| /* vi: set sw=4 ts=4: */ |
| /* |
| * telnet implementation for busybox |
| * |
| * Author: Tomi Ollila <too@iki.fi> |
| * Copyright (C) 1994-2000 by Tomi Ollila |
| * |
| * Created: Thu Apr 7 13:29:41 1994 too |
| * Last modified: Fri Jun 9 14:34:24 2000 too |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| * HISTORY |
| * Revision 3.1 1994/04/17 11:31:54 too |
| * initial revision |
| * Modified 2000/06/13 for inclusion into BusyBox by Erik Andersen <andersen@codepoet.org> |
| * Modified 2001/05/07 to add ability to pass TTYPE to remote host by Jim McQuillan |
| * <jam@ltsp.org> |
| * |
| */ |
| |
| #include <termios.h> |
| #include <unistd.h> |
| #include <errno.h> |
| #include <stdlib.h> |
| #include <stdarg.h> |
| #include <string.h> |
| #include <signal.h> |
| #include <arpa/telnet.h> |
| #include <sys/types.h> |
| #include <sys/socket.h> |
| #include <netinet/in.h> |
| #include "busybox.h" |
| |
| #if 0 |
| static const int DOTRACE = 1; |
| #endif |
| |
| #ifdef DOTRACE |
| #include <arpa/inet.h> /* for inet_ntoa()... */ |
| #define TRACE(x, y) do { if (x) printf y; } while (0) |
| #else |
| #define TRACE(x, y) |
| #endif |
| |
| #if 0 |
| #define USE_POLL |
| #include <sys/poll.h> |
| #else |
| #include <sys/time.h> |
| #endif |
| |
| #define DATABUFSIZE 128 |
| #define IACBUFSIZE 128 |
| |
| static const int CHM_TRY = 0; |
| static const int CHM_ON = 1; |
| static const int CHM_OFF = 2; |
| |
| static const int UF_ECHO = 0x01; |
| static const int UF_SGA = 0x02; |
| |
| enum { |
| TS_0 = 1, |
| TS_IAC = 2, |
| TS_OPT = 3, |
| TS_SUB1 = 4, |
| TS_SUB2 = 5, |
| }; |
| |
| #define WriteCS(fd, str) write(fd, str, sizeof str -1) |
| |
| typedef unsigned char byte; |
| |
| /* use globals to reduce size ??? */ /* test this hypothesis later */ |
| static struct Globalvars { |
| int netfd; /* console fd:s are 0 and 1 (and 2) */ |
| /* same buffer used both for network and console read/write */ |
| char buf[DATABUFSIZE]; /* allocating so static size is smaller */ |
| byte telstate; /* telnet negotiation state from network input */ |
| byte telwish; /* DO, DONT, WILL, WONT */ |
| byte charmode; |
| byte telflags; |
| byte gotsig; |
| /* buffer to handle telnet negotiations */ |
| char iacbuf[IACBUFSIZE]; |
| short iaclen; /* could even use byte */ |
| struct termios termios_def; |
| struct termios termios_raw; |
| } G; |
| |
| #define xUSE_GLOBALVAR_PTR /* xUSE... -> don't use :D (makes smaller code) */ |
| |
| #ifdef USE_GLOBALVAR_PTR |
| struct Globalvars * Gptr; |
| #define G (*Gptr) |
| #endif |
| |
| static inline void iacflush(void) |
| { |
| write(G.netfd, G.iacbuf, G.iaclen); |
| G.iaclen = 0; |
| } |
| |
| /* Function prototypes */ |
| static void rawmode(void); |
| static void cookmode(void); |
| static void do_linemode(void); |
| static void will_charmode(void); |
| static void telopt(byte c); |
| static int subneg(byte c); |
| |
| /* Some globals */ |
| static int one = 1; |
| |
| #ifdef CONFIG_FEATURE_TELNET_TTYPE |
| static char *ttype; |
| #endif |
| |
| #ifdef CONFIG_FEATURE_AUTOWIDTH |
| static int win_width, win_height; |
| #endif |
| |
| static void doexit(int ev) |
| { |
| cookmode(); |
| exit(ev); |
| } |
| |
| static void conescape(void) |
| { |
| char b; |
| |
| if (G.gotsig) /* came from line mode... go raw */ |
| rawmode(); |
| |
| WriteCS(1, "\r\nConsole escape. Commands are:\r\n\n" |
| " l go to line mode\r\n" |
| " c go to character mode\r\n" |
