xref: /openbmc/linux/net/sched/cls_flow.c (revision 6a108a14)
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 
25 #include <net/pkt_cls.h>
26 #include <net/ip.h>
27 #include <net/route.h>
28 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
29 #include <net/netfilter/nf_conntrack.h>
30 #endif
31 
32 struct flow_head {
33 	struct list_head	filters;
34 };
35 
36 struct flow_filter {
37 	struct list_head	list;
38 	struct tcf_exts		exts;
39 	struct tcf_ematch_tree	ematches;
40 	struct timer_list	perturb_timer;
41 	u32			perturb_period;
42 	u32			handle;
43 
44 	u32			nkeys;
45 	u32			keymask;
46 	u32			mode;
47 	u32			mask;
48 	u32			xor;
49 	u32			rshift;
50 	u32			addend;
51 	u32			divisor;
52 	u32			baseclass;
53 	u32			hashrnd;
54 };
55 
56 static const struct tcf_ext_map flow_ext_map = {
57 	.action	= TCA_FLOW_ACT,
58 	.police	= TCA_FLOW_POLICE,
59 };
60 
61 static inline u32 addr_fold(void *addr)
62 {
63 	unsigned long a = (unsigned long)addr;
64 
65 	return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0);
66 }
67 
68 static u32 flow_get_src(struct sk_buff *skb)
69 {
70 	switch (skb->protocol) {
71 	case htons(ETH_P_IP):
72 		if (pskb_network_may_pull(skb, sizeof(struct iphdr)))
73 			return ntohl(ip_hdr(skb)->saddr);
74 		break;
75 	case htons(ETH_P_IPV6):
76 		if (pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
77 			return ntohl(ipv6_hdr(skb)->saddr.s6_addr32[3]);
78 		break;
79 	}
80 
81 	return addr_fold(skb->sk);
82 }
83 
84 static u32 flow_get_dst(struct sk_buff *skb)
85 {
86 	switch (skb->protocol) {
87 	case htons(ETH_P_IP):
88 		if (pskb_network_may_pull(skb, sizeof(struct iphdr)))
89 			return ntohl(ip_hdr(skb)->daddr);
90 		break;
91 	case htons(ETH_P_IPV6):
92 		if (pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
93 			return ntohl(ipv6_hdr(skb)->daddr.s6_addr32[3]);
94 		break;
95 	}
96 
97 	return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol;
98 }
99 
100 static u32 flow_get_proto(struct sk_buff *skb)
101 {
102 	switch (skb->protocol) {
103 	case htons(ETH_P_IP):
104 		return pskb_network_may_pull(skb, sizeof(struct iphdr)) ?
105 		       ip_hdr(skb)->protocol : 0;
106 	case htons(ETH_P_IPV6):
107 		return pskb_network_may_pull(skb, sizeof(struct ipv6hdr)) ?
108 		       ipv6_hdr(skb)->nexthdr : 0;
109 	default:
110 		return 0;
111 	}
112 }
113 
114 static u32 flow_get_proto_src(struct sk_buff *skb)
115 {
116 	switch (skb->protocol) {
117 	case htons(ETH_P_IP): {
118 		struct iphdr *iph;
119 		int poff;
120 
121 		if (!pskb_network_may_pull(skb, sizeof(*iph)))
122 			break;
123 		iph = ip_hdr(skb);
124 		if (iph->frag_off & htons(IP_MF|IP_OFFSET))
125 			break;
126 		poff = proto_ports_offset(iph->protocol);
127 		if (poff >= 0 &&
128 		    pskb_network_may_pull(skb, iph->ihl * 4 + 2 + poff)) {
129 			iph = ip_hdr(skb);
130 			return ntohs(*(__be16 *)((void *)iph + iph->ihl * 4 +
131 						 poff));
132 		}
133 		break;
134 	}
135 	case htons(ETH_P_IPV6): {
136 		struct ipv6hdr *iph;
137 		int poff;
138 
139 		if (!pskb_network_may_pull(skb, sizeof(*iph)))
140 			break;
141 		iph = ipv6_hdr(skb);
142 		poff = proto_ports_offset(iph->nexthdr);
