xref: /freebsd/sys/netinet/libalias/alias.h (revision ce834215a70ff69e7e222827437116eee2f9ac6f)
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 
11 
12 #ifndef _ALIAS_H_
13 #define _ALIAS_H_
14 
15 /* Alias link representativei (incomplete struct) */
16 struct alias_link;
17 
18 /* External interfaces (API) to packet aliasing engine */
19 extern int SaveFragmentPtr(char *);
20 extern char *GetNextFragmentPtr(char *);
21 extern void FragmentAliasIn(char *, char *);
22 extern int PacketAliasIn(char *, int maxpacketsize);
23 extern int PacketAliasOut(char *, int maxpacketsize);
24 extern int PacketAliasIn2(char *, struct in_addr, int maxpacketsize);
25 extern int PacketAliasOut2(char *, struct in_addr, int maxpacketsize);
26 extern void SetPacketAliasAddress(struct in_addr);
27 extern void InitPacketAlias(void);
28 extern void InitPacketAliasLog(void);
29 extern void UninitPacketAliasLog(void);
30 extern unsigned int SetPacketAliasMode(unsigned int, unsigned int);
31 extern struct alias_link *
32 PacketAliasRedirectPort(struct in_addr, u_short,
33                         struct in_addr, u_short,
34                         struct in_addr, u_short,
35                         u_char);
36 extern int
37 PacketAliasPermanentLink(struct in_addr, u_short,
38                          struct in_addr, u_short,
39                          u_short, u_char);
40 extern struct alias_link *
41 PacketAliasRedirectAddr(struct in_addr,
42                         struct in_addr);
43 void PacketAliasRedirectDelete(struct alias_link *);
44 
45 
46 /* InternetChecksum() is not specifically part of the
47    packet aliasing API, but is sometimes needed outside
48    the module. (~for instance, natd uses it to create
49    an ICMP error message when interface size is
50    exceeded.) */
51 
52 extern u_short InternetChecksum(u_short *, int);
53 
54 
55 /********************** Mode flags ********************/
56 /* Set these flags using SetPacketAliasMode() */
57 
58 /* If PKT_ALIAS_LOG is set, a message will be printed to
59 	/var/log/alias.log every time a link is created or deleted.  This
60 	is useful for debugging */
61 #define PKT_ALIAS_LOG 1
62 
63 /* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g.
64 	to ftp, telnet or web servers will be prevented by the aliasing
65 	mechanism.  */
66 #define PKT_ALIAS_DENY_INCOMING 2
67 
68 /* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from
69 	the same port as they originated on.  This allow eg rsh to work
70 	*99% of the time*, but _not_ 100%.  (It will be slightly flakey
71 	instead of not working at all.) */
72 #define PKT_ALIAS_SAME_PORTS 4
73 
74 /* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified
75 	links (e.g. destination port and/or address is zero), the packet
76 	aliasing engine will attempt to allocate a socket for the aliasing
77 	port it chooses.  This will avoid interference with the host
78 	machine.  Fully specified links do not require this.  */
79 #define PKT_ALIAS_USE_SOCKETS 8
80 
81 /* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with with
82 	unregistered source addresses will be aliased (along with those
83 	of the ppp host maching itself.  Private addresses are those
84         in the following ranges:
85 
86 		10.0.0.0     ->   10.255.255.255
87 		172.16.0.0   ->   172.31.255.255
88 		192.168.0.0  ->   192.168.255.255  */
89 #define PKT_ALIAS_UNREGISTERED_ONLY 16
90 
91 
92 
93 /* Return Codes */
94 #define PKT_ALIAS_ERROR -1
95 #define PKT_ALIAS_OK 1
96 #define PKT_ALIAS_IGNORED 2
97 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
98 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
99 #define PKT_ALIAS_NEW_LINK 5
100 
101 #endif
102 /*lint -restore */
103