protocol

Documentation

Index

• Constants
• Variables
• func IsSupportedVersion(supported []VersionNumber, v VersionNumber) bool
• func IsValidVersion(v VersionNumber) bool
• type ApplicationErrorCode
• type ByteCount
• type ConnectionID
  • func GenerateConnectionID(len int) (ConnectionID, error)
  • func GenerateConnectionIDForInitial() (ConnectionID, error)
  • func ReadConnectionID(r io.Reader, len int) (ConnectionID, error)
  • func (c ConnectionID) Bytes() []byte
  • func (c ConnectionID) Equal(other ConnectionID) bool
  • func (c ConnectionID) Len() int
  • func (c ConnectionID) String() string
• type EncryptionLevel
  • func (e EncryptionLevel) String() string
• type Packet
• type PacketNumber
  • func DecodePacketNumber(packetNumberLength PacketNumberLen, lastPacketNumber PacketNumber, ...) PacketNumber
• type PacketNumberLen
  • func GetPacketNumberLength(packetNumber PacketNumber) PacketNumberLen
  • func GetPacketNumberLengthForHeader(packetNumber, leastUnacked PacketNumber) PacketNumberLen
• type PacketType
  • func (t PacketType) String() string
• type Perspective
  • func (p Perspective) Opposite() Perspective
  • func (p Perspective) String() string
• type StreamID
  • func (s StreamID) InitiatedBy() Perspective
  • func (s StreamID) StreamNum() StreamNum
  • func (s StreamID) Type() StreamType
• type StreamNum
  • func (s StreamNum) StreamID(stype StreamType, pers Perspective) StreamID
• type StreamType
• type VersionNumber
  • func ChooseSupportedVersion(ours, theirs []VersionNumber) (VersionNumber, bool)
  • func GetGreasedVersions(supported []VersionNumber) []VersionNumber
  • func StripGreasedVersions(versions []VersionNumber) []VersionNumber
  • func (vn VersionNumber) String() string
  • func (vn VersionNumber) ToAltSvc() string

Constants

const AckDelayExponent = 3

AckDelayExponent is the ack delay exponent used when sending ACKs.

const ConnectionFlowControlMultiplier = 1.5

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 DefaultAckDelayExponent = 3

DefaultAckDelayExponent is the default ack delay exponent

const DefaultConnectionIDLength = 4

DefaultConnectionIDLength is the connection ID length that is used for multiplexed connections if no other value is configured.

const DefaultHandshakeTimeout = 10 * time.Second

DefaultHandshakeTimeout is the default timeout for a connection until the crypto handshake succeeds.

const DefaultIdleTimeout = 30 * time.Second

DefaultIdleTimeout is the default idle timeout

const DefaultMaxAckDelay = 25 * time.Millisecond

DefaultMaxAckDelay is the default max_ack_delay

const DefaultMaxIncomingStreams = 100

DefaultMaxIncomingStreams is the maximum number of streams that a peer may open

const DefaultMaxIncomingUniStreams = 100

DefaultMaxIncomingUniStreams is the maximum number of unidirectional streams that a peer may open

const DefaultMaxReceiveConnectionFlowControlWindow = 15 * (1 << 20) // 12 MB

DefaultMaxReceiveConnectionFlowControlWindow is the default connection-level flow control window for receiving data, for the server

const DefaultMaxReceiveStreamFlowControlWindow = 6 * (1 << 20) // 6 MB

DefaultMaxReceiveStreamFlowControlWindow is the default maximum stream-level flow control window for receiving data, for the server

const InitialMaxData = ConnectionFlowControlMultiplier * InitialMaxStreamData

InitialMaxData is the connection-level flow control window for receiving data

const InitialMaxStreamData = (1 << 10) * 512 // 512 kb

InitialMaxStreamData is the stream-level flow control window for receiving data

const InvalidPacketNumber = -1

InvalidPacketNumber is a packet number that is never sent. In QUIC, 0 is a valid packet number.

const MaxAcceptQueueSize = 32

MaxAcceptQueueSize is the maximum number of sessions that the server queues for accepting. If the queue is full, new connection attempts will be rejected.

const MaxAckDelay = 25 * time.Millisecond

MaxAckDelay is the maximum time by which we delay sending ACKs.

