source: MondoRescue/branches/2.2.9/mindi-busybox/networking/telnet.c@ 3320

Last change on this file since 3320 was 3320, checked in by Bruno Cornec, 9 years ago
  • Re-add (thanks git BTW) the 2.2.9 branch which had been destroyed in the move to 3.0
  • Property svn:eol-style set to native
File size: 12.4 KB
Line 
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#include <arpa/telnet.h>
25#include <netinet/in.h>
26#include "libbb.h"
27
28#ifdef DOTRACE
29#define TRACE(x, y) do { if (x) printf y; } while (0)
30#else
31#define TRACE(x, y)
32#endif
33
34enum {
35 DATABUFSIZE = 128,
36 IACBUFSIZE = 128,
37
38 CHM_TRY = 0,
39 CHM_ON = 1,
40 CHM_OFF = 2,
41
42 UF_ECHO = 0x01,
43 UF_SGA = 0x02,
44
45 TS_NORMAL = 0,
46 TS_COPY = 1,
47 TS_IAC = 2,
48 TS_OPT = 3,
49 TS_SUB1 = 4,
50 TS_SUB2 = 5,
51 TS_CR = 6,
52};
53
54typedef unsigned char byte;
55
56enum { netfd = 3 };
57
58struct globals {
59 int iaclen; /* could even use byte, but it's a loss on x86 */
60 byte telstate; /* telnet negotiation state from network input */
61 byte telwish; /* DO, DONT, WILL, WONT */
62 byte charmode;
63 byte telflags;
64 byte do_termios;
65#if ENABLE_FEATURE_TELNET_TTYPE
66 char *ttype;
67#endif
68#if ENABLE_FEATURE_TELNET_AUTOLOGIN
69 const char *autologin;
70#endif
71#if ENABLE_FEATURE_AUTOWIDTH
72 unsigned win_width, win_height;
73#endif
74 /* same buffer used both for network and console read/write */
75 char buf[DATABUFSIZE];
76 /* buffer to handle telnet negotiations */
77 char iacbuf[IACBUFSIZE];
78 struct termios termios_def;
79 struct termios termios_raw;
80} FIX_ALIASING;
81#define G (*(struct globals*)&bb_common_bufsiz1)
82#define INIT_G() do { \
83 struct G_sizecheck { \
84 char G_sizecheck[sizeof(G) > COMMON_BUFSIZE ? -1 : 1]; \
85 }; \
86} while (0)
87
88
89static void rawmode(void);
90static void cookmode(void);
91static void do_linemode(void);
92static void will_charmode(void);
93static void telopt(byte c);
94static void subneg(byte c);
95
96static void iac_flush(void)
97{
98 write(netfd, G.iacbuf, G.iaclen);
99 G.iaclen = 0;
100}
101
102#define write_str(fd, str) write(fd, str, sizeof(str) - 1)
103
104static void doexit(int ev) NORETURN;
105static void doexit(int ev)
106{
107 cookmode();
108 exit(ev);
109}
110
111static void con_escape(void)
112{
113 char b;
114
115 if (bb_got_signal) /* came from line mode... go raw */
116 rawmode();
117
118 write_str(1, "\r\nConsole escape. Commands are:\r\n\n"
119 " l go to line mode\r\n"
120 " c go to character mode\r\n"
121 " z suspend telnet\r\n"
122 " e exit telnet\r\n");
123
124 if (read(STDIN_FILENO, &b, 1) <= 0)
125 doexit(EXIT_FAILURE);
126
127 switch (b) {
128 case 'l':
129 if (!bb_got_signal) {
130 do_linemode();
131 goto ret;
132 }
133 break;
134 case 'c':
135 if (bb_got_signal) {
136 will_charmode();
137 goto ret;
138 }
139 break;
140 case 'z':
141 cookmode();
142 kill(0, SIGTSTP);
143 rawmode();
144 break;
145 case 'e':
146 doexit(EXIT_SUCCESS);
147 }
148
149 write_str(1, "continuing...\r\n");
150
151 if (bb_got_signal)
152 cookmode();
153 ret:
154 bb_got_signal = 0;
155}
156
157static void handle_net_output(int len)
158{
159 /* here we could do smart tricks how to handle 0xFF:s in output
160 * stream like writing twice every sequence of FF:s (thus doing
161 * many write()s. But I think interactive telnet application does
162 * not need to be 100% 8-bit clean, so changing every 0xff:s to
163 * 0x7f:s
164 *
165 * 2002-mar-21, Przemyslaw Czerpak (druzus@polbox.com)
166 * I don't agree.
167 * first - I cannot use programs like sz/rz
168 * second - the 0x0D is sent as one character and if the next
169 * char is 0x0A then it's eaten by a server side.
