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[GitHub/moto-9609/android_kernel_motorola_exynos9610.git] / net / sched / cls_tcindex.c
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 };
31
32 struct tcindex_filter {
33 u16 key;
34 struct tcindex_filter_result result;
35 struct tcindex_filter __rcu *next;
36 struct rcu_head rcu;
37 };
38
39
40 struct tcindex_data {
41 struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
42 struct tcindex_filter __rcu **h; /* imperfect hash; */
43 struct tcf_proto *tp;
44 u16 mask; /* AND key with mask */
45 u32 shift; /* shift ANDed key to the right */
46 u32 hash; /* hash table size; 0 if undefined */
47 u32 alloc_hash; /* allocated size */
48 u32 fall_through; /* 0: only classify if explicit match */
49 struct rcu_head rcu;
50 };
51
52 static inline int
53 tcindex_filter_is_set(struct tcindex_filter_result *r)
54 {
55 return tcf_exts_is_predicative(&r->exts) || r->res.classid;
56 }
57
58 static struct tcindex_filter_result *
59 tcindex_lookup(struct tcindex_data *p, 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 unsigned long 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 0;
115 r = tcindex_lookup(p, handle);
116 return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL;
117 }
118
119
120 static void tcindex_put(struct tcf_proto *tp, unsigned long f)
121 {
122 pr_debug("tcindex_put(tp %p,f 0x%lx)\n", tp, f);
123 }
124
125
126 static int tcindex_init(struct tcf_proto *tp)
127 {
128 struct tcindex_data *p;
129
130 pr_debug("tcindex_init(tp %p)\n", tp);
131 p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL);
132 if (!p)
133 return -ENOMEM;
134
135 p->mask = 0xffff;
136 p->hash = DEFAULT_HASH_SIZE;
137 p->fall_through = 1;
138
139 rcu_assign_pointer(tp->root, p);
140 return 0;
141 }
142
143 static int
144 tcindex_delete(struct tcf_proto *tp, unsigned long arg)
145 {
146 struct tcindex_data *p = rtnl_dereference(tp->root);
147 struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
148 struct tcindex_filter __rcu **walk;
149 struct tcindex_filter *f = NULL;
150
151 pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p\n", tp, arg, p);
152 if (p->perfect) {
153 if (!r->res.class)
154 return -ENOENT;
155 } else {
156 int i;
157
158 for (i = 0; i < p->hash; i++) {
159 walk = p->h + i;
160 for (f = rtnl_dereference(*walk); f;
161 walk = &f->next, f = rtnl_dereference(*walk)) {
162 if (&f->result == r)
163 goto found;
164 }
165 }
166 return -ENOENT;
167
168 found:
169 rcu_assign_pointer(*walk, rtnl_dereference(f->next));
170 }
171 tcf_unbind_filter(tp, &r->res);
172 tcf_exts_destroy(&r->exts);
173 if (f)
174 kfree_rcu(f, rcu);
175 return 0;
176 }
177
178 static int tcindex_destroy_element(struct tcf_proto *tp,
179 unsigned long arg,
180 struct tcf_walker *walker)
181 {
182 return tcindex_delete(tp, arg);
183 }
184
185 static void __tcindex_destroy(struct rcu_head *head)
186 {
187 struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
188
189 kfree(p->perfect);
190 kfree(p->h);
191 kfree(p);
192 }
193
194 static inline int
195 valid_perfect_hash(struct tcindex_data *p)
196 {
197 return p->hash > (p->mask >> p->shift);
198 }
199
200 static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
201 [TCA_TCINDEX_HASH] = { .type = NLA_U32 },
202 [TCA_TCINDEX_MASK] = { .type = NLA_U16 },
203 [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
204 [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
205 [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
206 };
207
208 static void tcindex_filter_result_init(struct tcindex_filter_result *r)
209 {
210 memset(r, 0, sizeof(*r));
211 tcf_exts_init(&r->exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
212 }
213
214 static void __tcindex_partial_destroy(struct rcu_head *head)
215 {
216 struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
217
218 kfree(p->perfect);
219 kfree(p);
220 }
221
222 static int
223 tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
224 u32 handle, struct tcindex_data *p,
225 struct tcindex_filter_result *r, struct nlattr **tb,
226 struct nlattr *est, bool ovr)
227 {
228 int err, balloc = 0;
229 struct tcindex_filter_result new_filter_result, *old_r = r;
230 struct tcindex_filter_result cr;
231 struct tcindex_data *cp, *oldp;
232 struct tcindex_filter *f = NULL; /* make gcc behave */
233 struct tcf_exts e;
234
235 tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
236 err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
237 if (err < 0)
238 return err;
239
240 err = -ENOMEM;
241 /* tcindex_data attributes must look atomic to classifier/lookup so
242 * allocate new tcindex data and RCU assign it onto root. Keeping
243 * perfect hash and hash pointers from old data.
244 */
245 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
246 if (!cp)
247 goto errout;
248
249 cp->mask = p->mask;
250 cp->shift = p->shift;
251 cp->hash = p->hash;
252 cp->alloc_hash = p->alloc_hash;
253 cp->fall_through = p->fall_through;
254 cp->tp = tp;
255
256 if (p->perfect) {
257 cp->perfect = kmemdup(p->perfect,
258 sizeof(*r) * cp->hash, GFP_KERNEL);
259 if (!cp->perfect)
260 goto errout;
261 balloc = 1;
262 }
263 cp->h = p->h;
264
265 tcindex_filter_result_init(&new_filter_result);
266 tcindex_filter_result_init(&cr);
267 if (old_r)
268 cr.res = r->res;
269
270 if (tb[TCA_TCINDEX_HASH])
271 cp->hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
272
273 if (tb[TCA_TCINDEX_MASK])
274 cp->mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
275
276 if (tb[TCA_TCINDEX_SHIFT])
277 cp->shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
278
279 err = -EBUSY;
280
281 /* Hash already allocated, make sure that we still meet the
282 * requirements for the allocated hash.
283 */
284 if (cp->perfect) {
285 if (!valid_perfect_hash(cp) ||
286 cp->hash > cp->alloc_hash)
287 goto errout_alloc;
288 } else if (cp->h && cp->hash != cp->alloc_hash) {
289 goto errout_alloc;
290 }
291
292 err = -EINVAL;
293 if (tb[TCA_TCINDEX_FALL_THROUGH])
294 cp->fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
295
296 if (!cp->hash) {
297 /* Hash not specified, use perfect hash if the upper limit
298 * of the hashing index is below the threshold.
299 */
300 if ((cp->mask >> cp->shift) < PERFECT_HASH_THRESHOLD)
301 cp->hash = (cp->mask >> cp->shift) + 1;
302 else
303 cp->hash = DEFAULT_HASH_SIZE;
304 }
305
306 if (!cp->perfect && !cp->h)
307 cp->alloc_hash = cp->hash;
308
309 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
310 * but then, we'd fail handles that may become valid after some future
311 * mask change. While this is extremely unlikely to ever matter,
312 * the check below is safer (and also more backwards-compatible).
313 */
314 if (cp->perfect || valid_perfect_hash(cp))
315 if (handle >= cp->alloc_hash)
316 goto errout_alloc;
317
318
319 err = -ENOMEM;
320 if (!cp->perfect && !cp->h) {
321 if (valid_perfect_hash(cp)) {
322 int i;
323
324 cp->perfect = kcalloc(cp->hash, sizeof(*r), GFP_KERNEL);
325 if (!cp->perfect)
326 goto errout_alloc;
327 for (i = 0; i < cp->hash; i++)
328 tcf_exts_init(&cp->perfect[i].exts,
329 TCA_TCINDEX_ACT,
330 TCA_TCINDEX_POLICE);
331 balloc = 1;
332 } else {
333 struct tcindex_filter __rcu **hash;
334
335 hash = kcalloc(cp->hash,
336 sizeof(struct tcindex_filter *),
337 GFP_KERNEL);
338
339 if (!hash)
340 goto errout_alloc;
341
342 cp->h = hash;
343 balloc = 2;
344 }
345 }
346
347 if (cp->perfect)
348 r = cp->perfect + handle;
349 else
350 r = tcindex_lookup(cp, handle) ? : &new_filter_result;
351
352 if (r == &new_filter_result) {
353 f = kzalloc(sizeof(*f), GFP_KERNEL);
354 if (!f)
355 goto errout_alloc;
356 }
357
358 if (tb[TCA_TCINDEX_CLASSID]) {
359 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
360 tcf_bind_filter(tp, &cr.res, base);
361 }
362
363 if (old_r)
364 tcf_exts_change(tp, &r->exts, &e);
365 else
366 tcf_exts_change(tp, &cr.exts, &e);
367
368 if (old_r && old_r != r)
369 tcindex_filter_result_init(old_r);
370
371 oldp = p;
372 r->res = cr.res;
373 rcu_assign_pointer(tp->root, cp);
374
375 if (r == &new_filter_result) {
376 struct tcindex_filter *nfp;
377 struct tcindex_filter __rcu **fp;
378
379 f->key = handle;
380 f->result = new_filter_result;
381 f->next = NULL;
382
383 fp = cp->h + (handle % cp->hash);
384 for (nfp = rtnl_dereference(*fp);
385 nfp;
386 fp = &nfp->next, nfp = rtnl_dereference(*fp))
387 ; /* nothing */
388
389 rcu_assign_pointer(*fp, f);
390 }
391
392 if (oldp)
393 call_rcu(&oldp->rcu, __tcindex_partial_destroy);
394 return 0;
395
396 errout_alloc:
397 if (balloc == 1)
398 kfree(cp->perfect);
399 else if (balloc == 2)
400 kfree(cp->h);
401 errout:
402 kfree(cp);
403 tcf_exts_destroy(&e);
404 return err;
405 }
406
407 static int
408 tcindex_change(struct net *net, struct sk_buff *in_skb,
409 struct tcf_proto *tp, unsigned long base, u32 handle,
410 struct nlattr **tca, unsigned long *arg, bool ovr)
411 {
412 struct nlattr *opt = tca[TCA_OPTIONS];
413 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
414 struct tcindex_data *p = rtnl_dereference(tp->root);
415 struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
416 int err;
417
418 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
419 "p %p,r %p,*arg 0x%lx\n",
420 tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
421
422 if (!opt)
423 return 0;
424
425 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
426 if (err < 0)
427 return err;
428
429 return tcindex_set_parms(net, tp, base, handle, p, r, tb,
430 tca[TCA_RATE], ovr);
431 }
432
433 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
434 {
435 struct tcindex_data *p = rtnl_dereference(tp->root);
436 struct tcindex_filter *f, *next;
437 int i;
438
439 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
440 if (p->perfect) {
441 for (i = 0; i < p->hash; i++) {
442 if (!p->perfect[i].res.class)
443 continue;
444 if (walker->count >= walker->skip) {
445 if (walker->fn(tp,
446 (unsigned long) (p->perfect+i), walker)
447 < 0) {
448 walker->stop = 1;
449 return;
450 }
451 }
452 walker->count++;
453 }
454 }
455 if (!p->h)
456 return;
457 for (i = 0; i < p->hash; i++) {
458 for (f = rtnl_dereference(p->h[i]); f; f = next) {
459 next = rtnl_dereference(f->next);
460 if (walker->count >= walker->skip) {
461 if (walker->fn(tp, (unsigned long) &f->result,
462 walker) < 0) {
463 walker->stop = 1;
464 return;
465 }
466 }
467 walker->count++;
468 }
469 }
470 }
471
472 static void tcindex_destroy(struct tcf_proto *tp)
473 {
474 struct tcindex_data *p = rtnl_dereference(tp->root);
475 struct tcf_walker walker;
476
477 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
478 walker.count = 0;
479 walker.skip = 0;
480 walker.fn = tcindex_destroy_element;
481 tcindex_walk(tp, &walker);
482
483 RCU_INIT_POINTER(tp->root, NULL);
484 call_rcu(&p->rcu, __tcindex_destroy);
485 }
486
487
488 static int tcindex_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
489 struct sk_buff *skb, struct tcmsg *t)
490 {
491 struct tcindex_data *p = rtnl_dereference(tp->root);
492 struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
493 unsigned char *b = skb_tail_pointer(skb);
494 struct nlattr *nest;
495
496 pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
497 tp, fh, skb, t, p, r, b);
498 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
499
500 nest = nla_nest_start(skb, TCA_OPTIONS);
501 if (nest == NULL)
502 goto nla_put_failure;
503
504 if (!fh) {
505 t->tcm_handle = ~0; /* whatever ... */
506 if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) ||
507 nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) ||
508 nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) ||
509 nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
510 goto nla_put_failure;
511 nla_nest_end(skb, nest);
512 } else {
513 if (p->perfect) {
514 t->tcm_handle = r - p->perfect;
515 } else {
516 struct tcindex_filter *f;
517 struct tcindex_filter __rcu **fp;
518 int i;
519
520 t->tcm_handle = 0;
521 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
522 fp = &p->h[i];
523 for (f = rtnl_dereference(*fp);
524 !t->tcm_handle && f;
525 fp = &f->next, f = rtnl_dereference(*fp)) {
526 if (&f->result == r)
527 t->tcm_handle = f->key;
528 }
529 }
530 }
531 pr_debug("handle = %d\n", t->tcm_handle);
532 if (r->res.class &&
533 nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
534 goto nla_put_failure;
535
536 if (tcf_exts_dump(skb, &r->exts) < 0)
537 goto nla_put_failure;
538 nla_nest_end(skb, nest);
539
540 if (tcf_exts_dump_stats(skb, &r->exts) < 0)
541 goto nla_put_failure;
542 }
543
544 return skb->len;
545
546 nla_put_failure:
547 nlmsg_trim(skb, b);
548 return -1;
549 }
550
551 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
552 .kind = "tcindex",
553 .classify = tcindex_classify,
554 .init = tcindex_init,
555 .destroy = tcindex_destroy,
556 .get = tcindex_get,
557 .put = tcindex_put,
558 .change = tcindex_change,
559 .delete = tcindex_delete,
560 .walk = tcindex_walk,
561 .dump = tcindex_dump,
562 .owner = THIS_MODULE,
563 };
564
565 static int __init init_tcindex(void)
566 {
567 return register_tcf_proto_ops(&cls_tcindex_ops);
568 }
569
570 static void __exit exit_tcindex(void)
571 {
572 unregister_tcf_proto_ops(&cls_tcindex_ops);
573 }
574
575 module_init(init_tcindex)
576 module_exit(exit_tcindex)
577 MODULE_LICENSE("GPL");