net/ipv6/ip6_fib.c

   1 /*
   2  *      Linux INET6 implementation
   3  *      Forwarding Information Database
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <[email protected]>
   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         free_percpu(non_pcpu_rt->rt6i_pcpu);
 181         non_pcpu_rt->rt6i_pcpu = NULL;
 182 }
 183
 184 static void rt6_release(struct rt6_info *rt)
 185 {
 186         if (atomic_dec_and_test(&rt->rt6i_ref)) {
 187                 rt6_free_pcpu(rt);
 188                 rt6_rcu_free(rt);
 189         }
 190 }
 191
 192 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 193 {
 194         unsigned int h;
 195
 196         /*
 197          * Initialize table lock at a single place to give lockdep a key,
 198          * tables aren't visible prior to being linked to the list.
 199          */
 200         rwlock_init(&tb->tb6_lock);
 201
 202         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 203
 204         /*
 205          * No protection necessary, this is the only list mutatation
 206          * operation, tables never disappear once they exist.
 207          */
 208         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 209 }
 210
 211 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 212
 213 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 214 {
 215         struct fib6_table *table;
 216
 217         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 218         if (table) {
 219                 table->tb6_id = id;
 220                 table->tb6_root.leaf = net->ipv6.ip6_null_entry;
 221                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 222                 inet_peer_base_init(&table->tb6_peers);
 223         }
 224
 225         return table;
 226 }
 227
 228 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 229 {
 230         struct fib6_table *tb;
 231
 232         if (id == 0)
 233                 id = RT6_TABLE_MAIN;
 234         tb = fib6_get_table(net, id);
 235         if (tb)
 236                 return tb;
 237
 238         tb = fib6_alloc_table(net, id);
 239         if (tb)
 240                 fib6_link_table(net, tb);
 241
 242         return tb;
 243 }
 244 EXPORT_SYMBOL_GPL(fib6_new_table);
 245
 246 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 247 {
 248         struct fib6_table *tb;
 249         struct hlist_head *head;
 250         unsigned int h;
 251
 252         if (id == 0)
 253                 id = RT6_TABLE_MAIN;
 254         h = id & (FIB6_TABLE_HASHSZ - 1);
 255         rcu_read_lock();
 256         head = &net->ipv6.fib_table_hash[h];
 257         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 258                 if (tb->tb6_id == id) {
 259                         rcu_read_unlock();
 260                         return tb;
 261                 }
 262         }
 263         rcu_read_unlock();
 264
 265         return NULL;
 266 }
 267 EXPORT_SYMBOL_GPL(fib6_get_table);
 268
 269 static void __net_init fib6_tables_init(struct net *net)
 270 {
 271         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 272         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 273 }
 274 #else
 275
 276 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 277 {
 278         return fib6_get_table(net, id);
 279 }
 280
 281 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 282 {
 283           return net->ipv6.fib6_main_tbl;
 284 }
 285
 286 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 287                                    int flags, pol_lookup_t lookup)
 288 {
 289         struct rt6_info *rt;
 290
 291         rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
 292         if (rt->rt6i_flags & RTF_REJECT &&
 293             rt->dst.error == -EAGAIN) {
 294                 ip6_rt_put(rt);
 295                 rt = net->ipv6.ip6_null_entry;
 296                 dst_hold(&rt->dst);
 297         }
 298
 299         return &rt->dst;
 300 }
 301
 302 static void __net_init fib6_tables_init(struct net *net)
 303 {
 304         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 305 }
 306
 307 #endif
 308
 309 static int fib6_dump_node(struct fib6_walker *w)
 310 {
 311         int res;
 312         struct rt6_info *rt;
 313
 314         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
 315                 res = rt6_dump_route(rt, w->args);
 316                 if (res < 0) {
 317                         /* Frame is full, suspend walking */
 318                         w->leaf = rt;
 319                         return 1;
 320                 }
 321
 322                 /* Multipath routes are dumped in one route with the
 323                  * RTA_MULTIPATH attribute. Jump 'rt' to point to the
 324                  * last sibling of this route (no need to dump the
 325                  * sibling routes again)
 326                  */
 327                 if (rt->rt6i_nsiblings)
 328                         rt = list_last_entry(&rt->rt6i_siblings,
 329                                              struct rt6_info,
 330                                              rt6i_siblings);
 331         }
 332         w->leaf = NULL;
 333         return 0;
 334 }
 335
 336 static void fib6_dump_end(struct netlink_callback *cb)
 337 {
 338         struct net *net = sock_net(cb->skb->sk);
 339         struct fib6_walker *w = (void *)cb->args[2];
 340
 341         if (w) {
 342                 if (cb->args[4]) {
 343                         cb->args[4] = 0;
 344                         fib6_walker_unlink(net, w);
 345                 }
 346                 cb->args[2] = 0;
 347                 kfree(w);
 348         }
 349         cb->done = (void *)cb->args[3];
 350         cb->args[1] = 3;
 351 }
 352
 353 static int fib6_dump_done(struct netlink_callback *cb)
 354 {
 355         fib6_dump_end(cb);
 356         return cb->done ? cb->done(cb) : 0;
 357 }
 358
 359 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 360                            struct netlink_callback *cb)
 361 {
 362         struct net *net = sock_net(skb->sk);
 363         struct fib6_walker *w;
 364         int res;
 365
 366         w = (void *)cb->args[2];
 367         w->root = &table->tb6_root;
 368
 369         if (cb->args[4] == 0) {
 370                 w->count = 0;
 371                 w->skip = 0;
 372
 373                 read_lock_bh(&table->tb6_lock);
 374                 res = fib6_walk(net, w);
 375                 read_unlock_bh(&table->tb6_lock);
 376                 if (res > 0) {
 377                         cb->args[4] = 1;
 378                         cb->args[5] = w->root->fn_sernum;
 379                 }
 380         } else {
 381                 if (cb->args[5] != w->root->fn_sernum) {
 382                         /* Begin at the root if the tree changed */
 383                         cb->args[5] = w->root->fn_sernum;
 384                         w->state = FWS_INIT;
 385                         w->node = w->root;
 386                         w->skip = w->count;
 387                 } else
 388                         w->skip = 0;
 389
 390                 read_lock_bh(&table->tb6_lock);
 391                 res = fib6_walk_continue(w);
 392                 read_unlock_bh(&table->tb6_lock);
 393                 if (res <= 0) {
 394                         fib6_walker_unlink(net, w);
 395                         cb->args[4] = 0;
 396                 }
 397         }
 398
 399         return res;
 400 }
 401
 402 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 403 {
 404         struct net *net = sock_net(skb->sk);
 405         unsigned int h, s_h;
 406         unsigned int e = 0, s_e;
 407         struct rt6_rtnl_dump_arg arg;
 408         struct fib6_walker *w;
 409         struct fib6_table *tb;
 410         struct hlist_head *head;
 411         int res = 0;
 412
 413         s_h = cb->args[0];
 414         s_e = cb->args[1];
 415
 416         w = (void *)cb->args[2];
 417         if (!w) {
 418                 /* New dump:
 419                  *
 420                  * 1. hook callback destructor.
 421                  */
 422                 cb->args[3] = (long)cb->done;
 423                 cb->done = fib6_dump_done;
 424
 425                 /*
 426                  * 2. allocate and initialize walker.
 427                  */
 428                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 429                 if (!w)
 430                         return -ENOMEM;
 431                 w->func = fib6_dump_node;
 432                 cb->args[2] = (long)w;
 433         }
 434
 435         arg.skb = skb;
 436         arg.cb = cb;
 437         arg.net = net;
 438         w->args = &arg;
 439
 440         rcu_read_lock();
 441         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 442                 e = 0;
 443                 head = &net->ipv6.fib_table_hash[h];
 444                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 445                         if (e < s_e)
 446                                 goto next;
 447                         res = fib6_dump_table(tb, skb, cb);
 448                         if (res != 0)
 449                                 goto out;
 450 next:
 451                         e++;
 452                 }
 453         }
 454 out:
 455         rcu_read_unlock();
 456         cb->args[1] = e;
 457         cb->args[0] = h;
 458
 459         res = res < 0 ? res : skb->len;
 460         if (res <= 0)
 461                 fib6_dump_end(cb);
 462         return res;
 463 }
 464
 465 /*
 466  *      Routing Table
 467  *
 468  *      return the appropriate node for a routing tree "add" operation
 469  *      by either creating and inserting or by returning an existing
 470  *      node.
 471  */
 472
 473 static struct fib6_node *fib6_add_1(struct fib6_node *root,
 474                                      struct in6_addr *addr, int plen,
 475                                      int offset, int allow_create,
 476                                      int replace_required, int sernum)
 477 {
 478         struct fib6_node *fn, *in, *ln;
 479         struct fib6_node *pn = NULL;
 480         struct rt6key *key;
 481         int     bit;
 482         __be32  dir = 0;
 483
 484         RT6_TRACE("fib6_add_1\n");
 485
 486         /* insert node in tree */
 487
 488         fn = root;
 489
 490         do {
 491                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
 492
 493                 /*
 494                  *      Prefix match
 495                  */
 496                 if (plen < fn->fn_bit ||
 497                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 498                         if (!allow_create) {
 499                                 if (replace_required) {
 500                                         pr_warn("Can't replace route, no match found\n");
 501                                         return ERR_PTR(-ENOENT);
 502                                 }
 503                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 504                         }
 505                         goto insert_above;
 506                 }
 507
 508                 /*
 509                  *      Exact match ?
 510                  */
 511
 512                 if (plen == fn->fn_bit) {
 513                         /* clean up an intermediate node */
 514                         if (!(fn->fn_flags & RTN_RTINFO)) {
 515                                 rt6_release(fn->leaf);
 516                                 fn->leaf = NULL;
 517                         }
 518
 519                         fn->fn_sernum = sernum;
 520
 521                         return fn;
 522                 }
 523
 524                 /*
 525                  *      We have more bits to go
 526                  */
 527
 528                 /* Try to walk down on tree. */
 529                 fn->fn_sernum = sernum;
 530                 dir = addr_bit_set(addr, fn->fn_bit);
 531                 pn = fn;
 532                 fn = dir ? fn->right : fn->left;
 533         } while (fn);
 534
 535         if (!allow_create) {
 536                 /* We should not create new node because
 537                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 538                  * I assume it is safe to require NLM_F_CREATE when
 539                  * REPLACE flag is used! Later we may want to remove the
 540                  * check for replace_required, because according
 541                  * to netlink specification, NLM_F_CREATE
 542                  * MUST be specified if new route is created.
 543                  * That would keep IPv6 consistent with IPv4
 544                  */
 545                 if (replace_required) {
 546                         pr_warn("Can't replace route, no match found\n");
 547                         return ERR_PTR(-ENOENT);
 548                 }
 549                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 550         }
 551         /*
 552          *      We walked to the bottom of tree.
 553          *      Create new leaf node without children.
 554          */
 555
 556         ln = node_alloc();
 557
 558         if (!ln)
 559                 return ERR_PTR(-ENOMEM);
 560         ln->fn_bit = plen;
 561
 562         ln->parent = pn;
 563         ln->fn_sernum = sernum;
 564
 565         if (dir)
 566                 pn->right = ln;
 567         else
 568                 pn->left  = ln;
 569
 570         return ln;
 571
 572
 573 insert_above:
 574         /*
 575          * split since we don't have a common prefix anymore or
 576          * we have a less significant route.
 577          * we've to insert an intermediate node on the list
 578          * this new node will point to the one we need to create
 579          * and the current
 580          */
 581
 582         pn = fn->parent;
 583
 584         /* find 1st bit in difference between the 2 addrs.
 585
 586            See comment in __ipv6_addr_diff: bit may be an invalid value,
 587            but if it is >= plen, the value is ignored in any case.
 588          */
 589
 590         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 591
 592         /*
 593          *              (intermediate)[in]
 594          *                /        \
 595          *      (new leaf node)[ln] (old node)[fn]
 596          */
 597         if (plen > bit) {
 598                 in = node_alloc();
 599                 ln = node_alloc();
 600
 601                 if (!in || !ln) {
 602                         if (in)
 603                                 node_free(in);
 604                         if (ln)
 605                                 node_free(ln);
 606                         return ERR_PTR(-ENOMEM);
 607                 }
 608
 609                 /*
 610                  * new intermediate node.
 611                  * RTN_RTINFO will
 612                  * be off since that an address that chooses one of
 613                  * the branches would not match less specific routes
 614                  * in the other branch
 615                  */
 616
 617                 in->fn_bit = bit;
 618
 619                 in->parent = pn;
 620                 in->leaf = fn->leaf;
 621                 atomic_inc(&in->leaf->rt6i_ref);
 622
 623                 in->fn_sernum = sernum;
 624
 625                 /* update parent pointer */
 626                 if (dir)
 627                         pn->right = in;
 628                 else
 629                         pn->left  = in;
 630
 631                 ln->fn_bit = plen;
 632
 633                 ln->parent = in;
 634                 fn->parent = in;
 635
 636                 ln->fn_sernum = sernum;
 637
 638                 if (addr_bit_set(addr, bit)) {
 639                         in->right = ln;
 640                         in->left  = fn;
 641                 } else {
 642                         in->left  = ln;
 643                         in->right = fn;
 644                 }
 645         } else { /* plen <= bit */
 646
 647                 /*
 648                  *              (new leaf node)[ln]
 649                  *                /        \
 650                  *           (old node)[fn] NULL
 651                  */
 652
 653                 ln = node_alloc();
 654
 655                 if (!ln)
 656                         return ERR_PTR(-ENOMEM);
 657
 658                 ln->fn_bit = plen;
 659
 660                 ln->parent = pn;
 661
 662                 ln->fn_sernum = sernum;
 663
 664                 if (dir)
 665                         pn->right = ln;
 666                 else
 667                         pn->left  = ln;
 668
 669                 if (addr_bit_set(&key->addr, plen))
 670                         ln->right = fn;
 671                 else
 672                         ln->left  = fn;
 673
 674                 fn->parent = ln;
 675         }
 676         return ln;
 677 }
 678
 679 static bool rt6_qualify_for_ecmp(struct rt6_info *rt)
 680 {
 681         return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
 682                RTF_GATEWAY;
 683 }
 684
 685 static void fib6_copy_metrics(u32 *mp, const struct mx6_config *mxc)
 686 {
 687         int i;
 688
 689         for (i = 0; i < RTAX_MAX; i++) {
 690                 if (test_bit(i, mxc->mx_valid))
 691                         mp[i] = mxc->mx[i];
 692         }
 693 }
 694
 695 static int fib6_commit_metrics(struct dst_entry *dst, struct mx6_config *mxc)
 696 {
 697         if (!mxc->mx)
 698                 return 0;
 699
 700         if (dst->flags & DST_HOST) {
 701                 u32 *mp = dst_metrics_write_ptr(dst);
 702
 703                 if (unlikely(!mp))
 704                         return -ENOMEM;
 705
 706                 fib6_copy_metrics(mp, mxc);
 707         } else {
 708                 dst_init_metrics(dst, mxc->mx, false);
 709
 710                 /* We've stolen mx now. */
 711                 mxc->mx = NULL;
 712         }
 713
 714         return 0;
 715 }
 716
 717 static void fib6_purge_rt(struct rt6_info *rt, struct fib6_node *fn,
 718                           struct net *net)
 719 {
 720         if (atomic_read(&rt->rt6i_ref) != 1) {
 721                 /* This route is used as dummy address holder in some split
 722                  * nodes. It is not leaked, but it still holds other resources,
 723                  * which must be released in time. So, scan ascendant nodes
 724                  * and replace dummy references to this route with references
 725                  * to still alive ones.
 726                  */
 727                 while (fn) {
 728                         if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
 729                                 fn->leaf = fib6_find_prefix(net, fn);
 730                                 atomic_inc(&fn->leaf->rt6i_ref);
 731                                 rt6_release(rt);
 732                         }
 733                         fn = fn->parent;
 734                 }
 735                 /* No more references are possible at this point. */
 736                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
 737         }
 738 }
 739
 740 /*
 741  *      Insert routing information in a node.
 742  */
 743
 744 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 745                             struct nl_info *info, struct mx6_config *mxc)
 746 {
 747         struct rt6_info *iter = NULL;
 748         struct rt6_info **ins;
 749         struct rt6_info **fallback_ins = NULL;
 750         int replace = (info->nlh &&
 751                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 752         int add = (!info->nlh ||
 753                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
 754         int found = 0;
 755         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
 756         u16 nlflags = NLM_F_EXCL;
 757         int err;
 758
 759         if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))
 760                 nlflags |= NLM_F_APPEND;
 761
 762         ins = &fn->leaf;
 763
 764         for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
 765                 /*
 766                  *      Search for duplicates
 767                  */
 768
 769                 if (iter->rt6i_metric == rt->rt6i_metric) {
 770                         /*
 771                          *      Same priority level
 772                          */
 773                         if (info->nlh &&
 774                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
 775                                 return -EEXIST;
 776
 777                         nlflags &= ~NLM_F_EXCL;
 778                         if (replace) {
 779                                 if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
 780                                         found++;
 781                                         break;
 782                                 }
 783                                 if (rt_can_ecmp)
 784                                         fallback_ins = fallback_ins ?: ins;
 785                                 goto next_iter;
 786                         }
 787
 788                         if (iter->dst.dev == rt->dst.dev &&
 789                             iter->rt6i_idev == rt->rt6i_idev &&
 790                             ipv6_addr_equal(&iter->rt6i_gateway,
 791                                             &rt->rt6i_gateway)) {
 792                                 if (rt->rt6i_nsiblings)
 793                                         rt->rt6i_nsiblings = 0;
 794                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
 795                                         return -EEXIST;
 796                                 if (!(rt->rt6i_flags & RTF_EXPIRES))
 797                                         rt6_clean_expires(iter);
 798                                 else
 799                                         rt6_set_expires(iter, rt->dst.expires);
 800                                 iter->rt6i_pmtu = rt->rt6i_pmtu;
 801                                 return -EEXIST;
 802                         }
 803                         /* If we have the same destination and the same metric,
 804                          * but not the same gateway, then the route we try to
 805                          * add is sibling to this route, increment our counter
 806                          * of siblings, and later we will add our route to the
 807                          * list.
 808                          * Only static routes (which don't have flag
 809                          * RTF_EXPIRES) are used for ECMPv6.
 810                          *
 811                          * To avoid long list, we only had siblings if the
 812                          * route have a gateway.
 813                          */
 814                         if (rt_can_ecmp &&
 815                             rt6_qualify_for_ecmp(iter))
 816                                 rt->rt6i_nsiblings++;
 817                 }
 818
 819                 if (iter->rt6i_metric > rt->rt6i_metric)
 820                         break;
 821
 822 next_iter:
 823                 ins = &iter->dst.rt6_next;
 824         }
 825
 826         if (fallback_ins && !found) {
 827                 /* No ECMP-able route found, replace first non-ECMP one */
 828                 ins = fallback_ins;
 829                 iter = *ins;
 830                 found++;
 831         }
 832
 833         /* Reset round-robin state, if necessary */
 834         if (ins == &fn->leaf)
 835                 fn->rr_ptr = NULL;
 836
 837         /* Link this route to others same route. */
 838         if (rt->rt6i_nsiblings) {
 839                 unsigned int rt6i_nsiblings;
 840                 struct rt6_info *sibling, *temp_sibling;
 841
 842                 /* Find the first route that have the same metric */
 843                 sibling = fn->leaf;
 844                 while (sibling) {
 845                         if (sibling->rt6i_metric == rt->rt6i_metric &&
 846                             rt6_qualify_for_ecmp(sibling)) {
 847                                 list_add_tail(&rt->rt6i_siblings,
 848                                               &sibling->rt6i_siblings);
 849                                 break;
 850                         }
 851                         sibling = sibling->dst.rt6_next;
 852                 }
 853                 /* For each sibling in the list, increment the counter of
 854                  * siblings. BUG() if counters does not match, list of siblings
 855                  * is broken!
 856                  */
 857                 rt6i_nsiblings = 0;
 858                 list_for_each_entry_safe(sibling, temp_sibling,
 859                                          &rt->rt6i_siblings, rt6i_siblings) {
 860                         sibling->rt6i_nsiblings++;
 861                         BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
 862                         rt6i_nsiblings++;
 863                 }
 864                 BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
 865         }
 866
 867         /*
 868          *      insert node
 869          */
 870         if (!replace) {
 871                 if (!add)
 872                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
 873
 874 add:
 875                 nlflags |= NLM_F_CREATE;
 876                 err = fib6_commit_metrics(&rt->dst, mxc);
 877                 if (err)
 878                         return err;
 879
 880                 rt->dst.rt6_next = iter;
 881                 *ins = rt;
 882                 rt->rt6i_node = fn;
 883                 atomic_inc(&rt->rt6i_ref);
 884                 if (!info->skip_notify)
 885                         inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
 886                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 887
 888                 if (!(fn->fn_flags & RTN_RTINFO)) {
 889                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 890                         fn->fn_flags |= RTN_RTINFO;
 891                 }
 892
 893         } else {
 894                 int nsiblings;
 895
 896                 if (!found) {
 897                         if (add)
 898                                 goto add;
 899                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
 900                         return -ENOENT;
 901                 }
 902
 903                 err = fib6_commit_metrics(&rt->dst, mxc);
 904                 if (err)
 905                         return err;
 906
 907                 *ins = rt;
 908                 rt->rt6i_node = fn;
 909                 rt->dst.rt6_next = iter->dst.rt6_next;
 910                 atomic_inc(&rt->rt6i_ref);
 911                 if (!info->skip_notify)
 912                         inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
 913                 if (!(fn->fn_flags & RTN_RTINFO)) {
 914                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 915                         fn->fn_flags |= RTN_RTINFO;
 916                 }
 917                 nsiblings = iter->rt6i_nsiblings;
 918                 fib6_purge_rt(iter, fn, info->nl_net);
 919                 rt6_release(iter);
 920
 921                 if (nsiblings) {
 922                         /* Replacing an ECMP route, remove all siblings */
 923                         ins = &rt->dst.rt6_next;
 924                         iter = *ins;
 925                         while (iter) {
 926                                 if (iter->rt6i_metric > rt->rt6i_metric)
 927                                         break;
 928                                 if (rt6_qualify_for_ecmp(iter)) {
 929                                         *ins = iter->dst.rt6_next;
 930                                         fib6_purge_rt(iter, fn, info->nl_net);
 931                                         rt6_release(iter);
 932                                         nsiblings--;
 933                                 } else {
 934                                         ins = &iter->dst.rt6_next;
 935                                 }
 936                                 iter = *ins;
 937                         }
 938                         WARN_ON(nsiblings != 0);
 939                 }
 940         }
 941
 942         return 0;
 943 }
 944
 945 static void fib6_start_gc(struct net *net, struct rt6_info *rt)
 946 {
 947         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 948             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 949                 mod_timer(&net->ipv6.ip6_fib_timer,
 950                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 951 }
 952
 953 void fib6_force_start_gc(struct net *net)
 954 {
 955         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 956                 mod_timer(&net->ipv6.ip6_fib_timer,
 957                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 958 }
 959
 960 /*
 961  *      Add routing information to the routing tree.
 962  *      <destination addr>/<source addr>
 963  *      with source addr info in sub-trees
 964  */
 965
 966 int fib6_add(struct fib6_node *root, struct rt6_info *rt,
 967              struct nl_info *info, struct mx6_config *mxc)
 968 {
 969         struct fib6_node *fn, *pn = NULL;
 970         int err = -ENOMEM;
 971         int allow_create = 1;
 972         int replace_required = 0;
 973         int sernum = fib6_new_sernum(info->nl_net);
 974
 975         if (WARN_ON_ONCE((rt->dst.flags & DST_NOCACHE) &&
 976                          !atomic_read(&rt->dst.__refcnt)))
 977                 return -EINVAL;
 978
 979         if (info->nlh) {
 980                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 981                         allow_create = 0;
 982                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 983                         replace_required = 1;
 984         }
 985         if (!allow_create && !replace_required)
 986                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 987
 988         fn = fib6_add_1(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
 989                         offsetof(struct rt6_info, rt6i_dst), allow_create,
 990                         replace_required, sernum);
 991         if (IS_ERR(fn)) {
 992                 err = PTR_ERR(fn);
 993                 fn = NULL;
 994                 goto out;
 995         }
 996
 997         pn = fn;
 998
 999 #ifdef CONFIG_IPV6_SUBTREES
1000         if (rt->rt6i_src.plen) {
1001                 struct fib6_node *sn;
1002
1003                 if (!fn->subtree) {
1004                         struct fib6_node *sfn;
1005
1006                         /*
1007                          * Create subtree.
1008                          *
1009                          *              fn[main tree]
1010                          *              |
1011                          *              sfn[subtree root]
1012                          *                 \
1013                          *                  sn[new leaf node]
1014                          */
1015
1016                         /* Create subtree root node */
1017                         sfn = node_alloc();
1018                         if (!sfn)
1019                                 goto st_failure;
1020
1021                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
1022                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
1023                         sfn->fn_flags = RTN_ROOT;
1024                         sfn->fn_sernum = sernum;
1025
1026                         /* Now add the first leaf node to new subtree */
1027
1028                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
1029                                         rt->rt6i_src.plen,
1030                                         offsetof(struct rt6_info, rt6i_src),
1031                                         allow_create, replace_required, sernum);
1032
1033                         if (IS_ERR(sn)) {
1034                                 /* If it is failed, discard just allocated
1035                                    root, and then (in st_failure) stale node
1036                                    in main tree.
1037                                  */
1038                                 node_free(sfn);
1039                                 err = PTR_ERR(sn);
1040                                 goto st_failure;
1041                         }
1042
1043                         /* Now link new subtree to main tree */
1044                         sfn->parent = fn;
1045                         fn->subtree = sfn;
1046                 } else {
1047                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
1048                                         rt->rt6i_src.plen,
1049                                         offsetof(struct rt6_info, rt6i_src),
1050                                         allow_create, replace_required, sernum);
1051
1052                         if (IS_ERR(sn)) {
1053                                 err = PTR_ERR(sn);
1054                                 goto st_failure;
1055                         }
1056                 }
1057
1058                 if (!fn->leaf) {
1059                         fn->leaf = rt;
1060                         atomic_inc(&rt->rt6i_ref);
1061                 }
1062                 fn = sn;
1063         }
1064 #endif
1065
1066         err = fib6_add_rt2node(fn, rt, info, mxc);
1067         if (!err) {
1068                 fib6_start_gc(info->nl_net, rt);
1069                 if (!(rt->rt6i_flags & RTF_CACHE))
1070                         fib6_prune_clones(info->nl_net, pn);
1071                 rt->dst.flags &= ~DST_NOCACHE;
1072         }
1073
1074 out:
1075         if (err) {
1076 #ifdef CONFIG_IPV6_SUBTREES
1077                 /*
1078                  * If fib6_add_1 has cleared the old leaf pointer in the
1079                  * super-tree leaf node we have to find a new one for it.
1080                  */
1081                 if (pn != fn && pn->leaf == rt) {
1082                         pn->leaf = NULL;
1083                         atomic_dec(&rt->rt6i_ref);
1084                 }
1085                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
1086                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
1087 #if RT6_DEBUG >= 2
1088                         if (!pn->leaf) {
1089                                 WARN_ON(pn->leaf == NULL);
1090                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
1091                         }
1092 #endif
1093                         atomic_inc(&pn->leaf->rt6i_ref);
1094                 }
1095 #endif
1096                 if (!(rt->dst.flags & DST_NOCACHE))
1097                         dst_free(&rt->dst);
1098         }
1099         return err;
1100
1101 #ifdef CONFIG_IPV6_SUBTREES
1102         /* Subtree creation failed, probably main tree node
1103            is orphan. If it is, shoot it.
1104          */
1105 st_failure:
1106         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
1107                 fib6_repair_tree(info->nl_net, fn);
1108         if (!(rt->dst.flags & DST_NOCACHE))
1109                 dst_free(&rt->dst);
1110         return err;
1111 #endif
1112 }
1113
1114 /*
1115  *      Routing tree lookup
1116  *
1117  */
1118
1119 struct lookup_args {
1120         int                     offset;         /* key offset on rt6_info       */
1121         const struct in6_addr   *addr;          /* search key                   */
1122 };
1123
1124 static struct fib6_node *fib6_lookup_1(struct fib6_node *root,
1125                                        struct lookup_args *args)
1126 {
1127         struct fib6_node *fn;
1128         __be32 dir;
1129
1130         if (unlikely(args->offset == 0))
1131                 return NULL;
1132
1133         /*
1134          *      Descend on a tree
1135          */
1136
1137         fn = root;
1138
1139         for (;;) {
1140                 struct fib6_node *next;
1141
1142                 dir = addr_bit_set(args->addr, fn->fn_bit);
1143
1144                 next = dir ? fn->right : fn->left;
1145
1146                 if (next) {
1147                         fn = next;
1148                         continue;
1149                 }
1150                 break;
1151         }
1152
1153         while (fn) {
1154                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
1155                         struct rt6key *key;
1156
1157                         key = (struct rt6key *) ((u8 *) fn->leaf +
1158                                                  args->offset);
1159
1160                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1161 #ifdef CONFIG_IPV6_SUBTREES
1162                                 if (fn->subtree) {
1163                                         struct fib6_node *sfn;
1164                                         sfn = fib6_lookup_1(fn->subtree,
1165                                                             args + 1);
1166                                         if (!sfn)
1167                                                 goto backtrack;
1168                                         fn = sfn;
1169                                 }
1170 #endif
1171                                 if (fn->fn_flags & RTN_RTINFO)
1172                                         return fn;
1173                         }
1174                 }
1175 #ifdef CONFIG_IPV6_SUBTREES
1176 backtrack:
1177 #endif
1178                 if (fn->fn_flags & RTN_ROOT)
1179                         break;
1180
1181                 fn = fn->parent;
1182         }
1183
1184         return NULL;
1185 }
1186
1187 struct fib6_node *fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
1188                               const struct in6_addr *saddr)
1189 {
1190         struct fib6_node *fn;
1191         struct lookup_args args[] = {
1192                 {
1193                         .offset = offsetof(struct rt6_info, rt6i_dst),
1194                         .addr = daddr,
1195                 },
1196 #ifdef CONFIG_IPV6_SUBTREES
1197                 {
1198                         .offset = offsetof(struct rt6_info, rt6i_src),
1199                         .addr = saddr,
1200                 },
1201 #endif
1202                 {
1203                         .offset = 0,    /* sentinel */
1204                 }
1205         };
1206
1207         fn = fib6_lookup_1(root, daddr ? args : args + 1);
1208         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1209                 fn = root;
1210
1211         return fn;
1212 }
1213
1214 /*
1215  *      Get node with specified destination prefix (and source prefix,
1216  *      if subtrees are used)
1217  */
1218
1219
1220 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1221                                        const struct in6_addr *addr,
1222                                        int plen, int offset)
1223 {
1224         struct fib6_node *fn;
1225
1226         for (fn = root; fn ; ) {
1227                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1228
1229                 /*
1230                  *      Prefix match
1231                  */
1232                 if (plen < fn->fn_bit ||
1233                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1234                         return NULL;
1235
1236                 if (plen == fn->fn_bit)
1237                         return fn;
1238
1239                 /*
1240                  *      We have more bits to go
1241                  */
1242                 if (addr_bit_set(addr, fn->fn_bit))
1243                         fn = fn->right;
1244                 else
1245                         fn = fn->left;
1246         }
1247         return NULL;
1248 }
1249
1250 struct fib6_node *fib6_locate(struct fib6_node *root,
1251                               const struct in6_addr *daddr, int dst_len,
1252                               const struct in6_addr *saddr, int src_len)
1253 {
1254         struct fib6_node *fn;
1255
1256         fn = fib6_locate_1(root, daddr, dst_len,
1257                            offsetof(struct rt6_info, rt6i_dst));
1258
1259 #ifdef CONFIG_IPV6_SUBTREES
1260         if (src_len) {
1261                 WARN_ON(saddr == NULL);
1262                 if (fn && fn->subtree)
1263                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
1264                                            offsetof(struct rt6_info, rt6i_src));
1265         }
1266 #endif
1267
1268         if (fn && fn->fn_flags & RTN_RTINFO)
1269                 return fn;
1270
1271         return NULL;
1272 }
1273
1274
1275 /*
1276  *      Deletion
1277  *
1278  */
1279
1280 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1281 {
1282         if (fn->fn_flags & RTN_ROOT)
1283                 return net->ipv6.ip6_null_entry;
1284
1285         while (fn) {
1286                 if (fn->left)
1287                         return fn->left->leaf;
1288                 if (fn->right)
1289                         return fn->right->leaf;
1290
1291                 fn = FIB6_SUBTREE(fn);
1292         }
1293         return NULL;
1294 }
1295
1296 /*
1297  *      Called to trim the tree of intermediate nodes when possible. "fn"
1298  *      is the node we want to try and remove.
1299  */
1300
1301 static struct fib6_node *fib6_repair_tree(struct net *net,
1302                                            struct fib6_node *fn)
1303 {
1304         int children;
1305         int nstate;
1306         struct fib6_node *child, *pn;
1307         struct fib6_walker *w;
1308         int iter = 0;
1309
1310         for (;;) {
1311                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1312                 iter++;
1313
1314                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1315                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1316                 WARN_ON(fn->leaf);
1317
1318                 children = 0;
1319                 child = NULL;
1320                 if (fn->right)
1321                         child = fn->right, children |= 1;
1322                 if (fn->left)
1323                         child = fn->left, children |= 2;
1324
1325                 if (children == 3 || FIB6_SUBTREE(fn)
1326 #ifdef CONFIG_IPV6_SUBTREES
1327                     /* Subtree root (i.e. fn) may have one child */
1328                     || (children && fn->fn_flags & RTN_ROOT)
1329 #endif
1330                     ) {
1331                         fn->leaf = fib6_find_prefix(net, fn);
1332 #if RT6_DEBUG >= 2
1333                         if (!fn->leaf) {
1334                                 WARN_ON(!fn->leaf);
1335                                 fn->leaf = net->ipv6.ip6_null_entry;
1336                         }
1337 #endif
1338                         atomic_inc(&fn->leaf->rt6i_ref);
1339                         return fn->parent;
1340                 }
1341
1342                 pn = fn->parent;
1343 #ifdef CONFIG_IPV6_SUBTREES
1344                 if (FIB6_SUBTREE(pn) == fn) {
1345                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1346                         FIB6_SUBTREE(pn) = NULL;
1347                         nstate = FWS_L;
1348                 } else {
1349                         WARN_ON(fn->fn_flags & RTN_ROOT);
1350 #endif
1351                         if (pn->right == fn)
1352                                 pn->right = child;
1353                         else if (pn->left == fn)
1354                                 pn->left = child;
1355 #if RT6_DEBUG >= 2
1356                         else
1357                                 WARN_ON(1);
1358 #endif
1359                         if (child)
1360                                 child->parent = pn;
1361                         nstate = FWS_R;
1362 #ifdef CONFIG_IPV6_SUBTREES
1363                 }
1364 #endif
1365
1366                 read_lock(&net->ipv6.fib6_walker_lock);
1367                 FOR_WALKERS(net, w) {
1368                         if (!child) {
1369                                 if (w->root == fn) {
1370                                         w->root = w->node = NULL;
1371                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1372                                 } else if (w->node == fn) {
1373                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1374                                         w->node = pn;
1375                                         w->state = nstate;
1376                                 }
1377                         } else {
1378                                 if (w->root == fn) {
1379                                         w->root = child;
1380                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1381                                 }
1382                                 if (w->node == fn) {
1383                                         w->node = child;
1384                                         if (children&2) {
1385                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1386                                                 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1387                                         } else {
