add expr.Objref

expr/objref.go

@@ -0,0 +1,58 @@
+// Copyright 2018 Google LLC. All Rights Reserved.
+//
+// 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 expr
+
+import (
+	"github.com/google/nftables/binaryutil"
+	"github.com/mdlayher/netlink"
+	"golang.org/x/sys/unix"
+)
+
+type Objref struct {
+	Type int // TODO: enum
+	Name string
+}
+
+func (e *Objref) marshal() ([]byte, error) {
+	data, err := netlink.MarshalAttributes([]netlink.Attribute{
+		{Type: unix.NFTA_OBJREF_IMM_TYPE, Data: binaryutil.BigEndian.PutUint32(uint32(e.Type))},
+		{Type: unix.NFTA_OBJREF_IMM_NAME, Data: []byte(e.Name)}, // NOT \x00-terminated?!
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return netlink.MarshalAttributes([]netlink.Attribute{
+		{Type: unix.NFTA_EXPR_NAME, Data: []byte("objref\x00")},
+		{Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data},
+	})
+}
+
+func (e *Objref) unmarshal(data []byte) error {
+	attrs, err := netlink.UnmarshalAttributes(data)
+	if err != nil {
+		return err
+	}
+	for _, attr := range attrs {
+		switch attr.Type {
+		case unix.NFTA_OBJREF_IMM_TYPE:
+			e.Type = int(binaryutil.BigEndian.Uint32(attr.Data))
+		case unix.NFTA_OBJREF_IMM_NAME:
+			e.Name = string(attr.Data)
+		}
+	}
+
+	return nil
+}