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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 /*! \page AstFileDesc File descriptors 
00088    Asterisk File descriptors are connected to each channel (see \ref Def_Channel)
00089    in the \ref ast_channel structure.
00090 */
00091 
00092 #ifndef _ASTERISK_CHANNEL_H
00093 #define _ASTERISK_CHANNEL_H
00094 
00095 #include "asterisk/abstract_jb.h"
00096 
00097 #include <unistd.h>
00098 #ifdef POLLCOMPAT 
00099 #include "asterisk/poll-compat.h"
00100 #else
00101 #include <sys/poll.h>
00102 #endif
00103 
00104 #if defined(__cplusplus) || defined(c_plusplus)
00105 extern "C" {
00106 #endif
00107 
00108 #define AST_MAX_EXTENSION  80 /*!< Max length of an extension */
00109 #define AST_MAX_CONTEXT    80 /*!< Max length of a context */
00110 #define AST_CHANNEL_NAME   80 /*!< Max length of an ast_channel name */
00111 #define MAX_LANGUAGE    20 /*!< Max length of the language setting */
00112 #define MAX_MUSICCLASS     80 /*!< Max length of the music class setting */
00113 
00114 #include "asterisk/compat.h"
00115 #include "asterisk/frame.h"
00116 #include "asterisk/sched.h"
00117 #include "asterisk/chanvars.h"
00118 #include "asterisk/config.h"
00119 #include "asterisk/lock.h"
00120 #include "asterisk/cdr.h"
00121 #include "asterisk/utils.h"
00122 #include "asterisk/linkedlists.h"
00123 #include "asterisk/stringfields.h"
00124 #include "asterisk/options.h"
00125 #include "asterisk/strings.h"
00126 #include "asterisk/compiler.h"
00127 
00128 #define DATASTORE_INHERIT_FOREVER   INT_MAX
00129 
00130 #define AST_MAX_FDS     8
00131 /*
00132  * We have AST_MAX_FDS file descriptors in a channel.
00133  * Some of them have a fixed use:
00134  */
00135 #define AST_ALERT_FD (AST_MAX_FDS-1)      /*!< used for alertpipe */
00136 #define AST_TIMING_FD   (AST_MAX_FDS-2)      /*!< used for timingfd */
00137 #define AST_AGENT_FD (AST_MAX_FDS-3)      /*!< used by agents for pass through */
00138 #define AST_GENERATOR_FD   (AST_MAX_FDS-4)   /*!< used by generator */
00139 
00140 enum ast_bridge_result {
00141    AST_BRIDGE_COMPLETE = 0,
00142    AST_BRIDGE_FAILED = -1,
00143    AST_BRIDGE_FAILED_NOWARN = -2,
00144    AST_BRIDGE_RETRY = -3,
00145 };
00146 
00147 typedef unsigned long long ast_group_t;
00148 
00149 /*! \todo Add an explanation of an Asterisk generator 
00150 */
00151 struct ast_generator {
00152    void *(*alloc)(struct ast_channel *chan, void *params);
00153    void (*release)(struct ast_channel *chan, void *data);
00154    /*! This function gets called with the channel unlocked, but is called in
00155     *  the context of the channel thread so we know the channel is not going
00156     *  to disappear.  This callback is responsible for locking the channel as
00157     *  necessary. */
00158    int (*generate)(struct ast_channel *chan, void *data, int len, int samples);
00159 };
00160 
00161 /*! \brief Structure for a data store type */
00162 struct ast_datastore_info {
00163    const char *type;    /*!< Type of data store */
00164    void *(*duplicate)(void *data); /*!< Duplicate item data (used for inheritance) */
00165    void (*destroy)(void *data);  /*!< Destroy function */
00166    /*!
00167     * \brief Fix up channel references
00168     *
00169     * \arg data The datastore data
00170     * \arg old_chan The old channel owning the datastore
00171     * \arg new_chan The new channel owning the datastore
00172     *
00173     * This is exactly like the fixup callback of the channel technology interface.
00174     * It allows a datastore to fix any pointers it saved to the owning channel
00175     * in case that the owning channel has changed.  Generally, this would happen
00176     * when the datastore is set to be inherited, and a masquerade occurs.
00177     *
00178     * \return nothing.
00179     */
00180    void (*chan_fixup)(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan);
00181 };
00182 
00183 /*! \brief Structure for a channel data store */
00184 struct ast_datastore {
00185    char *uid;     /*!< Unique data store identifier */
00186    void *data;    /*!< Contained data */
00187    const struct ast_datastore_info *info; /*!< Data store type information */
00188    unsigned int inheritance;  /*!Number of levels this item will continue to be inherited */
00189    AST_LIST_ENTRY(ast_datastore) entry; /*!< Used for easy linking */
00190 };
00191 
00192 /*! \brief Structure for all kinds of caller ID identifications.
00193  * \note All string fields here are malloc'ed, so they need to be
00194  * freed when the structure is deleted.
00195  * Also, NULL and "" must be considered equivalent.
00196  */
00197 struct ast_callerid {
00198    char *cid_dnid;      /*!< Malloc'd Dialed Number Identifier */
00199    char *cid_num;    /*!< Malloc'd Caller Number */
00200    char *cid_name;      /*!< Malloc'd Caller Name */
00201    char *cid_ani;    /*!< Malloc'd ANI */
00202    char *cid_rdnis;  /*!< Malloc'd RDNIS */
00203    int cid_pres;     /*!< Callerid presentation/screening */
00204    int cid_ani2;     /*!< Callerid ANI 2 (Info digits) */
00205    int cid_ton;      /*!< Callerid Type of Number */
00206    int cid_tns;      /*!< Callerid Transit Network Select */
00207 };
00208 
00209 /*! \brief 
00210    Structure to describe a channel "technology", ie a channel driver 
00211    See for examples:
00212    \arg chan_iax2.c - The Inter-Asterisk exchange protocol
00213    \arg chan_sip.c - The SIP channel driver
00214    \arg chan_zap.c - PSTN connectivity (TDM, PRI, T1/E1, FXO, FXS)
00215 
00216    If you develop your own channel driver, this is where you
00217    tell the PBX at registration of your driver what properties
00218    this driver supports and where different callbacks are 
00219    implemented.
