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Asterisk developer's documentation


channel.h

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

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