// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Facebook
#include <linux/bpf.h>
#include <linux/version.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"

struct hmap_elem {
        volatile int cnt;
        struct bpf_spin_lock lock;
        int test_padding;
};

struct {
        __uint(type, BPF_MAP_TYPE_HASH);
        __uint(max_entries, 1);
        __type(key, int);
        __type(value, struct hmap_elem);
} hmap SEC(".maps");

struct cls_elem {
        struct bpf_spin_lock lock;
        volatile int cnt;
};

struct {
        __uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
        __type(key, struct bpf_cgroup_storage_key);
        __type(value, struct cls_elem);
} cls_map SEC(".maps");

struct bpf_vqueue {
        struct bpf_spin_lock lock;
        /* 4 byte hole */
        unsigned long long lasttime;
        int credit;
        unsigned int rate;
};

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 1);
        __type(key, int);
        __type(value, struct bpf_vqueue);
} vqueue SEC(".maps");

#define CREDIT_PER_NS(delta, rate) (((delta) * rate) >> 20)

SEC("cgroup_skb/ingress")
int bpf_spin_lock_test(struct __sk_buff *skb)
{
        volatile int credit = 0, max_credit = 100, pkt_len = 64;
        struct hmap_elem zero = {}, *val;
        unsigned long long curtime;
        struct bpf_vqueue *q;
        struct cls_elem *cls;
        int key = 0;
        int err = 0;

        val = bpf_map_lookup_elem(&hmap, &key);
        if (!val) {
                bpf_map_update_elem(&hmap, &key, &zero, 0);
                val = bpf_map_lookup_elem(&hmap, &key);
                if (!val) {
                        err = 1;
                        goto err;
                }
        }
        /* spin_lock in hash map run time test */
        bpf_spin_lock(&val->lock);
        if (val->cnt)
                val->cnt--;
        else
                val->cnt++;
        if (val->cnt != 0 && val->cnt != 1)
                err = 1;
        bpf_spin_unlock(&val->lock);

        /* spin_lock in array. virtual queue demo */
        q = bpf_map_lookup_elem(&vqueue, &key);
        if (!q)
                goto err;
        curtime = bpf_ktime_get_ns();
        bpf_spin_lock(&q->lock);
        q->credit += CREDIT_PER_NS(curtime - q->lasttime, q->rate);
        q->lasttime = curtime;
        if (q->credit > max_credit)
                q->credit = max_credit;
        q->credit -= pkt_len;
        credit = q->credit;
        bpf_spin_unlock(&q->lock);

        __sink(credit);

        /* spin_lock in cgroup local storage */
        cls = bpf_get_local_storage(&cls_map, 0);
        bpf_spin_lock(&cls->lock);
        cls->cnt++;
        bpf_spin_unlock(&cls->lock);

err:
        return err;
}

struct bpf_spin_lock lockA __hidden SEC(".data.A");

__noinline
static int static_subprog(struct __sk_buff *ctx)
{
        volatile int ret = 0;

        if (ctx->protocol)
                return ret;
        return ret + ctx->len;
}

__noinline
static int static_subprog_lock(struct __sk_buff *ctx)
{
        volatile int ret = 0;

        ret = static_subprog(ctx);
        bpf_spin_lock(&lockA);
        return ret + ctx->len;
}

__noinline
static int static_subprog_unlock(struct __sk_buff *ctx)
{
        volatile int ret = 0;

        ret = static_subprog(ctx);
        bpf_spin_unlock(&lockA);
        return ret + ctx->len;
}

SEC("tc")
int lock_static_subprog_call(struct __sk_buff *ctx)
{
        int ret = 0;

        bpf_spin_lock(&lockA);
        if (ctx->mark == 42)
                ret = static_subprog(ctx);
        bpf_spin_unlock(&lockA);
        return ret;
}

SEC("tc")
int lock_static_subprog_lock(struct __sk_buff *ctx)
{
        int ret = 0;

        ret = static_subprog_lock(ctx);
        bpf_spin_unlock(&lockA);
        return ret;
}

SEC("tc")
int lock_static_subprog_unlock(struct __sk_buff *ctx)
{
        int ret = 0;

        bpf_spin_lock(&lockA);
        ret = static_subprog_unlock(ctx);
        return ret;
}

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