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 */ 250