}
void ast_channel_hold_state_set(struct ast_channel *chan, int value)
{
   chan->hold_state = value;
}
int ast_channel_vstreamid(const struct ast_channel *chan)
{
   return chan->vstreamid;
}
void ast_channel_vstreamid_set(struct ast_channel *chan, int value)
{
   chan->vstreamid = value;
}
unsigned short ast_channel_transfercapability(const struct ast_channel *chan)
{
   return chan->transfercapability;
}
void ast_channel_transfercapability_set(struct ast_channel *chan, unsigned short value)
{
   chan->transfercapability = value;
}
unsigned int ast_channel_emulate_dtmf_duration(const struct ast_channel *chan)
{
   return chan->emulate_dtmf_duration;
}
void ast_channel_emulate_dtmf_duration_set(struct ast_channel *chan, unsigned int value)
{
   chan->emulate_dtmf_duration = value;
}
unsigned int ast_channel_fin(const struct ast_channel *chan)
{
   return chan->fin;
}
void ast_channel_fin_set(struct ast_channel *chan, unsigned int value)
{
   chan->fin = value;
}
unsigned int ast_channel_fout(const struct ast_channel *chan)
{
   return chan->fout;
}
void ast_channel_fout_set(struct ast_channel *chan, unsigned int value)
{
   chan->fout = value;
}
unsigned long ast_channel_insmpl(const struct ast_channel *chan)
{
   return chan->insmpl;
}
void ast_channel_insmpl_set(struct ast_channel *chan, unsigned long value)
{
   chan->insmpl = value;
}
unsigned long ast_channel_outsmpl(const struct ast_channel *chan)
{
   return chan->outsmpl;
}
void ast_channel_outsmpl_set(struct ast_channel *chan, unsigned long value)
{
   chan->outsmpl = value;
}
void *ast_channel_generatordata(const struct ast_channel *chan)
{
   return chan->generatordata;
}
void ast_channel_generatordata_set(struct ast_channel *chan, void *value)
{
   chan->generatordata = value;
}
void *ast_channel_music_state(const struct ast_channel *chan)
{
   return chan->music_state;
}
void ast_channel_music_state_set(struct ast_channel *chan, void *value)
{
   chan->music_state = value;
}
void *ast_channel_tech_pvt(const struct ast_channel *chan)
{
   return chan->tech_pvt;
}
void ast_channel_tech_pvt_set(struct ast_channel *chan, void *value)
{
   chan->tech_pvt = value;
}
void *ast_channel_timingdata(const struct ast_channel *chan)
{
   return chan->timingdata;
}
void ast_channel_timingdata_set(struct ast_channel *chan, void *value)
{
   chan->timingdata = value;
}
struct ast_audiohook_list *ast_channel_audiohooks(const struct ast_channel *chan)
{
   return chan->audiohooks;
}
void ast_channel_audiohooks_set(struct ast_channel *chan, struct ast_audiohook_list *value)
{
   chan->audiohooks = value;
}
struct ast_cdr *ast_channel_cdr(const struct ast_channel *chan)
{
   return chan->cdr;
}
void ast_channel_cdr_set(struct ast_channel *chan, struct ast_cdr *value)
{
   chan->cdr = value;
}
struct ast_channel *ast_channel_masq(const struct ast_channel *chan)
{
   return chan->masq;
}
void ast_channel_masq_set(struct ast_channel *chan, struct ast_channel *value)
{
   chan->masq = value;
}
struct ast_channel *ast_channel_masqr(const struct ast_channel *chan)
{
   return chan->masqr;
}
void ast_channel_masqr_set(struct ast_channel *chan, struct ast_channel *value)
{
   chan->masqr = value;
}
struct ast_channel_monitor *ast_channel_monitor(const struct ast_channel *chan)
{
   return chan->monitor;
}
void ast_channel_monitor_set(struct ast_channel *chan, struct ast_channel_monitor *value)
{
   chan->monitor = value;
}
struct ast_filestream *ast_channel_stream(const struct ast_channel *chan)
{
   return chan->stream;
}
void ast_channel_stream_set(struct ast_channel *chan, struct ast_filestream *value)
{
   chan->stream = value;
}
struct ast_filestream *ast_channel_vstream(const struct ast_channel *chan)
{
   return chan->vstream;
}
void ast_channel_vstream_set(struct ast_channel *chan, struct ast_filestream *value)
{
   chan->vstream = value;
}
struct ast_format_cap *ast_channel_nativeformats(const struct ast_channel *chan)
{
   return chan->nativeformats;
}

static void channel_set_default_streams(struct ast_channel *chan)
{
   enum ast_media_type type;

   ast_assert(chan != NULL);

