xref: /openbmc/linux/net/sched/cls_route.c (revision 12eb4683) 
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 
33 struct route4_fastmap {
34 	struct route4_filter	*filter;
35 	u32			id;
36 	int			iif;
37 };
38 
39 struct route4_head {
40 	struct route4_fastmap	fastmap[16];
41 	struct route4_bucket	*table[256 + 1];
42 };
43 
44 struct route4_bucket {
45 	/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
46 	struct route4_filter	*ht[16 + 16 + 1];
47 };
48 
49 struct route4_filter {
50 	struct route4_filter	*next;
51 	u32			id;
52 	int			iif;
53 
54 	struct tcf_result	res;
55 	struct tcf_exts		exts;
56 	u32			handle;
57 	struct route4_bucket	*bkt;
58 };
59 
60 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
61 
62 static const struct tcf_ext_map route_ext_map = {
63 	.police = TCA_ROUTE4_POLICE,
64 	.action = TCA_ROUTE4_ACT
65 };
66 
67 static inline int route4_fastmap_hash(u32 id, int iif)
68 {
69 	return id & 0xF;
70 }
71 
72 static void
73 route4_reset_fastmap(struct Qdisc *q, struct route4_head *head, u32 id)
74 {
75 	spinlock_t *root_lock = qdisc_root_sleeping_lock(q);
76 
77 	spin_lock_bh(root_lock);
78 	memset(head->fastmap, 0, sizeof(head->fastmap));
79 	spin_unlock_bh(root_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 	head->fastmap[h].id = id;
89 	head->fastmap[h].iif = iif;
90 	head->fastmap[h].filter = f;
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 = (struct route4_head *)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 	if (head == NULL)
144 		goto old_method;
145 
146 	iif = inet_iif(skb);
147 
148 	h = route4_fastmap_hash(id, iif);
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 			goto failure;
154 
155 		*res = f->res;
156 		return 0;
157 	}
158 
159 	h = route4_hash_to(id);
160 
161 restart:
162 	b = head->table[h];
163 	if (b) {
164 		for (f = b->ht[route4_hash_from(id)]; f; f = f->next)
165 			if (f->id == id)
166 				ROUTE4_APPLY_RESULT();
167 
168 		for (f = b->ht[route4_hash_iif(iif)]; f; f = f->next)
169 			if (f->iif == iif)
170 				ROUTE4_APPLY_RESULT();
171 
172 		for (f = b->ht[route4_hash_wild()]; f; f = f->next)
173 			ROUTE4_APPLY_RESULT();
174 
175 	}
176 	if (h < 256) {
177 		h = 256;
178 		id &= ~0xFFFF;
179 		goto restart;
180 	}
181 
182 	if (!dont_cache)
183 		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
184 failure:
185 	return -1;
186 
187 old_method:
188 	if (id && (TC_H_MAJ(id) == 0 ||
189 		   !(TC_H_MAJ(id^tp->q->handle)))) {
190 		res->classid = id;
191 		res->class = 0;
192 		return 0;
193 	}
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 = (struct route4_head *)tp->root;
222 	struct route4_bucket *b;
223 	struct route4_filter *f;
224 	unsigned int h1, h2;
225 
226 	if (!head)
227 		return 0;
228 
229 	h1 = to_hash(handle);
230 	if (h1 > 256)
231 		return 0;
232 
233 	h2 = from_hash(handle >> 16);
234 	if (h2 > 32)
235 		return 0;
236 
237 	b = head->table[h1];
238 	if (b) {
239 		for (f = b->ht[h2]; f; f = f->next)
240 			if (f->handle == handle)
241 				return (unsigned long)f;
242 	}
243 	return 0;
244 }
245 
246 static void route4_put(struct tcf_proto *tp, unsigned long f)
247 {
248 }
249 
250 static int route4_init(struct tcf_proto *tp)
251 {
252 	return 0;
253 }
254 
255 static void
256 route4_delete_filter(struct tcf_proto *tp, struct route4_filter *f)
257 {
258 	tcf_unbind_filter(tp, &f->res);
259 	tcf_exts_destroy(tp, &f->exts);
260 	kfree(f);
261 }
262 
263 static void route4_destroy(struct tcf_proto *tp)
264 {
265 	struct route4_head *head = tp->root;
266 	int h1, h2;
267 
268 	if (head == NULL)
269 		return;
270 
271 	for (h1 = 0; h1 <= 256; h1++) {
272 		struct route4_bucket *b;
273 
274 		b = head->table[h1];
275 		if (b) {
276 			for (h2 = 0; h2 <= 32; h2++) {
277 				struct route4_filter *f;
278 
279 				while ((f = b->ht[h2]) != NULL) {
280 					b->ht[h2] = f->next;
281 					route4_delete_filter(tp, f);
282 				}
283 			}
284 			kfree(b);
285 		}
286 	}
287 	kfree(head);
288 }
289 
290 static int route4_delete(struct tcf_proto *tp, unsigned long arg)
291 {
292 	struct route4_head *head = (struct route4_head *)tp->root;
293 	struct route4_filter **fp, *f = (struct route4_filter *)arg;
