path: root/net/core/bpf_sk_storage.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019 Facebook  */
#include <linux/rculist.h>
#include <linux/list.h>
#include <linux/hash.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/btf_ids.h>
#include <linux/bpf_local_storage.h>
#include <net/bpf_sk_storage.h>
#include <net/sock.h>
#include <uapi/linux/sock_diag.h>
#include <uapi/linux/btf.h>
#include <linux/rcupdate_trace.h>

DEFINE_BPF_STORAGE_CACHE(sk_cache);

static struct bpf_local_storage_data *
bpf_sk_storage_lookup(struct sock *sk, struct bpf_map *map, bool cacheit_lockit)
{
	struct bpf_local_storage *sk_storage;
	struct bpf_local_storage_map *smap;

	sk_storage =
		rcu_dereference_check(sk->sk_bpf_storage, bpf_rcu_lock_held());
	if (!sk_storage)
		return NULL;

	smap = (struct bpf_local_storage_map *)map;
	return bpf_local_storage_lookup(sk_storage, smap, cacheit_lockit);
}

static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map)
{
	struct bpf_local_storage_data *sdata;

	sdata = bpf_sk_storage_lookup(sk, map, false);
	if (!sdata)
		return -ENOENT;

	bpf_selem_unlink(SELEM(sdata), false);

	return 0;
}

/* Called by __sk_destruct() & bpf_sk_storage_clone() */
void bpf_sk_storage_free(struct sock *sk)
{
	struct bpf_local_storage *sk_storage;

	rcu_read_lock_dont_migrate();
	sk_storage = rcu_dereference(sk->sk_bpf_storage);
	if (!sk_storage)
		goto out;

	bpf_local_storage_destroy(sk_storage);
out:
	rcu_read_unlock_migrate();
}

static void bpf_sk_storage_map_free(struct bpf_map *map)
{
	bpf_local_storage_map_free(map, &sk_cache, NULL);
}

static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr)
{
	return bpf_local_storage_map_alloc(attr, &sk_cache, false);
}

static int notsupp_get_next_key(struct bpf_map *map, void *key,
				void *next_key)
{
	return -ENOTSUPP;
}

static void *bpf_fd_sk_storage_lookup_elem(struct bpf_map *map, void *key)
{
	struct bpf_local_storage_data *sdata;
	struct socket *sock;
	int fd, err;

	fd = *(int *)key;
	sock = sockfd_lookup(fd, &err);
	if (sock) {
		sdata = bpf_sk_storage_lookup(sock->sk, map, true);
		sockfd_put(sock);
		return sdata ? sdata->data : NULL;
	}

	return ERR_PTR(err);
}

static long bpf_fd_sk_storage_update_elem(struct bpf_map *map, void *key,
					  void *value, u64 map_flags)
{
	struct bpf_local_storage_data *sdata;
	struct socket *sock;
	int fd, err;

	fd = *(int *)key;
	sock = sockfd_lookup(fd, &err);
	if (sock) {
		sdata = bpf_local_storage_update(
			sock->sk, (struct bpf_local_storage_map *)map, value,
			map_flags, false, GFP_ATOMIC);
		sockfd_put(sock);
		return PTR_ERR_OR_ZERO(sdata);
	}

	return err;
}

static long bpf_fd_sk_storage_delete_elem(struct bpf_map *map, void *key)
{
	struct socket *sock;
	int fd, err;

	fd = *(int *)key;
	sock = sockfd_lookup(fd, &err);
	if (sock) {
		err = bpf_sk_storage_del(sock->sk, map);
		sockfd_put(sock);
		return err;
	}

	return err;
}

static struct bpf_local_storage_elem *
bpf_sk_storage_clone_elem(struct sock *newsk,
			  struct bpf_local_storage_map *smap,
			  struct bpf_local_storage_elem *selem)
{
	struct bpf_local_storage_elem *copy_selem;

	copy_selem = bpf_selem_alloc(smap, newsk, NULL, false, GFP_ATOMIC);
	if (!copy_selem)
		return NULL;

	if (btf_record_has_field(smap->map.record, BPF_SPIN_LOCK))
		copy_map_value_locked(&smap->map, SDATA(copy_selem)->data,
				      SDATA(selem)->data, true);
	else
		copy_map_value(&smap->map, SDATA(copy_selem)->data,
			       SDATA(selem)->data);

	return copy_selem;
}

int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
{
	struct bpf_local_storage *new_sk_storage = NULL;
	struct bpf_local_storage *