lib/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/lib/libalias/alias.h,v 1.12.2.6 2001/11/23 13:10:15 brian Exp $
  29  * $DragonFly: src/lib/libalias/alias.h,v 1.2 2003/06/17 06:26:41 dillon Exp $
  30  */
  31
  32 /*-
  33  * Alias.h defines the outside world interfaces for the packet aliasing
  34  * software.
  35  *
  36  * This software is placed into the public domain with no restrictions on its
  37  * distribution.
  38  */
  39
  40 #ifndef _ALIAS_H_
  41 #define _ALIAS_H_
  42
  43 /* The external interface to libalias, the packet aliasing engine. */
  44
  45 /* Initialization and control functions. */
  46 void     PacketAliasInit(void);
  47 void     PacketAliasSetAddress(struct in_addr _addr);
  48 void     PacketAliasSetFWBase(unsigned int _base, unsigned int _num);
  49 unsigned int
  50          PacketAliasSetMode(unsigned int _flags, unsigned int _mask);
  51 void     PacketAliasUninit(void);
  52
  53 /* Packet Handling functions. */
  54 int      PacketAliasIn(char *_ptr, int _maxpacketsize);
  55 int      PacketAliasOut(char *_ptr, int _maxpacketsize);
  56 int      PacketUnaliasOut(char *_ptr, int _maxpacketsize);
  57
  58 /* Port and address redirection functions. */
  59
  60 /*
  61  * An anonymous structure, a pointer to which is returned from
  62  * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or
  63  * PacketAliasRedirectProto(), passed to PacketAliasAddServer(),
  64  * and freed by PacketAliasRedirectDelete().
  65  */
  66 struct  alias_link;
  67
  68 int      PacketAliasAddServer(struct alias_link *_link,
  69             struct in_addr _addr, unsigned short _port);
  70 struct alias_link *
  71          PacketAliasRedirectAddr(struct in_addr _src_addr,
  72             struct in_addr _alias_addr);
  73 void     PacketAliasRedirectDelete(struct alias_link *_link);
  74 struct alias_link *
  75          PacketAliasRedirectPort(struct in_addr _src_addr,
  76             unsigned short _src_port, struct in_addr _dst_addr,
  77             unsigned short _dst_port, struct in_addr _alias_addr,
  78             unsigned short _alias_port, unsigned char _proto);
  79 struct alias_link *
  80          PacketAliasRedirectProto(struct in_addr _src_addr,
  81             struct in_addr _dst_addr, struct in_addr _alias_addr,
  82             unsigned char _proto);
  83
  84 /* Fragment Handling functions. */
  85 void     PacketAliasFragmentIn(char *_ptr, char *_ptr_fragment);
  86 char    *PacketAliasGetFragment(char *_ptr);
  87 int      PacketAliasSaveFragment(char *_ptr);
  88
  89 /* Miscellaneous functions. */
  90 int      PacketAliasCheckNewLink(void);
  91 unsigned short
  92          PacketAliasInternetChecksum(unsigned short *_ptr, int _nbytes);
  93 void     PacketAliasSetTarget(struct in_addr _target_addr);
  94
  95 /* Transparent proxying routines. */
  96 int      PacketAliasProxyRule(const char *_cmd);
  97
  98 /* Mode flags, set using PacketAliasSetMode() */
  99
 100 /*
 101  * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log
 102  * every time a link is created or deleted.  This is useful for debugging.
 103  */
 104 #define PKT_ALIAS_LOG                   0x01
 105
 106 /*
 107  * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp,
 108  * telnet or web servers will be prevented by the aliasing mechanism.
 109  */
 110 #define PKT_ALIAS_DENY_INCOMING         0x02
 111
 112 /*
 113  * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the
 114  * same port as they originated on.  This allows e.g. rsh to work *99% of the
 115  * time*, but _not_ 100% (it will be slightly flakey instead of not working
 116  * at all).  This mode bit is set by PacketAliasInit(), so it is a default
 117  * mode of operation.
 118  */
 119 #define PKT_ALIAS_SAME_PORTS            0x04
 120
 121 /*
 122  * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g.
 123  * destination port and/or address is zero), the packet aliasing engine will
 124  * attempt to allocate a socket for the aliasing port it chooses.  This will
 125  * avoid interference with the host machine.  Fully specified links do not
 126  * require this.  This bit is set after a call to PacketAliasInit(), so it is
 127  * a default mode of operation.
 128  */
 129 #define PKT_ALIAS_USE_SOCKETS           0x08
 130
 131 /*-
 132  * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
 133  * unregistered source addresses will be aliased.  Private
 134  * addresses are those in the following ranges:
 135  *
 136  *              10.0.0.0     ->   10.255.255.255
 137  *              172.16.0.0   ->   172.31.255.255
 138  *              192.168.0.0  ->   192.168.255.255
 139  */
 140 #define PKT_ALIAS_UNREGISTERED_ONLY     0x10
 141
 142 /*
 143  * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
 144  * aliasing links will be reset whenever PacketAliasSetAddress() changes the
 145  * default aliasing address.  If the default aliasing address is left
 146  * unchanged by this function call, then the table of dynamic aliasing links
 147  * will be left intact.  This bit is set after a call to PacketAliasInit().
 148  */
 149 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE  0x20
 150
 151 #ifndef NO_FW_PUNCH
 152 /*
 153  * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will
 154  * create a 'hole' in the firewall to allow the transfers to work.  The
 155  * ipfw rule number that the hole is created with is controlled by
 156  * PacketAliasSetFWBase().  The hole will be attached to that
 157  * particular alias_link, so when the link goes away the hole is deleted.
 158  */
 159 #define PKT_ALIAS_PUNCH_FW              0x100
 160 #endif
 161
 162 /*
 163  * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
 164  * transparent proxying is performed.
 165  */
 166 #define PKT_ALIAS_PROXY_ONLY            0x40
 167
 168 /*
 169  * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and
 170  * PacketAliasOut() are reversed.
 171  */
 172 #define PKT_ALIAS_REVERSE               0x80
 173
 174 /* Function return codes. */
 175 #define PKT_ALIAS_ERROR                 -1
 176 #define PKT_ALIAS_OK                    1
 177 #define PKT_ALIAS_IGNORED               2
 178 #define PKT_ALIAS_UNRESOLVED_FRAGMENT   3
 179 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
 180
 181 #endif /* !_ALIAS_H_ */
 182
 183 /* lint -restore */