protocol

Documentation

Index

• Constants
• Variables
• func IsSupportedVersion(supported []VersionNumber, v VersionNumber) bool
• func IsValidVersion(v VersionNumber) bool
• func UseRetireBugBackwardsCompatibilityMode(enabled bool, 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 ECN
• type EncryptionLevel
  • func (e EncryptionLevel) String() string
• type KeyPhase
  • func (p KeyPhase) Bit() KeyPhaseBit
• type KeyPhaseBit
  • func (p KeyPhaseBit) String() string
• type PacketNumber
  • func DecodePacketNumber(packetNumberLength PacketNumberLen, lastPacketNumber PacketNumber, ...) PacketNumber
• type 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 StatelessResetToken
• 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

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 DatagramRcvQueueLen = 128

DatagramRcvQueueLen is the length of the receive queue for DATAGRAM frames. See https://datatracker.ietf.org/doc/draft-pauly-quic-datagram/.

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 DefaultHandshakeIdleTimeout = 5 * time.Second

DefaultHandshakeIdleTimeout is the default idle timeout used before handshake completion.

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) // 15 MB

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

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

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

const DesiredReceiveBufferSize = (1 << 20) * 2 // 2 MB

DesiredReceiveBufferSize is the kernel UDP receive buffer size that we'd like to use.

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 InitialPacketSizeIPv4 = 1252

InitialPacketSizeIPv4 is the maximum packet size that we use for sending IPv4 packets.

const InitialPacketSizeIPv6 = 1232

InitialPacketSizeIPv6 is the maximum packet size that we use for sending IPv6 packets.

const InvalidPacketLimitAES = 1 << 52

InvalidPacketLimitAES is the maximum number of packets that we can fail to decrypt when using AEAD_AES_128_GCM or AEAD_AES_265_GCM.

const InvalidPacketLimitChaCha = 1 << 36

InvalidPacketLimitChaCha is the maximum number of packets that we can fail to decrypt when using AEAD_CHACHA20_POLY1305.

const KeyUpdateInterval = 100 * 1000

KeyUpdateInterval is the maximum number of packets we send or receive before initiating a key update.

const Max0RTTQueueLen = 31

Max0RTTQueueLen is the maximum number of 0-RTT packets that we buffer for each connection. When a new session is created, all buffered packets are passed to the session immediately. To avoid blocking, this value has to be smaller than MaxSessionUnprocessedPackets. To avoid packets being dropped as undecryptable by the session, this value has to be smaller than MaxUndecryptablePackets.

const Max0RTTQueueingDuration = 100 * time.Millisecond

Max0RTTQueueingDuration is the maximum time that we store 0-RTT packets in order to wait for the corresponding Initial to be received.

const Max0RTTQueues = 32

Max0RTTQueues is the maximum number of connections that we buffer 0-RTT packets for.

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 MaxActiveConnectionIDs = 4

MaxActiveConnectionIDs is the number of connection IDs that we're storing.

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

MaxByteCount is the maximum value of a ByteCount

const MaxCongestionWindowPackets = 10000

MaxCongestionWindowPackets is the maximum congestion window in packet.

const MaxConnIDLen = 20

MaxConnIDLen is the maximum length of the connection ID

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 MaxIssuedConnectionIDs = 6

MaxIssuedConnectionIDs is the maximum number of connection IDs that we're issuing at the same time.

const MaxKeepAliveInterval = 20 * 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 MaxMaxAckDelay = (1<<14 - 1) * 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 MaxNumAckRanges = 32

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 MaxOutstandingSentPackets = 2 * MaxCongestionWindowPackets

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 MaxPostHandshakeCryptoFrameSize = 1000

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

const MaxServerUnprocessedPackets = 1024

MaxServerUnprocessedPackets is the max number of packets stored in the server that are not yet processed.

const MaxSessionUnprocessedPackets = 256

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 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 MaxUndecryptablePackets = 32

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

const MinCoalescedPacketSize = 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 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.Millisecond

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 MinRemoteIdleTimeout = 5 * time.Second

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

const MinStatelessResetSize = 1 + 20 + 4 + 1 + 16 /* token */

MinStatelessResetSize is the minimum size of a stateless reset packet that we send

const MinStreamFrameBufferSize = 128

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 MinUnknownVersionPacketSize = MinInitialPacketSize

MinUnknownVersionPacketSize is the minimum size a packet with an unknown version needs to have in order to trigger a Version Negotiation packet.

const PacketsPerConnectionID = 10000

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 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

func UseRetireBugBackwardsCompatibilityMode

func UseRetireBugBackwardsCompatibilityMode(enabled bool, v VersionNumber) bool

UseRetireBugBackwardsCompatibilityMode says if it is necessary to use the backwards compatilibity mode. This is only the case if it 1. is enabled and 2. draft-29 is used.

Types

type ApplicationErrorCode

type ApplicationErrorCode uint64

An ApplicationErrorCode is an application-defined error code.

type ByteCount

type ByteCount int64

A ByteCount in QUIC

const InvalidByteCount ByteCount = -1

InvalidByteCount is an invalid byte count

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 MaxDatagramFrameSize ByteCount = 1200

MaxDatagramFrameSize 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 MaxPacketBufferSize ByteCount = 1452

MaxPacketBufferSize 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 20 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 ECN

type ECN uint8

const (
	ECNNon ECN = iota // 00
	ECT1              // 01
	ECT0              // 10
	ECNCE             // 11
)

type EncryptionLevel

type EncryptionLevel uint8

EncryptionLevel is the encryption level Default value is Unencrypted

const (
	// EncryptionInitial is the Initial encryption level
	EncryptionInitial EncryptionLevel = 1 + iota
	// EncryptionHandshake is the Handshake encryption level
	EncryptionHandshake
	// Encryption0RTT is the 0-RTT encryption level
	Encryption0RTT
	// Encryption1RTT is the 1-RTT encryption level
	Encryption1RTT
)

func (EncryptionLevel) String

func (e EncryptionLevel) String() string

type KeyPhase

type KeyPhase uint64

KeyPhase is the key phase

func (KeyPhase) Bit

func (p KeyPhase) Bit() KeyPhaseBit

Bit determines the key phase bit

type KeyPhaseBit

type KeyPhaseBit uint8

KeyPhaseBit is the key phase bit

const (
	// KeyPhaseUndefined is an undefined key phase
	KeyPhaseUndefined KeyPhaseBit = iota
	// KeyPhaseZero is key phase 0
	KeyPhaseZero
	// KeyPhaseOne is key phase 1
	KeyPhaseOne
)

func (KeyPhaseBit) String

func (p KeyPhaseBit) String() string

type PacketNumber

type PacketNumber int64

A PacketNumber in QUIC

const InvalidPacketNumber PacketNumber = -1

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

const SkipPacketInitialPeriod PacketNumber = 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 SkipPacketMaxPeriod PacketNumber = 128 * 1024

SkipPacketMaxPeriod is the maximum period length used for packet number skipping.

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 (
	// 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 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 StatelessResetToken

type StatelessResetToken [16]byte

A StatelessResetToken is a stateless reset token.

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
	VersionDraft29  VersionNumber = 0xff00001d
	VersionDraft32  VersionNumber = 0xff000020
	VersionDraft34  VersionNumber = 0xff000022 // If everything goes according to plan at the IETF, this will one day be QUIC v1.
)

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