net/ipv6/ip6_fib.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Linux INET6 implementation
   4  *      Forwarding Information Database
   5  *
   6  *      Authors:
   7  *      Pedro Roque             <roque@di.fc.ul.pt>
   8  *
   9  *      Changes:
  10  *      Yuji SEKIYA @USAGI:     Support default route on router node;
  11  *                              remove ip6_null_entry from the top of
  12  *                              routing table.
  13  *      Ville Nuorvala:         Fixed routing subtrees.
  14  */
  15
  16 #define pr_fmt(fmt) "IPv6: " fmt
  17
  18 #include <linux/bpf.h>
  19 #include <linux/errno.h>
  20 #include <linux/types.h>
  21 #include <linux/net.h>
  22 #include <linux/route.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/in6.h>
  25 #include <linux/init.h>
  26 #include <linux/list.h>
  27 #include <linux/slab.h>
  28
  29 #include <net/ip.h>
  30 #include <net/ipv6.h>
  31 #include <net/ndisc.h>
  32 #include <net/addrconf.h>
  33 #include <net/lwtunnel.h>
  34 #include <net/fib_notifier.h>
  35
  36 #include <net/ip_fib.h>
  37 #include <net/ip6_fib.h>
  38 #include <net/ip6_route.h>
  39
  40 static struct kmem_cache *fib6_node_kmem __read_mostly;
  41
  42 struct fib6_cleaner {
  43         struct fib6_walker w;
  44         struct net *net;
  45         int (*func)(struct fib6_info *, void *arg);
  46         int sernum;
  47         void *arg;
  48         bool skip_notify;
  49 };
  50
  51 #ifdef CONFIG_IPV6_SUBTREES
  52 #define FWS_INIT FWS_S
  53 #else
  54 #define FWS_INIT FWS_L
  55 #endif
  56
  57 static struct fib6_info *fib6_find_prefix(struct net *net,
  58                                          struct fib6_table *table,
  59                                          struct fib6_node *fn);
  60 static struct fib6_node *fib6_repair_tree(struct net *net,
  61                                           struct fib6_table *table,
  62                                           struct fib6_node *fn);
  63 static int fib6_walk(struct net *net, struct fib6_walker *w);
  64 static int fib6_walk_continue(struct fib6_walker *w);
  65
  66 /*
  67  *      A routing update causes an increase of the serial number on the
  68  *      affected subtree. This allows for cached routes to be asynchronously
  69  *      tested when modifications are made to the destination cache as a
  70  *      result of redirects, path MTU changes, etc.
  71  */
  72
  73 static void fib6_gc_timer_cb(struct timer_list *t);
  74
  75 #define FOR_WALKERS(net, w) \
  76         list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)
  77
  78 static void fib6_walker_link(struct net *net, struct fib6_walker *w)
  79 {
  80         write_lock_bh(&net->ipv6.fib6_walker_lock);
  81         list_add(&w->lh, &net->ipv6.fib6_walkers);
  82         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  83 }
  84
  85 static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
  86 {
  87         write_lock_bh(&net->ipv6.fib6_walker_lock);
  88         list_del(&w->lh);
  89         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  90 }
  91
  92 static int fib6_new_sernum(struct net *net)
  93 {
  94         int new, old = atomic_read(&net->ipv6.fib6_sernum);
  95
  96         do {
  97                 new = old < INT_MAX ? old + 1 : 1;
  98         } while (!atomic_try_cmpxchg(&net->ipv6.fib6_sernum, &old, new));
  99
 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                 WRITE_ONCE(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         INIT_HLIST_NODE(&f6i->gc_link);
 164
 165         return f6i;
 166 }
 167
 168 void fib6_info_destroy_rcu(struct rcu_head *head)
 169 {
 170         struct fib6_info *f6i = container_of(head, struct fib6_info, rcu);
 171
 172         WARN_ON(f6i->fib6_node);
 173
 174         if (f6i->nh)
 175                 nexthop_put(f6i->nh);
 176         else
 177                 fib6_nh_release(f6i->fib6_nh);
 178
 179         ip_fib_metrics_put(f6i->fib6_metrics);
 180         kfree(f6i);
 181 }
 182 EXPORT_SYMBOL_GPL(fib6_info_destroy_rcu);
 183
 184 static struct fib6_node *node_alloc(struct net *net)
 185 {
 186         struct fib6_node *fn;
 187
 188         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 189         if (fn)
 190                 net->ipv6.rt6_stats->fib_nodes++;
 191
 192         return fn;
 193 }
 194
 195 static void node_free_immediate(struct net *net, struct fib6_node *fn)
 196 {
 197         kmem_cache_free(fib6_node_kmem, fn);
 198         net->ipv6.rt6_stats->fib_nodes--;
 199 }
 200
 201 static void node_free_rcu(struct rcu_head *head)
 202 {
 203         struct fib6_node *fn = container_of(head, struct fib6_node, rcu);
 204
 205         kmem_cache_free(fib6_node_kmem, fn);
 206 }
 207
 208 static void node_free(struct net *net, struct fib6_node *fn)
 209 {
 210         call_rcu(&fn->rcu, node_free_rcu);
 211         net->ipv6.rt6_stats->fib_nodes--;
 212 }
 213
 214 static void fib6_free_table(struct fib6_table *table)
 215 {
 216         inetpeer_invalidate_tree(&table->tb6_peers);
 217         kfree(table);
 218 }
 219
 220 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 221 {
 222         unsigned int h;
 223
 224         /*
 225          * Initialize table lock at a single place to give lockdep a key,
 226          * tables aren't visible prior to being linked to the list.
 227          */
 228         spin_lock_init(&tb->tb6_lock);
 229         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 230
 231         /*
 232          * No protection necessary, this is the only list mutatation
 233          * operation, tables never disappear once they exist.
 234          */
 235         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 236 }
 237
 238 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 239
 240 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 241 {
 242         struct fib6_table *table;
 243
 244         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 245         if (table) {
 246                 table->tb6_id = id;
 247                 rcu_assign_pointer(table->tb6_root.leaf,
 248                                    net->ipv6.fib6_null_entry);
 249                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 250                 inet_peer_base_init(&table->tb6_peers);
 251                 INIT_HLIST_HEAD(&table->tb6_gc_hlist);
 252         }
 253
 254         return table;
 255 }
 256
 257 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 258 {
 259         struct fib6_table *tb;
 260
 261         if (id == 0)
 262                 id = RT6_TABLE_MAIN;
 263         tb = fib6_get_table(net, id);
 264         if (tb)
 265                 return tb;
 266
 267         tb = fib6_alloc_table(net, id);
 268         if (tb)
 269                 fib6_link_table(net, tb);
 270
 271         return tb;
 272 }
 273 EXPORT_SYMBOL_GPL(fib6_new_table);
 274
 275 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 276 {
 277         struct fib6_table *tb;
 278         struct hlist_head *head;
 279         unsigned int h;
 280
 281         if (id == 0)
 282                 id = RT6_TABLE_MAIN;
 283         h = id & (FIB6_TABLE_HASHSZ - 1);
 284         rcu_read_lock();
 285         head = &net->ipv6.fib_table_hash[h];
 286         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 287                 if (tb->tb6_id == id) {
 288                         rcu_read_unlock();
 289                         return tb;
 290                 }
 291         }
 292         rcu_read_unlock();
 293
 294         return NULL;
 295 }
 296 EXPORT_SYMBOL_GPL(fib6_get_table);
 297
 298 static void __net_init fib6_tables_init(struct net *net)
 299 {
 300         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 301         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 302 }
 303 #else
 304
 305 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 306 {
 307         return fib6_get_table(net, id);
 308 }
 309
 310 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 311 {
 312           return net->ipv6.fib6_main_tbl;
 313 }
 314
 315 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 316                                    const struct sk_buff *skb,
 317                                    int flags, pol_lookup_t lookup)
 318 {
 319         struct rt6_info *rt;
 320
 321         rt = pol_lookup_func(lookup,
 322                         net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
 323         if (rt->dst.error == -EAGAIN) {
 324                 ip6_rt_put_flags(rt, flags);
 325                 rt = net->ipv6.ip6_null_entry;
 326                 if (!(flags & RT6_LOOKUP_F_DST_NOREF))
 327                         dst_hold(&rt->dst);
 328         }
 329
 330         return &rt->dst;
 331 }
 332
 333 /* called with rcu lock held; no reference taken on fib6_info */
 334 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 335                 struct fib6_result *res, int flags)
 336 {
 337         return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6,
 338                                  res, flags);
 339 }
 340
 341 static void __net_init fib6_tables_init(struct net *net)
 342 {
 343         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 344 }
 345
 346 #endif
 347
 348 unsigned int fib6_tables_seq_read(struct net *net)
 349 {
 350         unsigned int h, fib_seq = 0;
 351
 352         rcu_read_lock();
 353         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
 354                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
 355                 struct fib6_table *tb;
 356
 357                 hlist_for_each_entry_rcu(tb, head, tb6_hlist)
 358                         fib_seq += tb->fib_seq;
 359         }
 360         rcu_read_unlock();
 361
 362         return fib_seq;
 363 }
 364
 365 static int call_fib6_entry_notifier(struct notifier_block *nb,
 366                                     enum fib_event_type event_type,
 367                                     struct fib6_info *rt,
 368                                     struct netlink_ext_ack *extack)
 369 {
 370         struct fib6_entry_notifier_info info = {
 371                 .info.extack = extack,
 372                 .rt = rt,
 373         };
 374
 375         return call_fib6_notifier(nb, event_type, &info.info);
 376 }
 377
 378 static int call_fib6_multipath_entry_notifier(struct notifier_block *nb,
 379                                               enum fib_event_type event_type,
 380                                               struct fib6_info *rt,
 381                                               unsigned int nsiblings,
 382                                               struct netlink_ext_ack *extack)
 383 {
 384         struct fib6_entry_notifier_info info = {
 385                 .info.extack = extack,
 386                 .rt = rt,
 387                 .nsiblings = nsiblings,
 388         };
 389
 390         return call_fib6_notifier(nb, event_type, &info.info);
 391 }
 392
 393 int call_fib6_entry_notifiers(struct net *net,
 394                               enum fib_event_type event_type,
 395                               struct fib6_info *rt,
 396                               struct netlink_ext_ack *extack)
 397 {
 398         struct fib6_entry_notifier_info info = {
 399                 .info.extack = extack,
 400                 .rt = rt,
 401         };
 402
 403         rt->fib6_table->fib_seq++;
 404         return call_fib6_notifiers(net, event_type, &info.info);
 405 }
 406
 407 int call_fib6_multipath_entry_notifiers(struct net *net,
 408                                         enum fib_event_type event_type,
 409                                         struct fib6_info *rt,
 410                                         unsigned int nsiblings,
 411                                         struct netlink_ext_ack *extack)
 412 {
 413         struct fib6_entry_notifier_info info = {
 414                 .info.extack = extack,
 415                 .rt = rt,
 416                 .nsiblings = nsiblings,
 417         };
 418
 419         rt->fib6_table->fib_seq++;
 420         return call_fib6_notifiers(net, event_type, &info.info);
 421 }
 422
 423 int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt)
 424 {
 425         struct fib6_entry_notifier_info info = {
 426                 .rt = rt,
 427                 .nsiblings = rt->fib6_nsiblings,
 428         };
 429
 430         rt->fib6_table->fib_seq++;
 431         return call_fib6_notifiers(net, FIB_EVENT_ENTRY_REPLACE, &info.info);
 432 }
 433
 434 struct fib6_dump_arg {
 435         struct net *net;
 436         struct notifier_block *nb;
 437         struct netlink_ext_ack *extack;
 438 };
 439
 440 static int fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
 441 {
 442         enum fib_event_type fib_event = FIB_EVENT_ENTRY_REPLACE;
 443         int err;
 444
 445         if (!rt || rt == arg->net->ipv6.fib6_null_entry)
 446                 return 0;
 447
 448         if (rt->fib6_nsiblings)
 449                 err = call_fib6_multipath_entry_notifier(arg->nb, fib_event,
 450                                                          rt,
 451                                                          rt->fib6_nsiblings,
 452                                                          arg->extack);
 453         else
 454                 err = call_fib6_entry_notifier(arg->nb, fib_event, rt,
 455                                                arg->extack);
 456
 457         return err;
 458 }
 459
 460 static int fib6_node_dump(struct fib6_walker *w)
 461 {
 462         int err;
 463
 464         err = fib6_rt_dump(w->leaf, w->args);
 465         w->leaf = NULL;
 466         return err;
 467 }
 468
 469 static int fib6_table_dump(struct net *net, struct fib6_table *tb,
 470                            struct fib6_walker *w)
 471 {
 472         int err;
 473
 474         w->root = &tb->tb6_root;
 475         spin_lock_bh(&tb->tb6_lock);
 476         err = fib6_walk(net, w);
 477         spin_unlock_bh(&tb->tb6_lock);
 478         return err;
 479 }
 480
 481 /* Called with rcu_read_lock() */
 482 int fib6_tables_dump(struct net *net, struct notifier_block *nb,
 483                      struct netlink_ext_ack *extack)
 484 {
 485         struct fib6_dump_arg arg;
 486         struct fib6_walker *w;
 487         unsigned int h;
 488         int err = 0;
 489
 490         w = kzalloc(sizeof(*w), GFP_ATOMIC);
 491         if (!w)
 492                 return -ENOMEM;
 493
 494         w->func = fib6_node_dump;
 495         arg.net = net;
 496         arg.nb = nb;
 497         arg.extack = extack;
 498         w->args = &arg;
 499
 500         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
 501                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
 502                 struct fib6_table *tb;
 503
 504                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 505                         err = fib6_table_dump(net, tb, w);
 506                         if (err)
 507                                 goto out;
 508                 }
 509         }
 510
 511 out:
 512         kfree(w);
 513
 514         /* The tree traversal function should never return a positive value. */
 515         return err > 0 ? -EINVAL : err;
 516 }
 517
 518 static int fib6_dump_node(struct fib6_walker *w)
 519 {
 520         int res;
 521         struct fib6_info *rt;
 522
 523         for_each_fib6_walker_rt(w) {
 524                 res = rt6_dump_route(rt, w->args, w->skip_in_node);
 525                 if (res >= 0) {
 526                         /* Frame is full, suspend walking */
 527                         w->leaf = rt;
 528
 529                         /* We'll restart from this node, so if some routes were
 530                          * already dumped, skip them next time.
