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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, 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 dtmfq[AST_MAX_EXTENSION];         /*!< Any/all queued DTMF characters */
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 ind_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 };
00514 
00515 /*! \brief ast_bridge_config flags */
00516 enum {
00517    AST_FEATURE_PLAY_WARNING = (1 << 0),
00518    AST_FEATURE_REDIRECT =     (1 << 1),
00519    AST_FEATURE_DISCONNECT =   (1 << 2),
00520    AST_FEATURE_ATXFER =       (1 << 3),
00521    AST_FEATURE_AUTOMON =      (1 << 4),
00522    AST_FEATURE_PARKCALL =     (1 << 5),
00523 };
00524 
00525 struct ast_bridge_config {
00526    struct ast_flags features_caller;
00527    struct ast_flags features_callee;
00528    struct timeval start_time;
00529    long feature_timer;
00530    long timelimit;
00531    long play_warning;
00532    long warning_freq;
00533    const char *warning_sound;
00534    const char *end_sound;
00535    const char *start_sound;
00536    int firstpass;
00537    unsigned int flags;
00538 };
00539 
00540 struct chanmon;
00541 
00542 #define LOAD_OH(oh) {   \
00543    oh.context = context; \
00544    oh.exten = exten; \
00545    oh.priority = priority; \
00546    oh.cid_num = cid_num; \
00547    oh.cid_name = cid_name; \
00548    oh.account = account; \
00549    oh.vars = vars; \
00550    oh.parent_channel = NULL; \
00551 } 
00552 
00553 struct outgoing_helper {
00554    const char *context;
00555    const char *exten;
00556    int priority;
00557    const char *cid_num;
00558    const char *cid_name;
00559    const char *account;
00560    struct ast_variable *vars;
00561    struct ast_channel *parent_channel;
00562 };
00563 
00564 enum {
00565    AST_CDR_TRANSFER =   (1 << 0),
00566    AST_CDR_FORWARD =    (1 << 1),
00567    AST_CDR_CALLWAIT =   (1 << 2),
00568    AST_CDR_CONFERENCE = (1 << 3),
00569 };
00570 
00571 enum {
00572    /*! Soft hangup by device */
00573    AST_SOFTHANGUP_DEV =       (1 << 0),
00574    /*! Soft hangup for async goto */
00575    AST_SOFTHANGUP_ASYNCGOTO = (1 << 1),
00576    AST_SOFTHANGUP_SHUTDOWN =  (1 << 2),
00577    AST_SOFTHANGUP_TIMEOUT =   (1 << 3),
00578    AST_SOFTHANGUP_APPUNLOAD = (1 << 4),
00579    AST_SOFTHANGUP_EXPLICIT =  (1 << 5),
00580    AST_SOFTHANGUP_UNBRIDGE =  (1 << 6),
00581 };
00582 
00583 
00584 /*! \brief Channel reload reasons for manager events at load or reload of configuration */
00585 enum channelreloadreason {
00586    CHANNEL_MODULE_LOAD,
00587    CHANNEL_MODULE_RELOAD,
00588    CHANNEL_CLI_RELOAD,
00589    CHANNEL_MANAGER_RELOAD,
00590 };
00591 
00592 /*! \brief Create a channel datastore structure */
00593 struct ast_datastore *ast_channel_datastore_alloc(const struct ast_datastore_info *info, char *uid);
00594 
00595 /*! \brief Free a channel datastore structure */
00596 int ast_channel_datastore_free(struct ast_datastore *datastore);
00597 
00598 /*! \brief Inherit datastores from a parent to a child. */
00599 int ast_channel_datastore_inherit(struct ast_channel *from, struct ast_channel *to);
00600 
00601 /*! \brief Add a datastore to a channel */
00602 int ast_channel_datastore_add(struct ast_channel *chan, struct ast_datastore *datastore);
00603 
00604 /*! \brief Remove a datastore from a channel */
00605 int ast_channel_datastore_remove(struct ast_channel *chan, struct ast_datastore *datastore);
00606 
00607 /*! \brief Find a datastore on a channel */
00608 struct ast_datastore *ast_channel_datastore_find(struct ast_channel *chan, const struct ast_datastore_info *info, char *uid);
00609 
00610 /*! \brief Change the state of a channel */
00611 int ast_setstate(struct ast_channel *chan, enum ast_channel_state);
00612 
00613 /*! \brief Create a channel structure 
00614     \return Returns NULL on failure to allocate.
00615    \note New channels are 
00616    by default set to the "default" context and
00617    extension "s"
00618  */
00619 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, ...);
00620 
00621 /*! \brief Queue an outgoing frame */
00622 int ast_queue_frame(struct ast_channel *chan, struct ast_frame *f);
00623 
00624 /*! \brief Queue a hangup frame */
00625 int ast_queue_hangup(struct ast_channel *chan);
00626 
00627 /*!
00628   \brief Queue a control frame with payload
00629   \param chan channel to queue frame onto
00630   \param control type of control frame
00631   \return zero on success, non-zero on failure
00632 */
00633 int ast_queue_control(struct ast_channel *chan, enum ast_control_frame_type control);
00634 
00635 /*!
00636   \brief Queue a control frame with payload
00637   \param chan channel to queue frame onto
00638   \param control type of control frame
00639   \param data pointer to payload data to be included in frame
00640   \param datalen number of bytes of payload data
00641   \return zero on success, non-zero on failure
00642 
00643   The supplied payload data is copied into the frame, so the caller's copy
00644   is not modified nor freed, and the resulting frame will retain a copy of
00645   the data even if the caller frees their local copy.
00646 
00647   \note This method should be treated as a 'network transport'; in other
00648   words, your frames may be transferred across an IAX2 channel to another
00649   system, which may be a different endianness than yours. Because of this,
00650   you should ensure that either your frames will never be expected to work
00651   across systems, or that you always put your payload data into 'network byte
00652   order' before calling this function.
00653 */
00654 int ast_queue_control_data(struct ast_channel *chan, enum ast_control_frame_type control,
00655             const void *data, size_t datalen);
00656 
00657 /*! \brief Change channel name */
00658 void ast_change_name(struct ast_channel *chan, char *newname);
00659 
00660 /*! \brief Free a channel structure */
00661 void  ast_channel_free(struct ast_channel *);
00662 
00663 /*! \brief Requests a channel 
00664  * \param type type of channel to request
00665  * \param format requested channel format (codec)
00666  * \param data data to pass to the channel requester
00667  * \param status status
00668  * Request a channel of a given type, with data as optional information used 
00669  * by the low level module
00670  * \return Returns an ast_channel on success, NULL on failure.
00671  */
00672 struct ast_channel *ast_request(const char *type, int format, void *data, int *status);
00673 
00674 /*!
00675  * \brief Request a channel of a given type, with data as optional information used 
00676  * by the low level module and attempt to place a call on it
00677  * \param type type of channel to request
00678  * \param format requested channel format
00679  * \param data data to pass to the channel requester
00680  * \param timeout maximum amount of time to wait for an answer
00681  * \param reason why unsuccessful (if unsuceessful)
00682  * \param cidnum Caller-ID Number
00683  * \param cidname Caller-ID Name
00684  * \return Returns an ast_channel on success or no answer, NULL on failure.  Check the value of chan->_state
00685  * to know if the call was answered or not.
00686  */
00687 struct ast_channel *ast_request_and_dial(const char *type, int format, void *data, int timeout, int *reason, const char *cidnum, const char *cidname);
00688 
00689 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);
00690 
00691 /*!\brief Register a channel technology (a new channel driver)
00692  * Called by a channel module to register the kind of channels it supports.
00693  * \param tech Structure defining channel technology or "type"
00694  * \return Returns 0 on success, -1 on failure.
00695  */
00696 int ast_channel_register(const struct ast_channel_tech *tech);
00697 
00698 /*! \brief Unregister a channel technology 
00699  * \param tech Structure defining channel technology or "type" that was previously registered
00700  * \return No return value.
00701  */
00702 void ast_channel_unregister(const struct ast_channel_tech *tech);
00703 
00704 /*! \brief Get a channel technology structure by name
00705  * \param name name of technology to find
00706  * \return a pointer to the structure, or NULL if no matching technology found
00707  */
00708 const struct ast_channel_tech *ast_get_channel_tech(const char *name);
00709 
00710 /*! \brief Hang up a channel  
00711  * \note This function performs a hard hangup on a channel.  Unlike the soft-hangup, this function
00712  * performs all stream stopping, etc, on the channel that needs to end.
00713  * chan is no longer valid after this call.
00714  * \param chan channel to hang up
00715  * \return Returns 0 on success, -1 on failure.
00716  */
00717 int ast_hangup(struct ast_channel *chan);
00718 
00719 /*! \brief Softly hangup up a channel 
00720  * \param chan channel to be soft-hung-up
00721  * Call the protocol layer, but don't destroy the channel structure (use this if you are trying to
00722  * safely hangup a channel managed by another thread.
00723  * \param cause   Ast hangupcause for hangup
00724  * \return Returns 0 regardless
00725  */
00726 int ast_softhangup(struct ast_channel *chan, int cause);
00727 
00728 /*! \brief Softly hangup up a channel (no channel lock) 
00729  * \param chan channel to be soft-hung-up
00730  * \param cause   Ast hangupcause for hangup (see cause.h) */
00731 int ast_softhangup_nolock(struct ast_channel *chan, int cause);
00732 
00733 /*! \brief Check to see if a channel is needing hang up 
00734  * \param chan channel on which to check for hang up
00735  * This function determines if the channel is being requested to be hung up.
00736  * \return Returns 0 if not, or 1 if hang up is requested (including time-out).
00737  */
00738 int ast_check_hangup(struct ast_channel *chan);
00739 
00740 /*! \brief Compare a offset with the settings of when to hang a channel up 
00741  * \param chan channel on which to check for hang up
00742  * \param offset offset in seconds from current time
00743  * \return 1, 0, or -1
00744  * This function compares a offset from current time with the absolute time 
00745  * out on a channel (when to hang up). If the absolute time out on a channel
00746  * is earlier than current time plus the offset, it returns 1, if the two
00747  * time values are equal, it return 0, otherwise, it retturn -1.
00748  */
00749 int ast_channel_cmpwhentohangup(struct ast_channel *chan, time_t offset);
00750 
00751 /*! \brief Set when to hang a channel up 
00752  * \param chan channel on which to check for hang up
00753  * \param offset offset in seconds from current time of when to hang up
00754  * This function sets the absolute time out on a channel (when to hang up).
00755  */
00756 void ast_channel_setwhentohangup(struct ast_channel *chan, time_t offset);
00757 
00758 /*! \brief Answer a ringing call 
00759  * \param chan channel to answer
00760  * This function answers a channel and handles all necessary call
00761  * setup functions.
00762  * \return Returns 0 on success, -1 on failure
00763  */
00764 int ast_answer(struct ast_channel *chan);
00765 
00766 /*! \brief Make a call 
00767  * \param chan which channel to make the call on
00768  * \param addr destination of the call
00769  * \param timeout time to wait on for connect
00770  * Place a call, take no longer than timeout ms. 
00771    \return Returns -1 on failure, 0 on not enough time 
00772    (does not automatically stop ringing), and  
00773    the number of seconds the connect took otherwise.
00774    */
00775 int ast_call(struct ast_channel *chan, char *addr, int timeout);
00776 
00777 /*! \brief Indicates condition of channel 
00778  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
00779  * \param chan channel to change the indication
00780  * \param condition which condition to indicate on the channel
00781  * \return Returns 0 on success, -1 on failure
00782  */
00783 int ast_indicate(struct ast_channel *chan, int condition);
00784 
00785 /*! \brief Indicates condition of channel, with payload
00786  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
00787  * \param chan channel to change the indication
00788  * \param condition which condition to indicate on the channel
00789  * \param data pointer to payload data
00790  * \param datalen size of payload data
00791  * \return Returns 0 on success, -1 on failure
00792  */
00793 int ast_indicate_data(struct ast_channel *chan, int condition, const void *data, size_t datalen);
00794 
00795 /* Misc stuff ------------------------------------------------ */
00796 
00797 /*! \brief Wait for input on a channel 
00798  * \param chan channel to wait on
00799  * \param ms length of time to wait on the channel
00800  * Wait for input on a channel for a given # of milliseconds (<0 for indefinite). 
00801   \return Returns < 0 on  failure, 0 if nothing ever arrived, and the # of ms remaining otherwise */
00802 int ast_waitfor(struct ast_channel *chan, int ms);
00803 
00804 /*! \brief Wait for a specied amount of time, looking for hangups 
00805  * \param chan channel to wait for
00806  * \param ms length of time in milliseconds to sleep
00807  * Waits for a specified amount of time, servicing the channel as required.
00808  * \return returns -1 on hangup, otherwise 0.
00809  */
00810 int ast_safe_sleep(struct ast_channel *chan, int ms);
00811 
00812 /*! \brief Wait for a specied amount of time, looking for hangups and a condition argument 
00813  * \param chan channel to wait for
00814  * \param ms length of time in milliseconds to sleep
00815  * \param cond a function pointer for testing continue condition
00816  * \param data argument to be passed to the condition test function
00817  * \return returns -1 on hangup, otherwise 0.
00818  * Waits for a specified amount of time, servicing the channel as required. If cond
00819  * returns 0, this function returns.
00820  */
00821 int ast_safe_sleep_conditional(struct ast_channel *chan, int ms, int (*cond)(void*), void *data );
00822 
00823 /*! \brief Waits for activity on a group of channels 
00824  * \param chan an array of pointers to channels
00825  * \param n number of channels that are to be waited upon
00826  * \param fds an array of fds to wait upon
00827  * \param nfds the number of fds to wait upon
00828  * \param exception exception flag
00829  * \param outfd fd that had activity on it
00830  * \param ms how long the wait was
00831  * Big momma function here.  Wait for activity on any of the n channels, or any of the nfds
00832    file descriptors.
00833    \return Returns the channel with activity, or NULL on error or if an FD
00834    came first.  If the FD came first, it will be returned in outfd, otherwise, outfd
00835    will be -1 */
00836 struct ast_channel *ast_waitfor_nandfds(struct ast_channel **chan, int n, int *fds, int nfds, int *exception, int *outfd, int *ms);
00837 
00838 /*! \brief Waits for input on a group of channels
00839    Wait for input on an array of channels for a given # of milliseconds. 
00840    \return Return channel with activity, or NULL if none has activity.  
00841    \param chan an array of pointers to channels
00842    \param n number of channels that are to be waited upon
00843    \param ms time "ms" is modified in-place, if applicable */
00844 struct ast_channel *ast_waitfor_n(struct ast_channel **chan, int n, int *ms);
00845 
00846 /*! \brief Waits for input on an fd
00847    This version works on fd's only.  Be careful with it. */
00848 int ast_waitfor_n_fd(int *fds, int n, int *ms, int *exception);
00849 
00850 
00851 /*! \brief Reads a frame
00852  * \param chan channel to read a frame from
00853    Read a frame.  
00854    \return Returns a frame, or NULL on error.  If it returns NULL, you
00855       best just stop reading frames and assume the channel has been
00856       disconnected. */
00857 struct ast_frame *ast_read(struct ast_channel *chan);
00858 
00859 /*! \brief Reads a frame, returning AST_FRAME_NULL frame if audio. 
00860  * Read a frame. 
00861    \param chan channel to read a frame from
00862    \return  Returns a frame, or NULL on error.  If it returns NULL, you
00863       best just stop reading frames and assume the channel has been
00864       disconnected.  
00865    \note Audio is replaced with AST_FRAME_NULL to avoid 
00866    transcode when the resulting audio is not necessary. */
00867 struct ast_frame *ast_read_noaudio(struct ast_channel *chan);
00868 
00869 /*! \brief Write a frame to a channel 
00870  * This function writes the given frame to the indicated channel.
00871  * \param chan destination channel of the frame
00872  * \param frame frame that will be written
00873  * \return It returns 0 on success, -1 on failure.
00874  */
00875 int ast_write(struct ast_channel *chan, struct ast_frame *frame);
00876 
00877 /*! \brief Write video frame to a channel 
00878  * This function writes the given frame to the indicated channel.
00879  * \param chan destination channel of the frame
00880  * \param frame frame that will be written
00881  * \return It returns 1 on success, 0 if not implemented, and -1 on failure.
00882  */
00883 int ast_write_video(struct ast_channel *chan, struct ast_frame *frame);
00884 
00885 /*! \brief Send empty audio to prime a channel driver */
00886 int ast_prod(struct ast_channel *chan);
00887 
00888 /*! \brief Sets read format on channel chan
00889  * Set read format for channel to whichever component of "format" is best. 
00890  * \param chan channel to change
00891  * \param format format to change to
00892  * \return Returns 0 on success, -1 on failure
00893  */
00894 int ast_set_read_format(struct ast_channel *chan, int format);
00895 
00896 /*! \brief Sets write format on channel chan
00897  * Set write format for channel to whichever compoent of "format" is best. 
00898  * \param chan channel to change
00899  * \param format new format for writing
00900  * \return Returns 0 on success, -1 on failure
00901  */
00902 int ast_set_write_format(struct ast_channel *chan, int format);
00903 
00904 /*! \brief Sends text to a channel 
00905  * Write text to a display on a channel
00906  * \param chan channel to act upon
00907  * \param text string of text to send on the channel
00908  * \return Returns 0 on success, -1 on failure
00909  */
00910 int ast_sendtext(struct ast_channel *chan, const char *text);
00911 
00912 /*! \brief Receives a text character from a channel
00913  * \param chan channel to act upon
00914  * \param timeout timeout in milliseconds (0 for infinite wait)
00915  * Read a char of text from a channel
00916  * Returns 0 on success, -1 on failure
00917  */
00918 int ast_recvchar(struct ast_channel *chan, int timeout);
00919 
00920 /*! \brief Send a DTMF digit to a channel
00921  * Send a DTMF digit to a channel.
00922  * \param chan channel to act upon
00923  * \param digit the DTMF digit to send, encoded in ASCII
00924  * \return Returns 0 on success, -1 on failure
00925  */
00926 int ast_senddigit(struct ast_channel *chan, char digit);
00927 
00928 int ast_senddigit_begin(struct ast_channel *chan, char digit);
00929 int ast_senddigit_end(struct ast_channel *chan, char digit, unsigned int duration);
00930 
00931 /*! \brief Receives a text string from a channel
00932  * Read a string of text from a channel
00933  * \param chan channel to act upon
00934  * \param timeout timeout in milliseconds (0 for infinite wait)
00935  * \return the received text, or NULL to signify failure.
00936  */
00937 char *ast_recvtext(struct ast_channel *chan, int timeout);
00938 
00939 /*! \brief Browse channels in use
00940  * Browse the channels currently in use 
00941  * \param prev where you want to start in the channel list
00942  * \return Returns the next channel in the list, NULL on end.
00943  *    If it returns a channel, that channel *has been locked*!
