xref: /linux/net/sched/cls_route.c (revision d6a5c562214f26e442c8ec3ff1e28e16675d1bcf) 
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 	if (!nhandle) {
428 		NL_SET_ERR_MSG(extack, "Replacing with handle of 0 is invalid");
429 		return -EINVAL;
430 	}
431 
432 	h1 = to_hash(nhandle);
433 	b = rtnl_dereference(head->table[h1]);
434 	if (!b) {
435 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
436 		if (b == NULL)
437 			return -ENOBUFS;
438 
439 		rcu_assign_pointer(head->table[h1], b);
440 	} else {
441 		unsigned int h2 = from_hash(nhandle >> 16);
442 
443 		for (fp = rtnl_dereference(b->ht[h2]);
444 		     fp;
445 		     fp = rtnl_dereference(fp->next))
446 			if (fp->handle == f->handle)
447 				return -EEXIST;
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 	return 0;
468 }
469 
470 static int route4_change(struct net *net, struct sk_buff *in_skb,
471 			 struct tcf_proto *tp, unsigned long base, u32 handle,
472 			 struct nlattr **tca, void **arg, u32 flags,
473 			 struct netlink_ext_ack *extack)
474 {
475 	struct route4_head *head = rtnl_dereference(tp->root);
476 	struct route4_filter __rcu **fp;
477 	struct route4_filter *fold, *f1, *pfp, *f = NULL;
478 	struct route4_bucket *b;
479 	struct nlattr *opt = tca[TCA_OPTIONS];
480 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
481 	unsigned int h, th;
482 	int err;
483 	bool new = true;
484 
485 	if (!handle) {
486 		NL_SET_ERR_MSG(extack, "Creating with handle of 0 is invalid");
487 		return -EINVAL;
488 	}
489 
490 	if (opt == NULL)
491 		return -EINVAL;
492 
493 	err = nla_parse_nested_deprecated(tb, TCA_ROUTE4_MAX, opt,
494 					  route4_policy, NULL);
495 	if (err < 0)
496 		return err;
497 
498 	fold = *arg;
499 	if (fold && fold->handle != handle)
500 			return -EINVAL;
501 
502 	err = -ENOBUFS;
503 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
504 	if (!f)
505 		goto errout;
506 
507 	err = tcf_exts_init(&f->exts, net, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
508 	if (err < 0)
509 		goto errout;
510 
511 	if (fold) {
512 		f->id = fold->id;
513 		f->iif = fold->iif;
514 		f->res = fold->res;
515 		f->handle = fold->handle;
516 
517 		f->tp = fold->tp;
518 		f->bkt = fold->bkt;
519 		new = false;
520 	}
521 
522 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
523 			       tca[TCA_RATE], new, flags, extack);
524 	if (err < 0)
525 		goto errout;
526 
527 	h = from_hash(f->handle >> 16);
528 	fp = &f->bkt->ht[h];
529 	for (pfp = rtnl_dereference(*fp);
530 	     (f1 = rtnl_dereference(*fp)) != NULL;
531 	     fp = &f1->next)
532 		if (f->handle < f1->handle)
533 			break;
534 
535 	tcf_block_netif_keep_dst(tp->chain->block);
536 	rcu_assign_pointer(f->next, f1);
537 	rcu_assign_pointer(*fp, f);
538 
539 	if (fold) {
540 		th = to_hash(fold->handle);
541 		h = from_hash(fold->handle >> 16);
542 		b = rtnl_dereference(head->table[th]);
543 		if (b) {
544 			fp = &b->ht[h];
545 			for (pfp = rtnl_dereference(*fp); pfp;
546 			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
547 				if (pfp == fold) {
548 					rcu_assign_pointer(*fp, fold->next);
549 					break;
550 				}
551 			}
552 		}
553 	}
554 
555 	route4_reset_fastmap(head);
556 	*arg = f;
557 	if (fold) {
558 		tcf_unbind_filter(tp, &fold->res);
559 		tcf_exts_get_net(&fold->exts);
560 		tcf_queue_work(&fold->rwork, route4_delete_filter_work);
561 	}
562 	return 0;
563 
564 errout:
565 	if (f)
566 		tcf_exts_destroy(&f->exts);
567 	kfree(f);
568 	return err;
569 }
570 
571 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
572 			bool rtnl_held)
573 {
574 	struct route4_head *head = rtnl_dereference(tp->root);
575 	unsigned int h, h1;
576 
577 	if (head == NULL || arg->stop)
578 		return;
579 
580 	for (h = 0; h <= 256; h++) {
581 		struct route4_bucket *b = rtnl_dereference(head->table[h]);
582 
583 		if (b) {
584 			for (h1 = 0; h1 <= 32; h1++) {
585 				struct route4_filter *f;
586 
587 				for (f = rtnl_dereference(b->ht[h1]);
588 				     f;
589 				     f = rtnl_dereference(f->next)) {
590 					if (!tc_cls_stats_dump(tp, arg, f))
591 						return;
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_noflag(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, void *q,
648 			      unsigned long base)
649 {
650 	struct route4_filter *f = fh;
651 
652 	tc_cls_bind_class(classid, cl, q, &f->res, base);
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