File content as of revision 0:082731ede69f:

/*
* 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 <stdio.h>

#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((int)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(AWS_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;
    if (pConnectParams->isCleanSession)
    {
        flags.all |= 1 << 1;
    }

    if (pConnectParams->isWillMsgPresent)
    {
        flags.all |= 1 << 2;
        flags.all |= pConnectParams->will.qos << 3;
        flags.all |= pConnectParams->will.isRetained << 5;
    }

    if(pConnectParams->pPassword) {
        flags.all |= 1 << 6;
    }

    if(pConnectParams->pUsername) {
        flags.all |= 1 << 7;
    }

    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(pConnectParams->pUsername) {
        aws_iot_mqtt_internal_write_utf8_string(&ptr, pConnectParams->pUsername, pConnectParams->usernameLen);
    }

    if(pConnectParams->pPassword) {
        aws_iot_mqtt_internal_write_utf8_string(&ptr, pConnectParams->pPassword, pConnectParams->passwordLen);
    }

    *pSerializedLen = (size_t) (ptr - pTxBuf);

    FUNC_EXIT_RC(AWS_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 != MQTT_HEADER_FIELD_TYPE(header.byte)) {
        FUNC_EXIT_RC(FAILURE);
    }

    /* read remaining length */
    rc = aws_iot_mqtt_internal_decode_remaining_length_from_buffer(curdata, &decodedLen, &readBytesLen);
    if(AWS_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(AWS_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) {
    awsTimer 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(AWS_SUCCESS != rc) {
            FUNC_EXIT_RC(MQTT_CONNECTION_ERROR);
        }
    }

    rc = pClient->networkStack.connect(&(pClient->networkStack), NULL);
    if(AWS_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(AWS_SUCCESS != rc || 0 >= len) {
        FUNC_EXIT_RC(rc);
    }

    /* send the connect packet */
    rc = aws_iot_mqtt_internal_send_packet(pClient, len, &connect_timer);
    if(AWS_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(AWS_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(AWS_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(AWS_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(AWS_SUCCESS != rc) {
        pClient->networkStack.disconnect(&(pClient->networkStack));
        disconRc = pClient->networkStack.destroy(&(pClient->networkStack));
        if (AWS_SUCCESS != disconRc) {
            FUNC_EXIT_RC(NETWORK_DISCONNECTED_ERROR);
            }
        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 */
    awsTimer 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(AWS_SUCCESS != rc) {
        FUNC_EXIT_RC(rc);
    }

    init_timer(&timer);
    countdown_ms(&timer, pClient->clientData.commandTimeoutMs);

    /* send the disconnect packet */
    if(serialized_len > 0) {
        (void)aws_iot_mqtt_internal_send_packet(pClient, serialized_len, &timer);
    }

    /* 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(AWS_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(AWS_SUCCESS != rc) {
        FUNC_EXIT_RC(rc);
    }

    rc = _aws_iot_mqtt_internal_disconnect(pClient);

    if(AWS_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(AWS_SUCCESS != rc) {
        FUNC_EXIT_RC(rc);
    }

    FUNC_EXIT_RC(NETWORK_RECONNECTED);
}

#ifdef __cplusplus
}
#endif