Add tun inbound for linux

common/tun/gvisor.go

@@ -0,0 +1,151 @@
+package tun
+
+import (
+	"context"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-box/log"
+	"github.com/sagernet/sing/common"
+	"github.com/sagernet/sing/common/bufio"
+	E "github.com/sagernet/sing/common/exceptions"
+	M "github.com/sagernet/sing/common/metadata"
+
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/icmp"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
+	"gvisor.dev/gvisor/pkg/waiter"
+)
+
+const defaultNIC tcpip.NICID = 1
+
+var _ adapter.Service = (*GVisorTun)(nil)
+
+type GVisorTun struct {
+	ctx     context.Context
+	tunFd   uintptr
+	tunMtu  uint32
+	handler Handler
+	stack   *stack.Stack
+}
+
+func NewGVisor(ctx context.Context, tunFd uintptr, tunMtu uint32, handler Handler) *GVisorTun {
+	return &GVisorTun{
+		ctx:     ctx,
+		tunFd:   tunFd,
+		tunMtu:  tunMtu,
+		handler: handler,
+	}
+}
+
+func (t *GVisorTun) Start() error {
+	linkEndpoint, err := NewEndpoint(t.tunFd, t.tunMtu)
+	if err != nil {
+		return err
+	}
+	ipStack := stack.New(stack.Options{
+		NetworkProtocols: []stack.NetworkProtocolFactory{
+			ipv4.NewProtocol,
+			ipv6.NewProtocol,
+		},
+		TransportProtocols: []stack.TransportProtocolFactory{
+			tcp.NewProtocol,
+			udp.NewProtocol,
+			icmp.NewProtocol4,
+			icmp.NewProtocol6,
+		},
+	})
+	tErr := ipStack.CreateNIC(defaultNIC, linkEndpoint)
+	if tErr != nil {
+		return E.New("create nic: ", tErr)
+	}
+	ipStack.SetRouteTable([]tcpip.Route{
+		{Destination: header.IPv4EmptySubnet, NIC: defaultNIC},
+		{Destination: header.IPv6EmptySubnet, NIC: defaultNIC},
+	})
+	ipStack.SetSpoofing(defaultNIC, true)
+	ipStack.SetPromiscuousMode(defaultNIC, true)
+	bufSize := 20 * 1024
+	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &tcpip.TCPReceiveBufferSizeRangeOption{
+		Min:     1,
+		Default: bufSize,
+		Max:     bufSize,
+	})
+	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &tcpip.TCPSendBufferSizeRangeOption{
+		Min:     1,
+		Default: bufSize,
+		Max:     bufSize,
+	})
+	sOpt := tcpip.TCPSACKEnabled(true)
+	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &sOpt)
+	mOpt := tcpip.TCPModerateReceiveBufferOption(true)
+	ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &mOpt)
+	tcpForwarder := tcp.NewForwarder(ipStack, 0, 1024, func(r *tcp.ForwarderRequest) {
+		var wq waiter.Queue
+		endpoint, err := r.CreateEndpoint(&wq)
+		if err != nil {
+			r.Complete(true)
+			return
+		}
+		r.Complete(false)
+		endpoint.SocketOptions().SetKeepAlive(true)
+		tcpConn := gonet.NewTCPConn(&wq, endpoint)
+		lAddr := tcpConn.RemoteAddr()
+		rAddr := tcpConn.LocalAddr()
+		if lAddr == nil || rAddr == nil {
+			tcpConn.Close()
+			return
+		}
+		go func() {
+			var metadata M.Metadata
+			metadata.Source = M.SocksaddrFromNet(lAddr)
+			metadata.Destination = M.SocksaddrFromNet(rAddr)
+			ctx := log.ContextWithID(t.ctx)
+			hErr := t.handler.NewConnection(ctx, tcpConn, metadata)
+			if hErr != nil {
+				t.handler.NewError(ctx, hErr)
+			}
+		}()
+	})
+	ipStack.SetTransportProtocolHandler(tcp.ProtocolNumber, func(id stack.TransportEndpointID, buffer *stack.PacketBuffer) bool {
+		return tcpForwarder.HandlePacket(id, buffer)
+	})
+	udpForwarder := udp.NewForwarder(ipStack, func(request *udp.ForwarderRequest) {
+		var wq waiter.Queue
+		endpoint, err := request.CreateEndpoint(&wq)
+		if err != nil {
+			return
+		}
+		udpConn := gonet.NewUDPConn(ipStack, &wq, endpoint)
+		lAddr := udpConn.RemoteAddr()
+		rAddr := udpConn.LocalAddr()
+		if lAddr == nil || rAddr == nil {
+			udpConn.Close()
+			return
+		}
+		go func() {
+			var metadata M.Metadata
+			metadata.Source = M.SocksaddrFromNet(lAddr)
+			metadata.Destination = M.SocksaddrFromNet(rAddr)
+			ctx := log.ContextWithID(t.ctx)
+			hErr := t.handler.NewPacketConnection(ctx, bufio.NewPacketConn(&bufio.UnbindPacketConn{ExtendedConn: bufio.NewExtendedConn(udpConn), Addr: M.SocksaddrFromNet(rAddr)}), metadata)
+			if hErr != nil {
+				t.handler.NewError(ctx, hErr)
+			}
+		}()
+	})
+	ipStack.SetTransportProtocolHandler(udp.ProtocolNumber, udpForwarder.HandlePacket)
+	t.stack = ipStack
+	return nil
+}
+
+func (t *GVisorTun) Close() error {
+	return common.Close(
+		common.PtrOrNil(t.stack),
+	)
+}

common/tun/gvisor_linux.go

@@ -0,0 +1,16 @@
+//go:build linux
+
+package tun
+
+import (
+	"gvisor.dev/gvisor/pkg/tcpip/link/fdbased"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+)
+
+func NewEndpoint(tunFd uintptr, tunMtu uint32) (stack.LinkEndpoint, error) {
+	return fdbased.New(&fdbased.Options{
+		FDs:                []int{int(tunFd)},
+		MTU:                tunMtu,
+		PacketDispatchMode: fdbased.PacketMMap,
+	})
+}

common/tun/gvisor_nonlinux.go

@@ -0,0 +1,9 @@
+//go:build !linux
+
+package tun
+
+import "gvisor.dev/gvisor/pkg/tcpip/stack"
+
+func NewEndpoint(tunFd uintptr, tunMtu uint32) (stack.LinkEndpoint, error) {
+	return NewPosixEndpoint(tunFd, tunMtu)
+}

common/tun/gvisor_posix.go

@@ -0,0 +1,118 @@
+package tun
+
+import (
+	"os"
+
+	"github.com/sagernet/sing/common"
+	"github.com/sagernet/sing/common/buf"
+	"github.com/sagernet/sing/common/rw"
+
+	gBuffer "gvisor.dev/gvisor/pkg/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+)
+
+var _ stack.LinkEndpoint = (*PosixEndpoint)(nil)
+
+type PosixEndpoint struct {
+	fd         uintptr
+	mtu        uint32
+	file       *os.File
+	dispatcher stack.NetworkDispatcher
+}
+
+func NewPosixEndpoint(tunFd uintptr, tunMtu uint32) (stack.LinkEndpoint, error) {
+	return &PosixEndpoint{
+		fd:   tunFd,
+		mtu:  tunMtu,
+		file: os.NewFile(tunFd, "tun"),
+	}, nil
+}
+
+func (e *PosixEndpoint) MTU() uint32 {
+	return e.mtu
+}
+
+func (e *PosixEndpoint) MaxHeaderLength() uint16 {
+	return 0
+}
+
+func (e *PosixEndpoint) LinkAddress() tcpip.LinkAddress {
+	return ""
+}
+
+func (e *PosixEndpoint) Capabilities() stack.LinkEndpointCapabilities {
+	return stack.CapabilityNone
+}
+
+func (e *PosixEndpoint) Attach(dispatcher stack.NetworkDispatcher) {
+	if dispatcher == nil && e.dispatcher != nil {
+		e.dispatcher = nil
+		return
+	}
+	if dispatcher != nil && e.dispatcher == nil {
+		e.dispatcher = dispatcher
+		go e.dispatchLoop()
+	}
+}
+
+func (e *PosixEndpoint) dispatchLoop() {
+	_buffer := buf.StackNewPacket()
+	defer common.KeepAlive(_buffer)
+	buffer := common.Dup(_buffer)
+	defer buffer.Release()
+	for {
+		n, err := e.file.Read(buffer.FreeBytes())
+		if err != nil {
+			break
+		}
+		var view gBuffer.View
+		view.Append(buffer.To(n))
+		pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
+			Payload:           view,
+			IsForwardedPacket: true,
+		})
+		defer pkt.DecRef()
+		var p tcpip.NetworkProtocolNumber
+		ipHeader, ok := pkt.Data().PullUp(1)
+		if !ok {
+			continue
+		}
+		switch header.IPVersion(ipHeader) {
+		case header.IPv4Version:
+			p = header.IPv4ProtocolNumber
+		case header.IPv6Version:
+			p = header.IPv6ProtocolNumber
+		default:
+			continue
+		}
+		e.dispatcher.DeliverNetworkPacket(p, pkt)
+	}
+}
+
+func (e *PosixEndpoint) IsAttached() bool {
+	return e.dispatcher != nil
+}
+
+func (e *PosixEndpoint) Wait() {
+}
+
+func (e *PosixEndpoint) ARPHardwareType() header.ARPHardwareType {
+	return header.ARPHardwareNone
+}
+
+func (e *PosixEndpoint) AddHeader(buffer *stack.PacketBuffer) {
+}
+
+func (e *PosixEndpoint) WritePackets(pkts stack.PacketBufferList) (int, tcpip.Error) {
+	var n int
+	for _, packet := range pkts.AsSlice() {
+		_, err := rw.WriteV(e.fd, packet.Slices())
+		if err != nil {
+			return n, &tcpip.ErrAborted{}
+		}
+		n++
+	}
+	return n, nil
+}

common/tun/tun.go

@@ -0,0 +1,12 @@
+package tun
+
+import (
+	E "github.com/sagernet/sing/common/exceptions"
+	N "github.com/sagernet/sing/common/network"
+)
+
+type Handler interface {
+	N.TCPConnectionHandler
+	N.UDPConnectionHandler
+	E.Handler
+}

common/tun/tun_linux.go

@@ -0,0 +1,51 @@
+package tun
+
+import (
+	"net/netip"
+
+	"github.com/vishvananda/netlink"
+	"gvisor.dev/gvisor/pkg/tcpip/link/tun"
+)
+
+func Open(name string) (uintptr, error) {
+	tunFd, err := tun.Open(name)
+	if err != nil {
+		return 0, err
+	}
+	return uintptr(tunFd), nil
+}
+
+func Configure(name string, inet4Address netip.Prefix, inet6Address netip.Prefix, mtu uint32) error {
+	tunLink, err := netlink.LinkByName(name)
+	if err != nil {
+		return err
+	}
+
+	if inet4Address.IsValid() {
+		addr4, _ := netlink.ParseAddr(inet4Address.String())
+		err = netlink.AddrAdd(tunLink, addr4)
+		if err != nil {
+			return err
+		}
+	}
+
+	if inet6Address.IsValid() {
+		addr6, _ := netlink.ParseAddr(inet6Address.String())
+		err = netlink.AddrAdd(tunLink, addr6)
+		if err != nil {
+			return err
+		}
+	}
+
+	err = netlink.LinkSetMTU(tunLink, int(mtu))
+	if err != nil {
+		return err
+	}
+
+	err = netlink.LinkSetUp(tunLink)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

common/tun/tun_other.go

@@ -0,0 +1,11 @@
+//go:build !linux
+
+package tun
+
+import (
+	"os"
+)
+
+func Open(name string) (uintptr, error) {
+	return 0, os.ErrInvalid
+}