1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
// 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) {
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)},
)
}
}
data, err := netlink.MarshalAttributes(attrs)
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) 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()
}
|
