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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 <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 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 int
 197 tcindex_set_parms(struct tcf_proto *tp, unsigned long base, u32 handle,
 198                   struct tcindex_data *p, struct tcindex_filter_result *r,
 199                   struct nlattr **tb, struct nlattr *est)
 200 {
 201         int err, balloc = 0;
 202         struct tcindex_filter_result new_filter_result, *old_r = r;
 203         struct tcindex_filter_result cr;
 204         struct tcindex_data cp;
 205         struct tcindex_filter *f = NULL; /* make gcc behave */
 206         struct tcf_exts e;
 207
 208         err = tcf_exts_validate(tp, tb, est, &e, &tcindex_ext_map);
 209         if (err < 0)
 210                 return err;
 211
 212         memcpy(&cp, p, sizeof(cp));
 213         memset(&new_filter_result, 0, sizeof(new_filter_result));
 214
 215         if (old_r)
 216                 memcpy(&cr, r, sizeof(cr));
 217         else
 218                 memset(&cr, 0, sizeof(cr));
 219
 220         err = -EINVAL;
 221         if (tb[TCA_TCINDEX_HASH]) {
 222                 if (nla_len(tb[TCA_TCINDEX_HASH]) < sizeof(u32))
 223                         goto errout;
 224                 cp.hash = *(u32 *) nla_data(tb[TCA_TCINDEX_HASH]);
 225         }
 226
 227         if (tb[TCA_TCINDEX_MASK]) {
 228                 if (nla_len(tb[TCA_TCINDEX_MASK]) < sizeof(u16))
 229                         goto errout;
 230                 cp.mask = *(u16 *) nla_data(tb[TCA_TCINDEX_MASK]);
 231         }
 232
 233         if (tb[TCA_TCINDEX_SHIFT]) {
 234                 if (nla_len(tb[TCA_TCINDEX_SHIFT]) < sizeof(int))
 235                         goto errout;
 236                 cp.shift = *(int *) nla_data(tb[TCA_TCINDEX_SHIFT]);
 237         }
 238
 239         err = -EBUSY;
 240         /* Hash already allocated, make sure that we still meet the
 241          * requirements for the allocated hash.
 242          */
 243         if (cp.perfect) {
 244                 if (!valid_perfect_hash(&cp) ||
 245                     cp.hash > cp.alloc_hash)
 246                         goto errout;
 247         } else if (cp.h && cp.hash != cp.alloc_hash)
 248                 goto errout;
 249
 250         err = -EINVAL;
 251         if (tb[TCA_TCINDEX_FALL_THROUGH]) {
 252                 if (nla_len(tb[TCA_TCINDEX_FALL_THROUGH]) < sizeof(u32))
 253                         goto errout;
 254                 cp.fall_through =
 255                         *(u32 *) nla_data(tb[TCA_TCINDEX_FALL_THROUGH]);
 256         }
 257
 258         if (!cp.hash) {
 259                 /* Hash not specified, use perfect hash if the upper limit
 260                  * of the hashing index is below the threshold.
 261                  */
 262                 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
 263                         cp.hash = (cp.mask >> cp.shift)+1;
 264                 else
 265                         cp.hash = DEFAULT_HASH_SIZE;
 266         }
 267
 268         if (!cp.perfect && !cp.h)
 269                 cp.alloc_hash = cp.hash;
 270
 271         /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
 272          * but then, we'd fail handles that may become valid after some future
 273          * mask change. While this is extremely unlikely to ever matter,
 274          * the check below is safer (and also more backwards-compatible).
 275          */
 276         if (cp.perfect || valid_perfect_hash(&cp))
 277                 if (handle >= cp.alloc_hash)
 278                         goto errout;
 279
 280
 281         err = -ENOMEM;
 282         if (!cp.perfect && !cp.h) {
 283                 if (valid_perfect_hash(&cp)) {
 284                         cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
 285                         if (!cp.perfect)
 286                                 goto errout;
 287                         balloc = 1;
 288                 } else {
 289                         cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
 290                         if (!cp.h)
 291                                 goto errout;
 292                         balloc = 2;
 293                 }
 294         }
 295
 296         if (cp.perfect)
 297                 r = cp.perfect + handle;
 298         else
 299                 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
 300
 301         if (r == &new_filter_result) {
 302                 f = kzalloc(sizeof(*f), GFP_KERNEL);
 303                 if (!f)
 304                         goto errout_alloc;
 305         }
 306
 307         if (tb[TCA_TCINDEX_CLASSID]) {
 308                 cr.res.classid = *(u32 *) nla_data(tb[TCA_TCINDEX_CLASSID]);
 309                 tcf_bind_filter(tp, &cr.res, base);
 310         }
 311
 312         tcf_exts_change(tp, &cr.exts, &e);
 313
 314         tcf_tree_lock(tp);
 315         if (old_r && old_r != r)
 316                 memset(old_r, 0, sizeof(*old_r));
 317
 318         memcpy(p, &cp, sizeof(cp));
 319         memcpy(r, &cr, sizeof(cr));
 320
 321         if (r == &new_filter_result) {
 322                 struct tcindex_filter **fp;
 323
 324                 f->key = handle;
 325                 f->result = new_filter_result;
 326                 f->next = NULL;
 327                 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
 328                         /* nothing */;
 329                 *fp = f;
 330         }
 331         tcf_tree_unlock(tp);
 332
 333         return 0;
 334
 335 errout_alloc:
 336         if (balloc == 1)
 337                 kfree(cp.perfect);
 338         else if (balloc == 2)
 339                 kfree(cp.h);
 340 errout:
 341         tcf_exts_destroy(tp, &e);
 342         return err;
 343 }
 344
 345 static int
 346 tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 347                struct nlattr **tca, unsigned long *arg)
 348 {
 349         struct nlattr *opt = tca[TCA_OPTIONS];
 350         struct nlattr *tb[TCA_TCINDEX_MAX + 1];
 351         struct tcindex_data *p = PRIV(tp);
 352         struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
 353
 354         pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
 355             "p %p,r %p,*arg 0x%lx\n",
 356             tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
 357
 358         if (!opt)
 359                 return 0;
 360
 361         if (nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, NULL) < 0)
 362                 return -EINVAL;
 363
 364         return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE]);
 365 }
 366
 367
 368 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
 369 {
 370         struct tcindex_data *p = PRIV(tp);
 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 = PRIV(tp);
 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 tcf_proto *tp, unsigned long fh,
 433     struct sk_buff *skb, struct tcmsg *t)
 434 {
 435         struct tcindex_data *p = PRIV(tp);
 436         struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
 437         unsigned char *b = skb_tail_pointer(skb);
 438         struct nlattr *nla;
 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         nla = (struct nlattr *) b;
 444         NLA_PUT(skb, TCA_OPTIONS, 0, NULL);
 445         if (!fh) {
 446                 t->tcm_handle = ~0; /* whatever ... */
 447                 NLA_PUT(skb, TCA_TCINDEX_HASH, sizeof(p->hash), &p->hash);
 448                 NLA_PUT(skb, TCA_TCINDEX_MASK, sizeof(p->mask), &p->mask);
 449                 NLA_PUT(skb, TCA_TCINDEX_SHIFT, sizeof(p->shift), &p->shift);
 450                 NLA_PUT(skb, TCA_TCINDEX_FALL_THROUGH, sizeof(p->fall_through),
 451                     &p->fall_through);
 452                 nla->nla_len = skb_tail_pointer(skb) - b;
 453         } else {
 454                 if (p->perfect) {
 455                         t->tcm_handle = r-p->perfect;
 456                 } else {
 457                         struct tcindex_filter *f;
 458                         int i;
 459
 460                         t->tcm_handle = 0;
 461                         for (i = 0; !t->tcm_handle && i < p->hash; i++) {
 462                                 for (f = p->h[i]; !t->tcm_handle && f;
 463                                      f = f->next) {
 464                                         if (&f->result == r)
 465                                                 t->tcm_handle = f->key;
 466                                 }
 467                         }
 468                 }
 469                 pr_debug("handle = %d\n", t->tcm_handle);
 470                 if (r->res.class)
 471                         NLA_PUT(skb, TCA_TCINDEX_CLASSID, 4, &r->res.classid);
 472
 473                 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
 474                         goto nla_put_failure;
 475                 nla->nla_len = skb_tail_pointer(skb) - b;
 476
 477                 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
 478                         goto nla_put_failure;
 479         }
 480
 481         return skb->len;
 482
 483 nla_put_failure:
 484         nlmsg_trim(skb, b);
 485         return -1;
 486 }
 487
 488 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
 489         .kind           =       "tcindex",
 490         .classify       =       tcindex_classify,
 491         .init           =       tcindex_init,
 492         .destroy        =       tcindex_destroy,
 493         .get            =       tcindex_get,
 494         .put            =       tcindex_put,
 495         .change         =       tcindex_change,
 496         .delete         =       tcindex_delete,
 497         .walk           =       tcindex_walk,
 498         .dump           =       tcindex_dump,
 499         .owner          =       THIS_MODULE,
 500 };
 501
 502 static int __init init_tcindex(void)
 503 {
 504         return register_tcf_proto_ops(&cls_tcindex_ops);
 505 }
 506
 507 static void __exit exit_tcindex(void)
 508 {
 509         unregister_tcf_proto_ops(&cls_tcindex_ops);
 510 }
 511
 512 module_init(init_tcindex)
 513 module_exit(exit_tcindex)
 514 MODULE_LICENSE("GPL");