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
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
|
/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*
* This is based heavily on timers.c from the kernel implementation.
*/
package main
import (
"math/rand"
"sync"
"sync/atomic"
"time"
)
/* This Timer structure and related functions should roughly copy the interface of
* the Linux kernel's struct timer_list.
*/
type Timer struct {
timer *time.Timer
modifyingLock sync.Mutex
runningLock sync.Mutex
isPending bool
}
func (peer *Peer) NewTimer(expirationFunction func(*Peer)) *Timer {
timer := &Timer{}
timer.timer = time.AfterFunc(time.Hour, func() {
timer.runningLock.Lock()
timer.modifyingLock.Lock()
if !timer.isPending {
timer.modifyingLock.Unlock()
timer.runningLock.Unlock()
return
}
timer.isPending = false
timer.modifyingLock.Unlock()
expirationFunction(peer)
timer.runningLock.Unlock()
})
timer.timer.Stop()
return timer
}
func (timer *Timer) Mod(d time.Duration) {
timer.modifyingLock.Lock()
timer.isPending = true
timer.timer.Reset(d)
timer.modifyingLock.Unlock()
}
func (timer *Timer) Del() {
timer.modifyingLock.Lock()
timer.isPending = false
timer.timer.Stop()
timer.modifyingLock.Unlock()
}
func (timer *Timer) DelSync() {
timer.Del()
timer.runningLock.Lock()
timer.Del()
timer.runningLock.Unlock()
}
func (peer *Peer) timersActive() bool {
return peer.isRunning.Get() && peer.device != nil && peer.device.isUp.Get() && len(peer.device.peers.keyMap) > 0
}
func expiredRetransmitHandshake(peer *Peer) {
if peer.timers.handshakeAttempts > MaxTimerHandshakes {
peer.device.log.Debug.Printf("%s: Handshake did not complete after %d attempts, giving up\n", peer, MaxTimerHandshakes+2)
if peer.timersActive() {
peer.timers.sendKeepalive.Del()
}
/* We drop all packets without a keypair and don't try again,
* if we try unsuccessfully for too long to make a handshake.
*/
peer.FlushNonceQueue()
/* We set a timer for destroying any residue that might be left
* of a partial exchange.
*/
if peer.timersActive() && !peer.timers.zeroKeyMaterial.isPending {
peer.timers.zeroKeyMaterial.Mod(RejectAfterTime * 3)
}
} else {
peer.timers.handshakeAttempts++
peer.device.log.Debug.Printf("%s: Handshake did not complete after %d seconds, retrying (try %d)\n", peer, int(RekeyTimeout.Seconds()), peer.timers.handshakeAttempts+1)
/* We clear the endpoint address src address, in case this is the cause of trouble. */
peer.mutex.Lock()
if peer.endpoint != nil {
peer.endpoint.ClearSrc()
}
peer.mutex.Unlock()
peer.SendHandshakeInitiation(true)
}
}
func expiredSendKeepalive(peer *Peer) {
peer.SendKeepalive()
if peer.timers.needAnotherKeepalive {
peer.timers.needAnotherKeepalive = false
if peer.timersActive() {
peer.timers.sendKeepalive.Mod(KeepaliveTimeout)
}
}
}
func expiredNewHandshake(peer *Peer) {
peer.device.log.Debug.Printf("%s: Retrying handshake because we stopped hearing back after %d seconds\n", peer, int((KeepaliveTimeout + RekeyTimeout).Seconds()))
/* We clear the endpoint address src address, in case this is the cause of trouble. */
peer.mutex.Lock()
if peer.endpoint != nil {
peer.endpoint.ClearSrc()
}
peer.mutex.Unlock()
peer.SendHandshakeInitiation(false)
}
func expiredZeroKeyMaterial(peer *Peer) {
peer.device.log.Debug.Printf(":%s Removing all keys, since we haven't received a new one in %d seconds\n", peer, int((RejectAfterTime * 3).Seconds()))
peer.ZeroAndFlushAll()
}
func expiredPersistentKeepalive(peer *Peer) {
if peer.persistentKeepaliveInterval > 0 {
peer.SendKeepalive()
}
}
/* Should be called after an authenticated data packet is sent. */
func (peer *Peer) timersDataSent() {
if peer.timersActive() && !peer.timers.newHandshake.isPending {
peer.timers.newHandshake.Mod(KeepaliveTimeout + RekeyTimeout)
}
}
/* Should be called after an authenticated data packet is received. */
func (peer *Peer) timersDataReceived() {
if peer.timersActive() {
if !peer.timers.sendKeepalive.isPending {
peer.timers.sendKeepalive.Mod(KeepaliveTimeout)
} else {
peer.timers.needAnotherKeepalive = true
}
}
}
/* Should be called after any type of authenticated packet is sent -- keepalive, data, or handshake. */
func (peer *Peer) timersAnyAuthenticatedPacketSent() {
if peer.timersActive() {
peer.timers.sendKeepalive.Del()
}
}
/* Should be called after any type of authenticated packet is received -- keepalive, data, or handshake. */
func (peer *Peer) timersAnyAuthenticatedPacketReceived() {
if peer.timersActive() {
peer.timers.newHandshake.Del()
}
}
/* Should be called after a handshake initiation message is sent. */
func (peer *Peer) timersHandshakeInitiated() {
if peer.timersActive() {
peer.timers.retransmitHandshake.Mod(RekeyTimeout + time.Millisecond*time.Duration(rand.Int31n(RekeyTimeoutJitterMaxMs)))
}
}
/* Should be called after a handshake response message is received and processed or when getting key confirmation via the first data message. */
func (peer *Peer) timersHandshakeComplete() {
if peer.timersActive() {
peer.timers.retransmitHandshake.Del()
}
peer.timers.handshakeAttempts = 0
peer.timers.sentLastMinuteHandshake = false
atomic.StoreInt64(&peer.stats.lastHandshakeNano, time.Now().UnixNano())
}
/* Should be called after an ephemeral key is created, which is before sending a handshake response or after receiving a handshake response. */
func (peer *Peer) timersSessionDerived() {
if peer.timersActive() {
peer.timers.zeroKeyMaterial.Mod(RejectAfterTime * 3)
}
}
/* Should be called before a packet with authentication -- keepalive, data, or handshake -- is sent, or after one is received. */
func (peer *Peer) timersAnyAuthenticatedPacketTraversal() {
if peer.persistentKeepaliveInterval > 0 && peer.timersActive() {
peer.timers.persistentKeepalive.Mod(time.Duration(peer.persistentKeepaliveInterval) * time.Second)
}
}
func (peer *Peer) timersInit() {
peer.timers.retransmitHandshake = peer.NewTimer(expiredRetransmitHandshake)
peer.timers.sendKeepalive = peer.NewTimer(expiredSendKeepalive)
peer.timers.newHandshake = peer.NewTimer(expiredNewHandshake)
peer.timers.zeroKeyMaterial = peer.NewTimer(expiredZeroKeyMaterial)
peer.timers.persistentKeepalive = peer.NewTimer(expiredPersistentKeepalive)
peer.timers.handshakeAttempts = 0
peer.timers.sentLastMinuteHandshake = false
peer.timers.needAnotherKeepalive = false
}
func (peer *Peer) timersStop() {
peer.timers.retransmitHandshake.DelSync()
peer.timers.sendKeepalive.DelSync()
peer.timers.newHandshake.DelSync()
peer.timers.zeroKeyMaterial.DelSync()
peer.timers.persistentKeepalive.DelSync()
}
|
