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
|
// 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"
)
// Lookup represents a match against the contents of a set.
type Lookup struct {
SourceRegister uint32
DestRegister uint32
IsDestRegSet bool
SetID uint32
SetName string
Invert bool
}
func (e *Lookup) marshal(fam byte) ([]byte, error) {
// See: https://git.netfilter.org/libnftnl/tree/src/expr/lookup.c?id=6dc1c3d8bb64077da7f3f28c7368fb087d10a492#n115
var opAttrs []netlink.Attribute
if e.SourceRegister != 0 {
opAttrs = append(opAttrs, netlink.Attribute{Type: unix.NFTA_LOOKUP_SREG, Data: binaryutil.BigEndian.PutUint32(e.SourceRegister)})
}
if e.IsDestRegSet {
opAttrs = append(opAttrs, netlink.Attribute{Type: unix.NFTA_LOOKUP_DREG, Data: binaryutil.BigEndian.PutUint32(e.DestRegister)})
}
if e.Invert {
opAttrs = append(opAttrs, netlink.Attribute{Type: unix.NFTA_LOOKUP_FLAGS, Data: binaryutil.BigEndian.PutUint32(unix.NFT_LOOKUP_F_INV)})
}
opAttrs = append(opAttrs,
netlink.Attribute{Type: unix.NFTA_LOOKUP_SET, Data: []byte(e.SetName + "\x00")},
netlink.Attribute{Type: unix.NFTA_LOOKUP_SET_ID, Data: binaryutil.BigEndian.PutUint32(e.SetID)},
)
opData, err := netlink.MarshalAttributes(opAttrs)
if err != nil {
return nil, err
}
return netlink.MarshalAttributes([]netlink.Attribute{
{Type: unix.NFTA_EXPR_NAME, Data: []byte("lookup\x00")},
{Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: opData},
})
}
func (e *Lookup) 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_LOOKUP_SET:
e.SetName = ad.String()
case unix.NFTA_LOOKUP_SET_ID:
e.SetID = ad.Uint32()
case unix.NFTA_LOOKUP_SREG:
e.SourceRegister = ad.Uint32()
case unix.NFTA_LOOKUP_DREG:
e.DestRegister = ad.Uint32()
e.IsDestRegSet = true
case unix.NFTA_LOOKUP_FLAGS:
e.Invert = (ad.Uint32() & unix.NFT_LOOKUP_F_INV) != 0
}
}
return ad.Err()
}
|
