package protocol import "time" // DesiredReceiveBufferSize is the kernel UDP receive buffer size that we'd like to use. const DesiredReceiveBufferSize = (1 << 20) * 2 // 2 MB // InitialPacketSizeIPv4 is the maximum packet size that we use for sending IPv4 packets. const InitialPacketSizeIPv4 = 1252 // InitialPacketSizeIPv6 is the maximum packet size that we use for sending IPv6 packets. const InitialPacketSizeIPv6 = 1232 // MaxCongestionWindowPackets is the maximum congestion window in packet. const MaxCongestionWindowPackets = 10000 // MaxUndecryptablePackets limits the number of undecryptable packets that are queued in the connection. const MaxUndecryptablePackets = 32 // ConnectionFlowControlMultiplier determines how much larger the connection flow control windows needs to be relative to any stream's flow control window // This is the value that Chromium is using const ConnectionFlowControlMultiplier = 1.5 // DefaultInitialMaxStreamData is the default initial stream-level flow control window for receiving data const DefaultInitialMaxStreamData = (1 << 10) * 512 // 512 kb // DefaultInitialMaxData is the connection-level flow control window for receiving data const DefaultInitialMaxData = ConnectionFlowControlMultiplier * DefaultInitialMaxStreamData // DefaultMaxReceiveStreamFlowControlWindow is the default maximum stream-level flow control window for receiving data const DefaultMaxReceiveStreamFlowControlWindow = 6 * (1 << 20) // 6 MB // DefaultMaxReceiveConnectionFlowControlWindow is the default connection-level flow control window for receiving data const DefaultMaxReceiveConnectionFlowControlWindow = 15 * (1 << 20) // 15 MB // WindowUpdateThreshold is the fraction of the receive window that has to be consumed before an higher offset is advertised to the client const WindowUpdateThreshold = 0.25 // DefaultMaxIncomingStreams is the maximum number of streams that a peer may open const DefaultMaxIncomingStreams = 100 // DefaultMaxIncomingUniStreams is the maximum number of unidirectional streams that a peer may open const DefaultMaxIncomingUniStreams = 100 // MaxServerUnprocessedPackets is the max number of packets stored in the server that are not yet processed. const MaxServerUnprocessedPackets = 1024 // MaxConnUnprocessedPackets is the max number of packets stored in each connection that are not yet processed. const MaxConnUnprocessedPackets = 256 // SkipPacketInitialPeriod is the initial period length used for packet number skipping to prevent an Optimistic ACK attack. // Every time a packet number is skipped, the period is doubled, up to SkipPacketMaxPeriod. const SkipPacketInitialPeriod PacketNumber = 256 // SkipPacketMaxPeriod is the maximum period length used for packet number skipping. const SkipPacketMaxPeriod PacketNumber = 128 * 1024 // MaxAcceptQueueSize is the maximum number of connections that the server queues for accepting. // If the queue is full, new connection attempts will be rejected. const MaxAcceptQueueSize = 32 // TokenValidity is the duration that a (non-retry) token is considered valid const TokenValidity = 24 * time.Hour // RetryTokenValidity is the duration that a retry token is considered valid const RetryTokenValidity = 10 * time.Second // MaxOutstandingSentPackets is maximum number of packets saved for retransmission. // When reached, it imposes a soft limit on sending new packets: // Sending ACKs and retransmission is still allowed, but now new regular packets can be sent. const MaxOutstandingSentPackets = 2 * MaxCongestionWindowPackets // MaxTrackedSentPackets is maximum number of sent packets saved for retransmission. // When reached, no more packets will be sent. // This value *must* be larger than MaxOutstandingSentPackets. const MaxTrackedSentPackets = MaxOutstandingSentPackets * 5 / 4 // MaxNonAckElicitingAcks is the maximum number of packets containing an ACK, // but no ack-eliciting frames, that we send in a row const MaxNonAckElicitingAcks = 19 // MaxStreamFrameSorterGaps is the maximum number of gaps between received StreamFrames // prevents DoS attacks against the streamFrameSorter const MaxStreamFrameSorterGaps = 1000 // MinStreamFrameBufferSize is the minimum data length of a received STREAM frame // that we use the buffer for. This protects against a DoS where an attacker would send us // very small STREAM frames to consume a lot of memory. const MinStreamFrameBufferSize = 128 // MinCoalescedPacketSize is the minimum size of a coalesced packet that we pack. // If a packet has less than this number of bytes, we won't coalesce any more packets onto it. const MinCoalescedPacketSize = 128 // MaxCryptoStreamOffset is the maximum offset allowed on any of the crypto streams. // This limits the size of the ClientHello and Certificates that can be received. const MaxCryptoStreamOffset = 16 * (1 << 10) // MinRemoteIdleTimeout is the minimum value that we accept for the remote idle timeout const MinRemoteIdleTimeout = 5 * time.Second // DefaultIdleTimeout is the default idle timeout const DefaultIdleTimeout = 30 * time.Second // DefaultHandshakeIdleTimeout is the default idle timeout used before handshake completion. const DefaultHandshakeIdleTimeout = 5 * time.Second // DefaultHandshakeTimeout is the default timeout for a connection until the crypto handshake succeeds. const DefaultHandshakeTimeout = 10 * time.Second // MaxKeepAliveInterval is the maximum time until we send a packet to keep a connection alive. // It should be shorter than the time that NATs clear their mapping. const MaxKeepAliveInterval = 20 * time.Second // RetiredConnectionIDDeleteTimeout is the time we keep closed connections around in order to retransmit the CONNECTION_CLOSE. // after this time all information about the old connection will be deleted const RetiredConnectionIDDeleteTimeout = 5 * time.Second // MinStreamFrameSize is the minimum size that has to be left in a packet, so that we add another STREAM frame. // This avoids splitting up STREAM frames into small pieces, which has 2 advantages: // 1. it reduces the framing overhead // 2. it reduces the head-of-line blocking, when a packet is lost const MinStreamFrameSize ByteCount = 128 // MaxPostHandshakeCryptoFrameSize is the maximum size of CRYPTO frames // we send after the handshake completes. const MaxPostHandshakeCryptoFrameSize = 1000 // MaxAckFrameSize is the maximum size for an ACK frame that we write // Due to the varint encoding, ACK frames can grow (almost) indefinitely large. // The MaxAckFrameSize should be large enough to encode many ACK range, // but must ensure that a maximum size ACK frame fits into one packet. const MaxAckFrameSize ByteCount = 1000 // DefaultMaxDatagramFrameSize is the maximum size of a DATAGRAM frame as defined in // https://datatracker.ietf.org/doc/draft-pauly-quic-datagram/. // The size is chosen such that a DATAGRAM frame fits into a QUIC packet. const DefaultMaxDatagramFrameSize ByteCount = 1220 // DatagramRcvQueueLen is the length of the receive queue for DATAGRAM frames (RFC 9221) const DatagramRcvQueueLen = 128 // MaxNumAckRanges is the maximum number of ACK ranges that we send in an ACK frame. // It also serves as a limit for the packet history. // If at any point we keep track of more ranges, old ranges are discarded. const MaxNumAckRanges = 32 // MinPacingDelay is the minimum duration that is used for packet pacing // If the packet packing frequency is higher, multiple packets might be sent at once. // Example: For a packet pacing delay of 200μs, we would send 5 packets at once, wait for 1ms, and so forth. const MinPacingDelay = time.Millisecond // DefaultConnectionIDLength is the connection ID length that is used for multiplexed connections // if no other value is configured. const DefaultConnectionIDLength = 4 // MaxActiveConnectionIDs is the number of connection IDs that we're storing. const MaxActiveConnectionIDs = 4 // MaxIssuedConnectionIDs is the maximum number of connection IDs that we're issuing at the same time. const MaxIssuedConnectionIDs = 6 // PacketsPerConnectionID is the number of packets we send using one connection ID. // If the peer provices us with enough new connection IDs, we switch to a new connection ID. const PacketsPerConnectionID = 10000 // AckDelayExponent is the ack delay exponent used when sending ACKs. const AckDelayExponent = 3 // Estimated timer granularity. // The loss detection timer will not be set to a value smaller than granularity. const TimerGranularity = time.Millisecond // MaxAckDelay is the maximum time by which we delay sending ACKs. const MaxAckDelay = 25 * time.Millisecond // MaxAckDelayInclGranularity is the max_ack_delay including the timer granularity. // This is the value that should be advertised to the peer. const MaxAckDelayInclGranularity = MaxAckDelay + TimerGranularity // KeyUpdateInterval is the maximum number of packets we send or receive before initiating a key update. const KeyUpdateInterval = 100 * 1000 // Max0RTTQueueingDuration is the maximum time that we store 0-RTT packets in order to wait for the corresponding Initial to be received. const Max0RTTQueueingDuration = 100 * time.Millisecond // Max0RTTQueues is the maximum number of connections that we buffer 0-RTT packets for. const Max0RTTQueues = 32 // Max0RTTQueueLen is the maximum number of 0-RTT packets that we buffer for each connection. // When a new connection is created, all buffered packets are passed to the connection immediately. // To avoid blocking, this value has to be smaller than MaxConnUnprocessedPackets. // To avoid packets being dropped as undecryptable by the connection, this value has to be smaller than MaxUndecryptablePackets. const Max0RTTQueueLen = 31