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
  14 /*
  15  *      Changes:
  16  *      Yuji SEKIYA @USAGI:     Support default route on router node;
  17  *                              remove ip6_null_entry from the top of
  18  *                              routing table.
  19  *      Ville Nuorvala:         Fixed routing subtrees.
  20  */
  21
  22 #define pr_fmt(fmt) "IPv6: " fmt
  23
  24 #include <linux/errno.h>
  25 #include <linux/types.h>
  26 #include <linux/net.h>
  27 #include <linux/route.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/in6.h>
  30 #include <linux/init.h>
  31 #include <linux/list.h>
  32 #include <linux/slab.h>
  33
  34 #include <net/ipv6.h>
  35 #include <net/ndisc.h>
  36 #include <net/addrconf.h>
  37
  38 #include <net/ip6_fib.h>
  39 #include <net/ip6_route.h>
  40
  41 #define RT6_DEBUG 2
  42
  43 #if RT6_DEBUG >= 3
  44 #define RT6_TRACE(x...) pr_debug(x)
  45 #else
  46 #define RT6_TRACE(x...) do { ; } while (0)
  47 #endif
  48
  49 static struct kmem_cache * fib6_node_kmem __read_mostly;
  50
  51 enum fib_walk_state_t
  52 {
  53 #ifdef CONFIG_IPV6_SUBTREES
  54         FWS_S,
  55 #endif
  56         FWS_L,
  57         FWS_R,
  58         FWS_C,
  59         FWS_U
  60 };
  61
  62 struct fib6_cleaner_t
  63 {
  64         struct fib6_walker_t w;
  65         struct net *net;
  66         int (*func)(struct rt6_info *, void *arg);
  67         void *arg;
  68 };
  69
  70 static DEFINE_RWLOCK(fib6_walker_lock);
  71
  72 #ifdef CONFIG_IPV6_SUBTREES
  73 #define FWS_INIT FWS_S
  74 #else
  75 #define FWS_INIT FWS_L
  76 #endif
  77
  78 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
  79                               struct rt6_info *rt);
  80 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
  81 static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
  82 static int fib6_walk(struct fib6_walker_t *w);
  83 static int fib6_walk_continue(struct fib6_walker_t *w);
  84
  85 /*
  86  *      A routing update causes an increase of the serial number on the
  87  *      affected subtree. This allows for cached routes to be asynchronously
  88  *      tested when modifications are made to the destination cache as a
  89  *      result of redirects, path MTU changes, etc.
  90  */
  91
  92 static __u32 rt_sernum;
  93
  94 static void fib6_gc_timer_cb(unsigned long arg);
  95
  96 static LIST_HEAD(fib6_walkers);
  97 #define FOR_WALKERS(w) list_for_each_entry(w, &fib6_walkers, lh)
  98
  99 static inline void fib6_walker_link(struct fib6_walker_t *w)
 100 {
 101         write_lock_bh(&fib6_walker_lock);
 102         list_add(&w->lh, &fib6_walkers);
 103         write_unlock_bh(&fib6_walker_lock);
 104 }
 105
 106 static inline void fib6_walker_unlink(struct fib6_walker_t *w)
 107 {
 108         write_lock_bh(&fib6_walker_lock);
 109         list_del(&w->lh);
 110         write_unlock_bh(&fib6_walker_lock);
 111 }
 112 static __inline__ u32 fib6_new_sernum(void)
 113 {
 114         u32 n = ++rt_sernum;
 115         if ((__s32)n <= 0)
 116                 rt_sernum = n = 1;
 117         return n;
 118 }
 119
 120 /*
 121  *      Auxiliary address test functions for the radix tree.
 122  *
 123  *      These assume a 32bit processor (although it will work on
 124  *      64bit processors)
 125  */
 126
 127 /*
 128  *      test bit
 129  */
 130 #if defined(__LITTLE_ENDIAN)
 131 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
 132 #else
 133 # define BITOP_BE32_SWIZZLE     0
 134 #endif
 135
 136 static __inline__ __be32 addr_bit_set(const void *token, int fn_bit)
 137 {
 138         const __be32 *addr = token;
 139         /*
 140          * Here,
 141          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
 142          * is optimized version of
 143          *      htonl(1 << ((~fn_bit)&0x1F))
 144          * See include/asm-generic/bitops/le.h.
 145          */
 146         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
 147                addr[fn_bit >> 5];
 148 }
 149
 150 static __inline__ struct fib6_node * node_alloc(void)
 151 {
 152         struct fib6_node *fn;
 153
 154         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 155
 156         return fn;
 157 }
 158
 159 static __inline__ void node_free(struct fib6_node * fn)
 160 {
 161         kmem_cache_free(fib6_node_kmem, fn);
 162 }
 163
 164 static __inline__ void rt6_release(struct rt6_info *rt)
 165 {
 166         if (atomic_dec_and_test(&rt->rt6i_ref))
 167                 dst_free(&rt->dst);
 168 }
 169
 170 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 171 {
 172         unsigned int h;
 173
 174         /*
 175          * Initialize table lock at a single place to give lockdep a key,
 176          * tables aren't visible prior to being linked to the list.
 177          */
 178         rwlock_init(&tb->tb6_lock);
 179
 180         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 181
 182         /*
 183          * No protection necessary, this is the only list mutatation
 184          * operation, tables never disappear once they exist.
 185          */
 186         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 187 }
 188
 189 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 190
 191 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 192 {
 193         struct fib6_table *table;
 194
 195         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 196         if (table) {
 197                 table->tb6_id = id;
 198                 table->tb6_root.leaf = net->ipv6.ip6_null_entry;
 199                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 200                 inet_peer_base_init(&table->tb6_peers);
 201         }
 202
 203         return table;
 204 }
 205
 206 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 207 {
 208         struct fib6_table *tb;
 209
 210         if (id == 0)
 211                 id = RT6_TABLE_MAIN;
 212         tb = fib6_get_table(net, id);
 213         if (tb)
 214                 return tb;
 215
 216         tb = fib6_alloc_table(net, id);
 217         if (tb)
 218                 fib6_link_table(net, tb);
 219
 220         return tb;
 221 }
 222
 223 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 224 {
 225         struct fib6_table *tb;
 226         struct hlist_head *head;
 227         unsigned int h;
 228
 229         if (id == 0)
 230                 id = RT6_TABLE_MAIN;
 231         h = id & (FIB6_TABLE_HASHSZ - 1);
 232         rcu_read_lock();
 233         head = &net->ipv6.fib_table_hash[h];
 234         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 235                 if (tb->tb6_id == id) {
 236                         rcu_read_unlock();
 237                         return tb;
 238                 }
 239         }
 240         rcu_read_unlock();
 241
 242         return NULL;
 243 }
 244
 245 static void __net_init fib6_tables_init(struct net *net)
 246 {
 247         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 248         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 249 }
 250 #else
 251
 252 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 253 {
 254         return fib6_get_table(net, id);
 255 }
 256
 257 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 258 {
 259           return net->ipv6.fib6_main_tbl;
 260 }
 261
 262 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 263                                    int flags, pol_lookup_t lookup)
 264 {
 265         return (struct dst_entry *) lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
 266 }
 267
 268 static void __net_init fib6_tables_init(struct net *net)
 269 {
 270         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 271 }
 272
 273 #endif
 274
 275 static int fib6_dump_node(struct fib6_walker_t *w)
 276 {
 277         int res;
 278         struct rt6_info *rt;
 279
 280         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
 281                 res = rt6_dump_route(rt, w->args);
 282                 if (res < 0) {
 283                         /* Frame is full, suspend walking */
 284                         w->leaf = rt;
 285                         return 1;
 286                 }
 287                 WARN_ON(res == 0);
 288         }
 289         w->leaf = NULL;
 290         return 0;
 291 }
 292
 293 static void fib6_dump_end(struct netlink_callback *cb)
 294 {
 295         struct fib6_walker_t *w = (void*)cb->args[2];
 296
 297         if (w) {
 298                 if (cb->args[4]) {
 299                         cb->args[4] = 0;
 300                         fib6_walker_unlink(w);
 301                 }
 302                 cb->args[2] = 0;
 303                 kfree(w);
 304         }
 305         cb->done = (void*)cb->args[3];
 306         cb->args[1] = 3;
 307 }
 308
 309 static int fib6_dump_done(struct netlink_callback *cb)
 310 {
 311         fib6_dump_end(cb);
 312         return cb->done ? cb->done(cb) : 0;
 313 }
 314
 315 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 316                            struct netlink_callback *cb)
 317 {
 318         struct fib6_walker_t *w;
 319         int res;
 320
 321         w = (void *)cb->args[2];
 322         w->root = &table->tb6_root;
 323
 324         if (cb->args[4] == 0) {
 325                 w->count = 0;
 326                 w->skip = 0;
 327
 328                 read_lock_bh(&table->tb6_lock);
 329                 res = fib6_walk(w);
 330                 read_unlock_bh(&table->tb6_lock);
 331                 if (res > 0) {
 332                         cb->args[4] = 1;
 333                         cb->args[5] = w->root->fn_sernum;
 334                 }
 335         } else {
 336                 if (cb->args[5] != w->root->fn_sernum) {
 337                         /* Begin at the root if the tree changed */
 338                         cb->args[5] = w->root->fn_sernum;
 339                         w->state = FWS_INIT;
 340                         w->node = w->root;
 341                         w->skip = w->count;
 342                 } else
 343                         w->skip = 0;
 344
 345                 read_lock_bh(&table->tb6_lock);
 346                 res = fib6_walk_continue(w);
 347                 read_unlock_bh(&table->tb6_lock);
 348                 if (res <= 0) {
 349                         fib6_walker_unlink(w);
 350                         cb->args[4] = 0;
 351                 }
 352         }
 353
 354         return res;
 355 }
 356
 357 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 358 {
 359         struct net *net = sock_net(skb->sk);
 360         unsigned int h, s_h;
 361         unsigned int e = 0, s_e;
 362         struct rt6_rtnl_dump_arg arg;
 363         struct fib6_walker_t *w;
 364         struct fib6_table *tb;
 365         struct hlist_head *head;
 366         int res = 0;
 367
 368         s_h = cb->args[0];
 369         s_e = cb->args[1];
 370
 371         w = (void *)cb->args[2];
 372         if (!w) {
 373                 /* New dump:
 374                  *
 375                  * 1. hook callback destructor.
 376                  */
 377                 cb->args[3] = (long)cb->done;
 378                 cb->done = fib6_dump_done;
 379
 380                 /*
 381                  * 2. allocate and initialize walker.
 382                  */
 383                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 384                 if (!w)
 385                         return -ENOMEM;
 386                 w->func = fib6_dump_node;
 387                 cb->args[2] = (long)w;
 388         }
 389
 390         arg.skb = skb;
 391         arg.cb = cb;
 392         arg.net = net;
 393         w->args = &arg;
 394
 395         rcu_read_lock();
 396         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 397                 e = 0;
 398                 head = &net->ipv6.fib_table_hash[h];
 399                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 400                         if (e < s_e)
 401                                 goto next;
 402                         res = fib6_dump_table(tb, skb, cb);
 403                         if (res != 0)
 404                                 goto out;
 405 next:
 406                         e++;
 407                 }
 408         }
 409 out:
 410         rcu_read_unlock();
 411         cb->args[1] = e;
 412         cb->args[0] = h;
 413
 414         res = res < 0 ? res : skb->len;
 415         if (res <= 0)
 416                 fib6_dump_end(cb);
 417         return res;
 418 }
 419
 420 /*
 421  *      Routing Table
 422  *
 423  *      return the appropriate node for a routing tree "add" operation
 424  *      by either creating and inserting or by returning an existing
 425  *      node.
 426  */
 427
 428 static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
 429                                      int addrlen, int plen,
 430                                      int offset, int allow_create,
 431                                      int replace_required)
 432 {
 433         struct fib6_node *fn, *in, *ln;
 434         struct fib6_node *pn = NULL;
 435         struct rt6key *key;
 436         int     bit;
 437         __be32  dir = 0;
 438         __u32   sernum = fib6_new_sernum();
 439
 440         RT6_TRACE("fib6_add_1\n");
 441
 442         /* insert node in tree */
 443
 444         fn = root;
 445
 446         do {
 447                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
 448
 449                 /*
 450                  *      Prefix match
 451                  */
 452                 if (plen < fn->fn_bit ||
 453                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 454                         if (!allow_create) {
 455                                 if (replace_required) {
 456                                         pr_warn("Can't replace route, no match found\n");
 457                                         return ERR_PTR(-ENOENT);
 458                                 }
 459                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 460                         }
 461                         goto insert_above;
 462                 }
 463
 464                 /*
 465                  *      Exact match ?
 466                  */
 467
 468                 if (plen == fn->fn_bit) {
 469                         /* clean up an intermediate node */
 470                         if (!(fn->fn_flags & RTN_RTINFO)) {
 471                                 rt6_release(fn->leaf);
 472                                 fn->leaf = NULL;
 473                         }
 474
 475                         fn->fn_sernum = sernum;
 476
 477                         return fn;
 478                 }
 479
 480                 /*
 481                  *      We have more bits to go
 482                  */
 483
 484                 /* Try to walk down on tree. */
 485                 fn->fn_sernum = sernum;
 486                 dir = addr_bit_set(addr, fn->fn_bit);
 487                 pn = fn;
 488                 fn = dir ? fn->right: fn->left;
 489         } while (fn);
 490
 491         if (!allow_create) {
 492                 /* We should not create new node because
 493                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 494                  * I assume it is safe to require NLM_F_CREATE when
 495                  * REPLACE flag is used! Later we may want to remove the
 496                  * check for replace_required, because according
 497                  * to netlink specification, NLM_F_CREATE
 498                  * MUST be specified if new route is created.
 499                  * That would keep IPv6 consistent with IPv4
 500                  */
 501                 if (replace_required) {
 502                         pr_warn("Can't replace route, no match found\n");
 503                         return ERR_PTR(-ENOENT);
 504                 }
 505                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 506         }
 507         /*
 508          *      We walked to the bottom of tree.
 509          *      Create new leaf node without children.
 510          */
 511
 512         ln = node_alloc();
 513
 514         if (!ln)
 515                 return ERR_PTR(-ENOMEM);
 516         ln->fn_bit = plen;
 517
 518         ln->parent = pn;
 519         ln->fn_sernum = sernum;
 520
 521         if (dir)
 522                 pn->right = ln;
 523         else
 524                 pn->left  = ln;
 525
 526         return ln;
 527
 528
 529 insert_above:
 530         /*
 531          * split since we don't have a common prefix anymore or
 532          * we have a less significant route.
 533          * we've to insert an intermediate node on the list
 534          * this new node will point to the one we need to create
 535          * and the current
 536          */
 537
 538         pn = fn->parent;
 539
 540         /* find 1st bit in difference between the 2 addrs.
 541
 542            See comment in __ipv6_addr_diff: bit may be an invalid value,
 543            but if it is >= plen, the value is ignored in any case.
 544          */
 545
 546         bit = __ipv6_addr_diff(addr, &key->addr, addrlen);
 547
 548         /*
 549          *              (intermediate)[in]
 550          *                /        \
 551          *      (new leaf node)[ln] (old node)[fn]
 552          */
 553         if (plen > bit) {
 554                 in = node_alloc();
 555                 ln = node_alloc();
 556
 557                 if (!in || !ln) {
 558                         if (in)
 559                                 node_free(in);
 560                         if (ln)
 561                                 node_free(ln);
 562                         return ERR_PTR(-ENOMEM);
 563                 }
 564
 565                 /*
 566                  * new intermediate node.
 567                  * RTN_RTINFO will
 568                  * be off since that an address that chooses one of
 569                  * the branches would not match less specific routes
 570                  * in the other branch
 571                  */
 572
 573                 in->fn_bit = bit;
 574
 575                 in->parent = pn;
 576                 in->leaf = fn->leaf;
 577                 atomic_inc(&in->leaf->rt6i_ref);
 578
 579                 in->fn_sernum = sernum;
 580
 581                 /* update parent pointer */
 582                 if (dir)
 583                         pn->right = in;
 584                 else
 585                         pn->left  = in;
 586
 587                 ln->fn_bit = plen;
 588
 589                 ln->parent = in;
 590                 fn->parent = in;
 591
 592                 ln->fn_sernum = sernum;
 593
 594                 if (addr_bit_set(addr, bit)) {
 595                         in->right = ln;
 596                         in->left  = fn;
 597                 } else {
 598                         in->left  = ln;
 599                         in->right = fn;
 600                 }
 601         } else { /* plen <= bit */
 602
 603                 /*
 604                  *              (new leaf node)[ln]
 605                  *                /        \
 606                  *           (old node)[fn] NULL
 607                  */
 608
 609                 ln = node_alloc();
 610
 611                 if (!ln)
 612                         return ERR_PTR(-ENOMEM);
 613
 614                 ln->fn_bit = plen;
 615
 616                 ln->parent = pn;
 617
 618                 ln->fn_sernum = sernum;
 619
 620                 if (dir)
 621                         pn->right = ln;
 622                 else
 623                         pn->left  = ln;
 624
 625                 if (addr_bit_set(&key->addr, plen))
 626                         ln->right = fn;
 627                 else
 628                         ln->left  = fn;
 629
 630                 fn->parent = ln;
 631         }
 632         return ln;
 633 }
 634
 635 /*
 636  *      Insert routing information in a node.
 637  */
 638
 639 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 640                             struct nl_info *info)
 641 {
 642         struct rt6_info *iter = NULL;
 643         struct rt6_info **ins;
 644         int replace = (info->nlh &&
 645                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 646         int add = (!info->nlh ||
 647                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
 648         int found = 0;
 649
 650         ins = &fn->leaf;
 651
 652         for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
 653                 /*
 654                  *      Search for duplicates
 655                  */
 656
 657                 if (iter->rt6i_metric == rt->rt6i_metric) {
 658                         /*
 659                          *      Same priority level
 660                          */
 661                         if (info->nlh &&
 662                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
 663                                 return -EEXIST;
 664                         if (replace) {
 665                                 found++;
 666                                 break;
 667                         }
 668
 669                         if (iter->dst.dev == rt->dst.dev &&
 670                             iter->rt6i_idev == rt->rt6i_idev &&
 671                             ipv6_addr_equal(&iter->rt6i_gateway,
 672                                             &rt->rt6i_gateway)) {
 673                                 if (rt->rt6i_nsiblings)
 674                                         rt->rt6i_nsiblings = 0;
 675                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
 676                                         return -EEXIST;
 677                                 if (!(rt->rt6i_flags & RTF_EXPIRES))
 678                                         rt6_clean_expires(iter);
 679                                 else
 680                                         rt6_set_expires(iter, rt->dst.expires);
 681                                 return -EEXIST;
 682                         }
 683                         /* If we have the same destination and the same metric,
 684                          * but not the same gateway, then the route we try to
 685                          * add is sibling to this route, increment our counter
 686                          * of siblings, and later we will add our route to the
 687                          * list.
 688                          * Only static routes (which don't have flag
 689                          * RTF_EXPIRES) are used for ECMPv6.
 690                          *
 691                          * To avoid long list, we only had siblings if the
 692                          * route have a gateway.
 693                          */
 694                         if (rt->rt6i_flags & RTF_GATEWAY &&
 695                             !(rt->rt6i_flags & RTF_EXPIRES) &&
 696                             !(iter->rt6i_flags & RTF_EXPIRES))
 697                                 rt->rt6i_nsiblings++;
 698                 }
 699
 700                 if (iter->rt6i_metric > rt->rt6i_metric)
 701                         break;
 702
 703                 ins = &iter->dst.rt6_next;
 704         }
 705
 706         /* Reset round-robin state, if necessary */
 707         if (ins == &fn->leaf)
 708                 fn->rr_ptr = NULL;
 709
 710         /* Link this route to others same route. */
 711         if (rt->rt6i_nsiblings) {
 712                 unsigned int rt6i_nsiblings;
 713                 struct rt6_info *sibling, *temp_sibling;
 714
 715                 /* Find the first route that have the same metric */
 716                 sibling = fn->leaf;
 717                 while (sibling) {
 718                         if (sibling->rt6i_metric == rt->rt6i_metric) {
 719                                 list_add_tail(&rt->rt6i_siblings,
 720                                               &sibling->rt6i_siblings);
 721                                 break;
 722                         }
 723                         sibling = sibling->dst.rt6_next;
 724                 }
 725                 /* For each sibling in the list, increment the counter of
 726                  * siblings. BUG() if counters does not match, list of siblings
 727                  * is broken!
 728                  */
 729                 rt6i_nsiblings = 0;
 730                 list_for_each_entry_safe(sibling, temp_sibling,
 731                                          &rt->rt6i_siblings, rt6i_siblings) {
 732                         sibling->rt6i_nsiblings++;
 733                         BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
 734                         rt6i_nsiblings++;
 735                 }
 736                 BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
 737         }
 738
 739         /*
 740          *      insert node
 741          */
 742         if (!replace) {
 743                 if (!add)
 744                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
 745
 746 add:
 747                 rt->dst.rt6_next = iter;
 748                 *ins = rt;
 749                 rt->rt6i_node = fn;
 750                 atomic_inc(&rt->rt6i_ref);
 751                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 752                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 753
 754                 if (!(fn->fn_flags & RTN_RTINFO)) {
 755                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 756                         fn->fn_flags |= RTN_RTINFO;
 757                 }
 758
 759         } else {
 760                 if (!found) {
 761                         if (add)
 762                                 goto add;
 763                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
 764                         return -ENOENT;
 765                 }
 766                 *ins = rt;
 767                 rt->rt6i_node = fn;
 768                 rt->dst.rt6_next = iter->dst.rt6_next;
 769                 atomic_inc(&rt->rt6i_ref);
 770                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 771                 rt6_release(iter);
 772                 if (!(fn->fn_flags & RTN_RTINFO)) {
 773                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 774                         fn->fn_flags |= RTN_RTINFO;
 775                 }
 776         }
 777
 778         return 0;
 779 }
 780
 781 static __inline__ void fib6_start_gc(struct net *net, struct rt6_info *rt)
 782 {
 783         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 784             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 785                 mod_timer(&net->ipv6.ip6_fib_timer,
 786                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 787 }
 788
 789 void fib6_force_start_gc(struct net *net)
 790 {
 791         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 792                 mod_timer(&net->ipv6.ip6_fib_timer,
 793                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 794 }
 795
 796 /*
 797  *      Add routing information to the routing tree.
 798  *      <destination addr>/<source addr>
 799  *      with source addr info in sub-trees
 800  */
 801
 802 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
 803 {
 804         struct fib6_node *fn, *pn = NULL;
 805         int err = -ENOMEM;
 806         int allow_create = 1;
 807         int replace_required = 0;
 808
 809         if (info->nlh) {
 810                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 811                         allow_create = 0;
 812                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 813                         replace_required = 1;
 814         }
 815         if (!allow_create && !replace_required)
 816                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 817
 818         fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
 819                         rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst),
 820                         allow_create, replace_required);
 821
 822         if (IS_ERR(fn)) {
 823                 err = PTR_ERR(fn);
 824                 goto out;
 825         }
 826
 827         pn = fn;
 828
 829 #ifdef CONFIG_IPV6_SUBTREES
 830         if (rt->rt6i_src.plen) {
 831                 struct fib6_node *sn;
 832
 833                 if (!fn->subtree) {
 834                         struct fib6_node *sfn;
 835
 836                         /*
 837                          * Create subtree.
 838                          *
 839                          *              fn[main tree]
 840                          *              |
 841                          *              sfn[subtree root]
 842                          *                 \
 843                          *                  sn[new leaf node]
 844                          */
 845
 846                         /* Create subtree root node */
 847                         sfn = node_alloc();
 848                         if (!sfn)
 849                                 goto st_failure;
 850
 851                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 852                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 853                         sfn->fn_flags = RTN_ROOT;
 854                         sfn->fn_sernum = fib6_new_sernum();
 855
 856                         /* Now add the first leaf node to new subtree */
 857
 858                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 859                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 860                                         offsetof(struct rt6_info, rt6i_src),
 861                                         allow_create, replace_required);
 862
 863                         if (IS_ERR(sn)) {
 864                                 /* If it is failed, discard just allocated
 865                                    root, and then (in st_failure) stale node
 866                                    in main tree.
 867                                  */
 868                                 node_free(sfn);
 869                                 err = PTR_ERR(sn);
 870                                 goto st_failure;
 871                         }
 872
 873                         /* Now link new subtree to main tree */
 874                         sfn->parent = fn;
 875                         fn->subtree = sfn;
 876                 } else {
 877                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 878                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 879                                         offsetof(struct rt6_info, rt6i_src),
 880                                         allow_create, replace_required);
 881
 882                         if (IS_ERR(sn)) {
 883                                 err = PTR_ERR(sn);
 884                                 goto st_failure;
 885                         }
 886                 }
 887
 888                 if (!fn->leaf) {
 889                         fn->leaf = rt;
 890                         atomic_inc(&rt->rt6i_ref);
 891                 }
 892                 fn = sn;
 893         }
 894 #endif
 895
 896         err = fib6_add_rt2node(fn, rt, info);
 897         if (!err) {
 898                 fib6_start_gc(info->nl_net, rt);
 899                 if (!(rt->rt6i_flags & RTF_CACHE))
 900                         fib6_prune_clones(info->nl_net, pn, rt);
 901         }
 902
 903 out:
 904         if (err) {
 905 #ifdef CONFIG_IPV6_SUBTREES
 906                 /*
 907                  * If fib6_add_1 has cleared the old leaf pointer in the
 908                  * super-tree leaf node we have to find a new one for it.
 909                  */
 910                 if (pn != fn && pn->leaf == rt) {
 911                         pn->leaf = NULL;
 912                         atomic_dec(&rt->rt6i_ref);
 913                 }
 914                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 915                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
 916 #if RT6_DEBUG >= 2
 917                         if (!pn->leaf) {
 918                                 WARN_ON(pn->leaf == NULL);
 919                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 920                         }
 921 #endif
 922                         atomic_inc(&pn->leaf->rt6i_ref);
 923                 }
 924 #endif
 925                 dst_free(&rt->dst);
 926         }
 927         return err;
 928
 929 #ifdef CONFIG_IPV6_SUBTREES
 930         /* Subtree creation failed, probably main tree node
 931            is orphan. If it is, shoot it.
 932          */
 933 st_failure:
 934         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 935                 fib6_repair_tree(info->nl_net, fn);
 936         dst_free(&rt->dst);
 937         return err;
 938 #endif
 939 }
 940
 941 /*
 942  *      Routing tree lookup
 943  *
 944  */
 945
 946 struct lookup_args {
 947         int                     offset;         /* key offset on rt6_info       */
 948         const struct in6_addr   *addr;          /* search key                   */
 949 };
 950
 951 static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 952                                         struct lookup_args *args)
 953 {
 954         struct fib6_node *fn;
 955         __be32 dir;
 956
 957         if (unlikely(args->offset == 0))
 958                 return NULL;
 959
 960         /*
 961          *      Descend on a tree
 962          */
 963
 964         fn = root;
 965
 966         for (;;) {
 967                 struct fib6_node *next;
 968
 969                 dir = addr_bit_set(args->addr, fn->fn_bit);
 970
 971                 next = dir ? fn->right : fn->left;
 972
 973                 if (next) {
 974                         fn = next;
 975                         continue;
 976                 }
 977                 break;
 978         }
 979
 980         while (fn) {
 981                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
 982                         struct rt6key *key;
 983
 984                         key = (struct rt6key *) ((u8 *) fn->leaf +
 985                                                  args->offset);
 986
 987                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 988 #ifdef CONFIG_IPV6_SUBTREES
 989                                 if (fn->subtree)
 990                                         fn = fib6_lookup_1(fn->subtree, args + 1);
 991 #endif
 992                                 if (!fn || fn->fn_flags & RTN_RTINFO)
 993                                         return fn;
 994                         }
 995                 }
 996
 997                 if (fn->fn_flags & RTN_ROOT)
 998                         break;
 999
1000                 fn = fn->parent;
1001         }
1002
1003         return NULL;
1004 }
1005
1006 struct fib6_node * fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
1007                                const struct in6_addr *saddr)
1008 {
1009         struct fib6_node *fn;
1010         struct lookup_args args[] = {
1011                 {
1012                         .offset = offsetof(struct rt6_info, rt6i_dst),
1013                         .addr = daddr,
1014                 },
1015 #ifdef CONFIG_IPV6_SUBTREES
1016                 {
1017                         .offset = offsetof(struct rt6_info, rt6i_src),
1018                         .addr = saddr,
1019                 },
1020 #endif
1021                 {
1022                         .offset = 0,    /* sentinel */
1023                 }
1024         };
1025
1026         fn = fib6_lookup_1(root, daddr ? args : args + 1);
1027         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1028                 fn = root;
1029
1030         return fn;
1031 }
1032
1033 /*
1034  *      Get node with specified destination prefix (and source prefix,
1035  *      if subtrees are used)
1036  */
1037
1038
1039 static struct fib6_node * fib6_locate_1(struct fib6_node *root,
1040                                         const struct in6_addr *addr,
1041                                         int plen, int offset)
1042 {
1043         struct fib6_node *fn;
1044
1045         for (fn = root; fn ; ) {
1046                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1047
1048                 /*
1049                  *      Prefix match
1050                  */
1051                 if (plen < fn->fn_bit ||
1052                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1053                         return NULL;
1054
1055                 if (plen == fn->fn_bit)
1056                         return fn;
1057
1058                 /*
1059                  *      We have more bits to go
1060                  */
1061                 if (addr_bit_set(addr, fn->fn_bit))
1062                         fn = fn->right;
1063                 else
1064                         fn = fn->left;
1065         }
1066         return NULL;
1067 }
1068
1069 struct fib6_node * fib6_locate(struct fib6_node *root,
1070                                const struct in6_addr *daddr, int dst_len,
1071                                const struct in6_addr *saddr, int src_len)
1072 {
1073         struct fib6_node *fn;
1074
1075         fn = fib6_locate_1(root, daddr, dst_len,
1076                            offsetof(struct rt6_info, rt6i_dst));
1077
1078 #ifdef CONFIG_IPV6_SUBTREES
1079         if (src_len) {
1080                 WARN_ON(saddr == NULL);
1081                 if (fn && fn->subtree)
1082                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
1083                                            offsetof(struct rt6_info, rt6i_src));
1084         }
1085 #endif
1086
1087         if (fn && fn->fn_flags & RTN_RTINFO)
1088                 return fn;
1089
1090         return NULL;
1091 }
1092
1093
1094 /*
1095  *      Deletion
1096  *
1097  */
1098
1099 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1100 {
1101         if (fn->fn_flags & RTN_ROOT)
1102                 return net->ipv6.ip6_null_entry;
1103
1104         while (fn) {
1105                 if (fn->left)
1106                         return fn->left->leaf;
1107                 if (fn->right)
1108                         return fn->right->leaf;
1109
1110                 fn = FIB6_SUBTREE(fn);
1111         }
1112         return NULL;
1113 }
1114
1115 /*
1116  *      Called to trim the tree of intermediate nodes when possible. "fn"
1117  *      is the node we want to try and remove.
1118  */
1119
1120 static struct fib6_node *fib6_repair_tree(struct net *net,
1121                                            struct fib6_node *fn)
1122 {
1123         int children;
1124         int nstate;
1125         struct fib6_node *child, *pn;
1126         struct fib6_walker_t *w;
1127         int iter = 0;
1128
1129         for (;;) {
1130                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1131                 iter++;
1132
1133                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1134                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1135                 WARN_ON(fn->leaf != NULL);
1136
1137                 children = 0;
1138                 child = NULL;
1139                 if (fn->right) child = fn->right, children |= 1;
1140                 if (fn->left) child = fn->left, children |= 2;
1141
1142                 if (children == 3 || FIB6_SUBTREE(fn)
1143 #ifdef CONFIG_IPV6_SUBTREES
1144                     /* Subtree root (i.e. fn) may have one child */
1145                     || (children && fn->fn_flags & RTN_ROOT)
1146 #endif
1147                     ) {
1148                         fn->leaf = fib6_find_prefix(net, fn);
1149 #if RT6_DEBUG >= 2
1150                         if (!fn->leaf) {
1151                                 WARN_ON(!fn->leaf);
1152                                 fn->leaf = net->ipv6.ip6_null_entry;
1153                         }
1154 #endif
1155                         atomic_inc(&fn->leaf->rt6i_ref);
1156                         return fn->parent;
1157                 }
1158
1159                 pn = fn->parent;
1160 #ifdef CONFIG_IPV6_SUBTREES
1161                 if (FIB6_SUBTREE(pn) == fn) {
1162                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1163                         FIB6_SUBTREE(pn) = NULL;
1164                         nstate = FWS_L;
1165                 } else {
1166                         WARN_ON(fn->fn_flags & RTN_ROOT);
1167 #endif
1168                         if (pn->right == fn) pn->right = child;
1169                         else if (pn->left == fn) pn->left = child;
1170 #if RT6_DEBUG >= 2
1171                         else
1172                                 WARN_ON(1);
1173 #endif
1174                         if (child)
1175                                 child->parent = pn;
1176                         nstate = FWS_R;
1177 #ifdef CONFIG_IPV6_SUBTREES
1178                 }
1179 #endif
1180
1181                 read_lock(&fib6_walker_lock);
1182                 FOR_WALKERS(w) {
1183                         if (!child) {
1184                                 if (w->root == fn) {
1185                                         w->root = w->node = NULL;
1186                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1187                                 } else if (w->node == fn) {
1188                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1189                                         w->node = pn;
1190                                         w->state = nstate;
1191                                 }
1192                         } else {
1193                                 if (w->root == fn) {
1194                                         w->root = child;
1195                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1196                                 }
1197                                 if (w->node == fn) {
1198                                         w->node = child;
1199                                         if (children&2) {
1200                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1201                                                 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1202                                         } else {
1203                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1204                                                 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1205                                         }
1206                                 }
1207                         }
1208                 }
1209                 read_unlock(&fib6_walker_lock);
1210
1211                 node_free(fn);
1212                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1213                         return pn;
1214
1215                 rt6_release(pn->leaf);
1216                 pn->leaf = NULL;
1217                 fn = pn;
1218         }
1219 }
1220
1221 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1222                            struct nl_info *info)
1223 {
1224         struct fib6_walker_t *w;
1225         struct rt6_info *rt = *rtp;
1226         struct net *net = info->nl_net;
1227
1228         RT6_TRACE("fib6_del_route\n");
1229
1230         /* Unlink it */
1231         *rtp = rt->dst.rt6_next;
1232         rt->rt6i_node = NULL;
1233         net->ipv6.rt6_stats->fib_rt_entries--;
1234         net->ipv6.rt6_stats->fib_discarded_routes++;
1235
1236         /* Reset round-robin state, if necessary */
1237         if (fn->rr_ptr == rt)
1238                 fn->rr_ptr = NULL;
1239
1240         /* Remove this entry from other siblings */
1241         if (rt->rt6i_nsiblings) {
1242                 struct rt6_info *sibling, *next_sibling;
1243
1244                 list_for_each_entry_safe(sibling, next_sibling,
1245                                          &rt->rt6i_siblings, rt6i_siblings)
1246                         sibling->rt6i_nsiblings--;
1247                 rt->rt6i_nsiblings = 0;
1248                 list_del_init(&rt->rt6i_siblings);
1249         }
1250
1251         /* Adjust walkers */
1252         read_lock(&fib6_walker_lock);
1253         FOR_WALKERS(w) {
1254                 if (w->state == FWS_C && w->leaf == rt) {
1255                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1256                         w->leaf = rt->dst.rt6_next;
1257                         if (!w->leaf)
1258                                 w->state = FWS_U;
1259                 }
1260         }
1261         read_unlock(&fib6_walker_lock);
1262
1263         rt->dst.rt6_next = NULL;
1264
1265         /* If it was last route, expunge its radix tree node */
1266         if (!fn->leaf) {
1267                 fn->fn_flags &= ~RTN_RTINFO;
1268                 net->ipv6.rt6_stats->fib_route_nodes--;
1269                 fn = fib6_repair_tree(net, fn);
1270         }
1271
1272         if (atomic_read(&rt->rt6i_ref) != 1) {
1273                 /* This route is used as dummy address holder in some split
1274                  * nodes. It is not leaked, but it still holds other resources,
1275                  * which must be released in time. So, scan ascendant nodes
1276                  * and replace dummy references to this route with references
1277                  * to still alive ones.
1278                  */
1279                 while (fn) {
1280                         if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
1281                                 fn->leaf = fib6_find_prefix(net, fn);
1282                                 atomic_inc(&fn->leaf->rt6i_ref);
1283                                 rt6_release(rt);
1284                         }
1285                         fn = fn->parent;
1286                 }
1287                 /* No more references are possible at this point. */
1288                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1289         }
1290
1291         inet6_rt_notify(RTM_DELROUTE, rt, info);
1292         rt6_release(rt);
1293 }
1294
1295 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1296 {
1297         struct net *net = info->nl_net;
1298         struct fib6_node *fn = rt->rt6i_node;
1299         struct rt6_info **rtp;
1300
1301 #if RT6_DEBUG >= 2
1302         if (rt->dst.obsolete>0) {
1303                 WARN_ON(fn != NULL);
1304                 return -ENOENT;
1305         }
1306 #endif
1307         if (!fn || rt == net->ipv6.ip6_null_entry)
1308                 return -ENOENT;
1309
1310         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1311
1312         if (!(rt->rt6i_flags & RTF_CACHE)) {
1313                 struct fib6_node *pn = fn;
1314 #ifdef CONFIG_IPV6_SUBTREES
1315                 /* clones of this route might be in another subtree */
1316                 if (rt->rt6i_src.plen) {
1317                         while (!(pn->fn_flags & RTN_ROOT))
1318                                 pn = pn->parent;
1319                         pn = pn->parent;
1320                 }
1321 #endif
1322                 fib6_prune_clones(info->nl_net, pn, rt);
1323         }
1324
1325         /*
1326          *      Walk the leaf entries looking for ourself
1327          */
1328
1329         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1330                 if (*rtp == rt) {
1331                         fib6_del_route(fn, rtp, info);
1332                         return 0;
1333                 }
1334         }
1335         return -ENOENT;
1336 }
1337
1338 /*
1339  *      Tree traversal function.
1340  *
1341  *      Certainly, it is not interrupt safe.
1342  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1343  *      It means, that we can modify tree during walking
1344  *      and use this function for garbage collection, clone pruning,
1345  *      cleaning tree when a device goes down etc. etc.
1346  *
1347  *      It guarantees that every node will be traversed,
1348  *      and that it will be traversed only once.
1349  *
1350  *      Callback function w->func may return:
1351  *      0 -> continue walking.
1352  *      positive value -> walking is suspended (used by tree dumps,
1353  *      and probably by gc, if it will be split to several slices)
1354  *      negative value -> terminate walking.
1355  *
1356  *      The function itself returns:
1357  *      0   -> walk is complete.
1358  *      >0  -> walk is incomplete (i.e. suspended)
1359  *      <0  -> walk is terminated by an error.
1360  */
1361
1362 static int fib6_walk_continue(struct fib6_walker_t *w)
1363 {
1364         struct fib6_node *fn, *pn;
1365
1366         for (;;) {
1367                 fn = w->node;
1368                 if (!fn)
1369                         return 0;
1370
1371                 if (w->prune && fn != w->root &&
1372                     fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1373                         w->state = FWS_C;
1374                         w->leaf = fn->leaf;
1375                 }
1376                 switch (w->state) {
1377 #ifdef CONFIG_IPV6_SUBTREES
1378                 case FWS_S:
1379                         if (FIB6_SUBTREE(fn)) {
1380                                 w->node = FIB6_SUBTREE(fn);
1381                                 continue;
1382                         }
1383                         w->state = FWS_L;
1384 #endif
1385                 case FWS_L:
1386                         if (fn->left) {
1387                                 w->node = fn->left;
1388                                 w->state = FWS_INIT;
1389                                 continue;
1390                         }
1391                         w->state = FWS_R;
1392                 case FWS_R:
1393                         if (fn->right) {
1394                                 w->node = fn->right;
1395                                 w->state = FWS_INIT;
1396                                 continue;
1397                         }
1398                         w->state = FWS_C;
1399                         w->leaf = fn->leaf;
1400                 case FWS_C:
1401                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1402                                 int err;
1403
1404                                 if (w->skip) {
1405                                         w->skip--;
1406                                         continue;
1407                                 }
1408
1409                                 err = w->func(w);
1410                                 if (err)
1411                                         return err;
1412
1413                                 w->count++;
1414                                 continue;
1415                         }
1416                         w->state = FWS_U;
1417                 case FWS_U:
1418                         if (fn == w->root)
1419                                 return 0;
1420                         pn = fn->parent;
1421                         w->node = pn;
1422 #ifdef CONFIG_IPV6_SUBTREES
1423                         if (FIB6_SUBTREE(pn) == fn) {
1424                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1425                                 w->state = FWS_L;
1426                                 continue;
1427                         }
1428 #endif
1429                         if (pn->left == fn) {
1430                                 w->state = FWS_R;
1431                                 continue;
1432                         }
1433                         if (pn->right == fn) {
1434                                 w->state = FWS_C;
1435                                 w->leaf = w->node->leaf;
1436                                 continue;
1437                         }
1438 #if RT6_DEBUG >= 2
1439                         WARN_ON(1);
1440 #endif
1441                 }
1442         }
1443 }
1444
1445 static int fib6_walk(struct fib6_walker_t *w)
1446 {
1447         int res;
1448
1449         w->state = FWS_INIT;
1450         w->node = w->root;
1451
1452         fib6_walker_link(w);
1453         res = fib6_walk_continue(w);
1454         if (res <= 0)
1455                 fib6_walker_unlink(w);
1456         return res;
1457 }
1458
1459 static int fib6_clean_node(struct fib6_walker_t *w)
1460 {
1461         int res;
1462         struct rt6_info *rt;
1463         struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1464         struct nl_info info = {
1465                 .nl_net = c->net,
1466         };
1467
1468         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1469                 res = c->func(rt, c->arg);
1470                 if (res < 0) {
1471                         w->leaf = rt;
1472                         res = fib6_del(rt, &info);
1473                         if (res) {
1474 #if RT6_DEBUG >= 2
1475                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1476                                          __func__, rt, rt->rt6i_node, res);
1477 #endif
1478                                 continue;
1479                         }
1480                         return 0;
1481                 }
1482                 WARN_ON(res != 0);
1483         }
1484         w->leaf = rt;
1485         return 0;
1486 }
1487
1488 /*
1489  *      Convenient frontend to tree walker.
1490  *
1491  *      func is called on each route.
1492  *              It may return -1 -> delete this route.
1493  *                            0  -> continue walking
1494  *
1495  *      prune==1 -> only immediate children of node (certainly,
1496  *      ignoring pure split nodes) will be scanned.
1497  */
1498
1499 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1500                             int (*func)(struct rt6_info *, void *arg),
1501                             int prune, void *arg)
1502 {
1503         struct fib6_cleaner_t c;
1504
1505         c.w.root = root;
1506         c.w.func = fib6_clean_node;
1507         c.w.prune = prune;
1508         c.w.count = 0;
1509         c.w.skip = 0;
1510         c.func = func;
1511         c.arg = arg;
1512         c.net = net;
1513
1514         fib6_walk(&c.w);
1515 }
1516
1517 void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg),
1518                     int prune, void *arg)
1519 {
1520         struct fib6_table *table;
1521         struct hlist_head *head;
1522         unsigned int h;
1523
1524         rcu_read_lock();
1525         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1526                 head = &net->ipv6.fib_table_hash[h];
1527                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1528                         read_lock_bh(&table->tb6_lock);
1529                         fib6_clean_tree(net, &table->tb6_root,
1530                                         func, prune, arg);
1531                         read_unlock_bh(&table->tb6_lock);
1532                 }
1533         }
1534         rcu_read_unlock();
1535 }
1536 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
1537                     int prune, void *arg)
1538 {
1539         struct fib6_table *table;
1540         struct hlist_head *head;
1541         unsigned int h;
1542
1543         rcu_read_lock();
1544         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1545                 head = &net->ipv6.fib_table_hash[h];
1546                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1547                         write_lock_bh(&table->tb6_lock);
1548                         fib6_clean_tree(net, &table->tb6_root,
1549                                         func, prune, arg);
1550                         write_unlock_bh(&table->tb6_lock);
1551                 }
1552         }
1553         rcu_read_unlock();
1554 }
1555
1556 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1557 {
1558         if (rt->rt6i_flags & RTF_CACHE) {
1559                 RT6_TRACE("pruning clone %p\n", rt);
1560                 return -1;
1561         }
1562
1563         return 0;
1564 }
1565
1566 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
1567                               struct rt6_info *rt)
1568 {
1569         fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
1570 }
1571
1572 /*
1573  *      Garbage collection
1574  */
1575
1576 static struct fib6_gc_args
1577 {
1578         int                     timeout;
1579         int                     more;
1580 } gc_args;
1581
1582 static int fib6_age(struct rt6_info *rt, void *arg)
1583 {
1584         unsigned long now = jiffies;
1585
1586         /*
1587          *      check addrconf expiration here.
1588          *      Routes are expired even if they are in use.
1589          *
1590          *      Also age clones. Note, that clones are aged out
1591          *      only if they are not in use now.
1592          */
1593
1594         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1595                 if (time_after(now, rt->dst.expires)) {
1596                         RT6_TRACE("expiring %p\n", rt);
1597                         return -1;
1598                 }
1599                 gc_args.more++;
1600         } else if (rt->rt6i_flags & RTF_CACHE) {
1601                 if (atomic_read(&rt->dst.__refcnt) == 0 &&
1602                     time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1603                         RT6_TRACE("aging clone %p\n", rt);
1604                         return -1;
1605                 } else if (rt->rt6i_flags & RTF_GATEWAY) {
1606                         struct neighbour *neigh;
1607                         __u8 neigh_flags = 0;
1608
1609                         neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1610                         if (neigh) {
1611                                 neigh_flags = neigh->flags;
1612                                 neigh_release(neigh);
1613                         }
1614                         if (!(neigh_flags & NTF_ROUTER)) {
1615                                 RT6_TRACE("purging route %p via non-router but gateway\n",
1616                                           rt);
1617                                 return -1;
1618                         }
1619                 }
1620                 gc_args.more++;
1621         }
1622
1623         return 0;
1624 }
1625
1626 static DEFINE_SPINLOCK(fib6_gc_lock);
1627
1628 void fib6_run_gc(unsigned long expires, struct net *net)
1629 {
1630         if (expires != ~0UL) {
1631                 spin_lock_bh(&fib6_gc_lock);
1632                 gc_args.timeout = expires ? (int)expires :
1633                         net->ipv6.sysctl.ip6_rt_gc_interval;
1634         } else {
1635                 if (!spin_trylock_bh(&fib6_gc_lock)) {
1636                         mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1637                         return;
1638                 }
1639                 gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
1640         }
1641
1642         gc_args.more = icmp6_dst_gc();
1643
1644         fib6_clean_all(net, fib6_age, 0, NULL);
1645
1646         if (gc_args.more)
1647                 mod_timer(&net->ipv6.ip6_fib_timer,
1648                           round_jiffies(jiffies
1649                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1650         else
1651                 del_timer(&net->ipv6.ip6_fib_timer);
1652         spin_unlock_bh(&fib6_gc_lock);
1653 }
1654
1655 static void fib6_gc_timer_cb(unsigned long arg)
1656 {
1657         fib6_run_gc(0, (struct net *)arg);
1658 }
1659
1660 static int __net_init fib6_net_init(struct net *net)
1661 {
1662         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1663
1664         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1665
1666         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1667         if (!net->ipv6.rt6_stats)
1668                 goto out_timer;
1669
1670         /* Avoid false sharing : Use at least a full cache line */
1671         size = max_t(size_t, size, L1_CACHE_BYTES);
1672
1673         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1674         if (!net->ipv6.fib_table_hash)
1675                 goto out_rt6_stats;
1676
1677         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1678                                           GFP_KERNEL);
1679         if (!net->ipv6.fib6_main_tbl)
1680                 goto out_fib_table_hash;
1681
1682         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1683         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1684         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1685                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1686         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1687
1688 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1689         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1690                                            GFP_KERNEL);
1691         if (!net->ipv6.fib6_local_tbl)
1692                 goto out_fib6_main_tbl;
1693         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1694         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1695         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1696                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1697         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1698 #endif
1699         fib6_tables_init(net);
1700
1701         return 0;
1702
1703 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1704 out_fib6_main_tbl:
1705         kfree(net->ipv6.fib6_main_tbl);
1706 #endif
1707 out_fib_table_hash:
1708         kfree(net->ipv6.fib_table_hash);
1709 out_rt6_stats:
1710         kfree(net->ipv6.rt6_stats);
1711 out_timer:
1712         return -ENOMEM;
1713  }
1714
1715 static void fib6_net_exit(struct net *net)
1716 {
1717         rt6_ifdown(net, NULL);
1718         del_timer_sync(&net->ipv6.ip6_fib_timer);
1719
1720 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1721         inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1722         kfree(net->ipv6.fib6_local_tbl);
1723 #endif
1724         inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1725         kfree(net->ipv6.fib6_main_tbl);
1726         kfree(net->ipv6.fib_table_hash);
1727         kfree(net->ipv6.rt6_stats);
1728 }
1729
1730 static struct pernet_operations fib6_net_ops = {
1731         .init = fib6_net_init,
1732         .exit = fib6_net_exit,
1733 };
1734
1735 int __init fib6_init(void)
1736 {
1737         int ret = -ENOMEM;
1738
1739         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1740                                            sizeof(struct fib6_node),
1741                                            0, SLAB_HWCACHE_ALIGN,
1742                                            NULL);
1743         if (!fib6_node_kmem)
1744                 goto out;
1745
1746         ret = register_pernet_subsys(&fib6_net_ops);
1747         if (ret)
1748                 goto out_kmem_cache_create;
1749
1750         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1751                               NULL);
1752         if (ret)
1753                 goto out_unregister_subsys;
1754 out:
1755         return ret;
1756
1757 out_unregister_subsys:
1758         unregister_pernet_subsys(&fib6_net_ops);
1759 out_kmem_cache_create:
1760         kmem_cache_destroy(fib6_node_kmem);
1761         goto out;
1762 }
1763
1764 void fib6_gc_cleanup(void)
1765 {
1766         unregister_pernet_subsys(&fib6_net_ops);
1767         kmem_cache_destroy(fib6_node_kmem);
1768 }