tun

package module
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Published: Sep 30, 2026 License: GPL-2.0 Imports: 45 Imported by: 13

README

sing-tun

Simple transparent proxy library.

For Linux, Windows, macOS and iOS.

License

Copyright (C) 2022 by nekohasekai <contact-sagernet@sekai.icu>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.

Documentation

Index

Constants

View Source
const (
	DefaultAutoRedirectInputMark  = 0x2023
	DefaultAutoRedirectOutputMark = 0x2024
)
View Source
const (
	DefaultIPRoute2TableIndex                    = 2022
	DefaultIPRoute2RuleIndex                     = 9000
	DefaultIPRoute2AutoRedirectFallbackRuleIndex = 32768
)
View Source
const FlagAndroidVPNUpdate = 1 << iota
View Source
const PacketOffset = 0
View Source
const ProtocolRedirect = "redirect"
View Source
const WithGVisor = false

Variables

View Source
var (
	ErrDrop  = E.New("drop by rule")
	ErrReset = E.New("reset by rule")
)
View Source
var ErrGVisorNotIncluded = E.New(`gVisor is not included in this build, rebuild with -tags with_gvisor`)
View Source
var ErrIncludeAllNetworks = E.New("`system` and `mixed` stack are not available when `includeAllNetworks` is enabled. See https://github.com/SagerNet/sing-tun/issues/25")
View Source
var ErrNetlinkBanned = E.New(
	"netlink socket in Android is banned by Google, " +
		"use the root or system (ADB) user to run sing-box, " +
		"or switch to the sing-box Android graphical interface client",
)
View Source
var ErrNoRoute = E.New("no route to internet")
View Source
var ErrTooManySegments = errors.New("too many segments")

ErrTooManySegments is returned by Device.Read() when segmentation overflows the length of supplied buffers. This error should not cause reads to cease.

Functions

func BroadcastAddr added in v0.2.0

func BroadcastAddr(inet4Address []netip.Prefix) netip.Addr

func CalculateInterfaceName

func CalculateInterfaceName(name string) (tunName string)

func GSOSplit added in v0.4.13

func GSOSplit(in []byte, options GSOOptions, outBufs [][]byte, sizes []int, outOffset int) (int, error)

GSOSplit splits packets from 'in' into outBufs[<index>][outOffset:], writing the size of each element into sizes. It returns the number of buffers populated, and/or an error. Callers may pass an 'in' slice that overlaps with the first element of outBuffers, i.e. &in[0] may be equal to &outBufs[0][outOffset]. GSONone is a valid options.GSOType regardless of the value of options.NeedsCsum. Length of each outBufs element must be greater than or equal to the length of 'in', otherwise output may be silently truncated.

func HasNextAddress added in v0.4.1

func HasNextAddress(prefix netip.Prefix, count int) bool

func PacketDestination added in v0.4.6

func PacketDestination(packet []byte) netip.Addr

func PacketFillHeader added in v0.4.6

func PacketFillHeader(packet []byte, ipVersion int)

func PacketIPVersion added in v0.4.6

func PacketIPVersion(packet []byte) int

Types

type AutoRedirect added in v0.4.1

type AutoRedirect interface {
	Start() error
	Close() error
	UpdateRouteAddressSet()
}

func NewAutoRedirect added in v0.4.1

func NewAutoRedirect(options AutoRedirectOptions) (AutoRedirect, error)

type AutoRedirectOptions added in v0.4.1

type AutoRedirectOptions struct {
	TunOptions             *Options
	Context                context.Context
	Handler                Handler
	Logger                 logger.Logger
	NetworkMonitor         NetworkUpdateMonitor
	InterfaceFinder        control.InterfaceFinder
	TableName              string
	DisableNFTables        bool
	CustomRedirectPort     func() int
	RouteAddressSet        *[]*netipx.IPSet
	RouteExcludeAddressSet *[]*netipx.IPSet
}

type DarwinTUN added in v0.4.7

type DarwinTUN interface {
	Tun
	BatchSize() int
	BatchRead() ([]*buf.Buffer, error)
	BatchWrite(buffers []*buf.Buffer) error
}

type DefaultInterfaceMonitor

type DefaultInterfaceMonitor interface {
	Start() error
	Close() error
	DefaultInterface() *control.Interface
	OverrideAndroidVPN() bool
	AndroidVPNEnabled() bool
	RegisterCallback(callback DefaultInterfaceUpdateCallback) *list.Element[DefaultInterfaceUpdateCallback]
	UnregisterCallback(element *list.Element[DefaultInterfaceUpdateCallback])
}

func NewDefaultInterfaceMonitor

func NewDefaultInterfaceMonitor(networkMonitor NetworkUpdateMonitor, logger logger.Logger, options DefaultInterfaceMonitorOptions) (DefaultInterfaceMonitor, error)

type DefaultInterfaceMonitorOptions

type DefaultInterfaceMonitorOptions struct {
	InterfaceFinder       control.InterfaceFinder
	OverrideAndroidVPN    bool
	UnderNetworkExtension bool
}

type DefaultInterfaceUpdateCallback

type DefaultInterfaceUpdateCallback = func(defaultInterface *control.Interface, flags int)

type DirectRouteContext added in v0.4.8

type DirectRouteContext interface {
	WritePacket(packet []byte) error
}

type DirectRouteDestination added in v0.4.8

type DirectRouteDestination interface {
	WritePacket(packet *buf.Buffer) error
	Close() error
	IsClosed() bool
}

type DirectRouteMapping added in v0.4.8

type DirectRouteMapping struct {
	// contains filtered or unexported fields
}

func NewDirectRouteMapping added in v0.4.8

func NewDirectRouteMapping(timeout time.Duration) *DirectRouteMapping

func (*DirectRouteMapping) Lookup added in v0.4.8

func (m *DirectRouteMapping) Lookup(session DirectRouteSession, constructor func(timeout time.Duration) (DirectRouteDestination, error)) (DirectRouteDestination, error)

type DirectRouteSession added in v0.4.8

type DirectRouteSession struct {
	// IPVersion uint8
	// Network     uint8
	Source      netip.Addr
	Destination netip.Addr
}

type GSOOptions added in v0.4.13

type GSOOptions struct {
	// GSOType represents the type of segmentation offload.
	GSOType GSOType
	// HdrLen is the sum of the layer 3 and 4 header lengths. This field may be
	// zero when GSOType == GSONone.
	HdrLen uint16
	// CsumStart is the head byte index of the packet data to be checksummed,
	// i.e. the start of the TCP or UDP header.
	CsumStart uint16
	// CsumOffset is the offset from CsumStart where the 2-byte checksum value
	// should be placed.
	CsumOffset uint16
	// GSOSize is the size of each segment exclusive of HdrLen. The tail segment
	// may be smaller than this value.
	GSOSize uint16
	// NeedsCsum may be set where GSOType == GSONone. When set, the checksum
	// at CsumStart + CsumOffset must be a partial checksum, i.e. the
	// pseudo-header sum.
	NeedsCsum bool
}

GSOOptions is loosely modeled after struct virtio_net_hdr from the VIRTIO specification. It is a common representation of GSO metadata that can be applied to support packet GSO across tun.Device implementations.

type GSOType added in v0.4.13

type GSOType int

GSOType represents the type of segmentation offload.

const (
	GSONone GSOType = iota
	GSOTCPv4
	GSOTCPv6
	GSOUDPL4
)

func (GSOType) String added in v0.4.13

func (g GSOType) String() string

type Handler

type Handler interface {
	PrepareConnection(
		network string,
		source M.Socksaddr,
		destination M.Socksaddr,
		routeContext DirectRouteContext,
		timeout time.Duration,
	) (DirectRouteDestination, error)
	N.TCPConnectionHandler
	PacketHandler
	E.Handler
}

type LinuxTUN added in v0.2.0

type LinuxTUN interface {
	Tun
	N.FrontHeadroom
	BatchSize() int
	BatchRead(buffers [][]byte, offset int, readN []int) (n int, err error)
	BatchWrite(buffers [][]byte, offset int) (n int, err error)
	TXChecksumOffload() bool
}

type Mipstack added in v0.4.24

type Mipstack struct {
	// contains filtered or unexported fields
}

func (*Mipstack) Close added in v0.4.24

func (s *Mipstack) Close() error

Start and Close are called sequentially by the owner, like the other stacks.

func (*Mipstack) Start added in v0.4.24

func (s *Mipstack) Start() error

type NativeTun

type NativeTun struct {
	// contains filtered or unexported fields
}

func (*NativeTun) BatchRead added in v0.2.0

func (t *NativeTun) BatchRead(buffers [][]byte, offset int, readN []int) (n int, err error)

func (*NativeTun) BatchSize added in v0.2.0

func (t *NativeTun) BatchSize() int

func (*NativeTun) BatchWrite added in v0.2.0

func (t *NativeTun) BatchWrite(buffers [][]byte, offset int) (int, error)

func (*NativeTun) Close

func (t *NativeTun) Close() error

func (*NativeTun) FrontHeadroom added in v0.2.0

func (t *NativeTun) FrontHeadroom() int

func (*NativeTun) Read

func (t *NativeTun) Read(p []byte) (n int, err error)

func (*NativeTun) TXChecksumOffload added in v0.2.0

func (t *NativeTun) TXChecksumOffload() bool

func (*NativeTun) Write

func (t *NativeTun) Write(p []byte) (n int, err error)

type NetworkUpdateCallback

type NetworkUpdateCallback = func()

type NetworkUpdateMonitor

type NetworkUpdateMonitor interface {
	Start() error
	Close() error
	RegisterCallback(callback NetworkUpdateCallback) *list.Element[NetworkUpdateCallback]
	UnregisterCallback(element *list.Element[NetworkUpdateCallback])
}

func NewNetworkUpdateMonitor

func NewNetworkUpdateMonitor(logger logger.Logger) (NetworkUpdateMonitor, error)

type Options

type Options struct {
	Name                                  string
	Inet4Address                          []netip.Prefix
	Inet6Address                          []netip.Prefix
	MTU                                   uint32
	GSO                                   bool
	AutoRoute                             bool
	Inet4Gateway                          netip.Addr
	Inet6Gateway                          netip.Addr
	DNSServers                            []netip.Addr
	IPRoute2TableIndex                    int
	IPRoute2RuleIndex                     int
	IPRoute2AutoRedirectFallbackRuleIndex int
	AutoRedirectMarkMode                  bool
	AutoRedirectInputMark                 uint32
	AutoRedirectOutputMark                uint32
	ExcludeMPTCP                          bool
	Inet4LoopbackAddress                  []netip.Addr
	Inet6LoopbackAddress                  []netip.Addr
	StrictRoute                           bool
	Inet4RouteAddress                     []netip.Prefix
	Inet6RouteAddress                     []netip.Prefix
	Inet4RouteExcludeAddress              []netip.Prefix
	Inet6RouteExcludeAddress              []netip.Prefix
	IncludeInterface                      []string
	ExcludeInterface                      []string
	IncludeUID                            []ranges.Range[uint32]
	ExcludeUID                            []ranges.Range[uint32]
	ExcludeSrcPort                        []ranges.Range[uint16]
	ExcludeDstPort                        []ranges.Range[uint16]
	IncludeAndroidUser                    []int
	IncludePackage                        []string
	ExcludePackage                        []string
	IncludeMACAddress                     []net.HardwareAddr
	ExcludeMACAddress                     []net.HardwareAddr
	InterfaceMonitor                      DefaultInterfaceMonitor
	FileDescriptor                        int
	Logger                                logger.Logger

	// For library usages.
	EXP_DisableDNSHijack bool

	// For darwin tun
	//
	// Safe at every MTU: the darwin pending packet limit is derived from the utun control socket
	// receive buffer.
	EXP_RecvMsgX bool
	// Do not enable. In netif mode (every utun handed out by Network Extension) utun_pkt_input
	// returns ENOSPC without freeing the mbuf once 512 packets are queued
	// (net.utun.max_pending_input), leaking one mbuf per rejected write until reboot; sendmsg_x
	// pushes the write rate past the netif drain rate (about 500k to 700k packets per second on an
	// M4 Pro) and reproduces the device-wide network loss, writev stays below it by its own cost.
	EXP_SendMsgX bool

	// For gvisor
	EXP_ProcessorsPerChannel int
	// contains filtered or unexported fields
}

func (*Options) BuildAndroidRules

func (o *Options) BuildAndroidRules(packageManager PackageManager, errorHandler E.Handler)

func (*Options) BuildAutoRouteRanges added in v0.2.0

func (o *Options) BuildAutoRouteRanges(underNetworkExtension bool) ([]netip.Prefix, error)

func (*Options) ExcludedRanges

func (o *Options) ExcludedRanges() (uidRanges []ranges.Range[uint32])

func (*Options) Inet4GatewayAddr added in v0.4.1

func (o *Options) Inet4GatewayAddr() netip.Addr

func (*Options) Inet6GatewayAddr added in v0.4.1

func (o *Options) Inet6GatewayAddr() netip.Addr

type PackageManager

type PackageManager interface {
	Start() error
	Close() error
	IDByPackage(packageName string) (uint32, bool)
	IDBySharedPackage(sharedPackage string) (uint32, bool)
	PackageByID(id uint32) (string, bool)
	PackagesByID(id uint32) ([]string, bool)
	SharedPackageByID(id uint32) (string, bool)
}

func NewPackageManager

func NewPackageManager(options PackageManagerOptions) (PackageManager, error)

type PackageManagerCallback

type PackageManagerCallback interface {
	OnPackagesUpdated(packages int, sharedUsers int)
}

type PackageManagerOptions added in v0.4.1

type PackageManagerOptions struct {
	Callback PackageManagerCallback

	// Logger is the logger to log errors
	// optional
	Logger logger.Logger
}

type PacketHandler added in v0.4.6

type PacketHandler interface {
	NewPacket(ctx context.Context, key netip.AddrPort, buffer *buf.Buffer, metadata M.Metadata, init func(natConn N.PacketConn) N.PacketWriter)
}

type Session

type Session struct {
	SourceAddress      netip.Addr
	DestinationAddress netip.Addr
	SourcePort         uint16
	DestinationPort    uint16
}

type Stack

type Stack interface {
	Start() error
	Close() error
}

func NewGVisor

func NewGVisor(
	options StackOptions,
) (Stack, error)

func NewMipstack added in v0.4.24

func NewMipstack(options StackOptions) (Stack, error)

func NewMixed added in v0.1.11

func NewMixed(
	options StackOptions,
) (Stack, error)

func NewStack

func NewStack(
	stack string,
	options StackOptions,
) (Stack, error)

func NewSystem

func NewSystem(options StackOptions) (Stack, error)

type StackOptions

type StackOptions struct {
	Context                context.Context
	Tun                    Tun
	TunOptions             Options
	EndpointIndependentNat bool
	UDPTimeout             time.Duration
	ICMPTimeout            time.Duration
	Handler                Handler
	Logger                 logger.Logger
	ForwarderBindInterface bool
	IncludeAllNetworks     bool
	InterfaceFinder        control.InterfaceFinder
	TCPCongestionControl   string
	EnforceBindInterface   bool
}

type System

type System struct {
	// contains filtered or unexported fields
}

func (*System) Close

func (s *System) Close() error

func (*System) Start

func (s *System) Start() error

type TCPNat

type TCPNat struct {
	// contains filtered or unexported fields
}

func NewNat

func NewNat(ctx context.Context, timeout time.Duration) *TCPNat

func (*TCPNat) Lookup

func (n *TCPNat) Lookup(source netip.AddrPort, destination netip.AddrPort) (uint16, error)

func (*TCPNat) LookupBack

func (n *TCPNat) LookupBack(port uint16) *TCPSession

type TCPSession

type TCPSession struct {
	sync.Mutex
	Source      netip.AddrPort
	Destination netip.AddrPort
	LastActive  time.Time
}

type Tun

type Tun interface {
	io.ReadWriter
	Close() error
}

func New added in v0.1.2

func New(options Options) (Tun, error)

type WinTun

type WinTun interface {
	Tun
	ReadPacket() ([]byte, func(), error)
}

Directories

Path Synopsis
internal
fdbased_darwin
Package fdbased provides the implementation of data-link layer endpoints backed by boundary-preserving file descriptors (e.g., TUN devices, seqpacket/datagram sockets).
Package fdbased provides the implementation of data-link layer endpoints backed by boundary-preserving file descriptors (e.g., TUN devices, seqpacket/datagram sockets).
gtcpip/checksum
Package checksum provides the implementation of the encoding and decoding of network protocol headers.
Package checksum provides the implementation of the encoding and decoding of network protocol headers.
gtcpip/header
Package header provides the implementation of the encoding and decoding of network protocol headers.
Package header provides the implementation of the encoding and decoding of network protocol headers.
gtcpip/seqnum
Package seqnum defines the types and methods for TCP sequence numbers such that they fit in 32-bit words and work properly when overflows occur.
Package seqnum defines the types and methods for TCP sequence numbers such that they fit in 32-bit words and work properly when overflows occur.

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