Wed Oct 28 11:45:36 2009

Asterisk developer's documentation


channel.h

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2006, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  * \brief General Asterisk PBX channel definitions.
00021  * \par See also:
00022  *  \arg \ref Def_Channel
00023  *  \arg \ref channel_drivers
00024  */
00025 
00026 /*! \page Def_Channel Asterisk Channels
00027    \par What is a Channel?
00028    A phone call through Asterisk consists of an incoming
00029    connection and an outbound connection. Each call comes
00030    in through a channel driver that supports one technology,
00031    like SIP, DAHDI, IAX2 etc. 
00032    \par
00033    Each channel driver, technology, has it's own private
00034    channel or dialog structure, that is technology-dependent.
00035    Each private structure is "owned" by a generic Asterisk
00036    channel structure, defined in channel.h and handled by
00037    channel.c .
00038    \par Call scenario
00039    This happens when an incoming call arrives to Asterisk
00040    -# Call arrives on a channel driver interface
00041    -# Channel driver creates a PBX channel and starts a 
00042       pbx thread on the channel
00043    -# The dial plan is executed
00044    -# At this point at least two things can happen:
00045       -# The call is answered by Asterisk and 
00046          Asterisk plays a media stream or reads media
00047       -# The dial plan forces Asterisk to create an outbound 
00048          call somewhere with the dial (see \ref app_dial.c)
00049          application
00050    .
00051 
00052    \par Bridging channels
00053    If Asterisk dials out this happens:
00054    -# Dial creates an outbound PBX channel and asks one of the
00055       channel drivers to create a call
00056    -# When the call is answered, Asterisk bridges the media streams
00057       so the caller on the first channel can speak with the callee
00058       on the second, outbound channel
00059    -# In some cases where we have the same technology on both
00060       channels and compatible codecs, a native bridge is used.
00061       In a native bridge, the channel driver handles forwarding
00062       of incoming audio to the outbound stream internally, without
00063       sending audio frames through the PBX.
00064    -# In SIP, theres an "external native bridge" where Asterisk
00065       redirects the endpoint, so audio flows directly between the
00066       caller's phone and the callee's phone. Signalling stays in
00067       Asterisk in order to be able to provide a proper CDR record
00068       for the call.
00069 
00070    
00071    \par Masquerading channels
00072    In some cases, a channel can masquerade itself into another
00073    channel. This happens frequently in call transfers, where 
00074    a new channel takes over a channel that is already involved
00075    in a call. The new channel sneaks in and takes over the bridge
00076    and the old channel, now a zombie, is hung up.
00077    
00078    \par Reference
00079    \arg channel.c - generic functions
00080    \arg channel.h - declarations of functions, flags and structures
00081    \arg translate.h - Transcoding support functions
00082    \arg \ref channel_drivers - Implemented channel drivers
00083    \arg \ref Def_Frame Asterisk Multimedia Frames
00084    \arg \ref Def_Bridge
00085 
00086 */
00087 /*! \page Def_Bridge Asterisk Channel Bridges
00088 
00089    In Asterisk, there's several media bridges. 
00090 
00091    The Core bridge handles two channels (a "phone call") and bridge
00092    them together.
00093    
00094    The conference bridge (meetme) handles several channels simultaneously
00095    with the support of an external timer (DAHDI timer). This is used
00096    not only by the Conference application (meetme) but also by the
00097    page application and the SLA system introduced in 1.4.
00098    The conference bridge does not handle video.
00099 
00100    When two channels of the same type connect, the channel driver
00101    or the media subsystem used by the channel driver (i.e. RTP)
00102    can create a native bridge without sending media through the
00103    core.
00104 
00105    Native briding can be disabled by a number of reasons,
00106    like DTMF being needed by the core or codecs being incompatible
00107    so a transcoding module is needed.
00108 
00109 References:
00110    \li \see ast_channel_early_bridge()
00111    \li \see ast_channel_bridge()
00112    \li \see app_meetme.c
00113    \li \ref AstRTPbridge
00114    \li \see ast_rtp_bridge() 
00115    \li \ref Def_Channel
00116 */
00117 
00118 /*! \page AstFileDesc File descriptors 
00119    Asterisk File descriptors are connected to each channel (see \ref Def_Channel)
00120    in the \ref ast_channel structure.
00121 */
00122 
00123 #ifndef _ASTERISK_CHANNEL_H
00124 #define _ASTERISK_CHANNEL_H
00125 
00126 #include "asterisk/abstract_jb.h"
00127 
00128 #include "asterisk/poll-compat.h"
00129 
00130 #if defined(__cplusplus) || defined(c_plusplus)
00131 extern "C" {
00132 #endif
00133 
00134 #define AST_MAX_EXTENSION  80 /*!< Max length of an extension */
00135 #define AST_MAX_CONTEXT    80 /*!< Max length of a context */
00136 #define AST_CHANNEL_NAME   80 /*!< Max length of an ast_channel name */
00137 #define MAX_LANGUAGE    20 /*!< Max length of the language setting */
00138 #define MAX_MUSICCLASS     80 /*!< Max length of the music class setting */
00139 
00140 #include "asterisk/frame.h"
00141 #include "asterisk/sched.h"
00142 #include "asterisk/chanvars.h"
00143 #include "asterisk/config.h"
00144 #include "asterisk/lock.h"
00145 #include "asterisk/cdr.h"
00146 #include "asterisk/utils.h"
00147 #include "asterisk/linkedlists.h"
00148 #include "asterisk/stringfields.h"
00149 
00150 #define DATASTORE_INHERIT_FOREVER   INT_MAX
00151 
00152 #define AST_MAX_FDS     10
00153 /*
00154  * We have AST_MAX_FDS file descriptors in a channel.
00155  * Some of them have a fixed use:
00156  */
00157 #define AST_ALERT_FD (AST_MAX_FDS-1)      /*!< used for alertpipe */
00158 #define AST_TIMING_FD   (AST_MAX_FDS-2)      /*!< used for timingfd */
00159 #define AST_AGENT_FD (AST_MAX_FDS-3)      /*!< used by agents for pass through */
00160 #define AST_GENERATOR_FD   (AST_MAX_FDS-4)   /*!< used by generator */
00161 
00162 enum ast_bridge_result {
00163    AST_BRIDGE_COMPLETE = 0,
00164    AST_BRIDGE_FAILED = -1,
00165    AST_BRIDGE_FAILED_NOWARN = -2,
00166    AST_BRIDGE_RETRY = -3,
00167 };
00168 
00169 typedef unsigned long long ast_group_t;
00170 
00171 /*! \todo Add an explanation of an Asterisk generator 
00172 */
00173 struct ast_generator {
00174    void *(*alloc)(struct ast_channel *chan, void *params);
00175    void (*release)(struct ast_channel *chan, void *data);
00176    /*! This function gets called with the channel unlocked, but is called in
00177     *  the context of the channel thread so we know the channel is not going
00178     *  to disappear.  This callback is responsible for locking the channel as
00179     *  necessary. */
00180    int (*generate)(struct ast_channel *chan, void *data, int len, int samples);
00181    /*! This gets called when DTMF_END frames are read from the channel */
00182    void (*digit)(struct ast_channel *chan, char digit);
00183 };
00184 
00185 /*! \brief Structure for a data store type */
00186 struct ast_datastore_info {
00187    const char *type;    /*!< Type of data store */
00188    void *(*duplicate)(void *data);  /*!< Duplicate item data (used for inheritance) */
00189    void (*destroy)(void *data);  /*!< Destroy function */
00190    /*!
00191     * \brief Fix up channel references
00192     *
00193     * \arg data The datastore data
00194     * \arg old_chan The old channel owning the datastore
00195     * \arg new_chan The new channel owning the datastore
00196     *
00197     * This is exactly like the fixup callback of the channel technology interface.
00198     * It allows a datastore to fix any pointers it saved to the owning channel
00199     * in case that the owning channel has changed.  Generally, this would happen
00200     * when the datastore is set to be inherited, and a masquerade occurs.
00201     *
00202     * \return nothing.
00203     */
00204    void (*chan_fixup)(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan);
00205 };
00206 
00207 /*! \brief Structure for a channel data store */
00208 struct ast_datastore {
00209    const char *uid;     /*!< Unique data store identifier */
00210    void *data;    /*!< Contained data */
00211    const struct ast_datastore_info *info; /*!< Data store type information */
00212    unsigned int inheritance;  /*!< Number of levels this item will continue to be inherited */
00213    AST_LIST_ENTRY(ast_datastore) entry; /*!< Used for easy linking */
00214 };
00215 
00216 /*! \brief Structure for all kinds of caller ID identifications.
00217  * \note All string fields here are malloc'ed, so they need to be
00218  * freed when the structure is deleted.
00219  * Also, NULL and "" must be considered equivalent.
00220  * 
00221  * SIP and IAX2 has utf8 encoded Unicode caller ID names.
00222  * In some cases, we also have an alternative (RPID) E.164 number that can be used
00223  * as caller ID on numeric E.164 phone networks (DAHDI or SIP/IAX2 to pstn gateway).
00224  *
00225  * \todo Implement settings for transliteration between UTF8 caller ID names in
00226  *       to Ascii Caller ID's (DAHDI). Ísten ┼sklund might be transliterated into
00227  *  Osten Asklund or Oesten Aasklund depending upon language and person...
00228  *  We need automatic routines for incoming calls and static settings for
00229  *     our own accounts.
00230  */
00231 struct ast_callerid {
00232    char *cid_dnid;      /*!< Malloc'd Dialed Number Identifier */
00233    char *cid_num;    /*!< Malloc'd Caller Number */
00234    char *cid_name;      /*!< Malloc'd Caller Name (ASCII) */
00235    char *cid_ani;    /*!< Malloc'd ANI */
00236    char *cid_rdnis;  /*!< Malloc'd RDNIS */
00237    int cid_pres;     /*!< Callerid presentation/screening */
00238    int cid_ani2;     /*!< Callerid ANI 2 (Info digits) */
00239    int cid_ton;      /*!< Callerid Type of Number */
00240    int cid_tns;      /*!< Callerid Transit Network Select */
00241 };
00242 
00243 /*! \brief 
00244    Structure to describe a channel "technology", ie a channel driver 
00245    See for examples:
00246    \arg chan_iax2.c - The Inter-Asterisk exchange protocol
00247    \arg chan_sip.c - The SIP channel driver
00248    \arg chan_dahdi.c - PSTN connectivity (TDM, PRI, T1/E1, FXO, FXS)
00249 
00250    If you develop your own channel driver, this is where you
00251    tell the PBX at registration of your driver what properties
00252    this driver supports and where different callbacks are 
00253    implemented.
00254 */
00255 struct ast_channel_tech {
00256    const char * const type;
00257    const char * const description;
00258 
00259    int capabilities;    /*!< Bitmap of formats this channel can handle */
00260 
00261    int properties;         /*!< Technology Properties */
00262 
00263    /*! \brief Requester - to set up call data structures (pvt's) */
00264    struct ast_channel *(* const requester)(const char *type, int format, void *data, int *cause);
00265 
00266    int (* const devicestate)(void *data); /*!< Devicestate call back */
00267 
00268    /*! 
00269     * \brief Start sending a literal DTMF digit 
00270     *
00271     * \note The channel is not locked when this function gets called. 
00272     */
00273    int (* const send_digit_begin)(struct ast_channel *chan, char digit);
00274 
00275    /*! 
00276     * \brief Stop sending a literal DTMF digit 
00277     *
00278     * \note The channel is not locked when this function gets called. 
00279     */
00280    int (* const send_digit_end)(struct ast_channel *chan, char digit, unsigned int duration);
00281 
00282    /*! \brief Call a given phone number (address, etc), but don't
00283       take longer than timeout seconds to do so.  */
00284    int (* const call)(struct ast_channel *chan, char *addr, int timeout);
00285 
00286    /*! \brief Hangup (and possibly destroy) the channel */
00287    int (* const hangup)(struct ast_channel *chan);
00288 
00289    /*! \brief Answer the channel */
00290    int (* const answer)(struct ast_channel *chan);
00291 
00292    /*! \brief Read a frame, in standard format (see frame.h) */
00293    struct ast_frame * (* const read)(struct ast_channel *chan);
00294 
00295    /*! \brief Write a frame, in standard format (see frame.h) */
00296    int (* const write)(struct ast_channel *chan, struct ast_frame *frame);
00297 
00298    /*! \brief Display or transmit text */
00299    int (* const send_text)(struct ast_channel *chan, const char *text);
00300 
00301    /*! \brief Display or send an image */
00302    int (* const send_image)(struct ast_channel *chan, struct ast_frame *frame);
00303 
00304    /*! \brief Send HTML data */
00305    int (* const send_html)(struct ast_channel *chan, int subclass, const char *data, int len);
00306 
00307    /*! \brief Handle an exception, reading a frame */
00308    struct ast_frame * (* const exception)(struct ast_channel *chan);
00309 
00310    /*! \brief Bridge two channels of the same type together */
00311    enum ast_bridge_result (* const bridge)(struct ast_channel *c0, struct ast_channel *c1, int flags,
00312                   struct ast_frame **fo, struct ast_channel **rc, int timeoutms);
00313 
00314    /*! \brief Bridge two channels of the same type together (early) */
00315    enum ast_bridge_result (* const early_bridge)(struct ast_channel *c0, struct ast_channel *c1);
00316 
00317    /*! \brief Indicate a particular condition (e.g. AST_CONTROL_BUSY or AST_CONTROL_RINGING or AST_CONTROL_CONGESTION */
00318    int (* const indicate)(struct ast_channel *c, int condition, const void *data, size_t datalen);
00319 
00320    /*! \brief Fix up a channel:  If a channel is consumed, this is called.  Basically update any ->owner links */
00321    int (* const fixup)(struct ast_channel *oldchan, struct ast_channel *newchan);
00322 
00323    /*! \brief Set a given option */
00324    int (* const setoption)(struct ast_channel *chan, int option, void *data, int datalen);
00325 
00326    /*! \brief Query a given option */
00327    int (* const queryoption)(struct ast_channel *chan, int option, void *data, int *datalen);
00328 
00329    /*! \brief Blind transfer other side (see app_transfer.c and ast_transfer() */
00330    int (* const transfer)(struct ast_channel *chan, const char *newdest);
00331 
00332    /*! \brief Write a frame, in standard format */
00333    int (* const write_video)(struct ast_channel *chan, struct ast_frame *frame);
00334 
00335    /*! \brief Write a text frame, in standard format */
00336    int (* const write_text)(struct ast_channel *chan, struct ast_frame *frame);
00337 
00338    /*! \brief Find bridged channel */
00339    struct ast_channel *(* const bridged_channel)(struct ast_channel *chan, struct ast_channel *bridge);
00340 
00341    /*! \brief Provide additional read items for CHANNEL() dialplan function */
00342    int (* func_channel_read)(struct ast_channel *chan, const char *function, char *data, char *buf, size_t len);
00343 
00344    /*! \brief Provide additional write items for CHANNEL() dialplan function */
00345    int (* func_channel_write)(struct ast_channel *chan, const char *function, char *data, const char *value);
00346 
00347    /*! \brief Retrieve base channel (agent and local) */
00348    struct ast_channel* (* get_base_channel)(struct ast_channel *chan);
00349    
00350    /*! \brief Set base channel (agent and local) */
00351    int (* set_base_channel)(struct ast_channel *chan, struct ast_channel *base);
00352 
00353    /*! \brief Get the unique identifier for the PVT, i.e. SIP call-ID for SIP */
00354    const char * (* get_pvt_uniqueid)(struct ast_channel *chan);
00355 };
00356 
00357 struct ast_epoll_data;
00358 
00359 /*!
00360  * The high bit of the frame count is used as a debug marker, so
00361  * increments of the counters must be done with care.
00362  * Please use c->fin = FRAMECOUNT_INC(c->fin) and the same for c->fout.
00363  */
00364 #define  DEBUGCHAN_FLAG  0x80000000
00365 
00366 /* XXX not ideal to evaluate x twice... */
00367 #define  FRAMECOUNT_INC(x) ( ((x) & DEBUGCHAN_FLAG) | (((x)+1) & ~DEBUGCHAN_FLAG) )
00368 
00369 /*!
00370  * The current value of the debug flags is stored in the two
00371  * variables global_fin and global_fout (declared in main/channel.c)
00372  */
00373 extern unsigned long global_fin, global_fout;
00374 
00375 enum ast_channel_adsicpe {
00376    AST_ADSI_UNKNOWN,
00377    AST_ADSI_AVAILABLE,
00378    AST_ADSI_UNAVAILABLE,
00379    AST_ADSI_OFFHOOKONLY,
00380 };
00381 
00382 /*! 
00383  * \brief ast_channel states
00384  *
00385  * \note Bits 0-15 of state are reserved for the state (up/down) of the line
00386  *       Bits 16-32 of state are reserved for flags
00387  */
00388 enum ast_channel_state {
00389    AST_STATE_DOWN,         /*!< Channel is down and available */
00390    AST_STATE_RESERVED,     /*!< Channel is down, but reserved */
00391    AST_STATE_OFFHOOK,      /*!< Channel is off hook */
00392    AST_STATE_DIALING,      /*!< Digits (or equivalent) have been dialed */
00393    AST_STATE_RING,         /*!< Line is ringing */
00394    AST_STATE_RINGING,      /*!< Remote end is ringing */
00395    AST_STATE_UP,        /*!< Line is up */
00396    AST_STATE_BUSY,         /*!< Line is busy */
00397    AST_STATE_DIALING_OFFHOOK, /*!< Digits (or equivalent) have been dialed while offhook */
00398    AST_STATE_PRERING,      /*!< Channel has detected an incoming call and is waiting for ring */
00399 
00400    AST_STATE_MUTE = (1 << 16),   /*!< Do not transmit voice data */
00401 };
00402 
00403 /*!
00404  * \brief Possible T38 states on channels
00405  */
00406 enum ast_t38_state {
00407    T38_STATE_UNAVAILABLE,  /*!< T38 is unavailable on this channel or disabled by configuration */
00408    T38_STATE_UNKNOWN,   /*!< The channel supports T38 but the current status is unknown */
00409    T38_STATE_NEGOTIATING,  /*!< T38 is being negotiated */
00410    T38_STATE_REJECTED,  /*!< Remote side has rejected our offer */
00411    T38_STATE_NEGOTIATED,   /*!< T38 established */
00412 };
00413 
00414 /*! \brief Main Channel structure associated with a channel. 
00415  * This is the side of it mostly used by the pbx and call management.
00416  *
00417  * \note XXX It is important to remember to increment .cleancount each time
00418  *       this structure is changed. XXX
00419  */
00420 
00421 struct ast_channel {
00422    const struct ast_channel_tech *tech;      /*!< Technology (point to channel driver) */
00423 
00424    void *tech_pvt;               /*!< Private data used by the technology driver */
00425 
00426    AST_DECLARE_STRING_FIELDS(
00427       AST_STRING_FIELD(name);       /*!< ASCII unique channel name */
00428       AST_STRING_FIELD(language);      /*!< Language requested for voice prompts */
00429       AST_STRING_FIELD(musicclass);    /*!< Default music class */
00430       AST_STRING_FIELD(accountcode);      /*!< Account code for billing */
00431       AST_STRING_FIELD(call_forward);     /*!< Where to forward to if asked to dial on this interface */
00432       AST_STRING_FIELD(uniqueid);      /*!< Unique Channel Identifier */
00433    );
00434    
00435    int fds[AST_MAX_FDS];            /*!< File descriptors for channel -- Drivers will poll on
00436                         these file descriptors, so at least one must be non -1.
00437                          See \arg \ref AstFileDesc */
00438 
00439    void *music_state;            /*!< Music State*/
00440    void *generatordata;          /*!< Current generator data if there is any */
00441    struct ast_generator *generator;    /*!< Current active data generator */
00442 
00443    struct ast_channel *_bridge;        /*!< Who are we bridged to, if we're bridged.
00444                         Who is proxying for us, if we are proxied (i.e. chan_agent).
00445                         Do not access directly, use ast_bridged_channel(chan) */
00446 
00447    struct ast_channel *masq;        /*!< Channel that will masquerade as us */
00448    struct ast_channel *masqr;       /*!< Who we are masquerading as */
00449    int cdrflags;              /*!< Call Detail Record Flags */
00450 
00451    int _softhangup;           /*!< Whether or not we have been hung up...  Do not set this value
00452                            directly, use ast_softhangup() */
00453    time_t   whentohangup;           /*!< Non-zero, set to actual time when channel is to be hung up */
00454    pthread_t blocker;            /*!< If anyone is blocking, this is them */
00455    ast_mutex_t lock_dont_use;       /*!< Lock a channel for some operations. See ast_channel_lock() */
00456    const char *blockproc;           /*!< Procedure causing blocking */
00457 
00458    const char *appl;          /*!< Current application */
00459    const char *data;          /*!< Data passed to current application */
00460    int fdno;               /*!< Which fd had an event detected on */
00461    struct sched_context *sched;        /*!< Schedule context */
00462    int streamid;              /*!< For streaming playback, the schedule ID */
00463    struct ast_filestream *stream;         /*!< Stream itself. */
00464    int vstreamid;             /*!< For streaming video playback, the schedule ID */
00465    struct ast_filestream *vstream;        /*!< Video Stream itself. */
00466    int oldwriteformat;           /*!< Original writer format */
00467    
00468    int timingfd;              /*!< Timing fd */
00469    int (*timingfunc)(const void *data);
00470    void *timingdata;
00471 
00472    enum ast_channel_state _state;         /*!< State of line -- Don't write directly, use ast_setstate() */
00473    int rings;              /*!< Number of rings so far */
00474    struct ast_callerid cid;         /*!< Caller ID, name, presentation etc */
00475    char unused_old_dtmfq[AST_MAX_EXTENSION];       /*!< (deprecated, use the readq) Any/all queued DTMF characters */
00476    struct ast_frame dtmff;          /*!< DTMF frame */
00477 
00478    char context[AST_MAX_CONTEXT];         /*!< Dialplan: Current extension context */
00479    char exten[AST_MAX_EXTENSION];         /*!< Dialplan: Current extension number */
00480    int priority;              /*!< Dialplan: Current extension priority */
00481    char macrocontext[AST_MAX_CONTEXT];    /*!< Macro: Current non-macro context. See app_macro.c */
00482    char macroexten[AST_MAX_EXTENSION];    /*!< Macro: Current non-macro extension. See app_macro.c */
00483    int macropriority;            /*!< Macro: Current non-macro priority. See app_macro.c */
00484    char dialcontext[AST_MAX_CONTEXT];              /*!< Dial: Extension context that we were called from */
00485 
00486    struct ast_pbx *pbx;          /*!< PBX private structure for this channel */
00487    int amaflags;              /*!< Set BEFORE PBX is started to determine AMA flags */
00488    struct ast_cdr *cdr;          /*!< Call Detail Record */
00489    enum ast_channel_adsicpe adsicpe;      /*!< Whether or not ADSI is detected on CPE */
00490 
00491    struct tone_zone *zone;       /*!< Tone zone as set in indications.conf or
00492                         in the CHANNEL dialplan function */
00493 
00494    struct ast_channel_monitor *monitor;      /*!< Channel monitoring */
00495 
00496    unsigned long insmpl;            /*!< Track the read/written samples for monitor use */
00497    unsigned long outsmpl;           /*!< Track the read/written samples for monitor use */
00498 
00499    unsigned int fin;          /*!< Frames in counters. The high bit is a debug mask, so
00500                         the counter is only in the remaining bits */
00501    unsigned int fout;            /*!< Frames out counters. The high bit is a debug mask, so
00502                         the counter is only in the remaining bits */
00503    int hangupcause;           /*!< Why is the channel hanged up. See causes.h */
00504    struct varshead varshead;        /*!< A linked list for channel variables. See \ref AstChanVar */
00505    ast_group_t callgroup;           /*!< Call group for call pickups */
00506    ast_group_t pickupgroup;         /*!< Pickup group - which calls groups can be picked up? */
00507    unsigned int flags;           /*!< channel flags of AST_FLAG_ type */
00508    unsigned short transfercapability;     /*!< ISDN Transfer Capbility - AST_FLAG_DIGITAL is not enough */
00509    AST_LIST_HEAD_NOLOCK(, ast_frame) readq;
00510    int alertpipe[2];
00511 
00512    int nativeformats;            /*!< Kinds of data this channel can natively handle */
00513    int readformat;               /*!< Requested read format */
00514    int writeformat;           /*!< Requested write format */
00515    struct ast_trans_pvt *writetrans;      /*!< Write translation path */
00516    struct ast_trans_pvt *readtrans;    /*!< Read translation path */
00517    int rawreadformat;            /*!< Raw read format */
00518    int rawwriteformat;           /*!< Raw write format */
00519 
00520    struct ast_audiohook_list *audiohooks;
00521 
00522    AST_LIST_ENTRY(ast_channel) chan_list;    /*!< For easy linking */
00523    
00524    struct ast_jb jb;          /*!< The jitterbuffer state  */
00525 
00526    char emulate_dtmf_digit;         /*!< Digit being emulated */
00527    unsigned int emulate_dtmf_duration;    /*!< Number of ms left to emulate DTMF for */
00528    struct timeval dtmf_tv;          /*!< The time that an in process digit began, or the last digit ended */
00529 
00530    AST_LIST_HEAD_NOLOCK(datastores, ast_datastore) datastores; /*!< Data stores on the channel */
00531 
00532 #ifdef HAVE_EPOLL
00533    int epfd;
00534    struct ast_epoll_data *epfd_data[AST_MAX_FDS];
00535 #endif
00536    int visible_indication;                         /*!< Indication currently playing on the channel */
00537 };
00538 
00539 /*! \brief ast_channel_tech Properties */
00540 enum {
00541    /*! \brief Channels have this property if they can accept input with jitter; 
00542     *         i.e. most VoIP channels */
00543    AST_CHAN_TP_WANTSJITTER = (1 << 0),
00544    /*! \brief Channels have this property if they can create jitter; 
00545     *         i.e. most VoIP channels */
00546    AST_CHAN_TP_CREATESJITTER = (1 << 1),
00547 };
00548 
00549 /*! \brief ast_channel flags */
00550 enum {
00551    /*! Queue incoming dtmf, to be released when this flag is turned off */
00552    AST_FLAG_DEFER_DTMF =    (1 << 1),
00553    /*! write should be interrupt generator */
00554    AST_FLAG_WRITE_INT =     (1 << 2),
00555    /*! a thread is blocking on this channel */
00556    AST_FLAG_BLOCKING =      (1 << 3),
00557    /*! This is a zombie channel */
00558    AST_FLAG_ZOMBIE =        (1 << 4),
00559    /*! There is an exception pending */
00560    AST_FLAG_EXCEPTION =     (1 << 5),
00561    /*! Listening to moh XXX anthm promises me this will disappear XXX */
00562    AST_FLAG_MOH =           (1 << 6),
00563    /*! This channel is spying on another channel */
00564    AST_FLAG_SPYING =        (1 << 7),
00565    /*! This channel is in a native bridge */
00566    AST_FLAG_NBRIDGE =       (1 << 8),
00567    /*! the channel is in an auto-incrementing dialplan processor,
00568     *  so when ->priority is set, it will get incremented before
00569     *  finding the next priority to run */
00570    AST_FLAG_IN_AUTOLOOP =   (1 << 9),
00571    /*! This is an outgoing call */
00572    AST_FLAG_OUTGOING =      (1 << 10),
00573    /*! A DTMF_BEGIN frame has been read from this channel, but not yet an END */
00574    AST_FLAG_IN_DTMF =       (1 << 12),
00575    /*! A DTMF_END was received when not IN_DTMF, so the length of the digit is 
00576     *  currently being emulated */
00577    AST_FLAG_EMULATE_DTMF =  (1 << 13),
00578    /*! This is set to tell the channel not to generate DTMF begin frames, and
00579     *  to instead only generate END frames. */
00580    AST_FLAG_END_DTMF_ONLY = (1 << 14),
00581    /*! Flag to show channels that this call is hangup due to the fact that the call
00582        was indeed anwered, but in another channel */
00583    AST_FLAG_ANSWERED_ELSEWHERE = (1 << 15),
00584    /*! This flag indicates that on a masquerade, an active stream should not
00585     *  be carried over */
00586    AST_FLAG_MASQ_NOSTREAM = (1 << 16),
00587    /*! This flag indicates that the hangup exten was run when the bridge terminated,
00588     *  a message aimed at preventing a subsequent hangup exten being run at the pbx_run
00589     *  level */
00590    AST_FLAG_BRIDGE_HANGUP_RUN = (1 << 17),
00591    /*! This flag indicates that the hangup exten should NOT be run when the 
00592     *  bridge terminates, this will allow the hangup in the pbx loop to be run instead.
00593     *  */
00594    AST_FLAG_BRIDGE_HANGUP_DONT = (1 << 18),
00595    /*! This flag indicates whether the channel is in the channel list or not. */
00596    AST_FLAG_IN_CHANNEL_LIST = (1 << 19),
00597 };
00598 
00599 /*! \brief ast_bridge_config flags */
00600 enum {
00601    AST_FEATURE_PLAY_WARNING = (1 << 0),
00602    AST_FEATURE_REDIRECT =     (1 << 1),
00603    AST_FEATURE_DISCONNECT =   (1 << 2),
00604    AST_FEATURE_ATXFER =       (1 << 3),
00605    AST_FEATURE_AUTOMON =      (1 << 4),
00606    AST_FEATURE_PARKCALL =     (1 << 5),
00607    AST_FEATURE_AUTOMIXMON =   (1 << 6),
00608    AST_FEATURE_NO_H_EXTEN =   (1 << 7),
00609    AST_FEATURE_WARNING_ACTIVE = (1 << 8),
00610 };
00611 
00612 /*! \brief bridge configuration */
00613 struct ast_bridge_config {
00614    struct ast_flags features_caller;
00615    struct ast_flags features_callee;
00616    struct timeval start_time;
00617    struct timeval nexteventts;
00618    struct timeval partialfeature_timer;
00619    long feature_timer;
00620    long timelimit;
00621    long play_warning;
00622    long warning_freq;
00623    const char *warning_sound;
00624    const char *end_sound;
00625    const char *start_sound;
00626    int firstpass;
00627    unsigned int flags;
00628    void (* end_bridge_callback)(void *);   /*!< A callback that is called after a bridge attempt */
00629    void *end_bridge_callback_data;         /*!< Data passed to the callback */
00630    /*! If the end_bridge_callback_data refers to a channel which no longer is going to
00631     * exist when the end_bridge_callback is called, then it needs to be fixed up properly
00632     */
00633    void (*end_bridge_callback_data_fixup)(struct ast_bridge_config *bconfig, struct ast_channel *originator, struct ast_channel *terminator);
00634 };
00635 
00636 struct chanmon;
00637 
00638 struct outgoing_helper {
00639    const char *context;
00640    const char *exten;
00641    int priority;
00642    const char *cid_num;
00643    const char *cid_name;
00644    const char *account;
00645    struct ast_variable *vars;
00646    struct ast_channel *parent_channel;
00647 };
00648 
00649 enum {
00650    AST_CDR_TRANSFER =   (1 << 0),
00651    AST_CDR_FORWARD =    (1 << 1),
00652    AST_CDR_CALLWAIT =   (1 << 2),
00653    AST_CDR_CONFERENCE = (1 << 3),
00654 };
00655 
00656 enum {
00657    /*! Soft hangup by device */
00658    AST_SOFTHANGUP_DEV =       (1 << 0),
00659    /*! Soft hangup for async goto */
00660    AST_SOFTHANGUP_ASYNCGOTO = (1 << 1),
00661    AST_SOFTHANGUP_SHUTDOWN =  (1 << 2),
00662    AST_SOFTHANGUP_TIMEOUT =   (1 << 3),
00663    AST_SOFTHANGUP_APPUNLOAD = (1 << 4),
00664    AST_SOFTHANGUP_EXPLICIT =  (1 << 5),
00665    AST_SOFTHANGUP_UNBRIDGE =  (1 << 6),
00666 };
00667 
00668 
00669 /*! \brief Channel reload reasons for manager events at load or reload of configuration */
00670 enum channelreloadreason {
00671    CHANNEL_MODULE_LOAD,
00672    CHANNEL_MODULE_RELOAD,
00673    CHANNEL_CLI_RELOAD,
00674    CHANNEL_MANAGER_RELOAD,
00675 };
00676 
00677 /*! 
00678  * \brief Create a channel datastore structure 
00679  *
00680  * \note None of the datastore API calls lock the ast_channel they are using.
00681  *       So, the channel should be locked before calling the functions that
00682  *       take a channel argument.
00683  */
00684 struct ast_datastore *ast_channel_datastore_alloc(const struct ast_datastore_info *info, const char *uid);
00685 
00686 /*! \brief Free a channel datastore structure */
00687 int ast_channel_datastore_free(struct ast_datastore *datastore);
00688 
00689 /*! \brief Inherit datastores from a parent to a child. */
00690 int ast_channel_datastore_inherit(struct ast_channel *from, struct ast_channel *to);
00691 
00692 /*! 
00693  * \brief Add a datastore to a channel 
00694  *
00695  * \note The channel should be locked before calling this function.
00696  *
00697  * \retval 0 success
00698  * \retval non-zero failure
00699  */
00700 
00701 int ast_channel_datastore_add(struct ast_channel *chan, struct ast_datastore *datastore);
00702 
00703 /*! 
00704  * \brief Remove a datastore from a channel 
00705  *
00706  * \note The channel should be locked before calling this function.
00707  *
00708  * \retval 0 success
00709  * \retval non-zero failure
00710  */
00711 int ast_channel_datastore_remove(struct ast_channel *chan, struct ast_datastore *datastore);
00712 
00713 /*! 
00714  * \brief Find a datastore on a channel 
00715  *
00716  * \note The channel should be locked before calling this function.
00717  *
00718  * \note The datastore returned from this function must not be used if the
00719  *       reference to the channel is released.
00720  */
00721 struct ast_datastore *ast_channel_datastore_find(struct ast_channel *chan, const struct ast_datastore_info *info, const char *uid);
00722 
00723 /*! \brief Change the state of a channel */
00724 int ast_setstate(struct ast_channel *chan, enum ast_channel_state);
00725 
00726 /*! 
00727  * \brief Create a channel structure 
00728  *
00729  * \retval NULL failure
00730  * \retval non-NULL successfully allocated channel
00731  *
00732  * \note By default, new channels are set to the "s" extension
00733  *       and "default" context.
00734  */
00735 struct ast_channel * attribute_malloc __attribute__((format(printf, 12, 13)))
00736    __ast_channel_alloc(int needqueue, int state, const char *cid_num,
00737              const char *cid_name, const char *acctcode,
00738              const char *exten, const char *context,
00739              const int amaflag, const char *file, int line,
00740              const char *function, const char *name_fmt, ...);
00741 
00742 #define ast_channel_alloc(needqueue, state, cid_num, cid_name, acctcode, exten, context, amaflag, ...) \
00743    __ast_channel_alloc(needqueue, state, cid_num, cid_name, acctcode, exten, context, amaflag, \
00744              __FILE__, __LINE__, __FUNCTION__, __VA_ARGS__)
00745 
00746 /*!
00747  * \brief Queue one or more frames to a channel's frame queue
00748  *
00749  * \param chan the channel to queue the frame(s) on
00750  * \param f the frame(s) to queue.  Note that the frame(s) will be duplicated
00751  *        by this function.  It is the responsibility of the caller to handle
00752  *        freeing the memory associated with the frame(s) being passed if
00753  *        necessary.
00754  *
00755  * \retval 0 success
00756  * \retval non-zero failure
00757  */
00758 int ast_queue_frame(struct ast_channel *chan, struct ast_frame *f);
00759 
00760 /*!
00761  * \brief Queue one or more frames to the head of a channel's frame queue
00762  *
00763  * \param chan the channel to queue the frame(s) on
00764  * \param f the frame(s) to queue.  Note that the frame(s) will be duplicated
00765  *        by this function.  It is the responsibility of the caller to handle
00766  *        freeing the memory associated with the frame(s) being passed if
00767  *        necessary.
00768  *
00769  * \retval 0 success
00770  * \retval non-zero failure
00771  */
00772 int ast_queue_frame_head(struct ast_channel *chan, struct ast_frame *f);
00773 
00774 /*! 
00775  * \brief Queue a hangup frame 
00776  *
00777  * \note The channel does not need to be locked before calling this function.
00778  */
00779 int ast_queue_hangup(struct ast_channel *chan);
00780 
00781 /*!
00782  * \brief Queue a control frame with payload
00783  *
00784  * \param chan channel to queue frame onto
00785  * \param control type of control frame
00786  *
00787  * \note The channel does not need to be locked before calling this function.
00788  *
00789  * \retval zero on success
00790  * \retval non-zero on failure
00791  */
00792 int ast_queue_control(struct ast_channel *chan, enum ast_control_frame_type control);
00793 
00794 /*!
00795  * \brief Queue a control frame with payload
00796  *
00797  * \param chan channel to queue frame onto
00798  * \param control type of control frame
00799  * \param data pointer to payload data to be included in frame
00800  * \param datalen number of bytes of payload data
00801  *
00802  * \retval 0 success
00803  * \retval non-zero failure
00804  *
00805  * The supplied payload data is copied into the frame, so the caller's copy
00806  * is not modified nor freed, and the resulting frame will retain a copy of
00807  * the data even if the caller frees their local copy.
00808  *
00809  * \note This method should be treated as a 'network transport'; in other
00810  * words, your frames may be transferred across an IAX2 channel to another
00811  * system, which may be a different endianness than yours. Because of this,
00812  * you should ensure that either your frames will never be expected to work
00813  * across systems, or that you always put your payload data into 'network byte
00814  * order' before calling this function.
00815  *
00816  * \note The channel does not need to be locked before calling this function.
00817  */
00818 int ast_queue_control_data(struct ast_channel *chan, enum ast_control_frame_type control,
00819             const void *data, size_t datalen);
00820 
00821 /*! 
00822  * \brief Change channel name 
00823  *
00824  * \note The channel must be locked before calling this function.
00825  */
00826 void ast_change_name(struct ast_channel *chan, char *newname);
00827 
00828 /*! \brief Free a channel structure */
00829 void  ast_channel_free(struct ast_channel *);
00830 
00831 /*! 
00832  * \brief Requests a channel 
00833  *
00834  * \param type type of channel to request
00835  * \param format requested channel format (codec)
00836  * \param data data to pass to the channel requester
00837  * \param status status
00838  *
00839  * Request a channel of a given type, with data as optional information used 
00840  * by the low level module
00841  *
00842  * \retval NULL failure
00843  * \retval non-NULL channel on success
00844  */
00845 struct ast_channel *ast_request(const char *type, int format, void *data, int *status);
00846 
00847 /*!
00848  * \brief Request a channel of a given type, with data as optional information used 
00849  *        by the low level module and attempt to place a call on it
00850  *
00851  * \param type type of channel to request
00852  * \param format requested channel format
00853  * \param data data to pass to the channel requester
00854  * \param timeout maximum amount of time to wait for an answer
00855  * \param reason why unsuccessful (if unsuccessful)
00856  * \param cid_num Caller-ID Number
00857  * \param cid_name Caller-ID Name (ascii)
00858  *
00859  * \return Returns an ast_channel on success or no answer, NULL on failure.  Check the value of chan->_state
00860  * to know if the call was answered or not.
00861  */
00862 struct ast_channel *ast_request_and_dial(const char *type, int format, void *data,
00863    int timeout, int *reason, const char *cid_num, const char *cid_name);
00864 
00865 /*!
00866  * \brief Request a channel of a given type, with data as optional information used 
00867  * by the low level module and attempt to place a call on it
00868  * \param type type of channel to request
00869  * \param format requested channel format
00870  * \param data data to pass to the channel requester
00871  * \param timeout maximum amount of time to wait for an answer
00872  * \param reason why unsuccessful (if unsuccessful)
00873  * \param cid_num Caller-ID Number
00874  * \param cid_name Caller-ID Name (ascii)
00875  * \param oh Outgoing helper
00876  * \return Returns an ast_channel on success or no answer, NULL on failure.  Check the value of chan->_state
00877  * to know if the call was answered or not.
00878  */
00879 struct ast_channel *__ast_request_and_dial(const char *type, int format, void *data,
00880    int timeout, int *reason, const char *cid_num, const char *cid_name, struct outgoing_helper *oh);
00881 /*!
00882 * \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.
00883 * \param caller in channel that requested orig
00884 * \param orig channel being replaced by the call forward channel
00885 * \param timeout maximum amount of time to wait for setup of new forward channel
00886 * \param format requested channel format
00887 * \param oh outgoing helper used with original channel
00888 * \param outstate reason why unsuccessful (if uncuccessful)
00889 * \return Returns the forwarded call's ast_channel on success or NULL on failure
00890 */
00891 struct ast_channel *ast_call_forward(struct ast_channel *caller, struct ast_channel *orig, int *timeout, int format, struct outgoing_helper *oh, int *outstate);
00892 
00893 /*!\brief Register a channel technology (a new channel driver)
00894  * Called by a channel module to register the kind of channels it supports.
00895  * \param tech Structure defining channel technology or "type"
00896  * \return Returns 0 on success, -1 on failure.
00897  */
00898 int ast_channel_register(const struct ast_channel_tech *tech);
00899 
00900 /*! \brief Unregister a channel technology 
00901  * \param tech Structure defining channel technology or "type" that was previously registered
00902  * \return No return value.
00903  */
00904 void ast_channel_unregister(const struct ast_channel_tech *tech);
00905 
00906 /*! \brief Get a channel technology structure by name
00907  * \param name name of technology to find
00908  * \return a pointer to the structure, or NULL if no matching technology found
00909  */
00910 const struct ast_channel_tech *ast_get_channel_tech(const char *name);
00911 
00912 #ifdef CHANNEL_TRACE
00913 /*! \brief Update the context backtrace if tracing is enabled
00914  * \return Returns 0 on success, -1 on failure
00915  */
00916 int ast_channel_trace_update(struct ast_channel *chan);
00917 
00918 /*! \brief Enable context tracing in the channel
00919  * \return Returns 0 on success, -1 on failure
00920  */
00921 int ast_channel_trace_enable(struct ast_channel *chan);
00922 
00923 /*! \brief Disable context tracing in the channel.
00924  * \note Does not remove current trace entries
00925  * \return Returns 0 on success, -1 on failure
00926  */
00927 int ast_channel_trace_disable(struct ast_channel *chan);
00928 
00929 /*! \brief Whether or not context tracing is enabled
00930  * \return Returns -1 when the trace is enabled. 0 if not.
00931  */
00932 int ast_channel_trace_is_enabled(struct ast_channel *chan);
00933 
00934 /*! \brief Put the channel backtrace in a string
00935  * \return Returns the amount of lines in the backtrace. -1 on error.
00936  */
00937 int ast_channel_trace_serialize(struct ast_channel *chan, struct ast_str **out);
00938 #endif
00939 
00940 /*! \brief Hang up a channel  
00941  * \note This function performs a hard hangup on a channel.  Unlike the soft-hangup, this function
00942  * performs all stream stopping, etc, on the channel that needs to end.
00943  * chan is no longer valid after this call.
00944  * \param chan channel to hang up
00945  * \return Returns 0 on success, -1 on failure.
00946  */
00947 int ast_hangup(struct ast_channel *chan);
00948 
00949 /*! 
00950  * \brief Softly hangup up a channel 
00951  *
00952  * \param chan channel to be soft-hung-up
00953  * \param reason an AST_SOFTHANGUP_* reason code
00954  *
00955  * Call the protocol layer, but don't destroy the channel structure 
00956  * (use this if you are trying to
00957  * safely hangup a channel managed by another thread.
00958  *
00959  * \note The channel passed to this function does not need to be locked.
00960  *
00961  * \return Returns 0 regardless
00962  */
00963 int ast_softhangup(struct ast_channel *chan, int reason);
00964 
00965 /*! \brief Softly hangup up a channel (no channel lock) 
00966  * \param chan channel to be soft-hung-up
00967  * \param reason an AST_SOFTHANGUP_* reason code
00968  */
00969 int ast_softhangup_nolock(struct ast_channel *chan, int reason);
00970 
00971 /*! \brief Check to see if a channel is needing hang up 
00972  * \param chan channel on which to check for hang up
00973  * This function determines if the channel is being requested to be hung up.
00974  * \return Returns 0 if not, or 1 if hang up is requested (including time-out).
00975  */
00976 int ast_check_hangup(struct ast_channel *chan);
00977 
00978 /*! \brief Compare a offset with the settings of when to hang a channel up 
00979  * \param chan channel on which to check for hang up
00980  * \param offset offset in seconds from current time
00981  * \return 1, 0, or -1
00982  * This function compares a offset from current time with the absolute time 
00983  * out on a channel (when to hang up). If the absolute time out on a channel
00984  * is earlier than current time plus the offset, it returns 1, if the two
00985  * time values are equal, it return 0, otherwise, it return -1.
00986  */
00987 int ast_channel_cmpwhentohangup(struct ast_channel *chan, time_t offset);
00988 
00989 /*! \brief Set when to hang a channel up 
00990  *
00991  * \param chan channel on which to check for hang up
00992  * \param offset offset in seconds from current time of when to hang up
00993  *
00994  * This function sets the absolute time out on a channel (when to hang up).
00995  *
00996  * \note This function does not require that the channel is locked before
00997  *       calling it.
00998  *
00999  * \return Nothing
01000  */
01001 void ast_channel_setwhentohangup(struct ast_channel *chan, time_t offset);
01002 
01003 /*! 
01004  * \brief Answer a channel
01005  * 
01006  * \param chan channel to answer
01007  *
01008  * This function answers a channel and handles all necessary call
01009  * setup functions.
01010  *
01011  * \note The channel passed does not need to be locked, but is locked
01012  * by the function when needed.
01013  *
01014  * \note This function will wait up to 500 milliseconds for media to
01015  * arrive on the channel before returning to the caller, so that the
01016  * caller can properly assume the channel is 'ready' for media flow.
01017  *
01018  * \retval 0 on success
01019  * \retval non-zero on failure
01020  */
01021 int ast_answer(struct ast_channel *chan);
01022 
01023 /*!
01024  * \brief Answer a channel
01025  *
01026  * \param chan channel to answer
01027  * \param cdr_answer flag to control whether any associated CDR should be marked as 'answered'
01028  *
01029  * This function answers a channel and handles all necessary call
01030  * setup functions.
01031  *
01032  * \note The channel passed does not need to be locked, but is locked
01033  * by the function when needed.
01034  *
01035  * \note Unlike ast_answer(), this function will not wait for media
01036  * flow to begin. The caller should be careful before sending media
01037  * to the channel before incoming media arrives, as the outgoing
01038  * media may be lost.
01039  *
01040  * \retval 0 on success
01041  * \retval non-zero on failure
01042  */
01043 int ast_raw_answer(struct ast_channel *chan, int cdr_answer);
01044 
01045 /*!
01046  * \brief Answer a channel, with a selectable delay before returning
01047  *
01048  * \param chan channel to answer
01049  * \param delay maximum amount of time to wait for incoming media
01050  * \param cdr_answer flag to control whether any associated CDR should be marked as 'answered'
01051  *
01052  * This function answers a channel and handles all necessary call
01053  * setup functions.
01054  *
01055  * \note The channel passed does not need to be locked, but is locked
01056  * by the function when needed.
01057  *
01058  * \note This function will wait up to 'delay' milliseconds for media to
01059  * arrive on the channel before returning to the caller, so that the
01060  * caller can properly assume the channel is 'ready' for media flow. If
01061  * 'delay' is less than 500, the function will wait up to 500 milliseconds.
01062  *
01063  * \retval 0 on success
01064  * \retval non-zero on failure
01065  */
01066 int __ast_answer(struct ast_channel *chan, unsigned int delay, int cdr_answer);
01067 
01068 /*! \brief Make a call 
01069  * \param chan which channel to make the call on
01070  * \param addr destination of the call
01071  * \param timeout time to wait on for connect
01072  * Place a call, take no longer than timeout ms. 
01073    \return Returns -1 on failure, 0 on not enough time 
01074    (does not automatically stop ringing), and  
01075    the number of seconds the connect took otherwise.
01076    */
01077 int ast_call(struct ast_channel *chan, char *addr, int timeout);
01078 
01079 /*! \brief Indicates condition of channel 
01080  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
01081  * \param chan channel to change the indication
01082  * \param condition which condition to indicate on the channel
01083  * \return Returns 0 on success, -1 on failure
01084  */
01085 int ast_indicate(struct ast_channel *chan, int condition);
01086 
01087 /*! \brief Indicates condition of channel, with payload
01088  * \note Indicate a condition such as AST_CONTROL_HOLD with payload being music on hold class
01089  * \param chan channel to change the indication
01090  * \param condition which condition to indicate on the channel
01091  * \param data pointer to payload data
01092  * \param datalen size of payload data
01093  * \return Returns 0 on success, -1 on failure
01094  */
01095 int ast_indicate_data(struct ast_channel *chan, int condition, const void *data, size_t datalen);
01096 
01097 /* Misc stuff ------------------------------------------------ */
01098 
01099 /*! \brief Wait for input on a channel 
01100  * \param chan channel to wait on
01101  * \param ms length of time to wait on the channel
01102  * Wait for input on a channel for a given # of milliseconds (<0 for indefinite). 
01103   \return Returns < 0 on  failure, 0 if nothing ever arrived, and the # of ms remaining otherwise */
01104 int ast_waitfor(struct ast_channel *chan, int ms);
01105 
01106 /*! \brief Wait for a specified amount of time, looking for hangups 
01107  * \param chan channel to wait for
01108  * \param ms length of time in milliseconds to sleep
01109  * Waits for a specified amount of time, servicing the channel as required.
01110  * \return returns -1 on hangup, otherwise 0.
01111  */
01112 int ast_safe_sleep(struct ast_channel *chan, int ms);
01113 
01114 /*! \brief Wait for a specified amount of time, looking for hangups and a condition argument 
01115  * \param chan channel to wait for
01116  * \param ms length of time in milliseconds to sleep
01117  * \param cond a function pointer for testing continue condition
01118  * \param data argument to be passed to the condition test function
01119  * \return returns -1 on hangup, otherwise 0.
01120  * Waits for a specified amount of time, servicing the channel as required. If cond
01121  * returns 0, this function returns.
01122  */
01123 int ast_safe_sleep_conditional(struct ast_channel *chan, int ms, int (*cond)(void*), void *data );
01124 
01125 /*! \brief Waits for activity on a group of channels 
01126  * \param chan an array of pointers to channels
01127  * \param n number of channels that are to be waited upon
01128  * \param fds an array of fds to wait upon
01129  * \param nfds the number of fds to wait upon
01130  * \param exception exception flag
01131  * \param outfd fd that had activity on it
01132  * \param ms how long the wait was
01133  * Big momma function here.  Wait for activity on any of the n channels, or any of the nfds
01134    file descriptors.
01135    \return Returns the channel with activity, or NULL on error or if an FD
01136    came first.  If the FD came first, it will be returned in outfd, otherwise, outfd
01137    will be -1 */
01138 struct ast_channel *ast_waitfor_nandfds(struct ast_channel **chan, int n,
01139    int *fds, int nfds, int *exception, int *outfd, int *ms);
01140 
01141 /*! \brief Waits for input on a group of channels
01142    Wait for input on an array of channels for a given # of milliseconds. 
01143    \return Return channel with activity, or NULL if none has activity.  
01144    \param chan an array of pointers to channels
01145    \param n number of channels that are to be waited upon
01146    \param ms time "ms" is modified in-place, if applicable */
01147 struct ast_channel *ast_waitfor_n(struct ast_channel **chan, int n, int *ms);
01148 
01149 /*! \brief Waits for input on an fd
01150    This version works on fd's only.  Be careful with it. */
01151 int ast_waitfor_n_fd(int *fds, int n, int *ms, int *exception);
01152 
01153 
01154 /*! \brief Reads a frame
01155  * \param chan channel to read a frame from
01156  * \return Returns a frame, or NULL on error.  If it returns NULL, you
01157    best just stop reading frames and assume the channel has been
01158    disconnected. */
01159 struct ast_frame *ast_read(struct ast_channel *chan);
01160 
01161 /*! \brief Reads a frame, returning AST_FRAME_NULL frame if audio. 
01162    \param chan channel to read a frame from
01163    \return  Returns a frame, or NULL on error.  If it returns NULL, you
01164       best just stop reading frames and assume the channel has been
01165       disconnected.  
01166    \note Audio is replaced with AST_FRAME_NULL to avoid 
01167    transcode when the resulting audio is not necessary. */
01168 struct ast_frame *ast_read_noaudio(struct ast_channel *chan);
01169 
01170 /*! \brief Write a frame to a channel 
01171  * This function writes the given frame to the indicated channel.
01172  * \param chan destination channel of the frame
01173  * \param frame frame that will be written
01174  * \return It returns 0 on success, -1 on failure.
01175  */
01176 int ast_write(struct ast_channel *chan, struct ast_frame *frame);
01177 
01178 /*! \brief Write video frame to a channel 
01179  * This function writes the given frame to the indicated channel.
01180  * \param chan destination channel of the frame
01181  * \param frame frame that will be written
01182  * \return It returns 1 on success, 0 if not implemented, and -1 on failure.
01183  */
01184 int ast_write_video(struct ast_channel *chan, struct ast_frame *frame);
01185 
01186 /*! \brief Write text frame to a channel 
01187  * This function writes the given frame to the indicated channel.
01188  * \param chan destination channel of the frame
01189  * \param frame frame that will be written
01190  * \return It returns 1 on success, 0 if not implemented, and -1 on failure.
01191  */
01192 int ast_write_text(struct ast_channel *chan, struct ast_frame *frame);
01193 
01194 /*! \brief Send empty audio to prime a channel driver */
01195 int ast_prod(struct ast_channel *chan);
01196 
01197 /*! \brief Sets read format on channel chan
01198  * Set read format for channel to whichever component of "format" is best. 
01199  * \param chan channel to change
01200  * \param format format to change to
01201  * \return Returns 0 on success, -1 on failure
01202  */
01203 int ast_set_read_format(struct ast_channel *chan, int format);
01204 
01205 /*! \brief Sets write format on channel chan
01206  * Set write format for channel to whichever component of "format" is best. 
01207  * \param chan channel to change
01208  * \param format new format for writing
01209  * \return Returns 0 on success, -1 on failure
01210  */
01211 int ast_set_write_format(struct ast_channel *chan, int format);
01212 
01213 /*! 
01214  * \brief Sends text to a channel 
01215  *
01216  * \param chan channel to act upon
01217  * \param text string of text to send on the channel
01218  *
01219  * Write text to a display on a channel
01220  *
01221  * \note The channel does not need to be locked before calling this function.
01222  *
01223  * \retval 0 on success 
01224  * \retval -1 on failure
01225  */
01226 int ast_sendtext(struct ast_channel *chan, const char *text);
01227 
01228 /*! \brief Receives a text character from a channel
01229  * \param chan channel to act upon
01230  * \param timeout timeout in milliseconds (0 for infinite wait)
01231  * Read a char of text from a channel
01232  * Returns 0 on success, -1 on failure
01233  */
01234 int ast_recvchar(struct ast_channel *chan, int timeout);
01235 
01236 /*! \brief Send a DTMF digit to a channel
01237  * Send a DTMF digit to a channel.
01238  * \param chan channel to act upon
01239  * \param digit the DTMF digit to send, encoded in ASCII
01240  * \param duration the duration of the digit ending in ms
01241  * \return Returns 0 on success, -1 on failure
01242  */
01243 int ast_senddigit(struct ast_channel *chan, char digit, unsigned int duration);
01244 
01245 /*! \brief Send a DTMF digit to a channel
01246  * Send a DTMF digit to a channel.
01247  * \param chan channel to act upon
01248  * \param digit the DTMF digit to send, encoded in ASCII
01249  * \return Returns 0 on success, -1 on failure
01250  */
01251 int ast_senddigit_begin(struct ast_channel *chan, char digit);
01252 
01253 /*! \brief Send a DTMF digit to a channel
01254 
01255  * Send a DTMF digit to a channel.
01256  * \param chan channel to act upon
01257  * \param digit the DTMF digit to send, encoded in ASCII
01258  * \param duration the duration of the digit ending in ms
01259  * \return Returns 0 on success, -1 on failure
01260  */
01261 int ast_senddigit_end(struct ast_channel *chan, char digit, unsigned int duration);
01262 
01263 /*! \brief Receives a text string from a channel
01264  * Read a string of text from a channel
01265  * \param chan channel to act upon
01266  * \param timeout timeout in milliseconds (0 for infinite wait)
01267  * \return the received text, or NULL to signify failure.
01268  */
01269 char *ast_recvtext(struct ast_channel *chan, int timeout);
01270 
01271 /*! \brief Browse channels in use
01272  * Browse the channels currently in use 
01273  * \param prev where you want to start in the channel list
01274  * \return Returns the next channel in the list, NULL on end.
01275  *    If it returns a channel, that channel *has been locked*!
01276  */
01277 struct ast_channel *ast_channel_walk_locked(const struct ast_channel *prev);
01278 
01279 /*! \brief Get channel by name or uniqueid (locks channel) */
01280 struct ast_channel *ast_get_channel_by_name_locked(const char *chan);
01281 
01282 /*! \brief Get channel by name or uniqueid prefix (locks channel) */
01283 struct ast_channel *ast_get_channel_by_name_prefix_locked(const char *name, const int namelen);
01284 
01285 /*! \brief Get channel by name or uniqueid prefix (locks channel) */
01286 struct ast_channel *ast_walk_channel_by_name_prefix_locked(const struct ast_channel *chan, const char *name, const int namelen);
01287 
01288 /*! \brief Get channel by exten (and optionally context) and lock it */
01289 struct ast_channel *ast_get_channel_by_exten_locked(const char *exten, const char *context);
01290 
01291 /*! \brief Get next channel by exten (and optionally context) and lock it */
01292 struct ast_channel *ast_walk_channel_by_exten_locked(const struct ast_channel *chan, const char *exten,
01293                        const char *context);
01294 
01295 /*! ! \brief Waits for a digit
01296  * \param c channel to wait for a digit on
01297  * \param ms how many milliseconds to wait
01298  * \return Returns <0 on error, 0 on no entry, and the digit on success. */
01299 int ast_waitfordigit(struct ast_channel *c, int ms);
01300 
01301 /*! \brief Wait for a digit
01302  Same as ast_waitfordigit() with audio fd for outputting read audio and ctrlfd to monitor for reading. 
01303  * \param c channel to wait for a digit on
01304  * \param ms how many milliseconds to wait
01305  * \param audiofd audio file descriptor to write to if audio frames are received
01306  * \param ctrlfd control file descriptor to monitor for reading
01307  * \return Returns 1 if ctrlfd becomes available */
01308 int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int ctrlfd);
01309 
01310 /*! Reads multiple digits 
01311  * \param c channel to read from
01312  * \param s string to read in to.  Must be at least the size of your length
01313  * \param len how many digits to read (maximum)
01314  * \param timeout how long to timeout between digits
01315  * \param rtimeout timeout to wait on the first digit
01316  * \param enders digits to end the string
01317  * Read in a digit string "s", max length "len", maximum timeout between 
01318    digits "timeout" (-1 for none), terminated by anything in "enders".  Give them rtimeout
01319    for the first digit.  Returns 0 on normal return, or 1 on a timeout.  In the case of
01320    a timeout, any digits that were read before the timeout will still be available in s.  
01321    RETURNS 2 in full version when ctrlfd is available, NOT 1*/
01322 int ast_readstring(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders);
01323 int ast_readstring_full(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders, int audiofd, int ctrlfd);
01324 
01325 /*! \brief Report DTMF on channel 0 */
01326 #define AST_BRIDGE_DTMF_CHANNEL_0      (1 << 0)    
01327 /*! \brief Report DTMF on channel 1 */
01328 #define AST_BRIDGE_DTMF_CHANNEL_1      (1 << 1)    
01329 /*! \brief Return all voice frames on channel 0 */
01330 #define AST_BRIDGE_REC_CHANNEL_0    (1 << 2)    
01331 /*! \brief Return all voice frames on channel 1 */
01332 #define AST_BRIDGE_REC_CHANNEL_1    (1 << 3)    
01333 /*! \brief Ignore all signal frames except NULL */
01334 #define AST_BRIDGE_IGNORE_SIGS         (1 << 4)    
01335 
01336 
01337 /*! \brief Makes two channel formats compatible 
01338  * \param c0 first channel to make compatible
01339  * \param c1 other channel to make compatible
01340  * Set two channels to compatible formats -- call before ast_channel_bridge in general .  
01341  * \return Returns 0 on success and -1 if it could not be done */
01342 int ast_channel_make_compatible(struct ast_channel *c0, struct ast_channel *c1);
01343 
01344 /*! Bridge two channels together (early)
01345  * \param c0 first channel to bridge
01346  * \param c1 second channel to bridge
01347  * Bridge two channels (c0 and c1) together early. This implies either side may not be answered yet.
01348  * \return Returns 0 on success and -1 if it could not be done */
01349 int ast_channel_early_bridge(struct ast_channel *c0, struct ast_channel *c1);
01350 
01351 /*! Bridge two channels together 
01352  * \param c0 first channel to bridge
01353  * \param c1 second channel to bridge
01354  * \param config config for the channels
01355  * \param fo destination frame(?)
01356  * \param rc destination channel(?)
01357  * Bridge two channels (c0 and c1) together.  If an important frame occurs, we return that frame in
01358    *rf (remember, it could be NULL) and which channel (0 or 1) in rc */
01359 /* int ast_channel_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc); */
01360 int ast_channel_bridge(struct ast_channel *c0,struct ast_channel *c1,
01361    struct ast_bridge_config *config, struct ast_frame **fo, struct ast_channel **rc);
01362 
01363 /*! 
01364  * \brief Weird function made for call transfers
01365  *
01366  * \param original channel to make a copy of
01367  * \param clone copy of the original channel
01368  *
01369  * This is a very strange and freaky function used primarily for transfer.  Suppose that
01370  * "original" and "clone" are two channels in random situations.  This function takes
01371  * the guts out of "clone" and puts them into the "original" channel, then alerts the
01372  * channel driver of the change, asking it to fixup any private information (like the
01373  * p->owner pointer) that is affected by the change.  The physical layer of the original
01374  * channel is hung up.  
01375  *
01376  * \note Neither channel passed here needs to be locked before calling this function.
01377  */
01378 int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clone);
01379 
01380 /*! Gives the string form of a given cause code */
01381 /*! 
01382  * \param state cause to get the description of
01383  * Give a name to a cause code
01384  * Returns the text form of the binary cause code given
01385  */
01386 const char *ast_cause2str(int state) attribute_pure;
01387 
01388 /*! Convert the string form of a cause code to a number */
01389 /*! 
01390  * \param name string form of the cause
01391  * Returns the cause code
01392  */
01393 int ast_str2cause(const char *name) attribute_pure;
01394 
01395 /*! Gives the string form of a given channel state */
01396 /*! 
01397  * \param ast_channel_state state to get the name of
01398  * Give a name to a state 
01399  * Returns the text form of the binary state given
01400  */
01401 const char *ast_state2str(enum ast_channel_state);
01402 
01403 /*! Gives the string form of a given transfer capability */
01404 /*!
01405  * \param transfercapability transfercapabilty to get the name of
01406  * Give a name to a transfercapbility
01407  * See above
01408  * Returns the text form of the binary transfer capability
01409  */
01410 char *ast_transfercapability2str(int transfercapability) attribute_const;
01411 
01412 /* Options: Some low-level drivers may implement "options" allowing fine tuning of the
01413    low level channel.  See frame.h for options.  Note that many channel drivers may support
01414    none or a subset of those features, and you should not count on this if you want your
01415    asterisk application to be portable.  They're mainly useful for tweaking performance */
01416 
01417 /*! Sets an option on a channel */
01418 /*! 
01419  * \param channel channel to set options on
01420  * \param option option to change
01421  * \param data data specific to option
01422  * \param datalen length of the data
01423  * \param block blocking or not
01424  * Set an option on a channel (see frame.h), optionally blocking awaiting the reply 
01425  * Returns 0 on success and -1 on failure
01426  */
01427 int ast_channel_setoption(struct ast_channel *channel, int option, void *data, int datalen, int block);
01428 
01429 /*! Pick the best codec  */
01430 /* Choose the best codec...  Uhhh...   Yah. */
01431 int ast_best_codec(int fmts);
01432 
01433 
01434 /*! Checks the value of an option */
01435 /*! 
01436  * Query the value of an option
01437  * Works similarly to setoption except only reads the options.
01438  */
01439 int ast_channel_queryoption(struct ast_channel *channel, int option, void *data, int *datalen, int block);
01440 
01441 /*! Checks for HTML support on a channel */
01442 /*! Returns 0 if channel does not support HTML or non-zero if it does */
01443 int ast_channel_supports_html(struct ast_channel *channel);
01444 
01445 /*! Sends HTML on given channel */
01446 /*! Send HTML or URL on link.  Returns 0 on success or -1 on failure */
01447 int ast_channel_sendhtml(struct ast_channel *channel, int subclass, const char *data, int datalen);
01448 
01449 /*! Sends a URL on a given link */
01450 /*! Send URL on link.  Returns 0 on success or -1 on failure */
01451 int ast_channel_sendurl(struct ast_channel *channel, const char *url);
01452 
01453 /*! Defers DTMF */
01454 /*! Defer DTMF so that you only read things like hangups and audio.  Returns
01455    non-zero if channel was already DTMF-deferred or 0 if channel is just now
01456    being DTMF-deferred */
01457 int ast_channel_defer_dtmf(struct ast_channel *chan);
01458 
01459 /*! Undo defer.  ast_read will return any dtmf characters that were queued */
01460 void ast_channel_undefer_dtmf(struct ast_channel *chan);
01461 
01462 /*! Initiate system shutdown -- prevents new channels from being allocated.
01463     If "hangup" is non-zero, all existing channels will receive soft
01464      hangups */
01465 void ast_begin_shutdown(int hangup);
01466 
01467 /*! Cancels an existing shutdown and returns to normal operation */
01468 void ast_cancel_shutdown(void);
01469 
01470 /*! Returns number of active/allocated channels */
01471 int ast_active_channels(void);
01472 
01473 /*! Returns non-zero if Asterisk is being shut down */
01474 int ast_shutting_down(void);
01475 
01476 /*! Activate a given generator */
01477 int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params);
01478 
01479 /*! Deactivate an active generator */
01480 void ast_deactivate_generator(struct ast_channel *chan);
01481 
01482 /*!
01483  * \brief Set caller ID number, name and ANI
01484  *
01485  * \note The channel does not need to be locked before calling this function.
01486  */
01487 void ast_set_callerid(struct ast_channel *chan, const char *cid_num, const char *cid_name, const char *cid_ani);
01488 
01489 /*! Set the file descriptor on the channel */
01490 void ast_channel_set_fd(struct ast_channel *chan, int which, int fd);
01491 
01492 /*! Add a channel to an optimized waitfor */
01493 void ast_poll_channel_add(struct ast_channel *chan0, struct ast_channel *chan1);
01494 
01495 /*! Delete a channel from an optimized waitfor */
01496 void ast_poll_channel_del(struct ast_channel *chan0, struct ast_channel *chan1);
01497 
01498 /*! Start a tone going */
01499 int ast_tonepair_start(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01500 /*! Stop a tone from playing */
01501 void ast_tonepair_stop(struct ast_channel *chan);
01502 /*! Play a tone pair for a given amount of time */
01503 int ast_tonepair(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
01504 
01505 /*!
01506  * \brief Automatically service a channel for us... 
01507  *
01508  * \retval 0 success
01509  * \retval -1 failure, or the channel is already being autoserviced
01510  */
01511 int ast_autoservice_start(struct ast_channel *chan);
01512 
01513 /*! 
01514  * \brief Stop servicing a channel for us...  
01515  *
01516  * \note if chan is locked prior to calling ast_autoservice_stop, it
01517  * is likely that there will be a deadlock between the thread that calls
01518  * ast_autoservice_stop and the autoservice thread. It is important
01519  * that chan is not locked prior to this call
01520  *
01521  * \retval 0 success
01522  * \retval -1 error, or the channel has been hungup 
01523  */
01524 int ast_autoservice_stop(struct ast_channel *chan);
01525 
01526 /* If built with dahdi optimizations, force a scheduled expiration on the
01527    timer fd, at which point we call the callback function / data */
01528 int ast_settimeout(struct ast_channel *c, int samples, int (*func)(const void *data), void *data);
01529 
01530 /*!   \brief Transfer a channel (if supported).  Returns -1 on error, 0 if not supported
01531    and 1 if supported and requested 
01532    \param chan current channel
01533    \param dest destination extension for transfer
01534 */
01535 int ast_transfer(struct ast_channel *chan, char *dest);
01536 
01537 /*!   \brief  Start masquerading a channel
01538    XXX This is a seriously whacked out operation.  We're essentially putting the guts of
01539            the clone channel into the original channel.  Start by killing off the original
01540            channel's backend.   I'm not sure we're going to keep this function, because
01541            while the features are nice, the cost is very high in terms of pure nastiness. XXX
01542    \param chan    Channel to masquerade
01543 */
01544 int ast_do_masquerade(struct ast_channel *chan);
01545 
01546 /*!   \brief Find bridged channel 
01547    \param chan Current channel
01548 */
01549 struct ast_channel *ast_bridged_channel(struct ast_channel *chan);
01550 
01551 /*!
01552   \brief Inherits channel variable from parent to child channel
01553   \param parent Parent channel
01554   \param child Child channel
01555 
01556   Scans all channel variables in the parent channel, looking for those
01557   that should be copied into the child channel.
01558   Variables whose names begin with a single '_' are copied into the
01559   child channel with the prefix removed.
01560   Variables whose names begin with '__' are copied into the child
01561   channel with their names unchanged.
01562 */
01563 void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child);
01564 
01565 /*!
01566   \brief adds a list of channel variables to a channel
01567   \param chan the channel
01568   \param vars a linked list of variables
01569 
01570   Variable names can be for a regular channel variable or a dialplan function
01571   that has the ability to be written to.
01572 */
01573 void ast_set_variables(struct ast_channel *chan, struct ast_variable *vars);
01574 
01575 /*!
01576   \brief An opaque 'object' structure use by silence generators on channels.
01577  */
01578 struct ast_silence_generator;
01579 
01580 /*!
01581   \brief Starts a silence generator on the given channel.
01582   \param chan The channel to generate silence on
01583   \return An ast_silence_generator pointer, or NULL if an error occurs
01584 
01585   This function will cause SLINEAR silence to be generated on the supplied
01586   channel until it is disabled; if the channel cannot be put into SLINEAR
01587   mode then the function will fail.
01588 
01589   The pointer returned by this function must be preserved and passed to
01590   ast_channel_stop_silence_generator when you wish to stop the silence
01591   generation.
01592  */
01593 struct ast_silence_generator *ast_channel_start_silence_generator(struct ast_channel *chan);
01594 
01595 /*!
01596   \brief Stops a previously-started silence generator on the given channel.
01597   \param chan The channel to operate on
01598   \param state The ast_silence_generator pointer return by a previous call to
01599   ast_channel_start_silence_generator.
01600   \return nothing
01601 
01602   This function will stop the operating silence generator and return the channel
01603   to its previous write format.
01604  */
01605 void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state);
01606 
01607 /*!
01608   \brief Check if the channel can run in internal timing mode.
01609   \param chan The channel to check
01610   \return boolean
01611 
01612   This function will return 1 if internal timing is enabled and the timing
01613   device is available.
01614  */
01615 int ast_internal_timing_enabled(struct ast_channel *chan);
01616 
01617 /* Misc. functions below */
01618 
01619 /*! \brief if fd is a valid descriptor, set *pfd with the descriptor
01620  * \return Return 1 (not -1!) if added, 0 otherwise (so we can add the
01621  * return value to the index into the array)
01622  */
01623 static inline int ast_add_fd(struct pollfd *pfd, int fd)
01624 {
01625    pfd->fd = fd;
01626    pfd->events = POLLIN | POLLPRI;
01627    return fd >= 0;
01628 }
01629 
01630 /*! \brief Helper function for migrating select to poll */
01631 static inline int ast_fdisset(struct pollfd *pfds, int fd, int max, int *start)
01632 {
01633    int x;
01634    int dummy=0;
01635 
01636    if (fd < 0)
01637       return 0;
01638    if (!start)
01639       start = &dummy;
01640    for (x = *start; x<max; x++)
01641       if (pfds[x].fd == fd) {
01642          if (x == *start)
01643             (*start)++;
01644          return pfds[x].revents;
01645       }
01646    return 0;
01647 }
01648 
01649 #ifndef HAVE_TIMERSUB
01650 static inline void timersub(struct timeval *tvend, struct timeval *tvstart, struct timeval *tvdiff)
01651 {
01652    tvdiff->tv_sec = tvend->tv_sec - tvstart->tv_sec;
01653    tvdiff->tv_usec = tvend->tv_usec - tvstart->tv_usec;
01654    if (tvdiff->tv_usec < 0) {
01655       tvdiff->tv_sec --;
01656       tvdiff->tv_usec += 1000000;
01657    }
01658 
01659 }
01660 #endif
01661 
01662 /*! \brief Waits for activity on a group of channels 
01663  * \param nfds the maximum number of file descriptors in the sets
01664  * \param rfds file descriptors to check for read availability
01665  * \param wfds file descriptors to check for write availability
01666  * \param efds file descriptors to check for exceptions (OOB data)
01667  * \param tvp timeout while waiting for events
01668  * This is the same as a standard select(), except it guarantees the
01669  * behaviour where the passed struct timeval is updated with how much
01670  * time was not slept while waiting for the specified events
01671  */
01672 static inline int ast_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *tvp)
01673 {
01674 #ifdef __linux__
01675    return select(nfds, rfds, wfds, efds, tvp);
01676 #else
01677    if (tvp) {
01678       struct timeval tv, tvstart, tvend, tvlen;
01679       int res;
01680 
01681       tv = *tvp;
01682       gettimeofday(&tvstart, NULL);
01683       res = select(nfds, rfds, wfds, efds, tvp);
01684       gettimeofday(&tvend, NULL);
01685       timersub(&tvend, &tvstart, &tvlen);
01686       timersub(&tv, &tvlen, tvp);
01687       if (tvp->tv_sec < 0 || (tvp->tv_sec == 0 && tvp->tv_usec < 0)) {
01688          tvp->tv_sec = 0;
01689          tvp->tv_usec = 0;
01690       }
01691       return res;
01692    }
01693    else
01694       return select(nfds, rfds, wfds, efds, NULL);
01695 #endif
01696 }
01697 
01698 /*! \brief Retrieves the current T38 state of a channel */
01699 static inline enum ast_t38_state ast_channel_get_t38_state(struct ast_channel *chan)
01700 {
01701    enum ast_t38_state state = T38_STATE_UNAVAILABLE;
01702    int datalen = sizeof(state);
01703 
01704    ast_channel_queryoption(chan, AST_OPTION_T38_STATE, &state, &datalen, 0);
01705 
01706    return state;
01707 }
01708 
01709 #define CHECK_BLOCKING(c) do {    \
01710    if (ast_test_flag(c, AST_FLAG_BLOCKING)) {\
01711       if (option_debug) \
01712          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); \
01713    } else { \
01714       (c)->blocker = pthread_self(); \
01715       (c)->blockproc = __PRETTY_FUNCTION__; \
01716       ast_set_flag(c, AST_FLAG_BLOCKING); \
01717    } } while (0)
01718 
01719 ast_group_t ast_get_group(const char *s);
01720 
01721 /*! \brief print call- and pickup groups into buffer */
01722 char *ast_print_group(char *buf, int buflen, ast_group_t group);
01723 
01724 /*! \brief Convert enum channelreloadreason to text string for manager event
01725    \param reason  Enum channelreloadreason - reason for reload (manager, cli, start etc)
01726 */
01727 const char *channelreloadreason2txt(enum channelreloadreason reason);
01728 
01729 /*! \brief return an ast_variable list of channeltypes */
01730 struct ast_variable *ast_channeltype_list(void);
01731 
01732 /*!
01733   \brief return an english explanation of the code returned thru __ast_request_and_dial's 'outstate' argument
01734   \param reason  The integer argument, usually taken from AST_CONTROL_ macros
01735   \return char pointer explaining the code
01736  */
01737 const char *ast_channel_reason2str(int reason);
01738 
01739 /*! \brief channel group info
01740  */
01741 struct ast_group_info {
01742         struct ast_channel *chan;
01743         char *category;
01744         char *group;
01745         AST_LIST_ENTRY(ast_group_info) group_list;   
01746 };
01747 
01748 
01749 #if defined(__cplusplus) || defined(c_plusplus)
01750 }
01751 #endif
01752 
01753 #endif /* _ASTERISK_CHANNEL_H */

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