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  *      Changes:
  14  *      Yuji SEKIYA @USAGI:     Support default route on router node;
  15  *                              remove ip6_null_entry from the top of
  16  *                              routing table.
  17  *      Ville Nuorvala:         Fixed routing subtrees.
  18  */
  19
  20 #define pr_fmt(fmt) "IPv6: " fmt
  21
  22 #include <linux/errno.h>
  23 #include <linux/types.h>
  24 #include <linux/net.h>
  25 #include <linux/route.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/in6.h>
  28 #include <linux/init.h>
  29 #include <linux/list.h>
  30 #include <linux/slab.h>
  31
  32 #include <net/ipv6.h>
  33 #include <net/ndisc.h>
  34 #include <net/addrconf.h>
  35
  36 #include <net/ip6_fib.h>
  37 #include <net/ip6_route.h>
  38
  39 #define RT6_DEBUG 2
  40
  41 #if RT6_DEBUG >= 3
  42 #define RT6_TRACE(x...) pr_debug(x)
  43 #else
  44 #define RT6_TRACE(x...) do { ; } while (0)
  45 #endif
  46
  47 static struct kmem_cache *fib6_node_kmem __read_mostly;
  48
  49 struct fib6_cleaner {
  50         struct fib6_walker w;
  51         struct net *net;
  52         int (*func)(struct rt6_info *, void *arg);
  53         int sernum;
  54         void *arg;
  55 };
  56
  57 static DEFINE_RWLOCK(fib6_walker_lock);
  58
  59 #ifdef CONFIG_IPV6_SUBTREES
  60 #define FWS_INIT FWS_S
  61 #else
  62 #define FWS_INIT FWS_L
  63 #endif
  64
  65 static void fib6_prune_clones(struct net *net, struct fib6_node *fn);
  66 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
  67 static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
  68 static int fib6_walk(struct fib6_walker *w);
  69 static int fib6_walk_continue(struct fib6_walker *w);
  70
  71 /*
  72  *      A routing update causes an increase of the serial number on the
  73  *      affected subtree. This allows for cached routes to be asynchronously
  74  *      tested when modifications are made to the destination cache as a
  75  *      result of redirects, path MTU changes, etc.
  76  */
  77
  78 static void fib6_gc_timer_cb(unsigned long arg);
  79
  80 static LIST_HEAD(fib6_walkers);
  81 #define FOR_WALKERS(w) list_for_each_entry(w, &fib6_walkers, lh)
  82
  83 static void fib6_walker_link(struct fib6_walker *w)
  84 {
  85         write_lock_bh(&fib6_walker_lock);
  86         list_add(&w->lh, &fib6_walkers);
  87         write_unlock_bh(&fib6_walker_lock);
  88 }
  89
  90 static void fib6_walker_unlink(struct fib6_walker *w)
  91 {
  92         write_lock_bh(&fib6_walker_lock);
  93         list_del(&w->lh);
  94         write_unlock_bh(&fib6_walker_lock);
  95 }
  96
  97 static int fib6_new_sernum(struct net *net)
  98 {
  99         int new, old;
 100
 101         do {
 102                 old = atomic_read(&net->ipv6.fib6_sernum);
 103                 new = old < INT_MAX ? old + 1 : 1;
 104         } while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
 105                                 old, new) != old);
 106         return new;
 107 }
 108
 109 enum {
 110         FIB6_NO_SERNUM_CHANGE = 0,
 111 };
 112
 113 /*
 114  *      Auxiliary address test functions for the radix tree.
 115  *
 116  *      These assume a 32bit processor (although it will work on
 117  *      64bit processors)
 118  */
 119
 120 /*
 121  *      test bit
 122  */
 123 #if defined(__LITTLE_ENDIAN)
 124 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
 125 #else
 126 # define BITOP_BE32_SWIZZLE     0
 127 #endif
 128
 129 static __be32 addr_bit_set(const void *token, int fn_bit)
 130 {
 131         const __be32 *addr = token;
 132         /*
 133          * Here,
 134          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
 135          * is optimized version of
 136          *      htonl(1 << ((~fn_bit)&0x1F))
 137          * See include/asm-generic/bitops/le.h.
 138          */
 139         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
 140                addr[fn_bit >> 5];
 141 }
 142
 143 static struct fib6_node *node_alloc(void)
 144 {
 145         struct fib6_node *fn;
 146
 147         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 148
 149         return fn;
 150 }
 151
 152 static void node_free(struct fib6_node *fn)
 153 {
 154         kmem_cache_free(fib6_node_kmem, fn);
 155 }
 156
 157 static void rt6_release(struct rt6_info *rt)
 158 {
 159         if (atomic_dec_and_test(&rt->rt6i_ref))
 160                 dst_free(&rt->dst);
 161 }
 162
 163 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 164 {
 165         unsigned int h;
 166
 167         /*
 168          * Initialize table lock at a single place to give lockdep a key,
 169          * tables aren't visible prior to being linked to the list.
 170          */
 171         rwlock_init(&tb->tb6_lock);
 172
 173         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 174
 175         /*
 176          * No protection necessary, this is the only list mutatation
 177          * operation, tables never disappear once they exist.
 178          */
 179         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 180 }
 181
 182 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 183
 184 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 185 {
 186         struct fib6_table *table;
 187
 188         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 189         if (table) {
 190                 table->tb6_id = id;
 191                 table->tb6_root.leaf = net->ipv6.ip6_null_entry;
 192                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 193                 inet_peer_base_init(&table->tb6_peers);
 194         }
 195
 196         return table;
 197 }
 198
 199 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 200 {
 201         struct fib6_table *tb;
 202
 203         if (id == 0)
 204                 id = RT6_TABLE_MAIN;
 205         tb = fib6_get_table(net, id);
 206         if (tb)
 207                 return tb;
 208
 209         tb = fib6_alloc_table(net, id);
 210         if (tb)
 211                 fib6_link_table(net, tb);
 212
 213         return tb;
 214 }
 215
 216 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 217 {
 218         struct fib6_table *tb;
 219         struct hlist_head *head;
 220         unsigned int h;
 221
 222         if (id == 0)
 223                 id = RT6_TABLE_MAIN;
 224         h = id & (FIB6_TABLE_HASHSZ - 1);
 225         rcu_read_lock();
 226         head = &net->ipv6.fib_table_hash[h];
 227         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 228                 if (tb->tb6_id == id) {
 229                         rcu_read_unlock();
 230                         return tb;
 231                 }
 232         }
 233         rcu_read_unlock();
 234
 235         return NULL;
 236 }
 237
 238 static void __net_init fib6_tables_init(struct net *net)
 239 {
 240         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 241         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 242 }
 243 #else
 244
 245 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 246 {
 247         return fib6_get_table(net, id);
 248 }
 249
 250 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 251 {
 252           return net->ipv6.fib6_main_tbl;
 253 }
 254
 255 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 256                                    int flags, pol_lookup_t lookup)
 257 {
 258         return (struct dst_entry *) lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
 259 }
 260
 261 static void __net_init fib6_tables_init(struct net *net)
 262 {
 263         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 264 }
 265
 266 #endif
 267
 268 static int fib6_dump_node(struct fib6_walker *w)
 269 {
 270         int res;
 271         struct rt6_info *rt;
 272
 273         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
 274                 res = rt6_dump_route(rt, w->args);
 275                 if (res < 0) {
 276                         /* Frame is full, suspend walking */
 277                         w->leaf = rt;
 278                         return 1;
 279                 }
 280                 WARN_ON(res == 0);
 281         }
 282         w->leaf = NULL;
 283         return 0;
 284 }
 285
 286 static void fib6_dump_end(struct netlink_callback *cb)
 287 {
 288         struct fib6_walker *w = (void *)cb->args[2];
 289
 290         if (w) {
 291                 if (cb->args[4]) {
 292                         cb->args[4] = 0;
