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
|
package main
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
"net"
"time"
"github.com/charmbracelet/log"
pb "github.com/meshnet-gophers/meshtastic-go/meshtastic"
"github.com/meshnet-gophers/meshtastic-go/radio"
)
var (
errInvalidOpcode = errors.New("invalid opcode")
errInvalidLength = errors.New("invalid length")
)
// Implements MeshIf
type KavaIf struct {
Address string
KeepAlivePeriod time.Duration
Channels *pb.ChannelSet
logger *log.Logger
conn net.Conn
modemTimeOffset uint64
}
func NewKavaConn(address string, keepAlive time.Duration, channels *pb.ChannelSet) *KavaIf {
logger := log.WithPrefix("Kava")
return &KavaIf{
Address: address,
KeepAlivePeriod: keepAlive,
Channels: channels,
logger: logger,
}
}
func (k *KavaIf) Open() error {
conn, err := net.Dial("tcp", k.Address)
if err != nil {
return fmt.Errorf("connecting to modem: %w", err)
}
if k.KeepAlivePeriod > 0 {
tcpconn := conn.(*net.TCPConn)
tcpconn.SetKeepAlive(true)
tcpconn.SetKeepAlivePeriod(k.KeepAlivePeriod)
}
k.conn = conn
return nil
}
func (k *KavaIf) Close() error {
return k.conn.Close()
}
func (k *KavaIf) ReadMeshPacket() (*pb.MeshPacket, uint64, error) {
var header [4]byte
var err error
for {
if _, err = io.ReadFull(k.conn, header[0:4]); err != nil {
return nil, 0, err
}
opcode := binary.LittleEndian.Uint16(header[0:2])
length := binary.LittleEndian.Uint16(header[2:4])
if length <= 0 {
continue
} else if length > 255+12 {
return nil, 0, errInvalidLength
}
switch opcode {
case 0x1007:
var ts [8]byte
if _, err = io.ReadFull(k.conn, ts[:]); err != nil {
return nil, 0, err
}
uptime := binary.LittleEndian.Uint64(ts[:])
k.modemTimeOffset = uint64(time.Now().UnixMicro()) - uptime
k.logger.Info("}} Modem uptime", "µs", uptime, "Δ-to-now", fmt.Sprintf("%+d", k.modemTimeOffset))
continue
case 0x0001:
var message [272]byte
if _, err := io.ReadFull(k.conn, message[:length]); err != nil {
return nil, 0, err
}
if length < (12 /*kava*/ + 16 /*m8c*/) {
return nil, 0, errInvalidLength
}
modemTs := binary.LittleEndian.Uint64(message[0:8])
rssi := int16(binary.LittleEndian.Uint16(message[8:10]))
snr := int16(binary.LittleEndian.Uint16(message[10:12]))
ts := int64(modemTs + k.modemTimeOffset)
timestamp := time.UnixMicro(ts)
data := message[12:length]
flags := RadioHeaderFlag(data[12])
channelHash := data[13]
payload := data[16:]
p := pb.MeshPacket{
To: binary.LittleEndian.Uint32(data[0:4]),
From: binary.LittleEndian.Uint32(data[4:8]),
Id: binary.LittleEndian.Uint32(data[8:12]),
RxTime: uint32(timestamp.Unix()),
RxSnr: float32(snr),
RxRssi: int32(rssi),
HopLimit: uint32(flags.HopLimit()),
HopStart: uint32(flags.HopStart()),
WantAck: flags.WantACK() == 1,
ViaMqtt: flags.MQTT() == 1,
NextHop: uint32(data[14]),
RelayNode: uint32(data[15]),
Channel: uint32(channelHash),
PkiEncrypted: channelHash == 0x00,
PayloadVariant: &pb.MeshPacket_Encrypted{Encrypted: payload},
}
return &p, uint64(ts), nil
default:
return nil, 0, errInvalidOpcode
}
}
}
func (k *KavaIf) WriteMeshPacket(p *pb.MeshPacket) error {
viaMQTT := uint32(bool2Int(p.ViaMqtt))
wantAck := uint32(bool2Int(p.WantAck))
flags := (p.HopStart << 5) | (viaMQTT << 4) | (wantAck << 3) | p.HopLimit
var chash uint32
if p.PkiEncrypted {
chash = 0x00
} else {
channel := k.Channels.Settings[p.Channel]
chash, _ = radio.ChannelHash(channel.Name, channel.Psk)
}
buf := bytes.NewBuffer(nil)
binary.Write(buf, binary.LittleEndian, uint32(p.To))
binary.Write(buf, binary.LittleEndian, uint32(p.From))
binary.Write(buf, binary.LittleEndian, uint32(p.Id))
binary.Write(buf, binary.LittleEndian, uint8(flags))
binary.Write(buf, binary.LittleEndian, uint8(chash))
binary.Write(buf, binary.LittleEndian, uint8(p.NextHop))
binary.Write(buf, binary.LittleEndian, uint8(p.RelayNode))
buf.Write(p.GetEncrypted())
b := buf.Bytes()
modemCmd := append([]byte{1, 0, byte(len(b)), 0}, b...)
if _, err := k.conn.Write(modemCmd); err != nil {
return err
}
return nil
}
func bool2Int(b bool) int {
var i int
if b {
i = 1
} else {
i = 0
}
return i
}
|
