2006-06-05 12:41:08 +00:00
|
|
|
/*
|
2006-06-05 14:15:53 +00:00
|
|
|
* Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>, Erik Ekman <yarrick@kryo.se>
|
2006-06-05 12:41:08 +00:00
|
|
|
*
|
|
|
|
* Permission to use, copy, modify, and distribute this software for any
|
|
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
|
|
* copyright notice and this permission notice appear in all copies.
|
|
|
|
*
|
|
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
|
|
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
|
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
|
|
|
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
|
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
|
|
|
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
|
|
|
|
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <stdio.h>
|
2006-06-05 12:48:30 +00:00
|
|
|
#include <stdint.h>
|
2006-06-05 17:22:35 +00:00
|
|
|
#include <stdlib.h>
|
2006-06-05 14:43:04 +00:00
|
|
|
#include <string.h>
|
2006-06-05 14:46:10 +00:00
|
|
|
#include <signal.h>
|
2006-06-05 15:13:30 +00:00
|
|
|
#include <unistd.h>
|
|
|
|
#include <sys/types.h>
|
2006-06-05 23:34:23 +00:00
|
|
|
#include <sys/stat.h>
|
|
|
|
#include <fcntl.h>
|
2006-06-05 14:43:04 +00:00
|
|
|
#include <err.h>
|
2006-06-09 20:35:26 +00:00
|
|
|
#include <pwd.h>
|
2006-06-06 00:17:28 +00:00
|
|
|
#include <arpa/inet.h>
|
2006-06-06 17:59:24 +00:00
|
|
|
#include <zlib.h>
|
2006-06-05 12:41:08 +00:00
|
|
|
|
|
|
|
#include "tun.h"
|
2006-06-05 13:38:10 +00:00
|
|
|
#include "dns.h"
|
2006-06-05 12:41:08 +00:00
|
|
|
|
2006-06-06 00:18:29 +00:00
|
|
|
#ifndef MAX
|
|
|
|
#define MAX(a,b) ((a)>(b)?(a):(b))
|
|
|
|
#endif
|
|
|
|
|
2006-06-05 23:34:23 +00:00
|
|
|
#define FRAMESIZE (64*1024)
|
|
|
|
|
2006-06-05 14:46:10 +00:00
|
|
|
int running = 1;
|
|
|
|
|
|
|
|
static void
|
|
|
|
sigint(int sig) {
|
|
|
|
running = 0;
|
|
|
|
}
|
|
|
|
|
2006-06-05 14:43:04 +00:00
|
|
|
static int
|
|
|
|
tunnel(int tun_fd, int dns_fd)
|
|
|
|
{
|
|
|
|
int i;
|
2006-06-05 15:31:07 +00:00
|
|
|
int read;
|
2006-06-05 14:43:04 +00:00
|
|
|
fd_set fds;
|
2006-06-05 15:31:07 +00:00
|
|
|
struct timeval tv;
|
2006-06-05 23:34:23 +00:00
|
|
|
struct tun_frame *frame;
|
2006-06-06 17:59:24 +00:00
|
|
|
long buflen;
|
|
|
|
char buf[64*1024];
|
2006-06-05 23:34:23 +00:00
|
|
|
|
|
|
|
frame = malloc(FRAMESIZE);
|
|
|
|
|
2006-06-05 14:46:10 +00:00
|
|
|
while (running) {
|
2006-06-06 11:55:21 +00:00
|
|
|
tv.tv_sec = 1;
|
|
|
|
tv.tv_usec = 0;
|
2006-06-05 14:43:04 +00:00
|
|
|
|
|
|
|
FD_ZERO(&fds);
|
2006-06-06 02:39:37 +00:00
|
|
|
if (!dns_sending())
|
2006-06-05 20:05:11 +00:00
|
|
|
FD_SET(tun_fd, &fds);
|
2006-06-05 14:43:04 +00:00
|
|
|
FD_SET(dns_fd, &fds);
|
|
|
|
|
|
|
|
i = select(MAX(tun_fd, dns_fd) + 1, &fds, NULL, NULL, &tv);
|
|
|
|
|
|
|
|
if(i < 0) {
|
2006-06-05 15:22:29 +00:00
|
|
|
if (running) {
|
|
|
|
warn("select");
|
|
|
|
}
|
2006-06-05 14:43:04 +00:00
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
if(i == 0) {
|
2006-06-05 23:49:18 +00:00
|
|
|
dns_ping(dns_fd);
|
2006-06-05 14:43:04 +00:00
|
|
|
} else {
|
|
|
|
if(FD_ISSET(tun_fd, &fds)) {
|
2006-06-05 23:34:23 +00:00
|
|
|
read = read_tun(tun_fd, frame, FRAMESIZE);
|
2006-06-05 20:05:11 +00:00
|
|
|
if (read > 0) {
|
2006-06-06 18:05:16 +00:00
|
|
|
printf("Got data on tun! %d bytes\n", read);
|
2006-06-06 17:59:24 +00:00
|
