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core_mqtt_agent.c
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/*
* coreMQTT Agent v1.2.0
* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/**
* @file core_mqtt_agent.c
* @brief Implements an MQTT agent (or daemon task) to enable multithreaded access to
* coreMQTT.
*
* @note Implements an MQTT agent (or daemon task) on top of the coreMQTT MQTT client
* library. The agent makes coreMQTT usage thread safe by being the only task (or
* thread) in the system that is allowed to access the native coreMQTT API - and in
* so doing, serializes all access to coreMQTT even when multiple tasks are using the
* same MQTT connection.
*
* The agent provides an equivalent API for each coreMQTT API. Whereas coreMQTT
* APIs are prefixed "MQTT_", the agent APIs are prefixed "MQTTAgent_". For example,
* that agent's MQTTAgent_Publish() API is the thread safe equivalent to coreMQTT's
* MQTT_Publish() API.
*/
/* Standard includes. */
#include <string.h>
#include <stdio.h>
/* FreeRTOS includes. See the coreMQTT Agent, rather than FreeRTOS+MQTT, for
an OS agnostic version. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
/* MQTT agent include. */
#include "core_mqtt_agent.h"
#include "core_mqtt_agent_command_functions.h"
/* MQTT Agent default logging configuration include. */
#include "core_mqtt_agent_default_logging.h"
/*-----------------------------------------------------------*/
#if ( MQTT_AGENT_USE_QOS_1_2_PUBLISH != 0 )
/**
* @brief Array used to maintain the outgoing publish records and their
* state by the coreMQTT library.
*/
static MQTTPubAckInfo_t pOutgoingPublishRecords[ MQTT_AGENT_MAX_OUTSTANDING_ACKS ];
/**
* @brief Array used to maintain the incoming publish records and their
* state by the coreMQTT library.
*/
static MQTTPubAckInfo_t pIncomingPublishRecords[ MQTT_AGENT_MAX_OUTSTANDING_ACKS ];
#endif
/**
* @brief Track an operation by adding it to a list, indicating it is anticipating
* an acknowledgment.
*
* @param[in] pAgentContext Agent context for the MQTT connection.
* @param[in] packetId Packet ID of pending ack.
* @param[in] pCommand Pointer to command that is expecting an ack.
*
* @return Returns one of the following:
* - #MQTTSuccess if an entry was added for the to the list.
* - #MQTTStateCollision if there already exists an entry for the same packet ID
* in the list.
* - #MQTTNoMemory if there is no space available in the list for adding a
* new entry.
*/
static MQTTStatus_t addAwaitingOperation( MQTTAgentContext_t * pAgentContext,
uint16_t packetId,
MQTTAgentCommand_t * pCommand );
/**
* @brief Retrieve an operation from the list of pending acks, and optionally
* remove it from the list.
*
* @param[in] pAgentContext Agent context for the MQTT connection.
* @param[in] incomingPacketId Packet ID of incoming ack.
*
* @return Pointer to stored information about the operation awaiting the ack.
* Returns NULL if the packet ID is zero or original command does not exist.
*/
static MQTTAgentAckInfo_t * getAwaitingOperation( MQTTAgentContext_t * pAgentContext,
uint16_t incomingPacketId );
/**
* @brief Populate the parameters of a #MQTTAgentCommand struct.
*
* @param[in] commandType Type of command. For example, publish or subscribe.
* @param[in] pMqttAgentContext Pointer to MQTT context to use for command.
* @param[in] pMqttInfoParam Pointer to MQTTPublishInfo_t or MQTTSubscribeInfo_t.
* @param[in] commandCompleteCallback Callback for when command completes.
* @param[in] pCommandCompleteCallbackContext Context and necessary structs for command.
* @param[out] pCommand Pointer to initialized command.
*
* @return #MQTTSuccess if all necessary fields for the command are passed,
* else an enumerated error code.
*/
static MQTTStatus_t createCommand( MQTTAgentCommandType_t commandType,
const MQTTAgentContext_t * pMqttAgentContext,
void * pMqttInfoParam,
MQTTAgentCommandCallback_t commandCompleteCallback,
MQTTAgentCommandContext_t * pCommandCompleteCallbackContext,
MQTTAgentCommand_t * pCommand );
/**
* @brief Add a command to the global command queue.
*
* @param[in] pAgentContext Agent context for the MQTT connection.
* @param[in] pCommand Pointer to command to copy to queue.
* @param[in] blockTimeMs The maximum amount of time to milliseconds to wait in the
* Blocked state (so not consuming any CPU time) for the command to be posted to the
* queue should the queue already be full.
*
* @return #MQTTSuccess if the command was added to the queue, else an enumerated
* error code.
*/
static MQTTStatus_t addCommandToQueue( const MQTTAgentContext_t * pAgentContext,
MQTTAgentCommand_t * pCommand,
uint32_t blockTimeMs );
/**
* @brief Process a #MQTTAgentCommand struct.
*
* @note This agent does not check existing subscriptions before sending a
* SUBSCRIBE or UNSUBSCRIBE packet. If a subscription already exists, then
* a SUBSCRIBE packet will be sent anyway, and if multiple tasks are subscribed
* to a topic filter, then they will all be unsubscribed after an UNSUBSCRIBE.
*
* @param[in] pMqttAgentContext Agent context for MQTT connection.
* @param[in] pCommand Pointer to command to process.
* @param[out] pEndLoop Whether the command loop should terminate.
*
* @return status of MQTT library API call.
*/
static MQTTStatus_t processCommand( MQTTAgentContext_t * pMqttAgentContext,
MQTTAgentCommand_t * pCommand,
bool * pEndLoop );
/**
* @brief Dispatch incoming publishes and acks to their various handler functions.
*
* @param[in] pMqttContext MQTT Context
* @param[in] pPacketInfo Pointer to incoming packet.
* @param[in] pDeserializedInfo Pointer to deserialized information from
* the incoming packet.
*/
static void mqttEventCallback( MQTTContext_t * pMqttContext,
MQTTPacketInfo_t * pPacketInfo,
MQTTDeserializedInfo_t * pDeserializedInfo );
/**
* @brief Mark a command as complete after receiving an acknowledgment packet.
*
* @param[in] pAgentContext Agent context for the MQTT connection.
* @param[in] pPacketInfo Pointer to incoming packet.
* @param[in] pDeserializedInfo Pointer to deserialized information from
* the incoming packet.
* @param[in] pAckInfo Pointer to stored information for the original operation
* resulting in the received packet.
* @param[in] packetType The type of the incoming packet, either SUBACK, UNSUBACK,
* PUBACK, or PUBCOMP.
*/
static void handleAcks( const MQTTAgentContext_t * pAgentContext,
const MQTTPacketInfo_t * pPacketInfo,
const MQTTDeserializedInfo_t * pDeserializedInfo,
MQTTAgentAckInfo_t * pAckInfo,
uint8_t packetType );
/**
* @brief Retrieve a pointer to an agent context given an MQTT context.
*
* @param[in] pMQTTContext MQTT Context to search for.
*
* @return Pointer to agent context, or NULL.
*/
static MQTTAgentContext_t * getAgentFromMQTTContext( MQTTContext_t * pMQTTContext );
/**
* @brief Helper function for creating a command and adding it to the command
* queue.
*
* @param[in] commandType Type of command.
* @param[in] pMqttAgentContext Handle of the MQTT connection to use.
* @param[in] pCommandCompleteCallbackContext Context and necessary structs for command.
* @param[in] commandCompleteCallback Callback for when command completes.
* @param[in] pMqttInfoParam Pointer to command argument.
* @param[in] blockTimeMs Maximum amount of time in milliseconds to wait (in the
* Blocked state, so not consuming any CPU time) for the command to be posted to the
* MQTT agent should the MQTT agent's event queue be full.
*
* @return #MQTTSuccess if the command was posted to the MQTT agent's event queue.
* Otherwise an enumerated error code.
*/
static MQTTStatus_t createAndAddCommand( MQTTAgentCommandType_t commandType,
const MQTTAgentContext_t * pMqttAgentContext,
void * pMqttInfoParam,
MQTTAgentCommandCallback_t commandCompleteCallback,
MQTTAgentCommandContext_t * pCommandCompleteCallbackContext,
uint32_t blockTimeMs );
/**
* @brief Helper function to mark a command as complete and invoke its callback.
* This function calls the releaseCommand callback.
*
* @param[in] pCommand Command to complete.
* @param[in] returnCode Return status of command.
* @param[in] pSubackCodes Pointer to suback array, if command is a SUBSCRIBE.
*/
static void concludeCommand( MQTTAgentCommand_t * pCommand,
MQTTStatus_t returnCode,
uint8_t * pSubackCodes );
/**
* @brief Resend QoS 1 and 2 publishes after resuming a session.
*
* @param[in] pMqttAgentContext Agent context for the MQTT connection.
*
* @return #MQTTSuccess if all publishes resent successfully, else error code
* from #MQTT_Publish.
*/
static MQTTStatus_t resendPublishes( MQTTAgentContext_t * pMqttAgentContext );
/**
* @brief Clears the list of pending acknowledgments by invoking each callback
* with #MQTTRecvFailed either for ALL operations in the list OR only for
* Subscribe/Unsubscribe operations.
*
* @param[in] pMqttAgentContext Agent context of the MQTT connection.
* @param[in] clearOnlySubUnsubEntries Flag indicating whether all entries OR
* entries pertaining to only Subscribe/Unsubscribe operations should be cleaned
* from the list.
*/
static void clearPendingAcknowledgments( MQTTAgentContext_t * pMqttAgentContext,
bool clearOnlySubUnsubEntries );
/**
* @brief Validate an #MQTTAgentContext_t and a #MQTTAgentCommandInfo_t from API
* functions.
*
* @param[in] pMqttAgentContext #MQTTAgentContext_t to validate.
* @param[in] pCommandInfo #MQTTAgentCommandInfo_t to validate.
*
* @return `true` if parameters are valid, else `false`.
*/
static bool validateStruct( const MQTTAgentContext_t * pMqttAgentContext,
const MQTTAgentCommandInfo_t * pCommandInfo );
/**
* @brief Validate the parameters for a CONNECT, SUBSCRIBE, UNSUBSCRIBE
* or PUBLISH.
*
* @param[in] commandType CONNECT, SUBSCRIBE, UNSUBSCRIBE, or PUBLISH.
* @param[in] pParams Parameter structure to validate.
*
* @return `true` if parameter structure is valid, else `false`.
*/
static bool validateParams( MQTTAgentCommandType_t commandType,
const void * pParams );
/**
* @brief Called before accepting any PUBLISH or SUBSCRIBE messages to check
* there is space in the pending ACK list for the outgoing PUBLISH or SUBSCRIBE.
*
* @note Because the MQTT agent is inherently multi threaded, and this function
* is called from the context of the application task and not the MQTT agent
* task, this function can only return a best effort result. It can definitely
* say if there is space for a new pending ACK when the function is called, but
* the case of space being exhausted when the agent executes a command that
* results in an ACK must still be handled.
*
* @param[in] pAgentContext Pointer to the context for the MQTT connection to
* which the PUBLISH or SUBSCRIBE message is to be sent.
*
* @return true if there is space in that MQTT connection's ACK list, otherwise
* false;
*/
static bool isSpaceInPendingAckList( const MQTTAgentContext_t * pAgentContext );
/*_RB_ TBD comments. */
static MQTTStatus_t prvWaitAckIfSynchronous( MQTTStatus_t statusReturn,
BaseType_t xSynchronous,
uint32_t ulCommandNumber,
TickType_t xTimeToWait_ms );
static void prvInitialiseCommandStructurePool( void );
static MQTTAgentCommand_t * prvGetCommandStructure( uint32_t blockTimeMs );
static bool prvReturnCommandStructure( MQTTAgentCommand_t * pCommandToRelease );
/*-----------------------------------------------------------*/
struct SyncCommandContext
{
TaskHandle_t xTaskToNotify;
uint32_t ulCommandNumber;
};
typedef struct SyncCommandContext SyncCommandContext_t;
///////////////////////////////////////////////////_RB_
/**
* @brief The pool of command structures used to hold information on commands (such
* as PUBLISH or SUBSCRIBE) between the command being created by an API call and
* completion of the command by the execution of the command's callback.
*/
static MQTTAgentCommand_t commandStructurePool[ MQTT_COMMAND_CONTEXTS_POOL_SIZE ];
/**
* @brief Command structures may be obtained by receiving a pointer from the
* queue, and returned by sending the pointer back into the queue.
*/
static QueueHandle_t xCommandQueue = NULL;
/*-----------------------------------------------------------*/
static void prvInitialiseCommandStructurePool( void )
{
size_t i;
MQTTAgentCommand_t * pCommand;
static uint8_t staticQueueStorageArea[ MQTT_COMMAND_CONTEXTS_POOL_SIZE * sizeof( MQTTAgentCommand_t * ) ];
static StaticQueue_t staticQueueStructure;
if( xCommandQueue == NULL )
{
memset( ( void * ) commandStructurePool, 0x00, sizeof( commandStructurePool ) );
xCommandQueue = xQueueCreateStatic( MQTT_COMMAND_CONTEXTS_POOL_SIZE, sizeof( MQTTAgentCommand_t * ), staticQueueStorageArea, &staticQueueStructure );
/* Populate the queue. */
for( i = 0; i < MQTT_COMMAND_CONTEXTS_POOL_SIZE; i++ )
{
/* Store the address as a variable. */
pCommand = &commandStructurePool[ i ];
/* Send the pointer to the queue. Should never fail as the
loop counter and queue size use the same constant. */
xQueueSend( xCommandQueue, &pCommand, pdMS_TO_TICKS( 0 ) ); /*_RB_ The queue is the only member of the structure. */
}
}
}
/*-----------------------------------------------------------*/
static MQTTAgentCommand_t * prvGetCommandStructure( uint32_t blockTimeMs )
{
MQTTAgentCommand_t * structToUse = NULL;
BaseType_t structRetrieved = false;
/* Check queue has been created. */
configASSERT( xCommandQueue != NULL );
/* Retrieve a struct from the queue. */
structRetrieved = xQueueReceive( xCommandQueue, &( structToUse ), blockTimeMs );
if( structRetrieved != pdPASS )
{
LogError( ( "No command structure available." ) );
}
return structToUse;
}
/*-----------------------------------------------------------*/
static bool prvReturnCommandStructure( MQTTAgentCommand_t * pCommandToRelease )
{
bool structReturned = false;
configASSERT( xCommandQueue != NULL );
/* See if the structure being returned is actually from the pool. */
if( ( pCommandToRelease >= commandStructurePool ) &&
( pCommandToRelease < ( commandStructurePool + MQTT_COMMAND_CONTEXTS_POOL_SIZE ) ) )
{
/* A block time of zero is ok here because there are as many structures
* as there are spaces in the queue. *//*_RB_Note about writing useful comments. */
structReturned = xQueueSend( xCommandQueue, &pCommandToRelease , 0U );
/* The send should not fail as the queue was created to hold every command
* in the pool. */
configASSERT( structReturned );
LogDebug( ( "Returned Command Context %d to pool",
( int ) ( pCommandToRelease - commandStructurePool ) ) );
}
return structReturned;
}
///////////////////////////////////////////////////_RB_
/*-----------------------------------------------------------*/
static bool isSpaceInPendingAckList( const MQTTAgentContext_t * pAgentContext )
{
const MQTTAgentAckInfo_t * pendingAcks;
bool spaceFound = false;
size_t i;
configASSERT( pAgentContext != NULL );
pendingAcks = pAgentContext->pPendingAcks;
/* Are there any open slots? */
for( i = 0; i < MQTT_AGENT_MAX_OUTSTANDING_ACKS; i++ )
{
/* If the packetId is MQTT_PACKET_ID_INVALID then the array space is
* not in use. */
if( pendingAcks[ i ].packetId == MQTT_PACKET_ID_INVALID )
{
spaceFound = true;
break;
}
}
return spaceFound;
}
/*-----------------------------------------------------------*/
static MQTTStatus_t addAwaitingOperation( MQTTAgentContext_t * pAgentContext,
uint16_t packetId,
MQTTAgentCommand_t * pCommand )
{
size_t i = 0, unusedPos = MQTT_AGENT_MAX_OUTSTANDING_ACKS;
MQTTStatus_t status = MQTTNoMemory;
MQTTAgentAckInfo_t * pendingAcks = NULL;
configASSERT( pAgentContext != NULL );
configASSERT( pCommand != NULL );
configASSERT( packetId != MQTT_PACKET_ID_INVALID );
pendingAcks = pAgentContext->pPendingAcks;
/* Before adding the record for the pending acknowledgement of the packet ID,
* make sure that there doesn't already exist an entry for the same packet ID.
* Also, as part of iterating through the list of pending acknowledgements,
* find an unused space for the packet ID to be added, if it can be. */
for( i = 0; i < MQTT_AGENT_MAX_OUTSTANDING_ACKS; i++ )
{
/* If the packetId is MQTT_PACKET_ID_INVALID then the array space is not in
* use. */
if( ( unusedPos == MQTT_AGENT_MAX_OUTSTANDING_ACKS ) &&
( pendingAcks[ i ].packetId == MQTT_PACKET_ID_INVALID ) )
{
unusedPos = i;
status = MQTTSuccess;
}
if( pendingAcks[ i ].packetId == packetId )
{
/* Check whether there exists a duplicate entry for pending
* acknowledgment for the same packet ID that we want to add to
* the list.
* Note: This is an unlikely edge case which represents that a packet ID
* didn't receive acknowledgment, but subsequent SUBSCRIBE/PUBLISH operations
* representing 65535 packet IDs were successful that caused the bit packet
* ID value to wrap around and reached the same packet ID as that was still
* pending acknowledgment.
*/
status = MQTTStateCollision;
LogError( ( "Failed to add operation to list of pending acknowledgments: "
"Existing entry found for same packet: PacketId=%u\n", packetId ) );
break;
}
}
/* Add the packet ID to the list if there is space available, and there is no
* duplicate entry for the same packet ID found. */
if( status == MQTTSuccess )
{
pendingAcks[ unusedPos ].packetId = packetId;
pendingAcks[ unusedPos ].pOriginalCommand = pCommand;
}
else if( status == MQTTNoMemory )
{
LogError( ( "Failed to add operation to list of pending acknowledgments: "
"No memory available: PacketId=%u\n", packetId ) );
}
else
{
/* Empty else MISRA 15.7 */
}
return status;
}
/*-----------------------------------------------------------*/
static MQTTAgentAckInfo_t * getAwaitingOperation( MQTTAgentContext_t * pAgentContext,
uint16_t incomingPacketId )
{
size_t i = 0;
MQTTAgentAckInfo_t * pFoundAck = NULL;
configASSERT( pAgentContext != NULL );
/* Look through the array of packet IDs that are still waiting to be acked to
* find one with incomingPacketId. */
for( i = 0; i < MQTT_AGENT_MAX_OUTSTANDING_ACKS; i++ )
{
if( pAgentContext->pPendingAcks[ i ].packetId == incomingPacketId )
{
pFoundAck = &( pAgentContext->pPendingAcks[ i ] );
break;
}
}
if( pFoundAck == NULL )
{
LogError( ( "No ack found for packet id %u.\n", incomingPacketId ) );
}
else if( ( pFoundAck->pOriginalCommand == NULL ) || ( pFoundAck->packetId == 0U ) )
{
LogError( ( "Found ack had empty fields. PacketId=%hu, Original Command=%p",
( unsigned short ) pFoundAck->packetId,
( void * ) pFoundAck->pOriginalCommand ) );
( void ) memset( pFoundAck, 0x00, sizeof( MQTTAgentAckInfo_t ) );
pFoundAck = NULL;
}
else
{
/* Empty else MISRA 15.7 */
}
return pFoundAck;
}
/*-----------------------------------------------------------*/
static MQTTStatus_t createCommand( MQTTAgentCommandType_t commandType,
const MQTTAgentContext_t * pMqttAgentContext,
void * pMqttInfoParam,
MQTTAgentCommandCallback_t commandCompleteCallback,
MQTTAgentCommandContext_t * pCommandCompleteCallbackContext,
MQTTAgentCommand_t * pCommand )
{
bool isValid, isSpace = true;
MQTTStatus_t statusReturn;
const MQTTPublishInfo_t * pPublishInfo;
size_t uxHeaderBytes;
const size_t uxControlAndLengthBytes = ( size_t ) 4; /* Control, remaining length and length bytes. */
configASSERT( pMqttAgentContext != NULL );
configASSERT( pCommand != NULL );
( void ) memset( pCommand, 0x00, sizeof( MQTTAgentCommand_t ) );
/* Determine if required parameters are present in context. */
switch( commandType )
{
case SUBSCRIBE:
case UNSUBSCRIBE:
configASSERT( pMqttInfoParam != NULL );
/* This message type results in the broker returning an ACK. The
* agent maintains an array of outstanding ACK messages. See if
* the array contains space for another outstanding ack. */
isSpace = isSpaceInPendingAckList( pMqttAgentContext );
isValid = isSpace;
break;
case PUBLISH:
pPublishInfo = ( const MQTTPublishInfo_t * ) pMqttInfoParam;
/* Calculate the space consumed by everything other than the
* payload. */
uxHeaderBytes = uxControlAndLengthBytes;
uxHeaderBytes += pPublishInfo->topicNameLength;
/* This message type results in the broker returning an ACK. The
* agent maintains an array of outstanding ACK messages. See if
* the array contains space for another outstanding ack. QoS0
* publish does not result in an ack so it doesn't matter if
* there is no space in the ACK array. */
if( pPublishInfo->qos != MQTTQoS0 )
{
isSpace = isSpaceInPendingAckList( pMqttAgentContext );
}
/* Will the message fit in the defined buffer? */
isValid = ( uxHeaderBytes < pMqttAgentContext->mqttContext.networkBuffer.size ) &&
( isSpace == true );
break;
case PROCESSLOOP:
case PING:
case CONNECT:
case DISCONNECT:
default:
/* Other operations don't need to store ACKs. */
isValid = true;
break;
}
if( isValid )
{
pCommand->commandType = commandType;
pCommand->pArgs = pMqttInfoParam;
pCommand->pCmdContext = pCommandCompleteCallbackContext;
pCommand->pCommandCompleteCallback = commandCompleteCallback;
}
statusReturn = ( isValid ) ? MQTTSuccess : MQTTBadParameter;
if( ( statusReturn == MQTTBadParameter ) && ( isSpace == false ) )
{
/* The error was caused not by a bad parameter, but because there was
* no room in the pending Ack list for the Ack response to an outgoing
* PUBLISH or SUBSCRIBE message. */
statusReturn = MQTTNoMemory;
}
return statusReturn;
}
/*-----------------------------------------------------------*/
static MQTTStatus_t addCommandToQueue( const MQTTAgentContext_t * pAgentContext,
MQTTAgentCommand_t * pCommand,
uint32_t blockTimeMs )
{
BaseType_t queueStatus;
MQTTStatus_t mqttStatus = MQTTSuccess;
configASSERT( pAgentContext != NULL );
configASSERT( pCommand != NULL );
/* The application called an API function. The API function was validated and
* packed into a MQTTAgentCommand_t structure. Now post a reference to the MQTTAgentCommand_t
* structure to the MQTT agent for processing. */
queueStatus = xQueueSend( pAgentContext->commandQueue, &pCommand, pdMS_TO_TICKS( blockTimeMs ) );
if( queueStatus != pdPASS )
{
mqttStatus = MQTTSendFailed;
}
return mqttStatus;
}
/*-----------------------------------------------------------*/
static MQTTStatus_t processCommand( MQTTAgentContext_t * pMqttAgentContext,
MQTTAgentCommand_t * pCommand,
bool * pEndLoop )
{
const MQTTAgentCommandFunc_t pCommandFunctionTable[ NUM_COMMANDS ] = MQTT_AGENT_FUNCTION_TABLE;
MQTTStatus_t operationStatus = MQTTSuccess;
bool ackAdded = false;
MQTTAgentCommandFunc_t commandFunction = NULL;
void * pCommandArgs = NULL;
MQTTAgentCommandFuncReturns_t commandOutParams = { 0 };
configASSERT( pMqttAgentContext != NULL );
configASSERT( pEndLoop != NULL );
if( pCommand != NULL )
{
configASSERT( pCommand->commandType < NUM_COMMANDS );
if( ( pCommand->commandType >= NONE ) && ( pCommand->commandType < NUM_COMMANDS ) )
{
commandFunction = pCommandFunctionTable[ pCommand->commandType ];
pCommandArgs = pCommand->pArgs;
}
else
{
LogWarn( ( "An incorrect command type was received by the processCommand function."
" Type = %d.", pCommand->commandType ) );
commandFunction = pCommandFunctionTable[ NONE ];
}
}
else
{
commandFunction = pCommandFunctionTable[ NONE ];
}
operationStatus = commandFunction( pMqttAgentContext, pCommandArgs, &commandOutParams );
if( ( operationStatus == MQTTSuccess ) &&
( commandOutParams.addAcknowledgment != false ) &&
( commandOutParams.packetId != MQTT_PACKET_ID_INVALID ) )
{
/*_RB_ Needs a comment or a different function name - I think this is registering a pending ACK. */
operationStatus = addAwaitingOperation( pMqttAgentContext, commandOutParams.packetId, pCommand );
ackAdded = ( operationStatus == MQTTSuccess );
}
if( ( pCommand != NULL ) && ( ackAdded != true ) )
{
/* The command is complete, call the callback. */
concludeCommand( pCommand, operationStatus, NULL );
}
/* Run the process loop if there were no errors and the MQTT connection
* still exists. */
if( ( operationStatus == MQTTSuccess ) && commandOutParams.runProcessLoop )
{
do
{
pMqttAgentContext->packetReceivedInLoop = false;
if( ( operationStatus == MQTTSuccess ) && ( pMqttAgentContext->mqttContext.connectStatus == MQTTConnected ) )
{
operationStatus = MQTT_ProcessLoop( &( pMqttAgentContext->mqttContext ) );
}
} while( pMqttAgentContext->packetReceivedInLoop );
}
/* Set the flag to break from the command loop. */
if( ( operationStatus != MQTTSuccess ) && ( operationStatus != MQTTNeedMoreBytes ) )
{
*pEndLoop = true;
}
else
{
*pEndLoop = commandOutParams.endLoop;
}
return operationStatus;
}
/*-----------------------------------------------------------*/
static void handleAcks( const MQTTAgentContext_t * pAgentContext,
const MQTTPacketInfo_t * pPacketInfo,
const MQTTDeserializedInfo_t * pDeserializedInfo,
MQTTAgentAckInfo_t * pAckInfo,
uint8_t packetType )
{
uint8_t * pSubackCodes = NULL;
configASSERT( pAckInfo != NULL );
configASSERT( pAckInfo->pOriginalCommand != NULL );
/* A SUBACK's status codes start 2 bytes after the variable header. */
pSubackCodes = ( packetType == MQTT_PACKET_TYPE_SUBACK ) ? ( pPacketInfo->pRemainingData + 2U ) : NULL;
concludeCommand( pAckInfo->pOriginalCommand,
pDeserializedInfo->deserializationResult,
pSubackCodes );
/* Clear the entry from the list. */
( void ) memset( pAckInfo, 0x00, sizeof( MQTTAgentAckInfo_t ) );
}
/*-----------------------------------------------------------*/
static MQTTAgentContext_t * getAgentFromMQTTContext( MQTTContext_t * pMQTTContext )
{
MQTTAgentContext_t ctx = { 0 };
ptrdiff_t offset = ( ( uint8_t * ) &( ctx.mqttContext ) ) - ( ( uint8_t * ) &ctx );
return ( MQTTAgentContext_t * ) &( ( ( uint8_t * ) pMQTTContext )[ 0 - offset ] );
}
/*-----------------------------------------------------------*/
static void mqttEventCallback( MQTTContext_t * pMqttContext,
MQTTPacketInfo_t * pPacketInfo,
MQTTDeserializedInfo_t * pDeserializedInfo )
{
MQTTAgentAckInfo_t * pAckInfo;
uint16_t packetIdentifier = pDeserializedInfo->packetIdentifier;
MQTTAgentContext_t * pAgentContext;
const uint8_t upperNibble = ( uint8_t ) 0xF0;
configASSERT( pMqttContext != NULL );
configASSERT( pPacketInfo != NULL );
pAgentContext = getAgentFromMQTTContext( pMqttContext );
/* This callback executes from within MQTT_ProcessLoop(). Setting this flag
* indicates that the callback executed so the caller of MQTT_ProcessLoop() knows
* it should call it again as there may be more data to process. */
pAgentContext->packetReceivedInLoop = true;
/* Handle incoming publish. The lower 4 bits of the publish packet type is used
* for the dup, QoS, and retain flags. Hence masking out the lower bits to check
* if the packet is publish. */
if( ( pPacketInfo->type & upperNibble ) == MQTT_PACKET_TYPE_PUBLISH )
{
pAgentContext->pIncomingCallback( pAgentContext, packetIdentifier, pDeserializedInfo->pPublishInfo );
}
else
{
/* Handle other packets. */
switch( pPacketInfo->type )
{
case MQTT_PACKET_TYPE_PUBACK:
case MQTT_PACKET_TYPE_PUBCOMP:
case MQTT_PACKET_TYPE_SUBACK:
case MQTT_PACKET_TYPE_UNSUBACK:
pAckInfo = getAwaitingOperation( pAgentContext, packetIdentifier );
if( pAckInfo != NULL )
{
/* This function will also clear the memory associated with
* the ack list entry. */
handleAcks( pAgentContext,
pPacketInfo,
pDeserializedInfo,
pAckInfo,
pPacketInfo->type );
}
else
{
LogError( ( "No operation found matching packet id %u.\n", packetIdentifier ) );
}
break;
/* Nothing to do for these packets since they don't indicate command completion. */
case MQTT_PACKET_TYPE_PUBREC:
case MQTT_PACKET_TYPE_PUBREL:
break;
/* Any other packet type is invalid. */
case MQTT_PACKET_TYPE_PINGRESP:
default:
LogError( ( "Unknown packet type received:(%02x).\n",
pPacketInfo->type ) );
break;
}
}
}
/*-----------------------------------------------------------*/
static MQTTStatus_t createAndAddCommand( MQTTAgentCommandType_t commandType,
const MQTTAgentContext_t * pMqttAgentContext,
void * pMqttInfoParam,
MQTTAgentCommandCallback_t commandCompleteCallback,
MQTTAgentCommandContext_t * pCommandCompleteCallbackContext,
uint32_t blockTimeMs )
{
MQTTStatus_t statusReturn = MQTTBadParameter;
MQTTAgentCommand_t * pCommand;
bool commandReleased = false;
/* If the packet ID is zero then the MQTT context has not been initialized as 0
* is the initial value but not a valid packet ID. */
if( pMqttAgentContext->mqttContext.nextPacketId != MQTT_PACKET_ID_INVALID )
{
pCommand = prvGetCommandStructure( blockTimeMs );
if( pCommand != NULL )
{
statusReturn = createCommand( commandType,
pMqttAgentContext,
pMqttInfoParam,
commandCompleteCallback,
pCommandCompleteCallbackContext,
pCommand );
if( statusReturn == MQTTSuccess )
{
statusReturn = addCommandToQueue( pMqttAgentContext, pCommand, blockTimeMs );
}
if( statusReturn != MQTTSuccess )
{
/* Could not send the command to the queue so release the command
* structure again. */
commandReleased = prvReturnCommandStructure( pCommand );
if( !commandReleased )
{
LogError( ( "Command %p could not be released.",
( void * ) pCommand ) );
}
}
}
else
{
/* Ran out of MQTTAgentCommand_t structures - pool is empty. */
statusReturn = MQTTNoMemory;
}
}
else
{
LogError( ( "MQTT context must be initialized." ) );
}
return statusReturn;
}
/*-----------------------------------------------------------*/
static void concludeCommand( MQTTAgentCommand_t * pCommand,
MQTTStatus_t returnCode,
uint8_t * pSubackCodes )
{
bool commandReleased = false;
MQTTAgentReturnInfo_t returnInfo;
( void ) memset( &returnInfo, 0x00, sizeof( MQTTAgentReturnInfo_t ) );
configASSERT( pCommand != NULL );
returnInfo.returnCode = returnCode;
returnInfo.pSubackCodes = pSubackCodes;
if( pCommand->pCommandCompleteCallback != NULL )
{
pCommand->pCommandCompleteCallback( pCommand->pCmdContext, &returnInfo );
}
commandReleased = prvReturnCommandStructure( pCommand );
if( !commandReleased )
{
LogError( ( "Failed to release command %p of type %d.",
( void * ) pCommand,
pCommand->commandType ) );
}
}
/*-----------------------------------------------------------*/
static MQTTStatus_t resendPublishes( MQTTAgentContext_t * pMqttAgentContext )
{
MQTTStatus_t statusResult = MQTTSuccess;
MQTTStateCursor_t cursor = MQTT_STATE_CURSOR_INITIALIZER;
uint16_t packetId = MQTT_PACKET_ID_INVALID;
MQTTAgentAckInfo_t * pFoundAck = NULL;
MQTTPublishInfo_t * pOriginalPublish = NULL;
MQTTContext_t * pMqttContext;
configASSERT( pMqttAgentContext != NULL );
pMqttContext = &( pMqttAgentContext->mqttContext );
packetId = MQTT_PublishToResend( pMqttContext, &cursor );
while( packetId != MQTT_PACKET_ID_INVALID )
{
/* Retrieve the operation but do not remove it from the list. */
pFoundAck = getAwaitingOperation( pMqttAgentContext, packetId );
if( pFoundAck != NULL )
{
/* Set the DUP flag. */
pOriginalPublish = ( MQTTPublishInfo_t * ) ( pFoundAck->pOriginalCommand->pArgs );
pOriginalPublish->dup = true;
statusResult = MQTT_Publish( pMqttContext, pOriginalPublish, packetId );
if( statusResult != MQTTSuccess )
{
concludeCommand( pFoundAck->pOriginalCommand, statusResult, NULL );
( void ) memset( pFoundAck, 0x00, sizeof( MQTTAgentAckInfo_t ) );
LogError( ( "Failed to resend publishes. Error code=%s\n", MQTT_Status_strerror( statusResult ) ) );
break;
}
}
packetId = MQTT_PublishToResend( pMqttContext, &cursor );
}
return statusResult;
}
/*-----------------------------------------------------------*/
static void clearPendingAcknowledgments( MQTTAgentContext_t * pMqttAgentContext,
bool clearOnlySubUnsubEntries )
{
size_t i = 0;
MQTTAgentAckInfo_t * pendingAcks;