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
13 struct {
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
19 struct {
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
25 SEC("cgroup/skb")
bpf_nextcnt(struct __sk_buff * skb)26 int 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
69 char _license[] SEC("license") = "GPL";
70
