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-rw-r--r--drivers/net/wireguard/timers.c241
1 files changed, 241 insertions, 0 deletions
diff --git a/drivers/net/wireguard/timers.c b/drivers/net/wireguard/timers.c
new file mode 100644
index 000000000000..7614c85fb23b
--- /dev/null
+++ b/drivers/net/wireguard/timers.c
@@ -0,0 +1,241 @@
+// 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)` 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;
+ 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);
+}