Tue Apr 28 22:50:06 2009

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, ZAP, 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 
00085 */
00086 
00087 #ifndef _ASTERISK_CHANNEL_H
00088 #define _ASTERISK_CHANNEL_H
00089 
00090 #include "asterisk/abstract_jb.h"
00091 
00092 #include <unistd.h>
00093 #ifdef POLLCOMPAT 
00094 #include "asterisk/poll-compat.h"
00095 #else
00096 #include <sys/poll.h>
00097 #endif
00098 
00099 #if defined(__cplusplus) || defined(c_plusplus)
00100 extern "C" {
00101 #endif
00102 
00103 #define AST_MAX_EXTENSION  80 /*!< Max length of an extension */
00104 #define AST_MAX_CONTEXT    80 /*!< Max length of a context */
00105 #define AST_CHANNEL_NAME   80 /*!< Max length of an ast_channel name */
00106 #define MAX_LANGUAGE    20 /*!< Max length of the language setting */
00107 #define MAX_MUSICCLASS     80 /*!< Max length of the music class setting */
00108 
00109 #include "asterisk/compat.h"
00110 #include "asterisk/frame.h"
00111 #include "asterisk/sched.h"
00112 #include "asterisk/chanvars.h"
00113 #include "asterisk/config.h"
00114 #include "asterisk/lock.h"
00115 #include "asterisk/cdr.h"
00116 #include "asterisk/utils.h"
00117 #include "asterisk/linkedlists.h"
00118 #include "asterisk/stringfields.h"
00119 #include "asterisk/compiler.h"
00120 
00121 #define DATASTORE_INHERIT_FOREVER   INT_MAX
00122 
00123 #define AST_MAX_FDS     8
00124 /*
00125  * We have AST_MAX_FDS file descriptors in a channel.
00126  * Some of them have a fixed use:
00127  */
00128 #define AST_ALERT_FD (AST_MAX_FDS-1)      /*!< used for alertpipe */
00129 #define AST_TIMING_FD   (AST_MAX_FDS-2)      /*!< used for timingfd */
00130 #define AST_AGENT_FD (AST_MAX_FDS-3)      /*!< used by agents for pass through */
00131 #define AST_GENERATOR_FD   (AST_MAX_FDS-4)   /*!< used by generator */
00132 
00133 enum ast_bridge_result {
00134    AST_BRIDGE_COMPLETE = 0,
00135    AST_BRIDGE_FAILED = -1,
00136    AST_BRIDGE_FAILED_NOWARN = -2,
00137    AST_BRIDGE_RETRY = -3,
00138 };
00139 
00140 typedef unsigned long long ast_group_t;
00141 
00142 struct ast_generator {
00143    void *(*alloc)(struct ast_channel *chan, void *params);
00144    void (*release)(struct ast_channel *chan, void *data);
00145    /*! This function gets called with the channel unlocked, but is called in
00146     *  the context of the channel thread so we know the channel is not going
00147     *  to disappear.  This callback is responsible for locking the channel as
00148     *  necessary. */
00149    int (*generate)(struct ast_channel *chan, void *data, int len, int samples);
00150 };
00151 
00152 /*! \brief Structure for a data store type */
00153 struct ast_datastore_info {
00154    const char *type;    /*!< Type of data store */
00155    void *(*duplicate)(void *data); /*!< Duplicate item data (used for inheritance) */
00156    void (*destroy)(void *data);  /*!< Destroy function */
00157    /*!
00158     * \brief Fix up channel references
00159     *
00160     * \arg data The datastore data
00161     * \arg old_chan The old channel owning the datastore
00162     * \arg new_chan The new channel owning the datastore
00163     *
00164     * This is exactly like the fixup callback of the channel technology interface.
00165     * It allows a datastore to fix any pointers it saved to the owning channel
00166     * in case that the owning channel has changed.  Generally, this would happen
00167     * when the datastore is set to be inherited, and a masquerade occurs.
00168     *
00169     * \return nothing.
00170     */
00171    void (*chan_fixup)(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan);
00172 };
00173 
00174 /*! \brief Structure for a channel data store */
00175 struct ast_datastore {
00176    char *uid;     /*!< Unique data store identifier */
00177    void *data;    /*!< Contained data */
00178    const struct ast_datastore_info *info; /*!< Data store type information */
00179    unsigned int inheritance;  /*!Number of levels this item will continue to be inherited */
00180    AST_LIST_ENTRY(ast_datastore) entry; /*!< Used for easy linking */
00181 };
00182 
00183 /*! \brief Structure for all kinds of caller ID identifications.
00184  * \note All string fields here are malloc'ed, so they need to be
00185  * freed when the structure is deleted.
00186  * Also, NULL and "" must be considered equivalent.
00187  */
00188 struct ast_callerid {
00189    char *cid_dnid;      /*!< Malloc'd Dialed Number Identifier */
00190    char *cid_num;    /*!< Malloc'd Caller Number */
00191    char *cid_name;      /*!< Malloc'd Caller Name */
00192    char *cid_ani;    /*!< Malloc'd ANI */
00193    char *cid_rdnis;  /*!< Malloc'd RDNIS */
00194    int cid_pres;     /*!< Callerid presentation/screening */
00195    int cid_ani2;     /*!< Callerid ANI 2 (Info digits) */
00196    int cid_ton;      /*!< Callerid Type of Number */
00197    int cid_tns;      /*!< Callerid Transit Network Select */
00198 };
00199 
00200 /*! \brief 
00201    Structure to describe a channel "technology", ie a channel driver 
00202    See for examples:
00203    \arg chan_iax2.c - The Inter-Asterisk exchange protocol
00204    \arg chan_sip.c - The SIP channel driver
00205    \arg chan_zap.c - PSTN connectivity (TDM, PRI, T1/E1, FXO, FXS)
00206 
00207    If you develop your own channel driver, this is where you
00208    tell the PBX at registration of your driver what properties
00209    this driver supports and where different callbacks are 
00210    implemented.
