| blob | 1589d6c6cfca4f0bd165fbb804b46bf608a7d8fc |
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 const 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 int session_started;\r
201 \r
202 enum {\r
203 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,\r
204 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR\r
205 } state;\r
206 \r
207 Conf *conf;\r
208 \r
209 Pinger pinger;\r
210 } *Telnet;\r
211 \r
212 #define TELNET_MAX_BACKLOG 4096\r
213 \r
214 #define SB_DELTA 1024\r
215 \r
216 static void c_write(Telnet telnet, const char *buf, int len)\r
217 {\r
218 int backlog;\r
219 backlog = from_backend(telnet->frontend, 0, buf, len);\r
220 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);\r
221 }\r
222 \r
223 static void log_option(Telnet telnet, const char *sender, int cmd, int option)\r
224 {\r
225 char *buf;\r
226 /*\r
227 * The strange-looking "<?""?>" below is there to avoid a\r
228 * trigraph - a double question mark followed by > maps to a\r
229 * closing brace character!\r
230 */\r
231 buf = dupprintf("%s:\t%s %s", sender,\r
232 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :\r
233 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),\r
234 telopt(option));\r
235 logevent(telnet->frontend, buf);\r
236 sfree(buf);\r
237 }\r
238 \r
239 static void send_opt(Telnet telnet, int cmd, int option)\r
240 {\r
241 unsigned char b[3];\r
242 \r
243 b[0] = IAC;\r
244 b[1] = cmd;\r
245 b[2] = option;\r
246 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);\r
247 log_option(telnet, "client", cmd, option);\r
248 }\r
249 \r
250 static void deactivate_option(Telnet telnet, const struct Opt *o)\r
251 {\r
252 if (telnet->opt_states[o->index] == REQUESTED ||\r
253 telnet->opt_states[o->index] == ACTIVE)\r
254 send_opt(telnet, o->nsend, o->option);\r
255 telnet->opt_states[o->index] = REALLY_INACTIVE;\r
256 }\r
257 \r
258 /*\r
259 * Generate side effects of enabling or disabling an option.\r
260 */\r
261 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)\r
262 {\r
263 if (o->option == TELOPT_ECHO && o->send == DO)\r
264 telnet->echoing = !enabled;\r
265 else if (o->option == TELOPT_SGA && o->send == DO)\r
266 telnet->editing = !enabled;\r
267 if (telnet->ldisc) /* cause ldisc to notice the change */\r
268 ldisc_echoedit_update(telnet->ldisc);\r
269 \r
270 /* Ensure we get the minimum options */\r
271 if (!telnet->activated) {\r
272 if (telnet->opt_states[o_echo.index] == INACTIVE) {\r
273 telnet->opt_states[o_echo.index] = REQUESTED;\r
274 send_opt(telnet, o_echo.send, o_echo.option);\r
275 }\r
276 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {\r
277 telnet->opt_states[o_we_sga.index] = REQUESTED;\r
278 send_opt(telnet, o_we_sga.send, o_we_sga.option);\r
279 }\r
280 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {\r
281 telnet->opt_states[o_they_sga.index] = REQUESTED;\r
282 send_opt(telnet, o_they_sga.send, o_they_sga.option);\r
283 }\r
284 telnet->activated = TRUE;\r
285 }\r
286 }\r
287 \r
288 static void activate_option(Telnet telnet, const struct Opt *o)\r
289 {\r
290 if (o->send == WILL && o->option == TELOPT_NAWS)\r
291 telnet_size(telnet, telnet->term_width, telnet->term_height);\r
292 if (o->send == WILL &&\r
293 (o->option == TELOPT_NEW_ENVIRON ||\r
294 o->option == TELOPT_OLD_ENVIRON)) {\r
295 /*\r
296 * We may only have one kind of ENVIRON going at a time.\r
