samples/bpf/sampleip_kern.c

Source file repositories/reference/linux-study-clean/samples/bpf/sampleip_kern.c

File Facts

System
Linux kernel
Corpus path
samples/bpf/sampleip_kern.c
Extension
.c
Size
915 bytes
Lines
39
Domain
Support Tooling And Documentation
Bucket
samples
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

#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";

Annotation

Implementation Notes