coolaj86
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digd.js
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Code Issues 7 Pull Requests 2 Releases Activity

add tcp support

This commit is contained in:
AJ ONeal 2017-12-14 20:26:28 -07:00
parent bd8b57efd1
commit c3934acb30
4 changed files with 175 additions and 58 deletions
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2
README.md
View File

@ -89,6 +89,8 @@ Options
+time=<seconds> Sets the timeout for a query in seconds.
+norecurse Set `ra` flag to 0. Do not perform recursion.
+aaonly Set `aa` flag to 1. Do not respond with non-authoritative responses.
+notcp Disable TCP server (default in v1.2)
+tcp Enable TCP server (default in v1.3)
--debug verbose output
```

103
bin/digd.js
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@ -5,9 +5,7 @@
var cli = require('cli');
var pkg = require('../package.json');
var dig = require('dig.js/dns-request');
var dgram = require('dgram');
var dnsjs = require('dns-suite');
var crypto = require('crypto');
var common = require('dig.js/common');
var defaultNameservers = require('dns').getServers();
var hexdump;
@ -49,8 +47,32 @@ cli.main(function (args, cli) {
cli.norecurse = true;
return;
}
if (arg === '+notcp') {
if (cli.notcp) {
console.error("'+notcp' was specified more than once");
process.exit(1);
return;
}
cli.notcp = true;
return;
}
if (arg === '+tcp') {
if (cli.tcp) {
console.error("'+tcp' was specified more than once");
process.exit(1);
return;
}
cli.tcp = true;
return;
}
});
if (!cli.tcp) {
if (!cli.notcp) {
console.info("[WARNING] Set '+notcp' to disable tcp connections. The default behavior changes to +tcp in v1.3");
}
}
if (cli.mdns) {
if (!cli.type) {
cli.type = cli.t = 'PTR';
@ -73,32 +95,10 @@ cli.main(function (args, cli) {
}
}
var handlers = {};
var server = dgram.createSocket({
type: cli.udp6 ? 'udp6' : 'udp4'
, reuseAddr: true
});
server.bind({
port: cli.port
, address: cli.address
});
handlers.onError = function (err) {
if ('EACCES' === err.code) {
console.error("");
console.error("EACCES: Couldn't bind to port. You probably need to use sudo, authbind, or setcap.");
console.error("");
process.exit(123);
return;
}
console.error("error:", err.stack);
server.close();
};
handlers.onMessage = function (nb, rinfo) {
console.log('[DEBUG] got a message');
var queryAb = nb.buffer.slice(nb.byteOffset, nb.byteOffset + nb.byteLength);
var dnsd = {};
dnsd.onMessage = function (nb, cb) {
var byteOffset = nb._dnsByteOffset || nb.byteOffset;
var queryAb = nb.buffer.slice(byteOffset, byteOffset + nb.byteLength);
var query;
var count;
@ -215,12 +215,11 @@ cli.main(function (args, cli) {
console.error("Could not write empty DNS response");
console.error(e);
console.error(emptyResp);
cb(e, null, '[DEV] response sent (empty)');
return;
}
server.send(newAb, rinfo.port, rinfo.address, function () {
console.log('[DEV] response sent (empty)', rinfo.port, rinfo.address);
});
cb(null, newAb, '[DEV] response sent (empty)');
}
function sendResponse(newPacket) {
@ -232,12 +231,11 @@ cli.main(function (args, cli) {
console.error("Could not write DNS response from local");
console.error(e);
console.error(newPacket);
cb(e, null, '[DEV] response sent (local query)');
return;
}
server.send(newAb, rinfo.port, rinfo.address, function () {
console.log('[DEV] response sent (local query)', rinfo.port, rinfo.address);
});
cb(null, newAb, '[DEV] response sent (local query)');
}
function recurse() {
@ -290,12 +288,11 @@ cli.main(function (args, cli) {
} catch(e) {
console.error("Could not write DNS response");
console.error(newResponse);
cb(e, null, '[DEV] response sent');
return;
}
server.send(newAb, rinfo.port, rinfo.address, function () {
console.log('[DEV] response sent', rinfo.port, rinfo.address);
});
cb(null, newAb, '[DEV] response sent');
}
}
@ -335,7 +332,8 @@ cli.main(function (args, cli) {
console.log('request sent to', res.nameserver);
}
*/
console.log('[DEV] query sent (recurse)', rinfo.port, rinfo.address);
//console.log('[DEV] query sent (recurse)', rinfo.port, rinfo.address);
//dnsd.onSent('[DEV] query sent (recurse)');
}
, onTimeout: function (res) {
console.log(";; [" + q.name + "] connection timed out; no servers could be reached");
@ -393,32 +391,24 @@ cli.main(function (args, cli) {
return;
}
require('../lib/digd.js').query(engine, query, respondWithResults);
};
handlers.onListening = function () {
/*jshint validthis:true*/
var server = this;
cli.defaultNameservers = defaultNameservers;
require('../lib/udpd.js').create(cli, dnsd).on('listening', function () {
cli.chosenNameserver = cli.nameserver;
var index;
if (!cli.chosenNameserver) {
index = crypto.randomBytes(2).readUInt16BE(0) % defaultNameservers.length;
cli.chosenNameserver = defaultNameservers[index];
index = require('crypto').randomBytes(2).readUInt16BE(0) % cli.defaultNameservers.length;
cli.chosenNameserver = cli.defaultNameservers[index];
if (cli.debug) {
console.log('index, defaultNameservers', index, defaultNameservers);
console.log('index, defaultNameservers', index, cli.defaultNameservers);
}
}
if (cli.mdns || '224.0.0.251' === cli.nameserver) {
server.setBroadcast(true);
server.addMembership(cli.nameserver);
}
console.log('');
console.log('Bound and Listening:');
console.log(server.address().address + '#' + server.address().port + ' (' + server.type + ')');
};
});
if (cli.tcp /* TODO v1.3 !cli.notcp */) {
require('../lib/tcpd.js').create(cli, dnsd);
}
console.log('');
if (!cli.nocmd) {
@ -426,7 +416,4 @@ cli.main(function (args, cli) {
console.log(';; global options: +cmd');
}
server.on('error', handlers.onError);
server.on('message', handlers.onMessage);
server.on('listening', handlers.onListening);
});

70
lib/tcpd.js Normal file
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@ -0,0 +1,70 @@
'use strict';
module.exports.create = function (cli, dnsd) {
function runTcp() {
var tcpServer = require('net').createServer({ }, function (c) {
c.on('error', function (err) {
console.warn("TCP Connection Error:");
console.warn(err);
});
c.on('data', function (nb) {
//console.log('TCP data.length:', nb.length);
//console.log(nb.toString('hex'));
// DNS packets include a 2-byte length header
var count = nb.length;
var length = nb[0] << 8;
length = length | nb[1];
count -= 2;
// TODO slice?
nb._dnsByteOffset = nb.byteOffset + 2;
if (length !== count) {
console.error("Handling TCP packets > 512 bytes not implemented.");
c.end();
return;
}
// TODO pad two bytes for lengths
dnsd.onMessage(nb, function (err, newAb, dbgmsg) {
var lenbuf = Buffer.from([ newAb.length >> 8, newAb.length & 255 ]);
// TODO XXX generate legit error packet
if (err) { console.error("Error", err); c.end(); return; }
console.log('TCP ' + dbgmsg);
c.write(lenbuf);
c.end(newAb);
});
});
c.on('end', function () {
console.log('TCP client disconnected from server');
});
});
tcpServer.on('error', function (err) {
if ('EADDRINUSE' === err.code) {
console.error("Port '" + cli.port + "' is already in use.");
tcpServer.close();
process.exit(0);
}
if ('EACCES' === err.code) {
console.error("Could not bind on port '" + cli.port + "': EACCESS (you probably need root permissions)");
tcpServer.close();
process.exit(0);
}
console.error("TCP Server Error:");
console.error(err);
tcpServer.close(function () {
setTimeout(runTcp, 1000);
});
});
tcpServer.listen(cli.port, function () {
console.log('TCP Server bound');
});
return tcpServer;
}
return runTcp();
};

58
lib/udpd.js Normal file
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@ -0,0 +1,58 @@
'use strict';
module.exports.create = function (cli, dnsd) {
var server = require('dgram').createSocket({
type: cli.udp6 ? 'udp6' : 'udp4'
, reuseAddr: true
});
server.bind({
port: cli.port
, address: cli.address
});
var handlers = {};
handlers.onError = function (err) {
if ('EACCES' === err.code) {
console.error("");
console.error("EACCES: Couldn't bind to port. You probably need to use sudo, authbind, or setcap.");
console.error("");
process.exit(123);
return;
}
console.error("error:", err.stack);
server.close();
};
handlers.onMessage = function (nb, rinfo) {
//console.log('[DEBUG] got a UDP message', nb.length);
//console.log(nb.toString('hex'));
dnsd.onMessage(nb, function (err, newAb, dbgmsg) {
// TODO send legit error message
if (err) { server.send(Buffer.from([0x00])); return; }
server.send(newAb, rinfo.port, rinfo.address, function () {
console.log(dbgmsg, rinfo.port, rinfo.address);
});
});
};
handlers.onListening = function () {
/*jshint validthis:true*/
var server = this;
if (cli.mdns || '224.0.0.251' === cli.nameserver) {
server.setBroadcast(true);
server.addMembership(cli.nameserver);
}
console.log('');
console.log('Bound and Listening:');
console.log(server.address().address + '#' + server.address().port + ' (' + server.type + ')');
};
server.on('error', handlers.onError);
server.on('message', handlers.onMessage);
server.on('listening', handlers.onListening);
return server;
};