LXR linux/samples/bpf/xdpsock

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/bpf.h>
   3#include <bpf/bpf_helpers.h>
   4#include "xdpsock.h"
   5
   6/* This XDP program is only needed for the XDP_SHARED_UMEM mode.
   7 * If you do not use this mode, libbpf can supply an XDP program for you.
   8 */
   9
  10struct {
  11        __uint(type, BPF_MAP_TYPE_XSKMAP);
  12        __uint(max_entries, MAX_SOCKS);
  13        __uint(key_size, sizeof(int));
  14        __uint(value_size, sizeof(int));
  15} xsks_map SEC(".maps");
  16
  17static unsigned int rr;
  18
  19SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx)
  20{
  21        rr = (rr + 1) & (MAX_SOCKS - 1);
  22
  23        return bpf_redirect_map(&xsks_map, rr, XDP_DROP);
  24}
  25