297 * This is a hack, but who cares.\r
298 */\r
299 deactivate_option(telnet, o->option ==\r
300 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);\r
301 }\r
302 option_side_effects(telnet, o, 1);\r
303 }\r
304 \r
305 static void refused_option(Telnet telnet, const struct Opt *o)\r
306 {\r
307 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&\r
308 telnet->opt_states[o_oenv.index] == INACTIVE) {\r
309 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);\r
310 telnet->opt_states[o_oenv.index] = REQUESTED;\r
311 }\r
312 option_side_effects(telnet, o, 0);\r
313 }\r
314 \r
315 static void proc_rec_opt(Telnet telnet, int cmd, int option)\r
316 {\r
317 const struct Opt *const *o;\r
318 \r
319 log_option(telnet, "server", cmd, option);\r
320 for (o = opts; *o; o++) {\r
321 if ((*o)->option == option && (*o)->ack == cmd) {\r
322 switch (telnet->opt_states[(*o)->index]) {\r
323 case REQUESTED:\r
324 telnet->opt_states[(*o)->index] = ACTIVE;\r
325 activate_option(telnet, *o);\r
326 break;\r
327 case ACTIVE:\r
328 break;\r
329 case INACTIVE:\r
330 telnet->opt_states[(*o)->index] = ACTIVE;\r
331 send_opt(telnet, (*o)->send, option);\r
332 activate_option(telnet, *o);\r
333 break;\r
334 case REALLY_INACTIVE:\r
335 send_opt(telnet, (*o)->nsend, option);\r
336 break;\r
337 }\r
338 return;\r
339 } else if ((*o)->option == option && (*o)->nak == cmd) {\r
340 switch (telnet->opt_states[(*o)->index]) {\r
341 case REQUESTED:\r
342 telnet->opt_states[(*o)->index] = INACTIVE;\r
343 refused_option(telnet, *o);\r
344 break;\r
345 case ACTIVE:\r
346 telnet->opt_states[(*o)->index] = INACTIVE;\r
347 send_opt(telnet, (*o)->nsend, option);\r
348 option_side_effects(telnet, *o, 0);\r
349 break;\r
350 case INACTIVE:\r
351 case REALLY_INACTIVE:\r
352 break;\r
353 }\r
354 return;\r
355 }\r
356 }\r
357 /*\r
358 * If we reach here, the option was one we weren't prepared to\r
359 * cope with. If the request was positive (WILL or DO), we send\r
360 * a negative ack to indicate refusal. If the request was\r
361 * negative (WONT / DONT), we must do nothing.\r
362 */\r
363 if (cmd == WILL || cmd == DO)\r
364 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);\r
365 }\r
366 \r
367 static void process_subneg(Telnet telnet)\r
368 {\r
369 unsigned char *b, *p, *q;\r
370 int var, value, n, bsize;\r
371 char *e, *eval, *ekey, *user;\r
372 \r
373 switch (telnet->sb_opt) {\r
374 case TELOPT_TSPEED:\r
375 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {\r
376 char *logbuf;\r
377 char *termspeed = conf_get_str(telnet->conf, CONF_termspeed);\r
378 b = snewn(20 + strlen(termspeed), unsigned char);\r
379 b[0] = IAC;\r
380 b[1] = SB;\r
381 b[2] = TELOPT_TSPEED;\r
382 b[3] = TELQUAL_IS;\r
383 strcpy((char *)(b + 4), termspeed);\r
384 n = 4 + strlen(termspeed);\r
385 b[n] = IAC;\r
386 b[n + 1] = SE;\r
387 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);\r
388 logevent(telnet->frontend, "server:\tSB TSPEED SEND");\r
389 logbuf = dupprintf("client:\tSB TSPEED IS %s", termspeed);\r
390 logevent(telnet->frontend, logbuf);\r
391 sfree(logbuf);\r
392 sfree(b);\r
393 } else\r
394 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");\r
395 break;\r
396 case TELOPT_TTYPE:\r
397 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {\r
398 char *logbuf;\r
399 char *termtype = conf_get_str(telnet->conf, CONF_termtype);\r
400 b = snewn(20 + strlen(termtype), unsigned char);\r
401 b[0] = IAC;\r
402 b[1] = SB;\r
403 b[2] = TELOPT_TTYPE;\r
404 b[3] = TELQUAL_IS;\r
405 for (n = 0; termtype[n]; n++)\r
406 b[n + 4] = (termtype[n] >= 'a' && termtype[n] <= 'z' ?\r
407 termtype[n] + 'A' - 'a' :\r
408 termtype[n]);\r
409 b[n + 4] = IAC;\r
410 b[n + 5] = SE;\r
411 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);\r
412 b[n + 4] = 0;\r
413 logevent(telnet->frontend, "server:\tSB TTYPE SEND");\r
414 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);\r
415 logevent(telnet->frontend, logbuf);\r
416 sfree(logbuf);\r
417 sfree(b);\r
418 } else\r
419 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");\r
420 break;\r
421 case TELOPT_OLD_ENVIRON:\r
422 case TELOPT_NEW_ENVIRON:\r
423 p = telnet->sb_buf;\r
424 q = p + telnet->sb_len;\r
425 if (p < q && *p == TELQUAL_SEND) {\r
426 char *logbuf;\r
427 p++;\r
428 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));\r
429 logevent(telnet->frontend, logbuf);\r
430 sfree(logbuf);\r
431 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {\r
432 if (conf_get_int(telnet->conf, CONF_rfc_environ)) {\r
433 value = RFC_VALUE;\r
434 var = RFC_VAR;\r
435 } else {\r
436 value = BSD_VALUE;\r
437 var = BSD_VAR;\r
438 }\r
439 /*\r
440 * Try to guess the sense of VAR and VALUE.\r
441 */\r
442 while (p < q) {\r
443 if (*p == RFC_VAR) {\r
444 value = RFC_VALUE;\r
445 var = RFC_VAR;\r
446 } else if (*p == BSD_VAR) {\r
447 value = BSD_VALUE;\r
448 var = BSD_VAR;\r
449 }\r
450 p++;\r
451 }\r
452 } else {\r
453 /*\r
454 * With NEW_ENVIRON, the sense of VAR and VALUE\r
455 * isn't in doubt.\r
456 */\r
457 value = RFC_VALUE;\r
458 var = RFC_VAR;\r
459 }\r
460 bsize = 20;\r
461 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
462 NULL, &ekey);\r
463 eval != NULL;\r
464 eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
465 ekey, &ekey))\r
466 bsize += strlen(ekey) + strlen(eval) + 2;\r
467 user = get_remote_username(telnet->conf);\r
468 if (user)\r
469 bsize += 6 + strlen(user);\r
470 \r
471 b = snewn(bsize, unsigned char);\r
472 b[0] = IAC;\r
473 b[1] = SB;\r
474 b[2] = telnet->sb_opt;\r
475 b[3] = TELQUAL_IS;\r
476 n = 4;\r
477 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
478 NULL, &ekey);\r
479 eval != NULL;\r
480 eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
481 ekey, &ekey)) {\r
482 b[n++] = var;\r
483 for (e = ekey; *e; e++)\r
484 b[n++] = *e;\r
485 b[n++] = value;\r
486 for (e = eval; *e; e++)\r
487 b[n++] = *e;\r
488 }\r
489 if (user) {\r
490 b[n++] = var;\r
491 b[n++] = 'U';\r
492 b[n++] = 'S';\r
493 b[n++] = 'E';\r
494 b[n++] = 'R';\r
495 b[n++] = value;\r
496 for (e = user; *e; e++)\r
497 b[n++] = *e;\r
498 }\r
499 b[n++] = IAC;\r
500 b[n++] = SE;\r
501 telnet->bufsize = sk_write(telnet->s, (char *)b, n);\r
502 if (n == 6) {\r
503 logbuf = dupprintf("client:\tSB %s IS <nothing>",\r
504 telopt(telnet->sb_opt));\r
505 logevent(telnet->frontend, logbuf);\r
506 sfree(logbuf);\r
507 } else {\r
508 logbuf = dupprintf("client:\tSB %s IS:",\r
509 telopt(telnet->sb_opt));\r
510 logevent(telnet->frontend, logbuf);\r
511 sfree(logbuf);\r
512 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
513 NULL, &ekey);\r
514 eval != NULL;\r
515 eval = conf_get_str_strs(telnet->conf, CONF_environmt,\r
516 ekey, &ekey)) {\r
517 logbuf = dupprintf("\t%s=%s", ekey, eval);\r
518 logevent(telnet->frontend, logbuf);\r
519 sfree(logbuf);\r
520 }\r
521 if (user) {\r
522 logbuf = dupprintf("\tUSER=%s", user);\r
523 logevent(telnet->frontend, logbuf);\r
524 sfree(logbuf);\r
525 }\r
526 }\r
527 sfree(b);\r
528 sfree(user);\r
529 }\r
530 break;\r
531 }\r
532 }\r
533 \r
534 static void do_telnet_read(Telnet telnet, char *buf, int len)\r
535 {\r
536 char *outbuf = NULL;\r
537 int outbuflen = 0, outbufsize = 0;\r
538 \r
539 #define ADDTOBUF(c) do { \\r
540 if (outbuflen >= outbufsize) { \\r
541 outbufsize = outbuflen + 256; \\r
542 outbuf = sresize(outbuf, outbufsize, char); \\r
543 } \\r
544 outbuf[outbuflen++] = (c); \\r
545 } while (0)\r
546 \r
547 while (len--) {\r
548 int c = (unsigned char) *buf++;\r
549 \r
550 switch (telnet->state) {\r
551 case TOP_LEVEL:\r
552 case SEENCR:\r
553 if (c == NUL && telnet->state == SEENCR)\r
554 telnet->state = TOP_LEVEL;\r
555 else if (c == IAC)\r
556 telnet->state = SEENIAC;\r
557 else {\r
558 if (!telnet->in_synch)\r
559 ADDTOBUF(c);\r
560 \r
561 #if 1\r
562 /* I can't get the F***ing winsock to insert the urgent IAC\r
563 * into the right position! Even with SO_OOBINLINE it gives\r
564 * it to recv too soon. And of course the DM byte (that\r
565 * arrives in the same packet!) appears several K later!!\r
566 *\r
567 * Oh well, we do get the DM in the right place so I'll\r
568 * just stop hiding on the next 0xf2 and hope for the best.\r
569 */\r
570 else if (c == DM)\r
571 telnet->in_synch = 0;\r
572 #endif\r
573 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)\r
574 telnet->state = SEENCR;\r
575 else\r
576 telnet->state = TOP_LEVEL;\r
577 }\r
578 break;\r
579 case SEENIAC:\r
580 if (c == DO)\r
581 telnet->state = SEENDO;\r
582 else if (c == DONT)\r
583 telnet->state = SEENDONT;\r
584 else if (c == WILL)\r
585 telnet->state = SEENWILL;\r
586 else if (c == WONT)\r
587 telnet->state = SEENWONT;\r
588 else if (c == SB)\r
589 telnet->state = SEENSB;\r
590 else if (c == DM) {\r
591 telnet->in_synch = 0;\r
592 telnet->state = TOP_LEVEL;\r
593 } else {\r
594 /* ignore everything else; print it if it's IAC */\r
595 if (c == IAC) {\r
596 ADDTOBUF(c);\r
597 }\r
598 telnet->state = TOP_LEVEL;\r
599 }\r
600 break;\r
601 case SEENWILL:\r
602 proc_rec_opt(telnet, WILL, c);\r
603 telnet->state = TOP_LEVEL;\r
604 break;\r
605 case SEENWONT:\r
606 proc_rec_opt(telnet, WONT, c);\r
607 telnet->state = TOP_LEVEL;\r
608 break;\r
609 case SEENDO:\r
610 proc_rec_opt(telnet, DO, c);\r
611 telnet->state = TOP_LEVEL;\r
612 break;\r
613 case SEENDONT:\r
614 proc_rec_opt(telnet, DONT, c);\r
615 telnet->state = TOP_LEVEL;\r
616 break;\r
617 case SEENSB:\r
618 telnet->sb_opt = c;\r
619 telnet->sb_len = 0;\r
620 telnet->state = SUBNEGOT;\r
621 break;\r
622 case SUBNEGOT:\r
623 if (c == IAC)\r
624 telnet->state = SUBNEG_IAC;\r
625 else {\r
626 subneg_addchar:\r
627 if (telnet->sb_len >= telnet->sb_size) {\r
628 telnet->sb_size += SB_DELTA;\r
629 telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,\r
630 unsigned char);\r
631 }\r
632 telnet->sb_buf[telnet->sb_len++] = c;\r
633 telnet->state = SUBNEGOT; /* in case we came here by goto */\r
634 }\r
635 break;\r
636 case SUBNEG_IAC:\r
637 if (c != SE)\r
638 goto subneg_addchar; /* yes, it's a hack, I know, but... */\r
639 else {\r
640 process_subneg(telnet);\r
641 telnet->state = TOP_LEVEL;\r
642 }\r
643 break;\r
644 }\r
645 }\r
646 \r
647 if (outbuflen)\r
648 c_write(telnet, outbuf, outbuflen);\r
649 sfree(outbuf);\r
650 }\r
651 \r
652 static void telnet_log(Plug plug, int type, SockAddr addr, int port,\r
653 const char *error_msg, int error_code)\r
654 {\r
655 Telnet telnet = (Telnet) plug;\r
656 backend_socket_log(telnet->frontend, type, addr, port,\r
657 error_msg, error_code, telnet->conf,\r
658 telnet->session_started);\r
659 }\r
660 \r
661 static void telnet_closing(Plug plug, const char *error_msg, int error_code,\r
662 int calling_back)\r
663 {\r
664 Telnet telnet = (Telnet) plug;\r
665 \r
666 /*\r
667 * We don't implement independent EOF in each direction for Telnet\r
668 * connections; as soon as we get word that the remote side has\r
669 * sent us EOF, we wind up the whole connection.\r
670 */\r
671 \r
672 if (telnet->s) {\r
673 sk_close(telnet->s);\r
674 telnet->s = NULL;\r
675 if (error_msg)\r
676 telnet->closed_on_socket_error = TRUE;\r
677 notify_remote_exit(telnet->frontend);\r
678 }\r
679 if (error_msg) {\r
680 logevent(telnet->frontend, error_msg);\r
681 connection_fatal(telnet->frontend, "%s", error_msg);\r
682 }\r
683 /* Otherwise, the remote side closed the connection normally. */\r
684 }\r
685 \r
686 static void telnet_receive(Plug plug, int urgent, char *data, int len)\r
687 {\r
688 Telnet telnet = (Telnet) plug;\r
689 if (urgent)\r
690 telnet->in_synch = TRUE;\r
691 telnet->session_started = TRUE;\r
692 do_telnet_read(telnet, data, len);\r
693 }\r
694 \r
695 static void telnet_sent(Plug plug, int bufsize)\r
696 {\r
697 Telnet telnet = (Telnet) plug;\r
698 telnet->bufsize = bufsize;\r
699 }\r
700 \r
701 /*\r
702 * Called to set up the Telnet connection.\r
703 *\r
704 * Returns an error message, or NULL on success.\r
705 *\r
706 * Also places the canonical host name into `realhost'. It must be\r
707 * freed by the caller.\r
708 */\r
709 static const char *telnet_init(void *frontend_handle, void **backend_handle,\r
710 Conf *conf, const char *host, int port,\r
711 char **realhost, int nodelay, int keepalive)\r
712 {\r
713 static const struct plug_function_table fn_table = {\r
714 telnet_log,\r
715 telnet_closing,\r
716 telnet_receive,\r
717 telnet_sent\r
718 };\r
719 SockAddr addr;\r
720 const char *err;\r
721 Telnet telnet;\r
722 char *loghost;\r
723 int addressfamily;\r
724 \r
725 telnet = snew(struct telnet_tag);\r
726 telnet->fn = &fn_table;\r
727 telnet->conf = conf_copy(conf);\r
728 telnet->s = NULL;\r
729 telnet->closed_on_socket_error = FALSE;\r
730 telnet->echoing = TRUE;\r
731 telnet->editing = TRUE;\r
732 telnet->activated = FALSE;\r
733 telnet->sb_buf = NULL;\r
734 telnet->sb_size = 0;\r
735 telnet->frontend = frontend_handle;\r
736 telnet->term_width = conf_get_int(telnet->conf, CONF_width);\r
737 telnet->term_height = conf_get_int(telnet->conf, CONF_height);\r
738 telnet->state = TOP_LEVEL;\r
739 telnet->ldisc = NULL;\r
740 telnet->pinger = NULL;\r
741 telnet->session_started = TRUE;\r
742 *backend_handle = telnet;\r
743 \r
744 /*\r
745 * Try to find host.\r
746 */\r
747 addressfamily = conf_get_int(telnet->conf, CONF_addressfamily);\r
748 addr = name_lookup(host, port, realhost, telnet->conf, addressfamily,\r
749 telnet->frontend, "Telnet connection");\r
750 if ((err = sk_addr_error(addr)) != NULL) {\r
751 sk_addr_free(addr);\r
752 return err;\r
753 }\r
754 \r
755 if (port < 0)\r
756 port = 23; /* default telnet port */\r
757 \r
758 /*\r
759 * Open socket.\r
760 */\r
761 telnet->s = new_connection(addr, *realhost, port, 0, 1,\r
762 nodelay, keepalive, (Plug) telnet, telnet->conf);\r
763 if ((err = sk_socket_error(telnet->s)) != NULL)\r
764 return err;\r
765 \r
766 telnet->pinger = pinger_new(telnet->conf, &telnet_backend, telnet);\r
767 \r
768 /*\r
769 * Initialise option states.\r
770 */\r
771 if (conf_get_int(telnet->conf, CONF_passive_telnet)) {\r
772 const struct Opt *const *o;\r
773 \r
774 for (o = opts; *o; o++)\r
775 telnet->opt_states[(*o)->index] = INACTIVE;\r
776 } else {\r
777 const struct Opt *const *o;\r
778 \r
779 for (o = opts; *o; o++) {\r
780 telnet->opt_states[(*o)->index] = (*o)->initial_state;\r
781 if (telnet->opt_states[(*o)->index] == REQUESTED)\r
782 send_opt(telnet, (*o)->send, (*o)->option);\r
783 }\r
784 telnet->activated = TRUE;\r
785 }\r
786 \r
787 /*\r
788 * Set up SYNCH state.\r
789 */\r
790 telnet->in_synch = FALSE;\r
791 \r
792 /*\r
793 * We can send special commands from the start.\r
794 */\r
795 update_specials_menu(telnet->frontend);\r
796 \r
797 /*\r
798 * loghost overrides realhost, if specified.\r
799 */\r
800 loghost = conf_get_str(telnet->conf, CONF_loghost);\r
801 if (*loghost) {\r
802 char *colon;\r
803 \r
804 sfree(*realhost);\r
805 *realhost = dupstr(loghost);\r
806 \r
807 colon = host_strrchr(*realhost, ':');\r
808 if (colon)\r
809 *colon++ = '\0';\r
810 }\r
811 \r
812 return NULL;\r
813 }\r
814 \r
815 static void telnet_free(void *handle)\r
816 {\r
817 Telnet telnet = (Telnet) handle;\r
818 \r
819 sfree(telnet->sb_buf);\r
820 if (telnet->s)\r
821 sk_close(telnet->s);\r
822 if (telnet->pinger)\r
823 pinger_free(telnet->pinger);\r
824 conf_free(telnet->conf);\r
825 sfree(telnet);\r
826 }\r
827 /*\r
828 * Reconfigure the Telnet backend. There's no immediate action\r
829 * necessary, in this backend: we just save the fresh config for\r
830 * any subsequent negotiations.\r
831 */\r
832 static void telnet_reconfig(void *handle, Conf *conf)\r
833 {\r
834 Telnet telnet = (Telnet) handle;\r
835 pinger_reconfig(telnet->pinger, telnet->conf, conf);\r
836 conf_free(telnet->conf);\r
837 telnet->conf = conf_copy(conf);\r
838 }\r
839 \r
840 /*\r
841 * Called to send data down the Telnet connection.\r
842 */\r
843 static int telnet_send(void *handle, const char *buf, int len)\r
844 {\r
845 Telnet telnet = (Telnet) handle;\r
846 unsigned char *p, *end;\r
847 static const unsigned char iac[2] = { IAC, IAC };\r
848 static const unsigned char cr[2] = { CR, NUL };\r
849 #if 0\r
850 static const unsigned char nl[2] = { CR, LF };\r
851 #endif\r
852 \r
853 if (telnet->s == NULL)\r
854 return 0;\r
855 \r
856 p = (unsigned char *)buf;\r
857 end = (unsigned char *)(buf + len);\r
858 while (p < end) {\r
859 unsigned char *q = p;\r
860 \r
861 while (p < end && iswritable(*p))\r
862 p++;\r
863 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);\r
864 \r
865 while (p < end && !iswritable(*p)) {\r
866 telnet->bufsize = \r
867 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);\r
868 p++;\r
869 }\r
870 }\r
871 \r
872 return telnet->bufsize;\r
873 }\r
874 \r
875 /*\r
876 * Called to query the current socket sendability status.\r
877 */\r
878 static int telnet_sendbuffer(void *handle)\r
879 {\r
880 Telnet telnet = (Telnet) handle;\r
881 return telnet->bufsize;\r
882 }\r
883 \r
884 /*\r
