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 "nsAutoPtr.h"
  42 #  include "nsISupports.h"
  43 #  include "nsIThread.h"
  44 #  include "nsITimer.h"
  45 #  include "nsWeakReference.h"
  46 #  include "prio.h"
  47
  48 class nsIPrefBranch;
  49 #endif
  50
  51 namespace mozilla {
  52 namespace net {
  53
  54 #ifdef MOZ_USE_WIFI_TICKLER
  55
  56 // 8f769ed6-207c-4af9-9f7e-9e832da3754e
  57 #  define NS_TICKLER_IID                               \
  58     {                                                  \
  59       0x8f769ed6, 0x207c, 0x4af9, {                    \
  60         0x9f, 0x7e, 0x9e, 0x83, 0x2d, 0xa3, 0x75, 0x4e \
  61       }                                                \
  62     }
  63
  64 class Tickler final : public nsSupportsWeakReference {
  65  public:
  66   NS_DECL_THREADSAFE_ISUPPORTS
  67   NS_DECLARE_STATIC_IID_ACCESSOR(NS_TICKLER_IID)
  68
  69   // These methods are main thread only
  70   Tickler();
  71   void Cancel();
  72   nsresult Init();
  73   void SetIPV4Address(uint32_t address);
  74   void SetIPV4Port(uint16_t port);
  75
  76   // Tickle the tickler to (re-)start the activity.
  77   // May call from any thread
  78   void Tickle();
  79
  80  private:
  81   ~Tickler();
  82
  83   friend class TicklerTimer;
  84   Mutex mLock;
  85   nsCOMPtr<nsIThread> mThread;
  86   nsCOMPtr<nsITimer> mTimer;
  87   nsCOMPtr<nsIPrefBranch> mPrefs;
  88
  89   bool mActive;
  90   bool mCanceled;
  91   bool mEnabled;
  92   uint32_t mDelay;
  93   TimeDuration mDuration;
  94   PRFileDesc* mFD;
  95
  96   TimeStamp mLastTickle;
  97   PRNetAddr mAddr;
  98
  99   // These functions may be called from any thread
 100   void PostCheckTickler();
 101   void MaybeStartTickler();
 102   void MaybeStartTicklerUnlocked();
 103
 104   // Tickler thread only
 105   void CheckTickler();
 106   void StartTickler();
 107   void StopTickler();
 108 };
 109
 110 NS_DEFINE_STATIC_IID_ACCESSOR(Tickler, NS_TICKLER_IID)
 111
 112 #else  // not defined MOZ_USE_WIFI_TICKLER
 113
 114 class Tickler final : public nsISupports {
 115   ~Tickler() = default;
 116
 117  public:
 118   NS_DECL_THREADSAFE_ISUPPORTS
 119
 120   Tickler() = default;
 121   nsresult Init() { return NS_ERROR_NOT_IMPLEMENTED; }
 122   void Cancel() {}
 123   void SetIPV4Address(uint32_t){};
 124   void SetIPV4Port(uint16_t) {}
 125   void Tickle() {}
 126 };
 127
 128 #endif  // defined MOZ_USE_WIFI_TICKLER
 129
 130 }  // namespace net
 131 }  // namespace mozilla
 132
 133 #endif  // mozilla_net_Tickler_h