alias.h revision 74778 
1/* lint -save -library Flexelint comment for external headers */
2
3/*-
4 * Alias.h defines the outside world interfaces for the packet aliasing
5 * software.
6 *
7 * This software is placed into the public domain with no restrictions on its
8 * distribution.
9 *
10 * $FreeBSD: head/sys/netinet/libalias/alias.h 74778 2001-03-25 12:05:10Z brian $
11 */
12
13#ifndef _ALIAS_H_
14#define	_ALIAS_H_
15
16/* The external interface to libalias, the packet aliasing engine. */
17
18/* Initialization and control functions. */
19void	 PacketAliasInit(void);
20void	 PacketAliasSetAddress(struct in_addr _addr);
21void	 PacketAliasSetFWBase(unsigned int _base, unsigned int _num);
22unsigned int
23	 PacketAliasSetMode(unsigned int _flags, unsigned int _mask);
24void	 PacketAliasUninit(void);
25
26/* Packet Handling functions. */
27int	 PacketAliasIn(char *_ptr, int _maxpacketsize);
28int	 PacketAliasOut(char *_ptr, int _maxpacketsize);
29int	 PacketUnaliasOut(char *_ptr, int _maxpacketsize);
30
31/* Port and address redirection functions. */
32
33/*
34 * An anonymous structure, a pointer to which is returned from
35 * PacketAliasRedirectAddr(), PacketAliasRedirectPort() or
36 * PacketAliasRedirectProto(), passed to PacketAliasAddServer(),
37 * and freed by PacketAliasRedirectDelete().
38 */
39struct	alias_link;
40
41int	 PacketAliasAddServer(struct alias_link *_link,
42	    struct in_addr _addr, unsigned short _port);
43struct alias_link *
44	 PacketAliasRedirectAddr(struct in_addr _src_addr,
45	    struct in_addr _alias_addr);
46void	 PacketAliasRedirectDelete(struct alias_link *_link);
47struct alias_link *
48	 PacketAliasRedirectPort(struct in_addr _src_addr,
49	    unsigned short _src_port, struct in_addr _dst_addr,
50	    unsigned short _dst_port, struct in_addr _alias_addr,
51	    unsigned short _alias_port, unsigned char _proto);
52struct alias_link *
53	 PacketAliasRedirectProto(struct in_addr _src_addr,
54	    struct in_addr _dst_addr, struct in_addr _alias_addr,
55	    unsigned char _proto);
56
57/* Fragment Handling functions. */
58void	 PacketAliasFragmentIn(char *_ptr, char *_ptr_fragment);
59char	*PacketAliasGetFragment(char *_ptr);
60int	 PacketAliasSaveFragment(char *_ptr);
61
62/* Miscellaneous functions. */
63int	 PacketAliasCheckNewLink(void);
64unsigned short
65	 PacketAliasInternetChecksum(unsigned short *_ptr, int _nbytes);
66void	 PacketAliasSetTarget(struct in_addr _target_addr);
67
68/* Transparent proxying routines. */
69int	 PacketAliasProxyRule(const char *_cmd);
70
71/* Mode flags, set using PacketAliasSetMode() */
72
73/*
74 * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log
75 * every time a link is created or deleted.  This is useful for debugging.
76 */
77#define	PKT_ALIAS_LOG			0x01
78
79/*
80 * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp,
81 * telnet or web servers will be prevented by the aliasing mechanism.
82 */
83#define	PKT_ALIAS_DENY_INCOMING		0x02
84
85/*
86 * If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the
87 * same port as they originated on.  This allows e.g. rsh to work *99% of the
88 * time*, but _not_ 100% (it will be slightly flakey instead of not working
89 * at all).  This mode bit is set by PacketAliasInit(), so it is a default
90 * mode of operation.
91 */
92#define	PKT_ALIAS_SAME_PORTS		0x04
93
94/*
95 * If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g.
96 * destination port and/or address is zero), the packet aliasing engine will
97 * attempt to allocate a socket for the aliasing port it chooses.  This will
98 * avoid interference with the host machine.  Fully specified links do not
99 * require this.  This bit is set after a call to PacketAliasInit(), so it is
100 * a default mode of operation.
101 */
102#define	PKT_ALIAS_USE_SOCKETS		0x08
103
104/*-
105 * If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
106 * unregistered source addresses will be aliased.  Private
107 * addresses are those in the following ranges:
108 *
109 *		10.0.0.0     ->   10.255.255.255
110 *		172.16.0.0   ->   172.31.255.255
111 *		192.168.0.0  ->   192.168.255.255
112 */
113#define	PKT_ALIAS_UNREGISTERED_ONLY	0x10
114
115/*
116 * If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
117 * aliasing links will be reset whenever PacketAliasSetAddress() changes the
118 * default aliasing address.  If the default aliasing address is left
119 * unchanged by this function call, then the table of dynamic aliasing links
120 * will be left intact.  This bit is set after a call to PacketAliasInit().
121 */
122#define	PKT_ALIAS_RESET_ON_ADDR_CHANGE	0x20
123
124#ifndef NO_FW_PUNCH
125/*
126 * If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will
127 * create a 'hole' in the firewall to allow the transfers to work.  The
128 * ipfw rule number that the hole is created with is controlled by
129 * PacketAliasSetFWBase().  The hole will be attached to that
130 * particular alias_link, so when the link goes away the hole is deleted.
131 */
132#define	PKT_ALIAS_PUNCH_FW		0x100
133#endif
134
135/*
136 * If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
137 * transparent proxying is performed.
138 */
139#define	PKT_ALIAS_PROXY_ONLY		0x40
140
141/*
142 * If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and
143 * PacketAliasOut() are reversed.
144 */
145#define	PKT_ALIAS_REVERSE		0x80
146
147/* Function return codes. */
148#define	PKT_ALIAS_ERROR			-1
149#define	PKT_ALIAS_OK			1
150#define	PKT_ALIAS_IGNORED		2
151#define	PKT_ALIAS_UNRESOLVED_FRAGMENT	3
152#define	PKT_ALIAS_FOUND_HEADER_FRAGMENT	4
153
154#endif /* !_ALIAS_H_ */
155
156/* lint -restore */
157