|
|
buflen = sizeof(buf);
|
|
|
|
compress2(buf, &buflen, frame->data, read - 4, 9);
|
|
|
|
dns_handle_tun(dns_fd, buf, buflen);
|
2006-06-05 20:05:11 +00:00
|
|
|
}
|
2006-06-05 14:43:04 +00:00
|
|
|
}
|
|
|
|
if(FD_ISSET(dns_fd, &fds)) {
|
2006-06-06 18:02:18 +00:00
|
|
|
read = dns_read(dns_fd, buf, FRAMESIZE-4);
|
2006-06-05 20:05:11 +00:00
|
|
|
if (read > 0) {
|
2006-06-06 17:59:24 +00:00
|
|
|
buflen = 64*1024-4;
|
|
|
|
uncompress(frame->data, &buflen, buf, read);
|
|
|
|
|
2006-06-05 20:05:11 +00:00
|
|
|
printf("Got data on dns! %d bytes\n", read);
|
2006-06-05 23:35:48 +00:00
|
|
|
|
2006-06-06 11:09:13 +00:00
|
|
|
frame->flags = htons(0x0000);
|
2006-06-06 00:39:29 +00:00
|
|
|
#ifdef LINUX
|
2006-06-06 11:09:13 +00:00
|
|
|
frame->proto = htons(0x0800); // Linux wants ETH_P_IP
|
2006-06-06 00:39:29 +00:00
|
|
|
#else
|
2006-06-06 11:09:13 +00:00
|
|
|
frame->proto = htons(0x0002); // BSD wants AF_INET as long word
|
2006-06-06 00:39:29 +00:00
|
|
|
#endif
|
2006-06-06 00:17:28 +00:00
|
|
|
|
2006-06-06 17:59:24 +00:00
|
|
|
write_tun(tun_fd, frame, buflen + 4);
|
2006-06-06 16:00:27 +00:00
|
|
|
if (!dns_sending()) {
|
|
|
|
dns_ping(dns_fd);
|
|
|
|
}
|
2006-06-05 20:05:11 +00:00
|
|
|
}
|
2006-06-05 14:43:04 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2006-06-05 23:34:23 +00:00
|
|
|
free(frame);
|
|
|
|
|
2006-06-05 14:43:04 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2006-06-09 20:35:26 +00:00
|
|
|
static void
|
|
|
|
usage() {
|
|
|
|
printf("Usage: dnstun [-u user] nameserver topdomain\n");
|
|
|
|
exit(2);
|
|
|
|
}
|
|
|
|
|
2006-06-05 12:41:08 +00:00
|
|
|
int
|
2006-06-05 17:22:35 +00:00
|
|
|
main(int argc, char **argv)
|
2006-06-05 12:41:08 +00:00
|
|
|
{
|
2006-06-05 14:43:04 +00:00
|
|
|
int tun_fd;
|
|
|
|
int dns_fd;
|
2006-06-09 20:35:26 +00:00
|
|
|
int choice;
|
|
|
|
char *username;
|
|
|
|
struct passwd *pw;
|
|
|
|
|
|
|
|
username = NULL;
|
|
|
|
while ((choice = getopt(argc, argv, "u:")) != -1) {
|
|
|
|
switch(choice) {
|
|
|
|
case 'u':
|
|
|
|
username = optarg;
|
|
|
|
pw = getpwnam(username);
|
|
|
|
if (!pw) {
|
|
|
|
printf("User %s does not exist!\n", username);
|
|
|
|
usage();
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
usage();
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
argc -= optind;
|
|
|
|
argv += optind;
|
2006-06-05 13:38:10 +00:00
|
|
|
|
2006-06-09 20:35:26 +00:00
|
|
|
if (argc != 2) {
|
|
|
|
usage();
|
2006-06-05 17:22:35 +00:00
|
|
|
}
|
|
|
|
|
2006-06-05 14:43:04 +00:00
|
|
|
tun_fd = open_tun();
|
2006-06-09 20:35:26 +00:00
|
|
|
dns_fd = open_dns(argv[0], argv[1]);
|
|
|
|
printf("Sending queries for %s to %s\n", argv[1], argv[0]);
|
2006-06-05 14:46:10 +00:00
|
|
|
|
|
|
|
signal(SIGINT, sigint);
|
|
|
|
|
2006-06-09 20:35:26 +00:00
|
|
|
if (username) {
|
|
|
|
if (setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0) {
|
|
|
|
printf("Could not switch to user %s!\n", username);
|
|
|
|
usage();
|
|
|
|
}
|
|
|
|
printf("Now running as user %s\n", username);
|
|
|
|
}
|
|
|
|
|
2006-06-05 14:43:04 +00:00
|
|
|
tunnel(tun_fd, dns_fd);
|
2006-06-05 12:41:08 +00:00
|
|
|
|
2006-06-05 14:46:10 +00:00
|
|
|
printf("Closing tunnel\n");
|
|
|
|
|
2006-06-05 14:43:04 +00:00
|
|
|
close_dns(dns_fd);
|
2006-06-06 11:09:13 +00:00
|
|
|
close_tun(tun_fd);
|
2006-06-05 12:41:08 +00:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|