| blob | 8580bee0c16b68940064099c5de63b4aae4f8a52 |
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 TELOPT_BINARY 0 /* 8-bit data path */\r
40 #define TELOPT_ECHO 1 /* echo */\r
41 #define TELOPT_RCP 2 /* prepare to reconnect */\r
42 #define TELOPT_SGA 3 /* suppress go ahead */\r
43 #define TELOPT_NAMS 4 /* approximate message size */\r
44 #define TELOPT_STATUS 5 /* give status */\r
45 #define TELOPT_TM 6 /* timing mark */\r
46 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */\r
47 #define TELOPT_NAOL 8 /* negotiate about output line width */\r
48 #define TELOPT_NAOP 9 /* negotiate about output page size */\r
49 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */\r
50 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */\r
51 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */\r
52 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */\r
53 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */\r
54 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */\r
55 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */\r
56 #define TELOPT_XASCII 17 /* extended ascic character set */\r
57 #define TELOPT_LOGOUT 18 /* force logout */\r
58 #define TELOPT_BM 19 /* byte macro */\r
59 #define TELOPT_DET 20 /* data entry terminal */\r
60 #define TELOPT_SUPDUP 21 /* supdup protocol */\r
61 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */\r
62 #define TELOPT_SNDLOC 23 /* send location */\r
63 #define TELOPT_TTYPE 24 /* terminal type */\r
64 #define TELOPT_EOR 25 /* end or record */\r
65 #define TELOPT_TUID 26 /* TACACS user identification */\r
66 #define TELOPT_OUTMRK 27 /* output marking */\r
67 #define TELOPT_TTYLOC 28 /* terminal location number */\r
68 #define TELOPT_3270REGIME 29 /* 3270 regime */\r
69 #define TELOPT_X3PAD 30 /* X.3 PAD */\r
70 #define TELOPT_NAWS 31 /* window size */\r
71 #define TELOPT_TSPEED 32 /* terminal speed */\r
72 #define TELOPT_LFLOW 33 /* remote flow control */\r
73 #define TELOPT_LINEMODE 34 /* Linemode option */\r
74 #define TELOPT_XDISPLOC 35 /* X Display Location */\r
75 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */\r
76 #define TELOPT_AUTHENTICATION 37 /* Authenticate */\r
77 #define TELOPT_ENCRYPT 38 /* Encryption option */\r
78 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */\r
79 #define TELOPT_TN3270E 40 /* TN3270 enhancements */\r
80 #define TELOPT_XAUTH 41\r
81 #define TELOPT_CHARSET 42 /* Character set */\r
82 #define TELOPT_RSP 43 /* Remote serial port */\r
83 #define TELOPT_COM_PORT_OPTION 44 /* Com port control */\r
84 #define TELOPT_SLE 45 /* Suppress local echo */\r
85 #define TELOPT_STARTTLS 46 /* Start TLS */\r
86 #define TELOPT_KERMIT 47 /* Automatic Kermit file transfer */\r
87 #define TELOPT_SEND_URL 48\r
88 #define TELOPT_FORWARD_X 49\r
89 #define TELOPT_PRAGMA_LOGON 138\r
90 #define TELOPT_SSPI_LOGON 139\r
91 #define TELOPT_PRAGMA_HEARTBEAT 140\r
92 #define TELOPT_EXOPL 255 /* extended-options-list */\r
93 \r
94 #define TELQUAL_IS 0 /* option is... */\r
95 #define TELQUAL_SEND 1 /* send option */\r
96 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */\r
97 #define BSD_VAR 1\r
98 #define BSD_VALUE 0\r
99 #define RFC_VAR 0\r
100 #define RFC_VALUE 1\r
101 \r
102 #define CR 13\r
103 #define LF 10\r
104 #define NUL 0\r
105 \r
106 #define iswritable(x) \\r
107 ( (x) != IAC && \\r
108 (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))\r
109 \r
110 static char *telopt(int opt)\r
111 {\r
112 #define i(x) if (opt == TELOPT_ ## x) return #x;\r
113 i(BINARY);\r
114 i(ECHO);\r
115 i(RCP);\r
116 i(SGA);\r
117 i(NAMS);\r
118 i(STATUS);\r
119 i(TM);\r
120 i(RCTE);\r
121 i(NAOL);\r
122 i(NAOP);\r
123 i(NAOCRD);\r
124 i(NAOHTS);\r
125 i(NAOHTD);\r
126 i(NAOFFD);\r
127 i(NAOVTS);\r
128 i(NAOVTD);\r
129 i(NAOLFD);\r
130 i(XASCII);\r
131 i(LOGOUT);\r
132 i(BM);\r
133 i(DET);\r
134 i(SUPDUP);\r
135 i(SUPDUPOUTPUT);\r
136 i(SNDLOC);\r
137 i(TTYPE);\r
138 i(EOR);\r
139 i(TUID);\r
140 i(OUTMRK);\r
141 i(TTYLOC);\r
142 i(X3PAD);\r
143 i(NAWS);\r
144 i(TSPEED);\r
145 i(LFLOW);\r
146 i(LINEMODE);\r
147 i(XDISPLOC);\r
148 i(OLD_ENVIRON);\r
149 i(AUTHENTICATION);\r
150 i(ENCRYPT);\r
151 i(NEW_ENVIRON);\r
152 i(TN3270E);\r
153 i(XAUTH);\r
154 i(CHARSET);\r
155 i(RSP);\r
156 i(COM_PORT_OPTION);\r
157 i(SLE);\r
158 i(STARTTLS);\r
159 i(KERMIT);\r
160 i(SEND_URL);\r
161 i(FORWARD_X);\r
162 i(PRAGMA_LOGON);\r
163 i(SSPI_LOGON);\r
164 i(PRAGMA_HEARTBEAT);\r
165 i(EXOPL);\r
166 #undef i\r
167 return "<unknown>";\r
168 }\r
169 \r
170 static void telnet_size(void *handle, int width, int height);\r
171 \r
172 struct Opt {\r
173 int send; /* what we initially send */\r
174 int nsend; /* -ve send if requested to stop it */\r
175 int ack, nak; /* +ve and -ve acknowledgements */\r
176 int option; /* the option code */\r
177 int index; /* index into telnet->opt_states[] */\r
178 enum {\r
179 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE\r
180 } initial_state;\r
181 };\r
182 \r
183 enum {\r
184 OPTINDEX_NAWS,\r
185 OPTINDEX_TSPEED,\r
186 OPTINDEX_TTYPE,\r
187 OPTINDEX_OENV,\r
188 OPTINDEX_NENV,\r
189 OPTINDEX_ECHO,\r
190 OPTINDEX_WE_SGA,\r
191 OPTINDEX_THEY_SGA,\r
192 OPTINDEX_WE_BIN,\r
193 OPTINDEX_THEY_BIN,\r
194 NUM_OPTS\r
195 };\r
196 \r
197 static const struct Opt o_naws =\r
198 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };\r
199 static const struct Opt o_tspeed =\r
200 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };\r
201 static const struct Opt o_ttype =\r
202 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };\r
203 static const struct Opt o_oenv =\r
204 { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };\r
205 static const struct Opt o_nenv =\r
206 { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };\r
207 static const struct Opt o_echo =\r
208 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };\r
209 static const struct Opt o_we_sga =\r
210 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };\r
211 static const struct Opt o_they_sga =\r
212 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };\r
213 static const struct Opt o_we_bin =\r
214 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };\r
215 static const struct Opt o_they_bin =\r
216 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };\r
217 \r
218 static const struct Opt *const opts[] = {\r
219 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,\r
220 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL\r
221 };\r
222 \r
223 typedef struct telnet_tag {\r
224 const struct plug_function_table *fn;\r
225 /* the above field _must_ be first in the structure */\r
226 \r
227 Socket s;\r
228 \r
229 void *frontend;\r
230 void *ldisc;\r
231 int term_width, term_height;\r
232 \r
233 int opt_states[NUM_OPTS];\r
234 \r
235 int echoing, editing;\r
236 int activated;\r
237 int bufsize;\r
238 int in_synch;\r
239 int sb_opt, sb_len;\r
240 unsigned char *sb_buf;\r
241 int sb_size;\r
242 \r
243 enum {\r
244 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,\r
245 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR\r
246 } state;\r
247 \r
248 Config cfg;\r
249 \r
250 Pinger pinger;\r
251 } *Telnet;\r
252 \r
253 #define TELNET_MAX_BACKLOG 4096\r
254 \r
255 #define SB_DELTA 1024\r
256 \r
257 static void c_write(Telnet telnet, char *buf, int len)\r
258 {\r
259 int backlog;\r
260 backlog = from_backend(telnet->frontend, 0, buf, len);\r
261 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);\r
262 }\r
263 \r
264 static void log_option(Telnet telnet, char *sender, int cmd, int option)\r
265 {\r
266 char *buf;\r
267 /*\r
268 * The strange-looking "<?""?>" below is there to avoid a\r
269 * trigraph - a double question mark followed by > maps to a\r
270 * closing brace character!\r
271 */\r
272 buf = dupprintf("%s:\t%s %s", sender,\r
273 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :\r
274 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),\r
275 telopt(option));\r
