Thu Oct 11 06:42:06 2012

Asterisk developer's documentation


channel.h

Go to the documentation of this file.
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 
00094 #include "asterisk/poll-compat.h"
00095 
00096 #if defined(__cplusplus) || defined(c_plusplus)
00097 extern "C" {
00098 #endif
00099 
00100 #define AST_MAX_EXTENSION  80 /*!< Max length of an extension */
00101 #define AST_MAX_CONTEXT    80 /*!< Max length of a context */
00102 #define AST_CHANNEL_NAME   80 /*!< Max length of an ast_channel name */
00103 #define MAX_LANGUAGE    20 /*!< Max length of the language setting */
00104 #define MAX_MUSICCLASS     80 /*!< Max length of the music class setting */
00105 
00106 #include "asterisk/compat.h"
00107 #include "asterisk/frame.h"
00108 #include "asterisk/sched.h"
00109 #include "asterisk/chanvars.h"
00110 #include "asterisk/config.h"
00111 #include "asterisk/lock.h"
00112 #include "asterisk/cdr.h"
00113 #include "asterisk/utils.h"
00114 #include "asterisk/linkedlists.h"
00115 #include "asterisk/stringfields.h"
00116 #include "asterisk/compiler.h"
00117 
00118 #define DATASTORE_INHERIT_FOREVER   INT_MAX
00119 
00120 #define AST_MAX_FDS     8
00121 /*
00122  * We have AST_MAX_FDS file descriptors in a channel.
00123  * Some of them have a fixed use:
00124  */
00125 #define AST_ALERT_FD (AST_MAX_FDS-1)      /*!< used for alertpipe */
00126 #define AST_TIMING_FD   (AST_MAX_FDS-2)      /*!< used for timingfd */
00127 #define AST_AGENT_FD (AST_MAX_FDS-3)      /*!< used by agents for pass through */
00128 #define AST_GENERATOR_FD   (AST_MAX_FDS-4)   /*!< used by generator */
00129 
00130 enum ast_bridge_result {
00131    AST_BRIDGE_COMPLETE = 0,
00132    AST_BRIDGE_FAILED = -1,
00133    AST_BRIDGE_FAILED_NOWARN = -2,
00134    AST_BRIDGE_RETRY = -3,
00135 };
00136 
00137 typedef unsigned long long ast_group_t;
00138 
00139 struct ast_generator {
00140    void *(*alloc)(struct ast_channel *chan, void *params);
00141    void (*release)(struct ast_channel *chan, void *data);
00142    /*! This function gets called with the channel unlocked, but is called in
00143     *  the context of the channel thread so we know the channel is not going
00144     *  to disappear.  This callback is responsible for locking the channel as
00145     *  necessary. */
00146    int (*generate)(struct ast_channel *chan, void *data, int len, int samples);
00147 };
00148 
00149 /*! \brief Structure for a data store type */
00150 struct ast_datastore_info {
00151    const char *type;    /*!< Type of data store */
00152    void *(*duplicate)(void *data); /*!< Duplicate item data (used for inheritance) */
00153    void (*destroy)(void *data);  /*!< Destroy function */
00154    /*!
00155     * \brief Fix up channel references
00156     *
00157     * \arg data The datastore data
00158     * \arg old_chan The old channel owning the datastore
00159     * \arg new_chan The new channel owning the datastore
00160     *
00161     * This is exactly like the fixup callback of the channel technology interface.
00162     * It allows a datastore to fix any pointers it saved to the owning channel
00163     * in case that the owning channel has changed.  Generally, this would happen
00164     * when the datastore is set to be inherited, and a masquerade occurs.
00165     *
00166     * \return nothing.
00167     */
00168    void (*chan_fixup)(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan);
00169 };
00170 
00171 /*! \brief Structure for a channel data store */
00172 struct ast_datastore {
00173    char *uid;     /*!< Unique data store identifier */
00174    void *data;    /*!< Contained data */
00175    const struct ast_datastore_info *info; /*!< Data store type information */
00176    unsigned int inheritance;  /*!Number of levels this item will continue to be inherited */
00177    AST_LIST_ENTRY(ast_datastore) entry; /*!< Used for easy linking */
00178 };
00179 
00180 /*! \brief Structure for all kinds of caller ID identifications.
00181  * \note All string fields here are malloc'ed, so they need to be
00182  * freed when the structure is deleted.
00183  * Also, NULL and "" must be considered equivalent.
00184  */
00185 struct ast_callerid {
00186    char *cid_dnid;      /*!< Malloc'd Dialed Number Identifier */
00187    char *cid_num;    /*!< Malloc'd Caller Number */
00188    char *cid_name;      /*!< Malloc'd Caller Name */
00189    char *cid_ani;    /*!< Malloc'd ANI */
00190    char *cid_rdnis;  /*!< Malloc'd RDNIS */
00191    int cid_pres;     /*!< Callerid presentation/screening */
00192    int cid_ani2;     /*!< Callerid ANI 2 (Info digits) */
00193    int cid_ton;      /*!< Callerid Type of Number */
00194    int cid_tns;      /*!< Callerid Transit Network Select */
00195 };
00196 
00197 /*! \brief Typedef for a custom read function */
00198 typedef int (*ast_acf_read_fn_t)(struct ast_channel *, char *, char *, char *, size_t);
00199 
00200 /*! \brief Typedef for a custom write function */
00201 typedef int (*ast_acf_write_fn_t)(struct ast_channel *, char *, char *, const char *);
00202 
00203 /*! \brief Structure to handle passing func_channel_write info to channels via setoption */
00204 typedef struct {
00205    /*! \brief ast_chan_write_info_t version. Must be incremented if structure is changed */
00206    #define AST_CHAN_WRITE_INFO_T_VERSION 1
00207    uint32_t version;
00208    ast_acf_write_fn_t write_fn;
00209    struct ast_channel *chan;
00210    char *function;
00211    char *data;
00212    const char *value;
00213 } ast_chan_write_info_t;
00214 
00215 /*! \brief 
00216    Structure to describe a channel "technology", ie a channel driver 
00217    See for examples:
00218    \arg chan_iax2.c - The Inter-Asterisk exchange protocol
00219    \arg chan_sip.c - The SIP channel driver
00220    \arg chan_zap.c - PSTN connectivity (TDM, PRI, T1/E1, FXO, FXS)
00221 
00222    If you develop your own channel driver, this is where you
00223    tell the PBX at registration of your driver what properties
00224    this driver supports and where different callbacks are 
00225    implemented.
00226 */
00227 struct ast_channel_tech {
00228    const char * const type;
00229    const char * const description;
00230 
00231    int capabilities;    /*!< Bitmap of formats this channel can handle */
00232 
00233    int properties;         /*!< Technology Properties */
00234 
00235    /*! \brief Requester - to set up call data structures (pvt's) */
00236    struct ast_channel *(* const requester)(const char *type, int format, void *data, int *cause);
00237 
00238    int (* const devicestate)(void *data); /*!< Devicestate call back */
00239 
00240    /*! \brief Start sending a literal DTMF digit */
00241    int (* const send_digit_begin)(struct ast_channel *chan, char digit);
00242 
00243    /*! \brief Stop sending a literal DTMF digit */
00244    int (* const send_digit_end)(struct ast_channel *chan, char digit, unsigned int duration);
00245 
00246    /*! \brief Call a given phone number (address, etc), but don't
00247       take longer than timeout seconds to do so.  */
00248    int (* const call)(struct ast_channel *chan, char *addr, int timeout);
00249 
00250    /*! \brief Hangup (and possibly destroy) the channel */
00251    int (* const hangup)(struct ast_channel *chan);
00252 
00253    /*! \brief Answer the channel */
00254    int (* const answer)(struct ast_channel *chan);
00255 
00256    /*! \brief Read a frame, in standard format (see frame.h) */
00257    struct ast_frame * (* const read)(struct ast_channel *chan);
00258 
00259    /*! \brief Write a frame, in standard format (see frame.h) */
00260    int (* const write)(struct ast_channel *chan, struct ast_frame *frame);
00261 
00262    /*! \brief Display or transmit text */
00263    int (* const send_text)(struct ast_channel *chan, const char *text);
00264 
00265    /*! \brief Display or send an image */
00266    int (* const send_image)(struct ast_channel *chan, struct ast_frame *frame);
00267 
00268    /*! \brief Send HTML data */
00269    int (* const send_html)(struct ast_channel *chan, int subclass, const char *data, int len);
00270 
00271    /*! \brief Handle an exception, reading a frame */
00272    struct ast_frame * (* const exception)(struct ast_channel *chan);
00273 
00274    /*! \brief Bridge two channels of the same type together */
00275    enum ast_bridge_result (* const bridge)(struct ast_channel *c0, struct ast_channel *c1, int flags,
00276                   struct ast_frame **fo, struct ast_channel **rc, int timeoutms);
00277 
00278    /*! \brief Indicate a particular condition (e.g. AST_CONTROL_BUSY or AST_CONTROL_RINGING or AST_CONTROL_CONGESTION */
00279    int (* const indicate)(struct ast_channel *c, int condition, const void *data, size_t datalen);
00280 
00281    /*! \brief Fix up a channel:  If a channel is consumed, this is called.  Basically update any ->owner links */
00282    int (* const fixup)(struct ast_channel *oldchan, struct ast_channel *newchan);
00283 
00284    /*! \brief Set a given option */
00285    int (* const setoption)(struct ast_channel *chan, int option, void *data, int datalen);
00286 
00287    /*! \brief Query a given option */
00288    int (* const queryoption)(struct ast_channel *chan, int option, void *data, int *datalen);
00289 
00290    /*! \brief Blind transfer other side (see app_transfer.c and ast_transfer() */
00291    int (* const transfer)(struct ast_channel *chan, const char *newdest);
00292 
00293    /*! \brief Write a frame, in standard format */
00294    int (* const write_video)(struct ast_channel *chan, struct ast_frame *frame);
00295 
00296    /*! \brief Find bridged channel */
00297    struct ast_channel *(* const bridged_channel)(struct ast_channel *chan, struct ast_channel *bridge);
00298 
00299    /*! \brief Provide additional read items for CHANNEL() dialplan function */
00300    int (* func_channel_read)(struct ast_channel *chan, char *function, char *data, char *buf, size_t len);
00301 
00302    /*! \brief Provide additional write items for CHANNEL() dialplan function */
00303    int (* func_channel_write)(struct ast_channel *chan, char *function, char *data, const char *value);
00304 
00305    /*! \brief Retrieve base channel (agent and local) */
00306    struct ast_channel* (* get_base_channel)(struct ast_channel *chan);
00307    
00308    /*! \brief Set base channel (agent and local) */
00309    int (* set_base_channel)(struct ast_channel *chan, struct ast_channel *base);
00310 };
00311 
00312 #define  DEBUGCHAN_FLAG  0x80000000
00313 #define  FRAMECOUNT_INC(x) ( ((x) & DEBUGCHAN_FLAG) | (((x)+1) & ~DEBUGCHAN_FLAG) )
00314 
00315 enum ast_channel_adsicpe {
00316    AST_ADSI_UNKNOWN,
00317    AST_ADSI_AVAILABLE,
00318    AST_ADSI_UNAVAILABLE,
00319    AST_ADSI_OFFHOOKONLY,
00320 };
00321 
00322 /*! 
00323  * \brief ast_channel states
00324  *
00325  * \note Bits 0-15 of state are reserved for the state (up/down) of the line
00326  *       Bits 16-32 of state are reserved for flags
00327  */
00328 enum ast_channel_state {
00329    /*! Channel is down and available */
00330    AST_STATE_DOWN,
00331    /*! Channel is down, but reserved */
00332    AST_STATE_RESERVED,
00333    /*! Channel is off hook */
00334    AST_STATE_OFFHOOK,
00335    /*! Digits (or equivalent) have been dialed */
00336    AST_STATE_DIALING,
00337    /*! Line is ringing */
00338    AST_STATE_RING,
00339    /*! Remote end is ringing */
00340    AST_STATE_RINGING,
00341    /*! Line is up */
00342    AST_STATE_UP,
00343    /*! Line is busy */
00344    AST_STATE_BUSY,
00345    /*! Digits (or equivalent) have been dialed while offhook */
00346    AST_STATE_DIALING_OFFHOOK,
00347    /*! Channel has detected an incoming call and is waiting for ring */
00348    AST_STATE_PRERING,
00349 
00350    /*! Do not transmit voice data */
00351    AST_STATE_MUTE = (1 << 16),
00352 };
00353 
00354 /*! \brief Main Channel structure associated with a channel. 
00355  * This is the side of it mostly used by the pbx and call management.
00356  *
00357  * \note XXX It is important to remember to increment .cleancount each time
00358  *       this structure is changed. XXX
00359  */
00360 struct ast_channel {
00361    /*! \brief Technology (point to channel driver) */
00362    const struct ast_channel_tech *tech;
00363 
00364    /*! \brief Private data used by the technology driver */
00365    void *tech_pvt;
00366 
00367    AST_DECLARE_STRING_FIELDS(
00368       AST_STRING_FIELD(name);       /*!< ASCII unique channel name */
00369       AST_STRING_FIELD(language);      /*!< Language requested for voice prompts */
00370       AST_STRING_FIELD(musicclass);    /*!< Default music class */
00371       AST_STRING_FIELD(accountcode);      /*!< Account code for billing */
00372       AST_STRING_FIELD(call_forward);     /*!< Where to forward to if asked to dial on this interface */
00373       AST_STRING_FIELD(uniqueid);      /*!< Unique Channel Identifier */
00374    );
00375    
00376    /*! \brief File descriptor for channel -- Drivers will poll on these file descriptors, so at least one must be non -1.  */
00377    int fds[AST_MAX_FDS];         
00378 
00379    void *music_state;            /*!< Music State*/
00380    void *generatordata;          /*!< Current generator data if there is any */
00381    struct ast_generator *generator;    /*!< Current active data generator */
00382 
00383    /*! \brief Who are we bridged to, if we're bridged. Who is proxying for us,
00384      if we are proxied (i.e. chan_agent).
00385      Do not access directly, use ast_bridged_channel(chan) */
00386    struct ast_channel *_bridge;
00387    struct ast_channel *masq;        /*!< Channel that will masquerade as us */
00388    struct ast_channel *masqr;       /*!< Who we are masquerading as */
00389    int cdrflags;              /*!< Call Detail Record Flags */
00390 
00391    /*! \brief Whether or not we have been hung up...  Do not set this value
00392        directly, use ast_softhangup */
00393    int _softhangup;
00394    time_t   whentohangup;           /*!< Non-zero, set to actual time when channel is to be hung up */
00395    pthread_t blocker;            /*!< If anyone is blocking, this is them */
00396    ast_mutex_t lock;          /*!< Lock, can be used to lock a channel for some operations */
00397    const char *blockproc;           /*!< Procedure causing blocking */
00398 
00399    const char *appl;          /*!< Current application */
00400    const char *data;          /*!< Data passed to current application */
00401    int fdno;               /*!< Which fd had an event detected on */
00402    struct sched_context *sched;        /*!< Schedule context */
00403    int streamid;              /*!< For streaming playback, the schedule ID */
00404    struct ast_filestream *stream;         /*!< Stream itself. */
00405    int vstreamid;             /*!< For streaming video playback, the schedule ID */
00406    struct ast_filestream *vstream;        /*!< Video Stream itself. */
00407    int oldwriteformat;           /*!< Original writer format */
00408    
00409    int timingfd;              /*!< Timing fd */
00410    int (*timingfunc)(const void *data);
00411    void *timingdata;
00412 
00413    enum ast_channel_state _state;         /*!< State of line -- Don't write directly, use ast_setstate */
00414    int rings;              /*!< Number of rings so far */
00415    struct ast_callerid cid;         /*!< Caller ID, name, presentation etc */
00416    char unused_old_dtmfq[AST_MAX_EXTENSION]; /*!< The DTMFQ is deprecated.  All frames should go to the readq. */
00417    struct ast_frame dtmff;          /*!< DTMF frame */
00418 
00419    char context[AST_MAX_CONTEXT];         /*!< Dialplan: Current extension context */
00420    char exten[AST_MAX_EXTENSION];         /*!< Dialplan: Current extension number */
00421    int priority;              /*!< Dialplan: Current extension priority */
00422    char macrocontext[AST_MAX_CONTEXT];    /*!< Macro: Current non-macro context. See app_macro.c */
00423    char macroexten[AST_MAX_EXTENSION];    /*!< Macro: Current non-macro extension. See app_macro.c */
00424    int macropriority;            /*!< Macro: Current non-macro priority. See app_macro.c */
00425    char dialcontext[AST_MAX_CONTEXT];              /*!< Dial: Extension context that we were called from */
00426 
00427    struct ast_pbx *pbx;          /*!< PBX private structure for this channel */
00428    int amaflags;              /*!< Set BEFORE PBX is started to determine AMA flags */
00429    struct ast_cdr *cdr;          /*!< Call Detail Record */
00430    enum ast_channel_adsicpe adsicpe;      /*!< Whether or not ADSI is detected on CPE */
00431 
00432    struct tone_zone *zone;          /*!< Tone zone as set in indications.conf or
00433                         in the CHANNEL dialplan function */
00434 
00435    struct ast_channel_monitor *monitor;      /*!< Channel monitoring */
00436 
00437    /*! Track the read/written samples for monitor use */
00438    unsigned long insmpl;
00439    unsigned long outsmpl;
00440 
00441    /* Frames in/out counters. The high bit is a debug mask, so
00442     * the counter is only in the remaining bits
00443     */
00444    unsigned int fin;
00445    unsigned int fout;
00446    int hangupcause;           /*!< Why is the channel hanged up. See causes.h */
00447    struct varshead varshead;        /*!< A linked list for channel variables */
00448    ast_group_t callgroup;           /*!< Call group for call pickups */
00449    ast_group_t pickupgroup;         /*!< Pickup group - which calls groups can be picked up? */
00450    unsigned int flags;           /*!< channel flags of AST_FLAG_ type */
00451    unsigned short transfercapability;     /*!< ISDN Transfer Capbility - AST_FLAG_DIGITAL is not enough */
00452    AST_LIST_HEAD_NOLOCK(, ast_frame) readq;
00453    int alertpipe[2];
00454 
00455    int nativeformats;            /*!< Kinds of data this channel can natively handle */
00456    int readformat;               /*!< Requested read format */
00457    int writeformat;           /*!< Requested write format */
00458    struct ast_trans_pvt *writetrans;      /*!< Write translation path */
00459    struct ast_trans_pvt *readtrans;    /*!< Read translation path */
00460    int rawreadformat;            /*!< Raw read format */
00461    int rawwriteformat;           /*!< Raw write format */
00462 
00463    struct ast_audiohook_list *audiohooks;
00464    void *unused; /*! This pointer should stay for Asterisk 1.4.  It just keeps the struct size the same
00465           *  for the sake of ABI compatability. */
00466 
00467    AST_LIST_ENTRY(ast_channel) chan_list;    /*!< For easy linking */
00468    
00469    struct ast_jb jb;          /*!< The jitterbuffer state  */
00470 
00471    char emulate_dtmf_digit;         /*!< Digit being emulated */
00472    unsigned int emulate_dtmf_duration; /*!< Number of ms left to emulate DTMF for */
00473    struct timeval dtmf_tv;       /*!< The time that an in process digit began, or the last digit ended */
00474 
00475    int visible_indication;                         /*!< Indication currently playing on the channel */
00476 
00477    /*! \brief Data stores on the channel */
00478    AST_LIST_HEAD_NOLOCK(datastores, ast_datastore) datastores;
00479 };
00480 
00481 /*! \brief ast_channel_tech Properties */
00482 enum {
00483    /*! \brief Channels have this property if they can accept input with jitter; 
00484     *         i.e. most VoIP channels */
00485    AST_CHAN_TP_WANTSJITTER = (1 << 0),
00486    /*! \brief Channels have this property if they can create jitter; 
00487     *         i.e. most VoIP channels */
00488    AST_CHAN_TP_CREATESJITTER = (1 << 1),
00489 };
00490 
00491 /*! \brief ast_channel flags */
00492 enum {
00493    /*! Queue incoming dtmf, to be released when this flag is turned off */
00494    AST_FLAG_DEFER_DTMF =    (1 << 1),
00495    /*! write should be interrupt generator */
00496    AST_FLAG_WRITE_INT =     (1 << 2),
00497    /*! a thread is blocking on this channel */
00498    AST_FLAG_BLOCKING =      (1 << 3),
00499    /*! This is a zombie channel */
00500    AST_FLAG_ZOMBIE =        (1 << 4),
00501    /*! There is an exception pending */
00502    AST_FLAG_EXCEPTION =     (1 << 5),
00503    /*! Listening to moh XXX anthm promises me this will disappear XXX */
00504    AST_FLAG_MOH =           (1 << 6),
00505    /*! This channel is spying on another channel */
00506    AST_FLAG_SPYING =        (1 << 7),
00507    /*! This channel is in a native bridge */
00508    AST_FLAG_NBRIDGE =       (1 << 8),
00509    /*! the channel is in an auto-incrementing dialplan processor,
00510     *  so when ->priority is set, it will get incremented before
00511     *  finding the next priority to run */
00512    AST_FLAG_IN_AUTOLOOP =   (1 << 9),
00513    /*! This is an outgoing call */
00514    AST_FLAG_OUTGOING =      (1 << 10),
00515    /*! This channel is being whispered on */
00516    AST_FLAG_WHISPER =       (1 << 11),
00517    /*! A DTMF_BEGIN frame has been read from this channel, but not yet an END */
00518    AST_FLAG_IN_DTMF =       (1 << 12),
00519    /*! A DTMF_END was received when not IN_DTMF, so the length of the digit is 
00520     *  currently being emulated */
00521    AST_FLAG_EMULATE_DTMF =  (1 << 13),
00522    /*! This is set to tell the channel not to generate DTMF begin frames, and
00523     *  to instead only generate END frames. */
00524    AST_FLAG_END_DTMF_ONLY = (1 << 14),
00525    /*! This flag indicates that on a masquerade, an active stream should not
00526     *  be carried over */
00527    AST_FLAG_MASQ_NOSTREAM = (1 << 15),
00528    /*! This flag indicates that the hangup exten was run when the bridge terminated,
00529     *  a message aimed at preventing a subsequent hangup exten being run at the pbx_run
00530     *  level */
00531    AST_FLAG_BRIDGE_HANGUP_RUN = (1 << 16),
00532    /*! This flag indicates that the hangup exten should NOT be run when the 
00533     *  bridge terminates, this will allow the hangup in the pbx loop to be run instead.
00534     *  */
00535    AST_FLAG_BRIDGE_HANGUP_DONT = (1 << 17),
00536    /*! This flag indicates whether the channel is in the channel list or not. */
00537    AST_FLAG_IN_CHANNEL_LIST = (1 << 19),
00538    /*! Disable certain workarounds.  This reintroduces certain bugs, but allows
00539     *  some non-traditional dialplans (like AGI) to continue to function.
00540     */
00541    AST_FLAG_DISABLE_WORKAROUNDS = (1 << 20),
00542 };
00543 
00544 /*! \brief ast_bridge_config flags */
00545 enum {
00546    AST_FEATURE_PLAY_WARNING = (1 << 0),
00547    AST_FEATURE_REDIRECT =     (1 << 1),
00548    AST_FEATURE_DISCONNECT =   (1 << 2),
00549    AST_FEATURE_ATXFER =       (1 << 3),
00550    AST_FEATURE_AUTOMON =      (1 << 4),
00551    AST_FEATURE_PARKCALL =     (1 << 5),
00552    AST_FEATURE_NO_H_EXTEN =   (1 << 6),
00553    AST_FEATURE_WARNING_ACTIVE = (1 << 7),
00554 };
00555 
00556 struct ast_bridge_config {
00557    struct ast_flags features_caller;
00558    struct ast_flags features_callee;
00559    struct timeval start_time;
00560    struct timeval nexteventts;
00561    struct timeval partialfeature_timer;
00562    long feature_timer;
00563    long timelimit;
00564    long play_warning;
00565    long warning_freq;
00566    const char *warning_sound;
00567    const char *end_sound;
00568    const char *start_sound;
00569    int firstpass;
00570    unsigned int flags;
00571    void (* end_bridge_callback)(void *);   /*!< A callback that is called after a bridge attempt */
00572    void *end_bridge_callback_data;         /*!< Data passed to the callback */
00573    /*! If the end_bridge_callback_data refers to a channel which no longer is going to
00574     * exist when the end_bridge_callback is called, then it needs to be fixed up properly
00575     */
00576    void (*end_bridge_callback_data_fixup)(struct ast_bridge_config *bconfig, struct ast_channel *originator, struct ast_channel *terminator);
00577 };
00578 
00579 struct chanmon;
00580 
00581 #define LOAD_OH(oh) {   \
00582    oh.context = context; \
00583    oh.exten = exten; \
00584    oh.priority = priority; \
00585    oh.cid_num = cid_num; \
00586    oh.cid_name = cid_name; \
00587    oh.account = account; \
00588    oh.vars = vars; \
00589    oh.parent_channel = NULL; \
00590 } 
00591 
00592 struct outgoing_helper {
00593    const char *context;
00594    const char *exten;
00595    int priority;
00596    const char *cid_num;
00597    const char *cid_name;
00598    const char *account;
00599    struct ast_variable *vars;
00600    struct ast_channel *parent_channel;
00601 };
00602 
00603 enum {
00604    AST_CDR_TRANSFER =   (1 << 0),
00605    AST_CDR_FORWARD =    (1 << 1),
00606    AST_CDR_CALLWAIT =   (1 << 2),
00607    AST_CDR_CONFERENCE = (1 << 3),
00608 };
00609 
00610 enum {
00611    /*!
00612     * Soft hangup requested by device or other internal reason.
00613     * Actual hangup needed.
00614     */
00615    AST_SOFTHANGUP_DEV =       (1 << 0),
00616    /*!
00617     * Used to break the normal frame flow so an async goto can be
00618     * done instead of actually hanging up.
00619     */
00620    AST_SOFTHANGUP_ASYNCGOTO = (1 << 1),
00621    /*!
00622     * Soft hangup requested by system shutdown.  Actual hangup
00623     * needed.
00624     */
00625    AST_SOFTHANGUP_SHUTDOWN =  (1 << 2),
00626    /*!
00627     * Used to break the normal frame flow after a timeout so an
00628     * implicit async goto can be done to the 'T' exten if it exists
00629     * instead of actually hanging up.  If the exten does not exist
00630     * then actually hangup.
00631     */
00632    AST_SOFTHANGUP_TIMEOUT =   (1 << 3),
00633    /*!
00634     * Soft hangup requested by application/channel-driver being
00635     * unloaded.  Actual hangup needed.
00636     */
00637    AST_SOFTHANGUP_APPUNLOAD = (1 << 4),
00638    /*!
00639     * Soft hangup requested by non-associated party.  Actual hangup
00640     * needed.
00641     */
00642    AST_SOFTHANGUP_EXPLICIT =  (1 << 5),
00643    /*!
00644     * Used to break a bridge so the channel can be spied upon
00645     * instead of actually hanging up.
00646     */
00647    AST_SOFTHANGUP_UNBRIDGE =  (1 << 6),
00648 
00649 
00650    /*!
00651     * \brief All softhangup flags.
00652     *
00653     * This can be used as an argument to ast_channel_softhangup_clear
00654     * to clear all softhangup flags from a channel.
00655     */
00656    AST_SOFTHANGUP_ALL =       (0xFFFFFFFF)
00657 };
00658 
00659 
00660 /*! \brief Channel reload reasons for manager events at load or reload of configuration */
00661 enum channelreloadreason {
00662    CHANNEL_MODULE_LOAD,
00663    CHANNEL_MODULE_RELOAD,
00664    CHANNEL_CLI_RELOAD,
00665    CHANNEL_MANAGER_RELOAD,
00666 };
00667 
00668 /*! \brief Create a channel datastore structure */
00669 struct ast_datastore *ast_channel_datastore_alloc(const struct ast_datastore_info *info, char *uid);
00670 
00671 /*! \brief Free a channel datastore structure */
00672 int ast_channel_datastore_free(struct ast_datastore *datastore);
00673 
00674 /*! \brief Inherit datastores from a parent to a child. */
00675 int ast_channel_datastore_inherit(struct ast_channel *from, struct ast_channel *to);
00676 
00677 /*! \brief Add a datastore to a channel */
00678 int ast_channel_datastore_add(struct ast_channel *chan, struct ast_datastore *datastore);
00679 
00680 /*! \brief Remove a datastore from a channel */
00681 int ast_channel_datastore_remove(struct ast_channel *chan, struct ast_datastore *datastore);
00682 
00683 /*! \brief Find a datastore on a channel */
00684 struct ast_datastore *ast_channel_datastore_find(struct ast_channel *chan, const struct ast_datastore_info *info, char *uid);
00685 
00686 /*! \brief Change the state of a channel */
00687 int ast_setstate(struct ast_channel *chan, enum ast_channel_state);
00688 
00689 /*! \brief Create a channel structure 
00690     \return Returns NULL on failure to allocate.
00691    \note New channels are 
00692    by default set to the "default" context and
00693    extension "s"
00694  */
00695 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)));
00696 
00697 /*!
00698  * \brief Queue one or more frames to a channel's frame queue
00699  *
00700  * \param chan the channel to queue the frame(s) on
00701  * \param f the frame(s) to queue.  Note that the frame(s) will be duplicated
00702  *        by this function.  It is the responsibility of the caller to handle
00703  *        freeing the memory associated with the frame(s) being passed if
00704  *        necessary.
00705  *
00706  * \retval 0 success
00707  * \retval non-zero failure
00708  */
00709 int ast_queue_frame(struct ast_channel *chan, struct ast_frame *f);
00710 
00711 /*!
00712  * \brief Queue one or more frames to the head of a channel's frame queue
00713  *
00714  * \param chan the channel to queue the frame(s) on
00715  * \param f the frame(s) to queue.  Note that the frame(s) will be duplicated
00716  *        by this function.  It is the responsibility of the caller to handle
00717  *        freeing the memory associated with the frame(s) being passed if
00718  *        necessary.
00719  *
00720  * \retval 0 success
00721  * \retval non-zero failure
00722  */
00723 int ast_queue_frame_head(struct ast_channel *chan, struct ast_frame *f);
00724 
00725 /*! \brief Queue a hangup frame */
00726 int ast_queue_hangup(struct ast_channel *chan);
00727 
00728 /*!
00729   \brief Queue a control frame with payload
00730   \param chan channel to queue frame onto
00731   \param control type of control frame
00732   \return zero on success, non-zero on failure
00733 */
00734 int ast_queue_control(struct ast_channel *chan, enum ast_control_frame_type control);
00735 
00736 /*!
00737   \brief Queue a control frame with payload
00738   \param chan channel to queue frame onto
00739   \param control type of control frame
00740   \param data pointer to payload data to be included in frame
00741   \param datalen number of bytes of payload data
00742   \return zero on success, non-zero on failure
00743 
00744   The supplied payload data is copied into the frame, so the caller's copy
00745   is not modified nor freed, and the resulting frame will retain a copy of
00746   the data even if the caller frees their local copy.
00747 
00748   \note This method should be treated as a 'network transport'; in other
00749   words, your frames may be transferred across an IAX2 channel to another
00750   system, which may be a different endianness than yours. Because of this,
00751   you should ensure that either your frames will never be expected to work
00752   across systems, or that you always put your payload data into 'network byte
00753   order' before calling this function.
00754 */
00755 int ast_queue_control_data(struct ast_channel *chan, enum ast_control_frame_type control,
00756             const void *data, size_t datalen);
00757 
00758 /*! \brief Change channel name */
00759 void ast_change_name(struct ast_channel *chan, char *newname);
00760 
00761 /*! \brief Free a channel structure */
00762 void  ast_channel_free(struct ast_channel *);
00763 
00764 /*! \brief Requests a channel 
00765  * \param type type of channel to request
00766  * \param format requested channel format (codec)
00767  * \param data data to pass to the channel requester
00768  * \param status status
00769  * Request a channel of a given type, with data as optional information used 
00770  * by the low level module
00771  * \return Returns an ast_channel on success, NULL on failure.
00772  */
00773 struct ast_channel *ast_request(const char *type, int format, void *data, int *status);
00774 
00775 /*!
00776  * \brief Request a channel of a given type, with data as optional information used 
00777  * by the low level module and attempt to place a call on it
00778  * \param type type of channel to request
00779  * \param format requested channel format
00780  * \param data data to pass to the channel requester
00781  * \param timeout maximum amount of time to wait for an answer
00782  * \param reason why unsuccessful (if unsuceessful)
00783  * \param cidnum Caller-ID Number
00784  * \param cidname Caller-ID Name
00785  * \return Returns an ast_channel on success or no answer, NULL on failure.  Check the value of chan->_state
00786  * to know if the call was answered or not.
00787  */
00788 struct ast_channel *ast_request_and_dial(const char *type, int format, void *data, int timeout, int *reason, const char *cidnum, const char *cidname);
00789 
00790 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);
00791 
00792 /*!
00793 * \brief Forwards a call to a new channel specified by the original channel's call_forward str.  If possible, the new forwarded channel is created and returned while the original one is terminated.
00794 * \param caller in channel that requested orig
00795 * \param orig channel being replaced by the call forward channel
00796 * \param timeout maximum amount of time to wait for setup of new forward channel
00797 * \param format requested channel format
00798 * \param oh outgoing helper used with original channel
00799 * \param outstate reason why unsuccessful (if uncuccessful)
00800 * \return Returns the forwarded call's ast_channel on success or NULL on failure
00801 */
00802 struct ast_channel *ast_call_forward(struct ast_channel *caller, struct ast_channel *orig, int *timeout, int format, struct outgoing_helper *oh, int *outstate);
00803 
00804 /*!\brief Register a channel technology (a new channel driver)
00805  * Called by a channel module to register the kind of channels it supports.
00806  * \param tech Structure defining channel technology or "type"
00807  * \return Returns 0 on success, -1 on failure.
00808  */
00809 int ast_channel_register(const struct ast_channel_tech *tech);
00810 
00811 /*! \brief Unregister a channel technology 
00812  * \param tech Structure defining channel technology or "type" that was previously registered
00813  * \return No return value.
00814  */
00815 void ast_channel_unregister(const struct ast_channel_tech *tech);
00816 
00817 /*! \brief Get a channel technology structure by name
00818  * \param name name of technology to find
00819  * \return a pointer to the structure, or NULL if no matching technology found
00820  */
00821 const struct ast_channel_tech *ast_get_channel_tech(const char *name);
00822 
00823 /*! \brief Hang up a channel  
00824  * \note This function performs a hard hangup on a channel.  Unlike the soft-hangup, this function
00825  * performs all stream stopping, etc, on the channel that needs to end.
00826  * chan is no longer valid after this call.
00827  * \param chan channel to hang up
00828  * \return Returns 0 on success, -1 on failure.
00829  */
00830 int ast_hangup(struct ast_channel *chan);
00831 
00832 /*! \brief Softly hangup up a channel 
00833  * \param chan channel to be soft-hung-up
00834  * Call the protocol layer, but don't destroy the channel structure (use this if you are trying to
00835  * safely hangup a channel managed by another thread.
00836  * \param reason an AST_SOFTHANGUP_* reason code
00837  * \return Returns 0 regardless
00838  */
00839 int ast_softhangup(struct ast_channel *chan, int cause);
00840 
00841 /*! \brief Softly hangup up a channel (no channel lock) 
00842  * \param chan channel to be soft-hung-up
00843  * \param reason an AST_SOFTHANGUP_* reason code */
00844 int ast_softhangup_nolock(struct ast_channel *chan, int cause);
00845 
00846 /*!
00847  * \brief Clear a set of softhangup flags from a channel
00848  *
00849  * Never clear a softhangup flag from a channel directly.  Instead,
00850  * use this function.  This ensures that all aspects of the softhangup
00851  * process are aborted.
00852  *
00853  * \param chan the channel to clear the flag on
00854  * \param flag the flag or flags to clear
00855  *
00856  * \return Nothing.
00857  */
00858 void ast_channel_clear_softhangup(struct ast_channel *chan, int flag);
00859 
00860 /*! \brief Check to see if a channel is needing hang up 
00861  * \param chan channel on which to check for hang up
00862  * This function determines if the channel is being requested to be hung up.
00863  * \return Returns 0 if not, or 1 if hang up is requested (including time-out).
00864  */
00865 int ast_check_hangup(struct ast_channel *chan);
00866 
00867 /*! \brief Compare a offset with the settings of when to hang a channel up 
00868  * \param chan channel on which to check for hang up
00869  * \param offset offset in seconds from current time
00870  * \return 1, 0, or -1
00871  * This function compares a offset from current time with the absolute time 
00872  * out on a channel (when to hang up). If the absolute time out on a channel
00873  * is earlier than current time plus the offset, it returns 1, if the two
00874  * time values are equal, it return 0, otherwise, it retturn -1.
00875  */
00876 int ast_channel_cmpwhentohangup(struct ast_channel *chan, time_t offset);
00877 
00878 /*! \brief Set when to hang a channel up 
00879  * \param chan channel on which to check for hang up
00880  * \param offset offset in seconds from current time of when to hang up
00881  * This function sets the absolute time out on a channel (when to hang up).
00882  */
00883 void ast_channel_setwhentohangup(struct ast_channel *chan, time_t offset);
00884 
00885 /*! \brief Answer a ringing call 
00886  * \param chan channel to answer
00887  * This function answers a channel and handles all necessary call
00888  * setup functions.
00889  * \return Returns 0 on success, -1 on failure
00890  */
00891 int ast_answer(struct ast_channel *chan);
00892 
00893 /*! \brief Make a call 
00894  * \param chan which channel to make the call on
00895  * \param addr destination of the call
00896  * \param timeout time to wait on for connect
00897  * Place a call, take no longer than timeout ms. 
00898    \return Returns -1 on failure, 0 on not enough time 
00899    (does not automatically stop ringing), and  
00900    the number of seconds the connect took otherwise.
00901    */
00902 int ast_call(struct ast_channel *chan, char *addr, int timeout);
00903 
00904 /*! \brief Indicates condition of channel 
00905  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
00906  * \param chan channel to change the indication
00907  * \param condition which condition to indicate on the channel
00908  * \return Returns 0 on success, -1 on failure
00909  */
00910 int ast_indicate(struct ast_channel *chan, int condition);
00911 
00912 /*! \brief Indicates condition of channel, with payload
00913  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
00914  * \param chan channel to change the indication
00915  * \param condition which condition to indicate on the channel
00916  * \param data pointer to payload data
00917  * \param datalen size of payload data
00918  * \return Returns 0 on success, -1 on failure
00919  */
00920 int ast_indicate_data(struct ast_channel *chan, int condition, const void *data, size_t datalen);
00921 
00922 /* Misc stuff ------------------------------------------------ */
00923 
00924 /*! \brief Wait for input on a channel 
00925  * \param chan channel to wait on
00926  * \param ms length of time to wait on the channel
00927  * Wait for input on a channel for a given # of milliseconds (<0 for indefinite). 
00928   \return Returns < 0 on  failure, 0 if nothing ever arrived, and the # of ms remaining otherwise */
00929 int ast_waitfor(struct ast_channel *chan, int ms);
00930 
00931 /*!
00932  * \brief Should we keep this frame for later?
00933  *
00934  * There are functions such as ast_safe_sleep which will
00935  * service a channel to ensure that it does not have a
00936  * large backlog of queued frames. When this happens,
00937  * we want to hold on to specific frame types and just drop
00938  * others. This function will tell if the frame we just
00939  * read should be held onto.
00940  *
00941  * \param frame The frame we just read
00942  * \retval 1 frame should be kept
00943  * \retval 0 frame should be dropped
00944  */
00945 int ast_is_deferrable_frame(const struct ast_frame *frame);
00946 
00947 /*! \brief Wait for a specied amount of time, looking for hangups 
00948  * \param chan channel to wait for
00949  * \param ms length of time in milliseconds to sleep
00950  * Waits for a specified amount of time, servicing the channel as required.
00951  * \return returns -1 on hangup, otherwise 0.
00952  */
00953 int ast_safe_sleep(struct ast_channel *chan, int ms);
00954 
00955 /*! \brief Wait for a specied amount of time, looking for hangups and a condition argument 
00956  * \param chan channel to wait for
00957  * \param ms length of time in milliseconds to sleep
00958  * \param cond a function pointer for testing continue condition
00959  * \param data argument to be passed to the condition test function
00960  * \return returns -1 on hangup, otherwise 0.
00961  * Waits for a specified amount of time, servicing the channel as required. If cond
00962  * returns 0, this function returns.
00963  */
00964 int ast_safe_sleep_conditional(struct ast_channel *chan, int ms, int (*cond)(void*), void *data );
00965 
00966 /*! \brief Waits for activity on a group of channels 
00967  * \param chan an array of pointers to channels
00968  * \param n number of channels that are to be waited upon
00969  * \param fds an array of fds to wait upon
00970  * \param nfds the number of fds to wait upon
00971  * \param exception exception flag
00972  * \param outfd fd that had activity on it
00973  * \param ms how long the wait was
00974  * Big momma function here.  Wait for activity on any of the n channels, or any of the nfds
00975    file descriptors.
00976    \return Returns the channel with activity, or NULL on error or if an FD
00977    came first.  If the FD came first, it will be returned in outfd, otherwise, outfd
00978    will be -1 */
00979 struct ast_channel *ast_waitfor_nandfds(struct ast_channel **chan, int n, int *fds, int nfds, int *exception, int *outfd, int *ms);
00980 
00981 /*! \brief Waits for input on a group of channels
00982    Wait for input on an array of channels for a given # of milliseconds. 
00983    \return Return channel with activity, or NULL if none has activity.  
00984    \param chan an array of pointers to channels
00985    \param n number of channels that are to be waited upon
00986    \param ms time "ms" is modified in-place, if applicable */
00987 struct ast_channel *ast_waitfor_n(struct ast_channel **chan, int n, int *ms);
00988 
00989 /*! \brief Waits for input on an fd
00990    This version works on fd's only.  Be careful with it. */
00991 int ast_waitfor_n_fd(int *fds, int n, int *ms, int *exception);
00992 
00993 
00994 /*! \brief Reads a frame
00995  * \param chan channel to read a frame from
00996    Read a frame.  
00997    \return Returns a frame, or NULL on error.  If it returns NULL, you
00998       best just stop reading frames and assume the channel has been
00999       disconnected. */
01000 struct ast_frame *ast_read(struct ast_channel *chan);
01001 
01002 /*! \brief Reads a frame, returning AST_FRAME_NULL frame if audio. 
01003  * Read a frame. 
01004    \param chan channel to read a frame from
01005    \return  Returns a frame, or NULL on error.  If it returns NULL, you
01006       best just stop reading frames and assume the channel has been
01007       disconnected.  
01008    \note Audio is replaced with AST_FRAME_NULL to avoid 
01009    transcode when the resulting audio is not necessary. */
01010 struct ast_frame *ast_read_noaudio(struct ast_channel *chan);
01011 
01012 /*! \brief Write a frame to a channel 
01013  * This function writes the given frame to the indicated channel.
01014  * \param chan destination channel of the frame
01015  * \param frame frame that will be written
01016  * \return It returns 0 on success, -1 on failure.
01017  */
01018 int ast_write(struct ast_channel *chan, struct ast_frame *frame);
01019 
01020 /*! \brief Write video frame to a channel 
01021  * This function writes the given frame to the indicated channel.
01022  * \param chan destination channel of the frame
01023  * \param frame frame that will be written
01024  * \return It returns 1 on success, 0 if not implemented, and -1 on failure.
01025  */
01026 int ast_write_video(struct ast_channel *chan, struct ast_frame *frame);
01027 
01028 /*! \brief Send empty audio to prime a channel driver */
01029 int ast_prod(struct ast_channel *chan);
01030 
01031 /*! \brief Sets read format on channel chan
01032  * Set read format for channel to whichever component of "format" is best. 
01033  * \param chan channel to change
01034  * \param format format to change to
01035  * \return Returns 0 on success, -1 on failure
01036  */
01037 int ast_set_read_format(struct ast_channel *chan, int format);
01038 
01039 /*! \brief Sets write format on channel chan
01040  * Set write format for channel to whichever compoent of "format" is best. 
01041  * \param chan channel to change
01042  * \param format new format for writing
01043  * \return Returns 0 on success, -1 on failure
01044  */
01045 int ast_set_write_format(struct ast_channel *chan, int format);
01046 
01047 /*! \brief Sends text to a channel 
01048  * Write text to a display on a channel
01049  * \param chan channel to act upon
01050  * \param text string of text to send on the channel
01051  * \return Returns 0 on success, -1 on failure
01052  */
01053 int ast_sendtext(struct ast_channel *chan, const char *text);
01054 
01055 /*! \brief Receives a text character from a channel
01056  * \param chan channel to act upon
01057  * \param timeout timeout in milliseconds (0 for infinite wait)
01058  * Read a char of text from a channel
01059  * Returns 0 on success, -1 on failure
01060  */
01061 int ast_recvchar(struct ast_channel *chan, int timeout);
01062 
01063 /*! \brief Send a DTMF digit to a channel
01064  * Send a DTMF digit to a channel.
01065  * \param chan channel to act upon
01066  * \param digit the DTMF digit to send, encoded in ASCII
01067  * \return Returns 0 on success, -1 on failure
01068  */
01069 int ast_senddigit(struct ast_channel *chan, char digit);
01070 
01071 int ast_senddigit_begin(struct ast_channel *chan, char digit);
01072 int ast_senddigit_end(struct ast_channel *chan, char digit, unsigned int duration);
01073 
01074 /*! \brief Receives a text string from a channel
01075  * Read a string of text from a channel
01076  * \param chan channel to act upon
01077  * \param timeout timeout in milliseconds (0 for infinite wait)
01078  * \return the received text, or NULL to signify failure.
01079  */
01080 char *ast_recvtext(struct ast_channel *chan, int timeout);
01081 
01082 /*! \brief Browse channels in use
01083  * Browse the channels currently in use 
01084  * \param prev where you want to start in the channel list
01085  * \return Returns the next channel in the list, NULL on end.
01086  *    If it returns a channel, that channel *has been locked*!
01087  */
01088 struct ast_channel *ast_channel_walk_locked(const struct ast_channel *prev);
01089 
01090 /*! \brief Get channel by name (locks channel) */
01091 struct ast_channel *ast_get_channel_by_name_locked(const char *chan);
01092 
01093 /*! \brief Get channel by name prefix (locks channel) */
01094 struct ast_channel *ast_get_channel_by_name_prefix_locked(const char *name, const int namelen);
01095 
01096 /*! \brief Get channel by name prefix (locks channel) */
01097 struct ast_channel *ast_walk_channel_by_name_prefix_locked(const struct ast_channel *chan, const char *name, const int namelen);
01098 
01099 /*! \brief Get channel by exten (and optionally context) and lock it */
01100 struct ast_channel *ast_get_channel_by_exten_locked(const char *exten, const char *context);
01101 
01102 /*! \brief Get next channel by exten (and optionally context) and lock it */
01103 struct ast_channel *ast_walk_channel_by_exten_locked(const struct ast_channel *chan, const char *exten,
01104                        const char *context);
01105 
01106 /*! ! \brief Waits for a digit
01107  * \param c channel to wait for a digit on
01108  * \param ms how many milliseconds to wait
01109  * \return Returns <0 on error, 0 on no entry, and the digit on success. */
01110 int ast_waitfordigit(struct ast_channel *c, int ms);
01111 
01112 /*! \brief Wait for a digit
01113  Same as ast_waitfordigit() with audio fd for outputting read audio and ctrlfd to monitor for reading. 
01114  * \param c channel to wait for a digit on
01115  * \param ms how many milliseconds to wait
01116  * \param audiofd audio file descriptor to write to if audio frames are received
01117  * \param ctrlfd control file descriptor to monitor for reading
01118  * \return Returns 1 if ctrlfd becomes available */
01119 int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int ctrlfd);
01120 
01121 /*! Reads multiple digits 
01122  * \param c channel to read from
01123  * \param s string to read in to.  Must be at least the size of your length
01124  * \param len how many digits to read (maximum)
01125  * \param timeout how long to timeout between digits
01126  * \param rtimeout timeout to wait on the first digit
01127  * \param enders digits to end the string
01128  * Read in a digit string "s", max length "len", maximum timeout between 
01129    digits "timeout" (-1 for none), terminated by anything in "enders".  Give them rtimeout
01130    for the first digit.  Returns 0 on normal return, or 1 on a timeout.  In the case of
01131    a timeout, any digits that were read before the timeout will still be available in s.  
