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In term_init(), copy stuff out of the conf _before_ calling
[u/mdw/putty] / telnet.c
CommitLineData
eaf1e20a 1/*
2 * Telnet backend.
3 */
4
374330e2 5#include <stdio.h>
6#include <stdlib.h>
374330e2 7
8#include "putty.h"
9
10#ifndef FALSE
11#define FALSE 0
12#endif
13#ifndef TRUE
14#define TRUE 1
15#endif
16
32874aea 17#define IAC 255 /* interpret as command: */
18#define DONT 254 /* you are not to use option */
19#define DO 253 /* please, you use option */
20#define WONT 252 /* I won't use option */
21#define WILL 251 /* I will use option */
22#define SB 250 /* interpret as subnegotiation */
23#define SE 240 /* end sub negotiation */
24
25#define GA 249 /* you may reverse the line */
26#define EL 248 /* erase the current line */
27#define EC 247 /* erase the current character */
28#define AYT 246 /* are you there */
29#define AO 245 /* abort output--but let prog finish */
30#define IP 244 /* interrupt process--permanently */
31#define BREAK 243 /* break */
32#define DM 242 /* data mark--for connect. cleaning */
33#define NOP 241 /* nop */
34#define EOR 239 /* end of record (transparent mode) */
35#define ABORT 238 /* Abort process */
36#define SUSP 237 /* Suspend process */
37#define xEOF 236 /* End of file: EOF is already used... */
38
6196fb7e 39#define TELOPTS(X) \
40 X(BINARY, 0) /* 8-bit data path */ \
41 X(ECHO, 1) /* echo */ \
42 X(RCP, 2) /* prepare to reconnect */ \
43 X(SGA, 3) /* suppress go ahead */ \
44 X(NAMS, 4) /* approximate message size */ \
45 X(STATUS, 5) /* give status */ \
46 X(TM, 6) /* timing mark */ \
47 X(RCTE, 7) /* remote controlled transmission and echo */ \
48 X(NAOL, 8) /* negotiate about output line width */ \
49 X(NAOP, 9) /* negotiate about output page size */ \
50 X(NAOCRD, 10) /* negotiate about CR disposition */ \
51 X(NAOHTS, 11) /* negotiate about horizontal tabstops */ \
52 X(NAOHTD, 12) /* negotiate about horizontal tab disposition */ \
53 X(NAOFFD, 13) /* negotiate about formfeed disposition */ \
54 X(NAOVTS, 14) /* negotiate about vertical tab stops */ \
55 X(NAOVTD, 15) /* negotiate about vertical tab disposition */ \
56 X(NAOLFD, 16) /* negotiate about output LF disposition */ \
57 X(XASCII, 17) /* extended ascic character set */ \
58 X(LOGOUT, 18) /* force logout */ \
59 X(BM, 19) /* byte macro */ \
60 X(DET, 20) /* data entry terminal */ \
61 X(SUPDUP, 21) /* supdup protocol */ \
62 X(SUPDUPOUTPUT, 22) /* supdup output */ \
63 X(SNDLOC, 23) /* send location */ \
64 X(TTYPE, 24) /* terminal type */ \
65 X(EOR, 25) /* end or record */ \
66 X(TUID, 26) /* TACACS user identification */ \
67 X(OUTMRK, 27) /* output marking */ \
68 X(TTYLOC, 28) /* terminal location number */ \
69 X(3270REGIME, 29) /* 3270 regime */ \
70 X(X3PAD, 30) /* X.3 PAD */ \
71 X(NAWS, 31) /* window size */ \
72 X(TSPEED, 32) /* terminal speed */ \
73 X(LFLOW, 33) /* remote flow control */ \
74 X(LINEMODE, 34) /* Linemode option */ \
75 X(XDISPLOC, 35) /* X Display Location */ \
76 X(OLD_ENVIRON, 36) /* Old - Environment variables */ \
77 X(AUTHENTICATION, 37) /* Authenticate */ \
78 X(ENCRYPT, 38) /* Encryption option */ \
79 X(NEW_ENVIRON, 39) /* New - Environment variables */ \
80 X(TN3270E, 40) /* TN3270 enhancements */ \
81 X(XAUTH, 41) \
82 X(CHARSET, 42) /* Character set */ \
83 X(RSP, 43) /* Remote serial port */ \
84 X(COM_PORT_OPTION, 44) /* Com port control */ \
85 X(SLE, 45) /* Suppress local echo */ \
86 X(STARTTLS, 46) /* Start TLS */ \
87 X(KERMIT, 47) /* Automatic Kermit file transfer */ \
88 X(SEND_URL, 48) \
89 X(FORWARD_X, 49) \
90 X(PRAGMA_LOGON, 138) \
91 X(SSPI_LOGON, 139) \
92 X(PRAGMA_HEARTBEAT, 140) \
93 X(EXOPL, 255) /* extended-options-list */
94
95#define telnet_enum(x,y) TELOPT_##x = y,
96enum { TELOPTS(telnet_enum) dummy=0 };
97#undef telnet_enum
32874aea 98
99#define TELQUAL_IS 0 /* option is... */
100#define TELQUAL_SEND 1 /* send option */
101#define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
374330e2 102#define BSD_VAR 1
103#define BSD_VALUE 0
104#define RFC_VAR 0
105#define RFC_VALUE 1
106
107#define CR 13
108#define LF 10
109#define NUL 0
110
656fa244 111#define iswritable(x) \
112 ( (x) != IAC && \
113 (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))
374330e2 114
32874aea 115static char *telopt(int opt)
116{
6196fb7e 117#define telnet_str(x,y) case TELOPT_##x: return #x;
118 switch (opt) {
