Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 */
 
#include "peer.h"
#include "device.h"
#include "queueing.h"
#include "timers.h"
#include "peerlookup.h"
#include "noise.h"
 
#include <linux/kref.h>
#include <linux/lockdep.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
 
static struct kmem_cache *peer_cache;
static atomic64_t peer_counter = ATOMIC64_INIT(0);
 
struct wg_peer *wg_peer_create(struct wg_device *wg,
<------><------><------>       const u8 public_key[NOISE_PUBLIC_KEY_LEN],
<------><------><------>       const u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN])
{
<------>struct wg_peer *peer;
<------>int ret = -ENOMEM;
 
<------>lockdep_assert_held(&wg->device_update_lock);
 
<------>if (wg->num_peers >= MAX_PEERS_PER_DEVICE)
<------><------>return ERR_PTR(ret);
 
<------>peer = kmem_cache_zalloc(peer_cache, GFP_KERNEL);
<------>if (unlikely(!peer))
<------><------>return ERR_PTR(ret);
<------>if (unlikely(dst_cache_init(&peer->endpoint_cache, GFP_KERNEL)))
<------><------>goto err;
 
<------>peer->device = wg;
<------>wg_noise_handshake_init(&peer->handshake, &wg->static_identity,
<------><------><------><------>public_key, preshared_key, peer);
<------>peer->internal_id = atomic64_inc_return(&peer_counter);
<------>peer->serial_work_cpu = nr_cpumask_bits;
<------>wg_cookie_init(&peer->latest_cookie);
<------>wg_timers_init(peer);
<------>wg_cookie_checker_precompute_peer_keys(peer);
<------>spin_lock_init(&peer->keypairs.keypair_update_lock);
<------>INIT_WORK(&peer->transmit_handshake_work, wg_packet_handshake_send_worker);
<------>INIT_WORK(&peer->transmit_packet_work, wg_packet_tx_worker);
<------>wg_prev_queue_init(&peer->tx_queue);
<------>wg_prev_queue_init(&peer->rx_queue);
<------>rwlock_init(&peer->endpoint_lock);
<------>kref_init(&peer->refcount);
<------>skb_queue_head_init(&peer->staged_packet_queue);
<------>wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake);
<------>set_bit(NAPI_STATE_NO_BUSY_POLL, &peer->napi.state);
<------>netif_napi_add(wg->dev, &peer->napi, wg_packet_rx_poll,
<------><------>       NAPI_POLL_WEIGHT);
<------>napi_enable(&peer->napi);
<------>list_add_tail(&peer->peer_list, &wg->peer_list);
<------>INIT_LIST_HEAD(&peer->allowedips_list);
<------>wg_pubkey_hashtable_add(wg->peer_hashtable, peer);
<------>++wg->num_peers;
<------>pr_debug("%s: Peer %llu created\n", wg->dev->name, peer->internal_id);
<------>return peer;
 
err:
<------>kmem_cache_free(peer_cache, peer);
<------>return ERR_PTR(ret);
}
 
struct wg_peer *wg_peer_get_maybe_zero(struct wg_peer *peer)
{
<------>RCU_LOCKDEP_WARN(!rcu_read_lock_bh_held(),
<------><------><------> "Taking peer reference without holding the RCU read lock");
<------>if (unlikely(!peer || !kref_get_unless_zero(&peer->refcount)))
<------><------>return NULL;
<------>return peer;
}
 
static void peer_make_dead(struct wg_peer *peer)
{
<------>/* Remove from configuration-time lookup structures. */
<------>list_del_init(&peer->peer_list);
<------>wg_allowedips_remove_by_peer(&peer->device->peer_allowedips, peer,
<------><------><------><------>     &peer->device->device_update_lock);
<------>wg_pubkey_hashtable_remove(peer->device->peer_hashtable, peer);
 
<------>/* Mark as dead, so that we don't allow jumping contexts after. */
<------>WRITE_ONCE(peer->is_dead, true);
 
<------>/* The caller must now synchronize_net() for this to take effect. */
}
 
static void peer_remove_after_dead(struct wg_peer *peer)
{
<------>WARN_ON(!peer->is_dead);
 
<------>/* No more keypairs can be created for this peer, since is_dead protects
<------> * add_new_keypair, so we can now destroy existing ones.
<------> */
<------>wg_noise_keypairs_clear(&peer->keypairs);
 
<------>/* Destroy all ongoing timers that were in-flight at the beginning of
<------> * this function.
<------> */
<------>wg_timers_stop(peer);
 
<------>/* The transition between packet encryption/decryption queues isn't
<------> * guarded by is_dead, but each reference's life is strictly bounded by
<------> * two generations: once for parallel crypto and once for serial
<------> * ingestion, so we can simply flush twice, and be sure that we no
<------> * longer have references inside these queues.
<------> */
 
<------>/* a) For encrypt/decrypt. */
<------>flush_workqueue(peer->device->packet_crypt_wq);
<------>/* b.1) For send (but not receive, since that's napi). */
<------>flush_workqueue(peer->device->packet_crypt_wq);
<------>/* b.2.1) For receive (but not send, since that's wq). */
<------>napi_disable(&peer->napi);
<------>/* b.2.1) It's now safe to remove the napi struct, which must be done
<------> * here from process context.
<------> */
<------>netif_napi_del(&peer->napi);
 
<------>/* Ensure any workstructs we own (like transmit_handshake_work or
<------> * clear_peer_work) no longer are in use.
<------> */
<------>flush_workqueue(peer->device->handshake_send_wq);
 
<------>/* After the above flushes, a peer might still be active in a few
<------> * different contexts: 1) from xmit(), before hitting is_dead and
<------> * returning, 2) from wg_packet_consume_data(), before hitting is_dead
<------> * and returning, 3) from wg_receive_handshake_packet() after a point
<------> * where it has processed an incoming handshake packet, but where
<------> * all calls to pass it off to timers fails because of is_dead. We won't
<------> * have new references in (1) eventually, because we're removed from
<------> * allowedips; we won't have new references in (2) eventually, because
<------> * wg_index_hashtable_lookup will always return NULL, since we removed
<------> * all existing keypairs and no more can be created; we won't have new
<------> * references in (3) eventually, because we're removed from the pubkey
<------> * hash table, which allows for a maximum of one handshake response,
<------> * via the still-uncleared index hashtable entry, but not more than one,
<------> * and in wg_cookie_message_consume, the lookup eventually gets a peer
<------> * with a refcount of zero, so no new reference is taken.
<------> */
 
<------>--peer->device->num_peers;
<------>wg_peer_put(peer);
}
 
/* We have a separate "remove" function make sure that all active places where
 * a peer is currently operating will eventually come to an end and not pass
 * their reference onto another context.
 */
void wg_peer_remove(struct wg_peer *peer)
{
<------>if (unlikely(!peer))
<------><------>return;
<------>lockdep_assert_held(&peer->device->device_update_lock);
 
<------>peer_make_dead(peer);
<------>synchronize_net();
<------>peer_remove_after_dead(peer);
}
 
void wg_peer_remove_all(struct wg_device *wg)
{
<------>struct wg_peer *peer, *temp;
<------>LIST_HEAD(dead_peers);
 
<------>lockdep_assert_held(&wg->device_update_lock);
 
<------>/* Avoid having to traverse individually for each one. */
<------>wg_allowedips_free(&wg->peer_allowedips, &wg->device_update_lock);
 
<------>list_for_each_entry_safe(peer, temp, &wg->peer_list, peer_list) {
<------><------>peer_make_dead(peer);
<------><------>list_add_tail(&peer->peer_list, &dead_peers);
<------>}
<------>synchronize_net();
<------>list_for_each_entry_safe(peer, temp, &dead_peers, peer_list)
<------><------>peer_remove_after_dead(peer);
}
 
static void rcu_release(struct rcu_head *rcu)
{
<------>struct wg_peer *peer = container_of(rcu, struct wg_peer, rcu);
 
<------>dst_cache_destroy(&peer->endpoint_cache);
<------>WARN_ON(wg_prev_queue_peek(&peer->tx_queue) || wg_prev_queue_peek(&peer->rx_queue));
 
<------>/* The final zeroing takes care of clearing any remaining handshake key
<------> * material and other potentially sensitive information.
<------> */
<------>memzero_explicit(peer, sizeof(*peer));
<------>kmem_cache_free(peer_cache, peer);
}
 
static void kref_release(struct kref *refcount)
{
<------>struct wg_peer *peer = container_of(refcount, struct wg_peer, refcount);
 
<------>pr_debug("%s: Peer %llu (%pISpfsc) destroyed\n",
<------><------> peer->device->dev->name, peer->internal_id,
<------><------> &peer->endpoint.addr);
 
<------>/* Remove ourself from dynamic runtime lookup structures, now that the
<------> * last reference is gone.
<------> */
<------>wg_index_hashtable_remove(peer->device->index_hashtable,
<------><------><------><------>  &peer->handshake.entry);
 
<------>/* Remove any lingering packets that didn't have a chance to be
<------> * transmitted.
<------> */
<------>wg_packet_purge_staged_packets(peer);
 
<------>/* Free the memory used. */
<------>call_rcu(&peer->rcu, rcu_release);
}
 
void wg_peer_put(struct wg_peer *peer)
{
<------>if (unlikely(!peer))
<------><------>return;
<------>kref_put(&peer->refcount, kref_release);
}
 
int __init wg_peer_init(void)
{
<------>peer_cache = KMEM_CACHE(wg_peer, 0);
<------>return peer_cache ? 0 : -ENOMEM;
}
 
void wg_peer_uninit(void)
{
<------>kmem_cache_destroy(peer_cache);
}