Diff: aws-iot/src/aws_iot_mqtt_client_connect.cpp

Revision:

0:cd5404401c2f

diff -r 000000000000 -r cd5404401c2f aws-iot/src/aws_iot_mqtt_client_connect.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/aws-iot/src/aws_iot_mqtt_client_connect.cpp	Wed Apr 12 14:07:09 2017 +0200
@@ -0,0 +1,621 @@
+/*
+* Copyright 2015-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+*
+* Licensed under the Apache License, Version 2.0 (the "License").
+* You may not use this file except in compliance with the License.
+* A copy of the License is located at
+*
+* http://aws.amazon.com/apache2.0
+*
+* or in the "license" file accompanying this file. This file is distributed
+* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+* express or implied. See the License for the specific language governing
+* permissions and limitations under the License.
+*/
+
+// Based on Eclipse Paho.
+/*******************************************************************************
+ * Copyright (c) 2014 IBM Corp.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * and Eclipse Distribution License v1.0 which accompany this distribution.
+ *
+ * The Eclipse Public License is available at
+ *    http://www.eclipse.org/legal/epl-v10.html
+ * and the Eclipse Distribution License is available at
+ *   http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * Contributors:
+ *    Ian Craggs - initial API and implementation and/or initial documentation
+ *******************************************************************************/
+
+/**
+ * @file aws_iot_mqtt_client_connect.c
+ * @brief MQTT client connect API definition and related functions
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <aws_iot_mqtt_client.h>
+#include "aws_iot_mqtt_client_interface.h"
+#include "aws_iot_mqtt_client_common_internal.h"
+
+typedef union {
+	uint8_t all;    /**< all connect flags */
+#if defined(REVERSED)
+	struct
+	{
+		unsigned int username : 1;		/**< 3.1 user name */
+		unsigned int password : 1;		/**< 3.1 password */
+		unsigned int willRetain : 1;	/**< will retain setting */
+		unsigned int willQoS : 2;		/**< will QoS value */
+		unsigned int will : 1;			/**< will flag */
+		unsigned int cleansession : 1;	/**< clean session flag */
+		unsigned int : 1;				/**< unused */
+	} bits;
+#else
+	struct {
+		unsigned int : 1;
+		/**< unused */
+		unsigned int cleansession : 1;
+		/**< cleansession flag */
+		unsigned int will : 1;
+		/**< will flag */
+		unsigned int willQoS : 2;
+		/**< will QoS value */
+		unsigned int willRetain : 1;
+		/**< will retain setting */
+		unsigned int password : 1;
+		/**< 3.1 password */
+		unsigned int username : 1;        /**< 3.1 user name */
+	} bits;
+#endif
+} MQTT_Connect_Header_Flags;
+/**< connect flags byte */
+
+typedef union {
+	uint8_t all;                            /**< all connack flags */
+#if defined(REVERSED)
+	struct
+	{
+		unsigned int sessionpresent : 1;	/**< session present flag */
+		unsigned int : 7;					/**< unused */
+	} bits;
+#else
+	struct {
+		unsigned int : 7;
+		/**< unused */
+		unsigned int sessionpresent : 1;    /**< session present flag */
+	} bits;
+#endif
+} MQTT_Connack_Header_Flags;
+/**< connack flags byte */
+
+typedef enum {
+	CONNACK_CONNECTION_ACCEPTED = 0,
+	CONNACK_UNACCEPTABLE_PROTOCOL_VERSION_ERROR = 1,
+	CONNACK_IDENTIFIER_REJECTED_ERROR = 2,
+	CONNACK_SERVER_UNAVAILABLE_ERROR = 3,
+	CONNACK_BAD_USERDATA_ERROR = 4,
+	CONNACK_NOT_AUTHORIZED_ERROR = 5
+} MQTT_Connack_Return_Codes;    /**< Connect request response codes from server */
+
+
+/**
+  * Determines the length of the MQTT connect packet that would be produced using the supplied connect options.
+  * @param options the options to be used to build the connect packet
+  * @param the length of buffer needed to contain the serialized version of the packet
+  * @return IoT_Error_t indicating function execution status
+  */
+static uint32_t _aws_iot_get_connect_packet_length(IoT_Client_Connect_Params *pConnectParams) {
+	uint32_t len;
+	/* Enable when adding further MQTT versions */
+	/*size_t len = 0;
+	switch(pConnectParams->MQTTVersion) {
+		case MQTT_3_1_1:
+			len = 10;
+			break;
+	}*/
+	FUNC_ENTRY;
+
+	len = 10; // Len = 10 for MQTT_3_1_1
+	len = len + pConnectParams->clientIDLen + 2;
+
+	if(pConnectParams->isWillMsgPresent) {
+		len = len + pConnectParams->will.topicNameLen + 2 + pConnectParams->will.msgLen + 2;
+	}
+
+	if(NULL != pConnectParams->pUsername) {
+		len = len + pConnectParams->usernameLen + 2;
+	}
+
+	if(NULL != pConnectParams->pPassword) {
+		len = len + pConnectParams->passwordLen + 2;
+	}
+
+	FUNC_EXIT_RC(len);
+}
+
+/**
+  * Serializes the connect options into the buffer.
+  * @param buf the buffer into which the packet will be serialized
+  * @param len the length in bytes of the supplied buffer
+  * @param options the options to be used to build the connect packet
+  * @param serialized length
+  * @return IoT_Error_t indicating function execution status
+  */
+static IoT_Error_t _aws_iot_mqtt_serialize_connect(unsigned char *pTxBuf, size_t txBufLen,
+												   IoT_Client_Connect_Params *pConnectParams,
+												   size_t *pSerializedLen) {
+	unsigned char *ptr;
+	uint32_t len;
+	IoT_Error_t rc;
+	MQTTHeader header = {0};
+	MQTT_Connect_Header_Flags flags = {0};
+
+	FUNC_ENTRY;
+
+	if(NULL == pTxBuf || NULL == pConnectParams || NULL == pSerializedLen ||
+	   (NULL == pConnectParams->pClientID && 0 != pConnectParams->clientIDLen) ||
+	   (NULL != pConnectParams->pClientID && 0 == pConnectParams->clientIDLen)) {
+		FUNC_EXIT_RC(NULL_VALUE_ERROR);
+	}
+
+	/* Check needed here before we start writing to the Tx buffer */
+	switch(pConnectParams->MQTTVersion) {
+		case MQTT_3_1_1:
+			break;
+		default:
+			return MQTT_CONNACK_UNACCEPTABLE_PROTOCOL_VERSION_ERROR;
+	}
+
+	ptr = pTxBuf;
+	len = _aws_iot_get_connect_packet_length(pConnectParams);
+	if(aws_iot_mqtt_internal_get_final_packet_length_from_remaining_length(len) > txBufLen) {
+		FUNC_EXIT_RC(MQTT_TX_BUFFER_TOO_SHORT_ERROR);
+	}
+
+	rc = aws_iot_mqtt_internal_init_header(&header, CONNECT, QOS0, 0, 0);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+
+	aws_iot_mqtt_internal_write_char(&ptr, header.byte); /* write header */
+
+	ptr += aws_iot_mqtt_internal_write_len_to_buffer(ptr, len); /* write remaining length */
+
+	// Enable if adding support for more versions
+	//if(MQTT_3_1_1 == pConnectParams->MQTTVersion) {
+	aws_iot_mqtt_internal_write_utf8_string(&ptr, "MQTT", 4);
+	aws_iot_mqtt_internal_write_char(&ptr, (unsigned char) pConnectParams->MQTTVersion);
+	//}
+
+	flags.all = 0;
+	flags.bits.cleansession = (pConnectParams->isCleanSession) ? 1 : 0;
+	flags.bits.will = (pConnectParams->isWillMsgPresent) ? 1 : 0;
+	if(flags.bits.will) {
+		flags.bits.willQoS = pConnectParams->will.qos;
+		flags.bits.willRetain = (pConnectParams->will.isRetained) ? 1 : 0;
+	}
+
+	if(pConnectParams->pUsername) {
+		flags.bits.username = 1;
+	}
+
+	if(pConnectParams->pPassword) {
+		flags.bits.password = 1;
+	}
+
+	aws_iot_mqtt_internal_write_char(&ptr, flags.all);
+	aws_iot_mqtt_internal_write_uint_16(&ptr, pConnectParams->keepAliveIntervalInSec);
+
+	/* If the code have passed the check for incorrect values above, no client id was passed as argument */
+	if(NULL == pConnectParams->pClientID) {
+		aws_iot_mqtt_internal_write_uint_16(&ptr, 0);
+	} else {
+		aws_iot_mqtt_internal_write_utf8_string(&ptr, pConnectParams->pClientID, pConnectParams->clientIDLen);
+	}
+
+	if(pConnectParams->isWillMsgPresent) {
+		aws_iot_mqtt_internal_write_utf8_string(&ptr, pConnectParams->will.pTopicName,
+												pConnectParams->will.topicNameLen);
+		aws_iot_mqtt_internal_write_utf8_string(&ptr, pConnectParams->will.pMessage, pConnectParams->will.msgLen);
+	}
+
+	if(flags.bits.username) {
+		aws_iot_mqtt_internal_write_utf8_string(&ptr, pConnectParams->pUsername, pConnectParams->usernameLen);
+	}
+
+	if(flags.bits.password) {
+		aws_iot_mqtt_internal_write_utf8_string(&ptr, pConnectParams->pPassword, pConnectParams->passwordLen);
+	}
+
+	*pSerializedLen = (size_t) (ptr - pTxBuf);
+
+	FUNC_EXIT_RC(SUCCESS);
+}
+
+/**
+  * Deserializes the supplied (wire) buffer into connack data - return code
+  * @param sessionPresent the session present flag returned (only for MQTT 3.1.1)
+  * @param connack_rc returned integer value of the connack return code
+  * @param buf the raw buffer data, of the correct length determined by the remaining length field
+  * @param buflen the length in bytes of the data in the supplied buffer
+  * @return IoT_Error_t indicating function execution status
+  */
+static IoT_Error_t _aws_iot_mqtt_deserialize_connack(unsigned char *pSessionPresent, IoT_Error_t *pConnackRc,
+													 unsigned char *pRxBuf, size_t rxBufLen) {
+	unsigned char *curdata, *enddata;
+	unsigned char connack_rc_char;
+	uint32_t decodedLen, readBytesLen;
+	IoT_Error_t rc;
+	MQTT_Connack_Header_Flags flags = {0};
+	MQTTHeader header = {0};
+
+	FUNC_ENTRY;
+
+	if(NULL == pSessionPresent || NULL == pConnackRc || NULL == pRxBuf) {
+		FUNC_EXIT_RC(NULL_VALUE_ERROR);
+	}
+
+	/* CONNACK header size is fixed at two bytes for fixed and 2 bytes for variable,
+	 * using that as minimum size
+	 * MQTT v3.1.1 Specification 3.2.1 */
+	if(4 > rxBufLen) {
+		FUNC_EXIT_RC(MQTT_RX_BUFFER_TOO_SHORT_ERROR);
+	}
+
+	curdata = pRxBuf;
+	enddata = NULL;
+	decodedLen = 0;
+	readBytesLen = 0;
+
+	header.byte = aws_iot_mqtt_internal_read_char(&curdata);
+	if(CONNACK != header.bits.type) {
+		FUNC_EXIT_RC(FAILURE);
+	}
+
+	/* read remaining length */
+	rc = aws_iot_mqtt_internal_decode_remaining_length_from_buffer(curdata, &decodedLen, &readBytesLen);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+
+	/* CONNACK remaining length should always be 2 as per MQTT 3.1.1 spec */
+	curdata += (readBytesLen);
+	enddata = curdata + decodedLen;
+	if(2 != (enddata - curdata)) {
+		FUNC_EXIT_RC(MQTT_DECODE_REMAINING_LENGTH_ERROR);
+	}
+
+	flags.all = aws_iot_mqtt_internal_read_char(&curdata);
+	*pSessionPresent = flags.bits.sessionpresent;
+	connack_rc_char = aws_iot_mqtt_internal_read_char(&curdata);
+	switch(connack_rc_char) {
+		case CONNACK_CONNECTION_ACCEPTED:
+			*pConnackRc = MQTT_CONNACK_CONNECTION_ACCEPTED;
+			break;
+		case CONNACK_UNACCEPTABLE_PROTOCOL_VERSION_ERROR:
+			*pConnackRc = MQTT_CONNACK_UNACCEPTABLE_PROTOCOL_VERSION_ERROR;
+			break;
+		case CONNACK_IDENTIFIER_REJECTED_ERROR:
+			*pConnackRc = MQTT_CONNACK_IDENTIFIER_REJECTED_ERROR;
+			break;
+		case CONNACK_SERVER_UNAVAILABLE_ERROR:
+			*pConnackRc = MQTT_CONNACK_SERVER_UNAVAILABLE_ERROR;
+			break;
+		case CONNACK_BAD_USERDATA_ERROR:
+			*pConnackRc = MQTT_CONNACK_BAD_USERDATA_ERROR;
+			break;
+		case CONNACK_NOT_AUTHORIZED_ERROR:
+			*pConnackRc = MQTT_CONNACK_NOT_AUTHORIZED_ERROR;
+			break;
+		default:
+			*pConnackRc = MQTT_CONNACK_UNKNOWN_ERROR;
+			break;
+	}
+
+	FUNC_EXIT_RC(SUCCESS);
+}
+
+/**
+ * @brief Check if client state is valid for a connect request
+ *
+ * Called to check if client state is valid for a connect request
+ * @param pClient Reference to the IoT Client
+ *
+ * @return bool true = state is valid, false = not valid
+ */
+static bool _aws_iot_mqtt_is_client_state_valid_for_connect(ClientState clientState) {
+	bool isValid = false;
+
+	switch(clientState) {
+		case CLIENT_STATE_INVALID:
+			isValid = false;
+			break;
+		case CLIENT_STATE_INITIALIZED:
+			isValid = true;
+			break;
+		case CLIENT_STATE_CONNECTING:
+		case CLIENT_STATE_CONNECTED_IDLE:
+		case CLIENT_STATE_CONNECTED_YIELD_IN_PROGRESS:
+		case CLIENT_STATE_CONNECTED_PUBLISH_IN_PROGRESS:
+		case CLIENT_STATE_CONNECTED_SUBSCRIBE_IN_PROGRESS:
+		case CLIENT_STATE_CONNECTED_UNSUBSCRIBE_IN_PROGRESS:
+		case CLIENT_STATE_CONNECTED_RESUBSCRIBE_IN_PROGRESS:
+		case CLIENT_STATE_CONNECTED_WAIT_FOR_CB_RETURN:
+		case CLIENT_STATE_DISCONNECTING:
+			isValid = false;
+			break;
+		case CLIENT_STATE_DISCONNECTED_ERROR:
+		case CLIENT_STATE_DISCONNECTED_MANUALLY:
+		case CLIENT_STATE_PENDING_RECONNECT:
+			isValid = true;
+			break;
+		default:
+			break;
+	}
+
+	return isValid;
+}
+
+/**
+ * @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) {
+	TimerAWS 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 MQTT Connection Function
+ *
+ * Called to establish an MQTT connection with the AWS IoT Service
+ * This is the outer function which does the validations and calls the internal connect above
+ * to perform the actual operation. It is also responsible for 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
+ */
+IoT_Error_t aws_iot_mqtt_connect(AWS_IoT_Client *pClient, IoT_Client_Connect_Params *pConnectParams) {
+	IoT_Error_t rc, disconRc;
+	ClientState clientState;
+
+	FUNC_ENTRY;
+
+	if(NULL == pClient) {
+		FUNC_EXIT_RC(NULL_VALUE_ERROR);
+	}
+
+	clientState = aws_iot_mqtt_get_client_state(pClient);
+
+	if(false == _aws_iot_mqtt_is_client_state_valid_for_connect(clientState)) {
+		/* Don't send connect packet again if we are already connected
+		 * or in the process of connecting/disconnecting */
+		FUNC_EXIT_RC(NETWORK_ALREADY_CONNECTED_ERROR);
+	}
+
+	aws_iot_mqtt_set_client_state(pClient, clientState, CLIENT_STATE_CONNECTING);
+
+	rc = _aws_iot_mqtt_internal_connect(pClient, pConnectParams);
+
+	if(SUCCESS != rc) {
+		pClient->networkStack.disconnect(&(pClient->networkStack));
+		disconRc = pClient->networkStack.destroy(&(pClient->networkStack));
+		aws_iot_mqtt_set_client_state(pClient, CLIENT_STATE_CONNECTING, CLIENT_STATE_DISCONNECTED_ERROR);
+	} else {
+		aws_iot_mqtt_set_client_state(pClient, CLIENT_STATE_CONNECTING, CLIENT_STATE_CONNECTED_IDLE);
+	}
+
+	FUNC_EXIT_RC(rc);
+}
+
+/**
+ * @brief Disconnect an MQTT Connection
+ *
+ * Called to send a disconnect message to the broker.
+ * This is the internal function which is called by the disconnect 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
+ *
+ * @return An IoT Error Type defining successful/failed send of the disconnect control packet.
+ */
+IoT_Error_t _aws_iot_mqtt_internal_disconnect(AWS_IoT_Client *pClient) {
+	/* We might wait for incomplete incoming publishes to complete */
+	TimerAWS timer;
+	size_t serialized_len = 0;
+	IoT_Error_t rc;
+
+	FUNC_ENTRY;
+
+	rc = aws_iot_mqtt_internal_serialize_zero(pClient->clientData.writeBuf, pClient->clientData.writeBufSize,
+											  DISCONNECT,
+											  &serialized_len);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+
+	init_timer(&timer);
+	countdown_ms(&timer, pClient->clientData.commandTimeoutMs);
+
+	/* send the disconnect packet */
+	if(serialized_len > 0) {
+		rc = aws_iot_mqtt_internal_send_packet(pClient, serialized_len, &timer);
+		if(SUCCESS != rc) {
+			FUNC_EXIT_RC(rc);
+		}
+	}
+
+	/* Clean network stack */
+	pClient->networkStack.disconnect(&(pClient->networkStack));
+	rc = pClient->networkStack.destroy(&(pClient->networkStack));
+	if(0 != rc) {
+		/* TLS Destroy failed, return error */
+		FUNC_EXIT_RC(FAILURE);
+	}
+
+	FUNC_EXIT_RC(SUCCESS);
+}
+
+/**
+ * @brief Disconnect an MQTT Connection
+ *
+ * Called to send a disconnect message to the broker.
+ * This is the outer function which does the validations and calls the internal disconnect above
+ * to perform the actual operation. It is also responsible for client state changes
+ *
+ * @param pClient Reference to the IoT Client
+ *
+ * @return An IoT Error Type defining successful/failed send of the disconnect control packet.
+ */
+IoT_Error_t aws_iot_mqtt_disconnect(AWS_IoT_Client *pClient) {
+	ClientState clientState;
+	IoT_Error_t rc;
+
+	FUNC_ENTRY;
+
+	if(NULL == pClient) {
+		FUNC_EXIT_RC(NULL_VALUE_ERROR);
+	}
+
+	clientState = aws_iot_mqtt_get_client_state(pClient);
+	if(!aws_iot_mqtt_is_client_connected(pClient)) {
+		/* Network is already disconnected. Do nothing */
+		FUNC_EXIT_RC(NETWORK_DISCONNECTED_ERROR);
+	}
+
+	rc = aws_iot_mqtt_set_client_state(pClient, clientState, CLIENT_STATE_DISCONNECTING);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+
+	rc = _aws_iot_mqtt_internal_disconnect(pClient);
+
+	if(SUCCESS != rc) {
+		pClient->clientStatus.clientState = clientState;
+	} else {
+		/* If called from Keepalive, this gets set to CLIENT_STATE_DISCONNECTED_ERROR */
+		pClient->clientStatus.clientState = CLIENT_STATE_DISCONNECTED_MANUALLY;
+	}
+
+	FUNC_EXIT_RC(rc);
+}
+
+/**
+ * @brief MQTT Manual Re-Connection Function
+ *
+ * Called to establish an MQTT connection with the AWS IoT Service
+ * using parameters from the last time a connection was attempted
+ * Use after disconnect to start the reconnect process manually
+ * Makes only one reconnect attempt. Sets the client state to
+ * pending reconnect in case of failure
+ *
+ * @param pClient Reference to the IoT Client
+ *
+ * @return An IoT Error Type defining successful/failed connection
+ */
+IoT_Error_t aws_iot_mqtt_attempt_reconnect(AWS_IoT_Client *pClient) {
+	IoT_Error_t rc;
+
+	FUNC_ENTRY;
+
+	if(NULL == pClient) {
+		FUNC_EXIT_RC(NULL_VALUE_ERROR);
+	}
+
+	if(aws_iot_mqtt_is_client_connected(pClient)) {
+		FUNC_EXIT_RC(NETWORK_ALREADY_CONNECTED_ERROR);
+	}
+
+	/* Ignoring return code. failures expected if network is disconnected */
+	rc = aws_iot_mqtt_connect(pClient, NULL);
+
+	/* If still disconnected handle disconnect */
+	if(CLIENT_STATE_CONNECTED_IDLE != aws_iot_mqtt_get_client_state(pClient)) {
+		aws_iot_mqtt_set_client_state(pClient, CLIENT_STATE_DISCONNECTED_ERROR, CLIENT_STATE_PENDING_RECONNECT);
+		FUNC_EXIT_RC(NETWORK_ATTEMPTING_RECONNECT);
+	}
+
+	rc = aws_iot_mqtt_resubscribe(pClient);
+	if(SUCCESS != rc) {
+		FUNC_EXIT_RC(rc);
+	}
+
+	FUNC_EXIT_RC(NETWORK_RECONNECTED);
+}
+
+#ifdef __cplusplus
+}
+#endif