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/* Copyright (C) 2015-2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
#include "packets.h"
#include "timers.h"
#include "device.h"
#include "peer.h"
#include "socket.h"
#include "messages.h"
#include "cookie.h"
#include <linux/uio.h>
#include <linux/inetdevice.h>
#include <linux/socket.h>
#include <linux/jiffies.h>
#include <net/udp.h>
#include <net/sock.h>
static void packet_send_handshake_initiation(struct wireguard_peer *peer)
{
struct message_handshake_initiation packet;
down_write(&peer->handshake.lock);
if (!time_is_before_jiffies64(peer->last_sent_handshake + REKEY_TIMEOUT)) {
up_write(&peer->handshake.lock);
return; /* This function is rate limited. */
}
peer->last_sent_handshake = get_jiffies_64();
up_write(&peer->handshake.lock);
net_dbg_ratelimited("Sending handshake initiation to peer %Lu (%pISpfsc)\n", peer->internal_id, &peer->endpoint.addr);
if (noise_handshake_create_initiation(&packet, &peer->handshake)) {
cookie_add_mac_to_packet(&packet, sizeof(packet), peer);
timers_any_authenticated_packet_traversal(peer);
socket_send_buffer_to_peer(peer, &packet, sizeof(struct message_handshake_initiation), HANDSHAKE_DSCP);
timers_handshake_initiated(peer);
}
}
void packet_send_queued_handshakes(struct work_struct *work)
{
struct wireguard_peer *peer = container_of(work, struct wireguard_peer, transmit_handshake_work);
packet_send_handshake_initiation(peer);
peer_put(peer);
}
void packet_queue_handshake_initiation(struct wireguard_peer *peer)
{
/* First checking the timestamp here is just an optimization; it will
* be caught while properly locked inside the actual work queue. */
if (!time_is_before_jiffies64(peer->last_sent_handshake + REKEY_TIMEOUT))
return;
peer = peer_rcu_get(peer);
if (unlikely(!peer))
return;
/* Queues up calling packet_send_queued_handshakes(peer), where we do a peer_put(peer) after: */
if (!queue_work(peer->device->workqueue, &peer->transmit_handshake_work))
peer_put(peer); /* If the work was already queued, we want to drop the extra reference */
}
void packet_send_handshake_response(struct wireguard_peer *peer)
{
struct message_handshake_response packet;
net_dbg_ratelimited("Sending handshake response to peer %Lu (%pISpfsc)\n", peer->internal_id, &peer->endpoint.addr);
peer->last_sent_handshake = get_jiffies_64();
if (noise_handshake_create_response(&packet, &peer->handshake)) {
cookie_add_mac_to_packet(&packet, sizeof(packet), peer);
if (noise_handshake_begin_session(&peer->handshake, &peer->keypairs, false)) {
timers_ephemeral_key_created(peer);
timers_any_authenticated_packet_traversal(peer);
socket_send_buffer_to_peer(peer, &packet, sizeof(struct message_handshake_response), HANDSHAKE_DSCP);
}
}
}
void packet_send_handshake_cookie(struct wireguard_device *wg, struct sk_buff *initiating_skb, void *data, size_t data_len, __le32 sender_index)
{
struct message_handshake_cookie packet;
net_dbg_skb_ratelimited("Sending cookie response for denied handshake message for %pISpfsc\n", initiating_skb);
cookie_message_create(&packet, initiating_skb, data, data_len, sender_index, &wg->cookie_checker);
socket_send_buffer_as_reply_to_skb(wg, initiating_skb, &packet, sizeof(packet));
}
static inline void keep_key_fresh(struct wireguard_peer *peer)
{
struct noise_keypair *keypair;
bool send = false;
rcu_read_lock();
keypair = rcu_dereference(peer->keypairs.current_keypair);
if (likely(keypair && keypair->sending.is_valid) &&
(unlikely(atomic64_read(&keypair->sending.counter.counter) > REKEY_AFTER_MESSAGES) ||
(keypair->i_am_the_initiator && unlikely(time_is_before_eq_jiffies64(keypair->sending.birthdate + REKEY_AFTER_TIME)))))
send = true;
rcu_read_unlock();
if (send)
packet_queue_handshake_initiation(peer);
}
void packet_send_keepalive(struct wireguard_peer *peer)
{
struct sk_buff *skb;
if (!skb_queue_len(&peer->tx_packet_queue)) {
skb = alloc_skb(DATA_PACKET_HEAD_ROOM + MESSAGE_MINIMUM_LENGTH, GFP_ATOMIC);
if (unlikely(!skb))
return;
skb_reserve(skb, DATA_PACKET_HEAD_ROOM);
skb->dev = netdev_pub(peer->device);
skb_queue_tail(&peer->tx_packet_queue, skb);
net_dbg_ratelimited("Sending keepalive packet to peer %Lu (%pISpfsc)\n", peer->internal_id, &peer->endpoint.addr);
}
packet_send_queue(peer);
}
static void message_create_data_done(struct sk_buff_head *queue, struct wireguard_peer *peer)
{
struct sk_buff *skb, *tmp;
bool is_keepalive, data_sent = false;
timers_any_authenticated_packet_traversal(peer);
skb_queue_walk_safe(queue, skb, tmp) {
is_keepalive = skb->len == message_data_len(0);
if (likely(!socket_send_skb_to_peer(peer, skb, *(u8 *)skb->cb) && !is_keepalive))
data_sent = true;
}
if (likely(data_sent))
timers_data_sent(peer);
keep_key_fresh(peer);
if (unlikely(peer->need_resend_queue))
packet_send_queue(peer);
}
void packet_send_queue(struct wireguard_peer *peer)
{
struct sk_buff_head queue;
unsigned long flags;
peer->need_resend_queue = false;
/* Steal the current queue into our local one. */
skb_queue_head_init(&queue);
spin_lock_irqsave(&peer->tx_packet_queue.lock, flags);
skb_queue_splice_init(&peer->tx_packet_queue, &queue);
spin_unlock_irqrestore(&peer->tx_packet_queue.lock, flags);
if (unlikely(!skb_queue_len(&queue)))
return;
/* We submit it for encryption and sending. */
switch (packet_create_data(&queue, peer, message_create_data_done)) {
case 0:
break;
case -EBUSY:
/* EBUSY happens when the parallel workers are all filled up, in which
* case we should requeue everything. */
/* First, we mark that we should try to do this later, when existing
* jobs are done. */
peer->need_resend_queue = true;
/* We stick the remaining skbs from local_queue at the top of the peer's
* queue again, setting the top of local_queue to be the skb that begins
* the requeueing. */
spin_lock_irqsave(&peer->tx_packet_queue.lock, flags);
skb_queue_splice(&queue, &peer->tx_packet_queue);
spin_unlock_irqrestore(&peer->tx_packet_queue.lock, flags);
break;
case -ENOKEY:
/* ENOKEY means that we don't have a valid session for the peer, which
* means we should initiate a session, but after requeuing like above. */
spin_lock_irqsave(&peer->tx_packet_queue.lock, flags);
skb_queue_splice(&queue, &peer->tx_packet_queue);
spin_unlock_irqrestore(&peer->tx_packet_queue.lock, flags);
packet_queue_handshake_initiation(peer);
break;
default:
/* If we failed for any other reason, we want to just free the packets and
* forget about them. We do this unlocked, since we're the only ones with
* a reference to the local queue. */
__skb_queue_purge(&queue);
}
}
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