alias.h revision 35314 
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 1.7 1998/01/16 12:56:07 bde 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 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
86/*
87   In version 2.2, the function names were rationalized
88   to all be of the form PacketAlias...  These are the
89   old function names for backwards compatibility
90*/
91extern int SaveFragmentPtr(char *);
92extern char *GetNextFragmentPtr(char *);
93extern void FragmentAliasIn(char *, char *);
94extern void SetPacketAliasAddress(struct in_addr);
95extern void InitPacketAlias(void);
96extern unsigned int SetPacketAliasMode(unsigned int, unsigned int);
97extern int PacketAliasIn2(char *, struct in_addr, int maxpacketsize);
98extern int PacketAliasOut2(char *, struct in_addr, int maxpacketsize);
99extern int
100PacketAliasPermanentLink(struct in_addr, u_short,
101                         struct in_addr, u_short,
102                         u_short, u_char);
103extern u_short InternetChecksum(u_short *, int);
104
105/* Obsolete constant */
106#define PKT_ALIAS_NEW_LINK 5
107
108/********************** Mode flags ********************/
109/* Set these flags using SetPacketAliasMode() */
110
111/* If PKT_ALIAS_LOG is set, a message will be printed to
112	/var/log/alias.log every time a link is created or deleted.  This
113	is useful for debugging */
114#define PKT_ALIAS_LOG 0x01
115
116/* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g.
117	to ftp, telnet or web servers will be prevented by the aliasing
118	mechanism.  */
119#define PKT_ALIAS_DENY_INCOMING 0x02
120
121/* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from
122	the same port as they originated on.  This allows eg rsh to work
123	*99% of the time*, but _not_ 100%.  (It will be slightly flakey
124	instead of not working at all.)  This mode bit is set by
125        PacketAliasInit(), so it is a default mode of operation. */
126#define PKT_ALIAS_SAME_PORTS 0x04
127
128/* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified
129	links (e.g. destination port and/or address is zero), the packet
130	aliasing engine will attempt to allocate a socket for the aliasing
131	port it chooses.  This will avoid interference with the host
132	machine.  Fully specified links do not require this.  This bit
133        is set after a call to PacketAliasInit(), so it is a default
134        mode of operation.*/
135#define PKT_ALIAS_USE_SOCKETS 0x08
136
137/* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with with
138	unregistered source addresses will be aliased (along with those
139	of the ppp host maching itself.  Private addresses are those
140        in the following ranges:
141
142		10.0.0.0     ->   10.255.255.255
143		172.16.0.0   ->   172.31.255.255
144		192.168.0.0  ->   192.168.255.255  */
145#define PKT_ALIAS_UNREGISTERED_ONLY 0x10
146
147/* If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
148	aliasing links will be reset whenever PacketAliasSetAddress()
149        changes the default aliasing address.  If the default aliasing
150        address is left unchanged by this functions call, then the
151        table of dynamic aliasing links will be left intact.  This
152        bit is set after a call to PacketAliasInit(). */
153#define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
154
155#ifndef NO_FW_PUNCH
156/* If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections
157   will create a 'hole' in the firewall to allow the transfers to
158   work.  Where (IPFW "line-numbers") the hole is created is
159   controlled by PacketAliasSetFWBase(base, size). The hole will be
160   attached to that particular alias_link, so when the link goes away
161   so do the hole.  */
162#define PKT_ALIAS_PUNCH_FW 0x40
163#endif
164
165/* Return Codes */
166#define PKT_ALIAS_ERROR -1
167#define PKT_ALIAS_OK 1
168#define PKT_ALIAS_IGNORED 2
169#define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
170#define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
171
172#endif
173/*lint -restore */
174