mirror of
https://github.com/sheumann/hush.git
synced 2024-08-17 00:29:03 +00:00
504 lines
14 KiB
C
504 lines
14 KiB
C
|
/* vi: set sw=4 ts=4: */
|
||
|
/*
|
||
|
* $Id: telnet.c,v 1.1 2000/02/22 17:17:45 erik Exp $
|
||
|
* Mini telnet implementation for busybox
|
||
|
*
|
||
|
* Copyright (C) 2000 by Randolph Chung <tausq@debian.org>
|
||
|
*
|
||
|
* 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
|
||
|
*
|
||
|
* This version of telnet is adapted (but very heavily modified) from the
|
||
|
* telnet in netkit-telnet 0.16, which is:
|
||
|
*
|
||
|
* Copyright (c) 1989 The Regents of the University of California.
|
||
|
* All rights reserved.
|
||
|
*
|
||
|
* Original copyright notice is retained at the end of this file.
|
||
|
*/
|
||
|
|
||
|
#include "internal.h"
|
||
|
#include <stdio.h>
|
||
|
#include <stdlib.h>
|
||
|
#include <unistd.h>
|
||
|
#include <ctype.h>
|
||
|
#include <signal.h>
|
||
|
#include <errno.h>
|
||
|
#include <netdb.h>
|
||
|
#include <termios.h>
|
||
|
#include <netinet/in.h>
|
||
|
#include <sys/types.h>
|
||
|
#include <sys/socket.h>
|
||
|
#include <sys/ioctl.h>
|
||
|
#define TELOPTS
|
||
|
#include <arpa/telnet.h>
|
||
|
#include <arpa/inet.h>
|
||
|
|
||
|
static int STDIN = 0;
|
||
|
static int STDOUT = 1;
|
||
|
static const char *telnet_usage = "telnet host [port]\n\n";
|
||
|
static struct termios saved_tc;
|
||
|
static unsigned char options[NTELOPTS];
|
||
|
static char tr_state = 0; /* telnet send and receive state */
|
||
|
static unsigned char subbuffer[256];
|
||
|
static unsigned char *subpointer, *subend;
|
||
|
#define SB_CLEAR() subpointer = subbuffer;
|
||
|
#define SB_TERM() { subend = subpointer; SB_CLEAR(); }
|
||
|
#define SB_ACCUM(c) if (subpointer < (subbuffer+sizeof subbuffer)) { *subpointer++ = (c); }
|
||
|
#define SB_GET() (*subpointer++)
|
||
|
#define SB_PEEK() (*subpointer)
|
||
|
#define SB_EOF() (subpointer >= subend)
|
||
|
#define SB_LEN() (subend - subpointer)
|
||
|
|
||
|
#define TELNETPORT 23
|
||
|
#define MASK_WILL 0x01
|
||
|
#define MASK_WONT 0x04
|
||
|
#define MASK_DO 0x10
|
||
|
#define MASK_DONT 0x40
|
||
|
|
||
|
#define TFLAG_ISSET(opt, flag) (options[opt] & MASK_##flag)
|
||
|
#define TFLAG_SET(opt, flag) (options[opt] |= MASK_##flag)
|
||
|
#define TFLAG_CLR(opt, flag) (options[opt] &= ~MASK_##flag)
|
||
|
|
||
|
#define PERROR(ctx) do { fprintf(stderr, "%s: %s\n", ctx, strerror(errno)); \
|
||
|
return; } while (0)
|
||
|
|
||
|
#define TS_DATA 0
|
||
|
#define TS_IAC 1
|
||
|
#define TS_WILL 2
|
||
|
#define TS_WONT 3
|
||
|
#define TS_DO 4
|
||
|
#define TS_DONT 5
|
||
|
#define TS_CR 6
|
||
|
#define TS_SB 7 /* sub-option collection */
|
||
|
#define TS_SE 8 /* looking for sub-option end */
|
||
|
|
||
|
/* prototypes */
|
||
|
static void telnet_init(void);
|
||
|
static void telnet_start(char *host, int port);
|
||
|
static void telnet_shutdown(void);
|
||
|
/* ******************************************************************* */
|
||
|
#define SENDCOMMAND(c,o) \
|
||
|
char buf[3]; \
|
||
