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Another valgrind-caught error. This one has apparently been there
[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 /*
230 * The strange-looking "<?""?>" below is there to avoid a
231 * trigraph - a double question mark followed by > maps to a
232 * closing brace character!
233 */
234 sprintf(buf, "%s:\t%s %s", sender,
235 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
236 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
237 telopt(option));
238 logevent(telnet->frontend, buf);
239 }
240
241 static void send_opt(Telnet telnet, int cmd, int option)
242 {
243 unsigned char b[3];
244
245 b[0] = IAC;
246 b[1] = cmd;
247 b[2] = option;
248 telnet->bufsize = sk_write(telnet->s, b, 3);
249 log_option(telnet, "client", cmd, option);
250 }
251
252 static void deactivate_option(Telnet telnet, const struct Opt *o)
253 {
254 if (telnet->opt_states[o->index] == REQUESTED ||
255 telnet->opt_states[o->index] == ACTIVE)
256 send_opt(telnet, o->nsend, o->option);
257 telnet->opt_states[o->index] = REALLY_INACTIVE;
258 }
259
260 /*
261 * Generate side effects of enabling or disabling an option.
262 */
263 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
264 {
265 if (o->option == TELOPT_ECHO && o->send == DO)
266 telnet->echoing = !enabled;
267 else if (o->option == TELOPT_SGA && o->send == DO)
268 telnet->editing = !enabled;
269 if (telnet->ldisc) /* cause ldisc to notice the change */
270 ldisc_send(telnet->ldisc, NULL, 0, 0);
271
272 /* Ensure we get the minimum options */
273 if (!telnet->activated) {
274 if (telnet->opt_states[o_echo.index] == INACTIVE) {
275 telnet->opt_states[o_echo.index] = REQUESTED;
276 send_opt(telnet, o_echo.send, o_echo.option);
277 }
278 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
279 telnet->opt_states[o_we_sga.index] = REQUESTED;
280 send_opt(telnet, o_we_sga.send, o_we_sga.option);
281 }
282 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
283 telnet->opt_states[o_they_sga.index] = REQUESTED;
284 send_opt(telnet, o_they_sga.send, o_they_sga.option);
285 }
286 telnet->activated = TRUE;
287 }
288 }
289
290 static void activate_option(Telnet telnet, const struct Opt *o)
291 {
292 if (o->send == WILL && o->option == TELOPT_NAWS)
293 telnet_size(telnet, telnet->term_width, telnet->term_height);
294 if (o->send == WILL &&
295 (o->option == TELOPT_NEW_ENVIRON ||
296 o->option == TELOPT_OLD_ENVIRON)) {
297 /*
298 * We may only have one kind of ENVIRON going at a time.
299 * This is a hack, but who cares.
300 */
301 deactivate_option(telnet, o->option ==
302 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
303 }
304 option_side_effects(telnet, o, 1);
305 }
306
307 static void refused_option(Telnet telnet, const struct Opt *o)
308 {
309 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
310 telnet->opt_states[o_oenv.index] == INACTIVE) {
311 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
312 telnet->opt_states[o_oenv.index] = REQUESTED;
313 }
314 option_side_effects(telnet, o, 0);
315 }
316
317 static void proc_rec_opt(Telnet telnet, int cmd, int option)
318 {
319 const struct Opt *const *o;
320
321 log_option(telnet, "server", cmd, option);
322 for (o = opts; *o; o++) {
323 if ((*o)->option == option && (*o)->ack == cmd) {
324 switch (telnet->opt_states[(*o)->index]) {
325 case REQUESTED:
326 telnet->opt_states[(*o)->index] = ACTIVE;
327 activate_option(telnet, *o);
328 break;
329 case ACTIVE:
330 break;
331 case INACTIVE:
332 telnet->opt_states[(*o)->index] = ACTIVE;
333 send_opt(telnet, (*o)->send, option);
334 activate_option(telnet, *o);
335 break;
336 case REALLY_INACTIVE:
337 send_opt(telnet, (*o)->nsend, option);
338 break;
339 }
340 return;
341 } else if ((*o)->option == option && (*o)->nak == cmd) {
342 switch (telnet->opt_states[(*o)->index]) {
343 case REQUESTED:
344 telnet->opt_states[(*o)->index] = INACTIVE;
345 refused_option(telnet, *o);
346 break;
347 case ACTIVE:
348 telnet->opt_states[(*o)->index] = INACTIVE;
349 send_opt(telnet, (*o)->nsend, option);
350 option_side_effects(telnet, *o, 0);
351 break;
352 case INACTIVE:
353 case REALLY_INACTIVE:
354 break;
355 }
356 return;
357 }
358 }
359 /*
360 * If we reach here, the option was one we weren't prepared to
361 * cope with. So send a negative ack.
