xref: /linux/net/sched/cls_u32.c (revision 83a37b3292f4aca799b355179ad6fbdd78a08e10)
1 /*
2  * net/sched/cls_u32.c	Ugly (or Universal) 32bit key Packet Classifier.
3  *
4  *		This program is free software; you can redistribute it and/or
5  *		modify it under the terms of the GNU General Public License
6  *		as published by the Free Software Foundation; either version
7  *		2 of the License, or (at your option) any later version.
8  *
9  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10  *
11  *	The filters are packed to hash tables of key nodes
12  *	with a set of 32bit key/mask pairs at every node.
13  *	Nodes reference next level hash tables etc.
14  *
15  *	This scheme is the best universal classifier I managed to
16  *	invent; it is not super-fast, but it is not slow (provided you
17  *	program it correctly), and general enough.  And its relative
18  *	speed grows as the number of rules becomes larger.
19  *
20  *	It seems that it represents the best middle point between
21  *	speed and manageability both by human and by machine.
22  *
23  *	It is especially useful for link sharing combined with QoS;
24  *	pure RSVP doesn't need such a general approach and can use
25  *	much simpler (and faster) schemes, sort of cls_rsvp.c.
26  *
27  *	JHS: We should remove the CONFIG_NET_CLS_IND from here
28  *	eventually when the meta match extension is made available
29  *
30  *	nfmark match added by Catalin(ux aka Dino) BOIE <catab at umbrella.ro>
31  */
32 
33 #include <linux/module.h>
34 #include <linux/slab.h>
35 #include <linux/types.h>
36 #include <linux/kernel.h>
37 #include <linux/string.h>
38 #include <linux/errno.h>
39 #include <linux/percpu.h>
40 #include <linux/rtnetlink.h>
41 #include <linux/skbuff.h>
42 #include <linux/bitmap.h>
43 #include <linux/netdevice.h>
44 #include <linux/hash.h>
45 #include <net/netlink.h>
46 #include <net/act_api.h>
47 #include <net/pkt_cls.h>
48 #include <linux/netdevice.h>
49 #include <linux/idr.h>
50 
51 struct tc_u_knode {
52 	struct tc_u_knode __rcu	*next;
53 	u32			handle;
54 	struct tc_u_hnode __rcu	*ht_up;
55 	struct tcf_exts		exts;
56 #ifdef CONFIG_NET_CLS_IND
57 	int			ifindex;
58 #endif
59 	u8			fshift;
60 	struct tcf_result	res;
61 	struct tc_u_hnode __rcu	*ht_down;
62 #ifdef CONFIG_CLS_U32_PERF
63 	struct tc_u32_pcnt __percpu *pf;
64 #endif
65 	u32			flags;
66 #ifdef CONFIG_CLS_U32_MARK
67 	u32			val;
68 	u32			mask;
69 	u32 __percpu		*pcpu_success;
70 #endif
71 	struct tcf_proto	*tp;
72 	struct rcu_head		rcu;
73 	/* The 'sel' field MUST be the last field in structure to allow for
74 	 * tc_u32_keys allocated at end of structure.
75 	 */
76 	struct tc_u32_sel	sel;
77 };
78 
79 struct tc_u_hnode {
80 	struct tc_u_hnode __rcu	*next;
81 	u32			handle;
82 	u32			prio;
83 	struct tc_u_common	*tp_c;
84 	int			refcnt;
85 	unsigned int		divisor;
86 	struct idr		handle_idr;
87 	struct rcu_head		rcu;
88 	/* The 'ht' field MUST be the last field in structure to allow for
89 	 * more entries allocated at end of structure.
90 	 */
91 	struct tc_u_knode __rcu	*ht[1];
92 };
93 
94 struct tc_u_common {
95 	struct tc_u_hnode __rcu	*hlist;
96 	struct tcf_block	*block;
97 	int			refcnt;
98 	struct idr		handle_idr;
99 	struct hlist_node	hnode;
100 	struct rcu_head		rcu;
101 };
102 
103 static inline unsigned int u32_hash_fold(__be32 key,
104 					 const struct tc_u32_sel *sel,
105 					 u8 fshift)
106 {
107 	unsigned int h = ntohl(key & sel->hmask) >> fshift;
108 
109 	return h;
110 }
111 
112 static int u32_classify(struct sk_buff *skb, const struct tcf_proto *tp,
113 			struct tcf_result *res)
114 {
115 	struct {
116 		struct tc_u_knode *knode;
117 		unsigned int	  off;
118 	} stack[TC_U32_MAXDEPTH];
119 
120 	struct tc_u_hnode *ht = rcu_dereference_bh(tp->root);
121 	unsigned int off = skb_network_offset(skb);
122 	struct tc_u_knode *n;
123 	int sdepth = 0;
124 	int off2 = 0;
125 	int sel = 0;
126 #ifdef CONFIG_CLS_U32_PERF
127 	int j;
128 #endif
129 	int i, r;
130 
131 next_ht:
132 	n = rcu_dereference_bh(ht->ht[sel]);
133 
134 next_knode:
135 	if (n) {
136 		struct tc_u32_key *key = n->sel.keys;
137 
138 #ifdef CONFIG_CLS_U32_PERF
139 		__this_cpu_inc(n->pf->rcnt);
140 		j = 0;
141 #endif
142 
143 		if (tc_skip_sw(n->flags)) {
144 			n = rcu_dereference_bh(n->next);
145 			goto next_knode;
146 		}
147 
148 #ifdef CONFIG_CLS_U32_MARK
149 		if ((skb->mark & n->mask) != n->val) {
150 			n = rcu_dereference_bh(n->next);
151 			goto next_knode;
152 		} else {
153 			__this_cpu_inc(*n->pcpu_success);
154 		}
155 #endif
156 
157 		for (i = n->sel.nkeys; i > 0; i--, key++) {
