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_free_pcpu(struct rt6_info *non_pcpu_rt)
 158 {
 159         int cpu;
 160
 161         if (!non_pcpu_rt->rt6i_pcpu)
 162                 return;
 163
 164         for_each_possible_cpu(cpu) {
 165                 struct rt6_info **ppcpu_rt;
 166                 struct rt6_info *pcpu_rt;
 167
 168                 ppcpu_rt = per_cpu_ptr(non_pcpu_rt->rt6i_pcpu, cpu);
 169                 pcpu_rt = *ppcpu_rt;
 170                 if (pcpu_rt) {
 171                         dst_free(&pcpu_rt->dst);
 172                         *ppcpu_rt = NULL;
 173                 }
 174         }
 175
 176         non_pcpu_rt->rt6i_pcpu = NULL;
 177 }
 178
 179 static void rt6_release(struct rt6_info *rt)
 180 {
 181         if (atomic_dec_and_test(&rt->rt6i_ref)) {
 182                 rt6_free_pcpu(rt);
 183                 dst_free(&rt->dst);
 184         }
 185 }
 186
 187 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 188 {
 189         unsigned int h;
 190
 191         /*
 192          * Initialize table lock at a single place to give lockdep a key,
 193          * tables aren't visible prior to being linked to the list.
 194          */
 195         rwlock_init(&tb->tb6_lock);
 196
 197         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 198
 199         /*
 200          * No protection necessary, this is the only list mutatation
 201          * operation, tables never disappear once they exist.
 202          */
 203         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 204 }
 205
 206 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 207
 208 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 209 {
 210         struct fib6_table *table;
 211
 212         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 213         if (table) {
 214                 table->tb6_id = id;
 215                 table->tb6_root.leaf = net->ipv6.ip6_null_entry;
 216                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 217                 inet_peer_base_init(&table->tb6_peers);
 218         }
 219
 220         return table;
 221 }
 222
 223 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 224 {
 225         struct fib6_table *tb;
 226
 227         if (id == 0)
 228                 id = RT6_TABLE_MAIN;
 229         tb = fib6_get_table(net, id);
 230         if (tb)
 231                 return tb;
 232
 233         tb = fib6_alloc_table(net, id);
 234         if (tb)
 235                 fib6_link_table(net, tb);
 236
 237         return tb;
 238 }
 239
 240 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 241 {
 242         struct fib6_table *tb;
 243         struct hlist_head *head;
 244         unsigned int h;
 245
 246         if (id == 0)
 247                 id = RT6_TABLE_MAIN;
 248         h = id & (FIB6_TABLE_HASHSZ - 1);
 249         rcu_read_lock();
 250         head = &net->ipv6.fib_table_hash[h];
 251         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 252                 if (tb->tb6_id == id) {
 253                         rcu_read_unlock();
 254                         return tb;
 255                 }
 256         }
 257         rcu_read_unlock();
 258
 259         return NULL;
 260 }
 261
 262 static void __net_init fib6_tables_init(struct net *net)
 263 {
 264         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 265         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 266 }
 267 #else
 268
 269 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 270 {
 271         return fib6_get_table(net, id);
 272 }
 273
 274 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 275 {
 276           return net->ipv6.fib6_main_tbl;
 277 }
 278
 279 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 280                                    int flags, pol_lookup_t lookup)
 281 {
 282         return (struct dst_entry *) lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
 283 }
 284
 285 static void __net_init fib6_tables_init(struct net *net)
 286 {
 287         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 288 }
 289
 290 #endif
 291
 292 static int fib6_dump_node(struct fib6_walker *w)
 293 {
 294         int res;
 295         struct rt6_info *rt;
 296
 297         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
 298                 res = rt6_dump_route(rt, w->args);
 299                 if (res < 0) {
 300                         /* Frame is full, suspend walking */
 301                         w->leaf = rt;
 302                         return 1;
 303                 }
 304         }
 305         w->leaf = NULL;
 306         return 0;
 307 }
 308
 309 static void fib6_dump_end(struct netlink_callback *cb)
 310 {
 311         struct fib6_walker *w = (void *)cb->args[2];
 312
 313         if (w) {
 314                 if (cb->args[4]) {
 315                         cb->args[4] = 0;
 316                         fib6_walker_unlink(w);
 317                 }
 318                 cb->args[2] = 0;
 319                 kfree(w);
 320         }
 321         cb->done = (void *)cb->args[3];
 322         cb->args[1] = 3;
 323 }
 324
 325 static int fib6_dump_done(struct netlink_callback *cb)
 326 {
 327         fib6_dump_end(cb);
 328         return cb->done ? cb->done(cb) : 0;
 329 }
 330
 331 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 332                            struct netlink_callback *cb)
 333 {
 334         struct fib6_walker *w;
 335         int res;
 336
 337         w = (void *)cb->args[2];
 338         w->root = &table->tb6_root;
 339
 340         if (cb->args[4] == 0) {
 341                 w->count = 0;
 342                 w->skip = 0;
 343
 344                 read_lock_bh(&table->tb6_lock);
 345                 res = fib6_walk(w);
 346                 read_unlock_bh(&table->tb6_lock);
 347                 if (res > 0) {
 348                         cb->args[4] = 1;
 349                         cb->args[5] = w->root->fn_sernum;
