Remove reundant global tcpip.LinkEndpointID.

PiperOrigin-RevId: 267709597

pkg/tcpip/link/channel/channel.go

@@ -44,14 +44,12 @@ type Endpoint struct {
 }
 
 // New creates a new channel endpoint.
-func New(size int, mtu uint32, linkAddr tcpip.LinkAddress) (tcpip.LinkEndpointID, *Endpoint) {
-	e := &Endpoint{
+func New(size int, mtu uint32, linkAddr tcpip.LinkAddress) *Endpoint {
+	return &Endpoint{
 		C:        make(chan PacketInfo, size),
 		mtu:      mtu,
 		linkAddr: linkAddr,
 	}
-
-	return stack.RegisterLinkEndpoint(e), e
 }
 
 // Drain removes all outbound packets from the channel and counts them.

pkg/tcpip/link/fdbased/endpoint.go

@@ -165,7 +165,7 @@ type Options struct {
 //
 // Makes fd non-blocking, but does not take ownership of fd, which must remain
 // open for the lifetime of the returned endpoint.
-func New(opts *Options) (tcpip.LinkEndpointID, error) {
+func New(opts *Options) (stack.LinkEndpoint, error) {
 	caps := stack.LinkEndpointCapabilities(0)
 	if opts.RXChecksumOffload {
 		caps |= stack.CapabilityRXChecksumOffload
@@ -190,7 +190,7 @@ func New(opts *Options) (tcpip.LinkEndpointID, error) {
 	}
 
 	if len(opts.FDs) == 0 {
-		return 0, fmt.Errorf("opts.FD is empty, at least one FD must be specified")
+		return nil, fmt.Errorf("opts.FD is empty, at least one FD must be specified")
 	}
 
 	e := &endpoint{
@@ -207,12 +207,12 @@ func New(opts *Options) (tcpip.LinkEndpointID, error) {
 	for i := 0; i < len(e.fds); i++ {
 		fd := e.fds[i]
 		if err := syscall.SetNonblock(fd, true); err != nil {
-			return 0, fmt.Errorf("syscall.SetNonblock(%v) failed: %v", fd, err)
+			return nil, fmt.Errorf("syscall.SetNonblock(%v) failed: %v", fd, err)
 		}
 
 		isSocket, err := isSocketFD(fd)
 		if err != nil {
-			return 0, err
+			return nil, err
 		}
 		if isSocket {
 			if opts.GSOMaxSize != 0 {
@@ -222,12 +222,12 @@ func New(opts *Options) (tcpip.LinkEndpointID, error) {
 		}
 		inboundDispatcher, err := createInboundDispatcher(e, fd, isSocket)
 		if err != nil {
-			return 0, fmt.Errorf("createInboundDispatcher(...) = %v", err)
+			return nil, fmt.Errorf("createInboundDispatcher(...) = %v", err)
 		}
 		e.inboundDispatchers = append(e.inboundDispatchers, inboundDispatcher)
 	}
 
-	return stack.RegisterLinkEndpoint(e), nil
+	return e, nil
 }
 
 func createInboundDispatcher(e *endpoint, fd int, isSocket bool) (linkDispatcher, error) {
@@ -435,14 +435,12 @@ func (e *InjectableEndpoint) Inject(protocol tcpip.NetworkProtocolNumber, vv buf
 }
 
 // NewInjectable creates a new fd-based InjectableEndpoint.
-func NewInjectable(fd int, mtu uint32, capabilities stack.LinkEndpointCapabilities) (tcpip.LinkEndpointID, *InjectableEndpoint) {
+func NewInjectable(fd int, mtu uint32, capabilities stack.LinkEndpointCapabilities) *InjectableEndpoint {
 	syscall.SetNonblock(fd, true)
 
