Change tcpip.Error to an interface

This makes it possible to add data to types that implement tcpip.Error.
ErrBadLinkEndpoint is removed as it is unused.

PiperOrigin-RevId: 354437314

2 files changed, 6 insertions, 6 deletions

diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go
index 5580d6a78..f2403978c 100644
--- a/pkg/tcpip/header/ipv6.go
+++ b/pkg/tcpip/header/ipv6.go
@@ -453,9 +453,9 @@ const (
 )
 
 // ScopeForIPv6Address returns the scope for an IPv6 address.
-func ScopeForIPv6Address(addr tcpip.Address) (IPv6AddressScope, *tcpip.Error) {
+func ScopeForIPv6Address(addr tcpip.Address) (IPv6AddressScope, tcpip.Error) {
 	if len(addr) != IPv6AddressSize {
-		return GlobalScope, tcpip.ErrBadAddress
+		return GlobalScope, &tcpip.ErrBadAddress{}
 	}
 
 	switch {
diff --git a/pkg/tcpip/header/ipv6_test.go b/pkg/tcpip/header/ipv6_test.go
index e3fbd64f3..f10f446a6 100644
--- a/pkg/tcpip/header/ipv6_test.go
+++ b/pkg/tcpip/header/ipv6_test.go
@@ -299,7 +299,7 @@ func TestScopeForIPv6Address(t *testing.T) {
 		name  string
 		addr  tcpip.Address
 		scope header.IPv6AddressScope
-		err   *tcpip.Error
+		err   tcpip.Error
 	}{
 		{
 			name:  "Unique Local",
@@ -329,15 +329,15 @@ func TestScopeForIPv6Address(t *testing.T) {
 			name:  "IPv4",
 			addr:  "\x01\x02\x03\x04",
 			scope: header.GlobalScope,
-			err:   tcpip.ErrBadAddress,
+			err:   &tcpip.ErrBadAddress{},
 		},
 	}
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			got, err := header.ScopeForIPv6Address(test.addr)
-			if err != test.err {
-				t.Errorf("got header.IsV6UniqueLocalAddress(%s) = (_, %v), want = (_, %v)", test.addr, err, test.err)
+			if diff := cmp.Diff(test.err, err); diff != "" {
+				t.Errorf("unexpected error from header.IsV6UniqueLocalAddress(%s), (-want, +got):\n%s", test.addr, diff)
 			}
 			if got != test.scope {
 				t.Errorf("got header.IsV6UniqueLocalAddress(%s) = (%d, _), want = (%d, _)", test.addr, got, test.scope)