Asterisk.org: Developer Documentation (28 Oct 2009)

Wed Oct 28 15:47:53 2009

## Asterisk developer's documentation

# channel.h

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    00001 /*
    00002  * Asterisk -- An open source telephony toolkit.
    00003  *
    00004  * Copyright (C) 1999 - 2005, 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 \ref channel_drivers - Implemented channel drivers
    00082    \arg \ref Def_Frame Asterisk Multimedia Frames
    00083
    00084 */
    00085
    00086 #ifndef _ASTERISK_CHANNEL_H
    00087 #define _ASTERISK_CHANNEL_H
    00088
    00089 #include <unistd.h>
    00090 #include <setjmp.h>
    00091 #ifdef POLLCOMPAT
    00092 #include "asterisk/poll-compat.h"
    00093 #else
    00094 #include <sys/poll.h>
    00095 #endif
    00096
    00097 #if defined(__cplusplus) || defined(c_plusplus)
    00098 extern "C" {
    00099 #endif
    00100
    00101 /*! Max length of an extension */
    00102 #define AST_MAX_EXTENSION  80
    00103
    00104 #define AST_MAX_CONTEXT    80
    00105
    00106 #define AST_CHANNEL_NAME   80
    00107
    00108 #include "asterisk/compat.h"
    00109 #include "asterisk/frame.h"
    00110 #include "asterisk/sched.h"
    00111 #include "asterisk/chanvars.h"
    00112 #include "asterisk/config.h"
    00113 #include "asterisk/lock.h"
    00114 #include "asterisk/cdr.h"
    00115 #include "asterisk/utils.h"
    00116 #include "asterisk/linkedlists.h"
    00117
    00118 #define MAX_LANGUAGE    20
    00119
    00120 #define MAX_MUSICCLASS     20
    00121
    00122 #define AST_MAX_FDS     8
    00123
    00124 enum ast_bridge_result {
    00125    AST_BRIDGE_COMPLETE = 0,
    00126    AST_BRIDGE_FAILED = -1,
    00127    AST_BRIDGE_FAILED_NOWARN = -2,
    00128    AST_BRIDGE_RETRY = -3,
    00129 };
    00130
    00131 typedef unsigned long long ast_group_t;
    00132
    00133 struct ast_generator {
    00134    void *(*alloc)(struct ast_channel *chan, void *params);
    00135    void (*release)(struct ast_channel *chan, void *data);
    00136    int (*generate)(struct ast_channel *chan, void *data, int len, int samples);
    00137 };
    00138
    00139 /*! Structure for all kinds of caller ID identifications */
    00140 struct ast_callerid {
    00141    /*! Malloc'd Dialed Number Identifier */
    00142    char *cid_dnid;
    00143    /*! Malloc'd Caller Number */
    00144    char *cid_num;
    00145    /*! Malloc'd Caller Name */
    00146    char *cid_name;
    00147    /*! Malloc'd ANI */
    00148    char *cid_ani;
    00149    /*! Malloc'd RDNIS */
    00150    char *cid_rdnis;
    00151    /*! Callerid presentation/screening */
    00152    int cid_pres;
    00153    /*! Callerid ANI 2 (Info digits) */
    00154    int cid_ani2;
    00155    /*! Callerid Type of Number */
    00156    int cid_ton;
    00157    /*! Callerid Transit Network Select */
    00158    int cid_tns;
    00159 };
    00160
    00161 /*! Structure to describe a channel "technology", ie a channel driver
    00162    See
    00163    \arg chan_iax2.c - The Inter-Asterisk exchange protocol
    00164    \arg chan_sip.c - The SIP channel driver
    00165    \arg chan_zap.c - PSTN connectivity (TDM, PRI, T1/E1, FXO, FXS)
    00166
    00167    If you develop your own channel driver, this is where you
    00168    tell the PBX at registration of your driver what properties
    00169    this driver supports and where different callbacks are
    00170    implemented.
    00171 */
    00172
    00173
    00174 struct ast_channel_tech {
    00175    const char * const type;
    00176    const char * const description;
    00177
    00178    /*! Bitmap of formats this channel can handle */
    00179    int capabilities;
    00180
    00181    /*! Technology Properties */
    00182    int properties;
    00183
    00184    /*! Requester - to set up call data structures (pvt's) */
    00185    struct ast_channel *(* const requester)(const char *type, int format, void *data, int *cause);
    00186
    00187    /*! Devicestate call back */
    00188    int (* const devicestate)(void *data);
    00189
    00190    /*! Send a literal DTMF digit */
    00191    int (* const send_digit)(struct ast_channel *chan, char digit);
    00192
    00193    /*! Call a given phone number (address, etc), but don't
    00194       take longer than timeout seconds to do so.  */
    00195    int (* const call)(struct ast_channel *chan, char *addr, int timeout);
    00196
    00197    /*! Hangup (and possibly destroy) the channel */
    00198    int (* const hangup)(struct ast_channel *chan);
    00199
    00200    /*! Answer the channel */
    00201    int (* const answer)(struct ast_channel *chan);
    00202
    00203    /*! Read a frame, in standard format (see frame.h) */
    00204    struct ast_frame * (* const read)(struct ast_channel *chan);
    00205
    00206    /*! Write a frame, in standard format (see frame.h) */
    00207    int (* const write)(struct ast_channel *chan, struct ast_frame *frame);
    00208
    00209    /*! Display or transmit text */
    00210    int (* const send_text)(struct ast_channel *chan, const char *text);
    00211
    00212    /*! Display or send an image */
    00213    int (* const send_image)(struct ast_channel *chan, struct ast_frame *frame);
    00214
    00215    /*! Send HTML data */
    00216    int (* const send_html)(struct ast_channel *chan, int subclass, const char *data, int len);
    00217
    00218    /*! Handle an exception, reading a frame */
    00219    struct ast_frame * (* const exception)(struct ast_channel *chan);
    00220
    00221    /*! Bridge two channels of the same type together */
    00222    enum ast_bridge_result (* const bridge)(struct ast_channel *c0, struct ast_channel *c1, int flags,
    00223                   struct ast_frame **fo, struct ast_channel **rc, int timeoutms);
    00224
    00225    /*! Indicate a particular condition (e.g. AST_CONTROL_BUSY or AST_CONTROL_RINGING or AST_CONTROL_CONGESTION */
    00226    int (* const indicate)(struct ast_channel *c, int condition);
    00227
    00228    /*! Fix up a channel:  If a channel is consumed, this is called.  Basically update any ->owner links */
    00229    int (* const fixup)(struct ast_channel *oldchan, struct ast_channel *newchan);
    00230
    00231    /*! Set a given option */
    00232    int (* const setoption)(struct ast_channel *chan, int option, void *data, int datalen);
    00233
    00234    /*! Query a given option */
    00235    int (* const queryoption)(struct ast_channel *chan, int option, void *data, int *datalen);
    00236
    00237    /*! Blind transfer other side (see app_transfer.c and ast_transfer() */
    00238    int (* const transfer)(struct ast_channel *chan, const char *newdest);
    00239
    00240    /*! Write a frame, in standard format */
    00241    int (* const write_video)(struct ast_channel *chan, struct ast_frame *frame);
    00242
    00243    /*! Find bridged channel */
    00244    struct ast_channel *(* const bridged_channel)(struct ast_channel *chan, struct ast_channel *bridge);
    00245 };
    00246
    00247 struct ast_channel_spy_list;
    00248
    00249 /*! Main Channel structure associated with a channel.
    00250  * This is the side of it mostly used by the pbx and call management.
    00251  */
    00252 struct ast_channel {
    00253    /*! ASCII unique channel name */
    00254    char name[AST_CHANNEL_NAME];
    00255
    00256    /*! Technology (point to channel driver) */
    00257    const struct ast_channel_tech *tech;
    00258
    00259    /*! Private data used by the technology driver */
    00260    void *tech_pvt;
    00261
    00262    /*! Language requested for voice prompts */
    00263    char language[MAX_LANGUAGE];
    00264    /*! Type of channel */
    00265    const char *type;
    00266    /*! File descriptor for channel -- Drivers will poll on these file descriptors, so at least one must be non -1.  */
    00267    int fds[AST_MAX_FDS];
    00268
    00269    /*! Default music class */
    00270    char musicclass[MAX_MUSICCLASS];
    00271    /*! Music State*/
    00272    void *music_state;
    00273    /*! Current generator data if there is any */
    00274    void *generatordata;
    00275    /*! Current active data generator */
    00276    struct ast_generator *generator;
    00277
    00278    /*! Who are we bridged to, if we're bridged. Who is proxying for us,
    00279      if we are proxied (i.e. chan_agent).
    00280      Do not access directly, use ast_bridged_channel(chan) */
    00281    struct ast_channel *_bridge;
    00282    /*! Channel that will masquerade as us */
    00283    struct ast_channel *masq;
    00284    /*! Who we are masquerading as */
    00285    struct ast_channel *masqr;
    00286    /*! Call Detail Record Flags */
    00287    int cdrflags;
    00288    /*! Whether or not we have been hung up...  Do not set this value
    00289        directly, use ast_softhangup */
    00290    int _softhangup;
    00291    /*! Non-zero, set to actual time when channel is to be hung up */
    00292    time_t   whentohangup;
    00293    /*! If anyone is blocking, this is them */
    00294    pthread_t blocker;
    00295    /*! Lock, can be used to lock a channel for some operations */
    00296    ast_mutex_t lock;
    00297    /*! Procedure causing blocking */
    00298    const char *blockproc;
    00299
    00300    /*! Current application */
    00301    char *appl;
    00302    /*! Data passed to current application */
    00303    char *data;
    00304
    00305    /*! Which fd had an event detected on */
    00306    int fdno;
    00307    /*! Schedule context */
    00308    struct sched_context *sched;
    00309    /*! For streaming playback, the schedule ID */
    00310    int streamid;
    00311    /*! Stream itself. */
    00312    struct ast_filestream *stream;
    00313    /*! For streaming video playback, the schedule ID */
    00314    int vstreamid;
    00315    /*! Video Stream itself. */
    00316    struct ast_filestream *vstream;
    00317    /*! Original writer format */
    00318    int oldwriteformat;
    00319
    00320    /*! Timing fd */
    00321    int timingfd;
    00322    int (*timingfunc)(void *data);
    00323    void *timingdata;
    00324
    00325    /*! State of line -- Don't write directly, use ast_setstate */
    00326    int _state;
    00327    /*! Number of rings so far */
    00328    int rings;
    00329
    00330    /*! Kinds of data this channel can natively handle */
    00331    int nativeformats;
    00332    /*! Requested read format */
    00333    int readformat;
    00334    /*! Requested write format */
    00335    int writeformat;
    00336
    00337    struct ast_callerid cid;
    00338
    00339    /*! Current extension context */
    00340    char context[AST_MAX_CONTEXT];
    00341    /*! Current non-macro context */
    00342    char macrocontext[AST_MAX_CONTEXT];
    00343    /*! Current non-macro extension */
    00344    char macroexten[AST_MAX_EXTENSION];
    00345    /*! Current non-macro priority */
    00346    int macropriority;
    00347    /*! Current extension number */
    00348    char exten[AST_MAX_EXTENSION];
    00349    /* Current extension priority */
    00350    int priority;
    00351    /*! Any/all queued DTMF characters */
    00352    char dtmfq[AST_MAX_EXTENSION];
    00353    /*! DTMF frame */
    00354    struct ast_frame dtmff;
    00355
    00356    /*! PBX private structure */
    00357    struct ast_pbx *pbx;
    00358    /*! Set BEFORE PBX is started to determine AMA flags */
    00359    int amaflags;
    00360    /*! Account code for billing */
    00361    char accountcode[AST_MAX_ACCOUNT_CODE];
    00362    /*! Call Detail Record */
    00363    struct ast_cdr *cdr;
    00364    /*! Whether or not ADSI is detected on CPE */
    00365    int adsicpe;
    00366    /*! Where to forward to if asked to dial on this interface */
    00367    char call_forward[AST_MAX_EXTENSION];
    00368
    00369    /*! Tone zone as set in indications.conf */
    00370    struct tone_zone *zone;
    00371
    00372    /* Channel monitoring */
    00373    struct ast_channel_monitor *monitor;
    00374
    00375    /*! Track the read/written samples for monitor use */
    00376    unsigned long insmpl;
    00377    unsigned long outsmpl;
    00378
    00379    /* Frames in/out counters */
    00380    unsigned int fin;
    00381    unsigned int fout;
    00382
    00383    /* Unique Channel Identifier */
    00384    char uniqueid[32];
    00385
    00386    /* Why is the channel hanged up */
    00387    int hangupcause;
    00388
    00389    /* A linked list for variables */
    00390    struct varshead varshead;
    00391
    00392    ast_group_t callgroup;
    00393    ast_group_t pickupgroup;
    00394
    00395    /*! channel flags of AST_FLAG_ type */
    00396    unsigned int flags;
    00397
    00398    /*! ISDN Transfer Capbility - AST_FLAG_DIGITAL is not enough */
    00399    unsigned short transfercapability;
    00400
    00401    struct ast_frame *readq;
    00402    int alertpipe[2];
    00403    /*! Write translation path */
