// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */

#include <vmlinux.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>
#include "bpf_experimental.h"

struct node_data {
        long key;
        long data;
        struct bpf_rb_node node;
};

struct root_nested_inner {
        struct bpf_spin_lock glock;
        struct bpf_rb_root root __contains(node_data, node);
};

struct root_nested {
        struct root_nested_inner inner;
};

long less_callback_ran = -1;
long removed_key = -1;
long first_data[2] = {-1, -1};

#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
private(A) struct bpf_spin_lock glock;
private(A) struct bpf_rb_root groot __contains(node_data, node);
private(A) struct bpf_rb_root groot_array[2] __contains(node_data, node);
private(A) struct bpf_rb_root groot_array_one[1] __contains(node_data, node);
private(B) struct root_nested groot_nested;

static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
        struct node_data *node_a;
        struct node_data *node_b;

        node_a = container_of(a, struct node_data, node);
        node_b = container_of(b, struct node_data, node);
        less_callback_ran = 1;

        return node_a->key < node_b->key;
}

static long __add_three(struct bpf_rb_root *root, struct bpf_spin_lock *lock)
{
        struct node_data *n, *m;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 1;
        n->key = 5;

        m = bpf_obj_new(typeof(*m));
        if (!m) {
                bpf_obj_drop(n);
                return 2;
        }
        m->key = 1;

        bpf_spin_lock(lock);
        bpf_rbtree_add(root, &n->node, less);
        bpf_rbtree_add(root, &m->node, less);
        bpf_spin_unlock(lock);

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 3;
        n->key = 3;

        bpf_spin_lock(lock);
        bpf_rbtree_add(root, &n->node, less);
        bpf_spin_unlock(lock);
        return 0;
}

SEC("tc")
long rbtree_add_nodes(void *ctx)
{
        return __add_three(&groot, &glock);
}

SEC("tc")
long rbtree_add_nodes_nested(void *ctx)
{
        return __add_three(&groot_nested.inner.root, &groot_nested.inner.glock);
}

SEC("tc")
long rbtree_add_and_remove(void *ctx)
{
        struct bpf_rb_node *res = NULL;
        struct node_data *n, *m = NULL;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                goto err_out;
        n->key = 5;

        m = bpf_obj_new(typeof(*m));
        if (!m)
                goto err_out;
        m->key = 3;

        bpf_spin_lock(&glock);
        bpf_rbtree_add(&groot, &n->node, less);
        bpf_rbtree_add(&groot, &m->node, less);
        res = bpf_rbtree_remove(&groot, &n->node);
        bpf_spin_unlock(&glock);

        if (!res)
                return 1;

        n = container_of(res, struct node_data, node);
        removed_key = n->key;
        bpf_obj_drop(n);

        return 0;
err_out:
        if (n)
                bpf_obj_drop(n);
        if (m)
                bpf_obj_drop(m);
        return 1;
}

SEC("tc")
long rbtree_add_and_remove_array(void *ctx)
{
        struct bpf_rb_node *res1 = NULL, *res2 = NULL, *res3 = NULL;
        struct node_data *nodes[3][2] = {{NULL, NULL}, {NULL, NULL}, {NULL, NULL}};
        struct node_data *n;
        long k1 = -1, k2 = -1, k3 = -1;
        int i, j;

        for (i = 0; i < 3; i++) {
                for (j = 0; j < 2; j++) {
                        nodes[i][j] = bpf_obj_new(typeof(*nodes[i][j]));
                        if (!nodes[i][j])
                                goto err_out;
                        nodes[i][j]->key = i * 2 + j;
                }
        }

        bpf_spin_lock(&glock);
        for (i = 0; i < 2; i++)
                for (j = 0; j < 2; j++)
                        bpf_rbtree_add(&groot_array[i], &nodes[i][j]->node, less);
        for (j = 0; j < 2; j++)
                bpf_rbtree_add(&groot_array_one[0], &nodes[2][j]->node, less);
        res1 = bpf_rbtree_remove(&groot_array[0], &nodes[0][0]->node);
        res2 = bpf_rbtree_remove(&groot_array[1], &nodes[1][0]->node);
        res3 = bpf_rbtree_remove(&groot_array_one[0], &nodes[2][0]->node);
        bpf_spin_unlock(&glock);

        if (res1) {
                n = container_of(res1, struct node_data, node);
                k1 = n->key;
                bpf_obj_drop(n);
        }
        if (res2) {
                n = container_of(res2, struct node_data, node);
                k2 = n->key;
                bpf_obj_drop(n);
        }
        if (res3) {
                n = container_of(res3, struct node_data, node);
                k3 = n->key;
                bpf_obj_drop(n);
        }
        if (k1 != 0 || k2 != 2 || k3 != 4)
                return 2;

        return 0;

err_out:
        for (i = 0; i < 3; i++) {
                for (j = 0; j < 2; j++) {
                        if (nodes[i][j])
                                bpf_obj_drop(nodes[i][j]);
                }
        }
        return 1;
}

SEC("tc")
long rbtree_first_and_remove(void *ctx)
{
        struct bpf_rb_node *res = NULL;
        struct node_data *n, *m, *o;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 1;
        n->key = 3;
        n->data = 4;

        m = bpf_obj_new(typeof(*m));
        if (!m)
                goto err_out;
        m->key = 5;
        m->data = 6;

        o = bpf_obj_new(typeof(*o));
        if (!o)
                goto err_out;
        o->key = 1;
        o->data = 2;

        bpf_spin_lock(&glock);
        bpf_rbtree_add(&groot, &n->node, less);
        bpf_rbtree_add(&groot, &m->node, less);
        bpf_rbtree_add(&groot, &o->node, less);

        res = bpf_rbtree_first(&groot);
        if (!res) {
                bpf_spin_unlock(&glock);
                return 2;
        }

        o = container_of(res, struct node_data, node);
        first_data[0] = o->data;

        res = bpf_rbtree_remove(&groot, &o->node);
        bpf_spin_unlock(&glock);

        if (!res)
                return 5;

        o = container_of(res, struct node_data, node);
        removed_key = o->key;
        bpf_obj_drop(o);

        bpf_spin_lock(&glock);
        res = bpf_rbtree_first(&groot);
        if (!res) {
                bpf_spin_unlock(&glock);
                return 3;
        }

        o = container_of(res, struct node_data, node);
        first_data[1] = o->data;
        bpf_spin_unlock(&glock);

        return 0;
err_out:
        if (n)
                bpf_obj_drop(n);
        if (m)
                bpf_obj_drop(m);
        return 1;
}

SEC("tc")
long rbtree_api_release_aliasing(void *ctx)
{
        struct node_data *n, *m, *o;
        struct bpf_rb_node *res, *res2;

        n = bpf_obj_new(typeof(*n));
        if (!n)
                return 1;
        n->key = 41;
        n->data = 42;

        bpf_spin_lock(&glock);
        bpf_rbtree_add(&groot, &n->node, less);
        bpf_spin_unlock(&glock);

        bpf_spin_lock(&glock);

        /* m and o point to the same node,
         * but verifier doesn't know this
         */
        res = bpf_rbtree_first(&groot);
        if (!res)
                goto err_out;
        o = container_of(res, struct node_data, node);

        res = bpf_rbtree_first(&groot);
        if (!res)
                goto err_out;
        m = container_of(res, struct node_data, node);

        res = bpf_rbtree_remove(&groot, &m->node);
        /* Retval of previous remove returns an owning reference to m,
         * which is the same node non-owning ref o is pointing at.
         * We can safely try to remove o as the second rbtree_remove will
         * return NULL since the node isn't in a tree.
         *
         * Previously we relied on the verifier type system + rbtree_remove
         * invalidating non-owning refs to ensure that rbtree_remove couldn't
         * fail, but now rbtree_remove does runtime checking so we no longer
         * invalidate non-owning refs after remove.
         */
        res2 = bpf_rbtree_remove(&groot, &o->node);

        bpf_spin_unlock(&glock);

        if (res) {
                o = container_of(res, struct node_data, node);
                first_data[0] = o->data;
                bpf_obj_drop(o);
        }
        if (res2) {
                /* The second remove fails, so res2 is null and this doesn't
                 * execute
                 */
                m = container_of(res2, struct node_data, node);
                first_data[1] = m->data;
                bpf_obj_drop(m);
        }
        return 0;

err_out:
        bpf_spin_unlock(&glock);
        return 1;
}

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