sys/net/libalias/alias.h

   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: src/sys/netinet/libalias/alias.h,v 1.34.6.1 2008/11/25 02:59:29 kensmith Exp $
  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
  54 MALLOC_DECLARE(M_ALIAS);
  55
  56 #endif
  57
  58 /*
  59  * The external interface to libalias, the packet aliasing engine.
  60  *
  61  * There are two sets of functions:
  62  *
  63  * PacketAlias*() the old API which doesn't take an instance pointer
  64  * and therefore can only have one packet engine at a time.
  65  *
  66  * LibAlias*() the new API which takes as first argument a pointer to
  67  * the instance of the packet aliasing engine.
  68  *
  69  * The functions otherwise correspond to each other one for one, except
  70  * for the LibAliasUnaliasOut()/PacketUnaliasOut() function which were
  71  * were misnamed in the old API.
  72  */
  73
  74 /*
  75  * The instance structure
  76  */
  77 struct libalias;
  78
  79 /*
  80  * An anonymous structure, a pointer to which is returned from
  81  * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or
  82  * PacketAliasRedirectProto(), passed to PacketAliasAddServer(),
  83  * and freed by PacketAliasRedirectDelete().
  84  */
  85 struct alias_link;
  86
  87
  88 /* OLD API */
  89
  90 /* Initialization and control functions. */
  91 void            PacketAliasInit(void);
  92 void            PacketAliasSetAddress(struct in_addr _addr);
  93 void            PacketAliasSetFWBase(unsigned int _base, unsigned int _num);
  94 void            PacketAliasSetSkinnyPort(unsigned int _port);
  95 unsigned int
  96                 PacketAliasSetMode(unsigned int _flags, unsigned int _mask);
  97 void            PacketAliasUninit(void);
  98
  99 /* Packet Handling functions. */
 100 int             PacketAliasIn(char *_ptr, int _maxpacketsize);
 101 int             PacketAliasOut(char *_ptr, int _maxpacketsize);
 102 int             PacketUnaliasOut(char *_ptr, int _maxpacketsize);
 103
 104 /* Port and address redirection functions. */
 105
 106
 107 int
 108 PacketAliasAddServer(struct alias_link *_lnk,
 109         struct in_addr _addr, unsigned short _port);
 110 struct alias_link *
 111 PacketAliasRedirectAddr(struct in_addr _src_addr,
 112         struct in_addr _alias_addr);
 113 int             PacketAliasRedirectDynamic(struct alias_link *_lnk);
 114 void            PacketAliasRedirectDelete(struct alias_link *_lnk);
 115 struct alias_link *
 116 PacketAliasRedirectPort(struct in_addr _src_addr,
 117         unsigned short _src_port, struct in_addr _dst_addr,
 118         unsigned short _dst_port, struct in_addr _alias_addr,
 119         unsigned short _alias_port, unsigned char _proto);
 120 struct alias_link *
 121 PacketAliasRedirectProto(struct in_addr _src_addr,
 122         struct in_addr _dst_addr, struct in_addr _alias_addr,
 123         unsigned char _proto);
 124
 125 /* Fragment Handling functions. */
 126 void            PacketAliasFragmentIn(char *_ptr, char *_ptr_fragment);
 127 char               *PacketAliasGetFragment(char *_ptr);
 128 int             PacketAliasSaveFragment(char *_ptr);
 129
 130 /* Miscellaneous functions. */
 131 int             PacketAliasCheckNewLink(void);
 132 unsigned short
 133                 PacketAliasInternetChecksum(unsigned short *_ptr, int _nbytes);
 134 void            PacketAliasSetTarget(struct in_addr _target_addr);
 135
 136 /* Transparent proxying routines. */
 137 int             PacketAliasProxyRule(const char *_cmd);
 138
 139 /* NEW API */
 140
 141 /* Initialization and control functions. */
 142 struct libalias *LibAliasInit(struct libalias *);
 143 void            LibAliasSetAddress(struct libalias *, struct in_addr _addr);
 144 void            LibAliasSetFWBase(struct libalias *, unsigned int _base, unsigned int _num);
 145 void            LibAliasSetSkinnyPort(struct libalias *, unsigned int _port);
 146 unsigned int
 147                 LibAliasSetMode(struct libalias *, unsigned int _flags, unsigned int _mask);
 148 void            LibAliasUninit(struct libalias *);
 149
 150 /* Packet Handling functions. */
 151 int             LibAliasIn (struct libalias *, char *_ptr, int _maxpacketsize);
 152 int             LibAliasOut(struct libalias *, char *_ptr, int _maxpacketsize);
 153 int             LibAliasOutTry(struct libalias *, char *_ptr, int _maxpacketsize, int _create);
 154 int             LibAliasUnaliasOut(struct libalias *, char *_ptr, int _maxpacketsize);
 155
 156 /* Port and address redirection functions. */
 157
 158 int
 159 LibAliasAddServer(struct libalias *, struct alias_link *_lnk,
 160         struct in_addr _addr, unsigned short _port);
 161 struct alias_link *
 162 LibAliasRedirectAddr(struct libalias *, struct in_addr _src_addr,
 163         struct in_addr _alias_addr);
 164 int             LibAliasRedirectDynamic(struct libalias *, struct alias_link *_lnk);
 165 void            LibAliasRedirectDelete(struct libalias *, struct alias_link *_lnk);
 166 struct alias_link *
 167 LibAliasRedirectPort(struct libalias *, struct in_addr _src_addr,
 168         unsigned short _src_port, struct in_addr _dst_addr,
 169         unsigned short _dst_port, struct in_addr _alias_addr,
 170         unsigned short _alias_port, unsigned char _proto);
 171 struct alias_link *
 172 LibAliasRedirectProto(struct libalias *, struct in_addr _src_addr,
 173         struct in_addr _dst_addr, struct in_addr _alias_addr,
 174         unsigned char _proto);
 175
 176 /* Fragment Handling functions. */
 177 void            LibAliasFragmentIn(struct libalias *, char *_ptr, char *_ptr_fragment);
 178 char               *LibAliasGetFragment(struct libalias *, char *_ptr);
 179 int             LibAliasSaveFragment(struct libalias *, char *_ptr);
 180
 181 /* Miscellaneous functions. */
 182 int             LibAliasCheckNewLink(struct libalias *);
 183 unsigned short
 184                 LibAliasInternetChecksum(struct libalias *, unsigned short *_ptr, int _nbytes);
 185 void            LibAliasSetTarget(struct libalias *, struct in_addr _target_addr);
 186
 187 /* Transparent proxying routines. */
 188 int             LibAliasProxyRule(struct libalias *, const char *_cmd);
 189
 190 /* Module handling API */
 191 int                      LibAliasLoadModule(char *);
 192 int                      LibAliasUnLoadAllModule(void);
 193 int                      LibAliasRefreshModules(void);
 194
 195 /* Mbuf helper function. */
 196 struct mbuf     *m_megapullup(struct mbuf *, int);
 197
 198 /*
 199  * Mode flags and other constants.
 200  */
 201
 202
 203 /* Mode flags, set using PacketAliasSetMode() */
 204
 205 /*
 206  * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log
 207  * every time a link is created or deleted.  This is useful for debugging.
 208  */
 209 #define PKT_ALIAS_LOG                   0x01
 210
 211 /*
 212  * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp,
 213  * telnet or web servers will be prevented by the aliasing mechanism.
 214  */
 215 #define PKT_ALIAS_DENY_INCOMING         0x02
 216
 217 /*
 218  * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the
 219  * same port as they originated on.  This allows e.g. rsh to work *99% of the
 220  * time*, but _not_ 100% (it will be slightly flakey instead of not working
 221  * at all).  This mode bit is set by PacketAliasInit(), so it is a default
 222  * mode of operation.
 223  */
 224 #define PKT_ALIAS_SAME_PORTS            0x04
 225
 226 /*
 227  * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g.
 228  * destination port and/or address is zero), the packet aliasing engine will
 229  * attempt to allocate a socket for the aliasing port it chooses.  This will
 230  * avoid interference with the host machine.  Fully specified links do not
 231  * require this.  This bit is set after a call to PacketAliasInit(), so it is
 232  * a default mode of operation.
 233  */
 234 #ifndef NO_USE_SOCKETS
 235 #define PKT_ALIAS_USE_SOCKETS           0x08
 236 #endif
 237 /*-
 238  * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
 239  * unregistered source addresses will be aliased.  Private
 240  * addresses are those in the following ranges:
 241  *
 242  *              10.0.0.0         ->   10.255.255.255
 243  *              172.16.0.0   ->   172.31.255.255
 244  *              192.168.0.0  ->   192.168.255.255
 245  */
 246 #define PKT_ALIAS_UNREGISTERED_ONLY     0x10
 247
 248 /*
 249  * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
 250  * aliasing links will be reset whenever PacketAliasSetAddress() changes the
 251  * default aliasing address.  If the default aliasing address is left
 252  * unchanged by this function call, then the table of dynamic aliasing links
 253  * will be left intact.  This bit is set after a call to PacketAliasInit().
 254  */
 255 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE  0x20
 256
 257 #ifndef NO_FW_PUNCH
 258 /*
 259  * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will
 260  * create a 'hole' in the firewall to allow the transfers to work.  The
 261  * ipfw rule number that the hole is created with is controlled by
 262  * PacketAliasSetFWBase().  The hole will be attached to that
 263  * particular alias_link, so when the link goes away the hole is deleted.
 264  */
 265 #define PKT_ALIAS_PUNCH_FW              0x100
 266 #endif
 267
 268 /*
 269  * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
 270  * transparent proxying is performed.
 271  */
 272 #define PKT_ALIAS_PROXY_ONLY            0x40
 273
 274 /*
 275  * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and
 276  * PacketAliasOut() are reversed.
 277  */
 278 #define PKT_ALIAS_REVERSE               0x80
 279
 280 /* Function return codes. */
 281 #define PKT_ALIAS_ERROR                 -1
 282 #define PKT_ALIAS_OK                    1
 283 #define PKT_ALIAS_IGNORED               2
 284 #define PKT_ALIAS_UNRESOLVED_FRAGMENT   3
 285 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
 286
 287
 288
 289 #endif                          /* !_ALIAS_H_ */
 290
 291 /* lint -restore */