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TOMOYO Linux Cross Reference
Linux/net/sched/cls_tcindex.c

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  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 void tcindex_filter_result_init(struct tcindex_filter_result *r)
192 {
193         memset(r, 0, sizeof(*r));
194         tcf_exts_init(&r->exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
195 }
196 
197 static int
198 tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
199                   u32 handle, struct tcindex_data *p,
200                   struct tcindex_filter_result *r, struct nlattr **tb,
201                   struct nlattr *est, bool ovr)
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         tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
211         err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
212         if (err < 0)
213                 return err;
214 
215         memcpy(&cp, p, sizeof(cp));
216         tcindex_filter_result_init(&new_filter_result);
217 
218         tcindex_filter_result_init(&cr);
219         if (old_r)
220                 cr.res = r->res;
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                         int i;
273 
274                         cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
275                         if (!cp.perfect)
276                                 goto errout;
277                         for (i = 0; i < cp.hash; i++)
278                                 tcf_exts_init(&cp.perfect[i].exts, TCA_TCINDEX_ACT,
279                                               TCA_TCINDEX_POLICE);
280                         balloc = 1;
281                 } else {
282                         cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
283                         if (!cp.h)
284                                 goto errout;
285                         balloc = 2;
286                 }
287         }
288 
289         if (cp.perfect)
290                 r = cp.perfect + handle;
291         else
292                 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
293 
294         if (r == &new_filter_result) {
295                 f = kzalloc(sizeof(*f), GFP_KERNEL);
296                 if (!f)
297                         goto errout_alloc;
298         }
299 
300         if (tb[TCA_TCINDEX_CLASSID]) {
301                 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
302                 tcf_bind_filter(tp, &cr.res, base);
303         }
304 
305         if (old_r)
306                 tcf_exts_change(tp, &r->exts, &e);
307         else
308                 tcf_exts_change(tp, &cr.exts, &e);
309 
310         tcf_tree_lock(tp);
311         if (old_r && old_r != r)
312                 tcindex_filter_result_init(old_r);
313 
314         memcpy(p, &cp, sizeof(cp));
315         r->res = cr.res;
316 
317         if (r == &new_filter_result) {
318                 struct tcindex_filter **fp;
319 
320                 f->key = handle;
321                 f->result = new_filter_result;
322                 f->next = NULL;
323                 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
324                         /* nothing */;
325                 *fp = f;
326         }
327         tcf_tree_unlock(tp);
328 
329         return 0;
330 
331 errout_alloc:
332         if (balloc == 1)
333                 kfree(cp.perfect);
334         else if (balloc == 2)
335                 kfree(cp.h);
336 errout:
337         tcf_exts_destroy(tp, &e);
338         return err;
339 }
340 
341 static int
342 tcindex_change(struct net *net, struct sk_buff *in_skb,
343                struct tcf_proto *tp, unsigned long base, u32 handle,
344                struct nlattr **tca, unsigned long *arg, bool ovr)
345 {
346         struct nlattr *opt = tca[TCA_OPTIONS];
347         struct nlattr *tb[TCA_TCINDEX_MAX + 1];
348         struct tcindex_data *p = tp->root;
349         struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
350         int err;
351 
352         pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
353             "p %p,r %p,*arg 0x%lx\n",
354             tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
355 
356         if (!opt)
357                 return 0;
358 
359         err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
360         if (err < 0)
361                 return err;
362 
363         return tcindex_set_parms(net, tp, base, handle, p, r, tb,
364                                  tca[TCA_RATE], ovr);
365 }
366 
367 
368 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
369 {
370         struct tcindex_data *p = tp->root;
371         struct tcindex_filter *f, *next;
372         int i;
373 
374         pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
375         if (p->perfect) {
376                 for (i = 0; i < p->hash; i++) {
377                         if (!p->perfect[i].res.class)
378                                 continue;
379                         if (walker->count >= walker->skip) {
380                                 if (walker->fn(tp,
381                                     (unsigned long) (p->perfect+i), walker)
382                                      < 0) {
383                                         walker->stop = 1;
384                                         return;
385                                 }
386                         }
387                         walker->count++;
388                 }
389         }
390         if (!p->h)
391                 return;
392         for (i = 0; i < p->hash; i++) {
393                 for (f = p->h[i]; f; f = next) {
394                         next = f->next;
395                         if (walker->count >= walker->skip) {
396                                 if (walker->fn(tp, (unsigned long) &f->result,
397                                     walker) < 0) {
398                                         walker->stop = 1;
399                                         return;
400                                 }
401                         }
402                         walker->count++;
403                 }
404         }
405 }
406 
407 
408 static int tcindex_destroy_element(struct tcf_proto *tp,
409     unsigned long arg, struct tcf_walker *walker)
410 {
411         return __tcindex_delete(tp, arg, 0);
412 }
413 
414 
415 static void tcindex_destroy(struct tcf_proto *tp)
416 {
417         struct tcindex_data *p = tp->root;
418         struct tcf_walker walker;
419 
420         pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
421         walker.count = 0;
422         walker.skip = 0;
423         walker.fn = tcindex_destroy_element;
424         tcindex_walk(tp, &walker);
425         kfree(p->perfect);
426         kfree(p->h);
427         kfree(p);
428         tp->root = NULL;
429 }
430 
431 
432 static int tcindex_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
433     struct sk_buff *skb, struct tcmsg *t)
434 {
435         struct tcindex_data *p = tp->root;
436         struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
437         unsigned char *b = skb_tail_pointer(skb);
438         struct nlattr *nest;
439 
440         pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
441                  tp, fh, skb, t, p, r, b);
442         pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
443 
444         nest = nla_nest_start(skb, TCA_OPTIONS);
445         if (nest == NULL)
446                 goto nla_put_failure;
447 
448         if (!fh) {
449                 t->tcm_handle = ~0; /* whatever ... */
450                 if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) ||
451                     nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) ||
452                     nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) ||
453                     nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
454                         goto nla_put_failure;
455                 nla_nest_end(skb, nest);
456         } else {
457                 if (p->perfect) {
458                         t->tcm_handle = r-p->perfect;
459                 } else {
460                         struct tcindex_filter *f;
461                         int i;
462 
463                         t->tcm_handle = 0;
464                         for (i = 0; !t->tcm_handle && i < p->hash; i++) {
465                                 for (f = p->h[i]; !t->tcm_handle && f;
466                                      f = f->next) {
467                                         if (&f->result == r)
468                                                 t->tcm_handle = f->key;
469                                 }
470                         }
471                 }
472                 pr_debug("handle = %d\n", t->tcm_handle);
473                 if (r->res.class &&
474                     nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
475                         goto nla_put_failure;
476 
477                 if (tcf_exts_dump(skb, &r->exts) < 0)
478                         goto nla_put_failure;
479                 nla_nest_end(skb, nest);
480 
481                 if (tcf_exts_dump_stats(skb, &r->exts) < 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");
519 

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