01132    RETURNS 2 in full version when ctrlfd is available, NOT 1*/
01133 int ast_readstring(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders);
01134 int ast_readstring_full(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders, int audiofd, int ctrlfd);
01135 
01136 /*! \brief Report DTMF on channel 0 */
01137 #define AST_BRIDGE_DTMF_CHANNEL_0      (1 << 0)    
01138 /*! \brief Report DTMF on channel 1 */
01139 #define AST_BRIDGE_DTMF_CHANNEL_1      (1 << 1)    
01140 /*! \brief Return all voice frames on channel 0 */
01141 #define AST_BRIDGE_REC_CHANNEL_0    (1 << 2)    
01142 /*! \brief Return all voice frames on channel 1 */
01143 #define AST_BRIDGE_REC_CHANNEL_1    (1 << 3)    
01144 /*! \brief Ignore all signal frames except NULL */
01145 #define AST_BRIDGE_IGNORE_SIGS         (1 << 4)    
01146 
01147 
01148 /*! \brief Makes two channel formats compatible 
01149  * \param c0 first channel to make compatible
01150  * \param c1 other channel to make compatible
01151  * Set two channels to compatible formats -- call before ast_channel_bridge in general .  
01152  * \return Returns 0 on success and -1 if it could not be done */
01153 int ast_channel_make_compatible(struct ast_channel *c0, struct ast_channel *c1);
01154 
01155 /*! Bridge two channels together 
01156  * \param c0 first channel to bridge
01157  * \param c1 second channel to bridge
01158  * \param config config for the channels
01159  * \param fo destination frame(?)
01160  * \param rc destination channel(?)
01161  * Bridge two channels (c0 and c1) together.  If an important frame occurs, we return that frame in
01162    *rf (remember, it could be NULL) and which channel (0 or 1) in rc */
01163 /* int ast_channel_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc); */
01164 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);
01165 
01166 /*! \brief Weird function made for call transfers
01167  * \param original channel to make a copy of
01168  * \param clone copy of the original channel
01169  * This is a very strange and freaky function used primarily for transfer.  Suppose that
01170    "original" and "clone" are two channels in random situations.  This function takes
01171    the guts out of "clone" and puts them into the "original" channel, then alerts the
01172    channel driver of the change, asking it to fixup any private information (like the
01173    p->owner pointer) that is affected by the change.  The physical layer of the original
01174    channel is hung up.  */
01175 int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clone);
01176 
01177 /*! Gives the string form of a given cause code */
01178 /*! 
01179  * \param state cause to get the description of
01180  * Give a name to a cause code
01181  * Returns the text form of the binary cause code given
01182  */
01183 const char *ast_cause2str(int state) attribute_pure;
01184 
01185 /*! Convert the string form of a cause code to a number */
01186 /*! 
01187  * \param name string form of the cause
01188  * Returns the cause code
01189  */
01190 int ast_str2cause(const char *name) attribute_pure;
01191 
01192 /*! Gives the string form of a given channel state */
01193 /*! 
01194  * \param ast_channel_state state to get the name of
01195  * Give a name to a state 
01196  * Returns the text form of the binary state given
01197  */
01198 char *ast_state2str(enum ast_channel_state);
01199 
01200 /*! Gives the string form of a given transfer capability */
01201 /*!
01202  * \param transfercapability transfercapabilty to get the name of
01203  * Give a name to a transfercapbility
01204  * See above
01205  * Returns the text form of the binary transfer capbility
01206  */
01207 char *ast_transfercapability2str(int transfercapability) attribute_const;
01208 
01209 /* Options: Some low-level drivers may implement "options" allowing fine tuning of the
01210    low level channel.  See frame.h for options.  Note that many channel drivers may support
01211    none or a subset of those features, and you should not count on this if you want your
01212    asterisk application to be portable.  They're mainly useful for tweaking performance */
01213 
01214 /*! Sets an option on a channel */
01215 /*! 
01216  * \param channel channel to set options on
01217  * \param option option to change
01218  * \param data data specific to option
01219  * \param datalen length of the data
01220  * \param block blocking or not
01221  * Set an option on a channel (see frame.h), optionally blocking awaiting the reply 
01222  * Returns 0 on success and -1 on failure
01223  */
01224 int ast_channel_setoption(struct ast_channel *channel, int option, void *data, int datalen, int block);
01225 
01226 /*! Pick the best codec  */
01227 /* Choose the best codec...  Uhhh...   Yah. */
01228 int ast_best_codec(int fmts);
01229 
01230 
01231 /*! Checks the value of an option */
01232 /*! 
01233  * Query the value of an option, optionally blocking until a reply is received
01234  * Works similarly to setoption except only reads the options.
01235  */
01236 struct ast_frame *ast_channel_queryoption(struct ast_channel *channel, int option, void *data, int *datalen, int block);
01237 
01238 /*! Checks for HTML support on a channel */
01239 /*! Returns 0 if channel does not support HTML or non-zero if it does */
01240 int ast_channel_supports_html(struct ast_channel *channel);
01241 
01242 /*! Sends HTML on given channel */
01243 /*! Send HTML or URL on link.  Returns 0 on success or -1 on failure */
01244 int ast_channel_sendhtml(struct ast_channel *channel, int subclass, const char *data, int datalen);
01245 
01246 /*! Sends a URL on a given link */
01247 /*! Send URL on link.  Returns 0 on success or -1 on failure */
01248 int ast_channel_sendurl(struct ast_channel *channel, const char *url);
01249 
01250 /*! Defers DTMF */
01251 /*! Defer DTMF so that you only read things like hangups and audio.  Returns
01252    non-zero if channel was already DTMF-deferred or 0 if channel is just now
01253    being DTMF-deferred */
01254 int ast_channel_defer_dtmf(struct ast_channel *chan);
01255 
01256 /*! Undeos a defer */
01257 /*! Undo defer.  ast_read will return any dtmf characters that were queued */
01258 void ast_channel_undefer_dtmf(struct ast_channel *chan);
01259 
01260 /*! Initiate system shutdown -- prevents new channels from being allocated.
01261     If "hangup" is non-zero, all existing channels will receive soft
01262      hangups */
01263 void ast_begin_shutdown(int hangup);
01264 
01265 /*! Cancels an existing shutdown and returns to normal operation */
01266 void ast_cancel_shutdown(void);
01267 
01268 /*! Returns number of active/allocated channels */
01269 int ast_active_channels(void);
01270 
01271 /*! Returns non-zero if Asterisk is being shut down */
01272 int ast_shutting_down(void);
01273 
01274 /*! Activate a given generator */
01275 int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params);
01276 
01277 /*! Deactive an active generator */
01278 void ast_deactivate_generator(struct ast_channel *chan);
01279 
01280 /*!
01281  * \note The channel does not need to be locked before calling this function.
01282  */
01283 void ast_set_callerid(struct ast_channel *chan, const char *cidnum, const char *cidname, const char *ani);
01284 
01285 
01286 /*! return a mallocd string with the result of sprintf of the fmt and following args */
01287 char __attribute__((format(printf, 1, 2))) *ast_safe_string_alloc(const char *fmt, ...);
01288 
01289 
01290 /*! Start a tone going */
01291 int ast_tonepair_start(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01292 /*! Stop a tone from playing */
01293 void ast_tonepair_stop(struct ast_channel *chan);
01294 /*! Play a tone pair for a given amount of time */
01295 int ast_tonepair(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01296 
01297 /*!
01298  * \brief Automatically service a channel for us... 
01299  *
01300  * \retval 0 success
01301  * \retval -1 failure, or the channel is already being autoserviced
01302  */
01303 int ast_autoservice_start(struct ast_channel *chan);
01304 
01305 /*! 
01306  * \brief Stop servicing a channel for us...  
01307  *
01308  * \note if chan is locked prior to calling ast_autoservice_stop, it
01309  * is likely that there will be a deadlock between the thread that calls
01310  * ast_autoservice_stop and the autoservice thread. It is important
01311  * that chan is not locked prior to this call
01312  *
01313  * \retval 0 success
01314  * \retval -1 error, or the channel has been hungup 
01315  */
01316 int ast_autoservice_stop(struct ast_channel *chan);
01317 
01318 /*!
01319  * \brief Ignore certain frame types
01320  * \note Normally, we cache DTMF, IMAGE, HTML, TEXT, and CONTROL frames
01321  * while a channel is in autoservice and queue them up when taken out of
01322  * autoservice.  When this is not desireable, this API may be used to
01323  * cause the channel to ignore those frametypes after the channel is put
01324  * into autoservice, but before autoservice is stopped.
01325  * \retval 0 success
01326  * \retval -1 channel is not in autoservice
01327  */
01328 int ast_autoservice_ignore(struct ast_channel *chan, enum ast_frame_type ftype);
01329 
01330 /* If built with DAHDI optimizations, force a scheduled expiration on the
01331    timer fd, at which point we call the callback function / data */
01332 int ast_settimeout(struct ast_channel *c, int samples, int (*func)(const void *data), void *data);
01333 
01334 /*!   \brief Transfer a channel (if supported).  Returns -1 on error, 0 if not supported
01335    and 1 if supported and requested 
01336    \param chan current channel
01337    \param dest destination extension for transfer
01338 */
01339 int ast_transfer(struct ast_channel *chan, char *dest);
01340 
01341 /*!   \brief  Start masquerading a channel
01342    XXX This is a seriously wacked out operation.  We're essentially putting the guts of
01343            the clone channel into the original channel.  Start by killing off the original
01344            channel's backend.   I'm not sure we're going to keep this function, because
01345            while the features are nice, the cost is very high in terms of pure nastiness. XXX
01346    \param chan    Channel to masquerade
01347 */
01348 int ast_do_masquerade(struct ast_channel *chan);
01349 
01350 /*!   \brief Find bridged channel 
01351    \param chan Current channel
01352 */
01353 struct ast_channel *ast_bridged_channel(struct ast_channel *chan);
01354 
01355 /*!
01356   \brief Inherits channel variable from parent to child channel
01357   \param parent Parent channel
01358   \param child Child channel
01359 
01360   Scans all channel variables in the parent channel, looking for those
01361   that should be copied into the child channel.
01362   Variables whose names begin with a single '_' are copied into the
01363   child channel with the prefix removed.
01364   Variables whose names begin with '__' are copied into the child
01365   channel with their names unchanged.
01366 */
01367 void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child);
01368 
01369 /*!
01370   \brief adds a list of channel variables to a channel
01371   \param chan the channel
01372   \param vars a linked list of variables
01373 
01374   Variable names can be for a regular channel variable or a dialplan function
01375   that has the ability to be written to.
01376 */
01377 void ast_set_variables(struct ast_channel *chan, struct ast_variable *vars);
01378 
01379 /*!
01380   \brief An opaque 'object' structure use by silence generators on channels.
01381  */
01382 struct ast_silence_generator;
01383 
01384 /*!
01385   \brief Starts a silence generator on the given channel.
01386   \param chan The channel to generate silence on
01387   \return An ast_silence_generator pointer, or NULL if an error occurs
01388 
01389   This function will cause SLINEAR silence to be generated on the supplied
01390   channel until it is disabled; if the channel cannot be put into SLINEAR
01391   mode then the function will fail.
01392 
01393   The pointer returned by this function must be preserved and passed to
01394   ast_channel_stop_silence_generator when you wish to stop the silence
01395   generation.
01396  */
01397 struct ast_silence_generator *ast_channel_start_silence_generator(struct ast_channel *chan);
01398 
01399 /*!
01400   \brief Stops a previously-started silence generator on the given channel.
01401   \param chan The channel to operate on
01402   \param state The ast_silence_generator pointer return by a previous call to
01403   ast_channel_start_silence_generator.
01404   \return nothing
01405 
01406   This function will stop the operating silence generator and return the channel
01407   to its previous write format.
01408  */
01409 void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state);
01410 
01411 /*!
01412   \brief Check if the channel can run in internal timing mode.
01413   \param chan The channel to check
01414   \return boolean
01415 
01416   This function will return 1 if internal timing is enabled and the timing
01417   device is available.
01418  */
01419 int ast_internal_timing_enabled(struct ast_channel *chan);
01420 
01421 /* Misc. functions below */
01422 
01423 /*! \brief if fd is a valid descriptor, set *pfd with the descriptor
01424  * \return Return 1 (not -1!) if added, 0 otherwise (so we can add the
01425  * return value to the index into the array)
01426  */
01427 static inline int ast_add_fd(struct pollfd *pfd, int fd)
01428 {
01429    pfd->fd = fd;
01430    pfd->events = POLLIN | POLLPRI;
01431    return fd >= 0;
01432 }
01433 
01434 /*! \brief Helper function for migrating select to poll */
01435 static inline int ast_fdisset(struct pollfd *pfds, int fd, int max, int *start)
01436 {
01437    int x;
01438    int dummy=0;
01439 
01440    if (fd < 0)
01441       return 0;
01442    if (!start)
01443       start = &dummy;
01444    for (x = *start; x<max; x++)
01445       if (pfds[x].fd == fd) {
01446          if (x == *start)
01447             (*start)++;
01448          return pfds[x].revents;
01449       }
01450    return 0;
01451 }
01452 
01453 #define CHECK_BLOCKING(c) do {    \
01454    if (ast_test_flag(c, AST_FLAG_BLOCKING)) {\
01455       if (option_debug) \
01456          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); \
01457    } else { \
01458       (c)->blocker = pthread_self(); \
01459       (c)->blockproc = __PRETTY_FUNCTION__; \
01460       ast_set_flag(c, AST_FLAG_BLOCKING); \
01461    } } while (0)
01462 
01463 ast_group_t ast_get_group(const char *s);
01464 
01465 /*! \brief print call- and pickup groups into buffer */
01466 char *ast_print_group(char *buf, int buflen, ast_group_t group);
01467 
01468 /*! \brief Convert enum channelreloadreason to text string for manager event
01469    \param reason  Enum channelreloadreason - reason for reload (manager, cli, start etc)
01470 */
01471 const char *channelreloadreason2txt(enum channelreloadreason reason);
01472 
01473 /*! \brief return an ast_variable list of channeltypes */
01474 struct ast_variable *ast_channeltype_list(void);
01475 
01476 /*!
01477   \brief Begin 'whispering' onto a channel
01478   \param chan The channel to whisper onto
01479   \return 0 for success, non-zero for failure
01480 
01481   This function will add a whisper buffer onto a channel and set a flag
01482   causing writes to the channel to reduce the volume level of the written
01483   audio samples, and then to mix in audio from the whisper buffer if it
01484   is available.
01485 
01486   Note: This function performs no locking; you must hold the channel's lock before
01487   calling this function.
01488  */
01489 int ast_channel_whisper_start(struct ast_channel *chan);
01490 
01491 /*!
01492   \brief Feed an audio frame into the whisper buffer on a channel
01493   \param chan The channel to whisper onto
01494   \param f The frame to to whisper onto chan
01495   \return 0 for success, non-zero for failure
01496  */
01497 int ast_channel_whisper_feed(struct ast_channel *chan, struct ast_frame *f);
01498 
01499 /*!
01500   \brief Stop 'whispering' onto a channel
01501   \param chan The channel to whisper onto
01502   \return 0 for success, non-zero for failure
01503 
01504   Note: This function performs no locking; you must hold the channel's lock before
01505   calling this function.
01506  */
01507 void ast_channel_whisper_stop(struct ast_channel *chan);
01508 
01509 
01510 
01511 /*!
01512   \brief return an english explanation of the code returned thru __ast_request_and_dial's 'outstate' argument
01513   \param reason  The integer argument, usually taken from AST_CONTROL_ macros
01514   \return char pointer explaining the code
01515  */
01516 char *ast_channel_reason2str(int reason);
01517 
01518 /*!
01519  * \brief Reload genericplc configuration value from codecs.conf
01520  *
01521  * Implementation is in main/channel.c
01522  */
01523 int ast_plc_reload(void);
01524 
01525 #if defined(__cplusplus) || defined(c_plusplus)
01526 }
01527 #endif
01528 
01529 #endif /* _ASTERISK_CHANNEL_H */

Generated on Thu Oct 11 06:42:06 2012 for Asterisk - the Open Source PBX by  doxygen 1.5.6