00220 */
00221 struct ast_channel_tech {
00222    const char * const type;
00223    const char * const description;
00224 
00225    int capabilities;    /*!< Bitmap of formats this channel can handle */
00226 
00227    int properties;         /*!< Technology Properties */
00228 
00229    /*! \brief Requester - to set up call data structures (pvt's) */
00230    struct ast_channel *(* const requester)(const char *type, int format, void *data, int *cause);
00231 
00232    int (* const devicestate)(void *data); /*!< Devicestate call back */
00233 
00234    /*! \brief Start sending a literal DTMF digit */
00235    int (* const send_digit_begin)(struct ast_channel *chan, char digit);
00236 
00237    /*! \brief Stop sending a literal DTMF digit */
00238    int (* const send_digit_end)(struct ast_channel *chan, char digit, unsigned int duration);
00239 
00240    /*! \brief Call a given phone number (address, etc), but don't
00241       take longer than timeout seconds to do so.  */
00242    int (* const call)(struct ast_channel *chan, char *addr, int timeout);
00243 
00244    /*! \brief Hangup (and possibly destroy) the channel */
00245    int (* const hangup)(struct ast_channel *chan);
00246 
00247    /*! \brief Answer the channel */
00248    int (* const answer)(struct ast_channel *chan);
00249 
00250    /*! \brief Read a frame, in standard format (see frame.h) */
00251    struct ast_frame * (* const read)(struct ast_channel *chan);
00252 
00253    /*! \brief Write a frame, in standard format (see frame.h) */
00254    int (* const write)(struct ast_channel *chan, struct ast_frame *frame);
00255 
00256    /*! \brief Display or transmit text */
00257    int (* const send_text)(struct ast_channel *chan, const char *text);
00258 
00259    /*! \brief Display or send an image */
00260    int (* const send_image)(struct ast_channel *chan, struct ast_frame *frame);
00261 
00262    /*! \brief Send HTML data */
00263    int (* const send_html)(struct ast_channel *chan, int subclass, const char *data, int len);
00264 
00265    /*! \brief Handle an exception, reading a frame */
00266    struct ast_frame * (* const exception)(struct ast_channel *chan);
00267 
00268    /*! \brief Bridge two channels of the same type together */
00269    enum ast_bridge_result (* const bridge)(struct ast_channel *c0, struct ast_channel *c1, int flags,
00270                   struct ast_frame **fo, struct ast_channel **rc, int timeoutms);
00271 
00272    /*! \brief Indicate a particular condition (e.g. AST_CONTROL_BUSY or AST_CONTROL_RINGING or AST_CONTROL_CONGESTION */
00273    int (* const indicate)(struct ast_channel *c, int condition, const void *data, size_t datalen);
00274 
00275    /*! \brief Fix up a channel:  If a channel is consumed, this is called.  Basically update any ->owner links */
00276    int (* const fixup)(struct ast_channel *oldchan, struct ast_channel *newchan);
00277 
00278    /*! \brief Set a given option */
00279    int (* const setoption)(struct ast_channel *chan, int option, void *data, int datalen);
00280 
00281    /*! \brief Query a given option */
00282    int (* const queryoption)(struct ast_channel *chan, int option, void *data, int *datalen);
00283 
00284    /*! \brief Blind transfer other side (see app_transfer.c and ast_transfer() */
00285    int (* const transfer)(struct ast_channel *chan, const char *newdest);
00286 
00287    /*! \brief Write a frame, in standard format */
00288    int (* const write_video)(struct ast_channel *chan, struct ast_frame *frame);
00289 
00290    /*! \brief Find bridged channel */
00291    struct ast_channel *(* const bridged_channel)(struct ast_channel *chan, struct ast_channel *bridge);
00292 
00293    /*! \brief Provide additional read items for CHANNEL() dialplan function */
00294    int (* func_channel_read)(struct ast_channel *chan, char *function, char *data, char *buf, size_t len);
00295 
00296    /*! \brief Provide additional write items for CHANNEL() dialplan function */
00297    int (* func_channel_write)(struct ast_channel *chan, char *function, char *data, const char *value);
00298 
00299    /*! \brief Retrieve base channel (agent and local) */
00300    struct ast_channel* (* get_base_channel)(struct ast_channel *chan);
00301    
00302    /*! \brief Set base channel (agent and local) */
00303    int (* set_base_channel)(struct ast_channel *chan, struct ast_channel *base);
00304 };
00305 
00306 #define  DEBUGCHAN_FLAG  0x80000000
00307 #define  FRAMECOUNT_INC(x) ( ((x) & DEBUGCHAN_FLAG) | (((x)+1) & ~DEBUGCHAN_FLAG) )
00308 
00309 enum ast_channel_adsicpe {
00310    AST_ADSI_UNKNOWN,
00311    AST_ADSI_AVAILABLE,
00312    AST_ADSI_UNAVAILABLE,
00313    AST_ADSI_OFFHOOKONLY,
00314 };
00315 
00316 /*! 
00317  * \brief ast_channel states
00318  *
00319  * \note Bits 0-15 of state are reserved for the state (up/down) of the line
00320  *       Bits 16-32 of state are reserved for flags
00321  */
00322 enum ast_channel_state {
00323    /*! Channel is down and available */
00324    AST_STATE_DOWN,
00325    /*! Channel is down, but reserved */
00326    AST_STATE_RESERVED,
00327    /*! Channel is off hook */
00328    AST_STATE_OFFHOOK,
00329    /*! Digits (or equivalent) have been dialed */
00330    AST_STATE_DIALING,
00331    /*! Line is ringing */
00332    AST_STATE_RING,
00333    /*! Remote end is ringing */
00334    AST_STATE_RINGING,
00335    /*! Line is up */
00336    AST_STATE_UP,
00337    /*! Line is busy */
00338    AST_STATE_BUSY,
00339    /*! Digits (or equivalent) have been dialed while offhook */
00340    AST_STATE_DIALING_OFFHOOK,
00341    /*! Channel has detected an incoming call and is waiting for ring */
00342    AST_STATE_PRERING,
00343 
00344    /*! Do not transmit voice data */
00345    AST_STATE_MUTE = (1 << 16),
00346 };
00347 
00348 /*! \brief Main Channel structure associated with a channel. 
00349  * This is the side of it mostly used by the pbx and call management.
00350  *
00351  * \note XXX It is important to remember to increment .cleancount each time
00352  *       this structure is changed. XXX
00353  */
00354 struct ast_channel {
00355    /*! \brief Technology (point to channel driver) */
00356    const struct ast_channel_tech *tech;
00357 
00358    /*! \brief Private data used by the technology driver */
00359    void *tech_pvt;
00360 
00361    AST_DECLARE_STRING_FIELDS(
00362       AST_STRING_FIELD(name);       /*!< ASCII unique channel name */
00363       AST_STRING_FIELD(language);      /*!< Language requested for voice prompts */
00364       AST_STRING_FIELD(musicclass);    /*!< Default music class */
00365       AST_STRING_FIELD(accountcode);      /*!< Account code for billing */
00366       AST_STRING_FIELD(call_forward);     /*!< Where to forward to if asked to dial on this interface */
00367       AST_STRING_FIELD(uniqueid);      /*!< Unique Channel Identifier */
00368    );
00369    
00370    /*! \brief File descriptor for channel -- Drivers will poll on these file descriptors, so at least one must be non -1.  See \ref AstFileDesc */
00371    int fds[AST_MAX_FDS];   
00372 
00373    void *music_state;            /*!< Music State*/
00374    void *generatordata;          /*!< Current generator data if there is any */
00375    struct ast_generator *generator;    /*!< Current active data generator */
00376 
00377    /*! \brief Who are we bridged to, if we're bridged. Who is proxying for us,
00378      if we are proxied (i.e. chan_agent).
