xref: /linux/net/sched/cls_route.c (revision 9a8f32038a74cb800e9649afbf4b3dba2b7d6539) 
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_work		rwork;
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_has_actions(&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 
144 	iif = inet_iif(skb);
145 
146 	h = route4_fastmap_hash(id, iif);
147 
148 	spin_lock(&fastmap_lock);
149 	if (id == head->fastmap[h].id &&
150 	    iif == head->fastmap[h].iif &&
151 	    (f = head->fastmap[h].filter) != NULL) {
152 		if (f == ROUTE4_FAILURE) {
153 			spin_unlock(&fastmap_lock);
154 			goto failure;
155 		}
156 
157 		*res = f->res;
158 		spin_unlock(&fastmap_lock);
159 		return 0;
160 	}
161 	spin_unlock(&fastmap_lock);
162 
163 	h = route4_hash_to(id);
164 
165 restart:
166 	b = rcu_dereference_bh(head->table[h]);
167 	if (b) {
168 		for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
169 		     f;
170 		     f = rcu_dereference_bh(f->next))
171 			if (f->id == id)
172 				ROUTE4_APPLY_RESULT();
173 
174 		for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
175 		     f;
176 		     f = rcu_dereference_bh(f->next))
177 			if (f->iif == iif)
178 				ROUTE4_APPLY_RESULT();
179 
180 		for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
181 		     f;
182 		     f = rcu_dereference_bh(f->next))
183 			ROUTE4_APPLY_RESULT();
184 	}
185 	if (h < 256) {
186 		h = 256;
187 		id &= ~0xFFFF;
188 		goto restart;
189 	}
190 
191 	if (!dont_cache)
192 		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
193 failure:
194 	return -1;
195 }
196 
197 static inline u32 to_hash(u32 id)
198 {
199 	u32 h = id & 0xFF;
200 
201 	if (id & 0x8000)
202 		h += 256;
203 	return h;
204 }
205 
206 static inline u32 from_hash(u32 id)
207 {
208 	id &= 0xFFFF;
209 	if (id == 0xFFFF)
210 		return 32;
211 	if (!(id & 0x8000)) {
212 		if (id > 255)
213 			return 256;
214 		return id & 0xF;
215 	}
216 	return 16 + (id & 0xF);
217 }
218 
219 static void *route4_get(struct tcf_proto *tp, u32 handle)
220 {
221 	struct route4_head *head = rtnl_dereference(tp->root);
222 	struct route4_bucket *b;
223 	struct route4_filter *f;
224 	unsigned int h1, h2;
225 
226 	h1 = to_hash(handle);
227 	if (h1 > 256)
228 		return NULL;
229 
230 	h2 = from_hash(handle >> 16);
231 	if (h2 > 32)
232 		return NULL;
233 
234 	b = rtnl_dereference(head->table[h1]);
235 	if (b) {
236 		for (f = rtnl_dereference(b->ht[h2]);
237 		     f;
238 		     f = rtnl_dereference(f->next))
239 			if (f->handle == handle)
240 				return f;
241 	}
242 	return NULL;
243 }
244 
245 static int route4_init(struct tcf_proto *tp)
246 {
247 	struct route4_head *head;
248 
249 	head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
250 	if (head == NULL)
251 		return -ENOBUFS;
252 
253 	rcu_assign_pointer(tp->root, head);
254 	return 0;
255 }
256 
257 static void __route4_delete_filter(struct route4_filter *f)
258 {
259 	tcf_exts_destroy(&f->exts);
260 	tcf_exts_put_net(&f->exts);
261 	kfree(f);
262 }
263 
264 static void route4_delete_filter_work(struct work_struct *work)
265 {
266 	struct route4_filter *f = container_of(to_rcu_work(work),
267 					       struct route4_filter,
268 					       rwork);
269 	rtnl_lock();
270 	__route4_delete_filter(f);
271 	rtnl_unlock();
272 }
273 
274 static void route4_queue_work(struct route4_filter *f)
275 {
276 	tcf_queue_work(&f->rwork, route4_delete_filter_work);
277 }
278 
279 static void route4_destroy(struct tcf_proto *tp, bool rtnl_held,
280 			   struct netlink_ext_ack *extack)
281 {
282 	struct route4_head *head = rtnl_dereference(tp->root);
283 	int h1, h2;
284 
285 	if (head == NULL)
286 		return;
287 
288 	for (h1 = 0; h1 <= 256; h1++) {
289 		struct route4_bucket *b;
290 
291 		b = rtnl_dereference(head->table[h1]);
292 		if (b) {
293 			for (h2 = 0; h2 <= 32; h2++) {
294 				struct route4_filter *f;
295 
296 				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
297 					struct route4_filter *next;
298 
299 					next = rtnl_dereference(f->next);
300 					RCU_INIT_POINTER(b->ht[h2], next);
301 					tcf_unbind_filter(tp, &f->res);
302 					if (tcf_exts_get_net(&f->exts))
303 						route4_queue_work(f);
304 					else
305 						__route4_delete_filter(f);
306 				}
307 			}
308 			RCU_INIT_POINTER(head->table[h1], NULL);
309 			kfree_rcu(b, rcu);
310 		}
311 	}
312 	kfree_rcu(head, rcu);
313 }
314 
315 static int route4_delete(struct tcf_proto *tp, void *arg, bool *last,
316 			 bool rtnl_held, struct netlink_ext_ack *extack)
317 {
318 	struct route4_head *head = rtnl_dereference(tp->root);
319 	struct route4_filter *f = arg;
320 	struct route4_filter __rcu **fp;
321 	struct route4_filter *nf;
322 	struct route4_bucket *b;
323 	unsigned int h = 0;
324 	int i, h1;
325 
326 	if (!head || !f)
327 		return -EINVAL;
328 
329 	h = f->handle;
330 	b = f->bkt;
331 
332 	fp = &b->ht[from_hash(h >> 16)];
333 	for (nf = rtnl_dereference(*fp); nf;
334 	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
335 		if (nf == f) {
336 			/* unlink it */
337 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
338 
339 			/* Remove any fastmap lookups that might ref filter
340 			 * notice we unlink'd the filter so we can't get it
341 			 * back in the fastmap.
342 			 */
343 			route4_reset_fastmap(head);
344 
345 			/* Delete it */
346 			tcf_unbind_filter(tp, &f->res);
347 			tcf_exts_get_net(&f->exts);
348 			tcf_queue_work(&f->rwork, route4_delete_filter_work);
349 
350 			/* Strip RTNL protected tree */
351 			for (i = 0; i <= 32; i++) {
352 				struct route4_filter *rt;
353 
354 				rt = rtnl_dereference(b->ht[i]);
355 				if (rt)
356 					goto out;
357 			}
358 
359 			/* OK, session has no flows */
360 			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
361 			kfree_rcu(b, rcu);
362 			break;
363 		}
364 	}
365 
366 out:
367 	*last = true;
368 	for (h1 = 0; h1 <= 256; h1++) {
369 		if (rcu_access_pointer(head->table[h1])) {
370 			*last = false;
371 			break;
372 		}
373 	}
374 
375 	return 0;
376 }
377 
378 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
379 	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
380 	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
381 	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
382 	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
383 };
384 
385 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
386 			    unsigned long base, struct route4_filter *f,
387 			    u32 handle, struct route4_head *head,
388 			    struct nlattr **tb, struct nlattr *est, int new,
389 			    bool ovr, struct netlink_ext_ack *extack)
390 {
391 	u32 id = 0, to = 0, nhandle = 0x8000;
392 	struct route4_filter *fp;
393 	unsigned int h1;
394 	struct route4_bucket *b;
395 	int err;
396 
397 	err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, true, extack);
398 	if (err < 0)
399 		return err;
400 
401 	if (tb[TCA_ROUTE4_TO]) {
402 		if (new && handle & 0x8000)
403 			return -EINVAL;
404 		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
405 		if (to > 0xFF)
406 			return -EINVAL;
407 		nhandle = to;
408 	}
409 
410 	if (tb[TCA_ROUTE4_FROM]) {
411 		if (tb[TCA_ROUTE4_IIF])
412 			return -EINVAL;
413 		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
414 		if (id > 0xFF)
415 			return -EINVAL;
416 		nhandle |= id << 16;
417 	} else if (tb[TCA_ROUTE4_IIF]) {
418 		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
419 		if (id > 0x7FFF)
420 			return -EINVAL;
421 		nhandle |= (id | 0x8000) << 16;
422 	} else
423 		nhandle |= 0xFFFF << 16;
424 
425 	if (handle && new) {
426 		nhandle |= handle & 0x7F00;
427 		if (nhandle != handle)
428 			return -EINVAL;
429 	}
430 
431 	h1 = to_hash(nhandle);
432 	b = rtnl_dereference(head->table[h1]);
433 	if (!b) {
434 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
435 		if (b == NULL)
436 			return -ENOBUFS;
437 
438 		rcu_assign_pointer(head->table[h1], b);
439 	} else {
440 		unsigned int h2 = from_hash(nhandle >> 16);
441 
442 		for (fp = rtnl_dereference(b->ht[h2]);
443 		     fp;
444 		     fp = rtnl_dereference(fp->next))
445 			if (fp->handle == f->handle)
446 				return -EEXIST;
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 	return 0;
467 }
468 
469 static int route4_change(struct net *net, struct sk_buff *in_skb,
470 			 struct tcf_proto *tp, unsigned long base, u32 handle,
471 			 struct nlattr **tca, void **arg, bool ovr,
472 			 bool rtnl_held, struct netlink_ext_ack *extack)
473 {
474 	struct route4_head *head = rtnl_dereference(tp->root);
475 	struct route4_filter __rcu **fp;
476 	struct route4_filter *fold, *f1, *pfp, *f = NULL;
477 	struct route4_bucket *b;
478 	struct nlattr *opt = tca[TCA_OPTIONS];
479 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
480 	unsigned int h, th;
481 	int err;
482 	bool new = true;
483 
484 	if (opt == NULL)
485 		return handle ? -EINVAL : 0;
486 
487 	err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy, NULL);
488 	if (err < 0)
489 		return err;
490 
491 	fold = *arg;
492 	if (fold && handle && fold->handle != handle)
493 			return -EINVAL;
494 
495 	err = -ENOBUFS;
496 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
497 	if (!f)
498 		goto errout;
499 
500 	err = tcf_exts_init(&f->exts, net, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
501 	if (err < 0)
502 		goto errout;
503 
504 	if (fold) {
505 		f->id = fold->id;
506 		f->iif = fold->iif;
507 		f->res = fold->res;
508 		f->handle = fold->handle;
509 
510 		f->tp = fold->tp;
511 		f->bkt = fold->bkt;
512 		new = false;
513 	}
514 
515 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
516 			       tca[TCA_RATE], new, ovr, extack);
517 	if (err < 0)
518 		goto errout;
519 
520 	h = from_hash(f->handle >> 16);
521 	fp = &f->bkt->ht[h];
522 	for (pfp = rtnl_dereference(*fp);
523 	     (f1 = rtnl_dereference(*fp)) != NULL;
524 	     fp = &f1->next)
525 		if (f->handle < f1->handle)
526 			break;
527 
528 	tcf_block_netif_keep_dst(tp->chain->block);
529 	rcu_assign_pointer(f->next, f1);
530 	rcu_assign_pointer(*fp, f);
531 
532 	if (fold && fold->handle && f->handle != fold->handle) {
533 		th = to_hash(fold->handle);
534 		h = from_hash(fold->handle >> 16);
535 		b = rtnl_dereference(head->table[th]);
536 		if (b) {
537 			fp = &b->ht[h];
538 			for (pfp = rtnl_dereference(*fp); pfp;
539 			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
540 				if (pfp == f) {
541 					*fp = f->next;
542 					break;
543 				}
544 			}
545 		}
546 	}
547 
548 	route4_reset_fastmap(head);
549 	*arg = f;
550 	if (fold) {
551 		tcf_unbind_filter(tp, &fold->res);
552 		tcf_exts_get_net(&fold->exts);
553 		tcf_queue_work(&fold->rwork, route4_delete_filter_work);
554 	}
555 	return 0;
556 
557 errout:
558 	if (f)
559 		tcf_exts_destroy(&f->exts);
560 	kfree(f);
561 	return err;
562 }
563 
564 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
565 			bool rtnl_held)
566 {
567 	struct route4_head *head = rtnl_dereference(tp->root);
568 	unsigned int h, h1;
569 
570 	if (head == NULL || arg->stop)
571 		return;
572 
573 	for (h = 0; h <= 256; h++) {
574 		struct route4_bucket *b = rtnl_dereference(head->table[h]);
575 
576 		if (b) {
577 			for (h1 = 0; h1 <= 32; h1++) {
578 				struct route4_filter *f;
579 
580 				for (f = rtnl_dereference(b->ht[h1]);
581 				     f;
582 				     f = rtnl_dereference(f->next)) {
583 					if (arg->count < arg->skip) {
584 						arg->count++;
585 						continue;
586 					}
587 					if (arg->fn(tp, f, arg) < 0) {
588 						arg->stop = 1;
589 						return;
590 					}
591 					arg->count++;
592 				}
593 			}
594 		}
595 	}
596 }
597 
598 static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
599 		       struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
600 {
601 	struct route4_filter *f = fh;
602 	struct nlattr *nest;
603 	u32 id;
604 
605 	if (f == NULL)
606 		return skb->len;
607 
608 	t->tcm_handle = f->handle;
609 
610 	nest = nla_nest_start(skb, TCA_OPTIONS);
611 	if (nest == NULL)
612 		goto nla_put_failure;
613 
614 	if (!(f->handle & 0x8000)) {
615 		id = f->id & 0xFF;
616 		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
617 			goto nla_put_failure;
618 	}
619 	if (f->handle & 0x80000000) {
620 		if ((f->handle >> 16) != 0xFFFF &&
621 		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
622 			goto nla_put_failure;
623 	} else {
624 		id = f->id >> 16;
625 		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
626 			goto nla_put_failure;
627 	}
628 	if (f->res.classid &&
629 	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
630 		goto nla_put_failure;
631 
632 	if (tcf_exts_dump(skb, &f->exts) < 0)
633 		goto nla_put_failure;
634 
635 	nla_nest_end(skb, nest);
636 
637 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
638 		goto nla_put_failure;
639 
640 	return skb->len;
641 
642 nla_put_failure:
643 	nla_nest_cancel(skb, nest);
644 	return -1;
645 }
646 
647 static void route4_bind_class(void *fh, u32 classid, unsigned long cl)
648 {
649 	struct route4_filter *f = fh;
650 
651 	if (f && f->res.classid == classid)
652 		f->res.class = cl;
653 }
654 
655 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
656 	.kind		=	"route",
657 	.classify	=	route4_classify,
658 	.init		=	route4_init,
659 	.destroy	=	route4_destroy,
660 	.get		=	route4_get,
661 	.change		=	route4_change,
662 	.delete		=	route4_delete,
663 	.walk		=	route4_walk,
664 	.dump		=	route4_dump,
665 	.bind_class	=	route4_bind_class,
666 	.owner		=	THIS_MODULE,
667 };
668 
669 static int __init init_route4(void)
670 {
671 	return register_tcf_proto_ops(&cls_route4_ops);
672 }
673 
674 static void __exit exit_route4(void)
675 {
676 	unregister_tcf_proto_ops(&cls_route4_ops);
677 }
678 
679 module_init(init_route4)
680 module_exit(exit_route4)
681 MODULE_LICENSE("GPL");
682