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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / net / sched / cls_tcindex.c
blob7a7bff5ded2487801e3c34941c1e12b8d77926fc
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 const 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 const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
197 [TCA_TCINDEX_HASH] = { .type = NLA_U32 },
198 [TCA_TCINDEX_MASK] = { .type = NLA_U16 },
199 [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
200 [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
201 [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
202 };
203
204 static int
205 tcindex_set_parms(struct tcf_proto *tp, unsigned long base, u32 handle,
206 struct tcindex_data *p, struct tcindex_filter_result *r,
207 struct nlattr **tb, struct nlattr *est)
208 {
209 int err, balloc = 0;
210 struct tcindex_filter_result new_filter_result, *old_r = r;
211 struct tcindex_filter_result cr;
212 struct tcindex_data cp;
213 struct tcindex_filter *f = NULL; /* make gcc behave */
214 struct tcf_exts e;
215
216 err = tcf_exts_validate(tp, tb, est, &e, &tcindex_ext_map);
217 if (err < 0)
218 return err;
219
220 memcpy(&cp, p, sizeof(cp));
221 memset(&new_filter_result, 0, sizeof(new_filter_result));
222
223 if (old_r)
224 memcpy(&cr, r, sizeof(cr));
225 else
226 memset(&cr, 0, sizeof(cr));
227
228 if (tb[TCA_TCINDEX_HASH])
229 cp.hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
230
231 if (tb[TCA_TCINDEX_MASK])
232 cp.mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
233
234 if (tb[TCA_TCINDEX_SHIFT])
235 cp.shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
236
237 err = -EBUSY;
238 /* Hash already allocated, make sure that we still meet the
239 * requirements for the allocated hash.
240 */
241 if (cp.perfect) {
242 if (!valid_perfect_hash(&cp) ||
243 cp.hash > cp.alloc_hash)
244 goto errout;
245 } else if (cp.h && cp.hash != cp.alloc_hash)
246 goto errout;
247
248 err = -EINVAL;
249 if (tb[TCA_TCINDEX_FALL_THROUGH])
250 cp.fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
251
252 if (!cp.hash) {
253 /* Hash not specified, use perfect hash if the upper limit
254 * of the hashing index is below the threshold.
255 */
256 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
257 cp.hash = (cp.mask >> cp.shift)+1;
258 else
259 cp.hash = DEFAULT_HASH_SIZE;
260 }
261
262 if (!cp.perfect && !cp.h)
263 cp.alloc_hash = cp.hash;
264
265 /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
266 * but then, we'd fail handles that may become valid after some future
267 * mask change. While this is extremely unlikely to ever matter,
268 * the check below is safer (and also more backwards-compatible).
269 */
270 if (cp.perfect || valid_perfect_hash(&cp))
271 if (handle >= cp.alloc_hash)
272 goto errout;
273
274
275 err = -ENOMEM;
276 if (!cp.perfect && !cp.h) {
277 if (valid_perfect_hash(&cp)) {
278 cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
279 if (!cp.perfect)
280 goto errout;
281 balloc = 1;
282 } else {
283 cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
284 if (!cp.h)
285 goto errout;
286 balloc = 2;
287 }
288 }
289
290 if (cp.perfect)
291 r = cp.perfect + handle;
292 else
293 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
294
295 if (r == &new_filter_result) {
296 f = kzalloc(sizeof(*f), GFP_KERNEL);
297 if (!f)
298 goto errout_alloc;
299 }
300
301 if (tb[TCA_TCINDEX_CLASSID]) {
302 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
303 tcf_bind_filter(tp, &cr.res, base);
304 }
305
306 tcf_exts_change(tp, &cr.exts, &e);
307
308 tcf_tree_lock(tp);
309 if (old_r && old_r != r)
310 memset(old_r, 0, sizeof(*old_r));
311
312 memcpy(p, &cp, sizeof(cp));
313 memcpy(r, &cr, sizeof(cr));
314
315 if (r == &new_filter_result) {
316 struct tcindex_filter **fp;
317
318 f->key = handle;
319 f->result = new_filter_result;
320 f->next = NULL;
321 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
322 /* nothing */;
323 *fp = f;
324 }
325 tcf_tree_unlock(tp);
326
327 return 0;
328
329 errout_alloc:
330 if (balloc == 1)
331 kfree(cp.perfect);
332 else if (balloc == 2)
333 kfree(cp.h);
334 errout:
335 tcf_exts_destroy(tp, &e);
336 return err;
337 }
338
339 static int
340 tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
341 struct nlattr **tca, unsigned long *arg)
342 {
343 struct nlattr *opt = tca[TCA_OPTIONS];
344 struct nlattr *tb[TCA_TCINDEX_MAX + 1];
345 struct tcindex_data *p = PRIV(tp);
346 struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
347 int err;
348
349 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
350 "p %p,r %p,*arg 0x%lx\n",
351 tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
352
353 if (!opt)
354 return 0;
355
356 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
357 if (err < 0)
358 return err;
359
360 return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE]);
361 }
362
363
364 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
365 {
366 struct tcindex_data *p = PRIV(tp);
367 struct tcindex_filter *f, *next;
368 int i;
369
370 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
371 if (p->perfect) {
372 for (i = 0; i < p->hash; i++) {
373 if (!p->perfect[i].res.class)
374 continue;
375 if (walker->count >= walker->skip) {
376 if (walker->fn(tp,
377 (unsigned long) (p->perfect+i), walker)
378 < 0) {
379 walker->stop = 1;
380 return;
381 }
382 }
383 walker->count++;
384 }
385 }
386 if (!p->h)
387 return;
388 for (i = 0; i < p->hash; i++) {
389 for (f = p->h[i]; f; f = next) {
390 next = f->next;
391 if (walker->count >= walker->skip) {
392 if (walker->fn(tp, (unsigned long) &f->result,
393 walker) < 0) {
394 walker->stop = 1;
395 return;
396 }
397 }
398 walker->count++;
399 }
400 }
401 }
402
403
404 static int tcindex_destroy_element(struct tcf_proto *tp,
405 unsigned long arg, struct tcf_walker *walker)
406 {
407 return __tcindex_delete(tp, arg, 0);
408 }
409
410
411 static void tcindex_destroy(struct tcf_proto *tp)
412 {
413 struct tcindex_data *p = PRIV(tp);
414 struct tcf_walker walker;
415
416 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
417 walker.count = 0;
418 walker.skip = 0;
419 walker.fn = &tcindex_destroy_element;
420 tcindex_walk(tp, &walker);
421 kfree(p->perfect);
422 kfree(p->h);
423 kfree(p);
424 tp->root = NULL;
425 }
426
427
428 static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
429 struct sk_buff *skb, struct tcmsg *t)
430 {
431 struct tcindex_data *p = PRIV(tp);
432 struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
433 unsigned char *b = skb_tail_pointer(skb);
434 struct nlattr *nest;
435
436 pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
437 tp, fh, skb, t, p, r, b);
438 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
439
440 nest = nla_nest_start(skb, TCA_OPTIONS);
441 if (nest == NULL)
442 goto nla_put_failure;
443
444 if (!fh) {
445 t->tcm_handle = ~0; /* whatever ... */
446 NLA_PUT_U32(skb, TCA_TCINDEX_HASH, p->hash);
447 NLA_PUT_U16(skb, TCA_TCINDEX_MASK, p->mask);
448 NLA_PUT_U32(skb, TCA_TCINDEX_SHIFT, p->shift);
449 NLA_PUT_U32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through);
450 nla_nest_end(skb, nest);
451 } else {
452 if (p->perfect) {
453 t->tcm_handle = r-p->perfect;
454 } else {
455 struct tcindex_filter *f;
456 int i;
457
458 t->tcm_handle = 0;
459 for (i = 0; !t->tcm_handle && i < p->hash; i++) {
460 for (f = p->h[i]; !t->tcm_handle && f;
461 f = f->next) {
462 if (&f->result == r)
463 t->tcm_handle = f->key;
464 }
465 }
466 }
467 pr_debug("handle = %d\n", t->tcm_handle);
468 if (r->res.class)
469 NLA_PUT_U32(skb, TCA_TCINDEX_CLASSID, r->res.classid);
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
500 static int __init init_tcindex(void)
501 {
502 return register_tcf_proto_ops(&cls_tcindex_ops);
503 }
504
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");
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