[platform/upstream/iotivity.git] / resource / csdk / stack / src / ocstack.c

//******************************************************************
//
// Copyright 2014 Intel Mobile Communications GmbH 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.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License 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.
//
//-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=


//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------

// Defining _POSIX_C_SOURCE macro with 200112L (or greater) as value
// causes header files to expose definitions
// corresponding to the POSIX.1-2001 base
// specification (excluding the XSI extension).
// For POSIX.1-2001 base specification,
// Refer http://pubs.opengroup.org/onlinepubs/009695399/
#define _POSIX_C_SOURCE 200112L
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#ifndef __STDC_LIMIT_MACROS
#define __STDC_LIMIT_MACROS
#endif
#include <inttypes.h>
#include <string.h>
#include <ctype.h>

#include "ocstack.h"
#include "ocstackinternal.h"
#include "ocresourcehandler.h"
#include "occlientcb.h"
#include "ocobserve.h"
#include "ocrandom.h"
#include "oic_malloc.h"
#include "oic_string.h"
#include "logger.h"
#include "ocserverrequest.h"
#include "secureresourcemanager.h"
#include "psinterface.h"
#include "doxmresource.h"
#include "cacommon.h"
#include "cainterface.h"
#include "ocpayload.h"
#include "ocpayloadcbor.h"
#include "platform_features.h"

#if defined (ROUTING_GATEWAY) || defined (ROUTING_EP)
#include "routingutility.h"
#ifdef ROUTING_GATEWAY
#include "routingmanager.h"
#endif
#endif

#ifdef TCP_ADAPTER
#include "oickeepalive.h"
#endif

//#ifdef DIRECT_PAIRING
#include "directpairing.h"
//#endif

#ifdef HAVE_ARDUINO_TIME_H
#include "Time.h"
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include "coap_time.h"
#include "utlist.h"
#include "pdu.h"

#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif

#ifndef UINT32_MAX
#define UINT32_MAX   (0xFFFFFFFFUL)
#endif

//-----------------------------------------------------------------------------
// Typedefs
//-----------------------------------------------------------------------------
typedef enum
{
    OC_STACK_UNINITIALIZED = 0,
    OC_STACK_INITIALIZED,
    OC_STACK_UNINIT_IN_PROGRESS
} OCStackState;

#ifdef WITH_PRESENCE
typedef enum
{
    OC_PRESENCE_UNINITIALIZED = 0,
    OC_PRESENCE_INITIALIZED
} OCPresenceState;
#endif

//-----------------------------------------------------------------------------
// Private variables
//-----------------------------------------------------------------------------
static OCStackState stackState = OC_STACK_UNINITIALIZED;

OCResource *headResource = NULL;
static OCResource *tailResource = NULL;
static OCResourceHandle platformResource = {0};
static OCResourceHandle deviceResource = {0};
#ifdef MQ_BROKER
static OCResourceHandle brokerResource = {0};
#endif

#ifdef WITH_PRESENCE
static OCPresenceState presenceState = OC_PRESENCE_UNINITIALIZED;
static PresenceResource presenceResource = {0};
static uint8_t PresenceTimeOutSize = 0;
static uint32_t PresenceTimeOut[] = {50, 75, 85, 95, 100};
#endif

static OCMode myStackMode;
#ifdef RA_ADAPTER
//TODO: revisit this design
static bool gRASetInfo = false;
#endif
OCDeviceEntityHandler defaultDeviceHandler;
void* defaultDeviceHandlerCallbackParameter = NULL;
static const char COAP_TCP[] = "coap+tcp:";
static const char CORESPEC[] = "core";

//-----------------------------------------------------------------------------
// Macros
//-----------------------------------------------------------------------------
#define TAG  "OIC_RI_STACK"
#define VERIFY_SUCCESS(op, successCode) { if ((op) != (successCode)) \
            {OIC_LOG_V(FATAL, TAG, "%s failed!!", #op); goto exit;} }
#define VERIFY_NON_NULL(arg, logLevel, retVal) { if (!(arg)) { OIC_LOG((logLevel), \
             TAG, #arg " is NULL"); return (retVal); } }
#define VERIFY_NON_NULL_NR(arg, logLevel) { if (!(arg)) { OIC_LOG((logLevel), \
             TAG, #arg " is NULL"); return; } }
#define VERIFY_NON_NULL_V(arg) { if (!arg) {OIC_LOG(FATAL, TAG, #arg " is NULL");\
    goto exit;} }

//TODO: we should allow the server to define this
#define MAX_OBSERVE_AGE (0x2FFFFUL)

#define MILLISECONDS_PER_SECOND   (1000)

//-----------------------------------------------------------------------------
// Private internal function prototypes
//-----------------------------------------------------------------------------

/**
 * Generate handle of OCDoResource invocation for callback management.
 *
 * @return Generated OCDoResource handle.
 */
static OCDoHandle GenerateInvocationHandle();

/**
 * Initialize resource data structures, variables, etc.
 *
 * @return ::OC_STACK_OK on success, some other value upon failure.
 */
static OCStackResult initResources();

/**
 * Add a resource to the end of the linked list of resources.
 *
 * @param resource Resource to be added
 */
static void insertResource(OCResource *resource);

/**
 * Find a resource in the linked list of resources.
 *
 * @param resource Resource to be found.
 * @return Pointer to resource that was found in the linked list or NULL if the resource was not
 *         found.
 */
static OCResource *findResource(OCResource *resource);

/**
 * Insert a resource type into a resource's resource type linked list.
 * If resource type already exists, it will not be inserted and the
 * resourceType will be free'd.
 * resourceType->next should be null to avoid memory leaks.
 * Function returns silently for null args.
 *
 * @param resource Resource where resource type is to be inserted.
 * @param resourceType Resource type to be inserted.
 */
static void insertResourceType(OCResource *resource,
        OCResourceType *resourceType);

/**
 * Get a resource type at the specified index within a resource.
 *
 * @param handle Handle of resource.
 * @param index Index of resource type.
 *
 * @return Pointer to resource type if found, NULL otherwise.
 */
static OCResourceType *findResourceTypeAtIndex(OCResourceHandle handle,
        uint8_t index);

/**
 * Insert a resource interface into a resource's resource interface linked list.
 * If resource interface already exists, it will not be inserted and the
 * resourceInterface will be free'd.
 * resourceInterface->next should be null to avoid memory leaks.
 *
 * @param resource Resource where resource interface is to be inserted.
 * @param resourceInterface Resource interface to be inserted.
 */
static void insertResourceInterface(OCResource *resource,
        OCResourceInterface *resourceInterface);

/**
 * Get a resource interface at the specified index within a resource.
 *
 * @param handle Handle of resource.
 * @param index Index of resource interface.
 *
 * @return Pointer to resource interface if found, NULL otherwise.
 */
static OCResourceInterface *findResourceInterfaceAtIndex(
        OCResourceHandle handle, uint8_t index);

/**
 * Delete all of the dynamically allocated elements that were created for the resource type.
 *
 * @param resourceType Specified resource type.
 */
static void deleteResourceType(OCResourceType *resourceType);

/**
 * Delete all of the dynamically allocated elements that were created for the resource interface.
 *
 * @param resourceInterface Specified resource interface.
 */
static void deleteResourceInterface(OCResourceInterface *resourceInterface);

/**
 * Delete all of the dynamically allocated elements that were created for the resource.
 *
 * @param resource Specified resource.
 */
static void deleteResourceElements(OCResource *resource);

/**
 * Delete resource specified by handle.  Deletes resource and all resourcetype and resourceinterface
 * linked lists.
 *
 * @param handle Handle of resource to be deleted.
 *
 * @return ::OC_STACK_OK on success, some other value upon failure.
 */
static OCStackResult deleteResource(OCResource *resource);

/**
 * Delete all of the resources in the resource list.
 */
static void deleteAllResources();

/**
 * Increment resource sequence number.  Handles rollover.
 *
 * @param resPtr Pointer to resource.
 */
static void incrementSequenceNumber(OCResource * resPtr);

/*
 * Attempts to initialize every network interface that the CA Layer might have compiled in.
 *
 * Note: At least one interface must succeed to initialize. If all calls to @ref CASelectNetwork
 * return something other than @ref CA_STATUS_OK, then this function fails.
 *
 * @return ::CA_STATUS_OK on success, some other value upon failure.
 */
static CAResult_t OCSelectNetwork();

/**
 * Get the CoAP ticks after the specified number of milli-seconds.
 *
 * @param afterMilliSeconds Milli-seconds.
 * @return
 *     CoAP ticks
 */
static uint32_t GetTicks(uint32_t afterMilliSeconds);

/**
 * Convert CAResult_t to OCStackResult.
 *
 * @param caResult CAResult_t code.
 * @return ::OC_STACK_OK on success, some other value upon failure.
 */
static OCStackResult CAResultToOCStackResult(CAResult_t caResult);

/**
 * Convert CAResponseResult_t to OCStackResult.
 *
 * @param caCode CAResponseResult_t code.
 * @return ::OC_STACK_OK on success, some other value upon failure.
 */
static OCStackResult CAResponseToOCStackResult(CAResponseResult_t caCode);

/**
 * Convert OCStackResult to CAResponseResult_t.
 *
 * @param caCode OCStackResult code.
 * @param method OCMethod method the return code replies to.
 * @return ::CA_CONTENT on OK, some other value upon failure.
 */
static CAResponseResult_t OCToCAStackResult(OCStackResult ocCode, OCMethod method);

/**
 * Convert OCTransportFlags_t to CATransportModifiers_t.
 *
 * @param ocConType OCTransportFlags_t input.
 * @return CATransportFlags
 */
static CATransportFlags_t OCToCATransportFlags(OCTransportFlags ocConType);

/**
 * Convert CATransportFlags_t to OCTransportModifiers_t.
 *
 * @param caConType CATransportFlags_t input.
 * @return OCTransportFlags
 */
static OCTransportFlags CAToOCTransportFlags(CATransportFlags_t caConType);

/**
 * Handle response from presence request.
 *
 * @param endPoint CA remote endpoint.
 * @param responseInfo CA response info.
 * @return ::OC_STACK_OK on success, some other value upon failure.
 */
static OCStackResult HandlePresenceResponse(const CAEndpoint_t *endPoint,
        const CAResponseInfo_t *responseInfo);

/**
 * This function will be called back by CA layer when a response is received.
 *
 * @param endPoint CA remote endpoint.
 * @param responseInfo CA response info.
 */
static void HandleCAResponses(const CAEndpoint_t* endPoint,
        const CAResponseInfo_t* responseInfo);

/**
 * This function will be called back by CA layer when a request is received.
 *
 * @param endPoint CA remote endpoint.
 * @param requestInfo CA request info.
 */
static void HandleCARequests(const CAEndpoint_t* endPoint,
        const CARequestInfo_t* requestInfo);

/**
 * Extract query from a URI.
 *
 * @param uri Full URI with query.
 * @param query Pointer to string that will contain query.
 * @param newURI Pointer to string that will contain URI.
 * @return ::OC_STACK_OK on success, some other value upon failure.
 */
static OCStackResult getQueryFromUri(const char * uri, char** resourceType, char ** newURI);

/**
 * Finds a resource type in an OCResourceType link-list.
 *
 * @param resourceTypeList The link-list to be searched through.
 * @param resourceTypeName The key to search for.
 *
 * @return Resource type that matches the key (ie. resourceTypeName) or
 *      NULL if there is either an invalid parameter or this function was unable to find the key.
 */
static OCResourceType *findResourceType(OCResourceType * resourceTypeList,
        const char * resourceTypeName);

/**
 * Reset presence TTL for a ClientCB struct. ttlLevel will be set to 0.
 * TTL will be set to maxAge.
 *
 * @param cbNode Callback Node for which presence ttl is to be reset.
 * @param maxAge New value of ttl in seconds.

 * @return ::OC_STACK_OK on success, some other value upon failure.
 */
static OCStackResult ResetPresenceTTL(ClientCB *cbNode, uint32_t maxAgeSeconds);

/**
 * Ensure the accept header option is set appropriatly before sending the requests and routing
 * header option is updated with destination.
 *
 * @param object CA remote endpoint.
 * @param requestInfo CA request info.
 *
 * @return ::OC_STACK_OK on success, some other value upon failure.
 */
static OCStackResult OCSendRequest(const CAEndpoint_t *object, CARequestInfo_t *requestInfo);

//-----------------------------------------------------------------------------
// Internal functions
//-----------------------------------------------------------------------------

uint32_t GetTicks(uint32_t afterMilliSeconds)
{
    coap_tick_t now;
    coap_ticks(&now);

    // Guard against overflow of uint32_t
    if (afterMilliSeconds <= ((UINT32_MAX - (uint32_t)now) * MILLISECONDS_PER_SECOND) /
                             COAP_TICKS_PER_SECOND)
    {
        return now + (afterMilliSeconds * COAP_TICKS_PER_SECOND)/MILLISECONDS_PER_SECOND;
    }
    else
    {
        return UINT32_MAX;
    }
}

void CopyEndpointToDevAddr(const CAEndpoint_t *in, OCDevAddr *out)
{
    VERIFY_NON_NULL_NR(in, FATAL);
    VERIFY_NON_NULL_NR(out, FATAL);

    out->adapter = (OCTransportAdapter)in->adapter;
    out->flags = CAToOCTransportFlags(in->flags);
    OICStrcpy(out->addr, sizeof(out->addr), in->addr);
    out->port = in->port;
    out->ifindex = in->ifindex;
#if defined (ROUTING_GATEWAY) || defined (ROUTING_EP)
    /* This assert is to prevent accidental mismatch between address size macros defined in
     * RI and CA and cause crash here. */
    OC_STATIC_ASSERT(MAX_ADDR_STR_SIZE_CA == MAX_ADDR_STR_SIZE,
                                        "Address size mismatch between RI and CA");
    memcpy(out->routeData, in->routeData, sizeof(in->routeData));
#endif
}

void CopyDevAddrToEndpoint(const OCDevAddr *in, CAEndpoint_t *out)
{
    VERIFY_NON_NULL_NR(in, FATAL);
    VERIFY_NON_NULL_NR(out, FATAL);

    out->adapter = (CATransportAdapter_t)in->adapter;
    out->flags = OCToCATransportFlags(in->flags);
    OICStrcpy(out->addr, sizeof(out->addr), in->addr);
#if defined (ROUTING_GATEWAY) || defined (ROUTING_EP)
    /* This assert is to prevent accidental mismatch between address size macros defined in
     * RI and CA and cause crash here. */
    OC_STATIC_ASSERT(MAX_ADDR_STR_SIZE_CA == MAX_ADDR_STR_SIZE,
                                        "Address size mismatch between RI and CA");
    memcpy(out->routeData, in->routeData, sizeof(in->routeData));
#endif
    out->port = in->port;
    out->ifindex = in->ifindex;
}

void FixUpClientResponse(OCClientResponse *cr)
{
    VERIFY_NON_NULL_NR(cr, FATAL);

    cr->addr = &cr->devAddr;
    cr->connType = (OCConnectivityType)
        ((cr->devAddr.adapter << CT_ADAPTER_SHIFT) | (cr->devAddr.flags & CT_MASK_FLAGS));
}

static OCStackResult OCSendRequest(const CAEndpoint_t *object, CARequestInfo_t *requestInfo)
{
    VERIFY_NON_NULL(object, FATAL, OC_STACK_INVALID_PARAM);
    VERIFY_NON_NULL(requestInfo, FATAL, OC_STACK_INVALID_PARAM);

#if defined (ROUTING_GATEWAY) || defined (ROUTING_EP)
    OCStackResult rmResult = RMAddInfo(object->routeData, requestInfo, true, NULL);
    if (OC_STACK_OK != rmResult)
    {
        OIC_LOG(ERROR, TAG, "Add destination option failed");
        return rmResult;
    }
#endif

    // OC stack prefer CBOR encoded payloads.
    requestInfo->info.acceptFormat = CA_FORMAT_APPLICATION_CBOR;
    CAResult_t result = CASendRequest(object, requestInfo);
    if(CA_STATUS_OK != result)
    {
        OIC_LOG_V(ERROR, TAG, "CASendRequest failed with CA error %u", result);
        return CAResultToOCResult(result);
    }
    return OC_STACK_OK;
}
//-----------------------------------------------------------------------------
// Internal API function
//-----------------------------------------------------------------------------

// This internal function is called to update the stack with the status of
// observers and communication failures
OCStackResult OCStackFeedBack(CAToken_t token, uint8_t tokenLength, uint8_t status)
{
    OCStackResult result = OC_STACK_ERROR;
    ResourceObserver * observer = NULL;
    OCEntityHandlerRequest ehRequest = {0};

    switch(status)
    {
    case OC_OBSERVER_NOT_INTERESTED:
        OIC_LOG(DEBUG, TAG, "observer not interested in our notifications");
        observer = GetObserverUsingToken (token, tokenLength);
        if(observer)
        {
            result = FormOCEntityHandlerRequest(&ehRequest,
                                                (OCRequestHandle)NULL,
                                                OC_REST_NOMETHOD,
                                                &observer->devAddr,
                                                (OCResourceHandle)NULL,
                                                NULL, PAYLOAD_TYPE_REPRESENTATION,
                                                NULL, 0, 0, NULL,
                                                OC_OBSERVE_DEREGISTER,
                                                observer->observeId,
                                                0);
            if(result != OC_STACK_OK)
            {
                return result;
            }
            observer->resource->entityHandler(OC_OBSERVE_FLAG, &ehRequest,
                            observer->resource->entityHandlerCallbackParam);
        }

        result = DeleteObserverUsingToken (token, tokenLength);
        if(result == OC_STACK_OK)
        {
            OIC_LOG(DEBUG, TAG, "Removed observer successfully");
        }
        else
        {
            result = OC_STACK_OK;
            OIC_LOG(DEBUG, TAG, "Observer Removal failed");
        }
        break;

    case OC_OBSERVER_STILL_INTERESTED:
        OIC_LOG(DEBUG, TAG, "observer still interested, reset the failedCount");
        observer = GetObserverUsingToken (token, tokenLength);
        if(observer)
        {
            observer->forceHighQos = 0;
            observer->failedCommCount = 0;
            result = OC_STACK_OK;
        }
        else
        {
            result = OC_STACK_OBSERVER_NOT_FOUND;
        }
        break;

    case OC_OBSERVER_FAILED_COMM:
        OIC_LOG(DEBUG, TAG, "observer is unreachable");
        observer = GetObserverUsingToken (token, tokenLength);
        if(observer)
        {
            if(observer->failedCommCount >= MAX_OBSERVER_FAILED_COMM)
            {
                result = FormOCEntityHandlerRequest(&ehRequest,
                                                    (OCRequestHandle)NULL,
                                                    OC_REST_NOMETHOD,
                                                    &observer->devAddr,
                                                    (OCResourceHandle)NULL,
                                                    NULL, PAYLOAD_TYPE_REPRESENTATION,
                                                    NULL, 0, 0, NULL,
                                                    OC_OBSERVE_DEREGISTER,
                                                    observer->observeId,
                                                    0);
                if(result != OC_STACK_OK)
                {
                    return OC_STACK_ERROR;
                }
                observer->resource->entityHandler(OC_OBSERVE_FLAG, &ehRequest,
                                    observer->resource->entityHandlerCallbackParam);

                result = DeleteObserverUsingToken (token, tokenLength);
                if(result == OC_STACK_OK)
                {
                    OIC_LOG(DEBUG, TAG, "Removed observer successfully");
                }
                else
                {
                    result = OC_STACK_OK;
                    OIC_LOG(DEBUG, TAG, "Observer Removal failed");
                }
            }
            else
            {
                observer->failedCommCount++;
                result = OC_STACK_CONTINUE;
            }
            observer->forceHighQos = 1;
            OIC_LOG_V(DEBUG, TAG, "Failed count for this observer is %d",observer->failedCommCount);
        }
        break;
    default:
        OIC_LOG(ERROR, TAG, "Unknown status");
        result = OC_STACK_ERROR;
        break;
        }
    return result;
}

static OCStackResult CAResultToOCStackResult(CAResult_t caResult)
{
    OCStackResult ret = OC_STACK_ERROR;

    switch(caResult)
    {
        case CA_ADAPTER_NOT_ENABLED:
        case CA_SERVER_NOT_STARTED:
            ret = OC_STACK_ADAPTER_NOT_ENABLED;
            break;
        case CA_MEMORY_ALLOC_FAILED:
            ret = OC_STACK_NO_MEMORY;
            break;
        case CA_STATUS_INVALID_PARAM:
            ret = OC_STACK_INVALID_PARAM;
            break;
        default:
            break;
    }
    return ret;
}

OCStackResult CAResponseToOCStackResult(CAResponseResult_t caCode)
{
    OCStackResult ret = OC_STACK_ERROR;
    switch(caCode)
    {
        case CA_CREATED:
            ret = OC_STACK_RESOURCE_CREATED;
            break;
        case CA_DELETED:
            ret = OC_STACK_RESOURCE_DELETED;
            break;
        case CA_CHANGED:
            ret = OC_STACK_RESOURCE_CHANGED;
            break;
        case CA_CONTENT:
        case CA_VALID:
            ret = OC_STACK_OK;
            break;
        case CA_BAD_REQ:
            ret = OC_STACK_INVALID_QUERY;
            break;
        case CA_UNAUTHORIZED_REQ:
            ret = OC_STACK_UNAUTHORIZED_REQ;
            break;
        case CA_BAD_OPT:
            ret = OC_STACK_INVALID_OPTION;
            break;
        case CA_NOT_FOUND:
            ret = OC_STACK_NO_RESOURCE;
            break;
        case CA_RETRANSMIT_TIMEOUT:
            ret = OC_STACK_COMM_ERROR;
            break;
        case CA_REQUEST_ENTITY_TOO_LARGE:
            ret = OC_STACK_TOO_LARGE_REQ;
            break;
        default:
            break;
    }
    return ret;
}

CAResponseResult_t OCToCAStackResult(OCStackResult ocCode, OCMethod method)
{
    CAResponseResult_t ret = CA_INTERNAL_SERVER_ERROR;

    switch(ocCode)
    {
        case OC_STACK_OK:
           switch (method)
           {
               case OC_REST_PUT:
               case OC_REST_POST:
                   // This Response Code is like HTTP 204 "No Content" but only used in
                   // response to POST and PUT requests.
                   ret = CA_CHANGED;
                   break;
               case OC_REST_GET:
                   // This Response Code is like HTTP 200 "OK" but only used in response to
                   // GET requests.
                   ret = CA_CONTENT;
                   break;
               default:
                   // This should not happen but,
                   // give it a value just in case but output an error
                   ret = CA_CONTENT;
                   OIC_LOG_V(ERROR, TAG, "Unexpected OC_STACK_OK return code for method [%d].",
                            method);
            }
            break;
        case OC_STACK_RESOURCE_CREATED:
            ret = CA_CREATED;
            break;
        case OC_STACK_RESOURCE_DELETED:
            ret = CA_DELETED;
            break;
        case OC_STACK_RESOURCE_CHANGED:
            ret = CA_CHANGED;
            break;
        case OC_STACK_INVALID_QUERY:
            ret = CA_BAD_REQ;
            break;
        case OC_STACK_INVALID_OPTION:
            ret = CA_BAD_OPT;
            break;
        case OC_STACK_NO_RESOURCE:
            ret = CA_NOT_FOUND;
            break;
        case OC_STACK_COMM_ERROR:
            ret = CA_RETRANSMIT_TIMEOUT;
            break;
        case OC_STACK_UNAUTHORIZED_REQ:
            ret = CA_UNAUTHORIZED_REQ;
            break;
        default:
            break;
    }
    return ret;
}

CATransportFlags_t OCToCATransportFlags(OCTransportFlags ocFlags)
{
    CATransportFlags_t caFlags = (CATransportFlags_t)ocFlags;

    // supply default behavior.
    if ((caFlags & (CA_IPV6|CA_IPV4)) == 0)
    {
        caFlags = (CATransportFlags_t)(caFlags|CA_IPV6|CA_IPV4);
    }
    if ((caFlags & OC_MASK_SCOPE) == 0)
    {
        caFlags = (CATransportFlags_t)(caFlags|OC_SCOPE_LINK);
    }
    return caFlags;
}

OCTransportFlags CAToOCTransportFlags(CATransportFlags_t caFlags)
{
    return (OCTransportFlags)caFlags;
}

static OCStackResult ResetPresenceTTL(ClientCB *cbNode, uint32_t maxAgeSeconds)
{
    uint32_t lowerBound  = 0;
    uint32_t higherBound = 0;

    if (!cbNode || !cbNode->presence || !cbNode->presence->timeOut)
    {
        return OC_STACK_INVALID_PARAM;
    }

    OIC_LOG_V(INFO, TAG, "Update presence TTL, time is %u", GetTicks(0));

    cbNode->presence->TTL = maxAgeSeconds;

    for (int index = 0; index < PresenceTimeOutSize; index++)
    {
        // Guard against overflow
        if (cbNode->presence->TTL < (UINT32_MAX/(MILLISECONDS_PER_SECOND*PresenceTimeOut[index]))
                                     * 100)
        {
            lowerBound = GetTicks((PresenceTimeOut[index] *
                                  cbNode->presence->TTL *
                                  MILLISECONDS_PER_SECOND)/100);
        }
        else
        {
            lowerBound = GetTicks(UINT32_MAX);
        }

        if (cbNode->presence->TTL < (UINT32_MAX/(MILLISECONDS_PER_SECOND*PresenceTimeOut[index+1]))
                                     * 100)
        {
            higherBound = GetTicks((PresenceTimeOut[index + 1] *
                                   cbNode->presence->TTL *
                                   MILLISECONDS_PER_SECOND)/100);
        }
        else
        {
            higherBound = GetTicks(UINT32_MAX);
        }

        cbNode->presence->timeOut[index] = OCGetRandomRange(lowerBound, higherBound);

        OIC_LOG_V(DEBUG, TAG, "lowerBound timeout  %d", lowerBound);
        OIC_LOG_V(DEBUG, TAG, "higherBound timeout %d", higherBound);
        OIC_LOG_V(DEBUG, TAG, "timeOut entry  %d", cbNode->presence->timeOut[index]);
    }

    cbNode->presence->TTLlevel = 0;

    OIC_LOG_V(DEBUG, TAG, "this TTL level %d", cbNode->presence->TTLlevel);
    return OC_STACK_OK;
}

const char *convertTriggerEnumToString(OCPresenceTrigger trigger)
{
    if (trigger == OC_PRESENCE_TRIGGER_CREATE)
    {
        return OC_RSRVD_TRIGGER_CREATE;
    }
    else if (trigger == OC_PRESENCE_TRIGGER_CHANGE)
    {
        return OC_RSRVD_TRIGGER_CHANGE;
    }
    else
    {
        return OC_RSRVD_TRIGGER_DELETE;
    }
}

OCPresenceTrigger convertTriggerStringToEnum(const char * triggerStr)
{
    if(!triggerStr)
    {
        return OC_PRESENCE_TRIGGER_CREATE;
    }
    else if(strcmp(triggerStr, OC_RSRVD_TRIGGER_CREATE) == 0)
    {
        return OC_PRESENCE_TRIGGER_CREATE;
    }
    else if(strcmp(triggerStr, OC_RSRVD_TRIGGER_CHANGE) == 0)
    {
        return OC_PRESENCE_TRIGGER_CHANGE;
    }
    else
    {
        return OC_PRESENCE_TRIGGER_DELETE;
    }
}

/**
 * Encode an address string to match RFC6874.
 *
 * @param outputAddress    a char array to be written with the encoded string.
 *
 * @param outputSize       size of outputAddress buffer.
 *
 * @param inputAddress     a char array of size <= CA_MAX_URI_LENGTH
 *                         containing a valid IPv6 address string.
 *
 * @return                 OC_STACK_OK if encoding succeeded.
 *                         Else an error occured.
 */
 OCStackResult encodeAddressForRFC6874(char *outputAddress,
                                       size_t outputSize,
                                       const char *inputAddress)
{
    VERIFY_NON_NULL(inputAddress,  FATAL, OC_STACK_INVALID_PARAM);
    VERIFY_NON_NULL(outputAddress, FATAL, OC_STACK_INVALID_PARAM);

    /** @todo Use a max IPv6 string length instead of CA_MAX_URI_LENGTH. */
#define ENCODE_MAX_INPUT_LENGTH    CA_MAX_URI_LENGTH

    size_t inputLength = strnlen(inputAddress, ENCODE_MAX_INPUT_LENGTH);

    if (inputLength >= ENCODE_MAX_INPUT_LENGTH)
    {
        OIC_LOG(ERROR, TAG,
                "encodeAddressForRFC6874 failed: Invalid input string: too long/unterminated!");
        return OC_STACK_INVALID_PARAM;
    }

    // inputSize includes the null terminator
    size_t inputSize = inputLength + 1;

    if (inputSize > outputSize)
    {
        OIC_LOG_V(ERROR, TAG,
                  "encodeAddressForRFC6874 failed: "
                  "outputSize (%d) < inputSize (%d)",
                  outputSize, inputSize);

        return OC_STACK_ERROR;
    }

    char* percentChar = strchr(inputAddress, '%');

    // If there is no '%' character, then no change is required to the string.
    if (NULL == percentChar)
    {
        OICStrcpy(outputAddress, outputSize, inputAddress);
        return OC_STACK_OK;
    }

    const char* addressPart = &inputAddress[0];
    const char* scopeIdPart = percentChar + 1;

    // Sanity check to make sure this string doesn't have more '%' characters
    if (NULL != strchr(scopeIdPart, '%'))
    {
        return OC_STACK_ERROR;
    }

    // If no string follows the first '%', then the input was invalid.
    if (scopeIdPart[0] == '\0')
    {
        OIC_LOG(ERROR, TAG, "encodeAddressForRFC6874 failed: Invalid input string: no scope ID!");
        return OC_STACK_ERROR;
    }

    // Check to see if the string is already encoded
    if ((scopeIdPart[0] == '2') && (scopeIdPart[1] == '5'))
    {
        OIC_LOG(ERROR, TAG, "encodeAddressForRFC6874 failed: Input string is already encoded");
        return OC_STACK_ERROR;
    }

    // Fail if we don't have room for encoded string's two additional chars
    if (outputSize < (inputSize + 2))
    {
        OIC_LOG(ERROR, TAG, "encodeAddressForRFC6874 failed: Input string is already encoded");
        return OC_STACK_ERROR;
    }

    // Restore the null terminator with an escaped '%' character, per RFC6874
    OICStrcpy(outputAddress, scopeIdPart - addressPart, addressPart);
    strcat(outputAddress, "%25");
    strcat(outputAddress, scopeIdPart);

    return OC_STACK_OK;
}

/**
 * The cononical presence allows constructed URIs to be string compared.
 *
 * requestUri must be a char array of size CA_MAX_URI_LENGTH
 */
static int FormCanonicalPresenceUri(const CAEndpoint_t *endpoint, char *resourceUri,
        char *presenceUri)
{
    VERIFY_NON_NULL(endpoint   , FATAL, OC_STACK_INVALID_PARAM);
    VERIFY_NON_NULL(resourceUri, FATAL, OC_STACK_INVALID_PARAM);
    VERIFY_NON_NULL(presenceUri, FATAL, OC_STACK_INVALID_PARAM);

    CAEndpoint_t *ep = (CAEndpoint_t *)endpoint;

    if (ep->adapter == CA_ADAPTER_IP)
    {
        if ((ep->flags & CA_IPV6) && !(ep->flags & CA_IPV4))
        {
            if ('\0' == ep->addr[0])  // multicast
            {
                return snprintf(presenceUri, CA_MAX_URI_LENGTH, OC_RSRVD_PRESENCE_URI);
            }
            else
            {
                char addressEncoded[CA_MAX_URI_LENGTH] = {0};

                OCStackResult result = encodeAddressForRFC6874(addressEncoded,
                                                               sizeof(addressEncoded),
                                                               ep->addr);

                if (OC_STACK_OK != result)
                {
                    return -1;
                }

                return snprintf(presenceUri, CA_MAX_URI_LENGTH, "coap://[%s]:%u%s",
                        addressEncoded, ep->port, OC_RSRVD_PRESENCE_URI);
            }
        }
        else
        {
            if ('\0' == ep->addr[0])  // multicast
            {
                OICStrcpy(ep->addr, sizeof(ep->addr), OC_MULTICAST_IP);
                ep->port = OC_MULTICAST_PORT;
            }
            return snprintf(presenceUri, CA_MAX_URI_LENGTH, "coap://%s:%u%s",
                    ep->addr, ep->port, OC_RSRVD_PRESENCE_URI);
        }
    }

    // might work for other adapters (untested, but better than nothing)
    return snprintf(presenceUri, CA_MAX_URI_LENGTH, "coap://%s%s", ep->addr,
                    OC_RSRVD_PRESENCE_URI);
}


OCStackResult HandlePresenceResponse(const CAEndpoint_t *endpoint,
                            const CAResponseInfo_t *responseInfo)
{
    VERIFY_NON_NULL(endpoint, FATAL, OC_STACK_INVALID_PARAM);
    VERIFY_NON_NULL(responseInfo, FATAL, OC_STACK_INVALID_PARAM);

    OCStackApplicationResult cbResult = OC_STACK_DELETE_TRANSACTION;
    ClientCB * cbNode = NULL;
    char *resourceTypeName = NULL;
    OCClientResponse response = {.devAddr = {.adapter = OC_DEFAULT_ADAPTER}};
    OCStackResult result = OC_STACK_ERROR;
    uint32_t maxAge = 0;
    int uriLen;
    char presenceUri[CA_MAX_URI_LENGTH];

    int presenceSubscribe = 0;
    int multicastPresenceSubscribe = 0;

    if (responseInfo->result != CA_CONTENT)
    {
        OIC_LOG_V(ERROR, TAG, "HandlePresenceResponse failed %d", responseInfo->result);
        return OC_STACK_ERROR;
    }

    // check for unicast presence
    uriLen = FormCanonicalPresenceUri(endpoint, OC_RSRVD_PRESENCE_URI, presenceUri);
    if (uriLen < 0 || (size_t)uriLen >= sizeof (presenceUri))
    {
        return OC_STACK_INVALID_URI;
    }

    cbNode = GetClientCB(NULL, 0, NULL, presenceUri);
    if (cbNode)
    {
        presenceSubscribe = 1;
    }
    else
    {
        // check for multiicast presence
        CAEndpoint_t ep = { .adapter = endpoint->adapter,
                            .flags = endpoint->flags };

        uriLen = FormCanonicalPresenceUri(&ep, OC_RSRVD_PRESENCE_URI, presenceUri);

        cbNode = GetClientCB(NULL, 0, NULL, presenceUri);
        if (cbNode)
        {
            multicastPresenceSubscribe = 1;
        }
    }

    if (!presenceSubscribe && !multicastPresenceSubscribe)
    {
        OIC_LOG(ERROR, TAG, "Received a presence notification, but no callback, ignoring");
        goto exit;
    }

    response.payload = NULL;
    response.result = OC_STACK_OK;

    CopyEndpointToDevAddr(endpoint, &response.devAddr);
    FixUpClientResponse(&response);

    if (responseInfo->info.payload)
    {
        result = OCParsePayload(&response.payload,
                PAYLOAD_TYPE_PRESENCE,
                responseInfo->info.payload,
                responseInfo->info.payloadSize);

        if(result != OC_STACK_OK)
        {
            OIC_LOG(ERROR, TAG, "Presence parse failed");
            goto exit;
        }
        if(!response.payload || response.payload->type != PAYLOAD_TYPE_PRESENCE)
        {
            OIC_LOG(ERROR, TAG, "Presence payload was wrong type");
            result = OC_STACK_ERROR;
            goto exit;
        }
        response.sequenceNumber = ((OCPresencePayload*)response.payload)->sequenceNumber;
        resourceTypeName = ((OCPresencePayload*)response.payload)->resourceType;
        maxAge = ((OCPresencePayload*)response.payload)->maxAge;
    }

    if (presenceSubscribe)
    {
        if(cbNode->sequenceNumber == response.sequenceNumber)
        {
            OIC_LOG(INFO, TAG, "No presence change");
            ResetPresenceTTL(cbNode, maxAge);
            OIC_LOG_V(INFO, TAG, "ResetPresenceTTL - TTLlevel:%d\n", cbNode->presence->TTLlevel);
            goto exit;
        }

        if(maxAge == 0)
        {
            OIC_LOG(INFO, TAG, "Stopping presence");
            response.result = OC_STACK_PRESENCE_STOPPED;
            if(cbNode->presence)
            {
                OICFree(cbNode->presence->timeOut);
                OICFree(cbNode->presence);
                cbNode->presence = NULL;
            }
        }
        else
        {
            if(!cbNode->presence)
            {
                cbNode->presence = (OCPresence *)OICMalloc(sizeof (OCPresence));

                if(!(cbNode->presence))
                {
                    OIC_LOG(ERROR, TAG, "Could not allocate memory for cbNode->presence");
                    result = OC_STACK_NO_MEMORY;
                    goto exit;
                }

                VERIFY_NON_NULL_V(cbNode->presence);
                cbNode->presence->timeOut = NULL;
                cbNode->presence->timeOut = (uint32_t *)
                        OICMalloc(PresenceTimeOutSize * sizeof(uint32_t));
                if(!(cbNode->presence->timeOut)){
                    OIC_LOG(ERROR, TAG,
                                  "Could not allocate memory for cbNode->presence->timeOut");
                    OICFree(cbNode->presence);
                    result = OC_STACK_NO_MEMORY;
                    goto exit;
                }
            }

            ResetPresenceTTL(cbNode, maxAge);

            cbNode->sequenceNumber = response.sequenceNumber;

            // Ensure that a filter is actually applied.
            if( resourceTypeName && cbNode->filterResourceType)
            {
                if(!findResourceType(cbNode->filterResourceType, resourceTypeName))
                {
                    goto exit;
                }
            }
        }
    }
    else
    {
        // This is the multicast case
        OCMulticastNode* mcNode = NULL;
        mcNode = GetMCPresenceNode(presenceUri);

        if(mcNode != NULL)
        {
            if(mcNode->nonce == response.sequenceNumber)
            {
                OIC_LOG(INFO, TAG, "No presence change (Multicast)");
                goto exit;
            }
            mcNode->nonce = response.sequenceNumber;

            if(maxAge == 0)
            {
                OIC_LOG(INFO, TAG, "Stopping presence");
                response.result = OC_STACK_PRESENCE_STOPPED;
            }
        }
        else
        {
            char* uri = OICStrdup(presenceUri);
            if (!uri)
            {
                OIC_LOG(INFO, TAG,
                    "No Memory for URI to store in the presence node");
                result = OC_STACK_NO_MEMORY;
                goto exit;
            }

            result = AddMCPresenceNode(&mcNode, uri, response.sequenceNumber);
            if(result == OC_STACK_NO_MEMORY)
            {
                OIC_LOG(INFO, TAG,
                    "No Memory for Multicast Presence Node");
                OICFree(uri);
                goto exit;
            }
            // presence node now owns uri
        }

