net/tcp/setockopt: impelment setsockopt(fd, SOL_TCP, TCP_INQ)

PiperOrigin-RevId: 258859507

6 files changed, 85 insertions, 47 deletions

diff --git a/pkg/tcpip/stack/transport_test.go b/pkg/tcpip/stack/transport_test.go
index 788ffcc8c..b418db046 100644
--- a/pkg/tcpip/stack/transport_test.go
+++ b/pkg/tcpip/stack/transport_test.go
@@ -90,6 +90,11 @@ func (*fakeTransportEndpoint) SetSockOpt(interface{}) *tcpip.Error {
 	return tcpip.ErrInvalidEndpointState
 }
 
+// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
+func (*fakeTransportEndpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+	return -1, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOpt implements tcpip.Endpoint.GetSockOpt.
 func (*fakeTransportEndpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 	switch opt.(type) {
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index c4076666a..c5d79da5e 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -288,6 +288,12 @@ type ControlMessages struct {
 	// Timestamp is the time (in ns) that the last packed used to create
 	// the read data was received.
 	Timestamp int64
+
+	// HasInq indicates whether Inq is valid/set.
+	HasInq bool
+
+	// Inq is the number of bytes ready to be received.
+	Inq int32
 }
 
 // Endpoint is the interface implemented by transport protocols (e.g., tcp, udp)
@@ -383,6 +389,10 @@ type Endpoint interface {
 	// *Option types.
 	GetSockOpt(opt interface{}) *Error
 
+	// GetSockOptInt gets a socket option for simple cases where a return
+	// value has the int type.
+	GetSockOptInt(SockOpt) (int, *Error)
+
 	// State returns a socket's lifecycle state. The returned value is
 	// protocol-specific and is primarily used for diagnostics.
 	State() uint32
@@ -408,6 +418,18 @@ type WriteOptions struct {
 	EndOfRecord bool
 }
 
+// SockOpt represents socket options which values have the int type.
+type SockOpt int
+
+const (
+	// ReceiveQueueSizeOption is used in GetSockOpt to specify that the number of
+	// unread bytes in the input buffer should be returned.
+	ReceiveQueueSizeOption SockOpt = iota
+
+	// TODO(b/137664753): convert all int socket options to be handled via
+	// GetSockOptInt.
+)
+
 // ErrorOption is used in GetSockOpt to specify that the last error reported by
 // the endpoint should be cleared and returned.
 type ErrorOption struct{}
@@ -424,10 +446,6 @@ type ReceiveBufferSizeOption int
 // unread bytes in the output buffer should be returned.
 type SendQueueSizeOption int
 
-// ReceiveQueueSizeOption is used in GetSockOpt to specify that the number of
-// unread bytes in the input buffer should be returned.
-type ReceiveQueueSizeOption int
-
 // V6OnlyOption is used by SetSockOpt/GetSockOpt to specify whether an IPv6
 // socket is to be restricted to sending and receiving IPv6 packets only.
 type V6OnlyOption int
diff --git a/pkg/tcpip/transport/icmp/endpoint.go b/pkg/tcpip/transport/icmp/endpoint.go
index a80ceafd0..ba6671c26 100644
--- a/pkg/tcpip/transport/icmp/endpoint.go
+++ b/pkg/tcpip/transport/icmp/endpoint.go
@@ -314,6 +314,22 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 	return nil
 }
 
+// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
+func (e *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+	switch opt {
+	case tcpip.ReceiveQueueSizeOption:
+		v := 0
+		e.rcvMu.Lock()
+		if !e.rcvList.Empty() {
+			p := e.rcvList.Front()
+			v = p.data.Size()
+		}
+		e.rcvMu.Unlock()
+		return v, nil
+	}
+	return -1, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOpt implements tcpip.Endpoint.GetSockOpt.
 func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 	switch o := opt.(type) {
@@ -332,17 +348,6 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		e.rcvMu.Unlock()
 		return nil
 
