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sched, cls: check if we could overwrite actions when changing a filter
[linux/fpc-iii.git] / net / sched / cls_tcindex.c
blobd11d0a4fbe34f6af8390e9752468b2446079733a
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 *next;
36 };
37
38
39 struct tcindex_data {
40 struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
41 struct tcindex_filter **h; /* imperfect hash; only used if !perfect;
42 NULL if unused */
43 u16 mask; /* AND key with mask */
44 int shift; /* shift ANDed key to the right */
45 int hash; /* hash table size; 0 if undefined */
46 int alloc_hash; /* allocated size */
47 int fall_through; /* 0: only classify if explicit match */
48 };
49
50 static inline int
51 tcindex_filter_is_set(struct tcindex_filter_result *r)
52 {
53 return tcf_exts_is_predicative(&r->exts) || r->res.classid;
54 }
55
56 static struct tcindex_filter_result *
57 tcindex_lookup(struct tcindex_data *p, u16 key)
58 {
59 struct tcindex_filter *f;
60
61 if (p->perfect)
62 return tcindex_filter_is_set(p->perfect + key) ?
63 p->perfect + key : NULL;
64 else if (p->h) {
65 for (f = p->h[key % p->hash]; f; f = f->next)
66 if (f->key == key)
67 return &f->result;
68 }
69
70 return NULL;
71 }
72
73
74 static int tcindex_classify(struct sk_buff *skb, const struct tcf_proto *tp,
75 struct tcf_result *res)
76 {
77 struct tcindex_data *p = tp->root;
78 struct tcindex_filter_result *f;
79 int key = (skb->tc_index & p->mask) >> p->shift;
80
81 pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n",
82 skb, tp, res, p);
83
84 f = tcindex_lookup(p, key);
85 if (!f) {
86 if (!p->fall_through)
87 return -1;
88 res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key);
89 res->class = 0;
90 pr_debug("alg 0x%x\n", res->classid);
91 return 0;
92 }
93 *res = f->res;
94 pr_debug("map 0x%x\n", res->classid);
95
96 return tcf_exts_exec(skb, &f->exts, res);
97 }
98
99
100 static unsigned long tcindex_get(struct tcf_proto *tp, u32 handle)
101 {
102 struct tcindex_data *p = tp->root;
103 struct tcindex_filter_result *r;
104
105 pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle);
106 if (p->perfect && handle >= p->alloc_hash)
107 return 0;
108 r = tcindex_lookup(p, handle);
109 return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL;
110 }
111
112
113 static void tcindex_put(struct tcf_proto *tp, unsigned long f)
114 {
115 pr_debug("tcindex_put(tp %p,f 0x%lx)\n", tp, f);
116 }
117
118
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 tp->root = p;
133 return 0;
134 }
135
136
137 static int
138 __tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
139 {
140 struct tcindex_data *p = tp->root;
141 struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
142 struct tcindex_filter *f = NULL;
143
144 pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n", tp, arg, p, f);
145 if (p->perfect) {
146 if (!r->res.class)
147 return -ENOENT;
148 } else {
149 int i;
150 struct tcindex_filter **walk = NULL;
151
152 for (i = 0; i < p->hash; i++)
153 for (walk = p->h+i; *walk; walk = &(*walk)->next)
154 if (&(*walk)->result == r)
155 goto found;
156 return -ENOENT;
157
158 found:
159 f = *walk;
160 if (lock)
161 tcf_tree_lock(tp);
162 *walk = f->next;
163 if (lock)
164 tcf_tree_unlock(tp);
165 }
166 tcf_unbind_filter(tp, &r->res);
167 tcf_exts_destroy(tp, &r->exts);
168 kfree(f);
169 return 0;
170 }
171
172 static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
173 {
174 return __tcindex_delete(tp, arg, 1);
175 }
176
177 static inline int
178 valid_perfect_hash(struct tcindex_data *p)
179 {
180 return p->hash > (p->mask >> p->shift);
181 }
182
183 static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
184 [TCA_TCINDEX_HASH] = { .type = NLA_U32 },
185 [TCA_TCINDEX_MASK] = { .type = NLA_U16 },
186 [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
187 [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
188 [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
189 };
190
191 static int
192 tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
193 u32 handle, struct tcindex_data *p,
194 struct tcindex_filter_result *r, struct nlattr **tb,
195 struct nlattr *est, bool ovr)
196 {
197 int err, balloc = 0;
198 struct tcindex_filter_result new_filter_result, *old_r = r;
199 struct tcindex_filter_result cr;
200 struct tcindex_data cp;
201 struct tcindex_filter *f = NULL; /* make gcc behave */
202 struct tcf_exts e;
203
204 tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
205 err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
206 if (err < 0)
207 return err;
208
209 memcpy(&cp, p, sizeof(cp));
210 memset(&new_filter_result, 0, sizeof(new_filter_result));
211 tcf_exts_init(&new_filter_result.exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
212
213 if (old_r)
214 memcpy(&cr, r, sizeof(cr));
215 else {
216 memset(&cr, 0, sizeof(cr));
217 tcf_exts_init(&cr.exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
218 }
219
220 if (tb[TCA_TCINDEX_HASH])
221 cp.hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
222
223 if (tb[TCA_TCINDEX_MASK])
224 cp.mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
225
226 if (tb[TCA_TCINDEX_SHIFT])
227 cp.shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
228
229 err = -EBUSY;
230 /* Hash already allocated, make sure that we still meet the
231 * requirements for the allocated hash.
232 */
233 if (cp.perfect) {
234 if (!valid_perfect_hash(&cp) ||
235 cp.hash > cp.alloc_hash)
236 goto errout;
237 } else if (cp.h && cp.hash != cp.alloc_hash)
238 goto errout;
239
240 err = -EINVAL;
241 if (tb[TCA_TCINDEX_FALL_THROUGH])
242 cp.fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
243
244 if (!cp.hash) {
245 /* Hash not specified, use perfect hash if the upper limit
246 * of the hashing index is below the threshold.
247 */
248 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
249 cp.hash = (cp.mask >> cp.shift) + 1;
250 else
251 cp.hash = DEFAULT_HASH_SIZE;
252 }
253
254 if (!cp.perfect && !cp.h)
255 cp.alloc_hash = cp.hash;
256
257 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
258 * but then, we'd fail handles that may become valid after some future
259 * mask change. While this is extremely unlikely to ever matter,
260 * the check below is safer (and also more backwards-compatible).
261 */
262 if (cp.perfect || valid_perfect_hash(&cp))
263 if (handle >= cp.alloc_hash)
264 goto errout;
265
266
267 err = -ENOMEM;
268 if (!cp.perfect && !cp.h) {
269 if (valid_perfect_hash(&cp)) {
270 cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
271 if (!cp.perfect)
272 goto errout;
273 balloc = 1;
274 } else {
275 cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
276 if (!cp.h)
277 goto errout;
278 balloc = 2;
279 }
280 }
281
282 if (cp.perfect)
283 r = cp.perfect + handle;
284 else
285 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
286
287 if (r == &new_filter_result) {
288 f = kzalloc(sizeof(*f), GFP_KERNEL);
289 if (!f)
290 goto errout_alloc;
291 }
292
293 if (tb[TCA_TCINDEX_CLASSID]) {
294 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
295 tcf_bind_filter(tp, &cr.res, base);
296 }
297
298 tcf_exts_change(tp, &cr.exts, &e);
299
300 tcf_tree_lock(tp);
301 if (old_r && old_r != r)
302 memset(old_r, 0, sizeof(*old_r));
303
304 memcpy(p, &cp, sizeof(cp));
305 memcpy(r, &cr, sizeof(cr));
306
307 if (r == &new_filter_result) {
308 struct tcindex_filter **fp;
309
310 f->key = handle;
311 f->result = new_filter_result;
312 f->next = NULL;
313 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
314 /* nothing */;
315 *fp = f;
316 }
317 tcf_tree_unlock(tp);
318
319 return 0;
320
321 errout_alloc:
322 if (balloc == 1)
323 kfree(cp.perfect);
324 else if (balloc == 2)
325 kfree(cp.h);
326 errout:
327 tcf_exts_destroy(tp, &e);
328 return err;
329 }
330
331 static int
332 tcindex_change(struct net *net, struct sk_buff *in_skb,
333 struct tcf_proto *tp, unsigned long base, u32 handle,
334 struct nlattr **tca, unsigned long *arg, bool ovr)
335 {
336 struct nlattr *opt = tca[TCA_OPTIONS];
337 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
338 struct tcindex_data *p = tp->root;
339 struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
340 int err;
341
342 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
343 "p %p,r %p,*arg 0x%lx\n",
344 tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
345
346 if (!opt)
347 return 0;
348
349 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
350 if (err < 0)
351 return err;
352
353 return tcindex_set_parms(net, tp, base, handle, p, r, tb,
354 tca[TCA_RATE], ovr);
355 }
356
357
358 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
359 {
360 struct tcindex_data *p = tp->root;
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 = tp->root;
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 net *net, struct tcf_proto *tp, unsigned long fh,
423 struct sk_buff *skb, struct tcmsg *t)
424 {
425 struct tcindex_data *p = tp->root;
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 if (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 goto nla_put_failure;
445 nla_nest_end(skb, nest);
446 } else {
447 if (p->perfect) {
448 t->tcm_handle = r-p->perfect;
449 } else {
450 struct tcindex_filter *f;
451 int i;
452
453 t->tcm_handle = 0;
454 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
455 for (f = p->h[i]; !t->tcm_handle && f;
456 f = f->next) {
457 if (&f->result == r)
458 t->tcm_handle = f->key;
459 }
460 }
461 }
462 pr_debug("handle = %d\n", t->tcm_handle);
463 if (r->res.class &&
464 nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
465 goto nla_put_failure;
466
467 if (tcf_exts_dump(skb, &r->exts) < 0)
468 goto nla_put_failure;
469 nla_nest_end(skb, nest);
470
471 if (tcf_exts_dump_stats(skb, &r->exts) < 0)
472 goto nla_put_failure;
473 }
474
475 return skb->len;
476
477 nla_put_failure:
478 nlmsg_trim(skb, b);
479 return -1;
480 }
481
482 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
483 .kind = "tcindex",
484 .classify = tcindex_classify,
485 .init = tcindex_init,
486 .destroy = tcindex_destroy,
487 .get = tcindex_get,
488 .put = tcindex_put,
489 .change = tcindex_change,
490 .delete = tcindex_delete,
491 .walk = tcindex_walk,
492 .dump = tcindex_dump,
493 .owner = THIS_MODULE,
494 };
495
496 static int __init init_tcindex(void)
497 {
498 return register_tcf_proto_ops(&cls_tcindex_ops);
499 }
500
501 static void __exit exit_tcindex(void)
502 {
503 unregister_tcf_proto_ops(&cls_tcindex_ops);
504 }
505
506 module_init(init_tcindex)
507 module_exit(exit_tcindex)
508 MODULE_LICENSE("GPL");
Linux with added FPC-III support