170 * third - why do you have to make 'many write()s'?
171 * I don't understand.
172 * So I implemented it. It's really useful for me. I hope that
173 * other people will find it interesting too.
174 */
175 byte outbuf[2 * DATABUFSIZE];
176 byte *p = (byte*)G.buf;
177 int j = 0;
178
179 for (; len > 0; len--, p++) {
180 byte c = *p;
181 if (c == 0x1d) {
182 con_escape();
183 return;
184 }
185 outbuf[j++] = c;
186 if (c == IAC)
187 outbuf[j++] = c; /* IAC -> IAC IAC */
188 else if (c == '\r')
189 outbuf[j++] = '\0'; /* CR -> CR NUL */
190 }
191 if (j > 0)
192 full_write(netfd, outbuf, j);
193}
194
195static void handle_net_input(int len)
196{
197 int i;
198 int cstart = 0;
199
200 for (i = 0; i < len; i++) {
201 byte c = G.buf[i];
202
203 if (G.telstate == TS_NORMAL) { /* most typical state */
204 if (c == IAC) {
205 cstart = i;
206 G.telstate = TS_IAC;
207 }
208 else if (c == '\r') {
209 cstart = i + 1;
210 G.telstate = TS_CR;
211 }
212 /* No IACs were seen so far, no need to copy
213 * bytes within G.buf: */
214 continue;
215 }
216
217 switch (G.telstate) {
218 case TS_CR:
219 /* Prev char was CR. If cur one is NUL, ignore it.
220 * See RFC 1123 section 3.3.1 for discussion of telnet EOL handling.
221 */
222 G.telstate = TS_COPY;
223 if (c == '\0')
224 break;
225 /* else: fall through - need to handle CR IAC ... properly */
226
227 case TS_COPY: /* Prev char was ordinary */
228 /* Similar to NORMAL, but in TS_COPY we need to copy bytes */
229 if (c == IAC)
230 G.telstate = TS_IAC;
231 else
232 G.buf[cstart++] = c;
233 if (c == '\r')
234 G.telstate = TS_CR;
235 break;
236
237 case TS_IAC: /* Prev char was IAC */
238 if (c == IAC) { /* IAC IAC -> one IAC */
239 G.buf[cstart++] = c;
240 G.telstate = TS_COPY;
241 break;
242 }
243 /* else */
244 switch (c) {
245 case SB:
246 G.telstate = TS_SUB1;
247 break;
248 case DO:
249 case DONT:
250 case WILL:
251 case WONT:
252 G.telwish = c;
253 G.telstate = TS_OPT;
254 break;
255 /* DATA MARK must be added later */
256 default:
257 G.telstate = TS_COPY;
258 }
259 break;
260
261 case TS_OPT: /* Prev chars were IAC WILL/WONT/DO/DONT */
262 telopt(c);
263 G.telstate = TS_COPY;
264 break;
265
266 case TS_SUB1: /* Subnegotiation */
267 case TS_SUB2: /* Subnegotiation */
268 subneg(c); /* can change G.telstate */
269 break;
270 }
271 }
272
273 if (G.telstate != TS_NORMAL) {
274 /* We had some IACs, or CR */
275 if (G.iaclen)
276 iac_flush();
277 if (G.telstate == TS_COPY) /* we aren't in the middle of IAC */
278 G.telstate = TS_NORMAL;
279 len = cstart;
280 }
281
282 if (len)
283 full_write(STDOUT_FILENO, G.buf, len);
284}
285
286static void put_iac(int c)
287{
288 G.iacbuf[G.iaclen++] = c;
289}
290
291static void put_iac2(byte wwdd, byte c)
292{
293 if (G.iaclen + 3 > IACBUFSIZE)
294 iac_flush();
295
296 put_iac(IAC);
297 put_iac(wwdd);
298 put_iac(c);
299}
300
301#if ENABLE_FEATURE_TELNET_TTYPE
302static void put_iac_subopt(byte c, char *str)
303{
304 int len = strlen(str) + 6; // ( 2 + 1 + 1 + strlen + 2 )
305
306 if (G.iaclen + len > IACBUFSIZE)
307 iac_flush();
308
309 put_iac(IAC);
310 put_iac(SB);
311 put_iac(c);
312 put_iac(0);
313
314 while (*str)
315 put_iac(*str++);
316
317 put_iac(IAC);
318 put_iac(SE);
319}
320#endif
321
322#if ENABLE_FEATURE_TELNET_AUTOLOGIN
323static void put_iac_subopt_autologin(void)
324{
325 int len = strlen(G.autologin) + 6; // (2 + 1 + 1 + strlen + 2)
326 const char *p = "USER";
327
328 if (G.iaclen + len > IACBUFSIZE)
329 iac_flush();
330
331 put_iac(IAC);
332 put_iac(SB);
333 put_iac(TELOPT_NEW_ENVIRON);
334 put_iac(TELQUAL_IS);
335 put_iac(NEW_ENV_VAR);
336
337 while (*p)
338 put_iac(*p++);
339
340 put_iac(NEW_ENV_VALUE);
341
342 p = G.autologin;
343 while (*p)
344 put_iac(*p++);
345
346 put_iac(IAC);
347 put_iac(SE);
348}
349#endif
350
351#if ENABLE_FEATURE_AUTOWIDTH
352static void put_iac_naws(byte c, int x, int y)
353{
354 if (G.iaclen + 9 > IACBUFSIZE)
355 iac_flush();
356
357 put_iac(IAC);
358 put_iac(SB);
359 put_iac(c);
360
361 put_iac((x >> 8) & 0xff);
362 put_iac(x & 0xff);
363 put_iac((y >> 8) & 0xff);
364 put_iac(y & 0xff);
365
366 put_iac(IAC);
367 put_iac(SE);
368}
369#endif
370
371static char const escapecharis[] ALIGN1 = "\r\nEscape character is ";
372
373static void setConMode(void)
374{
375 if (G.telflags & UF_ECHO) {
376 if (G.charmode == CHM_TRY) {
377 G.charmode = CHM_ON;
378 printf("\r\nEntering character mode%s'^]'.\r\n", escapecharis);
379 rawmode();
380 }
381 } else {
382 if (G.charmode != CHM_OFF) {
383 G.charmode = CHM_OFF;
384 printf("\r\nEntering line mode%s'^C'.\r\n", escapecharis);
385 cookmode();
386 }
387 }
388}
389
390static void will_charmode(void)
391{
392 G.charmode = CHM_TRY;
393 G.telflags |= (UF_ECHO | UF_SGA);
394 setConMode();
395
396 put_iac2(DO, TELOPT_ECHO);
397 put_iac2(DO, TELOPT_SGA);
398 iac_flush();
399}
400
401static void do_linemode(void)
402{
403 G.charmode = CHM_TRY;
404 G.telflags &= ~(UF_ECHO | UF_SGA);
405 setConMode();
406
407 put_iac2(DONT, TELOPT_ECHO);
408 put_iac2(DONT, TELOPT_SGA);
409 iac_flush();
410}
411
412static void to_notsup(char c)
413{
414 if (G.telwish == WILL)
415 put_iac2(DONT, c);
416 else if (G.telwish == DO)
417 put_iac2(WONT, c);
418}
419
420static void to_echo(void)
421{
422 /* if server requests ECHO, don't agree */
423 if (G.telwish == DO) {
424 put_iac2(WONT, TELOPT_ECHO);
425 return;
426 }
427 if (G.telwish == DONT)
428 return;
429
430 if (G.telflags & UF_ECHO) {
431 if (G.telwish == WILL)
432 return;
433 } else if (G.telwish == WONT)
434 return;
435
436 if (G.charmode != CHM_OFF)
437 G.telflags ^= UF_ECHO;
438
439 if (G.telflags & UF_ECHO)
440 put_iac2(DO, TELOPT_ECHO);
441 else
442 put_iac2(DONT, TELOPT_ECHO);
443
444 setConMode();
445 full_write1_str("\r\n"); /* sudden modec */
446}
447
448static void to_sga(void)
449{
450 /* daemon always sends will/wont, client do/dont */
451
452 if (G.telflags & UF_SGA) {
453 if (G.telwish == WILL)
454 return;
455 } else if (G.telwish == WONT)
456 return;
457
458 G.telflags ^= UF_SGA; /* toggle */
459 if (G.telflags & UF_SGA)
460 put_iac2(DO, TELOPT_SGA);
461 else
462 put_iac2(DONT, TELOPT_SGA);
463}
464
465#if ENABLE_FEATURE_TELNET_TTYPE
466static void to_ttype(void)
467{
468 /* Tell server we will (or won't) do TTYPE */
469 if (G.ttype)
470 put_iac2(WILL, TELOPT_TTYPE);
471 else
472 put_iac2(WONT, TELOPT_TTYPE);
473}
474#endif
475
476#if ENABLE_FEATURE_TELNET_AUTOLOGIN
477static void to_new_environ(void)
478{
479 /* Tell server we will (or will not) do AUTOLOGIN */
480 if (G.autologin)
481 put_iac2(WILL, TELOPT_NEW_ENVIRON);
482 else
483 put_iac2(WONT, TELOPT_NEW_ENVIRON);
484}
485#endif
486
487#if ENABLE_FEATURE_AUTOWIDTH
488static void to_naws(void)
489{
490 /* Tell server we will do NAWS */
491 put_iac2(WILL, TELOPT_NAWS);
492}
493#endif
494
