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