net/ipv6/ip6_fib.c

   1 /*
   2  *      Linux INET6 implementation
   3  *      Forwarding Information Database
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <[email protected]>
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  */
  13
  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 #include <net/ipv6.h>
  32 #include <net/ndisc.h>
  33 #include <net/addrconf.h>
  34
  35 #include <net/ip6_fib.h>
  36 #include <net/ip6_route.h>
  37
  38 #define RT6_DEBUG 2
  39
  40 #if RT6_DEBUG >= 3
  41 #define RT6_TRACE(x...) printk(KERN_DEBUG x)
  42 #else
  43 #define RT6_TRACE(x...) do { ; } while (0)
  44 #endif
  45
  46 static struct kmem_cache * fib6_node_kmem __read_mostly;
  47
  48 enum fib_walk_state_t
  49 {
  50 #ifdef CONFIG_IPV6_SUBTREES
  51         FWS_S,
  52 #endif
  53         FWS_L,
  54         FWS_R,
  55         FWS_C,
  56         FWS_U
  57 };
  58
  59 struct fib6_cleaner_t
  60 {
  61         struct fib6_walker_t w;
  62         struct net *net;
  63         int (*func)(struct rt6_info *, void *arg);
  64         void *arg;
  65 };
  66
  67 static DEFINE_RWLOCK(fib6_walker_lock);
  68
  69 #ifdef CONFIG_IPV6_SUBTREES
  70 #define FWS_INIT FWS_S
  71 #else
  72 #define FWS_INIT FWS_L
  73 #endif
  74
  75 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
  76                               struct rt6_info *rt);
  77 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
  78 static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
  79 static int fib6_walk(struct fib6_walker_t *w);
  80 static int fib6_walk_continue(struct fib6_walker_t *w);
  81
  82 /*
  83  *      A routing update causes an increase of the serial number on the
  84  *      affected subtree. This allows for cached routes to be asynchronously
  85  *      tested when modifications are made to the destination cache as a
  86  *      result of redirects, path MTU changes, etc.
  87  */
  88
  89 static __u32 rt_sernum;
  90
  91 static void fib6_gc_timer_cb(unsigned long arg);
  92
  93 static LIST_HEAD(fib6_walkers);
  94 #define FOR_WALKERS(w) list_for_each_entry(w, &fib6_walkers, lh)
  95
  96 static inline void fib6_walker_link(struct fib6_walker_t *w)
  97 {
  98         write_lock_bh(&fib6_walker_lock);
  99         list_add(&w->lh, &fib6_walkers);
 100         write_unlock_bh(&fib6_walker_lock);
 101 }
 102
 103 static inline void fib6_walker_unlink(struct fib6_walker_t *w)
 104 {
 105         write_lock_bh(&fib6_walker_lock);
 106         list_del(&w->lh);
 107         write_unlock_bh(&fib6_walker_lock);
 108 }
 109 static __inline__ u32 fib6_new_sernum(void)
 110 {
 111         u32 n = ++rt_sernum;
 112         if ((__s32)n <= 0)
 113                 rt_sernum = n = 1;
 114         return n;
 115 }
 116
 117 /*
 118  *      Auxiliary address test functions for the radix tree.
 119  *
 120  *      These assume a 32bit processor (although it will work on
 121  *      64bit processors)
 122  */
 123
 124 /*
 125  *      test bit
 126  */
 127 #if defined(__LITTLE_ENDIAN)
 128 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
 129 #else
 130 # define BITOP_BE32_SWIZZLE     0
 131 #endif
 132
 133 static __inline__ __be32 addr_bit_set(const void *token, int fn_bit)
 134 {
 135         const __be32 *addr = token;
 136         /*
 137          * Here,
 138          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
 139          * is optimized version of
 140          *      htonl(1 << ((~fn_bit)&0x1F))
 141          * See include/asm-generic/bitops/le.h.
 142          */
 143         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
 144                addr[fn_bit >> 5];
 145 }
 146
 147 static __inline__ struct fib6_node * node_alloc(void)
 148 {
 149         struct fib6_node *fn;
 150
 151         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 152
 153         return fn;
 154 }
 155
 156 static __inline__ void node_free(struct fib6_node * fn)
 157 {
 158         kmem_cache_free(fib6_node_kmem, fn);
 159 }
 160
 161 static __inline__ void rt6_release(struct rt6_info *rt)
 162 {
 163         if (atomic_dec_and_test(&rt->rt6i_ref))
 164                 dst_free(&rt->dst);
 165 }
 166
 167 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 168 {
 169         unsigned int h;
 170
 171         /*
 172          * Initialize table lock at a single place to give lockdep a key,
 173          * tables aren't visible prior to being linked to the list.
 174          */
 175         rwlock_init(&tb->tb6_lock);
 176
 177         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 178
 179         /*
 180          * No protection necessary, this is the only list mutatation
 181          * operation, tables never disappear once they exist.
