-- Prosody IM

-- Copyright (C) 2008-2009 Matthew Wild

-- Copyright (C) 2008-2009 Waqas Hussain

-- 

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local server = require "net.server";

local dns = require "net.dns";

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

local t_insert, t_remove = table.insert, table.remove;

local coroutine, tostring, pcall = coroutine, tostring, pcall;

module "adns"

function lookup(handler, qname, qtype, qclass)

	return coroutine.wrap(function (peek)

				if peek then

					log("debug", "Records for %s already cached, using those...", qname);

					handler(peek);

					return;

				end

				log("debug", "Records for %s not in cache, sending query (%s)...", qname, tostring(coroutine.running()));

				dns.query(qname, qtype, qclass);

				coroutine.yield({ qclass or "IN", qtype or "A", qname, coroutine.running()}); -- Wait for reply

				log("debug", "Reply for %s (%s)", qname, tostring(coroutine.running()));

				local ok, err = pcall(handler, dns.peek(qname, qtype, qclass));

				if not ok then

					log("error", "Error in DNS response handler: %s", tostring(err));

				end

			end)(dns.peek(qname, qtype, qclass));

end

function cancel(handle, call_handler)

	log("warn", "Cancelling DNS lookup for %s", tostring(handle[3]));

	dns.cancel(handle);

	if call_handler then

		coroutine.resume(handle[4]);

	end

end

function new_async_socket(sock, resolver)

	local peername = "<unknown>";

	local listener = {};

	local handler = {};

	function listener.onincoming(conn, data)

		dns.feed(handler, data);

	end

	function listener.ondisconnect(conn, err)

		log("warn", "DNS socket for %s disconnected: %s", peername, err);

		local servers = resolver.server;

		if resolver.socketset[conn] == resolver.best_server and resolver.best_server == #servers then

			log("error", "Exhausted all %d configured DNS servers, next lookup will try %s again", #servers, servers[1]);

		end

		resolver:servfail(conn); -- Let the magic commence

	end

	handler = server.wrapclient(sock, "dns", 53, listener);

	if not handler then

		log("warn", "handler is nil");

	end

	handler.settimeout = function () end

	handler.setsockname = function (_, ...) return sock:setsockname(...); end

	handler.setpeername = function (_, ...) peername = (...); local ret = sock:setpeername(...); _:set_send(sock.send); return ret; end

	return handler;

end

dns:socket_wrapper_set(new_async_socket);

return _M;