net/sched/cls_route.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/cls_route.c        ROUTE4 classifier.
   4  *
   5  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/slab.h>
  10 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #include <linux/string.h>
  13 #include <linux/errno.h>
  14 #include <linux/skbuff.h>
  15 #include <net/dst.h>
  16 #include <net/route.h>
  17 #include <net/netlink.h>
  18 #include <net/act_api.h>
  19 #include <net/pkt_cls.h>
  20 #include <net/tc_wrapper.h>
  21
  22 /*
  23  * 1. For now we assume that route tags < 256.
  24  *    It allows to use direct table lookups, instead of hash tables.
  25  * 2. For now we assume that "from TAG" and "fromdev DEV" statements
  26  *    are mutually  exclusive.
  27  * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
  28  */
  29 struct route4_fastmap {
  30         struct route4_filter            *filter;
  31         u32                             id;
  32         int                             iif;
  33 };
  34
  35 struct route4_head {
  36         struct route4_fastmap           fastmap[16];
  37         struct route4_bucket __rcu      *table[256 + 1];
  38         struct rcu_head                 rcu;
  39 };
  40
  41 struct route4_bucket {
  42         /* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
  43         struct route4_filter __rcu      *ht[16 + 16 + 1];
  44         struct rcu_head                 rcu;
  45 };
  46
  47 struct route4_filter {
  48         struct route4_filter __rcu      *next;
  49         u32                     id;
  50         int                     iif;
  51
  52         struct tcf_result       res;
  53         struct tcf_exts         exts;
  54         u32                     handle;
  55         struct route4_bucket    *bkt;
  56         struct tcf_proto        *tp;
  57         struct rcu_work         rwork;
  58 };
  59
  60 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
  61
  62 static inline int route4_fastmap_hash(u32 id, int iif)
  63 {
  64         return id & 0xF;
  65 }
  66
  67 static DEFINE_SPINLOCK(fastmap_lock);
  68 static void
  69 route4_reset_fastmap(struct route4_head *head)
  70 {
  71         spin_lock_bh(&fastmap_lock);
  72         memset(head->fastmap, 0, sizeof(head->fastmap));
  73         spin_unlock_bh(&fastmap_lock);
  74 }
  75
  76 static void
  77 route4_set_fastmap(struct route4_head *head, u32 id, int iif,
  78                    struct route4_filter *f)
  79 {
  80         int h = route4_fastmap_hash(id, iif);
  81
  82         /* fastmap updates must look atomic to aling id, iff, filter */
  83         spin_lock_bh(&fastmap_lock);
  84         head->fastmap[h].id = id;
  85         head->fastmap[h].iif = iif;
  86         head->fastmap[h].filter = f;
  87         spin_unlock_bh(&fastmap_lock);
  88 }
  89
  90 static inline int route4_hash_to(u32 id)
  91 {
  92         return id & 0xFF;
  93 }
  94
  95 static inline int route4_hash_from(u32 id)
  96 {
  97         return (id >> 16) & 0xF;
  98 }
  99
 100 static inline int route4_hash_iif(int iif)
 101 {
 102         return 16 + ((iif >> 16) & 0xF);
 103 }
 104
 105 static inline int route4_hash_wild(void)
 106 {
 107         return 32;
 108 }
 109
 110 #define ROUTE4_APPLY_RESULT()                                   \
 111 {                                                               \
 112         *res = f->res;                                          \
 113         if (tcf_exts_has_actions(&f->exts)) {                   \
 114                 int r = tcf_exts_exec(skb, &f->exts, res);      \
 115                 if (r < 0) {                                    \
 116                         dont_cache = 1;                         \
 117                         continue;                               \
 118                 }                                               \
 119                 return r;                                       \
 120         } else if (!dont_cache)                                 \
 121                 route4_set_fastmap(head, id, iif, f);           \
 122         return 0;                                               \
 123 }
 124
 125 TC_INDIRECT_SCOPE int route4_classify(struct sk_buff *skb,
 126                                       const struct tcf_proto *tp,
 127                                       struct tcf_result *res)
 128 {
 129         struct route4_head *head = rcu_dereference_bh(tp->root);
 130         struct dst_entry *dst;
 131         struct route4_bucket *b;
 132         struct route4_filter *f;
 133         u32 id, h;
 134         int iif, dont_cache = 0;
 135
 136         dst = skb_dst(skb);
 137         if (!dst)
 138                 goto failure;
 139
 140         id = dst->tclassid;
 141
 142         iif = inet_iif(skb);
 143
 144         h = route4_fastmap_hash(id, iif);
 145
 146         spin_lock(&fastmap_lock);
 147         if (id == head->fastmap[h].id &&
 148             iif == head->fastmap[h].iif &&
 149             (f = head->fastmap[h].filter) != NULL) {
 150                 if (f == ROUTE4_FAILURE) {
 151                         spin_unlock(&fastmap_lock);
 152                         goto failure;
 153                 }
 154
 155                 *res = f->res;
 156                 spin_unlock(&fastmap_lock);
 157                 return 0;
 158         }
 159         spin_unlock(&fastmap_lock);
 160
 161         h = route4_hash_to(id);
 162
 163 restart:
 164         b = rcu_dereference_bh(head->table[h]);
 165         if (b) {
 166                 for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
 167                      f;
 168                      f = rcu_dereference_bh(f->next))
 169                         if (f->id == id)
 170                                 ROUTE4_APPLY_RESULT();
 171
 172                 for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
 173                      f;
 174                      f = rcu_dereference_bh(f->next))
 175                         if (f->iif == iif)
 176                                 ROUTE4_APPLY_RESULT();
 177
 178                 for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
 179                      f;
 180                      f = rcu_dereference_bh(f->next))
 181                         ROUTE4_APPLY_RESULT();
 182         }
 183         if (h < 256) {
 184                 h = 256;
 185                 id &= ~0xFFFF;
 186                 goto restart;
 187         }
 188
 189         if (!dont_cache)
 190                 route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
 191 failure:
 192         return -1;
 193 }
 194
 195 static inline u32 to_hash(u32 id)
 196 {
 197         u32 h = id & 0xFF;
 198
 199         if (id & 0x8000)
 200                 h += 256;
 201         return h;
 202 }
 203
 204 static inline u32 from_hash(u32 id)
 205 {
 206         id &= 0xFFFF;
 207         if (id == 0xFFFF)
 208                 return 32;
 209         if (!(id & 0x8000)) {
 210                 if (id > 255)
 211                         return 256;
 212                 return id & 0xF;
 213         }
 214         return 16 + (id & 0xF);
 215 }
 216
 217 static void *route4_get(struct tcf_proto *tp, u32 handle)
 218 {
 219         struct route4_head *head = rtnl_dereference(tp->root);
 220         struct route4_bucket *b;
 221         struct route4_filter *f;
 222         unsigned int h1, h2;
 223
 224         h1 = to_hash(handle);
 225         if (h1 > 256)
 226                 return NULL;
 227
 228         h2 = from_hash(handle >> 16);
 229         if (h2 > 32)
 230                 return NULL;
 231
 232         b = rtnl_dereference(head->table[h1]);
 233         if (b) {
 234                 for (f = rtnl_dereference(b->ht[h2]);
 235                      f;
 236                      f = rtnl_dereference(f->next))
 237                         if (f->handle == handle)
 238                                 return f;
 239         }
 240         return NULL;
 241 }
 242
 243 static int route4_init(struct tcf_proto *tp)
 244 {
 245         struct route4_head *head;
 246
 247         head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
 248         if (head == NULL)
 249                 return -ENOBUFS;
 250
 251         rcu_assign_pointer(tp->root, head);
 252         return 0;
 253 }
 254
 255 static void __route4_delete_filter(struct route4_filter *f)
 256 {
 257         tcf_exts_destroy(&f->exts);
 258         tcf_exts_put_net(&f->exts);
 259         kfree(f);
 260 }
 261
 262 static void route4_delete_filter_work(struct work_struct *work)
 263 {
 264         struct route4_filter *f = container_of(to_rcu_work(work),
 265                                                struct route4_filter,
 266                                                rwork);
 267         rtnl_lock();
 268         __route4_delete_filter(f);
 269         rtnl_unlock();
 270 }
 271
 272 static void route4_queue_work(struct route4_filter *f)
 273 {
 274         tcf_queue_work(&f->rwork, route4_delete_filter_work);
 275 }
 276
 277 static void route4_destroy(struct tcf_proto *tp, bool rtnl_held,
 278                            struct netlink_ext_ack *extack)
 279 {
 280         struct route4_head *head = rtnl_dereference(tp->root);
 281         int h1, h2;
 282
 283         if (head == NULL)
 284                 return;
 285
 286         for (h1 = 0; h1 <= 256; h1++) {
 287                 struct route4_bucket *b;
 288
 289                 b = rtnl_dereference(head->table[h1]);
 290                 if (b) {
 291                         for (h2 = 0; h2 <= 32; h2++) {
 292                                 struct route4_filter *f;
 293
 294                                 while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
 295                                         struct route4_filter *next;
 296
 297                                         next = rtnl_dereference(f->next);
 298                                         RCU_INIT_POINTER(b->ht[h2], next);
 299                                         tcf_unbind_filter(tp, &f->res);
 300                                         if (tcf_exts_get_net(&f->exts))
 301                                                 route4_queue_work(f);
 302                                         else
 303                                                 __route4_delete_filter(f);
 304                                 }
 305                         }
 306                         RCU_INIT_POINTER(head->table[h1], NULL);
 307                         kfree_rcu(b, rcu);
 308                 }
 309         }
 310         kfree_rcu(head, rcu);
 311 }
 312
 313 static int route4_delete(struct tcf_proto *tp, void *arg, bool *last,
 314                          bool rtnl_held, struct netlink_ext_ack *extack)
 315 {
 316         struct route4_head *head = rtnl_dereference(tp->root);
 317         struct route4_filter *f = arg;
 318         struct route4_filter __rcu **fp;
 319         struct route4_filter *nf;
 320         struct route4_bucket *b;
 321         unsigned int h = 0;
 322         int i, h1;
 323
 324         if (!head || !f)
 325                 return -EINVAL;
 326
 327         h = f->handle;
 328         b = f->bkt;
 329
 330         fp = &b->ht[from_hash(h >> 16)];
 331         for (nf = rtnl_dereference(*fp); nf;
 332              fp = &nf->next, nf = rtnl_dereference(*fp)) {
 333                 if (nf == f) {
 334                         /* unlink it */
 335                         RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 336
 337                         /* Remove any fastmap lookups that might ref filter
 338                          * notice we unlink'd the filter so we can't get it
 339                          * back in the fastmap.
 340                          */
 341                         route4_reset_fastmap(head);
 342
 343                         /* Delete it */
 344                         tcf_unbind_filter(tp, &f->res);
 345                         tcf_exts_get_net(&f->exts);
 346                         tcf_queue_work(&f->rwork, route4_delete_filter_work);
 347
 348                         /* Strip RTNL protected tree */
 349                         for (i = 0; i <= 32; i++) {
 350                                 struct route4_filter *rt;
 351
 352                                 rt = rtnl_dereference(b->ht[i]);
 353                                 if (rt)
 354                                         goto out;
 355                         }
 356
 357                         /* OK, session has no flows */
 358                         RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
 359                         kfree_rcu(b, rcu);
 360                         break;
 361                 }
 362         }
 363
 364 out:
 365         *last = true;
 366         for (h1 = 0; h1 <= 256; h1++) {
 367                 if (rcu_access_pointer(head->table[h1])) {
 368                         *last = false;
 369                         break;
 370                 }
 371         }
 372
 373         return 0;
 374 }
 375
 376 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
 377         [TCA_ROUTE4_CLASSID]    = { .type = NLA_U32 },
 378         [TCA_ROUTE4_TO]         = NLA_POLICY_MAX(NLA_U32, 0xFF),
 379         [TCA_ROUTE4_FROM]       = NLA_POLICY_MAX(NLA_U32, 0xFF),
 380         [TCA_ROUTE4_IIF]        = NLA_POLICY_MAX(NLA_U32, 0x7FFF),
 381 };
 382
 383 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
 384                             unsigned long base, struct route4_filter *f,
 385                             u32 handle, struct route4_head *head,
 386                             struct nlattr **tb, struct nlattr *est, int new,
 387                             u32 flags, struct netlink_ext_ack *extack)
 388 {
 389         u32 id = 0, to = 0, nhandle = 0x8000;
 390         struct route4_filter *fp;
 391         unsigned int h1;
 392         struct route4_bucket *b;
 393         int err;
 394
 395         err = tcf_exts_validate(net, tp, tb, est, &f->exts, flags, extack);
 396         if (err < 0)
 397                 return err;
 398
 399         if (tb[TCA_ROUTE4_TO]) {
 400                 if (new && handle & 0x8000) {
 401                         NL_SET_ERR_MSG(extack, "Invalid handle");
 402                         return -EINVAL;
 403                 }
 404                 to = nla_get_u32(tb[TCA_ROUTE4_TO]);
 405                 nhandle = to;
 406         }
 407
 408         if (tb[TCA_ROUTE4_FROM] && tb[TCA_ROUTE4_IIF]) {
 409                 NL_SET_ERR_MSG_ATTR(extack, tb[TCA_ROUTE4_FROM],
 410                                     "'from' and 'fromif' are mutually exclusive");
 411                 return -EINVAL;
 412         }
 413
 414         if (tb[TCA_ROUTE4_FROM]) {
 415                 id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
 416                 nhandle |= id << 16;
 417         } else if (tb[TCA_ROUTE4_IIF]) {
 418                 id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
 419                 nhandle |= (id | 0x8000) << 16;
 420         } else
 421                 nhandle |= 0xFFFF << 16;
 422
 423         if (handle && new) {
 424                 nhandle |= handle & 0x7F00;
 425                 if (nhandle != handle) {
 426                         NL_SET_ERR_MSG_FMT(extack,
 427                                            "Handle mismatch constructed: %x (expected: %x)",
 428                                            handle, nhandle);
 429                         return -EINVAL;
 430                 }
 431         }
 432
 433         if (!nhandle) {
 434                 NL_SET_ERR_MSG(extack, "Replacing with handle of 0 is invalid");
 435                 return -EINVAL;
 436         }
 437
 438         h1 = to_hash(nhandle);
 439         b = rtnl_dereference(head->table[h1]);
 440         if (!b) {
 441                 b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
 442                 if (b == NULL)
 443                         return -ENOBUFS;
 444
 445                 rcu_assign_pointer(head->table[h1], b);
 446         } else {
 447                 unsigned int h2 = from_hash(nhandle >> 16);
 448
 449                 for (fp = rtnl_dereference(b->ht[h2]);
 450                      fp;
 451                      fp = rtnl_dereference(fp->next))
 452                         if (fp->handle == f->handle)
 453                                 return -EEXIST;
 454         }
 455
 456         if (tb[TCA_ROUTE4_TO])
 457                 f->id = to;
 458
 459         if (tb[TCA_ROUTE4_FROM])
 460                 f->id = to | id<<16;
 461         else if (tb[TCA_ROUTE4_IIF])
 462                 f->iif = id;
 463
 464         f->handle = nhandle;
 465         f->bkt = b;
 466         f->tp = tp;
 467
 468         if (tb[TCA_ROUTE4_CLASSID]) {
 469                 f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
 470                 tcf_bind_filter(tp, &f->res, base);
 471         }
 472
 473         return 0;
 474 }
 475
 476 static int route4_change(struct net *net, struct sk_buff *in_skb,
 477                          struct tcf_proto *tp, unsigned long base, u32 handle,
 478                          struct nlattr **tca, void **arg, u32 flags,
 479                          struct netlink_ext_ack *extack)
 480 {
 481         struct route4_head *head = rtnl_dereference(tp->root);
 482         struct route4_filter __rcu **fp;
 483         struct route4_filter *fold, *f1, *pfp, *f = NULL;
 484         struct route4_bucket *b;
 485         struct nlattr *tb[TCA_ROUTE4_MAX + 1];
 486         unsigned int h, th;
 487         int err;
 488         bool new = true;
 489
 490         if (!handle) {
 491                 NL_SET_ERR_MSG(extack, "Creating with handle of 0 is invalid");
 492                 return -EINVAL;
 493         }
 494
 495         if (NL_REQ_ATTR_CHECK(extack, NULL, tca, TCA_OPTIONS)) {
 496                 NL_SET_ERR_MSG_MOD(extack, "Missing options");
 497                 return -EINVAL;
 498         }
 499
 500         err = nla_parse_nested_deprecated(tb, TCA_ROUTE4_MAX, tca[TCA_OPTIONS],
 501                                           route4_policy, NULL);
 502         if (err < 0)
 503                 return err;
 504
 505         fold = *arg;
 506         if (fold && fold->handle != handle)
 507                         return -EINVAL;
 508
 509         err = -ENOBUFS;
 510         f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
 511         if (!f)
 512                 goto errout;
 513
 514         err = tcf_exts_init(&f->exts, net, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
 515         if (err < 0)
 516                 goto errout;
 517
 518         if (fold) {
 519                 f->id = fold->id;
 520                 f->iif = fold->iif;
 521                 f->handle = fold->handle;
 522
 523                 f->tp = fold->tp;
 524                 f->bkt = fold->bkt;
 525                 new = false;
 526         }
 527
 528         err = route4_set_parms(net, tp, base, f, handle, head, tb,
 529                                tca[TCA_RATE], new, flags, extack);
 530         if (err < 0)
 531                 goto errout;
 532
 533         h = from_hash(f->handle >> 16);
 534         fp = &f->bkt->ht[h];
 535         for (pfp = rtnl_dereference(*fp);
 536              (f1 = rtnl_dereference(*fp)) != NULL;
 537              fp = &f1->next)
 538                 if (f->handle < f1->handle)
 539                         break;
 540
 541         tcf_block_netif_keep_dst(tp->chain->block);
 542         rcu_assign_pointer(f->next, f1);
 543         rcu_assign_pointer(*fp, f);
 544
 545         if (fold) {
 546                 th = to_hash(fold->handle);
 547                 h = from_hash(fold->handle >> 16);
 548                 b = rtnl_dereference(head->table[th]);
 549                 if (b) {
 550                         fp = &b->ht[h];
 551                         for (pfp = rtnl_dereference(*fp); pfp;
 552                              fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 553                                 if (pfp == fold) {
 554                                         rcu_assign_pointer(*fp, fold->next);
 555                                         break;
 556                                 }
 557                         }
 558                 }
 559         }
 560
 561         route4_reset_fastmap(head);
 562         *arg = f;
 563         if (fold) {
 564                 tcf_unbind_filter(tp, &fold->res);
 565                 tcf_exts_get_net(&fold->exts);
 566                 tcf_queue_work(&fold->rwork, route4_delete_filter_work);
 567         }
 568         return 0;
 569
 570 errout:
 571         if (f)
 572                 tcf_exts_destroy(&f->exts);
 573         kfree(f);
 574         return err;
 575 }
 576
 577 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
 578                         bool rtnl_held)
 579 {
 580         struct route4_head *head = rtnl_dereference(tp->root);
 581         unsigned int h, h1;
 582
 583         if (head == NULL || arg->stop)
 584                 return;
 585
 586         for (h = 0; h <= 256; h++) {
 587                 struct route4_bucket *b = rtnl_dereference(head->table[h]);
 588
 589                 if (b) {
 590                         for (h1 = 0; h1 <= 32; h1++) {
 591                                 struct route4_filter *f;
 592
 593                                 for (f = rtnl_dereference(b->ht[h1]);
 594                                      f;
 595                                      f = rtnl_dereference(f->next)) {
 596                                         if (!tc_cls_stats_dump(tp, arg, f))
 597                                                 return;
 598                                 }
 599                         }
 600                 }
 601         }
 602 }
 603
 604 static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
 605                        struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
 606 {
 607         struct route4_filter *f = fh;
 608         struct nlattr *nest;
 609         u32 id;
 610
 611         if (f == NULL)
 612                 return skb->len;
 613
 614         t->tcm_handle = f->handle;
 615
 616         nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
 617         if (nest == NULL)
 618                 goto nla_put_failure;
 619
 620         if (!(f->handle & 0x8000)) {
 621                 id = f->id & 0xFF;
 622                 if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
 623                         goto nla_put_failure;
 624         }
 625         if (f->handle & 0x80000000) {
 626                 if ((f->handle >> 16) != 0xFFFF &&
 627                     nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
 628                         goto nla_put_failure;
 629         } else {
 630                 id = f->id >> 16;
 631                 if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
 632                         goto nla_put_failure;
 633         }
 634         if (f->res.classid &&
 635             nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
 636                 goto nla_put_failure;
 637
 638         if (tcf_exts_dump(skb, &f->exts) < 0)
 639                 goto nla_put_failure;
 640
 641         nla_nest_end(skb, nest);
 642
 643         if (tcf_exts_dump_stats(skb, &f->exts) < 0)
 644                 goto nla_put_failure;
 645
 646         return skb->len;
 647
 648 nla_put_failure:
 649         nla_nest_cancel(skb, nest);
 650         return -1;
 651 }
 652
 653 static void route4_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
 654                               unsigned long base)
 655 {
 656         struct route4_filter *f = fh;
 657
 658         tc_cls_bind_class(classid, cl, q, &f->res, base);
 659 }
 660
 661 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
 662         .kind           =       "route",
 663         .classify       =       route4_classify,
 664         .init           =       route4_init,
 665         .destroy        =       route4_destroy,
 666         .get            =       route4_get,
 667         .change         =       route4_change,
 668         .delete         =       route4_delete,
 669         .walk           =       route4_walk,
 670         .dump           =       route4_dump,
 671         .bind_class     =       route4_bind_class,
 672         .owner          =       THIS_MODULE,
 673 };
 674 MODULE_ALIAS_NET_CLS("route");
 675
 676 static int __init init_route4(void)
 677 {
 678         return register_tcf_proto_ops(&cls_route4_ops);
 679 }
 680
 681 static void __exit exit_route4(void)
 682 {
 683         unregister_tcf_proto_ops(&cls_route4_ops);
 684 }
 685
 686 module_init(init_route4)
 687 module_exit(exit_route4)
 688 MODULE_DESCRIPTION("Routing table realm based TC classifier");
 689 MODULE_LICENSE("GPL");