4 files changed, 27 insertions, 37 deletions
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index e2a2edb2c..41bf9fd9b 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -901,6 +901,14 @@ type NICInfo struct {
 	Context NICContext
 }
 
+// HasNIC returns true if the NICID is defined in the stack.
+func (s *Stack) HasNIC(id tcpip.NICID) bool {
+	s.mu.RLock()
+	_, ok := s.nics[id]
+	s.mu.RUnlock()
+	return ok
+}
+
 // NICInfo returns a map of NICIDs to their associated information.
 func (s *Stack) NICInfo() map[tcpip.NICID]NICInfo {
 	s.mu.RLock()
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index 1eca76c30..72b5ce179 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -552,7 +552,7 @@ type ReusePortOption int
 
 // BindToDeviceOption is used by SetSockOpt/GetSockOpt to specify that sockets
 // should bind only on a specific NIC.
-type BindToDeviceOption string
+type BindToDeviceOption NICID
 
 // QuickAckOption is stubbed out in SetSockOpt/GetSockOpt.
 type QuickAckOption int
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/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index 1a5ee6317..864dc8733 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -631,19 +631,14 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 		e.mu.Unlock()
 
 	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.BroadcastOption:
 		e.mu.Lock()
@@ -767,12 +762,8 @@ 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 = tcpip.BindToDeviceOption("")
+		*o = tcpip.BindToDeviceOption(e.bindToDevice)
+		e.mu.RUnlock()
 		return nil
 
 	case *tcpip.KeepaliveEnabledOption: