projects/linux·blob v5.1 · refs

710 lines · 16.3 KiB

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 void *priv;
39};
40
41struct bpf_offload_netdev {
42 struct rhash_head l;
43 struct net_device *netdev;
44 struct bpf_offload_dev *offdev;
45 struct list_head progs;
46 struct list_head maps;
47 struct list_head offdev_netdevs;
48};
49
50static const struct rhashtable_params offdevs_params = {
51 .nelem_hint = 4,
52 .key_len = sizeof(struct net_device *),
53 .key_offset = offsetof(struct bpf_offload_netdev, netdev),
54 .head_offset = offsetof(struct bpf_offload_netdev, l),
55 .automatic_shrinking = true,
56};
57
58static struct rhashtable offdevs;
59static bool offdevs_inited;
60
61static 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
70static struct bpf_offload_netdev *
71bpf_offload_find_netdev(struct net_device *netdev)
72{
73 lockdep_assert_held(&bpf_devs_lock);
74
75 if (!offdevs_inited)
76 return NULL;
77 return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
78}
79
80int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
81{
82 struct bpf_offload_netdev *ondev;
83 struct bpf_prog_offload *offload;
84 int err;
85
86 if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS &&
87 attr->prog_type != BPF_PROG_TYPE_XDP)
88 return -EINVAL;
89
90 if (attr->prog_flags)
91 return -EINVAL;
92
93 offload = kzalloc(sizeof(*offload), GFP_USER);
94 if (!offload)
95 return -ENOMEM;
96
97 offload->prog = prog;
98
99 offload->netdev = dev_get_by_index(current->nsproxy->net_ns,
100 attr->prog_ifindex);
101 err = bpf_dev_offload_check(offload->netdev);
102 if (err)
103 goto err_maybe_put;
104
105 down_write(&bpf_devs_lock);
106 ondev = bpf_offload_find_netdev(offload->netdev);
107 if (!ondev) {
108 err = -EINVAL;
109 goto err_unlock;
110 }
111 offload->offdev = ondev->offdev;
112 prog->aux->offload = offload;
113 list_add_tail(&offload->offloads, &ondev->progs);
114 dev_put(offload->netdev);
115 up_write(&bpf_devs_lock);
116
117 return 0;
118err_unlock:
119 up_write(&bpf_devs_lock);
120err_maybe_put:
121 if (offload->netdev)
122 dev_put(offload->netdev);
123 kfree(offload);
124 return err;
125}
126
127int bpf_prog_offload_verifier_prep(struct bpf_prog *prog)
128{
129 struct bpf_prog_offload *offload;
130 int ret = -ENODEV;
131
132 down_read(&bpf_devs_lock);
133 offload = prog->aux->offload;
134 if (offload) {
135 ret = offload->offdev->ops->prepare(prog);
136 offload->dev_state = !ret;
137 }
138 up_read(&bpf_devs_lock);
139
140 return ret;
141}
142
143int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
144 int insn_idx, int prev_insn_idx)
145{
146 struct bpf_prog_offload *offload;
147 int ret = -ENODEV;
148
149 down_read(&bpf_devs_lock);
150 offload = env->prog->aux->offload;
151 if (offload)
152 ret = offload->offdev->ops->insn_hook(env, insn_idx,
153 prev_insn_idx);
154 up_read(&bpf_devs_lock);
155
156 return ret;
157}
158
159int bpf_prog_offload_finalize(struct bpf_verifier_env *env)
160{
161 struct bpf_prog_offload *offload;
162 int ret = -ENODEV;
163
164 down_read(&bpf_devs_lock);
165 offload = env->prog->aux->offload;
166 if (offload) {
167 if (offload->offdev->ops->finalize)
168 ret = offload->offdev->ops->finalize(env);
169 else
170 ret = 0;
171 }
172 up_read(&bpf_devs_lock);
173
174 return ret;
175}
176
177void
178bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
179 struct bpf_insn *insn)
180{
181 const struct bpf_prog_offload_ops *ops;
182 struct bpf_prog_offload *offload;
183 int ret = -EOPNOTSUPP;
184
185 down_read(&bpf_devs_lock);
186 offload = env->prog->aux->offload;
187 if (offload) {
188 ops = offload->offdev->ops;
189 if (!offload->opt_failed && ops->replace_insn)
190 ret = ops->replace_insn(env, off, insn);
191 offload->opt_failed |= ret;
192 }
193 up_read(&bpf_devs_lock);
194}
195
196void
197bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
198{
199 struct bpf_prog_offload *offload;
200 int ret = -EOPNOTSUPP;
201
202 down_read(&bpf_devs_lock);
203 offload = env->prog->aux->offload;
204 if (offload) {
205 if (!offload->opt_failed && offload->offdev->ops->remove_insns)
206 ret = offload->offdev->ops->remove_insns(env, off, cnt);
207 offload->opt_failed |= ret;
208 }
209 up_read(&bpf_devs_lock);
210}
211
212static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
213{
214 struct bpf_prog_offload *offload = prog->aux->offload;
215
216 if (offload->dev_state)
217 offload->offdev->ops->destroy(prog);
218
219 /* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */
220 bpf_prog_free_id(prog, true);
221
222 list_del_init(&offload->offloads);
223 kfree(offload);
224 prog->aux->offload = NULL;
225}
226
227void bpf_prog_offload_destroy(struct bpf_prog *prog)
228{
229 down_write(&bpf_devs_lock);
230 if (prog->aux->offload)
231 __bpf_prog_offload_destroy(prog);
232 up_write(&bpf_devs_lock);
233}
234
235static int bpf_prog_offload_translate(struct bpf_prog *prog)
236{
237 struct bpf_prog_offload *offload;
238 int ret = -ENODEV;
239
240 down_read(&bpf_devs_lock);
241 offload = prog->aux->offload;
242 if (offload)
243 ret = offload->offdev->ops->translate(prog);
244 up_read(&bpf_devs_lock);
245
246 return ret;
247}
248
249static unsigned int bpf_prog_warn_on_exec(const void *ctx,
250 const struct bpf_insn *insn)
251{
252 WARN(1, "attempt to execute device eBPF program on the host!");
253 return 0;
254}
255
256int bpf_prog_offload_compile(struct bpf_prog *prog)
257{
258 prog->bpf_func = bpf_prog_warn_on_exec;
259
260 return bpf_prog_offload_translate(prog);
261}
262
263struct ns_get_path_bpf_prog_args {
264 struct bpf_prog *prog;
265 struct bpf_prog_info *info;
266};
267
268static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data)
269{
270 struct ns_get_path_bpf_prog_args *args = private_data;
271 struct bpf_prog_aux *aux = args->prog->aux;
272 struct ns_common *ns;
273 struct net *net;
274
275 rtnl_lock();
276 down_read(&bpf_devs_lock);
277
278 if (aux->offload) {
279 args->info->ifindex = aux->offload->netdev->ifindex;
280 net = dev_net(aux->offload->netdev);
281 get_net(net);
282 ns = &net->ns;
283 } else {
284 args->info->ifindex = 0;
285 ns = NULL;
286 }
287
288 up_read(&bpf_devs_lock);
289 rtnl_unlock();
290
291 return ns;
292}
293
294int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
295 struct bpf_prog *prog)
296{
297 struct ns_get_path_bpf_prog_args args = {
298 .prog = prog,
299 .info = info,
300 };
301 struct bpf_prog_aux *aux = prog->aux;
302 struct inode *ns_inode;
303 struct path ns_path;
304 char __user *uinsns;
305 void *res;
306 u32 ulen;
307
308 res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
309 if (IS_ERR(res)) {
310 if (!info->ifindex)
311 return -ENODEV;
312 return PTR_ERR(res);
313 }
314
315 down_read(&bpf_devs_lock);
316
317 if (!aux->offload) {
318 up_read(&bpf_devs_lock);
319 return -ENODEV;
320 }
321
322 ulen = info->jited_prog_len;
323 info->jited_prog_len = aux->offload->jited_len;
324 if (info->jited_prog_len & ulen) {
325 uinsns = u64_to_user_ptr(info->jited_prog_insns);
326 ulen = min_t(u32, info->jited_prog_len, ulen);
327 if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {
328 up_read(&bpf_devs_lock);
329 return -EFAULT;
330 }
331 }
332
333 up_read(&bpf_devs_lock);
334
335 ns_inode = ns_path.dentry->d_inode;
336 info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
337 info->netns_ino = ns_inode->i_ino;
338 path_put(&ns_path);
339
340 return 0;
341}
342
343const struct bpf_prog_ops bpf_offload_prog_ops = {
344};
345
346static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap,
347 enum bpf_netdev_command cmd)
348{
349 struct netdev_bpf data = {};
350 struct net_device *netdev;
351
352 ASSERT_RTNL();
353
354 data.command = cmd;
355 data.offmap = offmap;
356 /* Caller must make sure netdev is valid */
357 netdev = offmap->netdev;
358
359 return netdev->netdev_ops->ndo_bpf(netdev, &data);
360}
361
362struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr)
363{
364 struct net *net = current->nsproxy->net_ns;
365 struct bpf_offload_netdev *ondev;
366 struct bpf_offloaded_map *offmap;
367 int err;
368
369 if (!capable(CAP_SYS_ADMIN))
370 return ERR_PTR(-EPERM);
371 if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
372 attr->map_type != BPF_MAP_TYPE_HASH)
373 return ERR_PTR(-EINVAL);
374
375 offmap = kzalloc(sizeof(*offmap), GFP_USER);
376 if (!offmap)
377 return ERR_PTR(-ENOMEM);
378
379 bpf_map_init_from_attr(&offmap->map, attr);
380
381 rtnl_lock();
382 down_write(&bpf_devs_lock);
383 offmap->netdev = __dev_get_by_index(net, attr->map_ifindex);
384 err = bpf_dev_offload_check(offmap->netdev);
385 if (err)
386 goto err_unlock;
387
388 ondev = bpf_offload_find_netdev(offmap->netdev);
389 if (!ondev) {
390 err = -EINVAL;
391 goto err_unlock;
392 }
393
394 err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC);
395 if (err)
396 goto err_unlock;
397
398 list_add_tail(&offmap->offloads, &ondev->maps);
399 up_write(&bpf_devs_lock);
400 rtnl_unlock();
401
402 return &offmap->map;
403
404err_unlock:
405 up_write(&bpf_devs_lock);
406 rtnl_unlock();
407 kfree(offmap);
408 return ERR_PTR(err);
409}
410
411static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap)
412{
413 WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE));
414 /* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */
415 bpf_map_free_id(&offmap->map, true);
416 list_del_init(&offmap->offloads);
417 offmap->netdev = NULL;
418}
419
420void bpf_map_offload_map_free(struct bpf_map *map)
421{
422 struct bpf_offloaded_map *offmap = map_to_offmap(map);
423
424 rtnl_lock();
425 down_write(&bpf_devs_lock);
426 if (offmap->netdev)
427 __bpf_map_offload_destroy(offmap);
428 up_write(&bpf_devs_lock);
429 rtnl_unlock();
430
431 kfree(offmap);
432}
433
434int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value)
435{
436 struct bpf_offloaded_map *offmap = map_to_offmap(map);
437 int ret = -ENODEV;
438
439 down_read(&bpf_devs_lock);
440 if (offmap->netdev)
441 ret = offmap->dev_ops->map_lookup_elem(offmap, key, value);
442 up_read(&bpf_devs_lock);
443
444 return ret;
445}
446
447int bpf_map_offload_update_elem(struct bpf_map *map,
448 void *key, void *value, u64 flags)
449{
450 struct bpf_offloaded_map *offmap = map_to_offmap(map);
451 int ret = -ENODEV;
452
453 if (unlikely(flags > BPF_EXIST))
454 return -EINVAL;
455
456 down_read(&bpf_devs_lock);
457 if (offmap->netdev)
458 ret = offmap->dev_ops->map_update_elem(offmap, key, value,
459 flags);
460 up_read(&bpf_devs_lock);
461
462 return ret;
463}
464
465int bpf_map_offload_delete_elem(struct bpf_map *map, void *key)
466{
467 struct bpf_offloaded_map *offmap = map_to_offmap(map);
468 int ret = -ENODEV;
469
470 down_read(&bpf_devs_lock);
471 if (offmap->netdev)
472 ret = offmap->dev_ops->map_delete_elem(offmap, key);
473 up_read(&bpf_devs_lock);
474
475 return ret;
476}
477
478int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key)
479{
480 struct bpf_offloaded_map *offmap = map_to_offmap(map);
481 int ret = -ENODEV;
482
483 down_read(&bpf_devs_lock);
484 if (offmap->netdev)
485 ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key);
486 up_read(&bpf_devs_lock);
487
488 return ret;
489}
490
491struct ns_get_path_bpf_map_args {
492 struct bpf_offloaded_map *offmap;
493 struct bpf_map_info *info;
494};
495
496static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data)
497{
498 struct ns_get_path_bpf_map_args *args = private_data;
499 struct ns_common *ns;
500 struct net *net;
501
502 rtnl_lock();
503 down_read(&bpf_devs_lock);
504
505 if (args->offmap->netdev) {
506 args->info->ifindex = args->offmap->netdev->ifindex;
507 net = dev_net(args->offmap->netdev);
508 get_net(net);
509 ns = &net->ns;
510 } else {
511 args->info->ifindex = 0;
512 ns = NULL;
513 }
514
515 up_read(&bpf_devs_lock);
516 rtnl_unlock();
517
518 return ns;
519}
520
521int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map)
522{
523 struct ns_get_path_bpf_map_args args = {
524 .offmap = map_to_offmap(map),
525 .info = info,
526 };
527 struct inode *ns_inode;
528 struct path ns_path;
529 void *res;
530
531 res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
532 if (IS_ERR(res)) {
533 if (!info->ifindex)
534 return -ENODEV;
535 return PTR_ERR(res);
536 }
537
538 ns_inode = ns_path.dentry->d_inode;
539 info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
540 info->netns_ino = ns_inode->i_ino;
541 path_put(&ns_path);
542
543 return 0;
544}
545
546static bool __bpf_offload_dev_match(struct bpf_prog *prog,
547 struct net_device *netdev)
548{
549 struct bpf_offload_netdev *ondev1, *ondev2;
550 struct bpf_prog_offload *offload;
551
552 if (!bpf_prog_is_dev_bound(prog->aux))
553 return false;
554
555 offload = prog->aux->offload;
556 if (!offload)
557 return false;
558 if (offload->netdev == netdev)
559 return true;
560
561 ondev1 = bpf_offload_find_netdev(offload->netdev);
562 ondev2 = bpf_offload_find_netdev(netdev);
563
564 return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev;
565}
566
567bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev)
568{
569 bool ret;
570
571 down_read(&bpf_devs_lock);
572 ret = __bpf_offload_dev_match(prog, netdev);
573 up_read(&bpf_devs_lock);
574
575 return ret;
576}
577EXPORT_SYMBOL_GPL(bpf_offload_dev_match);
578
579bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map)
580{
581 struct bpf_offloaded_map *offmap;
582 bool ret;
583
584 if (!bpf_map_is_dev_bound(map))
585 return bpf_map_offload_neutral(map);
586 offmap = map_to_offmap(map);
587
588 down_read(&bpf_devs_lock);
589 ret = __bpf_offload_dev_match(prog, offmap->netdev);
590 up_read(&bpf_devs_lock);
591
592 return ret;
593}
594
595int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
596 struct net_device *netdev)
597{
598 struct bpf_offload_netdev *ondev;
599 int err;
600
601 ondev = kzalloc(sizeof(*ondev), GFP_KERNEL);
602 if (!ondev)
603 return -ENOMEM;
604
605 ondev->netdev = netdev;
606 ondev->offdev = offdev;
607 INIT_LIST_HEAD(&ondev->progs);
608 INIT_LIST_HEAD(&ondev->maps);
609
610 down_write(&bpf_devs_lock);
611 err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params);
612 if (err) {
613 netdev_warn(netdev, "failed to register for BPF offload\n");
614 goto err_unlock_free;
615 }
616
617 list_add(&ondev->offdev_netdevs, &offdev->netdevs);
618 up_write(&bpf_devs_lock);
619 return 0;
620
621err_unlock_free:
622 up_write(&bpf_devs_lock);
623 kfree(ondev);
624 return err;
625}
626EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register);
627
628void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
629 struct net_device *netdev)
630{
631 struct bpf_offload_netdev *ondev, *altdev;
632 struct bpf_offloaded_map *offmap, *mtmp;
633 struct bpf_prog_offload *offload, *ptmp;
634
635 ASSERT_RTNL();
636
637 down_write(&bpf_devs_lock);
638 ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
639 if (WARN_ON(!ondev))
640 goto unlock;
641
642 WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params));
643 list_del(&ondev->offdev_netdevs);
644
645 /* Try to move the objects to another netdev of the device */
646 altdev = list_first_entry_or_null(&offdev->netdevs,
647 struct bpf_offload_netdev,
648 offdev_netdevs);
649 if (altdev) {
650 list_for_each_entry(offload, &ondev->progs, offloads)
651 offload->netdev = altdev->netdev;
652 list_splice_init(&ondev->progs, &altdev->progs);
653
654 list_for_each_entry(offmap, &ondev->maps, offloads)
655 offmap->netdev = altdev->netdev;
656 list_splice_init(&ondev->maps, &altdev->maps);
657 } else {
658 list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads)
659 __bpf_prog_offload_destroy(offload->prog);
660 list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads)
661 __bpf_map_offload_destroy(offmap);
662 }
663
664 WARN_ON(!list_empty(&ondev->progs));
665 WARN_ON(!list_empty(&ondev->maps));
666 kfree(ondev);
667unlock:
668 up_write(&bpf_devs_lock);
669}
670EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister);
671
672struct bpf_offload_dev *
673bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops, void *priv)
674{
675 struct bpf_offload_dev *offdev;
676 int err;
677
678 down_write(&bpf_devs_lock);
679 if (!offdevs_inited) {
680 err = rhashtable_init(&offdevs, &offdevs_params);
681 if (err)
682 return ERR_PTR(err);
683 offdevs_inited = true;
684 }
685 up_write(&bpf_devs_lock);
686
687 offdev = kzalloc(sizeof(*offdev), GFP_KERNEL);
688 if (!offdev)
689 return ERR_PTR(-ENOMEM);
690
691 offdev->ops = ops;
692 offdev->priv = priv;
693 INIT_LIST_HEAD(&offdev->netdevs);
694
695 return offdev;
696}
697EXPORT_SYMBOL_GPL(bpf_offload_dev_create);
698
699void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev)
700{
701 WARN_ON(!list_empty(&offdev->netdevs));
702 kfree(offdev);
703}
704EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy);
705
706void *bpf_offload_dev_priv(struct bpf_offload_dev *offdev)
707{
708 return offdev->priv;
709}
710EXPORT_SYMBOL_GPL(bpf_offload_dev_priv);