| blob | 8fbe886794053830b32c9142a0f68cf34a5ab9f9 |
1 /*\r
2 * Telnet backend.\r
3 */\r
4 \r
5 #include <stdio.h>\r
6 #include <stdlib.h>\r
7 \r
8 #include "putty.h"\r
9 \r
10 #ifndef FALSE\r
11 #define FALSE 0\r
12 #endif\r
13 #ifndef TRUE\r
14 #define TRUE 1\r
15 #endif\r
16 \r
17 #define IAC 255 /* interpret as command: */\r
18 #define DONT 254 /* you are not to use option */\r
19 #define DO 253 /* please, you use option */\r
20 #define WONT 252 /* I won't use option */\r
21 #define WILL 251 /* I will use option */\r
22 #define SB 250 /* interpret as subnegotiation */\r
23 #define SE 240 /* end sub negotiation */\r
24 \r
25 #define GA 249 /* you may reverse the line */\r
26 #define EL 248 /* erase the current line */\r
27 #define EC 247 /* erase the current character */\r
28 #define AYT 246 /* are you there */\r
29 #define AO 245 /* abort output--but let prog finish */\r
30 #define IP 244 /* interrupt process--permanently */\r
31 #define BREAK 243 /* break */\r
32 #define DM 242 /* data mark--for connect. cleaning */\r
33 #define NOP 241 /* nop */\r
34 #define EOR 239 /* end of record (transparent mode) */\r
35 #define ABORT 238 /* Abort process */\r
36 #define SUSP 237 /* Suspend process */\r
37 #define xEOF 236 /* End of file: EOF is already used... */\r
38 \r
39 #define TELOPTS(X) \\r
40 X(BINARY, 0) /* 8-bit data path */ \\r
41 X(ECHO, 1) /* echo */ \\r
42 X(RCP, 2) /* prepare to reconnect */ \\r
43 X(SGA, 3) /* suppress go ahead */ \\r
44 X(NAMS, 4) /* approximate message size */ \\r
45 X(STATUS, 5) /* give status */ \\r
46 X(TM, 6) /* timing mark */ \\r
47 X(RCTE, 7) /* remote controlled transmission and echo */ \\r
48 X(NAOL, 8) /* negotiate about output line width */ \\r
49 X(NAOP, 9) /* negotiate about output page size */ \\r
50 X(NAOCRD, 10) /* negotiate about CR disposition */ \\r
51 X(NAOHTS, 11) /* negotiate about horizontal tabstops */ \\r
52 X(NAOHTD, 12) /* negotiate about horizontal tab disposition */ \\r
53 X(NAOFFD, 13) /* negotiate about formfeed disposition */ \\r
54 X(NAOVTS, 14) /* negotiate about vertical tab stops */ \\r
55 X(NAOVTD, 15) /* negotiate about vertical tab disposition */ \\r
56 X(NAOLFD, 16) /* negotiate about output LF disposition */ \\r
57 X(XASCII, 17) /* extended ascic character set */ \\r
58 X(LOGOUT, 18) /* force logout */ \\r
59 X(BM, 19) /* byte macro */ \\r
60 X(DET, 20) /* data entry terminal */ \\r
61 X(SUPDUP, 21) /* supdup protocol */ \\r
62 X(SUPDUPOUTPUT, 22) /* supdup output */ \\r
63 X(SNDLOC, 23) /* send location */ \\r
64 X(TTYPE, 24) /* terminal type */ \\r
65 X(EOR, 25) /* end or record */ \\r
66 X(TUID, 26) /* TACACS user identification */ \\r
67 X(OUTMRK, 27) /* output marking */ \\r
68 X(TTYLOC, 28) /* terminal location number */ \\r
69 X(3270REGIME, 29) /* 3270 regime */ \\r
70 X(X3PAD, 30) /* X.3 PAD */ \\r
71 X(NAWS, 31) /* window size */ \\r
72 X(TSPEED, 32) /* terminal speed */ \\r
73 X(LFLOW, 33) /* remote flow control */ \\r
74 X(LINEMODE, 34) /* Linemode option */ \\r
75 X(XDISPLOC, 35) /* X Display Location */ \\r
76 X(OLD_ENVIRON, 36) /* Old - Environment variables */ \\r
77 X(AUTHENTICATION, 37) /* Authenticate */ \\r
78 X(ENCRYPT, 38) /* Encryption option */ \\r
79 X(NEW_ENVIRON, 39) /* New - Environment variables */ \\r
80 X(TN3270E, 40) /* TN3270 enhancements */ \\r
81 X(XAUTH, 41) \\r
82 X(CHARSET, 42) /* Character set */ \\r
83 X(RSP, 43) /* Remote serial port */ \\r
84 X(COM_PORT_OPTION, 44) /* Com port control */ \\r
85 X(SLE, 45) /* Suppress local echo */ \\r
86 X(STARTTLS, 46) /* Start TLS */ \\r
87 X(KERMIT, 47) /* Automatic Kermit file transfer */ \\r
88 X(SEND_URL, 48) \\r
89 X(FORWARD_X, 49) \\r
90 X(PRAGMA_LOGON, 138) \\r
91 X(SSPI_LOGON, 139) \\r
92 X(PRAGMA_HEARTBEAT, 140) \\r
93 X(EXOPL, 255) /* extended-options-list */\r
94 \r
95 #define telnet_enum(x,y) TELOPT_##x = y,\r
96 enum { TELOPTS(telnet_enum) dummy=0 };\r
97 #undef telnet_enum\r
98 \r
99 #define TELQUAL_IS 0 /* option is... */\r
100 #define TELQUAL_SEND 1 /* send option */\r
101 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */\r
