1/* 2 * OpenVPN -- An application to securely tunnel IP networks 3 * over a single TCP/UDP port, with support for SSL/TLS-based 4 * session authentication and key exchange, 5 * packet encryption, packet authentication, and 6 * packet compression. 7 * 8 * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 12 * as published by the Free Software Foundation. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program (see the file COPYING included with this 21 * distribution); if not, write to the Free Software Foundation, Inc., 22 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 23 */ 24 25#ifndef OCC_H 26#define OCC_H 27 28#ifdef ENABLE_OCC 29 30#include "forward.h" 31 32/* OCC_STRING_SIZE must be set to sizeof (occ_magic) */ 33#define OCC_STRING_SIZE 16 34 35/* 36 * OCC (OpenVPN Configuration Control) protocol opcodes. 37 */ 38 39#define OCC_REQUEST 0 /* request options string from peer */ 40#define OCC_REPLY 1 /* deliver options string to peer */ 41 42/* 43 * Send an OCC_REQUEST once every OCC_INTERVAL 44 * seconds until a reply is received. 45 * 46 * If we haven't received a reply after 47 * OCC_N_TRIES, give up. 48 */ 49#define OCC_INTERVAL_SECONDS 10 50#define OCC_N_TRIES 12 51 52/* 53 * Other OCC protocol opcodes used to estimate the MTU empirically. 54 */ 55#define OCC_MTU_LOAD_REQUEST 2 /* Ask peer to send a big packet to us */ 56#define OCC_MTU_LOAD 3 /* Send a big packet to peer */ 57#define OCC_MTU_REQUEST 4 /* Ask peer to tell us the largest 58 packet it has received from us so far */ 59#define OCC_MTU_REPLY 5 /* Send largest packet size to peer */ 60 61/* 62 * Process one command from mtu_load_test_sequence 63 * once every n seconds, if --mtu-test is specified. 64 */ 65#define OCC_MTU_LOAD_INTERVAL_SECONDS 3 66 67/* 68 * Send an exit message to remote. 69 */ 70#define OCC_EXIT 6 71 72/* 73 * Used to conduct a load test command sequence 74 * of UDP connection for empirical MTU measurement. 75 */ 76struct mtu_load_test 77{ 78 int op; /* OCC opcode to send to peer */ 79 int delta; /* determine packet size to send by using 80 this delta against currently 81 configured MTU */ 82}; 83 84extern const uint8_t occ_magic[]; 85 86static inline bool 87is_occ_msg (const struct buffer* buf) 88{ 89 return buf_string_match_head (buf, occ_magic, OCC_STRING_SIZE); 90} 91 92void process_received_occ_msg (struct context *c); 93 94#endif 95#endif 96