|
buf[0] = IAC; buf[1] = c; buf[2] = o; \
|
||
|
write(s, buf, sizeof(buf));
|
||
|
|
||
|
static inline void telnet_sendwill(int s, int c) { SENDCOMMAND(WILL, c); }
|
||
|
static inline void telnet_sendwont(int s, int c) { SENDCOMMAND(WONT, c); }
|
||
|
static inline void telnet_senddo(int s, int c) { SENDCOMMAND(DO, c); }
|
||
|
static inline void telnet_senddont(int s, int c) { SENDCOMMAND(DONT, c); }
|
||
|
|
||
|
static void telnet_setoptions(int s)
|
||
|
{
|
||
|
/*
|
||
|
telnet_senddo(s, TELOPT_SGA); TFLAG_SET(TELOPT_SGA, DO);
|
||
|
telnet_sendwill(s, TELOPT_NAWS); TFLAG_SET(TELOPT_NAWS, WILL);
|
||
|
telnet_sendwill(s, TELOPT_TSPEED); TFLAG_SET(TELOPT_TSPEED, WILL);
|
||
|
telnet_sendwill(s, TELOPT_LFLOW); TFLAG_SET(TELOPT_LFLOW, WILL);
|
||
|
telnet_sendwill(s, TELOPT_LINEMODE); TFLAG_SET(TELOPT_LINEMODE, WILL);
|
||
|
telnet_sendwill(s, TELOPT_NEW_ENVIRON); TFLAG_SET(TELOPT_NEW_ENVIRON, WILL);
|
||
|
telnet_senddo(s, TELOPT_STATUS); TFLAG_SET(TELOPT_STATUS, DO);
|
||
|
telnet_sendwill(s, TELOPT_TTYPE); TFLAG_SET(TELOPT_TTYPE, WILL);
|
||
|
*/
|
||
|
telnet_senddo(s, TELOPT_BINARY); TFLAG_SET(TELOPT_BINARY, DO);
|
||
|
telnet_sendwill(s, TELOPT_BINARY); TFLAG_SET(TELOPT_BINARY, WILL);
|
||
|
}
|
||
|
|
||
|
static void telnet_suboptions(int net)
|
||
|
{
|
||
|
char buf[256];
|
||
|
switch (SB_GET()) {
|
||
|
case TELOPT_TTYPE:
|
||
|
if (TFLAG_ISSET(TELOPT_TTYPE, WONT)) return;
|
||
|
if (SB_EOF() || SB_GET() != TELQUAL_SEND) {
|
||
|
return;
|
||
|
} else {
|
||
|
const char *name = getenv("TERM");
|
||
|
if (name) {
|
||
|
snprintf(buf, sizeof(buf), "%c%c%c%c%s%c%c", IAC, SB,
|
||
|
TELOPT_TTYPE, TELQUAL_IS, name, IAC, SE);
|
||
|
write(net, buf, strlen(name)+6);
|
||
|
}
|
||
|
}
|
||
|
break;
|
||
|
case TELOPT_TSPEED:
|
||
|
if (TFLAG_ISSET(TELOPT_TSPEED, WONT)) return;
|
||
|
if (SB_EOF()) return;
|
||
|
if (SB_GET() == TELQUAL_SEND) {
|
||
|
/*
|
||
|
long oospeed, iispeed;
|
||
|
netoring.printf("%c%c%c%c%ld,%ld%c%c", IAC, SB, TELOPT_TSPEED,
|
||
|
TELQUAL_IS, oospeed, iispeed, IAC, SE);
|
||
|
*/
|
||
|
}
|
||
|
break;
|
||
|
/*
|
||
|
case TELOPT_LFLOW:
|
||
|
if (TFLAG_ISSET(TELOPT_LFLOW, WONT)) return;
|
||
|
if (SB_EOF()) return;
|
||
|
switch(SB_GET()) {
|
||
|
case 1: localflow = 1; break;
|
||
|
case 0: localflow = 0; break;
|
||
|
default: return;
|
||
|
}
|
||
|
break;
|
||
|
case TELOPT_LINEMODE:
|
||
|
if (TFLAG_ISSET(TELOPT_LINEMODE, WONT)) return;
|
||
|
if (SB_EOF()) return;
|
||
|
switch (SB_GET()) {
|
||
|
case WILL: lm_will(subpointer, SB_LEN()); break;
|
||
|
case WONT: lm_wont(subpointer, SB_LEN()); break;
|
||
|
case DO: lm_do(subpointer, SB_LEN()); break;
|
||
|
case DONT: lm_dont(subpointer, SB_LEN()); break;
|
||
|
case LM_SLC: slc(subpointer, SB_LEN()); break;
|
||
|
case LM_MODE: lm_mode(subpointer, SB_LEN(), 0); break;
|
||
|
default: break;
|
||
|
}
|
||
|
break;
|
||
|
case TELOPT_ENVIRON:
|
||
|
if (SB_EOF()) return;
|
||
|
switch(SB_PEEK()) {
|
||
|
case TELQUAL_IS:
|
||
|
case TELQUAL_INFO:
|
||
|
if (TFLAG_ISSET(TELOPT_ENVIRON, DONT)) return;
