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
|
/* Copyright (C) 2015-2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
#include "timers.h"
#include "device.h"
#include "peer.h"
#include "packets.h"
/*
* Timer for retransmitting the handshake if we don't hear back after `REKEY_TIMEOUT` 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
*/
/* This rounds the time down to the closest power of two of the closest quarter second. */
static inline unsigned long slack_time(unsigned long time)
{
return time & ~(roundup_pow_of_two(HZ / 4) - 1);
}
#define peer_get_from_ptr(ptr) \
struct wireguard_peer *peer = peer_rcu_get((struct wireguard_peer *)ptr); \
if (unlikely(!peer)) \
return;
static void expired_retransmit_handshake(unsigned long ptr)
{
peer_get_from_ptr(ptr);
pr_debug("Handshake for peer %Lu (%pISpfsc) did not complete after %d seconds, retrying\n", peer->internal_id, &peer->endpoint.addr_storage, REKEY_TIMEOUT / HZ);
if (peer->timer_handshake_attempts > MAX_TIMER_HANDSHAKES) {
del_timer(&peer->timer_send_keepalive);
/* We remove all existing packets and don't try again,
* if we try unsuccessfully for too long to make a handshake. */
skb_queue_purge(&peer->tx_packet_queue);
/* We set a timer for destroying any residue that might be left
* of a partial exchange. */
if (likely(peer->timer_kill_ephemerals.data))
mod_timer(&peer->timer_kill_ephemerals, jiffies + (REJECT_AFTER_TIME * 3));
goto out;
}
/* We clear the endpoint address src address, in case this is the cause of trouble. */
socket_clear_peer_endpoint_src(peer);
packet_queue_handshake_initiation(peer);
++peer->timer_handshake_attempts;
out:
peer_put(peer);
}
static void expired_send_keepalive(unsigned long ptr)
{
peer_get_from_ptr(ptr);
packet_send_keepalive(peer);
if (peer->timer_need_another_keepalive) {
peer->timer_need_another_keepalive = false;
mod_timer(&peer->timer_send_keepalive, jiffies + KEEPALIVE_TIMEOUT);
}
peer_put(peer);
}
static void expired_new_handshake(unsigned long ptr)
{
peer_get_from_ptr(ptr);
pr_debug("Retrying handshake with peer %Lu (%pISpfsc) because we stopped hearing back after %d seconds\n", peer->internal_id, &peer->endpoint.addr_storage, (KEEPALIVE_TIMEOUT + REKEY_TIMEOUT) / HZ);
/* We clear the endpoint address src address, in case this is the cause of trouble. */
socket_clear_peer_endpoint_src(peer);
packet_queue_handshake_initiation(peer);
peer_put(peer);
}
static void expired_kill_ephemerals(unsigned long ptr)
{
peer_get_from_ptr(ptr);
if (!queue_work(peer->device->workqueue, &peer->clear_peer_work)) /* Takes our reference. */
peer_put(peer); /* If the work was already on the queue, we want to drop the extra reference */
}
static void queued_expired_kill_ephemerals(struct work_struct *work)
{
struct wireguard_peer *peer = container_of(work, struct wireguard_peer, clear_peer_work);
pr_debug("Zeroing out all keys for peer %Lu (%pISpfsc), since we haven't received a new one in %d seconds\n", peer->internal_id, &peer->endpoint.addr_storage, (REJECT_AFTER_TIME * 3) / HZ);
noise_handshake_clear(&peer->handshake);
noise_keypairs_clear(&peer->keypairs);
peer_put(peer);
}
static void expired_send_persistent_keepalive(unsigned long ptr)
{
peer_get_from_ptr(ptr);
if (likely(peer->persistent_keepalive_interval))
packet_send_keepalive(peer);
peer_put(peer);
}
/* Should be called after an authenticated data packet is sent. */
void timers_data_sent(struct wireguard_peer *peer)
{
if (likely(peer->timer_send_keepalive.data))
del_timer(&peer->timer_send_keepalive);
if (likely(peer->timer_new_handshake.data) && !timer_pending(&peer->timer_new_handshake))
mod_timer(&peer->timer_new_handshake, jiffies + KEEPALIVE_TIMEOUT + REKEY_TIMEOUT);
}
/* Should be called after an authenticated data packet is received. */
void timers_data_received(struct wireguard_peer *peer)
{
if (likely(peer->timer_send_keepalive.data) && !timer_pending(&peer->timer_send_keepalive))
mod_timer(&peer->timer_send_keepalive, jiffies + KEEPALIVE_TIMEOUT);
else
peer->timer_need_another_keepalive = true;
}
/* Should be called after any type of authenticated packet is received -- keepalive or data. */
void timers_any_authenticated_packet_received(struct wireguard_peer *peer)
{
if (likely(peer->timer_new_handshake.data))
del_timer(&peer->timer_new_handshake);
}
/* Should be called after a handshake initiation message is sent. */
void timers_handshake_initiated(struct wireguard_peer *peer)
{
if (likely(peer->timer_send_keepalive.data))
del_timer(&peer->timer_send_keepalive);
if (likely(peer->timer_retransmit_handshake.data))
mod_timer(&peer->timer_retransmit_handshake, slack_time(jiffies + REKEY_TIMEOUT + prandom_u32_max(REKEY_TIMEOUT_JITTER_MAX)));
}
/* Should be called after a handshake response message is received and processed. */
void timers_handshake_complete(struct wireguard_peer *peer)
{
if (likely(peer->timer_retransmit_handshake.data))
del_timer(&peer->timer_retransmit_handshake);
peer->timer_handshake_attempts = 0;
}
/* Should be called after an ephemeral key is created, which is before sending a handshake response or after receiving a handshake response. */
void timers_ephemeral_key_created(struct wireguard_peer *peer)
{
if (likely(peer->timer_kill_ephemerals.data))
mod_timer(&peer->timer_kill_ephemerals, jiffies + (REJECT_AFTER_TIME * 3));
do_gettimeofday(&peer->walltime_last_handshake);
}
/* Should be called before an packet with authentication -- data, keepalive, either handshake -- is sent, or after one is received. */
void timers_any_authenticated_packet_traversal(struct wireguard_peer *peer)
{
if (peer->persistent_keepalive_interval && likely(peer->timer_persistent_keepalive.data))
mod_timer(&peer->timer_persistent_keepalive, slack_time(jiffies + peer->persistent_keepalive_interval));
}
void timers_init_peer(struct wireguard_peer *peer)
{
init_timer(&peer->timer_retransmit_handshake);
peer->timer_retransmit_handshake.function = expired_retransmit_handshake;
peer->timer_retransmit_handshake.data = (unsigned long)peer;
init_timer(&peer->timer_send_keepalive);
peer->timer_send_keepalive.function = expired_send_keepalive;
peer->timer_send_keepalive.data = (unsigned long)peer;
init_timer(&peer->timer_new_handshake);
peer->timer_new_handshake.function = expired_new_handshake;
peer->timer_new_handshake.data = (unsigned long)peer;
init_timer(&peer->timer_kill_ephemerals);
peer->timer_kill_ephemerals.function = expired_kill_ephemerals;
peer->timer_kill_ephemerals.data = (unsigned long)peer;
init_timer(&peer->timer_persistent_keepalive);
peer->timer_persistent_keepalive.function = expired_send_persistent_keepalive;
peer->timer_persistent_keepalive.data = (unsigned long)peer;
INIT_WORK(&peer->clear_peer_work, queued_expired_kill_ephemerals);
}
void timers_uninit_peer(struct wireguard_peer *peer)
{
if (peer->timer_retransmit_handshake.data) {
del_timer(&peer->timer_retransmit_handshake);
peer->timer_retransmit_handshake.data = 0;
}
if (peer->timer_send_keepalive.data) {
del_timer(&peer->timer_send_keepalive);
peer->timer_send_keepalive.data = 0;
}
if (peer->timer_new_handshake.data) {
del_timer(&peer->timer_new_handshake);
peer->timer_new_handshake.data = 0;
}
if (peer->timer_kill_ephemerals.data) {
del_timer(&peer->timer_kill_ephemerals);
peer->timer_kill_ephemerals.data = 0;
}
if (peer->timer_persistent_keepalive.data) {
del_timer(&peer->timer_persistent_keepalive);
peer->timer_persistent_keepalive.data = 0;
}
}
void timers_uninit_peer_wait(struct wireguard_peer *peer)
{
timers_uninit_peer(peer);
flush_work(&peer->clear_peer_work);
}
|
