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-- 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
handler.connect = function (_, ...) return sock:connect(...) end
handler.send = function (_, data) _:write(data); return _.sendbuffer and _.sendbuffer(); end
return handler;
end
dns:socket_wrapper_set(new_async_socket);
return _M;
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