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Yet more global-removal. The static variables in logging.c are now
[u/mdw/putty] / telnet.c
1 #include <windows.h>
2 #include <stdio.h>
3 #include <stdlib.h>
4
5 #include "putty.h"
6
7 #ifndef FALSE
8 #define FALSE 0
9 #endif
10 #ifndef TRUE
11 #define TRUE 1
12 #endif
13
14 #define IAC 255 /* interpret as command: */
15 #define DONT 254 /* you are not to use option */
16 #define DO 253 /* please, you use option */
17 #define WONT 252 /* I won't use option */
18 #define WILL 251 /* I will use option */
19 #define SB 250 /* interpret as subnegotiation */
20 #define SE 240 /* end sub negotiation */
21
22 #define GA 249 /* you may reverse the line */
23 #define EL 248 /* erase the current line */
24 #define EC 247 /* erase the current character */
25 #define AYT 246 /* are you there */
26 #define AO 245 /* abort output--but let prog finish */
27 #define IP 244 /* interrupt process--permanently */
28 #define BREAK 243 /* break */
29 #define DM 242 /* data mark--for connect. cleaning */
30 #define NOP 241 /* nop */
31 #define EOR 239 /* end of record (transparent mode) */
32 #define ABORT 238 /* Abort process */
33 #define SUSP 237 /* Suspend process */
34 #define xEOF 236 /* End of file: EOF is already used... */
35
36 #define TELOPT_BINARY 0 /* 8-bit data path */
37 #define TELOPT_ECHO 1 /* echo */
38 #define TELOPT_RCP 2 /* prepare to reconnect */
39 #define TELOPT_SGA 3 /* suppress go ahead */
40 #define TELOPT_NAMS 4 /* approximate message size */
41 #define TELOPT_STATUS 5 /* give status */
42 #define TELOPT_TM 6 /* timing mark */
43 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */
44 #define TELOPT_NAOL 8 /* negotiate about output line width */
45 #define TELOPT_NAOP 9 /* negotiate about output page size */
46 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
47 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
48 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
49 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
50 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
51 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
52 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
53 #define TELOPT_XASCII 17 /* extended ascic character set */
54 #define TELOPT_LOGOUT 18 /* force logout */
55 #define TELOPT_BM 19 /* byte macro */
56 #define TELOPT_DET 20 /* data entry terminal */
57 #define TELOPT_SUPDUP 21 /* supdup protocol */
58 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
59 #define TELOPT_SNDLOC 23 /* send location */
60 #define TELOPT_TTYPE 24 /* terminal type */
61 #define TELOPT_EOR 25 /* end or record */
62 #define TELOPT_TUID 26 /* TACACS user identification */
63 #define TELOPT_OUTMRK 27 /* output marking */
64 #define TELOPT_TTYLOC 28 /* terminal location number */
65 #define TELOPT_3270REGIME 29 /* 3270 regime */
66 #define TELOPT_X3PAD 30 /* X.3 PAD */
67 #define TELOPT_NAWS 31 /* window size */
68 #define TELOPT_TSPEED 32 /* terminal speed */
69 #define TELOPT_LFLOW 33 /* remote flow control */
70 #define TELOPT_LINEMODE 34 /* Linemode option */
71 #define TELOPT_XDISPLOC 35 /* X Display Location */
72 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
73 #define TELOPT_AUTHENTICATION 37 /* Authenticate */
74 #define TELOPT_ENCRYPT 38 /* Encryption option */
75 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
76 #define TELOPT_EXOPL 255 /* extended-options-list */
77
78 #define TELQUAL_IS 0 /* option is... */
79 #define TELQUAL_SEND 1 /* send option */
80 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
81 #define BSD_VAR 1
82 #define BSD_VALUE 0
83 #define RFC_VAR 0
84 #define RFC_VALUE 1
85
86 #define CR 13
87 #define LF 10
88 #define NUL 0
89
90 #define iswritable(x) ( (x) != IAC && (x) != CR )
91
92 static char *telopt(int opt)
93 {
94 #define i(x) if (opt == TELOPT_ ## x) return #x;
95 i(BINARY);
96 i(ECHO);
97 i(RCP);
98 i(SGA);
99 i(NAMS);
100 i(STATUS);
101 i(TM);
102 i(RCTE);
103 i(NAOL);
104 i(NAOP);
105 i(NAOCRD);
106 i(NAOHTS);
107 i(NAOHTD);
108 i(NAOFFD);
109 i(NAOVTS);
110 i(NAOVTD);
111 i(NAOLFD);
112 i(XASCII);
113 i(LOGOUT);
114 i(BM);
115 i(DET);
116 i(SUPDUP);
117 i(SUPDUPOUTPUT);
118 i(SNDLOC);
119 i(TTYPE);
120 i(EOR);
121 i(TUID);
122 i(OUTMRK);
123 i(TTYLOC);
124 i(X3PAD);
125 i(NAWS);
126 i(TSPEED);
127 i(LFLOW);
128 i(LINEMODE);
129 i(XDISPLOC);
130 i(OLD_ENVIRON);
131 i(AUTHENTICATION);
132 i(ENCRYPT);
133 i(NEW_ENVIRON);
134 i(EXOPL);
135 #undef i
136 return "<unknown>";
137 }
138
139 static void telnet_size(void *handle, int width, int height);
140
141 struct Opt {
142 int send; /* what we initially send */
143 int nsend; /* -ve send if requested to stop it */
144 int ack, nak; /* +ve and -ve acknowledgements */
145 int option; /* the option code */
146 int index; /* index into telnet->opt_states[] */
147 enum {
148 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
149 } initial_state;
150 };
151
152 enum {
153 OPTINDEX_NAWS,
154 OPTINDEX_TSPEED,
155 OPTINDEX_TTYPE,
156 OPTINDEX_OENV,
157 OPTINDEX_NENV,
158 OPTINDEX_ECHO,
159 OPTINDEX_WE_SGA,
160 OPTINDEX_THEY_SGA,
161 NUM_OPTS
162 };
163
164 static const struct Opt o_naws =
165 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
166 static const struct Opt o_tspeed =
167 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
168 static const struct Opt o_ttype =
169 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
170 static const struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
171 OPTINDEX_OENV, INACTIVE
172 };
173 static const struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
174 OPTINDEX_NENV, REQUESTED
175 };
176 static const struct Opt o_echo =
177 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
178 static const struct Opt o_we_sga =
179 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
180 static const struct Opt o_they_sga =
181 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
182
183 static const struct Opt *const opts[] = {
184 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
185 &o_we_sga, &o_they_sga, NULL
186 };
187
188 typedef struct telnet_tag {
189 const struct plug_function_table *fn;
190 /* the above field _must_ be first in the structure */
191
192 Socket s;
193
194 void *frontend;
195 void *ldisc;
196 int term_width, term_height;
197
198 int opt_states[NUM_OPTS];
199
200 int echoing, editing;
201 int activated;
202 int bufsize;
203 int in_synch;
204 int sb_opt, sb_len;
205 char *sb_buf;
206 int sb_size;
207
208 enum {
209 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
210 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
211 } state;
212
213 } *Telnet;
214
215 #define TELNET_MAX_BACKLOG 4096
216
217 #define SB_DELTA 1024
218
219 static void c_write1(Telnet telnet, int c)
220 {
221 int backlog;
222 char cc = (char) c;
223 backlog = from_backend(telnet->frontend, 0, &cc, 1);
224 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
225 }
226
227 static void log_option(Telnet telnet, char *sender, int cmd, int option)
228 {
229 char buf[50];
230 sprintf(buf, "%s:\t%s %s", sender,
231 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
232 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
233 telopt(option));
234 logevent(telnet->frontend, buf);
235 }
236
237 static void send_opt(Telnet telnet, int cmd, int option)
238 {
239 unsigned char b[3];
240
241 b[0] = IAC;
242 b[1] = cmd;
243 b[2] = option;
244 telnet->bufsize = sk_write(telnet->s, b, 3);
245 log_option(telnet, "client", cmd, option);
246 }
247
248 static void deactivate_option(Telnet telnet, const struct Opt *o)
249 {
250 if (telnet->opt_states[o->index] == REQUESTED ||
251 telnet->opt_states[o->index] == ACTIVE)
252 send_opt(telnet, o->nsend, o->option);
253 telnet->opt_states[o->index] = REALLY_INACTIVE;
254 }
255
256 /*
257 * Generate side effects of enabling or disabling an option.
258 */
259 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
260 {
261 if (o->option == TELOPT_ECHO && o->send == DO)
262 telnet->echoing = !enabled;
263 else if (o->option == TELOPT_SGA && o->send == DO)
264 telnet->editing = !enabled;
265 if (telnet->ldisc) /* cause ldisc to notice the change */
266 ldisc_send(telnet->ldisc, NULL, 0, 0);
267
268 /* Ensure we get the minimum options */
269 if (!telnet->activated) {
270 if (telnet->opt_states[o_echo.index] == INACTIVE) {
271 telnet->opt_states[o_echo.index] = REQUESTED;
272 send_opt(telnet, o_echo.send, o_echo.option);
273 }
274 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
275 telnet->opt_states[o_we_sga.index] = REQUESTED;
276 send_opt(telnet, o_we_sga.send, o_we_sga.option);
277 }
278 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
279 telnet->opt_states[o_they_sga.index] = REQUESTED;
280 send_opt(telnet, o_they_sga.send, o_they_sga.option);
281 }
282 telnet->activated = TRUE;
283 }
284 }
285
286 static void activate_option(Telnet telnet, const struct Opt *o)
287 {
288 if (o->send == WILL && o->option == TELOPT_NAWS)
289 telnet_size(telnet, telnet->term_width, telnet->term_height);
290 if (o->send == WILL &&
291 (o->option == TELOPT_NEW_ENVIRON ||
292 o->option == TELOPT_OLD_ENVIRON)) {
293 /*
294 * We may only have one kind of ENVIRON going at a time.
295 * This is a hack, but who cares.
296 */
297 deactivate_option(telnet, o->option ==
298 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
299 }
300 option_side_effects(telnet, o, 1);
301 }
302
303 static void refused_option(Telnet telnet, const struct Opt *o)
304 {
305 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
306 telnet->opt_states[o_oenv.index] == INACTIVE) {
307 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
308 telnet->opt_states[o_oenv.index] = REQUESTED;
309 }
310 option_side_effects(telnet, o, 0);
311 }
312
313 static void proc_rec_opt(Telnet telnet, int cmd, int option)
314 {
315 const struct Opt *const *o;
316
317 log_option(telnet, "server", cmd, option);
318 for (o = opts; *o; o++) {
319 if ((*o)->option == option && (*o)->ack == cmd) {
320 switch (telnet->opt_states[(*o)->index]) {
321 case REQUESTED:
322 telnet->opt_states[(*o)->index] = ACTIVE;
323 activate_option(telnet, *o);
324 break;
325 case ACTIVE:
326 break;
327 case INACTIVE:
328 telnet->opt_states[(*o)->index] = ACTIVE;
329 send_opt(telnet, (*o)->send, option);
330 activate_option(telnet, *o);
331 break;
332 case REALLY_INACTIVE:
333 send_opt(telnet, (*o)->nsend, option);
334 break;
335 }
336 return;
337 } else if ((*o)->option == option && (*o)->nak == cmd) {
338 switch (telnet->opt_states[(*o)->index]) {
339 case REQUESTED:
340 telnet->opt_states[(*o)->index] = INACTIVE;
341 refused_option(telnet, *o);
342 break;
343 case ACTIVE:
344 telnet->opt_states[(*o)->index] = INACTIVE;
345 send_opt(telnet, (*o)->nsend, option);
346 option_side_effects(telnet, *o, 0);
347 break;
348 case INACTIVE:
349 case REALLY_INACTIVE:
350 break;
351 }
352 return;
353 }
354 }
355 /*
356 * If we reach here, the option was one we weren't prepared to
357 * cope with. So send a negative ack.
