alias.h revision 59046 
1/*lint -save -library Flexelint comment for external headers */
2
3/*
4    Alias.h defines the outside world interfaces for the packet
5    aliasing software.
6
7    This software is placed into the public domain with no restrictions
8    on its distribution.
9
10 $FreeBSD: head/sys/netinet/libalias/alias.h 59046 2000-04-05 14:23:42Z ru $
11*/
12
13
14#ifndef _ALIAS_H_
15#define _ALIAS_H_
16
17/* Alias link representative (incomplete struct) */
18struct alias_link;
19
20/* External interfaces (API) to packet aliasing engine */
21
22/* Initialization and Control */
23    extern void
24    PacketAliasInit(void);
25
26    extern void
27    PacketAliasUninit(void);
28
29    extern void
30    PacketAliasSetAddress(struct in_addr);
31
32    extern unsigned int
33    PacketAliasSetMode(unsigned int, unsigned int);
34
35#ifndef NO_FW_PUNCH
36    extern void
37    PacketAliasSetFWBase(unsigned int, unsigned int);
38#endif
39
40/* Packet Handling */
41    extern int
42    PacketAliasIn(char *, int maxpacketsize);
43
44    extern int
45    PacketAliasOut(char *, int maxpacketsize);
46
47/* Port and Address Redirection */
48    extern struct alias_link *
49    PacketAliasRedirectPort(struct in_addr, u_short,
50                            struct in_addr, u_short,
51                            struct in_addr, u_short,
52                            u_char);
53
54    extern int
55    PacketAliasPptp(struct in_addr);
56
57
58    extern struct alias_link *
59    PacketAliasRedirectAddr(struct in_addr,
60                            struct in_addr);
61
62    extern void
63    PacketAliasRedirectDelete(struct alias_link *);
64
65/* Fragment Handling */
66    extern int
67    PacketAliasSaveFragment(char *);
68
69    extern char *
70    PacketAliasGetFragment(char *);
71
72    extern void
73    PacketAliasFragmentIn(char *, char *);
74
75/* Miscellaneous Functions */
76    extern void
77    PacketAliasSetTarget(struct in_addr addr);
78
79    extern int
80    PacketAliasCheckNewLink(void);
81
82    extern u_short
83    PacketAliasInternetChecksum(u_short *, int);
84
85/* Transparent Proxying */
86    extern int
87    PacketAliasProxyRule(const char *);
88
89
90/********************** Mode flags ********************/
91/* Set these flags using PacketAliasSetMode() */
92
93/* If PKT_ALIAS_LOG is set, a message will be printed to
94	/var/log/alias.log every time a link is created or deleted.  This
95	is useful for debugging */
96#define PKT_ALIAS_LOG 0x01
97
98/* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g.
99	to ftp, telnet or web servers will be prevented by the aliasing
100	mechanism.  */
101#define PKT_ALIAS_DENY_INCOMING 0x02
102
103/* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from
104	the same port as they originated on.  This allows e.g. rsh to work
105	*99% of the time*, but _not_ 100%.  (It will be slightly flakey
106	instead of not working at all.)  This mode bit is set by
107        PacketAliasInit(), so it is a default mode of operation. */
108#define PKT_ALIAS_SAME_PORTS 0x04
109
110/* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified
111	links (e.g. destination port and/or address is zero), the packet
112	aliasing engine will attempt to allocate a socket for the aliasing
113	port it chooses.  This will avoid interference with the host
114	machine.  Fully specified links do not require this.  This bit
115        is set after a call to PacketAliasInit(), so it is a default
116        mode of operation.*/
117#define PKT_ALIAS_USE_SOCKETS 0x08
118
119/* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
120	unregistered source addresses will be aliased (along with those
121	of the ppp host maching itself.  Private addresses are those
122        in the following ranges:
123		10.0.0.0     ->   10.255.255.255
124		172.16.0.0   ->   172.31.255.255
125		192.168.0.0  ->   192.168.255.255  */
126#define PKT_ALIAS_UNREGISTERED_ONLY 0x10
127
128/* If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
129	aliasing links will be reset whenever PacketAliasSetAddress()
130        changes the default aliasing address.  If the default aliasing
131        address is left unchanged by this functions call, then the
132        table of dynamic aliasing links will be left intact.  This
133        bit is set after a call to PacketAliasInit(). */
134#define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
135
136#ifndef NO_FW_PUNCH
137/* If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections
138   will create a 'hole' in the firewall to allow the transfers to
139   work.  Where (IPFW "line-numbers") the hole is created is
140   controlled by PacketAliasSetFWBase(base, size). The hole will be
141   attached to that particular alias_link, so when the link goes away
142   so do the hole.  */
143#define PKT_ALIAS_PUNCH_FW 0x100
144#endif
145
146/* If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
147      transparent proxying performed */
148#define PKT_ALIAS_PROXY_ONLY 0x40
149
150/* If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn()
151      and PacketAliasOut() are reversed */
152#define PKT_ALIAS_REVERSE 0x80
153
154/* Return Codes */
155#define PKT_ALIAS_ERROR -1
156#define PKT_ALIAS_OK 1
157#define PKT_ALIAS_IGNORED 2
158#define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
159#define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
160
161#endif
162/*lint -restore */
163