This file is indexed.

/usr/include/libtelnet.h is in libtelnet-dev 0.21-4.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
/*!
 * \brief libtelnet - TELNET protocol handling library
 *
 * SUMMARY:
 *
 * libtelnet is a library for handling the TELNET protocol.  It includes
 * routines for parsing incoming data from a remote peer as well as formatting
 * data to send to the remote peer.
 *
 * libtelnet uses a callback-oriented API, allowing application-specific
 * handling of various events.  The callback system is also used for buffering
 * outgoing protocol data, allowing the application to maintain control over
 * the actual socket connection.
 *
 * Features supported include the full TELNET protocol, Q-method option
 * negotiation, ZMP, MCCP2, MSSP, and NEW-ENVIRON.
 *
 * CONFORMS TO:
 *
 * RFC854  - http://www.faqs.org/rfcs/rfc854.html
 * RFC855  - http://www.faqs.org/rfcs/rfc855.html
 * RFC1091 - http://www.faqs.org/rfcs/rfc1091.html
 * RFC1143 - http://www.faqs.org/rfcs/rfc1143.html
 * RFC1408 - http://www.faqs.org/rfcs/rfc1408.html
 * RFC1572 - http://www.faqs.org/rfcs/rfc1572.html
 *
 * LICENSE:
 *
 * The author or authors of this code dedicate any and all copyright interest
 * in this code to the public domain. We make this dedication for the benefit
 * of the public at large and to the detriment of our heirs and successors. We
 * intend this dedication to be an overt act of relinquishment in perpetuity of
 * all present and future rights to this code under copyright law. 
 *
 * \file libtelnet.h
 *
 * \version 0.21
 *
 * \author Sean Middleditch <sean@sourcemud.org>
 */

#if !defined(LIBTELNET_INCLUDE)
#define LIBTELNET_INCLUDE 1

/* standard C headers necessary for the libtelnet API */
#include <stdarg.h>

/* C++ support */
#if defined(__cplusplus)
extern "C" {
#endif

/* printf type checking feature in GCC and some other compilers */
#if __GNUC__
# define TELNET_GNU_PRINTF(f,a) __attribute__((format(printf, f, a))) /*!< internal helper */
# define TELNET_GNU_SENTINEL __attribute__((sentinel)) /*!< internal helper */
#else
# define TELNET_GNU_PRINTF(f,a) /*!< internal helper */
# define TELNET_GNU_SENTINEL /*!< internal helper */
#endif

/*! Telnet state tracker object type. */
typedef struct telnet_t telnet_t;

/*! Telnet event object type. */
typedef union telnet_event_t telnet_event_t;

/*! Telnet option table element type. */
typedef struct telnet_telopt_t telnet_telopt_t;

/*! \name Telnet commands */
/*@{*/
/*! Telnet commands and special values. */
#define TELNET_IAC 255
#define TELNET_DONT 254
#define TELNET_DO 253
#define TELNET_WONT 252
#define TELNET_WILL 251
#define TELNET_SB 250
#define TELNET_GA 249
#define TELNET_EL 248
#define TELNET_EC 247
#define TELNET_AYT 246
#define TELNET_AO 245
#define TELNET_IP 244
#define TELNET_BREAK 243
#define TELNET_DM 242
#define TELNET_NOP 241
#define TELNET_SE 240
#define TELNET_EOR 239
#define TELNET_ABORT 238
#define TELNET_SUSP 237
#define TELNET_EOF 236
/*@}*/

