xref: /linux/net/sched/cls_route.c (revision 80d443e8876602be2c130f79c4de81e12e2a700d) 
1 /*
2  * net/sched/cls_route.c	ROUTE4 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 
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/errno.h>
18 #include <linux/skbuff.h>
19 #include <net/dst.h>
20 #include <net/route.h>
21 #include <net/netlink.h>
22 #include <net/act_api.h>
23 #include <net/pkt_cls.h>
24 
25 /*
26  * 1. For now we assume that route tags < 256.
27  *    It allows to use direct table lookups, instead of hash tables.
28  * 2. For now we assume that "from TAG" and "fromdev DEV" statements
29  *    are mutually  exclusive.
30  * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
31  */
32 struct route4_fastmap {
33 	struct route4_filter		*filter;
34 	u32				id;
35 	int				iif;
36 };
37 
38 struct route4_head {
39 	struct route4_fastmap		fastmap[16];
40 	struct route4_bucket __rcu	*table[256 + 1];
41 	struct rcu_head			rcu;
42 };
43 
44 struct route4_bucket {
45 	/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
46 	struct route4_filter __rcu	*ht[16 + 16 + 1];
47 	struct rcu_head			rcu;
48 };
49 
50 struct route4_filter {
51 	struct route4_filter __rcu	*next;
52 	u32			id;
53 	int			iif;
54 
55 	struct tcf_result	res;
56 	struct tcf_exts		exts;
57 	u32			handle;
58 	struct route4_bucket	*bkt;
59 	struct tcf_proto	*tp;
60 	struct rcu_head		rcu;
61 };
62 
63 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
64 
65 static inline int route4_fastmap_hash(u32 id, int iif)
66 {
67 	return id & 0xF;
68 }
69 
70 static DEFINE_SPINLOCK(fastmap_lock);
71 static void
72 route4_reset_fastmap(struct route4_head *head)
73 {
74 	spin_lock_bh(&fastmap_lock);
75 	memset(head->fastmap, 0, sizeof(head->fastmap));
76 	spin_unlock_bh(&fastmap_lock);
77 }
78 
79 static void
80 route4_set_fastmap(struct route4_head *head, u32 id, int iif,
81 		   struct route4_filter *f)
82 {
83 	int h = route4_fastmap_hash(id, iif);
84 
85 	/* fastmap updates must look atomic to aling id, iff, filter */
86 	spin_lock_bh(&fastmap_lock);
87 	head->fastmap[h].id = id;
88 	head->fastmap[h].iif = iif;
89 	head->fastmap[h].filter = f;
90 	spin_unlock_bh(&fastmap_lock);
91 }
92 
93 static inline int route4_hash_to(u32 id)
94 {
95 	return id & 0xFF;
96 }
97 
98 static inline int route4_hash_from(u32 id)
99 {
100 	return (id >> 16) & 0xF;
101 }
102 
103 static inline int route4_hash_iif(int iif)
104 {
105 	return 16 + ((iif >> 16) & 0xF);
106 }
107 
108 static inline int route4_hash_wild(void)
109 {
110 	return 32;
111 }
112 
113 #define ROUTE4_APPLY_RESULT()					\
114 {								\
115 	*res = f->res;						\
116 	if (tcf_exts_is_available(&f->exts)) {			\
117 		int r = tcf_exts_exec(skb, &f->exts, res);	\
118 		if (r < 0) {					\
119 			dont_cache = 1;				\
120 			continue;				\
121 		}						\
122 		return r;					\
123 	} else if (!dont_cache)					\
124 		route4_set_fastmap(head, id, iif, f);		\
125 	return 0;						\
126 }
127 
128 static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
129 			   struct tcf_result *res)
130 {
131 	struct route4_head *head = rcu_dereference_bh(tp->root);
132 	struct dst_entry *dst;
133 	struct route4_bucket *b;
134 	struct route4_filter *f;
135 	u32 id, h;
136 	int iif, dont_cache = 0;
137 
138 	dst = skb_dst(skb);
139 	if (!dst)
140 		goto failure;
141 
142 	id = dst->tclassid;
143 	if (head == NULL)