 293                         fib6_walker_unlink(w);
 294                 }
 295                 cb->args[2] = 0;
 296                 kfree(w);
 297         }
 298         cb->done = (void *)cb->args[3];
 299         cb->args[1] = 3;
 300 }
 301
 302 static int fib6_dump_done(struct netlink_callback *cb)
 303 {
 304         fib6_dump_end(cb);
 305         return cb->done ? cb->done(cb) : 0;
 306 }
 307
 308 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 309                            struct netlink_callback *cb)
 310 {
 311         struct fib6_walker *w;
 312         int res;
 313
 314         w = (void *)cb->args[2];
 315         w->root = &table->tb6_root;
 316
 317         if (cb->args[4] == 0) {
 318                 w->count = 0;
 319                 w->skip = 0;
 320
 321                 read_lock_bh(&table->tb6_lock);
 322                 res = fib6_walk(w);
 323                 read_unlock_bh(&table->tb6_lock);
 324                 if (res > 0) {
 325                         cb->args[4] = 1;
 326                         cb->args[5] = w->root->fn_sernum;
 327                 }
 328         } else {
 329                 if (cb->args[5] != w->root->fn_sernum) {
 330                         /* Begin at the root if the tree changed */
 331                         cb->args[5] = w->root->fn_sernum;
 332                         w->state = FWS_INIT;
 333                         w->node = w->root;
 334                         w->skip = w->count;
 335                 } else
 336                         w->skip = 0;
 337
 338                 read_lock_bh(&table->tb6_lock);
 339                 res = fib6_walk_continue(w);
 340                 read_unlock_bh(&table->tb6_lock);
 341                 if (res <= 0) {
 342                         fib6_walker_unlink(w);
 343                         cb->args[4] = 0;
 344                 }
 345         }
 346
 347         return res;
 348 }
 349
 350 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 351 {
 352         struct net *net = sock_net(skb->sk);
 353         unsigned int h, s_h;
 354         unsigned int e = 0, s_e;
 355         struct rt6_rtnl_dump_arg arg;
 356         struct fib6_walker *w;
 357         struct fib6_table *tb;
 358         struct hlist_head *head;
 359         int res = 0;
 360
 361         s_h = cb->args[0];
 362         s_e = cb->args[1];
 363
 364         w = (void *)cb->args[2];
 365         if (!w) {
 366                 /* New dump:
 367                  *
 368                  * 1. hook callback destructor.
 369                  */
 370                 cb->args[3] = (long)cb->done;
 371                 cb->done = fib6_dump_done;
 372
 373                 /*
 374                  * 2. allocate and initialize walker.
 375                  */
 376                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 377                 if (!w)
 378                         return -ENOMEM;
 379                 w->func = fib6_dump_node;
 380                 cb->args[2] = (long)w;
 381         }
 382
 383         arg.skb = skb;
 384         arg.cb = cb;
 385         arg.net = net;
 386         w->args = &arg;
 387
 388         rcu_read_lock();
 389         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 390                 e = 0;
 391                 head = &net->ipv6.fib_table_hash[h];
 392                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 393                         if (e < s_e)
 394                                 goto next;
 395                         res = fib6_dump_table(tb, skb, cb);
 396                         if (res != 0)
 397                                 goto out;
 398 next:
 399                         e++;
 400                 }
 401         }
 402 out:
 403         rcu_read_unlock();
 404         cb->args[1] = e;
 405         cb->args[0] = h;
 406
 407         res = res < 0 ? res : skb->len;
 408         if (res <= 0)
 409                 fib6_dump_end(cb);
 410         return res;
 411 }
 412
 413 /*
 414  *      Routing Table
 415  *
 416  *      return the appropriate node for a routing tree "add" operation
 417  *      by either creating and inserting or by returning an existing
 418  *      node.
 419  */
 420
 421 static struct fib6_node *fib6_add_1(struct fib6_node *root,
 422                                      struct in6_addr *addr, int plen,
 423                                      int offset, int allow_create,
 424                                      int replace_required, int sernum)
 425 {
 426         struct fib6_node *fn, *in, *ln;
 427         struct fib6_node *pn = NULL;
 428         struct rt6key *key;
 429         int     bit;
 430         __be32  dir = 0;
 431
 432         RT6_TRACE("fib6_add_1\n");
 433
 434         /* insert node in tree */
 435
 436         fn = root;
 437
 438         do {
 439                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
 440
 441                 /*
 442                  *      Prefix match
 443                  */
 444                 if (plen < fn->fn_bit ||
 445                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 446                         if (!allow_create) {
 447                                 if (replace_required) {
 448                                         pr_warn("Can't replace route, no match found\n");
 449                                         return ERR_PTR(-ENOENT);
 450                                 }
 451                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 452                         }
 453                         goto insert_above;
 454                 }
 455
 456                 /*
 457                  *      Exact match ?
 458                  */
 459
 460                 if (plen == fn->fn_bit) {
 461                         /* clean up an intermediate node */
 462                         if (!(fn->fn_flags & RTN_RTINFO)) {
 463                                 rt6_release(fn->leaf);
 464                                 fn->leaf = NULL;
 465                         }
 466
 467                         fn->fn_sernum = sernum;
 468
 469                         return fn;
 470                 }
 471
 472                 /*
 473                  *      We have more bits to go
 474                  */
 475
 476                 /* Try to walk down on tree. */
 477                 fn->fn_sernum = sernum;
 478                 dir = addr_bit_set(addr, fn->fn_bit);
 479                 pn = fn;
 480                 fn = dir ? fn->right : fn->left;
 481         } while (fn);
 482
 483         if (!allow_create) {
 484                 /* We should not create new node because
 485                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 486                  * I assume it is safe to require NLM_F_CREATE when
 487                  * REPLACE flag is used! Later we may want to remove the
 488                  * check for replace_required, because according
 489                  * to netlink specification, NLM_F_CREATE
 490                  * MUST be specified if new route is created.
 491                  * That would keep IPv6 consistent with IPv4
 492                  */
 493                 if (replace_required) {
 494                         pr_warn("Can't replace route, no match found\n");
 495                         return ERR_PTR(-ENOENT);
 496                 }
 497                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 498         }
 499         /*
 500          *      We walked to the bottom of tree.
 501          *      Create new leaf node without children.
 502          */
 503
 504         ln = node_alloc();
 505
 506         if (!ln)
 507                 return ERR_PTR(-ENOMEM);
 508         ln->fn_bit = plen;
 509
 510         ln->parent = pn;
 511         ln->fn_sernum = sernum;
 512
 513         if (dir)
 514                 pn->right = ln;
 515         else
 516                 pn->left  = ln;
 517
 518         return ln;
 519
 520
 521 insert_above:
 522         /*
 523          * split since we don't have a common prefix anymore or
 524          * we have a less significant route.
 525          * we've to insert an intermediate node on the list
 526          * this new node will point to the one we need to create
 527          * and the current
 528          */
 529
 530         pn = fn->parent;
 531
 532         /* find 1st bit in difference between the 2 addrs.
 533
 534            See comment in __ipv6_addr_diff: bit may be an invalid value,
 535            but if it is >= plen, the value is ignored in any case.
