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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 #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
 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 *
 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 
 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 
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 
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 
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
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 
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
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
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
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 
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 
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 
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 
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 
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");
513 

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