snell

package module

v0.0.0-...-a3b2677 Latest Latest Go to latest Published: Nov 3, 2026 License: GPL-2.0 Imports: 21 Imported by: 0

Details

Valid go.mod file
Redistributable license
Tagged version
Stable version
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Repository

github.com/Ember-Moth/sing-snell

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Open Source Insights

README ¶

sing-snell

This fork uses github.com/metacubex/sing buffers, addresses and network interfaces. Import it as github.com/Ember-Moth/sing-snell. Request completion callbacks and optional vectorised/batch writer discovery are owned by this package; they do not require SagerNet/sing.

Surge snell implemented in Go.

Features

All complete features except the v5 QUIC proxy.
Behavior as consistent with the official implementation as possible.
Performance at least on par with the official implementation.

Why

Surge believes that being closed-source and not proliferated can keep this protocol covert, but this is already impossible in 2026. Considering that snell still has advantages that other random-traffic protocols do not possess, such as multiplexing support with complete TCP semantics and traffic-characteristic diversity, we made this instead of reinventing the wheel.

Documentation ¶

Index ¶

Constants
Variables
func ContextWithKeepSession(ctx context.Context) context.Context
func CreateVectorisedWriter(writer any) (N.VectorisedWriter, bool)
func DeriveKey(psk []byte, salt []byte) []byte
func IncreaseNonce(nonce []byte)
func KeepSessionFromContext(ctx context.Context) bool
func NewAEAD(key []byte) (cipher.AEAD, error)
func ReadConnectAddress(reader io.Reader) (M.Socksaddr, error)
func ReadServerError(record *buf.Buffer) error
func ReadUDPRequestAddress(buffer *buf.Buffer) (M.Socksaddr, error)
func ReadUDPResponseAddress(buffer *buf.Buffer) (M.Socksaddr, error)
func WriteConnectAddress(buffer *buf.Buffer, destination M.Socksaddr) error
func WriteUDPRequestAddress(buffer *buf.Buffer, destination M.Socksaddr) error
func WriteUDPResponseAddress(buffer *buf.Buffer, source M.Socksaddr) error
type CloseHandlerFunc
type Handler
type Method
type ObfsConfig
- func (c ObfsConfig) ClientConn(conn net.Conn) net.Conn
- func (c ObfsConfig) ServerConn(conn net.Conn) net.Conn
type ObfsMode
- func ParseObfsMode(name string) (ObfsMode, error)
- func (m ObfsMode) String() string
type PacketBatchWriteCreator
type PacketBatchWriter
- func CreatePacketBatchWriter(writer N.PacketWriter) (PacketBatchWriter, bool)
type Request
- func ReadRequest(reader io.Reader) (Request, error)
- func (r Request) Len() int
- func (r Request) Write(buffer *buf.Buffer) error
type ServerError
- func (e *ServerError) Error() string
- func (e *ServerError) Unwrap() error
type Service
type VectorisedWriteCreator

Constants ¶

View Source

const (
	// Surge 6.4.4 (10661): -[SNObfsHelperHTTP initWithPolicy:] and -[SGObfsHelperTLS initWithPolicy:]
	// substitute these constants when the policy carries no obfs-host / obfs-uri.
	DefaultObfsHost    = "bing.com"
	DefaultObfsURI     = "/"
	DefaultTLSObfsHost = "cloudfront.net"
)

View Source

const (
	HeaderVersion   = 0x04
	HeaderPlainLen  = 7
	AEADTagLen      = 16
	HeaderCipherLen = HeaderPlainLen + AEADTagLen
	SaltLen         = 16
	NonceLen        = 12
	MaxPayloadLen   = 0x3fff
)

View Source

const (
	CommandPing      = 0x00
	CommandConnect   = 0x01
	CommandConnectV2 = 0x05
	CommandUDP       = 0x06
)

View Source

const (
	ReplyTunnel = 0x00
	ReplyPong   = 0x01
	ReplyError  = 0x02
)

View Source

const (
	UDPCommandForward = 0x01
	AddressTypeIPv4   = 0x04
	AddressTypeIPv6   = 0x06
)

View Source

const RequestVersion = 0x01

Variables ¶

View Source

var (
	ErrBadVersion         = E.New("snell: bad header version")
	ErrReservedNonZero    = E.New("snell: reserved header octet is non-zero")
	ErrPayloadTooLarge    = E.New("snell: payload length exceeds maximum")
	ErrUnsupportedCommand = E.New("snell: unsupported command")
	ErrUnexpectedReply    = E.New("snell: unexpected reply opcode")
	ErrMissingPSK         = E.New("snell: missing pre-shared key")
	ErrNoUsers            = E.New("snell: no users")
	ErrBadUserKey         = E.New("snell: bad user key")
	ErrDuplicateUserKey   = E.New("snell: duplicate user key")
)

Functions ¶

func ContextWithKeepSession ¶

func ContextWithKeepSession(ctx context.Context) context.Context

func CreateVectorisedWriter ¶

func CreateVectorisedWriter(writer any) (N.VectorisedWriter, bool)

CreateVectorisedWriter preserves Snell's lazy record writer while using MetaCubeX/sing for buffers and the underlying scatter/gather implementation.

func DeriveKey ¶

func DeriveKey(psk []byte, salt []byte) []byte

Surge 6.7.0 (11520): FUN_1000123d0: AEAD keys are derived with these Argon2id parameters.

func IncreaseNonce ¶

func IncreaseNonce(nonce []byte)

Surge 6.7.0 (11520): FUN_100012944: nonce is u64le(counter) || 0x00000000.

func KeepSessionFromContext ¶

func KeepSessionFromContext(ctx context.Context) bool

func NewAEAD ¶

func NewAEAD(key []byte) (cipher.AEAD, error)

func ReadConnectAddress ¶

func ReadConnectAddress(reader io.Reader) (M.Socksaddr, error)

func ReadServerError ¶

func ReadServerError(record *buf.Buffer) error

func ReadUDPRequestAddress ¶

func ReadUDPRequestAddress(buffer *buf.Buffer) (M.Socksaddr, error)

func ReadUDPResponseAddress ¶

func ReadUDPResponseAddress(buffer *buf.Buffer) (M.Socksaddr, error)

func WriteConnectAddress ¶

func WriteConnectAddress(buffer *buf.Buffer, destination M.Socksaddr) error

Surge 6.7.0 (11520): SNConnectorV4::targetHandshakeData: CONNECT targets are host strings even for literal IPs.

func WriteUDPRequestAddress ¶

func WriteUDPRequestAddress(buffer *buf.Buffer, destination M.Socksaddr) error

func WriteUDPResponseAddress ¶

func WriteUDPResponseAddress(buffer *buf.Buffer, source M.Socksaddr) error

snell-server v6.0.0b4: FUN_001431c0: UDP response sources are emitted as literal IPs only.

Types ¶

type CloseHandlerFunc ¶

type CloseHandlerFunc = func(error)

CloseHandlerFunc completes a logical request, which may share a reusable transport. Closing the transport is not a substitute for this callback.

type Handler ¶

type Handler interface {
	NewConnectionEx(ctx context.Context, conn net.Conn, source M.Socksaddr, destination M.Socksaddr, onClose CloseHandlerFunc)
	NewPacketConnectionEx(ctx context.Context, conn N.PacketConn, source M.Socksaddr, destination M.Socksaddr, onClose CloseHandlerFunc)
}

type Method ¶

type Method interface {
	DialConn(conn net.Conn, destination M.Socksaddr) (net.Conn, error)
	DialEarlyConn(conn net.Conn, destination M.Socksaddr) net.Conn
	DialPacketConn(conn net.Conn) (N.NetPacketConn, error)
}

type ObfsConfig ¶

type ObfsConfig struct {
	Mode ObfsMode
	Host string
	URI  string
}

func (ObfsConfig) ClientConn ¶

func (c ObfsConfig) ClientConn(conn net.Conn) net.Conn

func (ObfsConfig) ServerConn ¶

func (c ObfsConfig) ServerConn(conn net.Conn) net.Conn

type ObfsMode ¶

type ObfsMode int

const (
	ObfsModeNone ObfsMode = iota
	ObfsModeHTTP
	ObfsModeTLS
)

func ParseObfsMode ¶

func ParseObfsMode(name string) (ObfsMode, error)

func (ObfsMode) String ¶

func (m ObfsMode) String() string

type PacketBatchWriteCreator ¶

type PacketBatchWriteCreator interface {
	CreatePacketBatchWriter() (PacketBatchWriter, bool)
}

type PacketBatchWriter ¶

type PacketBatchWriter interface {
	WritePacketBatch(buffers []*buf.Buffer, destinations []M.Socksaddr) error
}

func CreatePacketBatchWriter ¶

func CreatePacketBatchWriter(writer N.PacketWriter) (PacketBatchWriter, bool)

type Request ¶

type Request struct {
	Command     byte
	ClientID    []byte
	Destination M.Socksaddr
}

func ReadRequest ¶

func ReadRequest(reader io.Reader) (Request, error)

func (Request) Len ¶

func (r Request) Len() int

func (Request) Write ¶

func (r Request) Write(buffer *buf.Buffer) error

type ServerError ¶

type ServerError struct {
	net.Conn
	Source M.Socksaddr
	Cause  error
}

snell-server v6.0.0b4: FUN_00141bc0: malformed handshakes are torn down abruptly.

func (*ServerError) Error ¶

func (e *ServerError) Error() string

func (*ServerError) Unwrap ¶

func (e *ServerError) Unwrap() error

type Service ¶

type Service interface {
	NewConnection(ctx context.Context, conn net.Conn, source M.Socksaddr, onClose CloseHandlerFunc) error
}

type VectorisedWriteCreator ¶

type VectorisedWriteCreator interface {
	CreateVectorisedWriter() (N.VectorisedWriter, bool)
}

Source Files ¶

View all Source files

Directories ¶

Path	Synopsis
internal
compat
reuse
snellv4
snellv5
snellv6

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