1// SPDX-License-Identifier: GPL-2.0
2#include <linux/bpf.h>
3#include <linux/version.h>
4
5#include <bpf/bpf_helpers.h>
6#include "netcnt_common.h"
7
8#define MAX_BPS	(3 * 1024 * 1024)
9
10#define REFRESH_TIME_NS	100000000
11#define NS_PER_SEC	1000000000
12
13struct {
14	__uint(type, BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
15	__type(key, struct bpf_cgroup_storage_key);
16	__type(value, union percpu_net_cnt);
17} percpu_netcnt SEC(".maps");
18
19struct {
20	__uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
21	__type(key, struct bpf_cgroup_storage_key);
22	__type(value, union net_cnt);
23} netcnt SEC(".maps");
24
25SEC("cgroup/skb")
26int bpf_nextcnt(struct __sk_buff *skb)
27{
28	union percpu_net_cnt *percpu_cnt;
29	union net_cnt *cnt;
30	__u64 ts, dt;
31	int ret;
32
33	cnt = bpf_get_local_storage(&netcnt, 0);
34	percpu_cnt = bpf_get_local_storage(&percpu_netcnt, 0);
35
36	percpu_cnt->packets++;
37	percpu_cnt->bytes += skb->len;
38
39	if (percpu_cnt->packets > MAX_PERCPU_PACKETS) {
40		__sync_fetch_and_add(&cnt->packets,
41				     percpu_cnt->packets);
42		percpu_cnt->packets = 0;
43
44		__sync_fetch_and_add(&cnt->bytes,
45				     percpu_cnt->bytes);
46		percpu_cnt->bytes = 0;
47	}
48
49	ts = bpf_ktime_get_ns();
50	dt = ts - percpu_cnt->prev_ts;
51
52	dt *= MAX_BPS;
53	dt /= NS_PER_SEC;
54
55	if (cnt->bytes + percpu_cnt->bytes - percpu_cnt->prev_bytes < dt)
56		ret = 1;
57	else
58		ret = 0;
59
60	if (dt > REFRESH_TIME_NS) {
61		percpu_cnt->prev_ts = ts;
62		percpu_cnt->prev_packets = cnt->packets;
63		percpu_cnt->prev_bytes = cnt->bytes;
64	}
65
66	return !!ret;
67}
68
69char _license[] SEC("license") = "GPL";
70