25 lines
522 B
C
25 lines
522 B
C
// SPDX-License-Identifier: GPL-2.0
|
|
|
|
#include <linux/bpf.h>
|
|
#include <bpf/bpf_helpers.h>
|
|
|
|
struct {
|
|
__uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
|
|
__type(key, struct bpf_cgroup_storage_key);
|
|
__type(value, __u64);
|
|
} cgroup_storage SEC(".maps");
|
|
|
|
SEC("cgroup_skb/egress")
|
|
int bpf_prog(struct __sk_buff *skb)
|
|
{
|
|
__u64 *counter;
|
|
|
|
counter = bpf_get_local_storage(&cgroup_storage, 0);
|
|
__sync_fetch_and_add(counter, 1);
|
|
|
|
/* Drop one out of every two packets */
|
|
return (*counter & 1);
|
|
}
|
|
|
|
char _license[] SEC("license") = "GPL";
|