projects/linux·blob v5.0 · refs

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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
29/* Protects offdevs, members of bpf_offload_netdev and offload members
30 * of all progs.
31 * RTNL lock cannot be taken when holding this lock.
32 */
33static DECLARE_RWSEM(bpf_devs_lock);
34
35struct bpf_offload_dev {
36 const struct bpf_prog_offload_ops *ops;
37 struct list_head netdevs;
38};
39
40struct bpf_offload_netdev {
41 struct rhash_head l;
42 struct net_device *netdev;
43 struct bpf_offload_dev *offdev;
44 struct list_head progs;
45 struct list_head maps;
46 struct list_head offdev_netdevs;
47};
48
49static const struct rhashtable_params offdevs_params = {
50 .nelem_hint = 4,
51 .key_len = sizeof(struct net_device *),
52 .key_offset = offsetof(struct bpf_offload_netdev, netdev),
53 .head_offset = offsetof(struct bpf_offload_netdev, l),
54 .automatic_shrinking = true,
55};
56
57static struct rhashtable offdevs;
58static bool offdevs_inited;
59
60static int bpf_dev_offload_check(struct net_device *netdev)
61{
62 if (!netdev)
63 return -EINVAL;
64 if (!netdev->netdev_ops->ndo_bpf)
65 return -EOPNOTSUPP;
66 return 0;
67}
68
69static struct bpf_offload_netdev *
70bpf_offload_find_netdev(struct net_device *netdev)
71{
72 lockdep_assert_held(&bpf_devs_lock);
73
74 if (!offdevs_inited)
75 return NULL;
76 return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
77}
78
79int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
80{
81 struct bpf_offload_netdev *ondev;
82 struct bpf_prog_offload *offload;
83 int err;
84
85 if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS &&
86 attr->prog_type != BPF_PROG_TYPE_XDP)
87 return -EINVAL;
88
89 if (attr->prog_flags)
90 return -EINVAL;
91
92 offload = kzalloc(sizeof(*offload), GFP_USER);
93 if (!offload)
94 return -ENOMEM;
95
96 offload->prog = prog;
97
98 offload->netdev = dev_get_by_index(current->nsproxy->net_ns,
99 attr->prog_ifindex);
100 err = bpf_dev_offload_check(offload->netdev);
101 if (err)
102 goto err_maybe_put;
103
104 down_write(&bpf_devs_lock);
105 ondev = bpf_offload_find_netdev(offload->netdev);
106 if (!ondev) {
107 err = -EINVAL;
108 goto err_unlock;
109 }
110 offload->offdev = ondev->offdev;
111 prog->aux->offload = offload;
112 list_add_tail(&offload->offloads, &ondev->progs);
113 dev_put(offload->netdev);
114 up_write(&bpf_devs_lock);
115
116 return 0;
117err_unlock:
118 up_write(&bpf_devs_lock);
119err_maybe_put:
120 if (offload->netdev)
121 dev_put(offload->netdev);
122 kfree(offload);
123 return err;
124}
125
126int bpf_prog_offload_verifier_prep(struct bpf_prog *prog)
127{
128 struct bpf_prog_offload *offload;
129 int ret = -ENODEV;
130
131 down_read(&bpf_devs_lock);
132 offload = prog->aux->offload;
133 if (offload) {
134 ret = offload->offdev->ops->prepare(prog);
135 offload->dev_state = !ret;
136 }
137 up_read(&bpf_devs_lock);
138
139 return ret;
140}
141
142int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
143 int insn_idx, int prev_insn_idx)
144{
145 struct bpf_prog_offload *offload;
146 int ret = -ENODEV;
147
148 down_read(&bpf_devs_lock);
149 offload = env->prog->aux->offload;
150 if (offload)
151 ret = offload->offdev->ops->insn_hook(env, insn_idx,
152 prev_insn_idx);
153 up_read(&bpf_devs_lock);
154
155 return ret;
156}
157
158int bpf_prog_offload_finalize(struct bpf_verifier_env *env)
159{
160 struct bpf_prog_offload *offload;
161 int ret = -ENODEV;
162
163 down_read(&bpf_devs_lock);
164 offload = env->prog->aux->offload;
165 if (offload) {
166 if (offload->offdev->ops->finalize)
167 ret = offload->offdev->ops->finalize(env);
168 else
169 ret = 0;
170 }
171 up_read(&bpf_devs_lock);
172
173 return ret;
174}
175
176static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
177{
178 struct bpf_prog_offload *offload = prog->aux->offload;
179
180 if (offload->dev_state)
181 offload->offdev->ops->destroy(prog);
182
183 /* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */
184 bpf_prog_free_id(prog, true);
185
186 list_del_init(&offload->offloads);
187 kfree(offload);
188 prog->aux->offload = NULL;
189}
190
191void bpf_prog_offload_destroy(struct bpf_prog *prog)
192{
193 down_write(&bpf_devs_lock);
194 if (prog->aux->offload)
195 __bpf_prog_offload_destroy(prog);
196 up_write(&bpf_devs_lock);
197}
198
199static int bpf_prog_offload_translate(struct bpf_prog *prog)
200{
201 struct bpf_prog_offload *offload;
202 int ret = -ENODEV;
203
204 down_read(&bpf_devs_lock);
205 offload = prog->aux->offload;
206 if (offload)
207 ret = offload->offdev->ops->translate(prog);
208 up_read(&bpf_devs_lock);
209
210 return ret;
211}
212
213static unsigned int bpf_prog_warn_on_exec(const void *ctx,
214 const struct bpf_insn *insn)
215{
216 WARN(1, "attempt to execute device eBPF program on the host!");
217 return 0;
218}
219
220int bpf_prog_offload_compile(struct bpf_prog *prog)
221{
222 prog->bpf_func = bpf_prog_warn_on_exec;
223
224 return bpf_prog_offload_translate(prog);
225}
226
227struct ns_get_path_bpf_prog_args {
228 struct bpf_prog *prog;
229 struct bpf_prog_info *info;
230};
231
232static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data)
233{
234 struct ns_get_path_bpf_prog_args *args = private_data;
235 struct bpf_prog_aux *aux = args->prog->aux;
236 struct ns_common *ns;
237 struct net *net;
238
239 rtnl_lock();
240 down_read(&bpf_devs_lock);
241
242 if (aux->offload) {
243 args->info->ifindex = aux->offload->netdev->ifindex;
244 net = dev_net(aux->offload->netdev);
245 get_net(net);
246 ns = &net->ns;
247 } else {
248 args->info->ifindex = 0;
249 ns = NULL;
250 }
251
252 up_read(&bpf_devs_lock);
253 rtnl_unlock();
254
255 return ns;
256}
257
258int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
259 struct bpf_prog *prog)
260{
261 struct ns_get_path_bpf_prog_args args = {
262 .prog = prog,
263 .info = info,
264 };
265 struct bpf_prog_aux *aux = prog->aux;
266 struct inode *ns_inode;
267 struct path ns_path;
268 char __user *uinsns;
269 void *res;
270 u32 ulen;
271
272 res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
273 if (IS_ERR(res)) {
274 if (!info->ifindex)
275 return -ENODEV;
276 return PTR_ERR(res);
277 }
278
279 down_read(&bpf_devs_lock);
280
281 if (!aux->offload) {
282 up_read(&bpf_devs_lock);
283 return -ENODEV;
284 }
285
286 ulen = info->jited_prog_len;
287 info->jited_prog_len = aux->offload->jited_len;
288 if (info->jited_prog_len & ulen) {
289 uinsns = u64_to_user_ptr(info->jited_prog_insns);
290 ulen = min_t(u32, info->jited_prog_len, ulen);
291 if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {
292 up_read(&bpf_devs_lock);
293 return -EFAULT;
294 }
295 }
296
297 up_read(&bpf_devs_lock);
298
299 ns_inode = ns_path.dentry->d_inode;
300 info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
301 info->netns_ino = ns_inode->i_ino;
302 path_put(&ns_path);
303
304 return 0;
305}
306
307const struct bpf_prog_ops bpf_offload_prog_ops = {
308};
309
310static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap,
311 enum bpf_netdev_command cmd)
312{
313 struct netdev_bpf data = {};
314 struct net_device *netdev;
315
316 ASSERT_RTNL();
317
318 data.command = cmd;
319 data.offmap = offmap;
320 /* Caller must make sure netdev is valid */
321 netdev = offmap->netdev;
322
323 return netdev->netdev_ops->ndo_bpf(netdev, &data);
324}
325
326struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr)
327{
328 struct net *net = current->nsproxy->net_ns;
329 struct bpf_offload_netdev *ondev;
330 struct bpf_offloaded_map *offmap;
331 int err;
332
333 if (!capable(CAP_SYS_ADMIN))
334 return ERR_PTR(-EPERM);
335 if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
336 attr->map_type != BPF_MAP_TYPE_HASH)
337 return ERR_PTR(-EINVAL);
338
339 offmap = kzalloc(sizeof(*offmap), GFP_USER);
340 if (!offmap)
341 return ERR_PTR(-ENOMEM);
342
343 bpf_map_init_from_attr(&offmap->map, attr);
344
345 rtnl_lock();
346 down_write(&bpf_devs_lock);
347 offmap->netdev = __dev_get_by_index(net, attr->map_ifindex);
348 err = bpf_dev_offload_check(offmap->netdev);
349 if (err)
350 goto err_unlock;
351
352 ondev = bpf_offload_find_netdev(offmap->netdev);
353 if (!ondev) {
354 err = -EINVAL;
355 goto err_unlock;
356 }
357
358 err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC);
359 if (err)
360 goto err_unlock;
361
362 list_add_tail(&offmap->offloads, &ondev->maps);
363 up_write(&bpf_devs_lock);
364 rtnl_unlock();
365
366 return &offmap->map;
367
368err_unlock:
369 up_write(&bpf_devs_lock);
370 rtnl_unlock();
371 kfree(offmap);
372 return ERR_PTR(err);
373}
374
375static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap)
376{
377 WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE));
378 /* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */
379 bpf_map_free_id(&offmap->map, true);
380 list_del_init(&offmap->offloads);
381 offmap->netdev = NULL;
382}
383
384void bpf_map_offload_map_free(struct bpf_map *map)
385{
386 struct bpf_offloaded_map *offmap = map_to_offmap(map);
387
388 rtnl_lock();
389 down_write(&bpf_devs_lock);
390 if (offmap->netdev)
391 __bpf_map_offload_destroy(offmap);
392 up_write(&bpf_devs_lock);
393 rtnl_unlock();
394
395 kfree(offmap);
396}
397
398int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value)
399{
400 struct bpf_offloaded_map *offmap = map_to_offmap(map);
401 int ret = -ENODEV;
402
403 down_read(&bpf_devs_lock);
404 if (offmap->netdev)
405 ret = offmap->dev_ops->map_lookup_elem(offmap, key, value);
406 up_read(&bpf_devs_lock);
407
408 return ret;
409}
410
411int bpf_map_offload_update_elem(struct bpf_map *map,
412 void *key, void *value, u64 flags)
413{
414 struct bpf_offloaded_map *offmap = map_to_offmap(map);
415 int ret = -ENODEV;
416
417 if (unlikely(flags > BPF_EXIST))
418 return -EINVAL;
419
420 down_read(&bpf_devs_lock);
421 if (offmap->netdev)
422 ret = offmap->dev_ops->map_update_elem(offmap, key, value,
423 flags);
424 up_read(&bpf_devs_lock);
425
426 return ret;
427}
428
429int bpf_map_offload_delete_elem(struct bpf_map *map, void *key)
430{
431 struct bpf_offloaded_map *offmap = map_to_offmap(map);
432 int ret = -ENODEV;
433
434 down_read(&bpf_devs_lock);
435 if (offmap->netdev)
436 ret = offmap->dev_ops->map_delete_elem(offmap, key);
437 up_read(&bpf_devs_lock);
438
439 return ret;
440}
441
442int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key)
443{
444 struct bpf_offloaded_map *offmap = map_to_offmap(map);
445 int ret = -ENODEV;
446
447 down_read(&bpf_devs_lock);
448 if (offmap->netdev)
449 ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key);
450 up_read(&bpf_devs_lock);
451
452 return ret;
453}
454
455struct ns_get_path_bpf_map_args {
456 struct bpf_offloaded_map *offmap;
457 struct bpf_map_info *info;
458};
459
460static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data)
461{
462 struct ns_get_path_bpf_map_args *args = private_data;
463 struct ns_common *ns;
464 struct net *net;
465
466 rtnl_lock();
467 down_read(&bpf_devs_lock);
468
469 if (args->offmap->netdev) {
470 args->info->ifindex = args->offmap->netdev->ifindex;
471 net = dev_net(args->offmap->netdev);
472 get_net(net);
473 ns = &net->ns;
474 } else {
475 args->info->ifindex = 0;
476 ns = NULL;
477 }
478
479 up_read(&bpf_devs_lock);
480 rtnl_unlock();
481
482 return ns;
483}
484
485int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map)
486{
487 struct ns_get_path_bpf_map_args args = {
488 .offmap = map_to_offmap(map),
489 .info = info,
490 };
491 struct inode *ns_inode;
492 struct path ns_path;
493 void *res;
494
495 res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
496 if (IS_ERR(res)) {
497 if (!info->ifindex)
498 return -ENODEV;
499 return PTR_ERR(res);
500 }
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
510static bool __bpf_offload_dev_match(struct bpf_prog *prog,
511 struct net_device *netdev)
512{
513 struct bpf_offload_netdev *ondev1, *ondev2;
514 struct bpf_prog_offload *offload;
515
516 if (!bpf_prog_is_dev_bound(prog->aux))
517 return false;
518
519 offload = prog->aux->offload;
520 if (!offload)
521 return false;
522 if (offload->netdev == netdev)
523 return true;
524
525 ondev1 = bpf_offload_find_netdev(offload->netdev);
526 ondev2 = bpf_offload_find_netdev(netdev);
527
528 return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev;
529}
530
531bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev)
532{
533 bool ret;
534
535 down_read(&bpf_devs_lock);
536 ret = __bpf_offload_dev_match(prog, netdev);
537 up_read(&bpf_devs_lock);
538
539 return ret;
540}
541EXPORT_SYMBOL_GPL(bpf_offload_dev_match);
542
543bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map)
544{
545 struct bpf_offloaded_map *offmap;
546 bool ret;
547
548 if (!bpf_map_is_dev_bound(map))
549 return bpf_map_offload_neutral(map);
550 offmap = map_to_offmap(map);
551
552 down_read(&bpf_devs_lock);
553 ret = __bpf_offload_dev_match(prog, offmap->netdev);
554 up_read(&bpf_devs_lock);
555
556 return ret;
557}
558
559int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
560 struct net_device *netdev)
561{
562 struct bpf_offload_netdev *ondev;
563 int err;
564
565 ondev = kzalloc(sizeof(*ondev), GFP_KERNEL);
566 if (!ondev)
567 return -ENOMEM;
568
569 ondev->netdev = netdev;
570 ondev->offdev = offdev;
571 INIT_LIST_HEAD(&ondev->progs);
572 INIT_LIST_HEAD(&ondev->maps);
573
574 down_write(&bpf_devs_lock);
575 err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params);
576 if (err) {
577 netdev_warn(netdev, "failed to register for BPF offload\n");
578 goto err_unlock_free;
579 }
580
581 list_add(&ondev->offdev_netdevs, &offdev->netdevs);
582 up_write(&bpf_devs_lock);
583 return 0;
584
585err_unlock_free:
586 up_write(&bpf_devs_lock);
587 kfree(ondev);
588 return err;
589}
590EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register);
591
592void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
593 struct net_device *netdev)
594{
595 struct bpf_offload_netdev *ondev, *altdev;
596 struct bpf_offloaded_map *offmap, *mtmp;
597 struct bpf_prog_offload *offload, *ptmp;
598
599 ASSERT_RTNL();
600
601 down_write(&bpf_devs_lock);
602 ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
603 if (WARN_ON(!ondev))
604 goto unlock;
605
606 WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params));
607 list_del(&ondev->offdev_netdevs);
608
609 /* Try to move the objects to another netdev of the device */
610 altdev = list_first_entry_or_null(&offdev->netdevs,
611 struct bpf_offload_netdev,
612 offdev_netdevs);
613 if (altdev) {
614 list_for_each_entry(offload, &ondev->progs, offloads)
615 offload->netdev = altdev->netdev;
616 list_splice_init(&ondev->progs, &altdev->progs);
617
618 list_for_each_entry(offmap, &ondev->maps, offloads)
619 offmap->netdev = altdev->netdev;
620 list_splice_init(&ondev->maps, &altdev->maps);
621 } else {
622 list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads)
623 __bpf_prog_offload_destroy(offload->prog);
624 list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads)
625 __bpf_map_offload_destroy(offmap);
626 }
627
628 WARN_ON(!list_empty(&ondev->progs));
629 WARN_ON(!list_empty(&ondev->maps));
630 kfree(ondev);
631unlock:
632 up_write(&bpf_devs_lock);
633}
634EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister);
635
636struct bpf_offload_dev *
637bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops)
638{
639 struct bpf_offload_dev *offdev;
640 int err;
641
642 down_write(&bpf_devs_lock);
643 if (!offdevs_inited) {
644 err = rhashtable_init(&offdevs, &offdevs_params);
645 if (err)
646 return ERR_PTR(err);
647 offdevs_inited = true;
648 }
649 up_write(&bpf_devs_lock);
650
651 offdev = kzalloc(sizeof(*offdev), GFP_KERNEL);
652 if (!offdev)
653 return ERR_PTR(-ENOMEM);
654
655 offdev->ops = ops;
656 INIT_LIST_HEAD(&offdev->netdevs);
657
658 return offdev;
659}
660EXPORT_SYMBOL_GPL(bpf_offload_dev_create);
661
662void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev)
663{
664 WARN_ON(!list_empty(&offdev->netdevs));
665 kfree(offdev);
666}
667EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy);