99 lines
2.9 KiB
Go
99 lines
2.9 KiB
Go
// Copyright 2018 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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type HashType uint32
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const (
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HashTypeJenkins HashType = unix.NFT_HASH_JENKINS
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HashTypeSym HashType = unix.NFT_HASH_SYM
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)
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// Hash defines type for nftables internal hashing functions
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type Hash struct {
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SourceRegister uint32
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DestRegister uint32
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Length uint32
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Modulus uint32
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Seed uint32
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Offset uint32
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Type HashType
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}
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func (e *Hash) marshal(fam byte) ([]byte, error) {
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data, err := e.marshalData(fam)
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if err != nil {
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return nil, err
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}
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return netlink.MarshalAttributes([]netlink.Attribute{
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{Type: unix.NFTA_EXPR_NAME, Data: []byte("hash\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 *Hash) marshalData(fam byte) ([]byte, error) {
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hashAttrs := []netlink.Attribute{
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{Type: unix.NFTA_HASH_SREG, Data: binaryutil.BigEndian.PutUint32(uint32(e.SourceRegister))},
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{Type: unix.NFTA_HASH_DREG, Data: binaryutil.BigEndian.PutUint32(uint32(e.DestRegister))},
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{Type: unix.NFTA_HASH_LEN, Data: binaryutil.BigEndian.PutUint32(uint32(e.Length))},
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{Type: unix.NFTA_HASH_MODULUS, Data: binaryutil.BigEndian.PutUint32(uint32(e.Modulus))},
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}
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if e.Seed != 0 {
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hashAttrs = append(hashAttrs, netlink.Attribute{
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Type: unix.NFTA_HASH_SEED, Data: binaryutil.BigEndian.PutUint32(uint32(e.Seed)),
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})
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}
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hashAttrs = append(hashAttrs, []netlink.Attribute{
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{Type: unix.NFTA_HASH_OFFSET, Data: binaryutil.BigEndian.PutUint32(uint32(e.Offset))},
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{Type: unix.NFTA_HASH_TYPE, Data: binaryutil.BigEndian.PutUint32(uint32(e.Type))},
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}...)
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return netlink.MarshalAttributes(hashAttrs)
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}
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func (e *Hash) unmarshal(fam byte, 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_HASH_SREG:
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e.SourceRegister = ad.Uint32()
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case unix.NFTA_HASH_DREG:
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e.DestRegister = ad.Uint32()
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case unix.NFTA_HASH_LEN:
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e.Length = ad.Uint32()
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case unix.NFTA_HASH_MODULUS:
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e.Modulus = ad.Uint32()
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case unix.NFTA_HASH_SEED:
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e.Seed = ad.Uint32()
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case unix.NFTA_HASH_OFFSET:
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e.Offset = ad.Uint32()
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case unix.NFTA_HASH_TYPE:
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e.Type = HashType(ad.Uint32())
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}
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}
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return ad.Err()
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}
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