kernel/bpf/offload.c - third_party/linux - Git at Google

 /*
  * Copyright (C) 2017-2018 Netronome Systems, Inc.
  *
  * This software is licensed under the GNU General License Version 2,
  * June 1991 as shown in the file COPYING in the top-level directory of this
  * source tree.
  *
  * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
  * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
  * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
  * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
  */

 #include <linux/bpf.h>
 #include <linux/bpf_verifier.h>
 #include <linux/bug.h>
 #include <linux/kdev_t.h>
 #include <linux/list.h>
 #include <linux/lockdep.h>
 #include <linux/netdevice.h>
 #include <linux/printk.h>
 #include <linux/proc_ns.h>
 #include <linux/rhashtable.h>
 #include <linux/rtnetlink.h>
 #include <linux/rwsem.h>

 /* Protects offdevs, members of bpf_offload_netdev and offload members
  * of all progs.
  * RTNL lock cannot be taken when holding this lock.
  */
 static DECLARE_RWSEM(bpf_devs_lock);

 struct bpf_offload_dev {
 	const struct bpf_prog_offload_ops *ops;
 	struct list_head netdevs;
 	void *priv;
 };

 struct bpf_offload_netdev {
 	struct rhash_head l;
 	struct net_device *netdev;
 	struct bpf_offload_dev *offdev;
 	struct list_head progs;
 	struct list_head maps;
 	struct list_head offdev_netdevs;
 };

 static const struct rhashtable_params offdevs_params = {
 	.nelem_hint		= 4,
 	.key_len		= sizeof(struct net_device *),
 	.key_offset		= offsetof(struct bpf_offload_netdev, netdev),
 	.head_offset		= offsetof(struct bpf_offload_netdev, l),
 	.automatic_shrinking	= true,
 };

 static struct rhashtable offdevs;
 static bool offdevs_inited;

 static int bpf_dev_offload_check(struct net_device *netdev)
 {
 	if (!netdev)
 		return -EINVAL;
 	if (!netdev->netdev_ops->ndo_bpf)
 		return -EOPNOTSUPP;
 	return 0;
 }

 static struct bpf_offload_netdev *
 bpf_offload_find_netdev(struct net_device *netdev)
 {
 	lockdep_assert_held(&bpf_devs_lock);

 	if (!offdevs_inited)
 		return NULL;
 	return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
 }

 int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
 {
 	struct bpf_offload_netdev *ondev;
 	struct bpf_prog_offload *offload;
 	int err;

 	if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS &&
 	    attr->prog_type != BPF_PROG_TYPE_XDP)
 		return -EINVAL;

 	if (attr->prog_flags)
 		return -EINVAL;

 	offload = kzalloc(sizeof(*offload), GFP_USER);
 	if (!offload)
 		return -ENOMEM;

 	offload->prog = prog;

 	offload->netdev = dev_get_by_index(current->nsproxy->net_ns,
 					   attr->prog_ifindex);
 	err = bpf_dev_offload_check(offload->netdev);
 	if (err)
 		goto err_maybe_put;

 	down_write(&bpf_devs_lock);
 	ondev = bpf_offload_find_netdev(offload->netdev);
 	if (!ondev) {
 		err = -EINVAL;
 		goto err_unlock;
 	}
 	offload->offdev = ondev->offdev;
 	prog->aux->offload = offload;
 	list_add_tail(&offload->offloads, &ondev->progs);
 	dev_put(offload->netdev);
 	up_write(&bpf_devs_lock);

 	return 0;
 err_unlock:
 	up_write(&bpf_devs_lock);
 err_maybe_put:
 	if (offload->netdev)
 		dev_put(offload->netdev);
 	kfree(offload);
 	return err;
 }

 int bpf_prog_offload_verifier_prep(struct bpf_prog *prog)
 {
 	struct bpf_prog_offload *offload;
 	int ret = -ENODEV;

 	down_read(&bpf_devs_lock);
 	offload = prog->aux->offload;
 	if (offload) {
 		ret = offload->offdev->ops->prepare(prog);
 		offload->dev_state = !ret;
 	}
 	up_read(&bpf_devs_lock);

 	return ret;
 }

 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
 				 int insn_idx, int prev_insn_idx)
 {
 	struct bpf_prog_offload *offload;
 	int ret = -ENODEV;

 	down_read(&bpf_devs_lock);
 	offload = env->prog->aux->offload;
 	if (offload)
 		ret = offload->offdev->ops->insn_hook(env, insn_idx,
 						      prev_insn_idx);
 	up_read(&bpf_devs_lock);

 	return ret;
 }

 int bpf_prog_offload_finalize(struct bpf_verifier_env *env)
 {
 	struct bpf_prog_offload *offload;
 	int ret = -ENODEV;

 	down_read(&bpf_devs_lock);
 	offload = env->prog->aux->offload;
 	if (offload) {
 		if (offload->offdev->ops->finalize)
 			ret = offload->offdev->ops->finalize(env);
 		else
 			ret = 0;
 	}
 	up_read(&bpf_devs_lock);

