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
|
// Package ethwire provides low level access to the Ethereum network and allows
// you to broadcast data over the network.
package ethwire
import (
"bytes"
"fmt"
"net"
"time"
"github.com/ethereum/eth-go/ethutil"
)
// Connection interface describing the methods required to implement the wire protocol.
type Conn interface {
Write(typ MsgType, v ...interface{}) error
Read() *Msg
}
// The magic token which should be the first 4 bytes of every message and can be used as separator between messages.
var MagicToken = []byte{34, 64, 8, 145}
type MsgType byte
const (
// Values are given explicitly instead of by iota because these values are
// defined by the wire protocol spec; it is easier for humans to ensure
// correctness when values are explicit.
MsgHandshakeTy = 0x00
MsgDiscTy = 0x01
MsgPingTy = 0x02
MsgPongTy = 0x03
MsgGetPeersTy = 0x04
MsgPeersTy = 0x05
MsgStatusTy = 0x10
MsgGetTxsTy = 0x11
MsgTxTy = 0x12
MsgGetBlockHashesTy = 0x13
MsgBlockHashesTy = 0x14
MsgGetBlocksTy = 0x15
MsgBlockTy = 0x16
)
var msgTypeToString = map[MsgType]string{
MsgHandshakeTy: "Handshake",
MsgDiscTy: "Disconnect",
MsgPingTy: "Ping",
MsgPongTy: "Pong",
MsgGetPeersTy: "Get peers",
MsgStatusTy: "Status",
MsgPeersTy: "Peers",
MsgTxTy: "Transactions",
MsgBlockTy: "Blocks",
MsgGetTxsTy: "Get Txs",
MsgGetBlockHashesTy: "Get block hashes",
MsgBlockHashesTy: "Block hashes",
MsgGetBlocksTy: "Get blocks",
}
func (mt MsgType) String() string {
return msgTypeToString[mt]
}
type Msg struct {
Type MsgType // Specifies how the encoded data should be interpreted
//Data []byte
Data *ethutil.Value
}
func NewMessage(msgType MsgType, data interface{}) *Msg {
return &Msg{
Type: msgType,
Data: ethutil.NewValue(data),
}
}
type Messages []*Msg
// The basic message reader waits for data on the given connection, decoding
// and doing a few sanity checks such as if there's a data type and
// unmarhals the given data
func ReadMessages(conn net.Conn) (msgs []*Msg, err error) {
// The recovering function in case anything goes horribly wrong
defer func() {
if r := recover(); r != nil {
err = fmt.Errorf("ethwire.ReadMessage error: %v", r)
}
}()
var (
buff []byte
messages [][]byte
msgLength int
)
for {
// Give buffering some time
conn.SetReadDeadline(time.Now().Add(100 * time.Millisecond))
// Create a new temporarily buffer
b := make([]byte, 1440)
n, _ := conn.Read(b)
if err != nil && n == 0 {
if err.Error() != "EOF" {
fmt.Println("err now", err)
return nil, err
} else {
break
}
}
if n == 0 && len(buff) == 0 {
continue
}
buff = append(buff, b[:n]...)
if msgLength == 0 {
// Check if the received 4 first bytes are the magic token
if bytes.Compare(MagicToken, buff[:4]) != 0 {
return nil, fmt.Errorf("MagicToken mismatch. Received %v", buff[:4])
}
// Read the length of the message
msgLength = int(ethutil.BytesToNumber(buff[4:8]))
// Remove the token and length
buff = buff[8:]
}
if len(buff) >= msgLength {
messages = append(messages, buff[:msgLength])
buff = buff[msgLength:]
msgLength = 0
if len(buff) == 0 {
break
}
}
}
for _, m := range messages {
decoder := ethutil.NewValueFromBytes(m)
// Type of message
t := decoder.Get(0).Uint()
// Actual data
d := decoder.SliceFrom(1)
msgs = append(msgs, &Msg{Type: MsgType(t), Data: d})
}
return
}
// The basic message writer takes care of writing data over the given
// connection and does some basic error checking
func WriteMessage(conn net.Conn, msg *Msg) error {
var pack []byte
// Encode the type and the (RLP encoded) data for sending over the wire
encoded := ethutil.NewValue(append([]interface{}{byte(msg.Type)}, msg.Data.Slice()...)).Encode()
payloadLength := ethutil.NumberToBytes(uint32(len(encoded)), 32)
// Write magic token and payload length (first 8 bytes)
pack = append(MagicToken, payloadLength...)
pack = append(pack, encoded...)
//fmt.Printf("payload %v (%v) %q\n", msg.Type, conn.RemoteAddr(), encoded)
// Write to the connection
_, err := conn.Write(pack)
if err != nil {
return err
}
return nil
}
|
