Source File
	event.go

Belonging Package
	github.com/quic-go/quic-go/qlog

package qlog

import (
	"fmt"
	"net/netip"
	"time"

	"github.com/quic-go/quic-go/internal/protocol"
	"github.com/quic-go/quic-go/internal/qerr"
	"github.com/quic-go/quic-go/qlogwriter/jsontext"
)

func milliseconds(dur time.Duration) float64 { return float64(dur.Nanoseconds()) / 1e6 }

type encoderHelper struct {
	enc *jsontext.Encoder
	err error
}

func (h *encoderHelper) WriteToken(t jsontext.Token) {
	if h.err != nil {
		return
	}
	h.err = h.enc.WriteToken(t)
}

type versions []Version

func (v versions) encode(enc *jsontext.Encoder) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginArray)
	for _, e := range v {
		h.WriteToken(jsontext.String(fmt.Sprintf("%x", uint32(e))))
	}
	h.WriteToken(jsontext.EndArray)
	return h.err
}

type RawInfo struct {
	Length        int // full packet length, including header and AEAD authentication tag
	PayloadLength int // length of the packet payload, excluding AEAD tag
}

func (i RawInfo) encode(enc *jsontext.Encoder) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("length"))
	h.WriteToken(jsontext.Uint(uint64(i.Length)))
	if i.PayloadLength != 0 {
		h.WriteToken(jsontext.String("payload_length"))
		h.WriteToken(jsontext.Uint(uint64(i.PayloadLength)))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type PathEndpointInfo struct {
	IPv4 netip.AddrPort
	IPv6 netip.AddrPort
}

func (p PathEndpointInfo) encode(enc *jsontext.Encoder) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	if p.IPv4.IsValid() {
		h.WriteToken(jsontext.String("ip_v4"))
		h.WriteToken(jsontext.String(p.IPv4.Addr().String()))
		h.WriteToken(jsontext.String("port_v4"))
		h.WriteToken(jsontext.Int(int64(p.IPv4.Port())))
	}
	if p.IPv6.IsValid() {
		h.WriteToken(jsontext.String("ip_v6"))
		h.WriteToken(jsontext.String(p.IPv6.Addr().String()))
		h.WriteToken(jsontext.String("port_v6"))
		h.WriteToken(jsontext.Int(int64(p.IPv6.Port())))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type StartedConnection struct {
	Local  PathEndpointInfo
	Remote PathEndpointInfo
}

func (e StartedConnection) Name() string { return "transport:connection_started" }

func (e StartedConnection) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("local"))
	if err := e.Local.encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.String("remote"))
	if err := e.Remote.encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type VersionInformation struct {
	ClientVersions, ServerVersions []Version
	ChosenVersion                  Version
}

func (e VersionInformation) Name() string { return "transport:version_information" }

func (e VersionInformation) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	if len(e.ClientVersions) > 0 {
		h.WriteToken(jsontext.String("client_versions"))
		if err := versions(e.ClientVersions).encode(enc); err != nil {
			return err
		}
	}
	if len(e.ServerVersions) > 0 {
		h.WriteToken(jsontext.String("server_versions"))
		if err := versions(e.ServerVersions).encode(enc); err != nil {
			return err
		}
	}
	h.WriteToken(jsontext.String("chosen_version"))
	h.WriteToken(jsontext.String(fmt.Sprintf("%x", uint32(e.ChosenVersion))))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type ConnectionClosed struct {
	Initiator Initiator

	ConnectionError  *TransportErrorCode
	ApplicationError *ApplicationErrorCode

	Reason string

	Trigger ConnectionCloseTrigger
}

func (e ConnectionClosed) Name() string { return "transport:connection_closed" }

func (e ConnectionClosed) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("initiator"))
	h.WriteToken(jsontext.String(string(e.Initiator)))
	if e.ConnectionError != nil {
		h.WriteToken(jsontext.String("connection_error"))
		if e.ConnectionError.IsCryptoError() {
			h.WriteToken(jsontext.String(fmt.Sprintf("crypto_error_%#x", uint16(*e.ConnectionError))))
		} else {
			switch *e.ConnectionError {
			case qerr.NoError:
				h.WriteToken(jsontext.String("no_error"))
			case qerr.InternalError:
				h.WriteToken(jsontext.String("internal_error"))
			case qerr.ConnectionRefused:
				h.WriteToken(jsontext.String("connection_refused"))
			case qerr.FlowControlError:
				h.WriteToken(jsontext.String("flow_control_error"))
			case qerr.StreamLimitError:
				h.WriteToken(jsontext.String("stream_limit_error"))
			case qerr.StreamStateError:
				h.WriteToken(jsontext.String("stream_state_error"))
			case qerr.FinalSizeError:
				h.WriteToken(jsontext.String("final_size_error"))
			case qerr.FrameEncodingError:
				h.WriteToken(jsontext.String("frame_encoding_error"))
			case qerr.TransportParameterError:
				h.WriteToken(jsontext.String("transport_parameter_error"))
			case qerr.ConnectionIDLimitError:
				h.WriteToken(jsontext.String("connection_id_limit_error"))
			case qerr.ProtocolViolation:
				h.WriteToken(jsontext.String("protocol_violation"))
			case qerr.InvalidToken:
				h.WriteToken(jsontext.String("invalid_token"))
			case qerr.ApplicationErrorErrorCode:
				h.WriteToken(jsontext.String("application_error"))
			case qerr.CryptoBufferExceeded:
				h.WriteToken(jsontext.String("crypto_buffer_exceeded"))
			case qerr.KeyUpdateError:
				h.WriteToken(jsontext.String("key_update_error"))
			case qerr.AEADLimitReached:
				h.WriteToken(jsontext.String("aead_limit_reached"))
			case qerr.NoViablePathError:
				h.WriteToken(jsontext.String("no_viable_path"))
			default:
				h.WriteToken(jsontext.String("unknown"))
				h.WriteToken(jsontext.String("error_code"))
				h.WriteToken(jsontext.Uint(uint64(*e.ConnectionError)))
			}
		}
	}
	if e.ApplicationError != nil {
		h.WriteToken(jsontext.String("application_error"))
		h.WriteToken(jsontext.String("unknown"))
		h.WriteToken(jsontext.String("error_code"))
		h.WriteToken(jsontext.Uint(uint64(*e.ApplicationError)))
	}
	if e.ConnectionError != nil || e.ApplicationError != nil {
		h.WriteToken(jsontext.String("reason"))
		h.WriteToken(jsontext.String(e.Reason))
	}
	if e.Trigger != "" {
		h.WriteToken(jsontext.String("trigger"))
		h.WriteToken(jsontext.String(string(e.Trigger)))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type PacketSent struct {
	Header            PacketHeader
	Raw               RawInfo
	DatagramID        DatagramID
	Frames            []Frame
	ECN               ECN
	IsCoalesced       bool
	Trigger           string
	SupportedVersions []Version
}

func (e PacketSent) Name() string { return "transport:packet_sent" }

func (e PacketSent) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("header"))
	if err := e.Header.encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.String("raw"))
	if err := e.Raw.encode(enc); err != nil {
		return err
	}
	if e.DatagramID != 0 {
		h.WriteToken(jsontext.String("datagram_id"))
		h.WriteToken(jsontext.Uint(uint64(e.DatagramID)))
	}
	if len(e.Frames) > 0 {
		h.WriteToken(jsontext.String("frames"))
		if err := frames(e.Frames).encode(enc); err != nil {
			return err
		}
	}
	if e.IsCoalesced {
		h.WriteToken(jsontext.String("is_coalesced"))
		h.WriteToken(jsontext.True)
	}
	if e.ECN != ECNUnsupported {
		h.WriteToken(jsontext.String("ecn"))
		h.WriteToken(jsontext.String(string(e.ECN)))
	}
	if e.Trigger != "" {
		h.WriteToken(jsontext.String("trigger"))
		h.WriteToken(jsontext.String(e.Trigger))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type PacketReceived struct {
	Header      PacketHeader
	Raw         RawInfo
	DatagramID  DatagramID
	Frames      []Frame
	ECN         ECN
	IsCoalesced bool
	Trigger     string
}

func (e PacketReceived) Name() string { return "transport:packet_received" }

func (e PacketReceived) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("header"))
	if err := e.Header.encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.String("raw"))
	if err := e.Raw.encode(enc); err != nil {
		return err
	}
	if e.DatagramID != 0 {
		h.WriteToken(jsontext.String("datagram_id"))
		h.WriteToken(jsontext.Uint(uint64(e.DatagramID)))
	}
	if len(e.Frames) > 0 {
		h.WriteToken(jsontext.String("frames"))
		if err := frames(e.Frames).encode(enc); err != nil {
			return err
		}
	}
	if e.IsCoalesced {
		h.WriteToken(jsontext.String("is_coalesced"))
		h.WriteToken(jsontext.True)
	}
	if e.ECN != ECNUnsupported {
		h.WriteToken(jsontext.String("ecn"))
		h.WriteToken(jsontext.String(string(e.ECN)))
	}
	if e.Trigger != "" {
		h.WriteToken(jsontext.String("trigger"))
		h.WriteToken(jsontext.String(e.Trigger))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type VersionNegotiationReceived struct {
	Header            PacketHeaderVersionNegotiation
	SupportedVersions []Version
}

func (e VersionNegotiationReceived) Name() string { return "transport:packet_received" }

func (e VersionNegotiationReceived) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("header"))
	if err := e.Header.encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.String("supported_versions"))
	if err := versions(e.SupportedVersions).encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type VersionNegotiationSent struct {
	Header            PacketHeaderVersionNegotiation
	SupportedVersions []Version
}

func (e VersionNegotiationSent) Name() string { return "transport:packet_sent" }

func (e VersionNegotiationSent) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("header"))
	if err := e.Header.encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.String("supported_versions"))
	if err := versions(e.SupportedVersions).encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type PacketBuffered struct {
	Header     PacketHeader
	Raw        RawInfo
	DatagramID DatagramID
}

func (e PacketBuffered) Name() string { return "transport:packet_buffered" }

func (e PacketBuffered) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("header"))
	if err := e.Header.encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.String("raw"))
	if err := e.Raw.encode(enc); err != nil {
		return err
	}
	if e.DatagramID != 0 {
		h.WriteToken(jsontext.String("datagram_id"))
		h.WriteToken(jsontext.Uint(uint64(e.DatagramID)))
	}
	h.WriteToken(jsontext.String("trigger"))
	h.WriteToken(jsontext.String("keys_unavailable"))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

// PacketDropped is the transport:packet_dropped event.
type PacketDropped struct {
	Header     PacketHeader
	Raw        RawInfo
	DatagramID DatagramID
	Trigger    PacketDropReason
}

func (e PacketDropped) Name() string { return "transport:packet_dropped" }

func (e PacketDropped) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("header"))
	if err := e.Header.encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.String("raw"))
	if err := e.Raw.encode(enc); err != nil {
		return err
	}
	if e.DatagramID != 0 {
		h.WriteToken(jsontext.String("datagram_id"))
		h.WriteToken(jsontext.Uint(uint64(e.DatagramID)))
	}
	h.WriteToken(jsontext.String("trigger"))
	h.WriteToken(jsontext.String(string(e.Trigger)))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type MTUUpdated struct {
	Value int
	Done  bool
}

func (e MTUUpdated) Name() string { return "recovery:mtu_updated" }

func (e MTUUpdated) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("mtu"))
	h.WriteToken(jsontext.Uint(uint64(e.Value)))
	h.WriteToken(jsontext.String("done"))
	h.WriteToken(jsontext.Bool(e.Done))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

// MetricsUpdated logs RTT and congestion metrics as defined in the
// recovery:metrics_updated event.
// The PTO count is logged via PTOCountUpdated.
type MetricsUpdated struct {
	MinRTT           time.Duration
	SmoothedRTT      time.Duration
	LatestRTT        time.Duration
	RTTVariance      time.Duration
	CongestionWindow int
	BytesInFlight    int
	PacketsInFlight  int
}

func (e MetricsUpdated) Name() string { return "recovery:metrics_updated" }

func (e MetricsUpdated) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	if e.MinRTT != 0 {
		h.WriteToken(jsontext.String("min_rtt"))
		h.WriteToken(jsontext.Float(milliseconds(e.MinRTT)))
	}
	if e.SmoothedRTT != 0 {
		h.WriteToken(jsontext.String("smoothed_rtt"))
		h.WriteToken(jsontext.Float(milliseconds(e.SmoothedRTT)))
	}
	if e.LatestRTT != 0 {
		h.WriteToken(jsontext.String("latest_rtt"))
		h.WriteToken(jsontext.Float(milliseconds(e.LatestRTT)))
	}
	if e.RTTVariance != 0 {
		h.WriteToken(jsontext.String("rtt_variance"))
		h.WriteToken(jsontext.Float(milliseconds(e.RTTVariance)))
	}
	if e.CongestionWindow != 0 {
		h.WriteToken(jsontext.String("congestion_window"))
		h.WriteToken(jsontext.Uint(uint64(e.CongestionWindow)))
	}
	if e.BytesInFlight != 0 {
		h.WriteToken(jsontext.String("bytes_in_flight"))
		h.WriteToken(jsontext.Uint(uint64(e.BytesInFlight)))
	}
	if e.PacketsInFlight != 0 {
		h.WriteToken(jsontext.String("packets_in_flight"))
		h.WriteToken(jsontext.Uint(uint64(e.PacketsInFlight)))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

// PTOCountUpdated logs the pto_count value of the
// recovery:metrics_updated event.
type PTOCountUpdated struct {
	PTOCount uint32
}

func (e PTOCountUpdated) Name() string { return "recovery:metrics_updated" }

func (e PTOCountUpdated) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("pto_count"))
	h.WriteToken(jsontext.Uint(uint64(e.PTOCount)))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type PacketLost struct {
	Header  PacketHeader
	Trigger PacketLossReason
}

func (e PacketLost) Name() string { return "recovery:packet_lost" }

func (e PacketLost) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("header"))
	if err := e.Header.encode(enc); err != nil {
		return err
	}
	h.WriteToken(jsontext.String("trigger"))
	h.WriteToken(jsontext.String(string(e.Trigger)))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type SpuriousLoss struct {
	EncryptionLevel  protocol.EncryptionLevel
	PacketNumber     protocol.PacketNumber
	PacketReordering uint64
	TimeReordering   time.Duration
}

func (e SpuriousLoss) Name() string { return "recovery:spurious_loss" }

func (e SpuriousLoss) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("packet_number_space"))
	h.WriteToken(jsontext.String(encLevelToPacketNumberSpace(e.EncryptionLevel)))
	h.WriteToken(jsontext.String("packet_number"))
	h.WriteToken(jsontext.Uint(uint64(e.PacketNumber)))
	h.WriteToken(jsontext.String("reordering_packets"))
	h.WriteToken(jsontext.Uint(e.PacketReordering))
	h.WriteToken(jsontext.String("reordering_time"))
	h.WriteToken(jsontext.Float(milliseconds(e.TimeReordering)))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type KeyUpdated struct {
	Trigger  KeyUpdateTrigger
	KeyType  KeyType
	KeyPhase KeyPhase // only set for 1-RTT keys
	// we don't log the keys here, so we don't need `old` and `new`.
}

func (e KeyUpdated) Name() string { return "security:key_updated" }

func (e KeyUpdated) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("trigger"))
	h.WriteToken(jsontext.String(string(e.Trigger)))
	h.WriteToken(jsontext.String("key_type"))
	h.WriteToken(jsontext.String(string(e.KeyType)))
	if e.KeyType == KeyTypeClient1RTT || e.KeyType == KeyTypeServer1RTT {
		h.WriteToken(jsontext.String("key_phase"))
		h.WriteToken(jsontext.Uint(uint64(e.KeyPhase)))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type KeyDiscarded struct {
	KeyType  KeyType
	KeyPhase KeyPhase // only set for 1-RTT keys
}

func (e KeyDiscarded) Name() string { return "security:key_discarded" }

func (e KeyDiscarded) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	if e.KeyType != KeyTypeClient1RTT && e.KeyType != KeyTypeServer1RTT {
		h.WriteToken(jsontext.String("trigger"))
		h.WriteToken(jsontext.String("tls"))
	}
	h.WriteToken(jsontext.String("key_type"))
	h.WriteToken(jsontext.String(string(e.KeyType)))
	if e.KeyType == KeyTypeClient1RTT || e.KeyType == KeyTypeServer1RTT {
		h.WriteToken(jsontext.String("key_phase"))
		h.WriteToken(jsontext.Uint(uint64(e.KeyPhase)))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type ParametersSet struct {
	Restore                         bool
	Initiator                       Initiator
	SentBy                          protocol.Perspective
	OriginalDestinationConnectionID protocol.ConnectionID
	InitialSourceConnectionID       protocol.ConnectionID
	RetrySourceConnectionID         *protocol.ConnectionID
	StatelessResetToken             *protocol.StatelessResetToken
	DisableActiveMigration          bool
	MaxIdleTimeout                  time.Duration
	MaxUDPPayloadSize               protocol.ByteCount
	AckDelayExponent                uint8
	MaxAckDelay                     time.Duration
	ActiveConnectionIDLimit         uint64
	InitialMaxData                  protocol.ByteCount
	InitialMaxStreamDataBidiLocal   protocol.ByteCount
	InitialMaxStreamDataBidiRemote  protocol.ByteCount
	InitialMaxStreamDataUni         protocol.ByteCount
	InitialMaxStreamsBidi           int64
	InitialMaxStreamsUni            int64
	PreferredAddress                *PreferredAddress
	MaxDatagramFrameSize            protocol.ByteCount
	EnableResetStreamAt             bool
}

func (e ParametersSet) Name() string {
	if e.Restore {
		return "transport:parameters_restored"
	}
	return "transport:parameters_set"
}

func (e ParametersSet) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	if !e.Restore {
		h.WriteToken(jsontext.String("initiator"))
		h.WriteToken(jsontext.String(string(e.Initiator)))
		if e.SentBy == protocol.PerspectiveServer {
			h.WriteToken(jsontext.String("original_destination_connection_id"))
			h.WriteToken(jsontext.String(e.OriginalDestinationConnectionID.String()))
			if e.StatelessResetToken != nil {
				h.WriteToken(jsontext.String("stateless_reset_token"))
				h.WriteToken(jsontext.String(fmt.Sprintf("%x", e.StatelessResetToken[:])))
			}
			if e.RetrySourceConnectionID != nil {
				h.WriteToken(jsontext.String("retry_source_connection_id"))
				h.WriteToken(jsontext.String((*e.RetrySourceConnectionID).String()))
			}
		}
		h.WriteToken(jsontext.String("initial_source_connection_id"))
		h.WriteToken(jsontext.String(e.InitialSourceConnectionID.String()))
	}
	h.WriteToken(jsontext.String("disable_active_migration"))
	h.WriteToken(jsontext.Bool(e.DisableActiveMigration))
	if e.MaxIdleTimeout != 0 {
		h.WriteToken(jsontext.String("max_idle_timeout"))
		h.WriteToken(jsontext.Float(milliseconds(e.MaxIdleTimeout)))
	}
	if e.MaxUDPPayloadSize != 0 {
		h.WriteToken(jsontext.String("max_udp_payload_size"))
		h.WriteToken(jsontext.Int(int64(e.MaxUDPPayloadSize)))
	}
	if e.AckDelayExponent != 0 {
		h.WriteToken(jsontext.String("ack_delay_exponent"))
		h.WriteToken(jsontext.Uint(uint64(e.AckDelayExponent)))
	}
	if e.MaxAckDelay != 0 {
		h.WriteToken(jsontext.String("max_ack_delay"))
		h.WriteToken(jsontext.Float(milliseconds(e.MaxAckDelay)))
	}
	if e.ActiveConnectionIDLimit != 0 {
		h.WriteToken(jsontext.String("active_connection_id_limit"))
		h.WriteToken(jsontext.Uint(e.ActiveConnectionIDLimit))
	}
	if e.InitialMaxData != 0 {
		h.WriteToken(jsontext.String("initial_max_data"))
		h.WriteToken(jsontext.Int(int64(e.InitialMaxData)))
	}
	if e.InitialMaxStreamDataBidiLocal != 0 {
		h.WriteToken(jsontext.String("initial_max_stream_data_bidi_local"))
		h.WriteToken(jsontext.Int(int64(e.InitialMaxStreamDataBidiLocal)))
	}
	if e.InitialMaxStreamDataBidiRemote != 0 {
		h.WriteToken(jsontext.String("initial_max_stream_data_bidi_remote"))
		h.WriteToken(jsontext.Int(int64(e.InitialMaxStreamDataBidiRemote)))
	}
	if e.InitialMaxStreamDataUni != 0 {
		h.WriteToken(jsontext.String("initial_max_stream_data_uni"))
		h.WriteToken(jsontext.Int(int64(e.InitialMaxStreamDataUni)))
	}
	if e.InitialMaxStreamsBidi != 0 {
		h.WriteToken(jsontext.String("initial_max_streams_bidi"))
		h.WriteToken(jsontext.Int(e.InitialMaxStreamsBidi))
	}
	if e.InitialMaxStreamsUni != 0 {
		h.WriteToken(jsontext.String("initial_max_streams_uni"))
		h.WriteToken(jsontext.Int(e.InitialMaxStreamsUni))
	}
	if e.PreferredAddress != nil {
		h.WriteToken(jsontext.String("preferred_address"))
		if err := e.PreferredAddress.encode(enc); err != nil {
			return err
		}
	}
	if e.MaxDatagramFrameSize != protocol.InvalidByteCount {
		h.WriteToken(jsontext.String("max_datagram_frame_size"))
		h.WriteToken(jsontext.Int(int64(e.MaxDatagramFrameSize)))
	}
	if e.EnableResetStreamAt {
		h.WriteToken(jsontext.String("reset_stream_at"))
		h.WriteToken(jsontext.True)
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type PreferredAddress struct {
	IPv4, IPv6          netip.AddrPort
	ConnectionID        protocol.ConnectionID
	StatelessResetToken protocol.StatelessResetToken
}

func (a PreferredAddress) encode(enc *jsontext.Encoder) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	if a.IPv4.IsValid() {
		h.WriteToken(jsontext.String("ip_v4"))
		h.WriteToken(jsontext.String(a.IPv4.Addr().String()))
		h.WriteToken(jsontext.String("port_v4"))
		h.WriteToken(jsontext.Uint(uint64(a.IPv4.Port())))
	}
	if a.IPv6.IsValid() {
		h.WriteToken(jsontext.String("ip_v6"))
		h.WriteToken(jsontext.String(a.IPv6.Addr().String()))
		h.WriteToken(jsontext.String("port_v6"))
		h.WriteToken(jsontext.Uint(uint64(a.IPv6.Port())))
	}
	h.WriteToken(jsontext.String("connection_id"))
	h.WriteToken(jsontext.String(a.ConnectionID.String()))
	h.WriteToken(jsontext.String("stateless_reset_token"))
	h.WriteToken(jsontext.String(fmt.Sprintf("%x", a.StatelessResetToken)))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type LossTimerUpdated struct {
	Type      LossTimerUpdateType
	TimerType TimerType
	EncLevel  EncryptionLevel
	Time      time.Time
}

func (e LossTimerUpdated) Name() string { return "recovery:loss_timer_updated" }

func (e LossTimerUpdated) Encode(enc *jsontext.Encoder, t time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("event_type"))
	h.WriteToken(jsontext.String(string(e.Type)))
	h.WriteToken(jsontext.String("timer_type"))
	h.WriteToken(jsontext.String(string(e.TimerType)))
	h.WriteToken(jsontext.String("packet_number_space"))
	h.WriteToken(jsontext.String(encLevelToPacketNumberSpace(e.EncLevel)))
	if e.Type == LossTimerUpdateTypeSet {
		h.WriteToken(jsontext.String("delta"))
		h.WriteToken(jsontext.Float(milliseconds(e.Time.Sub(t))))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type eventLossTimerCanceled struct{}

func (e eventLossTimerCanceled) Name() string { return "recovery:loss_timer_updated" }

func (e eventLossTimerCanceled) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("event_type"))
	h.WriteToken(jsontext.String("cancelled"))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type CongestionStateUpdated struct {
	State CongestionState
}

func (e CongestionStateUpdated) Name() string { return "recovery:congestion_state_updated" }

func (e CongestionStateUpdated) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("new"))
	h.WriteToken(jsontext.String(e.State.String()))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type ECNStateUpdated struct {
	State   ECNState
	Trigger string
}

func (e ECNStateUpdated) Name() string { return "recovery:ecn_state_updated" }

func (e ECNStateUpdated) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("new"))
	h.WriteToken(jsontext.String(string(e.State)))
	if e.Trigger != "" {
		h.WriteToken(jsontext.String("trigger"))
		h.WriteToken(jsontext.String(e.Trigger))
	}
	h.WriteToken(jsontext.EndObject)
	return h.err
}

type ALPNInformation struct {
	ChosenALPN string
}

func (e ALPNInformation) Name() string { return "transport:alpn_information" }

func (e ALPNInformation) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("chosen_alpn"))
	h.WriteToken(jsontext.String(e.ChosenALPN))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

// DebugEvent is a generic event that can be used to log arbitrary messages.
type DebugEvent struct {
	EventName string
	Message   string
}

func (e DebugEvent) Name() string {
	if e.EventName == "" {
		return "transport:debug"
	}
	return fmt.Sprintf("transport:%s", e.EventName)
}

func (e DebugEvent) Encode(enc *jsontext.Encoder, _ time.Time) error {
	h := encoderHelper{enc: enc}
	h.WriteToken(jsontext.BeginObject)
	h.WriteToken(jsontext.String("message"))
	h.WriteToken(jsontext.String(e.Message))
	h.WriteToken(jsontext.EndObject)
	return h.err
}

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Golds is a Go 101 project developed by Tapir Liu.
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