00211 */
00212 struct ast_channel_tech {
00213    const char * const type;
00214    const char * const description;
00215 
00216    int capabilities;    /*!< Bitmap of formats this channel can handle */
00217 
00218    int properties;         /*!< Technology Properties */
00219 
00220    /*! \brief Requester - to set up call data structures (pvt's) */
00221    struct ast_channel *(* const requester)(const char *type, int format, void *data, int *cause);
00222 
00223    int (* const devicestate)(void *data); /*!< Devicestate call back */
00224 
00225    /*! \brief Start sending a literal DTMF digit */
00226    int (* const send_digit_begin)(struct ast_channel *chan, char digit);
00227 
00228    /*! \brief Stop sending a literal DTMF digit */
00229    int (* const send_digit_end)(struct ast_channel *chan, char digit, unsigned int duration);
00230 
00231    /*! \brief Call a given phone number (address, etc), but don't
00232       take longer than timeout seconds to do so.  */
00233    int (* const call)(struct ast_channel *chan, char *addr, int timeout);
00234 
00235    /*! \brief Hangup (and possibly destroy) the channel */
00236    int (* const hangup)(struct ast_channel *chan);
00237 
00238    /*! \brief Answer the channel */
00239    int (* const answer)(struct ast_channel *chan);
00240 
00241    /*! \brief Read a frame, in standard format (see frame.h) */
00242    struct ast_frame * (* const read)(struct ast_channel *chan);
00243 
00244    /*! \brief Write a frame, in standard format (see frame.h) */
00245    int (* const write)(struct ast_channel *chan, struct ast_frame *frame);
00246 
00247    /*! \brief Display or transmit text */
00248    int (* const send_text)(struct ast_channel *chan, const char *text);
00249 
00250    /*! \brief Display or send an image */
00251    int (* const send_image)(struct ast_channel *chan, struct ast_frame *frame);
00252 
00253    /*! \brief Send HTML data */
00254    int (* const send_html)(struct ast_channel *chan, int subclass, const char *data, int len);
00255 
00256    /*! \brief Handle an exception, reading a frame */
00257    struct ast_frame * (* const exception)(struct ast_channel *chan);
00258 
00259    /*! \brief Bridge two channels of the same type together */
00260    enum ast_bridge_result (* const bridge)(struct ast_channel *c0, struct ast_channel *c1, int flags,
00261                   struct ast_frame **fo, struct ast_channel **rc, int timeoutms);
00262 
00263    /*! \brief Indicate a particular condition (e.g. AST_CONTROL_BUSY or AST_CONTROL_RINGING or AST_CONTROL_CONGESTION */
00264    int (* const indicate)(struct ast_channel *c, int condition, const void *data, size_t datalen);
00265 
00266    /*! \brief Fix up a channel:  If a channel is consumed, this is called.  Basically update any ->owner links */
00267    int (* const fixup)(struct ast_channel *oldchan, struct ast_channel *newchan);
00268 
00269    /*! \brief Set a given option */
00270    int (* const setoption)(struct ast_channel *chan, int option, void *data, int datalen);
00271 
00272    /*! \brief Query a given option */
00273    int (* const queryoption)(struct ast_channel *chan, int option, void *data, int *datalen);
00274 
00275    /*! \brief Blind transfer other side (see app_transfer.c and ast_transfer() */
00276    int (* const transfer)(struct ast_channel *chan, const char *newdest);
00277 
00278    /*! \brief Write a frame, in standard format */
00279    int (* const write_video)(struct ast_channel *chan, struct ast_frame *frame);
00280 
00281    /*! \brief Find bridged channel */
00282    struct ast_channel *(* const bridged_channel)(struct ast_channel *chan, struct ast_channel *bridge);
00283 
00284    /*! \brief Provide additional read items for CHANNEL() dialplan function */
00285    int (* func_channel_read)(struct ast_channel *chan, char *function, char *data, char *buf, size_t len);
00286 
00287    /*! \brief Provide additional write items for CHANNEL() dialplan function */
00288    int (* func_channel_write)(struct ast_channel *chan, char *function, char *data, const char *value);
00289 
00290    /*! \brief Retrieve base channel (agent and local) */
00291    struct ast_channel* (* get_base_channel)(struct ast_channel *chan);
00292    
00293    /*! \brief Set base channel (agent and local) */
00294    int (* set_base_channel)(struct ast_channel *chan, struct ast_channel *base);
00295 };
00296 
00297 #define  DEBUGCHAN_FLAG  0x80000000
00298 #define  FRAMECOUNT_INC(x) ( ((x) & DEBUGCHAN_FLAG) | (((x)+1) & ~DEBUGCHAN_FLAG) )
00299 
00300 enum ast_channel_adsicpe {
00301    AST_ADSI_UNKNOWN,
00302    AST_ADSI_AVAILABLE,
00303    AST_ADSI_UNAVAILABLE,
00304    AST_ADSI_OFFHOOKONLY,
00305 };
00306 
00307 /*! 
00308  * \brief ast_channel states
00309  *
00310  * \note Bits 0-15 of state are reserved for the state (up/down) of the line
00311  *       Bits 16-32 of state are reserved for flags
00312  */
00313 enum ast_channel_state {
00314    /*! Channel is down and available */
00315    AST_STATE_DOWN,
00316    /*! Channel is down, but reserved */
00317    AST_STATE_RESERVED,
00318    /*! Channel is off hook */
00319    AST_STATE_OFFHOOK,
00320    /*! Digits (or equivalent) have been dialed */
00321    AST_STATE_DIALING,
00322    /*! Line is ringing */
00323    AST_STATE_RING,
00324    /*! Remote end is ringing */
00325    AST_STATE_RINGING,
00326    /*! Line is up */
00327    AST_STATE_UP,
00328    /*! Line is busy */
00329    AST_STATE_BUSY,
00330    /*! Digits (or equivalent) have been dialed while offhook */
00331    AST_STATE_DIALING_OFFHOOK,
00332    /*! Channel has detected an incoming call and is waiting for ring */
00333    AST_STATE_PRERING,
00334 
00335    /*! Do not transmit voice data */
00336    AST_STATE_MUTE = (1 << 16),
00337 };
00338 
00339 /*! \brief Main Channel structure associated with a channel. 
00340  * This is the side of it mostly used by the pbx and call management.
00341  *
00342  * \note XXX It is important to remember to increment .cleancount each time
00343  *       this structure is changed. XXX
00344  */
00345 struct ast_channel {
00346    /*! \brief Technology (point to channel driver) */
00347    const struct ast_channel_tech *tech;
00348 
00349    /*! \brief Private data used by the technology driver */
00350    void *tech_pvt;
00351 
00352    AST_DECLARE_STRING_FIELDS(
00353       AST_STRING_FIELD(name);       /*!< ASCII unique channel name */
00354       AST_STRING_FIELD(language);      /*!< Language requested for voice prompts */
00355       AST_STRING_FIELD(musicclass);    /*!< Default music class */
00356       AST_STRING_FIELD(accountcode);      /*!< Account code for billing */
00357       AST_STRING_FIELD(call_forward);     /*!< Where to forward to if asked to dial on this interface */
00358       AST_STRING_FIELD(uniqueid);      /*!< Unique Channel Identifier */
00359    );
00360    
00361    /*! \brief File descriptor for channel -- Drivers will poll on these file descriptors, so at least one must be non -1.  */
00362    int fds[AST_MAX_FDS];         
00363 
00364    void *music_state;            /*!< Music State*/
00365    void *generatordata;          /*!< Current generator data if there is any */
00366    struct ast_generator *generator;    /*!< Current active data generator */
00367 
00368    /*! \brief Who are we bridged to, if we're bridged. Who is proxying for us,
00369      if we are proxied (i.e. chan_agent).
