netwerk/dns/nsEffectiveTLDService.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 EffectiveTLDService_h
   7 #define EffectiveTLDService_h
   8
   9 #include "nsIEffectiveTLDService.h"
  10
  11 #include "mozilla/AutoMemMap.h"
  12 #include "mozilla/Attributes.h"
  13 #include "mozilla/Dafsa.h"
  14 #include "mozilla/Maybe.h"
  15 #include "mozilla/MemoryReporting.h"
  16 #include "mozilla/MruCache.h"
  17 #include "mozilla/RWLock.h"
  18
  19 #include "nsCOMPtr.h"
  20 #include "nsHashKeys.h"
  21 #include "nsIMemoryReporter.h"
  22 #include "nsIObserver.h"
  23 #include "nsString.h"
  24
  25 class nsIIDNService;
  26
  27 class nsEffectiveTLDService final : public nsIEffectiveTLDService,
  28                                     public nsIObserver,
  29                                     public nsIMemoryReporter {
  30  public:
  31   NS_DECL_THREADSAFE_ISUPPORTS
  32   NS_DECL_NSIEFFECTIVETLDSERVICE
  33   NS_DECL_NSIMEMORYREPORTER
  34   NS_DECL_NSIOBSERVER
  35
  36   nsEffectiveTLDService();
  37   nsresult Init();
  38
  39   static nsEffectiveTLDService* GetInstance();
  40
  41   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf);
  42
  43  private:
  44   nsresult GetBaseDomainInternal(nsCString& aHostname, int32_t aAdditionalParts,
  45                                  bool aOnlyKnownPublicSuffix,
  46                                  nsACString& aBaseDomain);
  47   nsresult NormalizeHostname(nsCString& aHostname);
  48   ~nsEffectiveTLDService();
  49
  50   // Only set in `Init()` which is called during service construction.
  51   nsCOMPtr<nsIIDNService> mIDNService;
  52
  53   // The DAFSA provides a compact encoding of the rather large eTLD list.
  54   mozilla::Maybe<mozilla::Dafsa> mGraph MOZ_GUARDED_BY(mGraphLock);
  55
  56   // Memory map used for a new updated dafsa
  57   mozilla::loader::AutoMemMap mDafsaMap MOZ_GUARDED_BY(mGraphLock);
  58
  59   // Lock for mGraph and mDafsaMap
  60   mozilla::RWLock mGraphLock;
  61
  62   // Note that the cache entries here can record entries that were cached
  63   // successfully or unsuccessfully.  mResult must be checked before using an
  64   // entry.  If it's a success error code, the cache entry is valid and can be
  65   // used.
  66   struct TLDCacheEntry {
  67     nsCString mHost;
  68     nsCString mBaseDomain;
  69     nsresult mResult;
  70   };
  71
  72   // We use a small most recently used cache to compensate for DAFSA lookups
  73   // being slightly slower than a binary search on a larger table of strings.
  74   //
  75   // We first check the cache for a matching result and avoid a DAFSA lookup
  76   // if a match is found. Otherwise we lookup the domain in the DAFSA and then
  77   // cache the result. During standard browsing the same domains are repeatedly
  78   // fed into |GetBaseDomainInternal| so this ends up being an effective
  79   // mitigation getting about a 99% hit rate with four tabs open.
  80   struct TldCache
  81       : public mozilla::MruCache<nsACString, TLDCacheEntry, TldCache> {
  82     static mozilla::HashNumber Hash(const nsACString& aKey) {
  83       return mozilla::HashString(aKey);
  84     }
  85     static bool Match(const nsACString& aKey, const TLDCacheEntry& aVal) {
  86       return aKey == aVal.mHost;
  87     }
  88   };
  89
  90   // NOTE: Only used on the main thread, so not guarded by mGraphLock.
  91   TldCache mMruTable;
  92 };
  93
  94 #endif  // EffectiveTLDService_h