/*
    device.c -- Interaction with MacOS/X tun device
    Copyright (C) 2001-2002 Ivo Timmermans <ivo@o2w.nl>,
                  2001-2002 Guus Sliepen <guus@sliepen.eu.org>

    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 2 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, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    $Id: device.c,v 1.1.2.4 2002/09/09 22:33:23 guus Exp $
*/

#include "config.h"

#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <fcntl.h>
#include <net/if.h>
#include <unistd.h>
#include <syslog.h>
#include <string.h>

#include <utils.h>
#include "conf.h"
#include "net.h"
#include "subnet.h"

#include "system.h"

#define DEFAULT_DEVICE "/dev/tun0"

int device_fd = -1;
int device_type;
char *device;
char *interface;
char *device_info;
int device_total_in = 0;
int device_total_out = 0;

extern subnet_t mymac;

/*
  open the local ethertap device
*/
int setup_device(void)
{
	cp if(!get_config_string(lookup_config(config_tree, "Device"), &device))
		device = DEFAULT_DEVICE;

	if(!get_config_string(lookup_config(config_tree, "Interface"), &interface))
		interface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
	cp if((device_fd = open(device, O_RDWR | O_NONBLOCK)) < 0) {
		syslog(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
		return -1;
	}
	cp
		/* Set default MAC address for ethertap devices */
		mymac.type = SUBNET_MAC;
	mymac.net.mac.address.x[0] = 0xfe;
	mymac.net.mac.address.x[1] = 0xfd;
	mymac.net.mac.address.x[2] = 0x00;
	mymac.net.mac.address.x[3] = 0x00;
	mymac.net.mac.address.x[4] = 0x00;
	mymac.net.mac.address.x[5] = 0x00;

	device_info = _("MacOS/X tun device");

	syslog(LOG_INFO, _("%s is a %s"), device, device_info);
	cp return 0;
}

void close_device(void)
{
	cp close(device_fd);
}

/*
  read, encrypt and send data that is
  available through the ethertap device
*/
int read_packet(vpn_packet_t *packet)
{
	int lenin;
	cp if((lenin = read(device_fd, packet->data + 14, MTU - 14)) <= 0) {
		syslog(LOG_ERR, _("Error while reading from %s %s: %s"), device_info,
			   device, strerror(errno));
		return -1;
	}

	memcpy(packet->data, mymac.net.mac.address.x, 6);
	memcpy(packet->data + 6, mymac.net.mac.address.x, 6);
	packet->data[12] = 0x08;
	packet->data[13] = 0x00;

	packet->len = lenin + 14;

	device_total_in += packet->len;

	if(debug_lvl >= DEBUG_TRAFFIC)
		syslog(LOG_DEBUG, _("Read packet of %d bytes from %s"),
			   packet->len, device_info);

	return 0;
cp}

int write_packet(vpn_packet_t *packet)
{
	cp if(debug_lvl >= DEBUG_TRAFFIC)
		syslog(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
			   packet->len, device_info);

	if(write(device_fd, packet->data + 14, packet->len - 14) < 0) {
		syslog(LOG_ERR, _("Error while writing to %s %s: %s"), device_info,
			   device, strerror(errno));
		return -1;
	}

	device_total_out += packet->len;
cp}

void dump_device_stats(void)
{
	cp syslog(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
	syslog(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
	syslog(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
cp}