1 /* lint -save -library Flexelint comment for external headers */
4 * SPDX-License-Identifier: BSD-2-Clause
6 * Copyright (c) 2001 Charles Mott <cm@linktel.net>
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * Alias.h defines the outside world interfaces for the packet aliasing
37 * This software is placed into the public domain with no restrictions on its
44 #include <netinet/in_systm.h>
45 #include <netinet/in.h>
46 #include <netinet/ip.h>
48 #define LIBALIAS_BUF_SIZE 128
51 * The kernel version of libalias does not support these features.
54 #define NO_USE_SOCKETS
58 * The external interface to libalias, the packet aliasing engine.
60 * There are two sets of functions:
62 * PacketAlias*() the old API which doesn't take an instance pointer
63 * and therefore can only have one packet engine at a time.
65 * LibAlias*() the new API which takes as first argument a pointer to
66 * the instance of the packet aliasing engine.
68 * The functions otherwise correspond to each other one for one, except
69 * for the LibAliasUnaliasOut()/PacketUnaliasOut() function which were
70 * were misnamed in the old API.
74 * The instance structure
79 * An anonymous structure, a pointer to which is returned from
80 * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or
81 * PacketAliasRedirectProto(), passed to PacketAliasAddServer(),
82 * and freed by PacketAliasRedirectDelete().
86 /* Initialization and control functions. */
87 struct libalias *LibAliasInit(struct libalias *);
88 void LibAliasSetAddress(struct libalias *, struct in_addr _addr);
89 void LibAliasSetAliasPortRange(struct libalias *la, u_short port_low, u_short port_hi);
90 void LibAliasSetFWBase(struct libalias *, unsigned int _base, unsigned int _num);
91 void LibAliasSetSkinnyPort(struct libalias *, unsigned int _port);
92 unsigned int LibAliasSetMode(struct libalias *, unsigned int _flags, unsigned int _mask);
93 void LibAliasUninit(struct libalias *);
95 /* Packet Handling functions. */
96 int LibAliasIn (struct libalias *, void *_ptr, int _maxpacketsize);
97 int LibAliasOut(struct libalias *, void *_ptr, int _maxpacketsize);
98 int LibAliasOutTry(struct libalias *, void *_ptr, int _maxpacketsize, int _create);
99 int LibAliasUnaliasOut(struct libalias *, void *_ptr, int _maxpacketsize);
101 /* Port and address redirection functions. */
103 int LibAliasAddServer(struct libalias *, struct alias_link *_lnk,
104 struct in_addr _addr, unsigned short _port);
105 struct alias_link * LibAliasRedirectAddr(struct libalias *, struct in_addr _src_addr,
106 struct in_addr _alias_addr);
107 int LibAliasRedirectDynamic(struct libalias *, struct alias_link *_lnk);
108 void LibAliasRedirectDelete(struct libalias *, struct alias_link *_lnk);
109 struct alias_link * LibAliasRedirectPort(struct libalias *, struct in_addr _src_addr,
110 unsigned short _src_port, struct in_addr _dst_addr,
111 unsigned short _dst_port, struct in_addr _alias_addr,
112 unsigned short _alias_port, unsigned char _proto);
113 struct alias_link * LibAliasRedirectProto(struct libalias *, struct in_addr _src_addr,
114 struct in_addr _dst_addr, struct in_addr _alias_addr,
115 unsigned char _proto);
117 /* Fragment Handling functions. */
118 void LibAliasFragmentIn(struct libalias *, void *_ptr, void *_ptr_fragment);
119 void *LibAliasGetFragment(struct libalias *, void *_ptr);
120 int LibAliasSaveFragment(struct libalias *, void *_ptr);
122 /* Miscellaneous functions. */
123 unsigned short LibAliasInternetChecksum(struct libalias *, unsigned short *_ptr, int _nbytes);
124 void LibAliasSetTarget(struct libalias *, struct in_addr _target_addr);
126 /* Transparent proxying routines. */
127 int LibAliasProxyRule(struct libalias *, const char *_cmd);
129 /* Module handling API */
130 int LibAliasLoadModule(char *);
131 int LibAliasUnLoadAllModule(void);
132 int LibAliasRefreshModules(void);
134 /* Mbuf helper function. */
135 struct mbuf *m_megapullup(struct mbuf *, int);
138 * Mode flags and other constants.
141 /* Mode flags, set using PacketAliasSetMode() */
144 * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log
145 * every time a link is created or deleted. This is useful for debugging.
147 #define PKT_ALIAS_LOG 0x01
150 * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp,
151 * telnet or web servers will be prevented by the aliasing mechanism.
153 #define PKT_ALIAS_DENY_INCOMING 0x02
156 * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the
157 * same port as they originated on. This allows e.g. rsh to work *99% of the
158 * time*, but _not_ 100% (it will be slightly flakey instead of not working
159 * at all). This mode bit is set by PacketAliasInit(), so it is a default
162 #define PKT_ALIAS_SAME_PORTS 0x04
165 * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g.
166 * destination port and/or address is zero), the packet aliasing engine will
167 * attempt to allocate a socket for the aliasing port it chooses. This will
168 * avoid interference with the host machine. Fully specified links do not
169 * require this. This bit is set after a call to PacketAliasInit(), so it is
170 * a default mode of operation.
172 #ifndef NO_USE_SOCKETS
173 #define PKT_ALIAS_USE_SOCKETS 0x08
176 * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
177 * unregistered source addresses will be aliased. Private
178 * 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
184 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10
187 * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
188 * aliasing links will be reset whenever PacketAliasSetAddress() changes the
189 * default aliasing address. If the default aliasing address is left
190 * unchanged by this function call, then the table of dynamic aliasing links
191 * will be left intact. This bit is set after a call to PacketAliasInit().
193 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
196 * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
197 * transparent proxying is performed.
199 #define PKT_ALIAS_PROXY_ONLY 0x40
202 * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and
203 * PacketAliasOut() are reversed.
205 #define PKT_ALIAS_REVERSE 0x80
209 * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will
210 * create a 'hole' in the firewall to allow the transfers to work. The
211 * ipfw rule number that the hole is created with is controlled by
212 * PacketAliasSetFWBase(). The hole will be attached to that
213 * particular alias_link, so when the link goes away the hole is deleted.
215 #define PKT_ALIAS_PUNCH_FW 0x100
219 * If PKT_ALIAS_SKIP_GLOBAL is set, nat instance is not checked for matching
220 * states in 'ipfw nat global' rule.
222 #define PKT_ALIAS_SKIP_GLOBAL 0x200
225 * Like PKT_ALIAS_UNREGISTERED_ONLY, but includes the RFC 6598
226 * (Carrier Grade NAT) address range as follows:
228 * 100.64.0.0 -> 100.127.255.255
230 #define PKT_ALIAS_UNREGISTERED_CGN 0x400
232 /* Function return codes. */
233 #define PKT_ALIAS_ERROR -1
234 #define PKT_ALIAS_OK 1
235 #define PKT_ALIAS_IGNORED 2
236 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
237 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
239 #endif /* !_ALIAS_H_ */