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         union {
  61                 struct work_struct      work;
  62                 struct rcu_head         rcu;
  63         };
  64 };
  65
  66 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
  67
  68 static inline int route4_fastmap_hash(u32 id, int iif)
  69 {
  70         return id & 0xF;
  71 }
  72
  73 static DEFINE_SPINLOCK(fastmap_lock);
  74 static void
  75 route4_reset_fastmap(struct route4_head *head)
  76 {
  77         spin_lock_bh(&fastmap_lock);
  78         memset(head->fastmap, 0, sizeof(head->fastmap));
  79         spin_unlock_bh(&fastmap_lock);
  80 }
  81
  82 static void
  83 route4_set_fastmap(struct route4_head *head, u32 id, int iif,
  84                    struct route4_filter *f)
  85 {
  86         int h = route4_fastmap_hash(id, iif);
  87
  88         /* fastmap updates must look atomic to aling id, iff, filter */
  89         spin_lock_bh(&fastmap_lock);
  90         head->fastmap[h].id = id;
  91         head->fastmap[h].iif = iif;
  92         head->fastmap[h].filter = f;
  93         spin_unlock_bh(&fastmap_lock);
  94 }
  95
  96 static inline int route4_hash_to(u32 id)
  97 {
  98         return id & 0xFF;
  99 }
 100
 101 static inline int route4_hash_from(u32 id)
 102 {
 103         return (id >> 16) & 0xF;
 104 }
 105
 106 static inline int route4_hash_iif(int iif)
 107 {
 108         return 16 + ((iif >> 16) & 0xF);
 109 }
 110
 111 static inline int route4_hash_wild(void)
 112 {
 113         return 32;
 114 }
 115
 116 #define ROUTE4_APPLY_RESULT()                                   \
 117 {                                                               \
 118         *res = f->res;                                          \
 119         if (tcf_exts_has_actions(&f->exts)) {                   \
 120                 int r = tcf_exts_exec(skb, &f->exts, res);      \
 121                 if (r < 0) {                                    \
 122                         dont_cache = 1;                         \
 123                         continue;                               \
 124                 }                                               \
 125                 return r;                                       \
 126         } else if (!dont_cache)                                 \
 127                 route4_set_fastmap(head, id, iif, f);           \
 128         return 0;                                               \
 129 }
 130
 131 static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 132                            struct tcf_result *res)
 133 {
 134         struct route4_head *head = rcu_dereference_bh(tp->root);
 135         struct dst_entry *dst;
 136         struct route4_bucket *b;
 137         struct route4_filter *f;
 138         u32 id, h;
 139         int iif, dont_cache = 0;
 140
 141         dst = skb_dst(skb);
 142         if (!dst)
 143                 goto failure;
 144
 145         id = dst->tclassid;
 146
 147         iif = inet_iif(skb);
 148
 149         h = route4_fastmap_hash(id, iif);
 150
 151         spin_lock(&fastmap_lock);
 152         if (id == head->fastmap[h].id &&
 153             iif == head->fastmap[h].iif &&
 154             (f = head->fastmap[h].filter) != NULL) {
 155                 if (f == ROUTE4_FAILURE) {
 156                         spin_unlock(&fastmap_lock);
 157                         goto failure;
 158                 }
 159
 160                 *res = f->res;
 161                 spin_unlock(&fastmap_lock);
 162                 return 0;
 163         }
 164         spin_unlock(&fastmap_lock);
 165
 166         h = route4_hash_to(id);
 167
 168 restart:
 169         b = rcu_dereference_bh(head->table[h]);
 170         if (b) {
 171                 for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
 172                      f;
 173                      f = rcu_dereference_bh(f->next))
 174                         if (f->id == id)
 175                                 ROUTE4_APPLY_RESULT();
 176
 177                 for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
 178                      f;
 179                      f = rcu_dereference_bh(f->next))
 180                         if (f->iif == iif)
 181                                 ROUTE4_APPLY_RESULT();
 182
 183                 for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
 184                      f;
 185                      f = rcu_dereference_bh(f->next))
 186                         ROUTE4_APPLY_RESULT();
 187         }
 188         if (h < 256) {
 189                 h = 256;
 190                 id &= ~0xFFFF;
 191                 goto restart;
 192         }
 193
 194         if (!dont_cache)
 195                 route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
 196 failure:
 197         return -1;
 198 }
 199
 200 static inline u32 to_hash(u32 id)
 201 {
 202         u32 h = id & 0xFF;
 203
 204         if (id & 0x8000)
 205                 h += 256;
 206         return h;
 207 }
 208
 209 static inline u32 from_hash(u32 id)
 210 {
 211         id &= 0xFFFF;
 212         if (id == 0xFFFF)
 213                 return 32;
 214         if (!(id & 0x8000)) {
 215                 if (id > 255)
 216                         return 256;
 217                 return id & 0xF;
 218         }
 219         return 16 + (id & 0xF);
 220 }
 221
 222 static void *route4_get(struct tcf_proto *tp, u32 handle)
 223 {
 224         struct route4_head *head = rtnl_dereference(tp->root);
 225         struct route4_bucket *b;
 226         struct route4_filter *f;
 227         unsigned int h1, h2;
 228
 229         h1 = to_hash(handle);
 230         if (h1 > 256)
 231                 return NULL;
 232
 233         h2 = from_hash(handle >> 16);
 234         if (h2 > 32)
 235                 return NULL;
 236
 237         b = rtnl_dereference(head->table[h1]);
 238         if (b) {
 239                 for (f = rtnl_dereference(b->ht[h2]);
 240                      f;
 241                      f = rtnl_dereference(f->next))
 242                         if (f->handle == handle)
 243                                 return f;
 244         }
 245         return NULL;
 246 }
 247
 248 static int route4_init(struct tcf_proto *tp)
 249 {
 250         struct route4_head *head;
 251
 252         head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
 253         if (head == NULL)
 254                 return -ENOBUFS;
 255
 256         rcu_assign_pointer(tp->root, head);
 257         return 0;
 258 }
 259
 260 static void __route4_delete_filter(struct route4_filter *f)
 261 {
 262         tcf_exts_destroy(&f->exts);
 263         tcf_exts_put_net(&f->exts);
 264         kfree(f);
 265 }
 266
 267 static void route4_delete_filter_work(struct work_struct *work)
 268 {
 269         struct route4_filter *f = container_of(work, struct route4_filter, work);
 270
 271         rtnl_lock();
 272         __route4_delete_filter(f);
 273         rtnl_unlock();
 274 }
 275
 276 static void route4_delete_filter(struct rcu_head *head)
 277 {
 278         struct route4_filter *f = container_of(head, struct route4_filter, rcu);
 279
 280         INIT_WORK(&f->work, route4_delete_filter_work);
 281         tcf_queue_work(&f->work);
 282 }
 283
 284 static void route4_destroy(struct tcf_proto *tp)
 285 {
 286         struct route4_head *head = rtnl_dereference(tp->root);
 287         int h1, h2;
 288
 289         if (head == NULL)
 290                 return;
 291
 292         for (h1 = 0; h1 <= 256; h1++) {
 293                 struct route4_bucket *b;
 294
 295                 b = rtnl_dereference(head->table[h1]);
 296                 if (b) {
 297                         for (h2 = 0; h2 <= 32; h2++) {
 298                                 struct route4_filter *f;
 299
 300                                 while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
 301                                         struct route4_filter *next;
 302
 303                                         next = rtnl_dereference(f->next);
 304                                         RCU_INIT_POINTER(b->ht[h2], next);
 305                                         tcf_unbind_filter(tp, &f->res);
 306                                         if (tcf_exts_get_net(&f->exts))
 307                                                 call_rcu(&f->rcu, route4_delete_filter);
 308                                         else
 309                                                 __route4_delete_filter(f);
 310                                 }
 311                         }
 312                         RCU_INIT_POINTER(head->table[h1], NULL);
 313                         kfree_rcu(b, rcu);
 314                 }
 315         }
 316         kfree_rcu(head, rcu);
 317 }
 318
 319 static int route4_delete(struct tcf_proto *tp, void *arg, bool *last)
 320 {
 321         struct route4_head *head = rtnl_dereference(tp->root);
 322         struct route4_filter *f = arg;
 323         struct route4_filter __rcu **fp;
 324         struct route4_filter *nf;
 325         struct route4_bucket *b;
 326         unsigned int h = 0;
 327         int i, h1;
 328
 329         if (!head || !f)
 330                 return -EINVAL;
 331
 332         h = f->handle;
 333         b = f->bkt;
 334
 335         fp = &b->ht[from_hash(h >> 16)];
 336         for (nf = rtnl_dereference(*fp); nf;
 337              fp = &nf->next, nf = rtnl_dereference(*fp)) {
 338                 if (nf == f) {
 339                         /* unlink it */
 340                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 341
 342                         /* Remove any fastmap lookups that might ref filter
 343                          * notice we unlink'd the filter so we can't get it
 344                          * back in the fastmap.
 345                          */
 346                         route4_reset_fastmap(head);
 347
 348                         /* Delete it */
 349                         tcf_unbind_filter(tp, &f->res);
 350                         tcf_exts_get_net(&f->exts);
 351                         call_rcu(&f->rcu, route4_delete_filter);
 352
 353                         /* Strip RTNL protected tree */
 354                         for (i = 0; i <= 32; i++) {
 355                                 struct route4_filter *rt;
 356
 357                                 rt = rtnl_dereference(b->ht[i]);
 358                                 if (rt)
 359                                         goto out;
 360                         }
 361
 362                         /* OK, session has no flows */
 363                         RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
 364                         kfree_rcu(b, rcu);
 365                         break;
 366                 }
 367         }
 368
 369 out:
 370         *last = true;
 371         for (h1 = 0; h1 <= 256; h1++) {
 372                 if (rcu_access_pointer(head->table[h1])) {
 373                         *last = false;
 374                         break;
 375                 }
 376         }
 377
 378         return 0;
 379 }
 380
 381 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
 382         [TCA_ROUTE4_CLASSID]    = { .type = NLA_U32 },
 383         [TCA_ROUTE4_TO]         = { .type = NLA_U32 },
 384         [TCA_ROUTE4_FROM]       = { .type = NLA_U32 },
 385         [TCA_ROUTE4_IIF]        = { .type = NLA_U32 },
 386 };
 387
 388 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
 389                             unsigned long base, struct route4_filter *f,
 390                             u32 handle, struct route4_head *head,
 391                             struct nlattr **tb, struct nlattr *est, int new,
 392                             bool ovr)
 393 {
 394         u32 id = 0, to = 0, nhandle = 0x8000;
 395         struct route4_filter *fp;
 396         unsigned int h1;
 397         struct route4_bucket *b;
 398         int err;
 399
 400         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr);
 401         if (err < 0)
 402                 return err;
 403
 404         if (tb[TCA_ROUTE4_TO]) {
 405                 if (new && handle & 0x8000)
 406                         return -EINVAL;
 407                 to = nla_get_u32(tb[TCA_ROUTE4_TO]);
 408                 if (to > 0xFF)
 409                         return -EINVAL;
 410                 nhandle = to;
 411         }
 412
 413         if (tb[TCA_ROUTE4_FROM]) {
 414                 if (tb[TCA_ROUTE4_IIF])
 415                         return -EINVAL;
 416                 id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
 417                 if (id > 0xFF)
 418                         return -EINVAL;
 419                 nhandle |= id << 16;
 420         } else if (tb[TCA_ROUTE4_IIF]) {
 421                 id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
 422                 if (id > 0x7FFF)
 423                         return -EINVAL;
 424                 nhandle |= (id | 0x8000) << 16;
 425         } else
 426                 nhandle |= 0xFFFF << 16;
 427
 428         if (handle && new) {
 429                 nhandle |= handle & 0x7F00;
 430                 if (nhandle != handle)
 431                         return -EINVAL;
 432         }
 433
 434         if (!nhandle)
 435                 return -EINVAL;
 436
 437         h1 = to_hash(nhandle);
 438         b = rtnl_dereference(head->table[h1]);
 439         if (!b) {
 440                 b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
 441                 if (b == NULL)
 442                         return -ENOBUFS;
 443
 444                 rcu_assign_pointer(head->table[h1], b);
 445         } else {
 446                 unsigned int h2 = from_hash(nhandle >> 16);
 447
 448                 for (fp = rtnl_dereference(b->ht[h2]);
 449                      fp;
 450                      fp = rtnl_dereference(fp->next))
 451                         if (fp->handle == f->handle)
 452                                 return -EEXIST;
 453         }
 454
 455         if (tb[TCA_ROUTE4_TO])
 456                 f->id = to;
 457
 458         if (tb[TCA_ROUTE4_FROM])
 459                 f->id = to | id<<16;
 460         else if (tb[TCA_ROUTE4_IIF])
 461                 f->iif = id;
 462
 463         f->handle = nhandle;
 464         f->bkt = b;
 465         f->tp = tp;
 466
 467         if (tb[TCA_ROUTE4_CLASSID]) {
 468                 f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
 469                 tcf_bind_filter(tp, &f->res, base);
 470         }
 471
 472         return 0;
 473 }
 474
 475 static int route4_change(struct net *net, struct sk_buff *in_skb,
 476                          struct tcf_proto *tp, unsigned long base, u32 handle,
 477                          struct nlattr **tca, void **arg, bool ovr)
 478 {
 479         struct route4_head *head = rtnl_dereference(tp->root);
 480         struct route4_filter __rcu **fp;
 481         struct route4_filter *fold, *f1, *pfp, *f = NULL;
 482         struct route4_bucket *b;
 483         struct nlattr *opt = tca[TCA_OPTIONS];
 484         struct nlattr *tb[TCA_ROUTE4_MAX + 1];
 485         unsigned int h, th;
 486         int err;
 487         bool new = true;
 488
 489         if (!handle)
 490                 return -EINVAL;
 491
 492         if (opt == NULL)
 493                 return handle ? -EINVAL : 0;
 494
 495         err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy, NULL);
 496         if (err < 0)
 497                 return err;
 498
 499         fold = *arg;
 500         if (fold && handle && fold->handle != handle)
 501                         return -EINVAL;
 502
 503         err = -ENOBUFS;
 504         f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
 505         if (!f)
 506                 goto errout;
 507
 508         err = tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
 509         if (err < 0)
 510                 goto errout;
 511
 512         if (fold) {
 513                 f->id = fold->id;
 514                 f->iif = fold->iif;
 515                 f->handle = fold->handle;
 516
 517                 f->tp = fold->tp;
 518                 f->bkt = fold->bkt;
 519                 new = false;
 520         }
 521
 522         err = route4_set_parms(net, tp, base, f, handle, head, tb,
 523                                tca[TCA_RATE], new, ovr);
 524         if (err < 0)
 525                 goto errout;
 526
 527         h = from_hash(f->handle >> 16);
 528         fp = &f->bkt->ht[h];
 529         for (pfp = rtnl_dereference(*fp);
 530              (f1 = rtnl_dereference(*fp)) != NULL;
 531              fp = &f1->next)
 532                 if (f->handle < f1->handle)
 533                         break;
 534
 535         netif_keep_dst(qdisc_dev(tp->q));
 536         rcu_assign_pointer(f->next, f1);
 537         rcu_assign_pointer(*fp, f);
 538
 539         if (fold) {
 540                 th = to_hash(fold->handle);
 541                 h = from_hash(fold->handle >> 16);
 542                 b = rtnl_dereference(head->table[th]);
 543                 if (b) {
 544                         fp = &b->ht[h];
 545                         for (pfp = rtnl_dereference(*fp); pfp;
 546                              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 547                                 if (pfp == fold) {
 548                                         rcu_assign_pointer(*fp, fold->next);
 549                                         break;
 550                                 }
 551                         }
 552                 }
 553         }
 554
 555         route4_reset_fastmap(head);
 556         *arg = f;
 557         if (fold) {
 558                 tcf_unbind_filter(tp, &fold->res);
 559                 tcf_exts_get_net(&fold->exts);
 560                 call_rcu(&fold->rcu, route4_delete_filter);
 561         }
 562         return 0;
 563
 564 errout:
 565         if (f)
 566                 tcf_exts_destroy(&f->exts);
 567         kfree(f);
 568         return err;
 569 }
 570
 571 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 572 {
 573         struct route4_head *head = rtnl_dereference(tp->root);
 574         unsigned int h, h1;
 575
 576         if (head == NULL)
 577                 arg->stop = 1;
 578
 579         if (arg->stop)
 580                 return;
 581
 582         for (h = 0; h <= 256; h++) {
 583                 struct route4_bucket *b = rtnl_dereference(head->table[h]);
 584
 585                 if (b) {
 586                         for (h1 = 0; h1 <= 32; h1++) {
 587                                 struct route4_filter *f;
 588
 589                                 for (f = rtnl_dereference(b->ht[h1]);
 590                                      f;
 591                                      f = rtnl_dereference(f->next)) {
 592                                         if (arg->count < arg->skip) {
 593                                                 arg->count++;
 594                                                 continue;
 595                                         }
 596                                         if (arg->fn(tp, f, arg) < 0) {
 597                                                 arg->stop = 1;
 598                                                 return;
 599                                         }
 600                                         arg->count++;
 601                                 }
 602                         }
 603                 }
 604         }
 605 }
 606
 607 static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
 608                        struct sk_buff *skb, struct tcmsg *t)
 609 {
 610         struct route4_filter *f = fh;
 611         struct nlattr *nest;
 612         u32 id;
 613
 614         if (f == NULL)
 615                 return skb->len;
 616
 617         t->tcm_handle = f->handle;
 618
 619         nest = nla_nest_start(skb, TCA_OPTIONS);
 620         if (nest == NULL)
 621                 goto nla_put_failure;
 622
 623         if (!(f->handle & 0x8000)) {
 624                 id = f->id & 0xFF;
 625                 if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
 626                         goto nla_put_failure;
 627         }
 628         if (f->handle & 0x80000000) {
 629                 if ((f->handle >> 16) != 0xFFFF &&
 630                     nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
 631                         goto nla_put_failure;
 632         } else {
 633                 id = f->id >> 16;
 634                 if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
 635                         goto nla_put_failure;
 636         }
 637         if (f->res.classid &&
 638             nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
 639                 goto nla_put_failure;
 640
 641         if (tcf_exts_dump(skb, &f->exts) < 0)
 642                 goto nla_put_failure;
 643
 644         nla_nest_end(skb, nest);
 645
 646         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 647                 goto nla_put_failure;
 648
 649         return skb->len;
 650
 651 nla_put_failure:
 652         nla_nest_cancel(skb, nest);
 653         return -1;
 654 }
 655
 656 static void route4_bind_class(void *fh, u32 classid, unsigned long cl)
 657 {
 658         struct route4_filter *f = fh;
 659
 660         if (f && f->res.classid == classid)
 661                 f->res.class = cl;
 662 }
 663
 664 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
 665         .kind           =       "route",
 666         .classify       =       route4_classify,
 667         .init           =       route4_init,
 668         .destroy        =       route4_destroy,
 669         .get            =       route4_get,
 670         .change         =       route4_change,
 671         .delete         =       route4_delete,
 672         .walk           =       route4_walk,
 673         .dump           =       route4_dump,
 674         .bind_class     =       route4_bind_class,
 675         .owner          =       THIS_MODULE,
 676 };
 677
 678 static int __init init_route4(void)
 679 {
 680         return register_tcf_proto_ops(&cls_route4_ops);
 681 }
 682
 683 static void __exit exit_route4(void)
 684 {
 685         unregister_tcf_proto_ops(&cls_route4_ops);
 686 }
 687
 688 module_init(init_route4)
 689 module_exit(exit_route4)
 690 MODULE_LICENSE("GPL");