xref: /linux/net/sched/cls_flow.c (revision b85d45947951d23cb22d90caecf4c1eb81342c96)
1 /*
2  * net/sched/cls_flow.c		Generic flow classifier
3  *
4  * Copyright (c) 2007, 2008 Patrick McHardy <kaber@trash.net>
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version 2
9  * of the License, or (at your option) any later version.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/list.h>
15 #include <linux/jhash.h>
16 #include <linux/random.h>
17 #include <linux/pkt_cls.h>
18 #include <linux/skbuff.h>
19 #include <linux/in.h>
20 #include <linux/ip.h>
21 #include <linux/ipv6.h>
22 #include <linux/if_vlan.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 
26 #include <net/pkt_cls.h>
27 #include <net/ip.h>
28 #include <net/route.h>
29 #include <net/flow_dissector.h>
30 
31 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
32 #include <net/netfilter/nf_conntrack.h>
33 #endif
34 
35 struct flow_head {
36 	struct list_head	filters;
37 	struct rcu_head		rcu;
38 };
39 
40 struct flow_filter {
41 	struct list_head	list;
42 	struct tcf_exts		exts;
43 	struct tcf_ematch_tree	ematches;
44 	struct tcf_proto	*tp;
45 	struct timer_list	perturb_timer;
46 	u32			perturb_period;
47 	u32			handle;
48 
49 	u32			nkeys;
50 	u32			keymask;
51 	u32			mode;
52 	u32			mask;
53 	u32			xor;
54 	u32			rshift;
55 	u32			addend;
56 	u32			divisor;
57 	u32			baseclass;
58 	u32			hashrnd;
59 	struct rcu_head		rcu;
60 };
61 
62 static inline u32 addr_fold(void *addr)
63 {
64 	unsigned long a = (unsigned long)addr;
65 
66 	return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0);
67 }
68 
69 static u32 flow_get_src(const struct sk_buff *skb, const struct flow_keys *flow)
70 {
71 	__be32 src = flow_get_u32_src(flow);
72 
73 	if (src)
74 		return ntohl(src);
75 
76 	return addr_fold(skb->sk);
77 }
78 
79 static u32 flow_get_dst(const struct sk_buff *skb, const struct flow_keys *flow)
80 {
81 	__be32 dst = flow_get_u32_dst(flow);
82 
83 	if (dst)
84 		return ntohl(dst);
85 
86 	return addr_fold(skb_dst(skb)) ^ (__force u16) tc_skb_protocol(skb);
87 }
88 
89 static u32 flow_get_proto(const struct sk_buff *skb, const struct flow_keys *flow)
90 {
91 	return flow->basic.ip_proto;
92 }
93 
94 static u32 flow_get_proto_src(const struct sk_buff *skb, const struct flow_keys *flow)
95 {
96 	if (flow->ports.ports)
97 		return ntohs(flow->ports.src);
98 
99 	return addr_fold(skb->sk);
100 }
101 
102 static u32 flow_get_proto_dst(const struct sk_buff *skb, const struct flow_keys *flow)
103 {
104 	if (flow->ports.ports)
105 		return ntohs(flow->ports.dst);
106 
107 	return addr_fold(skb_dst(skb)) ^ (__force u16) tc_skb_protocol(skb);
108 }
109 
110 static u32 flow_get_iif(const struct sk_buff *skb)
111 {
112 	return skb->skb_iif;
113 }
114 
115 static u32 flow_get_priority(const struct sk_buff *skb)
116 {
117 	return skb->priority;
118 }
119 
120 static u32 flow_get_mark(const struct sk_buff *skb)
121 {
122 	return skb->mark;
123 }
124 
125 static u32 flow_get_nfct(const struct sk_buff *skb)
126 {
127 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
128 	return addr_fold(skb->nfct);
129 #else
130 	return 0;
131 #endif
132 }
133 
134 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
135 #define CTTUPLE(skb, member)						\
136 ({									\
137 	enum ip_conntrack_info ctinfo;					\
138 	const struct nf_conn *ct = nf_ct_get(skb, &ctinfo);		\
139 	if (ct == NULL)							\
140 		goto fallback;						\
141 	ct->tuplehash[CTINFO2DIR(ctinfo)].tuple.member;			\
142 })
143 #else
144 #define CTTUPLE(skb, member)						\
145 ({									\
146 	goto fallback;							\
147 	0;								\
148 })
149 #endif
150 
151 static u32 flow_get_nfct_src(const struct sk_buff *skb, const struct flow_keys *flow)
152 {
153 	switch (tc_skb_protocol(skb)) {
154 	case htons(ETH_P_IP):
155 		return ntohl(CTTUPLE(skb, src.u3.ip));
156 	case htons(ETH_P_IPV6):
157 		return ntohl(CTTUPLE(skb, src.u3.ip6[3]));
158 	}
159 fallback:
160 	return flow_get_src(skb, flow);
161 }
162 
163 static u32 flow_get_nfct_dst(const struct sk_buff *skb, const struct flow_keys *flow)
164 {
165 	switch (tc_skb_protocol(skb)) {
166 	case htons(ETH_P_IP):
167 		return ntohl(CTTUPLE(skb, dst.u3.ip));
168 	case htons(ETH_P_IPV6):
169 		return ntohl(CTTUPLE(skb, dst.u3.ip6[3]));
170 	}
171 fallback:
172 	return flow_get_dst(skb, flow);
173 }
174 
175 static u32 flow_get_nfct_proto_src(const struct sk_buff *skb, const struct flow_keys *flow)
176 {
177 	return ntohs(CTTUPLE(skb, src.u.all));
178 fallback:
179 	return flow_get_proto_src(skb, flow);
180 }
181 
182 static u32 flow_get_nfct_proto_dst(const struct sk_buff *skb, const struct flow_keys *flow)
183 {
184 	return ntohs(CTTUPLE(skb, dst.u.all));
185 fallback:
186 	return flow_get_proto_dst(skb, flow);
187 }
188 
189 static u32 flow_get_rtclassid(const struct sk_buff *skb)
190 {
191 #ifdef CONFIG_IP_ROUTE_CLASSID
192 	if (skb_dst(skb))
193 		return skb_dst(skb)->tclassid;
194 #endif
195 	return 0;
196 }
197 
198 static u32 flow_get_skuid(const struct sk_buff *skb)
199 {
200 	if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file) {
201 		kuid_t skuid = skb->sk->sk_socket->file->f_cred->fsuid;
202 		return from_kuid(&init_user_ns, skuid);
203 	}
204 	return 0;
205 }
206 
207 static u32 flow_get_skgid(const struct sk_buff *skb)
208 {
209 	if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file) {
210 		kgid_t skgid = skb->sk->sk_socket->file->f_cred->fsgid;
211 		return from_kgid(&init_user_ns, skgid);
212 	}
213 	return 0;
214 }
215 
216 static u32 flow_get_vlan_tag(const struct sk_buff *skb)
217 {
218 	u16 uninitialized_var(tag);
219 
220 	if (vlan_get_tag(skb, &tag) < 0)
221 		return 0;
222 	return tag & VLAN_VID_MASK;
223 }
224 
225 static u32 flow_get_rxhash(struct sk_buff *skb)
226 {
227 	return skb_get_hash(skb);
228 }
229 
230 static u32 flow_key_get(struct sk_buff *skb, int key, struct flow_keys *flow)
231 {
232 	switch (key) {
233 	case FLOW_KEY_SRC:
234 		return flow_get_src(skb, flow);
235 	case FLOW_KEY_DST:
236 		return flow_get_dst(skb, flow);
237 	case FLOW_KEY_PROTO:
238 		return flow_get_proto(skb, flow);
239 	case FLOW_KEY_PROTO_SRC:
240 		return flow_get_proto_src(skb, flow);
241 	case FLOW_KEY_PROTO_DST:
242 		return flow_get_proto_dst(skb, flow);
243 	case FLOW_KEY_IIF:
244 		return flow_get_iif(skb);
245 	case FLOW_KEY_PRIORITY:
246 		return flow_get_priority(skb);
247 	case FLOW_KEY_MARK:
248 		return flow_get_mark(skb);
249 	case FLOW_KEY_NFCT:
250 		return flow_get_nfct(skb);
251 	case FLOW_KEY_NFCT_SRC:
252 		return flow_get_nfct_src(skb, flow);
253 	case FLOW_KEY_NFCT_DST:
254 		return flow_get_nfct_dst(skb, flow);
255 	case FLOW_KEY_NFCT_PROTO_SRC:
256 		return flow_get_nfct_proto_src(skb, flow);
257 	case FLOW_KEY_NFCT_PROTO_DST:
258 		return flow_get_nfct_proto_dst(skb, flow);
259 	case FLOW_KEY_RTCLASSID:
260 		return flow_get_rtclassid(skb);
261 	case FLOW_KEY_SKUID:
262 		return flow_get_skuid(skb);
263 	case FLOW_KEY_SKGID:
264 		return flow_get_skgid(skb);
265 	case FLOW_KEY_VLAN_TAG:
266 		return flow_get_vlan_tag(skb);
267 	case FLOW_KEY_RXHASH:
268 		return flow_get_rxhash(skb);
269 	default:
270 		WARN_ON(1);
271 		return 0;
272 	}
273 }
274 
275 #define FLOW_KEYS_NEEDED ((1 << FLOW_KEY_SRC) | 		\
276 			  (1 << FLOW_KEY_DST) |			\
277 			  (1 << FLOW_KEY_PROTO) |		\
278 			  (1 << FLOW_KEY_PROTO_SRC) |		\
279 			  (1 << FLOW_KEY_PROTO_DST) | 		\
280 			  (1 << FLOW_KEY_NFCT_SRC) |		\
281 			  (1 << FLOW_KEY_NFCT_DST) |		\
282 			  (1 << FLOW_KEY_NFCT_PROTO_SRC) |	\
283 			  (1 << FLOW_KEY_NFCT_PROTO_DST))
284 
285 static int flow_classify(struct sk_buff *skb, const struct tcf_proto *tp,
286 			 struct tcf_result *res)
287 {
288 	struct flow_head *head = rcu_dereference_bh(tp->root);
289 	struct flow_filter *f;
290 	u32 keymask;
291 	u32 classid;
292 	unsigned int n, key;
293 	int r;
294 
295 	list_for_each_entry_rcu(f, &head->filters, list) {
296 		u32 keys[FLOW_KEY_MAX + 1];
297 		struct flow_keys flow_keys;
298 
299 		if (!tcf_em_tree_match(skb, &f->ematches, NULL))
300 			continue;
301 
302 		keymask = f->keymask;
303 		if (keymask & FLOW_KEYS_NEEDED)
304 			skb_flow_dissect_flow_keys(skb, &flow_keys, 0);
305 
306 		for (n = 0; n < f->nkeys; n++) {
307 			key = ffs(keymask) - 1;
308 			keymask &= ~(1 << key);
309 			keys[n] = flow_key_get(skb, key, &flow_keys);
310 		}
311 
312 		if (f->mode == FLOW_MODE_HASH)
313 			classid = jhash2(keys, f->nkeys, f->hashrnd);
314 		else {
315 			classid = keys[0];
316 			classid = (classid & f->mask) ^ f->xor;
317 			classid = (classid >> f->rshift) + f->addend;
318 		}
319 
320 		if (f->divisor)
321 			classid %= f->divisor;
322 
323 		res->class   = 0;
324 		res->classid = TC_H_MAKE(f->baseclass, f->baseclass + classid);
325 
326 		r = tcf_exts_exec(skb, &f->exts, res);
327 		if (r < 0)
328 			continue;
329 		return r;
330 	}
331 	return -1;
332 }
333 
334 static void flow_perturbation(unsigned long arg)
335 {
336 	struct flow_filter *f = (struct flow_filter *)arg;
337 
338 	get_random_bytes(&f->hashrnd, 4);
339 	if (f->perturb_period)
340 		mod_timer(&f->perturb_timer, jiffies + f->perturb_period);
341 }
342 
343 static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = {
344 	[TCA_FLOW_KEYS]		= { .type = NLA_U32 },
345 	[TCA_FLOW_MODE]		= { .type = NLA_U32 },
346 	[TCA_FLOW_BASECLASS]	= { .type = NLA_U32 },
347 	[TCA_FLOW_RSHIFT]	= { .type = NLA_U32 },
348 	[TCA_FLOW_ADDEND]	= { .type = NLA_U32 },
349 	[TCA_FLOW_MASK]		= { .type = NLA_U32 },
350 	[TCA_FLOW_XOR]		= { .type = NLA_U32 },
351 	[TCA_FLOW_DIVISOR]	= { .type = NLA_U32 },
352 	[TCA_FLOW_ACT]		= { .type = NLA_NESTED },
353 	[TCA_FLOW_POLICE]	= { .type = NLA_NESTED },
354 	[TCA_FLOW_EMATCHES]	= { .type = NLA_NESTED },
355 	[TCA_FLOW_PERTURB]	= { .type = NLA_U32 },
356 };
357 
358 static void flow_destroy_filter(struct rcu_head *head)
359 {
360 	struct flow_filter *f = container_of(head, struct flow_filter, rcu);
361 
362 	del_timer_sync(&f->perturb_timer);
363 	tcf_exts_destroy(&f->exts);
364 	tcf_em_tree_destroy(&f->ematches);
365 	kfree(f);
366 }
367 
368 static int flow_change(struct net *net, struct sk_buff *in_skb,
369 		       struct tcf_proto *tp, unsigned long base,
370 		       u32 handle, struct nlattr **tca,
371 		       unsigned long *arg, bool ovr)
372 {
373 	struct flow_head *head = rtnl_dereference(tp->root);
374 	struct flow_filter *fold, *fnew;
375 	struct nlattr *opt = tca[TCA_OPTIONS];
376 	struct nlattr *tb[TCA_FLOW_MAX + 1];
377 	struct tcf_exts e;
378 	struct tcf_ematch_tree t;
379 	unsigned int nkeys = 0;
380 	unsigned int perturb_period = 0;
381 	u32 baseclass = 0;
382 	u32 keymask = 0;
383 	u32 mode;
384 	int err;
385 
386 	if (opt == NULL)
387 		return -EINVAL;
388 
389 	err = nla_parse_nested(tb, TCA_FLOW_MAX, opt, flow_policy);
390 	if (err < 0)
391 		return err;
392 
393 	if (tb[TCA_FLOW_BASECLASS]) {
394 		baseclass = nla_get_u32(tb[TCA_FLOW_BASECLASS]);
395 		if (TC_H_MIN(baseclass) == 0)
396 			return -EINVAL;
397 	}
398 
399 	if (tb[TCA_FLOW_KEYS]) {
400 		keymask = nla_get_u32(tb[TCA_FLOW_KEYS]);
401 
402 		nkeys = hweight32(keymask);
403 		if (nkeys == 0)
404 			return -EINVAL;
405 
406 		if (fls(keymask) - 1 > FLOW_KEY_MAX)
407 			return -EOPNOTSUPP;
408 
409 		if ((keymask & (FLOW_KEY_SKUID|FLOW_KEY_SKGID)) &&
410 		    sk_user_ns(NETLINK_CB(in_skb).sk) != &init_user_ns)
411 			return -EOPNOTSUPP;
412 	}
413 
414 	tcf_exts_init(&e, TCA_FLOW_ACT, TCA_FLOW_POLICE);
415 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);
416 	if (err < 0)
417 		return err;
418 
419 	err = tcf_em_tree_validate(tp, tb[TCA_FLOW_EMATCHES], &t);
420 	if (err < 0)
421 		goto err1;
422 
423 	err = -ENOBUFS;
424 	fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
425 	if (!fnew)
426 		goto err2;
427 
428 	tcf_exts_init(&fnew->exts, TCA_FLOW_ACT, TCA_FLOW_POLICE);
429 
430 	fold = (struct flow_filter *)*arg;
431 	if (fold) {
432 		err = -EINVAL;
433 		if (fold->handle != handle && handle)
434 			goto err2;
435 
436 		/* Copy fold into fnew */
437 		fnew->tp = fold->tp;
438 		fnew->handle = fold->handle;
439 		fnew->nkeys = fold->nkeys;
440 		fnew->keymask = fold->keymask;
441 		fnew->mode = fold->mode;
442 		fnew->mask = fold->mask;
443 		fnew->xor = fold->xor;
444 		fnew->rshift = fold->rshift;
445 		fnew->addend = fold->addend;
446 		fnew->divisor = fold->divisor;
447 		fnew->baseclass = fold->baseclass;
448 		fnew->hashrnd = fold->hashrnd;
449 
450 		mode = fold->mode;
451 		if (tb[TCA_FLOW_MODE])
452 			mode = nla_get_u32(tb[TCA_FLOW_MODE]);
453 		if (mode != FLOW_MODE_HASH && nkeys > 1)
454 			goto err2;
455 
456 		if (mode == FLOW_MODE_HASH)
457 			perturb_period = fold->perturb_period;
458 		if (tb[TCA_FLOW_PERTURB]) {
459 			if (mode != FLOW_MODE_HASH)
460 				goto err2;
461 			perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
462 		}
463 	} else {
464 		err = -EINVAL;
465 		if (!handle)
466 			goto err2;
467 		if (!tb[TCA_FLOW_KEYS])
468 			goto err2;
469 
470 		mode = FLOW_MODE_MAP;
471 		if (tb[TCA_FLOW_MODE])
472 			mode = nla_get_u32(tb[TCA_FLOW_MODE]);
473 		if (mode != FLOW_MODE_HASH && nkeys > 1)
474 			goto err2;
475 
476 		if (tb[TCA_FLOW_PERTURB]) {
477 			if (mode != FLOW_MODE_HASH)
478 				goto err2;
479 			perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
480 		}
481 
482 		if (TC_H_MAJ(baseclass) == 0)
483 			baseclass = TC_H_MAKE(tp->q->handle, baseclass);
484 		if (TC_H_MIN(baseclass) == 0)
485 			baseclass = TC_H_MAKE(baseclass, 1);
486 
487 		fnew->handle = handle;
488 		fnew->mask  = ~0U;
489 		fnew->tp = tp;
490 		get_random_bytes(&fnew->hashrnd, 4);
491 	}
492 
493 	fnew->perturb_timer.function = flow_perturbation;
494 	fnew->perturb_timer.data = (unsigned long)fnew;
495 	init_timer_deferrable(&fnew->perturb_timer);
496 
497 	tcf_exts_change(tp, &fnew->exts, &e);
498 	tcf_em_tree_change(tp, &fnew->ematches, &t);
499 
500 	netif_keep_dst(qdisc_dev(tp->q));
501 
502 	if (tb[TCA_FLOW_KEYS]) {
503 		fnew->keymask = keymask;
504 		fnew->nkeys   = nkeys;
505 	}
506 
507 	fnew->mode = mode;
508 
509 	if (tb[TCA_FLOW_MASK])
510 		fnew->mask = nla_get_u32(tb[TCA_FLOW_MASK]);
511 	if (tb[TCA_FLOW_XOR])
512 		fnew->xor = nla_get_u32(tb[TCA_FLOW_XOR]);
513 	if (tb[TCA_FLOW_RSHIFT])
514 		fnew->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]);
515 	if (tb[TCA_FLOW_ADDEND])
516 		fnew->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]);
517 
518 	if (tb[TCA_FLOW_DIVISOR])
519 		fnew->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]);
520 	if (baseclass)
521 		fnew->baseclass = baseclass;
522 
523 	fnew->perturb_period = perturb_period;
524 	if (perturb_period)
525 		mod_timer(&fnew->perturb_timer, jiffies + perturb_period);
526 
527 	if (*arg == 0)
528 		list_add_tail_rcu(&fnew->list, &head->filters);
529 	else
530 		list_replace_rcu(&fold->list, &fnew->list);
531 
532 	*arg = (unsigned long)fnew;
533 
534 	if (fold)
535 		call_rcu(&fold->rcu, flow_destroy_filter);
536 	return 0;
537 
538 err2:
539 	tcf_em_tree_destroy(&t);
540 	kfree(fnew);
541 err1:
542 	tcf_exts_destroy(&e);
543 	return err;
544 }
545 
546 static int flow_delete(struct tcf_proto *tp, unsigned long arg)
547 {
548 	struct flow_filter *f = (struct flow_filter *)arg;
549 
550 	list_del_rcu(&f->list);
551 	call_rcu(&f->rcu, flow_destroy_filter);
552 	return 0;
553 }
554 
555 static int flow_init(struct tcf_proto *tp)
556 {
557 	struct flow_head *head;
558 
559 	head = kzalloc(sizeof(*head), GFP_KERNEL);
560 	if (head == NULL)
561 		return -ENOBUFS;
562 	INIT_LIST_HEAD(&head->filters);
563 	rcu_assign_pointer(tp->root, head);
564 	return 0;
565 }
566 
567 static bool flow_destroy(struct tcf_proto *tp, bool force)
568 {
569 	struct flow_head *head = rtnl_dereference(tp->root);
570 	struct flow_filter *f, *next;
571 
572 	if (!force && !list_empty(&head->filters))
573 		return false;
574 
575 	list_for_each_entry_safe(f, next, &head->filters, list) {
576 		list_del_rcu(&f->list);
577 		call_rcu(&f->rcu, flow_destroy_filter);
578 	}
579 	RCU_INIT_POINTER(tp->root, NULL);
580 	kfree_rcu(head, rcu);
581 	return true;
582 }
583 
584 static unsigned long flow_get(struct tcf_proto *tp, u32 handle)
585 {
586 	struct flow_head *head = rtnl_dereference(tp->root);
587 	struct flow_filter *f;
588 
589 	list_for_each_entry(f, &head->filters, list)
590 		if (f->handle == handle)
591 			return (unsigned long)f;
592 	return 0;
593 }
594 
595 static int flow_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
596 		     struct sk_buff *skb, struct tcmsg *t)
597 {
598 	struct flow_filter *f = (struct flow_filter *)fh;
599 	struct nlattr *nest;
600 
601 	if (f == NULL)
602 		return skb->len;
603 
604 	t->tcm_handle = f->handle;
605 
606 	nest = nla_nest_start(skb, TCA_OPTIONS);
607 	if (nest == NULL)
608 		goto nla_put_failure;
609 
610 	if (nla_put_u32(skb, TCA_FLOW_KEYS, f->keymask) ||
611 	    nla_put_u32(skb, TCA_FLOW_MODE, f->mode))
612 		goto nla_put_failure;
613 
614 	if (f->mask != ~0 || f->xor != 0) {
615 		if (nla_put_u32(skb, TCA_FLOW_MASK, f->mask) ||
616 		    nla_put_u32(skb, TCA_FLOW_XOR, f->xor))
617 			goto nla_put_failure;
618 	}
619 	if (f->rshift &&
620 	    nla_put_u32(skb, TCA_FLOW_RSHIFT, f->rshift))
621 		goto nla_put_failure;
622 	if (f->addend &&
623 	    nla_put_u32(skb, TCA_FLOW_ADDEND, f->addend))
624 		goto nla_put_failure;
625 
626 	if (f->divisor &&
627 	    nla_put_u32(skb, TCA_FLOW_DIVISOR, f->divisor))
628 		goto nla_put_failure;
629 	if (f->baseclass &&
630 	    nla_put_u32(skb, TCA_FLOW_BASECLASS, f->baseclass))
631 		goto nla_put_failure;
632 
633 	if (f->perturb_period &&
634 	    nla_put_u32(skb, TCA_FLOW_PERTURB, f->perturb_period / HZ))
635 		goto nla_put_failure;
636 
637 	if (tcf_exts_dump(skb, &f->exts) < 0)
638 		goto nla_put_failure;
639 #ifdef CONFIG_NET_EMATCH
640 	if (f->ematches.hdr.nmatches &&
641 	    tcf_em_tree_dump(skb, &f->ematches, TCA_FLOW_EMATCHES) < 0)
642 		goto nla_put_failure;
643 #endif
644 	nla_nest_end(skb, nest);
645 
646 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
647 		goto nla_put_failure;
648 
649 	return skb->len;
650 
651 nla_put_failure:
652 	nla_nest_cancel(skb, nest);
653 	return -1;
654 }
655 
656 static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg)
657 {
658 	struct flow_head *head = rtnl_dereference(tp->root);
659 	struct flow_filter *f;
660 
661 	list_for_each_entry(f, &head->filters, list) {
662 		if (arg->count < arg->skip)
663 			goto skip;
664 		if (arg->fn(tp, (unsigned long)f, arg) < 0) {
665 			arg->stop = 1;
666 			break;
667 		}
668 skip:
669 		arg->count++;
670 	}
671 }
672 
673 static struct tcf_proto_ops cls_flow_ops __read_mostly = {
674 	.kind		= "flow",
675 	.classify	= flow_classify,
676 	.init		= flow_init,
677 	.destroy	= flow_destroy,
678 	.change		= flow_change,
679 	.delete		= flow_delete,
680 	.get		= flow_get,
681 	.dump		= flow_dump,
682 	.walk		= flow_walk,
683 	.owner		= THIS_MODULE,
684 };
685 
686 static int __init cls_flow_init(void)
687 {
688 	return register_tcf_proto_ops(&cls_flow_ops);
689 }
690 
691 static void __exit cls_flow_exit(void)
692 {
693 	unregister_tcf_proto_ops(&cls_flow_ops);
694 }
695 
696 module_init(cls_flow_init);
697 module_exit(cls_flow_exit);
698 
699 MODULE_LICENSE("GPL");
700 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
701 MODULE_DESCRIPTION("TC flow classifier");
702