102 #define BSD_VAR 1\r
103 #define BSD_VALUE 0\r
104 #define RFC_VAR 0\r
105 #define RFC_VALUE 1\r
106 \r
107 #define CR 13\r
108 #define LF 10\r
109 #define NUL 0\r
110 \r
111 #define iswritable(x) \\r
112 ( (x) != IAC && \\r
113 (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))\r
114 \r
115 static char *telopt(int opt)\r
116 {\r
117 #define telnet_str(x,y) case TELOPT_##x: return #x;\r
118 switch (opt) {\r
119 TELOPTS(telnet_str)\r
120 default:\r
121 return "<unknown>";\r
122 }\r
123 #undef telnet_str\r
124 }\r
125 \r
126 static void telnet_size(void *handle, int width, int height);\r
127 \r
128 struct Opt {\r
129 int send; /* what we initially send */\r
130 int nsend; /* -ve send if requested to stop it */\r
131 int ack, nak; /* +ve and -ve acknowledgements */\r
132 int option; /* the option code */\r
133 int index; /* index into telnet->opt_states[] */\r
134 enum {\r
135 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE\r
136 } initial_state;\r
137 };\r
138 \r
139 enum {\r
140 OPTINDEX_NAWS,\r
141 OPTINDEX_TSPEED,\r
142 OPTINDEX_TTYPE,\r
143 OPTINDEX_OENV,\r
144 OPTINDEX_NENV,\r
145 OPTINDEX_ECHO,\r
146 OPTINDEX_WE_SGA,\r
147 OPTINDEX_THEY_SGA,\r
148 OPTINDEX_WE_BIN,\r
149 OPTINDEX_THEY_BIN,\r
150 NUM_OPTS\r
151 };\r
152 \r
153 static const struct Opt o_naws =\r
154 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };\r
155 static const struct Opt o_tspeed =\r
156 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };\r
157 static const struct Opt o_ttype =\r
158 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };\r
159 static const struct Opt o_oenv =\r
160 { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };\r
161 static const struct Opt o_nenv =\r
162 { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };\r
163 static const struct Opt o_echo =\r
164 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };\r
165 static const struct Opt o_we_sga =\r
166 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };\r
167 static const struct Opt o_they_sga =\r
168 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };\r
169 static const struct Opt o_we_bin =\r
170 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };\r
171 static const struct Opt o_they_bin =\r
172 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };\r
173 \r
174 static const struct Opt *const opts[] = {\r
175 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,\r
176 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL\r
177 };\r
178 \r
179 typedef struct telnet_tag {\r
180 const struct plug_function_table *fn;\r
181 /* the above field _must_ be first in the structure */\r
182 \r
183 Socket s;\r
184 \r
185 void *frontend;\r
186 void *ldisc;\r
187 int term_width, term_height;\r
188 \r
189 int opt_states[NUM_OPTS];\r
190 \r
191 int echoing, editing;\r
192 int activated;\r
193 int bufsize;\r
194 int in_synch;\r
195 int sb_opt, sb_len;\r
196 unsigned char *sb_buf;\r
197 int sb_size;\r
198 \r
199 enum {\r
200 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,\r
201 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR\r
202 } state;\r
203 \r
204 Config cfg;\r
205 \r
206 Pinger pinger;\r
207 } *Telnet;\r
208 \r
209 #define TELNET_MAX_BACKLOG 4096\r
210 \r
211 #define SB_DELTA 1024\r
212 \r
213 static void c_write(Telnet telnet, char *buf, int len)\r
214 {\r
215 int backlog;\r
216 backlog = from_backend(telnet->frontend, 0, buf, len);\r
217 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);\r
218 }\r
219 \r
220 static void log_option(Telnet telnet, char *sender, int cmd, int option)\r
221 {\r
222 char *buf;\r
223 /*\r
224 * The strange-looking "<?""?>" below is there to avoid a\r
225 * trigraph - a double question mark followed by > maps to a\r
226 * closing brace character!\r
227 */\r
228 buf = dupprintf("%s:\t%s %s", sender,\r
229 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :\r
230 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),\r
231 telopt(option));\r
232 logevent(telnet->frontend, buf);\r
233 sfree(buf);\r
234 }\r
235 \r
