Refactor testutil.TestEndpoint and use it instead of limitedEP

The new testutil.MockLinkEndpoint implementation is not composed by
channel.Channel anymore because none of its features were used.

PiperOrigin-RevId: 333167753

2 files changed, 19 insertions, 79 deletions

diff --git a/pkg/tcpip/network/ipv6/BUILD b/pkg/tcpip/network/ipv6/BUILD
index cd5fe3ea8..8bd8f5c52 100644
--- a/pkg/tcpip/network/ipv6/BUILD
+++ b/pkg/tcpip/network/ipv6/BUILD
@@ -35,6 +35,7 @@ go_test(
         "//pkg/tcpip/header",
         "//pkg/tcpip/link/channel",
         "//pkg/tcpip/link/sniffer",
+        "//pkg/tcpip/network/testutil",
         "//pkg/tcpip/stack",
         "//pkg/tcpip/transport/icmp",
         "//pkg/tcpip/transport/udp",
diff --git a/pkg/tcpip/network/ipv6/ipv6_test.go b/pkg/tcpip/network/ipv6/ipv6_test.go
index 9eea1de8d..7d138dadb 100644
--- a/pkg/tcpip/network/ipv6/ipv6_test.go
+++ b/pkg/tcpip/network/ipv6/ipv6_test.go
@@ -23,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/link/channel"
+	"gvisor.dev/gvisor/pkg/tcpip/network/testutil"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/icmp"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
@@ -1715,7 +1716,7 @@ func TestWriteStats(t *testing.T) {
 	tests := []struct {
 		name          string
 		setup         func(*testing.T, *stack.Stack)
-		linkEP        func() stack.LinkEndpoint
+		allowPackets  int
 		expectSent    int
 		expectDropped int
 		expectWritten int
@@ -1724,7 +1725,7 @@ func TestWriteStats(t *testing.T) {
 			name: "Accept all",
 			// No setup needed, tables accept everything by default.
 			setup:         func(*testing.T, *stack.Stack) {},
-			linkEP:        func() stack.LinkEndpoint { return &limitedEP{nPackets} },
+			allowPackets:  math.MaxInt32,
 			expectSent:    nPackets,
 			expectDropped: 0,
 			expectWritten: nPackets,
@@ -1732,7 +1733,7 @@ func TestWriteStats(t *testing.T) {
 			name: "Accept all with error",
 			// No setup needed, tables accept everything by default.
 			setup:         func(*testing.T, *stack.Stack) {},
-			linkEP:        func() stack.LinkEndpoint { return &limitedEP{nPackets - 1} },
+			allowPackets:  nPackets - 1,
 			expectSent:    nPackets - 1,
 			expectDropped: 0,
 			expectWritten: nPackets - 1,
@@ -1752,7 +1753,7 @@ func TestWriteStats(t *testing.T) {
 					t.Fatalf("failed to replace table: %v", err)
 				}
 			},
-			linkEP:        func() stack.LinkEndpoint { return &limitedEP{nPackets} },
+			allowPackets:  math.MaxInt32,
 			expectSent:    0,
 			expectDropped: nPackets,
 			expectWritten: nPackets,
@@ -1777,7 +1778,7 @@ func TestWriteStats(t *testing.T) {
 					t.Fatalf("failed to replace table: %v", err)
 				}
 			},
-			linkEP:        func() stack.LinkEndpoint { return &limitedEP{nPackets} },
+			allowPackets:  math.MaxInt32,
 			expectSent:    nPackets - 1,
 			expectDropped: 1,
 			expectWritten: nPackets,
@@ -1812,7 +1813,8 @@ func TestWriteStats(t *testing.T) {
 		t.Run(writer.name, func(t *testing.T) {
 			for _, test := range tests {
 				t.Run(test.name, func(t *testing.T) {
-					rt := buildRoute(t, nil, test.linkEP())
+					ep := testutil.NewMockLinkEndpoint(header.IPv6MinimumMTU, tcpip.ErrInvalidEndpointState, test.allowPackets)
+					rt := buildRoute(t, ep)
 
 					var pkts stack.PacketBufferList
 					for i := 0; i < nPackets; i++ {
@@ -1843,100 +1845,37 @@ func TestWriteStats(t *testing.T) {
 	}
 }
 
-func buildRoute(t *testing.T, packetCollectorErrors []*tcpip.Error, linkEP stack.LinkEndpoint) stack.Route {
+func buildRoute(t *testing.T, ep stack.LinkEndpoint) stack.Route {
 	s := stack.New(stack.Options{
 		NetworkProtocols: []stack.NetworkProtocol{NewProtocol()},
 	})
-	s.CreateNIC(1, linkEP)
+	if err := s.CreateNIC(1, ep); err != nil {
+		t.Fatalf("CreateNIC(1, _) failed: %s", err)
+	}
 	const (
 		src = "\xfc\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"
 		dst = "\xfc\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02"
 	)
-	s.AddAddress(1, ProtocolNumber, src)
+	if err := s.AddAddress(1, ProtocolNumber, src); err != nil {
+		t.Fatalf("AddAddress(1, %d, _) failed: %s", ProtocolNumber, err)
+	}
 	{
 		subnet, err := tcpip.NewSubnet(dst, tcpip.AddressMask("\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"))
 		if err != nil {
-			t.Fatal(err)
+			t.Fatalf("NewSubnet(_, _) failed: %v", err)
 		}
 		s.SetRouteTable([]tcpip.Route{{
 			Destination: subnet,
 			NIC:         1,
 		}})
 	}
-	rt, err := s.FindRoute(0, src, dst, ProtocolNumber, false /* multicastLoop */)
+	rt, err := s.FindRoute(1, src, dst, ProtocolNumber, false /* multicastLoop */)
 	if err != nil {
-		t.Fatalf("s.FindRoute got %v, want %v", err, nil)
+		t.Fatalf("got FindRoute(1, _, _, %d, false) = %s, want = nil", ProtocolNumber, err)
 	}
 	return rt
 }
 
-// limitedEP is a link endpoint that writes up to a certain number of packets
-// before returning errors.
-type limitedEP struct {
-	limit int
-}
-
-// MTU implements LinkEndpoint.MTU.
-func (*limitedEP) MTU() uint32 {
-	return header.IPv6MinimumMTU
-}
-
-// Capabilities implements LinkEndpoint.Capabilities.
-func (*limitedEP) Capabilities() stack.LinkEndpointCapabilities { return 0 }
-
-// MaxHeaderLength implements LinkEndpoint.MaxHeaderLength.
-func (*limitedEP) MaxHeaderLength() uint16 { return 0 }
-
-// LinkAddress implements LinkEndpoint.LinkAddress.
-func (*limitedEP) LinkAddress() tcpip.LinkAddress { return "" }
-
-// WritePacket implements LinkEndpoint.WritePacket.
-func (ep *limitedEP) WritePacket(*stack.Route, *stack.GSO, tcpip.NetworkProtocolNumber, *stack.PacketBuffer) *tcpip.Error {
-	if ep.limit == 0 {
-		return tcpip.ErrInvalidEndpointState
-	}
-	ep.limit--
-	return nil
-}
-
-// WritePackets implements LinkEndpoint.WritePackets.
-func (ep *limitedEP) WritePackets(_ *stack.Route, _ *stack.GSO, pkts stack.PacketBufferList, _ tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
-	if ep.limit == 0 {
-		return 0, tcpip.ErrInvalidEndpointState
-	}
-	nWritten := ep.limit
-	if nWritten > pkts.Len() {
-		nWritten = pkts.Len()
-	}
-	ep.limit -= nWritten
-	return nWritten, nil
-}
-
-// WriteRawPacket implements LinkEndpoint.WriteRawPacket.
-func (ep *limitedEP) WriteRawPacket(_ buffer.VectorisedView) *tcpip.Error {
-	if ep.limit == 0 {
-		return tcpip.ErrInvalidEndpointState
-	}
-	ep.limit--
-	return nil
-}
-
-// Attach implements LinkEndpoint.Attach.
-func (*limitedEP) Attach(_ stack.NetworkDispatcher) {}
-
-// IsAttached implements LinkEndpoint.IsAttached.
-func (*limitedEP) IsAttached() bool { return false }
-
-// Wait implements LinkEndpoint.Wait.
-func (*limitedEP) Wait() {}
-
-// ARPHardwareType implements LinkEndpoint.ARPHardwareType.
-func (*limitedEP) ARPHardwareType() header.ARPHardwareType { return header.ARPHardwareEther }
-
-// AddHeader implements LinkEndpoint.AddHeader.
-func (*limitedEP) AddHeader(_, _ tcpip.LinkAddress, _ tcpip.NetworkProtocolNumber, _ *stack.PacketBuffer) {
-}
-
 // limitedMatcher is an iptables matcher that matches after a certain number of
 // packets are checked against it.
 type limitedMatcher struct {