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 #include <linux/errno.h>
  22 #include <linux/types.h>
  23 #include <linux/net.h>
  24 #include <linux/route.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/in6.h>
  27 #include <linux/init.h>
  28 #include <linux/list.h>
  29 #include <linux/slab.h>
  30
  31 #ifdef  CONFIG_PROC_FS
  32 #include <linux/proc_fs.h>
  33 #endif
  34
  35 #include <net/ipv6.h>
  36 #include <net/ndisc.h>
  37 #include <net/addrconf.h>
  38
  39 #include <net/ip6_fib.h>
  40 #include <net/ip6_route.h>
  41
  42 #define RT6_DEBUG 2
  43
  44 #if RT6_DEBUG >= 3
  45 #define RT6_TRACE(x...) printk(KERN_DEBUG x)
  46 #else
  47 #define RT6_TRACE(x...) do { ; } while (0)
  48 #endif
  49
  50 static struct kmem_cache * fib6_node_kmem __read_mostly;
  51
  52 enum fib_walk_state_t
  53 {
  54 #ifdef CONFIG_IPV6_SUBTREES
  55         FWS_S,
  56 #endif
  57         FWS_L,
  58         FWS_R,
  59         FWS_C,
  60         FWS_U
  61 };
  62
  63 struct fib6_cleaner_t
  64 {
  65         struct fib6_walker_t w;
  66         struct net *net;
  67         int (*func)(struct rt6_info *, void *arg);
  68         void *arg;
  69 };
  70
  71 static DEFINE_RWLOCK(fib6_walker_lock);
  72
  73 #ifdef CONFIG_IPV6_SUBTREES
  74 #define FWS_INIT FWS_S
  75 #else
  76 #define FWS_INIT FWS_L
  77 #endif
  78
  79 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
  80                               struct rt6_info *rt);
  81 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
  82 static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
  83 static int fib6_walk(struct fib6_walker_t *w);
  84 static int fib6_walk_continue(struct fib6_walker_t *w);
  85
  86 /*
  87  *      A routing update causes an increase of the serial number on the
  88  *      affected subtree. This allows for cached routes to be asynchronously
  89  *      tested when modifications are made to the destination cache as a
  90  *      result of redirects, path MTU changes, etc.
  91  */
  92
  93 static __u32 rt_sernum;
  94
  95 static void fib6_gc_timer_cb(unsigned long arg);
  96
  97 static LIST_HEAD(fib6_walkers);
  98 #define FOR_WALKERS(w) list_for_each_entry(w, &fib6_walkers, lh)
  99
 100 static inline void fib6_walker_link(struct fib6_walker_t *w)
 101 {
 102         write_lock_bh(&fib6_walker_lock);
 103         list_add(&w->lh, &fib6_walkers);
 104         write_unlock_bh(&fib6_walker_lock);
 105 }
 106
 107 static inline void fib6_walker_unlink(struct fib6_walker_t *w)
 108 {
 109         write_lock_bh(&fib6_walker_lock);
 110         list_del(&w->lh);
 111         write_unlock_bh(&fib6_walker_lock);
 112 }
 113 static __inline__ u32 fib6_new_sernum(void)
 114 {
 115         u32 n = ++rt_sernum;
 116         if ((__s32)n <= 0)
 117                 rt_sernum = n = 1;
 118         return n;
 119 }
 120
 121 /*
 122  *      Auxiliary address test functions for the radix tree.
 123  *
 124  *      These assume a 32bit processor (although it will work on
 125  *      64bit processors)
 126  */
 127
 128 /*
 129  *      test bit
 130  */
 131 #if defined(__LITTLE_ENDIAN)
 132 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
 133 #else
 134 # define BITOP_BE32_SWIZZLE     0
 135 #endif
 136
 137 static __inline__ __be32 addr_bit_set(void *token, int fn_bit)
 138 {
 139         __be32 *addr = token;
 140         /*
 141          * Here,
 142          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
 143          * is optimized version of
 144          *      htonl(1 << ((~fn_bit)&0x1F))
 145          * See include/asm-generic/bitops/le.h.
 146          */
 147         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
 148                addr[fn_bit >> 5];
 149 }
 150
 151 static __inline__ struct fib6_node * node_alloc(void)
 152 {
 153         struct fib6_node *fn;
 154
 155         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 156
 157         return fn;
 158 }
 159
 160 static __inline__ void node_free(struct fib6_node * fn)
 161 {
 162         kmem_cache_free(fib6_node_kmem, fn);
 163 }
 164
 165 static __inline__ void rt6_release(struct rt6_info *rt)
 166 {
 167         if (atomic_dec_and_test(&rt->rt6i_ref))
 168                 dst_free(&rt->u.dst);
 169 }
 170
 171 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 172 {
 173         unsigned int h;
 174
 175         /*
 176          * Initialize table lock at a single place to give lockdep a key,
 177          * tables aren't visible prior to being linked to the list.
 178          */
 179         rwlock_init(&tb->tb6_lock);
 180
 181         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 182
 183         /*
 184          * No protection necessary, this is the only list mutatation
 185          * operation, tables never disappear once they exist.
 186          */
 187         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 188 }
 189
 190 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 191
 192 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 193 {
 194         struct fib6_table *table;
 195
 196         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 197         if (table != NULL) {
 198                 table->tb6_id = id;
 199                 table->tb6_root.leaf = net->ipv6.ip6_null_entry;
 200                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 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 != NULL)
 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         struct hlist_node *node;
 228         unsigned int h;
 229
 230         if (id == 0)
 231                 id = RT6_TABLE_MAIN;
 232         h = id & (FIB6_TABLE_HASHSZ - 1);
 233         rcu_read_lock();
 234         head = &net->ipv6.fib_table_hash[h];
 235         hlist_for_each_entry_rcu(tb, node, head, tb6_hlist) {
 236                 if (tb->tb6_id == id) {
 237                         rcu_read_unlock();
 238                         return tb;
 239                 }
 240         }
 241         rcu_read_unlock();
 242
 243         return NULL;
 244 }
 245
 246 static void __net_init fib6_tables_init(struct net *net)
 247 {
 248         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 249         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 250 }
 251 #else
 252
 253 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 254 {
 255         return fib6_get_table(net, id);
 256 }
 257
 258 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 259 {
 260           return net->ipv6.fib6_main_tbl;
 261 }
 262
 263 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi *fl,
 264                                    int flags, pol_lookup_t lookup)
 265 {
 266         return (struct dst_entry *) lookup(net, net->ipv6.fib6_main_tbl, fl, flags);
 267 }
 268
 269 static void __net_init fib6_tables_init(struct net *net)
 270 {
 271         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 272 }
 273
 274 #endif
 275
 276 static int fib6_dump_node(struct fib6_walker_t *w)
 277 {
 278         int res;
 279         struct rt6_info *rt;
 280
 281         for (rt = w->leaf; rt; rt = rt->u.dst.rt6_next) {
 282                 res = rt6_dump_route(rt, w->args);
 283                 if (res < 0) {
 284                         /* Frame is full, suspend walking */
 285                         w->leaf = rt;
 286                         return 1;
 287                 }
 288                 WARN_ON(res == 0);
 289         }
 290         w->leaf = NULL;
 291         return 0;
 292 }
 293
 294 static void fib6_dump_end(struct netlink_callback *cb)
 295 {
 296         struct fib6_walker_t *w = (void*)cb->args[2];
 297
 298         if (w) {
 299                 if (cb->args[4]) {
 300                         cb->args[4] = 0;
 301                         fib6_walker_unlink(w);
 302                 }
 303                 cb->args[2] = 0;
 304                 kfree(w);
 305         }
 306         cb->done = (void*)cb->args[3];
 307         cb->args[1] = 3;
 308 }
 309
 310 static int fib6_dump_done(struct netlink_callback *cb)
 311 {
 312         fib6_dump_end(cb);
 313         return cb->done ? cb->done(cb) : 0;
 314 }
 315
 316 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 317                            struct netlink_callback *cb)
 318 {
 319         struct fib6_walker_t *w;
 320         int res;
 321
 322         w = (void *)cb->args[2];
 323         w->root = &table->tb6_root;
 324
 325         if (cb->args[4] == 0) {
 326                 w->count = 0;
 327                 w->skip = 0;
 328
 329                 read_lock_bh(&table->tb6_lock);
 330                 res = fib6_walk(w);
 331                 read_unlock_bh(&table->tb6_lock);
 332                 if (res > 0) {
 333                         cb->args[4] = 1;
 334                         cb->args[5] = w->root->fn_sernum;
 335                 }
 336         } else {
 337                 if (cb->args[5] != w->root->fn_sernum) {
 338                         /* Begin at the root if the tree changed */
 339                         cb->args[5] = w->root->fn_sernum;
 340                         w->state = FWS_INIT;
 341                         w->node = w->root;
 342                         w->skip = w->count;
 343                 } else
 344                         w->skip = 0;
 345
 346                 read_lock_bh(&table->tb6_lock);
 347                 res = fib6_walk_continue(w);
 348                 read_unlock_bh(&table->tb6_lock);
 349                 if (res <= 0) {
 350                         fib6_walker_unlink(w);
 351                         cb->args[4] = 0;
 352                 }
 353         }
 354
 355         return res;
 356 }
 357
 358 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 359 {
 360         struct net *net = sock_net(skb->sk);
 361         unsigned int h, s_h;
 362         unsigned int e = 0, s_e;
 363         struct rt6_rtnl_dump_arg arg;
 364         struct fib6_walker_t *w;
 365         struct fib6_table *tb;
 366         struct hlist_node *node;
 367         struct hlist_head *head;
 368         int res = 0;
 369
 370         s_h = cb->args[0];
 371         s_e = cb->args[1];
 372
 373         w = (void *)cb->args[2];
 374         if (w == NULL) {
 375                 /* New dump:
 376                  *
 377                  * 1. hook callback destructor.
 378                  */
 379                 cb->args[3] = (long)cb->done;
 380                 cb->done = fib6_dump_done;
 381
 382                 /*
 383                  * 2. allocate and initialize walker.
 384                  */
 385                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 386                 if (w == NULL)
 387                         return -ENOMEM;
 388                 w->func = fib6_dump_node;
 389                 cb->args[2] = (long)w;
 390         }
 391
 392         arg.skb = skb;
 393         arg.cb = cb;
 394         arg.net = net;
 395         w->args = &arg;
 396
 397         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 398                 e = 0;
 399                 head = &net->ipv6.fib_table_hash[h];
 400                 hlist_for_each_entry(tb, node, head, tb6_hlist) {
 401                         if (e < s_e)
 402                                 goto next;
 403                         res = fib6_dump_table(tb, skb, cb);
 404                         if (res != 0)
 405                                 goto out;
 406 next:
 407                         e++;
 408                 }
 409         }
 410 out:
 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)
 431 {
 432         struct fib6_node *fn, *in, *ln;
 433         struct fib6_node *pn = NULL;
 434         struct rt6key *key;
 435         int     bit;
 436         __be32  dir = 0;
 437         __u32   sernum = fib6_new_sernum();
 438
 439         RT6_TRACE("fib6_add_1\n");
 440
 441         /* insert node in tree */
 442
 443         fn = root;
 444
 445         do {
 446                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
 447
 448                 /*
 449                  *      Prefix match
 450                  */
 451                 if (plen < fn->fn_bit ||
 452                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
 453                         goto insert_above;
 454
 455                 /*
 456                  *      Exact match ?
 457                  */
 458
 459                 if (plen == fn->fn_bit) {
 460                         /* clean up an intermediate node */
 461                         if ((fn->fn_flags & RTN_RTINFO) == 0) {
 462                                 rt6_release(fn->leaf);
 463                                 fn->leaf = NULL;
 464                         }
 465
 466                         fn->fn_sernum = sernum;
 467
 468                         return fn;
 469                 }
 470
 471                 /*
 472                  *      We have more bits to go
 473                  */
 474
 475                 /* Try to walk down on tree. */
 476                 fn->fn_sernum = sernum;
 477                 dir = addr_bit_set(addr, fn->fn_bit);
 478                 pn = fn;
 479                 fn = dir ? fn->right: fn->left;
 480         } while (fn);
 481
 482         /*
 483          *      We walked to the bottom of tree.
 484          *      Create new leaf node without children.
 485          */
 486
 487         ln = node_alloc();
 488
 489         if (ln == NULL)
 490                 return NULL;
 491         ln->fn_bit = plen;
 492
 493         ln->parent = pn;
 494         ln->fn_sernum = sernum;
 495
 496         if (dir)
 497                 pn->right = ln;
 498         else
 499                 pn->left  = ln;
 500
 501         return ln;
 502
 503
 504 insert_above:
 505         /*
 506          * split since we don't have a common prefix anymore or
 507          * we have a less significant route.
 508          * we've to insert an intermediate node on the list
 509          * this new node will point to the one we need to create
 510          * and the current
 511          */
 512
 513         pn = fn->parent;
 514
 515         /* find 1st bit in difference between the 2 addrs.
 516
 517            See comment in __ipv6_addr_diff: bit may be an invalid value,
 518            but if it is >= plen, the value is ignored in any case.
 519          */
 520
 521         bit = __ipv6_addr_diff(addr, &key->addr, addrlen);
 522
 523         /*
 524          *              (intermediate)[in]
 525          *                /        \
 526          *      (new leaf node)[ln] (old node)[fn]
 527          */
 528         if (plen > bit) {
 529                 in = node_alloc();
 530                 ln = node_alloc();
 531
 532                 if (in == NULL || ln == NULL) {
 533                         if (in)
 534                                 node_free(in);
 535                         if (ln)
 536                                 node_free(ln);
 537                         return NULL;
 538                 }
 539
 540                 /*
 541                  * new intermediate node.
 542                  * RTN_RTINFO will
 543                  * be off since that an address that chooses one of
 544                  * the branches would not match less specific routes
 545                  * in the other branch
 546                  */
 547
 548                 in->fn_bit = bit;
 549
 550                 in->parent = pn;
 551                 in->leaf = fn->leaf;
 552                 atomic_inc(&in->leaf->rt6i_ref);
 553
 554                 in->fn_sernum = sernum;
 555
 556                 /* update parent pointer */
 557                 if (dir)
 558                         pn->right = in;
 559                 else
 560                         pn->left  = in;
 561
 562                 ln->fn_bit = plen;
 563
 564                 ln->parent = in;
 565                 fn->parent = in;
 566
 567                 ln->fn_sernum = sernum;
 568
 569                 if (addr_bit_set(addr, bit)) {
 570                         in->right = ln;
 571                         in->left  = fn;
 572                 } else {
 573                         in->left  = ln;
 574                         in->right = fn;
 575                 }
 576         } else { /* plen <= bit */
 577
 578                 /*
 579                  *              (new leaf node)[ln]
 580                  *                /        \
 581                  *           (old node)[fn] NULL
 582                  */
 583
 584                 ln = node_alloc();
 585
 586                 if (ln == NULL)
 587                         return NULL;
 588
 589                 ln->fn_bit = plen;
 590
 591                 ln->parent = pn;
 592
 593                 ln->fn_sernum = sernum;
 594
 595                 if (dir)
 596                         pn->right = ln;
 597                 else
 598                         pn->left  = ln;
 599
 600                 if (addr_bit_set(&key->addr, plen))
 601                         ln->right = fn;
 602                 else
 603                         ln->left  = fn;
 604
 605                 fn->parent = ln;
 606         }
 607         return ln;
 608 }
 609
 610 /*
 611  *      Insert routing information in a node.
 612  */
 613
 614 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 615                             struct nl_info *info)
 616 {
 617         struct rt6_info *iter = NULL;
 618         struct rt6_info **ins;
 619
 620         ins = &fn->leaf;
 621
 622         for (iter = fn->leaf; iter; iter=iter->u.dst.rt6_next) {
 623                 /*
 624                  *      Search for duplicates
 625                  */
 626
 627                 if (iter->rt6i_metric == rt->rt6i_metric) {
 628                         /*
 629                          *      Same priority level
 630                          */
 631
 632                         if (iter->rt6i_dev == rt->rt6i_dev &&
 633                             iter->rt6i_idev == rt->rt6i_idev &&
 634                             ipv6_addr_equal(&iter->rt6i_gateway,
 635                                             &rt->rt6i_gateway)) {
 636                                 if (!(iter->rt6i_flags&RTF_EXPIRES))
 637                                         return -EEXIST;
 638                                 iter->rt6i_expires = rt->rt6i_expires;
 639                                 if (!(rt->rt6i_flags&RTF_EXPIRES)) {
 640                                         iter->rt6i_flags &= ~RTF_EXPIRES;
 641                                         iter->rt6i_expires = 0;
 642                                 }
 643                                 return -EEXIST;
 644                         }
 645                 }
 646
 647                 if (iter->rt6i_metric > rt->rt6i_metric)
 648                         break;
 649
 650                 ins = &iter->u.dst.rt6_next;
 651         }
 652
 653         /* Reset round-robin state, if necessary */
 654         if (ins == &fn->leaf)
 655                 fn->rr_ptr = NULL;
 656
 657         /*
 658          *      insert node
 659          */
 660
 661         rt->u.dst.rt6_next = iter;
 662         *ins = rt;
 663         rt->rt6i_node = fn;
 664         atomic_inc(&rt->rt6i_ref);
 665         inet6_rt_notify(RTM_NEWROUTE, rt, info);
 666         info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 667
 668         if ((fn->fn_flags & RTN_RTINFO) == 0) {
 669                 info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 670                 fn->fn_flags |= RTN_RTINFO;
 671         }
 672
 673         return 0;
 674 }
 675
 676 static __inline__ void fib6_start_gc(struct net *net, struct rt6_info *rt)
 677 {
 678         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 679             (rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE)))
 680                 mod_timer(&net->ipv6.ip6_fib_timer,
 681                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 682 }
 683
 684 void fib6_force_start_gc(struct net *net)
 685 {
 686         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 687                 mod_timer(&net->ipv6.ip6_fib_timer,
 688                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 689 }
 690
 691 /*
 692  *      Add routing information to the routing tree.
 693  *      <destination addr>/<source addr>
 694  *      with source addr info in sub-trees
 695  */
 696
 697 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
 698 {
 699         struct fib6_node *fn, *pn = NULL;
 700         int err = -ENOMEM;
 701
 702         fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
 703                         rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst));
 704
 705         if (fn == NULL)
 706                 goto out;
 707
 708         pn = fn;
 709
 710 #ifdef CONFIG_IPV6_SUBTREES
 711         if (rt->rt6i_src.plen) {
 712                 struct fib6_node *sn;
 713
 714                 if (fn->subtree == NULL) {
 715                         struct fib6_node *sfn;
 716
 717                         /*
 718                          * Create subtree.
 719                          *
 720                          *              fn[main tree]
 721                          *              |
 722                          *              sfn[subtree root]
 723                          *                 \
 724                          *                  sn[new leaf node]
 725                          */
 726
 727                         /* Create subtree root node */
 728                         sfn = node_alloc();
 729                         if (sfn == NULL)
 730                                 goto st_failure;
 731
 732                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 733                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 734                         sfn->fn_flags = RTN_ROOT;
 735                         sfn->fn_sernum = fib6_new_sernum();
 736
 737                         /* Now add the first leaf node to new subtree */
 738
 739                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 740                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 741                                         offsetof(struct rt6_info, rt6i_src));
 742
 743                         if (sn == NULL) {
 744                                 /* If it is failed, discard just allocated
 745                                    root, and then (in st_failure) stale node
 746                                    in main tree.
 747                                  */
 748                                 node_free(sfn);
 749                                 goto st_failure;
 750                         }
 751
 752                         /* Now link new subtree to main tree */
 753                         sfn->parent = fn;
 754                         fn->subtree = sfn;
 755                 } else {
 756                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 757                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 758                                         offsetof(struct rt6_info, rt6i_src));
 759
 760                         if (sn == NULL)
 761                                 goto st_failure;
 762                 }
 763
 764                 if (fn->leaf == NULL) {
 765                         fn->leaf = rt;
 766                         atomic_inc(&rt->rt6i_ref);
 767                 }
 768                 fn = sn;
 769         }
 770 #endif
 771
 772         err = fib6_add_rt2node(fn, rt, info);
 773
 774         if (err == 0) {
 775                 fib6_start_gc(info->nl_net, rt);
 776                 if (!(rt->rt6i_flags&RTF_CACHE))
 777                         fib6_prune_clones(info->nl_net, pn, rt);
 778         }
 779
 780 out:
 781         if (err) {
 782 #ifdef CONFIG_IPV6_SUBTREES
 783                 /*
 784                  * If fib6_add_1 has cleared the old leaf pointer in the
 785                  * super-tree leaf node we have to find a new one for it.
 786                  */
 787                 if (pn != fn && pn->leaf == rt) {
 788                         pn->leaf = NULL;
 789                         atomic_dec(&rt->rt6i_ref);
 790                 }
 791                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 792                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
 793 #if RT6_DEBUG >= 2
 794                         if (!pn->leaf) {
 795                                 WARN_ON(pn->leaf == NULL);
 796                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 797                         }
 798 #endif
 799                         atomic_inc(&pn->leaf->rt6i_ref);
 800                 }
 801 #endif
 802                 dst_free(&rt->u.dst);
 803         }
 804         return err;
 805
 806 #ifdef CONFIG_IPV6_SUBTREES
 807         /* Subtree creation failed, probably main tree node
 808            is orphan. If it is, shoot it.
