util.ip: New module containing IP related functions

util/ip.lua

@@ -0,0 +1,176 @@
+-- Prosody IM
+-- Copyright (C) 2008-2011 Florian Zeitz
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+
+local ip_methods = {};
+local ip_mt = { __index = function (ip, key) return (ip_methods[key])(ip); end,
+		__tostring = function (ip) return ip.addr; end,
+		__eq = function (ipA, ipB) return ipA.addr == ipB.addr; end};
+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" };
+
+local function new_ip(ipStr, proto)
+	if proto ~= "IPv4" and proto ~= "IPv6" then
+		return nil, "invalid protocol";
+	end
+
+	return setmetatable({ addr = ipStr, proto = proto }, ip_mt);
+end
+
+local function toBits(ip)
+	local result = "";
+	local fields = {};
+	if ip.proto == "IPv4" then
+		ip = ip.toV4mapped;
+	end
+	ip = (ip.addr):upper();
+	ip:gsub("([^:]*):?", function (c) fields[#fields + 1] = c end);
+	if not ip:match(":$") then fields[#fields] = nil; end
+	for i, field in ipairs(fields) do
+		if field:len() == 0 and i ~= 1 and i ~= #fields then
+			for i = 1, 16 * (9 - #fields) do
+				result = result .. "0";
+			end
+		else
+			for i = 1, 4 - field:len() do
+				result = result .. "0000";
+			end
+			for i = 1, field:len() do
+				result = result .. hex2bits[field:sub(i,i)];
+			end
+		end
+	end
+	return result;
+end
+
+local function commonPrefixLength(ipA, ipB)
+	ipA, ipB = toBits(ipA), toBits(ipB);
+	for i = 1, 128 do
+		if ipA:sub(i,i) ~= ipB:sub(i,i) then
+			return i-1;
+		end
+	end
+	return 128;
+end
+
+local function v4scope(ip)
+	local fields = {};
+	ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
+	-- Loopback:
+	if fields[1] == 127 then
+		return 0x2;
+	-- Link-local unicast:
+	elseif fields[1] == 169 and fields[2] == 254 then
+		return 0x2;
+	-- Site-local unicast:
+	elseif (fields[1] == 10) or (fields[1] == 192 and fields[2] == 168) or (fields[1] == 172 and fields[2] > 16) then
+		return 0x5;
+	-- Global unicast:
+	else
+		return 0xE;
+	end
+end
+
+local function v6scope(ip)
+	-- Loopback:
+	if ip:match("^[0:]*1$") then
+		return 0x2;
+	-- Link-local unicast:
+	elseif ip:match("^[Ff][Ee][89ABab]") then 
+		return 0x2;
+	-- Site-local unicast:
+	elseif ip:match("^[Ff][Ee][CcDdEeFf]") then
+		return 0x5;
+	-- Multicast:
+	elseif ip:match("^[Ff][Ff]") then
+		return tonumber("0x"..ip:sub(4,4));
+	-- Global unicast:
+	else
+		return 0xE;
+	end
+end
+
+local function label(ip)
+	if commonPrefixLength(ip, new_ip("::1", "IPv6")) == 128 then
+		return 0;
+	elseif commonPrefixLength(ip, new_ip("2002::", "IPv6")) >= 16 then
+		return 2;
+	elseif commonPrefixLength(ip, new_ip("::", "IPv6")) >= 96 then
+		return 3;
+	elseif commonPrefixLength(ip, new_ip("::ffff:0:0", "IPv6")) >= 96 then
+		return 4;
+	else
+		return 1;
+	end
+end
+
+local function precedence(ip)
+	if commonPrefixLength(ip, new_ip("::1", "IPv6")) == 128 then
+		return 50;
+	elseif commonPrefixLength(ip, new_ip("2002::", "IPv6")) >= 16 then
+		return 30;
+	elseif commonPrefixLength(ip, new_ip("::", "IPv6")) >= 96 then
+		return 20;
+	elseif commonPrefixLength(ip, new_ip("::ffff:0:0", "IPv6")) >= 96 then
+		return 10;
+	else
+		return 40;
+	end
+end
+
+local function toV4mapped(ip)
+	local fields = {};
+	local ret = "::ffff:";
+	ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);
+	ret = ret .. ("%02x"):format(fields[1]);
+	ret = ret .. ("%02x"):format(fields[2]);
+	ret = ret .. ":"
+	ret = ret .. ("%02x"):format(fields[3]);
+	ret = ret .. ("%02x"):format(fields[4]);
+	return new_ip(ret, "IPv6");
+end
+
+function ip_methods:toV4mapped()
+	if self.proto ~= "IPv4" then return nil, "No IPv4 address" end
+	local value = toV4mapped(self.addr);
+	self.toV4mapped = value;
+	return value;
+end
+
+function ip_methods:label()
+	local value;
+	if self.proto == "IPv4" then
+		value = label(self.toV4mapped);
+	else
+		value = label(self);
+	end
+	self.label = value;
+	return value;
+end
+
+function ip_methods:precedence()
+	local value;
+	if self.proto == "IPv4" then
+		value = precedence(self.toV4mapped);
+	else
+		value = precedence(self);
+	end
+	self.precedence = value;
+	return value;
+end
+
+function ip_methods:scope()
+	local value;
+	if self.proto == "IPv4" then
+		value = v4scope(self.addr);
+	else
+		value = v6scope(self.addr);
+	end
+	self.scope = value;
+	return value;
+end
+
+return {new_ip = new_ip,
+	commonPrefixLength = commonPrefixLength};