xref: /openbmc/linux/net/sched/cls_route.c (revision db181ce0) 
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 inline int route4_fastmap_hash(u32 id, int iif)
63 {
64 	return id & 0xF;
65 }
66 
67 static void
68 route4_reset_fastmap(struct Qdisc *q, struct route4_head *head, u32 id)
69 {
70 	spinlock_t *root_lock = qdisc_root_sleeping_lock(q);
71 
72 	spin_lock_bh(root_lock);
73 	memset(head->fastmap, 0, sizeof(head->fastmap));
74 	spin_unlock_bh(root_lock);
75 }
76 
77 static void
78 route4_set_fastmap(struct route4_head *head, u32 id, int iif,
79 		   struct route4_filter *f)
80 {
81 	int h = route4_fastmap_hash(id, iif);
82 
83 	head->fastmap[h].id = id;
84 	head->fastmap[h].iif = iif;
85 	head->fastmap[h].filter = f;
86 }
87 
88 static inline int route4_hash_to(u32 id)
89 {
90 	return id & 0xFF;
91 }
92 
93 static inline int route4_hash_from(u32 id)
94 {
95 	return (id >> 16) & 0xF;
96 }
97 
98 static inline int route4_hash_iif(int iif)
99 {
100 	return 16 + ((iif >> 16) & 0xF);
101 }
102 
103 static inline int route4_hash_wild(void)
104 {
105 	return 32;
106 }
107 
108 #define ROUTE4_APPLY_RESULT()					\
109 {								\
110 	*res = f->res;						\
111 	if (tcf_exts_is_available(&f->exts)) {			\
112 		int r = tcf_exts_exec(skb, &f->exts, res);	\
113 		if (r < 0) {					\
114 			dont_cache = 1;				\
115 			continue;				\
116 		}						\
117 		return r;					\
118 	} else if (!dont_cache)					\
119 		route4_set_fastmap(head, id, iif, f);		\
120 	return 0;						\
121 }
122 
123 static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
124 			   struct tcf_result *res)
125 {
126 	struct route4_head *head = tp->root;
127 	struct dst_entry *dst;
128 	struct route4_bucket *b;
129 	struct route4_filter *f;
130 	u32 id, h;
131 	int iif, dont_cache = 0;
132 
133 	dst = skb_dst(skb);
134 	if (!dst)
135 		goto failure;
136 
137 	id = dst->tclassid;
138 	if (head == NULL)
139 		goto old_method;
140 
141 	iif = inet_iif(skb);
142 
143 	h = route4_fastmap_hash(id, iif);
144 	if (id == head->fastmap[h].id &&
145 	    iif == head->fastmap[h].iif &&
146 	    (f = head->fastmap[h].filter) != NULL) {
147 		if (f == ROUTE4_FAILURE)
148 			goto failure;
149 
150 		*res = f->res;
151 		return 0;
152 	}
153 
154 	h = route4_hash_to(id);
155 
156 restart:
157 	b = head->table[h];
158 	if (b) {
159 		for (f = b->ht[route4_hash_from(id)]; f; f = f->next)
160 			if (f->id == id)
161 				ROUTE4_APPLY_RESULT();
162 
163 		for (f = b->ht[route4_hash_iif(iif)]; f; f = f->next)
164 			if (f->iif == iif)
165 				ROUTE4_APPLY_RESULT();
166 
167 		for (f = b->ht[route4_hash_wild()]; f; f = f->next)
168 			ROUTE4_APPLY_RESULT();
169 
170 	}
171 	if (h < 256) {
172 		h = 256;
173 		id &= ~0xFFFF;
174 		goto restart;
175 	}
176 
177 	if (!dont_cache)
178 		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
179 failure:
180 	return -1;
181 
182 old_method:
183 	if (id && (TC_H_MAJ(id) == 0 ||
184 		   !(TC_H_MAJ(id^tp->q->handle)))) {
185 		res->classid = id;
186 		res->class = 0;
187 		return 0;
188 	}
189 	return -1;
190 }
191 
192 static inline u32 to_hash(u32 id)
193 {
194 	u32 h = id & 0xFF;
195 
196 	if (id & 0x8000)
197 		h += 256;
198 	return h;
199 }
200 
201 static inline u32 from_hash(u32 id)
202 {
203 	id &= 0xFFFF;
204 	if (id == 0xFFFF)
205 		return 32;
206 	if (!(id & 0x8000)) {
207 		if (id > 255)
208 			return 256;
209 		return id & 0xF;
210 	}
211 	return 16 + (id & 0xF);
212 }
213 
214 static unsigned long route4_get(struct tcf_proto *tp, u32 handle)
215 {
216 	struct route4_head *head = tp->root;
217 	struct route4_bucket *b;
218 	struct route4_filter *f;
219 	unsigned int h1, h2;
220 
221 	if (!head)
222 		return 0;
223 
224 	h1 = to_hash(handle);
225 	if (h1 > 256)
226 		return 0;
227 
228 	h2 = from_hash(handle >> 16);
229 	if (h2 > 32)
230 		return 0;
231 
232 	b = head->table[h1];
233 	if (b) {
234 		for (f = b->ht[h2]; f; f = f->next)
235 			if (f->handle == handle)
236 				return (unsigned long)f;
237 	}
238 	return 0;
239 }
240 
241 static void route4_put(struct tcf_proto *tp, unsigned long f)
242 {
243 }
244 
245 static int route4_init(struct tcf_proto *tp)
246 {
247 	return 0;
248 }
249 
250 static void
251 route4_delete_filter(struct tcf_proto *tp, struct route4_filter *f)
252 {
253 	tcf_unbind_filter(tp, &f->res);
254 	tcf_exts_destroy(tp, &f->exts);
255 	kfree(f);
256 }
257 
258 static void route4_destroy(struct tcf_proto *tp)
259 {
260 	struct route4_head *head = tp->root;
261 	int h1, h2;
262 
263 	if (head == NULL)
264 		return;
265 
266 	for (h1 = 0; h1 <= 256; h1++) {
267 		struct route4_bucket *b;
268 
269 		b = head->table[h1];
270 		if (b) {
271 			for (h2 = 0; h2 <= 32; h2++) {
272 				struct route4_filter *f;
273 
274 				while ((f = b->ht[h2]) != NULL) {
275 					b->ht[h2] = f->next;
276 					route4_delete_filter(tp, f);
277 				}
278 			}
279 			kfree(b);
280 		}
281 	}
282 	kfree(head);
283 }
284 
285 static int route4_delete(struct tcf_proto *tp, unsigned long arg)
286 {
287 	struct route4_head *head = tp->root;
288 	struct route4_filter **fp, *f = (struct route4_filter *)arg;
289 	unsigned int h = 0;
290 	struct route4_bucket *b;
291 	int i;
292 
293 	if (!head || !f)
294 		return -EINVAL;
295 
296 	h = f->handle;
297 	b = f->bkt;
298 
299 	for (fp = &b->ht[from_hash(h >> 16)]; *fp; fp = &(*fp)->next) {
300 		if (*fp == f) {
301 			tcf_tree_lock(tp);
302 			*fp = f->next;
303 			tcf_tree_unlock(tp);
304 
305 			route4_reset_fastmap(tp->q, head, f->id);
306 			route4_delete_filter(tp, f);
307 
308 			/* Strip tree */
309 
310 			for (i = 0; i <= 32; i++)
311 				if (b->ht[i])
312 					return 0;
313 
314 			/* OK, session has no flows */
315 			tcf_tree_lock(tp);
316 			head->table[to_hash(h)] = NULL;
317 			tcf_tree_unlock(tp);
318 
319 			kfree(b);
320 			return 0;
321 		}
322 	}
323 	return 0;
324 }
325 
326 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
327 	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
328 	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
329 	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
330 	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
331 };
332 
333 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
334 			    unsigned long base, struct route4_filter *f,
335 			    u32 handle, struct route4_head *head,
336 			    struct nlattr **tb, struct nlattr *est, int new,
337 			    bool ovr)
338 {
339 	int err;
340 	u32 id = 0, to = 0, nhandle = 0x8000;
341 	struct route4_filter *fp;
342 	unsigned int h1;
343 	struct route4_bucket *b;
344 	struct tcf_exts e;
345 
346 	tcf_exts_init(&e, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
347 	err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
348 	if (err < 0)
349 		return err;
350 
351 	err = -EINVAL;
352 	if (tb[TCA_ROUTE4_TO]) {
353 		if (new && handle & 0x8000)
354 			goto errout;
355 		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
356 		if (to > 0xFF)
357 			goto errout;
358 		nhandle = to;
359 	}
360 
361 	if (tb[TCA_ROUTE4_FROM]) {
362 		if (tb[TCA_ROUTE4_IIF])
363 			goto errout;
364 		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
365 		if (id > 0xFF)
366 			goto errout;
367 		nhandle |= id << 16;
368 	} else if (tb[TCA_ROUTE4_IIF]) {
369 		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
370 		if (id > 0x7FFF)
371 			goto errout;
372 		nhandle |= (id | 0x8000) << 16;
373 	} else
374 		nhandle |= 0xFFFF << 16;
375 
376 	if (handle && new) {
377 		nhandle |= handle & 0x7F00;
378 		if (nhandle != handle)
379 			goto errout;
380 	}
381 
382 	h1 = to_hash(nhandle);
383 	b = head->table[h1];
384 	if (!b) {
385 		err = -ENOBUFS;
386 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
387 		if (b == NULL)
388 			goto errout;
389 
390 		tcf_tree_lock(tp);
391 		head->table[h1] = b;
392 		tcf_tree_unlock(tp);
393 	} else {
394 		unsigned int h2 = from_hash(nhandle >> 16);
395 
396 		err = -EEXIST;
397 		for (fp = b->ht[h2]; fp; fp = fp->next)
398 			if (fp->handle == f->handle)
399 				goto errout;
400 	}
401 
402 	tcf_tree_lock(tp);
403 	if (tb[TCA_ROUTE4_TO])
404 		f->id = to;
405 
406 	if (tb[TCA_ROUTE4_FROM])
407 		f->id = to | id<<16;
408 	else if (tb[TCA_ROUTE4_IIF])
409 		f->iif = id;
410 
411 	f->handle = nhandle;
412 	f->bkt = b;
413 	tcf_tree_unlock(tp);
414 
415 	if (tb[TCA_ROUTE4_CLASSID]) {
416 		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
417 		tcf_bind_filter(tp, &f->res, base);
418 	}
419 
420 	tcf_exts_change(tp, &f->exts, &e);
421 
422 	return 0;
423 errout:
424 	tcf_exts_destroy(tp, &e);
425 	return err;
426 }
427 
428 static int route4_change(struct net *net, struct sk_buff *in_skb,
429 		       struct tcf_proto *tp, unsigned long base,
430 		       u32 handle,
431 		       struct nlattr **tca,
432 		       unsigned long *arg, bool ovr)
433 {
434 	struct route4_head *head = tp->root;
435 	struct route4_filter *f, *f1, **fp;
436 	struct route4_bucket *b;
437 	struct nlattr *opt = tca[TCA_OPTIONS];
438 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
439 	unsigned int h, th;
440 	u32 old_handle = 0;
441 	int err;
442 
443 	if (opt == NULL)
444 		return handle ? -EINVAL : 0;
445 
446 	err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy);
447 	if (err < 0)
448 		return err;
449 
450 	f = (struct route4_filter *)*arg;
451 	if (f) {
452 		if (f->handle != handle && handle)
453 			return -EINVAL;
454 
455 		if (f->bkt)
456 			old_handle = f->handle;
457 
458 		err = route4_set_parms(net, tp, base, f, handle, head, tb,
459 			tca[TCA_RATE], 0, ovr);
460 		if (err < 0)
461 			return err;
462 
463 		goto reinsert;
464 	}
465 
466 	err = -ENOBUFS;
467 	if (head == NULL) {
468 		head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
469 		if (head == NULL)
470 			goto errout;
471 
472 		tcf_tree_lock(tp);
473 		tp->root = head;
474 		tcf_tree_unlock(tp);
475 	}
476 
477 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
478 	if (f == NULL)
479 		goto errout;
480 
481 	tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
482 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
483 		tca[TCA_RATE], 1, ovr);
484 	if (err < 0)
485 		goto errout;
486 
487 reinsert:
488 	h = from_hash(f->handle >> 16);
489 	for (fp = &f->bkt->ht[h]; (f1 = *fp) != NULL; fp = &f1->next)
490 		if (f->handle < f1->handle)
491 			break;
492 
493 	f->next = f1;
494 	tcf_tree_lock(tp);
495 	*fp = f;
496 
497 	if (old_handle && f->handle != old_handle) {
498 		th = to_hash(old_handle);
499 		h = from_hash(old_handle >> 16);
500 		b = head->table[th];
501 		if (b) {
502 			for (fp = &b->ht[h]; *fp; fp = &(*fp)->next) {
503 				if (*fp == f) {
504 					*fp = f->next;
505 					break;
506 				}
507 			}
508 		}
509 	}
510 	tcf_tree_unlock(tp);
511 
512 	route4_reset_fastmap(tp->q, head, f->id);
513 	*arg = (unsigned long)f;
514 	return 0;
515 
516 errout:
517 	kfree(f);
518 	return err;
519 }
520 
521 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
522 {
523 	struct route4_head *head = tp->root;
524 	unsigned int h, h1;
525 
526 	if (head == NULL)
527 		arg->stop = 1;
528 
529 	if (arg->stop)
530 		return;
531 
532 	for (h = 0; h <= 256; h++) {
533 		struct route4_bucket *b = head->table[h];
534 
535 		if (b) {
536 			for (h1 = 0; h1 <= 32; h1++) {
537 				struct route4_filter *f;
538 
539 				for (f = b->ht[h1]; f; f = f->next) {
540 					if (arg->count < arg->skip) {
541 						arg->count++;
542 						continue;
543 					}
544 					if (arg->fn(tp, (unsigned long)f, arg) < 0) {
545 						arg->stop = 1;
546 						return;
547 					}
548 					arg->count++;
549 				}
550 			}
551 		}
552 	}
553 }
554 
555 static int route4_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
556 		       struct sk_buff *skb, struct tcmsg *t)
557 {
558 	struct route4_filter *f = (struct route4_filter *)fh;
559 	unsigned char *b = skb_tail_pointer(skb);
560 	struct nlattr *nest;
561 	u32 id;
562 
563 	if (f == NULL)
564 		return skb->len;
565 
566 	t->tcm_handle = f->handle;
567 
568 	nest = nla_nest_start(skb, TCA_OPTIONS);
569 	if (nest == NULL)
570 		goto nla_put_failure;
571 
572 	if (!(f->handle & 0x8000)) {
573 		id = f->id & 0xFF;
574 		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
575 			goto nla_put_failure;
576 	}
577 	if (f->handle & 0x80000000) {
578 		if ((f->handle >> 16) != 0xFFFF &&
579 		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
580 			goto nla_put_failure;
581 	} else {
582 		id = f->id >> 16;
583 		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
584 			goto nla_put_failure;
585 	}
586 	if (f->res.classid &&
587 	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
588 		goto nla_put_failure;
589 
590 	if (tcf_exts_dump(skb, &f->exts) < 0)
591 		goto nla_put_failure;
592 
593 	nla_nest_end(skb, nest);
594 
595 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
596 		goto nla_put_failure;
597 
598 	return skb->len;
599 
600 nla_put_failure:
601 	nlmsg_trim(skb, b);
602 	return -1;
603 }
604 
605 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
606 	.kind		=	"route",
607 	.classify	=	route4_classify,
608 	.init		=	route4_init,
609 	.destroy	=	route4_destroy,
610 	.get		=	route4_get,
611 	.put		=	route4_put,
612 	.change		=	route4_change,
613 	.delete		=	route4_delete,
614 	.walk		=	route4_walk,
615 	.dump		=	route4_dump,
616 	.owner		=	THIS_MODULE,
617 };
618 
619 static int __init init_route4(void)
620 {
621 	return register_tcf_proto_ops(&cls_route4_ops);
622 }
623 
624 static void __exit exit_route4(void)
625 {
626 	unregister_tcf_proto_ops(&cls_route4_ops);
627 }
628 
629 module_init(init_route4)
630 module_exit(exit_route4)
631 MODULE_LICENSE("GPL");
632