xref: /openbmc/linux/net/sched/cls_route.c (revision 1c2dd16a) 
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 
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 unsigned long 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 0;
229 
230 	h2 = from_hash(handle >> 16);
231 	if (h2 > 32)
232 		return 0;
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 (unsigned long)f;
241 	}
242 	return 0;
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 rcu_head *head)
258 {
259 	struct route4_filter *f = container_of(head, struct route4_filter, rcu);
260 
261 	tcf_exts_destroy(&f->exts);
262 	kfree(f);
263 }
264 
265 static void route4_destroy(struct tcf_proto *tp)
266 {
267 	struct route4_head *head = rtnl_dereference(tp->root);
268 	int h1, h2;
269 
270 	if (head == NULL)
271 		return;
272 
273 	for (h1 = 0; h1 <= 256; h1++) {
274 		struct route4_bucket *b;
275 
276 		b = rtnl_dereference(head->table[h1]);
277 		if (b) {
278 			for (h2 = 0; h2 <= 32; h2++) {
279 				struct route4_filter *f;
280 
281 				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
282 					struct route4_filter *next;
283 
284 					next = rtnl_dereference(f->next);
285 					RCU_INIT_POINTER(b->ht[h2], next);
286 					tcf_unbind_filter(tp, &f->res);
287 					call_rcu(&f->rcu, route4_delete_filter);
288 				}
289 			}
290 			RCU_INIT_POINTER(head->table[h1], NULL);
291 			kfree_rcu(b, rcu);
292 		}
293 	}
294 	kfree_rcu(head, rcu);
295 }
296 
297 static int route4_delete(struct tcf_proto *tp, unsigned long arg, bool *last)
298 {
299 	struct route4_head *head = rtnl_dereference(tp->root);
300 	struct route4_filter *f = (struct route4_filter *)arg;
301 	struct route4_filter __rcu **fp;
302 	struct route4_filter *nf;
303 	struct route4_bucket *b;
304 	unsigned int h = 0;
305 	int i, h1;
306 
307 	if (!head || !f)
308 		return -EINVAL;
309 
310 	h = f->handle;
311 	b = f->bkt;
312 
313 	fp = &b->ht[from_hash(h >> 16)];
314 	for (nf = rtnl_dereference(*fp); nf;
315 	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
316 		if (nf == f) {
317 			/* unlink it */
318 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
319 
320 			/* Remove any fastmap lookups that might ref filter
321 			 * notice we unlink'd the filter so we can't get it
322 			 * back in the fastmap.
323 			 */
324 			route4_reset_fastmap(head);
325 
326 			/* Delete it */
327 			tcf_unbind_filter(tp, &f->res);
328 			call_rcu(&f->rcu, route4_delete_filter);
329 
330 			/* Strip RTNL protected tree */
331 			for (i = 0; i <= 32; i++) {
332 				struct route4_filter *rt;
333 
334 				rt = rtnl_dereference(b->ht[i]);
335 				if (rt)
336 					goto out;
337 			}
338 
339 			/* OK, session has no flows */
340 			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
341 			kfree_rcu(b, rcu);
342 			break;
343 		}
344 	}
345 
346 out:
347 	*last = true;
348 	for (h1 = 0; h1 <= 256; h1++) {
349 		if (rcu_access_pointer(head->table[h1])) {
350 			*last = false;
351 			break;
352 		}
353 	}
354 
355 	return 0;
356 }
357 
358 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
359 	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
360 	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
361 	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
362 	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
363 };
364 
365 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
366 			    unsigned long base, struct route4_filter *f,
367 			    u32 handle, struct route4_head *head,
368 			    struct nlattr **tb, struct nlattr *est, int new,
369 			    bool ovr)
370 {
371 	u32 id = 0, to = 0, nhandle = 0x8000;
372 	struct route4_filter *fp;
373 	unsigned int h1;
374 	struct route4_bucket *b;
375 	struct tcf_exts e;
376 	int err;
377 
378 	err = tcf_exts_init(&e, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
379 	if (err < 0)
380 		return err;
381 	err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
382 	if (err < 0)
383 		goto errout;
384 
385 	err = -EINVAL;
386 	if (tb[TCA_ROUTE4_TO]) {
387 		if (new && handle & 0x8000)
388 			goto errout;
389 		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
390 		if (to > 0xFF)
391 			goto errout;
392 		nhandle = to;
393 	}
394 
395 	if (tb[TCA_ROUTE4_FROM]) {
396 		if (tb[TCA_ROUTE4_IIF])
397 			goto errout;
398 		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
399 		if (id > 0xFF)
400 			goto errout;
401 		nhandle |= id << 16;
402 	} else if (tb[TCA_ROUTE4_IIF]) {
403 		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
404 		if (id > 0x7FFF)
405 			goto errout;
406 		nhandle |= (id | 0x8000) << 16;
407 	} else
408 		nhandle |= 0xFFFF << 16;
409 
410 	if (handle && new) {
411 		nhandle |= handle & 0x7F00;
412 		if (nhandle != handle)
413 			goto errout;
414 	}
415 
416 	h1 = to_hash(nhandle);
417 	b = rtnl_dereference(head->table[h1]);
418 	if (!b) {
419 		err = -ENOBUFS;
420 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
421 		if (b == NULL)
422 			goto errout;
423 
424 		rcu_assign_pointer(head->table[h1], b);
425 	} else {
426 		unsigned int h2 = from_hash(nhandle >> 16);
427 
428 		err = -EEXIST;
429 		for (fp = rtnl_dereference(b->ht[h2]);
430 		     fp;
431 		     fp = rtnl_dereference(fp->next))
432 			if (fp->handle == f->handle)
433 				goto errout;
434 	}
435 
436 	if (tb[TCA_ROUTE4_TO])
437 		f->id = to;
438 
439 	if (tb[TCA_ROUTE4_FROM])
440 		f->id = to | id<<16;
441 	else if (tb[TCA_ROUTE4_IIF])
442 		f->iif = id;
443 
444 	f->handle = nhandle;
445 	f->bkt = b;
446 	f->tp = tp;
447 
448 	if (tb[TCA_ROUTE4_CLASSID]) {
449 		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
450 		tcf_bind_filter(tp, &f->res, base);
451 	}
452 
453 	tcf_exts_change(tp, &f->exts, &e);
454 
455 	return 0;
456 errout:
457 	tcf_exts_destroy(&e);
458 	return err;
459 }
460 
461 static int route4_change(struct net *net, struct sk_buff *in_skb,
462 			 struct tcf_proto *tp, unsigned long base, u32 handle,
463 			 struct nlattr **tca, unsigned long *arg, bool ovr)
464 {
465 	struct route4_head *head = rtnl_dereference(tp->root);
466 	struct route4_filter __rcu **fp;
467 	struct route4_filter *fold, *f1, *pfp, *f = NULL;
468 	struct route4_bucket *b;
469 	struct nlattr *opt = tca[TCA_OPTIONS];
470 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
471 	unsigned int h, th;
472 	int err;
473 	bool new = true;
474 
475 	if (opt == NULL)
476 		return handle ? -EINVAL : 0;
477 
478 	err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy, NULL);
479 	if (err < 0)
480 		return err;
481 
482 	fold = (struct route4_filter *)*arg;
483 	if (fold && handle && fold->handle != handle)
484 			return -EINVAL;
485 
486 	err = -ENOBUFS;
487 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
488 	if (!f)
489 		goto errout;
490 
491 	err = tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
492 	if (err < 0)
493 		goto errout;
494 
495 	if (fold) {
496 		f->id = fold->id;
497 		f->iif = fold->iif;
498 		f->res = fold->res;
499 		f->handle = fold->handle;
500 
501 		f->tp = fold->tp;
502 		f->bkt = fold->bkt;
503 		new = false;
504 	}
505 
506 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
507 			       tca[TCA_RATE], new, ovr);
508 	if (err < 0)
509 		goto errout;
510 
511 	h = from_hash(f->handle >> 16);
512 	fp = &f->bkt->ht[h];
513 	for (pfp = rtnl_dereference(*fp);
514 	     (f1 = rtnl_dereference(*fp)) != NULL;
515 	     fp = &f1->next)
516 		if (f->handle < f1->handle)
517 			break;
518 
519 	netif_keep_dst(qdisc_dev(tp->q));
520 	rcu_assign_pointer(f->next, f1);
521 	rcu_assign_pointer(*fp, f);
522 
523 	if (fold && fold->handle && f->handle != fold->handle) {
524 		th = to_hash(fold->handle);
525 		h = from_hash(fold->handle >> 16);
526 		b = rtnl_dereference(head->table[th]);
527 		if (b) {
528 			fp = &b->ht[h];
529 			for (pfp = rtnl_dereference(*fp); pfp;
530 			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
531 				if (pfp == f) {
532 					*fp = f->next;
533 					break;
534 				}
535 			}
536 		}
537 	}
538 
539 	route4_reset_fastmap(head);
540 	*arg = (unsigned long)f;
541 	if (fold) {
542 		tcf_unbind_filter(tp, &fold->res);
543 		call_rcu(&fold->rcu, route4_delete_filter);
544 	}
545 	return 0;
546 
547 errout:
548 	if (f)
549 		tcf_exts_destroy(&f->exts);
550 	kfree(f);
551 	return err;
552 }
553 
554 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
555 {
556 	struct route4_head *head = rtnl_dereference(tp->root);
557 	unsigned int h, h1;
558 
559 	if (head == NULL)
560 		arg->stop = 1;
561 
562 	if (arg->stop)
563 		return;
564 
565 	for (h = 0; h <= 256; h++) {
566 		struct route4_bucket *b = rtnl_dereference(head->table[h]);
567 
568 		if (b) {
569 			for (h1 = 0; h1 <= 32; h1++) {
570 				struct route4_filter *f;
571 
572 				for (f = rtnl_dereference(b->ht[h1]);
573 				     f;
574 				     f = rtnl_dereference(f->next)) {
575 					if (arg->count < arg->skip) {
576 						arg->count++;
577 						continue;
578 					}
579 					if (arg->fn(tp, (unsigned long)f, arg) < 0) {
580 						arg->stop = 1;
581 						return;
582 					}
583 					arg->count++;
584 				}
585 			}
586 		}
587 	}
588 }
589 
590 static int route4_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
591 		       struct sk_buff *skb, struct tcmsg *t)
592 {
593 	struct route4_filter *f = (struct route4_filter *)fh;
594 	struct nlattr *nest;
595 	u32 id;
596 
597 	if (f == NULL)
598 		return skb->len;
599 
600 	t->tcm_handle = f->handle;
601 
602 	nest = nla_nest_start(skb, TCA_OPTIONS);
603 	if (nest == NULL)
604 		goto nla_put_failure;
605 
606 	if (!(f->handle & 0x8000)) {
607 		id = f->id & 0xFF;
608 		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
609 			goto nla_put_failure;
610 	}
611 	if (f->handle & 0x80000000) {
612 		if ((f->handle >> 16) != 0xFFFF &&
613 		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
614 			goto nla_put_failure;
615 	} else {
616 		id = f->id >> 16;
617 		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
618 			goto nla_put_failure;
619 	}
620 	if (f->res.classid &&
621 	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
622 		goto nla_put_failure;
623 
624 	if (tcf_exts_dump(skb, &f->exts) < 0)
625 		goto nla_put_failure;
626 
627 	nla_nest_end(skb, nest);
628 
629 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
630 		goto nla_put_failure;
631 
632 	return skb->len;
633 
634 nla_put_failure:
635 	nla_nest_cancel(skb, nest);
636 	return -1;
637 }
638 
639 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
640 	.kind		=	"route",
641 	.classify	=	route4_classify,
642 	.init		=	route4_init,
643 	.destroy	=	route4_destroy,
644 	.get		=	route4_get,
645 	.change		=	route4_change,
646 	.delete		=	route4_delete,
647 	.walk		=	route4_walk,
648 	.dump		=	route4_dump,
649 	.owner		=	THIS_MODULE,
650 };
651 
652 static int __init init_route4(void)
653 {
654 	return register_tcf_proto_ops(&cls_route4_ops);
655 }
656 
657 static void __exit exit_route4(void)
658 {
659 	unregister_tcf_proto_ops(&cls_route4_ops);
660 }
661 
662 module_init(init_route4)
663 module_exit(exit_route4)
664 MODULE_LICENSE("GPL");
665