Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
/*
 * Berkeley Packet Filter based traffic classifier
 *
 * Might be used to classify traffic through flexible, user-defined and
 * possibly JIT-ed BPF filters for traffic control as an alternative to
 * ematches.
 *
 * (C) 2013 Daniel Borkmann <dborkman@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/filter.h>
#include <linux/bpf.h>
#include <linux/idr.h>

#include <net/rtnetlink.h>
#include <net/pkt_cls.h>
#include <net/sock.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
MODULE_DESCRIPTION("TC BPF based classifier");

#define CLS_BPF_NAME_LEN	256
#define CLS_BPF_SUPPORTED_GEN_FLAGS		\
	(TCA_CLS_FLAGS_SKIP_HW | TCA_CLS_FLAGS_SKIP_SW)

struct cls_bpf_head {
	struct list_head plist;
	struct idr handle_idr;
	struct rcu_head rcu;
};

struct cls_bpf_prog {
	struct bpf_prog *filter;
	struct list_head link;
	struct tcf_result res;
	bool exts_integrated;
	u32 gen_flags;
	unsigned int in_hw_count;
	struct tcf_exts exts;
	u32 handle;
	u16 bpf_num_ops;
	struct sock_filter *bpf_ops;
	const char *bpf_name;
	struct tcf_proto *tp;
	struct rcu_work rwork;
};

static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
	[TCA_BPF_CLASSID]	= { .type = NLA_U32 },
	[TCA_BPF_FLAGS]		= { .type = NLA_U32 },
	[TCA_BPF_FLAGS_GEN]	= { .type = NLA_U32 },
	[TCA_BPF_FD]		= { .type = NLA_U32 },
	[TCA_BPF_NAME]		= { .type = NLA_NUL_STRING,
				    .len = CLS_BPF_NAME_LEN },
	[TCA_BPF_OPS_LEN]	= { .type = NLA_U16 },
	[TCA_BPF_OPS]		= { .type = NLA_BINARY,
				    .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
};

static int cls_bpf_exec_opcode(int code)
{
	switch (code) {
	case TC_ACT_OK:
	case TC_ACT_SHOT:
	case TC_ACT_STOLEN:
	case TC_ACT_TRAP:
	case TC_ACT_REDIRECT:
	case TC_ACT_UNSPEC:
		return code;
	default:
		return TC_ACT_UNSPEC;
	}
}

static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
			    struct tcf_result *res)
{
	struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
	bool at_ingress = skb_at_tc_ingress(skb);
	struct cls_bpf_prog *prog;
	int ret = -1;

	/* Needed here for accessing maps. */
	rcu_read_lock();
	list_for_each_entry_rcu(prog, &head->plist, link) {
		int filter_res;

		qdisc_skb_cb(skb)->tc_classid = prog->res.classid;

		if (tc_skip_sw(prog->gen_flags)) {
			filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0;
		} else if (at_ingress) {
			/* It is safe to push/pull even if skb_shared() */
			__skb_push(skb, skb->mac_len);
			bpf_compute_data_pointers(skb);
			filter_res = BPF_PROG_RUN(prog->filter, skb);
			__skb_pull(skb, skb->mac_len);
		} else {
			bpf_compute_data_pointers(skb);
			filter_res = BPF_PROG_RUN(prog->filter, skb);
		}

		if (prog->exts_integrated) {
			res->class   = 0;
			res->classid = TC_H_MAJ(prog->res.classid) |
				       qdisc_skb_cb(skb)->tc_classid;

			ret = cls_bpf_exec_opcode(filter_res);
			if (ret == TC_ACT_UNSPEC)
				continue;
			break;
		}

		if (filter_res == 0)
			continue;
		if (filter_res != -1) {
			res->class   = 0;
			res->classid = filter_res;
		} else {
			*res = prog->res;
		}

		ret = tcf_exts_exec(skb, &prog->exts, res);
		if (ret < 0)
			continue;

		break;
	}
	rcu_read_unlock();

	return ret;
}

static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
{
	return !prog->bpf_ops;
}

static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
			       struct cls_bpf_prog *oldprog,
			       struct netlink_ext_ack *extack)
{
	struct tcf_block *block = tp->chain->block;
	struct tc_cls_bpf_offload cls_bpf = {};
	struct cls_bpf_prog *obj;
	bool skip_sw;
	int err;

	skip_sw = prog && tc_skip_sw(prog->gen_flags);
	obj = prog ?: oldprog;

	tc_cls_common_offload_init(&cls_bpf.common, tp, obj->gen_flags,
				   extack);
	cls_bpf.command = TC_CLSBPF_OFFLOAD;
	cls_bpf.exts = &obj->exts;
	cls_bpf.prog = prog ? prog->filter : NULL;
	cls_bpf.oldprog = oldprog ? oldprog->filter : NULL;
	cls_bpf.name = obj->bpf_name;
	cls_bpf.exts_integrated = obj->exts_integrated;