158 			int toff = off + key->off + (off2 & key->offmask);
159 			__be32 *data, hdata;
160 
161 			if (skb_headroom(skb) + toff > INT_MAX)
162 				goto out;
163 
164 			data = skb_header_pointer(skb, toff, 4, &hdata);
165 			if (!data)
166 				goto out;
167 			if ((*data ^ key->val) & key->mask) {
168 				n = rcu_dereference_bh(n->next);
169 				goto next_knode;
170 			}
171 #ifdef CONFIG_CLS_U32_PERF
172 			__this_cpu_inc(n->pf->kcnts[j]);
173 			j++;
174 #endif
175 		}
176 
177 		ht = rcu_dereference_bh(n->ht_down);
178 		if (!ht) {
179 check_terminal:
180 			if (n->sel.flags & TC_U32_TERMINAL) {
181 
182 				*res = n->res;
183 #ifdef CONFIG_NET_CLS_IND
184 				if (!tcf_match_indev(skb, n->ifindex)) {
185 					n = rcu_dereference_bh(n->next);
186 					goto next_knode;
187 				}
188 #endif
189 #ifdef CONFIG_CLS_U32_PERF
190 				__this_cpu_inc(n->pf->rhit);
191 #endif
192 				r = tcf_exts_exec(skb, &n->exts, res);
193 				if (r < 0) {
194 					n = rcu_dereference_bh(n->next);
195 					goto next_knode;
196 				}
197 
198 				return r;
199 			}
200 			n = rcu_dereference_bh(n->next);
201 			goto next_knode;
202 		}
203 
204 		/* PUSH */
205 		if (sdepth >= TC_U32_MAXDEPTH)
206 			goto deadloop;
207 		stack[sdepth].knode = n;
208 		stack[sdepth].off = off;
209 		sdepth++;
210 
211 		ht = rcu_dereference_bh(n->ht_down);
212 		sel = 0;
213 		if (ht->divisor) {
214 			__be32 *data, hdata;
215 
216 			data = skb_header_pointer(skb, off + n->sel.hoff, 4,
217 						  &hdata);
218 			if (!data)
219 				goto out;
220 			sel = ht->divisor & u32_hash_fold(*data, &n->sel,
221 							  n->fshift);
222 		}
223 		if (!(n->sel.flags & (TC_U32_VAROFFSET | TC_U32_OFFSET | TC_U32_EAT)))
224 			goto next_ht;
225 
226 		if (n->sel.flags & (TC_U32_OFFSET | TC_U32_VAROFFSET)) {
227 			off2 = n->sel.off + 3;
228 			if (n->sel.flags & TC_U32_VAROFFSET) {
229 				__be16 *data, hdata;
230 
231 				data = skb_header_pointer(skb,
232 							  off + n->sel.offoff,
233 							  2, &hdata);
234 				if (!data)
235 					goto out;
236 				off2 += ntohs(n->sel.offmask & *data) >>
237 					n->sel.offshift;
238 			}
239 			off2 &= ~3;
240 		}
241 		if (n->sel.flags & TC_U32_EAT) {
242 			off += off2;
243 			off2 = 0;
244 		}
245 
246 		if (off < skb->len)
247 			goto next_ht;
248 	}
249 
250 	/* POP */
251 	if (sdepth--) {
252 		n = stack[sdepth].knode;
253 		ht = rcu_dereference_bh(n->ht_up);
254 		off = stack[sdepth].off;
255 		goto check_terminal;
256 	}
257 out:
258 	return -1;
259 
260 deadloop:
261 	net_warn_ratelimited("cls_u32: dead loop\n");
262 	return -1;
263 }
264 
265 static struct tc_u_hnode *u32_lookup_ht(struct tc_u_common *tp_c, u32 handle)
266 {
267 	struct tc_u_hnode *ht;
268 
269 	for (ht = rtnl_dereference(tp_c->hlist);
270 	     ht;
271 	     ht = rtnl_dereference(ht->next))
272 		if (ht->handle == handle)
273 			break;
274 
275 	return ht;
276 }
277 
278 static struct tc_u_knode *u32_lookup_key(struct tc_u_hnode *ht, u32 handle)
279 {
280 	unsigned int sel;
281 	struct tc_u_knode *n = NULL;
282 
283 	sel = TC_U32_HASH(handle);
284 	if (sel > ht->divisor)
285 		goto out;
286 
287 	for (n = rtnl_dereference(ht->ht[sel]);
288 	     n;
289 	     n = rtnl_dereference(n->next))
290 		if (n->handle == handle)
291 			break;
292 out:
293 	return n;
294 }
295 
296 
297 static void *u32_get(struct tcf_proto *tp, u32 handle)
298 {
299 	struct tc_u_hnode *ht;
300 	struct tc_u_common *tp_c = tp->data;
301 
302 	if (TC_U32_HTID(handle) == TC_U32_ROOT)
303 		ht = rtnl_dereference(tp->root);
304 	else
305 		ht = u32_lookup_ht(tp_c, TC_U32_HTID(handle));
306 
307 	if (!ht)
308 		return NULL;
309 
310 	if (TC_U32_KEY(handle) == 0)
311 		return ht;
312 
313 	return u32_lookup_key(ht, handle);
314 }
315 
316 static u32 gen_new_htid(struct tc_u_common *tp_c, struct tc_u_hnode *ptr)
317 {
318 	unsigned long idr_index;
319 	int err;
320 
321 	/* This is only used inside rtnl lock it is safe to increment
322 	 * without read _copy_ update semantics
323 	 */
324 	err = idr_alloc_ext(&tp_c->handle_idr, ptr, &idr_index,
325 			    1, 0x7FF, GFP_KERNEL);
326 	if (err)
327 		return 0;
328 	return (u32)(idr_index | 0x800) << 20;
329 }
330 
331 static struct hlist_head *tc_u_common_hash;
332 
333 #define U32_HASH_SHIFT 10
334 #define U32_HASH_SIZE (1 << U32_HASH_SHIFT)
335 
336 static unsigned int tc_u_hash(const struct tcf_proto *tp)
337 {
338 	return hash_64((u64) tp->chain->block, U32_HASH_SHIFT);
339 }
340 
341 static struct tc_u_common *tc_u_common_find(const struct tcf_proto *tp)
342 {
343 	struct tc_u_common *tc;
344 	unsigned int h;
345 