/*! \name Telnet option values. */
/*@{*/
/*! Telnet options. */
#define TELNET_TELOPT_BINARY 0
#define TELNET_TELOPT_ECHO 1
#define TELNET_TELOPT_RCP 2
#define TELNET_TELOPT_SGA 3
#define TELNET_TELOPT_NAMS 4
#define TELNET_TELOPT_STATUS 5
#define TELNET_TELOPT_TM 6
#define TELNET_TELOPT_RCTE 7
#define TELNET_TELOPT_NAOL 8
#define TELNET_TELOPT_NAOP 9
#define TELNET_TELOPT_NAOCRD 10
#define TELNET_TELOPT_NAOHTS 11
#define TELNET_TELOPT_NAOHTD 12
#define TELNET_TELOPT_NAOFFD 13
#define TELNET_TELOPT_NAOVTS 14
#define TELNET_TELOPT_NAOVTD 15
#define TELNET_TELOPT_NAOLFD 16
#define TELNET_TELOPT_XASCII 17
#define TELNET_TELOPT_LOGOUT 18
#define TELNET_TELOPT_BM 19
#define TELNET_TELOPT_DET 20
#define TELNET_TELOPT_SUPDUP 21
#define TELNET_TELOPT_SUPDUPOUTPUT 22
#define TELNET_TELOPT_SNDLOC 23
#define TELNET_TELOPT_TTYPE 24
#define TELNET_TELOPT_EOR 25
#define TELNET_TELOPT_TUID 26
#define TELNET_TELOPT_OUTMRK 27
#define TELNET_TELOPT_TTYLOC 28
#define TELNET_TELOPT_3270REGIME 29
#define TELNET_TELOPT_X3PAD 30
#define TELNET_TELOPT_NAWS 31
#define TELNET_TELOPT_TSPEED 32
#define TELNET_TELOPT_LFLOW 33
#define TELNET_TELOPT_LINEMODE 34
#define TELNET_TELOPT_XDISPLOC 35
#define TELNET_TELOPT_ENVIRON 36
#define TELNET_TELOPT_AUTHENTICATION 37
#define TELNET_TELOPT_ENCRYPT 38
#define TELNET_TELOPT_NEW_ENVIRON 39
#define TELNET_TELOPT_MSSP 70
#define TELNET_TELOPT_COMPRESS2 86
#define TELNET_TELOPT_ZMP 93
#define TELNET_TELOPT_EXOPL 255

#define TELNET_TELOPT_MCCP2 86
/*@}*/

/*! \name Protocol codes for TERMINAL-TYPE commands. */
/*@{*/
/*! TERMINAL-TYPE codes. */
#define TELNET_TTYPE_IS 0
#define TELNET_TTYPE_SEND 1
/*@}*/

/*! \name Protocol codes for NEW-ENVIRON/ENVIRON commands. */
/*@{*/
/*! NEW-ENVIRON/ENVIRON codes. */
#define TELNET_ENVIRON_IS 0
#define TELNET_ENVIRON_SEND 1
#define TELNET_ENVIRON_INFO 2
#define TELNET_ENVIRON_VAR 0
#define TELNET_ENVIRON_VALUE 1
#define TELNET_ENVIRON_ESC 2
#define TELNET_ENVIRON_USERVAR 3
/*@}*/

/*! \name Protocol codes for MSSP commands. */
/*@{*/
/*! MSSP codes. */
#define TELNET_MSSP_VAR 1
#define TELNET_MSSP_VAL 2
/*@}*/

/*! \name Telnet state tracker flags. */
/*@{*/
/*! Control behavior of telnet state tracker. */
#define TELNET_FLAG_PROXY (1<<0)

#define TELNET_PFLAG_DEFLATE (1<<7)
/*@}*/

/*! 
 * error codes 
 */
enum telnet_error_t {
	TELNET_EOK = 0,   /*!< no error */
	TELNET_EBADVAL,   /*!< invalid parameter, or API misuse */
	TELNET_ENOMEM,    /*!< memory allocation failure */
	TELNET_EOVERFLOW, /*!< data exceeds buffer size */
	TELNET_EPROTOCOL, /*!< invalid sequence of special bytes */
	TELNET_ECOMPRESS  /*!< error handling compressed streams */
};
typedef enum telnet_error_t telnet_error_t; /*!< Error code type. */

