alias/alias.h

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*-
  24  * Copyright (c) 2001 Charles Mott <cmott@scientech.com>
  25  * All rights reserved.
  26  *
  27  * Redistribution and use in source and binary forms, with or without
  28  * modification, are permitted provided that the following conditions
  29  * are met:
  30  * 1. Redistributions of source code must retain the above copyright
  31  *    notice, this list of conditions and the following disclaimer.
  32  * 2. Redistributions in binary form must reproduce the above copyright
  33  *    notice, this list of conditions and the following disclaimer in the
  34  *    documentation and/or other materials provided with the distribution.
  35  *
  36  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  37  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  39  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  40  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  41  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  42  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  43  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  44  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  45  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  46  * SUCH DAMAGE.
  47  *
  48  * Based upon:
  49  * $FreeBSD: src/lib/libalias/alias.h,v 1.12.2.4 2001/08/01 09:36:40 obrien Exp $
  50  */
  51
  52 /*-
  53  * Alias.h defines the outside world interfaces for the packet aliasing
  54  * software.
  55  *
  56  * This software is placed into the public domain with no restrictions on its
  57  * distribution.
  58  */
  59
  60 #ifndef _ALIAS_H_
  61 #define _ALIAS_H_
  62
  63 /* Alias link representative (incomplete struct) */
  64 struct alias_link;
  65
  66 /* External interfaces (API) to packet aliasing engine */
  67
  68 /* Initialization and Control */
  69     extern void
  70     PacketAliasInit(void);
  71
  72     extern void
  73     PacketAliasUninit(void);
  74
  75     extern void
  76     PacketAliasSetAddress(struct in_addr);
  77
  78     extern unsigned int
  79     PacketAliasSetMode(unsigned int, unsigned int);
  80
  81 #ifndef NO_FW_PUNCH
  82     extern void
  83     PacketAliasSetFWBase(unsigned int, unsigned int);
  84 #endif
  85
  86     extern void
  87     PacketAliasClampMSS(u_short mss);
  88
  89 /* Packet Handling */
  90     extern int
  91     PacketAliasIn(char *, int maxpacketsize);
  92
  93     extern int
  94     PacketAliasOut(char *, int maxpacketsize);
  95
  96     extern int
  97     PacketUnaliasOut(char *, int maxpacketsize);
  98
  99 /* Port and Address Redirection */
 100     extern struct alias_link *
 101     PacketAliasRedirectPort(struct in_addr, u_short,
 102                             struct in_addr, u_short,
 103                             struct in_addr, u_short,
 104                             u_char);
 105
 106     extern int
 107     PacketAliasAddServer(struct alias_link *link,
 108                          struct in_addr addr,
 109                          u_short port);
 110
 111     extern struct alias_link *
 112     PacketAliasRedirectProto(struct in_addr,
 113                              struct in_addr,
 114                              struct in_addr,
 115                              u_char);
 116
 117     extern struct alias_link *
 118     PacketAliasRedirectAddr(struct in_addr,
 119                             struct in_addr);
 120
 121     extern void
 122     PacketAliasRedirectDelete(struct alias_link *);
 123
 124 /* Fragment Handling */
 125     extern int
 126     PacketAliasSaveFragment(char *);
 127
 128     extern char *
 129     PacketAliasGetFragment(char *);
 130
 131     extern void
 132     PacketAliasFragmentIn(char *, char *);
 133
 134 /* Miscellaneous Functions */
 135     extern void
 136     PacketAliasSetTarget(struct in_addr addr);
 137
 138     extern int
 139     PacketAliasCheckNewLink(void);
 140
 141     extern u_short
 142     PacketAliasInternetChecksum(u_short *, int);
 143
 144 /* Transparent Proxying */
 145     extern int
 146     PacketAliasProxyRule(const char *);
 147
 148
 149 /********************** Mode flags ********************/
 150 /* Set these flags using PacketAliasSetMode() */
 151
 152 /* If PKT_ALIAS_LOG is set, a message will be printed to
 153         /var/log/alias.log every time a link is created or deleted.  This
 154         is useful for debugging */
 155 #define PKT_ALIAS_LOG 0x01
 156
 157 /* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g.
 158         to ftp, telnet or web servers will be prevented by the aliasing
 159         mechanism.  */
 160 #define PKT_ALIAS_DENY_INCOMING 0x02
 161
 162 /* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from
 163         the same port as they originated on.  This allows e.g. rsh to work
 164         *99% of the time*, but _not_ 100%.  (It will be slightly flakey
 165         instead of not working at all.)  This mode bit is set by
 166         PacketAliasInit(), so it is a default mode of operation. */
 167 #define PKT_ALIAS_SAME_PORTS 0x04
 168
 169 /* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified
 170         links (e.g. destination port and/or address is zero), the packet
 171         aliasing engine will attempt to allocate a socket for the aliasing
 172         port it chooses.  This will avoid interference with the host
 173         machine.  Fully specified links do not require this.  This bit
 174         is set after a call to PacketAliasInit(), so it is a default
 175         mode of operation. */
 176 #define PKT_ALIAS_USE_SOCKETS 0x08
 177
 178 /* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
 179         unregistered source addresses will be aliased.  Private
 180         addresses are those in the following ranges:
 181                 10.0.0.0     ->   10.255.255.255
 182                 172.16.0.0   ->   172.31.255.255
 183                 192.168.0.0  ->   192.168.255.255  */
 184 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10
 185
 186 /* If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
 187         aliasing links will be reset whenever PacketAliasSetAddress()
 188         changes the default aliasing address.  If the default aliasing
 189         address is left unchanged by this function call, then the
 190         table of dynamic aliasing links will be left intact.  This
 191         bit is set after a call to PacketAliasInit(). */
 192 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
 193
 194 #ifndef NO_FW_PUNCH
 195 /* If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections
 196    will create a 'hole' in the firewall to allow the transfers to
 197    work.  Where (IPFW "line-numbers") the hole is created is
 198    controlled by PacketAliasSetFWBase(base, size). The hole will be
 199    attached to that particular alias_link, so when the link goes away
 200    so do the hole.  */
 201 #define PKT_ALIAS_PUNCH_FW 0x100
 202 #endif
 203
 204 /* If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
 205       transparent proxying performed */
 206 #define PKT_ALIAS_PROXY_ONLY 0x40
 207
 208 /* If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn()
 209       and PacketAliasOut() are reversed */
 210 #define PKT_ALIAS_REVERSE 0x80
 211
 212 /* Return Codes */
 213 #define PKT_ALIAS_ERROR -1
 214 #define PKT_ALIAS_OK 1
 215 #define PKT_ALIAS_IGNORED 2
 216 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
 217 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
 218
 219 #endif
 220 /* lint -restore */