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 $FreeBSD$ 11 */ 12 13 14 #ifndef _ALIAS_H_ 15 #define _ALIAS_H_ 16 17 /* Alias link representative (incomplete struct) */ 18 struct alias_link; 19 20 /* External interfaces (API) to packet aliasing engine */ 21 22 /* Initialization and Control */ 23 extern void 24 PacketAliasInit(void); 25 26 extern void 27 PacketAliasUninit(void); 28 29 extern void 30 PacketAliasSetAddress(struct in_addr); 31 32 extern unsigned int 33 PacketAliasSetMode(unsigned int, unsigned int); 34 35 #ifndef NO_FW_PUNCH 36 extern void 37 PacketAliasSetFWBase(unsigned int, unsigned int); 38 #endif 39 40 /* Packet Handling */ 41 extern int 42 PacketAliasIn(char *, int maxpacketsize); 43 44 extern int 45 PacketAliasOut(char *, int maxpacketsize); 46 47 /* Port and Address Redirection */ 48 extern struct alias_link * 49 PacketAliasRedirectPort(struct in_addr, u_short, 50 struct in_addr, u_short, 51 struct in_addr, u_short, 52 u_char); 53 54 extern int 55 PacketAliasPptp(struct in_addr); 56 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 /* Transparent Proxying */ 86 extern int 87 PacketAliasProxyRule(const char *); 88 89 90 /********************** Mode flags ********************/ 91 /* Set these flags using PacketAliasSetMode() */ 92 93 /* If PKT_ALIAS_LOG is set, a message will be printed to 94 /var/log/alias.log every time a link is created or deleted. This 95 is useful for debugging */ 96 #define PKT_ALIAS_LOG 0x01 97 98 /* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. 99 to ftp, telnet or web servers will be prevented by the aliasing 100 mechanism. */ 101 #define PKT_ALIAS_DENY_INCOMING 0x02 102 103 /* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from 104 the same port as they originated on. This allows e.g. rsh to work 105 *99% of the time*, but _not_ 100%. (It will be slightly flakey 106 instead of not working at all.) This mode bit is set by 107 PacketAliasInit(), so it is a default mode of operation. */ 108 #define PKT_ALIAS_SAME_PORTS 0x04 109 110 /* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified 111 links (e.g. destination port and/or address is zero), the packet 112 aliasing engine will attempt to allocate a socket for the aliasing 113 port it chooses. This will avoid interference with the host 114 machine. Fully specified links do not require this. This bit 115 is set after a call to PacketAliasInit(), so it is a default 116 mode of operation.*/ 117 #define PKT_ALIAS_USE_SOCKETS 0x08 118 119 /* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with 120 unregistered source addresses will be aliased (along with those 121 of the ppp host maching itself. Private addresses are those 122 in the following ranges: 123 10.0.0.0 -> 10.255.255.255 124 172.16.0.0 -> 172.31.255.255 125 192.168.0.0 -> 192.168.255.255 */ 126 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10 127 128 /* If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic 129 aliasing links will be reset whenever PacketAliasSetAddress() 130 changes the default aliasing address. If the default aliasing 131 address is left unchanged by this functions call, then the 132 table of dynamic aliasing links will be left intact. This 133 bit is set after a call to PacketAliasInit(). */ 134 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20 135 136 #ifndef NO_FW_PUNCH 137 /* If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections 138 will create a 'hole' in the firewall to allow the transfers to 139 work. Where (IPFW "line-numbers") the hole is created is 140 controlled by PacketAliasSetFWBase(base, size). The hole will be 141 attached to that particular alias_link, so when the link goes away 142 so do the hole. */ 143 #define PKT_ALIAS_PUNCH_FW 0x100 144 #endif 145 146 /* If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only 147 transparent proxying performed */ 148 #define PKT_ALIAS_PROXY_ONLY 0x40 149 150 /* If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() 151 and PacketAliasOut() are reversed */ 152 #define PKT_ALIAS_REVERSE 0x80 153 154 /* Return Codes */ 155 #define PKT_ALIAS_ERROR -1 156 #define PKT_ALIAS_OK 1 157 #define PKT_ALIAS_IGNORED 2 158 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3 159 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4 160 161 #endif 162 /*lint -restore */ 163