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More preparatory work: remove the <windows.h> include from lots of
[u/mdw/putty] / telnet.c
1 #include <stdio.h>
2 #include <stdlib.h>
3
4 #include "putty.h"
5
6 #ifndef FALSE
7 #define FALSE 0
8 #endif
9 #ifndef TRUE
10 #define TRUE 1
11 #endif
12
13 #define IAC 255 /* interpret as command: */
14 #define DONT 254 /* you are not to use option */
15 #define DO 253 /* please, you use option */
16 #define WONT 252 /* I won't use option */
17 #define WILL 251 /* I will use option */
18 #define SB 250 /* interpret as subnegotiation */
19 #define SE 240 /* end sub negotiation */
20
21 #define GA 249 /* you may reverse the line */
22 #define EL 248 /* erase the current line */
23 #define EC 247 /* erase the current character */
24 #define AYT 246 /* are you there */
25 #define AO 245 /* abort output--but let prog finish */
26 #define IP 244 /* interrupt process--permanently */
27 #define BREAK 243 /* break */
28 #define DM 242 /* data mark--for connect. cleaning */
29 #define NOP 241 /* nop */
30 #define EOR 239 /* end of record (transparent mode) */
31 #define ABORT 238 /* Abort process */
32 #define SUSP 237 /* Suspend process */
33 #define xEOF 236 /* End of file: EOF is already used... */
34
35 #define TELOPT_BINARY 0 /* 8-bit data path */
36 #define TELOPT_ECHO 1 /* echo */
37 #define TELOPT_RCP 2 /* prepare to reconnect */
38 #define TELOPT_SGA 3 /* suppress go ahead */
39 #define TELOPT_NAMS 4 /* approximate message size */
40 #define TELOPT_STATUS 5 /* give status */
41 #define TELOPT_TM 6 /* timing mark */
42 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */
43 #define TELOPT_NAOL 8 /* negotiate about output line width */
44 #define TELOPT_NAOP 9 /* negotiate about output page size */
45 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
46 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
47 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
48 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
49 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
50 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
51 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
52 #define TELOPT_XASCII 17 /* extended ascic character set */
53 #define TELOPT_LOGOUT 18 /* force logout */
54 #define TELOPT_BM 19 /* byte macro */
55 #define TELOPT_DET 20 /* data entry terminal */
56 #define TELOPT_SUPDUP 21 /* supdup protocol */
57 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
58 #define TELOPT_SNDLOC 23 /* send location */
59 #define TELOPT_TTYPE 24 /* terminal type */
60 #define TELOPT_EOR 25 /* end or record */
61 #define TELOPT_TUID 26 /* TACACS user identification */
62 #define TELOPT_OUTMRK 27 /* output marking */
63 #define TELOPT_TTYLOC 28 /* terminal location number */
64 #define TELOPT_3270REGIME 29 /* 3270 regime */
65 #define TELOPT_X3PAD 30 /* X.3 PAD */
66 #define TELOPT_NAWS 31 /* window size */
67 #define TELOPT_TSPEED 32 /* terminal speed */
68 #define TELOPT_LFLOW 33 /* remote flow control */
69 #define TELOPT_LINEMODE 34 /* Linemode option */
70 #define TELOPT_XDISPLOC 35 /* X Display Location */
71 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
72 #define TELOPT_AUTHENTICATION 37 /* Authenticate */
73 #define TELOPT_ENCRYPT 38 /* Encryption option */
74 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
75 #define TELOPT_EXOPL 255 /* extended-options-list */
76
77 #define TELQUAL_IS 0 /* option is... */
78 #define TELQUAL_SEND 1 /* send option */
79 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
80 #define BSD_VAR 1
81 #define BSD_VALUE 0
82 #define RFC_VAR 0
83 #define RFC_VALUE 1
84
85 #define CR 13
86 #define LF 10
87 #define NUL 0
88
89 #define iswritable(x) ( (x) != IAC && (x) != CR )
90
91 static char *telopt(int opt)
92 {
93 #define i(x) if (opt == TELOPT_ ## x) return #x;
94 i(BINARY);
95 i(ECHO);
96 i(RCP);
97 i(SGA);
98 i(NAMS);
99 i(STATUS);
