File

net/adns.lua @ 8706:e2919978673e

net.http: Fix parameter order to http request callbacks Commit e3b9dc9dd940 changed the parameter order in 2013, but did not update the names of the parameters in the callback function. Due to this inconsistency, 12df41a5a4b1 accidentally reversed the order when fixing the variable names without fixing where they are used. Additionally the documentation was incorrect (since 2013), and this has also now been fixed.
author Matthew Wild <mwild1@gmail.com>
date Wed, 04 Apr 2018 18:27:44 +0100
parent 8280:9ca0e3128b62
child 8555:4f0f5b49bb03
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-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 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 new_resolver = require "net.dns".resolver;

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

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

local function dummy_send(sock, data, i, j) return (j-i)+1; end

local _ENV = nil;

local async_resolver_methods = {};
local async_resolver_mt = { __index = async_resolver_methods };

local query_methods = {};
local query_mt = { __index = query_methods };

local function new_async_socket(sock, resolver)
	local peername = "<unknown>";
	local listener = {};
	local handler = {};
	local err;
	function listener.onincoming(conn, data)
		if data then
			resolver:feed(handler, data);
		end
	end
	function listener.ondisconnect(conn, err)
		if err then
			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
	end
	handler, err = server.wrapclient(sock, "dns", 53, listener);
	if not handler then
		return nil, err;
	end

	handler.settimeout = function () end
	handler.setsockname = function (_, ...) return sock:setsockname(...); end
	handler.setpeername = function (_, ...) peername = (...); local ret, err = sock:setpeername(...); _:set_send(dummy_send); return ret, err; end
	handler.connect = function (_, ...) return sock:connect(...) end
	--handler.send = function (_, data) _:write(data);  return _.sendbuffer and _.sendbuffer(); end
	handler.send = function (_, data)
		log("debug", "Sending DNS query to %s", peername);
		return sock:send(data);
	end
	return handler;
end

function async_resolver_methods:lookup(handler, qname, qtype, qclass)
	local resolver = self._resolver;
	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()));
				local ok, err = resolver:query(qname, qtype, qclass);
				if ok then
					coroutine.yield(setmetatable({ resolver, qclass or "IN", qtype or "A", qname, coroutine.running()}, query_mt)); -- Wait for reply
					log("debug", "Reply for %s (%s)", qname, tostring(coroutine.running()));
				end
				if ok then
					ok, err = pcall(handler, resolver:peek(qname, qtype, qclass));
				else
					log("error", "Error sending DNS query: %s", err);
					ok, err = pcall(handler, nil, err);
				end
				if not ok then
					log("error", "Error in DNS response handler: %s", tostring(err));
				end
			end)(resolver:peek(qname, qtype, qclass));
end

function query_methods:cancel(call_handler, reason)
	log("warn", "Cancelling DNS lookup for %s", tostring(self[4]));
	self[1].cancel(self[2], self[3], self[4], self[5], call_handler);
end

local function new_async_resolver()
	local resolver = new_resolver();
	resolver:socket_wrapper_set(new_async_socket);
	return setmetatable({ _resolver = resolver}, async_resolver_mt);
end

return {
	lookup = function (...)
		return new_async_resolver():lookup(...);
	end;
	resolver = new_async_resolver;
	new_async_socket = new_async_socket;
};