net/ipv6/ip6_fib.c

   1 /*
   2  *      Linux INET6 implementation
   3  *      Forwarding Information Database
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  *
  13  *      Changes:
  14  *      Yuji SEKIYA @USAGI:     Support default route on router node;
  15  *                              remove ip6_null_entry from the top of
  16  *                              routing table.
  17  *      Ville Nuorvala:         Fixed routing subtrees.
  18  */
  19
  20 #define pr_fmt(fmt) "IPv6: " fmt
  21
  22 #include <linux/errno.h>
  23 #include <linux/types.h>
  24 #include <linux/net.h>
  25 #include <linux/route.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/in6.h>
  28 #include <linux/init.h>
  29 #include <linux/list.h>
  30 #include <linux/slab.h>
  31
  32 #include <net/ip.h>
  33 #include <net/ipv6.h>
  34 #include <net/ndisc.h>
  35 #include <net/addrconf.h>
  36 #include <net/lwtunnel.h>
  37 #include <net/fib_notifier.h>
  38
  39 #include <net/ip6_fib.h>
  40 #include <net/ip6_route.h>
  41
  42 static struct kmem_cache *fib6_node_kmem __read_mostly;
  43
  44 struct fib6_cleaner {
  45         struct fib6_walker w;
  46         struct net *net;
  47         int (*func)(struct fib6_info *, void *arg);
  48         int sernum;
  49         void *arg;
  50         bool skip_notify;
  51 };
  52
  53 #ifdef CONFIG_IPV6_SUBTREES
  54 #define FWS_INIT FWS_S
  55 #else
  56 #define FWS_INIT FWS_L
  57 #endif
  58
  59 static struct fib6_info *fib6_find_prefix(struct net *net,
  60                                          struct fib6_table *table,
  61                                          struct fib6_node *fn);
  62 static struct fib6_node *fib6_repair_tree(struct net *net,
  63                                           struct fib6_table *table,
  64                                           struct fib6_node *fn);
  65 static int fib6_walk(struct net *net, struct fib6_walker *w);
  66 static int fib6_walk_continue(struct fib6_walker *w);
  67
  68 /*
  69  *      A routing update causes an increase of the serial number on the
  70  *      affected subtree. This allows for cached routes to be asynchronously
  71  *      tested when modifications are made to the destination cache as a
  72  *      result of redirects, path MTU changes, etc.
  73  */
  74
  75 static void fib6_gc_timer_cb(struct timer_list *t);
  76
  77 #define FOR_WALKERS(net, w) \
  78         list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)
  79
  80 static void fib6_walker_link(struct net *net, struct fib6_walker *w)
  81 {
  82         write_lock_bh(&net->ipv6.fib6_walker_lock);
  83         list_add(&w->lh, &net->ipv6.fib6_walkers);
  84         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  85 }
  86
  87 static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
  88 {
  89         write_lock_bh(&net->ipv6.fib6_walker_lock);
  90         list_del(&w->lh);
  91         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  92 }
  93
  94 static int fib6_new_sernum(struct net *net)
  95 {
  96         int new, old;
  97
  98         do {
  99                 old = atomic_read(&net->ipv6.fib6_sernum);
 100                 new = old < INT_MAX ? old + 1 : 1;
 101         } while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
 102                                 old, new) != old);
 103         return new;
 104 }
 105
 106 enum {
 107         FIB6_NO_SERNUM_CHANGE = 0,
 108 };
 109
 110 void fib6_update_sernum(struct net *net, struct fib6_info *f6i)
 111 {
 112         struct fib6_node *fn;
 113
 114         fn = rcu_dereference_protected(f6i->fib6_node,
 115                         lockdep_is_held(&f6i->fib6_table->tb6_lock));
 116         if (fn)
 117                 fn->fn_sernum = fib6_new_sernum(net);
 118 }
 119
 120 /*
 121  *      Auxiliary address test functions for the radix tree.
 122  *
 123  *      These assume a 32bit processor (although it will work on
 124  *      64bit processors)
 125  */
 126
 127 /*
 128  *      test bit
 129  */
 130 #if defined(__LITTLE_ENDIAN)
 131 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
 132 #else
 133 # define BITOP_BE32_SWIZZLE     0
 134 #endif
 135
 136 static __be32 addr_bit_set(const void *token, int fn_bit)
 137 {
 138         const __be32 *addr = token;
 139         /*
 140          * Here,
 141          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
 142          * is optimized version of
 143          *      htonl(1 << ((~fn_bit)&0x1F))
 144          * See include/asm-generic/bitops/le.h.
 145          */
 146         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
 147                addr[fn_bit >> 5];
 148 }
 149
 150 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags)
 151 {
 152         struct fib6_info *f6i;
 153
 154         f6i = kzalloc(sizeof(*f6i), gfp_flags);
 155         if (!f6i)
 156                 return NULL;
 157
 158         f6i->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags);
 159         if (!f6i->rt6i_pcpu) {
 160                 kfree(f6i);
 161                 return NULL;
 162         }
 163
 164         INIT_LIST_HEAD(&f6i->fib6_siblings);
 165         refcount_set(&f6i->fib6_ref, 1);
 166
 167         return f6i;
 168 }
 169
 170 void fib6_info_destroy_rcu(struct rcu_head *head)
 171 {
 172         struct fib6_info *f6i = container_of(head, struct fib6_info, rcu);
 173         struct rt6_exception_bucket *bucket;
 174
 175         WARN_ON(f6i->fib6_node);
 176
 177         bucket = rcu_dereference_protected(f6i->rt6i_exception_bucket, 1);
 178         kfree(bucket);
 179
 180         if (f6i->rt6i_pcpu) {
 181                 int cpu;
 182
 183                 for_each_possible_cpu(cpu) {
 184                         struct rt6_info **ppcpu_rt;
 185                         struct rt6_info *pcpu_rt;
 186
 187                         ppcpu_rt = per_cpu_ptr(f6i->rt6i_pcpu, cpu);
 188                         pcpu_rt = *ppcpu_rt;
 189                         if (pcpu_rt) {
 190                                 dst_dev_put(&pcpu_rt->dst);
 191                                 dst_release(&pcpu_rt->dst);
 192                                 *ppcpu_rt = NULL;
 193                         }
 194                 }
 195
 196                 free_percpu(f6i->rt6i_pcpu);
 197         }
 198
 199         fib6_nh_release(&f6i->fib6_nh);
 200
 201         ip_fib_metrics_put(f6i->fib6_metrics);
 202
 203         kfree(f6i);
 204 }
 205 EXPORT_SYMBOL_GPL(fib6_info_destroy_rcu);
 206
 207 static struct fib6_node *node_alloc(struct net *net)
 208 {
 209         struct fib6_node *fn;
 210
 211         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 212         if (fn)
 213                 net->ipv6.rt6_stats->fib_nodes++;
 214
 215         return fn;
 216 }
 217
 218 static void node_free_immediate(struct net *net, struct fib6_node *fn)
 219 {
 220         kmem_cache_free(fib6_node_kmem, fn);
 221         net->ipv6.rt6_stats->fib_nodes--;
 222 }
 223
 224 static void node_free_rcu(struct rcu_head *head)
 225 {
 226         struct fib6_node *fn = container_of(head, struct fib6_node, rcu);
 227
 228         kmem_cache_free(fib6_node_kmem, fn);
 229 }
 230
 231 static void node_free(struct net *net, struct fib6_node *fn)
 232 {
 233         call_rcu(&fn->rcu, node_free_rcu);
 234         net->ipv6.rt6_stats->fib_nodes--;
 235 }
 236
 237 static void fib6_free_table(struct fib6_table *table)
 238 {
 239         inetpeer_invalidate_tree(&table->tb6_peers);
 240         kfree(table);
 241 }
 242
 243 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 244 {
 245         unsigned int h;
 246
 247         /*
 248          * Initialize table lock at a single place to give lockdep a key,
 249          * tables aren't visible prior to being linked to the list.
 250          */
 251         spin_lock_init(&tb->tb6_lock);
 252         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 253
 254         /*
 255          * No protection necessary, this is the only list mutatation
 256          * operation, tables never disappear once they exist.
 257          */
 258         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 259 }
 260
 261 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 262
 263 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 264 {
 265         struct fib6_table *table;
 266
 267         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 268         if (table) {
 269                 table->tb6_id = id;
 270                 rcu_assign_pointer(table->tb6_root.leaf,
 271                                    net->ipv6.fib6_null_entry);
 272                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 273                 inet_peer_base_init(&table->tb6_peers);
 274         }
 275
 276         return table;
 277 }
 278
 279 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 280 {
 281         struct fib6_table *tb;
 282
 283         if (id == 0)
 284                 id = RT6_TABLE_MAIN;
 285         tb = fib6_get_table(net, id);
 286         if (tb)
 287                 return tb;
 288
 289         tb = fib6_alloc_table(net, id);
 290         if (tb)
 291                 fib6_link_table(net, tb);
 292
 293         return tb;
 294 }
 295 EXPORT_SYMBOL_GPL(fib6_new_table);
 296
 297 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 298 {
 299         struct fib6_table *tb;
 300         struct hlist_head *head;
 301         unsigned int h;
 302
 303         if (id == 0)
 304                 id = RT6_TABLE_MAIN;
 305         h = id & (FIB6_TABLE_HASHSZ - 1);
 306         rcu_read_lock();
 307         head = &net->ipv6.fib_table_hash[h];
 308         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 309                 if (tb->tb6_id == id) {
 310                         rcu_read_unlock();
 311                         return tb;
 312                 }
 313         }
 314         rcu_read_unlock();
 315
 316         return NULL;
 317 }
 318 EXPORT_SYMBOL_GPL(fib6_get_table);
 319
 320 static void __net_init fib6_tables_init(struct net *net)
 321 {
 322         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 323         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 324 }
 325 #else
 326
 327 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 328 {
 329         return fib6_get_table(net, id);
 330 }
 331
 332 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 333 {
 334           return net->ipv6.fib6_main_tbl;
 335 }
 336
 337 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 338                                    const struct sk_buff *skb,
 339                                    int flags, pol_lookup_t lookup)
 340 {
 341         struct rt6_info *rt;
 342
 343         rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
 344         if (rt->dst.error == -EAGAIN) {
 345                 ip6_rt_put(rt);
 346                 rt = net->ipv6.ip6_null_entry;
 347                 dst_hold(&rt->dst);
 348         }
 349
 350         return &rt->dst;
 351 }
 352
 353 /* called with rcu lock held; no reference taken on fib6_info */
 354 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 355                 struct fib6_result *res, int flags)
 356 {
 357         return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6,
 358                                  res, flags);
 359 }
 360
 361 static void __net_init fib6_tables_init(struct net *net)
 362 {
 363         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 364 }
 365
 366 #endif
 367
 368 unsigned int fib6_tables_seq_read(struct net *net)
 369 {
 370         unsigned int h, fib_seq = 0;
 371
 372         rcu_read_lock();
 373         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
 374                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
 375                 struct fib6_table *tb;
 376
 377                 hlist_for_each_entry_rcu(tb, head, tb6_hlist)
 378                         fib_seq += tb->fib_seq;
 379         }
 380         rcu_read_unlock();
 381
 382         return fib_seq;
 383 }
 384
 385 static int call_fib6_entry_notifier(struct notifier_block *nb, struct net *net,
 386                                     enum fib_event_type event_type,
 387                                     struct fib6_info *rt)
 388 {
 389         struct fib6_entry_notifier_info info = {
 390                 .rt = rt,
 391         };
 392
 393         return call_fib6_notifier(nb, net, event_type, &info.info);
 394 }
 395
 396 int call_fib6_entry_notifiers(struct net *net,
 397                               enum fib_event_type event_type,
 398                               struct fib6_info *rt,
 399                               struct netlink_ext_ack *extack)
 400 {
 401         struct fib6_entry_notifier_info info = {
 402                 .info.extack = extack,
 403                 .rt = rt,
 404         };
 405
 406         rt->fib6_table->fib_seq++;
 407         return call_fib6_notifiers(net, event_type, &info.info);
 408 }
 409
 410 struct fib6_dump_arg {
 411         struct net *net;
 412         struct notifier_block *nb;
 413 };
 414
 415 static void fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
 416 {
 417         if (rt == arg->net->ipv6.fib6_null_entry)
 418                 return;
 419         call_fib6_entry_notifier(arg->nb, arg->net, FIB_EVENT_ENTRY_ADD, rt);
 420 }
 421
 422 static int fib6_node_dump(struct fib6_walker *w)
 423 {
 424         struct fib6_info *rt;
 425
 426         for_each_fib6_walker_rt(w)
 427                 fib6_rt_dump(rt, w->args);
 428         w->leaf = NULL;
 429         return 0;
 430 }
 431
 432 static void fib6_table_dump(struct net *net, struct fib6_table *tb,
 433                             struct fib6_walker *w)
 434 {
 435         w->root = &tb->tb6_root;
 436         spin_lock_bh(&tb->tb6_lock);
 437         fib6_walk(net, w);
 438         spin_unlock_bh(&tb->tb6_lock);
 439 }
 440
 441 /* Called with rcu_read_lock() */
 442 int fib6_tables_dump(struct net *net, struct notifier_block *nb)
 443 {
 444         struct fib6_dump_arg arg;
 445         struct fib6_walker *w;
 446         unsigned int h;
 447
 448         w = kzalloc(sizeof(*w), GFP_ATOMIC);
 449         if (!w)
 450                 return -ENOMEM;
 451
 452         w->func = fib6_node_dump;
 453         arg.net = net;
 454         arg.nb = nb;
 455         w->args = &arg;
 456
 457         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
 458                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
 459                 struct fib6_table *tb;
 460
 461                 hlist_for_each_entry_rcu(tb, head, tb6_hlist)
 462                         fib6_table_dump(net, tb, w);
 463         }
 464
 465         kfree(w);
 466
 467         return 0;
 468 }
 469
 470 static int fib6_dump_node(struct fib6_walker *w)
 471 {
 472         int res;
 473         struct fib6_info *rt;
 474
 475         for_each_fib6_walker_rt(w) {
 476                 res = rt6_dump_route(rt, w->args);
 477                 if (res < 0) {
 478                         /* Frame is full, suspend walking */
 479                         w->leaf = rt;
 480                         return 1;
 481                 }
 482
 483                 /* Multipath routes are dumped in one route with the
 484                  * RTA_MULTIPATH attribute. Jump 'rt' to point to the
 485                  * last sibling of this route (no need to dump the
 486                  * sibling routes again)
 487                  */
 488                 if (rt->fib6_nsiblings)
 489                         rt = list_last_entry(&rt->fib6_siblings,
 490                                              struct fib6_info,
 491                                              fib6_siblings);
 492         }
 493         w->leaf = NULL;
 494         return 0;
 495 }
 496
 497 static void fib6_dump_end(struct netlink_callback *cb)
 498 {
 499         struct net *net = sock_net(cb->skb->sk);
 500         struct fib6_walker *w = (void *)cb->args[2];
 501
 502         if (w) {
 503                 if (cb->args[4]) {
 504                         cb->args[4] = 0;
 505                         fib6_walker_unlink(net, w);
 506                 }
 507                 cb->args[2] = 0;
 508                 kfree(w);
 509         }
 510         cb->done = (void *)cb->args[3];
 511         cb->args[1] = 3;
 512 }
 513
 514 static int fib6_dump_done(struct netlink_callback *cb)
 515 {
 516         fib6_dump_end(cb);
 517         return cb->done ? cb->done(cb) : 0;
 518 }
 519
 520 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 521                            struct netlink_callback *cb)
 522 {
 523         struct net *net = sock_net(skb->sk);
 524         struct fib6_walker *w;
 525         int res;
 526
 527         w = (void *)cb->args[2];
 528         w->root = &table->tb6_root;
 529
 530         if (cb->args[4] == 0) {
 531                 w->count = 0;
 532                 w->skip = 0;
 533
 534                 spin_lock_bh(&table->tb6_lock);
 535                 res = fib6_walk(net, w);
 536                 spin_unlock_bh(&table->tb6_lock);
 537                 if (res > 0) {
 538                         cb->args[4] = 1;
 539                         cb->args[5] = w->root->fn_sernum;
 540                 }
 541         } else {
 542                 if (cb->args[5] != w->root->fn_sernum) {
 543                         /* Begin at the root if the tree changed */
 544                         cb->args[5] = w->root->fn_sernum;
 545                         w->state = FWS_INIT;
 546                         w->node = w->root;
 547                         w->skip = w->count;
 548                 } else
 549                         w->skip = 0;
 550
 551                 spin_lock_bh(&table->tb6_lock);
 552                 res = fib6_walk_continue(w);
 553                 spin_unlock_bh(&table->tb6_lock);
 554                 if (res <= 0) {
 555                         fib6_walker_unlink(net, w);
 556                         cb->args[4] = 0;
 557                 }
 558         }
 559
 560         return res;
 561 }
 562
 563 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 564 {
 565         const struct nlmsghdr *nlh = cb->nlh;
 566         struct net *net = sock_net(skb->sk);
 567         struct rt6_rtnl_dump_arg arg = {};
 568         unsigned int h, s_h;
 569         unsigned int e = 0, s_e;
 570         struct fib6_walker *w;
 571         struct fib6_table *tb;
 572         struct hlist_head *head;
 573         int res = 0;
 574
 575         if (cb->strict_check) {
 576                 int err;
 577
 578                 err = ip_valid_fib_dump_req(net, nlh, &arg.filter, cb);
 579                 if (err < 0)
 580                         return err;
 581         } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
 582                 struct rtmsg *rtm = nlmsg_data(nlh);
 583
 584                 arg.filter.flags = rtm->rtm_flags & (RTM_F_PREFIX|RTM_F_CLONED);
 585         }
 586
 587         /* fib entries are never clones */
 588         if (arg.filter.flags & RTM_F_CLONED)
 589                 goto out;
 590
 591         w = (void *)cb->args[2];
 592         if (!w) {
 593                 /* New dump:
 594                  *
 595                  * 1. hook callback destructor.
 596                  */
 597                 cb->args[3] = (long)cb->done;
 598                 cb->done = fib6_dump_done;
 599
 600                 /*
 601                  * 2. allocate and initialize walker.
 602                  */
 603                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 604                 if (!w)
 605                         return -ENOMEM;
 606                 w->func = fib6_dump_node;
 607                 cb->args[2] = (long)w;
 608         }
 609
 610         arg.skb = skb;
 611         arg.cb = cb;
 612         arg.net = net;
 613         w->args = &arg;
 614
 615         if (arg.filter.table_id) {
 616                 tb = fib6_get_table(net, arg.filter.table_id);
 617                 if (!tb) {
 618                         if (arg.filter.dump_all_families)
 619                                 goto out;
 620
 621                         NL_SET_ERR_MSG_MOD(cb->extack, "FIB table does not exist");
 622                         return -ENOENT;
 623                 }
 624
 625                 if (!cb->args[0]) {
 626                         res = fib6_dump_table(tb, skb, cb);
 627                         if (!res)
 628                                 cb->args[0] = 1;
 629                 }
 630                 goto out;
 631         }
 632
 633         s_h = cb->args[0];
 634         s_e = cb->args[1];
 635
 636         rcu_read_lock();
 637         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 638                 e = 0;
 639                 head = &net->ipv6.fib_table_hash[h];
 640                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 641                         if (e < s_e)
 642                                 goto next;
 643                         res = fib6_dump_table(tb, skb, cb);
 644                         if (res != 0)
 645                                 goto out_unlock;
 646 next:
 647                         e++;
 648                 }
 649         }
 650 out_unlock:
 651         rcu_read_unlock();
 652         cb->args[1] = e;
 653         cb->args[0] = h;
 654 out:
 655         res = res < 0 ? res : skb->len;
 656         if (res <= 0)
 657                 fib6_dump_end(cb);
 658         return res;
 659 }
 660
 661 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val)
 662 {
 663         if (!f6i)
 664                 return;
 665
 666         if (f6i->fib6_metrics == &dst_default_metrics) {
 667                 struct dst_metrics *p = kzalloc(sizeof(*p), GFP_ATOMIC);
 668
 669                 if (!p)
 670                         return;
 671
 672                 refcount_set(&p->refcnt, 1);
 673                 f6i->fib6_metrics = p;
 674         }
 675
 676         f6i->fib6_metrics->metrics[metric - 1] = val;
 677 }
 678
 679 /*
 680  *      Routing Table
 681  *
 682  *      return the appropriate node for a routing tree "add" operation
 683  *      by either creating and inserting or by returning an existing
 684  *      node.
 685  */
 686
 687 static struct fib6_node *fib6_add_1(struct net *net,
 688                                     struct fib6_table *table,
 689                                     struct fib6_node *root,
 690                                     struct in6_addr *addr, int plen,
 691                                     int offset, int allow_create,
 692                                     int replace_required,
 693                                     struct netlink_ext_ack *extack)
 694 {
 695         struct fib6_node *fn, *in, *ln;
 696         struct fib6_node *pn = NULL;
 697         struct rt6key *key;
 698         int     bit;
 699         __be32  dir = 0;
 700
 701         RT6_TRACE("fib6_add_1\n");
 702
 703         /* insert node in tree */
 704
 705         fn = root;
 706
 707         do {
 708                 struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
 709                                             lockdep_is_held(&table->tb6_lock));
 710                 key = (struct rt6key *)((u8 *)leaf + offset);
 711
 712                 /*
 713                  *      Prefix match
 714                  */
 715                 if (plen < fn->fn_bit ||
 716                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 717                         if (!allow_create) {
 718                                 if (replace_required) {
 719                                         NL_SET_ERR_MSG(extack,
 720                                                        "Can not replace route - no match found");
 721                                         pr_warn("Can't replace route, no match found\n");
 722                                         return ERR_PTR(-ENOENT);
 723                                 }
 724                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 725                         }
 726                         goto insert_above;
 727                 }
 728
 729                 /*
 730                  *      Exact match ?
 731                  */
 732
 733                 if (plen == fn->fn_bit) {
 734                         /* clean up an intermediate node */
 735                         if (!(fn->fn_flags & RTN_RTINFO)) {
 736                                 RCU_INIT_POINTER(fn->leaf, NULL);
 737                                 fib6_info_release(leaf);
 738                         /* remove null_entry in the root node */
 739                         } else if (fn->fn_flags & RTN_TL_ROOT &&
 740                                    rcu_access_pointer(fn->leaf) ==
 741                                    net->ipv6.fib6_null_entry) {
 742                                 RCU_INIT_POINTER(fn->leaf, NULL);
 743                         }
 744
 745                         return fn;
 746                 }
 747
 748                 /*
 749                  *      We have more bits to go
 750                  */
 751
 752                 /* Try to walk down on tree. */
 753                 dir = addr_bit_set(addr, fn->fn_bit);
 754                 pn = fn;
 755                 fn = dir ?
 756                      rcu_dereference_protected(fn->right,
 757                                         lockdep_is_held(&table->tb6_lock)) :
 758                      rcu_dereference_protected(fn->left,
 759                                         lockdep_is_held(&table->tb6_lock));
 760         } while (fn);
 761
 762         if (!allow_create) {
 763                 /* We should not create new node because
 764                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 765                  * I assume it is safe to require NLM_F_CREATE when
 766                  * REPLACE flag is used! Later we may want to remove the
 767                  * check for replace_required, because according
 768                  * to netlink specification, NLM_F_CREATE
 769                  * MUST be specified if new route is created.
 770                  * That would keep IPv6 consistent with IPv4
 771                  */
 772                 if (replace_required) {
 773                         NL_SET_ERR_MSG(extack,
 774                                        "Can not replace route - no match found");
 775                         pr_warn("Can't replace route, no match found\n");
 776                         return ERR_PTR(-ENOENT);
 777                 }
 778                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 779         }
 780         /*
 781          *      We walked to the bottom of tree.
 782          *      Create new leaf node without children.
 783          */
 784
 785         ln = node_alloc(net);
 786
 787         if (!ln)
 788                 return ERR_PTR(-ENOMEM);
 789         ln->fn_bit = plen;
 790         RCU_INIT_POINTER(ln->parent, pn);
 791
 792         if (dir)
 793                 rcu_assign_pointer(pn->right, ln);
 794         else
 795                 rcu_assign_pointer(pn->left, ln);
 796
 797         return ln;
 798
 799
 800 insert_above:
 801         /*
 802          * split since we don't have a common prefix anymore or
 803          * we have a less significant route.
 804          * we've to insert an intermediate node on the list
 805          * this new node will point to the one we need to create
 806          * and the current
 807          */
 808
 809         pn = rcu_dereference_protected(fn->parent,
 810                                        lockdep_is_held(&table->tb6_lock));
 811
 812         /* find 1st bit in difference between the 2 addrs.
 813
 814            See comment in __ipv6_addr_diff: bit may be an invalid value,
 815            but if it is >= plen, the value is ignored in any case.
 816          */
 817
 818         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 819
 820         /*
 821          *              (intermediate)[in]
 822          *                /        \
 823          *      (new leaf node)[ln] (old node)[fn]
 824          */
 825         if (plen > bit) {
 826                 in = node_alloc(net);
 827                 ln = node_alloc(net);
 828
 829                 if (!in || !ln) {
 830                         if (in)
 831                                 node_free_immediate(net, in);
 832                         if (ln)
 833                                 node_free_immediate(net, ln);
 834                         return ERR_PTR(-ENOMEM);
 835                 }
 836
 837                 /*
 838                  * new intermediate node.
 839                  * RTN_RTINFO will
 840                  * be off since that an address that chooses one of
 841                  * the branches would not match less specific routes
 842                  * in the other branch
 843                  */
 844
 845                 in->fn_bit = bit;
 846
 847                 RCU_INIT_POINTER(in->parent, pn);
 848                 in->leaf = fn->leaf;
 849                 fib6_info_hold(rcu_dereference_protected(in->leaf,
 850                                 lockdep_is_held(&table->tb6_lock)));
 851
 852                 /* update parent pointer */
 853                 if (dir)
 854                         rcu_assign_pointer(pn->right, in);
 855                 else
 856                         rcu_assign_pointer(pn->left, in);
 857
 858                 ln->fn_bit = plen;
 859
 860                 RCU_INIT_POINTER(ln->parent, in);
 861                 rcu_assign_pointer(fn->parent, in);
 862
 863                 if (addr_bit_set(addr, bit)) {
 864                         rcu_assign_pointer(in->right, ln);
 865                         rcu_assign_pointer(in->left, fn);
 866                 } else {
 867                         rcu_assign_pointer(in->left, ln);
 868                         rcu_assign_pointer(in->right, fn);
 869                 }
 870         } else { /* plen <= bit */
 871
 872                 /*
 873                  *              (new leaf node)[ln]
 874                  *                /        \
 875                  *           (old node)[fn] NULL
 876                  */
 877
 878                 ln = node_alloc(net);
 879
 880                 if (!ln)
 881                         return ERR_PTR(-ENOMEM);
 882
 883                 ln->fn_bit = plen;
 884
 885                 RCU_INIT_POINTER(ln->parent, pn);
 886
 887                 if (addr_bit_set(&key->addr, plen))
 888                         RCU_INIT_POINTER(ln->right, fn);
 889                 else
 890                         RCU_INIT_POINTER(ln->left, fn);
 891
 892                 rcu_assign_pointer(fn->parent, ln);
 893
 894                 if (dir)
 895                         rcu_assign_pointer(pn->right, ln);
 896                 else
 897                         rcu_assign_pointer(pn->left, ln);
 898         }
 899         return ln;
 900 }
 901
 902 static void fib6_drop_pcpu_from(struct fib6_info *f6i,
 903                                 const struct fib6_table *table)
 904 {
 905         int cpu;
 906
 907         /* Make sure rt6_make_pcpu_route() wont add other percpu routes
 908          * while we are cleaning them here.
 909          */
 910         f6i->fib6_destroying = 1;
 911         mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
 912
 913         /* release the reference to this fib entry from
 914          * all of its cached pcpu routes
 915          */
 916         for_each_possible_cpu(cpu) {
 917                 struct rt6_info **ppcpu_rt;
 918                 struct rt6_info *pcpu_rt;
 919
 920                 ppcpu_rt = per_cpu_ptr(f6i->rt6i_pcpu, cpu);
 921                 pcpu_rt = *ppcpu_rt;
 922                 if (pcpu_rt) {
 923                         struct fib6_info *from;
 924
 925                         from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
 926                         fib6_info_release(from);
 927                 }
 928         }
 929 }
 930
 931 static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn,
 932                           struct net *net)
 933 {
 934         struct fib6_table *table = rt->fib6_table;
 935
 936         if (rt->rt6i_pcpu)
 937                 fib6_drop_pcpu_from(rt, table);
 938
 939         if (refcount_read(&rt->fib6_ref) != 1) {
 940                 /* This route is used as dummy address holder in some split
 941                  * nodes. It is not leaked, but it still holds other resources,
 942                  * which must be released in time. So, scan ascendant nodes
 943                  * and replace dummy references to this route with references
 944                  * to still alive ones.
 945                  */
 946                 while (fn) {
 947                         struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
 948                                             lockdep_is_held(&table->tb6_lock));
 949                         struct fib6_info *new_leaf;
 950                         if (!(fn->fn_flags & RTN_RTINFO) && leaf == rt) {
 951                                 new_leaf = fib6_find_prefix(net, table, fn);
 952                                 fib6_info_hold(new_leaf);
 953
 954                                 rcu_assign_pointer(fn->leaf, new_leaf);
 955                                 fib6_info_release(rt);
 956                         }
 957                         fn = rcu_dereference_protected(fn->parent,
 958                                     lockdep_is_held(&table->tb6_lock));
 959                 }
 960         }
 961 }
 962
 963 /*
 964  *      Insert routing information in a node.
 965  */
 966
 967 static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
 968                             struct nl_info *info,
 969                             struct netlink_ext_ack *extack)
 970 {
 971         struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
 972                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
 973         struct fib6_info *iter = NULL;
 974         struct fib6_info __rcu **ins;
 975         struct fib6_info __rcu **fallback_ins = NULL;
 976         int replace = (info->nlh &&
 977                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 978         int add = (!info->nlh ||
 979                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
 980         int found = 0;
 981         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
 982         u16 nlflags = NLM_F_EXCL;
 983         int err;
 984
 985         if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))
 986                 nlflags |= NLM_F_APPEND;
 987
 988         ins = &fn->leaf;
 989
 990         for (iter = leaf; iter;
 991              iter = rcu_dereference_protected(iter->fib6_next,
 992                                 lockdep_is_held(&rt->fib6_table->tb6_lock))) {
 993                 /*
 994                  *      Search for duplicates
 995                  */
 996
 997                 if (iter->fib6_metric == rt->fib6_metric) {
 998                         /*
 999                          *      Same priority level
1000                          */
1001                         if (info->nlh &&
1002                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
1003                                 return -EEXIST;
1004
1005                         nlflags &= ~NLM_F_EXCL;
1006                         if (replace) {
1007                                 if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
1008                                         found++;
1009                                         break;
1010                                 }
1011                                 if (rt_can_ecmp)
1012                                         fallback_ins = fallback_ins ?: ins;
1013                                 goto next_iter;
1014                         }
1015
1016                         if (rt6_duplicate_nexthop(iter, rt)) {
1017                                 if (rt->fib6_nsiblings)
1018                                         rt->fib6_nsiblings = 0;
1019                                 if (!(iter->fib6_flags & RTF_EXPIRES))
1020                                         return -EEXIST;
1021                                 if (!(rt->fib6_flags & RTF_EXPIRES))
1022                                         fib6_clean_expires(iter);
1023                                 else
1024                                         fib6_set_expires(iter, rt->expires);
1025
1026                                 if (rt->fib6_pmtu)
1027                                         fib6_metric_set(iter, RTAX_MTU,
1028                                                         rt->fib6_pmtu);
1029                                 return -EEXIST;
1030                         }
1031                         /* If we have the same destination and the same metric,
1032                          * but not the same gateway, then the route we try to
1033                          * add is sibling to this route, increment our counter
1034                          * of siblings, and later we will add our route to the
1035                          * list.
1036                          * Only static routes (which don't have flag
1037                          * RTF_EXPIRES) are used for ECMPv6.
1038                          *
1039                          * To avoid long list, we only had siblings if the
1040                          * route have a gateway.
1041                          */
1042                         if (rt_can_ecmp &&
1043                             rt6_qualify_for_ecmp(iter))
1044                                 rt->fib6_nsiblings++;
1045                 }
1046
1047                 if (iter->fib6_metric > rt->fib6_metric)
1048                         break;
1049
1050 next_iter:
1051                 ins = &iter->fib6_next;
1052         }
1053
1054         if (fallback_ins && !found) {
1055                 /* No ECMP-able route found, replace first non-ECMP one */
1056                 ins = fallback_ins;
1057                 iter = rcu_dereference_protected(*ins,
1058                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1059                 found++;
1060         }
1061
1062         /* Reset round-robin state, if necessary */
1063         if (ins == &fn->leaf)
1064                 fn->rr_ptr = NULL;
1065
1066         /* Link this route to others same route. */
1067         if (rt->fib6_nsiblings) {
1068                 unsigned int fib6_nsiblings;
1069                 struct fib6_info *sibling, *temp_sibling;
1070
1071                 /* Find the first route that have the same metric */
1072                 sibling = leaf;
1073                 while (sibling) {
1074                         if (sibling->fib6_metric == rt->fib6_metric &&
1075                             rt6_qualify_for_ecmp(sibling)) {
1076                                 list_add_tail(&rt->fib6_siblings,
1077                                               &sibling->fib6_siblings);
1078                                 break;
1079                         }
1080                         sibling = rcu_dereference_protected(sibling->fib6_next,
1081                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1082                 }
1083                 /* For each sibling in the list, increment the counter of
1084                  * siblings. BUG() if counters does not match, list of siblings
1085                  * is broken!
1086                  */
1087                 fib6_nsiblings = 0;
1088                 list_for_each_entry_safe(sibling, temp_sibling,
1089                                          &rt->fib6_siblings, fib6_siblings) {
1090                         sibling->fib6_nsiblings++;
1091                         BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings);
1092                         fib6_nsiblings++;
1093                 }
1094                 BUG_ON(fib6_nsiblings != rt->fib6_nsiblings);
1095                 rt6_multipath_rebalance(temp_sibling);
1096         }
1097
1098         /*
1099          *      insert node
1100          */
1101         if (!replace) {
1102                 if (!add)
1103                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
1104
1105 add:
1106                 nlflags |= NLM_F_CREATE;
1107
1108                 err = call_fib6_entry_notifiers(info->nl_net,
1109                                                 FIB_EVENT_ENTRY_ADD,
1110                                                 rt, extack);
1111                 if (err)
1112                         return err;
1113
1114                 rcu_assign_pointer(rt->fib6_next, iter);
1115                 fib6_info_hold(rt);
1116                 rcu_assign_pointer(rt->fib6_node, fn);
1117                 rcu_assign_pointer(*ins, rt);
1118                 if (!info->skip_notify)
1119                         inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
1120                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
1121
1122                 if (!(fn->fn_flags & RTN_RTINFO)) {
1123                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1124                         fn->fn_flags |= RTN_RTINFO;
1125                 }
1126
1127         } else {
1128                 int nsiblings;
1129
1130                 if (!found) {
1131                         if (add)
1132                                 goto add;
1133                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
1134                         return -ENOENT;
1135                 }
1136
1137                 err = call_fib6_entry_notifiers(info->nl_net,
1138                                                 FIB_EVENT_ENTRY_REPLACE,
1139                                                 rt, extack);
1140                 if (err)
1141                         return err;
1142
1143                 fib6_info_hold(rt);
1144                 rcu_assign_pointer(rt->fib6_node, fn);
1145                 rt->fib6_next = iter->fib6_next;
1146                 rcu_assign_pointer(*ins, rt);
1147                 if (!info->skip_notify)
1148                         inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
1149                 if (!(fn->fn_flags & RTN_RTINFO)) {
1150                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1151                         fn->fn_flags |= RTN_RTINFO;
1152                 }
1153                 nsiblings = iter->fib6_nsiblings;
1154                 iter->fib6_node = NULL;
1155                 fib6_purge_rt(iter, fn, info->nl_net);
1156                 if (rcu_access_pointer(fn->rr_ptr) == iter)
1157                         fn->rr_ptr = NULL;
1158                 fib6_info_release(iter);
1159
1160                 if (nsiblings) {
1161                         /* Replacing an ECMP route, remove all siblings */
1162                         ins = &rt->fib6_next;
1163                         iter = rcu_dereference_protected(*ins,
1164                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1165                         while (iter) {
1166                                 if (iter->fib6_metric > rt->fib6_metric)
1167                                         break;
1168                                 if (rt6_qualify_for_ecmp(iter)) {
1169                                         *ins = iter->fib6_next;
1170                                         iter->fib6_node = NULL;
1171                                         fib6_purge_rt(iter, fn, info->nl_net);
1172                                         if (rcu_access_pointer(fn->rr_ptr) == iter)
1173                                                 fn->rr_ptr = NULL;
1174                                         fib6_info_release(iter);
1175                                         nsiblings--;
1176                                         info->nl_net->ipv6.rt6_stats->fib_rt_entries--;
1177                                 } else {
1178                                         ins = &iter->fib6_next;
1179                                 }
1180                                 iter = rcu_dereference_protected(*ins,
1181                                         lockdep_is_held(&rt->fib6_table->tb6_lock));
1182                         }
1183                         WARN_ON(nsiblings != 0);
1184                 }
1185         }
1186
1187         return 0;
1188 }
1189
1190 static void fib6_start_gc(struct net *net, struct fib6_info *rt)
1191 {
1192         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
1193             (rt->fib6_flags & RTF_EXPIRES))
1194                 mod_timer(&net->ipv6.ip6_fib_timer,
1195                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1196 }
1197
1198 void fib6_force_start_gc(struct net *net)
1199 {
1200         if (!timer_pending(&net->ipv6.ip6_fib_timer))
1201                 mod_timer(&net->ipv6.ip6_fib_timer,
1202                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1203 }
1204
1205 static void __fib6_update_sernum_upto_root(struct fib6_info *rt,
1206                                            int sernum)
1207 {
1208         struct fib6_node *fn = rcu_dereference_protected(rt->fib6_node,
1209                                 lockdep_is_held(&rt->fib6_table->tb6_lock));
1210
1211         /* paired with smp_rmb() in rt6_get_cookie_safe() */
1212         smp_wmb();
1213         while (fn) {
1214                 fn->fn_sernum = sernum;
1215                 fn = rcu_dereference_protected(fn->parent,
1216                                 lockdep_is_held(&rt->fib6_table->tb6_lock));
1217         }
1218 }
1219
1220 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt)
1221 {
1222         __fib6_update_sernum_upto_root(rt, fib6_new_sernum(net));
1223 }
1224
1225 /* allow ipv4 to update sernum via ipv6_stub */
1226 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i)
1227 {
1228         spin_lock_bh(&f6i->fib6_table->tb6_lock);
1229         fib6_update_sernum_upto_root(net, f6i);
1230         spin_unlock_bh(&f6i->fib6_table->tb6_lock);
1231 }
1232
1233 /*
1234  *      Add routing information to the routing tree.
1235  *      <destination addr>/<source addr>
1236  *      with source addr info in sub-trees
1237  *      Need to own table->tb6_lock
1238  */
1239
1240 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
1241              struct nl_info *info, struct netlink_ext_ack *extack)
1242 {
1243         struct fib6_table *table = rt->fib6_table;
1244         struct fib6_node *fn, *pn = NULL;
1245         int err = -ENOMEM;
1246         int allow_create = 1;
1247         int replace_required = 0;
1248         int sernum = fib6_new_sernum(info->nl_net);
1249
1250         if (info->nlh) {
1251                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
1252                         allow_create = 0;
1253                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
1254                         replace_required = 1;
1255         }
1256         if (!allow_create && !replace_required)
1257                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
1258
1259         fn = fib6_add_1(info->nl_net, table, root,
1260                         &rt->fib6_dst.addr, rt->fib6_dst.plen,
1261                         offsetof(struct fib6_info, fib6_dst), allow_create,
1262                         replace_required, extack);
1263         if (IS_ERR(fn)) {
1264                 err = PTR_ERR(fn);
1265                 fn = NULL;
1266                 goto out;
1267         }
1268
1269         pn = fn;
1270
1271 #ifdef CONFIG_IPV6_SUBTREES
1272         if (rt->fib6_src.plen) {
1273                 struct fib6_node *sn;
1274
1275                 if (!rcu_access_pointer(fn->subtree)) {
1276                         struct fib6_node *sfn;
1277
1278                         /*
1279                          * Create subtree.
1280                          *
1281                          *              fn[main tree]
1282                          *              |
1283                          *              sfn[subtree root]
1284                          *                 \
1285                          *                  sn[new leaf node]
1286                          */
1287
1288                         /* Create subtree root node */
1289                         sfn = node_alloc(info->nl_net);
1290                         if (!sfn)
1291                                 goto failure;
1292
1293                         fib6_info_hold(info->nl_net->ipv6.fib6_null_entry);
1294                         rcu_assign_pointer(sfn->leaf,
1295                                            info->nl_net->ipv6.fib6_null_entry);
1296                         sfn->fn_flags = RTN_ROOT;
1297
1298                         /* Now add the first leaf node to new subtree */
1299
1300                         sn = fib6_add_1(info->nl_net, table, sfn,
1301                                         &rt->fib6_src.addr, rt->fib6_src.plen,
1302                                         offsetof(struct fib6_info, fib6_src),
1303                                         allow_create, replace_required, extack);
1304
1305                         if (IS_ERR(sn)) {
1306                                 /* If it is failed, discard just allocated
1307                                    root, and then (in failure) stale node
1308                                    in main tree.
1309                                  */
1310                                 node_free_immediate(info->nl_net, sfn);
1311                                 err = PTR_ERR(sn);
1312                                 goto failure;
1313                         }
1314
1315                         /* Now link new subtree to main tree */
1316                         rcu_assign_pointer(sfn->parent, fn);
1317                         rcu_assign_pointer(fn->subtree, sfn);
1318                 } else {
1319                         sn = fib6_add_1(info->nl_net, table, FIB6_SUBTREE(fn),
1320                                         &rt->fib6_src.addr, rt->fib6_src.plen,
1321                                         offsetof(struct fib6_info, fib6_src),
1322                                         allow_create, replace_required, extack);
1323
1324                         if (IS_ERR(sn)) {
1325                                 err = PTR_ERR(sn);
1326                                 goto failure;
1327                         }
1328                 }
1329
1330                 if (!rcu_access_pointer(fn->leaf)) {
1331                         if (fn->fn_flags & RTN_TL_ROOT) {
1332                                 /* put back null_entry for root node */
1333                                 rcu_assign_pointer(fn->leaf,
1334                                             info->nl_net->ipv6.fib6_null_entry);
1335                         } else {
1336                                 fib6_info_hold(rt);
1337                                 rcu_assign_pointer(fn->leaf, rt);
1338                         }
1339                 }
1340                 fn = sn;
1341         }
1342 #endif
1343
1344         err = fib6_add_rt2node(fn, rt, info, extack);
1345         if (!err) {
1346                 __fib6_update_sernum_upto_root(rt, sernum);
1347                 fib6_start_gc(info->nl_net, rt);
1348         }
1349
1350 out:
1351         if (err) {
1352 #ifdef CONFIG_IPV6_SUBTREES
1353                 /*
1354                  * If fib6_add_1 has cleared the old leaf pointer in the
1355                  * super-tree leaf node we have to find a new one for it.
1356                  */
1357                 if (pn != fn) {
1358                         struct fib6_info *pn_leaf =
1359                                 rcu_dereference_protected(pn->leaf,
1360                                     lockdep_is_held(&table->tb6_lock));
1361                         if (pn_leaf == rt) {
1362                                 pn_leaf = NULL;
1363                                 RCU_INIT_POINTER(pn->leaf, NULL);
1364                                 fib6_info_release(rt);
1365                         }
1366                         if (!pn_leaf && !(pn->fn_flags & RTN_RTINFO)) {
1367                                 pn_leaf = fib6_find_prefix(info->nl_net, table,
1368                                                            pn);
1369 #if RT6_DEBUG >= 2
1370                                 if (!pn_leaf) {
1371                                         WARN_ON(!pn_leaf);
1372                                         pn_leaf =
1373                                             info->nl_net->ipv6.fib6_null_entry;
1374                                 }
1375 #endif
1376                                 fib6_info_hold(pn_leaf);
1377                                 rcu_assign_pointer(pn->leaf, pn_leaf);
1378                         }
1379                 }
1380 #endif
1381                 goto failure;
1382         }
1383         return err;
1384
1385 failure:
1386         /* fn->leaf could be NULL and fib6_repair_tree() needs to be called if:
1387          * 1. fn is an intermediate node and we failed to add the new
1388          * route to it in both subtree creation failure and fib6_add_rt2node()
1389          * failure case.
1390          * 2. fn is the root node in the table and we fail to add the first
1391          * default route to it.
1392          */
1393         if (fn &&
1394             (!(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)) ||
1395              (fn->fn_flags & RTN_TL_ROOT &&
1396               !rcu_access_pointer(fn->leaf))))
1397                 fib6_repair_tree(info->nl_net, table, fn);
1398         return err;
1399 }
1400
1401 /*
1402  *      Routing tree lookup
1403  *
1404  */
1405
1406 struct lookup_args {
1407         int                     offset;         /* key offset on fib6_info */
1408         const struct in6_addr   *addr;          /* search key                   */
1409 };
1410
1411 static struct fib6_node *fib6_node_lookup_1(struct fib6_node *root,
1412                                             struct lookup_args *args)
1413 {
1414         struct fib6_node *fn;
1415         __be32 dir;
1416
1417         if (unlikely(args->offset == 0))
1418                 return NULL;
1419
1420         /*
1421          *      Descend on a tree
1422          */
1423
1424         fn = root;
1425
1426         for (;;) {
1427                 struct fib6_node *next;
1428
1429                 dir = addr_bit_set(args->addr, fn->fn_bit);
1430
1431                 next = dir ? rcu_dereference(fn->right) :
1432                              rcu_dereference(fn->left);
1433
1434                 if (next) {
1435                         fn = next;
1436                         continue;
1437                 }
1438                 break;
1439         }
1440
1441         while (fn) {
1442                 struct fib6_node *subtree = FIB6_SUBTREE(fn);
1443
1444                 if (subtree || fn->fn_flags & RTN_RTINFO) {
1445                         struct fib6_info *leaf = rcu_dereference(fn->leaf);
1446                         struct rt6key *key;
1447
1448                         if (!leaf)
1449                                 goto backtrack;
1450
1451                         key = (struct rt6key *) ((u8 *)leaf + args->offset);
1452
1453                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1454 #ifdef CONFIG_IPV6_SUBTREES
1455                                 if (subtree) {
1456                                         struct fib6_node *sfn;
1457                                         sfn = fib6_node_lookup_1(subtree,
1458                                                                  args + 1);
1459                                         if (!sfn)
1460                                                 goto backtrack;
1461                                         fn = sfn;
1462                                 }
1463 #endif
1464                                 if (fn->fn_flags & RTN_RTINFO)
1465                                         return fn;
1466                         }
1467                 }
1468 backtrack:
1469                 if (fn->fn_flags & RTN_ROOT)
1470                         break;
1471
1472                 fn = rcu_dereference(fn->parent);
1473         }
1474
1475         return NULL;
1476 }
1477
1478 /* called with rcu_read_lock() held
1479  */
1480 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
1481                                    const struct in6_addr *daddr,
1482                                    const struct in6_addr *saddr)
1483 {
1484         struct fib6_node *fn;
1485         struct lookup_args args[] = {
1486                 {
1487                         .offset = offsetof(struct fib6_info, fib6_dst),
1488                         .addr = daddr,
1489                 },
1490 #ifdef CONFIG_IPV6_SUBTREES
1491                 {
1492                         .offset = offsetof(struct fib6_info, fib6_src),
1493                         .addr = saddr,
1494                 },
1495 #endif
1496                 {
1497                         .offset = 0,    /* sentinel */
1498                 }
1499         };
1500
1501         fn = fib6_node_lookup_1(root, daddr ? args : args + 1);
1502         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1503                 fn = root;
1504
1505         return fn;
1506 }
1507
1508 /*
1509  *      Get node with specified destination prefix (and source prefix,
1510  *      if subtrees are used)
1511  *      exact_match == true means we try to find fn with exact match of
1512  *      the passed in prefix addr
1513  *      exact_match == false means we try to find fn with longest prefix
1514  *      match of the passed in prefix addr. This is useful for finding fn
1515  *      for cached route as it will be stored in the exception table under
1516  *      the node with longest prefix length.
1517  */
1518
1519
1520 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1521                                        const struct in6_addr *addr,
1522                                        int plen, int offset,
1523                                        bool exact_match)
1524 {
1525         struct fib6_node *fn, *prev = NULL;
1526
1527         for (fn = root; fn ; ) {
1528                 struct fib6_info *leaf = rcu_dereference(fn->leaf);
1529                 struct rt6key *key;
1530
1531                 /* This node is being deleted */
1532                 if (!leaf) {
1533                         if (plen <= fn->fn_bit)
1534                                 goto out;
1535                         else
1536                                 goto next;
1537                 }
1538
1539                 key = (struct rt6key *)((u8 *)leaf + offset);
1540
1541                 /*
1542                  *      Prefix match
1543                  */
1544                 if (plen < fn->fn_bit ||
1545                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1546                         goto out;
1547
1548                 if (plen == fn->fn_bit)
1549                         return fn;
1550
1551                 prev = fn;
1552
1553 next:
1554                 /*
1555                  *      We have more bits to go
1556                  */
1557                 if (addr_bit_set(addr, fn->fn_bit))
1558                         fn = rcu_dereference(fn->right);
1559                 else
1560                         fn = rcu_dereference(fn->left);
1561         }
1562 out:
1563         if (exact_match)
1564                 return NULL;
1565         else
1566                 return prev;
1567 }
1568
1569 struct fib6_node *fib6_locate(struct fib6_node *root,
1570                               const struct in6_addr *daddr, int dst_len,
1571                               const struct in6_addr *saddr, int src_len,
1572                               bool exact_match)
1573 {
1574         struct fib6_node *fn;
1575
1576         fn = fib6_locate_1(root, daddr, dst_len,
1577                            offsetof(struct fib6_info, fib6_dst),
1578                            exact_match);
1579
1580 #ifdef CONFIG_IPV6_SUBTREES
1581         if (src_len) {
1582                 WARN_ON(saddr == NULL);
1583                 if (fn) {
1584                         struct fib6_node *subtree = FIB6_SUBTREE(fn);
1585
1586                         if (subtree) {
1587                                 fn = fib6_locate_1(subtree, saddr, src_len,
1588                                            offsetof(struct fib6_info, fib6_src),
1589                                            exact_match);
1590                         }
1591                 }
1592         }
1593 #endif
1594
1595         if (fn && fn->fn_flags & RTN_RTINFO)
1596                 return fn;
1597
1598         return NULL;
1599 }
1600
1601
1602 /*
1603  *      Deletion
1604  *
1605  */
1606
1607 static struct fib6_info *fib6_find_prefix(struct net *net,
1608                                          struct fib6_table *table,
1609                                          struct fib6_node *fn)
1610 {
1611         struct fib6_node *child_left, *child_right;
1612
1613         if (fn->fn_flags & RTN_ROOT)
1614                 return net->ipv6.fib6_null_entry;
1615
1616         while (fn) {
1617                 child_left = rcu_dereference_protected(fn->left,
1618                                     lockdep_is_held(&table->tb6_lock));
1619                 child_right = rcu_dereference_protected(fn->right,
1620                                     lockdep_is_held(&table->tb6_lock));
1621                 if (child_left)
1622                         return rcu_dereference_protected(child_left->leaf,
1623                                         lockdep_is_held(&table->tb6_lock));
1624                 if (child_right)
1625                         return rcu_dereference_protected(child_right->leaf,
1626                                         lockdep_is_held(&table->tb6_lock));
1627
1628                 fn = FIB6_SUBTREE(fn);
1629         }
1630         return NULL;
1631 }
1632
1633 /*
1634  *      Called to trim the tree of intermediate nodes when possible. "fn"
1635  *      is the node we want to try and remove.
1636  *      Need to own table->tb6_lock
1637  */
1638
1639 static struct fib6_node *fib6_repair_tree(struct net *net,
1640                                           struct fib6_table *table,
1641                                           struct fib6_node *fn)
1642 {
1643         int children;
1644         int nstate;
1645         struct fib6_node *child;
1646         struct fib6_walker *w;
1647         int iter = 0;
1648
1649         /* Set fn->leaf to null_entry for root node. */
1650         if (fn->fn_flags & RTN_TL_ROOT) {
1651                 rcu_assign_pointer(fn->leaf, net->ipv6.fib6_null_entry);
1652                 return fn;
1653         }
1654
1655         for (;;) {
1656                 struct fib6_node *fn_r = rcu_dereference_protected(fn->right,
1657                                             lockdep_is_held(&table->tb6_lock));
1658                 struct fib6_node *fn_l = rcu_dereference_protected(fn->left,
1659                                             lockdep_is_held(&table->tb6_lock));
1660                 struct fib6_node *pn = rcu_dereference_protected(fn->parent,
1661                                             lockdep_is_held(&table->tb6_lock));
1662                 struct fib6_node *pn_r = rcu_dereference_protected(pn->right,
1663                                             lockdep_is_held(&table->tb6_lock));
1664                 struct fib6_node *pn_l = rcu_dereference_protected(pn->left,
1665                                             lockdep_is_held(&table->tb6_lock));
1666                 struct fib6_info *fn_leaf = rcu_dereference_protected(fn->leaf,
1667                                             lockdep_is_held(&table->tb6_lock));
1668                 struct fib6_info *pn_leaf = rcu_dereference_protected(pn->leaf,
1669                                             lockdep_is_held(&table->tb6_lock));
1670                 struct fib6_info *new_fn_leaf;
1671
1672                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1673                 iter++;
1674
1675                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1676                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1677                 WARN_ON(fn_leaf);
1678
1679                 children = 0;
1680                 child = NULL;
1681                 if (fn_r)
1682                         child = fn_r, children |= 1;
1683                 if (fn_l)
1684                         child = fn_l, children |= 2;
1685
1686                 if (children == 3 || FIB6_SUBTREE(fn)
1687 #ifdef CONFIG_IPV6_SUBTREES
1688                     /* Subtree root (i.e. fn) may have one child */
1689                     || (children && fn->fn_flags & RTN_ROOT)
1690 #endif
1691                     ) {
1692                         new_fn_leaf = fib6_find_prefix(net, table, fn);
1693 #if RT6_DEBUG >= 2
1694                         if (!new_fn_leaf) {
1695                                 WARN_ON(!new_fn_leaf);
1696                                 new_fn_leaf = net->ipv6.fib6_null_entry;
1697                         }
1698 #endif
1699                         fib6_info_hold(new_fn_leaf);
1700                         rcu_assign_pointer(fn->leaf, new_fn_leaf);
1701                         return pn;
1702                 }
1703
1704 #ifdef CONFIG_IPV6_SUBTREES
1705                 if (FIB6_SUBTREE(pn) == fn) {
1706                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1707                         RCU_INIT_POINTER(pn->subtree, NULL);
1708                         nstate = FWS_L;
1709                 } else {
1710                         WARN_ON(fn->fn_flags & RTN_ROOT);
1711 #endif
1712                         if (pn_r == fn)
1713                                 rcu_assign_pointer(pn->right, child);
1714                         else if (pn_l == fn)
1715                                 rcu_assign_pointer(pn->left, child);
1716 #if RT6_DEBUG >= 2
1717                         else
1718                                 WARN_ON(1);
1719 #endif
1720                         if (child)
1721                                 rcu_assign_pointer(child->parent, pn);
1722                         nstate = FWS_R;
1723 #ifdef CONFIG_IPV6_SUBTREES
1724                 }
1725 #endif
1726
1727                 read_lock(&net->ipv6.fib6_walker_lock);
1728                 FOR_WALKERS(net, w) {
1729                         if (!child) {
1730                                 if (w->node == fn) {
1731                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1732                                         w->node = pn;
1733                                         w->state = nstate;
1734                                 }
1735                         } else {
1736                                 if (w->node == fn) {
1737                                         w->node = child;
1738                                         if (children&2) {
1739                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1740                                                 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1741                                         } else {
1742                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1743                                                 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1744                                         }
1745                                 }
1746                         }
1747                 }
1748                 read_unlock(&net->ipv6.fib6_walker_lock);
1749
1750                 node_free(net, fn);
1751                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1752                         return pn;
1753
1754                 RCU_INIT_POINTER(pn->leaf, NULL);
1755                 fib6_info_release(pn_leaf);
1756                 fn = pn;
1757         }
1758 }
1759
1760 static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
1761                            struct fib6_info __rcu **rtp, struct nl_info *info)
1762 {
1763         struct fib6_walker *w;
1764         struct fib6_info *rt = rcu_dereference_protected(*rtp,
1765                                     lockdep_is_held(&table->tb6_lock));
1766         struct net *net = info->nl_net;
1767
1768         RT6_TRACE("fib6_del_route\n");
1769
1770         /* Unlink it */
1771         *rtp = rt->fib6_next;
1772         rt->fib6_node = NULL;
1773         net->ipv6.rt6_stats->fib_rt_entries--;
1774         net->ipv6.rt6_stats->fib_discarded_routes++;
1775
1776         /* Flush all cached dst in exception table */
1777         rt6_flush_exceptions(rt);
1778
1779         /* Reset round-robin state, if necessary */
1780         if (rcu_access_pointer(fn->rr_ptr) == rt)
1781                 fn->rr_ptr = NULL;
1782
1783         /* Remove this entry from other siblings */
1784         if (rt->fib6_nsiblings) {
1785                 struct fib6_info *sibling, *next_sibling;
1786
1787                 list_for_each_entry_safe(sibling, next_sibling,
1788                                          &rt->fib6_siblings, fib6_siblings)
1789                         sibling->fib6_nsiblings--;
1790                 rt->fib6_nsiblings = 0;
1791                 list_del_init(&rt->fib6_siblings);
1792                 rt6_multipath_rebalance(next_sibling);
1793         }
1794
1795         /* Adjust walkers */
1796         read_lock(&net->ipv6.fib6_walker_lock);
1797         FOR_WALKERS(net, w) {
1798                 if (w->state == FWS_C && w->leaf == rt) {
1799                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1800                         w->leaf = rcu_dereference_protected(rt->fib6_next,
1801                                             lockdep_is_held(&table->tb6_lock));
1802                         if (!w->leaf)
1803                                 w->state = FWS_U;
1804                 }
1805         }
1806         read_unlock(&net->ipv6.fib6_walker_lock);
1807
1808         /* If it was last route, call fib6_repair_tree() to:
1809          * 1. For root node, put back null_entry as how the table was created.
1810          * 2. For other nodes, expunge its radix tree node.
1811          */
1812         if (!rcu_access_pointer(fn->leaf)) {
1813                 if (!(fn->fn_flags & RTN_TL_ROOT)) {
1814                         fn->fn_flags &= ~RTN_RTINFO;
1815                         net->ipv6.rt6_stats->fib_route_nodes--;
1816                 }
1817                 fn = fib6_repair_tree(net, table, fn);
1818         }
1819
1820         fib6_purge_rt(rt, fn, net);
1821
1822         call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, rt, NULL);
1823         if (!info->skip_notify)
1824                 inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
1825         fib6_info_release(rt);
1826 }
1827
1828 /* Need to own table->tb6_lock */
1829 int fib6_del(struct fib6_info *rt, struct nl_info *info)
1830 {
1831         struct fib6_node *fn = rcu_dereference_protected(rt->fib6_node,
1832                                     lockdep_is_held(&rt->fib6_table->tb6_lock));
1833         struct fib6_table *table = rt->fib6_table;
1834         struct net *net = info->nl_net;
1835         struct fib6_info __rcu **rtp;
1836         struct fib6_info __rcu **rtp_next;
1837
1838         if (!fn || rt == net->ipv6.fib6_null_entry)
1839                 return -ENOENT;
1840
1841         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1842
1843         /*
1844          *      Walk the leaf entries looking for ourself
1845          */
1846
1847         for (rtp = &fn->leaf; *rtp; rtp = rtp_next) {
1848                 struct fib6_info *cur = rcu_dereference_protected(*rtp,
1849                                         lockdep_is_held(&table->tb6_lock));
1850                 if (rt == cur) {
1851                         fib6_del_route(table, fn, rtp, info);
1852                         return 0;
1853                 }
1854                 rtp_next = &cur->fib6_next;
1855         }
1856         return -ENOENT;
1857 }
1858
1859 /*
1860  *      Tree traversal function.
1861  *
1862  *      Certainly, it is not interrupt safe.
1863  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1864  *      It means, that we can modify tree during walking
1865  *      and use this function for garbage collection, clone pruning,
1866  *      cleaning tree when a device goes down etc. etc.
1867  *
1868  *      It guarantees that every node will be traversed,
1869  *      and that it will be traversed only once.
1870  *
1871  *      Callback function w->func may return:
1872  *      0 -> continue walking.
1873  *      positive value -> walking is suspended (used by tree dumps,
1874  *      and probably by gc, if it will be split to several slices)
1875  *      negative value -> terminate walking.
1876  *
1877  *      The function itself returns:
1878  *      0   -> walk is complete.
1879  *      >0  -> walk is incomplete (i.e. suspended)
1880  *      <0  -> walk is terminated by an error.
1881  *
1882  *      This function is called with tb6_lock held.
1883  */
1884
1885 static int fib6_walk_continue(struct fib6_walker *w)
1886 {
1887         struct fib6_node *fn, *pn, *left, *right;
1888
1889         /* w->root should always be table->tb6_root */
1890         WARN_ON_ONCE(!(w->root->fn_flags & RTN_TL_ROOT));
1891
1892         for (;;) {
1893                 fn = w->node;
1894                 if (!fn)
1895                         return 0;
1896
1897                 switch (w->state) {
1898 #ifdef CONFIG_IPV6_SUBTREES
1899                 case FWS_S:
1900                         if (FIB6_SUBTREE(fn)) {
1901                                 w->node = FIB6_SUBTREE(fn);
1902                                 continue;
1903                         }
1904                         w->state = FWS_L;
1905 #endif
1906                         /* fall through */
1907                 case FWS_L:
1908                         left = rcu_dereference_protected(fn->left, 1);
1909                         if (left) {
1910                                 w->node = left;
1911                                 w->state = FWS_INIT;
1912                                 continue;
1913                         }
1914                         w->state = FWS_R;
1915                         /* fall through */
1916                 case FWS_R:
1917                         right = rcu_dereference_protected(fn->right, 1);
1918                         if (right) {
1919                                 w->node = right;
1920                                 w->state = FWS_INIT;
1921                                 continue;
1922                         }
1923                         w->state = FWS_C;
1924                         w->leaf = rcu_dereference_protected(fn->leaf, 1);
1925                         /* fall through */
1926                 case FWS_C:
1927                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1928                                 int err;
1929
1930                                 if (w->skip) {
1931                                         w->skip--;
1932                                         goto skip;
1933                                 }
1934
1935                                 err = w->func(w);
1936                                 if (err)
1937                                         return err;
1938
1939                                 w->count++;
1940                                 continue;
1941                         }
1942 skip:
1943                         w->state = FWS_U;
1944                         /* fall through */
1945                 case FWS_U:
1946                         if (fn == w->root)
1947                                 return 0;
1948                         pn = rcu_dereference_protected(fn->parent, 1);
1949                         left = rcu_dereference_protected(pn->left, 1);
1950                         right = rcu_dereference_protected(pn->right, 1);
1951                         w->node = pn;
1952 #ifdef CONFIG_IPV6_SUBTREES
1953                         if (FIB6_SUBTREE(pn) == fn) {
1954                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1955                                 w->state = FWS_L;
1956                                 continue;
1957                         }
1958 #endif
1959                         if (left == fn) {
1960                                 w->state = FWS_R;
1961                                 continue;
1962                         }
1963                         if (right == fn) {
1964                                 w->state = FWS_C;
1965                                 w->leaf = rcu_dereference_protected(w->node->leaf, 1);
1966                                 continue;
1967                         }
1968 #if RT6_DEBUG >= 2
1969                         WARN_ON(1);
1970 #endif
1971                 }
1972         }
1973 }
1974
1975 static int fib6_walk(struct net *net, struct fib6_walker *w)
1976 {
1977         int res;
1978
1979         w->state = FWS_INIT;
1980         w->node = w->root;
1981
1982         fib6_walker_link(net, w);
1983         res = fib6_walk_continue(w);
1984         if (res <= 0)
1985                 fib6_walker_unlink(net, w);
1986         return res;
1987 }
1988
1989 static int fib6_clean_node(struct fib6_walker *w)
1990 {
1991         int res;
1992         struct fib6_info *rt;
1993         struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
1994         struct nl_info info = {
1995                 .nl_net = c->net,
1996                 .skip_notify = c->skip_notify,
1997         };
1998
1999         if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
2000             w->node->fn_sernum != c->sernum)
2001                 w->node->fn_sernum = c->sernum;
2002
2003         if (!c->func) {
2004                 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
2005                 w->leaf = NULL;
2006                 return 0;
2007         }
2008
2009         for_each_fib6_walker_rt(w) {
2010                 res = c->func(rt, c->arg);
2011                 if (res == -1) {
2012                         w->leaf = rt;
2013                         res = fib6_del(rt, &info);
2014                         if (res) {
2015 #if RT6_DEBUG >= 2
2016                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
2017                                          __func__, rt,
2018                                          rcu_access_pointer(rt->fib6_node),
2019                                          res);
2020 #endif
2021                                 continue;
2022                         }
2023                         return 0;
2024                 } else if (res == -2) {
2025                         if (WARN_ON(!rt->fib6_nsiblings))
2026                                 continue;
2027                         rt = list_last_entry(&rt->fib6_siblings,
2028                                              struct fib6_info, fib6_siblings);
2029                         continue;
2030                 }
2031                 WARN_ON(res != 0);
2032         }
2033         w->leaf = rt;
2034         return 0;
2035 }
2036
2037 /*
2038  *      Convenient frontend to tree walker.
2039  *
2040  *      func is called on each route.
2041  *              It may return -2 -> skip multipath route.
2042  *                            -1 -> delete this route.
2043  *                            0  -> continue walking
2044  */
2045
2046 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
2047                             int (*func)(struct fib6_info *, void *arg),
2048                             int sernum, void *arg, bool skip_notify)
2049 {
2050         struct fib6_cleaner c;
2051
2052         c.w.root = root;
2053         c.w.func = fib6_clean_node;
2054         c.w.count = 0;
2055         c.w.skip = 0;
2056         c.func = func;
2057         c.sernum = sernum;
2058         c.arg = arg;
2059         c.net = net;
2060         c.skip_notify = skip_notify;
2061
2062         fib6_walk(net, &c.w);
2063 }
2064
2065 static void __fib6_clean_all(struct net *net,
2066                              int (*func)(struct fib6_info *, void *),
2067                              int sernum, void *arg, bool skip_notify)
2068 {
2069         struct fib6_table *table;
2070         struct hlist_head *head;
2071         unsigned int h;
2072
2073         rcu_read_lock();
2074         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
2075                 head = &net->ipv6.fib_table_hash[h];
2076                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
2077                         spin_lock_bh(&table->tb6_lock);
2078                         fib6_clean_tree(net, &table->tb6_root,
2079                                         func, sernum, arg, skip_notify);
2080                         spin_unlock_bh(&table->tb6_lock);
2081                 }
2082         }
2083         rcu_read_unlock();
2084 }
2085
2086 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *),
2087                     void *arg)
2088 {
2089         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, false);
2090 }
2091
2092 void fib6_clean_all_skip_notify(struct net *net,
2093                                 int (*func)(struct fib6_info *, void *),
2094                                 void *arg)
2095 {
2096         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, true);
2097 }
2098
2099 static void fib6_flush_trees(struct net *net)
2100 {
2101         int new_sernum = fib6_new_sernum(net);
2102
2103         __fib6_clean_all(net, NULL, new_sernum, NULL, false);
2104 }
2105
2106 /*
2107  *      Garbage collection
2108  */
2109
2110 static int fib6_age(struct fib6_info *rt, void *arg)
2111 {
2112         struct fib6_gc_args *gc_args = arg;
2113         unsigned long now = jiffies;
2114
2115         /*
2116          *      check addrconf expiration here.
2117          *      Routes are expired even if they are in use.
2118          */
2119
2120         if (rt->fib6_flags & RTF_EXPIRES && rt->expires) {
2121                 if (time_after(now, rt->expires)) {
2122                         RT6_TRACE("expiring %p\n", rt);
2123                         return -1;
2124                 }
2125                 gc_args->more++;
2126         }
2127
2128         /*      Also age clones in the exception table.
2129          *      Note, that clones are aged out
2130          *      only if they are not in use now.
2131          */
2132         rt6_age_exceptions(rt, gc_args, now);
2133
2134         return 0;
2135 }
2136
2137 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
2138 {
2139         struct fib6_gc_args gc_args;
2140         unsigned long now;
2141
2142         if (force) {
2143                 spin_lock_bh(&net->ipv6.fib6_gc_lock);
2144         } else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
2145                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
2146                 return;
2147         }
2148         gc_args.timeout = expires ? (int)expires :
2149                           net->ipv6.sysctl.ip6_rt_gc_interval;
2150         gc_args.more = 0;
2151
2152         fib6_clean_all(net, fib6_age, &gc_args);
2153         now = jiffies;
2154         net->ipv6.ip6_rt_last_gc = now;
2155
2156         if (gc_args.more)
2157                 mod_timer(&net->ipv6.ip6_fib_timer,
2158                           round_jiffies(now
2159                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
2160         else
2161                 del_timer(&net->ipv6.ip6_fib_timer);
2162         spin_unlock_bh(&net->ipv6.fib6_gc_lock);
2163 }
2164
2165 static void fib6_gc_timer_cb(struct timer_list *t)
2166 {
2167         struct net *arg = from_timer(arg, t, ipv6.ip6_fib_timer);
2168
2169         fib6_run_gc(0, arg, true);
2170 }
2171
2172 static int __net_init fib6_net_init(struct net *net)
2173 {
2174         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
2175         int err;
2176
2177         err = fib6_notifier_init(net);
2178         if (err)
2179                 return err;
2180
2181         spin_lock_init(&net->ipv6.fib6_gc_lock);
2182         rwlock_init(&net->ipv6.fib6_walker_lock);
2183         INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
2184         timer_setup(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, 0);
2185
2186         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
2187         if (!net->ipv6.rt6_stats)
2188                 goto out_timer;
2189
2190         /* Avoid false sharing : Use at least a full cache line */
2191         size = max_t(size_t, size, L1_CACHE_BYTES);
2192
2193         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
2194         if (!net->ipv6.fib_table_hash)
2195                 goto out_rt6_stats;
2196
2197         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
2198                                           GFP_KERNEL);
2199         if (!net->ipv6.fib6_main_tbl)
2200                 goto out_fib_table_hash;
2201
2202         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
2203         rcu_assign_pointer(net->ipv6.fib6_main_tbl->tb6_root.leaf,
2204                            net->ipv6.fib6_null_entry);
2205         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
2206                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2207         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
2208
2209 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2210         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
2211                                            GFP_KERNEL);
2212         if (!net->ipv6.fib6_local_tbl)
2213                 goto out_fib6_main_tbl;
2214         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
2215         rcu_assign_pointer(net->ipv6.fib6_local_tbl->tb6_root.leaf,
2216                            net->ipv6.fib6_null_entry);
2217         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
2218                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2219         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
2220 #endif
2221         fib6_tables_init(net);
2222
2223         return 0;
2224
2225 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2226 out_fib6_main_tbl:
2227         kfree(net->ipv6.fib6_main_tbl);
2228 #endif
2229 out_fib_table_hash:
2230         kfree(net->ipv6.fib_table_hash);
2231 out_rt6_stats:
2232         kfree(net->ipv6.rt6_stats);
2233 out_timer:
2234         fib6_notifier_exit(net);
2235         return -ENOMEM;
2236 }
2237
2238 static void fib6_net_exit(struct net *net)
2239 {
2240         unsigned int i;
2241
2242         del_timer_sync(&net->ipv6.ip6_fib_timer);
2243
2244         for (i = 0; i < FIB6_TABLE_HASHSZ; i++) {
2245                 struct hlist_head *head = &net->ipv6.fib_table_hash[i];
2246                 struct hlist_node *tmp;
2247                 struct fib6_table *tb;
2248
2249                 hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
2250                         hlist_del(&tb->tb6_hlist);
2251                         fib6_free_table(tb);
2252                 }
2253         }
2254
2255         kfree(net->ipv6.fib_table_hash);
2256         kfree(net->ipv6.rt6_stats);
2257         fib6_notifier_exit(net);
2258 }
2259
2260 static struct pernet_operations fib6_net_ops = {
2261         .init = fib6_net_init,
2262         .exit = fib6_net_exit,
2263 };
2264
2265 int __init fib6_init(void)
2266 {
2267         int ret = -ENOMEM;
2268
2269         fib6_node_kmem = kmem_cache_create("fib6_nodes",
2270                                            sizeof(struct fib6_node),
2271                                            0, SLAB_HWCACHE_ALIGN,
2272                                            NULL);
2273         if (!fib6_node_kmem)
2274                 goto out;
2275
2276         ret = register_pernet_subsys(&fib6_net_ops);
2277         if (ret)
2278                 goto out_kmem_cache_create;
2279
2280         ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETROUTE, NULL,
2281                                    inet6_dump_fib, 0);
2282         if (ret)
2283                 goto out_unregister_subsys;
2284
2285         __fib6_flush_trees = fib6_flush_trees;
2286 out:
2287         return ret;
2288
2289 out_unregister_subsys:
2290         unregister_pernet_subsys(&fib6_net_ops);
2291 out_kmem_cache_create:
2292         kmem_cache_destroy(fib6_node_kmem);
2293         goto out;
2294 }
2295
2296 void fib6_gc_cleanup(void)
2297 {
2298         unregister_pernet_subsys(&fib6_net_ops);
2299         kmem_cache_destroy(fib6_node_kmem);
2300 }
2301
2302 #ifdef CONFIG_PROC_FS
2303 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2304 {
2305         struct fib6_info *rt = v;
2306         struct ipv6_route_iter *iter = seq->private;
2307         unsigned int flags = rt->fib6_flags;
2308         const struct net_device *dev;
2309
2310         seq_printf(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen);
2311
2312 #ifdef CONFIG_IPV6_SUBTREES
2313         seq_printf(seq, "%pi6 %02x ", &rt->fib6_src.addr, rt->fib6_src.plen);
2314 #else
2315         seq_puts(seq, "00000000000000000000000000000000 00 ");
2316 #endif
2317         if (rt->fib6_nh.fib_nh_gw_family) {
2318                 flags |= RTF_GATEWAY;
2319                 seq_printf(seq, "%pi6", &rt->fib6_nh.fib_nh_gw6);
2320         } else {
2321                 seq_puts(seq, "00000000000000000000000000000000");
2322         }
2323
2324         dev = rt->fib6_nh.fib_nh_dev;
2325         seq_printf(seq, " %08x %08x %08x %08x %8s\n",
2326                    rt->fib6_metric, refcount_read(&rt->fib6_ref), 0,
2327                    flags, dev ? dev->name : "");
2328         iter->w.leaf = NULL;
2329         return 0;
2330 }
2331
2332 static int ipv6_route_yield(struct fib6_walker *w)
2333 {
2334         struct ipv6_route_iter *iter = w->args;
2335
2336         if (!iter->skip)
2337                 return 1;
2338
2339         do {
2340                 iter->w.leaf = rcu_dereference_protected(
2341                                 iter->w.leaf->fib6_next,
2342                                 lockdep_is_held(&iter->tbl->tb6_lock));
2343                 iter->skip--;
2344                 if (!iter->skip && iter->w.leaf)
2345                         return 1;
2346         } while (iter->w.leaf);
2347
2348         return 0;
2349 }
2350
2351 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
2352                                       struct net *net)
2353 {
2354         memset(&iter->w, 0, sizeof(iter->w));
2355         iter->w.func = ipv6_route_yield;
2356         iter->w.root = &iter->tbl->tb6_root;
2357         iter->w.state = FWS_INIT;
2358         iter->w.node = iter->w.root;
2359         iter->w.args = iter;
2360         iter->sernum = iter->w.root->fn_sernum;
2361         INIT_LIST_HEAD(&iter->w.lh);
2362         fib6_walker_link(net, &iter->w);
2363 }
2364
2365 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
2366                                                     struct net *net)
2367 {
2368         unsigned int h;
2369         struct hlist_node *node;
2370
2371         if (tbl) {
2372                 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
2373                 node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
2374         } else {
2375                 h = 0;
2376                 node = NULL;
2377         }
2378
2379         while (!node && h < FIB6_TABLE_HASHSZ) {
2380                 node = rcu_dereference_bh(
2381                         hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
2382         }
2383         return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
2384 }
2385
2386 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
2387 {
2388         if (iter->sernum != iter->w.root->fn_sernum) {
2389                 iter->sernum = iter->w.root->fn_sernum;
2390                 iter->w.state = FWS_INIT;
2391                 iter->w.node = iter->w.root;
2392                 WARN_ON(iter->w.skip);
2393                 iter->w.skip = iter->w.count;
2394         }
2395 }
2396
2397 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2398 {
2399         int r;
2400         struct fib6_info *n;
2401         struct net *net = seq_file_net(seq);
2402         struct ipv6_route_iter *iter = seq->private;
2403
2404         if (!v)
2405                 goto iter_table;
2406
2407         n = rcu_dereference_bh(((struct fib6_info *)v)->fib6_next);
2408         if (n) {
2409                 ++*pos;
2410                 return n;
2411         }
2412
2413 iter_table:
2414         ipv6_route_check_sernum(iter);
2415         spin_lock_bh(&iter->tbl->tb6_lock);
2416         r = fib6_walk_continue(&iter->w);
2417         spin_unlock_bh(&iter->tbl->tb6_lock);
2418         if (r > 0) {
2419                 if (v)
2420                         ++*pos;
2421                 return iter->w.leaf;
2422         } else if (r < 0) {
2423                 fib6_walker_unlink(net, &iter->w);
2424                 return NULL;
2425         }
2426         fib6_walker_unlink(net, &iter->w);
2427
2428         iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
2429         if (!iter->tbl)
2430                 return NULL;
2431
2432         ipv6_route_seq_setup_walk(iter, net);
2433         goto iter_table;
2434 }
2435
2436 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
2437         __acquires(RCU_BH)
2438 {
2439         struct net *net = seq_file_net(seq);
2440         struct ipv6_route_iter *iter = seq->private;
2441
2442         rcu_read_lock_bh();
2443         iter->tbl = ipv6_route_seq_next_table(NULL, net);
2444         iter->skip = *pos;
2445
2446         if (iter->tbl) {
2447                 ipv6_route_seq_setup_walk(iter, net);
2448                 return ipv6_route_seq_next(seq, NULL, pos);
2449         } else {
2450                 return NULL;
2451         }
2452 }
2453
2454 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
2455 {
2456         struct fib6_walker *w = &iter->w;
2457         return w->node && !(w->state == FWS_U && w->node == w->root);
2458 }
2459
2460 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2461         __releases(RCU_BH)
2462 {
2463         struct net *net = seq_file_net(seq);
2464         struct ipv6_route_iter *iter = seq->private;
2465
2466         if (ipv6_route_iter_active(iter))
2467                 fib6_walker_unlink(net, &iter->w);
2468
2469         rcu_read_unlock_bh();
2470 }
2471
2472 const struct seq_operations ipv6_route_seq_ops = {
2473         .start  = ipv6_route_seq_start,
2474         .next   = ipv6_route_seq_next,
2475         .stop   = ipv6_route_seq_stop,
2476         .show   = ipv6_route_seq_show
2477 };
2478 #endif /* CONFIG_PROC_FS */