xref: /linux/kernel/bpf/offload.c (revision 0ea5c948cb64bab5bc7a5516774eb8536f05aa0d)
1 /*
2  * Copyright (C) 2017-2018 Netronome Systems, Inc.
3  *
4  * This software is licensed under the GNU General License Version 2,
5  * June 1991 as shown in the file COPYING in the top-level directory of this
6  * source tree.
7  *
8  * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
9  * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
10  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
11  * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
12  * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
13  * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
14  */
15 
16 #include <linux/bpf.h>
17 #include <linux/bpf_verifier.h>
18 #include <linux/bug.h>
19 #include <linux/kdev_t.h>
20 #include <linux/list.h>
21 #include <linux/lockdep.h>
22 #include <linux/netdevice.h>
23 #include <linux/printk.h>
24 #include <linux/proc_ns.h>
25 #include <linux/rhashtable.h>
26 #include <linux/rtnetlink.h>
27 #include <linux/rwsem.h>
28 #include <net/xdp.h>
29 
30 /* Protects offdevs, members of bpf_offload_netdev and offload members
31  * of all progs.
32  * RTNL lock cannot be taken when holding this lock.
33  */
34 static DECLARE_RWSEM(bpf_devs_lock);
35 
36 struct bpf_offload_dev {
37 	const struct bpf_prog_offload_ops *ops;
38 	struct list_head netdevs;
39 	void *priv;
40 };
41 
42 struct bpf_offload_netdev {
43 	struct rhash_head l;
44 	struct net_device *netdev;
45 	struct bpf_offload_dev *offdev; /* NULL when bound-only */
46 	struct list_head progs;
47 	struct list_head maps;
48 	struct list_head offdev_netdevs;
49 };
50 
51 static const struct rhashtable_params offdevs_params = {
52 	.nelem_hint		= 4,
53 	.key_len		= sizeof(struct net_device *),
54 	.key_offset		= offsetof(struct bpf_offload_netdev, netdev),
55 	.head_offset		= offsetof(struct bpf_offload_netdev, l),
56 	.automatic_shrinking	= true,
57 };
58 
59 static struct rhashtable offdevs;
60 
bpf_dev_offload_check(struct net_device * netdev)61 static int bpf_dev_offload_check(struct net_device *netdev)
62 {
63 	if (!netdev)
64 		return -EINVAL;
65 	if (!netdev->netdev_ops->ndo_bpf)
66 		return -EOPNOTSUPP;
67 	return 0;
68 }
69 
70 static struct bpf_offload_netdev *
bpf_offload_find_netdev(struct net_device * netdev)71 bpf_offload_find_netdev(struct net_device *netdev)
72 {
73 	lockdep_assert_held(&bpf_devs_lock);
74 
75 	return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
76 }
77 
__bpf_offload_dev_netdev_register(struct bpf_offload_dev * offdev,struct net_device * netdev)78 static int __bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
79 					     struct net_device *netdev)
80 {
81 	struct bpf_offload_netdev *ondev;
82 	int err;
83 
84 	ondev = kzalloc(sizeof(*ondev), GFP_KERNEL);
85 	if (!ondev)
86 		return -ENOMEM;
87 
88 	ondev->netdev = netdev;
89 	ondev->offdev = offdev;
90 	INIT_LIST_HEAD(&ondev->progs);
91 	INIT_LIST_HEAD(&ondev->maps);
92 
93 	err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params);
94 	if (err) {
95 		netdev_warn(netdev, "failed to register for BPF offload\n");
96 		goto err_free;
97 	}
98 
99 	if (offdev)
100 		list_add(&ondev->offdev_netdevs, &offdev->netdevs);
101 	return 0;
102 
103 err_free:
104 	kfree(ondev);
105 	return err;
106 }
107 
__bpf_prog_offload_destroy(struct bpf_prog * prog)108 static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
109 {
110 	struct bpf_prog_offload *offload = prog->aux->offload;
111 
112 	if (offload->dev_state)
113 		offload->offdev->ops->destroy(prog);
114 
115 	list_del_init(&offload->offloads);
116 	kfree(offload);
117 	prog->aux->offload = NULL;
118 }
119 
bpf_map_offload_ndo(struct bpf_offloaded_map * offmap,enum bpf_netdev_command cmd)120 static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap,
121 			       enum bpf_netdev_command cmd)
122 {
123 	struct netdev_bpf data = {};
124 	struct net_device *netdev;
125 
126 	ASSERT_RTNL();
127 
128 	data.command = cmd;
129 	data.offmap = offmap;
130 	/* Caller must make sure netdev is valid */
131 	netdev = offmap->netdev;
132 
133 	return netdev->netdev_ops->ndo_bpf(netdev, &data);
134 }
135 
__bpf_map_offload_destroy(struct bpf_offloaded_map * offmap)136 static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap)
137 {
138 	WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE));
139 	/* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */
140 	bpf_map_free_id(&offmap->map);
141 	list_del_init(&offmap->offloads);
142 	offmap->netdev = NULL;
143 }
144 
__bpf_offload_dev_netdev_unregister(struct bpf_offload_dev * offdev,struct net_device * netdev)145 static void __bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
146 						struct net_device *netdev)
147 {
148 	struct bpf_offload_netdev *ondev, *altdev = NULL;
149 	struct bpf_offloaded_map *offmap, *mtmp;
150 	struct bpf_prog_offload *offload, *ptmp;
151 
152 	ASSERT_RTNL();
153 
154 	ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
155 	if (WARN_ON(!ondev))
156 		return;
157 
158 	WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params));
159 
160 	/* Try to move the objects to another netdev of the device */
161 	if (offdev) {
162 		list_del(&ondev->offdev_netdevs);
163 		altdev = list_first_entry_or_null(&offdev->netdevs,
164 						  struct bpf_offload_netdev,
165 						  offdev_netdevs);
166 	}
167 
168 	if (altdev) {
169 		list_for_each_entry(offload, &ondev->progs, offloads)
170 			offload->netdev = altdev->netdev;
171 		list_splice_init(&ondev->progs, &altdev->progs);
172 
173 		list_for_each_entry(offmap, &ondev->maps, offloads)
174 			offmap->netdev = altdev->netdev;
175 		list_splice_init(&ondev->maps, &altdev->maps);
176 	} else {
177 		list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads)
178 			__bpf_prog_offload_destroy(offload->prog);
179 		list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads)
180 			__bpf_map_offload_destroy(offmap);
181 	}
182 
183 	WARN_ON(!list_empty(&ondev->progs));
184 	WARN_ON(!list_empty(&ondev->maps));
185 	kfree(ondev);
186 }
187 
__bpf_prog_dev_bound_init(struct bpf_prog * prog,struct net_device * netdev)188 static int __bpf_prog_dev_bound_init(struct bpf_prog *prog, struct net_device *netdev)
189 {
190 	struct bpf_offload_netdev *ondev;
191 	struct bpf_prog_offload *offload;
192 	int err;
193 
194 	offload = kzalloc(sizeof(*offload), GFP_USER);
195 	if (!offload)
196 		return -ENOMEM;
197 
198 	offload->prog = prog;
199 	offload->netdev = netdev;
200 
201 	ondev = bpf_offload_find_netdev(offload->netdev);
202 	/* When program is offloaded require presence of "true"
203 	 * bpf_offload_netdev, avoid the one created for !ondev case below.
204 	 */
205 	if (bpf_prog_is_offloaded(prog->aux) && (!ondev || !ondev->offdev)) {
206 		err = -EINVAL;
207 		goto err_free;
208 	}
209 	if (!ondev) {
210 		/* When only binding to the device, explicitly
211 		 * create an entry in the hashtable.
212 		 */
213 		err = __bpf_offload_dev_netdev_register(NULL, offload->netdev);
214 		if (err)
215 			goto err_free;
216 		ondev = bpf_offload_find_netdev(offload->netdev);
217 	}
218 	offload->offdev = ondev->offdev;
219 	prog->aux->offload = offload;
220 	list_add_tail(&offload->offloads, &ondev->progs);
221 
222 	return 0;
223 err_free:
224 	kfree(offload);
225 	return err;
226 }
227 
bpf_prog_dev_bound_init(struct bpf_prog * prog,union bpf_attr * attr)228 int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
229 {
230 	struct net_device *netdev;
231 	int err;
232 
233 	if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS &&
234 	    attr->prog_type != BPF_PROG_TYPE_XDP)
235 		return -EINVAL;
236 
237 	if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
238 		return -EINVAL;
239 
240 	/* Frags are allowed only if program is dev-bound-only, but not
241 	 * if it is requesting bpf offload.
242 	 */
243 	if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS &&
244 	    !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY))
245 		return -EINVAL;
246 
247 	if (attr->prog_type == BPF_PROG_TYPE_SCHED_CLS &&
248 	    attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY)
249 		return -EINVAL;
250 
251 	netdev = dev_get_by_index(current->nsproxy->net_ns, attr->prog_ifindex);
252 	if (!netdev)
253 		return -EINVAL;
254 
255 	err = bpf_dev_offload_check(netdev);
256 	if (err)
257 		goto out;
258 
259 	prog->aux->offload_requested = !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY);
260 
261 	down_write(&bpf_devs_lock);
262 	err = __bpf_prog_dev_bound_init(prog, netdev);
263 	up_write(&bpf_devs_lock);
264 
265 out:
266 	dev_put(netdev);
267 	return err;
268 }
269 
bpf_prog_dev_bound_inherit(struct bpf_prog * new_prog,struct bpf_prog * old_prog)270 int bpf_prog_dev_bound_inherit(struct bpf_prog *new_prog, struct bpf_prog *old_prog)
271 {
272 	int err;
273 
274 	if (!bpf_prog_is_dev_bound(old_prog->aux))
275 		return 0;
276 
277 	if (bpf_prog_is_offloaded(old_prog->aux))
278 		return -EINVAL;
279 
280 	new_prog->aux->dev_bound = old_prog->aux->dev_bound;
281 	new_prog->aux->offload_requested = old_prog->aux->offload_requested;
282 
283 	down_write(&bpf_devs_lock);
284 	if (!old_prog->aux->offload) {
285 		err = -EINVAL;
286 		goto out;
287 	}
288 
289 	err = __bpf_prog_dev_bound_init(new_prog, old_prog->aux->offload->netdev);
290 
291 out:
292 	up_write(&bpf_devs_lock);
293 	return err;
294 }
295 
bpf_prog_offload_verifier_prep(struct bpf_prog * prog)296 int bpf_prog_offload_verifier_prep(struct bpf_prog *prog)
297 {
298 	struct bpf_prog_offload *offload;
299 	int ret = -ENODEV;
300 
301 	down_read(&bpf_devs_lock);
302 	offload = prog->aux->offload;
303 	if (offload) {
304 		ret = offload->offdev->ops->prepare(prog);
305 		offload->dev_state = !ret;
306 	}
307 	up_read(&bpf_devs_lock);
308 
309 	return ret;
310 }
311 
bpf_prog_offload_verify_insn(struct bpf_verifier_env * env,int insn_idx,int prev_insn_idx)312 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
313 				 int insn_idx, int prev_insn_idx)
314 {
315 	struct bpf_prog_offload *offload;
316 	int ret = -ENODEV;
317 
318 	down_read(&bpf_devs_lock);
319 	offload = env->prog->aux->offload;
320 	if (offload)
321 		ret = offload->offdev->ops->insn_hook(env, insn_idx,
322 						      prev_insn_idx);
323 	up_read(&bpf_devs_lock);
324 
325 	return ret;
326 }
327 
bpf_prog_offload_finalize(struct bpf_verifier_env * env)328 int bpf_prog_offload_finalize(struct bpf_verifier_env *env)
329 {
330 	struct bpf_prog_offload *offload;
331 	int ret = -ENODEV;
332 
333 	down_read(&bpf_devs_lock);
334 	offload = env->prog->aux->offload;
335 	if (offload) {
336 		if (offload->offdev->ops->finalize)
337 			ret = offload->offdev->ops->finalize(env);
338 		else
339 			ret = 0;
340 	}
341 	up_read(&bpf_devs_lock);
342 
343 	return ret;
344 }
345 
346 void
bpf_prog_offload_replace_insn(struct bpf_verifier_env * env,u32 off,struct bpf_insn * insn)347 bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
348 			      struct bpf_insn *insn)
349 {
350 	const struct bpf_prog_offload_ops *ops;
351 	struct bpf_prog_offload *offload;
352 	int ret = -EOPNOTSUPP;
353 
354 	down_read(&bpf_devs_lock);
355 	offload = env->prog->aux->offload;
356 	if (offload) {
357 		ops = offload->offdev->ops;
358 		if (!offload->opt_failed && ops->replace_insn)
359 			ret = ops->replace_insn(env, off, insn);
360 		offload->opt_failed |= ret;
361 	}
362 	up_read(&bpf_devs_lock);
363 }
364 
365 void
bpf_prog_offload_remove_insns(struct bpf_verifier_env * env,u32 off,u32 cnt)366 bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
367 {
368 	struct bpf_prog_offload *offload;
369 	int ret = -EOPNOTSUPP;
370 
371 	down_read(&bpf_devs_lock);
372 	offload = env->prog->aux->offload;
373 	if (offload) {
374 		if (!offload->opt_failed && offload->offdev->ops->remove_insns)
375 			ret = offload->offdev->ops->remove_insns(env, off, cnt);
376 		offload->opt_failed |= ret;
377 	}
378 	up_read(&bpf_devs_lock);
379 }
380 
bpf_prog_dev_bound_destroy(struct bpf_prog * prog)381 void bpf_prog_dev_bound_destroy(struct bpf_prog *prog)
382 {
383 	struct bpf_offload_netdev *ondev;
384 	struct net_device *netdev;
385 
386 	rtnl_lock();
387 	down_write(&bpf_devs_lock);
388 	if (prog->aux->offload) {
389 		list_del_init(&prog->aux->offload->offloads);
390 
391 		netdev = prog->aux->offload->netdev;
392 		__bpf_prog_offload_destroy(prog);
393 
394 		ondev = bpf_offload_find_netdev(netdev);
395 		if (!ondev->offdev && list_empty(&ondev->progs))
396 			__bpf_offload_dev_netdev_unregister(NULL, netdev);
397 	}
398 	up_write(&bpf_devs_lock);
399 	rtnl_unlock();
400 }
401 
bpf_prog_offload_translate(struct bpf_prog * prog)402 static int bpf_prog_offload_translate(struct bpf_prog *prog)
403 {
404 	struct bpf_prog_offload *offload;
405 	int ret = -ENODEV;
406 
407 	down_read(&bpf_devs_lock);
408 	offload = prog->aux->offload;
409 	if (offload)
410 		ret = offload->offdev->ops->translate(prog);
411 	up_read(&bpf_devs_lock);
412 
413 	return ret;
414 }
415 
bpf_prog_warn_on_exec(const void * ctx,const struct bpf_insn * insn)416 static unsigned int bpf_prog_warn_on_exec(const void *ctx,
417 					  const struct bpf_insn *insn)
418 {
419 	WARN(1, "attempt to execute device eBPF program on the host!");
420 	return 0;
421 }
422 
bpf_prog_offload_compile(struct bpf_prog * prog)423 int bpf_prog_offload_compile(struct bpf_prog *prog)
424 {
425 	prog->bpf_func = bpf_prog_warn_on_exec;
426 
427 	return bpf_prog_offload_translate(prog);
428 }
429 
430 struct ns_get_path_bpf_prog_args {
431 	struct bpf_prog *prog;
432 	struct bpf_prog_info *info;
433 };
434 
bpf_prog_offload_info_fill_ns(void * private_data)435 static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data)
436 {
437 	struct ns_get_path_bpf_prog_args *args = private_data;
438 	struct bpf_prog_aux *aux = args->prog->aux;
439 	struct ns_common *ns;
440 	struct net *net;
441 
442 	rtnl_lock();
443 	down_read(&bpf_devs_lock);
444 
445 	if (aux->offload) {
446 		args->info->ifindex = aux->offload->netdev->ifindex;
447 		net = dev_net(aux->offload->netdev);
448 		get_net(net);
449 		ns = &net->ns;
450 	} else {
451 		args->info->ifindex = 0;
452 		ns = NULL;
453 	}
454 
455 	up_read(&bpf_devs_lock);
456 	rtnl_unlock();
457 
458 	return ns;
459 }
460 
bpf_prog_offload_info_fill(struct bpf_prog_info * info,struct bpf_prog * prog)461 int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
462 			       struct bpf_prog *prog)
463 {
464 	struct ns_get_path_bpf_prog_args args = {
465 		.prog	= prog,
466 		.info	= info,
467 	};
468 	struct bpf_prog_aux *aux = prog->aux;
469 	struct inode *ns_inode;
470 	struct path ns_path;
471 	char __user *uinsns;
472 	int res;
473 	u32 ulen;
474 
475 	res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
476 	if (res) {
477 		if (!info->ifindex)
478 			return -ENODEV;
479 		return res;
480 	}
481 
482 	down_read(&bpf_devs_lock);
483 
484 	if (!aux->offload) {
485 		up_read(&bpf_devs_lock);
486 		return -ENODEV;
487 	}
488 
489 	ulen = info->jited_prog_len;
490 	info->jited_prog_len = aux->offload->jited_len;
491 	if (info->jited_prog_len && ulen) {
492 		uinsns = u64_to_user_ptr(info->jited_prog_insns);
493 		ulen = min_t(u32, info->jited_prog_len, ulen);
494 		if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {
495 			up_read(&bpf_devs_lock);
496 			return -EFAULT;
497 		}
498 	}
499 
500 	up_read(&bpf_devs_lock);
501 
502 	ns_inode = ns_path.dentry->d_inode;
503 	info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
504 	info->netns_ino = ns_inode->i_ino;
505 	path_put(&ns_path);
506 
507 	return 0;
508 }
509 
510 const struct bpf_prog_ops bpf_offload_prog_ops = {
511 };
512 
bpf_map_offload_map_alloc(union bpf_attr * attr)513 struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr)
514 {
515 	struct net *net = current->nsproxy->net_ns;
516 	struct bpf_offload_netdev *ondev;
517 	struct bpf_offloaded_map *offmap;
518 	int err;
519 
520 	if (!capable(CAP_SYS_ADMIN))
521 		return ERR_PTR(-EPERM);
522 	if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
523 	    attr->map_type != BPF_MAP_TYPE_HASH)
524 		return ERR_PTR(-EINVAL);
525 
526 	offmap = bpf_map_area_alloc(sizeof(*offmap), NUMA_NO_NODE);
527 	if (!offmap)
528 		return ERR_PTR(-ENOMEM);
529 
530 	bpf_map_init_from_attr(&offmap->map, attr);
531 
532 	rtnl_lock();
533 	down_write(&bpf_devs_lock);
534 	offmap->netdev = __dev_get_by_index(net, attr->map_ifindex);
535 	err = bpf_dev_offload_check(offmap->netdev);
536 	if (err)
537 		goto err_unlock;
538 
539 	ondev = bpf_offload_find_netdev(offmap->netdev);
540 	if (!ondev) {
541 		err = -EINVAL;
542 		goto err_unlock;
543 	}
544 
545 	err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC);
546 	if (err)
547 		goto err_unlock;
548 
549 	list_add_tail(&offmap->offloads, &ondev->maps);
550 	up_write(&bpf_devs_lock);
551 	rtnl_unlock();
552 
553 	return &offmap->map;
554 
555 err_unlock:
556 	up_write(&bpf_devs_lock);
557 	rtnl_unlock();
558 	bpf_map_area_free(offmap);
559 	return ERR_PTR(err);
560 }
561 
bpf_map_offload_map_free(struct bpf_map * map)562 void bpf_map_offload_map_free(struct bpf_map *map)
563 {
564 	struct bpf_offloaded_map *offmap = map_to_offmap(map);
565 
566 	rtnl_lock();
567 	down_write(&bpf_devs_lock);
568 	if (offmap->netdev)
569 		__bpf_map_offload_destroy(offmap);
570 	up_write(&bpf_devs_lock);
571 	rtnl_unlock();
572 
573 	bpf_map_area_free(offmap);
574 }
575 
bpf_map_offload_map_mem_usage(const struct bpf_map * map)576 u64 bpf_map_offload_map_mem_usage(const struct bpf_map *map)
577 {
578 	/* The memory dynamically allocated in netdev dev_ops is not counted */
579 	return sizeof(struct bpf_offloaded_map);
580 }
581 
bpf_map_offload_lookup_elem(struct bpf_map * map,void * key,void * value)582 int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value)
583 {
584 	struct bpf_offloaded_map *offmap = map_to_offmap(map);
585 	int ret = -ENODEV;
586 
587 	down_read(&bpf_devs_lock);
588 	if (offmap->netdev)
589 		ret = offmap->dev_ops->map_lookup_elem(offmap, key, value);
590 	up_read(&bpf_devs_lock);
591 
592 	return ret;
593 }
594 
bpf_map_offload_update_elem(struct bpf_map * map,void * key,void * value,u64 flags)595 int bpf_map_offload_update_elem(struct bpf_map *map,
596 				void *key, void *value, u64 flags)
597 {
598 	struct bpf_offloaded_map *offmap = map_to_offmap(map);
599 	int ret = -ENODEV;
600 
601 	if (unlikely(flags > BPF_EXIST))
602 		return -EINVAL;
603 
604 	down_read(&bpf_devs_lock);
605 	if (offmap->netdev)
606 		ret = offmap->dev_ops->map_update_elem(offmap, key, value,
607 						       flags);
608 	up_read(&bpf_devs_lock);
609 
610 	return ret;
611 }
612 
bpf_map_offload_delete_elem(struct bpf_map * map,void * key)613 int bpf_map_offload_delete_elem(struct bpf_map *map, void *key)
614 {
615 	struct bpf_offloaded_map *offmap = map_to_offmap(map);
616 	int ret = -ENODEV;
617 
618 	down_read(&bpf_devs_lock);
619 	if (offmap->netdev)
620 		ret = offmap->dev_ops->map_delete_elem(offmap, key);
621 	up_read(&bpf_devs_lock);
622 
623 	return ret;
624 }
625 
bpf_map_offload_get_next_key(struct bpf_map * map,void * key,void * next_key)626 int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key)
627 {
628 	struct bpf_offloaded_map *offmap = map_to_offmap(map);
629 	int ret = -ENODEV;
630 
631 	down_read(&bpf_devs_lock);
632 	if (offmap->netdev)
633 		ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key);
634 	up_read(&bpf_devs_lock);
635 
636 	return ret;
637 }
638 
639 struct ns_get_path_bpf_map_args {
640 	struct bpf_offloaded_map *offmap;
641 	struct bpf_map_info *info;
642 };
643 
bpf_map_offload_info_fill_ns(void * private_data)644 static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data)
645 {
646 	struct ns_get_path_bpf_map_args *args = private_data;
647 	struct ns_common *ns;
648 	struct net *net;
649 
650 	rtnl_lock();
651 	down_read(&bpf_devs_lock);
652 
653 	if (args->offmap->netdev) {
654 		args->info->ifindex = args->offmap->netdev->ifindex;
655 		net = dev_net(args->offmap->netdev);
656 		get_net(net);
657 		ns = &net->ns;
658 	} else {
659 		args->info->ifindex = 0;
660 		ns = NULL;
661 	}
662 
663 	up_read(&bpf_devs_lock);
664 	rtnl_unlock();
665 
666 	return ns;
667 }
668 
bpf_map_offload_info_fill(struct bpf_map_info * info,struct bpf_map * map)669 int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map)
670 {
671 	struct ns_get_path_bpf_map_args args = {
672 		.offmap	= map_to_offmap(map),
673 		.info	= info,
674 	};
675 	struct inode *ns_inode;
676 	struct path ns_path;
677 	int res;
678 
679 	res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
680 	if (res) {
681 		if (!info->ifindex)
682 			return -ENODEV;
683 		return res;
684 	}
685 
686 	ns_inode = ns_path.dentry->d_inode;
687 	info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
688 	info->netns_ino = ns_inode->i_ino;
689 	path_put(&ns_path);
690 
691 	return 0;
692 }
693 
__bpf_offload_dev_match(struct bpf_prog * prog,struct net_device * netdev)694 static bool __bpf_offload_dev_match(struct bpf_prog *prog,
695 				    struct net_device *netdev)
696 {
697 	struct bpf_offload_netdev *ondev1, *ondev2;
698 	struct bpf_prog_offload *offload;
699 
700 	if (!bpf_prog_is_dev_bound(prog->aux))
701 		return false;
702 
703 	offload = prog->aux->offload;
704 	if (!offload)
705 		return false;
706 	if (offload->netdev == netdev)
707 		return true;
708 
709 	ondev1 = bpf_offload_find_netdev(offload->netdev);
710 	ondev2 = bpf_offload_find_netdev(netdev);
711 
712 	return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev;
713 }
714 
bpf_offload_dev_match(struct bpf_prog * prog,struct net_device * netdev)715 bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev)
716 {
717 	bool ret;
718 
719 	down_read(&bpf_devs_lock);
720 	ret = __bpf_offload_dev_match(prog, netdev);
721 	up_read(&bpf_devs_lock);
722 
723 	return ret;
724 }
725 EXPORT_SYMBOL_GPL(bpf_offload_dev_match);
726 
bpf_prog_dev_bound_match(const struct bpf_prog * lhs,const struct bpf_prog * rhs)727 bool bpf_prog_dev_bound_match(const struct bpf_prog *lhs, const struct bpf_prog *rhs)
728 {
729 	bool ret;
730 
731 	if (bpf_prog_is_offloaded(lhs->aux) != bpf_prog_is_offloaded(rhs->aux))
732 		return false;
733 
734 	down_read(&bpf_devs_lock);
735 	ret = lhs->aux->offload && rhs->aux->offload &&
736 	      lhs->aux->offload->netdev &&
737 	      lhs->aux->offload->netdev == rhs->aux->offload->netdev;
738 	up_read(&bpf_devs_lock);
739 
740 	return ret;
741 }
742 
bpf_offload_prog_map_match(struct bpf_prog * prog,struct bpf_map * map)743 bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map)
744 {
745 	struct bpf_offloaded_map *offmap;
746 	bool ret;
747 
748 	if (!bpf_map_is_offloaded(map))
749 		return bpf_map_offload_neutral(map);
750 	offmap = map_to_offmap(map);
751 
752 	down_read(&bpf_devs_lock);
753 	ret = __bpf_offload_dev_match(prog, offmap->netdev);
754 	up_read(&bpf_devs_lock);
755 
756 	return ret;
757 }
758 
bpf_offload_dev_netdev_register(struct bpf_offload_dev * offdev,struct net_device * netdev)759 int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
760 				    struct net_device *netdev)
761 {
762 	int err;
763 
764 	down_write(&bpf_devs_lock);
765 	err = __bpf_offload_dev_netdev_register(offdev, netdev);
766 	up_write(&bpf_devs_lock);
767 	return err;
768 }
769 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register);
770 
bpf_offload_dev_netdev_unregister(struct bpf_offload_dev * offdev,struct net_device * netdev)771 void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
772 				       struct net_device *netdev)
773 {
774 	down_write(&bpf_devs_lock);
775 	__bpf_offload_dev_netdev_unregister(offdev, netdev);
776 	up_write(&bpf_devs_lock);
777 }
778 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister);
779 
780 struct bpf_offload_dev *
bpf_offload_dev_create(const struct bpf_prog_offload_ops * ops,void * priv)781 bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops, void *priv)
782 {
783 	struct bpf_offload_dev *offdev;
784 
785 	offdev = kzalloc(sizeof(*offdev), GFP_KERNEL);
786 	if (!offdev)
787 		return ERR_PTR(-ENOMEM);
788 
789 	offdev->ops = ops;
790 	offdev->priv = priv;
791 	INIT_LIST_HEAD(&offdev->netdevs);
792 
793 	return offdev;
794 }
795 EXPORT_SYMBOL_GPL(bpf_offload_dev_create);
796 
bpf_offload_dev_destroy(struct bpf_offload_dev * offdev)797 void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev)
798 {
799 	WARN_ON(!list_empty(&offdev->netdevs));
800 	kfree(offdev);
801 }
802 EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy);
803 
bpf_offload_dev_priv(struct bpf_offload_dev * offdev)804 void *bpf_offload_dev_priv(struct bpf_offload_dev *offdev)
805 {
806 	return offdev->priv;
807 }
808 EXPORT_SYMBOL_GPL(bpf_offload_dev_priv);
809 
bpf_dev_bound_netdev_unregister(struct net_device * dev)810 void bpf_dev_bound_netdev_unregister(struct net_device *dev)
811 {
812 	struct bpf_offload_netdev *ondev;
813 
814 	ASSERT_RTNL();
815 
816 	down_write(&bpf_devs_lock);
817 	ondev = bpf_offload_find_netdev(dev);
818 	if (ondev && !ondev->offdev)
819 		__bpf_offload_dev_netdev_unregister(NULL, ondev->netdev);
820 	up_write(&bpf_devs_lock);
821 }
822 
bpf_dev_bound_kfunc_check(struct bpf_verifier_log * log,struct bpf_prog_aux * prog_aux)823 int bpf_dev_bound_kfunc_check(struct bpf_verifier_log *log,
824 			      struct bpf_prog_aux *prog_aux)
825 {
826 	if (!bpf_prog_is_dev_bound(prog_aux)) {
827 		bpf_log(log, "metadata kfuncs require device-bound program\n");
828 		return -EINVAL;
829 	}
830 
831 	if (bpf_prog_is_offloaded(prog_aux)) {
832 		bpf_log(log, "metadata kfuncs can't be offloaded\n");
833 		return -EINVAL;
834 	}
835 
836 	return 0;
837 }
838 
bpf_dev_bound_resolve_kfunc(struct bpf_prog * prog,u32 func_id)839 void *bpf_dev_bound_resolve_kfunc(struct bpf_prog *prog, u32 func_id)
840 {
841 	const struct xdp_metadata_ops *ops;
842 	void *p = NULL;
843 
844 	/* We don't hold bpf_devs_lock while resolving several
845 	 * kfuncs and can race with the unregister_netdevice().
846 	 * We rely on bpf_dev_bound_match() check at attach
847 	 * to render this program unusable.
848 	 */
849 	down_read(&bpf_devs_lock);
850 	if (!prog->aux->offload)
851 		goto out;
852 
853 	ops = prog->aux->offload->netdev->xdp_metadata_ops;
854 	if (!ops)
855 		goto out;
856 
857 #define XDP_METADATA_KFUNC(name, _, __, xmo) \
858 	if (func_id == bpf_xdp_metadata_kfunc_id(name)) p = ops->xmo;
859 	XDP_METADATA_KFUNC_xxx
860 #undef XDP_METADATA_KFUNC
861 
862 out:
863 	up_read(&bpf_devs_lock);
864 
865 	return p;
866 }
867 
bpf_offload_init(void)868 static int __init bpf_offload_init(void)
869 {
870 	return rhashtable_init(&offdevs, &offdevs_params);
871 }
872 
873 core_initcall(bpf_offload_init);
874