00944  */
00945 struct ast_channel *ast_channel_walk_locked(const struct ast_channel *prev);
00946 
00947 /*! \brief Get channel by name (locks channel) */
00948 struct ast_channel *ast_get_channel_by_name_locked(const char *chan);
00949 
00950 /*! \brief Get channel by name prefix (locks channel) */
00951 struct ast_channel *ast_get_channel_by_name_prefix_locked(const char *name, const int namelen);
00952 
00953 /*! \brief Get channel by name prefix (locks channel) */
00954 struct ast_channel *ast_walk_channel_by_name_prefix_locked(const struct ast_channel *chan, const char *name, const int namelen);
00955 
00956 /*! \brief Get channel by exten (and optionally context) and lock it */
00957 struct ast_channel *ast_get_channel_by_exten_locked(const char *exten, const char *context);
00958 
00959 /*! \brief Get next channel by exten (and optionally context) and lock it */
00960 struct ast_channel *ast_walk_channel_by_exten_locked(const struct ast_channel *chan, const char *exten,
00961                        const char *context);
00962 
00963 /*! ! \brief Waits for a digit
00964  * \param c channel to wait for a digit on
00965  * \param ms how many milliseconds to wait
00966  * \return Returns <0 on error, 0 on no entry, and the digit on success. */
00967 int ast_waitfordigit(struct ast_channel *c, int ms);
00968 
00969 /*! \brief Wait for a digit
00970  Same as ast_waitfordigit() with audio fd for outputting read audio and ctrlfd to monitor for reading. 
00971  * \param c channel to wait for a digit on
00972  * \param ms how many milliseconds to wait
00973  * \param audiofd audio file descriptor to write to if audio frames are received
00974  * \param ctrlfd control file descriptor to monitor for reading
00975  * \return Returns 1 if ctrlfd becomes available */
00976 int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int ctrlfd);
00977 
00978 /*! Reads multiple digits 
00979  * \param c channel to read from
00980  * \param s string to read in to.  Must be at least the size of your length
00981  * \param len how many digits to read (maximum)
00982  * \param timeout how long to timeout between digits
00983  * \param rtimeout timeout to wait on the first digit
00984  * \param enders digits to end the string
00985  * Read in a digit string "s", max length "len", maximum timeout between 
00986    digits "timeout" (-1 for none), terminated by anything in "enders".  Give them rtimeout
00987    for the first digit.  Returns 0 on normal return, or 1 on a timeout.  In the case of
00988    a timeout, any digits that were read before the timeout will still be available in s.  
00989    RETURNS 2 in full version when ctrlfd is available, NOT 1*/
00990 int ast_readstring(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders);
00991 int ast_readstring_full(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders, int audiofd, int ctrlfd);
00992 
00993 /*! \brief Report DTMF on channel 0 */
00994 #define AST_BRIDGE_DTMF_CHANNEL_0      (1 << 0)    
00995 /*! \brief Report DTMF on channel 1 */
00996 #define AST_BRIDGE_DTMF_CHANNEL_1      (1 << 1)    
00997 /*! \brief Return all voice frames on channel 0 */
00998 #define AST_BRIDGE_REC_CHANNEL_0    (1 << 2)    
00999 /*! \brief Return all voice frames on channel 1 */
01000 #define AST_BRIDGE_REC_CHANNEL_1    (1 << 3)    
01001 /*! \brief Ignore all signal frames except NULL */
01002 #define AST_BRIDGE_IGNORE_SIGS         (1 << 4)    
01003 
01004 
01005 /*! \brief Makes two channel formats compatible 
01006  * \param c0 first channel to make compatible
01007  * \param c1 other channel to make compatible
01008  * Set two channels to compatible formats -- call before ast_channel_bridge in general .  
01009  * \return Returns 0 on success and -1 if it could not be done */
01010 int ast_channel_make_compatible(struct ast_channel *c0, struct ast_channel *c1);
01011 
01012 /*! Bridge two channels together 
01013  * \param c0 first channel to bridge
01014  * \param c1 second channel to bridge
01015  * \param config config for the channels
01016  * \param fo destination frame(?)
01017  * \param rc destination channel(?)
01018  * Bridge two channels (c0 and c1) together.  If an important frame occurs, we return that frame in
01019    *rf (remember, it could be NULL) and which channel (0 or 1) in rc */
01020 /* int ast_channel_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc); */
01021 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);
01022 
01023 /*! \brief Weird function made for call transfers
01024  * \param original channel to make a copy of
01025  * \param clone copy of the original channel
01026  * This is a very strange and freaky function used primarily for transfer.  Suppose that
01027    "original" and "clone" are two channels in random situations.  This function takes
01028    the guts out of "clone" and puts them into the "original" channel, then alerts the
01029    channel driver of the change, asking it to fixup any private information (like the
01030    p->owner pointer) that is affected by the change.  The physical layer of the original
01031    channel is hung up.  */
01032 int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clone);
01033 
01034 /*! Gives the string form of a given cause code */
01035 /*! 
01036  * \param state cause to get the description of
01037  * Give a name to a cause code
01038  * Returns the text form of the binary cause code given
01039  */
01040 const char *ast_cause2str(int state) attribute_pure;
01041 
01042 /*! Convert the string form of a cause code to a number */
01043 /*! 
01044  * \param name string form of the cause
01045  * Returns the cause code
01046  */
01047 int ast_str2cause(const char *name) attribute_pure;
01048 
01049 /*! Gives the string form of a given channel state */
01050 /*! 
01051  * \param ast_channel_state state to get the name of
01052  * Give a name to a state 
01053  * Returns the text form of the binary state given
01054  */
01055 char *ast_state2str(enum ast_channel_state);
01056 
01057 /*! Gives the string form of a given transfer capability */
01058 /*!
01059  * \param transfercapability transfercapabilty to get the name of
01060  * Give a name to a transfercapbility
01061  * See above
01062  * Returns the text form of the binary transfer capbility
01063  */
01064 char *ast_transfercapability2str(int transfercapability) attribute_const;
01065 
01066 /* Options: Some low-level drivers may implement "options" allowing fine tuning of the
01067    low level channel.  See frame.h for options.  Note that many channel drivers may support
01068    none or a subset of those features, and you should not count on this if you want your
01069    asterisk application to be portable.  They're mainly useful for tweaking performance */
01070 
01071 /*! Sets an option on a channel */
01072 /*! 
01073  * \param channel channel to set options on
01074  * \param option option to change
01075  * \param data data specific to option
01076  * \param datalen length of the data
01077  * \param block blocking or not
01078  * Set an option on a channel (see frame.h), optionally blocking awaiting the reply 
01079  * Returns 0 on success and -1 on failure
01080  */
01081 int ast_channel_setoption(struct ast_channel *channel, int option, void *data, int datalen, int block);
01082 
01083 /*! Pick the best codec  */
01084 /* Choose the best codec...  Uhhh...   Yah. */
01085 int ast_best_codec(int fmts);
01086 
01087 
01088 /*! Checks the value of an option */
01089 /*! 
01090  * Query the value of an option, optionally blocking until a reply is received
01091  * Works similarly to setoption except only reads the options.
01092  */
01093 struct ast_frame *ast_channel_queryoption(struct ast_channel *channel, int option, void *data, int *datalen, int block);
01094 
01095 /*! Checks for HTML support on a channel */
01096 /*! Returns 0 if channel does not support HTML or non-zero if it does */
01097 int ast_channel_supports_html(struct ast_channel *channel);
01098 
01099 /*! Sends HTML on given channel */
01100 /*! Send HTML or URL on link.  Returns 0 on success or -1 on failure */
01101 int ast_channel_sendhtml(struct ast_channel *channel, int subclass, const char *data, int datalen);
01102 
01103 /*! Sends a URL on a given link */
01104 /*! Send URL on link.  Returns 0 on success or -1 on failure */
01105 int ast_channel_sendurl(struct ast_channel *channel, const char *url);
01106 
01107 /*! Defers DTMF */
01108 /*! Defer DTMF so that you only read things like hangups and audio.  Returns
01109    non-zero if channel was already DTMF-deferred or 0 if channel is just now
01110    being DTMF-deferred */
01111 int ast_channel_defer_dtmf(struct ast_channel *chan);
01112 
01113 /*! Undeos a defer */
01114 /*! Undo defer.  ast_read will return any dtmf characters that were queued */
01115 void ast_channel_undefer_dtmf(struct ast_channel *chan);
01116 
01117 /*! Initiate system shutdown -- prevents new channels from being allocated.
01118     If "hangup" is non-zero, all existing channels will receive soft
01119      hangups */
01120 void ast_begin_shutdown(int hangup);
01121 
01122 /*! Cancels an existing shutdown and returns to normal operation */
01123 void ast_cancel_shutdown(void);
01124 
01125 /*! Returns number of active/allocated channels */
01126 int ast_active_channels(void);
01127 
01128 /*! Returns non-zero if Asterisk is being shut down */
01129 int ast_shutting_down(void);
01130 
01131 /*! Activate a given generator */
01132 int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params);
01133 
01134 /*! Deactive an active generator */
01135 void ast_deactivate_generator(struct ast_channel *chan);
01136 
01137 /*!
01138  * \note The channel does not need to be locked before calling this function.
01139  */
01140 void ast_set_callerid(struct ast_channel *chan, const char *cidnum, const char *cidname, const char *ani);
01141 
01142 
01143 /*! return a mallocd string with the result of sprintf of the fmt and following args */
01144 char *ast_safe_string_alloc(const char *fmt, ...);
01145 
01146 
01147 
01148 /*! Start a tone going */
01149 int ast_tonepair_start(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01150 /*! Stop a tone from playing */
01151 void ast_tonepair_stop(struct ast_channel *chan);
01152 /*! Play a tone pair for a given amount of time */
01153 int ast_tonepair(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01154 
01155 /*!
01156  * \brief Automatically service a channel for us... 
01157  *
01158  * \retval 0 success
01159  * \retval -1 failure, or the channel is already being autoserviced
01160  */
01161 int ast_autoservice_start(struct ast_channel *chan);
01162 
01163 /*! 
01164  * \brief Stop servicing a channel for us...  
01165  *
01166  * \retval 0 success
01167  * \retval -1 error, or the channel has been hungup 
01168  */
01169 int ast_autoservice_stop(struct ast_channel *chan);
01170 
01171 /* If built with DAHDI optimizations, force a scheduled expiration on the
01172    timer fd, at which point we call the callback function / data */
01173 int ast_settimeout(struct ast_channel *c, int samples, int (*func)(const void *data), void *data);
01174 
01175 /*!   \brief Transfer a channel (if supported).  Returns -1 on error, 0 if not supported
01176    and 1 if supported and requested 
01177    \param chan current channel
01178    \param dest destination extension for transfer
01179 */
01180 int ast_transfer(struct ast_channel *chan, char *dest);
01181 
01182 /*!   \brief  Start masquerading a channel
01183    XXX This is a seriously wacked out operation.  We're essentially putting the guts of
01184            the clone channel into the original channel.  Start by killing off the original
01185            channel's backend.   I'm not sure we're going to keep this function, because
01186            while the features are nice, the cost is very high in terms of pure nastiness. XXX
01187    \param chan    Channel to masquerade
01188 */
01189 int ast_do_masquerade(struct ast_channel *chan);
01190 
01191 /*!   \brief Find bridged channel 
01192    \param chan Current channel
01193 */
01194 struct ast_channel *ast_bridged_channel(struct ast_channel *chan);
01195 
01196 /*!
01197   \brief Inherits channel variable from parent to child channel
01198   \param parent Parent channel
01199   \param child Child channel
01200 
01201   Scans all channel variables in the parent channel, looking for those
01202   that should be copied into the child channel.
01203   Variables whose names begin with a single '_' are copied into the
01204   child channel with the prefix removed.
01205   Variables whose names begin with '__' are copied into the child
01206   channel with their names unchanged.
01207 */
01208 void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child);
01209 
01210 /*!
01211   \brief adds a list of channel variables to a channel
01212   \param chan the channel
01213   \param vars a linked list of variables
01214 
01215   Variable names can be for a regular channel variable or a dialplan function
01216   that has the ability to be written to.
01217 */
01218 void ast_set_variables(struct ast_channel *chan, struct ast_variable *vars);
01219 
01220 /*!
01221   \brief An opaque 'object' structure use by silence generators on channels.
01222  */
01223 struct ast_silence_generator;
01224 
01225 /*!
01226   \brief Starts a silence generator on the given channel.
01227   \param chan The channel to generate silence on
01228   \return An ast_silence_generator pointer, or NULL if an error occurs
01229 
01230   This function will cause SLINEAR silence to be generated on the supplied
01231   channel until it is disabled; if the channel cannot be put into SLINEAR
01232   mode then the function will fail.
01233 
01234   The pointer returned by this function must be preserved and passed to
01235   ast_channel_stop_silence_generator when you wish to stop the silence
01236   generation.
01237  */
01238 struct ast_silence_generator *ast_channel_start_silence_generator(struct ast_channel *chan);
01239 
01240 /*!
01241   \brief Stops a previously-started silence generator on the given channel.
01242   \param chan The channel to operate on
01243   \param state The ast_silence_generator pointer return by a previous call to
01244   ast_channel_start_silence_generator.
01245   \return nothing
01246 
01247   This function will stop the operating silence generator and return the channel
01248   to its previous write format.
01249  */
01250 void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state);
01251 
01252 /*!
01253   \brief Check if the channel can run in internal timing mode.
01254   \param chan The channel to check
01255   \return boolean
01256 
01257   This function will return 1 if internal timing is enabled and the timing
01258   device is available.
