LXR linux/samples/bpf/sampleip

   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";
  39