source: MondoRescue/branches/3.2/mindi-busybox/networking/telnet.c@ 3322

Last change on this file since 3322 was 3232, checked in by Bruno Cornec, 12 years ago
  • Update mindi-busybox to 1.21.1
File size: 13.1 KB
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1/* vi: set sw=4 ts=4: */
2/*
3 * telnet implementation for busybox
4 *
5 * Author: Tomi Ollila <too@iki.fi>
6 * Copyright (C) 1994-2000 by Tomi Ollila
7 *
8 * Created: Thu Apr 7 13:29:41 1994 too
9 * Last modified: Fri Jun 9 14:34:24 2000 too
10 *
11 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
12 *
13 * HISTORY
14 * Revision 3.1 1994/04/17 11:31:54 too
15 * initial revision
16 * Modified 2000/06/13 for inclusion into BusyBox by Erik Andersen <andersen@codepoet.org>
17 * Modified 2001/05/07 to add ability to pass TTYPE to remote host by Jim McQuillan
18 * <jam@ltsp.org>
19 * Modified 2004/02/11 to add ability to pass the USER variable to remote host
20 * by Fernando Silveira <swrh@gmx.net>
21 *
22 */
23
24//usage:#if ENABLE_FEATURE_TELNET_AUTOLOGIN
25//usage:#define telnet_trivial_usage
26//usage: "[-a] [-l USER] HOST [PORT]"
27//usage:#define telnet_full_usage "\n\n"
28//usage: "Connect to telnet server\n"
29//usage: "\n -a Automatic login with $USER variable"
30//usage: "\n -l USER Automatic login as USER"
31//usage:
32//usage:#else
33//usage:#define telnet_trivial_usage
34//usage: "HOST [PORT]"
35//usage:#define telnet_full_usage "\n\n"
36//usage: "Connect to telnet server"
37//usage:#endif
38
39#include <arpa/telnet.h>
40#include <netinet/in.h>
41#include "libbb.h"
42
43#ifdef __BIONIC__
44/* should be in arpa/telnet.h */
45# define IAC 255 /* interpret as command: */
46# define DONT 254 /* you are not to use option */
47# define DO 253 /* please, you use option */
48# define WONT 252 /* I won't use option */
49# define WILL 251 /* I will use option */
50# define SB 250 /* interpret as subnegotiation */
51# define SE 240 /* end sub negotiation */
52# define TELOPT_ECHO 1 /* echo */
53# define TELOPT_SGA 3 /* suppress go ahead */
54# define TELOPT_TTYPE 24 /* terminal type */
55# define TELOPT_NAWS 31 /* window size */
56#endif
57
58#ifdef DOTRACE
59# define TRACE(x, y) do { if (x) printf y; } while (0)
60#else
61# define TRACE(x, y)
62#endif
63
64enum {
65 DATABUFSIZE = 128,
66 IACBUFSIZE = 128,
67
68 CHM_TRY = 0,
69 CHM_ON = 1,
70 CHM_OFF = 2,
71
72 UF_ECHO = 0x01,
73 UF_SGA = 0x02,
74
75 TS_NORMAL = 0,
76 TS_COPY = 1,
77 TS_IAC = 2,
78 TS_OPT = 3,
79 TS_SUB1 = 4,
80 TS_SUB2 = 5,
81 TS_CR = 6,
82};
83
84typedef unsigned char byte;
85
86enum { netfd = 3 };
87
88struct globals {
89 int iaclen; /* could even use byte, but it's a loss on x86 */
90 byte telstate; /* telnet negotiation state from network input */
91 byte telwish; /* DO, DONT, WILL, WONT */
92 byte charmode;
93 byte telflags;
94 byte do_termios;
95#if ENABLE_FEATURE_TELNET_TTYPE
96 char *ttype;
97#endif
98#if ENABLE_FEATURE_TELNET_AUTOLOGIN
99 const char *autologin;
100#endif
101#if ENABLE_FEATURE_AUTOWIDTH
102 unsigned win_width, win_height;
103#endif
104 /* same buffer used both for network and console read/write */
105 char buf[DATABUFSIZE];
106 /* buffer to handle telnet negotiations */
107 char iacbuf[IACBUFSIZE];
108 struct termios termios_def;
109 struct termios termios_raw;
110} FIX_ALIASING;
111#define G (*(struct globals*)&bb_common_bufsiz1)
112#define INIT_G() do { \
113 struct G_sizecheck { \
114 char G_sizecheck[sizeof(G) > COMMON_BUFSIZE ? -1 : 1]; \
115 }; \
116} while (0)
117
118
119static void rawmode(void);
120static void cookmode(void);
121static void do_linemode(void);
122static void will_charmode(void);
123static void telopt(byte c);
124static void subneg(byte c);
125
126static void iac_flush(void)
127{
128 write(netfd, G.iacbuf, G.iaclen);
129 G.iaclen = 0;
130}
131
132#define write_str(fd, str) write(fd, str, sizeof(str) - 1)
133
134static void doexit(int ev) NORETURN;
135static void doexit(int ev)
136{
137 cookmode();
138 exit(ev);
139}
140
141static void con_escape(void)
142{
143 char b;
144
145 if (bb_got_signal) /* came from line mode... go raw */
146 rawmode();
147
148 write_str(1, "\r\nConsole escape. Commands are:\r\n\n"
149 " l go to line mode\r\n"
150 " c go to character mode\r\n"
151 " z suspend telnet\r\n"
152 " e exit telnet\r\n");
153
154 if (read(STDIN_FILENO, &b, 1) <= 0)
155 doexit(EXIT_FAILURE);
156
157 switch (b) {
158 case 'l':
159 if (!bb_got_signal) {
160 do_linemode();
161 goto ret;
162 }
163 break;
164 case 'c':
165 if (bb_got_signal) {
166 will_charmode();
167 goto ret;
168 }
169 break;
170 case 'z':
171 cookmode();
172 kill(0, SIGTSTP);
173 rawmode();
174 break;
175 case 'e':
176 doexit(EXIT_SUCCESS);
177 }
178
179 write_str(1, "continuing...\r\n");
180
181 if (bb_got_signal)
182 cookmode();
183 ret:
184 bb_got_signal = 0;
185}
186
187static void handle_net_output(int len)
188{
189 byte outbuf[2 * DATABUFSIZE];
190 byte *dst = outbuf;
191 byte *src = (byte*)G.buf;
192 byte *end = src + len;
193
194 while (src < end) {
195 byte c = *src++;
196 if (c == 0x1d) {
197 con_escape();
198 return;
199 }
200 *dst = c;
201 if (c == IAC)
202 *++dst = c; /* IAC -> IAC IAC */
203 else
204 if (c == '\r' || c == '\n') {
205 /* Enter key sends '\r' in raw mode and '\n' in cooked one.
206 *
207 * See RFC 1123 3.3.1 Telnet End-of-Line Convention.
208 * Using CR LF instead of other allowed possibilities
209 * like CR NUL - easier to talk to HTTP/SMTP servers.
210 */
211 *dst = '\r'; /* Enter -> CR LF */
212 *++dst = '\n';
213 }
214 dst++;
215 }
216 if (dst - outbuf != 0)
217 full_write(netfd, outbuf, dst - outbuf);
218}
219
220static void handle_net_input(int len)
221{
222 int i;
223 int cstart = 0;
224
225 for (i = 0; i < len; i++) {
226 byte c = G.buf[i];
227
228 if (G.telstate == TS_NORMAL) { /* most typical state */
229 if (c == IAC) {
230 cstart = i;
231 G.telstate = TS_IAC;
232 }
233 else if (c == '\r') {
234 cstart = i + 1;
235 G.telstate = TS_CR;
236 }
237 /* No IACs were seen so far, no need to copy
238 * bytes within G.buf: */
239 continue;
240 }
241
242 switch (G.telstate) {
243 case TS_CR:
244 /* Prev char was CR. If cur one is NUL, ignore it.
245 * See RFC 1123 section 3.3.1 for discussion of telnet EOL handling.
246 */
247 G.telstate = TS_COPY;
248 if (c == '\0')
249 break;
250 /* else: fall through - need to handle CR IAC ... properly */
251
252 case TS_COPY: /* Prev char was ordinary */
253 /* Similar to NORMAL, but in TS_COPY we need to copy bytes */
254 if (c == IAC)
255 G.telstate = TS_IAC;
256 else
257 G.buf[cstart++] = c;
258 if (c == '\r')
259 G.telstate = TS_CR;
260 break;
261
262 case TS_IAC: /* Prev char was IAC */
263 if (c == IAC) { /* IAC IAC -> one IAC */
264 G.buf[cstart++] = c;
265 G.telstate = TS_COPY;
266 break;
267 }
268 /* else */
269 switch (c) {
270 case SB:
271 G.telstate = TS_SUB1;
272 break;
273 case DO:
274 case DONT:
275 case WILL:
276 case WONT:
277 G.telwish = c;
278 G.telstate = TS_OPT;
279 break;
280 /* DATA MARK must be added later */
281 default:
282 G.telstate = TS_COPY;
283 }
284 break;
285
286 case TS_OPT: /* Prev chars were IAC WILL/WONT/DO/DONT */
287 telopt(c);
288 G.telstate = TS_COPY;
289 break;
290
291 case TS_SUB1: /* Subnegotiation */
292 case TS_SUB2: /* Subnegotiation */
293 subneg(c); /* can change G.telstate */
294 break;
295 }
296 }
297
298 if (G.telstate != TS_NORMAL) {
299 /* We had some IACs, or CR */
300 if (G.iaclen)
301 iac_flush();
302 if (G.telstate == TS_COPY) /* we aren't in the middle of IAC */
303 G.telstate = TS_NORMAL;
304 len = cstart;
305 }
306
307 if (len)
308 full_write(STDOUT_FILENO, G.buf, len);
309}
310
311static void put_iac(int c)
312{
313 G.iacbuf[G.iaclen++] = c;
314}
315
316static void put_iac2(byte wwdd, byte c)
317{
318 if (G.iaclen + 3 > IACBUFSIZE)
319 iac_flush();
320
321 put_iac(IAC);
322 put_iac(wwdd);
323 put_iac(c);
324}
325
326#if ENABLE_FEATURE_TELNET_TTYPE
327static void put_iac_subopt(byte c, char *str)
328{
329 int len = strlen(str) + 6; // ( 2 + 1 + 1 + strlen + 2 )
330
331 if (G.iaclen + len > IACBUFSIZE)
332 iac_flush();
333
334 put_iac(IAC);
335 put_iac(SB);
336 put_iac(c);
337 put_iac(0);
338
339 while (*str)
340 put_iac(*str++);
341
342 put_iac(IAC);
343 put_iac(SE);
344}
345#endif
346
347#if ENABLE_FEATURE_TELNET_AUTOLOGIN
348static void put_iac_subopt_autologin(void)
349{
350 int len = strlen(G.autologin) + 6; // (2 + 1 + 1 + strlen + 2)
351 const char *p = "USER";
352
353 if (G.iaclen + len > IACBUFSIZE)
354 iac_flush();
355
356 put_iac(IAC);
357 put_iac(SB);
358 put_iac(TELOPT_NEW_ENVIRON);
359 put_iac(TELQUAL_IS);
360 put_iac(NEW_ENV_VAR);
361
362 while (*p)
363 put_iac(*p++);
364
365 put_iac(NEW_ENV_VALUE);
366
367 p = G.autologin;
368 while (*p)
369 put_iac(*p++);
370
371 put_iac(IAC);
372 put_iac(SE);
373}
374#endif
375
376#if ENABLE_FEATURE_AUTOWIDTH
377static void put_iac_naws(byte c, int x, int y)
378{
379 if (G.iaclen + 9 > IACBUFSIZE)
380 iac_flush();
381
382 put_iac(IAC);
383 put_iac(SB);
384 put_iac(c);
385
386 put_iac((x >> 8) & 0xff);
387 put_iac(x & 0xff);
388 put_iac((y >> 8) & 0xff);
389 put_iac(y & 0xff);
390
391 put_iac(IAC);
392 put_iac(SE);
393}
394#endif
395
396static void setConMode(void)
397{
398 if (G.telflags & UF_ECHO) {
399 if (G.charmode == CHM_TRY) {
400 G.charmode = CHM_ON;
401 printf("\r\nEntering %s mode"
402 "\r\nEscape character is '^%c'.\r\n", "character", ']');
403 rawmode();
404 }
405 } else {
406 if (G.charmode != CHM_OFF) {
407 G.charmode = CHM_OFF;
408 printf("\r\nEntering %s mode"
409 "\r\nEscape character is '^%c'.\r\n", "line", 'C');
410 cookmode();
411 }
412 }
413}
414
415static void will_charmode(void)
416{
417 G.charmode = CHM_TRY;
418 G.telflags |= (UF_ECHO | UF_SGA);
419 setConMode();
420
421 put_iac2(DO, TELOPT_ECHO);
422 put_iac2(DO, TELOPT_SGA);
423 iac_flush();
424}
425
426static void do_linemode(void)
427{
428 G.charmode = CHM_TRY;
429 G.telflags &= ~(UF_ECHO | UF_SGA);
430 setConMode();
431
432 put_iac2(DONT, TELOPT_ECHO);
433 put_iac2(DONT, TELOPT_SGA);
434 iac_flush();
435}
436
437static void to_notsup(char c)
438{
439 if (G.telwish == WILL)
440 put_iac2(DONT, c);
441 else if (G.telwish == DO)
442 put_iac2(WONT, c);
443}
444
445static void to_echo(void)
446{
447 /* if server requests ECHO, don't agree */
448 if (G.telwish == DO) {
449 put_iac2(WONT, TELOPT_ECHO);
450 return;
451 }
452 if (G.telwish == DONT)
453 return;
454
455 if (G.telflags & UF_ECHO) {
456 if (G.telwish == WILL)
457 return;
458 } else if (G.telwish == WONT)
459 return;
460
461 if (G.charmode != CHM_OFF)
462 G.telflags ^= UF_ECHO;
463
464 if (G.telflags & UF_ECHO)
465 put_iac2(DO, TELOPT_ECHO);
466 else
467 put_iac2(DONT, TELOPT_ECHO);
468
469 setConMode();
470 full_write1_str("\r\n"); /* sudden modec */
471}
472
473static void to_sga(void)
474{
475 /* daemon always sends will/wont, client do/dont */
476
477 if (G.telflags & UF_SGA) {
478 if (G.telwish == WILL)
479 return;
480 } else if (G.telwish == WONT)
481 return;
482
483 G.telflags ^= UF_SGA; /* toggle */
484 if (G.telflags & UF_SGA)
485 put_iac2(DO, TELOPT_SGA);
486 else
487 put_iac2(DONT, TELOPT_SGA);
488}
489
490#if ENABLE_FEATURE_TELNET_TTYPE
491static void to_ttype(void)
492{
493 /* Tell server we will (or won't) do TTYPE */
494 if (G.ttype)
495 put_iac2(WILL, TELOPT_TTYPE);
496 else
497 put_iac2(WONT, TELOPT_TTYPE);
498}
499#endif
500
501#if ENABLE_FEATURE_TELNET_AUTOLOGIN
502static void to_new_environ(void)
503{
504 /* Tell server we will (or will not) do AUTOLOGIN */
505 if (G.autologin)
506 put_iac2(WILL, TELOPT_NEW_ENVIRON);
507 else
508 put_iac2(WONT, TELOPT_NEW_ENVIRON);
509}
510#endif
511
512#if ENABLE_FEATURE_AUTOWIDTH
513static void to_naws(void)
514{
515 /* Tell server we will do NAWS */
516 put_iac2(WILL, TELOPT_NAWS);
517}
518#endif
519
520static void telopt(byte c)
521{
522 switch (c) {
523 case TELOPT_ECHO:
524 to_echo(); break;
525 case TELOPT_SGA:
526 to_sga(); break;
527#if ENABLE_FEATURE_TELNET_TTYPE
528 case TELOPT_TTYPE:
529 to_ttype(); break;
530#endif
531#if ENABLE_FEATURE_TELNET_AUTOLOGIN
532 case TELOPT_NEW_ENVIRON:
533 to_new_environ(); break;
534#endif
535#if ENABLE_FEATURE_AUTOWIDTH
536 case TELOPT_NAWS:
537 to_naws();
