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[linux.git] / drivers / net / netdevsim / bpf.c
1 /*
2  * Copyright (C) 2017 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/debugfs.h>
19 #include <linux/kernel.h>
20 #include <linux/mutex.h>
21 #include <linux/rtnetlink.h>
22 #include <net/pkt_cls.h>
23
24 #include "netdevsim.h"
25
26 #define pr_vlog(env, fmt, ...)  \
27         bpf_verifier_log_write(env, "[netdevsim] " fmt, ##__VA_ARGS__)
28
29 struct nsim_bpf_bound_prog {
30         struct nsim_dev *nsim_dev;
31         struct bpf_prog *prog;
32         struct dentry *ddir;
33         const char *state;
34         bool is_loaded;
35         struct list_head l;
36 };
37
38 #define NSIM_BPF_MAX_KEYS               2
39
40 struct nsim_bpf_bound_map {
41         struct netdevsim *ns;
42         struct bpf_offloaded_map *map;
43         struct mutex mutex;
44         struct nsim_map_entry {
45                 void *key;
46                 void *value;
47         } entry[NSIM_BPF_MAX_KEYS];
48         struct list_head l;
49 };
50
51 static int nsim_bpf_string_show(struct seq_file *file, void *data)
52 {
53         const char **str = file->private;
54
55         if (*str)
56                 seq_printf(file, "%s\n", *str);
57
58         return 0;
59 }
60 DEFINE_SHOW_ATTRIBUTE(nsim_bpf_string);
61
62 static int
63 nsim_bpf_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn)
64 {
65         struct nsim_bpf_bound_prog *state;
66
67         state = env->prog->aux->offload->dev_priv;
68         if (state->nsim_dev->bpf_bind_verifier_delay && !insn_idx)
69                 msleep(state->nsim_dev->bpf_bind_verifier_delay);
70
71         if (insn_idx == env->prog->len - 1)
72                 pr_vlog(env, "Hello from netdevsim!\n");
73
74         return 0;
75 }
76
77 static int nsim_bpf_finalize(struct bpf_verifier_env *env)
78 {
79         return 0;
80 }
81
82 static bool nsim_xdp_offload_active(struct netdevsim *ns)
83 {
84         return ns->xdp_hw.prog;
85 }
86
87 static void nsim_prog_set_loaded(struct bpf_prog *prog, bool loaded)
88 {
89         struct nsim_bpf_bound_prog *state;
90
91         if (!prog || !prog->aux->offload)
92                 return;
93
94         state = prog->aux->offload->dev_priv;
95         state->is_loaded = loaded;
96 }
97
98 static int
99 nsim_bpf_offload(struct netdevsim *ns, struct bpf_prog *prog, bool oldprog)
100 {
101         nsim_prog_set_loaded(ns->bpf_offloaded, false);
102
103         WARN(!!ns->bpf_offloaded != oldprog,
104              "bad offload state, expected offload %sto be active",
105              oldprog ? "" : "not ");
106         ns->bpf_offloaded = prog;
107         ns->bpf_offloaded_id = prog ? prog->aux->id : 0;
108         nsim_prog_set_loaded(prog, true);
109
110         return 0;
111 }
112
113 int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
114                                void *type_data, void *cb_priv)
115 {
116         struct tc_cls_bpf_offload *cls_bpf = type_data;
117         struct bpf_prog *prog = cls_bpf->prog;
118         struct netdevsim *ns = cb_priv;
119         struct bpf_prog *oldprog;
120
121         if (type != TC_SETUP_CLSBPF) {
122                 NSIM_EA(cls_bpf->common.extack,
123                         "only offload of BPF classifiers supported");
124                 return -EOPNOTSUPP;
125         }
126
127         if (!tc_cls_can_offload_and_chain0(ns->netdev, &cls_bpf->common))
128                 return -EOPNOTSUPP;
129
130         if (cls_bpf->common.protocol != htons(ETH_P_ALL)) {
131                 NSIM_EA(cls_bpf->common.extack,
132                         "only ETH_P_ALL supported as filter protocol");
133                 return -EOPNOTSUPP;
134         }
135
136         if (!ns->bpf_tc_accept) {
137                 NSIM_EA(cls_bpf->common.extack,
138                         "netdevsim configured to reject BPF TC offload");
139                 return -EOPNOTSUPP;
140         }
141         /* Note: progs without skip_sw will probably not be dev bound */
142         if (prog && !prog->aux->offload && !ns->bpf_tc_non_bound_accept) {
143                 NSIM_EA(cls_bpf->common.extack,
144                         "netdevsim configured to reject unbound programs");
145                 return -EOPNOTSUPP;
146         }
147
148         if (cls_bpf->command != TC_CLSBPF_OFFLOAD)
149                 return -EOPNOTSUPP;
150
151         oldprog = cls_bpf->oldprog;
152
153         /* Don't remove if oldprog doesn't match driver's state */
154         if (ns->bpf_offloaded != oldprog) {
155                 oldprog = NULL;
156                 if (!cls_bpf->prog)
157                         return 0;
158                 if (ns->bpf_offloaded) {
159                         NSIM_EA(cls_bpf->common.extack,
160                                 "driver and netdev offload states mismatch");
161                         return -EBUSY;
162                 }
163         }
164
165         return nsim_bpf_offload(ns, cls_bpf->prog, oldprog);
166 }
167
168 int nsim_bpf_disable_tc(struct netdevsim *ns)
169 {
170         if (ns->bpf_offloaded && !nsim_xdp_offload_active(ns))
171                 return -EBUSY;
172         return 0;
173 }
174
175 static int nsim_xdp_offload_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
176 {
177         if (!nsim_xdp_offload_active(ns) && !bpf->prog)
178                 return 0;
179         if (!nsim_xdp_offload_active(ns) && bpf->prog && ns->bpf_offloaded) {
180                 NSIM_EA(bpf->extack, "TC program is already loaded");
181                 return -EBUSY;
182         }
183
184         return nsim_bpf_offload(ns, bpf->prog, nsim_xdp_offload_active(ns));
185 }
186
187 static int
188 nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf,
189                   struct xdp_attachment_info *xdp)
190 {
191         int err;
192
193         if (!xdp_attachment_flags_ok(xdp, bpf))
194                 return -EBUSY;
195
196         if (bpf->command == XDP_SETUP_PROG && !ns->bpf_xdpdrv_accept) {
197                 NSIM_EA(bpf->extack, "driver XDP disabled in DebugFS");
198                 return -EOPNOTSUPP;
199         }
200         if (bpf->command == XDP_SETUP_PROG_HW && !ns->bpf_xdpoffload_accept) {
201                 NSIM_EA(bpf->extack, "XDP offload disabled in DebugFS");
202                 return -EOPNOTSUPP;
203         }
204
205         if (bpf->command == XDP_SETUP_PROG_HW) {
206                 err = nsim_xdp_offload_prog(ns, bpf);
207                 if (err)
208                         return err;
209         }
210
211         xdp_attachment_setup(xdp, bpf);
212
213         return 0;
214 }
215
216 static int nsim_bpf_create_prog(struct nsim_dev *nsim_dev,
217                                 struct bpf_prog *prog)
218 {
219         struct nsim_bpf_bound_prog *state;
220         char name[16];
221
222         state = kzalloc(sizeof(*state), GFP_KERNEL);
223         if (!state)
224                 return -ENOMEM;
225
226         state->nsim_dev = nsim_dev;
227         state->prog = prog;
228         state->state = "verify";
229
230         /* Program id is not populated yet when we create the state. */
231         sprintf(name, "%u", nsim_dev->prog_id_gen++);
232         state->ddir = debugfs_create_dir(name, nsim_dev->ddir_bpf_bound_progs);
233         if (IS_ERR_OR_NULL(state->ddir)) {
234                 kfree(state);
235                 return -ENOMEM;
236         }
237
238         debugfs_create_u32("id", 0400, state->ddir, &prog->aux->id);
239         debugfs_create_file("state", 0400, state->ddir,
240                             &state->state, &nsim_bpf_string_fops);
241         debugfs_create_bool("loaded", 0400, state->ddir, &state->is_loaded);
242
243         list_add_tail(&state->l, &nsim_dev->bpf_bound_progs);
244
245         prog->aux->offload->dev_priv = state;
246
247         return 0;
248 }
249
250 static int nsim_bpf_verifier_prep(struct bpf_prog *prog)
251 {
252         struct nsim_dev *nsim_dev =
253                         bpf_offload_dev_priv(prog->aux->offload->offdev);
254
255         if (!nsim_dev->bpf_bind_accept)
256                 return -EOPNOTSUPP;
257
258         return nsim_bpf_create_prog(nsim_dev, prog);
259 }
260
261 static int nsim_bpf_translate(struct bpf_prog *prog)
262 {
263         struct nsim_bpf_bound_prog *state = prog->aux->offload->dev_priv;
264
265         state->state = "xlated";
266         return 0;
267 }
268
269 static void nsim_bpf_destroy_prog(struct bpf_prog *prog)
270 {
271         struct nsim_bpf_bound_prog *state;
272
273         state = prog->aux->offload->dev_priv;
274         WARN(state->is_loaded,
275              "offload state destroyed while program still bound");
276         debugfs_remove_recursive(state->ddir);
277         list_del(&state->l);
278         kfree(state);
279 }
280
281 static const struct bpf_prog_offload_ops nsim_bpf_dev_ops = {
282         .insn_hook      = nsim_bpf_verify_insn,
283         .finalize       = nsim_bpf_finalize,
284         .prepare        = nsim_bpf_verifier_prep,
285         .translate      = nsim_bpf_translate,
286         .destroy        = nsim_bpf_destroy_prog,
287 };
288
289 static int nsim_setup_prog_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
290 {
291         if (bpf->prog && bpf->prog->aux->offload) {
292                 NSIM_EA(bpf->extack, "attempt to load offloaded prog to drv");
293                 return -EINVAL;
294         }
295         if (ns->netdev->mtu > NSIM_XDP_MAX_MTU) {
296                 NSIM_EA(bpf->extack, "MTU too large w/ XDP enabled");
297                 return -EINVAL;
298         }
299         return 0;
300 }
301
302 static int
303 nsim_setup_prog_hw_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
304 {
305         struct nsim_bpf_bound_prog *state;
306
307         if (!bpf->prog)
308                 return 0;
309
310         if (!bpf->prog->aux->offload) {
311                 NSIM_EA(bpf->extack, "xdpoffload of non-bound program");
312                 return -EINVAL;
313         }
314         if (!bpf_offload_dev_match(bpf->prog, ns->netdev)) {
315                 NSIM_EA(bpf->extack, "program bound to different dev");
316                 return -EINVAL;
317         }
318
319         state = bpf->prog->aux->offload->dev_priv;
320         if (WARN_ON(strcmp(state->state, "xlated"))) {
321                 NSIM_EA(bpf->extack, "offloading program in bad state");
322                 return -EINVAL;
323         }
324         return 0;
325 }
326
327 static bool
328 nsim_map_key_match(struct bpf_map *map, struct nsim_map_entry *e, void *key)
329 {
330         return e->key && !memcmp(key, e->key, map->key_size);
331 }
332
333 static int nsim_map_key_find(struct bpf_offloaded_map *offmap, void *key)
334 {
335         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
336         unsigned int i;
337
338         for (i = 0; i < ARRAY_SIZE(nmap->entry); i++)
339                 if (nsim_map_key_match(&offmap->map, &nmap->entry[i], key))
340                         return i;
341
342         return -ENOENT;
343 }
344
345 static int
346 nsim_map_alloc_elem(struct bpf_offloaded_map *offmap, unsigned int idx)
347 {
348         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
349
350         nmap->entry[idx].key = kmalloc(offmap->map.key_size, GFP_USER);
351         if (!nmap->entry[idx].key)
352                 return -ENOMEM;
353         nmap->entry[idx].value = kmalloc(offmap->map.value_size, GFP_USER);
354         if (!nmap->entry[idx].value) {
355                 kfree(nmap->entry[idx].key);
356                 nmap->entry[idx].key = NULL;
357                 return -ENOMEM;
358         }
359
360         return 0;
361 }
362
363 static int
364 nsim_map_get_next_key(struct bpf_offloaded_map *offmap,
365                       void *key, void *next_key)
366 {
367         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
368         int idx = -ENOENT;
369
370         mutex_lock(&nmap->mutex);
371
372         if (key)
373                 idx = nsim_map_key_find(offmap, key);
374         if (idx == -ENOENT)
375                 idx = 0;
376         else
377                 idx++;
378
379         for (; idx < ARRAY_SIZE(nmap->entry); idx++) {
380                 if (nmap->entry[idx].key) {
381                         memcpy(next_key, nmap->entry[idx].key,
382                                offmap->map.key_size);
383                         break;
384                 }
385         }
386
387         mutex_unlock(&nmap->mutex);
388
389         if (idx == ARRAY_SIZE(nmap->entry))
390                 return -ENOENT;
391         return 0;
392 }
393
394 static int
395 nsim_map_lookup_elem(struct bpf_offloaded_map *offmap, void *key, void *value)
396 {
397         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
398         int idx;
399
400         mutex_lock(&nmap->mutex);
401
402         idx = nsim_map_key_find(offmap, key);
403         if (idx >= 0)
404                 memcpy(value, nmap->entry[idx].value, offmap->map.value_size);
405
406         mutex_unlock(&nmap->mutex);
407
408         return idx < 0 ? idx : 0;
409 }
410
411 static int
412 nsim_map_update_elem(struct bpf_offloaded_map *offmap,
413                      void *key, void *value, u64 flags)
414 {
415         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
416         int idx, err = 0;
417
418         mutex_lock(&nmap->mutex);
419
420         idx = nsim_map_key_find(offmap, key);
421         if (idx < 0 && flags == BPF_EXIST) {
422                 err = idx;
423                 goto exit_unlock;
424         }
425         if (idx >= 0 && flags == BPF_NOEXIST) {
426                 err = -EEXIST;
427                 goto exit_unlock;
428         }
429
430         if (idx < 0) {
431                 for (idx = 0; idx < ARRAY_SIZE(nmap->entry); idx++)
432                         if (!nmap->entry[idx].key)
433                                 break;
434                 if (idx == ARRAY_SIZE(nmap->entry)) {
435                         err = -E2BIG;
436                         goto exit_unlock;
437                 }
438
439                 err = nsim_map_alloc_elem(offmap, idx);
440                 if (err)
441                         goto exit_unlock;
442         }
443
444         memcpy(nmap->entry[idx].key, key, offmap->map.key_size);
445         memcpy(nmap->entry[idx].value, value, offmap->map.value_size);
446 exit_unlock:
447         mutex_unlock(&nmap->mutex);
448
449         return err;
450 }
451
452 static int nsim_map_delete_elem(struct bpf_offloaded_map *offmap, void *key)
453 {
454         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
455         int idx;
456
457         if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY)
458                 return -EINVAL;
459
460         mutex_lock(&nmap->mutex);
461
462         idx = nsim_map_key_find(offmap, key);
463         if (idx >= 0) {
464                 kfree(nmap->entry[idx].key);
465                 kfree(nmap->entry[idx].value);
466                 memset(&nmap->entry[idx], 0, sizeof(nmap->entry[idx]));
467         }
468
469         mutex_unlock(&nmap->mutex);
470
471         return idx < 0 ? idx : 0;
472 }
473
474 static const struct bpf_map_dev_ops nsim_bpf_map_ops = {
475         .map_get_next_key       = nsim_map_get_next_key,
476         .map_lookup_elem        = nsim_map_lookup_elem,
477         .map_update_elem        = nsim_map_update_elem,
478         .map_delete_elem        = nsim_map_delete_elem,
479 };
480
481 static int
482 nsim_bpf_map_alloc(struct netdevsim *ns, struct bpf_offloaded_map *offmap)
483 {
484         struct nsim_bpf_bound_map *nmap;
485         int i, err;
486
487         if (WARN_ON(offmap->map.map_type != BPF_MAP_TYPE_ARRAY &&
488                     offmap->map.map_type != BPF_MAP_TYPE_HASH))
489                 return -EINVAL;
490         if (offmap->map.max_entries > NSIM_BPF_MAX_KEYS)
491                 return -ENOMEM;
492         if (offmap->map.map_flags)
493                 return -EINVAL;
494
495         nmap = kzalloc(sizeof(*nmap), GFP_USER);
496         if (!nmap)
497                 return -ENOMEM;
498
499         offmap->dev_priv = nmap;
500         nmap->ns = ns;
501         nmap->map = offmap;
502         mutex_init(&nmap->mutex);
503
504         if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY) {
505                 for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
506                         u32 *key;
507
508                         err = nsim_map_alloc_elem(offmap, i);
509                         if (err)
510                                 goto err_free;
511                         key = nmap->entry[i].key;
512                         *key = i;
513                 }
514         }
515
516         offmap->dev_ops = &nsim_bpf_map_ops;
517         list_add_tail(&nmap->l, &ns->nsim_dev->bpf_bound_maps);
518
519         return 0;
520
521 err_free:
522         while (--i >= 0) {
523                 kfree(nmap->entry[i].key);
524                 kfree(nmap->entry[i].value);
525         }
526         kfree(nmap);
527         return err;
528 }
529
530 static void nsim_bpf_map_free(struct bpf_offloaded_map *offmap)
531 {
532         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
533         unsigned int i;
534
535         for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
536                 kfree(nmap->entry[i].key);
537                 kfree(nmap->entry[i].value);
538         }
539         list_del_init(&nmap->l);
540         mutex_destroy(&nmap->mutex);
541         kfree(nmap);
542 }
543
544 int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
545 {
546         struct netdevsim *ns = netdev_priv(dev);
547         int err;
548
549         ASSERT_RTNL();
550
551         switch (bpf->command) {
552         case XDP_QUERY_PROG:
553                 return xdp_attachment_query(&ns->xdp, bpf);
554         case XDP_QUERY_PROG_HW:
555                 return xdp_attachment_query(&ns->xdp_hw, bpf);
556         case XDP_SETUP_PROG:
557                 err = nsim_setup_prog_checks(ns, bpf);
558                 if (err)
559                         return err;
560
561                 return nsim_xdp_set_prog(ns, bpf, &ns->xdp);
562         case XDP_SETUP_PROG_HW:
563                 err = nsim_setup_prog_hw_checks(ns, bpf);
564                 if (err)
565                         return err;
566
567                 return nsim_xdp_set_prog(ns, bpf, &ns->xdp_hw);
568         case BPF_OFFLOAD_MAP_ALLOC:
569                 if (!ns->bpf_map_accept)
570                         return -EOPNOTSUPP;
571
572                 return nsim_bpf_map_alloc(ns, bpf->offmap);
573         case BPF_OFFLOAD_MAP_FREE:
574                 nsim_bpf_map_free(bpf->offmap);
575                 return 0;
576         default:
577                 return -EINVAL;
578         }
579 }
580
581 int nsim_bpf_dev_init(struct nsim_dev *nsim_dev)
582 {
583         int err;
584
585         INIT_LIST_HEAD(&nsim_dev->bpf_bound_progs);
586         INIT_LIST_HEAD(&nsim_dev->bpf_bound_maps);
587
588         nsim_dev->ddir_bpf_bound_progs = debugfs_create_dir("bpf_bound_progs",
589                                                             nsim_dev->ddir);
590         if (IS_ERR_OR_NULL(nsim_dev->ddir_bpf_bound_progs))
591                 return -ENOMEM;
592
593         nsim_dev->bpf_dev = bpf_offload_dev_create(&nsim_bpf_dev_ops, nsim_dev);
594         err = PTR_ERR_OR_ZERO(nsim_dev->bpf_dev);
595         if (err)
596                 return err;
597
598         nsim_dev->bpf_bind_accept = true;
599         debugfs_create_bool("bpf_bind_accept", 0600, nsim_dev->ddir,
600                             &nsim_dev->bpf_bind_accept);
601         debugfs_create_u32("bpf_bind_verifier_delay", 0600, nsim_dev->ddir,
602                            &nsim_dev->bpf_bind_verifier_delay);
603         return 0;
604 }
605
606 void nsim_bpf_dev_exit(struct nsim_dev *nsim_dev)
607 {
608         WARN_ON(!list_empty(&nsim_dev->bpf_bound_progs));
609         WARN_ON(!list_empty(&nsim_dev->bpf_bound_maps));
610         bpf_offload_dev_destroy(nsim_dev->bpf_dev);
611 }
612
613 int nsim_bpf_init(struct netdevsim *ns)
614 {
615         struct dentry *ddir = ns->nsim_dev_port->ddir;
616         int err;
617
618         err = bpf_offload_dev_netdev_register(ns->nsim_dev->bpf_dev,
619                                               ns->netdev);
620         if (err)
621                 return err;
622
623         debugfs_create_u32("bpf_offloaded_id", 0400, ddir,
624                            &ns->bpf_offloaded_id);
625
626         ns->bpf_tc_accept = true;
627         debugfs_create_bool("bpf_tc_accept", 0600, ddir,
628                             &ns->bpf_tc_accept);
629         debugfs_create_bool("bpf_tc_non_bound_accept", 0600, ddir,
630                             &ns->bpf_tc_non_bound_accept);
631         ns->bpf_xdpdrv_accept = true;
632         debugfs_create_bool("bpf_xdpdrv_accept", 0600, ddir,
633                             &ns->bpf_xdpdrv_accept);
634         ns->bpf_xdpoffload_accept = true;
635         debugfs_create_bool("bpf_xdpoffload_accept", 0600, ddir,
636                             &ns->bpf_xdpoffload_accept);
637
638         ns->bpf_map_accept = true;
639         debugfs_create_bool("bpf_map_accept", 0600, ddir,
640                             &ns->bpf_map_accept);
641
642         return 0;
643 }
644
645 void nsim_bpf_uninit(struct netdevsim *ns)
646 {
647         WARN_ON(ns->xdp.prog);
648         WARN_ON(ns->xdp_hw.prog);
649         WARN_ON(ns->bpf_offloaded);
650         bpf_offload_dev_netdev_unregister(ns->nsim_dev->bpf_dev, ns->netdev);
651 }
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