iodine/tun.c

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/*
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* Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>, Erik Ekman <yarrick@kryo.se>
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*
* 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>
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#include <stdlib.h>
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#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <stdint.h>
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#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <err.h>
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include "tun.h"
#define TUN_MAX_TRY 50
char *tun_device = NULL;
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char if_name[50];
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#ifdef LINUX
#include <sys/ioctl.h>
#include <net/if.h>
#include <linux/if_tun.h>
int
open_tun()
{
int i;
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int tun_fd;
struct ifreq ifreq;
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if (tun_device == NULL)
tun_device = "/dev/net/tun";
if ((tun_fd = open(tun_device, O_RDWR)) < 0) {
warn("open_tun: %s: %s", tun_device, strerror(errno));
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return -1;
}
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bzero(&ifreq, sizeof(ifreq));
ifreq.ifr_flags = IFF_TUN;
for (i = 0; i < TUN_MAX_TRY; i++) {
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snprintf(ifreq.ifr_name, IFNAMSIZ, "dns%d", i);
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if (ioctl(tun_fd, TUNSETIFF, (void *) &ifreq) != -1) {
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printf("Opened %s\n", ifreq.ifr_name);
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snprintf(if_name, sizeof(if_name), "dns%d", i);
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return tun_fd;
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}
if (errno != EBUSY) {
warn("open_tun: ioctl[TUNSETIFF]: %s", strerror(errno));
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return -1;
}
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}
warn("open_tun: Couldn't set interface name.\n");
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return -1;
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}
#else /* BSD */
int
open_tun()
{
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int i;
int tun_fd;
char tun_name[50];
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if (tun_device != NULL) {
if ((tun_fd = open(tun_device, O_RDWR)) < 0) {
warn("open_tun: %s: %s", tun_device, strerror(errno));
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return -1;
}
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} else {
for (i = 0; i < TUN_MAX_TRY; i++) {
snprintf(tun_name, sizeof(tun_name), "/dev/tun%d", i);
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if ((tun_fd = open(tun_name, O_RDWR)) >= 0) {
printf("Opened %s\n", tun_name);
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snprintf(if_name, sizeof(if_name), "tun%d", i);
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return tun_fd;
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}
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if (errno == ENOENT)
break;
}
warn("open_tun: Failed to open tunneling device.");
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}
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return -1;
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}
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#endif /* !LINUX */
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void
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close_tun(int tun_fd)
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{
if (tun_fd >= 0)
close(tun_fd);
}
int
write_tun(int tun_fd, char *data, int len)
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{
#ifdef LINUX
data[0] = 0x00;
data[1] = 0x00;
data[2] = 0x08;
data[3] = 0x00;
#else /* LINUX */
data[0] = 0x00;
data[1] = 0x00;
data[2] = 0x00;
data[3] = 0x02;
#endif /* !LINUX */
if (write(tun_fd, data, len) != len) {
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warn("write_tun");
return 1;
}
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return 0;
}
int
read_tun(int tun_fd, char *buf, int len)
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{
return read(tun_fd, buf, len);
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}
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int
tun_setip(const char *ip)
{
char cmdline[512];
if (inet_addr(ip) != INADDR_NONE) {
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snprintf(cmdline, sizeof(cmdline),
"/sbin/ifconfig %s %s netmask 255.255.255.0",
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if_name,
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ip);
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printf("Setting IP of %s to %s\n", if_name, ip);
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#ifndef LINUX
int r;
r = system(cmdline);
if(r != 0) {
return r;
} else {
snprintf(cmdline, sizeof(cmdline),
"/sbin/route add %s/24 %s",
ip, ip);
}
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printf("Adding route %s/24 to %s\n", ip, ip);
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#endif
return system(cmdline);
} else {
printf("Invalid IP: %s!\n", ip);
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}
return 1;
}
int
tun_setmtu(const int mtu)
{
char cmdline[512];
if (mtu > 200 && mtu < 1500) {
snprintf(cmdline, sizeof(cmdline),
"/sbin/ifconfig %s mtu %d",
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if_name,
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mtu);
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printf("Setting MTU of %s to %d\n", if_name, mtu);
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return system(cmdline);
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} else {
warn("MTU out of range: %d\n", mtu);
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}
return 1;
}