-- 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 function new_ip(ipStr, proto)

	if not proto then

		local sep = ipStr:match("^%x+(.)");

		if sep == ":" or (not(sep) and ipStr:sub(1,1) == ":") then

			proto = "IPv6"

		elseif sep == "." then

			proto = "IPv4"

		end

		if not proto then

			return nil, "invalid address";

		end

	elseif proto ~= "IPv4" and proto ~= "IPv6" then

		return nil, "invalid protocol";

	end

	local zone;

	if proto == "IPv6" and ipStr:find('%', 1, true) then

		ipStr, zone = ipStr:match("^(.-)%%(.*)");

	end

	if proto == "IPv6" and ipStr:find('.', 1, true) then

		local changed;

		ipStr, changed = ipStr:gsub(":(%d+)%.(%d+)%.(%d+)%.(%d+)$", function(a,b,c,d)

			return (":%04X:%04X"):format(a*256+b,c*256+d);

		end);

		if changed ~= 1 then return nil, "invalid-address"; end

	end

	return setmetatable({ addr = ipStr, proto = proto, zone = zone }, 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 _ = 1, 16 * (9 - #fields) do

				result = result .. "0";

			end

		else

			for _ = 1, 4 - field:len() do

				result = result .. "0000";

			end

			for j = 1, field:len() do

				result = result .. hex2bits[field:sub(j, j)];

			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;

	-- 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("2001::", "IPv6")) >= 32 then

		return 5;

	elseif commonPrefixLength(ip, new_ip("fc00::", "IPv6")) >= 7 then

		return 13;

	elseif commonPrefixLength(ip, new_ip("fec0::", "IPv6")) >= 10 then

		return 11;

	elseif commonPrefixLength(ip, new_ip("3ffe::", "IPv6")) >= 16 then

		return 12;

	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("2001::", "IPv6")) >= 32 then

		return 5;

	elseif commonPrefixLength(ip, new_ip("fc00::", "IPv6")) >= 7 then

		return 3;

	elseif commonPrefixLength(ip, new_ip("fec0::", "IPv6")) >= 10 then

		return 1;

	elseif commonPrefixLength(ip, new_ip("3ffe::", "IPv6")) >= 16 then

		return 1;

	elseif commonPrefixLength(ip, new_ip("::", "IPv6")) >= 96 then

		return 1;

	elseif commonPrefixLength(ip, new_ip("::ffff:0:0", "IPv6")) >= 96 then

		return 35;

	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

function ip_methods:private()

	local private = self.scope ~= 0xE;

	if not private and self.proto == "IPv4" then

		local ip = self.addr;

		local fields = {};

		ip:gsub("([^.]*).?", function (c) fields[#fields + 1] = tonumber(c) end);

		if fields[1] == 127 or fields[1] == 10 or (fields[1] == 192 and fields[2] == 168)

		or (fields[1] == 172 and (fields[2] >= 16 or fields[2] <= 32)) then

			private = true;

		end

	end

	self.private = private;

	return private;

end

local function parse_cidr(cidr)

	local bits;

	local ip_len = cidr:find("/", 1, true);

	if ip_len then

		bits = tonumber(cidr:sub(ip_len+1, -1));

		cidr = cidr:sub(1, ip_len-1);

	end

	return new_ip(cidr), bits;

end

local function match(ipA, ipB, bits)

	local common_bits = commonPrefixLength(ipA, ipB);

	if bits and ipB.proto == "IPv4" then

		common_bits = common_bits - 96; -- v6 mapped addresses always share these bits

	end

	return common_bits >= (bits or 128);

end

return {new_ip = new_ip,

	commonPrefixLength = commonPrefixLength,

	parse_cidr = parse_cidr,

	match=match};