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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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* Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
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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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* 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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* 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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/* OCC_STRING_SIZE must be set to sizeof (occ_magic) */
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#define OCC_STRING_SIZE 16
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* OCC (OpenVPN Configuration Control) protocol opcodes.
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#define OCC_REQUEST 0 /* request options string from peer */
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#define OCC_REPLY 1 /* deliver options string to peer */
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* Send an OCC_REQUEST once every OCC_INTERVAL
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* seconds until a reply is received.
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* If we haven't received a reply after
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* OCC_N_TRIES, give up.
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#define OCC_INTERVAL_SECONDS 10
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#define OCC_N_TRIES 12
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* Other OCC protocol opcodes used to estimate the MTU empirically.
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#define OCC_MTU_LOAD_REQUEST 2 /* Ask peer to send a big packet to us */
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#define OCC_MTU_LOAD 3 /* Send a big packet to peer */
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#define OCC_MTU_REQUEST 4 /* Ask peer to tell us the largest
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packet it has received from us so far */
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#define OCC_MTU_REPLY 5 /* Send largest packet size to peer */
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* Process one command from mtu_load_test_sequence
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* once every n seconds, if --mtu-test is specified.
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#define OCC_MTU_LOAD_INTERVAL_SECONDS 3
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* Send an exit message to remote.
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* Used to conduct a load test command sequence
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* of UDP connection for empirical MTU measurement.
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int op; /* OCC opcode to send to peer */
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int delta; /* determine packet size to send by using
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this delta against currently
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extern const uint8_t occ_magic[];
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is_occ_msg (const struct buffer* buf)
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return buf_string_match_head (buf, occ_magic, OCC_STRING_SIZE);
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void process_received_occ_msg (struct context *c);