00379      Do not access directly, use ast_bridged_channel(chan) */
00380    struct ast_channel *_bridge;
00381    struct ast_channel *masq;        /*!< Channel that will masquerade as us */
00382    struct ast_channel *masqr;       /*!< Who we are masquerading as */
00383    int cdrflags;              /*!< Call Detail Record Flags */
00384 
00385    int _softhangup;           /*!< Whether or not we have been hung up...  Do not set this value
00386                            directly, use ast_softhangup() */
00387    time_t   whentohangup;           /*!< Non-zero, set to actual time when channel is to be hung up */
00388    pthread_t blocker;            /*!< If anyone is blocking, this is them */
00389    ast_mutex_t lock;          /*!< Lock, can be used to lock a channel for some operations - see ast_channel_lock() */
00390    const char *blockproc;           /*!< Procedure causing blocking */
00391 
00392    const char *appl;          /*!< Current application */
00393    const char *data;          /*!< Data passed to current application */
00394    int fdno;               /*!< Which fd had an event detected on */
00395    struct sched_context *sched;        /*!< Schedule context */
00396    int streamid;              /*!< For streaming playback, the schedule ID */
00397    struct ast_filestream *stream;         /*!< Stream itself. */
00398    int vstreamid;             /*!< For streaming video playback, the schedule ID */
00399    struct ast_filestream *vstream;        /*!< Video Stream itself. */
00400    int oldwriteformat;           /*!< Original writer format */
00401    
00402    int timingfd;              /*!< Timing fd */
00403    int (*timingfunc)(const void *data);
00404    void *timingdata;
00405 
00406    enum ast_channel_state _state;         /*!< State of line -- Don't write directly, use ast_setstate() */
00407    int rings;              /*!< Number of rings so far */
00408    struct ast_callerid cid;         /*!< Caller ID, name, presentation etc */
00409    char dtmfq[AST_MAX_EXTENSION];         /*!< Any/all queued DTMF characters */
00410    struct ast_frame dtmff;          /*!< DTMF frame */
00411 
00412    char context[AST_MAX_CONTEXT];         /*!< Dialplan: Current extension context */
00413    char exten[AST_MAX_EXTENSION];         /*!< Dialplan: Current extension number */
00414    int priority;              /*!< Dialplan: Current extension priority */
00415    char macrocontext[AST_MAX_CONTEXT];    /*!< Macro: Current non-macro context. See app_macro.c */
00416    char macroexten[AST_MAX_EXTENSION];    /*!< Macro: Current non-macro extension. See app_macro.c */
00417    int macropriority;            /*!< Macro: Current non-macro priority. See app_macro.c */
00418    char dialcontext[AST_MAX_CONTEXT];              /*!< Dial: Extension context that we were called from */
00419 
00420    struct ast_pbx *pbx;          /*!< PBX private structure for this channel */
00421    int amaflags;              /*!< Set BEFORE PBX is started to determine AMA flags */
00422    struct ast_cdr *cdr;          /*!< Call Detail Record */
00423    enum ast_channel_adsicpe adsicpe;      /*!< Whether or not ADSI is detected on CPE */
00424 
00425    struct tone_zone *zone;          /*!< Tone zone as set in indications.conf or
00426                         in the CHANNEL dialplan function */
00427 
00428    struct ast_channel_monitor *monitor;      /*!< Channel monitoring */
00429 
00430    unsigned long insmpl;            /*!< Track the read/written samples for monitor use */
00431    unsigned long outsmpl;           /*!< Track the read/written samples for monitor use */
00432 
00433    unsigned int fin;          /*!< Frames in counters. The high bit is a debug mask, so
00434                       * the counter is only in the remaining bits */
00435    unsigned int fout;            /*!< Frames out counters. The high bit is a debug mask, so
00436                       * the counter is only in the remaining bits */
00437    int hangupcause;           /*!< Why is the channel hanged up. See causes.h */
00438    struct varshead varshead;        /*!< A linked list for channel variables 
00439                         (see \ref AstChanVar ) */
00440    ast_group_t callgroup;           /*!< Call group for call pickups */
00441    ast_group_t pickupgroup;         /*!< Pickup group - which calls groups can be picked up? */
00442    unsigned int flags;           /*!< channel flags of AST_FLAG_ type */
00443    unsigned short transfercapability;     /*!< ISDN Transfer Capbility - AST_FLAG_DIGITAL is not enough */
00444    AST_LIST_HEAD_NOLOCK(, ast_frame) readq;
00445    int alertpipe[2];
00446 
00447    int nativeformats;            /*!< Kinds of data this channel can natively handle */
00448    int readformat;               /*!< Requested read format */
00449    int writeformat;           /*!< Requested write format */
00450    struct ast_trans_pvt *writetrans;      /*!< Write translation path */
00451    struct ast_trans_pvt *readtrans;    /*!< Read translation path */
00452    int rawreadformat;            /*!< Raw read format */
00453    int rawwriteformat;           /*!< Raw write format */
00454 
00455    struct ast_audiohook_list *audiohooks;
00456    void *unused; /*! This pointer should stay for Asterisk 1.4.  It just keeps the struct size the same
00457           *  for the sake of ABI compatability. */
00458 
00459    AST_LIST_ENTRY(ast_channel) chan_list;    /*!< For easy linking */
00460    
00461    struct ast_jb jb;          /*!< The jitterbuffer state  */
00462 
00463    char emulate_dtmf_digit;         /*!< Digit being emulated */
00464    unsigned int emulate_dtmf_duration; /*!< Number of ms left to emulate DTMF for */
00465    struct timeval dtmf_tv;       /*!< The time that an in process digit began, or the last digit ended */
00466 
00467    int visible_indication;                         /*!< Indication currently playing on the channel */
00468 
00469    /*! \brief Data stores on the channel */
00470    AST_LIST_HEAD_NOLOCK(datastores, ast_datastore) datastores;
00471 };
00472 
00473 /*! \brief ast_channel_tech Properties */
00474 enum {
00475    /*! \brief Channels have this property if they can accept input with jitter; 
00476     *         i.e. most VoIP channels */
00477    AST_CHAN_TP_WANTSJITTER = (1 << 0),
00478    /*! \brief Channels have this property if they can create jitter; 
00479     *         i.e. most VoIP channels */
00480    AST_CHAN_TP_CREATESJITTER = (1 << 1),
00481 };
00482 
00483 /*! \brief ast_channel flags */
00484 enum {
00485    /*! Queue incoming dtmf, to be released when this flag is turned off */
00486    AST_FLAG_DEFER_DTMF =    (1 << 1),
00487    /*! write should be interrupt generator */
00488    AST_FLAG_WRITE_INT =     (1 << 2),
00489    /*! a thread is blocking on this channel */
00490    AST_FLAG_BLOCKING =      (1 << 3),
00491    /*! This is a zombie channel */
00492    AST_FLAG_ZOMBIE =        (1 << 4),
00493    /*! There is an exception pending */
00494    AST_FLAG_EXCEPTION =     (1 << 5),
00495    /*! Listening to moh XXX anthm promises me this will disappear XXX */
00496    AST_FLAG_MOH =           (1 << 6),
00497    /*! This channel is spying on another channel */
00498    AST_FLAG_SPYING =        (1 << 7),
00499    /*! This channel is in a native bridge */
00500    AST_FLAG_NBRIDGE =       (1 << 8),
00501    /*! the channel is in an auto-incrementing dialplan processor,
00502     *  so when ->priority is set, it will get incremented before
00503     *  finding the next priority to run */
00504    AST_FLAG_IN_AUTOLOOP =   (1 << 9),
00505    /*! This is an outgoing call */
00506    AST_FLAG_OUTGOING =      (1 << 10),
00507    /*! This channel is being whispered on */
00508    AST_FLAG_WHISPER =       (1 << 11),
00509    /*! A DTMF_BEGIN frame has been read from this channel, but not yet an END */
00510    AST_FLAG_IN_DTMF =       (1 << 12),
00511    /*! A DTMF_END was received when not IN_DTMF, so the length of the digit is 
00512     *  currently being emulated */
00513    AST_FLAG_EMULATE_DTMF =  (1 << 13),
00514    /*! This is set to tell the channel not to generate DTMF begin frames, and
00515     *  to instead only generate END frames. */
00516    AST_FLAG_END_DTMF_ONLY = (1 << 14),
00517    /*! This flag indicates that on a masquerade, an active stream should not
00518     *  be carried over */
00519    AST_FLAG_MASQ_NOSTREAM = (1 << 15),
00520 };
00521 
00522 /*! \brief ast_bridge_config flags */
00523 enum {
00524    AST_FEATURE_PLAY_WARNING = (1 << 0),
00525    AST_FEATURE_REDIRECT =     (1 << 1),
00526    AST_FEATURE_DISCONNECT =   (1 << 2),
00527    AST_FEATURE_ATXFER =       (1 << 3),
00528    AST_FEATURE_AUTOMON =      (1 << 4),
00529    AST_FEATURE_PARKCALL =     (1 << 5),
00530 };
00531 
00532 /*! \brief bridge configuration */
00533 struct ast_bridge_config {
00534    struct ast_flags features_caller;
00535    struct ast_flags features_callee;
00536    struct timeval start_time;
00537    long feature_timer;
00538    long timelimit;
00539    long play_warning;
00540    long warning_freq;
00541    const char *warning_sound;
00542    const char *end_sound;
00543    const char *start_sound;
00544    int firstpass;
00545    unsigned int flags;
00546 };
00547 
00548 struct chanmon;
00549 
00550 #define LOAD_OH(oh) {   \
00551    oh.context = context; \
00552    oh.exten = exten; \
00553    oh.priority = priority; \
00554    oh.cid_num = cid_num; \
00555    oh.cid_name = cid_name; \
00556    oh.account = account; \
00557    oh.vars = vars; \
00558    oh.parent_channel = NULL; \
00559 } 
00560 
00561 struct outgoing_helper {
00562    const char *context;
00563    const char *exten;
00564    int priority;
00565    const char *cid_num;
00566    const char *cid_name;
00567    const char *account;
00568    struct ast_variable *vars;
00569    struct ast_channel *parent_channel;
00570 };
00571 
00572 enum {
00573    AST_CDR_TRANSFER =   (1 << 0),
00574    AST_CDR_FORWARD =    (1 << 1),
00575    AST_CDR_CALLWAIT =   (1 << 2),
00576    AST_CDR_CONFERENCE = (1 << 3),
00577 };
00578 
00579 enum {
00580    /*! Soft hangup by device */
00581    AST_SOFTHANGUP_DEV =       (1 << 0),
00582    /*! Soft hangup for async goto */
00583    AST_SOFTHANGUP_ASYNCGOTO = (1 << 1),
00584    AST_SOFTHANGUP_SHUTDOWN =  (1 << 2),
00585    AST_SOFTHANGUP_TIMEOUT =   (1 << 3),
00586    AST_SOFTHANGUP_APPUNLOAD = (1 << 4),
00587    AST_SOFTHANGUP_EXPLICIT =  (1 << 5),
00588    AST_SOFTHANGUP_UNBRIDGE =  (1 << 6),
00589 };
00590 
00591 
00592 /*! \brief Channel reload reasons for manager events at load or reload of configuration */
00593 enum channelreloadreason {
00594    CHANNEL_MODULE_LOAD,
00595    CHANNEL_MODULE_RELOAD,
00596    CHANNEL_CLI_RELOAD,
00597    CHANNEL_MANAGER_RELOAD,
00598 };
00599 
00600 /*! \brief Create a channel datastore structure */
00601 struct ast_datastore *ast_channel_datastore_alloc(const struct ast_datastore_info *info, char *uid);
00602 
00603 /*! \brief Free a channel datastore structure */
00604 int ast_channel_datastore_free(struct ast_datastore *datastore);
00605 
00606 /*! \brief Inherit datastores from a parent to a child. */
00607 int ast_channel_datastore_inherit(struct ast_channel *from, struct ast_channel *to);
00608 
00609 /*! \brief Add a datastore to a channel */
00610 int ast_channel_datastore_add(struct ast_channel *chan, struct ast_datastore *datastore);
00611 
00612 /*! \brief Remove a datastore from a channel */
00613 int ast_channel_datastore_remove(struct ast_channel *chan, struct ast_datastore *datastore);
00614 
00615 /*! \brief Find a datastore on a channel */
00616 struct ast_datastore *ast_channel_datastore_find(struct ast_channel *chan, const struct ast_datastore_info *info, char *uid);
00617 
00618 /*! \brief Change the state of a channel */
00619 int ast_setstate(struct ast_channel *chan, enum ast_channel_state);
00620 
00621 /*! \brief Create a channel structure 
00622     \return Returns NULL on failure to allocate.