143 		if (poff >= 0 &&
144 		    pskb_network_may_pull(skb, sizeof(*iph) + poff + 2)) {
145 			iph = ipv6_hdr(skb);
146 			return ntohs(*(__be16 *)((void *)iph + sizeof(*iph) +
147 						 poff));
148 		}
149 		break;
150 	}
151 	}
152 
153 	return addr_fold(skb->sk);
154 }
155 
156 static u32 flow_get_proto_dst(struct sk_buff *skb)
157 {
158 	switch (skb->protocol) {
159 	case htons(ETH_P_IP): {
160 		struct iphdr *iph;
161 		int poff;
162 
163 		if (!pskb_network_may_pull(skb, sizeof(*iph)))
164 			break;
165 		iph = ip_hdr(skb);
166 		if (iph->frag_off & htons(IP_MF|IP_OFFSET))
167 			break;
168 		poff = proto_ports_offset(iph->protocol);
169 		if (poff >= 0 &&
170 		    pskb_network_may_pull(skb, iph->ihl * 4 + 4 + poff)) {
171 			iph = ip_hdr(skb);
172 			return ntohs(*(__be16 *)((void *)iph + iph->ihl * 4 +
173 						 2 + poff));
174 		}
175 		break;
176 	}
177 	case htons(ETH_P_IPV6): {
178 		struct ipv6hdr *iph;
179 		int poff;
180 
181 		if (!pskb_network_may_pull(skb, sizeof(*iph)))
182 			break;
183 		iph = ipv6_hdr(skb);
184 		poff = proto_ports_offset(iph->nexthdr);
185 		if (poff >= 0 &&
186 		    pskb_network_may_pull(skb, sizeof(*iph) + poff + 4)) {
187 			iph = ipv6_hdr(skb);
188 			return ntohs(*(__be16 *)((void *)iph + sizeof(*iph) +
189 						 poff + 2));
190 		}
191 		break;
192 	}
193 	}
194 
195 	return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol;
196 }
197 
198 static u32 flow_get_iif(const struct sk_buff *skb)
199 {
200 	return skb->skb_iif;
201 }
202 
203 static u32 flow_get_priority(const struct sk_buff *skb)
204 {
205 	return skb->priority;
206 }
207 
208 static u32 flow_get_mark(const struct sk_buff *skb)
209 {
210 	return skb->mark;
211 }
212 
213 static u32 flow_get_nfct(const struct sk_buff *skb)
214 {
215 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
216 	return addr_fold(skb->nfct);
217 #else
218 	return 0;
219 #endif
220 }
221 
222 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
223 #define CTTUPLE(skb, member)						\
224 ({									\
225 	enum ip_conntrack_info ctinfo;					\
226 	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);			\
227 	if (ct == NULL)							\
228 		goto fallback;						\
229 	ct->tuplehash[CTINFO2DIR(ctinfo)].tuple.member;			\
230 })
231 #else
232 #define CTTUPLE(skb, member)						\
233 ({									\
234 	goto fallback;							\
235 	0;								\
236 })
237 #endif
238 
239 static u32 flow_get_nfct_src(struct sk_buff *skb)
240 {
241 	switch (skb->protocol) {
242 	case htons(ETH_P_IP):
243 		return ntohl(CTTUPLE(skb, src.u3.ip));
244 	case htons(ETH_P_IPV6):
245 		return ntohl(CTTUPLE(skb, src.u3.ip6[3]));
246 	}
247 fallback:
248 	return flow_get_src(skb);
249 }
250 
251 static u32 flow_get_nfct_dst(struct sk_buff *skb)
252 {
253 	switch (skb->protocol) {
254 	case htons(ETH_P_IP):
255 		return ntohl(CTTUPLE(skb, dst.u3.ip));
256 	case htons(ETH_P_IPV6):
257 		return ntohl(CTTUPLE(skb, dst.u3.ip6[3]));
258 	}
259 fallback:
260 	return flow_get_dst(skb);
261 }
262 
263 static u32 flow_get_nfct_proto_src(struct sk_buff *skb)
264 {
265 	return ntohs(CTTUPLE(skb, src.u.all));
266 fallback:
267 	return flow_get_proto_src(skb);
