projects / u / mdw / putty / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
The latest unfix.org IPv6 patch contains these apparently
[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;
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
cbe2d68f 641static int telnet_closing(Plug plug, const char *error_msg, int error_code,
32874aea 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;
39934deb 649 notify_remote_exit(telnet->frontend);
f3ab576e 650 }
7e78000d 651 if (error_msg) {
32874aea 652 /* A socket error has occurred. */
a8327734 653 logevent(telnet->frontend, error_msg);
971bcc0a 654 connection_fatal(telnet->frontend, "%s", error_msg);
32874aea 655 } /* Otherwise, the remote side closed the connection normally. */
7e78000d 656 return 0;
657}
658
32874aea 659static int telnet_receive(Plug plug, int urgent, char *data, int len)
660{
51470298 661 Telnet telnet = (Telnet) plug;
32874aea 662 if (urgent)
51470298 663 telnet->in_synch = TRUE;
664 do_telnet_read(telnet, data, len);
8df7a775 665 return 1;
666}
667
3ad9d396 668static void telnet_sent(Plug plug, int bufsize)
669{
51470298 670 Telnet telnet = (Telnet) plug;
671 telnet->bufsize = bufsize;
3ad9d396 672}
673
374330e2 674/*
8df7a775 675 * Called to set up the Telnet connection.
374330e2 676 *
677 * Returns an error message, or NULL on success.
678 *
6e1ebb76 679 * Also places the canonical host name into `realhost'. It must be
680 * freed by the caller.
374330e2 681 */
cbe2d68f 682static const char *telnet_init(void *frontend_handle, void **backend_handle,
683 Config *cfg,
684 char *host, int port, char **realhost,
79bf227b 685 int nodelay, int keepalive)
32874aea 686{
51470298 687 static const struct plug_function_table fn_table = {
7e78000d 688 telnet_closing,
3ad9d396 689 telnet_receive,
690 telnet_sent
51470298 691 };
8df7a775 692 SockAddr addr;
cbe2d68f 693 const char *err;
51470298 694 Telnet telnet;
695
3d88e64d 696 telnet = snew(struct telnet_tag);
51470298 697 telnet->fn = &fn_table;
86916870 698 telnet->cfg = *cfg; /* STRUCTURE COPY */
51470298 699 telnet->s = NULL;
700 telnet->echoing = TRUE;
701 telnet->editing = TRUE;
702 telnet->activated = FALSE;
703 telnet->sb_buf = NULL;
704 telnet->sb_size = 0;
705 telnet->frontend = frontend_handle;
86916870 706 telnet->term_width = telnet->cfg.width;
707 telnet->term_height = telnet->cfg.height;
51470298 708 telnet->state = TOP_LEVEL;
cc31ab78 709 telnet->ldisc = NULL;
39934deb 710 telnet->pinger = NULL;
51470298 711 *backend_handle = telnet;
887035a5 712
374330e2 713 /*
714 * Try to find host.
715 */
3ad9d396 716 {
57356d63 717 char *buf;
718 buf = dupprintf("Looking up host \"%s\"", host);
a8327734 719 logevent(telnet->frontend, buf);
57356d63 720 sfree(buf);
3ad9d396 721 }
e8fa8f62 722 addr = name_lookup(host, port, realhost, &telnet->cfg);
f85e6f6e 723 if ((err = sk_addr_error(addr)) != NULL) {
724 sk_addr_free(addr);
8df7a775 725 return err;
f85e6f6e 726 }
374330e2 727
728 if (port < 0)
729 port = 23; /* default telnet port */
730
731 /*
732 * Open socket.
