drivers/net/wireguard/timers.c

Source file repositories/reference/linux-study-clean/drivers/net/wireguard/timers.c

File Facts

System
Linux kernel
Corpus path
drivers/net/wireguard/timers.c
Extension
.c
Size
8274 bytes
Lines
247
Domain
Driver Families
Bucket
drivers/net
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// 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 = timer_container_of(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);

		timer_delete(&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 = timer_container_of(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);
	}
}

Annotation

Implementation Notes