tools/testing/selftests/bpf/progs/core_kern.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/progs/core_kern.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/core_kern.c
Extension
.c
Size
3034 bytes
Lines
121
Domain
Support Tooling And Documentation
Bucket
tools
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

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */
#include "vmlinux.h"

#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_core_read.h>

#define ATTR __always_inline
#include "test_jhash.h"

struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__type(key, u32);
	__type(value, u32);
	__uint(max_entries, 256);
} array1 SEC(".maps");

struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__type(key, u32);
	__type(value, u32);
	__uint(max_entries, 256);
} array2 SEC(".maps");

static __noinline int randmap(int v, const struct net_device *dev)
{
	struct bpf_map *map = (struct bpf_map *)&array1;
	int key = bpf_get_prandom_u32() & 0xff;
	int *val;

	if (bpf_get_prandom_u32() & 1)
		map = (struct bpf_map *)&array2;

	val = bpf_map_lookup_elem(map, &key);
	if (val)
		*val = bpf_get_prandom_u32() + v + dev->mtu;

	return 0;
}

SEC("tp_btf/xdp_devmap_xmit")
int BPF_PROG(tp_xdp_devmap_xmit_multi, const struct net_device
	     *from_dev, const struct net_device *to_dev, int sent, int drops,
	     int err)
{
	return randmap(from_dev->ifindex, from_dev);
}

SEC("fentry/eth_type_trans")
int BPF_PROG(fentry_eth_type_trans, struct sk_buff *skb,
	     struct net_device *dev, unsigned short protocol)
{
	return randmap(dev->ifindex + skb->len, dev);
}

SEC("fexit/eth_type_trans")
int BPF_PROG(fexit_eth_type_trans, struct sk_buff *skb,
	     struct net_device *dev, unsigned short protocol)
{
	return randmap(dev->ifindex + skb->len, dev);
}

volatile const int never;

struct __sk_bUfF /* it will not exist in vmlinux */ {
	int len;
} __attribute__((preserve_access_index));

struct bpf_testmod_test_read_ctx /* it exists in bpf_testmod */ {
	size_t len;
} __attribute__((preserve_access_index));

SEC("tc")
int balancer_ingress(struct __sk_buff *ctx)
{
	void *data_end = (void *)(long)ctx->data_end;
	void *data = (void *)(long)ctx->data;
	void *ptr;
	int nh_off, i = 0;

	nh_off = 14;

	/* pragma unroll doesn't work on large loops */
#define C do { \
	ptr = data + i; \
	if (ptr + nh_off > data_end) \
		break; \
	ctx->tc_index = jhash(ptr, nh_off, ctx->cb[0] + i++); \
	if (never) { \

Annotation

Implementation Notes