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 <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, 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 tcf_proto *tp, unsigned long base, u32 handle,
 201                   struct tcindex_data *p, struct tcindex_filter_result *r,
 202                   struct nlattr **tb, struct nlattr *est)
 203 {
 204         int err, balloc = 0;
 205         struct tcindex_filter_result new_filter_result, *old_r = r;
 206         struct tcindex_filter_result cr;
 207         struct tcindex_data cp;
 208         struct tcindex_filter *f = NULL; /* make gcc behave */
 209         struct tcf_exts e;
 210
 211         err = tcf_exts_validate(tp, tb, est, &e, &tcindex_ext_map);
 212         if (err < 0)
 213                 return err;
 214
 215         memcpy(&cp, p, sizeof(cp));
 216         memset(&new_filter_result, 0, sizeof(new_filter_result));
 217
 218         if (old_r)
 219                 memcpy(&cr, r, sizeof(cr));
 220         else
 221                 memset(&cr, 0, sizeof(cr));
 222
 223         if (tb[TCA_TCINDEX_HASH])
 224                 cp.hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
 225
 226         if (tb[TCA_TCINDEX_MASK])
 227                 cp.mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);
 228
 229         if (tb[TCA_TCINDEX_SHIFT])
 230                 cp.shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);
 231
 232         err = -EBUSY;
 233         /* Hash already allocated, make sure that we still meet the
 234          * requirements for the allocated hash.
 235          */
 236         if (cp.perfect) {
 237                 if (!valid_perfect_hash(&cp) ||
 238                     cp.hash > cp.alloc_hash)
 239                         goto errout;
 240         } else if (cp.h && cp.hash != cp.alloc_hash)
 241                 goto errout;
 242
 243         err = -EINVAL;
 244         if (tb[TCA_TCINDEX_FALL_THROUGH])
 245                 cp.fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);
 246
 247         if (!cp.hash) {
 248                 /* Hash not specified, use perfect hash if the upper limit
 249                  * of the hashing index is below the threshold.
 250                  */
 251                 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
 252                         cp.hash = (cp.mask >> cp.shift)+1;
 253                 else
 254                         cp.hash = DEFAULT_HASH_SIZE;
 255         }
 256
 257         if (!cp.perfect && !cp.h)
 258                 cp.alloc_hash = cp.hash;
 259
 260         /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
 261          * but then, we'd fail handles that may become valid after some future
 262          * mask change. While this is extremely unlikely to ever matter,
 263          * the check below is safer (and also more backwards-compatible).
 264          */
 265         if (cp.perfect || valid_perfect_hash(&cp))
 266                 if (handle >= cp.alloc_hash)
 267                         goto errout;
 268
 269
 270         err = -ENOMEM;
 271         if (!cp.perfect && !cp.h) {
 272                 if (valid_perfect_hash(&cp)) {
 273                         cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
 274                         if (!cp.perfect)
 275                                 goto errout;
 276                         balloc = 1;
 277                 } else {
 278                         cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
 279                         if (!cp.h)
 280                                 goto errout;
 281                         balloc = 2;
 282                 }
 283         }
 284
 285         if (cp.perfect)
 286                 r = cp.perfect + handle;
 287         else
 288                 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
 289
 290         if (r == &new_filter_result) {
 291                 f = kzalloc(sizeof(*f), GFP_KERNEL);
 292                 if (!f)
 293                         goto errout_alloc;
 294         }
 295
 296         if (tb[TCA_TCINDEX_CLASSID]) {
 297                 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
 298                 tcf_bind_filter(tp, &cr.res, base);
 299         }
 300
 301         tcf_exts_change(tp, &cr.exts, &e);
 302
 303         tcf_tree_lock(tp);
 304         if (old_r && old_r != r)
 305                 memset(old_r, 0, sizeof(*old_r));
 306
 307         memcpy(p, &cp, sizeof(cp));
 308         memcpy(r, &cr, sizeof(cr));
 309
 310         if (r == &new_filter_result) {
 311                 struct tcindex_filter **fp;
 312
 313                 f->key = handle;
 314                 f->result = new_filter_result;
 315                 f->next = NULL;
 316                 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
 317                         /* nothing */;
 318                 *fp = f;
 319         }
 320         tcf_tree_unlock(tp);
 321
 322         return 0;
 323
 324 errout_alloc:
 325         if (balloc == 1)
 326                 kfree(cp.perfect);
 327         else if (balloc == 2)
 328                 kfree(cp.h);
 329 errout:
 330         tcf_exts_destroy(tp, &e);
 331         return err;
 332 }
 333
 334 static int
 335 tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 336                struct nlattr **tca, unsigned long *arg)
 337 {
 338         struct nlattr *opt = tca[TCA_OPTIONS];
 339         struct nlattr *tb[TCA_TCINDEX_MAX + 1];
 340         struct tcindex_data *p = PRIV(tp);
 341         struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
 342         int err;
 343
 344         pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
 345             "p %p,r %p,*arg 0x%lx\n",
 346             tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
 347
 348         if (!opt)
 349                 return 0;
 350
 351         err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
 352         if (err < 0)
 353                 return err;
 354
 355         return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE]);
 356 }
 357
 358
 359 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
 360 {
 361         struct tcindex_data *p = PRIV(tp);
 362         struct tcindex_filter *f, *next;
 363         int i;
 364
 365         pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
 366         if (p->perfect) {
 367                 for (i = 0; i < p->hash; i++) {
 368                         if (!p->perfect[i].res.class)
 369                                 continue;
 370                         if (walker->count >= walker->skip) {
 371                                 if (walker->fn(tp,
 372                                     (unsigned long) (p->perfect+i), walker)
 373                                      < 0) {
 374                                         walker->stop = 1;
 375                                         return;
 376                                 }
 377                         }
 378                         walker->count++;
 379                 }
 380         }
 381         if (!p->h)
 382                 return;
 383         for (i = 0; i < p->hash; i++) {
 384                 for (f = p->h[i]; f; f = next) {
 385                         next = f->next;
 386                         if (walker->count >= walker->skip) {
 387                                 if (walker->fn(tp, (unsigned long) &f->result,
 388                                     walker) < 0) {
 389                                         walker->stop = 1;
 390                                         return;
 391                                 }
 392                         }
 393                         walker->count++;
 394                 }
 395         }
 396 }
 397
 398
 399 static int tcindex_destroy_element(struct tcf_proto *tp,
 400     unsigned long arg, struct tcf_walker *walker)
 401 {
 402         return __tcindex_delete(tp, arg, 0);
 403 }
 404
 405
 406 static void tcindex_destroy(struct tcf_proto *tp)
 407 {
 408         struct tcindex_data *p = PRIV(tp);
 409         struct tcf_walker walker;
 410
 411         pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
 412         walker.count = 0;
 413         walker.skip = 0;
 414         walker.fn = &tcindex_destroy_element;
 415         tcindex_walk(tp, &walker);
 416         kfree(p->perfect);
 417         kfree(p->h);
 418         kfree(p);
 419         tp->root = NULL;
 420 }
 421
 422
 423 static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
 424     struct sk_buff *skb, struct tcmsg *t)
 425 {
 426         struct tcindex_data *p = PRIV(tp);
 427         struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
 428         unsigned char *b = skb_tail_pointer(skb);
 429         struct nlattr *nest;
 430
 431         pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
 432                  tp, fh, skb, t, p, r, b);
 433         pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
 434
 435         nest = nla_nest_start(skb, TCA_OPTIONS);
 436         if (nest == NULL)
 437                 goto nla_put_failure;
 438
 439         if (!fh) {
 440                 t->tcm_handle = ~0; /* whatever ... */
 441                 NLA_PUT_U32(skb, TCA_TCINDEX_HASH, p->hash);
 442                 NLA_PUT_U16(skb, TCA_TCINDEX_MASK, p->mask);
 443                 NLA_PUT_U32(skb, TCA_TCINDEX_SHIFT, p->shift);
 444                 NLA_PUT_U32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through);
 445                 nla_nest_end(skb, nest);
 446         } else {
 447                 if (p->perfect) {
 448                         t->tcm_handle = r-p->perfect;
 449                 } else {
 450                         struct tcindex_filter *f;
 451                         int i;
 452
 453                         t->tcm_handle = 0;
 454                         for (i = 0; !t->tcm_handle && i < p->hash; i++) {
 455                                 for (f = p->h[i]; !t->tcm_handle && f;
 456                                      f = f->next) {
 457                                         if (&f->result == r)
 458                                                 t->tcm_handle = f->key;
 459                                 }
 460                         }
 461                 }
 462                 pr_debug("handle = %d\n", t->tcm_handle);
 463                 if (r->res.class)
 464                         NLA_PUT_U32(skb, TCA_TCINDEX_CLASSID, r->res.classid);
 465
 466                 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
 467                         goto nla_put_failure;
 468                 nla_nest_end(skb, nest);
 469
 470                 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
 471                         goto nla_put_failure;
 472         }
 473
 474         return skb->len;
 475
 476 nla_put_failure:
 477         nlmsg_trim(skb, b);
 478         return -1;
 479 }
 480
 481 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
 482         .kind           =       "tcindex",
 483         .classify       =       tcindex_classify,
 484         .init           =       tcindex_init,
 485         .destroy        =       tcindex_destroy,
 486         .get            =       tcindex_get,
 487         .put            =       tcindex_put,
 488         .change         =       tcindex_change,
 489         .delete         =       tcindex_delete,
 490         .walk           =       tcindex_walk,
 491         .dump           =       tcindex_dump,
 492         .owner          =       THIS_MODULE,
 493 };
 494
 495 static int __init init_tcindex(void)
 496 {
 497         return register_tcf_proto_ops(&cls_tcindex_ops);
 498 }
 499
 500 static void __exit exit_tcindex(void)
 501 {
 502         unregister_tcf_proto_ops(&cls_tcindex_ops);
 503 }
 504
 505 module_init(init_tcindex)
 506 module_exit(exit_tcindex)
 507 MODULE_LICENSE("GPL");