495static void telopt(byte c)
496{
497 switch (c) {
498 case TELOPT_ECHO:
499 to_echo(); break;
500 case TELOPT_SGA:
501 to_sga(); break;
502#if ENABLE_FEATURE_TELNET_TTYPE
503 case TELOPT_TTYPE:
504 to_ttype(); break;
505#endif
506#if ENABLE_FEATURE_TELNET_AUTOLOGIN
507 case TELOPT_NEW_ENVIRON:
508 to_new_environ(); break;
509#endif
510#if ENABLE_FEATURE_AUTOWIDTH
511 case TELOPT_NAWS:
512 to_naws();
513 put_iac_naws(c, G.win_width, G.win_height);
514 break;
515#endif
516 default:
517 to_notsup(c);
518 break;
519 }
520}
521
522/* subnegotiation -- ignore all (except TTYPE,NAWS) */
523static void subneg(byte c)
524{
525 switch (G.telstate) {
526 case TS_SUB1:
527 if (c == IAC)
528 G.telstate = TS_SUB2;
529#if ENABLE_FEATURE_TELNET_TTYPE
530 else
531 if (c == TELOPT_TTYPE && G.ttype)
532 put_iac_subopt(TELOPT_TTYPE, G.ttype);
533#endif
534#if ENABLE_FEATURE_TELNET_AUTOLOGIN
535 else
536 if (c == TELOPT_NEW_ENVIRON && G.autologin)
537 put_iac_subopt_autologin();
538#endif
539 break;
540 case TS_SUB2:
541 if (c == SE) {
542 G.telstate = TS_COPY;
543 return;
544 }
545 G.telstate = TS_SUB1;
546 break;
547 }
548}
549
550static void rawmode(void)
551{
552 if (G.do_termios)
553 tcsetattr(0, TCSADRAIN, &G.termios_raw);
554}
555
556static void cookmode(void)
557{
558 if (G.do_termios)
559 tcsetattr(0, TCSADRAIN, &G.termios_def);
560}
561
562int telnet_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
563int telnet_main(int argc UNUSED_PARAM, char **argv)
564{
565 char *host;
566 int port;
567 int len;
568 struct pollfd ufds[2];
569
570 INIT_G();
571
572#if ENABLE_FEATURE_AUTOWIDTH
573 get_terminal_width_height(0, &G.win_width, &G.win_height);
574#endif
575
576#if ENABLE_FEATURE_TELNET_TTYPE
577 G.ttype = getenv("TERM");
578#endif
579
580 if (tcgetattr(0, &G.termios_def) >= 0) {
581 G.do_termios = 1;
582 G.termios_raw = G.termios_def;
583 cfmakeraw(&G.termios_raw);
584 }
585
586#if ENABLE_FEATURE_TELNET_AUTOLOGIN
587 if (1 & getopt32(argv, "al:", &G.autologin))
588 G.autologin = getenv("USER");
589 argv += optind;
590#else
591 argv++;
592#endif
593 if (!*argv)
594 bb_show_usage();
595 host = *argv++;
596 port = bb_lookup_port(*argv ? *argv++ : "telnet", "tcp", 23);
597 if (*argv) /* extra params?? */
598 bb_show_usage();
599
600 xmove_fd(create_and_connect_stream_or_die(host, port), netfd);
601
602 setsockopt(netfd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
603
604 signal(SIGINT, record_signo);
605
606 ufds[0].fd = STDIN_FILENO;
607 ufds[0].events = POLLIN;
608 ufds[1].fd = netfd;
609 ufds[1].events = POLLIN;
610
611 while (1) {
612 if (poll(ufds, 2, -1) < 0) {
613 /* error, ignore and/or log something, bay go to loop */
614 if (bb_got_signal)
615 con_escape();
616 else
617 sleep(1);
618 continue;
619 }
620
621// FIXME: reads can block. Need full bidirectional buffering.
622
623 if (ufds[0].revents) {
624 len = safe_read(STDIN_FILENO, G.buf, DATABUFSIZE);
625 if (len <= 0)
626 doexit(EXIT_SUCCESS);
627 TRACE(0, ("Read con: %d\n", len));
628 handle_net_output(len);
629 }
630
631 if (ufds[1].revents) {
632 len = safe_read(netfd, G.buf, DATABUFSIZE);
633 if (len <= 0) {
634 full_write1_str("Connection closed by foreign host\r\n");
635 doexit(EXIT_FAILURE);
636 }
637 TRACE(0, ("Read netfd (%d): %d\n", netfd, len));
638 handle_net_input(len);
639 }
640 } /* while (1) */
641}
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