/*! 
 * event codes 
 */
enum telnet_event_type_t {
	TELNET_EV_DATA = 0,        /*!< raw text data has been received */
	TELNET_EV_SEND,            /*!< data needs to be sent to the peer */
	TELNET_EV_IAC,             /*!< generic IAC code received */
	TELNET_EV_WILL,            /*!< WILL option negotiation received */
	TELNET_EV_WONT,            /*!< WONT option neogitation received */
	TELNET_EV_DO,              /*!< DO option negotiation received */
	TELNET_EV_DONT,            /*!< DONT option negotiation received */
	TELNET_EV_SUBNEGOTIATION,  /*!< sub-negotiation data received */
	TELNET_EV_COMPRESS,        /*!< compression has been enabled */
	TELNET_EV_ZMP,             /*!< ZMP command has been received */
	TELNET_EV_TTYPE,           /*!< TTYPE command has been received */
	TELNET_EV_ENVIRON,         /*!< ENVIRON command has been received */
	TELNET_EV_MSSP,            /*!< MSSP command has been received */
	TELNET_EV_WARNING,         /*!< recoverable error has occured */
	TELNET_EV_ERROR            /*!< non-recoverable error has occured */
};
typedef enum telnet_event_type_t telnet_event_type_t; /*!< Telnet event type. */

/*! 
 * environ/MSSP command information 
 */
struct telnet_environ_t {
	unsigned char type; /*!< either TELNET_ENVIRON_VAR or TELNET_ENVIRON_USERVAR */
	char *var;          /*!< name of the variable being set */
	char *value;        /*!< value of variable being set; empty string if no value */
};

/*! 
 * event information 
 */
union telnet_event_t {
	/*! 
	 * \brief Event type
	 *
	 * The type field will determine which of the other event structure fields
	 * have been filled in.  For instance, if the event type is TELNET_EV_ZMP,
	 * then the zmp event field (and ONLY the zmp event field) will be filled
	 * in.
	 */ 
	enum telnet_event_type_t type;

	/*! 
	 * data event: for DATA and SEND events 
	 */
	struct data_t {
		enum telnet_event_type_t _type; /*!< alias for type */
		const char *buffer;             /*!< byte buffer */
		size_t size;                    /*!< number of bytes in buffer */
	} data;

	/*! 
	 * WARNING and ERROR events 
	 */
	struct error_t {
		enum telnet_event_type_t _type; /*!< alias for type */
		const char *file;               /*!< file the error occured in */
		const char *func;               /*!< function the error occured in */
		const char *msg;                /*!< error message string */
		int line;                       /*!< line of file error occured on */
		telnet_error_t errcode;         /*!< error code */
	} error;

	/*! 
	 * command event: for IAC 
	 */
	struct iac_t {
		enum telnet_event_type_t _type; /*!< alias for type */
		unsigned char cmd;              /*!< telnet command received */
	} iac;

	/*! 
	 * negotiation event: WILL, WONT, DO, DONT 
	 */
	struct negotiate_t {
		enum telnet_event_type_t _type; /*!< alias for type */
		unsigned char telopt;           /*!< option being negotiated */
	} neg;

	/*! 
	 * subnegotiation event 
	 */
	struct subnegotiate_t {
		enum telnet_event_type_t _type; /*!< alias for type */
		const char *buffer;             /*!< data of sub-negotiation */
		size_t size;                    /*!< number of bytes in buffer */
		unsigned char telopt;           /*!< option code for negotiation */
	} sub;

	/*! 
	 * ZMP event 
	 */
	struct zmp_t {
		enum telnet_event_type_t _type; /*!< alias for type */
		const char **argv;              /*!< array of argument string */
		size_t argc;                    /*!< number of elements in argv */
	} zmp;

	/*! 
	 * TTYPE event 
	 */
	struct ttype_t {
		enum telnet_event_type_t _type; /*!< alias for type */
		unsigned char cmd;              /*!< TELNET_TTYPE_IS or TELNET_TTYPE_SEND */
		const char* name;               /*!< terminal type name (IS only) */
	} ttype;

	/*! 
	 * COMPRESS event 
	 */
	struct compress_t {
		enum telnet_event_type_t _type; /*!< alias for type */
		unsigned char state;            /*!< 1 if compression is enabled,
	                                         0 if disabled */
	} compress;

