Migrate clashtcpip to gVisor tcpip copied

internal/gtcpip/errors.go

@@ -0,0 +1,46 @@
+// Copyright 2021 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tcpip
+
+import (
+	"fmt"
+)
+
+// Error represents an error in the netstack error space.
+//
+// The error interface is intentionally omitted to avoid loss of type
+// information that would occur if these errors were passed as error.
+type Error interface {
+	isError()
+
+	// IgnoreStats indicates whether this error should be included in failure
+	// counts in tcpip.Stats structs.
+	IgnoreStats() bool
+
+	fmt.Stringer
+}
+
+// ErrBadAddress indicates a bad address was provided.
+//
+// +stateify savable
+type ErrBadAddress struct{}
+
+func (*ErrBadAddress) isError() {}
+
+// IgnoreStats implements Error.
+func (*ErrBadAddress) IgnoreStats() bool {
+	return false
+}
+func (*ErrBadAddress) String() string { return "bad address" }