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
 29struct 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
 40struct 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
 51static 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}
 60DEFINE_SHOW_ATTRIBUTE(nsim_bpf_string);
 61
 62static int
 63nsim_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
 82static int nsim_bpf_finalize(struct bpf_verifier_env *env)
 83{
 84	return 0;
 85}
 86
 87static bool nsim_xdp_offload_active(struct netdevsim *ns)
 88{
 89	return ns->xdp_hw.prog;
 90}
 91
 92static 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
103static int
104nsim_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
118int 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
173int 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
180static 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
192static int
193nsim_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
218static 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
254static 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
265static 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
273static 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
285static 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
293static 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
306static int
307nsim_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
331static bool
332nsim_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
337static 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
349static int
350nsim_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,
355				       GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
356	if (!nmap->entry[idx].key)
357		return -ENOMEM;
358	nmap->entry[idx].value = kmalloc(offmap->map.value_size,
359					 GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
360	if (!nmap->entry[idx].value) {
361		kfree(nmap->entry[idx].key);
362		nmap->entry[idx].key = NULL;
363		return -ENOMEM;
364	}
365
366	return 0;
367}
368
369static int
370nsim_map_get_next_key(struct bpf_offloaded_map *offmap,
371		      void *key, void *next_key)
372{
373	struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
374	int idx = -ENOENT;
375
376	mutex_lock(&nmap->mutex);
377
378	if (key)
379		idx = nsim_map_key_find(offmap, key);
380	if (idx == -ENOENT)
381		idx = 0;
382	else
383		idx++;
384
385	for (; idx < ARRAY_SIZE(nmap->entry); idx++) {
386		if (nmap->entry[idx].key) {
387			memcpy(next_key, nmap->entry[idx].key,
388			       offmap->map.key_size);
389			break;
390		}
391	}
392
393	mutex_unlock(&nmap->mutex);
394
395	if (idx == ARRAY_SIZE(nmap->entry))
396		return -ENOENT;
397	return 0;
398}
399
400static int
401nsim_map_lookup_elem(struct bpf_offloaded_map *offmap, void *key, void *value)
402{
403	struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
404	int idx;
405
406	mutex_lock(&nmap->mutex);
407
408	idx = nsim_map_key_find(offmap, key);
409	if (idx >= 0)
410		memcpy(value, nmap->entry[idx].value, offmap->map.value_size);
411
412	mutex_unlock(&nmap->mutex);
413
414	return idx < 0 ? idx : 0;
415}
416
417static int
418nsim_map_update_elem(struct bpf_offloaded_map *offmap,
419		     void *key, void *value, u64 flags)
420{
421	struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
422	int idx, err = 0;
423
424	mutex_lock(&nmap->mutex);
425
426	idx = nsim_map_key_find(offmap, key);
427	if (idx < 0 && flags == BPF_EXIST) {
428		err = idx;
429		goto exit_unlock;
430	}
431	if (idx >= 0 && flags == BPF_NOEXIST) {
432		err = -EEXIST;
433		goto exit_unlock;
434	}
435
436	if (idx < 0) {
437		for (idx = 0; idx < ARRAY_SIZE(nmap->entry); idx++)
438			if (!nmap->entry[idx].key)
439				break;
440		if (idx == ARRAY_SIZE(nmap->entry)) {
441			err = -E2BIG;
442			goto exit_unlock;
443		}
444
445		err = nsim_map_alloc_elem(offmap, idx);
446		if (err)
447			goto exit_unlock;
448	}
449
450	memcpy(nmap->entry[idx].key, key, offmap->map.key_size);
451	memcpy(nmap->entry[idx].value, value, offmap->map.value_size);
452exit_unlock:
453	mutex_unlock(&nmap->mutex);
454
455	return err;
456}
457
458static int nsim_map_delete_elem(struct bpf_offloaded_map *offmap, void *key)
459{
460	struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
461	int idx;
462
463	if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY)
464		return -EINVAL;
465
466	mutex_lock(&nmap->mutex);
467
468	idx = nsim_map_key_find(offmap, key);
469	if (idx >= 0) {
470		kfree(nmap->entry[idx].key);
471		kfree(nmap->entry[idx].value);
472		memset(&nmap->entry[idx], 0, sizeof(nmap->entry[idx]));
473	}
474
475	mutex_unlock(&nmap->mutex);
476
477	return idx < 0 ? idx : 0;
478}
479
480static const struct bpf_map_dev_ops nsim_bpf_map_ops = {
481	.map_get_next_key	= nsim_map_get_next_key,
482	.map_lookup_elem	= nsim_map_lookup_elem,
483	.map_update_elem	= nsim_map_update_elem,
484	.map_delete_elem	= nsim_map_delete_elem,
485};
486
487static int
488nsim_bpf_map_alloc(struct netdevsim *ns, struct bpf_offloaded_map *offmap)
489{
490	struct nsim_bpf_bound_map *nmap;
491	int i, err;
492
493	if (WARN_ON(offmap->map.map_type != BPF_MAP_TYPE_ARRAY &&
494		    offmap->map.map_type != BPF_MAP_TYPE_HASH))
495		return -EINVAL;
496	if (offmap->map.max_entries > NSIM_BPF_MAX_KEYS)
497		return -ENOMEM;
498	if (offmap->map.map_flags)
499		return -EINVAL;
500
501	nmap = kzalloc(sizeof(*nmap), GFP_KERNEL_ACCOUNT);
502	if (!nmap)
503		return -ENOMEM;
504
505	offmap->dev_priv = nmap;
506	nmap->ns = ns;
507	nmap->map = offmap;
508	mutex_init(&nmap->mutex);
509
510	if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY) {
511		for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
512			u32 *key;
513
514			err = nsim_map_alloc_elem(offmap, i);
515			if (err)
516				goto err_free;
517			key = nmap->entry[i].key;
518			*key = i;
519			memset(nmap->entry[i].value, 0, offmap->map.value_size);
520		}
521	}
522
523	offmap->dev_ops = &nsim_bpf_map_ops;
524	list_add_tail(&nmap->l, &ns->nsim_dev->bpf_bound_maps);
525
526	return 0;
527
528err_free:
529	while (--i >= 0) {
530		kfree(nmap->entry[i].key);
531		kfree(nmap->entry[i].value);
532	}
533	kfree(nmap);
534	return err;
535}
536
537static void nsim_bpf_map_free(struct bpf_offloaded_map *offmap)
538{
539	struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
540	unsigned int i;
541
542	for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
543		kfree(nmap->entry[i].key);
544		kfree(nmap->entry[i].value);
545	}
546	list_del_init(&nmap->l);
547	mutex_destroy(&nmap->mutex);
548	kfree(nmap);
549}
550
551int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
552{
553	struct netdevsim *ns = netdev_priv(dev);
554	int err;
555
556	ASSERT_RTNL();
557
558	switch (bpf->command) {
559	case XDP_SETUP_PROG:
560		err = nsim_setup_prog_checks(ns, bpf);
561		if (err)
562			return err;
563
564		return nsim_xdp_set_prog(ns, bpf, &ns->xdp);
565	case XDP_SETUP_PROG_HW:
566		err = nsim_setup_prog_hw_checks(ns, bpf);
567		if (err)
568			return err;
569
570		return nsim_xdp_set_prog(ns, bpf, &ns->xdp_hw);
571	case BPF_OFFLOAD_MAP_ALLOC:
572		if (!ns->bpf_map_accept)
573			return -EOPNOTSUPP;
574
575		return nsim_bpf_map_alloc(ns, bpf->offmap);
576	case BPF_OFFLOAD_MAP_FREE:
577		nsim_bpf_map_free(bpf->offmap);
578		return 0;
579	default:
580		return -EINVAL;
581	}
582}
583
584int nsim_bpf_dev_init(struct nsim_dev *nsim_dev)
585{
586	int err;
587
588	INIT_LIST_HEAD(&nsim_dev->bpf_bound_progs);
589	INIT_LIST_HEAD(&nsim_dev->bpf_bound_maps);
590
591	nsim_dev->ddir_bpf_bound_progs = debugfs_create_dir("bpf_bound_progs",
592							    nsim_dev->ddir);
593	if (IS_ERR(nsim_dev->ddir_bpf_bound_progs))
594		return PTR_ERR(nsim_dev->ddir_bpf_bound_progs);
595
596	nsim_dev->bpf_dev = bpf_offload_dev_create(&nsim_bpf_dev_ops, nsim_dev);
597	err = PTR_ERR_OR_ZERO(nsim_dev->bpf_dev);
598	if (err)
599		return err;
600
601	nsim_dev->bpf_bind_accept = true;
602	debugfs_create_bool("bpf_bind_accept", 0600, nsim_dev->ddir,
603			    &nsim_dev->bpf_bind_accept);
604	debugfs_create_u32("bpf_bind_verifier_delay", 0600, nsim_dev->ddir,
605			   &nsim_dev->bpf_bind_verifier_delay);
606	nsim_dev->bpf_bind_verifier_accept = true;
607	debugfs_create_bool("bpf_bind_verifier_accept", 0600, nsim_dev->ddir,
608			    &nsim_dev->bpf_bind_verifier_accept);
609	return 0;
610}
611
612void nsim_bpf_dev_exit(struct nsim_dev *nsim_dev)
613{
614	WARN_ON(!list_empty(&nsim_dev->bpf_bound_progs));
615	WARN_ON(!list_empty(&nsim_dev->bpf_bound_maps));
616	bpf_offload_dev_destroy(nsim_dev->bpf_dev);
617}
618
619int nsim_bpf_init(struct netdevsim *ns)
620{
621	struct dentry *ddir = ns->nsim_dev_port->ddir;
622	int err;
623
624	err = bpf_offload_dev_netdev_register(ns->nsim_dev->bpf_dev,
625					      ns->netdev);
626	if (err)
627		return err;
628
629	debugfs_create_u32("bpf_offloaded_id", 0400, ddir,
630			   &ns->bpf_offloaded_id);
631
632	ns->bpf_tc_accept = true;
633	debugfs_create_bool("bpf_tc_accept", 0600, ddir,
634			    &ns->bpf_tc_accept);
635	debugfs_create_bool("bpf_tc_non_bound_accept", 0600, ddir,
636			    &ns->bpf_tc_non_bound_accept);
637	ns->bpf_xdpdrv_accept = true;
638	debugfs_create_bool("bpf_xdpdrv_accept", 0600, ddir,
639			    &ns->bpf_xdpdrv_accept);
640	ns->bpf_xdpoffload_accept = true;
641	debugfs_create_bool("bpf_xdpoffload_accept", 0600, ddir,
642			    &ns->bpf_xdpoffload_accept);
643
644	ns->bpf_map_accept = true;
645	debugfs_create_bool("bpf_map_accept", 0600, ddir,
646			    &ns->bpf_map_accept);
647
648	return 0;
649}
650
651void nsim_bpf_uninit(struct netdevsim *ns)
652{
653	WARN_ON(ns->xdp.prog);
654	WARN_ON(ns->xdp_hw.prog);
655	WARN_ON(ns->bpf_offloaded);
656	bpf_offload_dev_netdev_unregister(ns->nsim_dev->bpf_dev, ns->netdev);
657}