Remove ARP address workaround

- Make AddressableEndpoint optional for NetworkEndpoint.
Not all NetworkEndpoints need to support addressing (e.g. ARP), so
AddressableEndpoint should only be implemented for protocols that
support addressing such as IPv4 and IPv6.

With this change, tcpip.ErrNotSupported will be returned by the stack
when attempting to modify addresses on a network endpoint that does
not support addressing.

Now that packets are fully handled at the network layer, and (with this
change) addresses are optional for network endpoints, we no longer need
the workaround for ARP where a fake ARP address was added to each NIC
that performs ARP so that packets would be delivered to the ARP layer.

PiperOrigin-RevId: 342722547

1 files changed, 24 insertions, 8 deletions

diff --git a/pkg/tcpip/network/ip_test.go b/pkg/tcpip/network/ip_test.go
index 12c16fde4..d49c44846 100644
--- a/pkg/tcpip/network/ip_test.go
+++ b/pkg/tcpip/network/ip_test.go
@@ -670,8 +670,12 @@ func TestReceive(t *testing.T) {
 				t.Fatalf("ep.Enable(): %s", err)
 			}
 
-			if ep, err := ep.AddAndAcquirePermanentAddress(test.epAddr, stack.CanBePrimaryEndpoint, stack.AddressConfigStatic, false /* deprecated */); err != nil {
-				t.Fatalf("ep.AddAndAcquirePermanentAddress(%s, CanBePrimaryEndpoint, AddressConfigStatic, false): %s", test.epAddr, err)
+			addressableEndpoint, ok := ep.(stack.AddressableEndpoint)
+			if !ok {
+				t.Fatalf("expected network endpoint with number = %d to implement stack.AddressableEndpoint", test.protoNum)
+			}
+			if ep, err := addressableEndpoint.AddAndAcquirePermanentAddress(test.epAddr, stack.CanBePrimaryEndpoint, stack.AddressConfigStatic, false /* deprecated */); err != nil {
+				t.Fatalf("addressableEndpoint.AddAndAcquirePermanentAddress(%s, CanBePrimaryEndpoint, AddressConfigStatic, false): %s", test.epAddr, err)
 			} else {
 				ep.DecRef()
 			}
@@ -778,9 +782,13 @@ func TestIPv4ReceiveControl(t *testing.T) {
 			nic.testObject.typ = c.expectedTyp
 			nic.testObject.extra = c.expectedExtra
 
+			addressableEndpoint, ok := ep.(stack.AddressableEndpoint)
+			if !ok {
+				t.Fatal("expected IPv4 network endpoint to implement stack.AddressableEndpoint")
+			}
 			addr := localIPv4Addr.WithPrefix()
-			if ep, err := ep.AddAndAcquirePermanentAddress(addr, stack.CanBePrimaryEndpoint, stack.AddressConfigStatic, false /* deprecated */); err != nil {
-				t.Fatalf("ep.AddAndAcquirePermanentAddress(%s, CanBePrimaryEndpoint, AddressConfigStatic, false): %s", addr, err)
+			if ep, err := addressableEndpoint.AddAndAcquirePermanentAddress(addr, stack.CanBePrimaryEndpoint, stack.AddressConfigStatic, false /* deprecated */); err != nil {
+				t.Fatalf("addressableEndpoint.AddAndAcquirePermanentAddress(%s, CanBePrimaryEndpoint, AddressConfigStatic, false): %s", addr, err)
 			} else {
 				ep.DecRef()
 			}
@@ -863,9 +871,13 @@ func TestIPv4FragmentationReceive(t *testing.T) {
 		t.Fatalf("failed to parse packet: %x", pkt.Data.ToView())
 	}
 
+	addressableEndpoint, ok := ep.(stack.AddressableEndpoint)
+	if !ok {
+		t.Fatal("expected IPv4 network endpoint to implement stack.AddressableEndpoint")
+	}
 	addr := localIPv4Addr.WithPrefix()
-	if ep, err := ep.AddAndAcquirePermanentAddress(addr, stack.CanBePrimaryEndpoint, stack.AddressConfigStatic, false /* deprecated */); err != nil {
-		t.Fatalf("ep.AddAndAcquirePermanentAddress(%s, CanBePrimaryEndpoint, AddressConfigStatic, false): %s", addr, err)
+	if ep, err := addressableEndpoint.AddAndAcquirePermanentAddress(addr, stack.CanBePrimaryEndpoint, stack.AddressConfigStatic, false /* deprecated */); err != nil {
+		t.Fatalf("addressableEndpoint.AddAndAcquirePermanentAddress(%s, CanBePrimaryEndpoint, AddressConfigStatic, false): %s", addr, err)
 	} else {
 		ep.DecRef()
 	}
@@ -1038,9 +1050,13 @@ func TestIPv6ReceiveControl(t *testing.T) {
 			// Set ICMPv6 checksum.
 			icmp.SetChecksum(header.ICMPv6Checksum(icmp, outerSrcAddr, localIPv6Addr, buffer.VectorisedView{}))
 
+			addressableEndpoint, ok := ep.(stack.AddressableEndpoint)
+			if !ok {
+				t.Fatal("expected IPv6 network endpoint to implement stack.AddressableEndpoint")
+			}
 			addr := localIPv6Addr.WithPrefix()
-			if ep, err := ep.AddAndAcquirePermanentAddress(addr, stack.CanBePrimaryEndpoint, stack.AddressConfigStatic, false /* deprecated */); err != nil {
-				t.Fatalf("ep.AddAndAcquirePermanentAddress(%s, CanBePrimaryEndpoint, AddressConfigStatic, false): %s", addr, err)
+			if ep, err := addressableEndpoint.AddAndAcquirePermanentAddress(addr, stack.CanBePrimaryEndpoint, stack.AddressConfigStatic, false /* deprecated */); err != nil {
+				t.Fatalf("addressableEndpoint.AddAndAcquirePermanentAddress(%s, CanBePrimaryEndpoint, AddressConfigStatic, false): %s", addr, err)
 			} else {
 				ep.DecRef()
 			}