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ARC: [*defconfig] Reenable soft lock-up detector
[linux/fpc-iii.git] / net / sched / cls_tcindex.c
blob14a7e08b2fa9e2f8a3551f6dbc1fb38f1e8df579
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
17 /*
18 * Passing parameters to the root seems to be done more awkwardly than really
19 * necessary. At least, u32 doesn't seem to use such dirty hacks. To be
20 * verified. FIXME.
21 */
22
23 #define PERFECT_HASH_THRESHOLD 64 /* use perfect hash if not bigger */
24 #define DEFAULT_HASH_SIZE 64 /* optimized for diffserv */
25
26
27 struct tcindex_filter_result {
28 struct tcf_exts exts;
29 struct tcf_result res;
30 struct rcu_head rcu;
31 };
32
33 struct tcindex_filter {
34 u16 key;
35 struct tcindex_filter_result result;
36 struct tcindex_filter __rcu *next;
37 struct rcu_head rcu;
38 };
39
40
41 struct tcindex_data {
42 struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
43 struct tcindex_filter __rcu **h; /* imperfect hash; */
44 struct tcf_proto *tp;
45 u16 mask; /* AND key with mask */
46 u32 shift; /* shift ANDed key to the right */
47 u32 hash; /* hash table size; 0 if undefined */
48 u32 alloc_hash; /* allocated size */
49 u32 fall_through; /* 0: only classify if explicit match */
50 struct rcu_head rcu;
51 };
52
53 static inline int tcindex_filter_is_set(struct tcindex_filter_result *r)
54 {
55 return tcf_exts_has_actions(&r->exts) || r->res.classid;
56 }
57
58 static struct tcindex_filter_result *tcindex_lookup(struct tcindex_data *p,
59 u16 key)
60 {
61 if (p->perfect) {
62 struct tcindex_filter_result *f = p->perfect + key;
63
64 return tcindex_filter_is_set(f) ? f : NULL;
65 } else if (p->h) {
66 struct tcindex_filter __rcu **fp;
67 struct tcindex_filter *f;
68
69 fp = &p->h[key % p->hash];
70 for (f = rcu_dereference_bh_rtnl(*fp);
71 f;
72 fp = &f->next, f = rcu_dereference_bh_rtnl(*fp))
73 if (f->key == key)
74 return &f->result;
75 }
76
77 return NULL;
78 }
79
80
81 static int tcindex_classify(struct sk_buff *skb, const struct tcf_proto *tp,
82 struct tcf_result *res)
83 {
84 struct tcindex_data *p = rcu_dereference_bh(tp->root);
85 struct tcindex_filter_result *f;
86 int key = (skb->tc_index & p->mask) >> p->shift;
87
88 pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n",
89 skb, tp, res, p);
90
91 f = tcindex_lookup(p, key);
92 if (!f) {
93 if (!p->fall_through)
94 return -1;
95 res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key);
96 res->class = 0;
97 pr_debug("alg 0x%x\n", res->classid);
98 return 0;
99 }
100 *res = f->res;
101 pr_debug("map 0x%x\n", res->classid);
102
103 return tcf_exts_exec(skb, &f->exts, res);
104 }
105
106
107 static void *tcindex_get(struct tcf_proto *tp, u32 handle)
108 {
109 struct tcindex_data *p = rtnl_dereference(tp->root);
110 struct tcindex_filter_result *r;
111
112 pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle);
113 if (p->perfect && handle >= p->alloc_hash)
114 return NULL;
115 r = tcindex_lookup(p, handle);
116 return r && tcindex_filter_is_set(r) ? r : NULL;
117 }
118
119 static int tcindex_init(struct tcf_proto *tp)
120 {
121 struct tcindex_data *p;
122
123 pr_debug("tcindex_init(tp %p)\n", tp);
124 p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL);
125 if (!p)
126 return -ENOMEM;
127
128 p->mask = 0xffff;
129 p->hash = DEFAULT_HASH_SIZE;
130 p->fall_through = 1;
131
132 rcu_assign_pointer(tp->root, p);
133 return 0;
134 }
135
136 static void tcindex_destroy_rexts(struct rcu_head *head)
137 {
138 struct tcindex_filter_result *r;
139
140 r = container_of(head, struct tcindex_filter_result, rcu);
141 tcf_exts_destroy(&r->exts);
142 }
143
144 static void tcindex_destroy_fexts(struct rcu_head *head)
145 {
146 struct tcindex_filter *f = container_of(head, struct tcindex_filter,
147 rcu);
148
149 tcf_exts_destroy(&f->result.exts);
150 kfree(f);
151 }
152