 809          */
 810 st_failure:
 811         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 812                 fib6_repair_tree(info->nl_net, fn);
 813         dst_free(&rt->u.dst);
 814         return err;
 815 #endif
 816 }
 817
 818 /*
 819  *      Routing tree lookup
 820  *
 821  */
 822
 823 struct lookup_args {
 824         int             offset;         /* key offset on rt6_info       */
 825         struct in6_addr *addr;          /* search key                   */
 826 };
 827
 828 static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 829                                         struct lookup_args *args)
 830 {
 831         struct fib6_node *fn;
 832         __be32 dir;
 833
 834         if (unlikely(args->offset == 0))
 835                 return NULL;
 836
 837         /*
 838          *      Descend on a tree
 839          */
 840
 841         fn = root;
 842
 843         for (;;) {
 844                 struct fib6_node *next;
 845
 846                 dir = addr_bit_set(args->addr, fn->fn_bit);
 847
 848                 next = dir ? fn->right : fn->left;
 849
 850                 if (next) {
 851                         fn = next;
 852                         continue;
 853                 }
 854
 855                 break;
 856         }
 857
 858         while(fn) {
 859                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
 860                         struct rt6key *key;
 861
 862                         key = (struct rt6key *) ((u8 *) fn->leaf +
 863                                                  args->offset);
 864
 865                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 866 #ifdef CONFIG_IPV6_SUBTREES
 867                                 if (fn->subtree)
 868                                         fn = fib6_lookup_1(fn->subtree, args + 1);
 869 #endif
 870                                 if (!fn || fn->fn_flags & RTN_RTINFO)
 871                                         return fn;
 872                         }
 873                 }
 874
 875                 if (fn->fn_flags & RTN_ROOT)
 876                         break;
 877
 878                 fn = fn->parent;
 879         }
 880
 881         return NULL;
 882 }
 883
 884 struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr,
 885                                struct in6_addr *saddr)
 886 {
 887         struct fib6_node *fn;
 888         struct lookup_args args[] = {
 889                 {
 890                         .offset = offsetof(struct rt6_info, rt6i_dst),
 891                         .addr = daddr,
 892                 },
 893 #ifdef CONFIG_IPV6_SUBTREES
 894                 {
 895                         .offset = offsetof(struct rt6_info, rt6i_src),
 896                         .addr = saddr,
 897                 },
 898 #endif
 899                 {
 900                         .offset = 0,    /* sentinel */
 901                 }
 902         };
 903
 904         fn = fib6_lookup_1(root, daddr ? args : args + 1);
 905
 906         if (fn == NULL || fn->fn_flags & RTN_TL_ROOT)
 907                 fn = root;
 908
 909         return fn;
 910 }
 911
 912 /*
 913  *      Get node with specified destination prefix (and source prefix,
 914  *      if subtrees are used)
 915  */
 916
 917
 918 static struct fib6_node * fib6_locate_1(struct fib6_node *root,
 919                                         struct in6_addr *addr,
 920                                         int plen, int offset)
 921 {
 922         struct fib6_node *fn;
 923
 924         for (fn = root; fn ; ) {
 925                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
 926
 927                 /*
 928                  *      Prefix match
 929                  */
 930                 if (plen < fn->fn_bit ||
 931                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
 932                         return NULL;
 933
 934                 if (plen == fn->fn_bit)
 935                         return fn;
 936
 937                 /*
 938                  *      We have more bits to go
 939                  */
 940                 if (addr_bit_set(addr, fn->fn_bit))
 941                         fn = fn->right;
 942                 else
 943                         fn = fn->left;
 944         }
 945         return NULL;
 946 }
 947
 948 struct fib6_node * fib6_locate(struct fib6_node *root,
 949                                struct in6_addr *daddr, int dst_len,
 950                                struct in6_addr *saddr, int src_len)
 951 {
 952         struct fib6_node *fn;
 953
 954         fn = fib6_locate_1(root, daddr, dst_len,
 955                            offsetof(struct rt6_info, rt6i_dst));
 956
 957 #ifdef CONFIG_IPV6_SUBTREES
 958         if (src_len) {
 959                 WARN_ON(saddr == NULL);
 960                 if (fn && fn->subtree)
 961                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
 962                                            offsetof(struct rt6_info, rt6i_src));
 963         }
 964 #endif
 965
 966         if (fn && fn->fn_flags&RTN_RTINFO)
 967                 return fn;
 968
 969         return NULL;
 970 }
 971
 972
 973 /*
 974  *      Deletion
 975  *
 976  */
 977
 978 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
 979 {
 980         if (fn->fn_flags&RTN_ROOT)
 981                 return net->ipv6.ip6_null_entry;
 982
 983         while(fn) {
 984                 if(fn->left)
 985                         return fn->left->leaf;
 986
 987                 if(fn->right)
 988                         return fn->right->leaf;
 989
 990                 fn = FIB6_SUBTREE(fn);
 991         }
 992         return NULL;
 993 }
 994
 995 /*
 996  *      Called to trim the tree of intermediate nodes when possible. "fn"
 997  *      is the node we want to try and remove.
 998  */
 999
1000 static struct fib6_node *fib6_repair_tree(struct net *net,
1001                                            struct fib6_node *fn)
1002 {
1003         int children;
1004         int nstate;
1005         struct fib6_node *child, *pn;
1006         struct fib6_walker_t *w;
1007         int iter = 0;
1008
1009         for (;;) {
1010                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1011                 iter++;
1012
1013                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1014                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1015                 WARN_ON(fn->leaf != NULL);
1016
1017                 children = 0;
1018                 child = NULL;
1019                 if (fn->right) child = fn->right, children |= 1;
1020                 if (fn->left) child = fn->left, children |= 2;
1021
1022                 if (children == 3 || FIB6_SUBTREE(fn)
1023 #ifdef CONFIG_IPV6_SUBTREES
1024                     /* Subtree root (i.e. fn) may have one child */
1025                     || (children && fn->fn_flags&RTN_ROOT)
1026 #endif
1027                     ) {
1028                         fn->leaf = fib6_find_prefix(net, fn);
1029 #if RT6_DEBUG >= 2
1030                         if (fn->leaf==NULL) {
1031                                 WARN_ON(!fn->leaf);
1032                                 fn->leaf = net->ipv6.ip6_null_entry;
1033                         }
1034 #endif
1035                         atomic_inc(&fn->leaf->rt6i_ref);
1036                         return fn->parent;
1037                 }
1038
1039                 pn = fn->parent;
1040 #ifdef CONFIG_IPV6_SUBTREES
1041                 if (FIB6_SUBTREE(pn) == fn) {
1042                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1043                         FIB6_SUBTREE(pn) = NULL;
1044                         nstate = FWS_L;
1045                 } else {
1046                         WARN_ON(fn->fn_flags & RTN_ROOT);
1047 #endif
1048                         if (pn->right == fn) pn->right = child;
1049                         else if (pn->left == fn) pn->left = child;
1050 #if RT6_DEBUG >= 2
1051                         else
1052                                 WARN_ON(1);
1053 #endif
1054                         if (child)
1055                                 child->parent = pn;
1056                         nstate = FWS_R;
1057 #ifdef CONFIG_IPV6_SUBTREES
1058                 }
1059 #endif
1060
1061                 read_lock(&fib6_walker_lock);
1062                 FOR_WALKERS(w) {
1063                         if (child == NULL) {
1064                                 if (w->root == fn) {
1065                                         w->root = w->node = NULL;
1066                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1067                                 } else if (w->node == fn) {
1068                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1069                                         w->node = pn;
1070                                         w->state = nstate;
1071                                 }
1072                         } else {
1073                                 if (w->root == fn) {
1074                                         w->root = child;
1075                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1076                                 }
1077                                 if (w->node == fn) {
1078                                         w->node = child;
1079                                         if (children&2) {
1080                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1081                                                 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1082                                         } else {
1083                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1084                                                 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1085                                         }
1086                                 }
1087                         }
1088                 }
1089                 read_unlock(&fib6_walker_lock);
1090
1091                 node_free(fn);
1092                 if (pn->fn_flags&RTN_RTINFO || FIB6_SUBTREE(pn))
1093                         return pn;
1094
1095                 rt6_release(pn->leaf);
1096                 pn->leaf = NULL;
1097                 fn = pn;
1098         }
1099 }
1100
1101 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1102                            struct nl_info *info)
1103 {
1104         struct fib6_walker_t *w;
1105         struct rt6_info *rt = *rtp;
1106         struct net *net = info->nl_net;
1107
1108         RT6_TRACE("fib6_del_route\n");
1109
1110         /* Unlink it */
1111         *rtp = rt->u.dst.rt6_next;
1112         rt->rt6i_node = NULL;
1113         net->ipv6.rt6_stats->fib_rt_entries--;
1114         net->ipv6.rt6_stats->fib_discarded_routes++;
1115
1116         /* Reset round-robin state, if necessary */
1117         if (fn->rr_ptr == rt)
1118                 fn->rr_ptr = NULL;
1119
1120         /* Adjust walkers */
1121         read_lock(&fib6_walker_lock);
1122         FOR_WALKERS(w) {
1123                 if (w->state == FWS_C && w->leaf == rt) {
1124                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1125                         w->leaf = rt->u.dst.rt6_next;
1126                         if (w->leaf == NULL)
1127                                 w->state = FWS_U;
1128                 }
1129         }
1130         read_unlock(&fib6_walker_lock);
1131
1132         rt->u.dst.rt6_next = NULL;
1133
1134         /* If it was last route, expunge its radix tree node */
1135         if (fn->leaf == NULL) {
1136                 fn->fn_flags &= ~RTN_RTINFO;
1137                 net->ipv6.rt6_stats->fib_route_nodes--;
1138                 fn = fib6_repair_tree(net, fn);
1139         }
1140
1141         if (atomic_read(&rt->rt6i_ref) != 1) {
1142                 /* This route is used as dummy address holder in some split
1143                  * nodes. It is not leaked, but it still holds other resources,
1144                  * which must be released in time. So, scan ascendant nodes
1145                  * and replace dummy references to this route with references
1146                  * to still alive ones.
1147                  */
1148                 while (fn) {
1149                         if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) {
1150                                 fn->leaf = fib6_find_prefix(net, fn);
1151                                 atomic_inc(&fn->leaf->rt6i_ref);
1152                                 rt6_release(rt);
1153                         }
1154                         fn = fn->parent;
1155                 }
1156                 /* No more references are possible at this point. */
1157                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1158         }
1159
1160         inet6_rt_notify(RTM_DELROUTE, rt, info);
1161         rt6_release(rt);
1162 }
1163
1164 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1165 {
1166         struct net *net = info->nl_net;
1167         struct fib6_node *fn = rt->rt6i_node;
1168         struct rt6_info **rtp;
1169
1170 #if RT6_DEBUG >= 2
1171         if (rt->u.dst.obsolete>0) {
1172                 WARN_ON(fn != NULL);
1173                 return -ENOENT;
1174         }
1175 #endif
1176         if (fn == NULL || rt == net->ipv6.ip6_null_entry)
1177                 return -ENOENT;
1178
1179         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1180
1181         if (!(rt->rt6i_flags&RTF_CACHE)) {
1182                 struct fib6_node *pn = fn;
1183 #ifdef CONFIG_IPV6_SUBTREES
1184                 /* clones of this route might be in another subtree */
1185                 if (rt->rt6i_src.plen) {
1186                         while (!(pn->fn_flags&RTN_ROOT))
1187                                 pn = pn->parent;
1188                         pn = pn->parent;
1189                 }
1190 #endif
1191                 fib6_prune_clones(info->nl_net, pn, rt);
1192         }
1193
1194         /*
1195          *      Walk the leaf entries looking for ourself
1196          */
1197
1198         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.dst.rt6_next) {
1199                 if (*rtp == rt) {
1200                         fib6_del_route(fn, rtp, info);
1201                         return 0;
1202                 }
1203         }
1204         return -ENOENT;
1205 }
1206
1207 /*
1208  *      Tree traversal function.
1209  *
1210  *      Certainly, it is not interrupt safe.
1211  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1212  *      It means, that we can modify tree during walking
1213  *      and use this function for garbage collection, clone pruning,
1214  *      cleaning tree when a device goes down etc. etc.
1215  *
1216  *      It guarantees that every node will be traversed,
1217  *      and that it will be traversed only once.
1218  *
1219  *      Callback function w->func may return:
1220  *      0 -> continue walking.
1221  *      positive value -> walking is suspended (used by tree dumps,
1222  *      and probably by gc, if it will be split to several slices)
1223  *      negative value -> terminate walking.
1224  *
1225  *      The function itself returns:
1226  *      0   -> walk is complete.
1227  *      >0  -> walk is incomplete (i.e. suspended)
1228  *      <0  -> walk is terminated by an error.
1229  */
1230
1231 static int fib6_walk_continue(struct fib6_walker_t *w)
1232 {
1233         struct fib6_node *fn, *pn;
1234
1235         for (;;) {
1236                 fn = w->node;
1237                 if (fn == NULL)
1238                         return 0;
1239
1240                 if (w->prune && fn != w->root &&
1241                     fn->fn_flags&RTN_RTINFO && w->state < FWS_C) {
1242                         w->state = FWS_C;
1243                         w->leaf = fn->leaf;
1244                 }
1245                 switch (w->state) {
1246 #ifdef CONFIG_IPV6_SUBTREES
1247                 case FWS_S:
1248                         if (FIB6_SUBTREE(fn)) {
1249                                 w->node = FIB6_SUBTREE(fn);
1250                                 continue;
1251                         }
1252                         w->state = FWS_L;
1253 #endif
1254                 case FWS_L:
1255                         if (fn->left) {
1256                                 w->node = fn->left;
1257                                 w->state = FWS_INIT;
1258                                 continue;
1259                         }
1260                         w->state = FWS_R;
1261                 case FWS_R:
1262                         if (fn->right) {
1263                                 w->node = fn->right;
1264                                 w->state = FWS_INIT;
1265                                 continue;
1266                         }
1267                         w->state = FWS_C;
1268                         w->leaf = fn->leaf;
1269                 case FWS_C:
1270                         if (w->leaf && fn->fn_flags&RTN_RTINFO) {
1271                                 int err;
1272
1273                                 if (w->count < w->skip) {
1274                                         w->count++;
1275                                         continue;
1276                                 }
1277
1278                                 err = w->func(w);
1279                                 if (err)
1280                                         return err;
1281
1282                                 w->count++;
1283                                 continue;
1284                         }
1285                         w->state = FWS_U;
1286                 case FWS_U:
1287                         if (fn == w->root)
1288                                 return 0;
1289                         pn = fn->parent;
1290                         w->node = pn;
1291 #ifdef CONFIG_IPV6_SUBTREES
1292                         if (FIB6_SUBTREE(pn) == fn) {
1293                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1294                                 w->state = FWS_L;
1295                                 continue;
1296                         }
1297 #endif
1298                         if (pn->left == fn) {
1299                                 w->state = FWS_R;
1300                                 continue;
1301                         }
1302                         if (pn->right == fn) {
1303                                 w->state = FWS_C;
1304                                 w->leaf = w->node->leaf;
1305                                 continue;
1306                         }
1307 #if RT6_DEBUG >= 2
1308                         WARN_ON(1);
1309 #endif
1310                 }
1311         }
1312 }
1313
1314 static int fib6_walk(struct fib6_walker_t *w)
1315 {
1316         int res;
1317
1318         w->state = FWS_INIT;
1319         w->node = w->root;
1320
1321         fib6_walker_link(w);
1322         res = fib6_walk_continue(w);
1323         if (res <= 0)
1324                 fib6_walker_unlink(w);
1325         return res;
1326 }
1327
1328 static int fib6_clean_node(struct fib6_walker_t *w)
1329 {
1330         int res;
1331         struct rt6_info *rt;
1332         struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1333         struct nl_info info = {
1334                 .nl_net = c->net,
1335         };
1336
1337         for (rt = w->leaf; rt; rt = rt->u.dst.rt6_next) {
1338                 res = c->func(rt, c->arg);
1339                 if (res < 0) {
1340                         w->leaf = rt;
1341                         res = fib6_del(rt, &info);
1342                         if (res) {
1343 #if RT6_DEBUG >= 2
1344                                 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
1345 #endif
1346                                 continue;
1347                         }
1348                         return 0;
1349                 }
1350                 WARN_ON(res != 0);
1351         }
1352         w->leaf = rt;
1353         return 0;
1354 }
1355
1356 /*
1357  *      Convenient frontend to tree walker.
1358  *
1359  *      func is called on each route.
1360  *              It may return -1 -> delete this route.
1361  *                            0  -> continue walking
1362  *
1363  *      prune==1 -> only immediate children of node (certainly,
1364  *      ignoring pure split nodes) will be scanned.
1365  */
1366
1367 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1368                             int (*func)(struct rt6_info *, void *arg),
1369                             int prune, void *arg)
1370 {
1371         struct fib6_cleaner_t c;
1372
1373         c.w.root = root;
1374         c.w.func = fib6_clean_node;
1375         c.w.prune = prune;
1376         c.w.count = 0;
1377         c.w.skip = 0;
1378         c.func = func;
1379         c.arg = arg;
1380         c.net = net;
1381
1382         fib6_walk(&c.w);
1383 }
1384
1385 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
1386                     int prune, void *arg)
1387 {
1388         struct fib6_table *table;
1389         struct hlist_node *node;
1390         struct hlist_head *head;
1391         unsigned int h;
1392
1393         rcu_read_lock();
1394         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1395                 head = &net->ipv6.fib_table_hash[h];
1396                 hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1397                         write_lock_bh(&table->tb6_lock);
1398                         fib6_clean_tree(net, &table->tb6_root,
1399                                         func, prune, arg);
1400                         write_unlock_bh(&table->tb6_lock);
1401                 }
1402         }
1403         rcu_read_unlock();
1404 }
1405
1406 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1407 {
1408         if (rt->rt6i_flags & RTF_CACHE) {
1409                 RT6_TRACE("pruning clone %p\n", rt);
1410                 return -1;
1411         }
1412
1413         return 0;
1414 }
1415
1416 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
1417                               struct rt6_info *rt)
1418 {
1419         fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
1420 }
1421
1422 /*
1423  *      Garbage collection
1424  */
1425
1426 static struct fib6_gc_args
1427 {
1428         int                     timeout;
1429         int                     more;
1430 } gc_args;
1431
1432 static int fib6_age(struct rt6_info *rt, void *arg)
1433 {
1434         unsigned long now = jiffies;
1435
1436         /*
1437          *      check addrconf expiration here.
1438          *      Routes are expired even if they are in use.
1439          *
1440          *      Also age clones. Note, that clones are aged out
1441          *      only if they are not in use now.
1442          */
1443
1444         if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {
1445                 if (time_after(now, rt->rt6i_expires)) {
1446                         RT6_TRACE("expiring %p\n", rt);
1447                         return -1;
1448                 }
1449                 gc_args.more++;
1450         } else if (rt->rt6i_flags & RTF_CACHE) {
1451                 if (atomic_read(&rt->u.dst.__refcnt) == 0 &&
1452                     time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) {
1453                         RT6_TRACE("aging clone %p\n", rt);
1454                         return -1;
1455                 } else if ((rt->rt6i_flags & RTF_GATEWAY) &&
1456                            (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) {
1457                         RT6_TRACE("purging route %p via non-router but gateway\n",
1458                                   rt);
1459                         return -1;
1460                 }
1461                 gc_args.more++;
1462         }
1463
1464         return 0;
1465 }
1466
1467 static DEFINE_SPINLOCK(fib6_gc_lock);
1468
1469 void fib6_run_gc(unsigned long expires, struct net *net)
1470 {
1471         if (expires != ~0UL) {
1472                 spin_lock_bh(&fib6_gc_lock);
1473                 gc_args.timeout = expires ? (int)expires :
1474                         net->ipv6.sysctl.ip6_rt_gc_interval;
1475         } else {
1476                 if (!spin_trylock_bh(&fib6_gc_lock)) {
1477                         mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1478                         return;
1479                 }
1480                 gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
1481         }
1482
1483         gc_args.more = icmp6_dst_gc();
1484
1485         fib6_clean_all(net, fib6_age, 0, NULL);
1486
1487         if (gc_args.more)
1488                 mod_timer(&net->ipv6.ip6_fib_timer,
1489                           round_jiffies(jiffies
1490                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1491         else
1492                 del_timer(&net->ipv6.ip6_fib_timer);
1493         spin_unlock_bh(&fib6_gc_lock);
1494 }
1495
1496 static void fib6_gc_timer_cb(unsigned long arg)
1497 {
1498         fib6_run_gc(0, (struct net *)arg);
1499 }
1500
1501 static int __net_init fib6_net_init(struct net *net)
1502 {
1503         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1504
1505         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1506         if (!net->ipv6.rt6_stats)
1507                 goto out_timer;
1508
1509         net->ipv6.fib_table_hash = kcalloc(FIB6_TABLE_HASHSZ,
1510                                            sizeof(*net->ipv6.fib_table_hash),
1511                                            GFP_KERNEL);
1512         if (!net->ipv6.fib_table_hash)
1513                 goto out_rt6_stats;
1514
1515         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1516                                           GFP_KERNEL);
1517         if (!net->ipv6.fib6_main_tbl)
1518                 goto out_fib_table_hash;
1519
1520         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1521         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1522         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1523                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1524
1525 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1526         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1527                                            GFP_KERNEL);
1528         if (!net->ipv6.fib6_local_tbl)
1529                 goto out_fib6_main_tbl;
1530         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1531         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1532         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1533                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1534 #endif
1535         fib6_tables_init(net);
1536
1537         return 0;
1538
1539 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1540 out_fib6_main_tbl:
1541         kfree(net->ipv6.fib6_main_tbl);
1542 #endif
1543 out_fib_table_hash:
1544         kfree(net->ipv6.fib_table_hash);
1545 out_rt6_stats:
1546         kfree(net->ipv6.rt6_stats);
1547 out_timer:
1548         return -ENOMEM;
1549  }
1550
1551 static void fib6_net_exit(struct net *net)
1552 {
1553         rt6_ifdown(net, NULL);
1554         del_timer_sync(&net->ipv6.ip6_fib_timer);
1555
1556 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1557         kfree(net->ipv6.fib6_local_tbl);
1558 #endif
1559         kfree(net->ipv6.fib6_main_tbl);
1560         kfree(net->ipv6.fib_table_hash);
1561         kfree(net->ipv6.rt6_stats);
1562 }
1563
1564 static struct pernet_operations fib6_net_ops = {
1565         .init = fib6_net_init,
1566         .exit = fib6_net_exit,
1567 };
1568
1569 int __init fib6_init(void)
1570 {
1571         int ret = -ENOMEM;
1572
1573         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1574                                            sizeof(struct fib6_node),
1575                                            0, SLAB_HWCACHE_ALIGN,
1576                                            NULL);
1577         if (!fib6_node_kmem)
1578                 goto out;
1579
1580         ret = register_pernet_subsys(&fib6_net_ops);
1581         if (ret)
1582                 goto out_kmem_cache_create;
1583
1584         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib);
1585         if (ret)
1586                 goto out_unregister_subsys;
1587 out:
1588         return ret;
1589
1590 out_unregister_subsys:
1591         unregister_pernet_subsys(&fib6_net_ops);
1592 out_kmem_cache_create:
1593         kmem_cache_destroy(fib6_node_kmem);
1594         goto out;
1595 }
1596
1597 void fib6_gc_cleanup(void)
1598 {
1599         unregister_pernet_subsys(&fib6_net_ops);
1600         kmem_cache_destroy(fib6_node_kmem);
1601 }