From 26816ee0b14becfa2882a84f2b25635a61558498 Mon Sep 17 00:00:00 2001
From: AJ ONeal <aj@daplie.com>
Date: Fri, 17 Feb 2017 19:40:01 -0700
Subject: [PATCH] send query, receive response

---
 bin/dig.js | 161 +++++++++++++++++++++++++++++++++++------------------
 1 file changed, 106 insertions(+), 55 deletions(-)

diff --git a/bin/dig.js b/bin/dig.js
index b3399d0..1633611 100755
--- a/bin/dig.js
+++ b/bin/dig.js
@@ -52,6 +52,108 @@ function hexdump(ab) {
   return head + '\n' + str + '\n' + trail;
 }
 
+function request(query, opts) {
+  var queryAb = dnsjs.DNSPacket.write(query);
+
+  if (opts.debug) {
+    console.log('');
+    console.log('DNS Question:');
+    console.log('');
+    console.log(query);
+    console.log('');
+    console.log(hexdump(queryAb));
+    console.log('');
+    console.log(dnsjs.DNSPacket.parse(queryAb));
+    console.log('');
+  }
+
+  var count = 0;
+  var handlers = {};
+  var server = dgram.createSocket({
+    type: 'udp4'
+  , reuseAddr: true
+  });
+
+  handlers.onError = function (err) {
+      console.error("error:", err.stack);
+      server.close();
+  };
+  handlers.onMessage = function (nb) {
+    var packet = dnsjs.DNSPacket.parse(nb.buffer.slice(nb.byteOffset, nb.byteOffset + nb.byteLength));
+
+    if (packet.id !== query.id) {
+      console.log('ignoring packet for ', packet.question[0].name);
+    }
+
+    if (!opts.mdns) {
+      server.close();
+    }
+
+    console.log('');
+    console.log('DNS Response:');
+    console.log(packet);
+
+    if (opts.output) {
+      var path = require('path');
+      var filename = packet.question[0].typeName + '-' + count + '.bin';
+      var fullpath = path.join('samples', filename);
+
+      count += 1;
+
+      return fs.writeFileAsync(fullpath, nb).then(function () {
+        console.log('wrote ' + nb.length + ' bytes to ' + fullpath);
+      });
+    }
+  };
+  handlers.onListening = function () {
+    /*jshint validthis:true*/
+    var server = this;
+    var nameserver = opts.nameserver;
+    var nameservers;
+    var index;
+
+    if (!nameserver) {
+      nameservers = require('dns').getServers();
+      index = (Math.round(Math.random() * 7777)) % nameservers.length;
+      nameserver = nameservers[index];
+      if (opts.debug) {
+        console.log(index, nameservers);
+      }
+    }
+
+    if (opts.mdns || '224.0.0.251' === opts.nameserver) {
+      server.setBroadcast(true);
+      server.addMembership(opts.nameserver);
+    }
+
+    if (opts.debug) {
+      console.log('');
+      console.log('Bound and Listening:');
+      console.log(server.address());
+    }
+
+    if (opts.debug) {
+      console.log('querying ' + nameserver + ':' + opts.port);
+    }
+    server.send(Buffer.from(queryAb), opts.port, nameserver, function () {
+      if (opts.debug) {
+        console.log('');
+        console.log('request sent');
+      }
+    });
+  };
+
+
+  server.on('error', handlers.onError);
+  server.on('message', handlers.onMessage);
+  server.on('listening', handlers.onListening);
+
+  // 0 dns request
+  // 53 dns server
+  // 5353 mdns
+  server.bind(0);
+}
+
 cli.main(function (args, cli) {
   args.forEach(function (arg) {
     if (-1 !== commonTypes.indexOf(arg.toUpperCase())) {
@@ -88,6 +190,9 @@ cli.main(function (args, cli) {
     if (!cli.port) {
       cli.port = cli.p = 5353;
     }
+    if (!cli.nameserver) {
+      cli.nameserver = '224.0.0.251';
+    }
   }
 
   if (!cli.type) {
@@ -128,60 +233,6 @@ cli.main(function (args, cli) {
       }
     ]
   };
-  var queryAb = dnsjs.DNSPacket.write(query);
 
-  if (cli.debug) {
-    console.log('');
-    console.log('DNS Question:');
-    console.log('');
-    console.log(query);
-    console.log('');
-    console.log(hexdump(queryAb));
-    console.log('');
-    console.log(dnsjs.DNSPacket.parse(queryAb));
-    console.log('');
-  }
-
-
-
-
-    process.exit(1);
-  var server = dgram.createSocket({
-    type: 'udp4'
-  , reuseAddr: true
-  });
-
-  var handlers = {};
-  handlers.onError = function (err) {
-      console.error("error:", err.stack);
-      server.close();
-  };
-  handlers.onMessage = function (buffer) {
-    var path = require('path');
-    var filename = type + '-' + count + '.mdns.bin';
-    var fullpath = path.join('samples', filename);
-
-    count += 1;
-
-    fs.writeFileAsync(fullpath, buffer).then(function () {
-      console.log('wrote ' + buffer.length + ' bytes to ' + fullpath);
-    });
-  };
-  handlers.onListening = function () {
-    /*jshint validthis:true*/
-    var server = this;
-    console.log(server.address());
-
-    server.setBroadcast(true);
-    server.addMembership('224.0.0.251');
-  };
-
-
-  server.on('error', handlers.onError);
-  server.on('message', handlers.onMessage);
-  server.on('listening', handlers.onListening);
-
-  // 53 dns
-  // 5353 mdns
-  server.bind(5353);
+  request(query, cli);
 });