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 net = require "util.net";
   9 local hex = require "util.hex";
  10
  11 local ip_methods = {};
  12
  13 local ip_mt = {
  14         __index = function (ip, key)
  15                 local method = ip_methods[key];
  16                 if not method then return nil; end
  17                 local ret = method(ip);
  18                 ip[key] = ret;
  19                 return ret;
  20         end,
  21         __tostring = function (ip) return ip.addr; end,
  22         __eq = function (ipA, ipB) return ipA.packed == ipB.packed; end
  23 };
  24
  25 local hex2bits = {
  26         ["0"] = "0000", ["1"] = "0001", ["2"] = "0010", ["3"] = "0011",
  27         ["4"] = "0100", ["5"] = "0101", ["6"] = "0110", ["7"] = "0111",
  28         ["8"] = "1000", ["9"] = "1001", ["A"] = "1010", ["B"] = "1011",
  29         ["C"] = "1100", ["D"] = "1101", ["E"] = "1110", ["F"] = "1111",
  30 };
  31
  32 local function new_ip(ipStr, proto)
  33         local zone;
  34         if (not proto or proto == "IPv6") and ipStr:find('%', 1, true) then
  35                 ipStr, zone = ipStr:match("^(.-)%%(.*)");
  36         end
  37
  38         local packed, err = net.pton(ipStr);
  39         if not packed then return packed, err end
  40         if proto == "IPv6" and #packed ~= 16 then
  41                 return nil, "invalid-ipv6";
  42         elseif proto == "IPv4" and #packed ~= 4 then
  43                 return nil, "invalid-ipv4";
  44         elseif not proto then
  45                 if #packed == 16 then
  46                         proto = "IPv6";
  47                 elseif #packed == 4 then
  48                         proto = "IPv4";
  49                 else
  50                         return nil, "unknown protocol";
  51                 end
  52         elseif proto ~= "IPv6" and proto ~= "IPv4" then
  53                 return nil, "invalid protocol";
  54         end
  55
  56         return setmetatable({ addr = ipStr, packed = packed, proto = proto, zone = zone }, ip_mt);
  57 end
  58
  59 function ip_methods:normal()
  60         return net.ntop(self.packed);
  61 end
  62
  63 function ip_methods.bits(ip)
  64         return hex.to(ip.packed):upper():gsub(".", hex2bits);
  65 end
  66
  67 function ip_methods.bits_full(ip)
  68         if ip.proto == "IPv4" then
  69                 ip = ip.toV4mapped;
  70         end
  71         return ip.bits;
  72 end
  73
  74 local match;
  75
  76 local function commonPrefixLength(ipA, ipB)
  77         ipA, ipB = ipA.bits_full, ipB.bits_full;
  78         for i = 1, 128 do
  79                 if ipA:sub(i,i) ~= ipB:sub(i,i) then
  80                         return i-1;
  81                 end
  82         end
  83         return 128;
  84 end
  85
  86 -- Instantiate once
  87 local loopback = new_ip("::1");
  88 local loopback4 = new_ip("127.0.0.0");
  89 local sixtofour = new_ip("2002::");
  90 local teredo = new_ip("2001::");
  91 local linklocal = new_ip("fe80::");
  92 local linklocal4 = new_ip("169.254.0.0");
  93 local uniquelocal = new_ip("fc00::");
  94 local sitelocal = new_ip("fec0::");
  95 local sixbone = new_ip("3ffe::");
  96 local defaultunicast = new_ip("::");
  97 local multicast = new_ip("ff00::");
  98 local ipv6mapped = new_ip("::ffff:0:0");
  99
 100 local function v4scope(ip)
 101         if match(ip, loopback4, 8) then
 102                 return 0x2;
 103         elseif match(ip, linklocal4) then
 104                 return 0x2;
 105         else -- Global unicast
 106                 return 0xE;
 107         end
 108 end
 109
 110 local function v6scope(ip)
 111         if ip == loopback then
 112                 return 0x2;
 113         elseif match(ip, linklocal, 10) then
 114                 return 0x2;
 115         elseif match(ip, sitelocal, 10) then
 116                 return 0x5;
 117         elseif match(ip, multicast, 10) then
 118                 return ip.packed:byte(2) % 0x10;
 119         else -- Global unicast
 120                 return 0xE;
 121         end
