functions to deal with reading and writing of MQTT packets from and to sockets More...

#include "MQTTPacket.h"
#include "Log.h"
#include "MQTTPersistence.h"
#include "Messages.h"
#include "StackTrace.h"
#include "WebSocket.h"
#include "MQTTTime.h"
#include <stdlib.h>
#include <string.h>
#include "Heap.h"

Include dependency graph for MQTTPacket.c:

Go to the source code of this file.

Macros
#define	MAX_NO_OF_REMAINING_LENGTH_BYTES 4

#define	MAX_NO_OF_REMAINING_LENGTH_BYTES 4

#define	min(A, B) ( (A) < (B) ? (A):(B))

Functions
int	bufchar (char *c, int count)

int	MQTTLenStringRead (MQTTLenString lenstring, char pptr, char enddata)

void *	MQTTPacket_ack (int MQTTVersion, unsigned char aHeader, char *data, size_t datalen)

int	MQTTPacket_decode (networkHandles net, size_t value)

int	MQTTPacket_decodeBuf (char buf, unsigned int value)

int	MQTTPacket_encode (char *buf, size_t length)

void *	MQTTPacket_Factory (int MQTTVersion, networkHandles net, int error)

void	MQTTPacket_free_packet (MQTTPacket *pack)

void	MQTTPacket_freeAck (Ack *pack)

void	MQTTPacket_freePublish (Publish *pack)

void	MQTTPacket_freeSuback (Suback *pack)

void	MQTTPacket_freeUnsuback (Unsuback *pack)

void *	MQTTPacket_header_only (int MQTTVersion, unsigned char aHeader, char *data, size_t datalen)

const char *	MQTTPacket_name (int ptype)

void *	MQTTPacket_publish (int MQTTVersion, unsigned char aHeader, char *data, size_t datalen)

int	MQTTPacket_send (networkHandles net, Header header, char buffer, size_t buflen, int freeData, int MQTTVersion)

static int	MQTTPacket_send_ack (int MQTTVersion, int type, int msgid, int dup, networkHandles *net)

int	MQTTPacket_send_disconnect (Clients client, enum MQTTReasonCodes reason, MQTTProperties props)

int	MQTTPacket_send_puback (int MQTTVersion, int msgid, networkHandles net, const char clientID)

int	MQTTPacket_send_pubcomp (int MQTTVersion, int msgid, networkHandles net, const char clientID)

int	MQTTPacket_send_publish (Publish pack, int dup, int qos, int retained, networkHandles net, const char *clientID)

int	MQTTPacket_send_pubrec (int MQTTVersion, int msgid, networkHandles net, const char clientID)

int	MQTTPacket_send_pubrel (int MQTTVersion, int msgid, int dup, networkHandles net, const char clientID)

int	MQTTPacket_sends (networkHandles net, Header header, PacketBuffers bufs, int MQTTVersion)

int	MQTTPacket_VBIdecode (int(getcharfn)(char , int), unsigned int *value)

int	MQTTPacket_VBIlen (int rem_len)

unsigned char	readChar (char **pptr)

int	readInt (char **pptr)

int	readInt4 (char **pptr)

char *	readUTF (char *pptr, char enddata)

static char *	readUTFlen (char *pptr, char enddata, int *len)

void	writeChar (char **pptr, char c)

void	writeData (char *pptr, const void data, int datalen)

void	writeInt (char **pptr, int anInt)

void	writeInt4 (char **pptr, int anInt)

void	writeMQTTLenString (char **pptr, MQTTLenString lenstring)

void	writeUTF (char *pptr, const char string)

Variables
static char *	bufptr

const char **	MQTTClient_packet_names = packet_names

pf	new_packets []

static const char *	packet_names []

Detailed Description

functions to deal with reading and writing of MQTT packets from and to sockets

Some other related functions are in the MQTTPacketOut module

Definition in file MQTTPacket.c.

Macro Definition Documentation

#define MAX_NO_OF_REMAINING_LENGTH_BYTES 4

#define min	(	A,
		B
	)	( (A) < (B) ? (A):(B))

Definition at line 44 of file MQTTPacket.c.

Function Documentation

int bufchar	(	char *	c,
		int	count
	)

Definition at line 1042 of file MQTTPacket.c.

int MQTTLenStringRead	(	MQTTLenString *	lenstring,
		char **	pptr,
		char *	enddata
	)

Definition at line 962 of file MQTTPacket.c.

void* MQTTPacket_ack	(	int	MQTTVersion,
		unsigned char	aHeader,
		char *	data,
		size_t	datalen
	)

Function used in the new packets table to create acknowledgement packets.

Parameters

MQTTVersion	the version of MQTT being used
aHeader	the MQTT header byte
data	the rest of the packet
datalen	the length of the rest of the packet

Returns: pointer to the packet structure

Definition at line 783 of file MQTTPacket.c.

int MQTTPacket_decode	(	networkHandles *	net,
		size_t *	value
	)

Decodes the message length according to the MQTT algorithm

Parameters

socket	the socket from which to read the bytes
value	the decoded length returned

Returns: the number of bytes read from the socket

Definition at line 325 of file MQTTPacket.c.

int MQTTPacket_decodeBuf	(	char *	buf,
		unsigned int *	value
	)

Definition at line 1052 of file MQTTPacket.c.

int MQTTPacket_encode	(	char *	buf,
		size_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

Definition at line 297 of file MQTTPacket.c.

void* MQTTPacket_Factory	(	int	MQTTVersion,
		networkHandles *	net,
		int *	error
	)

Reads one MQTT packet from a socket.

Parameters

socket	a socket from which to read an MQTT packet
error	pointer to the error code which is completed if no packet is returned

Returns: the packet structure or NULL if there was an error

Definition at line 103 of file MQTTPacket.c.

void MQTTPacket_free_packet ( MQTTPacket * pack )

Free allocated storage for a various packet tyoes

Parameters

pack	pointer to the suback packet structure

Definition at line 905 of file MQTTPacket.c.

void MQTTPacket_freeAck ( Ack * pack )

Free allocated storage for an ack packet.

Parameters

pack	pointer to the publish packet structure

Definition at line 617 of file MQTTPacket.c.

void MQTTPacket_freePublish ( Publish * pack )

Free allocated storage for a publish packet.

Parameters

pack	pointer to the publish packet structure

Definition at line 601 of file MQTTPacket.c.

void MQTTPacket_freeSuback ( Suback * pack )

Free allocated storage for a suback packet.

Parameters

pack	pointer to the suback packet structure

Definition at line 684 of file MQTTPacket.c.

void MQTTPacket_freeUnsuback ( Unsuback * pack )

Free allocated storage for a suback packet.

Parameters

pack	pointer to the suback packet structure

Definition at line 700 of file MQTTPacket.c.

void* MQTTPacket_header_only	(	int	MQTTVersion,
		unsigned char	aHeader,
		char *	data,
		size_t	datalen
	)

Function used in the new packets table to create packets which have only a header.

Parameters

MQTTVersion	the version of MQTT
aHeader	the MQTT header byte
data	the rest of the packet
datalen	the length of the rest of the packet

Returns: pointer to the packet structure

Definition at line 495 of file MQTTPacket.c.

const char* MQTTPacket_name ( int ptype )

Converts an MQTT packet code into its name

Parameters

ptype packet code

Returns: the corresponding string, or "UNKNOWN"

Definition at line 65 of file MQTTPacket.c.

void* MQTTPacket_publish	(	int	MQTTVersion,
		unsigned char	aHeader,
		char *	data,
		size_t	datalen
	)

Function used in the new packets table to create publish packets.

Parameters

MQTTVersion
aHeader	the MQTT header byte
data	the rest of the packet
datalen	the length of the rest of the packet

Returns: pointer to the packet structure

Definition at line 553 of file MQTTPacket.c.

int MQTTPacket_send	(	networkHandles *	net,
		Header	header,
		char *	buffer,
		size_t	buflen,
		int	freeData,
		int	MQTTVersion
	)

Sends an MQTT packet in one system call write

Parameters

socket	the socket to which to write the data
header	the one-byte MQTT header
buffer	the rest of the buffer to write (not including remaining length)
buflen	the length of the data in buffer to be written
MQTTVersion	the version of MQTT being used

Returns: the completion code (TCPSOCKET_COMPLETE etc)

Definition at line 190 of file MQTTPacket.c.

static int MQTTPacket_send_ack	(	int	MQTTVersion,
		int	type,
		int	msgid,
		int	dup,
		networkHandles *	net
	)

static

Send an MQTT acknowledgement packet down a socket.

Parameters

MQTTVersion	the version of MQTT being used
type	the MQTT packet type e.g. SUBACK
msgid	the MQTT message id to use
dup	boolean - whether to set the MQTT DUP flag
net	the network handle to send the data to

Returns: the completion code (e.g. TCPSOCKET_COMPLETE)

Definition at line 636 of file MQTTPacket.c.

int MQTTPacket_send_disconnect	(	Clients *	client,
		enum MQTTReasonCodes	reason,
		MQTTProperties *	props
	)

Send an MQTT disconnect packet down a socket.

Parameters

socket the open socket to send the data to

Returns: the completion code (e.g. TCPSOCKET_COMPLETE)

Definition at line 508 of file MQTTPacket.c.

int MQTTPacket_send_puback	(	int	MQTTVersion,
		int	msgid,
		networkHandles *	net,
		const char *	clientID
	)

Send an MQTT PUBACK packet down a socket.

Parameters

MQTTVersion	the version of MQTT being used
msgid	the MQTT message id to use
socket	the open socket to send the data to
clientID	the string client identifier, only used for tracing

Returns: the completion code (e.g. TCPSOCKET_COMPLETE)

Definition at line 668 of file MQTTPacket.c.

int MQTTPacket_send_pubcomp	(	int	MQTTVersion,
		int	msgid,
		networkHandles *	net,
		const char *	clientID
	)

Send an MQTT PUBCOMP packet down a socket.

Parameters

MQTTVersion	the version of MQTT being used
msgid	the MQTT message id to use
socket	the open socket to send the data to
clientID	the string client identifier, only used for tracing

Returns: the completion code (e.g. TCPSOCKET_COMPLETE)

Definition at line 763 of file MQTTPacket.c.

int MQTTPacket_send_publish	(	Publish *	pack,
		int	dup,
		int	qos,
		int	retained,
		networkHandles *	net,
		const char *	clientID
	)

Send an MQTT PUBLISH packet down a socket.

Parameters

pack	a structure from which to get some values to use, e.g topic, payload
dup	boolean - whether to set the MQTT DUP flag
qos	the value to use for the MQTT QoS setting
retained	boolean - whether to set the MQTT retained flag
socket	the open socket to send the data to
clientID	the string client identifier, only used for tracing

Returns: the completion code (e.g. TCPSOCKET_COMPLETE)

Definition at line 835 of file MQTTPacket.c.

int MQTTPacket_send_pubrec	(	int	MQTTVersion,
		int	msgid,
		networkHandles *	net,
		const char *	clientID
	)

Send an MQTT PUBREC packet down a socket.

Parameters

MQTTVersion	the version of MQTT being used
msgid	the MQTT message id to use
socket	the open socket to send the data to
clientID	the string client identifier, only used for tracing

Returns: the completion code (e.g. TCPSOCKET_COMPLETE)

Definition at line 722 of file MQTTPacket.c.

int MQTTPacket_send_pubrel	(	int	MQTTVersion,
		int	msgid,
		int	dup,
		networkHandles *	net,
		const char *	clientID
	)

Send an MQTT PUBREL packet down a socket.

Parameters

MQTTVersion	the version of MQTT being used
msgid	the MQTT message id to use
dup	boolean - whether to set the MQTT DUP flag
socket	the open socket to send the data to
clientID	the string client identifier, only used for tracing

Returns: the completion code (e.g. TCPSOCKET_COMPLETE)

Definition at line 743 of file MQTTPacket.c.

int MQTTPacket_sends	(	networkHandles *	net,
		Header	header,
		PacketBuffers *	bufs,
		int	MQTTVersion
	)

Sends an MQTT packet from multiple buffers in one system call write

Parameters

socket	the socket to which to write the data
header	the one-byte MQTT header
count	the number of buffers
buffers	the rest of the buffers to write (not including remaining length)
buflens	the lengths of the data in the array of buffers to be written
the	MQTT version being used

Returns: the completion code (TCPSOCKET_COMPLETE etc)

Definition at line 250 of file MQTTPacket.c.

int MQTTPacket_VBIdecode	(	int()(char , int)	getcharfn,
		unsigned int *	value
	)

Decodes the message length according to the MQTT algorithm

Parameters

getcharfn	pointer to function to read the next character from the data source
value	the decoded length returned

Returns: the number of bytes read from the socket

Definition at line 1012 of file MQTTPacket.c.

int MQTTPacket_VBIlen ( int rem_len )

Definition at line 990 of file MQTTPacket.c.

unsigned char readChar ( 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

Definition at line 425 of file MQTTPacket.c.

int readInt ( char ** pptr )

Calculates an integer from two bytes read from the input buffer

Parameters

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

Returns: the integer value calculated

Definition at line 359 of file MQTTPacket.c.

int readInt4 ( char ** pptr )

Calculates an integer from two bytes read from the input buffer

Parameters

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

Returns: the integer value calculated

Definition at line 945 of file MQTTPacket.c.

char* readUTF	(	char **	pptr,
		char *	enddata
	)

Reads a "UTF" string from the input buffer. UTF as in the MQTT v3 spec which really means a length delimited string. So it reads the two byte length then the data according to that length. The end of the buffer is provided too, so we can prevent buffer overruns caused by an incorrect length.

Parameters

pptr	pointer to the input buffer - incremented by the number of bytes used & returned
enddata	pointer to the end of the buffer not to be read beyond

Returns: an allocated C string holding the characters read, or NULL if the length read would have caused an overrun.

Definition at line 413 of file MQTTPacket.c.

static char * readUTFlen	(	char **	pptr,
		char *	enddata,
		int *	len
	)

static

Reads a "UTF" string from the input buffer. UTF as in the MQTT v3 spec which really means a length delimited string. So it reads the two byte length then the data according to that length. The end of the buffer is provided too, so we can prevent buffer overruns caused by an incorrect length.

Parameters

pptr	pointer to the input buffer - incremented by the number of bytes used & returned
enddata	pointer to the end of the buffer not to be read beyond
len	returns the calculcated value of the length bytes read

Returns: an allocated C string holding the characters read, or NULL if the length read would have caused an overrun.

Definition at line 380 of file MQTTPacket.c.

void writeChar	(	char **	pptr,
		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

Definition at line 438 of file MQTTPacket.c.

void writeData	(	char **	pptr,
		const void *	data,
		int	datalen
	)

Writes length delimited data to an output buffer

Parameters

pptr	pointer to the output buffer - incremented by the number of bytes used & returned
data	the data to write
datalen	the length of the data to write

Definition at line 479 of file MQTTPacket.c.

void writeInt	(	char **	pptr,
		int	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

Definition at line 450 of file MQTTPacket.c.

void writeInt4	(	char **	pptr,
		int	anInt
	)

Writes an integer as 4 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

Definition at line 925 of file MQTTPacket.c.

void writeMQTTLenString	(	char **	pptr,
		MQTTLenString	lenstring
	)

Definition at line 954 of file MQTTPacket.c.

void writeUTF	(	char **	pptr,
		const char *	string
	)

Writes a "UTF" string to an output buffer. Converts C string to length-delimited.

Parameters

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

Definition at line 464 of file MQTTPacket.c.

Variable Documentation

char* bufptr

static

Definition at line 1040 of file MQTTPacket.c.

const char** MQTTClient_packet_names = packet_names

Definition at line 57 of file MQTTPacket.c.

pf new_packets[]

Initial value:

=
{
        NULL,   
        NULL,   
        MQTTPacket_connack, 
        MQTTPacket_publish,     
        MQTTPacket_ack, 
        MQTTPacket_ack, 
        MQTTPacket_ack, 
        MQTTPacket_ack, 
        NULL, 
        MQTTPacket_suback, 
        NULL, 
        MQTTPacket_unsuback, 
        MQTTPacket_header_only, 
        MQTTPacket_header_only, 
        MQTTPacket_ack,  
        MQTTPacket_ack   
}

Array of functions to build packets, indexed according to packet code

Definition at line 73 of file MQTTPacket.c.

const char* packet_names[]

static

Initial value:

=
{
        "RESERVED", "CONNECT", "CONNACK", "PUBLISH", "PUBACK", "PUBREC", "PUBREL",
        "PUBCOMP", "SUBSCRIBE", "SUBACK", "UNSUBSCRIBE", "UNSUBACK",
        "PINGREQ", "PINGRESP", "DISCONNECT", "AUTH"
}

List of the predefined MQTT v3/v5 packet names.

Definition at line 50 of file MQTTPacket.c.

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

Function Documentation

Variable Documentation