268 }
269 
270 static u32 flow_get_nfct_proto_dst(struct sk_buff *skb)
271 {
272 	return ntohs(CTTUPLE(skb, dst.u.all));
273 fallback:
274 	return flow_get_proto_dst(skb);
275 }
276 
277 static u32 flow_get_rtclassid(const struct sk_buff *skb)
278 {
279 #ifdef CONFIG_NET_CLS_ROUTE
280 	if (skb_dst(skb))
281 		return skb_dst(skb)->tclassid;
282 #endif
283 	return 0;
284 }
285 
286 static u32 flow_get_skuid(const struct sk_buff *skb)
287 {
288 	if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file)
289 		return skb->sk->sk_socket->file->f_cred->fsuid;
290 	return 0;
291 }
292 
293 static u32 flow_get_skgid(const struct sk_buff *skb)
294 {
295 	if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file)
296 		return skb->sk->sk_socket->file->f_cred->fsgid;
297 	return 0;
298 }
299 
300 static u32 flow_get_vlan_tag(const struct sk_buff *skb)
301 {
302 	u16 uninitialized_var(tag);
303 
304 	if (vlan_get_tag(skb, &tag) < 0)
305 		return 0;
306 	return tag & VLAN_VID_MASK;
307 }
308 
309 static u32 flow_get_rxhash(struct sk_buff *skb)
310 {
311 	return skb_get_rxhash(skb);
312 }
313 
314 static u32 flow_key_get(struct sk_buff *skb, int key)
315 {
316 	switch (key) {
317 	case FLOW_KEY_SRC:
318 		return flow_get_src(skb);
319 	case FLOW_KEY_DST:
320 		return flow_get_dst(skb);
321 	case FLOW_KEY_PROTO:
322 		return flow_get_proto(skb);
323 	case FLOW_KEY_PROTO_SRC:
324 		return flow_get_proto_src(skb);
325 	case FLOW_KEY_PROTO_DST:
326 		return flow_get_proto_dst(skb);
327 	case FLOW_KEY_IIF:
328 		return flow_get_iif(skb);
329 	case FLOW_KEY_PRIORITY:
330 		return flow_get_priority(skb);
331 	case FLOW_KEY_MARK:
332 		return flow_get_mark(skb);
333 	case FLOW_KEY_NFCT:
334 		return flow_get_nfct(skb);
335 	case FLOW_KEY_NFCT_SRC:
336 		return flow_get_nfct_src(skb);
337 	case FLOW_KEY_NFCT_DST:
338 		return flow_get_nfct_dst(skb);
339 	case FLOW_KEY_NFCT_PROTO_SRC:
340 		return flow_get_nfct_proto_src(skb);
341 	case FLOW_KEY_NFCT_PROTO_DST:
342 		return flow_get_nfct_proto_dst(skb);
343 	case FLOW_KEY_RTCLASSID:
344 		return flow_get_rtclassid(skb);
345 	case FLOW_KEY_SKUID:
346 		return flow_get_skuid(skb);
347 	case FLOW_KEY_SKGID:
348 		return flow_get_skgid(skb);
349 	case FLOW_KEY_VLAN_TAG:
350 		return flow_get_vlan_tag(skb);
351 	case FLOW_KEY_RXHASH:
352 		return flow_get_rxhash(skb);
353 	default:
354 		WARN_ON(1);
355 		return 0;
356 	}
357 }
358 
359 static int flow_classify(struct sk_buff *skb, struct tcf_proto *tp,
360 			 struct tcf_result *res)
361 {
362 	struct flow_head *head = tp->root;
363 	struct flow_filter *f;
364 	u32 keymask;
365 	u32 classid;
366 	unsigned int n, key;
367 	int r;
368 
369 	list_for_each_entry(f, &head->filters, list) {
370 		u32 keys[f->nkeys];
371 
372 		if (!tcf_em_tree_match(skb, &f->ematches, NULL))
373 			continue;
374 
375 		keymask = f->keymask;
376 
377 		for (n = 0; n < f->nkeys; n++) {
378 			key = ffs(keymask) - 1;
379 			keymask &= ~(1 << key);
380 			keys[n] = flow_key_get(skb, key);
381 		}
382 
383 		if (f->mode == FLOW_MODE_HASH)
384 			classid = jhash2(keys, f->nkeys, f->hashrnd);
385 		else {
386 			classid = keys[0];
