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.
8 * Author(s): Magnus Karlsson <magnus.karlsson@intel.com>
11 #ifndef __LIBBPF_XSK_H
12 #define __LIBBPF_XSK_H
16 #include <linux/if_xdp.h>
19 #include "libbpf_util.h"
25 /* Do not access these members directly. Use the functions below. */
26 #define DEFINE_XSK_RING(name) \
38 DEFINE_XSK_RING(xsk_ring_prod);
39 DEFINE_XSK_RING(xsk_ring_cons);
41 /* For a detailed explanation on the memory barriers associated with the
42 * ring, please take a look at net/xdp/xsk_queue.h.
48 static inline __u64 *xsk_ring_prod__fill_addr(struct xsk_ring_prod *fill,
51 __u64 *addrs = (__u64 *)fill->ring;
53 return &addrs[idx & fill->mask];
56 static inline const __u64 *
57 xsk_ring_cons__comp_addr(const struct xsk_ring_cons *comp, __u32 idx)
59 const __u64 *addrs = (const __u64 *)comp->ring;
61 return &addrs[idx & comp->mask];
64 static inline struct xdp_desc *xsk_ring_prod__tx_desc(struct xsk_ring_prod *tx,
67 struct xdp_desc *descs = (struct xdp_desc *)tx->ring;
69 return &descs[idx & tx->mask];
72 static inline const struct xdp_desc *
73 xsk_ring_cons__rx_desc(const struct xsk_ring_cons *rx, __u32 idx)
75 const struct xdp_desc *descs = (const struct xdp_desc *)rx->ring;
77 return &descs[idx & rx->mask];
80 static inline int xsk_ring_prod__needs_wakeup(const struct xsk_ring_prod *r)
82 return *r->flags & XDP_RING_NEED_WAKEUP;
85 static inline __u32 xsk_prod_nb_free(struct xsk_ring_prod *r, __u32 nb)
87 __u32 free_entries = r->cached_cons - r->cached_prod;
89 if (free_entries >= nb)
92 /* Refresh the local tail pointer.
93 * cached_cons is r->size bigger than the real consumer pointer so
94 * that this addition can be avoided in the more frequently
95 * executed code that computs free_entries in the beginning of
96 * this function. Without this optimization it whould have been
97 * free_entries = r->cached_prod - r->cached_cons + r->size.
99 r->cached_cons = *r->consumer + r->size;
101 return r->cached_cons - r->cached_prod;
104 static inline __u32 xsk_cons_nb_avail(struct xsk_ring_cons *r, __u32 nb)
106 __u32 entries = r->cached_prod - r->cached_cons;
109 r->cached_prod = *r->producer;
110 entries = r->cached_prod - r->cached_cons;
113 return (entries > nb) ? nb : entries;
116 static inline size_t xsk_ring_prod__reserve(struct xsk_ring_prod *prod,
117 size_t nb, __u32 *idx)
119 if (xsk_prod_nb_free(prod, nb) < nb)
122 *idx = prod->cached_prod;
123 prod->cached_prod += nb;
128 static inline void xsk_ring_prod__submit(struct xsk_ring_prod *prod, size_t nb)
130 /* Make sure everything has been written to the ring before indicating
131 * this to the kernel by writing the producer pointer.
135 *prod->producer += nb;
138 static inline size_t xsk_ring_cons__peek(struct xsk_ring_cons *cons,
139 size_t nb, __u32 *idx)
141 size_t entries = xsk_cons_nb_avail(cons, nb);
144 /* Make sure we do not speculatively read the data before
145 * we have received the packet buffers from the ring.
149 *idx = cons->cached_cons;
150 cons->cached_cons += entries;
156 static inline void xsk_ring_cons__release(struct xsk_ring_cons *cons, size_t nb)
158 /* Make sure data has been read before indicating we are done
159 * with the entries by updating the consumer pointer.
163 *cons->consumer += nb;
166 static inline void *xsk_umem__get_data(void *umem_area, __u64 addr)
168 return &((char *)umem_area)[addr];
171 static inline __u64 xsk_umem__extract_addr(__u64 addr)
173 return addr & XSK_UNALIGNED_BUF_ADDR_MASK;
176 static inline __u64 xsk_umem__extract_offset(__u64 addr)
178 return addr >> XSK_UNALIGNED_BUF_OFFSET_SHIFT;
181 static inline __u64 xsk_umem__add_offset_to_addr(__u64 addr)
183 return xsk_umem__extract_addr(addr) + xsk_umem__extract_offset(addr);
186 LIBBPF_API int xsk_umem__fd(const struct xsk_umem *umem);
187 LIBBPF_API int xsk_socket__fd(const struct xsk_socket *xsk);
189 #define XSK_RING_CONS__DEFAULT_NUM_DESCS 2048
190 #define XSK_RING_PROD__DEFAULT_NUM_DESCS 2048
191 #define XSK_UMEM__DEFAULT_FRAME_SHIFT 12 /* 4096 bytes */
192 #define XSK_UMEM__DEFAULT_FRAME_SIZE (1 << XSK_UMEM__DEFAULT_FRAME_SHIFT)
193 #define XSK_UMEM__DEFAULT_FRAME_HEADROOM 0
194 #define XSK_UMEM__DEFAULT_FLAGS 0
196 struct xsk_umem_config {
200 __u32 frame_headroom;
204 /* Flags for the libbpf_flags field. */
205 #define XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD (1 << 0)
207 struct xsk_socket_config {
215 /* Set config to NULL to get the default configuration. */
216 LIBBPF_API int xsk_umem__create(struct xsk_umem **umem,
217 void *umem_area, __u64 size,
218 struct xsk_ring_prod *fill,
219 struct xsk_ring_cons *comp,
220 const struct xsk_umem_config *config);
221 LIBBPF_API int xsk_umem__create_v0_0_2(struct xsk_umem **umem,
222 void *umem_area, __u64 size,
223 struct xsk_ring_prod *fill,
224 struct xsk_ring_cons *comp,
225 const struct xsk_umem_config *config);
226 LIBBPF_API int xsk_umem__create_v0_0_4(struct xsk_umem **umem,
227 void *umem_area, __u64 size,
228 struct xsk_ring_prod *fill,
229 struct xsk_ring_cons *comp,
230 const struct xsk_umem_config *config);
231 LIBBPF_API int xsk_socket__create(struct xsk_socket **xsk,
232 const char *ifname, __u32 queue_id,
233 struct xsk_umem *umem,
234 struct xsk_ring_cons *rx,
235 struct xsk_ring_prod *tx,
236 const struct xsk_socket_config *config);
238 /* Returns 0 for success and -EBUSY if the umem is still in use. */
239 LIBBPF_API int xsk_umem__delete(struct xsk_umem *umem);
240 LIBBPF_API void xsk_socket__delete(struct xsk_socket *xsk);
246 #endif /* __LIBBPF_XSK_H */