236 static void send_opt(Telnet telnet, int cmd, int option)\r
237 {\r
238 unsigned char b[3];\r
239 \r
240 b[0] = IAC;\r
241 b[1] = cmd;\r
242 b[2] = option;\r
243 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);\r
244 log_option(telnet, "client", cmd, option);\r
245 }\r
246 \r
247 static void deactivate_option(Telnet telnet, const struct Opt *o)\r
248 {\r
249 if (telnet->opt_states[o->index] == REQUESTED ||\r
250 telnet->opt_states[o->index] == ACTIVE)\r
251 send_opt(telnet, o->nsend, o->option);\r
252 telnet->opt_states[o->index] = REALLY_INACTIVE;\r
253 }\r
254 \r
255 /*\r
256 * Generate side effects of enabling or disabling an option.\r
257 */\r
258 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)\r
259 {\r
260 if (o->option == TELOPT_ECHO && o->send == DO)\r
261 telnet->echoing = !enabled;\r
262 else if (o->option == TELOPT_SGA && o->send == DO)\r
263 telnet->editing = !enabled;\r
264 if (telnet->ldisc) /* cause ldisc to notice the change */\r
265 ldisc_send(telnet->ldisc, NULL, 0, 0);\r
266 \r
267 /* Ensure we get the minimum options */\r
268 if (!telnet->activated) {\r
269 if (telnet->opt_states[o_echo.index] == INACTIVE) {\r
270 telnet->opt_states[o_echo.index] = REQUESTED;\r
271 send_opt(telnet, o_echo.send, o_echo.option);\r
272 }\r
273 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {\r
274 telnet->opt_states[o_we_sga.index] = REQUESTED;\r
275 send_opt(telnet, o_we_sga.send, o_we_sga.option);\r
276 }\r
277 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {\r
278 telnet->opt_states[o_they_sga.index] = REQUESTED;\r
279 send_opt(telnet, o_they_sga.send, o_they_sga.option);\r
280 }\r
281 telnet->activated = TRUE;\r
282 }\r
283 }\r
284 \r
285 static void activate_option(Telnet telnet, const struct Opt *o)\r
286 {\r
287 if (o->send == WILL && o->option == TELOPT_NAWS)\r
288 telnet_size(telnet, telnet->term_width, telnet->term_height);\r
289 if (o->send == WILL &&\r
290 (o->option == TELOPT_NEW_ENVIRON ||\r
291 o->option == TELOPT_OLD_ENVIRON)) {\r
292 /*\r
293 * We may only have one kind of ENVIRON going at a time.\r
294 * This is a hack, but who cares.\r
295 */\r
296 deactivate_option(telnet, o->option ==\r
297 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);\r
298 }\r
299 option_side_effects(telnet, o, 1);\r
300 }\r
301 \r
302 static void refused_option(Telnet telnet, const struct Opt *o)\r
303 {\r
304 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&\r
305 telnet->opt_states[o_oenv.index] == INACTIVE) {\r
306 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);\r
307 telnet->opt_states[o_oenv.index] = REQUESTED;\r
308 }\r
309 option_side_effects(telnet, o, 0);\r
310 }\r
311 \r
312 static void proc_rec_opt(Telnet telnet, int cmd, int option)\r
313 {\r
314 const struct Opt *const *o;\r
315 \r
316 log_option(telnet, "server", cmd, option);\r
317 for (o = opts; *o; o++) {\r
318 if ((*o)->option == option && (*o)->ack == cmd) {\r
319 switch (telnet->opt_states[(*o)->index]) {\r
320 case REQUESTED:\r
321 telnet->opt_states[(*o)->index] = ACTIVE;\r
322 activate_option(telnet, *o);\r
323 break;\r
324 case ACTIVE:\r
325 break;\r
326 case INACTIVE:\r
327 telnet->opt_states[(*o)->index] = ACTIVE;\r
328 send_opt(telnet, (*o)->send, option);\r
329 activate_option(telnet, *o);\r
330 break;\r
331 case REALLY_INACTIVE:\r
332 send_opt(telnet, (*o)->nsend, option);\r
333 break;\r
334 }\r
335 return;\r
336 } else if ((*o)->option == option && (*o)->nak == cmd) {\r
337 switch (telnet->opt_states[(*o)->index]) {\r
338 case REQUESTED:\r
339 telnet->opt_states[(*o)->index] = INACTIVE;\r
340 refused_option(telnet, *o);\r
341 break;\r
342 case ACTIVE:\r
343 telnet->opt_states[(*o)->index] = INACTIVE;\r
344 send_opt(telnet, (*o)->nsend, option);\r
345 option_side_effects(telnet, *o, 0);\r
346 break;\r
347 case INACTIVE:\r
348 case REALLY_INACTIVE:\r
349 break;\r
350 }\r
351 return;\r
352 }\r
353 }\r
354 /*\r
355 * If we reach here, the option was one we weren't prepared to\r
356 * cope with. If the request was positive (WILL or DO), we send\r
357 * a negative ack to indicate refusal. If the request was\r
358 * negative (WONT / DONT), we must do nothing.\r
359 */\r
360 if (cmd == WILL || cmd == DO)\r
361 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);\r
362 }\r
363 \r
364 static void process_subneg(Telnet telnet)\r
365 {\r
366 unsigned char b[2048], *p, *q;\r
367 int var, value, n;\r
368 char *e;\r
369 \r
370 switch (telnet->sb_opt) {\r
371 case TELOPT_TSPEED:\r
372 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {\r
373 char *logbuf;\r
374 b[0] = IAC;\r
375 b[1] = SB;\r
376 b[2] = TELOPT_TSPEED;\r
377 b[3] = TELQUAL_IS;\r
378 strcpy((char *)(b + 4), telnet->cfg.termspeed);\r
379 n = 4 + strlen(telnet->cfg.termspeed);\r
380 b[n] = IAC;\r
381 b[n + 1] = SE;\r
382 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);\r
383 logevent(telnet->frontend, "server:\tSB TSPEED SEND");\r
384 logbuf = dupprintf("client:\tSB TSPEED IS %s", telnet->cfg.termspeed);\r
385 logevent(telnet->frontend, logbuf);\r
386 sfree(logbuf);\r
387 } else\r
388 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");\r
389 break;\r
390 case TELOPT_TTYPE:\r
391 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {\r
392 char *logbuf;\r
393 b[0] = IAC;\r
394 b[1] = SB;\r
395 b[2] = TELOPT_TTYPE;\r
396 b[3] = TELQUAL_IS;\r
397 for (n = 0; telnet->cfg.termtype[n]; n++)\r
398 b[n + 4] = (telnet->cfg.termtype[n] >= 'a'\r
399 && telnet->cfg.termtype[n] <=\r
400 'z' ? telnet->cfg.termtype[n] + 'A' -\r
401 'a' : telnet->cfg.termtype[n]);\r
402 b[n + 4] = IAC;\r
403 b[n + 5] = SE;\r
404 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);\r
405 b[n + 4] = 0;\r
406 logevent(telnet->frontend, "server:\tSB TTYPE SEND");\r
407 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);\r
408 logevent(telnet->frontend, logbuf);\r
409 sfree(logbuf);\r
410 } else\r
411 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");\r
412 break;\r
413 case TELOPT_OLD_ENVIRON:\r
414 case TELOPT_NEW_ENVIRON:\r
415 p = telnet->sb_buf;\r
416 q = p + telnet->sb_len;\r
417 if (p < q && *p == TELQUAL_SEND) {\r
418 char *logbuf;\r
419 p++;\r
420 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));\r
421 logevent(telnet->frontend, logbuf);\r
422 sfree(logbuf);\r
423 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {\r
424 if (telnet->cfg.rfc_environ) {\r
425 value = RFC_VALUE;\r
426 var = RFC_VAR;\r
427 } else {\r
428 value = BSD_VALUE;\r
429 var = BSD_VAR;\r
430 }\r
431 /*\r
432 * Try to guess the sense of VAR and VALUE.\r
433 */\r
434 while (p < q) {\r
435 if (*p == RFC_VAR) {\r
436 value = RFC_VALUE;\r
437 var = RFC_VAR;\r
438 } else if (*p == BSD_VAR) {\r
439 value = BSD_VALUE;\r
440 var = BSD_VAR;\r
441 }\r
442 p++;\r
443 }\r
444 } else {\r
445 /*\r
446 * With NEW_ENVIRON, the sense of VAR and VALUE\r
447 * isn't in doubt.\r
448 */\r
449 value = RFC_VALUE;\r
450 var = RFC_VAR;\r
451 }\r
452 b[0] = IAC;\r
453 b[1] = SB;\r
454 b[2] = telnet->sb_opt;\r
455 b[3] = TELQUAL_IS;\r
456 n = 4;\r
457 e = telnet->cfg.environmt;\r
458 while (*e) {\r
459 b[n++] = var;\r
460 while (*e && *e != '\t')\r
461 b[n++] = *e++;\r
462 if (*e == '\t')\r
463 e++;\r
464 b[n++] = value;\r
465 while (*e)\r
466 b[n++] = *e++;\r
467 e++;\r
468 }\r
469 {\r
470 char user[sizeof(telnet->cfg.username)];\r
471 (void) get_remote_username(&telnet->cfg, user, sizeof(user));\r
472 if (*user) {\r
473 b[n++] = var;\r
474 b[n++] = 'U';\r
475 b[n++] = 'S';\r
476 b[n++] = 'E';\r
477 b[n++] = 'R';\r
478 b[n++] = value;\r
479 e = user;\r
480 while (*e)\r
481 b[n++] = *e++;\r
482 }\r
483 b[n++] = IAC;\r
484 b[n++] = SE;\r
485 telnet->bufsize = sk_write(telnet->s, (char *)b, n);\r
486 logbuf = dupprintf("client:\tSB %s IS %s%s%s%s",\r
487 telopt(telnet->sb_opt),\r
488 *user ? "USER=" : "",\r
489 user,\r
490 *user ? " " : "",\r
491 n == 6 ? "<nothing>" :\r
492 (*telnet->cfg.environmt ? "<stuff>" : ""));\r
493 logevent(telnet->frontend, logbuf);\r
494 sfree(logbuf);\r
495 }\r
496 }\r
497 break;\r
498 }\r
499 }\r
500 \r
501 static void do_telnet_read(Telnet telnet, char *buf, int len)\r
502 {\r
503 char *outbuf = NULL;\r