 122 end
 123
 124 local function label(ip)
 125         if ip == loopback then
 126                 return 0;
 127         elseif match(ip, sixtofour, 16) then
 128                 return 2;
 129         elseif match(ip, teredo, 32) then
 130                 return 5;
 131         elseif match(ip, uniquelocal, 7) then
 132                 return 13;
 133         elseif match(ip, sitelocal, 10) then
 134                 return 11;
 135         elseif match(ip, sixbone, 16) then
 136                 return 12;
 137         elseif match(ip, defaultunicast, 96) then
 138                 return 3;
 139         elseif match(ip, ipv6mapped, 96) then
 140                 return 4;
 141         else
 142                 return 1;
 143         end
 144 end
 145
 146 local function precedence(ip)
 147         if ip == loopback then
 148                 return 50;
 149         elseif match(ip, sixtofour, 16) then
 150                 return 30;
 151         elseif match(ip, teredo, 32) then
 152                 return 5;
 153         elseif match(ip, uniquelocal, 7) then
 154                 return 3;
 155         elseif match(ip, sitelocal, 10) then
 156                 return 1;
 157         elseif match(ip, sixbone, 16) then
 158                 return 1;
 159         elseif match(ip, defaultunicast, 96) then
 160                 return 1;
 161         elseif match(ip, ipv6mapped, 96) then
 162                 return 35;
 163         else
 164                 return 40;
 165         end
 166 end
 167
 168 function ip_methods:toV4mapped()
 169         if self.proto ~= "IPv4" then return nil, "No IPv4 address" end
 170         local value = new_ip("::ffff:" .. self.normal);
 171         return value;
 172 end
 173
 174 function ip_methods:label()
 175         if self.proto == "IPv4" then
 176                 return label(self.toV4mapped);
 177         else
 178                 return label(self);
 179         end
 180 end
 181
 182 function ip_methods:precedence()
 183         if self.proto == "IPv4" then
 184                 return precedence(self.toV4mapped);
 185         else
 186                 return precedence(self);
 187         end
 188 end
 189
 190 function ip_methods:scope()
 191         if self.proto == "IPv4" then
 192                 return v4scope(self);
 193         else
 194                 return v6scope(self);
 195         end
 196 end
 197
 198 local rfc1918_8 = new_ip("10.0.0.0");
 199 local rfc1918_12 = new_ip("172.16.0.0");
 200 local rfc1918_16 = new_ip("192.168.0.0");
 201 local rfc6598 = new_ip("100.64.0.0");
 202
 203 function ip_methods:private()
 204         local private = self.scope ~= 0xE;
 205         if not private and self.proto == "IPv4" then
 206                 return match(self, rfc1918_8, 8) or match(self, rfc1918_12, 12) or match(self, rfc1918_16, 16) or match(self, rfc6598, 10);
 207         end
 208         return private;
 209 end
 210
 211 local function parse_cidr(cidr)
 212         local bits;
 213         local ip_len = cidr:find("/", 1, true);
 214         if ip_len then
 215                 bits = tonumber(cidr:sub(ip_len+1, -1));
 216                 cidr = cidr:sub(1, ip_len-1);
 217         end
 218         return new_ip(cidr), bits;
 219 end
 220
 221 function match(ipA, ipB, bits)
 222         if not bits or bits >= 128 or ipB.proto == "IPv4" and bits >= 32 then
 223                 return ipA == ipB;
 224         elseif bits < 1 then
 225                 return true;
 226         end
 227         if ipA.proto ~= ipB.proto then
 228                 if ipA.proto == "IPv4" then
 229                         ipA = ipA.toV4mapped;
 230                 elseif ipB.proto == "IPv4" then
 231                         ipB = ipB.toV4mapped;
 232                         bits = bits + (128 - 32);
 233                 end
 234         end
 235         return ipA.bits:sub(1, bits) == ipB.bits:sub(1, bits);
 236 end
 237
 238 return {
 239         new_ip = new_ip,
 240         commonPrefixLength = commonPrefixLength,
 241         parse_cidr = parse_cidr,
 242         match = match,
 243 };