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