spandsp  3.0.0
t30.h
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1 /*
2  * SpanDSP - a series of DSP components for telephony
3  *
4  * t30.h - definitions for T.30 fax processing
5  *
6  * Written by Steve Underwood <steveu@coppice.org>
7  *
8  * Copyright (C) 2003 Steve Underwood
9  *
10  * All rights reserved.
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU Lesser General Public License version 2.1,
14  * as published by the Free Software Foundation.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19  * GNU Lesser General Public License for more details.
20  *
21  * You should have received a copy of the GNU Lesser General Public
22  * License along with this program; if not, write to the Free Software
23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24  */
25 
26 /*! \file */
27 
28 #if !defined(_SPANDSP_T30_H_)
29 #define _SPANDSP_T30_H_
30 
31 /*! \page t30_page T.30 FAX protocol handling
32 
33 \section t30_page_sec_1 What does it do?
34 The T.30 protocol is the core protocol used for FAX transmission. This module
35 implements most of its key features. It does not interface to the outside world.
36 Seperate modules do that for T.38, analogue line, and other forms of FAX
37 communication.
38 
39 Current features of this module include:
40 
41  - FAXing to and from multi-page TIFF/F files, whose images are one of the standard
42  FAX sizes.
43  - V.27ter, V.29 and V.17 modes (2400bps, to 14,400bps).
44  - T.4 1D (MH), T.4 2D,(MR) and T.6 (MMR) compression.
45  - Error correction mode (ECM).
46  - All standard horizonal resolutions (R8, R16, 300dpi, 600dpi, 800dpi, 1200dpi).
47  - All standard vertical resolutions (standard, fine, superfine, 300dpi, 600dpi, 800dpi, 1200dpi).
48  - All standard page widths (A4, B4, A3).
49  - All standard page lengths (A4, B4, North American letter, North American legal, continuous).
50  - Monitoring and sending identifier strings (CSI, TSI, and CIG).
51  - Monitoring and sending sub-address strings (SUB).
52  - Monitoring and sending polling sub-addresses (SEP).
53  - Monitoring and sending polled sub-addresses (PSA).
54  - Monitoring and sending sender identifications (SID).
55  - Monitoring and sending passwords (PWD).
56  - Monitoring of non-standard facility frames (NSF, NSC, and NSS).
57  - Sending custom non-standard facility frames (NSF, NSC, and NSS).
58  - Analogue modem and T.38 operation.
59 
60 \section t30_page_sec_2 How does it work?
61 
62 Some of the following is paraphrased from some notes found a while ago on the Internet.
63 I cannot remember exactly where they came from, but they are useful.
64 
65 \subsection t30_page_sec_2a The answer (CED) tone
66 
67 The T.30 standard says an answering fax device must send CED (a 2100Hz tone) for
68 approximately 3 seconds before sending the first handshake message. Some machines
69 send an 1100Hz or 1850Hz tone, and some send no tone at all. In fact, this answer
70 tone is so unpredictable, it cannot really be used. It should, however, always be
71 generated according to the specification.
72 
73 \subsection t30_page_sec_2b Common Timing Deviations
74 
75 The T.30 spec. specifies a number of time-outs. For example, after dialing a number,
76 a calling fax system should listen for a response for 35 seconds before giving up.
77 These time-out periods are as follows:
78 
79  - T1 - 35+-5s: the maximum time for which two fax system will attempt to identify each other
80  - T2 - 6+-1s: a time-out used to start the sequence for changing transmit parameters
81  - T3 - 10+-5s: a time-out used in handling operator interrupts
82  - T5 - 60+-5s: a time-out used in error correction mode
83 
84 These time-outs are sometimes misinterpreted. In addition, they are routinely
85 ignored, sometimes with good reason. For example, after placing a call, the
86 calling fax system is supposed to wait for 35 seconds before giving up. If the
87 answering unit does not answer on the first ring or if a voice answering machine
88 is connected to the line, or if there are many delays through the network,
89 the delay before answer can be much longer than 35 seconds.
90 
91 Fax units that support error correction mode (ECM) can respond to a post-image
92 handshake message with a receiver not ready (RNR) message. The calling unit then
93 queries the receiving fax unit with a receiver ready (RR) message. If the
94 answering unit is still busy (printing for example), it will repeat the RNR
95 message. According to the T.30 standard, this sequence (RR/RNR RR/RNR) can be
96 repeated for up to the end of T5 (60+-5s). However, many fax systems
97 ignore the time-out and will continue the sequence indefinitely, unless the user
98 manually overrides.
99 
100 All the time-outs are subject to alteration, and sometimes misuse. Good T.30
101 implementations must do the right thing, and tolerate others doing the wrong thing.
