aboutsummaryrefslogtreecommitdiffstats
path: root/ethwire/messaging.go
blob: 651bf4710c3e230b74c9d228cb5a36fd30409eaf (plain) (blame)
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
package ethwire

import (
    "bytes"
    "errors"
    "fmt"
    "github.com/ethereum/eth-go/ethutil"
    "net"
    "time"
)

// Message:
// [4 bytes token] RLP([TYPE, DATA])
// Refer to http://wiki.ethereum.org/index.php/Wire_Protocol

// The magic token which should be the first 4 bytes of every message.
var MagicToken = []byte{34, 64, 8, 145}

type MsgType byte

const (
    MsgHandshakeTy  = 0x00
    MsgDiscTy       = 0x01
    MsgPingTy       = 0x02
    MsgPongTy       = 0x03
    MsgGetPeersTy   = 0x10
    MsgPeersTy      = 0x11
    MsgTxTy         = 0x12
    MsgBlockTy      = 0x13
    MsgGetChainTy   = 0x14
    MsgNotInChainTy = 0x15

    MsgTalkTy = 0xff
)

var msgTypeToString = map[MsgType]string{
    MsgHandshakeTy:  "Handshake",
    MsgDiscTy:       "Disconnect",
    MsgPingTy:       "Ping",
    MsgPongTy:       "Pong",
    MsgGetPeersTy:   "Get peers",
    MsgPeersTy:      "Peers",
    MsgTxTy:         "Transactions",
    MsgBlockTy:      "Blocks",
    MsgGetChainTy:   "Get chain",
    MsgNotInChainTy: "Not in chain",
}

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),
    }
}

func ReadMessage(data []byte) (msg *Msg, remaining []byte, done bool, err error) {
    if len(data) == 0 {
        return nil, nil, true, nil
    }

    if len(data) <= 8 {
        return nil, remaining, false, errors.New("Invalid message")
    }

    // Check if the received 4 first bytes are the magic token
    if bytes.Compare(MagicToken, data[:4]) != 0 {
        return nil, nil, false, fmt.Errorf("MagicToken mismatch. Received %v", data[:4])
    }

    messageLength := ethutil.BytesToNumber(data[4:8])
    remaining = data[8+messageLength:]
    if int(messageLength) > len(data[8:]) {
        return nil, nil, false, fmt.Errorf("message length %d, expected %d", len(data[8:]), messageLength)
    }

    message := data[8 : 8+messageLength]
    decoder := ethutil.NewValueFromBytes(message)
    // Type of message
    t := decoder.Get(0).Uint()
    // Actual data
    d := decoder.SliceFrom(1)

    msg = &Msg{
        Type: MsgType(t),
        Data: d,
    }

    return
}

func bufferedRead(conn net.Conn) ([]byte, error) {
    return nil, nil
}

// 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)
        }
    }()

    // Buff for writing network message to
    //buff := make([]byte, 1440)
    var buff []byte
    var totalBytes int
    for {
        // Give buffering some time
        conn.SetReadDeadline(time.Now().Add(20 * time.Millisecond))
        // Create a new temporarily buffer
        b := make([]byte, 1440)
        // Wait for a message from this peer
        n, _ := conn.Read(b)
        if err != nil && n == 0 {
            if err.Error() != "EOF" {
                fmt.Println("err now", err)
                return nil, err
            } else {
                fmt.Println("IOF NOW")
                break
            }

            // Messages can't be empty
        } else if n == 0 {
            break
        }

        buff = append(buff, b[:n]...)
        totalBytes += n
    }

    // Reslice buffer
    buff = buff[:totalBytes]
    msg, remaining, done, err := ReadMessage(buff)
    for ; done != true; msg, remaining, done, err = ReadMessage(remaining) {
        //log.Println("rx", msg)

        if msg != nil {
            msgs = append(msgs, msg)
        }
    }

    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
}