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Reorganisation of misc.c: Minefield has moved out to winmisc.c, and
[u/mdw/putty] / telnet.c
CommitLineData
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 };
199static const struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
200 OPTINDEX_OENV, INACTIVE
32874aea 201};
51470298 202static const struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
203 OPTINDEX_NENV, REQUESTED
32874aea 204};
51470298 205static const struct Opt o_echo =
206 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
207static const struct Opt o_we_sga =
208 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
209static const struct Opt o_they_sga =
210 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
656fa244 211static const struct Opt o_we_bin =
212 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };
213static const struct Opt o_they_bin =
214 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };
51470298 215
216static const struct Opt *const opts[] = {
374330e2 217 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
656fa244 218 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL
374330e2 219};
220
51470298 221typedef struct telnet_tag {
222 const struct plug_function_table *fn;
223 /* the above field _must_ be first in the structure */
224
225 Socket s;
226
227 void *frontend;
b9d7bcad 228 void *ldisc;
51470298 229 int term_width, term_height;
230
231 int opt_states[NUM_OPTS];
232
233 int echoing, editing;
234 int activated;
235 int bufsize;
236 int in_synch;
237 int sb_opt, sb_len;
a1fd562d 238 unsigned char *sb_buf;
51470298 239 int sb_size;
240
241 enum {
242 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
243 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
244 } state;
245
86916870 246 Config cfg;
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
397 * cope with. So send a negative ack.
398 */
51470298 399 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
374330e2 400}
401
51470298 402static void process_subneg(Telnet telnet)
32874aea 403{
374330e2 404 unsigned char b[2048], *p, *q;
405 int var, value, n;
406 char *e;
407
51470298 408 switch (telnet->sb_opt) {
374330e2 409 case TELOPT_TSPEED:
51470298 410 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
57356d63 411 char *logbuf;
32874aea 412 b[0] = IAC;
413 b[1] = SB;
414 b[2] = TELOPT_TSPEED;
374330e2 415 b[3] = TELQUAL_IS;
86916870 416 strcpy((char *)(b + 4), telnet->cfg.termspeed);
417 n = 4 + strlen(telnet->cfg.termspeed);
32874aea 418 b[n] = IAC;
419 b[n + 1] = SE;
a1fd562d 420 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
a8327734 421 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
86916870 422 logbuf = dupprintf("client:\tSB TSPEED IS %s", telnet->cfg.termspeed);
a8327734 423 logevent(telnet->frontend, logbuf);
57356d63 424 sfree(logbuf);
374330e2 425 } else
a8327734 426 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
374330e2 427 break;
428 case TELOPT_TTYPE:
51470298 429 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
57356d63 430 char *logbuf;
32874aea 431 b[0] = IAC;
432 b[1] = SB;
433 b[2] = TELOPT_TTYPE;
374330e2 434 b[3] = TELQUAL_IS;
86916870 435 for (n = 0; telnet->cfg.termtype[n]; n++)
436 b[n + 4] = (telnet->cfg.termtype[n] >= 'a'
437 && telnet->cfg.termtype[n] <=
438 'z' ? telnet->cfg.termtype[n] + 'A' -
439 'a' : telnet->cfg.termtype[n]);
32874aea 440 b[n + 4] = IAC;
441 b[n + 5] = SE;
a1fd562d 442 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);
32874aea 443 b[n + 4] = 0;
a8327734 444 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
57356d63 445 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
a8327734 446 logevent(telnet->frontend, logbuf);
57356d63 447 sfree(logbuf);
374330e2 448 } else
a8327734 449 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
374330e2 450 break;
451 case TELOPT_OLD_ENVIRON:
32874aea 452 case TELOPT_NEW_ENVIRON:
51470298 453 p = telnet->sb_buf;
454 q = p + telnet->sb_len;
374330e2 455 if (p < q && *p == TELQUAL_SEND) {
57356d63 456 char *logbuf;
374330e2 457 p++;
57356d63 458 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
a8327734 459 logevent(telnet->frontend, logbuf);
57356d63 460 sfree(logbuf);
51470298 461 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
86916870 462 if (telnet->cfg.rfc_environ) {
374330e2 463 value = RFC_VALUE;
464 var = RFC_VAR;
465 } else {
466 value = BSD_VALUE;
467 var = BSD_VAR;
468 }
469 /*
470 * Try to guess the sense of VAR and VALUE.
