//SPDX-License-Identifier: GPL-2.0
  #include <linux/bpf-cgroup.h>
  #include <linux/bpf.h>

  #include <linux/btf.h>

  #include <linux/bug.h>
  #include <linux/filter.h>
  #include <linux/mm.h>
  #include <linux/rbtree.h>
  #include <linux/slab.h>

  #include <uapi/linux/btf.h>

  DEFINE_PER_CPU(struct bpf_cgroup_storage*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);

  #ifdef CONFIG_CGROUP_BPF
  
  #define LOCAL_STORAGE_CREATE_FLAG_MASK					\

  	(BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK)

  
  struct bpf_cgroup_storage_map {
  	struct bpf_map map;
  
  	spinlock_t lock;
  	struct bpf_prog *prog;
  	struct rb_root root;
  	struct list_head list;
  };
  
  static struct bpf_cgroup_storage_map *map_to_storage(struct bpf_map *map)
  {
  	return container_of(map, struct bpf_cgroup_storage_map, map);
  }
  
  static int bpf_cgroup_storage_key_cmp(
  	const struct bpf_cgroup_storage_key *key1,
  	const struct bpf_cgroup_storage_key *key2)
  {
  	if (key1->cgroup_inode_id < key2->cgroup_inode_id)
  		return -1;
  	else if (key1->cgroup_inode_id > key2->cgroup_inode_id)
  		return 1;
  	else if (key1->attach_type < key2->attach_type)
  		return -1;
  	else if (key1->attach_type > key2->attach_type)
  		return 1;
  	return 0;
  }
  
  static struct bpf_cgroup_storage *cgroup_storage_lookup(
  	struct bpf_cgroup_storage_map *map, struct bpf_cgroup_storage_key *key,
  	bool locked)
  {
  	struct rb_root *root = &map->root;
  	struct rb_node *node;
  
  	if (!locked)
  		spin_lock_bh(&map->lock);
  
  	node = root->rb_node;
  	while (node) {
  		struct bpf_cgroup_storage *storage;
  
  		storage = container_of(node, struct bpf_cgroup_storage, node);
  
  		switch (bpf_cgroup_storage_key_cmp(key, &storage->key)) {
  		case -1:
  			node = node->rb_left;
  			break;
  		case 1:
  			node = node->rb_right;
  			break;
  		default:
  			if (!locked)
  				spin_unlock_bh(&map->lock);
  			return storage;
  		}
  	}
  
  	if (!locked)
  		spin_unlock_bh(&map->lock);
  
  	return NULL;
  }
  
  static int cgroup_storage_insert(struct bpf_cgroup_storage_map *map,
  				 struct bpf_cgroup_storage *storage)
  {
  	struct rb_root *root = &map->root;
  	struct rb_node **new = &(root->rb_node), *parent = NULL;
  
  	while (*new) {
  		struct bpf_cgroup_storage *this;
  
  		this = container_of(*new, struct bpf_cgroup_storage, node);
  
  		parent = *new;
  		switch (bpf_cgroup_storage_key_cmp(&storage->key, &this->key)) {
  		case -1:
  			new = &((*new)->rb_left);
  			break;
  		case 1:
  			new = &((*new)->rb_right);
  			break;
  		default:
  			return -EEXIST;
  		}
  	}
  
  	rb_link_node(&storage->node, parent, new);
  	rb_insert_color(&storage->node, root);
  
  	return 0;
  }
  
  static void *cgroup_storage_lookup_elem(struct bpf_map *_map, void *_key)
  {
  	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
  	struct bpf_cgroup_storage_key *key = _key;
  	struct bpf_cgroup_storage *storage;
  
  	storage = cgroup_storage_lookup(map, key, false);
  	if (!storage)
  		return NULL;
  
  	return &READ_ONCE(storage->buf)->data[0];
  }
  
  static int cgroup_storage_update_elem(struct bpf_map *map, void *_key,
  				      void *value, u64 flags)
  {
  	struct bpf_cgroup_storage_key *key = _key;
  	struct bpf_cgroup_storage *storage;
  	struct bpf_storage_buffer *new;

  	if (unlikely(flags & ~(BPF_F_LOCK | BPF_EXIST | BPF_NOEXIST)))
  		return -EINVAL;
  
  	if (unlikely(flags & BPF_NOEXIST))
  		return -EINVAL;
  
  	if (unlikely((flags & BPF_F_LOCK) &&
  		     !map_value_has_spin_lock(map)))

  		return -EINVAL;
  
  	storage = cgroup_storage_lookup((struct bpf_cgroup_storage_map *)map,
  					key, false);
  	if (!storage)
  		return -ENOENT;

  	if (flags & BPF_F_LOCK) {
  		copy_map_value_locked(map, storage->buf->data, value, false);
  		return 0;
  	}

  	new = kmalloc_node(sizeof(struct bpf_storage_buffer) +

  			   map->value_size,
  			   __GFP_ZERO | GFP_ATOMIC | __GFP_NOWARN,

  			   map->numa_node);
  	if (!new)
  		return -ENOMEM;
  
  	memcpy(&new->data[0], value, map->value_size);

  	check_and_init_map_lock(map, new->data);

  
  	new = xchg(&storage->buf, new);
  	kfree_rcu(new, rcu);
  
  	return 0;
  }

  int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *_key,
  				   void *value)
  {
  	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
  	struct bpf_cgroup_storage_key *key = _key;
  	struct bpf_cgroup_storage *storage;
  	int cpu, off = 0;
  	u32 size;
  
  	rcu_read_lock();
  	storage = cgroup_storage_lookup(map, key, false);
  	if (!storage) {
  		rcu_read_unlock();
  		return -ENOENT;
  	}
  
  	/* per_cpu areas are zero-filled and bpf programs can only
  	 * access 'value_size' of them, so copying rounded areas
  	 * will not leak any kernel data
  	 */
  	size = round_up(_map->value_size, 8);
  	for_each_possible_cpu(cpu) {
  		bpf_long_memcpy(value + off,
  				per_cpu_ptr(storage->percpu_buf, cpu), size);
  		off += size;
  	}
  	rcu_read_unlock();
  	return 0;
  }
  
  int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *_key,
  				     void *value, u64 map_flags)
  {
  	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
  	struct bpf_cgroup_storage_key *key = _key;
  	struct bpf_cgroup_storage *storage;
  	int cpu, off = 0;
  	u32 size;
  
  	if (map_flags != BPF_ANY && map_flags != BPF_EXIST)
  		return -EINVAL;
  
  	rcu_read_lock();
  	storage = cgroup_storage_lookup(map, key, false);
  	if (!storage) {
  		rcu_read_unlock();
  		return -ENOENT;
  	}
  
  	/* the user space will provide round_up(value_size, 8) bytes that
  	 * will be copied into per-cpu area. bpf programs can only access
  	 * value_size of it. During lookup the same extra bytes will be
  	 * returned or zeros which were zero-filled by percpu_alloc,
  	 * so no kernel data leaks possible
  	 */
  	size = round_up(_map->value_size, 8);
  	for_each_possible_cpu(cpu) {
  		bpf_long_memcpy(per_cpu_ptr(storage->percpu_buf, cpu),
  				value + off, size);
  		off += size;
  	}
  	rcu_read_unlock();
  	return 0;
  }

  static int cgroup_storage_get_next_key(struct bpf_map *_map, void *_key,
  				       void *_next_key)
  {
  	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
  	struct bpf_cgroup_storage_key *key = _key;
  	struct bpf_cgroup_storage_key *next = _next_key;
  	struct bpf_cgroup_storage *storage;
  
  	spin_lock_bh(&map->lock);
  
  	if (list_empty(&map->list))
  		goto enoent;
  
  	if (key) {
  		storage = cgroup_storage_lookup(map, key, true);
  		if (!storage)
  			goto enoent;
  
  		storage = list_next_entry(storage, list);
  		if (!storage)
  			goto enoent;
  	} else {
  		storage = list_first_entry(&map->list,
  					 struct bpf_cgroup_storage, list);
  	}
  
  	spin_unlock_bh(&map->lock);
  	next->attach_type = storage->key.attach_type;
  	next->cgroup_inode_id = storage->key.cgroup_inode_id;
  	return 0;
  
  enoent:
  	spin_unlock_bh(&map->lock);
  	return -ENOENT;
  }
  
  static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr)
  {
  	int numa_node = bpf_map_attr_numa_node(attr);
  	struct bpf_cgroup_storage_map *map;

  	struct bpf_map_memory mem;

  	int ret;

  
  	if (attr->key_size != sizeof(struct bpf_cgroup_storage_key))
  		return ERR_PTR(-EINVAL);

  	if (attr->value_size == 0)
  		return ERR_PTR(-EINVAL);

  	if (attr->value_size > PAGE_SIZE)
  		return ERR_PTR(-E2BIG);

  	if (attr->map_flags & ~LOCAL_STORAGE_CREATE_FLAG_MASK ||
  	    !bpf_map_flags_access_ok(attr->map_flags))

  		return ERR_PTR(-EINVAL);
  
  	if (attr->max_entries)
  		/* max_entries is not used and enforced to be 0 */
  		return ERR_PTR(-EINVAL);

  	ret = bpf_map_charge_init(&mem, sizeof(struct bpf_cgroup_storage_map));

  	if (ret < 0)
  		return ERR_PTR(ret);

  	map = kmalloc_node(sizeof(struct bpf_cgroup_storage_map),
  			   __GFP_ZERO | GFP_USER, numa_node);

  	if (!map) {
  		bpf_map_charge_finish(&mem);

  		return ERR_PTR(-ENOMEM);

  	}

  	bpf_map_charge_move(&map->map.memory, &mem);

  
  	/* copy mandatory map attributes */
  	bpf_map_init_from_attr(&map->map, attr);
  
  	spin_lock_init(&map->lock);
  	map->root = RB_ROOT;
  	INIT_LIST_HEAD(&map->list);
  
  	return &map->map;
  }
  
  static void cgroup_storage_map_free(struct bpf_map *_map)
  {
  	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
  
  	WARN_ON(!RB_EMPTY_ROOT(&map->root));
  	WARN_ON(!list_empty(&map->list));
  
  	kfree(map);
  }
  
  static int cgroup_storage_delete_elem(struct bpf_map *map, void *key)
  {
  	return -EINVAL;
  }

  static int cgroup_storage_check_btf(const struct bpf_map *map,
  				    const struct btf *btf,
  				    const struct btf_type *key_type,
  				    const struct btf_type *value_type)
  {

  	struct btf_member *m;

  	u32 offset, size;

  
  	/* Key is expected to be of struct bpf_cgroup_storage_key type,
  	 * which is:
  	 * struct bpf_cgroup_storage_key {
  	 *	__u64	cgroup_inode_id;
  	 *	__u32	attach_type;
  	 * };
  	 */
  
  	/*
  	 * Key_type must be a structure with two fields.
  	 */
  	if (BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT ||
  	    BTF_INFO_VLEN(key_type->info) != 2)
  		return -EINVAL;
  
  	/*
  	 * The first field must be a 64 bit integer at 0 offset.
  	 */
  	m = (struct btf_member *)(key_type + 1);

  	size = FIELD_SIZEOF(struct bpf_cgroup_storage_key, cgroup_inode_id);

  	if (!btf_member_is_reg_int(btf, key_type, m, 0, size))

  		return -EINVAL;
  
  	/*
  	 * The second field must be a 32 bit integer at 64 bit offset.
  	 */
  	m++;

  	offset = offsetof(struct bpf_cgroup_storage_key, attach_type);

  	size = FIELD_SIZEOF(struct bpf_cgroup_storage_key, attach_type);

  	if (!btf_member_is_reg_int(btf, key_type, m, offset, size))

  		return -EINVAL;
  
  	return 0;
  }
  
  static void cgroup_storage_seq_show_elem(struct bpf_map *map, void *_key,
  					 struct seq_file *m)
  {
  	enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
  	struct bpf_cgroup_storage_key *key = _key;
  	struct bpf_cgroup_storage *storage;
  	int cpu;
  
  	rcu_read_lock();
  	storage = cgroup_storage_lookup(map_to_storage(map), key, false);
  	if (!storage) {
  		rcu_read_unlock();
  		return;
  	}
  
  	btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
  	stype = cgroup_storage_type(map);
  	if (stype == BPF_CGROUP_STORAGE_SHARED) {
  		seq_puts(m, ": ");
  		btf_type_seq_show(map->btf, map->btf_value_type_id,
  				  &READ_ONCE(storage->buf)->data[0], m);
  		seq_puts(m, "
  ");
  	} else {
  		seq_puts(m, ": {
  ");
  		for_each_possible_cpu(cpu) {
  			seq_printf(m, "\tcpu%d: ", cpu);
  			btf_type_seq_show(map->btf, map->btf_value_type_id,
  					  per_cpu_ptr(storage->percpu_buf, cpu),
  					  m);
  			seq_puts(m, "
  ");
  		}
  		seq_puts(m, "}
  ");
  	}
  	rcu_read_unlock();
  }

  const struct bpf_map_ops cgroup_storage_map_ops = {
  	.map_alloc = cgroup_storage_map_alloc,
  	.map_free = cgroup_storage_map_free,
  	.map_get_next_key = cgroup_storage_get_next_key,
  	.map_lookup_elem = cgroup_storage_lookup_elem,
  	.map_update_elem = cgroup_storage_update_elem,
  	.map_delete_elem = cgroup_storage_delete_elem,

  	.map_check_btf = cgroup_storage_check_btf,
  	.map_seq_show_elem = cgroup_storage_seq_show_elem,

  };
  
  int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map)
  {

  	enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);

  	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
  	int ret = -EBUSY;
  
  	spin_lock_bh(&map->lock);
  
  	if (map->prog && map->prog != prog)
  		goto unlock;

  	if (prog->aux->cgroup_storage[stype] &&
  	    prog->aux->cgroup_storage[stype] != _map)

  		goto unlock;
  
  	map->prog = prog;

  	prog->aux->cgroup_storage[stype] = _map;

  	ret = 0;
  unlock:
  	spin_unlock_bh(&map->lock);
  
  	return ret;
  }
  
  void bpf_cgroup_storage_release(struct bpf_prog *prog, struct bpf_map *_map)
  {

  	enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);

  	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
  
  	spin_lock_bh(&map->lock);
  	if (map->prog == prog) {

  		WARN_ON(prog->aux->cgroup_storage[stype] != _map);

  		map->prog = NULL;

  		prog->aux->cgroup_storage[stype] = NULL;

  	}
  	spin_unlock_bh(&map->lock);
  }

  static size_t bpf_cgroup_storage_calculate_size(struct bpf_map *map, u32 *pages)
  {
  	size_t size;
  
  	if (cgroup_storage_type(map) == BPF_CGROUP_STORAGE_SHARED) {
  		size = sizeof(struct bpf_storage_buffer) + map->value_size;
  		*pages = round_up(sizeof(struct bpf_cgroup_storage) + size,
  				  PAGE_SIZE) >> PAGE_SHIFT;
  	} else {
  		size = map->value_size;
  		*pages = round_up(round_up(size, 8) * num_possible_cpus(),
  				  PAGE_SIZE) >> PAGE_SHIFT;
  	}
  
  	return size;
  }

  struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,
  					enum bpf_cgroup_storage_type stype)

  {
  	struct bpf_cgroup_storage *storage;
  	struct bpf_map *map;

  	gfp_t flags;
  	size_t size;

  	u32 pages;

  	map = prog->aux->cgroup_storage[stype];

  	if (!map)
  		return NULL;

  	size = bpf_cgroup_storage_calculate_size(map, &pages);

  	if (bpf_map_charge_memlock(map, pages))
  		return ERR_PTR(-EPERM);
  
  	storage = kmalloc_node(sizeof(struct bpf_cgroup_storage),
  			       __GFP_ZERO | GFP_USER, map->numa_node);

  	if (!storage)
  		goto enomem;

  	flags = __GFP_ZERO | GFP_USER;
  
  	if (stype == BPF_CGROUP_STORAGE_SHARED) {
  		storage->buf = kmalloc_node(size, flags, map->numa_node);
  		if (!storage->buf)
  			goto enomem;

  		check_and_init_map_lock(map, storage->buf->data);

  	} else {
  		storage->percpu_buf = __alloc_percpu_gfp(size, 8, flags);
  		if (!storage->percpu_buf)
  			goto enomem;

  	}
  
  	storage->map = (struct bpf_cgroup_storage_map *)map;
  
  	return storage;

  
  enomem:
  	bpf_map_uncharge_memlock(map, pages);
  	kfree(storage);
  	return ERR_PTR(-ENOMEM);
  }
  
  static void free_shared_cgroup_storage_rcu(struct rcu_head *rcu)
  {
  	struct bpf_cgroup_storage *storage =
  		container_of(rcu, struct bpf_cgroup_storage, rcu);
  
  	kfree(storage->buf);
  	kfree(storage);
  }
  
  static void free_percpu_cgroup_storage_rcu(struct rcu_head *rcu)
  {
  	struct bpf_cgroup_storage *storage =
  		container_of(rcu, struct bpf_cgroup_storage, rcu);
  
  	free_percpu(storage->percpu_buf);
  	kfree(storage);

  }
  
  void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage)
  {

  	enum bpf_cgroup_storage_type stype;

  	struct bpf_map *map;

  	u32 pages;

  
  	if (!storage)
  		return;
  
  	map = &storage->map->map;

  
  	bpf_cgroup_storage_calculate_size(map, &pages);

  	bpf_map_uncharge_memlock(map, pages);

  	stype = cgroup_storage_type(map);
  	if (stype == BPF_CGROUP_STORAGE_SHARED)
  		call_rcu(&storage->rcu, free_shared_cgroup_storage_rcu);
  	else
  		call_rcu(&storage->rcu, free_percpu_cgroup_storage_rcu);

  }
  
  void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
  			     struct cgroup *cgroup,
  			     enum bpf_attach_type type)
  {
  	struct bpf_cgroup_storage_map *map;
  
  	if (!storage)
  		return;
  
  	storage->key.attach_type = type;
  	storage->key.cgroup_inode_id = cgroup->kn->id.id;
  
  	map = storage->map;
  
  	spin_lock_bh(&map->lock);
  	WARN_ON(cgroup_storage_insert(map, storage));
  	list_add(&storage->list, &map->list);
  	spin_unlock_bh(&map->lock);
  }
  
  void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage)
  {
  	struct bpf_cgroup_storage_map *map;
  	struct rb_root *root;
  
  	if (!storage)
  		return;
  
  	map = storage->map;
  
  	spin_lock_bh(&map->lock);
  	root = &map->root;
  	rb_erase(&storage->node, root);
  
  	list_del(&storage->list);
  	spin_unlock_bh(&map->lock);
  }
  
  #endif