 350                 }
 351         } else {
 352                 if (cb->args[5] != w->root->fn_sernum) {
 353                         /* Begin at the root if the tree changed */
 354                         cb->args[5] = w->root->fn_sernum;
 355                         w->state = FWS_INIT;
 356                         w->node = w->root;
 357                         w->skip = w->count;
 358                 } else
 359                         w->skip = 0;
 360
 361                 read_lock_bh(&table->tb6_lock);
 362                 res = fib6_walk_continue(w);
 363                 read_unlock_bh(&table->tb6_lock);
 364                 if (res <= 0) {
 365                         fib6_walker_unlink(w);
 366                         cb->args[4] = 0;
 367                 }
 368         }
 369
 370         return res;
 371 }
 372
 373 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 374 {
 375         struct net *net = sock_net(skb->sk);
 376         unsigned int h, s_h;
 377         unsigned int e = 0, s_e;
 378         struct rt6_rtnl_dump_arg arg;
 379         struct fib6_walker *w;
 380         struct fib6_table *tb;
 381         struct hlist_head *head;
 382         int res = 0;
 383
 384         s_h = cb->args[0];
 385         s_e = cb->args[1];
 386
 387         w = (void *)cb->args[2];
 388         if (!w) {
 389                 /* New dump:
 390                  *
 391                  * 1. hook callback destructor.
 392                  */
 393                 cb->args[3] = (long)cb->done;
 394                 cb->done = fib6_dump_done;
 395
 396                 /*
 397                  * 2. allocate and initialize walker.
 398                  */
 399                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 400                 if (!w)
 401                         return -ENOMEM;
 402                 w->func = fib6_dump_node;
 403                 cb->args[2] = (long)w;
 404         }
 405
 406         arg.skb = skb;
 407         arg.cb = cb;
 408         arg.net = net;
 409         w->args = &arg;
 410
 411         rcu_read_lock();
 412         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 413                 e = 0;
 414                 head = &net->ipv6.fib_table_hash[h];
 415                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 416                         if (e < s_e)
 417                                 goto next;
 418                         res = fib6_dump_table(tb, skb, cb);
 419                         if (res != 0)
 420                                 goto out;
 421 next:
 422                         e++;
 423                 }
 424         }
 425 out:
 426         rcu_read_unlock();
 427         cb->args[1] = e;
 428         cb->args[0] = h;
 429
 430         res = res < 0 ? res : skb->len;
 431         if (res <= 0)
 432                 fib6_dump_end(cb);
 433         return res;
 434 }
 435
 436 /*
 437  *      Routing Table
 438  *
 439  *      return the appropriate node for a routing tree "add" operation
 440  *      by either creating and inserting or by returning an existing
 441  *      node.
 442  */
 443
 444 static struct fib6_node *fib6_add_1(struct fib6_node *root,
 445                                      struct in6_addr *addr, int plen,
 446                                      int offset, int allow_create,
 447                                      int replace_required, int sernum)
 448 {
 449         struct fib6_node *fn, *in, *ln;
 450         struct fib6_node *pn = NULL;
 451         struct rt6key *key;
 452         int     bit;
 453         __be32  dir = 0;
 454
 455         RT6_TRACE("fib6_add_1\n");
 456
 457         /* insert node in tree */
 458
 459         fn = root;
 460
 461         do {
 462                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
 463
 464                 /*
 465                  *      Prefix match
 466                  */
 467                 if (plen < fn->fn_bit ||
 468                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 469                         if (!allow_create) {
 470                                 if (replace_required) {
 471                                         pr_warn("Can't replace route, no match found\n");
 472                                         return ERR_PTR(-ENOENT);
 473                                 }
 474                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 475                         }
 476                         goto insert_above;
 477                 }
 478
 479                 /*
 480                  *      Exact match ?
 481                  */
 482
 483                 if (plen == fn->fn_bit) {
 484                         /* clean up an intermediate node */
 485                         if (!(fn->fn_flags & RTN_RTINFO)) {
 486                                 rt6_release(fn->leaf);
 487                                 fn->leaf = NULL;
 488                         }
 489
 490                         fn->fn_sernum = sernum;
 491
 492                         return fn;
 493                 }
 494
 495                 /*
 496                  *      We have more bits to go
 497                  */
 498
 499                 /* Try to walk down on tree. */
 500                 fn->fn_sernum = sernum;
 501                 dir = addr_bit_set(addr, fn->fn_bit);
 502                 pn = fn;
 503                 fn = dir ? fn->right : fn->left;
 504         } while (fn);
 505
 506         if (!allow_create) {
 507                 /* We should not create new node because
 508                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 509                  * I assume it is safe to require NLM_F_CREATE when
 510                  * REPLACE flag is used! Later we may want to remove the
 511                  * check for replace_required, because according
 512                  * to netlink specification, NLM_F_CREATE
 513                  * MUST be specified if new route is created.
 514                  * That would keep IPv6 consistent with IPv4
 515                  */
 516                 if (replace_required) {
 517                         pr_warn("Can't replace route, no match found\n");
 518                         return ERR_PTR(-ENOENT);
 519                 }
 520                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 521         }
 522         /*
 523          *      We walked to the bottom of tree.
 524          *      Create new leaf node without children.
 525          */
 526
 527         ln = node_alloc();
 528
 529         if (!ln)
 530                 return ERR_PTR(-ENOMEM);
 531         ln->fn_bit = plen;
 532
 533         ln->parent = pn;
 534         ln->fn_sernum = sernum;
 535
 536         if (dir)
 537                 pn->right = ln;
 538         else
 539                 pn->left  = ln;
 540
 541         return ln;
 542
 543
 544 insert_above:
 545         /*
 546          * split since we don't have a common prefix anymore or
 547          * we have a less significant route.
 548          * we've to insert an intermediate node on the list
 549          * this new node will point to the one we need to create
 550          * and the current
 551          */
 552
 553         pn = fn->parent;
 554
 555         /* find 1st bit in difference between the 2 addrs.
 556
 557            See comment in __ipv6_addr_diff: bit may be an invalid value,
 558            but if it is >= plen, the value is ignored in any case.
 559          */
 560
 561         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 562
 563         /*
 564          *              (intermediate)[in]
 565          *                /        \
 566          *      (new leaf node)[ln] (old node)[fn]
 567          */
 568         if (plen > bit) {
 569                 in = node_alloc();
 570                 ln = node_alloc();
 571
 572                 if (!in || !ln) {
 573                         if (in)
 574                                 node_free(in);
 575                         if (ln)
 576                                 node_free(ln);
 577                         return ERR_PTR(-ENOMEM);
 578                 }
 579
 580                 /*
 581                  * new intermediate node.
 582                  * RTN_RTINFO will
 583                  * be off since that an address that chooses one of
 584                  * the branches would not match less specific routes
 585                  * in the other branch
 586                  */
 587
 588                 in->fn_bit = bit;
 589
 590                 in->parent = pn;
 591                 in->leaf = fn->leaf;
 592                 atomic_inc(&in->leaf->rt6i_ref);
 593
 594                 in->fn_sernum = sernum;
 595
 596                 /* update parent pointer */
 597                 if (dir)
 598                         pn->right = in;
 599                 else
 600                         pn->left  = in;
 601
 602                 ln->fn_bit = plen;
 603
 604                 ln->parent = in;
 605                 fn->parent = in;
 606
 607                 ln->fn_sernum = sernum;
 608
 609                 if (addr_bit_set(addr, bit)) {
 610                         in->right = ln;
 611                         in->left  = fn;
 612                 } else {
 613                         in->left  = ln;
 614                         in->right = fn;
 615                 }
 616         } else { /* plen <= bit */
 617
 618                 /*
 619                  *              (new leaf node)[ln]
 620                  *                /        \
 621                  *           (old node)[fn] NULL
 622                  */
 623
 624                 ln = node_alloc();
 625
 626                 if (!ln)
 627                         return ERR_PTR(-ENOMEM);
 628
 629                 ln->fn_bit = plen;
 630
 631                 ln->parent = pn;
 632
 633                 ln->fn_sernum = sernum;
 634
 635                 if (dir)
 636                         pn->right = ln;
 637                 else
 638                         pn->left  = ln;
 639
 640                 if (addr_bit_set(&key->addr, plen))
 641                         ln->right = fn;
 642                 else
 643                         ln->left  = fn;
 644
 645                 fn->parent = ln;
 646         }
 647         return ln;
 648 }
 649
 650 static bool rt6_qualify_for_ecmp(struct rt6_info *rt)
 651 {
 652         return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
 653                RTF_GATEWAY;
 654 }
 655
 656 static void fib6_copy_metrics(u32 *mp, const struct mx6_config *mxc)
 657 {
 658         int i;
 659
 660         for (i = 0; i < RTAX_MAX; i++) {
 661                 if (test_bit(i, mxc->mx_valid))
 662                         mp[i] = mxc->mx[i];
 663         }
 664 }
 665
 666 static int fib6_commit_metrics(struct dst_entry *dst, struct mx6_config *mxc)
 667 {
 668         if (!mxc->mx)
 669                 return 0;
 670
 671         if (dst->flags & DST_HOST) {
 672                 u32 *mp = dst_metrics_write_ptr(dst);
 673
 674                 if (unlikely(!mp))
 675                         return -ENOMEM;
 676
 677                 fib6_copy_metrics(mp, mxc);
 678         } else {
 679                 dst_init_metrics(dst, mxc->mx, false);
 680
 681                 /* We've stolen mx now. */
 682                 mxc->mx = NULL;
 683         }
 684
 685         return 0;
 686 }
 687
 688 static void fib6_purge_rt(struct rt6_info *rt, struct fib6_node *fn,
 689                           struct net *net)
 690 {
 691         if (atomic_read(&rt->rt6i_ref) != 1) {
 692                 /* This route is used as dummy address holder in some split
 693                  * nodes. It is not leaked, but it still holds other resources,
 694                  * which must be released in time. So, scan ascendant nodes
 695                  * and replace dummy references to this route with references
 696                  * to still alive ones.
 697                  */
 698                 while (fn) {
 699                         if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
 700                                 fn->leaf = fib6_find_prefix(net, fn);
 701                                 atomic_inc(&fn->leaf->rt6i_ref);
 702                                 rt6_release(rt);
 703                         }
 704                         fn = fn->parent;
 705                 }
 706                 /* No more references are possible at this point. */
 707                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
 708         }
 709 }
 710
 711 /*
 712  *      Insert routing information in a node.
 713  */
 714
 715 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 716                             struct nl_info *info, struct mx6_config *mxc)
 717 {
 718         struct rt6_info *iter = NULL;
 719         struct rt6_info **ins;
 720         struct rt6_info **fallback_ins = NULL;
 721         int replace = (info->nlh &&
 722                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 723         int add = (!info->nlh ||
 724                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
 725         int found = 0;
 726         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
 727         int err;
 728
 729         ins = &fn->leaf;
 730
 731         for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
 732                 /*
 733                  *      Search for duplicates
 734                  */
 735
 736                 if (iter->rt6i_metric == rt->rt6i_metric) {
 737                         /*
 738                          *      Same priority level
 739                          */
 740                         if (info->nlh &&
 741                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
 742                                 return -EEXIST;
 743                         if (replace) {
 744                                 if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
 745                                         found++;
 746                                         break;
 747                                 }
 748                                 if (rt_can_ecmp)
 749                                         fallback_ins = fallback_ins ?: ins;
 750                                 goto next_iter;
 751                         }
 752
 753                         if (iter->dst.dev == rt->dst.dev &&
 754                             iter->rt6i_idev == rt->rt6i_idev &&
 755                             ipv6_addr_equal(&iter->rt6i_gateway,
 756                                             &rt->rt6i_gateway)) {
 757                                 if (rt->rt6i_nsiblings)
 758                                         rt->rt6i_nsiblings = 0;
 759                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
 760                                         return -EEXIST;
 761                                 if (!(rt->rt6i_flags & RTF_EXPIRES))
 762                                         rt6_clean_expires(iter);
 763                                 else
 764                                         rt6_set_expires(iter, rt->dst.expires);
 765                                 iter->rt6i_pmtu = rt->rt6i_pmtu;
 766                                 return -EEXIST;
 767                         }
 768                         /* If we have the same destination and the same metric,
 769                          * but not the same gateway, then the route we try to
 770                          * add is sibling to this route, increment our counter
 771                          * of siblings, and later we will add our route to the
 772                          * list.
 773                          * Only static routes (which don't have flag
 774                          * RTF_EXPIRES) are used for ECMPv6.
 775                          *
 776                          * To avoid long list, we only had siblings if the
 777                          * route have a gateway.
 778                          */
 779                         if (rt_can_ecmp &&
 780                             rt6_qualify_for_ecmp(iter))
 781                                 rt->rt6i_nsiblings++;
 782                 }
 783
 784                 if (iter->rt6i_metric > rt->rt6i_metric)
 785                         break;
 786
 787 next_iter:
 788                 ins = &iter->dst.rt6_next;
 789         }
 790
 791         if (fallback_ins && !found) {
 792                 /* No ECMP-able route found, replace first non-ECMP one */
 793                 ins = fallback_ins;
 794                 iter = *ins;
 795                 found++;
 796         }
 797
 798         /* Reset round-robin state, if necessary */
 799         if (ins == &fn->leaf)
 800                 fn->rr_ptr = NULL;
 801
 802         /* Link this route to others same route. */
 803         if (rt->rt6i_nsiblings) {
 804                 unsigned int rt6i_nsiblings;
 805                 struct rt6_info *sibling, *temp_sibling;
 806
 807                 /* Find the first route that have the same metric */
 808                 sibling = fn->leaf;
 809                 while (sibling) {
 810                         if (sibling->rt6i_metric == rt->rt6i_metric &&
 811                             rt6_qualify_for_ecmp(sibling)) {
 812                                 list_add_tail(&rt->rt6i_siblings,
 813                                               &sibling->rt6i_siblings);
 814                                 break;
 815                         }
 816                         sibling = sibling->dst.rt6_next;
 817                 }
 818                 /* For each sibling in the list, increment the counter of
 819                  * siblings. BUG() if counters does not match, list of siblings
 820                  * is broken!
 821                  */
 822                 rt6i_nsiblings = 0;
 823                 list_for_each_entry_safe(sibling, temp_sibling,
 824                                          &rt->rt6i_siblings, rt6i_siblings) {
 825                         sibling->rt6i_nsiblings++;
 826                         BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
 827                         rt6i_nsiblings++;
 828                 }
 829                 BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
 830         }
 831
 832         /*
 833          *      insert node
 834          */
 835         if (!replace) {
 836                 if (!add)
 837                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
 838
 839 add:
 840                 err = fib6_commit_metrics(&rt->dst, mxc);
 841                 if (err)
 842                         return err;
 843
 844                 rt->dst.rt6_next = iter;
 845                 *ins = rt;
 846                 rt->rt6i_node = fn;
 847                 atomic_inc(&rt->rt6i_ref);
 848                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 849                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 850
 851                 if (!(fn->fn_flags & RTN_RTINFO)) {
 852                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 853                         fn->fn_flags |= RTN_RTINFO;
 854                 }
 855
 856         } else {
 857                 int nsiblings;
 858
 859                 if (!found) {
 860                         if (add)
 861                                 goto add;
 862                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
 863                         return -ENOENT;
 864                 }
 865
 866                 err = fib6_commit_metrics(&rt->dst, mxc);
 867                 if (err)
 868                         return err;
 869
 870                 *ins = rt;
 871                 rt->rt6i_node = fn;
 872                 rt->dst.rt6_next = iter->dst.rt6_next;
 873                 atomic_inc(&rt->rt6i_ref);
 874                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 875                 if (!(fn->fn_flags & RTN_RTINFO)) {
 876                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 877                         fn->fn_flags |= RTN_RTINFO;
 878                 }
 879                 nsiblings = iter->rt6i_nsiblings;
 880                 fib6_purge_rt(iter, fn, info->nl_net);
 881                 rt6_release(iter);
 882
 883                 if (nsiblings) {
 884                         /* Replacing an ECMP route, remove all siblings */
 885                         ins = &rt->dst.rt6_next;
 886                         iter = *ins;
 887                         while (iter) {
 888                                 if (rt6_qualify_for_ecmp(iter)) {
 889                                         *ins = iter->dst.rt6_next;
 890                                         fib6_purge_rt(iter, fn, info->nl_net);
 891                                         rt6_release(iter);
 892                                         nsiblings--;
 893                                 } else {
 894                                         ins = &iter->dst.rt6_next;
 895                                 }
 896                                 iter = *ins;
 897                         }
 898                         WARN_ON(nsiblings != 0);
 899                 }
 900         }
 901
 902         return 0;
 903 }
 904
 905 static void fib6_start_gc(struct net *net, struct rt6_info *rt)
 906 {
 907         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 908             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 909                 mod_timer(&net->ipv6.ip6_fib_timer,
 910                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 911 }
 912
 913 void fib6_force_start_gc(struct net *net)
 914 {
 915         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 916                 mod_timer(&net->ipv6.ip6_fib_timer,
 917                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 918 }
 919
 920 /*
 921  *      Add routing information to the routing tree.
 922  *      <destination addr>/<source addr>
 923  *      with source addr info in sub-trees
 924  */
 925
 926 int fib6_add(struct fib6_node *root, struct rt6_info *rt,
 927              struct nl_info *info, struct mx6_config *mxc)
 928 {
 929         struct fib6_node *fn, *pn = NULL;
 930         int err = -ENOMEM;
 931         int allow_create = 1;
 932         int replace_required = 0;
 933         int sernum = fib6_new_sernum(info->nl_net);
 934
 935         if (info->nlh) {
 936                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 937                         allow_create = 0;
 938                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 939                         replace_required = 1;
 940         }
 941         if (!allow_create && !replace_required)
 942                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 943
 944         fn = fib6_add_1(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
 945                         offsetof(struct rt6_info, rt6i_dst), allow_create,
 946                         replace_required, sernum);
 947         if (IS_ERR(fn)) {
 948                 err = PTR_ERR(fn);
 949                 fn = NULL;
 950                 goto out;
 951         }
 952
 953         pn = fn;
 954
 955 #ifdef CONFIG_IPV6_SUBTREES
 956         if (rt->rt6i_src.plen) {
 957                 struct fib6_node *sn;
 958
 959                 if (!fn->subtree) {
 960                         struct fib6_node *sfn;
 961
 962                         /*
 963                          * Create subtree.
 964                          *
 965                          *              fn[main tree]
 966                          *              |
 967                          *              sfn[subtree root]
 968                          *                 \
 969                          *                  sn[new leaf node]
 970                          */
 971
 972                         /* Create subtree root node */
 973                         sfn = node_alloc();
 974                         if (!sfn)
 975                                 goto st_failure;
 976
 977                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 978                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 979                         sfn->fn_flags = RTN_ROOT;
 980                         sfn->fn_sernum = sernum;
 981
 982                         /* Now add the first leaf node to new subtree */
 983
 984                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 985                                         rt->rt6i_src.plen,
 986                                         offsetof(struct rt6_info, rt6i_src),
 987                                         allow_create, replace_required, sernum);
 988
 989                         if (IS_ERR(sn)) {
 990                                 /* If it is failed, discard just allocated
 991                                    root, and then (in st_failure) stale node
 992                                    in main tree.
 993                                  */
 994                                 node_free(sfn);
 995                                 err = PTR_ERR(sn);
 996                                 goto st_failure;
 997                         }
 998
 999                         /* Now link new subtree to main tree */
1000                         sfn->parent = fn;
1001                         fn->subtree = sfn;
1002                 } else {
1003                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
1004                                         rt->rt6i_src.plen,
1005                                         offsetof(struct rt6_info, rt6i_src),
1006                                         allow_create, replace_required, sernum);
1007
1008                         if (IS_ERR(sn)) {
1009                                 err = PTR_ERR(sn);
1010                                 goto st_failure;
1011                         }
1012                 }
1013
1014                 if (!fn->leaf) {
1015                         fn->leaf = rt;
1016                         atomic_inc(&rt->rt6i_ref);
1017                 }
1018                 fn = sn;
1019         }
1020 #endif
1021
1022         err = fib6_add_rt2node(fn, rt, info, mxc);
1023         if (!err) {
1024                 fib6_start_gc(info->nl_net, rt);
1025                 if (!(rt->rt6i_flags & RTF_CACHE))
1026                         fib6_prune_clones(info->nl_net, pn);
1027         }
1028
1029 out:
1030         if (err) {
1031 #ifdef CONFIG_IPV6_SUBTREES
1032                 /*
1033                  * If fib6_add_1 has cleared the old leaf pointer in the
1034                  * super-tree leaf node we have to find a new one for it.
1035                  */
1036                 if (pn != fn && pn->leaf == rt) {
1037                         pn->leaf = NULL;
1038                         atomic_dec(&rt->rt6i_ref);
1039                 }
1040                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
1041                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
1042 #if RT6_DEBUG >= 2
1043                         if (!pn->leaf) {
1044                                 WARN_ON(pn->leaf == NULL);
1045                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
1046                         }
1047 #endif
1048                         atomic_inc(&pn->leaf->rt6i_ref);
1049                 }
1050 #endif
1051                 dst_free(&rt->dst);
1052         }
1053         return err;
1054
1055 #ifdef CONFIG_IPV6_SUBTREES
1056         /* Subtree creation failed, probably main tree node
1057            is orphan. If it is, shoot it.
1058          */
1059 st_failure:
1060         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
1061                 fib6_repair_tree(info->nl_net, fn);
1062         dst_free(&rt->dst);
1063         return err;
1064 #endif
1065 }
1066
1067 /*
1068  *      Routing tree lookup
1069  *
1070  */
1071
1072 struct lookup_args {
1073         int                     offset;         /* key offset on rt6_info       */
1074         const struct in6_addr   *addr;          /* search key                   */
1075 };
1076
1077 static struct fib6_node *fib6_lookup_1(struct fib6_node *root,
1078                                        struct lookup_args *args)
1079 {
1080         struct fib6_node *fn;
1081         __be32 dir;
1082
1083         if (unlikely(args->offset == 0))
1084                 return NULL;
1085
1086         /*
1087          *      Descend on a tree
1088          */
1089
1090         fn = root;
1091
1092         for (;;) {
1093                 struct fib6_node *next;
1094
1095                 dir = addr_bit_set(args->addr, fn->fn_bit);
1096
1097                 next = dir ? fn->right : fn->left;
1098
1099                 if (next) {
1100                         fn = next;
1101                         continue;
1102                 }
1103                 break;
1104         }
1105
1106         while (fn) {
1107                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
1108                         struct rt6key *key;
1109
1110                         key = (struct rt6key *) ((u8 *) fn->leaf +
1111                                                  args->offset);
1112
1113                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1114 #ifdef CONFIG_IPV6_SUBTREES
1115                                 if (fn->subtree) {
1116                                         struct fib6_node *sfn;
1117                                         sfn = fib6_lookup_1(fn->subtree,
1118                                                             args + 1);
1119                                         if (!sfn)
1120                                                 goto backtrack;
1121                                         fn = sfn;
1122                                 }
1123 #endif
1124                                 if (fn->fn_flags & RTN_RTINFO)
1125                                         return fn;
1126                         }
1127                 }
1128 #ifdef CONFIG_IPV6_SUBTREES
1129 backtrack:
1130 #endif
1131                 if (fn->fn_flags & RTN_ROOT)
1132                         break;
1133
1134                 fn = fn->parent;
1135         }
1136
1137         return NULL;
1138 }
1139
1140 struct fib6_node *fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
1141                               const struct in6_addr *saddr)
1142 {
1143         struct fib6_node *fn;
1144         struct lookup_args args[] = {
1145                 {
1146                         .offset = offsetof(struct rt6_info, rt6i_dst),
1147                         .addr = daddr,
1148                 },
1149 #ifdef CONFIG_IPV6_SUBTREES
1150                 {
1151                         .offset = offsetof(struct rt6_info, rt6i_src),
1152                         .addr = saddr,
1153                 },
1154 #endif
1155                 {
1156                         .offset = 0,    /* sentinel */
1157                 }
