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