linuxstreams/wvipaliaser.cc

   1 /*
   2  * Worldvisions Weaver Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  *
   5  * WvIPAliaser handles IP aliasing in the Linux kernel.  See wvipaliaser.h.
   6  */
   7 #include "wvipaliaser.h"
   8 #include "wvinterface.h"
   9 #include <assert.h>
  10
  11
  12 WvIPAliaser::AliasList WvIPAliaser::all_aliases;
  13
  14
  15
  16 ///////////////////////////////////// WvIPAliaser::Alias
  17
  18
  19
  20 WvIPAliaser::Alias::Alias(const WvIPAddr &_ip) : ip(_ip)
  21 {
  22     WvIPAddr noip;
  23     WvIPNet nonet(noip, noip);
  24     link_count = 0;
  25
  26     for (index = 0; index < 256; index++)
  27     {
  28         WvInterface i(WvString("lo:wv%s", index));
  29
  30         if (!i.isup() || i.ipaddr() == nonet) // not in use yet!
  31         {
  32             i.setipaddr(ip);
  33             i.up(true);
  34             if (WvIPAddr(i.ipaddr()) != ip)
  35             {
  36                 // no permission, most likely.
  37                 index = -1;
  38                 i.up(false);
  39             }
  40             return;
  41         }
  42
  43         if (i.isup() && WvIPNet(i.ipaddr(),32) == ip)
  44         {
  45             // a bit weird... this alias already has the right address.
  46             // Keep it.
  47             return;
  48         }
  49     }
  50
  51     // got through all possible names without a free one?  Weird!
  52     index = -1;
  53 }
  54
  55
  56 WvIPAliaser::Alias::~Alias()
  57 {
  58     if (index >= 0)
  59     {
  60         WvInterface i(WvString("lo:wv%s", index));
  61         // i.setipaddr(WvIPAddr()); // not necessary in recent kernels
  62         i.up(false);
  63     }
  64 }
  65
  66
  67
  68 //////////////////////////////////// WvIPAliaser
  69
  70
  71
  72 WvIPAliaser::WvIPAliaser() : interfaces()
  73 {
  74     // nothing to do
  75 }
  76
  77
  78 WvIPAliaser::~WvIPAliaser()
  79 {
  80     // clear the alias list
  81     start_edit();
  82     done_edit();
  83 }
  84
  85
  86 void WvIPAliaser::start_edit()
  87 {
  88     AliasList::Iter i(aliases);
  89
  90     #ifndef NDEBUG
  91     AliasList::Iter i_all(all_aliases);
  92     #endif
  93
  94     interfaces.update();
  95
  96     for (i.rewind(); i.next(); )
  97     {
  98         assert(i_all.find(i.ptr()));
  99
 100         // the global alias entry goes down by one
 101         i().link_count--;
 102     }
 103
 104     // empty out the local list
 105     aliases.zap();
 106 }
 107
 108
 109 WvIPAliaser::Alias *WvIPAliaser::ipsearch(WvIPAliaser::AliasList &l,
 110                                           const WvIPAddr &ip)
 111 {
 112     AliasList::Iter i(l);
 113
 114     for (i.rewind(); i.next(); )
 115     {
 116         if (i->ip == WvIPAddr(ip))
 117             return i.ptr();
 118     }
 119
 120     return NULL;
 121 }
 122
 123
 124 bool WvIPAliaser::add(const WvIPAddr &ip)
 125 {
 126     Alias *a;
 127
 128     if (WvIPAddr(ip) == WvIPAddr() || ipsearch(aliases, ip))
 129         return false;     // already done.
 130
 131     // If the alias is already a local address, there is no need for an alias.
 132     // We have to be careful that we don't find an existing alias as the
 133     // local interface.  Otherwise, we'll toggle that alias on and off.
 134     WvString ifc(interfaces.islocal(WvIPAddr(ip)));
 135     if (!!ifc && !strchr(ifc, ':')) // Make sure it is a real interface
 136         return false;
 137
 138     a = ipsearch(all_aliases, ip);
 139     if (a)
 140     {
 141         // It's already in the global list, so we add its entry to
 142         // our list and increase the link count.
 143         aliases.append(a, false);
 144         a->link_count++;
 145         return false;
 146     }
 147     else
 148     {
 149         // It's not there, so we add a new alias to the global list and
 150         // our local list.
 151         a = new Alias(ip);
 152         aliases.append(a, false);
 153         all_aliases.append(a, true);
 154         a->link_count++;
 155         return true;
 156     }
 157 }
 158
 159
 160 bool WvIPAliaser::done_edit()
 161 {
 162     bool any_change=false;
 163     AliasList::Iter i(all_aliases);
 164
 165     i.rewind(); i.next();
 166     while (i.cur())
 167     {
 168         Alias &a = *i;
 169         if (!a.link_count) {
 170             i.unlink();
 171             any_change = true;
 172         } else
 173             i.next();
 174     }
 175
 176     return any_change;
 177 }
 178
 179
 180 void WvIPAliaser::dump()
 181 {
 182     {
 183         WvLog log("local aliases");
 184         AliasList::Iter i(aliases);
 185         for (i.rewind(); i.next(); )
 186         {
 187             Alias &a = *i;
 188             log("#%s = lo:wv%s: %s (%s links)\n",
 189                 a.index, a.index, a.ip, a.link_count);
 190         }
 191         log(".\n");
 192     }
 193
 194     {
 195         WvLog log("global aliases");
 196         AliasList::Iter i(all_aliases);
 197         for (i.rewind(); i.next(); )
 198         {
 199             Alias &a = *i;
 200             log("#%s = lo:wv%s: %s (%s links)\n",
 201                 a.index, a.index, a.ip, a.link_count);
 202         }
 203         log(".\n.\n");
 204     }
 205 }