00623    \note New channels are 
00624    by default set to the "default" context and
00625    extension "s"
00626  */
00627 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, ...);
00628 
00629 /*! \brief Queue an outgoing frame */
00630 int ast_queue_frame(struct ast_channel *chan, struct ast_frame *f);
00631 
00632 /*! \brief Queue a hangup frame */
00633 int ast_queue_hangup(struct ast_channel *chan);
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   \return zero on success, non-zero on failure
00640 */
00641 int ast_queue_control(struct ast_channel *chan, enum ast_control_frame_type control);
00642 
00643 /*!
00644   \brief Queue a control frame with payload
00645   \param chan channel to queue frame onto
00646   \param control type of control frame
00647   \param data pointer to payload data to be included in frame
00648   \param datalen number of bytes of payload data
00649   \return zero on success, non-zero on failure
00650 
00651   The supplied payload data is copied into the frame, so the caller's copy
00652   is not modified nor freed, and the resulting frame will retain a copy of
00653   the data even if the caller frees their local copy.
00654 
00655   \note This method should be treated as a 'network transport'; in other
00656   words, your frames may be transferred across an IAX2 channel to another
00657   system, which may be a different endianness than yours. Because of this,
00658   you should ensure that either your frames will never be expected to work
00659   across systems, or that you always put your payload data into 'network byte
00660   order' before calling this function.
00661 */
00662 int ast_queue_control_data(struct ast_channel *chan, enum ast_control_frame_type control,
00663             const void *data, size_t datalen);
00664 
00665 /*! \brief Change channel name */
00666 void ast_change_name(struct ast_channel *chan, char *newname);
00667 
00668 /*! \brief Free a channel structure */
00669 void  ast_channel_free(struct ast_channel *);
00670 
00671 /*! \brief Requests a channel 
00672  * \param type type of channel to request
00673  * \param format requested channel format (codec)
00674  * \param data data to pass to the channel requester
00675  * \param status status
00676  * Request a channel of a given type, with data as optional information used 
00677  * by the low level module
00678  * \return Returns an ast_channel on success, NULL on failure.
00679  */
00680 struct ast_channel *ast_request(const char *type, int format, void *data, int *status);
00681 
00682 
00683 /*! \brief call ast_request with format/type of parent channel
00684  */
00685 static inline struct ast_channel *ast_request_inherit(struct ast_channel *chan, const char *type, void *data, int *status)
00686 {
00687    return ast_request(S_OR(type, chan->tech->type), chan->nativeformats, data, status);
00688 }
00689 
00690 /*!
00691  * \brief Request a channel of a given type, with data as optional information used 
00692  * by the low level module and attempt to place a call on it
00693  * \param type type of channel to request
00694  * \param format requested channel format
00695  * \param data data to pass to the channel requester
00696  * \param timeout maximum amount of time to wait for an answer
00697  * \param reason why unsuccessful (if unsuceessful)
00698  * \param cidnum Caller-ID Number
00699  * \param cidname Caller-ID Name
00700  * \return Returns an ast_channel on success or no answer, NULL on failure.  Check the value of chan->_state
00701  * to know if the call was answered or not.
00702  */
00703 struct ast_channel *ast_request_and_dial(const char *type, int format, void *data, int timeout, int *reason, const char *cidnum, const char *cidname);
00704 
00705 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);
00706 
00707 /*!\brief Register a channel technology (a new channel driver)
00708  * Called by a channel module to register the kind of channels it supports.
00709  * \param tech Structure defining channel technology or "type"
00710  * \return Returns 0 on success, -1 on failure.
00711  */
00712 int ast_channel_register(const struct ast_channel_tech *tech);
00713 
00714 /*! \brief Unregister a channel technology 
00715  * \param tech Structure defining channel technology or "type" that was previously registered
00716  * \return No return value.
00717  */
00718 void ast_channel_unregister(const struct ast_channel_tech *tech);
00719 
00720 /*! \brief Get a channel technology structure by name
00721  * \param name name of technology to find
00722  * \return a pointer to the structure, or NULL if no matching technology found
00723  */
00724 const struct ast_channel_tech *ast_get_channel_tech(const char *name);
00725 
00726 /*! \brief Hang up a channel  
00727  * \note This function performs a hard hangup on a channel.  Unlike the soft-hangup, this function
00728  * performs all stream stopping, etc, on the channel that needs to end.
00729  * chan is no longer valid after this call.
00730  * \param chan channel to hang up
00731  * \return Returns 0 on success, -1 on failure.
00732  */
00733 int ast_hangup(struct ast_channel *chan);
00734 
00735 /*! \brief Softly hangup up a channel 
00736  * \param chan channel to be soft-hung-up
00737  * Call the protocol layer, but don't destroy the channel structure (use this if you are trying to
00738  * safely hangup a channel managed by another thread.
00739  * \param cause   Ast hangupcause for hangup
00740  * \return Returns 0 regardless
00741  */
00742 int ast_softhangup(struct ast_channel *chan, int cause);
00743 
00744 /*! \brief Softly hangup up a channel (no channel lock) 
00745  * \param chan channel to be soft-hung-up
00746  * \param cause   Ast hangupcause for hangup (see cause.h) */
00747 int ast_softhangup_nolock(struct ast_channel *chan, int cause);
00748 
00749 /*! \brief Check to see if a channel is needing hang up 
00750  * \param chan channel on which to check for hang up
00751  * This function determines if the channel is being requested to be hung up.
00752  * \return Returns 0 if not, or 1 if hang up is requested (including time-out).
00753  */
00754 int ast_check_hangup(struct ast_channel *chan);
00755 
00756 /*! \brief Compare a offset with the settings of when to hang a channel up 
00757  * \param chan channel on which to check for hang up
00758  * \param offset offset in seconds from current time
00759  * \return 1, 0, or -1
00760  * This function compares a offset from current time with the absolute time 
00761  * out on a channel (when to hang up). If the absolute time out on a channel
00762  * is earlier than current time plus the offset, it returns 1, if the two
00763  * time values are equal, it return 0, otherwise, it retturn -1.
