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/config.h>
   8 #include <linux/module.h>
   9 #include <linux/types.h>
  10 #include <linux/kernel.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/errno.h>
  13 #include <linux/netdevice.h>
  14 #include <net/ip.h>
  15 #include <net/act_api.h>
  16 #include <net/pkt_cls.h>
  17 #include <net/route.h>
  18
  19
  20 /*
  21  * Not quite sure if we need all the xchgs Alexey uses when accessing things.
  22  * Can always add them later ... :)
  23  */
  24
  25 /*
  26  * Passing parameters to the root seems to be done more awkwardly than really
  27  * necessary. At least, u32 doesn't seem to use such dirty hacks. To be
  28  * verified. FIXME.
  29  */
  30
  31 #define PERFECT_HASH_THRESHOLD  64      /* use perfect hash if not bigger */
  32 #define DEFAULT_HASH_SIZE       64      /* optimized for diffserv */
  33
  34
  35 #if 1 /* control */
  36 #define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
  37 #else
  38 #define DPRINTK(format,args...)
  39 #endif
  40
  41 #if 0 /* data */
  42 #define D2PRINTK(format,args...) printk(KERN_DEBUG format,##args)
  43 #else
  44 #define D2PRINTK(format,args...)
  45 #endif
  46
  47
  48 #define PRIV(tp)        ((struct tcindex_data *) (tp)->root)
  49
  50
  51 struct tcindex_filter_result {
  52         struct tcf_exts         exts;
  53         struct tcf_result       res;
  54 };
  55
  56 struct tcindex_filter {
  57         u16 key;
  58         struct tcindex_filter_result result;
  59         struct tcindex_filter *next;
  60 };
  61
  62
  63 struct tcindex_data {
  64         struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
  65         struct tcindex_filter **h; /* imperfect hash; only used if !perfect;
  66                                       NULL if unused */
  67         u16 mask;               /* AND key with mask */
  68         int shift;              /* shift ANDed key to the right */
  69         int hash;               /* hash table size; 0 if undefined */
  70         int alloc_hash;         /* allocated size */
  71         int fall_through;       /* 0: only classify if explicit match */
  72 };
  73
  74 static struct tcf_ext_map tcindex_ext_map = {
  75         .police = TCA_TCINDEX_POLICE,
  76         .action = TCA_TCINDEX_ACT
  77 };
  78
  79 static inline int
  80 tcindex_filter_is_set(struct tcindex_filter_result *r)
  81 {
  82         return tcf_exts_is_predicative(&r->exts) || r->res.classid;
  83 }
  84
  85 static struct tcindex_filter_result *
  86 tcindex_lookup(struct tcindex_data *p, u16 key)
  87 {
  88         struct tcindex_filter *f;
  89
  90         if (p->perfect)
  91                 return tcindex_filter_is_set(p->perfect + key) ?
  92                         p->perfect + key : NULL;
  93         else if (p->h) {
  94                 for (f = p->h[key % p->hash]; f; f = f->next)
  95                         if (f->key == key)
  96                                 return &f->result;
  97         }
  98
  99         return NULL;
 100 }
 101
 102
 103 static int tcindex_classify(struct sk_buff *skb, struct tcf_proto *tp,
 104                             struct tcf_result *res)
 105 {
 106         struct tcindex_data *p = PRIV(tp);
 107         struct tcindex_filter_result *f;
 108         int key = (skb->tc_index & p->mask) >> p->shift;
 109
 110         D2PRINTK("tcindex_classify(skb %p,tp %p,res %p),p %p\n",skb,tp,res,p);
 111
 112         f = tcindex_lookup(p, key);
 113         if (!f) {
 114                 if (!p->fall_through)
 115                         return -1;
 116                 res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key);
 117                 res->class = 0;
 118                 D2PRINTK("alg 0x%x\n",res->classid);
 119                 return 0;
 120         }
 121         *res = f->res;
 122         D2PRINTK("map 0x%x\n",res->classid);
 123
 124         return tcf_exts_exec(skb, &f->exts, res);
 125 }
 126
 127
 128 static unsigned long tcindex_get(struct tcf_proto *tp, u32 handle)
 129 {
 130         struct tcindex_data *p = PRIV(tp);
 131         struct tcindex_filter_result *r;
 132
 133         DPRINTK("tcindex_get(tp %p,handle 0x%08x)\n",tp,handle);
 134         if (p->perfect && handle >= p->alloc_hash)
 135                 return 0;
 136         r = tcindex_lookup(p, handle);
 137         return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL;
 138 }
 139
 140
 141 static void tcindex_put(struct tcf_proto *tp, unsigned long f)
 142 {
 143         DPRINTK("tcindex_put(tp %p,f 0x%lx)\n",tp,f);
 144 }
 145
 146
 147 static int tcindex_init(struct tcf_proto *tp)
 148 {
 149         struct tcindex_data *p;
 150
 151         DPRINTK("tcindex_init(tp %p)\n",tp);
 152         p = kmalloc(sizeof(struct tcindex_data),GFP_KERNEL);
 153         if (!p)
 154                 return -ENOMEM;
 155
 156         memset(p, 0, sizeof(*p));
 157         p->mask = 0xffff;
 158         p->hash = DEFAULT_HASH_SIZE;
 159         p->fall_through = 1;
 160
 161         tp->root = p;
 162         return 0;
 163 }
 164
 165
 166 static int
 167 __tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
 168 {
 169         struct tcindex_data *p = PRIV(tp);
 170         struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
 171         struct tcindex_filter *f = NULL;
 172
 173         DPRINTK("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n",tp,arg,p,f);
 174         if (p->perfect) {
 175                 if (!r->res.class)
 176                         return -ENOENT;
 177         } else {
 178                 int i;
 179                 struct tcindex_filter **walk = NULL;
 180
 181                 for (i = 0; i < p->hash; i++)
 182                         for (walk = p->h+i; *walk; walk = &(*walk)->next)
 183                                 if (&(*walk)->result == r)
 184                                         goto found;
 185                 return -ENOENT;
 186
 187 found:
 188                 f = *walk;
 189                 if (lock)
 190                         tcf_tree_lock(tp);
 191                 *walk = f->next;
 192                 if (lock)
 193                         tcf_tree_unlock(tp);
 194         }
 195         tcf_unbind_filter(tp, &r->res);
 196         tcf_exts_destroy(tp, &r->exts);
 197         kfree(f);
 198         return 0;
 199 }
 200
 201 static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
 202 {
 203         return __tcindex_delete(tp, arg, 1);
 204 }
 205
 206 static inline int
 207 valid_perfect_hash(struct tcindex_data *p)
 208 {
 209         return  p->hash > (p->mask >> p->shift);
 210 }
 211
 212 static int
 213 tcindex_set_parms(struct tcf_proto *tp, unsigned long base, u32 handle,
 214                   struct tcindex_data *p, struct tcindex_filter_result *r,
 215                   struct rtattr **tb, struct rtattr *est)
 216 {
 217         int err, balloc = 0;
 218         struct tcindex_filter_result new_filter_result, *old_r = r;
 219         struct tcindex_filter_result cr;
 220         struct tcindex_data cp;
 221         struct tcindex_filter *f = NULL; /* make gcc behave */
 222         struct tcf_exts e;
 223
 224         err = tcf_exts_validate(tp, tb, est, &e, &tcindex_ext_map);
 225         if (err < 0)
 226                 return err;
 227
 228         memcpy(&cp, p, sizeof(cp));
 229         memset(&new_filter_result, 0, sizeof(new_filter_result));
 230
 231         if (old_r)
 232                 memcpy(&cr, r, sizeof(cr));
 233         else
 234                 memset(&cr, 0, sizeof(cr));
 235
 236         err = -EINVAL;
 237         if (tb[TCA_TCINDEX_HASH-1]) {
 238                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_HASH-1]) < sizeof(u32))
 239                         goto errout;
 240                 cp.hash = *(u32 *) RTA_DATA(tb[TCA_TCINDEX_HASH-1]);
 241         }
 242
 243         if (tb[TCA_TCINDEX_MASK-1]) {
 244                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_MASK-1]) < sizeof(u16))
 245                         goto errout;
 246                 cp.mask = *(u16 *) RTA_DATA(tb[TCA_TCINDEX_MASK-1]);
 247         }
 248
 249         if (tb[TCA_TCINDEX_SHIFT-1]) {
 250                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_SHIFT-1]) < sizeof(u16))
 251                         goto errout;
 252                 cp.shift = *(u16 *) RTA_DATA(tb[TCA_TCINDEX_SHIFT-1]);
 253         }
 254
 255         err = -EBUSY;
 256         /* Hash already allocated, make sure that we still meet the
 257          * requirements for the allocated hash.
 258          */
 259         if (cp.perfect) {
 260                 if (!valid_perfect_hash(&cp) ||
 261                     cp.hash > cp.alloc_hash)
 262                         goto errout;
 263         } else if (cp.h && cp.hash != cp.alloc_hash)
 264                 goto errout;
 265
 266         err = -EINVAL;
 267         if (tb[TCA_TCINDEX_FALL_THROUGH-1]) {
 268                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_FALL_THROUGH-1]) < sizeof(u32))
 269                         goto errout;
 270                 cp.fall_through =
 271                         *(u32 *) RTA_DATA(tb[TCA_TCINDEX_FALL_THROUGH-1]);
 272         }
 273
 274         if (!cp.hash) {
 275                 /* Hash not specified, use perfect hash if the upper limit
 276                  * of the hashing index is below the threshold.
 277                  */
 278                 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
 279                         cp.hash = (cp.mask >> cp.shift)+1;
 280                 else
 281                         cp.hash = DEFAULT_HASH_SIZE;
 282         }
 283
 284         if (!cp.perfect && !cp.h)
 285                 cp.alloc_hash = cp.hash;
 286
 287         /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
 288          * but then, we'd fail handles that may become valid after some future
 289          * mask change. While this is extremely unlikely to ever matter,
 290          * the check below is safer (and also more backwards-compatible).
 291          */
 292         if (cp.perfect || valid_perfect_hash(&cp))
 293                 if (handle >= cp.alloc_hash)
 294                         goto errout;
 295
 296
 297         err = -ENOMEM;
 298         if (!cp.perfect && !cp.h) {
 299                 if (valid_perfect_hash(&cp)) {
 300                         cp.perfect = kmalloc(cp.hash * sizeof(*r), GFP_KERNEL);
 301                         if (!cp.perfect)
 302                                 goto errout;
 303                         memset(cp.perfect, 0, cp.hash * sizeof(*r));
 304                         balloc = 1;
 305                 } else {
 306                         cp.h = kmalloc(cp.hash * sizeof(f), GFP_KERNEL);
 307                         if (!cp.h)
 308                                 goto errout;
 309                         memset(cp.h, 0, cp.hash * sizeof(f));
 310                         balloc = 2;
 311                 }
 312         }
 313
 314         if (cp.perfect)
 315                 r = cp.perfect + handle;
 316         else
 317                 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
 318
 319         if (r == &new_filter_result) {
 320                 f = kmalloc(sizeof(*f), GFP_KERNEL);
 321                 if (!f)
 322                         goto errout_alloc;
 323                 memset(f, 0, sizeof(*f));
 324         }
 325
 326         if (tb[TCA_TCINDEX_CLASSID-1]) {
 327                 cr.res.classid = *(u32 *) RTA_DATA(tb[TCA_TCINDEX_CLASSID-1]);
 328                 tcf_bind_filter(tp, &cr.res, base);
 329         }
 330
 331         tcf_exts_change(tp, &cr.exts, &e);
 332
 333         tcf_tree_lock(tp);
 334         if (old_r && old_r != r)
 335                 memset(old_r, 0, sizeof(*old_r));
 336
 337         memcpy(p, &cp, sizeof(cp));
 338         memcpy(r, &cr, sizeof(cr));
 339
 340         if (r == &new_filter_result) {
 341                 struct tcindex_filter **fp;
 342
 343                 f->key = handle;
 344                 f->result = new_filter_result;
 345                 f->next = NULL;
 346                 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
 347                         /* nothing */;
 348                 *fp = f;
 349         }
 350         tcf_tree_unlock(tp);
 351
 352         return 0;
 353
 354 errout_alloc:
 355         if (balloc == 1)
 356                 kfree(cp.perfect);
 357         else if (balloc == 2)
 358                 kfree(cp.h);
 359 errout:
 360         tcf_exts_destroy(tp, &e);
 361         return err;
 362 }
 363
 364 static int
 365 tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 366                struct rtattr **tca, unsigned long *arg)
 367 {
 368         struct rtattr *opt = tca[TCA_OPTIONS-1];
 369         struct rtattr *tb[TCA_TCINDEX_MAX];
 370         struct tcindex_data *p = PRIV(tp);
 371         struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
 372
 373         DPRINTK("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
 374             "p %p,r %p,*arg 0x%lx\n",
 375             tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
 376
 377         if (!opt)
 378                 return 0;
 379
 380         if (rtattr_parse_nested(tb, TCA_TCINDEX_MAX, opt) < 0)
 381                 return -EINVAL;
 382
 383         return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE-1]);
 384 }
 385
 386
 387 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
 388 {
 389         struct tcindex_data *p = PRIV(tp);
 390         struct tcindex_filter *f,*next;
 391         int i;
 392
 393         DPRINTK("tcindex_walk(tp %p,walker %p),p %p\n",tp,walker,p);
 394         if (p->perfect) {
 395                 for (i = 0; i < p->hash; i++) {
 396                         if (!p->perfect[i].res.class)
 397                                 continue;
 398                         if (walker->count >= walker->skip) {
 399                                 if (walker->fn(tp,
 400                                     (unsigned long) (p->perfect+i), walker)
 401                                      < 0) {
 402                                         walker->stop = 1;
 403                                         return;
 404                                 }
 405                         }
 406                         walker->count++;
 407                 }
 408         }
 409         if (!p->h)
 410                 return;
 411         for (i = 0; i < p->hash; i++) {
 412                 for (f = p->h[i]; f; f = next) {
 413                         next = f->next;
 414                         if (walker->count >= walker->skip) {
 415                                 if (walker->fn(tp,(unsigned long) &f->result,
 416                                     walker) < 0) {
 417                                         walker->stop = 1;
 418                                         return;
 419                                 }
 420                         }
 421                         walker->count++;
 422                 }
 423         }
 424 }
 425
 426
 427 static int tcindex_destroy_element(struct tcf_proto *tp,
 428     unsigned long arg, struct tcf_walker *walker)
 429 {
 430         return __tcindex_delete(tp, arg, 0);
 431 }
 432
 433
 434 static void tcindex_destroy(struct tcf_proto *tp)
 435 {
 436         struct tcindex_data *p = PRIV(tp);
 437         struct tcf_walker walker;
 438
 439         DPRINTK("tcindex_destroy(tp %p),p %p\n",tp,p);
 440         walker.count = 0;
 441         walker.skip = 0;
 442         walker.fn = &tcindex_destroy_element;
 443         tcindex_walk(tp,&walker);
 444         kfree(p->perfect);
 445         kfree(p->h);
 446         kfree(p);
 447         tp->root = NULL;
 448 }
 449
 450
 451 static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
 452     struct sk_buff *skb, struct tcmsg *t)
 453 {
 454         struct tcindex_data *p = PRIV(tp);
 455         struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
 456         unsigned char *b = skb->tail;
 457         struct rtattr *rta;
 458
 459         DPRINTK("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
 460             tp,fh,skb,t,p,r,b);
 461         DPRINTK("p->perfect %p p->h %p\n",p->perfect,p->h);
 462         rta = (struct rtattr *) b;
 463         RTA_PUT(skb,TCA_OPTIONS,0,NULL);
 464         if (!fh) {
 465                 t->tcm_handle = ~0; /* whatever ... */
 466                 RTA_PUT(skb,TCA_TCINDEX_HASH,sizeof(p->hash),&p->hash);
 467                 RTA_PUT(skb,TCA_TCINDEX_MASK,sizeof(p->mask),&p->mask);
 468                 RTA_PUT(skb,TCA_TCINDEX_SHIFT,sizeof(p->shift),&p->shift);
 469                 RTA_PUT(skb,TCA_TCINDEX_FALL_THROUGH,sizeof(p->fall_through),
 470                     &p->fall_through);
 471                 rta->rta_len = skb->tail-b;
 472         } else {
 473                 if (p->perfect) {
 474                         t->tcm_handle = r-p->perfect;
 475                 } else {
 476                         struct tcindex_filter *f;
 477                         int i;
 478
 479                         t->tcm_handle = 0;
 480                         for (i = 0; !t->tcm_handle && i < p->hash; i++) {
 481                                 for (f = p->h[i]; !t->tcm_handle && f;
 482                                      f = f->next) {
 483                                         if (&f->result == r)
 484                                                 t->tcm_handle = f->key;
 485                                 }
 486                         }
 487                 }
 488                 DPRINTK("handle = %d\n",t->tcm_handle);
 489                 if (r->res.class)
 490                         RTA_PUT(skb, TCA_TCINDEX_CLASSID, 4, &r->res.classid);
 491
 492                 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
 493                         goto rtattr_failure;
 494                 rta->rta_len = skb->tail-b;
 495
 496                 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
 497                         goto rtattr_failure;
 498         }
 499
 500         return skb->len;
 501
 502 rtattr_failure:
 503         skb_trim(skb, b - skb->data);
 504         return -1;
 505 }
 506
 507 static struct tcf_proto_ops cls_tcindex_ops = {
 508         .next           =       NULL,
 509         .kind           =       "tcindex",
 510         .classify       =       tcindex_classify,
 511         .init           =       tcindex_init,
 512         .destroy        =       tcindex_destroy,
 513         .get            =       tcindex_get,
 514         .put            =       tcindex_put,
 515         .change         =       tcindex_change,
 516         .delete         =       tcindex_delete,
 517         .walk           =       tcindex_walk,
 518         .dump           =       tcindex_dump,
 519         .owner          =       THIS_MODULE,
 520 };
 521
 522 static int __init init_tcindex(void)
 523 {
 524         return register_tcf_proto_ops(&cls_tcindex_ops);
 525 }
 526
 527 static void __exit exit_tcindex(void)
 528 {
 529         unregister_tcf_proto_ops(&cls_tcindex_ops);
 530 }
 531
 532 module_init(init_tcindex)
 533 module_exit(exit_tcindex)
 534 MODULE_LICENSE("GPL");