 182          */
 183         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 184 }
 185
 186 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 187
 188 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 189 {
 190         struct fib6_table *table;
 191
 192         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 193         if (table) {
 194                 table->tb6_id = id;
 195                 table->tb6_root.leaf = net->ipv6.ip6_null_entry;
 196                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 197         }
 198
 199         return table;
 200 }
 201
 202 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 203 {
 204         struct fib6_table *tb;
 205
 206         if (id == 0)
 207                 id = RT6_TABLE_MAIN;
 208         tb = fib6_get_table(net, id);
 209         if (tb)
 210                 return tb;
 211
 212         tb = fib6_alloc_table(net, id);
 213         if (tb)
 214                 fib6_link_table(net, tb);
 215
 216         return tb;
 217 }
 218
 219 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 220 {
 221         struct fib6_table *tb;
 222         struct hlist_head *head;
 223         struct hlist_node *node;
 224         unsigned int h;
 225
 226         if (id == 0)
 227                 id = RT6_TABLE_MAIN;
 228         h = id & (FIB6_TABLE_HASHSZ - 1);
 229         rcu_read_lock();
 230         head = &net->ipv6.fib_table_hash[h];
 231         hlist_for_each_entry_rcu(tb, node, head, tb6_hlist) {
 232                 if (tb->tb6_id == id) {
 233                         rcu_read_unlock();
 234                         return tb;
 235                 }
 236         }
 237         rcu_read_unlock();
 238
 239         return NULL;
 240 }
 241
 242 static void __net_init fib6_tables_init(struct net *net)
 243 {
 244         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 245         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 246 }
 247 #else
 248
 249 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 250 {
 251         return fib6_get_table(net, id);
 252 }
 253
 254 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 255 {
 256           return net->ipv6.fib6_main_tbl;
 257 }
 258
 259 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 260                                    int flags, pol_lookup_t lookup)
 261 {
 262         return (struct dst_entry *) lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
 263 }
 264
 265 static void __net_init fib6_tables_init(struct net *net)
 266 {
 267         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 268 }
 269
 270 #endif
 271
 272 static int fib6_dump_node(struct fib6_walker_t *w)
 273 {
 274         int res;
 275         struct rt6_info *rt;
 276
 277         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
 278                 res = rt6_dump_route(rt, w->args);
 279                 if (res < 0) {
 280                         /* Frame is full, suspend walking */
 281                         w->leaf = rt;
 282                         return 1;
 283                 }
 284                 WARN_ON(res == 0);
 285         }
 286         w->leaf = NULL;
 287         return 0;
 288 }
 289
 290 static void fib6_dump_end(struct netlink_callback *cb)
 291 {
 292         struct fib6_walker_t *w = (void*)cb->args[2];
 293
 294         if (w) {
 295                 if (cb->args[4]) {
 296                         cb->args[4] = 0;
 297                         fib6_walker_unlink(w);
 298                 }
 299                 cb->args[2] = 0;
 300                 kfree(w);
 301         }
 302         cb->done = (void*)cb->args[3];
 303         cb->args[1] = 3;
 304 }
 305
 306 static int fib6_dump_done(struct netlink_callback *cb)
 307 {
 308         fib6_dump_end(cb);
 309         return cb->done ? cb->done(cb) : 0;
 310 }
 311
 312 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 313                            struct netlink_callback *cb)
 314 {
 315         struct fib6_walker_t *w;
 316         int res;
 317
 318         w = (void *)cb->args[2];
 319         w->root = &table->tb6_root;
 320
 321         if (cb->args[4] == 0) {
 322                 w->count = 0;
 323                 w->skip = 0;
 324
 325                 read_lock_bh(&table->tb6_lock);
 326                 res = fib6_walk(w);
 327                 read_unlock_bh(&table->tb6_lock);
 328                 if (res > 0) {
 329                         cb->args[4] = 1;
 330                         cb->args[5] = w->root->fn_sernum;
 331                 }
 332         } else {
 333                 if (cb->args[5] != w->root->fn_sernum) {
 334                         /* Begin at the root if the tree changed */
 335                         cb->args[5] = w->root->fn_sernum;
 336                         w->state = FWS_INIT;
 337                         w->node = w->root;
 338                         w->skip = w->count;
 339                 } else
 340                         w->skip = 0;
 341
 342                 read_lock_bh(&table->tb6_lock);
 343                 res = fib6_walk_continue(w);
 344                 read_unlock_bh(&table->tb6_lock);
 345                 if (res <= 0) {
 346                         fib6_walker_unlink(w);
 347                         cb->args[4] = 0;
 348                 }
 349         }
 350
 351         return res;
 352 }
 353
 354 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 355 {
 356         struct net *net = sock_net(skb->sk);
 357         unsigned int h, s_h;
 358         unsigned int e = 0, s_e;
 359         struct rt6_rtnl_dump_arg arg;
 360         struct fib6_walker_t *w;
 361         struct fib6_table *tb;
 362         struct hlist_node *node;
 363         struct hlist_head *head;
 364         int res = 0;
 365
 366         s_h = cb->args[0];
 367         s_e = cb->args[1];
 368
 369         w = (void *)cb->args[2];
 370         if (!w) {
 371                 /* New dump:
 372                  *
 373                  * 1. hook callback destructor.
 374                  */
 375                 cb->args[3] = (long)cb->done;
 376                 cb->done = fib6_dump_done;
 377
 378                 /*
 379                  * 2. allocate and initialize walker.
 380                  */
 381                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 382                 if (!w)
 383                         return -ENOMEM;
 384                 w->func = fib6_dump_node;
 385                 cb->args[2] = (long)w;
 386         }
 387
 388         arg.skb = skb;
 389         arg.cb = cb;
 390         arg.net = net;
 391         w->args = &arg;
 392
 393         rcu_read_lock();
 394         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 395                 e = 0;
 396                 head = &net->ipv6.fib_table_hash[h];
 397                 hlist_for_each_entry_rcu(tb, node, head, tb6_hlist) {
 398                         if (e < s_e)
 399                                 goto next;
 400                         res = fib6_dump_table(tb, skb, cb);
 401                         if (res != 0)
 402                                 goto out;
 403 next:
 404                         e++;
 405                 }
 406         }
 407 out:
 408         rcu_read_unlock();
 409         cb->args[1] = e;
 410         cb->args[0] = h;
 411
 412         res = res < 0 ? res : skb->len;
 413         if (res <= 0)
 414                 fib6_dump_end(cb);
 415         return res;
 416 }
 417
 418 /*
 419  *      Routing Table
 420  *
 421  *      return the appropriate node for a routing tree "add" operation
 422  *      by either creating and inserting or by returning an existing
 423  *      node.
 424  */
 425
 426 static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
 427                                      int addrlen, int plen,
 428                                      int offset, int allow_create,
 429                                      int replace_required)
 430 {
 431         struct fib6_node *fn, *in, *ln;
 432         struct fib6_node *pn = NULL;
 433         struct rt6key *key;
 434         int     bit;
 435         __be32  dir = 0;
 436         __u32   sernum = fib6_new_sernum();
 437
 438         RT6_TRACE("fib6_add_1\n");
 439
 440         /* insert node in tree */
 441
 442         fn = root;
 443
 444         do {
 445                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
 446
 447                 /*
 448                  *      Prefix match
 449                  */
 450                 if (plen < fn->fn_bit ||
 451                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 452                         if (!allow_create) {
 453                                 if (replace_required) {
 454                                         pr_warn("IPv6: Can't replace route, "
 455                                                 "no match found\n");
 456                                         return ERR_PTR(-ENOENT);
 457                                 }
 458                                 pr_warn("IPv6: NLM_F_CREATE should be set "
 459                                         "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("IPv6: Can't replace route, no match found\n");
 503                         return ERR_PTR(-ENOENT);
 504                 }
 505                 pr_warn("IPv6: NLM_F_CREATE should be set "
 506                         "when creating new route\n");
 507         }
 508         /*
 509          *      We walked to the bottom of tree.
 510          *      Create new leaf node without children.
 511          */
 512
 513         ln = node_alloc();
 514
 515         if (!ln)
 516                 return NULL;
 517         ln->fn_bit = plen;
 518
 519         ln->parent = pn;
 520         ln->fn_sernum = sernum;
 521
 522         if (dir)
 523                 pn->right = ln;
 524         else
 525                 pn->left  = ln;
 526
 527         return ln;
 528
 529
 530 insert_above:
 531         /*
 532          * split since we don't have a common prefix anymore or
 533          * we have a less significant route.
 534          * we've to insert an intermediate node on the list
 535          * this new node will point to the one we need to create
 536          * and the current
 537          */
 538
 539         pn = fn->parent;
 540
 541         /* find 1st bit in difference between the 2 addrs.
 542
 543            See comment in __ipv6_addr_diff: bit may be an invalid value,
 544            but if it is >= plen, the value is ignored in any case.
 545          */
 546
 547         bit = __ipv6_addr_diff(addr, &key->addr, addrlen);
 548
 549         /*
 550          *              (intermediate)[in]
 551          *                /        \
 552          *      (new leaf node)[ln] (old node)[fn]
 553          */
 554         if (plen > bit) {
 555                 in = node_alloc();
 556                 ln = node_alloc();
 557
 558                 if (!in || !ln) {
 559                         if (in)
 560                                 node_free(in);
 561                         if (ln)
 562                                 node_free(ln);
 563                         return NULL;
 564                 }
 565
 566                 /*
 567                  * new intermediate node.
 568                  * RTN_RTINFO will
 569                  * be off since that an address that chooses one of
 570                  * the branches would not match less specific routes
 571                  * in the other branch
 572                  */
 573
 574                 in->fn_bit = bit;
 575
 576                 in->parent = pn;
 577                 in->leaf = fn->leaf;
 578                 atomic_inc(&in->leaf->rt6i_ref);
 579
 580                 in->fn_sernum = sernum;
 581
 582                 /* update parent pointer */
 583                 if (dir)
 584                         pn->right = in;
 585                 else
 586                         pn->left  = in;
 587
 588                 ln->fn_bit = plen;
 589
 590                 ln->parent = in;
 591                 fn->parent = in;
 592
 593                 ln->fn_sernum = sernum;
 594
 595                 if (addr_bit_set(addr, bit)) {
 596                         in->right = ln;
 597                         in->left  = fn;
 598                 } else {
 599                         in->left  = ln;
 600                         in->right = fn;
 601                 }
 602         } else { /* plen <= bit */
 603
 604                 /*
 605                  *              (new leaf node)[ln]
 606                  *                /        \
 607                  *           (old node)[fn] NULL
 608                  */
 609
 610                 ln = node_alloc();
 611
 612                 if (!ln)
 613                         return NULL;
 614
 615                 ln->fn_bit = plen;
 616
 617                 ln->parent = pn;
 618
 619                 ln->fn_sernum = sernum;
 620
 621                 if (dir)
 622                         pn->right = ln;
 623                 else
 624                         pn->left  = ln;
 625
 626                 if (addr_bit_set(&key->addr, plen))
 627                         ln->right = fn;
 628                 else
 629                         ln->left  = fn;
 630
 631                 fn->parent = ln;
 632         }
 633         return ln;
 634 }
 635
 636 /*
 637  *      Insert routing information in a node.
 638  */
 639
 640 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 641                             struct nl_info *info)
 642 {
 643         struct rt6_info *iter = NULL;
 644         struct rt6_info **ins;
 645         int replace = (info->nlh &&
 646                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 647         int add = (!info->nlh ||
 648                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
 649         int found = 0;
 650
 651         ins = &fn->leaf;
 652
 653         for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
 654                 /*
 655                  *      Search for duplicates
 656                  */
 657
 658                 if (iter->rt6i_metric == rt->rt6i_metric) {
 659                         /*
 660                          *      Same priority level
 661                          */
 662                         if (info->nlh &&
 663                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
 664                                 return -EEXIST;
 665                         if (replace) {
 666                                 found++;
 667                                 break;
 668                         }
 669
 670                         if (iter->dst.dev == rt->dst.dev &&
 671                             iter->rt6i_idev == rt->rt6i_idev &&
 672                             ipv6_addr_equal(&iter->rt6i_gateway,
 673                                             &rt->rt6i_gateway)) {
 674                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
 675                                         return -EEXIST;
 676                                 iter->dst.expires = rt->dst.expires;
 677                                 if (!(rt->rt6i_flags & RTF_EXPIRES)) {
 678                                         iter->rt6i_flags &= ~RTF_EXPIRES;
 679                                         iter->dst.expires = 0;
 680                                 }
 681                                 return -EEXIST;
 682                         }
 683                 }
 684
 685                 if (iter->rt6i_metric > rt->rt6i_metric)
 686                         break;
 687
 688                 ins = &iter->dst.rt6_next;
 689         }
 690
 691         /* Reset round-robin state, if necessary */
 692         if (ins == &fn->leaf)
 693                 fn->rr_ptr = NULL;
 694
 695         /*
 696          *      insert node
 697          */
 698         if (!replace) {
 699                 if (!add)
 700                         pr_warn("IPv6: NLM_F_CREATE should be set when creating new route\n");
 701
 702 add:
 703                 rt->dst.rt6_next = iter;
 704                 *ins = rt;
 705                 rt->rt6i_node = fn;
 706                 atomic_inc(&rt->rt6i_ref);
 707                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 708                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 709
 710                 if (!(fn->fn_flags & RTN_RTINFO)) {
 711                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 712                         fn->fn_flags |= RTN_RTINFO;
 713                 }
 714
 715         } else {
 716                 if (!found) {
 717                         if (add)
 718                                 goto add;
 719                         pr_warn("IPv6: NLM_F_REPLACE set, but no existing node found!\n");
 720                         return -ENOENT;
 721                 }
 722                 *ins = rt;
 723                 rt->rt6i_node = fn;
 724                 rt->dst.rt6_next = iter->dst.rt6_next;
 725                 atomic_inc(&rt->rt6i_ref);
 726                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 727                 rt6_release(iter);
 728                 if (!(fn->fn_flags & RTN_RTINFO)) {
 729                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 730                         fn->fn_flags |= RTN_RTINFO;
 731                 }
 732         }
 733
 734         return 0;
 735 }
 736
 737 static __inline__ void fib6_start_gc(struct net *net, struct rt6_info *rt)
 738 {
 739         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 740             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 741                 mod_timer(&net->ipv6.ip6_fib_timer,
 742                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 743 }
 744
 745 void fib6_force_start_gc(struct net *net)
 746 {
 747         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 748                 mod_timer(&net->ipv6.ip6_fib_timer,
 749                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 750 }
 751
 752 /*
 753  *      Add routing information to the routing tree.