358 */
359 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
360 }
361
362 static void process_subneg(Telnet telnet)
363 {
364 unsigned char b[2048], *p, *q;
365 int var, value, n;
366 char *e;
367
368 switch (telnet->sb_opt) {
369 case TELOPT_TSPEED:
370 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
371 char logbuf[sizeof(cfg.termspeed) + 80];
372 b[0] = IAC;
373 b[1] = SB;
374 b[2] = TELOPT_TSPEED;
375 b[3] = TELQUAL_IS;
376 strcpy(b + 4, cfg.termspeed);
377 n = 4 + strlen(cfg.termspeed);
378 b[n] = IAC;
379 b[n + 1] = SE;
380 telnet->bufsize = sk_write(telnet->s, b, n + 2);
381 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
382 sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
383 logevent(telnet->frontend, logbuf);
384 } else
385 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
386 break;
387 case TELOPT_TTYPE:
388 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
389 char logbuf[sizeof(cfg.termtype) + 80];
390 b[0] = IAC;
391 b[1] = SB;
392 b[2] = TELOPT_TTYPE;
393 b[3] = TELQUAL_IS;
394 for (n = 0; cfg.termtype[n]; n++)
395 b[n + 4] = (cfg.termtype[n] >= 'a'
396 && cfg.termtype[n] <=
397 'z' ? cfg.termtype[n] + 'A' -
398 'a' : cfg.termtype[n]);
399 b[n + 4] = IAC;
400 b[n + 5] = SE;
401 telnet->bufsize = sk_write(telnet->s, b, n + 6);
402 b[n + 4] = 0;
403 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
404 sprintf(logbuf, "client:\tSB TTYPE IS %s", b + 4);
405 logevent(telnet->frontend, logbuf);
406 } else
407 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
408 break;
409 case TELOPT_OLD_ENVIRON:
410 case TELOPT_NEW_ENVIRON:
411 p = telnet->sb_buf;
412 q = p + telnet->sb_len;
413 if (p < q && *p == TELQUAL_SEND) {
414 char logbuf[50];
415 p++;
416 sprintf(logbuf, "server:\tSB %s SEND", telopt(telnet->sb_opt));
417 logevent(telnet->frontend, logbuf);
418 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
419 if (cfg.rfc_environ) {
420 value = RFC_VALUE;
421 var = RFC_VAR;
422 } else {
423 value = BSD_VALUE;
424 var = BSD_VAR;
425 }
426 /*
427 * Try to guess the sense of VAR and VALUE.
428 */
429 while (p < q) {
430 if (*p == RFC_VAR) {
431 value = RFC_VALUE;
432 var = RFC_VAR;
433 } else if (*p == BSD_VAR) {
434 value = BSD_VALUE;
435 var = BSD_VAR;
436 }
437 p++;
438 }
439 } else {
440 /*
441 * With NEW_ENVIRON, the sense of VAR and VALUE
442 * isn't in doubt.
443 */
444 value = RFC_VALUE;
445 var = RFC_VAR;
446 }
447 b[0] = IAC;
448 b[1] = SB;
449 b[2] = telnet->sb_opt;
450 b[3] = TELQUAL_IS;
451 n = 4;
452 e = cfg.environmt;
453 while (*e) {
454 b[n++] = var;
455 while (*e && *e != '\t')
456 b[n++] = *e++;
457 if (*e == '\t')
458 e++;
459 b[n++] = value;
460 while (*e)
461 b[n++] = *e++;
462 e++;
463 }
464 if (*cfg.username) {
465 b[n++] = var;
466 b[n++] = 'U';
467 b[n++] = 'S';
468 b[n++] = 'E';
469 b[n++] = 'R';
470 b[n++] = value;
471 e = cfg.username;
472 while (*e)
473 b[n++] = *e++;
474 }
475 b[n++] = IAC;
476 b[n++] = SE;
477 telnet->bufsize = sk_write(telnet->s, b, n);
478 sprintf(logbuf, "client:\tSB %s IS %s", telopt(telnet->sb_opt),
479 n == 6 ? "<nothing>" : "<stuff>");
480 logevent(telnet->frontend, logbuf);
481 }
482 break;
483 }
484 }
485
486 static void do_telnet_read(Telnet telnet, char *buf, int len)
487 {
488
489 while (len--) {
490 int c = (unsigned char) *buf++;
491
492 switch (telnet->state) {
493 case TOP_LEVEL:
494 case SEENCR:
495 if (c == NUL && telnet->state == SEENCR)
496 telnet->state = TOP_LEVEL;
497 else if (c == IAC)
498 telnet->state = SEENIAC;
499 else {
500 if (!telnet->in_synch)
501 c_write1(telnet, c);
502
503 #if 1
504 /* I can't get the F***ing winsock to insert the urgent IAC
505 * into the right position! Even with SO_OOBINLINE it gives
506 * it to recv too soon. And of course the DM byte (that
507 * arrives in the same packet!) appears several K later!!
508 *
509 * Oh well, we do get the DM in the right place so I'll
510 * just stop hiding on the next 0xf2 and hope for the best.