885 * Called to set the size of the window from Telnet's POV.\r
886 */\r
887 static void telnet_size(void *handle, int width, int height)\r
888 {\r
889 Telnet telnet = (Telnet) handle;\r
890 unsigned char b[24];\r
891 int n;\r
892 char *logbuf;\r
893 \r
894 telnet->term_width = width;\r
895 telnet->term_height = height;\r
896 \r
897 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)\r
898 return;\r
899 n = 0;\r
900 b[n++] = IAC;\r
901 b[n++] = SB;\r
902 b[n++] = TELOPT_NAWS;\r
903 b[n++] = telnet->term_width >> 8;\r
904 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
905 b[n++] = telnet->term_width & 0xFF;\r
906 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
907 b[n++] = telnet->term_height >> 8;\r
908 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
909 b[n++] = telnet->term_height & 0xFF;\r
910 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
911 b[n++] = IAC;\r
912 b[n++] = SE;\r
913 telnet->bufsize = sk_write(telnet->s, (char *)b, n);\r
914 logbuf = dupprintf("client:\tSB NAWS %d,%d",\r
915 telnet->term_width, telnet->term_height);\r
916 logevent(telnet->frontend, logbuf);\r
917 sfree(logbuf);\r
918 }\r
919 \r
920 /*\r
921 * Send Telnet special codes.\r
922 */\r
923 static void telnet_special(void *handle, Telnet_Special code)\r
924 {\r
925 Telnet telnet = (Telnet) handle;\r
926 unsigned char b[2];\r
927 \r
928 if (telnet->s == NULL)\r
929 return;\r
930 \r
931 b[0] = IAC;\r
932 switch (code) {\r
933 case TS_AYT:\r
934 b[1] = AYT;\r
935 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
936 break;\r
937 case TS_BRK:\r
938 b[1] = BREAK;\r
939 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
940 break;\r
941 case TS_EC:\r
942 b[1] = EC;\r
943 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
944 break;\r
945 case TS_EL:\r
946 b[1] = EL;\r
947 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
948 break;\r
949 case TS_GA:\r
950 b[1] = GA;\r
951 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
952 break;\r
953 case TS_NOP:\r
954 b[1] = NOP;\r
955 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
956 break;\r
957 case TS_ABORT:\r
958 b[1] = ABORT;\r
959 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
960 break;\r
961 case TS_AO:\r
962 b[1] = AO;\r
963 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
964 break;\r
965 case TS_IP:\r
966 b[1] = IP;\r
967 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
968 break;\r
969 case TS_SUSP:\r
970 b[1] = SUSP;\r
971 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
972 break;\r
973 case TS_EOR:\r
974 b[1] = EOR;\r
975 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
976 break;\r
977 case TS_EOF:\r
978 b[1] = xEOF;\r
979 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
980 break;\r
981 case TS_EOL:\r
982 /* In BINARY mode, CR-LF becomes just CR -\r
983 * and without the NUL suffix too. */\r
984 if (telnet->opt_states[o_we_bin.index] == ACTIVE)\r
985 telnet->bufsize = sk_write(telnet->s, "\r", 1);\r
986 else\r
987 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);\r
988 break;\r
989 case TS_SYNCH:\r
990 b[1] = DM;\r
991 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);\r
992 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);\r
993 break;\r
994 case TS_RECHO:\r
995 if (telnet->opt_states[o_echo.index] == INACTIVE ||\r
996 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {\r
997 telnet->opt_states[o_echo.index] = REQUESTED;\r
998 send_opt(telnet, o_echo.send, o_echo.option);\r
999 }\r
1000 break;\r
1001 case TS_LECHO:\r
1002 if (telnet->opt_states[o_echo.index] == ACTIVE) {\r
1003 telnet->opt_states[o_echo.index] = REQUESTED;\r
1004 send_opt(telnet, o_echo.nsend, o_echo.option);\r
1005 }\r
1006 break;\r
1007 case TS_PING:\r
1008 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {\r
1009 b[1] = NOP;\r
1010 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
1011 }\r
1012 break;\r
1013 default:\r
1014 break; /* never heard of it */\r
1015 }\r
1016 }\r
1017 \r
1018 static const struct telnet_special *telnet_get_specials(void *handle)\r
1019 {\r
1020 static const struct telnet_special specials[] = {\r
1021 {"Are You There", TS_AYT},\r
1022 {"Break", TS_BRK},\r
1023 {"Synch", TS_SYNCH},\r
1024 {"Erase Character", TS_EC},\r
1025 {"Erase Line", TS_EL},\r
1026 {"Go Ahead", TS_GA},\r
1027 {"No Operation", TS_NOP},\r
1028 {NULL, TS_SEP},\r
1029 {"Abort Process", TS_ABORT},\r
1030 {"Abort Output", TS_AO},\r
1031 {"Interrupt Process", TS_IP},\r
1032 {"Suspend Process", TS_SUSP},\r
1033 {NULL, TS_SEP},\r
1034 {"End Of Record", TS_EOR},\r
1035 {"End Of File", TS_EOF},\r
1036 {NULL, TS_EXITMENU}\r
1037 };\r
1038 return specials;\r
1039 }\r
1040 \r
1041 static int telnet_connected(void *handle)\r
1042 {\r
1043 Telnet telnet = (Telnet) handle;\r
1044 return telnet->s != NULL;\r
1045 }\r
1046 \r
1047 static int telnet_sendok(void *handle)\r
1048 {\r
1049 /* Telnet telnet = (Telnet) handle; */\r
1050 return 1;\r
1051 }\r
1052 \r
1053 static void telnet_unthrottle(void *handle, int backlog)\r
1054 {\r
1055 Telnet telnet = (Telnet) handle;\r
1056 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);\r
1057 }\r
1058 \r
1059 static int telnet_ldisc(void *handle, int option)\r
1060 {\r
1061 Telnet telnet = (Telnet) handle;\r
1062 if (option == LD_ECHO)\r
1063 return telnet->echoing;\r
1064 if (option == LD_EDIT)\r
1065 return telnet->editing;\r
1066 return FALSE;\r
1067 }\r
1068 \r
1069 static void telnet_provide_ldisc(void *handle, void *ldisc)\r
1070 {\r
1071 Telnet telnet = (Telnet) handle;\r
1072 telnet->ldisc = ldisc;\r
1073 }\r
1074 \r
1075 static void telnet_provide_logctx(void *handle, void *logctx)\r
1076 {\r
1077 /* This is a stub. */\r
1078 }\r
1079 \r
1080 static int telnet_exitcode(void *handle)\r
1081 {\r
1082 Telnet telnet = (Telnet) handle;\r
1083 if (telnet->s != NULL)\r
1084 return -1; /* still connected */\r
1085 else if (telnet->closed_on_socket_error)\r
1086 return INT_MAX; /* a socket error counts as an unclean exit */\r
1087 else\r
1088 /* Telnet doesn't transmit exit codes back to the client */\r
1089 return 0;\r
1090 }\r
1091 \r
1092 /*\r
1093 * cfg_info for Telnet does nothing at all.\r
1094 */\r
1095 static int telnet_cfg_info(void *handle)\r
1096 {\r
1097 return 0;\r
1098 }\r
1099 \r
1100 Backend telnet_backend = {\r
1101 telnet_init,\r
1102 telnet_free,\r
1103 telnet_reconfig,\r
1104 telnet_send,\r
1105 telnet_sendbuffer,\r
1106 telnet_size,\r
1107 telnet_special,\r
1108 telnet_get_specials,\r
1109 telnet_connected,\r
1110 telnet_exitcode,\r
1111 telnet_sendok,\r
1112 telnet_ldisc,\r
1113 telnet_provide_ldisc,\r
1114 telnet_provide_logctx,\r
1115 telnet_unthrottle,\r
1116 telnet_cfg_info,\r
1117 NULL /* test_for_upstream */,\r
1118 "telnet",\r
1119 PROT_TELNET,\r
1120 23\r
1121 };\r