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) */ 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 #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 */ 91 extern int SaveFragmentPtr(char *); 92 extern char *GetNextFragmentPtr(char *); 93 extern void FragmentAliasIn(char *, char *); 94 extern void SetPacketAliasAddress(struct in_addr); 95 extern void InitPacketAlias(void); 96 extern unsigned int SetPacketAliasMode(unsigned int, unsigned int); 97 extern int PacketAliasIn2(char *, struct in_addr, int maxpacketsize); 98 extern int PacketAliasOut2(char *, struct in_addr, int maxpacketsize); 99 extern int 100 PacketAliasPermanentLink(struct in_addr, u_short, 101 struct in_addr, u_short, 102 u_short, u_char); 103 extern 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