538 put_iac_naws(c, G.win_width, G.win_height);
539 break;
540#endif
541 default:
542 to_notsup(c);
543 break;
544 }
545}
546
547/* subnegotiation -- ignore all (except TTYPE,NAWS) */
548static void subneg(byte c)
549{
550 switch (G.telstate) {
551 case TS_SUB1:
552 if (c == IAC)
553 G.telstate = TS_SUB2;
554#if ENABLE_FEATURE_TELNET_TTYPE
555 else
556 if (c == TELOPT_TTYPE && G.ttype)
557 put_iac_subopt(TELOPT_TTYPE, G.ttype);
558#endif
559#if ENABLE_FEATURE_TELNET_AUTOLOGIN
560 else
561 if (c == TELOPT_NEW_ENVIRON && G.autologin)
562 put_iac_subopt_autologin();
563#endif
564 break;
565 case TS_SUB2:
566 if (c == SE) {
567 G.telstate = TS_COPY;
568 return;
569 }
570 G.telstate = TS_SUB1;
571 break;
572 }
573}
574
575static void rawmode(void)
576{
577 if (G.do_termios)
578 tcsetattr(0, TCSADRAIN, &G.termios_raw);
579}
580
581static void cookmode(void)
582{
583 if (G.do_termios)
584 tcsetattr(0, TCSADRAIN, &G.termios_def);
585}
586
587int telnet_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
588int telnet_main(int argc UNUSED_PARAM, char **argv)
589{
590 char *host;
591 int port;
592 int len;
593 struct pollfd ufds[2];
594
595 INIT_G();
596
597#if ENABLE_FEATURE_AUTOWIDTH
598 get_terminal_width_height(0, &G.win_width, &G.win_height);
599#endif
600
601#if ENABLE_FEATURE_TELNET_TTYPE
602 G.ttype = getenv("TERM");
603#endif
604
605 if (tcgetattr(0, &G.termios_def) >= 0) {
606 G.do_termios = 1;
607 G.termios_raw = G.termios_def;
608 cfmakeraw(&G.termios_raw);
609 }
610
611#if ENABLE_FEATURE_TELNET_AUTOLOGIN
612 if (1 & getopt32(argv, "al:", &G.autologin))
613 G.autologin = getenv("USER");
614 argv += optind;
615#else
616 argv++;
617#endif
618 if (!*argv)
619 bb_show_usage();
620 host = *argv++;
621 port = bb_lookup_port(*argv ? *argv++ : "telnet", "tcp", 23);
622 if (*argv) /* extra params?? */
623 bb_show_usage();
624
625 xmove_fd(create_and_connect_stream_or_die(host, port), netfd);
626
627 setsockopt(netfd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
628
629 signal(SIGINT, record_signo);
630
631 ufds[0].fd = STDIN_FILENO;
632 ufds[0].events = POLLIN;
633 ufds[1].fd = netfd;
634 ufds[1].events = POLLIN;
635
636 while (1) {
637 if (poll(ufds, 2, -1) < 0) {
638 /* error, ignore and/or log something, bay go to loop */
639 if (bb_got_signal)
640 con_escape();
641 else
642 sleep(1);
643 continue;
644 }
645
646// FIXME: reads can block. Need full bidirectional buffering.
647
648 if (ufds[0].revents) {
649 len = safe_read(STDIN_FILENO, G.buf, DATABUFSIZE);
650 if (len <= 0)
651 doexit(EXIT_SUCCESS);
652 TRACE(0, ("Read con: %d\n", len));
653 handle_net_output(len);
654 }
655
656 if (ufds[1].revents) {
657 len = safe_read(netfd, G.buf, DATABUFSIZE);
658 if (len <= 0) {
659 full_write1_str("Connection closed by foreign host\r\n");
660 doexit(EXIT_FAILURE);
661 }
662 TRACE(0, ("Read netfd (%d): %d\n", netfd, len));
663 handle_net_input(len);
664 }
665 } /* while (1) */
666}
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