feat: create NIC

app/tun/handler_tcp.go

@@ -31,7 +31,7 @@ type TCPHandler struct {
 	stack *stack.Stack
 }
 
-func SetTCPHandler(ctx context.Context, dispatcher routing.Dispatcher, policyManager policy.Manager, config *Config) func(*stack.Stack) error {
+func SetTCPHandler(ctx context.Context, dispatcher routing.Dispatcher, policyManager policy.Manager, config *Config) StackOption {
 	return func(s *stack.Stack) error {
 		tcpForwarder := tcp.NewForwarder(s, rcvWnd, maxInFlight, func(r *tcp.ForwarderRequest) {
 			wg := new(waiter.Queue)

app/tun/nic.go

@@ -0,0 +1,19 @@
+package tun
+
+import (
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+)
+
+func CreateNIC(nicID tcpip.NICID, linkEndpoint stack.LinkEndpoint) StackOption {
+	return func(s *stack.Stack) error {
+		if err := s.CreateNICWithOptions(nicID, linkEndpoint,
+			stack.NICOptions{
+				Disabled: false,
+				QDisc:    nil,
+			}); err != nil {
+			return newError("failed to create NIC:", err)
+		}
+		return nil
+	}
+}

app/tun/stack.go

@@ -1,6 +1,7 @@
 package tun
 
 import (
+	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
@@ -11,7 +12,7 @@ import (
 
 type StackOption func(*stack.Stack) error
 
-func (t *TUN) CreateStack(_ stack.LinkEndpoint) (*stack.Stack, error) {
+func (t *TUN) CreateStack(linkedEndpoint stack.LinkEndpoint) (*stack.Stack, error) {
 	s := stack.New(stack.Options{
 		NetworkProtocols: []stack.NetworkProtocolFactory{
 			ipv4.NewProtocol,
@@ -25,8 +26,12 @@ func (t *TUN) CreateStack(_ stack.LinkEndpoint) (*stack.Stack, error) {
 		},
 	})
 
+	nicID := tcpip.NICID(s.UniqueID())
+
 	opts := []StackOption{
 		SetTCPHandler(t.ctx, t.dispatcher, t.policyManager, t.config),
+
+		CreateNIC(nicID, linkedEndpoint),
 	}
 
 	for _, opt := range opts {
@@ -35,7 +40,5 @@ func (t *TUN) CreateStack(_ stack.LinkEndpoint) (*stack.Stack, error) {
 		}
 	}
 
-	// nicID := tcpip.NICID(s.UniqueID())
-
 	return s, nil
 }