362 */
363 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
364 }
365
366 static void process_subneg(Telnet telnet)
367 {
368 unsigned char b[2048], *p, *q;
369 int var, value, n;
370 char *e;
371
372 switch (telnet->sb_opt) {
373 case TELOPT_TSPEED:
374 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
375 char logbuf[sizeof(cfg.termspeed) + 80];
376 b[0] = IAC;
377 b[1] = SB;
378 b[2] = TELOPT_TSPEED;
379 b[3] = TELQUAL_IS;
380 strcpy(b + 4, cfg.termspeed);
381 n = 4 + strlen(cfg.termspeed);
382 b[n] = IAC;
383 b[n + 1] = SE;
384 telnet->bufsize = sk_write(telnet->s, b, n + 2);
385 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
386 sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
387 logevent(telnet->frontend, logbuf);
388 } else
389 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
390 break;
391 case TELOPT_TTYPE:
392 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
393 char logbuf[sizeof(cfg.termtype) + 80];
394 b[0] = IAC;
395 b[1] = SB;
396 b[2] = TELOPT_TTYPE;
397 b[3] = TELQUAL_IS;
398 for (n = 0; cfg.termtype[n]; n++)
399 b[n + 4] = (cfg.termtype[n] >= 'a'
400 && cfg.termtype[n] <=
401 'z' ? cfg.termtype[n] + 'A' -
402 'a' : cfg.termtype[n]);
403 b[n + 4] = IAC;
404 b[n + 5] = SE;
405 telnet->bufsize = sk_write(telnet->s, b, n + 6);
406 b[n + 4] = 0;
407 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
408 sprintf(logbuf, "client:\tSB TTYPE IS %s", b + 4);
409 logevent(telnet->frontend, logbuf);
410 } else
411 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
412 break;
413 case TELOPT_OLD_ENVIRON:
414 case TELOPT_NEW_ENVIRON:
415 p = telnet->sb_buf;
416 q = p + telnet->sb_len;
417 if (p < q && *p == TELQUAL_SEND) {
418 char logbuf[50];
419 p++;
420 sprintf(logbuf, "server:\tSB %s SEND", telopt(telnet->sb_opt));
421 logevent(telnet->frontend, logbuf);
422 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
423 if (cfg.rfc_environ) {
424 value = RFC_VALUE;
425 var = RFC_VAR;
426 } else {
427 value = BSD_VALUE;
428 var = BSD_VAR;
429 }
430 /*
431 * Try to guess the sense of VAR and VALUE.
432 */
433 while (p < q) {
434 if (*p == RFC_VAR) {
435 value = RFC_VALUE;
436 var = RFC_VAR;
437 } else if (*p == BSD_VAR) {
438 value = BSD_VALUE;
439 var = BSD_VAR;
440 }
441 p++;
442 }
443 } else {
444 /*
445 * With NEW_ENVIRON, the sense of VAR and VALUE
446 * isn't in doubt.
