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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// A server side dispatcher which dispatches a given client's data to their
// stream.
#include <memory>
#include <unordered_map>
#include <vector>
#include "base/macros.h"
#include "net/base/ip_endpoint.h"
#include "net/base/linked_hash_map.h"
#include "net/quic/crypto/quic_compressed_certs_cache.h"
#include "net/quic/crypto/quic_random.h"
#include "net/quic/quic_blocked_writer_interface.h"
#include "net/quic/quic_connection.h"
#include "net/quic/quic_protocol.h"
#include "net/quic/quic_server_session_base.h"
#include "net/tools/quic/quic_process_packet_interface.h"
#include "net/tools/quic/quic_time_wait_list_manager.h"
namespace net {
class QuicConfig;
class QuicCryptoServerConfig;
class QuicServerSessionBase;
namespace test {
class QuicDispatcherPeer;
} // namespace test
class QuicDispatcher : public QuicServerSessionBase::Visitor,
public ProcessPacketInterface,
public QuicBlockedWriterInterface,
public QuicFramerVisitorInterface {
// Ideally we'd have a linked_hash_set: the boolean is unused.
typedef linked_hash_map<QuicBlockedWriterInterface*,
QuicDispatcher(const QuicConfig& config,
const QuicCryptoServerConfig* crypto_config,
const QuicVersionVector& supported_versions,
std::unique_ptr<QuicConnectionHelperInterface> helper,
std::unique_ptr<QuicServerSessionBase::Helper> session_helper,
std::unique_ptr<QuicAlarmFactory> alarm_factory);
~QuicDispatcher() override;
// Takes ownership of |writer|.
void InitializeWithWriter(QuicPacketWriter* writer);
// Process the incoming packet by creating a new session, passing it to
// an existing session, or passing it to the time wait list.
void ProcessPacket(const IPEndPoint& server_address,
const IPEndPoint& client_address,
const QuicReceivedPacket& packet) override;
// Called when the socket becomes writable to allow queued writes to happen.
void OnCanWrite() override;
// Returns true if there's anything in the blocked writer list.
virtual bool HasPendingWrites() const;
// Sends ConnectionClose frames to all connected clients.
void Shutdown();
// QuicServerSessionBase::Visitor interface implementation:
// Ensure that the closed connection is cleaned up asynchronously.
void OnConnectionClosed(QuicConnectionId connection_id,
QuicErrorCode error,
const std::string& error_details) override;
// Queues the blocked writer for later resumption.
void OnWriteBlocked(QuicBlockedWriterInterface* blocked_writer) override;
// Called whenever the time wait list manager adds a new connection to the
// time-wait list.
void OnConnectionAddedToTimeWaitList(QuicConnectionId connection_id) override;
typedef std::unordered_map<QuicConnectionId, QuicServerSessionBase*>
const SessionMap& session_map() const { return session_map_; }
// Deletes all sessions on the closed session list and clears the list.
virtual void DeleteSessions();
// The largest packet number we expect to receive with a connection
// ID for a connection that is not established yet. The current design will
// send a handshake and then up to 50 or so data packets, and then it may
// resend the handshake packet up to 10 times. (Retransmitted packets are
// sent with unique packet numbers.)
static const QuicPacketNumber kMaxReasonableInitialPacketNumber = 100;
static_assert(kMaxReasonableInitialPacketNumber >=
kInitialCongestionWindow + 10,
"kMaxReasonableInitialPacketNumber is unreasonably small "
"relative to kInitialCongestionWindow.");
// QuicFramerVisitorInterface implementation. Not expected to be called
// outside of this class.
void OnPacket() override;
// Called when the public header has been parsed.
bool OnUnauthenticatedPublicHeader(
const QuicPacketPublicHeader& header) override;
// Called when the private header has been parsed of a data packet that is
// destined for the time wait manager.
bool OnUnauthenticatedHeader(const QuicPacketHeader& header) override;
void OnError(QuicFramer* framer) override;
bool OnProtocolVersionMismatch(QuicVersion received_version) override;
// The following methods should never get called because
// OnUnauthenticatedPublicHeader() or OnUnauthenticatedHeader() (whichever
// was called last), will return false and prevent a subsequent invocation
// of these methods. Thus, the payload of the packet is never processed in
// the dispatcher.
void OnPublicResetPacket(const QuicPublicResetPacket& packet) override;
void OnVersionNegotiationPacket(
const QuicVersionNegotiationPacket& packet) override;
void OnDecryptedPacket(EncryptionLevel level) override;
bool OnPacketHeader(const QuicPacketHeader& header) override;
bool OnStreamFrame(const QuicStreamFrame& frame) override;
bool OnAckFrame(const QuicAckFrame& frame) override;
bool OnStopWaitingFrame(const QuicStopWaitingFrame& frame) override;
bool OnPaddingFrame(const QuicPaddingFrame& frame) override;
bool OnPingFrame(const QuicPingFrame& frame) override;
bool OnRstStreamFrame(const QuicRstStreamFrame& frame) override;
bool OnConnectionCloseFrame(const QuicConnectionCloseFrame& frame) override;
bool OnGoAwayFrame(const QuicGoAwayFrame& frame) override;
bool OnWindowUpdateFrame(const QuicWindowUpdateFrame& frame) override;
bool OnBlockedFrame(const QuicBlockedFrame& frame) override;
bool OnPathCloseFrame(const QuicPathCloseFrame& frame) override;
void OnPacketComplete() override;
virtual QuicServerSessionBase* CreateQuicSession(
QuicConnectionId connection_id,
const IPEndPoint& client_address);
// Called when a connection is rejected statelessly.
virtual void OnConnectionRejectedStatelessly();
// Called when a connection is closed statelessly.
virtual void OnConnectionClosedStatelessly(QuicErrorCode error);
// Returns true if cheap stateless rejection should be attempted.
virtual bool ShouldAttemptCheapStatelessRejection();
// Values to be returned by ValidityChecks() to indicate what should be done
// with a packet. Fates with greater values are considered to be higher
// priority, in that if one validity check indicates a lower-valued fate and
// another validity check indicates a higher-valued fate, the higher-valued
// fate should be obeyed.
enum QuicPacketFate {
// Process the packet normally, which is usually to establish a connection.
