net/sched/cls_route.c

   1 /*
   2  * net/sched/cls_route.c        ROUTE4 classifier.
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/types.h>
  15 #include <linux/kernel.h>
  16 #include <linux/string.h>
  17 #include <linux/errno.h>
  18 #include <linux/skbuff.h>
  19 #include <net/dst.h>
  20 #include <net/route.h>
  21 #include <net/netlink.h>
  22 #include <net/act_api.h>
  23 #include <net/pkt_cls.h>
  24
  25 /*
  26  * 1. For now we assume that route tags < 256.
  27  *    It allows to use direct table lookups, instead of hash tables.
  28  * 2. For now we assume that "from TAG" and "fromdev DEV" statements
  29  *    are mutually  exclusive.
  30  * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
  31  */
  32 struct route4_fastmap {
  33         struct route4_filter            *filter;
  34         u32                             id;
  35         int                             iif;
  36 };
  37
  38 struct route4_head {
  39         struct route4_fastmap           fastmap[16];
  40         struct route4_bucket __rcu      *table[256 + 1];
  41         struct rcu_head                 rcu;
  42 };
  43
  44 struct route4_bucket {
  45         /* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
  46         struct route4_filter __rcu      *ht[16 + 16 + 1];
  47         struct rcu_head                 rcu;
  48 };
  49
  50 struct route4_filter {
  51         struct route4_filter __rcu      *next;
  52         u32                     id;
  53         int                     iif;
  54
  55         struct tcf_result       res;
  56         struct tcf_exts         exts;
  57         u32                     handle;
  58         struct route4_bucket    *bkt;
  59         struct tcf_proto        *tp;
  60         struct rcu_head         rcu;
  61 };
  62
  63 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
  64
  65 static inline int route4_fastmap_hash(u32 id, int iif)
  66 {
  67         return id & 0xF;
  68 }
  69
  70 static DEFINE_SPINLOCK(fastmap_lock);
  71 static void
  72 route4_reset_fastmap(struct route4_head *head)
  73 {
  74         spin_lock_bh(&fastmap_lock);
  75         memset(head->fastmap, 0, sizeof(head->fastmap));
  76         spin_unlock_bh(&fastmap_lock);
  77 }
  78
  79 static void
  80 route4_set_fastmap(struct route4_head *head, u32 id, int iif,
  81                    struct route4_filter *f)
  82 {
  83         int h = route4_fastmap_hash(id, iif);
  84
  85         /* fastmap updates must look atomic to aling id, iff, filter */
  86         spin_lock_bh(&fastmap_lock);
  87         head->fastmap[h].id = id;
  88         head->fastmap[h].iif = iif;
  89         head->fastmap[h].filter = f;
  90         spin_unlock_bh(&fastmap_lock);
  91 }
  92
  93 static inline int route4_hash_to(u32 id)
  94 {
  95         return id & 0xFF;
  96 }
  97
  98 static inline int route4_hash_from(u32 id)
  99 {
 100         return (id >> 16) & 0xF;
 101 }
 102
 103 static inline int route4_hash_iif(int iif)
 104 {
 105         return 16 + ((iif >> 16) & 0xF);
 106 }
 107
 108 static inline int route4_hash_wild(void)
 109 {
 110         return 32;
 111 }
 112
 113 #define ROUTE4_APPLY_RESULT()                                   \
 114 {                                                               \
 115         *res = f->res;                                          \
 116         if (tcf_exts_has_actions(&f->exts)) {                   \
 117                 int r = tcf_exts_exec(skb, &f->exts, res);      \
 118                 if (r < 0) {                                    \
 119                         dont_cache = 1;                         \
 120                         continue;                               \
 121                 }                                               \
 122                 return r;                                       \
 123         } else if (!dont_cache)                                 \
 124                 route4_set_fastmap(head, id, iif, f);           \
 125         return 0;                                               \
 126 }
 127
 128 static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 129                            struct tcf_result *res)
 130 {
 131         struct route4_head *head = rcu_dereference_bh(tp->root);
 132         struct dst_entry *dst;
 133         struct route4_bucket *b;
 134         struct route4_filter *f;
 135         u32 id, h;
 136         int iif, dont_cache = 0;
 137
 138         dst = skb_dst(skb);
 139         if (!dst)
 140                 goto failure;
 141
 142         id = dst->tclassid;
 143
 144         iif = inet_iif(skb);
 145
 146         h = route4_fastmap_hash(id, iif);
 147
 148         spin_lock(&fastmap_lock);
 149         if (id == head->fastmap[h].id &&
 150             iif == head->fastmap[h].iif &&
 151             (f = head->fastmap[h].filter) != NULL) {
 152                 if (f == ROUTE4_FAILURE) {
 153                         spin_unlock(&fastmap_lock);
 154                         goto failure;
 155                 }
 156
 157                 *res = f->res;
 158                 spin_unlock(&fastmap_lock);
 159                 return 0;
 160         }
 161         spin_unlock(&fastmap_lock);
 162
 163         h = route4_hash_to(id);
 164
 165 restart:
 166         b = rcu_dereference_bh(head->table[h]);
 167         if (b) {
 168                 for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
 169                      f;
 170                      f = rcu_dereference_bh(f->next))
 171                         if (f->id == id)
 172                                 ROUTE4_APPLY_RESULT();
 173
 174                 for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
 175                      f;
 176                      f = rcu_dereference_bh(f->next))
 177                         if (f->iif == iif)
 178                                 ROUTE4_APPLY_RESULT();
 179
 180                 for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
 181                      f;
 182                      f = rcu_dereference_bh(f->next))
 183                         ROUTE4_APPLY_RESULT();
 184         }
 185         if (h < 256) {
 186                 h = 256;
 187                 id &= ~0xFFFF;
 188                 goto restart;
 189         }
 190
 191         if (!dont_cache)
 192                 route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
 193 failure:
 194         return -1;
 195 }
 196
 197 static inline u32 to_hash(u32 id)
 198 {
 199         u32 h = id & 0xFF;
 200
 201         if (id & 0x8000)
 202                 h += 256;
 203         return h;
 204 }
 205
 206 static inline u32 from_hash(u32 id)
 207 {
 208         id &= 0xFFFF;
 209         if (id == 0xFFFF)
 210                 return 32;
 211         if (!(id & 0x8000)) {
 212                 if (id > 255)
 213                         return 256;
 214                 return id & 0xF;
 215         }
 216         return 16 + (id & 0xF);
 217 }
 218
 219 static void *route4_get(struct tcf_proto *tp, u32 handle)
 220 {
 221         struct route4_head *head = rtnl_dereference(tp->root);
 222         struct route4_bucket *b;
 223         struct route4_filter *f;
 224         unsigned int h1, h2;
 225
 226         h1 = to_hash(handle);
 227         if (h1 > 256)
 228                 return NULL;
 229
 230         h2 = from_hash(handle >> 16);
 231         if (h2 > 32)
 232                 return NULL;
 233
 234         b = rtnl_dereference(head->table[h1]);
 235         if (b) {
 236                 for (f = rtnl_dereference(b->ht[h2]);
 237                      f;
 238                      f = rtnl_dereference(f->next))
 239                         if (f->handle == handle)
 240                                 return f;
 241         }
 242         return NULL;
 243 }
 244
 245 static int route4_init(struct tcf_proto *tp)
 246 {
 247         struct route4_head *head;
 248
 249         head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
 250         if (head == NULL)
 251                 return -ENOBUFS;
 252
 253         rcu_assign_pointer(tp->root, head);
 254         return 0;
 255 }
 256
 257 static void route4_delete_filter(struct rcu_head *head)
 258 {
 259         struct route4_filter *f = container_of(head, struct route4_filter, rcu);
 260
 261         tcf_exts_destroy(&f->exts);
 262         kfree(f);
 263 }
 264
 265 static void route4_destroy(struct tcf_proto *tp)
 266 {
 267         struct route4_head *head = rtnl_dereference(tp->root);
 268         int h1, h2;
 269
 270         if (head == NULL)
 271                 return;
 272
 273         for (h1 = 0; h1 <= 256; h1++) {
 274                 struct route4_bucket *b;
 275
 276                 b = rtnl_dereference(head->table[h1]);
 277                 if (b) {
 278                         for (h2 = 0; h2 <= 32; h2++) {
 279                                 struct route4_filter *f;
 280
 281                                 while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
 282                                         struct route4_filter *next;
 283
 284                                         next = rtnl_dereference(f->next);
 285                                         RCU_INIT_POINTER(b->ht[h2], next);
 286                                         tcf_unbind_filter(tp, &f->res);
 287                                         call_rcu(&f->rcu, route4_delete_filter);
 288                                 }
 289                         }
 290                         RCU_INIT_POINTER(head->table[h1], NULL);
 291                         kfree_rcu(b, rcu);
 292                 }
 293         }
 294         kfree_rcu(head, rcu);
 295 }
 296
 297 static int route4_delete(struct tcf_proto *tp, void *arg, bool *last)
 298 {
 299         struct route4_head *head = rtnl_dereference(tp->root);
 300         struct route4_filter *f = arg;
 301         struct route4_filter __rcu **fp;
 302         struct route4_filter *nf;
 303         struct route4_bucket *b;
 304         unsigned int h = 0;
 305         int i, h1;
 306
 307         if (!head || !f)
 308                 return -EINVAL;
 309
 310         h = f->handle;
 311         b = f->bkt;
 312
 313         fp = &b->ht[from_hash(h >> 16)];
 314         for (nf = rtnl_dereference(*fp); nf;
 315              fp = &nf->next, nf = rtnl_dereference(*fp)) {
 316                 if (nf == f) {
 317                         /* unlink it */
 318                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 319
 320                         /* Remove any fastmap lookups that might ref filter
 321                          * notice we unlink'd the filter so we can't get it
 322                          * back in the fastmap.
 323                          */
 324                         route4_reset_fastmap(head);
 325
 326                         /* Delete it */
 327                         tcf_unbind_filter(tp, &f->res);
 328                         call_rcu(&f->rcu, route4_delete_filter);
 329
 330                         /* Strip RTNL protected tree */
 331                         for (i = 0; i <= 32; i++) {
 332                                 struct route4_filter *rt;
 333
 334                                 rt = rtnl_dereference(b->ht[i]);
 335                                 if (rt)
 336                                         goto out;
 337                         }
 338
 339                         /* OK, session has no flows */
 340                         RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
 341                         kfree_rcu(b, rcu);
 342                         break;
 343                 }
 344         }
 345
 346 out:
 347         *last = true;
 348         for (h1 = 0; h1 <= 256; h1++) {
 349                 if (rcu_access_pointer(head->table[h1])) {
 350                         *last = false;
 351                         break;
 352                 }
 353         }
 354
 355         return 0;
 356 }
 357
 358 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
 359         [TCA_ROUTE4_CLASSID]    = { .type = NLA_U32 },
 360         [TCA_ROUTE4_TO]         = { .type = NLA_U32 },
 361         [TCA_ROUTE4_FROM]       = { .type = NLA_U32 },
 362         [TCA_ROUTE4_IIF]        = { .type = NLA_U32 },
 363 };
 364
 365 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
 366                             unsigned long base, struct route4_filter *f,
 367                             u32 handle, struct route4_head *head,
 368                             struct nlattr **tb, struct nlattr *est, int new,
 369                             bool ovr)
 370 {
 371         u32 id = 0, to = 0, nhandle = 0x8000;
 372         struct route4_filter *fp;
 373         unsigned int h1;
 374         struct route4_bucket *b;
 375         int err;
 376
 377         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr);
 378         if (err < 0)
 379                 return err;
 380
 381         if (tb[TCA_ROUTE4_TO]) {
 382                 if (new && handle & 0x8000)
 383                         return -EINVAL;
 384                 to = nla_get_u32(tb[TCA_ROUTE4_TO]);
 385                 if (to > 0xFF)
 386                         return -EINVAL;
 387                 nhandle = to;
 388         }
 389
 390         if (tb[TCA_ROUTE4_FROM]) {
 391                 if (tb[TCA_ROUTE4_IIF])
 392                         return -EINVAL;
 393                 id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
 394                 if (id > 0xFF)
 395                         return -EINVAL;
 396                 nhandle |= id << 16;
 397         } else if (tb[TCA_ROUTE4_IIF]) {
 398                 id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
 399                 if (id > 0x7FFF)
 400                         return -EINVAL;
 401                 nhandle |= (id | 0x8000) << 16;
 402         } else
 403                 nhandle |= 0xFFFF << 16;
 404
 405         if (handle && new) {
 406                 nhandle |= handle & 0x7F00;
 407                 if (nhandle != handle)
 408                         return -EINVAL;
 409         }
 410
 411         h1 = to_hash(nhandle);
 412         b = rtnl_dereference(head->table[h1]);
 413         if (!b) {
 414                 b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
 415                 if (b == NULL)
 416                         return -ENOBUFS;
 417
 418                 rcu_assign_pointer(head->table[h1], b);
 419         } else {
 420                 unsigned int h2 = from_hash(nhandle >> 16);
 421
 422                 for (fp = rtnl_dereference(b->ht[h2]);
 423                      fp;
 424                      fp = rtnl_dereference(fp->next))
 425                         if (fp->handle == f->handle)
 426                                 return -EEXIST;
 427         }
 428
 429         if (tb[TCA_ROUTE4_TO])
 430                 f->id = to;
 431
 432         if (tb[TCA_ROUTE4_FROM])
 433                 f->id = to | id<<16;
 434         else if (tb[TCA_ROUTE4_IIF])
 435                 f->iif = id;
 436
 437         f->handle = nhandle;
 438         f->bkt = b;
 439         f->tp = tp;
 440
 441         if (tb[TCA_ROUTE4_CLASSID]) {
 442                 f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
 443                 tcf_bind_filter(tp, &f->res, base);
 444         }
 445
 446         return 0;
 447 }
 448
 449 static int route4_change(struct net *net, struct sk_buff *in_skb,
 450                          struct tcf_proto *tp, unsigned long base, u32 handle,
 451                          struct nlattr **tca, void **arg, bool ovr)
 452 {
 453         struct route4_head *head = rtnl_dereference(tp->root);
 454         struct route4_filter __rcu **fp;
 455         struct route4_filter *fold, *f1, *pfp, *f = NULL;
 456         struct route4_bucket *b;
 457         struct nlattr *opt = tca[TCA_OPTIONS];
 458         struct nlattr *tb[TCA_ROUTE4_MAX + 1];
 459         unsigned int h, th;
 460         int err;
 461         bool new = true;
 462
 463         if (opt == NULL)
 464                 return handle ? -EINVAL : 0;
 465
 466         err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy, NULL);
 467         if (err < 0)
 468                 return err;
 469
 470         fold = *arg;
 471         if (fold && handle && fold->handle != handle)
 472                         return -EINVAL;
 473
 474         err = -ENOBUFS;
 475         f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
 476         if (!f)
 477                 goto errout;
 478
 479         err = tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
 480         if (err < 0)
 481                 goto errout;
 482
 483         if (fold) {
 484                 f->id = fold->id;
 485                 f->iif = fold->iif;
 486                 f->res = fold->res;
 487                 f->handle = fold->handle;
 488
 489                 f->tp = fold->tp;
 490                 f->bkt = fold->bkt;
 491                 new = false;
 492         }
 493
 494         err = route4_set_parms(net, tp, base, f, handle, head, tb,
 495                                tca[TCA_RATE], new, ovr);
 496         if (err < 0)
 497                 goto errout;
 498
 499         h = from_hash(f->handle >> 16);
 500         fp = &f->bkt->ht[h];
 501         for (pfp = rtnl_dereference(*fp);
 502              (f1 = rtnl_dereference(*fp)) != NULL;
 503              fp = &f1->next)
 504                 if (f->handle < f1->handle)
 505                         break;
 506
 507         netif_keep_dst(qdisc_dev(tp->q));
 508         rcu_assign_pointer(f->next, f1);
 509         rcu_assign_pointer(*fp, f);
 510
 511         if (fold && fold->handle && f->handle != fold->handle) {
 512                 th = to_hash(fold->handle);
 513                 h = from_hash(fold->handle >> 16);
 514                 b = rtnl_dereference(head->table[th]);
 515                 if (b) {
 516                         fp = &b->ht[h];
 517                         for (pfp = rtnl_dereference(*fp); pfp;
 518                              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 519                                 if (pfp == f) {
 520                                         *fp = f->next;
 521                                         break;
 522                                 }
 523                         }
 524                 }
 525         }
 526
 527         route4_reset_fastmap(head);
 528         *arg = f;
 529         if (fold) {
 530                 tcf_unbind_filter(tp, &fold->res);
 531                 call_rcu(&fold->rcu, route4_delete_filter);
 532         }
 533         return 0;
 534
 535 errout:
 536         if (f)
 537                 tcf_exts_destroy(&f->exts);
 538         kfree(f);
 539         return err;
 540 }
 541
 542 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 543 {
 544         struct route4_head *head = rtnl_dereference(tp->root);
 545         unsigned int h, h1;
 546
 547         if (head == NULL)
 548                 arg->stop = 1;
 549
 550         if (arg->stop)
 551                 return;
 552
 553         for (h = 0; h <= 256; h++) {
 554                 struct route4_bucket *b = rtnl_dereference(head->table[h]);
 555
 556                 if (b) {
 557                         for (h1 = 0; h1 <= 32; h1++) {
 558                                 struct route4_filter *f;
 559
 560                                 for (f = rtnl_dereference(b->ht[h1]);
 561                                      f;
 562                                      f = rtnl_dereference(f->next)) {
 563                                         if (arg->count < arg->skip) {
 564                                                 arg->count++;
 565                                                 continue;
 566                                         }
 567                                         if (arg->fn(tp, f, arg) < 0) {
 568                                                 arg->stop = 1;
 569                                                 return;
 570                                         }
 571                                         arg->count++;
 572                                 }
 573                         }
 574                 }
 575         }
 576 }
 577
 578 static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
 579                        struct sk_buff *skb, struct tcmsg *t)
 580 {
 581         struct route4_filter *f = fh;
 582         struct nlattr *nest;
 583         u32 id;
 584
 585         if (f == NULL)
 586                 return skb->len;
 587
 588         t->tcm_handle = f->handle;
 589
 590         nest = nla_nest_start(skb, TCA_OPTIONS);
 591         if (nest == NULL)
 592                 goto nla_put_failure;
 593
 594         if (!(f->handle & 0x8000)) {
 595                 id = f->id & 0xFF;
 596                 if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
 597                         goto nla_put_failure;
 598         }
 599         if (f->handle & 0x80000000) {
 600                 if ((f->handle >> 16) != 0xFFFF &&
 601                     nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
 602                         goto nla_put_failure;
 603         } else {
 604                 id = f->id >> 16;
 605                 if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
 606                         goto nla_put_failure;
 607         }
 608         if (f->res.classid &&
 609             nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
 610                 goto nla_put_failure;
 611
 612         if (tcf_exts_dump(skb, &f->exts) < 0)
 613                 goto nla_put_failure;
 614
 615         nla_nest_end(skb, nest);
 616
 617         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 618                 goto nla_put_failure;
 619
 620         return skb->len;
 621
 622 nla_put_failure:
 623         nla_nest_cancel(skb, nest);
 624         return -1;
 625 }
 626
 627 static void route4_bind_class(void *fh, u32 classid, unsigned long cl)
 628 {
 629         struct route4_filter *f = fh;
 630
 631         if (f && f->res.classid == classid)
 632                 f->res.class = cl;
 633 }
 634
 635 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
 636         .kind           =       "route",
 637         .classify       =       route4_classify,
 638         .init           =       route4_init,
 639         .destroy        =       route4_destroy,
 640         .get            =       route4_get,
 641         .change         =       route4_change,
 642         .delete         =       route4_delete,
 643         .walk           =       route4_walk,
 644         .dump           =       route4_dump,
 645         .bind_class     =       route4_bind_class,
 646         .owner          =       THIS_MODULE,
 647 };
 648
 649 static int __init init_route4(void)
 650 {
 651         return register_tcf_proto_ops(&cls_route4_ops);
 652 }
 653
 654 static void __exit exit_route4(void)
 655 {
 656         unregister_tcf_proto_ops(&cls_route4_ops);
 657 }
 658
 659 module_init(init_route4)
 660 module_exit(exit_route4)
 661 MODULE_LICENSE("GPL");