aboutsummaryrefslogtreecommitdiffstats
path: root/src/device.go
blob: d32d6486cca952022cb544a327e403279c528978 (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
181
182
183
184
185
186
187
188
189
190
191
package main

import (
	"net"
	"runtime"
	"sync"
	"sync/atomic"
	"time"
)

type Device struct {
	mtu       int32
	log       *Logger // collection of loggers for levels
	idCounter uint    // for assigning debug ids to peers
	fwMark    uint32
	pool      struct {
		// pools objects for reuse
		messageBuffers sync.Pool
	}
	net struct {
		// seperate for performance reasons
		mutex sync.RWMutex
		addr  *net.UDPAddr // UDP source address
		conn  *net.UDPConn // UDP "connection"
	}
	mutex        sync.RWMutex
	privateKey   NoisePrivateKey
	publicKey    NoisePublicKey
	routingTable RoutingTable
	indices      IndexTable
	queue        struct {
		encryption chan *QueueOutboundElement
		decryption chan *QueueInboundElement
		inbound    chan *QueueInboundElement
		handshake  chan QueueHandshakeElement
	}
	signal struct {
		stop chan struct{}
	}
	underLoad   int32 // used as an atomic bool
	ratelimiter Ratelimiter
	peers       map[NoisePublicKey]*Peer
	mac         MACStateDevice
}

func (device *Device) SetPrivateKey(sk NoisePrivateKey) {
	device.mutex.Lock()
	defer device.mutex.Unlock()

	// update key material

	device.privateKey = sk
	device.publicKey = sk.publicKey()
	device.mac.Init(device.publicKey)

	// do DH precomputations

	for _, peer := range device.peers {
		h := &peer.handshake
		h.mutex.Lock()
		h.precomputedStaticStatic = device.privateKey.sharedSecret(h.remoteStatic)
		h.mutex.Unlock()
	}
}

func (device *Device) GetMessageBuffer() *[MaxMessageSize]byte {
	return device.pool.messageBuffers.Get().(*[MaxMessageSize]byte)
}

func (device *Device) PutMessageBuffer(msg *[MaxMessageSize]byte) {
	device.pool.messageBuffers.Put(msg)
}

func NewDevice(tun TUNDevice, logLevel int) *Device {
	device := new(Device)

	device.mutex.Lock()
	defer device.mutex.Unlock()

	device.log = NewLogger(logLevel)
	device.peers = make(map[NoisePublicKey]*Peer)
	device.indices.Init()
	device.ratelimiter.Init()
	device.routingTable.Reset()

	// listen

	device.net.mutex.Lock()
	device.net.conn, _ = net.ListenUDP("udp", device.net.addr)
	addr := device.net.conn.LocalAddr()
	device.net.addr, _ = net.ResolveUDPAddr(addr.Network(), addr.String())
	device.net.mutex.Unlock()

	// setup pools

	device.pool.messageBuffers = sync.Pool{
		New: func() interface{} {
			return new([MaxMessageSize]byte)
		},
	}

	// create queues

	device.queue.handshake = make(chan QueueHandshakeElement, QueueHandshakeSize)
	device.queue.encryption = make(chan *QueueOutboundElement, QueueOutboundSize)
	device.queue.decryption = make(chan *QueueInboundElement, QueueInboundSize)
	device.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)

	// prepare signals

	device.signal.stop = make(chan struct{})

	// start workers

	for i := 0; i < runtime.NumCPU(); i += 1 {
		go device.RoutineEncryption()
		go device.RoutineDecryption()
		go device.RoutineHandshake()
	}

	go device.RoutineBusyMonitor()
	go device.RoutineMTUUpdater(tun)
	go device.RoutineWriteToTUN(tun)
	go device.RoutineReadFromTUN(tun)
	go device.RoutineReceiveIncomming()
	go device.ratelimiter.RoutineGarbageCollector(device.signal.stop)

	return device
}

func (device *Device) RoutineMTUUpdater(tun TUNDevice) {
	logError := device.log.Error
	for ; ; time.Sleep(5 * time.Second) {

		// load updated MTU

		mtu, err := tun.MTU()
		if err != nil {
			logError.Println("Failed to load updated MTU of device:", err)
			continue
		}

		// upper bound of mtu

		if mtu+MessageTransportSize > MaxMessageSize {
			mtu = MaxMessageSize - MessageTransportSize
		}
		atomic.StoreInt32(&device.mtu, int32(mtu))
	}
}

func (device *Device) LookupPeer(pk NoisePublicKey) *Peer {
	device.mutex.RLock()
	defer device.mutex.RUnlock()
	return device.peers[pk]
}

func (device *Device) RemovePeer(key NoisePublicKey) {
	device.mutex.Lock()
	defer device.mutex.Unlock()

	peer, ok := device.peers[key]
	if !ok {
		return
	}
	peer.mutex.Lock()
	device.routingTable.RemovePeer(peer)
	delete(device.peers, key)
	peer.Close()
}

func (device *Device) RemoveAllPeers() {
	device.mutex.Lock()
	defer device.mutex.Unlock()

	for key, peer := range device.peers {
		peer.mutex.Lock()
		delete(device.peers, key)
		peer.Close()
		peer.mutex.Unlock()
	}
}

func (device *Device) Close() {
	device.RemoveAllPeers()
	close(device.signal.stop)
}

func (device *Device) Wait() {
	<-device.signal.stop
}