1 /* lint -save -library Flexelint comment for external headers */ 2 3 /*- 4 * Copyright (c) 2001 Charles Mott <cm@linktel.net> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 /*- 32 * Alias.h defines the outside world interfaces for the packet aliasing 33 * software. 34 * 35 * This software is placed into the public domain with no restrictions on its 36 * distribution. 37 */ 38 39 #ifndef _ALIAS_H_ 40 #define _ALIAS_H_ 41 42 /* The external interface to libalias, the packet aliasing engine. */ 43 44 /* Initialization and control functions. */ 45 void PacketAliasInit(void); 46 void PacketAliasSetAddress(struct in_addr _addr); 47 void PacketAliasSetFWBase(unsigned int _base, unsigned int _num); 48 unsigned int 49 PacketAliasSetMode(unsigned int _flags, unsigned int _mask); 50 void PacketAliasUninit(void); 51 52 /* Packet Handling functions. */ 53 int PacketAliasIn(char *_ptr, int _maxpacketsize); 54 int PacketAliasOut(char *_ptr, int _maxpacketsize); 55 int PacketUnaliasOut(char *_ptr, int _maxpacketsize); 56 57 /* Port and address redirection functions. */ 58 59 /* 60 * An anonymous structure, a pointer to which is returned from 61 * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or 62 * PacketAliasRedirectProto(), passed to PacketAliasAddServer(), 63 * and freed by PacketAliasRedirectDelete(). 64 */ 65 struct alias_link; 66 67 int PacketAliasAddServer(struct alias_link *_link, 68 struct in_addr _addr, unsigned short _port); 69 struct alias_link * 70 PacketAliasRedirectAddr(struct in_addr _src_addr, 71 struct in_addr _alias_addr); 72 void PacketAliasRedirectDelete(struct alias_link *_link); 73 struct alias_link * 74 PacketAliasRedirectPort(struct in_addr _src_addr, 75 unsigned short _src_port, struct in_addr _dst_addr, 76 unsigned short _dst_port, struct in_addr _alias_addr, 77 unsigned short _alias_port, unsigned char _proto); 78 struct alias_link * 79 PacketAliasRedirectProto(struct in_addr _src_addr, 80 struct in_addr _dst_addr, struct in_addr _alias_addr, 81 unsigned char _proto); 82 83 /* Fragment Handling functions. */ 84 void PacketAliasFragmentIn(char *_ptr, char *_ptr_fragment); 85 char *PacketAliasGetFragment(char *_ptr); 86 int PacketAliasSaveFragment(char *_ptr); 87 88 /* Miscellaneous functions. */ 89 int PacketAliasCheckNewLink(void); 90 unsigned short 91 PacketAliasInternetChecksum(unsigned short *_ptr, int _nbytes); 92 void PacketAliasSetTarget(struct in_addr _target_addr); 93 94 /* Transparent proxying routines. */ 95 int PacketAliasProxyRule(const char *_cmd); 96 97 /* Mode flags, set using PacketAliasSetMode() */ 98 99 /* 100 * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log 101 * every time a link is created or deleted. This is useful for debugging. 102 */ 103 #define PKT_ALIAS_LOG 0x01 104 105 /* 106 * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp, 107 * telnet or web servers will be prevented by the aliasing mechanism. 108 */ 109 #define PKT_ALIAS_DENY_INCOMING 0x02 110 111 /* 112 * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the 113 * same port as they originated on. This allows e.g. rsh to work *99% of the 114 * time*, but _not_ 100% (it will be slightly flakey instead of not working 115 * at all). This mode bit is set by PacketAliasInit(), so it is a default 116 * mode of operation. 117 */ 118 #define PKT_ALIAS_SAME_PORTS 0x04 119 120 /* 121 * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g. 122 * destination port and/or address is zero), the packet aliasing engine will 123 * attempt to allocate a socket for the aliasing port it chooses. This will 124 * avoid interference with the host machine. Fully specified links do not 125 * require this. This bit is set after a call to PacketAliasInit(), so it is 126 * a default mode of operation. 127 */ 128 #define PKT_ALIAS_USE_SOCKETS 0x08 129 130 /*- 131 * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with 132 * unregistered source addresses will be aliased. Private 133 * addresses are those in the following ranges: 134 * 135 * 10.0.0.0 -> 10.255.255.255 136 * 172.16.0.0 -> 172.31.255.255 137 * 192.168.0.0 -> 192.168.255.255 138 */ 139 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10 140 141 /* 142 * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic 143 * aliasing links will be reset whenever PacketAliasSetAddress() changes the 144 * default aliasing address. If the default aliasing address is left 145 * unchanged by this function call, then the table of dynamic aliasing links 146 * will be left intact. This bit is set after a call to PacketAliasInit(). 147 */ 148 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20 149 150 #ifndef NO_FW_PUNCH 151 /* 152 * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will 153 * create a 'hole' in the firewall to allow the transfers to work. The 154 * ipfw rule number that the hole is created with is controlled by 155 * PacketAliasSetFWBase(). The hole will be attached to that 156 * particular alias_link, so when the link goes away the hole is deleted. 157 */ 158 #define PKT_ALIAS_PUNCH_FW 0x100 159 #endif 160 161 /* 162 * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only 163 * transparent proxying is performed. 164 */ 165 #define PKT_ALIAS_PROXY_ONLY 0x40 166 167 /* 168 * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and 169 * PacketAliasOut() are reversed. 170 */ 171 #define PKT_ALIAS_REVERSE 0x80 172 173 /* Function return codes. */ 174 #define PKT_ALIAS_ERROR -1 175 #define PKT_ALIAS_OK 1 176 #define PKT_ALIAS_IGNORED 2 177 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3 178 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4 179 180 #endif /* !_ALIAS_H_ */ 181 182 /* lint -restore */ 183