GNU Linux-libre 4.19.286-gnu1
[releases.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 netdevsim *ns;
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_debugfs_bpf_string_read(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
61 static int nsim_debugfs_bpf_string_open(struct inode *inode, struct file *f)
62 {
63         return single_open(f, nsim_debugfs_bpf_string_read, inode->i_private);
64 }
65
66 static const struct file_operations nsim_bpf_string_fops = {
67         .owner = THIS_MODULE,
68         .open = nsim_debugfs_bpf_string_open,
69         .release = single_release,
70         .read = seq_read,
71         .llseek = seq_lseek
72 };
73
74 static int
75 nsim_bpf_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn)
76 {
77         struct nsim_bpf_bound_prog *state;
78
79         state = env->prog->aux->offload->dev_priv;
80         if (state->ns->bpf_bind_verifier_delay && !insn_idx)
81                 msleep(state->ns->bpf_bind_verifier_delay);
82
83         if (insn_idx == env->prog->len - 1)
84                 pr_vlog(env, "Hello from netdevsim!\n");
85
86         return 0;
87 }
88
89 static const struct bpf_prog_offload_ops nsim_bpf_analyzer_ops = {
90         .insn_hook = nsim_bpf_verify_insn,
91 };
92
93 static bool nsim_xdp_offload_active(struct netdevsim *ns)
94 {
95         return ns->xdp_hw.prog;
96 }
97
98 static void nsim_prog_set_loaded(struct bpf_prog *prog, bool loaded)
99 {
100         struct nsim_bpf_bound_prog *state;
101
102         if (!prog || !prog->aux->offload)
103                 return;
104
105         state = prog->aux->offload->dev_priv;
106         state->is_loaded = loaded;
107 }
108
109 static int
110 nsim_bpf_offload(struct netdevsim *ns, struct bpf_prog *prog, bool oldprog)
111 {
112         nsim_prog_set_loaded(ns->bpf_offloaded, false);
113
114         WARN(!!ns->bpf_offloaded != oldprog,
115              "bad offload state, expected offload %sto be active",
116              oldprog ? "" : "not ");
117         ns->bpf_offloaded = prog;
118         ns->bpf_offloaded_id = prog ? prog->aux->id : 0;
119         nsim_prog_set_loaded(prog, true);
120
121         return 0;
122 }
123
124 int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
125                                void *type_data, void *cb_priv)
126 {
127         struct tc_cls_bpf_offload *cls_bpf = type_data;
128         struct bpf_prog *prog = cls_bpf->prog;
129         struct netdevsim *ns = cb_priv;
130         struct bpf_prog *oldprog;
131
132         if (type != TC_SETUP_CLSBPF) {
133                 NSIM_EA(cls_bpf->common.extack,
134                         "only offload of BPF classifiers supported");
135                 return -EOPNOTSUPP;
136         }
137
138         if (!tc_cls_can_offload_and_chain0(ns->netdev, &cls_bpf->common))
139                 return -EOPNOTSUPP;
140
141         if (cls_bpf->common.protocol != htons(ETH_P_ALL)) {
142                 NSIM_EA(cls_bpf->common.extack,
143                         "only ETH_P_ALL supported as filter protocol");
144                 return -EOPNOTSUPP;
145         }
146
147         if (!ns->bpf_tc_accept) {
148                 NSIM_EA(cls_bpf->common.extack,
149                         "netdevsim configured to reject BPF TC offload");
150                 return -EOPNOTSUPP;
151         }
152         /* Note: progs without skip_sw will probably not be dev bound */
153         if (prog && !prog->aux->offload && !ns->bpf_tc_non_bound_accept) {
154                 NSIM_EA(cls_bpf->common.extack,
155                         "netdevsim configured to reject unbound programs");
156                 return -EOPNOTSUPP;
157         }
158
159         if (cls_bpf->command != TC_CLSBPF_OFFLOAD)
160                 return -EOPNOTSUPP;
161
162         oldprog = cls_bpf->oldprog;
163
164         /* Don't remove if oldprog doesn't match driver's state */
165         if (ns->bpf_offloaded != oldprog) {
166                 oldprog = NULL;
167                 if (!cls_bpf->prog)
168                         return 0;
169                 if (ns->bpf_offloaded) {
170                         NSIM_EA(cls_bpf->common.extack,
171                                 "driver and netdev offload states mismatch");
172                         return -EBUSY;
173                 }
174         }
175
176         return nsim_bpf_offload(ns, cls_bpf->prog, oldprog);
177 }
178
179 int nsim_bpf_disable_tc(struct netdevsim *ns)
180 {
181         if (ns->bpf_offloaded && !nsim_xdp_offload_active(ns))
182                 return -EBUSY;
183         return 0;
184 }
185
186 static int nsim_xdp_offload_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
187 {
188         if (!nsim_xdp_offload_active(ns) && !bpf->prog)
189                 return 0;
190         if (!nsim_xdp_offload_active(ns) && bpf->prog && ns->bpf_offloaded) {
191                 NSIM_EA(bpf->extack, "TC program is already loaded");
192                 return -EBUSY;
193         }
194
195         return nsim_bpf_offload(ns, bpf->prog, nsim_xdp_offload_active(ns));
196 }
197
198 static int
199 nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf,
200                   struct xdp_attachment_info *xdp)
201 {
202         int err;
203
204         if (!xdp_attachment_flags_ok(xdp, bpf))
205                 return -EBUSY;
206
207         if (bpf->command == XDP_SETUP_PROG && !ns->bpf_xdpdrv_accept) {
208                 NSIM_EA(bpf->extack, "driver XDP disabled in DebugFS");
209                 return -EOPNOTSUPP;
210         }
211         if (bpf->command == XDP_SETUP_PROG_HW && !ns->bpf_xdpoffload_accept) {
212                 NSIM_EA(bpf->extack, "XDP offload disabled in DebugFS");
213                 return -EOPNOTSUPP;
214         }
215
216         if (bpf->command == XDP_SETUP_PROG_HW) {
217                 err = nsim_xdp_offload_prog(ns, bpf);
218                 if (err)
219                         return err;
220         }
221
222         xdp_attachment_setup(xdp, bpf);
223
224         return 0;
225 }
226
227 static int nsim_bpf_create_prog(struct netdevsim *ns, struct bpf_prog *prog)
228 {
229         struct nsim_bpf_bound_prog *state;
230         char name[16];
231
232         state = kzalloc(sizeof(*state), GFP_KERNEL);
233         if (!state)
234                 return -ENOMEM;
235
236         state->ns = ns;
237         state->prog = prog;
238         state->state = "verify";
239
240         /* Program id is not populated yet when we create the state. */
241         sprintf(name, "%u", ns->sdev->prog_id_gen++);
242         state->ddir = debugfs_create_dir(name, ns->sdev->ddir_bpf_bound_progs);
243         if (IS_ERR_OR_NULL(state->ddir)) {
244                 kfree(state);
245                 return -ENOMEM;
246         }
247
248         debugfs_create_u32("id", 0400, state->ddir, &prog->aux->id);
249         debugfs_create_file("state", 0400, state->ddir,
250                             &state->state, &nsim_bpf_string_fops);
251         debugfs_create_bool("loaded", 0400, state->ddir, &state->is_loaded);
252
253         list_add_tail(&state->l, &ns->sdev->bpf_bound_progs);
254
255         prog->aux->offload->dev_priv = state;
256
257         return 0;
258 }
259
260 static void nsim_bpf_destroy_prog(struct bpf_prog *prog)
261 {
262         struct nsim_bpf_bound_prog *state;
263
264         state = prog->aux->offload->dev_priv;
265         WARN(state->is_loaded,
266              "offload state destroyed while program still bound");
267         debugfs_remove_recursive(state->ddir);
268         list_del(&state->l);
269         kfree(state);
270 }
271
272 static int nsim_setup_prog_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
273 {
274         if (bpf->prog && bpf->prog->aux->offload) {
275                 NSIM_EA(bpf->extack, "attempt to load offloaded prog to drv");
276                 return -EINVAL;
277         }
278         if (ns->netdev->mtu > NSIM_XDP_MAX_MTU) {
279                 NSIM_EA(bpf->extack, "MTU too large w/ XDP enabled");
280                 return -EINVAL;
281         }
282         return 0;
283 }
284
285 static int
286 nsim_setup_prog_hw_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
287 {
288         struct nsim_bpf_bound_prog *state;
289
290         if (!bpf->prog)
291                 return 0;
292
293         if (!bpf->prog->aux->offload) {
294                 NSIM_EA(bpf->extack, "xdpoffload of non-bound program");
295                 return -EINVAL;
296         }
297         if (!bpf_offload_dev_match(bpf->prog, ns->netdev)) {
298                 NSIM_EA(bpf->extack, "program bound to different dev");
299                 return -EINVAL;
300         }
301
302         state = bpf->prog->aux->offload->dev_priv;
303         if (WARN_ON(strcmp(state->state, "xlated"))) {
304                 NSIM_EA(bpf->extack, "offloading program in bad state");
305                 return -EINVAL;
306         }
307         return 0;
308 }
309
310 static bool
311 nsim_map_key_match(struct bpf_map *map, struct nsim_map_entry *e, void *key)
312 {
313         return e->key && !memcmp(key, e->key, map->key_size);
314 }
315
316 static int nsim_map_key_find(struct bpf_offloaded_map *offmap, void *key)
317 {
318         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
319         unsigned int i;
320
321         for (i = 0; i < ARRAY_SIZE(nmap->entry); i++)
322                 if (nsim_map_key_match(&offmap->map, &nmap->entry[i], key))
323                         return i;
324
325         return -ENOENT;
326 }
327
328 static int
329 nsim_map_alloc_elem(struct bpf_offloaded_map *offmap, unsigned int idx)
330 {
331         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
332
333         nmap->entry[idx].key = kmalloc(offmap->map.key_size,
334                                        GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
335         if (!nmap->entry[idx].key)
336                 return -ENOMEM;
337         nmap->entry[idx].value = kmalloc(offmap->map.value_size,
338                                          GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
339         if (!nmap->entry[idx].value) {
340                 kfree(nmap->entry[idx].key);
341                 nmap->entry[idx].key = NULL;
342                 return -ENOMEM;
343         }
344
345         return 0;
346 }
347
348 static int
349 nsim_map_get_next_key(struct bpf_offloaded_map *offmap,
350                       void *key, void *next_key)
351 {
352         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
353         int idx = -ENOENT;
354
355         mutex_lock(&nmap->mutex);
356
357         if (key)
358                 idx = nsim_map_key_find(offmap, key);
359         if (idx == -ENOENT)
360                 idx = 0;
361         else
362                 idx++;
363
364         for (; idx < ARRAY_SIZE(nmap->entry); idx++) {
365                 if (nmap->entry[idx].key) {
366                         memcpy(next_key, nmap->entry[idx].key,
367                                offmap->map.key_size);
368                         break;
369                 }
370         }
371
372         mutex_unlock(&nmap->mutex);
373
374         if (idx == ARRAY_SIZE(nmap->entry))
375                 return -ENOENT;
376         return 0;
377 }
378
379 static int
380 nsim_map_lookup_elem(struct bpf_offloaded_map *offmap, void *key, void *value)
381 {
382         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
383         int idx;
384
385         mutex_lock(&nmap->mutex);
386
387         idx = nsim_map_key_find(offmap, key);
388         if (idx >= 0)
389                 memcpy(value, nmap->entry[idx].value, offmap->map.value_size);
390
391         mutex_unlock(&nmap->mutex);
392
393         return idx < 0 ? idx : 0;
394 }
395
396 static int
397 nsim_map_update_elem(struct bpf_offloaded_map *offmap,
398                      void *key, void *value, u64 flags)
399 {
400         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
401         int idx, err = 0;
402
403         mutex_lock(&nmap->mutex);
404
405         idx = nsim_map_key_find(offmap, key);
406         if (idx < 0 && flags == BPF_EXIST) {
407                 err = idx;
408                 goto exit_unlock;
409         }
410         if (idx >= 0 && flags == BPF_NOEXIST) {
411                 err = -EEXIST;
412                 goto exit_unlock;
413         }
414
415         if (idx < 0) {
416                 for (idx = 0; idx < ARRAY_SIZE(nmap->entry); idx++)
417                         if (!nmap->entry[idx].key)
418                                 break;
419                 if (idx == ARRAY_SIZE(nmap->entry)) {
420                         err = -E2BIG;
421                         goto exit_unlock;
422                 }
423
424                 err = nsim_map_alloc_elem(offmap, idx);
425                 if (err)
426                         goto exit_unlock;
427         }
428
429         memcpy(nmap->entry[idx].key, key, offmap->map.key_size);
430         memcpy(nmap->entry[idx].value, value, offmap->map.value_size);
431 exit_unlock:
432         mutex_unlock(&nmap->mutex);
433
434         return err;
435 }
436
437 static int nsim_map_delete_elem(struct bpf_offloaded_map *offmap, void *key)
438 {
439         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
440         int idx;
441
442         if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY)
443                 return -EINVAL;
444
445         mutex_lock(&nmap->mutex);
446
447         idx = nsim_map_key_find(offmap, key);
448         if (idx >= 0) {
449                 kfree(nmap->entry[idx].key);
450                 kfree(nmap->entry[idx].value);
451                 memset(&nmap->entry[idx], 0, sizeof(nmap->entry[idx]));
452         }
453
454         mutex_unlock(&nmap->mutex);
455
456         return idx < 0 ? idx : 0;
457 }
458
459 static const struct bpf_map_dev_ops nsim_bpf_map_ops = {
460         .map_get_next_key       = nsim_map_get_next_key,
461         .map_lookup_elem        = nsim_map_lookup_elem,
462         .map_update_elem        = nsim_map_update_elem,
463         .map_delete_elem        = nsim_map_delete_elem,
464 };
465
466 static int
467 nsim_bpf_map_alloc(struct netdevsim *ns, struct bpf_offloaded_map *offmap)
468 {
469         struct nsim_bpf_bound_map *nmap;
470         int i, err;
471
472         if (WARN_ON(offmap->map.map_type != BPF_MAP_TYPE_ARRAY &&
473                     offmap->map.map_type != BPF_MAP_TYPE_HASH))
474                 return -EINVAL;
475         if (offmap->map.max_entries > NSIM_BPF_MAX_KEYS)
476                 return -ENOMEM;
477         if (offmap->map.map_flags)
478                 return -EINVAL;
479
480         nmap = kzalloc(sizeof(*nmap), GFP_KERNEL_ACCOUNT);
481         if (!nmap)
482                 return -ENOMEM;
483
484         offmap->dev_priv = nmap;
485         nmap->ns = ns;
486         nmap->map = offmap;
487         mutex_init(&nmap->mutex);
488
489         if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY) {
490                 for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
491                         u32 *key;
492
493                         err = nsim_map_alloc_elem(offmap, i);
494                         if (err)
495                                 goto err_free;
496                         key = nmap->entry[i].key;
497                         *key = i;
498                         memset(nmap->entry[i].value, 0, offmap->map.value_size);
499                 }
500         }
501
502         offmap->dev_ops = &nsim_bpf_map_ops;
503         list_add_tail(&nmap->l, &ns->sdev->bpf_bound_maps);
504
505         return 0;
506
507 err_free:
508         while (--i >= 0) {
509                 kfree(nmap->entry[i].key);
510                 kfree(nmap->entry[i].value);
511         }
512         kfree(nmap);
513         return err;
514 }
515
516 static void nsim_bpf_map_free(struct bpf_offloaded_map *offmap)
517 {
518         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
519         unsigned int i;
520
521         for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
522                 kfree(nmap->entry[i].key);
523                 kfree(nmap->entry[i].value);
524         }
525         list_del_init(&nmap->l);
526         mutex_destroy(&nmap->mutex);
527         kfree(nmap);
528 }
529
530 int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
531 {
532         struct netdevsim *ns = netdev_priv(dev);
533         struct nsim_bpf_bound_prog *state;
534         int err;
535
536         ASSERT_RTNL();
537
538         switch (bpf->command) {
539         case BPF_OFFLOAD_VERIFIER_PREP:
540                 if (!ns->bpf_bind_accept)
541                         return -EOPNOTSUPP;
542
543                 err = nsim_bpf_create_prog(ns, bpf->verifier.prog);
544                 if (err)
545                         return err;
546
547                 bpf->verifier.ops = &nsim_bpf_analyzer_ops;
548                 return 0;
549         case BPF_OFFLOAD_TRANSLATE:
550                 state = bpf->offload.prog->aux->offload->dev_priv;
551
552                 state->state = "xlated";
553                 return 0;
554         case BPF_OFFLOAD_DESTROY:
555                 nsim_bpf_destroy_prog(bpf->offload.prog);
556                 return 0;
557         case XDP_QUERY_PROG:
558                 return xdp_attachment_query(&ns->xdp, bpf);
559         case XDP_QUERY_PROG_HW:
560                 return xdp_attachment_query(&ns->xdp_hw, bpf);
561         case XDP_SETUP_PROG:
562                 err = nsim_setup_prog_checks(ns, bpf);
563                 if (err)
564                         return err;
565
566                 return nsim_xdp_set_prog(ns, bpf, &ns->xdp);
567         case XDP_SETUP_PROG_HW:
568                 err = nsim_setup_prog_hw_checks(ns, bpf);
569                 if (err)
570                         return err;
571
572                 return nsim_xdp_set_prog(ns, bpf, &ns->xdp_hw);
573         case BPF_OFFLOAD_MAP_ALLOC:
574                 if (!ns->bpf_map_accept)
575                         return -EOPNOTSUPP;
576
577                 return nsim_bpf_map_alloc(ns, bpf->offmap);
578         case BPF_OFFLOAD_MAP_FREE:
579                 nsim_bpf_map_free(bpf->offmap);
580                 return 0;
581         default:
582                 return -EINVAL;
583         }
584 }
585
586 int nsim_bpf_init(struct netdevsim *ns)
587 {
588         int err;
589
590         if (ns->sdev->refcnt == 1) {
591                 INIT_LIST_HEAD(&ns->sdev->bpf_bound_progs);
592                 INIT_LIST_HEAD(&ns->sdev->bpf_bound_maps);
593
594                 ns->sdev->ddir_bpf_bound_progs =
595                         debugfs_create_dir("bpf_bound_progs", ns->sdev->ddir);
596                 if (IS_ERR_OR_NULL(ns->sdev->ddir_bpf_bound_progs))
597                         return -ENOMEM;
598
599                 ns->sdev->bpf_dev = bpf_offload_dev_create();
600                 err = PTR_ERR_OR_ZERO(ns->sdev->bpf_dev);
601                 if (err)
602                         return err;
603         }
604
605         err = bpf_offload_dev_netdev_register(ns->sdev->bpf_dev, ns->netdev);
606         if (err)
607                 goto err_destroy_bdev;
608
609         debugfs_create_u32("bpf_offloaded_id", 0400, ns->ddir,
610                            &ns->bpf_offloaded_id);
611
612         ns->bpf_bind_accept = true;
613         debugfs_create_bool("bpf_bind_accept", 0600, ns->ddir,
614                             &ns->bpf_bind_accept);
615         debugfs_create_u32("bpf_bind_verifier_delay", 0600, ns->ddir,
616                            &ns->bpf_bind_verifier_delay);
617
618         ns->bpf_tc_accept = true;
619         debugfs_create_bool("bpf_tc_accept", 0600, ns->ddir,
620                             &ns->bpf_tc_accept);
621         debugfs_create_bool("bpf_tc_non_bound_accept", 0600, ns->ddir,
622                             &ns->bpf_tc_non_bound_accept);
623         ns->bpf_xdpdrv_accept = true;
624         debugfs_create_bool("bpf_xdpdrv_accept", 0600, ns->ddir,
625                             &ns->bpf_xdpdrv_accept);
626         ns->bpf_xdpoffload_accept = true;
627         debugfs_create_bool("bpf_xdpoffload_accept", 0600, ns->ddir,
628                             &ns->bpf_xdpoffload_accept);
629
630         ns->bpf_map_accept = true;
631         debugfs_create_bool("bpf_map_accept", 0600, ns->ddir,
632                             &ns->bpf_map_accept);
633
634         return 0;
635
636 err_destroy_bdev:
637         if (ns->sdev->refcnt == 1)
638                 bpf_offload_dev_destroy(ns->sdev->bpf_dev);
639         return err;
640 }
641
642 void nsim_bpf_uninit(struct netdevsim *ns)
643 {
644         WARN_ON(ns->xdp.prog);
645         WARN_ON(ns->xdp_hw.prog);
646         WARN_ON(ns->bpf_offloaded);
647         bpf_offload_dev_netdev_unregister(ns->sdev->bpf_dev, ns->netdev);
648
649         if (ns->sdev->refcnt == 1) {
650                 WARN_ON(!list_empty(&ns->sdev->bpf_bound_progs));
651                 WARN_ON(!list_empty(&ns->sdev->bpf_bound_maps));
652                 bpf_offload_dev_destroy(ns->sdev->bpf_dev);
653         }
654 }