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