00370      Do not access directly, use ast_bridged_channel(chan) */
00371    struct ast_channel *_bridge;
00372    struct ast_channel *masq;        /*!< Channel that will masquerade as us */
00373    struct ast_channel *masqr;       /*!< Who we are masquerading as */
00374    int cdrflags;              /*!< Call Detail Record Flags */
00375 
00376    /*! \brief Whether or not we have been hung up...  Do not set this value
00377        directly, use ast_softhangup */
00378    int _softhangup;
00379    time_t   whentohangup;           /*!< Non-zero, set to actual time when channel is to be hung up */
00380    pthread_t blocker;            /*!< If anyone is blocking, this is them */
00381    ast_mutex_t lock;          /*!< Lock, can be used to lock a channel for some operations */
00382    const char *blockproc;           /*!< Procedure causing blocking */
00383 
00384    const char *appl;          /*!< Current application */
00385    const char *data;          /*!< Data passed to current application */
00386    int fdno;               /*!< Which fd had an event detected on */
00387    struct sched_context *sched;        /*!< Schedule context */
00388    int streamid;              /*!< For streaming playback, the schedule ID */
00389    struct ast_filestream *stream;         /*!< Stream itself. */
00390    int vstreamid;             /*!< For streaming video playback, the schedule ID */
00391    struct ast_filestream *vstream;        /*!< Video Stream itself. */
00392    int oldwriteformat;           /*!< Original writer format */
00393    
00394    int timingfd;              /*!< Timing fd */
00395    int (*timingfunc)(const void *data);
00396    void *timingdata;
00397 
00398    enum ast_channel_state _state;         /*!< State of line -- Don't write directly, use ast_setstate */
00399    int rings;              /*!< Number of rings so far */
00400    struct ast_callerid cid;         /*!< Caller ID, name, presentation etc */
00401    char unused_old_dtmfq[AST_MAX_EXTENSION]; /*!< The DTMFQ is deprecated.  All frames should go to the readq. */
00402    struct ast_frame dtmff;          /*!< DTMF frame */
00403 
00404    char context[AST_MAX_CONTEXT];         /*!< Dialplan: Current extension context */
00405    char exten[AST_MAX_EXTENSION];         /*!< Dialplan: Current extension number */
00406    int priority;              /*!< Dialplan: Current extension priority */
00407    char macrocontext[AST_MAX_CONTEXT];    /*!< Macro: Current non-macro context. See app_macro.c */
00408    char macroexten[AST_MAX_EXTENSION];    /*!< Macro: Current non-macro extension. See app_macro.c */
00409    int macropriority;            /*!< Macro: Current non-macro priority. See app_macro.c */
00410    char dialcontext[AST_MAX_CONTEXT];              /*!< Dial: Extension context that we were called from */
00411 
00412    struct ast_pbx *pbx;          /*!< PBX private structure for this channel */
00413    int amaflags;              /*!< Set BEFORE PBX is started to determine AMA flags */
00414    struct ast_cdr *cdr;          /*!< Call Detail Record */
00415    enum ast_channel_adsicpe adsicpe;      /*!< Whether or not ADSI is detected on CPE */
00416 
00417    struct tone_zone *zone;          /*!< Tone zone as set in indications.conf or
00418                         in the CHANNEL dialplan function */
00419 
00420    struct ast_channel_monitor *monitor;      /*!< Channel monitoring */
00421 
00422    /*! Track the read/written samples for monitor use */
00423    unsigned long insmpl;
00424    unsigned long outsmpl;
00425 
00426    /* Frames in/out counters. The high bit is a debug mask, so
00427     * the counter is only in the remaining bits
00428     */
00429    unsigned int fin;
00430    unsigned int fout;
00431    int hangupcause;           /*!< Why is the channel hanged up. See causes.h */
00432    struct varshead varshead;        /*!< A linked list for channel variables */
00433    ast_group_t callgroup;           /*!< Call group for call pickups */
00434    ast_group_t pickupgroup;         /*!< Pickup group - which calls groups can be picked up? */
00435    unsigned int flags;           /*!< channel flags of AST_FLAG_ type */
00436    unsigned short transfercapability;     /*!< ISDN Transfer Capbility - AST_FLAG_DIGITAL is not enough */
00437    AST_LIST_HEAD_NOLOCK(, ast_frame) readq;
00438    int alertpipe[2];
00439 
00440    int nativeformats;            /*!< Kinds of data this channel can natively handle */
00441    int readformat;               /*!< Requested read format */
00442    int writeformat;           /*!< Requested write format */
00443    struct ast_trans_pvt *writetrans;      /*!< Write translation path */
00444    struct ast_trans_pvt *readtrans;    /*!< Read translation path */
00445    int rawreadformat;            /*!< Raw read format */
00446    int rawwriteformat;           /*!< Raw write format */
00447 
00448    struct ast_audiohook_list *audiohooks;
00449    void *unused; /*! This pointer should stay for Asterisk 1.4.  It just keeps the struct size the same
00450           *  for the sake of ABI compatability. */
00451 
00452    AST_LIST_ENTRY(ast_channel) chan_list;    /*!< For easy linking */
00453    
00454    struct ast_jb jb;          /*!< The jitterbuffer state  */
00455 
00456    char emulate_dtmf_digit;         /*!< Digit being emulated */
00457    unsigned int emulate_dtmf_duration; /*!< Number of ms left to emulate DTMF for */
00458    struct timeval dtmf_tv;       /*!< The time that an in process digit began, or the last digit ended */
00459 
00460    int visible_indication;                         /*!< Indication currently playing on the channel */
00461 
00462    /*! \brief Data stores on the channel */
00463    AST_LIST_HEAD_NOLOCK(datastores, ast_datastore) datastores;
00464 };
00465 
00466 /*! \brief ast_channel_tech Properties */
00467 enum {
00468    /*! \brief Channels have this property if they can accept input with jitter; 
00469     *         i.e. most VoIP channels */
00470    AST_CHAN_TP_WANTSJITTER = (1 << 0),
00471    /*! \brief Channels have this property if they can create jitter; 
00472     *         i.e. most VoIP channels */
00473    AST_CHAN_TP_CREATESJITTER = (1 << 1),
00474 };
00475 
00476 /*! \brief ast_channel flags */
00477 enum {
00478    /*! Queue incoming dtmf, to be released when this flag is turned off */
00479    AST_FLAG_DEFER_DTMF =    (1 << 1),
00480    /*! write should be interrupt generator */
00481    AST_FLAG_WRITE_INT =     (1 << 2),
00482    /*! a thread is blocking on this channel */
00483    AST_FLAG_BLOCKING =      (1 << 3),
00484    /*! This is a zombie channel */
00485    AST_FLAG_ZOMBIE =        (1 << 4),
00486    /*! There is an exception pending */
00487    AST_FLAG_EXCEPTION =     (1 << 5),
00488    /*! Listening to moh XXX anthm promises me this will disappear XXX */
00489    AST_FLAG_MOH =           (1 << 6),
00490    /*! This channel is spying on another channel */
00491    AST_FLAG_SPYING =        (1 << 7),
00492    /*! This channel is in a native bridge */
00493    AST_FLAG_NBRIDGE =       (1 << 8),
00494    /*! the channel is in an auto-incrementing dialplan processor,
00495     *  so when ->priority is set, it will get incremented before
00496     *  finding the next priority to run */
00497    AST_FLAG_IN_AUTOLOOP =   (1 << 9),
00498    /*! This is an outgoing call */
00499    AST_FLAG_OUTGOING =      (1 << 10),
00500    /*! This channel is being whispered on */
00501    AST_FLAG_WHISPER =       (1 << 11),
00502    /*! A DTMF_BEGIN frame has been read from this channel, but not yet an END */
00503    AST_FLAG_IN_DTMF =       (1 << 12),
00504    /*! A DTMF_END was received when not IN_DTMF, so the length of the digit is 
00505     *  currently being emulated */
00506    AST_FLAG_EMULATE_DTMF =  (1 << 13),
00507    /*! This is set to tell the channel not to generate DTMF begin frames, and
00508     *  to instead only generate END frames. */
00509    AST_FLAG_END_DTMF_ONLY = (1 << 14),
00510    /*! This flag indicates that on a masquerade, an active stream should not
00511     *  be carried over */
00512    AST_FLAG_MASQ_NOSTREAM = (1 << 15),
00513    /*! This flag indicates that the hangup exten was run when the bridge terminated,
00514     *  a message aimed at preventing a subsequent hangup exten being run at the pbx_run
00515     *  level */
00516    AST_FLAG_BRIDGE_HANGUP_RUN = (1 << 16),
00517    /*! This flag indicates that the hangup exten should NOT be run when the 
00518     *  bridge terminates, this will allow the hangup in the pbx loop to be run instead.
