net/ipv6/ip6_fib.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Linux INET6 implementation
   4  *      Forwarding Information Database
   5  *
   6  *      Authors:
   7  *      Pedro Roque             <roque@di.fc.ul.pt>
   8  *
   9  *      Changes:
  10  *      Yuji SEKIYA @USAGI:     Support default route on router node;
  11  *                              remove ip6_null_entry from the top of
  12  *                              routing table.
  13  *      Ville Nuorvala:         Fixed routing subtrees.
  14  */
  15
  16 #define pr_fmt(fmt) "IPv6: " fmt
  17
  18 #include <linux/bpf.h>
  19 #include <linux/errno.h>
  20 #include <linux/types.h>
  21 #include <linux/net.h>
  22 #include <linux/route.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/in6.h>
  25 #include <linux/init.h>
  26 #include <linux/list.h>
  27 #include <linux/slab.h>
  28
  29 #include <net/ip.h>
  30 #include <net/ipv6.h>
  31 #include <net/ndisc.h>
  32 #include <net/addrconf.h>
  33 #include <net/lwtunnel.h>
  34 #include <net/fib_notifier.h>
  35
  36 #include <net/ip_fib.h>
  37 #include <net/ip6_fib.h>
  38 #include <net/ip6_route.h>
  39
  40 static struct kmem_cache *fib6_node_kmem __read_mostly;
  41
  42 struct fib6_cleaner {
  43         struct fib6_walker w;
  44         struct net *net;
  45         int (*func)(struct fib6_info *, void *arg);
  46         int sernum;
  47         void *arg;
  48         bool skip_notify;
  49 };
  50
  51 #ifdef CONFIG_IPV6_SUBTREES
  52 #define FWS_INIT FWS_S
  53 #else
  54 #define FWS_INIT FWS_L
  55 #endif
  56
  57 static struct fib6_info *fib6_find_prefix(struct net *net,
  58                                          struct fib6_table *table,
  59                                          struct fib6_node *fn);
  60 static struct fib6_node *fib6_repair_tree(struct net *net,
  61                                           struct fib6_table *table,
  62                                           struct fib6_node *fn);
  63 static int fib6_walk(struct net *net, struct fib6_walker *w);
  64 static int fib6_walk_continue(struct fib6_walker *w);
  65
  66 /*
  67  *      A routing update causes an increase of the serial number on the
  68  *      affected subtree. This allows for cached routes to be asynchronously
  69  *      tested when modifications are made to the destination cache as a
  70  *      result of redirects, path MTU changes, etc.
  71  */
  72
  73 static void fib6_gc_timer_cb(struct timer_list *t);
  74
  75 #define FOR_WALKERS(net, w) \
  76         list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)
  77
  78 static void fib6_walker_link(struct net *net, struct fib6_walker *w)
  79 {
  80         write_lock_bh(&net->ipv6.fib6_walker_lock);
  81         list_add(&w->lh, &net->ipv6.fib6_walkers);
  82         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  83 }
  84
  85 static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
  86 {
  87         write_lock_bh(&net->ipv6.fib6_walker_lock);
  88         list_del(&w->lh);
  89         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  90 }
  91
  92 static int fib6_new_sernum(struct net *net)
  93 {
  94         int new, old;
  95
  96         do {
  97                 old = atomic_read(&net->ipv6.fib6_sernum);
  98                 new = old < INT_MAX ? old + 1 : 1;
  99         } while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
 100                                 old, new) != old);
 101         return new;
 102 }
 103
 104 enum {
 105         FIB6_NO_SERNUM_CHANGE = 0,
 106 };
 107
 108 void fib6_update_sernum(struct net *net, struct fib6_info *f6i)
 109 {
 110         struct fib6_node *fn;
 111
 112         fn = rcu_dereference_protected(f6i->fib6_node,
 113                         lockdep_is_held(&f6i->fib6_table->tb6_lock));
 114         if (fn)
 115                 WRITE_ONCE(fn->fn_sernum, fib6_new_sernum(net));
 116 }
 117
 118 /*
 119  *      Auxiliary address test functions for the radix tree.
 120  *
 121  *      These assume a 32bit processor (although it will work on
 122  *      64bit processors)
 123  */
 124
 125 /*
 126  *      test bit
 127  */
 128 #if defined(__LITTLE_ENDIAN)
 129 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
 130 #else
 131 # define BITOP_BE32_SWIZZLE     0
 132 #endif
 133
 134 static __be32 addr_bit_set(const void *token, int fn_bit)
 135 {
 136         const __be32 *addr = token;
 137         /*
 138          * Here,
 139          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
 140          * is optimized version of
 141          *      htonl(1 << ((~fn_bit)&0x1F))
 142          * See include/asm-generic/bitops/le.h.
 143          */
 144         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
 145                addr[fn_bit >> 5];
 146 }
 147
 148 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh)
 149 {
 150         struct fib6_info *f6i;
 151         size_t sz = sizeof(*f6i);
 152
 153         if (with_fib6_nh)
 154                 sz += sizeof(struct fib6_nh);
 155
 156         f6i = kzalloc(sz, gfp_flags);
 157         if (!f6i)
 158                 return NULL;
 159
 160         /* fib6_siblings is a union with nh_list, so this initializes both */
 161         INIT_LIST_HEAD(&f6i->fib6_siblings);
 162         refcount_set(&f6i->fib6_ref, 1);
 163
 164         return f6i;
 165 }
 166
 167 void fib6_info_destroy_rcu(struct rcu_head *head)
 168 {
 169         struct fib6_info *f6i = container_of(head, struct fib6_info, rcu);
 170
 171         WARN_ON(f6i->fib6_node);
 172
 173         if (f6i->nh)
 174                 nexthop_put(f6i->nh);
 175         else
 176                 fib6_nh_release(f6i->fib6_nh);
 177
 178         ip_fib_metrics_put(f6i->fib6_metrics);
 179         kfree(f6i);
 180 }
 181 EXPORT_SYMBOL_GPL(fib6_info_destroy_rcu);
 182
 183 static struct fib6_node *node_alloc(struct net *net)
 184 {
 185         struct fib6_node *fn;
 186
 187         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 188         if (fn)
 189                 net->ipv6.rt6_stats->fib_nodes++;
 190
 191         return fn;
 192 }
 193
 194 static void node_free_immediate(struct net *net, struct fib6_node *fn)
 195 {
 196         kmem_cache_free(fib6_node_kmem, fn);
 197         net->ipv6.rt6_stats->fib_nodes--;
 198 }
 199
 200 static void node_free_rcu(struct rcu_head *head)
 201 {
 202         struct fib6_node *fn = container_of(head, struct fib6_node, rcu);
 203
 204         kmem_cache_free(fib6_node_kmem, fn);
 205 }
 206
 207 static void node_free(struct net *net, struct fib6_node *fn)
 208 {
 209         call_rcu(&fn->rcu, node_free_rcu);
 210         net->ipv6.rt6_stats->fib_nodes--;
 211 }
 212
 213 static void fib6_free_table(struct fib6_table *table)
 214 {
 215         inetpeer_invalidate_tree(&table->tb6_peers);
 216         kfree(table);
 217 }
 218
 219 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 220 {
 221         unsigned int h;
 222
 223         /*
 224          * Initialize table lock at a single place to give lockdep a key,
 225          * tables aren't visible prior to being linked to the list.
 226          */
 227         spin_lock_init(&tb->tb6_lock);
 228         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 229
 230         /*
 231          * No protection necessary, this is the only list mutatation
 232          * operation, tables never disappear once they exist.
 233          */
 234         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 235 }
 236
 237 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 238
 239 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 240 {
 241         struct fib6_table *table;
 242
 243         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 244         if (table) {
 245                 table->tb6_id = id;
 246                 rcu_assign_pointer(table->tb6_root.leaf,
 247                                    net->ipv6.fib6_null_entry);
 248                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 249                 inet_peer_base_init(&table->tb6_peers);
 250         }
 251
 252         return table;
 253 }
 254
 255 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 256 {
 257         struct fib6_table *tb;
 258
 259         if (id == 0)
 260                 id = RT6_TABLE_MAIN;
 261         tb = fib6_get_table(net, id);
 262         if (tb)
 263                 return tb;
 264
 265         tb = fib6_alloc_table(net, id);
 266         if (tb)
 267                 fib6_link_table(net, tb);
 268
 269         return tb;
 270 }
 271 EXPORT_SYMBOL_GPL(fib6_new_table);
 272
 273 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 274 {
 275         struct fib6_table *tb;
 276         struct hlist_head *head;
 277         unsigned int h;
 278
 279         if (id == 0)
 280                 id = RT6_TABLE_MAIN;
 281         h = id & (FIB6_TABLE_HASHSZ - 1);
 282         rcu_read_lock();
 283         head = &net->ipv6.fib_table_hash[h];
 284         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 285                 if (tb->tb6_id == id) {
 286                         rcu_read_unlock();
 287                         return tb;
 288                 }
 289         }
 290         rcu_read_unlock();
 291
 292         return NULL;
 293 }
 294 EXPORT_SYMBOL_GPL(fib6_get_table);
 295
 296 static void __net_init fib6_tables_init(struct net *net)
 297 {
 298         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 299         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 300 }
 301 #else
 302
 303 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 304 {
 305         return fib6_get_table(net, id);
 306 }
 307
 308 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 309 {
 310           return net->ipv6.fib6_main_tbl;
 311 }
 312
 313 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 314                                    const struct sk_buff *skb,
 315                                    int flags, pol_lookup_t lookup)
 316 {
 317         struct rt6_info *rt;
 318
 319         rt = pol_lookup_func(lookup,
 320                         net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
 321         if (rt->dst.error == -EAGAIN) {
 322                 ip6_rt_put_flags(rt, flags);
 323                 rt = net->ipv6.ip6_null_entry;
 324                 if (!(flags & RT6_LOOKUP_F_DST_NOREF))
 325                         dst_hold(&rt->dst);
 326         }
 327
 328         return &rt->dst;
 329 }
 330
 331 /* called with rcu lock held; no reference taken on fib6_info */
 332 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 333                 struct fib6_result *res, int flags)
 334 {
 335         return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6,
 336                                  res, flags);
 337 }
 338
 339 static void __net_init fib6_tables_init(struct net *net)
 340 {
 341         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 342 }
 343
 344 #endif
 345
 346 unsigned int fib6_tables_seq_read(struct net *net)
 347 {
 348         unsigned int h, fib_seq = 0;
 349
 350         rcu_read_lock();
 351         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
 352                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
 353                 struct fib6_table *tb;
 354
 355                 hlist_for_each_entry_rcu(tb, head, tb6_hlist)
 356                         fib_seq += tb->fib_seq;
 357         }
 358         rcu_read_unlock();
 359
 360         return fib_seq;
 361 }
 362
 363 static int call_fib6_entry_notifier(struct notifier_block *nb,
 364                                     enum fib_event_type event_type,
 365                                     struct fib6_info *rt,
 366                                     struct netlink_ext_ack *extack)
 367 {
 368         struct fib6_entry_notifier_info info = {
 369                 .info.extack = extack,
 370                 .rt = rt,
 371         };
 372
 373         return call_fib6_notifier(nb, event_type, &info.info);
 374 }
 375
 376 static int call_fib6_multipath_entry_notifier(struct notifier_block *nb,
 377                                               enum fib_event_type event_type,
 378                                               struct fib6_info *rt,
 379                                               unsigned int nsiblings,
 380                                               struct netlink_ext_ack *extack)
 381 {
 382         struct fib6_entry_notifier_info info = {
 383                 .info.extack = extack,
 384                 .rt = rt,
 385                 .nsiblings = nsiblings,
 386         };
 387
 388         return call_fib6_notifier(nb, event_type, &info.info);
 389 }
 390
 391 int call_fib6_entry_notifiers(struct net *net,
 392                               enum fib_event_type event_type,
 393                               struct fib6_info *rt,
 394                               struct netlink_ext_ack *extack)
 395 {
 396         struct fib6_entry_notifier_info info = {
 397                 .info.extack = extack,
 398                 .rt = rt,
 399         };
 400
 401         rt->fib6_table->fib_seq++;
 402         return call_fib6_notifiers(net, event_type, &info.info);
 403 }
 404
 405 int call_fib6_multipath_entry_notifiers(struct net *net,
 406                                         enum fib_event_type event_type,
 407                                         struct fib6_info *rt,
 408                                         unsigned int nsiblings,
 409                                         struct netlink_ext_ack *extack)
 410 {
 411         struct fib6_entry_notifier_info info = {
 412                 .info.extack = extack,
 413                 .rt = rt,
 414                 .nsiblings = nsiblings,
 415         };
 416
 417         rt->fib6_table->fib_seq++;
 418         return call_fib6_notifiers(net, event_type, &info.info);
 419 }
 420
 421 int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt)
 422 {
 423         struct fib6_entry_notifier_info info = {
 424                 .rt = rt,
 425                 .nsiblings = rt->fib6_nsiblings,
 426         };
 427
 428         rt->fib6_table->fib_seq++;
 429         return call_fib6_notifiers(net, FIB_EVENT_ENTRY_REPLACE, &info.info);
 430 }
 431
 432 struct fib6_dump_arg {
 433         struct net *net;
 434         struct notifier_block *nb;
 435         struct netlink_ext_ack *extack;
 436 };
 437
 438 static int fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
 439 {
 440         enum fib_event_type fib_event = FIB_EVENT_ENTRY_REPLACE;
 441         int err;
 442
 443         if (!rt || rt == arg->net->ipv6.fib6_null_entry)
 444                 return 0;
 445
 446         if (rt->fib6_nsiblings)
 447                 err = call_fib6_multipath_entry_notifier(arg->nb, fib_event,
 448                                                          rt,
 449                                                          rt->fib6_nsiblings,
 450                                                          arg->extack);
 451         else
 452                 err = call_fib6_entry_notifier(arg->nb, fib_event, rt,
 453                                                arg->extack);
 454
 455         return err;
 456 }
 457
 458 static int fib6_node_dump(struct fib6_walker *w)
 459 {
 460         int err;
 461
 462         err = fib6_rt_dump(w->leaf, w->args);
 463         w->leaf = NULL;
 464         return err;
 465 }
 466
 467 static int fib6_table_dump(struct net *net, struct fib6_table *tb,
 468                            struct fib6_walker *w)
 469 {
 470         int err;
 471
 472         w->root = &tb->tb6_root;
 473         spin_lock_bh(&tb->tb6_lock);
 474         err = fib6_walk(net, w);
 475         spin_unlock_bh(&tb->tb6_lock);
 476         return err;
 477 }
 478
 479 /* Called with rcu_read_lock() */
 480 int fib6_tables_dump(struct net *net, struct notifier_block *nb,
 481                      struct netlink_ext_ack *extack)
 482 {
 483         struct fib6_dump_arg arg;
 484         struct fib6_walker *w;
 485         unsigned int h;
 486         int err = 0;
 487
 488         w = kzalloc(sizeof(*w), GFP_ATOMIC);
 489         if (!w)
 490                 return -ENOMEM;
 491
 492         w->func = fib6_node_dump;
 493         arg.net = net;
 494         arg.nb = nb;
 495         arg.extack = extack;
 496         w->args = &arg;
 497
 498         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
 499                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
 500                 struct fib6_table *tb;
 501
 502                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 503                         err = fib6_table_dump(net, tb, w);
 504                         if (err)
 505                                 goto out;
 506                 }
 507         }
 508
 509 out:
 510         kfree(w);
 511
 512         /* The tree traversal function should never return a positive value. */
 513         return err > 0 ? -EINVAL : err;
 514 }
 515
 516 static int fib6_dump_node(struct fib6_walker *w)
 517 {
 518         int res;
 519         struct fib6_info *rt;
 520
 521         for_each_fib6_walker_rt(w) {
 522                 res = rt6_dump_route(rt, w->args, w->skip_in_node);
 523                 if (res >= 0) {
 524                         /* Frame is full, suspend walking */
 525                         w->leaf = rt;
 526
 527                         /* We'll restart from this node, so if some routes were
 528                          * already dumped, skip them next time.
 529                          */
 530                         w->skip_in_node += res;
 531
 532                         return 1;
 533                 }
 534                 w->skip_in_node = 0;
 535
 536                 /* Multipath routes are dumped in one route with the
 537                  * RTA_MULTIPATH attribute. Jump 'rt' to point to the
 538                  * last sibling of this route (no need to dump the
 539                  * sibling routes again)
 540                  */
 541                 if (rt->fib6_nsiblings)
 542                         rt = list_last_entry(&rt->fib6_siblings,
 543                                              struct fib6_info,
 544                                              fib6_siblings);
 545         }
 546         w->leaf = NULL;
 547         return 0;
 548 }
 549
 550 static void fib6_dump_end(struct netlink_callback *cb)
 551 {
 552         struct net *net = sock_net(cb->skb->sk);
 553         struct fib6_walker *w = (void *)cb->args[2];
 554
 555         if (w) {
 556                 if (cb->args[4]) {
 557                         cb->args[4] = 0;
 558                         fib6_walker_unlink(net, w);
 559                 }
 560                 cb->args[2] = 0;
 561                 kfree(w);
 562         }
 563         cb->done = (void *)cb->args[3];
 564         cb->args[1] = 3;
 565 }
 566
 567 static int fib6_dump_done(struct netlink_callback *cb)
 568 {
 569         fib6_dump_end(cb);
 570         return cb->done ? cb->done(cb) : 0;
 571 }
 572
 573 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 574                            struct netlink_callback *cb)
 575 {
 576         struct net *net = sock_net(skb->sk);
 577         struct fib6_walker *w;
 578         int res;
 579
 580         w = (void *)cb->args[2];
 581         w->root = &table->tb6_root;
 582
 583         if (cb->args[4] == 0) {
 584                 w->count = 0;
 585                 w->skip = 0;
 586                 w->skip_in_node = 0;
 587
 588                 spin_lock_bh(&table->tb6_lock);
 589                 res = fib6_walk(net, w);
 590                 spin_unlock_bh(&table->tb6_lock);
 591                 if (res > 0) {
 592                         cb->args[4] = 1;
 593                         cb->args[5] = READ_ONCE(w->root->fn_sernum);
 594                 }
 595         } else {
 596                 int sernum = READ_ONCE(w->root->fn_sernum);
 597                 if (cb->args[5] != sernum) {
 598                         /* Begin at the root if the tree changed */
 599                         cb->args[5] = sernum;
 600                         w->state = FWS_INIT;
 601                         w->node = w->root;
 602                         w->skip = w->count;
 603                         w->skip_in_node = 0;
 604                 } else
 605                         w->skip = 0;
 606
 607                 spin_lock_bh(&table->tb6_lock);
 608                 res = fib6_walk_continue(w);
 609                 spin_unlock_bh(&table->tb6_lock);
 610                 if (res <= 0) {
 611                         fib6_walker_unlink(net, w);
 612                         cb->args[4] = 0;
 613                 }
 614         }
 615
 616         return res;
 617 }
 618
 619 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 620 {
 621         struct rt6_rtnl_dump_arg arg = { .filter.dump_exceptions = true,
 622                                          .filter.dump_routes = true };
 623         const struct nlmsghdr *nlh = cb->nlh;
 624         struct net *net = sock_net(skb->sk);
 625         unsigned int h, s_h;
 626         unsigned int e = 0, s_e;
 627         struct fib6_walker *w;
 628         struct fib6_table *tb;
 629         struct hlist_head *head;
 630         int res = 0;
 631
 632         if (cb->strict_check) {
 633                 int err;
 634
 635                 err = ip_valid_fib_dump_req(net, nlh, &arg.filter, cb);
 636                 if (err < 0)
 637                         return err;
 638         } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
 639                 struct rtmsg *rtm = nlmsg_data(nlh);
 640
 641                 if (rtm->rtm_flags & RTM_F_PREFIX)
 642                         arg.filter.flags = RTM_F_PREFIX;
 643         }
 644
 645         w = (void *)cb->args[2];
 646         if (!w) {
 647                 /* New dump:
 648                  *
 649                  * 1. hook callback destructor.
 650                  */
 651                 cb->args[3] = (long)cb->done;
 652                 cb->done = fib6_dump_done;
 653
 654                 /*
 655                  * 2. allocate and initialize walker.
 656                  */
 657                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 658                 if (!w)
 659                         return -ENOMEM;
 660                 w->func = fib6_dump_node;
 661                 cb->args[2] = (long)w;
 662         }
 663
 664         arg.skb = skb;
 665         arg.cb = cb;
 666         arg.net = net;
 667         w->args = &arg;
 668
 669         if (arg.filter.table_id) {
 670                 tb = fib6_get_table(net, arg.filter.table_id);
 671                 if (!tb) {
 672                         if (rtnl_msg_family(cb->nlh) != PF_INET6)
 673                                 goto out;
 674
 675                         NL_SET_ERR_MSG_MOD(cb->extack, "FIB table does not exist");
 676                         return -ENOENT;
 677                 }
 678
 679                 if (!cb->args[0]) {
 680                         res = fib6_dump_table(tb, skb, cb);
 681                         if (!res)
 682                                 cb->args[0] = 1;
 683                 }
 684                 goto out;
 685         }
 686
 687         s_h = cb->args[0];
 688         s_e = cb->args[1];
 689
 690         rcu_read_lock();
 691         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 692                 e = 0;
 693                 head = &net->ipv6.fib_table_hash[h];
 694                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 695                         if (e < s_e)
 696                                 goto next;
 697                         res = fib6_dump_table(tb, skb, cb);
 698                         if (res != 0)
 699                                 goto out_unlock;
 700 next:
 701                         e++;
 702                 }
 703         }
 704 out_unlock:
 705         rcu_read_unlock();
 706         cb->args[1] = e;
 707         cb->args[0] = h;
 708 out:
 709         res = res < 0 ? res : skb->len;
 710         if (res <= 0)
 711                 fib6_dump_end(cb);
 712         return res;
 713 }
 714
 715 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val)
 716 {
 717         if (!f6i)
 718                 return;
 719
 720         if (f6i->fib6_metrics == &dst_default_metrics) {
 721                 struct dst_metrics *p = kzalloc(sizeof(*p), GFP_ATOMIC);
 722
 723                 if (!p)
 724                         return;
 725
 726                 refcount_set(&p->refcnt, 1);
 727                 f6i->fib6_metrics = p;
 728         }
 729
 730         f6i->fib6_metrics->metrics[metric - 1] = val;
 731 }
 732
 733 /*
 734  *      Routing Table
 735  *
 736  *      return the appropriate node for a routing tree "add" operation
 737  *      by either creating and inserting or by returning an existing
 738  *      node.
 739  */
 740
 741 static struct fib6_node *fib6_add_1(struct net *net,
 742                                     struct fib6_table *table,
 743                                     struct fib6_node *root,
 744                                     struct in6_addr *addr, int plen,
 745                                     int offset, int allow_create,
 746                                     int replace_required,
 747                                     struct netlink_ext_ack *extack)
 748 {
 749         struct fib6_node *fn, *in, *ln;
 750         struct fib6_node *pn = NULL;
 751         struct rt6key *key;
 752         int     bit;
 753         __be32  dir = 0;
 754
 755         RT6_TRACE("fib6_add_1\n");
 756
 757         /* insert node in tree */
 758
 759         fn = root;
 760
 761         do {
 762                 struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
 763                                             lockdep_is_held(&table->tb6_lock));
 764                 key = (struct rt6key *)((u8 *)leaf + offset);
 765
 766                 /*
 767                  *      Prefix match
 768                  */
 769                 if (plen < fn->fn_bit ||
 770                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 771                         if (!allow_create) {
 772                                 if (replace_required) {
 773                                         NL_SET_ERR_MSG(extack,
 774                                                        "Can not replace route - no match found");
 775                                         pr_warn("Can't replace route, no match found\n");
 776                                         return ERR_PTR(-ENOENT);
 777                                 }
 778                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 779                         }
 780                         goto insert_above;
 781                 }
 782
 783                 /*
 784                  *      Exact match ?
 785                  */
 786
 787                 if (plen == fn->fn_bit) {
 788                         /* clean up an intermediate node */
 789                         if (!(fn->fn_flags & RTN_RTINFO)) {
 790                                 RCU_INIT_POINTER(fn->leaf, NULL);
 791                                 fib6_info_release(leaf);
 792                         /* remove null_entry in the root node */
 793                         } else if (fn->fn_flags & RTN_TL_ROOT &&
 794                                    rcu_access_pointer(fn->leaf) ==
 795                                    net->ipv6.fib6_null_entry) {
 796                                 RCU_INIT_POINTER(fn->leaf, NULL);
 797                         }
 798
 799                         return fn;
 800                 }
 801
 802                 /*
 803                  *      We have more bits to go
 804                  */
 805
 806                 /* Try to walk down on tree. */
 807                 dir = addr_bit_set(addr, fn->fn_bit);
 808                 pn = fn;
 809                 fn = dir ?
 810                      rcu_dereference_protected(fn->right,
 811                                         lockdep_is_held(&table->tb6_lock)) :
 812                      rcu_dereference_protected(fn->left,
 813                                         lockdep_is_held(&table->tb6_lock));
 814         } while (fn);
 815
 816         if (!allow_create) {
 817                 /* We should not create new node because
 818                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 819                  * I assume it is safe to require NLM_F_CREATE when
 820                  * REPLACE flag is used! Later we may want to remove the
 821                  * check for replace_required, because according
 822                  * to netlink specification, NLM_F_CREATE
 823                  * MUST be specified if new route is created.
 824                  * That would keep IPv6 consistent with IPv4
 825                  */
 826                 if (replace_required) {
 827                         NL_SET_ERR_MSG(extack,
 828                                        "Can not replace route - no match found");
 829                         pr_warn("Can't replace route, no match found\n");
 830                         return ERR_PTR(-ENOENT);
 831                 }
 832                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 833         }
 834         /*
 835          *      We walked to the bottom of tree.
 836          *      Create new leaf node without children.
 837          */
 838
 839         ln = node_alloc(net);
 840
 841         if (!ln)
 842                 return ERR_PTR(-ENOMEM);
 843         ln->fn_bit = plen;
 844         RCU_INIT_POINTER(ln->parent, pn);
 845
 846         if (dir)
 847                 rcu_assign_pointer(pn->right, ln);
 848         else
 849                 rcu_assign_pointer(pn->left, ln);
 850
 851         return ln;
 852
 853
 854 insert_above:
 855         /*
 856          * split since we don't have a common prefix anymore or
 857          * we have a less significant route.
 858          * we've to insert an intermediate node on the list
 859          * this new node will point to the one we need to create
 860          * and the current
 861          */
 862
 863         pn = rcu_dereference_protected(fn->parent,
 864                                        lockdep_is_held(&table->tb6_lock));
 865
 866         /* find 1st bit in difference between the 2 addrs.
 867
 868            See comment in __ipv6_addr_diff: bit may be an invalid value,
 869            but if it is >= plen, the value is ignored in any case.
 870          */
 871
 872         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 873
 874         /*
 875          *              (intermediate)[in]
 876          *                /        \
 877          *      (new leaf node)[ln] (old node)[fn]
 878          */
 879         if (plen > bit) {
 880                 in = node_alloc(net);
 881                 ln = node_alloc(net);
 882
 883                 if (!in || !ln) {
 884                         if (in)
 885                                 node_free_immediate(net, in);
 886                         if (ln)
 887                                 node_free_immediate(net, ln);
 888                         return ERR_PTR(-ENOMEM);
 889                 }
 890
 891                 /*
 892                  * new intermediate node.
 893                  * RTN_RTINFO will
 894                  * be off since that an address that chooses one of
 895                  * the branches would not match less specific routes
 896                  * in the other branch
 897                  */
 898
 899                 in->fn_bit = bit;
 900
 901                 RCU_INIT_POINTER(in->parent, pn);
 902                 in->leaf = fn->leaf;
 903                 fib6_info_hold(rcu_dereference_protected(in->leaf,
 904                                 lockdep_is_held(&table->tb6_lock)));
 905
 906                 /* update parent pointer */
 907                 if (dir)
 908                         rcu_assign_pointer(pn->right, in);
 909                 else
 910                         rcu_assign_pointer(pn->left, in);
 911
 912                 ln->fn_bit = plen;
 913
 914                 RCU_INIT_POINTER(ln->parent, in);
 915                 rcu_assign_pointer(fn->parent, in);
 916
 917                 if (addr_bit_set(addr, bit)) {
 918                         rcu_assign_pointer(in->right, ln);
 919                         rcu_assign_pointer(in->left, fn);
 920                 } else {
 921                         rcu_assign_pointer(in->left, ln);
 922                         rcu_assign_pointer(in->right, fn);
 923                 }
 924         } else { /* plen <= bit */
 925
 926                 /*
 927                  *              (new leaf node)[ln]
 928                  *                /        \
 929                  *           (old node)[fn] NULL
 930                  */
 931
 932                 ln = node_alloc(net);
 933
 934                 if (!ln)
 935                         return ERR_PTR(-ENOMEM);
 936
 937                 ln->fn_bit = plen;
 938
 939                 RCU_INIT_POINTER(ln->parent, pn);
 940
 941                 if (addr_bit_set(&key->addr, plen))
 942                         RCU_INIT_POINTER(ln->right, fn);
 943                 else
 944                         RCU_INIT_POINTER(ln->left, fn);
 945
 946                 rcu_assign_pointer(fn->parent, ln);
 947
 948                 if (dir)
 949                         rcu_assign_pointer(pn->right, ln);
 950                 else
 951                         rcu_assign_pointer(pn->left, ln);
 952         }
 953         return ln;
 954 }
 955
 956 static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh,
 957                                   const struct fib6_info *match,
 958                                   const struct fib6_table *table)
 959 {
 960         int cpu;
 961
 962         if (!fib6_nh->rt6i_pcpu)
 963                 return;
 964
 965         /* release the reference to this fib entry from
 966          * all of its cached pcpu routes
 967          */
 968         for_each_possible_cpu(cpu) {
 969                 struct rt6_info **ppcpu_rt;
 970                 struct rt6_info *pcpu_rt;
 971
 972                 ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
 973                 pcpu_rt = *ppcpu_rt;
 974
 975                 /* only dropping the 'from' reference if the cached route
 976                  * is using 'match'. The cached pcpu_rt->from only changes
 977                  * from a fib6_info to NULL (ip6_dst_destroy); it can never
 978                  * change from one fib6_info reference to another
 979                  */
 980                 if (pcpu_rt && rcu_access_pointer(pcpu_rt->from) == match) {
 981                         struct fib6_info *from;
 982
 983                         from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
 984                         fib6_info_release(from);
 985                 }
 986         }
 987 }
 988
 989 struct fib6_nh_pcpu_arg {
 990         struct fib6_info        *from;
 991         const struct fib6_table *table;
 992 };
 993
 994 static int fib6_nh_drop_pcpu_from(struct fib6_nh *nh, void *_arg)
 995 {
 996         struct fib6_nh_pcpu_arg *arg = _arg;
 997
 998         __fib6_drop_pcpu_from(nh, arg->from, arg->table);
 999         return 0;
1000 }
1001
1002 static void fib6_drop_pcpu_from(struct fib6_info *f6i,
1003                                 const struct fib6_table *table)
1004 {
1005         /* Make sure rt6_make_pcpu_route() wont add other percpu routes
1006          * while we are cleaning them here.
1007          */
1008         f6i->fib6_destroying = 1;
1009         mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
1010
1011         if (f6i->nh) {
1012                 struct fib6_nh_pcpu_arg arg = {
1013                         .from = f6i,
1014                         .table = table
1015                 };
1016
1017                 nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_drop_pcpu_from,
1018                                          &arg);
1019         } else {
1020                 struct fib6_nh *fib6_nh;
1021
1022                 fib6_nh = f6i->fib6_nh;
1023                 __fib6_drop_pcpu_from(fib6_nh, f6i, table);
1024         }
1025 }
1026
1027 static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn,
1028                           struct net *net)
1029 {
1030         struct fib6_table *table = rt->fib6_table;
1031
1032         /* Flush all cached dst in exception table */
1033         rt6_flush_exceptions(rt);
1034         fib6_drop_pcpu_from(rt, table);
1035
1036         if (rt->nh && !list_empty(&rt->nh_list))
1037                 list_del_init(&rt->nh_list);
1038
1039         if (refcount_read(&rt->fib6_ref) != 1) {
1040                 /* This route is used as dummy address holder in some split
1041                  * nodes. It is not leaked, but it still holds other resources,
1042                  * which must be released in time. So, scan ascendant nodes
1043                  * and replace dummy references to this route with references
1044                  * to still alive ones.
1045                  */
1046                 while (fn) {
1047                         struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
1048                                             lockdep_is_held(&table->tb6_lock));
1049                         struct fib6_info *new_leaf;
1050                         if (!(fn->fn_flags & RTN_RTINFO) && leaf == rt) {
1051                                 new_leaf = fib6_find_prefix(net, table, fn);
1052                                 fib6_info_hold(new_leaf);
1053
1054                                 rcu_assign_pointer(fn->leaf, new_leaf);
1055                                 fib6_info_release(rt);
1056                         }
1057                         fn = rcu_dereference_protected(fn->parent,
1058                                     lockdep_is_held(&table->tb6_lock));
1059                 }
1060         }
1061 }
1062
1063 /*
1064  *      Insert routing information in a node.
1065  */
1066
1067 static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
1068                             struct nl_info *info,
1069                             struct netlink_ext_ack *extack)
1070 {
1071         struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
1072                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1073         struct fib6_info *iter = NULL;
1074         struct fib6_info __rcu **ins;
1075         struct fib6_info __rcu **fallback_ins = NULL;
1076         int replace = (info->nlh &&
1077                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
1078         int add = (!info->nlh ||
1079                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
1080         int found = 0;
1081         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
1082         bool notify_sibling_rt = false;
1083         u16 nlflags = NLM_F_EXCL;
1084         int err;
1085
1086         if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))
1087                 nlflags |= NLM_F_APPEND;
1088
1089         ins = &fn->leaf;
1090
1091         for (iter = leaf; iter;
1092              iter = rcu_dereference_protected(iter->fib6_next,
1093                                 lockdep_is_held(&rt->fib6_table->tb6_lock))) {
1094                 /*
1095                  *      Search for duplicates
1096                  */
1097
1098                 if (iter->fib6_metric == rt->fib6_metric) {
1099                         /*
1100                          *      Same priority level
1101                          */
1102                         if (info->nlh &&
1103                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
1104                                 return -EEXIST;
1105
1106                         nlflags &= ~NLM_F_EXCL;
1107                         if (replace) {
1108                                 if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
1109                                         found++;
1110                                         break;
1111                                 }
1112                                 fallback_ins = fallback_ins ?: ins;
1113                                 goto next_iter;
1114                         }
1115
1116                         if (rt6_duplicate_nexthop(iter, rt)) {
1117                                 if (rt->fib6_nsiblings)
1118                                         rt->fib6_nsiblings = 0;
1119                                 if (!(iter->fib6_flags & RTF_EXPIRES))
1120                                         return -EEXIST;
1121                                 if (!(rt->fib6_flags & RTF_EXPIRES))
1122                                         fib6_clean_expires(iter);
1123                                 else
1124                                         fib6_set_expires(iter, rt->expires);
1125
1126                                 if (rt->fib6_pmtu)
1127                                         fib6_metric_set(iter, RTAX_MTU,
1128                                                         rt->fib6_pmtu);
1129                                 return -EEXIST;
1130                         }
1131                         /* If we have the same destination and the same metric,
1132                          * but not the same gateway, then the route we try to
1133                          * add is sibling to this route, increment our counter
1134                          * of siblings, and later we will add our route to the
1135                          * list.
1136                          * Only static routes (which don't have flag
1137                          * RTF_EXPIRES) are used for ECMPv6.
1138                          *
1139                          * To avoid long list, we only had siblings if the
1140                          * route have a gateway.
1141                          */
1142                         if (rt_can_ecmp &&
1143                             rt6_qualify_for_ecmp(iter))
1144                                 rt->fib6_nsiblings++;
1145                 }
1146
1147                 if (iter->fib6_metric > rt->fib6_metric)
1148                         break;
1149
1150 next_iter:
1151                 ins = &iter->fib6_next;
1152         }
1153
1154         if (fallback_ins && !found) {
1155                 /* No matching route with same ecmp-able-ness found, replace
1156                  * first matching route
1157                  */
1158                 ins = fallback_ins;
1159                 iter = rcu_dereference_protected(*ins,
1160                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1161                 found++;
1162         }
1163
1164         /* Reset round-robin state, if necessary */
1165         if (ins == &fn->leaf)
1166                 fn->rr_ptr = NULL;
1167
1168         /* Link this route to others same route. */
1169         if (rt->fib6_nsiblings) {
1170                 unsigned int fib6_nsiblings;
1171                 struct fib6_info *sibling, *temp_sibling;
1172
1173                 /* Find the first route that have the same metric */
1174                 sibling = leaf;
1175                 notify_sibling_rt = true;
1176                 while (sibling) {
1177                         if (sibling->fib6_metric == rt->fib6_metric &&
1178                             rt6_qualify_for_ecmp(sibling)) {
1179                                 list_add_tail(&rt->fib6_siblings,
1180                                               &sibling->fib6_siblings);
1181                                 break;
1182                         }
1183                         sibling = rcu_dereference_protected(sibling->fib6_next,
1184                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1185                         notify_sibling_rt = false;
1186                 }
1187                 /* For each sibling in the list, increment the counter of
1188                  * siblings. BUG() if counters does not match, list of siblings
1189                  * is broken!
1190                  */
1191                 fib6_nsiblings = 0;
1192                 list_for_each_entry_safe(sibling, temp_sibling,
1193                                          &rt->fib6_siblings, fib6_siblings) {
1194                         sibling->fib6_nsiblings++;
1195                         BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings);
1196                         fib6_nsiblings++;
1197                 }
1198                 BUG_ON(fib6_nsiblings != rt->fib6_nsiblings);
1199                 rt6_multipath_rebalance(temp_sibling);
1200         }
1201
1202         /*
1203          *      insert node
1204          */
1205         if (!replace) {
1206                 if (!add)
1207                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
1208
1209 add:
1210                 nlflags |= NLM_F_CREATE;
1211
1212                 /* The route should only be notified if it is the first
1213                  * route in the node or if it is added as a sibling
1214                  * route to the first route in the node.
1215                  */
1216                 if (!info->skip_notify_kernel &&
1217                     (notify_sibling_rt || ins == &fn->leaf)) {
1218                         enum fib_event_type fib_event;
1219
1220                         if (notify_sibling_rt)
1221                                 fib_event = FIB_EVENT_ENTRY_APPEND;
1222                         else
1223                                 fib_event = FIB_EVENT_ENTRY_REPLACE;
1224                         err = call_fib6_entry_notifiers(info->nl_net,
1225                                                         fib_event, rt,
1226                                                         extack);
1227                         if (err) {
1228                                 struct fib6_info *sibling, *next_sibling;
1229
1230                                 /* If the route has siblings, then it first
1231                                  * needs to be unlinked from them.
1232                                  */
1233                                 if (!rt->fib6_nsiblings)
1234                                         return err;
1235
1236                                 list_for_each_entry_safe(sibling, next_sibling,
1237                                                          &rt->fib6_siblings,
1238                                                          fib6_siblings)
1239                                         sibling->fib6_nsiblings--;
1240                                 rt->fib6_nsiblings = 0;
1241                                 list_del_init(&rt->fib6_siblings);
1242                                 rt6_multipath_rebalance(next_sibling);
1243                                 return err;
1244                         }
1245                 }
1246
1247                 rcu_assign_pointer(rt->fib6_next, iter);
1248                 fib6_info_hold(rt);
1249                 rcu_assign_pointer(rt->fib6_node, fn);
1250                 rcu_assign_pointer(*ins, rt);
1251                 if (!info->skip_notify)
1252                         inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
1253                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
1254
1255                 if (!(fn->fn_flags & RTN_RTINFO)) {
1256                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1257                         fn->fn_flags |= RTN_RTINFO;
1258                 }
1259
1260         } else {
1261                 int nsiblings;
1262
1263                 if (!found) {
1264                         if (add)
1265                                 goto add;
1266                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
1267                         return -ENOENT;
1268                 }
1269
1270                 if (!info->skip_notify_kernel && ins == &fn->leaf) {
1271                         err = call_fib6_entry_notifiers(info->nl_net,
1272                                                         FIB_EVENT_ENTRY_REPLACE,
1273                                                         rt, extack);
1274                         if (err)
1275                                 return err;
1276                 }
1277
1278                 fib6_info_hold(rt);
1279                 rcu_assign_pointer(rt->fib6_node, fn);
1280                 rt->fib6_next = iter->fib6_next;
1281                 rcu_assign_pointer(*ins, rt);
1282                 if (!info->skip_notify)
1283                         inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
1284                 if (!(fn->fn_flags & RTN_RTINFO)) {
1285                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1286                         fn->fn_flags |= RTN_RTINFO;
1287                 }
1288                 nsiblings = iter->fib6_nsiblings;
1289                 iter->fib6_node = NULL;
1290                 fib6_purge_rt(iter, fn, info->nl_net);
1291                 if (rcu_access_pointer(fn->rr_ptr) == iter)
1292                         fn->rr_ptr = NULL;
1293                 fib6_info_release(iter);
1294
1295                 if (nsiblings) {
1296                         /* Replacing an ECMP route, remove all siblings */
1297                         ins = &rt->fib6_next;
1298                         iter = rcu_dereference_protected(*ins,
1299                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1300                         while (iter) {
1301                                 if (iter->fib6_metric > rt->fib6_metric)
1302                                         break;
1303                                 if (rt6_qualify_for_ecmp(iter)) {
1304                                         *ins = iter->fib6_next;
1305                                         iter->fib6_node = NULL;
1306                                         fib6_purge_rt(iter, fn, info->nl_net);
1307                                         if (rcu_access_pointer(fn->rr_ptr) == iter)
1308                                                 fn->rr_ptr = NULL;
1309                                         fib6_info_release(iter);
1310                                         nsiblings--;
1311                                         info->nl_net->ipv6.rt6_stats->fib_rt_entries--;
1312                                 } else {
1313                                         ins = &iter->fib6_next;
1314                                 }
1315                                 iter = rcu_dereference_protected(*ins,
1316                                         lockdep_is_held(&rt->fib6_table->tb6_lock));
1317                         }
1318                         WARN_ON(nsiblings != 0);
1319                 }
1320         }
1321
1322         return 0;
1323 }
1324
1325 static void fib6_start_gc(struct net *net, struct fib6_info *rt)
1326 {
1327         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
1328             (rt->fib6_flags & RTF_EXPIRES))
1329                 mod_timer(&net->ipv6.ip6_fib_timer,
1330                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1331 }
1332
1333 void fib6_force_start_gc(struct net *net)
1334 {
1335         if (!timer_pending(&net->ipv6.ip6_fib_timer))
1336                 mod_timer(&net->ipv6.ip6_fib_timer,
1337                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1338 }
1339
1340 static void __fib6_update_sernum_upto_root(struct fib6_info *rt,
1341                                            int sernum)
1342 {
1343         struct fib6_node *fn = rcu_dereference_protected(rt->fib6_node,
1344                                 lockdep_is_held(&rt->fib6_table->tb6_lock));
1345
1346         /* paired with smp_rmb() in fib6_get_cookie_safe() */
1347         smp_wmb();
1348         while (fn) {
1349                 WRITE_ONCE(fn->fn_sernum, sernum);
1350                 fn = rcu_dereference_protected(fn->parent,
1351                                 lockdep_is_held(&rt->fib6_table->tb6_lock));
1352         }
1353 }
1354
1355 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt)
1356 {
1357         __fib6_update_sernum_upto_root(rt, fib6_new_sernum(net));
1358 }
1359
1360 /* allow ipv4 to update sernum via ipv6_stub */
1361 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i)
1362 {
1363         spin_lock_bh(&f6i->fib6_table->tb6_lock);
1364         fib6_update_sernum_upto_root(net, f6i);
1365         spin_unlock_bh(&f6i->fib6_table->tb6_lock);
1366 }
1367
1368 /*
1369  *      Add routing information to the routing tree.
1370  *      <destination addr>/<source addr>
1371  *      with source addr info in sub-trees
1372  *      Need to own table->tb6_lock
1373  */
1374
1375 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
1376              struct nl_info *info, struct netlink_ext_ack *extack)
1377 {
1378         struct fib6_table *table = rt->fib6_table;
1379         struct fib6_node *fn, *pn = NULL;
1380         int err = -ENOMEM;
1381         int allow_create = 1;
1382         int replace_required = 0;
1383
1384         if (info->nlh) {
1385                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
1386                         allow_create = 0;
1387                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
1388                         replace_required = 1;
1389         }
1390         if (!allow_create && !replace_required)
1391                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
1392
1393         fn = fib6_add_1(info->nl_net, table, root,
1394                         &rt->fib6_dst.addr, rt->fib6_dst.plen,
1395                         offsetof(struct fib6_info, fib6_dst), allow_create,
1396                         replace_required, extack);
1397         if (IS_ERR(fn)) {
1398                 err = PTR_ERR(fn);
1399                 fn = NULL;
1400                 goto out;
1401         }
1402
1403         pn = fn;
1404
1405 #ifdef CONFIG_IPV6_SUBTREES
1406         if (rt->fib6_src.plen) {
1407                 struct fib6_node *sn;
1408
1409                 if (!rcu_access_pointer(fn->subtree)) {
1410                         struct fib6_node *sfn;
1411
1412                         /*
1413                          * Create subtree.
1414                          *
1415                          *              fn[main tree]
1416                          *              |
1417                          *              sfn[subtree root]
1418                          *                 \
1419                          *                  sn[new leaf node]
1420                          */
1421
1422                         /* Create subtree root node */
1423                         sfn = node_alloc(info->nl_net);
1424                         if (!sfn)
1425                                 goto failure;
1426
1427                         fib6_info_hold(info->nl_net->ipv6.fib6_null_entry);
1428                         rcu_assign_pointer(sfn->leaf,
1429                                            info->nl_net->ipv6.fib6_null_entry);
1430                         sfn->fn_flags = RTN_ROOT;
1431
1432                         /* Now add the first leaf node to new subtree */
1433
1434                         sn = fib6_add_1(info->nl_net, table, sfn,
1435                                         &rt->fib6_src.addr, rt->fib6_src.plen,
1436                                         offsetof(struct fib6_info, fib6_src),
1437                                         allow_create, replace_required, extack);
1438
1439                         if (IS_ERR(sn)) {
1440                                 /* If it is failed, discard just allocated
1441                                    root, and then (in failure) stale node
1442                                    in main tree.
1443                                  */
1444                                 node_free_immediate(info->nl_net, sfn);
1445                                 err = PTR_ERR(sn);
1446                                 goto failure;
1447                         }
1448
1449                         /* Now link new subtree to main tree */
1450                         rcu_assign_pointer(sfn->parent, fn);
1451                         rcu_assign_pointer(fn->subtree, sfn);
1452                 } else {
1453                         sn = fib6_add_1(info->nl_net, table, FIB6_SUBTREE(fn),
1454                                         &rt->fib6_src.addr, rt->fib6_src.plen,
1455                                         offsetof(struct fib6_info, fib6_src),
1456                                         allow_create, replace_required, extack);
1457
1458                         if (IS_ERR(sn)) {
1459                                 err = PTR_ERR(sn);
1460                                 goto failure;
1461                         }
1462                 }
1463
1464                 if (!rcu_access_pointer(fn->leaf)) {
1465                         if (fn->fn_flags & RTN_TL_ROOT) {
1466                                 /* put back null_entry for root node */
1467                                 rcu_assign_pointer(fn->leaf,
1468                                             info->nl_net->ipv6.fib6_null_entry);
1469                         } else {
1470                                 fib6_info_hold(rt);
1471                                 rcu_assign_pointer(fn->leaf, rt);
1472                         }
1473                 }
1474                 fn = sn;
1475         }
1476 #endif
1477
1478         err = fib6_add_rt2node(fn, rt, info, extack);
1479         if (!err) {
1480                 if (rt->nh)
1481                         list_add(&rt->nh_list, &rt->nh->f6i_list);
1482                 __fib6_update_sernum_upto_root(rt, fib6_new_sernum(info->nl_net));
1483                 fib6_start_gc(info->nl_net, rt);
1484         }
1485
1486 out:
1487         if (err) {
1488 #ifdef CONFIG_IPV6_SUBTREES
1489                 /*
1490                  * If fib6_add_1 has cleared the old leaf pointer in the
1491                  * super-tree leaf node we have to find a new one for it.
1492                  */
1493                 if (pn != fn) {
1494                         struct fib6_info *pn_leaf =
1495                                 rcu_dereference_protected(pn->leaf,
1496                                     lockdep_is_held(&table->tb6_lock));
1497                         if (pn_leaf == rt) {
1498                                 pn_leaf = NULL;
1499                                 RCU_INIT_POINTER(pn->leaf, NULL);
1500                                 fib6_info_release(rt);
1501                         }
1502                         if (!pn_leaf && !(pn->fn_flags & RTN_RTINFO)) {
1503                                 pn_leaf = fib6_find_prefix(info->nl_net, table,
1504                                                            pn);
1505 #if RT6_DEBUG >= 2
1506                                 if (!pn_leaf) {
1507                                         WARN_ON(!pn_leaf);
1508                                         pn_leaf =
1509                                             info->nl_net->ipv6.fib6_null_entry;
1510                                 }
1511 #endif
1512                                 fib6_info_hold(pn_leaf);
1513                                 rcu_assign_pointer(pn->leaf, pn_leaf);
1514                         }
1515                 }
1516 #endif
1517                 goto failure;
1518         } else if (fib6_requires_src(rt)) {
1519                 fib6_routes_require_src_inc(info->nl_net);
1520         }
1521         return err;
1522
1523 failure:
1524         /* fn->leaf could be NULL and fib6_repair_tree() needs to be called if:
1525          * 1. fn is an intermediate node and we failed to add the new
1526          * route to it in both subtree creation failure and fib6_add_rt2node()
1527          * failure case.
1528          * 2. fn is the root node in the table and we fail to add the first
1529          * default route to it.
1530          */
1531         if (fn &&
1532             (!(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)) ||
1533              (fn->fn_flags & RTN_TL_ROOT &&
1534               !rcu_access_pointer(fn->leaf))))
1535                 fib6_repair_tree(info->nl_net, table, fn);
1536         return err;
1537 }
1538
1539 /*
1540  *      Routing tree lookup
1541  *
1542  */
1543
1544 struct lookup_args {
1545         int                     offset;         /* key offset on fib6_info */
1546         const struct in6_addr   *addr;          /* search key                   */
1547 };
1548
1549 static struct fib6_node *fib6_node_lookup_1(struct fib6_node *root,
1550                                             struct lookup_args *args)
1551 {
1552         struct fib6_node *fn;
1553         __be32 dir;
1554
1555         if (unlikely(args->offset == 0))
1556                 return NULL;
1557
1558         /*
1559          *      Descend on a tree
1560          */
1561
1562         fn = root;
1563
1564         for (;;) {
1565                 struct fib6_node *next;
1566
1567                 dir = addr_bit_set(args->addr, fn->fn_bit);
1568
1569                 next = dir ? rcu_dereference(fn->right) :
1570                              rcu_dereference(fn->left);
1571
1572                 if (next) {
1573                         fn = next;
1574                         continue;
1575                 }
1576                 break;
1577         }
1578
1579         while (fn) {
1580                 struct fib6_node *subtree = FIB6_SUBTREE(fn);
1581
1582                 if (subtree || fn->fn_flags & RTN_RTINFO) {
1583                         struct fib6_info *leaf = rcu_dereference(fn->leaf);
1584                         struct rt6key *key;
1585
1586                         if (!leaf)
1587                                 goto backtrack;
1588
1589                         key = (struct rt6key *) ((u8 *)leaf + args->offset);
1590
1591                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1592 #ifdef CONFIG_IPV6_SUBTREES
1593                                 if (subtree) {
1594                                         struct fib6_node *sfn;
1595                                         sfn = fib6_node_lookup_1(subtree,
1596                                                                  args + 1);
1597                                         if (!sfn)
1598                                                 goto backtrack;
1599                                         fn = sfn;
1600                                 }
1601 #endif
1602                                 if (fn->fn_flags & RTN_RTINFO)
1603                                         return fn;
1604                         }
1605                 }
1606 backtrack:
1607                 if (fn->fn_flags & RTN_ROOT)
1608                         break;
1609
1610                 fn = rcu_dereference(fn->parent);
1611         }
1612
1613         return NULL;
1614 }
1615
1616 /* called with rcu_read_lock() held
1617  */
1618 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
1619                                    const struct in6_addr *daddr,
1620                                    const struct in6_addr *saddr)
1621 {
1622         struct fib6_node *fn;
1623         struct lookup_args args[] = {
1624                 {
1625                         .offset = offsetof(struct fib6_info, fib6_dst),
1626                         .addr = daddr,
1627                 },
1628 #ifdef CONFIG_IPV6_SUBTREES
1629                 {
1630                         .offset = offsetof(struct fib6_info, fib6_src),
1631                         .addr = saddr,
1632                 },
1633 #endif
1634                 {
1635                         .offset = 0,    /* sentinel */
1636                 }
1637         };
1638
1639         fn = fib6_node_lookup_1(root, daddr ? args : args + 1);
1640         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1641                 fn = root;
1642
1643         return fn;
1644 }
1645
1646 /*
1647  *      Get node with specified destination prefix (and source prefix,
1648  *      if subtrees are used)
1649  *      exact_match == true means we try to find fn with exact match of
1650  *      the passed in prefix addr
1651  *      exact_match == false means we try to find fn with longest prefix
1652  *      match of the passed in prefix addr. This is useful for finding fn
1653  *      for cached route as it will be stored in the exception table under
1654  *      the node with longest prefix length.
1655  */
1656
1657
1658 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1659                                        const struct in6_addr *addr,
1660                                        int plen, int offset,
1661                                        bool exact_match)
1662 {
1663         struct fib6_node *fn, *prev = NULL;
1664
1665         for (fn = root; fn ; ) {
1666                 struct fib6_info *leaf = rcu_dereference(fn->leaf);
1667                 struct rt6key *key;
1668
1669                 /* This node is being deleted */
1670                 if (!leaf) {
1671                         if (plen <= fn->fn_bit)
1672                                 goto out;
1673                         else
1674                                 goto next;
1675                 }
1676
1677                 key = (struct rt6key *)((u8 *)leaf + offset);
1678
1679                 /*
1680                  *      Prefix match
1681                  */
1682                 if (plen < fn->fn_bit ||
1683                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1684                         goto out;
1685
1686                 if (plen == fn->fn_bit)
1687                         return fn;
1688
1689                 if (fn->fn_flags & RTN_RTINFO)
1690                         prev = fn;
1691
1692 next:
1693                 /*
1694                  *      We have more bits to go
1695                  */
1696                 if (addr_bit_set(addr, fn->fn_bit))
1697                         fn = rcu_dereference(fn->right);
1698                 else
1699                         fn = rcu_dereference(fn->left);
1700         }
1701 out:
1702         if (exact_match)
1703                 return NULL;
1704         else
1705                 return prev;
1706 }
1707
1708 struct fib6_node *fib6_locate(struct fib6_node *root,
1709                               const struct in6_addr *daddr, int dst_len,
1710                               const struct in6_addr *saddr, int src_len,
1711                               bool exact_match)
1712 {
1713         struct fib6_node *fn;
1714
1715         fn = fib6_locate_1(root, daddr, dst_len,
1716                            offsetof(struct fib6_info, fib6_dst),
1717                            exact_match);
1718
1719 #ifdef CONFIG_IPV6_SUBTREES
1720         if (src_len) {
1721                 WARN_ON(saddr == NULL);
1722                 if (fn) {
1723                         struct fib6_node *subtree = FIB6_SUBTREE(fn);
1724
1725                         if (subtree) {
1726                                 fn = fib6_locate_1(subtree, saddr, src_len,
1727                                            offsetof(struct fib6_info, fib6_src),
1728                                            exact_match);
1729                         }
1730                 }
1731         }
1732 #endif
1733
1734         if (fn && fn->fn_flags & RTN_RTINFO)
1735                 return fn;
1736
1737         return NULL;
1738 }
1739
1740
1741 /*
1742  *      Deletion
1743  *
1744  */
1745
1746 static struct fib6_info *fib6_find_prefix(struct net *net,
1747                                          struct fib6_table *table,
1748                                          struct fib6_node *fn)
1749 {
1750         struct fib6_node *child_left, *child_right;
1751
1752         if (fn->fn_flags & RTN_ROOT)
1753                 return net->ipv6.fib6_null_entry;
1754
1755         while (fn) {
1756                 child_left = rcu_dereference_protected(fn->left,
1757                                     lockdep_is_held(&table->tb6_lock));
1758                 child_right = rcu_dereference_protected(fn->right,
1759                                     lockdep_is_held(&table->tb6_lock));
1760                 if (child_left)
1761                         return rcu_dereference_protected(child_left->leaf,
1762                                         lockdep_is_held(&table->tb6_lock));
1763                 if (child_right)
1764                         return rcu_dereference_protected(child_right->leaf,
1765                                         lockdep_is_held(&table->tb6_lock));
1766
1767                 fn = FIB6_SUBTREE(fn);
1768         }
1769         return NULL;
1770 }
1771
1772 /*
1773  *      Called to trim the tree of intermediate nodes when possible. "fn"
1774  *      is the node we want to try and remove.
1775  *      Need to own table->tb6_lock
1776  */
1777
1778 static struct fib6_node *fib6_repair_tree(struct net *net,
1779                                           struct fib6_table *table,
1780                                           struct fib6_node *fn)
1781 {
1782         int children;
1783         int nstate;
1784         struct fib6_node *child;
1785         struct fib6_walker *w;
1786         int iter = 0;
1787
1788         /* Set fn->leaf to null_entry for root node. */
1789         if (fn->fn_flags & RTN_TL_ROOT) {
1790                 rcu_assign_pointer(fn->leaf, net->ipv6.fib6_null_entry);
1791                 return fn;
1792         }
1793
1794         for (;;) {
1795                 struct fib6_node *fn_r = rcu_dereference_protected(fn->right,
1796                                             lockdep_is_held(&table->tb6_lock));
1797                 struct fib6_node *fn_l = rcu_dereference_protected(fn->left,
1798                                             lockdep_is_held(&table->tb6_lock));
1799                 struct fib6_node *pn = rcu_dereference_protected(fn->parent,
1800                                             lockdep_is_held(&table->tb6_lock));
1801                 struct fib6_node *pn_r = rcu_dereference_protected(pn->right,
1802                                             lockdep_is_held(&table->tb6_lock));
1803                 struct fib6_node *pn_l = rcu_dereference_protected(pn->left,
1804                                             lockdep_is_held(&table->tb6_lock));
1805                 struct fib6_info *fn_leaf = rcu_dereference_protected(fn->leaf,
1806                                             lockdep_is_held(&table->tb6_lock));
1807                 struct fib6_info *pn_leaf = rcu_dereference_protected(pn->leaf,
1808                                             lockdep_is_held(&table->tb6_lock));
1809                 struct fib6_info *new_fn_leaf;
1810
1811                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1812                 iter++;
1813
1814                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1815                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1816                 WARN_ON(fn_leaf);
1817
1818                 children = 0;
1819                 child = NULL;
1820                 if (fn_r) {
1821                         child = fn_r;
1822                         children |= 1;
1823                 }
1824                 if (fn_l) {
1825                         child = fn_l;
1826                         children |= 2;
1827                 }
1828
1829                 if (children == 3 || FIB6_SUBTREE(fn)
1830 #ifdef CONFIG_IPV6_SUBTREES
1831                     /* Subtree root (i.e. fn) may have one child */
1832                     || (children && fn->fn_flags & RTN_ROOT)
1833 #endif
1834                     ) {
1835                         new_fn_leaf = fib6_find_prefix(net, table, fn);
1836 #if RT6_DEBUG >= 2
1837                         if (!new_fn_leaf) {
1838                                 WARN_ON(!new_fn_leaf);
1839                                 new_fn_leaf = net->ipv6.fib6_null_entry;
1840                         }
1841 #endif
1842                         fib6_info_hold(new_fn_leaf);
1843                         rcu_assign_pointer(fn->leaf, new_fn_leaf);
1844                         return pn;
1845                 }
1846
1847 #ifdef CONFIG_IPV6_SUBTREES
1848                 if (FIB6_SUBTREE(pn) == fn) {
1849                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1850                         RCU_INIT_POINTER(pn->subtree, NULL);
1851                         nstate = FWS_L;
1852                 } else {
1853                         WARN_ON(fn->fn_flags & RTN_ROOT);
1854 #endif
1855                         if (pn_r == fn)
1856                                 rcu_assign_pointer(pn->right, child);
1857                         else if (pn_l == fn)
1858                                 rcu_assign_pointer(pn->left, child);
1859 #if RT6_DEBUG >= 2
1860                         else
1861                                 WARN_ON(1);
1862 #endif
1863                         if (child)
1864                                 rcu_assign_pointer(child->parent, pn);
1865                         nstate = FWS_R;
1866 #ifdef CONFIG_IPV6_SUBTREES
1867                 }
1868 #endif
1869
1870                 read_lock(&net->ipv6.fib6_walker_lock);
1871                 FOR_WALKERS(net, w) {
1872                         if (!child) {
1873                                 if (w->node == fn) {
1874                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1875                                         w->node = pn;
1876                                         w->state = nstate;
1877                                 }
1878                         } else {
1879                                 if (w->node == fn) {
1880                                         w->node = child;
1881                                         if (children&2) {
1882                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1883                                                 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1884                                         } else {
1885                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1886                                                 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1887                                         }
1888                                 }
1889                         }
1890                 }
1891                 read_unlock(&net->ipv6.fib6_walker_lock);
1892
1893                 node_free(net, fn);
1894                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1895                         return pn;
1896
1897                 RCU_INIT_POINTER(pn->leaf, NULL);
1898                 fib6_info_release(pn_leaf);
1899                 fn = pn;
1900         }
1901 }
1902
1903 static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
1904                            struct fib6_info __rcu **rtp, struct nl_info *info)
1905 {
1906         struct fib6_info *leaf, *replace_rt = NULL;
1907         struct fib6_walker *w;
1908         struct fib6_info *rt = rcu_dereference_protected(*rtp,
1909                                     lockdep_is_held(&table->tb6_lock));
1910         struct net *net = info->nl_net;
1911         bool notify_del = false;
1912
1913         RT6_TRACE("fib6_del_route\n");
1914
1915         /* If the deleted route is the first in the node and it is not part of
1916          * a multipath route, then we need to replace it with the next route
1917          * in the node, if exists.
1918          */
1919         leaf = rcu_dereference_protected(fn->leaf,
1920                                          lockdep_is_held(&table->tb6_lock));
1921         if (leaf == rt && !rt->fib6_nsiblings) {
1922                 if (rcu_access_pointer(rt->fib6_next))
1923                         replace_rt = rcu_dereference_protected(rt->fib6_next,
1924                                             lockdep_is_held(&table->tb6_lock));
1925                 else
1926                         notify_del = true;
1927         }
1928
1929         /* Unlink it */
1930         *rtp = rt->fib6_next;
1931         rt->fib6_node = NULL;
1932         net->ipv6.rt6_stats->fib_rt_entries--;
1933         net->ipv6.rt6_stats->fib_discarded_routes++;
1934
1935         /* Reset round-robin state, if necessary */
1936         if (rcu_access_pointer(fn->rr_ptr) == rt)
1937                 fn->rr_ptr = NULL;
1938
1939         /* Remove this entry from other siblings */
1940         if (rt->fib6_nsiblings) {
1941                 struct fib6_info *sibling, *next_sibling;
1942
1943                 /* The route is deleted from a multipath route. If this
1944                  * multipath route is the first route in the node, then we need
1945                  * to emit a delete notification. Otherwise, we need to skip
1946                  * the notification.
1947                  */
1948                 if (rt->fib6_metric == leaf->fib6_metric &&
1949                     rt6_qualify_for_ecmp(leaf))
1950                         notify_del = true;
1951                 list_for_each_entry_safe(sibling, next_sibling,
1952                                          &rt->fib6_siblings, fib6_siblings)
1953                         sibling->fib6_nsiblings--;
1954                 rt->fib6_nsiblings = 0;
1955                 list_del_init(&rt->fib6_siblings);
1956                 rt6_multipath_rebalance(next_sibling);
1957         }
1958
1959         /* Adjust walkers */
1960         read_lock(&net->ipv6.fib6_walker_lock);
1961         FOR_WALKERS(net, w) {
1962                 if (w->state == FWS_C && w->leaf == rt) {
1963                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1964                         w->leaf = rcu_dereference_protected(rt->fib6_next,
1965                                             lockdep_is_held(&table->tb6_lock));
1966                         if (!w->leaf)
1967                                 w->state = FWS_U;
1968                 }
1969         }
1970         read_unlock(&net->ipv6.fib6_walker_lock);
1971
1972         /* If it was last route, call fib6_repair_tree() to:
1973          * 1. For root node, put back null_entry as how the table was created.
1974          * 2. For other nodes, expunge its radix tree node.
1975          */
1976         if (!rcu_access_pointer(fn->leaf)) {
1977                 if (!(fn->fn_flags & RTN_TL_ROOT)) {
1978                         fn->fn_flags &= ~RTN_RTINFO;
1979                         net->ipv6.rt6_stats->fib_route_nodes--;
1980                 }
1981                 fn = fib6_repair_tree(net, table, fn);
1982         }
1983
1984         fib6_purge_rt(rt, fn, net);
1985
1986         if (!info->skip_notify_kernel) {
1987                 if (notify_del)
1988                         call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
1989                                                   rt, NULL);
1990                 else if (replace_rt)
1991                         call_fib6_entry_notifiers_replace(net, replace_rt);
1992         }
1993         if (!info->skip_notify)
1994                 inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
1995
1996         fib6_info_release(rt);
1997 }
1998
1999 /* Need to own table->tb6_lock */
2000 int fib6_del(struct fib6_info *rt, struct nl_info *info)
2001 {
2002         struct net *net = info->nl_net;
2003         struct fib6_info __rcu **rtp;
2004         struct fib6_info __rcu **rtp_next;
2005         struct fib6_table *table;
2006         struct fib6_node *fn;
2007
2008         if (rt == net->ipv6.fib6_null_entry)
2009                 return -ENOENT;
2010
2011         table = rt->fib6_table;
2012         fn = rcu_dereference_protected(rt->fib6_node,
2013                                        lockdep_is_held(&table->tb6_lock));
2014         if (!fn)
2015                 return -ENOENT;
2016
2017         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
2018
2019         /*
2020          *      Walk the leaf entries looking for ourself
2021          */
2022
2023         for (rtp = &fn->leaf; *rtp; rtp = rtp_next) {
2024                 struct fib6_info *cur = rcu_dereference_protected(*rtp,
2025                                         lockdep_is_held(&table->tb6_lock));
2026                 if (rt == cur) {
2027                         if (fib6_requires_src(cur))
2028                                 fib6_routes_require_src_dec(info->nl_net);
2029                         fib6_del_route(table, fn, rtp, info);
2030                         return 0;
2031                 }
2032                 rtp_next = &cur->fib6_next;
2033         }
2034         return -ENOENT;
2035 }
2036
2037 /*
2038  *      Tree traversal function.
2039  *
2040  *      Certainly, it is not interrupt safe.
2041  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
2042  *      It means, that we can modify tree during walking
2043  *      and use this function for garbage collection, clone pruning,
2044  *      cleaning tree when a device goes down etc. etc.
2045  *
2046  *      It guarantees that every node will be traversed,
2047  *      and that it will be traversed only once.
2048  *
2049  *      Callback function w->func may return:
2050  *      0 -> continue walking.
2051  *      positive value -> walking is suspended (used by tree dumps,
2052  *      and probably by gc, if it will be split to several slices)
2053  *      negative value -> terminate walking.
2054  *
2055  *      The function itself returns:
2056  *      0   -> walk is complete.
2057  *      >0  -> walk is incomplete (i.e. suspended)
2058  *      <0  -> walk is terminated by an error.
2059  *
2060  *      This function is called with tb6_lock held.
2061  */
2062
2063 static int fib6_walk_continue(struct fib6_walker *w)
2064 {
2065         struct fib6_node *fn, *pn, *left, *right;
2066
2067         /* w->root should always be table->tb6_root */
2068         WARN_ON_ONCE(!(w->root->fn_flags & RTN_TL_ROOT));
2069
2070         for (;;) {
2071                 fn = w->node;
2072                 if (!fn)
2073                         return 0;
2074
2075                 switch (w->state) {
2076 #ifdef CONFIG_IPV6_SUBTREES
2077                 case FWS_S:
2078                         if (FIB6_SUBTREE(fn)) {
2079                                 w->node = FIB6_SUBTREE(fn);
2080                                 continue;
2081                         }
2082                         w->state = FWS_L;
2083                         fallthrough;
2084 #endif
2085                 case FWS_L:
2086                         left = rcu_dereference_protected(fn->left, 1);
2087                         if (left) {
2088                                 w->node = left;
2089                                 w->state = FWS_INIT;
2090                                 continue;
2091                         }
2092                         w->state = FWS_R;
2093                         fallthrough;
2094                 case FWS_R:
2095                         right = rcu_dereference_protected(fn->right, 1);
2096                         if (right) {
2097                                 w->node = right;
2098                                 w->state = FWS_INIT;
2099                                 continue;
2100                         }
2101                         w->state = FWS_C;
2102                         w->leaf = rcu_dereference_protected(fn->leaf, 1);
2103                         fallthrough;
2104                 case FWS_C:
2105                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
2106                                 int err;
2107
2108                                 if (w->skip) {
2109                                         w->skip--;
2110                                         goto skip;
2111                                 }
2112
2113                                 err = w->func(w);
2114                                 if (err)
2115                                         return err;
2116
2117                                 w->count++;
2118                                 continue;
2119                         }
2120 skip:
2121                         w->state = FWS_U;
2122                         fallthrough;
2123                 case FWS_U:
2124                         if (fn == w->root)
2125                                 return 0;
2126                         pn = rcu_dereference_protected(fn->parent, 1);
2127                         left = rcu_dereference_protected(pn->left, 1);
2128                         right = rcu_dereference_protected(pn->right, 1);
2129                         w->node = pn;
2130 #ifdef CONFIG_IPV6_SUBTREES
2131                         if (FIB6_SUBTREE(pn) == fn) {
2132                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
2133                                 w->state = FWS_L;
2134                                 continue;
2135                         }
2136 #endif
2137                         if (left == fn) {
2138                                 w->state = FWS_R;
2139                                 continue;
2140                         }
2141                         if (right == fn) {
2142                                 w->state = FWS_C;
2143                                 w->leaf = rcu_dereference_protected(w->node->leaf, 1);
2144                                 continue;
2145                         }
2146 #if RT6_DEBUG >= 2
2147                         WARN_ON(1);
2148 #endif
2149                 }
2150         }
2151 }
2152
2153 static int fib6_walk(struct net *net, struct fib6_walker *w)
2154 {
2155         int res;
2156
2157         w->state = FWS_INIT;
2158         w->node = w->root;
2159
2160         fib6_walker_link(net, w);
2161         res = fib6_walk_continue(w);
2162         if (res <= 0)
2163                 fib6_walker_unlink(net, w);
2164         return res;
2165 }
2166
2167 static int fib6_clean_node(struct fib6_walker *w)
2168 {
2169         int res;
2170         struct fib6_info *rt;
2171         struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
2172         struct nl_info info = {
2173                 .nl_net = c->net,
2174                 .skip_notify = c->skip_notify,
2175         };
2176
2177         if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
2178             READ_ONCE(w->node->fn_sernum) != c->sernum)
2179                 WRITE_ONCE(w->node->fn_sernum, c->sernum);
2180
2181         if (!c->func) {
2182                 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
2183                 w->leaf = NULL;
2184                 return 0;
2185         }
2186
2187         for_each_fib6_walker_rt(w) {
2188                 res = c->func(rt, c->arg);
2189                 if (res == -1) {
2190                         w->leaf = rt;
2191                         res = fib6_del(rt, &info);
2192                         if (res) {
2193 #if RT6_DEBUG >= 2
2194                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
2195                                          __func__, rt,
2196                                          rcu_access_pointer(rt->fib6_node),
2197                                          res);
2198 #endif
2199                                 continue;
2200                         }
2201                         return 0;
2202                 } else if (res == -2) {
2203                         if (WARN_ON(!rt->fib6_nsiblings))
2204                                 continue;
2205                         rt = list_last_entry(&rt->fib6_siblings,
2206                                              struct fib6_info, fib6_siblings);
2207                         continue;
2208                 }
2209                 WARN_ON(res != 0);
2210         }
2211         w->leaf = rt;
2212         return 0;
2213 }
2214
2215 /*
2216  *      Convenient frontend to tree walker.
2217  *
2218  *      func is called on each route.
2219  *              It may return -2 -> skip multipath route.
2220  *                            -1 -> delete this route.
2221  *                            0  -> continue walking
2222  */
2223
2224 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
2225                             int (*func)(struct fib6_info *, void *arg),
2226                             int sernum, void *arg, bool skip_notify)
2227 {
2228         struct fib6_cleaner c;
2229
2230         c.w.root = root;
2231         c.w.func = fib6_clean_node;
2232         c.w.count = 0;
2233         c.w.skip = 0;
2234         c.w.skip_in_node = 0;
2235         c.func = func;
2236         c.sernum = sernum;
2237         c.arg = arg;
2238         c.net = net;
2239         c.skip_notify = skip_notify;
2240
2241         fib6_walk(net, &c.w);
2242 }
2243
2244 static void __fib6_clean_all(struct net *net,
2245                              int (*func)(struct fib6_info *, void *),
2246                              int sernum, void *arg, bool skip_notify)
2247 {
2248         struct fib6_table *table;
2249         struct hlist_head *head;
2250         unsigned int h;
2251
2252         rcu_read_lock();
2253         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
2254                 head = &net->ipv6.fib_table_hash[h];
2255                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
2256                         spin_lock_bh(&table->tb6_lock);
2257                         fib6_clean_tree(net, &table->tb6_root,
2258                                         func, sernum, arg, skip_notify);
2259                         spin_unlock_bh(&table->tb6_lock);
2260                 }
2261         }
2262         rcu_read_unlock();
2263 }
2264
2265 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *),
2266                     void *arg)
2267 {
2268         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, false);
2269 }
2270
2271 void fib6_clean_all_skip_notify(struct net *net,
2272                                 int (*func)(struct fib6_info *, void *),
2273                                 void *arg)
2274 {
2275         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, true);
2276 }
2277
2278 static void fib6_flush_trees(struct net *net)
2279 {
2280         int new_sernum = fib6_new_sernum(net);
2281
2282         __fib6_clean_all(net, NULL, new_sernum, NULL, false);
2283 }
2284
2285 /*
2286  *      Garbage collection
2287  */
2288
2289 static int fib6_age(struct fib6_info *rt, void *arg)
2290 {
2291         struct fib6_gc_args *gc_args = arg;
2292         unsigned long now = jiffies;
2293
2294         /*
2295          *      check addrconf expiration here.
2296          *      Routes are expired even if they are in use.
2297          */
2298
2299         if (rt->fib6_flags & RTF_EXPIRES && rt->expires) {
2300                 if (time_after(now, rt->expires)) {
2301                         RT6_TRACE("expiring %p\n", rt);
2302                         return -1;
2303                 }
2304                 gc_args->more++;
2305         }
2306
2307         /*      Also age clones in the exception table.
2308          *      Note, that clones are aged out
2309          *      only if they are not in use now.
2310          */
2311         rt6_age_exceptions(rt, gc_args, now);
2312
2313         return 0;
2314 }
2315
2316 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
2317 {
2318         struct fib6_gc_args gc_args;
2319         unsigned long now;
2320
2321         if (force) {
2322                 spin_lock_bh(&net->ipv6.fib6_gc_lock);
2323         } else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
2324                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
2325                 return;
2326         }
2327         gc_args.timeout = expires ? (int)expires :
2328                           net->ipv6.sysctl.ip6_rt_gc_interval;
2329         gc_args.more = 0;
2330
2331         fib6_clean_all(net, fib6_age, &gc_args);
2332         now = jiffies;
2333         net->ipv6.ip6_rt_last_gc = now;
2334
2335         if (gc_args.more)
2336                 mod_timer(&net->ipv6.ip6_fib_timer,
2337                           round_jiffies(now
2338                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
2339         else
2340                 del_timer(&net->ipv6.ip6_fib_timer);
2341         spin_unlock_bh(&net->ipv6.fib6_gc_lock);
2342 }
2343
2344 static void fib6_gc_timer_cb(struct timer_list *t)
2345 {
2346         struct net *arg = from_timer(arg, t, ipv6.ip6_fib_timer);
2347
2348         fib6_run_gc(0, arg, true);
2349 }
2350
2351 static int __net_init fib6_net_init(struct net *net)
2352 {
2353         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
2354         int err;
2355
2356         err = fib6_notifier_init(net);
2357         if (err)
2358                 return err;
2359
2360         /* Default to 3-tuple */
2361         net->ipv6.sysctl.multipath_hash_fields =
2362                 FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
2363
2364         spin_lock_init(&net->ipv6.fib6_gc_lock);
2365         rwlock_init(&net->ipv6.fib6_walker_lock);
2366         INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
2367         timer_setup(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, 0);
2368
2369         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
2370         if (!net->ipv6.rt6_stats)
2371                 goto out_notifier;
2372
2373         /* Avoid false sharing : Use at least a full cache line */
2374         size = max_t(size_t, size, L1_CACHE_BYTES);
2375
2376         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
2377         if (!net->ipv6.fib_table_hash)
2378                 goto out_rt6_stats;
2379
2380         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
2381                                           GFP_KERNEL);
2382         if (!net->ipv6.fib6_main_tbl)
2383                 goto out_fib_table_hash;
2384
2385         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
2386         rcu_assign_pointer(net->ipv6.fib6_main_tbl->tb6_root.leaf,
2387                            net->ipv6.fib6_null_entry);
2388         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
2389                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2390         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
2391
2392 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2393         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
2394                                            GFP_KERNEL);
2395         if (!net->ipv6.fib6_local_tbl)
2396                 goto out_fib6_main_tbl;
2397         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
2398         rcu_assign_pointer(net->ipv6.fib6_local_tbl->tb6_root.leaf,
2399                            net->ipv6.fib6_null_entry);
2400         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
2401                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2402         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
2403 #endif
2404         fib6_tables_init(net);
2405
2406         return 0;
2407
2408 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2409 out_fib6_main_tbl:
2410         kfree(net->ipv6.fib6_main_tbl);
2411 #endif
2412 out_fib_table_hash:
2413         kfree(net->ipv6.fib_table_hash);
2414 out_rt6_stats:
2415         kfree(net->ipv6.rt6_stats);
2416 out_notifier:
2417         fib6_notifier_exit(net);
2418         return -ENOMEM;
2419 }
2420
2421 static void fib6_net_exit(struct net *net)
2422 {
2423         unsigned int i;
2424
2425         del_timer_sync(&net->ipv6.ip6_fib_timer);
2426
2427         for (i = 0; i < FIB6_TABLE_HASHSZ; i++) {
2428                 struct hlist_head *head = &net->ipv6.fib_table_hash[i];
2429                 struct hlist_node *tmp;
2430                 struct fib6_table *tb;
2431
2432                 hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
2433                         hlist_del(&tb->tb6_hlist);
2434                         fib6_free_table(tb);
2435                 }
2436         }
2437
2438         kfree(net->ipv6.fib_table_hash);
2439         kfree(net->ipv6.rt6_stats);
2440         fib6_notifier_exit(net);
2441 }
2442
2443 static struct pernet_operations fib6_net_ops = {
2444         .init = fib6_net_init,
2445         .exit = fib6_net_exit,
2446 };
2447
2448 int __init fib6_init(void)
2449 {
2450         int ret = -ENOMEM;
2451
2452         fib6_node_kmem = kmem_cache_create("fib6_nodes",
2453                                            sizeof(struct fib6_node), 0,
2454                                            SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
2455                                            NULL);
2456         if (!fib6_node_kmem)
2457                 goto out;
2458
2459         ret = register_pernet_subsys(&fib6_net_ops);
2460         if (ret)
2461                 goto out_kmem_cache_create;
2462
2463         ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETROUTE, NULL,
2464                                    inet6_dump_fib, 0);
2465         if (ret)
2466                 goto out_unregister_subsys;
2467
2468         __fib6_flush_trees = fib6_flush_trees;
2469 out:
2470         return ret;
2471
2472 out_unregister_subsys:
2473         unregister_pernet_subsys(&fib6_net_ops);
2474 out_kmem_cache_create:
2475         kmem_cache_destroy(fib6_node_kmem);
2476         goto out;
2477 }
2478
2479 void fib6_gc_cleanup(void)
2480 {
2481         unregister_pernet_subsys(&fib6_net_ops);
2482         kmem_cache_destroy(fib6_node_kmem);
2483 }
2484
2485 #ifdef CONFIG_PROC_FS
2486 static int ipv6_route_native_seq_show(struct seq_file *seq, void *v)
2487 {
2488         struct fib6_info *rt = v;
2489         struct ipv6_route_iter *iter = seq->private;
2490         struct fib6_nh *fib6_nh = rt->fib6_nh;
2491         unsigned int flags = rt->fib6_flags;
2492         const struct net_device *dev;
2493
2494         if (rt->nh)
2495                 fib6_nh = nexthop_fib6_nh_bh(rt->nh);
2496
2497         seq_printf(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen);
2498
2499 #ifdef CONFIG_IPV6_SUBTREES
2500         seq_printf(seq, "%pi6 %02x ", &rt->fib6_src.addr, rt->fib6_src.plen);
2501 #else
2502         seq_puts(seq, "00000000000000000000000000000000 00 ");
2503 #endif
2504         if (fib6_nh->fib_nh_gw_family) {
2505                 flags |= RTF_GATEWAY;
2506                 seq_printf(seq, "%pi6", &fib6_nh->fib_nh_gw6);
2507         } else {
2508                 seq_puts(seq, "00000000000000000000000000000000");
2509         }
2510
2511         dev = fib6_nh->fib_nh_dev;
2512         seq_printf(seq, " %08x %08x %08x %08x %8s\n",
2513                    rt->fib6_metric, refcount_read(&rt->fib6_ref), 0,
2514                    flags, dev ? dev->name : "");
2515         iter->w.leaf = NULL;
2516         return 0;
2517 }
2518
2519 static int ipv6_route_yield(struct fib6_walker *w)
2520 {
2521         struct ipv6_route_iter *iter = w->args;
2522
2523         if (!iter->skip)
2524                 return 1;
2525
2526         do {
2527                 iter->w.leaf = rcu_dereference_protected(
2528                                 iter->w.leaf->fib6_next,
2529                                 lockdep_is_held(&iter->tbl->tb6_lock));
2530                 iter->skip--;
2531                 if (!iter->skip && iter->w.leaf)
2532                         return 1;
2533         } while (iter->w.leaf);
2534
2535         return 0;
2536 }
2537
2538 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
2539                                       struct net *net)
2540 {
2541         memset(&iter->w, 0, sizeof(iter->w));
2542         iter->w.func = ipv6_route_yield;
2543         iter->w.root = &iter->tbl->tb6_root;
2544         iter->w.state = FWS_INIT;
2545         iter->w.node = iter->w.root;
2546         iter->w.args = iter;
2547         iter->sernum = READ_ONCE(iter->w.root->fn_sernum);
2548         INIT_LIST_HEAD(&iter->w.lh);
2549         fib6_walker_link(net, &iter->w);
2550 }
2551
2552 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
2553                                                     struct net *net)
2554 {
2555         unsigned int h;
2556         struct hlist_node *node;
2557
2558         if (tbl) {
2559                 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
2560                 node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
2561         } else {
2562                 h = 0;
2563                 node = NULL;
2564         }
2565
2566         while (!node && h < FIB6_TABLE_HASHSZ) {
2567                 node = rcu_dereference_bh(
2568                         hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
2569         }
2570         return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
2571 }
2572
2573 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
2574 {
2575         int sernum = READ_ONCE(iter->w.root->fn_sernum);
2576
2577         if (iter->sernum != sernum) {
2578                 iter->sernum = sernum;
2579                 iter->w.state = FWS_INIT;
2580                 iter->w.node = iter->w.root;
2581                 WARN_ON(iter->w.skip);
2582                 iter->w.skip = iter->w.count;
2583         }
2584 }
2585
2586 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2587 {
2588         int r;
2589         struct fib6_info *n;
2590         struct net *net = seq_file_net(seq);
2591         struct ipv6_route_iter *iter = seq->private;
2592
2593         ++(*pos);
2594         if (!v)
2595                 goto iter_table;
2596
2597         n = rcu_dereference_bh(((struct fib6_info *)v)->fib6_next);
2598         if (n)
2599                 return n;
2600
2601 iter_table:
2602         ipv6_route_check_sernum(iter);
2603         spin_lock_bh(&iter->tbl->tb6_lock);
2604         r = fib6_walk_continue(&iter->w);
2605         spin_unlock_bh(&iter->tbl->tb6_lock);
2606         if (r > 0) {
2607                 return iter->w.leaf;
2608         } else if (r < 0) {
2609                 fib6_walker_unlink(net, &iter->w);
2610                 return NULL;
2611         }
2612         fib6_walker_unlink(net, &iter->w);
2613
2614         iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
2615         if (!iter->tbl)
2616                 return NULL;
2617
2618         ipv6_route_seq_setup_walk(iter, net);
2619         goto iter_table;
2620 }
2621
2622 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
2623         __acquires(RCU_BH)
2624 {
2625         struct net *net = seq_file_net(seq);
2626         struct ipv6_route_iter *iter = seq->private;
2627
2628         rcu_read_lock_bh();
2629         iter->tbl = ipv6_route_seq_next_table(NULL, net);
2630         iter->skip = *pos;
2631
2632         if (iter->tbl) {
2633                 loff_t p = 0;
2634
2635                 ipv6_route_seq_setup_walk(iter, net);
2636                 return ipv6_route_seq_next(seq, NULL, &p);
2637         } else {
2638                 return NULL;
2639         }
2640 }
2641
2642 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
2643 {
2644         struct fib6_walker *w = &iter->w;
2645         return w->node && !(w->state == FWS_U && w->node == w->root);
2646 }
2647
2648 static void ipv6_route_native_seq_stop(struct seq_file *seq, void *v)
2649         __releases(RCU_BH)
2650 {
2651         struct net *net = seq_file_net(seq);
2652         struct ipv6_route_iter *iter = seq->private;
2653
2654         if (ipv6_route_iter_active(iter))
2655                 fib6_walker_unlink(net, &iter->w);
2656
2657         rcu_read_unlock_bh();
2658 }
2659
2660 #if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
2661 static int ipv6_route_prog_seq_show(struct bpf_prog *prog,
2662                                     struct bpf_iter_meta *meta,
2663                                     void *v)
2664 {
2665         struct bpf_iter__ipv6_route ctx;
2666
2667         ctx.meta = meta;
2668         ctx.rt = v;
2669         return bpf_iter_run_prog(prog, &ctx);
2670 }
2671
2672 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2673 {
2674         struct ipv6_route_iter *iter = seq->private;
2675         struct bpf_iter_meta meta;
2676         struct bpf_prog *prog;
2677         int ret;
2678
2679         meta.seq = seq;
2680         prog = bpf_iter_get_info(&meta, false);
2681         if (!prog)
2682                 return ipv6_route_native_seq_show(seq, v);
2683
2684         ret = ipv6_route_prog_seq_show(prog, &meta, v);
2685         iter->w.leaf = NULL;
2686
2687         return ret;
2688 }
2689
2690 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2691 {
2692         struct bpf_iter_meta meta;
2693         struct bpf_prog *prog;
2694
2695         if (!v) {
2696                 meta.seq = seq;
2697                 prog = bpf_iter_get_info(&meta, true);
2698                 if (prog)
2699                         (void)ipv6_route_prog_seq_show(prog, &meta, v);
2700         }
2701
2702         ipv6_route_native_seq_stop(seq, v);
2703 }
2704 #else
2705 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2706 {
2707         return ipv6_route_native_seq_show(seq, v);
2708 }
2709
2710 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2711 {
2712         ipv6_route_native_seq_stop(seq, v);
2713 }
2714 #endif
2715
2716 const struct seq_operations ipv6_route_seq_ops = {
2717         .start  = ipv6_route_seq_start,
2718         .next   = ipv6_route_seq_next,
2719         .stop   = ipv6_route_seq_stop,
2720         .show   = ipv6_route_seq_show
2721 };
2722 #endif /* CONFIG_PROC_FS */