102 
103 \subsection t30_page_sec_2c Variations in the inter-carrier gap
104 
105 T.30 specifies 75+-20ms of silence between signals using different modulation
106 schemes. Examples are between the end of a DCS signal and the start of a TCF signal,
107 and between the end of an image and the start of a post-image signal. Many fax systems
108 violate this requirement, especially for the silent period between DCS and TCF.
109 This may be stretched to well over 100ms. If this period is too long, it can interfere with
110 handshake signal error recovery, should a packet be corrupted on the line. Systems
111 should ensure they stay within the prescribed T.30 limits, and be tolerant of others
112 being out of spec..
113 
114 \subsection t30_page_sec_2d Other timing variations
115 
116 Testing is required to determine the ability of a fax system to handle
117 variations in the duration of pauses between unacknowledged handshake message
118 repetitions, and also in the pauses between the receipt of a handshake command and
119 the start of a response to that command. In order to reduce the total
120 transmission time, many fax systems start sending a response message before the
121 end of the command has been received.
122 
123 \subsection t30_page_sec_2e Other deviations from the T.30 standard
124 
125 There are many other commonly encountered variations between machines, including:
126 
127  - frame sequence deviations
128  - preamble and flag sequence variations
129  - improper EOM usage
130  - unusual data rate fallback sequences
131  - common training pattern detection algorithms
132  - image transmission deviations
133  - use of the talker echo protect tone
134  - image padding and short lines
135  - RTP/RTN handshake message usage
136  - long duration lines
137  - nonstandard disconnect sequences
138  - DCN usage
139 */
140 
141 /*! The maximum length of a DIS, DTC or DCS frame */
142 #define T30_MAX_DIS_DTC_DCS_LEN 22
143 /*! The maximum length of the body of an ident string */
144 #define T30_MAX_IDENT_LEN 20
145 /*! The maximum length of the user string to insert in page headers */
146 #define T30_MAX_PAGE_HEADER_INFO 50
147 
148 typedef struct t30_state_s t30_state_t;
149 
150 /*!
151  T.30 phase B callback handler. This handler can be used to process addition
152  information available in some FAX calls, such as passwords. The callback handler
153  can access whatever additional information might have been received, using
154  t30_get_received_info().
155  \brief T.30 phase B callback handler.
156  \param user_data An opaque pointer.
157  \param result The phase B event code.
158  \return The new status. Normally, T30_ERR_OK is returned.
159 */
160 typedef int (*t30_phase_b_handler_t)(void *user_data, int result);
161 
162 /*!
163  T.30 phase D callback handler.
164  \brief T.30 phase D callback handler.
165  \param user_data An opaque pointer.
166  \param result The phase D event code.
167  \return The new status. Normally, T30_ERR_OK is returned.
168 */
169 typedef int (*t30_phase_d_handler_t)(void *user_data, int result);
170 
171 /*!
172  T.30 phase E callback handler.
173  \brief T.30 phase E callback handler.
174  \param user_data An opaque pointer.
175  \param completion_code The phase E completion code.
176 */
177 typedef void (*t30_phase_e_handler_t)(void *user_data, int completion_code);
178 
179 /*!
180  T.30 real time frame handler.
181  \brief T.30 real time frame handler.
182  \param user_data An opaque pointer.
183  \param incoming True for incoming, false for outgoing.
184  \param msg The HDLC message.
185  \param len The length of the message.
186 */
187 typedef void (*t30_real_time_frame_handler_t)(void *user_data,
188  bool direction,
189  const uint8_t msg[],
190  int len);
191 
192 /*!
193  T.30 document handler.
194  \brief T.30 document handler.
195  \param user_data An opaque pointer.
196  \param result The document event code.
197 */
198 typedef int (*t30_document_handler_t)(void *user_data, int status);
199 
200 /*!
201  T.30 set a receive or transmit type handler.
202  \brief T.30 set a receive or transmit type handler.
203  \param user_data An opaque pointer.
204  \param type The modem, tone or silence to be sent or received.
205  \param bit_rate The bit rate of the modem to be sent or received.
206  \param short_train True if the short training sequence should be used (where one exists).
207  \param use_hdlc False for bit stream, true for HDLC framing.
208 */
209 typedef void (*t30_set_handler_t)(void *user_data, int type, int bit_rate, int short_train, int use_hdlc);
210 
211 /*!
212  T.30 send HDLC handler.
213  \brief T.30 send HDLC handler.
214  \param user_data An opaque pointer.
215  \param msg The HDLC message.
216  \param len The length of the message. -1 to flush the HDLC queue.
217 */
218 typedef void (*t30_send_hdlc_handler_t)(void *user_data, const uint8_t msg[], int len);
219 
220 /*!
221  T.30 send document handler.
222  \brief T.30 send document handler.
223  \param user_data An opaque pointer.
224  \param msg The document chunk.
225  \param len The length of the chunk.
226  \return The actual length of the chunk.