 	return ret;
 }

 void
 bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
 			      struct bpf_insn *insn)
 {
 	const struct bpf_prog_offload_ops *ops;
 	struct bpf_prog_offload *offload;
 	int ret = -EOPNOTSUPP;

 	down_read(&bpf_devs_lock);
 	offload = env->prog->aux->offload;
 	if (offload) {
 		ops = offload->offdev->ops;
 		if (!offload->opt_failed && ops->replace_insn)
 			ret = ops->replace_insn(env, off, insn);
 		offload->opt_failed |= ret;
 	}
 	up_read(&bpf_devs_lock);
 }

 void
 bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
 {
 	struct bpf_prog_offload *offload;
 	int ret = -EOPNOTSUPP;

 	down_read(&bpf_devs_lock);
 	offload = env->prog->aux->offload;
 	if (offload) {
 		if (!offload->opt_failed && offload->offdev->ops->remove_insns)
 			ret = offload->offdev->ops->remove_insns(env, off, cnt);
 		offload->opt_failed |= ret;
 	}
 	up_read(&bpf_devs_lock);
 }

 static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
 {
 	struct bpf_prog_offload *offload = prog->aux->offload;

 	if (offload->dev_state)
 		offload->offdev->ops->destroy(prog);

 	/* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */
 	bpf_prog_free_id(prog, true);

 	list_del_init(&offload->offloads);
 	kfree(offload);
 	prog->aux->offload = NULL;
 }

 void bpf_prog_offload_destroy(struct bpf_prog *prog)
 {
 	down_write(&bpf_devs_lock);
 	if (prog->aux->offload)
 		__bpf_prog_offload_destroy(prog);
 	up_write(&bpf_devs_lock);
 }

 static int bpf_prog_offload_translate(struct bpf_prog *prog)
 {
 	struct bpf_prog_offload *offload;
 	int ret = -ENODEV;

 	down_read(&bpf_devs_lock);
 	offload = prog->aux->offload;
 	if (offload)
 		ret = offload->offdev->ops->translate(prog);
 	up_read(&bpf_devs_lock);

 	return ret;
 }

 static unsigned int bpf_prog_warn_on_exec(const void *ctx,
 					  const struct bpf_insn *insn)
 {
 	WARN(1, "attempt to execute device eBPF program on the host!");
 	return 0;
 }

 int bpf_prog_offload_compile(struct bpf_prog *prog)
 {
 	prog->bpf_func = bpf_prog_warn_on_exec;

 	return bpf_prog_offload_translate(prog);
 }

 struct ns_get_path_bpf_prog_args {
 	struct bpf_prog *prog;
 	struct bpf_prog_info *info;
 };

 static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data)
 {
 	struct ns_get_path_bpf_prog_args *args = private_data;
 	struct bpf_prog_aux *aux = args->prog->aux;
 	struct ns_common *ns;
 	struct net *net;

 	rtnl_lock();
 	down_read(&bpf_devs_lock);

 	if (aux->offload) {
 		args->info->ifindex = aux->offload->netdev->ifindex;
 		net = dev_net(aux->offload->netdev);
 		get_net(net);
 		ns = &net->ns;
 	} else {
 		args->info->ifindex = 0;
 		ns = NULL;
 	}

 	up_read(&bpf_devs_lock);
 	rtnl_unlock();

 	return ns;
 }

 int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
 			       struct bpf_prog *prog)
 {
 	struct ns_get_path_bpf_prog_args args = {
 		.prog	= prog,
 		.info	= info,
 	};
 	struct bpf_prog_aux *aux = prog->aux;
 	struct inode *ns_inode;
 	struct path ns_path;
 	char __user *uinsns;
 	int res;
 	u32 ulen;

 	res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
 	if (res) {
 		if (!info->ifindex)
 			return -ENODEV;
 		return res;
 	}

 	down_read(&bpf_devs_lock);

 	if (!aux->offload) {
 		up_read(&bpf_devs_lock);
 		return -ENODEV;
 	}

 	ulen = info->jited_prog_len;
 	info->jited_prog_len = aux->offload->jited_len;
 	if (info->jited_prog_len && ulen) {
 		uinsns = u64_to_user_ptr(info->jited_prog_insns);
 		ulen = min_t(u32, info->jited_prog_len, ulen);
 		if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {
 			up_read(&bpf_devs_lock);
 			return -EFAULT;
 		}
 	}

 	up_read(&bpf_devs_lock);

 	ns_inode = ns_path.dentry->d_inode;
 	info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
 	info->netns_ino = ns_inode->i_ino;
 	path_put(&ns_path);

 	return 0;
 }

 const struct bpf_prog_ops bpf_offload_prog_ops = {
 };

 static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap,
 			       enum bpf_netdev_command cmd)
 {
 	struct netdev_bpf data = {};
 	struct net_device *netdev;

 	ASSERT_RTNL();

 	data.command = cmd;
 	data.offmap = offmap;
 	/* Caller must make sure netdev is valid */
 	netdev = offmap->netdev;

 	return netdev->netdev_ops->ndo_bpf(netdev, &data);
 }

 struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr)
 {
 	struct net *net = current->nsproxy->net_ns;
 	struct bpf_offload_netdev *ondev;
 	struct bpf_offloaded_map *offmap;
 	int err;

 	if (!capable(CAP_SYS_ADMIN))
 		return ERR_PTR(-EPERM);
 	if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
 	    attr->map_type != BPF_MAP_TYPE_HASH)
 		return ERR_PTR(-EINVAL);

 	offmap = bpf_map_area_alloc(sizeof(*offmap), NUMA_NO_NODE);
 	if (!offmap)
 		return ERR_PTR(-ENOMEM);

 	bpf_map_init_from_attr(&offmap->map, attr);

 	rtnl_lock();
 	down_write(&bpf_devs_lock);
 	offmap->netdev = __dev_get_by_index(net, attr->map_ifindex);
 	err = bpf_dev_offload_check(offmap->netdev);
 	if (err)
 		goto err_unlock;

 	ondev = bpf_offload_find_netdev(offmap->netdev);
 	if (!ondev) {
 		err = -EINVAL;
 		goto err_unlock;
 	}

 	err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC);
 	if (err)
 		goto err_unlock;

 	list_add_tail(&offmap->offloads, &ondev->maps);
 	up_write(&bpf_devs_lock);
 	rtnl_unlock();

 	return &offmap->map;

 err_unlock:
 	up_write(&bpf_devs_lock);
 	rtnl_unlock();
 	bpf_map_area_free(offmap);
 	return ERR_PTR(err);
 }

 static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap)
 {
 	WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE));
 	/* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */
 	bpf_map_free_id(&offmap->map, true);
 	list_del_init(&offmap->offloads);
 	offmap->netdev = NULL;
 }

 void bpf_map_offload_map_free(struct bpf_map *map)
 {
 	struct bpf_offloaded_map *offmap = map_to_offmap(map);

 	rtnl_lock();
 	down_write(&bpf_devs_lock);
 	if (offmap->netdev)
 		__bpf_map_offload_destroy(offmap);
 	up_write(&bpf_devs_lock);
 	rtnl_unlock();

 	bpf_map_area_free(offmap);
 }

 int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value)
 {
 	struct bpf_offloaded_map *offmap = map_to_offmap(map);
 	int ret = -ENODEV;

 	down_read(&bpf_devs_lock);
 	if (offmap->netdev)
 		ret = offmap->dev_ops->map_lookup_elem(offmap, key, value);
 	up_read(&bpf_devs_lock);

 	return ret;
 }

 int bpf_map_offload_update_elem(struct bpf_map *map,
 				void *key, void *value, u64 flags)
 {
 	struct bpf_offloaded_map *offmap = map_to_offmap(map);
 	int ret = -ENODEV;

 	if (unlikely(flags > BPF_EXIST))
 		return -EINVAL;

 	down_read(&bpf_devs_lock);
 	if (offmap->netdev)
 		ret = offmap->dev_ops->map_update_elem(offmap, key, value,
 						       flags);
 	up_read(&bpf_devs_lock);

 	return ret;
 }

 int bpf_map_offload_delete_elem(struct bpf_map *map, void *key)
 {
 	struct bpf_offloaded_map *offmap = map_to_offmap(map);
 	int ret = -ENODEV;

 	down_read(&bpf_devs_lock);
 	if (offmap->netdev)
 		ret = offmap->dev_ops->map_delete_elem(offmap, key);
 	up_read(&bpf_devs_lock);

 	return ret;
 }

 int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key)
 {
 	struct bpf_offloaded_map *offmap = map_to_offmap(map);
 	int ret = -ENODEV;

 	down_read(&bpf_devs_lock);
 	if (offmap->netdev)
 		ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key);
 	up_read(&bpf_devs_lock);

 	return ret;
 }

 struct ns_get_path_bpf_map_args {
 	struct bpf_offloaded_map *offmap;
 	struct bpf_map_info *info;
 };

 static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data)
 {
 	struct ns_get_path_bpf_map_args *args = private_data;
 	struct ns_common *ns;
 	struct net *net;

 	rtnl_lock();
 	down_read(&bpf_devs_lock);

 	if (args->offmap->netdev) {
 		args->info->ifindex = args->offmap->netdev->ifindex;
 		net = dev_net(args->offmap->netdev);
 		get_net(net);
 		ns = &net->ns;
 	} else {
 		args->info->ifindex = 0;
 		ns = NULL;
 	}

 	up_read(&bpf_devs_lock);
 	rtnl_unlock();

 	return ns;
 }

 int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map)
 {
 	struct ns_get_path_bpf_map_args args = {
 		.offmap	= map_to_offmap(map),
 		.info	= info,
 	};
 	struct inode *ns_inode;
 	struct path ns_path;
 	int res;

 	res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
 	if (res) {
 		if (!info->ifindex)
 			return -ENODEV;
 		return res;
 	}

 	ns_inode = ns_path.dentry->d_inode;
 	info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
 	info->netns_ino = ns_inode->i_ino;
 	path_put(&ns_path);

 	return 0;
 }

 static bool __bpf_offload_dev_match(struct bpf_prog *prog,
 				    struct net_device *netdev)
 {
 	struct bpf_offload_netdev *ondev1, *ondev2;
 	struct bpf_prog_offload *offload;

 	if (!bpf_prog_is_dev_bound(prog->aux))
 		return false;

 	offload = prog->aux->offload;
 	if (!offload)
 		return false;
 	if (offload->netdev == netdev)
 		return true;

 	ondev1 = bpf_offload_find_netdev(offload->netdev);
 	ondev2 = bpf_offload_find_netdev(netdev);

 	return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev;
 }

 bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev)
 {
 	bool ret;

 	down_read(&bpf_devs_lock);
 	ret = __bpf_offload_dev_match(prog, netdev);
 	up_read(&bpf_devs_lock);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(bpf_offload_dev_match);

 bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map)
 {
 	struct bpf_offloaded_map *offmap;
 	bool ret;

 	if (!bpf_map_is_dev_bound(map))
 		return bpf_map_offload_neutral(map);
 	offmap = map_to_offmap(map);

 	down_read(&bpf_devs_lock);
 	ret = __bpf_offload_dev_match(prog, offmap->netdev);
 	up_read(&bpf_devs_lock);

 	return ret;
 }

 int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
 				    struct net_device *netdev)
 {
 	struct bpf_offload_netdev *ondev;
 	int err;

 	ondev = kzalloc(sizeof(*ondev), GFP_KERNEL);
 	if (!ondev)
 		return -ENOMEM;

 	ondev->netdev = netdev;
 	ondev->offdev = offdev;
 	INIT_LIST_HEAD(&ondev->progs);
 	INIT_LIST_HEAD(&ondev->maps);

 	down_write(&bpf_devs_lock);
 	err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params);
 	if (err) {
 		netdev_warn(netdev, "failed to register for BPF offload\n");
 		goto err_unlock_free;
 	}

 	list_add(&ondev->offdev_netdevs, &offdev->netdevs);
 	up_write(&bpf_devs_lock);
 	return 0;

 err_unlock_free:
 	up_write(&bpf_devs_lock);
 	kfree(ondev);
 	return err;
 }
 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register);

 void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
 				       struct net_device *netdev)
 {
 	struct bpf_offload_netdev *ondev, *altdev;
 	struct bpf_offloaded_map *offmap, *mtmp;
 	struct bpf_prog_offload *offload, *ptmp;

 	ASSERT_RTNL();

 	down_write(&bpf_devs_lock);
 	ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
 	if (WARN_ON(!ondev))
 		goto unlock;

 	WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params));
 	list_del(&ondev->offdev_netdevs);

 	/* Try to move the objects to another netdev of the device */
 	altdev = list_first_entry_or_null(&offdev->netdevs,
 					  struct bpf_offload_netdev,
 					  offdev_netdevs);
 	if (altdev) {
 		list_for_each_entry(offload, &ondev->progs, offloads)
 			offload->netdev = altdev->netdev;
 		list_splice_init(&ondev->progs, &altdev->progs);

 		list_for_each_entry(offmap, &ondev->maps, offloads)
 			offmap->netdev = altdev->netdev;
 		list_splice_init(&ondev->maps, &altdev->maps);
 	} else {
 		list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads)
 			__bpf_prog_offload_destroy(offload->prog);
 		list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads)
 			__bpf_map_offload_destroy(offmap);
 	}

 	WARN_ON(!list_empty(&ondev->progs));
 	WARN_ON(!list_empty(&ondev->maps));
 	kfree(ondev);
 unlock:
 	up_write(&bpf_devs_lock);
 }
 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister);

 struct bpf_offload_dev *
 bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops, void *priv)
 {
 	struct bpf_offload_dev *offdev;
 	int err;

 	down_write(&bpf_devs_lock);
 	if (!offdevs_inited) {
 		err = rhashtable_init(&offdevs, &offdevs_params);
 		if (err) {
 			up_write(&bpf_devs_lock);
 			return ERR_PTR(err);
 		}
 		offdevs_inited = true;
 	}
 	up_write(&bpf_devs_lock);

 	offdev = kzalloc(sizeof(*offdev), GFP_KERNEL);
 	if (!offdev)
 		return ERR_PTR(-ENOMEM);

 	offdev->ops = ops;
 	offdev->priv = priv;
 	INIT_LIST_HEAD(&offdev->netdevs);

 	return offdev;
 }
 EXPORT_SYMBOL_GPL(bpf_offload_dev_create);

 void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev)
 {
 	WARN_ON(!list_empty(&offdev->netdevs));
 	kfree(offdev);
 }
 EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy);

 void *bpf_offload_dev_priv(struct bpf_offload_dev *offdev)
 {
 	return offdev->priv;
 }
 EXPORT_SYMBOL_GPL(bpf_offload_dev_priv);
	/*
	* Copyright (C) 2017-2018 Netronome Systems, Inc.
	*
	* This software is licensed under the GNU General License Version 2,
	* June 1991 as shown in the file COPYING in the top-level directory of this
	* source tree.
	*
	* THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
	* WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
	* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
	* FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
	* OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
	* THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
	*/

	#include <linux/bpf.h>
	#include <linux/bpf_verifier.h>
	#include <linux/bug.h>
	#include <linux/kdev_t.h>
	#include <linux/list.h>
	#include <linux/lockdep.h>
	#include <linux/netdevice.h>
	#include <linux/printk.h>
	#include <linux/proc_ns.h>
	#include <linux/rhashtable.h>
	#include <linux/rtnetlink.h>
	#include <linux/rwsem.h>

	/* Protects offdevs, members of bpf_offload_netdev and offload members
	* of all progs.
	* RTNL lock cannot be taken when holding this lock.
	*/
	static DECLARE_RWSEM(bpf_devs_lock);

	struct bpf_offload_dev {
	const struct bpf_prog_offload_ops *ops;
	struct list_head netdevs;
	void *priv;
	};

	struct bpf_offload_netdev {
	struct rhash_head l;
	struct net_device *netdev;
	struct bpf_offload_dev *offdev;
	struct list_head progs;
	struct list_head maps;
	struct list_head offdev_netdevs;
	};

	static const struct rhashtable_params offdevs_params = {
	.nelem_hint = 4,
	.key_len = sizeof(struct net_device *),
	.key_offset = offsetof(struct bpf_offload_netdev, netdev),
	.head_offset = offsetof(struct bpf_offload_netdev, l),
	.automatic_shrinking = true,
	};

	static struct rhashtable offdevs;
	static bool offdevs_inited;

	static int bpf_dev_offload_check(struct net_device *netdev)
	{
	if (!netdev)
	return -EINVAL;
	if (!netdev->netdev_ops->ndo_bpf)
	return -EOPNOTSUPP;
	return 0;
	}

	static struct bpf_offload_netdev *
	bpf_offload_find_netdev(struct net_device *netdev)
	{
	lockdep_assert_held(&bpf_devs_lock);

	if (!offdevs_inited)
	return NULL;
	return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
	}

	int bpf_prog_offload_init(struct bpf_prog prog, union bpf_attr attr)
	{
	struct bpf_offload_netdev *ondev;
	struct bpf_prog_offload *offload;
	int err;

	if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS &&
	attr->prog_type != BPF_PROG_TYPE_XDP)
	return -EINVAL;

	if (attr->prog_flags)
	return -EINVAL;

	offload = kzalloc(sizeof(*offload), GFP_USER);
	if (!offload)
	return -ENOMEM;

	offload->prog = prog;

	offload->netdev = dev_get_by_index(current->nsproxy->net_ns,
	attr->prog_ifindex);
	err = bpf_dev_offload_check(offload->netdev);
	if (err)
	goto err_maybe_put;

	down_write(&bpf_devs_lock);
	ondev = bpf_offload_find_netdev(offload->netdev);
	if (!ondev) {
	err = -EINVAL;
	goto err_unlock;
	}
	offload->offdev = ondev->offdev;
	prog->aux->offload = offload;
	list_add_tail(&offload->offloads, &ondev->progs);
	dev_put(offload->netdev);
	up_write(&bpf_devs_lock);

	return 0;
	err_unlock:
	up_write(&bpf_devs_lock);
	err_maybe_put:
	if (offload->netdev)
	dev_put(offload->netdev);
	kfree(offload);
	return err;
	}

	int bpf_prog_offload_verifier_prep(struct bpf_prog *prog)
	{
	struct bpf_prog_offload *offload;
	int ret = -ENODEV;

	down_read(&bpf_devs_lock);
	offload = prog->aux->offload;
	if (offload) {
	ret = offload->offdev->ops->prepare(prog);
	offload->dev_state = !ret;
	}
	up_read(&bpf_devs_lock);

	return ret;
	}

	int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
	int insn_idx, int prev_insn_idx)
	{
	struct bpf_prog_offload *offload;
	int ret = -ENODEV;

	down_read(&bpf_devs_lock);
	offload = env->prog->aux->offload;
	if (offload)
	ret = offload->offdev->ops->insn_hook(env, insn_idx,
	prev_insn_idx);
	up_read(&bpf_devs_lock);

	return ret;
	}

	int bpf_prog_offload_finalize(struct bpf_verifier_env *env)
	{
	struct bpf_prog_offload *offload;
	int ret = -ENODEV;

	down_read(&bpf_devs_lock);
	offload = env->prog->aux->offload;
	if (offload) {
	if (offload->offdev->ops->finalize)
	ret = offload->offdev->ops->finalize(env);
	else
	ret = 0;
	}
	up_read(&bpf_devs_lock);

	return ret;
	}

	void
	bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
	struct bpf_insn *insn)
	{
	const struct bpf_prog_offload_ops *ops;
	struct bpf_prog_offload *offload;
	int ret = -EOPNOTSUPP;

	down_read(&bpf_devs_lock);
	offload = env->prog->aux->offload;
	if (offload) {
	ops = offload->offdev->ops;
	if (!offload->opt_failed && ops->replace_insn)
	ret = ops->replace_insn(env, off, insn);
	offload->opt_failed \|= ret;
	}
	up_read(&bpf_devs_lock);
	}

	void
	bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
	{
	struct bpf_prog_offload *offload;
	int ret = -EOPNOTSUPP;

	down_read(&bpf_devs_lock);
	offload = env->prog->aux->offload;
	if (offload) {
	if (!offload->opt_failed && offload->offdev->ops->remove_insns)
	ret = offload->offdev->ops->remove_insns(env, off, cnt);
	offload->opt_failed \|= ret;
	}
	up_read(&bpf_devs_lock);
	}

	static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
	{
	struct bpf_prog_offload *offload = prog->aux->offload;

	if (offload->dev_state)
	offload->offdev->ops->destroy(prog);

	/* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */
	bpf_prog_free_id(prog, true);

	list_del_init(&offload->offloads);
	kfree(offload);
	prog->aux->offload = NULL;
	}

	void bpf_prog_offload_destroy(struct bpf_prog *prog)
	{
	down_write(&bpf_devs_lock);
	if (prog->aux->offload)
	__bpf_prog_offload_destroy(prog);
	up_write(&bpf_devs_lock);
	}

	static int bpf_prog_offload_translate(struct bpf_prog *prog)
	{
	struct bpf_prog_offload *offload;
	int ret = -ENODEV;

	down_read(&bpf_devs_lock);
	offload = prog->aux->offload;
	if (offload)
	ret = offload->offdev->ops->translate(prog);
	up_read(&bpf_devs_lock);

	return ret;
	}

	static unsigned int bpf_prog_warn_on_exec(const void *ctx,
	const struct bpf_insn *insn)
	{
	WARN(1, "attempt to execute device eBPF program on the host!");
	return 0;
	}

	int bpf_prog_offload_compile(struct bpf_prog *prog)
	{
	prog->bpf_func = bpf_prog_warn_on_exec;

	return bpf_prog_offload_translate(prog);
	}

	struct ns_get_path_bpf_prog_args {
	struct bpf_prog *prog;
	struct bpf_prog_info *info;
	};

	static struct ns_common bpf_prog_offload_info_fill_ns(void private_data)
	{
	struct ns_get_path_bpf_prog_args *args = private_data;
	struct bpf_prog_aux *aux = args->prog->aux;
	struct ns_common *ns;
	struct net *net;

	rtnl_lock();
	down_read(&bpf_devs_lock);

	if (aux->offload) {
	args->info->ifindex = aux->offload->netdev->ifindex;
	net = dev_net(aux->offload->netdev);
	get_net(net);
	ns = &net->ns;
	} else {
	args->info->ifindex = 0;
	ns = NULL;
	}

	up_read(&bpf_devs_lock);
	rtnl_unlock();

	return ns;
	}

	int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
	struct bpf_prog *prog)
	{
	struct ns_get_path_bpf_prog_args args = {
	.prog = prog,
	.info = info,
	};
	struct bpf_prog_aux *aux = prog->aux;
	struct inode *ns_inode;
	struct path ns_path;
	char __user *uinsns;
	int res;
	u32 ulen;

	res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
	if (res) {
	if (!info->ifindex)
	return -ENODEV;
	return res;
	}

	down_read(&bpf_devs_lock);

	if (!aux->offload) {
	up_read(&bpf_devs_lock);
	return -ENODEV;
	}

	ulen = info->jited_prog_len;
	info->jited_prog_len = aux->offload->jited_len;
	if (info->jited_prog_len && ulen) {
	uinsns = u64_to_user_ptr(info->jited_prog_insns);
	ulen = min_t(u32, info->jited_prog_len, ulen);
	if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {
	up_read(&bpf_devs_lock);
	return -EFAULT;
	}
	}

	up_read(&bpf_devs_lock);

	ns_inode = ns_path.dentry->d_inode;
	info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
	info->netns_ino = ns_inode->i_ino;
	path_put(&ns_path);

	return 0;
	}

	const struct bpf_prog_ops bpf_offload_prog_ops = {
	};

	static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap,
	enum bpf_netdev_command cmd)
	{
	struct netdev_bpf data = {};
	struct net_device *netdev;

	ASSERT_RTNL();

	data.command = cmd;
	data.offmap = offmap;
	/* Caller must make sure netdev is valid */
	netdev = offmap->netdev;

	return netdev->netdev_ops->ndo_bpf(netdev, &data);
	}

	struct bpf_map bpf_map_offload_map_alloc(union bpf_attr attr)
	{
	struct net *net = current->nsproxy->net_ns;
	struct bpf_offload_netdev *ondev;
	struct bpf_offloaded_map *offmap;
	int err;

	if (!capable(CAP_SYS_ADMIN))
	return ERR_PTR(-EPERM);
	if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
	attr->map_type != BPF_MAP_TYPE_HASH)
	return ERR_PTR(-EINVAL);

	offmap = bpf_map_area_alloc(sizeof(*offmap), NUMA_NO_NODE);
	if (!offmap)
	return ERR_PTR(-ENOMEM);

	bpf_map_init_from_attr(&offmap->map, attr);

	rtnl_lock();
	down_write(&bpf_devs_lock);
	offmap->netdev = __dev_get_by_index(net, attr->map_ifindex);
	err = bpf_dev_offload_check(offmap->netdev);
	if (err)
	goto err_unlock;

	ondev = bpf_offload_find_netdev(offmap->netdev);
	if (!ondev) {
	err = -EINVAL;
	goto err_unlock;
	}

	err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC);
	if (err)
	goto err_unlock;

	list_add_tail(&offmap->offloads, &ondev->maps);
	up_write(&bpf_devs_lock);
	rtnl_unlock();

	return &offmap->map;

	err_unlock:
	up_write(&bpf_devs_lock);
	rtnl_unlock();
	bpf_map_area_free(offmap);
	return ERR_PTR(err);
	}

	static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap)
	{
	WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE));
	/* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */
	bpf_map_free_id(&offmap->map, true);
	list_del_init(&offmap->offloads);
	offmap->netdev = NULL;
	}

	void bpf_map_offload_map_free(struct bpf_map *map)
	{
	struct bpf_offloaded_map *offmap = map_to_offmap(map);

	rtnl_lock();
	down_write(&bpf_devs_lock);
	if (offmap->netdev)
	__bpf_map_offload_destroy(offmap);
	up_write(&bpf_devs_lock);
	rtnl_unlock();

	bpf_map_area_free(offmap);
	}

	int bpf_map_offload_lookup_elem(struct bpf_map map, void key, void *value)
	{
	struct bpf_offloaded_map *offmap = map_to_offmap(map);
	int ret = -ENODEV;

	down_read(&bpf_devs_lock);
	if (offmap->netdev)
	ret = offmap->dev_ops->map_lookup_elem(offmap, key, value);
	up_read(&bpf_devs_lock);

	return ret;
	}

	int bpf_map_offload_update_elem(struct bpf_map *map,
	void key, void value, u64 flags)
	{
	struct bpf_offloaded_map *offmap = map_to_offmap(map);
	int ret = -ENODEV;

	if (unlikely(flags > BPF_EXIST))
	return -EINVAL;

	down_read(&bpf_devs_lock);
	if (offmap->netdev)
	ret = offmap->dev_ops->map_update_elem(offmap, key, value,
	flags);
	up_read(&bpf_devs_lock);

	return ret;
	}

	int bpf_map_offload_delete_elem(struct bpf_map map, void key)
	{
	struct bpf_offloaded_map *offmap = map_to_offmap(map);
	int ret = -ENODEV;

	down_read(&bpf_devs_lock);
	if (offmap->netdev)
	ret = offmap->dev_ops->map_delete_elem(offmap, key);
	up_read(&bpf_devs_lock);

	return ret;
	}

	int bpf_map_offload_get_next_key(struct bpf_map map, void key, void *next_key)
	{
	struct bpf_offloaded_map *offmap = map_to_offmap(map);
	int ret = -ENODEV;

	down_read(&bpf_devs_lock);
	if (offmap->netdev)
	ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key);
	up_read(&bpf_devs_lock);

	return ret;
	}

	struct ns_get_path_bpf_map_args {
	struct bpf_offloaded_map *offmap;
	struct bpf_map_info *info;
	};

	static struct ns_common bpf_map_offload_info_fill_ns(void private_data)
	{
	struct ns_get_path_bpf_map_args *args = private_data;
	struct ns_common *ns;
	struct net *net;

	rtnl_lock();
	down_read(&bpf_devs_lock);

	if (args->offmap->netdev) {
	args->info->ifindex = args->offmap->netdev->ifindex;
	net = dev_net(args->offmap->netdev);
	get_net(net);
	ns = &net->ns;
	} else {
	args->info->ifindex = 0;
	ns = NULL;
	}

	up_read(&bpf_devs_lock);
	rtnl_unlock();

	return ns;
	}

	int bpf_map_offload_info_fill(struct bpf_map_info info, struct bpf_map map)
	{
	struct ns_get_path_bpf_map_args args = {
	.offmap = map_to_offmap(map),
	.info = info,
	};
	struct inode *ns_inode;
	struct path ns_path;
	int res;

	res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
	if (res) {
	if (!info->ifindex)
	return -ENODEV;
	return res;
	}

	ns_inode = ns_path.dentry->d_inode;
	info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
	info->netns_ino = ns_inode->i_ino;
	path_put(&ns_path);

	return 0;
	}

	static bool __bpf_offload_dev_match(struct bpf_prog *prog,
	struct net_device *netdev)
	{
	struct bpf_offload_netdev ondev1, ondev2;
	struct bpf_prog_offload *offload;

	if (!bpf_prog_is_dev_bound(prog->aux))
	return false;

	offload = prog->aux->offload;
	if (!offload)
	return false;
	if (offload->netdev == netdev)
	return true;

	ondev1 = bpf_offload_find_netdev(offload->netdev);
	ondev2 = bpf_offload_find_netdev(netdev);

	return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev;
	}

	bool bpf_offload_dev_match(struct bpf_prog prog, struct net_device netdev)
	{
	bool ret;

	down_read(&bpf_devs_lock);
	ret = __bpf_offload_dev_match(prog, netdev);
	up_read(&bpf_devs_lock);

	return ret;
	}
	EXPORT_SYMBOL_GPL(bpf_offload_dev_match);

	bool bpf_offload_prog_map_match(struct bpf_prog prog, struct bpf_map map)
	{
	struct bpf_offloaded_map *offmap;
	bool ret;

	if (!bpf_map_is_dev_bound(map))
	return bpf_map_offload_neutral(map);
	offmap = map_to_offmap(map);

	down_read(&bpf_devs_lock);
	ret = __bpf_offload_dev_match(prog, offmap->netdev);
	up_read(&bpf_devs_lock);

	return ret;
	}

	int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
	struct net_device *netdev)
	{
	struct bpf_offload_netdev *ondev;
	int err;

	ondev = kzalloc(sizeof(*ondev), GFP_KERNEL);
	if (!ondev)
	return -ENOMEM;

	ondev->netdev = netdev;
	ondev->offdev = offdev;
	INIT_LIST_HEAD(&ondev->progs);
	INIT_LIST_HEAD(&ondev->maps);

	down_write(&bpf_devs_lock);
	err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params);
	if (err) {
	netdev_warn(netdev, "failed to register for BPF offload\n");
	goto err_unlock_free;
	}

	list_add(&ondev->offdev_netdevs, &offdev->netdevs);
	up_write(&bpf_devs_lock);
	return 0;

	err_unlock_free:
	up_write(&bpf_devs_lock);
	kfree(ondev);
	return err;
	}
	EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register);

	void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
	struct net_device *netdev)
	{
	struct bpf_offload_netdev ondev, altdev;
	struct bpf_offloaded_map offmap, mtmp;
	struct bpf_prog_offload offload, ptmp;

	ASSERT_RTNL();

	down_write(&bpf_devs_lock);
	ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
	if (WARN_ON(!ondev))
	goto unlock;

	WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params));
	list_del(&ondev->offdev_netdevs);

	/* Try to move the objects to another netdev of the device */
	altdev = list_first_entry_or_null(&offdev->netdevs,
	struct bpf_offload_netdev,
	offdev_netdevs);
	if (altdev) {
	list_for_each_entry(offload, &ondev->progs, offloads)
	offload->netdev = altdev->netdev;
	list_splice_init(&ondev->progs, &altdev->progs);

	list_for_each_entry(offmap, &ondev->maps, offloads)
	offmap->netdev = altdev->netdev;
	list_splice_init(&ondev->maps, &altdev->maps);
	} else {
	list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads)
	__bpf_prog_offload_destroy(offload->prog);
	list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads)
	__bpf_map_offload_destroy(offmap);
	}

	WARN_ON(!list_empty(&ondev->progs));
	WARN_ON(!list_empty(&ondev->maps));
	kfree(ondev);
	unlock:
	up_write(&bpf_devs_lock);
	}
	EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister);

	struct bpf_offload_dev *
	bpf_offload_dev_create(const struct bpf_prog_offload_ops ops, void priv)
	{
	struct bpf_offload_dev *offdev;
	int err;

	down_write(&bpf_devs_lock);
	if (!offdevs_inited) {
	err = rhashtable_init(&offdevs, &offdevs_params);
	if (err) {
	up_write(&bpf_devs_lock);
	return ERR_PTR(err);
	}
	offdevs_inited = true;
	}
	up_write(&bpf_devs_lock);

	offdev = kzalloc(sizeof(*offdev), GFP_KERNEL);
	if (!offdev)
	return ERR_PTR(-ENOMEM);

	offdev->ops = ops;
	offdev->priv = priv;
	INIT_LIST_HEAD(&offdev->netdevs);

	return offdev;
	}
	EXPORT_SYMBOL_GPL(bpf_offload_dev_create);

	void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev)
	{
	WARN_ON(!list_empty(&offdev->netdevs));
	kfree(offdev);
	}
	EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy);

	void bpf_offload_dev_priv(struct bpf_offload_dev offdev)
	{
	return offdev->priv;
	}
	EXPORT_SYMBOL_GPL(bpf_offload_dev_priv);