MQTT 3.1.1 Packet Decoding and Encoding

Directory.Packages.props

@@ -2,12 +2,11 @@
   <PropertyGroup>
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
   </PropertyGroup>
-
   <!-- Akka.NET Package Versions -->
   <ItemGroup>
     <PackageVersion Include="Akka.Hosting" Version="1.5.18" />
+    <PackageVersion Include="CommunityToolkit.HighPerformance" Version="8.2.2" />
   </ItemGroup>
-
   <!-- Test Package Versions -->
   <ItemGroup>
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
@@ -18,4 +17,4 @@
     <PackageVersion Include="Verify.Xunit" Version="17.10.2" />
     <PackageVersion Include="Verify.DiffPlex" Version="1.3.0" />
   </ItemGroup>
-</Project>
+</Project>

TurboMqtt.sln.DotSettings

@@ -3,4 +3,5 @@
 <copyright file="${File.FileName}" company="Petabridge, LLC">
      Copyright (C) ${File.CreatedYear} - ${CurrentDate.Year} Petabridge, LLC <https://petabridge.com>
 </copyright>
------------------------------------------------------------------------</s:String></wpf:ResourceDictionary>
+-----------------------------------------------------------------------</s:String>
+	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EFeature_002EServices_002ECodeCleanup_002EFileHeader_002EFileHeaderSettingsMigrate/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>

src/TurboMqtt.Core/ControlPacketHeaders.cs

@@ -3,7 +3,6 @@
 //      Copyright (C) 2024 - 2024 Petabridge, LLC <https://petabridge.com>
 // </copyright>
 // -----------------------------------------------------------------------
-
 namespace TurboMqtt.Core;
 
 /// <summary>
@@ -14,21 +13,21 @@ namespace TurboMqtt.Core;
 ///
 /// Also supports MQTT 5.0.
 /// </remarks>
-public enum MqttPacketType : byte
+public enum MqttPacketType
 {
-    Connect = 0x10,
-    ConnAck = 0x20,
-    Publish = 0x30,
-    PubAck = 0x40,
-    PubRec = 0x50,
-    PubRel = 0x60,
-    PubComp = 0x70,
-    Subscribe = 0x80,
-    SubAck = 0x90,
-    Unsubscribe = 0xA0,
-    UnsubAck = 0xB0,
-    PingReq = 0xC0,
-    PingResp = 0xD0,
-    Disconnect = 0xE0,
-    Auth = 0xF0
+    Connect = 1,
+    ConnAck =2,
+    Publish = 3,
+    PubAck = 4,
+    PubRec = 5,
+    PubRel = 6,
+    PubComp = 7,
+    Subscribe = 8,
+    SubAck = 9,
+    Unsubscribe = 10,
+    UnsubAck = 11,
+    PingReq = 12,
+    PingResp = 13,
+    Disconnect = 14,
+    Auth = 15
 }

src/TurboMqtt.Core/NonZeroUInt32.cs

@@ -11,11 +11,17 @@ namespace TurboMqtt.Core;
 /// </summary>
 public readonly struct NonZeroUInt32
 {
+    public static readonly NonZeroUInt32 MinValue = new(1);
+
     /// <summary>
     /// The value of the identifier.
     /// </summary>
     public uint Value { get; }
 
+    public NonZeroUInt32() : this(1)
+    {
+    }
+
     public NonZeroUInt32(uint value)
     {
         if (value == 0)

src/TurboMqtt.Core/PacketTypes/ConnectPacket.cs

@@ -11,18 +11,53 @@ namespace TurboMqtt.Core.PacketTypes;
 /// <summary>
 /// Used to initiate a connection to the MQTT broker.
 /// </summary>
-public class ConnectPacket(string clientId, MqttProtocolVersion protocolVersion) : MqttPacket
+public sealed class ConnectPacket(MqttProtocolVersion protocolVersion) : MqttPacket
 {
+    public const string DefaultClientId = "turbomqtt";
+
     public override MqttPacketType PacketType => MqttPacketType.Connect;
 
-    public string ClientId { get; } = clientId;
-    public ushort KeepAlive { get; set; }
+    public string ClientId { get; set; } = DefaultClientId;
+    public ushort KeepAliveSeconds { get; set; }
     public ConnectFlags Flags { get; set; }
-
-    public MqttLastWill? Will { get; set; }
-
-    public string? Username { get; set; }
-    public ReadOnlyMemory<byte>? Password { get; set; }
+
+    public MqttLastWill? Will
+    {
+        get;
+        set;
+    }
+
+    private string? _username;
+    public string? Username
+    {
+        get => _username;
+        set
+        {
+            _username = value;
+
+            // ensure that the username flag is set or unset
+            var flags = Flags;
+            flags.UsernameFlag = !string.IsNullOrEmpty(value);
+            Flags = flags;
+        }
+    }
+
+    private string? _password;
+
+    public string? Password
+    {
+        get => _password;
+        set
+        {
+            _password = value;
+            // ensure that the password flag is set or unset
+            var flags = Flags;
+            flags.PasswordFlag = !string.IsNullOrEmpty(value);
+            Flags = flags;
+        }
+    }
+
+    public string ProtocolName { get; set; } = "MQTT";
 
     public MqttProtocolVersion ProtocolVersion { get; } = protocolVersion;
 
@@ -37,7 +72,11 @@ public class ConnectPacket(string clientId, MqttProtocolVersion protocolVersion)
     public ReadOnlyMemory<byte>? AuthenticationData { get; set; } // MQTT 5.0 only
     public IReadOnlyDictionary<string, string>? UserProperties { get; set; } // MQTT 5.0 custom properties
 
-
+    public override string ToString()
+    {
+        return $"ConnectPacket(ClientId={ClientId}, KeepAliveSeconds={KeepAliveSeconds}, Flags={Flags}, Will={Will}, Username={Username}, Password={Password})";
+
+    }
 }
 
 /// <summary>
@@ -79,38 +118,42 @@ public struct ConnectFlags
     public bool WillFlag { get; set; }
     public bool CleanSession { get; set; }  // Renamed from CleanStart for 3.1.1 compatibility
 
-    public byte Encode(MqttProtocolVersion version)
+    public byte Encode()
     {
-        byte result = 0;
+        int result = 0;
         if (UsernameFlag)
-            result |= 0b1000_0000;
+            result |= 0x80;
         if (PasswordFlag)
-            result |= 0b0100_0000;
-        if (version == MqttProtocolVersion.V5_0 && WillRetain)
-            result |= 0b0010_0000;
+            result |= 0x40;
+        if (WillRetain)
+            result |= 0x20;
         if (WillFlag)
-            result |= 0b0000_0100;
+            result |= 0x04;
         if (CleanSession)
-            result |= 0b0000_0010;
+            result |= 0x02;
         if (WillFlag) // Only encode Will QoS if Will is set
-            result |= (byte)(((int)WillQoS & 0x03) << 3);
+            result |= (((int)WillQoS & 0x03) << 3);
 
-        return result;
+        return (byte)result;
     }
 
     public static ConnectFlags Decode(byte flags)
     {
         var result = new ConnectFlags
         {
-            UsernameFlag = (flags & 0b1000_0000) != 0,
-            PasswordFlag = (flags & 0b0100_0000) != 0,
-            WillRetain = (flags & 0b0010_0000) != 0,
-            WillFlag = (flags & 0b0000_0100) != 0,
-            CleanSession = (flags & 0b0000_0010) != 0
+            UsernameFlag = (flags & 0x80) == 0x80,
+            PasswordFlag = (flags & 0x40) == 0x40,
+            WillRetain = (flags & 0x20) == 0x20,
+            WillFlag = (flags & 0x04) == 0x04,
+            CleanSession = (flags & 0x02) == 0x02
         };
 
         if (result.WillFlag)
-            result.WillQoS = (QualityOfService)((flags & 0b0001_1000) >> 3);
+            result.WillQoS = (QualityOfService)((flags & 0x18) >> 3);
+        else if ((flags & 0x38) != 0) // reserved bit for Will 3,4,5
+        {
+            throw new ArgumentOutOfRangeException(nameof(flags), "[MQTT-3.1.2-11]");
+        }
 
         return result;
     }

src/TurboMqtt.Core/PacketTypes/DisconnectPacket.cs

@@ -11,6 +11,11 @@ namespace TurboMqtt.Core.PacketTypes;
 /// </summary>
 public sealed class DisconnectPacket : MqttPacket
 {
+    /// <summary>
+    /// Used for MQTT 3.1.1, since no additional properties are supported.
+    /// </summary>
+    internal static readonly DisconnectPacket Instance = new();
+
     public override MqttPacketType PacketType => MqttPacketType.Disconnect;
 
     // MQTT 5.0 - Optional Reason Code and Properties

src/TurboMqtt.Core/PacketTypes/PublishAckPacket.cs

@@ -46,7 +46,7 @@ public static string ReasonCodeToString(MqttPubAckReasonCode reasonCode)
 /// <summary>
 /// Used to acknowledge the receipt of a Publish packet.
 /// </summary>
-public sealed class PublishAckPacket : MqttPacketWithId
+public sealed class PubAckPacket : MqttPacketWithId
 {
     public override MqttPacketType PacketType => MqttPacketType.PubAck;
 

src/TurboMqtt.Core/PacketTypes/SubscribeAckPacket.cs

@@ -6,15 +6,15 @@
 
 namespace TurboMqtt.Core.PacketTypes;
 
-public enum MqttSubscribeReasonCode
+public enum MqttSubscribeReasonCode : byte
 {
     // Common reason codes in MQTT 3.1.1 and earlier versions (implicitly used, typically not explicitly specified in these versions)
     GrantedQoS0 = 0x00, // Maximum QoS 0, MQTT 3.0, 3.1.1
     GrantedQoS1 = 0x01, // Maximum QoS 1, MQTT 3.0, 3.1.1
     GrantedQoS2 = 0x02, // Maximum QoS 2, MQTT 3.0, 3.1.1
+    UnspecifiedError = 0x80, //  MQTT 3.0, 3.1.1, MQTT 5.0
 
     // MQTT 5.0 specific reason codes
-    UnspecifiedError = 0x80, // MQTT 5.0
     ImplementationSpecificError = 0x83, // MQTT 5.0
     NotAuthorized = 0x87, // MQTT 5.0
     TopicFilterInvalid = 0x8F, // MQTT 5.0
@@ -28,7 +28,7 @@ public enum MqttSubscribeReasonCode
 /// <summary>
 /// Represents the acknowledgement packet for a subscription request.
 /// </summary>
-public sealed class SubscribeAckPacket : MqttPacketWithId
+public sealed class SubAckPacket : MqttPacketWithId
 {
     public override MqttPacketType PacketType => MqttPacketType.SubAck;