Merge branch 'kvm-master' into kvm-next
[linux-2.6-microblaze.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         int ret = 0;
67
68         state = env->prog->aux->offload->dev_priv;
69         if (state->nsim_dev->bpf_bind_verifier_delay && !insn_idx)
70                 msleep(state->nsim_dev->bpf_bind_verifier_delay);
71
72         if (insn_idx == env->prog->len - 1) {
73                 pr_vlog(env, "Hello from netdevsim!\n");
74
75                 if (!state->nsim_dev->bpf_bind_verifier_accept)
76                         ret = -EOPNOTSUPP;
77         }
78
79         return ret;
80 }
81
82 static int nsim_bpf_finalize(struct bpf_verifier_env *env)
83 {
84         return 0;
85 }
86
87 static bool nsim_xdp_offload_active(struct netdevsim *ns)
88 {
89         return ns->xdp_hw.prog;
90 }
91
92 static void nsim_prog_set_loaded(struct bpf_prog *prog, bool loaded)
93 {
94         struct nsim_bpf_bound_prog *state;
95
96         if (!prog || !prog->aux->offload)
97                 return;
98
99         state = prog->aux->offload->dev_priv;
100         state->is_loaded = loaded;
101 }
102
103 static int
104 nsim_bpf_offload(struct netdevsim *ns, struct bpf_prog *prog, bool oldprog)
105 {
106         nsim_prog_set_loaded(ns->bpf_offloaded, false);
107
108         WARN(!!ns->bpf_offloaded != oldprog,
109              "bad offload state, expected offload %sto be active",
110              oldprog ? "" : "not ");
111         ns->bpf_offloaded = prog;
112         ns->bpf_offloaded_id = prog ? prog->aux->id : 0;
113         nsim_prog_set_loaded(prog, true);
114
115         return 0;
116 }
117
118 int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
119                                void *type_data, void *cb_priv)
120 {
121         struct tc_cls_bpf_offload *cls_bpf = type_data;
122         struct bpf_prog *prog = cls_bpf->prog;
123         struct netdevsim *ns = cb_priv;
124         struct bpf_prog *oldprog;
125
126         if (type != TC_SETUP_CLSBPF) {
127                 NSIM_EA(cls_bpf->common.extack,
128                         "only offload of BPF classifiers supported");
129                 return -EOPNOTSUPP;
130         }
131
132         if (!tc_cls_can_offload_and_chain0(ns->netdev, &cls_bpf->common))
133                 return -EOPNOTSUPP;
134
135         if (cls_bpf->common.protocol != htons(ETH_P_ALL)) {
136                 NSIM_EA(cls_bpf->common.extack,
137                         "only ETH_P_ALL supported as filter protocol");
138                 return -EOPNOTSUPP;
139         }
140
141         if (!ns->bpf_tc_accept) {
142                 NSIM_EA(cls_bpf->common.extack,
143                         "netdevsim configured to reject BPF TC offload");
144                 return -EOPNOTSUPP;
145         }
146         /* Note: progs without skip_sw will probably not be dev bound */
147         if (prog && !prog->aux->offload && !ns->bpf_tc_non_bound_accept) {
148                 NSIM_EA(cls_bpf->common.extack,
149                         "netdevsim configured to reject unbound programs");
150                 return -EOPNOTSUPP;
151         }
152
153         if (cls_bpf->command != TC_CLSBPF_OFFLOAD)
154                 return -EOPNOTSUPP;
155
156         oldprog = cls_bpf->oldprog;
157
158         /* Don't remove if oldprog doesn't match driver's state */
159         if (ns->bpf_offloaded != oldprog) {
160                 oldprog = NULL;
161                 if (!cls_bpf->prog)
162                         return 0;
163                 if (ns->bpf_offloaded) {
164                         NSIM_EA(cls_bpf->common.extack,
165                                 "driver and netdev offload states mismatch");
166                         return -EBUSY;
167                 }
168         }
169
