gecko-dev/netwerk/base/Tickler.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "Tickler.h"

#ifdef MOZ_USE_WIFI_TICKLER
#  include "nsComponentManagerUtils.h"
#  include "nsINamed.h"
#  include "nsServiceManagerUtils.h"
#  include "nsThreadUtils.h"
#  include "prnetdb.h"

#  include "mozilla/java/GeckoAppShellWrappers.h"
#  include "mozilla/jni/Utils.h"

namespace mozilla {
namespace net {

NS_IMPL_ISUPPORTS(Tickler, nsISupportsWeakReference, Tickler)

Tickler::Tickler()
    : mLock("Tickler::mLock"),
      mActive(false),
      mCanceled(false),
      mEnabled(false),
      mDelay(16),
      mDuration(TimeDuration::FromMilliseconds(400)),
      mFD(nullptr) {
  MOZ_ASSERT(NS_IsMainThread());
}

Tickler::~Tickler() {
  // non main thread uses of the tickler should hold weak
  // references to it if they must hold a reference at all
  MOZ_ASSERT(NS_IsMainThread());

  if (mThread) {
    mThread->AsyncShutdown();
    mThread = nullptr;
  }

  if (mTimer) mTimer->Cancel();
  if (mFD) PR_Close(mFD);
}

nsresult Tickler::Init() {
  if (!XRE_IsParentProcess()) {
    return NS_ERROR_FAILURE;
  }

  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(!mTimer);
  MOZ_ASSERT(!mActive);
  MOZ_ASSERT(!mThread);
  MOZ_ASSERT(!mFD);

  if (jni::IsAvailable()) {
    java::GeckoAppShell::EnableNetworkNotifications();
  }

  mFD = PR_OpenUDPSocket(PR_AF_INET);
  if (!mFD) return NS_ERROR_FAILURE;

  // make sure new socket has a ttl of 1
  // failure is not fatal.
  PRSocketOptionData opt;
  opt.option = PR_SockOpt_IpTimeToLive;
  opt.value.ip_ttl = 1;
  PR_SetSocketOption(mFD, &opt);

  nsresult rv = NS_NewNamedThread("wifi tickler", getter_AddRefs(mThread));
  if (NS_FAILED(rv)) return rv;

  nsCOMPtr<nsITimer> tmpTimer = NS_NewTimer(mThread);
  if (!tmpTimer) return NS_ERROR_OUT_OF_MEMORY;

  mTimer.swap(tmpTimer);

  mAddr.inet.family = PR_AF_INET;
  mAddr.inet.port = PR_htons(4886);
  mAddr.inet.ip = 0;

  return NS_OK;
}

void Tickler::Tickle() {
  MutexAutoLock lock(mLock);
  MOZ_ASSERT(mThread);
  mLastTickle = TimeStamp::Now();
  if (!mActive) MaybeStartTickler();
}

void Tickler::PostCheckTickler() {
  mLock.AssertCurrentThreadOwns();
  mThread->Dispatch(NewRunnableMethod("net::Tickler::CheckTickler", this,
                                      &Tickler::CheckTickler),
                    NS_DISPATCH_NORMAL);
  return;
}

void Tickler::MaybeStartTicklerUnlocked() {
  MutexAutoLock lock(mLock);
  MaybeStartTickler();
}

void Tickler::MaybeStartTickler() {
  mLock.AssertCurrentThreadOwns();
  if (!NS_IsMainThread()) {
    NS_DispatchToMainThread(
        NewRunnableMethod("net::Tickler::MaybeStartTicklerUnlocked", this,
                          &Tickler::MaybeStartTicklerUnlocked));
    return;
  }

  if (!mPrefs) mPrefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
  if (mPrefs) {
    int32_t val;
    bool boolVal;

    if (NS_SUCCEEDED(
            mPrefs->GetBoolPref("network.tickle-wifi.enabled", &boolVal)))
      mEnabled = boolVal;

    if (NS_SUCCEEDED(
            mPrefs->GetIntPref("network.tickle-wifi.duration", &val))) {
      if (val < 1) val = 1;
      if (val > 100000) val = 100000;
      mDuration = TimeDuration::FromMilliseconds(val);
    }

    if (NS_SUCCEEDED(mPrefs->GetIntPref("network.tickle-wifi.delay", &val))) {
      if (val < 1) val = 1;
      if (val > 1000) val = 1000;
      mDelay = static_cast<uint32_t>(val);
    }
  }

  PostCheckTickler();
}

void Tickler::CheckTickler() {
  MutexAutoLock lock(mLock);
  MOZ_ASSERT(mThread == NS_GetCurrentThread());

  bool shouldRun =
      (!mCanceled) && ((TimeStamp::Now() - mLastTickle) <= mDuration);

  if ((shouldRun && mActive) || (!shouldRun && !mActive))
    return;  // no change in state

  if (mActive)
    StopTickler();
  else
    StartTickler();
}

void Tickler::Cancel() {
  MutexAutoLock lock(mLock);
  MOZ_ASSERT(NS_IsMainThread());
  mCanceled = true;
  if (mThread) PostCheckTickler();
}

void Tickler::StopTickler() {
  mLock.AssertCurrentThreadOwns();
  MOZ_ASSERT(mThread == NS_GetCurrentThread());
  MOZ_ASSERT(mTimer);
  MOZ_ASSERT(mActive);

  mTimer->Cancel();
  mActive = false;
}

class TicklerTimer final : public nsITimerCallback, public nsINamed {
  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSITIMERCALLBACK

  explicit TicklerTimer(Tickler* aTickler) {
    mTickler = do_GetWeakReference(aTickler);
  }

  // nsINamed
  NS_IMETHOD GetName(nsACString& aName) override {
    aName.AssignLiteral("TicklerTimer");
    return NS_OK;
  }

 private:
  ~TicklerTimer() {}

  nsWeakPtr mTickler;
};

void Tickler::StartTickler() {
  mLock.AssertCurrentThreadOwns();
  MOZ_ASSERT(mThread == NS_GetCurrentThread());
  MOZ_ASSERT(!mActive);
  MOZ_ASSERT(mTimer);

  if (NS_SUCCEEDED(mTimer->InitWithCallback(new TicklerTimer(this),
                                            mEnabled ? mDelay : 1000,
                                            nsITimer::TYPE_REPEATING_SLACK)))
    mActive = true;
}

// argument should be in network byte order
void Tickler::SetIPV4Address(uint32_t address) { mAddr.inet.ip = address; }

// argument should be in network byte order
void Tickler::SetIPV4Port(uint16_t port) { mAddr.inet.port = port; }

NS_IMPL_ISUPPORTS(TicklerTimer, nsITimerCallback, nsINamed)

NS_IMETHODIMP TicklerTimer::Notify(nsITimer* timer) {
  RefPtr<Tickler> tickler = do_QueryReferent(mTickler);
  if (!tickler) return NS_ERROR_FAILURE;
  MutexAutoLock lock(tickler->mLock);

  if (!tickler->mFD) {
    tickler->StopTickler();
    return NS_ERROR_FAILURE;
  }

  if (tickler->mCanceled ||
      ((TimeStamp::Now() - tickler->mLastTickle) > tickler->mDuration)) {
    tickler->StopTickler();
    return NS_OK;
  }

  if (!tickler->mEnabled) return NS_OK;

  PR_SendTo(tickler->mFD, "", 0, 0, &tickler->mAddr, 0);
  return NS_OK;
}

}  // namespace net
}  // namespace mozilla

#else  // not defined MOZ_USE_WIFI_TICKLER

namespace mozilla {
namespace net {
NS_IMPL_ISUPPORTS0(Tickler)
}  // namespace net
}  // namespace mozilla

#endif  // defined MOZ_USE_WIFI_TICKLER