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)
40 log("warn", "Cancelling DNS lookup for %s", tostring(handle[3]));
43 coroutine.resume(handle[4]);
47 function new_async_socket(sock, resolver)
48 local peername = "<unknown>";
51 function listener.onincoming(conn, data)
53 dns.feed(handler, data);
56 function listener.ondisconnect(conn, err)
58 log("warn", "DNS socket for %s disconnected: %s", peername, err);
59 local servers = resolver.server;
60 if resolver.socketset[conn] == resolver.best_server and resolver.best_server == #servers then
61 log("error", "Exhausted all %d configured DNS servers, next lookup will try %s again", #servers, servers[1]);
64 resolver:servfail(conn); -- Let the magic commence
67 handler = server.wrapclient(sock, "dns", 53, listener);
69 log("warn", "handler is nil");
72 handler.settimeout = function () end
73 handler.setsockname = function (_, ...) return sock:setsockname(...); end
74 handler.setpeername = function (_, ...) peername = (...); local ret = sock:setpeername(...); _:set_send(dummy_send); return ret; end
75 handler.connect = function (_, ...) return sock:connect(...) end
76 --handler.send = function (_, data) _:write(data); return _.sendbuffer and _.sendbuffer(); end
77 handler.send = function (_, data) return sock:send(data); end
81 dns.socket_wrapper_set(new_async_socket);