Hi, I am currently using the NRF52840 DK and trying to connect, Pub and Sub to AWS iot. I am using an external modem with an AT interface. The modem has 4G LTE capabilities with an IP stack. I have successfully developed an AT driver which can communicate with the modem. I can send an AT command to open a transparent connection with AWS broker. However, I am now struggling to generate a connect packet using "_IotMqtt_SerializeConnect" function. My aim is to generate a connect packet and as then send it using AT command to connect to AWS.

I have made sure to include the cA PEM broker certificate and the public and private client certificates as I am trying to establish a secure SSL connection with the broker. I also included the broker endpoint and port number and several other connection profile details as shown below in my code.
Currently I am getting a hard system error with id = 0x00004002. Below is a snippet of my code. I relied heavily on FreeRtos example code.

Many thanks in advance

CODE :

static const struct IotNetworkServerInfo xMQTTBrokerInfo = { .pHostName = clientcredentialMQTT_BROKER_ENDPOINT, .port = clientcredentialMQTT_BROKER_PORT };

static struct IotNetworkCredentials xNetworkSecurityCredentials = { / Optional TLS extensions. For this demo, they are disabled. / .pAlpnProtos = NULL, .maxFragmentLength = 0,

/ SNI is enabled by default. / .disableSni = false,

/* Provide the certificate for validating the server. Only required for

demos using TLS. */ .pRootCa = mqttBROKER_CERTIFICATE_PEM, .rootCaSize = sizeof( mqttBROKER_CERTIFICATE_PEM ),

/* Strong mutual authentication to authenticate both the broker and
the client. */ .pClientCert = keyCLIENT_CERTIFICATE_PEM , .clientCertSize = sizeof(keyCLIENT_CERTIFICATE_PEM), .pPrivateKey = keyCLIENT_PRIVATE_KEY_PEM, .privateKeySize = sizeof(keyCLIENT_PRIVATE_KEY_PEM) }; void prvExample_OnDisconnect(){

while(1){ printf("DISCONNEECTED"); }

} static IotMqttNetworkInfo_t xNetworkInfo = { /* No connection to the MQTT broker has been established yet and we want to

establish a new connection. */ .createNetworkConnection = true, .u.setup.pNetworkServerInfo = &( xMQTTBrokerInfo ),

/* Set the TLS credentials for the new MQTT connection. This member is NULL
for the plain text MQTT demo. */ .u.setup.pNetworkCredentialInfo = &xNetworkSecurityCredentials,

/ Use FreeRTOS+TCP network interface. / .pNetworkInterface = AWSIOT_NETWORK_TYPE_TCP_IP,

/* Setup the callback which is called when the MQTT connection is
disconnected. The task handle is passed as the callback context which
is used by the callback to send a task notification to this task.*/ .disconnectCallback.function = prvExample_OnDisconnect };

define mqttexampleCLIENT_IDENTIFIER "nrf52840"

static const IotMqttConnectInfo_t xConnectInfo = { / Set this flag to true if connecting to the AWS IoT MQTT broker. / .awsIotMqttMode = true,

/* Start with a clean session i.e. direct the MQTT broker to discard any

previous session data. Also, establishing a connection with clean session
will ensure that the broker does not store any data when this client
gets disconnected. */ .cleanSession = true,

/* Since we are starting with a clean session, there are no previous
subscriptions to be restored. */ .pPreviousSubscriptions = NULL, .previousSubscriptionCount = 0,

/* We do not want to publish Last Will and Testament (LWT) message if the
client gets disconnected. */ .pWillInfo = NULL,

/ Send an MQTT PING request every minute to keep the connection open if there is no other MQTT traffic. / .keepAliveSeconds = 1000,

/* The client identifier is used to uniquely identify this MQTT client to
the MQTT broker. In a production device the identifier can be something
unique, such as a device serial number. */ .pClientIdentifier = mqttexampleCLIENT_IDENTIFIER, .clientIdentifierLength = ( uint16_t ) sizeof( mqttexampleCLIENT_IDENTIFIER ) - 1,

/* This example does not authenticate the client and therefore username and
password fields are not used. */ .pUserName = NULL, .userNameLength = 0, .pPassword = NULL, .passwordLength = 0 };

//void vMQTTTask( void * pvParameters ) void vMQTTTask() {

IotMqttError_t xResult; size_t xRemainingLength; size_t * xPacketSize; // IotMqttPacketInfo_t xIncomingPacket; BaseType_t xStatus; uint8_t * ConnectPacket; / Set the context to pass into the disconnect callback function. / xNetworkInfo.disconnectCallback.pCallbackContext = ( void ) xTaskGetCurrentTaskHandle(); IotMqttConnection_t mqttConnection = IOT_MQTT_CONNECTION_INITIALIZER; /* Establish the connection to the MQTT broker - It is a blocking call and
will return only when connection is complete or a timeout occurs. The
network and connection structures are declared and initialised at the top
of this file. / // xResult = IotMqtt_Connect( &( xNetworkInfo ), // &( xConnectInfo ), // 6000, // &( mqttConnection ) ); //
// // configASSERT( xResult == IOT_MQTT_SUCCESS ); // SOCKETS_Socket(); // create a socket - function found in iot_secure_sockets.h / Get size requirement for the connect packet */

// xResult = IotMqtt_GetConnectPacketSize( &xConnectInfo, // &xRemainingLength, // &xPacketSize );

/* Make sure the packet size is less than static buffer size. */
//configASSERT( xResult == IOT_MQTT_SUCCESS );
//configASSERT( xPacketSize < mqttexampleSHARED_BUFFER_SIZE );

/* Serialize MQTT connect packet into the provided buffer. */
xResult = _IotMqtt_SerializeConnect( &xConnectInfo,
                                         ConnectPacket,
                                         xPacketSize );

configASSERT( xResult == IOT_MQTT_SUCCESS );

// for( ;; ) // { // // Task code goes here. // // // At some point we want to end the real time kernel processing // // so call ... //vTaskEndScheduler (); // } }

void MQTT_CONNECT( void ) { // Create at least one task before starting the kernel. // xTaskCreate( vMQTTTask, "MQTT_TASK", 4500, NULL, 1, NULL );

 // Start the real time kernel with preemption.
// vTaskStartScheduler ();

 // Will not get here unless a task calls vTaskEndScheduler ()
     //vTaskEndScheduler ();

}

int main( void ) { /* Perform any hardware initialization that does not require the RTOS to be

running. */ prvMiscInitialization();

xLoggingTaskInitialize( mainLOGGING_TASK_STACK_SIZE, tskIDLE_PRIORITY, mainLOGGING_MESSAGE_QUEUE_LENGTH );

nrf_sdh_freertos_init( NULL, NULL ); ret_code_t xErrCode = pm_init();

printf("\nSTART main\n");

init_serial();

init_modem(); //MQTT_CONNECT(); vMQTTTask(); printf("\nEND");

//vTaskStartScheduler(); return 0; }

aws / amazon-freertos

Problem with generating connect packet using "_IotMqtt_SerializeConnect" #1870

define mqttexampleCLIENT_IDENTIFIER "nrf52840"