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94 lines
3.0 KiB
94 lines
3.0 KiB
-- Prosody IM
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-- Copyright (C) 2008-2010 Matthew Wild
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-- Copyright (C) 2008-2010 Waqas Hussain
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--
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-- This project is MIT/X11 licensed. Please see the
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-- COPYING file in the source package for more information.
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--
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local server = require "net.server";
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local dns = require "net.dns";
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local log = require "util.logger".init("adns");
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local coroutine, tostring, pcall = coroutine, tostring, pcall;
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local function dummy_send(sock, data, i, j) return (j-i)+1; end
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local _ENV = nil;
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local function lookup(handler, qname, qtype, qclass)
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return coroutine.wrap(function (peek)
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if peek then
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log("debug", "Records for %s already cached, using those...", qname);
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handler(peek);
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return;
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end
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log("debug", "Records for %s not in cache, sending query (%s)...", qname, tostring(coroutine.running()));
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local ok, err = dns.query(qname, qtype, qclass);
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if ok then
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coroutine.yield({ qclass or "IN", qtype or "A", qname, coroutine.running()}); -- Wait for reply
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log("debug", "Reply for %s (%s)", qname, tostring(coroutine.running()));
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end
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if ok then
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ok, err = pcall(handler, dns.peek(qname, qtype, qclass));
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else
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log("error", "Error sending DNS query: %s", err);
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ok, err = pcall(handler, nil, err);
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end
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if not ok then
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log("error", "Error in DNS response handler: %s", tostring(err));
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end
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end)(dns.peek(qname, qtype, qclass));
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end
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local function cancel(handle, call_handler, reason)
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log("warn", "Cancelling DNS lookup for %s", tostring(handle[3]));
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dns.cancel(handle[1], handle[2], handle[3], handle[4], call_handler);
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end
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local function new_async_socket(sock, resolver)
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local peername = "<unknown>";
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local listener = {};
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local handler = {};
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local err;
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function listener.onincoming(conn, data)
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if data then
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dns.feed(handler, data);
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end
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end
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function listener.ondisconnect(conn, err)
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if err then
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log("warn", "DNS socket for %s disconnected: %s", peername, err);
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local servers = resolver.server;
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if resolver.socketset[conn] == resolver.best_server and resolver.best_server == #servers then
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log("error", "Exhausted all %d configured DNS servers, next lookup will try %s again", #servers, servers[1]);
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end
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resolver:servfail(conn); -- Let the magic commence
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end
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end
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handler, err = server.wrapclient(sock, "dns", 53, listener);
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if not handler then
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return nil, err;
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end
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handler.settimeout = function () end
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handler.setsockname = function (_, ...) return sock:setsockname(...); end
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handler.setpeername = function (_, ...) peername = (...); local ret, err = sock:setpeername(...); _:set_send(dummy_send); return ret, err; end
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handler.connect = function (_, ...) return sock:connect(...) end
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--handler.send = function (_, data) _:write(data); return _.sendbuffer and _.sendbuffer(); end
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handler.send = function (_, data)
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log("debug", "Sending DNS query to %s", peername);
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return sock:send(data);
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end
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return handler;
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end
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dns.socket_wrapper_set(new_async_socket);
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return {
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lookup = lookup;
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cancel = cancel;
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new_async_socket = new_async_socket;
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};
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