|
||
|
break;
|
||
|
case TELQUAL_SEND:
|
||
|
if (TFLAG_ISSET(TELOPT_ENVIRON, WONT)) return;
|
||
|
break;
|
||
|
default:
|
||
|
return;
|
||
|
}
|
||
|
env_opt(subpointer, SB_LEN());
|
||
|
break;
|
||
|
*/
|
||
|
case TELOPT_XDISPLOC:
|
||
|
if (TFLAG_ISSET(TELOPT_XDISPLOC, WONT)) return;
|
||
|
if (SB_EOF()) return;
|
||
|
if (SB_GET() == TELQUAL_SEND) {
|
||
|
const char *dp = getenv("DISPLAY");
|
||
|
if (dp) {
|
||
|
snprintf(buf, sizeof(buf), "%c%c%c%c%s%c%c", IAC, SB,
|
||
|
TELOPT_XDISPLOC, TELQUAL_IS, dp, IAC, SE);
|
||
|
write(net, buf, strlen(dp)+6);
|
||
|
}
|
||
|
}
|
||
|
break;
|
||
|
default:
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
static void sighandler(int sig)
|
||
|
{
|
||
|
telnet_shutdown();
|
||
|
exit(0);
|
||
|
}
|
||
|
|
||
|
static int telnet_send(int tty, int net)
|
||
|
{
|
||
|
int ret;
|
||
|
unsigned char ch;
|
||
|
|
||
|
while ((ret = read(tty, &ch, 1)) > 0) {
|
||
|
if (ch == 29) { /* 29 -- ctrl-] */
|
||
|
/* do something here? */
|
||
|
exit(0);
|
||
|
} else {
|
||
|
ret = write(net, &ch, 1);
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
if (ret == -1 && errno == EWOULDBLOCK) return 1;
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
static int telnet_recv(int net, int tty)
|
||
|
{
|
||
|
/* globals: tr_state - telnet receive state */
|
||
|
int ret, c = 0;
|
||
|
unsigned char ch;
|
||
|
|
||
|
while ((ret = read(net, &ch, 1)) > 0) {
|
||
|
c = ch;
|
||
|
/* printf("%02X ", c); fflush(stdout); */
|
||
|
switch (tr_state) {
|
||
|
case TS_DATA:
|
||
|
if (c == IAC) {
|
||
|
tr_state = TS_IAC;
|
||
|
break;
|
||
|
} else {
|
||
|
write(tty, &c, 1);
|
||
|
}
|
||
|
break;
|
||
|
case TS_IAC:
|
||
|
switch (c) {
|
||
|
case WILL:
|
||
|
tr_state = TS_WILL; break;
|
||
|
case WONT:
|
||
|
tr_state = TS_WONT; break;
|
||
|
case DO:
|
||
|
tr_state = TS_DO; break;
|
||
|
case DONT:
|
||
|
tr_state = TS_DONT; break;
|
||
|
case SB:
|
||
|
SB_CLEAR();
|
||
|
tr_state = TS_SB; break;
|
||
|
case IAC:
|
||
|
write(tty, &c, 1); /* fallthrough */
|
||
|
default:
|
||
|
tr_state = TS_DATA;
|
||
|
}
|
||
|
|
||
|
/* subnegotiation -- ignored for now */
|
||
|
case TS_SB:
|
||
|
if (c == IAC) tr_state = TS_SE;
|
||
|
else SB_ACCUM(c);
|
||
|
break;
|
||
|
case TS_SE:
|
||
|
if (c == IAC) {
|
||
|
SB_ACCUM(IAC);
|
||
|
tr_state = TS_SB;
|
||
|
} else if (c == SE) {
|
||
|
SB_ACCUM(IAC);
|
||
|
SB_ACCUM(SE);
|
||
|
subpointer -= 2;
|
||
|
SB_TERM();
|
||
|
telnet_suboptions(net);
|
||
|
tr_state = TS_DATA;
|
||
|
}
|
||
|
/* otherwise this is an error, but we ignore it for now */
|
||
|
break;
|
||
|
/* handle incoming requests */
|
||
|
case TS_WILL:
|
||
|
printf("WILL %s\n", telopts[c]);
|
||
|
if (!TFLAG_ISSET(c, DO)) {
|
||
|
if (c == TELOPT_BINARY) {
|
||
|
TFLAG_SET(c, DO);
|
||
|
TFLAG_CLR(c, DONT);
|
||
|
telnet_senddo(net, c);
|
||
|
} else {
|
||
|
TFLAG_SET(c, DONT);
|
||
|
telnet_senddont(net, c);
|
||
|
}
|
||
|
}
|
||
|
telnet_senddont(net, c);
|
||
|
tr_state = TS_DATA;
|
||
|
break;
|
||
|
case TS_WONT:
|
||
|