   for (type = AST_MEDIA_TYPE_UNKNOWN; type < AST_MEDIA_TYPE_END; type++) {
      if (chan->stream_topology) {
         chan->default_streams[type] =
            ast_stream_topology_get_first_stream_by_type(chan->stream_topology, type);
      } else {
         chan->default_streams[type] = NULL;
      }
   }
}

void ast_channel_internal_set_stream_topology(struct ast_channel *chan,
   struct ast_stream_topology *topology)
{
   ast_stream_topology_free(chan->stream_topology);
   chan->stream_topology = topology;
   channel_set_default_streams(chan);
}

void ast_channel_internal_set_stream_topology_change_source(
   struct ast_channel *chan, void *change_source)
{
   chan->stream_topology_change_source = change_source;
}

void *ast_channel_get_stream_topology_change_source(struct ast_channel *chan)
{
   return chan->stream_topology_change_source;
}

void ast_channel_nativeformats_set(struct ast_channel *chan,
   struct ast_format_cap *value)
{
   SCOPE_ENTER(2, "%s: %sFormats: %s\n", S_OR(ast_channel_name(chan), "<initializing>"),
      S_COR(ast_channel_is_multistream(chan), "Multistream", ""),
      ast_str_tmp(128, ast_format_cap_get_names(value, &STR_TMP)));

   ast_assert(chan != NULL);

   ao2_replace(chan->nativeformats, value);

   /* If chan->stream_topology is NULL, the channel is being destroyed
    * and topology is destroyed.
    */
   if (!chan->stream_topology) {
      SCOPE_EXIT_RTN("Channel is being initialized or destroyed\n");
   }

   if (!ast_channel_is_multistream(chan) || !value) {
      struct ast_stream_topology *new_topology;

      new_topology = ast_stream_topology_create_from_format_cap(value);
      ast_channel_internal_set_stream_topology(chan, new_topology);
      SCOPE_EXIT_RTN("New %stopology set\n", value ? "" : "empty ");
   }
   SCOPE_EXIT_RTN("Set native formats but not topology\n");
}

struct ast_framehook_list *ast_channel_framehooks(const struct ast_channel *chan)
{
   return chan->framehooks;
}
void ast_channel_framehooks_set(struct ast_channel *chan, struct ast_framehook_list *value)
{
   chan->framehooks = value;
}
struct ast_generator *ast_channel_generator(const struct ast_channel *chan)
{
   return chan->generator;
}
void ast_channel_generator_set(struct ast_channel *chan, struct ast_generator *value)
{
   chan->generator = value;
}
struct ast_pbx *ast_channel_pbx(const struct ast_channel *chan)
{
   return chan->pbx;
}
void ast_channel_pbx_set(struct ast_channel *chan, struct ast_pbx *value)
{
   chan->pbx = value;
}
struct ast_sched_context *ast_channel_sched(const struct ast_channel *chan)
{
   return chan->sched;
}
void ast_channel_sched_set(struct ast_channel *chan, struct ast_sched_context *value)
{
   chan->sched = value;
}
struct ast_timer *ast_channel_timer(const struct ast_channel *chan)
{
   return chan->timer;
}
void ast_channel_timer_set(struct ast_channel *chan, struct ast_timer *value)
{
   chan->timer = value;
}
struct ast_tone_zone *ast_channel_zone(const struct ast_channel *chan)
{
   return chan->zone;
}
void ast_channel_zone_set(struct ast_channel *chan, struct ast_tone_zone *value)
{
   chan->zone = value;
}
struct ast_trans_pvt *ast_channel_readtrans(const struct ast_channel *chan)
{
   return chan->readtrans;
}
void ast_channel_readtrans_set(struct ast_channel *chan, struct ast_trans_pvt *value)
{
   chan->readtrans = value;
}
struct ast_trans_pvt *ast_channel_writetrans(const struct ast_channel *chan)
{
   return chan->writetrans;
}
void ast_channel_writetrans_set(struct ast_channel *chan, struct ast_trans_pvt *value)
{
   chan->writetrans = value;
}
const struct ast_channel_tech *ast_channel_tech(const struct ast_channel *chan)
{
   return chan->tech;
}
void ast_channel_tech_set(struct ast_channel *chan, const struct ast_channel_tech *value)
{
   if (value->read_stream || value->write_stream) {
      ast_assert(value->read_stream && value->write_stream);
   }

   chan->tech = value;
}
enum ast_channel_adsicpe ast_channel_adsicpe(const struct ast_channel *chan)
{
   return chan->adsicpe;
}
void ast_channel_adsicpe_set(struct ast_channel *chan, enum ast_channel_adsicpe value)
{
   chan->adsicpe = value;
}
enum ast_channel_state ast_channel_state(const struct ast_channel *chan)
{
   return chan->state;
}
ast_callid ast_channel_callid(const struct ast_channel *chan)
{
   return chan->callid;
}
void ast_channel_callid_set(struct ast_channel *chan, ast_callid callid)
{
   char call_identifier_from[AST_CALLID_BUFFER_LENGTH];
   char call_identifier_to[AST_CALLID_BUFFER_LENGTH];
   call_identifier_from[0] = '\0';
   ast_callid_strnprint(call_identifier_to, sizeof(call_identifier_to), callid);
   if (chan->callid) {
      ast_callid_strnprint(call_identifier_from, sizeof(call_identifier_from), chan->callid);
      ast_debug(3, "Channel Call ID changing from %s to %s\n", call_identifier_from, call_identifier_to);
   }

   chan->callid = callid;

   ast_test_suite_event_notify("CallIDChange",
      "State: CallIDChange\r\n"
      "Channel: %s\r\n"
      "CallID: %s\r\n"
      "PriorCallID: %s",
      ast_channel_name(chan),
      call_identifier_to,
      call_identifier_from);
}

void ast_channel_state_set(struct ast_channel *chan, enum ast_channel_state value)
{
   chan->state = value;
}
void ast_channel_set_oldwriteformat(struct ast_channel *chan, struct ast_format *format)
{
   ao2_replace(chan->oldwriteformat, format);
}
void ast_channel_set_rawreadformat(struct ast_channel *chan, struct ast_format *format)
{
   ao2_replace(chan->rawreadformat, format);
}
void ast_channel_set_rawwriteformat(struct ast_channel *chan, struct ast_format *format)
{
   ao2_replace(chan->rawwriteformat, format);
}
void ast_channel_set_readformat(struct ast_channel *chan, struct ast_format *format)
{
   ao2_replace(chan->readformat, format);
}
void ast_channel_set_writeformat(struct ast_channel *chan, struct ast_format *format)
{
   ao2_replace(chan->writeformat, format);
}
struct ast_format *ast_channel_oldwriteformat(struct ast_channel *chan)
{
   return chan->oldwriteformat;
}
struct ast_format *ast_channel_rawreadformat(struct ast_channel *chan)
{
   return chan->rawreadformat;
}
struct ast_format *ast_channel_rawwriteformat(struct ast_channel *chan)
{
   return chan->rawwriteformat;
}
struct ast_format *ast_channel_readformat(struct ast_channel *chan)
{
   return chan->readformat;
}
struct ast_format *ast_channel_writeformat(struct ast_channel *chan)
{
   return chan->writeformat;
}
struct ast_hangup_handler_list *ast_channel_hangup_handlers(struct ast_channel *chan)
{
   return &chan->hangup_handlers;
}
struct ast_datastore_list *ast_channel_datastores(struct ast_channel *chan)
{
   return &chan->datastores;
}
struct ast_autochan_list *ast_channel_autochans(struct ast_channel *chan)
{
   return &chan->autochans;
}
struct ast_readq_list *ast_channel_readq(struct ast_channel *chan)
{
   return &chan->readq;
}
struct ast_frame *ast_channel_dtmff(struct ast_channel *chan)
{
   return &chan->dtmff;
}
struct ast_jb *ast_channel_jb(struct ast_channel *chan)
{
   return &chan->jb;
}
struct ast_party_caller *ast_channel_caller(struct ast_channel *chan)
{
   return &chan->caller;
}
struct ast_party_connected_line *ast_channel_connected(struct ast_channel *chan)
{
   return &chan->connected;
}
struct ast_party_connected_line *ast_channel_connected_indicated(struct ast_channel *chan)
{
   return &chan->connected_indicated;
}
struct ast_party_id ast_channel_connected_effective_id(struct ast_channel *chan)
{
   return ast_party_id_merge(&chan->connected.id, &chan->connected.priv);
}
struct ast_party_dialed *ast_channel_dialed(struct ast_channel *chan)
{
   return &chan->dialed;
}
struct ast_party_redirecting *ast_channel_redirecting(struct ast_channel *chan)
{
   return &chan->redirecting;
}
struct ast_party_id ast_channel_redirecting_effective_orig(struct ast_channel *chan)
{
   return ast_party_id_merge(&chan->redirecting.orig, &chan->redirecting.priv_orig);
}
struct ast_party_id ast_channel_redirecting_effective_from(struct ast_channel *chan)
{
   return ast_party_id_merge(&chan->redirecting.from, &chan->redirecting.priv_from);
}
struct ast_party_id ast_channel_redirecting_effective_to(struct ast_channel *chan)
{
   return ast_party_id_merge(&chan->redirecting.to, &chan->redirecting.priv_to);
}
struct timeval *ast_channel_dtmf_tv(struct ast_channel *chan)
{
   return &chan->dtmf_tv;
}
struct timeval *ast_channel_whentohangup(struct ast_channel *chan)
{
   return &chan->whentohangup;
}
struct varshead *ast_channel_varshead(struct ast_channel *chan)
{
   return &chan->varshead;
}
void ast_channel_dtmff_set(struct ast_channel *chan, struct ast_frame *value)
{
   chan->dtmff = *value;
}
void ast_channel_jb_set(struct ast_channel *chan, struct ast_jb *value)
{
   chan->jb = *value;
}
void ast_channel_caller_set(struct ast_channel *chan, struct ast_party_caller *value)
{
   chan->caller = *value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_CALLER);
}
void ast_channel_connected_set(struct ast_channel *chan, struct ast_party_connected_line *value)
{
   chan->connected = *value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_CONNECTED);
}
void ast_channel_dialed_set(struct ast_channel *chan, struct ast_party_dialed *value)
{
   chan->dialed = *value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_CALLER);
}
void ast_channel_redirecting_set(struct ast_channel *chan, struct ast_party_redirecting *value)
{
   chan->redirecting = *value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_CALLER);
}
void ast_channel_dtmf_tv_set(struct ast_channel *chan, struct timeval *value)
{
   chan->dtmf_tv = *value;
}
void ast_channel_whentohangup_set(struct ast_channel *chan, struct timeval *value)
{
   chan->whentohangup = *value;
}
void ast_channel_varshead_set(struct ast_channel *chan, struct varshead *value)
{
   chan->varshead = *value;
}
struct timeval ast_channel_creationtime(struct ast_channel *chan)
{
   return chan->creationtime;
}
void ast_channel_creationtime_set(struct ast_channel *chan, struct timeval *value)
{
   chan->creationtime = *value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_BASE);
}

struct timeval ast_channel_answertime(struct ast_channel *chan)
{
   return chan->answertime;
}

void ast_channel_answertime_set(struct ast_channel *chan, struct timeval *value)
{
   chan->answertime = *value;
}

/* Evil softhangup accessors */
int ast_channel_softhangup_internal_flag(struct ast_channel *chan)
{
   return chan->softhangup;
}
void ast_channel_softhangup_internal_flag_set(struct ast_channel *chan, int value)
{
   chan->softhangup = value;
}
void ast_channel_softhangup_internal_flag_add(struct ast_channel *chan, int value)
{
   chan->softhangup |= value;
}
void ast_channel_softhangup_internal_flag_clear(struct ast_channel *chan, int value)
{
   chan ->softhangup &= ~value;
}

int ast_channel_unbridged_nolock(struct ast_channel *chan)
{
   return chan->unbridged;
}

int ast_channel_unbridged(struct ast_channel *chan)
{
   int res;
   ast_channel_lock(chan);
   res = ast_channel_unbridged_nolock(chan);
   ast_channel_unlock(chan);
   return res;
}

void ast_channel_set_unbridged_nolock(struct ast_channel *chan, int value)
{
   chan->unbridged = !!value;
   ast_queue_frame(chan, &ast_null_frame);
}

void ast_channel_set_unbridged(struct ast_channel *chan, int value)
{
   ast_channel_lock(chan);
   ast_channel_set_unbridged_nolock(chan, value);
   ast_channel_unlock(chan);
}

int ast_channel_is_t38_active_nolock(struct ast_channel *chan)
{
   return chan->is_t38_active;
}

int ast_channel_is_t38_active(struct ast_channel *chan)
{
   int res;

   ast_channel_lock(chan);
   res = ast_channel_is_t38_active_nolock(chan);
   ast_channel_unlock(chan);
   return res;
}

void ast_channel_set_is_t38_active_nolock(struct ast_channel *chan, int is_t38_active)
{
   chan->is_t38_active = !!is_t38_active;
}

void ast_channel_set_is_t38_active(struct ast_channel *chan, int is_t38_active)
{
   ast_channel_lock(chan);
   ast_channel_set_is_t38_active_nolock(chan, is_t38_active);
   ast_channel_unlock(chan);
}

void ast_channel_callid_cleanup(struct ast_channel *chan)
{
   chan->callid = 0;
}

/* Typedef accessors */
ast_group_t ast_channel_callgroup(const struct ast_channel *chan)
{
   return chan->callgroup;
}
void ast_channel_callgroup_set(struct ast_channel *chan, ast_group_t value)
{
   chan->callgroup = value;
}
ast_group_t ast_channel_pickupgroup(const struct ast_channel *chan)
{
   return chan->pickupgroup;
}
void ast_channel_pickupgroup_set(struct ast_channel *chan, ast_group_t value)
{
   chan->pickupgroup = value;
}
struct ast_namedgroups *ast_channel_named_callgroups(const struct ast_channel *chan)
{
   return chan->named_callgroups;
}
void ast_channel_named_callgroups_set(struct ast_channel *chan, struct ast_namedgroups *value)
{
   ast_unref_namedgroups(chan->named_callgroups);
   chan->named_callgroups = ast_ref_namedgroups(value);
}
struct ast_namedgroups *ast_channel_named_pickupgroups(const struct ast_channel *chan)
{
   return chan->named_pickupgroups;
}
void ast_channel_named_pickupgroups_set(struct ast_channel *chan, struct ast_namedgroups *value)
{
   ast_unref_namedgroups(chan->named_pickupgroups);
   chan->named_pickupgroups = ast_ref_namedgroups(value);
}

/* Alertpipe functions */
int ast_channel_alert_write(struct ast_channel *chan)
{
   return ast_alertpipe_write(chan->alertpipe);
}

ast_alert_status_t ast_channel_internal_alert_flush(struct ast_channel *chan)
{
   return ast_alertpipe_flush(chan->alertpipe);
}

ast_alert_status_t ast_channel_internal_alert_read(struct ast_channel *chan)
{
   return ast_alertpipe_read(chan->alertpipe);
}

int ast_channel_alert_writable(struct ast_channel *chan)
{
   return ast_alertpipe_writable(chan->alertpipe);
}

int ast_channel_internal_alert_readable(struct ast_channel *chan)
{
   return ast_alertpipe_readable(chan->alertpipe);
}

void ast_channel_internal_alertpipe_clear(struct ast_channel *chan)
{
   ast_alertpipe_clear(chan->alertpipe);
}

void ast_channel_internal_alertpipe_close(struct ast_channel *chan)
{
   ast_alertpipe_close(chan->alertpipe);
}

int ast_channel_internal_alertpipe_init(struct ast_channel *chan)
{
   return ast_alertpipe_init(chan->alertpipe);
}

int ast_channel_internal_alert_readfd(struct ast_channel *chan)
{
   return ast_alertpipe_readfd(chan->alertpipe);
}

void ast_channel_internal_alertpipe_swap(struct ast_channel *chan1, struct ast_channel *chan2)
{
   ast_alertpipe_swap(chan1->alertpipe, chan2->alertpipe);
}

/* file descriptor array accessors */
void ast_channel_internal_fd_set(struct ast_channel *chan, int which, int value)
{
   int pos;

   /* This ensures that if the vector has to grow with unused positions they will be
    * initialized to -1.
    */
   for (pos = AST_VECTOR_SIZE(&chan->fds); pos < which; pos++) {
      AST_VECTOR_REPLACE(&chan->fds, pos, -1);
   }

   AST_VECTOR_REPLACE(&chan->fds, which, value);
}
void ast_channel_internal_fd_clear(struct ast_channel *chan, int which)
{
   if (which >= AST_VECTOR_SIZE(&chan->fds)) {
      return;
   }

   AST_VECTOR_REPLACE(&chan->fds, which, -1);
}
void ast_channel_internal_fd_clear_all(struct ast_channel *chan)
{
   AST_VECTOR_RESET(&chan->fds, AST_VECTOR_ELEM_CLEANUP_NOOP);
}
int ast_channel_fd(const struct ast_channel *chan, int which)
{
   return (which >= AST_VECTOR_SIZE(&chan->fds)) ? -1 : AST_VECTOR_GET(&chan->fds, which);
}
int ast_channel_fd_isset(const struct ast_channel *chan, int which)
{
   return ast_channel_fd(chan, which) > -1;
}

int ast_channel_fd_count(const struct ast_channel *chan)
{
   return AST_VECTOR_SIZE(&chan->fds);
}

int ast_channel_fd_add(struct ast_channel *chan, int value)
{
   int pos = AST_EXTENDED_FDS;

   while (ast_channel_fd_isset(chan, pos)) {
      pos += 1;
   }

   AST_VECTOR_REPLACE(&chan->fds, pos, value);

   return pos;
}

pthread_t ast_channel_blocker(const struct ast_channel *chan)
{
   return chan->blocker;
}
void ast_channel_blocker_set(struct ast_channel *chan, pthread_t value)
{
   chan->blocker = value;
}

int ast_channel_blocker_tid(const struct ast_channel *chan)
{
   return chan->blocker_tid;
}
void ast_channel_blocker_tid_set(struct ast_channel *chan, int value)
{
   chan->blocker_tid = value;
}

ast_timing_func_t ast_channel_timingfunc(const struct ast_channel *chan)
{
   return chan->timingfunc;
}
void ast_channel_timingfunc_set(struct ast_channel *chan, ast_timing_func_t value)
{
   chan->timingfunc = value;
}

struct ast_bridge *ast_channel_internal_bridge(const struct ast_channel *chan)
{
   return chan->bridge;
}
void ast_channel_internal_bridge_set(struct ast_channel *chan, struct ast_bridge *value)
{
   chan->bridge = value;
   ast_channel_snapshot_invalidate_segment(chan, AST_CHANNEL_SNAPSHOT_INVALIDATE_BRIDGE);
   ast_channel_publish_snapshot(chan);
}

struct ast_bridge_channel *ast_channel_internal_bridge_channel(const struct ast_channel *chan)
{
   return chan->bridge_channel;
}
void ast_channel_internal_bridge_channel_set(struct ast_channel *chan, struct ast_bridge_channel *value)
{
   chan->bridge_channel = value;
}

struct ast_flags *ast_channel_flags(struct ast_channel *chan)
{
   return &chan->flags;
}

static int collect_names_cb(void *obj, void *arg, int flags) {
   struct ast_control_pvt_cause_code *cause_code = obj;
   struct ast_str **str = arg;

   ast_str_append(str, 0, "%s%s", (ast_str_strlen(*str) ? "," : ""), cause_code->chan_name);

   return 0;
}

struct ast_str *ast_channel_dialed_causes_channels(const struct ast_channel *chan)
{
   struct ast_str *chanlist = ast_str_create(128);

   if (!chanlist) {
      return NULL;
   }

   ao2_callback(chan->dialed_causes, 0, collect_names_cb, &chanlist);

   return chanlist;
}

struct ast_control_pvt_cause_code *ast_channel_dialed_causes_find(const struct ast_channel *chan, const char *chan_name)
{
   return ao2_find(chan->dialed_causes, chan_name, OBJ_KEY);
}

int ast_channel_dialed_causes_add(const struct ast_channel *chan, const struct ast_control_pvt_cause_code *cause_code, int datalen)
{
   struct ast_control_pvt_cause_code *ao2_cause_code;
   ao2_find(chan->dialed_causes, cause_code->chan_name, OBJ_KEY | OBJ_UNLINK | OBJ_NODATA);
   ao2_cause_code = ao2_alloc(datalen, NULL);

   if (ao2_cause_code) {
      memcpy(ao2_cause_code, cause_code, datalen);
      ao2_link(chan->dialed_causes, ao2_cause_code);
      ao2_ref(ao2_cause_code, -1);
      return 0;
   } else {
      return -1;
   }
}

void ast_channel_dialed_causes_clear(const struct ast_channel *chan)
{
   ao2_callback(chan->dialed_causes, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, NULL, NULL);
}

/* \brief Hash function for pvt cause code frames */
static int pvt_cause_hash_fn(const void *vpc, const int flags)
{
   const struct ast_control_pvt_cause_code *pc = vpc;
   return ast_str_hash(ast_tech_to_upper(ast_strdupa(pc->chan_name)));
}

/* \brief Comparison function for pvt cause code frames */
static int pvt_cause_cmp_fn(void *obj, void *vstr, int flags)
{
   struct ast_control_pvt_cause_code *pc = obj;
   char *str = ast_tech_to_upper(ast_strdupa(vstr));
   char *pc_str = ast_tech_to_upper(ast_strdupa(pc->chan_name));
   return !strcmp(pc_str, str) ? CMP_MATCH | CMP_STOP : 0;
}

#define DIALED_CAUSES_BUCKETS 37

struct ast_channel *__ast_channel_internal_alloc(void (*destructor)(void *obj), const struct ast_assigned_ids *assignedids, const struct ast_channel *requestor, const char *file, int line, const char *function)
{
   struct ast_channel *tmp;

   tmp = __ao2_alloc(sizeof(*tmp), destructor,
      AO2_ALLOC_OPT_LOCK_MUTEX, "", file, line, function);

   if (!tmp) {
      return NULL;
   }

   if ((ast_string_field_init(tmp, 128))) {
      return ast_channel_unref(tmp);
   }

   tmp->dialed_causes = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
      DIALED_CAUSES_BUCKETS, pvt_cause_hash_fn, NULL, pvt_cause_cmp_fn);
   if (!tmp->dialed_causes) {
      return ast_channel_unref(tmp);
   }

   /* set the creation time in the uniqueid */
   tmp->uniqueid.creation_time = time(NULL);
   tmp->uniqueid.creation_unique = ast_atomic_fetchadd_int(&uniqueint, 1);

   /* use provided id or default to historical {system-}time.# format */
   if (assignedids && !ast_strlen_zero(assignedids->uniqueid)) {
      ast_copy_string(tmp->uniqueid.unique_id, assignedids->uniqueid, sizeof(tmp->uniqueid.unique_id));
   } else if (ast_strlen_zero(ast_config_AST_SYSTEM_NAME)) {
      snprintf(tmp->uniqueid.unique_id, sizeof(tmp->uniqueid.unique_id), "%li.%d",
         (long)(tmp->uniqueid.creation_time),
         tmp->uniqueid.creation_unique);
   } else {
      snprintf(tmp->uniqueid.unique_id, sizeof(tmp->uniqueid.unique_id), "%s-%li.%d",
         ast_config_AST_SYSTEM_NAME,
         (long)(tmp->uniqueid.creation_time),
         tmp->uniqueid.creation_unique);
   }

   /* copy linked id from parent channel if known */
   if (requestor) {
      tmp->linkedid = requestor->linkedid;
   } else {
      tmp->linkedid = tmp->uniqueid;
   }

   AST_VECTOR_INIT(&tmp->fds, AST_MAX_FDS);

   /* Force all channel snapshot segments to be created on first use, so we don't have to check if
    * an old snapshot exists.
    */
   ast_set_flag(&tmp->snapshot_segment_flags, AST_FLAGS_ALL);

   return tmp;
}

struct ast_channel *ast_channel_internal_oldest_linkedid(struct ast_channel *a, struct ast_channel *b)
{
   ast_assert(a->linkedid.creation_time != 0);
   ast_assert(b->linkedid.creation_time != 0);

   if (a->linkedid.creation_time < b->linkedid.creation_time) {
      return a;
   }
   if (b->linkedid.creation_time < a->linkedid.creation_time) {
      return b;
   }
   if (a->linkedid.creation_unique < b->linkedid.creation_unique) {
      return a;
   }
   return b;
}

void ast_channel_internal_copy_linkedid(struct ast_channel *dest, struct ast_channel *source)
{
   if (dest->linkedid.creation_time == source->linkedid.creation_time
      && dest->linkedid.creation_unique == source->linkedid.creation_unique
      && !strcmp(dest->linkedid.unique_id, source->linkedid.unique_id)) {
      return;
   }
   dest->linkedid = source->linkedid;
   ast_channel_snapshot_invalidate_segment(dest, AST_CHANNEL_SNAPSHOT_INVALIDATE_PEER);
   ast_channel_publish_snapshot(dest);
}

void ast_channel_internal_swap_uniqueid_and_linkedid(struct ast_channel *a, struct ast_channel *b)
{
   struct ast_channel_id temp;

   /* This operation is used as part of masquerading and so does not invalidate the peer
    * segment. This is due to the masquerade process invalidating all segments.
    */

   temp = a->uniqueid;
   a->uniqueid = b->uniqueid;
   b->uniqueid = temp;

   temp = a->linkedid;
   a->linkedid = b->linkedid;
   b->linkedid = temp;
}

void ast_channel_internal_swap_topics(struct ast_channel *a, struct ast_channel *b)
{
   struct stasis_topic *topic;
   struct stasis_forward *forward;

   topic = a->topic;
   a->topic = b->topic;
   b->topic = topic;

   forward = a->channel_forward;
   a->channel_forward = b->channel_forward;
   b->channel_forward = forward;
}

void ast_channel_internal_swap_endpoint_forward(struct ast_channel *a, struct ast_channel *b)
{
   struct stasis_forward *temp;

   temp = a->endpoint_forward;
   a->endpoint_forward = b->endpoint_forward;
   b->endpoint_forward = temp;
}

void ast_channel_internal_swap_snapshots(struct ast_channel *a, struct ast_channel *b)
{
   struct ast_channel_snapshot *snapshot;

   snapshot = a->snapshot;
   a->snapshot = b->snapshot;
   b->snapshot = snapshot;
}

void ast_channel_internal_set_fake_ids(struct ast_channel *chan, const char *uniqueid, const char *linkedid)
{
   ast_copy_string(chan->uniqueid.unique_id, uniqueid, sizeof(chan->uniqueid.unique_id));
   ast_copy_string(chan->linkedid.unique_id, linkedid, sizeof(chan->linkedid.unique_id));
}

void ast_channel_internal_cleanup(struct ast_channel *chan)
{
   if (chan->dialed_causes) {
      ao2_t_ref(chan->dialed_causes, -1,
         "done with dialed causes since the channel is going away");
      chan->dialed_causes = NULL;
   }

   ast_string_field_free_memory(chan);

   chan->channel_forward = stasis_forward_cancel(chan->channel_forward);
   chan->endpoint_forward = stasis_forward_cancel(chan->endpoint_forward);

   ao2_cleanup(chan->topic);
   chan->topic = NULL;

   ast_channel_internal_set_stream_topology(chan, NULL);

   AST_VECTOR_FREE(&chan->fds);
}

void ast_channel_internal_finalize(struct ast_channel *chan)
{
   chan->finalized = 1;
}

int ast_channel_internal_is_finalized(struct ast_channel *chan)
{
   return chan->finalized;
}

struct stasis_topic *ast_channel_topic(struct ast_channel *chan)
{
   if (!chan) {
      return ast_channel_topic_all();
   }

   return chan->topic;
}

int ast_channel_forward_endpoint(struct ast_channel *chan,
   struct ast_endpoint *endpoint)
{
   ast_assert(chan != NULL);
   ast_assert(endpoint != NULL);

   chan->endpoint_forward =
      stasis_forward_all(ast_channel_topic(chan),
         ast_endpoint_topic(endpoint));
   if (!chan->endpoint_forward) {
      return -1;
   }

   return 0;
}

int ast_channel_internal_setup_topics(struct ast_channel *chan)
{
   char *topic_name;
   int ret;
   ast_assert(chan->topic == NULL);

   if (ast_strlen_zero(chan->uniqueid.unique_id)) {
      static int dummy_id;
      ret = ast_asprintf(&topic_name, "channel:dummy-%d", ast_atomic_fetchadd_int(&dummy_id, +1));
   } else {
      ret = ast_asprintf(&topic_name, "channel:%s", chan->uniqueid.unique_id);
   }

   if (ret < 0) {
      return -1;
   }

   chan->topic = stasis_topic_create(topic_name);
   ast_free(topic_name);
   if (!chan->topic) {
      return -1;
   }

   chan->channel_forward = stasis_forward_all(ast_channel_topic(chan),
      ast_channel_topic_all());
   if (!chan->channel_forward) {
      ao2_ref(chan->topic, -1);
      chan->topic = NULL;
      return -1;
   }

   return 0;
}

AST_THREADSTORAGE(channel_errno);

void ast_channel_internal_errno_set(enum ast_channel_error error)
{
   enum ast_channel_error *error_code = ast_threadstorage_get(&channel_errno, sizeof(*error_code));
   if (!error_code) {
      return;
   }

   *error_code = error;
}

enum ast_channel_error ast_channel_internal_errno(void)
{
   enum ast_channel_error *error_code = ast_threadstorage_get(&channel_errno, sizeof(*error_code));
   if (!error_code) {
      return AST_CHANNEL_ERROR_UNKNOWN;
   }

   return *error_code;
}

struct ast_stream_topology *ast_channel_get_stream_topology(
   const struct ast_channel *chan)
{
   ast_assert(chan != NULL);

   return chan->stream_topology;
}

struct ast_stream_topology *ast_channel_set_stream_topology(struct ast_channel *chan,
   struct ast_stream_topology *topology)
{
   struct ast_stream_topology *new_topology;
   SCOPE_ENTER(1, "%s: %s\n", ast_channel_name(chan),
      ast_str_tmp(256, ast_stream_topology_to_str(topology, &STR_TMP)));

   ast_assert(chan != NULL);

   /* A non-MULTISTREAM channel can't manipulate topology directly */
   ast_assert(ast_channel_is_multistream(chan));

   /* Unless the channel is being destroyed, we always want a topology on
    * it even if its empty.
    */
   if (!topology) {
      new_topology = ast_stream_topology_alloc();
   } else {
      new_topology = topology;
   }

   if (new_topology) {
      ast_channel_internal_set_stream_topology(chan, new_topology);
   }

   SCOPE_EXIT_RTN_VALUE(new_topology, "Used %s topology\n", topology ? "provided" : "empty");
}

struct ast_stream *ast_channel_get_default_stream(struct ast_channel *chan,
   enum ast_media_type type)
{
   ast_assert(chan != NULL);
   ast_assert(type < AST_MEDIA_TYPE_END);

   return chan->default_streams[type];
}

void ast_channel_internal_swap_stream_topology(struct ast_channel *chan1,
   struct ast_channel *chan2)
{
   struct ast_stream_topology *tmp_topology;

   ast_assert(chan1 != NULL && chan2 != NULL);

   tmp_topology = chan1->stream_topology;
   chan1->stream_topology = chan2->stream_topology;
   chan2->stream_topology = tmp_topology;

   channel_set_default_streams(chan1);
   channel_set_default_streams(chan2);
}

int ast_channel_is_multistream(struct ast_channel *chan)
{
   return (chan && chan->tech && chan->tech->read_stream && chan->tech->write_stream);
}

struct ast_channel_snapshot *ast_channel_snapshot(const struct ast_channel *chan)
{
   return chan->snapshot;
}

void ast_channel_snapshot_set(struct ast_channel *chan, struct ast_channel_snapshot *snapshot)
{
   ao2_cleanup(chan->snapshot);
   chan->snapshot = ao2_bump(snapshot);
}

struct ast_flags *ast_channel_snapshot_segment_flags(struct ast_channel *chan)
{
   return &chan->snapshot_segment_flags;
}