100 i(TM);
101 i(RCTE);
102 i(NAOL);
103 i(NAOP);
104 i(NAOCRD);
105 i(NAOHTS);
106 i(NAOHTD);
107 i(NAOFFD);
108 i(NAOVTS);
109 i(NAOVTD);
110 i(NAOLFD);
111 i(XASCII);
112 i(LOGOUT);
113 i(BM);
114 i(DET);
115 i(SUPDUP);
116 i(SUPDUPOUTPUT);
117 i(SNDLOC);
118 i(TTYPE);
119 i(EOR);
120 i(TUID);
121 i(OUTMRK);
122 i(TTYLOC);
123 i(X3PAD);
124 i(NAWS);
125 i(TSPEED);
126 i(LFLOW);
127 i(LINEMODE);
128 i(XDISPLOC);
129 i(OLD_ENVIRON);
130 i(AUTHENTICATION);
131 i(ENCRYPT);
132 i(NEW_ENVIRON);
133 i(EXOPL);
134 #undef i
135 return "<unknown>";
136 }
137
138 static void telnet_size(void *handle, int width, int height);
139
140 struct Opt {
141 int send; /* what we initially send */
142 int nsend; /* -ve send if requested to stop it */
143 int ack, nak; /* +ve and -ve acknowledgements */
144 int option; /* the option code */
145 int index; /* index into telnet->opt_states[] */
146 enum {
147 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
148 } initial_state;
149 };
150
151 enum {
152 OPTINDEX_NAWS,
153 OPTINDEX_TSPEED,
154 OPTINDEX_TTYPE,
155 OPTINDEX_OENV,
156 OPTINDEX_NENV,
157 OPTINDEX_ECHO,
158 OPTINDEX_WE_SGA,
159 OPTINDEX_THEY_SGA,
160 NUM_OPTS
161 };
162
163 static const struct Opt o_naws =
164 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
165 static const struct Opt o_tspeed =
166 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
167 static const struct Opt o_ttype =
168 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
169 static const struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
170 OPTINDEX_OENV, INACTIVE
171 };
172 static const struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
173 OPTINDEX_NENV, REQUESTED
174 };
175 static const struct Opt o_echo =
176 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
177 static const struct Opt o_we_sga =
178 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
179 static const struct Opt o_they_sga =
180 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
181
182 static const struct Opt *const opts[] = {
183 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
184 &o_we_sga, &o_they_sga, NULL
185 };
186
187 typedef struct telnet_tag {
188 const struct plug_function_table *fn;
189 /* the above field _must_ be first in the structure */
190
191 Socket s;
192
193 void *frontend;
194 void *ldisc;
195 int term_width, term_height;
196
197 int opt_states[NUM_OPTS];
198
199 int echoing, editing;
200 int activated;
201 int bufsize;
202 int in_synch;
203 int sb_opt, sb_len;
204 char *sb_buf;
205 int sb_size;
206
207 enum {
208 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
209 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
210 } state;
211
212 } *Telnet;
213
214 #define TELNET_MAX_BACKLOG 4096
215
216 #define SB_DELTA 1024
217
218 static void c_write1(Telnet telnet, int c)
219 {
220 int backlog;
221 char cc = (char) c;
222 backlog = from_backend(telnet->frontend, 0, &cc, 1);
223 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
224 }
225
226 static void log_option(Telnet telnet, char *sender, int cmd, int option)
227 {
228 char buf[50];
229 sprintf(buf, "%s:\t%s %s", sender,
230 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
231 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
232 telopt(option));
233 logevent(telnet->frontend, buf);
234 }
235
236 static void send_opt(Telnet telnet, int cmd, int option)
237 {
238 unsigned char b[3];
239
240 b[0] = IAC;
241 b[1] = cmd;
242 b[2] = option;
243 telnet->bufsize = sk_write(telnet->s, b, 3);
244 log_option(telnet, "client", cmd, option);
245 }
246
247 static void deactivate_option(Telnet telnet, const struct Opt *o)
248 {
249 if (telnet->opt_states[o->index] == REQUESTED ||
250 telnet->opt_states[o->index] == ACTIVE)
251 send_opt(telnet, o->nsend, o->option);
252 telnet->opt_states[o->index] = REALLY_INACTIVE;
253 }
254
255 /*
256 * Generate side effects of enabling or disabling an option.
