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[NET_SCHED]: Use typeful attribute construction helpers
[linux-2.6/sactl.git] / net / sched / cls_tcindex.c
blob7d46df7eac0955eff20eddb9cae3a33951df65d0
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 <net/act_api.h>
13 #include <net/netlink.h>
14 #include <net/pkt_cls.h>
15
16
17 /*
18 * Not quite sure if we need all the xchgs Alexey uses when accessing things.
19 * Can always add them later ... :)
20 */
21
22 /*
23 * Passing parameters to the root seems to be done more awkwardly than really
24 * necessary. At least, u32 doesn't seem to use such dirty hacks. To be
25 * verified. FIXME.
26 */
27
28 #define PERFECT_HASH_THRESHOLD 64 /* use perfect hash if not bigger */
29 #define DEFAULT_HASH_SIZE 64 /* optimized for diffserv */
30
31
32 #define PRIV(tp) ((struct tcindex_data *) (tp)->root)
33
34
35 struct tcindex_filter_result {
36 struct tcf_exts exts;
37 struct tcf_result res;
38 };
39
40 struct tcindex_filter {
41 u16 key;
42 struct tcindex_filter_result result;
43 struct tcindex_filter *next;
44 };
45
46
47 struct tcindex_data {
48 struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
49 struct tcindex_filter **h; /* imperfect hash; only used if !perfect;
50 NULL if unused */
51 u16 mask; /* AND key with mask */
52 int shift; /* shift ANDed key to the right */
53 int hash; /* hash table size; 0 if undefined */
54 int alloc_hash; /* allocated size */
55 int fall_through; /* 0: only classify if explicit match */
56 };
57
58 static struct tcf_ext_map tcindex_ext_map = {
59 .police = TCA_TCINDEX_POLICE,
60 .action = TCA_TCINDEX_ACT
61 };
62
63 static inline int
64 tcindex_filter_is_set(struct tcindex_filter_result *r)
65 {
66 return tcf_exts_is_predicative(&r->exts) || r->res.classid;
67 }
68
69 static struct tcindex_filter_result *
70 tcindex_lookup(struct tcindex_data *p, u16 key)
71 {
72 struct tcindex_filter *f;
73
74 if (p->perfect)
75 return tcindex_filter_is_set(p->perfect + key) ?
76 p->perfect + key : NULL;
77 else if (p->h) {
78 for (f = p->h[key % p->hash]; f; f = f->next)
79 if (f->key == key)
80 return &f->result;
81 }
82
83 return NULL;
84 }
85
86
87 static int tcindex_classify(struct sk_buff *skb, struct tcf_proto *tp,
88 struct tcf_result *res)
89 {
90 struct tcindex_data *p = PRIV(tp);
91 struct tcindex_filter_result *f;
92 int key = (skb->tc_index & p->mask) >> p->shift;
93
94 pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n",
95 skb, tp, res, p);
96
97 f = tcindex_lookup(p, key);
98 if (!f) {
99 if (!p->fall_through)
100 return -1;
101 res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key);
102 res->class = 0;
103 pr_debug("alg 0x%x\n", res->classid);
104 return 0;
105 }
106 *res = f->res;
107 pr_debug("map 0x%x\n", res->classid);
108
109 return tcf_exts_exec(skb, &f->exts, res);
110 }
111
112
113 static unsigned long tcindex_get(struct tcf_proto *tp, u32 handle)
114 {
115 struct tcindex_data *p = PRIV(tp);
116 struct tcindex_filter_result *r;
117
118 pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle);
119 if (p->perfect && handle >= p->alloc_hash)
120 return 0;
121 r = tcindex_lookup(p, handle);
122 return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL;
123 }
124
125
126 static void tcindex_put(struct tcf_proto *tp, unsigned long f)
127 {
128 pr_debug("tcindex_put(tp %p,f 0x%lx)\n", tp, f);
129 }
130
131
132 static int tcindex_init(struct tcf_proto *tp)
133 {
134 struct tcindex_data *p;
135
136 pr_debug("tcindex_init(tp %p)\n", tp);
137 p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL);
138 if (!p)
139 return -ENOMEM;
140
141 p->mask = 0xffff;
142 p->hash = DEFAULT_HASH_SIZE;
143 p->fall_through = 1;
144
145 tp->root = p;
146 return 0;
147 }
148
149
150 static int
151 __tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
152 {
153 struct tcindex_data *p = PRIV(tp);
154 struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
155 struct tcindex_filter *f = NULL;
156
157 pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n", tp, arg, p, f);
158 if (p->perfect) {
159 if (!r->res.class)
160 return -ENOENT;
161 } else {
162 int i;
163 struct tcindex_filter **walk = NULL;
164
165 for (i = 0; i < p->hash; i++)
166 for (walk = p->h+i; *walk; walk = &(*walk)->next)
167 if (&(*walk)->result == r)
168 goto found;
169 return -ENOENT;
170
171 found:
172 f = *walk;
173 if (lock)
174 tcf_tree_lock(tp);
175 *walk = f->next;
176 if (lock)
177 tcf_tree_unlock(tp);
178 }
179 tcf_unbind_filter(tp, &r->res);
180 tcf_exts_destroy(tp, &r->exts);
181 kfree(f);
182 return 0;
183 }
184
185 static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
186 {
187 return __tcindex_delete(tp, arg, 1);
188 }
189
190 static inline int
191 valid_perfect_hash(struct tcindex_data *p)
192 {
193 return p->hash > (p->mask >> p->shift);
194 }
195
196 static int
197 tcindex_set_parms(struct tcf_proto *tp, unsigned long base, u32 handle,
198 struct tcindex_data *p, struct tcindex_filter_result *r,
199 struct nlattr **tb, struct nlattr *est)
200 {
201 int err, balloc = 0;
202 struct tcindex_filter_result new_filter_result, *old_r = r;
203 struct tcindex_filter_result cr;
204 struct tcindex_data cp;
205 struct tcindex_filter *f = NULL; /* make gcc behave */
206 struct tcf_exts e;
207
208 err = tcf_exts_validate(tp, tb, est, &e, &tcindex_ext_map);
209 if (err < 0)
210 return err;
211
212 memcpy(&cp, p, sizeof(cp));
213 memset(&new_filter_result, 0, sizeof(new_filter_result));
214
215 if (old_r)
216 memcpy(&cr, r, sizeof(cr));
217 else
218 memset(&cr, 0, sizeof(cr));
219
220 err = -EINVAL;
221 if (tb[TCA_TCINDEX_HASH]) {
222 if (nla_len(tb[TCA_TCINDEX_HASH]) < sizeof(u32))
223 goto errout;
224 cp.hash = *(u32 *) nla_data(tb[TCA_TCINDEX_HASH]);
225 }
226
227 if (tb[TCA_TCINDEX_MASK]) {
228 if (nla_len(tb[TCA_TCINDEX_MASK]) < sizeof(u16))
229 goto errout;
230 cp.mask = *(u16 *) nla_data(tb[TCA_TCINDEX_MASK]);
231 }
232
233 if (tb[TCA_TCINDEX_SHIFT]) {
234 if (nla_len(tb[TCA_TCINDEX_SHIFT]) < sizeof(int))
235 goto errout;
236 cp.shift = *(int *) nla_data(tb[TCA_TCINDEX_SHIFT]);
237 }
238
239 err = -EBUSY;
240 /* Hash already allocated, make sure that we still meet the
241 * requirements for the allocated hash.
242 */
243 if (cp.perfect) {
244 if (!valid_perfect_hash(&cp) ||
245 cp.hash > cp.alloc_hash)
246 goto errout;
247 } else if (cp.h && cp.hash != cp.alloc_hash)
248 goto errout;
249
250 err = -EINVAL;
251 if (tb[TCA_TCINDEX_FALL_THROUGH]) {
252 if (nla_len(tb[TCA_TCINDEX_FALL_THROUGH]) < sizeof(u32))
253 goto errout;
254 cp.fall_through =
255 *(u32 *) nla_data(tb[TCA_TCINDEX_FALL_THROUGH]);
256 }
257
258 if (!cp.hash) {
259 /* Hash not specified, use perfect hash if the upper limit
260 * of the hashing index is below the threshold.
261 */
262 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
263 cp.hash = (cp.mask >> cp.shift)+1;
264 else
265 cp.hash = DEFAULT_HASH_SIZE;
266 }
267
268 if (!cp.perfect && !cp.h)
269 cp.alloc_hash = cp.hash;
270
271 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
272 * but then, we'd fail handles that may become valid after some future
273 * mask change. While this is extremely unlikely to ever matter,
274 * the check below is safer (and also more backwards-compatible).
275 */
276 if (cp.perfect || valid_perfect_hash(&cp))
277 if (handle >= cp.alloc_hash)
278 goto errout;
279
280
281 err = -ENOMEM;
282 if (!cp.perfect && !cp.h) {
283 if (valid_perfect_hash(&cp)) {
284 cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
285 if (!cp.perfect)
286 goto errout;
287 balloc = 1;
288 } else {
289 cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
290 if (!cp.h)
291 goto errout;
292 balloc = 2;
293 }
294 }
295
296 if (cp.perfect)
297 r = cp.perfect + handle;
298 else
299 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
300
301 if (r == &new_filter_result) {
302 f = kzalloc(sizeof(*f), GFP_KERNEL);
303 if (!f)
304 goto errout_alloc;
305 }
306
307 if (tb[TCA_TCINDEX_CLASSID]) {
308 cr.res.classid = *(u32 *) nla_data(tb[TCA_TCINDEX_CLASSID]);
309 tcf_bind_filter(tp, &cr.res, base);
310 }
311
312 tcf_exts_change(tp, &cr.exts, &e);
313
314 tcf_tree_lock(tp);
315 if (old_r && old_r != r)
316 memset(old_r, 0, sizeof(*old_r));
317
318 memcpy(p, &cp, sizeof(cp));
319 memcpy(r, &cr, sizeof(cr));
320
321 if (r == &new_filter_result) {
322 struct tcindex_filter **fp;
323
324 f->key = handle;
325 f->result = new_filter_result;
326 f->next = NULL;
327 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
328 /* nothing */;
329 *fp = f;
330 }
331 tcf_tree_unlock(tp);
332
333 return 0;
334
335 errout_alloc:
336 if (balloc == 1)
337 kfree(cp.perfect);
338 else if (balloc == 2)
339 kfree(cp.h);
340 errout:
341 tcf_exts_destroy(tp, &e);
342 return err;
343 }
344
345 static int
346 tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
347 struct nlattr **tca, unsigned long *arg)
348 {
349 struct nlattr *opt = tca[TCA_OPTIONS];
350 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
351 struct tcindex_data *p = PRIV(tp);
352 struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
353 int err;
354
355 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
356 "p %p,r %p,*arg 0x%lx\n",
357 tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
358
359 if (!opt)
360 return 0;
361
362 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, NULL);
363 if (err < 0)
364 return err;
365
366 return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE]);
367 }
368
369
370 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
371 {
372 struct tcindex_data *p = PRIV(tp);
373 struct tcindex_filter *f, *next;
374 int i;
375
376 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
377 if (p->perfect) {
378 for (i = 0; i < p->hash; i++) {
379 if (!p->perfect[i].res.class)
380 continue;
381 if (walker->count >= walker->skip) {
382 if (walker->fn(tp,
383 (unsigned long) (p->perfect+i), walker)
384 < 0) {
385 walker->stop = 1;
386 return;
387 }
388 }
389 walker->count++;
390 }
391 }
392 if (!p->h)
393 return;
394 for (i = 0; i < p->hash; i++) {
395 for (f = p->h[i]; f; f = next) {
396 next = f->next;
397 if (walker->count >= walker->skip) {
398 if (walker->fn(tp, (unsigned long) &f->result,
399 walker) < 0) {
400 walker->stop = 1;
401 return;
402 }
403 }
404 walker->count++;
405 }
406 }
407 }
408
409
410 static int tcindex_destroy_element(struct tcf_proto *tp,
411 unsigned long arg, struct tcf_walker *walker)
412 {
413 return __tcindex_delete(tp, arg, 0);
414 }
415
416
417 static void tcindex_destroy(struct tcf_proto *tp)
418 {
419 struct tcindex_data *p = PRIV(tp);
420 struct tcf_walker walker;
421
422 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
423 walker.count = 0;
424 walker.skip = 0;
425 walker.fn = &tcindex_destroy_element;
426 tcindex_walk(tp, &walker);
427 kfree(p->perfect);
428 kfree(p->h);
429 kfree(p);
430 tp->root = NULL;
431 }
432
433
434 static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
435 struct sk_buff *skb, struct tcmsg *t)
436 {
437 struct tcindex_data *p = PRIV(tp);
438 struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
439 unsigned char *b = skb_tail_pointer(skb);
440 struct nlattr *nest;
441
442 pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
443 tp, fh, skb, t, p, r, b);
444 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
445
446 nest = nla_nest_start(skb, TCA_OPTIONS);
447 if (nest == NULL)
448 goto nla_put_failure;
449
450 if (!fh) {
451 t->tcm_handle = ~0; /* whatever ... */
452 NLA_PUT_U32(skb, TCA_TCINDEX_HASH, p->hash);
453 NLA_PUT_U16(skb, TCA_TCINDEX_MASK, p->mask);
454 NLA_PUT_U32(skb, TCA_TCINDEX_SHIFT, p->shift);
455 NLA_PUT_U32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through);
456 nla_nest_end(skb, nest);
457 } else {
458 if (p->perfect) {
459 t->tcm_handle = r-p->perfect;
460 } else {
461 struct tcindex_filter *f;
462 int i;
463
464 t->tcm_handle = 0;
465 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
466 for (f = p->h[i]; !t->tcm_handle && f;
467 f = f->next) {
468 if (&f->result == r)
469 t->tcm_handle = f->key;
470 }
471 }
472 }
473 pr_debug("handle = %d\n", t->tcm_handle);
474 if (r->res.class)
475 NLA_PUT_U32(skb, TCA_TCINDEX_CLASSID, r->res.classid);
476
477 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
478 goto nla_put_failure;
479 nla_nest_end(skb, nest);
480
481 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
482 goto nla_put_failure;
483 }
484
485 return skb->len;
486
487 nla_put_failure:
488 nlmsg_trim(skb, b);
489 return -1;
490 }
491
492 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
493 .kind = "tcindex",
494 .classify = tcindex_classify,
495 .init = tcindex_init,
496 .destroy = tcindex_destroy,
497 .get = tcindex_get,
498 .put = tcindex_put,
499 .change = tcindex_change,
500 .delete = tcindex_delete,
501 .walk = tcindex_walk,
502 .dump = tcindex_dump,
503 .owner = THIS_MODULE,
504 };
505
506 static int __init init_tcindex(void)
507 {
508 return register_tcf_proto_ops(&cls_tcindex_ops);
509 }
510
511 static void __exit exit_tcindex(void)
512 {
513 unregister_tcf_proto_ops(&cls_tcindex_ops);
514 }
515
516 module_init(init_tcindex)
517 module_exit(exit_tcindex)
518 MODULE_LICENSE("GPL");
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