drivers/net/wireguard/queueing.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
   4  */
   5
   6 #ifndef _WG_QUEUEING_H
   7 #define _WG_QUEUEING_H
   8
   9 #include "peer.h"
  10 #include <linux/types.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/ip.h>
  13 #include <linux/ipv6.h>
  14 #include <net/ip_tunnels.h>
  15
  16 struct wg_device;
  17 struct wg_peer;
  18 struct multicore_worker;
  19 struct crypt_queue;
  20 struct sk_buff;
  21
  22 /* queueing.c APIs: */
  23 int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function,
  24                          bool multicore, unsigned int len);
  25 void wg_packet_queue_free(struct crypt_queue *queue, bool multicore);
  26 struct multicore_worker __percpu *
  27 wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr);
  28
  29 /* receive.c APIs: */
  30 void wg_packet_receive(struct wg_device *wg, struct sk_buff *skb);
  31 void wg_packet_handshake_receive_worker(struct work_struct *work);
  32 /* NAPI poll function: */
  33 int wg_packet_rx_poll(struct napi_struct *napi, int budget);
  34 /* Workqueue worker: */
  35 void wg_packet_decrypt_worker(struct work_struct *work);
  36
  37 /* send.c APIs: */
  38 void wg_packet_send_queued_handshake_initiation(struct wg_peer *peer,
  39                                                 bool is_retry);
  40 void wg_packet_send_handshake_response(struct wg_peer *peer);
  41 void wg_packet_send_handshake_cookie(struct wg_device *wg,
  42                                      struct sk_buff *initiating_skb,
  43                                      __le32 sender_index);
  44 void wg_packet_send_keepalive(struct wg_peer *peer);
  45 void wg_packet_purge_staged_packets(struct wg_peer *peer);
  46 void wg_packet_send_staged_packets(struct wg_peer *peer);
  47 /* Workqueue workers: */
  48 void wg_packet_handshake_send_worker(struct work_struct *work);
  49 void wg_packet_tx_worker(struct work_struct *work);
  50 void wg_packet_encrypt_worker(struct work_struct *work);
  51
  52 enum packet_state {
  53         PACKET_STATE_UNCRYPTED,
  54         PACKET_STATE_CRYPTED,
  55         PACKET_STATE_DEAD
  56 };
  57
  58 struct packet_cb {
  59         u64 nonce;
  60         struct noise_keypair *keypair;
  61         atomic_t state;
  62         u32 mtu;
  63         u8 ds;
  64 };
  65
  66 #define PACKET_CB(skb) ((struct packet_cb *)((skb)->cb))
  67 #define PACKET_PEER(skb) (PACKET_CB(skb)->keypair->entry.peer)
  68
  69 static inline bool wg_check_packet_protocol(struct sk_buff *skb)
  70 {
  71         __be16 real_protocol = ip_tunnel_parse_protocol(skb);
  72         return real_protocol && skb->protocol == real_protocol;
  73 }
  74
  75 static inline void wg_reset_packet(struct sk_buff *skb, bool encapsulating)
  76 {
  77         u8 l4_hash = skb->l4_hash;
  78         u8 sw_hash = skb->sw_hash;
  79         u32 hash = skb->hash;
  80         skb_scrub_packet(skb, true);
  81         memset(&skb->headers_start, 0,
  82                offsetof(struct sk_buff, headers_end) -
  83                        offsetof(struct sk_buff, headers_start));
  84         if (encapsulating) {
  85                 skb->l4_hash = l4_hash;
  86                 skb->sw_hash = sw_hash;
  87                 skb->hash = hash;
  88         }
  89         skb->queue_mapping = 0;
  90         skb->nohdr = 0;
  91         skb->peeked = 0;
  92         skb->mac_len = 0;
  93         skb->dev = NULL;
  94 #ifdef CONFIG_NET_SCHED
  95         skb->tc_index = 0;
  96 #endif
  97         skb_reset_redirect(skb);
  98         skb->hdr_len = skb_headroom(skb);
  99         skb_reset_mac_header(skb);
 100         skb_reset_network_header(skb);
 101         skb_reset_transport_header(skb);
 102         skb_probe_transport_header(skb);
 103         skb_reset_inner_headers(skb);
 104 }
 105
 106 static inline int wg_cpumask_choose_online(int *stored_cpu, unsigned int id)
 107 {
 108         unsigned int cpu = *stored_cpu, cpu_index, i;
 109
 110         if (unlikely(cpu == nr_cpumask_bits ||
 111                      !cpumask_test_cpu(cpu, cpu_online_mask))) {
 112                 cpu_index = id % cpumask_weight(cpu_online_mask);
 113                 cpu = cpumask_first(cpu_online_mask);
 114                 for (i = 0; i < cpu_index; ++i)
 115                         cpu = cpumask_next(cpu, cpu_online_mask);
 116                 *stored_cpu = cpu;
 117         }
 118         return cpu;
 119 }
 120
 121 /* This function is racy, in the sense that next is unlocked, so it could return
 122  * the same CPU twice. A race-free version of this would be to instead store an
 123  * atomic sequence number, do an increment-and-return, and then iterate through
 124  * every possible CPU until we get to that index -- choose_cpu. However that's
 125  * a bit slower, and it doesn't seem like this potential race actually
 126  * introduces any performance loss, so we live with it.
 127  */
 128 static inline int wg_cpumask_next_online(int *next)
 129 {
 130         int cpu = *next;
 131
 132         while (unlikely(!cpumask_test_cpu(cpu, cpu_online_mask)))
 133                 cpu = cpumask_next(cpu, cpu_online_mask) % nr_cpumask_bits;
 134         *next = cpumask_next(cpu, cpu_online_mask) % nr_cpumask_bits;
 135         return cpu;
 136 }
 137
 138 static inline int wg_queue_enqueue_per_device_and_peer(
 139         struct crypt_queue *device_queue, struct crypt_queue *peer_queue,
 140         struct sk_buff *skb, struct workqueue_struct *wq, int *next_cpu)
 141 {
 142         int cpu;
 143
 144         atomic_set_release(&PACKET_CB(skb)->state, PACKET_STATE_UNCRYPTED);
 145         /* We first queue this up for the peer ingestion, but the consumer
 146          * will wait for the state to change to CRYPTED or DEAD before.
 147          */
 148         if (unlikely(ptr_ring_produce_bh(&peer_queue->ring, skb)))
 149                 return -ENOSPC;
 150         /* Then we queue it up in the device queue, which consumes the
 151          * packet as soon as it can.
 152          */
 153         cpu = wg_cpumask_next_online(next_cpu);
 154         if (unlikely(ptr_ring_produce_bh(&device_queue->ring, skb)))
 155                 return -EPIPE;
 156         queue_work_on(cpu, wq, &per_cpu_ptr(device_queue->worker, cpu)->work);
 157         return 0;
 158 }
 159
 160 static inline void wg_queue_enqueue_per_peer(struct crypt_queue *queue,
 161                                              struct sk_buff *skb,
 162                                              enum packet_state state)
 163 {
 164         /* We take a reference, because as soon as we call atomic_set, the
 165          * peer can be freed from below us.
 166          */
 167         struct wg_peer *peer = wg_peer_get(PACKET_PEER(skb));
 168
 169         atomic_set_release(&PACKET_CB(skb)->state, state);
 170         queue_work_on(wg_cpumask_choose_online(&peer->serial_work_cpu,
 171                                                peer->internal_id),
 172                       peer->device->packet_crypt_wq, &queue->work);
 173         wg_peer_put(peer);
 174 }
 175
 176 static inline void wg_queue_enqueue_per_peer_napi(struct sk_buff *skb,
 177                                                   enum packet_state state)
 178 {
 179         /* We take a reference, because as soon as we call atomic_set, the
 180          * peer can be freed from below us.
 181          */
 182         struct wg_peer *peer = wg_peer_get(PACKET_PEER(skb));
 183
 184         atomic_set_release(&PACKET_CB(skb)->state, state);
 185         napi_schedule(&peer->napi);
 186         wg_peer_put(peer);
 187 }
 188
 189 #ifdef DEBUG
 190 bool wg_packet_counter_selftest(void);
 191 #endif
 192
 193 #endif /* _WG_QUEUEING_H */