 754  *      <destination addr>/<source addr>
 755  *      with source addr info in sub-trees
 756  */
 757
 758 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
 759 {
 760         struct fib6_node *fn, *pn = NULL;
 761         int err = -ENOMEM;
 762         int allow_create = 1;
 763         int replace_required = 0;
 764
 765         if (info->nlh) {
 766                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 767                         allow_create = 0;
 768                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 769                         replace_required = 1;
 770         }
 771         if (!allow_create && !replace_required)
 772                 pr_warn("IPv6: RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 773
 774         fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
 775                         rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst),
 776                         allow_create, replace_required);
 777
 778         if (IS_ERR(fn)) {
 779                 err = PTR_ERR(fn);
 780                 fn = NULL;
 781         }
 782
 783         if (!fn)
 784                 goto out;
 785
 786         pn = fn;
 787
 788 #ifdef CONFIG_IPV6_SUBTREES
 789         if (rt->rt6i_src.plen) {
 790                 struct fib6_node *sn;
 791
 792                 if (!fn->subtree) {
 793                         struct fib6_node *sfn;
 794
 795                         /*
 796                          * Create subtree.
 797                          *
 798                          *              fn[main tree]
 799                          *              |
 800                          *              sfn[subtree root]
 801                          *                 \
 802                          *                  sn[new leaf node]
 803                          */
 804
 805                         /* Create subtree root node */
 806                         sfn = node_alloc();
 807                         if (!sfn)
 808                                 goto st_failure;
 809
 810                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 811                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 812                         sfn->fn_flags = RTN_ROOT;
 813                         sfn->fn_sernum = fib6_new_sernum();
 814
 815                         /* Now add the first leaf node to new subtree */
 816
 817                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 818                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 819                                         offsetof(struct rt6_info, rt6i_src),
 820                                         allow_create, replace_required);
 821
 822                         if (!sn) {
 823                                 /* If it is failed, discard just allocated
 824                                    root, and then (in st_failure) stale node
 825                                    in main tree.
 826                                  */
 827                                 node_free(sfn);
 828                                 goto st_failure;
 829                         }
 830
 831                         /* Now link new subtree to main tree */
 832                         sfn->parent = fn;
 833                         fn->subtree = sfn;
 834                 } else {
 835                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 836                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 837                                         offsetof(struct rt6_info, rt6i_src),
 838                                         allow_create, replace_required);
 839
 840                         if (IS_ERR(sn)) {
 841                                 err = PTR_ERR(sn);
 842                                 sn = NULL;
 843                         }
 844                         if (!sn)
 845                                 goto st_failure;
 846                 }
 847
 848                 if (!fn->leaf) {
 849                         fn->leaf = rt;
 850                         atomic_inc(&rt->rt6i_ref);
 851                 }
 852                 fn = sn;
 853         }
 854 #endif
 855
 856         err = fib6_add_rt2node(fn, rt, info);
 857         if (!err) {
 858                 fib6_start_gc(info->nl_net, rt);
 859                 if (!(rt->rt6i_flags & RTF_CACHE))
 860                         fib6_prune_clones(info->nl_net, pn, rt);
 861         }
 862
 863 out:
 864         if (err) {
 865 #ifdef CONFIG_IPV6_SUBTREES
 866                 /*
 867                  * If fib6_add_1 has cleared the old leaf pointer in the
 868                  * super-tree leaf node we have to find a new one for it.
 869                  */
 870                 if (pn != fn && pn->leaf == rt) {
 871                         pn->leaf = NULL;
 872                         atomic_dec(&rt->rt6i_ref);
 873                 }
 874                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 875                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
 876 #if RT6_DEBUG >= 2
 877                         if (!pn->leaf) {
 878                                 WARN_ON(pn->leaf == NULL);
 879                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 880                         }
 881 #endif
 882                         atomic_inc(&pn->leaf->rt6i_ref);
 883                 }
 884 #endif
 885                 dst_free(&rt->dst);
 886         }
 887         return err;
 888
 889 #ifdef CONFIG_IPV6_SUBTREES
 890         /* Subtree creation failed, probably main tree node
 891            is orphan. If it is, shoot it.
 892          */
 893 st_failure:
 894         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 895                 fib6_repair_tree(info->nl_net, fn);
 896         dst_free(&rt->dst);
 897         return err;
 898 #endif
 899 }
 900
 901 /*
 902  *      Routing tree lookup
 903  *
 904  */
 905
 906 struct lookup_args {
 907         int                     offset;         /* key offset on rt6_info       */
 908         const struct in6_addr   *addr;          /* search key                   */
 909 };
 910
 911 static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 912                                         struct lookup_args *args)
 913 {
 914         struct fib6_node *fn;
 915         __be32 dir;
 916
 917         if (unlikely(args->offset == 0))
 918                 return NULL;
 919
 920         /*
 921          *      Descend on a tree
 922          */
 923
 924         fn = root;
 925
 926         for (;;) {
 927                 struct fib6_node *next;
 928
 929                 dir = addr_bit_set(args->addr, fn->fn_bit);
 930
 931                 next = dir ? fn->right : fn->left;
 932
 933                 if (next) {
 934                         fn = next;
 935                         continue;
 936                 }
 937                 break;
 938         }
 939
 940         while (fn) {
 941                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
 942                         struct rt6key *key;
 943
 944                         key = (struct rt6key *) ((u8 *) fn->leaf +
 945                                                  args->offset);
 946
 947                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 948 #ifdef CONFIG_IPV6_SUBTREES
 949                                 if (fn->subtree)
 950                                         fn = fib6_lookup_1(fn->subtree, args + 1);
 951 #endif
 952                                 if (!fn || fn->fn_flags & RTN_RTINFO)
 953                                         return fn;
 954                         }
 955                 }
 956
 957                 if (fn->fn_flags & RTN_ROOT)
 958                         break;
 959
 960                 fn = fn->parent;
 961         }
 962
 963         return NULL;
 964 }
 965
 966 struct fib6_node * fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
 967                                const struct in6_addr *saddr)
 968 {
 969         struct fib6_node *fn;
 970         struct lookup_args args[] = {
 971                 {
 972                         .offset = offsetof(struct rt6_info, rt6i_dst),
 973                         .addr = daddr,
 974                 },
 975 #ifdef CONFIG_IPV6_SUBTREES
 976                 {
 977                         .offset = offsetof(struct rt6_info, rt6i_src),
 978                         .addr = saddr,
 979                 },
 980 #endif
 981                 {
 982                         .offset = 0,    /* sentinel */
 983                 }
 984         };
 985
 986         fn = fib6_lookup_1(root, daddr ? args : args + 1);
 987         if (!fn || fn->fn_flags & RTN_TL_ROOT)
 988                 fn = root;
 989
 990         return fn;
 991 }
 992
 993 /*
 994  *      Get node with specified destination prefix (and source prefix,
 995  *      if subtrees are used)
 996  */
 997
 998
 999 static struct fib6_node * fib6_locate_1(struct fib6_node *root,
1000                                         const struct in6_addr *addr,
1001                                         int plen, int offset)
1002 {
1003         struct fib6_node *fn;
1004
1005         for (fn = root; fn ; ) {
1006                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1007
1008                 /*
1009                  *      Prefix match
1010                  */
1011                 if (plen < fn->fn_bit ||
1012                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1013                         return NULL;
1014
1015                 if (plen == fn->fn_bit)
1016                         return fn;
1017
1018                 /*
1019                  *      We have more bits to go
1020                  */
1021                 if (addr_bit_set(addr, fn->fn_bit))
1022                         fn = fn->right;
1023                 else
1024                         fn = fn->left;
1025         }
1026         return NULL;
1027 }
1028
1029 struct fib6_node * fib6_locate(struct fib6_node *root,
1030                                const struct in6_addr *daddr, int dst_len,
1031                                const struct in6_addr *saddr, int src_len)
1032 {
1033         struct fib6_node *fn;
1034
1035         fn = fib6_locate_1(root, daddr, dst_len,
1036                            offsetof(struct rt6_info, rt6i_dst));
1037
1038 #ifdef CONFIG_IPV6_SUBTREES
1039         if (src_len) {
1040                 WARN_ON(saddr == NULL);
1041                 if (fn && fn->subtree)
1042                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
1043                                            offsetof(struct rt6_info, rt6i_src));
1044         }
1045 #endif
1046
1047         if (fn && fn->fn_flags & RTN_RTINFO)
1048                 return fn;
1049
1050         return NULL;
1051 }
1052
1053
1054 /*
1055  *      Deletion
1056  *
1057  */
1058
1059 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1060 {
1061         if (fn->fn_flags & RTN_ROOT)
1062                 return net->ipv6.ip6_null_entry;
1063
1064         while (fn) {
1065                 if (fn->left)
1066                         return fn->left->leaf;
1067                 if (fn->right)
1068                         return fn->right->leaf;
1069
1070                 fn = FIB6_SUBTREE(fn);
1071         }
1072         return NULL;
1073 }
1074
1075 /*
1076  *      Called to trim the tree of intermediate nodes when possible. "fn"
1077  *      is the node we want to try and remove.
1078  */
1079
1080 static struct fib6_node *fib6_repair_tree(struct net *net,
1081                                            struct fib6_node *fn)
1082 {
1083         int children;
1084         int nstate;
1085         struct fib6_node *child, *pn;
1086         struct fib6_walker_t *w;
1087         int iter = 0;
1088
1089         for (;;) {
1090                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1091                 iter++;
1092
1093                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1094                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1095                 WARN_ON(fn->leaf != NULL);
1096
1097                 children = 0;
1098                 child = NULL;
1099                 if (fn->right) child = fn->right, children |= 1;
1100                 if (fn->left) child = fn->left, children |= 2;
1101
1102                 if (children == 3 || FIB6_SUBTREE(fn)
1103 #ifdef CONFIG_IPV6_SUBTREES
1104                     /* Subtree root (i.e. fn) may have one child */
1105                     || (children && fn->fn_flags & RTN_ROOT)
1106 #endif
1107                     ) {
1108                         fn->leaf = fib6_find_prefix(net, fn);
1109 #if RT6_DEBUG >= 2
1110                         if (!fn->leaf) {
1111                                 WARN_ON(!fn->leaf);
1112                                 fn->leaf = net->ipv6.ip6_null_entry;
1113                         }
1114 #endif
1115                         atomic_inc(&fn->leaf->rt6i_ref);
1116                         return fn->parent;
1117                 }
1118
1119                 pn = fn->parent;
1120 #ifdef CONFIG_IPV6_SUBTREES
1121                 if (FIB6_SUBTREE(pn) == fn) {
1122                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1123                         FIB6_SUBTREE(pn) = NULL;
1124                         nstate = FWS_L;
1125                 } else {
1126                         WARN_ON(fn->fn_flags & RTN_ROOT);
1127 #endif
1128                         if (pn->right == fn) pn->right = child;
1129                         else if (pn->left == fn) pn->left = child;
1130 #if RT6_DEBUG >= 2
1131                         else
1132                                 WARN_ON(1);
1133 #endif
1134                         if (child)
1135                                 child->parent = pn;
1136                         nstate = FWS_R;
1137 #ifdef CONFIG_IPV6_SUBTREES
1138                 }
1139 #endif
1140
1141                 read_lock(&fib6_walker_lock);
1142                 FOR_WALKERS(w) {
1143                         if (!child) {
1144                                 if (w->root == fn) {
1145                                         w->root = w->node = NULL;
1146                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1147                                 } else if (w->node == fn) {
1148                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1149                                         w->node = pn;
1150                                         w->state = nstate;
1151                                 }
1152                         } else {
1153                                 if (w->root == fn) {
1154                                         w->root = child;
1155                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1156                                 }
1157                                 if (w->node == fn) {
1158                                         w->node = child;
1159                                         if (children&2) {
1160                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1161                                                 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1162                                         } else {
1163                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1164                                                 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1165                                         }
1166                                 }
1167                         }
1168                 }
1169                 read_unlock(&fib6_walker_lock);
1170
1171                 node_free(fn);
1172                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1173                         return pn;
1174
1175                 rt6_release(pn->leaf);
1176                 pn->leaf = NULL;
1177                 fn = pn;
1178         }
1179 }
1180
1181 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1182                            struct nl_info *info)
1183 {
1184         struct fib6_walker_t *w;
1185         struct rt6_info *rt = *rtp;
1186         struct net *net = info->nl_net;
1187
1188         RT6_TRACE("fib6_del_route\n");
1189
1190         /* Unlink it */
1191         *rtp = rt->dst.rt6_next;
1192         rt->rt6i_node = NULL;
1193         net->ipv6.rt6_stats->fib_rt_entries--;
1194         net->ipv6.rt6_stats->fib_discarded_routes++;
1195
1196         /* Reset round-robin state, if necessary */
1197         if (fn->rr_ptr == rt)
1198                 fn->rr_ptr = NULL;
1199
1200         /* Adjust walkers */
1201         read_lock(&fib6_walker_lock);
1202         FOR_WALKERS(w) {
1203                 if (w->state == FWS_C && w->leaf == rt) {
1204                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1205                         w->leaf = rt->dst.rt6_next;
1206                         if (!w->leaf)
1207                                 w->state = FWS_U;
1208                 }
1209         }
1210         read_unlock(&fib6_walker_lock);
1211
1212         rt->dst.rt6_next = NULL;
1213
1214         /* If it was last route, expunge its radix tree node */
1215         if (!fn->leaf) {
1216                 fn->fn_flags &= ~RTN_RTINFO;
1217                 net->ipv6.rt6_stats->fib_route_nodes--;
1218                 fn = fib6_repair_tree(net, fn);
1219         }
1220
1221         if (atomic_read(&rt->rt6i_ref) != 1) {
1222                 /* This route is used as dummy address holder in some split
1223                  * nodes. It is not leaked, but it still holds other resources,
1224                  * which must be released in time. So, scan ascendant nodes
1225                  * and replace dummy references to this route with references
1226                  * to still alive ones.
1227                  */
1228                 while (fn) {
1229                         if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
1230                                 fn->leaf = fib6_find_prefix(net, fn);
1231                                 atomic_inc(&fn->leaf->rt6i_ref);
1232                                 rt6_release(rt);
1233                         }
1234                         fn = fn->parent;
1235                 }
1236                 /* No more references are possible at this point. */
1237                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1238         }
1239
1240         inet6_rt_notify(RTM_DELROUTE, rt, info);
1241         rt6_release(rt);
1242 }
1243
1244 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1245 {
1246         struct net *net = info->nl_net;
1247         struct fib6_node *fn = rt->rt6i_node;
1248         struct rt6_info **rtp;
1249
1250 #if RT6_DEBUG >= 2
1251         if (rt->dst.obsolete>0) {
1252                 WARN_ON(fn != NULL);
1253                 return -ENOENT;
1254         }
1255 #endif
1256         if (!fn || rt == net->ipv6.ip6_null_entry)
1257                 return -ENOENT;
1258
1259         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1260
1261         if (!(rt->rt6i_flags & RTF_CACHE)) {
1262                 struct fib6_node *pn = fn;
1263 #ifdef CONFIG_IPV6_SUBTREES
1264                 /* clones of this route might be in another subtree */
1265                 if (rt->rt6i_src.plen) {
1266                         while (!(pn->fn_flags & RTN_ROOT))
1267                                 pn = pn->parent;
1268                         pn = pn->parent;
1269                 }
1270 #endif
1271                 fib6_prune_clones(info->nl_net, pn, rt);
1272         }
1273
1274         /*
1275          *      Walk the leaf entries looking for ourself
1276          */
1277
1278         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1279                 if (*rtp == rt) {
1280                         fib6_del_route(fn, rtp, info);
1281                         return 0;
1282                 }
1283         }
1284         return -ENOENT;
1285 }
1286
1287 /*
1288  *      Tree traversal function.
1289  *
1290  *      Certainly, it is not interrupt safe.
1291  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1292  *      It means, that we can modify tree during walking
1293  *      and use this function for garbage collection, clone pruning,
1294  *      cleaning tree when a device goes down etc. etc.
1295  *
1296  *      It guarantees that every node will be traversed,
1297  *      and that it will be traversed only once.
1298  *
1299  *      Callback function w->func may return:
1300  *      0 -> continue walking.
1301  *      positive value -> walking is suspended (used by tree dumps,
1302  *      and probably by gc, if it will be split to several slices)
1303  *      negative value -> terminate walking.
1304  *
1305  *      The function itself returns:
1306  *      0   -> walk is complete.
1307  *      >0  -> walk is incomplete (i.e. suspended)
1308  *      <0  -> walk is terminated by an error.
1309  */
1310
1311 static int fib6_walk_continue(struct fib6_walker_t *w)
1312 {
1313         struct fib6_node *fn, *pn;
1314
1315         for (;;) {
1316                 fn = w->node;
1317                 if (!fn)
1318                         return 0;
1319
1320                 if (w->prune && fn != w->root &&
1321                     fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1322                         w->state = FWS_C;
1323                         w->leaf = fn->leaf;
1324                 }
1325                 switch (w->state) {
1326 #ifdef CONFIG_IPV6_SUBTREES
1327                 case FWS_S:
1328                         if (FIB6_SUBTREE(fn)) {
1329                                 w->node = FIB6_SUBTREE(fn);
1330                                 continue;
1331                         }
1332                         w->state = FWS_L;
1333 #endif
1334                 case FWS_L:
1335                         if (fn->left) {
1336                                 w->node = fn->left;
1337                                 w->state = FWS_INIT;
1338                                 continue;
1339                         }
1340                         w->state = FWS_R;
1341                 case FWS_R:
1342                         if (fn->right) {
1343                                 w->node = fn->right;
1344                                 w->state = FWS_INIT;
1345                                 continue;
1346                         }
1347                         w->state = FWS_C;
1348                         w->leaf = fn->leaf;
1349                 case FWS_C:
1350                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1351                                 int err;
1352
1353                                 if (w->count < w->skip) {
1354                                         w->count++;
1355                                         continue;
1356                                 }
1357
1358                                 err = w->func(w);
1359                                 if (err)
1360                                         return err;
1361
1362                                 w->count++;
1363                                 continue;
1364                         }
1365                         w->state = FWS_U;
1366                 case FWS_U:
1367                         if (fn == w->root)
1368                                 return 0;
1369                         pn = fn->parent;
1370                         w->node = pn;
1371 #ifdef CONFIG_IPV6_SUBTREES
1372                         if (FIB6_SUBTREE(pn) == fn) {
1373                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1374                                 w->state = FWS_L;
1375                                 continue;
1376                         }
1377 #endif
1378                         if (pn->left == fn) {
1379                                 w->state = FWS_R;
1380                                 continue;
1381                         }
1382                         if (pn->right == fn) {
1383                                 w->state = FWS_C;
1384                                 w->leaf = w->node->leaf;
1385                                 continue;
1386                         }
1387 #if RT6_DEBUG >= 2
1388                         WARN_ON(1);
1389 #endif
1390                 }
1391         }
1392 }
1393
1394 static int fib6_walk(struct fib6_walker_t *w)
1395 {
1396         int res;
1397
1398         w->state = FWS_INIT;
1399         w->node = w->root;
1400
1401         fib6_walker_link(w);
1402         res = fib6_walk_continue(w);
1403         if (res <= 0)
1404                 fib6_walker_unlink(w);
1405         return res;
1406 }
1407
1408 static int fib6_clean_node(struct fib6_walker_t *w)
1409 {
1410         int res;
1411         struct rt6_info *rt;
1412         struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1413         struct nl_info info = {
1414                 .nl_net = c->net,
1415         };
1416
1417         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1418                 res = c->func(rt, c->arg);
1419                 if (res < 0) {
1420                         w->leaf = rt;
1421                         res = fib6_del(rt, &info);
1422                         if (res) {
1423 #if RT6_DEBUG >= 2
1424                                 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
1425 #endif
1426                                 continue;
1427                         }
1428                         return 0;
1429                 }
1430                 WARN_ON(res != 0);
1431         }
1432         w->leaf = rt;
1433         return 0;
1434 }
1435
1436 /*
1437  *      Convenient frontend to tree walker.
1438  *
1439  *      func is called on each route.
1440  *              It may return -1 -> delete this route.
1441  *                            0  -> continue walking
1442  *
1443  *      prune==1 -> only immediate children of node (certainly,
1444  *      ignoring pure split nodes) will be scanned.
1445  */
1446
1447 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1448                             int (*func)(struct rt6_info *, void *arg),
1449                             int prune, void *arg)
1450 {
1451         struct fib6_cleaner_t c;
1452
1453         c.w.root = root;
1454         c.w.func = fib6_clean_node;
1455         c.w.prune = prune;
1456         c.w.count = 0;
1457         c.w.skip = 0;
1458         c.func = func;
1459         c.arg = arg;
1460         c.net = net;
1461
1462         fib6_walk(&c.w);
1463 }
1464
1465 void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg),
1466                     int prune, void *arg)
1467 {
1468         struct fib6_table *table;
1469         struct hlist_node *node;
1470         struct hlist_head *head;
1471         unsigned int h;
1472
1473         rcu_read_lock();
1474         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1475                 head = &net->ipv6.fib_table_hash[h];
1476                 hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1477                         read_lock_bh(&table->tb6_lock);
1478                         fib6_clean_tree(net, &table->tb6_root,
1479                                         func, prune, arg);
1480                         read_unlock_bh(&table->tb6_lock);
1481                 }
1482         }
1483         rcu_read_unlock();
1484 }
1485 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
1486                     int prune, void *arg)
1487 {
1488         struct fib6_table *table;
1489         struct hlist_node *node;
1490         struct hlist_head *head;
1491         unsigned int h;
1492
1493         rcu_read_lock();
1494         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1495                 head = &net->ipv6.fib_table_hash[h];
1496                 hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1497                         write_lock_bh(&table->tb6_lock);
1498                         fib6_clean_tree(net, &table->tb6_root,
1499                                         func, prune, arg);
1500                         write_unlock_bh(&table->tb6_lock);
1501                 }
1502         }
1503         rcu_read_unlock();
1504 }
1505
1506 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1507 {
1508         if (rt->rt6i_flags & RTF_CACHE) {
1509                 RT6_TRACE("pruning clone %p\n", rt);
1510                 return -1;
1511         }
1512
1513         return 0;
1514 }
1515
1516 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
1517                               struct rt6_info *rt)
1518 {
1519         fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
1520 }
1521
1522 /*
1523  *      Garbage collection
1524  */
1525
1526 static struct fib6_gc_args
1527 {
1528         int                     timeout;
1529         int                     more;
1530 } gc_args;
1531
1532 static int fib6_age(struct rt6_info *rt, void *arg)
1533 {
1534         unsigned long now = jiffies;
1535
1536         /*
1537          *      check addrconf expiration here.
1538          *      Routes are expired even if they are in use.
1539          *
1540          *      Also age clones. Note, that clones are aged out
1541          *      only if they are not in use now.
1542          */
1543
1544         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1545                 if (time_after(now, rt->dst.expires)) {
1546                         RT6_TRACE("expiring %p\n", rt);
1547                         return -1;
1548                 }
1549                 gc_args.more++;
1550         } else if (rt->rt6i_flags & RTF_CACHE) {
1551                 if (atomic_read(&rt->dst.__refcnt) == 0 &&
1552                     time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1553                         RT6_TRACE("aging clone %p\n", rt);
1554                         return -1;
1555                 } else if (rt->rt6i_flags & RTF_GATEWAY) {
1556                         struct neighbour *neigh;
1557                         __u8 neigh_flags = 0;
1558
1559                         neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1560                         if (neigh) {
1561                                 neigh_flags = neigh->flags;
1562                                 neigh_release(neigh);
1563                         }
1564                         if (neigh_flags & NTF_ROUTER) {
1565                                 RT6_TRACE("purging route %p via non-router but gateway\n",
1566                                           rt);
1567                                 return -1;
1568                         }
1569                 }
1570                 gc_args.more++;
1571         }
1572
1573         return 0;
1574 }
1575
1576 static DEFINE_SPINLOCK(fib6_gc_lock);
1577
1578 void fib6_run_gc(unsigned long expires, struct net *net)
1579 {
1580         if (expires != ~0UL) {
1581                 spin_lock_bh(&fib6_gc_lock);
1582                 gc_args.timeout = expires ? (int)expires :
1583                         net->ipv6.sysctl.ip6_rt_gc_interval;
1584         } else {
1585                 if (!spin_trylock_bh(&fib6_gc_lock)) {
1586                         mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1587                         return;
1588                 }
1589                 gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
1590         }
1591
1592         gc_args.more = icmp6_dst_gc();
1593
1594         fib6_clean_all(net, fib6_age, 0, NULL);
1595
1596         if (gc_args.more)
1597                 mod_timer(&net->ipv6.ip6_fib_timer,
1598                           round_jiffies(jiffies
1599                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1600         else
1601                 del_timer(&net->ipv6.ip6_fib_timer);
1602         spin_unlock_bh(&fib6_gc_lock);
1603 }
1604
1605 static void fib6_gc_timer_cb(unsigned long arg)
1606 {
1607         fib6_run_gc(0, (struct net *)arg);
1608 }
1609
1610 static int __net_init fib6_net_init(struct net *net)
1611 {
1612         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1613
1614         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1615
1616         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1617         if (!net->ipv6.rt6_stats)
1618                 goto out_timer;
1619
1620         /* Avoid false sharing : Use at least a full cache line */
1621         size = max_t(size_t, size, L1_CACHE_BYTES);
1622
1623         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1624         if (!net->ipv6.fib_table_hash)
1625                 goto out_rt6_stats;
1626
1627         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1628                                           GFP_KERNEL);
1629         if (!net->ipv6.fib6_main_tbl)
1630                 goto out_fib_table_hash;
1631
1632         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1633         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1634         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1635                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1636
1637 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1638         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1639                                            GFP_KERNEL);
1640         if (!net->ipv6.fib6_local_tbl)
1641                 goto out_fib6_main_tbl;
1642         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1643         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1644         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1645                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1646 #endif
1647         fib6_tables_init(net);
1648
1649         return 0;
1650
1651 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1652 out_fib6_main_tbl:
1653         kfree(net->ipv6.fib6_main_tbl);
1654 #endif
1655 out_fib_table_hash:
1656         kfree(net->ipv6.fib_table_hash);
1657 out_rt6_stats:
1658         kfree(net->ipv6.rt6_stats);
1659 out_timer:
1660         return -ENOMEM;
1661  }
1662
1663 static void fib6_net_exit(struct net *net)
1664 {
1665         rt6_ifdown(net, NULL);
1666         del_timer_sync(&net->ipv6.ip6_fib_timer);
1667
1668 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1669         kfree(net->ipv6.fib6_local_tbl);
1670 #endif
1671         kfree(net->ipv6.fib6_main_tbl);
1672         kfree(net->ipv6.fib_table_hash);
1673         kfree(net->ipv6.rt6_stats);
1674 }
1675
1676 static struct pernet_operations fib6_net_ops = {
1677         .init = fib6_net_init,
1678         .exit = fib6_net_exit,
1679 };
1680
1681 int __init fib6_init(void)
1682 {
1683         int ret = -ENOMEM;
1684
1685         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1686                                            sizeof(struct fib6_node),
1687                                            0, SLAB_HWCACHE_ALIGN,
1688                                            NULL);
1689         if (!fib6_node_kmem)
1690                 goto out;
1691
1692         ret = register_pernet_subsys(&fib6_net_ops);
1693         if (ret)
1694                 goto out_kmem_cache_create;
1695
1696         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1697                               NULL);
1698         if (ret)
1699                 goto out_unregister_subsys;
1700 out:
1701         return ret;
1702
1703 out_unregister_subsys:
1704         unregister_pernet_subsys(&fib6_net_ops);
1705 out_kmem_cache_create:
1706         kmem_cache_destroy(fib6_node_kmem);
1707         goto out;
1708 }
1709
1710 void fib6_gc_cleanup(void)
1711 {
1712         unregister_pernet_subsys(&fib6_net_ops);
1713         kmem_cache_destroy(fib6_node_kmem);
1714 }