 531                          */
 532                         w->skip_in_node += res;
 533
 534                         return 1;
 535                 }
 536                 w->skip_in_node = 0;
 537
 538                 /* Multipath routes are dumped in one route with the
 539                  * RTA_MULTIPATH attribute. Jump 'rt' to point to the
 540                  * last sibling of this route (no need to dump the
 541                  * sibling routes again)
 542                  */
 543                 if (rt->fib6_nsiblings)
 544                         rt = list_last_entry(&rt->fib6_siblings,
 545                                              struct fib6_info,
 546                                              fib6_siblings);
 547         }
 548         w->leaf = NULL;
 549         return 0;
 550 }
 551
 552 static void fib6_dump_end(struct netlink_callback *cb)
 553 {
 554         struct net *net = sock_net(cb->skb->sk);
 555         struct fib6_walker *w = (void *)cb->args[2];
 556
 557         if (w) {
 558                 if (cb->args[4]) {
 559                         cb->args[4] = 0;
 560                         fib6_walker_unlink(net, w);
 561                 }
 562                 cb->args[2] = 0;
 563                 kfree(w);
 564         }
 565         cb->done = (void *)cb->args[3];
 566         cb->args[1] = 3;
 567 }
 568
 569 static int fib6_dump_done(struct netlink_callback *cb)
 570 {
 571         fib6_dump_end(cb);
 572         return cb->done ? cb->done(cb) : 0;
 573 }
 574
 575 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 576                            struct netlink_callback *cb)
 577 {
 578         struct net *net = sock_net(skb->sk);
 579         struct fib6_walker *w;
 580         int res;
 581
 582         w = (void *)cb->args[2];
 583         w->root = &table->tb6_root;
 584
 585         if (cb->args[4] == 0) {
 586                 w->count = 0;
 587                 w->skip = 0;
 588                 w->skip_in_node = 0;
 589
 590                 spin_lock_bh(&table->tb6_lock);
 591                 res = fib6_walk(net, w);
 592                 spin_unlock_bh(&table->tb6_lock);
 593                 if (res > 0) {
 594                         cb->args[4] = 1;
 595                         cb->args[5] = READ_ONCE(w->root->fn_sernum);
 596                 }
 597         } else {
 598                 int sernum = READ_ONCE(w->root->fn_sernum);
 599                 if (cb->args[5] != sernum) {
 600                         /* Begin at the root if the tree changed */
 601                         cb->args[5] = sernum;
 602                         w->state = FWS_INIT;
 603                         w->node = w->root;
 604                         w->skip = w->count;
 605                         w->skip_in_node = 0;
 606                 } else
 607                         w->skip = 0;
 608
 609                 spin_lock_bh(&table->tb6_lock);
 610                 res = fib6_walk_continue(w);
 611                 spin_unlock_bh(&table->tb6_lock);
 612                 if (res <= 0) {
 613                         fib6_walker_unlink(net, w);
 614                         cb->args[4] = 0;
 615                 }
 616         }
 617
 618         return res;
 619 }
 620
 621 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 622 {
 623         struct rt6_rtnl_dump_arg arg = { .filter.dump_exceptions = true,
 624                                          .filter.dump_routes = true };
 625         const struct nlmsghdr *nlh = cb->nlh;
 626         struct net *net = sock_net(skb->sk);
 627         unsigned int h, s_h;
 628         unsigned int e = 0, s_e;
 629         struct fib6_walker *w;
 630         struct fib6_table *tb;
 631         struct hlist_head *head;
 632         int res = 0;
 633
 634         if (cb->strict_check) {
 635                 int err;
 636
 637                 err = ip_valid_fib_dump_req(net, nlh, &arg.filter, cb);
 638                 if (err < 0)
 639                         return err;
 640         } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
 641                 struct rtmsg *rtm = nlmsg_data(nlh);
 642
 643                 if (rtm->rtm_flags & RTM_F_PREFIX)
 644                         arg.filter.flags = RTM_F_PREFIX;
 645         }
 646
 647         w = (void *)cb->args[2];
 648         if (!w) {
 649                 /* New dump:
 650                  *
 651                  * 1. hook callback destructor.
 652                  */
 653                 cb->args[3] = (long)cb->done;
 654                 cb->done = fib6_dump_done;
 655
 656                 /*
 657                  * 2. allocate and initialize walker.
 658                  */
 659                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 660                 if (!w)
 661                         return -ENOMEM;
 662                 w->func = fib6_dump_node;
 663                 cb->args[2] = (long)w;
 664         }
 665
 666         arg.skb = skb;
 667         arg.cb = cb;
 668         arg.net = net;
 669         w->args = &arg;
 670
 671         if (arg.filter.table_id) {
 672                 tb = fib6_get_table(net, arg.filter.table_id);
 673                 if (!tb) {
 674                         if (rtnl_msg_family(cb->nlh) != PF_INET6)
 675                                 goto out;
 676
 677                         NL_SET_ERR_MSG_MOD(cb->extack, "FIB table does not exist");
 678                         return -ENOENT;
 679                 }
 680
 681                 if (!cb->args[0]) {
 682                         res = fib6_dump_table(tb, skb, cb);
 683                         if (!res)
 684                                 cb->args[0] = 1;
 685                 }
 686                 goto out;
 687         }
 688
 689         s_h = cb->args[0];
 690         s_e = cb->args[1];
 691
 692         rcu_read_lock();
 693         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 694                 e = 0;
 695                 head = &net->ipv6.fib_table_hash[h];
 696                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 697                         if (e < s_e)
 698                                 goto next;
 699                         res = fib6_dump_table(tb, skb, cb);
 700                         if (res != 0)
 701                                 goto out_unlock;
 702 next:
 703                         e++;
 704                 }
 705         }
 706 out_unlock:
 707         rcu_read_unlock();
 708         cb->args[1] = e;
 709         cb->args[0] = h;
 710 out:
 711         res = res < 0 ? res : skb->len;
 712         if (res <= 0)
 713                 fib6_dump_end(cb);
 714         return res;
 715 }
 716
 717 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val)
 718 {
 719         if (!f6i)
 720                 return;
 721
 722         if (f6i->fib6_metrics == &dst_default_metrics) {
 723                 struct dst_metrics *p = kzalloc(sizeof(*p), GFP_ATOMIC);
 724
 725                 if (!p)
 726                         return;
 727
 728                 refcount_set(&p->refcnt, 1);
 729                 f6i->fib6_metrics = p;
 730         }
 731
 732         f6i->fib6_metrics->metrics[metric - 1] = val;
 733 }
 734
 735 /*
 736  *      Routing Table
 737  *
 738  *      return the appropriate node for a routing tree "add" operation
 739  *      by either creating and inserting or by returning an existing
 740  *      node.
 741  */
 742
 743 static struct fib6_node *fib6_add_1(struct net *net,
 744                                     struct fib6_table *table,
 745                                     struct fib6_node *root,
 746                                     struct in6_addr *addr, int plen,
 747                                     int offset, int allow_create,
 748                                     int replace_required,
 749                                     struct netlink_ext_ack *extack)
 750 {
 751         struct fib6_node *fn, *in, *ln;
 752         struct fib6_node *pn = NULL;
 753         struct rt6key *key;
 754         int     bit;
 755         __be32  dir = 0;
 756
 757         RT6_TRACE("fib6_add_1\n");
 758
 759         /* insert node in tree */
 760
 761         fn = root;
 762
 763         do {
 764                 struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
 765                                             lockdep_is_held(&table->tb6_lock));
 766                 key = (struct rt6key *)((u8 *)leaf + offset);
 767
 768                 /*
 769                  *      Prefix match
 770                  */
 771                 if (plen < fn->fn_bit ||
 772                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 773                         if (!allow_create) {
 774                                 if (replace_required) {
 775                                         NL_SET_ERR_MSG(extack,
 776                                                        "Can not replace route - no match found");
 777                                         pr_warn("Can't replace route, no match found\n");
 778                                         return ERR_PTR(-ENOENT);
 779                                 }
 780                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 781                         }
 782                         goto insert_above;
 783                 }
 784
 785                 /*
 786                  *      Exact match ?