// Put the connection ID into time-wait state and send a public reset.
// Drop the packet (ignore and give no response).
// This method is called by OnUnauthenticatedHeader on packets not associated
// with a known connection ID. It applies validity checks and returns a
// QuicPacketFate to tell what should be done with the packet.
virtual QuicPacketFate ValidityChecks(const QuicPacketHeader& header);
// Create and return the time wait list manager for this dispatcher, which
// will be owned by the dispatcher as time_wait_list_manager_
virtual QuicTimeWaitListManager* CreateQuicTimeWaitListManager();
QuicTimeWaitListManager* time_wait_list_manager() {
return time_wait_list_manager_.get();
const QuicVersionVector& GetSupportedVersions();
const IPEndPoint& current_server_address() { return current_server_address_; }
const IPEndPoint& current_client_address() { return current_client_address_; }
const QuicReceivedPacket& current_packet() { return *current_packet_; }
const QuicConfig& config() const { return config_; }
const QuicCryptoServerConfig* crypto_config() const { return crypto_config_; }
QuicCompressedCertsCache* compressed_certs_cache() {
return &compressed_certs_cache_;
QuicFramer* framer() { return &framer_; }
QuicConnectionHelperInterface* helper() { return helper_.get(); }
QuicServerSessionBase::Helper* session_helper() {
return session_helper_.get();
QuicAlarmFactory* alarm_factory() { return alarm_factory_.get(); }
QuicPacketWriter* writer() { return writer_.get(); }
// Creates per-connection packet writers out of the QuicDispatcher's shared
// QuicPacketWriter. The per-connection writers' IsWriteBlocked() state must
// always be the same as the shared writer's IsWriteBlocked(), or else the
// QuicDispatcher::OnCanWrite logic will not work. (This will hopefully be
// cleaned up for bug 16950226.)
virtual QuicPacketWriter* CreatePerConnectionWriter();
// Returns true if a session should be created for a connection with an
// unknown version identified by |version_tag|.
virtual bool ShouldCreateSessionForUnknownVersion(QuicTag version_tag);
void SetLastError(QuicErrorCode error);
// Called when the public header has been parsed and the session has been
// looked up, and the session was not found in the active list of sessions.
// Returns false if processing should stop after this call.
virtual bool OnUnauthenticatedUnknownPublicHeader(
const QuicPacketPublicHeader& header);
friend class net::test::QuicDispatcherPeer;
// Removes the session from the session map and write blocked list, and adds
// the ConnectionId to the time-wait list. If |session_closed_statelessly| is
// true, any future packets for the ConnectionId will be black-holed.
void CleanUpSession(SessionMap::iterator it, bool session_closed_statelessly);
bool HandlePacketForTimeWait(const QuicPacketPublicHeader& header);
// Attempts to reject the connection statelessly, if stateless rejects are
// possible and if the current packet contains a CHLO message.
// Returns a fate which describes what subsequent processing should be
// performed on the packets, like ValidityChecks.
QuicPacketFate MaybeRejectStatelessly(QuicConnectionId connection_id,
const QuicPacketHeader& header);
const QuicConfig& config_;
const QuicCryptoServerConfig* crypto_config_;
// The cache for most recently compressed certs.
QuicCompressedCertsCache compressed_certs_cache_;
// The list of connections waiting to write.
WriteBlockedList write_blocked_list_;
SessionMap session_map_;
// Entity that manages connection_ids in time wait state.
std::unique_ptr<QuicTimeWaitListManager> time_wait_list_manager_;
// The list of closed but not-yet-deleted sessions.
std::vector<QuicServerSessionBase*> closed_session_list_;
// The helper used for all connections.
std::unique_ptr<QuicConnectionHelperInterface> helper_;
// The helper used for all sessions.
std::unique_ptr<QuicServerSessionBase::Helper> session_helper_;
// Creates alarms.
std::unique_ptr<QuicAlarmFactory> alarm_factory_;
// An alarm which deletes closed sessions.
std::unique_ptr<QuicAlarm> delete_sessions_alarm_;
// The writer to write to the socket with.
std::unique_ptr<QuicPacketWriter> writer_;
// This vector contains QUIC versions which we currently support.
// This should be ordered such that the highest supported version is the first
// element, with subsequent elements in descending order (versions can be
// skipped as necessary).
QuicVersionVector supported_versions_;
// FLAGS_quic_disable_pre_30
bool disable_quic_pre_30_;
// The list of versions that may be supported by this dispatcher.
// |supported_versions| is derived from this list and |disable_quic_pre_30_|.
const QuicVersionVector allowed_supported_versions_;
// Information about the packet currently being handled.
IPEndPoint current_client_address_;
IPEndPoint current_server_address_;
const QuicReceivedPacket* current_packet_;
QuicConnectionId current_connection_id_;
QuicFramer framer_;
// The last error set by SetLastError(), which is called by
// framer_visitor_->OnError().
QuicErrorCode last_error_;
} // namespace net