| " z suspend telnet\r\n" |
| " e exit telnet\r\n"); |
| |
| if (read(0, &b, 1) <= 0) |
| doexit(1); |
| |
| switch (b) |
| { |
| case 'l': |
| if (!G.gotsig) |
| { |
| do_linemode(); |
| goto rrturn; |
| } |
| break; |
| case 'c': |
| if (G.gotsig) |
| { |
| will_charmode(); |
| goto rrturn; |
| } |
| break; |
| case 'z': |
| cookmode(); |
| kill(0, SIGTSTP); |
| rawmode(); |
| break; |
| case 'e': |
| doexit(0); |
| } |
| |
| WriteCS(1, "continuing...\r\n"); |
| |
| if (G.gotsig) |
| cookmode(); |
| |
| rrturn: |
| G.gotsig = 0; |
| |
| } |
| static void handlenetoutput(int len) |
| { |
| /* here we could do smart tricks how to handle 0xFF:s in output |
| * stream like writing twice every sequence of FF:s (thus doing |
| * many write()s. But I think interactive telnet application does |
| * not need to be 100% 8-bit clean, so changing every 0xff:s to |
| * 0x7f:s |
| * |
| * 2002-mar-21, Przemyslaw Czerpak (druzus@polbox.com) |
| * I don't agree. |
| * first - I cannot use programs like sz/rz |
| * second - the 0x0D is sent as one character and if the next |
| * char is 0x0A then it's eaten by a server side. |
| * third - whay doy you have to make 'many write()s'? |
| * I don't understand. |
| * So I implemented it. It's realy useful for me. I hope that |
| * others people will find it interesting to. |
| */ |
| |
| int i, j; |
| byte * p = G.buf; |
| byte outbuf[4*DATABUFSIZE]; |
| |
| for (i = len, j = 0; i > 0; i--, p++) |
| { |
| if (*p == 0x1d) |
| { |
| conescape(); |
| return; |
| } |
| outbuf[j++] = *p; |
| if (*p == 0xff) |
| outbuf[j++] = 0xff; |
| else if (*p == 0x0d) |
| outbuf[j++] = 0x00; |
| } |
| if (j > 0 ) |
| write(G.netfd, outbuf, j); |
| } |
| |
| |
| static void handlenetinput(int len) |
| { |
| int i; |
| int cstart = 0; |
| |
| for (i = 0; i < len; i++) |
| { |
| byte c = G.buf[i]; |
| |
| if (G.telstate == 0) /* most of the time state == 0 */ |
| { |
| if (c == IAC) |
| { |
| cstart = i; |
| G.telstate = TS_IAC; |
| } |
| } |
| else |
| switch (G.telstate) |
| { |
| case TS_0: |
| if (c == IAC) |
| G.telstate = TS_IAC; |
| else |
| G.buf[cstart++] = c; |
| break; |
| |
| case TS_IAC: |
| if (c == IAC) /* IAC IAC -> 0xFF */ |
| { |
| G.buf[cstart++] = c; |
| G.telstate = TS_0; |
| break; |
| } |
| /* else */ |
| switch (c) |
| { |
| case SB: |
| G.telstate = TS_SUB1; |
| break; |
| case DO: |
| case DONT: |
| case WILL: |
| case WONT: |
| G.telwish = c; |
| G.telstate = TS_OPT; |
| break; |
| default: |
| G.telstate = TS_0; /* DATA MARK must be added later */ |
| } |
| break; |
| case TS_OPT: /* WILL, WONT, DO, DONT */ |
| telopt(c); |
| G.telstate = TS_0; |
| break; |
| case TS_SUB1: /* Subnegotiation */ |
| case TS_SUB2: /* Subnegotiation */ |
| if (subneg(c)) |
| G.telstate = TS_0; |
| break; |
| } |
| } |
| if (G.telstate) |
| { |
| if (G.iaclen) iacflush(); |
| if (G.telstate == TS_0) G.telstate = 0; |
| |
| len = cstart; |
| } |
| |
| if (len) |
| write(1, G.buf, len); |
| } |
| |
| |
| /* ******************************* */ |
| |
| static inline void putiac(int c) |
| { |
| G.iacbuf[G.iaclen++] = c; |
| } |
| |
| |
| static void putiac2(byte wwdd, byte c) |
| { |
| if (G.iaclen + 3 > IACBUFSIZE) |
| iacflush(); |
| |
| putiac(IAC); |
| putiac(wwdd); |
| putiac(c); |
| } |
| |
| #if 0 |
| static void putiac1(byte c) |
| { |
| if (G.iaclen + 2 > IACBUFSIZE) |
| iacflush(); |
| |
| putiac(IAC); |
| putiac(c); |
| } |
