Add support for tearing down protocol dispatchers and TIME_WAIT endpoints.

Protocol dispatchers were previously leaked. Bypassing TIME_WAIT is required to
test this change.

Also fix a race when a socket in SYN-RCVD is closed. This is also required to
test this change.

PiperOrigin-RevId: 296922548

5 files changed, 52 insertions, 26 deletions

diff --git a/pkg/tcpip/stack/registration.go b/pkg/tcpip/stack/registration.go
index d83adf0ec..f9fd8f18f 100644
--- a/pkg/tcpip/stack/registration.go
+++ b/pkg/tcpip/stack/registration.go
@@ -74,10 +74,11 @@ type TransportEndpoint interface {
 	// HandleControlPacket takes ownership of pkt.
 	HandleControlPacket(id TransportEndpointID, typ ControlType, extra uint32, pkt tcpip.PacketBuffer)
 
-	// Close puts the endpoint in a closed state and frees all resources
-	// associated with it. This cleanup may happen asynchronously. Wait can
-	// be used to block on this asynchronous cleanup.
-	Close()
+	// Abort initiates an expedited endpoint teardown. It puts the endpoint
+	// in a closed state and frees all resources associated with it. This
+	// cleanup may happen asynchronously. Wait can be used to block on this
+	// asynchronous cleanup.
+	Abort()
 
 	// Wait waits for any worker goroutines owned by the endpoint to stop.
 	//
@@ -160,6 +161,13 @@ type TransportProtocol interface {
 	// Option returns an error if the option is not supported or the
 	// provided option value is invalid.
 	Option(option interface{}) *tcpip.Error
+
+	// Close requests that any worker goroutines owned by the protocol
+	// stop.
+	Close()
+
+	// Wait waits for any worker goroutines owned by the protocol to stop.
+	Wait()
 }
 
 // TransportDispatcher contains the methods used by the network stack to deliver
@@ -293,6 +301,13 @@ type NetworkProtocol interface {
 	// Option returns an error if the option is not supported or the
 	// provided option value is invalid.
 	Option(option interface{}) *tcpip.Error
+
+	// Close requests that any worker goroutines owned by the protocol
+	// stop.
+	Close()
+
+	// Wait waits for any worker goroutines owned by the protocol to stop.
+	Wait()
 }
 
 // NetworkDispatcher contains the methods used by the network stack to deliver
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 900dd46c5..ebb6c5e3b 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -1446,7 +1446,13 @@ func (s *Stack) RestoreCleanupEndpoints(es []TransportEndpoint) {
 // Endpoints created or modified during this call may not get closed.
 func (s *Stack) Close() {
 	for _, e := range s.RegisteredEndpoints() {
-		e.Close()
+		e.Abort()
+	}
+	for _, p := range s.transportProtocols {
+		p.proto.Close()
+	}
+	for _, p := range s.networkProtocols {
+		p.Close()
 	}
 }
 
@@ -1464,6 +1470,12 @@ func (s *Stack) Wait() {
 	for _, e := range s.CleanupEndpoints() {
 		e.Wait()
 	}
+	for _, p := range s.transportProtocols {
+		p.proto.Wait()
+	}
+	for _, p := range s.networkProtocols {
+		p.Wait()
+	}
 
 	s.mu.RLock()
 	defer s.mu.RUnlock()
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index 18016e7db..edf6bec52 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -235,6 +235,12 @@ func (f *fakeNetworkProtocol) Option(option interface{}) *tcpip.Error {
 	}
 }
 
+// Close implements TransportProtocol.Close.
+func (*fakeNetworkProtocol) Close() {}
+
+// Wait implements TransportProtocol.Wait.
+func (*fakeNetworkProtocol) Wait() {}
+
 func fakeNetFactory() stack.NetworkProtocol {
 	return &fakeNetworkProtocol{}
 }
diff --git a/pkg/tcpip/stack/transport_demuxer.go b/pkg/tcpip/stack/transport_demuxer.go
index d686e6eb8..778c0a4d6 100644
--- a/pkg/tcpip/stack/transport_demuxer.go
+++ b/pkg/tcpip/stack/transport_demuxer.go
@@ -306,26 +306,6 @@ func (ep *multiPortEndpoint) handlePacketAll(r *Route, id TransportEndpointID, p
 	ep.mu.RUnlock() // Don't use defer for performance reasons.
 }
 
-// Close implements stack.TransportEndpoint.Close.
-func (ep *multiPortEndpoint) Close() {
-	ep.mu.RLock()
-	eps := append([]TransportEndpoint(nil), ep.endpointsArr...)
-	ep.mu.RUnlock()
-	for _, e := range eps {
-		e.Close()
-	}
-}
-
-// Wait implements stack.TransportEndpoint.Wait.
-func (ep *multiPortEndpoint) Wait() {
-	ep.mu.RLock()
-	eps := append([]TransportEndpoint(nil), ep.endpointsArr...)
-	ep.mu.RUnlock()
-	for _, e := range eps {
-		e.Wait()
-	}
-}
-
 // singleRegisterEndpoint tries to add an endpoint to the multiPortEndpoint
 // list. The list might be empty already.
 func (ep *multiPortEndpoint) singleRegisterEndpoint(t TransportEndpoint, reusePort bool) *tcpip.Error {
diff --git a/pkg/tcpip/stack/transport_test.go b/pkg/tcpip/stack/transport_test.go
index 869c69a6d..5d1da2f8b 100644
--- a/pkg/tcpip/stack/transport_test.go
+++ b/pkg/tcpip/stack/transport_test.go
@@ -61,6 +61,10 @@ func newFakeTransportEndpoint(s *stack.Stack, proto *fakeTransportProtocol, netP
 	return &fakeTransportEndpoint{stack: s, TransportEndpointInfo: stack.TransportEndpointInfo{NetProto: netProto}, proto: proto, uniqueID: uniqueID}
 }
 
+func (f *fakeTransportEndpoint) Abort() {
+	f.Close()
+}
+
 func (f *fakeTransportEndpoint) Close() {
 	f.route.Release()
 }
@@ -272,7 +276,7 @@ func (f *fakeTransportProtocol) NewEndpoint(stack *stack.Stack, netProto tcpip.N
 	return newFakeTransportEndpoint(stack, f, netProto, stack.UniqueID()), nil
 }
 
-func (f *fakeTransportProtocol) NewRawEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, _ *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
+func (*fakeTransportProtocol) NewRawEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, _ *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
 	return nil, tcpip.ErrUnknownProtocol
 }
 
@@ -310,6 +314,15 @@ func (f *fakeTransportProtocol) Option(option interface{}) *tcpip.Error {
 	}
 }
 
+// Abort implements TransportProtocol.Abort.
+func (*fakeTransportProtocol) Abort() {}
+
+// Close implements tcpip.Endpoint.Close.
+func (*fakeTransportProtocol) Close() {}
+
+// Wait implements TransportProtocol.Wait.
+func (*fakeTransportProtocol) Wait() {}
+
 func fakeTransFactory() stack.TransportProtocol {
 	return &fakeTransportProtocol{}
 }