alias.h revision 45008 
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    $Id: alias.h,v 1.9 1999/02/27 02:16:01 brian Exp $
11*/
12
13
14#ifndef _ALIAS_H_
15#define _ALIAS_H_
16
17#ifndef NULL
18#define NULL 0
19#endif
20
21/* Alias link representative (incomplete struct) */
22struct alias_link;
23
24/* External interfaces (API) to packet aliasing engine */
25
26/* Initialization and Control */
27    extern void
28    PacketAliasInit(void);
29
30    extern void
31    PacketAliasUninit(void);
32
33    extern void
34    PacketAliasSetAddress(struct in_addr);
35
36    extern unsigned int
37    PacketAliasSetMode(unsigned int, unsigned int);
38
39#ifndef NO_FW_PUNCH
40    extern void
41    PacketAliasSetFWBase(unsigned int, unsigned int);
42#endif
43
44/* Packet Handling */
45    extern int
46    PacketAliasIn(char *, int maxpacketsize);
47
48    extern int
49    PacketAliasOut(char *, int maxpacketsize);
50
51/* Port and Address Redirection */
52    extern struct alias_link *
53    PacketAliasRedirectPort(struct in_addr, u_short,
54                            struct in_addr, u_short,
55                            struct in_addr, u_short,
56                            u_char);
57
58    extern int
59    PacketAliasPptp(struct in_addr);
60
61
62    extern struct alias_link *
63    PacketAliasRedirectAddr(struct in_addr,
64                            struct in_addr);
65
66    extern void
67    PacketAliasRedirectDelete(struct alias_link *);
68
69/* Fragment Handling */
70    extern int
71    PacketAliasSaveFragment(char *);
72
73    extern char *
74    PacketAliasGetFragment(char *);
75
76    extern void
77    PacketAliasFragmentIn(char *, char *);
78
79/* Miscellaneous Functions */
80    extern void
81    PacketAliasSetTarget(struct in_addr addr);
82
83    extern int
84    PacketAliasCheckNewLink(void);
85
86    extern u_short
87    PacketAliasInternetChecksum(u_short *, int);
88
89/* Transparent Proxying */
90    extern int
91    PacketAliasProxyRule(const char *);
92
93
94/********************** Mode flags ********************/
95/* Set these flags using SetPacketAliasMode() */
96
97/* If PKT_ALIAS_LOG is set, a message will be printed to
98	/var/log/alias.log every time a link is created or deleted.  This
99	is useful for debugging */
100#define PKT_ALIAS_LOG 0x01
101
102/* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g.
103	to ftp, telnet or web servers will be prevented by the aliasing
104	mechanism.  */
105#define PKT_ALIAS_DENY_INCOMING 0x02
106
107/* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from
108	the same port as they originated on.  This allows eg rsh to work
109	*99% of the time*, but _not_ 100%.  (It will be slightly flakey
110	instead of not working at all.)  This mode bit is set by
111        PacketAliasInit(), so it is a default mode of operation. */
112#define PKT_ALIAS_SAME_PORTS 0x04
113
114/* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified
115	links (e.g. destination port and/or address is zero), the packet
116	aliasing engine will attempt to allocate a socket for the aliasing
117	port it chooses.  This will avoid interference with the host
118	machine.  Fully specified links do not require this.  This bit
119        is set after a call to PacketAliasInit(), so it is a default
120        mode of operation.*/
121#define PKT_ALIAS_USE_SOCKETS 0x08
122
123/* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with with
124	unregistered source addresses will be aliased (along with those
125	of the ppp host maching itself.  Private addresses are those
126        in the following ranges:
127		10.0.0.0     ->   10.255.255.255
128		172.16.0.0   ->   172.31.255.255
129		192.168.0.0  ->   192.168.255.255  */
130#define PKT_ALIAS_UNREGISTERED_ONLY 0x10
131
132/* If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
133	aliasing links will be reset whenever PacketAliasSetAddress()
134        changes the default aliasing address.  If the default aliasing
135        address is left unchanged by this functions call, then the
136        table of dynamic aliasing links will be left intact.  This
137        bit is set after a call to PacketAliasInit(). */
138#define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
139
140#ifndef NO_FW_PUNCH
141/* If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections
142   will create a 'hole' in the firewall to allow the transfers to
143   work.  Where (IPFW "line-numbers") the hole is created is
144   controlled by PacketAliasSetFWBase(base, size). The hole will be
145   attached to that particular alias_link, so when the link goes away
146   so do the hole.  */
147#define PKT_ALIAS_PUNCH_FW 0x40
148#endif
149
150/* If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
151      transparent proxying performed */
152#define PKT_ALIAS_PROXY_ONLY 0x40
153
154/* If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn()
155      and PacketAliasOut() are reversed */
156#define PKT_ALIAS_REVERSE 0x80
157
158/* Return Codes */
159#define PKT_ALIAS_ERROR -1
160#define PKT_ALIAS_OK 1
161#define PKT_ALIAS_IGNORED 2
162#define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
163#define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
164
165#endif
166/*lint -restore */
167