| #endif |
| |
| #ifdef CONFIG_FEATURE_TELNET_TTYPE |
| static void putiac_subopt(byte c, char *str) |
| { |
| int len = strlen(str) + 6; // ( 2 + 1 + 1 + strlen + 2 ) |
| |
| if (G.iaclen + len > IACBUFSIZE) |
| iacflush(); |
| |
| putiac(IAC); |
| putiac(SB); |
| putiac(c); |
| putiac(0); |
| |
| while(*str) |
| putiac(*str++); |
| |
| putiac(IAC); |
| putiac(SE); |
| } |
| #endif |
| |
| #ifdef CONFIG_FEATURE_AUTOWIDTH |
| static void putiac_naws(byte c, int x, int y) |
| { |
| if (G.iaclen + 9 > IACBUFSIZE) |
| iacflush(); |
| |
| putiac(IAC); |
| putiac(SB); |
| putiac(c); |
| |
| putiac((x >> 8) & 0xff); |
| putiac(x & 0xff); |
| putiac((y >> 8) & 0xff); |
| putiac(y & 0xff); |
| |
| putiac(IAC); |
| putiac(SE); |
| } |
| #endif |
| |
| /* void putiacstring (subneg strings) */ |
| |
| /* ******************************* */ |
| |
| static char const escapecharis[] = "\r\nEscape character is "; |
| |
| static void setConMode(void) |
| { |
| if (G.telflags & UF_ECHO) |
| { |
| if (G.charmode == CHM_TRY) { |
| G.charmode = CHM_ON; |
| printf("\r\nEntering character mode%s'^]'.\r\n", escapecharis); |
| rawmode(); |
| } |
| } |
| else |
| { |
| if (G.charmode != CHM_OFF) { |
| G.charmode = CHM_OFF; |
| printf("\r\nEntering line mode%s'^C'.\r\n", escapecharis); |
| cookmode(); |
| } |
| } |
| } |
| |
| /* ******************************* */ |
| |
| static void will_charmode(void) |
| { |
| G.charmode = CHM_TRY; |
| G.telflags |= (UF_ECHO | UF_SGA); |
| setConMode(); |
| |
| putiac2(DO, TELOPT_ECHO); |
| putiac2(DO, TELOPT_SGA); |
| iacflush(); |
| } |
| |
| static void do_linemode(void) |
| { |
| G.charmode = CHM_TRY; |
| G.telflags &= ~(UF_ECHO | UF_SGA); |
| setConMode(); |
| |
| putiac2(DONT, TELOPT_ECHO); |
| putiac2(DONT, TELOPT_SGA); |
| iacflush(); |
| } |
| |
| /* ******************************* */ |
| |
| static inline void to_notsup(char c) |
| { |
| if (G.telwish == WILL) putiac2(DONT, c); |
| else if (G.telwish == DO) putiac2(WONT, c); |
| } |
| |
| static inline void to_echo(void) |
| { |
| /* if server requests ECHO, don't agree */ |
| if (G.telwish == DO) { putiac2(WONT, TELOPT_ECHO); return; } |
| else if (G.telwish == DONT) return; |
| |
| if (G.telflags & UF_ECHO) |
| { |
| if (G.telwish == WILL) |
| return; |
| } |
| else |
| if (G.telwish == WONT) |
| return; |
| |
| if (G.charmode != CHM_OFF) |
| G.telflags ^= UF_ECHO; |
| |
| if (G.telflags & UF_ECHO) |
| putiac2(DO, TELOPT_ECHO); |
| else |
| putiac2(DONT, TELOPT_ECHO); |
| |
| setConMode(); |
| WriteCS(1, "\r\n"); /* sudden modec */ |
| } |
| |
| static inline void to_sga(void) |
| { |
| /* daemon always sends will/wont, client do/dont */ |
| |
| if (G.telflags & UF_SGA) |
| { |
| if (G.telwish == WILL) |
| return; |
| } |
| else |
| if (G.telwish == WONT) |
| return; |
| |
| if ((G.telflags ^= UF_SGA) & UF_SGA) /* toggle */ |
| putiac2(DO, TELOPT_SGA); |
| else |
| putiac2(DONT, TELOPT_SGA); |
| |
| return; |
| } |
| |
| #ifdef CONFIG_FEATURE_TELNET_TTYPE |
| static inline void to_ttype(void) |
| { |
| /* Tell server we will (or won't) do TTYPE */ |
| |
| if(ttype) |
| putiac2(WILL, TELOPT_TTYPE); |
| else |
| putiac2(WONT, TELOPT_TTYPE); |
| |
| return; |
| } |
| #endif |
| |
| #ifdef CONFIG_FEATURE_AUTOWIDTH |
| static inline void to_naws(void) |
| { |
| /* Tell server we will do NAWS */ |
| putiac2(WILL, TELOPT_NAWS); |
| return; |
| } |
| #endif |
| |
| static void telopt(byte c) |
| { |
