xref: /linux/net/sched/cls_route.c (revision cc04a46f11ea046ed53e2c832ae29e4790f7e35f) 
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
272 route4_delete_filter(struct rcu_head *head)
273 {
274 	struct route4_filter *f = container_of(head, struct route4_filter, rcu);
275 
276 	tcf_exts_destroy(&f->exts);
277 	kfree(f);
278 }
279 
280 static bool route4_destroy(struct tcf_proto *tp, bool force)
281 {
282 	struct route4_head *head = rtnl_dereference(tp->root);
283 	int h1, h2;
284 
285 	if (head == NULL)
286 		return true;
287 
288 	if (!force) {
289 		for (h1 = 0; h1 <= 256; h1++) {
290 			if (rcu_access_pointer(head->table[h1]))
291 				return false;
292 		}
293 	}
294 
295 	for (h1 = 0; h1 <= 256; h1++) {
296 		struct route4_bucket *b;
297 
298 		b = rtnl_dereference(head->table[h1]);
299 		if (b) {
300 			for (h2 = 0; h2 <= 32; h2++) {
301 				struct route4_filter *f;
302 
303 				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
304 					struct route4_filter *next;
305 
306 					next = rtnl_dereference(f->next);
307 					RCU_INIT_POINTER(b->ht[h2], next);
308 					tcf_unbind_filter(tp, &f->res);
309 					call_rcu(&f->rcu, route4_delete_filter);
310 				}
311 			}
312 			RCU_INIT_POINTER(head->table[h1], NULL);
313 			kfree_rcu(b, rcu);
314 		}
315 	}
316 	RCU_INIT_POINTER(tp->root, NULL);
317 	kfree_rcu(head, rcu);
318 	return true;
319 }
320 
321 static int route4_delete(struct tcf_proto *tp, unsigned long arg)
322 {
323 	struct route4_head *head = rtnl_dereference(tp->root);
324 	struct route4_filter *f = (struct route4_filter *)arg;
325 	struct route4_filter __rcu **fp;
326 	struct route4_filter *nf;
327 	struct route4_bucket *b;
328 	unsigned int h = 0;
329 	int i;
330 
331 	if (!head || !f)
332 		return -EINVAL;
333 
334 	h = f->handle;
335 	b = f->bkt;
336 
337 	fp = &b->ht[from_hash(h >> 16)];
338 	for (nf = rtnl_dereference(*fp); nf;
339 	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
340 		if (nf == f) {
341 			/* unlink it */
342 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
343 
344 			/* Remove any fastmap lookups that might ref filter
345 			 * notice we unlink'd the filter so we can't get it
346 			 * back in the fastmap.
347 			 */
348 			route4_reset_fastmap(head);
349 
350 			/* Delete it */
351 			tcf_unbind_filter(tp, &f->res);
352 			call_rcu(&f->rcu, route4_delete_filter);
353 
354 			/* Strip RTNL protected tree */
355 			for (i = 0; i <= 32; i++) {
356 				struct route4_filter *rt;
357 
358 				rt = rtnl_dereference(b->ht[i]);
359 				if (rt)
360 					return 0;
361 			}
362 
363 			/* OK, session has no flows */
364 			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
365 			kfree_rcu(b, rcu);
366 
367 			return 0;
368 		}
369 	}
370 	return 0;
371 }
372 
373 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
374 	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
375 	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
376 	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
377 	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
378 };
379 
380 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
381 			    unsigned long base, struct route4_filter *f,
382 			    u32 handle, struct route4_head *head,
383 			    struct nlattr **tb, struct nlattr *est, int new,
384 			    bool ovr)
385 {
386 	int err;
387 	u32 id = 0, to = 0, nhandle = 0x8000;
388 	struct route4_filter *fp;
389 	unsigned int h1;
390 	struct route4_bucket *b;
391 	struct tcf_exts e;
392 
393 	tcf_exts_init(&e, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
394 	err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
395 	if (err < 0)
396 		return err;
397 
398 	err = -EINVAL;
399 	if (tb[TCA_ROUTE4_TO]) {
400 		if (new && handle & 0x8000)
401 			goto errout;
402 		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
403 		if (to > 0xFF)
404 			goto errout;
405 		nhandle = to;
406 	}
407 
408 	if (tb[TCA_ROUTE4_FROM]) {
409 		if (tb[TCA_ROUTE4_IIF])
410 			goto errout;
411 		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
412 		if (id > 0xFF)
413 			goto errout;
414 		nhandle |= id << 16;
415 	} else if (tb[TCA_ROUTE4_IIF]) {
416 		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
417 		if (id > 0x7FFF)
418 			goto errout;
419 		nhandle |= (id | 0x8000) << 16;
420 	} else
421 		nhandle |= 0xFFFF << 16;
422 
423 	if (handle && new) {
424 		nhandle |= handle & 0x7F00;
425 		if (nhandle != handle)
426 			goto errout;
427 	}
428 
429 	h1 = to_hash(nhandle);
430 	b = rtnl_dereference(head->table[h1]);
431 	if (!b) {
432 		err = -ENOBUFS;
433 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
434 		if (b == NULL)
435 			goto errout;
436 
437 		rcu_assign_pointer(head->table[h1], b);
438 	} else {
439 		unsigned int h2 = from_hash(nhandle >> 16);
440 
441 		err = -EEXIST;
442 		for (fp = rtnl_dereference(b->ht[h2]);
443 		     fp;
444 		     fp = rtnl_dereference(fp->next))
445 			if (fp->handle == f->handle)
446 				goto errout;
447 	}
448 
449 	if (tb[TCA_ROUTE4_TO])
450 		f->id = to;
451 
452 	if (tb[TCA_ROUTE4_FROM])
453 		f->id = to | id<<16;
454 	else if (tb[TCA_ROUTE4_IIF])
455 		f->iif = id;
456 
457 	f->handle = nhandle;
458 	f->bkt = b;
459 	f->tp = tp;
460 
461 	if (tb[TCA_ROUTE4_CLASSID]) {
462 		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
463 		tcf_bind_filter(tp, &f->res, base);
464 	}
465 
466 	tcf_exts_change(tp, &f->exts, &e);
467 
468 	return 0;
469 errout:
470 	tcf_exts_destroy(&e);
471 	return err;
472 }
473 
474 static int route4_change(struct net *net, struct sk_buff *in_skb,
475 		       struct tcf_proto *tp, unsigned long base,
476 		       u32 handle,
477 		       struct nlattr **tca,
478 		       unsigned long *arg, bool ovr)
479 {
480 	struct route4_head *head = rtnl_dereference(tp->root);
481 	struct route4_filter __rcu **fp;
482 	struct route4_filter *fold, *f1, *pfp, *f = NULL;
483 	struct route4_bucket *b;
484 	struct nlattr *opt = tca[TCA_OPTIONS];
485 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
486 	unsigned int h, th;
487 	int err;
488 	bool new = true;
489 
490 	if (opt == NULL)
491 		return handle ? -EINVAL : 0;
492 
493 	err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy);
494 	if (err < 0)
495 		return err;
496 
497 	fold = (struct route4_filter *)*arg;
498 	if (fold && handle && fold->handle != handle)
499 			return -EINVAL;
500 
501 	err = -ENOBUFS;
502 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
503 	if (!f)
504 		goto errout;
505 
506 	tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
507 	if (fold) {
508 		f->id = fold->id;
509 		f->iif = fold->iif;
510 		f->res = fold->res;
511 		f->handle = fold->handle;
512 
513 		f->tp = fold->tp;
514 		f->bkt = fold->bkt;
515 		new = false;
516 	}
517 
518 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
519 			       tca[TCA_RATE], new, ovr);
520 	if (err < 0)
521 		goto errout;
522 
523 	h = from_hash(f->handle >> 16);
524 	fp = &f->bkt->ht[h];
525 	for (pfp = rtnl_dereference(*fp);
526 	     (f1 = rtnl_dereference(*fp)) != NULL;
527 	     fp = &f1->next)
528 		if (f->handle < f1->handle)
529 			break;
530 
531 	netif_keep_dst(qdisc_dev(tp->q));
532 	rcu_assign_pointer(f->next, f1);
533 	rcu_assign_pointer(*fp, f);
534 
535 	if (fold && fold->handle && f->handle != fold->handle) {
536 		th = to_hash(fold->handle);
537 		h = from_hash(fold->handle >> 16);
538 		b = rtnl_dereference(head->table[th]);
539 		if (b) {
540 			fp = &b->ht[h];
541 			for (pfp = rtnl_dereference(*fp); pfp;
542 			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
543 				if (pfp == f) {
544 					*fp = f->next;
545 					break;
546 				}
547 			}
548 		}
549 	}
550 
551 	route4_reset_fastmap(head);
552 	*arg = (unsigned long)f;
553 	if (fold) {
554 		tcf_unbind_filter(tp, &fold->res);
555 		call_rcu(&fold->rcu, route4_delete_filter);
556 	}
557 	return 0;
558 
559 errout:
560 	kfree(f);
561 	return err;
562 }
563 
564 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
565 {
566 	struct route4_head *head = rtnl_dereference(tp->root);
567 	unsigned int h, h1;
568 
569 	if (head == NULL)
570 		arg->stop = 1;
571 
572 	if (arg->stop)
573 		return;
574 
575 	for (h = 0; h <= 256; h++) {
576 		struct route4_bucket *b = rtnl_dereference(head->table[h]);
577 
578 		if (b) {
579 			for (h1 = 0; h1 <= 32; h1++) {
580 				struct route4_filter *f;
581 
582 				for (f = rtnl_dereference(b->ht[h1]);
583 				     f;
584 				     f = rtnl_dereference(f->next)) {
585 					if (arg->count < arg->skip) {
586 						arg->count++;
587 						continue;
588 					}
589 					if (arg->fn(tp, (unsigned long)f, arg) < 0) {
590 						arg->stop = 1;
591 						return;
592 					}
593 					arg->count++;
594 				}
595 			}
596 		}
597 	}
598 }
599 
600 static int route4_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
601 		       struct sk_buff *skb, struct tcmsg *t)
602 {
603 	struct route4_filter *f = (struct route4_filter *)fh;
604 	struct nlattr *nest;
605 	u32 id;
606 
607 	if (f == NULL)
608 		return skb->len;
609 
610 	t->tcm_handle = f->handle;
611 
612 	nest = nla_nest_start(skb, TCA_OPTIONS);
613 	if (nest == NULL)
614 		goto nla_put_failure;
615 
616 	if (!(f->handle & 0x8000)) {
617 		id = f->id & 0xFF;
618 		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
619 			goto nla_put_failure;
620 	}
621 	if (f->handle & 0x80000000) {
622 		if ((f->handle >> 16) != 0xFFFF &&
623 		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
624 			goto nla_put_failure;
625 	} else {
626 		id = f->id >> 16;
627 		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
628 			goto nla_put_failure;
629 	}
630 	if (f->res.classid &&
631 	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
632 		goto nla_put_failure;
633 
634 	if (tcf_exts_dump(skb, &f->exts) < 0)
635 		goto nla_put_failure;
636 
637 	nla_nest_end(skb, nest);
638 
639 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
640 		goto nla_put_failure;
641 
642 	return skb->len;
643 
644 nla_put_failure:
645 	nla_nest_cancel(skb, nest);
646 	return -1;
647 }
648 
649 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
650 	.kind		=	"route",
651 	.classify	=	route4_classify,
652 	.init		=	route4_init,
653 	.destroy	=	route4_destroy,
654 	.get		=	route4_get,
655 	.change		=	route4_change,
656 	.delete		=	route4_delete,
657 	.walk		=	route4_walk,
658 	.dump		=	route4_dump,
659 	.owner		=	THIS_MODULE,
660 };
661 
662 static int __init init_route4(void)
663 {
664 	return register_tcf_proto_ops(&cls_route4_ops);
665 }
666 
667 static void __exit exit_route4(void)
668 {
669 	unregister_tcf_proto_ops(&cls_route4_ops);
670 }
671 
672 module_init(init_route4)
673 module_exit(exit_route4)
674 MODULE_LICENSE("GPL");
675