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Add the ability to close sessions. This adds *_free() functions to most
[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) \
90 ( (x) != IAC && \
91 (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))
92
93 static char *telopt(int opt)
94 {
95 #define i(x) if (opt == TELOPT_ ## x) return #x;
96 i(BINARY);
97 i(ECHO);
98 i(RCP);
99 i(SGA);
100 i(NAMS);
101 i(STATUS);
102 i(TM);
103 i(RCTE);
104 i(NAOL);
105 i(NAOP);
106 i(NAOCRD);
107 i(NAOHTS);
108 i(NAOHTD);
109 i(NAOFFD);
110 i(NAOVTS);
111 i(NAOVTD);
112 i(NAOLFD);
113 i(XASCII);
114 i(LOGOUT);
115 i(BM);
116 i(DET);
117 i(SUPDUP);
118 i(SUPDUPOUTPUT);
119 i(SNDLOC);
120 i(TTYPE);
121 i(EOR);
122 i(TUID);
123 i(OUTMRK);
124 i(TTYLOC);
125 i(X3PAD);
126 i(NAWS);
127 i(TSPEED);
128 i(LFLOW);
129 i(LINEMODE);
130 i(XDISPLOC);
131 i(OLD_ENVIRON);
132 i(AUTHENTICATION);
133 i(ENCRYPT);
134 i(NEW_ENVIRON);
135 i(EXOPL);
136 #undef i
137 return "<unknown>";
138 }
139
140 static void telnet_size(void *handle, int width, int height);
141
142 struct Opt {
143 int send; /* what we initially send */
144 int nsend; /* -ve send if requested to stop it */
145 int ack, nak; /* +ve and -ve acknowledgements */
146 int option; /* the option code */
147 int index; /* index into telnet->opt_states[] */
148 enum {
149 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
150 } initial_state;
151 };
152
153 enum {
154 OPTINDEX_NAWS,
155 OPTINDEX_TSPEED,
156 OPTINDEX_TTYPE,
157 OPTINDEX_OENV,
158 OPTINDEX_NENV,
159 OPTINDEX_ECHO,
160 OPTINDEX_WE_SGA,
161 OPTINDEX_THEY_SGA,
162 OPTINDEX_WE_BIN,
163 OPTINDEX_THEY_BIN,
164 NUM_OPTS
165 };
166
167 static const struct Opt o_naws =
168 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
169 static const struct Opt o_tspeed =
170 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
171 static const struct Opt o_ttype =
172 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
173 static const struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
174 OPTINDEX_OENV, INACTIVE
175 };
176 static const struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
177 OPTINDEX_NENV, REQUESTED
178 };
179 static const struct Opt o_echo =
180 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
181 static const struct Opt o_we_sga =
182 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
183 static const struct Opt o_they_sga =
184 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
185 static const struct Opt o_we_bin =
186 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };
187 static const struct Opt o_they_bin =
188 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };
189
190 static const struct Opt *const opts[] = {
191 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
192 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL
193 };
194
195 typedef struct telnet_tag {
196 const struct plug_function_table *fn;
197 /* the above field _must_ be first in the structure */
198
199 Socket s;
200
201 void *frontend;
202 void *ldisc;
203 int term_width, term_height;
204
205 int opt_states[NUM_OPTS];
206
207 int echoing, editing;
208 int activated;
209 int bufsize;
210 int in_synch;
211 int sb_opt, sb_len;
212 unsigned char *sb_buf;
213 int sb_size;
214
215 enum {
216 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
217 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
218 } state;
219
220 Config cfg;
221 } *Telnet;
222
223 #define TELNET_MAX_BACKLOG 4096
224
225 #define SB_DELTA 1024
226
227 static void c_write1(Telnet telnet, int c)
228 {
229 int backlog;
230 char cc = (char) c;
231 backlog = from_backend(telnet->frontend, 0, &cc, 1);
232 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
233 }
234
235 static void log_option(Telnet telnet, char *sender, int cmd, int option)
236 {
237 char *buf;
238 /*
239 * The strange-looking "<?""?>" below is there to avoid a
240 * trigraph - a double question mark followed by > maps to a
241 * closing brace character!