| switch (c) |
| { |
| case TELOPT_ECHO: to_echo(); break; |
| case TELOPT_SGA: to_sga(); break; |
| #ifdef CONFIG_FEATURE_TELNET_TTYPE |
| case TELOPT_TTYPE: to_ttype();break; |
| #endif |
| #ifdef CONFIG_FEATURE_AUTOWIDTH |
| case TELOPT_NAWS: to_naws(); |
| putiac_naws(c, win_width, win_height); |
| break; |
| #endif |
| default: to_notsup(c); |
| break; |
| } |
| } |
| |
| |
| /* ******************************* */ |
| |
| /* subnegotiation -- ignore all (except TTYPE,NAWS) */ |
| |
| static int subneg(byte c) |
| { |
| switch (G.telstate) |
| { |
| case TS_SUB1: |
| if (c == IAC) |
| G.telstate = TS_SUB2; |
| #ifdef CONFIG_FEATURE_TELNET_TTYPE |
| else |
| if (c == TELOPT_TTYPE) |
| putiac_subopt(TELOPT_TTYPE,ttype); |
| #endif |
| break; |
| case TS_SUB2: |
| if (c == SE) |
| return TRUE; |
| G.telstate = TS_SUB1; |
| /* break; */ |
| } |
| return FALSE; |
| } |
| |
| /* ******************************* */ |
| |
| static void fgotsig(int sig) |
| { |
| G.gotsig = sig; |
| } |
| |
| |
| static void rawmode(void) |
| { |
| tcsetattr(0, TCSADRAIN, &G.termios_raw); |
| } |
| |
| static void cookmode(void) |
| { |
| tcsetattr(0, TCSADRAIN, &G.termios_def); |
| } |
| |
| extern int telnet_main(int argc, char** argv) |
| { |
| char *host; |
| char *port; |
| int len; |
| #ifdef USE_POLL |
| struct pollfd ufds[2]; |
| #else |
| fd_set readfds; |
| int maxfd; |
| #endif |
| |
| #ifdef CONFIG_FEATURE_AUTOWIDTH |
| get_terminal_width_height(0, &win_width, &win_height); |
| #endif |
| |
| #ifdef CONFIG_FEATURE_TELNET_TTYPE |
| ttype = getenv("TERM"); |
| #endif |
| |
| memset(&G, 0, sizeof G); |
| |
| if (tcgetattr(0, &G.termios_def) < 0) |
| exit(1); |
| |
| G.termios_raw = G.termios_def; |
| cfmakeraw(&G.termios_raw); |
| |
| if (argc < 2) bb_show_usage(); |
| port = (argc > 2)? argv[2] : "23"; |
| |
| host = argv[1]; |
| |
| G.netfd = xconnect(host, port); |
| |
| setsockopt(G.netfd, SOL_SOCKET, SO_KEEPALIVE, &one, sizeof one); |
| |
| signal(SIGINT, fgotsig); |
| |
| #ifdef USE_POLL |
| ufds[0].fd = 0; ufds[1].fd = G.netfd; |
| ufds[0].events = ufds[1].events = POLLIN; |
| #else |
| FD_ZERO(&readfds); |
| FD_SET(0, &readfds); |
| FD_SET(G.netfd, &readfds); |
| maxfd = G.netfd + 1; |
| #endif |
| |
| while (1) |
| { |
| #ifndef USE_POLL |
| fd_set rfds = readfds; |
| |
| switch (select(maxfd, &rfds, NULL, NULL, NULL)) |
| #else |
| switch (poll(ufds, 2, -1)) |
| #endif |
| { |
| case 0: |
| /* timeout */ |
| case -1: |
| /* error, ignore and/or log something, bay go to loop */ |
| if (G.gotsig) |
| conescape(); |
| else |
| sleep(1); |
| break; |
| default: |
| |
| #ifdef USE_POLL |
| if (ufds[0].revents) /* well, should check POLLIN, but ... */ |
| #else |
| if (FD_ISSET(0, &rfds)) |
| #endif |
| { |
| len = read(0, G.buf, DATABUFSIZE); |
| |
| if (len <= 0) |
| doexit(0); |
| |
| TRACE(0, ("Read con: %d\n", len)); |
| |
| handlenetoutput(len); |
| } |
| |
| #ifdef USE_POLL |
| if (ufds[1].revents) /* well, should check POLLIN, but ... */ |
| #else |
| if (FD_ISSET(G.netfd, &rfds)) |
| #endif |
| { |
| len = read(G.netfd, G.buf, DATABUFSIZE); |
| |
| if (len <= 0) |
| { |
| WriteCS(1, "Connection closed by foreign host.\r\n"); |
| doexit(1); |
| } |
| TRACE(0, ("Read netfd (%d): %d\n", G.netfd, len)); |
| |
| handlenetinput(len); |
| } |
| } |
| } |
| } |
| |
| /* |
| Local Variables: |
| c-file-style: "linux" |
| c-basic-offset: 4 |
| tab-width: 4 |
| End: |
| */ |