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1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2
3/*
4 * AF_XDP user-space access library.
5 *
6 * Copyright (c) 2018 - 2019 Intel Corporation.
7 * Copyright (c) 2019 Facebook
8 *
9 * Author(s): Magnus Karlsson <magnus.karlsson@intel.com>
10 */
11
12#ifndef __XSK_H
13#define __XSK_H
14
15#include <stdio.h>
16#include <stdint.h>
17#include <stdbool.h>
18#include <linux/if_xdp.h>
19
20#include <bpf/libbpf.h>
21
22#ifdef __cplusplus
23extern "C" {
24#endif
25
26/* Do not access these members directly. Use the functions below. */
27#define DEFINE_XSK_RING(name) \
28struct name { \
29 __u32 cached_prod; \
30 __u32 cached_cons; \
31 __u32 mask; \
32 __u32 size; \
33 __u32 *producer; \
34 __u32 *consumer; \
35 void *ring; \
36 __u32 *flags; \
37}
38
39DEFINE_XSK_RING(xsk_ring_prod);
40DEFINE_XSK_RING(xsk_ring_cons);
41
42/* For a detailed explanation on the memory barriers associated with the
43 * ring, please take a look at net/xdp/xsk_queue.h.
44 */
45
46struct xsk_umem;
47struct xsk_socket;
48
49static inline __u64 *xsk_ring_prod__fill_addr(struct xsk_ring_prod *fill,
50 __u32 idx)
51{
52 __u64 *addrs = (__u64 *)fill->ring;
53
54 return &addrs[idx & fill->mask];
55}
56
57static inline const __u64 *
58xsk_ring_cons__comp_addr(const struct xsk_ring_cons *comp, __u32 idx)
59{
60 const __u64 *addrs = (const __u64 *)comp->ring;
61
62 return &addrs[idx & comp->mask];
63}
64
65static inline struct xdp_desc *xsk_ring_prod__tx_desc(struct xsk_ring_prod *tx,
66 __u32 idx)
67{
68 struct xdp_desc *descs = (struct xdp_desc *)tx->ring;
69
70 return &descs[idx & tx->mask];
71}
72
73static inline const struct xdp_desc *
74xsk_ring_cons__rx_desc(const struct xsk_ring_cons *rx, __u32 idx)
75{
76 const struct xdp_desc *descs = (const struct xdp_desc *)rx->ring;
77
78 return &descs[idx & rx->mask];
79}
80
81static inline int xsk_ring_prod__needs_wakeup(const struct xsk_ring_prod *r)
82{
83 return *r->flags & XDP_RING_NEED_WAKEUP;
84}
85
86static inline __u32 xsk_prod_nb_free(struct xsk_ring_prod *r, __u32 nb)
87{
88 __u32 free_entries = r->cached_cons - r->cached_prod;
89
90 if (free_entries >= nb)
91 return free_entries;
92
93 /* Refresh the local tail pointer.
94 * cached_cons is r->size bigger than the real consumer pointer so
95 * that this addition can be avoided in the more frequently
96 * executed code that computs free_entries in the beginning of
97 * this function. Without this optimization it whould have been
98 * free_entries = r->cached_prod - r->cached_cons + r->size.
99 */
100 r->cached_cons = __atomic_load_n(r->consumer, __ATOMIC_ACQUIRE);
101 r->cached_cons += r->size;
102
103 return r->cached_cons - r->cached_prod;
104}
105
106static inline __u32 xsk_cons_nb_avail(struct xsk_ring_cons *r, __u32 nb)
107{
108 __u32 entries = r->cached_prod - r->cached_cons;
109
110 if (entries == 0) {
111 r->cached_prod = __atomic_load_n(r->producer, __ATOMIC_ACQUIRE);
112 entries = r->cached_prod - r->cached_cons;
113 }
114
115 return (entries > nb) ? nb : entries;
116}
117
118static inline __u32 xsk_ring_prod__reserve(struct xsk_ring_prod *prod, __u32 nb, __u32 *idx)
119{
120 if (xsk_prod_nb_free(prod, nb) < nb)
121 return 0;
122
123 *idx = prod->cached_prod;
124 prod->cached_prod += nb;
125
126 return nb;
127}
128
129static inline void xsk_ring_prod__submit(struct xsk_ring_prod *prod, __u32 nb)
130{
131 /* Make sure everything has been written to the ring before indicating
132 * this to the kernel by writing the producer pointer.
133 */
134 __atomic_store_n(prod->producer, *prod->producer + nb, __ATOMIC_RELEASE);
135}
136
137static inline void xsk_ring_prod__cancel(struct xsk_ring_prod *prod, __u32 nb)
138{
139 prod->cached_prod -= nb;
140}
141
142static inline __u32 xsk_ring_cons__peek(struct xsk_ring_cons *cons, __u32 nb, __u32 *idx)
143{
144 __u32 entries = xsk_cons_nb_avail(cons, nb);
145
146 if (entries > 0) {
147 *idx = cons->cached_cons;
148 cons->cached_cons += entries;
149 }
150
151 return entries;
152}
153
154static inline void xsk_ring_cons__cancel(struct xsk_ring_cons *cons, __u32 nb)
155{
156 cons->cached_cons -= nb;
157}
158
159static inline void xsk_ring_cons__release(struct xsk_ring_cons *cons, __u32 nb)
160{
161 /* Make sure data has been read before indicating we are done
162 * with the entries by updating the consumer pointer.
163 */
164 __atomic_store_n(cons->consumer, *cons->consumer + nb, __ATOMIC_RELEASE);
165}
166
167static inline void *xsk_umem__get_data(void *umem_area, __u64 addr)
168{
169 return &((char *)umem_area)[addr];
170}
171
172static inline __u64 xsk_umem__extract_addr(__u64 addr)
173{
174 return addr & XSK_UNALIGNED_BUF_ADDR_MASK;
175}
176
177static inline __u64 xsk_umem__extract_offset(__u64 addr)
178{
179 return addr >> XSK_UNALIGNED_BUF_OFFSET_SHIFT;
180}
181
182static inline __u64 xsk_umem__add_offset_to_addr(__u64 addr)
183{
184 return xsk_umem__extract_addr(addr) + xsk_umem__extract_offset(addr);
185}
186
187int xsk_umem__fd(const struct xsk_umem *umem);
188int xsk_socket__fd(const struct xsk_socket *xsk);
189
190#define XSK_RING_CONS__DEFAULT_NUM_DESCS 2048
191#define XSK_RING_PROD__DEFAULT_NUM_DESCS 2048
192#define XSK_UMEM__DEFAULT_FRAME_SHIFT 12 /* 4096 bytes */
193#define XSK_UMEM__DEFAULT_FRAME_SIZE (1 << XSK_UMEM__DEFAULT_FRAME_SHIFT)
194#define XSK_UMEM__DEFAULT_FRAME_HEADROOM 0
195#define XSK_UMEM__DEFAULT_FLAGS 0
196
197struct xsk_umem_config {
198 __u32 fill_size;
199 __u32 comp_size;
200 __u32 frame_size;
201 __u32 frame_headroom;
202 __u32 flags;
203 __u32 tx_metadata_len;
204};
205
206int xsk_attach_xdp_program(struct bpf_program *prog, int ifindex, u32 xdp_flags);
207void xsk_detach_xdp_program(int ifindex, u32 xdp_flags);
208int xsk_update_xskmap(struct bpf_map *map, struct xsk_socket *xsk, u32 index);
209void xsk_clear_xskmap(struct bpf_map *map);
210bool xsk_is_in_mode(u32 ifindex, int mode);
211
212struct xsk_socket_config {
213 __u32 rx_size;
214 __u32 tx_size;
215 __u16 bind_flags;
216};
217
218/* Set config to NULL to get the default configuration. */
219int xsk_umem__create(struct xsk_umem **umem,
220 void *umem_area, __u64 size,
221 struct xsk_ring_prod *fill,
222 struct xsk_ring_cons *comp,
223 const struct xsk_umem_config *config);
224int xsk_socket__create(struct xsk_socket **xsk,
225 int ifindex, __u32 queue_id,
226 struct xsk_umem *umem,
227 struct xsk_ring_cons *rx,
228 struct xsk_ring_prod *tx,
229 const struct xsk_socket_config *config);
230int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
231 int ifindex,
232 __u32 queue_id, struct xsk_umem *umem,
233 struct xsk_ring_cons *rx,
234 struct xsk_ring_prod *tx,
235 struct xsk_ring_prod *fill,
236 struct xsk_ring_cons *comp,
237 const struct xsk_socket_config *config);
238
239/* Returns 0 for success and -EBUSY if the umem is still in use. */
240int xsk_umem__delete(struct xsk_umem *umem);
241void xsk_socket__delete(struct xsk_socket *xsk);
242
243int xsk_set_mtu(int ifindex, int mtu);
244
245#ifdef __cplusplus
246} /* extern "C" */
247#endif
248
249#endif /* __XSK_H */