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