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 == ":" or (not(sep) and ipStr:sub(1,1) == ":") then
  18                         proto = "IPv6"
  19                 elseif sep == "." then
  20                         proto = "IPv4"
  21                 end
  22                 if not proto then
  23                         return nil, "invalid address";
  24                 end
  25         elseif proto ~= "IPv4" and proto ~= "IPv6" then
  26                 return nil, "invalid protocol";
  27         end
  28         if proto == "IPv6" and ipStr:find('.', 1, true) then
  29                 local changed;
  30                 ipStr, changed = ipStr:gsub(":(%d+)%.(%d+)%.(%d+)%.(%d+)$", function(a,b,c,d)
  31                         return (":%04X:%04X"):format(a*256+b,c*256+d);
  32                 end);
  33                 if changed ~= 1 then return nil, "invalid-address"; end
  34         end
  35
  36         return setmetatable({ addr = ipStr, proto = proto }, ip_mt);
  37 end
  38
  39 local function toBits(ip)
  40         local result = "";
  41         local fields = {};
  42         if ip.proto == "IPv4" then
  43                 ip = ip.toV4mapped;
  44         end
  45         ip = (ip.addr):upper();
  46         ip:gsub("([^:]*):?", function (c) fields[#fields + 1] = c end);
  47         if not ip:match(":$") then fields[#fields] = nil; end
  48         for i, field in ipairs(fields) do
  49                 if field:len() == 0 and i ~= 1 and i ~= #fields then
  50                         for i = 1, 16 * (9 - #fields) do
  51                                 result = result .. "0";
  52                         end
  53                 else
  54                         for i = 1, 4 - field:len() do
  55                                 result = result .. "0000";
  56                         end
  57                         for i = 1, field:len() do
  58                                 result = result .. hex2bits[field:sub(i,i)];
  59                         end
  60                 end
  61         end
  62         return result;
  63 end
  64
  65 local function commonPrefixLength(ipA, ipB)
  66         ipA, ipB = toBits(ipA), toBits(ipB);
  67         for i = 1, 128 do
  68                 if ipA:sub(i,i) ~= ipB:sub(i,i) then
  69                         return i-1;
  70                 end
  71         end
  72         return 128;
  73 end
  74
  75 local function v4scope(ip)
  76         local fields = {};
  77         ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
  78         -- Loopback:
  79         if fields[1] == 127 then
  80                 return 0x2;
  81         -- Link-local unicast:
  82         elseif fields[1] == 169 and fields[2] == 254 then
  83                 return 0x2;
  84         -- Global unicast:
  85         else
  86                 return 0xE;
  87         end
  88 end
  89
  90 local function v6scope(ip)
  91         -- Loopback:
  92         if ip:match("^[0:]*1$") then
  93                 return 0x2;
  94         -- Link-local unicast:
  95         elseif ip:match("^[Ff][Ee][89ABab]") then
  96                 return 0x2;
  97         -- Site-local unicast:
  98         elseif ip:match("^[Ff][Ee][CcDdEeFf]") then
  99                 return 0x5;
 100         -- Multicast:
 101         elseif ip:match("^[Ff][Ff]") then
 102                 return tonumber("0x"..ip:sub(4,4));
 103         -- Global unicast:
 104         else
 105                 return 0xE;
 106         end
 107 end
 108
 109 local function label(ip)
 110         if commonPrefixLength(ip, new_ip("::1", "IPv6")) == 128 then
 111                 return 0;
 112         elseif commonPrefixLength(ip, new_ip("2002::", "IPv6")) >= 16 then
 113                 return 2;
 114         elseif commonPrefixLength(ip, new_ip("2001::", "IPv6")) >= 32 then
 115                 return 5;
 116         elseif commonPrefixLength(ip, new_ip("fc00::", "IPv6")) >= 7 then
 117                 return 13;
 118         elseif commonPrefixLength(ip, new_ip("fec0::", "IPv6")) >= 10 then
 119                 return 11;
 120         elseif commonPrefixLength(ip, new_ip("3ffe::", "IPv6")) >= 16 then
 121                 return 12;
 122         elseif commonPrefixLength(ip, new_ip("::", "IPv6")) >= 96 then
 123                 return 3;
 124         elseif commonPrefixLength(ip, new_ip("::ffff:0:0", "IPv6")) >= 96 then
 125                 return 4;
 126         else
 127                 return 1;
 128         end
 129 end
 130
 131 local function precedence(ip)
 132         if commonPrefixLength(ip, new_ip("::1", "IPv6")) == 128 then
 133                 return 50;
 134         elseif commonPrefixLength(ip, new_ip("2002::", "IPv6")) >= 16 then
 135                 return 30;
 136         elseif commonPrefixLength(ip, new_ip("2001::", "IPv6")) >= 32 then
 137                 return 5;
 138         elseif commonPrefixLength(ip, new_ip("fc00::", "IPv6")) >= 7 then
 139                 return 3;
 140         elseif commonPrefixLength(ip, new_ip("fec0::", "IPv6")) >= 10 then
 141                 return 1;
 142         elseif commonPrefixLength(ip, new_ip("3ffe::", "IPv6")) >= 16 then
 143                 return 1;
 144         elseif commonPrefixLength(ip, new_ip("::", "IPv6")) >= 96 then
 145                 return 1;
 146         elseif commonPrefixLength(ip, new_ip("::ffff:0:0", "IPv6")) >= 96 then
 147                 return 35;
 148         else
 149                 return 40;
 150         end
 151 end
 152
 153 local function toV4mapped(ip)
 154         local fields = {};
 155         local ret = "::ffff:";
 156         ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
 157         ret = ret .. ("%02x"):format(fields[1]);
 158         ret = ret .. ("%02x"):format(fields[2]);
 159         ret = ret .. ":"
 160         ret = ret .. ("%02x"):format(fields[3]);
 161         ret = ret .. ("%02x"):format(fields[4]);
 162         return new_ip(ret, "IPv6");
 163 end
 164
 165 function ip_methods:toV4mapped()
 166         if self.proto ~= "IPv4" then return nil, "No IPv4 address" end
 167         local value = toV4mapped(self.addr);
 168         self.toV4mapped = value;
 169         return value;
 170 end
 171
 172 function ip_methods:label()
 173         local value;
 174         if self.proto == "IPv4" then
 175                 value = label(self.toV4mapped);
 176         else
 177                 value = label(self);
 178         end
 179         self.label = value;
 180         return value;
 181 end
 182
 183 function ip_methods:precedence()
 184         local value;
 185         if self.proto == "IPv4" then
 186                 value = precedence(self.toV4mapped);
 187         else
 188                 value = precedence(self);
 189         end
 190         self.precedence = value;
 191         return value;
 192 end
 193
 194 function ip_methods:scope()
 195         local value;
 196         if self.proto == "IPv4" then
 197                 value = v4scope(self.addr);
 198         else
 199                 value = v6scope(self.addr);
 200         end
 201         self.scope = value;
 202         return value;
 203 end
 204
 205 function ip_methods:private()
 206         local private = self.scope ~= 0xE;
 207         if not private and self.proto == "IPv4" then
 208                 local ip = self.addr;
 209                 local fields = {};
 210                 ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
 211                 if fields[1] == 127 or fields[1] == 10 or (fields[1] == 192 and fields[2] == 168)
 212                 or (fields[1] == 172 and (fields[2] >= 16 or fields[2] <= 32)) then
 213                         private = true;
 214                 end
 215         end
 216         self.private = private;
 217         return private;
 218 end
 219
 220 local function parse_cidr(cidr)
 221         local bits;
 222         local ip_len = cidr:find("/", 1, true);
 223         if ip_len then
 224                 bits = tonumber(cidr:sub(ip_len+1, -1));
 225                 cidr = cidr:sub(1, ip_len-1);
 226         end
 227         return new_ip(cidr), bits;
 228 end
 229
 230 local function match(ipA, ipB, bits)
 231         local common_bits = commonPrefixLength(ipA, ipB);
 232         if not bits then
 233                 return ipA == ipB;
 234         end
 235         if bits and ipB.proto == "IPv4" then
 236                 common_bits = common_bits - 96; -- v6 mapped addresses always share these bits
 237         end
 238         return common_bits >= bits;
 239 end
 240
 241 return {new_ip = new_ip,
 242         commonPrefixLength = commonPrefixLength,
 243         parse_cidr = parse_cidr,
 244         match=match};