sampleip_kern.c (915B)
1/* Copyright 2016 Netflix, Inc. 2 * 3 * This program is free software; you can redistribute it and/or 4 * modify it under the terms of version 2 of the GNU General Public 5 * License as published by the Free Software Foundation. 6 */ 7#include <linux/ptrace.h> 8#include <uapi/linux/bpf.h> 9#include <uapi/linux/bpf_perf_event.h> 10#include <bpf/bpf_helpers.h> 11#include <bpf/bpf_tracing.h> 12 13#define MAX_IPS 8192 14 15struct { 16 __uint(type, BPF_MAP_TYPE_HASH); 17 __type(key, u64); 18 __type(value, u32); 19 __uint(max_entries, MAX_IPS); 20} ip_map SEC(".maps"); 21 22SEC("perf_event") 23int do_sample(struct bpf_perf_event_data *ctx) 24{ 25 u64 ip; 26 u32 *value, init_val = 1; 27 28 ip = PT_REGS_IP(&ctx->regs); 29 value = bpf_map_lookup_elem(&ip_map, &ip); 30 if (value) 31 *value += 1; 32 else 33 /* E2BIG not tested for this example only */ 34 bpf_map_update_elem(&ip_map, &ip, &init_val, BPF_NOEXIST); 35 36 return 0; 37} 38char _license[] SEC("license") = "GPL";