1 /* lint -save -library Flexelint comment for external headers */
4 * Copyright (c) 2001 Charles Mott <cm@linktel.net>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
32 * Alias.h defines the outside world interfaces for the packet aliasing
35 * This software is placed into the public domain with no restrictions on its
42 /* The external interface to libalias, the packet aliasing engine. */
44 /* Initialization and control functions. */
45 void PacketAliasInit(void);
46 void PacketAliasSetAddress(struct in_addr _addr);
47 void PacketAliasSetFWBase(unsigned int _base, unsigned int _num);
49 PacketAliasSetMode(unsigned int _flags, unsigned int _mask);
50 void PacketAliasUninit(void);
52 /* Packet Handling functions. */
53 int PacketAliasIn(char *_ptr, int _maxpacketsize);
54 int PacketAliasOut(char *_ptr, int _maxpacketsize);
55 int PacketUnaliasOut(char *_ptr, int _maxpacketsize);
57 /* Port and address redirection functions. */
60 * An anonymous structure, a pointer to which is returned from
61 * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or
62 * PacketAliasRedirectProto(), passed to PacketAliasAddServer(),
63 * and freed by PacketAliasRedirectDelete().
67 int PacketAliasAddServer(struct alias_link *_link,
68 struct in_addr _addr, unsigned short _port);
70 PacketAliasRedirectAddr(struct in_addr _src_addr,
71 struct in_addr _alias_addr);
72 void PacketAliasRedirectDelete(struct alias_link *_link);
74 PacketAliasRedirectPort(struct in_addr _src_addr,
75 unsigned short _src_port, struct in_addr _dst_addr,
76 unsigned short _dst_port, struct in_addr _alias_addr,
77 unsigned short _alias_port, unsigned char _proto);
79 PacketAliasRedirectProto(struct in_addr _src_addr,
80 struct in_addr _dst_addr, struct in_addr _alias_addr,
81 unsigned char _proto);
83 /* Fragment Handling functions. */
84 void PacketAliasFragmentIn(char *_ptr, char *_ptr_fragment);
85 char *PacketAliasGetFragment(char *_ptr);
86 int PacketAliasSaveFragment(char *_ptr);
88 /* Miscellaneous functions. */
89 int PacketAliasCheckNewLink(void);
91 PacketAliasInternetChecksum(unsigned short *_ptr, int _nbytes);
92 void PacketAliasSetTarget(struct in_addr _target_addr);
94 /* Transparent proxying routines. */
95 int PacketAliasProxyRule(const char *_cmd);
97 /* Mode flags, set using PacketAliasSetMode() */
100 * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log
101 * every time a link is created or deleted. This is useful for debugging.
103 #define PKT_ALIAS_LOG 0x01
106 * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp,
107 * telnet or web servers will be prevented by the aliasing mechanism.
109 #define PKT_ALIAS_DENY_INCOMING 0x02
112 * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the
113 * same port as they originated on. This allows e.g. rsh to work *99% of the
114 * time*, but _not_ 100% (it will be slightly flakey instead of not working
115 * at all). This mode bit is set by PacketAliasInit(), so it is a default
118 #define PKT_ALIAS_SAME_PORTS 0x04
121 * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g.
122 * destination port and/or address is zero), the packet aliasing engine will
123 * attempt to allocate a socket for the aliasing port it chooses. This will
124 * avoid interference with the host machine. Fully specified links do not
125 * require this. This bit is set after a call to PacketAliasInit(), so it is
126 * a default mode of operation.
128 #define PKT_ALIAS_USE_SOCKETS 0x08
131 * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
132 * unregistered source addresses will be aliased. Private
133 * addresses are those in the following ranges:
135 * 10.0.0.0 -> 10.255.255.255
136 * 172.16.0.0 -> 172.31.255.255
137 * 192.168.0.0 -> 192.168.255.255
139 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10
142 * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
143 * aliasing links will be reset whenever PacketAliasSetAddress() changes the
144 * default aliasing address. If the default aliasing address is left
145 * unchanged by this function call, then the table of dynamic aliasing links
146 * will be left intact. This bit is set after a call to PacketAliasInit().
148 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
152 * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will
153 * create a 'hole' in the firewall to allow the transfers to work. The
154 * ipfw rule number that the hole is created with is controlled by
155 * PacketAliasSetFWBase(). The hole will be attached to that
156 * particular alias_link, so when the link goes away the hole is deleted.
158 #define PKT_ALIAS_PUNCH_FW 0x100
162 * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
163 * transparent proxying is performed.
165 #define PKT_ALIAS_PROXY_ONLY 0x40
168 * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and
169 * PacketAliasOut() are reversed.
171 #define PKT_ALIAS_REVERSE 0x80
173 /* Function return codes. */
174 #define PKT_ALIAS_ERROR -1
175 #define PKT_ALIAS_OK 1
176 #define PKT_ALIAS_IGNORED 2
177 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
178 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
180 #endif /* !_ALIAS_H_ */