 536          */
 537
 538         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 539
 540         /*
 541          *              (intermediate)[in]
 542          *                /        \
 543          *      (new leaf node)[ln] (old node)[fn]
 544          */
 545         if (plen > bit) {
 546                 in = node_alloc();
 547                 ln = node_alloc();
 548
 549                 if (!in || !ln) {
 550                         if (in)
 551                                 node_free(in);
 552                         if (ln)
 553                                 node_free(ln);
 554                         return ERR_PTR(-ENOMEM);
 555                 }
 556
 557                 /*
 558                  * new intermediate node.
 559                  * RTN_RTINFO will
 560                  * be off since that an address that chooses one of
 561                  * the branches would not match less specific routes
 562                  * in the other branch
 563                  */
 564
 565                 in->fn_bit = bit;
 566
 567                 in->parent = pn;
 568                 in->leaf = fn->leaf;
 569                 atomic_inc(&in->leaf->rt6i_ref);
 570
 571                 in->fn_sernum = sernum;
 572
 573                 /* update parent pointer */
 574                 if (dir)
 575                         pn->right = in;
 576                 else
 577                         pn->left  = in;
 578
 579                 ln->fn_bit = plen;
 580
 581                 ln->parent = in;
 582                 fn->parent = in;
 583
 584                 ln->fn_sernum = sernum;
 585
 586                 if (addr_bit_set(addr, bit)) {
 587                         in->right = ln;
 588                         in->left  = fn;
 589                 } else {
 590                         in->left  = ln;
 591                         in->right = fn;
 592                 }
 593         } else { /* plen <= bit */
 594
 595                 /*
 596                  *              (new leaf node)[ln]
 597                  *                /        \
 598                  *           (old node)[fn] NULL
 599                  */
 600
 601                 ln = node_alloc();
 602
 603                 if (!ln)
 604                         return ERR_PTR(-ENOMEM);
 605
 606                 ln->fn_bit = plen;
 607
 608                 ln->parent = pn;
 609
 610                 ln->fn_sernum = sernum;
 611
 612                 if (dir)
 613                         pn->right = ln;
 614                 else
 615                         pn->left  = ln;
 616
 617                 if (addr_bit_set(&key->addr, plen))
 618                         ln->right = fn;
 619                 else
 620                         ln->left  = fn;
 621
 622                 fn->parent = ln;
 623         }
 624         return ln;
 625 }
 626
 627 static bool rt6_qualify_for_ecmp(struct rt6_info *rt)
 628 {
 629         return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
 630                RTF_GATEWAY;
 631 }
 632
 633 static int fib6_commit_metrics(struct dst_entry *dst,
 634                                struct nlattr *mx, int mx_len)
 635 {
 636         struct nlattr *nla;
 637         int remaining;
 638         u32 *mp;
 639
 640         if (dst->flags & DST_HOST) {
 641                 mp = dst_metrics_write_ptr(dst);
 642         } else {
 643                 mp = kzalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC);
 644                 if (!mp)
 645                         return -ENOMEM;
 646                 dst_init_metrics(dst, mp, 0);
 647         }
 648
 649         nla_for_each_attr(nla, mx, mx_len, remaining) {
 650                 int type = nla_type(nla);
 651
 652                 if (type) {
 653                         if (type > RTAX_MAX)
 654                                 return -EINVAL;
 655
 656                         mp[type - 1] = nla_get_u32(nla);
 657                 }
 658         }
 659         return 0;
 660 }
 661
 662 /*
 663  *      Insert routing information in a node.
 664  */
 665
 666 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 667                             struct nl_info *info, struct nlattr *mx, int mx_len)
 668 {
 669         struct rt6_info *iter = NULL;
 670         struct rt6_info **ins;
 671         int replace = (info->nlh &&
 672                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 673         int add = (!info->nlh ||
 674                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
 675         int found = 0;
 676         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
 677         int err;
 678
 679         ins = &fn->leaf;
 680
 681         for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
 682                 /*
 683                  *      Search for duplicates
 684                  */
 685
 686                 if (iter->rt6i_metric == rt->rt6i_metric) {
 687                         /*
 688                          *      Same priority level
 689                          */
 690                         if (info->nlh &&
 691                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
 692                                 return -EEXIST;
 693                         if (replace) {
 694                                 found++;
 695                                 break;
 696                         }
 697
 698                         if (iter->dst.dev == rt->dst.dev &&
 699                             iter->rt6i_idev == rt->rt6i_idev &&
 700                             ipv6_addr_equal(&iter->rt6i_gateway,
 701                                             &rt->rt6i_gateway)) {
 702                                 if (rt->rt6i_nsiblings)
 703                                         rt->rt6i_nsiblings = 0;
 704                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
 705                                         return -EEXIST;
 706                                 if (!(rt->rt6i_flags & RTF_EXPIRES))
 707                                         rt6_clean_expires(iter);
 708                                 else
 709                                         rt6_set_expires(iter, rt->dst.expires);
 710                                 return -EEXIST;
 711                         }
 712                         /* If we have the same destination and the same metric,
 713                          * but not the same gateway, then the route we try to
 714                          * add is sibling to this route, increment our counter
 715                          * of siblings, and later we will add our route to the
 716                          * list.
 717                          * Only static routes (which don't have flag
 718                          * RTF_EXPIRES) are used for ECMPv6.
 719                          *
 720                          * To avoid long list, we only had siblings if the
 721                          * route have a gateway.
 722                          */
 723                         if (rt_can_ecmp &&
 724                             rt6_qualify_for_ecmp(iter))
 725                                 rt->rt6i_nsiblings++;
 726                 }
 727
 728                 if (iter->rt6i_metric > rt->rt6i_metric)
 729                         break;
 730
 731                 ins = &iter->dst.rt6_next;
 732         }
 733
 734         /* Reset round-robin state, if necessary */
 735         if (ins == &fn->leaf)
 736                 fn->rr_ptr = NULL;
 737
 738         /* Link this route to others same route. */
 739         if (rt->rt6i_nsiblings) {
 740                 unsigned int rt6i_nsiblings;
 741                 struct rt6_info *sibling, *temp_sibling;
 742
 743                 /* Find the first route that have the same metric */
 744                 sibling = fn->leaf;
 745                 while (sibling) {
 746                         if (sibling->rt6i_metric == rt->rt6i_metric &&
 747                             rt6_qualify_for_ecmp(sibling)) {
 748                                 list_add_tail(&rt->rt6i_siblings,
 749                                               &sibling->rt6i_siblings);
 750                                 break;
 751                         }
 752                         sibling = sibling->dst.rt6_next;
 753                 }
 754                 /* For each sibling in the list, increment the counter of
 755                  * siblings. BUG() if counters does not match, list of siblings
 756                  * is broken!
