From f63674382528e0de98a68d9f9427eba6feea3629 Mon Sep 17 00:00:00 2001
From: git <git@fredericofalcao.com>
Date: Sun, 15 Jun 2025 14:28:51 +0100
Subject: [PATCH] Update main.js

---
 main.js | 127 +++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 94 insertions(+), 33 deletions(-)

diff --git a/main.js b/main.js
index b153879..b3cdb06 100644
--- a/main.js
+++ b/main.js
@@ -76,22 +76,18 @@ function sniffmDNSLocalPackets() {
 	  }
 	})
 
-	// 2. Listen for queries
-	mdns.on('query', function(query) {/* console.log("query requested",query);*/});
-
-	// 3. Handle the server being destroyed
+	
+	// 2. Handle the server being destroyed
 	mdns.on('destroyed', function () {console.log('Server destroyed.');process.exit(0);});
 
-	// 4. Handle the onReady event
+	// 3. Handle the onReady event
 	mdns.on('ready', function () {
 		
 	  console.log("mDNS server is ready...");
 	  // mdns.query({questions:[{ name: '_:googlecast._tcp.local', type: 'PTR', class: 'IN'}]} );
 	})
 
-	// initialize the server now that we are watching for events
-	mdns.initServer()
-
+	
 }
 function injectmDNSPacketLocally(type,name,data,flush = true,_class = 'IN',ttl = 120) { 
 	console.log(`sending packet ${name} of ${type} with data: ${data}`);
@@ -106,6 +102,84 @@ function injectmDNSPacketLocally(type,name,data,flush = true,_class = 'IN',ttl =
 		}
 ]});}
 
+function replyLocallyWithRemoteDevicesData(name,type,query) {
+    const answers = [];
+	if (!db.remote) db.remote = {};
+    if (!db.remote.PTR) db.remote.PTR = {};
+    if (!db.remote.A) db.remote.A = {};
+
+    // 1. If the query is asking for a PTR (pointer to a service)
+    if (type === 'PTR' && db.remote.PTR && db.remote.PTR[name]) {
+      for (let ptrData of db.remote.PTR[name]) {
+        answers.push({
+          name,              // The service name being queried
+          type: 'PTR',       // Type of DNS record
+          class: 'IN',       // Internet class
+          ttl: 120,          // Time-to-live (how long to cache)
+          data: ptrData      // The actual pointer data (e.g. device instance name)
+        });
+      }
+    }
+
+    // 2. If the query is for an A record (IPv4 address of a device)
+    if (type === 'A' && db.remote.A && db.remote.A[name]) {
+      answers.push({
+        name,
+        type: 'A',
+        class: 'IN',
+        ttl: 120,
+        data: db.remote.A[name]  // The IPv4 address
+      });
+    }
+
+    // 3. If the query is for an SRV record (hostname + port of a service)
+    if (type === 'SRV' && db.remote[name] && db.remote[name].SRV !== null) {
+      answers.push({
+        name,
+        type: 'SRV',
+        class: 'IN',
+        ttl: 120,
+        data: db.remote[name].SRV  // Must be an object like { port, target, priority, weight }
+      });
+    }
+
+    // 4. If the query is for a TXT record (extra metadata)
+    if (type === 'TXT' && db.remote[name] && db.remote[name].TXT !== null) {
+      answers.push({
+        name,
+        type: 'TXT',
+        class: 'IN',
+        ttl: 120,
+        // Convert plain string to buffer; required by mdns-server
+        data: Buffer.from(db.remote[name].TXT, 'utf8')
+      });
+    }
+    // 5. Many mDNS tools (like Avahi or Bonjour) send type: 'ANY' queries to discover all records for a name.
+    if (type === 'ANY') {
+      // Respond with everything you know about this name
+      if (db.remote.PTR && db.remote.PTR[name]) {
+        for (let ptrData of db.remote.PTR[name]) {
+          answers.push({ name, type: 'PTR', class: 'IN', ttl: 120, data: ptrData });
+        }
+      }
+      if (db.remote.A && db.remote.A[name]) {
+        answers.push({ name, type: 'A', class: 'IN', ttl: 120, data: db.remote.A[name] });
+      }
+      if (db.remote[name]) {
+        const r = db.remote[name];
+        if (r.SRV) answers.push({ name, type: 'SRV', class: 'IN', ttl: 120, data: r.SRV });
+        if (r.TXT) answers.push({ name, type: 'TXT', class: 'IN', ttl: 120, data: Buffer.from(r.TXT, 'utf8') });
+      }
+    }	
+
+    // 6. If we prepared any answers, respond to the query
+    if (answers.length > 0) {
+      console.log(`Responding with ${answers.length} answer(s) for ${name}`);
+      mdns.respond({ answers });
+    }
+	
+}
+
 
 
 /*********************************
@@ -121,30 +195,17 @@ const LOCAL_IP_ADDR = getLocalNetworkAddressesIPs()[0];
 const mdns = require('mdns-server')({interface: LOCAL_IP_ADDR,reuseAddr: true,loopback: false,noInit: true});
 sniffmDNSLocalPackets();
 
-setInterval(function(){
-    if (!db.remote || !db.remote.PTR) return;
 
-	// INJECT PTR - Pointers services
-	for (let name in db.remote.PTR) {
-		for (let i in db.remote.PTR[name])
-			injectmDNSPacketLocally('PTR',name,db.remote.PTR[name][i]);
-	}
-	// INJECT A - Addresses
-	for (name in db.remote.A) {
-		injectmDNSPacketLocally('A',name,db.remote.A[name]);
-	}
-	
-	
-	// INJECT SRV,TXT
-	for (name in db.remote) {
-		if (["PTR","A"].includes(name)) continue;
-		if (db.remote[name].SRV !== null) 
-			injectmDNSPacketLocally('SRV',name,db.remote[name].SRV);
-		if (db.remote[name].TXT !== null) 
-			injectmDNSPacketLocally('TXT',name,Buffer.from(db.remote[name].TXT, 'utf8'));
+mdns.on('query', function (query) {
+  // Loop through each question in the mDNS query
+  query.questions.forEach(q => {
+    const { name, type } = q;
+    console.log(`Received mDNS query for ${name} (${type})`);
+    replyLocallyWithRemoteDevicesData(name,type,q);
+    
+    
+  });
+});
 
-	}
-	
-	
-	
-},5000);
\ No newline at end of file
+// initialize the server now that we are watching for events
+mdns.initServer()