242 */
243 buf = dupprintf("%s:\t%s %s", sender,
244 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
245 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
246 telopt(option));
247 logevent(telnet->frontend, buf);
248 sfree(buf);
249 }
250
251 static void send_opt(Telnet telnet, int cmd, int option)
252 {
253 unsigned char b[3];
254
255 b[0] = IAC;
256 b[1] = cmd;
257 b[2] = option;
258 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);
259 log_option(telnet, "client", cmd, option);
260 }
261
262 static void deactivate_option(Telnet telnet, const struct Opt *o)
263 {
264 if (telnet->opt_states[o->index] == REQUESTED ||
265 telnet->opt_states[o->index] == ACTIVE)
266 send_opt(telnet, o->nsend, o->option);
267 telnet->opt_states[o->index] = REALLY_INACTIVE;
268 }
269
270 /*
271 * Generate side effects of enabling or disabling an option.
272 */
273 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
274 {
275 if (o->option == TELOPT_ECHO && o->send == DO)
276 telnet->echoing = !enabled;
277 else if (o->option == TELOPT_SGA && o->send == DO)
278 telnet->editing = !enabled;
279 if (telnet->ldisc) /* cause ldisc to notice the change */
280 ldisc_send(telnet->ldisc, NULL, 0, 0);
281
282 /* Ensure we get the minimum options */
283 if (!telnet->activated) {
284 if (telnet->opt_states[o_echo.index] == INACTIVE) {
285 telnet->opt_states[o_echo.index] = REQUESTED;
286 send_opt(telnet, o_echo.send, o_echo.option);
287 }
288 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
289 telnet->opt_states[o_we_sga.index] = REQUESTED;
290 send_opt(telnet, o_we_sga.send, o_we_sga.option);
291 }
292 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
293 telnet->opt_states[o_they_sga.index] = REQUESTED;
294 send_opt(telnet, o_they_sga.send, o_they_sga.option);
295 }
296 telnet->activated = TRUE;
297 }
298 }
299
300 static void activate_option(Telnet telnet, const struct Opt *o)
301 {
302 if (o->send == WILL && o->option == TELOPT_NAWS)
303 telnet_size(telnet, telnet->term_width, telnet->term_height);
304 if (o->send == WILL &&
305 (o->option == TELOPT_NEW_ENVIRON ||
306 o->option == TELOPT_OLD_ENVIRON)) {
307 /*
308 * We may only have one kind of ENVIRON going at a time.
309 * This is a hack, but who cares.
310 */
311 deactivate_option(telnet, o->option ==
312 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
313 }
314 option_side_effects(telnet, o, 1);
315 }
316
317 static void refused_option(Telnet telnet, const struct Opt *o)
318 {
319 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
320 telnet->opt_states[o_oenv.index] == INACTIVE) {
321 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
322 telnet->opt_states[o_oenv.index] = REQUESTED;
323 }
324 option_side_effects(telnet, o, 0);
325 }
326
327 static void proc_rec_opt(Telnet telnet, int cmd, int option)
328 {
329 const struct Opt *const *o;
330
331 log_option(telnet, "server", cmd, option);
332 for (o = opts; *o; o++) {
333 if ((*o)->option == option && (*o)->ack == cmd) {
334 switch (telnet->opt_states[(*o)->index]) {
335 case REQUESTED:
336 telnet->opt_states[(*o)->index] = ACTIVE;
337 activate_option(telnet, *o);
338 break;
339 case ACTIVE:
340 break;
341 case INACTIVE:
342 telnet->opt_states[(*o)->index] = ACTIVE;
343 send_opt(telnet, (*o)->send, option);
344 activate_option(telnet, *o);
345 break;
346 case REALLY_INACTIVE:
347 send_opt(telnet, (*o)->nsend, option);
348 break;
349 }
350 return;
351 } else if ((*o)->option == option && (*o)->nak == cmd) {
352 switch (telnet->opt_states[(*o)->index]) {
353 case REQUESTED:
354 telnet->opt_states[(*o)->index] = INACTIVE;
355 refused_option(telnet, *o);
356 break;
357 case ACTIVE:
358 telnet->opt_states[(*o)->index] = INACTIVE;
359 send_opt(telnet, (*o)->nsend, option);
360 option_side_effects(telnet, *o, 0);
361 break;
362 case INACTIVE:
363 case REALLY_INACTIVE:
364 break;
365 }
366 return;
367 }
368 }
369 /*
370 * If we reach here, the option was one we weren't prepared to
371 * cope with. So send a negative ack.
372 */
373 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
374 }
375
376 static void process_subneg(Telnet telnet)
377 {
378 unsigned char b[2048], *p, *q;
379 int var, value, n;
380 char *e;
381
382 switch (telnet->sb_opt) {
383 case TELOPT_TSPEED:
384 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
385 char *logbuf;
386 b[0] = IAC;
387 b[1] = SB;
388 b[2] = TELOPT_TSPEED;
389 b[3] = TELQUAL_IS;
390 strcpy((char *)(b + 4), telnet->cfg.termspeed);
391 n = 4 + strlen(telnet->cfg.termspeed);
392 b[n] = IAC;
393 b[n + 1] = SE;
394 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
395 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
396 logbuf = dupprintf("client:\tSB TSPEED IS %s", telnet->cfg.termspeed);
397 logevent(telnet->frontend, logbuf);
398 sfree(logbuf);
399 } else
400 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
401 break;
402 case TELOPT_TTYPE:
403 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
404 char *logbuf;
405 b[0] = IAC;
406 b[1] = SB;
407 b[2] = TELOPT_TTYPE;
408 b[3] = TELQUAL_IS;
409 for (n = 0; telnet->cfg.termtype[n]; n++)
410 b[n + 4] = (telnet->cfg.termtype[n] >= 'a'
411 && telnet->cfg.termtype[n] <=
412 'z' ? telnet->cfg.termtype[n] + 'A' -
413 'a' : telnet->cfg.termtype[n]);
414 b[n + 4] = IAC;
415 b[n + 5] = SE;
416 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);
417 b[n + 4] = 0;
418 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
419 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
420 logevent(telnet->frontend, logbuf);
421 sfree(logbuf);
422 } else
423 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
424 break;
425 case TELOPT_OLD_ENVIRON:
426 case TELOPT_NEW_ENVIRON:
427 p = telnet->sb_buf;
428 q = p + telnet->sb_len;
429 if (p < q && *p == TELQUAL_SEND) {
430 char *logbuf;
431 p++;
432 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
433 logevent(telnet->frontend, logbuf);
434 sfree(logbuf);
435 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
436 if (telnet->cfg.rfc_environ) {
437 value = RFC_VALUE;
438 var = RFC_VAR;
439 } else {
440 value = BSD_VALUE;
441 var = BSD_VAR;
442 }
443 /*
444 * Try to guess the sense of VAR and VALUE.
445 */
446 while (p < q) {
447 if (*p == RFC_VAR) {
448 value = RFC_VALUE;
449 var = RFC_VAR;
450 } else if (*p == BSD_VAR) {
451 value = BSD_VALUE;
452 var = BSD_VAR;
453 }
454 p++;
455 }
456 } else {
457 /*
458 * With NEW_ENVIRON, the sense of VAR and VALUE
459 * isn't in doubt.
460 */
461 value = RFC_VALUE;
462 var = RFC_VAR;
463 }
464 b[0] = IAC;
465 b[1] = SB;
466 b[2] = telnet->sb_opt;
467 b[3] = TELQUAL_IS;
468 n = 4;
469 e = telnet->cfg.environmt;
470 while (*e) {
471 b[n++] = var;
472 while (*e && *e != '\t')
473 b[n++] = *e++;
474 if (*e == '\t')
475 e++;
476 b[n++] = value;
477 while (*e)
478 b[n++] = *e++;
479 e++;
480 }
481 if (*telnet->cfg.username) {
482 b[n++] = var;
483 b[n++] = 'U';
484 b[n++] = 'S';
485 b[n++] = 'E';
486 b[n++] = 'R';
487 b[n++] = value;
488 e = telnet->cfg.username;
489 while (*e)
490 b[n++] = *e++;
491 }
492 b[n++] = IAC;
493 b[n++] = SE;
494 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
495 logbuf = dupprintf("client:\tSB %s IS %s", telopt(telnet->sb_opt),
496 n == 6 ? "<nothing>" : "<stuff>");
497 logevent(telnet->frontend, logbuf);
498 sfree(logbuf);
499 }
500 break;
501 }
502 }
503
504 static void do_telnet_read(Telnet telnet, char *buf, int len)
505 {
506
507 while (len--) {
508 int c = (unsigned char) *buf++;
509
510 switch (telnet->state) {
511 case TOP_LEVEL:
512 case SEENCR:
513 if (c == NUL && telnet->state == SEENCR)
514 telnet->state = TOP_LEVEL;
515 else if (c == IAC)
516 telnet->state = SEENIAC;
517 else {
518 if (!telnet->in_synch)
519 c_write1(telnet, c);
520
521 #if 1
522 /* I can't get the F***ing winsock to insert the urgent IAC
523 * into the right position! Even with SO_OOBINLINE it gives
524 * it to recv too soon. And of course the DM byte (that
525 * arrives in the same packet!) appears several K later!!
526 *
527 * Oh well, we do get the DM in the right place so I'll
528 * just stop hiding on the next 0xf2 and hope for the best.
529 */
530 else if (c == DM)
531 telnet->in_synch = 0;
532 #endif
533 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)
534 telnet->state = SEENCR;
535 else
536 telnet->state = TOP_LEVEL;
537 }
538 break;
539 case SEENIAC:
540 if (c == DO)
541 telnet->state = SEENDO;
542 else if (c == DONT)
543 telnet->state = SEENDONT;
544 else if (c == WILL)
545 telnet->state = SEENWILL;
546 else if (c == WONT)
547 telnet->state = SEENWONT;
548 else if (c == SB)
549 telnet->state = SEENSB;
550 else if (c == DM) {
551 telnet->in_synch = 0;
552 telnet->state = TOP_LEVEL;
553 } else {
554 /* ignore everything else; print it if it's IAC */
555 if (c == IAC) {
556 c_write1(telnet, c);
557 }
558 telnet->state = TOP_LEVEL;
559 }
560 break;
561 case SEENWILL:
562 proc_rec_opt(telnet, WILL, c);
563 telnet->state = TOP_LEVEL;
564 break;
565 case SEENWONT:
566 proc_rec_opt(telnet, WONT, c);
567 telnet->state = TOP_LEVEL;
568 break;
569 case SEENDO:
570 proc_rec_opt(telnet, DO, c);
571 telnet->state = TOP_LEVEL;
572 break;
573 case SEENDONT:
574 proc_rec_opt(telnet, DONT, c);
575 telnet->state = TOP_LEVEL;
576 break;
577 case SEENSB:
578 telnet->sb_opt = c;
579 telnet->sb_len = 0;
580 telnet->state = SUBNEGOT;
581 break;
582 case SUBNEGOT:
583 if (c == IAC)
584 telnet->state = SUBNEG_IAC;
585 else {
586 subneg_addchar:
587 if (telnet->sb_len >= telnet->sb_size) {
588 unsigned char *newbuf;
589 telnet->sb_size += SB_DELTA;
590 newbuf = (telnet->sb_buf ?
591 srealloc(telnet->sb_buf, telnet->sb_size) :
592 smalloc(telnet->sb_size));
593 if (newbuf)
594 telnet->sb_buf = newbuf;
595 else
596 telnet->sb_size -= SB_DELTA;
597 }
598 if (telnet->sb_len < telnet->sb_size)
599 telnet->sb_buf[telnet->sb_len++] = c;
600 telnet->state = SUBNEGOT; /* in case we came here by goto */
601 }
602 break;
603 case SUBNEG_IAC:
604 if (c != SE)
605 goto subneg_addchar; /* yes, it's a hack, I know, but... */
606 else {
607 process_subneg(telnet);
608 telnet->state = TOP_LEVEL;
609 }
610 break;
611 }
612 }
613 }
614
615 static int telnet_closing(Plug plug, char *error_msg, int error_code,
616 int calling_back)
617 {
618 Telnet telnet = (Telnet) plug;
619
620 if (telnet->s) {
621 sk_close(telnet->s);
622 telnet->s = NULL;
623 }
624 if (error_msg) {
625 /* A socket error has occurred. */
626 logevent(telnet->frontend, error_msg);
627 connection_fatal("%s", error_msg);
628 } /* Otherwise, the remote side closed the connection normally. */
629 return 0;
630 }
631
632 static int telnet_receive(Plug plug, int urgent, char *data, int len)
633 {
634 Telnet telnet = (Telnet) plug;
635 if (urgent)
636 telnet->in_synch = TRUE;
637 do_telnet_read(telnet, data, len);
638 return 1;
639 }
640
641 static void telnet_sent(Plug plug, int bufsize)
642 {
643 Telnet telnet = (Telnet) plug;
644 telnet->bufsize = bufsize;
645 }
646
647 /*
648 * Called to set up the Telnet connection.
649 *
650 * Returns an error message, or NULL on success.
651 *
652 * Also places the canonical host name into `realhost'. It must be
653 * freed by the caller.
654 */
655 static char *telnet_init(void *frontend_handle, void **backend_handle,
656 Config *cfg,
657 char *host, int port, char **realhost, int nodelay)
658 {
659 static const struct plug_function_table fn_table = {
660 telnet_closing,
661 telnet_receive,
662 telnet_sent
663 };
664 SockAddr addr;
665 char *err;
666 Telnet telnet;
667
668 telnet = smalloc(sizeof(*telnet));
669 telnet->fn = &fn_table;
670 telnet->cfg = *cfg; /* STRUCTURE COPY */
671 telnet->s = NULL;
672 telnet->echoing = TRUE;
673 telnet->editing = TRUE;
674 telnet->activated = FALSE;
675 telnet->sb_buf = NULL;
676 telnet->sb_size = 0;
677 telnet->frontend = frontend_handle;
678 telnet->term_width = telnet->cfg.width;
679 telnet->term_height = telnet->cfg.height;
680 telnet->state = TOP_LEVEL;
681 *backend_handle = telnet;
682
683 /*
684 * Try to find host.
685 */
686 {
687 char *buf;
688 buf = dupprintf("Looking up host \"%s\"", host);
689 logevent(telnet->frontend, buf);
690 sfree(buf);
691 }
692 addr = name_lookup(host, port, realhost, &telnet->cfg);
693 if ((err = sk_addr_error(addr)) != NULL)
694 return err;
695
696 if (port < 0)
697 port = 23; /* default telnet port */
698
699 /*
700 * Open socket.
701 */
702 {
703 char *buf, addrbuf[100];
704 sk_getaddr(addr, addrbuf, 100);
705 buf = dupprintf("Connecting to %s port %d", addrbuf, port);
706 logevent(telnet->frontend, buf);
707 sfree(buf);
708 }
709 telnet->s = new_connection(addr, *realhost, port, 0, 1,
710 nodelay, (Plug) telnet, &telnet->cfg);
711 if ((err = sk_socket_error(telnet->s)) != NULL)
712 return err;
713
714 sk_addr_free(addr);
715
716 /*
717 * Initialise option states.
