1 files changed, 135 insertions, 0 deletions
diff --git a/pkg/tcpip/sample/wg_tunnel/gtun.go b/pkg/tcpip/sample/wg_tunnel/gtun.go
new file mode 100644
index 000000000..d641fc42d
--- /dev/null
+++ b/pkg/tcpip/sample/wg_tunnel/gtun.go
@@ -0,0 +1,135 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/link/channel"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+	wgtun "golang.zx2c4.com/wireguard/tun"
+)
+
+type GoTun struct {
+	events chan wgtun.Event
+	ch *channel.Endpoint
+	stack *stack.Stack
+	ctx context.Context
+	cancel context.CancelFunc
+}
+
+func (tun *GoTun) File() *os.File {
+	fmt.Println("File")
+	return nil
+}
+
+func (tun *GoTun) Read(buff []byte, offset int) (int, error) {
+	fmt.Println("Read ", len(buff), offset)
+
+	p, ok := tun.ch.ReadContext(tun.ctx)
+	if ok == false {
+		fmt.Println("Read error")
+		return 0, nil // FIXME error
+	}
+	vv := p.Pkt.Data
+	v := vv.ToView()
+	h := p.Pkt.Header.View()
+	fmt.Println("Read packet", vv.Size(), len(v), len(h), h)
+
+	if len(buff) - offset < len(h) + len(v) {
+		fmt.Println("Short buffer")
+		return 0, nil // FIXME error
+	}
+
+	copy(buff[offset:], h)
+	copy(buff[offset+len(h):], v)
+	return len(h)+len(v), nil
+}
+
+func versionToProtocol(version int) tcpip.NetworkProtocolNumber {
+	switch version {
+	case header.IPv4Version: return header.IPv4ProtocolNumber
+	case header.IPv6Version: return header.IPv6ProtocolNumber
+	}
+
+	return 0
+}
+
+func (tun *GoTun) Write(buff []byte, offset int) (int, error) {
+	size := len(buff) - offset
+	fmt.Println("Write ", len(buff), offset, size)
+
+	if size < 1 {
+		return 0, nil	// FIXME error
+	}
+
+	buffSlice := buff[offset : offset+size]
+
+	pkt := tcpip.PacketBuffer{
+		Data: buffer.NewViewFromBytes(buffSlice).ToVectorisedView(),
+	}
+	//version := buff[offset] & 0x0f
+	protocol := versionToProtocol(header.IPVersion(buffSlice))
+	netProto := tun.stack.NetworkProtocolInstance(protocol)
+	if netProto == nil {
+		fmt.Println("Write not ok")
+		return 0, nil
+	}
+	src, dst := netProto.ParseAddresses(pkt.Data.First())
+	fmt.Println("Write ", src, dst)
+	// TODO change destination address
+	tun.ch.InjectInbound(protocol, pkt) // FIXME detect protocol number
+
+	return size, nil
+}
+
+func (tun *GoTun) Flush() error {
+	// TODO: can flushing be implemented by buffering and using sendmmsg?
+	fmt.Println("Flush")
+	return nil
+}
+
+func (tun *GoTun) MTU() (int, error) {
+	fmt.Println("MTU")
+	return 1280, nil
+}
+
+func (tun *GoTun) Name() (string, error) {
+	fmt.Println("Name")
+	return "foobar", nil
+}
+
+func (tun *GoTun) Events() chan wgtun.Event {
+	fmt.Println("Events")
+	return tun.events
+}
+
+func (tun *GoTun) Close() error {
+	fmt.Println("Close")
+	// TODO
+//	tun.cancel() 
+	return nil
+}
+
+func CreateGoTun(s *stack.Stack, ch *channel.Endpoint) (wgtun.Device, error) {
+	size := 16
+	ctx, cancel := context.WithCancel(context.Background())
+	tun := &GoTun{
+		ch: ch,
+		events: make(chan wgtun.Event, size),
+		stack: s,
+		ctx: ctx,
+		cancel: cancel,
+	}
+
+//	go func() {
+		fmt.Println("Post event")
+		tun.events <- wgtun.EventUp
+		fmt.Println("Posted event")
+//	}()
+
+	return tun, nil
+}