include/wvipaliaser.h

   1 /* -*- Mode: C++ -*-
   2  * Worldvisions Weaver Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  *
   5  */
   6 #ifndef __WVIPALIASER_H
   7 #define __WVIPALIASER_H
   8
   9 #include "wvinterface.h"
  10 #include "wvaddr.h"
  11
  12 /**
  13  * WvIPAliaser handles IP aliasing in the Linux kernel.  Multiple instances
  14  * of the object can be created, and they will share aliases between them.
  15  * Aliased addresses are only removed when all WvIPAliaser objects using
  16  * that address give it up.  (ie. the object is destroyed, or the Aliaser
  17  * is reconfigured without including that address)
  18  */
  19 class WvIPAliaser
  20 {
  21     struct Alias
  22     {
  23         int index, link_count;
  24         WvIPAddr ip;
  25
  26         Alias(const WvIPAddr &_ip);
  27         ~Alias();
  28     };
  29
  30     DeclareWvList(Alias);
  31
  32     static AliasList all_aliases;
  33     AliasList aliases;
  34     WvInterfaceDict interfaces;
  35
  36     WvIPAliaser::Alias *ipsearch(WvIPAliaser::AliasList &l,
  37                                  const WvIPAddr &ip);
  38
  39 public:
  40     WvIPAliaser();
  41     ~WvIPAliaser();
  42
  43     void dump();
  44
  45     /**
  46      * you must call start_edit() once, then add() any number of times, then
  47      * done_edit() once, to change your aliases.  The addresses add()ed
  48      * during the session become the _only_ ones that are aliases by this
  49      * WvIPAliaser instance.
  50      *
  51      * Why bother?  This way, WvIPAliaser can see all the desired aliases
  52      * when they are being changed, and only delete previously-added ones
  53      * if they are no longer used.  This is important, since if eg. Fast
  54      * Forward has an open connection through 1.2.3.4, and we want to add
  55      * 1.2.3.5 and delete 1.2.3.3, Fast Forward need not remember that it
  56      * was using 1.2.3.3 but 1.2.3.4 does not get deleted, even temporarily.
  57      *
  58      * If that was too confusing, just remember: call these functions in
  59      * the order they appear below, always.
  60      *
  61      * If add() returns true, then an interface was just created. If it returns
  62      * false, then that call made no changes.
  63      *
  64      * If done_edit() returns true, then one or more interfaces were just
  65      * destroyed. If it returns false, then that call made no changes.
  66      */
  67     void start_edit();
  68     bool add(const WvIPAddr &ip);
  69     bool done_edit();
  70 };
  71
  72
  73 #endif // __WVIPALIASER_H