346 	h = tc_u_hash(tp);
347 	hlist_for_each_entry(tc, &tc_u_common_hash[h], hnode) {
348 		if (tc->block == tp->chain->block)
349 			return tc;
350 	}
351 	return NULL;
352 }
353 
354 static int u32_init(struct tcf_proto *tp)
355 {
356 	struct tc_u_hnode *root_ht;
357 	struct tc_u_common *tp_c;
358 	unsigned int h;
359 
360 	tp_c = tc_u_common_find(tp);
361 
362 	root_ht = kzalloc(sizeof(*root_ht), GFP_KERNEL);
363 	if (root_ht == NULL)
364 		return -ENOBUFS;
365 
366 	root_ht->refcnt++;
367 	root_ht->handle = tp_c ? gen_new_htid(tp_c, root_ht) : 0x80000000;
368 	root_ht->prio = tp->prio;
369 	idr_init(&root_ht->handle_idr);
370 
371 	if (tp_c == NULL) {
372 		tp_c = kzalloc(sizeof(*tp_c), GFP_KERNEL);
373 		if (tp_c == NULL) {
374 			kfree(root_ht);
375 			return -ENOBUFS;
376 		}
377 		tp_c->block = tp->chain->block;
378 		INIT_HLIST_NODE(&tp_c->hnode);
379 		idr_init(&tp_c->handle_idr);
380 
381 		h = tc_u_hash(tp);
382 		hlist_add_head(&tp_c->hnode, &tc_u_common_hash[h]);
383 	}
384 
385 	tp_c->refcnt++;
386 	RCU_INIT_POINTER(root_ht->next, tp_c->hlist);
387 	rcu_assign_pointer(tp_c->hlist, root_ht);
388 	root_ht->tp_c = tp_c;
389 
390 	rcu_assign_pointer(tp->root, root_ht);
391 	tp->data = tp_c;
392 	return 0;
393 }
394 
395 static int u32_destroy_key(struct tcf_proto *tp, struct tc_u_knode *n,
396 			   bool free_pf)
397 {
398 	tcf_exts_destroy(&n->exts);
399 	if (n->ht_down)
400 		n->ht_down->refcnt--;
401 #ifdef CONFIG_CLS_U32_PERF
402 	if (free_pf)
403 		free_percpu(n->pf);
404 #endif
405 #ifdef CONFIG_CLS_U32_MARK
406 	if (free_pf)
407 		free_percpu(n->pcpu_success);
408 #endif
409 	kfree(n);
410 	return 0;
411 }
412 
413 /* u32_delete_key_rcu should be called when free'ing a copied
414  * version of a tc_u_knode obtained from u32_init_knode(). When
415  * copies are obtained from u32_init_knode() the statistics are
416  * shared between the old and new copies to allow readers to
417  * continue to update the statistics during the copy. To support
418  * this the u32_delete_key_rcu variant does not free the percpu
419  * statistics.
420  */
421 static void u32_delete_key_rcu(struct rcu_head *rcu)
422 {
423 	struct tc_u_knode *key = container_of(rcu, struct tc_u_knode, rcu);
424 
425 	u32_destroy_key(key->tp, key, false);
426 }
427 
428 /* u32_delete_key_freepf_rcu is the rcu callback variant
429  * that free's the entire structure including the statistics
430  * percpu variables. Only use this if the key is not a copy
431  * returned by u32_init_knode(). See u32_delete_key_rcu()
432  * for the variant that should be used with keys return from
433  * u32_init_knode()
434  */
435 static void u32_delete_key_freepf_rcu(struct rcu_head *rcu)
436 {
437 	struct tc_u_knode *key = container_of(rcu, struct tc_u_knode, rcu);
438 
439 	u32_destroy_key(key->tp, key, true);
440 }
441 
442 static int u32_delete_key(struct tcf_proto *tp, struct tc_u_knode *key)
443 {
444 	struct tc_u_knode __rcu **kp;
445 	struct tc_u_knode *pkp;
446 	struct tc_u_hnode *ht = rtnl_dereference(key->ht_up);
447 
448 	if (ht) {
449 		kp = &ht->ht[TC_U32_HASH(key->handle)];
450 		for (pkp = rtnl_dereference(*kp); pkp;
451 		     kp = &pkp->next, pkp = rtnl_dereference(*kp)) {
452 			if (pkp == key) {
453 				RCU_INIT_POINTER(*kp, key->next);
454 
455 				tcf_unbind_filter(tp, &key->res);
456 				call_rcu(&key->rcu, u32_delete_key_freepf_rcu);
457 				return 0;
458 			}
459 		}
460 	}
461 	WARN_ON(1);
462 	return 0;
463 }
464 
465 static void u32_remove_hw_knode(struct tcf_proto *tp, u32 handle)
466 {
467 	struct net_device *dev = tp->q->dev_queue->dev;
468 	struct tc_cls_u32_offload cls_u32 = {};
469 
470 	if (!tc_should_offload(dev, 0))
471 		return;
472 
473 	tc_cls_common_offload_init(&cls_u32.common, tp);
474 	cls_u32.command = TC_CLSU32_DELETE_KNODE;
475 	cls_u32.knode.handle = handle;
476 
477 	dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_CLSU32, &cls_u32);
478 }
479 
480 static int u32_replace_hw_hnode(struct tcf_proto *tp, struct tc_u_hnode *h,
481 				u32 flags)
482 {
483 	struct net_device *dev = tp->q->dev_queue->dev;
484 	struct tc_cls_u32_offload cls_u32 = {};
485 	int err;
486 
487 	if (!tc_should_offload(dev, flags))
488 		return tc_skip_sw(flags) ? -EINVAL : 0;
489 
490 	tc_cls_common_offload_init(&cls_u32.common, tp);
491 	cls_u32.command = TC_CLSU32_NEW_HNODE;
492 	cls_u32.hnode.divisor = h->divisor;
493 	cls_u32.hnode.handle = h->handle;
494 	cls_u32.hnode.prio = h->prio;
495 
496 	err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_CLSU32, &cls_u32);
497 	if (tc_skip_sw(flags))
498 		return err;
499 
500 	return 0;
501 }
502 
503 static void u32_clear_hw_hnode(struct tcf_proto *tp, struct tc_u_hnode *h)
504 {
505 	struct net_device *dev = tp->q->dev_queue->dev;
506 	struct tc_cls_u32_offload cls_u32 = {};
507 
508 	if (!tc_should_offload(dev, 0))
509 		return;
510 
511 	tc_cls_common_offload_init(&cls_u32.common, tp);
512 	cls_u32.command = TC_CLSU32_DELETE_HNODE;
513 	cls_u32.hnode.divisor = h->divisor;
514 	cls_u32.hnode.handle = h->handle;
515 	cls_u32.hnode.prio = h->prio;
516 
517 	dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_CLSU32, &cls_u32);
518 }
519 
520 static int u32_replace_hw_knode(struct tcf_proto *tp, struct tc_u_knode *n,
521 				u32 flags)
522 {
523 	struct net_device *dev = tp->q->dev_queue->dev;
524 	struct tc_cls_u32_offload cls_u32 = {};
525 	int err;
526 
527 	if (!tc_should_offload(dev, flags))
528 		return tc_skip_sw(flags) ? -EINVAL : 0;
529 
530 	tc_cls_common_offload_init(&cls_u32.common, tp);
531 	cls_u32.command = TC_CLSU32_REPLACE_KNODE;
532 	cls_u32.knode.handle = n->handle;
533 	cls_u32.knode.fshift = n->fshift;
534 #ifdef CONFIG_CLS_U32_MARK
535 	cls_u32.knode.val = n->val;
536 	cls_u32.knode.mask = n->mask;
537 #else
538 	cls_u32.knode.val = 0;
539 	cls_u32.knode.mask = 0;
540 #endif
541 	cls_u32.knode.sel = &n->sel;
542 	cls_u32.knode.exts = &n->exts;
543 	if (n->ht_down)
544 		cls_u32.knode.link_handle = n->ht_down->handle;
545 
546 	err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_CLSU32, &cls_u32);
547 
548 	if (!err)
549 		n->flags |= TCA_CLS_FLAGS_IN_HW;
550 
551 	if (tc_skip_sw(flags))
552 		return err;
553 
554 	return 0;
555 }
556 
557 static void u32_clear_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht)
558 {
559 	struct tc_u_knode *n;
560 	unsigned int h;
561 
562 	for (h = 0; h <= ht->divisor; h++) {
563 		while ((n = rtnl_dereference(ht->ht[h])) != NULL) {
564 			RCU_INIT_POINTER(ht->ht[h],
565 					 rtnl_dereference(n->next));
566 			tcf_unbind_filter(tp, &n->res);
567 			u32_remove_hw_knode(tp, n->handle);
568 			idr_remove_ext(&ht->handle_idr, n->handle);
569 			call_rcu(&n->rcu, u32_delete_key_freepf_rcu);
570 		}
571 	}
572 }
573 
574 static int u32_destroy_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht)
575 {
576 	struct tc_u_common *tp_c = tp->data;
577 	struct tc_u_hnode __rcu **hn;
578 	struct tc_u_hnode *phn;
579 
580 	WARN_ON(ht->refcnt);
581 
582 	u32_clear_hnode(tp, ht);
583 
584 	hn = &tp_c->hlist;
585 	for (phn = rtnl_dereference(*hn);
586 	     phn;
587 	     hn = &phn->next, phn = rtnl_dereference(*hn)) {
588 		if (phn == ht) {
589 			u32_clear_hw_hnode(tp, ht);
590 			idr_destroy(&ht->handle_idr);
591 			idr_remove_ext(&tp_c->handle_idr, ht->handle);
592 			RCU_INIT_POINTER(*hn, ht->next);
593 			kfree_rcu(ht, rcu);
594 			return 0;
595 		}
596 	}
597 
598 	return -ENOENT;
599 }
600 
601 static bool ht_empty(struct tc_u_hnode *ht)
602 {
603 	unsigned int h;
604 
605 	for (h = 0; h <= ht->divisor; h++)
606 		if (rcu_access_pointer(ht->ht[h]))
607 			return false;
608 
609 	return true;
610 }
611 
612 static void u32_destroy(struct tcf_proto *tp)
613 {
614 	struct tc_u_common *tp_c = tp->data;
615 	struct tc_u_hnode *root_ht = rtnl_dereference(tp->root);
616 
617 	WARN_ON(root_ht == NULL);
618 
619 	if (root_ht && --root_ht->refcnt == 0)
620 		u32_destroy_hnode(tp, root_ht);
621 
622 	if (--tp_c->refcnt == 0) {
623 		struct tc_u_hnode *ht;
624 
625 		hlist_del(&tp_c->hnode);
626 
627 		for (ht = rtnl_dereference(tp_c->hlist);
628 		     ht;
629 		     ht = rtnl_dereference(ht->next)) {
630 			ht->refcnt--;
631 			u32_clear_hnode(tp, ht);
632 		}
633 
634 		while ((ht = rtnl_dereference(tp_c->hlist)) != NULL) {
635 			RCU_INIT_POINTER(tp_c->hlist, ht->next);
636 			kfree_rcu(ht, rcu);
637 		}
638 
639 		idr_destroy(&tp_c->handle_idr);
640 		kfree(tp_c);
641 	}
642 
643 	tp->data = NULL;
644 }
645 
646 static int u32_delete(struct tcf_proto *tp, void *arg, bool *last)
647 {
648 	struct tc_u_hnode *ht = arg;
649 	struct tc_u_hnode *root_ht = rtnl_dereference(tp->root);
650 	struct tc_u_common *tp_c = tp->data;
651 	int ret = 0;
652 
653 	if (ht == NULL)
654 		goto out;
655 
656 	if (TC_U32_KEY(ht->handle)) {
657 		u32_remove_hw_knode(tp, ht->handle);
658 		ret = u32_delete_key(tp, (struct tc_u_knode *)ht);
659 		goto out;
660 	}
661 
662 	if (root_ht == ht)
663 		return -EINVAL;
664 
665 	if (ht->refcnt == 1) {
666 		ht->refcnt--;
667 		u32_destroy_hnode(tp, ht);
668 	} else {
669 		return -EBUSY;
670 	}
671 
672 out:
673 	*last = true;
674 	if (root_ht) {
675 		if (root_ht->refcnt > 1) {
676 			*last = false;