-	e := &InjectableEndpoint{endpoint: endpoint{
+	return &InjectableEndpoint{endpoint: endpoint{
 		fds:  []int{fd},
 		mtu:  mtu,
 		caps: capabilities,
 	}}
-
-	return stack.RegisterLinkEndpoint(e), e
 }

pkg/tcpip/link/fdbased/endpoint_test.go

@@ -68,11 +68,10 @@ func newContext(t *testing.T, opt *Options) *context {
 	}
 
 	opt.FDs = []int{fds[1]}
-	epID, err := New(opt)
+	ep, err := New(opt)
 	if err != nil {
 		t.Fatalf("Failed to create FD endpoint: %v", err)
 	}
-	ep := stack.FindLinkEndpoint(epID).(*endpoint)
 
 	c := &context{
 		t:    t,

pkg/tcpip/link/loopback/loopback.go

@@ -32,8 +32,8 @@ type endpoint struct {
 
 // New creates a new loopback endpoint. This link-layer endpoint just turns
 // outbound packets into inbound packets.
-func New() tcpip.LinkEndpointID {
-	return stack.RegisterLinkEndpoint(&endpoint{})
+func New() stack.LinkEndpoint {
+	return &endpoint{}
 }
 
 // Attach implements stack.LinkEndpoint.Attach. It just saves the stack network-

pkg/tcpip/link/muxed/injectable.go

@@ -105,9 +105,8 @@ func (m *InjectableEndpoint) WriteRawPacket(dest tcpip.Address, packet []byte) *
 }
 
 // NewInjectableEndpoint creates a new multi-endpoint injectable endpoint.
-func NewInjectableEndpoint(routes map[tcpip.Address]stack.InjectableLinkEndpoint) (tcpip.LinkEndpointID, *InjectableEndpoint) {
-	e := &InjectableEndpoint{
+func NewInjectableEndpoint(routes map[tcpip.Address]stack.InjectableLinkEndpoint) *InjectableEndpoint {
+	return &InjectableEndpoint{
 		routes: routes,
 	}
-	return stack.RegisterLinkEndpoint(e), e
 }

pkg/tcpip/link/muxed/injectable_test.go

@@ -87,8 +87,8 @@ func makeTestInjectableEndpoint(t *testing.T) (*InjectableEndpoint, *os.File, tc
 	if err != nil {
 		t.Fatal("Failed to create socket pair:", err)
 	}
-	_, underlyingEndpoint := fdbased.NewInjectable(pair[1], 6500, stack.CapabilityNone)
+	underlyingEndpoint := fdbased.NewInjectable(pair[1], 6500, stack.CapabilityNone)
 	routes := map[tcpip.Address]stack.InjectableLinkEndpoint{dstIP: underlyingEndpoint}
-	_, endpoint := NewInjectableEndpoint(routes)
+	endpoint := NewInjectableEndpoint(routes)
 	return endpoint, os.NewFile(uintptr(pair[0]), "test route end"), dstIP
 }

pkg/tcpip/link/sharedmem/sharedmem.go

@@ -94,7 +94,7 @@ type endpoint struct {
 
 // New creates a new shared-memory-based endpoint. Buffers will be broken up
 // into buffers of "bufferSize" bytes.
-func New(mtu, bufferSize uint32, addr tcpip.LinkAddress, tx, rx QueueConfig) (tcpip.LinkEndpointID, error) {
+func New(mtu, bufferSize uint32, addr tcpip.LinkAddress, tx, rx QueueConfig) (stack.LinkEndpoint, error) {
 	e := &endpoint{
 		mtu:        mtu,
 		bufferSize: bufferSize,
@@ -102,15 +102,15 @@ func New(mtu, bufferSize uint32, addr tcpip.LinkAddress, tx, rx QueueConfig) (tc
 	}
 
 	if err := e.tx.init(bufferSize, &tx); err != nil {
-		return 0, err
+		return nil, err
 	}
 
 	if err := e.rx.init(bufferSize, &rx); err != nil {
 		e.tx.cleanup()
-		return 0, err
+		return nil, err
 	}
 
-	return stack.RegisterLinkEndpoint(e), nil
+	return e, nil
 }
 
 // Close frees all resources associated with the endpoint.

pkg/tcpip/link/sharedmem/sharedmem_test.go

@@ -119,12 +119,12 @@ func newTestContext(t *testing.T, mtu, bufferSize uint32, addr tcpip.LinkAddress
 	initQueue(t, &c.txq, &c.txCfg)
 	initQueue(t, &c.rxq, &c.rxCfg)
 
-	id, err := New(mtu, bufferSize, addr, c.txCfg, c.rxCfg)
+	ep, err := New(mtu, bufferSize, addr, c.txCfg, c.rxCfg)
 	if err != nil {
 		t.Fatalf("New failed: %v", err)
 	}
 
