| blob | 4527cb3e038188ca72bcfdc76b5701aee0cb784e |
1 /*\r
2 * Telnet backend.\r
3 */\r
4 \r
5 #include <stdio.h>\r
6 #include <stdlib.h>\r
7 #include <limits.h>\r
8 \r
9 #include "putty.h"\r
10 \r
11 #ifndef FALSE\r
12 #define FALSE 0\r
13 #endif\r
14 #ifndef TRUE\r
15 #define TRUE 1\r
16 #endif\r
17 \r
18 #define IAC 255 /* interpret as command: */\r
19 #define DONT 254 /* you are not to use option */\r
20 #define DO 253 /* please, you use option */\r
21 #define WONT 252 /* I won't use option */\r
22 #define WILL 251 /* I will use option */\r
23 #define SB 250 /* interpret as subnegotiation */\r
24 #define SE 240 /* end sub negotiation */\r
25 \r
26 #define GA 249 /* you may reverse the line */\r
27 #define EL 248 /* erase the current line */\r
28 #define EC 247 /* erase the current character */\r
29 #define AYT 246 /* are you there */\r
30 #define AO 245 /* abort output--but let prog finish */\r
31 #define IP 244 /* interrupt process--permanently */\r
32 #define BREAK 243 /* break */\r
33 #define DM 242 /* data mark--for connect. cleaning */\r
34 #define NOP 241 /* nop */\r
35 #define EOR 239 /* end of record (transparent mode) */\r
36 #define ABORT 238 /* Abort process */\r
37 #define SUSP 237 /* Suspend process */\r
38 #define xEOF 236 /* End of file: EOF is already used... */\r
39 \r
40 #define TELOPTS(X) \\r
41 X(BINARY, 0) /* 8-bit data path */ \\r
42 X(ECHO, 1) /* echo */ \\r
43 X(RCP, 2) /* prepare to reconnect */ \\r
44 X(SGA, 3) /* suppress go ahead */ \\r
45 X(NAMS, 4) /* approximate message size */ \\r
46 X(STATUS, 5) /* give status */ \\r
47 X(TM, 6) /* timing mark */ \\r
48 X(RCTE, 7) /* remote controlled transmission and echo */ \\r
49 X(NAOL, 8) /* negotiate about output line width */ \\r
50 X(NAOP, 9) /* negotiate about output page size */ \\r
51 X(NAOCRD, 10) /* negotiate about CR disposition */ \\r
52 X(NAOHTS, 11) /* negotiate about horizontal tabstops */ \\r
53 X(NAOHTD, 12) /* negotiate about horizontal tab disposition */ \\r
54 X(NAOFFD, 13) /* negotiate about formfeed disposition */ \\r
55 X(NAOVTS, 14) /* negotiate about vertical tab stops */ \\r
56 X(NAOVTD, 15) /* negotiate about vertical tab disposition */ \\r
57 X(NAOLFD, 16) /* negotiate about output LF disposition */ \\r
58 X(XASCII, 17) /* extended ascic character set */ \\r
59 X(LOGOUT, 18) /* force logout */ \\r
60 X(BM, 19) /* byte macro */ \\r
61 X(DET, 20) /* data entry terminal */ \\r
62 X(SUPDUP, 21) /* supdup protocol */ \\r
63 X(SUPDUPOUTPUT, 22) /* supdup output */ \\r
64 X(SNDLOC, 23) /* send location */ \\r
65 X(TTYPE, 24) /* terminal type */ \\r
66 X(EOR, 25) /* end or record */ \\r
67 X(TUID, 26) /* TACACS user identification */ \\r
68 X(OUTMRK, 27) /* output marking */ \\r
69 X(TTYLOC, 28) /* terminal location number */ \\r
70 X(3270REGIME, 29) /* 3270 regime */ \\r
71 X(X3PAD, 30) /* X.3 PAD */ \\r
72 X(NAWS, 31) /* window size */ \\r
73 X(TSPEED, 32) /* terminal speed */ \\r
74 X(LFLOW, 33) /* remote flow control */ \\r
75 X(LINEMODE, 34) /* Linemode option */ \\r
76 X(XDISPLOC, 35) /* X Display Location */ \\r
77 X(OLD_ENVIRON, 36) /* Old - Environment variables */ \\r
78 X(AUTHENTICATION, 37) /* Authenticate */ \\r
79 X(ENCRYPT, 38) /* Encryption option */ \\r
80 X(NEW_ENVIRON, 39) /* New - Environment variables */ \\r
81 X(TN3270E, 40) /* TN3270 enhancements */ \\r
82 X(XAUTH, 41) \\r
83 X(CHARSET, 42) /* Character set */ \\r
84 X(RSP, 43) /* Remote serial port */ \\r
85 X(COM_PORT_OPTION, 44) /* Com port control */ \\r
86 X(SLE, 45) /* Suppress local echo */ \\r
87 X(STARTTLS, 46) /* Start TLS */ \\r
88 X(KERMIT, 47) /* Automatic Kermit file transfer */ \\r
89 X(SEND_URL, 48) \\r
90 X(FORWARD_X, 49) \\r
91 X(PRAGMA_LOGON, 138) \\r
92 X(SSPI_LOGON, 139) \\r
93 X(PRAGMA_HEARTBEAT, 140) \\r
94 X(EXOPL, 255) /* extended-options-list */\r
95 \r
96 #define telnet_enum(x,y) TELOPT_##x = y,\r
97 enum { TELOPTS(telnet_enum) dummy=0 };\r
98 #undef telnet_enum\r
99 \r
100 #define TELQUAL_IS 0 /* option is... */\r
101 #define TELQUAL_SEND 1 /* send option */\r
102 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */\r
103 #define BSD_VAR 1\r
104 #define BSD_VALUE 0\r
105 #define RFC_VAR 0\r
106 #define RFC_VALUE 1\r
107 \r
108 #define CR 13\r
109 #define LF 10\r
110 #define NUL 0\r
111 \r
