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 u8 tstamp_type = skb->tstamp_type;
82 skb_scrub_packet(skb, true);
83 memset(&skb->headers, 0, sizeof(skb->headers));
84 if (encapsulating) {
85 skb->l4_hash = l4_hash;
86 skb->sw_hash = sw_hash;
87 skb->hash = hash;
88 skb->tstamp_type = tstamp_type;
89 }
90 skb->queue_mapping = 0;
91 skb->nohdr = 0;
92 skb->peeked = 0;
93 skb->mac_len = 0;
94 skb->dev = NULL;
95 #ifdef CONFIG_NET_SCHED
96 skb->tc_index = 0;
97 #endif
98 skb_reset_redirect(skb);
99 skb->hdr_len = skb_headroom(skb);
100 skb_reset_mac_header(skb);
101 skb_reset_network_header(skb);
102 skb_reset_transport_header(skb);
103 skb_probe_transport_header(skb);
104 skb_reset_inner_headers(skb);
105 }
106
wg_cpumask_choose_online(int * stored_cpu,unsigned int id)107 static inline int wg_cpumask_choose_online(int *stored_cpu, unsigned int id)
108 {
109 unsigned int cpu = *stored_cpu;
110
111 while (unlikely(cpu >= nr_cpu_ids || !cpu_online(cpu)))
112 cpu = *stored_cpu = cpumask_nth(id % num_online_cpus(), cpu_online_mask);
113
114 return cpu;
115 }
116
117 /* This function is racy, in the sense that it's called while last_cpu is
118 * unlocked, so it could return the same CPU twice. Adding locking or using
119 * atomic sequence numbers is slower though, and the consequences of racing are
120 * harmless, so live with it.
121 */
wg_cpumask_next_online(int * last_cpu)122 static inline int wg_cpumask_next_online(int *last_cpu)
123 {
124 int cpu = cpumask_next(READ_ONCE(*last_cpu), cpu_online_mask);
125 if (cpu >= nr_cpu_ids)
126 cpu = cpumask_first(cpu_online_mask);
127 WRITE_ONCE(*last_cpu, cpu);
128 return cpu;
129 }
130
131 void wg_prev_queue_init(struct prev_queue *queue);
132
133 /* Multi producer */
134 bool wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb);
135
136 /* Single consumer */
137 struct sk_buff *wg_prev_queue_dequeue(struct prev_queue *queue);
138
139 /* Single consumer */
wg_prev_queue_peek(struct prev_queue * queue)140 static inline struct sk_buff *wg_prev_queue_peek(struct prev_queue *queue)
141 {
142 if (queue->peeked)
143 return queue->peeked;
144 queue->peeked = wg_prev_queue_dequeue(queue);
145 return queue->peeked;
146 }
147
148 /* Single consumer */
wg_prev_queue_drop_peeked(struct prev_queue * queue)149 static inline void wg_prev_queue_drop_peeked(struct prev_queue *queue)
150 {
151 queue->peeked = NULL;
152 }
153
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)154 static inline int wg_queue_enqueue_per_device_and_peer(
155 struct crypt_queue *device_queue, struct prev_queue *peer_queue,
156 struct sk_buff *skb, struct workqueue_struct *wq)
157 {
158 int cpu;
159
160 atomic_set_release(&PACKET_CB(skb)->state, PACKET_STATE_UNCRYPTED);
161 /* We first queue this up for the peer ingestion, but the consumer
162 * will wait for the state to change to CRYPTED or DEAD before.
163 */
164 if (unlikely(!wg_prev_queue_enqueue(peer_queue, skb)))
165 return -ENOSPC;
166
167 /* Then we queue it up in the device queue, which consumes the
168 * packet as soon as it can.
169 */
170 cpu = wg_cpumask_next_online(&device_queue->last_cpu);
171 if (unlikely(ptr_ring_produce_bh(&device_queue->ring, skb)))
172 return -EPIPE;
173 queue_work_on(cpu, wq, &per_cpu_ptr(device_queue->worker, cpu)->work);
174 return 0;
175 }
176
wg_queue_enqueue_per_peer_tx(struct sk_buff * skb,enum packet_state state)177 static inline void wg_queue_enqueue_per_peer_tx(struct sk_buff *skb, 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 queue_work_on(wg_cpumask_choose_online(&peer->serial_work_cpu, peer->internal_id),
186 peer->device->packet_crypt_wq, &peer->transmit_packet_work);
187 wg_peer_put(peer);
188 }
189
wg_queue_enqueue_per_peer_rx(struct sk_buff * skb,enum packet_state state)190 static inline void wg_queue_enqueue_per_peer_rx(struct sk_buff *skb, enum packet_state state)
191 {
192 /* We take a reference, because as soon as we call atomic_set, the
193 * peer can be freed from below us.
194 */
195 struct wg_peer *peer = wg_peer_get(PACKET_PEER(skb));
196
197 atomic_set_release(&PACKET_CB(skb)->state, state);
198 napi_schedule(&peer->napi);
199 wg_peer_put(peer);
200 }
201
202 #ifdef DEBUG
203 bool wg_packet_counter_selftest(void);
204 #endif
205
206 #endif /* _WG_QUEUEING_H */
207