alias/alias.h

   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 1.1.1.1 2000/01/11 01:48:42 wsanchez 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 int
  59     PacketAliasPptp(struct in_addr);
  60
  61
  62     extern struct alias_link *
  63     PacketAliasRedirectAddr(struct in_addr,
  64                             struct in_addr);
  65
  66     extern void
  67     PacketAliasRedirectDelete(struct alias_link *);
  68
  69 /* Fragment Handling */
  70     extern int
  71     PacketAliasSaveFragment(char *);
  72
  73     extern char *
  74     PacketAliasGetFragment(char *);
  75
  76     extern void
  77     PacketAliasFragmentIn(char *, char *);
  78
  79 /* Miscellaneous Functions */
  80     extern void
  81     PacketAliasSetTarget(struct in_addr addr);
  82
  83     extern int
  84     PacketAliasCheckNewLink(void);
  85
  86     extern u_short
  87     PacketAliasInternetChecksum(u_short *, int);
  88
  89 /* Transparent Proxying */
  90     extern int
  91     PacketAliasProxyRule(const char *);
  92
  93
  94 /********************** Mode flags ********************/
  95 /* Set these flags using SetPacketAliasMode() */
  96
  97 /* If PKT_ALIAS_LOG is set, a message will be printed to
  98         /var/log/alias.log every time a link is created or deleted.  This
  99         is useful for debugging */
 100 #define PKT_ALIAS_LOG 0x01
 101
 102 /* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g.
 103         to ftp, telnet or web servers will be prevented by the aliasing
 104         mechanism.  */
 105 #define PKT_ALIAS_DENY_INCOMING 0x02
 106
 107 /* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from
 108         the same port as they originated on.  This allows eg rsh to work
 109         *99% of the time*, but _not_ 100%.  (It will be slightly flakey
 110         instead of not working at all.)  This mode bit is set by
 111         PacketAliasInit(), so it is a default mode of operation. */
 112 #define PKT_ALIAS_SAME_PORTS 0x04
 113
 114 /* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified
 115         links (e.g. destination port and/or address is zero), the packet
 116         aliasing engine will attempt to allocate a socket for the aliasing
 117         port it chooses.  This will avoid interference with the host
 118         machine.  Fully specified links do not require this.  This bit
 119         is set after a call to PacketAliasInit(), so it is a default
 120         mode of operation.*/
 121 #define PKT_ALIAS_USE_SOCKETS 0x08
 122
 123 /* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with with
 124         unregistered source addresses will be aliased (along with those
 125         of the ppp host maching itself.  Private addresses are those
 126         in the following ranges:
 127                 10.0.0.0     ->   10.255.255.255
 128                 172.16.0.0   ->   172.31.255.255
 129                 192.168.0.0  ->   192.168.255.255  */
 130 #define PKT_ALIAS_UNREGISTERED_ONLY 0x10
 131
 132 /* If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
 133         aliasing links will be reset whenever PacketAliasSetAddress()
 134         changes the default aliasing address.  If the default aliasing
 135         address is left unchanged by this functions call, then the
 136         table of dynamic aliasing links will be left intact.  This
 137         bit is set after a call to PacketAliasInit(). */
 138 #define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
 139
 140 #ifndef NO_FW_PUNCH
 141 /* If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections
 142    will create a 'hole' in the firewall to allow the transfers to
 143    work.  Where (IPFW "line-numbers") the hole is created is
 144    controlled by PacketAliasSetFWBase(base, size). The hole will be
 145    attached to that particular alias_link, so when the link goes away
 146    so do the hole.  */
 147 #define PKT_ALIAS_PUNCH_FW 0x40
 148 #endif
 149
 150 /* If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
 151       transparent proxying performed */
 152 #define PKT_ALIAS_PROXY_ONLY 0x40
 153
 154 /* If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn()
 155       and PacketAliasOut() are reversed */
 156 #define PKT_ALIAS_REVERSE 0x80
 157
 158 /* Return Codes */
 159 #define PKT_ALIAS_ERROR -1
 160 #define PKT_ALIAS_OK 1
 161 #define PKT_ALIAS_IGNORED 2
 162 #define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
 163 #define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
 164
 165 #endif
 166 /*lint -restore */