1388                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1389                                                 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1390                                         }
1391                                 }
1392                         }
1393                 }
1394                 read_unlock(&net->ipv6.fib6_walker_lock);
1395
1396                 node_free(fn);
1397                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1398                         return pn;
1399
1400                 rt6_release(pn->leaf);
1401                 pn->leaf = NULL;
1402                 fn = pn;
1403         }
1404 }
1405
1406 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1407                            struct nl_info *info)
1408 {
1409         struct fib6_walker *w;
1410         struct rt6_info *rt = *rtp;
1411         struct net *net = info->nl_net;
1412
1413         RT6_TRACE("fib6_del_route\n");
1414
1415         /* Unlink it */
1416         *rtp = rt->dst.rt6_next;
1417         rt->rt6i_node = NULL;
1418         net->ipv6.rt6_stats->fib_rt_entries--;
1419         net->ipv6.rt6_stats->fib_discarded_routes++;
1420
1421         /* Reset round-robin state, if necessary */
1422         if (fn->rr_ptr == rt)
1423                 fn->rr_ptr = NULL;
1424
1425         /* Remove this entry from other siblings */
1426         if (rt->rt6i_nsiblings) {
1427                 struct rt6_info *sibling, *next_sibling;
1428
1429                 list_for_each_entry_safe(sibling, next_sibling,
1430                                          &rt->rt6i_siblings, rt6i_siblings)
1431                         sibling->rt6i_nsiblings--;
1432                 rt->rt6i_nsiblings = 0;
1433                 list_del_init(&rt->rt6i_siblings);
1434         }
1435
1436         /* Adjust walkers */
1437         read_lock(&net->ipv6.fib6_walker_lock);
1438         FOR_WALKERS(net, w) {
1439                 if (w->state == FWS_C && w->leaf == rt) {
1440                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1441                         w->leaf = rt->dst.rt6_next;
1442                         if (!w->leaf)
1443                                 w->state = FWS_U;
1444                 }
1445         }
1446         read_unlock(&net->ipv6.fib6_walker_lock);
1447
1448         rt->dst.rt6_next = NULL;
1449
1450         /* If it was last route, expunge its radix tree node */
1451         if (!fn->leaf) {
1452                 fn->fn_flags &= ~RTN_RTINFO;
1453                 net->ipv6.rt6_stats->fib_route_nodes--;
1454                 fn = fib6_repair_tree(net, fn);
1455         }
1456
1457         fib6_purge_rt(rt, fn, net);
1458
1459         if (!info->skip_notify)
1460                 inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
1461         rt6_release(rt);
1462 }
1463
1464 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1465 {
1466         struct net *net = info->nl_net;
1467         struct fib6_node *fn = rt->rt6i_node;
1468         struct rt6_info **rtp;
1469
1470 #if RT6_DEBUG >= 2
1471         if (rt->dst.obsolete > 0) {
1472                 WARN_ON(fn);
1473                 return -ENOENT;
1474         }
1475 #endif
1476         if (!fn || rt == net->ipv6.ip6_null_entry)
1477                 return -ENOENT;
1478
1479         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1480
1481         if (!(rt->rt6i_flags & RTF_CACHE)) {
1482                 struct fib6_node *pn = fn;
1483 #ifdef CONFIG_IPV6_SUBTREES
1484                 /* clones of this route might be in another subtree */
1485                 if (rt->rt6i_src.plen) {
1486                         while (!(pn->fn_flags & RTN_ROOT))
1487                                 pn = pn->parent;
1488                         pn = pn->parent;
1489                 }
1490 #endif
1491                 fib6_prune_clones(info->nl_net, pn);
1492         }
1493
1494         /*
1495          *      Walk the leaf entries looking for ourself
1496          */
1497
1498         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1499                 if (*rtp == rt) {
1500                         fib6_del_route(fn, rtp, info);
1501                         return 0;
1502                 }
1503         }
1504         return -ENOENT;
1505 }
1506
1507 /*
1508  *      Tree traversal function.
1509  *
1510  *      Certainly, it is not interrupt safe.
1511  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1512  *      It means, that we can modify tree during walking
1513  *      and use this function for garbage collection, clone pruning,
1514  *      cleaning tree when a device goes down etc. etc.
1515  *
1516  *      It guarantees that every node will be traversed,
1517  *      and that it will be traversed only once.
1518  *
1519  *      Callback function w->func may return:
1520  *      0 -> continue walking.
1521  *      positive value -> walking is suspended (used by tree dumps,
1522  *      and probably by gc, if it will be split to several slices)
1523  *      negative value -> terminate walking.
1524  *
1525  *      The function itself returns:
1526  *      0   -> walk is complete.
1527  *      >0  -> walk is incomplete (i.e. suspended)
1528  *      <0  -> walk is terminated by an error.
1529  */
1530
1531 static int fib6_walk_continue(struct fib6_walker *w)
1532 {
1533         struct fib6_node *fn, *pn;
1534
1535         for (;;) {
1536                 fn = w->node;
1537                 if (!fn)
1538                         return 0;
1539
1540                 if (w->prune && fn != w->root &&
1541                     fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1542                         w->state = FWS_C;
1543                         w->leaf = fn->leaf;
1544                 }
1545                 switch (w->state) {
1546 #ifdef CONFIG_IPV6_SUBTREES
1547                 case FWS_S:
1548                         if (FIB6_SUBTREE(fn)) {
1549                                 w->node = FIB6_SUBTREE(fn);
1550                                 continue;
1551                         }
1552                         w->state = FWS_L;
1553 #endif
1554                 case FWS_L:
1555                         if (fn->left) {
1556                                 w->node = fn->left;
1557                                 w->state = FWS_INIT;
1558                                 continue;
1559                         }
1560                         w->state = FWS_R;
1561                 case FWS_R:
1562                         if (fn->right) {
1563                                 w->node = fn->right;
1564                                 w->state = FWS_INIT;
1565                                 continue;
1566                         }
1567                         w->state = FWS_C;
1568                         w->leaf = fn->leaf;
1569                 case FWS_C:
1570                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1571                                 int err;
1572
1573                                 if (w->skip) {
1574                                         w->skip--;
1575                                         goto skip;
1576                                 }
1577
1578                                 err = w->func(w);
1579                                 if (err)
1580                                         return err;
1581
1582                                 w->count++;
1583                                 continue;
1584                         }
1585 skip:
1586                         w->state = FWS_U;
1587                 case FWS_U:
1588                         if (fn == w->root)
1589                                 return 0;
1590                         pn = fn->parent;
1591                         w->node = pn;
1592 #ifdef CONFIG_IPV6_SUBTREES
1593                         if (FIB6_SUBTREE(pn) == fn) {
1594                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1595                                 w->state = FWS_L;
1596                                 continue;
1597                         }
1598 #endif
1599                         if (pn->left == fn) {
1600                                 w->state = FWS_R;
1601                                 continue;
1602                         }
1603                         if (pn->right == fn) {
1604                                 w->state = FWS_C;
1605                                 w->leaf = w->node->leaf;
1606                                 continue;
1607                         }
1608 #if RT6_DEBUG >= 2
1609                         WARN_ON(1);
1610 #endif
1611                 }
1612         }
1613 }
1614
1615 static int fib6_walk(struct net *net, struct fib6_walker *w)
1616 {
1617         int res;
1618
1619         w->state = FWS_INIT;
1620         w->node = w->root;
1621
1622         fib6_walker_link(net, w);
1623         res = fib6_walk_continue(w);
1624         if (res <= 0)
1625                 fib6_walker_unlink(net, w);
1626         return res;
1627 }
1628
1629 static int fib6_clean_node(struct fib6_walker *w)
1630 {
1631         int res;
1632         struct rt6_info *rt;
1633         struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
1634         struct nl_info info = {
1635                 .nl_net = c->net,
1636         };
1637
1638         if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
1639             w->node->fn_sernum != c->sernum)
1640                 w->node->fn_sernum = c->sernum;
1641
1642         if (!c->func) {
1643                 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
1644                 w->leaf = NULL;
1645                 return 0;
1646         }
1647
1648         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1649                 res = c->func(rt, c->arg);
1650                 if (res < 0) {
1651                         w->leaf = rt;
1652                         res = fib6_del(rt, &info);
1653                         if (res) {
1654 #if RT6_DEBUG >= 2
1655                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1656                                          __func__, rt, rt->rt6i_node, res);
1657 #endif
1658                                 continue;
1659                         }
1660                         return 0;
1661                 }
1662                 WARN_ON(res != 0);
1663         }
1664         w->leaf = rt;
1665         return 0;
1666 }
1667
1668 /*
1669  *      Convenient frontend to tree walker.
1670  *
1671  *      func is called on each route.
1672  *              It may return -1 -> delete this route.
1673  *                            0  -> continue walking
1674  *
1675  *      prune==1 -> only immediate children of node (certainly,
1676  *      ignoring pure split nodes) will be scanned.
1677  */
1678
1679 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1680                             int (*func)(struct rt6_info *, void *arg),
1681                             bool prune, int sernum, void *arg)
1682 {
1683         struct fib6_cleaner c;
1684
1685         c.w.root = root;
1686         c.w.func = fib6_clean_node;
1687         c.w.prune = prune;
1688         c.w.count = 0;
1689         c.w.skip = 0;
1690         c.func = func;
1691         c.sernum = sernum;
1692         c.arg = arg;
1693         c.net = net;
1694
1695         fib6_walk(net, &c.w);
1696 }
1697
1698 static void __fib6_clean_all(struct net *net,
1699                              int (*func)(struct rt6_info *, void *),
1700                              int sernum, void *arg)
1701 {
1702         struct fib6_table *table;
1703         struct hlist_head *head;
1704         unsigned int h;
1705
1706         rcu_read_lock();
1707         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1708                 head = &net->ipv6.fib_table_hash[h];
1709                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1710                         write_lock_bh(&table->tb6_lock);
1711                         fib6_clean_tree(net, &table->tb6_root,
1712                                         func, false, sernum, arg);
1713                         write_unlock_bh(&table->tb6_lock);
1714                 }
1715         }
1716         rcu_read_unlock();
1717 }
1718
1719 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *),
1720                     void *arg)
1721 {
1722         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
1723 }
1724
1725 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1726 {
1727         if (rt->rt6i_flags & RTF_CACHE) {
1728                 RT6_TRACE("pruning clone %p\n", rt);
1729                 return -1;
1730         }
1731
1732         return 0;
1733 }
1734
1735 static void fib6_prune_clones(struct net *net, struct fib6_node *fn)
1736 {
1737         fib6_clean_tree(net, fn, fib6_prune_clone, true,
1738                         FIB6_NO_SERNUM_CHANGE, NULL);
1739 }
1740
1741 static void fib6_flush_trees(struct net *net)
1742 {
1743         int new_sernum = fib6_new_sernum(net);
1744
1745         __fib6_clean_all(net, NULL, new_sernum, NULL);
1746 }
1747
1748 /*
1749  *      Garbage collection
1750  */
1751
1752 struct fib6_gc_args
1753 {
1754         int                     timeout;
1755         int                     more;
1756 };
1757
1758 static int fib6_age(struct rt6_info *rt, void *arg)
1759 {
1760         struct fib6_gc_args *gc_args = arg;
1761         unsigned long now = jiffies;
1762
1763         /*
1764          *      check addrconf expiration here.
1765          *      Routes are expired even if they are in use.
1766          *
1767          *      Also age clones. Note, that clones are aged out
1768          *      only if they are not in use now.
1769          */
1770
1771         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1772                 if (time_after(now, rt->dst.expires)) {
1773                         RT6_TRACE("expiring %p\n", rt);
1774                         return -1;
1775                 }
1776                 gc_args->more++;
1777         } else if (rt->rt6i_flags & RTF_CACHE) {
1778                 if (atomic_read(&rt->dst.__refcnt) == 0 &&
1779                     time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
1780                         RT6_TRACE("aging clone %p\n", rt);
1781                         return -1;
1782                 } else if (rt->rt6i_flags & RTF_GATEWAY) {
1783                         struct neighbour *neigh;
1784                         __u8 neigh_flags = 0;
1785
1786                         neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1787                         if (neigh) {
1788                                 neigh_flags = neigh->flags;
1789                                 neigh_release(neigh);
1790                         }
1791                         if (!(neigh_flags & NTF_ROUTER)) {
1792                                 RT6_TRACE("purging route %p via non-router but gateway\n",
1793                                           rt);
1794                                 return -1;
1795                         }
1796                 }
1797                 gc_args->more++;
1798         }
1799
1800         return 0;
1801 }
1802
1803 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
1804 {
1805         struct fib6_gc_args gc_args;
1806         unsigned long now;
1807
1808         if (force) {
1809                 spin_lock_bh(&net->ipv6.fib6_gc_lock);
1810         } else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
1811                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1812                 return;
1813         }
1814         gc_args.timeout = expires ? (int)expires :
1815                           net->ipv6.sysctl.ip6_rt_gc_interval;
1816
1817         gc_args.more = icmp6_dst_gc();
1818
1819         fib6_clean_all(net, fib6_age, &gc_args);
1820         now = jiffies;
1821         net->ipv6.ip6_rt_last_gc = now;
1822
1823         if (gc_args.more)
1824                 mod_timer(&net->ipv6.ip6_fib_timer,
1825                           round_jiffies(now
1826                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1827         else
1828                 del_timer(&net->ipv6.ip6_fib_timer);
1829         spin_unlock_bh(&net->ipv6.fib6_gc_lock);
1830 }
1831
1832 static void fib6_gc_timer_cb(unsigned long arg)
1833 {
1834         fib6_run_gc(0, (struct net *)arg, true);
1835 }
1836
1837 static int __net_init fib6_net_init(struct net *net)
1838 {
1839         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1840
1841         spin_lock_init(&net->ipv6.fib6_gc_lock);
1842         rwlock_init(&net->ipv6.fib6_walker_lock);
1843         INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
1844         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1845
1846         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1847         if (!net->ipv6.rt6_stats)
1848                 goto out_timer;
1849
1850         /* Avoid false sharing : Use at least a full cache line */
1851         size = max_t(size_t, size, L1_CACHE_BYTES);
1852
1853         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1854         if (!net->ipv6.fib_table_hash)
1855                 goto out_rt6_stats;
1856
1857         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1858                                           GFP_KERNEL);
1859         if (!net->ipv6.fib6_main_tbl)
1860                 goto out_fib_table_hash;
1861
1862         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1863         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1864         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1865                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1866         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1867
1868 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1869         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1870                                            GFP_KERNEL);
1871         if (!net->ipv6.fib6_local_tbl)
1872                 goto out_fib6_main_tbl;
1873         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1874         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1875         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1876                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1877         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1878 #endif
1879         fib6_tables_init(net);
1880
1881         return 0;
1882
1883 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1884 out_fib6_main_tbl:
1885         kfree(net->ipv6.fib6_main_tbl);
1886 #endif
1887 out_fib_table_hash:
1888         kfree(net->ipv6.fib_table_hash);
1889 out_rt6_stats:
1890         kfree(net->ipv6.rt6_stats);
1891 out_timer:
1892         return -ENOMEM;
1893 }
1894
1895 static void fib6_net_exit(struct net *net)
1896 {
1897         rt6_ifdown(net, NULL);
1898         del_timer_sync(&net->ipv6.ip6_fib_timer);
1899
1900 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1901         inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1902         kfree(net->ipv6.fib6_local_tbl);
1903 #endif
1904         inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1905         kfree(net->ipv6.fib6_main_tbl);
1906         kfree(net->ipv6.fib_table_hash);
1907         kfree(net->ipv6.rt6_stats);
1908 }
1909
1910 static struct pernet_operations fib6_net_ops = {
1911         .init = fib6_net_init,
1912         .exit = fib6_net_exit,
1913 };
1914
1915 int __init fib6_init(void)
1916 {
1917         int ret = -ENOMEM;
1918
1919         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1920                                            sizeof(struct fib6_node),
1921                                            0, SLAB_HWCACHE_ALIGN,
1922                                            NULL);
1923         if (!fib6_node_kmem)
1924                 goto out;
1925
1926         ret = register_pernet_subsys(&fib6_net_ops);
1927         if (ret)
1928                 goto out_kmem_cache_create;
1929
1930         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1931                               NULL);
1932         if (ret)
1933                 goto out_unregister_subsys;
1934
1935         __fib6_flush_trees = fib6_flush_trees;
1936 out:
1937         return ret;
1938
1939 out_unregister_subsys:
1940         unregister_pernet_subsys(&fib6_net_ops);
1941 out_kmem_cache_create:
1942         kmem_cache_destroy(fib6_node_kmem);
1943         goto out;
1944 }
1945
1946 void fib6_gc_cleanup(void)
1947 {
1948         unregister_pernet_subsys(&fib6_net_ops);
1949         kmem_cache_destroy(fib6_node_kmem);
1950 }
1951
1952 #ifdef CONFIG_PROC_FS
1953
1954 struct ipv6_route_iter {
1955         struct seq_net_private p;
1956         struct fib6_walker w;
1957         loff_t skip;
1958         struct fib6_table *tbl;
1959         int sernum;
1960 };
1961
1962 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
1963 {
1964         struct rt6_info *rt = v;
1965         struct ipv6_route_iter *iter = seq->private;
1966
1967         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
1968
1969 #ifdef CONFIG_IPV6_SUBTREES
1970         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
1971 #else
1972         seq_puts(seq, "00000000000000000000000000000000 00 ");
1973 #endif
1974         if (rt->rt6i_flags & RTF_GATEWAY)
1975                 seq_printf(seq, "%pi6", &rt->rt6i_gateway);
1976         else
1977                 seq_puts(seq, "00000000000000000000000000000000");
1978
1979         seq_printf(seq, " %08x %08x %08x %08x %8s\n",
1980                    rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
1981                    rt->dst.__use, rt->rt6i_flags,
1982                    rt->dst.dev ? rt->dst.dev->name : "");
1983         iter->w.leaf = NULL;
1984         return 0;
1985 }
1986
1987 static int ipv6_route_yield(struct fib6_walker *w)
1988 {
1989         struct ipv6_route_iter *iter = w->args;
1990
1991         if (!iter->skip)
1992                 return 1;
1993
1994         do {
1995                 iter->w.leaf = iter->w.leaf->dst.rt6_next;
1996                 iter->skip--;
1997                 if (!iter->skip && iter->w.leaf)
1998                         return 1;
1999         } while (iter->w.leaf);
2000
2001         return 0;
2002 }
2003
2004 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
2005                                       struct net *net)
2006 {
2007         memset(&iter->w, 0, sizeof(iter->w));
2008         iter->w.func = ipv6_route_yield;
2009         iter->w.root = &iter->tbl->tb6_root;
2010         iter->w.state = FWS_INIT;
2011         iter->w.node = iter->w.root;
2012         iter->w.args = iter;
2013         iter->sernum = iter->w.root->fn_sernum;
2014         INIT_LIST_HEAD(&iter->w.lh);
2015         fib6_walker_link(net, &iter->w);
2016 }
2017
2018 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
2019                                                     struct net *net)
2020 {
2021         unsigned int h;
2022         struct hlist_node *node;
2023
2024         if (tbl) {
2025                 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
2026                 node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
2027         } else {
2028                 h = 0;
2029                 node = NULL;
2030         }
2031
2032         while (!node && h < FIB6_TABLE_HASHSZ) {
2033                 node = rcu_dereference_bh(
2034                         hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
2035         }
2036         return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
2037 }
2038
2039 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
2040 {
2041         if (iter->sernum != iter->w.root->fn_sernum) {
2042                 iter->sernum = iter->w.root->fn_sernum;
2043                 iter->w.state = FWS_INIT;
2044                 iter->w.node = iter->w.root;
2045                 WARN_ON(iter->w.skip);
2046                 iter->w.skip = iter->w.count;
2047         }
2048 }
2049
2050 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2051 {
2052         int r;
2053         struct rt6_info *n;
2054         struct net *net = seq_file_net(seq);
2055         struct ipv6_route_iter *iter = seq->private;
2056
2057         if (!v)
2058                 goto iter_table;
2059
2060         n = ((struct rt6_info *)v)->dst.rt6_next;
2061         if (n) {
2062                 ++*pos;
2063                 return n;
2064         }
2065
2066 iter_table:
2067         ipv6_route_check_sernum(iter);
2068         read_lock(&iter->tbl->tb6_lock);
2069         r = fib6_walk_continue(&iter->w);
2070         read_unlock(&iter->tbl->tb6_lock);
2071         if (r > 0) {
2072                 if (v)
2073                         ++*pos;
2074                 return iter->w.leaf;
2075         } else if (r < 0) {
2076                 fib6_walker_unlink(net, &iter->w);
2077                 return NULL;
2078         }
2079         fib6_walker_unlink(net, &iter->w);
2080
2081         iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
2082         if (!iter->tbl)
2083                 return NULL;
2084
2085         ipv6_route_seq_setup_walk(iter, net);
2086         goto iter_table;
2087 }
2088
2089 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
2090         __acquires(RCU_BH)
2091 {
2092         struct net *net = seq_file_net(seq);
2093         struct ipv6_route_iter *iter = seq->private;
2094
2095         rcu_read_lock_bh();
2096         iter->tbl = ipv6_route_seq_next_table(NULL, net);
2097         iter->skip = *pos;
2098
2099         if (iter->tbl) {
2100                 ipv6_route_seq_setup_walk(iter, net);
2101                 return ipv6_route_seq_next(seq, NULL, pos);
2102         } else {
2103                 return NULL;
2104         }
2105 }
2106
2107 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
2108 {
2109         struct fib6_walker *w = &iter->w;
2110         return w->node && !(w->state == FWS_U && w->node == w->root);
2111 }
2112
2113 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2114         __releases(RCU_BH)
2115 {
2116         struct net *net = seq_file_net(seq);
2117         struct ipv6_route_iter *iter = seq->private;
2118
2119         if (ipv6_route_iter_active(iter))
2120                 fib6_walker_unlink(net, &iter->w);
2121
2122         rcu_read_unlock_bh();
2123 }
2124
2125 static const struct seq_operations ipv6_route_seq_ops = {
2126         .start  = ipv6_route_seq_start,
2127         .next   = ipv6_route_seq_next,
2128         .stop   = ipv6_route_seq_stop,
2129         .show   = ipv6_route_seq_show
2130 };
2131
2132 int ipv6_route_open(struct inode *inode, struct file *file)
2133 {
2134         return seq_open_net(inode, file, &ipv6_route_seq_ops,
2135                             sizeof(struct ipv6_route_iter));
2136 }
2137
2138 #endif /* CONFIG_PROC_FS */