util/ip.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2008-2011 Florian Zeitz
   3 --
   4 -- This project is MIT/X11 licensed. Please see the
   5 -- COPYING file in the source package for more information.
   6 --
   7
   8 local ip_methods = {};
   9 local ip_mt = { __index = function (ip, key) return (ip_methods[key])(ip); end,
  10                 __tostring = function (ip) return ip.addr; end,
  11                 __eq = function (ipA, ipB) return ipA.addr == ipB.addr; end};
  12 local hex2bits = { ["0"] = "0000", ["1"] = "0001", ["2"] = "0010", ["3"] = "0011", ["4"] = "0100", ["5"] = "0101", ["6"] = "0110", ["7"] = "0111", ["8"] = "1000", ["9"] = "1001", ["A"] = "1010", ["B"] = "1011", ["C"] = "1100", ["D"] = "1101", ["E"] = "1110", ["F"] = "1111" };
  13
  14 local function new_ip(ipStr, proto)
  15         if proto ~= "IPv4" and proto ~= "IPv6" then
  16                 return nil, "invalid protocol";
  17         end
  18
  19         return setmetatable({ addr = ipStr, proto = proto }, ip_mt);
  20 end
  21
  22 local function toBits(ip)
  23         local result = "";
  24         local fields = {};
  25         if ip.proto == "IPv4" then
  26                 ip = ip.toV4mapped;
  27         end
  28         ip = (ip.addr):upper();
  29         ip:gsub("([^:]*):?", function (c) fields[#fields + 1] = c end);
  30         if not ip:match(":$") then fields[#fields] = nil; end
  31         for i, field in ipairs(fields) do
  32                 if field:len() == 0 and i ~= 1 and i ~= #fields then
  33                         for i = 1, 16 * (9 - #fields) do
  34                                 result = result .. "0";
  35                         end
  36                 else
  37                         for i = 1, 4 - field:len() do
  38                                 result = result .. "0000";
  39                         end
  40                         for i = 1, field:len() do
  41                                 result = result .. hex2bits[field:sub(i,i)];
  42                         end
  43                 end
  44         end
  45         return result;
  46 end
  47
  48 local function commonPrefixLength(ipA, ipB)
  49         ipA, ipB = toBits(ipA), toBits(ipB);
  50         for i = 1, 128 do
  51                 if ipA:sub(i,i) ~= ipB:sub(i,i) then
  52                         return i-1;
  53                 end
  54         end
  55         return 128;
  56 end
  57
  58 local function v4scope(ip)
  59         local fields = {};
  60         ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
  61         -- Loopback:
  62         if fields[1] == 127 then
  63                 return 0x2;
  64         -- Link-local unicast:
  65         elseif fields[1] == 169 and fields[2] == 254 then
  66                 return 0x2;
  67         -- Global unicast:
  68         else
  69                 return 0xE;
  70         end
  71 end
  72
  73 local function v6scope(ip)
  74         -- Loopback:
  75         if ip:match("^[0:]*1$") then
  76                 return 0x2;
  77         -- Link-local unicast:
  78         elseif ip:match("^[Ff][Ee][89ABab]") then
  79                 return 0x2;
  80         -- Site-local unicast:
  81         elseif ip:match("^[Ff][Ee][CcDdEeFf]") then
  82                 return 0x5;
  83         -- Multicast:
  84         elseif ip:match("^[Ff][Ff]") then
  85                 return tonumber("0x"..ip:sub(4,4));
  86         -- Global unicast:
  87         else
  88                 return 0xE;
  89         end
  90 end
  91
  92 local function label(ip)
  93         if commonPrefixLength(ip, new_ip("::1", "IPv6")) == 128 then
  94                 return 0;
  95         elseif commonPrefixLength(ip, new_ip("2002::", "IPv6")) >= 16 then
  96                 return 2;
  97         elseif commonPrefixLength(ip, new_ip("2001::", "IPv6")) >= 32 then
  98                 return 5;
  99         elseif commonPrefixLength(ip, new_ip("fc00::", "IPv6")) >= 7 then
 100                 return 13;
 101         elseif commonPrefixLength(ip, new_ip("fec0::", "IPv6")) >= 10 then
 102                 return 11;
 103         elseif commonPrefixLength(ip, new_ip("3ffe::", "IPv6")) >= 16 then
 104                 return 12;
 105         elseif commonPrefixLength(ip, new_ip("::", "IPv6")) >= 96 then
 106                 return 3;
 107         elseif commonPrefixLength(ip, new_ip("::ffff:0:0", "IPv6")) >= 96 then
 108                 return 4;
 109         else
 110                 return 1;
 111         end
 112 end
 113
 114 local function precedence(ip)
 115         if commonPrefixLength(ip, new_ip("::1", "IPv6")) == 128 then
 116                 return 50;
 117         elseif commonPrefixLength(ip, new_ip("2002::", "IPv6")) >= 16 then
 118                 return 30;
 119         elseif commonPrefixLength(ip, new_ip("2001::", "IPv6")) >= 32 then
 120                 return 5;
 121         elseif commonPrefixLength(ip, new_ip("fc00::", "IPv6")) >= 7 then
 122                 return 3;
 123         elseif commonPrefixLength(ip, new_ip("fec0::", "IPv6")) >= 10 then
 124                 return 1;
 125         elseif commonPrefixLength(ip, new_ip("3ffe::", "IPv6")) >= 16 then
 126                 return 1;
 127         elseif commonPrefixLength(ip, new_ip("::", "IPv6")) >= 96 then
 128                 return 1;
 129         elseif commonPrefixLength(ip, new_ip("::ffff:0:0", "IPv6")) >= 96 then
 130                 return 35;
 131         else
 132                 return 40;
 133         end
 134 end
 135
 136 local function toV4mapped(ip)
 137         local fields = {};
 138         local ret = "::ffff:";
 139         ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
 140         ret = ret .. ("%02x"):format(fields[1]);
 141         ret = ret .. ("%02x"):format(fields[2]);
 142         ret = ret .. ":"
 143         ret = ret .. ("%02x"):format(fields[3]);
 144         ret = ret .. ("%02x"):format(fields[4]);
 145         return new_ip(ret, "IPv6");
 146 end
 147
 148 function ip_methods:toV4mapped()
 149         if self.proto ~= "IPv4" then return nil, "No IPv4 address" end
 150         local value = toV4mapped(self.addr);
 151         self.toV4mapped = value;
 152         return value;
 153 end
 154
 155 function ip_methods:label()
 156         local value;
 157         if self.proto == "IPv4" then
 158                 value = label(self.toV4mapped);
 159         else
 160                 value = label(self);
 161         end
 162         self.label = value;
 163         return value;
 164 end
 165
 166 function ip_methods:precedence()
 167         local value;
 168         if self.proto == "IPv4" then
 169                 value = precedence(self.toV4mapped);
 170         else
 171                 value = precedence(self);
 172         end
 173         self.precedence = value;
 174         return value;
 175 end
 176
 177 function ip_methods:scope()
 178         local value;
 179         if self.proto == "IPv4" then
 180                 value = v4scope(self.addr);
 181         else
 182                 value = v6scope(self.addr);
 183         end
 184         self.scope = value;
 185         return value;
 186 end
 187
 188 return {new_ip = new_ip,
 189         commonPrefixLength = commonPrefixLength};