387 			classid = (classid & f->mask) ^ f->xor;
388 			classid = (classid >> f->rshift) + f->addend;
389 		}
390 
391 		if (f->divisor)
392 			classid %= f->divisor;
393 
394 		res->class   = 0;
395 		res->classid = TC_H_MAKE(f->baseclass, f->baseclass + classid);
396 
397 		r = tcf_exts_exec(skb, &f->exts, res);
398 		if (r < 0)
399 			continue;
400 		return r;
401 	}
402 	return -1;
403 }
404 
405 static void flow_perturbation(unsigned long arg)
406 {
407 	struct flow_filter *f = (struct flow_filter *)arg;
408 
409 	get_random_bytes(&f->hashrnd, 4);
410 	if (f->perturb_period)
411 		mod_timer(&f->perturb_timer, jiffies + f->perturb_period);
412 }
413 
414 static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = {
415 	[TCA_FLOW_KEYS]		= { .type = NLA_U32 },
416 	[TCA_FLOW_MODE]		= { .type = NLA_U32 },
417 	[TCA_FLOW_BASECLASS]	= { .type = NLA_U32 },
418 	[TCA_FLOW_RSHIFT]	= { .type = NLA_U32 },
419 	[TCA_FLOW_ADDEND]	= { .type = NLA_U32 },
420 	[TCA_FLOW_MASK]		= { .type = NLA_U32 },
421 	[TCA_FLOW_XOR]		= { .type = NLA_U32 },
422 	[TCA_FLOW_DIVISOR]	= { .type = NLA_U32 },
423 	[TCA_FLOW_ACT]		= { .type = NLA_NESTED },
424 	[TCA_FLOW_POLICE]	= { .type = NLA_NESTED },
425 	[TCA_FLOW_EMATCHES]	= { .type = NLA_NESTED },
426 	[TCA_FLOW_PERTURB]	= { .type = NLA_U32 },
427 };
428 
429 static int flow_change(struct tcf_proto *tp, unsigned long base,
430 		       u32 handle, struct nlattr **tca,
431 		       unsigned long *arg)
432 {
433 	struct flow_head *head = tp->root;
434 	struct flow_filter *f;
435 	struct nlattr *opt = tca[TCA_OPTIONS];
436 	struct nlattr *tb[TCA_FLOW_MAX + 1];
437 	struct tcf_exts e;
438 	struct tcf_ematch_tree t;
439 	unsigned int nkeys = 0;
440 	unsigned int perturb_period = 0;
441 	u32 baseclass = 0;
442 	u32 keymask = 0;
443 	u32 mode;
444 	int err;
445 
446 	if (opt == NULL)
447 		return -EINVAL;
448 
449 	err = nla_parse_nested(tb, TCA_FLOW_MAX, opt, flow_policy);
450 	if (err < 0)
451 		return err;
452 
453 	if (tb[TCA_FLOW_BASECLASS]) {
454 		baseclass = nla_get_u32(tb[TCA_FLOW_BASECLASS]);
455 		if (TC_H_MIN(baseclass) == 0)
456 			return -EINVAL;
457 	}
458 
459 	if (tb[TCA_FLOW_KEYS]) {
460 		keymask = nla_get_u32(tb[TCA_FLOW_KEYS]);
461 
462 		nkeys = hweight32(keymask);
463 		if (nkeys == 0)
464 			return -EINVAL;
465 
466 		if (fls(keymask) - 1 > FLOW_KEY_MAX)
467 			return -EOPNOTSUPP;
468 	}
469 
470 	err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &flow_ext_map);
471 	if (err < 0)
472 		return err;
473 
474 	err = tcf_em_tree_validate(tp, tb[TCA_FLOW_EMATCHES], &t);
475 	if (err < 0)
476 		goto err1;
477 
478 	f = (struct flow_filter *)*arg;
479 	if (f != NULL) {
480 		err = -EINVAL;
481 		if (f->handle != handle && handle)
482 			goto err2;
483 
484 		mode = f->mode;
485 		if (tb[TCA_FLOW_MODE])
486 			mode = nla_get_u32(tb[TCA_FLOW_MODE]);
487 		if (mode != FLOW_MODE_HASH && nkeys > 1)
488 			goto err2;
489 
490 		if (mode == FLOW_MODE_HASH)
491 			perturb_period = f->perturb_period;
492 		if (tb[TCA_FLOW_PERTURB]) {
493 			if (mode != FLOW_MODE_HASH)
494 				goto err2;
495 			perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
496 		}
497 	} else {
498 		err = -EINVAL;
499 		if (!handle)
500 			goto err2;
501 		if (!tb[TCA_FLOW_KEYS])
502 			goto err2;
503 
504 		mode = FLOW_MODE_MAP;
505 		if (tb[TCA_FLOW_MODE])
506 			mode = nla_get_u32(tb[TCA_FLOW_MODE]);
507 		if (mode != FLOW_MODE_HASH && nkeys > 1)
508 			goto err2;
509 
510 		if (tb[TCA_FLOW_PERTURB]) {
511 			if (mode != FLOW_MODE_HASH)
512 				goto err2;
513 			perturb_period = nla_get_u32(tb[TCA_FLOW_PERTURB]) * HZ;
514 		}
515 
516 		if (TC_H_MAJ(baseclass) == 0)
517 			baseclass = TC_H_MAKE(tp->q->handle, baseclass);
518 		if (TC_H_MIN(baseclass) == 0)
519 			baseclass = TC_H_MAKE(baseclass, 1);
520 
521 		err = -ENOBUFS;
522 		f = kzalloc(sizeof(*f), GFP_KERNEL);
523 		if (f == NULL)
524 			goto err2;
525 
526 		f->handle = handle;
527 		f->mask	  = ~0U;
528 
529 		get_random_bytes(&f->hashrnd, 4);
530 		f->perturb_timer.function = flow_perturbation;
531 		f->perturb_timer.data = (unsigned long)f;
532 		init_timer_deferrable(&f->perturb_timer);
533 	}
534 
535 	tcf_exts_change(tp, &f->exts, &e);
536 	tcf_em_tree_change(tp, &f->ematches, &t);
537 
538 	tcf_tree_lock(tp);
539 
540 	if (tb[TCA_FLOW_KEYS]) {
541 		f->keymask = keymask;
542 		f->nkeys   = nkeys;
543 	}
544 
545 	f->mode = mode;
546 
547 	if (tb[TCA_FLOW_MASK])
548 		f->mask = nla_get_u32(tb[TCA_FLOW_MASK]);
549 	if (tb[TCA_FLOW_XOR])
550 		f->xor = nla_get_u32(tb[TCA_FLOW_XOR]);
551 	if (tb[TCA_FLOW_RSHIFT])
552 		f->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]);
553 	if (tb[TCA_FLOW_ADDEND])
554 		f->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]);
555 
556 	if (tb[TCA_FLOW_DIVISOR])
557 		f->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]);
558 	if (baseclass)
559 		f->baseclass = baseclass;
560 
561 	f->perturb_period = perturb_period;
562 	del_timer(&f->perturb_timer);
563 	if (perturb_period)
564 		mod_timer(&f->perturb_timer, jiffies + perturb_period);
565 
566 	if (*arg == 0)
567 		list_add_tail(&f->list, &head->filters);
568 
569 	tcf_tree_unlock(tp);
570 
571 	*arg = (unsigned long)f;
572 	return 0;
573 
574 err2:
575 	tcf_em_tree_destroy(tp, &t);
576 err1:
577 	tcf_exts_destroy(tp, &e);
578 	return err;
579 }
580 
581 static void flow_destroy_filter(struct tcf_proto *tp, struct flow_filter *f)
582 {
583 	del_timer_sync(&f->perturb_timer);
584 	tcf_exts_destroy(tp, &f->exts);
585 	tcf_em_tree_destroy(tp, &f->ematches);
586 	kfree(f);
587 }
588 
589 static int flow_delete(struct tcf_proto *tp, unsigned long arg)
590 {
591 	struct flow_filter *f = (struct flow_filter *)arg;
592 
593 	tcf_tree_lock(tp);
594 	list_del(&f->list);
595 	tcf_tree_unlock(tp);
596 	flow_destroy_filter(tp, f);
597 	return 0;
598 }
599 
600 static int flow_init(struct tcf_proto *tp)
601 {
602 	struct flow_head *head;
603 
604 	head = kzalloc(sizeof(*head), GFP_KERNEL);
605 	if (head == NULL)
606 		return -ENOBUFS;
607 	INIT_LIST_HEAD(&head->filters);
608 	tp->root = head;
609 	return 0;
610 }
611 
612 static void flow_destroy(struct tcf_proto *tp)
613 {
614 	struct flow_head *head = tp->root;
615 	struct flow_filter *f, *next;
616 
617 	list_for_each_entry_safe(f, next, &head->filters, list) {
618 		list_del(&f->list);
619 		flow_destroy_filter(tp, f);
620 	}
621 	kfree(head);
622 }
623 
624 static unsigned long flow_get(struct tcf_proto *tp, u32 handle)
625 {
626 	struct flow_head *head = tp->root;
627 	struct flow_filter *f;
628 
629 	list_for_each_entry(f, &head->filters, list)
630 		if (f->handle == handle)
631 			return (unsigned long)f;
632 	return 0;
633 }
634 
635 static void flow_put(struct tcf_proto *tp, unsigned long f)
636 {
637 }
638 
639 static int flow_dump(struct tcf_proto *tp, unsigned long fh,
640 		     struct sk_buff *skb, struct tcmsg *t)
641 {
642 	struct flow_filter *f = (struct flow_filter *)fh;
643 	struct nlattr *nest;
644 
645 	if (f == NULL)
646 		return skb->len;
647 
648 	t->tcm_handle = f->handle;
649 
650 	nest = nla_nest_start(skb, TCA_OPTIONS);
651 	if (nest == NULL)
652 		goto nla_put_failure;
653 
654 	NLA_PUT_U32(skb, TCA_FLOW_KEYS, f->keymask);
655 	NLA_PUT_U32(skb, TCA_FLOW_MODE, f->mode);
656 
657 	if (f->mask != ~0 || f->xor != 0) {
658 		NLA_PUT_U32(skb, TCA_FLOW_MASK, f->mask);
659 		NLA_PUT_U32(skb, TCA_FLOW_XOR, f->xor);
660 	}
661 	if (f->rshift)
662 		NLA_PUT_U32(skb, TCA_FLOW_RSHIFT, f->rshift);
663 	if (f->addend)
664 		NLA_PUT_U32(skb, TCA_FLOW_ADDEND, f->addend);
665 
666 	if (f->divisor)
667 		NLA_PUT_U32(skb, TCA_FLOW_DIVISOR, f->divisor);
668 	if (f->baseclass)
669 		NLA_PUT_U32(skb, TCA_FLOW_BASECLASS, f->baseclass);
670 
671 	if (f->perturb_period)
672 		NLA_PUT_U32(skb, TCA_FLOW_PERTURB, f->perturb_period / HZ);
673 
674 	if (tcf_exts_dump(skb, &f->exts, &flow_ext_map) < 0)
675 		goto nla_put_failure;
676 #ifdef CONFIG_NET_EMATCH
677 	if (f->ematches.hdr.nmatches &&
678 	    tcf_em_tree_dump(skb, &f->ematches, TCA_FLOW_EMATCHES) < 0)
679 		goto nla_put_failure;
680 #endif
681 	nla_nest_end(skb, nest);
682 
683 	if (tcf_exts_dump_stats(skb, &f->exts, &flow_ext_map) < 0)
684 		goto nla_put_failure;
685 
686 	return skb->len;
687 
688 nla_put_failure:
689 	nlmsg_trim(skb, nest);
690 	return -1;
691 }
692 
693 static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg)
694 {
695 	struct flow_head *head = tp->root;
696 	struct flow_filter *f;
697 
698 	list_for_each_entry(f, &head->filters, list) {
699 		if (arg->count < arg->skip)
700 			goto skip;
701 		if (arg->fn(tp, (unsigned long)f, arg) < 0) {
702 			arg->stop = 1;
703 			break;
704 		}
705 skip:
706 		arg->count++;
707 	}
708 }
709 
710 static struct tcf_proto_ops cls_flow_ops __read_mostly = {
711 	.kind		= "flow",
712 	.classify	= flow_classify,
713 	.init		= flow_init,
714 	.destroy	= flow_destroy,
715 	.change		= flow_change,
716 	.delete		= flow_delete,
717 	.get		= flow_get,
718 	.put		= flow_put,
719 	.dump		= flow_dump,
720 	.walk		= flow_walk,
721 	.owner		= THIS_MODULE,
722 };
723 
724 static int __init cls_flow_init(void)
725 {
726 	return register_tcf_proto_ops(&cls_flow_ops);
727 }
728 
729 static void __exit cls_flow_exit(void)
730 {
731 	unregister_tcf_proto_ops(&cls_flow_ops);
732 }
733 
734 module_init(cls_flow_init);
735 module_exit(cls_flow_exit);
736 
737 MODULE_LICENSE("GPL");
738 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
739 MODULE_DESCRIPTION("TC flow classifier");
740