119 TELOPTS(telnet_str)
120 default:
121 return "<unknown>";
122 }
123#undef telnet_str
374330e2 124}
125
51470298 126static void telnet_size(void *handle, int width, int height);
374330e2 127
128struct Opt {
129 int send; /* what we initially send */
130 int nsend; /* -ve send if requested to stop it */
131 int ack, nak; /* +ve and -ve acknowledgements */
132 int option; /* the option code */
51470298 133 int index; /* index into telnet->opt_states[] */
374330e2 134 enum {
135 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
51470298 136 } initial_state;
137};
138
139enum {
140 OPTINDEX_NAWS,
141 OPTINDEX_TSPEED,
142 OPTINDEX_TTYPE,
143 OPTINDEX_OENV,
144 OPTINDEX_NENV,
145 OPTINDEX_ECHO,
146 OPTINDEX_WE_SGA,
147 OPTINDEX_THEY_SGA,
656fa244 148 OPTINDEX_WE_BIN,
149 OPTINDEX_THEY_BIN,
51470298 150 NUM_OPTS
374330e2 151};
152
51470298 153static const struct Opt o_naws =
154 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
155static const struct Opt o_tspeed =
156 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
157static const struct Opt o_ttype =
158 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
5f95fdf1 159static const struct Opt o_oenv =
160 { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };
161static const struct Opt o_nenv =
162 { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };
51470298 163static const struct Opt o_echo =
164 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
165static const struct Opt o_we_sga =
166 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
167static const struct Opt o_they_sga =
168 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
656fa244 169static const struct Opt o_we_bin =
170 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };
171static const struct Opt o_they_bin =
172 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };
51470298 173
174static const struct Opt *const opts[] = {
374330e2 175 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
656fa244 176 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL
374330e2 177};
178
51470298 179typedef struct telnet_tag {
180 const struct plug_function_table *fn;
181 /* the above field _must_ be first in the structure */
182
183 Socket s;
184
185 void *frontend;
b9d7bcad 186 void *ldisc;
51470298 187 int term_width, term_height;
188
189 int opt_states[NUM_OPTS];
190
191 int echoing, editing;
192 int activated;
193 int bufsize;
194 int in_synch;
195 int sb_opt, sb_len;
a1fd562d 196 unsigned char *sb_buf;
51470298 197 int sb_size;
198
199 enum {
200 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
201 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
202 } state;
203
4a693cfc 204 Conf *conf;
39934deb 205
206 Pinger pinger;
51470298 207} *Telnet;
208
5471d09a 209#define TELNET_MAX_BACKLOG 4096
210
374330e2 211#define SB_DELTA 1024
212
ee00c99a 213static void c_write(Telnet telnet, char *buf, int len)
32874aea 214{
5471d09a 215 int backlog;
ee00c99a 216 backlog = from_backend(telnet->frontend, 0, buf, len);
51470298 217 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
fe50e814 218}
219
a8327734 220static void log_option(Telnet telnet, char *sender, int cmd, int option)
32874aea 221{
57356d63 222 char *buf;
24d7f854 223 /*
224 * The strange-looking "<?""?>" below is there to avoid a
225 * trigraph - a double question mark followed by > maps to a
226 * closing brace character!
227 */
57356d63 228 buf = dupprintf("%s:\t%s %s", sender,
229 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
230 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
231 telopt(option));
a8327734 232 logevent(telnet->frontend, buf);
57356d63 233 sfree(buf);
374330e2 234}
235
51470298 236static void send_opt(Telnet telnet, int cmd, int option)
32874aea 237{
374330e2 238 unsigned char b[3];
239
32874aea 240 b[0] = IAC;
241 b[1] = cmd;
242 b[2] = option;
a1fd562d 243 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);
a8327734 244 log_option(telnet, "client", cmd, option);
374330e2 245}
246
51470298 247static void deactivate_option(Telnet telnet, const struct Opt *o)
32874aea 248{
51470298 249 if (telnet->opt_states[o->index] == REQUESTED ||
250 telnet->opt_states[o->index] == ACTIVE)
251 send_opt(telnet, o->nsend, o->option);
252 telnet->opt_states[o->index] = REALLY_INACTIVE;
374330e2 253}
254
708bbbbe 255/*
256 * Generate side effects of enabling or disabling an option.
257 */
51470298 258static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
32874aea 259{
0965bee0 260 if (o->option == TELOPT_ECHO && o->send == DO)
51470298 261 telnet->echoing = !enabled;
b6c680d4 262 else if (o->option == TELOPT_SGA && o->send == DO)
51470298 263 telnet->editing = !enabled;
b9d7bcad 264 if (telnet->ldisc) /* cause ldisc to notice the change */
265 ldisc_send(telnet->ldisc, NULL, 0, 0);
8faa456c 266
267 /* Ensure we get the minimum options */
51470298 268 if (!telnet->activated) {
269 if (telnet->opt_states[o_echo.index] == INACTIVE) {
270 telnet->opt_states[o_echo.index] = REQUESTED;
271 send_opt(telnet, o_echo.send, o_echo.option);
8faa456c 272 }
51470298 273 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
274 telnet->opt_states[o_we_sga.index] = REQUESTED;
275 send_opt(telnet, o_we_sga.send, o_we_sga.option);
8faa456c 276 }
51470298 277 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
278 telnet->opt_states[o_they_sga.index] = REQUESTED;
279 send_opt(telnet, o_they_sga.send, o_they_sga.option);
8faa456c 280 }
51470298 281 telnet->activated = TRUE;
8faa456c 282 }
708bbbbe 283}
284
51470298 285static void activate_option(Telnet telnet, const struct Opt *o)
32874aea 286{
374330e2 287 if (o->send == WILL && o->option == TELOPT_NAWS)
51470298 288 telnet_size(telnet, telnet->term_width, telnet->term_height);
374330e2 289 if (o->send == WILL &&
290 (o->option == TELOPT_NEW_ENVIRON ||
291 o->option == TELOPT_OLD_ENVIRON)) {
292 /*
293 * We may only have one kind of ENVIRON going at a time.
294 * This is a hack, but who cares.
295 */
51470298 296 deactivate_option(telnet, o->option ==
32874aea 297 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
374330e2 298 }
51470298 299 option_side_effects(telnet, o, 1);
374330e2 300}
301
51470298 302static void refused_option(Telnet telnet, const struct Opt *o)
32874aea 303{
374330e2 304 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
51470298 305 telnet->opt_states[o_oenv.index] == INACTIVE) {
306 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
307 telnet->opt_states[o_oenv.index] = REQUESTED;
374330e2 308 }
51470298 309 option_side_effects(telnet, o, 0);
374330e2 310}
311
51470298 312static void proc_rec_opt(Telnet telnet, int cmd, int option)
32874aea 313{
51470298 314 const struct Opt *const *o;
374330e2 315
a8327734 316 log_option(telnet, "server", cmd, option);
374330e2 317 for (o = opts; *o; o++) {
318 if ((*o)->option == option && (*o)->ack == cmd) {
51470298 319 switch (telnet->opt_states[(*o)->index]) {
374330e2 320 case REQUESTED:
51470298 321 telnet->opt_states[(*o)->index] = ACTIVE;
322 activate_option(telnet, *o);
374330e2 323 break;
324 case ACTIVE:
325 break;
326 case INACTIVE:
51470298 327 telnet->opt_states[(*o)->index] = ACTIVE;
328 send_opt(telnet, (*o)->send, option);
329 activate_option(telnet, *o);
374330e2 330 break;
331 case REALLY_INACTIVE:
51470298 332 send_opt(telnet, (*o)->nsend, option);
374330e2 333 break;
334 }
335 return;
336 } else if ((*o)->option == option && (*o)->nak == cmd) {
51470298 337 switch (telnet->opt_states[(*o)->index]) {
374330e2 338 case REQUESTED:
51470298 339 telnet->opt_states[(*o)->index] = INACTIVE;
340 refused_option(telnet, *o);
374330e2 341 break;
342 case ACTIVE:
51470298 343 telnet->opt_states[(*o)->index] = INACTIVE;
344 send_opt(telnet, (*o)->nsend, option);
345 option_side_effects(telnet, *o, 0);
374330e2 346 break;
347 case INACTIVE:
348 case REALLY_INACTIVE:
349 break;
350 }
351 return;
352 }
353 }
354 /*
355 * If we reach here, the option was one we weren't prepared to
108b0b94 356 * cope with. If the request was positive (WILL or DO), we send
357 * a negative ack to indicate refusal. If the request was
358 * negative (WONT / DONT), we must do nothing.
374330e2 359 */
108b0b94 360 if (cmd == WILL || cmd == DO)
361 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
374330e2 362}
363
51470298 364static void process_subneg(Telnet telnet)
32874aea 365{
4a693cfc 366 unsigned char *b, *p, *q;
367 int var, value, n, bsize;
368 char *e, *eval, *ekey, *user;
374330e2 369
51470298 370 switch (telnet->sb_opt) {
374330e2 371 case TELOPT_TSPEED:
51470298 372 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
57356d63 373 char *logbuf;
4a693cfc 374 char *termspeed = conf_get_str(telnet->conf, CONF_termspeed);
375 b = snewn(20 + strlen(termspeed), unsigned char);
32874aea 376 b[0] = IAC;
377 b[1] = SB;
378 b[2] = TELOPT_TSPEED;
374330e2 379 b[3] = TELQUAL_IS;
4a693cfc 380 strcpy((char *)(b + 4), termspeed);
381 n = 4 + strlen(termspeed);
32874aea 382 b[n] = IAC;
383 b[n + 1] = SE;
a1fd562d 384 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
a8327734 385 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
4a693cfc 386 logbuf = dupprintf("client:\tSB TSPEED IS %s", termspeed);
a8327734 387 logevent(telnet->frontend, logbuf);
57356d63 388 sfree(logbuf);
4a693cfc 389 sfree(b);
374330e2 390 } else
a8327734 391 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
374330e2 392 break;
393 case TELOPT_TTYPE:
51470298 394 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
57356d63 395 char *logbuf;
4a693cfc 396 char *termtype = conf_get_str(telnet->conf, CONF_termtype);
397 b = snewn(20 + strlen(termtype), unsigned char);
32874aea 398 b[0] = IAC;
399 b[1] = SB;
400 b[2] = TELOPT_TTYPE;
374330e2 401 b[3] = TELQUAL_IS;
4a693cfc 402 for (n = 0; termtype[n]; n++)
403 b[n + 4] = (termtype[n] >= 'a' && termtype[n] <= 'z' ?
404 termtype[n] + 'A' - 'a' :
405 termtype[n]);
32874aea 406 b[n + 4] = IAC;
407 b[n + 5] = SE;
a1fd562d 408 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);
32874aea 409 b[n + 4] = 0;
a8327734 410 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
57356d63 411 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
a8327734 412 logevent(telnet->frontend, logbuf);
57356d63 413 sfree(logbuf);
4a693cfc 414 sfree(b);
374330e2 415 } else
a8327734 416 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
374330e2 417 break;
418 case TELOPT_OLD_ENVIRON:
32874aea 419 case TELOPT_NEW_ENVIRON:
51470298 420 p = telnet->sb_buf;
421 q = p + telnet->sb_len;
374330e2 422 if (p < q && *p == TELQUAL_SEND) {
57356d63 423 char *logbuf;
374330e2 424 p++;
57356d63 425 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
a8327734 426 logevent(telnet->frontend, logbuf);
57356d63 427 sfree(logbuf);
51470298 428 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
4f6e3bae 429 if (conf_get_int(telnet->conf, CONF_rfc_environ)) {
374330e2 430 value = RFC_VALUE;
431 var = RFC_VAR;
432 } else {
433 value = BSD_VALUE;
434 var = BSD_VAR;
435 }
436 /*
437 * Try to guess the sense of VAR and VALUE.
438 */
439 while (p < q) {
440 if (*p == RFC_VAR) {
441 value = RFC_VALUE;
442 var = RFC_VAR;
443 } else if (*p == BSD_VAR) {
444 value = BSD_VALUE;
445 var = BSD_VAR;
446 }
447 p++;
448 }
449 } else {
450 /*
451 * With NEW_ENVIRON, the sense of VAR and VALUE
452 * isn't in doubt.
453 */
454 value = RFC_VALUE;
455 var = RFC_VAR;
456 }
4a693cfc 457 bsize = 20;
458 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,
459 NULL, &ekey);
460 eval != NULL;
461 eval = conf_get_str_strs(telnet->conf, CONF_environmt,
462 ekey, &ekey))
463 bsize += strlen(ekey) + strlen(eval) + 2;
464 user = get_remote_username(telnet->conf);
465 if (user)
466 bsize += 6 + strlen(user);
467
468 b = snewn(bsize, unsigned char);
32874aea 469 b[0] = IAC;
470 b[1] = SB;
51470298 471 b[2] = telnet->sb_opt;
374330e2 472 b[3] = TELQUAL_IS;
473 n = 4;
4a693cfc 474 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,
475 NULL, &ekey);
476 eval != NULL;
477 eval = conf_get_str_strs(telnet->conf, CONF_environmt,
478 ekey, &ekey)) {
374330e2 479 b[n++] = var;
4a693cfc 480 for (e = ekey; *e; e++)
481 b[n++] = *e;
374330e2 482 b[n++] = value;
4a693cfc 483 for (e = eval; *e; e++)
484 b[n++] = *e;
374330e2 485 }
4a693cfc 486 if (user) {
487 b[n++] = var;
488 b[n++] = 'U';
489 b[n++] = 'S';
490 b[n++] = 'E';
491 b[n++] = 'R';
492 b[n++] = value;
493 for (e = user; *e; e++)
494 b[n++] = *e;
495 }
496 b[n++] = IAC;
497 b[n++] = SE;
498 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
499 if (n == 6) {
500 logbuf = dupprintf("client:\tSB %s IS <nothing>",
501 telopt(telnet->sb_opt));
471c20b0 502 logevent(telnet->frontend, logbuf);
503 sfree(logbuf);
4a693cfc 504 } else {
505 logbuf = dupprintf("client:\tSB %s IS:",
506 telopt(telnet->sb_opt));
507 logevent(telnet->frontend, logbuf);
508 sfree(logbuf);
509 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,
510 NULL, &ekey);
511 eval != NULL;
512 eval = conf_get_str_strs(telnet->conf, CONF_environmt,
513 ekey, &ekey)) {
514 logbuf = dupprintf("\t%s=%s", ekey, eval);
515 logevent(telnet->frontend, logbuf);
516 sfree(logbuf);
517 }
518 if (user) {
519 logbuf = dupprintf("\tUSER=%s", user);
520 logevent(telnet->frontend, logbuf);
521 sfree(logbuf);
522 }
374330e2 523 }
4a693cfc 524 sfree(b);
525 sfree(user);
374330e2 526 }
527 break;
528 }
529}
530
51470298 531static void do_telnet_read(Telnet telnet, char *buf, int len)
32874aea 532{
ee00c99a 533 char *outbuf = NULL;
534 int outbuflen = 0, outbufsize = 0;
535
536#define ADDTOBUF(c) do { \
537 if (outbuflen >= outbufsize) { \
538 outbufsize = outbuflen + 256; \
539 outbuf = sresize(outbuf, outbufsize, char); \
540 } \
541 outbuf[outbuflen++] = (c); \
542} while (0)
374330e2 543
544 while (len--) {
545 int c = (unsigned char) *buf++;
546
51470298 547 switch (telnet->state) {
887035a5 548 case TOP_LEVEL:
374330e2 549 case SEENCR:
51470298 550 if (c == NUL && telnet->state == SEENCR)
551 telnet->state = TOP_LEVEL;
374330e2 552 else if (c == IAC)
51470298 553 telnet->state = SEENIAC;
374330e2 554 else {
51470298 555 if (!telnet->in_synch)
ee00c99a 556 ADDTOBUF(c);
2f938b83 557
558#if 1
559 /* I can't get the F***ing winsock to insert the urgent IAC
560 * into the right position! Even with SO_OOBINLINE it gives
561 * it to recv too soon. And of course the DM byte (that
562 * arrives in the same packet!) appears several K later!!
563 *
564 * Oh well, we do get the DM in the right place so I'll
565 * just stop hiding on the next 0xf2 and hope for the best.
566 */
32874aea 567 else if (c == DM)
51470298 568 telnet->in_synch = 0;
2f938b83 569#endif
656fa244 570 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)
51470298 571 telnet->state = SEENCR;
374330e2 572 else
51470298 573 telnet->state = TOP_LEVEL;
374330e2 574 }
575 break;
576 case SEENIAC:
32874aea 577 if (c == DO)
51470298 578 telnet->state = SEENDO;
32874aea 579 else if (c == DONT)
51470298 580 telnet->state = SEENDONT;
32874aea 581 else if (c == WILL)
51470298 582 telnet->state = SEENWILL;
32874aea 583 else if (c == WONT)
51470298 584 telnet->state = SEENWONT;
32874aea 585 else if (c == SB)
51470298 586 telnet->state = SEENSB;
2f938b83 587 else if (c == DM) {
51470298 588 telnet->in_synch = 0;
589 telnet->state = TOP_LEVEL;
32874aea 590 } else {
ded38628 591 /* ignore everything else; print it if it's IAC */
592 if (c == IAC) {
ee00c99a 593 ADDTOBUF(c);
ded38628 594 }
51470298 595 telnet->state = TOP_LEVEL;
300d41b0 596 }
374330e2 597 break;
598 case SEENWILL:
51470298 599 proc_rec_opt(telnet, WILL, c);
600 telnet->state = TOP_LEVEL;
374330e2 601 break;
602 case SEENWONT:
51470298 603 proc_rec_opt(telnet, WONT, c);
604 telnet->state = TOP_LEVEL;
374330e2 605 break;
606 case SEENDO:
51470298 607 proc_rec_opt(telnet, DO, c);
608 telnet->state = TOP_LEVEL;
374330e2 609 break;
610 case SEENDONT:
51470298 611 proc_rec_opt(telnet, DONT, c);
612 telnet->state = TOP_LEVEL;
374330e2 613 break;
614 case SEENSB:
51470298 615 telnet->sb_opt = c;
616 telnet->sb_len = 0;
617 telnet->state = SUBNEGOT;
374330e2 618 break;
619 case SUBNEGOT:
620 if (c == IAC)
51470298 621 telnet->state = SUBNEG_IAC;
374330e2 622 else {
32874aea 623 subneg_addchar:
51470298 624 if (telnet->sb_len >= telnet->sb_size) {
51470298 625 telnet->sb_size += SB_DELTA;
3d88e64d 626 telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,
627 unsigned char);
374330e2 628 }
3d88e64d 629 telnet->sb_buf[telnet->sb_len++] = c;
51470298 630 telnet->state = SUBNEGOT; /* in case we came here by goto */
374330e2 631 }
632 break;
633 case SUBNEG_IAC:
634 if (c != SE)
635 goto subneg_addchar; /* yes, it's a hack, I know, but... */
636 else {
51470298 637 process_subneg(telnet);
638 telnet->state = TOP_LEVEL;
374330e2 639 }
640 break;
641 }
642 }
ee00c99a 643
644 if (outbuflen)
645 c_write(telnet, outbuf, outbuflen);
646 sfree(outbuf);
374330e2 647}
648
7555d6a5 649static void telnet_log(Plug plug, int type, SockAddr addr, int port,
650 const char *error_msg, int error_code)
651{
652 Telnet telnet = (Telnet) plug;
653 char addrbuf[256], *msg;
654
655 sk_getaddr(addr, addrbuf, lenof(addrbuf));
656
657 if (type == 0)
658 msg = dupprintf("Connecting to %s port %d", addrbuf, port);
659 else
660 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
661
662 logevent(telnet->frontend, msg);
663}
664
cbe2d68f 665static int telnet_closing(Plug plug, const char *error_msg, int error_code,
32874aea 666 int calling_back)
667{
51470298 668 Telnet telnet = (Telnet) plug;
669
670 if (telnet->s) {
671 sk_close(telnet->s);
672 telnet->s = NULL;
39934deb 673 notify_remote_exit(telnet->frontend);
f3ab576e 674 }
7e78000d 675 if (error_msg) {
a8327734 676 logevent(telnet->frontend, error_msg);
971bcc0a 677 connection_fatal(telnet->frontend, "%s", error_msg);
7555d6a5 678 }
679 /* Otherwise, the remote side closed the connection normally. */
7e78000d 680 return 0;
681}
682
32874aea 683static int telnet_receive(Plug plug, int urgent, char *data, int len)
684{
51470298 685 Telnet telnet = (Telnet) plug;
32874aea 686 if (urgent)
51470298 687 telnet->in_synch = TRUE;
688 do_telnet_read(telnet, data, len);
8df7a775 689 return 1;
690}
691
3ad9d396 692static void telnet_sent(Plug plug, int bufsize)
693{
51470298 694 Telnet telnet = (Telnet) plug;
695 telnet->bufsize = bufsize;
3ad9d396 696}
697
374330e2 698/*
8df7a775 699 * Called to set up the Telnet connection.
374330e2 700 *
701 * Returns an error message, or NULL on success.
702 *
6e1ebb76 703 * Also places the canonical host name into `realhost'. It must be
704 * freed by the caller.
374330e2 705 */
cbe2d68f 706static const char *telnet_init(void *frontend_handle, void **backend_handle,
4a693cfc 707 Conf *conf, char *host, int port,
708 char **realhost, int nodelay, int keepalive)
32874aea 709{
51470298 710 static const struct plug_function_table fn_table = {
7555d6a5 711 telnet_log,
7e78000d 712 telnet_closing,
3ad9d396 713 telnet_receive,
714 telnet_sent
51470298 715 };
8df7a775 716 SockAddr addr;
cbe2d68f 717 const char *err;
51470298 718 Telnet telnet;
4a693cfc 719 char *loghost;
720 int addressfamily;
51470298 721
3d88e64d 722 telnet = snew(struct telnet_tag);
51470298 723 telnet->fn = &fn_table;
4a693cfc 724 telnet->conf = conf_copy(conf);
51470298 725 telnet->s = NULL;
726 telnet->echoing = TRUE;
727 telnet->editing = TRUE;
728 telnet->activated = FALSE;
729 telnet->sb_buf = NULL;
730 telnet->sb_size = 0;
731 telnet->frontend = frontend_handle;
4a693cfc 732 telnet->term_width = conf_get_int(telnet->conf, CONF_width);
733 telnet->term_height = conf_get_int(telnet->conf, CONF_height);
51470298 734 telnet->state = TOP_LEVEL;
cc31ab78 735 telnet->ldisc = NULL;
39934deb 736 telnet->pinger = NULL;
51470298 737 *backend_handle = telnet;
887035a5 738
374330e2 739 /*
740 * Try to find host.
741 */
3ad9d396 742 {
57356d63 743 char *buf;
4a693cfc 744 addressfamily = conf_get_int(telnet->conf, CONF_addressfamily);
05581745 745 buf = dupprintf("Looking up host \"%s\"%s", host,
4a693cfc 746 (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
747 (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
05581745 748 "")));
a8327734 749 logevent(telnet->frontend, buf);
57356d63 750 sfree(buf);
3ad9d396 751 }
4a693cfc 752 addr = name_lookup(host, port, realhost, telnet->conf, addressfamily);
f85e6f6e 753 if ((err = sk_addr_error(addr)) != NULL) {
754 sk_addr_free(addr);
8df7a775 755 return err;
f85e6f6e 756 }
374330e2 757
758 if (port < 0)
759 port = 23; /* default telnet port */
760
761 /*
762 * Open socket.
763 */
51470298 764 telnet->s = new_connection(addr, *realhost, port, 0, 1,
4a693cfc 765 nodelay, keepalive, (Plug) telnet, telnet->conf);
a1fd562d 766 if ((err = sk_socket_error(telnet->s)) != NULL)
8df7a775 767 return err;
374330e2 768
4a693cfc 769 telnet->pinger = pinger_new(telnet->conf, &telnet_backend, telnet);
39934deb 770
374330e2 771 /*
772 * Initialise option states.
773 */
4a693cfc 774 if (conf_get_int(telnet->conf, CONF_passive_telnet)) {
51470298 775 const struct Opt *const *o;
8faa456c 776
777 for (o = opts; *o; o++)
51470298 778 telnet->opt_states[(*o)->index] = INACTIVE;
8faa456c 779 } else {
51470298 780 const struct Opt *const *o;
374330e2 781
51470298 782 for (o = opts; *o; o++) {
783 telnet->opt_states[(*o)->index] = (*o)->initial_state;
784 if (telnet->opt_states[(*o)->index] == REQUESTED)
785 send_opt(telnet, (*o)->send, (*o)->option);
786 }
787 telnet->activated = TRUE;
374330e2 788 }
789
374330e2 790 /*
791 * Set up SYNCH state.
792 */
51470298 793 telnet->in_synch = FALSE;
6f34e365 794
533b1743 795 /*
796 * We can send special commands from the start.
797 */
798 update_specials_menu(telnet->frontend);
799
881da168 800 /*
801 * loghost overrides realhost, if specified.
802 */
4a693cfc 803 loghost = conf_get_str(telnet->conf, CONF_loghost);
804 if (*loghost) {
881da168 805 char *colon;
806
807 sfree(*realhost);
4a693cfc 808 *realhost = dupstr(loghost);
881da168 809 colon = strrchr(*realhost, ':');
810 if (colon) {
811 /*
812 * FIXME: if we ever update this aspect of ssh.c for
813 * IPv6 literal management, this should change in line
814 * with it.
815 */
816 *colon++ = '\0';
817 }
818 }
819
374330e2 820 return NULL;
821}
822
fabd1805 823static void telnet_free(void *handle)
824{
825 Telnet telnet = (Telnet) handle;
826
827 sfree(telnet->sb_buf);
828 if (telnet->s)
829 sk_close(telnet->s);
39934deb 830 if (telnet->pinger)
831 pinger_free(telnet->pinger);
4a693cfc 832 conf_free(telnet->conf);
fabd1805 833 sfree(telnet);
834}
374330e2 835/*
86916870 836 * Reconfigure the Telnet backend. There's no immediate action
837 * necessary, in this backend: we just save the fresh config for
838 * any subsequent negotiations.
839 */
4a693cfc 840static void telnet_reconfig(void *handle, Conf *conf)
86916870 841{
842 Telnet telnet = (Telnet) handle;
4a693cfc 843 pinger_reconfig(telnet->pinger, telnet->conf, conf);
844 conf_free(telnet->conf);
845 telnet->conf = conf_copy(conf);
86916870 846}
847
848/*
374330e2 849 * Called to send data down the Telnet connection.
850 */
51470298 851static int telnet_send(void *handle, char *buf, int len)
32874aea 852{
51470298 853 Telnet telnet = (Telnet) handle;
a1fd562d 854 unsigned char *p, *end;
c85623f9 855 static const unsigned char iac[2] = { IAC, IAC };
856 static const unsigned char cr[2] = { CR, NUL };
a5f3e637 857#if 0
c85623f9 858 static const unsigned char nl[2] = { CR, LF };
a5f3e637 859#endif
374330e2 860
51470298 861 if (telnet->s == NULL)
5471d09a 862 return 0;
374330e2 863
a1fd562d 864 p = (unsigned char *)buf;
865 end = (unsigned char *)(buf + len);
866 while (p < end) {
867 unsigned char *q = p;
374330e2 868
a1fd562d 869 while (p < end && iswritable(*p))
32874aea 870 p++;
a1fd562d 871 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
374330e2 872
a1fd562d 873 while (p < end && !iswritable(*p)) {
51470298 874 telnet->bufsize =
a1fd562d 875 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
374330e2 876 p++;
877 }
878 }
5471d09a 879
51470298 880 return telnet->bufsize;
5471d09a 881}
882
883/*
884 * Called to query the current socket sendability status.
885 */
51470298 886static int telnet_sendbuffer(void *handle)
5471d09a 887{
51470298 888 Telnet telnet = (Telnet) handle;
889 return telnet->bufsize;
374330e2 890}
891
892/*
893 * Called to set the size of the window from Telnet's POV.
894 */
51470298 895static void telnet_size(void *handle, int width, int height)
32874aea 896{
51470298 897 Telnet telnet = (Telnet) handle;
ef41972c 898 unsigned char b[24];
899 int n;
57356d63 900 char *logbuf;
374330e2 901
51470298 902 telnet->term_width = width;
903 telnet->term_height = height;
f278d6f8 904
51470298 905 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
374330e2 906 return;
ef41972c 907 n = 0;
908 b[n++] = IAC;
909 b[n++] = SB;
910 b[n++] = TELOPT_NAWS;
911 b[n++] = telnet->term_width >> 8;
912 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
913 b[n++] = telnet->term_width & 0xFF;
914 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
915 b[n++] = telnet->term_height >> 8;
916 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
917 b[n++] = telnet->term_height & 0xFF;
918 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
919 b[n++] = IAC;
920 b[n++] = SE;
a1fd562d 921 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
57356d63 922 logbuf = dupprintf("client:\tSB NAWS %d,%d",
ef41972c 923 telnet->term_width, telnet->term_height);
a8327734 924 logevent(telnet->frontend, logbuf);
57356d63 925 sfree(logbuf);
374330e2 926}
927
928/*
929 * Send Telnet special codes.
930 */
51470298 931static void telnet_special(void *handle, Telnet_Special code)
32874aea 932{
51470298 933 Telnet telnet = (Telnet) handle;
374330e2 934 unsigned char b[2];
935
51470298 936 if (telnet->s == NULL)
374330e2 937 return;
938
939 b[0] = IAC;
940 switch (code) {
32874aea 941 case TS_AYT:
942 b[1] = AYT;
a1fd562d 943 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 944 break;
945 case TS_BRK:
946 b[1] = BREAK;
a1fd562d 947 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 948 break;
949 case TS_EC:
950 b[1] = EC;
a1fd562d 951 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 952 break;
953 case TS_EL:
954 b[1] = EL;
a1fd562d 955 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 956 break;
957 case TS_GA:
958 b[1] = GA;
a1fd562d 959 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 960 break;
961 case TS_NOP:
962 b[1] = NOP;
a1fd562d 963 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 964 break;
965 case TS_ABORT:
966 b[1] = ABORT;
a1fd562d 967 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 968 break;
969 case TS_AO:
970 b[1] = AO;
a1fd562d 971 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 972 break;
973 case TS_IP:
974 b[1] = IP;
a1fd562d 975 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 976 break;
977 case TS_SUSP:
978 b[1] = SUSP;
a1fd562d 979 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 980 break;
981 case TS_EOR:
982 b[1] = EOR;
a1fd562d 983 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 984 break;
985 case TS_EOF:
986 b[1] = xEOF;
a1fd562d 987 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
32874aea 988 break;
a5f3e637 989 case TS_EOL:
6ee0cb6d 990 /* In BINARY mode, CR-LF becomes just CR -
991 * and without the NUL suffix too. */
656fa244 992 if (telnet->opt_states[o_we_bin.index] == ACTIVE)
6ee0cb6d 993 telnet->bufsize = sk_write(telnet->s, "\r", 1);
656fa244 994 else
995 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
a5f3e637 996 break;
374330e2 997 case TS_SYNCH:
32874aea 998 b[1] = DM;
a1fd562d 999 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
1000 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
32874aea 1001 break;
684d367c 1002 case TS_RECHO:
51470298 1003 if (telnet->opt_states[o_echo.index] == INACTIVE ||
1004 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
1005 telnet->opt_states[o_echo.index] = REQUESTED;
1006 send_opt(telnet, o_echo.send, o_echo.option);
684d367c 1007 }
1008 break;
1009 case TS_LECHO:
51470298 1010 if (telnet->opt_states[o_echo.index] == ACTIVE) {
1011 telnet->opt_states[o_echo.index] = REQUESTED;
1012 send_opt(telnet, o_echo.nsend, o_echo.option);
684d367c 1013 }
374330e2 1014 break;
32874aea 1015 case TS_PING:
51470298 1016 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
32874aea 1017 b[1] = NOP;
a1fd562d 1018 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
ec55b220 1019 }
32874aea 1020 break;
6f2d0cde 1021 default:
1022 break; /* never heard of it */
374330e2 1023 }
1024}
1025
125105d1 1026static const struct telnet_special *telnet_get_specials(void *handle)
1027{
1028 static const struct telnet_special specials[] = {
1029 {"Are You There", TS_AYT},
1030 {"Break", TS_BRK},
1031 {"Synch", TS_SYNCH},
1032 {"Erase Character", TS_EC},
1033 {"Erase Line", TS_EL},
1034 {"Go Ahead", TS_GA},
1035 {"No Operation", TS_NOP},
6f2d0cde 1036 {NULL, TS_SEP},
125105d1 1037 {"Abort Process", TS_ABORT},
1038 {"Abort Output", TS_AO},
1039 {"Interrupt Process", TS_IP},
1040 {"Suspend Process", TS_SUSP},
6f2d0cde 1041 {NULL, TS_SEP},
125105d1 1042 {"End Of Record", TS_EOR},
1043 {"End Of File", TS_EOF},
6f2d0cde 1044 {NULL, TS_EXITMENU}
125105d1 1045 };
1046 return specials;
1047}
1048
6226c939 1049static int telnet_connected(void *handle)
32874aea 1050{
51470298 1051 Telnet telnet = (Telnet) handle;
6226c939 1052 return telnet->s != NULL;
32874aea 1053}
8ccc75b0 1054
51470298 1055static int telnet_sendok(void *handle)
32874aea 1056{
68a49acb 1057 /* Telnet telnet = (Telnet) handle; */
32874aea 1058 return 1;
1059}
4017be6d 1060
51470298 1061static void telnet_unthrottle(void *handle, int backlog)
5471d09a 1062{
51470298 1063 Telnet telnet = (Telnet) handle;
1064 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
5471d09a 1065}
1066
51470298 1067static int telnet_ldisc(void *handle, int option)
32874aea 1068{
51470298 1069 Telnet telnet = (Telnet) handle;
32874aea 1070 if (option == LD_ECHO)
51470298 1071 return telnet->echoing;
32874aea 1072 if (option == LD_EDIT)
51470298 1073 return telnet->editing;
0965bee0 1074 return FALSE;
1075}
1076
b9d7bcad 1077static void telnet_provide_ldisc(void *handle, void *ldisc)
1078{
1079 Telnet telnet = (Telnet) handle;
1080 telnet->ldisc = ldisc;
1081}
1082
a8327734 1083static void telnet_provide_logctx(void *handle, void *logctx)
1084{
1085 /* This is a stub. */
1086}
1087
51470298 1088static int telnet_exitcode(void *handle)
d8d6c7e5 1089{
0da1a790 1090 Telnet telnet = (Telnet) handle;
1091 if (telnet->s != NULL)
1092 return -1; /* still connected */
1093 else
1094 /* Telnet doesn't transmit exit codes back to the client */
1095 return 0;
d8d6c7e5 1096}
1097
f89c3294 1098/*
1099 * cfg_info for Telnet does nothing at all.
1100 */
1101static int telnet_cfg_info(void *handle)
1102{
1103 return 0;
1104}
1105
374330e2 1106Backend telnet_backend = {
1107 telnet_init,
fabd1805 1108 telnet_free,
86916870 1109 telnet_reconfig,
374330e2 1110 telnet_send,
5471d09a 1111 telnet_sendbuffer,
374330e2 1112 telnet_size,
4017be6d 1113 telnet_special,
125105d1 1114 telnet_get_specials,
6226c939 1115 telnet_connected,
d8d6c7e5 1116 telnet_exitcode,
97db3be4 1117 telnet_sendok,
0965bee0 1118 telnet_ldisc,
b9d7bcad 1119 telnet_provide_ldisc,
a8327734 1120 telnet_provide_logctx,
5471d09a 1121 telnet_unthrottle,
f89c3294 1122 telnet_cfg_info,
9e164d82 1123 "telnet",
1124 PROT_TELNET,
97db3be4 1125 23
374330e2 1126};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator