diff options
| -rw-r--r-- | src/peer.h | 2 | ||||
| -rw-r--r-- | src/receive.c | 2 | ||||
| -rw-r--r-- | src/send.c | 19 | ||||
| -rw-r--r-- | src/timers.c | 33 | ||||
| -rw-r--r-- | src/timers.h | 2 |
5 files changed, 50 insertions, 8 deletions
@@ -29,7 +29,7 @@ struct wireguard_peer { struct cookie latest_cookie; struct hlist_node pubkey_hash; uint64_t rx_bytes, tx_bytes; - struct timer_list timer_retransmit_handshake, timer_send_keepalive, timer_new_handshake, timer_kill_ephemerals, timer_persistent_keepalive; + struct timer_list timer_retransmit_handshake, timer_delay_handshake, timer_send_keepalive, timer_new_handshake, timer_kill_ephemerals, timer_persistent_keepalive; unsigned int timer_handshake_attempts; unsigned long persistent_keepalive_interval; bool timer_need_another_keepalive; diff --git a/src/receive.c b/src/receive.c index 54e74b0..58a0086 100644 --- a/src/receive.c +++ b/src/receive.c @@ -123,6 +123,7 @@ static void receive_handshake_packet(struct wireguard_device *wg, void *data, si return; } net_dbg_ratelimited("Receiving handshake initiation from peer %Lu (%pISpfsc)\n", peer->internal_id, &addr); + timers_handshake_received(peer); update_latest_addr(peer, skb); packet_send_handshake_response(peer); break; @@ -138,6 +139,7 @@ static void receive_handshake_packet(struct wireguard_device *wg, void *data, si return; } net_dbg_ratelimited("Receiving handshake response from peer %Lu (%pISpfsc)\n", peer->internal_id, &addr); + timers_handshake_received(peer); if (noise_handshake_begin_session(&peer->handshake, &peer->keypairs, true)) { timers_ephemeral_key_created(peer); timers_handshake_complete(peer); @@ -90,7 +90,6 @@ void packet_send_handshake_cookie(struct wireguard_device *wg, struct sk_buff *i static inline void keep_key_fresh(struct wireguard_peer *peer) { struct noise_keypair *keypair; - unsigned long rekey_after_time = REKEY_AFTER_TIME; rcu_read_lock(); keypair = rcu_dereference(peer->keypairs.current_keypair); @@ -99,14 +98,20 @@ static inline void keep_key_fresh(struct wireguard_peer *peer) return; } - /* We don't want both peers initiating a new handshake at the same time */ - if (!keypair->i_am_the_initiator) - rekey_after_time += REKEY_TIMEOUT / 2 + REKEY_TIMEOUT * 2; - if (atomic64_read(&keypair->sending.counter.counter) > REKEY_AFTER_MESSAGES || - time_is_before_eq_jiffies64(keypair->sending.birthdate + rekey_after_time)) { + time_is_before_eq_jiffies64(keypair->sending.birthdate + REKEY_AFTER_TIME)) { rcu_read_unlock(); - ratelimit_packet_send_handshake_initiation(peer); + /* The initiator can try it immediately, but the responder has to wait a bit, + * to prevent the thundering herd effect. */ + if (keypair->i_am_the_initiator) + ratelimit_packet_send_handshake_initiation(peer); + else { + /* If it's going to be dead soon, we rekey early. */ + if (time_is_before_eq_jiffies64(keypair->sending.birthdate + REJECT_AFTER_TIME - KEEPALIVE_TIMEOUT - REKEY_TIMEOUT)) + timers_delay_handshake(peer, REKEY_TIMEOUT / 2); + else /* Otherwise rekey at the usual staggered delay. */ + timers_delay_handshake(peer, REKEY_TIMEOUT / 2 + REKEY_TIMEOUT * 2); + } } else rcu_read_unlock(); } diff --git a/src/timers.c b/src/timers.c index 300becb..7002e54 100644 --- a/src/timers.c +++ b/src/timers.c @@ -11,6 +11,7 @@ * 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 + * Timer for starting a new handshake based on a delay */ /* This rounds the time down to the closest power of two of the closest quarter second. */ @@ -58,6 +59,12 @@ static void expired_new_handshake(unsigned long ptr) packet_queue_send_handshake_initiation(peer); } +static void expired_delay_handshake(unsigned long ptr) +{ + struct wireguard_peer *peer = (struct wireguard_peer *)ptr; + packet_queue_send_handshake_initiation(peer); +} + static void expired_kill_ephemerals(unsigned long ptr) { struct wireguard_peer *peer = (struct wireguard_peer *)ptr; @@ -119,20 +126,38 @@ void timers_any_authenticated_packet_received(struct wireguard_peer *peer) /* Should be called after a handshake initiation message is sent. */ void timers_handshake_initiated(struct wireguard_peer *peer) { + if (likely(peer->timer_delay_handshake.data)) + del_timer(&peer->timer_delay_handshake); 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 + HZ / 4)); } +/* Should be called after a handshake message of any kind is received. */ +void timers_handshake_received(struct wireguard_peer *peer) +{ + if (likely(peer->timer_delay_handshake.data)) + del_timer(&peer->timer_delay_handshake); +} + /* Should be called after a handshake response message is received and processed. */ void timers_handshake_complete(struct wireguard_peer *peer) { + if (likely(peer->timer_delay_handshake.data)) + del_timer(&peer->timer_delay_handshake); if (likely(peer->timer_retransmit_handshake.data)) del_timer(&peer->timer_retransmit_handshake); peer->timer_handshake_attempts = 0; } +/* Should be called in order to initiate a handshake a little bit in the future. */ +void timers_delay_handshake(struct wireguard_peer *peer, unsigned int delay) +{ + if (likely(peer->timer_delay_handshake.data) && !timer_pending(&peer->timer_delay_handshake)) + mod_timer(&peer->timer_delay_handshake, jiffies + delay); +} + /* 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) { @@ -154,6 +179,10 @@ void timers_init_peer(struct wireguard_peer *peer) peer->timer_retransmit_handshake.function = expired_retransmit_handshake; peer->timer_retransmit_handshake.data = (unsigned long)peer; + init_timer(&peer->timer_delay_handshake); + peer->timer_delay_handshake.function = expired_delay_handshake; + peer->timer_delay_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; @@ -179,6 +208,10 @@ void timers_uninit_peer(struct wireguard_peer *peer) del_timer(&peer->timer_retransmit_handshake); peer->timer_retransmit_handshake.data = 0; } + if (peer->timer_delay_handshake.data) { + del_timer(&peer->timer_delay_handshake); + peer->timer_delay_handshake.data = 0; + } if (peer->timer_send_keepalive.data) { del_timer(&peer->timer_send_keepalive); peer->timer_send_keepalive.data = 0; diff --git a/src/timers.h b/src/timers.h index b6f80fd..349bdab 100644 --- a/src/timers.h +++ b/src/timers.h @@ -13,7 +13,9 @@ void timers_data_sent(struct wireguard_peer *peer); void timers_data_received(struct wireguard_peer *peer); void timers_any_authenticated_packet_received(struct wireguard_peer *peer); void timers_handshake_initiated(struct wireguard_peer *peer); +void timers_handshake_received(struct wireguard_peer *peer); void timers_handshake_complete(struct wireguard_peer *peer); +void timers_delay_handshake(struct wireguard_peer *peer, unsigned int delay); void timers_ephemeral_key_created(struct wireguard_peer *peer); void timers_any_authenticated_packet_traversal(struct wireguard_peer *peer); |