170         return nsim_bpf_offload(ns, cls_bpf->prog, oldprog);
171 }
172
173 int nsim_bpf_disable_tc(struct netdevsim *ns)
174 {
175         if (ns->bpf_offloaded && !nsim_xdp_offload_active(ns))
176                 return -EBUSY;
177         return 0;
178 }
179
180 static int nsim_xdp_offload_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
181 {
182         if (!nsim_xdp_offload_active(ns) && !bpf->prog)
183                 return 0;
184         if (!nsim_xdp_offload_active(ns) && bpf->prog && ns->bpf_offloaded) {
185                 NSIM_EA(bpf->extack, "TC program is already loaded");
186                 return -EBUSY;
187         }
188
189         return nsim_bpf_offload(ns, bpf->prog, nsim_xdp_offload_active(ns));
190 }
191
192 static int
193 nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf,
194                   struct xdp_attachment_info *xdp)
195 {
196         int err;
197
198         if (bpf->command == XDP_SETUP_PROG && !ns->bpf_xdpdrv_accept) {
199                 NSIM_EA(bpf->extack, "driver XDP disabled in DebugFS");
200                 return -EOPNOTSUPP;
201         }
202         if (bpf->command == XDP_SETUP_PROG_HW && !ns->bpf_xdpoffload_accept) {
203                 NSIM_EA(bpf->extack, "XDP offload disabled in DebugFS");
204                 return -EOPNOTSUPP;
205         }
206
207         if (bpf->command == XDP_SETUP_PROG_HW) {
208                 err = nsim_xdp_offload_prog(ns, bpf);
209                 if (err)
210                         return err;
211         }
212
213         xdp_attachment_setup(xdp, bpf);
214
215         return 0;
216 }
217
218 static int nsim_bpf_create_prog(struct nsim_dev *nsim_dev,
219                                 struct bpf_prog *prog)
220 {
221         struct nsim_bpf_bound_prog *state;
222         char name[16];
223         int ret;
224
225         state = kzalloc(sizeof(*state), GFP_KERNEL);
226         if (!state)
227                 return -ENOMEM;
228
229         state->nsim_dev = nsim_dev;
230         state->prog = prog;
231         state->state = "verify";
232
233         /* Program id is not populated yet when we create the state. */
234         sprintf(name, "%u", nsim_dev->prog_id_gen++);
235         state->ddir = debugfs_create_dir(name, nsim_dev->ddir_bpf_bound_progs);
236         if (IS_ERR(state->ddir)) {
237                 ret = PTR_ERR(state->ddir);
238                 kfree(state);
239                 return ret;
240         }
241
242         debugfs_create_u32("id", 0400, state->ddir, &prog->aux->id);
243         debugfs_create_file("state", 0400, state->ddir,
244                             &state->state, &nsim_bpf_string_fops);
245         debugfs_create_bool("loaded", 0400, state->ddir, &state->is_loaded);
246
247         list_add_tail(&state->l, &nsim_dev->bpf_bound_progs);
248
249         prog->aux->offload->dev_priv = state;
250
251         return 0;
252 }
253
254 static int nsim_bpf_verifier_prep(struct bpf_prog *prog)
255 {
256         struct nsim_dev *nsim_dev =
257                         bpf_offload_dev_priv(prog->aux->offload->offdev);
258
259         if (!nsim_dev->bpf_bind_accept)
260                 return -EOPNOTSUPP;
261
262         return nsim_bpf_create_prog(nsim_dev, prog);
263 }
264
265 static int nsim_bpf_translate(struct bpf_prog *prog)
266 {
267         struct nsim_bpf_bound_prog *state = prog->aux->offload->dev_priv;
268
269         state->state = "xlated";
270         return 0;
271 }
272
273 static void nsim_bpf_destroy_prog(struct bpf_prog *prog)
274 {
275         struct nsim_bpf_bound_prog *state;
276
277         state = prog->aux->offload->dev_priv;
278         WARN(state->is_loaded,
279              "offload state destroyed while program still bound");
