alias.h revision 32560 
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    $Id$
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    extern void
40    PacketAliasSetFWBase(unsigned int, unsigned int);
41
42/* Packet Handling */
43    extern int
44    PacketAliasIn(char *, int maxpacketsize);
45
46    extern int
47    PacketAliasOut(char *, int maxpacketsize);
48
49/* Port and Address Redirection */
50    extern struct alias_link *
51    PacketAliasRedirectPort(struct in_addr, u_short,
52                            struct in_addr, u_short,
53                            struct in_addr, u_short,
54                            u_char);
55
56    extern struct alias_link *
57    PacketAliasRedirectAddr(struct in_addr,
58                            struct in_addr);
59
60    extern void
61    PacketAliasRedirectDelete(struct alias_link *);
62
63/* Fragment Handling */
64    extern int
65    PacketAliasSaveFragment(char *);
66
67    extern char *
68    PacketAliasGetFragment(char *);
69
70    extern void
71    PacketAliasFragmentIn(char *, char *);
72
73/* Miscellaneous Functions */
74    extern void
75    PacketAliasSetTarget(struct in_addr addr);
76
77    extern int
78    PacketAliasCheckNewLink(void);
79
80    extern u_short
81    PacketAliasInternetChecksum(u_short *, int);
82
83
84/*
85   In version 2.2, the function names were rationalized
86   to all be of the form PacketAlias...  These are the
87   old function names for backwards compatibility
88*/
89extern int SaveFragmentPtr(char *);
90extern char *GetNextFragmentPtr(char *);
91extern void FragmentAliasIn(char *, char *);
92extern void SetPacketAliasAddress(struct in_addr);
93extern void InitPacketAlias(void);
94extern unsigned int SetPacketAliasMode(unsigned int, unsigned int);
95extern int PacketAliasIn2(char *, struct in_addr, int maxpacketsize);
96extern int PacketAliasOut2(char *, struct in_addr, int maxpacketsize);
97extern int
98PacketAliasPermanentLink(struct in_addr, u_short,
99                         struct in_addr, u_short,
100                         u_short, u_char);
101extern u_short InternetChecksum(u_short *, int);
102
103/* Obsolete constant */
104#define PKT_ALIAS_NEW_LINK 5
105
106/********************** Mode flags ********************/
107/* Set these flags using SetPacketAliasMode() */
108
109/* If PKT_ALIAS_LOG is set, a message will be printed to
110	/var/log/alias.log every time a link is created or deleted.  This
111	is useful for debugging */
112#define PKT_ALIAS_LOG 0x01
113
114/* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g.
115	to ftp, telnet or web servers will be prevented by the aliasing
116	mechanism.  */
117#define PKT_ALIAS_DENY_INCOMING 0x02
118
119/* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from
120	the same port as they originated on.  This allows eg rsh to work
121	*99% of the time*, but _not_ 100%.  (It will be slightly flakey
122	instead of not working at all.)  This mode bit is set by
123        PacketAliasInit(), so it is a default mode of operation. */
124#define PKT_ALIAS_SAME_PORTS 0x04
125
126/* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified
127	links (e.g. destination port and/or address is zero), the packet
128	aliasing engine will attempt to allocate a socket for the aliasing
129	port it chooses.  This will avoid interference with the host
130	machine.  Fully specified links do not require this.  This bit
131        is set after a call to PacketAliasInit(), so it is a default
132        mode of operation.*/
133#define PKT_ALIAS_USE_SOCKETS 0x08
134
135/* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with with
136	unregistered source addresses will be aliased (along with those
137	of the ppp host maching itself.  Private addresses are those
138        in the following ranges:
139
140		10.0.0.0     ->   10.255.255.255
141		172.16.0.0   ->   172.31.255.255
142		192.168.0.0  ->   192.168.255.255  */
143#define PKT_ALIAS_UNREGISTERED_ONLY 0x10
144
145/* If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
146	aliasing links will be reset whenever PacketAliasSetAddress()
147        changes the default aliasing address.  If the default aliasing
148        address is left unchanged by this functions call, then the
149        table of dynamic aliasing links will be left intact.  This
150        bit is set after a call to PacketAliasInit(). */
151#define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
152
153/* If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections
154   will create a 'hole' in the firewall to allow the transfers to
155   work.  Where (IPFW "line-numbers") the hole is created is
156   controlled by PacketAliasSetFWBase(base, size). The hole will be
157   attached to that particular alias_link, so when the link goes away
158   so do the hole.  */
159#define PKT_ALIAS_PUNCH_FW 0x40
160
161/* Return Codes */
162#define PKT_ALIAS_ERROR -1
163#define PKT_ALIAS_OK 1
164#define PKT_ALIAS_IGNORED 2
165#define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
166#define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
167
168#endif
169/*lint -restore */
170