xref: /openbmc/linux/net/sched/cls_bpf.c (revision 9be08a27)
1 /*
2  * Berkeley Packet Filter based traffic classifier
3  *
4  * Might be used to classify traffic through flexible, user-defined and
5  * possibly JIT-ed BPF filters for traffic control as an alternative to
6  * ematches.
7  *
8  * (C) 2013 Daniel Borkmann <dborkman@redhat.com>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13  */
14 
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/skbuff.h>
18 #include <linux/filter.h>
19 #include <linux/bpf.h>
20 #include <linux/idr.h>
21 
22 #include <net/rtnetlink.h>
23 #include <net/pkt_cls.h>
24 #include <net/sock.h>
25 
26 MODULE_LICENSE("GPL");
27 MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
28 MODULE_DESCRIPTION("TC BPF based classifier");
29 
30 #define CLS_BPF_NAME_LEN	256
31 #define CLS_BPF_SUPPORTED_GEN_FLAGS		\
32 	(TCA_CLS_FLAGS_SKIP_HW | TCA_CLS_FLAGS_SKIP_SW)
33 
34 struct cls_bpf_head {
35 	struct list_head plist;
36 	struct idr handle_idr;
37 	struct rcu_head rcu;
38 };
39 
40 struct cls_bpf_prog {
41 	struct bpf_prog *filter;
42 	struct list_head link;
43 	struct tcf_result res;
44 	bool exts_integrated;
45 	u32 gen_flags;
46 	unsigned int in_hw_count;
47 	struct tcf_exts exts;
48 	u32 handle;
49 	u16 bpf_num_ops;
50 	struct sock_filter *bpf_ops;
51 	const char *bpf_name;
52 	struct tcf_proto *tp;
53 	struct rcu_work rwork;
54 };
55 
56 static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
57 	[TCA_BPF_CLASSID]	= { .type = NLA_U32 },
58 	[TCA_BPF_FLAGS]		= { .type = NLA_U32 },
59 	[TCA_BPF_FLAGS_GEN]	= { .type = NLA_U32 },
60 	[TCA_BPF_FD]		= { .type = NLA_U32 },
61 	[TCA_BPF_NAME]		= { .type = NLA_NUL_STRING,
62 				    .len = CLS_BPF_NAME_LEN },
63 	[TCA_BPF_OPS_LEN]	= { .type = NLA_U16 },
64 	[TCA_BPF_OPS]		= { .type = NLA_BINARY,
65 				    .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
66 };
67 
68 static int cls_bpf_exec_opcode(int code)
69 {
70 	switch (code) {
71 	case TC_ACT_OK:
72 	case TC_ACT_SHOT:
73 	case TC_ACT_STOLEN:
74 	case TC_ACT_TRAP:
75 	case TC_ACT_REDIRECT:
76 	case TC_ACT_UNSPEC:
77 		return code;
78 	default:
79 		return TC_ACT_UNSPEC;
80 	}
81 }
82 
83 static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
84 			    struct tcf_result *res)
85 {
86 	struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
87 	bool at_ingress = skb_at_tc_ingress(skb);
88 	struct cls_bpf_prog *prog;
89 	int ret = -1;
90 
91 	/* Needed here for accessing maps. */
92 	rcu_read_lock();
93 	list_for_each_entry_rcu(prog, &head->plist, link) {
94 		int filter_res;
95 
96 		qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
97 
98 		if (tc_skip_sw(prog->gen_flags)) {
99 			filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0;
100 		} else if (at_ingress) {
101 			/* It is safe to push/pull even if skb_shared() */
102 			__skb_push(skb, skb->mac_len);
103 			bpf_compute_data_pointers(skb);
104 			filter_res = BPF_PROG_RUN(prog->filter, skb);
105 			__skb_pull(skb, skb->mac_len);
106 		} else {
107 			bpf_compute_data_pointers(skb);
108 			filter_res = BPF_PROG_RUN(prog->filter, skb);
109 		}
110 
111 		if (prog->exts_integrated) {
112 			res->class   = 0;
113 			res->classid = TC_H_MAJ(prog->res.classid) |
114 				       qdisc_skb_cb(skb)->tc_classid;
115 
116 			ret = cls_bpf_exec_opcode(filter_res);
117 			if (ret == TC_ACT_UNSPEC)
118 				continue;
119 			break;
120 		}
121 
122 		if (filter_res == 0)
123 			continue;
124 		if (filter_res != -1) {
125 			res->class   = 0;
126 			res->classid = filter_res;
127 		} else {
128 			*res = prog->res;
129 		}
130 
131 		ret = tcf_exts_exec(skb, &prog->exts, res);
132 		if (ret < 0)
133 			continue;
134 
135 		break;
136 	}
137 	rcu_read_unlock();
138 
139 	return ret;
140 }
141 
142 static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
143 {
144 	return !prog->bpf_ops;
145 }
146 
147 static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
148 			       struct cls_bpf_prog *oldprog,
149 			       struct netlink_ext_ack *extack)
150 {
151 	struct tcf_block *block = tp->chain->block;
152 	struct tc_cls_bpf_offload cls_bpf = {};
153 	struct cls_bpf_prog *obj;
154 	bool skip_sw;
155 	int err;
156 
157 	skip_sw = prog && tc_skip_sw(prog->gen_flags);
158 	obj = prog ?: oldprog;
159 
160 	tc_cls_common_offload_init(&cls_bpf.common, tp, obj->gen_flags,
161 				   extack);
162 	cls_bpf.command = TC_CLSBPF_OFFLOAD;
163 	cls_bpf.exts = &obj->exts;
164 	cls_bpf.prog = prog ? prog->filter : NULL;
165 	cls_bpf.oldprog = oldprog ? oldprog->filter : NULL;
166 	cls_bpf.name = obj->bpf_name;
167 	cls_bpf.exts_integrated = obj->exts_integrated;
168 
169 	if (oldprog)
170 		tcf_block_offload_dec(block, &oldprog->gen_flags);
171 
172 	err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, skip_sw);
173 	if (prog) {
174 		if (err < 0) {
175 			cls_bpf_offload_cmd(tp, oldprog, prog, extack);
176 			return err;
177 		} else if (err > 0) {
178 			prog->in_hw_count = err;
179 			tcf_block_offload_inc(block, &prog->gen_flags);
180 		}
181 	}
182 
183 	if (prog && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
184 		return -EINVAL;
185 
186 	return 0;
187 }
188 
189 static u32 cls_bpf_flags(u32 flags)
190 {
191 	return flags & CLS_BPF_SUPPORTED_GEN_FLAGS;
192 }
193 
194 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
195 			   struct cls_bpf_prog *oldprog,
196 			   struct netlink_ext_ack *extack)
197 {
198 	if (prog && oldprog &&
199 	    cls_bpf_flags(prog->gen_flags) !=
200 	    cls_bpf_flags(oldprog->gen_flags))
201 		return -EINVAL;
202 
203 	if (prog && tc_skip_hw(prog->gen_flags))
204 		prog = NULL;
205 	if (oldprog && tc_skip_hw(oldprog->gen_flags))
206 		oldprog = NULL;
207 	if (!prog && !oldprog)
208 		return 0;
209 
210 	return cls_bpf_offload_cmd(tp, prog, oldprog, extack);
211 }
212 
213 static void cls_bpf_stop_offload(struct tcf_proto *tp,
214 				 struct cls_bpf_prog *prog,
215 				 struct netlink_ext_ack *extack)
216 {
217 	int err;
218 
219 	err = cls_bpf_offload_cmd(tp, NULL, prog, extack);
220 	if (err)
221 		pr_err("Stopping hardware offload failed: %d\n", err);
222 }
223 
224 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
225 					 struct cls_bpf_prog *prog)
226 {
227 	struct tcf_block *block = tp->chain->block;
228 	struct tc_cls_bpf_offload cls_bpf = {};
229 
230 	tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags, NULL);
231 	cls_bpf.command = TC_CLSBPF_STATS;
232 	cls_bpf.exts = &prog->exts;
233 	cls_bpf.prog = prog->filter;
234 	cls_bpf.name = prog->bpf_name;
235 	cls_bpf.exts_integrated = prog->exts_integrated;
236 
237 	tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, false);
238 }
239 
240 static int cls_bpf_init(struct tcf_proto *tp)
241 {
242 	struct cls_bpf_head *head;
243 
244 	head = kzalloc(sizeof(*head), GFP_KERNEL);
245 	if (head == NULL)
246 		return -ENOBUFS;
247 
248 	INIT_LIST_HEAD_RCU(&head->plist);
249 	idr_init(&head->handle_idr);
250 	rcu_assign_pointer(tp->root, head);
251 
252 	return 0;
253 }
254 
255 static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
256 {
257 	if (cls_bpf_is_ebpf(prog))
258 		bpf_prog_put(prog->filter);
259 	else
260 		bpf_prog_destroy(prog->filter);
261 
262 	kfree(prog->bpf_name);
263 	kfree(prog->bpf_ops);
264 }
265 
266 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
267 {
268 	tcf_exts_destroy(&prog->exts);
269 	tcf_exts_put_net(&prog->exts);
270 
271 	cls_bpf_free_parms(prog);
272 	kfree(prog);
273 }
274 
275 static void cls_bpf_delete_prog_work(struct work_struct *work)
276 {
277 	struct cls_bpf_prog *prog = container_of(to_rcu_work(work),
278 						 struct cls_bpf_prog,
279 						 rwork);
280 	rtnl_lock();
281 	__cls_bpf_delete_prog(prog);
282 	rtnl_unlock();
283 }
284 
285 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
286 			     struct netlink_ext_ack *extack)
287 {
288 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
289 
290 	idr_remove(&head->handle_idr, prog->handle);
291 	cls_bpf_stop_offload(tp, prog, extack);
292 	list_del_rcu(&prog->link);
293 	tcf_unbind_filter(tp, &prog->res);
294 	if (tcf_exts_get_net(&prog->exts))
295 		tcf_queue_work(&prog->rwork, cls_bpf_delete_prog_work);
296 	else
297 		__cls_bpf_delete_prog(prog);
298 }
299 
300 static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last,
301 			  struct netlink_ext_ack *extack)
302 {
303 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
304 
305 	__cls_bpf_delete(tp, arg, extack);
306 	*last = list_empty(&head->plist);
307 	return 0;
308 }
309 
310 static void cls_bpf_destroy(struct tcf_proto *tp,
311 			    struct netlink_ext_ack *extack)
312 {
313 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
314 	struct cls_bpf_prog *prog, *tmp;
315 
316 	list_for_each_entry_safe(prog, tmp, &head->plist, link)
317 		__cls_bpf_delete(tp, prog, extack);
318 
319 	idr_destroy(&head->handle_idr);
320 	kfree_rcu(head, rcu);
321 }
322 
323 static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
324 {
325 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
326 	struct cls_bpf_prog *prog;
327 
328 	list_for_each_entry(prog, &head->plist, link) {
329 		if (prog->handle == handle)
330 			return prog;
331 	}
332 
333 	return NULL;
334 }
335 
336 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
337 {
338 	struct sock_filter *bpf_ops;
339 	struct sock_fprog_kern fprog_tmp;
340 	struct bpf_prog *fp;
341 	u16 bpf_size, bpf_num_ops;
342 	int ret;
343 
344 	bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
345 	if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
346 		return -EINVAL;
347 
348 	bpf_size = bpf_num_ops * sizeof(*bpf_ops);
349 	if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
350 		return -EINVAL;
351 
352 	bpf_ops = kmemdup(nla_data(tb[TCA_BPF_OPS]), bpf_size, GFP_KERNEL);
353 	if (bpf_ops == NULL)
354 		return -ENOMEM;
355 
356 	fprog_tmp.len = bpf_num_ops;
357 	fprog_tmp.filter = bpf_ops;
358 
359 	ret = bpf_prog_create(&fp, &fprog_tmp);
360 	if (ret < 0) {
361 		kfree(bpf_ops);
362 		return ret;
363 	}
364 
365 	prog->bpf_ops = bpf_ops;
366 	prog->bpf_num_ops = bpf_num_ops;
367 	prog->bpf_name = NULL;
368 	prog->filter = fp;
369 
370 	return 0;
371 }
372 
373 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
374 				 u32 gen_flags, const struct tcf_proto *tp)
375 {
376 	struct bpf_prog *fp;
377 	char *name = NULL;
378 	bool skip_sw;
379 	u32 bpf_fd;
380 
381 	bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
382 	skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW;
383 
384 	fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw);
385 	if (IS_ERR(fp))
386 		return PTR_ERR(fp);
387 
388 	if (tb[TCA_BPF_NAME]) {
389 		name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
390 		if (!name) {
391 			bpf_prog_put(fp);
392 			return -ENOMEM;
393 		}
394 	}
395 
396 	prog->bpf_ops = NULL;
397 	prog->bpf_name = name;
398 	prog->filter = fp;
399 
400 	if (fp->dst_needed)
401 		tcf_block_netif_keep_dst(tp->chain->block);
402 
403 	return 0;
404 }
405 
406 static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
407 			     struct cls_bpf_prog *prog, unsigned long base,
408 			     struct nlattr **tb, struct nlattr *est, bool ovr,
409 			     struct netlink_ext_ack *extack)
410 {
411 	bool is_bpf, is_ebpf, have_exts = false;
412 	u32 gen_flags = 0;
413 	int ret;
414 
415 	is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
416 	is_ebpf = tb[TCA_BPF_FD];
417 	if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
418 		return -EINVAL;
419 
420 	ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr, extack);
421 	if (ret < 0)
422 		return ret;
423 
424 	if (tb[TCA_BPF_FLAGS]) {
425 		u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
426 
427 		if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
428 			return -EINVAL;
429 
430 		have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
431 	}
432 	if (tb[TCA_BPF_FLAGS_GEN]) {
433 		gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
434 		if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
435 		    !tc_flags_valid(gen_flags))
436 			return -EINVAL;
437 	}
438 
439 	prog->exts_integrated = have_exts;
440 	prog->gen_flags = gen_flags;
441 
442 	ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
443 		       cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
444 	if (ret < 0)
445 		return ret;
446 
447 	if (tb[TCA_BPF_CLASSID]) {
448 		prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
449 		tcf_bind_filter(tp, &prog->res, base);
450 	}
451 
452 	return 0;
453 }
454 
455 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
456 			  struct tcf_proto *tp, unsigned long base,
457 			  u32 handle, struct nlattr **tca,
458 			  void **arg, bool ovr, struct netlink_ext_ack *extack)
459 {
460 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
461 	struct cls_bpf_prog *oldprog = *arg;
462 	struct nlattr *tb[TCA_BPF_MAX + 1];
463 	struct cls_bpf_prog *prog;
464 	int ret;
465 
466 	if (tca[TCA_OPTIONS] == NULL)
467 		return -EINVAL;
468 
469 	ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
470 			       NULL);
471 	if (ret < 0)
472 		return ret;
473 
474 	prog = kzalloc(sizeof(*prog), GFP_KERNEL);
475 	if (!prog)
476 		return -ENOBUFS;
477 
478 	ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
479 	if (ret < 0)
480 		goto errout;
481 
482 	if (oldprog) {
483 		if (handle && oldprog->handle != handle) {
484 			ret = -EINVAL;
485 			goto errout;
486 		}
487 	}
488 
489 	if (handle == 0) {
490 		handle = 1;
491 		ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
492 				    INT_MAX, GFP_KERNEL);
493 	} else if (!oldprog) {
494 		ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
495 				    handle, GFP_KERNEL);
496 	}
497 
498 	if (ret)
499 		goto errout;
500 	prog->handle = handle;
501 
502 	ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr,
503 				extack);
504 	if (ret < 0)
505 		goto errout_idr;
506 
507 	ret = cls_bpf_offload(tp, prog, oldprog, extack);
508 	if (ret)
509 		goto errout_parms;
510 
511 	if (!tc_in_hw(prog->gen_flags))
512 		prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
513 
514 	if (oldprog) {
515 		idr_replace(&head->handle_idr, prog, handle);
516 		list_replace_rcu(&oldprog->link, &prog->link);
517 		tcf_unbind_filter(tp, &oldprog->res);
518 		tcf_exts_get_net(&oldprog->exts);
519 		tcf_queue_work(&oldprog->rwork, cls_bpf_delete_prog_work);
520 	} else {
521 		list_add_rcu(&prog->link, &head->plist);
522 	}
523 
524 	*arg = prog;
525 	return 0;
526 
527 errout_parms:
528 	cls_bpf_free_parms(prog);
529 errout_idr:
530 	if (!oldprog)
531 		idr_remove(&head->handle_idr, prog->handle);
532 errout:
533 	tcf_exts_destroy(&prog->exts);
534 	kfree(prog);
535 	return ret;
536 }
537 
538 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
539 				 struct sk_buff *skb)
540 {
541 	struct nlattr *nla;
542 
543 	if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
544 		return -EMSGSIZE;
545 
546 	nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
547 			  sizeof(struct sock_filter));
548 	if (nla == NULL)
549 		return -EMSGSIZE;
550 
551 	memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
552 
553 	return 0;
554 }
555 
556 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
557 				  struct sk_buff *skb)
558 {
559 	struct nlattr *nla;
560 
561 	if (prog->bpf_name &&
562 	    nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
563 		return -EMSGSIZE;
564 
565 	if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
566 		return -EMSGSIZE;
567 
568 	nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
569 	if (nla == NULL)
570 		return -EMSGSIZE;
571 
572 	memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
573 
574 	return 0;
575 }
576 
577 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
578 			struct sk_buff *skb, struct tcmsg *tm)
579 {
580 	struct cls_bpf_prog *prog = fh;
581 	struct nlattr *nest;
582 	u32 bpf_flags = 0;
583 	int ret;
584 
585 	if (prog == NULL)
586 		return skb->len;
587 
588 	tm->tcm_handle = prog->handle;
589 
590 	cls_bpf_offload_update_stats(tp, prog);
591 
592 	nest = nla_nest_start(skb, TCA_OPTIONS);
593 	if (nest == NULL)
594 		goto nla_put_failure;
595 
596 	if (prog->res.classid &&
597 	    nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
598 		goto nla_put_failure;
599 
600 	if (cls_bpf_is_ebpf(prog))
601 		ret = cls_bpf_dump_ebpf_info(prog, skb);
602 	else
603 		ret = cls_bpf_dump_bpf_info(prog, skb);
604 	if (ret)
605 		goto nla_put_failure;
606 
607 	if (tcf_exts_dump(skb, &prog->exts) < 0)
608 		goto nla_put_failure;
609 
610 	if (prog->exts_integrated)
611 		bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
612 	if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
613 		goto nla_put_failure;
614 	if (prog->gen_flags &&
615 	    nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
616 		goto nla_put_failure;
617 
618 	nla_nest_end(skb, nest);
619 
620 	if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
621 		goto nla_put_failure;
622 
623 	return skb->len;
624 
625 nla_put_failure:
626 	nla_nest_cancel(skb, nest);
627 	return -1;
628 }
629 
630 static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
631 {
632 	struct cls_bpf_prog *prog = fh;
633 
634 	if (prog && prog->res.classid == classid)
635 		prog->res.class = cl;
636 }
637 
638 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
639 {
640 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
641 	struct cls_bpf_prog *prog;
642 
643 	list_for_each_entry(prog, &head->plist, link) {
644 		if (arg->count < arg->skip)
645 			goto skip;
646 		if (arg->fn(tp, prog, arg) < 0) {
647 			arg->stop = 1;
648 			break;
649 		}
650 skip:
651 		arg->count++;
652 	}
653 }
654 
655 static int cls_bpf_reoffload(struct tcf_proto *tp, bool add, tc_setup_cb_t *cb,
656 			     void *cb_priv, struct netlink_ext_ack *extack)
657 {
658 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
659 	struct tcf_block *block = tp->chain->block;
660 	struct tc_cls_bpf_offload cls_bpf = {};
661 	struct cls_bpf_prog *prog;
662 	int err;
663 
664 	list_for_each_entry(prog, &head->plist, link) {
665 		if (tc_skip_hw(prog->gen_flags))
666 			continue;
667 
668 		tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags,
669 					   extack);
670 		cls_bpf.command = TC_CLSBPF_OFFLOAD;
671 		cls_bpf.exts = &prog->exts;
672 		cls_bpf.prog = add ? prog->filter : NULL;
673 		cls_bpf.oldprog = add ? NULL : prog->filter;
674 		cls_bpf.name = prog->bpf_name;
675 		cls_bpf.exts_integrated = prog->exts_integrated;
676 
677 		err = cb(TC_SETUP_CLSBPF, &cls_bpf, cb_priv);
678 		if (err) {
679 			if (add && tc_skip_sw(prog->gen_flags))
680 				return err;
681 			continue;
682 		}
683 
684 		tc_cls_offload_cnt_update(block, &prog->in_hw_count,
685 					  &prog->gen_flags, add);
686 	}
687 
688 	return 0;
689 }
690 
691 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
692 	.kind		=	"bpf",
693 	.owner		=	THIS_MODULE,
694 	.classify	=	cls_bpf_classify,
695 	.init		=	cls_bpf_init,
696 	.destroy	=	cls_bpf_destroy,
697 	.get		=	cls_bpf_get,
698 	.change		=	cls_bpf_change,
699 	.delete		=	cls_bpf_delete,
700 	.walk		=	cls_bpf_walk,
701 	.reoffload	=	cls_bpf_reoffload,
702 	.dump		=	cls_bpf_dump,
703 	.bind_class	=	cls_bpf_bind_class,
704 };
705 
706 static int __init cls_bpf_init_mod(void)
707 {
708 	return register_tcf_proto_ops(&cls_bpf_ops);
709 }
710 
711 static void __exit cls_bpf_exit_mod(void)
712 {
713 	unregister_tcf_proto_ops(&cls_bpf_ops);
714 }
715 
716 module_init(cls_bpf_init_mod);
717 module_exit(cls_bpf_exit_mod);
718