-	case *tcpip.ReceiveQueueSizeOption:
-		e.rcvMu.Lock()
-		if e.rcvList.Empty() {
-			*o = 0
-		} else {
-			p := e.rcvList.Front()
-			*o = tcpip.ReceiveQueueSizeOption(p.data.Size())
-		}
-		e.rcvMu.Unlock()
-		return nil
-
 	case *tcpip.KeepaliveEnabledOption:
 		*o = 0
 		return nil
diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index a29587658..b633cd9d8 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -487,6 +487,23 @@ func (ep *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 	return nil
 }
 
+// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
+func (ep *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+	switch opt {
+	case tcpip.ReceiveQueueSizeOption:
+		v := 0
+		ep.rcvMu.Lock()
+		if !ep.rcvList.Empty() {
+			p := ep.rcvList.Front()
+			v = p.data.Size()
+		}
+		ep.rcvMu.Unlock()
+		return v, nil
+	}
+
+	return -1, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOpt implements tcpip.Endpoint.GetSockOpt.
 func (ep *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 	switch o := opt.(type) {
@@ -505,17 +522,6 @@ func (ep *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		ep.rcvMu.Unlock()
 		return nil
 
-	case *tcpip.ReceiveQueueSizeOption:
-		ep.rcvMu.Lock()
-		if ep.rcvList.Empty() {
-			*o = 0
-		} else {
-			p := ep.rcvList.Front()
-			*o = tcpip.ReceiveQueueSizeOption(p.data.Size())
-		}
-		ep.rcvMu.Unlock()
-		return nil
-
 	case *tcpip.KeepaliveEnabledOption:
 		*o = 0
 		return nil
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index beb90afb5..89154391b 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -1100,6 +1100,15 @@ func (e *endpoint) readyReceiveSize() (int, *tcpip.Error) {
 	return e.rcvBufUsed, nil
 }
 
+// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
+func (e *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+	switch opt {
+	case tcpip.ReceiveQueueSizeOption:
+		return e.readyReceiveSize()
+	}
+	return -1, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOpt implements tcpip.Endpoint.GetSockOpt.
 func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 	switch o := opt.(type) {
@@ -1130,15 +1139,6 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		e.rcvListMu.Unlock()
 		return nil
 
-	case *tcpip.ReceiveQueueSizeOption:
-		v, err := e.readyReceiveSize()
-		if err != nil {
-			return err
-		}
-
-		*o = tcpip.ReceiveQueueSizeOption(v)
-		return nil
-
 	case *tcpip.DelayOption:
 		*o = 0
 		if v := atomic.LoadUint32(&e.delay); v != 0 {
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index cb0ea83a6..70f4a2b8c 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -189,7 +189,6 @@ func (e *endpoint) Read(addr *tcpip.FullAddress) (buffer.View, tcpip.ControlMess
 	p := e.rcvList.Front()
 	e.rcvList.Remove(p)
 	e.rcvBufSize -= p.data.Size()
-
 	e.rcvMu.Unlock()
 
 	if addr != nil {
@@ -539,6 +538,22 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 	return nil
 }
 
+// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
+func (e *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+	switch opt {
+	case tcpip.ReceiveQueueSizeOption:
+		v := 0
+		e.rcvMu.Lock()
+		if !e.rcvList.Empty() {
+			p := e.rcvList.Front()
+			v = p.data.Size()
+		}
+		e.rcvMu.Unlock()
+		return v, nil
+	}
+	return -1, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOpt implements tcpip.Endpoint.GetSockOpt.
 func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 	switch o := opt.(type) {
@@ -573,17 +588,6 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		}
 		return nil
 
-	case *tcpip.ReceiveQueueSizeOption:
-		e.rcvMu.Lock()
-		if e.rcvList.Empty() {
-			*o = 0
-		} else {
-			p := e.rcvList.Front()
-			*o = tcpip.ReceiveQueueSizeOption(p.data.Size())
-		}
-		e.rcvMu.Unlock()
-		return nil
-
 	case *tcpip.MulticastTTLOption:
 		e.mu.Lock()
 		*o = tcpip.MulticastTTLOption(e.multicastTTL)