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/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/*
* AF_XDP user-space access library.
*
* Copyright (c) 2018 - 2019 Intel Corporation.
* Copyright (c) 2019 Facebook
*
* Author(s): Magnus Karlsson <magnus.karlsson@intel.com>
*/
#ifndef __LIBBPF_XSK_H
#define __LIBBPF_XSK_H
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <linux/if_xdp.h>
#include "libbpf.h"
#ifdef __cplusplus
extern "C" {
#endif
/* Load-Acquire Store-Release barriers used by the XDP socket
* library. The following macros should *NOT* be considered part of
* the xsk.h API, and is subject to change anytime.
*
* LIBRARY INTERNAL
*/
#define __XSK_READ_ONCE(x) (*(volatile typeof(x) *)&x)
#define __XSK_WRITE_ONCE(x, v) (*(volatile typeof(x) *)&x) = (v)
#if defined(__i386__) || defined(__x86_64__)
# define libbpf_smp_store_release(p, v) \
do { \
asm volatile("" : : : "memory"); \
__XSK_WRITE_ONCE(*p, v); \
} while (0)
# define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
asm volatile("" : : : "memory"); \
___p1; \
})
#elif defined(__aarch64__)
# define libbpf_smp_store_release(p, v) \
asm volatile ("stlr %w1, %0" : "=Q" (*p) : "r" (v) : "memory")
# define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1; \
asm volatile ("ldar %w0, %1" \
: "=r" (___p1) : "Q" (*p) : "memory"); \
___p1; \
})
#elif defined(__riscv)
# define libbpf_smp_store_release(p, v) \
do { \
asm volatile ("fence rw,w" : : : "memory"); \
__XSK_WRITE_ONCE(*p, v); \
} while (0)
# define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
asm volatile ("fence r,rw" : : : "memory"); \
___p1; \
})
#endif
#ifndef libbpf_smp_store_release
#define libbpf_smp_store_release(p, v) \
do { \
__sync_synchronize(); \
__XSK_WRITE_ONCE(*p, v); \
} while (0)
#endif
#ifndef libbpf_smp_load_acquire
#define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
__sync_synchronize(); \
___p1; \
})
#endif
/* LIBRARY INTERNAL -- END */
/* Do not access these members directly. Use the functions below. */
#define DEFINE_XSK_RING(name) \
struct name { \
__u32 cached_prod; \
__u32 cached_cons; \
__u32 mask; \
__u32 size; \
__u32 *producer; \
__u32 *consumer; \
void *ring; \
__u32 *flags; \
}
DEFINE_XSK_RING(xsk_ring_prod);
DEFINE_XSK_RING(xsk_ring_cons);
/* For a detailed explanation on the memory barriers associated with the
* ring, please take a look at net/xdp/xsk_queue.h.
*/
struct xsk_umem;
struct xsk_socket;
static inline __u64 *xsk_ring_prod__fill_addr(struct xsk_ring_prod *fill,
__u32 idx)
{
__u64 *addrs = (__u64 *)fill->ring;
return &addrs[idx & fill->mask];
}
static inline const __u64 *
xsk_ring_cons__comp_addr(const struct xsk_ring_cons *comp, __u32 idx)
{
const __u64 *addrs = (const __u64 *)comp->ring;
return &addrs[idx & comp->mask];
}
static inline struct xdp_desc *xsk_ring_prod__tx_desc(struct xsk_ring_prod *tx,
__u32 idx)
{
struct xdp_desc *descs = (struct xdp_desc *)tx->ring;
return &descs[idx & tx->mask];
}
static inline const struct xdp_desc *
xsk_ring_cons__rx_desc(const struct xsk_ring_cons *rx, __u32 idx)
{
const struct xdp_desc *descs = (const struct xdp_desc *)rx->ring;
return &descs[idx & rx->mask];
}
static inline int xsk_ring_prod__needs_wakeup(const struct xsk_ring_prod *r)
{
return *r->flags & XDP_RING_NEED_WAKEUP;
}
static inline __u32 xsk_prod_nb_free(struct xsk_ring_prod *r, __u32 nb)
{
__u32 free_entries = r->cached_cons - r->cached_prod;
if (free_entries >= nb)
return free_entries;
/* Refresh the local tail pointer.
* cached_cons is r->size bigger than the real consumer pointer so
* that this addition can be avoided in the more frequently
* executed code that computs free_entries in the beginning of
* this function. Without this optimization it whould have been
* free_entries = r->cached_prod - r->cached_cons + r->size.