276 logevent(telnet->frontend, buf);\r
277 sfree(buf);\r
278 }\r
279 \r
280 static void send_opt(Telnet telnet, int cmd, int option)\r
281 {\r
282 unsigned char b[3];\r
283 \r
284 b[0] = IAC;\r
285 b[1] = cmd;\r
286 b[2] = option;\r
287 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);\r
288 log_option(telnet, "client", cmd, option);\r
289 }\r
290 \r
291 static void deactivate_option(Telnet telnet, const struct Opt *o)\r
292 {\r
293 if (telnet->opt_states[o->index] == REQUESTED ||\r
294 telnet->opt_states[o->index] == ACTIVE)\r
295 send_opt(telnet, o->nsend, o->option);\r
296 telnet->opt_states[o->index] = REALLY_INACTIVE;\r
297 }\r
298 \r
299 /*\r
300 * Generate side effects of enabling or disabling an option.\r
301 */\r
302 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)\r
303 {\r
304 if (o->option == TELOPT_ECHO && o->send == DO)\r
305 telnet->echoing = !enabled;\r
306 else if (o->option == TELOPT_SGA && o->send == DO)\r
307 telnet->editing = !enabled;\r
308 if (telnet->ldisc) /* cause ldisc to notice the change */\r
309 ldisc_send(telnet->ldisc, NULL, 0, 0);\r
310 \r
311 /* Ensure we get the minimum options */\r
312 if (!telnet->activated) {\r
313 if (telnet->opt_states[o_echo.index] == INACTIVE) {\r
314 telnet->opt_states[o_echo.index] = REQUESTED;\r
315 send_opt(telnet, o_echo.send, o_echo.option);\r
316 }\r
317 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {\r
318 telnet->opt_states[o_we_sga.index] = REQUESTED;\r
319 send_opt(telnet, o_we_sga.send, o_we_sga.option);\r
320 }\r
321 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {\r
322 telnet->opt_states[o_they_sga.index] = REQUESTED;\r
323 send_opt(telnet, o_they_sga.send, o_they_sga.option);\r
324 }\r
325 telnet->activated = TRUE;\r
326 }\r
327 }\r
328 \r
329 static void activate_option(Telnet telnet, const struct Opt *o)\r
330 {\r
331 if (o->send == WILL && o->option == TELOPT_NAWS)\r
332 telnet_size(telnet, telnet->term_width, telnet->term_height);\r
333 if (o->send == WILL &&\r
334 (o->option == TELOPT_NEW_ENVIRON ||\r
335 o->option == TELOPT_OLD_ENVIRON)) {\r
336 /*\r
337 * We may only have one kind of ENVIRON going at a time.\r
338 * This is a hack, but who cares.\r
339 */\r
340 deactivate_option(telnet, o->option ==\r
341 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);\r
342 }\r
343 option_side_effects(telnet, o, 1);\r
344 }\r
345 \r
346 static void refused_option(Telnet telnet, const struct Opt *o)\r
347 {\r
348 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&\r
349 telnet->opt_states[o_oenv.index] == INACTIVE) {\r
350 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);\r
351 telnet->opt_states[o_oenv.index] = REQUESTED;\r
352 }\r
353 option_side_effects(telnet, o, 0);\r
354 }\r
355 \r
356 static void proc_rec_opt(Telnet telnet, int cmd, int option)\r
357 {\r
358 const struct Opt *const *o;\r
359 \r
360 log_option(telnet, "server", cmd, option);\r
361 for (o = opts; *o; o++) {\r
362 if ((*o)->option == option && (*o)->ack == cmd) {\r
363 switch (telnet->opt_states[(*o)->index]) {\r
364 case REQUESTED:\r
365 telnet->opt_states[(*o)->index] = ACTIVE;\r
366 activate_option(telnet, *o);\r
367 break;\r
368 case ACTIVE:\r
369 break;\r
370 case INACTIVE:\r
371 telnet->opt_states[(*o)->index] = ACTIVE;\r
372 send_opt(telnet, (*o)->send, option);\r
373 activate_option(telnet, *o);\r
374 break;\r
375 case REALLY_INACTIVE:\r
376 send_opt(telnet, (*o)->nsend, option);\r
377 break;\r
378 }\r
379 return;\r
380 } else if ((*o)->option == option && (*o)->nak == cmd) {\r
381 switch (telnet->opt_states[(*o)->index]) {\r
382 case REQUESTED:\r
383 telnet->opt_states[(*o)->index] = INACTIVE;\r
384 refused_option(telnet, *o);\r
385 break;\r
386 case ACTIVE:\r
387 telnet->opt_states[(*o)->index] = INACTIVE;\r
388 send_opt(telnet, (*o)->nsend, option);\r
389 option_side_effects(telnet, *o, 0);\r
390 break;\r
391 case INACTIVE:\r
392 case REALLY_INACTIVE:\r
393 break;\r
394 }\r
395 return;\r
396 }\r
397 }\r
398 /*\r
399 * If we reach here, the option was one we weren't prepared to\r
400 * cope with. If the request was positive (WILL or DO), we send\r
401 * a negative ack to indicate refusal. If the request was\r
402 * negative (WONT / DONT), we must do nothing.\r
403 */\r
404 if (cmd == WILL || cmd == DO)\r
405 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);\r
406 }\r
407 \r
408 static void process_subneg(Telnet telnet)\r
409 {\r
410 unsigned char b[2048], *p, *q;\r
411 int var, value, n;\r
412 char *e;\r
413 \r
414 switch (telnet->sb_opt) {\r
415 case TELOPT_TSPEED:\r
416 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {\r
417 char *logbuf;\r
418 b[0] = IAC;\r
419 b[1] = SB;\r
420 b[2] = TELOPT_TSPEED;\r
421 b[3] = TELQUAL_IS;\r
422 strcpy((char *)(b + 4), telnet->cfg.termspeed);\r
423 n = 4 + strlen(telnet->cfg.termspeed);\r
424 b[n] = IAC;\r
425 b[n + 1] = SE;\r
426 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);\r
427 logevent(telnet->frontend, "server:\tSB TSPEED SEND");\r
428 logbuf = dupprintf("client:\tSB TSPEED IS %s", telnet->cfg.termspeed);\r
429 logevent(telnet->frontend, logbuf);\r
430 sfree(logbuf);\r
431 } else\r
432 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");\r
433 break;\r
434 case TELOPT_TTYPE:\r
435 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {\r
436 char *logbuf;\r
437 b[0] = IAC;\r
438 b[1] = SB;\r
439 b[2] = TELOPT_TTYPE;\r
440 b[3] = TELQUAL_IS;\r
441 for (n = 0; telnet->cfg.termtype[n]; n++)\r
442 b[n + 4] = (telnet->cfg.termtype[n] >= 'a'\r
443 && telnet->cfg.termtype[n] <=\r
444 'z' ? telnet->cfg.termtype[n] + 'A' -\r
445 'a' : telnet->cfg.termtype[n]);\r
446 b[n + 4] = IAC;\r
447 b[n + 5] = SE;\r
448 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);\r
449 b[n + 4] = 0;\r
450 logevent(telnet->frontend, "server:\tSB TTYPE SEND");\r
451 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);\r
452 logevent(telnet->frontend, logbuf);\r
453 sfree(logbuf);\r
454 } else\r
455 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");\r
456 break;\r
457 case TELOPT_OLD_ENVIRON:\r
458 case TELOPT_NEW_ENVIRON:\r
459 p = telnet->sb_buf;\r
460 q = p + telnet->sb_len;\r
461 if (p < q && *p == TELQUAL_SEND) {\r
462 char *logbuf;\r
463 p++;\r
464 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));\r
465 logevent(telnet->frontend, logbuf);\r
466 sfree(logbuf);\r
467 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {\r
468 if (telnet->cfg.rfc_environ) {\r
469 value = RFC_VALUE;\r
470 var = RFC_VAR;\r
471 } else {\r
472 value = BSD_VALUE;\r
473 var = BSD_VAR;\r
474 }\r
475 /*\r
476 * Try to guess the sense of VAR and VALUE.\r
477 */\r
478 while (p < q) {\r
479 if (*p == RFC_VAR) {\r
480 value = RFC_VALUE;\r
481 var = RFC_VAR;\r
482 } else if (*p == BSD_VAR) {\r
483 value = BSD_VALUE;\r
484 var = BSD_VAR;\r
485 }\r
486 p++;\r
487 }\r
488 } else {\r
489 /*\r
490 * With NEW_ENVIRON, the sense of VAR and VALUE\r
491 * isn't in doubt.\r
492 */\r
493 value = RFC_VALUE;\r
494 var = RFC_VAR;\r
495 }\r
496 b[0] = IAC;\r
497 b[1] = SB;\r
498 b[2] = telnet->sb_opt;\r
499 b[3] = TELQUAL_IS;\r
500 n = 4;\r
501 e = telnet->cfg.environmt;\r
502 while (*e) {\r
503 b[n++] = var;\r
504 while (*e && *e != '\t')\r
505 b[n++] = *e++;\r
506 if (*e == '\t')\r
507 e++;\r
508 b[n++] = value;\r
509 while (*e)\r
510 b[n++] = *e++;\r
511 e++;\r
512 }\r
513 if (*telnet->cfg.username) {\r
514 b[n++] = var;\r
515 b[n++] = 'U';\r
516 b[n++] = 'S';\r
517 b[n++] = 'E';\r
518 b[n++] = 'R';\r
519 b[n++] = value;\r
520 e = telnet->cfg.username;\r
521 while (*e)\r
522 b[n++] = *e++;\r
523 }\r
524 b[n++] = IAC;\r
525 b[n++] = SE;\r
526 telnet->bufsize = sk_write(telnet->s, (char *)b, n);\r
527 logbuf = dupprintf("client:\tSB %s IS %s%s%s%s",\r
528 telopt(telnet->sb_opt),\r
529 *telnet->cfg.username ? "USER=" : "",\r
530 telnet->cfg.username,\r
531 *telnet->cfg.username ? " " : "",\r
532 n == 6 ? "<nothing>" :\r
533 (*telnet->cfg.environmt ? "<stuff>" : ""));\r
534 logevent(telnet->frontend, logbuf);\r
535 sfree(logbuf);\r
536 }\r
537 break;\r
538 }\r
539 }\r
540 \r
541 static void do_telnet_read(Telnet telnet, char *buf, int len)\r
542 {\r
543 char *outbuf = NULL;\r
544 int outbuflen = 0, outbufsize = 0;\r
545 \r
546 #define ADDTOBUF(c) do { \\r
547 if (outbuflen >= outbufsize) { \\r
548 outbufsize = outbuflen + 256; \\r
549 outbuf = sresize(outbuf, outbufsize, char); \\r
550 } \\r
551 outbuf[outbuflen++] = (c); \\r
552 } while (0)\r
553 \r
554 while (len--) {\r
555 int c = (unsigned char) *buf++;\r
556 \r
557 switch (telnet->state) {\r
558 case TOP_LEVEL:\r
559 case SEENCR:\r
560 if (c == NUL && telnet->state == SEENCR)\r
561 telnet->state = TOP_LEVEL;\r
562 else if (c == IAC)\r
563 telnet->state = SEENIAC;\r
564 else {\r
565 if (!telnet->in_synch)\r
566 ADDTOBUF(c);\r
567 \r
568 #if 1\r
569 /* I can't get the F***ing winsock to insert the urgent IAC\r
570 * into the right position! Even with SO_OOBINLINE it gives\r
571 * it to recv too soon. And of course the DM byte (that\r
572 * arrives in the same packet!) appears several K later!!\r
573 *\r
574 * Oh well, we do get the DM in the right place so I'll\r
575 * just stop hiding on the next 0xf2 and hope for the best.\r
576 */\r
577 else if (c == DM)\r
578 telnet->in_synch = 0;\r
579 #endif\r
580 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)\r
581 telnet->state = SEENCR;\r
582 else\r
583 telnet->state = TOP_LEVEL;\r
584 }\r
585 break;\r
586 case SEENIAC:\r
587 if (c == DO)\r
588 telnet->state = SEENDO;\r
589 else if (c == DONT)\r
590 telnet->state = SEENDONT;\r
591 else if (c == WILL)\r
592 telnet->state = SEENWILL;\r
593 else if (c == WONT)\r
594 telnet->state = SEENWONT;\r
595 else if (c == SB)\r
596 telnet->state = SEENSB;\r
597 else if (c == DM) {\r
598 telnet->in_synch = 0;\r
599 telnet->state = TOP_LEVEL;\r
600 } else {\r
601 /* ignore everything else; print it if it's IAC */\r
602 if (c == IAC) {\r
603 ADDTOBUF(c);\r
604 }\r
605 telnet->state = TOP_LEVEL;\r
606 }\r
607 break;\r
608 case SEENWILL:\r
609 proc_rec_opt(telnet, WILL, c);\r
610 telnet->state = TOP_LEVEL;\r
611 break;\r
612 case SEENWONT:\r
613 proc_rec_opt(telnet, WONT, c);\r
614 telnet->state = TOP_LEVEL;\r
615 break;\r
616 case SEENDO:\r
617 proc_rec_opt(telnet, DO, c);\r
618 telnet->state = TOP_LEVEL;\r
619 break;\r
620 case SEENDONT:\r
621 proc_rec_opt(telnet, DONT, c);\r
622 telnet->state = TOP_LEVEL;\r
623 break;\r
624 case SEENSB:\r
625 telnet->sb_opt = c;\r
626 telnet->sb_len = 0;\r
627 telnet->state = SUBNEGOT;\r
628 break;\r
629 case SUBNEGOT:\r
630 if (c == IAC)\r
631 telnet->state = SUBNEG_IAC;\r
632 else {\r
633 subneg_addchar:\r
634 if (telnet->sb_len >= telnet->sb_size) {\r
635 telnet->sb_size += SB_DELTA;\r
636 telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,\r
637 unsigned char);\r
638 }\r
639 telnet->sb_buf[telnet->sb_len++] = c;\r
640 telnet->state = SUBNEGOT; /* in case we came here by goto */\r
641 }\r
642 break;\r
643 case SUBNEG_IAC:\r
644 if (c != SE)\r
645 goto subneg_addchar; /* yes, it's a hack, I know, but... */\r
646 else {\r
647 process_subneg(telnet);\r
648 telnet->state = TOP_LEVEL;\r
649 }\r
650 break;\r
651 }\r
652 }\r
653 \r
654 if (outbuflen)\r
655 c_write(telnet, outbuf, outbuflen);\r
656 sfree(outbuf);\r
657 }\r
658 \r
659 static void telnet_log(Plug plug, int type, SockAddr addr, int port,\r
660 const char *error_msg, int error_code)\r
661 {\r
662 Telnet telnet = (Telnet) plug;\r
663 char addrbuf[256], *msg;\r
664 \r
665 sk_getaddr(addr, addrbuf, lenof(addrbuf));\r
666 \r
667 if (type == 0)\r
668 msg = dupprintf("Connecting to %s port %d", addrbuf, port);\r
669 else\r
670 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);\r
671 \r
672 logevent(telnet->frontend, msg);\r
673 }\r
674 \r
675 static int telnet_closing(Plug plug, const char *error_msg, int error_code,\r
676 int calling_back)\r
677 {\r
678 Telnet telnet = (Telnet) plug;\r
679 \r
680 if (telnet->s) {\r
681 sk_close(telnet->s);\r
682 telnet->s = NULL;\r
683 notify_remote_exit(telnet->frontend);\r
684 }\r
685 if (error_msg) {\r
686 logevent(telnet->frontend, error_msg);\r
687 connection_fatal(telnet->frontend, "%s", error_msg);\r
688 }\r
689 /* Otherwise, the remote side closed the connection normally. */\r
690 return 0;\r
691 }\r
692 \r
693 static int telnet_receive(Plug plug, int urgent, char *data, int len)\r
694 {\r
695 Telnet telnet = (Telnet) plug;\r
696 if (urgent)\r
697 telnet->in_synch = TRUE;\r
698 do_telnet_read(telnet, data, len);\r
699 return 1;\r
700 }\r
701 \r
702 static void telnet_sent(Plug plug, int bufsize)\r
703 {\r
704 Telnet telnet = (Telnet) plug;\r
705 telnet->bufsize = bufsize;\r
706 }\r
707 \r
708 /*\r
709 * Called to set up the Telnet connection.\r
710 *\r
711 * Returns an error message, or NULL on success.\r
712 *\r
713 * Also places the canonical host name into `realhost'. It must be\r
714 * freed by the caller.\r
715 */\r
716 static const char *telnet_init(void *frontend_handle, void **backend_handle,\r
717 Config *cfg,\r
718 char *host, int port, char **realhost,\r
719 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 \r
731 telnet = snew(struct telnet_tag);\r
732 telnet->fn = &fn_table;\r
733 telnet->cfg = *cfg; /* STRUCTURE COPY */\r
734 telnet->s = NULL;\r
735 telnet->echoing = TRUE;\r
736 telnet->editing = TRUE;\r
737 telnet->activated = FALSE;\r
738 telnet->sb_buf = NULL;\r
739 telnet->sb_size = 0;\r
740 telnet->frontend = frontend_handle;\r
741 telnet->term_width = telnet->cfg.width;\r
742 telnet->term_height = telnet->cfg.height;\r
743 telnet->state = TOP_LEVEL;\r
744 telnet->ldisc = NULL;\r
745 telnet->pinger = NULL;\r
746 *backend_handle = telnet;\r
747 \r
748 /*\r
749 * Try to find host.\r
750 */\r
751 {\r
752 char *buf;\r
753 buf = dupprintf("Looking up host \"%s\"%s", host,\r
754 (cfg->addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :\r
755 (cfg->addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :\r
756 "")));\r
757 logevent(telnet->frontend, buf);\r
758 sfree(buf);\r
759 }\r
760 addr = name_lookup(host, port, realhost, &telnet->cfg, cfg->addressfamily);\r
761 if ((err = sk_addr_error(addr)) != NULL) {\r
762 sk_addr_free(addr);\r
763 return err;\r
764 }\r
765 \r
766 if (port < 0)\r
767 port = 23; /* default telnet port */\r
768 \r
769 /*\r
770 * Open socket.\r
771 */\r
772 telnet->s = new_connection(addr, *realhost, port, 0, 1,\r
773 nodelay, keepalive, (Plug) telnet, &telnet->cfg);\r
774 if ((err = sk_socket_error(telnet->s)) != NULL)\r
775 return err;\r
776 \r
777 telnet->pinger = pinger_new(&telnet->cfg, &telnet_backend, telnet);\r
778 \r
779 /*\r
780 * Initialise option states.\r
781 */\r
782 if (telnet->cfg.passive_telnet) {\r
783 const struct Opt *const *o;\r
784 \r
785 for (o = opts; *o; o++)\r
786 telnet->opt_states[(*o)->index] = INACTIVE;\r
787 } else {\r
788 const struct Opt *const *o;\r
789 \r
790 for (o = opts; *o; o++) {\r
791 telnet->opt_states[(*o)->index] = (*o)->initial_state;\r
792 if (telnet->opt_states[(*o)->index] == REQUESTED)\r
793 send_opt(telnet, (*o)->send, (*o)->option);\r
794 }\r
795 telnet->activated = TRUE;\r
796 }\r
797 \r
798 /*\r
799 * Set up SYNCH state.\r
800 */\r
801 telnet->in_synch = FALSE;\r
802 \r
803 /*\r
804 * We can send special commands from the start.\r
805 */\r
806 update_specials_menu(telnet->frontend);\r
807 \r
808 return NULL;\r
809 }\r
810 \r
811 static void telnet_free(void *handle)\r
812 {\r
813 Telnet telnet = (Telnet) handle;\r
814 \r
815 sfree(telnet->sb_buf);\r
816 if (telnet->s)\r
817 sk_close(telnet->s);\r
818 if (telnet->pinger)\r
819 pinger_free(telnet->pinger);\r
820 sfree(telnet);\r
821 }\r
822 /*\r
823 * Reconfigure the Telnet backend. There's no immediate action\r
824 * necessary, in this backend: we just save the fresh config for\r
825 * any subsequent negotiations.\r
826 */\r
827 static void telnet_reconfig(void *handle, Config *cfg)\r
828 {\r
829 Telnet telnet = (Telnet) handle;\r
830 pinger_reconfig(telnet->pinger, &telnet->cfg, cfg);\r
831 telnet->cfg = *cfg; /* STRUCTURE COPY */\r
832 }\r
833 \r
834 /*\r
835 * Called to send data down the Telnet connection.\r
836 */\r
837 static int telnet_send(void *handle, char *buf, int len)\r
838 {\r
839 Telnet telnet = (Telnet) handle;\r
840 unsigned char *p, *end;\r
841 static const unsigned char iac[2] = { IAC, IAC };\r
842 static const unsigned char cr[2] = { CR, NUL };\r
843 #if 0\r
844 static const unsigned char nl[2] = { CR, LF };\r
845 #endif\r
846 \r
847 if (telnet->s == NULL)\r
848 return 0;\r
849 \r
850 p = (unsigned char *)buf;\r
851 end = (unsigned char *)(buf + len);\r
852 while (p < end) {\r
853 unsigned char *q = p;\r
854 \r
855 while (p < end && iswritable(*p))\r
856 p++;\r
857 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);\r
858 \r
859 while (p < end && !iswritable(*p)) {\r
860 telnet->bufsize = \r
861 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);\r
862 p++;\r
863 }\r
864 }\r
865 \r
866 return telnet->bufsize;\r
867 }\r
868 \r
869 /*\r
870 * Called to query the current socket sendability status.\r
871 */\r
872 static int telnet_sendbuffer(void *handle)\r
873 {\r
874 Telnet telnet = (Telnet) handle;\r
875 return telnet->bufsize;\r
876 }\r
877 \r
878 /*\r
879 * Called to set the size of the window from Telnet's POV.\r
880 */\r
881 static void telnet_size(void *handle, int width, int height)\r
882 {\r
883 Telnet telnet = (Telnet) handle;\r
884 unsigned char b[24];\r
885 int n;\r
886 char *logbuf;\r
887 \r
888 telnet->term_width = width;\r
889 telnet->term_height = height;\r
890 \r
891 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)\r
892 return;\r
893 n = 0;\r
894 b[n++] = IAC;\r
895 b[n++] = SB;\r
896 b[n++] = TELOPT_NAWS;\r
897 b[n++] = telnet->term_width >> 8;\r
898 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
899 b[n++] = telnet->term_width & 0xFF;\r
900 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
901 b[n++] = telnet->term_height >> 8;\r
902 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
903 b[n++] = telnet->term_height & 0xFF;\r
904 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */\r
905 b[n++] = IAC;\r
906 b[n++] = SE;\r
907 telnet->bufsize = sk_write(telnet->s, (char *)b, n);\r
908 logbuf = dupprintf("client:\tSB NAWS %d,%d",\r
909 telnet->term_width, telnet->term_height);\r
910 logevent(telnet->frontend, logbuf);\r
911 sfree(logbuf);\r
912 }\r
913 \r
914 /*\r
915 * Send Telnet special codes.\r
916 */\r
917 static void telnet_special(void *handle, Telnet_Special code)\r
918 {\r
919 Telnet telnet = (Telnet) handle;\r
920 unsigned char b[2];\r
921 \r
922 if (telnet->s == NULL)\r
923 return;\r
924 \r
925 b[0] = IAC;\r
926 switch (code) {\r
927 case TS_AYT:\r
928 b[1] = AYT;\r
929 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
930 break;\r
931 case TS_BRK:\r
932 b[1] = BREAK;\r
933 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
934 break;\r
935 case TS_EC:\r
936 b[1] = EC;\r
937 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
938 break;\r
939 case TS_EL:\r
940 b[1] = EL;\r
941 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
942 break;\r
943 case TS_GA:\r
944 b[1] = GA;\r
945 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
946 break;\r
947 case TS_NOP:\r
948 b[1] = NOP;\r
949 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
950 break;\r
951 case TS_ABORT:\r
952 b[1] = ABORT;\r
953 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
954 break;\r
955 case TS_AO:\r
956 b[1] = AO;\r
957 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
958 break;\r
959 case TS_IP:\r
960 b[1] = IP;\r
961 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
962 break;\r
963 case TS_SUSP:\r
964 b[1] = SUSP;\r
965 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
966 break;\r
967 case TS_EOR:\r
968 b[1] = EOR;\r
969 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
970 break;\r
971 case TS_EOF:\r
972 b[1] = xEOF;\r
973 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
974 break;\r
975 case TS_EOL:\r
976 /* In BINARY mode, CR-LF becomes just CR -\r
977 * and without the NUL suffix too. */\r
978 if (telnet->opt_states[o_we_bin.index] == ACTIVE)\r
979 telnet->bufsize = sk_write(telnet->s, "\r", 1);\r
980 else\r
981 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);\r
982 break;\r
983 case TS_SYNCH:\r
984 b[1] = DM;\r
985 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);\r
986 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);\r
987 break;\r
988 case TS_RECHO:\r
989 if (telnet->opt_states[o_echo.index] == INACTIVE ||\r
990 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {\r
991 telnet->opt_states[o_echo.index] = REQUESTED;\r
992 send_opt(telnet, o_echo.send, o_echo.option);\r
993 }\r
994 break;\r
995 case TS_LECHO:\r
996 if (telnet->opt_states[o_echo.index] == ACTIVE) {\r
997 telnet->opt_states[o_echo.index] = REQUESTED;\r
998 send_opt(telnet, o_echo.nsend, o_echo.option);\r
999 }\r
1000 break;\r
1001 case TS_PING:\r
1002 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {\r
1003 b[1] = NOP;\r
1004 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);\r
1005 }\r
1006 break;\r
1007 default:\r
1008 break; /* never heard of it */\r
1009 }\r
1010 }\r
1011 \r
1012 static const struct telnet_special *telnet_get_specials(void *handle)\r
1013 {\r
1014 static const struct telnet_special specials[] = {\r
1015 {"Are You There", TS_AYT},\r
1016 {"Break", TS_BRK},\r
1017 {"Synch", TS_SYNCH},\r
1018 {"Erase Character", TS_EC},\r
1019 {"Erase Line", TS_EL},\r
1020 {"Go Ahead", TS_GA},\r
1021 {"No Operation", TS_NOP},\r
1022 {NULL, TS_SEP},\r
1023 {"Abort Process", TS_ABORT},\r
1024 {"Abort Output", TS_AO},\r
1025 {"Interrupt Process", TS_IP},\r
1026 {"Suspend Process", TS_SUSP},\r
1027 {NULL, TS_SEP},\r
1028 {"End Of Record", TS_EOR},\r
1029 {"End Of File", TS_EOF},\r
1030 {NULL, TS_EXITMENU}\r
1031 };\r
1032 return specials;\r
1033 }\r
1034 \r
1035 static int telnet_connected(void *handle)\r
1036 {\r
1037 Telnet telnet = (Telnet) handle;\r
1038 return telnet->s != NULL;\r
1039 }\r
1040 \r
1041 static int telnet_sendok(void *handle)\r
1042 {\r
1043 /* Telnet telnet = (Telnet) handle; */\r
1044 return 1;\r
1045 }\r
1046 \r
1047 static void telnet_unthrottle(void *handle, int backlog)\r
1048 {\r
1049 Telnet telnet = (Telnet) handle;\r
1050 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);\r
1051 }\r
1052 \r
1053 static int telnet_ldisc(void *handle, int option)\r
1054 {\r
1055 Telnet telnet = (Telnet) handle;\r
1056 if (option == LD_ECHO)\r
1057 return telnet->echoing;\r
1058 if (option == LD_EDIT)\r
1059 return telnet->editing;\r
1060 return FALSE;\r
1061 }\r
1062 \r
1063 static void telnet_provide_ldisc(void *handle, void *ldisc)\r
1064 {\r
1065 Telnet telnet = (Telnet) handle;\r
1066 telnet->ldisc = ldisc;\r
1067 }\r
1068 \r
1069 static void telnet_provide_logctx(void *handle, void *logctx)\r
1070 {\r
1071 /* This is a stub. */\r
1072 }\r
1073 \r
1074 static int telnet_exitcode(void *handle)\r
1075 {\r
1076 Telnet telnet = (Telnet) handle;\r
1077 if (telnet->s != NULL)\r
1078 return -1; /* still connected */\r
1079 else\r
1080 /* Telnet doesn't transmit exit codes back to the client */\r
1081 return 0;\r
1082 }\r
1083 \r
1084 /*\r
1085 * cfg_info for Telnet does nothing at all.\r
1086 */\r
1087 static int telnet_cfg_info(void *handle)\r
1088 {\r
1089 return 0;\r
1090 }\r
1091 \r
1092 Backend telnet_backend = {\r
1093 telnet_init,\r
1094 telnet_free,\r
1095 telnet_reconfig,\r
1096 telnet_send,\r
1097 telnet_sendbuffer,\r
1098 telnet_size,\r
1099 telnet_special,\r
1100 telnet_get_specials,\r
1101 telnet_connected,\r
1102 telnet_exitcode,\r
1103 telnet_sendok,\r
1104 telnet_ldisc,\r
1105 telnet_provide_ldisc,\r
1106 telnet_provide_logctx,\r
1107 telnet_unthrottle,\r
1108 telnet_cfg_info,\r
1109 23\r
1110 };\r