Implements functions that generate and decode MQTT network packets. More...

#include "iot_config.h"
#include <string.h>
#include <limits.h>
#include "private/iot_mqtt_internal.h"
#include "private/iot_mqtt_helper.h"
#include "platform/iot_threads.h"
#include "iot_atomic.h"

Functions
static IotMqttError_t	_decodeSubackStatus (size_t statusCount, const uint8_t pStatusStart, const _mqttPacket_t pSuback)
	Decode the status bytes of a SUBACK packet. More...

static IotMqttError_t	_checkRemainingLength (const _mqttPacket_t *pPublish, IotMqttQos_t qos, size_t qos0Minimum)
	Check the remaining length against some value for QoS 0 or QoS 1/2. More...

uint8_t	_IotMqtt_GetPacketType (IotNetworkConnection_t pNetworkConnection, const IotNetworkInterface_t *pNetworkInterface)
	Get the MQTT packet type from a stream of bytes off the network. More...

size_t	_IotMqtt_GetRemainingLength (IotNetworkConnection_t pNetworkConnection, const IotNetworkInterface_t *pNetworkInterface)
	Get the remaining length from a stream of bytes off the network. More...

IotMqttError_t	_IotMqtt_SerializeConnect (const IotMqttConnectInfo_t pConnectInfo, uint8_t pConnectPacket, size_t pPacketSize)
	Generate a CONNECT packet from the given parameters. More...

IotMqttError_t	_IotMqtt_DeserializeConnack (_mqttPacket_t *pConnack)
	Deserialize a CONNACK packet. More...

IotMqttError_t	_IotMqtt_SerializePublish (const IotMqttPublishInfo_t pPublishInfo, uint8_t pPublishPacket, size_t pPacketSize, uint16_t pPacketIdentifier, uint8_t *pPacketIdentifierHigh)
	Generate a PUBLISH packet from the given parameters. More...

void	_IotMqtt_PublishSetDup (uint8_t pPublishPacket, uint8_t pPacketIdentifierHigh, uint16_t *pNewPacketIdentifier)
	Set the DUP bit in a QoS 1 PUBLISH packet. More...

IotMqttError_t	_IotMqtt_DeserializePublish (_mqttPacket_t *pPublish)
	Deserialize a PUBLISH packet received from the server. More...

IotMqttError_t	_IotMqtt_SerializePuback (uint16_t packetIdentifier, uint8_t *pPubackPacket, size_t pPacketSize)
	Generate a PUBACK packet for the given packet identifier. More...

IotMqttError_t	_IotMqtt_DeserializePuback (_mqttPacket_t *pPuback)
	Deserialize a PUBACK packet. More...

IotMqttError_t	_IotMqtt_SerializeSubscribe (const IotMqttSubscription_t pSubscriptionList, size_t subscriptionCount, uint8_t pSubscribePacket, size_t pPacketSize, uint16_t *pPacketIdentifier)
	Generate a SUBSCRIBE packet from the given parameters. More...

IotMqttError_t	_IotMqtt_DeserializeSuback (_mqttPacket_t *pSuback)
	Deserialize a SUBACK packet. More...

IotMqttError_t	_IotMqtt_SerializeUnsubscribe (const IotMqttSubscription_t pSubscriptionList, size_t subscriptionCount, uint8_t pUnsubscribePacket, size_t pPacketSize, uint16_t *pPacketIdentifier)
	Generate an UNSUBSCRIBE packet from the given parameters. More...

IotMqttError_t	_IotMqtt_DeserializeUnsuback (_mqttPacket_t *pUnsuback)
	Deserialize a UNSUBACK packet. More...

IotMqttError_t	_IotMqtt_SerializePingreq (uint8_t *pPingreqPacket, size_t pPacketSize)
	Generate a PINGREQ packet. More...

IotMqttError_t	_IotMqtt_DeserializePingresp (_mqttPacket_t *pPingresp)
	Deserialize a PINGRESP packet. More...

IotMqttError_t	_IotMqtt_SerializeDisconnect (uint8_t *pDisconnectPacket, size_t pPacketSize)
	Generate a DISCONNECT packet. More...

void	_IotMqtt_FreePacket (uint8_t *pPacket)
	Free a packet generated by the serializer. More...

Detailed Description

Implements functions that generate and decode MQTT network packets.

Function Documentation

◆ _decodeSubackStatus()

static IotMqttError_t _decodeSubackStatus	(	size_t	statusCount,
		const uint8_t *	pStatusStart,
		const _mqttPacket_t *	pSuback
	)

static

Decode the status bytes of a SUBACK packet.

Parameters

[in]	statusCount	Number of status bytes in the SUBACK.
[in]	pStatusStart	The first status byte in the SUBACK.
[in]	pSuback	The SUBACK packet received from the network.

Returns: IOT_MQTT_SUCCESS, IOT_MQTT_SERVER_REFUSED, or IOT_MQTT_BAD_RESPONSE.

◆ _checkRemainingLength()

static IotMqttError_t _checkRemainingLength	(	const _mqttPacket_t *	pPublish,
		IotMqttQos_t	qos,
		size_t	qos0Minimum
	)

static

Check the remaining length against some value for QoS 0 or QoS 1/2.

The remaining length for a QoS 1/2 will always be two greater than for a QoS 0.

Parameters

[in]	pPublish	Pointer to an MQTT packet struct representing a PUBLISH.
[in]	qos	The QoS of the PUBLISH.
[in]	qos0Minimum	Minimum possible remaining length for a QoS 0 PUBLISH.

Returns: IOT_MQTT_SUCCESS or IOT_MQTT_BAD_RESPONSE.

◆ _IotMqtt_GetPacketType()

uint8_t _IotMqtt_GetPacketType	(	IotNetworkConnection_t	pNetworkConnection,
		const IotNetworkInterface_t *	pNetworkInterface
	)

Get the MQTT packet type from a stream of bytes off the network.

Parameters

[in]	pNetworkConnection	Reference to the network connection.
[in]	pNetworkInterface	Function pointers used to interact with the network.

Returns: One of the server-to-client MQTT packet types.

Note: This function is only used for incoming packets, and may not work correctly for outgoing packets.

◆ _IotMqtt_GetRemainingLength()

size_t _IotMqtt_GetRemainingLength	(	IotNetworkConnection_t	pNetworkConnection,
		const IotNetworkInterface_t *	pNetworkInterface
	)

Get the remaining length from a stream of bytes off the network.

Parameters

[in]	pNetworkConnection	Reference to the network connection.
[in]	pNetworkInterface	Function pointers used to interact with the network.

Returns: The remaining length; MQTT_REMAINING_LENGTH_INVALID on error.

◆ _IotMqtt_SerializeConnect()

IotMqttError_t _IotMqtt_SerializeConnect	(	const IotMqttConnectInfo_t *	pConnectInfo,
		uint8_t **	pConnectPacket,
		size_t *	pPacketSize
	)

Generate a CONNECT packet from the given parameters.

Parameters

[in]	pConnectInfo	User-provided CONNECT information.
[out]	pConnectPacket	Where the CONNECT packet is written.
[out]	pPacketSize	Size of the packet written to `pConnectPacket`.

Returns: IOT_MQTT_SUCCESS or IOT_MQTT_NO_MEMORY.

◆ _IotMqtt_DeserializeConnack()

IotMqttError_t _IotMqtt_DeserializeConnack ( _mqttPacket_t * pConnack )

Deserialize a CONNACK packet.

Converts the packet from a stream of bytes to an IotMqttError_t. Also prints out debug log messages about the packet.

Parameters

[in,out] pConnack Pointer to an MQTT packet struct representing a CONNACK.

Returns: IOT_MQTT_SUCCESS if CONNACK specifies that CONNECT was accepted; IOT_MQTT_SERVER_REFUSED if CONNACK specifies that CONNECT was rejected; IOT_MQTT_BAD_RESPONSE if the CONNACK packet doesn't follow MQTT spec.

◆ _IotMqtt_SerializePublish()

IotMqttError_t _IotMqtt_SerializePublish	(	const IotMqttPublishInfo_t *	pPublishInfo,
		uint8_t **	pPublishPacket,
		size_t *	pPacketSize,
		uint16_t *	pPacketIdentifier,
		uint8_t **	pPacketIdentifierHigh
	)

Generate a PUBLISH packet from the given parameters.

Parameters

[in]	pPublishInfo	User-provided PUBLISH information.
[out]	pPublishPacket	Where the PUBLISH packet is written.
[out]	pPacketSize	Size of the packet written to `pPublishPacket`.
[out]	pPacketIdentifier	The packet identifier generated for this PUBLISH.
[out]	pPacketIdentifierHigh	Where the high byte of the packet identifier is written.

Returns: IOT_MQTT_SUCCESS or IOT_MQTT_NO_MEMORY.

◆ _IotMqtt_PublishSetDup()

void _IotMqtt_PublishSetDup	(	uint8_t *	pPublishPacket,
		uint8_t *	pPacketIdentifierHigh,
		uint16_t *	pNewPacketIdentifier
	)

Set the DUP bit in a QoS 1 PUBLISH packet.

Parameters

[in]	pPublishPacket	Pointer to the PUBLISH packet to modify.
[in]	pPacketIdentifierHigh	The high byte of any packet identifier to modify.
[out]	pNewPacketIdentifier	Since AWS IoT does not support the DUP flag, a new packet identifier is generated and should be written here. This parameter is only used when connected to an AWS IoT MQTT server.

Note: See IotMqttPublishInfo_t for caveats with retransmission to the AWS IoT MQTT server.

◆ _IotMqtt_DeserializePublish()

IotMqttError_t _IotMqtt_DeserializePublish ( _mqttPacket_t * pPublish )

Deserialize a PUBLISH packet received from the server.

Converts the packet from a stream of bytes to an IotMqttPublishInfo_t and extracts the packet identifier. Also prints out debug log messages about the packet.

Parameters

[in,out] pPublish Pointer to an MQTT packet struct representing a PUBLISH.

Returns: IOT_MQTT_SUCCESS if PUBLISH is valid; IOT_MQTT_BAD_RESPONSE if the PUBLISH packet doesn't follow MQTT spec.

◆ _IotMqtt_SerializePuback()

IotMqttError_t _IotMqtt_SerializePuback	(	uint16_t	packetIdentifier,
		uint8_t **	pPubackPacket,
		size_t *	pPacketSize
	)

Generate a PUBACK packet for the given packet identifier.

Parameters

[in]	packetIdentifier	The packet identifier to place in PUBACK.
[out]	pPubackPacket	Where the PUBACK packet is written.
[out]	pPacketSize	Size of the packet written to `pPubackPacket`.

Returns: IOT_MQTT_SUCCESS or IOT_MQTT_NO_MEMORY.

◆ _IotMqtt_DeserializePuback()

IotMqttError_t _IotMqtt_DeserializePuback ( _mqttPacket_t * pPuback )

Deserialize a PUBACK packet.

Converts the packet from a stream of bytes to an IotMqttError_t and extracts the packet identifier. Also prints out debug log messages about the packet.

Parameters

[in,out] pPuback Pointer to an MQTT packet struct representing a PUBACK.

Returns: IOT_MQTT_SUCCESS if PUBACK is valid; IOT_MQTT_BAD_RESPONSE if the PUBACK packet doesn't follow MQTT spec.

◆ _IotMqtt_SerializeSubscribe()

IotMqttError_t _IotMqtt_SerializeSubscribe	(	const IotMqttSubscription_t *	pSubscriptionList,
		size_t	subscriptionCount,
		uint8_t **	pSubscribePacket,
		size_t *	pPacketSize,
		uint16_t *	pPacketIdentifier
	)

Generate a SUBSCRIBE packet from the given parameters.

Parameters

[in]	pSubscriptionList	User-provided array of subscriptions.
[in]	subscriptionCount	Size of `pSubscriptionList`.
[out]	pSubscribePacket	Where the SUBSCRIBE packet is written.
[out]	pPacketSize	Size of the packet written to `pSubscribePacket`.
[out]	pPacketIdentifier	The packet identifier generated for this SUBSCRIBE.

Returns: IOT_MQTT_SUCCESS or IOT_MQTT_NO_MEMORY.

◆ _IotMqtt_DeserializeSuback()

IotMqttError_t _IotMqtt_DeserializeSuback ( _mqttPacket_t * pSuback )

Deserialize a SUBACK packet.

Converts the packet from a stream of bytes to an IotMqttError_t and extracts the packet identifier. Also prints out debug log messages about the packet.

Parameters

[in,out] pSuback Pointer to an MQTT packet struct representing a SUBACK.

Returns: IOT_MQTT_SUCCESS if SUBACK is valid; IOT_MQTT_BAD_RESPONSE if the SUBACK packet doesn't follow MQTT spec.

◆ _IotMqtt_SerializeUnsubscribe()

IotMqttError_t _IotMqtt_SerializeUnsubscribe	(	const IotMqttSubscription_t *	pSubscriptionList,
		size_t	subscriptionCount,
		uint8_t **	pUnsubscribePacket,
		size_t *	pPacketSize,
		uint16_t *	pPacketIdentifier
	)

Generate an UNSUBSCRIBE packet from the given parameters.

Parameters

[in]	pSubscriptionList	User-provided array of subscriptions to remove.
[in]	subscriptionCount	Size of `pSubscriptionList`.
[out]	pUnsubscribePacket	Where the UNSUBSCRIBE packet is written.
[out]	pPacketSize	Size of the packet written to `pUnsubscribePacket`.
[out]	pPacketIdentifier	The packet identifier generated for this UNSUBSCRIBE.

Returns: IOT_MQTT_SUCCESS or IOT_MQTT_NO_MEMORY.

◆ _IotMqtt_DeserializeUnsuback()

IotMqttError_t _IotMqtt_DeserializeUnsuback ( _mqttPacket_t * pUnsuback )

Deserialize a UNSUBACK packet.

Converts the packet from a stream of bytes to an IotMqttError_t and extracts the packet identifier. Also prints out debug log messages about the packet.

Parameters

[in,out] pUnsuback Pointer to an MQTT packet struct representing an UNSUBACK.

Returns: IOT_MQTT_SUCCESS if UNSUBACK is valid; IOT_MQTT_BAD_RESPONSE if the UNSUBACK packet doesn't follow MQTT spec.

◆ _IotMqtt_SerializePingreq()

IotMqttError_t _IotMqtt_SerializePingreq	(	uint8_t **	pPingreqPacket,
		size_t *	pPacketSize
	)

Generate a PINGREQ packet.

Parameters

[out]	pPingreqPacket	Where the PINGREQ packet is written.
[out]	pPacketSize	Size of the packet written to `pPingreqPacket`.

Returns: Always returns IOT_MQTT_SUCCESS.

◆ _IotMqtt_DeserializePingresp()

IotMqttError_t _IotMqtt_DeserializePingresp ( _mqttPacket_t * pPingresp )

Deserialize a PINGRESP packet.

Converts the packet from a stream of bytes to an IotMqttError_t. Also prints out debug log messages about the packet.

Parameters

[in,out] pPingresp Pointer to an MQTT packet struct representing a PINGRESP.

Returns: IOT_MQTT_SUCCESS if PINGRESP is valid; IOT_MQTT_BAD_RESPONSE if the PINGRESP packet doesn't follow MQTT spec.

◆ _IotMqtt_SerializeDisconnect()

IotMqttError_t _IotMqtt_SerializeDisconnect	(	uint8_t **	pDisconnectPacket,
		size_t *	pPacketSize
	)

Generate a DISCONNECT packet.

Parameters

[out]	pDisconnectPacket	Where the DISCONNECT packet is written.
[out]	pPacketSize	Size of the packet written to `pDisconnectPacket`.

Returns: Always returns IOT_MQTT_SUCCESS.

◆ _IotMqtt_FreePacket()

void _IotMqtt_FreePacket ( uint8_t * pPacket )

Free a packet generated by the serializer.

Parameters

[in] pPacket The packet to free.

Functions

Detailed Description

Function Documentation

◆ _decodeSubackStatus()

◆ _checkRemainingLength()

◆ _IotMqtt_GetPacketType()

◆ _IotMqtt_GetRemainingLength()

◆ _IotMqtt_SerializeConnect()

◆ _IotMqtt_DeserializeConnack()

◆ _IotMqtt_SerializePublish()

◆ _IotMqtt_PublishSetDup()

◆ _IotMqtt_DeserializePublish()

◆ _IotMqtt_SerializePuback()

◆ _IotMqtt_DeserializePuback()

◆ _IotMqtt_SerializeSubscribe()

◆ _IotMqtt_DeserializeSuback()

◆ _IotMqtt_SerializeUnsubscribe()

◆ _IotMqtt_DeserializeUnsuback()

◆ _IotMqtt_SerializePingreq()

◆ _IotMqtt_DeserializePingresp()

◆ _IotMqtt_SerializeDisconnect()

◆ _IotMqtt_FreePacket()