511 */
512 else if (c == DM)
513 telnet->in_synch = 0;
514 #endif
515 if (c == CR)
516 telnet->state = SEENCR;
517 else
518 telnet->state = TOP_LEVEL;
519 }
520 break;
521 case SEENIAC:
522 if (c == DO)
523 telnet->state = SEENDO;
524 else if (c == DONT)
525 telnet->state = SEENDONT;
526 else if (c == WILL)
527 telnet->state = SEENWILL;
528 else if (c == WONT)
529 telnet->state = SEENWONT;
530 else if (c == SB)
531 telnet->state = SEENSB;
532 else if (c == DM) {
533 telnet->in_synch = 0;
534 telnet->state = TOP_LEVEL;
535 } else {
536 /* ignore everything else; print it if it's IAC */
537 if (c == IAC) {
538 c_write1(telnet, c);
539 }
540 telnet->state = TOP_LEVEL;
541 }
542 break;
543 case SEENWILL:
544 proc_rec_opt(telnet, WILL, c);
545 telnet->state = TOP_LEVEL;
546 break;
547 case SEENWONT:
548 proc_rec_opt(telnet, WONT, c);
549 telnet->state = TOP_LEVEL;
550 break;
551 case SEENDO:
552 proc_rec_opt(telnet, DO, c);
553 telnet->state = TOP_LEVEL;
554 break;
555 case SEENDONT:
556 proc_rec_opt(telnet, DONT, c);
557 telnet->state = TOP_LEVEL;
558 break;
559 case SEENSB:
560 telnet->sb_opt = c;
561 telnet->sb_len = 0;
562 telnet->state = SUBNEGOT;
563 break;
564 case SUBNEGOT:
565 if (c == IAC)
566 telnet->state = SUBNEG_IAC;
567 else {
568 subneg_addchar:
569 if (telnet->sb_len >= telnet->sb_size) {
570 char *newbuf;
571 telnet->sb_size += SB_DELTA;
572 newbuf = (telnet->sb_buf ?
573 srealloc(telnet->sb_buf, telnet->sb_size) :
574 smalloc(telnet->sb_size));
575 if (newbuf)
576 telnet->sb_buf = newbuf;
577 else
578 telnet->sb_size -= SB_DELTA;
579 }
580 if (telnet->sb_len < telnet->sb_size)
581 telnet->sb_buf[telnet->sb_len++] = c;
582 telnet->state = SUBNEGOT; /* in case we came here by goto */
583 }
584 break;
585 case SUBNEG_IAC:
586 if (c != SE)
587 goto subneg_addchar; /* yes, it's a hack, I know, but... */
588 else {
589 process_subneg(telnet);
590 telnet->state = TOP_LEVEL;
591 }
592 break;
593 }
594 }
595 }
596
597 static int telnet_closing(Plug plug, char *error_msg, int error_code,
598 int calling_back)
599 {
600 Telnet telnet = (Telnet) plug;
601
602 if (telnet->s) {
603 sk_close(telnet->s);
604 telnet->s = NULL;
605 }
606 if (error_msg) {
607 /* A socket error has occurred. */
608 logevent(telnet->frontend, error_msg);
609 connection_fatal("%s", error_msg);
610 } /* Otherwise, the remote side closed the connection normally. */
611 return 0;
612 }
613
614 static int telnet_receive(Plug plug, int urgent, char *data, int len)
615 {
616 Telnet telnet = (Telnet) plug;
617 if (urgent)
618 telnet->in_synch = TRUE;
619 do_telnet_read(telnet, data, len);
620 return 1;
621 }
622
623 static void telnet_sent(Plug plug, int bufsize)
624 {
625 Telnet telnet = (Telnet) plug;
626 telnet->bufsize = bufsize;
627 }
628
629 /*
630 * Called to set up the Telnet connection.
631 *
632 * Returns an error message, or NULL on success.
633 *
634 * Also places the canonical host name into `realhost'. It must be
635 * freed by the caller.
636 */
637 static char *telnet_init(void *frontend_handle, void **backend_handle,
638 char *host, int port, char **realhost, int nodelay)
639 {
640 static const struct plug_function_table fn_table = {
641 telnet_closing,
642 telnet_receive,
643 telnet_sent
644 };
645 SockAddr addr;
646 char *err;
647 Telnet telnet;
648
649 telnet = smalloc(sizeof(*telnet));
650 telnet->fn = &fn_table;
651 telnet->s = NULL;
652 telnet->echoing = TRUE;
653 telnet->editing = TRUE;
654 telnet->activated = FALSE;
655 telnet->sb_buf = NULL;
656 telnet->sb_size = 0;
657 telnet->frontend = frontend_handle;
658 telnet->term_width = cfg.width;
659 telnet->term_height = cfg.height;
660 telnet->state = TOP_LEVEL;
661 *backend_handle = telnet;
662
663 /*
664 * Try to find host.
665 */
666 {
667 char buf[200];
668 sprintf(buf, "Looking up host \"%.170s\"", host);
669 logevent(telnet->frontend, buf);
670 }
671 addr = sk_namelookup(host, realhost);
672 if ((err = sk_addr_error(addr)))
673 return err;
674
675 if (port < 0)
676 port = 23; /* default telnet port */
677
678 /*
679 * Open socket.
680 */
681 {
682 char buf[200], addrbuf[100];
683 sk_getaddr(addr, addrbuf, 100);
684 sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
685 logevent(telnet->frontend, buf);
686 }
687 telnet->s = new_connection(addr, *realhost, port, 0, 1,
688 nodelay, (Plug) telnet);
689 if ((err = sk_socket_error(telnet->s)))
690 return err;
691
692 sk_addr_free(addr);
693
694 /*
695 * Initialise option states.
696 */
697 if (cfg.passive_telnet) {
698 const struct Opt *const *o;
699
700 for (o = opts; *o; o++)
701 telnet->opt_states[(*o)->index] = INACTIVE;
702 } else {
703 const struct Opt *const *o;
704
705 for (o = opts; *o; o++) {
706 telnet->opt_states[(*o)->index] = (*o)->initial_state;
707 if (telnet->opt_states[(*o)->index] == REQUESTED)
708 send_opt(telnet, (*o)->send, (*o)->option);
709 }
710 telnet->activated = TRUE;
711 }
712
713 /*
714 * Set up SYNCH state.
715 */
716 telnet->in_synch = FALSE;
717
718 return NULL;
719 }
720
721 /*
722 * Called to send data down the Telnet connection.
723 */
724 static int telnet_send(void *handle, char *buf, int len)
725 {
726 Telnet telnet = (Telnet) handle;
727 char *p;
728 static unsigned char iac[2] = { IAC, IAC };
729 static unsigned char cr[2] = { CR, NUL };
730 #if 0
731 static unsigned char nl[2] = { CR, LF };
732 #endif
733
734 if (telnet->s == NULL)
735 return 0;
736
737 p = buf;
738 while (p < buf + len) {
739 char *q = p;
740
741 while (iswritable((unsigned char) *p) && p < buf + len)
742 p++;
743 telnet->bufsize = sk_write(telnet->s, q, p - q);
744
745 while (p < buf + len && !iswritable((unsigned char) *p)) {
746 telnet->bufsize =
747 sk_write(telnet->s, (unsigned char) *p == IAC ? iac : cr, 2);
748 p++;
749 }
750 }
751
752 return telnet->bufsize;
753 }
754
755 /*
756 * Called to query the current socket sendability status.
757 */
758 static int telnet_sendbuffer(void *handle)
759 {
760 Telnet telnet = (Telnet) handle;
761 return telnet->bufsize;
762 }
763
764 /*
765 * Called to set the size of the window from Telnet's POV.
766 */
767 static void telnet_size(void *handle, int width, int height)
768 {
769 Telnet telnet = (Telnet) handle;
770 unsigned char b[16];
771 char logbuf[50];
772
773 telnet->term_width = width;
774 telnet->term_height = height;
775
776 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
777 return;
778 b[0] = IAC;
779 b[1] = SB;
780 b[2] = TELOPT_NAWS;
781 b[3] = telnet->term_width >> 8;
782 b[4] = telnet->term_width & 0xFF;
783 b[5] = telnet->term_height >> 8;
784 b[6] = telnet->term_height & 0xFF;
785 b[7] = IAC;
786 b[8] = SE;
787 telnet->bufsize = sk_write(telnet->s, b, 9);
788 sprintf(logbuf, "client:\tSB NAWS %d,%d",
789 ((unsigned char) b[3] << 8) + (unsigned char) b[4],
790 ((unsigned char) b[5] << 8) + (unsigned char) b[6]);
791 logevent(telnet->frontend, logbuf);
792 }
793
794 /*
795 * Send Telnet special codes.
796 */
797 static void telnet_special(void *handle, Telnet_Special code)
798 {
799 Telnet telnet = (Telnet) handle;
800 unsigned char b[2];
801
802 if (telnet->s == NULL)
803 return;
804
805 b[0] = IAC;
806 switch (code) {
807 case TS_AYT:
808 b[1] = AYT;
809 telnet->bufsize = sk_write(telnet->s, b, 2);
810 break;
811 case TS_BRK:
812 b[1] = BREAK;
813 telnet->bufsize = sk_write(telnet->s, b, 2);
814 break;
815 case TS_EC:
816 b[1] = EC;
817 telnet->bufsize = sk_write(telnet->s, b, 2);
818 break;
819 case TS_EL:
820 b[1] = EL;
821 telnet->bufsize = sk_write(telnet->s, b, 2);
822 break;
823 case TS_GA:
824 b[1] = GA;
825 telnet->bufsize = sk_write(telnet->s, b, 2);
826 break;
827 case TS_NOP:
828 b[1] = NOP;
829 telnet->bufsize = sk_write(telnet->s, b, 2);
830 break;
831 case TS_ABORT:
832 b[1] = ABORT;
833 telnet->bufsize = sk_write(telnet->s, b, 2);
834 break;
835 case TS_AO:
836 b[1] = AO;
837 telnet->bufsize = sk_write(telnet->s, b, 2);
838 break;
839 case TS_IP:
840 b[1] = IP;
841 telnet->bufsize = sk_write(telnet->s, b, 2);
842 break;
843 case TS_SUSP:
844 b[1] = SUSP;
845 telnet->bufsize = sk_write(telnet->s, b, 2);
846 break;
847 case TS_EOR:
848 b[1] = EOR;
849 telnet->bufsize = sk_write(telnet->s, b, 2);
850 break;
851 case TS_EOF:
852 b[1] = xEOF;
853 telnet->bufsize = sk_write(telnet->s, b, 2);
854 break;
855 case TS_EOL:
856 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
857 break;
858 case TS_SYNCH:
859 b[1] = DM;
860 telnet->bufsize = sk_write(telnet->s, b, 1);
861 telnet->bufsize = sk_write_oob(telnet->s, b + 1, 1);
862 break;
863 case TS_RECHO:
864 if (telnet->opt_states[o_echo.index] == INACTIVE ||
865 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
866 telnet->opt_states[o_echo.index] = REQUESTED;
867 send_opt(telnet, o_echo.send, o_echo.option);
868 }
869 break;
870 case TS_LECHO:
871 if (telnet->opt_states[o_echo.index] == ACTIVE) {
872 telnet->opt_states[o_echo.index] = REQUESTED;
873 send_opt(telnet, o_echo.nsend, o_echo.option);
874 }
875 break;
876 case TS_PING:
877 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
878 b[1] = NOP;
879 telnet->bufsize = sk_write(telnet->s, b, 2);
880 }
881 break;
882 }
883 }
884
885 static Socket telnet_socket(void *handle)
886 {
887 Telnet telnet = (Telnet) handle;
888 return telnet->s;
889 }
890
891 static int telnet_sendok(void *handle)
892 {
893 Telnet telnet = (Telnet) handle;
894 return 1;
895 }
896
897 static void telnet_unthrottle(void *handle, int backlog)
898 {
899 Telnet telnet = (Telnet) handle;
900 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
901 }
902
903 static int telnet_ldisc(void *handle, int option)
904 {
905 Telnet telnet = (Telnet) handle;
906 if (option == LD_ECHO)
907 return telnet->echoing;
908 if (option == LD_EDIT)
909 return telnet->editing;
910 return FALSE;
911 }
912
913 static void telnet_provide_ldisc(void *handle, void *ldisc)
914 {
915 Telnet telnet = (Telnet) handle;
916 telnet->ldisc = ldisc;
917 }
918
919 static void telnet_provide_logctx(void *handle, void *logctx)
920 {
921 /* This is a stub. */
922 }
923
924 static int telnet_exitcode(void *handle)
925 {
926 Telnet telnet = (Telnet) handle;
927 /* Telnet doesn't transmit exit codes back to the client */
928 return 0;
929 }
930
931 Backend telnet_backend = {
932 telnet_init,
933 telnet_send,
934 telnet_sendbuffer,
935 telnet_size,
936 telnet_special,
937 telnet_socket,
938 telnet_exitcode,
939 telnet_sendok,
940 telnet_ldisc,
941 telnet_provide_ldisc,
942 telnet_provide_logctx,
943 telnet_unthrottle,
944 23
945 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator