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 = kzalloc(sizeof(struct tcindex_data),GFP_KERNEL);
 152         if (!p)
 153                 return -ENOMEM;
 154
 155         p->mask = 0xffff;
 156         p->hash = DEFAULT_HASH_SIZE;
 157         p->fall_through = 1;
 158
 159         tp->root = p;
 160         return 0;
 161 }
 162
 163
 164 static int
 165 __tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
 166 {
 167         struct tcindex_data *p = PRIV(tp);
 168         struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
 169         struct tcindex_filter *f = NULL;
 170
 171         DPRINTK("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n",tp,arg,p,f);
 172         if (p->perfect) {
 173                 if (!r->res.class)
 174                         return -ENOENT;
 175         } else {
 176                 int i;
 177                 struct tcindex_filter **walk = NULL;
 178
 179                 for (i = 0; i < p->hash; i++)
 180                         for (walk = p->h+i; *walk; walk = &(*walk)->next)
 181                                 if (&(*walk)->result == r)
 182                                         goto found;
 183                 return -ENOENT;
 184
 185 found:
 186                 f = *walk;
 187                 if (lock)
 188                         tcf_tree_lock(tp);
 189                 *walk = f->next;
 190                 if (lock)
 191                         tcf_tree_unlock(tp);
 192         }
 193         tcf_unbind_filter(tp, &r->res);
 194         tcf_exts_destroy(tp, &r->exts);
 195         kfree(f);
 196         return 0;
 197 }
 198
 199 static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
 200 {
 201         return __tcindex_delete(tp, arg, 1);
 202 }
 203
 204 static inline int
 205 valid_perfect_hash(struct tcindex_data *p)
 206 {
 207         return  p->hash > (p->mask >> p->shift);
 208 }
 209
 210 static int
 211 tcindex_set_parms(struct tcf_proto *tp, unsigned long base, u32 handle,
 212                   struct tcindex_data *p, struct tcindex_filter_result *r,
 213                   struct rtattr **tb, struct rtattr *est)
 214 {
 215         int err, balloc = 0;
 216         struct tcindex_filter_result new_filter_result, *old_r = r;
 217         struct tcindex_filter_result cr;
 218         struct tcindex_data cp;
 219         struct tcindex_filter *f = NULL; /* make gcc behave */
 220         struct tcf_exts e;
 221
 222         err = tcf_exts_validate(tp, tb, est, &e, &tcindex_ext_map);
 223         if (err < 0)
 224                 return err;
 225
 226         memcpy(&cp, p, sizeof(cp));
 227         memset(&new_filter_result, 0, sizeof(new_filter_result));
 228
 229         if (old_r)
 230                 memcpy(&cr, r, sizeof(cr));
 231         else
 232                 memset(&cr, 0, sizeof(cr));
 233
 234         err = -EINVAL;
 235         if (tb[TCA_TCINDEX_HASH-1]) {
 236                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_HASH-1]) < sizeof(u32))
 237                         goto errout;
 238                 cp.hash = *(u32 *) RTA_DATA(tb[TCA_TCINDEX_HASH-1]);
 239         }
 240
 241         if (tb[TCA_TCINDEX_MASK-1]) {
 242                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_MASK-1]) < sizeof(u16))
 243                         goto errout;
 244                 cp.mask = *(u16 *) RTA_DATA(tb[TCA_TCINDEX_MASK-1]);
 245         }
 246
 247         if (tb[TCA_TCINDEX_SHIFT-1]) {
 248                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_SHIFT-1]) < sizeof(u16))
 249                         goto errout;
 250                 cp.shift = *(u16 *) RTA_DATA(tb[TCA_TCINDEX_SHIFT-1]);
 251         }
 252
 253         err = -EBUSY;
 254         /* Hash already allocated, make sure that we still meet the
 255          * requirements for the allocated hash.
 256          */
 257         if (cp.perfect) {
 258                 if (!valid_perfect_hash(&cp) ||
 259                     cp.hash > cp.alloc_hash)
 260                         goto errout;
 261         } else if (cp.h && cp.hash != cp.alloc_hash)
 262                 goto errout;
 263
 264         err = -EINVAL;
 265         if (tb[TCA_TCINDEX_FALL_THROUGH-1]) {
 266                 if (RTA_PAYLOAD(tb[TCA_TCINDEX_FALL_THROUGH-1]) < sizeof(u32))
 267                         goto errout;
 268                 cp.fall_through =
 269                         *(u32 *) RTA_DATA(tb[TCA_TCINDEX_FALL_THROUGH-1]);
 270         }
 271
 272         if (!cp.hash) {
 273                 /* Hash not specified, use perfect hash if the upper limit
 274                  * of the hashing index is below the threshold.
 275                  */
 276                 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
 277                         cp.hash = (cp.mask >> cp.shift)+1;
 278                 else
 279                         cp.hash = DEFAULT_HASH_SIZE;
 280         }
 281
 282         if (!cp.perfect && !cp.h)
 283                 cp.alloc_hash = cp.hash;
 284
 285         /* Note: this could be as restrictive as if (handle & ~(mask >> shift))
 286          * but then, we'd fail handles that may become valid after some future
 287          * mask change. While this is extremely unlikely to ever matter,
 288          * the check below is safer (and also more backwards-compatible).
 289          */
 290         if (cp.perfect || valid_perfect_hash(&cp))
 291                 if (handle >= cp.alloc_hash)
 292                         goto errout;
 293
 294
 295         err = -ENOMEM;
 296         if (!cp.perfect && !cp.h) {
 297                 if (valid_perfect_hash(&cp)) {
 298                         cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
 299                         if (!cp.perfect)
 300                                 goto errout;
 301                         balloc = 1;
 302                 } else {
 303                         cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
 304                         if (!cp.h)
 305                                 goto errout;
 306                         balloc = 2;
 307                 }
 308         }
 309
 310         if (cp.perfect)
 311                 r = cp.perfect + handle;
 312         else
 313                 r = tcindex_lookup(&cp, handle) ? : &new_filter_result;
 314
 315         if (r == &new_filter_result) {
 316                 f = kzalloc(sizeof(*f), GFP_KERNEL);
 317                 if (!f)
 318                         goto errout_alloc;
 319         }
 320
 321         if (tb[TCA_TCINDEX_CLASSID-1]) {
 322                 cr.res.classid = *(u32 *) RTA_DATA(tb[TCA_TCINDEX_CLASSID-1]);
 323                 tcf_bind_filter(tp, &cr.res, base);
 324         }
 325
 326         tcf_exts_change(tp, &cr.exts, &e);
 327
 328         tcf_tree_lock(tp);
 329         if (old_r && old_r != r)
 330                 memset(old_r, 0, sizeof(*old_r));
 331
 332         memcpy(p, &cp, sizeof(cp));
 333         memcpy(r, &cr, sizeof(cr));
 334
 335         if (r == &new_filter_result) {
 336                 struct tcindex_filter **fp;
 337
 338                 f->key = handle;
 339                 f->result = new_filter_result;
 340                 f->next = NULL;
 341                 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
 342                         /* nothing */;
 343                 *fp = f;
 344         }
 345         tcf_tree_unlock(tp);
 346
 347         return 0;
 348
 349 errout_alloc:
 350         if (balloc == 1)
 351                 kfree(cp.perfect);
 352         else if (balloc == 2)
 353                 kfree(cp.h);
 354 errout:
 355         tcf_exts_destroy(tp, &e);
 356         return err;
 357 }
 358
 359 static int
 360 tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 361                struct rtattr **tca, unsigned long *arg)
 362 {
 363         struct rtattr *opt = tca[TCA_OPTIONS-1];
 364         struct rtattr *tb[TCA_TCINDEX_MAX];
 365         struct tcindex_data *p = PRIV(tp);
 366         struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
 367
 368         DPRINTK("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
 369             "p %p,r %p,*arg 0x%lx\n",
 370             tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);
 371
 372         if (!opt)
 373                 return 0;
 374
 375         if (rtattr_parse_nested(tb, TCA_TCINDEX_MAX, opt) < 0)
 376                 return -EINVAL;
 377
 378         return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE-1]);
 379 }
 380
 381
 382 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
 383 {
 384         struct tcindex_data *p = PRIV(tp);
 385         struct tcindex_filter *f,*next;
 386         int i;
 387
 388         DPRINTK("tcindex_walk(tp %p,walker %p),p %p\n",tp,walker,p);
 389         if (p->perfect) {
 390                 for (i = 0; i < p->hash; i++) {
 391                         if (!p->perfect[i].res.class)
 392                                 continue;
 393                         if (walker->count >= walker->skip) {
 394                                 if (walker->fn(tp,
 395                                     (unsigned long) (p->perfect+i), walker)
 396                                      < 0) {
 397                                         walker->stop = 1;
 398                                         return;
 399                                 }
 400                         }
 401                         walker->count++;
 402                 }
 403         }
 404         if (!p->h)
 405                 return;
 406         for (i = 0; i < p->hash; i++) {
 407                 for (f = p->h[i]; f; f = next) {
 408                         next = f->next;
 409                         if (walker->count >= walker->skip) {
 410                                 if (walker->fn(tp,(unsigned long) &f->result,
 411                                     walker) < 0) {
 412                                         walker->stop = 1;
 413                                         return;
 414                                 }
 415                         }
 416                         walker->count++;
 417                 }
 418         }
 419 }
 420
 421
 422 static int tcindex_destroy_element(struct tcf_proto *tp,
 423     unsigned long arg, struct tcf_walker *walker)
 424 {
 425         return __tcindex_delete(tp, arg, 0);
 426 }
 427
 428
 429 static void tcindex_destroy(struct tcf_proto *tp)
 430 {
 431         struct tcindex_data *p = PRIV(tp);
 432         struct tcf_walker walker;
 433
 434         DPRINTK("tcindex_destroy(tp %p),p %p\n",tp,p);
 435         walker.count = 0;
 436         walker.skip = 0;
 437         walker.fn = &tcindex_destroy_element;
 438         tcindex_walk(tp,&walker);
 439         kfree(p->perfect);
 440         kfree(p->h);
 441         kfree(p);
 442         tp->root = NULL;
 443 }
 444
 445
 446 static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
 447     struct sk_buff *skb, struct tcmsg *t)
 448 {
 449         struct tcindex_data *p = PRIV(tp);
 450         struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
 451         unsigned char *b = skb->tail;
 452         struct rtattr *rta;
 453
 454         DPRINTK("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
 455             tp,fh,skb,t,p,r,b);
 456         DPRINTK("p->perfect %p p->h %p\n",p->perfect,p->h);
 457         rta = (struct rtattr *) b;
 458         RTA_PUT(skb,TCA_OPTIONS,0,NULL);
 459         if (!fh) {
 460                 t->tcm_handle = ~0; /* whatever ... */
 461                 RTA_PUT(skb,TCA_TCINDEX_HASH,sizeof(p->hash),&p->hash);
 462                 RTA_PUT(skb,TCA_TCINDEX_MASK,sizeof(p->mask),&p->mask);
 463                 RTA_PUT(skb,TCA_TCINDEX_SHIFT,sizeof(p->shift),&p->shift);
 464                 RTA_PUT(skb,TCA_TCINDEX_FALL_THROUGH,sizeof(p->fall_through),
 465                     &p->fall_through);
 466                 rta->rta_len = skb->tail-b;
 467         } else {
 468                 if (p->perfect) {
 469                         t->tcm_handle = r-p->perfect;
 470                 } else {
 471                         struct tcindex_filter *f;
 472                         int i;
 473
 474                         t->tcm_handle = 0;
 475                         for (i = 0; !t->tcm_handle && i < p->hash; i++) {
 476                                 for (f = p->h[i]; !t->tcm_handle && f;
 477                                      f = f->next) {
 478                                         if (&f->result == r)
 479                                                 t->tcm_handle = f->key;
 480                                 }
 481                         }
 482                 }
 483                 DPRINTK("handle = %d\n",t->tcm_handle);
 484                 if (r->res.class)
 485                         RTA_PUT(skb, TCA_TCINDEX_CLASSID, 4, &r->res.classid);
 486
 487                 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
 488                         goto rtattr_failure;
 489                 rta->rta_len = skb->tail-b;
 490
 491                 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
 492                         goto rtattr_failure;
 493         }
 494
 495         return skb->len;
 496
 497 rtattr_failure:
 498         skb_trim(skb, b - skb->data);
 499         return -1;
 500 }
 501
 502 static struct tcf_proto_ops cls_tcindex_ops = {
 503         .next           =       NULL,
 504         .kind           =       "tcindex",
 505         .classify       =       tcindex_classify,
 506         .init           =       tcindex_init,
 507         .destroy        =       tcindex_destroy,
 508         .get            =       tcindex_get,
 509         .put            =       tcindex_put,
 510         .change         =       tcindex_change,
 511         .delete         =       tcindex_delete,
 512         .walk           =       tcindex_walk,
 513         .dump           =       tcindex_dump,
 514         .owner          =       THIS_MODULE,
 515 };
 516
 517 static int __init init_tcindex(void)
 518 {
 519         return register_tcf_proto_ops(&cls_tcindex_ops);
 520 }
 521
 522 static void __exit exit_tcindex(void)
 523 {
 524         unregister_tcf_proto_ops(&cls_tcindex_ops);
 525 }
 526
 527 module_init(init_tcindex)
 528 module_exit(exit_tcindex)
 529 MODULE_LICENSE("GPL");