 757                  */
 758                 rt6i_nsiblings = 0;
 759                 list_for_each_entry_safe(sibling, temp_sibling,
 760                                          &rt->rt6i_siblings, rt6i_siblings) {
 761                         sibling->rt6i_nsiblings++;
 762                         BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
 763                         rt6i_nsiblings++;
 764                 }
 765                 BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
 766         }
 767
 768         /*
 769          *      insert node
 770          */
 771         if (!replace) {
 772                 if (!add)
 773                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
 774
 775 add:
 776                 if (mx) {
 777                         err = fib6_commit_metrics(&rt->dst, mx, mx_len);
 778                         if (err)
 779                                 return err;
 780                 }
 781                 rt->dst.rt6_next = iter;
 782                 *ins = rt;
 783                 rt->rt6i_node = fn;
 784                 atomic_inc(&rt->rt6i_ref);
 785                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 786                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 787
 788                 if (!(fn->fn_flags & RTN_RTINFO)) {
 789                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 790                         fn->fn_flags |= RTN_RTINFO;
 791                 }
 792
 793         } else {
 794                 if (!found) {
 795                         if (add)
 796                                 goto add;
 797                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
 798                         return -ENOENT;
 799                 }
 800                 if (mx) {
 801                         err = fib6_commit_metrics(&rt->dst, mx, mx_len);
 802                         if (err)
 803                                 return err;
 804                 }
 805                 *ins = rt;
 806                 rt->rt6i_node = fn;
 807                 rt->dst.rt6_next = iter->dst.rt6_next;
 808                 atomic_inc(&rt->rt6i_ref);
 809                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 810                 rt6_release(iter);
 811                 if (!(fn->fn_flags & RTN_RTINFO)) {
 812                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 813                         fn->fn_flags |= RTN_RTINFO;
 814                 }
 815         }
 816
 817         return 0;
 818 }
 819
 820 static void fib6_start_gc(struct net *net, struct rt6_info *rt)
 821 {
 822         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 823             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 824                 mod_timer(&net->ipv6.ip6_fib_timer,
 825                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 826 }
 827
 828 void fib6_force_start_gc(struct net *net)
 829 {
 830         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 831                 mod_timer(&net->ipv6.ip6_fib_timer,
 832                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 833 }
 834
 835 /*
 836  *      Add routing information to the routing tree.
 837  *      <destination addr>/<source addr>
 838  *      with source addr info in sub-trees
 839  */
 840
 841 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
 842              struct nlattr *mx, int mx_len)
 843 {
 844         struct fib6_node *fn, *pn = NULL;
 845         int err = -ENOMEM;
 846         int allow_create = 1;
 847         int replace_required = 0;
 848         int sernum = fib6_new_sernum(info->nl_net);
 849
 850         if (info->nlh) {
 851                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 852                         allow_create = 0;
 853                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 854                         replace_required = 1;
 855         }
 856         if (!allow_create && !replace_required)
 857                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 858
 859         fn = fib6_add_1(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
 860                         offsetof(struct rt6_info, rt6i_dst), allow_create,
 861                         replace_required, sernum);
 862         if (IS_ERR(fn)) {
 863                 err = PTR_ERR(fn);
 864                 fn = NULL;
 865                 goto out;
 866         }
 867
 868         pn = fn;
 869
 870 #ifdef CONFIG_IPV6_SUBTREES
 871         if (rt->rt6i_src.plen) {
 872                 struct fib6_node *sn;
 873
 874                 if (!fn->subtree) {
 875                         struct fib6_node *sfn;
 876
 877                         /*
 878                          * Create subtree.
 879                          *
 880                          *              fn[main tree]
 881                          *              |
 882                          *              sfn[subtree root]
 883                          *                 \
 884                          *                  sn[new leaf node]
 885                          */
 886
 887                         /* Create subtree root node */
 888                         sfn = node_alloc();
 889                         if (!sfn)
 890                                 goto st_failure;
 891
 892                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 893                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 894                         sfn->fn_flags = RTN_ROOT;
 895                         sfn->fn_sernum = sernum;
 896
 897                         /* Now add the first leaf node to new subtree */
 898
 899                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 900                                         rt->rt6i_src.plen,
 901                                         offsetof(struct rt6_info, rt6i_src),
 902                                         allow_create, replace_required, sernum);
 903
 904                         if (IS_ERR(sn)) {
 905                                 /* If it is failed, discard just allocated
 906                                    root, and then (in st_failure) stale node
 907                                    in main tree.
 908                                  */
 909                                 node_free(sfn);
 910                                 err = PTR_ERR(sn);
 911                                 goto st_failure;
 912                         }
 913
 914                         /* Now link new subtree to main tree */
 915                         sfn->parent = fn;
 916                         fn->subtree = sfn;
 917                 } else {
 918                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 919                                         rt->rt6i_src.plen,
 920                                         offsetof(struct rt6_info, rt6i_src),
 921                                         allow_create, replace_required, sernum);
 922
 923                         if (IS_ERR(sn)) {
 924                                 err = PTR_ERR(sn);
 925                                 goto st_failure;
 926                         }
 927                 }
 928
 929                 if (!fn->leaf) {
 930                         fn->leaf = rt;
 931                         atomic_inc(&rt->rt6i_ref);
 932                 }
 933                 fn = sn;
 934         }
 935 #endif
 936
 937         err = fib6_add_rt2node(fn, rt, info, mx, mx_len);
 938         if (!err) {
 939                 fib6_start_gc(info->nl_net, rt);
 940                 if (!(rt->rt6i_flags & RTF_CACHE))
 941                         fib6_prune_clones(info->nl_net, pn);
 942         }
 943
 944 out:
 945         if (err) {
 946 #ifdef CONFIG_IPV6_SUBTREES
 947                 /*
 948                  * If fib6_add_1 has cleared the old leaf pointer in the
 949                  * super-tree leaf node we have to find a new one for it.
 950                  */
 951                 if (pn != fn && pn->leaf == rt) {
 952                         pn->leaf = NULL;
 953                         atomic_dec(&rt->rt6i_ref);
 954                 }
 955                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 956                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
 957 #if RT6_DEBUG >= 2
 958                         if (!pn->leaf) {
 959                                 WARN_ON(pn->leaf == NULL);
 960                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 961                         }
 962 #endif
 963                         atomic_inc(&pn->leaf->rt6i_ref);
 964                 }
 965 #endif
 966                 dst_free(&rt->dst);
 967         }
 968         return err;
 969
 970 #ifdef CONFIG_IPV6_SUBTREES
 971         /* Subtree creation failed, probably main tree node
 972            is orphan. If it is, shoot it.
 973          */
 974 st_failure:
 975         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 976                 fib6_repair_tree(info->nl_net, fn);
 977         dst_free(&rt->dst);
 978         return err;
 979 #endif
 980 }
 981
 982 /*
 983  *      Routing tree lookup
 984  *
 985  */
 986
 987 struct lookup_args {
 988         int                     offset;         /* key offset on rt6_info       */
 989         const struct in6_addr   *addr;          /* search key                   */
 990 };
 991
 992 static struct fib6_node *fib6_lookup_1(struct fib6_node *root,
 993                                        struct lookup_args *args)
 994 {
 995         struct fib6_node *fn;
 996         __be32 dir;
 997
 998         if (unlikely(args->offset == 0))
 999                 return NULL;
1000
1001         /*
1002          *      Descend on a tree
1003          */
1004
1005         fn = root;
1006
1007         for (;;) {
1008                 struct fib6_node *next;
1009
1010                 dir = addr_bit_set(args->addr, fn->fn_bit);
1011
1012                 next = dir ? fn->right : fn->left;
1013
1014                 if (next) {
1015                         fn = next;
1016                         continue;
1017                 }
1018                 break;
1019         }
1020
1021         while (fn) {
1022                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
1023                         struct rt6key *key;
1024
1025                         key = (struct rt6key *) ((u8 *) fn->leaf +
1026                                                  args->offset);
1027
1028                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1029 #ifdef CONFIG_IPV6_SUBTREES
1030                                 if (fn->subtree) {
1031                                         struct fib6_node *sfn;
1032                                         sfn = fib6_lookup_1(fn->subtree,
1033                                                             args + 1);
1034                                         if (!sfn)
1035                                                 goto backtrack;
1036                                         fn = sfn;
1037                                 }
1038 #endif
1039                                 if (fn->fn_flags & RTN_RTINFO)
1040                                         return fn;
1041                         }
1042                 }
1043 #ifdef CONFIG_IPV6_SUBTREES
1044 backtrack:
1045 #endif
1046                 if (fn->fn_flags & RTN_ROOT)
1047                         break;
1048
1049                 fn = fn->parent;
1050         }
1051
1052         return NULL;
1053 }
1054
1055 struct fib6_node *fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
1056                               const struct in6_addr *saddr)
1057 {
1058         struct fib6_node *fn;
1059         struct lookup_args args[] = {
1060                 {
1061                         .offset = offsetof(struct rt6_info, rt6i_dst),
1062                         .addr = daddr,
1063                 },
1064 #ifdef CONFIG_IPV6_SUBTREES
1065                 {
1066                         .offset = offsetof(struct rt6_info, rt6i_src),
1067                         .addr = saddr,
1068                 },
1069 #endif
1070                 {
1071                         .offset = 0,    /* sentinel */
1072                 }
1073         };
1074
1075         fn = fib6_lookup_1(root, daddr ? args : args + 1);
1076         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1077                 fn = root;
1078
1079         return fn;
1080 }
1081
1082 /*
1083  *      Get node with specified destination prefix (and source prefix,
1084  *      if subtrees are used)
1085  */
1086
1087
1088 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1089                                        const struct in6_addr *addr,
1090                                        int plen, int offset)
1091 {
1092         struct fib6_node *fn;
1093
1094         for (fn = root; fn ; ) {
1095                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1096
1097                 /*
1098                  *      Prefix match
1099                  */
1100                 if (plen < fn->fn_bit ||
1101                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1102                         return NULL;
1103
1104                 if (plen == fn->fn_bit)
1105                         return fn;
1106
1107                 /*
1108                  *      We have more bits to go
1109                  */
1110                 if (addr_bit_set(addr, fn->fn_bit))
1111                         fn = fn->right;
1112                 else
1113                         fn = fn->left;
1114         }
1115         return NULL;
1116 }
1117
1118 struct fib6_node *fib6_locate(struct fib6_node *root,
1119                               const struct in6_addr *daddr, int dst_len,
1120                               const struct in6_addr *saddr, int src_len)
1121 {
1122         struct fib6_node *fn;
1123
1124         fn = fib6_locate_1(root, daddr, dst_len,
1125                            offsetof(struct rt6_info, rt6i_dst));
1126
1127 #ifdef CONFIG_IPV6_SUBTREES
1128         if (src_len) {
1129                 WARN_ON(saddr == NULL);
1130                 if (fn && fn->subtree)
1131                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
1132                                            offsetof(struct rt6_info, rt6i_src));
1133         }
1134 #endif
1135
1136         if (fn && fn->fn_flags & RTN_RTINFO)
1137                 return fn;
1138
1139         return NULL;
1140 }
1141
1142
1143 /*
1144  *      Deletion
1145  *
1146  */
1147
1148 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1149 {
1150         if (fn->fn_flags & RTN_ROOT)
1151                 return net->ipv6.ip6_null_entry;
1152
1153         while (fn) {
1154                 if (fn->left)
1155                         return fn->left->leaf;
1156                 if (fn->right)
1157                         return fn->right->leaf;
1158
1159                 fn = FIB6_SUBTREE(fn);
1160         }
1161         return NULL;
1162 }
1163
1164 /*
1165  *      Called to trim the tree of intermediate nodes when possible. "fn"
1166  *      is the node we want to try and remove.
1167  */
1168
1169 static struct fib6_node *fib6_repair_tree(struct net *net,
1170                                            struct fib6_node *fn)
1171 {
1172         int children;
1173         int nstate;
1174         struct fib6_node *child, *pn;
1175         struct fib6_walker *w;
1176         int iter = 0;
1177
1178         for (;;) {
1179                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1180                 iter++;
1181
1182                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1183                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1184                 WARN_ON(fn->leaf != NULL);
1185
1186                 children = 0;
1187                 child = NULL;
1188                 if (fn->right)
1189                         child = fn->right, children |= 1;
1190                 if (fn->left)
1191                         child = fn->left, children |= 2;
1192
1193                 if (children == 3 || FIB6_SUBTREE(fn)
1194 #ifdef CONFIG_IPV6_SUBTREES
1195                     /* Subtree root (i.e. fn) may have one child */
1196                     || (children && fn->fn_flags & RTN_ROOT)
1197 #endif
1198                     ) {
1199                         fn->leaf = fib6_find_prefix(net, fn);
1200 #if RT6_DEBUG >= 2
1201                         if (!fn->leaf) {
1202                                 WARN_ON(!fn->leaf);
1203                                 fn->leaf = net->ipv6.ip6_null_entry;
1204                         }
1205 #endif
1206                         atomic_inc(&fn->leaf->rt6i_ref);
1207                         return fn->parent;
1208                 }
1209
1210                 pn = fn->parent;
1211 #ifdef CONFIG_IPV6_SUBTREES
1212                 if (FIB6_SUBTREE(pn) == fn) {
1213                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1214                         FIB6_SUBTREE(pn) = NULL;
1215                         nstate = FWS_L;
1216                 } else {
1217                         WARN_ON(fn->fn_flags & RTN_ROOT);
1218 #endif
1219                         if (pn->right == fn)
1220                                 pn->right = child;
1221                         else if (pn->left == fn)
1222                                 pn->left = child;
1223 #if RT6_DEBUG >= 2
1224                         else
1225                                 WARN_ON(1);
1226 #endif
1227                         if (child)
1228                                 child->parent = pn;
1229                         nstate = FWS_R;
1230 #ifdef CONFIG_IPV6_SUBTREES
1231                 }
1232 #endif
1233
1234                 read_lock(&fib6_walker_lock);
1235                 FOR_WALKERS(w) {
1236                         if (!child) {
1237                                 if (w->root == fn) {
1238                                         w->root = w->node = NULL;
1239                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1240                                 } else if (w->node == fn) {
1241                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1242                                         w->node = pn;
1243                                         w->state = nstate;
1244                                 }
1245                         } else {
1246                                 if (w->root == fn) {
1247                                         w->root = child;
1248                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1249                                 }
1250                                 if (w->node == fn) {
1251                                         w->node = child;
1252                                         if (children&2) {
1253                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1254                                                 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1255                                         } else {
1256                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1257                                                 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1258                                         }
1259                                 }
1260                         }
1261                 }
1262                 read_unlock(&fib6_walker_lock);
1263
1264                 node_free(fn);
1265                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1266                         return pn;
1267
1268                 rt6_release(pn->leaf);
1269                 pn->leaf = NULL;
1270                 fn = pn;
1271         }
1272 }
1273
1274 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1275                            struct nl_info *info)
1276 {
1277         struct fib6_walker *w;
1278         struct rt6_info *rt = *rtp;
1279         struct net *net = info->nl_net;
1280
1281         RT6_TRACE("fib6_del_route\n");
1282
1283         /* Unlink it */
1284         *rtp = rt->dst.rt6_next;
1285         rt->rt6i_node = NULL;
1286         net->ipv6.rt6_stats->fib_rt_entries--;
1287         net->ipv6.rt6_stats->fib_discarded_routes++;
1288
1289         /* Reset round-robin state, if necessary */
1290         if (fn->rr_ptr == rt)
1291                 fn->rr_ptr = NULL;
1292
1293         /* Remove this entry from other siblings */
1294         if (rt->rt6i_nsiblings) {
1295                 struct rt6_info *sibling, *next_sibling;
1296
1297                 list_for_each_entry_safe(sibling, next_sibling,
1298                                          &rt->rt6i_siblings, rt6i_siblings)
1299                         sibling->rt6i_nsiblings--;
1300                 rt->rt6i_nsiblings = 0;
1301                 list_del_init(&rt->rt6i_siblings);
1302         }
1303
1304         /* Adjust walkers */
1305         read_lock(&fib6_walker_lock);
1306         FOR_WALKERS(w) {
1307                 if (w->state == FWS_C && w->leaf == rt) {
1308                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1309                         w->leaf = rt->dst.rt6_next;
1310                         if (!w->leaf)
1311                                 w->state = FWS_U;
1312                 }
1313         }
1314         read_unlock(&fib6_walker_lock);
1315
1316         rt->dst.rt6_next = NULL;
1317
1318         /* If it was last route, expunge its radix tree node */
1319         if (!fn->leaf) {
1320                 fn->fn_flags &= ~RTN_RTINFO;
1321                 net->ipv6.rt6_stats->fib_route_nodes--;
1322                 fn = fib6_repair_tree(net, fn);
1323         }
1324
1325         if (atomic_read(&rt->rt6i_ref) != 1) {
1326                 /* This route is used as dummy address holder in some split
1327                  * nodes. It is not leaked, but it still holds other resources,
1328                  * which must be released in time. So, scan ascendant nodes
1329                  * and replace dummy references to this route with references
1330                  * to still alive ones.