733 */
3ad9d396 734 {
57356d63 735 char *buf, addrbuf[100];
3ad9d396 736 sk_getaddr(addr, addrbuf, 100);
57356d63 737 buf = dupprintf("Connecting to %s port %d", addrbuf, port);
a8327734 738 logevent(telnet->frontend, buf);
57356d63 739 sfree(buf);
3ad9d396 740 }
51470298 741 telnet->s = new_connection(addr, *realhost, port, 0, 1,
79bf227b 742 nodelay, keepalive, (Plug) telnet, &telnet->cfg);
a1fd562d 743 if ((err = sk_socket_error(telnet->s)) != NULL)
8df7a775 744 return err;
374330e2 745
39934deb 746 telnet->pinger = pinger_new(&telnet->cfg, &telnet_backend, telnet);
747
374330e2 748 /*
749 * Initialise option states.
750 */
86916870 751 if (telnet->cfg.passive_telnet) {
51470298 752 const struct Opt *const *o;
8faa456c 753
754 for (o = opts; *o; o++)
51470298 755 telnet->opt_states[(*o)->index] = INACTIVE;
8faa456c 756 } else {
51470298 757 const struct Opt *const *o;
374330e2 758
51470298 759 for (o = opts; *o; o++) {
760 telnet->opt_states[(*o)->index] = (*o)->initial_state;
761 if (telnet->opt_states[(*o)->index] == REQUESTED)
762 send_opt(telnet, (*o)->send, (*o)->option);
763 }
764 telnet->activated = TRUE;
374330e2 765 }
766
374330e2 767 /*
768 * Set up SYNCH state.
769 */
51470298 770 telnet->in_synch = FALSE;
6f34e365 771
533b1743 772 /*
773 * We can send special commands from the start.
774 */
775 update_specials_menu(telnet->frontend);
776
374330e2 777 return NULL;
778}
779
fabd1805 780static void telnet_free(void *handle)
781{
782 Telnet telnet = (Telnet) handle;
783
784 sfree(telnet->sb_buf);
785 if (telnet->s)
786 sk_close(telnet->s);
39934deb 787 if (telnet->pinger)
788 pinger_free(telnet->pinger);
fabd1805 789 sfree(telnet);
790}
374330e2 791/*
86916870 792 * Reconfigure the Telnet backend. There's no immediate action
793 * necessary, in this backend: we just save the fresh config for
794 * any subsequent negotiations.
795 */
796static void telnet_reconfig(void *handle, Config *cfg)
797{
798 Telnet telnet = (Telnet) handle;
39934deb 799 pinger_reconfig(telnet->pinger, &telnet->cfg, cfg);
86916870 800 telnet->cfg = *cfg; /* STRUCTURE COPY */
801}
802
803/*
374330e2 804 * Called to send data down the Telnet connection.
805 */
51470298 806static int telnet_send(void *handle, char *buf, int len)
32874aea 807{
51470298 808 Telnet telnet = (Telnet) handle;
a1fd562d 809 unsigned char *p, *end;
c85623f9 810 static const unsigned char iac[2] = { IAC, IAC };
811 static const unsigned char cr[2] = { CR, NUL };
a5f3e637 812#if 0
c85623f9 813 static const unsigned char nl[2] = { CR, LF };
a5f3e637 814#endif
374330e2 815
51470298 816 if (telnet->s == NULL)
5471d09a 817 return 0;
374330e2 818
a1fd562d 819 p = (unsigned char *)buf;
820 end = (unsigned char *)(buf + len);
821 while (p < end) {
822 unsigned char *q = p;
374330e2 823
a1fd562d 824 while (p < end && iswritable(*p))
32874aea 825 p++;
a1fd562d 826 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
374330e2 827
a1fd562d 828 while (p < end && !iswritable(*p)) {
51470298 829 telnet->bufsize =
a1fd562d 830 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
374330e2 831 p++;
832 }
833 }
5471d09a 834
51470298 835 return telnet->bufsize;
5471d09a 836}
837
838/*
839 * Called to query the current socket sendability status.
840 */
51470298 841static int telnet_sendbuffer(void *handle)
5471d09a 842{
51470298 843 Telnet telnet = (Telnet) handle;
844 return telnet->bufsize;
374330e2 845}
846
847/*
848 * Called to set the size of the window from Telnet's POV.
849 */
51470298 850static void telnet_size(void *handle, int width, int height)
32874aea 851{
51470298 852 Telnet telnet = (Telnet) handle;
ef41972c 853 unsigned char b[24];
854 int n;
57356d63 855 char *logbuf;
374330e2 856
51470298 857 telnet->term_width = width;
858 telnet->term_height = height;
f278d6f8 859
51470298 860 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
374330e2 861 return;
ef41972c 862 n = 0;
863 b[n++] = IAC;
864 b[n++] = SB;
865 b[n++] = TELOPT_NAWS;
866 b[n++] = telnet->term_width >> 8;
867 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
868 b[n++] = telnet->term_width & 0xFF;
869 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
870 b[n++] = telnet->term_height >> 8;
871 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
872 b[n++] = telnet->term_height & 0xFF;
873 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
874 b[n++] = IAC;
875 b[n++] = SE;
a1fd562d 876 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
57356d63 877 logbuf = dupprintf("client:\tSB NAWS %d,%d",
ef41972c 878 telnet->term_width, telnet->term_height);
a8327734 879 logevent(telnet->frontend, logbuf);
57356d63 880 sfree(logbuf);
374330e2 881}
882
883/*
884 * Send Telnet special codes.
885 */
51470298 886static void telnet_special(void *handle, Telnet_Special code)
32874aea 887{
51470298 888 Telnet telnet = (Telnet) handle;
374330e2 889 unsigned char b[2];
890
51470298 891 if (telnet->s == NULL)
374330e2 892 return;
893
894 b[0] = IAC;
895 switch (code) {
32874aea 896 case TS_AYT:
897 b[1] = AYT;
a1fd562d 898 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 899 break;
900 case TS_BRK:
901 b[1] = BREAK;
a1fd562d 902 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 903 break;
904 case TS_EC:
905 b[1] = EC;
a1fd562d 906 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 907 break;
908 case TS_EL:
909 b[1] = EL;
a1fd562d 910 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 911 break;
912 case TS_GA:
913 b[1] = GA;
a1fd562d 914 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 915 break;
916 case TS_NOP:
917 b[1] = NOP;
a1fd562d 918 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 919 break;
920 case TS_ABORT:
921 b[1] = ABORT;
a1fd562d 922 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 923 break;
924 case TS_AO:
925 b[1] = AO;
a1fd562d 926 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 927 break;
928 case TS_IP:
929 b[1] = IP;
a1fd562d 930 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 931 break;
932 case TS_SUSP:
933 b[1] = SUSP;
a1fd562d 934 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 935 break;
936 case TS_EOR:
937 b[1] = EOR;
a1fd562d 938 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 939 break;
940 case TS_EOF:
941 b[1] = xEOF;
a1fd562d 942 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 943 break;
a5f3e637 944 case TS_EOL:
6ee0cb6d 945 /* In BINARY mode, CR-LF becomes just CR -
946 * and without the NUL suffix too. */
656fa244 947 if (telnet->opt_states[o_we_bin.index] == ACTIVE)
6ee0cb6d 948 telnet->bufsize = sk_write(telnet->s, "\r", 1);
656fa244 949 else
950 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
a5f3e637 951 break;
374330e2 952 case TS_SYNCH:
32874aea 953 b[1] = DM;
a1fd562d 954 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
955 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
32874aea 956 break;
684d367c 957 case TS_RECHO:
51470298 958 if (telnet->opt_states[o_echo.index] == INACTIVE ||
959 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
960 telnet->opt_states[o_echo.index] = REQUESTED;
961 send_opt(telnet, o_echo.send, o_echo.option);
684d367c 962 }
963 break;
964 case TS_LECHO:
51470298 965 if (telnet->opt_states[o_echo.index] == ACTIVE) {
966 telnet->opt_states[o_echo.index] = REQUESTED;
967 send_opt(telnet, o_echo.nsend, o_echo.option);
684d367c 968 }
374330e2 969 break;
32874aea 970 case TS_PING:
51470298 971 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
32874aea 972 b[1] = NOP;
a1fd562d 973 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
ec55b220 974 }
32874aea 975 break;
6f2d0cde 976 default:
977 break; /* never heard of it */
374330e2 978 }
979}
980
125105d1 981static const struct telnet_special *telnet_get_specials(void *handle)
982{
983 static const struct telnet_special specials[] = {
984 {"Are You There", TS_AYT},
985 {"Break", TS_BRK},
986 {"Synch", TS_SYNCH},
987 {"Erase Character", TS_EC},
988 {"Erase Line", TS_EL},
989 {"Go Ahead", TS_GA},
990 {"No Operation", TS_NOP},
6f2d0cde 991 {NULL, TS_SEP},
125105d1 992 {"Abort Process", TS_ABORT},
993 {"Abort Output", TS_AO},
994 {"Interrupt Process", TS_IP},
995 {"Suspend Process", TS_SUSP},
6f2d0cde 996 {NULL, TS_SEP},
125105d1 997 {"End Of Record", TS_EOR},
998 {"End Of File", TS_EOF},
6f2d0cde 999 {NULL, TS_EXITMENU}
125105d1 1000 };
1001 return specials;
1002}
1003
51470298 1004static Socket telnet_socket(void *handle)
32874aea 1005{
51470298 1006 Telnet telnet = (Telnet) handle;
1007 return telnet->s;
32874aea 1008}
8ccc75b0 1009
51470298 1010static int telnet_sendok(void *handle)
32874aea 1011{
68a49acb 1012 /* Telnet telnet = (Telnet) handle; */
32874aea 1013 return 1;
1014}
4017be6d 1015
51470298 1016static void telnet_unthrottle(void *handle, int backlog)
5471d09a 1017{
51470298 1018 Telnet telnet = (Telnet) handle;
1019 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
5471d09a 1020}
1021
51470298 1022static int telnet_ldisc(void *handle, int option)
32874aea 1023{
51470298 1024 Telnet telnet = (Telnet) handle;
32874aea 1025 if (option == LD_ECHO)
51470298 1026 return telnet->echoing;
32874aea 1027 if (option == LD_EDIT)
51470298 1028 return telnet->editing;
0965bee0 1029 return FALSE;
1030}
1031
b9d7bcad 1032static void telnet_provide_ldisc(void *handle, void *ldisc)
1033{
1034 Telnet telnet = (Telnet) handle;
1035 telnet->ldisc = ldisc;
1036}
1037
a8327734 1038static void telnet_provide_logctx(void *handle, void *logctx)
1039{
1040 /* This is a stub. */
1041}
1042
51470298 1043static int telnet_exitcode(void *handle)
d8d6c7e5 1044{
0da1a790 1045 Telnet telnet = (Telnet) handle;
1046 if (telnet->s != NULL)
1047 return -1; /* still connected */
1048 else
1049 /* Telnet doesn't transmit exit codes back to the client */
1050 return 0;
d8d6c7e5 1051}
1052
374330e2 1053Backend telnet_backend = {
1054 telnet_init,
fabd1805 1055 telnet_free,
86916870 1056 telnet_reconfig,
374330e2 1057 telnet_send,
5471d09a 1058 telnet_sendbuffer,
374330e2 1059 telnet_size,
4017be6d 1060 telnet_special,
125105d1 1061 telnet_get_specials,
8ccc75b0 1062 telnet_socket,
d8d6c7e5 1063 telnet_exitcode,
97db3be4 1064 telnet_sendok,
0965bee0 1065 telnet_ldisc,
b9d7bcad 1066 telnet_provide_ldisc,
a8327734 1067 telnet_provide_logctx,
5471d09a 1068 telnet_unthrottle,
97db3be4 1069 23
374330e2 1070};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator