2 -- Copyright (C) 2008-2010 Matthew Wild
3 -- Copyright (C) 2008-2010 Waqas Hussain
5 -- This project is MIT/X11 licensed. Please see the
6 -- COPYING file in the source package for more information.
9 local server = require "net.server";
10 local dns = require "net.dns";
12 local log = require "util.logger".init("adns");
14 local t_insert, t_remove = table.insert, table.remove;
15 local coroutine, tostring, pcall = coroutine, tostring, pcall;
17 local function dummy_send(sock, data, i, j) return (j-i)+1; end
21 function lookup(handler, qname, qtype, qclass)
22 return coroutine.wrap(function (peek)
24 log("debug", "Records for %s already cached, using those...", qname);
28 log("debug", "Records for %s not in cache, sending query (%s)...", qname, tostring(coroutine.running()));
29 dns.query(qname, qtype, qclass);
30 coroutine.yield({ qclass or "IN", qtype or "A", qname, coroutine.running()}); -- Wait for reply
31 log("debug", "Reply for %s (%s)", qname, tostring(coroutine.running()));
32 local ok, err = pcall(handler, dns.peek(qname, qtype, qclass));
34 log("error", "Error in DNS response handler: %s", tostring(err));
36 end)(dns.peek(qname, qtype, qclass));
39 function cancel(handle, call_handler, reason)
40 log("warn", "Cancelling DNS lookup for %s", tostring(handle[3]));
41 dns.cancel(handle[1], handle[2], handle[3], handle[4], call_handler);
44 function new_async_socket(sock, resolver)
45 local peername = "<unknown>";
48 function listener.onincoming(conn, data)
50 dns.feed(handler, data);
53 function listener.ondisconnect(conn, err)
55 log("warn", "DNS socket for %s disconnected: %s", peername, err);
56 local servers = resolver.server;
57 if resolver.socketset[conn] == resolver.best_server and resolver.best_server == #servers then
58 log("error", "Exhausted all %d configured DNS servers, next lookup will try %s again", #servers, servers[1]);
61 resolver:servfail(conn); -- Let the magic commence
64 handler = server.wrapclient(sock, "dns", 53, listener);
66 log("warn", "handler is nil");
69 handler.settimeout = function () end
70 handler.setsockname = function (_, ...) return sock:setsockname(...); end
71 handler.setpeername = function (_, ...) peername = (...); local ret = sock:setpeername(...); _:set_send(dummy_send); return ret; end
72 handler.connect = function (_, ...) return sock:connect(...) end
73 --handler.send = function (_, data) _:write(data); return _.sendbuffer and _.sendbuffer(); end
74 handler.send = function (_, data) return sock:send(data); end
78 dns.socket_wrapper_set(new_async_socket);