Stub out TCP_QUICKACK

PiperOrigin-RevId: 224696233
Change-Id: I45c425d9e32adee5dcce29ca7439a06567b26014

pkg/sentry/socket/epsocket/epsocket.go

@@ -698,6 +698,18 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa
 
 		return int32(v), nil
 
+	case linux.TCP_QUICKACK:
+		if outLen < sizeOfInt32 {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		var v tcpip.QuickAckOption
+		if err := ep.GetSockOpt(&v); err != nil {
+			return nil, syserr.TranslateNetstackError(err)
+		}
+
+		return int32(v), nil
+
 	case linux.TCP_INFO:
 		var v tcpip.TCPInfoOption
 		if err := ep.GetSockOpt(&v); err != nil {
@@ -870,6 +882,14 @@ func setSockOptTCP(t *kernel.Task, ep commonEndpoint, name int, optVal []byte) *
 		v := usermem.ByteOrder.Uint32(optVal)
 		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.CorkOption(v)))
 
+	case linux.TCP_QUICKACK:
+		if len(optVal) < sizeOfInt32 {
+			return syserr.ErrInvalidArgument
+		}
+
+		v := usermem.ByteOrder.Uint32(optVal)
+		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.QuickAckOption(v)))
+
 	case linux.TCP_REPAIR_OPTIONS:
 		t.Kernel().EmitUnimplementedEvent(t)
 

pkg/tcpip/tcpip.go

@@ -436,6 +436,9 @@ type CorkOption int
 // should allow reuse of local address.
 type ReuseAddressOption int
 
+// QuickAckOption is stubbed out in SetSockOpt/GetSockOpt.
+type QuickAckOption int
+
 // PasscredOption is used by SetSockOpt/GetSockOpt to specify whether
 // SCM_CREDENTIALS socket control messages are enabled.
 //

pkg/tcpip/transport/tcp/endpoint.go

@@ -177,6 +177,12 @@ type endpoint struct {
 	// options.
 	reuseAddr bool
 
+	// slowAck holds the negated state of quick ack. It is stubbed out and
+	// does nothing.
+	//
+	// slowAck is a boolean (0 is false) and must be accessed atomically.
+	slowAck uint32
+
 	// segmentQueue is used to hand received segments to the protocol
 	// goroutine. Segments are queued as long as the queue is not full,
 	// and dropped when it is.
@@ -677,6 +683,15 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 		e.mu.Unlock()
 		return nil
 
+	case tcpip.QuickAckOption:
+		if v == 0 {
+			atomic.StoreUint32(&e.slowAck, 1)
+		} else {
+			atomic.StoreUint32(&e.slowAck, 0)
+		}
+
+		return nil
+
 	case tcpip.ReceiveBufferSizeOption:
 		// Make sure the receive buffer size is within the min and max
 		// allowed.
@@ -859,6 +874,13 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		}
 		return nil
 
+	case *tcpip.QuickAckOption:
+		*o = 1
+		if v := atomic.LoadUint32(&e.slowAck); v != 0 {
+			*o = 0
+		}
+		return nil
+
 	case *tcpip.V6OnlyOption:
 		// We only recognize this option on v6 endpoints.
 		if e.netProto != header.IPv6ProtocolNumber {