*/
r->cached_cons = libbpf_smp_load_acquire(r->consumer);
r->cached_cons += r->size;
return r->cached_cons - r->cached_prod;
}
static inline __u32 xsk_cons_nb_avail(struct xsk_ring_cons *r, __u32 nb)
{
__u32 entries = r->cached_prod - r->cached_cons;
if (entries == 0) {
r->cached_prod = libbpf_smp_load_acquire(r->producer);
entries = r->cached_prod - r->cached_cons;
}
return (entries > nb) ? nb : entries;
}
static inline __u32 xsk_ring_prod__reserve(struct xsk_ring_prod *prod, __u32 nb, __u32 *idx)
{
if (xsk_prod_nb_free(prod, nb) < nb)
return 0;
*idx = prod->cached_prod;
prod->cached_prod += nb;
return nb;
}
static inline void xsk_ring_prod__submit(struct xsk_ring_prod *prod, __u32 nb)
{
/* Make sure everything has been written to the ring before indicating
* this to the kernel by writing the producer pointer.
*/
libbpf_smp_store_release(prod->producer, *prod->producer + nb);
}
static inline __u32 xsk_ring_cons__peek(struct xsk_ring_cons *cons, __u32 nb, __u32 *idx)
{
__u32 entries = xsk_cons_nb_avail(cons, nb);
if (entries > 0) {
*idx = cons->cached_cons;
cons->cached_cons += entries;
}
return entries;
}
static inline void xsk_ring_cons__cancel(struct xsk_ring_cons *cons, __u32 nb)
{
cons->cached_cons -= nb;
}
static inline void xsk_ring_cons__release(struct xsk_ring_cons *cons, __u32 nb)
{
/* Make sure data has been read before indicating we are done
* with the entries by updating the consumer pointer.
*/
libbpf_smp_store_release(cons->consumer, *cons->consumer + nb);
}
static inline void *xsk_umem__get_data(void *umem_area, __u64 addr)
{
return &((char *)umem_area)[addr];
}
static inline __u64 xsk_umem__extract_addr(__u64 addr)
{
return addr & XSK_UNALIGNED_BUF_ADDR_MASK;
}
static inline __u64 xsk_umem__extract_offset(__u64 addr)
{
return addr >> XSK_UNALIGNED_BUF_OFFSET_SHIFT;
}
static inline __u64 xsk_umem__add_offset_to_addr(__u64 addr)
{
return xsk_umem__extract_addr(addr) + xsk_umem__extract_offset(addr);
}
LIBBPF_API int xsk_umem__fd(const struct xsk_umem *umem);
LIBBPF_API int xsk_socket__fd(const struct xsk_socket *xsk);
#define XSK_RING_CONS__DEFAULT_NUM_DESCS 2048
#define XSK_RING_PROD__DEFAULT_NUM_DESCS 2048
#define XSK_UMEM__DEFAULT_FRAME_SHIFT 12 /* 4096 bytes */
#define XSK_UMEM__DEFAULT_FRAME_SIZE (1 << XSK_UMEM__DEFAULT_FRAME_SHIFT)
#define XSK_UMEM__DEFAULT_FRAME_HEADROOM 0
#define XSK_UMEM__DEFAULT_FLAGS 0
struct xsk_umem_config {
__u32 fill_size;
__u32 comp_size;
__u32 frame_size;
__u32 frame_headroom;
__u32 flags;
};
LIBBPF_API int xsk_setup_xdp_prog(int ifindex,
int *xsks_map_fd);
LIBBPF_API int xsk_socket__update_xskmap(struct xsk_socket *xsk,
int xsks_map_fd);
/* Flags for the libbpf_flags field. */
#define XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD (1 << 0)
struct xsk_socket_config {
__u32 rx_size;
__u32 tx_size;
__u32 libbpf_flags;
__u32 xdp_flags;
__u16 bind_flags;
};
/* Set config to NULL to get the default configuration. */
LIBBPF_API int xsk_umem__create(struct xsk_umem **umem,
void *umem_area, __u64 size,
struct xsk_ring_prod *fill,
struct xsk_ring_cons *comp,
const struct xsk_umem_config *config);
LIBBPF_API int xsk_umem__create_v0_0_2(struct xsk_umem **umem,
void *umem_area, __u64 size,
struct xsk_ring_prod *fill,
struct xsk_ring_cons *comp,
const struct xsk_umem_config *config);
LIBBPF_API int xsk_umem__create_v0_0_4(struct xsk_umem **umem,
void *umem_area, __u64 size,
struct xsk_ring_prod *fill,
struct xsk_ring_cons *comp,
const struct xsk_umem_config *config);
LIBBPF_API int xsk_socket__create(struct xsk_socket **xsk,
const char *ifname, __u32 queue_id,
struct xsk_umem *umem,
struct xsk_ring_cons *rx,
struct xsk_ring_prod *tx,
const struct xsk_socket_config *config);
LIBBPF_API int
xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
const char *ifname,
__u32 queue_id, struct xsk_umem *umem,
struct xsk_ring_cons *rx,
struct xsk_ring_prod *tx,
struct xsk_ring_prod *fill,
struct xsk_ring_cons *comp,
const struct xsk_socket_config *config);
/* Returns 0 for success and -EBUSY if the umem is still in use. */
LIBBPF_API int xsk_umem__delete(struct xsk_umem *umem);
LIBBPF_API void xsk_socket__delete(struct xsk_socket *xsk);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* __LIBBPF_XSK_H */
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