android10/system/chre/apps/wifi_world/wifi_world.cc

/*
 * Copyright (C) 2017 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 <chre.h>
#include <cinttypes>

#include "chre/util/macros.h"
#include "chre/util/nanoapp/log.h"
#include "chre/util/time.h"
#include "chre/util/nanoapp/wifi.h"

using chre::kOneMillisecondInNanoseconds;
using chre::Nanoseconds;
using chre::Seconds;

#define LOG_TAG "[WifiWorld]"

//#define WIFI_WORLD_VERBOSE_WIFI_RESULT_LOGS

#ifdef CHRE_NANOAPP_INTERNAL
namespace chre {
namespace {
#endif  // CHRE_NANOAPP_INTERNAL

namespace {

//! A dummy cookie to pass into the configure scan monitoring async request.
constexpr uint32_t kScanMonitoringCookie = 0x1337;

//! A dummy cookie to pass into request scan async.
constexpr uint32_t kOnDemandScanCookie = 0xcafe;

//! The interval for on-demand wifi scans.
constexpr Nanoseconds kWifiScanInterval = Nanoseconds(Seconds(10));

//! A handle for the cyclic timer to request periodic on-demand wifi-scans.
uint32_t gWifiScanTimerHandle;

//! A global instance of wifi capabilities to use when reqeuesting wifi
//! functionality. This is populated at startup.
uint32_t gWifiCapabilities;

//! The last time in nanoseconds a wifi scan request was sucessfully made.
uint64_t gLastRequestTimeNs = 0;

//! True if CHRE_WIFI_REQUEST_TYPE_REQUEST_SCAN mode is requested.
bool gPendingOnDemandScan = false;

//! Accumulating count of the scan request results so far.
uint32_t gScanResultAcc = 0;

//! The currently requested on-demand wifi scan parameters.
chreWifiScanParams gWifiScanParams = {};

//! The sequence of on-demand wifi scan types to request for.
constexpr chreWifiScanType gWifiScanTypes[] = {
  CHRE_WIFI_SCAN_TYPE_ACTIVE,
  CHRE_WIFI_SCAN_TYPE_ACTIVE_PLUS_PASSIVE_DFS,
  CHRE_WIFI_SCAN_TYPE_PASSIVE
};

//! The index of the next wifi scan type to request for.
uint8_t gScanTypeIndex = 0;

/**
 * Logs a CHRE wifi scan result.
 *
 * @param result the scan result to log.
 */
void logChreWifiResult(const chreWifiScanResult& result) {
  const char *ssidStr = "<non-printable>";
  char ssidBuffer[chre::kMaxSsidStrLen];
  if (result.ssidLen == 0) {
    ssidStr = "<empty>";
  } else if (chre::parseSsidToStr(ssidBuffer, sizeof(ssidBuffer),
                                  result.ssid, result.ssidLen)) {
    ssidStr = ssidBuffer;
  }

  LOGI("Found network with SSID: %s", ssidStr);
#ifdef WIFI_WORLD_VERBOSE_WIFI_RESULT_LOGS
  const char *bssidStr = "<non-printable>";
  char bssidBuffer[chre::kBssidStrLen];
  if (chre::parseBssidToStr(result.bssid, bssidBuffer, sizeof(bssidBuffer))) {
    bssidStr = bssidBuffer;
  }

  LOGI("  age (ms): %" PRIu32, result.ageMs);
  LOGI("  capability info: %" PRIx16, result.capabilityInfo);
  LOGI("  bssid: %s", bssidStr);
  LOGI("  flags: %" PRIx8, result.flags);
  LOGI("  rssi: %" PRId8 "dBm", result.rssi);
  LOGI("  band: %s (%" PRIu8 ")",
       chre::parseChreWifiBand(result.band), result.band);
  LOGI("  primary channel: %" PRIu32, result.primaryChannel);
  LOGI("  center frequency primary: %" PRIu32, result.centerFreqPrimary);
  LOGI("  center frequency secondary: %" PRIu32, result.centerFreqSecondary);
  LOGI("  channel width: %" PRIu8, result.channelWidth);
  LOGI("  security mode: %" PRIx8, result.securityMode);
#endif  // WIFI_WORLD_VERBOSE_WIFI_RESULT_LOGS
}

/**
 * Requests a delayed wifi scan using a one-shot timer. The interval is
 * specified as a constant at the top of this file.
 */
void requestDelayedWifiScan() {
  if (gWifiCapabilities & CHRE_WIFI_CAPABILITIES_ON_DEMAND_SCAN) {
    // Schedule a timer to send an active wifi scan.
    gWifiScanTimerHandle = chreTimerSet(kWifiScanInterval.toRawNanoseconds(),
                                        &gWifiScanTimerHandle /* data */,
                                        true /* oneShot */);
    if (gWifiScanTimerHandle == CHRE_TIMER_INVALID) {
      LOGE("Failed to set timer for delayed wifi scan");
    } else {
      LOGI("Set a timer to request a WiFi scan");
    }
  }
}

/**
 * Handles the result of an asynchronous request for a wifi resource.
 *
 * @param result a pointer to the event structure containing the result of the
 * request.
 */
void handleWifiAsyncResult(const chreAsyncResult *result) {
  if (result->requestType == CHRE_WIFI_REQUEST_TYPE_CONFIGURE_SCAN_MONITOR) {
    if (result->success) {
      LOGI("Successfully requested wifi scan monitoring");
    } else {
      LOGE("Error requesting wifi scan monitoring with %" PRIu8,
           result->errorCode);
    }

    if (result->cookie != &kScanMonitoringCookie) {
      LOGE("Scan monitoring request cookie mismatch");
    }
  } else if (result->requestType == CHRE_WIFI_REQUEST_TYPE_REQUEST_SCAN) {
    uint64_t timeSinceRequest = chreGetTime() - gLastRequestTimeNs;
    if (result->success) {
      LOGI("Successfully requested an on-demand wifi scan (response time %"
           PRIu64 " ms)", timeSinceRequest / kOneMillisecondInNanoseconds);
      gPendingOnDemandScan = true;
    } else {
      LOGE("Error requesting an on-demand wifi scan with %" PRIu8,
           result->errorCode);
    }

    if (result->cookie != &kOnDemandScanCookie) {
      LOGE("On-demand scan cookie mismatch");
    }

    requestDelayedWifiScan();
  } else {
    LOGE("Received invalid async result");
  }
}

/**
 * Handles a wifi scan event.
 *
 * @param event a pointer to the details of the wifi scan event.
 */
void handleWifiScanEvent(const chreWifiScanEvent *event) {
  LOGI("Received Wifi scan event of type %" PRIu8 " with %" PRIu8
       " results at %" PRIu64 "ns", event->scanType, event->resultCount,
       event->referenceTime);

  if (gPendingOnDemandScan) {
    uint64_t timeSinceRequest = chreGetTime() - gLastRequestTimeNs;
    LOGI("Time since scan request = %" PRIu64 " ms",
         timeSinceRequest / kOneMillisecondInNanoseconds);

    if (event->scanType != gWifiScanParams.scanType) {
      LOGE("Invalid scan event type (expected %" PRIu8 ", received %" PRIu8 ")",
           gWifiScanParams.scanType, event->scanType);
    }

    gScanResultAcc += event->resultCount;
    if (gScanResultAcc >= event->resultTotal) {
      gPendingOnDemandScan = false;
      gScanResultAcc = 0;
    }
  }

  for (uint8_t i = 0; i < event->resultCount; i++) {
    const chreWifiScanResult& result = event->results[i];
    logChreWifiResult(result);
  }
}

/**
 * Handles a timer event.
 *
 * @param eventData The cookie passed to the timer request.
 */
void handleTimerEvent(const void *eventData) {
  const uint32_t *timerHandle = static_cast<const uint32_t *>(eventData);
  if (*timerHandle == gWifiScanTimerHandle) {
    gWifiScanParams.scanType         = gWifiScanTypes[gScanTypeIndex];
    gWifiScanParams.maxScanAgeMs     = 5000;  // 5 seconds
    gWifiScanParams.frequencyListLen = 0;
    gWifiScanParams.ssidListLen      = 0;
    gScanTypeIndex = (gScanTypeIndex + 1) % ARRAY_SIZE(gWifiScanTypes);

    if (chreWifiRequestScanAsync(&gWifiScanParams, &kOnDemandScanCookie)) {
      LOGI("Requested a wifi scan successfully");
      gLastRequestTimeNs = chreGetTime();
    } else {
      LOGE("Failed to request a wifi scan");
    }
  } else {
    LOGE("Received invalid timer handle");
  }
}

}  // namespace

bool nanoappStart() {
  LOGI("App started as instance %" PRIu32, chreGetInstanceId());

  gWifiCapabilities = chreWifiGetCapabilities();
  LOGI("Detected WiFi support as: 0x%" PRIx32, gWifiCapabilities);

  if (gWifiCapabilities & CHRE_WIFI_CAPABILITIES_SCAN_MONITORING) {
    if (chreWifiConfigureScanMonitorAsync(true, &kScanMonitoringCookie)) {
      LOGI("Scan monitor enable request successful");
    } else {
      LOGE("Error sending scan monitoring request");
    }
  }

  requestDelayedWifiScan();
  return true;
}

void nanoappHandleEvent(uint32_t senderInstanceId,
                        uint16_t eventType,
                        const void *eventData) {
  switch (eventType) {
    case CHRE_EVENT_WIFI_ASYNC_RESULT:
      handleWifiAsyncResult(static_cast<const chreAsyncResult *>(eventData));
      break;
    case CHRE_EVENT_WIFI_SCAN_RESULT:
      handleWifiScanEvent(static_cast<const chreWifiScanEvent *>(eventData));
      break;
    case CHRE_EVENT_TIMER:
      handleTimerEvent(eventData);
      break;
    default:
      LOGW("Unhandled event type %" PRIu16, eventType);
  }
}

void nanoappEnd() {
  LOGI("Wifi world app stopped");
}

#ifdef CHRE_NANOAPP_INTERNAL
}  // anonymous namespace
}  // namespace chre

#include "chre/util/nanoapp/app_id.h"
#include "chre/platform/static_nanoapp_init.h"

CHRE_STATIC_NANOAPP_INIT(WifiWorld, chre::kWifiWorldAppId, 0);
#endif  // CHRE_NANOAPP_INTERNAL