1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/bpf.h>
3 #include <linux/version.h>
4 
5 #include "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, struct 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, struct net_cnt);
23 } netcnt SEC(".maps");
24 
25 SEC("cgroup/skb")
26 int bpf_nextcnt(struct __sk_buff *skb)
27 {
28 	struct percpu_net_cnt *percpu_cnt;
29 	char fmt[] = "%d %llu %llu\n";
30 	struct net_cnt *cnt;
31 	__u64 ts, dt;
32 	int ret;
33 
34 	cnt = bpf_get_local_storage(&netcnt, 0);
35 	percpu_cnt = bpf_get_local_storage(&percpu_netcnt, 0);
36 
37 	percpu_cnt->packets++;
38 	percpu_cnt->bytes += skb->len;
39 
40 	if (percpu_cnt->packets > MAX_PERCPU_PACKETS) {
41 		__sync_fetch_and_add(&cnt->packets,
42 				     percpu_cnt->packets);
43 		percpu_cnt->packets = 0;
44 
45 		__sync_fetch_and_add(&cnt->bytes,
46 				     percpu_cnt->bytes);
47 		percpu_cnt->bytes = 0;
48 	}
49 
50 	ts = bpf_ktime_get_ns();
51 	dt = ts - percpu_cnt->prev_ts;
52 
53 	dt *= MAX_BPS;
54 	dt /= NS_PER_SEC;
55 
56 	if (cnt->bytes + percpu_cnt->bytes - percpu_cnt->prev_bytes < dt)
57 		ret = 1;
58 	else
59 		ret = 0;
60 
61 	if (dt > REFRESH_TIME_NS) {
62 		percpu_cnt->prev_ts = ts;
63 		percpu_cnt->prev_packets = cnt->packets;
64 		percpu_cnt->prev_bytes = cnt->bytes;
65 	}
66 
67 	return !!ret;
68 }
69 
70 char _license[] SEC("license") = "GPL";
71 __u32 _version SEC("version") = LINUX_VERSION_CODE;
72