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// 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 (
"encoding/binary"
"github.com/google/nftables/binaryutil"
"github.com/mdlayher/netlink"
"golang.org/x/sys/unix"
)
type HashType uint32
const (
HashTypeJenkins HashType = unix.NFT_HASH_JENKINS
HashTypeSym HashType = unix.NFT_HASH_SYM
)
// Hash defines type for nftables internal hashing functions
type Hash struct {
SourceRegister uint32
DestRegister uint32
Length uint32
Modulus uint32
Seed uint32
Offset uint32
Type HashType
}
func (e *Hash) marshal(fam byte) ([]byte, error) {
hashAttrs := []netlink.Attribute{
{Type: unix.NFTA_HASH_SREG, Data: binaryutil.BigEndian.PutUint32(uint32(e.SourceRegister))},
{Type: unix.NFTA_HASH_DREG, Data: binaryutil.BigEndian.PutUint32(uint32(e.DestRegister))},
{Type: unix.NFTA_HASH_LEN, Data: binaryutil.BigEndian.PutUint32(uint32(e.Length))},
{Type: unix.NFTA_HASH_MODULUS, Data: binaryutil.BigEndian.PutUint32(uint32(e.Modulus))},
}
if e.Seed != 0 {
hashAttrs = append(hashAttrs, netlink.Attribute{
Type: unix.NFTA_HASH_SEED, Data: binaryutil.BigEndian.PutUint32(uint32(e.Seed)),
})
}
hashAttrs = append(hashAttrs, []netlink.Attribute{
{Type: unix.NFTA_HASH_OFFSET, Data: binaryutil.BigEndian.PutUint32(uint32(e.Offset))},
{Type: unix.NFTA_HASH_TYPE, Data: binaryutil.BigEndian.PutUint32(uint32(e.Type))},
}...)
data, err := netlink.MarshalAttributes(hashAttrs)
if err != nil {
return nil, err
}
return netlink.MarshalAttributes([]netlink.Attribute{
{Type: unix.NFTA_EXPR_NAME, Data: []byte("hash\x00")},
{Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data},
})
}
func (e *Hash) unmarshal(fam byte, data []byte) error {
ad, err := netlink.NewAttributeDecoder(data)
if err != nil {
return err
}
ad.ByteOrder = binary.BigEndian
for ad.Next() {
switch ad.Type() {
case unix.NFTA_HASH_SREG:
e.SourceRegister = ad.Uint32()
case unix.NFTA_HASH_DREG:
e.DestRegister = ad.Uint32()
case unix.NFTA_HASH_LEN:
e.Length = ad.Uint32()
case unix.NFTA_HASH_MODULUS:
e.Modulus = ad.Uint32()
case unix.NFTA_HASH_SEED:
e.Seed = ad.Uint32()
case unix.NFTA_HASH_OFFSET:
e.Offset = ad.Uint32()
case unix.NFTA_HASH_TYPE:
e.Type = HashType(ad.Uint32())
}
}
return ad.Err()
}
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