227 */
228 typedef int (*t30_document_get_handler_t)(void *user_data, uint8_t msg[], int len);
229 
230 /*!
231  T.30 deliver document handler.
232  \brief T.30 deliver handler.
233  \param user_data An opaque pointer.
234  \param msg The document chunk.
235  \param len The length of the chunk.
236  \return The delivery status.
237 */
238 typedef int (*t30_document_put_handler_t)(void *user_data, const uint8_t msg[], int len);
239 
240 /*!
241  T.30 protocol completion codes, at phase E.
242 */
243 enum
244 {
245  T30_ERR_OK = 0, /*! OK */
246 
247  /* Link problems */
248  T30_ERR_CEDTONE, /*! The CED tone exceeded 5s */
249  T30_ERR_T0_EXPIRED, /*! Timed out waiting for initial communication */
250  T30_ERR_T1_EXPIRED, /*! Timed out waiting for the first message */
251  T30_ERR_T3_EXPIRED, /*! Timed out waiting for procedural interrupt */
252  T30_ERR_HDLC_CARRIER, /*! The HDLC carrier did not stop in a timely manner */
253  T30_ERR_CANNOT_TRAIN, /*! Failed to train with any of the compatible modems */
254  T30_ERR_OPER_INT_FAIL, /*! Operator intervention failed */
255  T30_ERR_INCOMPATIBLE, /*! Far end is not compatible */
256  T30_ERR_RX_INCAPABLE, /*! Far end is not able to receive */
257  T30_ERR_TX_INCAPABLE, /*! Far end is not able to transmit */
258  T30_ERR_NORESSUPPORT, /*! Far end cannot receive at the resolution of the image */
259  T30_ERR_NOSIZESUPPORT, /*! Far end cannot receive at the size of image */
260  T30_ERR_UNEXPECTED, /*! Unexpected message received */
261 
262  /* Phase E status values returned to a transmitter */
263  T30_ERR_TX_BADDCS, /*! Received bad response to DCS or training */
264  T30_ERR_TX_BADPG, /*! Received a DCN from remote after sending a page */
265  T30_ERR_TX_ECMPHD, /*! Invalid ECM response received from receiver */
266  T30_ERR_TX_GOTDCN, /*! Received a DCN while waiting for a DIS */
267  T30_ERR_TX_INVALRSP, /*! Invalid response after sending a page */
268  T30_ERR_TX_NODIS, /*! Received other than DIS while waiting for DIS */
269  T30_ERR_TX_PHBDEAD, /*! Received no response to DCS, training or TCF */
270  T30_ERR_TX_PHDDEAD, /*! No response after sending a page */
271  T30_ERR_TX_T5EXP, /*! Timed out waiting for receiver ready (ECM mode) */
272 
273  /* Phase E status values returned to a receiver */
274  T30_ERR_RX_ECMPHD, /*! Invalid ECM response received from transmitter */
275  T30_ERR_RX_GOTDCS, /*! DCS received while waiting for DTC */
276  T30_ERR_RX_INVALCMD, /*! Unexpected command after page received */
277  T30_ERR_RX_NOCARRIER, /*! Carrier lost during fax receive */
278  T30_ERR_RX_NOEOL, /*! Timed out while waiting for EOL (end of line) */
279  T30_ERR_RX_NOFAX, /*! Timed out while waiting for first line */
280  T30_ERR_RX_T2EXPDCN, /*! Timer T2 expired while waiting for DCN */
281  T30_ERR_RX_T2EXPD, /*! Timer T2 expired while waiting for phase D */
282  T30_ERR_RX_T2EXPFAX, /*! Timer T2 expired while waiting for fax page */
283  T30_ERR_RX_T2EXPMPS, /*! Timer T2 expired while waiting for next fax page */
284  T30_ERR_RX_T2EXPRR, /*! Timer T2 expired while waiting for RR command */
285  T30_ERR_RX_T2EXP, /*! Timer T2 expired while waiting for NSS, DCS or MCF */
286  T30_ERR_RX_DCNWHY, /*! Unexpected DCN while waiting for DCS or DIS */
287  T30_ERR_RX_DCNDATA, /*! Unexpected DCN while waiting for image data */
288  T30_ERR_RX_DCNFAX, /*! Unexpected DCN while waiting for EOM, EOP or MPS */
289  T30_ERR_RX_DCNPHD, /*! Unexpected DCN after EOM or MPS sequence */
290  T30_ERR_RX_DCNRRD, /*! Unexpected DCN after RR/RNR sequence */
291  T30_ERR_RX_DCNNORTN, /*! Unexpected DCN after requested retransmission */
292 
293  /* TIFF file problems */
294  T30_ERR_FILEERROR, /*! TIFF/F file cannot be opened */
295  T30_ERR_NOPAGE, /*! TIFF/F page not found */
296  T30_ERR_BADTIFF, /*! TIFF/F format is not compatible */
297  T30_ERR_BADPAGE, /*! TIFF/F page number tag missing */
298  T30_ERR_BADTAG, /*! Incorrect values for TIFF/F tags */
299  T30_ERR_BADTIFFHDR, /*! Bad TIFF/F header - incorrect values in fields */
300  T30_ERR_NOMEM, /*! Cannot allocate memory for more pages */
301 
302  /* General problems */
303  T30_ERR_RETRYDCN, /*! Disconnected after permitted retries */
