sampleip_kern.c 942 B

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  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. #define MAX_IPS 8192
  14. struct {
  15. __uint(type, BPF_MAP_TYPE_HASH);
  16. __type(key, u64);
  17. __type(value, u32);
  18. __uint(max_entries, MAX_IPS);
  19. } ip_map SEC(".maps");
  20. SEC("perf_event")
  21. int do_sample(struct bpf_perf_event_data *ctx)
  22. {
  23. u64 ip;
  24. u32 *value, init_val = 1;
  25. ip = PT_REGS_IP(&ctx->regs);
  26. value = bpf_map_lookup_elem(&ip_map, &ip);
  27. if (value)
  28. *value += 1;
  29. else
  30. /* E2BIG not tested for this example only */
  31. bpf_map_update_elem(&ip_map, &ip, &init_val, BPF_NOEXIST);
  32. return 0;
  33. }
  34. char _license[] SEC("license") = "GPL";