153 static int tcindex_delete(struct tcf_proto *tp, void *arg, bool *last)
154 {
155 struct tcindex_data *p = rtnl_dereference(tp->root);
156 struct tcindex_filter_result *r = arg;
157 struct tcindex_filter __rcu **walk;
158 struct tcindex_filter *f = NULL;
159
160 pr_debug("tcindex_delete(tp %p,arg %p),p %p\n", tp, arg, p);
161 if (p->perfect) {
162 if (!r->res.class)
163 return -ENOENT;
164 } else {
165 int i;
166
167 for (i = 0; i < p->hash; i++) {
168 walk = p->h + i;
169 for (f = rtnl_dereference(*walk); f;
170 walk = &f->next, f = rtnl_dereference(*walk)) {
171 if (&f->result == r)
172 goto found;
173 }
174 }
175 return -ENOENT;
176
177 found:
178 rcu_assign_pointer(*walk, rtnl_dereference(f->next));
179 }
180 tcf_unbind_filter(tp, &r->res);
181 /* all classifiers are required to call tcf_exts_destroy() after rcu
182 * grace period, since converted-to-rcu actions are relying on that
183 * in cleanup() callback
184 */
185 if (f)
186 call_rcu(&f->rcu, tcindex_destroy_fexts);
187 else
188 call_rcu(&r->rcu, tcindex_destroy_rexts);
189
190 *last = false;
191 return 0;
192 }
193
194 static int tcindex_destroy_element(struct tcf_proto *tp,
195 void *arg, struct tcf_walker *walker)
196 {
197 bool last;
198
199 return tcindex_delete(tp, arg, &last);
200 }
201
202 static void __tcindex_destroy(struct rcu_head *head)
203 {
204 struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
205
206 kfree(p->perfect);
207 kfree(p->h);
208 kfree(p);
209 }
210
211 static inline int
212 valid_perfect_hash(struct tcindex_data *p)
213 {
214 return p->hash > (p->mask >> p->shift);
215 }
216
217 static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
218 [TCA_TCINDEX_HASH] = { .type = NLA_U32 },
219 [TCA_TCINDEX_MASK] = { .type = NLA_U16 },
220 [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
221 [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
222 [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
223 };
224
225 static int tcindex_filter_result_init(struct tcindex_filter_result *r)
226 {
227 memset(r, 0, sizeof(*r));
228 return tcf_exts_init(&r->exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
229 }
230
231 static void __tcindex_partial_destroy(struct rcu_head *head)
232 {
233 struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
234
235 kfree(p->perfect);
236 kfree(p);
237 }
238
239 static void tcindex_free_perfect_hash(struct tcindex_data *cp)
240 {
241 int i;
242
243 for (i = 0; i < cp->hash; i++)
244 tcf_exts_destroy(&cp->perfect[i].exts);
245 kfree(cp->perfect);
246 }
247
248 static int tcindex_alloc_perfect_hash(struct tcindex_data *cp)
249 {
250 int i, err = 0;
251
252 cp->perfect = kcalloc(cp->hash, sizeof(struct tcindex_filter_result),
253 GFP_KERNEL);
254 if (!cp->perfect)
255 return -ENOMEM;
256
257 for (i = 0; i < cp->hash; i++) {
258 err = tcf_exts_init(&cp->perfect[i].exts,
259 TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
260 if (err < 0)
261 goto errout;
262 }
263
264 return 0;
265
266 errout:
267 tcindex_free_perfect_hash(cp);
268 return err;
269 }
270
271 static int
272 tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
273 u32 handle, struct tcindex_data *p,
274 struct tcindex_filter_result *r, struct nlattr **tb,
275 struct nlattr *est, bool ovr)
276 {
277 struct tcindex_filter_result new_filter_result, *old_r = r;
278 struct tcindex_filter_result cr;
279 struct tcindex_data *cp = NULL, *oldp;
280 struct tcindex_filter *f = NULL; /* make gcc behave */
281 int err, balloc = 0;
282 struct tcf_exts e;
283
284 err = tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
285 if (err < 0)
286 return err;
287 err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
288 if (err < 0)
289 goto errout;
290
291 err = -ENOMEM;
292 /* tcindex_data attributes must look atomic to classifier/lookup so
293 * allocate new tcindex data and RCU assign it onto root. Keeping
294 * perfect hash and hash pointers from old data.
295 */
296 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
297 if (!cp)
298 goto errout;
299
300 cp->mask = p->mask;
301 cp->shift = p->shift;
302 cp->hash = p->hash;
303 cp->alloc_hash = p->alloc_hash;
304 cp->fall_through = p->fall_through;
305 cp->tp = tp;
306
307 if (p->perfect) {
308 int i;
309
310 if (tcindex_alloc_perfect_hash(cp) < 0)
311 goto errout;
312 for (i = 0; i < cp->hash; i++)
313 cp->perfect[i].res = p->perfect[i].res;
314 balloc = 1;
315 }
316 cp->h = p->h;
317
318 err = tcindex_filter_result_init(&new_filter_result);
319 if (err < 0)
320 goto errout1;
321 err = tcindex_filter_result_init(&cr);
322 if (err < 0)
323 goto errout1;
324 if (old_r)
325 cr.res = r->res;
326
327 if (tb[TCA_TCINDEX_HASH])
328 cp->hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
329
330 if (tb[TCA_TCINDEX_MASK])
331 cp->mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
332
333 if (tb[TCA_TCINDEX_SHIFT])
334 cp->shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
335
336 err = -EBUSY;
337
338 /* Hash already allocated, make sure that we still meet the
339 * requirements for the allocated hash.
340 */
341 if (cp->perfect) {
342 if (!valid_perfect_hash(cp) ||
343 cp->hash > cp->alloc_hash)
344 goto errout_alloc;
345 } else if (cp->h && cp->hash != cp->alloc_hash) {
346 goto errout_alloc;
347 }
348
349 err = -EINVAL;
350 if (tb[TCA_TCINDEX_FALL_THROUGH])
351 cp->fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
352
353 if (!cp->hash) {
354 /* Hash not specified, use perfect hash if the upper limit
355 * of the hashing index is below the threshold.
356 */
357 if ((cp->mask >> cp->shift) < PERFECT_HASH_THRESHOLD)
358 cp->hash = (cp->mask >> cp->shift) + 1;
359 else
360 cp->hash = DEFAULT_HASH_SIZE;
361 }
362
363 if (!cp->perfect && !cp->h)
364 cp->alloc_hash = cp->hash;
365
366 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
367 * but then, we'd fail handles that may become valid after some future
368 * mask change. While this is extremely unlikely to ever matter,
369 * the check below is safer (and also more backwards-compatible).
370 */
371 if (cp->perfect || valid_perfect_hash(cp))
372 if (handle >= cp->alloc_hash)
373 goto errout_alloc;
374
375
376 err = -ENOMEM;
377 if (!cp->perfect && !cp->h) {
378 if (valid_perfect_hash(cp)) {
379 if (tcindex_alloc_perfect_hash(cp) < 0)
380 goto errout_alloc;
381 balloc = 1;
382 } else {
383 struct tcindex_filter __rcu **hash;
384
385 hash = kcalloc(cp->hash,
386 sizeof(struct tcindex_filter *),
387 GFP_KERNEL);
388
389 if (!hash)
390 goto errout_alloc;
391
392 cp->h = hash;
393 balloc = 2;
394 }
395 }
396
397 if (cp->perfect)
398 r = cp->perfect + handle;
399 else
400 r = tcindex_lookup(cp, handle) ? : &new_filter_result;
401
402 if (r == &new_filter_result) {
403 f = kzalloc(sizeof(*f), GFP_KERNEL);
404 if (!f)
405 goto errout_alloc;
406 f->key = handle;
407 f->next = NULL;
408 err = tcindex_filter_result_init(&f->result);
409 if (err < 0) {
410 kfree(f);
411 goto errout_alloc;
412 }
413 }
414
415 if (tb[TCA_TCINDEX_CLASSID]) {
416 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
417 tcf_bind_filter(tp, &cr.res, base);
418 }
419
420 if (old_r)
421 tcf_exts_change(&r->exts, &e);
422 else
423 tcf_exts_change(&cr.exts, &e);
424
425 if (old_r && old_r != r) {
426 err = tcindex_filter_result_init(old_r);
427 if (err < 0) {
428 kfree(f);
429 goto errout_alloc;
430 }
431 }
432
433 oldp = p;
434 r->res = cr.res;
435 rcu_assign_pointer(tp->root, cp);
436
437 if (r == &new_filter_result) {
438 struct tcindex_filter *nfp;
439 struct tcindex_filter __rcu **fp;
440
441 tcf_exts_change(&f->result.exts, &r->exts);
442
443 fp = cp->h + (handle % cp->hash);
444 for (nfp = rtnl_dereference(*fp);
445 nfp;
446 fp = &nfp->next, nfp = rtnl_dereference(*fp))
447 ; /* nothing */
448
449 rcu_assign_pointer(*fp, f);
450 }
451
452 if (oldp)
453 call_rcu(&oldp->rcu, __tcindex_partial_destroy);
454 return 0;
455
456 errout_alloc:
457 if (balloc == 1)
458 tcindex_free_perfect_hash(cp);
459 else if (balloc == 2)
460 kfree(cp->h);
461 errout1:
462 tcf_exts_destroy(&cr.exts);
463 tcf_exts_destroy(&new_filter_result.exts);
464 errout:
465 kfree(cp);
466 tcf_exts_destroy(&e);
467 return err;
468 }
469
470 static int
471 tcindex_change(struct net *net, struct sk_buff *in_skb,
472 struct tcf_proto *tp, unsigned long base, u32 handle,
473 struct nlattr **tca, void **arg, bool ovr)
474 {
475 struct nlattr *opt = tca[TCA_OPTIONS];
476 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
477 struct tcindex_data *p = rtnl_dereference(tp->root);
478 struct tcindex_filter_result *r = *arg;
479 int err;
480
481 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
482 "p %p,r %p,*arg %p\n",
483 tp, handle, tca, arg, opt, p, r, arg ? *arg : NULL);
484
485 if (!opt)
486 return 0;
487
488 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy, NULL);
489 if (err < 0)
490 return err;
491
492 return tcindex_set_parms(net, tp, base, handle, p, r, tb,
493 tca[TCA_RATE], ovr);
494 }
495
496 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
497 {
498 struct tcindex_data *p = rtnl_dereference(tp->root);
499 struct tcindex_filter *f, *next;
500 int i;
501
502 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
503 if (p->perfect) {
504 for (i = 0; i < p->hash; i++) {
505 if (!p->perfect[i].res.class)
506 continue;
507 if (walker->count >= walker->skip) {
508 if (walker->fn(tp, p->perfect + i, walker) < 0) {
509 walker->stop = 1;
510 return;
511 }
512 }
513 walker->count++;
514 }
515 }
516 if (!p->h)
517 return;
518 for (i = 0; i < p->hash; i++) {
519 for (f = rtnl_dereference(p->h[i]); f; f = next) {
520 next = rtnl_dereference(f->next);
521 if (walker->count >= walker->skip) {
522 if (walker->fn(tp, &f->result, walker) < 0) {
523 walker->stop = 1;
524 return;
525 }
526 }
527 walker->count++;
528 }
529 }
530 }
531
532 static void tcindex_destroy(struct tcf_proto *tp)
533 {
534 struct tcindex_data *p = rtnl_dereference(tp->root);
535 struct tcf_walker walker;
536
537 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
538 walker.count = 0;
539 walker.skip = 0;
540 walker.fn = tcindex_destroy_element;
541 tcindex_walk(tp, &walker);
542
543 call_rcu(&p->rcu, __tcindex_destroy);
544 }
545
546
547 static int tcindex_dump(struct net *net, struct tcf_proto *tp, void *fh,
548 struct sk_buff *skb, struct tcmsg *t)
549 {
550 struct tcindex_data *p = rtnl_dereference(tp->root);
551 struct tcindex_filter_result *r = fh;
552 struct nlattr *nest;
553
554 pr_debug("tcindex_dump(tp %p,fh %p,skb %p,t %p),p %p,r %p\n",
555 tp, fh, skb, t, p, r);
556 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
557
558 nest = nla_nest_start(skb, TCA_OPTIONS);
559 if (nest == NULL)
560 goto nla_put_failure;
561
562 if (!fh) {
563 t->tcm_handle = ~0; /* whatever ... */
564 if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) ||
565 nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) ||
566 nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) ||
567 nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
568 goto nla_put_failure;
569 nla_nest_end(skb, nest);
570 } else {
571 if (p->perfect) {
572 t->tcm_handle = r - p->perfect;
573 } else {
574 struct tcindex_filter *f;
575 struct tcindex_filter __rcu **fp;
576 int i;
577
578 t->tcm_handle = 0;
579 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
580 fp = &p->h[i];
581 for (f = rtnl_dereference(*fp);
582 !t->tcm_handle && f;
583 fp = &f->next, f = rtnl_dereference(*fp)) {
584 if (&f->result == r)
585 t->tcm_handle = f->key;
586 }
587 }
588 }
589 pr_debug("handle = %d\n", t->tcm_handle);
590 if (r->res.class &&
591 nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
592 goto nla_put_failure;
593
594 if (tcf_exts_dump(skb, &r->exts) < 0)
595 goto nla_put_failure;
596 nla_nest_end(skb, nest);
597
598 if (tcf_exts_dump_stats(skb, &r->exts) < 0)
599 goto nla_put_failure;
600 }
601
602 return skb->len;
603
604 nla_put_failure:
605 nla_nest_cancel(skb, nest);
606 return -1;
607 }
608
609 static void tcindex_bind_class(void *fh, u32 classid, unsigned long cl)
610 {
611 struct tcindex_filter_result *r = fh;
612
613 if (r && r->res.classid == classid)
614 r->res.class = cl;
615 }
616
617 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
618 .kind = "tcindex",
619 .classify = tcindex_classify,
620 .init = tcindex_init,
621 .destroy = tcindex_destroy,
622 .get = tcindex_get,
623 .change = tcindex_change,
624 .delete = tcindex_delete,
625 .walk = tcindex_walk,
626 .dump = tcindex_dump,
627 .bind_class = tcindex_bind_class,
628 .owner = THIS_MODULE,
629 };
630
631 static int __init init_tcindex(void)
632 {
633 return register_tcf_proto_ops(&cls_tcindex_ops);
634 }
635
636 static void __exit exit_tcindex(void)
637 {
638 unregister_tcf_proto_ops(&cls_tcindex_ops);
639 }
640
641 module_init(init_tcindex)
642 module_exit(exit_tcindex)
643 MODULE_LICENSE("GPL");
Linux with added FPC-III support