304  T30_ERR_CALLDROPPED, /*! The call dropped prematurely */
305 
306  /* Feature negotiation issues */
307  T30_ERR_NOPOLL, /*! Poll not accepted */
308  T30_ERR_IDENT_UNACCEPTABLE, /*! Far end's ident is not acceptable */
309  T30_ERR_SUB_UNACCEPTABLE, /*! Far end's sub-address is not acceptable */
310  T30_ERR_SEP_UNACCEPTABLE, /*! Far end's selective polling address is not acceptable */
311  T30_ERR_PSA_UNACCEPTABLE, /*! Far end's polled sub-address is not acceptable */
312  T30_ERR_SID_UNACCEPTABLE, /*! Far end's sender identification is not acceptable */
313  T30_ERR_PWD_UNACCEPTABLE, /*! Far end's password is not acceptable */
314  T30_ERR_TSA_UNACCEPTABLE, /*! Far end's transmitting subscriber internet address is not acceptable */
315  T30_ERR_IRA_UNACCEPTABLE, /*! Far end's internet routing address is not acceptable */
316  T30_ERR_CIA_UNACCEPTABLE, /*! Far end's calling subscriber internet address is not acceptable */
317  T30_ERR_ISP_UNACCEPTABLE, /*! Far end's internet selective polling address is not acceptable */
318  T30_ERR_CSA_UNACCEPTABLE /*! Far end's called subscriber internet address is not acceptable */
319 };
320 
321 /*!
322  I/O modes for the T.30 protocol.
323  These are allocated such that the lower 4 bits represents the variant of the modem - e.g. the
324  particular bit rate selected.
325 */
326 enum
327 {
328  T30_MODEM_NONE = 0,
329  T30_MODEM_PAUSE,
330  T30_MODEM_CED,
331  T30_MODEM_CNG,
332  T30_MODEM_V21,
333  T30_MODEM_V27TER,
334  T30_MODEM_V29,
335  T30_MODEM_V17,
336  T30_MODEM_V34HDX,
337  T30_MODEM_DONE
338 };
339 
340 enum
341 {
342  /*! Support the V.27ter modem (2400, and 4800bps) for image transfer. */
344  /*! Support the V.29 modem (9600, and 7200bps) for image transfer. */
346  /*! Support the V.17 modem (14400, 12000, 9600 and 7200bps) for image transfer. */
348  /*! Support the V.34 modem (up to 33,600bps) for image transfer. */
350  /*! Support the Internet aware FAX mode (no bit rate limit) for image transfer. */
352 };
353 
354 enum
355 {
356  T30_FRONT_END_SEND_STEP_COMPLETE = 0,
357  /*! The current receive has completed. This is only needed to report an
358  unexpected end of the receive operation, as might happen with T.38
359  dying. */
361  T30_FRONT_END_SIGNAL_PRESENT,
362  T30_FRONT_END_SIGNAL_ABSENT,
363  T30_FRONT_END_CED_PRESENT,
364  T30_FRONT_END_CNG_PRESENT
365 };
366 
367 enum
368 {
369  /*! Enable support of identification, through the SID and/or PWD frames. */
371  /*! Enable support of selective polling, through the SEP frame. */
373  /*! Enable support of polling sub-addressing, through the PSA frame. */
375  /*! Enable support of multiple selective polling, through repeated used of the SEP and PSA frames. */
377  /*! Enable support of sub-addressing, through the SUB frame. */
379  /*! Enable support of transmitting subscriber internet address, through the TSA frame. */
381  /*! Enable support of internet routing address, through the IRA frame. */
383  /*! Enable support of calling subscriber internet address, through the CIA frame. */
385  /*! Enable support of internet selective polling address, through the ISP frame. */
387  /*! Enable support of called subscriber internet address, through the CSA frame. */
389  /*! Enable support of the field not valid (FNV) frame. */
391  /*! Enable support of the command repeat (CRP) frame. */
393 };
394 
395 enum
396 {
397  T30_IAF_MODE_T37 = 0x01,
398  T30_IAF_MODE_T38 = 0x02,
399  T30_IAF_MODE_FLOW_CONTROL = 0x04,
400  /*! Continuous flow mode means data is sent as fast as possible, usually across
401  the Internet, where speed is not constrained by a PSTN modem. */
403  /*! No TCF means TCF is not exchanged. The end points must sort out usable speed
404  issues locally. */
406  /*! No fill bits means do not insert fill bits, even if the T.30 messages request
407  them. */
409  /*! No indicators means do not send indicator messages when using T.38. */
411  /*! Use relaxed timers for T.38. This is appropriate when using TCP/TPKT for T.38,
412  as there is no point in anything but a long backstop timeout in such a mode. */
414 };
415 
416 typedef struct
417 {
418  /*! \brief The identifier string (CSI, TSI, CIG). */
419  char ident[T30_MAX_IDENT_LEN + 1];
420  /*! \brief The sub-address string (SUB). */
421  char sub_address[T30_MAX_IDENT_LEN + 1];
422  /*! \brief The selective polling sub-address (SEP). */
423  char selective_polling_address[T30_MAX_IDENT_LEN + 1];
424  /*! \brief The polled sub-address (PSA). */
425  char polled_sub_address[T30_MAX_IDENT_LEN + 1];
426  /*! \brief The sender identification (SID). */
427  char sender_ident[T30_MAX_IDENT_LEN + 1];
428  /*! \brief The password (PWD). */
429  char password[T30_MAX_IDENT_LEN + 1];
430  /*! \brief Non-standard facilities (NSF). */
431  uint8_t *nsf;
432  size_t nsf_len;
433  /*! \brief Non-standard facilities command (NSC). */
434  uint8_t *nsc;
435  size_t nsc_len;
436  /*! \brief Non-standard facilities set-up (NSS). */
437  uint8_t *nss;
438  size_t nss_len;
439  /*! \brief Transmitting subscriber internet address (TSA). */
440  int tsa_type;
441  char *tsa;
442  size_t tsa_len;
443  /*! \brief Internet routing address (IRA). */
444  int ira_type;
445  char *ira;
446  size_t ira_len;
447  /*! \brief Calling subscriber internet address (CIA). */
448  int cia_type;
449  char *cia;
450  size_t cia_len;
451  /*! \brief Internet selective polling address (ISP). */
452  int isp_type;
453  char *isp;
454  size_t isp_len;
455  /*! \brief Called subscriber internet address (CSA). */
456  int csa_type;
457  char *csa;
458  size_t csa_len;
460 
461 typedef struct
462 {
463  /*! \brief The current bit rate for image transfer. */
464  int bit_rate;
465  /*! \brief True if error correcting mode is used. */
467  /*! \brief The number of pages sent so far. */
468  int pages_tx;
469  /*! \brief The number of pages received so far. */
470  int pages_rx;
471  /*! \brief The number of pages in the file (<0 if not known). */
473  /*! \brief The type of image of the most recent file page */
475  /*! \brief The horizontal column-to-column resolution of the most recent file page, in pixels per metre */
477  /*! \brief The vertical row-to-row resolution of the most recent file page, in pixels per metre */
479  /*! \brief The number of horizontal pixels in the most recent file page. */
481  /*! \brief The number of vertical pixels in the most recent file page. */
483  /*! \brief The type of image of the most recent exchanged page */
484  int type;
485  /*! \brief The horizontal column-to-column resolution of the most recent exchanged page, in pixels per metre */
487  /*! \brief The vertical row-to-row resolution of the most recent exchanged page, in pixels per metre */
489  /*! \brief The number of horizontal pixels in the most recent exchanged page. */
490  int width;
491  /*! \brief The number of vertical pixels in the most recent exchanged page. */
492  int length;
493  /*! \brief The size of the image, in bytes */
495  /*! \brief The type of compression used between the FAX machines */
497  /*! \brief The number of bad pixel rows in the most recent page. */
498  int bad_rows;
499  /*! \brief The largest number of bad pixel rows in a block in the most recent page. */
501  /*! \brief The number of HDLC frame retries, if error correcting mode is used. */
503  /*! \brief Current status. */
505  /*! \brief The number of RTP events in this call. */
507  /*! \brief The number of RTN events in this call. */
509 } t30_stats_t;
510 
511 #if defined(__cplusplus)
512 extern "C"
513 {
514 #endif
515 
516 /*! Initialise a T.30 context.
517  \brief Initialise a T.30 context.
518  \param s The T.30 context.
519  \param calling_party True if the context is for a calling party. False if the
520  context is for an answering party.
521  \param set_rx_type_handler
522  \param set_rx_type_user_data
523  \param set_tx_type_handler
524  \param set_tx_type_user_data
525  \param send_hdlc_handler
526  \param send_hdlc_user_data
527  \return A pointer to the context, or NULL if there was a problem. */
528 SPAN_DECLARE(t30_state_t *) t30_init(t30_state_t *s,
529  bool calling_party,
531  void *set_rx_type_user_data,
533  void *set_tx_type_user_data,
535  void *send_hdlc_user_data);
536 
537 /*! Release a T.30 context.
538  \brief Release a T.30 context.
539  \param s The T.30 context.
540  \return 0 for OK, else -1. */
541 SPAN_DECLARE(int) t30_release(t30_state_t *s);
542 
543 /*! Free a T.30 context.
544  \brief Free a T.30 context.
545  \param s The T.30 context.
546  \return 0 for OK, else -1. */
547 SPAN_DECLARE(int) t30_free(t30_state_t *s);
548 
549 /*! Restart a T.30 context.
550  \brief Restart a T.30 context.
551  \param s The T.30 context.
552  \param calling_party True if the context is for a calling party. False if the
553  context is for an answering party.
554  \return 0 for OK, else -1. */
555 SPAN_DECLARE(int) t30_restart(t30_state_t *s, bool calling_party);
556 
557 /*! Check if a T.30 call is still active. This may be used to regularly poll
558  if the job has finished.
559  \brief Check if a T.30 call is still active.
560  \param s The T.30 context.
561  \return True for call still active, or false for call completed. */
562 SPAN_DECLARE(int) t30_call_active(t30_state_t *s);
563 
564 /*! Cleanup a T.30 context if the call terminates.
565  \brief Cleanup a T.30 context if the call terminates.
566  \param s The T.30 context. */
567 SPAN_DECLARE(void) t30_terminate(t30_state_t *s);
568 
569 /*! Inform the T.30 engine of a status change in the front end (end of tx, rx signal change, etc.).
570  \brief Inform the T.30 engine of a status change in the front end (end of tx, rx signal change, etc.).
571  \param user_data The T.30 context.
572  \param status The type of status change which occured. */
573 SPAN_DECLARE(void) t30_front_end_status(void *user_data, int status);
574 
575 /*! Get a bit of received non-ECM image data.
576  \brief Get a bit of received non-ECM image data.
577  \param user_data An opaque pointer, which must point to the T.30 context.
578  \return The next bit to transmit. */
579 SPAN_DECLARE(int) t30_non_ecm_get_bit(void *user_data);
580 
581 /*! Get a chunk of received non-ECM image data.
582  \brief Get a bit of received non-ECM image data.
583  \param user_data An opaque pointer, which must point to the T.30 context.
584  \param buf The buffer to contain the data.
585  \param max_len The maximum length of the chunk.
586  \return The actual length of the chunk. */
587 SPAN_DECLARE(int) t30_non_ecm_get(void *user_data, uint8_t buf[], int max_len);
588 
589 /*! Process a bit of received non-ECM image data.
590  \brief Process a bit of received non-ECM image data
591  \param user_data An opaque pointer, which must point to the T.30 context.
592  \param bit The received bit. */
593 SPAN_DECLARE(void) t30_non_ecm_put_bit(void *user_data, int bit);
594 
595 /*! Process a chunk of received non-ECM image data.
596  \brief Process a chunk of received non-ECM image data
597  \param user_data An opaque pointer, which must point to the T.30 context.
598  \param buf The buffer containing the received data.
599  \param len The length of the data in buf. */
600 SPAN_DECLARE(void) t30_non_ecm_put(void *user_data, const uint8_t buf[], int len);
601 
602 /*! Process a received HDLC frame.
603  \brief Process a received HDLC frame.
604  \param user_data The T.30 context.
605  \param msg The HDLC message.
606  \param len The length of the message, in octets.
607  \param ok True if the frame was received without error. */
608 SPAN_DECLARE(void) t30_hdlc_accept(void *user_data, const uint8_t msg[], int len, int ok);
609 
610 /*! Report the passage of time to the T.30 engine.
611  \brief Report the passage of time to the T.30 engine.
612  \param s The T.30 context.
613  \param samples The time change in 1/8000th second steps. */
614 SPAN_DECLARE(void) t30_timer_update(t30_state_t *s, int samples);
615 
616 /*! Get the current transfer statistics for the file being sent or received.
617  \brief Get the current transfer statistics.
618  \param s The T.30 context.
619  \param t A pointer to a buffer for the statistics. */
620 SPAN_DECLARE(void) t30_get_transfer_statistics(t30_state_t *s, t30_stats_t *t);
621 
622 /*! Request a local interrupt of FAX exchange.
623  \brief Request a local interrupt of FAX exchange.
624  \param s The T.30 context.
625  \param state True to enable interrupt request, else false. */
626 SPAN_DECLARE(void) t30_local_interrupt_request(t30_state_t *s, int state);
627 
628 /*! Allow remote interrupts of FAX exchange.
629  \brief Allow remote interrupts of FAX exchange.
630  \param s The T.30 context.
631  \param state True to allow interruptd, else false. */
632 SPAN_DECLARE(void) t30_remote_interrupts_allowed(t30_state_t *s, int state);
633 
634 #if defined(__cplusplus)
635 }
636 #endif
637 
638 #endif
639 /*- End of file ------------------------------------------------------------*/
Definition: t30.h:287
Definition: t30.h:249
Definition: t30.h:270
Definition: t30.h:343
int rtn_events
The number of RTN events in this call.
Definition: t30.h:508
Definition: t30.h:315
int pages_rx
The number of pages received so far.
Definition: t30.h:470
Definition: t30.h:378
Definition: t30.h:351
Definition: t30.h:390
Definition: t30.h:256
t30_send_hdlc_handler_t send_hdlc_handler
The transmitted HDLC frame handler.
Definition: private/t30.h:141
int image_length
The number of vertical pixels in the most recent file page.
Definition: t30.h:482
void(* t30_phase_e_handler_t)(void *user_data, int completion_code)
T.30 phase E callback handler.
Definition: t30.h:177
Definition: t30.h:291
Definition: t30.h:253
Definition: t30.h:410
Definition: t30.h:312
#define T30_MAX_IDENT_LEN
Definition: t30.h:144
Definition: t30.h:296
void * send_hdlc_user_data
An opaque pointer passed to the transmitted HDLC frame handler.
Definition: private/t30.h:143
int cia_type
Calling subscriber internet address (CIA).
Definition: t30.h:448
int(* t30_phase_d_handler_t)(void *user_data, int result)
T.30 phase D callback handler.
Definition: t30.h:169
int image_size
The size of the image, in bytes.
Definition: t30.h:494
Definition: t30.h:392
int tsa_type
Transmitting subscriber internet address (TSA).
Definition: t30.h:440
Definition: private/t30.h:35
int(* t30_document_handler_t)(void *user_data, int status)
T.30 document handler.
Definition: t30.h:198
int bit_rate
The current bit rate for image transfer.
Definition: t30.h:464
void t30_non_ecm_put(void *user_data, const uint8_t buf[], int len)
Process a chunk of received non-ECM image data.
Definition: t30.c:6476
Definition: t30.h:370
Definition: t30.h:304
Definition: t30.h:402
Definition: t30.h:347
uint8_t * nsc
Non-standard facilities command (NSC).
Definition: t30.h:434
Definition: t30.h:299
int x_resolution
The horizontal column-to-column resolution of the most recent exchanged page, in pixels per metre...
Definition: t30.h:486
Definition: t30.h:314
Definition: t30.h:255
Definition: t30.h:258
int csa_type
Called subscriber internet address (CSA).
Definition: t30.h:456
int(* t30_document_put_handler_t)(void *user_data, const uint8_t msg[], int len)
T.30 deliver handler.
Definition: t30.h:238
int isp_type
Internet selective polling address (ISP).
Definition: t30.h:452
Definition: t30.h:276
void t30_front_end_status(void *user_data, int status)
Inform the T.30 engine of a status change in the front end (end of tx, rx signal change, etc.).
Definition: t30.c:6810
Definition: t30.h:254
t30_set_handler_t set_rx_type_handler
The handler for changes to the receive mode.
Definition: private/t30.h:132
Definition: t30.h:252
void t30_hdlc_accept(void *user_data, const uint8_t msg[], int len, int ok)
Process a received HDLC frame.
Definition: t30.h:311
Definition: t30.h:310
Definition: t30.h:279
bool short_train
True if the short training sequence should be used.
Definition: private/t30.h:182
int ira_type
Internet routing address (IRA).
Definition: t30.h:444
Definition: t30.h:265
Definition: t30.h:405
int image_type
The type of image of the most recent file page.
Definition: t30.h:474
Definition: t30.h:294
Definition: t30.h:313
Definition: t30.h:267
void t30_timer_update(t30_state_t *s, int samples)
Report the passage of time to the T.30 engine.
Definition: t30.c:7125
Definition: t30.h:408
int image_width
The number of horizontal pixels in the most recent file page.
Definition: t30.h:480
Definition: t30.h:286
Definition: t30.h:263
int t30_call_active(t30_state_t *s)
Check if a T.30 call is still active.
Definition: t30.c:7416
Definition: t30.h:317
Definition: t30.h:260
int t30_release(t30_state_t *s)
Release a T.30 context.
Definition: t30.c:7399
int longest_bad_row_run
The largest number of bad pixel rows in a block in the most recent page.
Definition: t30.h:500
Definition: t30.h:250
Definition: t30.h:251
Definition: t30.h:300
Definition: t30.h:316
void * set_rx_type_user_data
An opaque pointer passed to the handler for changes to the receive mode.
Definition: private/t30.h:134
Definition: t30.h:413
Definition: t30.h:266
int type
The type of image of the most recent exchanged page.
Definition: t30.h:484
int(* t30_phase_b_handler_t)(void *user_data, int result)
T.30 phase B callback handler.
Definition: t30.h:160
int compression
The type of compression used between the FAX machines.
Definition: t30.h:496
Definition: t30.h:281
Definition: t30.h:269
uint8_t * nsf
Non-standard facilities (NSF).
Definition: t30.h:431
Definition: t30.h:318
Definition: t30.h:307
int current_status
Current status.
Definition: t30.h:504
Definition: t30.h:280
void t30_remote_interrupts_allowed(t30_state_t *s, int state)
Allow remote interrupts of FAX exchange.
Definition: t30.c:7301
Definition: t30.h:277
int rtp_events
The number of RTP events in this call.
Definition: t30.h:506
Definition: t30.h:257
Definition: t30.h:295
int pages_in_file
The number of pages in the file (<0 if not known).
Definition: t30.h:472
int t30_restart(t30_state_t *s, bool calling_party)
Restart a T.30 context.
Definition: t30.c:7307
void * set_tx_type_user_data
An opaque pointer passed to the handler for changes to the transmit mode.
Definition: private/t30.h:138
Definition: t30.h:278
Definition: t30.h:284
Definition: t30.h:288
Definition: t30.h:345
int(* t30_document_get_handler_t)(void *user_data, uint8_t msg[], int len)
T.30 send document handler.
Definition: t30.h:228
Definition: t30.h:274
t30_state_t * t30_init(t30_state_t *s, bool calling_party, t30_set_handler_t set_rx_type_handler, void *set_rx_type_user_data, t30_set_handler_t set_tx_type_handler, void *set_tx_type_user_data, t30_send_hdlc_handler_t send_hdlc_handler, void *send_hdlc_user_data)
Initialise a T.30 context.
Definition: t30.c:7349
Definition: t30.h:268
void t30_get_transfer_statistics(t30_state_t *s, t30_stats_t *t)
Get the current transfer statistics.
Definition: t30.c:7240
void t30_local_interrupt_request(t30_state_t *s, int state)
Request a local interrupt of FAX exchange.
Definition: t30.c:7288
int t30_free(t30_state_t *s)
Free a T.30 context.
Definition: t30.c:7408
Definition: t30.h:282
Definition: t30.h:360
Definition: t30.h:298
Definition: t30.h:248
Definition: t30.h:271
Definition: t30.h:372
int t30_non_ecm_get_bit(void *user_data)
Get a bit of received non-ECM image data.
Definition: t30.c:6525
int length
The number of vertical pixels in the most recent exchanged page.
Definition: t30.h:492
void t30_terminate(t30_state_t *s)
Cleanup a T.30 context if the call terminates.
Definition: t30.c:7204
Definition: t30.h:308
void(* t30_send_hdlc_handler_t)(void *user_data, const uint8_t msg[], int len)
T.30 send HDLC handler.
Definition: t30.h:218
t30_set_handler_t set_tx_type_handler
The handler for changes to the transmit mode.
Definition: private/t30.h:136
int image_x_resolution
The horizontal column-to-column resolution of the most recent file page, in pixels per metre...
Definition: t30.h:476
Definition: t30.h:283
Definition: t30.h:285
Definition: t30.h:297
Definition: t30.h:290
int error_correcting_mode
True if error correcting mode is used.
Definition: t30.h:466
void t30_non_ecm_put_bit(void *user_data, int bit)
Process a bit of received non-ECM image data.
Definition: t30.c:6427
Definition: t30.h:259
Definition: t30.h:264
int error_correcting_mode_retries
The number of HDLC frame retries, if error correcting mode is used.
Definition: t30.h:502
void(* t30_set_handler_t)(void *user_data, int type, int bit_rate, int short_train, int use_hdlc)
T.30 set a receive or transmit type handler.
Definition: t30.h:209
int t30_non_ecm_get(void *user_data, uint8_t buf[], int max_len)
Get a bit of received non-ECM image data.
Definition: t30.c:6562
int width
The number of horizontal pixels in the most recent exchanged page.
Definition: t30.h:490
bool calling_party
True if behaving as the calling party.
Definition: private/t30.h:47
int y_resolution
The vertical row-to-row resolution of the most recent exchanged page, in pixels per metre...
Definition: t30.h:488
Definition: t30.h:275
Definition: t30.h:303
void(* t30_real_time_frame_handler_t)(void *user_data, bool direction, const uint8_t msg[], int len)
T.30 real time frame handler.
Definition: t30.h:187
Definition: t30.h:416
uint8_t * nss
Non-standard facilities set-up (NSS).
Definition: t30.h:437
Definition: t30.h:309
Definition: t30.h:461
int image_y_resolution
The vertical row-to-row resolution of the most recent file page, in pixels per metre.
Definition: t30.h:478
Definition: t30.h:289
int state
The current state of the T.30 state machine.
Definition: private/t30.h:164
Definition: t30.h:349
int bad_rows
The number of bad pixel rows in the most recent page.
Definition: t30.h:498
int pages_tx
The number of pages sent so far.
Definition: t30.h:468