1 /* vi: set sw=4 ts=4: */
3 * telnet implementation for busybox
5 * Author: Tomi Ollila <too@iki.fi>
6 * Copyright (C) 1994-2000 by Tomi Ollila
8 * Created: Thu Apr 7 13:29:41 1994 too
9 * Last modified: Fri Jun 9 14:34:24 2000 too
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
26 * Revision 3.1 1994/04/17 11:31:54 too
28 * Modified 2000/06/13 for inclusion into BusyBox by Erik Andersen
29 * <andersen@lineo.com>
30 * Modified 2001/05/07 to add ability to pass TTYPE to remote host by Jim McQuillan
42 #include <arpa/telnet.h>
43 #include <sys/types.h>
44 #include <sys/socket.h>
45 #include <netinet/in.h>
49 #ifdef CONFIG_FEATURE_AUTOWIDTH
50 # include <sys/ioctl.h>
54 static const int DOTRACE = 1;
58 #include <arpa/inet.h> /* for inet_ntoa()... */
59 #define TRACE(x, y) do { if (x) printf y; } while (0)
71 #define DATABUFSIZE 128
72 #define IACBUFSIZE 128
74 static const int CHM_TRY = 0;
75 static const int CHM_ON = 1;
76 static const int CHM_OFF = 2;
78 static const int UF_ECHO = 0x01;
79 static const int UF_SGA = 0x02;
89 #define WriteCS(fd, str) write(fd, str, sizeof str -1)
91 typedef unsigned char byte;
93 /* use globals to reduce size ??? */ /* test this hypothesis later */
94 static struct Globalvars {
95 int netfd; /* console fd:s are 0 and 1 (and 2) */
96 /* same buffer used both for network and console read/write */
97 char buf[DATABUFSIZE]; /* allocating so static size is smaller */
98 byte telstate; /* telnet negotiation state from network input */
99 byte telwish; /* DO, DONT, WILL, WONT */
103 /* buffer to handle telnet negotiations */
104 char iacbuf[IACBUFSIZE];
105 short iaclen; /* could even use byte */
106 struct termios termios_def;
107 struct termios termios_raw;
110 #define xUSE_GLOBALVAR_PTR /* xUSE... -> don't use :D (makes smaller code) */
112 #ifdef USE_GLOBALVAR_PTR
113 struct Globalvars * Gptr;
116 static struct Globalvars G;
119 static inline void iacflush(void)
121 write(G.netfd, G.iacbuf, G.iaclen);
125 /* Function prototypes */
126 static int getport(char * p);
127 static struct in_addr getserver(char * p);
128 static void setup_sockaddr_in(struct sockaddr_in * addr, int port);
129 static int remote_connect(struct in_addr addr, int port);
130 static void rawmode(void);
131 static void cookmode(void);
132 static void do_linemode(void);
133 static void will_charmode(void);
134 static void telopt(byte c);
135 static int subneg(byte c);
137 static int local_bind(int port);
143 #ifdef CONFIG_FEATURE_TELNET_TTYPE
147 #ifdef CONFIG_FEATURE_AUTOWIDTH
148 static int win_width, win_height;
151 static void doexit(int ev)
157 static void conescape(void)
161 if (G.gotsig) /* came from line mode... go raw */
164 WriteCS(1, "\r\nConsole escape. Commands are:\r\n\n"
165 " l go to line mode\r\n"
166 " c go to character mode\r\n"
167 " z suspend telnet\r\n"
168 " e exit telnet\r\n");
170 if (read(0, &b, 1) <= 0)
198 WriteCS(1, "continuing...\r\n");
207 static void handlenetoutput(int len)
209 /* here we could do smart tricks how to handle 0xFF:s in output
210 * stream like writing twice every sequence of FF:s (thus doing
211 * many write()s. But I think interactive telnet application does
212 * not need to be 100% 8-bit clean, so changing every 0xff:s to
215 * 2002-mar-21, Przemyslaw Czerpak (druzus@polbox.com)
217 * first - I cannot use programs like sz/rz
218 * second - the 0x0D is sent as one character and if the next
219 * char is 0x0A then it's eaten by a server side.
220 * third - whay doy you have to make 'many write()s'?
221 * I don't understand.
222 * So I implemented it. It's realy useful for me. I hope that
223 * others people will find it interesting to.
228 byte outbuf[4*DATABUFSIZE];
230 for (i = len, j = 0; i > 0; i--, p++)
244 write(G.netfd, outbuf, j);
248 static void handlenetinput(int len)
253 for (i = 0; i < len; i++)
257 if (G.telstate == 0) /* most of the time state == 0 */
276 if (c == IAC) /* IAC IAC -> 0xFF */
286 G.telstate = TS_SUB1;
296 G.telstate = TS_0; /* DATA MARK must be added later */
299 case TS_OPT: /* WILL, WONT, DO, DONT */
303 case TS_SUB1: /* Subnegotiation */
304 case TS_SUB2: /* Subnegotiation */
312 if (G.iaclen) iacflush();
313 if (G.telstate == TS_0) G.telstate = 0;
319 write(1, G.buf, len);
323 /* ******************************* */
325 static inline void putiac(int c)
327 G.iacbuf[G.iaclen++] = c;
331 static void putiac2(byte wwdd, byte c)
333 if (G.iaclen + 3 > IACBUFSIZE)
342 static void putiac1(byte c)
344 if (G.iaclen + 2 > IACBUFSIZE)
352 #ifdef CONFIG_FEATURE_TELNET_TTYPE
353 static void putiac_subopt(byte c, char *str)
355 int len = strlen(str) + 6; // ( 2 + 1 + 1 + strlen + 2 )
357 if (G.iaclen + len > IACBUFSIZE)
373 #ifdef CONFIG_FEATURE_AUTOWIDTH
374 static void putiac_naws(byte c, int x, int y)
376 if (G.iaclen + 9 > IACBUFSIZE)
383 putiac((x >> 8) & 0xff);
385 putiac((y >> 8) & 0xff);
393 /* void putiacstring (subneg strings) */
395 /* ******************************* */
397 static char const escapecharis[] = "\r\nEscape character is ";
399 static void setConMode(void)
401 if (G.telflags & UF_ECHO)
403 if (G.charmode == CHM_TRY) {
405 printf("\r\nEntering character mode%s'^]'.\r\n", escapecharis);
411 if (G.charmode != CHM_OFF) {
412 G.charmode = CHM_OFF;
413 printf("\r\nEntering line mode%s'^C'.\r\n", escapecharis);
419 /* ******************************* */
421 static void will_charmode(void)
423 G.charmode = CHM_TRY;
424 G.telflags |= (UF_ECHO | UF_SGA);
427 putiac2(DO, TELOPT_ECHO);
428 putiac2(DO, TELOPT_SGA);
432 static void do_linemode(void)
434 G.charmode = CHM_TRY;
435 G.telflags &= ~(UF_ECHO | UF_SGA);
438 putiac2(DONT, TELOPT_ECHO);
439 putiac2(DONT, TELOPT_SGA);
443 /* ******************************* */
445 static inline void to_notsup(char c)
447 if (G.telwish == WILL) putiac2(DONT, c);
448 else if (G.telwish == DO) putiac2(WONT, c);
451 static inline void to_echo(void)
453 /* if server requests ECHO, don't agree */
454 if (G.telwish == DO) { putiac2(WONT, TELOPT_ECHO); return; }
455 else if (G.telwish == DONT) return;
457 if (G.telflags & UF_ECHO)
459 if (G.telwish == WILL)
463 if (G.telwish == WONT)
466 if (G.charmode != CHM_OFF)
467 G.telflags ^= UF_ECHO;
469 if (G.telflags & UF_ECHO)
470 putiac2(DO, TELOPT_ECHO);
472 putiac2(DONT, TELOPT_ECHO);
475 WriteCS(1, "\r\n"); /* sudden modec */
478 static inline void to_sga(void)
480 /* daemon always sends will/wont, client do/dont */
482 if (G.telflags & UF_SGA)
484 if (G.telwish == WILL)
488 if (G.telwish == WONT)
491 if ((G.telflags ^= UF_SGA) & UF_SGA) /* toggle */
492 putiac2(DO, TELOPT_SGA);
494 putiac2(DONT, TELOPT_SGA);
499 #ifdef CONFIG_FEATURE_TELNET_TTYPE
500 static inline void to_ttype(void)
502 /* Tell server we will (or won't) do TTYPE */
505 putiac2(WILL, TELOPT_TTYPE);
507 putiac2(WONT, TELOPT_TTYPE);
513 #ifdef CONFIG_FEATURE_AUTOWIDTH
514 static inline void to_naws(void)
516 /* Tell server we will do NAWS */
517 putiac2(WILL, TELOPT_NAWS);
522 static void telopt(byte c)
526 case TELOPT_ECHO: to_echo(c); break;
527 case TELOPT_SGA: to_sga(c); break;
528 #ifdef CONFIG_FEATURE_TELNET_TTYPE
529 case TELOPT_TTYPE: to_ttype(c);break;
531 #ifdef CONFIG_FEATURE_AUTOWIDTH
532 case TELOPT_NAWS: to_naws(c);
533 putiac_naws(c, win_width, win_height);
536 default: to_notsup(c);
542 /* ******************************* */
544 /* subnegotiation -- ignore all (except TTYPE,NAWS) */
546 static int subneg(byte c)
552 G.telstate = TS_SUB2;
553 #ifdef CONFIG_FEATURE_TELNET_TTYPE
555 if (c == TELOPT_TTYPE)
556 putiac_subopt(TELOPT_TTYPE,ttype);
562 G.telstate = TS_SUB1;
568 /* ******************************* */
570 static void fgotsig(int sig)
576 static void rawmode(void)
578 tcsetattr(0, TCSADRAIN, &G.termios_raw);
581 static void cookmode(void)
583 tcsetattr(0, TCSADRAIN, &G.termios_def);
586 extern int telnet_main(int argc, char** argv)
592 struct pollfd ufds[2];
598 #ifdef CONFIG_FEATURE_AUTOWIDTH
600 if( ioctl(0, TIOCGWINSZ, &winp) == 0 ) {
601 win_width = winp.ws_col;
602 win_height = winp.ws_row;
606 #ifdef CONFIG_FEATURE_TELNET_TTYPE
607 ttype = getenv("TERM");
610 memset(&G, 0, sizeof G);
612 if (tcgetattr(0, &G.termios_def) < 0)
615 G.termios_raw = G.termios_def;
616 cfmakeraw(&G.termios_raw);
618 if (argc < 2) show_usage();
619 port = (argc > 2)? getport(argv[2]): 23;
621 host = getserver(argv[1]);
623 G.netfd = remote_connect(host, port);
625 signal(SIGINT, fgotsig);
628 ufds[0].fd = 0; ufds[1].fd = G.netfd;
629 ufds[0].events = ufds[1].events = POLLIN;
633 FD_SET(G.netfd, &readfds);
640 fd_set rfds = readfds;
642 switch (select(maxfd, &rfds, NULL, NULL, NULL))
644 switch (poll(ufds, 2, -1))
650 /* error, ignore and/or log something, bay go to loop */
659 if (ufds[0].revents) /* well, should check POLLIN, but ... */
661 if (FD_ISSET(0, &rfds))
664 len = read(0, G.buf, DATABUFSIZE);
669 TRACE(0, ("Read con: %d\n", len));
671 handlenetoutput(len);
675 if (ufds[1].revents) /* well, should check POLLIN, but ... */
677 if (FD_ISSET(G.netfd, &rfds))
680 len = read(G.netfd, G.buf, DATABUFSIZE);
684 WriteCS(1, "Connection closed by foreign host.\r\n");
687 TRACE(0, ("Read netfd (%d): %d\n", G.netfd, len));
695 static int getport(char * p)
697 unsigned int port = atoi(p);
699 if ((unsigned)(port - 1 ) > 65534)
701 error_msg_and_die("%s: bad port number", p);
706 static struct in_addr getserver(char * host)
711 he = xgethostbyname(host);
712 memcpy(&addr, he->h_addr, sizeof addr);
714 TRACE(1, ("addr: %s\n", inet_ntoa(addr)));
719 static int create_socket(void)
721 return socket(AF_INET, SOCK_STREAM, 0);
724 static void setup_sockaddr_in(struct sockaddr_in * addr, int port)
726 memset(addr, 0, sizeof(struct sockaddr_in));
727 addr->sin_family = AF_INET;
728 addr->sin_port = htons(port);
732 static int local_bind(int port)
734 struct sockaddr_in s_addr;
735 int s = create_socket();
737 setup_sockaddr_in(&s_addr, port);
739 setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
741 if (bind(s, &s_addr, sizeof s_addr) < 0)
743 char * e = sys_errlist[errno];
744 syserrorexit("bind");
753 static int remote_connect(struct in_addr addr, int port)
755 struct sockaddr_in s_addr;
756 int s = create_socket();
758 setup_sockaddr_in(&s_addr, port);
759 s_addr.sin_addr = addr;
761 setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, &one, sizeof one);
763 if (connect(s, (struct sockaddr *)&s_addr, sizeof s_addr) < 0)
765 perror_msg_and_die("Unable to connect to remote host");
772 c-file-style: "linux"