chpp/services/wwan.c

/*
 * Copyright (C) 2020 The Android Open Source Project
 *
 * 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.
 */

#include "chpp/services/wwan.h"

#include <inttypes.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

#include "chpp/common/standard_uuids.h"
#include "chpp/common/wwan.h"
#include "chpp/common/wwan_types.h"
#include "chpp/log.h"
#include "chpp/macros.h"
#include "chpp/memory.h"
#include "chpp/services.h"
#include "chre/pal/wwan.h"

/************************************************
 *  Prototypes
 ***********************************************/

static enum ChppAppErrorCode chppDispatchWwanRequest(void *serviceContext,
                                                     uint8_t *buf, size_t len);
static void chppWwanServiceNotifyReset(void *serviceContext);

/************************************************
 *  Private Definitions
 ***********************************************/

/**
 * Configuration parameters for this service
 */
static const struct ChppService kWwanServiceConfig = {
    .descriptor.uuid = CHPP_UUID_WWAN_STANDARD,

    // Human-readable name
    .descriptor.name = "WWAN",

    // Version
    .descriptor.version.major = 1,
    .descriptor.version.minor = 0,
    .descriptor.version.patch = 0,

    // Notifies service if CHPP is reset
    .resetNotifierFunctionPtr = &chppWwanServiceNotifyReset,

    // Client request dispatch function pointer
    .requestDispatchFunctionPtr = &chppDispatchWwanRequest,

    // Client notification dispatch function pointer
    .notificationDispatchFunctionPtr = NULL,  // Not supported

    // Min length is the entire header
    .minLength = sizeof(struct ChppAppHeader),
};

/**
 * Structure to maintain state for the WWAN service and its Request/Response
 * (RR) functionality.
 */
struct ChppWwanServiceState {
  struct ChppEndpointState service;  // CHPP service state
  const struct chrePalWwanApi *api;  // WWAN PAL API

  struct ChppIncomingRequestState open;              // Service init state
  struct ChppIncomingRequestState close;             // Service deinit state
  struct ChppIncomingRequestState getCapabilities;   // Get Capabilities state
  struct ChppIncomingRequestState getCellInfoAsync;  // Get CellInfo Async state
};

// Note: This global definition of gWwanServiceContext supports only one
// instance of the CHPP WWAN service at a time. This limitation is primarily due
// to the PAL API.
// It would be possible to generate different API and callback pointers to
// support multiple instances of the service or modify the PAL API to pass a
// void* for context, but this is not necessary in the current version of CHPP.
// In such case, wwanServiceContext would be allocated dynamically as part of
// chppRegisterWwanService(), e.g.
//   struct ChppWwanServiceState *wwanServiceContext = chppMalloc(...);
// instead of globally here.
struct ChppWwanServiceState gWwanServiceContext;

/************************************************
 *  Prototypes
 ***********************************************/

static enum ChppAppErrorCode chppWwanServiceOpen(
    struct ChppWwanServiceState *wwanServiceContext,
    struct ChppAppHeader *requestHeader);
static enum ChppAppErrorCode chppWwanServiceClose(
    struct ChppWwanServiceState *wwanServiceContext,
    struct ChppAppHeader *requestHeader);
static enum ChppAppErrorCode chppWwanServiceGetCapabilities(
    struct ChppWwanServiceState *wwanServiceContext,
    struct ChppAppHeader *requestHeader);
static enum ChppAppErrorCode chppWwanServiceGetCellInfoAsync(
    struct ChppWwanServiceState *wwanServiceContext,
    struct ChppAppHeader *requestHeader);

static void chppWwanServiceCellInfoResultCallback(
    struct chreWwanCellInfoResult *result);

/************************************************
 *  Private Functions
 ***********************************************/

/**
 * Dispatches a client request from the transport layer that is determined to be
 * for the WWAN service. If the result of the dispatch is an error, this
 * function responds to the client with the same error.
 *
 * This function is called from the app layer using its function pointer given
 * during service registration.
 *
 * @param serviceContext Maintains status for each service instance.
 * @param buf Input data. Cannot be null.
 * @param len Length of input data in bytes.
 *
 * @return Indicates the result of this function call.
 */
static enum ChppAppErrorCode chppDispatchWwanRequest(void *serviceContext,
                                                     uint8_t *buf, size_t len) {
  struct ChppAppHeader *rxHeader = (struct ChppAppHeader *)buf;
  struct ChppWwanServiceState *wwanServiceContext =
      (struct ChppWwanServiceState *)serviceContext;
  struct ChppIncomingRequestState *inReqState = NULL;
  enum ChppAppErrorCode error = CHPP_APP_ERROR_NONE;
  bool dispatched = true;

  UNUSED_VAR(len);

  switch (rxHeader->command) {
    case CHPP_WWAN_OPEN: {
      inReqState = &wwanServiceContext->open;
      chppTimestampIncomingRequest(inReqState, rxHeader);
      error = chppWwanServiceOpen(wwanServiceContext, rxHeader);
      break;
    }

    case CHPP_WWAN_CLOSE: {
      inReqState = &wwanServiceContext->close;
      chppTimestampIncomingRequest(inReqState, rxHeader);
      error = chppWwanServiceClose(wwanServiceContext, rxHeader);
      break;
    }

    case CHPP_WWAN_GET_CAPABILITIES: {
      inReqState = &wwanServiceContext->getCapabilities;
      chppTimestampIncomingRequest(inReqState, rxHeader);
      error = chppWwanServiceGetCapabilities(wwanServiceContext, rxHeader);
      break;
    }

    case CHPP_WWAN_GET_CELLINFO_ASYNC: {
      inReqState = &wwanServiceContext->getCellInfoAsync;
      chppTimestampIncomingRequest(inReqState, rxHeader);
      error = chppWwanServiceGetCellInfoAsync(wwanServiceContext, rxHeader);
      break;
    }

    default: {
      dispatched = false;
      error = CHPP_APP_ERROR_INVALID_COMMAND;
      break;
    }
  }

  if (dispatched == true && error != CHPP_APP_ERROR_NONE) {
    // Request was dispatched but an error was returned. Close out
    // chppTimestampIncomingRequest()
    chppTimestampOutgoingResponse(inReqState);
  }

  return error;
}

/**
 * Initializes the WWAN service upon an open request from the client and
 * responds to the client with the result.
 *
 * @param serviceContext Maintains status for each service instance.
 * @param requestHeader App layer header of the request.
 *
 * @return Indicates the result of this function call.
 */
static enum ChppAppErrorCode chppWwanServiceOpen(
    struct ChppWwanServiceState *wwanServiceContext,
    struct ChppAppHeader *requestHeader) {
  static const struct chrePalWwanCallbacks palCallbacks = {
      .cellInfoResultCallback = chppWwanServiceCellInfoResultCallback,
  };

  enum ChppAppErrorCode error = CHPP_APP_ERROR_NONE;

  if (wwanServiceContext->service.openState == CHPP_OPEN_STATE_OPENED) {
    CHPP_DEBUG_ASSERT_LOG(false, "WWAN service already open");
    error = CHPP_APP_ERROR_INVALID_COMMAND;

  } else if (!wwanServiceContext->api->open(
                 wwanServiceContext->service.appContext->systemApi,
                 &palCallbacks)) {
    CHPP_DEBUG_ASSERT_LOG(false, "WWAN PAL open failed");
    error = CHPP_APP_ERROR_BEYOND_CHPP;

  } else {
    CHPP_LOGD("WWAN service opened");
    wwanServiceContext->service.openState = CHPP_OPEN_STATE_OPENED;

    struct ChppAppHeader *response =
        chppAllocResponseFixed(requestHeader, struct ChppAppHeader);
    size_t responseLen = sizeof(*response);

    if (response == NULL) {
      CHPP_LOG_OOM();
      error = CHPP_APP_ERROR_OOM;
    } else {
      chppSendTimestampedResponseOrFail(wwanServiceContext->service.appContext,
                                        &wwanServiceContext->open, response,
                                        responseLen);
    }
  }

  return error;
}

/**
 * Deinitializes the WWAN service.
 *
 * @param serviceContext Maintains status for each service instance.
 * @param requestHeader App layer header of the request.
 *
 * @return Indicates the result of this function call.
 */
static enum ChppAppErrorCode chppWwanServiceClose(
    struct ChppWwanServiceState *wwanServiceContext,
    struct ChppAppHeader *requestHeader) {
  enum ChppAppErrorCode error = CHPP_APP_ERROR_NONE;

  wwanServiceContext->api->close();
  wwanServiceContext->service.openState = CHPP_OPEN_STATE_CLOSED;

  CHPP_LOGD("WWAN service closed");

  struct ChppAppHeader *response =
      chppAllocResponseFixed(requestHeader, struct ChppAppHeader);
  size_t responseLen = sizeof(*response);

  if (response == NULL) {
    CHPP_LOG_OOM();
    error = CHPP_APP_ERROR_OOM;
  } else {
    chppSendTimestampedResponseOrFail(wwanServiceContext->service.appContext,
                                      &wwanServiceContext->close, response,
                                      responseLen);
  }

  return error;
}

/**
 * Notifies the service of an incoming reset.
 *
 * @param serviceContext Maintains status for each service instance.
 */
static void chppWwanServiceNotifyReset(void *serviceContext) {
  struct ChppWwanServiceState *wwanServiceContext =
      (struct ChppWwanServiceState *)serviceContext;

  if (wwanServiceContext->service.openState != CHPP_OPEN_STATE_OPENED) {
    CHPP_LOGW("WWAN service reset but wasn't open");
  } else {
    CHPP_LOGD("WWAN service reset. Closing");
    wwanServiceContext->service.openState = CHPP_OPEN_STATE_CLOSED;
    wwanServiceContext->api->close();
  }
}

/**
 * Retrieves a set of flags indicating the WWAN features supported by the
 * current implementation.
 *
 * @param serviceContext Maintains status for each service instance.
 * @param requestHeader App layer header of the request.
 *
 * @return Indicates the result of this function call.
 */
static enum ChppAppErrorCode chppWwanServiceGetCapabilities(
    struct ChppWwanServiceState *wwanServiceContext,
    struct ChppAppHeader *requestHeader) {
  enum ChppAppErrorCode error = CHPP_APP_ERROR_NONE;

  struct ChppWwanGetCapabilitiesResponse *response = chppAllocResponseFixed(
      requestHeader, struct ChppWwanGetCapabilitiesResponse);
  size_t responseLen = sizeof(*response);

  if (response == NULL) {
    CHPP_LOG_OOM();
    error = CHPP_APP_ERROR_OOM;
  } else {
    response->params.capabilities = wwanServiceContext->api->getCapabilities();

    CHPP_LOGD("chppWwanServiceGetCapabilities returning 0x%" PRIx32
              ", %" PRIuSIZE " bytes",
              response->params.capabilities, responseLen);
    chppSendTimestampedResponseOrFail(wwanServiceContext->service.appContext,
                                      &wwanServiceContext->getCapabilities,
                                      response, responseLen);
  }

  return error;
}

/**
 * Query information about the current serving cell and its neighbors in
 * response to a client request. This does not perform a network scan, but
 * should return state from the current network registration data stored in the
 * cellular modem.
 *
 * This function returns an error code synchronously. The requested cellular
 * information shall be returned asynchronously to the client via the
 * chppPlatformWwanCellInfoResultEvent() service response.
 *
 * @param serviceContext Maintains status for each service instance.
 * @param requestHeader App layer header of the request.
 *
 * @return Indicates the result of this function call.
 */
static enum ChppAppErrorCode chppWwanServiceGetCellInfoAsync(
    struct ChppWwanServiceState *wwanServiceContext,
    struct ChppAppHeader *requestHeader) {
  UNUSED_VAR(requestHeader);

  enum ChppAppErrorCode error = CHPP_APP_ERROR_NONE;

  if (!wwanServiceContext->api->requestCellInfo()) {
    CHPP_LOGE(
        "WWAN requestCellInfo PAL API failed. Unable to register for callback");
    error = CHPP_APP_ERROR_UNSPECIFIED;
  }

  return error;
}

/**
 * PAL callback to provide the result of a prior Request Cell Info
 * (cellInfoResultCallback).
 *
 * @param result Scan results.
 */
static void chppWwanServiceCellInfoResultCallback(
    struct chreWwanCellInfoResult *result) {
  // Recover state
  struct ChppIncomingRequestState *inReqState =
      &gWwanServiceContext.getCellInfoAsync;
  struct ChppWwanServiceState *wwanServiceContext =
      container_of(inReqState, struct ChppWwanServiceState, getCellInfoAsync);

  // Craft response per parser script
  struct ChppWwanCellInfoResultWithHeader *response = NULL;
  size_t responseLen = 0;
  if (!chppWwanCellInfoResultFromChre(result, &response, &responseLen)) {
    CHPP_LOGE("CellInfo conversion failed (OOM?) ID=%" PRIu8,
              inReqState->transaction);

    response = chppMalloc(sizeof(struct ChppAppHeader));
    if (response == NULL) {
      CHPP_LOG_OOM();
    } else {
      responseLen = sizeof(struct ChppAppHeader);
    }
  }

  if (response != NULL) {
    response->header.handle = wwanServiceContext->service.handle;
    response->header.type = CHPP_MESSAGE_TYPE_SERVICE_RESPONSE;
    response->header.transaction = inReqState->transaction;
    response->header.error = (responseLen > sizeof(struct ChppAppHeader))
                                 ? CHPP_APP_ERROR_NONE
                                 : CHPP_APP_ERROR_CONVERSION_FAILED;
    response->header.command = CHPP_WWAN_GET_CELLINFO_ASYNC;

    chppSendTimestampedResponseOrFail(wwanServiceContext->service.appContext,
                                      inReqState, response, responseLen);
  }

  gWwanServiceContext.api->releaseCellInfoResult(result);
}

/************************************************
 *  Public Functions
 ***********************************************/

void chppRegisterWwanService(struct ChppAppState *appContext) {
  gWwanServiceContext.api = chrePalWwanGetApi(CHPP_PAL_WWAN_API_VERSION);

  if (gWwanServiceContext.api == NULL) {
    CHPP_DEBUG_ASSERT_LOG(false,
                          "WWAN PAL API incompatible. Cannot register service");

  } else {
    chppRegisterService(appContext, (void *)&gWwanServiceContext,
                        &gWwanServiceContext.service, NULL /*outReqStates*/,
                        &kWwanServiceConfig);
    CHPP_DEBUG_ASSERT(gWwanServiceContext.service.handle);
  }
}

void chppDeregisterWwanService(struct ChppAppState *appContext) {
  // TODO

  UNUSED_VAR(appContext);
}