EarlyHintPreloader.h

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/* 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 mozilla_net_EarlyHintPreloader_h

#define mozilla_net_EarlyHintPreloader_h

#include "mozilla/dom/ipc/IdType.h"

#include "mozilla/Maybe.h"

#include "mozilla/PreloadHashKey.h"

#include "NeckoCommon.h"

#include "mozilla/net/NeckoChannelParams.h"

#include "nsHashtablesFwd.h"

#include "nsIChannelEventSink.h"

#include "nsIInterfaceRequestor.h"

#include "nsIMultiPartChannel.h"

#include "nsIRedirectResultListener.h"

#include "nsIStreamListener.h"

#include "nsITimer.h"

#include "nsNetUtil.h"

class nsAttrValue;

class nsICookieJarSettings;

class nsILoadContext;

class nsIPrincipal;

class nsIReferrerInfo;

namespace mozilla::dom {

class CanonicalBrowsingContext;

namespace mozilla::net {

class EarlyHintPreloader;

class EarlyHintConnectArgs;

class ParentChannelListener;

struct LinkHeader;

// class keeping track of all ongoing early hints

class OngoingEarlyHints final {

 public:

  NS_INLINE_DECL_REFCOUNTING(OngoingEarlyHints)

  OngoingEarlyHints() = default;

  // returns whether a preload with that key already existed

  bool Contains(const PreloadHashKey& aKey);

  bool Add(const PreloadHashKey& aKey, RefPtr<EarlyHintPreloader> aPreloader);

  void CancelAll(const nsACString& aReason);

  // registers all channels and returns the ids

  void RegisterLinksAndGetConnectArgs(

      dom::ContentParentId aCpId, nsTArray<EarlyHintConnectArgs>& aOutLinks);

 private:

  ~OngoingEarlyHints() = default;

  // We need to do two things requiring two separate variables to keep track of

  // preloads:

  //  - deduplicate Link headers when starting preloads, therefore we store them

  //    hashset with PreloadHashKey to look up whether we started the preload

  //    already

  //  - pass link headers in order they were received when passing all started

  //    preloads to the content process, therefore we store them in a nsTArray

  nsTHashSet<PreloadHashKey> mStartedPreloads;

  nsTArray<RefPtr<EarlyHintPreloader>> mPreloaders;

};

class EarlyHintPreloader final : public nsIStreamListener,

                                 public nsIChannelEventSink,

                                 public nsIRedirectResultListener,

                                 public nsIInterfaceRequestor,

                                 public nsIMultiPartChannelListener,

                                 public nsINamed,

                                 public nsITimerCallback {

 public:

  NS_DECL_ISUPPORTS

  NS_DECL_NSIREQUESTOBSERVER

  NS_DECL_NSISTREAMLISTENER

  NS_DECL_NSICHANNELEVENTSINK

  NS_DECL_NSIREDIRECTRESULTLISTENER

  NS_DECL_NSIINTERFACEREQUESTOR

  NS_DECL_NSIMULTIPARTCHANNELLISTENER

  // required by NS_DECL_NSITIMERCALLBACK

  NS_DECL_NSINAMED

  NS_DECL_NSITIMERCALLBACK

 public:

  // Create and insert a preload into OngoingEarlyHints if the same preload

  // wasn't already issued and the LinkHeader can be parsed correctly.

  static void MaybeCreateAndInsertPreload(

      OngoingEarlyHints* aOngoingEarlyHints, const LinkHeader& aHeader,

      nsIURI* aBaseURI, nsIPrincipal* aPrincipal,

      nsICookieJarSettings* aCookieJarSettings,

      const nsACString& aReferrerPolicy, const nsACString& aCSPHeader,

      uint64_t aBrowsingContextID,

      dom::CanonicalBrowsingContext* aLoadingBrowsingContext,

      bool aIsModulepreload);

  // register Channel to EarlyHintRegistrar. Returns true and sets connect args

  // if successful

  bool Register(dom::ContentParentId aCpId, EarlyHintConnectArgs& aOut);

  // Allows EarlyHintRegistrar to check if the correct content process accesses

  // this preload. Preventing compromised content processes to access Early Hint

  // preloads from other origins

  bool IsFromContentParent(dom::ContentParentId aCpId) const;

  // Should be called by the preloader service when the preload is not

  // needed after all, because the final response returns a non-2xx status

  // code. If aDeleteEntry is false, the calling function MUST make sure that

  // the EarlyHintPreloader is not in the EarlyHintRegistrar anymore. Because

  // after this function, the EarlyHintPreloader can't connect back to the

  // parent anymore.

  nsresult CancelChannel(nsresult aStatus, const nsACString& aReason,

                         bool aDeleteEntry);

  void OnParentReady(nsIParentChannel* aParent);

 private:

  void SetParentChannel();

  void InvokeStreamListenerFunctions();

  EarlyHintPreloader();

  ~EarlyHintPreloader();

  static Maybe<PreloadHashKey> GenerateHashKey(ASDestination aAs, nsIURI* aURI,

                                               nsIPrincipal* aPrincipal,

                                               CORSMode corsMode,

                                               bool aIsModulepreload);

  static nsSecurityFlags ComputeSecurityFlags(CORSMode aCORSMode,

                                              ASDestination aAs);

  // call to start the preload

  nsresult OpenChannel(nsIURI* aURI, nsIPrincipal* aPrincipal,

                       nsSecurityFlags aSecurityFlags,

                       nsContentPolicyType aContentPolicyType,

                       nsIReferrerInfo* aReferrerInfo,

                       nsICookieJarSettings* aCookieJarSettings,

                       uint64_t aBrowsingContextID);

  void PriorizeAsPreload();

  void SetLinkHeader(const LinkHeader& aLinkHeader);

  static void CollectResourcesTypeTelemetry(ASDestination aASDestination);

  nsCOMPtr<nsIChannel> mChannel;

  nsCOMPtr<nsIChannel> mRedirectChannel;

  dom::ContentParentId mCpId;

  EarlyHintConnectArgs mConnectArgs;

  // Copy behavior from DocumentLoadListener.h:

  // https://searchfox.org/mozilla-central/rev/c0bed29d643393af6ebe77aa31455f283f169202/netwerk/ipc/DocumentLoadListener.h#487-512

  // The set of nsIStreamListener functions that got called on this

  // listener, so that we can replay them onto the replacement channel's

  // listener. This should generally only be OnStartRequest, since we

  // Suspend() the channel at that point, but it can fail sometimes

  // so we have to support holding a list.

  nsTArray<StreamListenerFunction> mStreamListenerFunctions;

  // Set to true once OnStartRequest is called

  bool mOnStartRequestCalled = false;

  // Set to true if we suspended mChannel in the OnStartRequest call

  bool mSuspended = false;

  nsCOMPtr<nsIParentChannel> mParent;

  // Set to true after we've received the last OnStopRequest, and shouldn't

  // setup a reference from the ParentChannelListener to the replacement

  // channel.

  bool mIsFinished = false;

  RefPtr<ParentChannelListener> mParentListener;

  nsCOMPtr<nsITimer> mTimer;

  // Hold the load context to provide data to web extension and anti tracking.

  // See Bug 1836289 and Bug 1875268

  nsCOMPtr<nsILoadContext> mLoadContext;

 private:

  // IMPORTANT: when adding new values, always add them to the end, otherwise

  // it will mess up telemetry.

  enum EHPreloaderState : uint32_t {

    ePreloaderCreated = 0,

    ePreloaderOpened,

    ePreloaderUsed,

    ePreloaderCancelled,

    ePreloaderTimeout,

};

  EHPreloaderState mState = ePreloaderCreated;

  void SetState(EHPreloaderState aState) { mState = aState; }

};

inline nsISupports* ToSupports(EarlyHintPreloader* aObj) {

  return static_cast<nsIInterfaceRequestor*>(aObj);

}  // namespace mozilla::net

#endif  // mozilla_net_EarlyHintPreloader_h