samples/bpf/xdpsock_kern.c

   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
  10 struct {
  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
  17 static unsigned int rr;
  18
  19 SEC("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 }