SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/sched/cls_tcindex.c

   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 = nla_get_u32(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 = nla_get_u16(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 = nla_get_u32(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 = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
 255         }
 256
 257         if (!cp.hash) {
 258                 /* Hash not specified, use perfect hash if the upper limit
 259                  * of the hashing index is below the threshold.
 260                  */
 261                 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
 262                         cp.hash = (cp.mask >> cp.shift)+1;
 263                 else
 264                         cp.hash = DEFAULT_HASH_SIZE;
 265         }
 266
 267         if (!cp.perfect && !cp.h)
 268                 cp.alloc_hash = cp.hash;
 269
 270         /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
 271          * but then, we'd fail handles that may become valid after some future
 272          * mask change. While this is extremely unlikely to ever matter,
 273          * the check below is safer (and also more backwards-compatible).
 274          */
 275         if (cp.perfect || valid_perfect_hash(&cp))
 276                 if (handle >= cp.alloc_hash)
 277                         goto errout;
 278
 279
 280         err = -ENOMEM;
 281         if (!cp.perfect && !cp.h) {
 282                 if (valid_perfect_hash(&cp)) {
 283                         cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
 284                         if (!cp.perfect)
 285                                 goto errout;
 286                         balloc = 1;
 287                 } else {
 288                         cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
 289                         if (!cp.h)
 290                                 goto errout;
 291                         balloc = 2;
 292                 }
 293         }
 294
 295         if (cp.perfect)
 296                 r = cp.perfect + handle;
 297         else
 298                 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
 299
 300         if (r == &new_filter_result) {
 301                 f = kzalloc(sizeof(*f), GFP_KERNEL);
 302                 if (!f)
 303                         goto errout_alloc;
 304         }
 305
 306         if (tb[TCA_TCINDEX_CLASSID]) {
 307                 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
 308                 tcf_bind_filter(tp, &cr.res, base);
 309         }
 310
 311         tcf_exts_change(tp, &cr.exts, &e);
 312
 313         tcf_tree_lock(tp);
 314         if (old_r && old_r != r)
 315                 memset(old_r, 0, sizeof(*old_r));
 316
 317         memcpy(p, &cp, sizeof(cp));
 318         memcpy(r, &cr, sizeof(cr));
 319
 320         if (r == &new_filter_result) {
 321                 struct tcindex_filter **fp;
 322
 323                 f->key = handle;
 324                 f->result = new_filter_result;
 325                 f->next = NULL;
 326                 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
 327                         /* nothing */;
 328                 *fp = f;
 329         }
 330         tcf_tree_unlock(tp);
 331
 332         return 0;
 333
 334 errout_alloc:
 335         if (balloc == 1)
 336                 kfree(cp.perfect);
 337         else if (balloc == 2)
 338                 kfree(cp.h);
 339 errout:
 340         tcf_exts_destroy(tp, &e);
 341         return err;
 342 }
 343
 344 static int
 345 tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 346                struct nlattr **tca, unsigned long *arg)
 347 {
 348         struct nlattr *opt = tca[TCA_OPTIONS];
 349         struct nlattr *tb[TCA_TCINDEX_MAX + 1];
 350         struct tcindex_data *p = PRIV(tp);
 351         struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
 352         int err;
 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         err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, NULL);
 362         if (err < 0)
 363                 return err;
 364
 365         return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE]);
 366 }
 367
 368
 369 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
 370 {
 371         struct tcindex_data *p = PRIV(tp);
 372         struct tcindex_filter *f, *next;
 373         int i;
 374
 375         pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
 376         if (p->perfect) {
 377                 for (i = 0; i < p->hash; i++) {
 378                         if (!p->perfect[i].res.class)
 379                                 continue;
 380                         if (walker->count >= walker->skip) {
 381                                 if (walker->fn(tp,
 382                                     (unsigned long) (p->perfect+i), walker)
 383                                      < 0) {
 384                                         walker->stop = 1;
 385                                         return;
 386                                 }
 387                         }
 388                         walker->count++;
 389                 }
 390         }
 391         if (!p->h)
 392                 return;
 393         for (i = 0; i < p->hash; i++) {
 394                 for (f = p->h[i]; f; f = next) {
 395                         next = f->next;
 396                         if (walker->count >= walker->skip) {
 397                                 if (walker->fn(tp, (unsigned long) &f->result,
 398                                     walker) < 0) {
 399                                         walker->stop = 1;
 400                                         return;
 401                                 }
 402                         }
 403                         walker->count++;
 404                 }
 405         }
 406 }
 407
 408
 409 static int tcindex_destroy_element(struct tcf_proto *tp,
 410     unsigned long arg, struct tcf_walker *walker)
 411 {
 412         return __tcindex_delete(tp, arg, 0);
 413 }
 414
 415
 416 static void tcindex_destroy(struct tcf_proto *tp)
 417 {
 418         struct tcindex_data *p = PRIV(tp);
 419         struct tcf_walker walker;
 420
 421         pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
 422         walker.count = 0;
 423         walker.skip = 0;
 424         walker.fn = &tcindex_destroy_element;
 425         tcindex_walk(tp, &walker);
 426         kfree(p->perfect);
 427         kfree(p->h);
 428         kfree(p);
 429         tp->root = NULL;
 430 }
 431
 432
 433 static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
 434     struct sk_buff *skb, struct tcmsg *t)
 435 {
 436         struct tcindex_data *p = PRIV(tp);
 437         struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
 438         unsigned char *b = skb_tail_pointer(skb);
 439         struct nlattr *nest;
 440
 441         pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
 442                  tp, fh, skb, t, p, r, b);
 443         pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
 444
 445         nest = nla_nest_start(skb, TCA_OPTIONS);
 446         if (nest == NULL)
 447                 goto nla_put_failure;
 448
 449         if (!fh) {
 450                 t->tcm_handle = ~0; /* whatever ... */
 451                 NLA_PUT_U32(skb, TCA_TCINDEX_HASH, p->hash);
 452                 NLA_PUT_U16(skb, TCA_TCINDEX_MASK, p->mask);
 453                 NLA_PUT_U32(skb, TCA_TCINDEX_SHIFT, p->shift);
 454                 NLA_PUT_U32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through);
 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
 476                 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
 477                         goto nla_put_failure;
 478                 nla_nest_end(skb, nest);
 479
 480                 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
 481                         goto nla_put_failure;
 482         }
 483
 484         return skb->len;
 485
 486 nla_put_failure:
 487         nlmsg_trim(skb, b);
 488         return -1;
 489 }
 490
 491 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
 492         .kind           =       "tcindex",
 493         .classify       =       tcindex_classify,
 494         .init           =       tcindex_init,
 495         .destroy        =       tcindex_destroy,
 496         .get            =       tcindex_get,
 497         .put            =       tcindex_put,
 498         .change         =       tcindex_change,
 499         .delete         =       tcindex_delete,
 500         .walk           =       tcindex_walk,
 501         .dump           =       tcindex_dump,
 502         .owner          =       THIS_MODULE,
 503 };
 504
 505 static int __init init_tcindex(void)
 506 {
 507         return register_tcf_proto_ops(&cls_tcindex_ops);
 508 }
 509
 510 static void __exit exit_tcindex(void)
 511 {
 512         unregister_tcf_proto_ops(&cls_tcindex_ops);
 513 }
 514
 515 module_init(init_tcindex)
 516 module_exit(exit_tcindex)
 517 MODULE_LICENSE("GPL");