Add redundancy to PacketServer

lib/consts.dart

@@ -1,3 +1,3 @@
 class Constants {
-  static const VERSION = "1.2.082924+0707";
+  static const VERSION = "1.2.082924+0756";
 }

lib/packets/packets.dart

@@ -1,6 +1,9 @@
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
+import 'dart:typed_data';
+
+import 'package:libac_dart/utils/Hashing.dart';
 
 import '../nbt/NbtIo.dart';
 import '../nbt/Stream.dart';
@@ -20,26 +23,63 @@ class PacketServer {
       print(
           "New connection from ${sock.remoteAddress.address}:${sock.remotePort}");
 
+      ByteLayer layer = ByteLayer();
+
       try {
-        sock.listen((data) async {
+        sock.listen((data) {
+          layer.writeBytes(data);
+        }, onDone: () async {
+          layer.resetPosition();
           try {
-            CompoundTag tag = await NbtIo.readFromStream(data);
+            List<int> dataHash = layer.readBytes(256);
-            StringBuilder builder = StringBuilder();
+            int sequenceID = layer.readLong();
-            Tag.writeStringifiedNamedTag(tag, builder, 0);
+            print("Sequence ID in request: $sequenceID");
 
-            print("Request from client: \n${builder}");
+            int numBytes = layer.readLong();
 
-            C2SRequestPacket request = C2SRequestPacket();
+            List<int> remainingBytes = layer.readBytes(numBytes);
-            request.decodeTag(tag);
 
-            PacketResponse reply = await request.handleServerPacket();
+            String sha256OriginalHash = Hashing.bytes2Hash(dataHash);
+            String sha256Hash =
+                Hashing.bytes2Hash(Hashing.sha1Sum(remainingBytes));
+            if (sha256OriginalHash == sha256Hash) {
+              CompoundTag tag = await NbtIo.readFromStream(
+                  Uint8List.fromList(remainingBytes));
+              StringBuilder builder = StringBuilder();
+              Tag.writeStringifiedNamedTag(tag, builder, 0);
 
-            // Server uses NBT to communicate
+              print("Request from client: \n${builder}");
-            builder = StringBuilder();
-            Tag.writeStringifiedNamedTag(reply.replyDataTag, builder, 0);
 
-            print("Response to client: \n${builder}");
+              C2SRequestPacket request = C2SRequestPacket();
-            sock.add(await NbtIo.writeToStream(reply.replyDataTag));
+              request.decodeTag(tag);
+
+              PacketResponse reply = await request.handleServerPacket();
+
+              // Server uses NBT to communicate
+              builder = StringBuilder();
+              Tag.writeStringifiedNamedTag(reply.replyDataTag, builder, 0);
+
+              print("Response to client: \n${builder}");
+              Uint8List nbtData = await NbtIo.writeToStream(reply.replyDataTag);
+
+              layer.clear();
+              layer.writeLong(sequenceID);
+              layer.writeByte(0xFF); // Successful receipt
+              layer.writeBytes(Hashing.sha256Sum(nbtData));
+              layer.writeLong(nbtData.lengthInBytes);
+              layer.writeBytes(nbtData);
+
+              sock.add(layer.bytes);
+            } else {
+              // Return a failure packet
+              layer.clear();
+              layer.writeLong(sequenceID);
+              layer.writeByte(0x00);
+
+              sock.add(layer.bytes); // Failure code.
+              print(
+                  "ERROR: The inbound hash did not match real hash: $sha256OriginalHash != $sha256Hash\n> REFUSING TO PROCESS PACKET. SENDING ERROR CODE TO CLIENT");
+            }
           } catch (E, stack) {
             response.contents
                 .put("error", StringTag.valueOf("Malformed request packet"));
@@ -50,11 +90,11 @@ class PacketServer {
             await sock.flush();
             sock.close();
           }
-        }, onDone: () {
+          layer.clear();
-          sock.close();
         }, onError: (E) {
           print("ERROR: ${E}");
           sock.close();
+          layer.clear();
         });
       } catch (E) {
         sock.close();
@@ -68,6 +108,7 @@ class PacketClient {
   bool connected = false;
   String lastIP = "";
   int port = 25306;
+  int packetSequence = 0;
 
   PacketClient();
 
@@ -93,45 +134,81 @@ class PacketClient {
     C2SRequestPacket request = C2SRequestPacket();
     request.payload = packet;
     request.cap = packet.getChannelID();
+    bool success = false;
 
-    socket!.add(await NbtIo.writeToStream(request.encodeTag().asCompoundTag()));
+    ByteLayer layer = ByteLayer();
-    CompoundTag ct = CompoundTag();
-    Completer<void> onCompletion = Completer();
-    socket!.listen((data) async {
-      try {
-        CompoundTag result = await NbtIo.readFromStream(data);
 
-        StringBuilder builder = StringBuilder();
+    Uint8List nbtData =
-        Tag.writeStringifiedNamedTag(result, builder, 0);
+        await NbtIo.writeToStream(request.encodeTag().asCompoundTag());
+    List<int> nbtDataHash = Hashing.sha256Sum(nbtData);
 
-        print("Response from server: \n${builder}");
+    ByteLayer reply = ByteLayer();
-        ct.put("result", result);
+    CompoundTag NBTTag = CompoundTag();
-      } catch (E, S) {
-        print(S);
-      } finally {
-        onCompletion.complete();
-      }
-    }, onError: (E, stack) {
-      print("ERROR: ${E}\n${stack}");
-      if (!onCompletion.isCompleted) onCompletion.complete();
-    }, onDone: () {
-      print("Request completed");
-    });
 
-    await onCompletion.future;
+    while (!success) {
-    await close();
+      layer.clear();
+      layer.writeBytes(nbtDataHash);
+      layer.writeLong(packetSequence);
+      layer.writeLong(nbtData.lengthInBytes);
+      layer.writeBytes(nbtData);
 
-    await startConnect(lastIP, port);
+      Completer responseWait = Completer();
-    S2CResponse reply = S2CResponse();
+
-    try {
+      socket!.add(layer.bytes);
-      reply.decodeTag(ct.get("result")!.asCompoundTag());
+
-    } catch (E, stack) {
+      socket!.listen((data) {
-      reply.contents = CompoundTag(); // This is essentially a null response
+        reply.writeBytes(data);
-      reply.contents.put("error", StringTag.valueOf(E.toString()));
+      }, onDone: () async {
-      reply.contents.put("stacktrace", StringTag.valueOf(stack.toString()));
+        // Validate response validity
+        reply.resetPosition();
+        int sequence = reply.readLong();
+        int successReceipt = reply.readByte();
+        List<int> serverHash = reply.readBytes(256);
+        String srvHashStr = Hashing.bytes2Hash(serverHash);
+        int numBytes = reply.readLong();
+        List<int> pktBytes = reply.readBytes(numBytes);
+        String pktHash = Hashing.bytes2Hash(Hashing.sha256Sum(pktBytes));
+
+        if (successReceipt == 0xFF &&
+            packetSequence == sequence &&
+            srvHashStr == pktHash) success = true;
+
+        if (success) {
+          NBTTag = await NbtIo.readFromStream(Uint8List.fromList(pktBytes));
+        }
+
+        responseWait.complete();
+      }, onError: () {
+        if (!responseWait.isCompleted) responseWait.complete();
+      });
+
+      await responseWait.future;
+
+      packetSequence++;
+      if (!success) await Future.delayed(Duration(seconds: 5));
     }
 
-    return reply;
+    CompoundTag ct = CompoundTag();
+    StringBuilder builder = StringBuilder();
+    Tag.writeStringifiedNamedTag(NBTTag, builder, 0);
+
+    print("Response from server: \n${builder}");
+    ct.put("result", NBTTag);
+
+    await close();
+
+    if (shouldReconnect) await startConnect(lastIP, port);
+
+    S2CResponse replyPkt = S2CResponse();
+    try {
+      replyPkt.decodeTag(ct.get("result")!.asCompoundTag());
+    } catch (E, stack) {
+      replyPkt.contents = CompoundTag(); // This is essentially a null response
+      replyPkt.contents.put("error", StringTag.valueOf(E.toString()));
+      replyPkt.contents.put("stacktrace", StringTag.valueOf(stack.toString()));
+    }
+
+    return replyPkt;
   }
 
   Future<void> close() async {

lib/utils/Hashing.dart

@@ -5,17 +5,17 @@ import 'package:crypto/crypto.dart';
 class Hashing {
   /// This will generate the md5 bytes and hash it using #bytes2Hash
   static String md5Hash(String input) {
-    return bytes2Hash(md5Sum(input));
+    return bytes2Hash(md5SumStr(input));
   }
 
   /// This will generate the Sha1 bytes and hash it using #bytes2Hash
   static String sha1Hash(String input) {
-    return bytes2Hash(sha1Sum(input));
+    return bytes2Hash(sha1SumStr(input));
   }
 
   /// This will generate the Sha256 bytes and hash it using #bytes2Hash.
   static String sha256Hash(String input) {
-    return bytes2Hash(sha256Sum(input));
+    return bytes2Hash(sha256SumStr(input));
   }
 
   /// This function takes a list of bytes and returns a hash string
@@ -29,17 +29,32 @@ class Hashing {
   }
 
   /// This function returns the bytes instead of a hash string
-  static List<int> md5Sum(String input) {
+  static List<int> md5SumStr(String input) {
     return md5.convert(utf8.encode(input)).bytes;
   }
 
   /// This functions returns the bytes instead of a hash string
-  static List<int> sha1Sum(String input) {
+  static List<int> sha1SumStr(String input) {
     return sha1.convert(utf8.encode(input)).bytes;
   }
 
   /// This function returns the bytes instead of a hash string
-  static List<int> sha256Sum(String input) {
+  static List<int> sha256SumStr(String input) {
     return sha256.convert(utf8.encode(input)).bytes;
   }
+
+  /// This function returns the bytes instead of a hash string
+  static List<int> md5Sum(List<int> input) {
+    return md5.convert(input).bytes;
+  }
+
+  /// This functions returns the bytes instead of a hash string
+  static List<int> sha1Sum(List<int> input) {
+    return sha1.convert(input).bytes;
+  }
+
+  /// This function returns the bytes instead of a hash string
+  static List<int> sha256Sum(List<int> input) {
+    return sha256.convert(input).bytes;
+  }
 }

pubspec.yaml

@@ -1,6 +1,6 @@
 name: libac_dart
 description: "Aria's Creations code library"
-version: 1.2.082924+0707
+version: 1.2.082924+0756
 homepage: "https://zontreck.com"