/* 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/. */ #ifndef nsHostResolver_h_ #define nsHostResolver_h_ #include "GetAddrInfo.h" #include "HostRecordQueue.h" #include "PLDHashTable.h" #include "mozilla/Atomics.h" #include "mozilla/CondVar.h" #include "mozilla/DataMutex.h" #include "mozilla/Mutex.h" #include "mozilla/StaticPrefs_network.h" #include "mozilla/TimeStamp.h" #include "mozilla/net/DNS.h" #include "mozilla/net/DNSByTypeRecord.h" #include "mozilla/net/DashboardTypes.h" #include "mozilla/net/NetworkConnectivityService.h" #include "nsHostRecord.h" #include "nsIDNSListener.h" #include "nsISupportsImpl.h" #include "nsIThreadPool.h" #include "nsRefPtrHashtable.h" #include "nsTArray.h" #include "nscore.h" #include "prnetdb.h" namespace mozilla { namespace net { class TRR; class TRRQuery; // Clamped to 1 so DequeueNextRecord can always make progress. static inline uint32_t MaxResolverThreadsAnyPriority() { return std::max(StaticPrefs::network_dns_max_any_priority_threads(), 1u); } static inline uint32_t MaxResolverThreadsHighPriority() { return StaticPrefs::network_dns_max_high_priority_threads(); } // The sum guarantees that MaxResolverThreadsHighPriority() threads are // always available for high-priority work even when all any-priority // slots are occupied by blocking lookups. static inline uint32_t MaxResolverThreads() { return MaxResolverThreadsAnyPriority() + MaxResolverThreadsHighPriority(); } } // namespace net } // namespace mozilla #define TRR_DISABLED(x) \ (((x) == nsIDNSService::MODE_NATIVEONLY) || \ ((x) == nsIDNSService::MODE_TRROFF)) #define MAX_NON_PRIORITY_REQUESTS 150 class AHostResolver { public: AHostResolver() = default; virtual ~AHostResolver() = default; NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING enum LookupStatus { LOOKUP_OK, LOOKUP_RESOLVEAGAIN, }; virtual LookupStatus CompleteLookup(nsHostRecord*, nsresult, mozilla::net::AddrInfo*, bool pb, const nsACString& aOriginsuffix, mozilla::net::TRRSkippedReason aReason, mozilla::net::TRR*) = 0; virtual LookupStatus CompleteLookupByType( nsHostRecord*, nsresult, mozilla::net::TypeRecordResultType& aResult, mozilla::net::TRRSkippedReason aReason, uint32_t aTtl, bool pb) = 0; virtual nsresult GetHostRecord(const nsACString& host, const nsACString& aTrrServer, uint16_t type, nsIDNSService::DNSFlags flags, uint16_t af, bool pb, const nsCString& originSuffix, nsHostRecord** result) { return NS_ERROR_FAILURE; } virtual nsresult TrrLookup_unlocked(nsHostRecord*, mozilla::net::TRR* pushedTRR = nullptr) { return NS_ERROR_FAILURE; } virtual void MaybeRenewHostRecord(nsHostRecord* aRec) {} }; /** * nsHostResolver - an asynchronous host name resolver. */ class nsHostResolver : public nsISupports, public AHostResolver { using CondVar = mozilla::CondVar; using Mutex = mozilla::Mutex; public: NS_DECL_THREADSAFE_ISUPPORTS /** * creates an addref'd instance of a nsHostResolver object. */ static nsresult Create(nsHostResolver** result); /** * puts the resolver in the shutdown state, which will cause any pending * callbacks to be detached. any future calls to ResolveHost will fail. */ void Shutdown(); /** * resolve the given hostname and originAttributes asynchronously. the caller * can synthesize a synchronous host lookup using a lock and a cvar. as noted * above the callback will occur re-entrantly from an unspecified thread. the * host lookup cannot be canceled (cancelation can be layered above this by * having the callback implementation return without doing anything). */ nsresult ResolveHost(const nsACString& aHost, const nsACString& trrServer, int32_t aPort, uint16_t type, const mozilla::OriginAttributes& aOriginAttributes, nsIDNSService::DNSFlags flags, uint16_t af, nsResolveHostCallback* callback); nsHostRecord* InitRecord(const nsHostKey& key); mozilla::net::NetworkConnectivityService* GetNCS() { return mNCS; } // This is actually a singleton /** * return a resolved hard coded loopback dns record for the specified key */ already_AddRefed InitLoopbackRecord(const nsHostKey& key, nsresult* aRv); /** * return a mock HTTPS record */ already_AddRefed InitMockHTTPSRecord(const nsHostKey& key); /** * removes the specified callback from the nsHostRecord for the given * hostname, originAttributes, flags, and address family. these parameters * should correspond to the parameters passed to ResolveHost. this function * executes the callback if the callback is still pending with the given * status. */ void DetachCallback(const nsACString& hostname, const nsACString& trrServer, uint16_t type, const mozilla::OriginAttributes& aOriginAttributes, nsIDNSService::DNSFlags flags, uint16_t af, nsResolveHostCallback* callback, nsresult status); /** * Cancels an async request associated with the hostname, originAttributes, * flags, address family and listener. Cancels first callback found which * matches these criteria. These parameters should correspond to the * parameters passed to ResolveHost. If this is the last callback associated * with the host record, it is removed from any request queues it might be on. */ void CancelAsyncRequest(const nsACString& host, const nsACString& trrServer, uint16_t type, const mozilla::OriginAttributes& aOriginAttributes, nsIDNSService::DNSFlags flags, uint16_t af, nsIDNSListener* aListener, nsresult status); size_t SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const; /** * Flush the DNS cache. */ void FlushCache(bool aTrrToo, bool aFlushEvictionQueue = false); LookupStatus CompleteLookup(nsHostRecord*, nsresult, mozilla::net::AddrInfo*, bool pb, const nsACString& aOriginsuffix, mozilla::net::TRRSkippedReason aReason, mozilla::net::TRR* aTRRRequest) override; LookupStatus CompleteLookupByType(nsHostRecord*, nsresult, mozilla::net::TypeRecordResultType& aResult, mozilla::net::TRRSkippedReason aReason, uint32_t aTtl, bool pb) override; nsresult GetHostRecord(const nsACString& host, const nsACString& trrServer, uint16_t type, nsIDNSService::DNSFlags flags, uint16_t af, bool pb, const nsCString& originSuffix, nsHostRecord** result) override; nsresult TrrLookup_unlocked(nsHostRecord*, mozilla::net::TRR* pushedTRR = nullptr) override; static nsIDNSService::ResolverMode Mode(); virtual void MaybeRenewHostRecord(nsHostRecord* aRec) override; // Records true if the TRR service is enabled for the record's effective // TRR mode. Also records the TRRSkipReason when the TRR service is not // available/enabled. bool TRRServiceEnabledForRecord(nsHostRecord* aRec) MOZ_REQUIRES(mQueue.mLock); private: explicit nsHostResolver(); virtual ~nsHostResolver(); using CallbackArray = nsTArray>; // Invoke all callbacks in aCallbacks with the given record and status. // Must be called outside any nsHostResolver lock. void FireCallbacks(const CallbackArray& aCallbacks, nsHostRecord* aRec, nsresult aStatus); // Move all callbacks from a LinkedList into a CallbackArray. static void DrainCallbacks( mozilla::LinkedList>& aSrc, CallbackArray& aDst); bool DoRetryTRR(AddrHostRecord* aAddrRec) MOZ_REQUIRES(mQueue.mLock); bool MaybeRetryTRRLookup( AddrHostRecord* aAddrRec, nsresult aFirstAttemptStatus, mozilla::net::TRRSkippedReason aFirstAttemptSkipReason, nsresult aChannelStatus) MOZ_REQUIRES(mQueue.mLock); LookupStatus CompleteLookupLocked(nsHostRecord*, nsresult&, mozilla::net::AddrInfo*, bool pb, const nsACString& aOriginsuffix, mozilla::net::TRRSkippedReason aReason, mozilla::net::TRR* aTRRRequest, CallbackArray& aCallbacks) MOZ_REQUIRES(mDBLock) MOZ_REQUIRES(mQueue.mLock); LookupStatus CompleteLookupByTypeLocked( nsHostRecord*, nsresult&, mozilla::net::TypeRecordResultType& aResult, mozilla::net::TRRSkippedReason aReason, uint32_t aTtl, bool pb, CallbackArray& aCallbacks) MOZ_REQUIRES(mDBLock) MOZ_REQUIRES(mQueue.mLock); nsresult Init(); static void ComputeEffectiveTRRMode(nsHostRecord* aRec); nsresult NativeLookup(nsHostRecord* aRec) MOZ_REQUIRES(mQueue.mLock); nsresult TrrLookup(nsHostRecord*, mozilla::net::TRR* pushedTRR = nullptr) MOZ_REQUIRES(mQueue.mLock); // Kick-off a name resolve operation, using native resolver and/or TRR nsresult NameLookup(nsHostRecord* aRec) MOZ_REQUIRES(mQueue.mLock); // Try to dequeue the next record without blocking. already_AddRefed DequeueNextRecord() MOZ_REQUIRES(mQueue.mLock); // Dispatch a ResolveHostTask if there's pending work. void MaybeDispatchResolveHostTask() MOZ_REQUIRES(mQueue.mLock); // Cancels host records in the pending queue and also // calls CompleteLookup with the NS_ERROR_ABORT result code. void ClearPendingQueue(mozilla::LinkedList>& aPendingQ); /** * Starts a new lookup in the background for cached entries that are in the * grace period or that are are negative. * * Also records telemetry for type of cache hit (HIT/NEGATIVE_HIT/RENEWAL). * Requires both mDBLock (for reading cache) and mQueue.mLock (for queueing * work). */ nsresult ConditionallyRefreshRecord(nsHostRecord* rec, const nsACString& host) MOZ_REQUIRES(mDBLock) MOZ_REQUIRES(mQueue.mLock); void OnResolveComplete(nsHostRecord* aRec) MOZ_REQUIRES(mDBLock) MOZ_REQUIRES(mQueue.mLock); void AddToEvictionQ(nsHostRecord* rec) MOZ_REQUIRES(mDBLock) MOZ_REQUIRES(mQueue.mLock); void ResolveHostTask(); // Resolve the host from the DNS cache. already_AddRefed FromCache(nsHostRecord* aRec, const nsACString& aHost, uint16_t aType, nsresult& aStatus, bool& aFromStaleCache) MOZ_REQUIRES(mDBLock) MOZ_REQUIRES(mQueue.mLock); // Called when the host name is an IP address and has been passed. already_AddRefed FromCachedIPLiteral(nsHostRecord* aRec); // Like the above function, but the host name is not parsed to NetAddr yet. already_AddRefed FromIPLiteral( AddrHostRecord* aAddrRec, const mozilla::net::NetAddr& aAddr); // Called to check if we have an AF_UNSPEC entry in the cache. already_AddRefed FromUnspecEntry( nsHostRecord* aRec, const nsACString& aHost, const nsACString& aTrrServer, const nsACString& aOriginSuffix, uint16_t aType, nsIDNSService::DNSFlags aFlags, uint16_t af, bool aPb, nsresult& aStatus, bool& aFromStaleCache) MOZ_REQUIRES(mDBLock) MOZ_REQUIRES(mQueue.mLock); bool OtherFamilyHasUsablePositiveResult(const nsHostKey& aKey, uint16_t aAf, const mozilla::TimeStamp& aNow, nsIDNSService::DNSFlags aFlags) MOZ_REQUIRES(mDBLock); enum { METHOD_HIT = 1, METHOD_RENEWAL = 2, METHOD_NEGATIVE_HIT = 3, METHOD_LITERAL = 4, METHOD_OVERFLOW = 5, METHOD_NETWORK_FIRST = 6, METHOD_NETWORK_SHARED = 7 }; // mutable so SizeOfIncludingThis can be const // Protects mRecordDB. When held together with mQueue.mLock, always acquire // mDBLock first. mutable Mutex mDBLock{"nsHostResolver.mDBLock"}; mozilla::net::HostRecordQueue mQueue; nsRefPtrHashtable, nsHostRecord> mRecordDB MOZ_GUARDED_BY(mDBLock); PRTime mCreationTime; RefPtr mResolverThreads; RefPtr mNCS; // reference to a singleton // TODO: mShutdown is set under mQueue.mLock but read without it in a // telemetry guard. Could be made non-atomic + MOZ_GUARDED_BY if that // guard is removed. mozilla::Atomic mShutdown{true}; uint32_t mActiveAnyThreadCount MOZ_GUARDED_BY(mQueue.mLock) = 0; // Set the expiration time stamps appropriately. void PrepareRecordExpirationAddrRecord(AddrHostRecord* rec) const MOZ_REQUIRES(rec->addr_info_lock); public: /* * Called by the networking dashboard via the DnsService2 */ void GetDNSCacheEntries(nsTArray*); static bool IsNativeHTTPSEnabled(); }; #endif // nsHostResolver_h_