xref: /linux/net/sched/cls_route.c (revision 24bce201d79807b668bf9d9e0aca801c5c0d5f78) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * net/sched/cls_route.c	ROUTE4 classifier.
4  *
5  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6  */
7 
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13 #include <linux/errno.h>
14 #include <linux/skbuff.h>
15 #include <net/dst.h>
16 #include <net/route.h>
17 #include <net/netlink.h>
18 #include <net/act_api.h>
19 #include <net/pkt_cls.h>
20 
21 /*
22  * 1. For now we assume that route tags < 256.
23  *    It allows to use direct table lookups, instead of hash tables.
24  * 2. For now we assume that "from TAG" and "fromdev DEV" statements
25  *    are mutually  exclusive.
26  * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
27  */
28 struct route4_fastmap {
29 	struct route4_filter		*filter;
30 	u32				id;
31 	int				iif;
32 };
33 
34 struct route4_head {
35 	struct route4_fastmap		fastmap[16];
36 	struct route4_bucket __rcu	*table[256 + 1];
37 	struct rcu_head			rcu;
38 };
39 
40 struct route4_bucket {
41 	/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
42 	struct route4_filter __rcu	*ht[16 + 16 + 1];
43 	struct rcu_head			rcu;
44 };
45 
46 struct route4_filter {
47 	struct route4_filter __rcu	*next;
48 	u32			id;
49 	int			iif;
50 
51 	struct tcf_result	res;
52 	struct tcf_exts		exts;
53 	u32			handle;
54 	struct route4_bucket	*bkt;
55 	struct tcf_proto	*tp;
56 	struct rcu_work		rwork;
57 };
58 
59 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
60 
61 static inline int route4_fastmap_hash(u32 id, int iif)
62 {
63 	return id & 0xF;
64 }
65 
66 static DEFINE_SPINLOCK(fastmap_lock);
67 static void
68 route4_reset_fastmap(struct route4_head *head)
69 {
70 	spin_lock_bh(&fastmap_lock);
71 	memset(head->fastmap, 0, sizeof(head->fastmap));
72 	spin_unlock_bh(&fastmap_lock);
73 }
74 
75 static void
76 route4_set_fastmap(struct route4_head *head, u32 id, int iif,
77 		   struct route4_filter *f)
78 {
79 	int h = route4_fastmap_hash(id, iif);
80 
81 	/* fastmap updates must look atomic to aling id, iff, filter */
82 	spin_lock_bh(&fastmap_lock);
83 	head->fastmap[h].id = id;
84 	head->fastmap[h].iif = iif;
85 	head->fastmap[h].filter = f;
86 	spin_unlock_bh(&fastmap_lock);
87 }
88 
89 static inline int route4_hash_to(u32 id)
90 {
91 	return id & 0xFF;
92 }
93 
94 static inline int route4_hash_from(u32 id)
95 {
96 	return (id >> 16) & 0xF;
97 }
98 
99 static inline int route4_hash_iif(int iif)
100 {
101 	return 16 + ((iif >> 16) & 0xF);
102 }
103 
104 static inline int route4_hash_wild(void)
105 {
106 	return 32;
107 }
108 
109 #define ROUTE4_APPLY_RESULT()					\
110 {								\
111 	*res = f->res;						\
112 	if (tcf_exts_has_actions(&f->exts)) {			\
113 		int r = tcf_exts_exec(skb, &f->exts, res);	\
114 		if (r < 0) {					\
115 			dont_cache = 1;				\
116 			continue;				\
117 		}						\
118 		return r;					\
119 	} else if (!dont_cache)					\
120 		route4_set_fastmap(head, id, iif, f);		\
121 	return 0;						\
122 }
123 
124 static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
125 			   struct tcf_result *res)
126 {
127 	struct route4_head *head = rcu_dereference_bh(tp->root);
128 	struct dst_entry *dst;
129 	struct route4_bucket *b;
130 	struct route4_filter *f;
131 	u32 id, h;
132 	int iif, dont_cache = 0;
133 
134 	dst = skb_dst(skb);
135 	if (!dst)
136 		goto failure;
137 
138 	id = dst->tclassid;
139 
140 	iif = inet_iif(skb);
141 
142 	h = route4_fastmap_hash(id, iif);
143 
144 	spin_lock(&fastmap_lock);
145 	if (id == head->fastmap[h].id &&
146 	    iif == head->fastmap[h].iif &&
147 	    (f = head->fastmap[h].filter) != NULL) {
148 		if (f == ROUTE4_FAILURE) {
149 			spin_unlock(&fastmap_lock);
150 			goto failure;
151 		}
152 
153 		*res = f->res;
154 		spin_unlock(&fastmap_lock);
155 		return 0;
156 	}
157 	spin_unlock(&fastmap_lock);
158 
159 	h = route4_hash_to(id);
160 
161 restart:
162 	b = rcu_dereference_bh(head->table[h]);
163 	if (b) {
164 		for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
165 		     f;
166 		     f = rcu_dereference_bh(f->next))
167 			if (f->id == id)
168 				ROUTE4_APPLY_RESULT();
169 
170 		for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
171 		     f;
172 		     f = rcu_dereference_bh(f->next))
173 			if (f->iif == iif)
174 				ROUTE4_APPLY_RESULT();
175 
176 		for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
177 		     f;
178 		     f = rcu_dereference_bh(f->next))
179 			ROUTE4_APPLY_RESULT();
180 	}
181 	if (h < 256) {
182 		h = 256;
183 		id &= ~0xFFFF;
184 		goto restart;
185 	}
186 
187 	if (!dont_cache)
188 		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
189 failure:
190 	return -1;
191 }
192 
193 static inline u32 to_hash(u32 id)
194 {
195 	u32 h = id & 0xFF;
196 
197 	if (id & 0x8000)
198 		h += 256;
199 	return h;
200 }
201 
202 static inline u32 from_hash(u32 id)
203 {
204 	id &= 0xFFFF;
205 	if (id == 0xFFFF)
206 		return 32;
207 	if (!(id & 0x8000)) {
208 		if (id > 255)
209 			return 256;
210 		return id & 0xF;
211 	}
212 	return 16 + (id & 0xF);
213 }
214 
215 static void *route4_get(struct tcf_proto *tp, u32 handle)
216 {
217 	struct route4_head *head = rtnl_dereference(tp->root);
218 	struct route4_bucket *b;
219 	struct route4_filter *f;
220 	unsigned int h1, h2;
221 
222 	h1 = to_hash(handle);
223 	if (h1 > 256)
224 		return NULL;
225 
226 	h2 = from_hash(handle >> 16);
227 	if (h2 > 32)
228 		return NULL;
229 
230 	b = rtnl_dereference(head->table[h1]);
231 	if (b) {
232 		for (f = rtnl_dereference(b->ht[h2]);
233 		     f;
234 		     f = rtnl_dereference(f->next))
235 			if (f->handle == handle)
236 				return f;
237 	}
238 	return NULL;
239 }
240 
241 static int route4_init(struct tcf_proto *tp)
242 {
243 	struct route4_head *head;
244 
245 	head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
246 	if (head == NULL)
247 		return -ENOBUFS;
248 
249 	rcu_assign_pointer(tp->root, head);
250 	return 0;
251 }
252 
253 static void __route4_delete_filter(struct route4_filter *f)
254 {
255 	tcf_exts_destroy(&f->exts);
256 	tcf_exts_put_net(&f->exts);
257 	kfree(f);
258 }
259 
260 static void route4_delete_filter_work(struct work_struct *work)
261 {
262 	struct route4_filter *f = container_of(to_rcu_work(work),
263 					       struct route4_filter,
264 					       rwork);
265 	rtnl_lock();
266 	__route4_delete_filter(f);
267 	rtnl_unlock();
268 }
269 
270 static void route4_queue_work(struct route4_filter *f)
271 {
272 	tcf_queue_work(&f->rwork, route4_delete_filter_work);
273 }
274 
275 static void route4_destroy(struct tcf_proto *tp, bool rtnl_held,
276 			   struct netlink_ext_ack *extack)
277 {
278 	struct route4_head *head = rtnl_dereference(tp->root);
279 	int h1, h2;
280 
281 	if (head == NULL)
282 		return;
283 
284 	for (h1 = 0; h1 <= 256; h1++) {
285 		struct route4_bucket *b;
286 
287 		b = rtnl_dereference(head->table[h1]);
288 		if (b) {
289 			for (h2 = 0; h2 <= 32; h2++) {
290 				struct route4_filter *f;
291 
292 				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
293 					struct route4_filter *next;
294 
295 					next = rtnl_dereference(f->next);
296 					RCU_INIT_POINTER(b->ht[h2], next);
297 					tcf_unbind_filter(tp, &f->res);
298 					if (tcf_exts_get_net(&f->exts))
299 						route4_queue_work(f);
300 					else
301 						__route4_delete_filter(f);
302 				}
303 			}
304 			RCU_INIT_POINTER(head->table[h1], NULL);
305 			kfree_rcu(b, rcu);
306 		}
307 	}
308 	kfree_rcu(head, rcu);
309 }
310 
311 static int route4_delete(struct tcf_proto *tp, void *arg, bool *last,
312 			 bool rtnl_held, struct netlink_ext_ack *extack)
313 {
314 	struct route4_head *head = rtnl_dereference(tp->root);
315 	struct route4_filter *f = arg;
316 	struct route4_filter __rcu **fp;
317 	struct route4_filter *nf;
318 	struct route4_bucket *b;
319 	unsigned int h = 0;
320 	int i, h1;
321 
322 	if (!head || !f)
323 		return -EINVAL;
324 
325 	h = f->handle;
326 	b = f->bkt;
327 
328 	fp = &b->ht[from_hash(h >> 16)];
329 	for (nf = rtnl_dereference(*fp); nf;
330 	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
331 		if (nf == f) {
332 			/* unlink it */
333 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
334 
335 			/* Remove any fastmap lookups that might ref filter
336 			 * notice we unlink'd the filter so we can't get it
337 			 * back in the fastmap.
338 			 */
339 			route4_reset_fastmap(head);
340 
341 			/* Delete it */
342 			tcf_unbind_filter(tp, &f->res);
343 			tcf_exts_get_net(&f->exts);
344 			tcf_queue_work(&f->rwork, route4_delete_filter_work);
345 
346 			/* Strip RTNL protected tree */
347 			for (i = 0; i <= 32; i++) {
348 				struct route4_filter *rt;
349 
350 				rt = rtnl_dereference(b->ht[i]);
351 				if (rt)
352 					goto out;
353 			}
354 
355 			/* OK, session has no flows */
356 			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
357 			kfree_rcu(b, rcu);
358 			break;
359 		}
360 	}
361 
362 out:
363 	*last = true;
364 	for (h1 = 0; h1 <= 256; h1++) {
365 		if (rcu_access_pointer(head->table[h1])) {
366 			*last = false;
367 			break;
368 		}
369 	}
370 
371 	return 0;
372 }
373 
374 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
375 	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
376 	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
377 	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
378 	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
379 };
380 
381 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
382 			    unsigned long base, struct route4_filter *f,
383 			    u32 handle, struct route4_head *head,
384 			    struct nlattr **tb, struct nlattr *est, int new,
385 			    u32 flags, struct netlink_ext_ack *extack)
386 {
387 	u32 id = 0, to = 0, nhandle = 0x8000;
388 	struct route4_filter *fp;
389 	unsigned int h1;
390 	struct route4_bucket *b;
391 	int err;
392 
393 	err = tcf_exts_validate(net, tp, tb, est, &f->exts, flags, extack);
394 	if (err < 0)
395 		return err;
396 
397 	if (tb[TCA_ROUTE4_TO]) {
398 		if (new && handle & 0x8000)
399 			return -EINVAL;
400 		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
401 		if (to > 0xFF)
402 			return -EINVAL;
403 		nhandle = to;
404 	}
405 
406 	if (tb[TCA_ROUTE4_FROM]) {
407 		if (tb[TCA_ROUTE4_IIF])
408 			return -EINVAL;
409 		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
410 		if (id > 0xFF)
411 			return -EINVAL;
412 		nhandle |= id << 16;
413 	} else if (tb[TCA_ROUTE4_IIF]) {
414 		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
415 		if (id > 0x7FFF)
416 			return -EINVAL;
417 		nhandle |= (id | 0x8000) << 16;
418 	} else
419 		nhandle |= 0xFFFF << 16;
420 
421 	if (handle && new) {
422 		nhandle |= handle & 0x7F00;
423 		if (nhandle != handle)
424 			return -EINVAL;
425 	}
426 
427 	h1 = to_hash(nhandle);
428 	b = rtnl_dereference(head->table[h1]);
429 	if (!b) {
430 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
431 		if (b == NULL)
432 			return -ENOBUFS;
433 
434 		rcu_assign_pointer(head->table[h1], b);
435 	} else {
436 		unsigned int h2 = from_hash(nhandle >> 16);
437 
438 		for (fp = rtnl_dereference(b->ht[h2]);
439 		     fp;
440 		     fp = rtnl_dereference(fp->next))
441 			if (fp->handle == f->handle)
442 				return -EEXIST;
443 	}
444 
445 	if (tb[TCA_ROUTE4_TO])
446 		f->id = to;
447 
448 	if (tb[TCA_ROUTE4_FROM])
449 		f->id = to | id<<16;
450 	else if (tb[TCA_ROUTE4_IIF])
451 		f->iif = id;
452 
453 	f->handle = nhandle;
454 	f->bkt = b;
455 	f->tp = tp;
456 
457 	if (tb[TCA_ROUTE4_CLASSID]) {
458 		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
459 		tcf_bind_filter(tp, &f->res, base);
460 	}
461 
462 	return 0;
463 }
464 
465 static int route4_change(struct net *net, struct sk_buff *in_skb,
466 			 struct tcf_proto *tp, unsigned long base, u32 handle,
467 			 struct nlattr **tca, void **arg, u32 flags,
468 			 struct netlink_ext_ack *extack)
469 {
470 	struct route4_head *head = rtnl_dereference(tp->root);
471 	struct route4_filter __rcu **fp;
472 	struct route4_filter *fold, *f1, *pfp, *f = NULL;
473 	struct route4_bucket *b;
474 	struct nlattr *opt = tca[TCA_OPTIONS];
475 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
476 	unsigned int h, th;
477 	int err;
478 	bool new = true;
479 
480 	if (opt == NULL)
481 		return handle ? -EINVAL : 0;
482 
483 	err = nla_parse_nested_deprecated(tb, TCA_ROUTE4_MAX, opt,
484 					  route4_policy, NULL);
485 	if (err < 0)
486 		return err;
487 
488 	fold = *arg;
489 	if (fold && handle && fold->handle != handle)
490 			return -EINVAL;
491 
492 	err = -ENOBUFS;
493 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
494 	if (!f)
495 		goto errout;
496 
497 	err = tcf_exts_init(&f->exts, net, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
498 	if (err < 0)
499 		goto errout;
500 
501 	if (fold) {
502 		f->id = fold->id;
503 		f->iif = fold->iif;
504 		f->res = fold->res;
505 		f->handle = fold->handle;
506 
507 		f->tp = fold->tp;
508 		f->bkt = fold->bkt;
509 		new = false;
510 	}
511 
512 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
513 			       tca[TCA_RATE], new, flags, extack);
514 	if (err < 0)
515 		goto errout;
516 
517 	h = from_hash(f->handle >> 16);
518 	fp = &f->bkt->ht[h];
519 	for (pfp = rtnl_dereference(*fp);
520 	     (f1 = rtnl_dereference(*fp)) != NULL;
521 	     fp = &f1->next)
522 		if (f->handle < f1->handle)
523 			break;
524 
525 	tcf_block_netif_keep_dst(tp->chain->block);
526 	rcu_assign_pointer(f->next, f1);
527 	rcu_assign_pointer(*fp, f);
528 
529 	if (fold && fold->handle && f->handle != fold->handle) {
530 		th = to_hash(fold->handle);
531 		h = from_hash(fold->handle >> 16);
532 		b = rtnl_dereference(head->table[th]);
533 		if (b) {
534 			fp = &b->ht[h];
535 			for (pfp = rtnl_dereference(*fp); pfp;
536 			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
537 				if (pfp == fold) {
538 					rcu_assign_pointer(*fp, fold->next);
539 					break;
540 				}
541 			}
542 		}
543 	}
544 
545 	route4_reset_fastmap(head);
546 	*arg = f;
547 	if (fold) {
548 		tcf_unbind_filter(tp, &fold->res);
549 		tcf_exts_get_net(&fold->exts);
550 		tcf_queue_work(&fold->rwork, route4_delete_filter_work);
551 	}
552 	return 0;
553 
554 errout:
555 	if (f)
556 		tcf_exts_destroy(&f->exts);
557 	kfree(f);
558 	return err;
559 }
560 
561 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
562 			bool rtnl_held)
563 {
564 	struct route4_head *head = rtnl_dereference(tp->root);
565 	unsigned int h, h1;
566 
567 	if (head == NULL || arg->stop)
568 		return;
569 
570 	for (h = 0; h <= 256; h++) {
571 		struct route4_bucket *b = rtnl_dereference(head->table[h]);
572 
573 		if (b) {
574 			for (h1 = 0; h1 <= 32; h1++) {
575 				struct route4_filter *f;
576 
577 				for (f = rtnl_dereference(b->ht[h1]);
578 				     f;
579 				     f = rtnl_dereference(f->next)) {
580 					if (arg->count < arg->skip) {
581 						arg->count++;
582 						continue;
583 					}
584 					if (arg->fn(tp, f, arg) < 0) {
585 						arg->stop = 1;
586 						return;
587 					}
588 					arg->count++;
589 				}
590 			}
591 		}
592 	}
593 }
594 
595 static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
596 		       struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
597 {
598 	struct route4_filter *f = fh;
599 	struct nlattr *nest;
600 	u32 id;
601 
602 	if (f == NULL)
603 		return skb->len;
604 
605 	t->tcm_handle = f->handle;
606 
607 	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
608 	if (nest == NULL)
609 		goto nla_put_failure;
610 
611 	if (!(f->handle & 0x8000)) {
612 		id = f->id & 0xFF;
613 		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
614 			goto nla_put_failure;
615 	}
616 	if (f->handle & 0x80000000) {
617 		if ((f->handle >> 16) != 0xFFFF &&
618 		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
619 			goto nla_put_failure;
620 	} else {
621 		id = f->id >> 16;
622 		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
623 			goto nla_put_failure;
624 	}
625 	if (f->res.classid &&
626 	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
627 		goto nla_put_failure;
628 
629 	if (tcf_exts_dump(skb, &f->exts) < 0)
630 		goto nla_put_failure;
631 
632 	nla_nest_end(skb, nest);
633 
634 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
635 		goto nla_put_failure;
636 
637 	return skb->len;
638 
639 nla_put_failure:
640 	nla_nest_cancel(skb, nest);
641 	return -1;
642 }
643 
644 static void route4_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
645 			      unsigned long base)
646 {
647 	struct route4_filter *f = fh;
648 
649 	if (f && f->res.classid == classid) {
650 		if (cl)
651 			__tcf_bind_filter(q, &f->res, base);
652 		else
653 			__tcf_unbind_filter(q, &f->res);
654 	}
655 }
656 
657 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
658 	.kind		=	"route",
659 	.classify	=	route4_classify,
660 	.init		=	route4_init,
661 	.destroy	=	route4_destroy,
662 	.get		=	route4_get,
663 	.change		=	route4_change,
664 	.delete		=	route4_delete,
665 	.walk		=	route4_walk,
666 	.dump		=	route4_dump,
667 	.bind_class	=	route4_bind_class,
668 	.owner		=	THIS_MODULE,
669 };
670 
671 static int __init init_route4(void)
672 {
673 	return register_tcf_proto_ops(&cls_route4_ops);
674 }
675 
676 static void __exit exit_route4(void)
677 {
678 	unregister_tcf_proto_ops(&cls_route4_ops);
679 }
680 
681 module_init(init_route4)
682 module_exit(exit_route4)
683 MODULE_LICENSE("GPL");
684