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
tcindex_init(struct tcf_proto * tp)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 int
tcindex_delete(struct tcf_proto * tp,unsigned long arg)137 tcindex_delete(struct tcf_proto *tp, unsigned long arg)
138 {
139 struct tcindex_data *p = rtnl_dereference(tp->root);
140 struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
141 struct tcindex_filter __rcu **walk;
142 struct tcindex_filter *f = NULL;
143
144 pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p\n", tp, arg, p);
145 if (p->perfect) {
146 if (!r->res.class)
147 return -ENOENT;
148 } else {
149 int i;
150
151 for (i = 0; i < p->hash; i++) {
152 walk = p->h + i;
153 for (f = rtnl_dereference(*walk); f;
154 walk = &f->next, f = rtnl_dereference(*walk)) {
155 if (&f->result == r)
156 goto found;
157 }
158 }
159 return -ENOENT;
160
161 found:
162 rcu_assign_pointer(*walk, rtnl_dereference(f->next));
163 }
164 tcf_unbind_filter(tp, &r->res);
165 tcf_exts_destroy(&r->exts);
166 if (f)
167 kfree_rcu(f, rcu);
168 return 0;
169 }
170
tcindex_destroy_element(struct tcf_proto * tp,unsigned long arg,struct tcf_walker * walker)171 static int tcindex_destroy_element(struct tcf_proto *tp,
172 unsigned long arg,
173 struct tcf_walker *walker)
174 {
175 return tcindex_delete(tp, arg);
176 }
177
__tcindex_destroy(struct rcu_head * head)178 static void __tcindex_destroy(struct rcu_head *head)
179 {
180 struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
181
182 kfree(p->perfect);
183 kfree(p->h);
184 kfree(p);
185 }
186
187 static inline int
valid_perfect_hash(struct tcindex_data * p)188 valid_perfect_hash(struct tcindex_data *p)
189 {
190 return p->hash > (p->mask >> p->shift);
191 }
192
193 static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
194 [TCA_TCINDEX_HASH] = { .type = NLA_U32 },
195 [TCA_TCINDEX_MASK] = { .type = NLA_U16 },
196 [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
197 [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
198 [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
199 };
200
tcindex_filter_result_init(struct tcindex_filter_result * r)201 static void tcindex_filter_result_init(struct tcindex_filter_result *r)
202 {
203 memset(r, 0, sizeof(*r));
204 tcf_exts_init(&r->exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
205 }
206
__tcindex_partial_destroy(struct rcu_head * head)207 static void __tcindex_partial_destroy(struct rcu_head *head)
208 {
209 struct tcindex_data *p = container_of(head, struct tcindex_data, rcu);
210
211 kfree(p->perfect);
212 kfree(p);
213 }
214
215 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)216 tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
217 u32 handle, struct tcindex_data *p,
218 struct tcindex_filter_result *r, struct nlattr **tb,
219 struct nlattr *est, bool ovr)
220 {
221 int err, balloc = 0;
222 struct tcindex_filter_result new_filter_result, *old_r = r;
223 struct tcindex_filter_result cr;
224 struct tcindex_data *cp, *oldp;
225 struct tcindex_filter *f = NULL; /* make gcc behave */
226 struct tcf_exts e;
227
228 tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
229 err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
230 if (err < 0)
231 return err;
232
233 err = -ENOMEM;
234 /* tcindex_data attributes must look atomic to classifier/lookup so
235 * allocate new tcindex data and RCU assign it onto root. Keeping
236 * perfect hash and hash pointers from old data.
237 */
238 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
239 if (!cp)
240 goto errout;
241
242 cp->mask = p->mask;
243 cp->shift = p->shift;
244 cp->hash = p->hash;
245 cp->alloc_hash = p->alloc_hash;
246 cp->fall_through = p->fall_through;
247 cp->tp = tp;
248
249 if (p->perfect) {
250 int i;
251
252 cp->perfect = kmemdup(p->perfect,
253 sizeof(*r) * cp->hash, GFP_KERNEL);
254 if (!cp->perfect)
255 goto errout;
256 for (i = 0; i < cp->hash; i++)
257 tcf_exts_init(&cp->perfect[i].exts,
258 TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
259 balloc = 1;
260 }
261 cp->h = p->h;
262
263 tcindex_filter_result_init(&new_filter_result);
264 tcindex_filter_result_init(&cr);
265 if (old_r)
266 cr.res = r->res;
267
268 if (tb[TCA_TCINDEX_HASH])
269 cp->hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
270
271 if (tb[TCA_TCINDEX_MASK])
272 cp->mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
273
274 if (tb[TCA_TCINDEX_SHIFT])
275 cp->shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
276
277 err = -EBUSY;
278
279 /* Hash already allocated, make sure that we still meet the
280 * requirements for the allocated hash.
281 */
282 if (cp->perfect) {
283 if (!valid_perfect_hash(cp) ||
284 cp->hash > cp->alloc_hash)
285 goto errout_alloc;
286 } else if (cp->h && cp->hash != cp->alloc_hash) {
287 goto errout_alloc;
288 }
289
290 err = -EINVAL;
291 if (tb[TCA_TCINDEX_FALL_THROUGH])
292 cp->fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
293
294 if (!cp->hash) {
295 /* Hash not specified, use perfect hash if the upper limit
296 * of the hashing index is below the threshold.
297 */
298 if ((cp->mask >> cp->shift) < PERFECT_HASH_THRESHOLD)
299 cp->hash = (cp->mask >> cp->shift) + 1;
300 else
301 cp->hash = DEFAULT_HASH_SIZE;
302 }
303
304 if (!cp->perfect && !cp->h)
305 cp->alloc_hash = cp->hash;
306
307 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
308 * but then, we'd fail handles that may become valid after some future
309 * mask change. While this is extremely unlikely to ever matter,
310 * the check below is safer (and also more backwards-compatible).
311 */
312 if (cp->perfect || valid_perfect_hash(cp))
313 if (handle >= cp->alloc_hash)
314 goto errout_alloc;
315
316
317 err = -ENOMEM;
318 if (!cp->perfect && !cp->h) {
319 if (valid_perfect_hash(cp)) {
320 int i;
321
322 cp->perfect = kcalloc(cp->hash, sizeof(*r), GFP_KERNEL);
323 if (!cp->perfect)
324 goto errout_alloc;
325 for (i = 0; i < cp->hash; i++)
326 tcf_exts_init(&cp->perfect[i].exts,
327 TCA_TCINDEX_ACT,
328 TCA_TCINDEX_POLICE);
329 balloc = 1;
330 } else {
331 struct tcindex_filter __rcu **hash;
332
333 hash = kcalloc(cp->hash,
334 sizeof(struct tcindex_filter *),
335 GFP_KERNEL);
336
337 if (!hash)
338 goto errout_alloc;
339
340 cp->h = hash;
341 balloc = 2;
342 }
343 }
344
345 if (cp->perfect)
346 r = cp->perfect + handle;
347 else
348 r = tcindex_lookup(cp, handle) ? : &new_filter_result;
349
350 if (r == &new_filter_result) {
351 f = kzalloc(sizeof(*f), GFP_KERNEL);
352 if (!f)
353 goto errout_alloc;
354 f->key = handle;
355 tcindex_filter_result_init(&f->result);
356 f->next = NULL;
357 }
358
359 if (tb[TCA_TCINDEX_CLASSID]) {
360 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
361 tcf_bind_filter(tp, &cr.res, base);
362 }
363
364 if (old_r)
365 tcf_exts_change(tp, &r->exts, &e);
366 else
367 tcf_exts_change(tp, &cr.exts, &e);
368
369 if (old_r && old_r != r)
370 tcindex_filter_result_init(old_r);
371
372 oldp = p;
373 r->res = cr.res;
374 rcu_assign_pointer(tp->root, cp);
375
376 if (r == &new_filter_result) {
377 struct tcindex_filter *nfp;
378 struct tcindex_filter __rcu **fp;
379
380 tcf_exts_change(tp, &f->result.exts, &r->exts);
381
382 fp = cp->h + (handle % cp->hash);
383 for (nfp = rtnl_dereference(*fp);
384 nfp;
385 fp = &nfp->next, nfp = rtnl_dereference(*fp))
386 ; /* nothing */
387
388 rcu_assign_pointer(*fp, f);
389 }
390
391 if (oldp)
392 call_rcu(&oldp->rcu, __tcindex_partial_destroy);
393 return 0;
394
395 errout_alloc:
396 if (balloc == 1)
397 kfree(cp->perfect);
398 else if (balloc == 2)
399 kfree(cp->h);
400 errout:
401 kfree(cp);
402 tcf_exts_destroy(&e);
403 return err;
404 }
405
406 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)407 tcindex_change(struct net *net, struct sk_buff *in_skb,
408 struct tcf_proto *tp, unsigned long base, u32 handle,
409 struct nlattr **tca, unsigned long *arg, bool ovr)
410 {
411 struct nlattr *opt = tca[TCA_OPTIONS];
412 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
413 struct tcindex_data *p = rtnl_dereference(tp->root);
414 struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
415 int err;
416
417 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
418 "p %p,r %p,*arg 0x%lx\n",
419 tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
420
421 if (!opt)
422 return 0;
423
424 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
425 if (err < 0)
426 return err;
427
428 return tcindex_set_parms(net, tp, base, handle, p, r, tb,
429 tca[TCA_RATE], ovr);
430 }
431
tcindex_walk(struct tcf_proto * tp,struct tcf_walker * walker)432 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
433 {
434 struct tcindex_data *p = rtnl_dereference(tp->root);
435 struct tcindex_filter *f, *next;
436 int i;
437
438 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
439 if (p->perfect) {
440 for (i = 0; i < p->hash; i++) {
441 if (!p->perfect[i].res.class)
442 continue;
443 if (walker->count >= walker->skip) {
444 if (walker->fn(tp,
445 (unsigned long) (p->perfect+i), walker)
446 < 0) {
447 walker->stop = 1;
448 return;
449 }
450 }
451 walker->count++;
452 }
453 }
454 if (!p->h)
455 return;
456 for (i = 0; i < p->hash; i++) {
457 for (f = rtnl_dereference(p->h[i]); f; f = next) {
458 next = rtnl_dereference(f->next);
459 if (walker->count >= walker->skip) {
460 if (walker->fn(tp, (unsigned long) &f->result,
461 walker) < 0) {
462 walker->stop = 1;
463 return;
464 }
465 }
466 walker->count++;
467 }
468 }
469 }
470
tcindex_destroy(struct tcf_proto * tp,bool force)471 static bool tcindex_destroy(struct tcf_proto *tp, bool force)
472 {
473 struct tcindex_data *p = rtnl_dereference(tp->root);
474 struct tcf_walker walker;
475
476 if (!force)
477 return false;
478
479 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
480 walker.count = 0;
481 walker.skip = 0;
482 walker.fn = tcindex_destroy_element;
483 tcindex_walk(tp, &walker);
484
485 RCU_INIT_POINTER(tp->root, NULL);
486 call_rcu(&p->rcu, __tcindex_destroy);
487 return true;
488 }
489
490
tcindex_dump(struct net * net,struct tcf_proto * tp,unsigned long fh,struct sk_buff * skb,struct tcmsg * t)491 static int tcindex_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
492 struct sk_buff *skb, struct tcmsg *t)
493 {
494 struct tcindex_data *p = rtnl_dereference(tp->root);
495 struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
496 struct nlattr *nest;
497
498 pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p\n",
499 tp, fh, skb, t, p, r);
500 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
501
502 nest = nla_nest_start(skb, TCA_OPTIONS);
503 if (nest == NULL)
504 goto nla_put_failure;
505
506 if (!fh) {
507 t->tcm_handle = ~0; /* whatever ... */
508 if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) ||
509 nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) ||
510 nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) ||
511 nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
512 goto nla_put_failure;
513 nla_nest_end(skb, nest);
514 } else {
515 if (p->perfect) {
516 t->tcm_handle = r - p->perfect;
517 } else {
518 struct tcindex_filter *f;
519 struct tcindex_filter __rcu **fp;
520 int i;
521
522 t->tcm_handle = 0;
523 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
524 fp = &p->h[i];
525 for (f = rtnl_dereference(*fp);
526 !t->tcm_handle && f;
527 fp = &f->next, f = rtnl_dereference(*fp)) {
528 if (&f->result == r)
529 t->tcm_handle = f->key;
530 }
531 }
532 }
533 pr_debug("handle = %d\n", t->tcm_handle);
534 if (r->res.class &&
535 nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
536 goto nla_put_failure;
537
538 if (tcf_exts_dump(skb, &r->exts) < 0)
539 goto nla_put_failure;
540 nla_nest_end(skb, nest);
541
542 if (tcf_exts_dump_stats(skb, &r->exts) < 0)
543 goto nla_put_failure;
544 }
545
546 return skb->len;
547
548 nla_put_failure:
549 nla_nest_cancel(skb, nest);
550 return -1;
551 }
552
553 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
554 .kind = "tcindex",
555 .classify = tcindex_classify,
556 .init = tcindex_init,
557 .destroy = tcindex_destroy,
558 .get = tcindex_get,
559 .change = tcindex_change,
560 .delete = tcindex_delete,
561 .walk = tcindex_walk,
562 .dump = tcindex_dump,
563 .owner = THIS_MODULE,
564 };
565
init_tcindex(void)566 static int __init init_tcindex(void)
567 {
568 return register_tcf_proto_ops(&cls_tcindex_ops);
569 }
570
exit_tcindex(void)571 static void __exit exit_tcindex(void)
572 {
573 unregister_tcf_proto_ops(&cls_tcindex_ops);
574 }
575
576 module_init(init_tcindex)
577 module_exit(exit_tcindex)
578 MODULE_LICENSE("GPL");
579