00519     *  */
00520    AST_FLAG_BRIDGE_HANGUP_DONT = (1 << 17),
00521 };
00522 
00523 /*! \brief ast_bridge_config flags */
00524 enum {
00525    AST_FEATURE_PLAY_WARNING = (1 << 0),
00526    AST_FEATURE_REDIRECT =     (1 << 1),
00527    AST_FEATURE_DISCONNECT =   (1 << 2),
00528    AST_FEATURE_ATXFER =       (1 << 3),
00529    AST_FEATURE_AUTOMON =      (1 << 4),
00530    AST_FEATURE_PARKCALL =     (1 << 5),
00531    AST_FEATURE_NO_H_EXTEN =   (1 << 6),
00532    AST_FEATURE_WARNING_ACTIVE = (1 << 7),
00533 };
00534 
00535 struct ast_bridge_config {
00536    struct ast_flags features_caller;
00537    struct ast_flags features_callee;
00538    struct timeval start_time;
00539    struct timeval nexteventts;
00540    long feature_timer;
00541    long timelimit;
00542    long play_warning;
00543    long warning_freq;
00544    const char *warning_sound;
00545    const char *end_sound;
00546    const char *start_sound;
00547    int firstpass;
00548    unsigned int flags;
00549    void (* end_bridge_callback)(void *);   /*!< A callback that is called after a bridge attempt */
00550    void *end_bridge_callback_data;         /*!< Data passed to the callback */
00551    /*! If the end_bridge_callback_data refers to a channel which no longer is going to
00552     * exist when the end_bridge_callback is called, then it needs to be fixed up properly
00553     */
00554    void (*end_bridge_callback_data_fixup)(struct ast_bridge_config *bconfig, struct ast_channel *originator, struct ast_channel *terminator);
00555 };
00556 
00557 struct chanmon;
00558 
00559 #define LOAD_OH(oh) {   \
00560    oh.context = context; \
00561    oh.exten = exten; \
00562    oh.priority = priority; \
00563    oh.cid_num = cid_num; \
00564    oh.cid_name = cid_name; \
00565    oh.account = account; \
00566    oh.vars = vars; \
00567    oh.parent_channel = NULL; \
00568 } 
00569 
00570 struct outgoing_helper {
00571    const char *context;
00572    const char *exten;
00573    int priority;
00574    const char *cid_num;
00575    const char *cid_name;
00576    const char *account;
00577    struct ast_variable *vars;
00578    struct ast_channel *parent_channel;
00579 };
00580 
00581 enum {
00582    AST_CDR_TRANSFER =   (1 << 0),
00583    AST_CDR_FORWARD =    (1 << 1),
00584    AST_CDR_CALLWAIT =   (1 << 2),
00585    AST_CDR_CONFERENCE = (1 << 3),
00586 };
00587 
00588 enum {
00589    /*! Soft hangup by device */
00590    AST_SOFTHANGUP_DEV =       (1 << 0),
00591    /*! Soft hangup for async goto */
00592    AST_SOFTHANGUP_ASYNCGOTO = (1 << 1),
00593    AST_SOFTHANGUP_SHUTDOWN =  (1 << 2),
00594    AST_SOFTHANGUP_TIMEOUT =   (1 << 3),
00595    AST_SOFTHANGUP_APPUNLOAD = (1 << 4),
00596    AST_SOFTHANGUP_EXPLICIT =  (1 << 5),
00597    AST_SOFTHANGUP_UNBRIDGE =  (1 << 6),
00598 };
00599 
00600 
00601 /*! \brief Channel reload reasons for manager events at load or reload of configuration */
00602 enum channelreloadreason {
00603    CHANNEL_MODULE_LOAD,
00604    CHANNEL_MODULE_RELOAD,
00605    CHANNEL_CLI_RELOAD,
00606    CHANNEL_MANAGER_RELOAD,
00607 };
00608 
00609 /*! \brief Create a channel datastore structure */
00610 struct ast_datastore *ast_channel_datastore_alloc(const struct ast_datastore_info *info, char *uid);
00611 
00612 /*! \brief Free a channel datastore structure */
00613 int ast_channel_datastore_free(struct ast_datastore *datastore);
00614 
00615 /*! \brief Inherit datastores from a parent to a child. */
00616 int ast_channel_datastore_inherit(struct ast_channel *from, struct ast_channel *to);
00617 
00618 /*! \brief Add a datastore to a channel */
00619 int ast_channel_datastore_add(struct ast_channel *chan, struct ast_datastore *datastore);
00620 
00621 /*! \brief Remove a datastore from a channel */
00622 int ast_channel_datastore_remove(struct ast_channel *chan, struct ast_datastore *datastore);
00623 
00624 /*! \brief Find a datastore on a channel */
00625 struct ast_datastore *ast_channel_datastore_find(struct ast_channel *chan, const struct ast_datastore_info *info, char *uid);
00626 
00627 /*! \brief Change the state of a channel */
00628 int ast_setstate(struct ast_channel *chan, enum ast_channel_state);
00629 
00630 /*! \brief Create a channel structure 
00631     \return Returns NULL on failure to allocate.
00632    \note New channels are 
00633    by default set to the "default" context and
00634    extension "s"
00635  */
00636 struct ast_channel *ast_channel_alloc(int needqueue, int state, const char *cid_num, const char *cid_name, const char *acctcode, const char *exten, const char *context, const int amaflag, const char *name_fmt, ...) __attribute__((format(printf, 9, 10)));
00637 
00638 /*! \brief Queue an outgoing frame */
00639 int ast_queue_frame(struct ast_channel *chan, struct ast_frame *f);
00640 
00641 /*!
00642  * \brief Queue an outgoing frame to the head of the frame queue
00643  *
00644  * \param chan the channel to queue the frame on
00645  * \param f the frame to queue.  Note that this frame will be duplicated by
00646  *        this function.  It is the responsibility of the caller to handle
00647  *        freeing the memory associated with the frame being passed if
00648  *        necessary.
00649  *
00650  * \retval 0 success
00651  * \retval non-zero failure
00652  */
00653 int ast_queue_frame_head(struct ast_channel *chan, struct ast_frame *f);
00654 
00655 /*! \brief Queue a hangup frame */
00656 int ast_queue_hangup(struct ast_channel *chan);
00657 
00658 /*!
00659   \brief Queue a control frame with payload
00660   \param chan channel to queue frame onto
00661   \param control type of control frame
00662   \return zero on success, non-zero on failure
00663 */
00664 int ast_queue_control(struct ast_channel *chan, enum ast_control_frame_type control);
00665 
00666 /*!
00667   \brief Queue a control frame with payload
00668   \param chan channel to queue frame onto
00669   \param control type of control frame
00670   \param data pointer to payload data to be included in frame
00671   \param datalen number of bytes of payload data
00672   \return zero on success, non-zero on failure
00673 
00674   The supplied payload data is copied into the frame, so the caller's copy
00675   is not modified nor freed, and the resulting frame will retain a copy of
00676   the data even if the caller frees their local copy.
00677 
00678   \note This method should be treated as a 'network transport'; in other
00679   words, your frames may be transferred across an IAX2 channel to another
00680   system, which may be a different endianness than yours. Because of this,
00681   you should ensure that either your frames will never be expected to work
00682   across systems, or that you always put your payload data into 'network byte
00683   order' before calling this function.
00684 */
00685 int ast_queue_control_data(struct ast_channel *chan, enum ast_control_frame_type control,
00686             const void *data, size_t datalen);
00687 
00688 /*! \brief Change channel name */
00689 void ast_change_name(struct ast_channel *chan, char *newname);
00690 
00691 /*! \brief Free a channel structure */
00692 void  ast_channel_free(struct ast_channel *);
00693 
00694 /*! \brief Requests a channel 
00695  * \param type type of channel to request
00696  * \param format requested channel format (codec)
00697  * \param data data to pass to the channel requester
00698  * \param status status
00699  * Request a channel of a given type, with data as optional information used 
00700  * by the low level module
00701  * \return Returns an ast_channel on success, NULL on failure.
00702  */
00703 struct ast_channel *ast_request(const char *type, int format, void *data, int *status);
00704 
00705 /*!
00706  * \brief Request a channel of a given type, with data as optional information used 
00707  * by the low level module and attempt to place a call on it
00708  * \param type type of channel to request
00709  * \param format requested channel format
00710  * \param data data to pass to the channel requester
00711  * \param timeout maximum amount of time to wait for an answer
00712  * \param reason why unsuccessful (if unsuceessful)
00713  * \param cidnum Caller-ID Number
00714  * \param cidname Caller-ID Name
00715  * \return Returns an ast_channel on success or no answer, NULL on failure.  Check the value of chan->_state
00716  * to know if the call was answered or not.
00717  */
00718 struct ast_channel *ast_request_and_dial(const char *type, int format, void *data, int timeout, int *reason, const char *cidnum, const char *cidname);
00719 
00720 struct ast_channel *__ast_request_and_dial(const char *type, int format, void *data, int timeout, int *reason, const char *cidnum, const char *cidname, struct outgoing_helper *oh);
00721 
00722 /*!\brief Register a channel technology (a new channel driver)
00723  * Called by a channel module to register the kind of channels it supports.
00724  * \param tech Structure defining channel technology or "type"
00725  * \return Returns 0 on success, -1 on failure.
