/* * coreMQTT v1.0.1 * Copyright (C) 2020 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.c * @brief Implements the user-facing functions in core_mqtt.h. */ #include #include #include "core_mqtt.h" #include "core_mqtt_state.h" /*-----------------------------------------------------------*/ /** * @brief Sends provided buffer to network using transport send. * * @brief param[in] pContext Initialized MQTT context. * @brief param[in] pBufferToSend Buffer to be sent to network. * @brief param[in] bytesToSend Number of bytes to be sent. * * @return Total number of bytes sent, or negative number on network error. */ static int32_t sendPacket( MQTTContext_t * pContext, const uint8_t * pBufferToSend, size_t bytesToSend ); /** * @brief Calculate the interval between two millisecond timestamps, including * when the later value has overflowed. * * @note In C, the operands are promoted to signed integers in subtraction. * Using this function avoids the need to cast the result of subtractions back * to uint32_t. * * @param[in] later The later time stamp, in milliseconds. * @param[in] start The earlier time stamp, in milliseconds. * * @return later - start. */ static uint32_t calculateElapsedTime( uint32_t later, uint32_t start ); /** * @brief Convert a byte indicating a publish ack type to an #MQTTPubAckType_t. * * @param[in] packetType First byte of fixed header. * * @return Type of ack. */ static MQTTPubAckType_t getAckFromPacketType( uint8_t packetType ); /** * @brief Receive bytes into the network buffer, with a timeout. * * @param[in] pContext Initialized MQTT Context. * @param[in] bytesToRecv Number of bytes to receive. * @param[in] timeoutMs Time remaining to receive the packet. * * @return Number of bytes received, or negative number on network error. */ static int32_t recvExact( const MQTTContext_t * pContext, size_t bytesToRecv, uint32_t timeoutMs ); /** * @brief Discard a packet from the transport interface. * * @param[in] pContext MQTT Connection context. * @param[in] remainingLength Remaining length of the packet to dump. * @param[in] timeoutMs Time remaining to discard the packet. * * @return #MQTTRecvFailed or #MQTTNoDataAvailable. */ static MQTTStatus_t discardPacket( const MQTTContext_t * pContext, size_t remainingLength, uint32_t timeoutMs ); /** * @brief Receive a packet from the transport interface. * * @param[in] pContext MQTT Connection context. * @param[in] incomingPacket packet struct with remaining length. * @param[in] remainingTimeMs Time remaining to receive the packet. * * @return #MQTTSuccess or #MQTTRecvFailed. */ static MQTTStatus_t receivePacket( const MQTTContext_t * pContext, MQTTPacketInfo_t incomingPacket, uint32_t remainingTimeMs ); /** * @brief Get the correct ack type to send. * * @param[in] state Current state of publish. * * @return Packet Type byte of PUBACK, PUBREC, PUBREL, or PUBCOMP if one of * those should be sent, else 0. */ static uint8_t getAckTypeToSend( MQTTPublishState_t state ); /** * @brief Send acks for received QoS 1/2 publishes. * * @param[in] pContext MQTT Connection context. * @param[in] packetId packet ID of original PUBLISH. * @param[in] publishState Current publish state in record. * * @return #MQTTSuccess, #MQTTIllegalState or #MQTTSendFailed. */ static MQTTStatus_t sendPublishAcks( MQTTContext_t * pContext, uint16_t packetId, MQTTPublishState_t publishState ); /** * @brief Send a keep alive PINGREQ if the keep alive interval has elapsed. * * @param[in] pContext Initialized MQTT Context. * * @return #MQTTKeepAliveTimeout if a PINGRESP is not received in time, * #MQTTSendFailed if the PINGREQ cannot be sent, or #MQTTSuccess. */ static MQTTStatus_t handleKeepAlive( MQTTContext_t * pContext ); /** * @brief Handle received MQTT PUBLISH packet. * * @param[in] pContext MQTT Connection context. * @param[in] pIncomingPacket Incoming packet. * * @return MQTTSuccess, MQTTIllegalState or deserialization error. */ static MQTTStatus_t handleIncomingPublish( MQTTContext_t * pContext, MQTTPacketInfo_t * pIncomingPacket ); /** * @brief Handle received MQTT publish acks. * * @param[in] pContext MQTT Connection context. * @param[in] pIncomingPacket Incoming packet. * * @return MQTTSuccess, MQTTIllegalState, or deserialization error. */ static MQTTStatus_t handlePublishAcks( MQTTContext_t * pContext, MQTTPacketInfo_t * pIncomingPacket ); /** * @brief Handle received MQTT ack. * * @param[in] pContext MQTT Connection context. * @param[in] pIncomingPacket Incoming packet. * @param[in] manageKeepAlive Flag indicating if PINGRESPs should not be given * to the application * * @return MQTTSuccess, MQTTIllegalState, or deserialization error. */ static MQTTStatus_t handleIncomingAck( MQTTContext_t * pContext, MQTTPacketInfo_t * pIncomingPacket, bool manageKeepAlive ); /** * @brief Run a single iteration of the receive loop. * * @param[in] pContext MQTT Connection context. * @param[in] remainingTimeMs Remaining time for the loop in milliseconds. * @param[in] manageKeepAlive Flag indicating if keep alive should be handled. * * @return #MQTTRecvFailed if a network error occurs during reception; * #MQTTSendFailed if a network error occurs while sending an ACK or PINGREQ; * #MQTTBadResponse if an invalid packet is received; * #MQTTKeepAliveTimeout if the server has not sent a PINGRESP before * #MQTT_PINGRESP_TIMEOUT_MS milliseconds; * #MQTTIllegalState if an incoming QoS 1/2 publish or ack causes an * invalid transition for the internal state machine; * #MQTTSuccess on success. */ static MQTTStatus_t receiveSingleIteration( MQTTContext_t * pContext, uint32_t remainingTimeMs, bool manageKeepAlive ); /** * @brief Validates parameters of #MQTT_Subscribe or #MQTT_Unsubscribe. * * @param[in] pContext Initialized MQTT context. * @param[in] pSubscriptionList List of MQTT subscription info. * @param[in] subscriptionCount The number of elements in pSubscriptionList. * @param[in] packetId Packet identifier. * * @return #MQTTBadParameter if invalid parameters are passed; * #MQTTSuccess otherwise. */ static MQTTStatus_t validateSubscribeUnsubscribeParams( const MQTTContext_t * pContext, const MQTTSubscribeInfo_t * pSubscriptionList, size_t subscriptionCount, uint16_t packetId ); /** * @brief Send serialized publish packet using transport send. * * @brief param[in] pContext Initialized MQTT context. * @brief param[in] pPublishInfo MQTT PUBLISH packet parameters. * @brief param[in] headerSize Header size of the PUBLISH packet. * * @return #MQTTSendFailed if transport write failed; * #MQTTSuccess otherwise. */ static MQTTStatus_t sendPublish( MQTTContext_t * pContext, const MQTTPublishInfo_t * pPublishInfo, size_t headerSize ); /** * @brief Receives a CONNACK MQTT packet. * * @param[in] pContext Initialized MQTT context. * @param[in] timeoutMs Timeout for waiting for CONNACK packet. * @param[in] cleanSession Clean session flag set by application. * @param[out] pIncomingPacket List of MQTT subscription info. * @param[out] pSessionPresent Whether a previous session was present. * Only relevant if not establishing a clean session. * * @return #MQTTBadResponse if a bad response is received; * #MQTTNoDataAvailable if no data available for transport recv; * ##MQTTRecvFailed if transport recv failed; * #MQTTSuccess otherwise. */ static MQTTStatus_t receiveConnack( const MQTTContext_t * pContext, uint32_t timeoutMs, bool cleanSession, MQTTPacketInfo_t * pIncomingPacket, bool * pSessionPresent ); /** * @brief Resends pending acks for a re-established MQTT session, or * clears existing state records for a clean session. * * @param[in] pContext Initialized MQTT context. * @param[in] sessionPresent Session present flag received from the MQTT broker. * * @return #MQTTSendFailed if transport send during resend failed; * #MQTTSuccess otherwise. */ static MQTTStatus_t handleSessionResumption( MQTTContext_t * pContext, bool sessionPresent ); /** * @brief Serializes a PUBLISH message. * * @brief param[in] pContext Initialized MQTT context. * @brief param[in] pPublishInfo MQTT PUBLISH packet parameters. * @brief