1158         };
1159
1160         fn = fib6_lookup_1(root, daddr ? args : args + 1);
1161         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1162                 fn = root;
1163
1164         return fn;
1165 }
1166
1167 /*
1168  *      Get node with specified destination prefix (and source prefix,
1169  *      if subtrees are used)
1170  */
1171
1172
1173 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1174                                        const struct in6_addr *addr,
1175                                        int plen, int offset)
1176 {
1177         struct fib6_node *fn;
1178
1179         for (fn = root; fn ; ) {
1180                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1181
1182                 /*
1183                  *      Prefix match
1184                  */
1185                 if (plen < fn->fn_bit ||
1186                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1187                         return NULL;
1188
1189                 if (plen == fn->fn_bit)
1190                         return fn;
1191
1192                 /*
1193                  *      We have more bits to go
1194                  */
1195                 if (addr_bit_set(addr, fn->fn_bit))
1196                         fn = fn->right;
1197                 else
1198                         fn = fn->left;
1199         }
1200         return NULL;
1201 }
1202
1203 struct fib6_node *fib6_locate(struct fib6_node *root,
1204                               const struct in6_addr *daddr, int dst_len,
1205                               const struct in6_addr *saddr, int src_len)
1206 {
1207         struct fib6_node *fn;
1208
1209         fn = fib6_locate_1(root, daddr, dst_len,
1210                            offsetof(struct rt6_info, rt6i_dst));
1211
1212 #ifdef CONFIG_IPV6_SUBTREES
1213         if (src_len) {
1214                 WARN_ON(saddr == NULL);
1215                 if (fn && fn->subtree)
1216                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
1217                                            offsetof(struct rt6_info, rt6i_src));
1218         }
1219 #endif
1220
1221         if (fn && fn->fn_flags & RTN_RTINFO)
1222                 return fn;
1223
1224         return NULL;
1225 }
1226
1227
1228 /*
1229  *      Deletion
1230  *
1231  */
1232
1233 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1234 {
1235         if (fn->fn_flags & RTN_ROOT)
1236                 return net->ipv6.ip6_null_entry;
1237
1238         while (fn) {
1239                 if (fn->left)
1240                         return fn->left->leaf;
1241                 if (fn->right)
1242                         return fn->right->leaf;
1243
1244                 fn = FIB6_SUBTREE(fn);
1245         }
1246         return NULL;
1247 }
1248
1249 /*
1250  *      Called to trim the tree of intermediate nodes when possible. "fn"
1251  *      is the node we want to try and remove.
1252  */
1253
1254 static struct fib6_node *fib6_repair_tree(struct net *net,
1255                                            struct fib6_node *fn)
1256 {
1257         int children;
1258         int nstate;
1259         struct fib6_node *child, *pn;
1260         struct fib6_walker *w;
1261         int iter = 0;
1262
1263         for (;;) {
1264                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1265                 iter++;
1266
1267                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1268                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1269                 WARN_ON(fn->leaf);
1270
1271                 children = 0;
1272                 child = NULL;
1273                 if (fn->right)
1274                         child = fn->right, children |= 1;
1275                 if (fn->left)
1276                         child = fn->left, children |= 2;
1277
1278                 if (children == 3 || FIB6_SUBTREE(fn)
1279 #ifdef CONFIG_IPV6_SUBTREES
1280                     /* Subtree root (i.e. fn) may have one child */
1281                     || (children && fn->fn_flags & RTN_ROOT)
1282 #endif
1283                     ) {
1284                         fn->leaf = fib6_find_prefix(net, fn);
1285 #if RT6_DEBUG >= 2
1286                         if (!fn->leaf) {
1287                                 WARN_ON(!fn->leaf);
1288                                 fn->leaf = net->ipv6.ip6_null_entry;
1289                         }
1290 #endif
1291                         atomic_inc(&fn->leaf->rt6i_ref);
1292                         return fn->parent;
1293                 }
1294
1295                 pn = fn->parent;
1296 #ifdef CONFIG_IPV6_SUBTREES
1297                 if (FIB6_SUBTREE(pn) == fn) {
1298                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1299                         FIB6_SUBTREE(pn) = NULL;
1300                         nstate = FWS_L;
1301                 } else {
1302                         WARN_ON(fn->fn_flags & RTN_ROOT);
1303 #endif
1304                         if (pn->right == fn)
1305                                 pn->right = child;
1306                         else if (pn->left == fn)
1307                                 pn->left = child;
1308 #if RT6_DEBUG >= 2
1309                         else
1310                                 WARN_ON(1);
1311 #endif
1312                         if (child)
1313                                 child->parent = pn;
1314                         nstate = FWS_R;
1315 #ifdef CONFIG_IPV6_SUBTREES
1316                 }
1317 #endif
1318
1319                 read_lock(&fib6_walker_lock);
1320                 FOR_WALKERS(w) {
1321                         if (!child) {
1322                                 if (w->root == fn) {
1323                                         w->root = w->node = NULL;
1324                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1325                                 } else if (w->node == fn) {
1326                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1327                                         w->node = pn;
