pex: improve keepalive handling

Whenever idle time exceeds keepalive time, ping up to once
every 1+keepalive/2 interval. Avoids spuriously treating a peer as
disconnected.

Signed-off-by: Felix Fietkau <nbd@nbd.name>

3 files changed, 5 insertions, 4 deletions

diff --git a/host.h b/host.h
index a63a60b..c678046 100644
--- a/host.h
+++ b/host.h
@@ -30,7 +30,6 @@ struct network_peer {
 		bool connected;
 		bool handshake;
 		bool has_local_ep_addr;
-		bool pinged;
 		union network_addr local_ep_addr;
 		union network_endpoint endpoint;
 
@@ -43,6 +42,7 @@ struct network_peer {
 		uint64_t last_request;
 		uint64_t last_query_sent;
 
+		int ping_wait;
 		int last_handshake_diff;
 		int idle;
 		int num_net_queries;
diff --git a/pex.c b/pex.c
index db143fc..cc374af 100644
--- a/pex.c
+++ b/pex.c
@@ -389,12 +389,12 @@ network_pex_query_hosts(struct network *net)
 static void
 network_pex_send_ping(struct network *net, struct network_peer *peer)
 {
-	if (peer->state.pinged || !peer->state.endpoint.sa.sa_family)
+	if (peer->state.ping_wait > 0 || !peer->state.endpoint.sa.sa_family)
 		return;
 
 	pex_msg_init(net, PEX_MSG_PING);
 	pex_msg_send(net, peer);
-	peer->state.pinged = true;
+	peer->state.ping_wait = 1 + net->net_config.keepalive / 2;
 }
 
 static void
diff --git a/wg.c b/wg.c
index 74e8aae..61554bc 100644
--- a/wg.c
+++ b/wg.c
@@ -52,6 +52,8 @@ struct network_peer *wg_peer_update_start(struct network *net, const uint8_t *ke
 
 	peer->state.handshake = false;
 	peer->state.idle++;
+	if (peer->state.ping_wait > 0)
+		peer->state.ping_wait--;
 	if (peer->state.idle >= 2 * net->net_config.keepalive)
 		wg_peer_set_connected(net, peer, false);
 	if (peer->state.idle > net->net_config.keepalive)
@@ -80,7 +82,6 @@ void wg_peer_set_last_handshake(struct network *net, struct network_peer *peer,
 		if (peer->state.idle > sec)
 			peer->state.idle = sec;
 		wg_peer_set_connected(net, peer, true);
-		peer->state.pinged = false;
 	}
 }