Module mqttbytes 

This module is the place where all the protocol specifics gets abstracted out and creates a structures which are common across protocols. Since, MQTT is the core protocol that this broker supports, a lot of structs closely map to what MQTT specifies in its protocol

Structs

Auth

Used to perform extended authentication exchange

Codec

MQTT v4 codec

ConnAck

Acknowledgement to connect packet

ConnAckProperties

Connect

Connection packet initiated by the client

ConnectProperties

Disconnect

DisconnectProperties

Filter

Subscription filter

FixedHeader

Packet type from a byte

LastWill

LastWill that broker forwards on behalf of the client

LastWillProperties

Login

PingReq

PingResp

PubAck

Acknowledgement to QoS1 publish

PubAckProperties

PubComp

QoS2 Assured publish complete, in response to PUBREL packet

PubCompProperties

PubRec

Acknowledgement to QoS1 publish

PubRecProperties

PubRel

QoS2 Publish release, in response to PUBREC packet

PubRelProperties

Publish

Publish packet

PublishProperties

SubAck

Acknowledgement to subscribe

SubAckProperties

Subscribe

Subscription packet

SubscribeProperties

UnsubAck

Acknowledgement to unsubscribe

UnsubAckProperties

Unsubscribe

Unsubscribe packet

UnsubscribeProperties

Enums

ConnectReturnCode

Return code in connack

DisconnectReasonCode

Packet

PacketType

MQTT packet type

PubAckReason

Return code in puback

PubCompReason

Return code in PubComp

PubRecReason

Return code in PubRec

PubRelReason

Return code in PubRel

RetainForwardRule

SubscribeReasonCode

UnsubAckReason

Functions

check

Checks if the stream has enough bytes to frame a packet and returns fixed header only if a packet can be framed with existing bytes in the stream. The passed stream doesn’t modify parent stream’s cursor. If this function returned an error, next check on the same parent stream is forced start with cursor at 0 again (Iter is owned. Only Iter’s cursor is changed internally)