Merge tag 'drm-for-v4.16-part2-fixes' of git://people.freedesktop.org/~airlied/linux
[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 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_prog_mode == XDP_ATTACHED_HW;
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 nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
199 {
200         int err;
201
202         if (ns->xdp_prog && (bpf->flags ^ ns->xdp_flags) & XDP_FLAGS_MODES) {
203                 NSIM_EA(bpf->extack, "program loaded with different flags");
204                 return -EBUSY;
205         }
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         if (ns->xdp_prog)
223                 bpf_prog_put(ns->xdp_prog);
224
225         ns->xdp_prog = bpf->prog;
226         ns->xdp_flags = bpf->flags;
227
228         if (!bpf->prog)
229                 ns->xdp_prog_mode = XDP_ATTACHED_NONE;
230         else if (bpf->command == XDP_SETUP_PROG)
231                 ns->xdp_prog_mode = XDP_ATTACHED_DRV;
232         else
233                 ns->xdp_prog_mode = XDP_ATTACHED_HW;
234
235         return 0;
236 }
237
238 static int nsim_bpf_create_prog(struct netdevsim *ns, struct bpf_prog *prog)
239 {
240         struct nsim_bpf_bound_prog *state;
241         char name[16];
242
243         state = kzalloc(sizeof(*state), GFP_KERNEL);
244         if (!state)
245                 return -ENOMEM;
246
247         state->ns = ns;
248         state->prog = prog;
249         state->state = "verify";
250
251         /* Program id is not populated yet when we create the state. */
252         sprintf(name, "%u", ns->prog_id_gen++);
253         state->ddir = debugfs_create_dir(name, ns->ddir_bpf_bound_progs);
254         if (IS_ERR_OR_NULL(state->ddir)) {
255                 kfree(state);
256                 return -ENOMEM;
257         }
258
259         debugfs_create_u32("id", 0400, state->ddir, &prog->aux->id);
260         debugfs_create_file("state", 0400, state->ddir,
261                             &state->state, &nsim_bpf_string_fops);
262         debugfs_create_bool("loaded", 0400, state->ddir, &state->is_loaded);
263
264         list_add_tail(&state->l, &ns->bpf_bound_progs);
265
266         prog->aux->offload->dev_priv = state;
267
268         return 0;
269 }
270
271 static void nsim_bpf_destroy_prog(struct bpf_prog *prog)
272 {
273         struct nsim_bpf_bound_prog *state;
274
275         state = prog->aux->offload->dev_priv;
276         WARN(state->is_loaded,
277              "offload state destroyed while program still bound");
278         debugfs_remove_recursive(state->ddir);
279         list_del(&state->l);
280         kfree(state);
281 }
282
283 static int nsim_setup_prog_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
284 {
285         if (bpf->prog && bpf->prog->aux->offload) {
286                 NSIM_EA(bpf->extack, "attempt to load offloaded prog to drv");
287                 return -EINVAL;
288         }
289         if (ns->netdev->mtu > NSIM_XDP_MAX_MTU) {
290                 NSIM_EA(bpf->extack, "MTU too large w/ XDP enabled");
291                 return -EINVAL;
292         }
293         if (nsim_xdp_offload_active(ns)) {
294                 NSIM_EA(bpf->extack, "xdp offload active, can't load drv prog");
295                 return -EBUSY;
296         }
297         return 0;
298 }
299
300 static int
301 nsim_setup_prog_hw_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
302 {
303         struct nsim_bpf_bound_prog *state;
304
305         if (!bpf->prog)
306                 return 0;
307
308         if (!bpf->prog->aux->offload) {
309                 NSIM_EA(bpf->extack, "xdpoffload of non-bound program");
310                 return -EINVAL;
311         }
312         if (bpf->prog->aux->offload->netdev != ns->netdev) {
313                 NSIM_EA(bpf->extack, "program bound to different dev");
314                 return -EINVAL;
315         }
316
317         state = bpf->prog->aux->offload->dev_priv;
318         if (WARN_ON(strcmp(state->state, "xlated"))) {
319                 NSIM_EA(bpf->extack, "offloading program in bad state");
320                 return -EINVAL;
321         }
322         return 0;
323 }
324
325 static bool
326 nsim_map_key_match(struct bpf_map *map, struct nsim_map_entry *e, void *key)
327 {
328         return e->key && !memcmp(key, e->key, map->key_size);
329 }
330
331 static int nsim_map_key_find(struct bpf_offloaded_map *offmap, void *key)
332 {
333         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
334         unsigned int i;
335
336         for (i = 0; i < ARRAY_SIZE(nmap->entry); i++)
337                 if (nsim_map_key_match(&offmap->map, &nmap->entry[i], key))
338                         return i;
339
340         return -ENOENT;
341 }
342
343 static int
344 nsim_map_alloc_elem(struct bpf_offloaded_map *offmap, unsigned int idx)
345 {
346         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
347
348         nmap->entry[idx].key = kmalloc(offmap->map.key_size, GFP_USER);
349         if (!nmap->entry[idx].key)
350                 return -ENOMEM;
351         nmap->entry[idx].value = kmalloc(offmap->map.value_size, GFP_USER);
352         if (!nmap->entry[idx].value) {
353                 kfree(nmap->entry[idx].key);
354                 nmap->entry[idx].key = NULL;
355                 return -ENOMEM;
356         }
357
358         return 0;
359 }
360
361 static int
362 nsim_map_get_next_key(struct bpf_offloaded_map *offmap,
363                       void *key, void *next_key)
364 {
365         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
366         int idx = -ENOENT;
367
368         mutex_lock(&nmap->mutex);
369
370         if (key)
371                 idx = nsim_map_key_find(offmap, key);
372         if (idx == -ENOENT)
373                 idx = 0;
374         else
375                 idx++;
376
377         for (; idx < ARRAY_SIZE(nmap->entry); idx++) {
378                 if (nmap->entry[idx].key) {
379                         memcpy(next_key, nmap->entry[idx].key,
380                                offmap->map.key_size);
381                         break;
382                 }
383         }
384
385         mutex_unlock(&nmap->mutex);
386
387         if (idx == ARRAY_SIZE(nmap->entry))
388                 return -ENOENT;
389         return 0;
390 }
391
392 static int
393 nsim_map_lookup_elem(struct bpf_offloaded_map *offmap, void *key, void *value)
394 {
395         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
396         int idx;
397
398         mutex_lock(&nmap->mutex);
399
400         idx = nsim_map_key_find(offmap, key);
401         if (idx >= 0)
402                 memcpy(value, nmap->entry[idx].value, offmap->map.value_size);
403
404         mutex_unlock(&nmap->mutex);
405
406         return idx < 0 ? idx : 0;
407 }
408
409 static int
410 nsim_map_update_elem(struct bpf_offloaded_map *offmap,
411                      void *key, void *value, u64 flags)
412 {
413         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
414         int idx, err = 0;
415
416         mutex_lock(&nmap->mutex);
417
418         idx = nsim_map_key_find(offmap, key);
419         if (idx < 0 && flags == BPF_EXIST) {
420                 err = idx;
421                 goto exit_unlock;
422         }
423         if (idx >= 0 && flags == BPF_NOEXIST) {
424                 err = -EEXIST;
425                 goto exit_unlock;
426         }
427
428         if (idx < 0) {
429                 for (idx = 0; idx < ARRAY_SIZE(nmap->entry); idx++)
430                         if (!nmap->entry[idx].key)
431                                 break;
432                 if (idx == ARRAY_SIZE(nmap->entry)) {
433                         err = -E2BIG;
434                         goto exit_unlock;
435                 }
436
437                 err = nsim_map_alloc_elem(offmap, idx);
438                 if (err)
439                         goto exit_unlock;
440         }
441
442         memcpy(nmap->entry[idx].key, key, offmap->map.key_size);
443         memcpy(nmap->entry[idx].value, value, offmap->map.value_size);
444 exit_unlock:
445         mutex_unlock(&nmap->mutex);
446
447         return err;
448 }
449
450 static int nsim_map_delete_elem(struct bpf_offloaded_map *offmap, void *key)
451 {
452         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
453         int idx;
454
455         if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY)
456                 return -EINVAL;
457
458         mutex_lock(&nmap->mutex);
459
460         idx = nsim_map_key_find(offmap, key);
461         if (idx >= 0) {
462                 kfree(nmap->entry[idx].key);
463                 kfree(nmap->entry[idx].value);
464                 memset(&nmap->entry[idx], 0, sizeof(nmap->entry[idx]));
465         }
466
467         mutex_unlock(&nmap->mutex);
468
469         return idx < 0 ? idx : 0;
470 }
471
472 static const struct bpf_map_dev_ops nsim_bpf_map_ops = {
473         .map_get_next_key       = nsim_map_get_next_key,
474         .map_lookup_elem        = nsim_map_lookup_elem,
475         .map_update_elem        = nsim_map_update_elem,
476         .map_delete_elem        = nsim_map_delete_elem,
477 };
478
479 static int
480 nsim_bpf_map_alloc(struct netdevsim *ns, struct bpf_offloaded_map *offmap)
481 {
482         struct nsim_bpf_bound_map *nmap;
483         int i, err;
484
485         if (WARN_ON(offmap->map.map_type != BPF_MAP_TYPE_ARRAY &&
486                     offmap->map.map_type != BPF_MAP_TYPE_HASH))
487                 return -EINVAL;
488         if (offmap->map.max_entries > NSIM_BPF_MAX_KEYS)
489                 return -ENOMEM;
490         if (offmap->map.map_flags)
491                 return -EINVAL;
492
493         nmap = kzalloc(sizeof(*nmap), GFP_USER);
494         if (!nmap)
495                 return -ENOMEM;
496
497         offmap->dev_priv = nmap;
498         nmap->ns = ns;
499         nmap->map = offmap;
500         mutex_init(&nmap->mutex);
501
502         if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY) {
503                 for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
504                         u32 *key;
505
506                         err = nsim_map_alloc_elem(offmap, i);
507                         if (err)
508                                 goto err_free;
509                         key = nmap->entry[i].key;
510                         *key = i;
511                 }
512         }
513
514         offmap->dev_ops = &nsim_bpf_map_ops;
515         list_add_tail(&nmap->l, &ns->bpf_bound_maps);
516
517         return 0;
518
519 err_free:
520         while (--i >= 0) {
521                 kfree(nmap->entry[i].key);
522                 kfree(nmap->entry[i].value);
523         }
524         kfree(nmap);
525         return err;
526 }
527
528 static void nsim_bpf_map_free(struct bpf_offloaded_map *offmap)
529 {
530         struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
531         unsigned int i;
532
533         for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
534                 kfree(nmap->entry[i].key);
535                 kfree(nmap->entry[i].value);
536         }
537         list_del_init(&nmap->l);
538         mutex_destroy(&nmap->mutex);
539         kfree(nmap);
540 }
541
542 int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
543 {
544         struct netdevsim *ns = netdev_priv(dev);
545         struct nsim_bpf_bound_prog *state;
546         int err;
547
548         ASSERT_RTNL();
549
550         switch (bpf->command) {
551         case BPF_OFFLOAD_VERIFIER_PREP:
552                 if (!ns->bpf_bind_accept)
553                         return -EOPNOTSUPP;
554
555                 err = nsim_bpf_create_prog(ns, bpf->verifier.prog);
556                 if (err)
557                         return err;
558
559                 bpf->verifier.ops = &nsim_bpf_analyzer_ops;
560                 return 0;
561         case BPF_OFFLOAD_TRANSLATE:
562                 state = bpf->offload.prog->aux->offload->dev_priv;
563
564                 state->state = "xlated";
565                 return 0;
566         case BPF_OFFLOAD_DESTROY:
567                 nsim_bpf_destroy_prog(bpf->offload.prog);
568                 return 0;
569         case XDP_QUERY_PROG:
570                 bpf->prog_attached = ns->xdp_prog_mode;
571                 bpf->prog_id = ns->xdp_prog ? ns->xdp_prog->aux->id : 0;
572                 bpf->prog_flags = ns->xdp_prog ? ns->xdp_flags : 0;
573                 return 0;
574         case XDP_SETUP_PROG:
575                 err = nsim_setup_prog_checks(ns, bpf);
576                 if (err)
577                         return err;
578
579                 return nsim_xdp_set_prog(ns, bpf);
580         case XDP_SETUP_PROG_HW:
581                 err = nsim_setup_prog_hw_checks(ns, bpf);
582                 if (err)
583                         return err;
584
585                 return nsim_xdp_set_prog(ns, bpf);
586         case BPF_OFFLOAD_MAP_ALLOC:
587                 if (!ns->bpf_map_accept)
588                         return -EOPNOTSUPP;
589
590                 return nsim_bpf_map_alloc(ns, bpf->offmap);
591         case BPF_OFFLOAD_MAP_FREE:
592                 nsim_bpf_map_free(bpf->offmap);
593                 return 0;
594         default:
595                 return -EINVAL;
596         }
597 }
598
599 int nsim_bpf_init(struct netdevsim *ns)
600 {
601         INIT_LIST_HEAD(&ns->bpf_bound_progs);
602         INIT_LIST_HEAD(&ns->bpf_bound_maps);
603
604         debugfs_create_u32("bpf_offloaded_id", 0400, ns->ddir,
605                            &ns->bpf_offloaded_id);
606
607         ns->bpf_bind_accept = true;
608         debugfs_create_bool("bpf_bind_accept", 0600, ns->ddir,
609                             &ns->bpf_bind_accept);
610         debugfs_create_u32("bpf_bind_verifier_delay", 0600, ns->ddir,
611                            &ns->bpf_bind_verifier_delay);
612         ns->ddir_bpf_bound_progs =
613                 debugfs_create_dir("bpf_bound_progs", ns->ddir);
614         if (IS_ERR_OR_NULL(ns->ddir_bpf_bound_progs))
615                 return -ENOMEM;
616
617         ns->bpf_tc_accept = true;
618         debugfs_create_bool("bpf_tc_accept", 0600, ns->ddir,
619                             &ns->bpf_tc_accept);
620         debugfs_create_bool("bpf_tc_non_bound_accept", 0600, ns->ddir,
621                             &ns->bpf_tc_non_bound_accept);
622         ns->bpf_xdpdrv_accept = true;
623         debugfs_create_bool("bpf_xdpdrv_accept", 0600, ns->ddir,
624                             &ns->bpf_xdpdrv_accept);
625         ns->bpf_xdpoffload_accept = true;
626         debugfs_create_bool("bpf_xdpoffload_accept", 0600, ns->ddir,
627                             &ns->bpf_xdpoffload_accept);
628
629         ns->bpf_map_accept = true;
630         debugfs_create_bool("bpf_map_accept", 0600, ns->ddir,
631                             &ns->bpf_map_accept);
632
633         return 0;
634 }
635
636 void nsim_bpf_uninit(struct netdevsim *ns)
637 {
638         WARN_ON(!list_empty(&ns->bpf_bound_progs));
639         WARN_ON(!list_empty(&ns->bpf_bound_maps));
640         WARN_ON(ns->xdp_prog);
641         WARN_ON(ns->bpf_offloaded);
642 }