294 	unsigned int h = 0;
295 	struct route4_bucket *b;
296 	int i;
297 
298 	if (!head || !f)
299 		return -EINVAL;
300 
301 	h = f->handle;
302 	b = f->bkt;
303 
304 	for (fp = &b->ht[from_hash(h >> 16)]; *fp; fp = &(*fp)->next) {
305 		if (*fp == f) {
306 			tcf_tree_lock(tp);
307 			*fp = f->next;
308 			tcf_tree_unlock(tp);
309 
310 			route4_reset_fastmap(tp->q, head, f->id);
311 			route4_delete_filter(tp, f);
312 
313 			/* Strip tree */
314 
315 			for (i = 0; i <= 32; i++)
316 				if (b->ht[i])
317 					return 0;
318 
319 			/* OK, session has no flows */
320 			tcf_tree_lock(tp);
321 			head->table[to_hash(h)] = NULL;
322 			tcf_tree_unlock(tp);
323 
324 			kfree(b);
325 			return 0;
326 		}
327 	}
328 	return 0;
329 }
330 
331 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
332 	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
333 	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
334 	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
335 	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
336 };
337 
338 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
339 			    unsigned long base, struct route4_filter *f,
340 			    u32 handle, struct route4_head *head,
341 			    struct nlattr **tb, struct nlattr *est, int new)
342 {
343 	int err;
344 	u32 id = 0, to = 0, nhandle = 0x8000;
345 	struct route4_filter *fp;
346 	unsigned int h1;
347 	struct route4_bucket *b;
348 	struct tcf_exts e;
349 
350 	err = tcf_exts_validate(net, tp, tb, est, &e, &route_ext_map);
351 	if (err < 0)
352 		return err;
353 
354 	err = -EINVAL;
355 	if (tb[TCA_ROUTE4_TO]) {
356 		if (new && handle & 0x8000)
357 			goto errout;
358 		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
359 		if (to > 0xFF)
360 			goto errout;
361 		nhandle = to;
362 	}
363 
364 	if (tb[TCA_ROUTE4_FROM]) {
365 		if (tb[TCA_ROUTE4_IIF])
366 			goto errout;
367 		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
368 		if (id > 0xFF)
369 			goto errout;
370 		nhandle |= id << 16;
371 	} else if (tb[TCA_ROUTE4_IIF]) {
372 		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
373 		if (id > 0x7FFF)
374 			goto errout;
375 		nhandle |= (id | 0x8000) << 16;
376 	} else
377 		nhandle |= 0xFFFF << 16;
378 
379 	if (handle && new) {
380 		nhandle |= handle & 0x7F00;
381 		if (nhandle != handle)
382 			goto errout;
383 	}
384 
385 	h1 = to_hash(nhandle);
386 	b = head->table[h1];
387 	if (!b) {
388 		err = -ENOBUFS;
389 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
390 		if (b == NULL)
391 			goto errout;
392 
393 		tcf_tree_lock(tp);
394 		head->table[h1] = b;
395 		tcf_tree_unlock(tp);
396 	} else {
397 		unsigned int h2 = from_hash(nhandle >> 16);
398 
399 		err = -EEXIST;
400 		for (fp = b->ht[h2]; fp; fp = fp->next)
401 			if (fp->handle == f->handle)
402 				goto errout;
403 	}
404 
405 	tcf_tree_lock(tp);
406 	if (tb[TCA_ROUTE4_TO])
407 		f->id = to;
408 
409 	if (tb[TCA_ROUTE4_FROM])
410 		f->id = to | id<<16;
411 	else if (tb[TCA_ROUTE4_IIF])
412 		f->iif = id;
413 
414 	f->handle = nhandle;
415 	f->bkt = b;
416 	tcf_tree_unlock(tp);
417 
418 	if (tb[TCA_ROUTE4_CLASSID]) {
419 		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
420 		tcf_bind_filter(tp, &f->res, base);
421 	}
422 
423 	tcf_exts_change(tp, &f->exts, &e);
424 
425 	return 0;
426 errout:
427 	tcf_exts_destroy(tp, &e);
428 	return err;
429 }
430 
431 static int route4_change(struct net *net, struct sk_buff *in_skb,
432 		       struct tcf_proto *tp, unsigned long base,
433 		       u32 handle,
434 		       struct nlattr **tca,
435 		       unsigned long *arg)
436 {
437 	struct route4_head *head = tp->root;
438 	struct route4_filter *f, *f1, **fp;
439 	struct route4_bucket *b;
440 	struct nlattr *opt = tca[TCA_OPTIONS];
441 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
442 	unsigned int h, th;
443 	u32 old_handle = 0;
444 	int err;
445 
446 	if (opt == NULL)
447 		return handle ? -EINVAL : 0;
448 
449 	err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy);
450 	if (err < 0)
451 		return err;
452 
453 	f = (struct route4_filter *)*arg;
454 	if (f) {
455 		if (f->handle != handle && handle)
456 			return -EINVAL;
457 
458 		if (f->bkt)
459 			old_handle = f->handle;
460 
461 		err = route4_set_parms(net, tp, base, f, handle, head, tb,
462 			tca[TCA_RATE], 0);
463 		if (err < 0)
464 			return err;
465 
466 		goto reinsert;
467 	}
468 
469 	err = -ENOBUFS;
470 	if (head == NULL) {
471 		head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
472 		if (head == NULL)
473 			goto errout;
474 
475 		tcf_tree_lock(tp);
476 		tp->root = head;
477 		tcf_tree_unlock(tp);
478 	}
479 
480 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
481 	if (f == NULL)
482 		goto errout;
483 
484 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
485 		tca[TCA_RATE], 1);
486 	if (err < 0)
487 		goto errout;
488 
489 reinsert:
490 	h = from_hash(f->handle >> 16);
491 	for (fp = &f->bkt->ht[h]; (f1 = *fp) != NULL; fp = &f1->next)
492 		if (f->handle < f1->handle)
493 			break;
494 
495 	f->next = f1;
496 	tcf_tree_lock(tp);
497 	*fp = f;
498 
499 	if (old_handle && f->handle != old_handle) {
500 		th = to_hash(old_handle);
501 		h = from_hash(old_handle >> 16);
502 		b = head->table[th];
503 		if (b) {
504 			for (fp = &b->ht[h]; *fp; fp = &(*fp)->next) {
505 				if (*fp == f) {
506 					*fp = f->next;
507 					break;
508 				}
509 			}
510 		}
511 	}
512 	tcf_tree_unlock(tp);
513 
514 	route4_reset_fastmap(tp->q, head, f->id);
515 	*arg = (unsigned long)f;
516 	return 0;
517 
518 errout:
519 	kfree(f);
520 	return err;
521 }
522 
523 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
524 {
525 	struct route4_head *head = tp->root;
526 	unsigned int h, h1;
527 
528 	if (head == NULL)
529 		arg->stop = 1;
530 
531 	if (arg->stop)
532 		return;
533 
534 	for (h = 0; h <= 256; h++) {
535 		struct route4_bucket *b = head->table[h];
536 
537 		if (b) {
538 			for (h1 = 0; h1 <= 32; h1++) {
539 				struct route4_filter *f;
540 
541 				for (f = b->ht[h1]; f; f = f->next) {
542 					if (arg->count < arg->skip) {
543 						arg->count++;
544 						continue;
545 					}
546 					if (arg->fn(tp, (unsigned long)f, arg) < 0) {
547 						arg->stop = 1;
548 						return;
549 					}
550 					arg->count++;
551 				}
552 			}
553 		}
554 	}
555 }
556 
557 static int route4_dump(struct tcf_proto *tp, unsigned long fh,
558 		       struct sk_buff *skb, struct tcmsg *t)
559 {
560 	struct route4_filter *f = (struct route4_filter *)fh;
561 	unsigned char *b = skb_tail_pointer(skb);
562 	struct nlattr *nest;
563 	u32 id;
564 
565 	if (f == NULL)
566 		return skb->len;
567 
568 	t->tcm_handle = f->handle;
569 
570 	nest = nla_nest_start(skb, TCA_OPTIONS);
571 	if (nest == NULL)
572 		goto nla_put_failure;
573 
574 	if (!(f->handle & 0x8000)) {
575 		id = f->id & 0xFF;
576 		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
577 			goto nla_put_failure;
578 	}
579 	if (f->handle & 0x80000000) {
580 		if ((f->handle >> 16) != 0xFFFF &&
581 		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
582 			goto nla_put_failure;
583 	} else {
584 		id = f->id >> 16;
585 		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
586 			goto nla_put_failure;
587 	}
588 	if (f->res.classid &&
589 	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
590 		goto nla_put_failure;
591 
592 	if (tcf_exts_dump(skb, &f->exts, &route_ext_map) < 0)
593 		goto nla_put_failure;
594 
595 	nla_nest_end(skb, nest);
596 
597 	if (tcf_exts_dump_stats(skb, &f->exts, &route_ext_map) < 0)
598 		goto nla_put_failure;
599 
600 	return skb->len;
601 
602 nla_put_failure:
603 	nlmsg_trim(skb, b);
604 	return -1;
605 }
606 
607 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
608 	.kind		=	"route",
609 	.classify	=	route4_classify,
610 	.init		=	route4_init,
611 	.destroy	=	route4_destroy,
612 	.get		=	route4_get,
613 	.put		=	route4_put,
614 	.change		=	route4_change,
615 	.delete		=	route4_delete,
616 	.walk		=	route4_walk,
617 	.dump		=	route4_dump,
618 	.owner		=	THIS_MODULE,
619 };
620 
621 static int __init init_route4(void)
622 {
623 	return register_tcf_proto_ops(&cls_route4_ops);
624 }
625 
626 static void __exit exit_route4(void)
627 {
628 	unregister_tcf_proto_ops(&cls_route4_ops);
629 }
630 
631 module_init(init_route4)
632 module_exit(exit_route4)
633 MODULE_LICENSE("GPL");
634