param[in] packetId Packet Id of the publish packet. * @brief param[out] pHeaderSize Size of the serialized PUBLISH header. * * @return #MQTTNoMemory if pBuffer is too small to hold the MQTT packet; * #MQTTBadParameter if invalid parameters are passed; * #MQTTSuccess otherwise. */ static MQTTStatus_t serializePublish( const MQTTContext_t * pContext, const MQTTPublishInfo_t * pPublishInfo, uint16_t packetId, size_t * const pHeaderSize ); /** * @brief Function to validate #MQTT_Publish parameters. * * @brief param[in] pContext Initialized MQTT context. * @brief param[in] pPublishInfo MQTT PUBLISH packet parameters. * @brief param[in] packetId Packet Id for the MQTT PUBLISH packet. * * @return #MQTTBadParameter if invalid parameters are passed; * #MQTTSuccess otherwise. */ static MQTTStatus_t validatePublishParams( const MQTTContext_t * pContext, const MQTTPublishInfo_t * pPublishInfo, uint16_t packetId ); /** * @brief Performs matching for special cases when a topic filter ends * with a wildcard character. * * When the topic name has been consumed but there are remaining characters to * to match in topic filter, this function handles the following 2 cases: * - When the topic filter ends with "/+" or "/#" characters, but the topic * name only ends with '/'. * - When the topic filter ends with "/#" characters, but the topic name * ends at the parent level. * * @note This function ASSUMES that the topic name been consumed in linear * matching with the topic filer, but the topic filter has remaining characters * to be matched. * * @param[in] pTopicFilter The topic filter containing the wildcard. * @param[in] topicFilterLength Length of the topic filter being examined. * @param[in] filterIndex Index of the topic filter being examined. * * @return Returns whether the topic filter and the topic name match. */ static bool matchEndWildcardsSpecialCases( const char * pTopicFilter, uint16_t topicFilterLength, uint16_t filterIndex ); /** * @brief Attempt to match topic name with a topic filter starting with a wildcard. * * If the topic filter starts with a '+' (single-level) wildcard, the function * advances the @a pNameIndex by a level in the topic name. * If the topic filter starts with a '#' (multi-level) wildcard, the function * concludes that both the topic name and topic filter match. * * @param[in] pTopicName The topic name to match. * @param[in] topicNameLength Length of the topic name. * @param[in] pTopicFilter The topic filter to match. * @param[in] topicFilterLength Length of the topic filter. * @param[in,out] pNameIndex Current index in the topic name being examined. It is * advanced by one level for `+` wildcards. * @param[in, out] pFilterIndex Current index in the topic filter being examined. * It is advanced to position of '/' level separator for '+' wildcard. * @param[out] pMatch Whether the topic filter and topic name match. * * @return `true` if the caller of this function should exit; `false` if the * caller should continue parsing the topics. */ static bool matchWildcards( const char * pTopicName, uint16_t topicNameLength, const char * pTopicFilter, uint16_t topicFilterLength, uint16_t * pNameIndex, uint16_t * pFilterIndex, bool * pMatch ); /** * @brief Match a topic name and topic filter allowing the use of wildcards. * * @param[in] pTopicName The topic name to check. * @param[in] topicNameLength Length of the topic name. * @param[in] pTopicFilter The topic filter to check. * @param[in] topicFilterLength Length of topic filter. * * @return `true` if the topic name and topic filter match; `false` otherwise. */ static bool matchTopicFilter( const char * pTopicName, uint16_t topicNameLength, const char * pTopicFilter, uint16_t topicFilterLength ); /*-----------------------------------------------------------*/ static bool matchEndWildcardsSpecialCases( const char * pTopicFilter, uint16_t topicFilterLength, uint16_t filterIndex ) { bool matchFound = false; assert( pTopicFilter != NULL ); assert( topicFilterLength != 0 ); /* Check if the topic filter has 2 remaining characters and it ends in * "/#". This check handles the case to match filter "sport/#" with topic * "sport". The reason is that the '#' wildcard represents the parent and * any number of child levels in the topic name.*/ if( ( topicFilterLength >= 3U ) && ( filterIndex == ( topicFilterLength - 3U ) ) && ( pTopicFilter[ filterIndex + 1U ] == '/' ) && ( pTopicFilter[ filterIndex + 2U ] == '#' ) ) { matchFound = true; } /* Check if the next character is "#" or "+" and the topic filter ends in * "/#" or "/+". This check handles the cases to match: * * - Topic filter "sport/+" with topic "sport/". * - Topic filter "sport/#" with topic "sport/". */ if( ( filterIndex == ( topicFilterLength - 2U ) ) && ( pTopicFilter[ filterIndex ] == '/' ) ) { /* Check that the last character is a wildcard. */ matchFound = ( ( pTopicFilter[ filterIndex + 1U ] == '+' ) || ( pTopicFilter[ filterIndex + 1U ] == '#' ) ) ? true : false; } return matchFound; } /*-----------------------------------------------------------*/ static bool matchWildcards( const char * pTopicName, uint16_t topicNameLength, const char * pTopicFilter, uint16_t topicFilterLength, uint16_t * pNameIndex, uint16_t * pFilterIndex, bool * pMatch ) { bool shouldStopMatching = false; bool locationIsValidForWildcard; assert( pTopicName != NULL ); assert( topicNameLength != 0 ); assert( pTopicFilter != NULL ); assert( topicFilterLength != 0 ); assert( pNameIndex != NULL ); assert( pFilterIndex != NULL ); assert( pMatch != NULL ); /* Wild card in a topic filter is only valid either at the starting position * or when it is preceded by a '/'.*/ locationIsValidForWildcard = ( ( *pFilterIndex == 0u ) || ( pTopicFilter[ *pFilterIndex - 1U ] == '/' ) ) ? true : false; if( ( pTopicFilter[ *pFilterIndex ] == '+' ) && ( locationIsValidForWildcard == true ) ) { bool nextLevelExistsInTopicName = false; bool nextLevelExistsinTopicFilter = false; /* Move topic name index to the end of the current level. The end of the * current level is identified by the last character before the next level * separator '/'. */ while( *pNameIndex < topicNameLength ) { /* Exit the loop if we hit the level separator. */ if( pTopicName[ *pNameIndex ] == '/' ) { nextLevelExistsInTopicName = true; break; } ( *pNameIndex )++; } /* Determine if the topic filter contains a child level after the current level * represented by the '+' wildcard. */ if( ( *pFilterIndex < ( topicFilterLength - 1U ) ) && ( pTopicFilter[ *pFilterIndex + 1U ] == '/' ) ) { nextLevelExistsinTopicFilter = true; } /* If the topic name contains a child level but the topic filter ends at * the current level, then there does not exist a match. */ if( ( nextLevelExistsInTopicName == true ) && ( nextLevelExistsinTopicFilter == false ) ) { *pMatch = false; shouldStopMatching = true; } /* If the topic name and topic filter have child levels, then advance the * filter index to the level separator in the topic filter, so that match * can be performed in the next level. * Note: The name index already points to the level separator in the topic * name. */ else if( nextLevelExistsInTopicName == true ) { ( *pFilterIndex )++; } else { /* If we have reached here, the the loop terminated on the * ( *pNameIndex < topicNameLength) condition, which means that have * reached past the end of the topic name, and thus, we decrement the * index to the last character in the topic name.*/ ( *pNameIndex )--; } } /* '#' matches everything remaining in the topic name. It must be the * last character in a topic filter. */ else if( ( pTopicFilter[ *pFilterIndex ] == '#' ) && ( *pFilterIndex == ( topicFilterLength - 1U ) ) && ( locationIsValidForWildcard == true ) ) { /* Subsequent characters don't need to be checked for the * multi-level wildcard. */ *pMatch = true; shouldStopMatching = true; } else { /* Any character mismatch other than '+' or '#' means the topic * name does not match the topic filter. */ *pMatch = false; shouldStopMatching = true; } return shouldStopMatching; } /*-----------------------------------------------------------*/ static bool matchTopicFilter( const char * pTopicName, uint16_t topicNameLength, const char * pTopicFilter, uint16_t topicFilterLength ) { bool matchFound = false, shouldStopMatching = false; uint16_t nameIndex = 0, filterIndex = 0; assert( pTopicName != NULL ); assert( topicNameLength != 0 ); assert( pTopicFilter != NULL ); assert( topicFilterLength != 0 ); while( ( nameIndex < topicNameLength ) && ( filterIndex < topicFilterLength ) ) { /* Check if the character in the topic name matches the corresponding * character in the topic filter string. */ if( pTopicName[ nameIndex ] == pTopicFilter[ filterIndex ] ) { /* If the topic name has been consumed but the topic filter has not * been consumed, match for special cases when the topic filter ends * with wildcard character. */ if( nameIndex == ( topicNameLength - 1U ) ) { matchFound = matchEndWildcardsSpecialCases( pTopicFilter, topicFilterLength, filterIndex ); } } else { /* Check for matching wildcards. */ shouldStopMatching = matchWildcards( pTopicName, topicNameLength, pTopicFilter, topicFilterLength, &nameIndex, &filterIndex, &matchFound ); } if( ( matchFound == true ) || ( shouldStopMatching == true ) ) { break; } /* Increment indexes. */ nameIndex++; filterIndex++; } if( matchFound == false ) { /* If the end of both strings has been reached, they match. This represents the * case when the topic filter contains the '+' wildcard at a non-starting position. * For example, when matching either of "sport/+/player" OR "sport/hockey/+" topic * filters with "sport/hockey/player" topic name. */ matchFound = ( ( nameIndex == topicNameLength ) && ( filterIndex == topicFilterLength ) ) ? true : false; } return matchFound; } /*-----------------------------------------------------------*/ static int32_t sendPacket( MQTTContext_t * pContext, const uint8_t * pBufferToSend, size_t bytesToSend ) { const uint8_t * pIndex = pBufferToSend; size_t bytesRemaining = bytesToSend; int32_t totalBytesSent = 0, bytesSent; uint32_t sendTime = 0U; bool sendError = false; assert( pContext != NULL ); assert( pContext->getTime != NULL ); assert( pContext->transportInterface.send != NULL ); assert( pIndex != NULL ); bytesRemaining = bytesToSend; /* Record the time of transmission. */ sendTime = pContext->getTime(); /* Loop until the entire packet is sent. */ while( ( bytesRemaining > 0UL ) && ( sendError == false ) ) { bytesSent = pContext->transportInterface.send( pContext->transportInterface.pNetworkContext, pIndex, bytesRemaining ); if( bytesSent < 0 ) { LogError( ( "Transport send failed. Error code=%d.", bytesSent ) ); totalBytesSent = bytesSent; sendError = true; } else { /* It is a bug in the application's transport send implementation if * more bytes than expected are sent. To avoid a possible overflow * in converting bytesRemaining from unsigned to signed, this assert * must exist after the check for bytesSent being negative. */ assert( ( size_t ) bytesSent <= bytesRemaining ); bytesRemaining -= ( size_t ) bytesSent; totalBytesSent += bytesSent; pIndex += bytesSent; LogDebug( ( "BytesSent=%d, BytesRemaining=%lu," " TotalBytesSent=%d.", bytesSent, ( unsigned long ) bytesRemaining, totalBytesSent ) ); } } /* Update time of last transmission if the entire packet is successfully sent. */ if( totalBytesSent > 0 ) { pContext->lastPacketTime = sendTime; LogDebug( ( "Successfully sent packet at time %u.", sendTime ) ); } return totalBytesSent; } /*-----------------------------------------------------------*/ static uint32_t calculateElapsedTime( uint32_t later, uint32_t start ) { return later - start; } /*-----------------------------------------------------------*/ static MQTTPubAckType_t getAckFromPacketType( uint8_t packetType ) { MQTTPubAckType_t ackType = MQTTPuback; switch( packetType ) { case MQTT_PACKET_TYPE_PUBACK: ackType = MQTTPuback; break; case MQTT_PACKET_TYPE_PUBREC: ackType = MQTTPubrec; break; case MQTT_PACKET_TYPE_PUBREL: ackType = MQTTPubrel; break; case MQTT_PACKET_TYPE_PUBCOMP: default: /* This function is only called after checking the type is one of * the above four values, so packet type must be PUBCOMP here. */ assert( packetType == MQTT_PACKET_TYPE_PUBCOMP ); ackType = MQTTPubcomp; break; } return ackType; } /*-----------------------------------------------------------*/ static int32_t recvExact( const MQTTContext_t * pContext, size_t bytesToRecv, uint32_t timeoutMs ) { uint8_t * pIndex = NULL; size_t bytesRemaining = bytesToRecv; int32_t totalBytesRecvd = 0, bytesRecvd; uint32_t entryTimeMs = 0U, elapsedTimeMs = 0U; TransportRecv_t recvFunc = NULL; MQTTGetCurrentTimeFunc_t getTimeStampMs = NULL; bool receiveError = false; assert( pContext != NULL ); assert( bytesToRecv <= pContext->networkBuffer.size ); assert( pContext->getTime != NULL ); assert( pContext->transportInterface.recv != NULL ); assert( pContext->networkBuffer.pBuffer != NULL ); pIndex = pContext->networkBuffer.pBuffer; recvFunc = pContext->transportInterface.recv; getTimeStampMs = pContext->getTime; entryTimeMs = getTimeStampMs(); while( ( bytesRemaining > 0U ) && ( receiveError == false ) ) { bytesRecvd = recvFunc( pContext->transportInterface.pNetworkContext, pIndex, bytesRemaining ); if( bytesRecvd < 0 ) { LogError( ( "Network error while receiving packet: ReturnCode=%d.", bytesRecvd ) ); totalBytesRecvd = bytesRecvd; receiveError = true; } else { /* It is a bug in the application's transport receive implementation * if more bytes than expected are received. To avoid a possible * overflow in converting bytesRemaining from unsigned to signed, * this assert must exist after the check for bytesRecvd being * negative. */ assert( ( size_t ) bytesRecvd <= bytesRemaining ); bytesRemaining -= ( size_t ) bytesRecvd; totalBytesRecvd += ( int32_t ) bytesRecvd; pIndex += bytesRecvd; LogDebug( ( "BytesReceived=%d, BytesRemaining=%lu, " "TotalBytesReceived=%d.", bytesRecvd, ( unsigned long ) bytesRemaining, totalBytesRecvd ) ); } elapsedTimeMs = calculateElapsedTime( getTimeStampMs(), entryTimeMs ); if( ( bytesRemaining > 0U ) && ( elapsedTimeMs >= timeoutMs ) ) { LogError( ( "Time expired while receiving packet." ) ); receiveError = true; } } return totalBytesRecvd; } /*-----------------------------------------------------------*/ static MQTTStatus_t discardPacket( const MQTTContext_t * pContext, size_t remainingLength, uint32_t timeoutMs ) { MQTTStatus_t status = MQTTRecvFailed; int32_t bytesReceived = 0; size_t bytesToReceive = 0U; uint32_t totalBytesReceived = 0U, entryTimeMs = 0U, elapsedTimeMs = 0U; uint32_t remainingTimeMs = timeoutMs; MQTTGetCurrentTimeFunc_t getTimeStampMs = NULL; bool receiveError = false; assert( pContext != NULL ); assert( pContext->getTime != NULL ); bytesToReceive = pContext->networkBuffer.size; getTimeStampMs = pContext->getTime; entryTimeMs = getTimeStampMs(); while( ( totalBytesReceived < remainingLength ) && ( receiveError == false ) ) { if( ( remainingLength - totalBytesReceived ) < bytesToReceive ) { bytesToReceive = remainingLength - totalBytesReceived; } bytesReceived = recvExact( pContext, bytesToReceive, remainingTimeMs ); if( bytesReceived != ( int32_t ) bytesToReceive ) { LogError( ( "Receive error while discarding packet." "ReceivedBytes=%d, ExpectedBytes=%lu.", bytesReceived, ( unsigned long ) bytesToReceive ) ); receiveError = true; } else { totalBytesReceived += ( uint32_t ) bytesReceived; elapsedTimeMs = calculateElapsedTime( getTimeStampMs(), entryTimeMs ); /* Update remaining time and check for timeout. */ if( elapsedTimeMs < timeoutMs ) { remainingTimeMs = timeoutMs - elapsedTimeMs; } else { LogError( ( "Time expired while discarding packet." ) ); receiveError = true; } } } if( totalBytesReceived == remainingLength ) { LogError( ( "Dumped packet. DumpedBytes=%d.", totalBytesReceived ) ); /* Packet dumped, so no data is available. */ status = MQTTNoDataAvailable; } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t receivePacket( const MQTTContext_t * pContext, MQTTPacketInfo_t incomingPacket, uint32_t remainingTimeMs ) { MQTTStatus_t status = MQTTSuccess; int32_t bytesReceived = 0; size_t bytesToReceive = 0U; assert( pContext != NULL ); assert( pContext->networkBuffer.pBuffer != NULL ); if( incomingPacket.remainingLength > pContext->networkBuffer.size ) { LogError( ( "Incoming packet will be dumped: " "Packet length exceeds network buffer size." "PacketSize=%lu, NetworkBufferSize=%lu.", ( unsigned long ) incomingPacket.remainingLength, ( unsigned long ) pContext->networkBuffer.size ) ); status = discardPacket( pContext, incomingPacket.remainingLength, remainingTimeMs ); } else { bytesToReceive = incomingPacket.remainingLength; bytesReceived = recvExact( pContext, bytesToReceive, remainingTimeMs ); if( bytesReceived == ( int32_t ) bytesToReceive ) { /* Receive successful, bytesReceived == bytesToReceive. */ LogInfo( ( "Packet received. ReceivedBytes=%d.", bytesReceived ) ); } else { LogError( ( "Packet reception failed. ReceivedBytes=%d, " "ExpectedBytes=%lu.", bytesReceived, ( unsigned long ) bytesToReceive ) ); status = MQTTRecvFailed; } } return status; } /*-----------------------------------------------------------*/ static uint8_t getAckTypeToSend( MQTTPublishState_t state ) { uint8_t packetTypeByte = 0U; switch( state ) { case MQTTPubAckSend: packetTypeByte = MQTT_PACKET_TYPE_PUBACK; break; case MQTTPubRecSend: packetTypeByte = MQTT_PACKET_TYPE_PUBREC; break; case MQTTPubRelSend: packetTypeByte = MQTT_PACKET_TYPE_PUBREL; break; case MQTTPubCompSend: packetTypeByte = MQTT_PACKET_TYPE_PUBCOMP; break; default: /* Take no action for states that do not require sending an ack. */ break; } return packetTypeByte; } /*-----------------------------------------------------------*/ static MQTTStatus_t sendPublishAcks( MQTTContext_t * pContext, uint16_t packetId, MQTTPublishState_t publishState ) { MQTTStatus_t status = MQTTSuccess; MQTTPublishState_t newState = MQTTStateNull; int32_t bytesSent = 0; uint8_t packetTypeByte = 0U; MQTTPubAckType_t packetType; assert( pContext != NULL ); packetTypeByte = getAckTypeToSend( publishState ); if( packetTypeByte != 0U ) { packetType = getAckFromPacketType( packetTypeByte ); status = MQTT_SerializeAck( &( pContext->networkBuffer ), packetTypeByte, packetId ); if( status == MQTTSuccess ) { bytesSent = sendPacket( pContext, pContext->networkBuffer.pBuffer, MQTT_PUBLISH_ACK_PACKET_SIZE ); } if( bytesSent == ( int32_t ) MQTT_PUBLISH_ACK_PACKET_SIZE ) { pContext->controlPacketSent = true; status = MQTT_UpdateStateAck( pContext, packetId, packetType, MQTT_SEND, &newState ); if( status != MQTTSuccess ) { LogError( ( "Failed to update state of publish %u.", packetId ) ); } } else { LogError( ( "Failed to send ACK packet: PacketType=%02x, " "SentBytes=%d, " "PacketSize=%lu.", packetTypeByte, bytesSent, MQTT_PUBLISH_ACK_PACKET_SIZE ) ); status = MQTTSendFailed; } } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t handleKeepAlive( MQTTContext_t * pContext ) { MQTTStatus_t status = MQTTSuccess; uint32_t now = 0U, keepAliveMs = 0U; assert( pContext != NULL ); assert( pContext->getTime != NULL ); now = pContext->getTime(); keepAliveMs = 1000U * ( uint32_t ) pContext->keepAliveIntervalSec; /* If keep alive interval is 0, it is disabled. */ if( ( keepAliveMs != 0U ) && ( calculateElapsedTime( now, pContext->lastPacketTime ) > keepAliveMs ) ) { if( pContext->waitingForPingResp == true ) { /* Has time expired? */ if( calculateElapsedTime( now, pContext->pingReqSendTimeMs ) > MQTT_PINGRESP_TIMEOUT_MS ) { status = MQTTKeepAliveTimeout; } } else { status = MQTT_Ping( pContext ); } } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t handleIncomingPublish( MQTTContext_t * pContext, MQTTPacketInfo_t * pIncomingPacket ) { MQTTStatus_t status = MQTTBadParameter; MQTTPublishState_t publishRecordState = MQTTStateNull; uint16_t packetIdentifier = 0U; MQTTPublishInfo_t publishInfo; MQTTDeserializedInfo_t deserializedInfo; bool duplicatePublish = false; assert( pContext != NULL ); assert( pIncomingPacket != NULL ); assert( pContext->appCallback != NULL ); status = MQTT_DeserializePublish( pIncomingPacket, &packetIdentifier, &publishInfo ); LogInfo( ( "De-serialized incoming PUBLISH packet: DeserializerResult=%s.", MQTT_Status_strerror( status ) ) ); if( status == MQTTSuccess ) { status = MQTT_UpdateStatePublish( pContext, packetIdentifier, MQTT_RECEIVE, publishInfo.qos, &publishRecordState ); if( status == MQTTSuccess ) { LogInfo( ( "State record updated. New state=%s.", MQTT_State_strerror( publishRecordState ) ) ); } /* Different cases in which an incoming publish with duplicate flag is * handled are as listed below. * 1. No collision - This is the first instance of the incoming publish * packet received or an earlier received packet state is lost. This * will be handled as a new incoming publish for both QoS1 and QoS2 * publishes. * 2. Collision - The incoming packet was received before and a state * record is present in the state engine. For QoS1 and QoS2 publishes * this case can happen at 2 different cases and handling is * different. * a. QoS1 - If a PUBACK is not successfully sent for the incoming * publish due to a connection issue, it can result in broker * sending out a duplicate publish with dup flag set, when a * session is reestablished. It can result in a collision in * state engine. This will be handled by processing the incoming * publish as a new publish ignoring the * #MQTTStateCollision status from the state engine. The publish * data is not passed to the application. * b. QoS2 - If a PUBREC is not successfully sent for the incoming * publish or the PUBREC sent is not successfully received by the * broker due to a connection issue, it can result in broker * sending out a duplicate publish with dup flag set, when a * session is reestablished. It can result in a collision in * state engine. This will be handled by ignoring the * #MQTTStateCollision status from the state engine. The publish * data is not passed to the application. */ else if( status == MQTTStateCollision ) { status = MQTTSuccess; duplicatePublish = true; /* Calculate the state for the ack packet that needs to be sent out * for the duplicate incoming publish. */ publishRecordState = MQTT_CalculateStatePublish( MQTT_RECEIVE, publishInfo.qos ); LogDebug( ( "Incoming publish packet with packet id %u already exists.", packetIdentifier ) ); if( publishInfo.dup == false ) { LogError( ( "DUP flag is 0 for duplicate packet (MQTT-3.3.1.-1)." ) ); } } else { LogError( ( "Error in updating publish state for incoming publish with packet id %u." " Error is %s", packetIdentifier, MQTT_Status_strerror( status ) ) ); } } if( status == MQTTSuccess ) { /* Set fields of deserialized struct. */ deserializedInfo.packetIdentifier = packetIdentifier; deserializedInfo.pPublishInfo = &publishInfo; deserializedInfo.deserializationResult = status; /* Invoke application callback to hand the buffer over to application * before sending acks. * Application callback will be invoked for all publishes, except for * duplicate incoming publishes. */ if( duplicatePublish == false ) { pContext->appCallback( pContext, pIncomingPacket, &deserializedInfo ); } /* Send PUBACK or PUBREC if necessary. */ status = sendPublishAcks( pContext, packetIdentifier, publishRecordState ); } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t handlePublishAcks( MQTTContext_t * pContext, MQTTPacketInfo_t * pIncomingPacket ) { MQTTStatus_t status = MQTTBadResponse; MQTTPublishState_t publishRecordState = MQTTStateNull; uint16_t packetIdentifier; MQTTPubAckType_t ackType; MQTTEventCallback_t appCallback; MQTTDeserializedInfo_t deserializedInfo; assert( pContext != NULL ); assert( pIncomingPacket != NULL ); assert( pContext->appCallback != NULL ); appCallback = pContext->appCallback; ackType = getAckFromPacketType( pIncomingPacket->type ); status = MQTT_DeserializeAck( pIncomingPacket, &packetIdentifier, NULL ); LogInfo( ( "Ack packet deserialized with result: %s.", MQTT_Status_strerror( status ) ) ); if( status == MQTTSuccess ) { status = MQTT_UpdateStateAck( pContext, packetIdentifier, ackType, MQTT_RECEIVE, &publishRecordState ); if( status == MQTTSuccess ) { LogInfo( ( "State record updated. New state=%s.", MQTT_State_strerror( publishRecordState ) ) ); } else { LogError( ( "Updating the state engine for packet id %u" " failed with error %s.", packetIdentifier, MQTT_Status_strerror( status ) ) ); } } if( status == MQTTSuccess ) { /* Set fields of deserialized struct. */ deserializedInfo.packetIdentifier = packetIdentifier; deserializedInfo.deserializationResult = status; deserializedInfo.pPublishInfo = NULL; /* Invoke application callback to hand the buffer over to application * before sending acks. */ appCallback( pContext, pIncomingPacket, &deserializedInfo ); /* Send PUBREL or PUBCOMP if necessary. */ status = sendPublishAcks( pContext, packetIdentifier, publishRecordState ); } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t handleIncomingAck( MQTTContext_t * pContext, MQTTPacketInfo_t * pIncomingPacket, bool manageKeepAlive ) { MQTTStatus_t status = MQTTBadResponse; uint16_t packetIdentifier = MQTT_PACKET_ID_INVALID; MQTTDeserializedInfo_t deserializedInfo; /* We should always invoke the app callback unless we receive a PINGRESP * and are managing keep alive, or if we receive an unknown packet. We * initialize this to false since the callback must be invoked before * sending any PUBREL or PUBCOMP. However, for other cases, we invoke it * at the end to reduce the complexity of this function. */ bool invokeAppCallback = false; MQTTEventCallback_t appCallback = NULL; assert( pContext != NULL ); assert( pIncomingPacket != NULL ); assert( pContext->appCallback != NULL ); appCallback = pContext->appCallback; LogDebug( ( "Received packet of type %02x.", pIncomingPacket->type ) ); switch( pIncomingPacket->type ) { case MQTT_PACKET_TYPE_PUBACK: case MQTT_PACKET_TYPE_PUBREC: case MQTT_PACKET_TYPE_PUBREL: case MQTT_PACKET_TYPE_PUBCOMP: /* Handle all the publish acks. The app callback is invoked here. */ status = handlePublishAcks( pContext, pIncomingPacket ); break; case MQTT_PACKET_TYPE_PINGRESP: status = MQTT_DeserializeAck( pIncomingPacket, &packetIdentifier, NULL ); invokeAppCallback = ( ( status == MQTTSuccess ) && ( manageKeepAlive == false ) ) ? true : false; if( ( status == MQTTSuccess ) && ( manageKeepAlive == true ) ) { pContext->waitingForPingResp = false; } break; case MQTT_PACKET_TYPE_SUBACK: case MQTT_PACKET_TYPE_UNSUBACK: /* Deserialize and give these to the app provided callback. */ status = MQTT_DeserializeAck( pIncomingPacket, &packetIdentifier, NULL ); invokeAppCallback = ( ( status == MQTTSuccess ) || ( status == MQTTServerRefused ) ) ? true : false; break; default: /* Bad response from the server. */ LogError( ( "Unexpected packet type from server: PacketType=%02x.", pIncomingPacket->type ) ); status = MQTTBadResponse; break; } if( invokeAppCallback == true ) { /* Set fields of deserialized struct. */ deserializedInfo.packetIdentifier = packetIdentifier; deserializedInfo.deserializationResult = status; deserializedInfo.pPublishInfo = NULL; appCallback( pContext, pIncomingPacket, &deserializedInfo ); /* In case a SUBACK indicated refusal, reset the status to continue the loop. */ status = MQTTSuccess; } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t receiveSingleIteration( MQTTContext_t * pContext, uint32_t remainingTimeMs, bool manageKeepAlive ) { MQTTStatus_t status = MQTTSuccess; MQTTPacketInfo_t incomingPacket; assert( pContext != NULL ); assert( pContext->networkBuffer.pBuffer != NULL ); status = MQTT_GetIncomingPacketTypeAndLength( pContext->transportInterface.recv, pContext->transportInterface.pNetworkContext, &incomingPacket ); if( status == MQTTNoDataAvailable ) { if( manageKeepAlive == true ) { /* Assign status so an error can be bubbled up to application, * but reset it on success. */ status = handleKeepAlive( pContext ); } if( status == MQTTSuccess ) { /* Reset the status to indicate that we should not try to read * a packet from the transport interface. */ status = MQTTNoDataAvailable; } } else if( status != MQTTSuccess ) { LogError( ( "Receiving incoming packet length failed. Status=%s", MQTT_Status_strerror( status ) ) ); } else { /* Receive packet. Remaining time is recalculated before calling this * function. */ status = receivePacket( pContext, incomingPacket, remainingTimeMs ); } /* Handle received packet. If no data was read then this will not execute. */ if( status == MQTTSuccess ) { incomingPacket.pRemainingData = pContext->networkBuffer.pBuffer; /* PUBLISH packets allow flags in the lower four bits. For other * packet types, they are reserved. */ if( ( incomingPacket.type & 0xF0U ) == MQTT_PACKET_TYPE_PUBLISH ) { status = handleIncomingPublish( pContext, &incomingPacket ); } else { status = handleIncomingAck( pContext, &incomingPacket, manageKeepAlive ); } } if( status == MQTTNoDataAvailable ) { /* No data available is not an error. Reset to MQTTSuccess so the * return code will indicate success. */ status = MQTTSuccess; } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t validateSubscribeUnsubscribeParams( const MQTTContext_t * pContext, const MQTTSubscribeInfo_t * pSubscriptionList, size_t subscriptionCount, uint16_t packetId ) { MQTTStatus_t status = MQTTSuccess; /* Validate all the parameters. */ if( ( pContext == NULL ) || ( pSubscriptionList == NULL ) ) { LogError( ( "Argument cannot be NULL: pContext=%p, " "pSubscriptionList=%p.", ( void * ) pContext, ( void * ) pSubscriptionList ) ); status = MQTTBadParameter; } else if( subscriptionCount == 0UL ) { LogError( ( "Subscription count is 0." ) ); status = MQTTBadParameter; } else if( packetId == 0U ) { LogError( ( "Packet Id for subscription packet is 0." ) ); status = MQTTBadParameter; } else { /* Empty else MISRA 15.7 */ } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t sendPublish( MQTTContext_t * pContext, const MQTTPublishInfo_t * pPublishInfo, size_t headerSize ) { MQTTStatus_t status = MQTTSuccess; int32_t bytesSent = 0; assert( pContext != NULL ); assert( pPublishInfo != NULL ); assert( headerSize > 0 ); assert( pContext->networkBuffer.pBuffer != NULL ); assert( !( pPublishInfo->payloadLength > 0 ) || ( pPublishInfo->pPayload != NULL ) ); /* Send header first. */ bytesSent = sendPacket( pContext, pContext->networkBuffer.pBuffer, headerSize ); if( bytesSent < 0 ) { LogError( ( "Transport send failed for PUBLISH header." ) ); status = MQTTSendFailed; } else { LogDebug( ( "Sent %d bytes of PUBLISH header.", bytesSent ) ); /* Send Payload if there is one to send. It is valid for a PUBLISH * Packet to contain a zero length payload.*/ if( pPublishInfo->payloadLength > 0U ) { bytesSent = sendPacket( pContext, pPublishInfo->pPayload, pPublishInfo->payloadLength ); if( bytesSent < 0 ) { LogError( ( "Transport send failed for PUBLISH payload." ) ); status = MQTTSendFailed; } else { LogDebug( ( "Sent %d bytes of PUBLISH payload.", bytesSent ) ); } } else { LogDebug( ( "PUBLISH payload was not sent. Payload length was zero." ) ); } } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t receiveConnack( const MQTTContext_t * pContext, uint32_t timeoutMs, bool cleanSession, MQTTPacketInfo_t * pIncomingPacket, bool * pSessionPresent ) { MQTTStatus_t status = MQTTSuccess; MQTTGetCurrentTimeFunc_t getTimeStamp = NULL; uint32_t entryTimeMs = 0U, remainingTimeMs = 0U, timeTakenMs = 0U; bool breakFromLoop = false; uint16_t loopCount = 0U; assert( pContext != NULL ); assert( pIncomingPacket != NULL ); assert( pContext->getTime != NULL ); getTimeStamp = pContext->getTime; /* Get the entry time for the function. */ entryTimeMs = getTimeStamp(); do { /* Transport read for incoming CONNACK packet type and length. * MQTT_GetIncomingPacketTypeAndLength is a blocking call and it is * returned after a transport receive timeout, an error, or a successful * receive of packet type and length. */ status = MQTT_GetIncomingPacketTypeAndLength( pContext->transportInterface.recv, pContext->transportInterface.pNetworkContext, pIncomingPacket ); /* The loop times out based on 2 conditions. * 1. If timeoutMs is greater than 0: * Loop times out based on the timeout calculated by getTime() * function. * 2. If timeoutMs is 0: * Loop times out based on the maximum number of retries config * MQTT_MAX_CONNACK_RECEIVE_RETRY_COUNT. This config will control * maximum the number of retry attempts to read the CONNACK packet. * A value of 0 for the config will try once to read CONNACK. */ if( timeoutMs > 0U ) { breakFromLoop = ( calculateElapsedTime( getTimeStamp(), entryTimeMs ) >= timeoutMs ) ? true : false; } else { breakFromLoop = ( loopCount >= MQTT_MAX_CONNACK_RECEIVE_RETRY_COUNT ) ? true : false; loopCount++; } /* Loop until there is data to read or if we have exceeded the timeout/retries. */ } while( ( status == MQTTNoDataAvailable ) && ( breakFromLoop == false ) ); if( status == MQTTSuccess ) { /* Time taken in this function so far. */ timeTakenMs = calculateElapsedTime( getTimeStamp(), entryTimeMs ); if( timeTakenMs < timeoutMs ) { /* Calculate remaining time for receiving the remainder of * the packet. */ remainingTimeMs = timeoutMs - timeTakenMs; } /* Reading the remainder of the packet by transport recv. * Attempt to read once even if the timeout has expired. * Invoking receivePacket with remainingTime as 0 would attempt to * recv from network once. If using retries, the remainder of the * CONNACK packet is tried to be read only once. Reading once would be * good as the packet type and remaining length was already read. Hence, * the probability of the remaining 2 bytes available to read is very high. */ if( pIncomingPacket->type == MQTT_PACKET_TYPE_CONNACK ) { status = receivePacket( pContext, *pIncomingPacket, remainingTimeMs ); } else { LogError( ( "Incorrect packet type %X received while expecting" " CONNACK(%X).", pIncomingPacket->type, MQTT_PACKET_TYPE_CONNACK ) ); status = MQTTBadResponse; } } if( status == MQTTSuccess ) { /* Update the packet info pointer to the buffer read. */ pIncomingPacket->pRemainingData = pContext->networkBuffer.pBuffer; /* Deserialize CONNACK. */ status = MQTT_DeserializeAck( pIncomingPacket, NULL, pSessionPresent ); } /* If a clean session is requested, a session present should not be set by * broker. */ if( status == MQTTSuccess ) { if( ( cleanSession == true ) && ( *pSessionPresent == true ) ) { LogError( ( "Unexpected session present flag in CONNACK response from broker." " CONNECT request with clean session was made with broker." ) ); status = MQTTBadResponse; } } if( status == MQTTSuccess ) { LogInfo( ( "Received MQTT CONNACK successfully from broker." ) ); } else { LogError( ( "CONNACK recv failed with status = %s.", MQTT_Status_strerror( status ) ) ); } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t handleSessionResumption( MQTTContext_t * pContext, bool sessionPresent ) { MQTTStatus_t status = MQTTSuccess; MQTTStateCursor_t cursor = MQTT_STATE_CURSOR_INITIALIZER; uint16_t packetId = MQTT_PACKET_ID_INVALID; MQTTPublishState_t state = MQTTStateNull; assert( pContext != NULL ); if( sessionPresent == true ) { /* Get the next packet ID for which a PUBREL need to be resent. */ packetId = MQTT_PubrelToResend( pContext, &cursor, &state ); /* Resend all the PUBREL acks after session is reestablished. */ while( ( packetId != MQTT_PACKET_ID_INVALID ) && ( status == MQTTSuccess ) ) { status = sendPublishAcks( pContext, packetId, state ); packetId = MQTT_PubrelToResend( pContext, &cursor, &state ); } } else { /* Clear any existing records if a new session is established. */ ( void ) memset( pContext->outgoingPublishRecords, 0x00, sizeof( pContext->outgoingPublishRecords ) ); ( void ) memset( pContext->incomingPublishRecords, 0x00, sizeof( pContext->incomingPublishRecords ) ); } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t serializePublish( const MQTTContext_t * pContext, const MQTTPublishInfo_t * pPublishInfo, uint16_t packetId, size_t * const pHeaderSize ) { MQTTStatus_t status = MQTTSuccess; size_t remainingLength = 0UL, packetSize = 0UL; assert( pContext != NULL ); assert( pPublishInfo != NULL ); assert( pHeaderSize != NULL ); /* Get the remaining length and packet size.*/ status = MQTT_GetPublishPacketSize( pPublishInfo, &remainingLength, &packetSize ); LogDebug( ( "PUBLISH packet size is %lu and remaining length is %lu.", ( unsigned long ) packetSize, ( unsigned long ) remainingLength ) ); if( status == MQTTSuccess ) { status = MQTT_SerializePublishHeader( pPublishInfo, packetId, remainingLength, &( pContext->networkBuffer ), pHeaderSize ); LogDebug( ( "Serialized PUBLISH header size is %lu.", ( unsigned long ) *pHeaderSize ) ); } return status; } /*-----------------------------------------------------------*/ static MQTTStatus_t validatePublishParams( const MQTTContext_t * pContext, const MQTTPublishInfo_t * pPublishInfo, uint16_t packetId ) { MQTTStatus_t status = MQTTSuccess; /* Validate arguments. */ if( ( pContext == NULL ) || ( pPublishInfo == NULL ) ) { LogError( ( "Argument cannot be NULL: pContext=%p, " "pPublishInfo=%p.", ( void * ) pContext, ( void * ) pPublishInfo ) ); status = MQTTBadParameter; } else if( ( pPublishInfo->qos != MQTTQoS0 ) && ( packetId == 0U ) ) { LogError( ( "Packet Id is 0 for PUBLISH with QoS=%u.", pPublishInfo->qos ) ); status = MQTTBadParameter; } else if( ( pPublishInfo->payloadLength > 0U ) && ( pPublishInfo->pPayload == NULL ) ) { LogError( ( "A nonzero payload length requires a non-NULL payload: " "payloadLength=%lu, pPayload=%p.", ( unsigned long ) pPublishInfo->payloadLength, pPublishInfo->pPayload ) ); status = MQTTBadParameter; } else { /* Empty else MISRA 15.7 */ } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_Init( MQTTContext_t * pContext, const TransportInterface_t * pTransportInterface, MQTTGetCurrentTimeFunc_t getTimeFunction, MQTTEventCallback_t userCallback, const MQTTFixedBuffer_t * pNetworkBuffer, void * userData ) { MQTTStatus_t status = MQTTSuccess; /* Validate arguments. */ if( ( pContext == NULL ) || ( pTransportInterface == NULL ) || ( pNetworkBuffer == NULL ) ) { LogError( ( "Argument cannot be NULL: pContext=%p, " "pTransportInterface=%p, " "pNetworkBuffer=%p", ( void * ) pContext, ( void * ) pTransportInterface, ( void * ) pNetworkBuffer ) ); status = MQTTBadParameter; } else if( getTimeFunction == NULL ) { LogError( ( "Invalid parameter: getTimeFunction is NULL" ) ); status = MQTTBadParameter; } else if( userCallback == NULL ) { LogError( ( "Invalid parameter: userCallback is NULL" ) ); status = MQTTBadParameter; } else if( pTransportInterface->recv == NULL ) { LogError( ( "Invalid parameter: pTransportInterface->recv is NULL" ) ); status = MQTTBadParameter; } else if( pTransportInterface->send == NULL ) { LogError( ( "Invalid parameter: pTransportInterface->send is NULL" ) ); status = MQTTBadParameter; } else { ( void ) memset( pContext, 0x00, sizeof( MQTTContext_t ) ); pContext->connectStatus = MQTTNotConnected; pContext->transportInterface = *pTransportInterface; pContext->getTime = getTimeFunction; pContext->appCallback = userCallback; pContext->networkBuffer = *pNetworkBuffer; pContext->userData = userData; /* Zero is not a valid packet ID per MQTT spec. Start from 1. */ pContext->nextPacketId = 1; } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_Connect( MQTTContext_t * pContext, const MQTTConnectInfo_t * pConnectInfo, const MQTTPublishInfo_t * pWillInfo, uint32_t timeoutMs, bool * pSessionPresent ) { size_t remainingLength = 0UL, packetSize = 0UL; int32_t bytesSent; MQTTStatus_t status = MQTTSuccess; MQTTPacketInfo_t incomingPacket = { 0 }; incomingPacket.type = ( uint8_t ) 0; if( ( pContext == NULL ) || ( pConnectInfo == NULL ) || ( pSessionPresent == NULL ) ) { LogError( ( "Argument cannot be NULL: pContext=%p, " "pConnectInfo=%p, pSessionPresent=%p.", ( void * ) pContext, ( void * ) pConnectInfo, ( void * ) pSessionPresent ) ); status = MQTTBadParameter; } if( status == MQTTSuccess ) { /* Get MQTT connect packet size and remaining length. */ status = MQTT_GetConnectPacketSize( pConnectInfo, pWillInfo, &remainingLength, &packetSize ); LogDebug( ( "CONNECT packet size is %lu and remaining length is %lu.", ( unsigned long ) packetSize, ( unsigned long ) remainingLength ) ); } if( status == MQTTSuccess ) { status = MQTT_SerializeConnect( pConnectInfo, pWillInfo, remainingLength, &( pContext->networkBuffer ) ); } if( status == MQTTSuccess ) { bytesSent = sendPacket( pContext, pContext->networkBuffer.pBuffer, packetSize ); if( bytesSent < 0 ) { LogError( ( "Transport send failed for CONNECT packet." ) ); status = MQTTSendFailed; } else { LogDebug( ( "Sent %d bytes of CONNECT packet.", bytesSent ) ); } } /* Read CONNACK from transport layer. */ if( status == MQTTSuccess ) { status = receiveConnack( pContext, timeoutMs, pConnectInfo->cleanSession, &incomingPacket, pSessionPresent ); } if( status == MQTTSuccess ) { /* Resend PUBRELs when reestablishing a session, or clear records for new sessions. */ status = handleSessionResumption( pContext, *pSessionPresent ); } if( status == MQTTSuccess ) { LogInfo( ( "MQTT connection established with the broker." ) ); pContext->connectStatus = MQTTConnected; /* Initialize keep-alive fields after a successful connection. */ pContext->keepAliveIntervalSec = pConnectInfo->keepAliveSeconds; pContext->waitingForPingResp = false; pContext->pingReqSendTimeMs = 0U; } else { LogError( ( "MQTT connection failed with status = %s.", MQTT_Status_strerror( status ) ) ); } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_Subscribe( MQTTContext_t * pContext, const MQTTSubscribeInfo_t * pSubscriptionList, size_t subscriptionCount, uint16_t packetId ) { size_t remainingLength = 0UL, packetSize = 0UL; int32_t bytesSent = 0; /* Validate arguments. */ MQTTStatus_t status = validateSubscribeUnsubscribeParams( pContext, pSubscriptionList, subscriptionCount, packetId ); if( status == MQTTSuccess ) { /* Get the remaining length and packet size.*/ status = MQTT_GetSubscribePacketSize( pSubscriptionList, subscriptionCount, &remainingLength, &packetSize ); LogDebug( ( "SUBSCRIBE packet size is %lu and remaining length is %lu.", ( unsigned long ) packetSize, ( unsigned long ) remainingLength ) ); } if( status == MQTTSuccess ) { /* Serialize MQTT SUBSCRIBE packet. */ status = MQTT_SerializeSubscribe( pSubscriptionList, subscriptionCount, packetId, remainingLength, &( pContext->networkBuffer ) ); } if( status == MQTTSuccess ) { /* Send serialized MQTT SUBSCRIBE packet to transport layer. */ bytesSent = sendPacket( pContext, pContext->networkBuffer.pBuffer, packetSize ); if( bytesSent < 0 ) { LogError( ( "Transport send failed for SUBSCRIBE packet." ) ); status = MQTTSendFailed; } else { LogDebug( ( "Sent %d bytes of SUBSCRIBE packet.", bytesSent ) ); } } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_Publish( MQTTContext_t * pContext, const MQTTPublishInfo_t * pPublishInfo, uint16_t packetId ) { size_t headerSize = 0UL; MQTTPublishState_t publishStatus = MQTTStateNull; /* Validate arguments. */ MQTTStatus_t status = validatePublishParams( pContext, pPublishInfo, packetId ); if( status == MQTTSuccess ) { /* Serialize PUBLISH packet. */ status = serializePublish( pContext, pPublishInfo, packetId, &headerSize ); } if( ( status == MQTTSuccess ) && ( pPublishInfo->qos > MQTTQoS0 ) ) { /* Reserve state for publish message. Only to be done for QoS1 or QoS2. */ status = MQTT_ReserveState( pContext, packetId, pPublishInfo->qos ); /* State already exists for a duplicate packet. * If a state doesn't exist, it will be handled as a new publish in * state engine. */ if( ( status == MQTTStateCollision ) && ( pPublishInfo->dup == true ) ) { status = MQTTSuccess; } } if( status == MQTTSuccess ) { /* Sends the serialized publish packet over network. */ status = sendPublish( pContext, pPublishInfo, headerSize ); } if( ( status == MQTTSuccess ) && ( pPublishInfo->qos > MQTTQoS0 ) ) { /* Update state machine after PUBLISH is sent. * Only to be done for QoS1 or QoS2. */ status = MQTT_UpdateStatePublish( pContext, packetId, MQTT_SEND, pPublishInfo->qos, &publishStatus ); if( status != MQTTSuccess ) { LogError( ( "Update state for publish failed with status %s." " However PUBLISH packet was sent to the broker." " Any further handling of ACKs for the packet Id" " will fail.", MQTT_Status_strerror( status ) ) ); } } if( status != MQTTSuccess ) { LogError( ( "MQTT PUBLISH failed with status %s.", MQTT_Status_strerror( status ) ) ); } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_Ping( MQTTContext_t * pContext ) { int32_t bytesSent = 0; MQTTStatus_t status = MQTTSuccess; size_t packetSize = 0U; if( pContext == NULL ) { LogError( ( "pContext is NULL." ) ); status = MQTTBadParameter; } if( status == MQTTSuccess ) { /* Get MQTT PINGREQ packet size. */ status = MQTT_GetPingreqPacketSize( &packetSize ); if( status == MQTTSuccess ) { LogDebug( ( "MQTT PINGREQ packet size is %lu.", ( unsigned long ) packetSize ) ); } else { LogError( ( "Failed to get the PINGREQ packet size." ) ); } } if( status == MQTTSuccess ) { /* Serialize MQTT PINGREQ. */ status = MQTT_SerializePingreq( &( pContext->networkBuffer ) ); } if( status == MQTTSuccess ) { /* Send the serialized PINGREQ packet to transport layer. */ bytesSent = sendPacket( pContext, pContext->networkBuffer.pBuffer, packetSize ); /* It is an error to not send the entire PINGREQ packet. */ if( bytesSent < 0 ) { LogError( ( "Transport send failed for PINGREQ packet." ) ); status = MQTTSendFailed; } else { pContext->pingReqSendTimeMs = pContext->lastPacketTime; pContext->waitingForPingResp = true; LogDebug( ( "Sent %d bytes of PINGREQ packet.", bytesSent ) ); } } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_Unsubscribe( MQTTContext_t * pContext, const MQTTSubscribeInfo_t * pSubscriptionList, size_t subscriptionCount, uint16_t packetId ) { size_t remainingLength = 0UL, packetSize = 0UL; int32_t bytesSent = 0; /* Validate arguments. */ MQTTStatus_t status = validateSubscribeUnsubscribeParams( pContext, pSubscriptionList, subscriptionCount, packetId ); if( status == MQTTSuccess ) { /* Get the remaining length and packet size.*/ status = MQTT_GetUnsubscribePacketSize( pSubscriptionList, subscriptionCount, &remainingLength, &packetSize ); LogDebug( ( "UNSUBSCRIBE packet size is %lu and remaining length is %lu.", ( unsigned long ) packetSize, ( unsigned long ) remainingLength ) ); } if( status == MQTTSuccess ) { /* Serialize MQTT UNSUBSCRIBE packet. */ status = MQTT_SerializeUnsubscribe( pSubscriptionList, subscriptionCount, packetId, remainingLength, &( pContext->networkBuffer ) ); } if( status == MQTTSuccess ) { /* Send serialized MQTT UNSUBSCRIBE packet to transport layer. */ bytesSent = sendPacket( pContext, pContext->networkBuffer.pBuffer, packetSize ); if( bytesSent < 0 ) { LogError( ( "Transport send failed for UNSUBSCRIBE packet." ) ); status = MQTTSendFailed; } else { LogDebug( ( "Sent %d bytes of UNSUBSCRIBE packet.", bytesSent ) ); } } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_Disconnect( MQTTContext_t * pContext ) { size_t packetSize = 0U; int32_t bytesSent = 0; MQTTStatus_t status = MQTTSuccess; /* Validate arguments. */ if( pContext == NULL ) { LogError( ( "pContext cannot be NULL." ) ); status = MQTTBadParameter; } if( status == MQTTSuccess ) { /* Get MQTT DISCONNECT packet size. */ status = MQTT_GetDisconnectPacketSize( &packetSize ); LogDebug( ( "MQTT DISCONNECT packet size is %lu.", ( unsigned long ) packetSize ) ); } if( status == MQTTSuccess ) { /* Serialize MQTT DISCONNECT packet. */ status = MQTT_SerializeDisconnect( &( pContext->networkBuffer ) ); } if( status == MQTTSuccess ) { bytesSent = sendPacket( pContext, pContext->networkBuffer.pBuffer, packetSize ); if( bytesSent < 0 ) { LogError( ( "Transport send failed for DISCONNECT packet." ) ); status = MQTTSendFailed; } else { LogDebug( ( "Sent %d bytes of DISCONNECT packet.", bytesSent ) ); } } if( status == MQTTSuccess ) { LogInfo( ( "Disconnected from the broker." ) ); pContext->connectStatus = MQTTNotConnected; } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_ProcessLoop( MQTTContext_t * pContext, uint32_t timeoutMs ) { MQTTStatus_t status = MQTTBadParameter; uint32_t entryTimeMs = 0U, remainingTimeMs = timeoutMs, elapsedTimeMs = 0U; if( pContext == NULL ) { LogError( ( "Invalid input parameter: MQTT Context cannot be NULL." ) ); } else if( pContext->getTime == NULL ) { LogError( ( "Invalid input parameter: MQTT Context must have valid getTime." ) ); } else if( pContext->networkBuffer.pBuffer == NULL ) { LogError( ( "Invalid input parameter: The MQTT context's networkBuffer must not be NULL." ) ); } else { entryTimeMs = pContext->getTime(); pContext->controlPacketSent = false; status = MQTTSuccess; } while( status == MQTTSuccess ) { status = receiveSingleIteration( pContext, remainingTimeMs, true ); /* We don't need to break here since the status is already checked in * the loop condition, and we do not want multiple breaks in a loop. */ if( status != MQTTSuccess ) { LogError( ( "Exiting process loop due to failure: ErrorStatus=%s", MQTT_Status_strerror( status ) ) ); } else { /* Recalculate remaining time and check if loop should exit. This is * done at the end so the loop will run at least a single iteration. */ elapsedTimeMs = calculateElapsedTime( pContext->getTime(), entryTimeMs ); if( elapsedTimeMs > timeoutMs ) { break; } remainingTimeMs = timeoutMs - elapsedTimeMs; } } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_ReceiveLoop( MQTTContext_t * pContext, uint32_t timeoutMs ) { MQTTStatus_t status = MQTTBadParameter; uint32_t entryTimeMs = 0U, remainingTimeMs = timeoutMs, elapsedTimeMs = 0U; if( pContext == NULL ) { LogError( ( "Invalid input parameter: MQTT Context cannot be NULL." ) ); } else if( pContext->getTime == NULL ) { LogError( ( "Invalid input parameter: MQTT Context must have a valid getTime function." ) ); } else if( pContext->networkBuffer.pBuffer == NULL ) { LogError( ( "Invalid input parameter: MQTT context's networkBuffer must not be NULL." ) ); } else { entryTimeMs = pContext->getTime(); status = MQTTSuccess; } while( status == MQTTSuccess ) { status = receiveSingleIteration( pContext, remainingTimeMs, false ); /* We don't need to break here since the status is already checked in * the loop condition, and we do not want multiple breaks in a loop. */ if( status != MQTTSuccess ) { LogError( ( "Exiting receive loop. Error status=%s", MQTT_Status_strerror( status ) ) ); } else { /* Recalculate remaining time and check if loop should exit. This is * done at the end so the loop will run at least a single iteration. */ elapsedTimeMs = calculateElapsedTime( pContext->getTime(), entryTimeMs ); if( elapsedTimeMs >= timeoutMs ) { break; } remainingTimeMs = timeoutMs - elapsedTimeMs; } } return status; } /*-----------------------------------------------------------*/ uint16_t MQTT_GetPacketId( MQTTContext_t * pContext ) { uint16_t packetId = 0U; if( pContext != NULL ) { packetId = pContext->nextPacketId; /* A packet ID of zero is not a valid packet ID. When the max ID * is reached the next one should start at 1. */ if( pContext->nextPacketId == ( uint16_t ) UINT16_MAX ) { pContext->nextPacketId = 1; } else { pContext->nextPacketId++; } } return packetId; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_MatchTopic( const char * pTopicName, const uint16_t topicNameLength, const char * pTopicFilter, const uint16_t topicFilterLength, bool * pIsMatch ) { MQTTStatus_t status = MQTTSuccess; bool topicFilterStartsWithWildcard = false; bool matchStatus = false; if( ( pTopicName == NULL ) || ( topicNameLength == 0u ) ) { LogError( ( "Invalid paramater: Topic name should be non-NULL and its " "length should be > 0: TopicName=%p, TopicNameLength=%u", ( void * ) pTopicName, topicNameLength ) ); status = MQTTBadParameter; } else if( ( pTopicFilter == NULL ) || ( topicFilterLength == 0u ) ) { LogError( ( "Invalid paramater: Topic filter should be non-NULL and " "its length should be > 0: TopicName=%p, TopicFilterLength=%u", ( void * ) pTopicFilter, topicFilterLength ) ); status = MQTTBadParameter; } else if( pIsMatch == NULL ) { LogError( ( "Invalid paramater: Output parameter, pIsMatch, is NULL" ) ); status = MQTTBadParameter; } else { /* Check for an exact match if the incoming topic name and the registered * topic filter length match. */ if( topicNameLength == topicFilterLength ) { matchStatus = ( strncmp( pTopicName, pTopicFilter, topicNameLength ) == 0 ) ? true : false; } if( matchStatus == false ) { /* If an exact match was not found, match against wildcard characters in * topic filter.*/ /* Determine if topic filter starts with a wildcard. */ topicFilterStartsWithWildcard = ( ( pTopicFilter[ 0 ] == '+' ) || ( pTopicFilter[ 0 ] == '#' ) ) ? true : false; /* Note: According to the MQTT 3.1.1 specification, incoming PUBLISH topic names * starting with "$" character cannot be matched against topic filter starting with * a wildcard, i.e. for example, "$SYS/sport" cannot be matched with "#" or * "+/sport" topic filters. */ if( !( ( pTopicName[ 0 ] == '$' ) && ( topicFilterStartsWithWildcard == true ) ) ) { matchStatus = matchTopicFilter( pTopicName, topicNameLength, pTopicFilter, topicFilterLength ); } } /* Update the output parameter with the match result. */ *pIsMatch = matchStatus; } return status; } /*-----------------------------------------------------------*/ MQTTStatus_t MQTT_GetSubAckStatusCodes( const MQTTPacketInfo_t * pSubackPacket, uint8_t ** pPayloadStart, size_t * pPayloadSize ) { MQTTStatus_t status = MQTTSuccess; if( pSubackPacket == NULL ) { LogError( ( "Invalid parameter: pSubackPacket is NULL." ) ); status = MQTTBadParameter; } else if( pPayloadStart == NULL ) { LogError( ( "Invalid parameter: pPayloadStart is NULL." ) ); status = MQTTBadParameter; } else if( pPayloadSize == NULL ) { LogError( ( "Invalid parameter: pPayloadSize is NULL." ) ); status = MQTTBadParameter; } else if( pSubackPacket->type != MQTT_PACKET_TYPE_SUBACK ) { LogError( ( "Invalid parameter: Input packet is not a SUBACK packet: " "ExpectedType=%02x, InputType=%02x", MQTT_PACKET_TYPE_SUBACK, pSubackPacket->type ) ); status = MQTTBadParameter; } else if( pSubackPacket->pRemainingData == NULL ) { LogError( ( "Invalid parameter: pSubackPacket->pRemainingData is NULL" ) ); status = MQTTBadParameter; } /* A SUBACK must have a remaining length of at least 3 to accommodate the * packet identifier and at least 1 return code. */ else if( pSubackPacket->remainingLength < 3U ) { LogError( ( "Invalid parameter: Packet remaining length is invalid: " "Should be greater than 2 for SUBACK packet: InputRemainingLength=%lu", ( unsigned long ) pSubackPacket->remainingLength ) ); status = MQTTBadParameter; } else { /* According to the MQTT 3.1.1 protocol specification, the "Remaining Length" field is a * length of the variable header (2 bytes) plus the length of the payload. * Therefore, we add 2 positions for the starting address of the payload, and * subtract 2 bytes from the remaining length for the length of the payload.*/ *pPayloadStart = pSubackPacket->pRemainingData + ( ( uint16_t ) sizeof( uint16_t ) ); *pPayloadSize = pSubackPacket->remainingLength - sizeof( uint16_t ); } return status; } /*-----------------------------------------------------------*/ const char * MQTT_Status_strerror( MQTTStatus_t status ) { const char * str = NULL; switch( status ) { case MQTTSuccess: str = "MQTTSuccess"; break; case MQTTBadParameter: str = "MQTTBadParameter"; break; case MQTTNoMemory: str = "MQTTNoMemory"; break; case MQTTSendFailed: str = "MQTTSendFailed"; break; case MQTTRecvFailed: str = "MQTTRecvFailed"; break; case MQTTBadResponse: str = "MQTTBadResponse"; break; case MQTTServerRefused: str = "MQTTServerRefused"; break; case MQTTNoDataAvailable: str = "MQTTNoDataAvailable"; break; case MQTTIllegalState: str = "MQTTIllegalState"; break; case MQTTStateCollision: str = "MQTTStateCollision"; break; case MQTTKeepAliveTimeout: str = "MQTTKeepAliveTimeout"; break; case MQTTNotAuthorized: str = "Connection not authorized"; break; default: str = "Invalid MQTT Status code"; break; } return str; } /*-----------------------------------------------------------*/