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Linux 2.6.33-rc8
[linux-2.6/lguest.git] / net / sched / cls_tcindex.c
blobe806f2314b5e24281dd4bfbe3f442d1c1ee51d41
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 * Passing parameters to the root seems to be done more awkwardly than really
18 * necessary. At least, u32 doesn't seem to use such dirty hacks. To be
19 * verified. FIXME.
20 */
21
22 #define PERFECT_HASH_THRESHOLD 64 /* use perfect hash if not bigger */
23 #define DEFAULT_HASH_SIZE 64 /* optimized for diffserv */
24
25
26 #define PRIV(tp) ((struct tcindex_data *) (tp)->root)
27
28
29 struct tcindex_filter_result {
30 struct tcf_exts exts;
31 struct tcf_result res;
32 };
33
34 struct tcindex_filter {
35 u16 key;
36 struct tcindex_filter_result result;
37 struct tcindex_filter *next;
38 };
39
40
41 struct tcindex_data {
42 struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
43 struct tcindex_filter **h; /* imperfect hash; only used if !perfect;
44 NULL if unused */
45 u16 mask; /* AND key with mask */
46 int shift; /* shift ANDed key to the right */
47 int hash; /* hash table size; 0 if undefined */
48 int alloc_hash; /* allocated size */
49 int fall_through; /* 0: only classify if explicit match */
50 };
51
52 static const struct tcf_ext_map tcindex_ext_map = {
53 .police = TCA_TCINDEX_POLICE,
54 .action = TCA_TCINDEX_ACT
55 };
56
57 static inline int
58 tcindex_filter_is_set(struct tcindex_filter_result *r)
59 {
60 return tcf_exts_is_predicative(&r->exts) || r->res.classid;
61 }
62
63 static struct tcindex_filter_result *
64 tcindex_lookup(struct tcindex_data *p, u16 key)
65 {
66 struct tcindex_filter *f;
67
68 if (p->perfect)
69 return tcindex_filter_is_set(p->perfect + key) ?
70 p->perfect + key : NULL;
71 else if (p->h) {
72 for (f = p->h[key % p->hash]; f; f = f->next)
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, struct tcf_proto *tp,
82 struct tcf_result *res)
83 {
84 struct tcindex_data *p = PRIV(tp);
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 = PRIV(tp);
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 tp->root = p;
140 return 0;
141 }
142
143
144 static int
145 __tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
146 {
147 struct tcindex_data *p = PRIV(tp);
148 struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
149 struct tcindex_filter *f = NULL;
150
151 pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n", tp, arg, p, f);
152 if (p->perfect) {
153 if (!r->res.class)
154 return -ENOENT;
155 } else {
156 int i;
157 struct tcindex_filter **walk = NULL;
158
159 for (i = 0; i < p->hash; i++)
160 for (walk = p->h+i; *walk; walk = &(*walk)->next)
161 if (&(*walk)->result == r)
162 goto found;
163 return -ENOENT;
164
165 found:
166 f = *walk;
167 if (lock)
168 tcf_tree_lock(tp);
169 *walk = f->next;
170 if (lock)
171 tcf_tree_unlock(tp);
172 }
173 tcf_unbind_filter(tp, &r->res);
174 tcf_exts_destroy(tp, &r->exts);
175 kfree(f);
176 return 0;
177 }
178
179 static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
180 {
181 return __tcindex_delete(tp, arg, 1);
182 }
183
184 static inline int
185 valid_perfect_hash(struct tcindex_data *p)
186 {
187 return p->hash > (p->mask >> p->shift);
188 }
189
190 static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
191 [TCA_TCINDEX_HASH] = { .type = NLA_U32 },
192 [TCA_TCINDEX_MASK] = { .type = NLA_U16 },
193 [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
194 [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
195 [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
196 };
197
198 static int
199 tcindex_set_parms(struct tcf_proto *tp, unsigned long base, u32 handle,
200 struct tcindex_data *p, struct tcindex_filter_result *r,
201 struct nlattr **tb, struct nlattr *est)
202 {
203 int err, balloc = 0;
204 struct tcindex_filter_result new_filter_result, *old_r = r;
205 struct tcindex_filter_result cr;
206 struct tcindex_data cp;
207 struct tcindex_filter *f = NULL; /* make gcc behave */
208 struct tcf_exts e;
209
210 err = tcf_exts_validate(tp, tb, est, &e, &tcindex_ext_map);
211 if (err < 0)
212 return err;
213
214 memcpy(&cp, p, sizeof(cp));
215 memset(&new_filter_result, 0, sizeof(new_filter_result));
216
217 if (old_r)
218 memcpy(&cr, r, sizeof(cr));
219 else
220 memset(&cr, 0, sizeof(cr));
221
222 if (tb[TCA_TCINDEX_HASH])
223 cp.hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
224
225 if (tb[TCA_TCINDEX_MASK])
226 cp.mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
227
228 if (tb[TCA_TCINDEX_SHIFT])
229 cp.shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
230
231 err = -EBUSY;
232 /* Hash already allocated, make sure that we still meet the
233 * requirements for the allocated hash.
234 */
235 if (cp.perfect) {
236 if (!valid_perfect_hash(&cp) ||
237 cp.hash > cp.alloc_hash)
238 goto errout;
239 } else if (cp.h && cp.hash != cp.alloc_hash)
240 goto errout;
241
242 err = -EINVAL;
243 if (tb[TCA_TCINDEX_FALL_THROUGH])
244 cp.fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
245
246 if (!cp.hash) {
247 /* Hash not specified, use perfect hash if the upper limit
248 * of the hashing index is below the threshold.
249 */
250 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
251 cp.hash = (cp.mask >> cp.shift)+1;
252 else
253 cp.hash = DEFAULT_HASH_SIZE;
254 }
255
256 if (!cp.perfect && !cp.h)
257 cp.alloc_hash = cp.hash;
258
259 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
260 * but then, we'd fail handles that may become valid after some future
261 * mask change. While this is extremely unlikely to ever matter,
262 * the check below is safer (and also more backwards-compatible).
263 */
264 if (cp.perfect || valid_perfect_hash(&cp))
265 if (handle >= cp.alloc_hash)
266 goto errout;
267
268
269 err = -ENOMEM;
270 if (!cp.perfect && !cp.h) {
271 if (valid_perfect_hash(&cp)) {
272 cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
273 if (!cp.perfect)
274 goto errout;
275 balloc = 1;
276 } else {
277 cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
278 if (!cp.h)
279 goto errout;
280 balloc = 2;
281 }
282 }
283
284 if (cp.perfect)
285 r = cp.perfect + handle;
286 else
287 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
288
289 if (r == &new_filter_result) {
290 f = kzalloc(sizeof(*f), GFP_KERNEL);
291 if (!f)
292 goto errout_alloc;
293 }
294
295 if (tb[TCA_TCINDEX_CLASSID]) {
296 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
297 tcf_bind_filter(tp, &cr.res, base);
298 }
299
300 tcf_exts_change(tp, &cr.exts, &e);
301
302 tcf_tree_lock(tp);
303 if (old_r && old_r != r)
304 memset(old_r, 0, sizeof(*old_r));
305
306 memcpy(p, &cp, sizeof(cp));
307 memcpy(r, &cr, sizeof(cr));
308
309 if (r == &new_filter_result) {
310 struct tcindex_filter **fp;
311
312 f->key = handle;
313 f->result = new_filter_result;
314 f->next = NULL;
315 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
316 /* nothing */;
317 *fp = f;
318 }
319 tcf_tree_unlock(tp);
320
321 return 0;
322
323 errout_alloc:
324 if (balloc == 1)
325 kfree(cp.perfect);
326 else if (balloc == 2)
327 kfree(cp.h);
328 errout:
329 tcf_exts_destroy(tp, &e);
330 return err;
331 }
332
333 static int
334 tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
335 struct nlattr **tca, unsigned long *arg)
336 {
337 struct nlattr *opt = tca[TCA_OPTIONS];
338 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
339 struct tcindex_data *p = PRIV(tp);
340 struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
341 int err;
342
343 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
344 "p %p,r %p,*arg 0x%lx\n",
345 tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
346
347 if (!opt)
348 return 0;
349
350 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
351 if (err < 0)
352 return err;
353
354 return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE]);
355 }
356
357
358 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
359 {
360 struct tcindex_data *p = PRIV(tp);
361 struct tcindex_filter *f, *next;
362 int i;
363
364 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
365 if (p->perfect) {
366 for (i = 0; i < p->hash; i++) {
367 if (!p->perfect[i].res.class)
368 continue;
369 if (walker->count >= walker->skip) {
370 if (walker->fn(tp,
371 (unsigned long) (p->perfect+i), walker)
372 < 0) {
373 walker->stop = 1;
374 return;
375 }
376 }
377 walker->count++;
378 }
379 }
380 if (!p->h)
381 return;
382 for (i = 0; i < p->hash; i++) {
383 for (f = p->h[i]; f; f = next) {
384 next = f->next;
385 if (walker->count >= walker->skip) {
386 if (walker->fn(tp, (unsigned long) &f->result,
387 walker) < 0) {
388 walker->stop = 1;
389 return;
390 }
391 }
392 walker->count++;
393 }
394 }
395 }
396
397
398 static int tcindex_destroy_element(struct tcf_proto *tp,
399 unsigned long arg, struct tcf_walker *walker)
400 {
401 return __tcindex_delete(tp, arg, 0);
402 }
403
404
405 static void tcindex_destroy(struct tcf_proto *tp)
406 {
407 struct tcindex_data *p = PRIV(tp);
408 struct tcf_walker walker;
409
410 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
411 walker.count = 0;
412 walker.skip = 0;
413 walker.fn = &tcindex_destroy_element;
414 tcindex_walk(tp, &walker);
415 kfree(p->perfect);
416 kfree(p->h);
417 kfree(p);
418 tp->root = NULL;
419 }
420
421
422 static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
423 struct sk_buff *skb, struct tcmsg *t)
424 {
425 struct tcindex_data *p = PRIV(tp);
426 struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
427 unsigned char *b = skb_tail_pointer(skb);
428 struct nlattr *nest;
429
430 pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
431 tp, fh, skb, t, p, r, b);
432 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
433
434 nest = nla_nest_start(skb, TCA_OPTIONS);
435 if (nest == NULL)
436 goto nla_put_failure;
437
438 if (!fh) {
439 t->tcm_handle = ~0; /* whatever ... */
440 NLA_PUT_U32(skb, TCA_TCINDEX_HASH, p->hash);
441 NLA_PUT_U16(skb, TCA_TCINDEX_MASK, p->mask);
442 NLA_PUT_U32(skb, TCA_TCINDEX_SHIFT, p->shift);
443 NLA_PUT_U32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through);
444 nla_nest_end(skb, nest);
445 } else {
446 if (p->perfect) {
447 t->tcm_handle = r-p->perfect;
448 } else {
449 struct tcindex_filter *f;
450 int i;
451
452 t->tcm_handle = 0;
453 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
454 for (f = p->h[i]; !t->tcm_handle && f;
455 f = f->next) {
456 if (&f->result == r)
457 t->tcm_handle = f->key;
458 }
459 }
460 }
461 pr_debug("handle = %d\n", t->tcm_handle);
462 if (r->res.class)
463 NLA_PUT_U32(skb, TCA_TCINDEX_CLASSID, r->res.classid);
464
465 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
466 goto nla_put_failure;
467 nla_nest_end(skb, nest);
468
469 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
470 goto nla_put_failure;
471 }
472
473 return skb->len;
474
475 nla_put_failure:
476 nlmsg_trim(skb, b);
477 return -1;
478 }
479
480 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
481 .kind = "tcindex",
482 .classify = tcindex_classify,
483 .init = tcindex_init,
484 .destroy = tcindex_destroy,
485 .get = tcindex_get,
486 .put = tcindex_put,
487 .change = tcindex_change,
488 .delete = tcindex_delete,
489 .walk = tcindex_walk,
490 .dump = tcindex_dump,
491 .owner = THIS_MODULE,
492 };
493
494 static int __init init_tcindex(void)
495 {
496 return register_tcf_proto_ops(&cls_tcindex_ops);
497 }
498
499 static void __exit exit_tcindex(void)
500 {
501 unregister_tcf_proto_ops(&cls_tcindex_ops);
502 }
503
504 module_init(init_tcindex)
505 module_exit(exit_tcindex)
506 MODULE_LICENSE("GPL");
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