	/*! 
	 * ENVIRON/NEW-ENVIRON event
	 */
	struct environ_t {
		enum telnet_event_type_t _type;        /*!< alias for type */
		const struct telnet_environ_t *values; /*!< array of variable values */
		size_t size;                           /*!< number of elements in values */
		unsigned char cmd;                     /*!< SEND, IS, or INFO */
	} environ;
	
	/*!
	 * MSSP event
	 */
	struct mssp_t {
		enum telnet_event_type_t _type;        /*!< alias for type */
		const struct telnet_environ_t *values; /*!< array of variable values */
		size_t size;                           /*!< number of elements in values */
	} mssp;
};

/*! 
 * \brief event handler
 *
 * This is the type of function that must be passed to
 * telnet_init() when creating a new telnet object.  The
 * function will be invoked once for every event generated
 * by the libtelnet protocol parser.
 *
 * \param telnet    The telnet object that generated the event
 * \param event     Event structure with details about the event
 * \param user_data User-supplied pointer
 */
typedef void (*telnet_event_handler_t)(telnet_t *telnet,
		telnet_event_t *event, void *user_data);

/*! 
 * telopt support table element; use telopt of -1 for end marker 
 */
struct telnet_telopt_t {
	short telopt;      /*!< one of the TELOPT codes or -1 */
	unsigned char us;  /*!< TELNET_WILL or TELNET_WONT */
	unsigned char him; /*!< TELNET_DO or TELNET_DONT */
};

/*! 
 * state tracker -- private data structure 
 */
struct telnet_t;

/*!
 * \brief Initialize a telnet state tracker.
 *
 * This function initializes a new state tracker, which is used for all
 * other libtelnet functions.  Each connection must have its own
 * telnet state tracker object.
 *
 * \param telopts   Table of TELNET options the application supports.
 * \param eh        Event handler function called for every event.
 * \param flags     0 or TELNET_FLAG_PROXY.
 * \param user_data Optional data pointer that will be passsed to eh.
 * \return Telent state tracker object.
 */
extern telnet_t* telnet_init(const telnet_telopt_t *telopts,
		telnet_event_handler_t eh, unsigned char flags, void *user_data);

/*!
 * \brief Free up any memory allocated by a state tracker.
 *
 * This function must be called when a telnet state tracker is no
 * longer needed (such as after the connection has been closed) to
 * release any memory resources used by the state tracker.
 *
 * \param telnet Telnet state tracker object.
 */
extern void telnet_free(telnet_t *telnet);

/*!
 * \brief Push a byte buffer into the state tracker.
 *
 * Passes one or more bytes to the telnet state tracker for
 * protocol parsing.  The byte buffer is most often going to be
 * the buffer that recv() was called for while handling the
 * connection.
 *
 * \param telnet Telnet state tracker object.
 * \param buffer Pointer to byte buffer.
 * \param size   Number of bytes pointed to by buffer.
 */
extern void telnet_recv(telnet_t *telnet, const char *buffer,
		size_t size);

/*!
 * \brief Send a telnet command.
 *
 * \param telnet Telnet state tracker object.
 * \param cmd    Command to send.
 */
extern void telnet_iac(telnet_t *telnet, unsigned char cmd);

/*!
 * \brief Send negotiation command.
 *
 * Internally, libtelnet uses RFC1143 option negotiation rules.
 * The negotiation commands sent with this function may be ignored
 * if they are determined to be redundant.
 *
 * \param telnet Telnet state tracker object.
 * \param cmd    TELNET_WILL, TELNET_WONT, TELNET_DO, or TELNET_DONT.
 * \param opt    One of the TELNET_TELOPT_* values.
 */
extern void telnet_negotiate(telnet_t *telnet, unsigned char cmd,
		unsigned char opt);

/*!
 * Send non-command data (escapes IAC bytes).
 *
 * \param telnet Telnet state tracker object.
 * \param buffer Buffer of bytes to send.
 * \param size   Number of bytes to send.
 */
extern void telnet_send(telnet_t *telnet,
		const char *buffer, size_t size);

/*!
 * \brief Begin a sub-negotiation command.
 *
 * Sends IAC SB followed by the telopt code.  All following data sent
 * will be part of the sub-negotiation, until telnet_finish_sb() is
 * called.
 *
 * \param telnet Telnet state tracker object.
 * \param telopt One of the TELNET_TELOPT_* values.
 */
extern void telnet_begin_sb(telnet_t *telnet,
		unsigned char telopt);

/*!
 * \brief Finish a sub-negotiation command.
 *
 * This must be called after a call to telnet_begin_sb() to finish a
 * sub-negotiation command.
 *
 * \param telnet Telnet state tracker object.
 */
#define telnet_finish_sb(telnet) telnet_iac((telnet), TELNET_SE)

/*!
 * \brief Shortcut for sending a complete subnegotiation buffer.
 *
 * Equivalent to:
 *   telnet_begin_sb(telnet, telopt);
 *   telnet_send(telnet, buffer, size);
 *   telnet_finish_sb(telnet);
 *
 * \param telnet Telnet state tracker format.
 * \param telopt One of the TELNET_TELOPT_* values.
 * \param buffer Byte buffer for sub-negotiation data.
 * \param size   Number of bytes to use for sub-negotiation data.
 */
extern void telnet_subnegotiation(telnet_t *telnet, unsigned char telopt,
		const char *buffer, size_t size);

/*!
 * \brief Begin sending compressed data.
 *
 * This function will begein sending data using the COMPRESS2 option,
 * which enables the use of zlib to compress data sent to the client.
 * The client must offer support for COMPRESS2 with option negotiation,
 * and zlib support must be compiled into libtelnet.
 *
 * Only the server may call this command.
 *
 * \param telnet Telnet state tracker object.
 */
extern void telnet_begin_compress2(telnet_t *telnet);

/*!
 * \brief Send formatted data.
 *
 * This function is a wrapper around telnet_send().  It allows using
 * printf-style formatting.
 *
 * Additionally, this function will translate \\r to the CR NUL construct and
 * \\n with CR LF, as well as automatically escaping IAC bytes like
 * telnet_send().
 *
 * \param telnet Telnet state tracker object.
 * \param fmt    Format string.
 * \return Number of bytes sent.
 */
extern int telnet_printf(telnet_t *telnet, const char *fmt, ...)
		TELNET_GNU_PRINTF(2, 3);

/*!
 * \brief Send formatted data.
 *
 * See telnet_printf().
 */
extern int telnet_vprintf(telnet_t *telnet, const char *fmt, va_list va);

/*!
 * \brief Send formatted data (no newline escaping).
 *
 * This behaves identically to telnet_printf(), except that the \\r and \\n
 * characters are not translated.  The IAC byte is still escaped as normal
 * with telnet_send().
 *
 * \param telnet Telnet state tracker object.
 * \param fmt    Format string.
 * \return Number of bytes sent.
 */
extern int telnet_raw_printf(telnet_t *telnet, const char *fmt, ...)
		TELNET_GNU_PRINTF(2, 3);

/*!
 * \brief Send formatted data (no newline escaping).
 *
 * See telnet_raw_printf().
 */
extern int telnet_raw_vprintf(telnet_t *telnet, const char *fmt, va_list va);

/*!
 * \brief Begin a new set of NEW-ENVIRON values to request or send.
 *
 * This function will begin the sub-negotiation block for sending or
 * requesting NEW-ENVIRON values.
 *
 * The telnet_finish_newenviron() macro must be called after this
 * function to terminate the NEW-ENVIRON command.
 *
 * \param telnet Telnet state tracker object.
 * \param type   One of TELNET_ENVIRON_SEND, TELNET_ENVIRON_IS, or
 *               TELNET_ENVIRON_INFO.
 */
extern void telnet_begin_newenviron(telnet_t *telnet, unsigned char type);

/*!
 * \brief Send a NEW-ENVIRON variable name or value.
 *
 * This can only be called between calls to telnet_begin_newenviron() and
 * telnet_finish_newenviron().
 *
 * \param telnet Telnet state tracker object.
 * \param type   One of TELNET_ENVIRON_VAR, TELNET_ENVIRON_USERVAR, or
 *               TELNET_ENVIRON_VALUE.
 * \param string Variable name or value.
 */
extern void telnet_newenviron_value(telnet_t* telnet, unsigned char type,
		const char *string);

/*!
 * \brief Finish a NEW-ENVIRON command.
 *
 * This must be called after a call to telnet_begin_newenviron() to finish a
 * NEW-ENVIRON variable list.
 *
 * \param telnet Telnet state tracker object.
 */
#define telnet_finish_newenviron(telnet) telnet_finish_sb((telnet))

/*!
 * \brief Send the TERMINAL-TYPE SEND command.
 *
 * Sends the sequence IAC TERMINAL-TYPE SEND.
 *
 * \param telnet Telnet state tracker object.
 */
extern void telnet_ttype_send(telnet_t *telnet);

/*!
 * \brief Send the TERMINAL-TYPE IS command.
 *
 * Sends the sequence IAC TERMINAL-TYPE IS "string".
 *
 * According to the RFC, the recipient of a TERMINAL-TYPE SEND shall
 * send the next possible terminal-type the client supports.  Upon sending
 * the type, the client should switch modes to begin acting as the terminal
 * type is just sent.
 *
 * The server may continue sending TERMINAL-TYPE IS until it receives a
 * terminal type is understands.  To indicate to the server that it has
 * reached the end of the available optoins, the client must send the last
 * terminal type a second time.  When the server receives the same terminal
 * type twice in a row, it knows it has seen all available terminal types.
 *
 * After the last terminal type is sent, if the client receives another
 * TERMINAL-TYPE SEND command, it must begin enumerating the available
 * terminal types from the very beginning.  This allows the server to
 * scan the available types for a preferred terminal type and, if none
 * is found, to then ask the client to switch to an acceptable
 * alternative.
 *
 * Note that if the client only supports a single terminal type, then
 * simply sending that one type in response to every SEND will satisfy
 * the behavior requirements.
 *
 * \param telnet Telnet state tracker object.
 * \param ttype  Name of the terminal-type being sent.
 */
extern void telnet_ttype_is(telnet_t *telnet, const char* ttype);

/*!
 * \brief Send a ZMP command.
 *
 * \param telnet Telnet state tracker object.
 * \param argc   Number of ZMP commands being sent.
 * \param argv   Array of argument strings.
 */
extern void telnet_send_zmp(telnet_t *telnet, size_t argc, const char **argv);

/*!
 * \brief Send a ZMP command.
 *
 * Arguments are listed out in var-args style.  After the last argument, a
 * NULL pointer must be passed in as a sentinel value.
 *
 * \param telnet Telnet state tracker object.
 */
extern void telnet_send_zmpv(telnet_t *telnet, ...) TELNET_GNU_SENTINEL;

/*!
 * \brief Send a ZMP command.
 *
 * See telnet_send_zmpv().
 */
extern void telnet_send_vzmpv(telnet_t *telnet, va_list va);

/*!
 * \brief Begin sending a ZMP command
 *
 * \param telnet Telnet state tracker object.
 * \param cmd    The first argument (command name) for the ZMP command.
 */
extern void telnet_begin_zmp(telnet_t *telnet, const char *cmd);

/*!
 * \brief Send a ZMP command argument.
 *
 * \param telnet Telnet state tracker object.
 * \param arg    Telnet argument string.
 */
extern void telnet_zmp_arg(telnet_t *telnet, const char *arg);

/*!
 * \brief Finish a ZMP command.
 *
 * This must be called after a call to telnet_begin_zmp() to finish a
 * ZMP argument list.
 *
 * \param telnet Telnet state tracker object.
 */
#define telnet_finish_zmp(telnet) telnet_finish_sb((telnet))

/* C++ support */
#if defined(__cplusplus)
} /* extern "C" */
#endif

#endif /* !defined(LIBTELNET_INCLUDE) */