Packet DecodePacketInternal(IByteBuffer buffer, int packetSignature, ref int remainingLength, IChannelHandlerContext context)
{
if (Signatures.IsPublish(packetSignature))
{
var qualityOfService = (QualityOfService)((packetSignature >> 1) & 0x3); // take bits #1 and #2 ONLY and convert them into QoS value
if (qualityOfService == QualityOfService.Reserved)
{
throw new DecoderException($"Unexpected QoS value of {(int)qualityOfService} for {PacketType.PUBLISH} packet.");
}
bool duplicate = (packetSignature & 0x8) == 0x8; // test bit#3
bool retain = (packetSignature & 0x1) != 0; // test bit#0
var packet = new PublishPacket(qualityOfService, duplicate, retain);
DecodePublishPacket(buffer, packet, ref remainingLength);
return(packet);
}
switch (packetSignature) // strict match checks for valid message type + correct values in flags part
{
case Signatures.PubAck:
var pubAckPacket = new PubAckPacket();
DecodePacketIdVariableHeader(buffer, pubAckPacket, ref remainingLength);
return(pubAckPacket);
case Signatures.PubRec:
var pubRecPacket = new PubRecPacket();
DecodePacketIdVariableHeader(buffer, pubRecPacket, ref remainingLength);
return(pubRecPacket);
case Signatures.PubRel:
var pubRelPacket = new PubRelPacket();
DecodePacketIdVariableHeader(buffer, pubRelPacket, ref remainingLength);
return(pubRelPacket);
case Signatures.PubComp:
var pubCompPacket = new PubCompPacket();
DecodePacketIdVariableHeader(buffer, pubCompPacket, ref remainingLength);
return(pubCompPacket);
case Signatures.PingReq:
this.ValidateServerPacketExpected(packetSignature);
return(PingReqPacket.Instance);
case Signatures.Subscribe:
this.ValidateServerPacketExpected(packetSignature);
var subscribePacket = new SubscribePacket();
DecodePacketIdVariableHeader(buffer, subscribePacket, ref remainingLength);
DecodeSubscribePayload(buffer, subscribePacket, ref remainingLength);
return(subscribePacket);
case Signatures.Unsubscribe:
this.ValidateServerPacketExpected(packetSignature);
var unsubscribePacket = new UnsubscribePacket();
DecodePacketIdVariableHeader(buffer, unsubscribePacket, ref remainingLength);
DecodeUnsubscribePayload(buffer, unsubscribePacket, ref remainingLength);
return(unsubscribePacket);
case Signatures.Connect:
this.ValidateServerPacketExpected(packetSignature);
var connectPacket = new ConnectPacket();
DecodeConnectPacket(buffer, connectPacket, ref remainingLength, context);
return(connectPacket);
case Signatures.Disconnect:
this.ValidateServerPacketExpected(packetSignature);
return(DisconnectPacket.Instance);
case Signatures.ConnAck:
this.ValidateClientPacketExpected(packetSignature);
var connAckPacket = new ConnAckPacket();
DecodeConnAckPacket(buffer, connAckPacket, ref remainingLength);
return(connAckPacket);
case Signatures.SubAck:
this.ValidateClientPacketExpected(packetSignature);
var subAckPacket = new SubAckPacket();
DecodePacketIdVariableHeader(buffer, subAckPacket, ref remainingLength);
DecodeSubAckPayload(buffer, subAckPacket, ref remainingLength);
return(subAckPacket);
case Signatures.UnsubAck:
this.ValidateClientPacketExpected(packetSignature);
var unsubAckPacket = new UnsubAckPacket();
DecodePacketIdVariableHeader(buffer, unsubAckPacket, ref remainingLength);
return(unsubAckPacket);
case Signatures.PingResp:
this.ValidateClientPacketExpected(packetSignature);
return(PingRespPacket.Instance);
default:
throw new DecoderException($"First packet byte value of `{packetSignature}` is invalid.");
}
}