144 		goto old_method;
145 
146 	iif = inet_iif(skb);
147 
148 	h = route4_fastmap_hash(id, iif);
149 
150 	spin_lock(&fastmap_lock);
151 	if (id == head->fastmap[h].id &&
152 	    iif == head->fastmap[h].iif &&
153 	    (f = head->fastmap[h].filter) != NULL) {
154 		if (f == ROUTE4_FAILURE) {
155 			spin_unlock(&fastmap_lock);
156 			goto failure;
157 		}
158 
159 		*res = f->res;
160 		spin_unlock(&fastmap_lock);
161 		return 0;
162 	}
163 	spin_unlock(&fastmap_lock);
164 
165 	h = route4_hash_to(id);
166 
167 restart:
168 	b = rcu_dereference_bh(head->table[h]);
169 	if (b) {
170 		for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
171 		     f;
172 		     f = rcu_dereference_bh(f->next))
173 			if (f->id == id)
174 				ROUTE4_APPLY_RESULT();
175 
176 		for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
177 		     f;
178 		     f = rcu_dereference_bh(f->next))
179 			if (f->iif == iif)
180 				ROUTE4_APPLY_RESULT();
181 
182 		for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
183 		     f;
184 		     f = rcu_dereference_bh(f->next))
185 			ROUTE4_APPLY_RESULT();
186 	}
187 	if (h < 256) {
188 		h = 256;
189 		id &= ~0xFFFF;
190 		goto restart;
191 	}
192 
193 	if (!dont_cache)
194 		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
195 failure:
196 	return -1;
197 
198 old_method:
199 	if (id && (TC_H_MAJ(id) == 0 ||
200 		   !(TC_H_MAJ(id^tp->q->handle)))) {
201 		res->classid = id;
202 		res->class = 0;
203 		return 0;
204 	}
205 	return -1;
206 }
207 
208 static inline u32 to_hash(u32 id)
209 {
210 	u32 h = id & 0xFF;
211 
212 	if (id & 0x8000)
213 		h += 256;
214 	return h;
215 }
216 
217 static inline u32 from_hash(u32 id)
218 {
219 	id &= 0xFFFF;
220 	if (id == 0xFFFF)
221 		return 32;
222 	if (!(id & 0x8000)) {
223 		if (id > 255)
224 			return 256;
225 		return id & 0xF;
226 	}
227 	return 16 + (id & 0xF);
228 }
229 
230 static unsigned long route4_get(struct tcf_proto *tp, u32 handle)
231 {
232 	struct route4_head *head = rtnl_dereference(tp->root);
233 	struct route4_bucket *b;
234 	struct route4_filter *f;
235 	unsigned int h1, h2;
236 
237 	if (!head)
238 		return 0;
239 
240 	h1 = to_hash(handle);
241 	if (h1 > 256)
242 		return 0;
243 
244 	h2 = from_hash(handle >> 16);
245 	if (h2 > 32)
246 		return 0;
247 
248 	b = rtnl_dereference(head->table[h1]);
249 	if (b) {
250 		for (f = rtnl_dereference(b->ht[h2]);
251 		     f;
252 		     f = rtnl_dereference(f->next))
253 			if (f->handle == handle)
254 				return (unsigned long)f;
255 	}
256 	return 0;
257 }
258 
259 static int route4_init(struct tcf_proto *tp)
260 {
261 	struct route4_head *head;
262 
263 	head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
264 	if (head == NULL)
265 		return -ENOBUFS;
266 
267 	rcu_assign_pointer(tp->root, head);
268 	return 0;
269 }
270 
271 static void route4_delete_filter(struct rcu_head *head)
272 {
273 	struct route4_filter *f = container_of(head, struct route4_filter, rcu);
274 
275 	tcf_exts_destroy(&f->exts);
276 	kfree(f);
277 }
278 
279 static bool route4_destroy(struct tcf_proto *tp, bool force)
280 {
281 	struct route4_head *head = rtnl_dereference(tp->root);
282 	int h1, h2;
283 
284 	if (head == NULL)
285 		return true;
286 
287 	if (!force) {
288 		for (h1 = 0; h1 <= 256; h1++) {
289 			if (rcu_access_pointer(head->table[h1]))
290 				return false;
291 		}
292 	}
293 
294 	for (h1 = 0; h1 <= 256; h1++) {
295 		struct route4_bucket *b;
296 
297 		b = rtnl_dereference(head->table[h1]);
298 		if (b) {
299 			for (h2 = 0; h2 <= 32; h2++) {
300 				struct route4_filter *f;
301 
302 				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
303 					struct route4_filter *next;
304 
305 					next = rtnl_dereference(f->next);
306 					RCU_INIT_POINTER(b->ht[h2], next);
307 					tcf_unbind_filter(tp, &f->res);
308 					call_rcu(&f->rcu, route4_delete_filter);
309 				}
310 			}
311 			RCU_INIT_POINTER(head->table[h1], NULL);
312 			kfree_rcu(b, rcu);
313 		}
314 	}
315 	RCU_INIT_POINTER(tp->root, NULL);
316 	kfree_rcu(head, rcu);
317 	return true;
318 }
319 
320 static int route4_delete(struct tcf_proto *tp, unsigned long arg)
321 {
322 	struct route4_head *head = rtnl_dereference(tp->root);
323 	struct route4_filter *f = (struct route4_filter *)arg;
324 	struct route4_filter __rcu **fp;
325 	struct route4_filter *nf;
326 	struct route4_bucket *b;
327 	unsigned int h = 0;
328 	int i;
329 
330 	if (!head || !f)
331 		return -EINVAL;
332 
333 	h = f->handle;
334 	b = f->bkt;
335 
336 	fp = &b->ht[from_hash(h >> 16)];
337 	for (nf = rtnl_dereference(*fp); nf;
338 	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
339 		if (nf == f) {
340 			/* unlink it */
341 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
342 
343 			/* Remove any fastmap lookups that might ref filter
344 			 * notice we unlink'd the filter so we can't get it
345 			 * back in the fastmap.
346 			 */
347 			route4_reset_fastmap(head);
348 
349 			/* Delete it */
350 			tcf_unbind_filter(tp, &f->res);
351 			call_rcu(&f->rcu, route4_delete_filter);
352 
353 			/* Strip RTNL protected tree */
354 			for (i = 0; i <= 32; i++) {
355 				struct route4_filter *rt;
356 
357 				rt = rtnl_dereference(b->ht[i]);
358 				if (rt)
359 					return 0;
360 			}
361 
362 			/* OK, session has no flows */
363 			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
364 			kfree_rcu(b, rcu);
365 
366 			return 0;
367 		}
368 	}
369 	return 0;
370 }
371 
372 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
373 	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
374 	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
375 	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
376 	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
377 };
378 
379 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
380 			    unsigned long base, struct route4_filter *f,
381 			    u32 handle, struct route4_head *head,
382 			    struct nlattr **tb, struct nlattr *est, int new,
383 			    bool ovr)
384 {
385 	u32 id = 0, to = 0, nhandle = 0x8000;
386 	struct route4_filter *fp;
387 	unsigned int h1;
388 	struct route4_bucket *b;
389 	struct tcf_exts e;
390 	int err;
391 
392 	err = tcf_exts_init(&e, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
393 	if (err < 0)
394 		return err;
395 	err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
396 	if (err < 0)
397 		goto errout;
398 
399 	err = -EINVAL;
400 	if (tb[TCA_ROUTE4_TO]) {
401 		if (new && handle & 0x8000)
402 			goto errout;
403 		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
404 		if (to > 0xFF)
405 			goto errout;
406 		nhandle = to;
407 	}
408 
409 	if (tb[TCA_ROUTE4_FROM]) {
410 		if (tb[TCA_ROUTE4_IIF])
411 			goto errout;
412 		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
413 		if (id > 0xFF)
414 			goto errout;
415 		nhandle |= id << 16;
416 	} else if (tb[TCA_ROUTE4_IIF]) {
417 		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
418 		if (id > 0x7FFF)
419 			goto errout;
420 		nhandle |= (id | 0x8000) << 16;
421 	} else
422 		nhandle |= 0xFFFF << 16;
423 
424 	if (handle && new) {
425 		nhandle |= handle & 0x7F00;
426 		if (nhandle != handle)
427 			goto errout;
428 	}
429 
430 	h1 = to_hash(nhandle);
431 	b = rtnl_dereference(head->table[h1]);
432 	if (!b) {
433 		err = -ENOBUFS;
434 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
435 		if (b == NULL)
436 			goto errout;
437 
438 		rcu_assign_pointer(head->table[h1], b);
439 	} else {
440 		unsigned int h2 = from_hash(nhandle >> 16);
441 
442 		err = -EEXIST;
443 		for (fp = rtnl_dereference(b->ht[h2]);
444 		     fp;
445 		     fp = rtnl_dereference(fp->next))
446 			if (fp->handle == f->handle)
447 				goto errout;
448 	}
449 
450 	if (tb[TCA_ROUTE4_TO])
451 		f->id = to;
452 
453 	if (tb[TCA_ROUTE4_FROM])
454 		f->id = to | id<<16;
455 	else if (tb[TCA_ROUTE4_IIF])
456 		f->iif = id;
457 
458 	f->handle = nhandle;
459 	f->bkt = b;
460 	f->tp = tp;
461 
462 	if (tb[TCA_ROUTE4_CLASSID]) {
463 		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
464 		tcf_bind_filter(tp, &f->res, base);
465 	}
466 
467 	tcf_exts_change(tp, &f->exts, &e);
468 
469 	return 0;
470 errout:
471 	tcf_exts_destroy(&e);
472 	return err;
473 }
474 
475 static int route4_change(struct net *net, struct sk_buff *in_skb,
476 			 struct tcf_proto *tp, unsigned long base, u32 handle,
477 			 struct nlattr **tca, unsigned long *arg, bool ovr)
478 {
479 	struct route4_head *head = rtnl_dereference(tp->root);
480 	struct route4_filter __rcu **fp;
481 	struct route4_filter *fold, *f1, *pfp, *f = NULL;
482 	struct route4_bucket *b;
483 	struct nlattr *opt = tca[TCA_OPTIONS];
484 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
485 	unsigned int h, th;
486 	int err;
487 	bool new = true;
488 
489 	if (opt == NULL)
490 		return handle ? -EINVAL : 0;
491 
492 	err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy);
493 	if (err < 0)
494 		return err;
495 
496 	fold = (struct route4_filter *)*arg;
497 	if (fold && handle && fold->handle != handle)
498 			return -EINVAL;
499 
500 	err = -ENOBUFS;
501 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
502 	if (!f)
503 		goto errout;
504 
505 	err = tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
506 	if (err < 0)
507 		goto errout;
508 
509 	if (fold) {
510 		f->id = fold->id;
511 		f->iif = fold->iif;
512 		f->res = fold->res;
513 		f->handle = fold->handle;
514 
515 		f->tp = fold->tp;
516 		f->bkt = fold->bkt;
517 		new = false;
518 	}
519 
520 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
521 			       tca[TCA_RATE], new, ovr);
522 	if (err < 0)
523 		goto errout;
524 
525 	h = from_hash(f->handle >> 16);
526 	fp = &f->bkt->ht[h];
527 	for (pfp = rtnl_dereference(*fp);
528 	     (f1 = rtnl_dereference(*fp)) != NULL;
529 	     fp = &f1->next)
530 		if (f->handle < f1->handle)
531 			break;
532 
533 	netif_keep_dst(qdisc_dev(tp->q));
534 	rcu_assign_pointer(f->next, f1);
535 	rcu_assign_pointer(*fp, f);
536 
537 	if (fold && fold->handle && f->handle != fold->handle) {
538 		th = to_hash(fold->handle);
539 		h = from_hash(fold->handle >> 16);
540 		b = rtnl_dereference(head->table[th]);
541 		if (b) {
542 			fp = &b->ht[h];
543 			for (pfp = rtnl_dereference(*fp); pfp;
544 			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
545 				if (pfp == f) {
546 					*fp = f->next;
547 					break;
548 				}
549 			}
550 		}
551 	}
552 
553 	route4_reset_fastmap(head);
554 	*arg = (unsigned long)f;
555 	if (fold) {
556 		tcf_unbind_filter(tp, &fold->res);
557 		call_rcu(&fold->rcu, route4_delete_filter);
558 	}
559 	return 0;
560 
561 errout:
562 	if (f)
563 		tcf_exts_destroy(&f->exts);
564 	kfree(f);
565 	return err;
566 }
567 
568 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
569 {
570 	struct route4_head *head = rtnl_dereference(tp->root);
571 	unsigned int h, h1;
572 
573 	if (head == NULL)
574 		arg->stop = 1;
575 
576 	if (arg->stop)
577 		return;
578 
579 	for (h = 0; h <= 256; h++) {
580 		struct route4_bucket *b = rtnl_dereference(head->table[h]);
581 
582 		if (b) {
583 			for (h1 = 0; h1 <= 32; h1++) {
584 				struct route4_filter *f;
585 
586 				for (f = rtnl_dereference(b->ht[h1]);
587 				     f;
588 				     f = rtnl_dereference(f->next)) {
589 					if (arg->count < arg->skip) {
590 						arg->count++;
591 						continue;
592 					}
593 					if (arg->fn(tp, (unsigned long)f, arg) < 0) {
594 						arg->stop = 1;
595 						return;
596 					}
597 					arg->count++;
598 				}
599 			}
600 		}
601 	}
602 }
603 
604 static int route4_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
605 		       struct sk_buff *skb, struct tcmsg *t)
606 {
607 	struct route4_filter *f = (struct route4_filter *)fh;
608 	struct nlattr *nest;
609 	u32 id;
610 
611 	if (f == NULL)
612 		return skb->len;
613 
614 	t->tcm_handle = f->handle;
615 
616 	nest = nla_nest_start(skb, TCA_OPTIONS);
617 	if (nest == NULL)
618 		goto nla_put_failure;
619 
620 	if (!(f->handle & 0x8000)) {
621 		id = f->id & 0xFF;
622 		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
623 			goto nla_put_failure;
624 	}
625 	if (f->handle & 0x80000000) {
626 		if ((f->handle >> 16) != 0xFFFF &&
627 		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
628 			goto nla_put_failure;
629 	} else {
630 		id = f->id >> 16;
631 		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
632 			goto nla_put_failure;
633 	}
634 	if (f->res.classid &&
635 	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
636 		goto nla_put_failure;
637 
638 	if (tcf_exts_dump(skb, &f->exts) < 0)
639 		goto nla_put_failure;
640 
641 	nla_nest_end(skb, nest);
642 
643 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
644 		goto nla_put_failure;
645 
646 	return skb->len;
647 
648 nla_put_failure:
649 	nla_nest_cancel(skb, nest);
650 	return -1;
651 }
652 
653 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
654 	.kind		=	"route",
655 	.classify	=	route4_classify,
656 	.init		=	route4_init,
657 	.destroy	=	route4_destroy,
658 	.get		=	route4_get,
659 	.change		=	route4_change,
660 	.delete		=	route4_delete,
661 	.walk		=	route4_walk,
662 	.dump		=	route4_dump,
663 	.owner		=	THIS_MODULE,
664 };
665 
666 static int __init init_route4(void)
667 {
668 	return register_tcf_proto_ops(&cls_route4_ops);
669 }
670 
671 static void __exit exit_route4(void)
672 {
673 	unregister_tcf_proto_ops(&cls_route4_ops);
674 }
675 
676 module_init(init_route4)
677 module_exit(exit_route4)
678 MODULE_LICENSE("GPL");
679