Pileus Git - ~andy/linux/blob - 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 #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                                 if (!(rt->rt6i_flags & RTF_EXPIRES))
 677                                         rt6_clean_expires(iter);
 678                                 else
 679                                         rt6_set_expires(iter, rt->dst.expires);
 680                                 return -EEXIST;
 681                         }
 682                 }
 683
 684                 if (iter->rt6i_metric > rt->rt6i_metric)
 685                         break;
 686
 687                 ins = &iter->dst.rt6_next;
 688         }
 689
 690         /* Reset round-robin state, if necessary */
 691         if (ins == &fn->leaf)
 692                 fn->rr_ptr = NULL;
 693
 694         /*
 695          *      insert node
 696          */
 697         if (!replace) {
 698                 if (!add)
 699                         pr_warn("IPv6: NLM_F_CREATE should be set when creating new route\n");
 700
 701 add:
 702                 rt->dst.rt6_next = iter;
 703                 *ins = rt;
 704                 rt->rt6i_node = fn;
 705                 atomic_inc(&rt->rt6i_ref);
 706                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 707                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 708
 709                 if (!(fn->fn_flags & RTN_RTINFO)) {
 710                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 711                         fn->fn_flags |= RTN_RTINFO;
 712                 }
 713
 714         } else {
 715                 if (!found) {
 716                         if (add)
 717                                 goto add;
 718                         pr_warn("IPv6: NLM_F_REPLACE set, but no existing node found!\n");
 719                         return -ENOENT;
 720                 }
 721                 *ins = rt;
 722                 rt->rt6i_node = fn;
 723                 rt->dst.rt6_next = iter->dst.rt6_next;
 724                 atomic_inc(&rt->rt6i_ref);
 725                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 726                 rt6_release(iter);
 727                 if (!(fn->fn_flags & RTN_RTINFO)) {
 728                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 729                         fn->fn_flags |= RTN_RTINFO;
 730                 }
 731         }
 732
 733         return 0;
 734 }
 735
 736 static __inline__ void fib6_start_gc(struct net *net, struct rt6_info *rt)
 737 {
 738         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 739             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 740                 mod_timer(&net->ipv6.ip6_fib_timer,
 741                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 742 }
 743
 744 void fib6_force_start_gc(struct net *net)
 745 {
 746         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 747                 mod_timer(&net->ipv6.ip6_fib_timer,
 748                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 749 }
 750
 751 /*
 752  *      Add routing information to the routing tree.
 753  *      <destination addr>/<source addr>
 754  *      with source addr info in sub-trees
 755  */
 756
 757 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
 758 {
 759         struct fib6_node *fn, *pn = NULL;
 760         int err = -ENOMEM;
 761         int allow_create = 1;
 762         int replace_required = 0;
 763
 764         if (info->nlh) {
 765                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 766                         allow_create = 0;
 767                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 768                         replace_required = 1;
 769         }
 770         if (!allow_create && !replace_required)
 771                 pr_warn("IPv6: RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 772
 773         fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
 774                         rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst),
 775                         allow_create, replace_required);
 776
 777         if (IS_ERR(fn)) {
 778                 err = PTR_ERR(fn);
 779                 fn = NULL;
 780         }
 781
 782         if (!fn)
 783                 goto out;
 784
 785         pn = fn;
 786
 787 #ifdef CONFIG_IPV6_SUBTREES
 788         if (rt->rt6i_src.plen) {
 789                 struct fib6_node *sn;
 790
 791                 if (!fn->subtree) {
 792                         struct fib6_node *sfn;
 793
 794                         /*
 795                          * Create subtree.
 796                          *
 797                          *              fn[main tree]
 798                          *              |
 799                          *              sfn[subtree root]
 800                          *                 \
 801                          *                  sn[new leaf node]
 802                          */
 803
 804                         /* Create subtree root node */
 805                         sfn = node_alloc();
 806                         if (!sfn)
 807                                 goto st_failure;
 808
 809                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 810                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 811                         sfn->fn_flags = RTN_ROOT;
 812                         sfn->fn_sernum = fib6_new_sernum();
 813
 814                         /* Now add the first leaf node to new subtree */
 815
 816                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 817                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 818                                         offsetof(struct rt6_info, rt6i_src),
 819                                         allow_create, replace_required);
 820
 821                         if (!sn) {
 822                                 /* If it is failed, discard just allocated
 823                                    root, and then (in st_failure) stale node
 824                                    in main tree.
 825                                  */
 826                                 node_free(sfn);
 827                                 goto st_failure;
 828                         }
 829
 830                         /* Now link new subtree to main tree */
 831                         sfn->parent = fn;
 832                         fn->subtree = sfn;
 833                 } else {
 834                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 835                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 836                                         offsetof(struct rt6_info, rt6i_src),
 837                                         allow_create, replace_required);
 838
 839                         if (IS_ERR(sn)) {
 840                                 err = PTR_ERR(sn);
 841                                 sn = NULL;
 842                         }
 843                         if (!sn)
 844                                 goto st_failure;
 845                 }
 846
 847                 if (!fn->leaf) {
 848                         fn->leaf = rt;
 849                         atomic_inc(&rt->rt6i_ref);
 850                 }
 851                 fn = sn;
 852         }
 853 #endif
 854
 855         err = fib6_add_rt2node(fn, rt, info);
 856         if (!err) {
 857                 fib6_start_gc(info->nl_net, rt);
 858                 if (!(rt->rt6i_flags & RTF_CACHE))
 859                         fib6_prune_clones(info->nl_net, pn, rt);
 860         }
 861
 862 out:
 863         if (err) {
 864 #ifdef CONFIG_IPV6_SUBTREES
 865                 /*
 866                  * If fib6_add_1 has cleared the old leaf pointer in the
 867                  * super-tree leaf node we have to find a new one for it.
 868                  */
 869                 if (pn != fn && pn->leaf == rt) {
 870                         pn->leaf = NULL;
 871                         atomic_dec(&rt->rt6i_ref);
 872                 }
 873                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 874                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
 875 #if RT6_DEBUG >= 2
 876                         if (!pn->leaf) {
 877                                 WARN_ON(pn->leaf == NULL);
 878                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 879                         }
 880 #endif
 881                         atomic_inc(&pn->leaf->rt6i_ref);
 882                 }
 883 #endif
 884                 dst_free(&rt->dst);
 885         }
 886         return err;
 887
 888 #ifdef CONFIG_IPV6_SUBTREES
 889         /* Subtree creation failed, probably main tree node
 890            is orphan. If it is, shoot it.
 891          */
 892 st_failure:
 893         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 894                 fib6_repair_tree(info->nl_net, fn);
 895         dst_free(&rt->dst);
 896         return err;
 897 #endif
 898 }
 899
 900 /*
 901  *      Routing tree lookup
 902  *
 903  */
 904
 905 struct lookup_args {
 906         int                     offset;         /* key offset on rt6_info       */
 907         const struct in6_addr   *addr;          /* search key                   */
 908 };
 909
 910 static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 911                                         struct lookup_args *args)
 912 {
 913         struct fib6_node *fn;
 914         __be32 dir;
 915
 916         if (unlikely(args->offset == 0))
 917                 return NULL;
 918
 919         /*
 920          *      Descend on a tree
 921          */
 922
 923         fn = root;
 924
 925         for (;;) {
 926                 struct fib6_node *next;
 927
 928                 dir = addr_bit_set(args->addr, fn->fn_bit);
 929
 930                 next = dir ? fn->right : fn->left;
 931
 932                 if (next) {
 933                         fn = next;
 934                         continue;
 935                 }
 936                 break;
 937         }
 938
 939         while (fn) {
 940                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
 941                         struct rt6key *key;
 942
 943                         key = (struct rt6key *) ((u8 *) fn->leaf +
 944                                                  args->offset);
 945
 946                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 947 #ifdef CONFIG_IPV6_SUBTREES
 948                                 if (fn->subtree)
 949                                         fn = fib6_lookup_1(fn->subtree, args + 1);
 950 #endif
 951                                 if (!fn || fn->fn_flags & RTN_RTINFO)
 952                                         return fn;
 953                         }
 954                 }
 955
 956                 if (fn->fn_flags & RTN_ROOT)
 957                         break;
 958
 959                 fn = fn->parent;
 960         }
 961
 962         return NULL;
 963 }
 964
 965 struct fib6_node * fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
 966                                const struct in6_addr *saddr)
 967 {
 968         struct fib6_node *fn;
 969         struct lookup_args args[] = {
 970                 {
 971                         .offset = offsetof(struct rt6_info, rt6i_dst),
 972                         .addr = daddr,
 973                 },
 974 #ifdef CONFIG_IPV6_SUBTREES
 975                 {
 976                         .offset = offsetof(struct rt6_info, rt6i_src),
 977                         .addr = saddr,
 978                 },
 979 #endif
 980                 {
 981                         .offset = 0,    /* sentinel */
 982                 }
 983         };
 984
 985         fn = fib6_lookup_1(root, daddr ? args : args + 1);
 986         if (!fn || fn->fn_flags & RTN_TL_ROOT)
 987                 fn = root;
 988
 989         return fn;
 990 }
 991
 992 /*
 993  *      Get node with specified destination prefix (and source prefix,
 994  *      if subtrees are used)
 995  */
 996
 997
 998 static struct fib6_node * fib6_locate_1(struct fib6_node *root,
 999                                         const struct in6_addr *addr,
1000                                         int plen, int offset)
1001 {
1002         struct fib6_node *fn;
1003
1004         for (fn = root; fn ; ) {
1005                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1006
1007                 /*
1008                  *      Prefix match
1009                  */
1010                 if (plen < fn->fn_bit ||
1011                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1012                         return NULL;
1013
1014                 if (plen == fn->fn_bit)
1015                         return fn;
1016
1017                 /*
1018                  *      We have more bits to go
1019                  */
1020                 if (addr_bit_set(addr, fn->fn_bit))
1021                         fn = fn->right;
1022                 else
1023                         fn = fn->left;
1024         }
1025         return NULL;
1026 }
1027
1028 struct fib6_node * fib6_locate(struct fib6_node *root,
1029                                const struct in6_addr *daddr, int dst_len,
1030                                const struct in6_addr *saddr, int src_len)
1031 {
1032         struct fib6_node *fn;
1033
1034         fn = fib6_locate_1(root, daddr, dst_len,
1035                            offsetof(struct rt6_info, rt6i_dst));
1036
1037 #ifdef CONFIG_IPV6_SUBTREES
1038         if (src_len) {
1039                 WARN_ON(saddr == NULL);
1040                 if (fn && fn->subtree)
1041                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
1042                                            offsetof(struct rt6_info, rt6i_src));
1043         }
1044 #endif
1045
1046         if (fn && fn->fn_flags & RTN_RTINFO)
1047                 return fn;
1048
1049         return NULL;
1050 }
1051
1052
1053 /*
1054  *      Deletion
1055  *
1056  */
1057
1058 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1059 {
1060         if (fn->fn_flags & RTN_ROOT)
1061                 return net->ipv6.ip6_null_entry;
1062
1063         while (fn) {
1064                 if (fn->left)
1065                         return fn->left->leaf;
1066                 if (fn->right)
1067                         return fn->right->leaf;
1068
1069                 fn = FIB6_SUBTREE(fn);
1070         }
1071         return NULL;
1072 }
1073
1074 /*
1075  *      Called to trim the tree of intermediate nodes when possible. "fn"
1076  *      is the node we want to try and remove.
1077  */
1078
1079 static struct fib6_node *fib6_repair_tree(struct net *net,
1080                                            struct fib6_node *fn)
1081 {
1082         int children;
1083         int nstate;
1084         struct fib6_node *child, *pn;
1085         struct fib6_walker_t *w;
1086         int iter = 0;
1087
1088         for (;;) {
1089                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1090                 iter++;
1091
1092                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1093                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1094                 WARN_ON(fn->leaf != NULL);
1095
1096                 children = 0;
1097                 child = NULL;
1098                 if (fn->right) child = fn->right, children |= 1;
1099                 if (fn->left) child = fn->left, children |= 2;
1100
1101                 if (children == 3 || FIB6_SUBTREE(fn)
1102 #ifdef CONFIG_IPV6_SUBTREES
1103                     /* Subtree root (i.e. fn) may have one child */
1104                     || (children && fn->fn_flags & RTN_ROOT)
1105 #endif
1106                     ) {
1107                         fn->leaf = fib6_find_prefix(net, fn);
1108 #if RT6_DEBUG >= 2
1109                         if (!fn->leaf) {
1110                                 WARN_ON(!fn->leaf);
1111                                 fn->leaf = net->ipv6.ip6_null_entry;
1112                         }
1113 #endif
1114                         atomic_inc(&fn->leaf->rt6i_ref);
1115                         return fn->parent;
1116                 }
1117
1118                 pn = fn->parent;
1119 #ifdef CONFIG_IPV6_SUBTREES
1120                 if (FIB6_SUBTREE(pn) == fn) {
1121                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1122                         FIB6_SUBTREE(pn) = NULL;
1123                         nstate = FWS_L;
1124                 } else {
1125                         WARN_ON(fn->fn_flags & RTN_ROOT);
1126 #endif
1127                         if (pn->right == fn) pn->right = child;
1128                         else if (pn->left == fn) pn->left = child;
1129 #if RT6_DEBUG >= 2
1130                         else
1131                                 WARN_ON(1);
1132 #endif
1133                         if (child)
1134                                 child->parent = pn;
1135                         nstate = FWS_R;
1136 #ifdef CONFIG_IPV6_SUBTREES
1137                 }
1138 #endif
1139
1140                 read_lock(&fib6_walker_lock);
1141                 FOR_WALKERS(w) {
1142                         if (!child) {
1143                                 if (w->root == fn) {
1144                                         w->root = w->node = NULL;
1145                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1146                                 } else if (w->node == fn) {
1147                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1148                                         w->node = pn;
1149                                         w->state = nstate;
1150                                 }
1151                         } else {
1152                                 if (w->root == fn) {
1153                                         w->root = child;
1154                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1155                                 }
1156                                 if (w->node == fn) {
1157                                         w->node = child;
1158                                         if (children&2) {
1159                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1160                                                 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1161                                         } else {
1162                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1163                                                 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1164                                         }
1165                                 }
1166                         }
1167                 }
1168                 read_unlock(&fib6_walker_lock);
1169
1170                 node_free(fn);
1171                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1172                         return pn;
1173
1174                 rt6_release(pn->leaf);
1175                 pn->leaf = NULL;
1176                 fn = pn;
1177         }
1178 }
1179
1180 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1181                            struct nl_info *info)
1182 {
1183         struct fib6_walker_t *w;
1184         struct rt6_info *rt = *rtp;
1185         struct net *net = info->nl_net;
1186
1187         RT6_TRACE("fib6_del_route\n");
1188
1189         /* Unlink it */
1190         *rtp = rt->dst.rt6_next;
1191         rt->rt6i_node = NULL;
1192         net->ipv6.rt6_stats->fib_rt_entries--;
1193         net->ipv6.rt6_stats->fib_discarded_routes++;
1194
1195         /* Reset round-robin state, if necessary */
1196         if (fn->rr_ptr == rt)
1197                 fn->rr_ptr = NULL;
1198
1199         /* Adjust walkers */
1200         read_lock(&fib6_walker_lock);
1201         FOR_WALKERS(w) {
1202                 if (w->state == FWS_C && w->leaf == rt) {
1203                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1204                         w->leaf = rt->dst.rt6_next;
1205                         if (!w->leaf)
1206                                 w->state = FWS_U;
1207                 }
1208         }
1209         read_unlock(&fib6_walker_lock);
1210
1211         rt->dst.rt6_next = NULL;
1212
1213         /* If it was last route, expunge its radix tree node */
1214         if (!fn->leaf) {
1215                 fn->fn_flags &= ~RTN_RTINFO;
1216                 net->ipv6.rt6_stats->fib_route_nodes--;
1217                 fn = fib6_repair_tree(net, fn);
1218         }
1219
1220         if (atomic_read(&rt->rt6i_ref) != 1) {
1221                 /* This route is used as dummy address holder in some split
1222                  * nodes. It is not leaked, but it still holds other resources,
1223                  * which must be released in time. So, scan ascendant nodes
1224                  * and replace dummy references to this route with references
1225                  * to still alive ones.
1226                  */
1227                 while (fn) {
1228                         if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
1229                                 fn->leaf = fib6_find_prefix(net, fn);
1230                                 atomic_inc(&fn->leaf->rt6i_ref);
1231                                 rt6_release(rt);
1232                         }
1233                         fn = fn->parent;
1234                 }
1235                 /* No more references are possible at this point. */
1236                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1237         }
1238
1239         inet6_rt_notify(RTM_DELROUTE, rt, info);
1240         rt6_release(rt);
1241 }
1242
1243 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1244 {
1245         struct net *net = info->nl_net;
1246         struct fib6_node *fn = rt->rt6i_node;
1247         struct rt6_info **rtp;
1248
1249 #if RT6_DEBUG >= 2
1250         if (rt->dst.obsolete>0) {
1251                 WARN_ON(fn != NULL);
1252                 return -ENOENT;
1253         }
1254 #endif
1255         if (!fn || rt == net->ipv6.ip6_null_entry)
1256                 return -ENOENT;
1257
1258         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1259
1260         if (!(rt->rt6i_flags & RTF_CACHE)) {
1261                 struct fib6_node *pn = fn;
1262 #ifdef CONFIG_IPV6_SUBTREES
1263                 /* clones of this route might be in another subtree */
1264                 if (rt->rt6i_src.plen) {
1265                         while (!(pn->fn_flags & RTN_ROOT))
1266                                 pn = pn->parent;
1267                         pn = pn->parent;
1268                 }
1269 #endif
1270                 fib6_prune_clones(info->nl_net, pn, rt);
1271         }
1272
1273         /*
1274          *      Walk the leaf entries looking for ourself
1275          */
1276
1277         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1278                 if (*rtp == rt) {
1279                         fib6_del_route(fn, rtp, info);
1280                         return 0;
1281                 }
1282         }
1283         return -ENOENT;
1284 }
1285
1286 /*
1287  *      Tree traversal function.
1288  *
1289  *      Certainly, it is not interrupt safe.
1290  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1291  *      It means, that we can modify tree during walking
1292  *      and use this function for garbage collection, clone pruning,
1293  *      cleaning tree when a device goes down etc. etc.
1294  *
1295  *      It guarantees that every node will be traversed,
1296  *      and that it will be traversed only once.
1297  *
1298  *      Callback function w->func may return:
1299  *      0 -> continue walking.
1300  *      positive value -> walking is suspended (used by tree dumps,
1301  *      and probably by gc, if it will be split to several slices)
1302  *      negative value -> terminate walking.
1303  *
1304  *      The function itself returns:
1305  *      0   -> walk is complete.
1306  *      >0  -> walk is incomplete (i.e. suspended)
1307  *      <0  -> walk is terminated by an error.
1308  */
1309
1310 static int fib6_walk_continue(struct fib6_walker_t *w)
1311 {
1312         struct fib6_node *fn, *pn;
1313
1314         for (;;) {
1315                 fn = w->node;
1316                 if (!fn)
1317                         return 0;
1318
1319                 if (w->prune && fn != w->root &&
1320                     fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1321                         w->state = FWS_C;
1322                         w->leaf = fn->leaf;
1323                 }
1324                 switch (w->state) {
1325 #ifdef CONFIG_IPV6_SUBTREES
1326                 case FWS_S:
1327                         if (FIB6_SUBTREE(fn)) {
1328                                 w->node = FIB6_SUBTREE(fn);
1329                                 continue;
1330                         }
1331                         w->state = FWS_L;
1332 #endif
1333                 case FWS_L:
1334                         if (fn->left) {
1335                                 w->node = fn->left;
1336                                 w->state = FWS_INIT;
1337                                 continue;
1338                         }
1339                         w->state = FWS_R;
1340                 case FWS_R:
1341                         if (fn->right) {
1342                                 w->node = fn->right;
1343                                 w->state = FWS_INIT;
1344                                 continue;
1345                         }
1346                         w->state = FWS_C;
1347                         w->leaf = fn->leaf;
1348                 case FWS_C:
1349                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1350                                 int err;
1351
1352                                 if (w->count < w->skip) {
1353                                         w->count++;
1354                                         continue;
1355                                 }
1356
1357                                 err = w->func(w);
1358                                 if (err)
1359                                         return err;
1360
1361                                 w->count++;
1362                                 continue;
1363                         }
1364                         w->state = FWS_U;
1365                 case FWS_U:
1366                         if (fn == w->root)
1367                                 return 0;
1368                         pn = fn->parent;
1369                         w->node = pn;
1370 #ifdef CONFIG_IPV6_SUBTREES
1371                         if (FIB6_SUBTREE(pn) == fn) {
1372                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1373                                 w->state = FWS_L;
1374                                 continue;
1375                         }
1376 #endif
1377                         if (pn->left == fn) {
1378                                 w->state = FWS_R;
1379                                 continue;
1380                         }
1381                         if (pn->right == fn) {
1382                                 w->state = FWS_C;
1383                                 w->leaf = w->node->leaf;
1384                                 continue;
1385                         }
1386 #if RT6_DEBUG >= 2
1387                         WARN_ON(1);
1388 #endif
1389                 }
1390         }
1391 }
1392
1393 static int fib6_walk(struct fib6_walker_t *w)
1394 {
1395         int res;
1396
1397         w->state = FWS_INIT;
1398         w->node = w->root;
1399
1400         fib6_walker_link(w);
1401         res = fib6_walk_continue(w);
1402         if (res <= 0)
1403                 fib6_walker_unlink(w);
1404         return res;
1405 }
1406
1407 static int fib6_clean_node(struct fib6_walker_t *w)
1408 {
1409         int res;
1410         struct rt6_info *rt;
1411         struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1412         struct nl_info info = {
1413                 .nl_net = c->net,
1414         };
1415
1416         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1417                 res = c->func(rt, c->arg);
1418                 if (res < 0) {
1419                         w->leaf = rt;
1420                         res = fib6_del(rt, &info);
1421                         if (res) {
1422 #if RT6_DEBUG >= 2
1423                                 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
1424 #endif
1425                                 continue;
1426                         }
1427                         return 0;
1428                 }
1429                 WARN_ON(res != 0);
1430         }
1431         w->leaf = rt;
1432         return 0;
1433 }
1434
1435 /*
1436  *      Convenient frontend to tree walker.
1437  *
1438  *      func is called on each route.
1439  *              It may return -1 -> delete this route.
1440  *                            0  -> continue walking
1441  *
1442  *      prune==1 -> only immediate children of node (certainly,
1443  *      ignoring pure split nodes) will be scanned.
1444  */
1445
1446 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1447                             int (*func)(struct rt6_info *, void *arg),
1448                             int prune, void *arg)
1449 {
1450         struct fib6_cleaner_t c;
1451
1452         c.w.root = root;
1453         c.w.func = fib6_clean_node;
1454         c.w.prune = prune;
1455         c.w.count = 0;
1456         c.w.skip = 0;
1457         c.func = func;
1458         c.arg = arg;
1459         c.net = net;
1460
1461         fib6_walk(&c.w);
1462 }
1463
1464 void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg),
1465                     int prune, void *arg)
1466 {
1467         struct fib6_table *table;
1468         struct hlist_node *node;
1469         struct hlist_head *head;
1470         unsigned int h;
1471
1472         rcu_read_lock();
1473         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1474                 head = &net->ipv6.fib_table_hash[h];
1475                 hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1476                         read_lock_bh(&table->tb6_lock);
1477                         fib6_clean_tree(net, &table->tb6_root,
1478                                         func, prune, arg);
1479                         read_unlock_bh(&table->tb6_lock);
1480                 }
1481         }
1482         rcu_read_unlock();
1483 }
1484 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
1485                     int prune, void *arg)
1486 {
1487         struct fib6_table *table;
1488         struct hlist_node *node;
1489         struct hlist_head *head;
1490         unsigned int h;
1491
1492         rcu_read_lock();
1493         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1494                 head = &net->ipv6.fib_table_hash[h];
1495                 hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1496                         write_lock_bh(&table->tb6_lock);
1497                         fib6_clean_tree(net, &table->tb6_root,
1498                                         func, prune, arg);
1499                         write_unlock_bh(&table->tb6_lock);
1500                 }
1501         }
1502         rcu_read_unlock();
1503 }
1504
1505 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1506 {
1507         if (rt->rt6i_flags & RTF_CACHE) {
1508                 RT6_TRACE("pruning clone %p\n", rt);
1509                 return -1;
1510         }
1511
1512         return 0;
1513 }
1514
1515 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
1516                               struct rt6_info *rt)
1517 {
1518         fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
1519 }
1520
1521 /*
1522  *      Garbage collection
1523  */
1524
1525 static struct fib6_gc_args
1526 {
1527         int                     timeout;
1528         int                     more;
1529 } gc_args;
1530
1531 static int fib6_age(struct rt6_info *rt, void *arg)
1532 {
1533         unsigned long now = jiffies;
1534
1535         /*
1536          *      check addrconf expiration here.
1537          *      Routes are expired even if they are in use.
1538          *
1539          *      Also age clones. Note, that clones are aged out
1540          *      only if they are not in use now.
1541          */
1542
1543         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1544                 if (time_after(now, rt->dst.expires)) {
1545                         RT6_TRACE("expiring %p\n", rt);
1546                         return -1;
1547                 }
1548                 gc_args.more++;
1549         } else if (rt->rt6i_flags & RTF_CACHE) {
1550                 if (atomic_read(&rt->dst.__refcnt) == 0 &&
1551                     time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1552                         RT6_TRACE("aging clone %p\n", rt);
1553                         return -1;
1554                 } else if (rt->rt6i_flags & RTF_GATEWAY) {
1555                         struct neighbour *neigh;
1556                         __u8 neigh_flags = 0;
1557
1558                         neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1559                         if (neigh) {
1560                                 neigh_flags = neigh->flags;
1561                                 neigh_release(neigh);
1562                         }
1563                         if (neigh_flags & NTF_ROUTER) {
1564                                 RT6_TRACE("purging route %p via non-router but gateway\n",
1565                                           rt);
1566                                 return -1;
1567                         }
1568                 }
1569                 gc_args.more++;
1570         }
1571
1572         return 0;
1573 }
1574
1575 static DEFINE_SPINLOCK(fib6_gc_lock);
1576
1577 void fib6_run_gc(unsigned long expires, struct net *net)
1578 {
1579         if (expires != ~0UL) {
1580                 spin_lock_bh(&fib6_gc_lock);
1581                 gc_args.timeout = expires ? (int)expires :
1582                         net->ipv6.sysctl.ip6_rt_gc_interval;
1583         } else {
1584                 if (!spin_trylock_bh(&fib6_gc_lock)) {
1585                         mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1586                         return;
1587                 }
1588                 gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
1589         }
1590
1591         gc_args.more = icmp6_dst_gc();
1592
1593         fib6_clean_all(net, fib6_age, 0, NULL);
1594
1595         if (gc_args.more)
1596                 mod_timer(&net->ipv6.ip6_fib_timer,
1597                           round_jiffies(jiffies
1598                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1599         else
1600                 del_timer(&net->ipv6.ip6_fib_timer);
1601         spin_unlock_bh(&fib6_gc_lock);
1602 }
1603
1604 static void fib6_gc_timer_cb(unsigned long arg)
1605 {
1606         fib6_run_gc(0, (struct net *)arg);
1607 }
1608
1609 static int __net_init fib6_net_init(struct net *net)
1610 {
1611         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1612
1613         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1614
1615         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1616         if (!net->ipv6.rt6_stats)
1617                 goto out_timer;
1618
1619         /* Avoid false sharing : Use at least a full cache line */
1620         size = max_t(size_t, size, L1_CACHE_BYTES);
1621
1622         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1623         if (!net->ipv6.fib_table_hash)
1624                 goto out_rt6_stats;
1625
1626         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1627                                           GFP_KERNEL);
1628         if (!net->ipv6.fib6_main_tbl)
1629                 goto out_fib_table_hash;
1630
1631         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1632         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1633         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1634                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1635
1636 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1637         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1638                                            GFP_KERNEL);
1639         if (!net->ipv6.fib6_local_tbl)
1640                 goto out_fib6_main_tbl;
1641         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1642         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1643         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1644                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1645 #endif
1646         fib6_tables_init(net);
1647
1648         return 0;
1649
1650 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1651 out_fib6_main_tbl:
1652         kfree(net->ipv6.fib6_main_tbl);
1653 #endif
1654 out_fib_table_hash:
1655         kfree(net->ipv6.fib_table_hash);
1656 out_rt6_stats:
1657         kfree(net->ipv6.rt6_stats);
1658 out_timer:
1659         return -ENOMEM;
1660  }
1661
1662 static void fib6_net_exit(struct net *net)
1663 {
1664         rt6_ifdown(net, NULL);
1665         del_timer_sync(&net->ipv6.ip6_fib_timer);
1666
1667 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1668         kfree(net->ipv6.fib6_local_tbl);
1669 #endif
1670         kfree(net->ipv6.fib6_main_tbl);
1671         kfree(net->ipv6.fib_table_hash);
1672         kfree(net->ipv6.rt6_stats);
1673 }
1674
1675 static struct pernet_operations fib6_net_ops = {
1676         .init = fib6_net_init,
1677         .exit = fib6_net_exit,
1678 };
1679
1680 int __init fib6_init(void)
1681 {
1682         int ret = -ENOMEM;
1683
1684         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1685                                            sizeof(struct fib6_node),
1686                                            0, SLAB_HWCACHE_ALIGN,
1687                                            NULL);
1688         if (!fib6_node_kmem)
1689                 goto out;
1690
1691         ret = register_pernet_subsys(&fib6_net_ops);
1692         if (ret)
1693                 goto out_kmem_cache_create;
1694
1695         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1696                               NULL);
1697         if (ret)
1698                 goto out_unregister_subsys;
1699 out:
1700         return ret;
1701
1702 out_unregister_subsys:
1703         unregister_pernet_subsys(&fib6_net_ops);
1704 out_kmem_cache_create:
1705         kmem_cache_destroy(fib6_node_kmem);
1706         goto out;
1707 }
1708
1709 void fib6_gc_cleanup(void)
1710 {
1711         unregister_pernet_subsys(&fib6_net_ops);
1712         kmem_cache_destroy(fib6_node_kmem);
1713 }