aws_iot_mqtt_client_common_internal.c File Reference

MQTT client internal API definitions. More...

#include <aws_iot_mqtt_client.h>
#include "aws_iot_mqtt_client_common_internal.h"

Macros
#define	MAX_NO_OF_REMAINING_LENGTH_BYTES   4

Functions
size_t	aws_iot_mqtt_internal_write_len_to_buffer (unsigned char *buf, uint32_t length)
	Encodes the message length according to the MQTT algorithm. More...
IoT_Error_t	aws_iot_mqtt_internal_decode_remaining_length_from_buffer (unsigned char *buf, uint32_t *decodedLen, uint32_t *readBytesLen)
	Decodes the message length according to the MQTT algorithm. More...
uint32_t	aws_iot_mqtt_internal_get_final_packet_length_from_remaining_length (uint32_t rem_len)
	Calculates the length of the "remaining length" encoding. More...
uint16_t	aws_iot_mqtt_internal_read_uint16_t (unsigned char **pptr)
	Calculates uint16 packet id from two bytes read from the input buffer. More...
void	aws_iot_mqtt_internal_write_uint_16 (unsigned char **pptr, uint16_t anInt)
	Writes an integer as 2 bytes to an output buffer. More...
unsigned char	aws_iot_mqtt_internal_read_char (unsigned char **pptr)
	Reads one character from the input buffer. More...
void	aws_iot_mqtt_internal_write_char (unsigned char **pptr, unsigned char c)
	Writes one character to an output buffer. More...
void	aws_iot_mqtt_internal_write_utf8_string (unsigned char **pptr, const char *string, uint16_t stringLen)
	Writes a UTF-8 string into an MQTT packet. More...
IoT_Error_t	aws_iot_mqtt_internal_init_header (MQTTHeader *pHeader, MessageTypes message_type, QoS qos, uint8_t dup, uint8_t retained)
	Initialize the MQTTHeader structure. More...
IoT_Error_t	aws_iot_mqtt_internal_send_packet (AWS_IoT_Client *pClient, size_t length, Timer *pTimer)
	Send an MQTT packet on the network. More...
IoT_Error_t	aws_iot_mqtt_internal_cycle_read (AWS_IoT_Client *pClient, Timer *pTimer, uint8_t *pPacketType)
	Read an MQTT packet from the network. More...
IoT_Error_t	aws_iot_mqtt_internal_flushBuffers (AWS_IoT_Client *pClient)
	Flush incoming data from the MQTT client. More...
IoT_Error_t	aws_iot_mqtt_internal_wait_for_read (AWS_IoT_Client *pClient, uint8_t packetType, Timer *pTimer)
	Wait until a packet is read from the network. More...
IoT_Error_t	aws_iot_mqtt_internal_serialize_zero (unsigned char *pTxBuf, size_t txBufLen, MessageTypes packetType, size_t *pSerializedLength)

Detailed Description

MQTT client internal API definitions.

Macro Definition Documentation

MAX_NO_OF_REMAINING_LENGTH_BYTES

#define MAX_NO_OF_REMAINING_LENGTH_BYTES   4

Max length of packet header

Function Documentation

aws_iot_mqtt_internal_write_len_to_buffer()

size_t aws_iot_mqtt_internal_write_len_to_buffer	(	unsigned char *	buf,
		uint32_t	length
	)

Encodes the message length according to the MQTT algorithm.

Parameters

buf	the buffer into which the encoded data is written
length	the length to be encoded

Returns

the number of bytes written to buffer

aws_iot_mqtt_internal_decode_remaining_length_from_buffer()

IoT_Error_t aws_iot_mqtt_internal_decode_remaining_length_from_buffer	(	unsigned char *	buf,
		uint32_t *	decodedLen,
		uint32_t *	readBytesLen
	)

Decodes the message length according to the MQTT algorithm.

Parameters

buf	the buffer containing the message
decodedLen	value the decoded length returned
readBytesLen	output parameter for the number of bytes read from the socket

Returns

IoT_Error_t indicating decode status

aws_iot_mqtt_internal_get_final_packet_length_from_remaining_length()

uint32_t aws_iot_mqtt_internal_get_final_packet_length_from_remaining_length

(

uint32_t

rem_len

)

Calculates the length of the "remaining length" encoding.

Parameters

rem_len

"remaining length" to encode

Returns

length of the remaining length encoding

aws_iot_mqtt_internal_read_uint16_t()

uint16_t aws_iot_mqtt_internal_read_uint16_t

(

unsigned char **

pptr

)

Calculates uint16 packet id from two bytes read from the input buffer.

Checks Endianness at runtime

Parameters

pptr	pointer to the input buffer - incremented by the number of bytes used & returned

Returns

the value calculated

aws_iot_mqtt_internal_write_uint_16()

void aws_iot_mqtt_internal_write_uint_16	(	unsigned char **	pptr,
		uint16_t	anInt
	)

Writes an integer as 2 bytes to an output buffer.

Parameters

pptr	pointer to the output buffer - incremented by the number of bytes used & returned
anInt	the integer to write

aws_iot_mqtt_internal_read_char()

unsigned char aws_iot_mqtt_internal_read_char

(

unsigned char **

pptr

)

Reads one character from the input buffer.

Parameters

pptr	pointer to the input buffer - incremented by the number of bytes used & returned

Returns

the character read

aws_iot_mqtt_internal_write_char()

void aws_iot_mqtt_internal_write_char	(	unsigned char **	pptr,
		unsigned char	c
	)

Writes one character to an output buffer.

Parameters

pptr	pointer to the output buffer - incremented by the number of bytes used & returned
c	the character to write

aws_iot_mqtt_internal_write_utf8_string()

void aws_iot_mqtt_internal_write_utf8_string	(	unsigned char **	pptr,
		const char *	string,
		uint16_t	stringLen
	)

Writes a UTF-8 string into an MQTT packet.

Parameters

pptr	Where the string should be written
string	The string to write
stringLen	Length to write

aws_iot_mqtt_internal_init_header()

IoT_Error_t aws_iot_mqtt_internal_init_header	(	MQTTHeader *	pHeader,
		MessageTypes	message_type,
		QoS	qos,
		uint8_t	dup,
		uint8_t	retained
	)

Initialize the MQTTHeader structure.

Used to ensure that Header bits are always initialized using the proper mappings. No Endianness issues here since the individual fields are all less than a byte. Also generates no warnings since all fields are initialized using hex constants.

Parameters

pHeader	Header to initialize
message_type	MQTT packet type
qos	Quality of service for packet
dup	DUP flag of a publish
retained	RETAIN flag of a publish

Returns

Returns SUCCESS unless an invalid packet type is given.

aws_iot_mqtt_internal_send_packet()

IoT_Error_t aws_iot_mqtt_internal_send_packet	(	AWS_IoT_Client *	pClient,
		size_t	length,
		Timer *	pTimer
	)

Send an MQTT packet on the network.

Parameters

pClient	MQTT client which holds packet
length	Length of packet to send
pTimer	Amount of time allowed to send packet

Returns

IoT_Error_t of send status

aws_iot_mqtt_internal_cycle_read()

IoT_Error_t aws_iot_mqtt_internal_cycle_read	(	AWS_IoT_Client *	pClient,
		Timer *	pTimer,
		uint8_t *	pPacketType
	)

Read an MQTT packet from the network.

Parameters

pClient	MQTT client
pTimer	Amount of time allowed to read packet
pPacketType	Output parameter for packet read from network

Returns

IoT_Error_t of read status

aws_iot_mqtt_internal_flushBuffers()

IoT_Error_t aws_iot_mqtt_internal_flushBuffers

(

AWS_IoT_Client *

pClient

)

Flush incoming data from the MQTT client.

Parameters

pClient

Client with data to flush

Returns

Always returns SUCCESS

aws_iot_mqtt_internal_wait_for_read()

IoT_Error_t aws_iot_mqtt_internal_wait_for_read	(	AWS_IoT_Client *	pClient,
		uint8_t	packetType,
		Timer *	pTimer
	)

Wait until a packet is read from the network.

Only used in single-threaded mode where one command at a time is in process

Parameters

pClient	MQTT client
packetType	MQTT packet to read
pTimer	Amount of time allowed to read packet

Returns

IoT_Error_t of read status

aws_iot_mqtt_internal_serialize_zero()

IoT_Error_t aws_iot_mqtt_internal_serialize_zero	(	unsigned char *	pTxBuf,
		size_t	txBufLen,
		MessageTypes	packetType,
		size_t *	pSerializedLength
	)

Serializes a 0-length packet into the supplied buffer, ready for writing to a socket

Parameters

pTxBuf	the buffer into which the packet will be serialized
txBufLen	the length in bytes of the supplied buffer, to avoid overruns
packetType	the message type
pSerializedLength	length

Returns

IoT_Error_t indicating function execution status