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/errno.h>
  19 #include <linux/types.h>
  20 #include <linux/net.h>
  21 #include <linux/route.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/in6.h>
  24 #include <linux/init.h>
  25 #include <linux/list.h>
  26 #include <linux/slab.h>
  27
  28 #include <net/ip.h>
  29 #include <net/ipv6.h>
  30 #include <net/ndisc.h>
  31 #include <net/addrconf.h>
  32 #include <net/lwtunnel.h>
  33 #include <net/fib_notifier.h>
  34
  35 #include <net/ip_fib.h>
  36 #include <net/ip6_fib.h>
  37 #include <net/ip6_route.h>
  38
  39 static struct kmem_cache *fib6_node_kmem __read_mostly;
  40
  41 struct fib6_cleaner {
  42         struct fib6_walker w;
  43         struct net *net;
  44         int (*func)(struct fib6_info *, void *arg);
  45         int sernum;
  46         void *arg;
  47         bool skip_notify;
  48 };
  49
  50 #ifdef CONFIG_IPV6_SUBTREES
  51 #define FWS_INIT FWS_S
  52 #else
  53 #define FWS_INIT FWS_L
  54 #endif
  55
  56 static struct fib6_info *fib6_find_prefix(struct net *net,
  57                                          struct fib6_table *table,
  58                                          struct fib6_node *fn);
  59 static struct fib6_node *fib6_repair_tree(struct net *net,
  60                                           struct fib6_table *table,
  61                                           struct fib6_node *fn);
  62 static int fib6_walk(struct net *net, struct fib6_walker *w);
  63 static int fib6_walk_continue(struct fib6_walker *w);
  64
  65 /*
  66  *      A routing update causes an increase of the serial number on the
  67  *      affected subtree. This allows for cached routes to be asynchronously
  68  *      tested when modifications are made to the destination cache as a
  69  *      result of redirects, path MTU changes, etc.
  70  */
  71
  72 static void fib6_gc_timer_cb(struct timer_list *t);
  73
  74 #define FOR_WALKERS(net, w) \
  75         list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)
  76
  77 static void fib6_walker_link(struct net *net, struct fib6_walker *w)
  78 {
  79         write_lock_bh(&net->ipv6.fib6_walker_lock);
  80         list_add(&w->lh, &net->ipv6.fib6_walkers);
  81         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  82 }
  83
  84 static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
  85 {
  86         write_lock_bh(&net->ipv6.fib6_walker_lock);
  87         list_del(&w->lh);
  88         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  89 }
  90
  91 static int fib6_new_sernum(struct net *net)
  92 {
  93         int new, old;
  94
  95         do {
  96                 old = atomic_read(&net->ipv6.fib6_sernum);
  97                 new = old < INT_MAX ? old + 1 : 1;
  98         } while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
  99                                 old, new) != old);
 100         return new;
 101 }
 102
 103 enum {
 104         FIB6_NO_SERNUM_CHANGE = 0,
 105 };
 106
 107 void fib6_update_sernum(struct net *net, struct fib6_info *f6i)
 108 {
 109         struct fib6_node *fn;
 110
 111         fn = rcu_dereference_protected(f6i->fib6_node,
 112                         lockdep_is_held(&f6i->fib6_table->tb6_lock));
 113         if (fn)
 114                 fn->fn_sernum = fib6_new_sernum(net);
 115 }
 116
 117 /*
 118  *      Auxiliary address test functions for the radix tree.
 119  *
 120  *      These assume a 32bit processor (although it will work on
 121  *      64bit processors)
 122  */
 123
 124 /*
 125  *      test bit
 126  */
 127 #if defined(__LITTLE_ENDIAN)
 128 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
 129 #else
 130 # define BITOP_BE32_SWIZZLE     0
 131 #endif
 132
 133 static __be32 addr_bit_set(const void *token, int fn_bit)
 134 {
 135         const __be32 *addr = token;
 136         /*
 137          * Here,
 138          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
 139          * is optimized version of
 140          *      htonl(1 << ((~fn_bit)&0x1F))
 141          * See include/asm-generic/bitops/le.h.
 142          */
 143         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
 144                addr[fn_bit >> 5];
 145 }
 146
 147 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh)
 148 {
 149         struct fib6_info *f6i;
 150         size_t sz = sizeof(*f6i);
 151
 152         if (with_fib6_nh)
 153                 sz += sizeof(struct fib6_nh);
 154
 155         f6i = kzalloc(sz, gfp_flags);
 156         if (!f6i)
 157                 return NULL;
 158
 159         /* fib6_siblings is a union with nh_list, so this initializes both */
 160         INIT_LIST_HEAD(&f6i->fib6_siblings);
 161         refcount_set(&f6i->fib6_ref, 1);
 162
 163         return f6i;
 164 }
 165
 166 void fib6_info_destroy_rcu(struct rcu_head *head)
 167 {
 168         struct fib6_info *f6i = container_of(head, struct fib6_info, rcu);
 169
 170         WARN_ON(f6i->fib6_node);
 171
 172         if (f6i->nh)
 173                 nexthop_put(f6i->nh);
 174         else
 175                 fib6_nh_release(f6i->fib6_nh);
 176
 177         ip_fib_metrics_put(f6i->fib6_metrics);
 178         kfree(f6i);
 179 }
 180 EXPORT_SYMBOL_GPL(fib6_info_destroy_rcu);
 181
 182 static struct fib6_node *node_alloc(struct net *net)
 183 {
 184         struct fib6_node *fn;
 185
 186         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 187         if (fn)
 188                 net->ipv6.rt6_stats->fib_nodes++;
 189
 190         return fn;
 191 }
 192
 193 static void node_free_immediate(struct net *net, struct fib6_node *fn)
 194 {
 195         kmem_cache_free(fib6_node_kmem, fn);
 196         net->ipv6.rt6_stats->fib_nodes--;
 197 }
 198
 199 static void node_free_rcu(struct rcu_head *head)
 200 {
 201         struct fib6_node *fn = container_of(head, struct fib6_node, rcu);
 202
 203         kmem_cache_free(fib6_node_kmem, fn);
 204 }
 205
 206 static void node_free(struct net *net, struct fib6_node *fn)
 207 {
 208         call_rcu(&fn->rcu, node_free_rcu);
 209         net->ipv6.rt6_stats->fib_nodes--;
 210 }
 211
 212 static void fib6_free_table(struct fib6_table *table)
 213 {
 214         inetpeer_invalidate_tree(&table->tb6_peers);
 215         kfree(table);
 216 }
 217
 218 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 219 {
 220         unsigned int h;
 221
 222         /*
 223          * Initialize table lock at a single place to give lockdep a key,
 224          * tables aren't visible prior to being linked to the list.
 225          */
 226         spin_lock_init(&tb->tb6_lock);
 227         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 228
 229         /*
 230          * No protection necessary, this is the only list mutatation
 231          * operation, tables never disappear once they exist.
 232          */
 233         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 234 }
 235
 236 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 237
 238 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 239 {
 240         struct fib6_table *table;
 241
 242         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 243         if (table) {
 244                 table->tb6_id = id;
 245                 rcu_assign_pointer(table->tb6_root.leaf,
 246                                    net->ipv6.fib6_null_entry);
 247                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 248                 inet_peer_base_init(&table->tb6_peers);
 249         }
 250
 251         return table;
 252 }
 253
 254 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 255 {
 256         struct fib6_table *tb;
 257
 258         if (id == 0)
 259                 id = RT6_TABLE_MAIN;
 260         tb = fib6_get_table(net, id);
 261         if (tb)
 262                 return tb;
 263
 264         tb = fib6_alloc_table(net, id);
 265         if (tb)
 266                 fib6_link_table(net, tb);
 267
 268         return tb;
 269 }
 270 EXPORT_SYMBOL_GPL(fib6_new_table);
 271
 272 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 273 {
 274         struct fib6_table *tb;
 275         struct hlist_head *head;
 276         unsigned int h;
 277
 278         if (id == 0)
 279                 id = RT6_TABLE_MAIN;
 280         h = id & (FIB6_TABLE_HASHSZ - 1);
 281         rcu_read_lock();
 282         head = &net->ipv6.fib_table_hash[h];
 283         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 284                 if (tb->tb6_id == id) {
 285                         rcu_read_unlock();
 286                         return tb;
 287                 }
 288         }
 289         rcu_read_unlock();
 290
 291         return NULL;
 292 }
 293 EXPORT_SYMBOL_GPL(fib6_get_table);
 294
 295 static void __net_init fib6_tables_init(struct net *net)
 296 {
 297         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 298         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 299 }
 300 #else
 301
 302 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 303 {
 304         return fib6_get_table(net, id);
 305 }
 306
 307 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 308 {
 309           return net->ipv6.fib6_main_tbl;
 310 }
 311
 312 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 313                                    const struct sk_buff *skb,
 314                                    int flags, pol_lookup_t lookup)
 315 {
 316         struct rt6_info *rt;
 317
 318         rt = pol_lookup_func(lookup,
 319                         net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
 320         if (rt->dst.error == -EAGAIN) {
 321                 ip6_rt_put_flags(rt, flags);
 322                 rt = net->ipv6.ip6_null_entry;
 323                 if (!(flags & RT6_LOOKUP_F_DST_NOREF))
 324                         dst_hold(&rt->dst);
 325         }
 326
 327         return &rt->dst;
 328 }
 329
 330 /* called with rcu lock held; no reference taken on fib6_info */
 331 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 332                 struct fib6_result *res, int flags)
 333 {
 334         return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6,
 335                                  res, flags);
 336 }
 337
 338 static void __net_init fib6_tables_init(struct net *net)
 339 {
 340         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 341 }
 342
 343 #endif
 344
 345 unsigned int fib6_tables_seq_read(struct net *net)
 346 {
 347         unsigned int h, fib_seq = 0;
 348
 349         rcu_read_lock();
 350         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
 351                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
 352                 struct fib6_table *tb;
 353
 354                 hlist_for_each_entry_rcu(tb, head, tb6_hlist)
 355                         fib_seq += tb->fib_seq;
 356         }
 357         rcu_read_unlock();
 358
 359         return fib_seq;
 360 }
 361
 362 static int call_fib6_entry_notifier(struct notifier_block *nb,
 363                                     enum fib_event_type event_type,
 364                                     struct fib6_info *rt,
 365                                     struct netlink_ext_ack *extack)
 366 {
 367         struct fib6_entry_notifier_info info = {
 368                 .info.extack = extack,
 369                 .rt = rt,
 370         };
 371
 372         return call_fib6_notifier(nb, event_type, &info.info);
 373 }
 374
 375 static int call_fib6_multipath_entry_notifier(struct notifier_block *nb,
 376                                               enum fib_event_type event_type,
 377                                               struct fib6_info *rt,
 378                                               unsigned int nsiblings,
 379                                               struct netlink_ext_ack *extack)
 380 {
 381         struct fib6_entry_notifier_info info = {
 382                 .info.extack = extack,
 383                 .rt = rt,
 384                 .nsiblings = nsiblings,
 385         };
 386
 387         return call_fib6_notifier(nb, event_type, &info.info);
 388 }
 389
 390 int call_fib6_entry_notifiers(struct net *net,
 391                               enum fib_event_type event_type,
 392                               struct fib6_info *rt,
 393                               struct netlink_ext_ack *extack)
 394 {
 395         struct fib6_entry_notifier_info info = {
 396                 .info.extack = extack,
 397                 .rt = rt,
 398         };
 399
 400         rt->fib6_table->fib_seq++;
 401         return call_fib6_notifiers(net, event_type, &info.info);
 402 }
 403
 404 int call_fib6_multipath_entry_notifiers(struct net *net,
 405                                         enum fib_event_type event_type,
 406                                         struct fib6_info *rt,
 407                                         unsigned int nsiblings,
 408                                         struct netlink_ext_ack *extack)
 409 {
 410         struct fib6_entry_notifier_info info = {
 411                 .info.extack = extack,
 412                 .rt = rt,
 413                 .nsiblings = nsiblings,
 414         };
 415
 416         rt->fib6_table->fib_seq++;
 417         return call_fib6_notifiers(net, event_type, &info.info);
 418 }
 419
 420 int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt)
 421 {
 422         struct fib6_entry_notifier_info info = {
 423                 .rt = rt,
 424                 .nsiblings = rt->fib6_nsiblings,
 425         };
 426
 427         rt->fib6_table->fib_seq++;
 428         return call_fib6_notifiers(net, FIB_EVENT_ENTRY_REPLACE, &info.info);
 429 }
 430
 431 struct fib6_dump_arg {
 432         struct net *net;
 433         struct notifier_block *nb;
 434         struct netlink_ext_ack *extack;
 435 };
 436
 437 static int fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
 438 {
 439         enum fib_event_type fib_event = FIB_EVENT_ENTRY_REPLACE;
 440         int err;
 441
 442         if (!rt || rt == arg->net->ipv6.fib6_null_entry)
 443                 return 0;
 444
 445         if (rt->fib6_nsiblings)
 446                 err = call_fib6_multipath_entry_notifier(arg->nb, fib_event,
 447                                                          rt,
 448                                                          rt->fib6_nsiblings,
 449                                                          arg->extack);
 450         else
 451                 err = call_fib6_entry_notifier(arg->nb, fib_event, rt,
 452                                                arg->extack);
 453
 454         return err;
 455 }
 456
 457 static int fib6_node_dump(struct fib6_walker *w)
 458 {
 459         int err;
 460
 461         err = fib6_rt_dump(w->leaf, w->args);
 462         w->leaf = NULL;
 463         return err;
 464 }
 465
 466 static int fib6_table_dump(struct net *net, struct fib6_table *tb,
 467                            struct fib6_walker *w)
 468 {
 469         int err;
 470
 471         w->root = &tb->tb6_root;
 472         spin_lock_bh(&tb->tb6_lock);
 473         err = fib6_walk(net, w);
 474         spin_unlock_bh(&tb->tb6_lock);
 475         return err;
 476 }
 477
 478 /* Called with rcu_read_lock() */
 479 int fib6_tables_dump(struct net *net, struct notifier_block *nb,
 480                      struct netlink_ext_ack *extack)
 481 {
 482         struct fib6_dump_arg arg;
 483         struct fib6_walker *w;
 484         unsigned int h;
 485         int err = 0;
 486
 487         w = kzalloc(sizeof(*w), GFP_ATOMIC);
 488         if (!w)
 489                 return -ENOMEM;
 490
 491         w->func = fib6_node_dump;
 492         arg.net = net;
 493         arg.nb = nb;
 494         arg.extack = extack;
 495         w->args = &arg;
 496
 497         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
 498                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
 499                 struct fib6_table *tb;
 500
 501                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 502                         err = fib6_table_dump(net, tb, w);
 503                         if (err)
 504                                 goto out;
 505                 }
 506         }
 507
 508 out:
 509         kfree(w);
 510
 511         /* The tree traversal function should never return a positive value. */
 512         return err > 0 ? -EINVAL : err;
 513 }
 514
 515 static int fib6_dump_node(struct fib6_walker *w)
 516 {
 517         int res;
 518         struct fib6_info *rt;
 519
 520         for_each_fib6_walker_rt(w) {
 521                 res = rt6_dump_route(rt, w->args, w->skip_in_node);
 522                 if (res >= 0) {
 523                         /* Frame is full, suspend walking */
 524                         w->leaf = rt;
 525
 526                         /* We'll restart from this node, so if some routes were
 527                          * already dumped, skip them next time.
 528                          */
 529                         w->skip_in_node += res;
 530
 531                         return 1;
 532                 }
 533                 w->skip_in_node = 0;
 534
 535                 /* Multipath routes are dumped in one route with the
 536                  * RTA_MULTIPATH attribute. Jump 'rt' to point to the
 537                  * last sibling of this route (no need to dump the
 538                  * sibling routes again)
 539                  */
 540                 if (rt->fib6_nsiblings)
 541                         rt = list_last_entry(&rt->fib6_siblings,
 542                                              struct fib6_info,
 543                                              fib6_siblings);
 544         }
 545         w->leaf = NULL;
 546         return 0;
 547 }
 548
 549 static void fib6_dump_end(struct netlink_callback *cb)
 550 {
 551         struct net *net = sock_net(cb->skb->sk);
 552         struct fib6_walker *w = (void *)cb->args[2];
 553
 554         if (w) {
 555                 if (cb->args[4]) {
 556                         cb->args[4] = 0;
 557                         fib6_walker_unlink(net, w);
 558                 }
 559                 cb->args[2] = 0;
 560                 kfree(w);
 561         }
 562         cb->done = (void *)cb->args[3];
 563         cb->args[1] = 3;
 564 }
 565
 566 static int fib6_dump_done(struct netlink_callback *cb)
 567 {
 568         fib6_dump_end(cb);
 569         return cb->done ? cb->done(cb) : 0;
 570 }
 571
 572 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 573                            struct netlink_callback *cb)
 574 {
 575         struct net *net = sock_net(skb->sk);
 576         struct fib6_walker *w;
 577         int res;
 578
 579         w = (void *)cb->args[2];
 580         w->root = &table->tb6_root;
 581
 582         if (cb->args[4] == 0) {
 583                 w->count = 0;
 584                 w->skip = 0;
 585                 w->skip_in_node = 0;
 586
 587                 spin_lock_bh(&table->tb6_lock);
 588                 res = fib6_walk(net, w);
 589                 spin_unlock_bh(&table->tb6_lock);
 590                 if (res > 0) {
 591                         cb->args[4] = 1;
 592                         cb->args[5] = w->root->fn_sernum;
 593                 }
 594         } else {
 595                 if (cb->args[5] != w->root->fn_sernum) {
 596                         /* Begin at the root if the tree changed */
 597                         cb->args[5] = w->root->fn_sernum;
 598                         w->state = FWS_INIT;
 599                         w->node = w->root;
 600                         w->skip = w->count;
 601                         w->skip_in_node = 0;
 602                 } else
 603                         w->skip = 0;
 604
 605                 spin_lock_bh(&table->tb6_lock);
 606                 res = fib6_walk_continue(w);
 607                 spin_unlock_bh(&table->tb6_lock);
 608                 if (res <= 0) {
 609                         fib6_walker_unlink(net, w);
 610                         cb->args[4] = 0;
 611                 }
 612         }
 613
 614         return res;
 615 }
 616
 617 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 618 {
 619         struct rt6_rtnl_dump_arg arg = { .filter.dump_exceptions = true,
 620                                          .filter.dump_routes = true };
 621         const struct nlmsghdr *nlh = cb->nlh;
 622         struct net *net = sock_net(skb->sk);
 623         unsigned int h, s_h;
 624         unsigned int e = 0, s_e;
 625         struct fib6_walker *w;
 626         struct fib6_table *tb;
 627         struct hlist_head *head;
 628         int res = 0;
 629
 630         if (cb->strict_check) {
 631                 int err;
 632
 633                 err = ip_valid_fib_dump_req(net, nlh, &arg.filter, cb);
 634                 if (err < 0)
 635                         return err;
 636         } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
 637                 struct rtmsg *rtm = nlmsg_data(nlh);
 638
 639                 if (rtm->rtm_flags & RTM_F_PREFIX)
 640                         arg.filter.flags = RTM_F_PREFIX;
 641         }
 642
 643         w = (void *)cb->args[2];
 644         if (!w) {
 645                 /* New dump:
 646                  *
 647                  * 1. hook callback destructor.
 648                  */
 649                 cb->args[3] = (long)cb->done;
 650                 cb->done = fib6_dump_done;
 651
 652                 /*
 653                  * 2. allocate and initialize walker.
 654                  */
 655                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 656                 if (!w)
 657                         return -ENOMEM;
 658                 w->func = fib6_dump_node;
 659                 cb->args[2] = (long)w;
 660         }
 661
 662         arg.skb = skb;
 663         arg.cb = cb;
 664         arg.net = net;
 665         w->args = &arg;
 666
 667         if (arg.filter.table_id) {
 668                 tb = fib6_get_table(net, arg.filter.table_id);
 669                 if (!tb) {
 670                         if (rtnl_msg_family(cb->nlh) != PF_INET6)
 671                                 goto out;
 672
 673                         NL_SET_ERR_MSG_MOD(cb->extack, "FIB table does not exist");
 674                         return -ENOENT;
 675                 }
 676
 677                 if (!cb->args[0]) {
 678                         res = fib6_dump_table(tb, skb, cb);
 679                         if (!res)
 680                                 cb->args[0] = 1;
 681                 }
 682                 goto out;
 683         }
 684
 685         s_h = cb->args[0];
 686         s_e = cb->args[1];
 687
 688         rcu_read_lock();
 689         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 690                 e = 0;
 691                 head = &net->ipv6.fib_table_hash[h];
 692                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 693                         if (e < s_e)
 694                                 goto next;
 695                         res = fib6_dump_table(tb, skb, cb);
 696                         if (res != 0)
 697                                 goto out_unlock;
 698 next:
 699                         e++;
 700                 }
 701         }
 702 out_unlock:
 703         rcu_read_unlock();
 704         cb->args[1] = e;
 705         cb->args[0] = h;
 706 out:
 707         res = res < 0 ? res : skb->len;
 708         if (res <= 0)
 709                 fib6_dump_end(cb);
 710         return res;
 711 }
 712
 713 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val)
 714 {
 715         if (!f6i)
 716                 return;
 717
 718         if (f6i->fib6_metrics == &dst_default_metrics) {
 719                 struct dst_metrics *p = kzalloc(sizeof(*p), GFP_ATOMIC);
 720
 721                 if (!p)
 722                         return;
 723
 724                 refcount_set(&p->refcnt, 1);
 725                 f6i->fib6_metrics = p;
 726         }
 727
 728         f6i->fib6_metrics->metrics[metric - 1] = val;
 729 }
 730
 731 /*
 732  *      Routing Table
 733  *
 734  *      return the appropriate node for a routing tree "add" operation
 735  *      by either creating and inserting or by returning an existing
 736  *      node.
 737  */
 738
 739 static struct fib6_node *fib6_add_1(struct net *net,
 740                                     struct fib6_table *table,
 741                                     struct fib6_node *root,
 742                                     struct in6_addr *addr, int plen,
 743                                     int offset, int allow_create,
 744                                     int replace_required,
 745                                     struct netlink_ext_ack *extack)
 746 {
 747         struct fib6_node *fn, *in, *ln;
 748         struct fib6_node *pn = NULL;
 749         struct rt6key *key;
 750         int     bit;
 751         __be32  dir = 0;
 752
 753         RT6_TRACE("fib6_add_1\n");
 754
 755         /* insert node in tree */
 756
 757         fn = root;
 758
 759         do {
 760                 struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
 761                                             lockdep_is_held(&table->tb6_lock));
 762                 key = (struct rt6key *)((u8 *)leaf + offset);
 763
 764                 /*
 765                  *      Prefix match
 766                  */
 767                 if (plen < fn->fn_bit ||
 768                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 769                         if (!allow_create) {
 770                                 if (replace_required) {
 771                                         NL_SET_ERR_MSG(extack,
 772                                                        "Can not replace route - no match found");
 773                                         pr_warn("Can't replace route, no match found\n");
 774                                         return ERR_PTR(-ENOENT);
 775                                 }
 776                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 777                         }
 778                         goto insert_above;
 779                 }
 780
 781                 /*
 782                  *      Exact match ?
 783                  */
 784
 785                 if (plen == fn->fn_bit) {
 786                         /* clean up an intermediate node */
 787                         if (!(fn->fn_flags & RTN_RTINFO)) {
 788                                 RCU_INIT_POINTER(fn->leaf, NULL);
 789                                 fib6_info_release(leaf);
 790                         /* remove null_entry in the root node */
 791                         } else if (fn->fn_flags & RTN_TL_ROOT &&
 792                                    rcu_access_pointer(fn->leaf) ==
 793                                    net->ipv6.fib6_null_entry) {
 794                                 RCU_INIT_POINTER(fn->leaf, NULL);
 795                         }
 796
 797                         return fn;
 798                 }
 799
 800                 /*
 801                  *      We have more bits to go
 802                  */
 803
 804                 /* Try to walk down on tree. */
 805                 dir = addr_bit_set(addr, fn->fn_bit);
 806                 pn = fn;
 807                 fn = dir ?
 808                      rcu_dereference_protected(fn->right,
 809                                         lockdep_is_held(&table->tb6_lock)) :
 810                      rcu_dereference_protected(fn->left,
 811                                         lockdep_is_held(&table->tb6_lock));
 812         } while (fn);
 813
 814         if (!allow_create) {
 815                 /* We should not create new node because
 816                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 817                  * I assume it is safe to require NLM_F_CREATE when
 818                  * REPLACE flag is used! Later we may want to remove the
 819                  * check for replace_required, because according
 820                  * to netlink specification, NLM_F_CREATE
 821                  * MUST be specified if new route is created.
 822                  * That would keep IPv6 consistent with IPv4
 823                  */
 824                 if (replace_required) {
 825                         NL_SET_ERR_MSG(extack,
 826                                        "Can not replace route - no match found");
 827                         pr_warn("Can't replace route, no match found\n");
 828                         return ERR_PTR(-ENOENT);
 829                 }
 830                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 831         }
 832         /*
 833          *      We walked to the bottom of tree.
 834          *      Create new leaf node without children.
 835          */
 836
 837         ln = node_alloc(net);
 838
 839         if (!ln)
 840                 return ERR_PTR(-ENOMEM);
 841         ln->fn_bit = plen;
 842         RCU_INIT_POINTER(ln->parent, pn);
 843
 844         if (dir)
 845                 rcu_assign_pointer(pn->right, ln);
 846         else
 847                 rcu_assign_pointer(pn->left, ln);
 848
 849         return ln;
 850
 851
 852 insert_above:
 853         /*
 854          * split since we don't have a common prefix anymore or
 855          * we have a less significant route.
 856          * we've to insert an intermediate node on the list
 857          * this new node will point to the one we need to create
 858          * and the current
 859          */
 860
 861         pn = rcu_dereference_protected(fn->parent,
 862                                        lockdep_is_held(&table->tb6_lock));
 863
 864         /* find 1st bit in difference between the 2 addrs.
 865
 866            See comment in __ipv6_addr_diff: bit may be an invalid value,
 867            but if it is >= plen, the value is ignored in any case.
 868          */
 869
 870         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 871
 872         /*
 873          *              (intermediate)[in]
 874          *                /        \
 875          *      (new leaf node)[ln] (old node)[fn]
 876          */
 877         if (plen > bit) {
 878                 in = node_alloc(net);
 879                 ln = node_alloc(net);
 880
 881                 if (!in || !ln) {
 882                         if (in)
 883                                 node_free_immediate(net, in);
 884                         if (ln)
 885                                 node_free_immediate(net, ln);
 886                         return ERR_PTR(-ENOMEM);
 887                 }
 888
 889                 /*
 890                  * new intermediate node.
 891                  * RTN_RTINFO will
 892                  * be off since that an address that chooses one of
 893                  * the branches would not match less specific routes
 894                  * in the other branch
 895                  */
 896
 897                 in->fn_bit = bit;
 898
 899                 RCU_INIT_POINTER(in->parent, pn);
 900                 in->leaf = fn->leaf;
 901                 fib6_info_hold(rcu_dereference_protected(in->leaf,
 902                                 lockdep_is_held(&table->tb6_lock)));
 903
 904                 /* update parent pointer */
 905                 if (dir)
 906                         rcu_assign_pointer(pn->right, in);
 907                 else
 908                         rcu_assign_pointer(pn->left, in);
 909
 910                 ln->fn_bit = plen;
 911
 912                 RCU_INIT_POINTER(ln->parent, in);
 913                 rcu_assign_pointer(fn->parent, in);
 914
 915                 if (addr_bit_set(addr, bit)) {
 916                         rcu_assign_pointer(in->right, ln);
 917                         rcu_assign_pointer(in->left, fn);
 918                 } else {
 919                         rcu_assign_pointer(in->left, ln);
 920                         rcu_assign_pointer(in->right, fn);
 921                 }
 922         } else { /* plen <= bit */
 923
 924                 /*
 925                  *              (new leaf node)[ln]
 926                  *                /        \
 927                  *           (old node)[fn] NULL
 928                  */
 929
 930                 ln = node_alloc(net);
 931
 932                 if (!ln)
 933                         return ERR_PTR(-ENOMEM);
 934
 935                 ln->fn_bit = plen;
 936
 937                 RCU_INIT_POINTER(ln->parent, pn);
 938
 939                 if (addr_bit_set(&key->addr, plen))
 940                         RCU_INIT_POINTER(ln->right, fn);
 941                 else
 942                         RCU_INIT_POINTER(ln->left, fn);
 943
 944                 rcu_assign_pointer(fn->parent, ln);
 945
 946                 if (dir)
 947                         rcu_assign_pointer(pn->right, ln);
 948                 else
 949                         rcu_assign_pointer(pn->left, ln);
 950         }
 951         return ln;
 952 }
 953
 954 static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh,
 955                                   const struct fib6_info *match,
 956                                   const struct fib6_table *table)
 957 {
 958         int cpu;
 959
 960         if (!fib6_nh->rt6i_pcpu)
 961                 return;
 962
 963         /* release the reference to this fib entry from
 964          * all of its cached pcpu routes
 965          */
 966         for_each_possible_cpu(cpu) {
 967                 struct rt6_info **ppcpu_rt;
 968                 struct rt6_info *pcpu_rt;
 969
 970                 ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
 971                 pcpu_rt = *ppcpu_rt;
 972
 973                 /* only dropping the 'from' reference if the cached route
 974                  * is using 'match'. The cached pcpu_rt->from only changes
 975                  * from a fib6_info to NULL (ip6_dst_destroy); it can never
 976                  * change from one fib6_info reference to another
 977                  */
 978                 if (pcpu_rt && rcu_access_pointer(pcpu_rt->from) == match) {
 979                         struct fib6_info *from;
 980
 981                         from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
 982                         fib6_info_release(from);
 983                 }
 984         }
 985 }
 986
 987 struct fib6_nh_pcpu_arg {
 988         struct fib6_info        *from;
 989         const struct fib6_table *table;
 990 };
 991
 992 static int fib6_nh_drop_pcpu_from(struct fib6_nh *nh, void *_arg)
 993 {
 994         struct fib6_nh_pcpu_arg *arg = _arg;
 995
 996         __fib6_drop_pcpu_from(nh, arg->from, arg->table);
 997         return 0;
 998 }
 999
1000 static void fib6_drop_pcpu_from(struct fib6_info *f6i,
1001                                 const struct fib6_table *table)
1002 {
1003         /* Make sure rt6_make_pcpu_route() wont add other percpu routes
1004          * while we are cleaning them here.
1005          */
1006         f6i->fib6_destroying = 1;
1007         mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
1008
1009         if (f6i->nh) {
1010                 struct fib6_nh_pcpu_arg arg = {
1011                         .from = f6i,
1012                         .table = table
1013                 };
1014
1015                 nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_drop_pcpu_from,
1016                                          &arg);
1017         } else {
1018                 struct fib6_nh *fib6_nh;
1019
1020                 fib6_nh = f6i->fib6_nh;
1021                 __fib6_drop_pcpu_from(fib6_nh, f6i, table);
1022         }
1023 }
1024
1025 static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn,
1026                           struct net *net)
1027 {
1028         struct fib6_table *table = rt->fib6_table;
1029
1030         /* Flush all cached dst in exception table */
1031         rt6_flush_exceptions(rt);
1032         fib6_drop_pcpu_from(rt, table);
1033
1034         if (rt->nh && !list_empty(&rt->nh_list))
1035                 list_del_init(&rt->nh_list);
1036
1037         if (refcount_read(&rt->fib6_ref) != 1) {
1038                 /* This route is used as dummy address holder in some split
1039                  * nodes. It is not leaked, but it still holds other resources,
1040                  * which must be released in time. So, scan ascendant nodes
1041                  * and replace dummy references to this route with references
1042                  * to still alive ones.
1043                  */
1044                 while (fn) {
1045                         struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
1046                                             lockdep_is_held(&table->tb6_lock));
1047                         struct fib6_info *new_leaf;
1048                         if (!(fn->fn_flags & RTN_RTINFO) && leaf == rt) {
1049                                 new_leaf = fib6_find_prefix(net, table, fn);
1050                                 fib6_info_hold(new_leaf);
1051
1052                                 rcu_assign_pointer(fn->leaf, new_leaf);
1053                                 fib6_info_release(rt);
1054                         }
1055                         fn = rcu_dereference_protected(fn->parent,
1056                                     lockdep_is_held(&table->tb6_lock));
1057                 }
1058         }
1059 }
1060
1061 /*
1062  *      Insert routing information in a node.
1063  */
1064
1065 static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
1066                             struct nl_info *info,
1067                             struct netlink_ext_ack *extack)
1068 {
1069         struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
1070                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1071         struct fib6_info *iter = NULL;
1072         struct fib6_info __rcu **ins;
1073         struct fib6_info __rcu **fallback_ins = NULL;
1074         int replace = (info->nlh &&
1075                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
1076         int add = (!info->nlh ||
1077                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
1078         int found = 0;
1079         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
1080         bool notify_sibling_rt = false;
1081         u16 nlflags = NLM_F_EXCL;
1082         int err;
1083
1084         if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))
1085                 nlflags |= NLM_F_APPEND;
1086
1087         ins = &fn->leaf;
1088
1089         for (iter = leaf; iter;
1090              iter = rcu_dereference_protected(iter->fib6_next,
1091                                 lockdep_is_held(&rt->fib6_table->tb6_lock))) {
1092                 /*
1093                  *      Search for duplicates
1094                  */
1095
1096                 if (iter->fib6_metric == rt->fib6_metric) {
1097                         /*
1098                          *      Same priority level
1099                          */
1100                         if (info->nlh &&
1101                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
1102                                 return -EEXIST;
1103
1104                         nlflags &= ~NLM_F_EXCL;
1105                         if (replace) {
1106                                 if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
1107                                         found++;
1108                                         break;
1109                                 }
1110                                 fallback_ins = fallback_ins ?: ins;
1111                                 goto next_iter;
1112                         }
1113
1114                         if (rt6_duplicate_nexthop(iter, rt)) {
1115                                 if (rt->fib6_nsiblings)
1116                                         rt->fib6_nsiblings = 0;
1117                                 if (!(iter->fib6_flags & RTF_EXPIRES))
1118                                         return -EEXIST;
1119                                 if (!(rt->fib6_flags & RTF_EXPIRES))
1120                                         fib6_clean_expires(iter);
1121                                 else
1122                                         fib6_set_expires(iter, rt->expires);
1123
1124                                 if (rt->fib6_pmtu)
1125                                         fib6_metric_set(iter, RTAX_MTU,
1126                                                         rt->fib6_pmtu);
1127                                 return -EEXIST;
1128                         }
1129                         /* If we have the same destination and the same metric,
1130                          * but not the same gateway, then the route we try to
1131                          * add is sibling to this route, increment our counter
1132                          * of siblings, and later we will add our route to the
1133                          * list.
1134                          * Only static routes (which don't have flag
1135                          * RTF_EXPIRES) are used for ECMPv6.
1136                          *
1137                          * To avoid long list, we only had siblings if the
1138                          * route have a gateway.
1139                          */
1140                         if (rt_can_ecmp &&
1141                             rt6_qualify_for_ecmp(iter))
1142                                 rt->fib6_nsiblings++;
1143                 }
1144
1145                 if (iter->fib6_metric > rt->fib6_metric)
1146                         break;
1147
1148 next_iter:
1149                 ins = &iter->fib6_next;
1150         }
1151
1152         if (fallback_ins && !found) {
1153                 /* No matching route with same ecmp-able-ness found, replace
1154                  * first matching route
1155                  */
1156                 ins = fallback_ins;
1157                 iter = rcu_dereference_protected(*ins,
1158                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1159                 found++;
1160         }
1161
1162         /* Reset round-robin state, if necessary */
1163         if (ins == &fn->leaf)
1164                 fn->rr_ptr = NULL;
1165
1166         /* Link this route to others same route. */
1167         if (rt->fib6_nsiblings) {
1168                 unsigned int fib6_nsiblings;
1169                 struct fib6_info *sibling, *temp_sibling;
1170
1171                 /* Find the first route that have the same metric */
1172                 sibling = leaf;
1173                 notify_sibling_rt = true;
1174                 while (sibling) {
1175                         if (sibling->fib6_metric == rt->fib6_metric &&
1176                             rt6_qualify_for_ecmp(sibling)) {
1177                                 list_add_tail(&rt->fib6_siblings,
1178                                               &sibling->fib6_siblings);
1179                                 break;
1180                         }
1181                         sibling = rcu_dereference_protected(sibling->fib6_next,
1182                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1183                         notify_sibling_rt = false;
1184                 }
1185                 /* For each sibling in the list, increment the counter of
1186                  * siblings. BUG() if counters does not match, list of siblings
1187                  * is broken!
1188                  */
1189                 fib6_nsiblings = 0;
1190                 list_for_each_entry_safe(sibling, temp_sibling,
1191                                          &rt->fib6_siblings, fib6_siblings) {
1192                         sibling->fib6_nsiblings++;
1193                         BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings);
1194                         fib6_nsiblings++;
1195                 }
1196                 BUG_ON(fib6_nsiblings != rt->fib6_nsiblings);
1197                 rt6_multipath_rebalance(temp_sibling);
1198         }
1199
1200         /*
1201          *      insert node
1202          */
1203         if (!replace) {
1204                 if (!add)
1205                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
1206
1207 add:
1208                 nlflags |= NLM_F_CREATE;
1209
1210                 /* The route should only be notified if it is the first
1211                  * route in the node or if it is added as a sibling
1212                  * route to the first route in the node.
1213                  */
1214                 if (!info->skip_notify_kernel &&
1215                     (notify_sibling_rt || ins == &fn->leaf)) {
1216                         enum fib_event_type fib_event;
1217
1218                         if (notify_sibling_rt)
1219                                 fib_event = FIB_EVENT_ENTRY_APPEND;
1220                         else
1221                                 fib_event = FIB_EVENT_ENTRY_REPLACE;
1222                         err = call_fib6_entry_notifiers(info->nl_net,
1223                                                         fib_event, rt,
1224                                                         extack);
1225                         if (err) {
1226                                 struct fib6_info *sibling, *next_sibling;
1227
1228                                 /* If the route has siblings, then it first
1229                                  * needs to be unlinked from them.
1230                                  */
1231                                 if (!rt->fib6_nsiblings)
1232                                         return err;
1233
1234                                 list_for_each_entry_safe(sibling, next_sibling,
1235                                                          &rt->fib6_siblings,
1236                                                          fib6_siblings)
1237                                         sibling->fib6_nsiblings--;
1238                                 rt->fib6_nsiblings = 0;
1239                                 list_del_init(&rt->fib6_siblings);
1240                                 rt6_multipath_rebalance(next_sibling);
1241                                 return err;
1242                         }
1243                 }
1244
1245                 rcu_assign_pointer(rt->fib6_next, iter);
1246                 fib6_info_hold(rt);
1247                 rcu_assign_pointer(rt->fib6_node, fn);
1248                 rcu_assign_pointer(*ins, rt);
1249                 if (!info->skip_notify)
1250                         inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
1251                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
1252
1253                 if (!(fn->fn_flags & RTN_RTINFO)) {
1254                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1255                         fn->fn_flags |= RTN_RTINFO;
1256                 }
1257
1258         } else {
1259                 int nsiblings;
1260
1261                 if (!found) {
1262                         if (add)
1263                                 goto add;
1264                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
1265                         return -ENOENT;
1266                 }
1267
1268                 if (!info->skip_notify_kernel && ins == &fn->leaf) {
1269                         err = call_fib6_entry_notifiers(info->nl_net,
1270                                                         FIB_EVENT_ENTRY_REPLACE,
1271                                                         rt, extack);
1272                         if (err)
1273                                 return err;
1274                 }
1275
1276                 fib6_info_hold(rt);
1277                 rcu_assign_pointer(rt->fib6_node, fn);
1278                 rt->fib6_next = iter->fib6_next;
1279                 rcu_assign_pointer(*ins, rt);
1280                 if (!info->skip_notify)
1281                         inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
1282                 if (!(fn->fn_flags & RTN_RTINFO)) {
1283                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1284                         fn->fn_flags |= RTN_RTINFO;
1285                 }
1286                 nsiblings = iter->fib6_nsiblings;
1287                 iter->fib6_node = NULL;
1288                 fib6_purge_rt(iter, fn, info->nl_net);
1289                 if (rcu_access_pointer(fn->rr_ptr) == iter)
1290                         fn->rr_ptr = NULL;
1291                 fib6_info_release(iter);
1292
1293                 if (nsiblings) {
1294                         /* Replacing an ECMP route, remove all siblings */
1295                         ins = &rt->fib6_next;
1296                         iter = rcu_dereference_protected(*ins,
1297                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1298                         while (iter) {
1299                                 if (iter->fib6_metric > rt->fib6_metric)
1300                                         break;
1301                                 if (rt6_qualify_for_ecmp(iter)) {
1302                                         *ins = iter->fib6_next;
1303                                         iter->fib6_node = NULL;
1304                                         fib6_purge_rt(iter, fn, info->nl_net);
1305                                         if (rcu_access_pointer(fn->rr_ptr) == iter)
1306                                                 fn->rr_ptr = NULL;
1307                                         fib6_info_release(iter);
1308                                         nsiblings--;
1309                                         info->nl_net->ipv6.rt6_stats->fib_rt_entries--;
1310                                 } else {
1311                                         ins = &iter->fib6_next;
1312                                 }
1313                                 iter = rcu_dereference_protected(*ins,
1314                                         lockdep_is_held(&rt->fib6_table->tb6_lock));
1315                         }
1316                         WARN_ON(nsiblings != 0);
1317                 }
1318         }
1319
1320         return 0;
1321 }
1322
1323 static void fib6_start_gc(struct net *net, struct fib6_info *rt)
1324 {
1325         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
1326             (rt->fib6_flags & RTF_EXPIRES))
1327                 mod_timer(&net->ipv6.ip6_fib_timer,
1328                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1329 }
1330
1331 void fib6_force_start_gc(struct net *net)
1332 {
1333         if (!timer_pending(&net->ipv6.ip6_fib_timer))
1334                 mod_timer(&net->ipv6.ip6_fib_timer,
1335                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1336 }
1337
1338 static void __fib6_update_sernum_upto_root(struct fib6_info *rt,
1339                                            int sernum)
1340 {
1341         struct fib6_node *fn = rcu_dereference_protected(rt->fib6_node,
1342                                 lockdep_is_held(&rt->fib6_table->tb6_lock));
1343
1344         /* paired with smp_rmb() in rt6_get_cookie_safe() */
1345         smp_wmb();
1346         while (fn) {
1347                 fn->fn_sernum = sernum;
1348                 fn = rcu_dereference_protected(fn->parent,
1349                                 lockdep_is_held(&rt->fib6_table->tb6_lock));
1350         }
1351 }
1352
1353 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt)
1354 {
1355         __fib6_update_sernum_upto_root(rt, fib6_new_sernum(net));
1356 }
1357
1358 /* allow ipv4 to update sernum via ipv6_stub */
1359 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i)
1360 {
1361         spin_lock_bh(&f6i->fib6_table->tb6_lock);
1362         fib6_update_sernum_upto_root(net, f6i);
1363         spin_unlock_bh(&f6i->fib6_table->tb6_lock);
1364 }
1365
1366 /*
1367  *      Add routing information to the routing tree.
1368  *      <destination addr>/<source addr>
1369  *      with source addr info in sub-trees
1370  *      Need to own table->tb6_lock
1371  */
1372
1373 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
1374              struct nl_info *info, struct netlink_ext_ack *extack)
1375 {
1376         struct fib6_table *table = rt->fib6_table;
1377         struct fib6_node *fn, *pn = NULL;
1378         int err = -ENOMEM;
1379         int allow_create = 1;
1380         int replace_required = 0;
1381         int sernum = fib6_new_sernum(info->nl_net);
1382
1383         if (info->nlh) {
1384                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
1385                         allow_create = 0;
1386                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
1387                         replace_required = 1;
1388         }
1389         if (!allow_create && !replace_required)
1390                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
1391
1392         fn = fib6_add_1(info->nl_net, table, root,
1393                         &rt->fib6_dst.addr, rt->fib6_dst.plen,
1394                         offsetof(struct fib6_info, fib6_dst), allow_create,
1395                         replace_required, extack);
1396         if (IS_ERR(fn)) {
1397                 err = PTR_ERR(fn);
1398                 fn = NULL;
1399                 goto out;
1400         }
1401
1402         pn = fn;
1403
1404 #ifdef CONFIG_IPV6_SUBTREES
1405         if (rt->fib6_src.plen) {
1406                 struct fib6_node *sn;
1407
1408                 if (!rcu_access_pointer(fn->subtree)) {
1409                         struct fib6_node *sfn;
1410
1411                         /*
1412                          * Create subtree.
1413                          *
1414                          *              fn[main tree]
1415                          *              |
1416                          *              sfn[subtree root]
1417                          *                 \
1418                          *                  sn[new leaf node]
1419                          */
1420
1421                         /* Create subtree root node */
1422                         sfn = node_alloc(info->nl_net);
1423                         if (!sfn)
1424                                 goto failure;
1425
1426                         fib6_info_hold(info->nl_net->ipv6.fib6_null_entry);
1427                         rcu_assign_pointer(sfn->leaf,
1428                                            info->nl_net->ipv6.fib6_null_entry);
1429                         sfn->fn_flags = RTN_ROOT;
1430
1431                         /* Now add the first leaf node to new subtree */
1432
1433                         sn = fib6_add_1(info->nl_net, table, sfn,
1434                                         &rt->fib6_src.addr, rt->fib6_src.plen,
1435                                         offsetof(struct fib6_info, fib6_src),
1436                                         allow_create, replace_required, extack);
1437
1438                         if (IS_ERR(sn)) {
1439                                 /* If it is failed, discard just allocated
1440                                    root, and then (in failure) stale node
1441                                    in main tree.
1442                                  */
1443                                 node_free_immediate(info->nl_net, sfn);
1444                                 err = PTR_ERR(sn);
1445                                 goto failure;
1446                         }
1447
1448                         /* Now link new subtree to main tree */
1449                         rcu_assign_pointer(sfn->parent, fn);
1450                         rcu_assign_pointer(fn->subtree, sfn);
1451                 } else {
1452                         sn = fib6_add_1(info->nl_net, table, FIB6_SUBTREE(fn),
1453                                         &rt->fib6_src.addr, rt->fib6_src.plen,
1454                                         offsetof(struct fib6_info, fib6_src),
1455                                         allow_create, replace_required, extack);
1456
1457                         if (IS_ERR(sn)) {
1458                                 err = PTR_ERR(sn);
1459                                 goto failure;
1460                         }
1461                 }
1462
1463                 if (!rcu_access_pointer(fn->leaf)) {
1464                         if (fn->fn_flags & RTN_TL_ROOT) {
1465                                 /* put back null_entry for root node */
1466                                 rcu_assign_pointer(fn->leaf,
1467                                             info->nl_net->ipv6.fib6_null_entry);
1468                         } else {
1469                                 fib6_info_hold(rt);
1470                                 rcu_assign_pointer(fn->leaf, rt);
1471                         }
1472                 }
1473                 fn = sn;
1474         }
1475 #endif
1476
1477         err = fib6_add_rt2node(fn, rt, info, extack);
1478         if (!err) {
1479                 if (rt->nh)
1480                         list_add(&rt->nh_list, &rt->nh->f6i_list);
1481                 __fib6_update_sernum_upto_root(rt, sernum);
1482                 fib6_start_gc(info->nl_net, rt);
1483         }
1484
1485 out:
1486         if (err) {
1487 #ifdef CONFIG_IPV6_SUBTREES
1488                 /*
1489                  * If fib6_add_1 has cleared the old leaf pointer in the
1490                  * super-tree leaf node we have to find a new one for it.
1491                  */
1492                 if (pn != fn) {
1493                         struct fib6_info *pn_leaf =
1494                                 rcu_dereference_protected(pn->leaf,
1495                                     lockdep_is_held(&table->tb6_lock));
1496                         if (pn_leaf == rt) {
1497                                 pn_leaf = NULL;
1498                                 RCU_INIT_POINTER(pn->leaf, NULL);
1499                                 fib6_info_release(rt);
1500                         }
1501                         if (!pn_leaf && !(pn->fn_flags & RTN_RTINFO)) {
1502                                 pn_leaf = fib6_find_prefix(info->nl_net, table,
1503                                                            pn);
1504 #if RT6_DEBUG >= 2
1505                                 if (!pn_leaf) {
1506                                         WARN_ON(!pn_leaf);
1507                                         pn_leaf =
1508                                             info->nl_net->ipv6.fib6_null_entry;
1509                                 }
1510 #endif
1511                                 fib6_info_hold(pn_leaf);
1512                                 rcu_assign_pointer(pn->leaf, pn_leaf);
1513                         }
1514                 }
1515 #endif
1516                 goto failure;
1517         } else if (fib6_requires_src(rt)) {
1518                 fib6_routes_require_src_inc(info->nl_net);
1519         }
1520         return err;
1521
1522 failure:
1523         /* fn->leaf could be NULL and fib6_repair_tree() needs to be called if:
1524          * 1. fn is an intermediate node and we failed to add the new
1525          * route to it in both subtree creation failure and fib6_add_rt2node()
1526          * failure case.
1527          * 2. fn is the root node in the table and we fail to add the first
1528          * default route to it.
1529          */
1530         if (fn &&
1531             (!(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)) ||
1532              (fn->fn_flags & RTN_TL_ROOT &&
1533               !rcu_access_pointer(fn->leaf))))
1534                 fib6_repair_tree(info->nl_net, table, fn);
1535         return err;
1536 }
1537
1538 /*
1539  *      Routing tree lookup
1540  *
1541  */
1542
1543 struct lookup_args {
1544         int                     offset;         /* key offset on fib6_info */
1545         const struct in6_addr   *addr;          /* search key                   */
1546 };
1547
1548 static struct fib6_node *fib6_node_lookup_1(struct fib6_node *root,
1549                                             struct lookup_args *args)
1550 {
1551         struct fib6_node *fn;
1552         __be32 dir;
1553
1554         if (unlikely(args->offset == 0))
1555                 return NULL;
1556
1557         /*
1558          *      Descend on a tree
1559          */
1560
1561         fn = root;
1562
1563         for (;;) {
1564                 struct fib6_node *next;
1565
1566                 dir = addr_bit_set(args->addr, fn->fn_bit);
1567
1568                 next = dir ? rcu_dereference(fn->right) :
1569                              rcu_dereference(fn->left);
1570
1571                 if (next) {
1572                         fn = next;
1573                         continue;
1574                 }
1575                 break;
1576         }
1577
1578         while (fn) {
1579                 struct fib6_node *subtree = FIB6_SUBTREE(fn);
1580
1581                 if (subtree || fn->fn_flags & RTN_RTINFO) {
1582                         struct fib6_info *leaf = rcu_dereference(fn->leaf);
1583                         struct rt6key *key;
1584
1585                         if (!leaf)
1586                                 goto backtrack;
1587
1588                         key = (struct rt6key *) ((u8 *)leaf + args->offset);
1589
1590                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1591 #ifdef CONFIG_IPV6_SUBTREES
1592                                 if (subtree) {
1593                                         struct fib6_node *sfn;
1594                                         sfn = fib6_node_lookup_1(subtree,
1595                                                                  args + 1);
1596                                         if (!sfn)
1597                                                 goto backtrack;
1598                                         fn = sfn;
1599                                 }
1600 #endif
1601                                 if (fn->fn_flags & RTN_RTINFO)
1602                                         return fn;
1603                         }
1604                 }
1605 backtrack:
1606                 if (fn->fn_flags & RTN_ROOT)
1607                         break;
1608
1609                 fn = rcu_dereference(fn->parent);
1610         }
1611
1612         return NULL;
1613 }
1614
1615 /* called with rcu_read_lock() held
1616  */
1617 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
1618                                    const struct in6_addr *daddr,
1619                                    const struct in6_addr *saddr)
1620 {
1621         struct fib6_node *fn;
1622         struct lookup_args args[] = {
1623                 {
1624                         .offset = offsetof(struct fib6_info, fib6_dst),
1625                         .addr = daddr,
1626                 },
1627 #ifdef CONFIG_IPV6_SUBTREES
1628                 {
1629                         .offset = offsetof(struct fib6_info, fib6_src),
1630                         .addr = saddr,
1631                 },
1632 #endif
1633                 {
1634                         .offset = 0,    /* sentinel */
1635                 }
1636         };
1637
1638         fn = fib6_node_lookup_1(root, daddr ? args : args + 1);
1639         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1640                 fn = root;
1641
1642         return fn;
1643 }
1644
1645 /*
1646  *      Get node with specified destination prefix (and source prefix,
1647  *      if subtrees are used)
1648  *      exact_match == true means we try to find fn with exact match of
1649  *      the passed in prefix addr
1650  *      exact_match == false means we try to find fn with longest prefix
1651  *      match of the passed in prefix addr. This is useful for finding fn
1652  *      for cached route as it will be stored in the exception table under
1653  *      the node with longest prefix length.
1654  */
1655
1656
1657 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1658                                        const struct in6_addr *addr,
1659                                        int plen, int offset,
1660                                        bool exact_match)
1661 {
1662         struct fib6_node *fn, *prev = NULL;
1663
1664         for (fn = root; fn ; ) {
1665                 struct fib6_info *leaf = rcu_dereference(fn->leaf);
1666                 struct rt6key *key;
1667
1668                 /* This node is being deleted */
1669                 if (!leaf) {
1670                         if (plen <= fn->fn_bit)
1671                                 goto out;
1672                         else
1673                                 goto next;
1674                 }
1675
1676                 key = (struct rt6key *)((u8 *)leaf + offset);
1677
1678                 /*
1679                  *      Prefix match
1680                  */
1681                 if (plen < fn->fn_bit ||
1682                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1683                         goto out;
1684
1685                 if (plen == fn->fn_bit)
1686                         return fn;
1687
1688                 if (fn->fn_flags & RTN_RTINFO)
1689                         prev = fn;
1690
1691 next:
1692                 /*
1693                  *      We have more bits to go
1694                  */
1695                 if (addr_bit_set(addr, fn->fn_bit))
1696                         fn = rcu_dereference(fn->right);
1697                 else
1698                         fn = rcu_dereference(fn->left);
1699         }
1700 out:
1701         if (exact_match)
1702                 return NULL;
1703         else
1704                 return prev;
1705 }
1706
1707 struct fib6_node *fib6_locate(struct fib6_node *root,
1708                               const struct in6_addr *daddr, int dst_len,
1709                               const struct in6_addr *saddr, int src_len,
1710                               bool exact_match)
1711 {
1712         struct fib6_node *fn;
1713
1714         fn = fib6_locate_1(root, daddr, dst_len,
1715                            offsetof(struct fib6_info, fib6_dst),
1716                            exact_match);
1717
1718 #ifdef CONFIG_IPV6_SUBTREES
1719         if (src_len) {
1720                 WARN_ON(saddr == NULL);
1721                 if (fn) {
1722                         struct fib6_node *subtree = FIB6_SUBTREE(fn);
1723
1724                         if (subtree) {
1725                                 fn = fib6_locate_1(subtree, saddr, src_len,
1726                                            offsetof(struct fib6_info, fib6_src),
1727                                            exact_match);
1728                         }
1729                 }
1730         }
1731 #endif
1732
1733         if (fn && fn->fn_flags & RTN_RTINFO)
1734                 return fn;
1735
1736         return NULL;
1737 }
1738
1739
1740 /*
1741  *      Deletion
1742  *
1743  */
1744
1745 static struct fib6_info *fib6_find_prefix(struct net *net,
1746                                          struct fib6_table *table,
1747                                          struct fib6_node *fn)
1748 {
1749         struct fib6_node *child_left, *child_right;
1750
1751         if (fn->fn_flags & RTN_ROOT)
1752                 return net->ipv6.fib6_null_entry;
1753
1754         while (fn) {
1755                 child_left = rcu_dereference_protected(fn->left,
1756                                     lockdep_is_held(&table->tb6_lock));
1757                 child_right = rcu_dereference_protected(fn->right,
1758                                     lockdep_is_held(&table->tb6_lock));
1759                 if (child_left)
1760                         return rcu_dereference_protected(child_left->leaf,
1761                                         lockdep_is_held(&table->tb6_lock));
1762                 if (child_right)
1763                         return rcu_dereference_protected(child_right->leaf,
1764                                         lockdep_is_held(&table->tb6_lock));
1765
1766                 fn = FIB6_SUBTREE(fn);
1767         }
1768         return NULL;
1769 }
1770
1771 /*
1772  *      Called to trim the tree of intermediate nodes when possible. "fn"
1773  *      is the node we want to try and remove.
1774  *      Need to own table->tb6_lock
1775  */
1776
1777 static struct fib6_node *fib6_repair_tree(struct net *net,
1778                                           struct fib6_table *table,
1779                                           struct fib6_node *fn)
1780 {
1781         int children;
1782         int nstate;
1783         struct fib6_node *child;
1784         struct fib6_walker *w;
1785         int iter = 0;
1786
1787         /* Set fn->leaf to null_entry for root node. */
1788         if (fn->fn_flags & RTN_TL_ROOT) {
1789                 rcu_assign_pointer(fn->leaf, net->ipv6.fib6_null_entry);
1790                 return fn;
1791         }
1792
1793         for (;;) {
1794                 struct fib6_node *fn_r = rcu_dereference_protected(fn->right,
1795                                             lockdep_is_held(&table->tb6_lock));
1796                 struct fib6_node *fn_l = rcu_dereference_protected(fn->left,
1797                                             lockdep_is_held(&table->tb6_lock));
1798                 struct fib6_node *pn = rcu_dereference_protected(fn->parent,
1799                                             lockdep_is_held(&table->tb6_lock));
1800                 struct fib6_node *pn_r = rcu_dereference_protected(pn->right,
1801                                             lockdep_is_held(&table->tb6_lock));
1802                 struct fib6_node *pn_l = rcu_dereference_protected(pn->left,
1803                                             lockdep_is_held(&table->tb6_lock));
1804                 struct fib6_info *fn_leaf = rcu_dereference_protected(fn->leaf,
1805                                             lockdep_is_held(&table->tb6_lock));
1806                 struct fib6_info *pn_leaf = rcu_dereference_protected(pn->leaf,
1807                                             lockdep_is_held(&table->tb6_lock));
1808                 struct fib6_info *new_fn_leaf;
1809
1810                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1811                 iter++;
1812
1813                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1814                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1815                 WARN_ON(fn_leaf);
1816
1817                 children = 0;
1818                 child = NULL;
1819                 if (fn_r) {
1820                         child = fn_r;
1821                         children |= 1;
1822                 }
1823                 if (fn_l) {
1824                         child = fn_l;
1825                         children |= 2;
1826                 }
1827
1828                 if (children == 3 || FIB6_SUBTREE(fn)
1829 #ifdef CONFIG_IPV6_SUBTREES
1830                     /* Subtree root (i.e. fn) may have one child */
1831                     || (children && fn->fn_flags & RTN_ROOT)
1832 #endif
1833                     ) {
1834                         new_fn_leaf = fib6_find_prefix(net, table, fn);
1835 #if RT6_DEBUG >= 2
1836                         if (!new_fn_leaf) {
1837                                 WARN_ON(!new_fn_leaf);
1838                                 new_fn_leaf = net->ipv6.fib6_null_entry;
1839                         }
1840 #endif
1841                         fib6_info_hold(new_fn_leaf);
1842                         rcu_assign_pointer(fn->leaf, new_fn_leaf);
1843                         return pn;
1844                 }
1845
1846 #ifdef CONFIG_IPV6_SUBTREES
1847                 if (FIB6_SUBTREE(pn) == fn) {
1848                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1849                         RCU_INIT_POINTER(pn->subtree, NULL);
1850                         nstate = FWS_L;
1851                 } else {
1852                         WARN_ON(fn->fn_flags & RTN_ROOT);
1853 #endif
1854                         if (pn_r == fn)
1855                                 rcu_assign_pointer(pn->right, child);
1856                         else if (pn_l == fn)
1857                                 rcu_assign_pointer(pn->left, child);
1858 #if RT6_DEBUG >= 2
1859                         else
1860                                 WARN_ON(1);
1861 #endif
1862                         if (child)
1863                                 rcu_assign_pointer(child->parent, pn);
1864                         nstate = FWS_R;
1865 #ifdef CONFIG_IPV6_SUBTREES
1866                 }
1867 #endif
1868
1869                 read_lock(&net->ipv6.fib6_walker_lock);
1870                 FOR_WALKERS(net, w) {
1871                         if (!child) {
1872                                 if (w->node == fn) {
1873                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1874                                         w->node = pn;
1875                                         w->state = nstate;
1876                                 }
1877                         } else {
1878                                 if (w->node == fn) {
1879                                         w->node = child;
1880                                         if (children&2) {
1881                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1882                                                 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1883                                         } else {
1884                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1885                                                 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1886                                         }
1887                                 }
1888                         }
1889                 }
1890                 read_unlock(&net->ipv6.fib6_walker_lock);
1891
1892                 node_free(net, fn);
1893                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1894                         return pn;
1895
1896                 RCU_INIT_POINTER(pn->leaf, NULL);
1897                 fib6_info_release(pn_leaf);
1898                 fn = pn;
1899         }
1900 }
1901
1902 static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
1903                            struct fib6_info __rcu **rtp, struct nl_info *info)
1904 {
1905         struct fib6_info *leaf, *replace_rt = NULL;
1906         struct fib6_walker *w;
1907         struct fib6_info *rt = rcu_dereference_protected(*rtp,
1908                                     lockdep_is_held(&table->tb6_lock));
1909         struct net *net = info->nl_net;
1910         bool notify_del = false;
1911
1912         RT6_TRACE("fib6_del_route\n");
1913
1914         /* If the deleted route is the first in the node and it is not part of
1915          * a multipath route, then we need to replace it with the next route
1916          * in the node, if exists.
1917          */
1918         leaf = rcu_dereference_protected(fn->leaf,
1919                                          lockdep_is_held(&table->tb6_lock));
1920         if (leaf == rt && !rt->fib6_nsiblings) {
1921                 if (rcu_access_pointer(rt->fib6_next))
1922                         replace_rt = rcu_dereference_protected(rt->fib6_next,
1923                                             lockdep_is_held(&table->tb6_lock));
1924                 else
1925                         notify_del = true;
1926         }
1927
1928         /* Unlink it */
1929         *rtp = rt->fib6_next;
1930         rt->fib6_node = NULL;
1931         net->ipv6.rt6_stats->fib_rt_entries--;
1932         net->ipv6.rt6_stats->fib_discarded_routes++;
1933
1934         /* Reset round-robin state, if necessary */
1935         if (rcu_access_pointer(fn->rr_ptr) == rt)
1936                 fn->rr_ptr = NULL;
1937
1938         /* Remove this entry from other siblings */
1939         if (rt->fib6_nsiblings) {
1940                 struct fib6_info *sibling, *next_sibling;
1941
1942                 /* The route is deleted from a multipath route. If this
1943                  * multipath route is the first route in the node, then we need
1944                  * to emit a delete notification. Otherwise, we need to skip
1945                  * the notification.
1946                  */
1947                 if (rt->fib6_metric == leaf->fib6_metric &&
1948                     rt6_qualify_for_ecmp(leaf))
1949                         notify_del = true;
1950                 list_for_each_entry_safe(sibling, next_sibling,
1951                                          &rt->fib6_siblings, fib6_siblings)
1952                         sibling->fib6_nsiblings--;
1953                 rt->fib6_nsiblings = 0;
1954                 list_del_init(&rt->fib6_siblings);
1955                 rt6_multipath_rebalance(next_sibling);
1956         }
1957
1958         /* Adjust walkers */
1959         read_lock(&net->ipv6.fib6_walker_lock);
1960         FOR_WALKERS(net, w) {
1961                 if (w->state == FWS_C && w->leaf == rt) {
1962                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1963                         w->leaf = rcu_dereference_protected(rt->fib6_next,
1964                                             lockdep_is_held(&table->tb6_lock));
1965                         if (!w->leaf)
1966                                 w->state = FWS_U;
1967                 }
1968         }
1969         read_unlock(&net->ipv6.fib6_walker_lock);
1970
1971         /* If it was last route, call fib6_repair_tree() to:
1972          * 1. For root node, put back null_entry as how the table was created.
1973          * 2. For other nodes, expunge its radix tree node.
1974          */
1975         if (!rcu_access_pointer(fn->leaf)) {
1976                 if (!(fn->fn_flags & RTN_TL_ROOT)) {
1977                         fn->fn_flags &= ~RTN_RTINFO;
1978                         net->ipv6.rt6_stats->fib_route_nodes--;
1979                 }
1980                 fn = fib6_repair_tree(net, table, fn);
1981         }
1982
1983         fib6_purge_rt(rt, fn, net);
1984
1985         if (!info->skip_notify_kernel) {
1986                 if (notify_del)
1987                         call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
1988                                                   rt, NULL);
1989                 else if (replace_rt)
1990                         call_fib6_entry_notifiers_replace(net, replace_rt);
1991         }
1992         if (!info->skip_notify)
1993                 inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
1994
1995         fib6_info_release(rt);
1996 }
1997
1998 /* Need to own table->tb6_lock */
1999 int fib6_del(struct fib6_info *rt, struct nl_info *info)
2000 {
2001         struct net *net = info->nl_net;
2002         struct fib6_info __rcu **rtp;
2003         struct fib6_info __rcu **rtp_next;
2004         struct fib6_table *table;
2005         struct fib6_node *fn;
2006
2007         if (rt == net->ipv6.fib6_null_entry)
2008                 return -ENOENT;
2009
2010         table = rt->fib6_table;
2011         fn = rcu_dereference_protected(rt->fib6_node,
2012                                        lockdep_is_held(&table->tb6_lock));
2013         if (!fn)
2014                 return -ENOENT;
2015
2016         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
2017
2018         /*
2019          *      Walk the leaf entries looking for ourself
2020          */
2021
2022         for (rtp = &fn->leaf; *rtp; rtp = rtp_next) {
2023                 struct fib6_info *cur = rcu_dereference_protected(*rtp,
2024                                         lockdep_is_held(&table->tb6_lock));
2025                 if (rt == cur) {
2026                         if (fib6_requires_src(cur))
2027                                 fib6_routes_require_src_dec(info->nl_net);
2028                         fib6_del_route(table, fn, rtp, info);
2029                         return 0;
2030                 }
2031                 rtp_next = &cur->fib6_next;
2032         }
2033         return -ENOENT;
2034 }
2035
2036 /*
2037  *      Tree traversal function.
2038  *
2039  *      Certainly, it is not interrupt safe.
2040  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
2041  *      It means, that we can modify tree during walking
2042  *      and use this function for garbage collection, clone pruning,
2043  *      cleaning tree when a device goes down etc. etc.
2044  *
2045  *      It guarantees that every node will be traversed,
2046  *      and that it will be traversed only once.
2047  *
2048  *      Callback function w->func may return:
2049  *      0 -> continue walking.
2050  *      positive value -> walking is suspended (used by tree dumps,
2051  *      and probably by gc, if it will be split to several slices)
2052  *      negative value -> terminate walking.
2053  *
2054  *      The function itself returns:
2055  *      0   -> walk is complete.
2056  *      >0  -> walk is incomplete (i.e. suspended)
2057  *      <0  -> walk is terminated by an error.
2058  *
2059  *      This function is called with tb6_lock held.
2060  */
2061
2062 static int fib6_walk_continue(struct fib6_walker *w)
2063 {
2064         struct fib6_node *fn, *pn, *left, *right;
2065
2066         /* w->root should always be table->tb6_root */
2067         WARN_ON_ONCE(!(w->root->fn_flags & RTN_TL_ROOT));
2068
2069         for (;;) {
2070                 fn = w->node;
2071                 if (!fn)
2072                         return 0;
2073
2074                 switch (w->state) {
2075 #ifdef CONFIG_IPV6_SUBTREES
2076                 case FWS_S:
2077                         if (FIB6_SUBTREE(fn)) {
2078                                 w->node = FIB6_SUBTREE(fn);
2079                                 continue;
2080                         }
2081                         w->state = FWS_L;
2082                         fallthrough;
2083 #endif
2084                 case FWS_L:
2085                         left = rcu_dereference_protected(fn->left, 1);
2086                         if (left) {
2087                                 w->node = left;
2088                                 w->state = FWS_INIT;
2089                                 continue;
2090                         }
2091                         w->state = FWS_R;
2092                         fallthrough;
2093                 case FWS_R:
2094                         right = rcu_dereference_protected(fn->right, 1);
2095                         if (right) {
2096                                 w->node = right;
2097                                 w->state = FWS_INIT;
2098                                 continue;
2099                         }
2100                         w->state = FWS_C;
2101                         w->leaf = rcu_dereference_protected(fn->leaf, 1);
2102                         fallthrough;
2103                 case FWS_C:
2104                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
2105                                 int err;
2106
2107                                 if (w->skip) {
2108                                         w->skip--;
2109                                         goto skip;
2110                                 }
2111
2112                                 err = w->func(w);
2113                                 if (err)
2114                                         return err;
2115
2116                                 w->count++;
2117                                 continue;
2118                         }
2119 skip:
2120                         w->state = FWS_U;
2121                         fallthrough;
2122                 case FWS_U:
2123                         if (fn == w->root)
2124                                 return 0;
2125                         pn = rcu_dereference_protected(fn->parent, 1);
2126                         left = rcu_dereference_protected(pn->left, 1);
2127                         right = rcu_dereference_protected(pn->right, 1);
2128                         w->node = pn;
2129 #ifdef CONFIG_IPV6_SUBTREES
2130                         if (FIB6_SUBTREE(pn) == fn) {
2131                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
2132                                 w->state = FWS_L;
2133                                 continue;
2134                         }
2135 #endif
2136                         if (left == fn) {
2137                                 w->state = FWS_R;
2138                                 continue;
2139                         }
2140                         if (right == fn) {
2141                                 w->state = FWS_C;
2142                                 w->leaf = rcu_dereference_protected(w->node->leaf, 1);
2143                                 continue;
2144                         }
2145 #if RT6_DEBUG >= 2
2146                         WARN_ON(1);
2147 #endif
2148                 }
2149         }
2150 }
2151
2152 static int fib6_walk(struct net *net, struct fib6_walker *w)
2153 {
2154         int res;
2155
2156         w->state = FWS_INIT;
2157         w->node = w->root;
2158
2159         fib6_walker_link(net, w);
2160         res = fib6_walk_continue(w);
2161         if (res <= 0)
2162                 fib6_walker_unlink(net, w);
2163         return res;
2164 }
2165
2166 static int fib6_clean_node(struct fib6_walker *w)
2167 {
2168         int res;
2169         struct fib6_info *rt;
2170         struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
2171         struct nl_info info = {
2172                 .nl_net = c->net,
2173                 .skip_notify = c->skip_notify,
2174         };
2175
2176         if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
2177             w->node->fn_sernum != c->sernum)
2178                 w->node->fn_sernum = c->sernum;
2179
2180         if (!c->func) {
2181                 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
2182                 w->leaf = NULL;
2183                 return 0;
2184         }
2185
2186         for_each_fib6_walker_rt(w) {
2187                 res = c->func(rt, c->arg);
2188                 if (res == -1) {
2189                         w->leaf = rt;
2190                         res = fib6_del(rt, &info);
2191                         if (res) {
2192 #if RT6_DEBUG >= 2
2193                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
2194                                          __func__, rt,
2195                                          rcu_access_pointer(rt->fib6_node),
2196                                          res);
2197 #endif
2198                                 continue;
2199                         }
2200                         return 0;
2201                 } else if (res == -2) {
2202                         if (WARN_ON(!rt->fib6_nsiblings))
2203                                 continue;
2204                         rt = list_last_entry(&rt->fib6_siblings,
2205                                              struct fib6_info, fib6_siblings);
2206                         continue;
2207                 }
2208                 WARN_ON(res != 0);
2209         }
2210         w->leaf = rt;
2211         return 0;
2212 }
2213
2214 /*
2215  *      Convenient frontend to tree walker.
2216  *
2217  *      func is called on each route.
2218  *              It may return -2 -> skip multipath route.
2219  *                            -1 -> delete this route.
2220  *                            0  -> continue walking
2221  */
2222
2223 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
2224                             int (*func)(struct fib6_info *, void *arg),
2225                             int sernum, void *arg, bool skip_notify)
2226 {
2227         struct fib6_cleaner c;
2228
2229         c.w.root = root;
2230         c.w.func = fib6_clean_node;
2231         c.w.count = 0;
2232         c.w.skip = 0;
2233         c.w.skip_in_node = 0;
2234         c.func = func;
2235         c.sernum = sernum;
2236         c.arg = arg;
2237         c.net = net;
2238         c.skip_notify = skip_notify;
2239
2240         fib6_walk(net, &c.w);
2241 }
2242
2243 static void __fib6_clean_all(struct net *net,
2244                              int (*func)(struct fib6_info *, void *),
2245                              int sernum, void *arg, bool skip_notify)
2246 {
2247         struct fib6_table *table;
2248         struct hlist_head *head;
2249         unsigned int h;
2250
2251         rcu_read_lock();
2252         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
2253                 head = &net->ipv6.fib_table_hash[h];
2254                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
2255                         spin_lock_bh(&table->tb6_lock);
2256                         fib6_clean_tree(net, &table->tb6_root,
2257                                         func, sernum, arg, skip_notify);
2258                         spin_unlock_bh(&table->tb6_lock);
2259                 }
2260         }
2261         rcu_read_unlock();
2262 }
2263
2264 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *),
2265                     void *arg)
2266 {
2267         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, false);
2268 }
2269
2270 void fib6_clean_all_skip_notify(struct net *net,
2271                                 int (*func)(struct fib6_info *, void *),
2272                                 void *arg)
2273 {
2274         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, true);
2275 }
2276
2277 static void fib6_flush_trees(struct net *net)
2278 {
2279         int new_sernum = fib6_new_sernum(net);
2280
2281         __fib6_clean_all(net, NULL, new_sernum, NULL, false);
2282 }
2283
2284 /*
2285  *      Garbage collection
2286  */
2287
2288 static int fib6_age(struct fib6_info *rt, void *arg)
2289 {
2290         struct fib6_gc_args *gc_args = arg;
2291         unsigned long now = jiffies;
2292
2293         /*
2294          *      check addrconf expiration here.
2295          *      Routes are expired even if they are in use.
2296          */
2297
2298         if (rt->fib6_flags & RTF_EXPIRES && rt->expires) {
2299                 if (time_after(now, rt->expires)) {
2300                         RT6_TRACE("expiring %p\n", rt);
2301                         return -1;
2302                 }
2303                 gc_args->more++;
2304         }
2305
2306         /*      Also age clones in the exception table.
2307          *      Note, that clones are aged out
2308          *      only if they are not in use now.
2309          */
2310         rt6_age_exceptions(rt, gc_args, now);
2311
2312         return 0;
2313 }
2314
2315 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
2316 {
2317         struct fib6_gc_args gc_args;
2318         unsigned long now;
2319
2320         if (force) {
2321                 spin_lock_bh(&net->ipv6.fib6_gc_lock);
2322         } else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
2323                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
2324                 return;
2325         }
2326         gc_args.timeout = expires ? (int)expires :
2327                           net->ipv6.sysctl.ip6_rt_gc_interval;
2328         gc_args.more = 0;
2329
2330         fib6_clean_all(net, fib6_age, &gc_args);
2331         now = jiffies;
2332         net->ipv6.ip6_rt_last_gc = now;
2333
2334         if (gc_args.more)
2335                 mod_timer(&net->ipv6.ip6_fib_timer,
2336                           round_jiffies(now
2337                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
2338         else
2339                 del_timer(&net->ipv6.ip6_fib_timer);
2340         spin_unlock_bh(&net->ipv6.fib6_gc_lock);
2341 }
2342
2343 static void fib6_gc_timer_cb(struct timer_list *t)
2344 {
2345         struct net *arg = from_timer(arg, t, ipv6.ip6_fib_timer);
2346
2347         fib6_run_gc(0, arg, true);
2348 }
2349
2350 static int __net_init fib6_net_init(struct net *net)
2351 {
2352         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
2353         int err;
2354
2355         err = fib6_notifier_init(net);
2356         if (err)
2357                 return err;
2358
2359         /* Default to 3-tuple */
2360         net->ipv6.sysctl.multipath_hash_fields =
2361                 FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
2362
2363         spin_lock_init(&net->ipv6.fib6_gc_lock);
2364         rwlock_init(&net->ipv6.fib6_walker_lock);
2365         INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
2366         timer_setup(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, 0);
2367
2368         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
2369         if (!net->ipv6.rt6_stats)
2370                 goto out_notifier;
2371
2372         /* Avoid false sharing : Use at least a full cache line */
2373         size = max_t(size_t, size, L1_CACHE_BYTES);
2374
2375         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
2376         if (!net->ipv6.fib_table_hash)
2377                 goto out_rt6_stats;
2378
2379         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
2380                                           GFP_KERNEL);
2381         if (!net->ipv6.fib6_main_tbl)
2382                 goto out_fib_table_hash;
2383
2384         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
2385         rcu_assign_pointer(net->ipv6.fib6_main_tbl->tb6_root.leaf,
2386                            net->ipv6.fib6_null_entry);
2387         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
2388                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2389         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
2390
2391 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2392         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
2393                                            GFP_KERNEL);
2394         if (!net->ipv6.fib6_local_tbl)
2395                 goto out_fib6_main_tbl;
2396         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
2397         rcu_assign_pointer(net->ipv6.fib6_local_tbl->tb6_root.leaf,
2398                            net->ipv6.fib6_null_entry);
2399         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
2400                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2401         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
2402 #endif
2403         fib6_tables_init(net);
2404
2405         return 0;
2406
2407 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2408 out_fib6_main_tbl:
2409         kfree(net->ipv6.fib6_main_tbl);
2410 #endif
2411 out_fib_table_hash:
2412         kfree(net->ipv6.fib_table_hash);
2413 out_rt6_stats:
2414         kfree(net->ipv6.rt6_stats);
2415 out_notifier:
2416         fib6_notifier_exit(net);
2417         return -ENOMEM;
2418 }
2419
2420 static void fib6_net_exit(struct net *net)
2421 {
2422         unsigned int i;
2423
2424         del_timer_sync(&net->ipv6.ip6_fib_timer);
2425
2426         for (i = 0; i < FIB6_TABLE_HASHSZ; i++) {
2427                 struct hlist_head *head = &net->ipv6.fib_table_hash[i];
2428                 struct hlist_node *tmp;
2429                 struct fib6_table *tb;
2430
2431                 hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
2432                         hlist_del(&tb->tb6_hlist);
2433                         fib6_free_table(tb);
2434                 }
2435         }
2436
2437         kfree(net->ipv6.fib_table_hash);
2438         kfree(net->ipv6.rt6_stats);
2439         fib6_notifier_exit(net);
2440 }
2441
2442 static struct pernet_operations fib6_net_ops = {
2443         .init = fib6_net_init,
2444         .exit = fib6_net_exit,
2445 };
2446
2447 int __init fib6_init(void)
2448 {
2449         int ret = -ENOMEM;
2450
2451         fib6_node_kmem = kmem_cache_create("fib6_nodes",
2452                                            sizeof(struct fib6_node),
2453                                            0, SLAB_HWCACHE_ALIGN,
2454                                            NULL);
2455         if (!fib6_node_kmem)
2456                 goto out;
2457
2458         ret = register_pernet_subsys(&fib6_net_ops);
2459         if (ret)
2460                 goto out_kmem_cache_create;
2461
2462         ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETROUTE, NULL,
2463                                    inet6_dump_fib, 0);
2464         if (ret)
2465                 goto out_unregister_subsys;
2466
2467         __fib6_flush_trees = fib6_flush_trees;
2468 out:
2469         return ret;
2470
2471 out_unregister_subsys:
2472         unregister_pernet_subsys(&fib6_net_ops);
2473 out_kmem_cache_create:
2474         kmem_cache_destroy(fib6_node_kmem);
2475         goto out;
2476 }
2477
2478 void fib6_gc_cleanup(void)
2479 {
2480         unregister_pernet_subsys(&fib6_net_ops);
2481         kmem_cache_destroy(fib6_node_kmem);
2482 }
2483
2484 #ifdef CONFIG_PROC_FS
2485 static int ipv6_route_native_seq_show(struct seq_file *seq, void *v)
2486 {
2487         struct fib6_info *rt = v;
2488         struct ipv6_route_iter *iter = seq->private;
2489         struct fib6_nh *fib6_nh = rt->fib6_nh;
2490         unsigned int flags = rt->fib6_flags;
2491         const struct net_device *dev;
2492
2493         if (rt->nh)
2494                 fib6_nh = nexthop_fib6_nh_bh(rt->nh);
2495
2496         seq_printf(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen);
2497
2498 #ifdef CONFIG_IPV6_SUBTREES
2499         seq_printf(seq, "%pi6 %02x ", &rt->fib6_src.addr, rt->fib6_src.plen);
2500 #else
2501         seq_puts(seq, "00000000000000000000000000000000 00 ");
2502 #endif
2503         if (fib6_nh->fib_nh_gw_family) {
2504                 flags |= RTF_GATEWAY;
2505                 seq_printf(seq, "%pi6", &fib6_nh->fib_nh_gw6);
2506         } else {
2507                 seq_puts(seq, "00000000000000000000000000000000");
2508         }
2509
2510         dev = fib6_nh->fib_nh_dev;
2511         seq_printf(seq, " %08x %08x %08x %08x %8s\n",
2512                    rt->fib6_metric, refcount_read(&rt->fib6_ref), 0,
2513                    flags, dev ? dev->name : "");
2514         iter->w.leaf = NULL;
2515         return 0;
2516 }
2517
2518 static int ipv6_route_yield(struct fib6_walker *w)
2519 {
2520         struct ipv6_route_iter *iter = w->args;
2521
2522         if (!iter->skip)
2523                 return 1;
2524
2525         do {
2526                 iter->w.leaf = rcu_dereference_protected(
2527                                 iter->w.leaf->fib6_next,
2528                                 lockdep_is_held(&iter->tbl->tb6_lock));
2529                 iter->skip--;
2530                 if (!iter->skip && iter->w.leaf)
2531                         return 1;
2532         } while (iter->w.leaf);
2533
2534         return 0;
2535 }
2536
2537 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
2538                                       struct net *net)
2539 {
2540         memset(&iter->w, 0, sizeof(iter->w));
2541         iter->w.func = ipv6_route_yield;
2542         iter->w.root = &iter->tbl->tb6_root;
2543         iter->w.state = FWS_INIT;
2544         iter->w.node = iter->w.root;
2545         iter->w.args = iter;
2546         iter->sernum = iter->w.root->fn_sernum;
2547         INIT_LIST_HEAD(&iter->w.lh);
2548         fib6_walker_link(net, &iter->w);
2549 }
2550
2551 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
2552                                                     struct net *net)
2553 {
2554         unsigned int h;
2555         struct hlist_node *node;
2556
2557         if (tbl) {
2558                 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
2559                 node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
2560         } else {
2561                 h = 0;
2562                 node = NULL;
2563         }
2564
2565         while (!node && h < FIB6_TABLE_HASHSZ) {
2566                 node = rcu_dereference_bh(
2567                         hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
2568         }
2569         return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
2570 }
2571
2572 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
2573 {
2574         if (iter->sernum != iter->w.root->fn_sernum) {
2575                 iter->sernum = iter->w.root->fn_sernum;
2576                 iter->w.state = FWS_INIT;
2577                 iter->w.node = iter->w.root;
2578                 WARN_ON(iter->w.skip);
2579                 iter->w.skip = iter->w.count;
2580         }
2581 }
2582
2583 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2584 {
2585         int r;
2586         struct fib6_info *n;
2587         struct net *net = seq_file_net(seq);
2588         struct ipv6_route_iter *iter = seq->private;
2589
2590         ++(*pos);
2591         if (!v)
2592                 goto iter_table;
2593
2594         n = rcu_dereference_bh(((struct fib6_info *)v)->fib6_next);
2595         if (n)
2596                 return n;
2597
2598 iter_table:
2599         ipv6_route_check_sernum(iter);
2600         spin_lock_bh(&iter->tbl->tb6_lock);
2601         r = fib6_walk_continue(&iter->w);
2602         spin_unlock_bh(&iter->tbl->tb6_lock);
2603         if (r > 0) {
2604                 return iter->w.leaf;
2605         } else if (r < 0) {
2606                 fib6_walker_unlink(net, &iter->w);
2607                 return NULL;
2608         }
2609         fib6_walker_unlink(net, &iter->w);
2610
2611         iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
2612         if (!iter->tbl)
2613                 return NULL;
2614
2615         ipv6_route_seq_setup_walk(iter, net);
2616         goto iter_table;
2617 }
2618
2619 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
2620         __acquires(RCU_BH)
2621 {
2622         struct net *net = seq_file_net(seq);
2623         struct ipv6_route_iter *iter = seq->private;
2624
2625         rcu_read_lock_bh();
2626         iter->tbl = ipv6_route_seq_next_table(NULL, net);
2627         iter->skip = *pos;
2628
2629         if (iter->tbl) {
2630                 loff_t p = 0;
2631
2632                 ipv6_route_seq_setup_walk(iter, net);
2633                 return ipv6_route_seq_next(seq, NULL, &p);
2634         } else {
2635                 return NULL;
2636         }
2637 }
2638
2639 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
2640 {
2641         struct fib6_walker *w = &iter->w;
2642         return w->node && !(w->state == FWS_U && w->node == w->root);
2643 }
2644
2645 static void ipv6_route_native_seq_stop(struct seq_file *seq, void *v)
2646         __releases(RCU_BH)
2647 {
2648         struct net *net = seq_file_net(seq);
2649         struct ipv6_route_iter *iter = seq->private;
2650
2651         if (ipv6_route_iter_active(iter))
2652                 fib6_walker_unlink(net, &iter->w);
2653
2654         rcu_read_unlock_bh();
2655 }
2656
2657 #if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
2658 static int ipv6_route_prog_seq_show(struct bpf_prog *prog,
2659                                     struct bpf_iter_meta *meta,
2660                                     void *v)
2661 {
2662         struct bpf_iter__ipv6_route ctx;
2663
2664         ctx.meta = meta;
2665         ctx.rt = v;
2666         return bpf_iter_run_prog(prog, &ctx);
2667 }
2668
2669 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2670 {
2671         struct ipv6_route_iter *iter = seq->private;
2672         struct bpf_iter_meta meta;
2673         struct bpf_prog *prog;
2674         int ret;
2675
2676         meta.seq = seq;
2677         prog = bpf_iter_get_info(&meta, false);
2678         if (!prog)
2679                 return ipv6_route_native_seq_show(seq, v);
2680
2681         ret = ipv6_route_prog_seq_show(prog, &meta, v);
2682         iter->w.leaf = NULL;
2683
2684         return ret;
2685 }
2686
2687 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2688 {
2689         struct bpf_iter_meta meta;
2690         struct bpf_prog *prog;
2691
2692         if (!v) {
2693                 meta.seq = seq;
2694                 prog = bpf_iter_get_info(&meta, true);
2695                 if (prog)
2696                         (void)ipv6_route_prog_seq_show(prog, &meta, v);
2697         }
2698
2699         ipv6_route_native_seq_stop(seq, v);
2700 }
2701 #else
2702 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2703 {
2704         return ipv6_route_native_seq_show(seq, v);
2705 }
2706
2707 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2708 {
2709         ipv6_route_native_seq_stop(seq, v);
2710 }
2711 #endif
2712
2713 const struct seq_operations ipv6_route_seq_ops = {
2714         .start  = ipv6_route_seq_start,
2715         .next   = ipv6_route_seq_next,
2716         .stop   = ipv6_route_seq_stop,
2717         .show   = ipv6_route_seq_show
2718 };
2719 #endif /* CONFIG_PROC_FS */