01259  */
01260 int ast_internal_timing_enabled(struct ast_channel *chan);
01261 
01262 /* Misc. functions below */
01263 
01264 /*! \brief if fd is a valid descriptor, set *pfd with the descriptor
01265  * \return Return 1 (not -1!) if added, 0 otherwise (so we can add the
01266  * return value to the index into the array)
01267  */
01268 static inline int ast_add_fd(struct pollfd *pfd, int fd)
01269 {
01270    pfd->fd = fd;
01271    pfd->events = POLLIN | POLLPRI;
01272    return fd >= 0;
01273 }
01274 
01275 /*! \brief Helper function for migrating select to poll */
01276 static inline int ast_fdisset(struct pollfd *pfds, int fd, int max, int *start)
01277 {
01278    int x;
01279    int dummy=0;
01280 
01281    if (fd < 0)
01282       return 0;
01283    if (!start)
01284       start = &dummy;
01285    for (x = *start; x<max; x++)
01286       if (pfds[x].fd == fd) {
01287          if (x == *start)
01288             (*start)++;
01289          return pfds[x].revents;
01290       }
01291    return 0;
01292 }
01293 
01294 #ifdef SOLARIS
01295 static inline void timersub(struct timeval *tvend, struct timeval *tvstart, struct timeval *tvdiff)
01296 {
01297    tvdiff->tv_sec = tvend->tv_sec - tvstart->tv_sec;
01298    tvdiff->tv_usec = tvend->tv_usec - tvstart->tv_usec;
01299    if (tvdiff->tv_usec < 0) {
01300       tvdiff->tv_sec --;
01301       tvdiff->tv_usec += 1000000;
01302    }
01303 
01304 }
01305 #endif
01306 
01307 /*! \brief Waits for activity on a group of channels 
01308  * \param nfds the maximum number of file descriptors in the sets
01309  * \param rfds file descriptors to check for read availability
01310  * \param wfds file descriptors to check for write availability
01311  * \param efds file descriptors to check for exceptions (OOB data)
01312  * \param tvp timeout while waiting for events
01313  * This is the same as a standard select(), except it guarantees the
01314  * behaviour where the passed struct timeval is updated with how much
01315  * time was not slept while waiting for the specified events
01316  */
01317 static inline int ast_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *tvp)
01318 {
01319 #ifdef __linux__
01320    return select(nfds, rfds, wfds, efds, tvp);
01321 #else
01322    if (tvp) {
01323       struct timeval tv, tvstart, tvend, tvlen;
01324       int res;
01325 
01326       tv = *tvp;
01327       gettimeofday(&tvstart, NULL);
01328       res = select(nfds, rfds, wfds, efds, tvp);
01329       gettimeofday(&tvend, NULL);
01330       timersub(&tvend, &tvstart, &tvlen);
01331       timersub(&tv, &tvlen, tvp);
01332       if (tvp->tv_sec < 0 || (tvp->tv_sec == 0 && tvp->tv_usec < 0)) {
01333          tvp->tv_sec = 0;
01334          tvp->tv_usec = 0;
01335       }
01336       return res;
01337    }
01338    else
01339       return select(nfds, rfds, wfds, efds, NULL);
01340 #endif
01341 }
01342 
01343 #define CHECK_BLOCKING(c) do {    \
01344    if (ast_test_flag(c, AST_FLAG_BLOCKING)) {\
01345       if (option_debug) \
01346          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); \
01347    } else { \
01348       (c)->blocker = pthread_self(); \
01349       (c)->blockproc = __PRETTY_FUNCTION__; \
01350       ast_set_flag(c, AST_FLAG_BLOCKING); \
01351    } } while (0)
01352 
01353 ast_group_t ast_get_group(const char *s);
01354 
01355 /*! \brief print call- and pickup groups into buffer */
01356 char *ast_print_group(char *buf, int buflen, ast_group_t group);
01357 
01358 /*! \brief Convert enum channelreloadreason to text string for manager event
01359    \param reason  Enum channelreloadreason - reason for reload (manager, cli, start etc)
01360 */
01361 const char *channelreloadreason2txt(enum channelreloadreason reason);
01362 
01363 /*! \brief return an ast_variable list of channeltypes */
01364 struct ast_variable *ast_channeltype_list(void);
01365 
01366 /*!
01367   \brief Begin 'whispering' onto a channel
01368   \param chan The channel to whisper onto
01369   \return 0 for success, non-zero for failure
01370 
01371   This function will add a whisper buffer onto a channel and set a flag
01372   causing writes to the channel to reduce the volume level of the written
01373   audio samples, and then to mix in audio from the whisper buffer if it
01374   is available.
01375 
01376   Note: This function performs no locking; you must hold the channel's lock before
01377   calling this function.
01378  */
01379 int ast_channel_whisper_start(struct ast_channel *chan);
01380 
01381 /*!
01382   \brief Feed an audio frame into the whisper buffer on a channel
01383   \param chan The channel to whisper onto
01384   \param f The frame to to whisper onto chan
01385   \return 0 for success, non-zero for failure
01386  */
01387 int ast_channel_whisper_feed(struct ast_channel *chan, struct ast_frame *f);
01388 
01389 /*!
01390   \brief Stop 'whispering' onto a channel
01391   \param chan The channel to whisper onto
01392   \return 0 for success, non-zero for failure
01393 
01394   Note: This function performs no locking; you must hold the channel's lock before
01395   calling this function.
01396  */
01397 void ast_channel_whisper_stop(struct ast_channel *chan);
01398 
01399 
01400 
01401 /*!
01402   \brief return an english explanation of the code returned thru __ast_request_and_dial's 'outstate' argument
01403   \param reason  The integer argument, usually taken from AST_CONTROL_ macros
01404   \return char pointer explaining the code
01405  */
01406 char *ast_channel_reason2str(int reason);
01407 
01408 
01409 #if defined(__cplusplus) || defined(c_plusplus)
01410 }
01411 #endif
01412 
01413 #endif /* _ASTERISK_CHANNEL_H */

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