 787                  */
 788
 789                 if (plen == fn->fn_bit) {
 790                         /* clean up an intermediate node */
 791                         if (!(fn->fn_flags & RTN_RTINFO)) {
 792                                 RCU_INIT_POINTER(fn->leaf, NULL);
 793                                 fib6_info_release(leaf);
 794                         /* remove null_entry in the root node */
 795                         } else if (fn->fn_flags & RTN_TL_ROOT &&
 796                                    rcu_access_pointer(fn->leaf) ==
 797                                    net->ipv6.fib6_null_entry) {
 798                                 RCU_INIT_POINTER(fn->leaf, NULL);
 799                         }
 800
 801                         return fn;
 802                 }
 803
 804                 /*
 805                  *      We have more bits to go
 806                  */
 807
 808                 /* Try to walk down on tree. */
 809                 dir = addr_bit_set(addr, fn->fn_bit);
 810                 pn = fn;
 811                 fn = dir ?
 812                      rcu_dereference_protected(fn->right,
 813                                         lockdep_is_held(&table->tb6_lock)) :
 814                      rcu_dereference_protected(fn->left,
 815                                         lockdep_is_held(&table->tb6_lock));
 816         } while (fn);
 817
 818         if (!allow_create) {
 819                 /* We should not create new node because
 820                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 821                  * I assume it is safe to require NLM_F_CREATE when
 822                  * REPLACE flag is used! Later we may want to remove the
 823                  * check for replace_required, because according
 824                  * to netlink specification, NLM_F_CREATE
 825                  * MUST be specified if new route is created.
 826                  * That would keep IPv6 consistent with IPv4
 827                  */
 828                 if (replace_required) {
 829                         NL_SET_ERR_MSG(extack,
 830                                        "Can not replace route - no match found");
 831                         pr_warn("Can't replace route, no match found\n");
 832                         return ERR_PTR(-ENOENT);
 833                 }
 834                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 835         }
 836         /*
 837          *      We walked to the bottom of tree.
 838          *      Create new leaf node without children.
 839          */
 840
 841         ln = node_alloc(net);
 842
 843         if (!ln)
 844                 return ERR_PTR(-ENOMEM);
 845         ln->fn_bit = plen;
 846         RCU_INIT_POINTER(ln->parent, pn);
 847
 848         if (dir)
 849                 rcu_assign_pointer(pn->right, ln);
 850         else
 851                 rcu_assign_pointer(pn->left, ln);
 852
 853         return ln;
 854
 855
 856 insert_above:
 857         /*
 858          * split since we don't have a common prefix anymore or
 859          * we have a less significant route.
 860          * we've to insert an intermediate node on the list
 861          * this new node will point to the one we need to create
 862          * and the current
 863          */
 864
 865         pn = rcu_dereference_protected(fn->parent,
 866                                        lockdep_is_held(&table->tb6_lock));
 867
 868         /* find 1st bit in difference between the 2 addrs.
 869
 870            See comment in __ipv6_addr_diff: bit may be an invalid value,
 871            but if it is >= plen, the value is ignored in any case.
 872          */
 873
 874         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 875
 876         /*
 877          *              (intermediate)[in]
 878          *                /        \
 879          *      (new leaf node)[ln] (old node)[fn]
 880          */
 881         if (plen > bit) {
 882                 in = node_alloc(net);
 883                 ln = node_alloc(net);
 884
 885                 if (!in || !ln) {
 886                         if (in)
 887                                 node_free_immediate(net, in);
 888                         if (ln)
 889                                 node_free_immediate(net, ln);
 890                         return ERR_PTR(-ENOMEM);
 891                 }
 892
 893                 /*
 894                  * new intermediate node.
 895                  * RTN_RTINFO will
 896                  * be off since that an address that chooses one of
 897                  * the branches would not match less specific routes
 898                  * in the other branch
 899                  */
 900
 901                 in->fn_bit = bit;
 902
 903                 RCU_INIT_POINTER(in->parent, pn);
 904                 in->leaf = fn->leaf;
 905                 fib6_info_hold(rcu_dereference_protected(in->leaf,
 906                                 lockdep_is_held(&table->tb6_lock)));
 907
 908                 /* update parent pointer */
 909                 if (dir)
 910                         rcu_assign_pointer(pn->right, in);
 911                 else
 912                         rcu_assign_pointer(pn->left, in);
 913
 914                 ln->fn_bit = plen;
 915
 916                 RCU_INIT_POINTER(ln->parent, in);
 917                 rcu_assign_pointer(fn->parent, in);
 918
 919                 if (addr_bit_set(addr, bit)) {
 920                         rcu_assign_pointer(in->right, ln);
 921                         rcu_assign_pointer(in->left, fn);
 922                 } else {
 923                         rcu_assign_pointer(in->left, ln);
 924                         rcu_assign_pointer(in->right, fn);
 925                 }
 926         } else { /* plen <= bit */
 927
 928                 /*
 929                  *              (new leaf node)[ln]
 930                  *                /        \
 931                  *           (old node)[fn] NULL
 932                  */
 933
 934                 ln = node_alloc(net);
 935
 936                 if (!ln)
 937                         return ERR_PTR(-ENOMEM);
 938
 939                 ln->fn_bit = plen;
 940
 941                 RCU_INIT_POINTER(ln->parent, pn);
 942
 943                 if (addr_bit_set(&key->addr, plen))
 944                         RCU_INIT_POINTER(ln->right, fn);
 945                 else
 946                         RCU_INIT_POINTER(ln->left, fn);
 947
 948                 rcu_assign_pointer(fn->parent, ln);
 949
 950                 if (dir)
 951                         rcu_assign_pointer(pn->right, ln);
 952                 else
 953                         rcu_assign_pointer(pn->left, ln);
 954         }
 955         return ln;
 956 }
 957
 958 static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh,
 959                                   const struct fib6_info *match,
 960                                   const struct fib6_table *table)
 961 {
 962         int cpu;
 963
 964         if (!fib6_nh->rt6i_pcpu)
 965                 return;
 966
 967         /* release the reference to this fib entry from
 968          * all of its cached pcpu routes
 969          */
 970         for_each_possible_cpu(cpu) {
 971                 struct rt6_info **ppcpu_rt;
 972                 struct rt6_info *pcpu_rt;
 973
 974                 ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
 975                 pcpu_rt = *ppcpu_rt;
 976
 977                 /* only dropping the 'from' reference if the cached route
 978                  * is using 'match'. The cached pcpu_rt->from only changes
 979                  * from a fib6_info to NULL (ip6_dst_destroy); it can never
 980                  * change from one fib6_info reference to another
 981                  */
 982                 if (pcpu_rt && rcu_access_pointer(pcpu_rt->from) == match) {
 983                         struct fib6_info *from;
 984
 985                         from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
 986                         fib6_info_release(from);
 987                 }
 988         }
 989 }
 990
 991 struct fib6_nh_pcpu_arg {
 992         struct fib6_info        *from;
 993         const struct fib6_table *table;
 994 };
 995
 996 static int fib6_nh_drop_pcpu_from(struct fib6_nh *nh, void *_arg)
 997 {
 998         struct fib6_nh_pcpu_arg *arg = _arg;
 999
1000         __fib6_drop_pcpu_from(nh, arg->from, arg->table);
1001         return 0;
1002 }
1003
1004 static void fib6_drop_pcpu_from(struct fib6_info *f6i,
1005                                 const struct fib6_table *table)
1006 {
1007         /* Make sure rt6_make_pcpu_route() wont add other percpu routes
1008          * while we are cleaning them here.
1009          */
1010         f6i->fib6_destroying = 1;
1011         mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
1012
1013         if (f6i->nh) {
1014                 struct fib6_nh_pcpu_arg arg = {
1015                         .from = f6i,
1016                         .table = table
1017                 };
1018
1019                 nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_drop_pcpu_from,
1020                                          &arg);
1021         } else {
1022                 struct fib6_nh *fib6_nh;
1023
1024                 fib6_nh = f6i->fib6_nh;
1025                 __fib6_drop_pcpu_from(fib6_nh, f6i, table);
1026         }
1027 }
1028
1029 static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn,
1030                           struct net *net)
1031 {
1032         struct fib6_table *table = rt->fib6_table;
1033
1034         /* Flush all cached dst in exception table */
1035         rt6_flush_exceptions(rt);
1036         fib6_drop_pcpu_from(rt, table);
1037
1038         if (rt->nh && !list_empty(&rt->nh_list))
1039                 list_del_init(&rt->nh_list);
1040
1041         if (refcount_read(&rt->fib6_ref) != 1) {
1042                 /* This route is used as dummy address holder in some split
1043                  * nodes. It is not leaked, but it still holds other resources,
1044                  * which must be released in time. So, scan ascendant nodes
1045                  * and replace dummy references to this route with references
1046                  * to still alive ones.
1047                  */
1048                 while (fn) {
1049                         struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
1050                                             lockdep_is_held(&table->tb6_lock));
1051                         struct fib6_info *new_leaf;
1052                         if (!(fn->fn_flags & RTN_RTINFO) && leaf == rt) {
1053                                 new_leaf = fib6_find_prefix(net, table, fn);
1054                                 fib6_info_hold(new_leaf);
1055
1056                                 rcu_assign_pointer(fn->leaf, new_leaf);
1057                                 fib6_info_release(rt);
1058                         }
1059                         fn = rcu_dereference_protected(fn->parent,
1060                                     lockdep_is_held(&table->tb6_lock));
1061                 }
1062         }
1063
1064         fib6_clean_expires_locked(rt);
1065 }
1066
1067 /*
1068  *      Insert routing information in a node.
1069  */
1070
1071 static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
1072                             struct nl_info *info,
1073                             struct netlink_ext_ack *extack)
1074 {
1075         struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
1076                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1077         struct fib6_info *iter = NULL;
1078         struct fib6_info __rcu **ins;
1079         struct fib6_info __rcu **fallback_ins = NULL;
1080         int replace = (info->nlh &&
1081                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
1082         int add = (!info->nlh ||
1083                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
1084         int found = 0;
1085         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
1086         bool notify_sibling_rt = false;
1087         u16 nlflags = NLM_F_EXCL;
1088         int err;
1089
1090         if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))
1091                 nlflags |= NLM_F_APPEND;
1092
1093         ins = &fn->leaf;
1094
1095         for (iter = leaf; iter;
1096              iter = rcu_dereference_protected(iter->fib6_next,
1097                                 lockdep_is_held(&rt->fib6_table->tb6_lock))) {
1098                 /*
1099                  *      Search for duplicates
1100                  */
1101
1102                 if (iter->fib6_metric == rt->fib6_metric) {
1103                         /*
1104                          *      Same priority level
1105                          */
1106                         if (info->nlh &&
1107                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
1108                                 return -EEXIST;
1109
1110                         nlflags &= ~NLM_F_EXCL;
1111                         if (replace) {
1112                                 if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
1113                                         found++;
1114                                         break;
1115                                 }
1116                                 fallback_ins = fallback_ins ?: ins;
1117                                 goto next_iter;
1118                         }
1119
1120                         if (rt6_duplicate_nexthop(iter, rt)) {
1121                                 if (rt->fib6_nsiblings)
1122                                         rt->fib6_nsiblings = 0;
1123                                 if (!(iter->fib6_flags & RTF_EXPIRES))
1124                                         return -EEXIST;
1125                                 if (!(rt->fib6_flags & RTF_EXPIRES))
1126                                         fib6_clean_expires_locked(iter);
1127                                 else
1128                                         fib6_set_expires_locked(iter,
1129                                                                 rt->expires);
1130
1131                                 if (rt->fib6_pmtu)
1132                                         fib6_metric_set(iter, RTAX_MTU,
1133                                                         rt->fib6_pmtu);
1134                                 return -EEXIST;
1135                         }
1136                         /* If we have the same destination and the same metric,
1137                          * but not the same gateway, then the route we try to
1138                          * add is sibling to this route, increment our counter
1139                          * of siblings, and later we will add our route to the
1140                          * list.
1141                          * Only static routes (which don't have flag
1142                          * RTF_EXPIRES) are used for ECMPv6.
1143                          *
1144                          * To avoid long list, we only had siblings if the
1145                          * route have a gateway.
1146                          */
1147                         if (rt_can_ecmp &&
1148                             rt6_qualify_for_ecmp(iter))
1149                                 rt->fib6_nsiblings++;
1150                 }
1151
1152                 if (iter->fib6_metric > rt->fib6_metric)
1153                         break;
1154
1155 next_iter:
1156                 ins = &iter->fib6_next;
1157         }
1158
1159         if (fallback_ins && !found) {
1160                 /* No matching route with same ecmp-able-ness found, replace
1161                  * first matching route
1162                  */
1163                 ins = fallback_ins;
1164                 iter = rcu_dereference_protected(*ins,
1165                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1166                 found++;
1167         }
1168
1169         /* Reset round-robin state, if necessary */
1170         if (ins == &fn->leaf)
1171                 fn->rr_ptr = NULL;
1172
1173         /* Link this route to others same route. */
1174         if (rt->fib6_nsiblings) {
1175                 unsigned int fib6_nsiblings;
1176                 struct fib6_info *sibling, *temp_sibling;
1177
1178                 /* Find the first route that have the same metric */
1179                 sibling = leaf;
1180                 notify_sibling_rt = true;
1181                 while (sibling) {
1182                         if (sibling->fib6_metric == rt->fib6_metric &&
1183                             rt6_qualify_for_ecmp(sibling)) {
1184                                 list_add_tail(&rt->fib6_siblings,
1185                                               &sibling->fib6_siblings);
1186                                 break;
1187                         }
1188                         sibling = rcu_dereference_protected(sibling->fib6_next,
1189                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1190                         notify_sibling_rt = false;
1191                 }
1192                 /* For each sibling in the list, increment the counter of
1193                  * siblings. BUG() if counters does not match, list of siblings
1194                  * is broken!
1195                  */
1196                 fib6_nsiblings = 0;
1197                 list_for_each_entry_safe(sibling, temp_sibling,
1198                                          &rt->fib6_siblings, fib6_siblings) {
1199                         sibling->fib6_nsiblings++;
1200                         BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings);
1201                         fib6_nsiblings++;
1202                 }
1203                 BUG_ON(fib6_nsiblings != rt->fib6_nsiblings);
1204                 rt6_multipath_rebalance(temp_sibling);
1205         }
1206
1207         /*
1208          *      insert node
1209          */
1210         if (!replace) {
1211                 if (!add)
1212                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
1213
1214 add:
1215                 nlflags |= NLM_F_CREATE;
1216
1217                 /* The route should only be notified if it is the first
1218                  * route in the node or if it is added as a sibling
1219                  * route to the first route in the node.
1220                  */
1221                 if (!info->skip_notify_kernel &&
1222                     (notify_sibling_rt || ins == &fn->leaf)) {
1223                         enum fib_event_type fib_event;
1224
1225                         if (notify_sibling_rt)
1226                                 fib_event = FIB_EVENT_ENTRY_APPEND;
1227                         else
1228                                 fib_event = FIB_EVENT_ENTRY_REPLACE;
1229                         err = call_fib6_entry_notifiers(info->nl_net,
1230                                                         fib_event, rt,
1231                                                         extack);
1232                         if (err) {
1233                                 struct fib6_info *sibling, *next_sibling;
1234
1235                                 /* If the route has siblings, then it first
1236                                  * needs to be unlinked from them.
1237                                  */
1238                                 if (!rt->fib6_nsiblings)
1239                                         return err;
1240
1241                                 list_for_each_entry_safe(sibling, next_sibling,
1242                                                          &rt->fib6_siblings,
1243                                                          fib6_siblings)
1244                                         sibling->fib6_nsiblings--;
1245                                 rt->fib6_nsiblings = 0;
1246                                 list_del_init(&rt->fib6_siblings);
1247                                 rt6_multipath_rebalance(next_sibling);
1248                                 return err;
1249                         }
1250                 }
1251
1252                 rcu_assign_pointer(rt->fib6_next, iter);
1253                 fib6_info_hold(rt);
1254                 rcu_assign_pointer(rt->fib6_node, fn);
1255                 rcu_assign_pointer(*ins, rt);
1256                 if (!info->skip_notify)
1257                         inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
1258                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
1259
1260                 if (!(fn->fn_flags & RTN_RTINFO)) {
1261                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1262                         fn->fn_flags |= RTN_RTINFO;
1263                 }
1264
1265         } else {
1266                 int nsiblings;
1267
1268                 if (!found) {
1269                         if (add)
1270                                 goto add;
1271                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
1272                         return -ENOENT;
1273                 }
1274
1275                 if (!info->skip_notify_kernel && ins == &fn->leaf) {
1276                         err = call_fib6_entry_notifiers(info->nl_net,
1277                                                         FIB_EVENT_ENTRY_REPLACE,
1278                                                         rt, extack);
1279                         if (err)
1280                                 return err;
1281                 }
1282
1283                 fib6_info_hold(rt);
1284                 rcu_assign_pointer(rt->fib6_node, fn);
1285                 rt->fib6_next = iter->fib6_next;
1286                 rcu_assign_pointer(*ins, rt);
1287                 if (!info->skip_notify)
1288                         inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
1289                 if (!(fn->fn_flags & RTN_RTINFO)) {
1290                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1291                         fn->fn_flags |= RTN_RTINFO;
1292                 }
1293                 nsiblings = iter->fib6_nsiblings;
1294                 iter->fib6_node = NULL;
1295                 fib6_purge_rt(iter, fn, info->nl_net);
1296                 if (rcu_access_pointer(fn->rr_ptr) == iter)
1297                         fn->rr_ptr = NULL;
1298                 fib6_info_release(iter);
1299
1300                 if (nsiblings) {
1301                         /* Replacing an ECMP route, remove all siblings */
1302                         ins = &rt->fib6_next;
1303                         iter = rcu_dereference_protected(*ins,
1304                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1305                         while (iter) {
1306                                 if (iter->fib6_metric > rt->fib6_metric)
1307                                         break;
1308                                 if (rt6_qualify_for_ecmp(iter)) {
1309                                         *ins = iter->fib6_next;
1310                                         iter->fib6_node = NULL;
1311                                         fib6_purge_rt(iter, fn, info->nl_net);
1312                                         if (rcu_access_pointer(fn->rr_ptr) == iter)
1313                                                 fn->rr_ptr = NULL;
1314                                         fib6_info_release(iter);
1315                                         nsiblings--;
1316                                         info->nl_net->ipv6.rt6_stats->fib_rt_entries--;
1317                                 } else {
1318                                         ins = &iter->fib6_next;
1319                                 }
1320                                 iter = rcu_dereference_protected(*ins,
1321                                         lockdep_is_held(&rt->fib6_table->tb6_lock));
1322                         }
1323                         WARN_ON(nsiblings != 0);
1324                 }
1325         }
1326
1327         return 0;
1328 }
1329
1330 static void fib6_start_gc(struct net *net, struct fib6_info *rt)
1331 {
1332         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
1333             (rt->fib6_flags & RTF_EXPIRES))
1334                 mod_timer(&net->ipv6.ip6_fib_timer,
1335                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1336 }
1337
1338 void fib6_force_start_gc(struct net *net)
1339 {
1340         if (!timer_pending(&net->ipv6.ip6_fib_timer))
1341                 mod_timer(&net->ipv6.ip6_fib_timer,
1342                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1343 }
1344
1345 static void __fib6_update_sernum_upto_root(struct fib6_info *rt,
1346                                            int sernum)
1347 {
1348         struct fib6_node *fn = rcu_dereference_protected(rt->fib6_node,
1349                                 lockdep_is_held(&rt->fib6_table->tb6_lock));
1350
1351         /* paired with smp_rmb() in fib6_get_cookie_safe() */
1352         smp_wmb();
1353         while (fn) {
1354                 WRITE_ONCE(fn->fn_sernum, sernum);
1355                 fn = rcu_dereference_protected(fn->parent,
1356                                 lockdep_is_held(&rt->fib6_table->tb6_lock));
1357         }
1358 }
1359
1360 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt)
1361 {
1362         __fib6_update_sernum_upto_root(rt, fib6_new_sernum(net));
1363 }
1364
1365 /* allow ipv4 to update sernum via ipv6_stub */
1366 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i)
1367 {
1368         spin_lock_bh(&f6i->fib6_table->tb6_lock);
1369         fib6_update_sernum_upto_root(net, f6i);
1370         spin_unlock_bh(&f6i->fib6_table->tb6_lock);
1371 }
1372
1373 /*
1374  *      Add routing information to the routing tree.
1375  *      <destination addr>/<source addr>
1376  *      with source addr info in sub-trees
1377  *      Need to own table->tb6_lock
1378  */
1379
1380 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
1381              struct nl_info *info, struct netlink_ext_ack *extack)
1382 {
1383         struct fib6_table *table = rt->fib6_table;
1384         struct fib6_node *fn, *pn = NULL;
1385         int err = -ENOMEM;
1386         int allow_create = 1;
1387         int replace_required = 0;
1388
1389         if (info->nlh) {
1390                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
1391                         allow_create = 0;
1392                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
1393                         replace_required = 1;
1394         }
1395         if (!allow_create && !replace_required)
1396                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
1397
1398         fn = fib6_add_1(info->nl_net, table, root,
1399                         &rt->fib6_dst.addr, rt->fib6_dst.plen,
1400                         offsetof(struct fib6_info, fib6_dst), allow_create,
1401                         replace_required, extack);
1402         if (IS_ERR(fn)) {
1403                 err = PTR_ERR(fn);
1404                 fn = NULL;
1405                 goto out;
1406         }
1407
1408         pn = fn;
1409
1410 #ifdef CONFIG_IPV6_SUBTREES
1411         if (rt->fib6_src.plen) {
1412                 struct fib6_node *sn;
1413
1414                 if (!rcu_access_pointer(fn->subtree)) {
1415                         struct fib6_node *sfn;
1416
1417                         /*
1418                          * Create subtree.
1419                          *
1420                          *              fn[main tree]
1421                          *              |
1422                          *              sfn[subtree root]
1423                          *                 \
1424                          *                  sn[new leaf node]
1425                          */
1426
1427                         /* Create subtree root node */
1428                         sfn = node_alloc(info->nl_net);
1429                         if (!sfn)
1430                                 goto failure;
1431
1432                         fib6_info_hold(info->nl_net->ipv6.fib6_null_entry);
1433                         rcu_assign_pointer(sfn->leaf,
1434                                            info->nl_net->ipv6.fib6_null_entry);
1435                         sfn->fn_flags = RTN_ROOT;
1436
1437                         /* Now add the first leaf node to new subtree */
1438
1439                         sn = fib6_add_1(info->nl_net, table, sfn,
1440                                         &rt->fib6_src.addr, rt->fib6_src.plen,
1441                                         offsetof(struct fib6_info, fib6_src),
1442                                         allow_create, replace_required, extack);
1443
1444                         if (IS_ERR(sn)) {
1445                                 /* If it is failed, discard just allocated
1446                                    root, and then (in failure) stale node
1447                                    in main tree.
1448                                  */
1449                                 node_free_immediate(info->nl_net, sfn);
1450                                 err = PTR_ERR(sn);
1451                                 goto failure;
1452                         }
1453
1454                         /* Now link new subtree to main tree */
1455                         rcu_assign_pointer(sfn->parent, fn);
1456                         rcu_assign_pointer(fn->subtree, sfn);
1457                 } else {
1458                         sn = fib6_add_1(info->nl_net, table, FIB6_SUBTREE(fn),
1459                                         &rt->fib6_src.addr, rt->fib6_src.plen,
1460                                         offsetof(struct fib6_info, fib6_src),
1461                                         allow_create, replace_required, extack);
1462
1463                         if (IS_ERR(sn)) {
1464                                 err = PTR_ERR(sn);
1465                                 goto failure;
1466                         }
1467                 }
1468
1469                 if (!rcu_access_pointer(fn->leaf)) {
1470                         if (fn->fn_flags & RTN_TL_ROOT) {
1471                                 /* put back null_entry for root node */
1472                                 rcu_assign_pointer(fn->leaf,
1473                                             info->nl_net->ipv6.fib6_null_entry);
1474                         } else {
1475                                 fib6_info_hold(rt);
1476                                 rcu_assign_pointer(fn->leaf, rt);
1477                         }
1478                 }
1479                 fn = sn;
1480         }
1481 #endif
1482
1483         err = fib6_add_rt2node(fn, rt, info, extack);
1484         if (!err) {
1485                 if (rt->nh)
1486                         list_add(&rt->nh_list, &rt->nh->f6i_list);
1487                 __fib6_update_sernum_upto_root(rt, fib6_new_sernum(info->nl_net));
1488
1489                 if (fib6_has_expires(rt))
1490                         hlist_add_head(&rt->gc_link, &table->tb6_gc_hlist);
1491
1492                 fib6_start_gc(info->nl_net, rt);
1493         }
1494
1495 out:
1496         if (err) {
1497 #ifdef CONFIG_IPV6_SUBTREES
1498                 /*
1499                  * If fib6_add_1 has cleared the old leaf pointer in the
1500                  * super-tree leaf node we have to find a new one for it.
1501                  */
1502                 if (pn != fn) {
1503                         struct fib6_info *pn_leaf =
1504                                 rcu_dereference_protected(pn->leaf,
1505                                     lockdep_is_held(&table->tb6_lock));
1506                         if (pn_leaf == rt) {
1507                                 pn_leaf = NULL;
1508                                 RCU_INIT_POINTER(pn->leaf, NULL);
1509                                 fib6_info_release(rt);
1510                         }
1511                         if (!pn_leaf && !(pn->fn_flags & RTN_RTINFO)) {
1512                                 pn_leaf = fib6_find_prefix(info->nl_net, table,
1513                                                            pn);
1514 #if RT6_DEBUG >= 2
1515                                 if (!pn_leaf) {
1516                                         WARN_ON(!pn_leaf);
1517                                         pn_leaf =
1518                                             info->nl_net->ipv6.fib6_null_entry;
1519                                 }
1520 #endif
1521                                 fib6_info_hold(pn_leaf);
1522                                 rcu_assign_pointer(pn->leaf, pn_leaf);
1523                         }
1524                 }
1525 #endif
1526                 goto failure;
1527         } else if (fib6_requires_src(rt)) {
1528                 fib6_routes_require_src_inc(info->nl_net);
1529         }
1530         return err;
1531
1532 failure:
1533         /* fn->leaf could be NULL and fib6_repair_tree() needs to be called if:
1534          * 1. fn is an intermediate node and we failed to add the new
1535          * route to it in both subtree creation failure and fib6_add_rt2node()
1536          * failure case.
1537          * 2. fn is the root node in the table and we fail to add the first
1538          * default route to it.
1539          */
1540         if (fn &&
1541             (!(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)) ||
1542              (fn->fn_flags & RTN_TL_ROOT &&
1543               !rcu_access_pointer(fn->leaf))))
1544                 fib6_repair_tree(info->nl_net, table, fn);
1545         return err;
1546 }
1547
1548 /*
1549  *      Routing tree lookup
1550  *
1551  */
1552
1553 struct lookup_args {
1554         int                     offset;         /* key offset on fib6_info */
1555         const struct in6_addr   *addr;          /* search key                   */
1556 };
1557
1558 static struct fib6_node *fib6_node_lookup_1(struct fib6_node *root,
1559                                             struct lookup_args *args)
1560 {
1561         struct fib6_node *fn;
1562         __be32 dir;
1563
1564         if (unlikely(args->offset == 0))
1565                 return NULL;
1566
1567         /*
1568          *      Descend on a tree
1569          */
1570
1571         fn = root;
1572
1573         for (;;) {
1574                 struct fib6_node *next;
1575
1576                 dir = addr_bit_set(args->addr, fn->fn_bit);
1577
1578                 next = dir ? rcu_dereference(fn->right) :
1579                              rcu_dereference(fn->left);
1580
1581                 if (next) {
1582                         fn = next;
1583                         continue;
1584                 }
1585                 break;
1586         }
1587
1588         while (fn) {
1589                 struct fib6_node *subtree = FIB6_SUBTREE(fn);
1590
1591                 if (subtree || fn->fn_flags & RTN_RTINFO) {
1592                         struct fib6_info *leaf = rcu_dereference(fn->leaf);
1593                         struct rt6key *key;
1594
1595                         if (!leaf)
1596                                 goto backtrack;
1597
1598                         key = (struct rt6key *) ((u8 *)leaf + args->offset);
1599
1600                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1601 #ifdef CONFIG_IPV6_SUBTREES
1602                                 if (subtree) {
1603                                         struct fib6_node *sfn;
1604                                         sfn = fib6_node_lookup_1(subtree,
1605                                                                  args + 1);
1606                                         if (!sfn)
1607                                                 goto backtrack;
1608                                         fn = sfn;
1609                                 }
1610 #endif
1611                                 if (fn->fn_flags & RTN_RTINFO)
1612                                         return fn;
1613                         }
1614                 }
1615 backtrack:
1616                 if (fn->fn_flags & RTN_ROOT)
1617                         break;
1618
1619                 fn = rcu_dereference(fn->parent);
1620         }
1621
1622         return NULL;
1623 }
1624
1625 /* called with rcu_read_lock() held
1626  */
1627 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
1628                                    const struct in6_addr *daddr,
1629                                    const struct in6_addr *saddr)
1630 {
1631         struct fib6_node *fn;
1632         struct lookup_args args[] = {
1633                 {
1634                         .offset = offsetof(struct fib6_info, fib6_dst),
1635                         .addr = daddr,
1636                 },
1637 #ifdef CONFIG_IPV6_SUBTREES
1638                 {
1639                         .offset = offsetof(struct fib6_info, fib6_src),
1640                         .addr = saddr,
1641                 },
1642 #endif
1643                 {
1644                         .offset = 0,    /* sentinel */
1645                 }
1646         };
1647
1648         fn = fib6_node_lookup_1(root, daddr ? args : args + 1);
1649         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1650                 fn = root;
1651
1652         return fn;
1653 }
1654
1655 /*
1656  *      Get node with specified destination prefix (and source prefix,
1657  *      if subtrees are used)
1658  *      exact_match == true means we try to find fn with exact match of
1659  *      the passed in prefix addr
1660  *      exact_match == false means we try to find fn with longest prefix
1661  *      match of the passed in prefix addr. This is useful for finding fn
1662  *      for cached route as it will be stored in the exception table under
1663  *      the node with longest prefix length.
1664  */
1665
1666
1667 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1668                                        const struct in6_addr *addr,
1669                                        int plen, int offset,
1670                                        bool exact_match)
1671 {
1672         struct fib6_node *fn, *prev = NULL;
1673
1674         for (fn = root; fn ; ) {
1675                 struct fib6_info *leaf = rcu_dereference(fn->leaf);
1676                 struct rt6key *key;
1677
1678                 /* This node is being deleted */
1679                 if (!leaf) {
1680                         if (plen <= fn->fn_bit)
1681                                 goto out;
1682                         else
1683                                 goto next;
1684                 }
1685
1686                 key = (struct rt6key *)((u8 *)leaf + offset);
1687
1688                 /*
1689                  *      Prefix match
1690                  */
1691                 if (plen < fn->fn_bit ||
1692                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1693                         goto out;
1694
1695                 if (plen == fn->fn_bit)
1696                         return fn;
1697
1698                 if (fn->fn_flags & RTN_RTINFO)
1699                         prev = fn;
1700
1701 next:
1702                 /*
1703                  *      We have more bits to go
1704                  */
1705                 if (addr_bit_set(addr, fn->fn_bit))
1706                         fn = rcu_dereference(fn->right);
1707                 else
1708                         fn = rcu_dereference(fn->left);
1709         }
1710 out:
1711         if (exact_match)
1712                 return NULL;
1713         else
1714                 return prev;
1715 }
1716
1717 struct fib6_node *fib6_locate(struct fib6_node *root,
1718                               const struct in6_addr *daddr, int dst_len,
1719                               const struct in6_addr *saddr, int src_len,
1720                               bool exact_match)
1721 {
1722         struct fib6_node *fn;
1723
1724         fn = fib6_locate_1(root, daddr, dst_len,
1725                            offsetof(struct fib6_info, fib6_dst),
1726                            exact_match);
1727
1728 #ifdef CONFIG_IPV6_SUBTREES
1729         if (src_len) {
1730                 WARN_ON(saddr == NULL);
1731                 if (fn) {
1732                         struct fib6_node *subtree = FIB6_SUBTREE(fn);
1733
1734                         if (subtree) {
1735                                 fn = fib6_locate_1(subtree, saddr, src_len,
1736                                            offsetof(struct fib6_info, fib6_src),
1737                                            exact_match);
1738                         }
1739                 }
1740         }
1741 #endif
1742
1743         if (fn && fn->fn_flags & RTN_RTINFO)
1744                 return fn;
1745
1746         return NULL;
1747 }
1748
1749
1750 /*
1751  *      Deletion
1752  *
1753  */
1754
1755 static struct fib6_info *fib6_find_prefix(struct net *net,
1756                                          struct fib6_table *table,
1757                                          struct fib6_node *fn)
1758 {
1759         struct fib6_node *child_left, *child_right;
1760
1761         if (fn->fn_flags & RTN_ROOT)
1762                 return net->ipv6.fib6_null_entry;
1763
1764         while (fn) {
1765                 child_left = rcu_dereference_protected(fn->left,
1766                                     lockdep_is_held(&table->tb6_lock));
1767                 child_right = rcu_dereference_protected(fn->right,
1768                                     lockdep_is_held(&table->tb6_lock));
1769                 if (child_left)
1770                         return rcu_dereference_protected(child_left->leaf,
1771                                         lockdep_is_held(&table->tb6_lock));
1772                 if (child_right)
1773                         return rcu_dereference_protected(child_right->leaf,
1774                                         lockdep_is_held(&table->tb6_lock));
1775
1776                 fn = FIB6_SUBTREE(fn);
1777         }
1778         return NULL;
1779 }
1780
1781 /*
1782  *      Called to trim the tree of intermediate nodes when possible. "fn"
1783  *      is the node we want to try and remove.
1784  *      Need to own table->tb6_lock
1785  */
1786
1787 static struct fib6_node *fib6_repair_tree(struct net *net,
1788                                           struct fib6_table *table,
1789                                           struct fib6_node *fn)
1790 {
1791         int children;
1792         int nstate;
1793         struct fib6_node *child;
1794         struct fib6_walker *w;
1795         int iter = 0;
1796
1797         /* Set fn->leaf to null_entry for root node. */
1798         if (fn->fn_flags & RTN_TL_ROOT) {
1799                 rcu_assign_pointer(fn->leaf, net->ipv6.fib6_null_entry);
1800                 return fn;
1801         }
1802
1803         for (;;) {
1804                 struct fib6_node *fn_r = rcu_dereference_protected(fn->right,
1805                                             lockdep_is_held(&table->tb6_lock));
1806                 struct fib6_node *fn_l = rcu_dereference_protected(fn->left,
1807                                             lockdep_is_held(&table->tb6_lock));
1808                 struct fib6_node *pn = rcu_dereference_protected(fn->parent,
1809                                             lockdep_is_held(&table->tb6_lock));
1810                 struct fib6_node *pn_r = rcu_dereference_protected(pn->right,
1811                                             lockdep_is_held(&table->tb6_lock));
1812                 struct fib6_node *pn_l = rcu_dereference_protected(pn->left,
1813                                             lockdep_is_held(&table->tb6_lock));
1814                 struct fib6_info *fn_leaf = rcu_dereference_protected(fn->leaf,
1815                                             lockdep_is_held(&table->tb6_lock));
1816                 struct fib6_info *pn_leaf = rcu_dereference_protected(pn->leaf,
1817                                             lockdep_is_held(&table->tb6_lock));
1818                 struct fib6_info *new_fn_leaf;
1819
1820                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1821                 iter++;
1822
1823                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1824                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1825                 WARN_ON(fn_leaf);
1826
1827                 children = 0;
1828                 child = NULL;
1829                 if (fn_r) {
1830                         child = fn_r;
1831                         children |= 1;
1832                 }
1833                 if (fn_l) {
1834                         child = fn_l;
1835                         children |= 2;
1836                 }
1837
1838                 if (children == 3 || FIB6_SUBTREE(fn)
1839 #ifdef CONFIG_IPV6_SUBTREES
1840                     /* Subtree root (i.e. fn) may have one child */
1841                     || (children && fn->fn_flags & RTN_ROOT)
1842 #endif
1843                     ) {
1844                         new_fn_leaf = fib6_find_prefix(net, table, fn);
1845 #if RT6_DEBUG >= 2
1846                         if (!new_fn_leaf) {
1847                                 WARN_ON(!new_fn_leaf);
1848                                 new_fn_leaf = net->ipv6.fib6_null_entry;
1849                         }
1850 #endif
1851                         fib6_info_hold(new_fn_leaf);
1852                         rcu_assign_pointer(fn->leaf, new_fn_leaf);
1853                         return pn;
1854                 }
1855
1856 #ifdef CONFIG_IPV6_SUBTREES
1857                 if (FIB6_SUBTREE(pn) == fn) {
1858                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1859                         RCU_INIT_POINTER(pn->subtree, NULL);
1860                         nstate = FWS_L;
1861                 } else {
1862                         WARN_ON(fn->fn_flags & RTN_ROOT);
1863 #endif
1864                         if (pn_r == fn)
1865                                 rcu_assign_pointer(pn->right, child);
1866                         else if (pn_l == fn)
1867                                 rcu_assign_pointer(pn->left, child);
1868 #if RT6_DEBUG >= 2
1869                         else
1870                                 WARN_ON(1);
1871 #endif
1872                         if (child)
1873                                 rcu_assign_pointer(child->parent, pn);
1874                         nstate = FWS_R;
1875 #ifdef CONFIG_IPV6_SUBTREES
1876                 }
1877 #endif
1878
1879                 read_lock(&net->ipv6.fib6_walker_lock);
1880                 FOR_WALKERS(net, w) {
1881                         if (!child) {
1882                                 if (w->node == fn) {
1883                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1884                                         w->node = pn;
1885                                         w->state = nstate;
1886                                 }
1887                         } else {
1888                                 if (w->node == fn) {
1889                                         w->node = child;
1890                                         if (children&2) {
1891                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1892                                                 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1893                                         } else {
1894                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1895                                                 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1896                                         }
1897                                 }
1898                         }
1899                 }
1900                 read_unlock(&net->ipv6.fib6_walker_lock);
1901
1902                 node_free(net, fn);
1903                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1904                         return pn;
1905
1906                 RCU_INIT_POINTER(pn->leaf, NULL);
1907                 fib6_info_release(pn_leaf);
1908                 fn = pn;
1909         }
1910 }
1911
1912 static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
1913                            struct fib6_info __rcu **rtp, struct nl_info *info)
1914 {
1915         struct fib6_info *leaf, *replace_rt = NULL;
1916         struct fib6_walker *w;
1917         struct fib6_info *rt = rcu_dereference_protected(*rtp,
1918                                     lockdep_is_held(&table->tb6_lock));
1919         struct net *net = info->nl_net;
1920         bool notify_del = false;
1921
1922         RT6_TRACE("fib6_del_route\n");
1923
1924         /* If the deleted route is the first in the node and it is not part of
1925          * a multipath route, then we need to replace it with the next route
1926          * in the node, if exists.
1927          */
1928         leaf = rcu_dereference_protected(fn->leaf,
1929                                          lockdep_is_held(&table->tb6_lock));
1930         if (leaf == rt && !rt->fib6_nsiblings) {
1931                 if (rcu_access_pointer(rt->fib6_next))
1932                         replace_rt = rcu_dereference_protected(rt->fib6_next,
1933                                             lockdep_is_held(&table->tb6_lock));
1934                 else
1935                         notify_del = true;
1936         }
1937
1938         /* Unlink it */
1939         *rtp = rt->fib6_next;
1940         rt->fib6_node = NULL;
1941         net->ipv6.rt6_stats->fib_rt_entries--;
1942         net->ipv6.rt6_stats->fib_discarded_routes++;
1943
1944         /* Reset round-robin state, if necessary */
1945         if (rcu_access_pointer(fn->rr_ptr) == rt)
1946                 fn->rr_ptr = NULL;
1947
1948         /* Remove this entry from other siblings */
1949         if (rt->fib6_nsiblings) {
1950                 struct fib6_info *sibling, *next_sibling;
1951
1952                 /* The route is deleted from a multipath route. If this
1953                  * multipath route is the first route in the node, then we need
1954                  * to emit a delete notification. Otherwise, we need to skip
1955                  * the notification.
1956                  */
1957                 if (rt->fib6_metric == leaf->fib6_metric &&
1958                     rt6_qualify_for_ecmp(leaf))
1959                         notify_del = true;
1960                 list_for_each_entry_safe(sibling, next_sibling,
1961                                          &rt->fib6_siblings, fib6_siblings)
1962                         sibling->fib6_nsiblings--;
1963                 rt->fib6_nsiblings = 0;
1964                 list_del_init(&rt->fib6_siblings);
1965                 rt6_multipath_rebalance(next_sibling);
1966         }
1967
1968         /* Adjust walkers */
1969         read_lock(&net->ipv6.fib6_walker_lock);
1970         FOR_WALKERS(net, w) {
1971                 if (w->state == FWS_C && w->leaf == rt) {
1972                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1973                         w->leaf = rcu_dereference_protected(rt->fib6_next,
1974                                             lockdep_is_held(&table->tb6_lock));
1975                         if (!w->leaf)
1976                                 w->state = FWS_U;
1977                 }
1978         }
1979         read_unlock(&net->ipv6.fib6_walker_lock);
1980
1981         /* If it was last route, call fib6_repair_tree() to:
1982          * 1. For root node, put back null_entry as how the table was created.
1983          * 2. For other nodes, expunge its radix tree node.
1984          */
1985         if (!rcu_access_pointer(fn->leaf)) {
1986                 if (!(fn->fn_flags & RTN_TL_ROOT)) {
1987                         fn->fn_flags &= ~RTN_RTINFO;
1988                         net->ipv6.rt6_stats->fib_route_nodes--;
1989                 }
1990                 fn = fib6_repair_tree(net, table, fn);
1991         }
1992
1993         fib6_purge_rt(rt, fn, net);
1994
1995         if (!info->skip_notify_kernel) {
1996                 if (notify_del)
1997                         call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
1998                                                   rt, NULL);
1999                 else if (replace_rt)
2000                         call_fib6_entry_notifiers_replace(net, replace_rt);
2001         }
2002         if (!info->skip_notify)
2003                 inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
2004
2005         fib6_info_release(rt);
2006 }
2007
2008 /* Need to own table->tb6_lock */
2009 int fib6_del(struct fib6_info *rt, struct nl_info *info)
2010 {
2011         struct net *net = info->nl_net;
2012         struct fib6_info __rcu **rtp;
2013         struct fib6_info __rcu **rtp_next;
2014         struct fib6_table *table;
2015         struct fib6_node *fn;
2016
2017         if (rt == net->ipv6.fib6_null_entry)
2018                 return -ENOENT;
2019
2020         table = rt->fib6_table;
2021         fn = rcu_dereference_protected(rt->fib6_node,
2022                                        lockdep_is_held(&table->tb6_lock));
2023         if (!fn)
2024                 return -ENOENT;
2025
2026         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
2027
2028         /*
2029          *      Walk the leaf entries looking for ourself
2030          */
2031
2032         for (rtp = &fn->leaf; *rtp; rtp = rtp_next) {
2033                 struct fib6_info *cur = rcu_dereference_protected(*rtp,
2034                                         lockdep_is_held(&table->tb6_lock));
2035                 if (rt == cur) {
2036                         if (fib6_requires_src(cur))
2037                                 fib6_routes_require_src_dec(info->nl_net);
2038                         fib6_del_route(table, fn, rtp, info);
2039                         return 0;
2040                 }
2041                 rtp_next = &cur->fib6_next;
2042         }
2043         return -ENOENT;
2044 }
2045
2046 /*
2047  *      Tree traversal function.
2048  *
2049  *      Certainly, it is not interrupt safe.
2050  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
2051  *      It means, that we can modify tree during walking
2052  *      and use this function for garbage collection, clone pruning,
2053  *      cleaning tree when a device goes down etc. etc.
2054  *
2055  *      It guarantees that every node will be traversed,
2056  *      and that it will be traversed only once.
2057  *
2058  *      Callback function w->func may return:
2059  *      0 -> continue walking.
2060  *      positive value -> walking is suspended (used by tree dumps,
2061  *      and probably by gc, if it will be split to several slices)
2062  *      negative value -> terminate walking.
2063  *
2064  *      The function itself returns:
2065  *      0   -> walk is complete.
2066  *      >0  -> walk is incomplete (i.e. suspended)
2067  *      <0  -> walk is terminated by an error.
2068  *
2069  *      This function is called with tb6_lock held.
2070  */
2071
2072 static int fib6_walk_continue(struct fib6_walker *w)
2073 {
2074         struct fib6_node *fn, *pn, *left, *right;
2075
2076         /* w->root should always be table->tb6_root */
2077         WARN_ON_ONCE(!(w->root->fn_flags & RTN_TL_ROOT));
2078
2079         for (;;) {
2080                 fn = w->node;
2081                 if (!fn)
2082                         return 0;
2083
2084                 switch (w->state) {
2085 #ifdef CONFIG_IPV6_SUBTREES
2086                 case FWS_S:
2087                         if (FIB6_SUBTREE(fn)) {
2088                                 w->node = FIB6_SUBTREE(fn);
2089                                 continue;
2090                         }
2091                         w->state = FWS_L;
2092                         fallthrough;
2093 #endif
2094                 case FWS_L:
2095                         left = rcu_dereference_protected(fn->left, 1);
2096                         if (left) {
2097                                 w->node = left;
2098                                 w->state = FWS_INIT;
2099                                 continue;
2100                         }
2101                         w->state = FWS_R;
2102                         fallthrough;
2103                 case FWS_R:
2104                         right = rcu_dereference_protected(fn->right, 1);
2105                         if (right) {
2106                                 w->node = right;
2107                                 w->state = FWS_INIT;
2108                                 continue;
2109                         }
2110                         w->state = FWS_C;
2111                         w->leaf = rcu_dereference_protected(fn->leaf, 1);
2112                         fallthrough;
2113                 case FWS_C:
2114                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
2115                                 int err;
2116
2117                                 if (w->skip) {
2118                                         w->skip--;
2119                                         goto skip;
2120                                 }
2121
2122                                 err = w->func(w);
2123                                 if (err)
2124                                         return err;
2125
2126                                 w->count++;
2127                                 continue;
2128                         }
2129 skip:
2130                         w->state = FWS_U;
2131                         fallthrough;
2132                 case FWS_U:
2133                         if (fn == w->root)
2134                                 return 0;
2135                         pn = rcu_dereference_protected(fn->parent, 1);
2136                         left = rcu_dereference_protected(pn->left, 1);
2137                         right = rcu_dereference_protected(pn->right, 1);
2138                         w->node = pn;
2139 #ifdef CONFIG_IPV6_SUBTREES
2140                         if (FIB6_SUBTREE(pn) == fn) {
2141                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
2142                                 w->state = FWS_L;
2143                                 continue;
2144                         }
2145 #endif
2146                         if (left == fn) {
2147                                 w->state = FWS_R;
2148                                 continue;
2149                         }
2150                         if (right == fn) {
2151                                 w->state = FWS_C;
2152                                 w->leaf = rcu_dereference_protected(w->node->leaf, 1);
2153                                 continue;
2154                         }
2155 #if RT6_DEBUG >= 2
2156                         WARN_ON(1);
2157 #endif
2158                 }
2159         }
2160 }
2161
2162 static int fib6_walk(struct net *net, struct fib6_walker *w)
2163 {
2164         int res;
2165
2166         w->state = FWS_INIT;
2167         w->node = w->root;
2168
2169         fib6_walker_link(net, w);
2170         res = fib6_walk_continue(w);
2171         if (res <= 0)
2172                 fib6_walker_unlink(net, w);
2173         return res;
2174 }
2175
2176 static int fib6_clean_node(struct fib6_walker *w)
2177 {
2178         int res;
2179         struct fib6_info *rt;
2180         struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
2181         struct nl_info info = {
2182                 .nl_net = c->net,
2183                 .skip_notify = c->skip_notify,
2184         };
2185
2186         if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
2187             READ_ONCE(w->node->fn_sernum) != c->sernum)
2188                 WRITE_ONCE(w->node->fn_sernum, c->sernum);
2189
2190         if (!c->func) {
2191                 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
2192                 w->leaf = NULL;
2193                 return 0;
2194         }
2195
2196         for_each_fib6_walker_rt(w) {
2197                 res = c->func(rt, c->arg);
2198                 if (res == -1) {
2199                         w->leaf = rt;
2200                         res = fib6_del(rt, &info);
2201                         if (res) {
2202 #if RT6_DEBUG >= 2
2203                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
2204                                          __func__, rt,
2205                                          rcu_access_pointer(rt->fib6_node),
2206                                          res);
2207 #endif
2208                                 continue;
2209                         }
2210                         return 0;
2211                 } else if (res == -2) {
2212                         if (WARN_ON(!rt->fib6_nsiblings))
2213                                 continue;
2214                         rt = list_last_entry(&rt->fib6_siblings,
2215                                              struct fib6_info, fib6_siblings);
2216                         continue;
2217                 }
2218                 WARN_ON(res != 0);
2219         }
2220         w->leaf = rt;
2221         return 0;
2222 }
2223
2224 /*
2225  *      Convenient frontend to tree walker.
2226  *
2227  *      func is called on each route.
2228  *              It may return -2 -> skip multipath route.
2229  *                            -1 -> delete this route.
2230  *                            0  -> continue walking
2231  */
2232
2233 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
2234                             int (*func)(struct fib6_info *, void *arg),
2235                             int sernum, void *arg, bool skip_notify)
2236 {
2237         struct fib6_cleaner c;
2238
2239         c.w.root = root;
2240         c.w.func = fib6_clean_node;
2241         c.w.count = 0;
2242         c.w.skip = 0;
2243         c.w.skip_in_node = 0;
2244         c.func = func;
2245         c.sernum = sernum;
2246         c.arg = arg;
2247         c.net = net;
2248         c.skip_notify = skip_notify;
2249
2250         fib6_walk(net, &c.w);
2251 }
2252
2253 static void __fib6_clean_all(struct net *net,
2254                              int (*func)(struct fib6_info *, void *),
2255                              int sernum, void *arg, bool skip_notify)
2256 {
2257         struct fib6_table *table;
2258         struct hlist_head *head;
2259         unsigned int h;
2260
2261         rcu_read_lock();
2262         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
2263                 head = &net->ipv6.fib_table_hash[h];
2264                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
2265                         spin_lock_bh(&table->tb6_lock);
2266                         fib6_clean_tree(net, &table->tb6_root,
2267                                         func, sernum, arg, skip_notify);
2268                         spin_unlock_bh(&table->tb6_lock);
2269                 }
2270         }
2271         rcu_read_unlock();
2272 }
2273
2274 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *),
2275                     void *arg)
2276 {
2277         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, false);
2278 }
2279
2280 void fib6_clean_all_skip_notify(struct net *net,
2281                                 int (*func)(struct fib6_info *, void *),
2282                                 void *arg)
2283 {
2284         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, true);
2285 }
2286
2287 static void fib6_flush_trees(struct net *net)
2288 {
2289         int new_sernum = fib6_new_sernum(net);
2290
2291         __fib6_clean_all(net, NULL, new_sernum, NULL, false);
2292 }
2293
2294 /*
2295  *      Garbage collection
2296  */
2297
2298 static int fib6_age(struct fib6_info *rt, struct fib6_gc_args *gc_args)
2299 {
2300         unsigned long now = jiffies;
2301
2302         /*
2303          *      check addrconf expiration here.
2304          *      Routes are expired even if they are in use.
2305          */
2306
2307         if (fib6_has_expires(rt) && rt->expires) {
2308                 if (time_after(now, rt->expires)) {
2309                         RT6_TRACE("expiring %p\n", rt);
2310                         return -1;
2311                 }
2312                 gc_args->more++;
2313         }
2314
2315         /*      Also age clones in the exception table.
2316          *      Note, that clones are aged out
2317          *      only if they are not in use now.
2318          */
2319         rt6_age_exceptions(rt, gc_args, now);
2320
2321         return 0;
2322 }
2323
2324 static void fib6_gc_table(struct net *net,
2325                           struct fib6_table *tb6,
2326                           struct fib6_gc_args *gc_args)
2327 {
2328         struct fib6_info *rt;
2329         struct hlist_node *n;
2330         struct nl_info info = {
2331                 .nl_net = net,
2332                 .skip_notify = false,
2333         };
2334
2335         hlist_for_each_entry_safe(rt, n, &tb6->tb6_gc_hlist, gc_link)
2336                 if (fib6_age(rt, gc_args) == -1)
2337                         fib6_del(rt, &info);
2338 }
2339
2340 static void fib6_gc_all(struct net *net, struct fib6_gc_args *gc_args)
2341 {
2342         struct fib6_table *table;
2343         struct hlist_head *head;
2344         unsigned int h;
2345
2346         rcu_read_lock();
2347         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
2348                 head = &net->ipv6.fib_table_hash[h];
2349                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
2350                         spin_lock_bh(&table->tb6_lock);
2351                         fib6_gc_table(net, table, gc_args);
2352                         spin_unlock_bh(&table->tb6_lock);
2353                 }
2354         }
2355         rcu_read_unlock();
2356 }
2357
2358 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
2359 {
2360         struct fib6_gc_args gc_args;
2361         unsigned long now;
2362
2363         if (force) {
2364                 spin_lock_bh(&net->ipv6.fib6_gc_lock);
2365         } else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
2366                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
2367                 return;
2368         }
2369         gc_args.timeout = expires ? (int)expires :
2370                           net->ipv6.sysctl.ip6_rt_gc_interval;
2371         gc_args.more = 0;
2372
2373         fib6_gc_all(net, &gc_args);
2374         now = jiffies;
2375         net->ipv6.ip6_rt_last_gc = now;
2376
2377         if (gc_args.more)
2378                 mod_timer(&net->ipv6.ip6_fib_timer,
2379                           round_jiffies(now
2380                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
2381         else
2382                 del_timer(&net->ipv6.ip6_fib_timer);
2383         spin_unlock_bh(&net->ipv6.fib6_gc_lock);
2384 }
2385
2386 static void fib6_gc_timer_cb(struct timer_list *t)
2387 {
2388         struct net *arg = from_timer(arg, t, ipv6.ip6_fib_timer);
2389
2390         fib6_run_gc(0, arg, true);
2391 }
2392
2393 static int __net_init fib6_net_init(struct net *net)
2394 {
2395         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
2396         int err;
2397
2398         err = fib6_notifier_init(net);
2399         if (err)
2400                 return err;
2401
2402         /* Default to 3-tuple */
2403         net->ipv6.sysctl.multipath_hash_fields =
2404                 FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
2405
2406         spin_lock_init(&net->ipv6.fib6_gc_lock);
2407         rwlock_init(&net->ipv6.fib6_walker_lock);
2408         INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
2409         timer_setup(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, 0);
2410
2411         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
2412         if (!net->ipv6.rt6_stats)
2413                 goto out_notifier;
2414
2415         /* Avoid false sharing : Use at least a full cache line */
2416         size = max_t(size_t, size, L1_CACHE_BYTES);
2417
2418         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
2419         if (!net->ipv6.fib_table_hash)
2420                 goto out_rt6_stats;
2421
2422         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
2423                                           GFP_KERNEL);
2424         if (!net->ipv6.fib6_main_tbl)
2425                 goto out_fib_table_hash;
2426
2427         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
2428         rcu_assign_pointer(net->ipv6.fib6_main_tbl->tb6_root.leaf,
2429                            net->ipv6.fib6_null_entry);
2430         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
2431                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2432         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
2433
2434 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2435         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
2436                                            GFP_KERNEL);
2437         if (!net->ipv6.fib6_local_tbl)
2438                 goto out_fib6_main_tbl;
2439         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
2440         rcu_assign_pointer(net->ipv6.fib6_local_tbl->tb6_root.leaf,
2441                            net->ipv6.fib6_null_entry);
2442         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
2443                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2444         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
2445 #endif
2446         fib6_tables_init(net);
2447
2448         return 0;
2449
2450 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2451 out_fib6_main_tbl:
2452         kfree(net->ipv6.fib6_main_tbl);
2453 #endif
2454 out_fib_table_hash:
2455         kfree(net->ipv6.fib_table_hash);
2456 out_rt6_stats:
2457         kfree(net->ipv6.rt6_stats);
2458 out_notifier:
2459         fib6_notifier_exit(net);
2460         return -ENOMEM;
2461 }
2462
2463 static void fib6_net_exit(struct net *net)
2464 {
2465         unsigned int i;
2466
2467         del_timer_sync(&net->ipv6.ip6_fib_timer);
2468
2469         for (i = 0; i < FIB6_TABLE_HASHSZ; i++) {
2470                 struct hlist_head *head = &net->ipv6.fib_table_hash[i];
2471                 struct hlist_node *tmp;
2472                 struct fib6_table *tb;
2473
2474                 hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
2475                         hlist_del(&tb->tb6_hlist);
2476                         fib6_free_table(tb);
2477                 }
2478         }
2479
2480         kfree(net->ipv6.fib_table_hash);
2481         kfree(net->ipv6.rt6_stats);
2482         fib6_notifier_exit(net);
2483 }
2484
2485 static struct pernet_operations fib6_net_ops = {
2486         .init = fib6_net_init,
2487         .exit = fib6_net_exit,
2488 };
2489
2490 int __init fib6_init(void)
2491 {
2492         int ret = -ENOMEM;
2493
2494         fib6_node_kmem = kmem_cache_create("fib6_nodes",
2495                                            sizeof(struct fib6_node), 0,
2496                                            SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
2497                                            NULL);
2498         if (!fib6_node_kmem)
2499                 goto out;
2500
2501         ret = register_pernet_subsys(&fib6_net_ops);
2502         if (ret)
2503                 goto out_kmem_cache_create;
2504
2505         ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETROUTE, NULL,
2506                                    inet6_dump_fib, 0);
2507         if (ret)
2508                 goto out_unregister_subsys;
2509
2510         __fib6_flush_trees = fib6_flush_trees;
2511 out:
2512         return ret;
2513
2514 out_unregister_subsys:
2515         unregister_pernet_subsys(&fib6_net_ops);
2516 out_kmem_cache_create:
2517         kmem_cache_destroy(fib6_node_kmem);
2518         goto out;
2519 }
2520
2521 void fib6_gc_cleanup(void)
2522 {
2523         unregister_pernet_subsys(&fib6_net_ops);
2524         kmem_cache_destroy(fib6_node_kmem);
2525 }
2526
2527 #ifdef CONFIG_PROC_FS
2528 static int ipv6_route_native_seq_show(struct seq_file *seq, void *v)
2529 {
2530         struct fib6_info *rt = v;
2531         struct ipv6_route_iter *iter = seq->private;
2532         struct fib6_nh *fib6_nh = rt->fib6_nh;
2533         unsigned int flags = rt->fib6_flags;
2534         const struct net_device *dev;
2535
2536         if (rt->nh)
2537                 fib6_nh = nexthop_fib6_nh(rt->nh);
2538
2539         seq_printf(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen);
2540
2541 #ifdef CONFIG_IPV6_SUBTREES
2542         seq_printf(seq, "%pi6 %02x ", &rt->fib6_src.addr, rt->fib6_src.plen);
2543 #else
2544         seq_puts(seq, "00000000000000000000000000000000 00 ");
2545 #endif
2546         if (fib6_nh->fib_nh_gw_family) {
2547                 flags |= RTF_GATEWAY;
2548                 seq_printf(seq, "%pi6", &fib6_nh->fib_nh_gw6);
2549         } else {
2550                 seq_puts(seq, "00000000000000000000000000000000");
2551         }
2552
2553         dev = fib6_nh->fib_nh_dev;
2554         seq_printf(seq, " %08x %08x %08x %08x %8s\n",
2555                    rt->fib6_metric, refcount_read(&rt->fib6_ref), 0,
2556                    flags, dev ? dev->name : "");
2557         iter->w.leaf = NULL;
2558         return 0;
2559 }
2560
2561 static int ipv6_route_yield(struct fib6_walker *w)
2562 {
2563         struct ipv6_route_iter *iter = w->args;
2564
2565         if (!iter->skip)
2566                 return 1;
2567
2568         do {
2569                 iter->w.leaf = rcu_dereference_protected(
2570                                 iter->w.leaf->fib6_next,
2571                                 lockdep_is_held(&iter->tbl->tb6_lock));
2572                 iter->skip--;
2573                 if (!iter->skip && iter->w.leaf)
2574                         return 1;
2575         } while (iter->w.leaf);
2576
2577         return 0;
2578 }
2579
2580 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
2581                                       struct net *net)
2582 {
2583         memset(&iter->w, 0, sizeof(iter->w));
2584         iter->w.func = ipv6_route_yield;
2585         iter->w.root = &iter->tbl->tb6_root;
2586         iter->w.state = FWS_INIT;
2587         iter->w.node = iter->w.root;
2588         iter->w.args = iter;
2589         iter->sernum = READ_ONCE(iter->w.root->fn_sernum);
2590         INIT_LIST_HEAD(&iter->w.lh);
2591         fib6_walker_link(net, &iter->w);
2592 }
2593
2594 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
2595                                                     struct net *net)
2596 {
2597         unsigned int h;
2598         struct hlist_node *node;
2599
2600         if (tbl) {
2601                 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
2602                 node = rcu_dereference(hlist_next_rcu(&tbl->tb6_hlist));
2603         } else {
2604                 h = 0;
2605                 node = NULL;
2606         }
2607
2608         while (!node && h < FIB6_TABLE_HASHSZ) {
2609                 node = rcu_dereference(
2610                         hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
2611         }
2612         return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
2613 }
2614
2615 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
2616 {
2617         int sernum = READ_ONCE(iter->w.root->fn_sernum);
2618
2619         if (iter->sernum != sernum) {
2620                 iter->sernum = sernum;
2621                 iter->w.state = FWS_INIT;
2622                 iter->w.node = iter->w.root;
2623                 WARN_ON(iter->w.skip);
2624                 iter->w.skip = iter->w.count;
2625         }
2626 }
2627
2628 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2629 {
2630         int r;
2631         struct fib6_info *n;
2632         struct net *net = seq_file_net(seq);
2633         struct ipv6_route_iter *iter = seq->private;
2634
2635         ++(*pos);
2636         if (!v)
2637                 goto iter_table;
2638
2639         n = rcu_dereference(((struct fib6_info *)v)->fib6_next);
2640         if (n)
2641                 return n;
2642
2643 iter_table:
2644         ipv6_route_check_sernum(iter);
2645         spin_lock_bh(&iter->tbl->tb6_lock);
2646         r = fib6_walk_continue(&iter->w);
2647         spin_unlock_bh(&iter->tbl->tb6_lock);
2648         if (r > 0) {
2649                 return iter->w.leaf;
2650         } else if (r < 0) {
2651                 fib6_walker_unlink(net, &iter->w);
2652                 return NULL;
2653         }
2654         fib6_walker_unlink(net, &iter->w);
2655
2656         iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
2657         if (!iter->tbl)
2658                 return NULL;
2659
2660         ipv6_route_seq_setup_walk(iter, net);
2661         goto iter_table;
2662 }
2663
2664 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
2665         __acquires(RCU)
2666 {
2667         struct net *net = seq_file_net(seq);
2668         struct ipv6_route_iter *iter = seq->private;
2669
2670         rcu_read_lock();
2671         iter->tbl = ipv6_route_seq_next_table(NULL, net);
2672         iter->skip = *pos;
2673
2674         if (iter->tbl) {
2675                 loff_t p = 0;
2676
2677                 ipv6_route_seq_setup_walk(iter, net);
2678                 return ipv6_route_seq_next(seq, NULL, &p);
2679         } else {
2680                 return NULL;
2681         }
2682 }
2683
2684 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
2685 {
2686         struct fib6_walker *w = &iter->w;
2687         return w->node && !(w->state == FWS_U && w->node == w->root);
2688 }
2689
2690 static void ipv6_route_native_seq_stop(struct seq_file *seq, void *v)
2691         __releases(RCU)
2692 {
2693         struct net *net = seq_file_net(seq);
2694         struct ipv6_route_iter *iter = seq->private;
2695
2696         if (ipv6_route_iter_active(iter))
2697                 fib6_walker_unlink(net, &iter->w);
2698
2699         rcu_read_unlock();
2700 }
2701
2702 #if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
2703 static int ipv6_route_prog_seq_show(struct bpf_prog *prog,
2704                                     struct bpf_iter_meta *meta,
2705                                     void *v)
2706 {
2707         struct bpf_iter__ipv6_route ctx;
2708
2709         ctx.meta = meta;
2710         ctx.rt = v;
2711         return bpf_iter_run_prog(prog, &ctx);
2712 }
2713
2714 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2715 {
2716         struct ipv6_route_iter *iter = seq->private;
2717         struct bpf_iter_meta meta;
2718         struct bpf_prog *prog;
2719         int ret;
2720
2721         meta.seq = seq;
2722         prog = bpf_iter_get_info(&meta, false);
2723         if (!prog)
2724                 return ipv6_route_native_seq_show(seq, v);
2725
2726         ret = ipv6_route_prog_seq_show(prog, &meta, v);
2727         iter->w.leaf = NULL;
2728
2729         return ret;
2730 }
2731
2732 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2733 {
2734         struct bpf_iter_meta meta;
2735         struct bpf_prog *prog;
2736
2737         if (!v) {
2738                 meta.seq = seq;
2739                 prog = bpf_iter_get_info(&meta, true);
2740                 if (prog)
2741                         (void)ipv6_route_prog_seq_show(prog, &meta, v);
2742         }
2743
2744         ipv6_route_native_seq_stop(seq, v);
2745 }
2746 #else
2747 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2748 {
2749         return ipv6_route_native_seq_show(seq, v);
2750 }
2751
2752 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2753 {
2754         ipv6_route_native_seq_stop(seq, v);
2755 }
2756 #endif
2757
2758 const struct seq_operations ipv6_route_seq_ops = {
2759         .start  = ipv6_route_seq_start,
2760         .next   = ipv6_route_seq_next,
2761         .stop   = ipv6_route_seq_stop,
2762         .show   = ipv6_route_seq_show
2763 };
2764 #endif /* CONFIG_PROC_FS */