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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/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         if (f)
 198                 kfree(f);
 199         return 0;
 200 }
 201
 202 static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
 203 {
 204         return __tcindex_delete(tp, arg, 1);
 205 }
 206
 207 static inline int
 208 valid_perfect_hash(struct tcindex_data *p)
 209 {
 210         return  p->hash > (p->mask >> p->shift);
 211 }
 212
 213 static int
 214 tcindex_set_parms(struct tcf_proto *tp, unsigned long base, u32 handle,
 215                   struct tcindex_data *p, struct tcindex_filter_result *r,
 216                   struct rtattr **tb, struct rtattr *est)
 217 {
 218         int err, balloc = 0;
 219         struct tcindex_filter_result new_filter_result, *old_r = r;
 220         struct tcindex_filter_result cr;
 221         struct tcindex_data cp;
 222         struct tcindex_filter *f = NULL; /* make gcc behave */
 223         struct tcf_exts e;
 224
 225         err = tcf_exts_validate(tp, tb, est, &e, &tcindex_ext_map);
 226         if (err < 0)
 227                 return err;
 228
 229         memcpy(&cp, p, sizeof(cp));
 230         memset(&new_filter_result, 0, sizeof(new_filter_result));
 231
 232         if (old_r)
 233                 memcpy(&cr, r, sizeof(cr));
 234         else
 235                 memset(&cr, 0, sizeof(cr));
 236
 237         err = -EINVAL;
 238         if (tb[TCA_TCINDEX_HASH-1]) {
 239                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_HASH-1]) < sizeof(u32))
 240                         goto errout;
 241                 cp.hash = *(u32 *) RTA_DATA(tb[TCA_TCINDEX_HASH-1]);
 242         }
 243
 244         if (tb[TCA_TCINDEX_MASK-1]) {
 245                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_MASK-1]) < sizeof(u16))
 246                         goto errout;
 247                 cp.mask = *(u16 *) RTA_DATA(tb[TCA_TCINDEX_MASK-1]);
 248         }
 249
 250         if (tb[TCA_TCINDEX_SHIFT-1]) {
 251                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_SHIFT-1]) < sizeof(u16))
 252                         goto errout;
 253                 cp.shift = *(u16 *) RTA_DATA(tb[TCA_TCINDEX_SHIFT-1]);
 254         }
 255
 256         err = -EBUSY;
 257         /* Hash already allocated, make sure that we still meet the
 258          * requirements for the allocated hash.
 259          */
 260         if (cp.perfect) {
 261                 if (!valid_perfect_hash(&cp) ||
 262                     cp.hash > cp.alloc_hash)
 263                         goto errout;
 264         } else if (cp.h && cp.hash != cp.alloc_hash)
 265                 goto errout;
 266
 267         err = -EINVAL;
 268         if (tb[TCA_TCINDEX_FALL_THROUGH-1]) {
 269                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_FALL_THROUGH-1]) < sizeof(u32))
 270                         goto errout;
 271                 cp.fall_through =
 272                         *(u32 *) RTA_DATA(tb[TCA_TCINDEX_FALL_THROUGH-1]);
 273         }
 274
 275         if (!cp.hash) {
 276                 /* Hash not specified, use perfect hash if the upper limit
 277                  * of the hashing index is below the threshold.
 278                  */
 279                 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
 280                         cp.hash = (cp.mask >> cp.shift)+1;
 281                 else
 282                         cp.hash = DEFAULT_HASH_SIZE;
 283         }
 284
 285         if (!cp.perfect && !cp.h)
 286                 cp.alloc_hash = cp.hash;
 287
 288         /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
 289          * but then, we'd fail handles that may become valid after some future
 290          * mask change. While this is extremely unlikely to ever matter,
 291          * the check below is safer (and also more backwards-compatible).
 292          */
 293         if (cp.perfect || valid_perfect_hash(&cp))
 294                 if (handle >= cp.alloc_hash)
 295                         goto errout;
 296
 297
 298         err = -ENOMEM;
 299         if (!cp.perfect && !cp.h) {
 300                 if (valid_perfect_hash(&cp)) {
 301                         cp.perfect = kmalloc(cp.hash * sizeof(*r), GFP_KERNEL);
 302                         if (!cp.perfect)
 303                                 goto errout;
 304                         memset(cp.perfect, 0, cp.hash * sizeof(*r));
 305                         balloc = 1;
 306                 } else {
 307                         cp.h = kmalloc(cp.hash * sizeof(f), GFP_KERNEL);
 308                         if (!cp.h)
 309                                 goto errout;
 310                         memset(cp.h, 0, cp.hash * sizeof(f));
 311                         balloc = 2;
 312                 }
 313         }
 314
 315         if (cp.perfect)
 316                 r = cp.perfect + handle;
 317         else
 318                 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
 319
 320         if (r == &new_filter_result) {
 321                 f = kmalloc(sizeof(*f), GFP_KERNEL);
 322                 if (!f)
 323                         goto errout_alloc;
 324                 memset(f, 0, sizeof(*f));
 325         }
 326
 327         if (tb[TCA_TCINDEX_CLASSID-1]) {
 328                 cr.res.classid = *(u32 *) RTA_DATA(tb[TCA_TCINDEX_CLASSID-1]);
 329                 tcf_bind_filter(tp, &cr.res, base);
 330         }
 331
 332         tcf_exts_change(tp, &cr.exts, &e);
 333
 334         tcf_tree_lock(tp);
 335         if (old_r && old_r != r)
 336                 memset(old_r, 0, sizeof(*old_r));
 337
 338         memcpy(p, &cp, sizeof(cp));
 339         memcpy(r, &cr, sizeof(cr));
 340
 341         if (r == &new_filter_result) {
 342                 struct tcindex_filter **fp;
 343
 344                 f->key = handle;
 345                 f->result = new_filter_result;
 346                 f->next = NULL;
 347                 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
 348                         /* nothing */;
 349                 *fp = f;
 350         }
 351         tcf_tree_unlock(tp);
 352
 353         return 0;
 354
 355 errout_alloc:
 356         if (balloc == 1)
 357                 kfree(cp.perfect);
 358         else if (balloc == 2)
 359                 kfree(cp.h);
 360 errout:
 361         tcf_exts_destroy(tp, &e);
 362         return err;
 363 }
 364
 365 static int
 366 tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 367                struct rtattr **tca, unsigned long *arg)
 368 {
 369         struct rtattr *opt = tca[TCA_OPTIONS-1];
 370         struct rtattr *tb[TCA_TCINDEX_MAX];
 371         struct tcindex_data *p = PRIV(tp);
 372         struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
 373
 374         DPRINTK("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
 375             "p %p,r %p,*arg 0x%lx\n",
 376             tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
 377
 378         if (!opt)
 379                 return 0;
 380
 381         if (rtattr_parse_nested(tb, TCA_TCINDEX_MAX, opt) < 0)
 382                 return -EINVAL;
 383
 384         return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE-1]);
 385 }
 386
 387
 388 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
 389 {
 390         struct tcindex_data *p = PRIV(tp);
 391         struct tcindex_filter *f,*next;
 392         int i;
 393
 394         DPRINTK("tcindex_walk(tp %p,walker %p),p %p\n",tp,walker,p);
 395         if (p->perfect) {
 396                 for (i = 0; i < p->hash; i++) {
 397                         if (!p->perfect[i].res.class)
 398                                 continue;
 399                         if (walker->count >= walker->skip) {
 400                                 if (walker->fn(tp,
 401                                     (unsigned long) (p->perfect+i), walker)
 402                                      < 0) {
 403                                         walker->stop = 1;
 404                                         return;
 405                                 }
 406                         }
 407                         walker->count++;
 408                 }
 409         }
 410         if (!p->h)
 411                 return;
 412         for (i = 0; i < p->hash; i++) {
 413                 for (f = p->h[i]; f; f = next) {
 414                         next = f->next;
 415                         if (walker->count >= walker->skip) {
 416                                 if (walker->fn(tp,(unsigned long) &f->result,
 417                                     walker) < 0) {
 418                                         walker->stop = 1;
 419                                         return;
 420                                 }
 421                         }
 422                         walker->count++;
 423                 }
 424         }
 425 }
 426
 427
 428 static int tcindex_destroy_element(struct tcf_proto *tp,
 429     unsigned long arg, struct tcf_walker *walker)
 430 {
 431         return __tcindex_delete(tp, arg, 0);
 432 }
 433
 434
 435 static void tcindex_destroy(struct tcf_proto *tp)
 436 {
 437         struct tcindex_data *p = PRIV(tp);
 438         struct tcf_walker walker;
 439
 440         DPRINTK("tcindex_destroy(tp %p),p %p\n",tp,p);
 441         walker.count = 0;
 442         walker.skip = 0;
 443         walker.fn = &tcindex_destroy_element;
 444         tcindex_walk(tp,&walker);
 445         if (p->perfect)
 446                 kfree(p->perfect);
 447         if (p->h)
 448                 kfree(p->h);
 449         kfree(p);
 450         tp->root = NULL;
 451 }
 452
 453
 454 static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
 455     struct sk_buff *skb, struct tcmsg *t)
 456 {
 457         struct tcindex_data *p = PRIV(tp);
 458         struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
 459         unsigned char *b = skb->tail;
 460         struct rtattr *rta;
 461
 462         DPRINTK("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
 463             tp,fh,skb,t,p,r,b);
 464         DPRINTK("p->perfect %p p->h %p\n",p->perfect,p->h);
 465         rta = (struct rtattr *) b;
 466         RTA_PUT(skb,TCA_OPTIONS,0,NULL);
 467         if (!fh) {
 468                 t->tcm_handle = ~0; /* whatever ... */
 469                 RTA_PUT(skb,TCA_TCINDEX_HASH,sizeof(p->hash),&p->hash);
 470                 RTA_PUT(skb,TCA_TCINDEX_MASK,sizeof(p->mask),&p->mask);
 471                 RTA_PUT(skb,TCA_TCINDEX_SHIFT,sizeof(p->shift),&p->shift);
 472                 RTA_PUT(skb,TCA_TCINDEX_FALL_THROUGH,sizeof(p->fall_through),
 473                     &p->fall_through);
 474                 rta->rta_len = skb->tail-b;
 475         } else {
 476                 if (p->perfect) {
 477                         t->tcm_handle = r-p->perfect;
 478                 } else {
 479                         struct tcindex_filter *f;
 480                         int i;
 481
 482                         t->tcm_handle = 0;
 483                         for (i = 0; !t->tcm_handle && i < p->hash; i++) {
 484                                 for (f = p->h[i]; !t->tcm_handle && f;
 485                                      f = f->next) {
 486                                         if (&f->result == r)
 487                                                 t->tcm_handle = f->key;
 488                                 }
 489                         }
 490                 }
 491                 DPRINTK("handle = %d\n",t->tcm_handle);
 492                 if (r->res.class)
 493                         RTA_PUT(skb, TCA_TCINDEX_CLASSID, 4, &r->res.classid);
 494
 495                 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
 496                         goto rtattr_failure;
 497                 rta->rta_len = skb->tail-b;
 498
 499                 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
 500                         goto rtattr_failure;
 501         }
 502
 503         return skb->len;
 504
 505 rtattr_failure:
 506         skb_trim(skb, b - skb->data);
 507         return -1;
 508 }
 509
 510 static struct tcf_proto_ops cls_tcindex_ops = {
 511         .next           =       NULL,
 512         .kind           =       "tcindex",
 513         .classify       =       tcindex_classify,
 514         .init           =       tcindex_init,
 515         .destroy        =       tcindex_destroy,
 516         .get            =       tcindex_get,
 517         .put            =       tcindex_put,
 518         .change         =       tcindex_change,
 519         .delete         =       tcindex_delete,
 520         .walk           =       tcindex_walk,
 521         .dump           =       tcindex_dump,
 522         .owner          =       THIS_MODULE,
 523 };
 524
 525 static int __init init_tcindex(void)
 526 {
 527         return register_tcf_proto_ops(&cls_tcindex_ops);
 528 }
 529
 530 static void __exit exit_tcindex(void)
 531 {
 532         unregister_tcf_proto_ops(&cls_tcindex_ops);
 533 }
 534
 535 module_init(init_tcindex)
 536 module_exit(exit_tcindex)
 537 MODULE_LICENSE("GPL");