hans/tun.cpp
2013-04-20 04:06:05 +02:00

114 lines
3.0 KiB
C++

/*
* Hans - IP over ICMP
* Copyright (C) 2009 Friedrich Schöller <hans@schoeller.se>
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "tun.h"
#include "exception.h"
#include "utility.h"
#include <arpa/inet.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <syslog.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
typedef ip IpHeader;
using namespace std;
Tun::Tun(const char *device, int mtu)
{
this->mtu = mtu;
if (device != NULL)
{
strncpy(this->device, device, VTUN_DEV_LEN);
this->device[VTUN_DEV_LEN] = 0;
}
else
this->device[0] = 0;
fd = tun_open(this->device);
if (fd == -1)
throw Exception("could not create tunnel device");
char cmdline[512];
snprintf(cmdline, sizeof(cmdline), "/sbin/ifconfig %s mtu %u", this->device, mtu);
if (system(cmdline) != 0)
syslog(LOG_ERR, "could not set tun device mtu");
}
Tun::~Tun()
{
tun_close(fd, device);
}
void Tun::setIp(uint32_t ip, uint32_t destIp, bool includeSubnet)
{
char cmdline[512];
string ips = Utility::formatIp(ip);
string destIps = Utility::formatIp(destIp);
#ifdef LINUX
snprintf(cmdline, sizeof(cmdline), "/sbin/ifconfig %s %s netmask 255.255.255.0", device, ips.c_str());
#else
snprintf(cmdline, sizeof(cmdline), "/sbin/ifconfig %s %s %s netmask 255.255.255.255", device, ips.c_str(), destIps.c_str());
#endif
if (system(cmdline) != 0)
syslog(LOG_ERR, "could not set tun device ip address");
#ifndef LINUX
if (includeSubnet)
{
snprintf(cmdline, sizeof(cmdline), "/sbin/route add %s/24 %s", destIps.c_str(), destIps.c_str());
if (system(cmdline) != 0)
syslog(LOG_ERR, "could not add route");
}
#endif
}
void Tun::write(const char *buffer, int length)
{
if (tun_write(fd, (char *)buffer, length) == -1)
syslog(LOG_ERR, "error writing %d bytes to tun: %s", length, strerror(errno));
}
int Tun::read(char *buffer)
{
int length = tun_read(fd, buffer, mtu);
if (length == -1)
syslog(LOG_ERR, "error reading from tun: %s", strerror(errno));
return length;
}
int Tun::read(char *buffer, uint32_t &sourceIp, uint32_t &destIp)
{
int length = read(buffer);
IpHeader *header = (IpHeader *)buffer;
sourceIp = ntohl(header->ip_src.s_addr);
destIp = ntohl(header->ip_dst.s_addr);
return length;
}