112 #define iswritable(x) \\r
113 ( (x) != IAC && \\r
114 (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))\r
115 \r
116 static char *telopt(int opt)\r
117 {\r
118 #define telnet_str(x,y) case TELOPT_##x: return #x;\r
119 switch (opt) {\r
120 TELOPTS(telnet_str)\r
121 default:\r
122 return "<unknown>";\r
123 }\r
124 #undef telnet_str\r
125 }\r
126 \r
127 static void telnet_size(void *handle, int width, int height);\r
128 \r
129 struct Opt {\r
130 int send; /* what we initially send */\r
131 int nsend; /* -ve send if requested to stop it */\r
132 int ack, nak; /* +ve and -ve acknowledgements */\r
133 int option; /* the option code */\r
134 int index; /* index into telnet->opt_states[] */\r
135 enum {\r
136 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE\r
137 } initial_state;\r
138 };\r
139 \r
140 enum {\r
141 OPTINDEX_NAWS,\r
142 OPTINDEX_TSPEED,\r
143 OPTINDEX_TTYPE,\r
144 OPTINDEX_OENV,\r
145 OPTINDEX_NENV,\r
146 OPTINDEX_ECHO,\r
147 OPTINDEX_WE_SGA,\r
148 OPTINDEX_THEY_SGA,\r
149 OPTINDEX_WE_BIN,\r
150 OPTINDEX_THEY_BIN,\r
151 NUM_OPTS\r
152 };\r
153 \r
154 static const struct Opt o_naws =\r
155 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };\r
156 static const struct Opt o_tspeed =\r
157 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };\r
158 static const struct Opt o_ttype =\r
159 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };\r
160 static const struct Opt o_oenv =\r
161 { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };\r
162 static const struct Opt o_nenv =\r
163 { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };\r
164 static const struct Opt o_echo =\r
165 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };\r
166 static const struct Opt o_we_sga =\r
167 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };\r
168 static const struct Opt o_they_sga =\r
169 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };\r
170 static const struct Opt o_we_bin =\r
171 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };\r
172 static const struct Opt o_they_bin =\r
173 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };\r
174 \r
175 static const struct Opt *const opts[] = {\r
176 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,\r
177 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL\r
178 };\r
179 \r
180 typedef struct telnet_tag {\r
181 const struct plug_function_table *fn;\r
182 /* the above field _must_ be first in the structure */\r
183 \r
184 Socket s;\r
185 int closed_on_socket_error;\r
186 \r
187 void *frontend;\r
188 void *ldisc;\r
189 int term_width, term_height;\r
190 \r
191 int opt_states[NUM_OPTS];\r
192 \r
193 int echoing, editing;\r
194 int activated;\r
195 int bufsize;\r
196 int in_synch;\r
197 int sb_opt, sb_len;\r
198 unsigned char *sb_buf;\r
199 int sb_size;\r
200 \r
201 enum {\r
202 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,\r
203 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR\r
204 } state;\r
205 \r
206 Conf *conf;\r
207 \r
208 Pinger pinger;\r
209 } *Telnet;\r
210 \r
211 #define TELNET_MAX_BACKLOG 4096\r
212 \r
213 #define SB_DELTA 1024\r
214 \r
215 static void c_write(Telnet telnet, char *buf, int len)\r
216 {\r
217 int backlog;\r
218 backlog = from_backend(telnet->frontend, 0, buf, len);\r
219 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);\r
220 }\r
221 \r
222 static void log_option(Telnet telnet, char *sender, int cmd, int option)\r
223 {\r
224 char *buf;\r
225 /*\r
226 * The strange-looking "<?""?>" below is there to avoid a\r
227 * trigraph - a double question mark followed by > maps to a\r
228 * closing brace character!\r
229 */\r
230 buf = dupprintf("%s:\t%s %s", sender,\r
231 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :\r
232 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),\r
233 telopt(option));\r
234 logevent(telnet->frontend, buf);\r
235 sfree(buf);\r
236 }\r
237 \r
238 static void send_opt(Telnet telnet, int cmd, int option)\r
239 {\r
240 unsigned char b[3];\r
241 \r
242 b[0] = IAC;\r
243 b[1] = cmd;\r
244 b[2] = option;\r
245 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);\r
246 log_option(telnet, "client", cmd, option);\r
247 }\r
248 \r
249 static void deactivate_option(Telnet telnet, const struct Opt *o)\r
250 {\r
251 if (telnet->opt_states[o->index] == REQUESTED ||\r
252 telnet->opt_states[o->index] == ACTIVE)\r
253 send_opt(telnet, o->nsend, o->option);\r
254 telnet->opt_states[o->index] = REALLY_INACTIVE;\r
255 }\r
256 \r
257 /*\r
258 * Generate side effects of enabling or disabling an option.\r
259 */\r
260 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)\r
261 {\r
262 if (o->option == TELOPT_ECHO && o->send == DO)\r
263 telnet->echoing = !enabled;\r
264 else if (o->option == TELOPT_SGA && o->send == DO)\r
265 telnet->editing = !enabled;\r
266 if (telnet->ldisc) /* cause ldisc to notice the change */\r
267 ldisc_send(telnet->ldisc, NULL, 0, 0);\r
268 \r
269 /* Ensure we get the minimum options */\r
270 if (!telnet->activated) {\r
271 if (telnet->opt_states[o_echo.index] == INACTIVE) {\r
272 telnet->opt_states[o_echo.index] = REQUESTED;\r
273 send_opt(telnet, o_echo.send, o_echo.option);\r
274 }\r
275 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {\r
276 telnet->opt_states[o_we_sga.index] = REQUESTED;\r
277 send_opt(telnet, o_we_sga.send, o_we_sga.option);\r
278 }\r
279 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {\r
280 telnet->opt_states[o_they_sga.index] = REQUESTED;\r
281 send_opt(telnet, o_they_sga.send, o_they_sga.option);\r
282 }\r
283 telnet->activated = TRUE;\r
284 }\r
285 }\r
286 \r
287 static void activate_option(Telnet telnet, const struct Opt *o)\r
288 {\r
289 if (o->send == WILL && o->option == TELOPT_NAWS)\r
290 telnet_size(telnet, telnet->term_width, telnet->term_height);\r
291 if (o->send == WILL &&\r
292 (o->option == TELOPT_NEW_ENVIRON ||\r
293 o->option == TELOPT_OLD_ENVIRON)) {\r
294 /*\r
295 * We may only have one kind of ENVIRON going at a time.\r
296 * This is a hack, but who cares.\r
297 */\r
298 deactivate_option(telnet, o->option ==\r
299 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);\r
300 }\r
301 option_side_effects(telnet, o, 1);\r
302 }\r
303 \r
304 static void refused_option(Telnet telnet, const struct Opt *o)\r
305 {\r
306 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&\r
307 telnet->opt_states[o_oenv.index] == INACTIVE) {\r
308 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);\r
309 telnet->opt_states[o_oenv.index] = REQUESTED;\r
310 }\r
311 option_side_effects(telnet, o, 0);\r
312 }\r
313 \r
314 static void proc_rec_opt(Telnet telnet, int cmd, int option)\r
315 {\r
316 const struct Opt *const *o;\r
317 \r
318 log_option(telnet, "server", cmd, option);\r
319 for (o = opts; *o; o++) {\r
320 if ((*o)->option == option && (*o)->ack == cmd) {\r
321 switch (telnet->opt_states[(*o)->index]) {\r
322 case REQUESTED:\r
323 telnet->opt_states[(*o)->index] = ACTIVE;\r
324 activate_option(telnet, *o);\r
325 break;\r
326 case ACTIVE:\r
327 break;\r
328 case INACTIVE:\r
329 telnet->opt_states[(*o)->index] = ACTIVE;\r
330 send_opt(telnet, (*o)->send, option);\r
331 activate_option(telnet, *o);\r
332 break;\r
333 case REALLY_INACTIVE:\r
334 send_opt(telnet, (*o)->nsend, option);\r
335 break;\r
336 }\r
337 return;\r
338 } else if ((*o)->option == option && (*o)->nak == cmd) {\r
339 switch (telnet->opt_states[(*o)->index]) {\r
340 case REQUESTED:\r
341 telnet->opt_states[(*o)->index] = INACTIVE;\r
342 refused_option(telnet, *o);\r
343 break;\r
344 case ACTIVE:\r
345 telnet->opt_states[(*o)->index] = INACTIVE;\r
346 send_opt(telnet, (*o)->nsend, option);\r
347 option_side_effects(telnet, *o, 0);\r
348 break;\r
349 case INACTIVE:\r
350 case REALLY_INACTIVE:\r
351 break;\r
352 }\r
353 return;\r
354 }\r
355 }\r
356 /*\r
357 * If we reach here, the option was one we weren't prepared to\r
358 * cope with. If the request was positive (WILL or DO), we send\r
359 * a negative ack to indicate refusal. If the request was\r
360 * negative (WONT / DONT), we must do nothing.\r
361 */\r
362 if (cmd == WILL || cmd == DO)\r
363 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);\r
364 }\r
365 \r
366 static void process_subneg(Telnet telnet)\r
367 {\r
368 unsigned char *b, *p, *q;\r
369 int var, value, n, bsize;\r
370 char *e, *eval, *ekey, *user;\r
371 \r
372 switch (telnet->sb_opt) {\r
373 case TELOPT_TSPEED:\r
374 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {\r
375 char *logbuf;\r
376 char *termspeed = conf_get_str(telnet->conf, CONF_termspeed);\r
377 b = snewn(20 + strlen(termspeed), unsigned char);\r
378 b[0] = IAC;\r
379 b[1] = SB;\r
380 b[2] = TELOPT_TSPEED;\r
381 b[3] = TELQUAL_IS;\r
382 strcpy((char *)(b + 4), termspeed);\r
383 n = 4 + strlen(termspeed);\r
384 b[n] = IAC;\r
385 b[n + 1] = SE;\r
386 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);\r
387 logevent(telnet->frontend, "server:\tSB TSPEED SEND");\r
388 logbuf = dupprintf("client:\tSB TSPEED IS %s", termspeed);\r
389 logevent(telnet->frontend, logbuf);\r
390 sfree(logbuf);\r
391 sfree(b);\r
392 } else\r
393 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");\r
394 break;\r
395 case TELOPT_TTYPE:\r
396 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {\r
397 char *logbuf;\r
398 char *termtype = conf_get_str(telnet->conf, CONF_termtype);\r
399 b = snewn(20 + strlen(termtype), unsigned char);\r
400 b[0] = IAC;\r
401 b[1] = SB;\r
402 b[2] = TELOPT_TTYPE;\r
403 b[3] = TELQUAL_IS;\r
404 for (n = 0; termtype[n]; n++)\r
405 b[n + 4] = (termtype[n] >= 'a' && termtype[n] <= 'z' ?\r
406 termtype[n] + 'A' - 'a' :\r
407 termtype[n]);\r
408 b[n + 4] = IAC;\r
409 b[n + 5] = SE;\r
410 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);\r
411 b[n + 4] = 0;\r
412 logevent(telnet->frontend, "server:\tSB TTYPE SEND");\r
413 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);\r
414 logevent(telnet->frontend, logbuf);\r
415 sfree(logbuf);\r
416 sfree(b);\r
417 } else\r
418 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");\r
419 break;\r
420 case TELOPT_OLD_ENVIRON:\r
421 case TELOPT_NEW_ENVIRON:\r
422 p = telnet->sb_buf;\r
423 q = p + telnet->sb_len;\r
424 if (p < q && *p == TELQUAL_SEND) {\r
425 char *logbuf;\r
426 p++;\r
427 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));\r
428 logevent(telnet->frontend, logbuf);\r
429 sfree(logbuf);\r
430 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {\r
431 if (conf_get_int(telnet->conf, CONF_rfc_environ)) {\r
432 value = RFC_VALUE;\r
433 var = RFC_VAR;\r
434 } else {\r
435 value = BSD_VALUE;\r
436 var = BSD_VAR;\r
437 }\r
438 /*\r
439 * Try to guess the sense of VAR and VALUE.\r
440 */\r
441 while (p < q) {\r
442 if (*p == RFC_VAR) {\r
443 value = RFC_VALUE;\r
444 var = RFC_VAR;\r
445 } else if (*p == BSD_VAR) {\r
446 value = BSD_VALUE;\r
447 var = BSD_VAR;\r
448 }\r
449 p++;\r
450 }\r
451 } else {\r
452 /*\r
453 * With NEW_ENVIRON, the sense of VAR and VALUE\r
454 * isn't in doubt.\r
455 */\r
456 value = RFC_VALUE;\r
457 var = RFC_VAR;\r
458 }\r
459 bsize = 20;\r
460 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
461 NULL, &ekey);\r
462 eval != NULL;\r
463 eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
464 ekey, &ekey))\r
465 bsize += strlen(ekey) + strlen(eval) + 2;\r
466 user = get_remote_username(telnet->conf);\r
467 if (user)\r
468 bsize += 6 + strlen(user);\r
469 \r
470 b = snewn(bsize, unsigned char);\r
471 b[0] = IAC;\r
472 b[1] = SB;\r
473 b[2] = telnet->sb_opt;\r
474 b[3] = TELQUAL_IS;\r
475 n = 4;\r
476 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
477 NULL, &ekey);\r
478 eval != NULL;\r
479 eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
480 ekey, &ekey)) {\r
481 b[n++] = var;\r
482 for (e = ekey; *e; e++)\r
483 b[n++] = *e;\r
484 b[n++] = value;\r
485 for (e = eval; *e; e++)\r
486 b[n++] = *e;\r
487 }\r
488 if (user) {\r
489 b[n++] = var;\r
490 b[n++] = 'U';\r
491 b[n++] = 'S';\r
492 b[n++] = 'E';\r
493 b[n++] = 'R';\r
494 b[n++] = value;\r
495 for (e = user; *e; e++)\r
496 b[n++] = *e;\r
497 }\r
498 b[n++] = IAC;\r
499 b[n++] = SE;\r
500 telnet->bufsize = sk_write(telnet->s, (char *)b, n);\r
501 if (n == 6) {\r
502 logbuf = dupprintf("client:\tSB %s IS <nothing>",\r
503 telopt(telnet->sb_opt));\r
504 logevent(telnet->frontend, logbuf);\r
505 sfree(logbuf);\r
506 } else {\r
507 logbuf = dupprintf("client:\tSB %s IS:",\r
508 telopt(telnet->sb_opt));\r
509 logevent(telnet->frontend, logbuf);\r
510 sfree(logbuf);\r
511 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
512 NULL, &ekey);\r
513 eval != NULL;\r
514 eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
515 ekey, &ekey)) {\r
516 logbuf = dupprintf("\t%s=%s", ekey, eval);\r
517 logevent(telnet->frontend, logbuf);\r
518 sfree(logbuf);\r
519 }\r
520 if (user) {\r
521 logbuf = dupprintf("\tUSER=%s", user);\r
522 logevent(telnet->frontend, logbuf);\r
523 sfree(logbuf);\r
524 }\r
525 }\r
526 sfree(b);\r
527 sfree(user);\r
528 }\r
529 break;\r
530 }\r
531 }\r
532 \r
533 static void do_telnet_read(Telnet telnet, char *buf, int len)\r
534 {\r
535 char *outbuf = NULL;\r
536 int outbuflen = 0, outbufsize = 0;\r
537 \r
538 #define ADDTOBUF(c) do { \\r
539 if (outbuflen >= outbufsize) { \\r
540 outbufsize = outbuflen + 256; \\r
541 outbuf = sresize(outbuf, outbufsize, char); \\r
542 } \\r
543 outbuf[outbuflen++] = (c); \\r
544 } while (0)\r
545 \r
546 while (len--) {\r
547 int c = (unsigned char) *buf++;\r
548 \r
549 switch (telnet->state) {\r
550 case TOP_LEVEL:\r
551 case SEENCR:\r
552 if (c == NUL && telnet->state == SEENCR)\r
553 telnet->state = TOP_LEVEL;\r
554 else if (c == IAC)\r
555 telnet->state = SEENIAC;\r
556 else {\r
557 if (!telnet->in_synch)\r
558 ADDTOBUF(c);\r
559 \r
560 #if 1\r
561 /* I can't get the F***ing winsock to insert the urgent IAC\r
562 * into the right position! Even with SO_OOBINLINE it gives\r
563 * it to recv too soon. And of course the DM byte (that\r
564 * arrives in the same packet!) appears several K later!!\r
565 *\r
566 * Oh well, we do get the DM in the right place so I'll\r
567 * just stop hiding on the next 0xf2 and hope for the best.\r
568 */\r
569 else if (c == DM)\r
570 telnet->in_synch = 0;\r
571 #endif\r
572 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)\r
573 telnet->state = SEENCR;\r
574 else\r
575 telnet->state = TOP_LEVEL;\r
576 }\r
577 break;\r
578 case SEENIAC:\r
579 if (c == DO)\r
580 telnet->state = SEENDO;\r
581 else if (c == DONT)\r
582 telnet->state = SEENDONT;\r
583 else if (c == WILL)\r
584 telnet->state = SEENWILL;\r
585 else if (c == WONT)\r
586 telnet->state = SEENWONT;\r
587 else if (c == SB)\r
588 telnet->state = SEENSB;\r
589 else if (c == DM) {\r
590 telnet->in_synch = 0;\r
591 telnet->state = TOP_LEVEL;\r
592 } else {\r
593 /* ignore everything else; print it if it's IAC */\r
594 if (c == IAC) {\r
595 ADDTOBUF(c);\r
596 }\r
597 telnet->state = TOP_LEVEL;\r
598 }\r
599 break;\r
600 case SEENWILL:\r
601 proc_rec_opt(telnet, WILL, c);\r
602 telnet->state = TOP_LEVEL;\r
603 break;\r
604 case SEENWONT:\r
605 proc_rec_opt(telnet, WONT, c);\r
606 telnet->state = TOP_LEVEL;\r
607 break;\r
608 case SEENDO:\r
609 proc_rec_opt(telnet, DO, c);\r
610 telnet->state = TOP_LEVEL;\r
611 break;\r
612 case SEENDONT:\r
613 proc_rec_opt(telnet, DONT, c);\r
614 telnet->state = TOP_LEVEL;\r
615 break;\r
616 case SEENSB:\r
617 telnet->sb_opt = c;\r
618 telnet->sb_len = 0;\r
619 telnet->state = SUBNEGOT;\r
620 break;\r
621 case SUBNEGOT:\r
622 if (c == IAC)\r
623 telnet->state = SUBNEG_IAC;\r
624 else {\r
625 subneg_addchar:\r
626 if (telnet->sb_len >= telnet->sb_size) {\r
627 telnet->sb_size += SB_DELTA;\r
628 telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,\r
629 unsigned char);\r
630 }\r
631 telnet->sb_buf[telnet->sb_len++] = c;\r
632 telnet->state = SUBNEGOT; /* in case we came here by goto */\r
633 }\r
634 break;\r
635 case SUBNEG_IAC:\r
636 if (c != SE)\r
637 goto subneg_addchar; /* yes, it's a hack, I know, but... */\r
638 else {\r
639 process_subneg(telnet);\r
640 telnet->state = TOP_LEVEL;\r
641 }\r
642 break;\r
643 }\r
644 }\r
645 \r
646 if (outbuflen)\r
647 c_write(telnet, outbuf, outbuflen);\r
648 sfree(outbuf);\r
649 }\r
650 \r
651 static void telnet_log(Plug plug, int type, SockAddr addr, int port,\r
652 const char *error_msg, int error_code)\r
653 {\r
654 Telnet telnet = (Telnet) plug;\r
655 char addrbuf[256], *msg;\r
656 \r
657 sk_getaddr(addr, addrbuf, lenof(addrbuf));\r
658 \r
659 if (type == 0)\r
660 msg = dupprintf("Connecting to %s port %d", addrbuf, port);\r
661 else\r
662 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);\r
663 \r
664 logevent(telnet->frontend, msg);\r
665 sfree(msg);\r
666 }\r
667 \r
668 static int telnet_closing(Plug plug, const char *error_msg, int error_code,\r
669 int calling_back)\r
670 {\r
671 Telnet telnet = (Telnet) plug;\r
672 \r
673 /*\r
674 * We don't implement independent EOF in each direction for Telnet\r
675 * connections; as soon as we get word that the remote side has\r
676 * sent us EOF, we wind up the whole connection.\r
677 */\r
678 \r
679 if (telnet->s) {\r
680 sk_close(telnet->s);\r
681 telnet->s = NULL;\r
682 if (error_msg)\r
683 telnet->closed_on_socket_error = TRUE;\r
684 notify_remote_exit(telnet->frontend);\r
685 }\r
686 if (error_msg) {\r
687 logevent(telnet->frontend, error_msg);\r
688 connection_fatal(telnet->frontend, "%s", error_msg);\r
689 }\r
690 /* Otherwise, the remote side closed the connection normally. */\r
691 return 0;\r
692 }\r
693 \r
694 static int telnet_receive(Plug plug, int urgent, char *data, int len)\r
695 {\r
696 Telnet telnet = (Telnet) plug;\r
697 if (urgent)\r
698 telnet->in_synch = TRUE;\r
699 do_telnet_read(telnet, data, len);\r
700 return 1;\r
701 }\r
702 \r
703 static void telnet_sent(Plug plug, int bufsize)\r
704 {\r
705 Telnet telnet = (Telnet) plug;\r
706 telnet->bufsize = bufsize;\r
707 }\r
708 \r
709 /*\r
710 * Called to set up the Telnet connection.\r
711 *\r
712 * Returns an error message, or NULL on success.\r
713 *\r
714 * Also places the canonical host name into `realhost'. It must be\r
715 * freed by the caller.\r
716 */\r
717 static const char *telnet_init(void *frontend_handle, void **backend_handle,\r
718 Conf *conf, char *host, int port,\r
719 char **realhost, int nodelay, int keepalive)\r
720 {\r
721 static const struct plug_function_table fn_table = {\r
722 telnet_log,\r
723 telnet_closing,\r
724 telnet_receive,\r
725 telnet_sent\r
726 };\r
727 SockAddr addr;\r
728 const char *err;\r
729 Telnet telnet;\r
730 char *loghost;\r
731 int addressfamily;\r
732 \r
733 telnet = snew(struct telnet_tag);\r
734 telnet->fn = &fn_table;\r
735 telnet->conf = conf_copy(conf);\r
736 telnet->s = NULL;\r
737 telnet->closed_on_socket_error = FALSE;\r
738 telnet->echoing = TRUE;\r
739 telnet->editing = TRUE;\r
740 telnet->activated = FALSE;\r
741 telnet->sb_buf = NULL;\r
742 telnet->sb_size = 0;\r
743 telnet->frontend = frontend_handle;\r
744 telnet->term_width = conf_get_int(telnet->conf, CONF_width);\r
745 telnet->term_height = conf_get_int(telnet->conf, CONF_height);\r
746 telnet->state = TOP_LEVEL;\r
747 telnet->ldisc = NULL;\r
748 telnet->pinger = NULL;\r
749 *backend_handle = telnet;\r
750 \r
751 /*\r
752 * Try to find host.\r
753 */\r
754 {\r
755 char *buf;\r
756 addressfamily = conf_get_int(telnet->conf, CONF_addressfamily);\r
757 buf = dupprintf("Looking up host \"%s\"%s", host,\r
758 (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :\r
759 (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :\r
760 "")));\r
761 logevent(telnet->frontend, buf);\r
762 sfree(buf);\r
763 }\r
764 addr = name_lookup(host, port, realhost, telnet->conf, addressfamily);\r
765 if ((err = sk_addr_error(addr)) != NULL) {\r
766 sk_addr_free(addr);\r
767 return err;\r
768 }\r
769 \r
770 if (port < 0)\r
771 port = 23; /* default telnet port */\r
772 \r
773 /*\r
774 * Open socket.\r
775 */\r
776 telnet->s = new_connection(addr, *realhost, port, 0, 1,\r
777 nodelay, keepalive, (Plug) telnet, telnet->conf);\r
778 if ((err = sk_socket_error(telnet->s)) != NULL)\r
779 return err;\r
780 \r
781 telnet->pinger = pinger_new(telnet->conf, &telnet_backend, telnet);\r
782 \r
783 /*\r
784 * Initialise option states.\r
785 */\r
786 if (conf_get_int(telnet->conf, CONF_passive_telnet)) {\r
787 const struct Opt *const *o;\r
788 \r
789 for (o = opts; *o; o++)\r
790 telnet->opt_states[(*o)->index] = INACTIVE;\r
791 } else {\r
792 const struct Opt *const *o;\r
793 \r
794 for (o = opts; *o; o++) {\r
795 telnet->opt_states[(*o)->index] = (*o)->initial_state;\r
796 if (telnet->opt_states[(*o)->index] == REQUESTED)\r
797 send_opt(telnet, (*o)->send, (*o)->option);\r
798 }\r
799 telnet->activated = TRUE;\r
800 }\r
801 \r
802 /*\r
803 * Set up SYNCH state.\r
804 */\r
805 telnet->in_synch = FALSE;\r
806 \r
807 /*\r
808 * We can send special commands from the start.\r
809 */\r
810 update_specials_menu(telnet->frontend);\r
811 \r
812 /*\r
813 * loghost overrides realhost, if specified.\r
814 */\r
815 loghost = conf_get_str(telnet->conf, CONF_loghost);\r
816 if (*loghost) {\r
817 char *colon;\r
818 \r
819 sfree(*realhost);\r
820 *realhost = dupstr(loghost);\r
821 \r
822 colon = host_strrchr(*realhost, ':');\r
823 if (colon)\r
824 *colon++ = '\0';\r
825 }\r
826 \r
827 return NULL;\r
828 }\r
829 \r
830 static void telnet_free(void *handle)\r
831 {\r
832 Telnet telnet = (Telnet) handle;\r
