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 not proto then
  16                 local sep = ipStr:match("^%x+(.)");
  17                 if sep == ":" then proto = "IPv6"
  18                 elseif sep == "." then proto = "IPv4"
  19                 end
  20                 if not proto then
  21                         return nil, "invalid address";
  22                 end
  23         elseif proto ~= "IPv4" and proto ~= "IPv6" then
  24                 return nil, "invalid protocol";
  25         end
  26         if proto == "IPv6" and ipStr:find('.', 1, true) then
  27                 local changed;
  28                 ipStr, changed = ipStr:gsub(":(%d+)%.(%d+)%.(%d+)%.(%d+)$", function(a,b,c,d)
  29                         return (":%04X:%04X"):format(a*256+b,c*256+d);
  30                 end);
  31                 if changed ~= 1 then return nil, "invalid-address"; end
  32         end
  33
  34         return setmetatable({ addr = ipStr, proto = proto }, ip_mt);
  35 end
  36
  37 local function toBits(ip)
  38         local result = "";
  39         local fields = {};
  40         if ip.proto == "IPv4" then
  41                 ip = ip.toV4mapped;
  42         end
  43         ip = (ip.addr):upper();
  44         ip:gsub("([^:]*):?", function (c) fields[#fields + 1] = c end);
  45         if not ip:match(":$") then fields[#fields] = nil; end
  46         for i, field in ipairs(fields) do
  47                 if field:len() == 0 and i ~= 1 and i ~= #fields then
  48                         for i = 1, 16 * (9 - #fields) do
  49                                 result = result .. "0";
  50                         end
  51                 else
  52                         for i = 1, 4 - field:len() do
  53                                 result = result .. "0000";
  54                         end
  55                         for i = 1, field:len() do
  56                                 result = result .. hex2bits[field:sub(i,i)];
  57                         end
  58                 end
  59         end
  60         return result;
  61 end
  62
  63 local function commonPrefixLength(ipA, ipB)
  64         ipA, ipB = toBits(ipA), toBits(ipB);
  65         for i = 1, 128 do
  66                 if ipA:sub(i,i) ~= ipB:sub(i,i) then
  67                         return i-1;
  68                 end
  69         end
  70         return 128;
  71 end
  72
  73 local function v4scope(ip)
  74         local fields = {};
  75         ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
  76         -- Loopback:
  77         if fields[1] == 127 then
  78                 return 0x2;
  79         -- Link-local unicast:
  80         elseif fields[1] == 169 and fields[2] == 254 then
  81                 return 0x2;
  82         -- Global unicast:
  83         else
  84                 return 0xE;
  85         end
  86 end
  87
  88 local function v6scope(ip)
  89         -- Loopback:
  90         if ip:match("^[0:]*1$") then
  91                 return 0x2;
  92         -- Link-local unicast:
  93         elseif ip:match("^[Ff][Ee][89ABab]") then
  94                 return 0x2;
  95         -- Site-local unicast:
  96         elseif ip:match("^[Ff][Ee][CcDdEeFf]") then
  97                 return 0x5;
  98         -- Multicast:
  99         elseif ip:match("^[Ff][Ff]") then
 100                 return tonumber("0x"..ip:sub(4,4));
 101         -- Global unicast:
 102         else
 103                 return 0xE;
 104         end
 105 end
 106
 107 local function label(ip)
 108         if commonPrefixLength(ip, new_ip("::1", "IPv6")) == 128 then
 109                 return 0;
 110         elseif commonPrefixLength(ip, new_ip("2002::", "IPv6")) >= 16 then
 111                 return 2;
 112         elseif commonPrefixLength(ip, new_ip("2001::", "IPv6")) >= 32 then
 113                 return 5;
 114         elseif commonPrefixLength(ip, new_ip("fc00::", "IPv6")) >= 7 then
 115                 return 13;
 116         elseif commonPrefixLength(ip, new_ip("fec0::", "IPv6")) >= 10 then
 117                 return 11;
 118         elseif commonPrefixLength(ip, new_ip("3ffe::", "IPv6")) >= 16 then
 119                 return 12;
 120         elseif commonPrefixLength(ip, new_ip("::", "IPv6")) >= 96 then
 121                 return 3;
 122         elseif commonPrefixLength(ip, new_ip("::ffff:0:0", "IPv6")) >= 96 then
 123                 return 4;
 124         else
 125                 return 1;
 126         end
 127 end
 128
 129 local function precedence(ip)
 130         if commonPrefixLength(ip, new_ip("::1", "IPv6")) == 128 then
 131                 return 50;
 132         elseif commonPrefixLength(ip, new_ip("2002::", "IPv6")) >= 16 then
 133                 return 30;
 134         elseif commonPrefixLength(ip, new_ip("2001::", "IPv6")) >= 32 then
 135                 return 5;
 136         elseif commonPrefixLength(ip, new_ip("fc00::", "IPv6")) >= 7 then
 137                 return 3;
 138         elseif commonPrefixLength(ip, new_ip("fec0::", "IPv6")) >= 10 then
 139                 return 1;
 140         elseif commonPrefixLength(ip, new_ip("3ffe::", "IPv6")) >= 16 then
 141                 return 1;
 142         elseif commonPrefixLength(ip, new_ip("::", "IPv6")) >= 96 then
 143                 return 1;
 144         elseif commonPrefixLength(ip, new_ip("::ffff:0:0", "IPv6")) >= 96 then
 145                 return 35;
 146         else
 147                 return 40;
 148         end
 149 end
 150
 151 local function toV4mapped(ip)
 152         local fields = {};
 153         local ret = "::ffff:";
 154         ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
 155         ret = ret .. ("%02x"):format(fields[1]);
 156         ret = ret .. ("%02x"):format(fields[2]);
 157         ret = ret .. ":"
 158         ret = ret .. ("%02x"):format(fields[3]);
 159         ret = ret .. ("%02x"):format(fields[4]);
 160         return new_ip(ret, "IPv6");
 161 end
 162
 163 function ip_methods:toV4mapped()
 164         if self.proto ~= "IPv4" then return nil, "No IPv4 address" end
 165         local value = toV4mapped(self.addr);
 166         self.toV4mapped = value;
 167         return value;
 168 end
 169
 170 function ip_methods:label()
 171         local value;
 172         if self.proto == "IPv4" then
 173                 value = label(self.toV4mapped);
 174         else
 175                 value = label(self);
 176         end
 177         self.label = value;
 178         return value;
 179 end
 180
 181 function ip_methods:precedence()
 182         local value;
 183         if self.proto == "IPv4" then
 184                 value = precedence(self.toV4mapped);
 185         else
 186                 value = precedence(self);
 187         end
 188         self.precedence = value;
 189         return value;
 190 end
 191
 192 function ip_methods:scope()
 193         local value;
 194         if self.proto == "IPv4" then
 195                 value = v4scope(self.addr);
 196         else
 197                 value = v6scope(self.addr);
 198         end
 199         self.scope = value;
 200         return value;
 201 end
 202
 203 function ip_methods:private()
 204         local private = self.scope ~= 0xE;
 205         if not private and self.proto == "IPv4" then
 206                 local ip = self.addr;
 207                 local fields = {};
 208                 ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
 209                 if fields[1] == 127 or fields[1] == 10 or (fields[1] == 192 and fields[2] == 168)
 210                 or (fields[1] == 172 and (fields[2] >= 16 or fields[2] <= 32)) then
 211                         private = true;
 212                 end
 213         end
 214         self.private = private;
 215         return private;
 216 end
 217
 218 return {new_ip = new_ip,
 219         commonPrefixLength = commonPrefixLength};