xref: /linux/net/sched/cls_route.c (revision b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3) 
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 	union {
61 		struct work_struct	work;
62 		struct rcu_head		rcu;
63 	};
64 };
65 
66 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
67 
68 static inline int route4_fastmap_hash(u32 id, int iif)
69 {
70 	return id & 0xF;
71 }
72 
73 static DEFINE_SPINLOCK(fastmap_lock);
74 static void
75 route4_reset_fastmap(struct route4_head *head)
76 {
77 	spin_lock_bh(&fastmap_lock);
78 	memset(head->fastmap, 0, sizeof(head->fastmap));
79 	spin_unlock_bh(&fastmap_lock);
80 }
81 
82 static void
83 route4_set_fastmap(struct route4_head *head, u32 id, int iif,
84 		   struct route4_filter *f)
85 {
86 	int h = route4_fastmap_hash(id, iif);
87 
88 	/* fastmap updates must look atomic to aling id, iff, filter */
89 	spin_lock_bh(&fastmap_lock);
90 	head->fastmap[h].id = id;
91 	head->fastmap[h].iif = iif;
92 	head->fastmap[h].filter = f;
93 	spin_unlock_bh(&fastmap_lock);
94 }
95 
96 static inline int route4_hash_to(u32 id)
97 {
98 	return id & 0xFF;
99 }
100 
101 static inline int route4_hash_from(u32 id)
102 {
103 	return (id >> 16) & 0xF;
104 }
105 
106 static inline int route4_hash_iif(int iif)
107 {
108 	return 16 + ((iif >> 16) & 0xF);
109 }
110 
111 static inline int route4_hash_wild(void)
112 {
113 	return 32;
114 }
115 
116 #define ROUTE4_APPLY_RESULT()					\
117 {								\
118 	*res = f->res;						\
119 	if (tcf_exts_has_actions(&f->exts)) {			\
120 		int r = tcf_exts_exec(skb, &f->exts, res);	\
121 		if (r < 0) {					\
122 			dont_cache = 1;				\
123 			continue;				\
124 		}						\
125 		return r;					\
126 	} else if (!dont_cache)					\
127 		route4_set_fastmap(head, id, iif, f);		\
128 	return 0;						\
129 }
130 
131 static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
132 			   struct tcf_result *res)
133 {
134 	struct route4_head *head = rcu_dereference_bh(tp->root);
135 	struct dst_entry *dst;
136 	struct route4_bucket *b;
137 	struct route4_filter *f;
138 	u32 id, h;
139 	int iif, dont_cache = 0;
140 
141 	dst = skb_dst(skb);
142 	if (!dst)
143 		goto failure;
144 
145 	id = dst->tclassid;
146 
147 	iif = inet_iif(skb);
148 
149 	h = route4_fastmap_hash(id, iif);
150 
151 	spin_lock(&fastmap_lock);
152 	if (id == head->fastmap[h].id &&
153 	    iif == head->fastmap[h].iif &&
154 	    (f = head->fastmap[h].filter) != NULL) {
155 		if (f == ROUTE4_FAILURE) {
156 			spin_unlock(&fastmap_lock);
157 			goto failure;
158 		}
159 
160 		*res = f->res;
161 		spin_unlock(&fastmap_lock);
162 		return 0;
163 	}
164 	spin_unlock(&fastmap_lock);
165 
166 	h = route4_hash_to(id);
167 
168 restart:
169 	b = rcu_dereference_bh(head->table[h]);
170 	if (b) {
171 		for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
172 		     f;
173 		     f = rcu_dereference_bh(f->next))
174 			if (f->id == id)
175 				ROUTE4_APPLY_RESULT();
176 
177 		for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
178 		     f;
179 		     f = rcu_dereference_bh(f->next))
180 			if (f->iif == iif)
181 				ROUTE4_APPLY_RESULT();
182 
183 		for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
184 		     f;
185 		     f = rcu_dereference_bh(f->next))
186 			ROUTE4_APPLY_RESULT();
187 	}
188 	if (h < 256) {
189 		h = 256;
190 		id &= ~0xFFFF;
191 		goto restart;
192 	}
193 
194 	if (!dont_cache)
195 		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
196 failure:
197 	return -1;
198 }
199 
200 static inline u32 to_hash(u32 id)
201 {
202 	u32 h = id & 0xFF;
203 
204 	if (id & 0x8000)
205 		h += 256;
206 	return h;
207 }
208 
209 static inline u32 from_hash(u32 id)
210 {
211 	id &= 0xFFFF;
212 	if (id == 0xFFFF)
213 		return 32;
214 	if (!(id & 0x8000)) {
215 		if (id > 255)
216 			return 256;
217 		return id & 0xF;
218 	}
219 	return 16 + (id & 0xF);
220 }
221 
222 static void *route4_get(struct tcf_proto *tp, u32 handle)
223 {
224 	struct route4_head *head = rtnl_dereference(tp->root);
225 	struct route4_bucket *b;
226 	struct route4_filter *f;
227 	unsigned int h1, h2;
228 
229 	h1 = to_hash(handle);
230 	if (h1 > 256)
231 		return NULL;
232 
233 	h2 = from_hash(handle >> 16);
234 	if (h2 > 32)
235 		return NULL;
236 
237 	b = rtnl_dereference(head->table[h1]);
238 	if (b) {
239 		for (f = rtnl_dereference(b->ht[h2]);
240 		     f;
241 		     f = rtnl_dereference(f->next))
242 			if (f->handle == handle)
243 				return f;
244 	}
245 	return NULL;
246 }
247 
248 static int route4_init(struct tcf_proto *tp)
249 {
250 	struct route4_head *head;
251 
252 	head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
253 	if (head == NULL)
254 		return -ENOBUFS;
255 
256 	rcu_assign_pointer(tp->root, head);
257 	return 0;
258 }
259 
260 static void route4_delete_filter_work(struct work_struct *work)
261 {
262 	struct route4_filter *f = container_of(work, struct route4_filter, work);
263 
264 	rtnl_lock();
265 	tcf_exts_destroy(&f->exts);
266 	kfree(f);
267 	rtnl_unlock();
268 }
269 
270 static void route4_delete_filter(struct rcu_head *head)
271 {
272 	struct route4_filter *f = container_of(head, struct route4_filter, rcu);
273 
274 	INIT_WORK(&f->work, route4_delete_filter_work);
275 	tcf_queue_work(&f->work);
276 }
277 
278 static void route4_destroy(struct tcf_proto *tp)
279 {
280 	struct route4_head *head = rtnl_dereference(tp->root);
281 	int h1, h2;
282 
283 	if (head == NULL)
284 		return;
285 
286 	for (h1 = 0; h1 <= 256; h1++) {
287 		struct route4_bucket *b;
288 
289 		b = rtnl_dereference(head->table[h1]);
290 		if (b) {
291 			for (h2 = 0; h2 <= 32; h2++) {
292 				struct route4_filter *f;
293 
294 				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
295 					struct route4_filter *next;
296 
297 					next = rtnl_dereference(f->next);
298 					RCU_INIT_POINTER(b->ht[h2], next);
299 					tcf_unbind_filter(tp, &f->res);
300 					call_rcu(&f->rcu, route4_delete_filter);
301 				}
302 			}
303 			RCU_INIT_POINTER(head->table[h1], NULL);
304 			kfree_rcu(b, rcu);
305 		}
306 	}
307 	kfree_rcu(head, rcu);
308 }
309 
310 static int route4_delete(struct tcf_proto *tp, void *arg, bool *last)
311 {
312 	struct route4_head *head = rtnl_dereference(tp->root);
313 	struct route4_filter *f = arg;
314 	struct route4_filter __rcu **fp;
315 	struct route4_filter *nf;
316 	struct route4_bucket *b;
317 	unsigned int h = 0;
318 	int i, h1;
319 
320 	if (!head || !f)
321 		return -EINVAL;
322 
323 	h = f->handle;
324 	b = f->bkt;
325 
326 	fp = &b->ht[from_hash(h >> 16)];
327 	for (nf = rtnl_dereference(*fp); nf;
328 	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
329 		if (nf == f) {
330 			/* unlink it */
331 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
332 
333 			/* Remove any fastmap lookups that might ref filter
334 			 * notice we unlink'd the filter so we can't get it
335 			 * back in the fastmap.
336 			 */
337 			route4_reset_fastmap(head);
338 
339 			/* Delete it */
340 			tcf_unbind_filter(tp, &f->res);
341 			call_rcu(&f->rcu, route4_delete_filter);
342 
343 			/* Strip RTNL protected tree */
344 			for (i = 0; i <= 32; i++) {
345 				struct route4_filter *rt;
346 
347 				rt = rtnl_dereference(b->ht[i]);
348 				if (rt)
349 					goto out;
350 			}
351 
352 			/* OK, session has no flows */
353 			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
354 			kfree_rcu(b, rcu);
355 			break;
356 		}
357 	}
358 
359 out:
360 	*last = true;
361 	for (h1 = 0; h1 <= 256; h1++) {
362 		if (rcu_access_pointer(head->table[h1])) {
363 			*last = false;
364 			break;
365 		}
366 	}
367 
368 	return 0;
369 }
370 
371 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
372 	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
373 	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
374 	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
375 	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
376 };
377 
378 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
379 			    unsigned long base, struct route4_filter *f,
380 			    u32 handle, struct route4_head *head,
381 			    struct nlattr **tb, struct nlattr *est, int new,
382 			    bool ovr)
383 {
384 	u32 id = 0, to = 0, nhandle = 0x8000;
385 	struct route4_filter *fp;
386 	unsigned int h1;
387 	struct route4_bucket *b;
388 	int err;
389 
390 	err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr);
391 	if (err < 0)
392 		return err;
393 
394 	if (tb[TCA_ROUTE4_TO]) {
395 		if (new && handle & 0x8000)
396 			return -EINVAL;
397 		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
398 		if (to > 0xFF)
399 			return -EINVAL;
400 		nhandle = to;
401 	}
402 
403 	if (tb[TCA_ROUTE4_FROM]) {
404 		if (tb[TCA_ROUTE4_IIF])
405 			return -EINVAL;
406 		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
407 		if (id > 0xFF)
408 			return -EINVAL;
409 		nhandle |= id << 16;
410 	} else if (tb[TCA_ROUTE4_IIF]) {
411 		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
412 		if (id > 0x7FFF)
413 			return -EINVAL;
414 		nhandle |= (id | 0x8000) << 16;
415 	} else
416 		nhandle |= 0xFFFF << 16;
417 
418 	if (handle && new) {
419 		nhandle |= handle & 0x7F00;
420 		if (nhandle != handle)
421 			return -EINVAL;
422 	}
423 
424 	h1 = to_hash(nhandle);
425 	b = rtnl_dereference(head->table[h1]);
426 	if (!b) {
427 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
428 		if (b == NULL)
429 			return -ENOBUFS;
430 
431 		rcu_assign_pointer(head->table[h1], b);
432 	} else {
433 		unsigned int h2 = from_hash(nhandle >> 16);
434 
435 		for (fp = rtnl_dereference(b->ht[h2]);
436 		     fp;
437 		     fp = rtnl_dereference(fp->next))
438 			if (fp->handle == f->handle)
439 				return -EEXIST;
440 	}
441 
442 	if (tb[TCA_ROUTE4_TO])
443 		f->id = to;
444 
445 	if (tb[TCA_ROUTE4_FROM])
446 		f->id = to | id<<16;
447 	else if (tb[TCA_ROUTE4_IIF])
448 		f->iif = id;
449 
450 	f->handle = nhandle;
451 	f->bkt = b;
452 	f->tp = tp;
453 
454 	if (tb[TCA_ROUTE4_CLASSID]) {
455 		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
456 		tcf_bind_filter(tp, &f->res, base);
457 	}
458 
459 	return 0;
460 }
461 
462 static int route4_change(struct net *net, struct sk_buff *in_skb,
463 			 struct tcf_proto *tp, unsigned long base, u32 handle,
464 			 struct nlattr **tca, void **arg, bool ovr)
465 {
466 	struct route4_head *head = rtnl_dereference(tp->root);
467 	struct route4_filter __rcu **fp;
468 	struct route4_filter *fold, *f1, *pfp, *f = NULL;
469 	struct route4_bucket *b;
470 	struct nlattr *opt = tca[TCA_OPTIONS];
471 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
472 	unsigned int h, th;
473 	int err;
474 	bool new = true;
475 
476 	if (opt == NULL)
477 		return handle ? -EINVAL : 0;
478 
479 	err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy, NULL);
480 	if (err < 0)
481 		return err;
482 
483 	fold = *arg;
484 	if (fold && handle && fold->handle != handle)
485 			return -EINVAL;
486 
487 	err = -ENOBUFS;
488 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
489 	if (!f)
490 		goto errout;
491 
492 	err = tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
493 	if (err < 0)
494 		goto errout;
495 
496 	if (fold) {
497 		f->id = fold->id;
498 		f->iif = fold->iif;
499 		f->res = fold->res;
500 		f->handle = fold->handle;
501 
502 		f->tp = fold->tp;
503 		f->bkt = fold->bkt;
504 		new = false;
505 	}
506 
507 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
508 			       tca[TCA_RATE], new, ovr);
509 	if (err < 0)
510 		goto errout;
511 
512 	h = from_hash(f->handle >> 16);
513 	fp = &f->bkt->ht[h];
514 	for (pfp = rtnl_dereference(*fp);
515 	     (f1 = rtnl_dereference(*fp)) != NULL;
516 	     fp = &f1->next)
517 		if (f->handle < f1->handle)
518 			break;
519 
520 	netif_keep_dst(qdisc_dev(tp->q));
521 	rcu_assign_pointer(f->next, f1);
522 	rcu_assign_pointer(*fp, f);
523 
524 	if (fold && fold->handle && f->handle != fold->handle) {
525 		th = to_hash(fold->handle);
526 		h = from_hash(fold->handle >> 16);
527 		b = rtnl_dereference(head->table[th]);
528 		if (b) {
529 			fp = &b->ht[h];
530 			for (pfp = rtnl_dereference(*fp); pfp;
531 			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
532 				if (pfp == f) {
533 					*fp = f->next;
534 					break;
535 				}
536 			}
537 		}
538 	}
539 
540 	route4_reset_fastmap(head);
541 	*arg = f;
542 	if (fold) {
543 		tcf_unbind_filter(tp, &fold->res);
544 		call_rcu(&fold->rcu, route4_delete_filter);
545 	}
546 	return 0;
547 
548 errout:
549 	if (f)
550 		tcf_exts_destroy(&f->exts);
551 	kfree(f);
552 	return err;
553 }
554 
555 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
556 {
557 	struct route4_head *head = rtnl_dereference(tp->root);
558 	unsigned int h, h1;
559 
560 	if (head == NULL)
561 		arg->stop = 1;
562 
563 	if (arg->stop)
564 		return;
565 
566 	for (h = 0; h <= 256; h++) {
567 		struct route4_bucket *b = rtnl_dereference(head->table[h]);
568 
569 		if (b) {
570 			for (h1 = 0; h1 <= 32; h1++) {
571 				struct route4_filter *f;
572 
573 				for (f = rtnl_dereference(b->ht[h1]);
574 				     f;
575 				     f = rtnl_dereference(f->next)) {
576 					if (arg->count < arg->skip) {
577 						arg->count++;
578 						continue;
579 					}
580 					if (arg->fn(tp, f, arg) < 0) {
581 						arg->stop = 1;
582 						return;
583 					}
584 					arg->count++;
585 				}
586 			}
587 		}
588 	}
589 }
590 
591 static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
592 		       struct sk_buff *skb, struct tcmsg *t)
593 {
594 	struct route4_filter *f = fh;
595 	struct nlattr *nest;
596 	u32 id;
597 
598 	if (f == NULL)
599 		return skb->len;
600 
601 	t->tcm_handle = f->handle;
602 
603 	nest = nla_nest_start(skb, TCA_OPTIONS);
604 	if (nest == NULL)
605 		goto nla_put_failure;
606 
607 	if (!(f->handle & 0x8000)) {
608 		id = f->id & 0xFF;
609 		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
610 			goto nla_put_failure;
611 	}
612 	if (f->handle & 0x80000000) {
613 		if ((f->handle >> 16) != 0xFFFF &&
614 		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
615 			goto nla_put_failure;
616 	} else {
617 		id = f->id >> 16;
618 		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
619 			goto nla_put_failure;
620 	}
621 	if (f->res.classid &&
622 	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
623 		goto nla_put_failure;
624 
625 	if (tcf_exts_dump(skb, &f->exts) < 0)
626 		goto nla_put_failure;
627 
628 	nla_nest_end(skb, nest);
629 
630 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
631 		goto nla_put_failure;
632 
633 	return skb->len;
634 
635 nla_put_failure:
636 	nla_nest_cancel(skb, nest);
637 	return -1;
638 }
639 
640 static void route4_bind_class(void *fh, u32 classid, unsigned long cl)
641 {
642 	struct route4_filter *f = fh;
643 
644 	if (f && f->res.classid == classid)
645 		f->res.class = cl;
646 }
647 
648 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
649 	.kind		=	"route",
650 	.classify	=	route4_classify,
651 	.init		=	route4_init,
652 	.destroy	=	route4_destroy,
653 	.get		=	route4_get,
654 	.change		=	route4_change,
655 	.delete		=	route4_delete,
656 	.walk		=	route4_walk,
657 	.dump		=	route4_dump,
658 	.bind_class	=	route4_bind_class,
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