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tty: serial: lpuart: avoid leaking struct tty_struct
[linux/fpc-iii.git] / net / sched / cls_tcindex.c
blob9ccc93f257db0966f5ea5206819cfdb7605c1e2a
1 /*
2 * net/sched/cls_tcindex.c Packet classifier for skb->tc_index
3 *
4 * Written 1998,1999 by Werner Almesberger, EPFL ICA
5 */
6
7 #include <linux/module.h>
8 #include <linux/types.h>
9 #include <linux/kernel.h>
10 #include <linux/skbuff.h>
11 #include <linux/errno.h>
12 #include <linux/slab.h>
13 #include <net/act_api.h>
14 #include <net/netlink.h>
15 #include <net/pkt_cls.h>
16 #include <net/sch_generic.h>
17
18 /*
19 * Passing parameters to the root seems to be done more awkwardly than really
20 * necessary. At least, u32 doesn't seem to use such dirty hacks. To be
21 * verified. FIXME.
22 */
23
24 #define PERFECT_HASH_THRESHOLD 64 /* use perfect hash if not bigger */
25 #define DEFAULT_HASH_SIZE 64 /* optimized for diffserv */
26
27
28 struct tcindex_filter_result {
29 struct tcf_exts exts;
30 struct tcf_result res;
31 struct rcu_work rwork;
32 };
33
34 struct tcindex_filter {
35 u16 key;
36 struct tcindex_filter_result result;
37 struct tcindex_filter __rcu *next;
38 struct rcu_work rwork;
39 };
40
41
42 struct tcindex_data {
43 struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
44 struct tcindex_filter __rcu **h; /* imperfect hash; */
45 struct tcf_proto *tp;
46 u16 mask; /* AND key with mask */
47 u32 shift; /* shift ANDed key to the right */
48 u32 hash; /* hash table size; 0 if undefined */
49 u32 alloc_hash; /* allocated size */
50 u32 fall_through; /* 0: only classify if explicit match */
51 struct rcu_head rcu;
52 };
53
54 static inline int tcindex_filter_is_set(struct tcindex_filter_result *r)
55 {
56 return tcf_exts_has_actions(&r->exts) || r->res.classid;
57 }
58
59 static struct tcindex_filter_result *tcindex_lookup(struct tcindex_data *p,
60 u16 key)
61 {
62 if (p->perfect) {
63 struct tcindex_filter_result *f = p->perfect + key;
64
65 return tcindex_filter_is_set(f) ? f : NULL;
66 } else if (p->h) {
67 struct tcindex_filter __rcu **fp;
68 struct tcindex_filter *f;
69
70 fp = &p->h[key % p->hash];
71 for (f = rcu_dereference_bh_rtnl(*fp);
72 f;
73 fp = &f->next, f = rcu_dereference_bh_rtnl(*fp))
74 if (f->key == key)
75 return &f->result;
76 }
77
78 return NULL;
79 }
80
81
82 static int tcindex_classify(struct sk_buff *skb, const struct tcf_proto *tp,
83 struct tcf_result *res)
84 {
85 struct tcindex_data *p = rcu_dereference_bh(tp->root);
86 struct tcindex_filter_result *f;
87 int key = (skb->tc_index & p->mask) >> p->shift;
88
89 pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n",
90 skb, tp, res, p);
91
92 f = tcindex_lookup(p, key);
93 if (!f) {
94 struct Qdisc *q = tcf_block_q(tp->chain->block);
95
96 if (!p->fall_through)
97 return -1;
98 res->classid = TC_H_MAKE(TC_H_MAJ(q->handle), key);
99 res->class = 0;
100 pr_debug("alg 0x%x\n", res->classid);
101 return 0;
102 }
103 *res = f->res;
104 pr_debug("map 0x%x\n", res->classid);
105
106 return tcf_exts_exec(skb, &f->exts, res);
107 }
108
109
110 static void *tcindex_get(struct tcf_proto *tp, u32 handle)
111 {
112 struct tcindex_data *p = rtnl_dereference(tp->root);
113 struct tcindex_filter_result *r;
114
115 pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle);
116 if (p->perfect && handle >= p->alloc_hash)
117 return NULL;
118 r = tcindex_lookup(p, handle);
119 return r && tcindex_filter_is_set(r) ? r : NULL;
120 }
121
122 static int tcindex_init(struct tcf_proto *tp)
123 {
124 struct tcindex_data *p;
125
126 pr_debug("tcindex_init(tp %p)\n", tp);
127 p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL);
128 if (!p)
129 return -ENOMEM;
130
131 p->mask = 0xffff;
132 p->hash = DEFAULT_HASH_SIZE;
133 p->fall_through = 1;
134
135 rcu_assign_pointer(tp->root, p);
136 return 0;
137 }
138
139 static void __tcindex_destroy_rexts(struct tcindex_filter_result *r)
140 {
141 tcf_exts_destroy(&r->exts);
142 tcf_exts_put_net(&r->exts);
143 }
144
145 static void tcindex_destroy_rexts_work(struct work_struct *work)
146 {
147 struct tcindex_filter_result *r;
148
149 r = container_of(to_rcu_work(work),
150 struct tcindex_filter_result,
151 rwork);
152 rtnl_lock();
153 __tcindex_destroy_rexts(r);
154 rtnl_unlock();
155 }
156
157 static void __tcindex_destroy_fexts(struct tcindex_filter *f)
158 {
159 tcf_exts_destroy(&f->result.exts);
160 tcf_exts_put_net(&f->result.exts);
161 kfree(f);
162 }
163
164 static void tcindex_destroy_fexts_work(struct work_struct *work)
165 {
166 struct tcindex_filter *f = container_of(to_rcu_work(work),
167 struct tcindex_filter,
168 rwork);
169
170 rtnl_lock();
171 __tcindex_destroy_fexts(f);
172 rtnl_unlock();
173 }
174
175 static int tcindex_delete(struct tcf_proto *tp, void *arg, bool *last,
176 struct netlink_ext_ack *extack)
177 {
178 struct tcindex_data *p = rtnl_dereference(tp->root);
179 struct tcindex_filter_result *r = arg;
180 struct tcindex_filter __rcu **walk;
181 struct tcindex_filter *f = NULL;
182
183 pr_debug("tcindex_delete(tp %p,arg %p),p %p\n", tp, arg, p);
184 if (p->perfect) {
185 if (!r->res.class)
186 return -ENOENT;
187 } else {
188 int i;
189
190 for (i = 0; i < p->hash; i++) {
191 walk = p->h + i;
192 for (f = rtnl_dereference(*walk); f;
193 walk = &f->next, f = rtnl_dereference(*walk)) {
194 if (&f->result == r)
195 goto found;
196 }
197 }
198 return -ENOENT;
199
200 found:
201 rcu_assign_pointer(*walk, rtnl_dereference(f->next));
202 }
203 tcf_unbind_filter(tp, &r->res);
204 /* all classifiers are required to call tcf_exts_destroy() after rcu
205 * grace period, since converted-to-rcu actions are relying on that
206 * in cleanup() callback
207 */
208 if (f) {
209 if (tcf_exts_get_net(&f->result.exts))
210 tcf_queue_work(&f->rwork, tcindex_destroy_fexts_work);
211 else
212 __tcindex_destroy_fexts(f);
213 } else {
214 if (tcf_exts_get_net(&r->exts))
215 tcf_queue_work(&r->rwork, tcindex_destroy_rexts_work);
216 else
217 __tcindex_destroy_rexts(r);
218 }
219
220 *last = false;
221 return 0;
222 }
223
224 static int tcindex_destroy_element(struct tcf_proto *tp,
225 void *arg, struct tcf_walker *walker)
226 {
227 bool last;
228
229 return tcindex_delete(tp, arg, &last, NULL);
230 }
231
232 static void __tcindex_destroy(struct rcu_head *head)
233 {
234 struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
235
236 kfree(p->perfect);
237 kfree(p->h);
238 kfree(p);
239 }
240
241 static inline int
242 valid_perfect_hash(struct tcindex_data *p)
243 {
244 return p->hash > (p->mask >> p->shift);
245 }
246
247 static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
248 [TCA_TCINDEX_HASH] = { .type = NLA_U32 },
249 [TCA_TCINDEX_MASK] = { .type = NLA_U16 },
250 [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
251 [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
252 [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
253 };
254
255 static int tcindex_filter_result_init(struct tcindex_filter_result *r)
256 {
257 memset(r, 0, sizeof(*r));
258 return tcf_exts_init(&r->exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
259 }
260
261 static void __tcindex_partial_destroy(struct rcu_head *head)
262 {
263 struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
264
265 kfree(p->perfect);
266 kfree(p);
267 }
268
269 static void tcindex_free_perfect_hash(struct tcindex_data *cp)
270 {
271 int i;
272
273 for (i = 0; i < cp->hash; i++)
274 tcf_exts_destroy(&cp->perfect[i].exts);
275 kfree(cp->perfect);
276 }
277
278 static int tcindex_alloc_perfect_hash(struct tcindex_data *cp)
279 {
280 int i, err = 0;
281
282 cp->perfect = kcalloc(cp->hash, sizeof(struct tcindex_filter_result),
283 GFP_KERNEL);
284 if (!cp->perfect)
285 return -ENOMEM;
286
287 for (i = 0; i < cp->hash; i++) {
288 err = tcf_exts_init(&cp->perfect[i].exts,
289 TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
290 if (err < 0)
291 goto errout;
292 }
293
294 return 0;
295
296 errout:
297 tcindex_free_perfect_hash(cp);
298 return err;
299 }
300
301 static int
302 tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
303 u32 handle, struct tcindex_data *p,
304 struct tcindex_filter_result *r, struct nlattr **tb,
305 struct nlattr *est, bool ovr, struct netlink_ext_ack *extack)
306 {
307 struct tcindex_filter_result new_filter_result, *old_r = r;
308 struct tcindex_filter_result cr;
309 struct tcindex_data *cp = NULL, *oldp;
310 struct tcindex_filter *f = NULL; /* make gcc behave */
311 int err, balloc = 0;
312 struct tcf_exts e;
313
314 err = tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
315 if (err < 0)
316 return err;
317 err = tcf_exts_validate(net, tp, tb, est, &e, ovr, extack);
318 if (err < 0)
319 goto errout;
320
321 err = -ENOMEM;
322 /* tcindex_data attributes must look atomic to classifier/lookup so
323 * allocate new tcindex data and RCU assign it onto root. Keeping
324 * perfect hash and hash pointers from old data.
325 */
326 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
327 if (!cp)
328 goto errout;
329
330 cp->mask = p->mask;
331 cp->shift = p->shift;
332 cp->hash = p->hash;
333 cp->alloc_hash = p->alloc_hash;
334 cp->fall_through = p->fall_through;
335 cp->tp = tp;
336
337 if (p->perfect) {
338 int i;
339
340 if (tcindex_alloc_perfect_hash(cp) < 0)
341 goto errout;
342 for (i = 0; i < cp->hash; i++)
343 cp->perfect[i].res = p->perfect[i].res;
344 balloc = 1;
345 }
346 cp->h = p->h;
347
348 err = tcindex_filter_result_init(&new_filter_result);
349 if (err < 0)
350 goto errout1;
351 err = tcindex_filter_result_init(&cr);
352 if (err < 0)
353 goto errout1;
354 if (old_r)
355 cr.res = r->res;
356
357 if (tb[TCA_TCINDEX_HASH])
358 cp->hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
359
360 if (tb[TCA_TCINDEX_MASK])
361 cp->mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
362
363 if (tb[TCA_TCINDEX_SHIFT])
364 cp->shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
365
366 err = -EBUSY;
367
368 /* Hash already allocated, make sure that we still meet the
369 * requirements for the allocated hash.
370 */
371 if (cp->perfect) {
372 if (!valid_perfect_hash(cp) ||
373 cp->hash > cp->alloc_hash)
374 goto errout_alloc;
375 } else if (cp->h && cp->hash != cp->alloc_hash) {
376 goto errout_alloc;
377 }
378
379 err = -EINVAL;
380 if (tb[TCA_TCINDEX_FALL_THROUGH])
381 cp->fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
382
383 if (!cp->hash) {
384 /* Hash not specified, use perfect hash if the upper limit
385 * of the hashing index is below the threshold.
386 */
387 if ((cp->mask >> cp->shift) < PERFECT_HASH_THRESHOLD)
388 cp->hash = (cp->mask >> cp->shift) + 1;
389 else
390 cp->hash = DEFAULT_HASH_SIZE;
391 }
392
393 if (!cp->perfect && !cp->h)
394 cp->alloc_hash = cp->hash;
395
396 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
397 * but then, we'd fail handles that may become valid after some future
398 * mask change. While this is extremely unlikely to ever matter,
399 * the check below is safer (and also more backwards-compatible).
400 */
401 if (cp->perfect || valid_perfect_hash(cp))
402 if (handle >= cp->alloc_hash)
403 goto errout_alloc;
404
405
406 err = -ENOMEM;
407 if (!cp->perfect && !cp->h) {
408 if (valid_perfect_hash(cp)) {
409 if (tcindex_alloc_perfect_hash(cp) < 0)
410 goto errout_alloc;
411 balloc = 1;
412 } else {
413 struct tcindex_filter __rcu **hash;
414
415 hash = kcalloc(cp->hash,
416 sizeof(struct tcindex_filter *),
417 GFP_KERNEL);
418
419 if (!hash)
420 goto errout_alloc;
421
422 cp->h = hash;
423 balloc = 2;
424 }
425 }
426
427 if (cp->perfect)
428 r = cp->perfect + handle;
429 else
430 r = tcindex_lookup(cp, handle) ? : &new_filter_result;
431
432 if (r == &new_filter_result) {
433 f = kzalloc(sizeof(*f), GFP_KERNEL);
434 if (!f)
435 goto errout_alloc;
436 f->key = handle;
437 f->next = NULL;
438 err = tcindex_filter_result_init(&f->result);
439 if (err < 0) {
440 kfree(f);
441 goto errout_alloc;
442 }
443 }
444
445 if (tb[TCA_TCINDEX_CLASSID]) {
446 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
447 tcf_bind_filter(tp, &cr.res, base);
448 }
449
450 if (old_r && old_r != r) {
451 err = tcindex_filter_result_init(old_r);
452 if (err < 0) {
453 kfree(f);
454 goto errout_alloc;
455 }
456 }
457
458 oldp = p;
459 r->res = cr.res;
460 tcf_exts_change(&r->exts, &e);
461
462 rcu_assign_pointer(tp->root, cp);
463
464 if (r == &new_filter_result) {
465 struct tcindex_filter *nfp;
466 struct tcindex_filter __rcu **fp;
467
468 f->result.res = r->res;
469 tcf_exts_change(&f->result.exts, &r->exts);
470
471 fp = cp->h + (handle % cp->hash);
472 for (nfp = rtnl_dereference(*fp);
473 nfp;
474 fp = &nfp->next, nfp = rtnl_dereference(*fp))
475 ; /* nothing */
476
477 rcu_assign_pointer(*fp, f);
478 }
479
480 if (oldp)
481 call_rcu(&oldp->rcu, __tcindex_partial_destroy);
482 return 0;
483
484 errout_alloc:
485 if (balloc == 1)
486 tcindex_free_perfect_hash(cp);
487 else if (balloc == 2)
488 kfree(cp->h);
489 errout1:
490 tcf_exts_destroy(&cr.exts);
491 tcf_exts_destroy(&new_filter_result.exts);
492 errout:
493 kfree(cp);
494 tcf_exts_destroy(&e);
495 return err;
496 }
497
498 static int
499 tcindex_change(struct net *net, struct sk_buff *in_skb,
500 struct tcf_proto *tp, unsigned long base, u32 handle,
501 struct nlattr **tca, void **arg, bool ovr,
502 struct netlink_ext_ack *extack)
503 {
504 struct nlattr *opt = tca[TCA_OPTIONS];
505 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
506 struct tcindex_data *p = rtnl_dereference(tp->root);
507 struct tcindex_filter_result *r = *arg;
508 int err;
509
510 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
511 "p %p,r %p,*arg %p\n",
512 tp, handle, tca, arg, opt, p, r, arg ? *arg : NULL);
513
514 if (!opt)
515 return 0;
516
517 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy, NULL);
518 if (err < 0)
519 return err;
520
521 return tcindex_set_parms(net, tp, base, handle, p, r, tb,
522 tca[TCA_RATE], ovr, extack);
523 }
524
525 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
526 {
527 struct tcindex_data *p = rtnl_dereference(tp->root);
528 struct tcindex_filter *f, *next;
529 int i;
530
531 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
532 if (p->perfect) {
533 for (i = 0; i < p->hash; i++) {
534 if (!p->perfect[i].res.class)
535 continue;
536 if (walker->count >= walker->skip) {
537 if (walker->fn(tp, p->perfect + i, walker) < 0) {
538 walker->stop = 1;
539 return;
540 }
541 }
542 walker->count++;
543 }
544 }
545 if (!p->h)
546 return;
547 for (i = 0; i < p->hash; i++) {
548 for (f = rtnl_dereference(p->h[i]); f; f = next) {
549 next = rtnl_dereference(f->next);
550 if (walker->count >= walker->skip) {
551 if (walker->fn(tp, &f->result, walker) < 0) {
552 walker->stop = 1;
553 return;
554 }
555 }
556 walker->count++;
557 }
558 }
559 }
560
561 static void tcindex_destroy(struct tcf_proto *tp,
562 struct netlink_ext_ack *extack)
563 {
564 struct tcindex_data *p = rtnl_dereference(tp->root);
565 struct tcf_walker walker;
566
567 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
568 walker.count = 0;
569 walker.skip = 0;
570 walker.fn = tcindex_destroy_element;
571 tcindex_walk(tp, &walker);
572
573 call_rcu(&p->rcu, __tcindex_destroy);
574 }
575
576
577 static int tcindex_dump(struct net *net, struct tcf_proto *tp, void *fh,
578 struct sk_buff *skb, struct tcmsg *t)
579 {
580 struct tcindex_data *p = rtnl_dereference(tp->root);
581 struct tcindex_filter_result *r = fh;
582 struct nlattr *nest;
583
584 pr_debug("tcindex_dump(tp %p,fh %p,skb %p,t %p),p %p,r %p\n",
585 tp, fh, skb, t, p, r);
586 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
587
588 nest = nla_nest_start(skb, TCA_OPTIONS);
589 if (nest == NULL)
590 goto nla_put_failure;
591
592 if (!fh) {
593 t->tcm_handle = ~0; /* whatever ... */
594 if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) ||
595 nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) ||
596 nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) ||
597 nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
598 goto nla_put_failure;
599 nla_nest_end(skb, nest);
600 } else {
601 if (p->perfect) {
602 t->tcm_handle = r - p->perfect;
603 } else {
604 struct tcindex_filter *f;
605 struct tcindex_filter __rcu **fp;
606 int i;
607
608 t->tcm_handle = 0;
609 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
610 fp = &p->h[i];
611 for (f = rtnl_dereference(*fp);
612 !t->tcm_handle && f;
613 fp = &f->next, f = rtnl_dereference(*fp)) {
614 if (&f->result == r)
615 t->tcm_handle = f->key;
616 }
617 }
618 }
619 pr_debug("handle = %d\n", t->tcm_handle);
620 if (r->res.class &&
621 nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
622 goto nla_put_failure;
623
624 if (tcf_exts_dump(skb, &r->exts) < 0)
625 goto nla_put_failure;
626 nla_nest_end(skb, nest);
627
628 if (tcf_exts_dump_stats(skb, &r->exts) < 0)
629 goto nla_put_failure;
630 }
631
632 return skb->len;
633
634 nla_put_failure:
635 nla_nest_cancel(skb, nest);
636 return -1;
637 }
638
639 static void tcindex_bind_class(void *fh, u32 classid, unsigned long cl)
640 {
641 struct tcindex_filter_result *r = fh;
642
643 if (r && r->res.classid == classid)
644 r->res.class = cl;
645 }
646
647 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
648 .kind = "tcindex",
649 .classify = tcindex_classify,
650 .init = tcindex_init,
651 .destroy = tcindex_destroy,
652 .get = tcindex_get,
653 .change = tcindex_change,
654 .delete = tcindex_delete,
655 .walk = tcindex_walk,
656 .dump = tcindex_dump,
657 .bind_class = tcindex_bind_class,
658 .owner = THIS_MODULE,
659 };
660
661 static int __init init_tcindex(void)
662 {
663 return register_tcf_proto_ops(&cls_tcindex_ops);
664 }
665
666 static void __exit exit_tcindex(void)
667 {
668 unregister_tcf_proto_ops(&cls_tcindex_ops);
669 }
670
671 module_init(init_tcindex)
672 module_exit(exit_tcindex)
673 MODULE_LICENSE("GPL");
Linux with added FPC-III support