280         debugfs_remove_recursive(state->ddir);
281         list_del(&state->l);
282         kfree(state);
283 }
284
285 static const struct bpf_prog_offload_ops nsim_bpf_dev_ops = {
286         .insn_hook      = nsim_bpf_verify_insn,
287         .finalize       = nsim_bpf_finalize,
288         .prepare        = nsim_bpf_verifier_prep,
289         .translate      = nsim_bpf_translate,
290         .destroy        = nsim_bpf_destroy_prog,
291 };
292
293 static int nsim_setup_prog_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
294 {
295         if (bpf->prog && bpf->prog->aux->offload) {
296                 NSIM_EA(bpf->extack, "attempt to load offloaded prog to drv");
297                 return -EINVAL;
298         }
299         if (ns->netdev->mtu > NSIM_XDP_MAX_MTU) {
300                 NSIM_EA(bpf->extack, "MTU too large w/ XDP enabled");
301                 return -EINVAL;
302         }
303         return 0;
304 }
305
306 static int
307 nsim_setup_prog_hw_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
308 {
309         struct nsim_bpf_bound_prog *state;
310
311         if (!bpf->prog)
312                 return 0;
313
314         if (!bpf->prog->aux->offload) {
315                 NSIM_EA(bpf->extack, "xdpoffload of non-bound program");
316                 return -EINVAL;
317         }
318         if (!bpf_offload_dev_match(bpf->prog, ns->netdev)) {
319                 NSIM_EA(bpf->extack, "program bound to different dev");
320                 return -EINVAL;
321         }
322
323         state = bpf->prog->aux->offload->dev_priv;
324         if (WARN_ON(strcmp(state->state, "xlated"))) {
325                 NSIM_EA(bpf->extack, "offloading program in bad state");
326                 return -EINVAL;
327         }
328         return 0;
329 }
330
331 static bool
332 nsim_map_key_match(struct bpf_map *map, struct nsim_map_entry *e, void *key)
333 {
334         return e->key && !memcmp(key, e->key, map->key_size);
335 }
336
337 static int nsim_map_key_find(struct bpf_offloaded_map *offmap, void *key)
338 {
339         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
340         unsigned int i;
341
342         for (i = 0; i < ARRAY_SIZE(nmap->entry); i++)
343                 if (nsim_map_key_match(&offmap->map, &nmap->entry[i], key))
344                         return i;
345
346         return -ENOENT;
347 }
348
349 static int
350 nsim_map_alloc_elem(struct bpf_offloaded_map *offmap, unsigned int idx)
351 {
352         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
353
354         nmap->entry[idx].key = kmalloc(offmap->map.key_size, GFP_USER);
355         if (!nmap->entry[idx].key)
356                 return -ENOMEM;
357         nmap->entry[idx].value = kmalloc(offmap->map.value_size, GFP_USER);
358         if (!nmap->entry[idx].value) {
359                 kfree(nmap->entry[idx].key);
360                 nmap->entry[idx].key = NULL;
361                 return -ENOMEM;
362         }
363
364         return 0;
365 }
366
367 static int
368 nsim_map_get_next_key(struct bpf_offloaded_map *offmap,
369                       void *key, void *next_key)
370 {
371         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
372         int idx = -ENOENT;
373
374         mutex_lock(&nmap->mutex);
375
376         if (key)
377                 idx = nsim_map_key_find(offmap, key);
378         if (idx == -ENOENT)
379                 idx = 0;
380         else
381                 idx++;
382
383         for (; idx < ARRAY_SIZE(nmap->entry); idx++) {
384                 if (nmap->entry[idx].key) {
385                         memcpy(next_key, nmap->entry[idx].key,
386                                offmap->map.key_size);
387                         break;
388                 }
389         }
390
391         mutex_unlock(&nmap->mutex);
392
393         if (idx == ARRAY_SIZE(nmap->entry))
394                 return -ENOENT;
395         return 0;
396 }
397
398 static int
399 nsim_map_lookup_elem(struct bpf_offloaded_map *offmap, void *key, void *value)
400 {
401         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
402         int idx;
403
404         mutex_lock(&nmap->mutex);
405
406         idx = nsim_map_key_find(offmap, key);
407         if (idx >= 0)
408                 memcpy(value, nmap->entry[idx].value, offmap->map.value_size);
409
410         mutex_unlock(&nmap->mutex);
411
412         return idx < 0 ? idx : 0;
413 }
414
415 static int
416 nsim_map_update_elem(struct bpf_offloaded_map *offmap,
417                      void *key, void *value, u64 flags)
418 {
419         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
420         int idx, err = 0;
421
422         mutex_lock(&nmap->mutex);
423
424         idx = nsim_map_key_find(offmap, key);
425         if (idx < 0 && flags == BPF_EXIST) {
426                 err = idx;
427                 goto exit_unlock;
428         }
429         if (idx >= 0 && flags == BPF_NOEXIST) {
430                 err = -EEXIST;
431                 goto exit_unlock;
432         }
433
434         if (idx < 0) {
435                 for (idx = 0; idx < ARRAY_SIZE(nmap->entry); idx++)
436                         if (!nmap->entry[idx].key)
437                                 break;
438                 if (idx == ARRAY_SIZE(nmap->entry)) {
439                         err = -E2BIG;
440                         goto exit_unlock;
441                 }
442
443                 err = nsim_map_alloc_elem(offmap, idx);
444                 if (err)
445                         goto exit_unlock;
446         }
447
448         memcpy(nmap->entry[idx].key, key, offmap->map.key_size);
449         memcpy(nmap->entry[idx].value, value, offmap->map.value_size);
450 exit_unlock:
451         mutex_unlock(&nmap->mutex);
452
453         return err;
454 }
455
456 static int nsim_map_delete_elem(struct bpf_offloaded_map *offmap, void *key)
457 {
458         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
459         int idx;
460
461         if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY)
462                 return -EINVAL;
463
464         mutex_lock(&nmap->mutex);
465
466         idx = nsim_map_key_find(offmap, key);
467         if (idx >= 0) {
468                 kfree(nmap->entry[idx].key);
469                 kfree(nmap->entry[idx].value);
470                 memset(&nmap->entry[idx], 0, sizeof(nmap->entry[idx]));
471         }
472
473         mutex_unlock(&nmap->mutex);
474
475         return idx < 0 ? idx : 0;
476 }
477
478 static const struct bpf_map_dev_ops nsim_bpf_map_ops = {
479         .map_get_next_key       = nsim_map_get_next_key,
480         .map_lookup_elem        = nsim_map_lookup_elem,
481         .map_update_elem        = nsim_map_update_elem,
482         .map_delete_elem        = nsim_map_delete_elem,
483 };
484
485 static int
486 nsim_bpf_map_alloc(struct netdevsim *ns, struct bpf_offloaded_map *offmap)
487 {
488         struct nsim_bpf_bound_map *nmap;
489         int i, err;
490
491         if (WARN_ON(offmap->map.map_type != BPF_MAP_TYPE_ARRAY &&
492                     offmap->map.map_type != BPF_MAP_TYPE_HASH))
493                 return -EINVAL;
494         if (offmap->map.max_entries > NSIM_BPF_MAX_KEYS)
495                 return -ENOMEM;
496         if (offmap->map.map_flags)
497                 return -EINVAL;
498
499         nmap = kzalloc(sizeof(*nmap), GFP_USER);
500         if (!nmap)
501                 return -ENOMEM;
502
503         offmap->dev_priv = nmap;
504         nmap->ns = ns;
505         nmap->map = offmap;
506         mutex_init(&nmap->mutex);
507
508         if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY) {
509                 for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
510                         u32 *key;
511
512                         err = nsim_map_alloc_elem(offmap, i);
513                         if (err)
514                                 goto err_free;
515                         key = nmap->entry[i].key;
516                         *key = i;
517                 }
518         }
519
520         offmap->dev_ops = &nsim_bpf_map_ops;
521         list_add_tail(&nmap->l, &ns->nsim_dev->bpf_bound_maps);
522
523         return 0;
524
525 err_free:
526         while (--i >= 0) {
527                 kfree(nmap->entry[i].key);
528                 kfree(nmap->entry[i].value);
529         }
530         kfree(nmap);
531         return err;
532 }
533
534 static void nsim_bpf_map_free(struct bpf_offloaded_map *offmap)
535 {
536         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
537         unsigned int i;
538
539         for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
540                 kfree(nmap->entry[i].key);
541                 kfree(nmap->entry[i].value);
542         }
543         list_del_init(&nmap->l);
544         mutex_destroy(&nmap->mutex);
545         kfree(nmap);
546 }
547
548 int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
549 {
550         struct netdevsim *ns = netdev_priv(dev);
551         int err;
552
553         ASSERT_RTNL();
554
555         switch (bpf->command) {
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(nsim_dev->ddir_bpf_bound_progs))
591                 return PTR_ERR(nsim_dev->ddir_bpf_bound_progs);
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         nsim_dev->bpf_bind_verifier_accept = true;
604         debugfs_create_bool("bpf_bind_verifier_accept", 0600, nsim_dev->ddir,
605                             &nsim_dev->bpf_bind_verifier_accept);
606         return 0;
607 }
608
609 void nsim_bpf_dev_exit(struct nsim_dev *nsim_dev)
610 {
611         WARN_ON(!list_empty(&nsim_dev->bpf_bound_progs));
612         WARN_ON(!list_empty(&nsim_dev->bpf_bound_maps));
613         bpf_offload_dev_destroy(nsim_dev->bpf_dev);
614 }
615
616 int nsim_bpf_init(struct netdevsim *ns)
617 {
618         struct dentry *ddir = ns->nsim_dev_port->ddir;
619         int err;
620
621         err = bpf_offload_dev_netdev_register(ns->nsim_dev->bpf_dev,
622                                               ns->netdev);
623         if (err)
624                 return err;
625
626         debugfs_create_u32("bpf_offloaded_id", 0400, ddir,
627                            &ns->bpf_offloaded_id);
628
629         ns->bpf_tc_accept = true;
630         debugfs_create_bool("bpf_tc_accept", 0600, ddir,
631                             &ns->bpf_tc_accept);
632         debugfs_create_bool("bpf_tc_non_bound_accept", 0600, ddir,
633                             &ns->bpf_tc_non_bound_accept);
634         ns->bpf_xdpdrv_accept = true;
635         debugfs_create_bool("bpf_xdpdrv_accept", 0600, ddir,
636                             &ns->bpf_xdpdrv_accept);
637         ns->bpf_xdpoffload_accept = true;
638         debugfs_create_bool("bpf_xdpoffload_accept", 0600, ddir,
639                             &ns->bpf_xdpoffload_accept);
640
641         ns->bpf_map_accept = true;
642         debugfs_create_bool("bpf_map_accept", 0600, ddir,
643                             &ns->bpf_map_accept);
644
645         return 0;
646 }
647
648 void nsim_bpf_uninit(struct netdevsim *ns)
649 {
650         WARN_ON(ns->xdp.prog);
651         WARN_ON(ns->xdp_hw.prog);
652         WARN_ON(ns->bpf_offloaded);
653         bpf_offload_dev_netdev_unregister(ns->nsim_dev->bpf_dev, ns->netdev);
654 }