833 \r
834 sfree(telnet->sb_buf);\r
835 if (telnet->s)\r
836 sk_close(telnet->s);\r
837 if (telnet->pinger)\r
838 pinger_free(telnet->pinger);\r
839 conf_free(telnet->conf);\r
840 sfree(telnet);\r
841 }\r
842 /*\r
843 * Reconfigure the Telnet backend. There's no immediate action\r
844 * necessary, in this backend: we just save the fresh config for\r
845 * any subsequent negotiations.\r
846 */\r
847 static void telnet_reconfig(void *handle, Conf *conf)\r
848 {\r
849 Telnet telnet = (Telnet) handle;\r
850 pinger_reconfig(telnet->pinger, telnet->conf, conf);\r
851 conf_free(telnet->conf);\r
852 telnet->conf = conf_copy(conf);\r
853 }\r
854 \r
855 /*\r
856 * Called to send data down the Telnet connection.\r
857 */\r
858 static int telnet_send(void *handle, char *buf, int len)\r
859 {\r
860 Telnet telnet = (Telnet) handle;\r
861 unsigned char *p, *end;\r
862 static const unsigned char iac[2] = { IAC, IAC };\r
863 static const unsigned char cr[2] = { CR, NUL };\r
864 #if 0\r
865 static const unsigned char nl[2] = { CR, LF };\r
866 #endif\r
867 \r
868 if (telnet->s == NULL)\r
869 return 0;\r
870 \r
871 p = (unsigned char *)buf;\r
872 end = (unsigned char *)(buf + len);\r
873 while (p < end) {\r
874 unsigned char *q = p;\r
875 \r
876 while (p < end && iswritable(*p))\r
877 p++;\r
878 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);\r
879 \r
880 while (p < end && !iswritable(*p)) {\r
881 telnet->bufsize = \r
882 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);\r
883 p++;\r
884 }\r
885 }\r
886 \r
887 return telnet->bufsize;\r
888 }\r
889 \r
890 /*\r
891 * Called to query the current socket sendability status.\r
892 */\r
893 static int telnet_sendbuffer(void *handle)\r
894 {\r
895 Telnet telnet = (Telnet) handle;\r
896 return telnet->bufsize;\r
897 }\r
898 \r
899 /*\r
900 * Called to set the size of the window from Telnet's POV.\r
901 */\r
902 static void telnet_size(void *handle, int width, int height)\r
903 {\r
904 Telnet telnet = (Telnet) handle;\r
905 unsigned char b[24];\r
906 int n;\r
907 char *logbuf;\r
908 \r
909 telnet->term_width = width;\r
910 telnet->term_height = height;\r
911 \r
912 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)\r
913 return;\r
914 n = 0;\r
915 b[n++] = IAC;\r
916 b[n++] = SB;\r
917 b[n++] = TELOPT_NAWS;\r
918 b[n++] = telnet->term_width >> 8;\r
919 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
920 b[n++] = telnet->term_width & 0xFF;\r
921 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
922 b[n++] = telnet->term_height >> 8;\r
923 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
924 b[n++] = telnet->term_height & 0xFF;\r
925 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
926 b[n++] = IAC;\r
927 b[n++] = SE;\r
928 telnet->bufsize = sk_write(telnet->s, (char *)b, n);\r
929 logbuf = dupprintf("client:\tSB NAWS %d,%d",\r
930 telnet->term_width, telnet->term_height);\r
931 logevent(telnet->frontend, logbuf);\r
932 sfree(logbuf);\r
933 }\r
934 \r
935 /*\r
936 * Send Telnet special codes.\r
937 */\r
938 static void telnet_special(void *handle, Telnet_Special code)\r
939 {\r
940 Telnet telnet = (Telnet) handle;\r
941 unsigned char b[2];\r
942 \r
943 if (telnet->s == NULL)\r
944 return;\r
945 \r
946 b[0] = IAC;\r
947 switch (code) {\r
948 case TS_AYT:\r
949 b[1] = AYT;\r
950 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
951 break;\r
952 case TS_BRK:\r
953 b[1] = BREAK;\r
954 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
955 break;\r
956 case TS_EC:\r
957 b[1] = EC;\r
958 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
959 break;\r
960 case TS_EL:\r
961 b[1] = EL;\r
962 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
963 break;\r
964 case TS_GA:\r
965 b[1] = GA;\r
966 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
967 break;\r
968 case TS_NOP:\r
969 b[1] = NOP;\r
970 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
971 break;\r
972 case TS_ABORT:\r
973 b[1] = ABORT;\r
974 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
975 break;\r
976 case TS_AO:\r
977 b[1] = AO;\r
978 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
979 break;\r
980 case TS_IP:\r
981 b[1] = IP;\r
982 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
983 break;\r
984 case TS_SUSP:\r
985 b[1] = SUSP;\r
986 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
987 break;\r
988 case TS_EOR:\r
989 b[1] = EOR;\r
990 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
991 break;\r
992 case TS_EOF:\r
993 b[1] = xEOF;\r
994 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
995 break;\r
996 case TS_EOL:\r
997 /* In BINARY mode, CR-LF becomes just CR -\r
998 * and without the NUL suffix too. */\r
999 if (telnet->opt_states[o_we_bin.index] == ACTIVE)\r
1000 telnet->bufsize = sk_write(telnet->s, "\r", 1);\r
1001 else\r
1002 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);\r
1003 break;\r
1004 case TS_SYNCH:\r
1005 b[1] = DM;\r
1006 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);\r
1007 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);\r
1008 break;\r
1009 case TS_RECHO:\r
1010 if (telnet->opt_states[o_echo.index] == INACTIVE ||\r
1011 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {\r
1012 telnet->opt_states[o_echo.index] = REQUESTED;\r
1013 send_opt(telnet, o_echo.send, o_echo.option);\r
1014 }\r
1015 break;\r
1016 case TS_LECHO:\r
1017 if (telnet->opt_states[o_echo.index] == ACTIVE) {\r
1018 telnet->opt_states[o_echo.index] = REQUESTED;\r
1019 send_opt(telnet, o_echo.nsend, o_echo.option);\r
1020 }\r
1021 break;\r
1022 case TS_PING:\r
1023 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {\r
1024 b[1] = NOP;\r
1025 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
1026 }\r
1027 break;\r
1028 default:\r
1029 break; /* never heard of it */\r
1030 }\r
1031 }\r
1032 \r
1033 static const struct telnet_special *telnet_get_specials(void *handle)\r
1034 {\r
1035 static const struct telnet_special specials[] = {\r
1036 {"Are You There", TS_AYT},\r
1037 {"Break", TS_BRK},\r
1038 {"Synch", TS_SYNCH},\r
1039 {"Erase Character", TS_EC},\r
1040 {"Erase Line", TS_EL},\r
1041 {"Go Ahead", TS_GA},\r
1042 {"No Operation", TS_NOP},\r
1043 {NULL, TS_SEP},\r
1044 {"Abort Process", TS_ABORT},\r
1045 {"Abort Output", TS_AO},\r
1046 {"Interrupt Process", TS_IP},\r
1047 {"Suspend Process", TS_SUSP},\r
1048 {NULL, TS_SEP},\r
1049 {"End Of Record", TS_EOR},\r
1050 {"End Of File", TS_EOF},\r
1051 {NULL, TS_EXITMENU}\r
1052 };\r
1053 return specials;\r
1054 }\r
1055 \r
1056 static int telnet_connected(void *handle)\r
1057 {\r
1058 Telnet telnet = (Telnet) handle;\r
1059 return telnet->s != NULL;\r
1060 }\r
1061 \r
1062 static int telnet_sendok(void *handle)\r
1063 {\r
1064 /* Telnet telnet = (Telnet) handle; */\r
1065 return 1;\r
1066 }\r
1067 \r
1068 static void telnet_unthrottle(void *handle, int backlog)\r
1069 {\r
1070 Telnet telnet = (Telnet) handle;\r
1071 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);\r
1072 }\r
1073 \r
1074 static int telnet_ldisc(void *handle, int option)\r
1075 {\r
1076 Telnet telnet = (Telnet) handle;\r
1077 if (option == LD_ECHO)\r
1078 return telnet->echoing;\r
1079 if (option == LD_EDIT)\r
1080 return telnet->editing;\r
1081 return FALSE;\r
1082 }\r
1083 \r
1084 static void telnet_provide_ldisc(void *handle, void *ldisc)\r
1085 {\r
1086 Telnet telnet = (Telnet) handle;\r
1087 telnet->ldisc = ldisc;\r
1088 }\r
1089 \r
1090 static void telnet_provide_logctx(void *handle, void *logctx)\r
1091 {\r
1092 /* This is a stub. */\r
1093 }\r
1094 \r
1095 static int telnet_exitcode(void *handle)\r
1096 {\r
1097 Telnet telnet = (Telnet) handle;\r
1098 if (telnet->s != NULL)\r
1099 return -1; /* still connected */\r
1100 else if (telnet->closed_on_socket_error)\r
1101 return INT_MAX; /* a socket error counts as an unclean exit */\r
1102 else\r
1103 /* Telnet doesn't transmit exit codes back to the client */\r
1104 return 0;\r
1105 }\r
1106 \r
1107 /*\r
1108 * cfg_info for Telnet does nothing at all.\r
1109 */\r
1110 static int telnet_cfg_info(void *handle)\r
1111 {\r
1112 return 0;\r
1113 }\r
1114 \r
1115 Backend telnet_backend = {\r
1116 telnet_init,\r
1117 telnet_free,\r
1118 telnet_reconfig,\r
1119 telnet_send,\r
1120 telnet_sendbuffer,\r
1121 telnet_size,\r
1122 telnet_special,\r
1123 telnet_get_specials,\r
1124 telnet_connected,\r
1125 telnet_exitcode,\r
1126 telnet_sendok,\r
1127 telnet_ldisc,\r
1128 telnet_provide_ldisc,\r
1129 telnet_provide_logctx,\r
1130 telnet_unthrottle,\r
1131 telnet_cfg_info,\r
1132 "telnet",\r
1133 PROT_TELNET,\r
1134 23\r
1135 };\r