Init commit

gvisor_posix.go

@@ -0,0 +1,118 @@
+package tun
+
+import (
+	"os"
+
+	gBuffer "gvisor.dev/gvisor/pkg/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+
+	"github.com/sagernet/sing/common"
+	"github.com/sagernet/sing/common/buf"
+	"github.com/sagernet/sing/common/rw"
+)
+
+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
+}