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) */ 22 struct 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 */ 89 extern int SaveFragmentPtr(char *); 90 extern char *GetNextFragmentPtr(char *); 91 extern void FragmentAliasIn(char *, char *); 92 extern void SetPacketAliasAddress(struct in_addr); 93 extern void InitPacketAlias(void); 94 extern unsigned int SetPacketAliasMode(unsigned int, unsigned int); 95 extern int PacketAliasIn2(char *, struct in_addr, int maxpacketsize); 96 extern int PacketAliasOut2(char *, struct in_addr, int maxpacketsize); 97 extern int 98 PacketAliasPermanentLink(struct in_addr, u_short, 99 struct in_addr, u_short, 100 u_short, u_char); 101 extern 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