netwerk/base/Tickler.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef mozilla_net_Tickler_h
   7 #define mozilla_net_Tickler_h
   8
   9 // The tickler sends a regular 0 byte UDP heartbeat out to a
  10 // particular address for a short time after it has been touched. This
  11 // is used on some mobile wifi chipsets to mitigate Power Save Polling
  12 // (PSP) Mode when we are anticipating a response packet
  13 // soon. Typically PSP adds 100ms of latency to a read event because
  14 // the packet delivery is not triggered until the 802.11 beacon is
  15 // delivered to the host (100ms is the standard Access Point
  16 // configuration for the beacon interval.) Requesting a frequent
  17 // transmission and getting a CTS frame from the AP at least that
  18 // frequently allows for low latency receives when we have reason to
  19 // expect them (e.g a SYN-ACK).
  20 //
  21 // The tickler is used to allow RTT based phases of web transport to
  22 // complete quickly when on wifi - ARP, DNS, TCP handshake, SSL
  23 // handshake, HTTP headers, and the TCP slow start phase. The
  24 // transaction is given up to 400 miliseconds by default to get
  25 // through those phases before the tickler is disabled.
  26 //
  27 // The tickler only applies to wifi on mobile right now. Hopefully it
  28 // can also be restricted to particular handset models in the future.
  29
  30 #if defined(ANDROID) && !defined(MOZ_PROXY_BYPASS_PROTECTION)
  31 #  define MOZ_USE_WIFI_TICKLER
  32 #endif
  33
  34 #include "mozilla/Attributes.h"
  35 #include "nsISupports.h"
  36 #include <stdint.h>
  37
  38 #ifdef MOZ_USE_WIFI_TICKLER
  39 #  include "mozilla/Mutex.h"
  40 #  include "mozilla/TimeStamp.h"
  41 #  include "nsISupports.h"
  42 #  include "nsIThread.h"
  43 #  include "nsITimer.h"
  44 #  include "nsWeakReference.h"
  45 #  include "prio.h"
  46
  47 class nsIPrefBranch;
  48 #endif
  49
  50 namespace mozilla {
  51 namespace net {
  52
  53 #ifdef MOZ_USE_WIFI_TICKLER
  54
  55 // 8f769ed6-207c-4af9-9f7e-9e832da3754e
  56 #  define NS_TICKLER_IID                               \
  57     {                                                  \
  58       0x8f769ed6, 0x207c, 0x4af9, {                    \
  59         0x9f, 0x7e, 0x9e, 0x83, 0x2d, 0xa3, 0x75, 0x4e \
  60       }                                                \
  61     }
  62
  63 class Tickler final : public nsSupportsWeakReference {
  64  public:
  65   NS_DECL_THREADSAFE_ISUPPORTS
  66   NS_DECLARE_STATIC_IID_ACCESSOR(NS_TICKLER_IID)
  67
  68   // These methods are main thread only
  69   Tickler();
  70   void Cancel();
  71   nsresult Init();
  72   void SetIPV4Address(uint32_t address);
  73   void SetIPV4Port(uint16_t port);
  74
  75   // Tickle the tickler to (re-)start the activity.
  76   // May call from any thread
  77   void Tickle();
  78
  79  private:
  80   ~Tickler();
  81
  82   friend class TicklerTimer;
  83   Mutex mLock MOZ_UNANNOTATED;
  84   nsCOMPtr<nsIThread> mThread;
  85   nsCOMPtr<nsITimer> mTimer;
  86   nsCOMPtr<nsIPrefBranch> mPrefs;
  87
  88   bool mActive;
  89   bool mCanceled;
  90   bool mEnabled;
  91   uint32_t mDelay;
  92   TimeDuration mDuration;
  93   PRFileDesc* mFD;
  94
  95   TimeStamp mLastTickle;
  96   PRNetAddr mAddr;
  97
  98   // These functions may be called from any thread
  99   void PostCheckTickler();
 100   void MaybeStartTickler();
 101   void MaybeStartTicklerUnlocked();
 102
 103   // Tickler thread only
 104   void CheckTickler();
 105   void StartTickler();
 106   void StopTickler();
 107 };
 108
 109 NS_DEFINE_STATIC_IID_ACCESSOR(Tickler, NS_TICKLER_IID)
 110
 111 #else  // not defined MOZ_USE_WIFI_TICKLER
 112
 113 class Tickler final : public nsISupports {
 114   ~Tickler() = default;
 115
 116  public:
 117   NS_DECL_THREADSAFE_ISUPPORTS
 118
 119   Tickler() = default;
 120   nsresult Init() { return NS_ERROR_NOT_IMPLEMENTED; }
 121   void Cancel() {}
 122   void SetIPV4Address(uint32_t){};
 123   void SetIPV4Port(uint16_t) {}
 124   void Tickle() {}
 125 };
 126
 127 #endif  // defined MOZ_USE_WIFI_TICKLER
 128
 129 }  // namespace net
 130 }  // namespace mozilla
 131
 132 #endif  // mozilla_net_Tickler_h