alias/alias.h

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*-
  23  * Copyright (c) 2001 Charles Mott <cmott@scientech.com>
  24  * All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  *
  35  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  36  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  37  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  38  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  39  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  40  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  41  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  42  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  43  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  44  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  45  * SUCH DAMAGE.
  46  *
  47  * Based upon:
  48  * $FreeBSD: src/lib/libalias/alias.h,v 1.12.2.4 2001/08/01 09:36:40 obrien Exp $
  49  */
  50
  51 /*-
  52  * Alias.h defines the outside world interfaces for the packet aliasing
  53  * software.
  54  *
  55  * This software is placed into the public domain with no restrictions on its
  56  * distribution.
  57  */
  58
  59 #ifndef _ALIAS_H_
  60 #define _ALIAS_H_
  61
  62 /* Alias link representative (incomplete struct) */
  63 struct alias_link;
  64
  65 /* External interfaces (API) to packet aliasing engine */
  66
  67 /* Initialization and Control */
  68     extern void
  69     PacketAliasInit(void);
  70
  71     extern void
  72     PacketAliasUninit(void);
  73
  74     extern void
  75     PacketAliasSetAddress(struct in_addr);
  76
  77     extern unsigned int
  78     PacketAliasSetMode(unsigned int, unsigned int);
  79
  80 #ifndef NO_FW_PUNCH
  81     extern void
  82     PacketAliasSetFWBase(unsigned int, unsigned int);
  83 #endif
  84
  85     extern void
  86     PacketAliasClampMSS(u_short mss);
  87
  88 /* Packet Handling */
  89     extern int
  90     PacketAliasIn(char *, int maxpacketsize);
  91
  92     extern int
  93     PacketAliasOut(char *, int maxpacketsize);
  94
  95     extern int
  96     PacketUnaliasOut(char *, int maxpacketsize);
  97
  98 /* Port and Address Redirection */
  99     extern struct alias_link *
 100     PacketAliasRedirectPort(struct in_addr, u_short,
 101                             struct in_addr, u_short,
 102                             struct in_addr, u_short,
 103                             u_char);
 104
 105     extern int
 106     PacketAliasAddServer(struct alias_link *link,
 107                          struct in_addr addr,
 108                          u_short port);
 109
 110     extern struct alias_link *
 111     PacketAliasRedirectProto(struct in_addr,
 112                              struct in_addr,
 113                              struct in_addr,
 114                              u_char);
 115
 116     extern struct alias_link *
 117     PacketAliasRedirectAddr(struct in_addr,
 118                             struct in_addr);
 119
 120     extern void
 121     PacketAliasRedirectDelete(struct alias_link *);
 122
 123 /* Fragment Handling */
 124     extern int
 125     PacketAliasSaveFragment(char *);
 126
 127     extern char *
 128     PacketAliasGetFragment(char *);
 129
 130     extern void
 131     PacketAliasFragmentIn(char *, char *);
 132
 133 /* Miscellaneous Functions */
 134     extern void
 135     PacketAliasSetTarget(struct in_addr addr);
 136
 137     extern int
 138     PacketAliasCheckNewLink(void);
 139
 140     extern u_short
 141     PacketAliasInternetChecksum(u_short *, int);
 142
 143 /* Transparent Proxying */
 144     extern int
 145     PacketAliasProxyRule(const char *);
 146
 147
 148 /********************** Mode flags ********************/
 149 /* Set these flags using PacketAliasSetMode() */
 150
 151 /* If PKT_ALIAS_LOG is set, a message will be printed to
 152         /var/log/alias.log every time a link is created or deleted.  This
 153         is useful for debugging */
 154 #define PKT_ALIAS_LOG 0x01
 155
 156 /* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g.
 157         to ftp, telnet or web servers will be prevented by the aliasing
 158         mechanism.  */
 159 #define PKT_ALIAS_DENY_INCOMING 0x02
 160
 161 /* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from
 162         the same port as they originated on.  This allows e.g. rsh to work
 163         *99% of the time*, but _not_ 100%.  (It will be slightly flakey
 164         instead of not working at all.)  This mode bit is set by
 165         PacketAliasInit(), so it is a default mode of operation. */
 166 #define PKT_ALIAS_SAME_PORTS 0x04
 167
 168 /* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified
 169         links (e.g. destination port and/or address is zero), the packet
 170         aliasing engine will attempt to allocate a socket for the aliasing
 171         port it chooses.  This will avoid interference with the host
 172         machine.  Fully specified links do not require this.  This bit
 173         is set after a call to PacketAliasInit(), so it is a default
 174         mode of operation. */
 175 #define PKT_ALIAS_USE_SOCKETS 0x08
 176
 177 /* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
 178         unregistered source addresses will be aliased.  Private
 179         addresses are those in the following ranges:
 180                 10.0.0.0     ->   10.255.255.255
 181                 172.16.0.0   ->   172.31.255.255
 182                 192.168.0.0  ->   192.168.255.255  */
 183 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10
 184
 185 /* If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
 186         aliasing links will be reset whenever PacketAliasSetAddress()
 187         changes the default aliasing address.  If the default aliasing
 188         address is left unchanged by this function call, then the
 189         table of dynamic aliasing links will be left intact.  This
 190         bit is set after a call to PacketAliasInit(). */
 191 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
 192
 193 #ifndef NO_FW_PUNCH
 194 /* If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections
 195    will create a 'hole' in the firewall to allow the transfers to
 196    work.  Where (IPFW "line-numbers") the hole is created is
 197    controlled by PacketAliasSetFWBase(base, size). The hole will be
 198    attached to that particular alias_link, so when the link goes away
 199    so do the hole.  */
 200 #define PKT_ALIAS_PUNCH_FW 0x100
 201 #endif
 202
 203 /* If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
 204       transparent proxying performed */
 205 #define PKT_ALIAS_PROXY_ONLY 0x40
 206
 207 /* If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn()
 208       and PacketAliasOut() are reversed */
 209 #define PKT_ALIAS_REVERSE 0x80
 210
 211 /* Return Codes */
 212 #define PKT_ALIAS_ERROR -1
 213 #define PKT_ALIAS_OK 1
 214 #define PKT_ALIAS_IGNORED 2
 215 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
 216 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
 217
 218 #endif
 219 /* lint -restore */