    00404    struct ast_trans_pvt *writetrans;
    00405    /*! Read translation path */
    00406    struct ast_trans_pvt *readtrans;
    00407    /*! Raw read format */
    00408    int rawreadformat;
    00409    /*! Raw write format */
    00410    int rawwriteformat;
    00411
    00412    /*! Chan Spy stuff */
    00413    struct ast_channel_spy_list *spies;
    00414
    00415    /*! For easy linking */
    00416    struct ast_channel *next;
    00417 };
    00418
    00419 /* \defgroup chanprop Channel tech properties:
    00420    \brief Channels have this property if they can accept input with jitter; i.e. most VoIP channels */
    00421 /* @{ */
    00422 #define AST_CHAN_TP_WANTSJITTER  (1 << 0)
    00423
    00424 /* This flag has been deprecated by the transfercapbilty data member in struct ast_channel */
    00425 /* #define AST_FLAG_DIGITAL   (1 << 0) */ /* if the call is a digital ISDN call */
    00426 #define AST_FLAG_DEFER_DTMF   (1 << 1) /*!< if dtmf should be deferred */
    00427 #define AST_FLAG_WRITE_INT (1 << 2) /*!< if write should be interrupt generator */
    00428 #define AST_FLAG_BLOCKING  (1 << 3) /*!< if we are blocking */
    00429 #define AST_FLAG_ZOMBIE    (1 << 4) /*!< if we are a zombie */
    00430 #define AST_FLAG_EXCEPTION (1 << 5) /*!< if there is a pending exception */
    00431 #define AST_FLAG_MOH    (1 << 6) /*!< XXX anthm promises me this will disappear XXX listening to moh */
    00432 #define AST_FLAG_SPYING    (1 << 7) /*!< XXX might also go away XXX is spying on someone */
    00433 #define AST_FLAG_NBRIDGE   (1 << 8) /*!< is it in a native bridge */
    00434 #define AST_FLAG_IN_AUTOLOOP  (1 << 9) /*!< the channel is in an auto-incrementing dialplan processor,
    00435                      so when ->priority is set, it will get incremented before
    00436                      finding the next priority to run
    00437                   */
    00438 #define AST_FLAG_NOTNEW    (1 << 10)   /*!< see bug:7855 incorrect Newchannel event generation */
    00439 /* @} */
    00440
    00441 #define AST_FEATURE_PLAY_WARNING (1 << 0)
    00442 #define AST_FEATURE_REDIRECT     (1 << 1)
    00443 #define AST_FEATURE_DISCONNECT      (1 << 2)
    00444 #define AST_FEATURE_ATXFER    (1 << 3)
    00445 #define AST_FEATURE_AUTOMON      (1 << 4)
    00446
    00447 #define AST_FEATURE_FLAG_NEEDSDTMF  (1 << 0)
    00448 #define AST_FEATURE_FLAG_CALLEE     (1 << 1)
    00449 #define AST_FEATURE_FLAG_CALLER     (1 << 2)
    00450
    00451 struct ast_bridge_config {
    00452    struct ast_flags features_caller;
    00453    struct ast_flags features_callee;
    00454    struct timeval start_time;
    00455    long feature_timer;
    00456    long timelimit;
    00457    long play_warning;
    00458    long warning_freq;
    00459    char *warning_sound;
    00460    char *end_sound;
    00461    char *start_sound;
    00462    int firstpass;
    00463    unsigned int flags;
    00464 };
    00465
    00466 struct chanmon;
    00467
    00468 #define LOAD_OH(oh) {   \
    00469    oh.context = context; \
    00470    oh.exten = exten; \
    00471    oh.priority = priority; \
    00472    oh.cid_num = cid_num; \
    00473    oh.cid_name = cid_name; \
    00474    oh.account = account; \
    00475    oh.vars = vars; \
    00476    oh.parent_channel = NULL; \
    00477 }
    00478
    00479 struct outgoing_helper {
    00480    const char *context;
    00481    const char *exten;
    00482    int priority;
    00483    const char *cid_num;
    00484    const char *cid_name;
    00485    const char *account;
    00486    struct ast_variable *vars;
    00487    struct ast_channel *parent_channel;
    00488 };
    00489
    00490 #define AST_CDR_TRANSFER   (1 << 0)
    00491 #define AST_CDR_FORWARD    (1 << 1)
    00492 #define AST_CDR_CALLWAIT   (1 << 2)
    00493 #define AST_CDR_CONFERENCE (1 << 3)
    00494
    00495 #define AST_ADSI_UNKNOWN   (0)
    00496 #define AST_ADSI_AVAILABLE (1)
    00497 #define AST_ADSI_UNAVAILABLE  (2)
    00498 #define AST_ADSI_OFFHOOKONLY  (3)
    00499
    00500 #define AST_SOFTHANGUP_DEV    (1 << 0) /*!< Soft hangup by device */
    00501 #define AST_SOFTHANGUP_ASYNCGOTO (1 << 1) /*!< Soft hangup for async goto */
    00502 #define AST_SOFTHANGUP_SHUTDOWN     (1 << 2)
    00503 #define AST_SOFTHANGUP_TIMEOUT      (1 << 3)
    00504 #define AST_SOFTHANGUP_APPUNLOAD (1 << 4)
    00505 #define AST_SOFTHANGUP_EXPLICIT     (1 << 5)
    00506 #define AST_SOFTHANGUP_UNBRIDGE     (1 << 6)
    00507
    00508
    00509 /*! \defgroup ChanState Channel states
    00510 \brief Bits 0-15 of state are reserved for the state (up/down) of the line */
    00511 /*! @{ */
    00512 /*! Channel is down and available */
    00513 #define AST_STATE_DOWN     0
    00514 /*! Channel is down, but reserved */
    00515 #define AST_STATE_RESERVED 1
    00516 /*! Channel is off hook */
    00517 #define AST_STATE_OFFHOOK  2
    00518 /*! Digits (or equivalent) have been dialed */
    00519 #define AST_STATE_DIALING  3
    00520 /*! Line is ringing */
    00521 #define AST_STATE_RING     4
    00522 /*! Remote end is ringing */
    00523 #define AST_STATE_RINGING  5
    00524 /*! Line is up */
    00525 #define AST_STATE_UP    6
    00526 /*! Line is busy */
    00527 #define AST_STATE_BUSY     7
    00528 /*! Digits (or equivalent) have been dialed while offhook */
    00529 #define AST_STATE_DIALING_OFFHOOK   8
    00530 /*! Channel has detected an incoming call and is waiting for ring */
    00531 #define AST_STATE_PRERING       9
    00532
    00533 /* Bits 16-32 of state are reserved for flags (See \ref ChanState ) */
    00534 /*! Do not transmit voice data */
    00535 #define AST_STATE_MUTE     (1 << 16)
    00536 /*! @} */
    00537
    00538 /*! \brief Change the state of a channel */
    00539 int ast_setstate(struct ast_channel *chan, int state);
    00540
    00541 /*! \brief Create a channel structure
    00542     \return Returns NULL on failure to allocate.
    00543    \note New channels are
    00544    by default set to the "default" context and
    00545    extension "s"
    00546  */
    00547 struct ast_channel *ast_channel_alloc(int needalertpipe);
    00548
    00549 /*! \brief Queue an outgoing frame */
    00550 int ast_queue_frame(struct ast_channel *chan, struct ast_frame *f);
    00551
    00552 /*! \brief Queue a hangup frame */
    00553 int ast_queue_hangup(struct ast_channel *chan);
    00554
    00555 /*! \brief Queue a control frame */
    00556 int ast_queue_control(struct ast_channel *chan, int control);
    00557
    00558
    00559 /*! \brief Change channel name */
    00560 void ast_change_name(struct ast_channel *chan, char *newname);
    00561
    00562 /*! \brief Free a channel structure */
    00563 void  ast_channel_free(struct ast_channel *);
    00564
    00565 /*! \brief Requests a channel
    00566  * \param type type of channel to request
    00567  * \param format requested channel format
    00568  * \param data data to pass to the channel requester
    00569  * \param status status
    00570  * Request a channel of a given type, with data as optional information used
    00571  * by the low level module
    00572  * \return Returns an ast_channel on success, NULL on failure.
    00573  */
    00574 struct ast_channel *ast_request(const char *type, int format, void *data, int *status);
    00575
    00576 /*!
    00577  * \brief Request a channel of a given type, with data as optional information used
    00578  * by the low level module and attempt to place a call on it
    00579  * \param type type of channel to request
    00580  * \param format requested channel format
    00581  * \param data data to pass to the channel requester
    00582  * \param timeout maximum amount of time to wait for an answer
    00583  * \param reason why unsuccessful (if unsuceessful)
    00584  * \param cidnum Caller-ID Number
    00585  * \param cidname Caller-ID Name
    00586  * \return Returns an ast_channel on success or no answer, NULL on failure.  Check the value of chan->_state
    00587  * to know if the call was answered or not.
    00588  */
    00589 struct ast_channel *ast_request_and_dial(const char *type, int format, void *data, int timeout, int *reason, const char *cidnum, const char *cidname);
    00590
    00591 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);
    00592
    00593 /*!\brief Register a channel technology (a new channel driver)
    00594  * Called by a channel module to register the kind of channels it supports.
    00595  * \param tech Structure defining channel technology or "type"
    00596  * \return Returns 0 on success, -1 on failure.
    00597  */
    00598 int ast_channel_register(const struct ast_channel_tech *tech);
    00599
    00600 /*! \brief Unregister a channel technology
    00601  * \param tech Structure defining channel technology or "type" that was previously registered
    00602  * \return No return value.
    00603  */
    00604 void ast_channel_unregister(const struct ast_channel_tech *tech);
    00605
    00606 /*! \brief Get a channel technology structure by name
    00607  * \param name name of technology to find
    00608  * \return a pointer to the structure, or NULL if no matching technology found
    00609  */
    00610 const struct ast_channel_tech *ast_get_channel_tech(const char *name);
    00611
    00612 /*! \brief Hang up a channel
    00613  * \note This function performs a hard hangup on a channel.  Unlike the soft-hangup, this function
    00614  * performs all stream stopping, etc, on the channel that needs to end.
    00615  * chan is no longer valid after this call.
    00616  * \param chan channel to hang up
    00617  * \return Returns 0 on success, -1 on failure.
    00618  */
    00619 int ast_hangup(struct ast_channel *chan);
    00620
    00621 /*! \brief Softly hangup up a channel
    00622  * \param chan channel to be soft-hung-up
    00623  * Call the protocol layer, but don't destroy the channel structure (use this if you are trying to
    00624  * safely hangup a channel managed by another thread.
    00625  * \param cause   Ast hangupcause for hangup
    00626  * \return Returns 0 regardless
    00627  */
    00628 int ast_softhangup(struct ast_channel *chan, int cause);
    00629
    00630 /*! \brief Softly hangup up a channel (no channel lock)
    00631  * \param chan channel to be soft-hung-up
    00632  * \param cause   Ast hangupcause for hangup (see cause.h) */
    00633 int ast_softhangup_nolock(struct ast_channel *chan, int cause);
    00634
    00635 /*! \brief Check to see if a channel is needing hang up
    00636  * \param chan channel on which to check for hang up
    00637  * This function determines if the channel is being requested to be hung up.
    00638  * \return Returns 0 if not, or 1 if hang up is requested (including time-out).
    00639  */
    00640 int ast_check_hangup(struct ast_channel *chan);
    00641
    00642 /*! \brief Compare a offset with the settings of when to hang a channel up
    00643  * \param chan channel on which to check for hang up
    00644  * \param offset offset in seconds from current time
    00645  * \return 1, 0, or -1
    00646  * This function compares a offset from current time with the absolute time
    00647  * out on a channel (when to hang up). If the absolute time out on a channel
    00648  * is earlier than current time plus the offset, it returns 1, if the two
    00649  * time values are equal, it return 0, otherwise, it retturn -1.
    00650  */
    00651 int ast_channel_cmpwhentohangup(struct ast_channel *chan, time_t offset);
    00652
    00653 /*! \brief Set when to hang a channel up
    00654  * \param chan channel on which to check for hang up
    00655  * \param offset offset in seconds from current time of when to hang up
    00656  * This function sets the absolute time out on a channel (when to hang up).
    00657  */
    00658 void ast_channel_setwhentohangup(struct ast_channel *chan, time_t offset);
    00659
    00660 /*! \brief Answer a ringing call
    00661  * \param chan channel to answer
    00662  * This function answers a channel and handles all necessary call
    00663  * setup functions.
    00664  * \return Returns 0 on success, -1 on failure
    00665  */
    00666 int ast_answer(struct ast_channel *chan);
    00667
    00668 /*! \brief Make a call
    00669  * \param chan which channel to make the call on
    00670  * \param addr destination of the call
    00671  * \param timeout time to wait on for connect
    00672  * Place a call, take no longer than timeout ms.
    00673    \return Returns -1 on failure, 0 on not enough time
    00674    (does not automatically stop ringing), and
    00675    the number of seconds the connect took otherwise.
    00676    */
    00677 int ast_call(struct ast_channel *chan, char *addr, int timeout);
    00678
    00679 /*! \brief Indicates condition of channel
    00680  * \note Indicate a condition such as AST_CONTROL_BUSY, AST_CONTROL_RINGING, or AST_CONTROL_CONGESTION on a channel
    00681  * \param chan channel to change the indication
    00682  * \param condition which condition to indicate on the channel
    00683  * \return Returns 0 on success, -1 on failure
    00684  */
    00685 int ast_indicate(struct ast_channel *chan, int condition);
    00686
    00687 /* Misc stuff ------------------------------------------------ */
    00688
    00689 /*! \brief Wait for input on a channel
    00690  * \param chan channel to wait on
    00691  * \param ms length of time to wait on the channel
    00692  * Wait for input on a channel for a given # of milliseconds (<0 for indefinite).
    00693   \return Returns < 0 on  failure, 0 if nothing ever arrived, and the # of ms remaining otherwise */
    00694 int ast_waitfor(struct ast_channel *chan, int ms);
    00695
    00696 /*! \brief Wait for a specied amount of time, looking for hangups
    00697  * \param chan channel to wait for
    00698  * \param ms length of time in milliseconds to sleep
    00699  * Waits for a specified amount of time, servicing the channel as required.
    00700  * \return returns -1 on hangup, otherwise 0.
    00701  */
    00702 int ast_safe_sleep(struct ast_channel *chan, int ms);
    00703
    00704 /*! \brief Wait for a specied amount of time, looking for hangups and a condition argument
    00705  * \param chan channel to wait for
    00706  * \param ms length of time in milliseconds to sleep
    00707  * \param cond a function pointer for testing continue condition
    00708  * \param data argument to be passed to the condition test function
    00709  * \return returns -1 on hangup, otherwise 0.
    00710  * Waits for a specified amount of time, servicing the channel as required. If cond
    00711  * returns 0, this function returns.
    00712  */
    00713 int ast_safe_sleep_conditional(struct ast_channel *chan, int ms, int (*cond)(void*), void *data );
    00714
    00715 /*! \brief Waits for activity on a group of channels
    00716  * \param chan an array of pointers to channels
    00717  * \param n number of channels that are to be waited upon
    00718  * \param fds an array of fds to wait upon
    00719  * \param nfds the number of fds to wait upon
    00720  * \param exception exception flag
    00721  * \param outfd fd that had activity on it
    00722  * \param ms how long the wait was
    00723  * Big momma function here.  Wait for activity on any of the n channels, or any of the nfds
    00724    file descriptors.
    00725    \return Returns the channel with activity, or NULL on error or if an FD
    00726    came first.  If the FD came first, it will be returned in outfd, otherwise, outfd
    00727    will be -1 */
    00728 struct ast_channel *ast_waitfor_nandfds(struct ast_channel **chan, int n, int *fds, int nfds, int *exception, int *outfd, int *ms);
    00729
    00730 /*! Waits for input on a group of channels */
    00731 /*! Wait for input on an array of channels for a given # of milliseconds. Return channel
    00732    with activity, or NULL if none has activity.  time "ms" is modified in-place, if applicable */
    00733 struct ast_channel *ast_waitfor_n(struct ast_channel **chan, int n, int *ms);
    00734
    00735 /*! Waits for input on an fd */
    00736 /*! This version works on fd's only.  Be careful with it. */
    00737 int ast_waitfor_n_fd(int *fds, int n, int *ms, int *exception);
    00738
    00739
    00740 /*! Reads a frame */
    00741 /*!
    00742  * \param chan channel to read a frame from
    00743  * Read a frame.  Returns a frame, or NULL on error.  If it returns NULL, you
    00744    best just stop reading frames and assume the channel has been
    00745    disconnected. */
    00746 struct ast_frame *ast_read(struct ast_channel *chan);
    00747
    00748 /*! Write a frame to a channel */
    00749 /*!
    00750  * \param chan destination channel of the frame
    00751  * \param frame frame that will be written
    00752  * This function writes the given frame to the indicated channel.
    00753  * It returns 0 on success, -1 on failure.
    00754  */
    00755 int ast_write(struct ast_channel *chan, struct ast_frame *frame);
    00756
    00757 /*! Write video frame to a channel */
    00758 /*!
    00759  * \param chan destination channel of the frame
    00760  * \param frame frame that will be written
    00761  * This function writes the given frame to the indicated channel.
    00762  * It returns 1 on success, 0 if not implemented, and -1 on failure.
    00763  */
    00764 int ast_write_video(struct ast_channel *chan, struct ast_frame *frame);
    00765
    00766 /* Send empty audio to prime a channel driver */
    00767 int ast_prod(struct ast_channel *chan);
    00768
    00769 /*! Sets read format on channel chan */
    00770 /*!
    00771  * \param chan channel to change
    00772  * \param format format to change to
    00773  * Set read format for channel to whichever component of "format" is best.
    00774  * Returns 0 on success, -1 on failure
    00775  */
    00776 int ast_set_read_format(struct ast_channel *chan, int format);
    00777
    00778 /*! Sets write format on channel chan */
    00779 /*!
    00780  * \param chan channel to change
    00781  * \param format new format for writing
    00782  * Set write format for channel to whichever compoent of "format" is best.
    00783  * Returns 0 on success, -1 on failure
    00784  */
    00785 int ast_set_write_format(struct ast_channel *chan, int format);
    00786
    00787 /*! Sends text to a channel */
    00788 /*!
    00789  * \param chan channel to act upon
    00790  * \param text string of text to send on the channel
    00791  * Write text to a display on a channel
    00792  * Returns 0 on success, -1 on failure
    00793  */
    00794 int ast_sendtext(struct ast_channel *chan, const char *text);
    00795
    00796 /*! Receives a text character from a channel */
    00797 /*!
    00798  * \param chan channel to act upon
    00799  * \param timeout timeout in milliseconds (0 for infinite wait)
    00800  * Read a char of text from a channel
    00801  * Returns 0 on success, -1 on failure
    00802  */
    00803 int ast_recvchar(struct ast_channel *chan, int timeout);
    00804
    00805 /*! Send a DTMF digit to a channel */
    00806 /*!
    00807  * \param chan channel to act upon
    00808  * \param digit the DTMF digit to send, encoded in ASCII
    00809  * Send a DTMF digit to a channel.
    00810  * Returns 0 on success, -1 on failure
    00811  */
    00812 int ast_senddigit(struct ast_channel *chan, char digit);
    00813
    00814 /*! Receives a text string from a channel */
    00815 /*!
    00816  * \param chan channel to act upon
    00817  * \param timeout timeout in milliseconds (0 for infinite wait)
    00818  * \return the received text, or NULL to signify failure.
    00819  * Read a string of text from a channel
    00820  */
    00821 char *ast_recvtext(struct ast_channel *chan, int timeout);
    00822
    00823 /*! Browse channels in use */
    00824 /*!
    00825  * \param prev where you want to start in the channel list
    00826  * Browse the channels currently in use
    00827  * Returns the next channel in the list, NULL on end.
    00828  * If it returns a channel, that channel *has been locked*!
    00829  */
    00830 struct ast_channel *ast_channel_walk_locked(const struct ast_channel *prev);
    00831
    00832 /*! Get channel by name (locks channel) */
    00833 struct ast_channel *ast_get_channel_by_name_locked(const char *chan);
    00834
    00835 /*! Get channel by name prefix (locks channel) */
    00836 struct ast_channel *ast_get_channel_by_name_prefix_locked(const char *name, const int namelen);
    00837
    00838 /*! Get channel by name prefix (locks channel) */
    00839 struct ast_channel *ast_walk_channel_by_name_prefix_locked(struct ast_channel *chan, const char *name, const int namelen);
    00840
    00841 /*--- ast_get_channel_by_exten_locked: Get channel by exten (and optionally context) and lock it */
    00842 struct ast_channel *ast_get_channel_by_exten_locked(const char *exten, const char *context);
    00843
    00844 /*! Waits for a digit */
    00845 /*!
    00846  * \param c channel to wait for a digit on
    00847  * \param ms how many milliseconds to wait
    00848  * Wait for a digit.  Returns <0 on error, 0 on no entry, and the digit on success. */
    00849 int ast_waitfordigit(struct ast_channel *c, int ms);
    00850
    00851 /* Same as above with audio fd for outputing read audio and ctrlfd to monitor for
    00852    reading. Returns 1 if ctrlfd becomes available */
    00853 int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int ctrlfd);
    00854
    00855 /*! Reads multiple digits */
    00856 /*!
    00857  * \param c channel to read from
    00858  * \param s string to read in to.  Must be at least the size of your length
    00859  * \param len how many digits to read (maximum)
    00860  * \param timeout how long to timeout between digits
    00861  * \param rtimeout timeout to wait on the first digit
    00862  * \param enders digits to end the string
    00863  * Read in a digit string "s", max length "len", maximum timeout between
    00864    digits "timeout" (-1 for none), terminated by anything in "enders".  Give them rtimeout
    00865    for the first digit.  Returns 0 on normal return, or 1 on a timeout.  In the case of
    00866    a timeout, any digits that were read before the timeout will still be available in s.
    00867    RETURNS 2 in full version when ctrlfd is available, NOT 1*/
    00868 int ast_readstring(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders);
    00869 int ast_readstring_full(struct ast_channel *c, char *s, int len, int timeout, int rtimeout, char *enders, int audiofd, int ctrlfd);
    00870
    00871 /*! Report DTMF on channel 0 */
    00872 #define AST_BRIDGE_DTMF_CHANNEL_0      (1 << 0)
    00873 /*! Report DTMF on channel 1 */
    00874 #define AST_BRIDGE_DTMF_CHANNEL_1      (1 << 1)
    00875 /*! Return all voice frames on channel 0 */
    00876 #define AST_BRIDGE_REC_CHANNEL_0    (1 << 2)
    00877 /*! Return all voice frames on channel 1 */
    00878 #define AST_BRIDGE_REC_CHANNEL_1    (1 << 3)
    00879 /*! Ignore all signal frames except NULL */
    00880 #define AST_BRIDGE_IGNORE_SIGS         (1 << 4)
    00881
    00882
    00883 /*! Makes two channel formats compatible */
    00884 /*!
    00885  * \param c0 first channel to make compatible
    00886  * \param c1 other channel to make compatible
    00887  * Set two channels to compatible formats -- call before ast_channel_bridge in general .  Returns 0 on success
    00888    and -1 if it could not be done */
    00889 int ast_channel_make_compatible(struct ast_channel *c0, struct ast_channel *c1);
    00890
    00891 /*! Bridge two channels together */
    00892 /*!
    00893  * \param c0 first channel to bridge
    00894  * \param c1 second channel to bridge
    00895  * \param config config for the channels
    00896  * \param fo destination frame(?)
    00897  * \param rc destination channel(?)
    00898  * Bridge two channels (c0 and c1) together.  If an important frame occurs, we return that frame in
    00899    *rf (remember, it could be NULL) and which channel (0 or 1) in rc */
    00900 /* int ast_channel_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc); */
    00901 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);
    00902
    00903 /*! Weird function made for call transfers */
    00904 /*!
    00905  * \param original channel to make a copy of
    00906  * \param clone copy of the original channel
    00907  * This is a very strange and freaky function used primarily for transfer.  Suppose that
    00908    "original" and "clone" are two channels in random situations.  This function takes
    00909    the guts out of "clone" and puts them into the "original" channel, then alerts the
    00910    channel driver of the change, asking it to fixup any private information (like the
    00911    p->owner pointer) that is affected by the change.  The physical layer of the original
    00912    channel is hung up.  */
    00913 int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clone);
    00914
    00915 /*! Gives the string form of a given cause code */
    00916 /*!
    00917  * \param state cause to get the description of
    00918  * Give a name to a cause code
    00919  * Returns the text form of the binary cause code given
    00920  */
    00921 const char *ast_cause2str(int state);
    00922
    00923 /*! Gives the string form of a given channel state */
    00924 /*!
    00925  * \param state state to get the name of
    00926  * Give a name to a state
    00927  * Returns the text form of the binary state given
    00928  */
    00929 char *ast_state2str(int state);
    00930
    00931 /*! Gives the string form of a given transfer capability */
    00932 /*!
    00933  * \param transfercapability transfercapabilty to get the name of
    00934  * Give a name to a transfercapbility
    00935  * See above
    00936  * Returns the text form of the binary transfer capbility
    00937  */
    00938 char *ast_transfercapability2str(int transfercapability);
    00939
    00940 /* Options: Some low-level drivers may implement "options" allowing fine tuning of the
    00941    low level channel.  See frame.h for options.  Note that many channel drivers may support
    00942    none or a subset of those features, and you should not count on this if you want your
    00943    asterisk application to be portable.  They're mainly useful for tweaking performance */
    00944
    00945 /*! Sets an option on a channel */
    00946 /*!
    00947  * \param channel channel to set options on
    00948  * \param option option to change
    00949  * \param data data specific to option
    00950  * \param datalen length of the data
    00951  * \param block blocking or not
    00952  * Set an option on a channel (see frame.h), optionally blocking awaiting the reply
    00953  * Returns 0 on success and -1 on failure
    00954  */
    00955 int ast_channel_setoption(struct ast_channel *channel, int option, void *data, int datalen, int block);
    00956
    00957 /*! Pick the best codec  */
    00958 /* Choose the best codec...  Uhhh...   Yah. */
    00959 extern int ast_best_codec(int fmts);
    00960
    00961
    00962 /*! Checks the value of an option */
    00963 /*!
    00964  * Query the value of an option, optionally blocking until a reply is received
    00965  * Works similarly to setoption except only reads the options.
    00966  */
    00967 struct ast_frame *ast_channel_queryoption(struct ast_channel *channel, int option, void *data, int *datalen, int block);
    00968
    00969 /*! Checks for HTML support on a channel */
    00970 /*! Returns 0 if channel does not support HTML or non-zero if it does */
    00971 int ast_channel_supports_html(struct ast_channel *channel);
    00972
    00973 /*! Sends HTML on given channel */
    00974 /*! Send HTML or URL on link.  Returns 0 on success or -1 on failure */
    00975 int ast_channel_sendhtml(struct ast_channel *channel, int subclass, const char *data, int datalen);
    00976
    00977 /*! Sends a URL on a given link */
    00978 /*! Send URL on link.  Returns 0 on success or -1 on failure */
    00979 int ast_channel_sendurl(struct ast_channel *channel, const char *url);
    00980
    00981 /*! Defers DTMF */
    00982 /*! Defer DTMF so that you only read things like hangups and audio.  Returns
    00983    non-zero if channel was already DTMF-deferred or 0 if channel is just now
    00984    being DTMF-deferred */
    00985 int ast_channel_defer_dtmf(struct ast_channel *chan);
    00986
    00987 /*! Undeos a defer */
    00988 /*! Undo defer.  ast_read will return any dtmf characters that were queued */
    00989 void ast_channel_undefer_dtmf(struct ast_channel *chan);
    00990
    00991 /*! Initiate system shutdown -- prevents new channels from being allocated.
    00992     If "hangup" is non-zero, all existing channels will receive soft
    00993      hangups */
    00994 void ast_begin_shutdown(int hangup);
    00995
    00996 /*! Cancels an existing shutdown and returns to normal operation */
    00997 void ast_cancel_shutdown(void);
    00998
    00999 /*! Returns number of active/allocated channels */
    01000 int ast_active_channels(void);
    01001
    01002 /*! Returns non-zero if Asterisk is being shut down */
    01003 int ast_shutting_down(void);
    01004
    01005 /*! Activate a given generator */
    01006 int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params);
    01007
    01008 /*! Deactive an active generator */
    01009 void ast_deactivate_generator(struct ast_channel *chan);
    01010
    01011 void ast_set_callerid(struct ast_channel *chan, const char *cidnum, const char *cidname, const char *ani);
    01012
    01013 /*! Start a tone going */
    01014 int ast_tonepair_start(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
    01015 /*! Stop a tone from playing */
    01016 void ast_tonepair_stop(struct ast_channel *chan);
    01017 /*! Play a tone pair for a given amount of time */
    01018 int ast_tonepair(struct ast_channel *chan, int freq1, int freq2, int duration, int vol);
    01019
    01020 /*! Automatically service a channel for us... */
    01021 int ast_autoservice_start(struct ast_channel *chan);
    01022
    01023 /*! Stop servicing a channel for us...  Returns -1 on error or if channel has been hungup */
    01024 int ast_autoservice_stop(struct ast_channel *chan);
    01025
    01026 /* If built with zaptel optimizations, force a scheduled expiration on the
    01027    timer fd, at which point we call the callback function / data */
    01028 int ast_settimeout(struct ast_channel *c, int samples, int (*func)(void *data), void *data);
    01029
    01030 /*!   \brief Transfer a channel (if supported).  Returns -1 on error, 0 if not supported
    01031    and 1 if supported and requested
    01032    \param chan current channel
    01033    \param dest destination extension for transfer
    01034 */
    01035 int ast_transfer(struct ast_channel *chan, char *dest);
    01036
    01037 /*!   \brief  Start masquerading a channel
    01038    XXX This is a seriously wacked out operation.  We're essentially putting the guts of
    01039            the clone channel into the original channel.  Start by killing off the original
    01040            channel's backend.   I'm not sure we're going to keep this function, because
    01041            while the features are nice, the cost is very high in terms of pure nastiness. XXX
    01042    \param chan    Channel to masquerade
    01043 */
    01044 int ast_do_masquerade(struct ast_channel *chan);
    01045
    01046 /*!   \brief Find bridged channel
    01047    \param chan Current channel
    01048 */
    01049 struct ast_channel *ast_bridged_channel(struct ast_channel *chan);
    01050
    01051 /*!
    01052   \brief Inherits channel variable from parent to child channel
    01053   \param parent Parent channel
    01054   \param child Child channel
    01055
    01056   Scans all channel variables in the parent channel, looking for those
    01057   that should be copied into the child channel.
    01058   Variables whose names begin with a single '_' are copied into the
    01059   child channel with the prefix removed.
    01060   Variables whose names begin with '__' are copied into the child
    01061   channel with their names unchanged.
    01062 */
    01063 void ast_channel_inherit_variables(const struct ast_channel *parent, struct ast_channel *child);
    01064
    01065 /*!
    01066   \brief adds a list of channel variables to a channel
    01067   \param chan the channel
    01068   \param vars a linked list of variables
    01069
    01070   Variable names can be for a regular channel variable or a dialplan function
    01071   that has the ability to be written to.
    01072 */
    01073 void ast_set_variables(struct ast_channel *chan, struct ast_variable *vars);
    01074
    01075 /*!
    01076   \brief An opaque 'object' structure use by silence generators on channels.
    01077  */
    01078 struct ast_silence_generator;
    01079
    01080 /*!
    01081   \brief Starts a silence generator on the given channel.
    01082   \param chan The channel to generate silence on
    01083   \return An ast_silence_generator pointer, or NULL if an error occurs
    01084
    01085   This function will cause SLINEAR silence to be generated on the supplied
    01086   channel until it is disabled; if the channel cannot be put into SLINEAR
    01087   mode then the function will fail.
    01088
    01089   The pointer returned by this function must be preserved and passed to
    01090   ast_channel_stop_silence_generator when you wish to stop the silence
    01091   generation.
    01092  */
    01093 struct ast_silence_generator *ast_channel_start_silence_generator(struct ast_channel *chan);
    01094
    01095 /*!
    01096   \brief Stops a previously-started silence generator on the given channel.
    01097   \param chan The channel to operate on
    01098   \param state The ast_silence_generator pointer return by a previous call to
    01099   ast_channel_start_silence_generator.
    01100   \return nothing
    01101
    01102   This function will stop the operating silence generator and return the channel
    01103   to its previous write format.
    01104  */
    01105 void ast_channel_stop_silence_generator(struct ast_channel *chan, struct ast_silence_generator *state);
    01106
    01107 /* Misc. functions below */
    01108
    01109 /* Helper function for migrating select to poll */
    01110 static inline int ast_fdisset(struct pollfd *pfds, int fd, int max, int *start)
    01111 {
    01112    int x;
    01113    for (x=start ? *start : 0;x<max;x++)
    01114       if (pfds[x].fd == fd) {
    01115          if (start) {
    01116             if (x==*start)
    01117                (*start)++;
    01118          }
    01119          return pfds[x].revents;
    01120       }
    01121    return 0;
    01122 }
    01123
    01124 #ifdef SOLARIS
    01125 static inline void timersub(struct timeval *tvend, struct timeval *tvstart, struct timeval *tvdiff)
    01126 {
    01127    tvdiff->tv_sec = tvend->tv_sec - tvstart->tv_sec;
    01128    tvdiff->tv_usec = tvend->tv_usec - tvstart->tv_usec;
    01129    if (tvdiff->tv_usec < 0) {
    01130       tvdiff->tv_sec --;
    01131       tvdiff->tv_usec += 1000000;
    01132    }
    01133
    01134 }
    01135 #endif
    01136
    01137 /*! \brief Waits for activity on a group of channels
    01138  * \param nfds the maximum number of file descriptors in the sets
    01139  * \param rfds file descriptors to check for read availability
    01140  * \param wfds file descriptors to check for write availability
    01141  * \param efds file descriptors to check for exceptions (OOB data)
    01142  * \param tvp timeout while waiting for events
    01143  * This is the same as a standard select(), except it guarantees the
    01144  * behaviour where the passed struct timeval is updated with how much
    01145  * time was not slept while waiting for the specified events
    01146  */
    01147 static inline int ast_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *tvp)
    01148 {
    01149 #ifdef __linux__
    01150    return select(nfds, rfds, wfds, efds, tvp);
    01151 #else
    01152    if (tvp) {
    01153       struct timeval tv, tvstart, tvend, tvlen;
    01154       int res;
    01155
    01156       tv = *tvp;
    01157       gettimeofday(&tvstart, NULL);
    01158       res = select(nfds, rfds, wfds, efds, tvp);
    01159       gettimeofday(&tvend, NULL);
    01160       timersub(&tvend, &tvstart, &tvlen);
    01161       timersub(&tv, &tvlen, tvp);
    01162       if (tvp->tv_sec < 0 || (tvp->tv_sec == 0 && tvp->tv_usec < 0)) {
    01163          tvp->tv_sec = 0;
    01164          tvp->tv_usec = 0;
    01165       }
    01166       return res;
    01167    }
    01168    else
    01169       return select(nfds, rfds, wfds, efds, NULL);
    01170 #endif
    01171 }
    01172
    01173 #if !defined(ast_strdupa) && defined(__GNUC__)
    01174 # define ast_strdupa(s)                         \
    01175   (__extension__                             \
    01176     ({                                       \
    01177       __const char *__old = (s);                \
    01178       size_t __len = strlen (__old) + 1;           \
    01179       char *__new = (char *) __builtin_alloca (__len);   \
    01180       (char *) memcpy (__new, __old, __len);       \
    01181     }))
    01182 #endif
    01183
    01184 #ifdef DO_CRASH
    01185 #define CRASH do { fprintf(stderr, "!! Forcing immediate crash a-la abort !!\n"); *((int *)0) = 0; } while(0)
    01186 #else
    01187 #define CRASH do { } while(0)
    01188 #endif
    01189
    01190 #define CHECK_BLOCKING(c) {    \
    01191                      if (ast_test_flag(c, AST_FLAG_BLOCKING)) {\
    01192                         ast_log(LOG_WARNING, "Thread %ld Blocking '%s', already blocked by thread %ld in procedure %s\n", (long) pthread_self(), (c)->name, (long) (c)->blocker, (c)->blockproc); \
    01193                         CRASH; \
    01194                      } else { \
    01195                         (c)->blocker = pthread_self(); \
    01196                         (c)->blockproc = __PRETTY_FUNCTION__; \
    01197                            ast_set_flag(c, AST_FLAG_BLOCKING); \
    01198                            } }
    01199
    01200 extern ast_group_t ast_get_group(char *s);
    01201 /* print call- and pickup groups into buffer */
    01202 extern char *ast_print_group(char *buf, int buflen, ast_group_t group);
    01203
    01204
    01205 #if defined(__cplusplus) || defined(c_plusplus)
    01206 }
    01207 #endif
    01208
    01209 #endif /* _ASTERISK_CHANNEL_H */