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 prev_queue;
21 struct sk_buff;
22
23 /* queueing.c APIs: */
24 int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function,
25 unsigned int len);
26 void wg_packet_queue_free(struct crypt_queue *queue, bool purge);
27 struct multicore_worker __percpu *
28 wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr);
29
30 /* receive.c APIs: */
31 void wg_packet_receive(struct wg_device *wg, struct sk_buff *skb);
32 void wg_packet_handshake_receive_worker(struct work_struct *work);
33 /* NAPI poll function: */
34 int wg_packet_rx_poll(struct napi_struct *napi, int budget);
35 /* Workqueue worker: */
36 void wg_packet_decrypt_worker(struct work_struct *work);
37
38 /* send.c APIs: */
39 void wg_packet_send_queued_handshake_initiation(struct wg_peer *peer,
40 bool is_retry);
41 void wg_packet_send_handshake_response(struct wg_peer *peer);
42 void wg_packet_send_handshake_cookie(struct wg_device *wg,
43 struct sk_buff *initiating_skb,
44 __le32 sender_index);
45 void wg_packet_send_keepalive(struct wg_peer *peer);
46 void wg_packet_purge_staged_packets(struct wg_peer *peer);
47 void wg_packet_send_staged_packets(struct wg_peer *peer);
48 /* Workqueue workers: */
49 void wg_packet_handshake_send_worker(struct work_struct *work);
50 void wg_packet_tx_worker(struct work_struct *work);
51 void wg_packet_encrypt_worker(struct work_struct *work);
52
53 enum packet_state {
54 PACKET_STATE_UNCRYPTED,
55 PACKET_STATE_CRYPTED,
56 PACKET_STATE_DEAD
57 };
58
59 struct packet_cb {
60 u64 nonce;
61 struct noise_keypair *keypair;
62 atomic_t state;
63 u32 mtu;
64 u8 ds;
65 };
66
67 #define PACKET_CB(skb) ((struct packet_cb *)((skb)->cb))
68 #define PACKET_PEER(skb) (PACKET_CB(skb)->keypair->entry.peer)
69
wg_check_packet_protocol(struct sk_buff * skb)70 static inline bool wg_check_packet_protocol(struct sk_buff *skb)
71 {
72 __be16 real_protocol = ip_tunnel_parse_protocol(skb);
73 return real_protocol && skb->protocol == real_protocol;
74 }
75
wg_reset_packet(struct sk_buff * skb,bool encapsulating)76 static inline void wg_reset_packet(struct sk_buff *skb, bool encapsulating)
77 {
78 u8 l4_hash = skb->l4_hash;
79 u8 sw_hash = skb->sw_hash;
80 u32 hash = skb->hash;
81 skb_scrub_packet(skb, true);
82 memset(&skb->headers, 0, sizeof(skb->headers));
83 if (encapsulating) {
84 skb->l4_hash = l4_hash;
85 skb->sw_hash = sw_hash;
86 skb->hash = hash;
87 }
88 skb->queue_mapping = 0;
89 skb->nohdr = 0;
90 skb->peeked = 0;
91 skb->mac_len = 0;
92 skb->dev = NULL;
93 #ifdef CONFIG_NET_SCHED
94 skb->tc_index = 0;
95 #endif
96 skb_reset_redirect(skb);
97 skb->hdr_len = skb_headroom(skb);
98 skb_reset_mac_header(skb);
99 skb_reset_network_header(skb);
100 skb_reset_transport_header(skb);
101 skb_probe_transport_header(skb);
102 skb_reset_inner_headers(skb);
103 }
104
wg_cpumask_choose_online(int * stored_cpu,unsigned int id)105 static inline int wg_cpumask_choose_online(int *stored_cpu, unsigned int id)
106 {
107 unsigned int cpu = *stored_cpu, cpu_index, i;
108
109 if (unlikely(cpu >= nr_cpu_ids ||
110 !cpumask_test_cpu(cpu, cpu_online_mask))) {
111 cpu_index = id % cpumask_weight(cpu_online_mask);
112 cpu = cpumask_first(cpu_online_mask);
113 for (i = 0; i < cpu_index; ++i)
114 cpu = cpumask_next(cpu, cpu_online_mask);
115 *stored_cpu = cpu;
116 }
117 return cpu;
118 }
119
120 /* This function is racy, in the sense that it's called while last_cpu is
121 * unlocked, so it could return the same CPU twice. Adding locking or using
122 * atomic sequence numbers is slower though, and the consequences of racing are
123 * harmless, so live with it.
124 */
wg_cpumask_next_online(int * last_cpu)125 static inline int wg_cpumask_next_online(int *last_cpu)
126 {
127 int cpu = cpumask_next(READ_ONCE(*last_cpu), cpu_online_mask);
128 if (cpu >= nr_cpu_ids)
129 cpu = cpumask_first(cpu_online_mask);
130 WRITE_ONCE(*last_cpu, cpu);
131 return cpu;
132 }
133
134 void wg_prev_queue_init(struct prev_queue *queue);
135
136 /* Multi producer */
137 bool wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb);
138
139 /* Single consumer */
140 struct sk_buff *wg_prev_queue_dequeue(struct prev_queue *queue);
141
142 /* Single consumer */
wg_prev_queue_peek(struct prev_queue * queue)143 static inline struct sk_buff *wg_prev_queue_peek(struct prev_queue *queue)
144 {
145 if (queue->peeked)
146 return queue->peeked;
147 queue->peeked = wg_prev_queue_dequeue(queue);
148 return queue->peeked;
149 }
150
151 /* Single consumer */
wg_prev_queue_drop_peeked(struct prev_queue * queue)152 static inline void wg_prev_queue_drop_peeked(struct prev_queue *queue)
153 {
154 queue->peeked = NULL;
155 }
156
wg_queue_enqueue_per_device_and_peer(struct crypt_queue * device_queue,struct prev_queue * peer_queue,struct sk_buff * skb,struct workqueue_struct * wq)157 static inline int wg_queue_enqueue_per_device_and_peer(
158 struct crypt_queue *device_queue, struct prev_queue *peer_queue,
159 struct sk_buff *skb, struct workqueue_struct *wq)
160 {
161 int cpu;
162
163 atomic_set_release(&PACKET_CB(skb)->state, PACKET_STATE_UNCRYPTED);
164 /* We first queue this up for the peer ingestion, but the consumer
165 * will wait for the state to change to CRYPTED or DEAD before.
166 */
167 if (unlikely(!wg_prev_queue_enqueue(peer_queue, skb)))
168 return -ENOSPC;
169
170 /* Then we queue it up in the device queue, which consumes the
171 * packet as soon as it can.
172 */
173 cpu = wg_cpumask_next_online(&device_queue->last_cpu);
174 if (unlikely(ptr_ring_produce_bh(&device_queue->ring, skb)))
175 return -EPIPE;
176 queue_work_on(cpu, wq, &per_cpu_ptr(device_queue->worker, cpu)->work);
177 return 0;
178 }
179
wg_queue_enqueue_per_peer_tx(struct sk_buff * skb,enum packet_state state)180 static inline void wg_queue_enqueue_per_peer_tx(struct sk_buff *skb, enum packet_state state)
181 {
182 /* We take a reference, because as soon as we call atomic_set, the
183 * peer can be freed from below us.
184 */
185 struct wg_peer *peer = wg_peer_get(PACKET_PEER(skb));
186
187 atomic_set_release(&PACKET_CB(skb)->state, state);
188 queue_work_on(wg_cpumask_choose_online(&peer->serial_work_cpu, peer->internal_id),
189 peer->device->packet_crypt_wq, &peer->transmit_packet_work);
190 wg_peer_put(peer);
191 }
192
wg_queue_enqueue_per_peer_rx(struct sk_buff * skb,enum packet_state state)193 static inline void wg_queue_enqueue_per_peer_rx(struct sk_buff *skb, enum packet_state state)
194 {
195 /* We take a reference, because as soon as we call atomic_set, the
196 * peer can be freed from below us.
197 */
198 struct wg_peer *peer = wg_peer_get(PACKET_PEER(skb));
199
200 atomic_set_release(&PACKET_CB(skb)->state, state);
201 napi_schedule(&peer->napi);
202 wg_peer_put(peer);
203 }
204
205 #ifdef DEBUG
206 bool wg_packet_counter_selftest(void);
207 #endif
208
209 #endif /* _WG_QUEUEING_H */
210