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
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#include "timers.h"
#include "device.h"
#include "peer.h"
#include "queueing.h"
#include "socket.h"
/*
* - Timer for retransmitting the handshake if we don't hear back after
* `REKEY_TIMEOUT + jitter` ms.
*
* - Timer for sending empty packet if we have received a packet but after have
* not sent one for `KEEPALIVE_TIMEOUT` ms.
*
* - Timer for initiating new handshake if we have sent a packet but after have
* not received one (even empty) for `(KEEPALIVE_TIMEOUT + REKEY_TIMEOUT)` ms.
*
* - Timer for zeroing out all ephemeral keys after `(REJECT_AFTER_TIME * 3)` ms
* if no new keys have been received.
*
* - Timer for, if enabled, sending an empty authenticated packet every user-
* specified seconds.
*/
static inline void mod_peer_timer(struct wg_peer *peer,
struct timer_list *timer,
unsigned long expires)
{
rcu_read_lock_bh();
if (likely(netif_running(peer->device->dev) &&
!READ_ONCE(peer->is_dead)))
mod_timer(timer, expires);
rcu_read_unlock_bh();
}
static void wg_expired_retransmit_handshake(struct timer_list *timer)
{
struct wg_peer *peer = from_timer(peer, timer,
timer_retransmit_handshake);
if (peer->timer_handshake_attempts > MAX_TIMER_HANDSHAKES) {
pr_debug("%s: Handshake for peer %llu (%pISpfsc) did not complete after %d attempts, giving up\n",
peer->device->dev->name, peer->internal_id,
&peer->endpoint.addr, MAX_TIMER_HANDSHAKES + 2);
del_timer(&peer->timer_send_keepalive);
/* We drop all packets without a keypair and don't try again,
* if we try unsuccessfully for too long to make a handshake.
*/
wg_packet_purge_staged_packets(peer);
/* We set a timer for destroying any residue that might be left
* of a partial exchange.
*/
if (!timer_pending(&peer->timer_zero_key_material))
mod_peer_timer(peer, &peer->timer_zero_key_material,
jiffies + REJECT_AFTER_TIME * 3 * HZ);
} else {
++peer->timer_handshake_attempts;
pr_debug("%s: Handshake for peer %llu (%pISpfsc) did not complete after %d seconds, retrying (try %d)\n",
peer->device->dev->name, peer->internal_id,
&peer->endpoint.addr, REKEY_TIMEOUT,
peer->timer_handshake_attempts + 1);
/* We clear the endpoint address src address, in case this is
* the cause of trouble.
*/
wg_socket_clear_peer_endpoint_src(peer);
wg_packet_send_queued_handshake_initiation(peer, true);
}
}
static void wg_expired_send_keepalive(struct timer_list *timer)
{
struct wg_peer *peer = from_timer(peer, timer, timer_send_keepalive);
wg_packet_send_keepalive(peer);
if (peer->timer_need_another_keepalive) {
peer->timer_need_another_keepalive = false;
mod_peer_timer(peer, &peer->timer_send_keepalive,
jiffies + KEEPALIVE_TIMEOUT * HZ);
}
}
static void wg_expired_new_handshake(struct timer_list *timer)
{
struct wg_peer *peer = from_timer(peer, timer, timer_new_handshake);
pr_debug("%s: Retrying handshake with peer %llu (%pISpfsc) because we stopped hearing back after %d seconds\n",
peer->device->dev->name, peer->internal_id,
&peer->endpoint.addr, KEEPALIVE_TIMEOUT + REKEY_TIMEOUT);
/* We clear the endpoint address src address, in case this is the cause
* of trouble.
*/
wg_socket_clear_peer_endpoint_src(peer);
wg_packet_send_queued_handshake_initiation(peer, false);
}
static void wg_expired_zero_key_material(struct timer_list *timer)
{
struct wg_peer *peer = from_timer(peer, timer, timer_zero_key_material);
rcu_read_lock_bh();
if (!READ_ONCE(peer->is_dead)) {
wg_peer_get(peer);
if (!queue_work(peer->device->handshake_send_wq,
&peer->clear_peer_work))
/* If the work was already on the queue, we want to drop
* the extra reference.
*/
wg_peer_put(peer);
}
rcu_read_unlock_bh();
}
static void wg_queued_expired_zero_key_material(struct work_struct *work)
{
struct wg_peer *peer = container_of(work, struct wg_peer,
clear_peer_work);
pr_debug("%s: Zeroing out all keys for peer %llu (%pISpfsc), since we haven't received a new one in %d seconds\n",
peer->device->dev->name, peer->internal_id,
&peer->endpoint.addr, REJECT_AFTER_TIME * 3);
wg_noise_handshake_clear(&peer->handshake);
wg_noise_keypairs_clear(&peer->keypairs);
wg_peer_put(peer);
}
static void wg_expired_send_persistent_keepalive(struct timer_list *timer)
{
struct wg_peer *peer = from_timer(peer, timer,
timer_persistent_keepalive);
if (likely(peer->persistent_keepalive_interval))
wg_packet_send_keepalive(peer);
}
/* Should be called after an authenticated data packet is sent. */
void wg_timers_data_sent(struct wg_peer *peer)
{
if (!timer_pending(&peer->timer_new_handshake))
mod_peer_timer(peer, &peer->timer_new_handshake,
jiffies + (KEEPALIVE_TIMEOUT + REKEY_TIMEOUT) * HZ);
}
/* Should be called after an authenticated data packet is received. */
void wg_timers_data_received(struct wg_peer *peer)
{
if (likely(netif_running(peer->device->dev))) {
if (!timer_pending(&peer->timer_send_keepalive))
mod_peer_timer(peer, &peer->timer_send_keepalive,
jiffies + KEEPALIVE_TIMEOUT * HZ);
else
peer->timer_need_another_keepalive = true;
}
}
/* Should be called after any type of authenticated packet is sent, whether
* keepalive, data, or handshake.
*/
void wg_timers_any_authenticated_packet_sent(struct wg_peer *peer)
{
del_timer(&peer->timer_send_keepalive);
}
/* Should be called after any type of authenticated packet is received, whether
* keepalive, data, or handshake.
*/
void wg_timers_any_authenticated_packet_received(struct wg_peer *peer)
{
del_timer(&peer->timer_new_handshake);
}
/* Should be called after a handshake initiation message is sent. */
void wg_timers_handshake_initiated(struct wg_peer *peer)
{
mod_peer_timer(peer, &peer->timer_retransmit_handshake,
jiffies + REKEY_TIMEOUT * HZ +
prandom_u32_max(REKEY_TIMEOUT_JITTER_MAX_JIFFIES));
}
/* Should be called after a handshake response message is received and processed
* or when getting key confirmation via the first data message.
*/
void wg_timers_handshake_complete(struct wg_peer *peer)
{
del_timer(&peer->timer_retransmit_handshake);
peer->timer_handshake_attempts = 0;
peer->sent_lastminute_handshake = false;
getnstimeofday(&peer->walltime_last_handshake);
}
/* Should be called after an ephemeral key is created, which is before sending a
* handshake response or after receiving a handshake response.
*/
void wg_timers_session_derived(struct wg_peer *peer)
{
mod_peer_timer(peer, &peer->timer_zero_key_material,
jiffies + REJECT_AFTER_TIME * 3 * HZ);
}
/* Should be called before a packet with authentication, whether
* keepalive, data, or handshakem is sent, or after one is received.
*/
void wg_timers_any_authenticated_packet_traversal(struct wg_peer *peer)
{
if (peer->persistent_keepalive_interval)
mod_peer_timer(peer, &peer->timer_persistent_keepalive,
jiffies + peer->persistent_keepalive_interval * HZ);
}
void wg_timers_init(struct wg_peer *peer)
{
timer_setup(&peer->timer_retransmit_handshake,
wg_expired_retransmit_handshake, 0);
timer_setup(&peer->timer_send_keepalive, wg_expired_send_keepalive, 0);
timer_setup(&peer->timer_new_handshake, wg_expired_new_handshake, 0);
timer_setup(&peer->timer_zero_key_material,
wg_expired_zero_key_material, 0);
timer_setup(&peer->timer_persistent_keepalive,
wg_expired_send_persistent_keepalive, 0);
INIT_WORK(&peer->clear_peer_work, wg_queued_expired_zero_key_material);
peer->timer_handshake_attempts = 0;
peer->sent_lastminute_handshake = false;
peer->timer_need_another_keepalive = false;
}
void wg_timers_stop(struct wg_peer *peer)
{
del_timer_sync(&peer->timer_retransmit_handshake);
del_timer_sync(&peer->timer_send_keepalive);
del_timer_sync(&peer->timer_new_handshake);
del_timer_sync(&peer->timer_zero_key_material);
del_timer_sync(&peer->timer_persistent_keepalive);
flush_work(&peer->clear_peer_work);
}
|
