mirror of
https://github.com/OpenVPN/openvpn.git
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3c7f2f553b
git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@581 e7ae566f-a301-0410-adde-c780ea21d3b5
129 lines
3.2 KiB
C
129 lines
3.2 KiB
C
/*
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* OpenVPN -- An application to securely tunnel IP networks
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* over a single TCP/UDP port, with support for SSL/TLS-based
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* session authentication and key exchange,
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* packet encryption, packet authentication, and
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* packet compression.
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*
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* Copyright (C) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program (see the file COPYING included with this
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* distribution); if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifdef WIN32
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#include "config-win32.h"
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#else
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#include "config.h"
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#endif
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#include "syshead.h"
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#include "proto.h"
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#include "error.h"
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#include "memdbg.h"
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/*
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* If raw tunnel packet is IPv4, return true and increment
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* buffer offset to start of IP header.
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*/
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bool
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is_ipv4 (int tunnel_type, struct buffer *buf)
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{
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int offset;
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const struct openvpn_iphdr *ih;
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verify_align_4 (buf);
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if (tunnel_type == DEV_TYPE_TUN)
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{
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if (BLEN (buf) < (int) sizeof (struct openvpn_iphdr))
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return false;
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offset = 0;
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}
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else if (tunnel_type == DEV_TYPE_TAP)
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{
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const struct openvpn_ethhdr *eh;
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if (BLEN (buf) < (int)(sizeof (struct openvpn_ethhdr)
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+ sizeof (struct openvpn_iphdr)))
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return false;
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eh = (const struct openvpn_ethhdr *) BPTR (buf);
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if (ntohs (eh->proto) != OPENVPN_ETH_P_IPV4)
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return false;
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offset = sizeof (struct openvpn_ethhdr);
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}
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else
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return false;
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ih = (const struct openvpn_iphdr *) (BPTR (buf) + offset);
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if (OPENVPN_IPH_GET_VER (ih->version_len) == 4)
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return buf_advance (buf, offset);
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else
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return false;
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}
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#ifdef PACKET_TRUNCATION_CHECK
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void
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ipv4_packet_size_verify (const uint8_t *data,
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const int size,
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const int tunnel_type,
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const char *prefix,
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counter_type *errors)
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{
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if (size > 0)
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{
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struct buffer buf;
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buf_set_read (&buf, data, size);
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if (is_ipv4 (tunnel_type, &buf))
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{
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const struct openvpn_iphdr *pip;
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int hlen;
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int totlen;
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const char *msgstr = "PACKET SIZE INFO";
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unsigned int msglevel = D_PACKET_TRUNC_DEBUG;
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if (BLEN (&buf) < (int) sizeof (struct openvpn_iphdr))
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return;
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verify_align_4 (&buf);
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pip = (struct openvpn_iphdr *) BPTR (&buf);
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hlen = OPENVPN_IPH_GET_LEN (pip->version_len);
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totlen = ntohs (pip->tot_len);
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if (BLEN (&buf) != totlen)
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{
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msgstr = "PACKET TRUNCATION ERROR";
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msglevel = D_PACKET_TRUNC_ERR;
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if (errors)
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++(*errors);
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}
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msg (msglevel, "%s %s: size=%d totlen=%d hlen=%d errcount=" counter_format,
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msgstr,
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prefix,
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BLEN (&buf),
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totlen,
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hlen,
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errors ? *errors : (counter_type)0);
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}
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}
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}
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#endif
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