tools/testing/selftests/bpf/progs/cgroup_storage.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/bpf.h>
   4 #include <bpf/bpf_helpers.h>
   5
   6 struct {
   7         __uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
   8         __type(key, struct bpf_cgroup_storage_key);
   9         __type(value, __u64);
  10 } cgroup_storage SEC(".maps");
  11
  12 SEC("cgroup_skb/egress")
  13 int bpf_prog(struct __sk_buff *skb)
  14 {
  15         __u64 *counter;
  16
  17         counter = bpf_get_local_storage(&cgroup_storage, 0);
  18         __sync_fetch_and_add(counter, 1);
  19
  20         /* Drop one out of every two packets */
  21         return (*counter & 1);
  22 }
  23
  24 char _license[] SEC("license") = "GPL";