| // 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"; |