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/ipv6.h>
  33 #include <net/ndisc.h>
  34 #include <net/addrconf.h>
  35 #include <net/lwtunnel.h>
  36
  37 #include <net/ip6_fib.h>
  38 #include <net/ip6_route.h>
  39
  40 #define RT6_DEBUG 2
  41
  42 #if RT6_DEBUG >= 3
  43 #define RT6_TRACE(x...) pr_debug(x)
  44 #else
  45 #define RT6_TRACE(x...) do { ; } while (0)
  46 #endif
  47
  48 static struct kmem_cache *fib6_node_kmem __read_mostly;
  49
  50 struct fib6_cleaner {
  51         struct fib6_walker w;
  52         struct net *net;
  53         int (*func)(struct rt6_info *, void *arg);
  54         int sernum;
  55         void *arg;
  56 };
  57
  58 #ifdef CONFIG_IPV6_SUBTREES
  59 #define FWS_INIT FWS_S
  60 #else
  61 #define FWS_INIT FWS_L
  62 #endif
  63
  64 static void fib6_prune_clones(struct net *net, struct fib6_node *fn);
  65 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
  66 static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
  67 static int fib6_walk(struct net *net, struct fib6_walker *w);
  68 static int fib6_walk_continue(struct fib6_walker *w);
  69
  70 /*
  71  *      A routing update causes an increase of the serial number on the
  72  *      affected subtree. This allows for cached routes to be asynchronously
  73  *      tested when modifications are made to the destination cache as a
  74  *      result of redirects, path MTU changes, etc.
  75  */
  76
  77 static void fib6_gc_timer_cb(unsigned long arg);
  78
  79 #define FOR_WALKERS(net, w) \
  80         list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)
  81
  82 static void fib6_walker_link(struct net *net, struct fib6_walker *w)
  83 {
  84         write_lock_bh(&net->ipv6.fib6_walker_lock);
  85         list_add(&w->lh, &net->ipv6.fib6_walkers);
  86         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  87 }
  88
  89 static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
  90 {
  91         write_lock_bh(&net->ipv6.fib6_walker_lock);
  92         list_del(&w->lh);
  93         write_unlock_bh(&net->ipv6.fib6_walker_lock);
  94 }
  95
  96 static int fib6_new_sernum(struct net *net)
  97 {
  98         int new, old;
  99
 100         do {
 101                 old = atomic_read(&net->ipv6.fib6_sernum);
 102                 new = old < INT_MAX ? old + 1 : 1;
 103         } while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
 104                                 old, new) != old);
 105         return new;
 106 }
 107
 108 enum {
 109         FIB6_NO_SERNUM_CHANGE = 0,
 110 };
 111
 112 /*
 113  *      Auxiliary address test functions for the radix tree.
 114  *
 115  *      These assume a 32bit processor (although it will work on
 116  *      64bit processors)
 117  */
 118
 119 /*
 120  *      test bit
 121  */
 122 #if defined(__LITTLE_ENDIAN)
 123 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
 124 #else
 125 # define BITOP_BE32_SWIZZLE     0
 126 #endif
 127
 128 static __be32 addr_bit_set(const void *token, int fn_bit)
 129 {
 130         const __be32 *addr = token;
 131         /*
 132          * Here,
 133          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
 134          * is optimized version of
 135          *      htonl(1 << ((~fn_bit)&0x1F))
 136          * See include/asm-generic/bitops/le.h.
 137          */
 138         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
 139                addr[fn_bit >> 5];
 140 }
 141
 142 static struct fib6_node *node_alloc(void)
 143 {
 144         struct fib6_node *fn;
 145
 146         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 147
 148         return fn;
 149 }
 150
 151 static void node_free(struct fib6_node *fn)
 152 {
 153         kmem_cache_free(fib6_node_kmem, fn);
 154 }
 155
 156 static void rt6_rcu_free(struct rt6_info *rt)
 157 {
 158         call_rcu(&rt->dst.rcu_head, dst_rcu_free);
 159 }
 160
 161 static void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
 162 {
 163         int cpu;
 164
 165         if (!non_pcpu_rt->rt6i_pcpu)
 166                 return;
 167
 168         for_each_possible_cpu(cpu) {
 169                 struct rt6_info **ppcpu_rt;
 170                 struct rt6_info *pcpu_rt;
 171
 172                 ppcpu_rt = per_cpu_ptr(non_pcpu_rt->rt6i_pcpu, cpu);
 173                 pcpu_rt = *ppcpu_rt;
 174                 if (pcpu_rt) {
 175                         rt6_rcu_free(pcpu_rt);
 176                         *ppcpu_rt = NULL;
 177                 }
 178         }
 179
 180         non_pcpu_rt->rt6i_pcpu = NULL;
 181 }
 182
 183 static void rt6_release(struct rt6_info *rt)
 184 {
 185         if (atomic_dec_and_test(&rt->rt6i_ref)) {
 186                 rt6_free_pcpu(rt);
 187                 rt6_rcu_free(rt);
 188         }
 189 }
 190
 191 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 192 {
 193         unsigned int h;
 194
 195         /*
 196          * Initialize table lock at a single place to give lockdep a key,
 197          * tables aren't visible prior to being linked to the list.
 198          */
 199         rwlock_init(&tb->tb6_lock);
 200
 201         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 202
 203         /*
 204          * No protection necessary, this is the only list mutatation
 205          * operation, tables never disappear once they exist.
 206          */
 207         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 208 }
 209
 210 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 211
 212 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 213 {
 214         struct fib6_table *table;
 215
 216         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 217         if (table) {
 218                 table->tb6_id = id;
 219                 table->tb6_root.leaf = net->ipv6.ip6_null_entry;
 220                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 221                 inet_peer_base_init(&table->tb6_peers);
 222         }
 223
 224         return table;
 225 }
 226
 227 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 228 {
 229         struct fib6_table *tb;
 230
 231         if (id == 0)
 232                 id = RT6_TABLE_MAIN;
 233         tb = fib6_get_table(net, id);
 234         if (tb)
 235                 return tb;
 236
 237         tb = fib6_alloc_table(net, id);
 238         if (tb)
 239                 fib6_link_table(net, tb);
 240
 241         return tb;
 242 }
 243 EXPORT_SYMBOL_GPL(fib6_new_table);
 244
 245 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 246 {
 247         struct fib6_table *tb;
 248         struct hlist_head *head;
 249         unsigned int h;
 250
 251         if (id == 0)
 252                 id = RT6_TABLE_MAIN;
 253         h = id & (FIB6_TABLE_HASHSZ - 1);
 254         rcu_read_lock();
 255         head = &net->ipv6.fib_table_hash[h];
 256         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 257                 if (tb->tb6_id == id) {
 258                         rcu_read_unlock();
 259                         return tb;
 260                 }
 261         }
 262         rcu_read_unlock();
 263
 264         return NULL;
 265 }
 266 EXPORT_SYMBOL_GPL(fib6_get_table);
 267
 268 static void __net_init fib6_tables_init(struct net *net)
 269 {
 270         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 271         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 272 }
 273 #else
 274
 275 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 276 {
 277         return fib6_get_table(net, id);
 278 }
 279
 280 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 281 {
 282           return net->ipv6.fib6_main_tbl;
 283 }
 284
 285 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 286                                    int flags, pol_lookup_t lookup)
 287 {
 288         struct rt6_info *rt;
 289
 290         rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
 291         if (rt->rt6i_flags & RTF_REJECT &&
 292             rt->dst.error == -EAGAIN) {
 293                 ip6_rt_put(rt);
 294                 rt = net->ipv6.ip6_null_entry;
 295                 dst_hold(&rt->dst);
 296         }
 297
 298         return &rt->dst;
 299 }
 300
 301 static void __net_init fib6_tables_init(struct net *net)
 302 {
 303         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 304 }
 305
 306 #endif
 307
 308 static int fib6_dump_node(struct fib6_walker *w)
 309 {
 310         int res;
 311         struct rt6_info *rt;
 312
 313         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
 314                 res = rt6_dump_route(rt, w->args);
 315                 if (res < 0) {
 316                         /* Frame is full, suspend walking */
 317                         w->leaf = rt;
 318                         return 1;
 319                 }
 320         }
 321         w->leaf = NULL;
 322         return 0;
 323 }
 324
 325 static void fib6_dump_end(struct netlink_callback *cb)
 326 {
 327         struct net *net = sock_net(cb->skb->sk);
 328         struct fib6_walker *w = (void *)cb->args[2];
 329
 330         if (w) {
 331                 if (cb->args[4]) {
 332                         cb->args[4] = 0;
 333                         fib6_walker_unlink(net, w);
 334                 }
 335                 cb->args[2] = 0;
 336                 kfree(w);
 337         }
 338         cb->done = (void *)cb->args[3];
 339         cb->args[1] = 3;
 340 }
 341
 342 static int fib6_dump_done(struct netlink_callback *cb)
 343 {
 344         fib6_dump_end(cb);
 345         return cb->done ? cb->done(cb) : 0;
 346 }
 347
 348 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 349                            struct netlink_callback *cb)
 350 {
 351         struct net *net = sock_net(skb->sk);
 352         struct fib6_walker *w;
 353         int res;
 354
 355         w = (void *)cb->args[2];
 356         w->root = &table->tb6_root;
 357
 358         if (cb->args[4] == 0) {
 359                 w->count = 0;
 360                 w->skip = 0;
 361
 362                 read_lock_bh(&table->tb6_lock);
 363                 res = fib6_walk(net, w);
 364                 read_unlock_bh(&table->tb6_lock);
 365                 if (res > 0) {
 366                         cb->args[4] = 1;
 367                         cb->args[5] = w->root->fn_sernum;
 368                 }
 369         } else {
 370                 if (cb->args[5] != w->root->fn_sernum) {
 371                         /* Begin at the root if the tree changed */
 372                         cb->args[5] = w->root->fn_sernum;
 373                         w->state = FWS_INIT;
 374                         w->node = w->root;
 375                         w->skip = w->count;
 376                 } else
 377                         w->skip = 0;
 378
 379                 read_lock_bh(&table->tb6_lock);
 380                 res = fib6_walk_continue(w);
 381                 read_unlock_bh(&table->tb6_lock);
 382                 if (res <= 0) {
 383                         fib6_walker_unlink(net, w);
 384                         cb->args[4] = 0;
 385                 }
 386         }
 387
 388         return res;
 389 }
 390
 391 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 392 {
 393         struct net *net = sock_net(skb->sk);
 394         unsigned int h, s_h;
 395         unsigned int e = 0, s_e;
 396         struct rt6_rtnl_dump_arg arg;
 397         struct fib6_walker *w;
 398         struct fib6_table *tb;
 399         struct hlist_head *head;
 400         int res = 0;
 401
 402         s_h = cb->args[0];
 403         s_e = cb->args[1];
 404
 405         w = (void *)cb->args[2];
 406         if (!w) {
 407                 /* New dump:
 408                  *
 409                  * 1. hook callback destructor.
 410                  */
 411                 cb->args[3] = (long)cb->done;
 412                 cb->done = fib6_dump_done;
 413
 414                 /*
 415                  * 2. allocate and initialize walker.
 416                  */
 417                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 418                 if (!w)
 419                         return -ENOMEM;
 420                 w->func = fib6_dump_node;
 421                 cb->args[2] = (long)w;
 422         }
 423
 424         arg.skb = skb;
 425         arg.cb = cb;
 426         arg.net = net;
 427         w->args = &arg;
 428
 429         rcu_read_lock();
 430         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 431                 e = 0;
 432                 head = &net->ipv6.fib_table_hash[h];
 433                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 434                         if (e < s_e)
 435                                 goto next;
 436                         res = fib6_dump_table(tb, skb, cb);
 437                         if (res != 0)
 438                                 goto out;
 439 next:
 440                         e++;
 441                 }
 442         }
 443 out:
 444         rcu_read_unlock();
 445         cb->args[1] = e;
 446         cb->args[0] = h;
 447
 448         res = res < 0 ? res : skb->len;
 449         if (res <= 0)
 450                 fib6_dump_end(cb);
 451         return res;
 452 }
 453
 454 /*
 455  *      Routing Table
 456  *
 457  *      return the appropriate node for a routing tree "add" operation
 458  *      by either creating and inserting or by returning an existing
 459  *      node.
 460  */
 461
 462 static struct fib6_node *fib6_add_1(struct fib6_node *root,
 463                                      struct in6_addr *addr, int plen,
 464                                      int offset, int allow_create,
 465                                      int replace_required, int sernum)
 466 {
 467         struct fib6_node *fn, *in, *ln;
 468         struct fib6_node *pn = NULL;
 469         struct rt6key *key;
 470         int     bit;
 471         __be32  dir = 0;
 472
 473         RT6_TRACE("fib6_add_1\n");
 474
 475         /* insert node in tree */
 476
 477         fn = root;
 478
 479         do {
 480                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
 481
 482                 /*
 483                  *      Prefix match
 484                  */
 485                 if (plen < fn->fn_bit ||
 486                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 487                         if (!allow_create) {
 488                                 if (replace_required) {
 489                                         pr_warn("Can't replace route, no match found\n");
 490                                         return ERR_PTR(-ENOENT);
 491                                 }
 492                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 493                         }
 494                         goto insert_above;
 495                 }
 496
 497                 /*
 498                  *      Exact match ?
 499                  */
 500
 501                 if (plen == fn->fn_bit) {
 502                         /* clean up an intermediate node */
 503                         if (!(fn->fn_flags & RTN_RTINFO)) {
 504                                 rt6_release(fn->leaf);
 505                                 fn->leaf = NULL;
 506                         }
 507
 508                         fn->fn_sernum = sernum;
 509
 510                         return fn;
 511                 }
 512
 513                 /*
 514                  *      We have more bits to go
 515                  */
 516
 517                 /* Try to walk down on tree. */
 518                 fn->fn_sernum = sernum;
 519                 dir = addr_bit_set(addr, fn->fn_bit);
 520                 pn = fn;
 521                 fn = dir ? fn->right : fn->left;
 522         } while (fn);
 523
 524         if (!allow_create) {
 525                 /* We should not create new node because
 526                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 527                  * I assume it is safe to require NLM_F_CREATE when
 528                  * REPLACE flag is used! Later we may want to remove the
 529                  * check for replace_required, because according
 530                  * to netlink specification, NLM_F_CREATE
 531                  * MUST be specified if new route is created.
 532                  * That would keep IPv6 consistent with IPv4
 533                  */
 534                 if (replace_required) {
 535                         pr_warn("Can't replace route, no match found\n");
 536                         return ERR_PTR(-ENOENT);
 537                 }
 538                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 539         }
 540         /*
 541          *      We walked to the bottom of tree.
 542          *      Create new leaf node without children.
 543          */
 544
 545         ln = node_alloc();
 546
 547         if (!ln)
 548                 return ERR_PTR(-ENOMEM);
 549         ln->fn_bit = plen;
 550
 551         ln->parent = pn;
 552         ln->fn_sernum = sernum;
 553
 554         if (dir)
 555                 pn->right = ln;
 556         else
 557                 pn->left  = ln;
 558
 559         return ln;
 560
 561
 562 insert_above:
 563         /*
 564          * split since we don't have a common prefix anymore or
 565          * we have a less significant route.
 566          * we've to insert an intermediate node on the list
 567          * this new node will point to the one we need to create
 568          * and the current
 569          */
 570
 571         pn = fn->parent;
 572
 573         /* find 1st bit in difference between the 2 addrs.
 574
 575            See comment in __ipv6_addr_diff: bit may be an invalid value,
 576            but if it is >= plen, the value is ignored in any case.
 577          */
 578
 579         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 580
 581         /*
 582          *              (intermediate)[in]
 583          *                /        \
 584          *      (new leaf node)[ln] (old node)[fn]
 585          */
 586         if (plen > bit) {
 587                 in = node_alloc();
 588                 ln = node_alloc();
 589
 590                 if (!in || !ln) {
 591                         if (in)
 592                                 node_free(in);
 593                         if (ln)
 594                                 node_free(ln);
 595                         return ERR_PTR(-ENOMEM);
 596                 }
 597
 598                 /*
 599                  * new intermediate node.
 600                  * RTN_RTINFO will
 601                  * be off since that an address that chooses one of
 602                  * the branches would not match less specific routes
 603                  * in the other branch
 604                  */
 605
 606                 in->fn_bit = bit;
 607
 608                 in->parent = pn;
 609                 in->leaf = fn->leaf;
 610                 atomic_inc(&in->leaf->rt6i_ref);
 611
 612                 in->fn_sernum = sernum;
 613
 614                 /* update parent pointer */
 615                 if (dir)
 616                         pn->right = in;
 617                 else
 618                         pn->left  = in;
 619
 620                 ln->fn_bit = plen;
 621
 622                 ln->parent = in;
 623                 fn->parent = in;
 624
 625                 ln->fn_sernum = sernum;
 626
 627                 if (addr_bit_set(addr, bit)) {
 628                         in->right = ln;
 629                         in->left  = fn;
 630                 } else {
 631                         in->left  = ln;
 632                         in->right = fn;
 633                 }
 634         } else { /* plen <= bit */
 635
 636                 /*
 637                  *              (new leaf node)[ln]
 638                  *                /        \
 639                  *           (old node)[fn] NULL
 640                  */
 641
 642                 ln = node_alloc();
 643
 644                 if (!ln)
 645                         return ERR_PTR(-ENOMEM);
 646
 647                 ln->fn_bit = plen;
 648
 649                 ln->parent = pn;
 650
 651                 ln->fn_sernum = sernum;
 652
 653                 if (dir)
 654                         pn->right = ln;
 655                 else
 656                         pn->left  = ln;
 657
 658                 if (addr_bit_set(&key->addr, plen))
 659                         ln->right = fn;
 660                 else
 661                         ln->left  = fn;
 662
 663                 fn->parent = ln;
 664         }
 665         return ln;
 666 }
 667
 668 static bool rt6_qualify_for_ecmp(struct rt6_info *rt)
 669 {
 670         return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
 671                RTF_GATEWAY;
 672 }
 673
 674 static void fib6_copy_metrics(u32 *mp, const struct mx6_config *mxc)
 675 {
 676         int i;
 677
 678         for (i = 0; i < RTAX_MAX; i++) {
 679                 if (test_bit(i, mxc->mx_valid))
 680                         mp[i] = mxc->mx[i];
 681         }
 682 }
 683
 684 static int fib6_commit_metrics(struct dst_entry *dst, struct mx6_config *mxc)
 685 {
 686         if (!mxc->mx)
 687                 return 0;
 688
 689         if (dst->flags & DST_HOST) {
 690                 u32 *mp = dst_metrics_write_ptr(dst);
 691
 692                 if (unlikely(!mp))
 693                         return -ENOMEM;
 694
 695                 fib6_copy_metrics(mp, mxc);
 696         } else {
 697                 dst_init_metrics(dst, mxc->mx, false);
 698
 699                 /* We've stolen mx now. */
 700                 mxc->mx = NULL;
 701         }
 702
 703         return 0;
 704 }
 705
 706 static void fib6_purge_rt(struct rt6_info *rt, struct fib6_node *fn,
 707                           struct net *net)
 708 {
 709         if (atomic_read(&rt->rt6i_ref) != 1) {
 710                 /* This route is used as dummy address holder in some split
 711                  * nodes. It is not leaked, but it still holds other resources,
 712                  * which must be released in time. So, scan ascendant nodes
 713                  * and replace dummy references to this route with references
 714                  * to still alive ones.
 715                  */
 716                 while (fn) {
 717                         if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
 718                                 fn->leaf = fib6_find_prefix(net, fn);
 719                                 atomic_inc(&fn->leaf->rt6i_ref);
 720                                 rt6_release(rt);
 721                         }
 722                         fn = fn->parent;
 723                 }
 724                 /* No more references are possible at this point. */
 725                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
 726         }
 727 }
 728
 729 /*
 730  *      Insert routing information in a node.
 731  */
 732
 733 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 734                             struct nl_info *info, struct mx6_config *mxc)
 735 {
 736         struct rt6_info *iter = NULL;
 737         struct rt6_info **ins;
 738         struct rt6_info **fallback_ins = NULL;
 739         int replace = (info->nlh &&
 740                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 741         int add = (!info->nlh ||
 742                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
 743         int found = 0;
 744         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
 745         int err;
 746
 747         ins = &fn->leaf;
 748
 749         for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
 750                 /*
 751                  *      Search for duplicates
 752                  */
 753
 754                 if (iter->rt6i_metric == rt->rt6i_metric) {
 755                         /*
 756                          *      Same priority level
 757                          */
 758                         if (info->nlh &&
 759                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
 760                                 return -EEXIST;
 761                         if (replace) {
 762                                 if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
 763                                         found++;
 764                                         break;
 765                                 }
 766                                 if (rt_can_ecmp)
 767                                         fallback_ins = fallback_ins ?: ins;
 768                                 goto next_iter;
 769                         }
 770
 771                         if (iter->dst.dev == rt->dst.dev &&
 772                             iter->rt6i_idev == rt->rt6i_idev &&
 773                             ipv6_addr_equal(&iter->rt6i_gateway,
 774                                             &rt->rt6i_gateway)) {
 775                                 if (rt->rt6i_nsiblings)
 776                                         rt->rt6i_nsiblings = 0;
 777                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
 778                                         return -EEXIST;
 779                                 if (!(rt->rt6i_flags & RTF_EXPIRES))
 780                                         rt6_clean_expires(iter);
 781                                 else
 782                                         rt6_set_expires(iter, rt->dst.expires);
 783                                 iter->rt6i_pmtu = rt->rt6i_pmtu;
 784                                 return -EEXIST;
 785                         }
 786                         /* If we have the same destination and the same metric,
 787                          * but not the same gateway, then the route we try to
 788                          * add is sibling to this route, increment our counter
 789                          * of siblings, and later we will add our route to the
 790                          * list.
 791                          * Only static routes (which don't have flag
 792                          * RTF_EXPIRES) are used for ECMPv6.
 793                          *
 794                          * To avoid long list, we only had siblings if the
 795                          * route have a gateway.
 796                          */
 797                         if (rt_can_ecmp &&
 798                             rt6_qualify_for_ecmp(iter))
 799                                 rt->rt6i_nsiblings++;
 800                 }
 801
 802                 if (iter->rt6i_metric > rt->rt6i_metric)
 803                         break;
 804
 805 next_iter:
 806                 ins = &iter->dst.rt6_next;
 807         }
 808
 809         if (fallback_ins && !found) {
 810                 /* No ECMP-able route found, replace first non-ECMP one */
 811                 ins = fallback_ins;
 812                 iter = *ins;
 813                 found++;
 814         }
 815
 816         /* Reset round-robin state, if necessary */
 817         if (ins == &fn->leaf)
 818                 fn->rr_ptr = NULL;
 819
 820         /* Link this route to others same route. */
 821         if (rt->rt6i_nsiblings) {
 822                 unsigned int rt6i_nsiblings;
 823                 struct rt6_info *sibling, *temp_sibling;
 824
 825                 /* Find the first route that have the same metric */
 826                 sibling = fn->leaf;
 827                 while (sibling) {
 828                         if (sibling->rt6i_metric == rt->rt6i_metric &&
 829                             rt6_qualify_for_ecmp(sibling)) {
 830                                 list_add_tail(&rt->rt6i_siblings,
 831                                               &sibling->rt6i_siblings);
 832                                 break;
 833                         }
 834                         sibling = sibling->dst.rt6_next;
 835                 }
 836                 /* For each sibling in the list, increment the counter of
 837                  * siblings. BUG() if counters does not match, list of siblings
 838                  * is broken!
 839                  */
 840                 rt6i_nsiblings = 0;
 841                 list_for_each_entry_safe(sibling, temp_sibling,
 842                                          &rt->rt6i_siblings, rt6i_siblings) {
 843                         sibling->rt6i_nsiblings++;
 844                         BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
 845                         rt6i_nsiblings++;
 846                 }
 847                 BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
 848         }
 849
 850         /*
 851          *      insert node
 852          */
 853         if (!replace) {
 854                 if (!add)
 855                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
 856
 857 add:
 858                 err = fib6_commit_metrics(&rt->dst, mxc);
 859                 if (err)
 860                         return err;
 861
 862                 rt->dst.rt6_next = iter;
 863                 *ins = rt;
 864                 rt->rt6i_node = fn;
 865                 atomic_inc(&rt->rt6i_ref);
 866                 inet6_rt_notify(RTM_NEWROUTE, rt, info, 0);
 867                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 868
 869                 if (!(fn->fn_flags & RTN_RTINFO)) {
 870                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 871                         fn->fn_flags |= RTN_RTINFO;
 872                 }
 873
 874         } else {
 875                 int nsiblings;
 876
 877                 if (!found) {
 878                         if (add)
 879                                 goto add;
 880                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
 881                         return -ENOENT;
 882                 }
 883
 884                 err = fib6_commit_metrics(&rt->dst, mxc);
 885                 if (err)
 886                         return err;
 887
 888                 *ins = rt;
 889                 rt->rt6i_node = fn;
 890                 rt->dst.rt6_next = iter->dst.rt6_next;
 891                 atomic_inc(&rt->rt6i_ref);
 892                 inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
 893                 if (!(fn->fn_flags & RTN_RTINFO)) {
 894                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 895                         fn->fn_flags |= RTN_RTINFO;
 896                 }
 897                 nsiblings = iter->rt6i_nsiblings;
 898                 fib6_purge_rt(iter, fn, info->nl_net);
 899                 rt6_release(iter);
 900
 901                 if (nsiblings) {
 902                         /* Replacing an ECMP route, remove all siblings */
 903                         ins = &rt->dst.rt6_next;
 904                         iter = *ins;
 905                         while (iter) {
 906                                 if (rt6_qualify_for_ecmp(iter)) {
 907                                         *ins = iter->dst.rt6_next;
 908                                         fib6_purge_rt(iter, fn, info->nl_net);
 909                                         rt6_release(iter);
 910                                         nsiblings--;
 911                                 } else {
 912                                         ins = &iter->dst.rt6_next;
 913                                 }
 914                                 iter = *ins;
 915                         }
 916                         WARN_ON(nsiblings != 0);
 917                 }
 918         }
 919
 920         return 0;
 921 }
 922
 923 static void fib6_start_gc(struct net *net, struct rt6_info *rt)
 924 {
 925         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 926             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 927                 mod_timer(&net->ipv6.ip6_fib_timer,
 928                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 929 }
 930
 931 void fib6_force_start_gc(struct net *net)
 932 {
 933         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 934                 mod_timer(&net->ipv6.ip6_fib_timer,
 935                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 936 }
 937
 938 /*
 939  *      Add routing information to the routing tree.
 940  *      <destination addr>/<source addr>
 941  *      with source addr info in sub-trees
 942  */
 943
 944 int fib6_add(struct fib6_node *root, struct rt6_info *rt,
 945              struct nl_info *info, struct mx6_config *mxc)
 946 {
 947         struct fib6_node *fn, *pn = NULL;
 948         int err = -ENOMEM;
 949         int allow_create = 1;
 950         int replace_required = 0;
 951         int sernum = fib6_new_sernum(info->nl_net);
 952
 953         if (WARN_ON_ONCE((rt->dst.flags & DST_NOCACHE) &&
 954                          !atomic_read(&rt->dst.__refcnt)))
 955                 return -EINVAL;
 956
 957         if (info->nlh) {
 958                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 959                         allow_create = 0;
 960                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 961                         replace_required = 1;
 962         }
 963         if (!allow_create && !replace_required)
 964                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 965
 966         fn = fib6_add_1(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
 967                         offsetof(struct rt6_info, rt6i_dst), allow_create,
 968                         replace_required, sernum);
 969         if (IS_ERR(fn)) {
 970                 err = PTR_ERR(fn);
 971                 fn = NULL;
 972                 goto out;
 973         }
 974
 975         pn = fn;
 976
 977 #ifdef CONFIG_IPV6_SUBTREES
 978         if (rt->rt6i_src.plen) {
 979                 struct fib6_node *sn;
 980
 981                 if (!fn->subtree) {
 982                         struct fib6_node *sfn;
 983
 984                         /*
 985                          * Create subtree.
 986                          *
 987                          *              fn[main tree]
 988                          *              |
 989                          *              sfn[subtree root]
 990                          *                 \
 991                          *                  sn[new leaf node]
 992                          */
 993
 994                         /* Create subtree root node */
 995                         sfn = node_alloc();
 996                         if (!sfn)
 997                                 goto st_failure;
 998
 999                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
1000                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
1001                         sfn->fn_flags = RTN_ROOT;
1002                         sfn->fn_sernum = sernum;
1003
1004                         /* Now add the first leaf node to new subtree */
1005
1006                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
1007                                         rt->rt6i_src.plen,
1008                                         offsetof(struct rt6_info, rt6i_src),
1009                                         allow_create, replace_required, sernum);
1010
1011                         if (IS_ERR(sn)) {
1012                                 /* If it is failed, discard just allocated
1013                                    root, and then (in st_failure) stale node
1014                                    in main tree.
1015                                  */
1016                                 node_free(sfn);
1017                                 err = PTR_ERR(sn);
1018                                 goto st_failure;
1019                         }
1020
1021                         /* Now link new subtree to main tree */
1022                         sfn->parent = fn;
1023                         fn->subtree = sfn;
1024                 } else {
1025                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
1026                                         rt->rt6i_src.plen,
1027                                         offsetof(struct rt6_info, rt6i_src),
1028                                         allow_create, replace_required, sernum);
1029
1030                         if (IS_ERR(sn)) {
1031                                 err = PTR_ERR(sn);
1032                                 goto st_failure;
1033                         }
1034                 }
1035
1036                 if (!fn->leaf) {
1037                         fn->leaf = rt;
1038                         atomic_inc(&rt->rt6i_ref);
1039                 }
1040                 fn = sn;
1041         }
1042 #endif
1043
1044         err = fib6_add_rt2node(fn, rt, info, mxc);
1045         if (!err) {
1046                 fib6_start_gc(info->nl_net, rt);
1047                 if (!(rt->rt6i_flags & RTF_CACHE))
1048                         fib6_prune_clones(info->nl_net, pn);
1049                 rt->dst.flags &= ~DST_NOCACHE;
1050         }
1051
1052 out:
1053         if (err) {
1054 #ifdef CONFIG_IPV6_SUBTREES
1055                 /*
1056                  * If fib6_add_1 has cleared the old leaf pointer in the
1057                  * super-tree leaf node we have to find a new one for it.
1058                  */
1059                 if (pn != fn && pn->leaf == rt) {
1060                         pn->leaf = NULL;
1061                         atomic_dec(&rt->rt6i_ref);
1062                 }
1063                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
1064                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
1065 #if RT6_DEBUG >= 2
1066                         if (!pn->leaf) {
1067                                 WARN_ON(pn->leaf == NULL);
1068                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
1069                         }
1070 #endif
1071                         atomic_inc(&pn->leaf->rt6i_ref);
1072                 }
1073 #endif
1074                 if (!(rt->dst.flags & DST_NOCACHE))
1075                         dst_free(&rt->dst);
1076         }
1077         return err;
1078
1079 #ifdef CONFIG_IPV6_SUBTREES
1080         /* Subtree creation failed, probably main tree node
1081            is orphan. If it is, shoot it.
1082          */
1083 st_failure:
1084         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
1085                 fib6_repair_tree(info->nl_net, fn);
1086         if (!(rt->dst.flags & DST_NOCACHE))
1087                 dst_free(&rt->dst);
1088         return err;
1089 #endif
1090 }
1091
1092 /*
1093  *      Routing tree lookup
1094  *
1095  */
1096
1097 struct lookup_args {
1098         int                     offset;         /* key offset on rt6_info       */
1099         const struct in6_addr   *addr;          /* search key                   */
1100 };
1101
1102 static struct fib6_node *fib6_lookup_1(struct fib6_node *root,
1103                                        struct lookup_args *args)
1104 {
1105         struct fib6_node *fn;
1106         __be32 dir;
1107
1108         if (unlikely(args->offset == 0))
1109                 return NULL;
1110
1111         /*
1112          *      Descend on a tree
1113          */
1114
1115         fn = root;
1116
1117         for (;;) {
1118                 struct fib6_node *next;
1119
1120                 dir = addr_bit_set(args->addr, fn->fn_bit);
1121
1122                 next = dir ? fn->right : fn->left;
1123
1124                 if (next) {
1125                         fn = next;
1126                         continue;
1127                 }
1128                 break;
1129         }
1130
1131         while (fn) {
1132                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
1133                         struct rt6key *key;
1134
1135                         key = (struct rt6key *) ((u8 *) fn->leaf +
1136                                                  args->offset);
1137
1138                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1139 #ifdef CONFIG_IPV6_SUBTREES
1140                                 if (fn->subtree) {
1141                                         struct fib6_node *sfn;
1142                                         sfn = fib6_lookup_1(fn->subtree,
1143                                                             args + 1);
1144                                         if (!sfn)
1145                                                 goto backtrack;
1146                                         fn = sfn;
1147                                 }
1148 #endif
1149                                 if (fn->fn_flags & RTN_RTINFO)
1150                                         return fn;
1151                         }
1152                 }
1153 #ifdef CONFIG_IPV6_SUBTREES
1154 backtrack:
1155 #endif
1156                 if (fn->fn_flags & RTN_ROOT)
1157                         break;
1158
1159                 fn = fn->parent;
1160         }
1161
1162         return NULL;
1163 }
1164
1165 struct fib6_node *fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
1166                               const struct in6_addr *saddr)
1167 {
1168         struct fib6_node *fn;
1169         struct lookup_args args[] = {
1170                 {
1171                         .offset = offsetof(struct rt6_info, rt6i_dst),
1172                         .addr = daddr,
1173                 },
1174 #ifdef CONFIG_IPV6_SUBTREES
1175                 {
1176                         .offset = offsetof(struct rt6_info, rt6i_src),
1177                         .addr = saddr,
1178                 },
1179 #endif
1180                 {
1181                         .offset = 0,    /* sentinel */
1182                 }
1183         };
1184
1185         fn = fib6_lookup_1(root, daddr ? args : args + 1);
1186         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1187                 fn = root;
1188
1189         return fn;
1190 }
1191
1192 /*
1193  *      Get node with specified destination prefix (and source prefix,
1194  *      if subtrees are used)
1195  */
1196
1197
1198 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1199                                        const struct in6_addr *addr,
1200                                        int plen, int offset)
1201 {
1202         struct fib6_node *fn;
1203
1204         for (fn = root; fn ; ) {
1205                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1206
1207                 /*
1208                  *      Prefix match
1209                  */
1210                 if (plen < fn->fn_bit ||
1211                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1212                         return NULL;
1213
1214                 if (plen == fn->fn_bit)
1215                         return fn;
1216
1217                 /*
1218                  *      We have more bits to go
1219                  */
1220                 if (addr_bit_set(addr, fn->fn_bit))
1221                         fn = fn->right;
1222                 else
1223                         fn = fn->left;
1224         }
1225         return NULL;
1226 }
1227
1228 struct fib6_node *fib6_locate(struct fib6_node *root,
1229                               const struct in6_addr *daddr, int dst_len,
1230                               const struct in6_addr *saddr, int src_len)
1231 {
1232         struct fib6_node *fn;
1233
1234         fn = fib6_locate_1(root, daddr, dst_len,
1235                            offsetof(struct rt6_info, rt6i_dst));
1236
1237 #ifdef CONFIG_IPV6_SUBTREES
1238         if (src_len) {
1239                 WARN_ON(saddr == NULL);
1240                 if (fn && fn->subtree)
1241                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
1242                                            offsetof(struct rt6_info, rt6i_src));
1243         }
1244 #endif
1245
1246         if (fn && fn->fn_flags & RTN_RTINFO)
1247                 return fn;
1248
1249         return NULL;
1250 }
1251
1252
1253 /*
1254  *      Deletion
1255  *
1256  */
1257
1258 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1259 {
1260         if (fn->fn_flags & RTN_ROOT)
1261                 return net->ipv6.ip6_null_entry;
1262
1263         while (fn) {
1264                 if (fn->left)
1265                         return fn->left->leaf;
1266                 if (fn->right)
1267                         return fn->right->leaf;
1268
1269                 fn = FIB6_SUBTREE(fn);
1270         }
1271         return NULL;
1272 }
1273
1274 /*
1275  *      Called to trim the tree of intermediate nodes when possible. "fn"
1276  *      is the node we want to try and remove.
1277  */
1278
1279 static struct fib6_node *fib6_repair_tree(struct net *net,
1280                                            struct fib6_node *fn)
1281 {
1282         int children;
1283         int nstate;
1284         struct fib6_node *child, *pn;
1285         struct fib6_walker *w;
1286         int iter = 0;
1287
1288         for (;;) {
1289                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1290                 iter++;
1291
1292                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1293                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1294                 WARN_ON(fn->leaf);
1295
1296                 children = 0;
1297                 child = NULL;
1298                 if (fn->right)
1299                         child = fn->right, children |= 1;
1300                 if (fn->left)
1301                         child = fn->left, children |= 2;
1302
1303                 if (children == 3 || FIB6_SUBTREE(fn)
1304 #ifdef CONFIG_IPV6_SUBTREES
1305                     /* Subtree root (i.e. fn) may have one child */
1306                     || (children && fn->fn_flags & RTN_ROOT)
1307 #endif
1308                     ) {
1309                         fn->leaf = fib6_find_prefix(net, fn);
1310 #if RT6_DEBUG >= 2
1311                         if (!fn->leaf) {
1312                                 WARN_ON(!fn->leaf);
1313                                 fn->leaf = net->ipv6.ip6_null_entry;
1314                         }
1315 #endif
1316                         atomic_inc(&fn->leaf->rt6i_ref);
1317                         return fn->parent;
1318                 }
1319
1320                 pn = fn->parent;
1321 #ifdef CONFIG_IPV6_SUBTREES
1322                 if (FIB6_SUBTREE(pn) == fn) {
1323                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1324                         FIB6_SUBTREE(pn) = NULL;
1325                         nstate = FWS_L;
1326                 } else {
1327                         WARN_ON(fn->fn_flags & RTN_ROOT);
1328 #endif
1329                         if (pn->right == fn)
1330                                 pn->right = child;
1331                         else if (pn->left == fn)
1332                                 pn->left = child;
1333 #if RT6_DEBUG >= 2
1334                         else
1335                                 WARN_ON(1);
1336 #endif
1337                         if (child)
1338                                 child->parent = pn;
1339                         nstate = FWS_R;
1340 #ifdef CONFIG_IPV6_SUBTREES
1341                 }
1342 #endif
1343
1344                 read_lock(&net->ipv6.fib6_walker_lock);
1345                 FOR_WALKERS(net, w) {
1346                         if (!child) {
1347                                 if (w->root == fn) {
1348                                         w->root = w->node = NULL;
1349                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1350                                 } else if (w->node == fn) {
1351                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1352                                         w->node = pn;
1353                                         w->state = nstate;
1354                                 }
1355                         } else {
1356                                 if (w->root == fn) {
1357                                         w->root = child;
1358                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1359                                 }
1360                                 if (w->node == fn) {
1361                                         w->node = child;
1362                                         if (children&2) {
1363                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1364                                                 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1365                                         } else {
1366                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1367                                                 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1368                                         }
1369                                 }
1370                         }
1371                 }
1372                 read_unlock(&net->ipv6.fib6_walker_lock);
1373
1374                 node_free(fn);
1375                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1376                         return pn;
1377
1378                 rt6_release(pn->leaf);
1379                 pn->leaf = NULL;
1380                 fn = pn;
1381         }
1382 }
1383
1384 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1385                            struct nl_info *info)
1386 {
1387         struct fib6_walker *w;
1388         struct rt6_info *rt = *rtp;
1389         struct net *net = info->nl_net;
1390
1391         RT6_TRACE("fib6_del_route\n");
1392
1393         /* Unlink it */
1394         *rtp = rt->dst.rt6_next;
1395         rt->rt6i_node = NULL;
1396         net->ipv6.rt6_stats->fib_rt_entries--;
1397         net->ipv6.rt6_stats->fib_discarded_routes++;
1398
1399         /* Reset round-robin state, if necessary */
1400         if (fn->rr_ptr == rt)
1401                 fn->rr_ptr = NULL;
1402
1403         /* Remove this entry from other siblings */
1404         if (rt->rt6i_nsiblings) {
1405                 struct rt6_info *sibling, *next_sibling;
1406
1407                 list_for_each_entry_safe(sibling, next_sibling,
1408                                          &rt->rt6i_siblings, rt6i_siblings)
1409                         sibling->rt6i_nsiblings--;
1410                 rt->rt6i_nsiblings = 0;
1411                 list_del_init(&rt->rt6i_siblings);
1412         }
1413
1414         /* Adjust walkers */
1415         read_lock(&net->ipv6.fib6_walker_lock);
1416         FOR_WALKERS(net, w) {
1417                 if (w->state == FWS_C && w->leaf == rt) {
1418                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1419                         w->leaf = rt->dst.rt6_next;
1420                         if (!w->leaf)
1421                                 w->state = FWS_U;
1422                 }
1423         }
1424         read_unlock(&net->ipv6.fib6_walker_lock);
1425
1426         rt->dst.rt6_next = NULL;
1427
1428         /* If it was last route, expunge its radix tree node */
1429         if (!fn->leaf) {
1430                 fn->fn_flags &= ~RTN_RTINFO;
1431                 net->ipv6.rt6_stats->fib_route_nodes--;
1432                 fn = fib6_repair_tree(net, fn);
1433         }
1434
1435         fib6_purge_rt(rt, fn, net);
1436
1437         inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
1438         rt6_release(rt);
1439 }
1440
1441 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1442 {
1443         struct net *net = info->nl_net;
1444         struct fib6_node *fn = rt->rt6i_node;
1445         struct rt6_info **rtp;
1446
1447 #if RT6_DEBUG >= 2
1448         if (rt->dst.obsolete > 0) {
1449                 WARN_ON(fn);
1450                 return -ENOENT;
1451         }
1452 #endif
1453         if (!fn || rt == net->ipv6.ip6_null_entry)
1454                 return -ENOENT;
1455
1456         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1457
1458         if (!(rt->rt6i_flags & RTF_CACHE)) {
1459                 struct fib6_node *pn = fn;
1460 #ifdef CONFIG_IPV6_SUBTREES
1461                 /* clones of this route might be in another subtree */
1462                 if (rt->rt6i_src.plen) {
1463                         while (!(pn->fn_flags & RTN_ROOT))
1464                                 pn = pn->parent;
1465                         pn = pn->parent;
1466                 }
1467 #endif
1468                 fib6_prune_clones(info->nl_net, pn);
1469         }
1470
1471         /*
1472          *      Walk the leaf entries looking for ourself
1473          */
1474
1475         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1476                 if (*rtp == rt) {
1477                         fib6_del_route(fn, rtp, info);
1478                         return 0;
1479                 }
1480         }
1481         return -ENOENT;
1482 }
1483
1484 /*
1485  *      Tree traversal function.
1486  *
1487  *      Certainly, it is not interrupt safe.
1488  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1489  *      It means, that we can modify tree during walking
1490  *      and use this function for garbage collection, clone pruning,
1491  *      cleaning tree when a device goes down etc. etc.
1492  *
1493  *      It guarantees that every node will be traversed,
1494  *      and that it will be traversed only once.
1495  *
1496  *      Callback function w->func may return:
1497  *      0 -> continue walking.
1498  *      positive value -> walking is suspended (used by tree dumps,
1499  *      and probably by gc, if it will be split to several slices)
1500  *      negative value -> terminate walking.
1501  *
1502  *      The function itself returns:
1503  *      0   -> walk is complete.
1504  *      >0  -> walk is incomplete (i.e. suspended)
1505  *      <0  -> walk is terminated by an error.
1506  */
1507
1508 static int fib6_walk_continue(struct fib6_walker *w)
1509 {
1510         struct fib6_node *fn, *pn;
1511
1512         for (;;) {
1513                 fn = w->node;
1514                 if (!fn)
1515                         return 0;
1516
1517                 if (w->prune && fn != w->root &&
1518                     fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1519                         w->state = FWS_C;
1520                         w->leaf = fn->leaf;
1521                 }
1522                 switch (w->state) {
1523 #ifdef CONFIG_IPV6_SUBTREES
1524                 case FWS_S:
1525                         if (FIB6_SUBTREE(fn)) {
1526                                 w->node = FIB6_SUBTREE(fn);
1527                                 continue;
1528                         }
1529                         w->state = FWS_L;
1530 #endif
1531                 case FWS_L:
1532                         if (fn->left) {
1533                                 w->node = fn->left;
1534                                 w->state = FWS_INIT;
1535                                 continue;
1536                         }
1537                         w->state = FWS_R;
1538                 case FWS_R:
1539                         if (fn->right) {
1540                                 w->node = fn->right;
1541                                 w->state = FWS_INIT;
1542                                 continue;
1543                         }
1544                         w->state = FWS_C;
1545                         w->leaf = fn->leaf;
1546                 case FWS_C:
1547                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1548                                 int err;
1549
1550                                 if (w->skip) {
1551                                         w->skip--;
1552                                         goto skip;
1553                                 }
1554
1555                                 err = w->func(w);
1556                                 if (err)
1557                                         return err;
1558
1559                                 w->count++;
1560                                 continue;
1561                         }
1562 skip:
1563                         w->state = FWS_U;
1564                 case FWS_U:
1565                         if (fn == w->root)
1566                                 return 0;
1567                         pn = fn->parent;
1568                         w->node = pn;
1569 #ifdef CONFIG_IPV6_SUBTREES
1570                         if (FIB6_SUBTREE(pn) == fn) {
1571                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1572                                 w->state = FWS_L;
1573                                 continue;
1574                         }
1575 #endif
1576                         if (pn->left == fn) {
1577                                 w->state = FWS_R;
1578                                 continue;
1579                         }
1580                         if (pn->right == fn) {
1581                                 w->state = FWS_C;
1582                                 w->leaf = w->node->leaf;
1583                                 continue;
1584                         }
1585 #if RT6_DEBUG >= 2
1586                         WARN_ON(1);
1587 #endif
1588                 }
1589         }
1590 }
1591
1592 static int fib6_walk(struct net *net, struct fib6_walker *w)
1593 {
1594         int res;
1595
1596         w->state = FWS_INIT;
1597         w->node = w->root;
1598
1599         fib6_walker_link(net, w);
1600         res = fib6_walk_continue(w);
1601         if (res <= 0)
1602                 fib6_walker_unlink(net, w);
1603         return res;
1604 }
1605
1606 static int fib6_clean_node(struct fib6_walker *w)
1607 {
1608         int res;
1609         struct rt6_info *rt;
1610         struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
1611         struct nl_info info = {
1612                 .nl_net = c->net,
1613         };
1614
1615         if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
1616             w->node->fn_sernum != c->sernum)
1617                 w->node->fn_sernum = c->sernum;
1618
1619         if (!c->func) {
1620                 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
1621                 w->leaf = NULL;
1622                 return 0;
1623         }
1624
1625         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1626                 res = c->func(rt, c->arg);
1627                 if (res < 0) {
1628                         w->leaf = rt;
1629                         res = fib6_del(rt, &info);
1630                         if (res) {
1631 #if RT6_DEBUG >= 2
1632                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1633                                          __func__, rt, rt->rt6i_node, res);
1634 #endif
1635                                 continue;
1636                         }
1637                         return 0;
1638                 }
1639                 WARN_ON(res != 0);
1640         }
1641         w->leaf = rt;
1642         return 0;
1643 }
1644
1645 /*
1646  *      Convenient frontend to tree walker.
1647  *
1648  *      func is called on each route.
1649  *              It may return -1 -> delete this route.
1650  *                            0  -> continue walking
1651  *
1652  *      prune==1 -> only immediate children of node (certainly,
1653  *      ignoring pure split nodes) will be scanned.
1654  */
1655
1656 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1657                             int (*func)(struct rt6_info *, void *arg),
1658                             bool prune, int sernum, void *arg)
1659 {
1660         struct fib6_cleaner c;
1661
1662         c.w.root = root;
1663         c.w.func = fib6_clean_node;
1664         c.w.prune = prune;
1665         c.w.count = 0;
1666         c.w.skip = 0;
1667         c.func = func;
1668         c.sernum = sernum;
1669         c.arg = arg;
1670         c.net = net;
1671
1672         fib6_walk(net, &c.w);
1673 }
1674
1675 static void __fib6_clean_all(struct net *net,
1676                              int (*func)(struct rt6_info *, void *),
1677                              int sernum, void *arg)
1678 {
1679         struct fib6_table *table;
1680         struct hlist_head *head;
1681         unsigned int h;
1682
1683         rcu_read_lock();
1684         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1685                 head = &net->ipv6.fib_table_hash[h];
1686                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1687                         write_lock_bh(&table->tb6_lock);
1688                         fib6_clean_tree(net, &table->tb6_root,
1689                                         func, false, sernum, arg);
1690                         write_unlock_bh(&table->tb6_lock);
1691                 }
1692         }
1693         rcu_read_unlock();
1694 }
1695
1696 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *),
1697                     void *arg)
1698 {
1699         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
1700 }
1701
1702 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1703 {
1704         if (rt->rt6i_flags & RTF_CACHE) {
1705                 RT6_TRACE("pruning clone %p\n", rt);
1706                 return -1;
1707         }
1708
1709         return 0;
1710 }
1711
1712 static void fib6_prune_clones(struct net *net, struct fib6_node *fn)
1713 {
1714         fib6_clean_tree(net, fn, fib6_prune_clone, true,
1715                         FIB6_NO_SERNUM_CHANGE, NULL);
1716 }
1717
1718 static void fib6_flush_trees(struct net *net)
1719 {
1720         int new_sernum = fib6_new_sernum(net);
1721
1722         __fib6_clean_all(net, NULL, new_sernum, NULL);
1723 }
1724
1725 /*
1726  *      Garbage collection
1727  */
1728
1729 struct fib6_gc_args
1730 {
1731         int                     timeout;
1732         int                     more;
1733 };
1734
1735 static int fib6_age(struct rt6_info *rt, void *arg)
1736 {
1737         struct fib6_gc_args *gc_args = arg;
1738         unsigned long now = jiffies;
1739
1740         /*
1741          *      check addrconf expiration here.
1742          *      Routes are expired even if they are in use.
1743          *
1744          *      Also age clones. Note, that clones are aged out
1745          *      only if they are not in use now.
1746          */
1747
1748         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1749                 if (time_after(now, rt->dst.expires)) {
1750                         RT6_TRACE("expiring %p\n", rt);
1751                         return -1;
1752                 }
1753                 gc_args->more++;
1754         } else if (rt->rt6i_flags & RTF_CACHE) {
1755                 if (atomic_read(&rt->dst.__refcnt) == 0 &&
1756                     time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
1757                         RT6_TRACE("aging clone %p\n", rt);
1758                         return -1;
1759                 } else if (rt->rt6i_flags & RTF_GATEWAY) {
1760                         struct neighbour *neigh;
1761                         __u8 neigh_flags = 0;
1762
1763                         neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1764                         if (neigh) {
1765                                 neigh_flags = neigh->flags;
1766                                 neigh_release(neigh);
1767                         }
1768                         if (!(neigh_flags & NTF_ROUTER)) {
1769                                 RT6_TRACE("purging route %p via non-router but gateway\n",
1770                                           rt);
1771                                 return -1;
1772                         }
1773                 }
1774                 gc_args->more++;
1775         }
1776
1777         return 0;
1778 }
1779
1780 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
1781 {
1782         struct fib6_gc_args gc_args;
1783         unsigned long now;
1784
1785         if (force) {
1786                 spin_lock_bh(&net->ipv6.fib6_gc_lock);
1787         } else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
1788                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1789                 return;
1790         }
1791         gc_args.timeout = expires ? (int)expires :
1792                           net->ipv6.sysctl.ip6_rt_gc_interval;
1793
1794         gc_args.more = icmp6_dst_gc();
1795
1796         fib6_clean_all(net, fib6_age, &gc_args);
1797         now = jiffies;
1798         net->ipv6.ip6_rt_last_gc = now;
1799
1800         if (gc_args.more)
1801                 mod_timer(&net->ipv6.ip6_fib_timer,
1802                           round_jiffies(now
1803                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1804         else
1805                 del_timer(&net->ipv6.ip6_fib_timer);
1806         spin_unlock_bh(&net->ipv6.fib6_gc_lock);
1807 }
1808
1809 static void fib6_gc_timer_cb(unsigned long arg)
1810 {
1811         fib6_run_gc(0, (struct net *)arg, true);
1812 }
1813
1814 static int __net_init fib6_net_init(struct net *net)
1815 {
1816         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1817
1818         spin_lock_init(&net->ipv6.fib6_gc_lock);
1819         rwlock_init(&net->ipv6.fib6_walker_lock);
1820         INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
1821         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1822
1823         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1824         if (!net->ipv6.rt6_stats)
1825                 goto out_timer;
1826
1827         /* Avoid false sharing : Use at least a full cache line */
1828         size = max_t(size_t, size, L1_CACHE_BYTES);
1829
1830         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1831         if (!net->ipv6.fib_table_hash)
1832                 goto out_rt6_stats;
1833
1834         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1835                                           GFP_KERNEL);
1836         if (!net->ipv6.fib6_main_tbl)
1837                 goto out_fib_table_hash;
1838
1839         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1840         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1841         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1842                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1843         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1844
1845 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1846         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1847                                            GFP_KERNEL);
1848         if (!net->ipv6.fib6_local_tbl)
1849                 goto out_fib6_main_tbl;
1850         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1851         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1852         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1853                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1854         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1855 #endif
1856         fib6_tables_init(net);
1857
1858         return 0;
1859
1860 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1861 out_fib6_main_tbl:
1862         kfree(net->ipv6.fib6_main_tbl);
1863 #endif
1864 out_fib_table_hash:
1865         kfree(net->ipv6.fib_table_hash);
1866 out_rt6_stats:
1867         kfree(net->ipv6.rt6_stats);
1868 out_timer:
1869         return -ENOMEM;
1870 }
1871
1872 static void fib6_net_exit(struct net *net)
1873 {
1874         rt6_ifdown(net, NULL);
1875         del_timer_sync(&net->ipv6.ip6_fib_timer);
1876
1877 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1878         inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1879         kfree(net->ipv6.fib6_local_tbl);
1880 #endif
1881         inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1882         kfree(net->ipv6.fib6_main_tbl);
1883         kfree(net->ipv6.fib_table_hash);
1884         kfree(net->ipv6.rt6_stats);
1885 }
1886
1887 static struct pernet_operations fib6_net_ops = {
1888         .init = fib6_net_init,
1889         .exit = fib6_net_exit,
1890 };
1891
1892 int __init fib6_init(void)
1893 {
1894         int ret = -ENOMEM;
1895
1896         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1897                                            sizeof(struct fib6_node),
1898                                            0, SLAB_HWCACHE_ALIGN,
1899                                            NULL);
1900         if (!fib6_node_kmem)
1901                 goto out;
1902
1903         ret = register_pernet_subsys(&fib6_net_ops);
1904         if (ret)
1905                 goto out_kmem_cache_create;
1906
1907         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1908                               NULL);
1909         if (ret)
1910                 goto out_unregister_subsys;
1911
1912         __fib6_flush_trees = fib6_flush_trees;
1913 out:
1914         return ret;
1915
1916 out_unregister_subsys:
1917         unregister_pernet_subsys(&fib6_net_ops);
1918 out_kmem_cache_create:
1919         kmem_cache_destroy(fib6_node_kmem);
1920         goto out;
1921 }
1922
1923 void fib6_gc_cleanup(void)
1924 {
1925         unregister_pernet_subsys(&fib6_net_ops);
1926         kmem_cache_destroy(fib6_node_kmem);
1927 }
1928
1929 #ifdef CONFIG_PROC_FS
1930
1931 struct ipv6_route_iter {
1932         struct seq_net_private p;
1933         struct fib6_walker w;
1934         loff_t skip;
1935         struct fib6_table *tbl;
1936         int sernum;
1937 };
1938
1939 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
1940 {
1941         struct rt6_info *rt = v;
1942         struct ipv6_route_iter *iter = seq->private;
1943
1944         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
1945
1946 #ifdef CONFIG_IPV6_SUBTREES
1947         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
1948 #else
1949         seq_puts(seq, "00000000000000000000000000000000 00 ");
1950 #endif
1951         if (rt->rt6i_flags & RTF_GATEWAY)
1952                 seq_printf(seq, "%pi6", &rt->rt6i_gateway);
1953         else
1954                 seq_puts(seq, "00000000000000000000000000000000");
1955
1956         seq_printf(seq, " %08x %08x %08x %08x %8s\n",
1957                    rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
1958                    rt->dst.__use, rt->rt6i_flags,
1959                    rt->dst.dev ? rt->dst.dev->name : "");
1960         iter->w.leaf = NULL;
1961         return 0;
1962 }
1963
1964 static int ipv6_route_yield(struct fib6_walker *w)
1965 {
1966         struct ipv6_route_iter *iter = w->args;
1967
1968         if (!iter->skip)
1969                 return 1;
1970
1971         do {
1972                 iter->w.leaf = iter->w.leaf->dst.rt6_next;
1973                 iter->skip--;
1974                 if (!iter->skip && iter->w.leaf)
1975                         return 1;
1976         } while (iter->w.leaf);
1977
1978         return 0;
1979 }
1980
1981 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
1982                                       struct net *net)
1983 {
1984         memset(&iter->w, 0, sizeof(iter->w));
1985         iter->w.func = ipv6_route_yield;
1986         iter->w.root = &iter->tbl->tb6_root;
1987         iter->w.state = FWS_INIT;
1988         iter->w.node = iter->w.root;
1989         iter->w.args = iter;
1990         iter->sernum = iter->w.root->fn_sernum;
1991         INIT_LIST_HEAD(&iter->w.lh);
1992         fib6_walker_link(net, &iter->w);
1993 }
1994
1995 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
1996                                                     struct net *net)
1997 {
1998         unsigned int h;
1999         struct hlist_node *node;
2000
2001         if (tbl) {
2002                 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
2003                 node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
2004         } else {
2005                 h = 0;
2006                 node = NULL;
2007         }
2008
2009         while (!node && h < FIB6_TABLE_HASHSZ) {
2010                 node = rcu_dereference_bh(
2011                         hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
2012         }
2013         return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
2014 }
2015
2016 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
2017 {
2018         if (iter->sernum != iter->w.root->fn_sernum) {
2019                 iter->sernum = iter->w.root->fn_sernum;
2020                 iter->w.state = FWS_INIT;
2021                 iter->w.node = iter->w.root;
2022                 WARN_ON(iter->w.skip);
2023                 iter->w.skip = iter->w.count;
2024         }
2025 }
2026
2027 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2028 {
2029         int r;
2030         struct rt6_info *n;
2031         struct net *net = seq_file_net(seq);
2032         struct ipv6_route_iter *iter = seq->private;
2033
2034         if (!v)
2035                 goto iter_table;
2036
2037         n = ((struct rt6_info *)v)->dst.rt6_next;
2038         if (n) {
2039                 ++*pos;
2040                 return n;
2041         }
2042
2043 iter_table:
2044         ipv6_route_check_sernum(iter);
2045         read_lock(&iter->tbl->tb6_lock);
2046         r = fib6_walk_continue(&iter->w);
2047         read_unlock(&iter->tbl->tb6_lock);
2048         if (r > 0) {
2049                 if (v)
2050                         ++*pos;
2051                 return iter->w.leaf;
2052         } else if (r < 0) {
2053                 fib6_walker_unlink(net, &iter->w);
2054                 return NULL;
2055         }
2056         fib6_walker_unlink(net, &iter->w);
2057
2058         iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
2059         if (!iter->tbl)
2060                 return NULL;
2061
2062         ipv6_route_seq_setup_walk(iter, net);
2063         goto iter_table;
2064 }
2065
2066 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
2067         __acquires(RCU_BH)
2068 {
2069         struct net *net = seq_file_net(seq);
2070         struct ipv6_route_iter *iter = seq->private;
2071
2072         rcu_read_lock_bh();
2073         iter->tbl = ipv6_route_seq_next_table(NULL, net);
2074         iter->skip = *pos;
2075
2076         if (iter->tbl) {
2077                 ipv6_route_seq_setup_walk(iter, net);
2078                 return ipv6_route_seq_next(seq, NULL, pos);
2079         } else {
2080                 return NULL;
2081         }
2082 }
2083
2084 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
2085 {
2086         struct fib6_walker *w = &iter->w;
2087         return w->node && !(w->state == FWS_U && w->node == w->root);
2088 }
2089
2090 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2091         __releases(RCU_BH)
2092 {
2093         struct net *net = seq_file_net(seq);
2094         struct ipv6_route_iter *iter = seq->private;
2095
2096         if (ipv6_route_iter_active(iter))
2097                 fib6_walker_unlink(net, &iter->w);
2098
2099         rcu_read_unlock_bh();
2100 }
2101
2102 static const struct seq_operations ipv6_route_seq_ops = {
2103         .start  = ipv6_route_seq_start,
2104         .next   = ipv6_route_seq_next,
2105         .stop   = ipv6_route_seq_stop,
2106         .show   = ipv6_route_seq_show
2107 };
2108
2109 int ipv6_route_open(struct inode *inode, struct file *file)
2110 {
2111         return seq_open_net(inode, file, &ipv6_route_seq_ops,
2112                             sizeof(struct ipv6_route_iter));
2113 }
2114
2115 #endif /* CONFIG_PROC_FS */