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#pragma once #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS #if HAVE_OPENSSL && NODE_OPENSSL_HAS_QUIC #include <aliased_struct.h> #include <async_wrap.h> #include <env.h> #include <node_sockaddr.h> #include <uv.h> #include <v8.h> #include <algorithm> #include <optional> #include "bindingdata.h" #include "packet.h" #include "session.h" #include "sessionticket.h" #include "tokens.h" namespace node { namespace quic { // An Endpoint encapsulates the UDP local port binding and is responsible for // sending and receiving QUIC packets. A single endpoint can act as both a QUIC // client and server simultaneously. class Endpoint final : public AsyncWrap, public Packet::Listener { public: static constexpr uint64_t DEFAULT_MAX_CONNECTIONS = std::min<uint64_t>(kMaxSizeT, static_cast<uint64_t>(kMaxSafeJsInteger)); static constexpr uint64_t DEFAULT_MAX_CONNECTIONS_PER_HOST = 100; static constexpr uint64_t DEFAULT_MAX_SOCKETADDRESS_LRU_SIZE = (DEFAULT_MAX_CONNECTIONS_PER_HOST * 10); static constexpr uint64_t DEFAULT_MAX_STATELESS_RESETS = 10; static constexpr uint64_t DEFAULT_MAX_RETRY_LIMIT = 10; static constexpr auto QUIC_CC_ALGO_RENO = NGTCP2_CC_ALGO_RENO; static constexpr auto QUIC_CC_ALGO_CUBIC = NGTCP2_CC_ALGO_CUBIC; static constexpr auto QUIC_CC_ALGO_BBR = NGTCP2_CC_ALGO_BBR; // Endpoint configuration options struct Options final : public MemoryRetainer { // The local socket address to which the UDP port will be bound. The port // may be 0 to have Node.js select an available port. IPv6 or IPv4 addresses // may be used. When using IPv6, dual mode will be supported by default. std::shared_ptr<SocketAddress> local_address; // Retry tokens issued by the Endpoint are time-limited. By default, retry // tokens expire after DEFAULT_RETRYTOKEN_EXPIRATION *seconds*. This is an // arbitrary choice that is not mandated by the QUIC specification; so we // can choose any value that makes sense here. Retry tokens are sent to the // client, which echoes them back to the server in a subsequent set of // packets, which means the expiration must be set high enough to allow a // reasonable round-trip time for the session TLS handshake to complete. uint64_t retry_token_expiration = RetryToken::QUIC_DEFAULT_RETRYTOKEN_EXPIRATION / NGTCP2_SECONDS; // Tokens issued using NEW_TOKEN are time-limited. By default, tokens expire // after DEFAULT_TOKEN_EXPIRATION *seconds*. uint64_t token_expiration = RegularToken::QUIC_DEFAULT_REGULARTOKEN_EXPIRATION / NGTCP2_SECONDS; // Each Endpoint places limits on the number of concurrent connections from // a single host, and the total number of concurrent connections allowed as // a whole. These are set to fairly modest, and arbitrary defaults. We can // set these to whatever we'd like. uint64_t max_connections_per_host = DEFAULT_MAX_CONNECTIONS_PER_HOST; uint64_t max_connections_total = DEFAULT_MAX_CONNECTIONS; // A stateless reset in QUIC is a discrete mechanism that one endpoint can // use to communicate to a peer that it has lost whatever state it // previously held about a session. Because generating a stateless reset // consumes resources (even very modestly), they can be a DOS vector in // which a malicious peer intentionally sends a large number of stateless // reset eliciting packets. To protect against that risk, we limit the // number of stateless resets that may be generated for a given remote host // within a window of time. This is not mandated by QUIC, and the limit is // arbitrary. We can set it to whatever we'd like. uint64_t max_stateless_resets = DEFAULT_MAX_STATELESS_RESETS; // For tracking the number of connections per host, the number of stateless // resets that have been sent, and tracking the path verification status of // a remote host, we maintain an LRU cache of the most recently seen hosts. // The address_lru_size parameter determines the size of that cache. The // default is set modestly at 10 times the default max connections per host. uint64_t address_lru_size = DEFAULT_MAX_SOCKETADDRESS_LRU_SIZE; // Similar to stateless resets, we enforce a limit on the number of retry // packets that can be generated and sent for a remote host. Generating // retry packets consumes a modest amount of resources and it's fairly // trivial for a malcious peer to trigger generation of a large number of // retries, so limiting them helps prevent a DOS vector. uint64_t max_retries = DEFAULT_MAX_RETRY_LIMIT; // The max_payload_size is the maximum size of a serialized QUIC packet. It // should always be set small enough to fit within a single MTU without // fragmentation. The default is set by the QUIC specification at 1200. This // value should not be changed unless you know for sure that the entire path // supports a given MTU without fragmenting at any point in the path. uint64_t max_payload_size = kDefaultMaxPacketLength; // The unacknowledged_packet_threshold is the maximum number of // unacknowledged packets that an ngtcp2 session will accumulate before // sending an acknowledgement. Setting this to 0 uses the ngtcp2 defaults, // which is what most will want. The value can be changed to fine tune some // of the performance characteristics of the session. This should only be // changed if you have a really good reason for doing so. uint64_t unacknowledged_packet_threshold = 0; // The amount of time (in milliseconds) that the endpoint will wait for the // completion of the tls handshake. uint64_t handshake_timeout = UINT64_MAX; uint64_t max_stream_window = 0; uint64_t max_window = 0; bool no_udp_payload_size_shaping = true; // The validate_address parameter instructs the Endpoint to perform explicit // address validation using retry tokens. This is strongly recommended and // should only be disabled in trusted, closed environments as a performance // optimization. bool validate_address = true; // The stateless reset mechanism can be disabled. This should rarely ever be // needed, and should only ever be done in trusted, closed environments as a // performance optimization. bool disable_stateless_reset = false; #ifdef DEBUG // The rx_loss and tx_loss parameters are debugging tools that allow the // Endpoint to simulate random packet loss. The value for each parameter is // a value between 0.0 and 1.0 indicating a probability of packet loss. Each // time a packet is sent or received, the packet loss bit is calculated and // if true, the packet is silently dropped. This should only ever be used // for testing and debugging. There is never a reason why rx_loss and // tx_loss should ever be used in a production system. double rx_loss = 0.0; double tx_loss = 0.0; #endif // DEBUG // There are several common congestion control algorithms that ngtcp2 uses // to determine how it manages the flow control window: RENO, CUBIC, and // BBR. The details of how each works is not relevant here. The choice of // which to use by default is arbitrary and we can choose whichever we'd // like. Additional performance profiling will be needed to determine which // is the better of the two for our needs. ngtcp2_cc_algo cc_algorithm = NGTCP2_CC_ALGO_CUBIC; // By default, when the endpoint is created, it will generate a // reset_token_secret at random. This is a secret used in generating // stateless reset tokens. In order for stateless reset to be effective, // however, it is necessary to use a deterministic secret that persists // across ngtcp2 endpoints and sessions. This means that the endpoint // configuration really should have a reset token secret passed in. TokenSecret reset_token_secret; // The secret used for generating new regular tokens. TokenSecret token_secret; // When the local_address specifies an IPv6 local address to bind to, the // ipv6_only parameter determines whether dual stack mode (supporting both // IPv6 and IPv4) transparently is supported. This sets the UV_UDP_IPV6ONLY // flag on the underlying uv_udp_t. bool ipv6_only = false; uint32_t udp_receive_buffer_size = 0; uint32_t udp_send_buffer_size = 0; // The UDP TTL configuration is the number of network hops a packet will be // forwarded through. The default is 64. The value is in the range 1 to 255. // Setting to 0 uses the default. uint8_t udp_ttl = 0; void MemoryInfo(MemoryTracker* tracker) const override; SET_MEMORY_INFO_NAME(Endpoint::Config) SET_SELF_SIZE(Options) static v8::Maybe<Options> From(Environment* env, v8::Local<v8::Value> value); std::string ToString() const; }; bool HasInstance(Environment* env, v8::Local<v8::Value> value); static v8::Local<v8::FunctionTemplate> GetConstructorTemplate( Environment* env); static void InitPerIsolate(IsolateData* data, v8::Local<v8::ObjectTemplate> target); static void InitPerContext(Realm* realm, v8::Local<v8::Object> target); static void RegisterExternalReferences(ExternalReferenceRegistry* registry); Endpoint(Environment* env, v8::Local<v8::Object> object, const Endpoint::Options& options); inline const Options& options() const { return options_; } // While the busy flag is set, the Endpoint will reject all initial packets // with a SERVER_BUSY response. This allows us to build a circuit breaker // directly into the implementation, explicitly signaling that the server is // blocked when activity is too high. void MarkAsBusy(bool on = true); // Use the endpoint's token secret to generate a new token. RegularToken GenerateNewToken(uint32_t version, const SocketAddress& remote_address); // Use the endpoint's reset token secret to generate a new stateless reset. StatelessResetToken GenerateNewStatelessResetToken(uint8_t* token, const CID& cid) const; void AddSession(const CID& cid, BaseObjectPtr<Session> session); void RemoveSession(const CID& cid); BaseObjectPtr<Session> FindSession(const CID& cid); // A single session may be associated with multiple CIDs. // AssociateCID registers the mapping both in the Endpoint and the inner // Endpoint. void AssociateCID(const CID& cid, const CID& scid); void DisassociateCID(const CID& cid); // Associates a given stateless reset token with the session. This allows // stateless reset tokens to be recognized and dispatched to the proper // Endpoint and Session for processing. void AssociateStatelessResetToken(const StatelessResetToken& token, Session* session); void DisassociateStatelessResetToken(const StatelessResetToken& token); void Send(Packet* packet); // Generates and sends a retry packet. This is terminal for the connection. // Retry packets are used to force explicit path validation by issuing a token // to the peer that it must thereafter include in all subsequent initial // packets. Upon receiving a retry packet, the peer must termination it's // initial attempt to establish a connection and start a new attempt. // // Retry packets will only ever be generated by QUIC servers, and only if the // QuicSocket is configured for explicit path validation. There is no way for // a client to force a retry packet to be created. However, once a client // determines that explicit path validation is enabled, it could attempt to // DOS by sending a large number of malicious initial packets to intentionally // ellicit retry packets (It can do so by intentionally sending initial // packets that ignore the retry token). To help mitigate that risk, we limit // the number of retries we send to a given remote endpoint. void SendRetry(const PathDescriptor& options); // Sends a version negotiation packet. This is terminal for the connection and // is sent only when a QUIC packet is received for an unsupported QUIC // version. It is possible that a malicious packet triggered this so we need // to be careful not to commit too many resources. void SendVersionNegotiation(const PathDescriptor& options); // Possibly generates and sends a stateless reset packet. This is terminal for // the connection. It is possible that a malicious packet triggered this so we // need to be careful not to commit too many resources. bool SendStatelessReset(const PathDescriptor& options, size_t source_len); // Shutdown a connection prematurely, before a Session is created. This should // only be called at the start of a session before the crypto keys have been // established. void SendImmediateConnectionClose(const PathDescriptor& options, QuicError error); // Listen for connections (act as a server). void Listen(const Session::Options& options); // Create a new client-side Session. BaseObjectPtr<Session> Connect( const SocketAddress& remote_address, const Session::Options& options, std::optional<SessionTicket> sessionTicket = std::nullopt); // Returns the local address only if the endpoint has been bound. Before // the endpoint is bound, or after it is closed, this will abort due to // a failed check so it is important to check `is_closed()` before calling. SocketAddress local_address() const; void MemoryInfo(MemoryTracker* tracker) const override; SET_MEMORY_INFO_NAME(Endpoint) SET_SELF_SIZE(Endpoint) struct Stats; struct State; private: class UDP final : public MemoryRetainer { public: explicit UDP(Endpoint* endpoint); ~UDP() override; int Bind(const Endpoint::Options& config); int Start(); void Stop(); void Close(); int Send(Packet* packet); // Returns the local UDP socket address to which we are bound, // or fail with an assert if we are not bound. SocketAddress local_address() const; bool is_bound() const; bool is_closed() const; bool is_closed_or_closing() const; operator bool() const; void Ref(); void Unref(); void MemoryInfo(node::MemoryTracker* tracker) const override; SET_MEMORY_INFO_NAME(Endpoint::UDP) SET_SELF_SIZE(UDP) private: class Impl; BaseObjectWeakPtr<Impl> impl_; bool is_bound_ = false; bool is_started_ = false; bool is_closed_ = false; }; bool is_closed() const; bool is_closing() const; bool is_listening() const; bool Start(); // Destroy the endpoint if... // * There are no sessions, // * There are no sent packets with pending done callbacks, and // * We're not listening for new initial packets. void MaybeDestroy(); // Specifies the general reason the endpoint is being destroyed. enum class CloseContext { CLOSE, BIND_FAILURE, START_FAILURE, RECEIVE_FAILURE, SEND_FAILURE, LISTEN_FAILURE, }; void Destroy(CloseContext context = CloseContext::CLOSE, int status = 0); // A graceful close will destroy the endpoint once all existing sessions // have ended normally. Creating new sessions (inbound or outbound) will // be prevented. void CloseGracefully(); void Release(); void PacketDone(int status) override; void EmitNewSession(const BaseObjectPtr<Session>& session); void EmitClose(CloseContext context, int status); void IncrementSocketAddressCounter(const SocketAddress& address); void DecrementSocketAddressCounter(const SocketAddress& address); // JavaScript API // Create a new Endpoint. // @param Endpoint::Options options - Options to configure the Endpoint. static void New(const v8::FunctionCallbackInfo<v8::Value>& args); // Methods on the Endpoint instance: // Create a new client Session on this endpoint. // @param node::SocketAddress local_address - The local address to bind to. // @param Session::Options options - Options to configure the Session. // @param v8::ArrayBufferView session_ticket - The session ticket to use for // the Session. // @param v8::ArrayBufferView remote_transport_params - The remote transport // params. static void DoConnect(const v8::FunctionCallbackInfo<v8::Value>& args); // Start listening as a QUIC server // @param Session::Options options - Options to configure the Session. static void DoListen(const v8::FunctionCallbackInfo<v8::Value>& args); // Mark the Endpoint as busy, temporarily pausing handling of new initial // packets. // @param bool on - If true, mark the Endpoint as busy. static void MarkBusy(const v8::FunctionCallbackInfo<v8::Value>& args); static void FastMarkBusy(v8::Local<v8::Object> receiver, bool on); // DoCloseGracefully is the signal that endpoint should close. Any packets // that are already in the queue or in flight will be allowed to finish, but // the EndpoingWrap will be otherwise no longer able to receive or send // packets. static void DoCloseGracefully( const v8::FunctionCallbackInfo<v8::Value>& args); // Get the local address of the Endpoint. // @return node::SocketAddress - The local address of the Endpoint. static void LocalAddress(const v8::FunctionCallbackInfo<v8::Value>& args); // Ref() causes a listening Endpoint to keep the event loop active. static void Ref(const v8::FunctionCallbackInfo<v8::Value>& args); static void FastRef(v8::Local<v8::Object> receiver, bool on); void Receive(const uv_buf_t& buf, const SocketAddress& from); AliasedStruct<Stats> stats_; AliasedStruct<State> state_; const Options options_; UDP udp_; // Set if/when the endpoint is configured to listen. std::optional<Session::Options> server_options_{}; // A Session is generally identified by one or more CIDs. We use two // maps for this rather than one to avoid creating a whole bunch of // BaseObjectPtr references. The primary map (sessions_) just maps // the original CID to the Session, the second map (dcid_to_scid_) // maps the additional CIDs to the primary. CID::Map<BaseObjectPtr<Session>> sessions_; CID::Map<CID> dcid_to_scid_; StatelessResetToken::Map<Session*> token_map_; struct SocketAddressInfoTraits final { struct Type final { size_t active_connections; size_t reset_count; size_t retry_count; uint64_t timestamp; bool validated; }; static bool CheckExpired(const SocketAddress& address, const Type& type); static void Touch(const SocketAddress& address, Type* type); }; SocketAddressLRU<SocketAddressInfoTraits> addrLRU_; CloseContext close_context_ = CloseContext::CLOSE; int close_status_ = 0; friend class UDP; friend class Packet; friend class Session; }; } // namespace quic } // namespace node #endif // HAVE_OPENSSL && NODE_OPENSSL_HAS_QUIC #endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS