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/*
This file is part of GNUnet.
(C) 2010 Christian Grothoff
GNUnet 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 3, or (at your
option) any later version.
GNUnet 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 GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
/**
* @file vpn/gnunet-helper-hijack-dns.c
* @brief
* @author Philipp Tölke
*/
#include <platform.h>
#include "gnunet_common.h"
int
fork_and_exec (char *file, char *cmd[])
{
pid_t pid = fork ();
if (pid < 0)
{
fprintf (stderr, "could not fork: %s\n", strerror (errno));
return GNUNET_SYSERR;
}
int st = 0;
if (pid == 0)
{
execv (file, cmd);
}
else
{
waitpid (pid, &st, 0);
}
return WIFEXITED (st) && (WEXITSTATUS (st) == 0);
}
int
main (int argc, char **argv)
{
int delete = 0;
int port = 0;
char *virt_dns;
if (argc < 3)
return GNUNET_SYSERR;
if (strncmp (argv[1], "-d", 2) == 0)
{
if (argc < 3)
return GNUNET_SYSERR;
delete = 1;
port = atoi (argv[2]);
virt_dns = argv[3];
}
else
{
port = atoi (argv[1]);
virt_dns = argv[2];
}
if (port == 0)
return GNUNET_SYSERR;
struct stat s;
if (stat ("/sbin/iptables", &s) < 0)
{
fprintf (stderr, "stat on /sbin/iptables failed: %s\n", strerror (errno));
return GNUNET_SYSERR;
}
if (stat ("/sbin/ip", &s) < 0)
{
fprintf (stderr, "stat on /sbin/ip failed: %s\n", strerror (errno));
return GNUNET_SYSERR;
}
char localport[7];
snprintf (localport, 7, "%d", port);
int r;
if (delete)
{
e4:
r = fork_and_exec ("/sbin/ip", (char *[])
{
"ip", "route", "del", "default", "via", virt_dns,
"table", "2", NULL});
e3:
r = fork_and_exec ("/sbin/ip", (char *[])
{
"ip", "rule", "del", "fwmark", "3", "table", "2", NULL});
e2:
r = fork_and_exec ("/sbin/iptables", (char *[])
{
"iptables", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
"--dport", "53", "-j", "MARK", "--set-mark", "3", NULL});
e1:
r = fork_and_exec ("/sbin/iptables", (char *[])
{
"iptables", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
"--sport", localport, "--dport", "53", "-j", "ACCEPT",
NULL});
if (!delete)
r = 0;
}
else
{
r = fork_and_exec ("/sbin/iptables", (char *[])
{
"iptables", "-t", "mangle", "-I", "OUTPUT", "1", "-p",
"udp", "--sport", localport, "--dport", "53", "-j",
"ACCEPT", NULL});
if (!r)
goto e1;
r = fork_and_exec ("/sbin/iptables", (char *[])
{
"iptables", "-t", "mangle", "-I", "OUTPUT", "2", "-p",
"udp", "--dport", "53", "-j", "MARK", "--set-mark", "3",
NULL});
if (!r)
goto e2;
r = fork_and_exec ("/sbin/ip", (char *[])
{
"ip", "rule", "add", "fwmark", "3", "table", "2", NULL});
if (!r)
goto e3;
r = fork_and_exec ("/sbin/ip", (char *[])
{
"ip", "route", "add", "default", "via", virt_dns,
"table", "2", NULL});
if (!r)
goto e4;
}
if (r)
return GNUNET_YES;
return GNUNET_SYSERR;
}
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