257 */
258 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
259 {
260 if (o->option == TELOPT_ECHO && o->send == DO)
261 telnet->echoing = !enabled;
262 else if (o->option == TELOPT_SGA && o->send == DO)
263 telnet->editing = !enabled;
264 if (telnet->ldisc) /* cause ldisc to notice the change */
265 ldisc_send(telnet->ldisc, NULL, 0, 0);
266
267 /* Ensure we get the minimum options */
268 if (!telnet->activated) {
269 if (telnet->opt_states[o_echo.index] == INACTIVE) {
270 telnet->opt_states[o_echo.index] = REQUESTED;
271 send_opt(telnet, o_echo.send, o_echo.option);
272 }
273 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
274 telnet->opt_states[o_we_sga.index] = REQUESTED;
275 send_opt(telnet, o_we_sga.send, o_we_sga.option);
276 }
277 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
278 telnet->opt_states[o_they_sga.index] = REQUESTED;
279 send_opt(telnet, o_they_sga.send, o_they_sga.option);
280 }
281 telnet->activated = TRUE;
282 }
283 }
284
285 static void activate_option(Telnet telnet, const struct Opt *o)
286 {
287 if (o->send == WILL && o->option == TELOPT_NAWS)
288 telnet_size(telnet, telnet->term_width, telnet->term_height);
289 if (o->send == WILL &&
290 (o->option == TELOPT_NEW_ENVIRON ||
291 o->option == TELOPT_OLD_ENVIRON)) {
292 /*
293 * We may only have one kind of ENVIRON going at a time.
294 * This is a hack, but who cares.
295 */
296 deactivate_option(telnet, o->option ==
297 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
298 }
299 option_side_effects(telnet, o, 1);
300 }
301
302 static void refused_option(Telnet telnet, const struct Opt *o)
303 {
304 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
305 telnet->opt_states[o_oenv.index] == INACTIVE) {
306 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
307 telnet->opt_states[o_oenv.index] = REQUESTED;
308 }
309 option_side_effects(telnet, o, 0);
310 }
311
312 static void proc_rec_opt(Telnet telnet, int cmd, int option)
313 {
314 const struct Opt *const *o;
315
316 log_option(telnet, "server", cmd, option);
317 for (o = opts; *o; o++) {
318 if ((*o)->option == option && (*o)->ack == cmd) {
319 switch (telnet->opt_states[(*o)->index]) {
320 case REQUESTED:
321 telnet->opt_states[(*o)->index] = ACTIVE;
322 activate_option(telnet, *o);
323 break;
324 case ACTIVE:
325 break;
326 case INACTIVE:
327 telnet->opt_states[(*o)->index] = ACTIVE;
328 send_opt(telnet, (*o)->send, option);
329 activate_option(telnet, *o);
330 break;
331 case REALLY_INACTIVE:
332 send_opt(telnet, (*o)->nsend, option);
333 break;
334 }
335 return;
336 } else if ((*o)->option == option && (*o)->nak == cmd) {
337 switch (telnet->opt_states[(*o)->index]) {
338 case REQUESTED:
339 telnet->opt_states[(*o)->index] = INACTIVE;
340 refused_option(telnet, *o);
341 break;
342 case ACTIVE:
343 telnet->opt_states[(*o)->index] = INACTIVE;
344 send_opt(telnet, (*o)->nsend, option);
345 option_side_effects(telnet, *o, 0);
346 break;
347 case INACTIVE:
348 case REALLY_INACTIVE:
349 break;
350 }
351 return;
352 }
353 }
354 /*
355 * If we reach here, the option was one we weren't prepared to
356 * cope with. So send a negative ack.
