diff options
Diffstat (limited to 'drivers/net/wireguard/timers.c')
| -rw-r--r-- | drivers/net/wireguard/timers.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/drivers/net/wireguard/timers.c b/drivers/net/wireguard/timers.c new file mode 100644 index 000000000..91f5d6d2d --- /dev/null +++ b/drivers/net/wireguard/timers.c @@ -0,0 +1,243 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 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) + + * jitter` 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, (int)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, (int)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, (int)(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, (int)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 + + prandom_u32_max(REKEY_TIMEOUT_JITTER_MAX_JIFFIES)); +} + +/* 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; + ktime_get_real_ts64(&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); +} |