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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.4 */5 6#include "timers.h"7#include "device.h"8#include "peer.h"9#include "queueing.h"10#include "socket.h"11 12/*13 * - Timer for retransmitting the handshake if we don't hear back after14 * `REKEY_TIMEOUT + jitter` ms.15 *16 * - Timer for sending empty packet if we have received a packet but after have17 * not sent one for `KEEPALIVE_TIMEOUT` ms.18 *19 * - Timer for initiating new handshake if we have sent a packet but after have20 * not received one (even empty) for `(KEEPALIVE_TIMEOUT + REKEY_TIMEOUT) +21 * jitter` ms.22 *23 * - Timer for zeroing out all ephemeral keys after `(REJECT_AFTER_TIME * 3)` ms24 * if no new keys have been received.25 *26 * - Timer for, if enabled, sending an empty authenticated packet every user-27 * specified seconds.28 */29 30static inline void mod_peer_timer(struct wg_peer *peer,31 struct timer_list *timer,32 unsigned long expires)33{34 rcu_read_lock_bh();35 if (likely(netif_running(peer->device->dev) &&36 !READ_ONCE(peer->is_dead)))37 mod_timer(timer, expires);38 rcu_read_unlock_bh();39}40 41static void wg_expired_retransmit_handshake(struct timer_list *timer)42{43 struct wg_peer *peer = from_timer(peer, timer,44 timer_retransmit_handshake);45 46 if (peer->timer_handshake_attempts > MAX_TIMER_HANDSHAKES) {47 pr_debug("%s: Handshake for peer %llu (%pISpfsc) did not complete after %d attempts, giving up\n",48 peer->device->dev->name, peer->internal_id,49 &peer->endpoint.addr, (int)MAX_TIMER_HANDSHAKES + 2);50 51 del_timer(&peer->timer_send_keepalive);52 /* We drop all packets without a keypair and don't try again,53 * if we try unsuccessfully for too long to make a handshake.54 */55 wg_packet_purge_staged_packets(peer);56 57 /* We set a timer for destroying any residue that might be left58 * of a partial exchange.59 */60 if (!timer_pending(&peer->timer_zero_key_material))61 mod_peer_timer(peer, &peer->timer_zero_key_material,62 jiffies + REJECT_AFTER_TIME * 3 * HZ);63 } else {64 ++peer->timer_handshake_attempts;65 pr_debug("%s: Handshake for peer %llu (%pISpfsc) did not complete after %d seconds, retrying (try %d)\n",66 peer->device->dev->name, peer->internal_id,67 &peer->endpoint.addr, (int)REKEY_TIMEOUT,68 peer->timer_handshake_attempts + 1);69 70 /* We clear the endpoint address src address, in case this is71 * the cause of trouble.72 */73 wg_socket_clear_peer_endpoint_src(peer);74 75 wg_packet_send_queued_handshake_initiation(peer, true);76 }77}78 79static void wg_expired_send_keepalive(struct timer_list *timer)80{81 struct wg_peer *peer = from_timer(peer, timer, timer_send_keepalive);82 83 wg_packet_send_keepalive(peer);84 if (peer->timer_need_another_keepalive) {85 peer->timer_need_another_keepalive = false;86 mod_peer_timer(peer, &peer->timer_send_keepalive,87 jiffies + KEEPALIVE_TIMEOUT * HZ);88 }89}90 91static void wg_expired_new_handshake(struct timer_list *timer)92{93 struct wg_peer *peer = from_timer(peer, timer, timer_new_handshake);94 95 pr_debug("%s: Retrying handshake with peer %llu (%pISpfsc) because we stopped hearing back after %d seconds\n",96 peer->device->dev->name, peer->internal_id,97 &peer->endpoint.addr, (int)(KEEPALIVE_TIMEOUT + REKEY_TIMEOUT));98 /* We clear the endpoint address src address, in case this is the cause99 * of trouble.100 */101 wg_socket_clear_peer_endpoint_src(peer);102 wg_packet_send_queued_handshake_initiation(peer, false);103}104 105static void wg_expired_zero_key_material(struct timer_list *timer)106{107 struct wg_peer *peer = from_timer(peer, timer, timer_zero_key_material);108 109 rcu_read_lock_bh();110 if (!READ_ONCE(peer->is_dead)) {111 wg_peer_get(peer);112 if (!queue_work(peer->device->handshake_send_wq,113 &peer->clear_peer_work))114 /* If the work was already on the queue, we want to drop115 * the extra reference.116 */117 wg_peer_put(peer);118 }119 rcu_read_unlock_bh();120}121 122static void wg_queued_expired_zero_key_material(struct work_struct *work)123{124 struct wg_peer *peer = container_of(work, struct wg_peer,125 clear_peer_work);126 127 pr_debug("%s: Zeroing out all keys for peer %llu (%pISpfsc), since we haven't received a new one in %d seconds\n",128 peer->device->dev->name, peer->internal_id,129 &peer->endpoint.addr, (int)REJECT_AFTER_TIME * 3);130 wg_noise_handshake_clear(&peer->handshake);131 wg_noise_keypairs_clear(&peer->keypairs);132 wg_peer_put(peer);133}134 135static void wg_expired_send_persistent_keepalive(struct timer_list *timer)136{137 struct wg_peer *peer = from_timer(peer, timer,138 timer_persistent_keepalive);139 140 if (likely(peer->persistent_keepalive_interval))141 wg_packet_send_keepalive(peer);142}143 144/* Should be called after an authenticated data packet is sent. */145void wg_timers_data_sent(struct wg_peer *peer)146{147 if (!timer_pending(&peer->timer_new_handshake))148 mod_peer_timer(peer, &peer->timer_new_handshake,149 jiffies + (KEEPALIVE_TIMEOUT + REKEY_TIMEOUT) * HZ +150 get_random_u32_below(REKEY_TIMEOUT_JITTER_MAX_JIFFIES));151}152 153/* Should be called after an authenticated data packet is received. */154void wg_timers_data_received(struct wg_peer *peer)155{156 if (likely(netif_running(peer->device->dev))) {157 if (!timer_pending(&peer->timer_send_keepalive))158 mod_peer_timer(peer, &peer->timer_send_keepalive,159 jiffies + KEEPALIVE_TIMEOUT * HZ);160 else161 peer->timer_need_another_keepalive = true;162 }163}164 165/* Should be called after any type of authenticated packet is sent, whether166 * keepalive, data, or handshake.167 */168void wg_timers_any_authenticated_packet_sent(struct wg_peer *peer)169{170 del_timer(&peer->timer_send_keepalive);171}172 173/* Should be called after any type of authenticated packet is received, whether174 * keepalive, data, or handshake.175 */176void wg_timers_any_authenticated_packet_received(struct wg_peer *peer)177{178 del_timer(&peer->timer_new_handshake);179}180 181/* Should be called after a handshake initiation message is sent. */182void wg_timers_handshake_initiated(struct wg_peer *peer)183{184 mod_peer_timer(peer, &peer->timer_retransmit_handshake,185 jiffies + REKEY_TIMEOUT * HZ +186 get_random_u32_below(REKEY_TIMEOUT_JITTER_MAX_JIFFIES));187}188 189/* Should be called after a handshake response message is received and processed190 * or when getting key confirmation via the first data message.191 */192void wg_timers_handshake_complete(struct wg_peer *peer)193{194 del_timer(&peer->timer_retransmit_handshake);195 peer->timer_handshake_attempts = 0;196 peer->sent_lastminute_handshake = false;197 ktime_get_real_ts64(&peer->walltime_last_handshake);198}199 200/* Should be called after an ephemeral key is created, which is before sending a201 * handshake response or after receiving a handshake response.202 */203void wg_timers_session_derived(struct wg_peer *peer)204{205 mod_peer_timer(peer, &peer->timer_zero_key_material,206 jiffies + REJECT_AFTER_TIME * 3 * HZ);207}208 209/* Should be called before a packet with authentication, whether210 * keepalive, data, or handshakem is sent, or after one is received.211 */212void wg_timers_any_authenticated_packet_traversal(struct wg_peer *peer)213{214 if (peer->persistent_keepalive_interval)215 mod_peer_timer(peer, &peer->timer_persistent_keepalive,216 jiffies + peer->persistent_keepalive_interval * HZ);217}218 219void wg_timers_init(struct wg_peer *peer)220{221 timer_setup(&peer->timer_retransmit_handshake,222 wg_expired_retransmit_handshake, 0);223 timer_setup(&peer->timer_send_keepalive, wg_expired_send_keepalive, 0);224 timer_setup(&peer->timer_new_handshake, wg_expired_new_handshake, 0);225 timer_setup(&peer->timer_zero_key_material,226 wg_expired_zero_key_material, 0);227 timer_setup(&peer->timer_persistent_keepalive,228 wg_expired_send_persistent_keepalive, 0);229 INIT_WORK(&peer->clear_peer_work, wg_queued_expired_zero_key_material);230 peer->timer_handshake_attempts = 0;231 peer->sent_lastminute_handshake = false;232 peer->timer_need_another_keepalive = false;233}234 235void wg_timers_stop(struct wg_peer *peer)236{237 timer_delete_sync(&peer->timer_retransmit_handshake);238 timer_delete_sync(&peer->timer_send_keepalive);239 timer_delete_sync(&peer->timer_new_handshake);240 timer_delete_sync(&peer->timer_zero_key_material);241 timer_delete_sync(&peer->timer_persistent_keepalive);242 flush_work(&peer->clear_peer_work);243}244