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/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* 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 (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifdef WIN32
#include "config-win32.h"
#else
#include "config.h"
#endif
#include "syshead.h"
#include "proto.h"
#include "memdbg.h"
/*
* If raw tunnel packet is IPv4, return true and increment
* buffer offset to start of IP header.
*/
bool
is_ipv4 (int tunnel_type, struct buffer *buf)
{
int offset;
const struct openvpn_iphdr *ih;
verify_align_4 (buf);
if (tunnel_type == DEV_TYPE_TUN)
{
if (BLEN (buf) < (int) sizeof (struct openvpn_iphdr))
return false;
offset = 0;
}
else if (tunnel_type == DEV_TYPE_TAP)
{
const struct openvpn_ethhdr *eh;
if (BLEN (buf) < (int)(sizeof (struct openvpn_ethhdr)
+ sizeof (struct openvpn_iphdr)))
return false;
eh = (const struct openvpn_ethhdr *) BPTR (buf);
if (ntohs (eh->proto) != OPENVPN_ETH_P_IPV4)
return false;
offset = sizeof (struct openvpn_ethhdr);
}
else
return false;
ih = (const struct openvpn_iphdr *) (BPTR (buf) + offset);
if (OPENVPN_IPH_GET_VER (ih->version_len) == 4)
return buf_advance (buf, offset);
else
return false;
}
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