00764  */
00765 int ast_channel_cmpwhentohangup(struct ast_channel *chan, time_t offset);
00766 
00767 /*! \brief Set when to hang a channel up 
00768  * \param chan channel on which to check for hang up
00769  * \param offset offset in seconds from current time of when to hang up
00770  * This function sets the absolute time out on a channel (when to hang up).
00771  */
00772 void ast_channel_setwhentohangup(struct ast_channel *chan, time_t offset);
00773 
00774 /*! \brief Answer a ringing call 
00775  * \param chan channel to answer
00776  * This function answers a channel and handles all necessary call
00777  * setup functions.
00778  * \return Returns 0 on success, -1 on failure
00779  */
00780 int ast_answer(struct ast_channel *chan);
00781 
00782 /*! \brief Make a call 
00783  * \param chan which channel to make the call on
00784  * \param addr destination of the call
00785  * \param timeout time to wait on for connect
00786  * Place a call, take no longer than timeout ms. 
00787    \return Returns -1 on failure, 0 on not enough time 
00788    (does not automatically stop ringing), and  
00789    the number of seconds the connect took otherwise.
00790    */
00791 int ast_call(struct ast_channel *chan, char *addr, int timeout);
00792 
00793 /*! \brief Indicates condition of channel 
00794  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
00795  * \param chan channel to change the indication
00796  * \param condition which condition to indicate on the channel
00797  * \return Returns 0 on success, -1 on failure
00798  */
00799 int ast_indicate(struct ast_channel *chan, int condition);
00800 
00801 /*! \brief Indicates condition of channel, with payload
00802  * \note Indicate a condition such as AST_CONTROL_HOLD with payload being music on hold class
00803  * \param chan channel to change the indication
00804  * \param condition which condition to indicate on the channel
00805  * \param data pointer to payload data
00806  * \param datalen size of payload data
00807  * \return Returns 0 on success, -1 on failure
00808  */
00809 int ast_indicate_data(struct ast_channel *chan, int condition, const void *data, size_t datalen);
00810 
00811 /* Misc stuff ------------------------------------------------ */
00812 
00813 /*! \brief Wait for input on a channel 
00814  * \param chan channel to wait on
00815  * \param ms length of time to wait on the channel
00816  * Wait for input on a channel for a given # of milliseconds (<0 for indefinite). 
00817   \return Returns < 0 on  failure, 0 if nothing ever arrived, and the # of ms remaining otherwise */
00818 int ast_waitfor(struct ast_channel *chan, int ms);
00819 
00820 /*! \brief Wait for a specied amount of time, looking for hangups 
00821  * \param chan channel to wait for
00822  * \param ms length of time in milliseconds to sleep
00823  * Waits for a specified amount of time, servicing the channel as required.
00824  * \return returns -1 on hangup, otherwise 0.
00825  */
00826 int ast_safe_sleep(struct ast_channel *chan, int ms);
00827 
00828 /*! \brief Wait for a specied amount of time, looking for hangups and a condition argument 
00829  * \param chan channel to wait for
00830  * \param ms length of time in milliseconds to sleep
00831  * \param cond a function pointer for testing continue condition
00832  * \param data argument to be passed to the condition test function
00833  * \return returns -1 on hangup, otherwise 0.
00834  * Waits for a specified amount of time, servicing the channel as required. If cond
00835  * returns 0, this function returns.
00836  */
00837 int ast_safe_sleep_conditional(struct ast_channel *chan, int ms, int (*cond)(void*), void *data );
00838 
00839 /*! \brief Waits for activity on a group of channels 
00840  * \param chan an array of pointers to channels
00841  * \param n number of channels that are to be waited upon
00842  * \param fds an array of fds to wait upon
00843  * \param nfds the number of fds to wait upon
00844  * \param exception exception flag
00845  * \param outfd fd that had activity on it
00846  * \param ms how long the wait was
00847  * Big momma function here.  Wait for activity on any of the n channels, or any of the nfds
00848    file descriptors.
00849    \return Returns the channel with activity, or NULL on error or if an FD
00850    came first.  If the FD came first, it will be returned in outfd, otherwise, outfd
00851    will be -1 */
00852 struct ast_channel *ast_waitfor_nandfds(struct ast_channel **chan, int n, int *fds, int nfds, int *exception, int *outfd, int *ms);
00853 
00854 /*! \brief Waits for input on a group of channels
00855    Wait for input on an array of channels for a given # of milliseconds. 
00856    \return Return channel with activity, or NULL if none has activity.  
00857    \param chan an array of pointers to channels
00858    \param n number of channels that are to be waited upon
00859    \param ms time "ms" is modified in-place, if applicable */
00860 struct ast_channel *ast_waitfor_n(struct ast_channel **chan, int n, int *ms);
00861 
00862 /*! \brief Waits for input on an fd
00863    This version works on fd's only.  Be careful with it. */
00864 int ast_waitfor_n_fd(int *fds, int n, int *ms, int *exception);
00865 
00866 
00867 /*! \brief Reads a frame
00868  * \param chan channel to read a frame from
00869  * \return Returns a frame, or NULL on error.  If it returns NULL, you
00870    best just stop reading frames and assume the channel has been
00871    disconnected. */
00872 struct ast_frame *ast_read(struct ast_channel *chan);
00873 
00874 /*! \brief Reads a frame, returning AST_FRAME_NULL frame if audio. 
00875    \param chan channel to read a frame from
00876    \return  Returns a frame, or NULL on error.  If it returns NULL, you
00877       best just stop reading frames and assume the channel has been
00878       disconnected.  
00879    \note Audio is replaced with AST_FRAME_NULL to avoid 
00880    transcode when the resulting audio is not necessary. */
00881 struct ast_frame *ast_read_noaudio(struct ast_channel *chan);
00882 
00883 /*! \brief Write a frame to a channel 
00884  * This function writes the given frame to the indicated channel.
00885  * \param chan destination channel of the frame
00886  * \param frame frame that will be written
00887  * \return It returns 0 on success, -1 on failure.
00888  */
00889 int ast_write(struct ast_channel *chan, struct ast_frame *frame);
00890 
00891 /*! \brief Write video frame to a channel 
00892  * This function writes the given frame to the indicated channel.
00893  * \param chan destination channel of the frame
00894  * \param frame frame that will be written
00895  * \return It returns 1 on success, 0 if not implemented, and -1 on failure.
00896  */
00897 int ast_write_video(struct ast_channel *chan, struct ast_frame *frame);
00898 
00899 /*! \brief Send empty audio to prime a channel driver */
00900 int ast_prod(struct ast_channel *chan);
00901 
00902 /*! \brief Sets read format on channel chan
00903  * Set read format for channel to whichever component of "format" is best. 
00904  * \param chan channel to change
00905  * \param format format to change to
00906  * \return Returns 0 on success, -1 on failure
00907  */
00908 int ast_set_read_format(struct ast_channel *chan, int format);
00909 
00910 /*! \brief Gets read format from channel chan 
00911  * \param chan channel to get info
00912  * Get read format for channel
00913  * Returns read format
00914  */
00915 static inline int ast_get_read_format(struct ast_channel *chan)
00916 {
00917     return chan->readformat;
00918 }
00919 
00920 /*! Gets write format from channel chan */
00921 /*! 
00922  * \param chan channel to get info
00923  * Get write format for channel
00924  * Returns write format
00925  */
00926 static inline int ast_get_write_format(struct ast_channel *chan)
00927 {
00928     return chan->writeformat;
00929 }
00930 
00931 
00932 /*! \brief Sets write format on channel chan
00933  * Set write format for channel to whichever compoent of "format" is best. 
00934  * \param chan channel to change
00935  * \param format new format for writing
00936  * \return Returns 0 on success, -1 on failure
00937  */
00938 int ast_set_write_format(struct ast_channel *chan, int format);
00939 
00940 /*! \brief Sends text to a channel 
00941  * Write text to a display on a channel
00942  * \param chan channel to act upon
00943  * \param text string of text to send on the channel
00944  * \return Returns 0 on success, -1 on failure
00945  */
00946 int ast_sendtext(struct ast_channel *chan, const char *text);
00947 
00948 /*! \brief Receives a text character from a channel
00949  * \param chan channel to act upon
00950  * \param timeout timeout in milliseconds (0 for infinite wait)
00951  * Read a char of text from a channel
00952  * Returns 0 on success, -1 on failure
00953  */
00954 int ast_recvchar(struct ast_channel *chan, int timeout);
00955 
00956 /*! \brief Send a DTMF digit to a channel
00957  * Send a DTMF digit to a channel.
00958  * \param chan channel to act upon
00959  * \param digit the DTMF digit to send, encoded in ASCII
00960  * \return Returns 0 on success, -1 on failure
00961  */
00962 int ast_senddigit(struct ast_channel *chan, char digit);
00963 
00964 /*! \brief Send a DTMF digit to a channel
00965  * Send a DTMF digit to a channel.
00966  * \param chan channel to act upon
00967  * \param digit the DTMF digit to send, encoded in ASCII
00968  * \return Returns 0 on success, -1 on failure
00969  */
00970 int ast_senddigit_begin(struct ast_channel *chan, char digit);
00971 
00972 /*! \brief Send a DTMF digit to a channel
00973 
00974  * Send a DTMF digit to a channel.
00975  * \param chan channel to act upon
00976  * \param digit the DTMF digit to send, encoded in ASCII
00977  * \return Returns 0 on success, -1 on failure
00978  */
00979 int ast_senddigit_end(struct ast_channel *chan, char digit, unsigned int duration);
00980 
00981 /*! \brief Receives a text string from a channel
00982  * Read a string of text from a channel
00983  * \param chan channel to act upon
00984  * \param timeout timeout in milliseconds (0 for infinite wait)
00985  * \return the received text, or NULL to signify failure.
00986  */
00987 char *ast_recvtext(struct ast_channel *chan, int timeout);
00988 
00989 /*! \brief Browse channels in use
00990  * Browse the channels currently in use 
00991  * \param prev where you want to start in the channel list
00992  * \return Returns the next channel in the list, NULL on end.
00993  *    If it returns a channel, that channel *has been locked*!
00994  */
00995 struct ast_channel *ast_channel_walk_locked(const struct ast_channel *prev);
00996 
00997 /*! \brief Get channel by name (locks channel) */
00998 struct ast_channel *ast_get_channel_by_name_locked(const char *chan);
00999 
01000 /*! \brief Get channel by name prefix (locks channel) */
01001 struct ast_channel *ast_get_channel_by_name_prefix_locked(const char *name, const int namelen);
01002 
01003 /*! \brief Get channel by name prefix (locks channel) */
01004 struct ast_channel *ast_walk_channel_by_name_prefix_locked(const struct ast_channel *chan, const char *name, const int namelen);
01005 
01006 /*! \brief Get channel by exten (and optionally context) and lock it */
01007 struct ast_channel *ast_get_channel_by_exten_locked(const char *exten, const char *context);
01008 
01009 /*! \brief Get next channel by exten (and optionally context) and lock it */
01010 struct ast_channel *ast_walk_channel_by_exten_locked(const struct ast_channel *chan, const char *exten,
01011                        const char *context);
01012 
01013 /*! ! \brief Waits for a digit
01014  * \param c channel to wait for a digit on
01015  * \param ms how many milliseconds to wait
01016  * \return Returns <0 on error, 0 on no entry, and the digit on success. */
01017 int ast_waitfordigit(struct ast_channel *c, int ms);
01018 
01019 /*! \brief Wait for a digit
01020  Same as ast_waitfordigit() with audio fd for outputting read audio and ctrlfd to monitor for reading. 
01021  * \param c channel to wait for a digit on
01022  * \param ms how many milliseconds to wait
01023  * \param audiofd audio file descriptor to write to if audio frames are received
01024  * \param ctrlfd control file descriptor to monitor for reading
01025  * \return Returns 1 if ctrlfd becomes available */
01026 int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int ctrlfd);
01027 
01028 /*! Reads multiple digits 
01029  * \param c channel to read from
01030  * \param s string to read in to.  Must be at least the size of your length
01031  * \param len how many digits to read (maximum)
01032  * \param timeout how long to timeout between digits
01033  * \param rtimeout timeout to wait on the first digit
01034  * \param enders digits to end the string
01035  * Read in a digit string "s", max length "len", maximum timeout between 
01036    digits "timeout" (-1 for none), terminated by anything in "enders".  Give them rtimeout
01037    for the first digit.  Returns 0 on normal return, or 1 on a timeout.  In the case of
01038    a timeout, any digits that were read before the timeout will still be available in s.  
01039    RETURNS 2 in full version when ctrlfd is available, NOT 1*/
01040 int ast_readstring(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders);
01041 int ast_readstring_full(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders, int audiofd, int ctrlfd);
01042 
01043 /*! \brief Report DTMF on channel 0 */
01044 #define AST_BRIDGE_DTMF_CHANNEL_0      (1 << 0)    
01045 /*! \brief Report DTMF on channel 1 */
01046 #define AST_BRIDGE_DTMF_CHANNEL_1      (1 << 1)    
01047 /*! \brief Return all voice frames on channel 0 */
01048 #define AST_BRIDGE_REC_CHANNEL_0    (1 << 2)    
01049 /*! \brief Return all voice frames on channel 1 */
01050 #define AST_BRIDGE_REC_CHANNEL_1    (1 << 3)    
01051 /*! \brief Ignore all signal frames except NULL */
01052 #define AST_BRIDGE_IGNORE_SIGS         (1 << 4)    
01053 
01054 
01055 /*! \brief Makes two channel formats compatible 
01056  * \param c0 first channel to make compatible
01057  * \param c1 other channel to make compatible
01058  * Set two channels to compatible formats -- call before ast_channel_bridge in general .  
01059  * \return Returns 0 on success and -1 if it could not be done */
01060 int ast_channel_make_compatible(struct ast_channel *c0, struct ast_channel *c1);
01061 
01062 /*! Bridge two channels together 
01063  * \param c0 first channel to bridge
01064  * \param c1 second channel to bridge
01065  * \param config config for the channels
01066  * \param fo destination frame(?)
01067  * \param rc destination channel(?)
01068  * Bridge two channels (c0 and c1) together.  If an important frame occurs, we return that frame in
01069    *rf (remember, it could be NULL) and which channel (0 or 1) in rc */
01070 /* int ast_channel_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc); */
01071 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);
01072 
01073 /*! \brief Weird function made for call transfers
01074  * \param original channel to make a copy of
01075  * \param clone copy of the original channel
01076  * This is a very strange and freaky function used primarily for transfer.  Suppose that
01077    "original" and "clone" are two channels in random situations.  This function takes
01078    the guts out of "clone" and puts them into the "original" channel, then alerts the
01079    channel driver of the change, asking it to fixup any private information (like the
01080    p->owner pointer) that is affected by the change.  The physical layer of the original
01081    channel is hung up.  */
01082 int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clone);
01083 
01084 /*! Gives the string form of a given cause code */
01085 /*! 
01086  * \param state cause to get the description of
01087  * Give a name to a cause code
01088  * Returns the text form of the binary cause code given
01089  */
01090 const char *ast_cause2str(int state) attribute_pure;
01091 
01092 /*! Convert the string form of a cause code to a number */
01093 /*! 
01094  * \param name string form of the cause
01095  * Returns the cause code
01096  */
01097 int ast_str2cause(const char *name) attribute_pure;
01098 
01099 /*! Gives the string form of a given channel state */
01100 /*! 
01101  * \param ast_channel_state state to get the name of
01102  * Give a name to a state 
01103  * Returns the text form of the binary state given
01104  */
01105 char *ast_state2str(enum ast_channel_state);
01106 
01107 /*! Gives the string form of a given transfer capability */
01108 /*!
01109  * \param transfercapability transfercapabilty to get the name of
01110  * Give a name to a transfercapbility
01111  * See above
01112  * Returns the text form of the binary transfer capbility
01113  */
01114 char *ast_transfercapability2str(int transfercapability) attribute_const;
01115 
01116 /* Options: Some low-level drivers may implement "options" allowing fine tuning of the
01117    low level channel.  See frame.h for options.  Note that many channel drivers may support
01118    none or a subset of those features, and you should not count on this if you want your
01119    asterisk application to be portable.  They're mainly useful for tweaking performance */
01120 
01121 /*! Sets an option on a channel */
01122 /*! 
01123  * \param channel channel to set options on
01124  * \param option option to change
01125  * \param data data specific to option
01126  * \param datalen length of the data
01127  * \param block blocking or not
01128  * Set an option on a channel (see frame.h), optionally blocking awaiting the reply 
01129  * Returns 0 on success and -1 on failure
01130  */
01131 int ast_channel_setoption(struct ast_channel *channel, int option, void *data, int datalen, int block);
01132 
01133 /*! Pick the best codec  */
01134 /* Choose the best codec...  Uhhh...   Yah. */
01135 int ast_best_codec(int fmts);
01136 
01137 /*! 
01138  * \brief Pick the best codec from channel nativeformats
01139  * \param channel channel, from that nativeformats used
01140  */
01141 static inline int ast_channel_best_codec(struct ast_channel *channel)
01142 {
01143 #ifndef BUG_4825 
01144    return ast_best_codec(channel->nativeformats);
01145 #else 
01146    return ast_best_codec(channel->nativeformats.audio_bits);
01147 #endif   
01148 }
01149 /*! \brief Get the names of a set of formats
01150  * \param buf a buffer for the output string
01151  * \param size size of buf (bytes)
01152  * \param channel the channel
01153  * Prints a list of readable codec names corresponding to "format".
01154  * ex: for format=AST_FORMAT_GSM|AST_FORMAT_SPEEX|AST_FORMAT_ILBC it will return "0x602 (GSM|SPEEX|ILBC)"
01155  * \return The return value is buf.
01156  */
01157 inline static char * ast_channel_getformatname_multiple(char *buf, size_t size, struct ast_channel *chan)
01158 {
01159    return ast_getformatname_multiple(buf, size, chan->nativeformats);
01160 }
01161 
01162 
01163 static inline const char * ast_channel_getformatname(struct ast_channel *chan)
01164 {
01165 #ifndef BUG_4825 
01166    return chan ? ast_getformatname(chan->nativeformats) : "undefined";
01167 #else 
01168    return chan ? ast_getformatname(chan->nativeformats.audio_bits) : "undefined";
01169 #endif   
01170 }
01171 
01172 static inline void ast_channel_formats_reset(struct ast_channel *channel)
01173 {
01174    int r, w;
01175    r = ast_get_read_format(channel);
01176    w = ast_get_write_format(channel);
01177 
01178    if (option_debug)
01179       ast_log(LOG_DEBUG, "Resetting read to %d and write to %d on channel %s\n", r, w, channel->name);
01180    if (r)
01181       ast_set_read_format(channel, r);
01182    if (w)
01183       ast_set_write_format(channel, w);
01184 }
01185 
01186 /*!
01187  * \brief Set best format, identical to read/write
01188  * \param channel channel, from that nativeformats used and formats set
01189  */
01190 static inline void ast_set_best_format(struct ast_channel *channel)
01191 {
01192     int format = ast_channel_best_codec(channel);
01193     ast_set_read_format(channel, format);
01194     ast_set_write_format(channel, format);
01195 }
01196 
01197 /*! Checks the value of an option */
01198 /*! 
01199  * Query the value of an option, optionally blocking until a reply is received
01200  * Works similarly to setoption except only reads the options.
01201  */
01202 struct ast_frame *ast_channel_queryoption(struct ast_channel *channel, int option, void *data, int *datalen, int block);
01203 
01204 /*! Checks for HTML support on a channel */
01205 /*! Returns 0 if channel does not support HTML or non-zero if it does */
01206 int ast_channel_supports_html(struct ast_channel *channel);
01207 
01208 /*! Sends HTML on given channel */
01209 /*! Send HTML or URL on link.  Returns 0 on success or -1 on failure */
01210 int ast_channel_sendhtml(struct ast_channel *channel, int subclass, const char *data, int datalen);
01211 
01212 /*! Sends a URL on a given link */
01213 /*! Send URL on link.  Returns 0 on success or -1 on failure */
01214 int ast_channel_sendurl(struct ast_channel *channel, const char *url);
01215 
01216 /*! Defers DTMF */
01217 /*! Defer DTMF so that you only read things like hangups and audio.  Returns
01218    non-zero if channel was already DTMF-deferred or 0 if channel is just now
01219    being DTMF-deferred */
01220 int ast_channel_defer_dtmf(struct ast_channel *chan);
01221 
01222 /*! Undeos a defer */
01223 /*! Undo defer.  ast_read will return any dtmf characters that were queued */
01224 void ast_channel_undefer_dtmf(struct ast_channel *chan);
01225 
01226 /*! Initiate system shutdown -- prevents new channels from being allocated.
01227     If "hangup" is non-zero, all existing channels will receive soft
01228      hangups */
01229 void ast_begin_shutdown(int hangup);
01230 
01231 /*! Cancels an existing shutdown and returns to normal operation */
01232 void ast_cancel_shutdown(void);
01233 
01234 /*! Returns number of active/allocated channels */
01235 int ast_active_channels(void);
01236 
01237 /*! Returns non-zero if Asterisk is being shut down */
01238 int ast_shutting_down(void);
01239 
01240 /*! Activate a given generator */
01241 int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params);
01242 
01243 /*! Deactive an active generator */
01244 void ast_deactivate_generator(struct ast_channel *chan);
01245 
01246 /*!
01247  * \note The channel does not need to be locked before calling this function.
01248  */
01249 void ast_set_callerid(struct ast_channel *chan, const char *cidnum, const char *cidname, const char *ani);
01250 
01251 
01252 /*! return a mallocd string with the result of sprintf of the fmt and following args */
01253 char *ast_safe_string_alloc(const char *fmt, ...);
01254 
01255 
01256 
01257 /*! Start a tone going */
01258 int ast_tonepair_start(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01259 /*! Stop a tone from playing */
01260 void ast_tonepair_stop(struct ast_channel *chan);
01261 /*! Play a tone pair for a given amount of time */
01262 int ast_tonepair(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01263 
01264 /*!
01265  * \brief Automatically service a channel for us... 
01266  *
01267  * \retval 0 success
01268  * \retval -1 failure, or the channel is already being autoserviced
01269  */
01270 int ast_autoservice_start(struct ast_channel *chan);
01271 
01272 /*! 
01273  * \brief Stop servicing a channel for us...  
01274  *
01275  * \retval 0 success
01276  * \retval -1 error, or the channel has been hungup 
01277  */
01278 int ast_autoservice_stop(struct ast_channel *chan);
01279 
01280 /* If built with zaptel optimizations, force a scheduled expiration on the
01281    timer fd, at which point we call the callback function / data */
01282 int ast_settimeout(struct ast_channel *c, int samples, int (*func)(const void *data), void *data);
01283 
01284 /*!   \brief Transfer a channel (if supported).  Returns -1 on error, 0 if not supported
01285    and 1 if supported and requested 
01286    \param chan current channel
01287    \param dest destination extension for transfer
01288 */
01289 int ast_transfer(struct ast_channel *chan, char *dest);
01290 
01291 /*!   \brief  Start masquerading a channel
01292    XXX This is a seriously wacked out operation.  We're essentially putting the guts of
01293            the clone channel into the original channel.  Start by killing off the original
01294            channel's backend.   I'm not sure we're going to keep this function, because
01295            while the features are nice, the cost is very high in terms of pure nastiness. XXX
01296    \param chan    Channel to masquerade
01297 */
01298 int ast_do_masquerade(struct ast_channel *chan);
01299 
01300 /*!   \brief Find bridged channel 
01301    \param chan Current channel
01302 */
01303 struct ast_channel *ast_bridged_channel(struct ast_channel *chan);
01304 
01305 /*!
01306   \brief Inherits channel variable from parent to child channel
01307   \param parent Parent channel
01308   \param child Child channel
01309 
01310   Scans all channel variables in the parent channel, looking for those
01311   that should be copied into the child channel.
01312   Variables whose names begin with a single '_' are copied into the
01313   child channel with the prefix removed.
01314   Variables whose names begin with '__' are copied into the child
01315   channel with their names unchanged.
01316 */
01317 void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child);
01318 
01319 /*!
01320   \brief adds a list of channel variables to a channel
01321   \param chan the channel
01322   \param vars a linked list of variables
01323 
01324   Variable names can be for a regular channel variable or a dialplan function
01325   that has the ability to be written to.
01326 */
01327 void ast_set_variables(struct ast_channel *chan, struct ast_variable *vars);
01328 
01329 /*!
01330   \brief An opaque 'object' structure use by silence generators on channels.
01331  */
01332 struct ast_silence_generator;
01333 
01334 /*!
01335   \brief Starts a silence generator on the given channel.
01336   \param chan The channel to generate silence on
01337   \return An ast_silence_generator pointer, or NULL if an error occurs
01338 
01339   This function will cause SLINEAR silence to be generated on the supplied
01340   channel until it is disabled; if the channel cannot be put into SLINEAR
01341   mode then the function will fail.
01342 
01343   The pointer returned by this function must be preserved and passed to
01344   ast_channel_stop_silence_generator when you wish to stop the silence
01345   generation.
01346  */
01347 struct ast_silence_generator *ast_channel_start_silence_generator(struct ast_channel *chan);
01348 
01349 /*!
01350   \brief Stops a previously-started silence generator on the given channel.
01351   \param chan The channel to operate on
01352   \param state The ast_silence_generator pointer return by a previous call to
01353   ast_channel_start_silence_generator.
01354   \return nothing
01355 
01356   This function will stop the operating silence generator and return the channel
01357   to its previous write format.
01358  */
01359 void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state);
01360 
01361 /*!
01362   \brief Check if the channel can run in internal timing mode.
01363   \param chan The channel to check
01364   \return boolean
01365 
01366   This function will return 1 if internal timing is enabled and the timing
01367   device is available.
01368  */
01369 int ast_internal_timing_enabled(struct ast_channel *chan);
01370 
01371 /* Misc. functions below */
01372 
01373 /*! \brief if fd is a valid descriptor, set *pfd with the descriptor
01374  * \return Return 1 (not -1!) if added, 0 otherwise (so we can add the
01375  * return value to the index into the array)
01376  */
01377 static inline int ast_add_fd(struct pollfd *pfd, int fd)
01378 {
01379    pfd->fd = fd;
01380    pfd->events = POLLIN | POLLPRI;
01381    return fd >= 0;
01382 }
01383 
01384 /*! \brief Helper function for migrating select to poll */
01385 static inline int ast_fdisset(struct pollfd *pfds, int fd, int max, int *start)
01386 {
01387    int x;
01388    int dummy=0;
01389 
01390    if (fd < 0)
01391       return 0;
01392    if (!start)
01393       start = &dummy;
01394    for (x = *start; x<max; x++)
01395       if (pfds[x].fd == fd) {
01396          if (x == *start)
01397             (*start)++;
01398          return pfds[x].revents;
01399       }
01400    return 0;
01401 }
01402 
01403 #ifdef SOLARIS
01404 static inline void timersub(struct timeval *tvend, struct timeval *tvstart, struct timeval *tvdiff)
01405 {
01406    tvdiff->tv_sec = tvend->tv_sec - tvstart->tv_sec;
01407    tvdiff->tv_usec = tvend->tv_usec - tvstart->tv_usec;
01408    if (tvdiff->tv_usec < 0) {
01409       tvdiff->tv_sec --;
01410       tvdiff->tv_usec += 1000000;
01411    }
01412 
01413 }
01414 #endif
01415 
01416 /*! \brief Waits for activity on a group of channels 
01417  * \param nfds the maximum number of file descriptors in the sets
01418  * \param rfds file descriptors to check for read availability
01419  * \param wfds file descriptors to check for write availability
01420  * \param efds file descriptors to check for exceptions (OOB data)
01421  * \param tvp timeout while waiting for events
01422  * This is the same as a standard select(), except it guarantees the
01423  * behaviour where the passed struct timeval is updated with how much
01424  * time was not slept while waiting for the specified events
01425  */
01426 static inline int ast_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *tvp)
01427 {
01428 #ifdef __linux__
01429    return select(nfds, rfds, wfds, efds, tvp);
01430 #else
01431    if (tvp) {
01432       struct timeval tv, tvstart, tvend, tvlen;
01433       int res;
01434 
01435       tv = *tvp;
01436       gettimeofday(&tvstart, NULL);
01437       res = select(nfds, rfds, wfds, efds, tvp);
01438       gettimeofday(&tvend, NULL);
01439       timersub(&tvend, &tvstart, &tvlen);
01440       timersub(&tv, &tvlen, tvp);
01441       if (tvp->tv_sec < 0 || (tvp->tv_sec == 0 && tvp->tv_usec < 0)) {
01442          tvp->tv_sec = 0;
01443          tvp->tv_usec = 0;
01444       }
01445       return res;
01446    }
01447    else
01448       return select(nfds, rfds, wfds, efds, NULL);
01449 #endif
01450 }
01451 
01452 #ifdef DO_CRASH
01453 #define CRASH do { fprintf(stderr, "!! Forcing immediate crash a-la abort !!\n"); *((int *)0) = 0; } while(0)
01454 #else
01455 #define CRASH do { } while(0)
01456 #endif
01457 
01458 #define CHECK_BLOCKING(c) do {    \
01459    if (ast_test_flag(c, AST_FLAG_BLOCKING)) {\
01460       if (option_debug) \
01461          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); \
01462       CRASH; \
01463    } else { \
01464       (c)->blocker = pthread_self(); \
01465       (c)->blockproc = __PRETTY_FUNCTION__; \
01466       ast_set_flag(c, AST_FLAG_BLOCKING); \
01467    } } while (0)
01468 
01469 ast_group_t ast_get_group(const char *s);
01470 
01471 /*! \brief print call- and pickup groups into buffer */
01472 char *ast_print_group(char *buf, int buflen, ast_group_t group);
01473 
01474 /*! \brief Convert enum channelreloadreason to text string for manager event
01475    \param reason  Enum channelreloadreason - reason for reload (manager, cli, start etc)
01476 */
01477 const char *channelreloadreason2txt(enum channelreloadreason reason);
01478 
01479 /*! \brief return an ast_variable list of channeltypes */
01480 struct ast_variable *ast_channeltype_list(void);
01481 
01482 /*!
01483   \brief Begin 'whispering' onto a channel
01484   \param chan The channel to whisper onto
01485   \return 0 for success, non-zero for failure
01486 
01487   This function will add a whisper buffer onto a channel and set a flag
01488   causing writes to the channel to reduce the volume level of the written
01489   audio samples, and then to mix in audio from the whisper buffer if it
01490   is available.
01491 
01492   \note Note: This function performs no locking; you must hold the channel's lock before
01493   calling this function.
01494  */
01495 int ast_channel_whisper_start(struct ast_channel *chan);
01496 
01497 /*!
01498   \brief Feed an audio frame into the whisper buffer on a channel
01499   \param chan The channel to whisper onto
01500   \param f The frame to to whisper onto chan
01501   \return 0 for success, non-zero for failure
01502  */
01503 int ast_channel_whisper_feed(struct ast_channel *chan, struct ast_frame *f);
01504 
01505 /*!
01506   \brief Stop 'whispering' onto a channel
01507   \param chan The channel to whisper onto
01508   \return 0 for success, non-zero for failure
01509 
01510   Note: This function performs no locking; you must hold the channel's lock before
01511   calling this function.
01512  */
01513 void ast_channel_whisper_stop(struct ast_channel *chan);
01514 
01515 
01516 
01517 /*!
01518   \brief return an english explanation of the code returned thru __ast_request_and_dial's 'outstate' argument
01519   \param reason  The integer argument, usually taken from AST_CONTROL_ macros
01520   \return char pointer explaining the code
01521  */
01522 char *ast_channel_reason2str(int reason);
01523 
01524 
01525 #if defined(__cplusplus) || defined(c_plusplus)
01526 }
01527 #endif
01528 
01529 #endif /* _ASTERISK_CHANNEL_H */

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