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 #define PRIV(tp) ((struct tcindex_data *) (tp)->root)
28
29
30 struct tcindex_filter_result {
31 struct tcf_exts exts;
32 struct tcf_result res;
33 };
34
35 struct tcindex_filter {
36 u16 key;
37 struct tcindex_filter_result result;
38 struct tcindex_filter *next;
39 };
40
41
42 struct tcindex_data {
43 struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
44 struct tcindex_filter **h; /* imperfect hash; only used if !perfect;
45 NULL if unused */
46 u16 mask; /* AND key with mask */
47 int shift; /* shift ANDed key to the right */
48 int hash; /* hash table size; 0 if undefined */
49 int alloc_hash; /* allocated size */
50 int fall_through; /* 0: only classify if explicit match */
51 };
52
53 static const struct tcf_ext_map tcindex_ext_map = {
54 .police = TCA_TCINDEX_POLICE,
55 .action = TCA_TCINDEX_ACT
56 };
57
58 static inline int
tcindex_filter_is_set(struct tcindex_filter_result * r)59 tcindex_filter_is_set(struct tcindex_filter_result *r)
60 {
61 return tcf_exts_is_predicative(&r->exts) || r->res.classid;
62 }
63
64 static struct tcindex_filter_result *
tcindex_lookup(struct tcindex_data * p,u16 key)65 tcindex_lookup(struct tcindex_data *p, u16 key)
66 {
67 struct tcindex_filter *f;
68
69 if (p->perfect)
70 return tcindex_filter_is_set(p->perfect + key) ?
71 p->perfect + key : NULL;
72 else if (p->h) {
73 for (f = p->h[key % p->hash]; f; f = f->next)
74 if (f->key == key)
75 return &f->result;
76 }
77
78 return NULL;
79 }
80
81
tcindex_classify(struct sk_buff * skb,const struct tcf_proto * tp,struct tcf_result * res)82 static int tcindex_classify(struct sk_buff *skb, const struct tcf_proto *tp,
83 struct tcf_result *res)
84 {
85 struct tcindex_data *p = PRIV(tp);
86 struct tcindex_filter_result *f;
87 int key = (skb->tc_index & p->mask) >> p->shift;
88
89 pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n",
90 skb, tp, res, p);
91
92 f = tcindex_lookup(p, key);
93 if (!f) {
94 if (!p->fall_through)
95 return -1;
96 res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key);
97 res->class = 0;
98 pr_debug("alg 0x%x\n", res->classid);
99 return 0;
100 }
101 *res = f->res;
102 pr_debug("map 0x%x\n", res->classid);
103
104 return tcf_exts_exec(skb, &f->exts, res);
105 }
106
107
tcindex_get(struct tcf_proto * tp,u32 handle)108 static unsigned long tcindex_get(struct tcf_proto *tp, u32 handle)
109 {
110 struct tcindex_data *p = PRIV(tp);
111 struct tcindex_filter_result *r;
112
113 pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle);
114 if (p->perfect && handle >= p->alloc_hash)
115 return 0;
116 r = tcindex_lookup(p, handle);
117 return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL;
118 }
119
120
tcindex_put(struct tcf_proto * tp,unsigned long f)121 static void tcindex_put(struct tcf_proto *tp, unsigned long f)
122 {
123 pr_debug("tcindex_put(tp %p,f 0x%lx)\n", tp, f);
124 }
125
126
tcindex_init(struct tcf_proto * tp)127 static int tcindex_init(struct tcf_proto *tp)
128 {
129 struct tcindex_data *p;
130
131 pr_debug("tcindex_init(tp %p)\n", tp);
132 p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL);
133 if (!p)
134 return -ENOMEM;
135
136 p->mask = 0xffff;
137 p->hash = DEFAULT_HASH_SIZE;
138 p->fall_through = 1;
139
140 tp->root = p;
141 return 0;
142 }
143
144
145 static int
__tcindex_delete(struct tcf_proto * tp,unsigned long arg,int lock)146 __tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
147 {
148 struct tcindex_data *p = PRIV(tp);
149 struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
150 struct tcindex_filter *f = NULL;
151
152 pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n", tp, arg, p, f);
153 if (p->perfect) {
154 if (!r->res.class)
155 return -ENOENT;
156 } else {
157 int i;
158 struct tcindex_filter **walk = NULL;
159
160 for (i = 0; i < p->hash; i++)
161 for (walk = p->h+i; *walk; walk = &(*walk)->next)
162 if (&(*walk)->result == r)
163 goto found;
164 return -ENOENT;
165
166 found:
167 f = *walk;
168 if (lock)
169 tcf_tree_lock(tp);
170 *walk = f->next;
171 if (lock)
172 tcf_tree_unlock(tp);
173 }
174 tcf_unbind_filter(tp, &r->res);
175 tcf_exts_destroy(tp, &r->exts);
176 kfree(f);
177 return 0;
178 }
179
tcindex_delete(struct tcf_proto * tp,unsigned long arg)180 static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
181 {
182 return __tcindex_delete(tp, arg, 1);
183 }
184
185 static inline int
valid_perfect_hash(struct tcindex_data * p)186 valid_perfect_hash(struct tcindex_data *p)
187 {
188 return p->hash > (p->mask >> p->shift);
189 }
190
191 static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
192 [TCA_TCINDEX_HASH] = { .type = NLA_U32 },
193 [TCA_TCINDEX_MASK] = { .type = NLA_U16 },
194 [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
195 [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
196 [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
197 };
198
199 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)200 tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
201 u32 handle, struct tcindex_data *p,
202 struct tcindex_filter_result *r, struct nlattr **tb,
203 struct nlattr *est)
204 {
205 int err, balloc = 0;
206 struct tcindex_filter_result new_filter_result, *old_r = r;
207 struct tcindex_filter_result cr;
208 struct tcindex_data cp;
209 struct tcindex_filter *f = NULL; /* make gcc behave */
210 struct tcf_exts e;
211
212 err = tcf_exts_validate(net, tp, tb, est, &e, &tcindex_ext_map);
213 if (err < 0)
214 return err;
215
216 memcpy(&cp, p, sizeof(cp));
217 memset(&new_filter_result, 0, sizeof(new_filter_result));
218
219 if (old_r)
220 memcpy(&cr, r, sizeof(cr));
221 else
222 memset(&cr, 0, sizeof(cr));
223
224 if (tb[TCA_TCINDEX_HASH])
225 cp.hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
226
227 if (tb[TCA_TCINDEX_MASK])
228 cp.mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
229
230 if (tb[TCA_TCINDEX_SHIFT])
231 cp.shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
232
233 err = -EBUSY;
234 /* Hash already allocated, make sure that we still meet the
235 * requirements for the allocated hash.
236 */
237 if (cp.perfect) {
238 if (!valid_perfect_hash(&cp) ||
239 cp.hash > cp.alloc_hash)
240 goto errout;
241 } else if (cp.h && cp.hash != cp.alloc_hash)
242 goto errout;
243
244 err = -EINVAL;
245 if (tb[TCA_TCINDEX_FALL_THROUGH])
246 cp.fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
247
248 if (!cp.hash) {
249 /* Hash not specified, use perfect hash if the upper limit
250 * of the hashing index is below the threshold.
251 */
252 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
253 cp.hash = (cp.mask >> cp.shift) + 1;
254 else
255 cp.hash = DEFAULT_HASH_SIZE;
256 }
257
258 if (!cp.perfect && !cp.h)
259 cp.alloc_hash = cp.hash;
260
261 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
262 * but then, we'd fail handles that may become valid after some future
263 * mask change. While this is extremely unlikely to ever matter,
264 * the check below is safer (and also more backwards-compatible).
265 */
266 if (cp.perfect || valid_perfect_hash(&cp))
267 if (handle >= cp.alloc_hash)
268 goto errout;
269
270
271 err = -ENOMEM;
272 if (!cp.perfect && !cp.h) {
273 if (valid_perfect_hash(&cp)) {
274 cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
275 if (!cp.perfect)
276 goto errout;
277 balloc = 1;
278 } else {
279 cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
280 if (!cp.h)
281 goto errout;
282 balloc = 2;
283 }
284 }
285
286 if (cp.perfect)
287 r = cp.perfect + handle;
288 else
289 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
290
291 if (r == &new_filter_result) {
292 f = kzalloc(sizeof(*f), GFP_KERNEL);
293 if (!f)
294 goto errout_alloc;
295 }
296
297 if (tb[TCA_TCINDEX_CLASSID]) {
298 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
299 tcf_bind_filter(tp, &cr.res, base);
300 }
301
302 tcf_exts_change(tp, &cr.exts, &e);
303
304 tcf_tree_lock(tp);
305 if (old_r && old_r != r)
306 memset(old_r, 0, sizeof(*old_r));
307
308 memcpy(p, &cp, sizeof(cp));
309 memcpy(r, &cr, sizeof(cr));
310
311 if (r == &new_filter_result) {
312 struct tcindex_filter **fp;
313
314 f->key = handle;
315 f->result = new_filter_result;
316 f->next = NULL;
317 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
318 /* nothing */;
319 *fp = f;
320 }
321 tcf_tree_unlock(tp);
322
323 return 0;
324
325 errout_alloc:
326 if (balloc == 1)
327 kfree(cp.perfect);
328 else if (balloc == 2)
329 kfree(cp.h);
330 errout:
331 tcf_exts_destroy(tp, &e);
332 return err;
333 }
334
335 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)336 tcindex_change(struct net *net, struct sk_buff *in_skb,
337 struct tcf_proto *tp, unsigned long base, u32 handle,
338 struct nlattr **tca, unsigned long *arg)
339 {
340 struct nlattr *opt = tca[TCA_OPTIONS];
341 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
342 struct tcindex_data *p = PRIV(tp);
343 struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
344 int err;
345
346 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
347 "p %p,r %p,*arg 0x%lx\n",
348 tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
349
350 if (!opt)
351 return 0;
352
353 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
354 if (err < 0)
355 return err;
356
357 return tcindex_set_parms(net, tp, base, handle, p, r, tb,
358 tca[TCA_RATE]);
359 }
360
361
tcindex_walk(struct tcf_proto * tp,struct tcf_walker * walker)362 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
363 {
364 struct tcindex_data *p = PRIV(tp);
365 struct tcindex_filter *f, *next;
366 int i;
367
368 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
369 if (p->perfect) {
370 for (i = 0; i < p->hash; i++) {
371 if (!p->perfect[i].res.class)
372 continue;
373 if (walker->count >= walker->skip) {
374 if (walker->fn(tp,
375 (unsigned long) (p->perfect+i), walker)
376 < 0) {
377 walker->stop = 1;
378 return;
379 }
380 }
381 walker->count++;
382 }
383 }
384 if (!p->h)
385 return;
386 for (i = 0; i < p->hash; i++) {
387 for (f = p->h[i]; f; f = next) {
388 next = f->next;
389 if (walker->count >= walker->skip) {
390 if (walker->fn(tp, (unsigned long) &f->result,
391 walker) < 0) {
392 walker->stop = 1;
393 return;
394 }
395 }
396 walker->count++;
397 }
398 }
399 }
400
401
tcindex_destroy_element(struct tcf_proto * tp,unsigned long arg,struct tcf_walker * walker)402 static int tcindex_destroy_element(struct tcf_proto *tp,
403 unsigned long arg, struct tcf_walker *walker)
404 {
405 return __tcindex_delete(tp, arg, 0);
406 }
407
408
tcindex_destroy(struct tcf_proto * tp)409 static void tcindex_destroy(struct tcf_proto *tp)
410 {
411 struct tcindex_data *p = PRIV(tp);
412 struct tcf_walker walker;
413
414 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
415 walker.count = 0;
416 walker.skip = 0;
417 walker.fn = &tcindex_destroy_element;
418 tcindex_walk(tp, &walker);
419 kfree(p->perfect);
420 kfree(p->h);
421 kfree(p);
422 tp->root = NULL;
423 }
424
425
tcindex_dump(struct tcf_proto * tp,unsigned long fh,struct sk_buff * skb,struct tcmsg * t)426 static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
427 struct sk_buff *skb, struct tcmsg *t)
428 {
429 struct tcindex_data *p = PRIV(tp);
430 struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
431 unsigned char *b = skb_tail_pointer(skb);
432 struct nlattr *nest;
433
434 pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
435 tp, fh, skb, t, p, r, b);
436 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
437
438 nest = nla_nest_start(skb, TCA_OPTIONS);
439 if (nest == NULL)
440 goto nla_put_failure;
441
442 if (!fh) {
443 t->tcm_handle = ~0; /* whatever ... */
444 if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) ||
445 nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) ||
446 nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) ||
447 nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
448 goto nla_put_failure;
449 nla_nest_end(skb, nest);
450 } else {
451 if (p->perfect) {
452 t->tcm_handle = r-p->perfect;
453 } else {
454 struct tcindex_filter *f;
455 int i;
456
457 t->tcm_handle = 0;
458 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
459 for (f = p->h[i]; !t->tcm_handle && f;
460 f = f->next) {
461 if (&f->result == r)
462 t->tcm_handle = f->key;
463 }
464 }
465 }
466 pr_debug("handle = %d\n", t->tcm_handle);
467 if (r->res.class &&
468 nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
469 goto nla_put_failure;
470
471 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
472 goto nla_put_failure;
473 nla_nest_end(skb, nest);
474
475 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
476 goto nla_put_failure;
477 }
478
479 return skb->len;
480
481 nla_put_failure:
482 nlmsg_trim(skb, b);
483 return -1;
484 }
485
486 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
487 .kind = "tcindex",
488 .classify = tcindex_classify,
489 .init = tcindex_init,
490 .destroy = tcindex_destroy,
491 .get = tcindex_get,
492 .put = tcindex_put,
493 .change = tcindex_change,
494 .delete = tcindex_delete,
495 .walk = tcindex_walk,
496 .dump = tcindex_dump,
497 .owner = THIS_MODULE,
498 };
499
init_tcindex(void)500 static int __init init_tcindex(void)
501 {
502 return register_tcf_proto_ops(&cls_tcindex_ops);
503 }
504
exit_tcindex(void)505 static void __exit exit_tcindex(void)
506 {
507 unregister_tcf_proto_ops(&cls_tcindex_ops);
508 }
509
510 module_init(init_tcindex)
511 module_exit(exit_tcindex)
512 MODULE_LICENSE("GPL");
513