471 */
472 while (p < q) {
473 if (*p == RFC_VAR) {
474 value = RFC_VALUE;
475 var = RFC_VAR;
476 } else if (*p == BSD_VAR) {
477 value = BSD_VALUE;
478 var = BSD_VAR;
479 }
480 p++;
481 }
482 } else {
483 /*
484 * With NEW_ENVIRON, the sense of VAR and VALUE
485 * isn't in doubt.
486 */
487 value = RFC_VALUE;
488 var = RFC_VAR;
489 }
32874aea 490 b[0] = IAC;
491 b[1] = SB;
51470298 492 b[2] = telnet->sb_opt;
374330e2 493 b[3] = TELQUAL_IS;
494 n = 4;
86916870 495 e = telnet->cfg.environmt;
374330e2 496 while (*e) {
497 b[n++] = var;
32874aea 498 while (*e && *e != '\t')
499 b[n++] = *e++;
500 if (*e == '\t')
501 e++;
374330e2 502 b[n++] = value;
32874aea 503 while (*e)
504 b[n++] = *e++;
374330e2 505 e++;
506 }
86916870 507 if (*telnet->cfg.username) {
32874aea 508 b[n++] = var;
509 b[n++] = 'U';
510 b[n++] = 'S';
511 b[n++] = 'E';
512 b[n++] = 'R';
513 b[n++] = value;
86916870 514 e = telnet->cfg.username;
32874aea 515 while (*e)
516 b[n++] = *e++;
374330e2 517 }
32874aea 518 b[n++] = IAC;
519 b[n++] = SE;
a1fd562d 520 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
57356d63 521 logbuf = dupprintf("client:\tSB %s IS %s", telopt(telnet->sb_opt),
522 n == 6 ? "<nothing>" : "<stuff>");
a8327734 523 logevent(telnet->frontend, logbuf);
57356d63 524 sfree(logbuf);
374330e2 525 }
526 break;
527 }
528}
529
51470298 530static void do_telnet_read(Telnet telnet, char *buf, int len)
32874aea 531{
374330e2 532
533 while (len--) {
534 int c = (unsigned char) *buf++;
535
51470298 536 switch (telnet->state) {
887035a5 537 case TOP_LEVEL:
374330e2 538 case SEENCR:
51470298 539 if (c == NUL && telnet->state == SEENCR)
540 telnet->state = TOP_LEVEL;
374330e2 541 else if (c == IAC)
51470298 542 telnet->state = SEENIAC;
374330e2 543 else {
51470298 544 if (!telnet->in_synch)
545 c_write1(telnet, c);
2f938b83 546
547#if 1
548 /* I can't get the F***ing winsock to insert the urgent IAC
549 * into the right position! Even with SO_OOBINLINE it gives
550 * it to recv too soon. And of course the DM byte (that
551 * arrives in the same packet!) appears several K later!!
552 *
553 * Oh well, we do get the DM in the right place so I'll
554 * just stop hiding on the next 0xf2 and hope for the best.
555 */
32874aea 556 else if (c == DM)
51470298 557 telnet->in_synch = 0;
2f938b83 558#endif
656fa244 559 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)
51470298 560 telnet->state = SEENCR;
374330e2 561 else
51470298 562 telnet->state = TOP_LEVEL;
374330e2 563 }
564 break;
565 case SEENIAC:
32874aea 566 if (c == DO)
51470298 567 telnet->state = SEENDO;
32874aea 568 else if (c == DONT)
51470298 569 telnet->state = SEENDONT;
32874aea 570 else if (c == WILL)
51470298 571 telnet->state = SEENWILL;
32874aea 572 else if (c == WONT)
51470298 573 telnet->state = SEENWONT;
32874aea 574 else if (c == SB)
51470298 575 telnet->state = SEENSB;
2f938b83 576 else if (c == DM) {
51470298 577 telnet->in_synch = 0;
578 telnet->state = TOP_LEVEL;
32874aea 579 } else {
ded38628 580 /* ignore everything else; print it if it's IAC */
581 if (c == IAC) {
51470298 582 c_write1(telnet, c);
ded38628 583 }
51470298 584 telnet->state = TOP_LEVEL;
300d41b0 585 }
374330e2 586 break;
587 case SEENWILL:
51470298 588 proc_rec_opt(telnet, WILL, c);
589 telnet->state = TOP_LEVEL;
374330e2 590 break;
591 case SEENWONT:
51470298 592 proc_rec_opt(telnet, WONT, c);
593 telnet->state = TOP_LEVEL;
374330e2 594 break;
595 case SEENDO:
51470298 596 proc_rec_opt(telnet, DO, c);
597 telnet->state = TOP_LEVEL;
374330e2 598 break;
599 case SEENDONT:
51470298 600 proc_rec_opt(telnet, DONT, c);
601 telnet->state = TOP_LEVEL;
374330e2 602 break;
603 case SEENSB:
51470298 604 telnet->sb_opt = c;
605 telnet->sb_len = 0;
606 telnet->state = SUBNEGOT;
374330e2 607 break;
608 case SUBNEGOT:
609 if (c == IAC)
51470298 610 telnet->state = SUBNEG_IAC;
374330e2 611 else {
32874aea 612 subneg_addchar:
51470298 613 if (telnet->sb_len >= telnet->sb_size) {
a1fd562d 614 unsigned char *newbuf;
51470298 615 telnet->sb_size += SB_DELTA;
616 newbuf = (telnet->sb_buf ?
617 srealloc(telnet->sb_buf, telnet->sb_size) :
618 smalloc(telnet->sb_size));
374330e2 619 if (newbuf)
51470298 620 telnet->sb_buf = newbuf;
374330e2 621 else
51470298 622 telnet->sb_size -= SB_DELTA;
374330e2 623 }
51470298 624 if (telnet->sb_len < telnet->sb_size)
625 telnet->sb_buf[telnet->sb_len++] = c;
626 telnet->state = SUBNEGOT; /* in case we came here by goto */
374330e2 627 }
628 break;
629 case SUBNEG_IAC:
630 if (c != SE)
631 goto subneg_addchar; /* yes, it's a hack, I know, but... */
632 else {
51470298 633 process_subneg(telnet);
634 telnet->state = TOP_LEVEL;
374330e2 635 }
636 break;
637 }
638 }
639}
640
32874aea 641static int telnet_closing(Plug plug, char *error_msg, int error_code,
642 int calling_back)
643{
51470298 644 Telnet telnet = (Telnet) plug;
645
646 if (telnet->s) {
647 sk_close(telnet->s);
648 telnet->s = NULL;
f3ab576e 649 }
7e78000d 650 if (error_msg) {
32874aea 651 /* A socket error has occurred. */
a8327734 652 logevent(telnet->frontend, error_msg);
247308b5 653 connection_fatal("%s", error_msg);
32874aea 654 } /* Otherwise, the remote side closed the connection normally. */
7e78000d 655 return 0;
656}
657
32874aea 658static int telnet_receive(Plug plug, int urgent, char *data, int len)
659{
51470298 660 Telnet telnet = (Telnet) plug;
32874aea 661 if (urgent)
51470298 662 telnet->in_synch = TRUE;
663 do_telnet_read(telnet, data, len);
8df7a775 664 return 1;
665}
666
3ad9d396 667static void telnet_sent(Plug plug, int bufsize)
668{
51470298 669 Telnet telnet = (Telnet) plug;
670 telnet->bufsize = bufsize;
3ad9d396 671}
672
374330e2 673/*
8df7a775 674 * Called to set up the Telnet connection.
374330e2 675 *
676 * Returns an error message, or NULL on success.
677 *
6e1ebb76 678 * Also places the canonical host name into `realhost'. It must be
679 * freed by the caller.
374330e2 680 */
51470298 681static char *telnet_init(void *frontend_handle, void **backend_handle,
86916870 682 Config *cfg,
887035a5 683 char *host, int port, char **realhost, int nodelay)
32874aea 684{
51470298 685 static const struct plug_function_table fn_table = {
7e78000d 686 telnet_closing,
3ad9d396 687 telnet_receive,
688 telnet_sent
51470298 689 };
8df7a775 690 SockAddr addr;
691 char *err;
51470298 692 Telnet telnet;
693
694 telnet = smalloc(sizeof(*telnet));
695 telnet->fn = &fn_table;
86916870 696 telnet->cfg = *cfg; /* STRUCTURE COPY */
51470298 697 telnet->s = NULL;
698 telnet->echoing = TRUE;
699 telnet->editing = TRUE;
700 telnet->activated = FALSE;
701 telnet->sb_buf = NULL;
702 telnet->sb_size = 0;
703 telnet->frontend = frontend_handle;
86916870 704 telnet->term_width = telnet->cfg.width;
705 telnet->term_height = telnet->cfg.height;
51470298 706 telnet->state = TOP_LEVEL;
707 *backend_handle = telnet;
887035a5 708
374330e2 709 /*
710 * Try to find host.
711 */
3ad9d396 712 {
57356d63 713 char *buf;
714 buf = dupprintf("Looking up host \"%s\"", host);
a8327734 715 logevent(telnet->frontend, buf);
57356d63 716 sfree(buf);
3ad9d396 717 }
e8fa8f62 718 addr = name_lookup(host, port, realhost, &telnet->cfg);
a1fd562d 719 if ((err = sk_addr_error(addr)) != NULL)
8df7a775 720 return err;
374330e2 721
722 if (port < 0)
723 port = 23; /* default telnet port */
724
725 /*
726 * Open socket.
727 */
3ad9d396 728 {
57356d63 729 char *buf, addrbuf[100];
3ad9d396 730 sk_getaddr(addr, addrbuf, 100);
57356d63 731 buf = dupprintf("Connecting to %s port %d", addrbuf, port);
a8327734 732 logevent(telnet->frontend, buf);
57356d63 733 sfree(buf);
3ad9d396 734 }
51470298 735 telnet->s = new_connection(addr, *realhost, port, 0, 1,
e8fa8f62 736 nodelay, (Plug) telnet, &telnet->cfg);
a1fd562d 737 if ((err = sk_socket_error(telnet->s)) != NULL)
8df7a775 738 return err;
374330e2 739
8df7a775 740 sk_addr_free(addr);
374330e2 741
742 /*
743 * Initialise option states.
744 */
86916870 745 if (telnet->cfg.passive_telnet) {
51470298 746 const struct Opt *const *o;
8faa456c 747
748 for (o = opts; *o; o++)
51470298 749 telnet->opt_states[(*o)->index] = INACTIVE;
8faa456c 750 } else {
51470298 751 const struct Opt *const *o;
374330e2 752
51470298 753 for (o = opts; *o; o++) {
754 telnet->opt_states[(*o)->index] = (*o)->initial_state;
755 if (telnet->opt_states[(*o)->index] == REQUESTED)
756 send_opt(telnet, (*o)->send, (*o)->option);
757 }
758 telnet->activated = TRUE;
374330e2 759 }
760
374330e2 761 /*
762 * Set up SYNCH state.
763 */
51470298 764 telnet->in_synch = FALSE;
6f34e365 765
374330e2 766 return NULL;
767}
768
fabd1805 769static void telnet_free(void *handle)
770{
771 Telnet telnet = (Telnet) handle;
772
773 sfree(telnet->sb_buf);
774 if (telnet->s)
775 sk_close(telnet->s);
776 sfree(telnet);
777}
374330e2 778/*
86916870 779 * Reconfigure the Telnet backend. There's no immediate action
780 * necessary, in this backend: we just save the fresh config for
781 * any subsequent negotiations.
782 */
783static void telnet_reconfig(void *handle, Config *cfg)
784{
785 Telnet telnet = (Telnet) handle;
786 telnet->cfg = *cfg; /* STRUCTURE COPY */
787}
788
789/*
374330e2 790 * Called to send data down the Telnet connection.
791 */
51470298 792static int telnet_send(void *handle, char *buf, int len)
32874aea 793{
51470298 794 Telnet telnet = (Telnet) handle;
a1fd562d 795 unsigned char *p, *end;
c85623f9 796 static const unsigned char iac[2] = { IAC, IAC };
797 static const unsigned char cr[2] = { CR, NUL };
a5f3e637 798#if 0
c85623f9 799 static const unsigned char nl[2] = { CR, LF };
a5f3e637 800#endif
374330e2 801
51470298 802 if (telnet->s == NULL)
5471d09a 803 return 0;
374330e2 804
a1fd562d 805 p = (unsigned char *)buf;
806 end = (unsigned char *)(buf + len);
807 while (p < end) {
808 unsigned char *q = p;
374330e2 809
a1fd562d 810 while (p < end && iswritable(*p))
32874aea 811 p++;
a1fd562d 812 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
374330e2 813
a1fd562d 814 while (p < end && !iswritable(*p)) {
51470298 815 telnet->bufsize =
a1fd562d 816 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
374330e2 817 p++;
818 }
819 }
5471d09a 820
51470298 821 return telnet->bufsize;
5471d09a 822}
823
824/*
825 * Called to query the current socket sendability status.
826 */
51470298 827static int telnet_sendbuffer(void *handle)
5471d09a 828{
51470298 829 Telnet telnet = (Telnet) handle;
830 return telnet->bufsize;
374330e2 831}
832
833/*
834 * Called to set the size of the window from Telnet's POV.
835 */
51470298 836static void telnet_size(void *handle, int width, int height)
32874aea 837{
51470298 838 Telnet telnet = (Telnet) handle;
ef41972c 839 unsigned char b[24];
840 int n;
57356d63 841 char *logbuf;
374330e2 842
51470298 843 telnet->term_width = width;
844 telnet->term_height = height;
f278d6f8 845
51470298 846 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
374330e2 847 return;
ef41972c 848 n = 0;
849 b[n++] = IAC;
850 b[n++] = SB;
851 b[n++] = TELOPT_NAWS;
852 b[n++] = telnet->term_width >> 8;
853 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
854 b[n++] = telnet->term_width & 0xFF;
855 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
856 b[n++] = telnet->term_height >> 8;
857 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
858 b[n++] = telnet->term_height & 0xFF;
859 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
860 b[n++] = IAC;
861 b[n++] = SE;
a1fd562d 862 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
57356d63 863 logbuf = dupprintf("client:\tSB NAWS %d,%d",
ef41972c 864 telnet->term_width, telnet->term_height);
a8327734 865 logevent(telnet->frontend, logbuf);
57356d63 866 sfree(logbuf);
374330e2 867}
868
869/*
870 * Send Telnet special codes.
871 */
51470298 872static void telnet_special(void *handle, Telnet_Special code)
32874aea 873{
51470298 874 Telnet telnet = (Telnet) handle;
374330e2 875 unsigned char b[2];
876
51470298 877 if (telnet->s == NULL)
374330e2 878 return;
879
880 b[0] = IAC;
881 switch (code) {
32874aea 882 case TS_AYT:
883 b[1] = AYT;
a1fd562d 884 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 885 break;
886 case TS_BRK:
887 b[1] = BREAK;
a1fd562d 888 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 889 break;
890 case TS_EC:
891 b[1] = EC;
a1fd562d 892 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 893 break;
894 case TS_EL:
895 b[1] = EL;
a1fd562d 896 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 897 break;
898 case TS_GA:
899 b[1] = GA;
a1fd562d 900 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 901 break;
902 case TS_NOP:
903 b[1] = NOP;
a1fd562d 904 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 905 break;
906 case TS_ABORT:
907 b[1] = ABORT;
a1fd562d 908 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 909 break;
910 case TS_AO:
911 b[1] = AO;
a1fd562d 912 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 913 break;
914 case TS_IP:
915 b[1] = IP;
a1fd562d 916 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 917 break;
918 case TS_SUSP:
919 b[1] = SUSP;
a1fd562d 920 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 921 break;
922 case TS_EOR:
923 b[1] = EOR;
a1fd562d 924 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 925 break;
926 case TS_EOF:
927 b[1] = xEOF;
a1fd562d 928 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 929 break;
a5f3e637 930 case TS_EOL:
656fa244 931 /* In BINARY mode, CR-LF becomes just CR. */
932 if (telnet->opt_states[o_we_bin.index] == ACTIVE)
933 telnet->bufsize = sk_write(telnet->s, "\r", 2);
934 else
935 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
a5f3e637 936 break;
374330e2 937 case TS_SYNCH:
32874aea 938 b[1] = DM;
a1fd562d 939 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
940 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
32874aea 941 break;
684d367c 942 case TS_RECHO:
51470298 943 if (telnet->opt_states[o_echo.index] == INACTIVE ||
944 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
945 telnet->opt_states[o_echo.index] = REQUESTED;
946 send_opt(telnet, o_echo.send, o_echo.option);
684d367c 947 }
948 break;
949 case TS_LECHO:
51470298 950 if (telnet->opt_states[o_echo.index] == ACTIVE) {
951 telnet->opt_states[o_echo.index] = REQUESTED;
952 send_opt(telnet, o_echo.nsend, o_echo.option);
684d367c 953 }
374330e2 954 break;
32874aea 955 case TS_PING:
51470298 956 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
32874aea 957 b[1] = NOP;
a1fd562d 958 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
ec55b220 959 }
32874aea 960 break;
374330e2 961 }
962}
963
51470298 964static Socket telnet_socket(void *handle)
32874aea 965{
51470298 966 Telnet telnet = (Telnet) handle;
967 return telnet->s;
32874aea 968}
8ccc75b0 969
51470298 970static int telnet_sendok(void *handle)
32874aea 971{
68a49acb 972 /* Telnet telnet = (Telnet) handle; */
32874aea 973 return 1;
974}
4017be6d 975
51470298 976static void telnet_unthrottle(void *handle, int backlog)
5471d09a 977{
51470298 978 Telnet telnet = (Telnet) handle;
979 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
5471d09a 980}
981
51470298 982static int telnet_ldisc(void *handle, int option)
32874aea 983{
51470298 984 Telnet telnet = (Telnet) handle;
32874aea 985 if (option == LD_ECHO)
51470298 986 return telnet->echoing;
32874aea 987 if (option == LD_EDIT)
51470298 988 return telnet->editing;
0965bee0 989 return FALSE;
990}
991
b9d7bcad 992static void telnet_provide_ldisc(void *handle, void *ldisc)
993{
994 Telnet telnet = (Telnet) handle;
995 telnet->ldisc = ldisc;
996}
997
a8327734 998static void telnet_provide_logctx(void *handle, void *logctx)
999{
1000 /* This is a stub. */
1001}
1002
51470298 1003static int telnet_exitcode(void *handle)
d8d6c7e5 1004{
68a49acb 1005 /* Telnet telnet = (Telnet) handle; */
d8d6c7e5 1006 /* Telnet doesn't transmit exit codes back to the client */
1007 return 0;
1008}
1009
374330e2 1010Backend telnet_backend = {
1011 telnet_init,
fabd1805 1012 telnet_free,
86916870 1013 telnet_reconfig,
374330e2 1014 telnet_send,
5471d09a 1015 telnet_sendbuffer,
374330e2 1016 telnet_size,
4017be6d 1017 telnet_special,
8ccc75b0 1018 telnet_socket,
d8d6c7e5 1019 telnet_exitcode,
97db3be4 1020 telnet_sendok,
0965bee0 1021 telnet_ldisc,
b9d7bcad 1022 telnet_provide_ldisc,
a8327734 1023 telnet_provide_logctx,
5471d09a 1024 telnet_unthrottle,
97db3be4 1025 23
374330e2 1026};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator