File

net/adns.lua @ 870:4fd5d8f1657c

net.adns: Add helper module for performing non-blocking DNS lookups
author Matthew Wild <mwild1@gmail.com>
date Wed, 04 Mar 2009 12:59:35 +0000
child 871:642af1bdf74e
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local server = require "net.server";
local dns = require "net.dns2";

local log = require "util.logger".init("adns");

local coroutine, tostring = coroutine, tostring;

module "adns"

function lookup(handler, qname, qtype, qclass)
	return dns.peek(qname, qtype, qclass) or
		coroutine.wrap(function ()
				log("debug", "Records for "..qname.." not in cache, sending query (%s)...", tostring(coroutine.running()));
				dns.query(qname, qtype, qclass);
				coroutine.yield(nil); -- Wait for reply
				log("debug", "Reply for "..qname.." (%s)", tostring(coroutine.running()));
				handler(dns.peek(qname, qtype, qclass));
			end)();
end

function new_async_socket(sock)
	local newconn = {};
	local listener = {};
	function listener.incoming(conn, data)
		dns.feed(sock, data);
	end
	function listener.disconnect()
	end
	newconn.handler, newconn._socket = server.wrapclient(sock, "dns", 53, listener);
	newconn.handler.settimeout = function () end
	newconn.handler.setsockname = function (_, ...) return sock:setsockname(...); end
	newconn.handler.setpeername = function (_, ...) return sock:setpeername(...); end
	newconn.handler.connect = function (_, ...) return sock:connect(...) end	
	newconn.handler.send = function (_, data) return _.write(data) end	
	return newconn.handler;
end

dns:socket_wrapper_set(new_async_socket);