netwerk/dns/nsHostResolver.h

   1 /* vim:set ts=4 sw=2 sts=2 et cin: */
   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 nsHostResolver_h__
   7 #define nsHostResolver_h__
   8
   9 #include "nscore.h"
  10 #include "prnetdb.h"
  11 #include "PLDHashTable.h"
  12 #include "mozilla/CondVar.h"
  13 #include "mozilla/DataMutex.h"
  14 #include "nsISupportsImpl.h"
  15 #include "nsIDNSListener.h"
  16 #include "nsTArray.h"
  17 #include "GetAddrInfo.h"
  18 #include "HostRecordQueue.h"
  19 #include "mozilla/net/DNS.h"
  20 #include "mozilla/net/DashboardTypes.h"
  21 #include "mozilla/Atomics.h"
  22 #include "mozilla/TimeStamp.h"
  23 #include "mozilla/UniquePtr.h"
  24 #include "nsHostRecord.h"
  25 #include "nsRefPtrHashtable.h"
  26 #include "nsIThreadPool.h"
  27 #include "mozilla/net/NetworkConnectivityService.h"
  28 #include "mozilla/net/DNSByTypeRecord.h"
  29 #include "mozilla/Maybe.h"
  30 #include "mozilla/StaticPrefs_network.h"
  31
  32 namespace mozilla {
  33 namespace net {
  34 class TRR;
  35 class TRRQuery;
  36
  37 static inline uint32_t MaxResolverThreadsAnyPriority() {
  38   return StaticPrefs::network_dns_max_any_priority_threads();
  39 }
  40
  41 static inline uint32_t MaxResolverThreadsHighPriority() {
  42   return StaticPrefs::network_dns_max_high_priority_threads();
  43 }
  44
  45 static inline uint32_t MaxResolverThreads() {
  46   return MaxResolverThreadsAnyPriority() + MaxResolverThreadsHighPriority();
  47 }
  48
  49 }  // namespace net
  50 }  // namespace mozilla
  51
  52 #define TRR_DISABLED(x)                       \
  53   (((x) == nsIDNSService::MODE_NATIVEONLY) || \
  54    ((x) == nsIDNSService::MODE_TRROFF))
  55
  56 extern mozilla::Atomic<bool, mozilla::Relaxed> gNativeIsLocalhost;
  57
  58 #define MAX_NON_PRIORITY_REQUESTS 150
  59
  60 class AHostResolver {
  61  public:
  62   AHostResolver() = default;
  63   virtual ~AHostResolver() = default;
  64   NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
  65
  66   enum LookupStatus {
  67     LOOKUP_OK,
  68     LOOKUP_RESOLVEAGAIN,
  69   };
  70
  71   virtual LookupStatus CompleteLookup(nsHostRecord*, nsresult,
  72                                       mozilla::net::AddrInfo*, bool pb,
  73                                       const nsACString& aOriginsuffix,
  74                                       mozilla::net::TRRSkippedReason aReason,
  75                                       mozilla::net::TRR*) = 0;
  76   virtual LookupStatus CompleteLookupByType(
  77       nsHostRecord*, nsresult, mozilla::net::TypeRecordResultType& aResult,
  78       uint32_t aTtl, bool pb) = 0;
  79   virtual nsresult GetHostRecord(const nsACString& host,
  80                                  const nsACString& aTrrServer, uint16_t type,
  81                                  nsIDNSService::DNSFlags flags, uint16_t af,
  82                                  bool pb, const nsCString& originSuffix,
  83                                  nsHostRecord** result) {
  84     return NS_ERROR_FAILURE;
  85   }
  86   virtual nsresult TrrLookup_unlocked(nsHostRecord*,
  87                                       mozilla::net::TRR* pushedTRR = nullptr) {
  88     return NS_ERROR_FAILURE;
  89   }
  90   virtual void MaybeRenewHostRecord(nsHostRecord* aRec) {}
  91 };
  92
  93 /**
  94  * nsHostResolver - an asynchronous host name resolver.
  95  */
  96 class nsHostResolver : public nsISupports, public AHostResolver {
  97   using CondVar = mozilla::CondVar;
  98   using Mutex = mozilla::Mutex;
  99
 100  public:
 101   NS_DECL_THREADSAFE_ISUPPORTS
 102
 103   /**
 104    * creates an addref'd instance of a nsHostResolver object.
 105    */
 106   static nsresult Create(uint32_t maxCacheEntries,  // zero disables cache
 107                          uint32_t defaultCacheEntryLifetime,  // seconds
 108                          uint32_t defaultGracePeriod,         // seconds
 109                          nsHostResolver** result);
 110
 111   /**
 112    * Set (new) cache limits.
 113    */
 114   void SetCacheLimits(uint32_t maxCacheEntries,  // zero disables cache
 115                       uint32_t defaultCacheEntryLifetime,  // seconds
 116                       uint32_t defaultGracePeriod);        // seconds
 117
 118   /**
 119    * puts the resolver in the shutdown state, which will cause any pending
 120    * callbacks to be detached.  any future calls to ResolveHost will fail.
 121    */
 122   void Shutdown();
 123
 124   /**
 125    * resolve the given hostname and originAttributes asynchronously.  the caller
 126    * can synthesize a synchronous host lookup using a lock and a cvar.  as noted
 127    * above the callback will occur re-entrantly from an unspecified thread.  the
 128    * host lookup cannot be canceled (cancelation can be layered above this by
 129    * having the callback implementation return without doing anything).
 130    */
 131   nsresult ResolveHost(const nsACString& aHost, const nsACString& trrServer,
 132                        int32_t aPort, uint16_t type,
 133                        const mozilla::OriginAttributes& aOriginAttributes,
 134                        nsIDNSService::DNSFlags flags, uint16_t af,
 135                        nsResolveHostCallback* callback);
 136
 137   nsHostRecord* InitRecord(const nsHostKey& key);
 138   mozilla::net::NetworkConnectivityService* GetNCS() {
 139     return mNCS;
 140   }  // This is actually a singleton
 141
 142   /**
 143    * return a resolved hard coded loopback dns record for the specified key
 144    */
 145   already_AddRefed<nsHostRecord> InitLoopbackRecord(const nsHostKey& key,
 146                                                     nsresult* aRv);
 147
 148   /**
 149    * removes the specified callback from the nsHostRecord for the given
 150    * hostname, originAttributes, flags, and address family.  these parameters
 151    * should correspond to the parameters passed to ResolveHost.  this function
 152    * executes the callback if the callback is still pending with the given
 153    * status.
 154    */
 155   void DetachCallback(const nsACString& hostname, const nsACString& trrServer,
 156                       uint16_t type,
 157                       const mozilla::OriginAttributes& aOriginAttributes,
 158                       nsIDNSService::DNSFlags flags, uint16_t af,
 159                       nsResolveHostCallback* callback, nsresult status);
 160
 161   /**
 162    * Cancels an async request associated with the hostname, originAttributes,
 163    * flags, address family and listener.  Cancels first callback found which
 164    * matches these criteria.  These parameters should correspond to the
 165    * parameters passed to ResolveHost.  If this is the last callback associated
 166    * with the host record, it is removed from any request queues it might be on.
 167    */
 168   void CancelAsyncRequest(const nsACString& host, const nsACString& trrServer,
 169                           uint16_t type,
 170                           const mozilla::OriginAttributes& aOriginAttributes,
 171                           nsIDNSService::DNSFlags flags, uint16_t af,
 172                           nsIDNSListener* aListener, nsresult status);
 173   /**
 174    * values for the flags parameter passed to ResolveHost and DetachCallback
 175    * that may be bitwise OR'd together.
 176    *
 177    * NOTE: in this implementation, these flags correspond exactly in value
 178    *       to the flags defined on nsIDNSService.
 179    */
 180   enum {
 181     RES_BYPASS_CACHE = nsIDNSService::RESOLVE_BYPASS_CACHE,
 182     RES_CANON_NAME = nsIDNSService::RESOLVE_CANONICAL_NAME,
 183     RES_PRIORITY_MEDIUM = nsHostRecord::DNS_PRIORITY_MEDIUM,
 184     RES_PRIORITY_LOW = nsHostRecord::DNS_PRIORITY_LOW,
 185     RES_SPECULATE = nsIDNSService::RESOLVE_SPECULATE,
 186     // RES_DISABLE_IPV6 = nsIDNSService::RESOLVE_DISABLE_IPV6, // Not used
 187     RES_OFFLINE = nsIDNSService::RESOLVE_OFFLINE,
 188     // RES_DISABLE_IPv4 = nsIDNSService::RESOLVE_DISABLE_IPV4, // Not Used
 189     RES_ALLOW_NAME_COLLISION = nsIDNSService::RESOLVE_ALLOW_NAME_COLLISION,
 190     RES_DISABLE_TRR = nsIDNSService::RESOLVE_DISABLE_TRR,
 191     RES_REFRESH_CACHE = nsIDNSService::RESOLVE_REFRESH_CACHE,
 192     RES_IP_HINT = nsIDNSService::RESOLVE_IP_HINT
 193   };
 194
 195   size_t SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
 196
 197   /**
 198    * Flush the DNS cache.
 199    */
 200   void FlushCache(bool aTrrToo);
 201
 202   LookupStatus CompleteLookup(nsHostRecord*, nsresult, mozilla::net::AddrInfo*,
 203                               bool pb, const nsACString& aOriginsuffix,
 204                               mozilla::net::TRRSkippedReason aReason,
 205                               mozilla::net::TRR* aTRRRequest) override;
 206   LookupStatus CompleteLookupByType(nsHostRecord*, nsresult,
 207                                     mozilla::net::TypeRecordResultType& aResult,
 208                                     uint32_t aTtl, bool pb) override;
 209   nsresult GetHostRecord(const nsACString& host, const nsACString& trrServer,
 210                          uint16_t type, nsIDNSService::DNSFlags flags,
 211                          uint16_t af, bool pb, const nsCString& originSuffix,
 212                          nsHostRecord** result) override;
 213   nsresult TrrLookup_unlocked(nsHostRecord*,
 214                               mozilla::net::TRR* pushedTRR = nullptr) override;
 215   static nsIDNSService::ResolverMode Mode();
 216
 217   virtual void MaybeRenewHostRecord(nsHostRecord* aRec) override;
 218
 219   // Records true if the TRR service is enabled for the record's effective
 220   // TRR mode. Also records the TRRSkipReason when the TRR service is not
 221   // available/enabled.
 222   bool TRRServiceEnabledForRecord(nsHostRecord* aRec) MOZ_REQUIRES(mLock);
 223
 224  private:
 225   explicit nsHostResolver(uint32_t maxCacheEntries,
 226                           uint32_t defaultCacheEntryLifetime,
 227                           uint32_t defaultGracePeriod);
 228   virtual ~nsHostResolver();
 229
 230   bool DoRetryTRR(AddrHostRecord* aAddrRec,
 231                   const mozilla::MutexAutoLock& aLock);
 232   bool MaybeRetryTRRLookup(
 233       AddrHostRecord* aAddrRec, nsresult aFirstAttemptStatus,
 234       mozilla::net::TRRSkippedReason aFirstAttemptSkipReason,
 235       nsresult aChannelStatus, const mozilla::MutexAutoLock& aLock);
 236
 237   LookupStatus CompleteLookupLocked(nsHostRecord*, nsresult,
 238                                     mozilla::net::AddrInfo*, bool pb,
 239                                     const nsACString& aOriginsuffix,
 240                                     mozilla::net::TRRSkippedReason aReason,
 241                                     mozilla::net::TRR* aTRRRequest,
 242                                     const mozilla::MutexAutoLock& aLock)
 243       MOZ_REQUIRES(mLock);
 244   LookupStatus CompleteLookupByTypeLocked(
 245       nsHostRecord*, nsresult, mozilla::net::TypeRecordResultType& aResult,
 246       uint32_t aTtl, bool pb, const mozilla::MutexAutoLock& aLock)
 247       MOZ_REQUIRES(mLock);
 248   nsresult Init();
 249   static void ComputeEffectiveTRRMode(nsHostRecord* aRec);
 250   nsresult NativeLookup(nsHostRecord* aRec,
 251                         const mozilla::MutexAutoLock& aLock);
 252   nsresult TrrLookup(nsHostRecord*, const mozilla::MutexAutoLock& aLock,
 253                      mozilla::net::TRR* pushedTRR = nullptr);
 254
 255   // Kick-off a name resolve operation, using native resolver and/or TRR
 256   nsresult NameLookup(nsHostRecord* aRec, const mozilla::MutexAutoLock& aLock);
 257   bool GetHostToLookup(AddrHostRecord** result);
 258   void MaybeRenewHostRecordLocked(nsHostRecord* aRec,
 259                                   const mozilla::MutexAutoLock& aLock)
 260       MOZ_REQUIRES(mLock);
 261
 262   // Cancels host records in the pending queue and also
 263   // calls CompleteLookup with the NS_ERROR_ABORT result code.
 264   void ClearPendingQueue(mozilla::LinkedList<RefPtr<nsHostRecord>>& aPendingQ);
 265   nsresult ConditionallyCreateThread(nsHostRecord* rec) MOZ_REQUIRES(mLock);
 266
 267   /**
 268    * Starts a new lookup in the background for entries that are in the grace
 269    * period with a failed connect or all cached entries are negative.
 270    */
 271   nsresult ConditionallyRefreshRecord(nsHostRecord* rec, const nsACString& host,
 272                                       const mozilla::MutexAutoLock& aLock)
 273       MOZ_REQUIRES(mLock);
 274
 275   void AddToEvictionQ(nsHostRecord* rec, const mozilla::MutexAutoLock& aLock)
 276       MOZ_REQUIRES(mLock);
 277
 278   void ThreadFunc();
 279
 280   // Resolve the host from the DNS cache.
 281   already_AddRefed<nsHostRecord> FromCache(nsHostRecord* aRec,
 282                                            const nsACString& aHost,
 283                                            uint16_t aType, nsresult& aStatus,
 284                                            const mozilla::MutexAutoLock& aLock)
 285       MOZ_REQUIRES(mLock);
 286   // Called when the host name is an IP address and has been passed.
 287   already_AddRefed<nsHostRecord> FromCachedIPLiteral(nsHostRecord* aRec);
 288   // Like the above function, but the host name is not parsed to NetAddr yet.
 289   already_AddRefed<nsHostRecord> FromIPLiteral(
 290       AddrHostRecord* aAddrRec, const mozilla::net::NetAddr& aAddr);
 291   // Called to check if we have an AF_UNSPEC entry in the cache.
 292   already_AddRefed<nsHostRecord> FromUnspecEntry(
 293       nsHostRecord* aRec, const nsACString& aHost, const nsACString& aTrrServer,
 294       const nsACString& aOriginSuffix, uint16_t aType,
 295       nsIDNSService::DNSFlags aFlags, uint16_t af, bool aPb, nsresult& aStatus)
 296       MOZ_REQUIRES(mLock);
 297
 298   enum {
 299     METHOD_HIT = 1,
 300     METHOD_RENEWAL = 2,
 301     METHOD_NEGATIVE_HIT = 3,
 302     METHOD_LITERAL = 4,
 303     METHOD_OVERFLOW = 5,
 304     METHOD_NETWORK_FIRST = 6,
 305     METHOD_NETWORK_SHARED = 7
 306   };
 307
 308   uint32_t mMaxCacheEntries = 0;
 309   uint32_t mDefaultCacheLifetime = 0;  // granularity seconds
 310   uint32_t mDefaultGracePeriod = 0;    // granularity seconds
 311   // mutable so SizeOfIncludingThis can be const
 312   mutable Mutex mLock{"nsHostResolver.mLock"};
 313   CondVar mIdleTaskCV;
 314   nsRefPtrHashtable<nsGenericHashKey<nsHostKey>, nsHostRecord> mRecordDB
 315       MOZ_GUARDED_BY(mLock);
 316   PRTime mCreationTime;
 317   mozilla::TimeDuration mLongIdleTimeout;
 318   mozilla::TimeDuration mShortIdleTimeout;
 319
 320   RefPtr<nsIThreadPool> mResolverThreads;
 321   RefPtr<mozilla::net::NetworkConnectivityService>
 322       mNCS;  // reference to a singleton
 323   mozilla::net::HostRecordQueue mQueue MOZ_GUARDED_BY(mLock);
 324   mozilla::Atomic<bool> mShutdown MOZ_GUARDED_BY(mLock){true};
 325   mozilla::Atomic<uint32_t> mNumIdleTasks MOZ_GUARDED_BY(mLock){0};
 326   mozilla::Atomic<uint32_t> mActiveTaskCount MOZ_GUARDED_BY(mLock){0};
 327   mozilla::Atomic<uint32_t> mActiveAnyThreadCount MOZ_GUARDED_BY(mLock){0};
 328
 329   // Set the expiration time stamps appropriately.
 330   void PrepareRecordExpirationAddrRecord(AddrHostRecord* rec) const;
 331
 332  public:
 333   /*
 334    * Called by the networking dashboard via the DnsService2
 335    */
 336   void GetDNSCacheEntries(nsTArray<mozilla::net::DNSCacheEntries>*);
 337 };
 338
 339 #endif  // nsHostResolver_h__