printf("WONT %s\n", telopts[c]);
|
||
|
if (!TFLAG_ISSET(c, DONT)) {
|
||
|
TFLAG_SET(c, DONT);
|
||
|
TFLAG_CLR(c, DO);
|
||
|
telnet_senddont(net, c);
|
||
|
}
|
||
|
tr_state = TS_DATA;
|
||
|
break;
|
||
|
case TS_DO:
|
||
|
printf("DO %s\n", telopts[c]);
|
||
|
if (!TFLAG_ISSET(c, WILL)) {
|
||
|
if (c == TELOPT_BINARY) {
|
||
|
TFLAG_SET(c, WILL);
|
||
|
TFLAG_CLR(c, WONT);
|
||
|
telnet_sendwill(net, c);
|
||
|
} else {
|
||
|
TFLAG_SET(c, WONT);
|
||
|
telnet_sendwont(net, c);
|
||
|
}
|
||
|
}
|
||
|
tr_state = TS_DATA;
|
||
|
break;
|
||
|
case TS_DONT:
|
||
|
printf("DONT %s\n", telopts[c]);
|
||
|
if (!TFLAG_ISSET(c, WONT)) {
|
||
|
TFLAG_SET(c, WONT);
|
||
|
TFLAG_CLR(c, WILL);
|
||
|
telnet_sendwont(net, c);
|
||
|
}
|
||
|
tr_state = TS_DATA;
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
}
|
||
|
if (ret == -1 && errno == EWOULDBLOCK) return 1;
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
/* ******************************************************************* */
|
||
|
static void telnet_init(void)
|
||
|
{
|
||
|
struct termios tmp_tc;
|
||
|
cc_t esc = (']' & 0x1f); /* ctrl-] */
|
||
|
|
||
|
memset(options, 0, sizeof(options));
|
||
|
SB_CLEAR();
|
||
|
|
||
|
tcgetattr(STDIN, &saved_tc);
|
||
|
|
||
|
tmp_tc = saved_tc;
|
||
|
tmp_tc.c_lflag &= ~ECHO; /* echo */
|
||
|
tmp_tc.c_oflag |= ONLCR; /* NL->CRLF translation */
|
||
|
tmp_tc.c_iflag |= ICRNL;
|
||
|
tmp_tc.c_iflag &= ~(IXANY|IXOFF|IXON); /* no flow control */
|
||
|
tmp_tc.c_lflag |= ISIG; /* trap signals */
|
||
|
tmp_tc.c_lflag &= ~ICANON; /* edit mode */
|
||
|
|
||
|
/* misc settings, compat with default telnet stuff */
|
||
|
tmp_tc.c_oflag &= ~TABDLY;
|
||
|
|
||
|
/* 8-bit clean */
|
||
|
tmp_tc.c_iflag &= ~ISTRIP;
|
||
|
tmp_tc.c_cflag &= ~(CSIZE|PARENB);
|
||
|
tmp_tc.c_cflag |= saved_tc.c_cflag & (CSIZE|PARENB);
|
||
|
tmp_tc.c_oflag |= OPOST;
|
||
|
|
||
|
/* set escape character */
|
||
|
tmp_tc.c_cc[VEOL] = esc;
|
||
|
tcsetattr(STDIN, TCSADRAIN, &tmp_tc);
|
||
|
}
|
||
|
|
||
|
static void telnet_start(char *hostname, int port)
|
||
|
{
|
||
|
struct hostent *host = 0;
|
||
|
struct sockaddr_in addr;
|
||
|
int s, c;
|
||
|
fd_set rfds, wfds;
|
||
|
|
||
|
memset(&addr, 0, sizeof(addr));
|
||
|
host = gethostbyname(hostname);
|
||
|
if (!host) {
|
||
|
fprintf(stderr, "Unknown host: %s\n", hostname);
|
||
|
return;
|
||
|
}
|
||
|
addr.sin_family = host->h_addrtype;
|
||
|
memcpy(&addr.sin_addr, host->h_addr, sizeof(addr.sin_addr));
|
||
|
addr.sin_port = htons(port);
|
||
|
|
||
|
printf("Trying %s...\n", inet_ntoa(addr.sin_addr));
|
||
|
|
||
|
if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) PERROR("socket");
|
||
|
if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) < 0)
|
||
|
PERROR("connect");
|
||
|
printf("Connected to %s\n", hostname);
|
||
|
printf("Escape character is ^]\n");
|
||
|
|
||
|
signal(SIGINT, sighandler);
|
||
|
signal(SIGQUIT, sighandler);
|
||
|
signal(SIGPIPE, sighandler);
|
||
|
signal(SIGWINCH, sighandler);
|
||
|
|
||
|
/* make inputs nonblocking */
|
||
|
c = 1;
|
||
|
ioctl(s, FIONBIO, &c);
|
||
|
ioctl(STDIN, FIONBIO, &c);
|
||
|
|
||
|
if (port == TELNETPORT) telnet_setoptions(s);
|
||
|
|
||
|
/* shuttle data back and forth between tty and socket */
|
||
|
while (1) {
|
||
|
FD_ZERO(&rfds);
|
||
|
FD_ZERO(&wfds);
|
||
|
|
||
|
FD_SET(s, &rfds);
|
||
|
/* FD_SET(s, &wfds); */
|
||
|
FD_SET(STDIN, &rfds);
|
||
|
/* FD_SET(STDOUT, &wfds); */
|
||
|
|
||
|
if ((c = select(s+1, &rfds, &wfds, 0, 0))) {
|
||
|
if (c == -1) {
|
||
|
/* handle errors */
|
||
|
PERROR("select");
|
||
|
}
|
||
|
if (FD_ISSET(s, &rfds)) {
|
||
|
/* input from network */
|
||
|
FD_CLR(s, &rfds);
|
||
|
c = telnet_recv(s, STDOUT);
|
||
|
if (c == 0) break;
|
||
|
if (c < 0) PERROR("telnet_recv");
|
||
|
}
|
||
|
if (FD_ISSET(STDIN, &rfds)) {
|
||
|
/* input from tty */
|
||
|
FD_CLR(STDIN, &rfds);
|
||
|
c = telnet_send(STDIN, s);
|
||
|
if (c == 0) break;
|
||
|
if (c < 0) PERROR("telnet_send");
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
return;
|
||
|
}
|
||
|
|
||
|
static void telnet_shutdown(void)
|
||
|
{
|
||
|
printf("\n");
|
||
|
tcsetattr(STDIN, TCSANOW, &saved_tc);
|
||
|
}
|
||
|
|
||
|
#ifdef STANDALONE_TELNET
|
||
|
void usage(const char *msg)
|
||
|
{
|
||
|
printf("%s", msg);
|
||
|
exit(0);
|
||
|
}
|
||
|
|
||
|
int main(int argc, char **argv)
|
||
|
#else
|
||
|
int telnet_main(int argc, char **argv)
|
||
|
#endif
|
||
|
{
|
||
|
int port = TELNETPORT;
|
||
|
|
||
|
argc--; argv++;
|
||
|
if (argc < 1) usage(telnet_usage);
|
||
|
if (argc > 1) port = atoi(argv[1]);
|
||
|
telnet_init();
|
||
|
atexit(telnet_shutdown);
|
||
|
|
||
|
telnet_start(argv[0], port);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Copyright (c) 1988, 1990 Regents of the University of California.
|
||
|
* All rights reserved.
|
||
|
*
|
||
|
* Redistribution and use in source and binary forms, with or without
|
||
|
* modification, are permitted provided that the following conditions
|
||
|
* are met:
|
||
|
* 1. Redistributions of source code must retain the above copyright
|
||
|
* notice, this list of conditions and the following disclaimer.
|
||
|
* 2. Redistributions in binary form must reproduce the above copyright
|
||
|
* notice, this list of conditions and the following disclaimer in the
|
||
|
* documentation and/or other materials provided with the distribution.
|
||
|
* 3. All advertising materials mentioning features or use of this software
|
||
|
* must display the following acknowledgement:
|
||
|
* This product includes software developed by the University of
|
||
|
* California, Berkeley and its contributors.
|
||
|
* 4. Neither the name of the University nor the names of its contributors
|
||
|
* may be used to endorse or promote products derived from this software
|
||
|
* without specific prior written permission.
|
||
|
*
|
||
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
||
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
||
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
||
|
* SUCH DAMAGE.
|
||
|
*/
|