net.adns: Add helper module for performing non-blocking DNS lookups

1 files changed, 38 insertions, 0 deletions

diff --git a/net/adns.lua b/net/adns.lua
new file mode 100644
index 00000000..fe35d2dd
--- /dev/null
+++ b/net/adns.lua
@@ -0,0 +1,38 @@
+local server = require "net.server";
+local dns = require "net.dns2";
+
+local log = require "util.logger".init("adns");
+
+local coroutine, tostring = coroutine, tostring;
+
+module "adns"
+
+function lookup(handler, qname, qtype, qclass)
+	return dns.peek(qname, qtype, qclass) or
+		coroutine.wrap(function ()
+				log("debug", "Records for "..qname.." not in cache, sending query (%s)...", tostring(coroutine.running()));
+				dns.query(qname, qtype, qclass);
+				coroutine.yield(nil); -- Wait for reply
+				log("debug", "Reply for "..qname.." (%s)", tostring(coroutine.running()));
+				handler(dns.peek(qname, qtype, qclass));
+			end)();
+end
+
+function new_async_socket(sock)
+	local newconn = {};
+	local listener = {};
+	function listener.incoming(conn, data)
+		dns.feed(sock, data);
+	end
+	function listener.disconnect()
+	end
+	newconn.handler, newconn._socket = server.wrapclient(sock, "dns", 53, listener);
+	newconn.handler.settimeout = function () end
+	newconn.handler.setsockname = function (_, ...) return sock:setsockname(...); end
+	newconn.handler.setpeername = function (_, ...) return sock:setpeername(...); end
+	newconn.handler.connect = function (_, ...) return sock:connect(...) end	
+	newconn.handler.send = function (_, data) return _.write(data) end	
+	return newconn.handler;
+end
+
+dns:socket_wrapper_set(new_async_socket);