504 int outbuflen = 0, outbufsize = 0;\r
505 \r
506 #define ADDTOBUF(c) do { \\r
507 if (outbuflen >= outbufsize) { \\r
508 outbufsize = outbuflen + 256; \\r
509 outbuf = sresize(outbuf, outbufsize, char); \\r
510 } \\r
511 outbuf[outbuflen++] = (c); \\r
512 } while (0)\r
513 \r
514 while (len--) {\r
515 int c = (unsigned char) *buf++;\r
516 \r
517 switch (telnet->state) {\r
518 case TOP_LEVEL:\r
519 case SEENCR:\r
520 if (c == NUL && telnet->state == SEENCR)\r
521 telnet->state = TOP_LEVEL;\r
522 else if (c == IAC)\r
523 telnet->state = SEENIAC;\r
524 else {\r
525 if (!telnet->in_synch)\r
526 ADDTOBUF(c);\r
527 \r
528 #if 1\r
529 /* I can't get the F***ing winsock to insert the urgent IAC\r
530 * into the right position! Even with SO_OOBINLINE it gives\r
531 * it to recv too soon. And of course the DM byte (that\r
532 * arrives in the same packet!) appears several K later!!\r
533 *\r
534 * Oh well, we do get the DM in the right place so I'll\r
535 * just stop hiding on the next 0xf2 and hope for the best.\r
536 */\r
537 else if (c == DM)\r
538 telnet->in_synch = 0;\r
539 #endif\r
540 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)\r
541 telnet->state = SEENCR;\r
542 else\r
543 telnet->state = TOP_LEVEL;\r
544 }\r
545 break;\r
546 case SEENIAC:\r
547 if (c == DO)\r
548 telnet->state = SEENDO;\r
549 else if (c == DONT)\r
550 telnet->state = SEENDONT;\r
551 else if (c == WILL)\r
552 telnet->state = SEENWILL;\r
553 else if (c == WONT)\r
554 telnet->state = SEENWONT;\r
555 else if (c == SB)\r
556 telnet->state = SEENSB;\r
557 else if (c == DM) {\r
558 telnet->in_synch = 0;\r
559 telnet->state = TOP_LEVEL;\r
560 } else {\r
561 /* ignore everything else; print it if it's IAC */\r
562 if (c == IAC) {\r
563 ADDTOBUF(c);\r
564 }\r
565 telnet->state = TOP_LEVEL;\r
566 }\r
567 break;\r
568 case SEENWILL:\r
569 proc_rec_opt(telnet, WILL, c);\r
570 telnet->state = TOP_LEVEL;\r
571 break;\r
572 case SEENWONT:\r
573 proc_rec_opt(telnet, WONT, c);\r
574 telnet->state = TOP_LEVEL;\r
575 break;\r
576 case SEENDO:\r
577 proc_rec_opt(telnet, DO, c);\r
578 telnet->state = TOP_LEVEL;\r
579 break;\r
580 case SEENDONT:\r
581 proc_rec_opt(telnet, DONT, c);\r
582 telnet->state = TOP_LEVEL;\r
583 break;\r
584 case SEENSB:\r
585 telnet->sb_opt = c;\r
586 telnet->sb_len = 0;\r
587 telnet->state = SUBNEGOT;\r
588 break;\r
589 case SUBNEGOT:\r
590 if (c == IAC)\r
591 telnet->state = SUBNEG_IAC;\r
592 else {\r
593 subneg_addchar:\r
594 if (telnet->sb_len >= telnet->sb_size) {\r
595 telnet->sb_size += SB_DELTA;\r
596 telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,\r
597 unsigned char);\r
598 }\r
599 telnet->sb_buf[telnet->sb_len++] = c;\r
600 telnet->state = SUBNEGOT; /* in case we came here by goto */\r
601 }\r
602 break;\r
603 case SUBNEG_IAC:\r
604 if (c != SE)\r
605 goto subneg_addchar; /* yes, it's a hack, I know, but... */\r
606 else {\r
607 process_subneg(telnet);\r
608 telnet->state = TOP_LEVEL;\r
609 }\r
610 break;\r
611 }\r
612 }\r
613 \r
614 if (outbuflen)\r
615 c_write(telnet, outbuf, outbuflen);\r
616 sfree(outbuf);\r
617 }\r
618 \r
619 static void telnet_log(Plug plug, int type, SockAddr addr, int port,\r
620 const char *error_msg, int error_code)\r
621 {\r
622 Telnet telnet = (Telnet) plug;\r
623 char addrbuf[256], *msg;\r
624 \r
625 sk_getaddr(addr, addrbuf, lenof(addrbuf));\r
626 \r
627 if (type == 0)\r
628 msg = dupprintf("Connecting to %s port %d", addrbuf, port);\r
629 else\r
630 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);\r
631 \r
632 logevent(telnet->frontend, msg);\r
633 }\r
634 \r
635 static int telnet_closing(Plug plug, const char *error_msg, int error_code,\r
636 int calling_back)\r
637 {\r
638 Telnet telnet = (Telnet) plug;\r
639 \r
640 if (telnet->s) {\r
641 sk_close(telnet->s);\r
642 telnet->s = NULL;\r
643 notify_remote_exit(telnet->frontend);\r
644 }\r
645 if (error_msg) {\r
646 logevent(telnet->frontend, error_msg);\r
647 connection_fatal(telnet->frontend, "%s", error_msg);\r
648 }\r
649 /* Otherwise, the remote side closed the connection normally. */\r
650 return 0;\r
651 }\r
652 \r
653 static int telnet_receive(Plug plug, int urgent, char *data, int len)\r
654 {\r
655 Telnet telnet = (Telnet) plug;\r
656 if (urgent)\r
657 telnet->in_synch = TRUE;\r
658 do_telnet_read(telnet, data, len);\r
659 return 1;\r
660 }\r
661 \r
662 static void telnet_sent(Plug plug, int bufsize)\r
663 {\r
664 Telnet telnet = (Telnet) plug;\r
665 telnet->bufsize = bufsize;\r
666 }\r
667 \r
668 /*\r
669 * Called to set up the Telnet connection.\r
670 *\r
671 * Returns an error message, or NULL on success.\r
672 *\r
673 * Also places the canonical host name into `realhost'. It must be\r
674 * freed by the caller.\r
675 */\r
676 static const char *telnet_init(void *frontend_handle, void **backend_handle,\r
677 Config *cfg,\r
678 char *host, int port, char **realhost,\r
679 int nodelay, int keepalive)\r
680 {\r
681 static const struct plug_function_table fn_table = {\r
682 telnet_log,\r
683 telnet_closing,\r
684 telnet_receive,\r
685 telnet_sent\r
686 };\r
687 SockAddr addr;\r
688 const char *err;\r
689 Telnet telnet;\r
690 \r
691 telnet = snew(struct telnet_tag);\r
692 telnet->fn = &fn_table;\r
693 telnet->cfg = *cfg; /* STRUCTURE COPY */\r
694 telnet->s = NULL;\r
695 telnet->echoing = TRUE;\r
696 telnet->editing = TRUE;\r
697 telnet->activated = FALSE;\r
698 telnet->sb_buf = NULL;\r
699 telnet->sb_size = 0;\r
700 telnet->frontend = frontend_handle;\r
701 telnet->term_width = telnet->cfg.width;\r
702 telnet->term_height = telnet->cfg.height;\r
703 telnet->state = TOP_LEVEL;\r
704 telnet->ldisc = NULL;\r
705 telnet->pinger = NULL;\r
706 *backend_handle = telnet;\r
707 \r
708 /*\r
709 * Try to find host.\r
710 */\r
711 {\r
712 char *buf;\r
713 buf = dupprintf("Looking up host \"%s\"%s", host,\r
714 (cfg->addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :\r
715 (cfg->addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :\r
716 "")));\r
717 logevent(telnet->frontend, buf);\r
718 sfree(buf);\r
719 }\r
720 addr = name_lookup(host, port, realhost, &telnet->cfg, cfg->addressfamily);\r
721 if ((err = sk_addr_error(addr)) != NULL) {\r
722 sk_addr_free(addr);\r
723 return err;\r
724 }\r
725 \r
726 if (port < 0)\r
727 port = 23; /* default telnet port */\r
728 \r
729 /*\r
730 * Open socket.\r
731 */\r
732 telnet->s = new_connection(addr, *realhost, port, 0, 1,\r
733 nodelay, keepalive, (Plug) telnet, &telnet->cfg);\r
734 if ((err = sk_socket_error(telnet->s)) != NULL)\r
735 return err;\r
736 \r
737 telnet->pinger = pinger_new(&telnet->cfg, &telnet_backend, telnet);\r
738 \r
739 /*\r
740 * Initialise option states.\r
741 */\r
742 if (telnet->cfg.passive_telnet) {\r
743 const struct Opt *const *o;\r
744 \r
745 for (o = opts; *o; o++)\r
746 telnet->opt_states[(*o)->index] = INACTIVE;\r
747 } else {\r
748 const struct Opt *const *o;\r
749 \r
750 for (o = opts; *o; o++) {\r
751 telnet->opt_states[(*o)->index] = (*o)->initial_state;\r
752 if (telnet->opt_states[(*o)->index] == REQUESTED)\r
753 send_opt(telnet, (*o)->send, (*o)->option);\r
754 }\r
755 telnet->activated = TRUE;\r
756 }\r
757 \r
758 /*\r
759 * Set up SYNCH state.\r
760 */\r
761 telnet->in_synch = FALSE;\r
762 \r
763 /*\r
764 * We can send special commands from the start.\r
765 */\r
766 update_specials_menu(telnet->frontend);\r
767 \r
768 /*\r
769 * loghost overrides realhost, if specified.\r
770 */\r
771 if (*telnet->cfg.loghost) {\r
772 char *colon;\r
773 \r
774 sfree(*realhost);\r
775 *realhost = dupstr(telnet->cfg.loghost);\r
776 colon = strrchr(*realhost, ':');\r
777 if (colon) {\r
778 /*\r
779 * FIXME: if we ever update this aspect of ssh.c for\r
780 * IPv6 literal management, this should change in line\r
781 * with it.\r
782 */\r
783 *colon++ = '\0';\r
784 }\r
785 }\r
786 \r
787 return NULL;\r
788 }\r
789 \r
790 static void telnet_free(void *handle)\r
791 {\r
792 Telnet telnet = (Telnet) handle;\r
793 \r
794 sfree(telnet->sb_buf);\r
795 if (telnet->s)\r
796 sk_close(telnet->s);\r
797 if (telnet->pinger)\r
798 pinger_free(telnet->pinger);\r
799 sfree(telnet);\r
800 }\r
801 /*\r
802 * Reconfigure the Telnet backend. There's no immediate action\r
803 * necessary, in this backend: we just save the fresh config for\r
804 * any subsequent negotiations.\r
805 */\r
806 static void telnet_reconfig(void *handle, Config *cfg)\r
807 {\r
808 Telnet telnet = (Telnet) handle;\r
809 pinger_reconfig(telnet->pinger, &telnet->cfg, cfg);\r
810 telnet->cfg = *cfg; /* STRUCTURE COPY */\r
811 }\r
812 \r
813 /*\r
814 * Called to send data down the Telnet connection.\r
815 */\r
816 static int telnet_send(void *handle, char *buf, int len)\r
817 {\r
818 Telnet telnet = (Telnet) handle;\r
819 unsigned char *p, *end;\r
820 static const unsigned char iac[2] = { IAC, IAC };\r
821 static const unsigned char cr[2] = { CR, NUL };\r
822 #if 0\r
823 static const unsigned char nl[2] = { CR, LF };\r
824 #endif\r
825 \r
826 if (telnet->s == NULL)\r
827 return 0;\r
828 \r
829 p = (unsigned char *)buf;\r
830 end = (unsigned char *)(buf + len);\r
831 while (p < end) {\r
832 unsigned char *q = p;\r
833 \r
834 while (p < end && iswritable(*p))\r
835 p++;\r
836 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);\r
837 \r
838 while (p < end && !iswritable(*p)) {\r
839 telnet->bufsize = \r
840 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);\r
841 p++;\r
842 }\r
843 }\r
844 \r
845 return telnet->bufsize;\r
846 }\r
847 \r
848 /*\r
849 * Called to query the current socket sendability status.\r
850 */\r
851 static int telnet_sendbuffer(void *handle)\r
852 {\r
853 Telnet telnet = (Telnet) handle;\r
854 return telnet->bufsize;\r
855 }\r
856 \r
857 /*\r
858 * Called to set the size of the window from Telnet's POV.\r
859 */\r
860 static void telnet_size(void *handle, int width, int height)\r
861 {\r
862 Telnet telnet = (Telnet) handle;\r
863 unsigned char b[24];\r
864 int n;\r
865 char *logbuf;\r
866 \r
867 telnet->term_width = width;\r
868 telnet->term_height = height;\r
869 \r
870 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)\r
871 return;\r
872 n = 0;\r
873 b[n++] = IAC;\r
874 b[n++] = SB;\r
875 b[n++] = TELOPT_NAWS;\r
876 b[n++] = telnet->term_width >> 8;\r
877 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
878 b[n++] = telnet->term_width & 0xFF;\r
879 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
880 b[n++] = telnet->term_height >> 8;\r
881 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
882 b[n++] = telnet->term_height & 0xFF;\r
883 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
884 b[n++] = IAC;\r
885 b[n++] = SE;\r
886 telnet->bufsize = sk_write(telnet->s, (char *)b, n);\r
887 logbuf = dupprintf("client:\tSB NAWS %d,%d",\r
888 telnet->term_width, telnet->term_height);\r
889 logevent(telnet->frontend, logbuf);\r
890 sfree(logbuf);\r
891 }\r
892 \r
893 /*\r
894 * Send Telnet special codes.\r
895 */\r
896 static void telnet_special(void *handle, Telnet_Special code)\r
897 {\r
898 Telnet telnet = (Telnet) handle;\r
899 unsigned char b[2];\r
900 \r
901 if (telnet->s == NULL)\r
902 return;\r
903 \r
904 b[0] = IAC;\r
905 switch (code) {\r
906 case TS_AYT:\r
907 b[1] = AYT;\r
908 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
909 break;\r
910 case TS_BRK:\r
911 b[1] = BREAK;\r
912 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
913 break;\r
914 case TS_EC:\r
915 b[1] = EC;\r
916 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
917 break;\r
918 case TS_EL:\r
919 b[1] = EL;\r
920 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
921 break;\r
922 case TS_GA:\r
923 b[1] = GA;\r
924 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
925 break;\r
926 case TS_NOP:\r
927 b[1] = NOP;\r
928 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
929 break;\r
930 case TS_ABORT:\r
931 b[1] = ABORT;\r
932 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
933 break;\r
934 case TS_AO:\r
935 b[1] = AO;\r
936 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
937 break;\r
938 case TS_IP:\r
939 b[1] = IP;\r
940 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
941 break;\r
942 case TS_SUSP:\r
943 b[1] = SUSP;\r
944 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
945 break;\r
946 case TS_EOR:\r
947 b[1] = EOR;\r
948 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
949 break;\r
950 case TS_EOF:\r
951 b[1] = xEOF;\r
952 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
953 break;\r
954 case TS_EOL:\r
955 /* In BINARY mode, CR-LF becomes just CR -\r
956 * and without the NUL suffix too. */\r
957 if (telnet->opt_states[o_we_bin.index] == ACTIVE)\r
958 telnet->bufsize = sk_write(telnet->s, "\r", 1);\r
959 else\r
960 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);\r
961 break;\r
962 case TS_SYNCH:\r
963 b[1] = DM;\r
964 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);\r
965 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);\r
966 break;\r
967 case TS_RECHO:\r
968 if (telnet->opt_states[o_echo.index] == INACTIVE ||\r
969 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {\r
970 telnet->opt_states[o_echo.index] = REQUESTED;\r
971 send_opt(telnet, o_echo.send, o_echo.option);\r
972 }\r
973 break;\r
974 case TS_LECHO:\r
975 if (telnet->opt_states[o_echo.index] == ACTIVE) {\r
976 telnet->opt_states[o_echo.index] = REQUESTED;\r
977 send_opt(telnet, o_echo.nsend, o_echo.option);\r
978 }\r
979 break;\r
980 case TS_PING:\r
981 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {\r
982 b[1] = NOP;\r
983 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
984 }\r
985 break;\r
986 default:\r
987 break; /* never heard of it */\r
988 }\r
989 }\r
990 \r
991 static const struct telnet_special *telnet_get_specials(void *handle)\r
992 {\r
993 static const struct telnet_special specials[] = {\r
994 {"Are You There", TS_AYT},\r
995 {"Break", TS_BRK},\r
996 {"Synch", TS_SYNCH},\r
997 {"Erase Character", TS_EC},\r
998 {"Erase Line", TS_EL},\r
999 {"Go Ahead", TS_GA},\r
1000 {"No Operation", TS_NOP},\r
1001 {NULL, TS_SEP},\r
1002 {"Abort Process", TS_ABORT},\r
1003 {"Abort Output", TS_AO},\r
1004 {"Interrupt Process", TS_IP},\r
1005 {"Suspend Process", TS_SUSP},\r
1006 {NULL, TS_SEP},\r
1007 {"End Of Record", TS_EOR},\r
1008 {"End Of File", TS_EOF},\r
1009 {NULL, TS_EXITMENU}\r
1010 };\r
1011 return specials;\r
1012 }\r
1013 \r
1014 static int telnet_connected(void *handle)\r
1015 {\r
1016 Telnet telnet = (Telnet) handle;\r
1017 return telnet->s != NULL;\r
1018 }\r
1019 \r
1020 static int telnet_sendok(void *handle)\r
1021 {\r
1022 /* Telnet telnet = (Telnet) handle; */\r
1023 return 1;\r
1024 }\r
1025 \r
1026 static void telnet_unthrottle(void *handle, int backlog)\r
1027 {\r
1028 Telnet telnet = (Telnet) handle;\r
1029 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);\r
1030 }\r
1031 \r
1032 static int telnet_ldisc(void *handle, int option)\r
1033 {\r
1034 Telnet telnet = (Telnet) handle;\r
1035 if (option == LD_ECHO)\r
1036 return telnet->echoing;\r
1037 if (option == LD_EDIT)\r
1038 return telnet->editing;\r
1039 return FALSE;\r
1040 }\r
1041 \r
1042 static void telnet_provide_ldisc(void *handle, void *ldisc)\r
1043 {\r
1044 Telnet telnet = (Telnet) handle;\r
1045 telnet->ldisc = ldisc;\r
1046 }\r
1047 \r
1048 static void telnet_provide_logctx(void *handle, void *logctx)\r
1049 {\r
1050 /* This is a stub. */\r
1051 }\r
1052 \r
1053 static int telnet_exitcode(void *handle)\r
1054 {\r
1055 Telnet telnet = (Telnet) handle;\r
1056 if (telnet->s != NULL)\r
1057 return -1; /* still connected */\r
1058 else\r
1059 /* Telnet doesn't transmit exit codes back to the client */\r
1060 return 0;\r
1061 }\r
1062 \r
1063 /*\r
1064 * cfg_info for Telnet does nothing at all.\r
1065 */\r
1066 static int telnet_cfg_info(void *handle)\r
1067 {\r
1068 return 0;\r
1069 }\r
1070 \r
1071 Backend telnet_backend = {\r
1072 telnet_init,\r
1073 telnet_free,\r
1074 telnet_reconfig,\r
1075 telnet_send,\r
1076 telnet_sendbuffer,\r
1077 telnet_size,\r
1078 telnet_special,\r
1079 telnet_get_specials,\r
1080 telnet_connected,\r
1081 telnet_exitcode,\r
1082 telnet_sendok,\r
1083 telnet_ldisc,\r
1084 telnet_provide_ldisc,\r
1085 telnet_provide_logctx,\r
1086 telnet_unthrottle,\r
1087 telnet_cfg_info,\r
1088 "telnet",\r
1089 PROT_TELNET,\r
1090 23\r
1091 };\r