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
tcindex_filter_is_set(struct tcindex_filter_result * r)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 *
tcindex_lookup(struct tcindex_data * p,u16 key)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
tcindex_classify(struct sk_buff * skb,const struct tcf_proto * tp,struct tcf_result * res)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
tcindex_get(struct tcf_proto * tp,u32 handle)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
tcindex_put(struct tcf_proto * tp,unsigned long f)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
tcindex_init(struct tcf_proto * tp)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
tcindex_delete(struct tcf_proto * tp,unsigned long arg)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
tcindex_destroy_element(struct tcf_proto * tp,unsigned long arg,struct tcf_walker * walker)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
__tcindex_destroy(struct rcu_head * head)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
valid_perfect_hash(struct tcindex_data * p)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
tcindex_filter_result_init(struct tcindex_filter_result * r)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
__tcindex_partial_destroy(struct rcu_head * head)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
tcindex_set_parms(struct net * net,struct tcf_proto * tp,unsigned long base,u32 handle,struct tcindex_data * p,struct tcindex_filter_result * r,struct nlattr ** tb,struct nlattr * est,bool ovr)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 int i;
258
259 cp->perfect = kmemdup(p->perfect,
260 sizeof(*r) * cp->hash, GFP_KERNEL);
261 if (!cp->perfect)
262 goto errout;
263 for (i = 0; i < cp->hash; i++)
264 tcf_exts_init(&cp->perfect[i].exts,
265 TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
266 balloc = 1;
267 }
268 cp->h = p->h;
269
270 tcindex_filter_result_init(&new_filter_result);
271 tcindex_filter_result_init(&cr);
272 if (old_r)
273 cr.res = r->res;
274
275 if (tb[TCA_TCINDEX_HASH])
276 cp->hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
277
278 if (tb[TCA_TCINDEX_MASK])
279 cp->mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
280
281 if (tb[TCA_TCINDEX_SHIFT])
282 cp->shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
283
284 err = -EBUSY;
285
286 /* Hash already allocated, make sure that we still meet the
287 * requirements for the allocated hash.
288 */
289 if (cp->perfect) {
290 if (!valid_perfect_hash(cp) ||
291 cp->hash > cp->alloc_hash)
292 goto errout_alloc;
293 } else if (cp->h && cp->hash != cp->alloc_hash) {
294 goto errout_alloc;
295 }
296
297 err = -EINVAL;
298 if (tb[TCA_TCINDEX_FALL_THROUGH])
299 cp->fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
300
301 if (!cp->hash) {
302 /* Hash not specified, use perfect hash if the upper limit
303 * of the hashing index is below the threshold.
304 */
305 if ((cp->mask >> cp->shift) < PERFECT_HASH_THRESHOLD)
306 cp->hash = (cp->mask >> cp->shift) + 1;
307 else
308 cp->hash = DEFAULT_HASH_SIZE;
309 }
310
311 if (!cp->perfect && !cp->h)
312 cp->alloc_hash = cp->hash;
313
314 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
315 * but then, we'd fail handles that may become valid after some future
316 * mask change. While this is extremely unlikely to ever matter,
317 * the check below is safer (and also more backwards-compatible).
318 */
319 if (cp->perfect || valid_perfect_hash(cp))
320 if (handle >= cp->alloc_hash)
321 goto errout_alloc;
322
323
324 err = -ENOMEM;
325 if (!cp->perfect && !cp->h) {
326 if (valid_perfect_hash(cp)) {
327 int i;
328
329 cp->perfect = kcalloc(cp->hash, sizeof(*r), GFP_KERNEL);
330 if (!cp->perfect)
331 goto errout_alloc;
332 for (i = 0; i < cp->hash; i++)
333 tcf_exts_init(&cp->perfect[i].exts,
334 TCA_TCINDEX_ACT,
335 TCA_TCINDEX_POLICE);
336 balloc = 1;
337 } else {
338 struct tcindex_filter __rcu **hash;
339
340 hash = kcalloc(cp->hash,
341 sizeof(struct tcindex_filter *),
342 GFP_KERNEL);
343
344 if (!hash)
345 goto errout_alloc;
346
347 cp->h = hash;
348 balloc = 2;
349 }
350 }
351
352 if (cp->perfect)
353 r = cp->perfect + handle;
354 else
355 r = tcindex_lookup(cp, handle) ? : &new_filter_result;
356
357 if (r == &new_filter_result) {
358 f = kzalloc(sizeof(*f), GFP_KERNEL);
359 if (!f)
360 goto errout_alloc;
361 f->key = handle;
362 tcindex_filter_result_init(&f->result);
363 f->next = NULL;
364 }
365
366 if (tb[TCA_TCINDEX_CLASSID]) {
367 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
368 tcf_bind_filter(tp, &cr.res, base);
369 }
370
371 if (old_r)
372 tcf_exts_change(tp, &r->exts, &e);
373 else
374 tcf_exts_change(tp, &cr.exts, &e);
375
376 if (old_r && old_r != r)
377 tcindex_filter_result_init(old_r);
378
379 oldp = p;
380 r->res = cr.res;
381 rcu_assign_pointer(tp->root, cp);
382
383 if (r == &new_filter_result) {
384 struct tcindex_filter *nfp;
385 struct tcindex_filter __rcu **fp;
386
387 tcf_exts_change(tp, &f->result.exts, &r->exts);
388
389 fp = cp->h + (handle % cp->hash);
390 for (nfp = rtnl_dereference(*fp);
391 nfp;
392 fp = &nfp->next, nfp = rtnl_dereference(*fp))
393 ; /* nothing */
394
395 rcu_assign_pointer(*fp, f);
396 }
397
398 if (oldp)
399 call_rcu(&oldp->rcu, __tcindex_partial_destroy);
400 return 0;
401
402 errout_alloc:
403 if (balloc == 1)
404 kfree(cp->perfect);
405 else if (balloc == 2)
406 kfree(cp->h);
407 errout:
408 kfree(cp);
409 tcf_exts_destroy(&e);
410 return err;
411 }
412
413 static int
tcindex_change(struct net * net,struct sk_buff * in_skb,struct tcf_proto * tp,unsigned long base,u32 handle,struct nlattr ** tca,unsigned long * arg,bool ovr)414 tcindex_change(struct net *net, struct sk_buff *in_skb,
415 struct tcf_proto *tp, unsigned long base, u32 handle,
416 struct nlattr **tca, unsigned long *arg, bool ovr)
417 {
418 struct nlattr *opt = tca[TCA_OPTIONS];
419 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
420 struct tcindex_data *p = rtnl_dereference(tp->root);
421 struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
422 int err;
423
424 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
425 "p %p,r %p,*arg 0x%lx\n",
426 tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
427
428 if (!opt)
429 return 0;
430
431 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
432 if (err < 0)
433 return err;
434
435 return tcindex_set_parms(net, tp, base, handle, p, r, tb,
436 tca[TCA_RATE], ovr);
437 }
438
tcindex_walk(struct tcf_proto * tp,struct tcf_walker * walker)439 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
440 {
441 struct tcindex_data *p = rtnl_dereference(tp->root);
442 struct tcindex_filter *f, *next;
443 int i;
444
445 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
446 if (p->perfect) {
447 for (i = 0; i < p->hash; i++) {
448 if (!p->perfect[i].res.class)
449 continue;
450 if (walker->count >= walker->skip) {
451 if (walker->fn(tp,
452 (unsigned long) (p->perfect+i), walker)
453 < 0) {
454 walker->stop = 1;
455 return;
456 }
457 }
458 walker->count++;
459 }
460 }
461 if (!p->h)
462 return;
463 for (i = 0; i < p->hash; i++) {
464 for (f = rtnl_dereference(p->h[i]); f; f = next) {
465 next = rtnl_dereference(f->next);
466 if (walker->count >= walker->skip) {
467 if (walker->fn(tp, (unsigned long) &f->result,
468 walker) < 0) {
469 walker->stop = 1;
470 return;
471 }
472 }
473 walker->count++;
474 }
475 }
476 }
477
tcindex_destroy(struct tcf_proto * tp)478 static void tcindex_destroy(struct tcf_proto *tp)
479 {
480 struct tcindex_data *p = rtnl_dereference(tp->root);
481 struct tcf_walker walker;
482
483 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
484 walker.count = 0;
485 walker.skip = 0;
486 walker.fn = tcindex_destroy_element;
487 tcindex_walk(tp, &walker);
488
489 RCU_INIT_POINTER(tp->root, NULL);
490 call_rcu(&p->rcu, __tcindex_destroy);
491 }
492
493
tcindex_dump(struct net * net,struct tcf_proto * tp,unsigned long fh,struct sk_buff * skb,struct tcmsg * t)494 static int tcindex_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
495 struct sk_buff *skb, struct tcmsg *t)
496 {
497 struct tcindex_data *p = rtnl_dereference(tp->root);
498 struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
499 unsigned char *b = skb_tail_pointer(skb);
500 struct nlattr *nest;
501
502 pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
503 tp, fh, skb, t, p, r, b);
504 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
505
506 nest = nla_nest_start(skb, TCA_OPTIONS);
507 if (nest == NULL)
508 goto nla_put_failure;
509
510 if (!fh) {
511 t->tcm_handle = ~0; /* whatever ... */
512 if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) ||
513 nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) ||
514 nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) ||
515 nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
516 goto nla_put_failure;
517 nla_nest_end(skb, nest);
518 } else {
519 if (p->perfect) {
520 t->tcm_handle = r - p->perfect;
521 } else {
522 struct tcindex_filter *f;
523 struct tcindex_filter __rcu **fp;
524 int i;
525
526 t->tcm_handle = 0;
527 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
528 fp = &p->h[i];
529 for (f = rtnl_dereference(*fp);
530 !t->tcm_handle && f;
531 fp = &f->next, f = rtnl_dereference(*fp)) {
532 if (&f->result == r)
533 t->tcm_handle = f->key;
534 }
535 }
536 }
537 pr_debug("handle = %d\n", t->tcm_handle);
538 if (r->res.class &&
539 nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
540 goto nla_put_failure;
541
542 if (tcf_exts_dump(skb, &r->exts) < 0)
543 goto nla_put_failure;
544 nla_nest_end(skb, nest);
545
546 if (tcf_exts_dump_stats(skb, &r->exts) < 0)
547 goto nla_put_failure;
548 }
549
550 return skb->len;
551
552 nla_put_failure:
553 nlmsg_trim(skb, b);
554 return -1;
555 }
556
557 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
558 .kind = "tcindex",
559 .classify = tcindex_classify,
560 .init = tcindex_init,
561 .destroy = tcindex_destroy,
562 .get = tcindex_get,
563 .put = tcindex_put,
564 .change = tcindex_change,
565 .delete = tcindex_delete,
566 .walk = tcindex_walk,
567 .dump = tcindex_dump,
568 .owner = THIS_MODULE,
569 };
570
init_tcindex(void)571 static int __init init_tcindex(void)
572 {
573 return register_tcf_proto_ops(&cls_tcindex_ops);
574 }
575
exit_tcindex(void)576 static void __exit exit_tcindex(void)
577 {
578 unregister_tcf_proto_ops(&cls_tcindex_ops);
579 }
580
581 module_init(init_tcindex)
582 module_exit(exit_tcindex)
583 MODULE_LICENSE("GPL");
584