357 */
358 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
359 }
360
361 static void process_subneg(Telnet telnet)
362 {
363 unsigned char b[2048], *p, *q;
364 int var, value, n;
365 char *e;
366
367 switch (telnet->sb_opt) {
368 case TELOPT_TSPEED:
369 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
370 char logbuf[sizeof(cfg.termspeed) + 80];
371 b[0] = IAC;
372 b[1] = SB;
373 b[2] = TELOPT_TSPEED;
374 b[3] = TELQUAL_IS;
375 strcpy(b + 4, cfg.termspeed);
376 n = 4 + strlen(cfg.termspeed);
377 b[n] = IAC;
378 b[n + 1] = SE;
379 telnet->bufsize = sk_write(telnet->s, b, n + 2);
380 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
381 sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
382 logevent(telnet->frontend, logbuf);
383 } else
384 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
385 break;
386 case TELOPT_TTYPE:
387 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
388 char logbuf[sizeof(cfg.termtype) + 80];
389 b[0] = IAC;
390 b[1] = SB;
391 b[2] = TELOPT_TTYPE;
392 b[3] = TELQUAL_IS;
393 for (n = 0; cfg.termtype[n]; n++)
394 b[n + 4] = (cfg.termtype[n] >= 'a'
395 && cfg.termtype[n] <=
396 'z' ? cfg.termtype[n] + 'A' -
397 'a' : cfg.termtype[n]);
398 b[n + 4] = IAC;
399 b[n + 5] = SE;
400 telnet->bufsize = sk_write(telnet->s, b, n + 6);
401 b[n + 4] = 0;
402 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
403 sprintf(logbuf, "client:\tSB TTYPE IS %s", b + 4);
404 logevent(telnet->frontend, logbuf);
405 } else
406 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
407 break;
408 case TELOPT_OLD_ENVIRON:
409 case TELOPT_NEW_ENVIRON:
410 p = telnet->sb_buf;
411 q = p + telnet->sb_len;
412 if (p < q && *p == TELQUAL_SEND) {
413 char logbuf[50];
414 p++;
415 sprintf(logbuf, "server:\tSB %s SEND", telopt(telnet->sb_opt));
416 logevent(telnet->frontend, logbuf);
417 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
418 if (cfg.rfc_environ) {
419 value = RFC_VALUE;
420 var = RFC_VAR;
421 } else {
422 value = BSD_VALUE;
423 var = BSD_VAR;
424 }
425 /*
426 * Try to guess the sense of VAR and VALUE.
427 */
428 while (p < q) {
429 if (*p == RFC_VAR) {
430 value = RFC_VALUE;
431 var = RFC_VAR;
432 } else if (*p == BSD_VAR) {
433 value = BSD_VALUE;
434 var = BSD_VAR;
435 }
436 p++;
437 }
438 } else {
439 /*
440 * With NEW_ENVIRON, the sense of VAR and VALUE
441 * isn't in doubt.
442 */
443 value = RFC_VALUE;
444 var = RFC_VAR;
445 }
446 b[0] = IAC;
447 b[1] = SB;
448 b[2] = telnet->sb_opt;
449 b[3] = TELQUAL_IS;
450 n = 4;
451 e = cfg.environmt;
452 while (*e) {
453 b[n++] = var;
454 while (*e && *e != '\t')
455 b[n++] = *e++;
456 if (*e == '\t')
457 e++;
458 b[n++] = value;
459 while (*e)
460 b[n++] = *e++;
461 e++;
462 }
463 if (*cfg.username) {
464 b[n++] = var;
465 b[n++] = 'U';
466 b[n++] = 'S';
467 b[n++] = 'E';
468 b[n++] = 'R';
469 b[n++] = value;
470 e = cfg.username;
471 while (*e)
472 b[n++] = *e++;
473 }
474 b[n++] = IAC;
475 b[n++] = SE;
476 telnet->bufsize = sk_write(telnet->s, b, n);
477 sprintf(logbuf, "client:\tSB %s IS %s", telopt(telnet->sb_opt),
478 n == 6 ? "<nothing>" : "<stuff>");
479 logevent(telnet->frontend, logbuf);
480 }
481 break;
482 }
483 }
484
485 static void do_telnet_read(Telnet telnet, char *buf, int len)
486 {
487
488 while (len--) {
489 int c = (unsigned char) *buf++;
490
491 switch (telnet->state) {
492 case TOP_LEVEL:
493 case SEENCR:
494 if (c == NUL && telnet->state == SEENCR)
495 telnet->state = TOP_LEVEL;
496 else if (c == IAC)
497 telnet->state = SEENIAC;
498 else {
499 if (!telnet->in_synch)
500 c_write1(telnet, c);
501
502 #if 1
503 /* I can't get the F***ing winsock to insert the urgent IAC
504 * into the right position! Even with SO_OOBINLINE it gives
505 * it to recv too soon. And of course the DM byte (that
506 * arrives in the same packet!) appears several K later!!
507 *
508 * Oh well, we do get the DM in the right place so I'll
509 * just stop hiding on the next 0xf2 and hope for the best.
510 */
511 else if (c == DM)
512 telnet->in_synch = 0;
513 #endif
514 if (c == CR)
515 telnet->state = SEENCR;
516 else
517 telnet->state = TOP_LEVEL;
518 }
519 break;
520 case SEENIAC:
521 if (c == DO)
522 telnet->state = SEENDO;
523 else if (c == DONT)
524 telnet->state = SEENDONT;
525 else if (c == WILL)
526 telnet->state = SEENWILL;
527 else if (c == WONT)
528 telnet->state = SEENWONT;
529 else if (c == SB)
530 telnet->state = SEENSB;
531 else if (c == DM) {
532 telnet->in_synch = 0;
533 telnet->state = TOP_LEVEL;
534 } else {
535 /* ignore everything else; print it if it's IAC */
536 if (c == IAC) {
537 c_write1(telnet, c);
538 }
539 telnet->state = TOP_LEVEL;
540 }
541 break;
542 case SEENWILL:
543 proc_rec_opt(telnet, WILL, c);
544 telnet->state = TOP_LEVEL;
545 break;
546 case SEENWONT:
547 proc_rec_opt(telnet, WONT, c);
548 telnet->state = TOP_LEVEL;
549 break;
550 case SEENDO:
551 proc_rec_opt(telnet, DO, c);
552 telnet->state = TOP_LEVEL;
553 break;
554 case SEENDONT:
555 proc_rec_opt(telnet, DONT, c);
556 telnet->state = TOP_LEVEL;
557 break;
558 case SEENSB:
559 telnet->sb_opt = c;
560 telnet->sb_len = 0;
561 telnet->state = SUBNEGOT;
562 break;
563 case SUBNEGOT:
564 if (c == IAC)
565 telnet->state = SUBNEG_IAC;
566 else {
567 subneg_addchar:
568 if (telnet->sb_len >= telnet->sb_size) {
569 char *newbuf;
570 telnet->sb_size += SB_DELTA;
571 newbuf = (telnet->sb_buf ?
572 srealloc(telnet->sb_buf, telnet->sb_size) :
573 smalloc(telnet->sb_size));
574 if (newbuf)
575 telnet->sb_buf = newbuf;
576 else
577 telnet->sb_size -= SB_DELTA;
578 }
579 if (telnet->sb_len < telnet->sb_size)
580 telnet->sb_buf[telnet->sb_len++] = c;
581 telnet->state = SUBNEGOT; /* in case we came here by goto */
582 }
583 break;
584 case SUBNEG_IAC:
585 if (c != SE)
586 goto subneg_addchar; /* yes, it's a hack, I know, but... */
587 else {
588 process_subneg(telnet);
589 telnet->state = TOP_LEVEL;
590 }
591 break;
592 }
593 }
594 }
595
596 static int telnet_closing(Plug plug, char *error_msg, int error_code,
597 int calling_back)
598 {
599 Telnet telnet = (Telnet) plug;
600
601 if (telnet->s) {
602 sk_close(telnet->s);
603 telnet->s = NULL;
604 }
605 if (error_msg) {
606 /* A socket error has occurred. */
607 logevent(telnet->frontend, error_msg);
608 connection_fatal("%s", error_msg);
609 } /* Otherwise, the remote side closed the connection normally. */
610 return 0;
611 }
612
613 static int telnet_receive(Plug plug, int urgent, char *data, int len)
614 {
615 Telnet telnet = (Telnet) plug;
616 if (urgent)
617 telnet->in_synch = TRUE;
618 do_telnet_read(telnet, data, len);
619 return 1;
620 }
621
622 static void telnet_sent(Plug plug, int bufsize)
623 {
624 Telnet telnet = (Telnet) plug;
625 telnet->bufsize = bufsize;
626 }
627
628 /*
629 * Called to set up the Telnet connection.
630 *
631 * Returns an error message, or NULL on success.
632 *
633 * Also places the canonical host name into `realhost'. It must be
634 * freed by the caller.
635 */
636 static char *telnet_init(void *frontend_handle, void **backend_handle,
637 char *host, int port, char **realhost, int nodelay)
638 {
639 static const struct plug_function_table fn_table = {
640 telnet_closing,
641 telnet_receive,
642 telnet_sent
643 };
644 SockAddr addr;
645 char *err;
646 Telnet telnet;
647
648 telnet = smalloc(sizeof(*telnet));
649 telnet->fn = &fn_table;
650 telnet->s = NULL;
651 telnet->echoing = TRUE;
652 telnet->editing = TRUE;
653 telnet->activated = FALSE;
654 telnet->sb_buf = NULL;
655 telnet->sb_size = 0;
656 telnet->frontend = frontend_handle;
657 telnet->term_width = cfg.width;
658 telnet->term_height = cfg.height;
659 telnet->state = TOP_LEVEL;
660 *backend_handle = telnet;
661
662 /*
663 * Try to find host.
664 */
665 {
666 char buf[200];
667 sprintf(buf, "Looking up host \"%.170s\"", host);
668 logevent(telnet->frontend, buf);
669 }
670 addr = sk_namelookup(host, realhost);
671 if ((err = sk_addr_error(addr)))
672 return err;
673
674 if (port < 0)
675 port = 23; /* default telnet port */
676
677 /*
678 * Open socket.
679 */
680 {
681 char buf[200], addrbuf[100];
682 sk_getaddr(addr, addrbuf, 100);
683 sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
684 logevent(telnet->frontend, buf);
685 }
686 telnet->s = new_connection(addr, *realhost, port, 0, 1,
687 nodelay, (Plug) telnet);
688 if ((err = sk_socket_error(telnet->s)))
689 return err;
690
691 sk_addr_free(addr);
692
693 /*
694 * Initialise option states.
695 */
696 if (cfg.passive_telnet) {
697 const struct Opt *const *o;
698
699 for (o = opts; *o; o++)
700 telnet->opt_states[(*o)->index] = INACTIVE;
701 } else {
702 const struct Opt *const *o;
703
704 for (o = opts; *o; o++) {
705 telnet->opt_states[(*o)->index] = (*o)->initial_state;
706 if (telnet->opt_states[(*o)->index] == REQUESTED)
707 send_opt(telnet, (*o)->send, (*o)->option);
708 }
709 telnet->activated = TRUE;
710 }
711
712 /*
713 * Set up SYNCH state.
714 */
715 telnet->in_synch = FALSE;
716
717 return NULL;
718 }
719
720 /*
721 * Called to send data down the Telnet connection.
722 */
723 static int telnet_send(void *handle, char *buf, int len)
724 {
725 Telnet telnet = (Telnet) handle;
726 char *p;
727 static unsigned char iac[2] = { IAC, IAC };
728 static unsigned char cr[2] = { CR, NUL };
729 #if 0
730 static unsigned char nl[2] = { CR, LF };
731 #endif
732
733 if (telnet->s == NULL)
734 return 0;
735
736 p = buf;
737 while (p < buf + len) {
738 char *q = p;
739
740 while (iswritable((unsigned char) *p) && p < buf + len)
741 p++;
742 telnet->bufsize = sk_write(telnet->s, q, p - q);
743
744 while (p < buf + len && !iswritable((unsigned char) *p)) {
745 telnet->bufsize =
746 sk_write(telnet->s, (unsigned char) *p == IAC ? iac : cr, 2);
747 p++;
748 }
749 }
750
751 return telnet->bufsize;
752 }
753
754 /*
755 * Called to query the current socket sendability status.
756 */
757 static int telnet_sendbuffer(void *handle)
758 {
759 Telnet telnet = (Telnet) handle;
760 return telnet->bufsize;
761 }
762
763 /*
764 * Called to set the size of the window from Telnet's POV.
765 */
766 static void telnet_size(void *handle, int width, int height)
767 {
768 Telnet telnet = (Telnet) handle;
769 unsigned char b[16];
770 char logbuf[50];
771
772 telnet->term_width = width;
773 telnet->term_height = height;
774
775 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
776 return;
777 b[0] = IAC;
778 b[1] = SB;
779 b[2] = TELOPT_NAWS;
780 b[3] = telnet->term_width >> 8;
781 b[4] = telnet->term_width & 0xFF;
782 b[5] = telnet->term_height >> 8;
783 b[6] = telnet->term_height & 0xFF;
784 b[7] = IAC;
785 b[8] = SE;
786 telnet->bufsize = sk_write(telnet->s, b, 9);
787 sprintf(logbuf, "client:\tSB NAWS %d,%d",
788 ((unsigned char) b[3] << 8) + (unsigned char) b[4],
789 ((unsigned char) b[5] << 8) + (unsigned char) b[6]);
790 logevent(telnet->frontend, logbuf);
791 }
792
793 /*
794 * Send Telnet special codes.
795 */
796 static void telnet_special(void *handle, Telnet_Special code)
797 {
798 Telnet telnet = (Telnet) handle;
799 unsigned char b[2];
800
801 if (telnet->s == NULL)
802 return;
803
804 b[0] = IAC;
805 switch (code) {
806 case TS_AYT:
807 b[1] = AYT;
808 telnet->bufsize = sk_write(telnet->s, b, 2);
809 break;
810 case TS_BRK:
811 b[1] = BREAK;
812 telnet->bufsize = sk_write(telnet->s, b, 2);
813 break;
814 case TS_EC:
815 b[1] = EC;
816 telnet->bufsize = sk_write(telnet->s, b, 2);
817 break;
818 case TS_EL:
819 b[1] = EL;
820 telnet->bufsize = sk_write(telnet->s, b, 2);
821 break;
822 case TS_GA:
823 b[1] = GA;
824 telnet->bufsize = sk_write(telnet->s, b, 2);
825 break;
826 case TS_NOP:
827 b[1] = NOP;
828 telnet->bufsize = sk_write(telnet->s, b, 2);
829 break;
830 case TS_ABORT:
831 b[1] = ABORT;
832 telnet->bufsize = sk_write(telnet->s, b, 2);
833 break;
834 case TS_AO:
835 b[1] = AO;
836 telnet->bufsize = sk_write(telnet->s, b, 2);
837 break;
838 case TS_IP:
839 b[1] = IP;
840 telnet->bufsize = sk_write(telnet->s, b, 2);
841 break;
842 case TS_SUSP:
843 b[1] = SUSP;
844 telnet->bufsize = sk_write(telnet->s, b, 2);
845 break;
846 case TS_EOR:
847 b[1] = EOR;
848 telnet->bufsize = sk_write(telnet->s, b, 2);
849 break;
850 case TS_EOF:
851 b[1] = xEOF;
852 telnet->bufsize = sk_write(telnet->s, b, 2);
853 break;
854 case TS_EOL:
855 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
856 break;
857 case TS_SYNCH:
858 b[1] = DM;
859 telnet->bufsize = sk_write(telnet->s, b, 1);
860 telnet->bufsize = sk_write_oob(telnet->s, b + 1, 1);
861 break;
862 case TS_RECHO:
863 if (telnet->opt_states[o_echo.index] == INACTIVE ||
864 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
865 telnet->opt_states[o_echo.index] = REQUESTED;
866 send_opt(telnet, o_echo.send, o_echo.option);
867 }
868 break;
869 case TS_LECHO:
870 if (telnet->opt_states[o_echo.index] == ACTIVE) {
871 telnet->opt_states[o_echo.index] = REQUESTED;
872 send_opt(telnet, o_echo.nsend, o_echo.option);
873 }
874 break;
875 case TS_PING:
876 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
877 b[1] = NOP;
878 telnet->bufsize = sk_write(telnet->s, b, 2);
879 }
880 break;
881 }
882 }
883
884 static Socket telnet_socket(void *handle)
885 {
886 Telnet telnet = (Telnet) handle;
887 return telnet->s;
888 }
889
890 static int telnet_sendok(void *handle)
891 {
892 /* Telnet telnet = (Telnet) handle; */
893 return 1;
894 }
895
896 static void telnet_unthrottle(void *handle, int backlog)
897 {
898 Telnet telnet = (Telnet) handle;
899 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
900 }
901
902 static int telnet_ldisc(void *handle, int option)
903 {
904 Telnet telnet = (Telnet) handle;
905 if (option == LD_ECHO)
906 return telnet->echoing;
907 if (option == LD_EDIT)
908 return telnet->editing;
909 return FALSE;
910 }
911
912 static void telnet_provide_ldisc(void *handle, void *ldisc)
913 {
914 Telnet telnet = (Telnet) handle;
915 telnet->ldisc = ldisc;
916 }
917
918 static void telnet_provide_logctx(void *handle, void *logctx)
919 {
920 /* This is a stub. */
921 }
922
923 static int telnet_exitcode(void *handle)
924 {
925 /* Telnet telnet = (Telnet) handle; */
926 /* Telnet doesn't transmit exit codes back to the client */
927 return 0;
928 }
929
930 Backend telnet_backend = {
931 telnet_init,
932 telnet_send,
933 telnet_sendbuffer,
934 telnet_size,
935 telnet_special,
936 telnet_socket,
937 telnet_exitcode,
938 telnet_sendok,
939 telnet_ldisc,
940 telnet_provide_ldisc,
941 telnet_provide_logctx,
942 telnet_unthrottle,
943 23
944 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator