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