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Asterisk developer's documentation


channel.h

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2006, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  * \brief General Asterisk PBX channel definitions.
00021  * \par See also:
00022  *  \arg \ref Def_Channel
00023  *  \arg \ref channel_drivers
00024  */
00025 
00026 /*! \page Def_Channel Asterisk Channels
00027    \par What is a Channel?
00028    A phone call through Asterisk consists of an incoming
00029    connection and an outbound connection. Each call comes
00030    in through a channel driver that supports one technology,
00031    like SIP, DAHDI, IAX2 etc.
00032    \par
00033    Each channel driver, technology, has it's own private
00034    channel or dialog structure, that is technology-dependent.
00035    Each private structure is "owned" by a generic Asterisk
00036    channel structure, defined in channel.h and handled by
00037    channel.c .
00038    \par Call scenario
00039    This happens when an incoming call arrives to Asterisk
00040    -# Call arrives on a channel driver interface
00041    -# Channel driver creates a PBX channel and starts a
00042       pbx thread on the channel
00043    -# The dial plan is executed
00044    -# At this point at least two things can happen:
00045       -# The call is answered by Asterisk and
00046          Asterisk plays a media stream or reads media
00047       -# The dial plan forces Asterisk to create an outbound
00048          call somewhere with the dial (see \ref app_dial.c)
00049          application
00050    .
00051 
00052    \par Bridging channels
00053    If Asterisk dials out this happens:
00054    -# Dial creates an outbound PBX channel and asks one of the
00055       channel drivers to create a call
00056    -# When the call is answered, Asterisk bridges the media streams
00057       so the caller on the first channel can speak with the callee
00058       on the second, outbound channel
00059    -# In some cases where we have the same technology on both
00060       channels and compatible codecs, a native bridge is used.
00061       In a native bridge, the channel driver handles forwarding
00062       of incoming audio to the outbound stream internally, without
00063       sending audio frames through the PBX.
00064    -# In SIP, theres an "external native bridge" where Asterisk
00065       redirects the endpoint, so audio flows directly between the
00066       caller's phone and the callee's phone. Signalling stays in
00067       Asterisk in order to be able to provide a proper CDR record
00068       for the call.
00069 
00070 
00071    \par Masquerading channels
00072    In some cases, a channel can masquerade itself into another
00073    channel. This happens frequently in call transfers, where
00074    a new channel takes over a channel that is already involved
00075    in a call. The new channel sneaks in and takes over the bridge
00076    and the old channel, now a zombie, is hung up.
00077 
00078    \par Reference
00079    \arg channel.c - generic functions
00080    \arg channel.h - declarations of functions, flags and structures
00081    \arg translate.h - Transcoding support functions
00082    \arg \ref channel_drivers - Implemented channel drivers
00083    \arg \ref Def_Frame Asterisk Multimedia Frames
00084    \arg \ref Def_Bridge
00085 
00086 */
00087 /*! \page Def_Bridge Asterisk Channel Bridges
00088 
00089    In Asterisk, there's several media bridges.
00090 
00091    The Core bridge handles two channels (a "phone call") and bridge
00092    them together.
00093 
00094    The conference bridge (meetme) handles several channels simultaneously
00095    with the support of an external timer (DAHDI timer). This is used
00096    not only by the Conference application (meetme) but also by the
00097    page application and the SLA system introduced in 1.4.
00098    The conference bridge does not handle video.
00099 
00100    When two channels of the same type connect, the channel driver
00101    or the media subsystem used by the channel driver (i.e. RTP)
00102    can create a native bridge without sending media through the
00103    core.
00104 
00105    Native briding can be disabled by a number of reasons,
00106    like DTMF being needed by the core or codecs being incompatible
00107    so a transcoding module is needed.
00108 
00109 References:
00110    \li \see ast_channel_early_bridge()
00111    \li \see ast_channel_bridge()
00112    \li \see app_meetme.c
00113    \li \ref AstRTPbridge
00114    \li \see ast_rtp_bridge()
00115    \li \ref Def_Channel
00116 */
00117 
00118 /*! \page AstFileDesc File descriptors
00119    Asterisk File descriptors are connected to each channel (see \ref Def_Channel)
00120    in the \ref ast_channel structure.
00121 */
00122 
00123 #ifndef _ASTERISK_CHANNEL_H
00124 #define _ASTERISK_CHANNEL_H
00125 
00126 #include "asterisk/abstract_jb.h"
00127 
00128 #include "asterisk/poll-compat.h"
00129 
00130 #if defined(__cplusplus) || defined(c_plusplus)
00131 extern "C" {
00132 #endif
00133 
00134 #define AST_MAX_EXTENSION  80 /*!< Max length of an extension */
00135 #define AST_MAX_CONTEXT    80 /*!< Max length of a context */
00136 #define AST_CHANNEL_NAME   80 /*!< Max length of an ast_channel name */
00137 #define MAX_LANGUAGE    20 /*!< Max length of the language setting */
00138 #define MAX_MUSICCLASS     80 /*!< Max length of the music class setting */
00139 
00140 #include "asterisk/frame.h"
00141 #include "asterisk/sched.h"
00142 #include "asterisk/chanvars.h"
00143 #include "asterisk/config.h"
00144 #include "asterisk/lock.h"
00145 #include "asterisk/cdr.h"
00146 #include "asterisk/utils.h"
00147 #include "asterisk/linkedlists.h"
00148 #include "asterisk/stringfields.h"
00149 #include "asterisk/datastore.h"
00150 
00151 #define DATASTORE_INHERIT_FOREVER   INT_MAX
00152 
00153 #define AST_MAX_FDS     10
00154 /*
00155  * We have AST_MAX_FDS file descriptors in a channel.
00156  * Some of them have a fixed use:
00157  */
00158 #define AST_ALERT_FD (AST_MAX_FDS-1)      /*!< used for alertpipe */
00159 #define AST_TIMING_FD   (AST_MAX_FDS-2)      /*!< used for timingfd */
00160 #define AST_AGENT_FD (AST_MAX_FDS-3)      /*!< used by agents for pass through */
00161 #define AST_GENERATOR_FD   (AST_MAX_FDS-4)   /*!< used by generator */
00162 
00163 enum ast_bridge_result {
00164    AST_BRIDGE_COMPLETE = 0,
00165    AST_BRIDGE_FAILED = -1,
00166    AST_BRIDGE_FAILED_NOWARN = -2,
00167    AST_BRIDGE_RETRY = -3,
00168 };
00169 
00170 typedef unsigned long long ast_group_t;
00171 
00172 /*! \todo Add an explanation of an Asterisk generator
00173 */
00174 struct ast_generator {
00175    void *(*alloc)(struct ast_channel *chan, void *params);
00176    void (*release)(struct ast_channel *chan, void *data);
00177    /*! This function gets called with the channel unlocked, but is called in
00178     *  the context of the channel thread so we know the channel is not going
00179     *  to disappear.  This callback is responsible for locking the channel as
00180     *  necessary. */
00181    int (*generate)(struct ast_channel *chan, void *data, int len, int samples);
00182    /*! This gets called when DTMF_END frames are read from the channel */
00183    void (*digit)(struct ast_channel *chan, char digit);
00184 };
00185 
00186 /*! \brief Structure for all kinds of caller ID identifications.
00187  * \note All string fields here are malloc'ed, so they need to be
00188  * freed when the structure is deleted.
00189  * Also, NULL and "" must be considered equivalent.
00190  *
00191  * SIP and IAX2 has utf8 encoded Unicode caller ID names.
00192  * In some cases, we also have an alternative (RPID) E.164 number that can be used
00193  * as caller ID on numeric E.164 phone networks (DAHDI or SIP/IAX2 to pstn gateway).
00194  *
00195  * \todo Implement settings for transliteration between UTF8 caller ID names in
00196  *       to Ascii Caller ID's (DAHDI). Östen Åsklund might be transliterated into
00197  *  Osten Asklund or Oesten Aasklund depending upon language and person...
00198  *  We need automatic routines for incoming calls and static settings for
00199  *     our own accounts.
00200  */
00201 struct ast_callerid {
00202    char *cid_dnid;      /*!< Malloc'd Dialed Number Identifier */
00203    char *cid_num;    /*!< Malloc'd Caller Number */
00204    char *cid_name;      /*!< Malloc'd Caller Name (ASCII) */
00205    char *cid_ani;    /*!< Malloc'd ANI */
00206    char *cid_rdnis;  /*!< Malloc'd RDNIS */
00207    int cid_pres;     /*!< Callerid presentation/screening */
00208    int cid_ani2;     /*!< Callerid ANI 2 (Info digits) */
00209    int cid_ton;      /*!< Callerid Type of Number */
00210    int cid_tns;      /*!< Callerid Transit Network Select */
00211 };
00212 
00213 /*! \brief Typedef for a custom read function */
00214 typedef int (*ast_acf_read_fn_t)(struct ast_channel *, const char *, char *, char *, size_t);
00215 
00216 /*! \brief Typedef for a custom write function */
00217 typedef int (*ast_acf_write_fn_t)(struct ast_channel *, const char *, char *, const char *);
00218 
00219 /*! \brief Structure to handle passing func_channel_write info to channels via setoption */
00220 typedef struct {
00221    /*! \brief ast_chan_write_info_t version. Must be incremented if structure is changed */
00222    #define AST_CHAN_WRITE_INFO_T_VERSION 1
00223    uint32_t version;
00224    ast_acf_write_fn_t write_fn;
00225    struct ast_channel *chan;
00226    const char *function;
00227    char *data;
00228    const char *value;
00229 } ast_chan_write_info_t;
00230 
00231 /*! \brief
00232    Structure to describe a channel "technology", ie a channel driver
00233    See for examples:
00234    \arg chan_iax2.c - The Inter-Asterisk exchange protocol
00235    \arg chan_sip.c - The SIP channel driver
00236    \arg chan_dahdi.c - PSTN connectivity (TDM, PRI, T1/E1, FXO, FXS)
00237 
00238    If you develop your own channel driver, this is where you
00239    tell the PBX at registration of your driver what properties
00240    this driver supports and where different callbacks are
00241    implemented.
00242 */
00243 struct ast_channel_tech {
00244    const char * const type;
00245    const char * const description;
00246 
00247    int capabilities;    /*!< Bitmap of formats this channel can handle */
00248 
00249    int properties;         /*!< Technology Properties */
00250 
00251    /*! \brief Requester - to set up call data structures (pvt's) */
00252    struct ast_channel *(* const requester)(const char *type, int format, void *data, int *cause);
00253 
00254    int (* const devicestate)(void *data); /*!< Devicestate call back */
00255 
00256    /*!
00257     * \brief Start sending a literal DTMF digit
00258     *
00259     * \note The channel is not locked when this function gets called.
00260     */
00261    int (* const send_digit_begin)(struct ast_channel *chan, char digit);
00262 
00263    /*!
00264     * \brief Stop sending a literal DTMF digit
00265     *
00266     * \note The channel is not locked when this function gets called.
00267     */
00268    int (* const send_digit_end)(struct ast_channel *chan, char digit, unsigned int duration);
00269 
00270    /*! \brief Call a given phone number (address, etc), but don't
00271       take longer than timeout seconds to do so.  */
00272    int (* const call)(struct ast_channel *chan, char *addr, int timeout);
00273 
00274    /*! \brief Hangup (and possibly destroy) the channel */
00275    int (* const hangup)(struct ast_channel *chan);
00276 
00277    /*! \brief Answer the channel */
00278    int (* const answer)(struct ast_channel *chan);
00279 
00280    /*! \brief Read a frame, in standard format (see frame.h) */
00281    struct ast_frame * (* const read)(struct ast_channel *chan);
00282 
00283    /*! \brief Write a frame, in standard format (see frame.h) */
00284    int (* const write)(struct ast_channel *chan, struct ast_frame *frame);
00285 
00286    /*! \brief Display or transmit text */
00287    int (* const send_text)(struct ast_channel *chan, const char *text);
00288 
00289    /*! \brief Display or send an image */
00290    int (* const send_image)(struct ast_channel *chan, struct ast_frame *frame);
00291 
00292    /*! \brief Send HTML data */
00293    int (* const send_html)(struct ast_channel *chan, int subclass, const char *data, int len);
00294 
00295    /*! \brief Handle an exception, reading a frame */
00296    struct ast_frame * (* const exception)(struct ast_channel *chan);
00297 
00298    /*! \brief Bridge two channels of the same type together */
00299    enum ast_bridge_result (* const bridge)(struct ast_channel *c0, struct ast_channel *c1, int flags,
00300                   struct ast_frame **fo, struct ast_channel **rc, int timeoutms);
00301 
00302    /*! \brief Bridge two channels of the same type together (early) */
00303    enum ast_bridge_result (* const early_bridge)(struct ast_channel *c0, struct ast_channel *c1);
00304 
00305    /*! \brief Indicate a particular condition (e.g. AST_CONTROL_BUSY or AST_CONTROL_RINGING or AST_CONTROL_CONGESTION */
00306    int (* const indicate)(struct ast_channel *c, int condition, const void *data, size_t datalen);
00307 
00308    /*! \brief Fix up a channel:  If a channel is consumed, this is called.  Basically update any ->owner links */
00309    int (* const fixup)(struct ast_channel *oldchan, struct ast_channel *newchan);
00310 
00311    /*! \brief Set a given option */
00312    int (* const setoption)(struct ast_channel *chan, int option, void *data, int datalen);
00313 
00314    /*! \brief Query a given option */
00315    int (* const queryoption)(struct ast_channel *chan, int option, void *data, int *datalen);
00316 
00317    /*! \brief Blind transfer other side (see app_transfer.c and ast_transfer() */
00318    int (* const transfer)(struct ast_channel *chan, const char *newdest);
00319 
00320    /*! \brief Write a frame, in standard format */
00321    int (* const write_video)(struct ast_channel *chan, struct ast_frame *frame);
00322 
00323    /*! \brief Write a text frame, in standard format */
00324    int (* const write_text)(struct ast_channel *chan, struct ast_frame *frame);
00325 
00326    /*! \brief Find bridged channel */
00327    struct ast_channel *(* const bridged_channel)(struct ast_channel *chan, struct ast_channel *bridge);
00328 
00329    /*! \brief Provide additional read items for CHANNEL() dialplan function */
00330    int (* func_channel_read)(struct ast_channel *chan, const char *function, char *data, char *buf, size_t len);
00331 
00332    /*! \brief Provide additional write items for CHANNEL() dialplan function */
00333    int (* func_channel_write)(struct ast_channel *chan, const char *function, char *data, const char *value);
00334 
00335    /*! \brief Retrieve base channel (agent and local) */
00336    struct ast_channel* (* get_base_channel)(struct ast_channel *chan);
00337 
00338    /*! \brief Set base channel (agent and local) */
00339    int (* set_base_channel)(struct ast_channel *chan, struct ast_channel *base);
00340 
00341    /*! \brief Get the unique identifier for the PVT, i.e. SIP call-ID for SIP */
00342    const char * (* get_pvt_uniqueid)(struct ast_channel *chan);
00343 };
00344 
00345 struct ast_epoll_data;
00346 
00347 /*!
00348  * The high bit of the frame count is used as a debug marker, so
00349  * increments of the counters must be done with care.
00350  * Please use c->fin = FRAMECOUNT_INC(c->fin) and the same for c->fout.
00351  */
00352 #define  DEBUGCHAN_FLAG  0x80000000
00353 
00354 /* XXX not ideal to evaluate x twice... */
00355 #define  FRAMECOUNT_INC(x) ( ((x) & DEBUGCHAN_FLAG) | (((x)+1) & ~DEBUGCHAN_FLAG) )
00356 
00357 /*!
00358  * The current value of the debug flags is stored in the two
00359  * variables global_fin and global_fout (declared in main/channel.c)
00360  */
00361 extern unsigned long global_fin, global_fout;
00362 
00363 enum ast_channel_adsicpe {
00364    AST_ADSI_UNKNOWN,
00365    AST_ADSI_AVAILABLE,
00366    AST_ADSI_UNAVAILABLE,
00367    AST_ADSI_OFFHOOKONLY,
00368 };
00369 
00370 /*!
00371  * \brief ast_channel states
00372  *
00373  * \note Bits 0-15 of state are reserved for the state (up/down) of the line
00374  *       Bits 16-32 of state are reserved for flags
00375  */
00376 enum ast_channel_state {
00377    AST_STATE_DOWN,         /*!< Channel is down and available */
00378    AST_STATE_RESERVED,     /*!< Channel is down, but reserved */
00379    AST_STATE_OFFHOOK,      /*!< Channel is off hook */
00380    AST_STATE_DIALING,      /*!< Digits (or equivalent) have been dialed */
00381    AST_STATE_RING,         /*!< Line is ringing */
00382    AST_STATE_RINGING,      /*!< Remote end is ringing */
00383    AST_STATE_UP,        /*!< Line is up */
00384    AST_STATE_BUSY,         /*!< Line is busy */
00385    AST_STATE_DIALING_OFFHOOK, /*!< Digits (or equivalent) have been dialed while offhook */
00386    AST_STATE_PRERING,      /*!< Channel has detected an incoming call and is waiting for ring */
00387 
00388    AST_STATE_MUTE = (1 << 16),   /*!< Do not transmit voice data */
00389 };
00390 
00391 /*!
00392  * \brief Possible T38 states on channels
00393  */
00394 enum ast_t38_state {
00395    T38_STATE_UNAVAILABLE,  /*!< T38 is unavailable on this channel or disabled by configuration */
00396    T38_STATE_UNKNOWN,   /*!< The channel supports T38 but the current status is unknown */
00397    T38_STATE_NEGOTIATING,  /*!< T38 is being negotiated */
00398    T38_STATE_REJECTED,  /*!< Remote side has rejected our offer */
00399    T38_STATE_NEGOTIATED,   /*!< T38 established */
00400 };
00401 
00402 /*! \brief Main Channel structure associated with a channel.
00403  * This is the side of it mostly used by the pbx and call management.
00404  *
00405  * \note XXX It is important to remember to increment .cleancount each time
00406  *       this structure is changed. XXX
00407  *
00408  * \note When adding fields to this structure, it is important to add the field
00409  *       'in position' with like-aligned fields, so as to keep the compiler from
00410  *       having to add padding to align fields. The structure's fields are sorted
00411  *       in this order: pointers, structures, long, int/enum, short, char. This
00412  *       is especially important on 64-bit architectures, where mixing 4-byte
00413  *       and 8-byte fields causes 4 bytes of padding to be added before many
00414  *       8-byte fields.
00415  */
00416 
00417 struct ast_channel {
00418    const struct ast_channel_tech *tech;      /*!< Technology (point to channel driver) */
00419    void *tech_pvt;               /*!< Private data used by the technology driver */
00420    void *music_state;            /*!< Music State*/
00421    void *generatordata;          /*!< Current generator data if there is any */
00422    struct ast_generator *generator;    /*!< Current active data generator */
00423    struct ast_channel *_bridge;        /*!< Who are we bridged to, if we're bridged.
00424                           Who is proxying for us, if we are proxied (i.e. chan_agent).
00425                           Do not access directly, use ast_bridged_channel(chan) */
00426    struct ast_channel *masq;        /*!< Channel that will masquerade as us */
00427    struct ast_channel *masqr;       /*!< Who we are masquerading as */
00428    const char *blockproc;           /*!< Procedure causing blocking */
00429    const char *appl;          /*!< Current application */
00430    const char *data;          /*!< Data passed to current application */
00431    struct sched_context *sched;        /*!< Schedule context */
00432    struct ast_filestream *stream;         /*!< Stream itself. */
00433    struct ast_filestream *vstream;        /*!< Video Stream itself. */
00434    int (*timingfunc)(const void *data);
00435    void *timingdata;
00436    struct ast_pbx *pbx;          /*!< PBX private structure for this channel */
00437    struct ast_trans_pvt *writetrans;      /*!< Write translation path */
00438    struct ast_trans_pvt *readtrans;    /*!< Read translation path */
00439    struct ast_audiohook_list *audiohooks;
00440    struct ast_cdr *cdr;          /*!< Call Detail Record */
00441    struct ast_tone_zone *zone;         /*!< Tone zone as set in indications.conf or
00442                           in the CHANNEL dialplan function */
00443    struct ast_channel_monitor *monitor;      /*!< Channel monitoring */
00444 #ifdef HAVE_EPOLL
00445    struct ast_epoll_data *epfd_data[AST_MAX_FDS];
00446 #endif
00447 
00448    AST_DECLARE_STRING_FIELDS(
00449       AST_STRING_FIELD(name);       /*!< ASCII unique channel name */
00450       AST_STRING_FIELD(language);      /*!< Language requested for voice prompts */
00451       AST_STRING_FIELD(musicclass);    /*!< Default music class */
00452       AST_STRING_FIELD(accountcode);      /*!< Account code for billing */
00453       AST_STRING_FIELD(call_forward);     /*!< Where to forward to if asked to dial on this interface */
00454       AST_STRING_FIELD(uniqueid);      /*!< Unique Channel Identifier */
00455       AST_STRING_FIELD(parkinglot);    /*! Default parking lot, if empty, default parking lot  */
00456       AST_STRING_FIELD(dialcontext);      /*!< Dial: Extension context that we were called from */
00457    );
00458 
00459    struct timeval whentohangup;              /*!< Non-zero, set to actual time when channel is to be hung up */
00460    pthread_t blocker;            /*!< If anyone is blocking, this is them */
00461    ast_mutex_t lock_dont_use;       /*!< Lock a channel for some operations. See ast_channel_lock() */
00462    struct ast_callerid cid;         /*!< Caller ID, name, presentation etc */
00463    struct ast_frame dtmff;          /*!< DTMF frame */
00464    struct varshead varshead;        /*!< A linked list for channel variables. See \ref AstChanVar */
00465    ast_group_t callgroup;           /*!< Call group for call pickups */
00466    ast_group_t pickupgroup;         /*!< Pickup group - which calls groups can be picked up? */
00467    AST_LIST_HEAD_NOLOCK(, ast_frame) readq;
00468    AST_LIST_ENTRY(ast_channel) chan_list;    /*!< For easy linking */
00469    struct ast_jb jb;          /*!< The jitterbuffer state */
00470    struct timeval dtmf_tv;          /*!< The time that an in process digit began, or the last digit ended */
00471    AST_LIST_HEAD_NOLOCK(datastores, ast_datastore) datastores; /*!< Data stores on the channel */
00472 
00473    unsigned long insmpl;            /*!< Track the read/written samples for monitor use */
00474    unsigned long outsmpl;           /*!< Track the read/written samples for monitor use */
00475 
00476    int fds[AST_MAX_FDS];            /*!< File descriptors for channel -- Drivers will poll on
00477                           these file descriptors, so at least one must be non -1.
00478                           See \arg \ref AstFileDesc */
00479    int cdrflags;              /*!< Call Detail Record Flags */
00480    int _softhangup;           /*!< Whether or not we have been hung up...  Do not set this value
00481                           directly, use ast_softhangup() */
00482    int fdno;               /*!< Which fd had an event detected on */
00483    int streamid;              /*!< For streaming playback, the schedule ID */
00484    int vstreamid;             /*!< For streaming video playback, the schedule ID */
00485    int oldwriteformat;           /*!< Original writer format */
00486    int timingfd;              /*!< Timing fd */
00487    enum ast_channel_state _state;         /*!< State of line -- Don't write directly, use ast_setstate() */
00488    int rings;              /*!< Number of rings so far */
00489    int priority;              /*!< Dialplan: Current extension priority */
00490    int macropriority;            /*!< Macro: Current non-macro priority. See app_macro.c */
00491    int amaflags;              /*!< Set BEFORE PBX is started to determine AMA flags */
00492    enum ast_channel_adsicpe adsicpe;      /*!< Whether or not ADSI is detected on CPE */
00493    unsigned int fin;          /*!< Frames in counters. The high bit is a debug mask, so
00494                           the counter is only in the remaining bits */
00495    unsigned int fout;            /*!< Frames out counters. The high bit is a debug mask, so
00496                           the counter is only in the remaining bits */
00497    int hangupcause;           /*!< Why is the channel hanged up. See causes.h */
00498    unsigned int flags;           /*!< channel flags of AST_FLAG_ type */
00499    int alertpipe[2];
00500    int nativeformats;            /*!< Kinds of data this channel can natively handle */
00501    int readformat;               /*!< Requested read format */
00502    int writeformat;           /*!< Requested write format */
00503    int rawreadformat;            /*!< Raw read format */
00504    int rawwriteformat;           /*!< Raw write format */
00505    unsigned int emulate_dtmf_duration;    /*!< Number of ms left to emulate DTMF for */
00506 #ifdef HAVE_EPOLL
00507    int epfd;
00508 #endif
00509    int visible_indication;                         /*!< Indication currently playing on the channel */
00510 
00511    unsigned short transfercapability;     /*!< ISDN Transfer Capbility - AST_FLAG_DIGITAL is not enough */
00512 
00513    union {
00514       char unused_old_dtmfq[AST_MAX_EXTENSION];       /*!< (deprecated, use readq instead) Any/all queued DTMF characters */
00515       struct {
00516          struct ast_bridge *bridge;                                      /*!< Bridge this channel is participating in */
00517          struct ast_timer *timer;               /*!< timer object that provided timingfd */
00518       };
00519    };
00520 
00521    char context[AST_MAX_CONTEXT];         /*!< Dialplan: Current extension context */
00522    char exten[AST_MAX_EXTENSION];         /*!< Dialplan: Current extension number */
00523    char macrocontext[AST_MAX_CONTEXT];    /*!< Macro: Current non-macro context. See app_macro.c */
00524    char macroexten[AST_MAX_EXTENSION];    /*!< Macro: Current non-macro extension. See app_macro.c */
00525    char emulate_dtmf_digit;         /*!< Digit being emulated */
00526 };
00527 
00528 /*! \brief ast_channel_tech Properties */
00529 enum {
00530    /*! \brief Channels have this property if they can accept input with jitter;
00531     *         i.e. most VoIP channels */
00532    AST_CHAN_TP_WANTSJITTER = (1 << 0),
00533    /*! \brief Channels have this property if they can create jitter;
00534     *         i.e. most VoIP channels */
00535    AST_CHAN_TP_CREATESJITTER = (1 << 1),
00536 };
00537 
00538 /*! \brief ast_channel flags */
00539 enum {
00540    /*! Queue incoming dtmf, to be released when this flag is turned off */
00541    AST_FLAG_DEFER_DTMF =    (1 << 1),
00542    /*! write should be interrupt generator */
00543    AST_FLAG_WRITE_INT =     (1 << 2),
00544    /*! a thread is blocking on this channel */
00545    AST_FLAG_BLOCKING =      (1 << 3),
00546    /*! This is a zombie channel */
00547    AST_FLAG_ZOMBIE =        (1 << 4),
00548    /*! There is an exception pending */
00549    AST_FLAG_EXCEPTION =     (1 << 5),
00550    /*! Listening to moh XXX anthm promises me this will disappear XXX */
00551    AST_FLAG_MOH =           (1 << 6),
00552    /*! This channel is spying on another channel */
00553    AST_FLAG_SPYING =        (1 << 7),
00554    /*! This channel is in a native bridge */
00555    AST_FLAG_NBRIDGE =       (1 << 8),
00556    /*! the channel is in an auto-incrementing dialplan processor,
00557     *  so when ->priority is set, it will get incremented before
00558     *  finding the next priority to run */
00559    AST_FLAG_IN_AUTOLOOP =   (1 << 9),
00560    /*! This is an outgoing call */
00561    AST_FLAG_OUTGOING =      (1 << 10),
00562    /*! A DTMF_BEGIN frame has been read from this channel, but not yet an END */
00563    AST_FLAG_IN_DTMF =       (1 << 12),
00564    /*! A DTMF_END was received when not IN_DTMF, so the length of the digit is
00565     *  currently being emulated */
00566    AST_FLAG_EMULATE_DTMF =  (1 << 13),
00567    /*! This is set to tell the channel not to generate DTMF begin frames, and
00568     *  to instead only generate END frames. */
00569    AST_FLAG_END_DTMF_ONLY = (1 << 14),
00570    /*! Flag to show channels that this call is hangup due to the fact that the call
00571        was indeed anwered, but in another channel */
00572    AST_FLAG_ANSWERED_ELSEWHERE = (1 << 15),
00573    /*! This flag indicates that on a masquerade, an active stream should not
00574     *  be carried over */
00575    AST_FLAG_MASQ_NOSTREAM = (1 << 16),
00576    /*! This flag indicates that the hangup exten was run when the bridge terminated,
00577     *  a message aimed at preventing a subsequent hangup exten being run at the pbx_run
00578     *  level */
00579    AST_FLAG_BRIDGE_HANGUP_RUN = (1 << 17),
00580    /*! This flag indicates that the hangup exten should NOT be run when the
00581     *  bridge terminates, this will allow the hangup in the pbx loop to be run instead.
00582     *  */
00583    AST_FLAG_BRIDGE_HANGUP_DONT = (1 << 18),
00584    /*! This flag indicates whether the channel is in the channel list or not. */
00585    AST_FLAG_IN_CHANNEL_LIST = (1 << 19),
00586    /*! Disable certain workarounds.  This reintroduces certain bugs, but allows
00587     *  some non-traditional dialplans (like AGI) to continue to function.
00588     */
00589    AST_FLAG_DISABLE_WORKAROUNDS = (1 << 20),
00590 };
00591 
00592 /*! \brief ast_bridge_config flags */
00593 enum {
00594    AST_FEATURE_PLAY_WARNING = (1 << 0),
00595    AST_FEATURE_REDIRECT =     (1 << 1),
00596    AST_FEATURE_DISCONNECT =   (1 << 2),
00597    AST_FEATURE_ATXFER =       (1 << 3),
00598    AST_FEATURE_AUTOMON =      (1 << 4),
00599    AST_FEATURE_PARKCALL =     (1 << 5),
00600    AST_FEATURE_AUTOMIXMON =   (1 << 6),
00601    AST_FEATURE_NO_H_EXTEN =   (1 << 7),
00602    AST_FEATURE_WARNING_ACTIVE = (1 << 8),
00603 };
00604 
00605 /*! \brief bridge configuration */
00606 struct ast_bridge_config {
00607    struct ast_flags features_caller;
00608    struct ast_flags features_callee;
00609    struct timeval start_time;
00610    struct timeval nexteventts;
00611    struct timeval partialfeature_timer;
00612    long feature_timer;
00613    long timelimit;
00614    long play_warning;
00615    long warning_freq;
00616    const char *warning_sound;
00617    const char *end_sound;
00618    const char *start_sound;
00619    int firstpass;
00620    unsigned int flags;
00621    void (* end_bridge_callback)(void *);   /*!< A callback that is called after a bridge attempt */
00622    void *end_bridge_callback_data;         /*!< Data passed to the callback */
00623    /*! If the end_bridge_callback_data refers to a channel which no longer is going to
00624     * exist when the end_bridge_callback is called, then it needs to be fixed up properly
00625     */
00626    void (*end_bridge_callback_data_fixup)(struct ast_bridge_config *bconfig, struct ast_channel *originator, struct ast_channel *terminator);
00627 };
00628 
00629 struct chanmon;
00630 
00631 struct outgoing_helper {
00632    const char *context;
00633    const char *exten;
00634    int priority;
00635    const char *cid_num;
00636    const char *cid_name;
00637    const char *account;
00638    struct ast_variable *vars;
00639    struct ast_channel *parent_channel;
00640 };
00641 
00642 enum {
00643    AST_CDR_TRANSFER =   (1 << 0),
00644    AST_CDR_FORWARD =    (1 << 1),
00645    AST_CDR_CALLWAIT =   (1 << 2),
00646    AST_CDR_CONFERENCE = (1 << 3),
00647 };
00648 
00649 enum {
00650    /*!
00651     * Soft hangup requested by device or other internal reason.
00652     * Actual hangup needed.
00653     */
00654    AST_SOFTHANGUP_DEV =       (1 << 0),
00655    /*!
00656     * Used to break the normal frame flow so an async goto can be
00657     * done instead of actually hanging up.
00658     */
00659    AST_SOFTHANGUP_ASYNCGOTO = (1 << 1),
00660    /*!
00661     * Soft hangup requested by system shutdown.  Actual hangup
00662     * needed.
00663     */
00664    AST_SOFTHANGUP_SHUTDOWN =  (1 << 2),
00665    /*!
00666     * Used to break the normal frame flow after a timeout so an
00667     * implicit async goto can be done to the 'T' exten if it exists
00668     * instead of actually hanging up.  If the exten does not exist
00669     * then actually hangup.
00670     */
00671    AST_SOFTHANGUP_TIMEOUT =   (1 << 3),
00672    /*!
00673     * Soft hangup requested by application/channel-driver being
00674     * unloaded.  Actual hangup needed.
00675     */
00676    AST_SOFTHANGUP_APPUNLOAD = (1 << 4),
00677    /*!
00678     * Soft hangup requested by non-associated party.  Actual hangup
00679     * needed.
00680     */
00681    AST_SOFTHANGUP_EXPLICIT =  (1 << 5),
00682    /*!
00683     * Used to break a bridge so the channel can be spied upon
00684     * instead of actually hanging up.
00685     */
00686    AST_SOFTHANGUP_UNBRIDGE =  (1 << 6),
00687 
00688 
00689    /*!
00690     * \brief All softhangup flags.
00691     *
00692     * This can be used as an argument to ast_channel_softhangup_clear
00693     * to clear all softhangup flags from a channel.
00694     */
00695    AST_SOFTHANGUP_ALL =       (0xFFFFFFFF)
00696 };
00697 
00698 
00699 /*! \brief Channel reload reasons for manager events at load or reload of configuration */
00700 enum channelreloadreason {
00701    CHANNEL_MODULE_LOAD,
00702    CHANNEL_MODULE_RELOAD,
00703    CHANNEL_CLI_RELOAD,
00704    CHANNEL_MANAGER_RELOAD,
00705 };
00706 
00707 /*!
00708  * \note None of the datastore API calls lock the ast_channel they are using.
00709  *       So, the channel should be locked before calling the functions that
00710  *       take a channel argument.
00711  */
00712 
00713 /*!
00714  * \brief Create a channel data store object
00715  * \deprecated You should use the ast_datastore_alloc() generic function instead.
00716  * \version 1.6.1 deprecated
00717  */
00718 struct ast_datastore * attribute_malloc ast_channel_datastore_alloc(const struct ast_datastore_info *info, const char *uid)
00719    __attribute__((deprecated));
00720 
00721 /*!
00722  * \brief Free a channel data store object
00723  * \deprecated You should use the ast_datastore_free() generic function instead.
00724  * \version 1.6.1 deprecated
00725  */
00726 int ast_channel_datastore_free(struct ast_datastore *datastore)
00727    __attribute__((deprecated));
00728 
00729 /*! \brief Inherit datastores from a parent to a child. */
00730 int ast_channel_datastore_inherit(struct ast_channel *from, struct ast_channel *to);
00731 
00732 /*!
00733  * \brief Add a datastore to a channel
00734  *
00735  * \note The channel should be locked before calling this function.
00736  *
00737  * \retval 0 success
00738  * \retval non-zero failure
00739  */
00740 
00741 int ast_channel_datastore_add(struct ast_channel *chan, struct ast_datastore *datastore);
00742 
00743 /*!
00744  * \brief Remove a datastore from a channel
00745  *
00746  * \note The channel should be locked before calling this function.
00747  *
00748  * \retval 0 success
00749  * \retval non-zero failure
00750  */
00751 int ast_channel_datastore_remove(struct ast_channel *chan, struct ast_datastore *datastore);
00752 
00753 /*!
00754  * \brief Find a datastore on a channel
00755  *
00756  * \note The channel should be locked before calling this function.
00757  *
00758  * \note The datastore returned from this function must not be used if the
00759  *       reference to the channel is released.
00760  *
00761  * \retval pointer to the datastore if found
00762  * \retval NULL if not found
00763  */
00764 struct ast_datastore *ast_channel_datastore_find(struct ast_channel *chan, const struct ast_datastore_info *info, const char *uid);
00765 
00766 /*! \brief Change the state of a channel */
00767 int ast_setstate(struct ast_channel *chan, enum ast_channel_state);
00768 
00769 /*!
00770  * \brief Create a channel structure
00771  *
00772  * \retval NULL failure
00773  * \retval non-NULL successfully allocated channel
00774  *
00775  * \note By default, new channels are set to the "s" extension
00776  *       and "default" context.
00777  */
00778 struct ast_channel * attribute_malloc __attribute__((format(printf, 12, 13)))
00779    __ast_channel_alloc(int needqueue, int state, const char *cid_num,
00780              const char *cid_name, const char *acctcode,
00781              const char *exten, const char *context,
00782              const int amaflag, const char *file, int line,
00783              const char *function, const char *name_fmt, ...);
00784 
00785 #define ast_channel_alloc(needqueue, state, cid_num, cid_name, acctcode, exten, context, amaflag, ...) \
00786    __ast_channel_alloc(needqueue, state, cid_num, cid_name, acctcode, exten, context, amaflag, \
00787              __FILE__, __LINE__, __FUNCTION__, __VA_ARGS__)
00788 
00789 /*!
00790  * \brief Queue one or more frames to a channel's frame queue
00791  *
00792  * \param chan the channel to queue the frame(s) on
00793  * \param f the frame(s) to queue.  Note that the frame(s) will be duplicated
00794  *        by this function.  It is the responsibility of the caller to handle
00795  *        freeing the memory associated with the frame(s) being passed if
00796  *        necessary.
00797  *
00798  * \retval 0 success
00799  * \retval non-zero failure
00800  */
00801 int ast_queue_frame(struct ast_channel *chan, struct ast_frame *f);
00802 
00803 /*!
00804  * \brief Queue one or more frames to the head of a channel's frame queue
00805  *
00806  * \param chan the channel to queue the frame(s) on
00807  * \param f the frame(s) to queue.  Note that the frame(s) will be duplicated
00808  *        by this function.  It is the responsibility of the caller to handle
00809  *        freeing the memory associated with the frame(s) being passed if
00810  *        necessary.
00811  *
00812  * \retval 0 success
00813  * \retval non-zero failure
00814  */
00815 int ast_queue_frame_head(struct ast_channel *chan, struct ast_frame *f);
00816 
00817 /*!
00818  * \brief Queue a hangup frame
00819  *
00820  * \note The channel does not need to be locked before calling this function.
00821  */
00822 int ast_queue_hangup(struct ast_channel *chan);
00823 
00824 /*!
00825  * \brief Queue a hangup frame with hangupcause set
00826  *
00827  * \note The channel does not need to be locked before calling this function.
00828  * \param[in] chan channel to queue frame onto
00829  * \param[in] cause the hangup cause
00830  * \return 0 on success, -1 on error
00831  * \since 1.6.1
00832  */
00833 int ast_queue_hangup_with_cause(struct ast_channel *chan, int cause);
00834 
00835 /*!
00836  * \brief Queue a control frame with payload
00837  *
00838  * \param chan channel to queue frame onto
00839  * \param control type of control frame
00840  *
00841  * \note The channel does not need to be locked before calling this function.
00842  *
00843  * \retval zero on success
00844  * \retval non-zero on failure
00845  */
00846 int ast_queue_control(struct ast_channel *chan, enum ast_control_frame_type control);
00847 
00848 /*!
00849  * \brief Queue a control frame with payload
00850  *
00851  * \param chan channel to queue frame onto
00852  * \param control type of control frame
00853  * \param data pointer to payload data to be included in frame
00854  * \param datalen number of bytes of payload data
00855  *
00856  * \retval 0 success
00857  * \retval non-zero failure
00858  *
00859  * The supplied payload data is copied into the frame, so the caller's copy
00860  * is not modified nor freed, and the resulting frame will retain a copy of
00861  * the data even if the caller frees their local copy.
00862  *
00863  * \note This method should be treated as a 'network transport'; in other
00864  * words, your frames may be transferred across an IAX2 channel to another
00865  * system, which may be a different endianness than yours. Because of this,
00866  * you should ensure that either your frames will never be expected to work
00867  * across systems, or that you always put your payload data into 'network byte
00868  * order' before calling this function.
00869  *
00870  * \note The channel does not need to be locked before calling this function.
00871  */
00872 int ast_queue_control_data(struct ast_channel *chan, enum ast_control_frame_type control,
00873             const void *data, size_t datalen);
00874 
00875 /*!
00876  * \brief Change channel name
00877  *
00878  * \note The channel must be locked before calling this function.
00879  */
00880 void ast_change_name(struct ast_channel *chan, char *newname);
00881 
00882 /*! \brief Free a channel structure */
00883 void  ast_channel_free(struct ast_channel *);
00884 
00885 /*!
00886  * \brief Requests a channel
00887  *
00888  * \param type type of channel to request
00889  * \param format requested channel format (codec)
00890  * \param data data to pass to the channel requester
00891  * \param status status
00892  *
00893  * Request a channel of a given type, with data as optional information used
00894  * by the low level module
00895  *
00896  * \retval NULL failure
00897  * \retval non-NULL channel on success
00898  */
00899 struct ast_channel *ast_request(const char *type, int format, void *data, int *status);
00900 
00901 /*!
00902  * \brief Request a channel of a given type, with data as optional information used
00903  *        by the low level module and attempt to place a call on it
00904  *
00905  * \param type type of channel to request
00906  * \param format requested channel format
00907  * \param data data to pass to the channel requester
00908  * \param timeout maximum amount of time to wait for an answer
00909  * \param reason why unsuccessful (if unsuccessful)
00910  * \param cid_num Caller-ID Number
00911  * \param cid_name Caller-ID Name (ascii)
00912  *
00913  * \return Returns an ast_channel on success or no answer, NULL on failure.  Check the value of chan->_state
00914  * to know if the call was answered or not.
00915  */
00916 struct ast_channel *ast_request_and_dial(const char *type, int format, void *data,
00917    int timeout, int *reason, const char *cid_num, const char *cid_name);
00918 
00919 /*!
00920  * \brief Request a channel of a given type, with data as optional information used
00921  * by the low level module and attempt to place a call on it
00922  * \param type type of channel to request
00923  * \param format requested channel format
00924  * \param data data to pass to the channel requester
00925  * \param timeout maximum amount of time to wait for an answer
00926  * \param reason why unsuccessful (if unsuccessful)
00927  * \param cid_num Caller-ID Number
00928  * \param cid_name Caller-ID Name (ascii)
00929  * \param oh Outgoing helper
00930  * \return Returns an ast_channel on success or no answer, NULL on failure.  Check the value of chan->_state
00931  * to know if the call was answered or not.
00932  */
00933 struct ast_channel *__ast_request_and_dial(const char *type, int format, void *data,
00934    int timeout, int *reason, const char *cid_num, const char *cid_name, struct outgoing_helper *oh);
00935 /*!
00936 * \brief Forwards a call to a new channel specified by the original channel's call_forward str.  If possible, the new forwarded channel is created and returned while the original one is terminated.
00937 * \param caller in channel that requested orig
00938 * \param orig channel being replaced by the call forward channel
00939 * \param timeout maximum amount of time to wait for setup of new forward channel
00940 * \param format requested channel format
00941 * \param oh outgoing helper used with original channel
00942 * \param outstate reason why unsuccessful (if uncuccessful)
00943 * \return Returns the forwarded call's ast_channel on success or NULL on failure
00944 */
00945 struct ast_channel *ast_call_forward(struct ast_channel *caller, struct ast_channel *orig, int *timeout, int format, struct outgoing_helper *oh, int *outstate);
00946 
00947 /*!\brief Register a channel technology (a new channel driver)
00948  * Called by a channel module to register the kind of channels it supports.
00949  * \param tech Structure defining channel technology or "type"
00950  * \return Returns 0 on success, -1 on failure.
00951  */
00952 int ast_channel_register(const struct ast_channel_tech *tech);
00953 
00954 /*! \brief Unregister a channel technology
00955  * \param tech Structure defining channel technology or "type" that was previously registered
00956  * \return No return value.
00957  */
00958 void ast_channel_unregister(const struct ast_channel_tech *tech);
00959 
00960 /*! \brief Get a channel technology structure by name
00961  * \param name name of technology to find
00962  * \return a pointer to the structure, or NULL if no matching technology found
00963  */
00964 const struct ast_channel_tech *ast_get_channel_tech(const char *name);
00965 
00966 #ifdef CHANNEL_TRACE
00967 /*! \brief Update the context backtrace if tracing is enabled
00968  * \return Returns 0 on success, -1 on failure
00969  */
00970 int ast_channel_trace_update(struct ast_channel *chan);
00971 
00972 /*! \brief Enable context tracing in the channel
00973  * \return Returns 0 on success, -1 on failure
00974  */
00975 int ast_channel_trace_enable(struct ast_channel *chan);
00976 
00977 /*! \brief Disable context tracing in the channel.
00978  * \note Does not remove current trace entries
00979  * \return Returns 0 on success, -1 on failure
00980  */
00981 int ast_channel_trace_disable(struct ast_channel *chan);
00982 
00983 /*! \brief Whether or not context tracing is enabled
00984  * \return Returns -1 when the trace is enabled. 0 if not.
00985  */
00986 int ast_channel_trace_is_enabled(struct ast_channel *chan);
00987 
00988 /*! \brief Put the channel backtrace in a string
00989  * \return Returns the amount of lines in the backtrace. -1 on error.
00990  */
00991 int ast_channel_trace_serialize(struct ast_channel *chan, struct ast_str **out);
00992 #endif
00993 
00994 /*! \brief Hang up a channel
00995  * \note This function performs a hard hangup on a channel.  Unlike the soft-hangup, this function
00996  * performs all stream stopping, etc, on the channel that needs to end.
00997  * chan is no longer valid after this call.
00998  * \param chan channel to hang up
00999  * \return Returns 0 on success, -1 on failure.
01000  */
01001 int ast_hangup(struct ast_channel *chan);
01002 
01003 /*!
01004  * \brief Softly hangup up a channel
01005  *
01006  * \param chan channel to be soft-hung-up
01007  * \param reason an AST_SOFTHANGUP_* reason code
01008  *
01009  * Call the protocol layer, but don't destroy the channel structure
01010  * (use this if you are trying to
01011  * safely hangup a channel managed by another thread.
01012  *
01013  * \note The channel passed to this function does not need to be locked.
01014  *
01015  * \return Returns 0 regardless
01016  */
01017 int ast_softhangup(struct ast_channel *chan, int reason);
01018 
01019 /*! \brief Softly hangup up a channel (no channel lock)
01020  * \param chan channel to be soft-hung-up
01021  * \param reason an AST_SOFTHANGUP_* reason code
01022  */
01023 int ast_softhangup_nolock(struct ast_channel *chan, int reason);
01024 
01025 /*!
01026  * \brief Clear a set of softhangup flags from a channel
01027  *
01028  * Never clear a softhangup flag from a channel directly.  Instead,
01029  * use this function.  This ensures that all aspects of the softhangup
01030  * process are aborted.
01031  *
01032  * \param chan the channel to clear the flag on
01033  * \param flag the flag or flags to clear
01034  *
01035  * \return Nothing.
01036  */
01037 void ast_channel_clear_softhangup(struct ast_channel *chan, int flag);
01038 
01039 /*! \brief Check to see if a channel is needing hang up
01040  * \param chan channel on which to check for hang up
01041  * This function determines if the channel is being requested to be hung up.
01042  * \return Returns 0 if not, or 1 if hang up is requested (including time-out).
01043  */
01044 int ast_check_hangup(struct ast_channel *chan);
01045 
01046 /*!
01047  * \brief Compare a offset with the settings of when to hang a channel up
01048  * \param chan channel on which to check for hang up
01049  * \param offset offset in seconds from current time
01050  * \return 1, 0, or -1
01051  * This function compares a offset from current time with the absolute time
01052  * out on a channel (when to hang up). If the absolute time out on a channel
01053  * is earlier than current time plus the offset, it returns 1, if the two
01054  * time values are equal, it return 0, otherwise, it return -1.
01055  * \sa ast_channel_cmpwhentohangup_tv()
01056  * \version 1.6.1 deprecated function (only had seconds precision)
01057  */
01058 int ast_channel_cmpwhentohangup(struct ast_channel *chan, time_t offset) __attribute__((deprecated));
01059 
01060 /*!
01061  * \brief Compare a offset with the settings of when to hang a channel up
01062  * \param chan channel on which to check for hangup
01063  * \param offset offset in seconds and microseconds from current time
01064  * \return 1, 0, or -1
01065  * This function compares a offset from current time with the absolute time
01066  * out on a channel (when to hang up). If the absolute time out on a channel
01067  * is earlier than current time plus the offset, it returns 1, if the two
01068  * time values are equal, it return 0, otherwise, it return -1.
01069  * \since 1.6.1
01070  */
01071 int ast_channel_cmpwhentohangup_tv(struct ast_channel *chan, struct timeval offset);
01072 
01073 /*! \brief Set when to hang a channel up
01074  *
01075  * \param chan channel on which to check for hang up
01076  * \param offset offset in seconds relative to the current time of when to hang up
01077  *
01078  * This function sets the absolute time out on a channel (when to hang up).
01079  *
01080  * \note This function does not require that the channel is locked before
01081  *       calling it.
01082  *
01083  * \return Nothing
01084  * \sa ast_channel_setwhentohangup_tv()
01085  * \version 1.6.1 deprecated function (only had seconds precision)
01086  */
01087 void ast_channel_setwhentohangup(struct ast_channel *chan, time_t offset) __attribute__((deprecated));
01088 
01089 /*! \brief Set when to hang a channel up
01090  *
01091  * \param chan channel on which to check for hang up
01092  * \param offset offset in seconds and useconds relative to the current time of when to hang up
01093  *
01094  * This function sets the absolute time out on a channel (when to hang up).
01095  *
01096  * \note This function does not require that the channel is locked before
01097  * calling it.
01098  *
01099  * \return Nothing
01100  * \since 1.6.1
01101  */
01102 void ast_channel_setwhentohangup_tv(struct ast_channel *chan, struct timeval offset);
01103 
01104 /*!
01105  * \brief Answer a channel
01106  *
01107  * \param chan channel to answer
01108  *
01109  * This function answers a channel and handles all necessary call
01110  * setup functions.
01111  *
01112  * \note The channel passed does not need to be locked, but is locked
01113  * by the function when needed.
01114  *
01115  * \note This function will wait up to 500 milliseconds for media to
01116  * arrive on the channel before returning to the caller, so that the
01117  * caller can properly assume the channel is 'ready' for media flow.
01118  *
01119  * \retval 0 on success
01120  * \retval non-zero on failure
01121  */
01122 int ast_answer(struct ast_channel *chan);
01123 
01124 /*!
01125  * \brief Answer a channel
01126  *
01127  * \param chan channel to answer
01128  * \param cdr_answer flag to control whether any associated CDR should be marked as 'answered'
01129  *
01130  * This function answers a channel and handles all necessary call
01131  * setup functions.
01132  *
01133  * \note The channel passed does not need to be locked, but is locked
01134  * by the function when needed.
01135  *
01136  * \note Unlike ast_answer(), this function will not wait for media
01137  * flow to begin. The caller should be careful before sending media
01138  * to the channel before incoming media arrives, as the outgoing
01139  * media may be lost.
01140  *
01141  * \retval 0 on success
01142  * \retval non-zero on failure
01143  */
01144 int ast_raw_answer(struct ast_channel *chan, int cdr_answer);
01145 
01146 /*!
01147  * \brief Answer a channel, with a selectable delay before returning
01148  *
01149  * \param chan channel to answer
01150  * \param delay maximum amount of time to wait for incoming media
01151  * \param cdr_answer flag to control whether any associated CDR should be marked as 'answered'
01152  *
01153  * This function answers a channel and handles all necessary call
01154  * setup functions.
01155  *
01156  * \note The channel passed does not need to be locked, but is locked
01157  * by the function when needed.
01158  *
01159  * \note This function will wait up to 'delay' milliseconds for media to
01160  * arrive on the channel before returning to the caller, so that the
01161  * caller can properly assume the channel is 'ready' for media flow. If
01162  * 'delay' is less than 500, the function will wait up to 500 milliseconds.
01163  *
01164  * \retval 0 on success
01165  * \retval non-zero on failure
01166  */
01167 int __ast_answer(struct ast_channel *chan, unsigned int delay, int cdr_answer);
01168 
01169 /*! \brief Make a call
01170  * \param chan which channel to make the call on
01171  * \param addr destination of the call
01172  * \param timeout time to wait on for connect
01173  * Place a call, take no longer than timeout ms.
01174    \return Returns -1 on failure, 0 on not enough time
01175    (does not automatically stop ringing), and
01176    the number of seconds the connect took otherwise.
01177    */
01178 int ast_call(struct ast_channel *chan, char *addr, int timeout);
01179 
01180 /*! \brief Indicates condition of channel
01181  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
01182  * \param chan channel to change the indication
01183  * \param condition which condition to indicate on the channel
01184  * \return Returns 0 on success, -1 on failure
01185  */
01186 int ast_indicate(struct ast_channel *chan, int condition);
01187 
01188 /*! \brief Indicates condition of channel, with payload
01189  * \note Indicate a condition such as AST_CONTROL_HOLD with payload being music on hold class
01190  * \param chan channel to change the indication
01191  * \param condition which condition to indicate on the channel
01192  * \param data pointer to payload data
01193  * \param datalen size of payload data
01194  * \return Returns 0 on success, -1 on failure
01195  */
01196 int ast_indicate_data(struct ast_channel *chan, int condition, const void *data, size_t datalen);
01197 
01198 /* Misc stuff ------------------------------------------------ */
01199 
01200 /*! \brief Wait for input on a channel
01201  * \param chan channel to wait on
01202  * \param ms length of time to wait on the channel
01203  * Wait for input on a channel for a given # of milliseconds (<0 for indefinite).
01204   \return Returns < 0 on  failure, 0 if nothing ever arrived, and the # of ms remaining otherwise */
01205 int ast_waitfor(struct ast_channel *chan, int ms);
01206 
01207 /*!
01208  * \brief Should we keep this frame for later?
01209  *
01210  * There are functions such as ast_safe_sleep which will
01211  * service a channel to ensure that it does not have a
01212  * large backlog of queued frames. When this happens,
01213  * we want to hold on to specific frame types and just drop
01214  * others. This function will tell if the frame we just
01215  * read should be held onto.
01216  *
01217  * \param frame The frame we just read
01218  * \retval 1 frame should be kept
01219  * \retval 0 frame should be dropped
01220  */
01221 int ast_is_deferrable_frame(const struct ast_frame *frame);
01222 
01223 /*!
01224  * \brief Wait for a specified amount of time, looking for hangups
01225  * \param chan channel to wait for
01226  * \param ms length of time in milliseconds to sleep
01227  * Waits for a specified amount of time, servicing the channel as required.
01228  * \return returns -1 on hangup, otherwise 0.
01229  */
01230 int ast_safe_sleep(struct ast_channel *chan, int ms);
01231 
01232 /*! \brief Wait for a specified amount of time, looking for hangups and a condition argument
01233  * \param chan channel to wait for
01234  * \param ms length of time in milliseconds to sleep
01235  * \param cond a function pointer for testing continue condition
01236  * \param data argument to be passed to the condition test function
01237  * \return returns -1 on hangup, otherwise 0.
01238  * Waits for a specified amount of time, servicing the channel as required. If cond
01239  * returns 0, this function returns.
01240  */
01241 int ast_safe_sleep_conditional(struct ast_channel *chan, int ms, int (*cond)(void*), void *data );
01242 
01243 /*! \brief Waits for activity on a group of channels
01244  * \param chan an array of pointers to channels
01245  * \param n number of channels that are to be waited upon
01246  * \param fds an array of fds to wait upon
01247  * \param nfds the number of fds to wait upon
01248  * \param exception exception flag
01249  * \param outfd fd that had activity on it
01250  * \param ms how long the wait was
01251  * Big momma function here.  Wait for activity on any of the n channels, or any of the nfds
01252    file descriptors.
01253    \return Returns the channel with activity, or NULL on error or if an FD
01254    came first.  If the FD came first, it will be returned in outfd, otherwise, outfd
01255    will be -1 */
01256 struct ast_channel *ast_waitfor_nandfds(struct ast_channel **chan, int n,
01257    int *fds, int nfds, int *exception, int *outfd, int *ms);
01258 
01259 /*! \brief Waits for input on a group of channels
01260    Wait for input on an array of channels for a given # of milliseconds.
01261    \return Return channel with activity, or NULL if none has activity.
01262    \param chan an array of pointers to channels
01263    \param n number of channels that are to be waited upon
01264    \param ms time "ms" is modified in-place, if applicable */
01265 struct ast_channel *ast_waitfor_n(struct ast_channel **chan, int n, int *ms);
01266 
01267 /*! \brief Waits for input on an fd
01268    This version works on fd's only.  Be careful with it. */
01269 int ast_waitfor_n_fd(int *fds, int n, int *ms, int *exception);
01270 
01271 
01272 /*! \brief Reads a frame
01273  * \param chan channel to read a frame from
01274  * \return Returns a frame, or NULL on error.  If it returns NULL, you
01275    best just stop reading frames and assume the channel has been
01276    disconnected. */
01277 struct ast_frame *ast_read(struct ast_channel *chan);
01278 
01279 /*! \brief Reads a frame, returning AST_FRAME_NULL frame if audio.
01280    \param chan channel to read a frame from
01281    \return  Returns a frame, or NULL on error.  If it returns NULL, you
01282       best just stop reading frames and assume the channel has been
01283       disconnected.
01284    \note Audio is replaced with AST_FRAME_NULL to avoid
01285    transcode when the resulting audio is not necessary. */
01286 struct ast_frame *ast_read_noaudio(struct ast_channel *chan);
01287 
01288 /*! \brief Write a frame to a channel
01289  * This function writes the given frame to the indicated channel.
01290  * \param chan destination channel of the frame
01291  * \param frame frame that will be written
01292  * \return It returns 0 on success, -1 on failure.
01293  */
01294 int ast_write(struct ast_channel *chan, struct ast_frame *frame);
01295 
01296 /*! \brief Write video frame to a channel
01297  * This function writes the given frame to the indicated channel.
01298  * \param chan destination channel of the frame
01299  * \param frame frame that will be written
01300  * \return It returns 1 on success, 0 if not implemented, and -1 on failure.
01301  */
01302 int ast_write_video(struct ast_channel *chan, struct ast_frame *frame);
01303 
01304 /*! \brief Write text frame to a channel
01305  * This function writes the given frame to the indicated channel.
01306  * \param chan destination channel of the frame
01307  * \param frame frame that will be written
01308  * \return It returns 1 on success, 0 if not implemented, and -1 on failure.
01309  */
01310 int ast_write_text(struct ast_channel *chan, struct ast_frame *frame);
01311 
01312 /*! \brief Send empty audio to prime a channel driver */
01313 int ast_prod(struct ast_channel *chan);
01314 
01315 /*! \brief Sets read format on channel chan
01316  * Set read format for channel to whichever component of "format" is best.
01317  * \param chan channel to change
01318  * \param format format to change to
01319  * \return Returns 0 on success, -1 on failure
01320  */
01321 int ast_set_read_format(struct ast_channel *chan, int format);
01322 
01323 /*! \brief Sets write format on channel chan
01324  * Set write format for channel to whichever component of "format" is best.
01325  * \param chan channel to change
01326  * \param format new format for writing
01327  * \return Returns 0 on success, -1 on failure
01328  */
01329 int ast_set_write_format(struct ast_channel *chan, int format);
01330 
01331 /*!
01332  * \brief Sends text to a channel
01333  *
01334  * \param chan channel to act upon
01335  * \param text string of text to send on the channel
01336  *
01337  * Write text to a display on a channel
01338  *
01339  * \note The channel does not need to be locked before calling this function.
01340  *
01341  * \retval 0 on success
01342  * \retval -1 on failure
01343  */
01344 int ast_sendtext(struct ast_channel *chan, const char *text);
01345 
01346 /*! \brief Receives a text character from a channel
01347  * \param chan channel to act upon
01348  * \param timeout timeout in milliseconds (0 for infinite wait)
01349  * Read a char of text from a channel
01350  * Returns 0 on success, -1 on failure
01351  */
01352 int ast_recvchar(struct ast_channel *chan, int timeout);
01353 
01354 /*! \brief Send a DTMF digit to a channel
01355  * Send a DTMF digit to a channel.
01356  * \param chan channel to act upon
01357  * \param digit the DTMF digit to send, encoded in ASCII
01358  * \param duration the duration of the digit ending in ms
01359  * \return Returns 0 on success, -1 on failure
01360  */
01361 int ast_senddigit(struct ast_channel *chan, char digit, unsigned int duration);
01362 
01363 /*! \brief Send a DTMF digit to a channel
01364  * Send a DTMF digit to a channel.
01365  * \param chan channel to act upon
01366  * \param digit the DTMF digit to send, encoded in ASCII
01367  * \return Returns 0 on success, -1 on failure
01368  */
01369 int ast_senddigit_begin(struct ast_channel *chan, char digit);
01370 
01371 /*! \brief Send a DTMF digit to a channel
01372 
01373  * Send a DTMF digit to a channel.
01374  * \param chan channel to act upon
01375  * \param digit the DTMF digit to send, encoded in ASCII
01376  * \param duration the duration of the digit ending in ms
01377  * \return Returns 0 on success, -1 on failure
01378  */
01379 int ast_senddigit_end(struct ast_channel *chan, char digit, unsigned int duration);
01380 
01381 /*! \brief Receives a text string from a channel
01382  * Read a string of text from a channel
01383  * \param chan channel to act upon
01384  * \param timeout timeout in milliseconds (0 for infinite wait)
01385  * \return the received text, or NULL to signify failure.
01386  */
01387 char *ast_recvtext(struct ast_channel *chan, int timeout);
01388 
01389 /*! \brief Browse channels in use
01390  * Browse the channels currently in use
01391  * \param prev where you want to start in the channel list
01392  * \return Returns the next channel in the list, NULL on end.
01393  *    If it returns a channel, that channel *has been locked*!
01394  */
01395 struct ast_channel *ast_channel_walk_locked(const struct ast_channel *prev);
01396 
01397 /*! \brief Get channel by name or uniqueid (locks channel) */
01398 struct ast_channel *ast_get_channel_by_name_locked(const char *chan);
01399 
01400 /*! \brief Get channel by name or uniqueid prefix (locks channel) */
01401 struct ast_channel *ast_get_channel_by_name_prefix_locked(const char *name, const int namelen);
01402 
01403 /*! \brief Get channel by name or uniqueid prefix (locks channel) */
01404 struct ast_channel *ast_walk_channel_by_name_prefix_locked(const struct ast_channel *chan, const char *name, const int namelen);
01405 
01406 /*! \brief Get channel by exten (and optionally context) and lock it */
01407 struct ast_channel *ast_get_channel_by_exten_locked(const char *exten, const char *context);
01408 
01409 /*! \brief Get next channel by exten (and optionally context) and lock it */
01410 struct ast_channel *ast_walk_channel_by_exten_locked(const struct ast_channel *chan, const char *exten,
01411                        const char *context);
01412 
01413 /*! \brief Search for a channel based on the passed channel matching callback
01414  * Search for a channel based on the specified is_match callback, and return the
01415  * first channel that we match.  When returned, the channel will be locked.  Note
01416  * that the is_match callback is called with the passed channel locked, and should
01417  * return 0 if there is no match, and non-zero if there is.
01418  * \param is_match callback executed on each channel until non-zero is returned, or we
01419  *        run out of channels to search.
01420  * \param data data passed to the is_match callback during each invocation.
01421  * \return Returns the matched channel, or NULL if no channel was matched.
01422  */
01423 struct ast_channel *ast_channel_search_locked(int (*is_match)(struct ast_channel *, void *), void *data);
01424 
01425 /*! ! \brief Waits for a digit
01426  * \param c channel to wait for a digit on
01427  * \param ms how many milliseconds to wait
01428  * \return Returns <0 on error, 0 on no entry, and the digit on success. */
01429 int ast_waitfordigit(struct ast_channel *c, int ms);
01430 
01431 /*! \brief Wait for a digit
01432  Same as ast_waitfordigit() with audio fd for outputting read audio and ctrlfd to monitor for reading.
01433  * \param c channel to wait for a digit on
01434  * \param ms how many milliseconds to wait
01435  * \param audiofd audio file descriptor to write to if audio frames are received
01436  * \param ctrlfd control file descriptor to monitor for reading
01437  * \return Returns 1 if ctrlfd becomes available */
01438 int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int ctrlfd);
01439 
01440 /*! Reads multiple digits
01441  * \param c channel to read from
01442  * \param s string to read in to.  Must be at least the size of your length
01443  * \param len how many digits to read (maximum)
01444  * \param timeout how long to timeout between digits
01445  * \param rtimeout timeout to wait on the first digit
01446  * \param enders digits to end the string
01447  * Read in a digit string "s", max length "len", maximum timeout between
01448    digits "timeout" (-1 for none), terminated by anything in "enders".  Give them rtimeout
01449    for the first digit.  Returns 0 on normal return, or 1 on a timeout.  In the case of
01450    a timeout, any digits that were read before the timeout will still be available in s.
01451    RETURNS 2 in full version when ctrlfd is available, NOT 1*/
01452 int ast_readstring(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders);
01453 int ast_readstring_full(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders, int audiofd, int ctrlfd);
01454 
01455 /*! \brief Report DTMF on channel 0 */
01456 #define AST_BRIDGE_DTMF_CHANNEL_0      (1 << 0)
01457 /*! \brief Report DTMF on channel 1 */
01458 #define AST_BRIDGE_DTMF_CHANNEL_1      (1 << 1)
01459 /*! \brief Return all voice frames on channel 0 */
01460 #define AST_BRIDGE_REC_CHANNEL_0    (1 << 2)
01461 /*! \brief Return all voice frames on channel 1 */
01462 #define AST_BRIDGE_REC_CHANNEL_1    (1 << 3)
01463 /*! \brief Ignore all signal frames except NULL */
01464 #define AST_BRIDGE_IGNORE_SIGS         (1 << 4)
01465 
01466 
01467 /*! \brief Makes two channel formats compatible
01468  * \param c0 first channel to make compatible
01469  * \param c1 other channel to make compatible
01470  * Set two channels to compatible formats -- call before ast_channel_bridge in general .
01471  * \return Returns 0 on success and -1 if it could not be done */
01472 int ast_channel_make_compatible(struct ast_channel *c0, struct ast_channel *c1);
01473 
01474 /*! Bridge two channels together (early)
01475  * \param c0 first channel to bridge
01476  * \param c1 second channel to bridge
01477  * Bridge two channels (c0 and c1) together early. This implies either side may not be answered yet.
01478  * \return Returns 0 on success and -1 if it could not be done */
01479 int ast_channel_early_bridge(struct ast_channel *c0, struct ast_channel *c1);
01480 
01481 /*! Bridge two channels together
01482  * \param c0 first channel to bridge
01483  * \param c1 second channel to bridge
01484  * \param config config for the channels
01485  * \param fo destination frame(?)
01486  * \param rc destination channel(?)
01487  * Bridge two channels (c0 and c1) together.  If an important frame occurs, we return that frame in
01488    *rf (remember, it could be NULL) and which channel (0 or 1) in rc */
01489 /* int ast_channel_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc); */
01490 int ast_channel_bridge(struct ast_channel *c0,struct ast_channel *c1,
01491    struct ast_bridge_config *config, struct ast_frame **fo, struct ast_channel **rc);
01492 
01493 /*!
01494  * \brief Weird function made for call transfers
01495  *
01496  * \param original channel to make a copy of
01497  * \param clone copy of the original channel
01498  *
01499  * This is a very strange and freaky function used primarily for transfer.  Suppose that
01500  * "original" and "clone" are two channels in random situations.  This function takes
01501  * the guts out of "clone" and puts them into the "original" channel, then alerts the
01502  * channel driver of the change, asking it to fixup any private information (like the
01503  * p->owner pointer) that is affected by the change.  The physical layer of the original
01504  * channel is hung up.
01505  *
01506  * \note Neither channel passed here needs to be locked before calling this function.
01507  */
01508 int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clone);
01509 
01510 /*! Gives the string form of a given cause code */
01511 /*!
01512  * \param state cause to get the description of
01513  * Give a name to a cause code
01514  * Returns the text form of the binary cause code given
01515  */
01516 const char *ast_cause2str(int state) attribute_pure;
01517 
01518 /*! Convert the string form of a cause code to a number */
01519 /*!
01520  * \param name string form of the cause
01521  * Returns the cause code
01522  */
01523 int ast_str2cause(const char *name) attribute_pure;
01524 
01525 /*! Gives the string form of a given channel state */
01526 /*!
01527  * \param ast_channel_state state to get the name of
01528  * Give a name to a state
01529  * Returns the text form of the binary state given
01530  */
01531 const char *ast_state2str(enum ast_channel_state);
01532 
01533 /*! Gives the string form of a given transfer capability */
01534 /*!
01535  * \param transfercapability transfercapabilty to get the name of
01536  * Give a name to a transfercapbility
01537  * See above
01538  * Returns the text form of the binary transfer capability
01539  */
01540 char *ast_transfercapability2str(int transfercapability) attribute_const;
01541 
01542 /* Options: Some low-level drivers may implement "options" allowing fine tuning of the
01543    low level channel.  See frame.h for options.  Note that many channel drivers may support
01544    none or a subset of those features, and you should not count on this if you want your
01545    asterisk application to be portable.  They're mainly useful for tweaking performance */
01546 
01547 /*! Sets an option on a channel */
01548 /*!
01549  * \param channel channel to set options on
01550  * \param option option to change
01551  * \param data data specific to option
01552  * \param datalen length of the data
01553  * \param block blocking or not
01554  * Set an option on a channel (see frame.h), optionally blocking awaiting the reply
01555  * Returns 0 on success and -1 on failure
01556  */
01557 int ast_channel_setoption(struct ast_channel *channel, int option, void *data, int datalen, int block);
01558 
01559 /*! Pick the best codec  */
01560 /* Choose the best codec...  Uhhh...   Yah. */
01561 int ast_best_codec(int fmts);
01562 
01563 
01564 /*! Checks the value of an option */
01565 /*!
01566  * Query the value of an option
01567  * Works similarly to setoption except only reads the options.
01568  */
01569 int ast_channel_queryoption(struct ast_channel *channel, int option, void *data, int *datalen, int block);
01570 
01571 /*! Checks for HTML support on a channel */
01572 /*! Returns 0 if channel does not support HTML or non-zero if it does */
01573 int ast_channel_supports_html(struct ast_channel *channel);
01574 
01575 /*! Sends HTML on given channel */
01576 /*! Send HTML or URL on link.  Returns 0 on success or -1 on failure */
01577 int ast_channel_sendhtml(struct ast_channel *channel, int subclass, const char *data, int datalen);
01578 
01579 /*! Sends a URL on a given link */
01580 /*! Send URL on link.  Returns 0 on success or -1 on failure */
01581 int ast_channel_sendurl(struct ast_channel *channel, const char *url);
01582 
01583 /*! Defers DTMF */
01584 /*! Defer DTMF so that you only read things like hangups and audio.  Returns
01585    non-zero if channel was already DTMF-deferred or 0 if channel is just now
01586    being DTMF-deferred */
01587 int ast_channel_defer_dtmf(struct ast_channel *chan);
01588 
01589 /*! Undo defer.  ast_read will return any dtmf characters that were queued */
01590 void ast_channel_undefer_dtmf(struct ast_channel *chan);
01591 
01592 /*! Initiate system shutdown -- prevents new channels from being allocated.
01593     If "hangup" is non-zero, all existing channels will receive soft
01594      hangups */
01595 void ast_begin_shutdown(int hangup);
01596 
01597 /*! Cancels an existing shutdown and returns to normal operation */
01598 void ast_cancel_shutdown(void);
01599 
01600 /*! Returns number of active/allocated channels */
01601 int ast_active_channels(void);
01602 
01603 /*! Returns non-zero if Asterisk is being shut down */
01604 int ast_shutting_down(void);
01605 
01606 /*! Activate a given generator */
01607 int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params);
01608 
01609 /*! Deactivate an active generator */
01610 void ast_deactivate_generator(struct ast_channel *chan);
01611 
01612 /*!
01613  * \brief Set caller ID number, name and ANI
01614  *
01615  * \note The channel does not need to be locked before calling this function.
01616  */
01617 void ast_set_callerid(struct ast_channel *chan, const char *cid_num, const char *cid_name, const char *cid_ani);
01618 
01619 /*! Set the file descriptor on the channel */
01620 void ast_channel_set_fd(struct ast_channel *chan, int which, int fd);
01621 
01622 /*! Add a channel to an optimized waitfor */
01623 void ast_poll_channel_add(struct ast_channel *chan0, struct ast_channel *chan1);
01624 
01625 /*! Delete a channel from an optimized waitfor */
01626 void ast_poll_channel_del(struct ast_channel *chan0, struct ast_channel *chan1);
01627 
01628 /*! Start a tone going */
01629 int ast_tonepair_start(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01630 /*! Stop a tone from playing */
01631 void ast_tonepair_stop(struct ast_channel *chan);
01632 /*! Play a tone pair for a given amount of time */
01633 int ast_tonepair(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01634 
01635 /*!
01636  * \brief Automatically service a channel for us...
01637  *
01638  * \retval 0 success
01639  * \retval -1 failure, or the channel is already being autoserviced
01640  */
01641 int ast_autoservice_start(struct ast_channel *chan);
01642 
01643 /*!
01644  * \brief Stop servicing a channel for us...
01645  *
01646  * \note if chan is locked prior to calling ast_autoservice_stop, it
01647  * is likely that there will be a deadlock between the thread that calls
01648  * ast_autoservice_stop and the autoservice thread. It is important
01649  * that chan is not locked prior to this call
01650  *
01651  * \retval 0 success
01652  * \retval -1 error, or the channel has been hungup
01653  */
01654 int ast_autoservice_stop(struct ast_channel *chan);
01655 
01656 /*!
01657  * \brief Ignore certain frame types
01658  * \note Normally, we cache DTMF, IMAGE, HTML, TEXT, and CONTROL frames
01659  * while a channel is in autoservice and queue them up when taken out of
01660  * autoservice.  When this is not desireable, this API may be used to
01661  * cause the channel to ignore those frametypes after the channel is put
01662  * into autoservice, but before autoservice is stopped.
01663  * \retval 0 success
01664  * \retval -1 channel is not in autoservice
01665  */
01666 int ast_autoservice_ignore(struct ast_channel *chan, enum ast_frame_type ftype);
01667 
01668 /*!
01669  * \brief Enable or disable timer ticks for a channel
01670  *
01671  * \param rate number of timer ticks per second
01672  *
01673  * If timers are supported, force a scheduled expiration on the
01674  * timer fd, at which point we call the callback function / data
01675  *
01676  * Call this function with a rate of 0 to turn off the timer ticks
01677  *
01678  * \version 1.6.1 changed samples parameter to rate, accomodates new timing methods
01679  */
01680 int ast_settimeout(struct ast_channel *c, unsigned int rate, int (*func)(const void *data), void *data);
01681 
01682 /*!   \brief Transfer a channel (if supported).  Returns -1 on error, 0 if not supported
01683    and 1 if supported and requested
01684    \param chan current channel
01685    \param dest destination extension for transfer
01686 */
01687 int ast_transfer(struct ast_channel *chan, char *dest);
01688 
01689 /*!   \brief  Start masquerading a channel
01690    XXX This is a seriously whacked out operation.  We're essentially putting the guts of
01691            the clone channel into the original channel.  Start by killing off the original
01692            channel's backend.   I'm not sure we're going to keep this function, because
01693            while the features are nice, the cost is very high in terms of pure nastiness. XXX
01694    \param chan    Channel to masquerade
01695 */
01696 int ast_do_masquerade(struct ast_channel *chan);
01697 
01698 /*!   \brief Find bridged channel
01699    \param chan Current channel
01700 */
01701 struct ast_channel *ast_bridged_channel(struct ast_channel *chan);
01702 
01703 /*!
01704   \brief Inherits channel variable from parent to child channel
01705   \param parent Parent channel
01706   \param child Child channel
01707 
01708   Scans all channel variables in the parent channel, looking for those
01709   that should be copied into the child channel.
01710   Variables whose names begin with a single '_' are copied into the
01711   child channel with the prefix removed.
01712   Variables whose names begin with '__' are copied into the child
01713   channel with their names unchanged.
01714 */
01715 void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child);
01716 
01717 /*!
01718   \brief adds a list of channel variables to a channel
01719   \param chan the channel
01720   \param vars a linked list of variables
01721 
01722   Variable names can be for a regular channel variable or a dialplan function
01723   that has the ability to be written to.
01724 */
01725 void ast_set_variables(struct ast_channel *chan, struct ast_variable *vars);
01726 
01727 /*!
01728   \brief An opaque 'object' structure use by silence generators on channels.
01729  */
01730 struct ast_silence_generator;
01731 
01732 /*!
01733   \brief Starts a silence generator on the given channel.
01734   \param chan The channel to generate silence on
01735   \return An ast_silence_generator pointer, or NULL if an error occurs
01736 
01737   This function will cause SLINEAR silence to be generated on the supplied
01738   channel until it is disabled; if the channel cannot be put into SLINEAR
01739   mode then the function will fail.
01740 
01741   The pointer returned by this function must be preserved and passed to
01742   ast_channel_stop_silence_generator when you wish to stop the silence
01743   generation.
01744  */
01745 struct ast_silence_generator *ast_channel_start_silence_generator(struct ast_channel *chan);
01746 
01747 /*!
01748   \brief Stops a previously-started silence generator on the given channel.
01749   \param chan The channel to operate on
01750   \param state The ast_silence_generator pointer return by a previous call to
01751   ast_channel_start_silence_generator.
01752   \return nothing
01753 
01754   This function will stop the operating silence generator and return the channel
01755   to its previous write format.
01756  */
01757 void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state);
01758 
01759 /*!
01760   \brief Check if the channel can run in internal timing mode.
01761   \param chan The channel to check
01762   \return boolean
01763 
01764   This function will return 1 if internal timing is enabled and the timing
01765   device is available.
01766  */
01767 int ast_internal_timing_enabled(struct ast_channel *chan);
01768 
01769 /* Misc. functions below */
01770 
01771 /*! \brief if fd is a valid descriptor, set *pfd with the descriptor
01772  * \return Return 1 (not -1!) if added, 0 otherwise (so we can add the
01773  * return value to the index into the array)
01774  */
01775 static inline int ast_add_fd(struct pollfd *pfd, int fd)
01776 {
01777    pfd->fd = fd;
01778    pfd->events = POLLIN | POLLPRI;
01779    return fd >= 0;
01780 }
01781 
01782 /*! \brief Helper function for migrating select to poll */
01783 static inline int ast_fdisset(struct pollfd *pfds, int fd, int maximum, int *start)
01784 {
01785    int x;
01786    int dummy = 0;
01787 
01788    if (fd < 0)
01789       return 0;
01790    if (!start)
01791       start = &dummy;
01792    for (x = *start; x < maximum; x++)
01793       if (pfds[x].fd == fd) {
01794          if (x == *start)
01795             (*start)++;
01796          return pfds[x].revents;
01797       }
01798    return 0;
01799 }
01800 
01801 /*! \brief Retrieves the current T38 state of a channel */
01802 static inline enum ast_t38_state ast_channel_get_t38_state(struct ast_channel *chan)
01803 {
01804    enum ast_t38_state state = T38_STATE_UNAVAILABLE;
01805    int datalen = sizeof(state);
01806 
01807    ast_channel_queryoption(chan, AST_OPTION_T38_STATE, &state, &datalen, 0);
01808 
01809    return state;
01810 }
01811 
01812 #define CHECK_BLOCKING(c) do {    \
01813    if (ast_test_flag(c, AST_FLAG_BLOCKING)) {\
01814       if (option_debug) \
01815          ast_log(LOG_DEBUG, "Thread %ld Blocking '%s', already blocked by thread %ld in procedure %s\n", (long) pthread_self(), (c)->name, (long) (c)->blocker, (c)->blockproc); \
01816    } else { \
01817       (c)->blocker = pthread_self(); \
01818       (c)->blockproc = __PRETTY_FUNCTION__; \
01819       ast_set_flag(c, AST_FLAG_BLOCKING); \
01820    } } while (0)
01821 
01822 ast_group_t ast_get_group(const char *s);
01823 
01824 /*! \brief print call- and pickup groups into buffer */
01825 char *ast_print_group(char *buf, int buflen, ast_group_t group);
01826 
01827 /*! \brief Convert enum channelreloadreason to text string for manager event
01828    \param reason  Enum channelreloadreason - reason for reload (manager, cli, start etc)
01829 */
01830 const char *channelreloadreason2txt(enum channelreloadreason reason);
01831 
01832 /*! \brief return an ast_variable list of channeltypes */
01833 struct ast_variable *ast_channeltype_list(void);
01834 
01835 /*!
01836   \brief return an english explanation of the code returned thru __ast_request_and_dial's 'outstate' argument
01837   \param reason  The integer argument, usually taken from AST_CONTROL_ macros
01838   \return char pointer explaining the code
01839  */
01840 const char *ast_channel_reason2str(int reason);
01841 
01842 /*! \brief channel group info
01843  */
01844 struct ast_group_info {
01845    struct ast_channel *chan;
01846    char *category;
01847    char *group;
01848    AST_LIST_ENTRY(ast_group_info) group_list;
01849 };
01850 
01851 
01852 #if defined(__cplusplus) || defined(c_plusplus)
01853 }
01854 #endif
01855 
01856 #endif /* _ASTERISK_CHANNEL_H */