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 #include <netinet/in_systm.h> 43 #include <netinet/in.h> 44 #include <netinet/ip.h> 45 46 #define LIBALIAS_BUF_SIZE 128 47 #ifdef _KERNEL 48 /* 49 * The kernel version of libalias does not support these features. 50 */ 51 #define NO_FW_PUNCH 52 #define NO_USE_SOCKETS 53 #endif 54 55 /* 56 * The external interface to libalias, the packet aliasing engine. 57 * 58 * There are two sets of functions: 59 * 60 * PacketAlias*() the old API which doesn't take an instance pointer 61 * and therefore can only have one packet engine at a time. 62 * 63 * LibAlias*() the new API which takes as first argument a pointer to 64 * the instance of the packet aliasing engine. 65 * 66 * The functions otherwise correspond to each other one for one, except 67 * for the LibAliasUnaliasOut()/PacketUnaliasOut() function which were 68 * were misnamed in the old API. 69 */ 70 71 /* 72 * The instance structure 73 */ 74 struct libalias; 75 76 /* 77 * An anonymous structure, a pointer to which is returned from 78 * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or 79 * PacketAliasRedirectProto(), passed to PacketAliasAddServer(), 80 * and freed by PacketAliasRedirectDelete(). 81 */ 82 struct alias_link; 83 84 /* Initialization and control functions. */ 85 struct libalias *LibAliasInit(struct libalias *); 86 void LibAliasSetAddress(struct libalias *, struct in_addr _addr); 87 void LibAliasSetFWBase(struct libalias *, unsigned int _base, unsigned int _num); 88 void LibAliasSetSkinnyPort(struct libalias *, unsigned int _port); 89 unsigned int 90 LibAliasSetMode(struct libalias *, unsigned int _flags, unsigned int _mask); 91 void LibAliasUninit(struct libalias *); 92 93 /* Packet Handling functions. */ 94 int LibAliasIn (struct libalias *, char *_ptr, int _maxpacketsize); 95 int LibAliasOut(struct libalias *, char *_ptr, int _maxpacketsize); 96 int LibAliasOutTry(struct libalias *, char *_ptr, int _maxpacketsize, int _create); 97 int LibAliasUnaliasOut(struct libalias *, char *_ptr, int _maxpacketsize); 98 99 /* Port and address redirection functions. */ 100 101 int 102 LibAliasAddServer(struct libalias *, struct alias_link *_lnk, 103 struct in_addr _addr, unsigned short _port); 104 struct alias_link * 105 LibAliasRedirectAddr(struct libalias *, struct in_addr _src_addr, 106 struct in_addr _alias_addr); 107 int LibAliasRedirectDynamic(struct libalias *, struct alias_link *_lnk); 108 void LibAliasRedirectDelete(struct libalias *, struct alias_link *_lnk); 109 struct alias_link * 110 LibAliasRedirectPort(struct libalias *, struct in_addr _src_addr, 111 unsigned short _src_port, struct in_addr _dst_addr, 112 unsigned short _dst_port, struct in_addr _alias_addr, 113 unsigned short _alias_port, unsigned char _proto); 114 struct alias_link * 115 LibAliasRedirectProto(struct libalias *, struct in_addr _src_addr, 116 struct in_addr _dst_addr, struct in_addr _alias_addr, 117 unsigned char _proto); 118 119 /* Fragment Handling functions. */ 120 void LibAliasFragmentIn(struct libalias *, char *_ptr, char *_ptr_fragment); 121 char *LibAliasGetFragment(struct libalias *, char *_ptr); 122 int LibAliasSaveFragment(struct libalias *, char *_ptr); 123 124 /* Miscellaneous functions. */ 125 int LibAliasCheckNewLink(struct libalias *); 126 unsigned short 127 LibAliasInternetChecksum(struct libalias *, unsigned short *_ptr, int _nbytes); 128 void LibAliasSetTarget(struct libalias *, struct in_addr _target_addr); 129 130 /* Transparent proxying routines. */ 131 int LibAliasProxyRule(struct libalias *, const char *_cmd); 132 133 /* Module handling API */ 134 int LibAliasLoadModule(char *); 135 int LibAliasUnLoadAllModule(void); 136 int LibAliasRefreshModules(void); 137 138 /* Mbuf helper function. */ 139 struct mbuf *m_megapullup(struct mbuf *, int); 140 141 /* 142 * Mode flags and other constants. 143 */ 144 145 146 /* Mode flags, set using PacketAliasSetMode() */ 147 148 /* 149 * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log 150 * every time a link is created or deleted. This is useful for debugging. 151 */ 152 #define PKT_ALIAS_LOG 0x01 153 154 /* 155 * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp, 156 * telnet or web servers will be prevented by the aliasing mechanism. 157 */ 158 #define PKT_ALIAS_DENY_INCOMING 0x02 159 160 /* 161 * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the 162 * same port as they originated on. This allows e.g. rsh to work *99% of the 163 * time*, but _not_ 100% (it will be slightly flakey instead of not working 164 * at all). This mode bit is set by PacketAliasInit(), so it is a default 165 * mode of operation. 166 */ 167 #define PKT_ALIAS_SAME_PORTS 0x04 168 169 /* 170 * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g. 171 * destination port and/or address is zero), the packet aliasing engine will 172 * attempt to allocate a socket for the aliasing port it chooses. This will 173 * avoid interference with the host machine. Fully specified links do not 174 * require this. This bit is set after a call to PacketAliasInit(), so it is 175 * a default mode of operation. 176 */ 177 #ifndef NO_USE_SOCKETS 178 #define PKT_ALIAS_USE_SOCKETS 0x08 179 #endif 180 /*- 181 * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with 182 * unregistered source addresses will be aliased. Private 183 * addresses are those in the following ranges: 184 * 185 * 10.0.0.0 -> 10.255.255.255 186 * 172.16.0.0 -> 172.31.255.255 187 * 192.168.0.0 -> 192.168.255.255 188 */ 189 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10 190 191 /* 192 * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic 193 * aliasing links will be reset whenever PacketAliasSetAddress() changes the 194 * default aliasing address. If the default aliasing address is left 195 * unchanged by this function call, then the table of dynamic aliasing links 196 * will be left intact. This bit is set after a call to PacketAliasInit(). 197 */ 198 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20 199 200 /* 201 * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only 202 * transparent proxying is performed. 203 */ 204 #define PKT_ALIAS_PROXY_ONLY 0x40 205 206 /* 207 * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and 208 * PacketAliasOut() are reversed. 209 */ 210 #define PKT_ALIAS_REVERSE 0x80 211 212 #ifndef NO_FW_PUNCH 213 /* 214 * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will 215 * create a 'hole' in the firewall to allow the transfers to work. The 216 * ipfw rule number that the hole is created with is controlled by 217 * PacketAliasSetFWBase(). The hole will be attached to that 218 * particular alias_link, so when the link goes away the hole is deleted. 219 */ 220 #define PKT_ALIAS_PUNCH_FW 0x100 221 #endif 222 223 /* 224 * If PKT_ALIAS_SKIP_GLOBAL is set, nat instance is not checked for matching 225 * states in 'ipfw nat global' rule. 226 */ 227 #define PKT_ALIAS_SKIP_GLOBAL 0x200 228 229 /* Function return codes. */ 230 #define PKT_ALIAS_ERROR -1 231 #define PKT_ALIAS_OK 1 232 #define PKT_ALIAS_IGNORED 2 233 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3 234 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4 235 236 #endif /* !_ALIAS_H_ */ 237 238 /* lint -restore */ 239