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 /* 43 * The external interface to libalias, the packet aliasing engine. 44 * 45 * There are two sets of functions: 46 * 47 * PacketAlias*() the old API which doesn't take an instance pointer 48 * and therefore can only have one packet engine at a time. 49 * 50 * LibAlias*() the new API which takes as first argument a pointer to 51 * the instance of the packet aliasing engine. 52 * 53 * The functions otherwise correspond to each other one for one, except 54 * for the LibAliasUnaliasOut()/PacketUnaliasOut() function which were 55 * were misnamed in the old API. 56 */ 57 58 /* 59 * The instance structure 60 */ 61 struct libalias; 62 63 /* 64 * An anonymous structure, a pointer to which is returned from 65 * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or 66 * PacketAliasRedirectProto(), passed to PacketAliasAddServer(), 67 * and freed by PacketAliasRedirectDelete(). 68 */ 69 struct alias_link; 70 71 72 /* OLD API */ 73 74 /* Initialization and control functions. */ 75 void PacketAliasInit(void); 76 void PacketAliasSetAddress(struct in_addr _addr); 77 void PacketAliasSetFWBase(unsigned int _base, unsigned int _num); 78 void PacketAliasSetSkinnyPort(unsigned int _port); 79 unsigned int 80 PacketAliasSetMode(unsigned int _flags, unsigned int _mask); 81 void PacketAliasUninit(void); 82 83 /* Packet Handling functions. */ 84 int PacketAliasIn(char *_ptr, int _maxpacketsize); 85 int PacketAliasOut(char *_ptr, int _maxpacketsize); 86 int PacketUnaliasOut(char *_ptr, int _maxpacketsize); 87 88 /* Port and address redirection functions. */ 89 90 91 int PacketAliasAddServer(struct alias_link *_link, 92 struct in_addr _addr, unsigned short _port); 93 struct alias_link * 94 PacketAliasRedirectAddr(struct in_addr _src_addr, 95 struct in_addr _alias_addr); 96 int PacketAliasRedirectDynamic(struct alias_link *_link); 97 void PacketAliasRedirectDelete(struct alias_link *_link); 98 struct alias_link * 99 PacketAliasRedirectPort(struct in_addr _src_addr, 100 unsigned short _src_port, struct in_addr _dst_addr, 101 unsigned short _dst_port, struct in_addr _alias_addr, 102 unsigned short _alias_port, unsigned char _proto); 103 struct alias_link * 104 PacketAliasRedirectProto(struct in_addr _src_addr, 105 struct in_addr _dst_addr, struct in_addr _alias_addr, 106 unsigned char _proto); 107 108 /* Fragment Handling functions. */ 109 void PacketAliasFragmentIn(char *_ptr, char *_ptr_fragment); 110 char *PacketAliasGetFragment(char *_ptr); 111 int PacketAliasSaveFragment(char *_ptr); 112 113 /* Miscellaneous functions. */ 114 int PacketAliasCheckNewLink(void); 115 unsigned short 116 PacketAliasInternetChecksum(unsigned short *_ptr, int _nbytes); 117 void PacketAliasSetTarget(struct in_addr _target_addr); 118 119 /* Transparent proxying routines. */ 120 int PacketAliasProxyRule(const char *_cmd); 121 122 /* NEW API */ 123 124 /* Initialization and control functions. */ 125 struct libalias *LibAliasInit(struct libalias *); 126 void LibAliasSetAddress(struct libalias *, struct in_addr _addr); 127 void LibAliasSetFWBase(struct libalias *, unsigned int _base, unsigned int _num); 128 void LibAliasSetSkinnyPort(struct libalias *, unsigned int _port); 129 unsigned int 130 LibAliasSetMode(struct libalias *, unsigned int _flags, unsigned int _mask); 131 void LibAliasUninit(struct libalias *); 132 133 /* Packet Handling functions. */ 134 int LibAliasIn(struct libalias *, char *_ptr, int _maxpacketsize); 135 int LibAliasOut(struct libalias *, char *_ptr, int _maxpacketsize); 136 int LibAliasUnaliasOut(struct libalias *, char *_ptr, int _maxpacketsize); 137 138 /* Port and address redirection functions. */ 139 140 int LibAliasAddServer(struct libalias *, struct alias_link *_link, 141 struct in_addr _addr, unsigned short _port); 142 struct alias_link * 143 LibAliasRedirectAddr(struct libalias *, struct in_addr _src_addr, 144 struct in_addr _alias_addr); 145 int LibAliasRedirectDynamic(struct libalias *, struct alias_link *_link); 146 void LibAliasRedirectDelete(struct libalias *, struct alias_link *_link); 147 struct alias_link * 148 LibAliasRedirectPort(struct libalias *, struct in_addr _src_addr, 149 unsigned short _src_port, struct in_addr _dst_addr, 150 unsigned short _dst_port, struct in_addr _alias_addr, 151 unsigned short _alias_port, unsigned char _proto); 152 struct alias_link * 153 LibAliasRedirectProto(struct libalias *, struct in_addr _src_addr, 154 struct in_addr _dst_addr, struct in_addr _alias_addr, 155 unsigned char _proto); 156 157 /* Fragment Handling functions. */ 158 void LibAliasFragmentIn(struct libalias *, char *_ptr, char *_ptr_fragment); 159 char *LibAliasGetFragment(struct libalias *, char *_ptr); 160 int LibAliasSaveFragment(struct libalias *, char *_ptr); 161 162 /* Miscellaneous functions. */ 163 int LibAliasCheckNewLink(struct libalias *); 164 unsigned short 165 LibAliasInternetChecksum(struct libalias *, unsigned short *_ptr, int _nbytes); 166 void LibAliasSetTarget(struct libalias *, struct in_addr _target_addr); 167 168 /* Transparent proxying routines. */ 169 int LibAliasProxyRule(struct libalias *, const char *_cmd); 170 171 172 /* 173 * Mode flags and other constants. 174 */ 175 176 177 /* Mode flags, set using PacketAliasSetMode() */ 178 179 /* 180 * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log 181 * every time a link is created or deleted. This is useful for debugging. 182 */ 183 #define PKT_ALIAS_LOG 0x01 184 185 /* 186 * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp, 187 * telnet or web servers will be prevented by the aliasing mechanism. 188 */ 189 #define PKT_ALIAS_DENY_INCOMING 0x02 190 191 /* 192 * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the 193 * same port as they originated on. This allows e.g. rsh to work *99% of the 194 * time*, but _not_ 100% (it will be slightly flakey instead of not working 195 * at all). This mode bit is set by PacketAliasInit(), so it is a default 196 * mode of operation. 197 */ 198 #define PKT_ALIAS_SAME_PORTS 0x04 199 200 /* 201 * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g. 202 * destination port and/or address is zero), the packet aliasing engine will 203 * attempt to allocate a socket for the aliasing port it chooses. This will 204 * avoid interference with the host machine. Fully specified links do not 205 * require this. This bit is set after a call to PacketAliasInit(), so it is 206 * a default mode of operation. 207 */ 208 #define PKT_ALIAS_USE_SOCKETS 0x08 209 210 /*- 211 * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with 212 * unregistered source addresses will be aliased. Private 213 * addresses are those in the following ranges: 214 * 215 * 10.0.0.0 -> 10.255.255.255 216 * 172.16.0.0 -> 172.31.255.255 217 * 192.168.0.0 -> 192.168.255.255 218 */ 219 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10 220 221 /* 222 * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic 223 * aliasing links will be reset whenever PacketAliasSetAddress() changes the 224 * default aliasing address. If the default aliasing address is left 225 * unchanged by this function call, then the table of dynamic aliasing links 226 * will be left intact. This bit is set after a call to PacketAliasInit(). 227 */ 228 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20 229 230 #ifndef NO_FW_PUNCH 231 /* 232 * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will 233 * create a 'hole' in the firewall to allow the transfers to work. The 234 * ipfw rule number that the hole is created with is controlled by 235 * PacketAliasSetFWBase(). The hole will be attached to that 236 * particular alias_link, so when the link goes away the hole is deleted. 237 */ 238 #define PKT_ALIAS_PUNCH_FW 0x100 239 #endif 240 241 /* 242 * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only 243 * transparent proxying is performed. 244 */ 245 #define PKT_ALIAS_PROXY_ONLY 0x40 246 247 /* 248 * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and 249 * PacketAliasOut() are reversed. 250 */ 251 #define PKT_ALIAS_REVERSE 0x80 252 253 /* Function return codes. */ 254 #define PKT_ALIAS_ERROR -1 255 #define PKT_ALIAS_OK 1 256 #define PKT_ALIAS_IGNORED 2 257 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3 258 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4 259 260 #endif /* !_ALIAS_H_ */ 261 262 /* lint -restore */ 263