// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */

#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"

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

struct bpf_map;

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __type(key, __u32);
        __type(value, __u32);
        __uint(max_entries, 1000);
} map_random_data SEC(".maps");

struct map_bloom_type {
        __uint(type, BPF_MAP_TYPE_BLOOM_FILTER);
        __type(value, __u32);
        __uint(max_entries, 10000);
        __uint(map_extra, 5);
} map_bloom SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
        __type(key, int);
        __type(value, int);
        __uint(max_entries, 1);
        __array(values, struct map_bloom_type);
} outer_map SEC(".maps");

struct callback_ctx {
        struct bpf_map *map;
};

int error = 0;

static __u64
check_elem(struct bpf_map *map, __u32 *key, __u32 *val,
           struct callback_ctx *data)
{
        int err;

        err = bpf_map_peek_elem(data->map, val);
        if (err) {
                error |= 1;
                return 1; /* stop the iteration */
        }

        return 0;
}

SEC("fentry/" SYS_PREFIX "sys_getpgid")
int inner_map(void *ctx)
{
        struct bpf_map *inner_map;
        struct callback_ctx data;
        int key = 0;

        inner_map = bpf_map_lookup_elem(&outer_map, &key);
        if (!inner_map) {
                error |= 2;
                return 0;
        }

        data.map = inner_map;
        bpf_for_each_map_elem(&map_random_data, check_elem, &data, 0);

        return 0;
}

SEC("fentry/" SYS_PREFIX "sys_getpgid")
int check_bloom(void *ctx)
{
        struct callback_ctx data;

        data.map = (struct bpf_map *)&map_bloom;
        bpf_for_each_map_elem(&map_random_data, check_elem, &data, 0);

        return 0;
}