00726  */
00727 int ast_channel_register(const struct ast_channel_tech *tech);
00728 
00729 /*! \brief Unregister a channel technology 
00730  * \param tech Structure defining channel technology or "type" that was previously registered
00731  * \return No return value.
00732  */
00733 void ast_channel_unregister(const struct ast_channel_tech *tech);
00734 
00735 /*! \brief Get a channel technology structure by name
00736  * \param name name of technology to find
00737  * \return a pointer to the structure, or NULL if no matching technology found
00738  */
00739 const struct ast_channel_tech *ast_get_channel_tech(const char *name);
00740 
00741 /*! \brief Hang up a channel  
00742  * \note This function performs a hard hangup on a channel.  Unlike the soft-hangup, this function
00743  * performs all stream stopping, etc, on the channel that needs to end.
00744  * chan is no longer valid after this call.
00745  * \param chan channel to hang up
00746  * \return Returns 0 on success, -1 on failure.
00747  */
00748 int ast_hangup(struct ast_channel *chan);
00749 
00750 /*! \brief Softly hangup up a channel 
00751  * \param chan channel to be soft-hung-up
00752  * Call the protocol layer, but don't destroy the channel structure (use this if you are trying to
00753  * safely hangup a channel managed by another thread.
00754  * \param cause   Ast hangupcause for hangup
00755  * \return Returns 0 regardless
00756  */
00757 int ast_softhangup(struct ast_channel *chan, int cause);
00758 
00759 /*! \brief Softly hangup up a channel (no channel lock) 
00760  * \param chan channel to be soft-hung-up
00761  * \param cause   Ast hangupcause for hangup (see cause.h) */
00762 int ast_softhangup_nolock(struct ast_channel *chan, int cause);
00763 
00764 /*! \brief Check to see if a channel is needing hang up 
00765  * \param chan channel on which to check for hang up
00766  * This function determines if the channel is being requested to be hung up.
00767  * \return Returns 0 if not, or 1 if hang up is requested (including time-out).
00768  */
00769 int ast_check_hangup(struct ast_channel *chan);
00770 
00771 /*! \brief Compare a offset with the settings of when to hang a channel up 
00772  * \param chan channel on which to check for hang up
00773  * \param offset offset in seconds from current time
00774  * \return 1, 0, or -1
00775  * This function compares a offset from current time with the absolute time 
00776  * out on a channel (when to hang up). If the absolute time out on a channel
00777  * is earlier than current time plus the offset, it returns 1, if the two
00778  * time values are equal, it return 0, otherwise, it retturn -1.
00779  */
00780 int ast_channel_cmpwhentohangup(struct ast_channel *chan, time_t offset);
00781 
00782 /*! \brief Set when to hang a channel up 
00783  * \param chan channel on which to check for hang up
00784  * \param offset offset in seconds from current time of when to hang up
00785  * This function sets the absolute time out on a channel (when to hang up).
00786  */
00787 void ast_channel_setwhentohangup(struct ast_channel *chan, time_t offset);
00788 
00789 /*! \brief Answer a ringing call 
00790  * \param chan channel to answer
00791  * This function answers a channel and handles all necessary call
00792  * setup functions.
00793  * \return Returns 0 on success, -1 on failure
00794  */
00795 int ast_answer(struct ast_channel *chan);
00796 
00797 /*! \brief Make a call 
00798  * \param chan which channel to make the call on
00799  * \param addr destination of the call
00800  * \param timeout time to wait on for connect
00801  * Place a call, take no longer than timeout ms. 
00802    \return Returns -1 on failure, 0 on not enough time 
00803    (does not automatically stop ringing), and  
00804    the number of seconds the connect took otherwise.
00805    */
00806 int ast_call(struct ast_channel *chan, char *addr, int timeout);
00807 
00808 /*! \brief Indicates condition of channel 
00809  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
00810  * \param chan channel to change the indication
00811  * \param condition which condition to indicate on the channel
00812  * \return Returns 0 on success, -1 on failure
00813  */
00814 int ast_indicate(struct ast_channel *chan, int condition);
00815 
00816 /*! \brief Indicates condition of channel, with payload
00817  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
00818  * \param chan channel to change the indication
00819  * \param condition which condition to indicate on the channel
00820  * \param data pointer to payload data
00821  * \param datalen size of payload data
00822  * \return Returns 0 on success, -1 on failure
00823  */
00824 int ast_indicate_data(struct ast_channel *chan, int condition, const void *data, size_t datalen);
00825 
00826 /* Misc stuff ------------------------------------------------ */
00827 
00828 /*! \brief Wait for input on a channel 
00829  * \param chan channel to wait on
00830  * \param ms length of time to wait on the channel
00831  * Wait for input on a channel for a given # of milliseconds (<0 for indefinite). 
00832   \return Returns < 0 on  failure, 0 if nothing ever arrived, and the # of ms remaining otherwise */
00833 int ast_waitfor(struct ast_channel *chan, int ms);
00834 
00835 /*! \brief Wait for a specied amount of time, looking for hangups 
00836  * \param chan channel to wait for
00837  * \param ms length of time in milliseconds to sleep
00838  * Waits for a specified amount of time, servicing the channel as required.
00839  * \return returns -1 on hangup, otherwise 0.
00840  */
00841 int ast_safe_sleep(struct ast_channel *chan, int ms);
00842 
00843 /*! \brief Wait for a specied amount of time, looking for hangups and a condition argument 
00844  * \param chan channel to wait for
00845  * \param ms length of time in milliseconds to sleep
00846  * \param cond a function pointer for testing continue condition
00847  * \param data argument to be passed to the condition test function
00848  * \return returns -1 on hangup, otherwise 0.
00849  * Waits for a specified amount of time, servicing the channel as required. If cond
00850  * returns 0, this function returns.
00851  */
00852 int ast_safe_sleep_conditional(struct ast_channel *chan, int ms, int (*cond)(void*), void *data );
00853 
00854 /*! \brief Waits for activity on a group of channels 
00855  * \param chan an array of pointers to channels
00856  * \param n number of channels that are to be waited upon
00857  * \param fds an array of fds to wait upon
00858  * \param nfds the number of fds to wait upon
00859  * \param exception exception flag
00860  * \param outfd fd that had activity on it
00861  * \param ms how long the wait was
00862  * Big momma function here.  Wait for activity on any of the n channels, or any of the nfds
00863    file descriptors.
00864    \return Returns the channel with activity, or NULL on error or if an FD
00865    came first.  If the FD came first, it will be returned in outfd, otherwise, outfd
00866    will be -1 */
00867 struct ast_channel *ast_waitfor_nandfds(struct ast_channel **chan, int n, int *fds, int nfds, int *exception, int *outfd, int *ms);
00868 
00869 /*! \brief Waits for input on a group of channels
00870    Wait for input on an array of channels for a given # of milliseconds. 
00871    \return Return channel with activity, or NULL if none has activity.  
00872    \param chan an array of pointers to channels
00873    \param n number of channels that are to be waited upon
00874    \param ms time "ms" is modified in-place, if applicable */
00875 struct ast_channel *ast_waitfor_n(struct ast_channel **chan, int n, int *ms);
00876 
00877 /*! \brief Waits for input on an fd
00878    This version works on fd's only.  Be careful with it. */
00879 int ast_waitfor_n_fd(int *fds, int n, int *ms, int *exception);
00880 
00881 
00882 /*! \brief Reads a frame
00883  * \param chan channel to read a frame from
00884    Read a frame.  
00885    \return Returns a frame, or NULL on error.  If it returns NULL, you
00886       best just stop reading frames and assume the channel has been
00887       disconnected. */
00888 struct ast_frame *ast_read(struct ast_channel *chan);
00889 
00890 /*! \brief Reads a frame, returning AST_FRAME_NULL frame if audio. 
00891  * Read a frame. 
00892    \param chan channel to read a frame from
00893    \return  Returns a frame, or NULL on error.  If it returns NULL, you
00894       best just stop reading frames and assume the channel has been
00895       disconnected.  
00896    \note Audio is replaced with AST_FRAME_NULL to avoid 
00897    transcode when the resulting audio is not necessary. */
00898 struct ast_frame *ast_read_noaudio(struct ast_channel *chan);
00899 
00900 /*! \brief Write a frame to a channel 
00901  * This function writes the given frame to the indicated channel.
00902  * \param chan destination channel of the frame
00903  * \param frame frame that will be written
00904  * \return It returns 0 on success, -1 on failure.
00905  */
00906 int ast_write(struct ast_channel *chan, struct ast_frame *frame);
00907 
00908 /*! \brief Write video frame to a channel 
00909  * This function writes the given frame to the indicated channel.
00910  * \param chan destination channel of the frame
00911  * \param frame frame that will be written
00912  * \return It returns 1 on success, 0 if not implemented, and -1 on failure.
00913  */
00914 int ast_write_video(struct ast_channel *chan, struct ast_frame *frame);
00915 
00916 /*! \brief Send empty audio to prime a channel driver */
00917 int ast_prod(struct ast_channel *chan);
00918 
00919 /*! \brief Sets read format on channel chan
00920  * Set read format for channel to whichever component of "format" is best. 
00921  * \param chan channel to change
00922  * \param format format to change to
00923  * \return Returns 0 on success, -1 on failure
00924  */
00925 int ast_set_read_format(struct ast_channel *chan, int format);
00926 
00927 /*! \brief Sets write format on channel chan
00928  * Set write format for channel to whichever compoent of "format" is best. 
00929  * \param chan channel to change
00930  * \param format new format for writing
00931  * \return Returns 0 on success, -1 on failure
00932  */
00933 int ast_set_write_format(struct ast_channel *chan, int format);
00934 
00935 /*! \brief Sends text to a channel 
00936  * Write text to a display on a channel
00937  * \param chan channel to act upon
00938  * \param text string of text to send on the channel
00939  * \return Returns 0 on success, -1 on failure
00940  */
00941 int ast_sendtext(struct ast_channel *chan, const char *text);
00942 
00943 /*! \brief Receives a text character from a channel
00944  * \param chan channel to act upon
00945  * \param timeout timeout in milliseconds (0 for infinite wait)
00946  * Read a char of text from a channel
00947  * Returns 0 on success, -1 on failure
00948  */
00949 int ast_recvchar(struct ast_channel *chan, int timeout);
00950 
00951 /*! \brief Send a DTMF digit to a channel
00952  * Send a DTMF digit to a channel.
00953  * \param chan channel to act upon
00954  * \param digit the DTMF digit to send, encoded in ASCII
00955  * \return Returns 0 on success, -1 on failure
00956  */
00957 int ast_senddigit(struct ast_channel *chan, char digit);
00958 
00959 int ast_senddigit_begin(struct ast_channel *chan, char digit);
00960 int ast_senddigit_end(struct ast_channel *chan, char digit, unsigned int duration);
00961 
00962 /*! \brief Receives a text string from a channel
00963  * Read a string of text from a channel
00964  * \param chan channel to act upon
00965  * \param timeout timeout in milliseconds (0 for infinite wait)
00966  * \return the received text, or NULL to signify failure.
00967  */
00968 char *ast_recvtext(struct ast_channel *chan, int timeout);
00969 
00970 /*! \brief Browse channels in use
00971  * Browse the channels currently in use 
00972  * \param prev where you want to start in the channel list
00973  * \return Returns the next channel in the list, NULL on end.
00974  *    If it returns a channel, that channel *has been locked*!
00975  */
00976 struct ast_channel *ast_channel_walk_locked(const struct ast_channel *prev);
00977 
00978 /*! \brief Get channel by name (locks channel) */
00979 struct ast_channel *ast_get_channel_by_name_locked(const char *chan);
00980 
00981 /*! \brief Get channel by name prefix (locks channel) */
00982 struct ast_channel *ast_get_channel_by_name_prefix_locked(const char *name, const int namelen);
00983 
00984 /*! \brief Get channel by name prefix (locks channel) */
00985 struct ast_channel *ast_walk_channel_by_name_prefix_locked(const struct ast_channel *chan, const char *name, const int namelen);
00986 
00987 /*! \brief Get channel by exten (and optionally context) and lock it */
00988 struct ast_channel *ast_get_channel_by_exten_locked(const char *exten, const char *context);
00989 
00990 /*! \brief Get next channel by exten (and optionally context) and lock it */
00991 struct ast_channel *ast_walk_channel_by_exten_locked(const struct ast_channel *chan, const char *exten,
00992                        const char *context);
00993 
00994 /*! ! \brief Waits for a digit
00995  * \param c channel to wait for a digit on
00996  * \param ms how many milliseconds to wait
00997  * \return Returns <0 on error, 0 on no entry, and the digit on success. */
00998 int ast_waitfordigit(struct ast_channel *c, int ms);
00999 
01000 /*! \brief Wait for a digit
01001  Same as ast_waitfordigit() with audio fd for outputting read audio and ctrlfd to monitor for reading. 
01002  * \param c channel to wait for a digit on
01003  * \param ms how many milliseconds to wait
01004  * \param audiofd audio file descriptor to write to if audio frames are received
01005  * \param ctrlfd control file descriptor to monitor for reading
01006  * \return Returns 1 if ctrlfd becomes available */
01007 int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int ctrlfd);
01008 
01009 /*! Reads multiple digits 
01010  * \param c channel to read from
01011  * \param s string to read in to.  Must be at least the size of your length
01012  * \param len how many digits to read (maximum)
01013  * \param timeout how long to timeout between digits
01014  * \param rtimeout timeout to wait on the first digit
01015  * \param enders digits to end the string
01016  * Read in a digit string "s", max length "len", maximum timeout between 
01017    digits "timeout" (-1 for none), terminated by anything in "enders".  Give them rtimeout
01018    for the first digit.  Returns 0 on normal return, or 1 on a timeout.  In the case of
01019    a timeout, any digits that were read before the timeout will still be available in s.  
01020    RETURNS 2 in full version when ctrlfd is available, NOT 1*/
01021 int ast_readstring(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders);
01022 int ast_readstring_full(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders, int audiofd, int ctrlfd);
01023 
01024 /*! \brief Report DTMF on channel 0 */
01025 #define AST_BRIDGE_DTMF_CHANNEL_0      (1 << 0)    
01026 /*! \brief Report DTMF on channel 1 */
01027 #define AST_BRIDGE_DTMF_CHANNEL_1      (1 << 1)    
01028 /*! \brief Return all voice frames on channel 0 */
01029 #define AST_BRIDGE_REC_CHANNEL_0    (1 << 2)    
01030 /*! \brief Return all voice frames on channel 1 */
01031 #define AST_BRIDGE_REC_CHANNEL_1    (1 << 3)    
01032 /*! \brief Ignore all signal frames except NULL */
01033 #define AST_BRIDGE_IGNORE_SIGS         (1 << 4)    
01034 
01035 
01036 /*! \brief Makes two channel formats compatible 
01037  * \param c0 first channel to make compatible
01038  * \param c1 other channel to make compatible
01039  * Set two channels to compatible formats -- call before ast_channel_bridge in general .  
01040  * \return Returns 0 on success and -1 if it could not be done */
01041 int ast_channel_make_compatible(struct ast_channel *c0, struct ast_channel *c1);
01042 
01043 /*! Bridge two channels together 
01044  * \param c0 first channel to bridge
01045  * \param c1 second channel to bridge
01046  * \param config config for the channels
01047  * \param fo destination frame(?)
01048  * \param rc destination channel(?)