-	c.ep = stack.FindLinkEndpoint(id).(*endpoint)
+	c.ep = ep.(*endpoint)
 	c.ep.Attach(c)
 
 	return c

pkg/tcpip/link/sniffer/sniffer.go

@@ -58,10 +58,10 @@ type endpoint struct {
 
 // New creates a new sniffer link-layer endpoint. It wraps around another
 // endpoint and logs packets and they traverse the endpoint.
-func New(lower tcpip.LinkEndpointID) tcpip.LinkEndpointID {
-	return stack.RegisterLinkEndpoint(&endpoint{
-		lower: stack.FindLinkEndpoint(lower),
-	})
+func New(lower stack.LinkEndpoint) stack.LinkEndpoint {
+	return &endpoint{
+		lower: lower,
+	}
 }
 
 func zoneOffset() (int32, error) {
@@ -102,15 +102,15 @@ func writePCAPHeader(w io.Writer, maxLen uint32) error {
 // snapLen is the maximum amount of a packet to be saved. Packets with a length
 // less than or equal too snapLen will be saved in their entirety. Longer
 // packets will be truncated to snapLen.
-func NewWithFile(lower tcpip.LinkEndpointID, file *os.File, snapLen uint32) (tcpip.LinkEndpointID, error) {
+func NewWithFile(lower stack.LinkEndpoint, file *os.File, snapLen uint32) (stack.LinkEndpoint, error) {
 	if err := writePCAPHeader(file, snapLen); err != nil {
-		return 0, err
+		return nil, err
 	}
-	return stack.RegisterLinkEndpoint(&endpoint{
-		lower:      stack.FindLinkEndpoint(lower),
+	return &endpoint{
+		lower:      lower,
 		file:       file,
 		maxPCAPLen: snapLen,
-	}), nil
+	}, nil
 }
 
 // DeliverNetworkPacket implements the stack.NetworkDispatcher interface. It is

pkg/tcpip/link/waitable/waitable.go

@@ -40,11 +40,10 @@ type Endpoint struct {
 // New creates a new waitable link-layer endpoint. It wraps around another
 // endpoint and allows the caller to block new write/dispatch calls and wait for
 // the inflight ones to finish before returning.
-func New(lower tcpip.LinkEndpointID) (tcpip.LinkEndpointID, *Endpoint) {
-	e := &Endpoint{
-		lower: stack.FindLinkEndpoint(lower),
+func New(lower stack.LinkEndpoint) *Endpoint {
+	return &Endpoint{
+		lower: lower,
 	}
-	return stack.RegisterLinkEndpoint(e), e
 }
 
 // DeliverNetworkPacket implements stack.NetworkDispatcher.DeliverNetworkPacket.

pkg/tcpip/link/waitable/waitable_test.go

@@ -72,7 +72,7 @@ func (e *countedEndpoint) WritePacket(r *stack.Route, _ *stack.GSO, hdr buffer.P
 
 func TestWaitWrite(t *testing.T) {
 	ep := &countedEndpoint{}
-	_, wep := New(stack.RegisterLinkEndpoint(ep))
+	wep := New(ep)
 
 	// Write and check that it goes through.
 	wep.WritePacket(nil, nil /* gso */, buffer.Prependable{}, buffer.VectorisedView{}, 0)
@@ -97,7 +97,7 @@ func TestWaitWrite(t *testing.T) {
 
 func TestWaitDispatch(t *testing.T) {
 	ep := &countedEndpoint{}
-	_, wep := New(stack.RegisterLinkEndpoint(ep))
+	wep := New(ep)
 
 	// Check that attach happens.
 	wep.Attach(ep)
@@ -139,7 +139,7 @@ func TestOtherMethods(t *testing.T) {
 		hdrLen:       hdrLen,
 		linkAddr:     linkAddr,
 	}
-	_, wep := New(stack.RegisterLinkEndpoint(ep))
+	wep := New(ep)
 
 	if v := wep.MTU(); v != mtu {
 		t.Fatalf("Unexpected mtu: got=%v, want=%v", v, mtu)

pkg/tcpip/network/arp/arp_test.go

@@ -47,11 +47,13 @@ func newTestContext(t *testing.T) *testContext {
 	s := stack.New([]string{ipv4.ProtocolName, arp.ProtocolName}, []string{icmp.ProtocolName4}, stack.Options{})
 
 	const defaultMTU = 65536
-	id, linkEP := channel.New(256, defaultMTU, stackLinkAddr)
+	ep := channel.New(256, defaultMTU, stackLinkAddr)
+	wep := stack.LinkEndpoint(ep)
+
 	if testing.Verbose() {
-		id = sniffer.New(id)
+		wep = sniffer.New(ep)
 	}
-	if err := s.CreateNIC(1, id); err != nil {
+	if err := s.CreateNIC(1, wep); err != nil {
 		t.Fatalf("CreateNIC failed: %v", err)
 	}
 
@@ -73,7 +75,7 @@ func newTestContext(t *testing.T) *testContext {
 	return &testContext{
 		t:      t,
 		s:      s,
-		linkEP: linkEP,
+		linkEP: ep,
 	}
 }
 

pkg/tcpip/network/ipv4/ipv4_test.go

@@ -36,11 +36,11 @@ func TestExcludeBroadcast(t *testing.T) {
 	s := stack.New([]string{ipv4.ProtocolName}, []string{udp.ProtocolName}, stack.Options{})
 
 	const defaultMTU = 65536
-	id, _ := channel.New(256, defaultMTU, "")
+	ep := stack.LinkEndpoint(channel.New(256, defaultMTU, ""))
 	if testing.Verbose() {
-		id = sniffer.New(id)
+		ep = sniffer.New(ep)
 	}
-	if err := s.CreateNIC(1, id); err != nil {
+	if err := s.CreateNIC(1, ep); err != nil {
 		t.Fatalf("CreateNIC failed: %v", err)
 	}
 
@@ -184,15 +184,12 @@ type errorChannel struct {
 // newErrorChannel creates a new errorChannel endpoint. Each call to WritePacket
 // will return successive errors from packetCollectorErrors until the list is
 // empty and then return nil each time.
-func newErrorChannel(size int, mtu uint32, linkAddr tcpip.LinkAddress, packetCollectorErrors []*tcpip.Error) (tcpip.LinkEndpointID, *errorChannel) {
-	_, e := channel.New(size, mtu, linkAddr)
-	ec := errorChannel{
-		Endpoint:              e,
+func newErrorChannel(size int, mtu uint32, linkAddr tcpip.LinkAddress, packetCollectorErrors []*tcpip.Error) *errorChannel {
+	return &errorChannel{
+		Endpoint:              channel.New(size, mtu, linkAddr),
 		Ch:                    make(chan packetInfo, size),
 		packetCollectorErrors: packetCollectorErrors,
 	}
-
-	return stack.RegisterLinkEndpoint(e), &ec
 }
 
 // packetInfo holds all the information about an outbound packet.
@@ -242,9 +239,8 @@ type context struct {
 func buildContext(t *testing.T, packetCollectorErrors []*tcpip.Error, mtu uint32) context {
 	// Make the packet and write it.
 	s := stack.New([]string{ipv4.ProtocolName}, []string{}, stack.Options{})
-	_, linkEP := newErrorChannel(100 /* Enough for all tests. */, mtu, "", packetCollectorErrors)
-	linkEPId := stack.RegisterLinkEndpoint(linkEP)
-	s.CreateNIC(1, linkEPId)
+	ep := newErrorChannel(100 /* Enough for all tests. */, mtu, "", packetCollectorErrors)
+	s.CreateNIC(1, ep)
 	const (
 		src = "\x10\x00\x00\x01"
 		dst = "\x10\x00\x00\x02"
@@ -266,7 +262,7 @@ func buildContext(t *testing.T, packetCollectorErrors []*tcpip.Error, mtu uint32
 	}
 	return context{
 		Route:  r,
-		linkEP: linkEP,
+		linkEP: ep,
 	}
 }
 

pkg/tcpip/network/ipv6/icmp_test.go

@@ -83,8 +83,7 @@ func (*stubLinkAddressCache) AddLinkAddress(tcpip.NICID, tcpip.Address, tcpip.Li
 func TestICMPCounts(t *testing.T) {
 	s := stack.New([]string{ProtocolName}, []string{icmp.ProtocolName6}, stack.Options{})
 	{
-		id := stack.RegisterLinkEndpoint(&stubLinkEndpoint{})
-		if err := s.CreateNIC(1, id); err != nil {
+		if err := s.CreateNIC(1, &stubLinkEndpoint{}); err != nil {
 			t.Fatalf("CreateNIC(_) = %s", err)
 		}
 		if err := s.AddAddress(1, ProtocolNumber, lladdr0); err != nil {
@@ -211,14 +210,13 @@ func newTestContext(t *testing.T) *testContext {
 	}
 
 	const defaultMTU = 65536
-	_, linkEP0 := channel.New(256, defaultMTU, linkAddr0)
-	c.linkEP0 = linkEP0
-	wrappedEP0 := endpointWithResolutionCapability{LinkEndpoint: linkEP0}
-	id0 := stack.RegisterLinkEndpoint(wrappedEP0)
+	c.linkEP0 = channel.New(256, defaultMTU, linkAddr0)
+
+	wrappedEP0 := stack.LinkEndpoint(endpointWithResolutionCapability{LinkEndpoint: c.linkEP0})
 	if testing.Verbose() {
-		id0 = sniffer.New(id0)
+		wrappedEP0 = sniffer.New(wrappedEP0)
 	}
-	if err := c.s0.CreateNIC(1, id0); err != nil {
+	if err := c.s0.CreateNIC(1, wrappedEP0); err != nil {
 		t.Fatalf("CreateNIC s0: %v", err)
 	}
 	if err := c.s0.AddAddress(1, ProtocolNumber, lladdr0); err != nil {
@@ -228,11 +226,9 @@ func newTestContext(t *testing.T) *testContext {
 		t.Fatalf("AddAddress sn lladdr0: %v", err)
 	}
 
-	_, linkEP1 := channel.New(256, defaultMTU, linkAddr1)
-	c.linkEP1 = linkEP1
-	wrappedEP1 := endpointWithResolutionCapability{LinkEndpoint: linkEP1}
-	id1 := stack.RegisterLinkEndpoint(wrappedEP1)
-	if err := c.s1.CreateNIC(1, id1); err != nil {
+	c.linkEP1 = channel.New(256, defaultMTU, linkAddr1)
+	wrappedEP1 := stack.LinkEndpoint(endpointWithResolutionCapability{LinkEndpoint: c.linkEP1})
+	if err := c.s1.CreateNIC(1, wrappedEP1); err != nil {
 		t.Fatalf("CreateNIC failed: %v", err)
 	}
 	if err := c.s1.AddAddress(1, ProtocolNumber, lladdr1); err != nil {

pkg/tcpip/network/ipv6/ndp_test.go

@@ -32,15 +32,14 @@ func setupStackAndEndpoint(t *testing.T, llladdr, rlladdr tcpip.Address) (*stack
 	t.Helper()
 
 	s := stack.New([]string{ProtocolName}, []string{icmp.ProtocolName6}, stack.Options{})
-	{
-		id := stack.RegisterLinkEndpoint(&stubLinkEndpoint{})
-		if err := s.CreateNIC(1, id); err != nil {
-			t.Fatalf("CreateNIC(_) = %s", err)
-		}
-		if err := s.AddAddress(1, ProtocolNumber, llladdr); err != nil {
-			t.Fatalf("AddAddress(_, %d, %s) = %s", ProtocolNumber, llladdr, err)
-		}
+
+	if err := s.CreateNIC(1, &stubLinkEndpoint{}); err != nil {
+		t.Fatalf("CreateNIC(_) = %s", err)
 	}
+	if err := s.AddAddress(1, ProtocolNumber, llladdr); err != nil {
+		t.Fatalf("AddAddress(_, %d, %s) = %s", ProtocolNumber, llladdr, err)
+	}
+
 	{
 		subnet, err := tcpip.NewSubnet(rlladdr, tcpip.AddressMask(strings.Repeat("\xff", len(rlladdr))))
 		if err != nil {

pkg/tcpip/stack/registration.go

@@ -15,8 +15,6 @@
 package stack
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/sleep"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
@@ -379,10 +377,6 @@ var (
 	networkProtocols   = make(map[string]NetworkProtocolFactory)
 
 	unassociatedFactory UnassociatedEndpointFactory
-
-	linkEPMu           sync.RWMutex
-	nextLinkEndpointID tcpip.LinkEndpointID = 1
-	linkEndpoints                           = make(map[tcpip.LinkEndpointID]LinkEndpoint)
 )
 
 // RegisterTransportProtocolFactory registers a new transport protocol factory
@@ -406,28 +400,6 @@ func RegisterUnassociatedFactory(f UnassociatedEndpointFactory) {
 	unassociatedFactory = f
 }
 
-// RegisterLinkEndpoint register a link-layer protocol endpoint and returns an
-// ID that can be used to refer to it.
-func RegisterLinkEndpoint(linkEP LinkEndpoint) tcpip.LinkEndpointID {
-	linkEPMu.Lock()
-	defer linkEPMu.Unlock()
-
-	v := nextLinkEndpointID
-	nextLinkEndpointID++
-
-	linkEndpoints[v] = linkEP
-
-	return v
-}
-
-// FindLinkEndpoint finds the link endpoint associated with the given ID.
-func FindLinkEndpoint(id tcpip.LinkEndpointID) LinkEndpoint {
-	linkEPMu.RLock()
-	defer linkEPMu.RUnlock()
-
-	return linkEndpoints[id]
-}
-
 // GSOType is the type of GSO segments.
 //
 // +stateify savable

pkg/tcpip/stack/stack.go

@@ -620,12 +620,7 @@ func (s *Stack) NewRawEndpoint(transport tcpip.TransportProtocolNumber, network
 
 // createNIC creates a NIC with the provided id and link-layer endpoint, and
 // optionally enable it.
-func (s *Stack) createNIC(id tcpip.NICID, name string, linkEP tcpip.LinkEndpointID, enabled, loopback bool) *tcpip.Error {
-	ep := FindLinkEndpoint(linkEP)
-	if ep == nil {
-		return tcpip.ErrBadLinkEndpoint
-	}
-
+func (s *Stack) createNIC(id tcpip.NICID, name string, ep LinkEndpoint, enabled, loopback bool) *tcpip.Error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
@@ -645,33 +640,33 @@ func (s *Stack) createNIC(id tcpip.NICID, name string, linkEP tcpip.LinkEndpoint
 }
 
 // CreateNIC creates a NIC with the provided id and link-layer endpoint.
-func (s *Stack) CreateNIC(id tcpip.NICID, linkEP tcpip.LinkEndpointID) *tcpip.Error {
-	return s.createNIC(id, "", linkEP, true, false)
+func (s *Stack) CreateNIC(id tcpip.NICID, ep LinkEndpoint) *tcpip.Error {
+	return s.createNIC(id, "", ep, true, false)
 }
 
 // CreateNamedNIC creates a NIC with the provided id and link-layer endpoint,
 // and a human-readable name.
-func (s *Stack) CreateNamedNIC(id tcpip.NICID, name string, linkEP tcpip.LinkEndpointID) *tcpip.Error {
-	return s.createNIC(id, name, linkEP, true, false)
+func (s *Stack) CreateNamedNIC(id tcpip.NICID, name string, ep LinkEndpoint) *tcpip.Error {
+	return s.createNIC(id, name, ep, true, false)
 }
 
 // CreateNamedLoopbackNIC creates a NIC with the provided id and link-layer
 // endpoint, and a human-readable name.
-func (s *Stack) CreateNamedLoopbackNIC(id tcpip.NICID, name string, linkEP tcpip.LinkEndpointID) *tcpip.Error {
-	return s.createNIC(id, name, linkEP, true, true)
+func (s *Stack) CreateNamedLoopbackNIC(id tcpip.NICID, name string, ep LinkEndpoint) *tcpip.Error {
+	return s.createNIC(id, name, ep, true, true)
 }
 
 // CreateDisabledNIC creates a NIC with the provided id and link-layer endpoint,
 // but leave it disable. Stack.EnableNIC must be called before the link-layer
 // endpoint starts delivering packets to it.
-func (s *Stack) CreateDisabledNIC(id tcpip.NICID, linkEP tcpip.LinkEndpointID) *tcpip.Error {
-	return s.createNIC(id, "", linkEP, false, false)
+func (s *Stack) CreateDisabledNIC(id tcpip.NICID, ep LinkEndpoint) *tcpip.Error {
+	return s.createNIC(id, "", ep, false, false)
 }
 
 // CreateDisabledNamedNIC is a combination of CreateNamedNIC and
 // CreateDisabledNIC.
-func (s *Stack) CreateDisabledNamedNIC(id tcpip.NICID, name string, linkEP tcpip.LinkEndpointID) *tcpip.Error {
-	return s.createNIC(id, name, linkEP, false, false)
+func (s *Stack) CreateDisabledNamedNIC(id tcpip.NICID, name string, ep LinkEndpoint) *tcpip.Error {
+	return s.createNIC(id, name, ep, false, false)
 }
 
 // EnableNIC enables the given NIC so that the link-layer endpoint can start

pkg/tcpip/stack/transport_test.go

@@ -278,9 +278,9 @@ func (f *fakeTransportProtocol) Option(option interface{}) *tcpip.Error {
 }
 
 func TestTransportReceive(t *testing.T) {
-	id, linkEP := channel.New(10, defaultMTU, "")
+	linkEP := channel.New(10, defaultMTU, "")
 	s := stack.New([]string{"fakeNet"}, []string{"fakeTrans"}, stack.Options{})
-	if err := s.CreateNIC(1, id); err != nil {
+	if err := s.CreateNIC(1, linkEP); err != nil {
 		t.Fatalf("CreateNIC failed: %v", err)
 	}
 
@@ -340,9 +340,9 @@ func TestTransportReceive(t *testing.T) {
 }
 
 func TestTransportControlReceive(t *testing.T) {
-	id, linkEP := channel.New(10, defaultMTU, "")
+	linkEP := channel.New(10, defaultMTU, "")
 	s := stack.New([]string{"fakeNet"}, []string{"fakeTrans"}, stack.Options{})
-	if err := s.CreateNIC(1, id); err != nil {
+	if err := s.CreateNIC(1, linkEP); err != nil {
 		t.Fatalf("CreateNIC failed: %v", err)
 	}
 
@@ -408,9 +408,9 @@ func TestTransportControlReceive(t *testing.T) {
 }
 
 func TestTransportSend(t *testing.T) {
-	id, _ := channel.New(10, defaultMTU, "")
+	linkEP := channel.New(10, defaultMTU, "")
 	s := stack.New([]string{"fakeNet"}, []string{"fakeTrans"}, stack.Options{})
-	if err := s.CreateNIC(1, id); err != nil {
+	if err := s.CreateNIC(1, linkEP); err != nil {
 		t.Fatalf("CreateNIC failed: %v", err)
 	}
 
@@ -497,16 +497,16 @@ func TestTransportForwarding(t *testing.T) {
 	s.SetForwarding(true)
 
 	// TODO(b/123449044): Change this to a channel NIC.
-	id1 := loopback.New()
-	if err := s.CreateNIC(1, id1); err != nil {
+	ep1 := loopback.New()
+	if err := s.CreateNIC(1, ep1); err != nil {
 		t.Fatalf("CreateNIC #1 failed: %v", err)
 	}
 	if err := s.AddAddress(1, fakeNetNumber, "\x01"); err != nil {
 		t.Fatalf("AddAddress #1 failed: %v", err)
 	}
 
-	id2, linkEP2 := channel.New(10, defaultMTU, "")
-	if err := s.CreateNIC(2, id2); err != nil {
+	ep2 := channel.New(10, defaultMTU, "")
+	if err := s.CreateNIC(2, ep2); err != nil {
 		t.Fatalf("CreateNIC #2 failed: %v", err)
 	}
 	if err := s.AddAddress(2, fakeNetNumber, "\x02"); err != nil {
@@ -545,7 +545,7 @@ func TestTransportForwarding(t *testing.T) {
 	req[0] = 1
 	req[1] = 3
 	req[2] = byte(fakeTransNumber)
-	linkEP2.Inject(fakeNetNumber, req.ToVectorisedView())
+	ep2.Inject(fakeNetNumber, req.ToVectorisedView())
 
 	aep, _, err := ep.Accept()
 	if err != nil || aep == nil {
@@ -559,7 +559,7 @@ func TestTransportForwarding(t *testing.T) {
 
 	var p channel.PacketInfo
 	select {
-	case p = <-linkEP2.C:
+	case p = <-ep2.C:
 	default:
 		t.Fatal("Response packet not forwarded")
 	}

pkg/tcpip/tcpip.go

@@ -600,9 +600,6 @@ func (r Route) String() string {
 	return out.String()
 }
 
-// LinkEndpointID represents a data link layer endpoint.
-type LinkEndpointID uint64
-
 // TransportProtocolNumber is the number of a transport protocol.
 type TransportProtocolNumber uint32