99 lines
2.6 KiB
Go
99 lines
2.6 KiB
Go
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// Copyright 2019 Google LLC. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package expr
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import (
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"encoding/binary"
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"github.com/google/nftables/binaryutil"
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"github.com/mdlayher/netlink"
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"golang.org/x/sys/unix"
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)
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// Range implements range expression
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type Range struct {
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Op CmpOp
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Register uint32
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FromData []byte
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ToData []byte
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}
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func (e *Range) marshal() ([]byte, error) {
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var attrs []netlink.Attribute
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var err error
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var rangeFromData, rangeToData []byte
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if e.Register > 0 {
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attrs = append(attrs, netlink.Attribute{Type: unix.NFTA_RANGE_SREG, Data: binaryutil.BigEndian.PutUint32(e.Register)})
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}
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attrs = append(attrs, netlink.Attribute{Type: unix.NFTA_RANGE_OP, Data: binaryutil.BigEndian.PutUint32(uint32(e.Op))})
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if len(e.FromData) > 0 {
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rangeFromData, err = nestedAttr(e.FromData, unix.NFTA_RANGE_FROM_DATA)
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if err != nil {
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return nil, err
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}
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}
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if len(e.ToData) > 0 {
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rangeToData, err = nestedAttr(e.ToData, unix.NFTA_RANGE_TO_DATA)
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if err != nil {
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return nil, err
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}
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}
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data, err := netlink.MarshalAttributes(attrs)
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if err != nil {
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return nil, err
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}
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data = append(data, rangeFromData...)
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data = append(data, rangeToData...)
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return netlink.MarshalAttributes([]netlink.Attribute{
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{Type: unix.NFTA_EXPR_NAME, Data: []byte("range\x00")},
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{Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data},
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})
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}
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func (e *Range) unmarshal(data []byte) error {
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ad, err := netlink.NewAttributeDecoder(data)
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if err != nil {
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return err
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}
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ad.ByteOrder = binary.BigEndian
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for ad.Next() {
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switch ad.Type() {
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case unix.NFTA_RANGE_OP:
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e.Op = CmpOp(ad.Uint32())
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case unix.NFTA_RANGE_SREG:
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e.Register = ad.Uint32()
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case unix.NFTA_RANGE_FROM_DATA:
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e.FromData = ad.Bytes()
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case unix.NFTA_RANGE_TO_DATA:
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e.ToData = ad.Bytes()
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}
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}
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return ad.Err()
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}
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func nestedAttr(data []byte, attrType uint16) ([]byte, error) {
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ae := netlink.NewAttributeEncoder()
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ae.Do(unix.NLA_F_NESTED|attrType, func() ([]byte, error) {
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nae := netlink.NewAttributeEncoder()
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nae.ByteOrder = binary.BigEndian
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nae.Bytes(unix.NFTA_DATA_VALUE, data)
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return nae.Encode()
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})
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return ae.Encode()
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}
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