/**
* @brief Subscribe to an MQTT topic.
*
* Called to send a subscribe message to the broker requesting a subscription
* to an MQTT topic.
* This is the internal function which is called by the resubscribe API to perform the operation.
* Not meant to be called directly as it doesn't do validations or client state changes
* @note Call is blocking. The call returns after the receipt of the SUBACK control packet.
*
* @param pClient Reference to the IoT Client
*
* @return An IoT Error Type defining successful/failed subscription
*/
static IoT_Error_t _aws_iot_mqtt_internal_resubscribe(AWS_IoT_Client *pClient) {
uint16_t packetId;
uint32_t len, count, existingSubCount, itr;
IoT_Error_t rc;
Timer timer;
QoS grantedQoS[3] = {QOS0, QOS0, QOS0};
FUNC_ENTRY;
packetId = 0;
len = 0;
count = 0;
existingSubCount = _aws_iot_mqtt_get_free_message_handler_index(pClient);
for(itr = 0; itr < existingSubCount; itr++) {
init_timer(&timer);
countdown_ms(&timer, pClient->clientData.commandTimeoutMs);
rc = _aws_iot_mqtt_serialize_subscribe(pClient->clientData.writeBuf, pClient->clientData.writeBufSize, 0,
aws_iot_mqtt_get_next_packet_id(pClient), 1,
&(pClient->clientData.messageHandlers[itr].topicName),
&(pClient->clientData.messageHandlers[itr].topicNameLen),
&(pClient->clientData.messageHandlers[itr].qos), &len);
if(AWS_SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
/* send the subscribe packet */
rc = aws_iot_mqtt_internal_send_packet(pClient, len, &timer);
if(AWS_SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
/* wait for suback */
rc = aws_iot_mqtt_internal_wait_for_read(pClient, SUBACK, &timer);
if(AWS_SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
/* Granted QoS can be 0, 1 or 2 */
rc = _aws_iot_mqtt_deserialize_suback(&packetId, 1, &count, grantedQoS, pClient->clientData.readBuf,
pClient->clientData.readBufSize);
if(AWS_SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
}
FUNC_EXIT_RC(AWS_SUCCESS);
}
/**
* @brief MQTT Connection Function
*
* Called to establish an MQTT connection with the AWS IoT Service
* This is the internal function which is called by the connect API to perform the operation.
* Not meant to be called directly as it doesn't do validations or client state changes
*
* @param pClient Reference to the IoT Client
* @param pConnectParams Pointer to MQTT connection parameters
*
* @return An IoT Error Type defining successful/failed connection
*/
static IoT_Error_t _aws_iot_mqtt_internal_connect(AWS_IoT_Client *pClient, IoT_Client_Connect_Params *pConnectParams) {
Timer connect_timer;
IoT_Error_t connack_rc = FAILURE;
char sessionPresent = 0;
size_t len = 0;
IoT_Error_t rc = FAILURE;
FUNC_ENTRY;
if(NULL != pConnectParams) {
/* override default options if new options were supplied */
rc = aws_iot_mqtt_set_connect_params(pClient, pConnectParams);
if(SUCCESS != rc) {
FUNC_EXIT_RC(MQTT_CONNECTION_ERROR);
}
}
rc = pClient->networkStack.connect(&(pClient->networkStack), NULL);
if(SUCCESS != rc) {
/* TLS Connect failed, return error */
FUNC_EXIT_RC(rc);
}
init_timer(&connect_timer);
countdown_ms(&connect_timer, pClient->clientData.commandTimeoutMs);
pClient->clientData.keepAliveInterval = pClient->clientData.options.keepAliveIntervalInSec;
rc = _aws_iot_mqtt_serialize_connect(pClient->clientData.writeBuf, pClient->clientData.writeBufSize,
&(pClient->clientData.options), &len);
if(SUCCESS != rc || 0 >= len) {
FUNC_EXIT_RC(rc);
}
/* send the connect packet */
rc = aws_iot_mqtt_internal_send_packet(pClient, len, &connect_timer);
if(SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
/* this will be a blocking call, wait for the CONNACK */
rc = aws_iot_mqtt_internal_wait_for_read(pClient, CONNACK, &connect_timer);
if(SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
/* Received CONNACK, check the return code */
rc = _aws_iot_mqtt_deserialize_connack((unsigned char *) &sessionPresent, &connack_rc, pClient->clientData.readBuf,
pClient->clientData.readBufSize);
if(SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
if(MQTT_CONNACK_CONNECTION_ACCEPTED != connack_rc) {
FUNC_EXIT_RC(connack_rc);
}
pClient->clientStatus.isPingOutstanding = false;
countdown_sec(&pClient->pingTimer, pClient->clientData.keepAliveInterval);
FUNC_EXIT_RC(SUCCESS);
}
/**
* @brief Subscribe to an MQTT topic.
*
* Called to send a subscribe message to the broker requesting a subscription
* to an MQTT topic. This is the internal function which is called by the
* subscribe API to perform the operation. Not meant to be called directly as
* it doesn't do validations or client state changes
* @note Call is blocking. The call returns after the receipt of the SUBACK control packet.
*
* @param pClient Reference to the IoT Client
* @param pTopicName Topic Name to publish to
* @param topicNameLen Length of the topic name
* @param pApplicationHandler_t Reference to the handler function for this subscription
*
* @return An IoT Error Type defining successful/failed subscription
*/
static IoT_Error_t _aws_iot_mqtt_internal_subscribe(AWS_IoT_Client *pClient, const char *pTopicName,
uint16_t topicNameLen, QoS qos,
pApplicationHandler_t pApplicationHandler,
void *pApplicationHandlerData) {
uint16_t txPacketId, rxPacketId;
uint32_t serializedLen, indexOfFreeMessageHandler, count;
IoT_Error_t rc;
Timer timer;
QoS grantedQoS[3] = {QOS0, QOS0, QOS0};
FUNC_ENTRY;
init_timer(&timer);
countdown_ms(&timer, pClient->clientData.commandTimeoutMs);
serializedLen = 0;
count = 0;
txPacketId = aws_iot_mqtt_get_next_packet_id(pClient);
rxPacketId = 0;
rc = _aws_iot_mqtt_serialize_subscribe(pClient->clientData.writeBuf, pClient->clientData.writeBufSize, 0,
txPacketId, 1, &pTopicName, &topicNameLen, &qos, &serializedLen);
if(AWS_SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
indexOfFreeMessageHandler = _aws_iot_mqtt_get_free_message_handler_index(pClient);
if(AWS_IOT_MQTT_NUM_SUBSCRIBE_HANDLERS <= indexOfFreeMessageHandler) {
FUNC_EXIT_RC(MQTT_MAX_SUBSCRIPTIONS_REACHED_ERROR);
}
/* send the subscribe packet */
rc = aws_iot_mqtt_internal_send_packet(pClient, serializedLen, &timer);
if(AWS_SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
/* wait for suback */
rc = aws_iot_mqtt_internal_wait_for_read(pClient, SUBACK, &timer);
if(AWS_SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
/* Granted QoS can be 0, 1 or 2 */
rc = _aws_iot_mqtt_deserialize_suback(&rxPacketId, 1, &count, grantedQoS, pClient->clientData.readBuf,
pClient->clientData.readBufSize);
if(AWS_SUCCESS != rc) {
FUNC_EXIT_RC(rc);
}
/* TODO : Figure out how to test this before activating this check */
//if(txPacketId != rxPacketId) {
/* Different SUBACK received than expected. Return error
* This can cause issues if the request timeout value is too small */
// return RX_MESSAGE_INVALID_ERROR;
//}
pClient->clientData.messageHandlers[indexOfFreeMessageHandler].topicName =
pTopicName;
pClient->clientData.messageHandlers[indexOfFreeMessageHandler].topicNameLen =
topicNameLen;
pClient->clientData.messageHandlers[indexOfFreeMessageHandler].pApplicationHandler =
pApplicationHandler;
pClient->clientData.messageHandlers[indexOfFreeMessageHandler].pApplicationHandlerData =
pApplicationHandlerData;
pClient->clientData.messageHandlers[indexOfFreeMessageHandler].qos = qos;
FUNC_EXIT_RC(AWS_SUCCESS);
}
