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

// 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) { \
		/* below is a dead code with unresolvable CO-RE relo */ \
		i += ((struct __sk_bUfF *)ctx)->len; \
		/* this CO-RE relo may or may not resolve
		 * depending on whether bpf_testmod is loaded.
		 */ \
		i += ((struct bpf_testmod_test_read_ctx *)ctx)->len; \
	} \
	} while (0);
#define C30 C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;
	C30;C30;C30; /* 90 calls */
	return 0;
}

typedef int (*func_proto_typedef___match)(long);
typedef int (*func_proto_typedef___doesnt_match)(char *);
typedef int (*func_proto_typedef_nested1)(func_proto_typedef___match);

int proto_out[3];

SEC("raw_tracepoint/sys_enter")
int core_relo_proto(void *ctx)
{
	proto_out[0] = bpf_core_type_exists(func_proto_typedef___match);
	proto_out[1] = bpf_core_type_exists(func_proto_typedef___doesnt_match);
	proto_out[2] = bpf_core_type_exists(func_proto_typedef_nested1);

	return 0;
}

char LICENSE[] SEC("license") = "GPL";