1331                  */
1332                 while (fn) {
1333                         if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
1334                                 fn->leaf = fib6_find_prefix(net, fn);
1335                                 atomic_inc(&fn->leaf->rt6i_ref);
1336                                 rt6_release(rt);
1337                         }
1338                         fn = fn->parent;
1339                 }
1340                 /* No more references are possible at this point. */
1341                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1342         }
1343
1344         inet6_rt_notify(RTM_DELROUTE, rt, info);
1345         rt6_release(rt);
1346 }
1347
1348 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1349 {
1350         struct net *net = info->nl_net;
1351         struct fib6_node *fn = rt->rt6i_node;
1352         struct rt6_info **rtp;
1353
1354 #if RT6_DEBUG >= 2
1355         if (rt->dst.obsolete > 0) {
1356                 WARN_ON(fn != NULL);
1357                 return -ENOENT;
1358         }
1359 #endif
1360         if (!fn || rt == net->ipv6.ip6_null_entry)
1361                 return -ENOENT;
1362
1363         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1364
1365         if (!(rt->rt6i_flags & RTF_CACHE)) {
1366                 struct fib6_node *pn = fn;
1367 #ifdef CONFIG_IPV6_SUBTREES
1368                 /* clones of this route might be in another subtree */
1369                 if (rt->rt6i_src.plen) {
1370                         while (!(pn->fn_flags & RTN_ROOT))
1371                                 pn = pn->parent;
1372                         pn = pn->parent;
1373                 }
1374 #endif
1375                 fib6_prune_clones(info->nl_net, pn);
1376         }
1377
1378         /*
1379          *      Walk the leaf entries looking for ourself
1380          */
1381
1382         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1383                 if (*rtp == rt) {
1384                         fib6_del_route(fn, rtp, info);
1385                         return 0;
1386                 }
1387         }
1388         return -ENOENT;
1389 }
1390
1391 /*
1392  *      Tree traversal function.
1393  *
1394  *      Certainly, it is not interrupt safe.
1395  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1396  *      It means, that we can modify tree during walking
1397  *      and use this function for garbage collection, clone pruning,
1398  *      cleaning tree when a device goes down etc. etc.
1399  *
1400  *      It guarantees that every node will be traversed,
1401  *      and that it will be traversed only once.
1402  *
1403  *      Callback function w->func may return:
1404  *      0 -> continue walking.
1405  *      positive value -> walking is suspended (used by tree dumps,
1406  *      and probably by gc, if it will be split to several slices)
1407  *      negative value -> terminate walking.
1408  *
1409  *      The function itself returns:
1410  *      0   -> walk is complete.
1411  *      >0  -> walk is incomplete (i.e. suspended)
1412  *      <0  -> walk is terminated by an error.
1413  */
1414
1415 static int fib6_walk_continue(struct fib6_walker *w)
1416 {
1417         struct fib6_node *fn, *pn;
1418
1419         for (;;) {
1420                 fn = w->node;
1421                 if (!fn)
1422                         return 0;
1423
1424                 if (w->prune && fn != w->root &&
1425                     fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1426                         w->state = FWS_C;
1427                         w->leaf = fn->leaf;
1428                 }
1429                 switch (w->state) {
1430 #ifdef CONFIG_IPV6_SUBTREES
1431                 case FWS_S:
1432                         if (FIB6_SUBTREE(fn)) {
1433                                 w->node = FIB6_SUBTREE(fn);
1434                                 continue;
1435                         }
1436                         w->state = FWS_L;
1437 #endif
1438                 case FWS_L:
1439                         if (fn->left) {
1440                                 w->node = fn->left;
1441                                 w->state = FWS_INIT;
1442                                 continue;
1443                         }
1444                         w->state = FWS_R;
1445                 case FWS_R:
1446                         if (fn->right) {
1447                                 w->node = fn->right;
1448                                 w->state = FWS_INIT;
1449                                 continue;
1450                         }
1451                         w->state = FWS_C;
1452                         w->leaf = fn->leaf;
1453                 case FWS_C:
1454                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1455                                 int err;
1456
1457                                 if (w->skip) {
1458                                         w->skip--;
1459                                         goto skip;
1460                                 }
1461
1462                                 err = w->func(w);
1463                                 if (err)
1464                                         return err;
1465
1466                                 w->count++;
1467                                 continue;
1468                         }
1469 skip:
1470                         w->state = FWS_U;
1471                 case FWS_U:
1472                         if (fn == w->root)
1473                                 return 0;
1474                         pn = fn->parent;
1475                         w->node = pn;
1476 #ifdef CONFIG_IPV6_SUBTREES
1477                         if (FIB6_SUBTREE(pn) == fn) {
1478                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1479                                 w->state = FWS_L;
1480                                 continue;
1481                         }
1482 #endif
1483                         if (pn->left == fn) {
1484                                 w->state = FWS_R;
1485                                 continue;
1486                         }
1487                         if (pn->right == fn) {
1488                                 w->state = FWS_C;
1489                                 w->leaf = w->node->leaf;
1490                                 continue;
1491                         }
1492 #if RT6_DEBUG >= 2
1493                         WARN_ON(1);
1494 #endif
1495                 }
1496         }
1497 }
1498
1499 static int fib6_walk(struct fib6_walker *w)
1500 {
1501         int res;
1502
1503         w->state = FWS_INIT;
1504         w->node = w->root;
1505
1506         fib6_walker_link(w);
1507         res = fib6_walk_continue(w);
1508         if (res <= 0)
1509                 fib6_walker_unlink(w);
1510         return res;
1511 }
1512
1513 static int fib6_clean_node(struct fib6_walker *w)
1514 {
1515         int res;
1516         struct rt6_info *rt;
1517         struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
1518         struct nl_info info = {
1519                 .nl_net = c->net,
1520         };
1521
1522         if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
1523             w->node->fn_sernum != c->sernum)
1524                 w->node->fn_sernum = c->sernum;
1525
1526         if (!c->func) {
1527                 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
1528                 w->leaf = NULL;
1529                 return 0;
1530         }
1531
1532         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1533                 res = c->func(rt, c->arg);
1534                 if (res < 0) {
1535                         w->leaf = rt;
1536                         res = fib6_del(rt, &info);
1537                         if (res) {
1538 #if RT6_DEBUG >= 2
1539                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1540                                          __func__, rt, rt->rt6i_node, res);
1541 #endif
1542                                 continue;
1543                         }
1544                         return 0;
1545                 }
1546                 WARN_ON(res != 0);
1547         }
1548         w->leaf = rt;
1549         return 0;
1550 }
1551
1552 /*
1553  *      Convenient frontend to tree walker.
1554  *
1555  *      func is called on each route.
1556  *              It may return -1 -> delete this route.
1557  *                            0  -> continue walking
1558  *
1559  *      prune==1 -> only immediate children of node (certainly,
1560  *      ignoring pure split nodes) will be scanned.
1561  */
1562
1563 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1564                             int (*func)(struct rt6_info *, void *arg),
1565                             bool prune, int sernum, void *arg)
1566 {
1567         struct fib6_cleaner c;
1568
1569         c.w.root = root;
1570         c.w.func = fib6_clean_node;
1571         c.w.prune = prune;
1572         c.w.count = 0;
1573         c.w.skip = 0;
1574         c.func = func;
1575         c.sernum = sernum;
1576         c.arg = arg;
1577         c.net = net;
1578
1579         fib6_walk(&c.w);
1580 }
1581
1582 static void __fib6_clean_all(struct net *net,
1583                              int (*func)(struct rt6_info *, void *),
1584                              int sernum, void *arg)
1585 {
1586         struct fib6_table *table;
1587         struct hlist_head *head;
1588         unsigned int h;
1589
1590         rcu_read_lock();
1591         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1592                 head = &net->ipv6.fib_table_hash[h];
1593                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1594                         write_lock_bh(&table->tb6_lock);
1595                         fib6_clean_tree(net, &table->tb6_root,
1596                                         func, false, sernum, arg);
1597                         write_unlock_bh(&table->tb6_lock);
1598                 }
1599         }
1600         rcu_read_unlock();
1601 }
1602
1603 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *),
1604                     void *arg)
1605 {
1606         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
1607 }
1608
1609 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1610 {
1611         if (rt->rt6i_flags & RTF_CACHE) {
1612                 RT6_TRACE("pruning clone %p\n", rt);
1613                 return -1;
1614         }
1615
1616         return 0;
1617 }
1618
1619 static void fib6_prune_clones(struct net *net, struct fib6_node *fn)
1620 {
1621         fib6_clean_tree(net, fn, fib6_prune_clone, true,
1622                         FIB6_NO_SERNUM_CHANGE, NULL);
1623 }
1624
1625 static void fib6_flush_trees(struct net *net)
1626 {
1627         int new_sernum = fib6_new_sernum(net);
1628
1629         __fib6_clean_all(net, NULL, new_sernum, NULL);
1630 }
1631
1632 /*
1633  *      Garbage collection
1634  */
1635
1636 static struct fib6_gc_args
1637 {
1638         int                     timeout;
1639         int                     more;
1640 } gc_args;
1641
1642 static int fib6_age(struct rt6_info *rt, void *arg)
1643 {
1644         unsigned long now = jiffies;
1645
1646         /*
1647          *      check addrconf expiration here.
1648          *      Routes are expired even if they are in use.
1649          *
1650          *      Also age clones. Note, that clones are aged out
1651          *      only if they are not in use now.
1652          */
1653
1654         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1655                 if (time_after(now, rt->dst.expires)) {
1656                         RT6_TRACE("expiring %p\n", rt);
1657                         return -1;
1658                 }
1659                 gc_args.more++;
1660         } else if (rt->rt6i_flags & RTF_CACHE) {
1661                 if (atomic_read(&rt->dst.__refcnt) == 0 &&
1662                     time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1663                         RT6_TRACE("aging clone %p\n", rt);
1664                         return -1;
1665                 } else if (rt->rt6i_flags & RTF_GATEWAY) {
1666                         struct neighbour *neigh;
1667                         __u8 neigh_flags = 0;
1668
1669                         neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1670                         if (neigh) {
1671                                 neigh_flags = neigh->flags;
1672                                 neigh_release(neigh);
1673                         }
1674                         if (!(neigh_flags & NTF_ROUTER)) {
1675                                 RT6_TRACE("purging route %p via non-router but gateway\n",
1676                                           rt);
1677                                 return -1;
1678                         }
1679                 }
1680                 gc_args.more++;
1681         }
1682
1683         return 0;
1684 }
1685
1686 static DEFINE_SPINLOCK(fib6_gc_lock);
1687
1688 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
1689 {
1690         unsigned long now;
1691
1692         if (force) {
1693                 spin_lock_bh(&fib6_gc_lock);
1694         } else if (!spin_trylock_bh(&fib6_gc_lock)) {
1695                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1696                 return;
1697         }
1698         gc_args.timeout = expires ? (int)expires :
1699                           net->ipv6.sysctl.ip6_rt_gc_interval;
1700
1701         gc_args.more = icmp6_dst_gc();
1702
1703         fib6_clean_all(net, fib6_age, NULL);
1704         now = jiffies;
1705         net->ipv6.ip6_rt_last_gc = now;
1706
1707         if (gc_args.more)
1708                 mod_timer(&net->ipv6.ip6_fib_timer,
1709                           round_jiffies(now
1710                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1711         else
1712                 del_timer(&net->ipv6.ip6_fib_timer);
1713         spin_unlock_bh(&fib6_gc_lock);
1714 }
1715
1716 static void fib6_gc_timer_cb(unsigned long arg)
1717 {
1718         fib6_run_gc(0, (struct net *)arg, true);
1719 }
1720
1721 static int __net_init fib6_net_init(struct net *net)
1722 {
1723         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1724
1725         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1726
1727         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1728         if (!net->ipv6.rt6_stats)
1729                 goto out_timer;
1730
1731         /* Avoid false sharing : Use at least a full cache line */
1732         size = max_t(size_t, size, L1_CACHE_BYTES);
1733
1734         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1735         if (!net->ipv6.fib_table_hash)
1736                 goto out_rt6_stats;
1737
1738         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1739                                           GFP_KERNEL);
1740         if (!net->ipv6.fib6_main_tbl)
1741                 goto out_fib_table_hash;
1742
1743         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1744         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1745         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1746                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1747         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1748
1749 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1750         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1751                                            GFP_KERNEL);
1752         if (!net->ipv6.fib6_local_tbl)
1753                 goto out_fib6_main_tbl;
1754         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1755         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1756         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1757                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1758         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1759 #endif
1760         fib6_tables_init(net);
1761
1762         return 0;
1763
1764 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1765 out_fib6_main_tbl:
1766         kfree(net->ipv6.fib6_main_tbl);
1767 #endif
1768 out_fib_table_hash:
1769         kfree(net->ipv6.fib_table_hash);
1770 out_rt6_stats:
1771         kfree(net->ipv6.rt6_stats);
1772 out_timer:
1773         return -ENOMEM;
1774 }
1775
1776 static void fib6_net_exit(struct net *net)
1777 {
1778         rt6_ifdown(net, NULL);
1779         del_timer_sync(&net->ipv6.ip6_fib_timer);
1780
1781 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1782         inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1783         kfree(net->ipv6.fib6_local_tbl);
1784 #endif
1785         inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1786         kfree(net->ipv6.fib6_main_tbl);
1787         kfree(net->ipv6.fib_table_hash);
1788         kfree(net->ipv6.rt6_stats);
1789 }
1790
1791 static struct pernet_operations fib6_net_ops = {
1792         .init = fib6_net_init,
1793         .exit = fib6_net_exit,
1794 };
1795
1796 int __init fib6_init(void)
1797 {
1798         int ret = -ENOMEM;
1799
1800         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1801                                            sizeof(struct fib6_node),
1802                                            0, SLAB_HWCACHE_ALIGN,
1803                                            NULL);
1804         if (!fib6_node_kmem)
1805                 goto out;
1806
1807         ret = register_pernet_subsys(&fib6_net_ops);
1808         if (ret)
1809                 goto out_kmem_cache_create;
1810
1811         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1812                               NULL);
1813         if (ret)
1814                 goto out_unregister_subsys;
1815
1816         __fib6_flush_trees = fib6_flush_trees;
1817 out:
1818         return ret;
1819
1820 out_unregister_subsys:
1821         unregister_pernet_subsys(&fib6_net_ops);
1822 out_kmem_cache_create:
1823         kmem_cache_destroy(fib6_node_kmem);
1824         goto out;
1825 }
1826
1827 void fib6_gc_cleanup(void)
1828 {
1829         unregister_pernet_subsys(&fib6_net_ops);
1830         kmem_cache_destroy(fib6_node_kmem);
1831 }
1832
1833 #ifdef CONFIG_PROC_FS
1834
1835 struct ipv6_route_iter {
1836         struct seq_net_private p;
1837         struct fib6_walker w;
1838         loff_t skip;
1839         struct fib6_table *tbl;
1840         int sernum;
1841 };
1842
1843 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
1844 {
1845         struct rt6_info *rt = v;
1846         struct ipv6_route_iter *iter = seq->private;
1847
1848         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
1849
1850 #ifdef CONFIG_IPV6_SUBTREES
1851         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
1852 #else
1853         seq_puts(seq, "00000000000000000000000000000000 00 ");
1854 #endif
1855         if (rt->rt6i_flags & RTF_GATEWAY)
1856                 seq_printf(seq, "%pi6", &rt->rt6i_gateway);
1857         else
1858                 seq_puts(seq, "00000000000000000000000000000000");
1859
1860         seq_printf(seq, " %08x %08x %08x %08x %8s\n",
1861                    rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
1862                    rt->dst.__use, rt->rt6i_flags,
1863                    rt->dst.dev ? rt->dst.dev->name : "");
1864         iter->w.leaf = NULL;
1865         return 0;
1866 }
1867
1868 static int ipv6_route_yield(struct fib6_walker *w)
1869 {
1870         struct ipv6_route_iter *iter = w->args;
1871
1872         if (!iter->skip)
1873                 return 1;
1874
1875         do {
1876                 iter->w.leaf = iter->w.leaf->dst.rt6_next;
1877                 iter->skip--;
1878                 if (!iter->skip && iter->w.leaf)
1879                         return 1;
1880         } while (iter->w.leaf);
1881
1882         return 0;
1883 }
1884
1885 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter)
1886 {
1887         memset(&iter->w, 0, sizeof(iter->w));
1888         iter->w.func = ipv6_route_yield;
1889         iter->w.root = &iter->tbl->tb6_root;
1890         iter->w.state = FWS_INIT;
1891         iter->w.node = iter->w.root;
1892         iter->w.args = iter;
1893         iter->sernum = iter->w.root->fn_sernum;
1894         INIT_LIST_HEAD(&iter->w.lh);
1895         fib6_walker_link(&iter->w);
1896 }
1897
1898 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
1899                                                     struct net *net)
1900 {
1901         unsigned int h;
1902         struct hlist_node *node;
1903
1904         if (tbl) {
1905                 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
1906                 node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
1907         } else {
1908                 h = 0;
1909                 node = NULL;
1910         }
1911
1912         while (!node && h < FIB6_TABLE_HASHSZ) {
1913                 node = rcu_dereference_bh(
1914                         hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
1915         }
1916         return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
1917 }
1918
1919 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
1920 {
1921         if (iter->sernum != iter->w.root->fn_sernum) {
1922                 iter->sernum = iter->w.root->fn_sernum;
1923                 iter->w.state = FWS_INIT;
1924                 iter->w.node = iter->w.root;
1925                 WARN_ON(iter->w.skip);
1926                 iter->w.skip = iter->w.count;
1927         }
1928 }
1929
1930 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1931 {
1932         int r;
1933         struct rt6_info *n;
1934         struct net *net = seq_file_net(seq);
1935         struct ipv6_route_iter *iter = seq->private;
1936
1937         if (!v)
1938                 goto iter_table;
1939
1940         n = ((struct rt6_info *)v)->dst.rt6_next;
1941         if (n) {
1942                 ++*pos;
1943                 return n;
1944         }
1945
1946 iter_table:
1947         ipv6_route_check_sernum(iter);
1948         read_lock(&iter->tbl->tb6_lock);
1949         r = fib6_walk_continue(&iter->w);
1950         read_unlock(&iter->tbl->tb6_lock);
1951         if (r > 0) {
1952                 if (v)
1953                         ++*pos;
1954                 return iter->w.leaf;
1955         } else if (r < 0) {
1956                 fib6_walker_unlink(&iter->w);
1957                 return NULL;
1958         }
1959         fib6_walker_unlink(&iter->w);
1960
1961         iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
1962         if (!iter->tbl)
1963                 return NULL;
1964
1965         ipv6_route_seq_setup_walk(iter);
1966         goto iter_table;
1967 }
1968
1969 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
1970         __acquires(RCU_BH)
1971 {
1972         struct net *net = seq_file_net(seq);
1973         struct ipv6_route_iter *iter = seq->private;
1974
1975         rcu_read_lock_bh();
1976         iter->tbl = ipv6_route_seq_next_table(NULL, net);
1977         iter->skip = *pos;
1978
1979         if (iter->tbl) {
1980                 ipv6_route_seq_setup_walk(iter);
1981                 return ipv6_route_seq_next(seq, NULL, pos);
1982         } else {
1983                 return NULL;
1984         }
1985 }
1986
1987 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
1988 {
1989         struct fib6_walker *w = &iter->w;
1990         return w->node && !(w->state == FWS_U && w->node == w->root);
1991 }
1992
1993 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
1994         __releases(RCU_BH)
1995 {
1996         struct ipv6_route_iter *iter = seq->private;
1997
1998         if (ipv6_route_iter_active(iter))
1999                 fib6_walker_unlink(&iter->w);
2000
2001         rcu_read_unlock_bh();
2002 }
2003
2004 static const struct seq_operations ipv6_route_seq_ops = {
2005         .start  = ipv6_route_seq_start,
2006         .next   = ipv6_route_seq_next,
2007         .stop   = ipv6_route_seq_stop,
2008         .show   = ipv6_route_seq_show
2009 };
2010
2011 int ipv6_route_open(struct inode *inode, struct file *file)
2012 {
2013         return seq_open_net(inode, file, &ipv6_route_seq_ops,
2014                             sizeof(struct ipv6_route_iter));
2015 }
2016
2017 #endif /* CONFIG_PROC_FS */