/
header.go
184 lines (157 loc) · 4.77 KB
/
header.go
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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
package header
import (
"encoding/binary"
"encoding/json"
"errors"
"fmt"
)
//Version 1 header:
// 0 31
// |-----------------------------------------------------------------------|
// | Version (uint4) | Type (uint4) | Subtype (uint8) | Reserved (uint16) | 32
// |-----------------------------------------------------------------------|
// | Remote index (uint32) | 64
// |-----------------------------------------------------------------------|
// | Message counter | 96
// | (uint64) | 128
// |-----------------------------------------------------------------------|
// | payload... |
type m map[string]interface{}
const (
Version uint8 = 1
Len = 16
)
type MessageType uint8
type MessageSubType uint8
const (
Handshake MessageType = 0
Message MessageType = 1
RecvError MessageType = 2
LightHouse MessageType = 3
Test MessageType = 4
CloseTunnel MessageType = 5
)
var typeMap = map[MessageType]string{
Handshake: "handshake",
Message: "message",
RecvError: "recvError",
LightHouse: "lightHouse",
Test: "test",
CloseTunnel: "closeTunnel",
}
const (
TestRequest MessageSubType = 0
TestReply MessageSubType = 1
)
const (
HandshakeIXPSK0 MessageSubType = 0
HandshakeXXPSK0 MessageSubType = 1
)
var ErrHeaderTooShort = errors.New("header is too short")
var subTypeTestMap = map[MessageSubType]string{
TestRequest: "testRequest",
TestReply: "testReply",
}
var subTypeNoneMap = map[MessageSubType]string{0: "none"}
var subTypeMap = map[MessageType]*map[MessageSubType]string{
Message: &subTypeNoneMap,
RecvError: &subTypeNoneMap,
LightHouse: &subTypeNoneMap,
Test: &subTypeTestMap,
CloseTunnel: &subTypeNoneMap,
Handshake: {
HandshakeIXPSK0: "ix_psk0",
},
}
type H struct {
Version uint8
Type MessageType
Subtype MessageSubType
Reserved uint16
RemoteIndex uint32
MessageCounter uint64
}
// Encode uses the provided byte array to encode the provided header values into.
// Byte array must be capped higher than HeaderLen or this will panic
func Encode(b []byte, v uint8, t MessageType, st MessageSubType, ri uint32, c uint64) []byte {
b = b[:Len]
b[0] = v<<4 | byte(t&0x0f)
b[1] = byte(st)
binary.BigEndian.PutUint16(b[2:4], 0)
binary.BigEndian.PutUint32(b[4:8], ri)
binary.BigEndian.PutUint64(b[8:16], c)
return b
}
// String creates a readable string representation of a header
func (h *H) String() string {
if h == nil {
return "<nil>"
}
return fmt.Sprintf("ver=%d type=%s subtype=%s reserved=%#x remoteindex=%v messagecounter=%v",
h.Version, h.TypeName(), h.SubTypeName(), h.Reserved, h.RemoteIndex, h.MessageCounter)
}
// MarshalJSON creates a json string representation of a header
func (h *H) MarshalJSON() ([]byte, error) {
return json.Marshal(m{
"version": h.Version,
"type": h.TypeName(),
"subType": h.SubTypeName(),
"reserved": h.Reserved,
"remoteIndex": h.RemoteIndex,
"messageCounter": h.MessageCounter,
})
}
// Encode turns header into bytes
func (h *H) Encode(b []byte) ([]byte, error) {
if h == nil {
return nil, errors.New("nil header")
}
return Encode(b, h.Version, h.Type, h.Subtype, h.RemoteIndex, h.MessageCounter), nil
}
// Parse is a helper function to parses given bytes into new Header struct
func (h *H) Parse(b []byte) error {
if len(b) < Len {
return ErrHeaderTooShort
}
// get upper 4 bytes
h.Version = uint8((b[0] >> 4) & 0x0f)
// get lower 4 bytes
h.Type = MessageType(b[0] & 0x0f)
h.Subtype = MessageSubType(b[1])
h.Reserved = binary.BigEndian.Uint16(b[2:4])
h.RemoteIndex = binary.BigEndian.Uint32(b[4:8])
h.MessageCounter = binary.BigEndian.Uint64(b[8:16])
return nil
}
// TypeName will transform the headers message type into a human string
func (h *H) TypeName() string {
return TypeName(h.Type)
}
// TypeName will transform a nebula message type into a human string
func TypeName(t MessageType) string {
if n, ok := typeMap[t]; ok {
return n
}
return "unknown"
}
// SubTypeName will transform the headers message sub type into a human string
func (h *H) SubTypeName() string {
return SubTypeName(h.Type, h.Subtype)
}
// SubTypeName will transform a nebula message sub type into a human string
func SubTypeName(t MessageType, s MessageSubType) string {
if n, ok := subTypeMap[t]; ok {
if x, ok := (*n)[s]; ok {
return x
}
}
return "unknown"
}
// NewHeader turns bytes into a header
func NewHeader(b []byte) (*H, error) {
h := new(H)
if err := h.Parse(b); err != nil {
return nil, err
}
return h, nil
}