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 * $FreeBSD$
29 */
30
31/*
32 * Alias.h defines the outside world interfaces for the packet aliasing
33 * software.
34 *
35 * This software is placed into the public domain with no restrictions on its
36 * distribution.
37 */
38
39#ifndef _ALIAS_H_
40#define	_ALIAS_H_
41
42#include <netinet/in_systm.h>
43#include <netinet/in.h>
44#include <netinet/ip.h>
45
46#define LIBALIAS_BUF_SIZE 128
47#ifdef	_KERNEL
48/*
49 * The kernel version of libalias does not support these features.
50 */
51#define	NO_FW_PUNCH
52#define	NO_USE_SOCKETS
53#endif
54
55/*
56 * The external interface to libalias, the packet aliasing engine.
57 *
58 * There are two sets of functions:
59 *
60 * PacketAlias*() the old API which doesn't take an instance pointer
61 * and therefore can only have one packet engine at a time.
62 *
63 * LibAlias*() the new API which takes as first argument a pointer to
64 * the instance of the packet aliasing engine.
65 *
66 * The functions otherwise correspond to each other one for one, except
67 * for the LibAliasUnaliasOut()/PacketUnaliasOut() function which were
68 * were misnamed in the old API.
69 */
70
71/*
72 * The instance structure
73 */
74struct libalias;
75
76/*
77 * An anonymous structure, a pointer to which is returned from
78 * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or
79 * PacketAliasRedirectProto(), passed to PacketAliasAddServer(),
80 * and freed by PacketAliasRedirectDelete().
81 */
82struct alias_link;
83
84/* Initialization and control functions. */
85struct libalias *LibAliasInit(struct libalias *);
86void		LibAliasSetAddress(struct libalias *, struct in_addr _addr);
87void		LibAliasSetFWBase(struct libalias *, unsigned int _base, unsigned int _num);
88void		LibAliasSetSkinnyPort(struct libalias *, unsigned int _port);
89unsigned int
90		LibAliasSetMode(struct libalias *, unsigned int _flags, unsigned int _mask);
91void		LibAliasUninit(struct libalias *);
92
93/* Packet Handling functions. */
94int		LibAliasIn (struct libalias *, char *_ptr, int _maxpacketsize);
95int		LibAliasOut(struct libalias *, char *_ptr, int _maxpacketsize);
96int		LibAliasOutTry(struct libalias *, char *_ptr, int _maxpacketsize, int _create);
97int		LibAliasUnaliasOut(struct libalias *, char *_ptr, int _maxpacketsize);
98
99/* Port and address redirection functions. */
100
101int
102LibAliasAddServer(struct libalias *, struct alias_link *_lnk,
103    struct in_addr _addr, unsigned short _port);
104struct alias_link *
105LibAliasRedirectAddr(struct libalias *, struct in_addr _src_addr,
106    struct in_addr _alias_addr);
107int		LibAliasRedirectDynamic(struct libalias *, struct alias_link *_lnk);
108void		LibAliasRedirectDelete(struct libalias *, struct alias_link *_lnk);
109struct alias_link *
110LibAliasRedirectPort(struct libalias *, struct in_addr _src_addr,
111    unsigned short _src_port, struct in_addr _dst_addr,
112    unsigned short _dst_port, struct in_addr _alias_addr,
113    unsigned short _alias_port, unsigned char _proto);
114struct alias_link *
115LibAliasRedirectProto(struct libalias *, struct in_addr _src_addr,
116    struct in_addr _dst_addr, struct in_addr _alias_addr,
117    unsigned char _proto);
118
119/* Fragment Handling functions. */
120void		LibAliasFragmentIn(struct libalias *, char *_ptr, char *_ptr_fragment);
121char           *LibAliasGetFragment(struct libalias *, char *_ptr);
122int		LibAliasSaveFragment(struct libalias *, char *_ptr);
123
124/* Miscellaneous functions. */
125int		LibAliasCheckNewLink(struct libalias *);
126unsigned short
127		LibAliasInternetChecksum(struct libalias *, unsigned short *_ptr, int _nbytes);
128void		LibAliasSetTarget(struct libalias *, struct in_addr _target_addr);
129
130/* Transparent proxying routines. */
131int		LibAliasProxyRule(struct libalias *, const char *_cmd);
132
133/* Module handling API */
134int             LibAliasLoadModule(char *);
135int             LibAliasUnLoadAllModule(void);
136int             LibAliasRefreshModules(void);
137
138/* Mbuf helper function. */
139struct mbuf    *m_megapullup(struct mbuf *, int);
140
141/*
142 * Mode flags and other constants.
143 */
144
145
146/* Mode flags, set using PacketAliasSetMode() */
147
148/*
149 * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log
150 * every time a link is created or deleted.  This is useful for debugging.
151 */
152#define	PKT_ALIAS_LOG			0x01
153
154/*
155 * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp,
156 * telnet or web servers will be prevented by the aliasing mechanism.
157 */
158#define	PKT_ALIAS_DENY_INCOMING		0x02
159
160/*
161 * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the
162 * same port as they originated on.  This allows e.g. rsh to work *99% of the
163 * time*, but _not_ 100% (it will be slightly flakey instead of not working
164 * at all).  This mode bit is set by PacketAliasInit(), so it is a default
165 * mode of operation.
166 */
167#define	PKT_ALIAS_SAME_PORTS		0x04
168
169/*
170 * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g.
171 * destination port and/or address is zero), the packet aliasing engine will
172 * attempt to allocate a socket for the aliasing port it chooses.  This will
173 * avoid interference with the host machine.  Fully specified links do not
174 * require this.  This bit is set after a call to PacketAliasInit(), so it is
175 * a default mode of operation.
176 */
177#ifndef	NO_USE_SOCKETS
178#define	PKT_ALIAS_USE_SOCKETS		0x08
179#endif
180/*-
181 * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
182 * unregistered source addresses will be aliased.  Private
183 * addresses are those in the following ranges:
184 *
185 *		10.0.0.0     ->   10.255.255.255
186 *		172.16.0.0   ->   172.31.255.255
187 *		192.168.0.0  ->   192.168.255.255
188 */
189#define	PKT_ALIAS_UNREGISTERED_ONLY	0x10
190
191/*
192 * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
193 * aliasing links will be reset whenever PacketAliasSetAddress() changes the
194 * default aliasing address.  If the default aliasing address is left
195 * unchanged by this function call, then the table of dynamic aliasing links
196 * will be left intact.  This bit is set after a call to PacketAliasInit().
197 */
198#define	PKT_ALIAS_RESET_ON_ADDR_CHANGE	0x20
199
200/*
201 * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
202 * transparent proxying is performed.
203 */
204#define	PKT_ALIAS_PROXY_ONLY		0x40
205
206/*
207 * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and
208 * PacketAliasOut() are reversed.
209 */
210#define	PKT_ALIAS_REVERSE		0x80
211
212#ifndef NO_FW_PUNCH
213/*
214 * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will
215 * create a 'hole' in the firewall to allow the transfers to work.  The
216 * ipfw rule number that the hole is created with is controlled by
217 * PacketAliasSetFWBase().  The hole will be attached to that
218 * particular alias_link, so when the link goes away the hole is deleted.
219 */
220#define	PKT_ALIAS_PUNCH_FW		0x100
221#endif
222
223/*
224 * If PKT_ALIAS_SKIP_GLOBAL is set, nat instance is not checked for matching
225 * states in 'ipfw nat global' rule.
226 */
227#define	PKT_ALIAS_SKIP_GLOBAL		0x200
228
229/* Function return codes. */
230#define	PKT_ALIAS_ERROR			-1
231#define	PKT_ALIAS_OK			1
232#define	PKT_ALIAS_IGNORED		2
233#define	PKT_ALIAS_UNRESOLVED_FRAGMENT	3
234#define	PKT_ALIAS_FOUND_HEADER_FRAGMENT	4
235
236#endif				/* !_ALIAS_H_ */
237
238/* lint -restore */
239