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/version.h>
 8#include <linux/ptrace.h>
 9#include <uapi/linux/bpf.h>
10#include <uapi/linux/bpf_perf_event.h>
11#include <bpf/bpf_helpers.h>
12#include <bpf/bpf_tracing.h>
13
14#define MAX_IPS		8192
15
16struct {
17	__uint(type, BPF_MAP_TYPE_HASH);
18	__type(key, u64);
19	__type(value, u32);
20	__uint(max_entries, MAX_IPS);
21} ip_map SEC(".maps");
22
23SEC("perf_event")
24int do_sample(struct bpf_perf_event_data *ctx)
25{
26	u64 ip;
27	u32 *value, init_val = 1;
28
29	ip = PT_REGS_IP(&ctx->regs);
30	value = bpf_map_lookup_elem(&ip_map, &ip);
31	if (value)
32		*value += 1;
33	else
34		/* E2BIG not tested for this example only */
35		bpf_map_update_elem(&ip_map, &ip, &init_val, BPF_NOEXIST);
36
37	return 0;
38}
39char _license[] SEC("license") = "GPL";