01049  * Bridge two channels (c0 and c1) together.  If an important frame occurs, we return that frame in
01050    *rf (remember, it could be NULL) and which channel (0 or 1) in rc */
01051 /* int ast_channel_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc); */
01052 int ast_channel_bridge(struct ast_channel *c0,struct ast_channel *c1,struct ast_bridge_config *config, struct ast_frame **fo, struct ast_channel **rc);
01053 
01054 /*! \brief Weird function made for call transfers
01055  * \param original channel to make a copy of
01056  * \param clone copy of the original channel
01057  * This is a very strange and freaky function used primarily for transfer.  Suppose that
01058    "original" and "clone" are two channels in random situations.  This function takes
01059    the guts out of "clone" and puts them into the "original" channel, then alerts the
01060    channel driver of the change, asking it to fixup any private information (like the
01061    p->owner pointer) that is affected by the change.  The physical layer of the original
01062    channel is hung up.  */
01063 int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clone);
01064 
01065 /*! Gives the string form of a given cause code */
01066 /*! 
01067  * \param state cause to get the description of
01068  * Give a name to a cause code
01069  * Returns the text form of the binary cause code given
01070  */
01071 const char *ast_cause2str(int state) attribute_pure;
01072 
01073 /*! Convert the string form of a cause code to a number */
01074 /*! 
01075  * \param name string form of the cause
01076  * Returns the cause code
01077  */
01078 int ast_str2cause(const char *name) attribute_pure;
01079 
01080 /*! Gives the string form of a given channel state */
01081 /*! 
01082  * \param ast_channel_state state to get the name of
01083  * Give a name to a state 
01084  * Returns the text form of the binary state given
01085  */
01086 char *ast_state2str(enum ast_channel_state);
01087 
01088 /*! Gives the string form of a given transfer capability */
01089 /*!
01090  * \param transfercapability transfercapabilty to get the name of
01091  * Give a name to a transfercapbility
01092  * See above
01093  * Returns the text form of the binary transfer capbility
01094  */
01095 char *ast_transfercapability2str(int transfercapability) attribute_const;
01096 
01097 /* Options: Some low-level drivers may implement "options" allowing fine tuning of the
01098    low level channel.  See frame.h for options.  Note that many channel drivers may support
01099    none or a subset of those features, and you should not count on this if you want your
01100    asterisk application to be portable.  They're mainly useful for tweaking performance */
01101 
01102 /*! Sets an option on a channel */
01103 /*! 
01104  * \param channel channel to set options on
01105  * \param option option to change
01106  * \param data data specific to option
01107  * \param datalen length of the data
01108  * \param block blocking or not
01109  * Set an option on a channel (see frame.h), optionally blocking awaiting the reply 
01110  * Returns 0 on success and -1 on failure
01111  */
01112 int ast_channel_setoption(struct ast_channel *channel, int option, void *data, int datalen, int block);
01113 
01114 /*! Pick the best codec  */
01115 /* Choose the best codec...  Uhhh...   Yah. */
01116 int ast_best_codec(int fmts);
01117 
01118 
01119 /*! Checks the value of an option */
01120 /*! 
01121  * Query the value of an option, optionally blocking until a reply is received
01122  * Works similarly to setoption except only reads the options.
01123  */
01124 struct ast_frame *ast_channel_queryoption(struct ast_channel *channel, int option, void *data, int *datalen, int block);
01125 
01126 /*! Checks for HTML support on a channel */
01127 /*! Returns 0 if channel does not support HTML or non-zero if it does */
01128 int ast_channel_supports_html(struct ast_channel *channel);
01129 
01130 /*! Sends HTML on given channel */
01131 /*! Send HTML or URL on link.  Returns 0 on success or -1 on failure */
01132 int ast_channel_sendhtml(struct ast_channel *channel, int subclass, const char *data, int datalen);
01133 
01134 /*! Sends a URL on a given link */
01135 /*! Send URL on link.  Returns 0 on success or -1 on failure */
01136 int ast_channel_sendurl(struct ast_channel *channel, const char *url);
01137 
01138 /*! Defers DTMF */
01139 /*! Defer DTMF so that you only read things like hangups and audio.  Returns
01140    non-zero if channel was already DTMF-deferred or 0 if channel is just now
01141    being DTMF-deferred */
01142 int ast_channel_defer_dtmf(struct ast_channel *chan);
01143 
01144 /*! Undeos a defer */
01145 /*! Undo defer.  ast_read will return any dtmf characters that were queued */
01146 void ast_channel_undefer_dtmf(struct ast_channel *chan);
01147 
01148 /*! Initiate system shutdown -- prevents new channels from being allocated.
01149     If "hangup" is non-zero, all existing channels will receive soft
01150      hangups */
01151 void ast_begin_shutdown(int hangup);
01152 
01153 /*! Cancels an existing shutdown and returns to normal operation */
01154 void ast_cancel_shutdown(void);
01155 
01156 /*! Returns number of active/allocated channels */
01157 int ast_active_channels(void);
01158 
01159 /*! Returns non-zero if Asterisk is being shut down */
01160 int ast_shutting_down(void);
01161 
01162 /*! Activate a given generator */
01163 int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params);
01164 
01165 /*! Deactive an active generator */
01166 void ast_deactivate_generator(struct ast_channel *chan);
01167 
01168 /*!
01169  * \note The channel does not need to be locked before calling this function.
01170  */
01171 void ast_set_callerid(struct ast_channel *chan, const char *cidnum, const char *cidname, const char *ani);
01172 
01173 
01174 /*! return a mallocd string with the result of sprintf of the fmt and following args */
01175 char __attribute__((format(printf, 1, 2))) *ast_safe_string_alloc(const char *fmt, ...);
01176 
01177 
01178 /*! Start a tone going */
01179 int ast_tonepair_start(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01180 /*! Stop a tone from playing */
01181 void ast_tonepair_stop(struct ast_channel *chan);
01182 /*! Play a tone pair for a given amount of time */
01183 int ast_tonepair(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01184 
01185 /*!
01186  * \brief Automatically service a channel for us... 
01187  *
01188  * \retval 0 success
01189  * \retval -1 failure, or the channel is already being autoserviced
01190  */
01191 int ast_autoservice_start(struct ast_channel *chan);
01192 
01193 /*! 
01194  * \brief Stop servicing a channel for us...  
01195  *
01196  * \note if chan is locked prior to calling ast_autoservice_stop, it
01197  * is likely that there will be a deadlock between the thread that calls
01198  * ast_autoservice_stop and the autoservice thread. It is important
01199  * that chan is not locked prior to this call
01200  *
01201  * \retval 0 success
01202  * \retval -1 error, or the channel has been hungup 
01203  */
01204 int ast_autoservice_stop(struct ast_channel *chan);
01205 
01206 /* If built with DAHDI optimizations, force a scheduled expiration on the
01207    timer fd, at which point we call the callback function / data */
01208 int ast_settimeout(struct ast_channel *c, int samples, int (*func)(const void *data), void *data);
01209 
01210 /*!   \brief Transfer a channel (if supported).  Returns -1 on error, 0 if not supported
01211    and 1 if supported and requested 
01212    \param chan current channel
01213    \param dest destination extension for transfer
01214 */
01215 int ast_transfer(struct ast_channel *chan, char *dest);
01216 
01217 /*!   \brief  Start masquerading a channel
01218    XXX This is a seriously wacked out operation.  We're essentially putting the guts of
01219            the clone channel into the original channel.  Start by killing off the original
01220            channel's backend.   I'm not sure we're going to keep this function, because
01221            while the features are nice, the cost is very high in terms of pure nastiness. XXX
01222    \param chan    Channel to masquerade
01223 */
01224 int ast_do_masquerade(struct ast_channel *chan);
01225 
01226 /*!   \brief Find bridged channel 
01227    \param chan Current channel
01228 */
01229 struct ast_channel *ast_bridged_channel(struct ast_channel *chan);
01230 
01231 /*!
01232   \brief Inherits channel variable from parent to child channel
01233   \param parent Parent channel
01234   \param child Child channel
01235 
01236   Scans all channel variables in the parent channel, looking for those
01237   that should be copied into the child channel.
01238   Variables whose names begin with a single '_' are copied into the
01239   child channel with the prefix removed.
01240   Variables whose names begin with '__' are copied into the child
01241   channel with their names unchanged.
01242 */
01243 void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child);
01244 
01245 /*!
01246   \brief adds a list of channel variables to a channel
01247   \param chan the channel
01248   \param vars a linked list of variables
01249 
01250   Variable names can be for a regular channel variable or a dialplan function
01251   that has the ability to be written to.
01252 */
01253 void ast_set_variables(struct ast_channel *chan, struct ast_variable *vars);
01254 
01255 /*!
01256   \brief An opaque 'object' structure use by silence generators on channels.
01257  */
01258 struct ast_silence_generator;
01259 
01260 /*!
01261   \brief Starts a silence generator on the given channel.
01262   \param chan The channel to generate silence on
01263   \return An ast_silence_generator pointer, or NULL if an error occurs
01264 
01265   This function will cause SLINEAR silence to be generated on the supplied
01266   channel until it is disabled; if the channel cannot be put into SLINEAR
01267   mode then the function will fail.
01268 
01269   The pointer returned by this function must be preserved and passed to
01270   ast_channel_stop_silence_generator when you wish to stop the silence
01271   generation.
01272  */
01273 struct ast_silence_generator *ast_channel_start_silence_generator(struct ast_channel *chan);
01274 
01275 /*!
01276   \brief Stops a previously-started silence generator on the given channel.
01277   \param chan The channel to operate on
01278   \param state The ast_silence_generator pointer return by a previous call to
01279   ast_channel_start_silence_generator.
01280   \return nothing
01281 
01282   This function will stop the operating silence generator and return the channel
01283   to its previous write format.
01284  */
01285 void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state);
01286 
01287 /*!
01288   \brief Check if the channel can run in internal timing mode.
01289   \param chan The channel to check
01290   \return boolean
01291 
01292   This function will return 1 if internal timing is enabled and the timing
01293   device is available.
01294  */
01295 int ast_internal_timing_enabled(struct ast_channel *chan);
01296 
01297 /* Misc. functions below */
01298 
01299 /*! \brief if fd is a valid descriptor, set *pfd with the descriptor
01300  * \return Return 1 (not -1!) if added, 0 otherwise (so we can add the
01301  * return value to the index into the array)
01302  */
01303 static inline int ast_add_fd(struct pollfd *pfd, int fd)
01304 {
01305    pfd->fd = fd;
01306    pfd->events = POLLIN | POLLPRI;
01307    return fd >= 0;
01308 }
01309 
01310 /*! \brief Helper function for migrating select to poll */
01311 static inline int ast_fdisset(struct pollfd *pfds, int fd, int max, int *start)
01312 {
01313    int x;
01314    int dummy=0;
01315 
01316    if (fd < 0)
01317       return 0;
01318    if (!start)
01319       start = &dummy;
01320    for (x = *start; x<max; x++)
01321       if (pfds[x].fd == fd) {
01322          if (x == *start)
01323             (*start)++;
01324          return pfds[x].revents;
01325       }
01326    return 0;
01327 }
01328 
01329 #ifndef HAVE_TIMERSUB
01330 static inline void timersub(struct timeval *tvend, struct timeval *tvstart, struct timeval *tvdiff)
01331 {
01332    tvdiff->tv_sec = tvend->tv_sec - tvstart->tv_sec;
01333    tvdiff->tv_usec = tvend->tv_usec - tvstart->tv_usec;
01334    if (tvdiff->tv_usec < 0) {
01335       tvdiff->tv_sec --;
01336       tvdiff->tv_usec += 1000000;
01337    }
01338 
01339 }
01340 #endif
01341 
01342 /*! \brief Waits for activity on a group of channels 
01343  * \param nfds the maximum number of file descriptors in the sets
01344  * \param rfds file descriptors to check for read availability
01345  * \param wfds file descriptors to check for write availability
01346  * \param efds file descriptors to check for exceptions (OOB data)
01347  * \param tvp timeout while waiting for events
01348  * This is the same as a standard select(), except it guarantees the
01349  * behaviour where the passed struct timeval is updated with how much
01350  * time was not slept while waiting for the specified events
01351  */
01352 static inline int ast_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *tvp)
01353 {
01354 #ifdef __linux__
01355    return select(nfds, rfds, wfds, efds, tvp);
01356 #else
01357    if (tvp) {
01358       struct timeval tv, tvstart, tvend, tvlen;
01359       int res;
01360 
01361       tv = *tvp;
01362       gettimeofday(&tvstart, NULL);
01363       res = select(nfds, rfds, wfds, efds, tvp);
01364       gettimeofday(&tvend, NULL);
01365       timersub(&tvend, &tvstart, &tvlen);
01366       timersub(&tv, &tvlen, tvp);
01367       if (tvp->tv_sec < 0 || (tvp->tv_sec == 0 && tvp->tv_usec < 0)) {
01368          tvp->tv_sec = 0;
01369          tvp->tv_usec = 0;
01370       }
01371       return res;
01372    }
01373    else
01374       return select(nfds, rfds, wfds, efds, NULL);
01375 #endif
01376 }
01377 
01378 #define CHECK_BLOCKING(c) do {    \
01379    if (ast_test_flag(c, AST_FLAG_BLOCKING)) {\
01380       if (option_debug) \
01381          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); \
01382    } else { \
01383       (c)->blocker = pthread_self(); \
01384       (c)->blockproc = __PRETTY_FUNCTION__; \
01385       ast_set_flag(c, AST_FLAG_BLOCKING); \
01386    } } while (0)
01387 
01388 ast_group_t ast_get_group(const char *s);
01389 
01390 /*! \brief print call- and pickup groups into buffer */
01391 char *ast_print_group(char *buf, int buflen, ast_group_t group);
01392 
01393 /*! \brief Convert enum channelreloadreason to text string for manager event
01394    \param reason  Enum channelreloadreason - reason for reload (manager, cli, start etc)
01395 */
01396 const char *channelreloadreason2txt(enum channelreloadreason reason);
01397 
01398 /*! \brief return an ast_variable list of channeltypes */
01399 struct ast_variable *ast_channeltype_list(void);
01400 
01401 /*!
01402   \brief Begin 'whispering' onto a channel
01403   \param chan The channel to whisper onto
01404   \return 0 for success, non-zero for failure
01405 
01406   This function will add a whisper buffer onto a channel and set a flag
01407   causing writes to the channel to reduce the volume level of the written
01408   audio samples, and then to mix in audio from the whisper buffer if it
01409   is available.
01410 
01411   Note: This function performs no locking; you must hold the channel's lock before
01412   calling this function.
01413  */
01414 int ast_channel_whisper_start(struct ast_channel *chan);
01415 
01416 /*!
01417   \brief Feed an audio frame into the whisper buffer on a channel
01418   \param chan The channel to whisper onto
01419   \param f The frame to to whisper onto chan
01420   \return 0 for success, non-zero for failure
01421  */
01422 int ast_channel_whisper_feed(struct ast_channel *chan, struct ast_frame *f);
01423 
01424 /*!
01425   \brief Stop 'whispering' onto a channel
01426   \param chan The channel to whisper onto
01427   \return 0 for success, non-zero for failure
01428 
01429   Note: This function performs no locking; you must hold the channel's lock before
01430   calling this function.
01431  */
01432 void ast_channel_whisper_stop(struct ast_channel *chan);
01433 
01434 
01435 
01436 /*!
01437   \brief return an english explanation of the code returned thru __ast_request_and_dial's 'outstate' argument
01438   \param reason  The integer argument, usually taken from AST_CONTROL_ macros
01439   \return char pointer explaining the code
01440  */
01441 char *ast_channel_reason2str(int reason);
01442 
01443 
01444 #if defined(__cplusplus) || defined(c_plusplus)
01445 }
01446 #endif
01447 
01448 #endif /* _ASTERISK_CHANNEL_H */

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