        // Ensure that a filter is actually applied.
        if(resourceTypeName && cbNode->filterResourceType)
        {
            if(!findResourceType(cbNode->filterResourceType, resourceTypeName))
            {
                goto exit;
            }
        }
    }

    cbResult = cbNode->callBack(cbNode->context, cbNode->handle, &response);

    if (cbResult == OC_STACK_DELETE_TRANSACTION)
    {
        FindAndDeleteClientCB(cbNode);
    }

exit:
    OCPayloadDestroy(response.payload);
    return result;
}

void OCHandleResponse(const CAEndpoint_t* endPoint, const CAResponseInfo_t* responseInfo)
{
    OIC_LOG(DEBUG, TAG, "Enter OCHandleResponse");

    if(responseInfo->info.resourceUri &&
        strcmp(responseInfo->info.resourceUri, OC_RSRVD_PRESENCE_URI) == 0)
    {
        HandlePresenceResponse(endPoint, responseInfo);
        return;
    }

    ClientCB *cbNode = GetClientCB(responseInfo->info.token,
            responseInfo->info.tokenLength, NULL, NULL);

    ResourceObserver * observer = GetObserverUsingToken (responseInfo->info.token,
            responseInfo->info.tokenLength);

    if(cbNode)
    {
        OIC_LOG(INFO, TAG, "There is a cbNode associated with the response token");
        if(responseInfo->result == CA_EMPTY)
        {
            OIC_LOG(INFO, TAG, "Receiving A ACK/RESET for this token");
            // We do not have a case for the client to receive a RESET
            if(responseInfo->info.type == CA_MSG_ACKNOWLEDGE)
            {
                //This is the case of receiving an ACK on a request to a slow resource!
                OIC_LOG(INFO, TAG, "This is a pure ACK");
                //TODO: should we inform the client
                //      app that at least the request was received at the server?
            }
        }
        else if(responseInfo->result == CA_RETRANSMIT_TIMEOUT)
        {
            OIC_LOG(INFO, TAG, "Receiving A Timeout for this token");
            OIC_LOG(INFO, TAG, "Calling into application address space");

            OCClientResponse response =
                {.devAddr = {.adapter = OC_DEFAULT_ADAPTER}};
            CopyEndpointToDevAddr(endPoint, &response.devAddr);
            FixUpClientResponse(&response);
            response.resourceUri = responseInfo->info.resourceUri;
            memcpy(response.identity.id, responseInfo->info.identity.id,
                                                sizeof (response.identity.id));
            response.identity.id_length = responseInfo->info.identity.id_length;

            response.result = CAResponseToOCStackResult(responseInfo->result);
            cbNode->callBack(cbNode->context,
                    cbNode->handle, &response);
            FindAndDeleteClientCB(cbNode);
        }
        else
        {
            OIC_LOG(INFO, TAG, "This is a regular response, A client call back is found");
            OIC_LOG(INFO, TAG, "Calling into application address space");

            OCClientResponse response =
                {.devAddr = {.adapter = OC_DEFAULT_ADAPTER}};
            response.sequenceNumber = MAX_SEQUENCE_NUMBER + 1;
            CopyEndpointToDevAddr(endPoint, &response.devAddr);
            FixUpClientResponse(&response);
            response.resourceUri = responseInfo->info.resourceUri;
            memcpy(response.identity.id, responseInfo->info.identity.id,
                                                sizeof (response.identity.id));
            response.identity.id_length = responseInfo->info.identity.id_length;

            response.result = CAResponseToOCStackResult(responseInfo->result);

            if(responseInfo->info.payload &&
               responseInfo->info.payloadSize)
            {
                OCPayloadType type = PAYLOAD_TYPE_INVALID;
                // check the security resource
                if (SRMIsSecurityResourceURI(cbNode->requestUri))
                {
                    type = PAYLOAD_TYPE_SECURITY;
                }
                else if (cbNode->method == OC_REST_DISCOVER)
                {
                    if (strncmp(OC_RSRVD_WELL_KNOWN_URI,cbNode->requestUri,
                                sizeof(OC_RSRVD_WELL_KNOWN_URI) - 1) == 0)
                    {
                        type = PAYLOAD_TYPE_DISCOVERY;
                    }
#ifdef WITH_MQ
                    else if (strcmp(cbNode->requestUri, OC_RSRVD_WELL_KNOWN_MQ_URI) == 0)
                    {
                        type = PAYLOAD_TYPE_DISCOVERY;
                    }
#endif
                    else if (strcmp(cbNode->requestUri, OC_RSRVD_DEVICE_URI) == 0)
                    {
                        type = PAYLOAD_TYPE_DEVICE;
                    }
                    else if (strcmp(cbNode->requestUri, OC_RSRVD_PLATFORM_URI) == 0)
                    {
                        type = PAYLOAD_TYPE_PLATFORM;
                    }
#ifdef ROUTING_GATEWAY
                    else if (strcmp(cbNode->requestUri, OC_RSRVD_GATEWAY_URI) == 0)
                    {
                        type = PAYLOAD_TYPE_REPRESENTATION;
                    }
#endif
                    else if (strcmp(cbNode->requestUri, OC_RSRVD_RD_URI) == 0)
                    {
                        type = PAYLOAD_TYPE_RD;
                    }
#ifdef TCP_ADAPTER
                    else if (strcmp(cbNode->requestUri, KEEPALIVE_RESOURCE_URI) == 0)
                    {
                        type = PAYLOAD_TYPE_REPRESENTATION;
                    }
#endif
                    else
                    {
                        OIC_LOG_V(ERROR, TAG, "Unknown Payload type in Discovery: %d %s",
                                cbNode->method, cbNode->requestUri);
                        return;
                    }
                }
                else if (cbNode->method == OC_REST_GET ||
                         cbNode->method == OC_REST_PUT ||
                         cbNode->method == OC_REST_POST ||
                         cbNode->method == OC_REST_OBSERVE ||
                         cbNode->method == OC_REST_OBSERVE_ALL ||
                         cbNode->method == OC_REST_DELETE)
                {
                    char targetUri[MAX_URI_LENGTH];
                    snprintf(targetUri, MAX_URI_LENGTH, "%s?rt=%s", OC_RSRVD_RD_URI,
                            OC_RSRVD_RESOURCE_TYPE_RDPUBLISH);
                    if (strcmp(targetUri, cbNode->requestUri) == 0)
                    {
                        type = PAYLOAD_TYPE_RD;
                    }
                    else if (strcmp(OC_RSRVD_PLATFORM_URI, cbNode->requestUri) == 0)
                    {
                        type = PAYLOAD_TYPE_PLATFORM;
                    }
                    else if (strcmp(OC_RSRVD_DEVICE_URI, cbNode->requestUri) == 0)
                    {
                        type = PAYLOAD_TYPE_DEVICE;
                    }
                    if (type == PAYLOAD_TYPE_INVALID)
                    {
                        OIC_LOG_V(INFO, TAG, "Assuming PAYLOAD_TYPE_REPRESENTATION: %d %s",
                                cbNode->method, cbNode->requestUri);
                        type = PAYLOAD_TYPE_REPRESENTATION;
                    }
                }
                else
                {
                    OIC_LOG_V(ERROR, TAG, "Unknown Payload type: %d %s",
                            cbNode->method, cbNode->requestUri);
                    return;
                }

                if(OC_STACK_OK != OCParsePayload(&response.payload,
                            type,
                            responseInfo->info.payload,
                            responseInfo->info.payloadSize))
                {
                    OIC_LOG(ERROR, TAG, "Error converting payload");
                    OCPayloadDestroy(response.payload);
                    return;
                }
            }

            response.numRcvdVendorSpecificHeaderOptions = 0;
            if(responseInfo->info.numOptions > 0)
            {
                int start = 0;
                //First option always with option ID is COAP_OPTION_OBSERVE if it is available.
                if(responseInfo->info.options[0].optionID == COAP_OPTION_OBSERVE)
                {
                    size_t i;
                    uint32_t observationOption;
                    uint8_t* optionData = (uint8_t*)responseInfo->info.options[0].optionData;
                    for (observationOption=0, i=0;
                            i<sizeof(uint32_t) && i<responseInfo->info.options[0].optionLength;
                            i++)
                    {
                        observationOption =
                            (observationOption << 8) | optionData[i];
                    }
                    response.sequenceNumber = observationOption;
                    response.numRcvdVendorSpecificHeaderOptions = responseInfo->info.numOptions - 1;
                    start = 1;
                }
                else
                {
                    response.numRcvdVendorSpecificHeaderOptions = responseInfo->info.numOptions;
                }

                if(response.numRcvdVendorSpecificHeaderOptions > MAX_HEADER_OPTIONS)
                {
                    OIC_LOG(ERROR, TAG, "#header options are more than MAX_HEADER_OPTIONS");
                    OCPayloadDestroy(response.payload);
                    return;
                }

                for (uint8_t i = start; i < responseInfo->info.numOptions; i++)
                {
                    memcpy (&(response.rcvdVendorSpecificHeaderOptions[i-start]),
                            &(responseInfo->info.options[i]), sizeof(OCHeaderOption));
                }
            }

            if (cbNode->method == OC_REST_OBSERVE &&
                response.sequenceNumber > OC_OFFSET_SEQUENCE_NUMBER &&
                cbNode->sequenceNumber <=  MAX_SEQUENCE_NUMBER &&
                response.sequenceNumber <= cbNode->sequenceNumber)
            {
                OIC_LOG_V(INFO, TAG, "Received stale notification. Number :%d",
                                                 response.sequenceNumber);
            }
            else
            {
                OCStackApplicationResult appFeedback = cbNode->callBack(cbNode->context,
                                                                        cbNode->handle,
                                                                        &response);
                cbNode->sequenceNumber = response.sequenceNumber;

                if (appFeedback == OC_STACK_DELETE_TRANSACTION)
                {
                    FindAndDeleteClientCB(cbNode);
                }
                else
                {
                    // To keep discovery callbacks active.
                    cbNode->TTL = GetTicks(MAX_CB_TIMEOUT_SECONDS *
                                            MILLISECONDS_PER_SECOND);
                }
            }

            //Need to send ACK when the response is CON
            if(responseInfo->info.type == CA_MSG_CONFIRM)
            {
                SendDirectStackResponse(endPoint, responseInfo->info.messageId, CA_EMPTY,
                        CA_MSG_ACKNOWLEDGE, 0, NULL, NULL, 0, NULL, CA_RESPONSE_FOR_RES);
            }

            OCPayloadDestroy(response.payload);
        }
        return;
    }

    if(observer)
    {
        OIC_LOG(INFO, TAG, "There is an observer associated with the response token");
        if(responseInfo->result == CA_EMPTY)
        {
            OIC_LOG(INFO, TAG, "Receiving A ACK/RESET for this token");
            if(responseInfo->info.type == CA_MSG_RESET)
            {
                OIC_LOG(INFO, TAG, "This is a RESET");
                OCStackFeedBack(responseInfo->info.token, responseInfo->info.tokenLength,
                        OC_OBSERVER_NOT_INTERESTED);
            }
            else if(responseInfo->info.type == CA_MSG_ACKNOWLEDGE)
            {
                OIC_LOG(INFO, TAG, "This is a pure ACK");
                OCStackFeedBack(responseInfo->info.token, responseInfo->info.tokenLength,
                        OC_OBSERVER_STILL_INTERESTED);
            }
        }
        else if(responseInfo->result == CA_RETRANSMIT_TIMEOUT)
        {
            OIC_LOG(INFO, TAG, "Receiving Time Out for an observer");
            OCStackFeedBack(responseInfo->info.token, responseInfo->info.tokenLength,
                    OC_OBSERVER_FAILED_COMM);
        }
        return;
    }

    if(!cbNode && !observer)
    {
        if(myStackMode == OC_CLIENT || myStackMode == OC_CLIENT_SERVER
           || myStackMode == OC_GATEWAY)
        {
            OIC_LOG(INFO, TAG, "This is a client, but no cbNode was found for token");
            if(responseInfo->result == CA_EMPTY)
            {
                OIC_LOG(INFO, TAG, "Receiving CA_EMPTY in the ocstack");
            }
            else
            {
                OIC_LOG(INFO, TAG, "Received a message without callbacks. Sending RESET");
                SendDirectStackResponse(endPoint, responseInfo->info.messageId, CA_EMPTY,
                                        CA_MSG_RESET, 0, NULL, NULL, 0, NULL, CA_RESPONSE_FOR_RES);
            }
        }

        if(myStackMode == OC_SERVER || myStackMode == OC_CLIENT_SERVER
           || myStackMode == OC_GATEWAY)
        {
            OIC_LOG(INFO, TAG, "This is a server, but no observer was found for token");
            if (responseInfo->info.type == CA_MSG_ACKNOWLEDGE)
            {
                OIC_LOG_V(INFO, TAG, "Received ACK at server for messageId : %d",
                                            responseInfo->info.messageId);
            }
            if (responseInfo->info.type == CA_MSG_RESET)
            {
                OIC_LOG_V(INFO, TAG, "Received RESET at server for messageId : %d",
                                            responseInfo->info.messageId);
            }
        }

        return;
    }

    OIC_LOG(INFO, TAG, "Exit OCHandleResponse");
}

void HandleCAResponses(const CAEndpoint_t* endPoint, const CAResponseInfo_t* responseInfo)
{
    VERIFY_NON_NULL_NR(endPoint, FATAL);
    VERIFY_NON_NULL_NR(responseInfo, FATAL);

    OIC_LOG(INFO, TAG, "Enter HandleCAResponses");

#if defined (ROUTING_GATEWAY) || defined (ROUTING_EP)
#ifdef ROUTING_GATEWAY
    bool needRIHandling = false;
    /*
     * Routing manager is going to update either of endpoint or response or both.
     * This typecasting is done to avoid unnecessary duplication of Endpoint and responseInfo
     * RM can update "routeData" option in endPoint so that future RI requests can be sent to proper
     * destination.
     */
    OCStackResult ret = RMHandleResponse((CAResponseInfo_t *)responseInfo, (CAEndpoint_t *)endPoint,
                                         &needRIHandling);
    if(ret != OC_STACK_OK || !needRIHandling)
    {
        OIC_LOG_V(INFO, TAG, "Routing status![%d]. Not forwarding to RI", ret);
        return;
    }
#endif

    /*
     * Put source in sender endpoint so that the next packet from application can be routed to
     * proper destination and remove "RM" coap header option before passing request / response to
     * RI as this option will make no sense to either RI or application.
     */
    RMUpdateInfo((CAHeaderOption_t **) &(responseInfo->info.options),
                 (uint8_t *) &(responseInfo->info.numOptions),
                 (CAEndpoint_t *) endPoint);
#endif

    OCHandleResponse(endPoint, responseInfo);

    OIC_LOG(INFO, TAG, "Exit HandleCAResponses");
}

/*
 * This function handles error response from CA
 * code shall be added to handle the errors
 */
void HandleCAErrorResponse(const CAEndpoint_t *endPoint, const CAErrorInfo_t *errorInfo)
{
    OIC_LOG(INFO, TAG, "Enter HandleCAErrorResponse");

    if (NULL == endPoint)
    {
        OIC_LOG(ERROR, TAG, "endPoint is NULL");
        return;
    }

    if (NULL == errorInfo)
    {
        OIC_LOG(ERROR, TAG, "errorInfo is NULL");
        return;
    }

    ClientCB *cbNode = GetClientCB(errorInfo->info.token,
                                   errorInfo->info.tokenLength, NULL, NULL);
    if (cbNode)
    {
        OCClientResponse response = { .devAddr = { .adapter = OC_DEFAULT_ADAPTER } };
        CopyEndpointToDevAddr(endPoint, &response.devAddr);
        FixUpClientResponse(&response);
        response.resourceUri = errorInfo->info.resourceUri;
        memcpy(response.identity.id, errorInfo->info.identity.id,
               sizeof (response.identity.id));
        response.identity.id_length = errorInfo->info.identity.id_length;
        response.result = CAResultToOCStackResult(errorInfo->result);

        cbNode->callBack(cbNode->context, cbNode->handle, &response);
        FindAndDeleteClientCB(cbNode);
    }

    OIC_LOG(INFO, TAG, "Exit HandleCAErrorResponse");
}

/*
 * This function sends out Direct Stack Responses. These are responses that are not coming
 * from the application entity handler. These responses have no payload and are usually ACKs,
 * RESETs or some error conditions that were caught by the stack.
 */
OCStackResult SendDirectStackResponse(const CAEndpoint_t* endPoint, const uint16_t coapID,
        const CAResponseResult_t responseResult, const CAMessageType_t type,
        const uint8_t numOptions, const CAHeaderOption_t *options,
        CAToken_t token, uint8_t tokenLength, const char *resourceUri,
        CADataType_t dataType)
{
    OIC_LOG(DEBUG, TAG, "Entering SendDirectStackResponse");
    CAResponseInfo_t respInfo = {
        .result = responseResult
    };
    respInfo.info.messageId = coapID;
    respInfo.info.numOptions = numOptions;

    if (respInfo.info.numOptions)
    {
        respInfo.info.options =
            (CAHeaderOption_t *)OICCalloc(respInfo.info.numOptions, sizeof(CAHeaderOption_t));
        memcpy (respInfo.info.options, options,
                sizeof(CAHeaderOption_t) * respInfo.info.numOptions);

    }

    respInfo.info.payload = NULL;
    respInfo.info.token = token;
    respInfo.info.tokenLength = tokenLength;
    respInfo.info.type = type;
    respInfo.info.resourceUri = OICStrdup (resourceUri);
    respInfo.info.acceptFormat = CA_FORMAT_UNDEFINED;
    respInfo.info.dataType = dataType;

#if defined (ROUTING_GATEWAY) || defined (ROUTING_EP)
    // Add the destination to route option from the endpoint->routeData.
    bool doPost = false;
    OCStackResult result = RMAddInfo(endPoint->routeData, &respInfo, false, &doPost);
    if(OC_STACK_OK != result)
    {
        OIC_LOG_V(ERROR, TAG, "Add routing option failed [%d]", result);
        return result;
    }
    if (doPost)
    {
        OIC_LOG(DEBUG, TAG, "Sending a POST message for EMPTY ACK in Client Mode");
        CARequestInfo_t reqInfo = {.method = CA_POST };
        /* The following initialization is not done in a single initializer block as in
         * arduino, .c file is compiled as .cpp and moves it from C99 to C++11.  The latter
         * does not have designated initalizers. This is a work-around for now.
         */
        reqInfo.info.type = CA_MSG_NONCONFIRM;
        reqInfo.info.messageId = coapID;
        reqInfo.info.tokenLength = tokenLength;
        reqInfo.info.token = token;
        reqInfo.info.numOptions = respInfo.info.numOptions;
        reqInfo.info.payload = NULL;
        reqInfo.info.resourceUri = OICStrdup (OC_RSRVD_GATEWAY_URI);
        if (reqInfo.info.numOptions)
        {
            reqInfo.info.options =
                (CAHeaderOption_t *)OICCalloc(reqInfo.info.numOptions, sizeof(CAHeaderOption_t));
            if (NULL == reqInfo.info.options)
            {
                OIC_LOG(ERROR, TAG, "Calloc failed");
                return OC_STACK_NO_MEMORY;
            }
            memcpy (reqInfo.info.options, respInfo.info.options,
                    sizeof(CAHeaderOption_t) * reqInfo.info.numOptions);

        }
        CAResult_t caResult = CASendRequest(endPoint, &reqInfo);
        OICFree (reqInfo.info.resourceUri);
        OICFree (reqInfo.info.options);
        OICFree (respInfo.info.resourceUri);
        OICFree (respInfo.info.options);
        if (CA_STATUS_OK != caResult)
        {
            OIC_LOG(ERROR, TAG, "CASendRequest error");
            return CAResultToOCResult(caResult);
        }
    }
    else
#endif
    {
        CAResult_t caResult = CASendResponse(endPoint, &respInfo);

        // resourceUri in the info field is cloned in the CA layer and
        // thus ownership is still here.
        OICFree (respInfo.info.resourceUri);
        OICFree (respInfo.info.options);
        if(CA_STATUS_OK != caResult)
        {
            OIC_LOG(ERROR, TAG, "CASendResponse error");
            return CAResultToOCResult(caResult);
        }
    }
    OIC_LOG(DEBUG, TAG, "Exit SendDirectStackResponse");
    return OC_STACK_OK;
}

OCStackResult HandleStackRequests(OCServerProtocolRequest * protocolRequest)
{
    OIC_LOG(INFO, TAG, "Entering HandleStackRequests (OCStack Layer)");
    OCStackResult result = OC_STACK_ERROR;
    if(!protocolRequest)
    {
        OIC_LOG(ERROR, TAG, "protocolRequest is NULL");
        return OC_STACK_INVALID_PARAM;
    }

    OCServerRequest * request = GetServerRequestUsingToken(protocolRequest->requestToken,
            protocolRequest->tokenLength);
    if(!request)
    {
        OIC_LOG(INFO, TAG, "This is a new Server Request");
        result = AddServerRequest(&request, protocolRequest->coapID,
                protocolRequest->delayedResNeeded, 0, protocolRequest->method,
                protocolRequest->numRcvdVendorSpecificHeaderOptions,
                protocolRequest->observationOption, protocolRequest->qos,
                protocolRequest->query, protocolRequest->rcvdVendorSpecificHeaderOptions,
                protocolRequest->payload, protocolRequest->requestToken,
                protocolRequest->tokenLength, protocolRequest->resourceUrl,
                protocolRequest->reqTotalSize, protocolRequest->acceptFormat,
                &protocolRequest->devAddr);
        if (OC_STACK_OK != result)
        {
            OIC_LOG(ERROR, TAG, "Error adding server request");
            return result;
        }

        if(!request)
        {
            OIC_LOG(ERROR, TAG, "Out of Memory");
            return OC_STACK_NO_MEMORY;
        }

        if(!protocolRequest->reqMorePacket)
        {
            request->requestComplete = 1;
        }
    }
    else
    {
        OIC_LOG(INFO, TAG, "This is either a repeated or blocked Server Request");
    }

    if(request->requestComplete)
    {
        OIC_LOG(INFO, TAG, "This Server Request is complete");
        ResourceHandling resHandling = OC_RESOURCE_VIRTUAL;
        OCResource *resource = NULL;
        result = DetermineResourceHandling (request, &resHandling, &resource);
        if (result == OC_STACK_OK)
        {
            result = ProcessRequest(resHandling, resource, request);
        }
    }
    else
    {
        OIC_LOG(INFO, TAG, "This Server Request is incomplete");
        result = OC_STACK_CONTINUE;
    }
    return result;
}

void OCHandleRequests(const CAEndpoint_t* endPoint, const CARequestInfo_t* requestInfo)
{
    OIC_LOG(DEBUG, TAG, "Enter OCHandleRequests");

#ifdef TCP_ADAPTER
    if (requestInfo->info.resourceUri &&
            strcmp(requestInfo->info.resourceUri, KEEPALIVE_RESOURCE_URI) == 0)
    {
        HandleKeepAliveRequest(endPoint, requestInfo);
        return;
    }
#endif

    OCStackResult requestResult = OC_STACK_ERROR;

    if(myStackMode == OC_CLIENT)
    {
        //TODO: should the client be responding to requests?
        return;
    }

    OCServerProtocolRequest serverRequest = {0};

    OIC_LOG_V(INFO, TAG, "Endpoint URI : %s", requestInfo->info.resourceUri);

    char * uriWithoutQuery = NULL;
    char * query  = NULL;

    requestResult = getQueryFromUri(requestInfo->info.resourceUri, &query, &uriWithoutQuery);

    if (requestResult != OC_STACK_OK || !uriWithoutQuery)
    {
        OIC_LOG_V(ERROR, TAG, "getQueryFromUri() failed with OC error code %d\n", requestResult);
        return;
    }
    OIC_LOG_V(INFO, TAG, "URI without query: %s", uriWithoutQuery);
    OIC_LOG_V(INFO, TAG, "Query : %s", query);

    if(strlen(uriWithoutQuery) < MAX_URI_LENGTH)
    {
        OICStrcpy(serverRequest.resourceUrl, sizeof(serverRequest.resourceUrl), uriWithoutQuery);
        OICFree(uriWithoutQuery);
    }
    else
    {
        OIC_LOG(ERROR, TAG, "URI length exceeds MAX_URI_LENGTH.");
        OICFree(uriWithoutQuery);
        OICFree(query);
        return;
    }

    if(query)
    {
        if(strlen(query) < MAX_QUERY_LENGTH)
        {
            OICStrcpy(serverRequest.query, sizeof(serverRequest.query), query);
            OICFree(query);
        }
        else
        {
            OIC_LOG(ERROR, TAG, "Query length exceeds MAX_QUERY_LENGTH.");
            OICFree(query);
            return;
        }
    }

    if ((requestInfo->info.payload) && (0 < requestInfo->info.payloadSize))
    {
        serverRequest.reqTotalSize = requestInfo->info.payloadSize;
        serverRequest.payload = (uint8_t *) OICMalloc(requestInfo->info.payloadSize);
        if (!serverRequest.payload)
        {
            OIC_LOG(ERROR, TAG, "Allocation for payload failed.");
            return;
        }
        memcpy (serverRequest.payload, requestInfo->info.payload,
                requestInfo->info.payloadSize);
    }
    else
    {
        serverRequest.reqTotalSize = 0;
    }

    switch (requestInfo->method)
    {
        case CA_GET:
            serverRequest.method = OC_REST_GET;
            break;
        case CA_PUT:
            serverRequest.method = OC_REST_PUT;
            break;
        case CA_POST:
            serverRequest.method = OC_REST_POST;
            break;
        case CA_DELETE:
            serverRequest.method = OC_REST_DELETE;
            break;
        default:
            OIC_LOG_V(ERROR, TAG, "Received CA method %d not supported", requestInfo->method);
            SendDirectStackResponse(endPoint, requestInfo->info.messageId, CA_BAD_REQ,
                        requestInfo->info.type, requestInfo->info.numOptions,
                        requestInfo->info.options, requestInfo->info.token,
                        requestInfo->info.tokenLength, requestInfo->info.resourceUri,
                        CA_RESPONSE_DATA);
            OICFree(serverRequest.payload);
            return;
    }

    OIC_LOG_BUFFER(INFO, TAG, (const uint8_t *)requestInfo->info.token,
            requestInfo->info.tokenLength);

    serverRequest.tokenLength = requestInfo->info.tokenLength;
    if (serverRequest.tokenLength) {
        // Non empty token
        serverRequest.requestToken = (CAToken_t)OICMalloc(requestInfo->info.tokenLength);

        if (!serverRequest.requestToken)
        {
            OIC_LOG(FATAL, TAG, "Allocation for token failed.");
            SendDirectStackResponse(endPoint, requestInfo->info.messageId, CA_INTERNAL_SERVER_ERROR,
                    requestInfo->info.type, requestInfo->info.numOptions,
                    requestInfo->info.options, requestInfo->info.token,
                    requestInfo->info.tokenLength, requestInfo->info.resourceUri,
                    CA_RESPONSE_DATA);
            OICFree(serverRequest.payload);
            return;
        }
        memcpy(serverRequest.requestToken, requestInfo->info.token, requestInfo->info.tokenLength);
    }

    switch (requestInfo->info.acceptFormat)
    {
        case CA_FORMAT_APPLICATION_CBOR:
            serverRequest.acceptFormat = OC_FORMAT_CBOR;
            break;
        case CA_FORMAT_UNDEFINED:
            serverRequest.acceptFormat = OC_FORMAT_UNDEFINED;
            break;
        default:
            serverRequest.acceptFormat = OC_FORMAT_UNSUPPORTED;
    }

    if (requestInfo->info.type == CA_MSG_CONFIRM)
    {
        serverRequest.qos = OC_HIGH_QOS;
    }
    else
    {
        serverRequest.qos = OC_LOW_QOS;
    }
    // CA does not need the following field
    // Are we sure CA does not need them? how is it responding to multicast
    serverRequest.delayedResNeeded = 0;

    serverRequest.coapID = requestInfo->info.messageId;

    CopyEndpointToDevAddr(endPoint, &serverRequest.devAddr);

    // copy vendor specific header options
    uint8_t tempNum = (requestInfo->info.numOptions);

    // Assume no observation requested and it is a pure GET.
    // If obs registration/de-registration requested it'll be fetched from the
    // options in GetObserveHeaderOption()
    serverRequest.observationOption = OC_OBSERVE_NO_OPTION;

    GetObserveHeaderOption(&serverRequest.observationOption, requestInfo->info.options, &tempNum);
    if (requestInfo->info.numOptions > MAX_HEADER_OPTIONS)
    {
        OIC_LOG(ERROR, TAG,
                "The request info numOptions is greater than MAX_HEADER_OPTIONS");
        SendDirectStackResponse(endPoint, requestInfo->info.messageId, CA_BAD_OPT,
                requestInfo->info.type, requestInfo->info.numOptions,
                requestInfo->info.options, requestInfo->info.token,
                requestInfo->info.tokenLength, requestInfo->info.resourceUri,
                CA_RESPONSE_DATA);
        OICFree(serverRequest.payload);
        OICFree(serverRequest.requestToken);
        return;
    }
    serverRequest.numRcvdVendorSpecificHeaderOptions = tempNum;
    if (serverRequest.numRcvdVendorSpecificHeaderOptions)
    {
        memcpy (&(serverRequest.rcvdVendorSpecificHeaderOptions), requestInfo->info.options,
            sizeof(CAHeaderOption_t)*tempNum);
    }

    requestResult = HandleStackRequests (&serverRequest);

    // Send ACK to client as precursor to slow response
    if (requestResult == OC_STACK_SLOW_RESOURCE)
    {
        if (requestInfo->info.type == CA_MSG_CONFIRM)
        {
            SendDirectStackResponse(endPoint, requestInfo->info.messageId, CA_EMPTY,
                                    CA_MSG_ACKNOWLEDGE,0, NULL, NULL, 0, NULL,
                                    CA_RESPONSE_DATA);
        }
    }
    else if(!OCResultToSuccess(requestResult))
    {
        OIC_LOG_V(ERROR, TAG, "HandleStackRequests failed. error: %d", requestResult);

        CAResponseResult_t stackResponse =
            OCToCAStackResult(requestResult, serverRequest.method);

        SendDirectStackResponse(endPoint, requestInfo->info.messageId, stackResponse,
                requestInfo->info.type, requestInfo->info.numOptions,
                requestInfo->info.options, requestInfo->info.token,
                requestInfo->info.tokenLength, requestInfo->info.resourceUri,
                CA_RESPONSE_DATA);
    }
    // requestToken is fed to HandleStackRequests, which then goes to AddServerRequest.
    // The token is copied in there, and is thus still owned by this function.
    OICFree(serverRequest.payload);
    OICFree(serverRequest.requestToken);
    OIC_LOG(INFO, TAG, "Exit OCHandleRequests");
}

//This function will be called back by CA layer when a request is received
void HandleCARequests(const CAEndpoint_t* endPoint, const CARequestInfo_t* requestInfo)
{
    OIC_LOG(INFO, TAG, "Enter HandleCARequests");
    if(!endPoint)
    {
        OIC_LOG(ERROR, TAG, "endPoint is NULL");
        return;
    }

    if(!requestInfo)
    {
        OIC_LOG(ERROR, TAG, "requestInfo is NULL");
        return;
    }

#if defined (ROUTING_GATEWAY) || defined (ROUTING_EP)
#ifdef ROUTING_GATEWAY
    bool needRIHandling = false;
    bool isEmptyMsg = false;
    /*
     * Routing manager is going to update either of endpoint or request or both.
     * This typecasting is done to avoid unnecessary duplication of Endpoint and requestInfo
     * RM can update "routeData" option in endPoint so that future RI requests can be sent to proper
     * destination. It can also remove "RM" coap header option before passing request / response to
     * RI as this option will make no sense to either RI or application.
     */
    OCStackResult ret = RMHandleRequest((CARequestInfo_t *)requestInfo, (CAEndpoint_t *)endPoint,
                                        &needRIHandling, &isEmptyMsg);
    if(OC_STACK_OK != ret || !needRIHandling)
    {
        OIC_LOG_V(INFO, TAG, "Routing status![%d]. Not forwarding to RI", ret);
        return;
    }
#endif

    /*
     * Put source in sender endpoint so that the next packet from application can be routed to
     * proper destination and remove RM header option.
     */
    RMUpdateInfo((CAHeaderOption_t **) &(requestInfo->info.options),
                 (uint8_t *) &(requestInfo->info.numOptions),
                 (CAEndpoint_t *) endPoint);

#ifdef ROUTING_GATEWAY
    if (isEmptyMsg)
    {
        /*
         * In Gateways, the MSGType in route option is used to check if the actual
         * response is EMPTY message(4 bytes CoAP Header).  In case of Client, the
         * EMPTY response is sent in the form of POST request which need to be changed
         * to a EMPTY response by RM.  This translation is done in this part of the code.
         */
        OIC_LOG(INFO, TAG, "This is a Empty response from the Client");
        CAResponseInfo_t respInfo = {.result = CA_EMPTY,
                                     .info.messageId = requestInfo->info.messageId,
                                     .info.type = CA_MSG_ACKNOWLEDGE};
        OCHandleResponse(endPoint, &respInfo);
    }
    else
#endif
#endif
    {
        // Normal handling of the packet
        OCHandleRequests(endPoint, requestInfo);
    }
    OIC_LOG(INFO, TAG, "Exit HandleCARequests");
}

bool validatePlatformInfo(OCPlatformInfo info)
{

    if (!info.platformID)
    {
        OIC_LOG(ERROR, TAG, "No platform ID found.");
        return false;
    }

    if (info.manufacturerName)
    {
        size_t lenManufacturerName = strlen(info.manufacturerName);

        if(lenManufacturerName == 0 || lenManufacturerName > MAX_MANUFACTURER_NAME_LENGTH)
        {
            OIC_LOG(ERROR, TAG, "Manufacturer name fails length requirements.");
            return false;
        }
    }
    else
    {
        OIC_LOG(ERROR, TAG, "No manufacturer name present");
        return false;
    }

    if (info.manufacturerUrl)
    {
        if(strlen(info.manufacturerUrl) > MAX_MANUFACTURER_URL_LENGTH)
        {
            OIC_LOG(ERROR, TAG, "Manufacturer url fails length requirements.");
            return false;
        }
    }
    return true;
}

//-----------------------------------------------------------------------------
// Public APIs
//-----------------------------------------------------------------------------
#ifdef RA_ADAPTER
OCStackResult OCSetRAInfo(const OCRAInfo_t *raInfo)
{
    if (!raInfo           ||
        !raInfo->username ||
        !raInfo->hostname ||
        !raInfo->xmpp_domain)
    {

        return OC_STACK_INVALID_PARAM;
    }
    OCStackResult result = CAResultToOCResult(CASetRAInfo((const CARAInfo_t *) raInfo));
    gRASetInfo = (result == OC_STACK_OK)? true : false;

    return result;
}
#endif

OCStackResult OCInit(const char *ipAddr, uint16_t port, OCMode mode)
{
    (void) ipAddr;
    (void) port;
    return OCInit1(mode, OC_DEFAULT_FLAGS, OC_DEFAULT_FLAGS);
}

OCStackResult OCInit1(OCMode mode, OCTransportFlags serverFlags, OCTransportFlags clientFlags)
{
    if(stackState == OC_STACK_INITIALIZED)
    {
        OIC_LOG(INFO, TAG, "Subsequent calls to OCInit() without calling \
                OCStop() between them are ignored.");
        return OC_STACK_OK;
    }

#ifndef ROUTING_GATEWAY
    if (OC_GATEWAY == mode)
    {
        OIC_LOG(ERROR, TAG, "Routing Manager not supported");
        return OC_STACK_INVALID_PARAM;
    }
#endif

#ifdef RA_ADAPTER
    if(!gRASetInfo)
    {
        OIC_LOG(ERROR, TAG, "Need to call OCSetRAInfo before calling OCInit");
        return OC_STACK_ERROR;
    }
#endif

    OCStackResult result = OC_STACK_ERROR;
    OIC_LOG(INFO, TAG, "Entering OCInit");

    // Validate mode
    if (!((mode == OC_CLIENT) || (mode == OC_SERVER) || (mode == OC_CLIENT_SERVER)
        || (mode == OC_GATEWAY)))
    {
        OIC_LOG(ERROR, TAG, "Invalid mode");
        return OC_STACK_ERROR;
    }
    myStackMode = mode;

    if (mode == OC_CLIENT || mode == OC_CLIENT_SERVER || mode == OC_GATEWAY)
    {
        caglobals.client = true;
    }
    if (mode == OC_SERVER || mode == OC_CLIENT_SERVER || mode == OC_GATEWAY)
    {
        caglobals.server = true;
    }

    caglobals.serverFlags = (CATransportFlags_t)serverFlags;
    if (!(caglobals.serverFlags & CA_IPFAMILY_MASK))
    {
        caglobals.serverFlags = (CATransportFlags_t)(caglobals.serverFlags|CA_IPV4|CA_IPV6);
    }
    caglobals.clientFlags = (CATransportFlags_t)clientFlags;
    if (!(caglobals.clientFlags & CA_IPFAMILY_MASK))
    {
        caglobals.clientFlags = (CATransportFlags_t)(caglobals.clientFlags|CA_IPV4|CA_IPV6);
    }

    defaultDeviceHandler = NULL;
    defaultDeviceHandlerCallbackParameter = NULL;

    result = CAResultToOCResult(CAInitialize());
    VERIFY_SUCCESS(result, OC_STACK_OK);

    result = CAResultToOCResult(OCSelectNetwork());
    VERIFY_SUCCESS(result, OC_STACK_OK);

    switch (myStackMode)
    {
        case OC_CLIENT:
            CARegisterHandler(HandleCARequests, HandleCAResponses, HandleCAErrorResponse);
            result = CAResultToOCResult(CAStartDiscoveryServer());
            OIC_LOG(INFO, TAG, "Client mode: CAStartDiscoveryServer");
            break;
        case OC_SERVER:
            SRMRegisterHandler(HandleCARequests, HandleCAResponses, HandleCAErrorResponse);
            result = CAResultToOCResult(CAStartListeningServer());
            OIC_LOG(INFO, TAG, "Server mode: CAStartListeningServer");
            break;
        case OC_CLIENT_SERVER:
        case OC_GATEWAY:
            SRMRegisterHandler(HandleCARequests, HandleCAResponses, HandleCAErrorResponse);
            result = CAResultToOCResult(CAStartListeningServer());
            if(result == OC_STACK_OK)
            {
                result = CAResultToOCResult(CAStartDiscoveryServer());
            }
            break;
    }
    VERIFY_SUCCESS(result, OC_STACK_OK);

#ifdef TCP_ADAPTER
    CARegisterKeepAliveHandler(HandleKeepAliveConnCB);
#endif

#ifdef WITH_PRESENCE
    PresenceTimeOutSize = sizeof (PresenceTimeOut) / sizeof (PresenceTimeOut[0]) - 1;
#endif // WITH_PRESENCE

    //Update Stack state to initialized
    stackState = OC_STACK_INITIALIZED;

    // Initialize resource
    if(myStackMode != OC_CLIENT)
    {
        result = initResources();
    }

    // Initialize the SRM Policy Engine
    if(result == OC_STACK_OK)
    {
        result = SRMInitPolicyEngine();
        // TODO after BeachHead delivery: consolidate into single SRMInit()
    }
#if defined (ROUTING_GATEWAY) || defined (ROUTING_EP)
    RMSetStackMode(mode);
#ifdef ROUTING_GATEWAY
    if (OC_GATEWAY == myStackMode)
    {
        result = RMInitialize();
    }
#endif
#endif

#ifdef TCP_ADAPTER
    if (result == OC_STACK_OK)
    {
        result = InitializeKeepAlive(myStackMode);
    }
#endif

exit:
    if(result != OC_STACK_OK)
    {
        OIC_LOG(ERROR, TAG, "Stack initialization error");
        deleteAllResources();
        CATerminate();
        stackState = OC_STACK_UNINITIALIZED;
    }
    return result;
}

OCStackResult OCStop()
{
    OIC_LOG(INFO, TAG, "Entering OCStop");

    if (stackState == OC_STACK_UNINIT_IN_PROGRESS)
    {
        OIC_LOG(DEBUG, TAG, "Stack already stopping, exiting");
        return OC_STACK_OK;
    }
    else if (stackState != OC_STACK_INITIALIZED)
    {
        OIC_LOG(ERROR, TAG, "Stack not initialized");
        return OC_STACK_ERROR;
    }

    stackState = OC_STACK_UNINIT_IN_PROGRESS;

#ifdef WITH_PRESENCE
    // Ensure that the TTL associated with ANY and ALL presence notifications originating from
    // here send with the code "OC_STACK_PRESENCE_STOPPED" result.
    presenceResource.presenceTTL = 0;
#endif // WITH_PRESENCE

#ifdef ROUTING_GATEWAY
    if (OC_GATEWAY == myStackMode)
    {
        RMTerminate();
    }
#endif

#ifdef TCP_ADAPTER
    TerminateKeepAlive(myStackMode);
#endif

    // Free memory dynamically allocated for resources
    deleteAllResources();
    DeleteDeviceInfo();
    DeletePlatformInfo();
    CATerminate();
    // Remove all observers
    DeleteObserverList();
    // Remove all the client callbacks
    DeleteClientCBList();

    // De-init the SRM Policy Engine
    // TODO after BeachHead delivery: consolidate into single SRMDeInit()
    SRMDeInitPolicyEngine();


    stackState = OC_STACK_UNINITIALIZED;
    return OC_STACK_OK;
}

OCStackResult OCStartMulticastServer()
{
    if(stackState != OC_STACK_INITIALIZED)
    {
        OIC_LOG(ERROR, TAG, "OCStack is not initalized. Cannot start multicast server.");
        return OC_STACK_ERROR;
    }
    CAResult_t ret = CAStartListeningServer();
    if (CA_STATUS_OK != ret)
    {
        OIC_LOG_V(ERROR, TAG, "Failed starting listening server: %d", ret);
        return OC_STACK_ERROR;
    }
    return OC_STACK_OK;
}

OCStackResult OCStopMulticastServer()
{
    CAResult_t ret = CAStopListeningServer();
    if (CA_STATUS_OK != ret)
    {
        OIC_LOG_V(ERROR, TAG, "Failed stopping listening server: %d", ret);
        return OC_STACK_ERROR;
    }
    return OC_STACK_OK;
}

CAMessageType_t qualityOfServiceToMessageType(OCQualityOfService qos)
{
    switch (qos)
    {
        case OC_HIGH_QOS:
            return CA_MSG_CONFIRM;
        case OC_LOW_QOS:
        case OC_MEDIUM_QOS:
        case OC_NA_QOS:
        default:
            return CA_MSG_NONCONFIRM;
    }
}

/**
 *  A request uri consists of the following components in order:
 *                              example
 *  optionally one of
 *      CoAP over UDP prefix    "coap://"
 *      CoAP over TCP prefix    "coap+tcp://"
 *  optionally one of
 *      IPv6 address            "[1234::5678]"
 *      IPv4 address            "192.168.1.1"
 *  optional port               ":5683"
 *  resource uri                "/oc/core..."
 *
 *  for PRESENCE requests, extract resource type.
 */
static OCStackResult ParseRequestUri(const char *fullUri,
                                        OCTransportAdapter adapter,
                                        OCTransportFlags flags,
                                        OCDevAddr **devAddr,
                                        char **resourceUri,
                                        char **resourceType)
{
    VERIFY_NON_NULL(fullUri, FATAL, OC_STACK_INVALID_CALLBACK);

    OCStackResult result = OC_STACK_OK;
    OCDevAddr *da = NULL;
    char *colon = NULL;
    char *end;

    // provide defaults for all returned values
    if (devAddr)
    {
        *devAddr = NULL;
    }
    if (resourceUri)
    {
        *resourceUri = NULL;
    }
    if (resourceType)
    {
        *resourceType = NULL;
    }

    // delimit url prefix, if any
    const char *start = fullUri;
    char *slash2 = strstr(start, "//");
    if (slash2)
    {
        start = slash2 + 2;
    }
    char *slash = strchr(start, '/');
    if (!slash)
    {
        return OC_STACK_INVALID_URI;
    }

    // process url scheme
    size_t prefixLen = slash2 - fullUri;
    bool istcp = false;
    if (prefixLen)
    {
        if ((prefixLen == sizeof(COAP_TCP) - 1) && (!strncmp(fullUri, COAP_TCP, prefixLen)))
        {
            istcp = true;
        }
    }

    // TODO: this logic should come in with unit tests exercising the various strings
    // processs url prefix, if any
    size_t urlLen = slash - start;
    // port
    uint16_t port = 0;
    size_t len = 0;
    if (urlLen && devAddr)
    {   // construct OCDevAddr
        if (start[0] == '[')
        {   // ipv6 address
            char *close = strchr(++start, ']');
            if (!close || close > slash)
            {
                return OC_STACK_INVALID_URI;
            }
            end = close;
            if (close[1] == ':')
            {
                colon = close + 1;
            }

            if (istcp)
            {
                adapter = (OCTransportAdapter)(adapter | OC_ADAPTER_TCP);
            }
            else
            {
                adapter = (OCTransportAdapter)(adapter | OC_ADAPTER_IP);
            }
            flags = (OCTransportFlags)(flags | OC_IP_USE_V6);
        }
        else
        {
            char *dot = strchr(start, '.');
            if (dot && dot < slash)
            {   // ipv4 address
                colon = strchr(start, ':');
                end = (colon && colon < slash) ? colon : slash;

                if (istcp)
                {
                    // coap over tcp
                    adapter = (OCTransportAdapter)(adapter | OC_ADAPTER_TCP);
                }
                else
                {
                    adapter = (OCTransportAdapter)(adapter | OC_ADAPTER_IP);
                }
                flags = (OCTransportFlags)(flags | OC_IP_USE_V4);
            }
            else
            {   // MAC address
                end = slash;
            }
        }
        len = end - start;
        if (len >= sizeof(da->addr))
        {
            return OC_STACK_INVALID_URI;
        }
        // collect port, if any
        if (colon && colon < slash)
        {
            for (colon++; colon < slash; colon++)
            {
                char c = colon[0];
                if (c < '0' || c > '9')
                {
                    return OC_STACK_INVALID_URI;
                }
                port = 10 * port + c - '0';
            }
        }

        len = end - start;
        if (len >= sizeof(da->addr))
        {
            return OC_STACK_INVALID_URI;
        }

        da = (OCDevAddr *)OICCalloc(sizeof (OCDevAddr), 1);
        if (!da)
        {
            return OC_STACK_NO_MEMORY;
        }
        OICStrcpyPartial(da->addr, sizeof(da->addr), start, len);
        da->port = port;
        da->adapter = adapter;
        da->flags = flags;
        if (!strncmp(fullUri, "coaps:", 6))
        {
            da->flags = (OCTransportFlags)(da->flags|CA_SECURE);
        }
        *devAddr = da;
    }

    // process resource uri, if any
    if (slash)
    {   // request uri and query
        size_t ulen = strlen(slash); // resource uri length
        size_t tlen = 0;      // resource type length
        char *type = NULL;

        static const char strPresence[] = "/oic/ad?rt=";
        static const size_t lenPresence = sizeof(strPresence) - 1;
        if (!strncmp(slash, strPresence, lenPresence))
        {
            type = slash + lenPresence;
            tlen = ulen - lenPresence;
        }
        // resource uri
        if (resourceUri)
        {
            *resourceUri = (char *)OICMalloc(ulen + 1);
            if (!*resourceUri)
            {
                result = OC_STACK_NO_MEMORY;
                goto error;
            }
            strcpy(*resourceUri, slash);
        }
        // resource type
        if (type && resourceType)
        {
            *resourceType = (char *)OICMalloc(tlen + 1);
            if (!*resourceType)
            {
                result = OC_STACK_NO_MEMORY;
                goto error;
            }

            OICStrcpy(*resourceType, (tlen+1), type);
        }
    }

    return OC_STACK_OK;

error:
    // free all returned values
    if (devAddr)
    {
        OICFree(*devAddr);
    }
    if (resourceUri)
    {
        OICFree(*resourceUri);
    }
    if (resourceType)
    {
        OICFree(*resourceType);
    }
    return result;
}

static OCStackResult OCPreparePresence(CAEndpoint_t *endpoint,
                                        char *resourceUri, char **requestUri)
{
    char uri[CA_MAX_URI_LENGTH];

    FormCanonicalPresenceUri(endpoint, resourceUri, uri);

    *requestUri = OICStrdup(uri);
    if (!*requestUri)
    {
        return OC_STACK_NO_MEMORY;
    }

    return OC_STACK_OK;
}

/**
 * Discover or Perform requests on a specified resource
 */
OCStackResult OCDoResource(OCDoHandle *handle,
                            OCMethod method,
                            const char *requestUri,
                            const OCDevAddr *destination,
                            OCPayload* payload,
                            OCConnectivityType connectivityType,
                            OCQualityOfService qos,
                            OCCallbackData *cbData,
                            OCHeaderOption *options,
                            uint8_t numOptions)
{
    OIC_LOG(INFO, TAG, "Entering OCDoResource");

    // Validate input parameters
    VERIFY_NON_NULL(cbData, FATAL, OC_STACK_INVALID_CALLBACK);
    VERIFY_NON_NULL(cbData->cb, FATAL, OC_STACK_INVALID_CALLBACK);
    VERIFY_NON_NULL(requestUri , FATAL, OC_STACK_INVALID_URI);

    OCStackResult result = OC_STACK_ERROR;
    CAResult_t caResult;
    CAToken_t token = NULL;
    uint8_t tokenLength = CA_MAX_TOKEN_LEN;
    ClientCB *clientCB = NULL;
    OCDoHandle resHandle = NULL;
    CAEndpoint_t endpoint = {.adapter = CA_DEFAULT_ADAPTER};
    OCDevAddr tmpDevAddr = { OC_DEFAULT_ADAPTER };
    uint32_t ttl = 0;
    OCTransportAdapter adapter;
    OCTransportFlags flags;
    // the request contents are put here
    CARequestInfo_t requestInfo = {.method = CA_GET};
    // requestUri  will be parsed into the following three variables
    OCDevAddr *devAddr = NULL;
    char *resourceUri = NULL;
    char *resourceType = NULL;

    /*
     * Support original behavior with address on resourceUri argument.
     */
    adapter = (OCTransportAdapter)(connectivityType >> CT_ADAPTER_SHIFT);
    flags = (OCTransportFlags)(connectivityType & CT_MASK_FLAGS);

    result = ParseRequestUri(requestUri, adapter, flags, &devAddr, &resourceUri, &resourceType);

    if (result != OC_STACK_OK)
    {
        OIC_LOG_V(DEBUG, TAG, "Unable to parse uri: %s", requestUri);
        goto exit;
    }

    switch (method)
    {
    case OC_REST_GET:
    case OC_REST_OBSERVE:
    case OC_REST_OBSERVE_ALL:
    case OC_REST_CANCEL_OBSERVE:
        requestInfo.method = CA_GET;
        break;
    case OC_REST_PUT:
        requestInfo.method = CA_PUT;
        break;
    case OC_REST_POST:
        requestInfo.method = CA_POST;
        break;
    case OC_REST_DELETE:
        requestInfo.method = CA_DELETE;
        break;
    case OC_REST_DISCOVER:
        qos = OC_LOW_QOS;
        if (destination || devAddr)
        {
            requestInfo.isMulticast = false;
        }
        else
        {
            tmpDevAddr.adapter = adapter;
            tmpDevAddr.flags = flags;
            destination = &tmpDevAddr;
            requestInfo.isMulticast = true;
        }
        // CA_DISCOVER will become GET and isMulticast
        requestInfo.method = CA_GET;
        break;
#ifdef WITH_PRESENCE
    case OC_REST_PRESENCE:
        // Replacing method type with GET because "presence"
        // is a stack layer only implementation.
        requestInfo.method = CA_GET;
        break;
#endif
    default:
        result = OC_STACK_INVALID_METHOD;
        goto exit;
    }

    if (!devAddr && !destination)
    {
        OIC_LOG(DEBUG, TAG, "no devAddr and no destination");
        result = OC_STACK_INVALID_PARAM;
        goto exit;
    }

    /* If not original behavior, use destination argument */
    if (destination && !devAddr)
    {
        devAddr = (OCDevAddr *)OICMalloc(sizeof (OCDevAddr));
        if (!devAddr)
        {
            result = OC_STACK_NO_MEMORY;
            goto exit;
        }
        *devAddr = *destination;
    }

    resHandle = GenerateInvocationHandle();
    if (!resHandle)
    {
        result = OC_STACK_NO_MEMORY;
        goto exit;
    }

    caResult = CAGenerateToken(&token, tokenLength);
    if (caResult != CA_STATUS_OK)
    {
        OIC_LOG(ERROR, TAG, "CAGenerateToken error");
        result= OC_STACK_ERROR;
        goto exit;
    }

    // fill in request data
    requestInfo.info.type = qualityOfServiceToMessageType(qos);
    requestInfo.info.token = token;
    requestInfo.info.tokenLength = tokenLength;
    requestInfo.info.resourceUri = resourceUri;

    if ((method == OC_REST_OBSERVE) || (method == OC_REST_OBSERVE_ALL))
    {
        result = CreateObserveHeaderOption (&(requestInfo.info.options),
                                    options, numOptions, OC_OBSERVE_REGISTER);
        if (result != OC_STACK_OK)
        {
            goto exit;
        }
        requestInfo.info.numOptions = numOptions + 1;
    }
    else
    {
        requestInfo.info.numOptions = numOptions;
        requestInfo.info.options =
            (CAHeaderOption_t*) OICCalloc(numOptions, sizeof(CAHeaderOption_t));
        memcpy(requestInfo.info.options, (CAHeaderOption_t*)options,
               numOptions * sizeof(CAHeaderOption_t));
    }

    CopyDevAddrToEndpoint(devAddr, &endpoint);

    if(payload)
    {
        if((result =
            OCConvertPayload(payload, &requestInfo.info.payload, &requestInfo.info.payloadSize))
                != OC_STACK_OK)
        {
            OIC_LOG(ERROR, TAG, "Failed to create CBOR Payload");
            goto exit;
        }
        requestInfo.info.payloadFormat = CA_FORMAT_APPLICATION_CBOR;
    }
    else
    {
        requestInfo.info.payload = NULL;
        requestInfo.info.payloadSize = 0;
        requestInfo.info.payloadFormat = CA_FORMAT_UNDEFINED;
    }

    // prepare for response
#ifdef WITH_PRESENCE
    if (method == OC_REST_PRESENCE)
    {
        char *presenceUri = NULL;
        result = OCPreparePresence(&endpoint, resourceUri, &presenceUri);
        if (OC_STACK_OK != result)
        {
            goto exit;
        }

        // Assign full presence uri as coap://ip:port/oic/ad to add to callback list.
        // Presence notification will form a canonical uri to
        // look for callbacks into the application.
        resourceUri = presenceUri;
    }
#endif

    ttl = GetTicks(MAX_CB_TIMEOUT_SECONDS * MILLISECONDS_PER_SECOND);
    result = AddClientCB(&clientCB, cbData, token, tokenLength, &resHandle,
                            method, devAddr, resourceUri, resourceType, ttl);
    if (OC_STACK_OK != result)
    {
        goto exit;
    }

    devAddr = NULL;       // Client CB list entry now owns it
    resourceUri = NULL;   // Client CB list entry now owns it
    resourceType = NULL;  // Client CB list entry now owns it

    // send request
    result = OCSendRequest(&endpoint, &requestInfo);
    if (OC_STACK_OK != result)
    {
        goto exit;
    }

    if (handle)
    {
        *handle = resHandle;
    }

exit:
    if (result != OC_STACK_OK)
    {
        OIC_LOG(ERROR, TAG, "OCDoResource error");
        FindAndDeleteClientCB(clientCB);
        CADestroyToken(token);
        if (handle)
        {
            *handle = NULL;
        }
        OICFree(resHandle);
    }

    // This is the owner of the payload object, so we free it
    OCPayloadDestroy(payload);
    OICFree(requestInfo.info.payload);
    OICFree(devAddr);
    OICFree(resourceUri);
    OICFree(resourceType);
    OICFree(requestInfo.info.options);
    return result;
}

OCStackResult OCCancel(OCDoHandle handle, OCQualityOfService qos, OCHeaderOption * options,
        uint8_t numOptions)
{
    /*
     * This ftn is implemented one of two ways in the case of observation:
     *
     * 1. qos == OC_NON_CONFIRMABLE. When observe is unobserved..
     *      Remove the callback associated on client side.
     *      When the next notification comes in from server,
     *      reply with RESET message to server.
     *      Keep in mind that the server will react to RESET only
     *      if the last notification was sent as CON
     *
     * 2. qos == OC_CONFIRMABLE. When OCCancel is called,
     *      and it is associated with an observe request
     *      (i.e. ClientCB->method == OC_REST_OBSERVE || OC_REST_OBSERVE_ALL),
     *      Send CON Observe request to server with
     *      observe flag = OC_RESOURCE_OBSERVE_DEREGISTER.
     *      Remove the callback associated on client side.
     */
    OCStackResult ret = OC_STACK_OK;
    CAEndpoint_t endpoint = {.adapter = CA_DEFAULT_ADAPTER};
    CARequestInfo_t requestInfo = {.method = CA_GET};

    if(!handle)
    {
        return OC_STACK_INVALID_PARAM;
    }

    ClientCB *clientCB = GetClientCB(NULL, 0, handle, NULL);
    if (!clientCB)
    {
        OIC_LOG(ERROR, TAG, "Callback not found. Called OCCancel on same resource twice?");
        return OC_STACK_ERROR;
    }

    switch (clientCB->method)
    {
        case OC_REST_OBSERVE:
        case OC_REST_OBSERVE_ALL:

            OIC_LOG_V(INFO, TAG, "Canceling observation for resource %s", clientCB->requestUri);

            CopyDevAddrToEndpoint(clientCB->devAddr, &endpoint);

            if ((endpoint.adapter & CA_ADAPTER_IP) && qos != OC_HIGH_QOS)
            {
                FindAndDeleteClientCB(clientCB);
                break;
            }

            OIC_LOG(INFO, TAG, "Cancelling observation as CONFIRMABLE");

            requestInfo.info.type = qualityOfServiceToMessageType(qos);
            requestInfo.info.token = clientCB->token;
            requestInfo.info.tokenLength = clientCB->tokenLength;

            if (CreateObserveHeaderOption (&(requestInfo.info.options),
                    options, numOptions, OC_OBSERVE_DEREGISTER) != OC_STACK_OK)
            {
                return OC_STACK_ERROR;
            }
            requestInfo.info.numOptions = numOptions + 1;
            requestInfo.info.resourceUri = OICStrdup (clientCB->requestUri);


            ret = OCSendRequest(&endpoint, &requestInfo);

            if (requestInfo.info.options)
            {
                OICFree (requestInfo.info.options);
            }
            if (requestInfo.info.resourceUri)
            {
                OICFree (requestInfo.info.resourceUri);
            }

            break;

        case OC_REST_DISCOVER:
            OIC_LOG_V(INFO, TAG, "Cancelling discovery callback for resource %s",
                                           clientCB->requestUri);
            FindAndDeleteClientCB(clientCB);
            break;

#ifdef WITH_PRESENCE
        case OC_REST_PRESENCE:
            FindAndDeleteClientCB(clientCB);
            break;
#endif

        default:
            ret = OC_STACK_INVALID_METHOD;
            break;
    }

    return ret;
}

/**
 * @brief   Register Persistent storage callback.
 * @param   persistentStorageHandler [IN] Pointers to open, read, write, close & unlink handlers.
 * @return
 *     OC_STACK_OK    - No errors; Success
 *     OC_STACK_INVALID_PARAM - Invalid parameter
 */
OCStackResult OCRegisterPersistentStorageHandler(OCPersistentStorage* persistentStorageHandler)
{
    OIC_LOG(INFO, TAG, "RegisterPersistentStorageHandler !!");
    if(!persistentStorageHandler)
    {
        OIC_LOG(ERROR, TAG, "The persistent storage handler is invalid");
        return OC_STACK_INVALID_PARAM;
    }
    else
    {
        if( !persistentStorageHandler->open ||
                !persistentStorageHandler->close ||
                !persistentStorageHandler->read ||
                !persistentStorageHandler->unlink ||
                !persistentStorageHandler->write)
        {
            OIC_LOG(ERROR, TAG, "The persistent storage handler is invalid");
            return OC_STACK_INVALID_PARAM;
        }
    }
    return SRMRegisterPersistentStorageHandler(persistentStorageHandler);
}

#ifdef WITH_PRESENCE

OCStackResult OCProcessPresence()
{
    OCStackResult result = OC_STACK_OK;

    // the following line floods the log with messages that are irrelevant
    // to most purposes.  Uncomment as needed.
    //OIC_LOG(INFO, TAG, "Entering RequestPresence");
    ClientCB* cbNode = NULL;
    OCClientResponse clientResponse;
    OCStackApplicationResult cbResult = OC_STACK_DELETE_TRANSACTION;

    LL_FOREACH(cbList, cbNode)
    {
        if (OC_REST_PRESENCE != cbNode->method || !cbNode->presence)
        {
            continue;
        }

        uint32_t now = GetTicks(0);
        OIC_LOG_V(DEBUG, TAG, "this TTL level %d",
                                                cbNode->presence->TTLlevel);
        OIC_LOG_V(DEBUG, TAG, "current ticks %d", now);

        if (cbNode->presence->TTLlevel > PresenceTimeOutSize)
        {
            goto exit;
        }

        if (cbNode->presence->TTLlevel < PresenceTimeOutSize)
        {
            OIC_LOG_V(DEBUG, TAG, "timeout ticks %d",
                    cbNode->presence->timeOut[cbNode->presence->TTLlevel]);
        }
        if (cbNode->presence->TTLlevel >= PresenceTimeOutSize)
        {
            OIC_LOG(DEBUG, TAG, "No more timeout ticks");

            clientResponse.sequenceNumber = 0;
            clientResponse.result = OC_STACK_PRESENCE_TIMEOUT;
            clientResponse.devAddr = *cbNode->devAddr;
            FixUpClientResponse(&clientResponse);
            clientResponse.payload = NULL;

            // Increment the TTLLevel (going to a next state), so we don't keep
            // sending presence notification to client.
            cbNode->presence->TTLlevel++;
            OIC_LOG_V(DEBUG, TAG, "moving to TTL level %d",
                                        cbNode->presence->TTLlevel);

            cbResult = cbNode->callBack(cbNode->context, cbNode->handle, &clientResponse);
            if (cbResult == OC_STACK_DELETE_TRANSACTION)
            {
                FindAndDeleteClientCB(cbNode);
            }
        }

        if (now < cbNode->presence->timeOut[cbNode->presence->TTLlevel])
        {
            continue;
        }

        CAEndpoint_t endpoint = {.adapter = CA_DEFAULT_ADAPTER};
        CAInfo_t requestData = {.type = CA_MSG_CONFIRM};
        CARequestInfo_t requestInfo = {.method = CA_GET};

        OIC_LOG(DEBUG, TAG, "time to test server presence");

        CopyDevAddrToEndpoint(cbNode->devAddr, &endpoint);

        requestData.type = CA_MSG_NONCONFIRM;
        requestData.token = cbNode->token;
        requestData.tokenLength = cbNode->tokenLength;
        requestData.resourceUri = OC_RSRVD_PRESENCE_URI;
        requestInfo.method = CA_GET;
        requestInfo.info = requestData;

        result = OCSendRequest(&endpoint, &requestInfo);
        if (OC_STACK_OK != result)
        {
            goto exit;
        }

        cbNode->presence->TTLlevel++;
        OIC_LOG_V(DEBUG, TAG, "moving to TTL level %d", cbNode->presence->TTLlevel);
    }
exit:
    if (result != OC_STACK_OK)
    {
        OIC_LOG(ERROR, TAG, "OCProcessPresence error");
    }

    return result;
}
#endif // WITH_PRESENCE

OCStackResult OCProcess()
{
#ifdef WITH_PRESENCE
    OCProcessPresence();
#endif
    CAHandleRequestResponse();

#ifdef ROUTING_GATEWAY
    RMProcess();
#endif

#ifdef TCP_ADAPTER
    ProcessKeepAlive();
#endif
    return OC_STACK_OK;
}

#ifdef WITH_PRESENCE
OCStackResult OCStartPresence(const uint32_t ttl)
{
    uint8_t tokenLength = CA_MAX_TOKEN_LEN;
    OCChangeResourceProperty(
            &(((OCResource *)presenceResource.handle)->resourceProperties),
            OC_ACTIVE, 1);

    if (OC_MAX_PRESENCE_TTL_SECONDS < ttl)
    {
        presenceResource.presenceTTL = OC_MAX_PRESENCE_TTL_SECONDS;
        OIC_LOG(INFO, TAG, "Setting Presence TTL to max value");
    }
    else if (0 == ttl)
    {
        presenceResource.presenceTTL = OC_DEFAULT_PRESENCE_TTL_SECONDS;
        OIC_LOG(INFO, TAG, "Setting Presence TTL to default value");
    }
    else
    {
        presenceResource.presenceTTL = ttl;
    }
    OIC_LOG_V(DEBUG, TAG, "Presence TTL is %" PRIu32 " seconds", presenceResource.presenceTTL);

    if (OC_PRESENCE_UNINITIALIZED == presenceState)
    {
        presenceState = OC_PRESENCE_INITIALIZED;

        OCDevAddr devAddr = { OC_DEFAULT_ADAPTER };

        CAToken_t caToken = NULL;
        CAResult_t caResult = CAGenerateToken(&caToken, tokenLength);
        if (caResult != CA_STATUS_OK)
        {
            OIC_LOG(ERROR, TAG, "CAGenerateToken error");
            CADestroyToken(caToken);
            return OC_STACK_ERROR;
        }

        AddObserver(OC_RSRVD_PRESENCE_URI, NULL, 0, caToken, tokenLength,
                (OCResource *)presenceResource.handle, OC_LOW_QOS, OC_FORMAT_UNDEFINED, &devAddr);
        CADestroyToken(caToken);
    }

    // Each time OCStartPresence is called
    // a different random 32-bit integer number is used
    ((OCResource *)presenceResource.handle)->sequenceNum = OCGetRandom();

    return SendPresenceNotification(((OCResource *)presenceResource.handle)->rsrcType,
            OC_PRESENCE_TRIGGER_CREATE);
}

OCStackResult OCStopPresence()
{
    OCStackResult result = OC_STACK_ERROR;

    if(presenceResource.handle)
    {
        ((OCResource *)presenceResource.handle)->sequenceNum = OCGetRandom();

    // make resource inactive
    result = OCChangeResourceProperty(
            &(((OCResource *) presenceResource.handle)->resourceProperties),
            OC_ACTIVE, 0);
    }

    if(result != OC_STACK_OK)
    {
        OIC_LOG(ERROR, TAG,
                      "Changing the presence resource properties to ACTIVE not successful");
        return result;
    }

    return SendStopNotification();
}
#endif

OCStackResult OCSetDefaultDeviceEntityHandler(OCDeviceEntityHandler entityHandler,
                                            void* callbackParameter)
{
    defaultDeviceHandler = entityHandler;
    defaultDeviceHandlerCallbackParameter = callbackParameter;

    return OC_STACK_OK;
}

OCStackResult OCSetPlatformInfo(OCPlatformInfo platformInfo)
{
    OIC_LOG(INFO, TAG, "Entering OCSetPlatformInfo");

    if(myStackMode ==  OC_SERVER || myStackMode == OC_CLIENT_SERVER || myStackMode == OC_GATEWAY)
    {
        if (validatePlatformInfo(platformInfo))
        {
            return SavePlatformInfo(platformInfo);
        }
        else
        {
            return OC_STACK_INVALID_PARAM;
        }
    }
    else
    {
        return OC_STACK_ERROR;
    }
}

OCStackResult OCSetDeviceInfo(OCDeviceInfo deviceInfo)
{
    OIC_LOG(INFO, TAG, "Entering OCSetDeviceInfo");

    if (!deviceInfo.deviceName || deviceInfo.deviceName[0] == '\0')
    {
        OIC_LOG(ERROR, TAG, "Null or empty device name.");
        return OC_STACK_INVALID_PARAM;
    }

    if (deviceInfo.types)
    {
        OCStringLL *type =  deviceInfo.types;
        OCResource *resource = findResource((OCResource *) deviceResource);
        if (!resource)
        {
            return OC_STACK_INVALID_PARAM;
        }

        while (type)
        {
            OCBindResourceTypeToResource(deviceResource, type->value);
            type = type->next;
        }
    }
    return SaveDeviceInfo(deviceInfo);
}

OCStackResult OCCreateResource(OCResourceHandle *handle,
        const char *resourceTypeName,
        const char *resourceInterfaceName,
        const char *uri, OCEntityHandler entityHandler,
        void* callbackParam,
        uint8_t resourceProperties)
{

    OCResource *pointer = NULL;
    OCStackResult result = OC_STACK_ERROR;

    OIC_LOG(INFO, TAG, "Entering OCCreateResource");

    if(myStackMode == OC_CLIENT)
    {
        return OC_STACK_INVALID_PARAM;
    }
    // Validate parameters
    if(!uri || uri[0]=='\0' || strlen(uri)>=MAX_URI_LENGTH )
    {
        OIC_LOG(ERROR, TAG, "URI is empty or too long");
        return OC_STACK_INVALID_URI;
    }
    // Is it presented during resource discovery?
    if (!handle || !resourceTypeName || resourceTypeName[0] == '\0' )
    {
        OIC_LOG(ERROR, TAG, "Input parameter is NULL");
        return OC_STACK_INVALID_PARAM;
    }

    if (!resourceInterfaceName || strlen(resourceInterfaceName) == 0)
    {
        resourceInterfaceName = OC_RSRVD_INTERFACE_DEFAULT;
    }

#ifdef MQ_PUBLISHER
    resourceProperties = resourceProperties | OC_MQ_PUBLISHER;
#endif
    // Make sure resourceProperties bitmask has allowed properties specified
    if (resourceProperties
            > (OC_ACTIVE | OC_DISCOVERABLE | OC_OBSERVABLE | OC_SLOW | OC_SECURE |
               OC_EXPLICIT_DISCOVERABLE
#ifdef MQ_PUBLISHER
               | OC_MQ_PUBLISHER
#endif
#ifdef MQ_BROKER
               | OC_MQ_BROKER
#endif
               ))
    {
        OIC_LOG(ERROR, TAG, "Invalid property");
        return OC_STACK_INVALID_PARAM;
    }

    // If the headResource is NULL, then no resources have been created...
    pointer = headResource;
    if (pointer)
    {
        // At least one resources is in the resource list, so we need to search for
        // repeated URLs, which are not allowed.  If a repeat is found, exit with an error
        while (pointer)
        {
            if (strncmp(uri, pointer->uri, MAX_URI_LENGTH) == 0)
            {
                OIC_LOG_V(ERROR, TAG, "Resource %s already exists", uri);
                return OC_STACK_INVALID_PARAM;
            }
            pointer = pointer->next;
        }
    }
    // Create the pointer and insert it into the resource list
    pointer = (OCResource *) OICCalloc(1, sizeof(OCResource));
    if (!pointer)
    {
        result = OC_STACK_NO_MEMORY;
        goto exit;
    }
    pointer->sequenceNum = OC_OFFSET_SEQUENCE_NUMBER;

    insertResource(pointer);

    // Set the uri
    pointer->uri = OICStrdup(uri);
    if (!pointer->uri)
    {
        result = OC_STACK_NO_MEMORY;
        goto exit;
    }

    // Set properties.  Set OC_ACTIVE
    pointer->resourceProperties = (OCResourceProperty) (resourceProperties
            | OC_ACTIVE);

    // Add the resourcetype to the resource
    result = BindResourceTypeToResource(pointer, resourceTypeName);
    if (result != OC_STACK_OK)
    {
        OIC_LOG(ERROR, TAG, "Error adding resourcetype");
        goto exit;
    }

    // Add the resourceinterface to the resource
    result = BindResourceInterfaceToResource(pointer, resourceInterfaceName);
    if (result != OC_STACK_OK)
    {
        OIC_LOG(ERROR, TAG, "Error adding resourceinterface");
        goto exit;
    }

    // If an entity handler has been passed, attach it to the newly created
    // resource.  Otherwise, set the default entity handler.
    if (entityHandler)
    {
        pointer->entityHandler = entityHandler;
        pointer->entityHandlerCallbackParam = callbackParam;
    }
    else
    {
        pointer->entityHandler = defaultResourceEHandler;
        pointer->entityHandlerCallbackParam = NULL;
    }

    // Initialize a pointer indicating child resources in case of collection
    pointer->rsrcChildResourcesHead = NULL;

    *handle = pointer;
    result = OC_STACK_OK;

#ifdef WITH_PRESENCE
    if (presenceResource.handle)
    {
        ((OCResource *)presenceResource.handle)->sequenceNum = OCGetRandom();
        SendPresenceNotification(pointer->rsrcType, OC_PRESENCE_TRIGGER_CREATE);
    }
#endif
exit:
    if (result != OC_STACK_OK)
    {
        // Deep delete of resource and other dynamic elements that it contains
        deleteResource(pointer);
    }
    return result;
}

OCStackResult OCBindResource(
        OCResourceHandle collectionHandle, OCResourceHandle resourceHandle)
{
    OCResource *resource = NULL;
    OCChildResource *tempChildResource = NULL;
    OCChildResource *newChildResource = NULL;

    OIC_LOG(INFO, TAG, "Entering OCBindResource");

    // Validate parameters
    VERIFY_NON_NULL(collectionHandle, ERROR, OC_STACK_ERROR);
    VERIFY_NON_NULL(resourceHandle, ERROR, OC_STACK_ERROR);
    // Container cannot contain itself
    if (collectionHandle == resourceHandle)
    {
        OIC_LOG(ERROR, TAG, "Added handle equals collection handle");
        return OC_STACK_INVALID_PARAM;
    }

    // Use the handle to find the resource in the resource linked list
    resource = findResource((OCResource *) collectionHandle);
    if (!resource)
    {
        OIC_LOG(ERROR, TAG, "Collection handle not found");
        return OC_STACK_INVALID_PARAM;
    }

    // Look for an open slot to add add the child resource.
    // If found, add it and return success

    tempChildResource = resource->rsrcChildResourcesHead;

    while(resource->rsrcChildResourcesHead && tempChildResource->next)
    {
        // TODO: what if one of child resource was deregistered without unbinding?
        tempChildResource = tempChildResource->next;
    }

    // Do memory allocation for child resource
    newChildResource = (OCChildResource *) OICCalloc(1, sizeof(OCChildResource));
    if(!newChildResource)
    {
        OIC_LOG(ERROR, TAG, "Adding new child resource is failed due to memory allocation failure");
        return OC_STACK_ERROR;
    }

    newChildResource->rsrcResource = (OCResource *) resourceHandle;
    newChildResource->next = NULL;

    if(!resource->rsrcChildResourcesHead)
    {
        resource->rsrcChildResourcesHead = newChildResource;
    }
    else {
        tempChildResource->next = newChildResource;
    }

    OIC_LOG(INFO, TAG, "resource bound");

#ifdef WITH_PRESENCE
    if (presenceResource.handle)
    {
        ((OCResource *)presenceResource.handle)->sequenceNum = OCGetRandom();
        SendPresenceNotification(((OCResource *) resourceHandle)->rsrcType,
                OC_PRESENCE_TRIGGER_CHANGE);
    }
#endif

    return OC_STACK_OK;
}

OCStackResult OCUnBindResource(
        OCResourceHandle collectionHandle, OCResourceHandle resourceHandle)
{
    OCResource *resource = NULL;
    OCChildResource *tempChildResource = NULL;
    OCChildResource *tempLastChildResource = NULL;

    OIC_LOG(INFO, TAG, "Entering OCUnBindResource");

    // Validate parameters
    VERIFY_NON_NULL(collectionHandle, ERROR, OC_STACK_ERROR);
    VERIFY_NON_NULL(resourceHandle, ERROR, OC_STACK_ERROR);
    // Container cannot contain itself
    if (collectionHandle == resourceHandle)
    {
        OIC_LOG(ERROR, TAG, "removing handle equals collection handle");
        return OC_STACK_INVALID_PARAM;
    }

    // Use the handle to find the resource in the resource linked list
    resource = findResource((OCResource *) collectionHandle);
    if (!resource)
    {
        OIC_LOG(ERROR, TAG, "Collection handle not found");
        return OC_STACK_INVALID_PARAM;
    }

    // Look for an open slot to add add the child resource.
    // If found, add it and return success
    if(!resource->rsrcChildResourcesHead)
    {
        OIC_LOG(INFO, TAG, "resource not found in collection");

        // Unable to add resourceHandle, so return error
        return OC_STACK_ERROR;

    }

    tempChildResource = resource->rsrcChildResourcesHead;

    while (tempChildResource)
    {
        if(tempChildResource->rsrcResource == resourceHandle)
        {
            // if resource going to be unbinded is the head one.
            if( tempChildResource == resource->rsrcChildResourcesHead )
            {
                OCChildResource *temp = resource->rsrcChildResourcesHead->next;
                OICFree(resource->rsrcChildResourcesHead);
                resource->rsrcChildResourcesHead = temp;
                temp = NULL;
            }
            else
            {
                OCChildResource *temp = tempChildResource->next;
                OICFree(tempChildResource);
                tempLastChildResource->next = temp;
                temp = NULL;
            }

            OIC_LOG(INFO, TAG, "resource unbound");

            // Send notification when resource is unbounded successfully.
#ifdef WITH_PRESENCE
            if (presenceResource.handle)
            {
                ((OCResource *)presenceResource.handle)->sequenceNum = OCGetRandom();
                SendPresenceNotification(((OCResource *) resourceHandle)->rsrcType,
                        OC_PRESENCE_TRIGGER_CHANGE);
            }
#endif
            tempChildResource = NULL;
            tempLastChildResource = NULL;

            return OC_STACK_OK;

        }

        tempLastChildResource = tempChildResource;
        tempChildResource = tempChildResource->next;
    }

    OIC_LOG(INFO, TAG, "resource not found in collection");

    tempChildResource = NULL;
    tempLastChildResource = NULL;

    // Unable to add resourceHandle, so return error
    return OC_STACK_ERROR;
}

static bool ValidateResourceTypeInterface(const char *resourceItemName)
{
    if (!resourceItemName)
    {
        return false;
    }
    // Per RFC 6690 only registered values must follow the first rule below.
    // At this point in time the only values registered begin with "core", and
    // all other values are specified as opaque strings where multiple values
    // are separated by a space.
    if (strncmp(resourceItemName, CORESPEC, sizeof(CORESPEC) - 1) == 0)
    {
        for(size_t index = sizeof(CORESPEC) - 1;  resourceItemName[index]; ++index)
        {
            if (resourceItemName[index] != '.'
                && resourceItemName[index] != '-'
                && (resourceItemName[index] < 'a' || resourceItemName[index] > 'z')
                && (resourceItemName[index] < '0' || resourceItemName[index] > '9'))
            {
                return false;
            }
        }
    }
    else
    {
        for (size_t index = 0; resourceItemName[index]; ++index)
        {
            if (resourceItemName[index] == ' '
                || resourceItemName[index] == '\t'
                || resourceItemName[index] == '\r'
                || resourceItemName[index] == '\n')
            {
                return false;
            }
        }
    }

    return true;
}

OCStackResult BindResourceTypeToResource(OCResource* resource,
                                            const char *resourceTypeName)
{
    OCResourceType *pointer = NULL;
    char *str = NULL;
    OCStackResult result = OC_STACK_ERROR;

    VERIFY_NON_NULL(resourceTypeName, ERROR, OC_STACK_INVALID_PARAM);

    if (!ValidateResourceTypeInterface(resourceTypeName))
    {
        OIC_LOG(ERROR, TAG, "resource type illegal (see RFC 6690)");
        return OC_STACK_INVALID_PARAM;
    }

    pointer = (OCResourceType *) OICCalloc(1, sizeof(OCResourceType));
    if (!pointer)
    {
        result = OC_STACK_NO_MEMORY;
        goto exit;
    }

    str = OICStrdup(resourceTypeName);
    if (!str)
    {
        result = OC_STACK_NO_MEMORY;
        goto exit;
    }
    pointer->resourcetypename = str;
    pointer->next = NULL;

    insertResourceType(resource, pointer);
    result = OC_STACK_OK;

exit:
    if (result != OC_STACK_OK)
    {
        OICFree(pointer);
        OICFree(str);
    }

    return result;
}

OCStackResult BindResourceInterfaceToResource(OCResource* resource,
        const char *resourceInterfaceName)
{
    OCResourceInterface *pointer = NULL;
    char *str = NULL;
    OCStackResult result = OC_STACK_ERROR;

    VERIFY_NON_NULL(resourceInterfaceName, ERROR, OC_STACK_INVALID_PARAM);

    if (!ValidateResourceTypeInterface(resourceInterfaceName))
    {
        OIC_LOG(ERROR, TAG, "resource /interface illegal (see RFC 6690)");
        return OC_STACK_INVALID_PARAM;
    }

    OIC_LOG_V(INFO, TAG, "Binding %s interface to %s", resourceInterfaceName, resource->uri);

    pointer = (OCResourceInterface *) OICCalloc(1, sizeof(OCResourceInterface));
    if (!pointer)
    {
        result = OC_STACK_NO_MEMORY;
        goto exit;
    }

    str = OICStrdup(resourceInterfaceName);
    if (!str)
    {
        result = OC_STACK_NO_MEMORY;
        goto exit;
    }
    pointer->name = str;

    // Bind the resourceinterface to the resource
    insertResourceInterface(resource, pointer);

    result = OC_STACK_OK;

    exit:
    if (result != OC_STACK_OK)
    {
        OICFree(pointer);
        OICFree(str);
    }

    return result;
}

OCStackResult OCBindResourceTypeToResource(OCResourceHandle handle,
        const char *resourceTypeName)
{

    OCStackResult result = OC_STACK_ERROR;
    OCResource *resource = NULL;

    resource = findResource((OCResource *) handle);
    if (!resource)
    {
        OIC_LOG(ERROR, TAG, "Resource not found");
        return OC_STACK_ERROR;
    }

    result = BindResourceTypeToResource(resource, resourceTypeName);

#ifdef WITH_PRESENCE
    if(presenceResource.handle)
    {
        ((OCResource *)presenceResource.handle)->sequenceNum = OCGetRandom();
        SendPresenceNotification(resource->rsrcType, OC_PRESENCE_TRIGGER_CHANGE);
    }
#endif

    return result;
}

OCStackResult OCBindResourceInterfaceToResource(OCResourceHandle handle,
        const char *resourceInterfaceName)
{

    OCStackResult result = OC_STACK_ERROR;
    OCResource *resource = NULL;

    resource = findResource((OCResource *) handle);
    if (!resource)
    {
        OIC_LOG(ERROR, TAG, "Resource not found");
        return OC_STACK_ERROR;
    }

    result = BindResourceInterfaceToResource(resource, resourceInterfaceName);

#ifdef WITH_PRESENCE
    if (presenceResource.handle)
    {
        ((OCResource *)presenceResource.handle)->sequenceNum = OCGetRandom();
        SendPresenceNotification(resource->rsrcType, OC_PRESENCE_TRIGGER_CHANGE);
    }
#endif

    return result;
}

OCStackResult OCGetNumberOfResources(uint8_t *numResources)
{
    OCResource *pointer = headResource;

    VERIFY_NON_NULL(numResources, ERROR, OC_STACK_INVALID_PARAM);
    *numResources = 0;
    while (pointer)
    {
        *numResources = *numResources + 1;
        pointer = pointer->next;
    }
    return OC_STACK_OK;
}

OCResourceHandle OCGetResourceHandle(uint8_t index)
{
    OCResource *pointer = headResource;

    for( uint8_t i = 0; i < index && pointer; ++i)
    {
        pointer = pointer->next;
    }
    return (OCResourceHandle) pointer;
}

OCStackResult OCDeleteResource(OCResourceHandle handle)
{
    if (!handle)
    {
        OIC_LOG(ERROR, TAG, "Invalid handle for deletion");
        return OC_STACK_INVALID_PARAM;
    }

    OCResource *resource = findResource((OCResource *) handle);
    if (resource == NULL)
    {
        OIC_LOG(ERROR, TAG, "Resource not found");
        return OC_STACK_NO_RESOURCE;
    }

    if (deleteResource((OCResource *) handle) != OC_STACK_OK)
    {
        OIC_LOG(ERROR, TAG, "Error deleting resource");
        return OC_STACK_ERROR;
    }

    return OC_STACK_OK;
}

const char *OCGetResourceUri(OCResourceHandle handle)
{
    OCResource *resource = NULL;

    resource = findResource((OCResource *) handle);
    if (resource)
    {
        return resource->uri;
    }
    return (const char *) NULL;
}

OCResourceProperty OCGetResourceProperties(OCResourceHandle handle)
{
    OCResource *resource = NULL;

    resource = findResource((OCResource *) handle);
    if (resource)
    {
        return resource->resourceProperties;
    }
    return (OCResourceProperty)-1;
}

OCStackResult OCGetNumberOfResourceTypes(OCResourceHandle handle,
        uint8_t *numResourceTypes)
{
    OCResource *resource = NULL;
    OCResourceType *pointer = NULL;

    VERIFY_NON_NULL(numResourceTypes, ERROR, OC_STACK_INVALID_PARAM);
    VERIFY_NON_NULL(handle, ERROR, OC_STACK_INVALID_PARAM);

    *numResourceTypes = 0;

    resource = findResource((OCResource *) handle);
    if (resource)
    {
        pointer = resource->rsrcType;
        while (pointer)
        {
            *numResourceTypes = *numResourceTypes + 1;
            pointer = pointer->next;
        }
    }
    return OC_STACK_OK;
}

const char *OCGetResourceTypeName(OCResourceHandle handle, uint8_t index)
{
    OCResourceType *resourceType = NULL;

    resourceType = findResourceTypeAtIndex(handle, index);
    if (resourceType)
    {
        return resourceType->resourcetypename;
    }
    return (const char *) NULL;
}

OCStackResult OCGetNumberOfResourceInterfaces(OCResourceHandle handle,
        uint8_t *numResourceInterfaces)
{
    OCResourceInterface *pointer = NULL;
    OCResource *resource = NULL;

    VERIFY_NON_NULL(handle, ERROR, OC_STACK_INVALID_PARAM);
    VERIFY_NON_NULL(numResourceInterfaces, ERROR, OC_STACK_INVALID_PARAM);

    *numResourceInterfaces = 0;
    resource = findResource((OCResource *) handle);
    if (resource)
    {
        pointer = resource->rsrcInterface;
        while (pointer)
        {
            *numResourceInterfaces = *numResourceInterfaces + 1;
            pointer = pointer->next;
        }
    }
    return OC_STACK_OK;
}

const char *OCGetResourceInterfaceName(OCResourceHandle handle, uint8_t index)
{
    OCResourceInterface *resourceInterface = NULL;

    resourceInterface = findResourceInterfaceAtIndex(handle, index);
    if (resourceInterface)
    {
        return resourceInterface->name;
    }
    return (const char *) NULL;
}

OCResourceHandle OCGetResourceHandleFromCollection(OCResourceHandle collectionHandle,
        uint8_t index)
{
    OCResource *resource = NULL;
    OCChildResource *tempChildResource = NULL;
    uint8_t num = 0;

    resource = findResource((OCResource *) collectionHandle);
    if (!resource)
    {
        return NULL;
    }

    tempChildResource = resource->rsrcChildResourcesHead;

    while(tempChildResource)
    {
        if( num == index )
        {
            return tempChildResource->rsrcResource;
        }
        num++;
        tempChildResource = tempChildResource->next;
    }

    // In this case, the number of resource handles in the collection exceeds the index
    tempChildResource = NULL;
    return NULL;
}

OCStackResult OCBindResourceHandler(OCResourceHandle handle,
        OCEntityHandler entityHandler,
        void* callbackParam)
{
    OCResource *resource = NULL;

    // Validate parameters
    VERIFY_NON_NULL(handle, ERROR, OC_STACK_INVALID_PARAM);

    // Use the handle to find the resource in the resource linked list
    resource = findResource((OCResource *)handle);
    if (!resource)
    {
        OIC_LOG(ERROR, TAG, "Resource not found");
        return OC_STACK_ERROR;
    }

    // Bind the handler
    resource->entityHandler = entityHandler;
    resource->entityHandlerCallbackParam = callbackParam;

#ifdef WITH_PRESENCE
    if (presenceResource.handle)
    {
        ((OCResource *)presenceResource.handle)->sequenceNum = OCGetRandom();
        SendPresenceNotification(resource->rsrcType, OC_PRESENCE_TRIGGER_CHANGE);
    }
#endif

    return OC_STACK_OK;
}

OCEntityHandler OCGetResourceHandler(OCResourceHandle handle)
{
    OCResource *resource = NULL;

    resource = findResource((OCResource *)handle);
    if (!resource)
    {
        OIC_LOG(ERROR, TAG, "Resource not found");
        return NULL;
    }

    // Bind the handler
    return resource->entityHandler;
}

void incrementSequenceNumber(OCResource * resPtr)
{
    // Increment the sequence number
    resPtr->sequenceNum += 1;
    if (resPtr->sequenceNum == MAX_SEQUENCE_NUMBER)
    {
        resPtr->sequenceNum = OC_OFFSET_SEQUENCE_NUMBER+1;
    }
    return;
}

#ifdef WITH_PRESENCE
OCStackResult SendPresenceNotification(OCResourceType *resourceType,
        OCPresenceTrigger trigger)
{
    OCResource *resPtr = NULL;
    OCStackResult result = OC_STACK_ERROR;
    OCMethod method = OC_REST_PRESENCE;
    uint32_t maxAge = 0;
    resPtr = findResource((OCResource *) presenceResource.handle);
    if(NULL == resPtr)
    {
        return OC_STACK_NO_RESOURCE;
    }

    if((((OCResource *) presenceResource.handle)->resourceProperties) & OC_ACTIVE)
    {
        maxAge = presenceResource.presenceTTL;

        result = SendAllObserverNotification(method, resPtr, maxAge,
                trigger, resourceType, OC_LOW_QOS);
    }

    return result;
}

OCStackResult SendStopNotification()
{
    OCResource *resPtr = NULL;
    OCStackResult result = OC_STACK_ERROR;
    OCMethod method = OC_REST_PRESENCE;
    resPtr = findResource((OCResource *) presenceResource.handle);
    if(NULL == resPtr)
    {
        return OC_STACK_NO_RESOURCE;
    }

    // maxAge is 0. ResourceType is NULL.
    result = SendAllObserverNotification(method, resPtr, 0, OC_PRESENCE_TRIGGER_DELETE,
            NULL, OC_LOW_QOS);

    return result;
}

#endif // WITH_PRESENCE
OCStackResult OCNotifyAllObservers(OCResourceHandle handle, OCQualityOfService qos)
{
    OCResource *resPtr = NULL;
    OCStackResult result = OC_STACK_ERROR;
    OCMethod method = OC_REST_NOMETHOD;
    uint32_t maxAge = 0;

    OIC_LOG(INFO, TAG, "Notifying all observers");
#ifdef WITH_PRESENCE
    if(handle == presenceResource.handle)
    {
        return OC_STACK_OK;
    }
#endif // WITH_PRESENCE
    VERIFY_NON_NULL(handle, ERROR, OC_STACK_ERROR);

    // Verify that the resource exists
    resPtr = findResource ((OCResource *) handle);
    if (NULL == resPtr)
    {
        return OC_STACK_NO_RESOURCE;
    }
    else
    {
        //only increment in the case of regular observing (not presence)
        incrementSequenceNumber(resPtr);
        method = OC_REST_OBSERVE;
        maxAge = MAX_OBSERVE_AGE;
#ifdef WITH_PRESENCE
        result = SendAllObserverNotification (method, resPtr, maxAge,
                OC_PRESENCE_TRIGGER_DELETE, NULL, qos);
#else
        result = SendAllObserverNotification (method, resPtr, maxAge, qos);
#endif
        return result;
    }
}

OCStackResult
OCNotifyListOfObservers (OCResourceHandle handle,
                         OCObservationId  *obsIdList,
                         uint8_t          numberOfIds,
                         const OCRepPayload       *payload,
                         OCQualityOfService qos)
{
    OIC_LOG(INFO, TAG, "Entering OCNotifyListOfObservers");

    OCResource *resPtr = NULL;
    //TODO: we should allow the server to define this
    uint32_t maxAge = MAX_OBSERVE_AGE;

    VERIFY_NON_NULL(handle, ERROR, OC_STACK_ERROR);
    VERIFY_NON_NULL(obsIdList, ERROR, OC_STACK_ERROR);
    VERIFY_NON_NULL(payload, ERROR, OC_STACK_ERROR);

    resPtr = findResource ((OCResource *) handle);
    if (NULL == resPtr || myStackMode == OC_CLIENT)
    {
        return OC_STACK_NO_RESOURCE;
    }
    else
    {
        incrementSequenceNumber(resPtr);
    }
    return (SendListObserverNotification(resPtr, obsIdList, numberOfIds,
            payload, maxAge, qos));
}

OCStackResult OCDoResponse(OCEntityHandlerResponse *ehResponse)
{
    OCStackResult result = OC_STACK_ERROR;
    OCServerRequest *serverRequest = NULL;

    OIC_LOG(INFO, TAG, "Entering OCDoResponse");

    // Validate input parameters
    VERIFY_NON_NULL(ehResponse, ERROR, OC_STACK_INVALID_PARAM);
    VERIFY_NON_NULL(ehResponse->requestHandle, ERROR, OC_STACK_INVALID_PARAM);

    // Normal response
    // Get pointer to request info
    serverRequest = GetServerRequestUsingHandle((OCServerRequest *)ehResponse->requestHandle);
    if(serverRequest)
    {
        // response handler in ocserverrequest.c. Usually HandleSingleResponse.
        result = serverRequest->ehResponseHandler(ehResponse);
    }

    return result;
}

//#ifdef DIRECT_PAIRING
const OCDPDev_t* OCDiscoverDirectPairingDevices(unsigned short waittime)
{
    OIC_LOG(INFO, TAG, "Start OCDiscoverDirectPairingDevices");
    if(OC_STACK_OK != DPDeviceDiscovery(waittime))
    {
        OIC_LOG(ERROR, TAG, "Fail to discover Direct-Pairing device");
        return NULL;
    }

    return (const OCDPDev_t*)DPGetDiscoveredDevices();
}

const OCDPDev_t* OCGetDirectPairedDevices()
{
    return (const OCDPDev_t*)DPGetPairedDevices();
}

OCStackResult OCDoDirectPairing(void *ctx, OCDPDev_t* peer, OCPrm_t pmSel, char *pinNumber,
                                                     OCDirectPairingCB resultCallback)
{
    OIC_LOG(INFO, TAG, "Start OCDoDirectPairing");
    if(NULL ==  peer || NULL == pinNumber)
    {
        OIC_LOG(ERROR, TAG, "Invalid parameters");
        return OC_STACK_INVALID_PARAM;
    }
    if (NULL == resultCallback)
    {
        OIC_LOG(ERROR, TAG, "Invalid callback");
        return OC_STACK_INVALID_CALLBACK;
    }

    return DPDirectPairing(ctx, (OCDirectPairingDev_t*)peer, (OicSecPrm_t)pmSel,
                                           pinNumber, (OCDirectPairingResultCB)resultCallback);
}
//#endif // DIRECT_PAIRING

//-----------------------------------------------------------------------------
// Private internal function definitions
//-----------------------------------------------------------------------------
static OCDoHandle GenerateInvocationHandle()
{
    OCDoHandle handle = NULL;
    // Generate token here, it will be deleted when the transaction is deleted
    handle = (OCDoHandle) OICMalloc(sizeof(uint8_t[CA_MAX_TOKEN_LEN]));
    if (handle)
    {
        OCFillRandomMem((uint8_t*)handle, sizeof(uint8_t[CA_MAX_TOKEN_LEN]));
    }

    return handle;
}

#ifdef WITH_PRESENCE
OCStackResult OCChangeResourceProperty(OCResourceProperty * inputProperty,
        OCResourceProperty resourceProperties, uint8_t enable)
{
    if (!inputProperty)
    {
        return OC_STACK_INVALID_PARAM;
    }
    if (resourceProperties
            > (OC_ACTIVE | OC_DISCOVERABLE | OC_OBSERVABLE | OC_SLOW))
    {
        OIC_LOG(ERROR, TAG, "Invalid property");
        return OC_STACK_INVALID_PARAM;
    }
    if(!enable)
    {
        *inputProperty = (OCResourceProperty) (*inputProperty & ~(resourceProperties));
    }
    else
    {
        *inputProperty = (OCResourceProperty) (*inputProperty | resourceProperties);
    }
    return OC_STACK_OK;
}
#endif

OCStackResult initResources()
{
    OCStackResult result = OC_STACK_OK;

    headResource = NULL;
    tailResource = NULL;
    // Init Virtual Resources
#ifdef WITH_PRESENCE
    presenceResource.presenceTTL = OC_DEFAULT_PRESENCE_TTL_SECONDS;

    result = OCCreateResource(&presenceResource.handle,
            OC_RSRVD_RESOURCE_TYPE_PRESENCE,
            "core.r",
            OC_RSRVD_PRESENCE_URI,
            NULL,
            NULL,
            OC_OBSERVABLE);
    //make resource inactive
    result = OCChangeResourceProperty(
            &(((OCResource *) presenceResource.handle)->resourceProperties),
            OC_ACTIVE, 0);
#endif
#ifndef WITH_ARDUINO
    if (result == OC_STACK_OK)
    {
        result = SRMInitSecureResources();
    }
#endif

    if(result == OC_STACK_OK)
    {
        CreateResetProfile();
        result = OCCreateResource(&deviceResource,
                                  OC_RSRVD_RESOURCE_TYPE_DEVICE,
                                  OC_RSRVD_INTERFACE_DEFAULT,
                                  OC_RSRVD_DEVICE_URI,
                                  NULL,
                                  NULL,
                                  OC_DISCOVERABLE);
        if(result == OC_STACK_OK)
        {
            result = BindResourceInterfaceToResource((OCResource *)deviceResource,
                                                     OC_RSRVD_INTERFACE_READ);
        }
    }

    if(result == OC_STACK_OK)
    {
        result = OCCreateResource(&platformResource,
                                  OC_RSRVD_RESOURCE_TYPE_PLATFORM,
                                  OC_RSRVD_INTERFACE_DEFAULT,
                                  OC_RSRVD_PLATFORM_URI,
                                  NULL,
                                  NULL,
                                  OC_DISCOVERABLE);
        if(result == OC_STACK_OK)
        {
            result = BindResourceInterfaceToResource((OCResource *)platformResource,
                                                     OC_RSRVD_INTERFACE_READ);
        }
    }

    return result;
}

void insertResource(OCResource *resource)
{
    if (!headResource)
    {
        headResource = resource;
        tailResource = resource;
    }
    else
    {
        tailResource->next = resource;
        tailResource = resource;
    }
    resource->next = NULL;
}

OCResource *findResource(OCResource *resource)
{
    OCResource *pointer = headResource;

    while (pointer)
    {
        if (pointer == resource)
        {
            return resource;
        }
        pointer = pointer->next;
    }
    return NULL;
}

void deleteAllResources()
{
    OCResource *pointer = headResource;
    OCResource *temp = NULL;

    while (pointer)
    {
        temp = pointer->next;
#ifdef WITH_PRESENCE
        if (pointer != (OCResource *) presenceResource.handle)
        {
#endif // WITH_PRESENCE
            deleteResource(pointer);
#ifdef WITH_PRESENCE
        }
#endif // WITH_PRESENCE
        pointer = temp;
    }
    memset(&platformResource, 0, sizeof(platformResource));
    memset(&deviceResource, 0, sizeof(deviceResource));
#ifdef MQ_BROKER
    memset(&brokerResource, 0, sizeof(brokerResource));
#endif

    SRMDeInitSecureResources();

#ifdef WITH_PRESENCE
    // Ensure that the last resource to be deleted is the presence resource. This allows for all
    // presence notification attributed to their deletion to be processed.
    deleteResource((OCResource *) presenceResource.handle);
    memset(&presenceResource, 0, sizeof(presenceResource));
#endif // WITH_PRESENCE
}

OCStackResult deleteResource(OCResource *resource)
{
    OCResource *prev = NULL;
    OCResource *temp = NULL;
    if(!resource)
    {
        OIC_LOG(DEBUG,TAG,"resource is NULL");
        return OC_STACK_INVALID_PARAM;
    }

    OIC_LOG_V (INFO, TAG, "Deleting resource %s", resource->uri);

    temp = headResource;
    while (temp)
    {
        if (temp == resource)
        {
            // Invalidate all Resource Properties.
            resource->resourceProperties = (OCResourceProperty) 0;
#ifdef WITH_PRESENCE
            if(resource != (OCResource *) presenceResource.handle)
            {
#endif // WITH_PRESENCE
                OCNotifyAllObservers((OCResourceHandle)resource, OC_HIGH_QOS);
#ifdef WITH_PRESENCE
            }

            if(presenceResource.handle)
            {
                ((OCResource *)presenceResource.handle)->sequenceNum = OCGetRandom();
                SendPresenceNotification(resource->rsrcType, OC_PRESENCE_TRIGGER_DELETE);
            }
#endif
            // Only resource in list.
            if (temp == headResource && temp == tailResource)
            {
                headResource = NULL;
                tailResource = NULL;
            }
            // Deleting head.
            else if (temp == headResource)
            {
                headResource = temp->next;
            }
            // Deleting tail.
            else if (temp == tailResource)
            {
                tailResource = prev;
                tailResource->next = NULL;
            }
            else
            {
                prev->next = temp->next;
            }

            deleteResourceElements(temp);
            OICFree(temp);
            return OC_STACK_OK;
        }
        else
        {
            prev = temp;
            temp = temp->next;
        }
    }

    return OC_STACK_ERROR;
}

void deleteResourceElements(OCResource *resource)
{
    if (!resource)
    {
        return;
    }

    OICFree(resource->uri);
    deleteResourceType(resource->rsrcType);
    deleteResourceInterface(resource->rsrcInterface);
}

void deleteResourceType(OCResourceType *resourceType)
{
    OCResourceType *pointer = resourceType;
    OCResourceType *next = NULL;

    while (pointer)
    {
        next = pointer->next;
        OICFree(pointer->resourcetypename);
        OICFree(pointer);
        pointer = next;
    }
}

void deleteResourceInterface(OCResourceInterface *resourceInterface)
{
    OCResourceInterface *pointer = resourceInterface;
    OCResourceInterface *next = NULL;

    while (pointer)
    {
        next = pointer->next;
        OICFree(pointer->name);
        OICFree(pointer);
        pointer = next;
    }
}

void insertResourceType(OCResource *resource, OCResourceType *resourceType)
{
    OCResourceType *pointer = NULL;
    OCResourceType *previous = NULL;
    if (!resource || !resourceType)
    {
        return;
    }
    // resource type list is empty.
    else if (!resource->rsrcType)
    {
        resource->rsrcType = resourceType;
    }
    else
    {
        pointer = resource->rsrcType;

        while (pointer)
        {
            if (!strcmp(resourceType->resourcetypename, pointer->resourcetypename))
            {
                OIC_LOG_V(INFO, TAG, "Type %s already exists", resourceType->resourcetypename);
                OICFree(resourceType->resourcetypename);
                OICFree(resourceType);
                return;
            }
            previous = pointer;
            pointer = pointer->next;
        }

        if (previous)
        {
            previous->next = resourceType;
        }
    }
    resourceType->next = NULL;

    OIC_LOG_V(INFO, TAG, "Added type %s to %s", resourceType->resourcetypename, resource->uri);
}

OCResourceType *findResourceTypeAtIndex(OCResourceHandle handle, uint8_t index)
{
    OCResource *resource = NULL;
    OCResourceType *pointer = NULL;

    // Find the specified resource
    resource = findResource((OCResource *) handle);
    if (!resource)
    {
        return NULL;
    }

    // Make sure a resource has a resourcetype
    if (!resource->rsrcType)
    {
        return NULL;
    }

    // Iterate through the list
    pointer = resource->rsrcType;
    for(uint8_t i = 0; i< index && pointer; ++i)
    {
        pointer = pointer->next;
    }
    return pointer;
}

OCResourceType *findResourceType(OCResourceType * resourceTypeList, const char * resourceTypeName)
{
    if(resourceTypeList && resourceTypeName)
    {
        OCResourceType * rtPointer = resourceTypeList;
        while(resourceTypeName && rtPointer)
        {
            if(rtPointer->resourcetypename &&
                    strcmp(resourceTypeName, (const char *)
                    (rtPointer->resourcetypename)) == 0)
            {
                break;
            }
            rtPointer = rtPointer->next;
        }
        return rtPointer;
    }
    return NULL;
}

/*
 * Insert a new interface into interface linked list only if not already present.
 * If alredy present, 2nd arg is free'd.
 * Default interface will always be first if present.
 */
void insertResourceInterface(OCResource *resource, OCResourceInterface *newInterface)
{
    OCResourceInterface *pointer = NULL;
    OCResourceInterface *previous = NULL;

    newInterface->next = NULL;

    OCResourceInterface **firstInterface = &(resource->rsrcInterface);

    if (!*firstInterface)
    {
        // If first interface is not oic.if.baseline, by default add it as first interface type.
        if (0 == strcmp(newInterface->name, OC_RSRVD_INTERFACE_DEFAULT))
        {
            *firstInterface = newInterface;
        }
        else
        {
            OCStackResult result = BindResourceInterfaceToResource(resource,
                                                                    OC_RSRVD_INTERFACE_DEFAULT);
            if (result != OC_STACK_OK)
            {
                OICFree(newInterface->name);
                OICFree(newInterface);
                return;
            }
            if (*firstInterface)
            {
                (*firstInterface)->next = newInterface;
            }
        }
    }
    // If once add oic.if.baseline, later too below code take care of freeing memory.
    else if (strcmp(newInterface->name, OC_RSRVD_INTERFACE_DEFAULT) == 0)
    {
        if (strcmp((*firstInterface)->name, OC_RSRVD_INTERFACE_DEFAULT) == 0)
        {
            OICFree(newInterface->name);
            OICFree(newInterface);
            return;
        }
        // This code will not hit anymore, keeping
        else
        {
            newInterface->next = *firstInterface;
            *firstInterface = newInterface;
        }
    }
    else
    {
        pointer = *firstInterface;
        while (pointer)
        {
            if (strcmp(newInterface->name, pointer->name) == 0)
            {
                OICFree(newInterface->name);
                OICFree(newInterface);
                return;
            }
            previous = pointer;
            pointer = pointer->next;
        }

        if (previous)
        {
            previous->next = newInterface;
        }
    }
}

OCResourceInterface *findResourceInterfaceAtIndex(OCResourceHandle handle,
        uint8_t index)
{
    OCResource *resource = NULL;
    OCResourceInterface *pointer = NULL;

    // Find the specified resource
    resource = findResource((OCResource *) handle);
    if (!resource)
    {
        return NULL;
    }

    // Make sure a resource has a resourceinterface
    if (!resource->rsrcInterface)
    {
        return NULL;
    }

    // Iterate through the list
    pointer = resource->rsrcInterface;

    for (uint8_t i = 0; i < index && pointer; ++i)
    {
        pointer = pointer->next;
    }
    return pointer;
}

/*
 * This function splits the uri using the '?' delimiter.
 * "uriWithoutQuery" is the block of characters between the beginning
 * till the delimiter or '\0' which ever comes first.
 * "query" is whatever is to the right of the delimiter if present.
 * No delimiter sets the query to NULL.
 * If either are present, they will be malloc'ed into the params 2, 3.
 * The first param, *uri is left untouched.

 * NOTE: This function does not account for whitespace at the end of the uri NOR
 *       malformed uri's with '??'. Whitespace at the end will be assumed to be
 *       part of the query.
 */
OCStackResult getQueryFromUri(const char * uri, char** query, char ** uriWithoutQuery)
{
    if(!uri)
    {
        return OC_STACK_INVALID_URI;
    }
    if(!query || !uriWithoutQuery)
    {
        return OC_STACK_INVALID_PARAM;
    }

    *query           = NULL;
    *uriWithoutQuery = NULL;

    size_t uriWithoutQueryLen = 0;
    size_t queryLen = 0;
    size_t uriLen = strlen(uri);

    char *pointerToDelimiter = strstr(uri, "?");

    uriWithoutQueryLen = pointerToDelimiter == NULL ? uriLen : (size_t)(pointerToDelimiter - uri);
    queryLen = pointerToDelimiter == NULL ? 0 : uriLen - uriWithoutQueryLen - 1;

    if (uriWithoutQueryLen)
    {
        *uriWithoutQuery =  (char *) OICCalloc(uriWithoutQueryLen + 1, 1);
        if (!*uriWithoutQuery)
        {
            goto exit;
        }
        OICStrcpy(*uriWithoutQuery, uriWithoutQueryLen +1, uri);
    }
    if (queryLen)
    {
        *query = (char *) OICCalloc(queryLen + 1, 1);
        if (!*query)
        {
            OICFree(*uriWithoutQuery);
            *uriWithoutQuery = NULL;
            goto exit;
        }
        OICStrcpy(*query, queryLen + 1, pointerToDelimiter + 1);
    }

    return OC_STACK_OK;

    exit:
        return OC_STACK_NO_MEMORY;
}

static const OicUuid_t* OCGetServerInstanceID(void)
{
    static bool generated = false;
    static OicUuid_t sid;
    if (generated)
    {
        return &sid;
    }

    if (OC_STACK_OK != GetDoxmDeviceID(&sid))
    {
        OIC_LOG(FATAL, TAG, "Generate UUID for Server Instance failed!");
        return NULL;
    }
    generated = true;
    return &sid;
}

const char* OCGetServerInstanceIDString(void)
{
    static bool generated = false;
    static char sidStr[UUID_STRING_SIZE];

    if(generated)
    {
        return sidStr;
    }

    const OicUuid_t *sid = OCGetServerInstanceID();
    if(OCConvertUuidToString(sid->id, sidStr) != RAND_UUID_OK)
    {
        OIC_LOG(FATAL, TAG, "Generate UUID String for Server Instance failed!");
        return NULL;
    }

    generated = true;
    return sidStr;
}

CAResult_t OCSelectNetwork()
{
    CAResult_t retResult = CA_STATUS_FAILED;
    CAResult_t caResult = CA_STATUS_OK;

    CATransportAdapter_t connTypes[] = {
            CA_ADAPTER_IP,
            CA_ADAPTER_RFCOMM_BTEDR,
            CA_ADAPTER_GATT_BTLE,
            CA_ADAPTER_NFC
#ifdef RA_ADAPTER
            ,CA_ADAPTER_REMOTE_ACCESS
#endif

#ifdef TCP_ADAPTER
            ,CA_ADAPTER_TCP
#endif
        };
    int numConnTypes = sizeof(connTypes)/sizeof(connTypes[0]);

    for(int i = 0; i<numConnTypes; i++)
    {
        // Ignore CA_NOT_SUPPORTED error. The CA Layer may have not compiled in the interface.
        if(caResult == CA_STATUS_OK || caResult == CA_NOT_SUPPORTED)
        {
           caResult = CASelectNetwork(connTypes[i]);
           if(caResult == CA_STATUS_OK)
           {
               retResult = CA_STATUS_OK;
           }
        }
    }

    if(retResult != CA_STATUS_OK)
    {
        return caResult; // Returns error of appropriate transport that failed fatally.
    }

    return retResult;
}

OCStackResult CAResultToOCResult(CAResult_t caResult)
{
    switch (caResult)
    {
        case CA_STATUS_OK:
            return OC_STACK_OK;
        case CA_STATUS_INVALID_PARAM:
            return OC_STACK_INVALID_PARAM;
        case CA_ADAPTER_NOT_ENABLED:
            return OC_STACK_ADAPTER_NOT_ENABLED;
        case CA_SERVER_STARTED_ALREADY:
            return OC_STACK_OK;
        case CA_SERVER_NOT_STARTED:
            return OC_STACK_ERROR;
        case CA_DESTINATION_NOT_REACHABLE:
            return OC_STACK_COMM_ERROR;
        case CA_SOCKET_OPERATION_FAILED:
            return OC_STACK_COMM_ERROR;
        case CA_SEND_FAILED:
            return OC_STACK_COMM_ERROR;
        case CA_RECEIVE_FAILED:
            return OC_STACK_COMM_ERROR;
        case CA_MEMORY_ALLOC_FAILED:
            return OC_STACK_NO_MEMORY;
        case CA_REQUEST_TIMEOUT:
            return OC_STACK_TIMEOUT;
        case CA_DESTINATION_DISCONNECTED:
            return OC_STACK_COMM_ERROR;
        case CA_STATUS_FAILED:
            return OC_STACK_ERROR;
        case CA_NOT_SUPPORTED:
            return OC_STACK_NOTIMPL;
        default:
            return OC_STACK_ERROR;
    }
}

bool OCResultToSuccess(OCStackResult ocResult)
{
    switch (ocResult)
    {
        case OC_STACK_OK:
        case OC_STACK_RESOURCE_CREATED:
        case OC_STACK_RESOURCE_DELETED:
        case OC_STACK_CONTINUE:
        case OC_STACK_RESOURCE_CHANGED:
            return true;
        default:
            return false;
    }
}

#if defined(RD_CLIENT) || defined(RD_SERVER)
OCStackResult OCBindResourceInsToResource(OCResourceHandle handle, uint8_t ins)
{
    VERIFY_NON_NULL(handle, ERROR, OC_STACK_INVALID_PARAM);

    OCResource *resource = NULL;

    resource = findResource((OCResource *) handle);
    if (!resource)
    {
        OIC_LOG(ERROR, TAG, "Resource not found");
        return OC_STACK_ERROR;
    }

    resource->ins = ins;

    return OC_STACK_OK;
}

OCResourceHandle OCGetResourceHandleAtUri(const char *uri)
{
    if (!uri)
    {
        OIC_LOG(ERROR, TAG, "Resource uri is NULL");
        return NULL;
    }

    OCResource *pointer = headResource;

    while (pointer)
    {
        if (strncmp(uri, pointer->uri, MAX_URI_LENGTH) == 0)
        {
            OIC_LOG_V(DEBUG, TAG, "Found Resource %s", uri);
            return pointer;
        }
        pointer = pointer->next;
    }
    return NULL;
}

OCStackResult OCGetResourceIns(OCResourceHandle handle, uint8_t *ins)
{
    OCResource *resource = NULL;

    VERIFY_NON_NULL(handle, ERROR, OC_STACK_INVALID_PARAM);
    VERIFY_NON_NULL(ins, ERROR, OC_STACK_INVALID_PARAM);

    resource = findResource((OCResource *) handle);
    if (resource)
    {
        *ins = resource->ins;
        return OC_STACK_OK;
    }
    return OC_STACK_ERROR;
}
#endif