718 */
719 if (telnet->cfg.passive_telnet) {
720 const struct Opt *const *o;
721
722 for (o = opts; *o; o++)
723 telnet->opt_states[(*o)->index] = INACTIVE;
724 } else {
725 const struct Opt *const *o;
726
727 for (o = opts; *o; o++) {
728 telnet->opt_states[(*o)->index] = (*o)->initial_state;
729 if (telnet->opt_states[(*o)->index] == REQUESTED)
730 send_opt(telnet, (*o)->send, (*o)->option);
731 }
732 telnet->activated = TRUE;
733 }
734
735 /*
736 * Set up SYNCH state.
737 */
738 telnet->in_synch = FALSE;
739
740 return NULL;
741 }
742
743 static void telnet_free(void *handle)
744 {
745 Telnet telnet = (Telnet) handle;
746
747 sfree(telnet->sb_buf);
748 if (telnet->s)
749 sk_close(telnet->s);
750 sfree(telnet);
751 }
752 /*
753 * Reconfigure the Telnet backend. There's no immediate action
754 * necessary, in this backend: we just save the fresh config for
755 * any subsequent negotiations.
756 */
757 static void telnet_reconfig(void *handle, Config *cfg)
758 {
759 Telnet telnet = (Telnet) handle;
760 telnet->cfg = *cfg; /* STRUCTURE COPY */
761 }
762
763 /*
764 * Called to send data down the Telnet connection.
765 */
766 static int telnet_send(void *handle, char *buf, int len)
767 {
768 Telnet telnet = (Telnet) handle;
769 unsigned char *p, *end;
770 static const unsigned char iac[2] = { IAC, IAC };
771 static const unsigned char cr[2] = { CR, NUL };
772 #if 0
773 static const unsigned char nl[2] = { CR, LF };
774 #endif
775
776 if (telnet->s == NULL)
777 return 0;
778
779 p = (unsigned char *)buf;
780 end = (unsigned char *)(buf + len);
781 while (p < end) {
782 unsigned char *q = p;
783
784 while (p < end && iswritable(*p))
785 p++;
786 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
787
788 while (p < end && !iswritable(*p)) {
789 telnet->bufsize =
790 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
791 p++;
792 }
793 }
794
795 return telnet->bufsize;
796 }
797
798 /*
799 * Called to query the current socket sendability status.
800 */
801 static int telnet_sendbuffer(void *handle)
802 {
803 Telnet telnet = (Telnet) handle;
804 return telnet->bufsize;
805 }
806
807 /*
808 * Called to set the size of the window from Telnet's POV.
809 */
810 static void telnet_size(void *handle, int width, int height)
811 {
812 Telnet telnet = (Telnet) handle;
813 unsigned char b[24];
814 int n;
815 char *logbuf;
816
817 telnet->term_width = width;
818 telnet->term_height = height;
819
820 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
821 return;
822 n = 0;
823 b[n++] = IAC;
824 b[n++] = SB;
825 b[n++] = TELOPT_NAWS;
826 b[n++] = telnet->term_width >> 8;
827 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
828 b[n++] = telnet->term_width & 0xFF;
829 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
830 b[n++] = telnet->term_height >> 8;
831 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
832 b[n++] = telnet->term_height & 0xFF;
833 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
834 b[n++] = IAC;
835 b[n++] = SE;
836 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
837 logbuf = dupprintf("client:\tSB NAWS %d,%d",
838 telnet->term_width, telnet->term_height);
839 logevent(telnet->frontend, logbuf);
840 sfree(logbuf);
841 }
842
843 /*
844 * Send Telnet special codes.
845 */
846 static void telnet_special(void *handle, Telnet_Special code)
847 {
848 Telnet telnet = (Telnet) handle;
849 unsigned char b[2];
850
851 if (telnet->s == NULL)
852 return;
853
854 b[0] = IAC;
855 switch (code) {
856 case TS_AYT:
857 b[1] = AYT;
858 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
859 break;
860 case TS_BRK:
861 b[1] = BREAK;
862 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
863 break;
864 case TS_EC:
865 b[1] = EC;
866 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
867 break;
868 case TS_EL:
869 b[1] = EL;
870 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
871 break;
872 case TS_GA:
873 b[1] = GA;
874 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
875 break;
876 case TS_NOP:
877 b[1] = NOP;
878 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
879 break;
880 case TS_ABORT:
881 b[1] = ABORT;
882 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
883 break;
884 case TS_AO:
885 b[1] = AO;
886 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
887 break;
888 case TS_IP:
889 b[1] = IP;
890 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
891 break;
892 case TS_SUSP:
893 b[1] = SUSP;
894 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
895 break;
896 case TS_EOR:
897 b[1] = EOR;
898 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
899 break;
900 case TS_EOF:
901 b[1] = xEOF;
902 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
903 break;
904 case TS_EOL:
905 /* In BINARY mode, CR-LF becomes just CR. */
906 if (telnet->opt_states[o_we_bin.index] == ACTIVE)
907 telnet->bufsize = sk_write(telnet->s, "\r", 2);
908 else
909 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
910 break;
911 case TS_SYNCH:
912 b[1] = DM;
913 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
914 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
915 break;
916 case TS_RECHO:
917 if (telnet->opt_states[o_echo.index] == INACTIVE ||
918 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
919 telnet->opt_states[o_echo.index] = REQUESTED;
920 send_opt(telnet, o_echo.send, o_echo.option);
921 }
922 break;
923 case TS_LECHO:
924 if (telnet->opt_states[o_echo.index] == ACTIVE) {
925 telnet->opt_states[o_echo.index] = REQUESTED;
926 send_opt(telnet, o_echo.nsend, o_echo.option);
927 }
928 break;
929 case TS_PING:
930 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
931 b[1] = NOP;
932 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
933 }
934 break;
935 }
936 }
937
938 static Socket telnet_socket(void *handle)
939 {
940 Telnet telnet = (Telnet) handle;
941 return telnet->s;
942 }
943
944 static int telnet_sendok(void *handle)
945 {
946 /* Telnet telnet = (Telnet) handle; */
947 return 1;
948 }
949
950 static void telnet_unthrottle(void *handle, int backlog)
951 {
952 Telnet telnet = (Telnet) handle;
953 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
954 }
955
956 static int telnet_ldisc(void *handle, int option)
957 {
958 Telnet telnet = (Telnet) handle;
959 if (option == LD_ECHO)
960 return telnet->echoing;
961 if (option == LD_EDIT)
962 return telnet->editing;
963 return FALSE;
964 }
965
966 static void telnet_provide_ldisc(void *handle, void *ldisc)
967 {
968 Telnet telnet = (Telnet) handle;
969 telnet->ldisc = ldisc;
970 }
971
972 static void telnet_provide_logctx(void *handle, void *logctx)
973 {
974 /* This is a stub. */
975 }
976
977 static int telnet_exitcode(void *handle)
978 {
979 /* Telnet telnet = (Telnet) handle; */
980 /* Telnet doesn't transmit exit codes back to the client */
981 return 0;
982 }
983
984 Backend telnet_backend = {
985 telnet_init,
986 telnet_free,
987 telnet_reconfig,
988 telnet_send,
989 telnet_sendbuffer,
990 telnet_size,
991 telnet_special,
992 telnet_socket,
993 telnet_exitcode,
994 telnet_sendok,
995 telnet_ldisc,
996 telnet_provide_ldisc,
997 telnet_provide_logctx,
998 telnet_unthrottle,
999 23
1000 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator