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