const MaxAckDelayExponent = 20

MaxAckDelayExponent is the maximum ack delay exponent

const MaxAckDelayInclGranularity = MaxAckDelay + TimerGranularity

MaxAckDelayInclGranularity is the max_ack_delay including the timer granularity. This is the value that should be advertised to the peer.

const MaxByteCount = ByteCount(1<<62 - 1)

MaxByteCount is the maximum value of a ByteCount

const MaxCryptoStreamOffset = 16 * (1 << 10)

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 MaxMaxAckDelay = 1 << 14 * time.Millisecond

MaxMaxAckDelay is the maximum max_ack_delay

const MaxNonAckElicitingAcks = 19

MaxNonAckElicitingAcks is the maximum number of packets containing an ACK, but no ack-eliciting frames, that we send in a row

const MaxOutstandingSentPackets = 2 * defaultMaxCongestionWindowPackets

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 MaxPacketSizeIPv4 = 1252

MaxPacketSizeIPv4 is the maximum packet size that we use for sending IPv4 packets.

const MaxPacketSizeIPv6 = 1232

MaxPacketSizeIPv6 is the maximum packet size that we use for sending IPv6 packets.

const MaxSessionUnprocessedPackets = defaultMaxCongestionWindowPackets

MaxSessionUnprocessedPackets is the max number of packets stored in each session that are not yet processed.

const MaxStreamFrameSorterGaps = 1000

MaxStreamFrameSorterGaps is the maximum number of gaps between received StreamFrames prevents DoS attacks against the streamFrameSorter

const MaxTrackedReceivedAckRanges = defaultMaxCongestionWindowPackets

MaxTrackedReceivedAckRanges is the maximum number of ACK ranges tracked

const MaxTrackedSentPackets = MaxOutstandingSentPackets * 5 / 4

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 MaxTrackedSkippedPackets = 10

MaxTrackedSkippedPackets is the maximum number of skipped packet numbers the SentPacketHandler keep track of for Optimistic ACK attack mitigation

const MaxUndecryptablePackets = 10

MaxUndecryptablePackets limits the number of undecryptable packets that are queued in the session.

const MinConnectionIDLenInitial = 8

MinConnectionIDLenInitial is the minimum length of the destination connection ID on an Initial packet.

const MinInitialPacketSize = 1200

MinInitialPacketSize is the minimum size an Initial packet is required to have.

const MinPacingDelay time.Duration = 100 * time.Microsecond

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 20 microseconds, we would send 5 packets at once, wait for 100 microseconds, and so forth.

const MinRemoteIdleTimeout = 5 * time.Second

MinRemoteIdleTimeout is the minimum value that we accept for the remote idle timeout

const MinStatelessResetSize = 1 + 22 + 16 /* token */

MinStatelessResetSize is the minimum size of a stateless reset packet

const RetiredConnectionIDDeleteTimeout = 5 * time.Second

RetiredConnectionIDDeleteTimeout is the time we keep closed sessions around in order to retransmit the CONNECTION_CLOSE. after this time all information about the old connection will be deleted

const RetryTokenValidity = 10 * time.Second

RetryTokenValidity is the duration that a retry token is considered valid

const TimerGranularity = time.Millisecond

Estimated timer granularity. The loss detection timer will not be set to a value smaller than granularity.

const TokenValidity = 24 * time.Hour

TokenValidity is the duration that a (non-retry) token is considered valid

const WindowUpdateThreshold = 0.25

WindowUpdateThreshold is the fraction of the receive window that has to be consumed before an higher offset is advertised to the client

Variables

var SupportedVersions = []VersionNumber{VersionTLS}

SupportedVersions lists the versions that the server supports must be in sorted descending order

Functions

func IsSupportedVersion

func IsSupportedVersion(supported []VersionNumber, v VersionNumber) bool

IsSupportedVersion returns true if the server supports this version

func IsValidVersion

func IsValidVersion(v VersionNumber) bool

IsValidVersion says if the version is known to quic-go

Types

type ApplicationErrorCode

type ApplicationErrorCode uint16

An ApplicationErrorCode is an application-defined error code.

type ByteCount

type ByteCount uint64

A ByteCount in QUIC

const DefaultBBRMaxCongestionWindow ByteCount = 2000 * DefaultTCPMSS

DefaultBBRMaxCongestionWindow is the default for the max congestion window in BBR algorithm

const DefaultMaxCongestionWindow ByteCount = defaultMaxCongestionWindowPackets * DefaultTCPMSS

DefaultMaxCongestionWindow is the default for the max congestion window

const DefaultTCPMSS ByteCount = 1460

DefaultTCPMSS is the default maximum packet size used in the Linux TCP implementation. Used in QUIC for congestion window computations in bytes.

const InitialCongestionWindow ByteCount = 32 * DefaultTCPMSS

InitialCongestionWindow is the initial congestion window in QUIC packets

const MaxAckFrameSize ByteCount = 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 MaxPostHandshakeCryptoFrameSize ByteCount = 1000

MaxPostHandshakeCryptoFrameSize is the maximum size of CRYPTO frames we send after the handshake completes.

const MaxReceivePacketSize ByteCount = 1452

MaxReceivePacketSize maximum packet size of any QUIC packet, based on ethernet's max size, minus the IP and UDP headers. IPv6 has a 40 byte header, UDP adds an additional 8 bytes. This is a total overhead of 48 bytes. Ethernet's max packet size is 1500 bytes, 1500 - 48 = 1452.

const MinStreamFrameSize ByteCount = 128

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

type ConnectionID

type ConnectionID []byte

A ConnectionID in QUIC

func GenerateConnectionID

func GenerateConnectionID(len int) (ConnectionID, error)

GenerateConnectionID generates a connection ID using cryptographic random

func GenerateConnectionIDForInitial

func GenerateConnectionIDForInitial() (ConnectionID, error)

GenerateConnectionIDForInitial generates a connection ID for the Initial packet. It uses a length randomly chosen between 8 and 18 bytes.

func ReadConnectionID

func ReadConnectionID(r io.Reader, len int) (ConnectionID, error)

ReadConnectionID reads a connection ID of length len from the given io.Reader. It returns io.EOF if there are not enough bytes to read.

func (ConnectionID) Bytes

func (c ConnectionID) Bytes() []byte

Bytes returns the byte representation

func (ConnectionID) Equal

func (c ConnectionID) Equal(other ConnectionID) bool

Equal says if two connection IDs are equal

func (ConnectionID) Len

func (c ConnectionID) Len() int

Len returns the length of the connection ID in bytes

func (ConnectionID) String

func (c ConnectionID) String() string

type EncryptionLevel

type EncryptionLevel int

EncryptionLevel is the encryption level Default value is Unencrypted

const (
	// EncryptionUnspecified is a not specified encryption level
	EncryptionUnspecified EncryptionLevel = iota
	// EncryptionInitial is the Initial encryption level
	EncryptionInitial
	// EncryptionHandshake is the Handshake encryption level
	EncryptionHandshake
	// Encryption1RTT is the 1-RTT encryption level
	Encryption1RTT
)

func (EncryptionLevel) String

func (e EncryptionLevel) String() string

type Packet

type Packet struct {
	PacketNumber PacketNumber
	PacketType   PacketType
	Length       ByteCount
	SendTime     time.Time
}

type PacketNumber

type PacketNumber int64

A PacketNumber in QUIC

const SkipPacketAveragePeriodLength PacketNumber = 500

SkipPacketAveragePeriodLength is the average period length in which one packet number is skipped to prevent an Optimistic ACK attack

func DecodePacketNumber

func DecodePacketNumber(
	packetNumberLength PacketNumberLen,
	lastPacketNumber PacketNumber,
	wirePacketNumber PacketNumber,
) PacketNumber

DecodePacketNumber calculates the packet number based on the received packet number, its length and the last seen packet number

type PacketNumberLen

type PacketNumberLen uint8

PacketNumberLen is the length of the packet number in bytes

const (
	// PacketNumberLenInvalid is the default value and not a valid length for a packet number
	PacketNumberLenInvalid PacketNumberLen = 0
	// PacketNumberLen1 is a packet number length of 1 byte
	PacketNumberLen1 PacketNumberLen = 1
	// PacketNumberLen2 is a packet number length of 2 bytes
	PacketNumberLen2 PacketNumberLen = 2
	// PacketNumberLen3 is a packet number length of 3 bytes
	PacketNumberLen3 PacketNumberLen = 3
	// PacketNumberLen4 is a packet number length of 4 bytes
	PacketNumberLen4 PacketNumberLen = 4
)

func GetPacketNumberLength

func GetPacketNumberLength(packetNumber PacketNumber) PacketNumberLen

GetPacketNumberLength gets the minimum length needed to fully represent the packet number

func GetPacketNumberLengthForHeader

func GetPacketNumberLengthForHeader(packetNumber, leastUnacked PacketNumber) PacketNumberLen

GetPacketNumberLengthForHeader gets the length of the packet number for the public header it never chooses a PacketNumberLen of 1 byte, since this is too short under certain circumstances

type PacketType

type PacketType uint8

The PacketType is the Long Header Type

const (
	// PacketTypeInitial is the packet type of an Initial packet
	PacketTypeInitial PacketType = 1 + iota
	// PacketTypeRetry is the packet type of a Retry packet
	PacketTypeRetry
	// PacketTypeHandshake is the packet type of a Handshake packet
	PacketTypeHandshake
	// PacketType0RTT is the packet type of a 0-RTT packet
	PacketType0RTT
)

func (PacketType) String

func (t PacketType) String() string

type Perspective

type Perspective int

Perspective determines if we're acting as a server or a client

const (
	PerspectiveServer Perspective = 1
	PerspectiveClient Perspective = 2
)

the perspectives

func (Perspective) Opposite

func (p Perspective) Opposite() Perspective

Opposite returns the perspective of the peer

func (Perspective) String

func (p Perspective) String() string

type StreamID

type StreamID int64

A StreamID in QUIC

const InvalidStreamID StreamID = -1

InvalidPacketNumber is a stream ID that is invalid. The first valid stream ID in QUIC is 0.

func (StreamID) InitiatedBy

func (s StreamID) InitiatedBy() Perspective

InitiatedBy says if the stream was initiated by the client or by the server

func (StreamID) StreamNum

func (s StreamID) StreamNum() StreamNum

StreamNum returns how many streams in total are below this Example: for stream 9 it returns 3 (i.e. streams 1, 5 and 9)

func (StreamID) Type

func (s StreamID) Type() StreamType

Type says if this is a unidirectional or bidirectional stream

type StreamNum

type StreamNum int64

StreamNum is the stream number

const (
	// InvalidStreamNum is an invalid stream number.
	InvalidStreamNum = -1
	// MaxStreamCount is the maximum stream count value that can be sent in MAX_STREAMS frames
	// and as the stream count in the transport parameters
	MaxStreamCount StreamNum = 1 << 60
)

func (StreamNum) StreamID

func (s StreamNum) StreamID(stype StreamType, pers Perspective) StreamID

StreamID calculates the stream ID.

type StreamType

type StreamType uint8

StreamType encodes if this is a unidirectional or bidirectional stream

const (
	// StreamTypeUni is a unidirectional stream
	StreamTypeUni StreamType = iota
	// StreamTypeBidi is a bidirectional stream
	StreamTypeBidi
)

type VersionNumber

type VersionNumber uint32

VersionNumber is a version number as int

const (
	VersionTLS      VersionNumber = 0x51474fff
	VersionWhatever VersionNumber = 1 // for when the version doesn't matter
	VersionUnknown  VersionNumber = math.MaxUint32
)

The version numbers, making grepping easier

func ChooseSupportedVersion

func ChooseSupportedVersion(ours, theirs []VersionNumber) (VersionNumber, bool)

ChooseSupportedVersion finds the best version in the overlap of ours and theirs ours is a slice of versions that we support, sorted by our preference (descending) theirs is a slice of versions offered by the peer. The order does not matter. The bool returned indicates if a matching version was found.

func GetGreasedVersions

func GetGreasedVersions(supported []VersionNumber) []VersionNumber

GetGreasedVersions adds one reserved version number to a slice of version numbers, at a random position

func StripGreasedVersions

func StripGreasedVersions(versions []VersionNumber) []VersionNumber

StripGreasedVersions strips all greased versions from a slice of versions

func (VersionNumber) String

func (vn VersionNumber) String() string

func (VersionNumber) ToAltSvc

func (vn VersionNumber) ToAltSvc() string

ToAltSvc returns the representation of the version for the H2 Alt-Svc parameters