Change BindToDeviceOption to store NICID

This makes it possible to call the sockopt from go even when the NIC has no
name.

PiperOrigin-RevId: 288955236

2 files changed, 27 insertions, 42 deletions

diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 2ac1b6877..920b24975 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -1279,19 +1279,14 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 		return nil
 
 	case tcpip.BindToDeviceOption:
-		e.mu.Lock()
-		defer e.mu.Unlock()
-		if v == "" {
-			e.bindToDevice = 0
-			return nil
-		}
-		for nicID, nic := range e.stack.NICInfo() {
-			if nic.Name == string(v) {
-				e.bindToDevice = nicID
-				return nil
-			}
+		id := tcpip.NICID(v)
+		if id != 0 && !e.stack.HasNIC(id) {
+			return tcpip.ErrUnknownDevice
 		}
-		return tcpip.ErrUnknownDevice
+		e.mu.Lock()
+		e.bindToDevice = id
+		e.mu.Unlock()
+		return nil
 
 	case tcpip.QuickAckOption:
 		if v == 0 {
@@ -1550,12 +1545,8 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 
 	case *tcpip.BindToDeviceOption:
 		e.mu.RLock()
-		defer e.mu.RUnlock()
-		if nic, ok := e.stack.NICInfo()[e.bindToDevice]; ok {
-			*o = tcpip.BindToDeviceOption(nic.Name)
-			return nil
-		}
-		*o = ""
+		*o = tcpip.BindToDeviceOption(e.bindToDevice)
+		e.mu.RUnlock()
 		return nil
 
 	case *tcpip.QuickAckOption:
diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go
index 15745ebd4..1aa0733d0 100644
--- a/pkg/tcpip/transport/tcp/tcp_test.go
+++ b/pkg/tcpip/transport/tcp/tcp_test.go
@@ -1083,12 +1083,12 @@ func TestTrafficClassV6(t *testing.T) {
 func TestConnectBindToDevice(t *testing.T) {
 	for _, test := range []struct {
 		name   string
-		device string
+		device tcpip.NICID
 		want   tcp.EndpointState
 	}{
-		{"RightDevice", "nic1", tcp.StateEstablished},
-		{"WrongDevice", "nic2", tcp.StateSynSent},
-		{"AnyDevice", "", tcp.StateEstablished},
+		{"RightDevice", 1, tcp.StateEstablished},
+		{"WrongDevice", 2, tcp.StateSynSent},
+		{"AnyDevice", 0, tcp.StateEstablished},
 	} {
 		t.Run(test.name, func(t *testing.T) {
 			c := context.New(t, defaultMTU)
@@ -3794,47 +3794,41 @@ func TestBindToDeviceOption(t *testing.T) {
 	}
 	defer ep.Close()
 
-	opts := stack.NICOptions{Name: "my_device"}
-	if err := s.CreateNICWithOptions(321, loopback.New(), opts); err != nil {
-		t.Errorf("CreateNICWithOptions(_, _, %+v) failed: %v", opts, err)
-	}
-
-	// Make an nameless NIC.
-	if err := s.CreateNIC(54321, loopback.New()); err != nil {
+	if err := s.CreateNIC(321, loopback.New()); err != nil {
 		t.Errorf("CreateNIC failed: %v", err)
 	}
 
-	// strPtr is used instead of taking the address of string literals, which is
+	// nicIDPtr is used instead of taking the address of NICID literals, which is
 	// a compiler error.
-	strPtr := func(s string) *string {
+	nicIDPtr := func(s tcpip.NICID) *tcpip.NICID {
 		return &s
 	}
 
 	testActions := []struct {
 		name                 string
-		setBindToDevice      *string
+		setBindToDevice      *tcpip.NICID
 		setBindToDeviceError *tcpip.Error
 		getBindToDevice      tcpip.BindToDeviceOption
 	}{
-		{"GetDefaultValue", nil, nil, ""},
-		{"BindToNonExistent", strPtr("non_existent_device"), tcpip.ErrUnknownDevice, ""},
-		{"BindToExistent", strPtr("my_device"), nil, "my_device"},
-		{"UnbindToDevice", strPtr(""), nil, ""},
+		{"GetDefaultValue", nil, nil, 0},
+		{"BindToNonExistent", nicIDPtr(999), tcpip.ErrUnknownDevice, 0},
+		{"BindToExistent", nicIDPtr(321), nil, 321},
+		{"UnbindToDevice", nicIDPtr(0), nil, 0},
 	}
 	for _, testAction := range testActions {
 		t.Run(testAction.name, func(t *testing.T) {
 			if testAction.setBindToDevice != nil {
 				bindToDevice := tcpip.BindToDeviceOption(*testAction.setBindToDevice)
-				if got, want := ep.SetSockOpt(bindToDevice), testAction.setBindToDeviceError; got != want {
-					t.Errorf("SetSockOpt(%v) got %v, want %v", bindToDevice, got, want)
+				if gotErr, wantErr := ep.SetSockOpt(bindToDevice), testAction.setBindToDeviceError; gotErr != wantErr {
+					t.Errorf("SetSockOpt(%v) got %v, want %v", bindToDevice, gotErr, wantErr)
 				}
 			}
-			bindToDevice := tcpip.BindToDeviceOption("to be modified by GetSockOpt")
-			if ep.GetSockOpt(&bindToDevice) != nil {
-				t.Errorf("GetSockOpt got %v, want %v", ep.GetSockOpt(&bindToDevice), nil)
+			bindToDevice := tcpip.BindToDeviceOption(88888)
+			if err := ep.GetSockOpt(&bindToDevice); err != nil {
+				t.Errorf("GetSockOpt got %v, want %v", err, nil)
 			}
 			if got, want := bindToDevice, testAction.getBindToDevice; got != want {
-				t.Errorf("bindToDevice got %q, want %q", got, want)
+				t.Errorf("bindToDevice got %d, want %d", got, want)
 			}
 		})
 	}