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
|
// Copyright 2021 The gVisor Authors.
//
// 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 header
import "encoding/binary"
// These constants are declared in linux/virtio_net.h.
const (
_VIRTIO_NET_HDR_F_NEEDS_CSUM = 1
_VIRTIO_NET_HDR_GSO_NONE = 0
_VIRTIO_NET_HDR_GSO_TCPV4 = 1
_VIRTIO_NET_HDR_GSO_TCPV6 = 4
)
const (
// VirtioNetHeaderSize is the size of VirtioNetHeader in bytes.
VirtioNetHeaderSize = 10
)
// Offsets for fields in the virtio net header.
const (
flags = 0
gsoType = 1
hdrLen = 2
gsoSize = 4
csumStart = 6
csumOffset = 8
)
// VirtioNetHeaderFields is the Go equivalent of the struct declared in
// linux/virtio_net.h.
type VirtioNetHeaderFields struct {
Flags uint8
GSOType uint8
HdrLen uint16
GSOSize uint16
CSumStart uint16
CSumOffset uint16
}
// VirtioNetHeader represents a virtio net header stored in a byte array.
type VirtioNetHeader []byte
// Flags returns the "flags" field of the virtio net header.
func (v VirtioNetHeader) Flags() uint8 {
return uint8(v[flags])
}
// GSOType returns the "gsoType" field of the virtio net header.
func (v VirtioNetHeader) GSOType() uint8 {
return uint8(v[gsoType])
}
// HdrLen returns the "hdrLen" field of the virtio net header.
func (v VirtioNetHeader) HdrLen() uint16 {
return binary.BigEndian.Uint16(v[hdrLen:])
}
// GSOSize returns the "gsoSize" field of the virtio net header.
func (v VirtioNetHeader) GSOSize() uint16 {
return binary.BigEndian.Uint16(v[gsoSize:])
}
// CSumStart returns the "csumStart" field of the virtio net header.
func (v VirtioNetHeader) CSumStart() uint16 {
return binary.BigEndian.Uint16(v[csumStart:])
}
// CSumOffset returns the "csumOffset" field of the virtio net header.
func (v VirtioNetHeader) CSumOffset() uint16 {
return binary.BigEndian.Uint16(v[csumOffset:])
}
// Encode encodes all the fields of the virtio net header.
func (v VirtioNetHeader) Encode(f *VirtioNetHeaderFields) {
v[flags] = uint8(f.Flags)
v[gsoType] = uint8(f.GSOType)
binary.BigEndian.PutUint16(v[hdrLen:], f.HdrLen)
binary.BigEndian.PutUint16(v[gsoSize:], f.GSOSize)
binary.BigEndian.PutUint16(v[csumStart:], f.CSumStart)
binary.BigEndian.PutUint16(v[csumOffset:], f.CSumOffset)
}
|