447 */
448 value = RFC_VALUE;
449 var = RFC_VAR;
450 }
451 b[0] = IAC;
452 b[1] = SB;
453 b[2] = telnet->sb_opt;
454 b[3] = TELQUAL_IS;
455 n = 4;
456 e = cfg.environmt;
457 while (*e) {
458 b[n++] = var;
459 while (*e && *e != '\t')
460 b[n++] = *e++;
461 if (*e == '\t')
462 e++;
463 b[n++] = value;
464 while (*e)
465 b[n++] = *e++;
466 e++;
467 }
468 if (*cfg.username) {
469 b[n++] = var;
470 b[n++] = 'U';
471 b[n++] = 'S';
472 b[n++] = 'E';
473 b[n++] = 'R';
474 b[n++] = value;
475 e = cfg.username;
476 while (*e)
477 b[n++] = *e++;
478 }
479 b[n++] = IAC;
480 b[n++] = SE;
481 telnet->bufsize = sk_write(telnet->s, b, n);
482 sprintf(logbuf, "client:\tSB %s IS %s", telopt(telnet->sb_opt),
483 n == 6 ? "<nothing>" : "<stuff>");
484 logevent(telnet->frontend, logbuf);
485 }
486 break;
487 }
488 }
489
490 static void do_telnet_read(Telnet telnet, char *buf, int len)
491 {
492
493 while (len--) {
494 int c = (unsigned char) *buf++;
495
496 switch (telnet->state) {
497 case TOP_LEVEL:
498 case SEENCR:
499 if (c == NUL && telnet->state == SEENCR)
500 telnet->state = TOP_LEVEL;
501 else if (c == IAC)
502 telnet->state = SEENIAC;
503 else {
504 if (!telnet->in_synch)
505 c_write1(telnet, c);
506
507 #if 1
508 /* I can't get the F***ing winsock to insert the urgent IAC
509 * into the right position! Even with SO_OOBINLINE it gives
510 * it to recv too soon. And of course the DM byte (that
511 * arrives in the same packet!) appears several K later!!
512 *
513 * Oh well, we do get the DM in the right place so I'll
514 * just stop hiding on the next 0xf2 and hope for the best.
515 */
516 else if (c == DM)
517 telnet->in_synch = 0;
518 #endif
519 if (c == CR)
520 telnet->state = SEENCR;
521 else
522 telnet->state = TOP_LEVEL;
523 }
524 break;
525 case SEENIAC:
526 if (c == DO)
527 telnet->state = SEENDO;
528 else if (c == DONT)
529 telnet->state = SEENDONT;
530 else if (c == WILL)
531 telnet->state = SEENWILL;
532 else if (c == WONT)
533 telnet->state = SEENWONT;
534 else if (c == SB)
535 telnet->state = SEENSB;
536 else if (c == DM) {
537 telnet->in_synch = 0;
538 telnet->state = TOP_LEVEL;
539 } else {
540 /* ignore everything else; print it if it's IAC */
541 if (c == IAC) {
542 c_write1(telnet, c);
543 }
544 telnet->state = TOP_LEVEL;
545 }
546 break;
547 case SEENWILL:
548 proc_rec_opt(telnet, WILL, c);
549 telnet->state = TOP_LEVEL;
550 break;
551 case SEENWONT:
552 proc_rec_opt(telnet, WONT, c);
553 telnet->state = TOP_LEVEL;
554 break;
555 case SEENDO:
556 proc_rec_opt(telnet, DO, c);
557 telnet->state = TOP_LEVEL;
558 break;
559 case SEENDONT:
560 proc_rec_opt(telnet, DONT, c);
561 telnet->state = TOP_LEVEL;
562 break;
563 case SEENSB:
564 telnet->sb_opt = c;
565 telnet->sb_len = 0;
566 telnet->state = SUBNEGOT;
567 break;
568 case SUBNEGOT:
569 if (c == IAC)
570 telnet->state = SUBNEG_IAC;
571 else {
572 subneg_addchar:
573 if (telnet->sb_len >= telnet->sb_size) {
574 char *newbuf;
575 telnet->sb_size += SB_DELTA;
576 newbuf = (telnet->sb_buf ?
577 srealloc(telnet->sb_buf, telnet->sb_size) :
578 smalloc(telnet->sb_size));
579 if (newbuf)
580 telnet->sb_buf = newbuf;
581 else
582 telnet->sb_size -= SB_DELTA;
583 }
584 if (telnet->sb_len < telnet->sb_size)
585 telnet->sb_buf[telnet->sb_len++] = c;
586 telnet->state = SUBNEGOT; /* in case we came here by goto */
587 }
588 break;
589 case SUBNEG_IAC:
590 if (c != SE)
591 goto subneg_addchar; /* yes, it's a hack, I know, but... */
592 else {
593 process_subneg(telnet);
594 telnet->state = TOP_LEVEL;
595 }
596 break;
597 }
598 }
599 }
600
601 static int telnet_closing(Plug plug, char *error_msg, int error_code,
602 int calling_back)
603 {
604 Telnet telnet = (Telnet) plug;
605
606 if (telnet->s) {
607 sk_close(telnet->s);
608 telnet->s = NULL;
609 }
610 if (error_msg) {
611 /* A socket error has occurred. */
612 logevent(telnet->frontend, error_msg);
613 connection_fatal("%s", error_msg);
614 } /* Otherwise, the remote side closed the connection normally. */
615 return 0;
616 }
617
618 static int telnet_receive(Plug plug, int urgent, char *data, int len)
619 {
620 Telnet telnet = (Telnet) plug;
621 if (urgent)
622 telnet->in_synch = TRUE;
623 do_telnet_read(telnet, data, len);
624 return 1;
625 }
626
627 static void telnet_sent(Plug plug, int bufsize)
628 {
629 Telnet telnet = (Telnet) plug;
630 telnet->bufsize = bufsize;
631 }
632
633 /*
634 * Called to set up the Telnet connection.
635 *
636 * Returns an error message, or NULL on success.
637 *
638 * Also places the canonical host name into `realhost'. It must be
639 * freed by the caller.
640 */
641 static char *telnet_init(void *frontend_handle, void **backend_handle,
642 char *host, int port, char **realhost, int nodelay)
643 {
644 static const struct plug_function_table fn_table = {
645 telnet_closing,
646 telnet_receive,
647 telnet_sent
648 };
649 SockAddr addr;
650 char *err;
651 Telnet telnet;
652
653 telnet = smalloc(sizeof(*telnet));
654 telnet->fn = &fn_table;
655 telnet->s = NULL;
656 telnet->echoing = TRUE;
657 telnet->editing = TRUE;
658 telnet->activated = FALSE;
659 telnet->sb_buf = NULL;
660 telnet->sb_size = 0;
661 telnet->frontend = frontend_handle;
662 telnet->term_width = cfg.width;
663 telnet->term_height = cfg.height;
664 telnet->state = TOP_LEVEL;
665 *backend_handle = telnet;
666
667 /*
668 * Try to find host.
669 */
670 {
671 char buf[200];
672 sprintf(buf, "Looking up host \"%.170s\"", host);
673 logevent(telnet->frontend, buf);
674 }
675 addr = sk_namelookup(host, realhost);
676 if ((err = sk_addr_error(addr)))
677 return err;
678
679 if (port < 0)
680 port = 23; /* default telnet port */
681
682 /*
683 * Open socket.
684 */
685 {
686 char buf[200], addrbuf[100];
687 sk_getaddr(addr, addrbuf, 100);
688 sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
689 logevent(telnet->frontend, buf);
690 }
691 telnet->s = new_connection(addr, *realhost, port, 0, 1,
692 nodelay, (Plug) telnet);
693 if ((err = sk_socket_error(telnet->s)))
694 return err;
695
696 sk_addr_free(addr);
697
698 /*
699 * Initialise option states.
700 */
701 if (cfg.passive_telnet) {
702 const struct Opt *const *o;
703
704 for (o = opts; *o; o++)
705 telnet->opt_states[(*o)->index] = INACTIVE;
706 } else {
707 const struct Opt *const *o;
708
709 for (o = opts; *o; o++) {
710 telnet->opt_states[(*o)->index] = (*o)->initial_state;
711 if (telnet->opt_states[(*o)->index] == REQUESTED)
712 send_opt(telnet, (*o)->send, (*o)->option);
713 }
714 telnet->activated = TRUE;
715 }
716
717 /*
718 * Set up SYNCH state.
719 */
720 telnet->in_synch = FALSE;
721
722 return NULL;
723 }
724
725 /*
726 * Called to send data down the Telnet connection.
727 */
728 static int telnet_send(void *handle, char *buf, int len)
729 {
730 Telnet telnet = (Telnet) handle;
731 char *p;
732 static unsigned char iac[2] = { IAC, IAC };
733 static unsigned char cr[2] = { CR, NUL };
734 #if 0
735 static unsigned char nl[2] = { CR, LF };
736 #endif
737
738 if (telnet->s == NULL)
739 return 0;
740
741 p = buf;
742 while (p < buf + len) {
743 char *q = p;
744
745 while (p < buf + len && iswritable((unsigned char) *p))
746 p++;
747 telnet->bufsize = sk_write(telnet->s, q, p - q);
748
749 while (p < buf + len && !iswritable((unsigned char) *p)) {
750 telnet->bufsize =
751 sk_write(telnet->s, (unsigned char) *p == IAC ? iac : cr, 2);
752 p++;
753 }
754 }
755
756 return telnet->bufsize;
757 }
758
759 /*
760 * Called to query the current socket sendability status.
761 */
762 static int telnet_sendbuffer(void *handle)
763 {
764 Telnet telnet = (Telnet) handle;
765 return telnet->bufsize;
766 }
767
768 /*
769 * Called to set the size of the window from Telnet's POV.
770 */
771 static void telnet_size(void *handle, int width, int height)
772 {
773 Telnet telnet = (Telnet) handle;
774 unsigned char b[16];
775 char logbuf[50];
776
777 telnet->term_width = width;
778 telnet->term_height = height;
779
780 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
781 return;
782 b[0] = IAC;
783 b[1] = SB;
784 b[2] = TELOPT_NAWS;
785 b[3] = telnet->term_width >> 8;
786 b[4] = telnet->term_width & 0xFF;
787 b[5] = telnet->term_height >> 8;
788 b[6] = telnet->term_height & 0xFF;
789 b[7] = IAC;
790 b[8] = SE;
791 telnet->bufsize = sk_write(telnet->s, b, 9);
792 sprintf(logbuf, "client:\tSB NAWS %d,%d",
793 ((unsigned char) b[3] << 8) + (unsigned char) b[4],
794 ((unsigned char) b[5] << 8) + (unsigned char) b[6]);
795 logevent(telnet->frontend, logbuf);
796 }
797
798 /*
799 * Send Telnet special codes.
800 */
801 static void telnet_special(void *handle, Telnet_Special code)
802 {
803 Telnet telnet = (Telnet) handle;
804 unsigned char b[2];
805
806 if (telnet->s == NULL)
807 return;
808
809 b[0] = IAC;
810 switch (code) {
811 case TS_AYT:
812 b[1] = AYT;
813 telnet->bufsize = sk_write(telnet->s, b, 2);
814 break;
815 case TS_BRK:
816 b[1] = BREAK;
817 telnet->bufsize = sk_write(telnet->s, b, 2);
818 break;
819 case TS_EC:
820 b[1] = EC;
821 telnet->bufsize = sk_write(telnet->s, b, 2);
822 break;
823 case TS_EL:
824 b[1] = EL;
825 telnet->bufsize = sk_write(telnet->s, b, 2);
826 break;
827 case TS_GA:
828 b[1] = GA;
829 telnet->bufsize = sk_write(telnet->s, b, 2);
830 break;
831 case TS_NOP:
832 b[1] = NOP;
833 telnet->bufsize = sk_write(telnet->s, b, 2);
834 break;
835 case TS_ABORT:
836 b[1] = ABORT;
837 telnet->bufsize = sk_write(telnet->s, b, 2);
838 break;
839 case TS_AO:
840 b[1] = AO;
841 telnet->bufsize = sk_write(telnet->s, b, 2);
842 break;
843 case TS_IP:
844 b[1] = IP;
845 telnet->bufsize = sk_write(telnet->s, b, 2);
846 break;
847 case TS_SUSP:
848 b[1] = SUSP;
849 telnet->bufsize = sk_write(telnet->s, b, 2);
850 break;
851 case TS_EOR:
852 b[1] = EOR;
853 telnet->bufsize = sk_write(telnet->s, b, 2);
854 break;
855 case TS_EOF:
856 b[1] = xEOF;
857 telnet->bufsize = sk_write(telnet->s, b, 2);
858 break;
859 case TS_EOL:
860 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
861 break;
862 case TS_SYNCH:
863 b[1] = DM;
864 telnet->bufsize = sk_write(telnet->s, b, 1);
865 telnet->bufsize = sk_write_oob(telnet->s, b + 1, 1);
866 break;
867 case TS_RECHO:
868 if (telnet->opt_states[o_echo.index] == INACTIVE ||
869 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
870 telnet->opt_states[o_echo.index] = REQUESTED;
871 send_opt(telnet, o_echo.send, o_echo.option);
872 }
873 break;
874 case TS_LECHO:
875 if (telnet->opt_states[o_echo.index] == ACTIVE) {
876 telnet->opt_states[o_echo.index] = REQUESTED;
877 send_opt(telnet, o_echo.nsend, o_echo.option);
878 }
879 break;
880 case TS_PING:
881 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
882 b[1] = NOP;
883 telnet->bufsize = sk_write(telnet->s, b, 2);
884 }
885 break;
886 }
887 }
888
889 static Socket telnet_socket(void *handle)
890 {
891 Telnet telnet = (Telnet) handle;
892 return telnet->s;
893 }
894
895 static int telnet_sendok(void *handle)
896 {
897 /* Telnet telnet = (Telnet) handle; */
898 return 1;
899 }
900
901 static void telnet_unthrottle(void *handle, int backlog)
902 {
903 Telnet telnet = (Telnet) handle;
904 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
905 }
906
907 static int telnet_ldisc(void *handle, int option)
908 {
909 Telnet telnet = (Telnet) handle;
910 if (option == LD_ECHO)
911 return telnet->echoing;
912 if (option == LD_EDIT)
913 return telnet->editing;
914 return FALSE;
915 }
916
917 static void telnet_provide_ldisc(void *handle, void *ldisc)
918 {
919 Telnet telnet = (Telnet) handle;
920 telnet->ldisc = ldisc;
921 }
922
923 static void telnet_provide_logctx(void *handle, void *logctx)
924 {
925 /* This is a stub. */
926 }
927
928 static int telnet_exitcode(void *handle)
929 {
930 /* Telnet telnet = (Telnet) handle; */
931 /* Telnet doesn't transmit exit codes back to the client */
932 return 0;
933 }
934
935 Backend telnet_backend = {
936 telnet_init,
937 telnet_send,
938 telnet_sendbuffer,
939 telnet_size,
940 telnet_special,
941 telnet_socket,
942 telnet_exitcode,
943 telnet_sendok,
944 telnet_ldisc,
945 telnet_provide_ldisc,
946 telnet_provide_logctx,
947 telnet_unthrottle,
948 23
949 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator