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

1 files changed, 30 insertions, 1 deletions

diff --git a/pkg/tcpip/transport/tcp/dispatcher.go b/pkg/tcpip/transport/tcp/dispatcher.go
index e18012ac0..d792b07d6 100644
--- a/pkg/tcpip/transport/tcp/dispatcher.go
+++ b/pkg/tcpip/transport/tcp/dispatcher.go
@@ -68,17 +68,28 @@ func (q *epQueue) empty() bool {
 type processor struct {
 	epQ              epQueue
 	newEndpointWaker sleep.Waker
+	closeWaker       sleep.Waker
 	id               int
+	wg               sync.WaitGroup
 }
 
 func newProcessor(id int) *processor {
 	p := &processor{
 		id: id,
 	}
+	p.wg.Add(1)
 	go p.handleSegments()
 	return p
 }
 
+func (p *processor) close() {
+	p.closeWaker.Assert()
+}
+
+func (p *processor) wait() {
+	p.wg.Wait()
+}
+
 func (p *processor) queueEndpoint(ep *endpoint) {
 	// Queue an endpoint for processing by the processor goroutine.
 	p.epQ.enqueue(ep)
@@ -87,11 +98,17 @@ func (p *processor) queueEndpoint(ep *endpoint) {
 
 func (p *processor) handleSegments() {
 	const newEndpointWaker = 1
+	const closeWaker = 2
 	s := sleep.Sleeper{}
 	s.AddWaker(&p.newEndpointWaker, newEndpointWaker)
+	s.AddWaker(&p.closeWaker, closeWaker)
 	defer s.Done()
 	for {
-		s.Fetch(true)
+		id, ok := s.Fetch(true)
+		if ok && id == closeWaker {
+			p.wg.Done()
+			return
+		}
 		for ep := p.epQ.dequeue(); ep != nil; ep = p.epQ.dequeue() {
 			if ep.segmentQueue.empty() {
 				continue
@@ -160,6 +177,18 @@ func newDispatcher(nProcessors int) *dispatcher {
 	}
 }
 
+func (d *dispatcher) close() {
+	for _, p := range d.processors {
+		p.close()
+	}
+}
+
+func (d *dispatcher) wait() {
+	for _, p := range d.processors {
+		p.wait()
+	}
+}
+
 func (d *dispatcher) queuePacket(r *stack.Route, stackEP stack.TransportEndpoint, id stack.TransportEndpointID, pkt tcpip.PacketBuffer) {
 	ep := stackEP.(*endpoint)
 	s := newSegment(r, id, pkt)