timers: only have initiator rekey

If it's time to rekey, and the responder sends a message, the initator
will begin the rekeying when sending his response message. In the worst
case, this response message will actually just be the keepalive. This
generally works well, with the one edge case of the message arriving
less than 10 seconds before key expiration, in which the keepalive is
not sufficient. In this case, we simply rehandshake immediately.

1 files changed, 0 insertions, 33 deletions

diff --git a/src/timers.c b/src/timers.c
index 7002e54..300becb 100644
--- a/src/timers.c
+++ b/src/timers.c
@@ -11,7 +11,6 @@
  * 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. */
@@ -59,12 +58,6 @@ 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;
@@ -126,38 +119,20 @@ 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)
 {
@@ -179,10 +154,6 @@ 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;
@@ -208,10 +179,6 @@ 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;