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[u/mdw/putty] / telnet.c
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374330e2 1#include <stdio.h>
2#include <stdlib.h>
374330e2 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
32874aea 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 */
347e5401 75#define TELOPT_TN3270E 40 /* TN3270 enhancements */
76#define TELOPT_XAUTH 41
77#define TELOPT_CHARSET 42 /* Character set */
78#define TELOPT_RSP 43 /* Remote serial port */
79#define TELOPT_COM_PORT_OPTION 44 /* Com port control */
80#define TELOPT_SLE 45 /* Suppress local echo */
81#define TELOPT_STARTTLS 46 /* Start TLS */
82#define TELOPT_KERMIT 47 /* Automatic Kermit file transfer */
83#define TELOPT_SEND_URL 48
84#define TELOPT_FORWARD_X 49
85#define TELOPT_PRAGMA_LOGON 138
86#define TELOPT_SSPI_LOGON 139
87#define TELOPT_PRAGMA_HEARTBEAT 140
32874aea 88#define TELOPT_EXOPL 255 /* extended-options-list */
89
90#define TELQUAL_IS 0 /* option is... */
91#define TELQUAL_SEND 1 /* send option */
92#define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
374330e2 93#define BSD_VAR 1
94#define BSD_VALUE 0
95#define RFC_VAR 0
96#define RFC_VALUE 1
97
98#define CR 13
99#define LF 10
100#define NUL 0
101
656fa244 102#define iswritable(x) \
103 ( (x) != IAC && \
104 (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))
374330e2 105
32874aea 106static char *telopt(int opt)
107{
374330e2 108#define i(x) if (opt == TELOPT_ ## x) return #x;
32874aea 109 i(BINARY);
110 i(ECHO);
111 i(RCP);
112 i(SGA);
113 i(NAMS);
114 i(STATUS);
115 i(TM);
116 i(RCTE);
117 i(NAOL);
118 i(NAOP);
119 i(NAOCRD);
120 i(NAOHTS);
121 i(NAOHTD);
122 i(NAOFFD);
123 i(NAOVTS);
124 i(NAOVTD);
125 i(NAOLFD);
126 i(XASCII);
127 i(LOGOUT);
128 i(BM);
129 i(DET);
130 i(SUPDUP);
131 i(SUPDUPOUTPUT);
132 i(SNDLOC);
133 i(TTYPE);
134 i(EOR);
135 i(TUID);
136 i(OUTMRK);
137 i(TTYLOC);
138 i(X3PAD);
139 i(NAWS);
140 i(TSPEED);
141 i(LFLOW);
142 i(LINEMODE);
143 i(XDISPLOC);
144 i(OLD_ENVIRON);
145 i(AUTHENTICATION);
146 i(ENCRYPT);
147 i(NEW_ENVIRON);
347e5401 148 i(TN3270E);
149 i(XAUTH);
150 i(CHARSET);
151 i(RSP);
152 i(COM_PORT_OPTION);
153 i(SLE);
154 i(STARTTLS);
155 i(KERMIT);
156 i(SEND_URL);
157 i(FORWARD_X);
158 i(PRAGMA_LOGON);
159 i(SSPI_LOGON);
160 i(PRAGMA_HEARTBEAT);
32874aea 161 i(EXOPL);
374330e2 162#undef i
163 return "<unknown>";
164}
165
51470298 166static void telnet_size(void *handle, int width, int height);
374330e2 167
168struct Opt {
169 int send; /* what we initially send */
170 int nsend; /* -ve send if requested to stop it */
171 int ack, nak; /* +ve and -ve acknowledgements */
172 int option; /* the option code */
51470298 173 int index; /* index into telnet->opt_states[] */
374330e2 174 enum {
175 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
51470298 176 } initial_state;
177};
178
179enum {
180 OPTINDEX_NAWS,
181 OPTINDEX_TSPEED,
182 OPTINDEX_TTYPE,
183 OPTINDEX_OENV,
184 OPTINDEX_NENV,
185 OPTINDEX_ECHO,
186 OPTINDEX_WE_SGA,
187 OPTINDEX_THEY_SGA,
656fa244 188 OPTINDEX_WE_BIN,
189 OPTINDEX_THEY_BIN,
51470298 190 NUM_OPTS
374330e2 191};
192
51470298 193static const struct Opt o_naws =
194 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
195static const struct Opt o_tspeed =
196 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
197static const struct Opt o_ttype =
198 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
5f95fdf1 199static const struct Opt o_oenv =
200 { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };
201static const struct Opt o_nenv =
202 { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };
51470298 203static const struct Opt o_echo =
204 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
205static const struct Opt o_we_sga =
206 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
207static const struct Opt o_they_sga =
208 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
656fa244 209static const struct Opt o_we_bin =
210 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };
211static const struct Opt o_they_bin =
212 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };
51470298 213
214static const struct Opt *const opts[] = {
374330e2 215 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
656fa244 216 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL
374330e2 217};
218
51470298 219typedef struct telnet_tag {
220 const struct plug_function_table *fn;
221 /* the above field _must_ be first in the structure */
222
223 Socket s;
224
225 void *frontend;
b9d7bcad 226 void *ldisc;
51470298 227 int term_width, term_height;
228
229 int opt_states[NUM_OPTS];
230
231 int echoing, editing;
232 int activated;
233 int bufsize;
234 int in_synch;
235 int sb_opt, sb_len;
a1fd562d 236 unsigned char *sb_buf;
51470298 237 int sb_size;
238
239 enum {
240 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
241 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
242 } state;
243
86916870 244 Config cfg;
39934deb 245
246 Pinger pinger;
51470298 247} *Telnet;
248
5471d09a 249#define TELNET_MAX_BACKLOG 4096
250
374330e2 251#define SB_DELTA 1024
252
51470298 253static void c_write1(Telnet telnet, int c)
32874aea 254{
5471d09a 255 int backlog;
32874aea 256 char cc = (char) c;
51470298 257 backlog = from_backend(telnet->frontend, 0, &cc, 1);
258 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
fe50e814 259}
260
a8327734 261static void log_option(Telnet telnet, char *sender, int cmd, int option)
32874aea 262{
57356d63 263 char *buf;
24d7f854 264 /*
265 * The strange-looking "<?""?>" below is there to avoid a
266 * trigraph - a double question mark followed by > maps to a
267 * closing brace character!
268 */
57356d63 269 buf = dupprintf("%s:\t%s %s", sender,
270 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
271 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
272 telopt(option));
a8327734 273 logevent(telnet->frontend, buf);
57356d63 274 sfree(buf);
374330e2 275}
276
51470298 277static void send_opt(Telnet telnet, int cmd, int option)
32874aea 278{
374330e2 279 unsigned char b[3];
280
32874aea 281 b[0] = IAC;
282 b[1] = cmd;
283 b[2] = option;
a1fd562d 284 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);
a8327734 285 log_option(telnet, "client", cmd, option);
374330e2 286}
287
51470298 288static void deactivate_option(Telnet telnet, const struct Opt *o)
32874aea 289{
51470298 290 if (telnet->opt_states[o->index] == REQUESTED ||
291 telnet->opt_states[o->index] == ACTIVE)
292 send_opt(telnet, o->nsend, o->option);
293 telnet->opt_states[o->index] = REALLY_INACTIVE;
374330e2 294}
295
708bbbbe 296/*
297 * Generate side effects of enabling or disabling an option.
298 */
51470298 299static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
32874aea 300{
0965bee0 301 if (o->option == TELOPT_ECHO && o->send == DO)
51470298 302 telnet->echoing = !enabled;
b6c680d4 303 else if (o->option == TELOPT_SGA && o->send == DO)
51470298 304 telnet->editing = !enabled;
b9d7bcad 305 if (telnet->ldisc) /* cause ldisc to notice the change */
306 ldisc_send(telnet->ldisc, NULL, 0, 0);
8faa456c 307
308 /* Ensure we get the minimum options */
51470298 309 if (!telnet->activated) {
310 if (telnet->opt_states[o_echo.index] == INACTIVE) {
311 telnet->opt_states[o_echo.index] = REQUESTED;
312 send_opt(telnet, o_echo.send, o_echo.option);
8faa456c 313 }
51470298 314 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
315 telnet->opt_states[o_we_sga.index] = REQUESTED;
316 send_opt(telnet, o_we_sga.send, o_we_sga.option);
8faa456c 317 }
51470298 318 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
319 telnet->opt_states[o_they_sga.index] = REQUESTED;
320 send_opt(telnet, o_they_sga.send, o_they_sga.option);
8faa456c 321 }
51470298 322 telnet->activated = TRUE;
8faa456c 323 }
708bbbbe 324}
325
51470298 326static void activate_option(Telnet telnet, const struct Opt *o)
32874aea 327{
374330e2 328 if (o->send == WILL && o->option == TELOPT_NAWS)
51470298 329 telnet_size(telnet, telnet->term_width, telnet->term_height);
374330e2 330 if (o->send == WILL &&
331 (o->option == TELOPT_NEW_ENVIRON ||
332 o->option == TELOPT_OLD_ENVIRON)) {
333 /*
334 * We may only have one kind of ENVIRON going at a time.
335 * This is a hack, but who cares.
336 */
51470298 337 deactivate_option(telnet, o->option ==
32874aea 338 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
374330e2 339 }
51470298 340 option_side_effects(telnet, o, 1);
374330e2 341}
342
51470298 343static void refused_option(Telnet telnet, const struct Opt *o)
32874aea 344{
374330e2 345 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
51470298 346 telnet->opt_states[o_oenv.index] == INACTIVE) {
347 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
348 telnet->opt_states[o_oenv.index] = REQUESTED;
374330e2 349 }
51470298 350 option_side_effects(telnet, o, 0);
374330e2 351}
352
51470298 353static void proc_rec_opt(Telnet telnet, int cmd, int option)
32874aea 354{
51470298 355 const struct Opt *const *o;
374330e2 356
a8327734 357 log_option(telnet, "server", cmd, option);
374330e2 358 for (o = opts; *o; o++) {
359 if ((*o)->option == option && (*o)->ack == cmd) {
51470298 360 switch (telnet->opt_states[(*o)->index]) {
374330e2 361 case REQUESTED:
51470298 362 telnet->opt_states[(*o)->index] = ACTIVE;
363 activate_option(telnet, *o);
374330e2 364 break;
365 case ACTIVE:
366 break;
367 case INACTIVE:
51470298 368 telnet->opt_states[(*o)->index] = ACTIVE;
369 send_opt(telnet, (*o)->send, option);
370 activate_option(telnet, *o);
374330e2 371 break;
372 case REALLY_INACTIVE:
51470298 373 send_opt(telnet, (*o)->nsend, option);
374330e2 374 break;
375 }
376 return;
377 } else if ((*o)->option == option && (*o)->nak == cmd) {
51470298 378 switch (telnet->opt_states[(*o)->index]) {
374330e2 379 case REQUESTED:
51470298 380 telnet->opt_states[(*o)->index] = INACTIVE;
381 refused_option(telnet, *o);
374330e2 382 break;
383 case ACTIVE:
51470298 384 telnet->opt_states[(*o)->index] = INACTIVE;
385 send_opt(telnet, (*o)->nsend, option);
386 option_side_effects(telnet, *o, 0);
374330e2 387 break;
388 case INACTIVE:
389 case REALLY_INACTIVE:
390 break;
391 }
392 return;
393 }
394 }
395 /*
396 * If we reach here, the option was one we weren't prepared to
108b0b94 397 * cope with. If the request was positive (WILL or DO), we send
398 * a negative ack to indicate refusal. If the request was
399 * negative (WONT / DONT), we must do nothing.
374330e2 400 */
108b0b94 401 if (cmd == WILL || cmd == DO)
402 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
374330e2 403}
404
51470298 405static void process_subneg(Telnet telnet)
32874aea 406{
374330e2 407 unsigned char b[2048], *p, *q;
408 int var, value, n;
409 char *e;
410
51470298 411 switch (telnet->sb_opt) {
374330e2 412 case TELOPT_TSPEED:
51470298 413 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
57356d63 414 char *logbuf;
32874aea 415 b[0] = IAC;
416 b[1] = SB;
417 b[2] = TELOPT_TSPEED;
374330e2 418 b[3] = TELQUAL_IS;
86916870 419 strcpy((char *)(b + 4), telnet->cfg.termspeed);
420 n = 4 + strlen(telnet->cfg.termspeed);
32874aea 421 b[n] = IAC;
422 b[n + 1] = SE;
a1fd562d 423 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
a8327734 424 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
86916870 425 logbuf = dupprintf("client:\tSB TSPEED IS %s", telnet->cfg.termspeed);
a8327734 426 logevent(telnet->frontend, logbuf);
57356d63 427 sfree(logbuf);
374330e2 428 } else
a8327734 429 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
374330e2 430 break;
431 case TELOPT_TTYPE:
51470298 432 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
57356d63 433 char *logbuf;
32874aea 434 b[0] = IAC;
435 b[1] = SB;
436 b[2] = TELOPT_TTYPE;
374330e2 437 b[3] = TELQUAL_IS;
86916870 438 for (n = 0; telnet->cfg.termtype[n]; n++)
439 b[n + 4] = (telnet->cfg.termtype[n] >= 'a'
440 && telnet->cfg.termtype[n] <=
441 'z' ? telnet->cfg.termtype[n] + 'A' -
442 'a' : telnet->cfg.termtype[n]);
32874aea 443 b[n + 4] = IAC;
444 b[n + 5] = SE;
a1fd562d 445 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);
32874aea 446 b[n + 4] = 0;
a8327734 447 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
57356d63 448 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
a8327734 449 logevent(telnet->frontend, logbuf);
57356d63 450 sfree(logbuf);
374330e2 451 } else
a8327734 452 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
374330e2 453 break;
454 case TELOPT_OLD_ENVIRON:
32874aea 455 case TELOPT_NEW_ENVIRON:
51470298 456 p = telnet->sb_buf;
457 q = p + telnet->sb_len;
374330e2 458 if (p < q && *p == TELQUAL_SEND) {
57356d63 459 char *logbuf;
374330e2 460 p++;
57356d63 461 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
a8327734 462 logevent(telnet->frontend, logbuf);
57356d63 463 sfree(logbuf);
51470298 464 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
86916870 465 if (telnet->cfg.rfc_environ) {
374330e2 466 value = RFC_VALUE;
467 var = RFC_VAR;
468 } else {
469 value = BSD_VALUE;
470 var = BSD_VAR;
471 }
472 /*
473 * Try to guess the sense of VAR and VALUE.
474 */
475 while (p < q) {
476 if (*p == RFC_VAR) {
477 value = RFC_VALUE;
478 var = RFC_VAR;
479 } else if (*p == BSD_VAR) {
480 value = BSD_VALUE;
481 var = BSD_VAR;
482 }
483 p++;
484 }
485 } else {
486 /*
487 * With NEW_ENVIRON, the sense of VAR and VALUE
488 * isn't in doubt.
489 */
490 value = RFC_VALUE;
491 var = RFC_VAR;
492 }
32874aea 493 b[0] = IAC;
494 b[1] = SB;
51470298 495 b[2] = telnet->sb_opt;
374330e2 496 b[3] = TELQUAL_IS;
497 n = 4;
86916870 498 e = telnet->cfg.environmt;
374330e2 499 while (*e) {
500 b[n++] = var;
32874aea 501 while (*e && *e != '\t')
502 b[n++] = *e++;
503 if (*e == '\t')
504 e++;
374330e2 505 b[n++] = value;
32874aea 506 while (*e)
507 b[n++] = *e++;
374330e2 508 e++;
509 }
86916870 510 if (*telnet->cfg.username) {
32874aea 511 b[n++] = var;
512 b[n++] = 'U';
513 b[n++] = 'S';
514 b[n++] = 'E';
515 b[n++] = 'R';
516 b[n++] = value;
86916870 517 e = telnet->cfg.username;
32874aea 518 while (*e)
519 b[n++] = *e++;
374330e2 520 }
32874aea 521 b[n++] = IAC;
522 b[n++] = SE;
a1fd562d 523 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
afaa639b 524 logbuf = dupprintf("client:\tSB %s IS %s%s%s%s",
525 telopt(telnet->sb_opt),
526 *telnet->cfg.username ? "USER=" : "",
527 telnet->cfg.username,
528 *telnet->cfg.username ? " " : "",
529 n == 6 ? "<nothing>" :
530 (*telnet->cfg.environmt ? "<stuff>" : ""));
a8327734 531 logevent(telnet->frontend, logbuf);
57356d63 532 sfree(logbuf);
374330e2 533 }
534 break;
535 }
536}
537
51470298 538static void do_telnet_read(Telnet telnet, char *buf, int len)
32874aea 539{
374330e2 540
541 while (len--) {
542 int c = (unsigned char) *buf++;
543
51470298 544 switch (telnet->state) {
887035a5 545 case TOP_LEVEL:
374330e2 546 case SEENCR:
51470298 547 if (c == NUL && telnet->state == SEENCR)
548 telnet->state = TOP_LEVEL;
374330e2 549 else if (c == IAC)
51470298 550 telnet->state = SEENIAC;
374330e2 551 else {
51470298 552 if (!telnet->in_synch)
553 c_write1(telnet, c);
2f938b83 554
555#if 1
556 /* I can't get the F***ing winsock to insert the urgent IAC
557 * into the right position! Even with SO_OOBINLINE it gives
558 * it to recv too soon. And of course the DM byte (that
559 * arrives in the same packet!) appears several K later!!
560 *
561 * Oh well, we do get the DM in the right place so I'll
562 * just stop hiding on the next 0xf2 and hope for the best.
563 */
32874aea 564 else if (c == DM)
51470298 565 telnet->in_synch = 0;
2f938b83 566#endif
656fa244 567 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)
51470298 568 telnet->state = SEENCR;
374330e2 569 else
51470298 570 telnet->state = TOP_LEVEL;
374330e2 571 }
572 break;
573 case SEENIAC:
32874aea 574 if (c == DO)
51470298 575 telnet->state = SEENDO;
32874aea 576 else if (c == DONT)
51470298 577 telnet->state = SEENDONT;
32874aea 578 else if (c == WILL)
51470298 579 telnet->state = SEENWILL;
32874aea 580 else if (c == WONT)
51470298 581 telnet->state = SEENWONT;
32874aea 582 else if (c == SB)
51470298 583 telnet->state = SEENSB;
2f938b83 584 else if (c == DM) {
51470298 585 telnet->in_synch = 0;
586 telnet->state = TOP_LEVEL;
32874aea 587 } else {
ded38628 588 /* ignore everything else; print it if it's IAC */
589 if (c == IAC) {
51470298 590 c_write1(telnet, c);
ded38628 591 }
51470298 592 telnet->state = TOP_LEVEL;
300d41b0 593 }
374330e2 594 break;
595 case SEENWILL:
51470298 596 proc_rec_opt(telnet, WILL, c);
597 telnet->state = TOP_LEVEL;
374330e2 598 break;
599 case SEENWONT:
51470298 600 proc_rec_opt(telnet, WONT, c);
601 telnet->state = TOP_LEVEL;
374330e2 602 break;
603 case SEENDO:
51470298 604 proc_rec_opt(telnet, DO, c);
605 telnet->state = TOP_LEVEL;
374330e2 606 break;
607 case SEENDONT:
51470298 608 proc_rec_opt(telnet, DONT, c);
609 telnet->state = TOP_LEVEL;
374330e2 610 break;
611 case SEENSB:
51470298 612 telnet->sb_opt = c;
613 telnet->sb_len = 0;
614 telnet->state = SUBNEGOT;
374330e2 615 break;
616 case SUBNEGOT:
617 if (c == IAC)
51470298 618 telnet->state = SUBNEG_IAC;
374330e2 619 else {
32874aea 620 subneg_addchar:
51470298 621 if (telnet->sb_len >= telnet->sb_size) {
51470298 622 telnet->sb_size += SB_DELTA;
3d88e64d 623 telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,
624 unsigned char);
374330e2 625 }
3d88e64d 626 telnet->sb_buf[telnet->sb_len++] = c;
51470298 627 telnet->state = SUBNEGOT; /* in case we came here by goto */
374330e2 628 }
629 break;
630 case SUBNEG_IAC:
631 if (c != SE)
632 goto subneg_addchar; /* yes, it's a hack, I know, but... */
633 else {
51470298 634 process_subneg(telnet);
635 telnet->state = TOP_LEVEL;
374330e2 636 }
637 break;
638 }
639 }
640}
641
7555d6a5 642static void telnet_log(Plug plug, int type, SockAddr addr, int port,
643 const char *error_msg, int error_code)
644{
645 Telnet telnet = (Telnet) plug;
646 char addrbuf[256], *msg;
647
648 sk_getaddr(addr, addrbuf, lenof(addrbuf));
649
650 if (type == 0)
651 msg = dupprintf("Connecting to %s port %d", addrbuf, port);
652 else
653 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
654
655 logevent(telnet->frontend, msg);
656}
657
cbe2d68f 658static int telnet_closing(Plug plug, const char *error_msg, int error_code,
32874aea 659 int calling_back)
660{
51470298 661 Telnet telnet = (Telnet) plug;
662
663 if (telnet->s) {
664 sk_close(telnet->s);
665 telnet->s = NULL;
39934deb 666 notify_remote_exit(telnet->frontend);
f3ab576e 667 }
7e78000d 668 if (error_msg) {
a8327734 669 logevent(telnet->frontend, error_msg);
971bcc0a 670 connection_fatal(telnet->frontend, "%s", error_msg);
7555d6a5 671 }
672 /* Otherwise, the remote side closed the connection normally. */
7e78000d 673 return 0;
674}
675
32874aea 676static int telnet_receive(Plug plug, int urgent, char *data, int len)
677{
51470298 678 Telnet telnet = (Telnet) plug;
32874aea 679 if (urgent)
51470298 680 telnet->in_synch = TRUE;
681 do_telnet_read(telnet, data, len);
8df7a775 682 return 1;
683}
684
3ad9d396 685static void telnet_sent(Plug plug, int bufsize)
686{
51470298 687 Telnet telnet = (Telnet) plug;
688 telnet->bufsize = bufsize;
3ad9d396 689}
690
374330e2 691/*
8df7a775 692 * Called to set up the Telnet connection.
374330e2 693 *
694 * Returns an error message, or NULL on success.
695 *
6e1ebb76 696 * Also places the canonical host name into `realhost'. It must be
697 * freed by the caller.
374330e2 698 */
cbe2d68f 699static const char *telnet_init(void *frontend_handle, void **backend_handle,
700 Config *cfg,
701 char *host, int port, char **realhost,
79bf227b 702 int nodelay, int keepalive)
32874aea 703{
51470298 704 static const struct plug_function_table fn_table = {
7555d6a5 705 telnet_log,
7e78000d 706 telnet_closing,
3ad9d396 707 telnet_receive,
708 telnet_sent
51470298 709 };
8df7a775 710 SockAddr addr;
cbe2d68f 711 const char *err;
51470298 712 Telnet telnet;
713
3d88e64d 714 telnet = snew(struct telnet_tag);
51470298 715 telnet->fn = &fn_table;
86916870 716 telnet->cfg = *cfg; /* STRUCTURE COPY */
51470298 717 telnet->s = NULL;
718 telnet->echoing = TRUE;
719 telnet->editing = TRUE;
720 telnet->activated = FALSE;
721 telnet->sb_buf = NULL;
722 telnet->sb_size = 0;
723 telnet->frontend = frontend_handle;
86916870 724 telnet->term_width = telnet->cfg.width;
725 telnet->term_height = telnet->cfg.height;
51470298 726 telnet->state = TOP_LEVEL;
cc31ab78 727 telnet->ldisc = NULL;
39934deb 728 telnet->pinger = NULL;
51470298 729 *backend_handle = telnet;
887035a5 730
374330e2 731 /*
732 * Try to find host.
733 */
3ad9d396 734 {
57356d63 735 char *buf;
05581745 736 buf = dupprintf("Looking up host \"%s\"%s", host,
737 (cfg->addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
738 (cfg->addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
739 "")));
a8327734 740 logevent(telnet->frontend, buf);
57356d63 741 sfree(buf);
3ad9d396 742 }
05581745 743 addr = name_lookup(host, port, realhost, &telnet->cfg, cfg->addressfamily);
f85e6f6e 744 if ((err = sk_addr_error(addr)) != NULL) {
745 sk_addr_free(addr);
8df7a775 746 return err;
f85e6f6e 747 }
374330e2 748
749 if (port < 0)
750 port = 23; /* default telnet port */
751
752 /*
753 * Open socket.
754 */
51470298 755 telnet->s = new_connection(addr, *realhost, port, 0, 1,
79bf227b 756 nodelay, keepalive, (Plug) telnet, &telnet->cfg);
a1fd562d 757 if ((err = sk_socket_error(telnet->s)) != NULL)
8df7a775 758 return err;
374330e2 759
39934deb 760 telnet->pinger = pinger_new(&telnet->cfg, &telnet_backend, telnet);
761
374330e2 762 /*
763 * Initialise option states.
764 */
86916870 765 if (telnet->cfg.passive_telnet) {
51470298 766 const struct Opt *const *o;
8faa456c 767
768 for (o = opts; *o; o++)
51470298 769 telnet->opt_states[(*o)->index] = INACTIVE;
8faa456c 770 } else {
51470298 771 const struct Opt *const *o;
374330e2 772
51470298 773 for (o = opts; *o; o++) {
774 telnet->opt_states[(*o)->index] = (*o)->initial_state;
775 if (telnet->opt_states[(*o)->index] == REQUESTED)
776 send_opt(telnet, (*o)->send, (*o)->option);
777 }
778 telnet->activated = TRUE;
374330e2 779 }
780
374330e2 781 /*
782 * Set up SYNCH state.
783 */
51470298 784 telnet->in_synch = FALSE;
6f34e365 785
533b1743 786 /*
787 * We can send special commands from the start.
788 */
789 update_specials_menu(telnet->frontend);
790
374330e2 791 return NULL;
792}
793
fabd1805 794static void telnet_free(void *handle)
795{
796 Telnet telnet = (Telnet) handle;
797
798 sfree(telnet->sb_buf);
799 if (telnet->s)
800 sk_close(telnet->s);
39934deb 801 if (telnet->pinger)
802 pinger_free(telnet->pinger);
fabd1805 803 sfree(telnet);
804}
374330e2 805/*
86916870 806 * Reconfigure the Telnet backend. There's no immediate action
807 * necessary, in this backend: we just save the fresh config for
808 * any subsequent negotiations.
809 */
810static void telnet_reconfig(void *handle, Config *cfg)
811{
812 Telnet telnet = (Telnet) handle;
39934deb 813 pinger_reconfig(telnet->pinger, &telnet->cfg, cfg);
86916870 814 telnet->cfg = *cfg; /* STRUCTURE COPY */
815}
816
817/*
374330e2 818 * Called to send data down the Telnet connection.
819 */
51470298 820static int telnet_send(void *handle, char *buf, int len)
32874aea 821{
51470298 822 Telnet telnet = (Telnet) handle;
a1fd562d 823 unsigned char *p, *end;
c85623f9 824 static const unsigned char iac[2] = { IAC, IAC };
825 static const unsigned char cr[2] = { CR, NUL };
a5f3e637 826#if 0
c85623f9 827 static const unsigned char nl[2] = { CR, LF };
a5f3e637 828#endif
374330e2 829
51470298 830 if (telnet->s == NULL)
5471d09a 831 return 0;
374330e2 832
a1fd562d 833 p = (unsigned char *)buf;
834 end = (unsigned char *)(buf + len);
835 while (p < end) {
836 unsigned char *q = p;
374330e2 837
a1fd562d 838 while (p < end && iswritable(*p))
32874aea 839 p++;
a1fd562d 840 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
374330e2 841
a1fd562d 842 while (p < end && !iswritable(*p)) {
51470298 843 telnet->bufsize =
a1fd562d 844 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
374330e2 845 p++;
846 }
847 }
5471d09a 848
51470298 849 return telnet->bufsize;
5471d09a 850}
851
852/*
853 * Called to query the current socket sendability status.
854 */
51470298 855static int telnet_sendbuffer(void *handle)
5471d09a 856{
51470298 857 Telnet telnet = (Telnet) handle;
858 return telnet->bufsize;
374330e2 859}
860
861/*
862 * Called to set the size of the window from Telnet's POV.
863 */
51470298 864static void telnet_size(void *handle, int width, int height)
32874aea 865{
51470298 866 Telnet telnet = (Telnet) handle;
ef41972c 867 unsigned char b[24];
868 int n;
57356d63 869 char *logbuf;
374330e2 870
51470298 871 telnet->term_width = width;
872 telnet->term_height = height;
f278d6f8 873
51470298 874 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
374330e2 875 return;
ef41972c 876 n = 0;
877 b[n++] = IAC;
878 b[n++] = SB;
879 b[n++] = TELOPT_NAWS;
880 b[n++] = telnet->term_width >> 8;
881 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
882 b[n++] = telnet->term_width & 0xFF;
883 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
884 b[n++] = telnet->term_height >> 8;
885 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
886 b[n++] = telnet->term_height & 0xFF;
887 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
888 b[n++] = IAC;
889 b[n++] = SE;
a1fd562d 890 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
57356d63 891 logbuf = dupprintf("client:\tSB NAWS %d,%d",
ef41972c 892 telnet->term_width, telnet->term_height);
a8327734 893 logevent(telnet->frontend, logbuf);
57356d63 894 sfree(logbuf);
374330e2 895}
896
897/*
898 * Send Telnet special codes.
899 */
51470298 900static void telnet_special(void *handle, Telnet_Special code)
32874aea 901{
51470298 902 Telnet telnet = (Telnet) handle;
374330e2 903 unsigned char b[2];
904
51470298 905 if (telnet->s == NULL)
374330e2 906 return;
907
908 b[0] = IAC;
909 switch (code) {
32874aea 910 case TS_AYT:
911 b[1] = AYT;
a1fd562d 912 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 913 break;
914 case TS_BRK:
915 b[1] = BREAK;
a1fd562d 916 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 917 break;
918 case TS_EC:
919 b[1] = EC;
a1fd562d 920 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 921 break;
922 case TS_EL:
923 b[1] = EL;
a1fd562d 924 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 925 break;
926 case TS_GA:
927 b[1] = GA;
a1fd562d 928 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 929 break;
930 case TS_NOP:
931 b[1] = NOP;
a1fd562d 932 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 933 break;
934 case TS_ABORT:
935 b[1] = ABORT;
a1fd562d 936 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 937 break;
938 case TS_AO:
939 b[1] = AO;
a1fd562d 940 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 941 break;
942 case TS_IP:
943 b[1] = IP;
a1fd562d 944 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 945 break;
946 case TS_SUSP:
947 b[1] = SUSP;
a1fd562d 948 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 949 break;
950 case TS_EOR:
951 b[1] = EOR;
a1fd562d 952 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 953 break;
954 case TS_EOF:
955 b[1] = xEOF;
a1fd562d 956 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 957 break;
a5f3e637 958 case TS_EOL:
6ee0cb6d 959 /* In BINARY mode, CR-LF becomes just CR -
960 * and without the NUL suffix too. */
656fa244 961 if (telnet->opt_states[o_we_bin.index] == ACTIVE)
6ee0cb6d 962 telnet->bufsize = sk_write(telnet->s, "\r", 1);
656fa244 963 else
964 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
a5f3e637 965 break;
374330e2 966 case TS_SYNCH:
32874aea 967 b[1] = DM;
a1fd562d 968 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
969 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
32874aea 970 break;
684d367c 971 case TS_RECHO:
51470298 972 if (telnet->opt_states[o_echo.index] == INACTIVE ||
973 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
974 telnet->opt_states[o_echo.index] = REQUESTED;
975 send_opt(telnet, o_echo.send, o_echo.option);
684d367c 976 }
977 break;
978 case TS_LECHO:
51470298 979 if (telnet->opt_states[o_echo.index] == ACTIVE) {
980 telnet->opt_states[o_echo.index] = REQUESTED;
981 send_opt(telnet, o_echo.nsend, o_echo.option);
684d367c 982 }
374330e2 983 break;
32874aea 984 case TS_PING:
51470298 985 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
32874aea 986 b[1] = NOP;
a1fd562d 987 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
ec55b220 988 }
32874aea 989 break;
6f2d0cde 990 default:
991 break; /* never heard of it */
374330e2 992 }
993}
994
125105d1 995static const struct telnet_special *telnet_get_specials(void *handle)
996{
997 static const struct telnet_special specials[] = {
998 {"Are You There", TS_AYT},
999 {"Break", TS_BRK},
1000 {"Synch", TS_SYNCH},
1001 {"Erase Character", TS_EC},
1002 {"Erase Line", TS_EL},
1003 {"Go Ahead", TS_GA},
1004 {"No Operation", TS_NOP},
6f2d0cde 1005 {NULL, TS_SEP},
125105d1 1006 {"Abort Process", TS_ABORT},
1007 {"Abort Output", TS_AO},
1008 {"Interrupt Process", TS_IP},
1009 {"Suspend Process", TS_SUSP},
6f2d0cde 1010 {NULL, TS_SEP},
125105d1 1011 {"End Of Record", TS_EOR},
1012 {"End Of File", TS_EOF},
6f2d0cde 1013 {NULL, TS_EXITMENU}
125105d1 1014 };
1015 return specials;
1016}
1017
51470298 1018static Socket telnet_socket(void *handle)
32874aea 1019{
51470298 1020 Telnet telnet = (Telnet) handle;
1021 return telnet->s;
32874aea 1022}
8ccc75b0 1023
51470298 1024static int telnet_sendok(void *handle)
32874aea 1025{
68a49acb 1026 /* Telnet telnet = (Telnet) handle; */
32874aea 1027 return 1;
1028}
4017be6d 1029
51470298 1030static void telnet_unthrottle(void *handle, int backlog)
5471d09a 1031{
51470298 1032 Telnet telnet = (Telnet) handle;
1033 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
5471d09a 1034}
1035
51470298 1036static int telnet_ldisc(void *handle, int option)
32874aea 1037{
51470298 1038 Telnet telnet = (Telnet) handle;
32874aea 1039 if (option == LD_ECHO)
51470298 1040 return telnet->echoing;
32874aea 1041 if (option == LD_EDIT)
51470298 1042 return telnet->editing;
0965bee0 1043 return FALSE;
1044}
1045
b9d7bcad 1046static void telnet_provide_ldisc(void *handle, void *ldisc)
1047{
1048 Telnet telnet = (Telnet) handle;
1049 telnet->ldisc = ldisc;
1050}
1051
a8327734 1052static void telnet_provide_logctx(void *handle, void *logctx)
1053{
1054 /* This is a stub. */
1055}
1056
51470298 1057static int telnet_exitcode(void *handle)
d8d6c7e5 1058{
0da1a790 1059 Telnet telnet = (Telnet) handle;
1060 if (telnet->s != NULL)
1061 return -1; /* still connected */
1062 else
1063 /* Telnet doesn't transmit exit codes back to the client */
1064 return 0;
d8d6c7e5 1065}
1066
f89c3294 1067/*
1068 * cfg_info for Telnet does nothing at all.
1069 */
1070static int telnet_cfg_info(void *handle)
1071{
1072 return 0;
1073}
1074
374330e2 1075Backend telnet_backend = {
1076 telnet_init,
fabd1805 1077 telnet_free,
86916870 1078 telnet_reconfig,
374330e2 1079 telnet_send,
5471d09a 1080 telnet_sendbuffer,
374330e2 1081 telnet_size,
4017be6d 1082 telnet_special,
125105d1 1083 telnet_get_specials,
8ccc75b0 1084 telnet_socket,
d8d6c7e5 1085 telnet_exitcode,
97db3be4 1086 telnet_sendok,
0965bee0 1087 telnet_ldisc,
b9d7bcad 1088 telnet_provide_ldisc,
a8327734 1089 telnet_provide_logctx,
5471d09a 1090 telnet_unthrottle,
f89c3294 1091 telnet_cfg_info,
97db3be4 1092 23
374330e2 1093};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator