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_work         rwork;
  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 route4_filter *f)
 258 {
 259         tcf_exts_destroy(&f->exts);
 260         tcf_exts_put_net(&f->exts);
 261         kfree(f);
 262 }
 263
 264 static void route4_delete_filter_work(struct work_struct *work)
 265 {
 266         struct route4_filter *f = container_of(to_rcu_work(work),
 267                                                struct route4_filter,
 268                                                rwork);
 269         rtnl_lock();
 270         __route4_delete_filter(f);
 271         rtnl_unlock();
 272 }
 273
 274 static void route4_queue_work(struct route4_filter *f)
 275 {
 276         tcf_queue_work(&f->rwork, route4_delete_filter_work);
 277 }
 278
 279 static void route4_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 280 {
 281         struct route4_head *head = rtnl_dereference(tp->root);
 282         int h1, h2;
 283
 284         if (head == NULL)
 285                 return;
 286
 287         for (h1 = 0; h1 <= 256; h1++) {
 288                 struct route4_bucket *b;
 289
 290                 b = rtnl_dereference(head->table[h1]);
 291                 if (b) {
 292                         for (h2 = 0; h2 <= 32; h2++) {
 293                                 struct route4_filter *f;
 294
 295                                 while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
 296                                         struct route4_filter *next;
 297
 298                                         next = rtnl_dereference(f->next);
 299                                         RCU_INIT_POINTER(b->ht[h2], next);
 300                                         tcf_unbind_filter(tp, &f->res);
 301                                         if (tcf_exts_get_net(&f->exts))
 302                                                 route4_queue_work(f);
 303                                         else
 304                                                 __route4_delete_filter(f);
 305                                 }
 306                         }
 307                         RCU_INIT_POINTER(head->table[h1], NULL);
 308                         kfree_rcu(b, rcu);
 309                 }
 310         }
 311         kfree_rcu(head, rcu);
 312 }
 313
 314 static int route4_delete(struct tcf_proto *tp, void *arg, bool *last,
 315                          struct netlink_ext_ack *extack)
 316 {
 317         struct route4_head *head = rtnl_dereference(tp->root);
 318         struct route4_filter *f = arg;
 319         struct route4_filter __rcu **fp;
 320         struct route4_filter *nf;
 321         struct route4_bucket *b;
 322         unsigned int h = 0;
 323         int i, h1;
 324
 325         if (!head || !f)
 326                 return -EINVAL;
 327
 328         h = f->handle;
 329         b = f->bkt;
 330
 331         fp = &b->ht[from_hash(h >> 16)];
 332         for (nf = rtnl_dereference(*fp); nf;
 333              fp = &nf->next, nf = rtnl_dereference(*fp)) {
 334                 if (nf == f) {
 335                         /* unlink it */
 336                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 337
 338                         /* Remove any fastmap lookups that might ref filter
 339                          * notice we unlink'd the filter so we can't get it
 340                          * back in the fastmap.
 341                          */
 342                         route4_reset_fastmap(head);
 343
 344                         /* Delete it */
 345                         tcf_unbind_filter(tp, &f->res);
 346                         tcf_exts_get_net(&f->exts);
 347                         tcf_queue_work(&f->rwork, route4_delete_filter_work);
 348
 349                         /* Strip RTNL protected tree */
 350                         for (i = 0; i <= 32; i++) {
 351                                 struct route4_filter *rt;
 352
 353                                 rt = rtnl_dereference(b->ht[i]);
 354                                 if (rt)
 355                                         goto out;
 356                         }
 357
 358                         /* OK, session has no flows */
 359                         RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
 360                         kfree_rcu(b, rcu);
 361                         break;
 362                 }
 363         }
 364
 365 out:
 366         *last = true;
 367         for (h1 = 0; h1 <= 256; h1++) {
 368                 if (rcu_access_pointer(head->table[h1])) {
 369                         *last = false;
 370                         break;
 371                 }
 372         }
 373
 374         return 0;
 375 }
 376
 377 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
 378         [TCA_ROUTE4_CLASSID]    = { .type = NLA_U32 },
 379         [TCA_ROUTE4_TO]         = { .type = NLA_U32 },
 380         [TCA_ROUTE4_FROM]       = { .type = NLA_U32 },
 381         [TCA_ROUTE4_IIF]        = { .type = NLA_U32 },
 382 };
 383
 384 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
 385                             unsigned long base, struct route4_filter *f,
 386                             u32 handle, struct route4_head *head,
 387                             struct nlattr **tb, struct nlattr *est, int new,
 388                             bool ovr, struct netlink_ext_ack *extack)
 389 {
 390         u32 id = 0, to = 0, nhandle = 0x8000;
 391         struct route4_filter *fp;
 392         unsigned int h1;
 393         struct route4_bucket *b;
 394         int err;
 395
 396         err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, extack);
 397         if (err < 0)
 398                 return err;
 399
 400         if (tb[TCA_ROUTE4_TO]) {
 401                 if (new && handle & 0x8000)
 402                         return -EINVAL;
 403                 to = nla_get_u32(tb[TCA_ROUTE4_TO]);
 404                 if (to > 0xFF)
 405                         return -EINVAL;
 406                 nhandle = to;
 407         }
 408
 409         if (tb[TCA_ROUTE4_FROM]) {
 410                 if (tb[TCA_ROUTE4_IIF])
 411                         return -EINVAL;
 412                 id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
 413                 if (id > 0xFF)
 414                         return -EINVAL;
 415                 nhandle |= id << 16;
 416         } else if (tb[TCA_ROUTE4_IIF]) {
 417                 id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
 418                 if (id > 0x7FFF)
 419                         return -EINVAL;
 420                 nhandle |= (id | 0x8000) << 16;
 421         } else
 422                 nhandle |= 0xFFFF << 16;
 423
 424         if (handle && new) {
 425                 nhandle |= handle & 0x7F00;
 426                 if (nhandle != handle)
 427                         return -EINVAL;
 428         }
 429
 430         if (!nhandle) {
 431                 NL_SET_ERR_MSG(extack, "Replacing with handle of 0 is invalid");
 432                 return -EINVAL;
 433         }
 434
 435         h1 = to_hash(nhandle);
 436         b = rtnl_dereference(head->table[h1]);
 437         if (!b) {
 438                 b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
 439                 if (b == NULL)
 440                         return -ENOBUFS;
 441
 442                 rcu_assign_pointer(head->table[h1], b);
 443         } else {
 444                 unsigned int h2 = from_hash(nhandle >> 16);
 445
 446                 for (fp = rtnl_dereference(b->ht[h2]);
 447                      fp;
 448                      fp = rtnl_dereference(fp->next))
 449                         if (fp->handle == f->handle)
 450                                 return -EEXIST;
 451         }
 452
 453         if (tb[TCA_ROUTE4_TO])
 454                 f->id = to;
 455
 456         if (tb[TCA_ROUTE4_FROM])
 457                 f->id = to | id<<16;
 458         else if (tb[TCA_ROUTE4_IIF])
 459                 f->iif = id;
 460
 461         f->handle = nhandle;
 462         f->bkt = b;
 463         f->tp = tp;
 464
 465         if (tb[TCA_ROUTE4_CLASSID]) {
 466                 f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
 467                 tcf_bind_filter(tp, &f->res, base);
 468         }
 469
 470         return 0;
 471 }
 472
 473 static int route4_change(struct net *net, struct sk_buff *in_skb,
 474                          struct tcf_proto *tp, unsigned long base, u32 handle,
 475                          struct nlattr **tca, void **arg, bool ovr,
 476                          struct netlink_ext_ack *extack)
 477 {
 478         struct route4_head *head = rtnl_dereference(tp->root);
 479         struct route4_filter __rcu **fp;
 480         struct route4_filter *fold, *f1, *pfp, *f = NULL;
 481         struct route4_bucket *b;
 482         struct nlattr *opt = tca[TCA_OPTIONS];
 483         struct nlattr *tb[TCA_ROUTE4_MAX + 1];
 484         unsigned int h, th;
 485         int err;
 486         bool new = true;
 487
 488         if (!handle) {
 489                 NL_SET_ERR_MSG(extack, "Creating with handle of 0 is invalid");
 490                 return -EINVAL;
 491         }
 492
 493         if (opt == NULL)
 494                 return handle ? -EINVAL : 0;
 495
 496         err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy, NULL);
 497         if (err < 0)
 498                 return err;
 499
 500         fold = *arg;
 501         if (fold && handle && fold->handle != handle)
 502                         return -EINVAL;
 503
 504         err = -ENOBUFS;
 505         f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
 506         if (!f)
 507                 goto errout;
 508
 509         err = tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
 510         if (err < 0)
 511                 goto errout;
 512
 513         if (fold) {
 514                 f->id = fold->id;
 515                 f->iif = fold->iif;
 516                 f->handle = fold->handle;
 517
 518                 f->tp = fold->tp;
 519                 f->bkt = fold->bkt;
 520                 new = false;
 521         }
 522
 523         err = route4_set_parms(net, tp, base, f, handle, head, tb,
 524                                tca[TCA_RATE], new, ovr, extack);
 525         if (err < 0)
 526                 goto errout;
 527
 528         h = from_hash(f->handle >> 16);
 529         fp = &f->bkt->ht[h];
 530         for (pfp = rtnl_dereference(*fp);
 531              (f1 = rtnl_dereference(*fp)) != NULL;
 532              fp = &f1->next)
 533                 if (f->handle < f1->handle)
 534                         break;
 535
 536         tcf_block_netif_keep_dst(tp->chain->block);
 537         rcu_assign_pointer(f->next, f1);
 538         rcu_assign_pointer(*fp, f);
 539
 540         if (fold) {
 541                 th = to_hash(fold->handle);
 542                 h = from_hash(fold->handle >> 16);
 543                 b = rtnl_dereference(head->table[th]);
 544                 if (b) {
 545                         fp = &b->ht[h];
 546                         for (pfp = rtnl_dereference(*fp); pfp;
 547                              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 548                                 if (pfp == fold) {
 549                                         rcu_assign_pointer(*fp, fold->next);
 550                                         break;
 551                                 }
 552                         }
 553                 }
 554         }
 555
 556         route4_reset_fastmap(head);
 557         *arg = f;
 558         if (fold) {
 559                 tcf_unbind_filter(tp, &fold->res);
 560                 tcf_exts_get_net(&fold->exts);
 561                 tcf_queue_work(&fold->rwork, route4_delete_filter_work);
 562         }
 563         return 0;
 564
 565 errout:
 566         if (f)
 567                 tcf_exts_destroy(&f->exts);
 568         kfree(f);
 569         return err;
 570 }
 571
 572 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 573 {
 574         struct route4_head *head = rtnl_dereference(tp->root);
 575         unsigned int h, h1;
 576
 577         if (head == NULL)
 578                 arg->stop = 1;
 579
 580         if (arg->stop)
 581                 return;
 582
 583         for (h = 0; h <= 256; h++) {
 584                 struct route4_bucket *b = rtnl_dereference(head->table[h]);
 585
 586                 if (b) {
 587                         for (h1 = 0; h1 <= 32; h1++) {
 588                                 struct route4_filter *f;
 589
 590                                 for (f = rtnl_dereference(b->ht[h1]);
 591                                      f;
 592                                      f = rtnl_dereference(f->next)) {
 593                                         if (arg->count < arg->skip) {
 594                                                 arg->count++;
 595                                                 continue;
 596                                         }
 597                                         if (arg->fn(tp, f, arg) < 0) {
 598                                                 arg->stop = 1;
 599                                                 return;
 600                                         }
 601                                         arg->count++;
 602                                 }
 603                         }
 604                 }
 605         }
 606 }
 607
 608 static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
 609                        struct sk_buff *skb, struct tcmsg *t)
 610 {
 611         struct route4_filter *f = fh;
 612         struct nlattr *nest;
 613         u32 id;
 614
 615         if (f == NULL)
 616                 return skb->len;
 617
 618         t->tcm_handle = f->handle;
 619
 620         nest = nla_nest_start(skb, TCA_OPTIONS);
 621         if (nest == NULL)
 622                 goto nla_put_failure;
 623
 624         if (!(f->handle & 0x8000)) {
 625                 id = f->id & 0xFF;
 626                 if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
 627                         goto nla_put_failure;
 628         }
 629         if (f->handle & 0x80000000) {
 630                 if ((f->handle >> 16) != 0xFFFF &&
 631                     nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
 632                         goto nla_put_failure;
 633         } else {
 634                 id = f->id >> 16;
 635                 if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
 636                         goto nla_put_failure;
 637         }
 638         if (f->res.classid &&
 639             nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
 640                 goto nla_put_failure;
 641
 642         if (tcf_exts_dump(skb, &f->exts) < 0)
 643                 goto nla_put_failure;
 644
 645         nla_nest_end(skb, nest);
 646
 647         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 648                 goto nla_put_failure;
 649
 650         return skb->len;
 651
 652 nla_put_failure:
 653         nla_nest_cancel(skb, nest);
 654         return -1;
 655 }
 656
 657 static void route4_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
 658                               unsigned long base)
 659 {
 660         struct route4_filter *f = fh;
 661
 662         if (f && f->res.classid == classid) {
 663                 if (cl)
 664                         __tcf_bind_filter(q, &f->res, base);
 665                 else
 666                         __tcf_unbind_filter(q, &f->res);
 667         }
 668 }
 669
 670 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
 671         .kind           =       "route",
 672         .classify       =       route4_classify,
 673         .init           =       route4_init,
 674         .destroy        =       route4_destroy,
 675         .get            =       route4_get,
 676         .change         =       route4_change,
 677         .delete         =       route4_delete,
 678         .walk           =       route4_walk,
 679         .dump           =       route4_dump,
 680         .bind_class     =       route4_bind_class,
 681         .owner          =       THIS_MODULE,
 682 };
 683
 684 static int __init init_route4(void)
 685 {
 686         return register_tcf_proto_ops(&cls_route4_ops);
 687 }
 688
 689 static void __exit exit_route4(void)
 690 {
 691         unregister_tcf_proto_ops(&cls_route4_ops);
 692 }
 693
 694 module_init(init_route4)
 695 module_exit(exit_route4)
 696 MODULE_LICENSE("GPL");