linux/samples/bpf/sampleip_kern.c

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/* Copyright 2016 Netflix, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include <linux/version.h>
#include <linux/ptrace.h>
#include <uapi/linux/bpf.h>
#include <uapi/linux/bpf_perf_event.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#define MAX_IPS 8192
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, u64);
__type(value, u32);
__uint(max_entries, MAX_IPS);
} ip_map SEC(".maps");
SEC("perf_event")
int do_sample(struct bpf_perf_event_data *ctx)
{
u64 ip;
u32 *value, init_val = 1;
ip = PT_REGS_IP(&ctx->regs);
value = bpf_map_lookup_elem(&ip_map, &ip);
if (value)
*value += 1;
else
/* E2BIG not tested for this example only */
bpf_map_update_elem(&ip_map, &ip, &init_val, BPF_NOEXIST);
return 0;
}
char _license[] SEC("license") = "GPL";