135 lines
3.9 KiB
Go
135 lines
3.9 KiB
Go
// 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 PayloadBase uint32
|
|
type PayloadCsumType uint32
|
|
type PayloadOperationType uint32
|
|
|
|
// Possible PayloadBase values.
|
|
const (
|
|
PayloadBaseLLHeader PayloadBase = unix.NFT_PAYLOAD_LL_HEADER
|
|
PayloadBaseNetworkHeader PayloadBase = unix.NFT_PAYLOAD_NETWORK_HEADER
|
|
PayloadBaseTransportHeader PayloadBase = unix.NFT_PAYLOAD_TRANSPORT_HEADER
|
|
)
|
|
|
|
// Possible PayloadCsumType values.
|
|
const (
|
|
CsumTypeNone PayloadCsumType = unix.NFT_PAYLOAD_CSUM_NONE
|
|
CsumTypeInet PayloadCsumType = unix.NFT_PAYLOAD_CSUM_INET
|
|
)
|
|
|
|
// Possible PayloadOperationType values.
|
|
const (
|
|
PayloadLoad PayloadOperationType = iota
|
|
PayloadWrite
|
|
)
|
|
|
|
type Payload struct {
|
|
OperationType PayloadOperationType
|
|
DestRegister uint32
|
|
SourceRegister uint32
|
|
Base PayloadBase
|
|
Offset uint32
|
|
Len uint32
|
|
CsumType PayloadCsumType
|
|
CsumOffset uint32
|
|
CsumFlags uint32
|
|
}
|
|
|
|
func (e *Payload) marshal(fam byte) ([]byte, error) {
|
|
data, err := e.marshalData(fam)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return netlink.MarshalAttributes([]netlink.Attribute{
|
|
{Type: unix.NFTA_EXPR_NAME, Data: []byte("payload\x00")},
|
|
{Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data},
|
|
})
|
|
}
|
|
|
|
func (e *Payload) marshalData(fam byte) ([]byte, error) {
|
|
var attrs []netlink.Attribute
|
|
|
|
if e.OperationType == PayloadWrite {
|
|
attrs = []netlink.Attribute{
|
|
{Type: unix.NFTA_PAYLOAD_SREG, Data: binaryutil.BigEndian.PutUint32(e.SourceRegister)},
|
|
}
|
|
} else {
|
|
attrs = []netlink.Attribute{
|
|
{Type: unix.NFTA_PAYLOAD_DREG, Data: binaryutil.BigEndian.PutUint32(e.DestRegister)},
|
|
}
|
|
}
|
|
|
|
attrs = append(attrs,
|
|
netlink.Attribute{Type: unix.NFTA_PAYLOAD_BASE, Data: binaryutil.BigEndian.PutUint32(uint32(e.Base))},
|
|
netlink.Attribute{Type: unix.NFTA_PAYLOAD_OFFSET, Data: binaryutil.BigEndian.PutUint32(e.Offset)},
|
|
netlink.Attribute{Type: unix.NFTA_PAYLOAD_LEN, Data: binaryutil.BigEndian.PutUint32(e.Len)},
|
|
)
|
|
|
|
if e.CsumType > 0 {
|
|
attrs = append(attrs,
|
|
netlink.Attribute{Type: unix.NFTA_PAYLOAD_CSUM_TYPE, Data: binaryutil.BigEndian.PutUint32(uint32(e.CsumType))},
|
|
netlink.Attribute{Type: unix.NFTA_PAYLOAD_CSUM_OFFSET, Data: binaryutil.BigEndian.PutUint32(uint32(e.CsumOffset))},
|
|
)
|
|
if e.CsumFlags > 0 {
|
|
attrs = append(attrs,
|
|
netlink.Attribute{Type: unix.NFTA_PAYLOAD_CSUM_FLAGS, Data: binaryutil.BigEndian.PutUint32(e.CsumFlags)},
|
|
)
|
|
}
|
|
}
|
|
|
|
return netlink.MarshalAttributes(attrs)
|
|
}
|
|
|
|
func (e *Payload) 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_PAYLOAD_DREG:
|
|
e.DestRegister = ad.Uint32()
|
|
case unix.NFTA_PAYLOAD_SREG:
|
|
e.SourceRegister = ad.Uint32()
|
|
e.OperationType = PayloadWrite
|
|
case unix.NFTA_PAYLOAD_BASE:
|
|
e.Base = PayloadBase(ad.Uint32())
|
|
case unix.NFTA_PAYLOAD_OFFSET:
|
|
e.Offset = ad.Uint32()
|
|
case unix.NFTA_PAYLOAD_LEN:
|
|
e.Len = ad.Uint32()
|
|
case unix.NFTA_PAYLOAD_CSUM_TYPE:
|
|
e.CsumType = PayloadCsumType(ad.Uint32())
|
|
case unix.NFTA_PAYLOAD_CSUM_OFFSET:
|
|
e.CsumOffset = ad.Uint32()
|
|
case unix.NFTA_PAYLOAD_CSUM_FLAGS:
|
|
e.CsumFlags = ad.Uint32()
|
|
}
|
|
}
|
|
return ad.Err()
|
|
}
|