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tun_darwin.c
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tun_darwin.c
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/* $Id$ */
/*
* Copyright (c) 2012 KAMADA Ken'ichi.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/kern_control.h>
#include <sys/socket.h>
#include <sys/sys_domain.h>
#include <arpa/inet.h>
#include <net/if_utun.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "var.h"
#include "util.h"
#include "tun_if.h"
#define TUN_HEAD_LEN 4 /* TUNSIFHEAD */
int
open_tun(const char *devarg)
{
struct sockaddr_ctl sc;
struct ctl_info ci;
unsigned int unit_num;
int fd;
/* XXX overflow */
if (sscanf(devarg, "utun%u", &unit_num) != 1) {
LERR("%s: invalid utun device name", devarg);
return -1;
}
memset(&ci, 0, sizeof(ci));
if (strlcpy(ci.ctl_name, UTUN_CONTROL_NAME, sizeof(ci.ctl_name)) >=
sizeof(ci.ctl_name)) {
LERR("UTUN_CONTROL_NAME too long");
return -1;
}
if ((fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL)) == -1) {
LERR("socket(SYSPROTO_CONTROL): %s", strerror(errno));
return -1;
}
if (ioctl(fd, CTLIOCGINFO, &ci) == -1) {
LERR("ioctl(CTLIOCGINFO): %s", strerror(errno));
close(fd);
return -1;
}
memset(&sc, 0, sizeof(sc));
sc.sc_len = sizeof(sc);
sc.sc_family = AF_SYSTEM;
sc.ss_sysaddr = AF_SYS_CONTROL;
sc.sc_id = ci.ctl_id;
sc.sc_unit = unit_num + 1; /* zero means unspecified */
if (connect(fd, (struct sockaddr *)&sc, sizeof(sc)) == -1) {
LERR("connect(AF_SYS_CONTROL): %s", strerror(errno));
close(fd);
return -1;
}
return fd;
}
size_t
check_tun_header(const char *buf, size_t len)
{
unsigned long family;
if (len < TUN_HEAD_LEN) {
LDEBUG("tun: no address family");
return -1;
}
if ((family = ntohl(*(const uint32_t *)buf)) != AF_INET6) {
LDEBUG("tun: non-IPv6 packet (%lu)", family);
return -1;
}
return TUN_HEAD_LEN;
}
size_t
add_tun_header(char *buf, size_t space)
{
if (space < TUN_HEAD_LEN) {
LDEBUG("tun: no space for address family");
return -1;
}
*(uint32_t *)(buf - TUN_HEAD_LEN) = htonl(AF_INET6);
return TUN_HEAD_LEN;
}