1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
4 * AF_XDP user-space access library.
6 * Copyright (c) 2018 - 2019 Intel Corporation.
7 * Copyright (c) 2019 Facebook
9 * Author(s): Magnus Karlsson <magnus.karlsson@intel.com>
12 #ifndef __LIBBPF_XSK_H
13 #define __LIBBPF_XSK_H
18 #include <linux/if_xdp.h>
26 /* Load-Acquire Store-Release barriers used by the XDP socket
27 * library. The following macros should *NOT* be considered part of
28 * the xsk.h API, and is subject to change anytime.
33 #define __XSK_READ_ONCE(x) (*(volatile typeof(x) *)&x)
34 #define __XSK_WRITE_ONCE(x, v) (*(volatile typeof(x) *)&x) = (v)
36 #if defined(__i386__) || defined(__x86_64__)
37 # define libbpf_smp_store_release(p, v) \
39 asm volatile("" : : : "memory"); \
40 __XSK_WRITE_ONCE(*p, v); \
42 # define libbpf_smp_load_acquire(p) \
44 typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
45 asm volatile("" : : : "memory"); \
48 #elif defined(__aarch64__)
49 # define libbpf_smp_store_release(p, v) \
50 asm volatile ("stlr %w1, %0" : "=Q" (*p) : "r" (v) : "memory")
51 # define libbpf_smp_load_acquire(p) \
54 asm volatile ("ldar %w0, %1" \
55 : "=r" (___p1) : "Q" (*p) : "memory"); \
58 #elif defined(__riscv)
59 # define libbpf_smp_store_release(p, v) \
61 asm volatile ("fence rw,w" : : : "memory"); \
62 __XSK_WRITE_ONCE(*p, v); \
64 # define libbpf_smp_load_acquire(p) \
66 typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
67 asm volatile ("fence r,rw" : : : "memory"); \
72 #ifndef libbpf_smp_store_release
73 #define libbpf_smp_store_release(p, v) \
75 __sync_synchronize(); \
76 __XSK_WRITE_ONCE(*p, v); \
80 #ifndef libbpf_smp_load_acquire
81 #define libbpf_smp_load_acquire(p) \
83 typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
84 __sync_synchronize(); \
89 /* LIBRARY INTERNAL -- END */
91 /* Do not access these members directly. Use the functions below. */
92 #define DEFINE_XSK_RING(name) \
104 DEFINE_XSK_RING(xsk_ring_prod);
105 DEFINE_XSK_RING(xsk_ring_cons);
107 /* For a detailed explanation on the memory barriers associated with the
108 * ring, please take a look at net/xdp/xsk_queue.h.
114 static inline __u64 *xsk_ring_prod__fill_addr(struct xsk_ring_prod *fill,
117 __u64 *addrs = (__u64 *)fill->ring;
119 return &addrs[idx & fill->mask];
122 static inline const __u64 *
123 xsk_ring_cons__comp_addr(const struct xsk_ring_cons *comp, __u32 idx)
125 const __u64 *addrs = (const __u64 *)comp->ring;
127 return &addrs[idx & comp->mask];
130 static inline struct xdp_desc *xsk_ring_prod__tx_desc(struct xsk_ring_prod *tx,
133 struct xdp_desc *descs = (struct xdp_desc *)tx->ring;
135 return &descs[idx & tx->mask];
138 static inline const struct xdp_desc *
139 xsk_ring_cons__rx_desc(const struct xsk_ring_cons *rx, __u32 idx)
141 const struct xdp_desc *descs = (const struct xdp_desc *)rx->ring;
143 return &descs[idx & rx->mask];
146 static inline int xsk_ring_prod__needs_wakeup(const struct xsk_ring_prod *r)
148 return *r->flags & XDP_RING_NEED_WAKEUP;
151 static inline __u32 xsk_prod_nb_free(struct xsk_ring_prod *r, __u32 nb)
153 __u32 free_entries = r->cached_cons - r->cached_prod;
155 if (free_entries >= nb)
158 /* Refresh the local tail pointer.
159 * cached_cons is r->size bigger than the real consumer pointer so
160 * that this addition can be avoided in the more frequently
161 * executed code that computs free_entries in the beginning of
162 * this function. Without this optimization it whould have been
163 * free_entries = r->cached_prod - r->cached_cons + r->size.
165 r->cached_cons = libbpf_smp_load_acquire(r->consumer);
166 r->cached_cons += r->size;
168 return r->cached_cons - r->cached_prod;
171 static inline __u32 xsk_cons_nb_avail(struct xsk_ring_cons *r, __u32 nb)
173 __u32 entries = r->cached_prod - r->cached_cons;
176 r->cached_prod = libbpf_smp_load_acquire(r->producer);
177 entries = r->cached_prod - r->cached_cons;
180 return (entries > nb) ? nb : entries;
183 static inline __u32 xsk_ring_prod__reserve(struct xsk_ring_prod *prod, __u32 nb, __u32 *idx)
185 if (xsk_prod_nb_free(prod, nb) < nb)
188 *idx = prod->cached_prod;
189 prod->cached_prod += nb;
194 static inline void xsk_ring_prod__submit(struct xsk_ring_prod *prod, __u32 nb)
196 /* Make sure everything has been written to the ring before indicating
197 * this to the kernel by writing the producer pointer.
199 libbpf_smp_store_release(prod->producer, *prod->producer + nb);
202 static inline __u32 xsk_ring_cons__peek(struct xsk_ring_cons *cons, __u32 nb, __u32 *idx)
204 __u32 entries = xsk_cons_nb_avail(cons, nb);
207 *idx = cons->cached_cons;
208 cons->cached_cons += entries;
214 static inline void xsk_ring_cons__cancel(struct xsk_ring_cons *cons, __u32 nb)
216 cons->cached_cons -= nb;
219 static inline void xsk_ring_cons__release(struct xsk_ring_cons *cons, __u32 nb)
221 /* Make sure data has been read before indicating we are done
222 * with the entries by updating the consumer pointer.
224 libbpf_smp_store_release(cons->consumer, *cons->consumer + nb);
228 static inline void *xsk_umem__get_data(void *umem_area, __u64 addr)
230 return &((char *)umem_area)[addr];
233 static inline __u64 xsk_umem__extract_addr(__u64 addr)
235 return addr & XSK_UNALIGNED_BUF_ADDR_MASK;
238 static inline __u64 xsk_umem__extract_offset(__u64 addr)
240 return addr >> XSK_UNALIGNED_BUF_OFFSET_SHIFT;
243 static inline __u64 xsk_umem__add_offset_to_addr(__u64 addr)
245 return xsk_umem__extract_addr(addr) + xsk_umem__extract_offset(addr);
248 LIBBPF_API int xsk_umem__fd(const struct xsk_umem *umem);
249 LIBBPF_API int xsk_socket__fd(const struct xsk_socket *xsk);
251 #define XSK_RING_CONS__DEFAULT_NUM_DESCS 2048
252 #define XSK_RING_PROD__DEFAULT_NUM_DESCS 2048
253 #define XSK_UMEM__DEFAULT_FRAME_SHIFT 12 /* 4096 bytes */
254 #define XSK_UMEM__DEFAULT_FRAME_SIZE (1 << XSK_UMEM__DEFAULT_FRAME_SHIFT)
255 #define XSK_UMEM__DEFAULT_FRAME_HEADROOM 0
256 #define XSK_UMEM__DEFAULT_FLAGS 0
258 struct xsk_umem_config {
262 __u32 frame_headroom;
266 LIBBPF_API int xsk_setup_xdp_prog(int ifindex,
268 LIBBPF_API int xsk_socket__update_xskmap(struct xsk_socket *xsk,
271 /* Flags for the libbpf_flags field. */
272 #define XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD (1 << 0)
274 struct xsk_socket_config {
282 /* Set config to NULL to get the default configuration. */
283 LIBBPF_API int xsk_umem__create(struct xsk_umem **umem,
284 void *umem_area, __u64 size,
285 struct xsk_ring_prod *fill,
286 struct xsk_ring_cons *comp,
287 const struct xsk_umem_config *config);
288 LIBBPF_API int xsk_umem__create_v0_0_2(struct xsk_umem **umem,
289 void *umem_area, __u64 size,
290 struct xsk_ring_prod *fill,
291 struct xsk_ring_cons *comp,
292 const struct xsk_umem_config *config);
293 LIBBPF_API int xsk_umem__create_v0_0_4(struct xsk_umem **umem,
294 void *umem_area, __u64 size,
295 struct xsk_ring_prod *fill,
296 struct xsk_ring_cons *comp,
297 const struct xsk_umem_config *config);
298 LIBBPF_API int xsk_socket__create(struct xsk_socket **xsk,
299 const char *ifname, __u32 queue_id,
300 struct xsk_umem *umem,
301 struct xsk_ring_cons *rx,
302 struct xsk_ring_prod *tx,
303 const struct xsk_socket_config *config);
305 xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
307 __u32 queue_id, struct xsk_umem *umem,
308 struct xsk_ring_cons *rx,
309 struct xsk_ring_prod *tx,
310 struct xsk_ring_prod *fill,
311 struct xsk_ring_cons *comp,
312 const struct xsk_socket_config *config);
314 /* Returns 0 for success and -EBUSY if the umem is still in use. */
315 LIBBPF_API int xsk_umem__delete(struct xsk_umem *umem);
316 LIBBPF_API void xsk_socket__delete(struct xsk_socket *xsk);
322 #endif /* __LIBBPF_XSK_H */