	if (oldprog)
		tcf_block_offload_dec(block, &oldprog->gen_flags);

	err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, skip_sw);
	if (prog) {
		if (err < 0) {
			cls_bpf_offload_cmd(tp, oldprog, prog, extack);
			return err;
		} else if (err > 0) {
			prog->in_hw_count = err;
			tcf_block_offload_inc(block, &prog->gen_flags);
		}
	}

	if (prog && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
		return -EINVAL;

	return 0;
}

static u32 cls_bpf_flags(u32 flags)
{
	return flags & CLS_BPF_SUPPORTED_GEN_FLAGS;
}

static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
			   struct cls_bpf_prog *oldprog,
			   struct netlink_ext_ack *extack)
{
	if (prog && oldprog &&
	    cls_bpf_flags(prog->gen_flags) !=
	    cls_bpf_flags(oldprog->gen_flags))
		return -EINVAL;

	if (prog && tc_skip_hw(prog->gen_flags))
		prog = NULL;
	if (oldprog && tc_skip_hw(oldprog->gen_flags))
		oldprog = NULL;
	if (!prog && !oldprog)
		return 0;

	return cls_bpf_offload_cmd(tp, prog, oldprog, extack);
}

static void cls_bpf_stop_offload(struct tcf_proto *tp,
				 struct cls_bpf_prog *prog,
				 struct netlink_ext_ack *extack)
{
	int err;

	err = cls_bpf_offload_cmd(tp, NULL, prog, extack);
	if (err)
		pr_err("Stopping hardware offload failed: %d\n", err);
}

static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
					 struct cls_bpf_prog *prog)
{
	struct tcf_block *block = tp->chain->block;
	struct tc_cls_bpf_offload cls_bpf = {};

	tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags, NULL);
	cls_bpf.command = TC_CLSBPF_STATS;
	cls_bpf.exts = &prog->exts;
	cls_bpf.prog = prog->filter;
	cls_bpf.name = prog->bpf_name;
	cls_bpf.exts_integrated = prog->exts_integrated;

	tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, false);
}

static int cls_bpf_init(struct tcf_proto *tp)
{
	struct cls_bpf_head *head;

	head = kzalloc(sizeof(*head), GFP_KERNEL);
	if (head == NULL)
		return -ENOBUFS;

	INIT_LIST_HEAD_RCU(&head->plist);
	idr_init(&head->handle_idr);
	rcu_assign_pointer(tp->root, head);

	return 0;
}

static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
{
	if (cls_bpf_is_ebpf(prog))
		bpf_prog_put(prog->filter);
	else
		bpf_prog_destroy(prog->filter);

	kfree(prog->bpf_name);
	kfree(prog->bpf_ops);
}

static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
{
	tcf_exts_destroy(&prog->exts);
	tcf_exts_put_net(&prog->exts);

	cls_bpf_free_parms(prog);
	kfree(prog);
}

static void cls_bpf_delete_prog_work(struct work_struct *work)
{
	struct cls_bpf_prog *prog = container_of(to_rcu_work(work),
						 struct cls_bpf_prog,
						 rwork);
	rtnl_lock();
	__cls_bpf_delete_prog(prog);
	rtnl_unlock();
}

static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
			     struct netlink_ext_ack *extack)
{
	struct cls_bpf_head *head = rtnl_dereference(tp->root);

	idr_remove(&head->handle_idr, prog->handle);
	cls_bpf_stop_offload(tp, prog, extack);
	list_del_rcu(&prog->link);
	tcf_unbind_filter(tp, &prog->res);
	if (tcf_exts_get_net(&prog->exts))
		tcf_queue_work(&prog->rwork, cls_bpf_delete_prog_work);
	else
		__cls_bpf_delete_prog(prog);
}

static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last,
			  struct netlink_ext_ack *extack)
{
	struct cls_bpf_head *head = rtnl_dereference(tp->root);

	__cls_bpf_delete(tp, arg, extack);
	*last = list_empty(&head->plist);
	return 0;
}

static void cls_bpf_destroy(struct tcf_proto *tp,
			    struct netlink_ext_ack *extack)
{
	struct cls_bpf_head *head = rtnl_dereference(tp->root);
	struct cls_bpf_prog *prog, *tmp;

	list_for_each_entry_safe(prog, tmp, &head->plist, link)
		__cls_bpf_delete(tp, prog, extack);

	idr_destroy(&head->handle_idr);
	kfree_rcu(head, rcu);
}

static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
{
	struct cls_bpf_head *head = rtnl_dereference(tp->root);
	struct cls_bpf_prog *prog;

	list_for_each_entry(prog, &head->plist, link) {
		if (prog->handle == handle)
			return prog;
	}

	return NULL;
}

static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
{
	struct sock_filter *bpf_ops;
	struct sock_fprog_kern fprog_tmp;
	struct bpf_prog *fp;
	u16 bpf_size, bpf_num_ops;
	int ret;

	bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
	if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
		return -EINVAL;

	bpf_size = bpf_num_ops * sizeof(*bpf_ops);
	if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
		return -EINVAL;

	bpf_ops = kmemdup(nla_data(tb[TCA_BPF_OPS]), bpf_size, GFP_KERNEL);
	if (bpf_ops == NULL)
		return -ENOMEM;

	fprog_tmp.len = bpf_num_ops;
	fprog_tmp.filter = bpf_ops;

	ret = bpf_prog_create(&fp, &fprog_tmp);
	if (ret < 0) {
		kfree(bpf_ops);
		return ret;
	}

	prog->bpf_ops = bpf_ops;
	prog->bpf_num_ops = bpf_num_ops;
	prog->bpf_name = NULL;
	prog->filter = fp;

	return 0;
}

static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
				 u32 gen_flags, const struct tcf_proto *tp)
{
	struct bpf_prog *fp;
	char *name = NULL;
	bool skip_sw;
	u32 bpf_fd;

	bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
	skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW;

	fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw);
	if (IS_ERR(fp))
		return PTR_ERR(fp);

	if (tb[TCA_BPF_NAME]) {
		name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
		if (!name) {
			bpf_prog_put(fp);
			return -ENOMEM;
		}
	}

	prog->bpf_ops = NULL;
	prog->bpf_name = name;
	prog->filter = fp;

	if (fp->dst_needed)
		tcf_block_netif_keep_dst(tp->chain->block);

	return 0;
}

static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
			     struct cls_bpf_prog *prog, unsigned long base,
			     struct nlattr **tb, struct nlattr *est, bool ovr,
			     struct netlink_ext_ack *extack)
{
	bool is_bpf, is_ebpf, have_exts = false;
	u32 gen_flags = 0;
	int ret;

	is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
	is_ebpf = tb[TCA_BPF_FD];
	if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
		return -EINVAL;

	ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr, extack);
	if (ret < 0)
		return ret;

	if (tb[TCA_BPF_FLAGS]) {
		u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);

		if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
			return -EINVAL;

		have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
	}
	if (tb[TCA_BPF_FLAGS_GEN]) {
		gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
		if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
		    !tc_flags_valid(gen_flags))
			return -EINVAL;
	}

	prog->exts_integrated = have_exts;
	prog->gen_flags = gen_flags;

	ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
		       cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
	if (ret < 0)
		return ret;

	if (tb[TCA_BPF_CLASSID]) {
		prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
		tcf_bind_filter(tp, &prog->res, base);
	}

	return 0;
}

static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
			  struct tcf_proto *tp, unsigned long base,
			  u32 handle, struct nlattr **tca,
			  void **arg, bool ovr, struct netlink_ext_ack *extack)
{
	struct cls_bpf_head *head = rtnl_dereference(tp->root);
	struct cls_bpf_prog *oldprog = *arg;
	struct nlattr *tb[TCA_BPF_MAX + 1];
	struct cls_bpf_prog *prog;
	int ret;

	if (tca[TCA_OPTIONS] == NULL)
		return -EINVAL;

	ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
			       NULL);
	if (ret < 0)
		return ret;

	prog = kzalloc(sizeof(*prog), GFP_KERNEL);
	if (!prog)
		return -ENOBUFS;

	ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
	if (ret < 0)
		goto errout;

	if (oldprog) {
		if (handle && oldprog->handle != handle) {
			ret = -EINVAL;
			goto errout;
		}
	}

	if (handle == 0) {
		handle = 1;
		ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
				    INT_MAX, GFP_KERNEL);
	} else if (!oldprog) {
		ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
				    handle, GFP_KERNEL);
	}

	if (ret)
		goto errout;
	prog->handle = handle;

	ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr,
				extack);
	if (ret < 0)
		goto errout_idr;

	ret = cls_bpf_offload(tp, prog, oldprog, extack);
	if (ret)
		goto errout_parms;

	if (!tc_in_hw(prog->gen_flags))
		prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;

	if (oldprog) {
		idr_replace(&head->handle_idr, prog, handle);
		list_replace_rcu(&oldprog->link, &prog->link);
		tcf_unbind_filter(tp, &oldprog->res);
		tcf_exts_get_net(&oldprog->exts);
		tcf_queue_work(&oldprog->rwork, cls_bpf_delete_prog_work);
	} else {
		list_add_rcu(&prog->link, &head->plist);
	}

	*arg = prog;
	return 0;

errout_parms:
	cls_bpf_free_parms(prog);
errout_idr:
	if (!oldprog)
		idr_remove(&head->handle_idr, prog->handle);
errout:
	tcf_exts_destroy(&prog->exts);
	kfree(prog);
	return ret;
}

static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
				 struct sk_buff *skb)
{
	struct nlattr *nla;

	if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
		return -EMSGSIZE;

	nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
			  sizeof(struct sock_filter));
	if (nla == NULL)
		return -EMSGSIZE;

	memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));

	return 0;
}

static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
				  struct sk_buff *skb)
{
	struct nlattr *nla;

	if (prog->bpf_name &&
	    nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
		return -EMSGSIZE;

	if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
		return -EMSGSIZE;

	nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
	if (nla == NULL)
		return -EMSGSIZE;

	memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));

	return 0;
}

static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
			struct sk_buff *skb, struct tcmsg *tm)
{
	struct cls_bpf_prog *prog = fh;
	struct nlattr *nest;
	u32 bpf_flags = 0;
	int ret;

	if (prog == NULL)
		return skb->len;

	tm->tcm_handle = prog->handle;

	cls_bpf_offload_update_stats(tp, prog);

	nest = nla_nest_start(skb, TCA_OPTIONS);
	if (nest == NULL)
		goto nla_put_failure;

	if (prog->res.classid &&
	    nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
		goto nla_put_failure;

	if (cls_bpf_is_ebpf(prog))
		ret = cls_bpf_dump_ebpf_info(prog, skb);
	else
		ret = cls_bpf_dump_bpf_info(prog, skb);
	if (ret)
		goto nla_put_failure;

	if (tcf_exts_dump(skb, &prog->exts) < 0)
		goto nla_put_failure;

	if (prog->exts_integrated)
		bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
	if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
		goto nla_put_failure;
	if (prog->gen_flags &&
	    nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
		goto nla_put_failure;

	nla_nest_end(skb, nest);

	if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
		goto nla_put_failure;

	return skb->len;

nla_put_failure:
	nla_nest_cancel(skb, nest);
	return -1;
}

static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
{
	struct cls_bpf_prog *prog = fh;

	if (prog && prog->res.classid == classid)
		prog->res.class = cl;
}

static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
	struct cls_bpf_head *head = rtnl_dereference(tp->root);
	struct cls_bpf_prog *prog;

	list_for_each_entry(prog, &head->plist, link) {
		if (arg->count < arg->skip)
			goto skip;
		if (arg->fn(tp, prog, arg) < 0) {
			arg->stop = 1;
			break;
		}
skip:
		arg->count++;
	}
}

static int cls_bpf_reoffload(struct tcf_proto *tp, bool add, tc_setup_cb_t *cb,
			     void *cb_priv, struct netlink_ext_ack *extack)
{
	struct cls_bpf_head *head = rtnl_dereference(tp->root);
	struct tcf_block *block = tp->chain->block;
	struct tc_cls_bpf_offload cls_bpf = {};
	struct cls_bpf_prog *prog;
	int err;

	list_for_each_entry(prog, &head->plist, link) {
		if (tc_skip_hw(prog->gen_flags))
			continue;

		tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags,
					   extack);
		cls_bpf.command = TC_CLSBPF_OFFLOAD;
		cls_bpf.exts = &prog->exts;
		cls_bpf.prog = add ? prog->filter : NULL;
		cls_bpf.oldprog = add ? NULL : prog->filter;
		cls_bpf.name = prog->bpf_name;
		cls_bpf.exts_integrated = prog->exts_integrated;

		err = cb(TC_SETUP_CLSBPF, &cls_bpf, cb_priv);
		if (err) {
			if (add && tc_skip_sw(prog->gen_flags))
				return err;
			continue;
		}

		tc_cls_offload_cnt_update(block, &prog->in_hw_count,
					  &prog->gen_flags, add);
	}

	return 0;
}

static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
	.kind		=	"bpf",
	.owner		=	THIS_MODULE,
	.classify	=	cls_bpf_classify,
	.init		=	cls_bpf_init,
	.destroy	=	cls_bpf_destroy,
	.get		=	cls_bpf_get,
	.change		=	cls_bpf_change,
	.delete		=	cls_bpf_delete,
	.walk		=	cls_bpf_walk,
	.reoffload	=	cls_bpf_reoffload,
	.dump		=	cls_bpf_dump,
	.bind_class	=	cls_bpf_bind_class,
};

static int __init cls_bpf_init_mod(void)
{
	return register_tcf_proto_ops(&cls_bpf_ops);
}

static void __exit cls_bpf_exit_mod(void)
{
	unregister_tcf_proto_ops(&cls_bpf_ops);
}

module_init(cls_bpf_init_mod);
module_exit(cls_bpf_exit_mod);