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/*
* uAnytun
*
* uAnytun is a tiny implementation of SATP. Unlike Anytun which is a full
* featured implementation uAnytun has no support for multiple connections
* or synchronisation. It is a small single threaded implementation intended
* to act as a client on small platforms.
* The secure anycast tunneling protocol (satp) defines a protocol used
* for communication between any combination of unicast and anycast
* tunnel endpoints. It has less protocol overhead than IPSec in Tunnel
* mode and allows tunneling of every ETHER TYPE protocol (e.g.
* ethernet, ip, arp ...). satp directly includes cryptography and
* message authentication based on the methods used by SRTP. It is
* intended to deliver a generic, scaleable and secure solution for
* tunneling and relaying of packets of any protocol.
*
*
* Copyright (C) 2007-2014 Christian Pointner <equinox@anytun.org>
*
* This file is part of uAnytun.
*
* uAnytun 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
* any later version.
*
* uAnytun 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 uAnytun. If not, see <http://www.gnu.org/licenses/>.
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include "datatypes.h"
#include "tun.h"
#include "tun_helper.h"
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <errno.h>
#include <net/if.h>
#include <linux/ip.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#define DEFAULT_DEVICE "/dev/net/tun"
#include "log.h"
#include "sysexec.h"
int tun_init(tun_device_t* dev, const char* dev_name, const char* dev_type, const char* ifcfg_addr, u_int16_t ifcfg_prefix){
if(!dev)
return -1;
tun_conf(dev, dev_name, dev_type, ifcfg_addr, ifcfg_prefix, 1400);
dev->actual_name_ = NULL;
dev->fd_ = open(DEFAULT_DEVICE, O_RDWR);
if(dev->fd_ < 0) {
log_printf(ERROR, "can't open device file (%s): %s", DEFAULT_DEVICE, strerror(errno));
tun_close(dev);
return -1;
}
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
if(dev->type_ == TYPE_TUN) {
ifr.ifr_flags = IFF_TUN;
dev->with_pi_ = 1;
}
else if(dev->type_ == TYPE_TAP) {
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
dev->with_pi_ = 0;
}
else {
log_printf(ERROR, "unable to recognize type of device (tun or tap)");
tun_close(dev);
return -1;
}
if(dev_name)
strncpy(ifr.ifr_name, dev_name, IFNAMSIZ-1);
if(!ioctl(dev->fd_, TUNSETIFF, &ifr)) {
dev->actual_name_ = strdup(ifr.ifr_name);
} else if(!ioctl(dev->fd_, (('T' << 8) | 202), &ifr)) {
dev->actual_name_ = strdup(ifr.ifr_name);
} else {
log_printf(ERROR, "tun/tap device ioctl failed: %s", strerror(errno));
tun_close(dev);
return -1;
}
if(!dev->actual_name_) {
log_printf(ERROR, "can't open device file: memory error");
tun_close(dev);
return -2;
}
if(ifcfg_addr)
tun_do_ifconfig(dev);
return 0;
}
int tun_init_post(tun_device_t* dev)
{
// nothing yet
return 0;
}
void tun_close(tun_device_t* dev)
{
if(!dev)
return;
if(dev->fd_ > 0)
close(dev->fd_);
if(dev->actual_name_)
free(dev->actual_name_);
if(dev->net_addr_)
free(dev->net_addr_);
if(dev->net_mask_)
free(dev->net_mask_);
}
int tun_read(tun_device_t* dev, u_int8_t* buf, u_int32_t len)
{
if(!dev || dev->fd_ < 0)
return -1;
if(dev->with_pi_)
{
struct iovec iov[2];
struct tun_pi tpi;
iov[0].iov_base = &tpi;
iov[0].iov_len = sizeof(tpi);
iov[1].iov_base = buf;
iov[1].iov_len = len;
return(tun_fix_return(readv(dev->fd_, iov, 2), sizeof(tpi)));
}
else
return(read(dev->fd_, buf, len));
}
int tun_write(tun_device_t* dev, u_int8_t* buf, u_int32_t len)
{
if(!dev || dev->fd_ < 0)
return -1;
if(!buf)
return 0;
if(dev->with_pi_)
{
struct iovec iov[2];
struct tun_pi tpi;
struct iphdr *hdr = (struct iphdr *)buf;
tpi.flags = 0;
if(hdr->version == 4)
tpi.proto = htons(ETH_P_IP);
else
tpi.proto = htons(ETH_P_IPV6);
iov[0].iov_base = &tpi;
iov[0].iov_len = sizeof(tpi);
iov[1].iov_base = buf;
iov[1].iov_len = len;
return(tun_fix_return(writev(dev->fd_, iov, 2), sizeof(tpi)));
}
else
return(write(dev->fd_, buf, len));
}
void tun_do_ifconfig(tun_device_t* dev)
{
if(!dev || !dev->actual_name_ || !dev->net_addr_ || !dev->net_mask_)
return;
char* mtu_str = NULL;
int len = asprintf(&mtu_str, "%d", dev->mtu_);
if(len == -1) {
log_printf(ERROR, "Execution of ifconfig failed");
return;
}
char* const argv[] = { "/sbin/ifconfig", dev->actual_name_, dev->net_addr_, "netmask", dev->net_mask_, "mtu", mtu_str, NULL };
char* const evp[] = { NULL };
uanytun_exec("/sbin/ifconfig", argv, evp);
free(mtu_str);
}
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