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 #ifdef _KERNEL 43 /* 44 * The kernel version of libalias does not support these features. 45 */ 46 #define NO_FW_PUNCH 47 #define NO_LOGGING 48 #define NO_USE_SOCKETS 49 #endif 50 51 /* 52 * The external interface to libalias, the packet aliasing engine. 53 * 54 * There are two sets of functions: 55 * 56 * PacketAlias*() the old API which doesn't take an instance pointer 57 * and therefore can only have one packet engine at a time. 58 * 59 * LibAlias*() the new API which takes as first argument a pointer to 60 * the instance of the packet aliasing engine. 61 * 62 * The functions otherwise correspond to each other one for one, except 63 * for the LibAliasUnaliasOut()/PacketUnaliasOut() function which were 64 * were misnamed in the old API. 65 */ 66 67 /* 68 * The instance structure 69 */ 70 struct libalias; 71 72 /* 73 * An anonymous structure, a pointer to which is returned from 74 * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or 75 * PacketAliasRedirectProto(), passed to PacketAliasAddServer(), 76 * and freed by PacketAliasRedirectDelete(). 77 */ 78 struct alias_link; 79 80 81 /* OLD API */ 82 83 /* Initialization and control functions. */ 84 void PacketAliasInit(void); 85 void PacketAliasSetAddress(struct in_addr _addr); 86 void PacketAliasSetFWBase(unsigned int _base, unsigned int _num); 87 void PacketAliasSetSkinnyPort(unsigned int _port); 88 unsigned int 89 PacketAliasSetMode(unsigned int _flags, unsigned int _mask); 90 void PacketAliasUninit(void); 91 92 /* Packet Handling functions. */ 93 int PacketAliasIn(char *_ptr, int _maxpacketsize); 94 int PacketAliasOut(char *_ptr, int _maxpacketsize); 95 int PacketUnaliasOut(char *_ptr, int _maxpacketsize); 96 97 /* Port and address redirection functions. */ 98 99 100 int 101 PacketAliasAddServer(struct alias_link *_lnk, 102 struct in_addr _addr, unsigned short _port); 103 struct alias_link * 104 PacketAliasRedirectAddr(struct in_addr _src_addr, 105 struct in_addr _alias_addr); 106 int PacketAliasRedirectDynamic(struct alias_link *_lnk); 107 void PacketAliasRedirectDelete(struct alias_link *_lnk); 108 struct alias_link * 109 PacketAliasRedirectPort(struct in_addr _src_addr, 110 unsigned short _src_port, struct in_addr _dst_addr, 111 unsigned short _dst_port, struct in_addr _alias_addr, 112 unsigned short _alias_port, unsigned char _proto); 113 struct alias_link * 114 PacketAliasRedirectProto(struct in_addr _src_addr, 115 struct in_addr _dst_addr, struct in_addr _alias_addr, 116 unsigned char _proto); 117 118 /* Fragment Handling functions. */ 119 void PacketAliasFragmentIn(char *_ptr, char *_ptr_fragment); 120 char *PacketAliasGetFragment(char *_ptr); 121 int PacketAliasSaveFragment(char *_ptr); 122 123 /* Miscellaneous functions. */ 124 int PacketAliasCheckNewLink(void); 125 unsigned short 126 PacketAliasInternetChecksum(unsigned short *_ptr, int _nbytes); 127 void PacketAliasSetTarget(struct in_addr _target_addr); 128 129 /* Transparent proxying routines. */ 130 int PacketAliasProxyRule(const char *_cmd); 131 132 /* NEW API */ 133 134 /* Initialization and control functions. */ 135 struct libalias *LibAliasInit(struct libalias *); 136 void LibAliasSetAddress(struct libalias *, struct in_addr _addr); 137 void LibAliasSetFWBase(struct libalias *, unsigned int _base, unsigned int _num); 138 void LibAliasSetSkinnyPort(struct libalias *, unsigned int _port); 139 unsigned int 140 LibAliasSetMode(struct libalias *, unsigned int _flags, unsigned int _mask); 141 void LibAliasUninit(struct libalias *); 142 143 /* Packet Handling functions. */ 144 int LibAliasIn (struct libalias *, char *_ptr, int _maxpacketsize); 145 int LibAliasOut(struct libalias *, char *_ptr, int _maxpacketsize); 146 int LibAliasOutTry(struct libalias *, char *_ptr, int _maxpacketsize, int _create); 147 int LibAliasUnaliasOut(struct libalias *, char *_ptr, int _maxpacketsize); 148 149 /* Port and address redirection functions. */ 150 151 int 152 LibAliasAddServer(struct libalias *, struct alias_link *_lnk, 153 struct in_addr _addr, unsigned short _port); 154 struct alias_link * 155 LibAliasRedirectAddr(struct libalias *, struct in_addr _src_addr, 156 struct in_addr _alias_addr); 157 int LibAliasRedirectDynamic(struct libalias *, struct alias_link *_lnk); 158 void LibAliasRedirectDelete(struct libalias *, struct alias_link *_lnk); 159 struct alias_link * 160 LibAliasRedirectPort(struct libalias *, struct in_addr _src_addr, 161 unsigned short _src_port, struct in_addr _dst_addr, 162 unsigned short _dst_port, struct in_addr _alias_addr, 163 unsigned short _alias_port, unsigned char _proto); 164 struct alias_link * 165 LibAliasRedirectProto(struct libalias *, struct in_addr _src_addr, 166 struct in_addr _dst_addr, struct in_addr _alias_addr, 167 unsigned char _proto); 168 169 /* Fragment Handling functions. */ 170 void LibAliasFragmentIn(struct libalias *, char *_ptr, char *_ptr_fragment); 171 char *LibAliasGetFragment(struct libalias *, char *_ptr); 172 int LibAliasSaveFragment(struct libalias *, char *_ptr); 173 174 /* Miscellaneous functions. */ 175 int LibAliasCheckNewLink(struct libalias *); 176 unsigned short 177 LibAliasInternetChecksum(struct libalias *, unsigned short *_ptr, int _nbytes); 178 void LibAliasSetTarget(struct libalias *, struct in_addr _target_addr); 179 180 /* Transparent proxying routines. */ 181 int LibAliasProxyRule(struct libalias *, const char *_cmd); 182 183 184 /* 185 * Mode flags and other constants. 186 */ 187 188 189 /* Mode flags, set using PacketAliasSetMode() */ 190 191 /* 192 * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log 193 * every time a link is created or deleted. This is useful for debugging. 194 */ 195 #ifndef NO_LOGGING 196 #define PKT_ALIAS_LOG 0x01 197 #endif 198 199 /* 200 * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp, 201 * telnet or web servers will be prevented by the aliasing mechanism. 202 */ 203 #define PKT_ALIAS_DENY_INCOMING 0x02 204 205 /* 206 * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the 207 * same port as they originated on. This allows e.g. rsh to work *99% of the 208 * time*, but _not_ 100% (it will be slightly flakey instead of not working 209 * at all). This mode bit is set by PacketAliasInit(), so it is a default 210 * mode of operation. 211 */ 212 #define PKT_ALIAS_SAME_PORTS 0x04 213 214 /* 215 * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g. 216 * destination port and/or address is zero), the packet aliasing engine will 217 * attempt to allocate a socket for the aliasing port it chooses. This will 218 * avoid interference with the host machine. Fully specified links do not 219 * require this. This bit is set after a call to PacketAliasInit(), so it is 220 * a default mode of operation. 221 */ 222 #ifndef NO_USE_SOCKETS 223 #define PKT_ALIAS_USE_SOCKETS 0x08 224 #endif 225 /*- 226 * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with 227 * unregistered source addresses will be aliased. Private 228 * addresses are those in the following ranges: 229 * 230 * 10.0.0.0 -> 10.255.255.255 231 * 172.16.0.0 -> 172.31.255.255 232 * 192.168.0.0 -> 192.168.255.255 233 */ 234 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10 235 236 /* 237 * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic 238 * aliasing links will be reset whenever PacketAliasSetAddress() changes the 239 * default aliasing address. If the default aliasing address is left 240 * unchanged by this function call, then the table of dynamic aliasing links 241 * will be left intact. This bit is set after a call to PacketAliasInit(). 242 */ 243 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20 244 245 #ifndef NO_FW_PUNCH 246 /* 247 * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will 248 * create a 'hole' in the firewall to allow the transfers to work. The 249 * ipfw rule number that the hole is created with is controlled by 250 * PacketAliasSetFWBase(). The hole will be attached to that 251 * particular alias_link, so when the link goes away the hole is deleted. 252 */ 253 #define PKT_ALIAS_PUNCH_FW 0x100 254 #endif 255 256 /* 257 * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only 258 * transparent proxying is performed. 259 */ 260 #define PKT_ALIAS_PROXY_ONLY 0x40 261 262 /* 263 * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and 264 * PacketAliasOut() are reversed. 265 */ 266 #define PKT_ALIAS_REVERSE 0x80 267 268 /* Function return codes. */ 269 #define PKT_ALIAS_ERROR -1 270 #define PKT_ALIAS_OK 1 271 #define PKT_ALIAS_IGNORED 2 272 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3 273 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4 274 275 #endif /* !_ALIAS_H_ */ 276 277 /* lint -restore */ 278