netcnt_prog.c (1532B)
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 char fmt[] = "%d %llu %llu\n"; 30 union 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 70char _license[] SEC("license") = "GPL";