677 			goto ret;
678 		}
679 		if (root_ht->refcnt == 1) {
680 			if (!ht_empty(root_ht)) {
681 				*last = false;
682 				goto ret;
683 			}
684 		}
685 	}
686 
687 	if (tp_c->refcnt > 1) {
688 		*last = false;
689 		goto ret;
690 	}
691 
692 	if (tp_c->refcnt == 1) {
693 		struct tc_u_hnode *ht;
694 
695 		for (ht = rtnl_dereference(tp_c->hlist);
696 		     ht;
697 		     ht = rtnl_dereference(ht->next))
698 			if (!ht_empty(ht)) {
699 				*last = false;
700 				break;
701 			}
702 	}
703 
704 ret:
705 	return ret;
706 }
707 
708 static u32 gen_new_kid(struct tc_u_hnode *ht, u32 htid)
709 {
710 	unsigned long idr_index;
711 	u32 start = htid | 0x800;
712 	u32 max = htid | 0xFFF;
713 	u32 min = htid;
714 
715 	if (idr_alloc_ext(&ht->handle_idr, NULL, &idr_index,
716 			  start, max + 1, GFP_KERNEL)) {
717 		if (idr_alloc_ext(&ht->handle_idr, NULL, &idr_index,
718 				  min + 1, max + 1, GFP_KERNEL))
719 			return max;
720 	}
721 
722 	return (u32)idr_index;
723 }
724 
725 static const struct nla_policy u32_policy[TCA_U32_MAX + 1] = {
726 	[TCA_U32_CLASSID]	= { .type = NLA_U32 },
727 	[TCA_U32_HASH]		= { .type = NLA_U32 },
728 	[TCA_U32_LINK]		= { .type = NLA_U32 },
729 	[TCA_U32_DIVISOR]	= { .type = NLA_U32 },
730 	[TCA_U32_SEL]		= { .len = sizeof(struct tc_u32_sel) },
731 	[TCA_U32_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
732 	[TCA_U32_MARK]		= { .len = sizeof(struct tc_u32_mark) },
733 	[TCA_U32_FLAGS]		= { .type = NLA_U32 },
734 };
735 
736 static int u32_set_parms(struct net *net, struct tcf_proto *tp,
737 			 unsigned long base, struct tc_u_hnode *ht,
738 			 struct tc_u_knode *n, struct nlattr **tb,
739 			 struct nlattr *est, bool ovr)
740 {
741 	int err;
742 
743 	err = tcf_exts_validate(net, tp, tb, est, &n->exts, ovr);
744 	if (err < 0)
745 		return err;
746 
747 	if (tb[TCA_U32_LINK]) {
748 		u32 handle = nla_get_u32(tb[TCA_U32_LINK]);
749 		struct tc_u_hnode *ht_down = NULL, *ht_old;
750 
751 		if (TC_U32_KEY(handle))
752 			return -EINVAL;
753 
754 		if (handle) {
755 			ht_down = u32_lookup_ht(ht->tp_c, handle);
756 
757 			if (ht_down == NULL)
758 				return -EINVAL;
759 			ht_down->refcnt++;
760 		}
761 
762 		ht_old = rtnl_dereference(n->ht_down);
763 		rcu_assign_pointer(n->ht_down, ht_down);
764 
765 		if (ht_old)
766 			ht_old->refcnt--;
767 	}
768 	if (tb[TCA_U32_CLASSID]) {
769 		n->res.classid = nla_get_u32(tb[TCA_U32_CLASSID]);
770 		tcf_bind_filter(tp, &n->res, base);
771 	}
772 
773 #ifdef CONFIG_NET_CLS_IND
774 	if (tb[TCA_U32_INDEV]) {
775 		int ret;
776 		ret = tcf_change_indev(net, tb[TCA_U32_INDEV]);
777 		if (ret < 0)
778 			return -EINVAL;
779 		n->ifindex = ret;
780 	}
781 #endif
782 	return 0;
783 }
784 
785 static void u32_replace_knode(struct tcf_proto *tp, struct tc_u_common *tp_c,
786 			      struct tc_u_knode *n)
787 {
788 	struct tc_u_knode __rcu **ins;
789 	struct tc_u_knode *pins;
790 	struct tc_u_hnode *ht;
791 
792 	if (TC_U32_HTID(n->handle) == TC_U32_ROOT)
793 		ht = rtnl_dereference(tp->root);
794 	else
795 		ht = u32_lookup_ht(tp_c, TC_U32_HTID(n->handle));
796 
797 	ins = &ht->ht[TC_U32_HASH(n->handle)];
798 
799 	/* The node must always exist for it to be replaced if this is not the
800 	 * case then something went very wrong elsewhere.
801 	 */
802 	for (pins = rtnl_dereference(*ins); ;
803 	     ins = &pins->next, pins = rtnl_dereference(*ins))
804 		if (pins->handle == n->handle)
805 			break;
806 
807 	idr_replace_ext(&ht->handle_idr, n, n->handle);
808 	RCU_INIT_POINTER(n->next, pins->next);
809 	rcu_assign_pointer(*ins, n);
810 }
811 
812 static struct tc_u_knode *u32_init_knode(struct tcf_proto *tp,
813 					 struct tc_u_knode *n)
814 {
815 	struct tc_u_knode *new;
816 	struct tc_u32_sel *s = &n->sel;
817 
818 	new = kzalloc(sizeof(*n) + s->nkeys*sizeof(struct tc_u32_key),
819 		      GFP_KERNEL);
820 
821 	if (!new)
822 		return NULL;
823 
824 	RCU_INIT_POINTER(new->next, n->next);
825 	new->handle = n->handle;
826 	RCU_INIT_POINTER(new->ht_up, n->ht_up);
827 
828 #ifdef CONFIG_NET_CLS_IND
829 	new->ifindex = n->ifindex;
830 #endif
831 	new->fshift = n->fshift;
832 	new->res = n->res;
833 	new->flags = n->flags;
834 	RCU_INIT_POINTER(new->ht_down, n->ht_down);
835 
836 	/* bump reference count as long as we hold pointer to structure */
837 	if (new->ht_down)
838 		new->ht_down->refcnt++;
839 
840 #ifdef CONFIG_CLS_U32_PERF
841 	/* Statistics may be incremented by readers during update
842 	 * so we must keep them in tact. When the node is later destroyed
843 	 * a special destroy call must be made to not free the pf memory.
844 	 */
845 	new->pf = n->pf;
846 #endif
847 
848 #ifdef CONFIG_CLS_U32_MARK
849 	new->val = n->val;
850 	new->mask = n->mask;
851 	/* Similarly success statistics must be moved as pointers */
852 	new->pcpu_success = n->pcpu_success;
853 #endif
854 	new->tp = tp;
855 	memcpy(&new->sel, s, sizeof(*s) + s->nkeys*sizeof(struct tc_u32_key));
856 
857 	if (tcf_exts_init(&new->exts, TCA_U32_ACT, TCA_U32_POLICE)) {
858 		kfree(new);
859 		return NULL;
860 	}
861 
862 	return new;
863 }
864 
865 static int u32_change(struct net *net, struct sk_buff *in_skb,
866 		      struct tcf_proto *tp, unsigned long base, u32 handle,
867 		      struct nlattr **tca, void **arg, bool ovr)
868 {
869 	struct tc_u_common *tp_c = tp->data;
870 	struct tc_u_hnode *ht;
871 	struct tc_u_knode *n;
872 	struct tc_u32_sel *s;
873 	struct nlattr *opt = tca[TCA_OPTIONS];
874 	struct nlattr *tb[TCA_U32_MAX + 1];
875 	u32 htid, flags = 0;
876 	int err;
877 #ifdef CONFIG_CLS_U32_PERF
878 	size_t size;
879 #endif
880 
881 	if (opt == NULL)
882 		return handle ? -EINVAL : 0;
883 
884 	err = nla_parse_nested(tb, TCA_U32_MAX, opt, u32_policy, NULL);
885 	if (err < 0)
886 		return err;
887 
888 	if (tb[TCA_U32_FLAGS]) {
889 		flags = nla_get_u32(tb[TCA_U32_FLAGS]);
890 		if (!tc_flags_valid(flags))
891 			return -EINVAL;
892 	}
893 
894 	n = *arg;
895 	if (n) {
896 		struct tc_u_knode *new;
897 
898 		if (TC_U32_KEY(n->handle) == 0)
899 			return -EINVAL;
900 
901 		if (n->flags != flags)
902 			return -EINVAL;
903 
904 		new = u32_init_knode(tp, n);
905 		if (!new)
906 			return -ENOMEM;
907 
908 		err = u32_set_parms(net, tp, base,
909 				    rtnl_dereference(n->ht_up), new, tb,
910 				    tca[TCA_RATE], ovr);
911 
912 		if (err) {
913 			u32_destroy_key(tp, new, false);
914 			return err;
915 		}
916 
917 		err = u32_replace_hw_knode(tp, new, flags);
918 		if (err) {
919 			u32_destroy_key(tp, new, false);
920 			return err;
921 		}
922 
923 		if (!tc_in_hw(new->flags))
924 			new->flags |= TCA_CLS_FLAGS_NOT_IN_HW;
925 
926 		u32_replace_knode(tp, tp_c, new);
927 		tcf_unbind_filter(tp, &n->res);
928 		call_rcu(&n->rcu, u32_delete_key_rcu);
929 		return 0;
930 	}
931 
932 	if (tb[TCA_U32_DIVISOR]) {
933 		unsigned int divisor = nla_get_u32(tb[TCA_U32_DIVISOR]);
934 
935 		if (--divisor > 0x100)
936 			return -EINVAL;
937 		if (TC_U32_KEY(handle))
938 			return -EINVAL;
939 		ht = kzalloc(sizeof(*ht) + divisor*sizeof(void *), GFP_KERNEL);
940 		if (ht == NULL)
941 			return -ENOBUFS;
942 		if (handle == 0) {
943 			handle = gen_new_htid(tp->data, ht);
944 			if (handle == 0) {
945 				kfree(ht);
946 				return -ENOMEM;
947 			}
948 		} else {
949 			err = idr_alloc_ext(&tp_c->handle_idr, ht, NULL,
950 					    handle, handle + 1, GFP_KERNEL);
951 			if (err) {
952 				kfree(ht);
953 				return err;
954 			}
955 		}
956 		ht->tp_c = tp_c;
957 		ht->refcnt = 1;
958 		ht->divisor = divisor;
959 		ht->handle = handle;
960 		ht->prio = tp->prio;
961 		idr_init(&ht->handle_idr);
962 
963 		err = u32_replace_hw_hnode(tp, ht, flags);
964 		if (err) {
965 			idr_remove_ext(&tp_c->handle_idr, handle);
966 			kfree(ht);
967 			return err;
968 		}
969 
970 		RCU_INIT_POINTER(ht->next, tp_c->hlist);
971 		rcu_assign_pointer(tp_c->hlist, ht);
972 		*arg = ht;
973 
974 		return 0;
975 	}
976 
977 	if (tb[TCA_U32_HASH]) {
978 		htid = nla_get_u32(tb[TCA_U32_HASH]);
979 		if (TC_U32_HTID(htid) == TC_U32_ROOT) {
980 			ht = rtnl_dereference(tp->root);
981 			htid = ht->handle;
982 		} else {
983 			ht = u32_lookup_ht(tp->data, TC_U32_HTID(htid));
984 			if (ht == NULL)
985 				return -EINVAL;
986 		}
987 	} else {
988 		ht = rtnl_dereference(tp->root);
989 		htid = ht->handle;
990 	}
991 
992 	if (ht->divisor < TC_U32_HASH(htid))
993 		return -EINVAL;
994 
995 	if (handle) {
996 		if (TC_U32_HTID(handle) && TC_U32_HTID(handle^htid))
997 			return -EINVAL;
998 		handle = htid | TC_U32_NODE(handle);
999 		err = idr_alloc_ext(&ht->handle_idr, NULL, NULL,
1000 				    handle, handle + 1,
1001 				    GFP_KERNEL);
1002 		if (err)
1003 			return err;
1004 	} else
1005 		handle = gen_new_kid(ht, htid);
1006 
1007 	if (tb[TCA_U32_SEL] == NULL) {
1008 		err = -EINVAL;
1009 		goto erridr;
1010 	}
1011 
1012 	s = nla_data(tb[TCA_U32_SEL]);
1013 
1014 	n = kzalloc(sizeof(*n) + s->nkeys*sizeof(struct tc_u32_key), GFP_KERNEL);
1015 	if (n == NULL) {
1016 		err = -ENOBUFS;
1017 		goto erridr;
1018 	}
1019 
1020 #ifdef CONFIG_CLS_U32_PERF
1021 	size = sizeof(struct tc_u32_pcnt) + s->nkeys * sizeof(u64);
1022 	n->pf = __alloc_percpu(size, __alignof__(struct tc_u32_pcnt));
1023 	if (!n->pf) {
1024 		err = -ENOBUFS;
1025 		goto errfree;
1026 	}
1027 #endif
1028 
1029 	memcpy(&n->sel, s, sizeof(*s) + s->nkeys*sizeof(struct tc_u32_key));
1030 	RCU_INIT_POINTER(n->ht_up, ht);
1031 	n->handle = handle;
1032 	n->fshift = s->hmask ? ffs(ntohl(s->hmask)) - 1 : 0;
1033 	n->flags = flags;
1034 	n->tp = tp;
1035 
1036 	err = tcf_exts_init(&n->exts, TCA_U32_ACT, TCA_U32_POLICE);
1037 	if (err < 0)
1038 		goto errout;
1039 
1040 #ifdef CONFIG_CLS_U32_MARK
1041 	n->pcpu_success = alloc_percpu(u32);
1042 	if (!n->pcpu_success) {
1043 		err = -ENOMEM;
1044 		goto errout;
1045 	}
1046 
1047 	if (tb[TCA_U32_MARK]) {
1048 		struct tc_u32_mark *mark;
1049 
1050 		mark = nla_data(tb[TCA_U32_MARK]);
1051 		n->val = mark->val;
1052 		n->mask = mark->mask;
1053 	}
1054 #endif
1055 
1056 	err = u32_set_parms(net, tp, base, ht, n, tb, tca[TCA_RATE], ovr);
1057 	if (err == 0) {
1058 		struct tc_u_knode __rcu **ins;
1059 		struct tc_u_knode *pins;
1060 
1061 		err = u32_replace_hw_knode(tp, n, flags);
1062 		if (err)
1063 			goto errhw;
1064 
1065 		if (!tc_in_hw(n->flags))
1066 			n->flags |= TCA_CLS_FLAGS_NOT_IN_HW;
1067 
1068 		ins = &ht->ht[TC_U32_HASH(handle)];
1069 		for (pins = rtnl_dereference(*ins); pins;
1070 		     ins = &pins->next, pins = rtnl_dereference(*ins))
1071 			if (TC_U32_NODE(handle) < TC_U32_NODE(pins->handle))
1072 				break;
1073 
1074 		RCU_INIT_POINTER(n->next, pins);
1075 		rcu_assign_pointer(*ins, n);
1076 		*arg = n;
1077 		return 0;
1078 	}
1079 
1080 errhw:
1081 #ifdef CONFIG_CLS_U32_MARK
1082 	free_percpu(n->pcpu_success);
1083 #endif
1084 
1085 errout:
1086 	tcf_exts_destroy(&n->exts);
1087 #ifdef CONFIG_CLS_U32_PERF
1088 errfree:
1089 	free_percpu(n->pf);
1090 #endif
1091 	kfree(n);
1092 erridr:
1093 	idr_remove_ext(&ht->handle_idr, handle);
1094 	return err;
1095 }
1096 
1097 static void u32_walk(struct tcf_proto *tp, struct tcf_walker *arg)
1098 {
1099 	struct tc_u_common *tp_c = tp->data;
1100 	struct tc_u_hnode *ht;
1101 	struct tc_u_knode *n;
1102 	unsigned int h;
1103 
1104 	if (arg->stop)
1105 		return;
1106 
1107 	for (ht = rtnl_dereference(tp_c->hlist);
1108 	     ht;
1109 	     ht = rtnl_dereference(ht->next)) {
1110 		if (ht->prio != tp->prio)
1111 			continue;
1112 		if (arg->count >= arg->skip) {
1113 			if (arg->fn(tp, ht, arg) < 0) {
1114 				arg->stop = 1;
1115 				return;
1116 			}
1117 		}
1118 		arg->count++;
1119 		for (h = 0; h <= ht->divisor; h++) {
1120 			for (n = rtnl_dereference(ht->ht[h]);
1121 			     n;
1122 			     n = rtnl_dereference(n->next)) {
1123 				if (arg->count < arg->skip) {
1124 					arg->count++;
1125 					continue;
1126 				}
1127 				if (arg->fn(tp, n, arg) < 0) {
1128 					arg->stop = 1;
1129 					return;
1130 				}
1131 				arg->count++;
1132 			}
1133 		}
1134 	}
1135 }
1136 
1137 static void u32_bind_class(void *fh, u32 classid, unsigned long cl)
1138 {
1139 	struct tc_u_knode *n = fh;
1140 
1141 	if (n && n->res.classid == classid)
1142 		n->res.class = cl;
1143 }
1144 
1145 static int u32_dump(struct net *net, struct tcf_proto *tp, void *fh,
1146 		    struct sk_buff *skb, struct tcmsg *t)
1147 {
1148 	struct tc_u_knode *n = fh;
1149 	struct tc_u_hnode *ht_up, *ht_down;
1150 	struct nlattr *nest;
1151 
1152 	if (n == NULL)
1153 		return skb->len;
1154 
1155 	t->tcm_handle = n->handle;
1156 
1157 	nest = nla_nest_start(skb, TCA_OPTIONS);
1158 	if (nest == NULL)
1159 		goto nla_put_failure;
1160 
1161 	if (TC_U32_KEY(n->handle) == 0) {
1162 		struct tc_u_hnode *ht = fh;
1163 		u32 divisor = ht->divisor + 1;
1164 
1165 		if (nla_put_u32(skb, TCA_U32_DIVISOR, divisor))
1166 			goto nla_put_failure;
1167 	} else {
1168 #ifdef CONFIG_CLS_U32_PERF
1169 		struct tc_u32_pcnt *gpf;
1170 		int cpu;
1171 #endif
1172 
1173 		if (nla_put(skb, TCA_U32_SEL,
1174 			    sizeof(n->sel) + n->sel.nkeys*sizeof(struct tc_u32_key),
1175 			    &n->sel))
1176 			goto nla_put_failure;
1177 
1178 		ht_up = rtnl_dereference(n->ht_up);
1179 		if (ht_up) {
1180 			u32 htid = n->handle & 0xFFFFF000;
1181 			if (nla_put_u32(skb, TCA_U32_HASH, htid))
1182 				goto nla_put_failure;
1183 		}
1184 		if (n->res.classid &&
1185 		    nla_put_u32(skb, TCA_U32_CLASSID, n->res.classid))
1186 			goto nla_put_failure;
1187 
1188 		ht_down = rtnl_dereference(n->ht_down);
1189 		if (ht_down &&
1190 		    nla_put_u32(skb, TCA_U32_LINK, ht_down->handle))
1191 			goto nla_put_failure;
1192 
1193 		if (n->flags && nla_put_u32(skb, TCA_U32_FLAGS, n->flags))
1194 			goto nla_put_failure;
1195 
1196 #ifdef CONFIG_CLS_U32_MARK
1197 		if ((n->val || n->mask)) {
1198 			struct tc_u32_mark mark = {.val = n->val,
1199 						   .mask = n->mask,
1200 						   .success = 0};
1201 			int cpum;
1202 
1203 			for_each_possible_cpu(cpum) {
1204 				__u32 cnt = *per_cpu_ptr(n->pcpu_success, cpum);
1205 
1206 				mark.success += cnt;
1207 			}
1208 
1209 			if (nla_put(skb, TCA_U32_MARK, sizeof(mark), &mark))
1210 				goto nla_put_failure;
1211 		}
1212 #endif
1213 
1214 		if (tcf_exts_dump(skb, &n->exts) < 0)
1215 			goto nla_put_failure;
1216 
1217 #ifdef CONFIG_NET_CLS_IND
1218 		if (n->ifindex) {
1219 			struct net_device *dev;
1220 			dev = __dev_get_by_index(net, n->ifindex);
1221 			if (dev && nla_put_string(skb, TCA_U32_INDEV, dev->name))
1222 				goto nla_put_failure;
1223 		}
1224 #endif
1225 #ifdef CONFIG_CLS_U32_PERF
1226 		gpf = kzalloc(sizeof(struct tc_u32_pcnt) +
1227 			      n->sel.nkeys * sizeof(u64),
1228 			      GFP_KERNEL);
1229 		if (!gpf)
1230 			goto nla_put_failure;
1231 
1232 		for_each_possible_cpu(cpu) {
1233 			int i;
1234 			struct tc_u32_pcnt *pf = per_cpu_ptr(n->pf, cpu);
1235 
1236 			gpf->rcnt += pf->rcnt;
1237 			gpf->rhit += pf->rhit;
1238 			for (i = 0; i < n->sel.nkeys; i++)
1239 				gpf->kcnts[i] += pf->kcnts[i];
1240 		}
1241 
1242 		if (nla_put_64bit(skb, TCA_U32_PCNT,
1243 				  sizeof(struct tc_u32_pcnt) +
1244 				  n->sel.nkeys * sizeof(u64),
1245 				  gpf, TCA_U32_PAD)) {
1246 			kfree(gpf);
1247 			goto nla_put_failure;
1248 		}
1249 		kfree(gpf);
1250 #endif
1251 	}
1252 
1253 	nla_nest_end(skb, nest);
1254 
1255 	if (TC_U32_KEY(n->handle))
1256 		if (tcf_exts_dump_stats(skb, &n->exts) < 0)
1257 			goto nla_put_failure;
1258 	return skb->len;
1259 
1260 nla_put_failure:
1261 	nla_nest_cancel(skb, nest);
1262 	return -1;
1263 }
1264 
1265 static struct tcf_proto_ops cls_u32_ops __read_mostly = {
1266 	.kind		=	"u32",
1267 	.classify	=	u32_classify,
1268 	.init		=	u32_init,
1269 	.destroy	=	u32_destroy,
1270 	.get		=	u32_get,
1271 	.change		=	u32_change,
1272 	.delete		=	u32_delete,
1273 	.walk		=	u32_walk,
1274 	.dump		=	u32_dump,
1275 	.bind_class	=	u32_bind_class,
1276 	.owner		=	THIS_MODULE,
1277 };
1278 
1279 static int __init init_u32(void)
1280 {
1281 	int i, ret;
1282 
1283 	pr_info("u32 classifier\n");
1284 #ifdef CONFIG_CLS_U32_PERF
1285 	pr_info("    Performance counters on\n");
1286 #endif
1287 #ifdef CONFIG_NET_CLS_IND
1288 	pr_info("    input device check on\n");
1289 #endif
1290 #ifdef CONFIG_NET_CLS_ACT
1291 	pr_info("    Actions configured\n");
1292 #endif
1293 	tc_u_common_hash = kvmalloc_array(U32_HASH_SIZE,
1294 					  sizeof(struct hlist_head),
1295 					  GFP_KERNEL);
1296 	if (!tc_u_common_hash)
1297 		return -ENOMEM;
1298 
1299 	for (i = 0; i < U32_HASH_SIZE; i++)
1300 		INIT_HLIST_HEAD(&tc_u_common_hash[i]);
1301 
1302 	ret = register_tcf_proto_ops(&cls_u32_ops);
1303 	if (ret)
1304 		kvfree(tc_u_common_hash);
1305 	return ret;
1306 }
1307 
1308 static void __exit exit_u32(void)
1309 {
1310 	unregister_tcf_proto_ops(&cls_u32_ops);
1311 	kvfree(tc_u_common_hash);
1312 }
1313 
1314 module_init(init_u32)
1315 module_exit(exit_u32)
1316 MODULE_LICENSE("GPL");
1317