1328                                         w->state = nstate;
1329                                 }
1330                         } else {
1331                                 if (w->root == fn) {
1332                                         w->root = child;
1333                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1334                                 }
1335                                 if (w->node == fn) {
1336                                         w->node = child;
1337                                         if (children&2) {
1338                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1339                                                 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1340                                         } else {
1341                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1342                                                 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1343                                         }
1344                                 }
1345                         }
1346                 }
1347                 read_unlock(&fib6_walker_lock);
1348
1349                 node_free(fn);
1350                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1351                         return pn;
1352
1353                 rt6_release(pn->leaf);
1354                 pn->leaf = NULL;
1355                 fn = pn;
1356         }
1357 }
1358
1359 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1360                            struct nl_info *info)
1361 {
1362         struct fib6_walker *w;
1363         struct rt6_info *rt = *rtp;
1364         struct net *net = info->nl_net;
1365
1366         RT6_TRACE("fib6_del_route\n");
1367
1368         /* Unlink it */
1369         *rtp = rt->dst.rt6_next;
1370         rt->rt6i_node = NULL;
1371         net->ipv6.rt6_stats->fib_rt_entries--;
1372         net->ipv6.rt6_stats->fib_discarded_routes++;
1373
1374         /* Reset round-robin state, if necessary */
1375         if (fn->rr_ptr == rt)
1376                 fn->rr_ptr = NULL;
1377
1378         /* Remove this entry from other siblings */
1379         if (rt->rt6i_nsiblings) {
1380                 struct rt6_info *sibling, *next_sibling;
1381
1382                 list_for_each_entry_safe(sibling, next_sibling,
1383                                          &rt->rt6i_siblings, rt6i_siblings)
1384                         sibling->rt6i_nsiblings--;
1385                 rt->rt6i_nsiblings = 0;
1386                 list_del_init(&rt->rt6i_siblings);
1387         }
1388
1389         /* Adjust walkers */
1390         read_lock(&fib6_walker_lock);
1391         FOR_WALKERS(w) {
1392                 if (w->state == FWS_C && w->leaf == rt) {
1393                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1394                         w->leaf = rt->dst.rt6_next;
1395                         if (!w->leaf)
1396                                 w->state = FWS_U;
1397                 }
1398         }
1399         read_unlock(&fib6_walker_lock);
1400
1401         rt->dst.rt6_next = NULL;
1402
1403         /* If it was last route, expunge its radix tree node */
1404         if (!fn->leaf) {
1405                 fn->fn_flags &= ~RTN_RTINFO;
1406                 net->ipv6.rt6_stats->fib_route_nodes--;
1407                 fn = fib6_repair_tree(net, fn);
1408         }
1409
1410         fib6_purge_rt(rt, fn, net);
1411
1412         inet6_rt_notify(RTM_DELROUTE, rt, info);
1413         rt6_release(rt);
1414 }
1415
1416 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1417 {
1418         struct net *net = info->nl_net;
1419         struct fib6_node *fn = rt->rt6i_node;
1420         struct rt6_info **rtp;
1421
1422 #if RT6_DEBUG >= 2
1423         if (rt->dst.obsolete > 0) {
1424                 WARN_ON(fn);
1425                 return -ENOENT;
1426         }
1427 #endif
1428         if (!fn || rt == net->ipv6.ip6_null_entry)
1429                 return -ENOENT;
1430
1431         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1432
1433         if (!(rt->rt6i_flags & RTF_CACHE)) {
1434                 struct fib6_node *pn = fn;
1435 #ifdef CONFIG_IPV6_SUBTREES
1436                 /* clones of this route might be in another subtree */
1437                 if (rt->rt6i_src.plen) {
1438                         while (!(pn->fn_flags & RTN_ROOT))
1439                                 pn = pn->parent;
1440                         pn = pn->parent;
1441                 }
1442 #endif
1443                 fib6_prune_clones(info->nl_net, pn);
1444         }
1445
1446         /*
1447          *      Walk the leaf entries looking for ourself
1448          */
1449
1450         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1451                 if (*rtp == rt) {
1452                         fib6_del_route(fn, rtp, info);
1453                         return 0;
1454                 }
1455         }
1456         return -ENOENT;
1457 }
1458
1459 /*
1460  *      Tree traversal function.
1461  *
1462  *      Certainly, it is not interrupt safe.
1463  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1464  *      It means, that we can modify tree during walking
1465  *      and use this function for garbage collection, clone pruning,
1466  *      cleaning tree when a device goes down etc. etc.
1467  *
1468  *      It guarantees that every node will be traversed,
1469  *      and that it will be traversed only once.
1470  *
1471  *      Callback function w->func may return:
1472  *      0 -> continue walking.
1473  *      positive value -> walking is suspended (used by tree dumps,
1474  *      and probably by gc, if it will be split to several slices)
1475  *      negative value -> terminate walking.
1476  *
1477  *      The function itself returns:
1478  *      0   -> walk is complete.
1479  *      >0  -> walk is incomplete (i.e. suspended)
1480  *      <0  -> walk is terminated by an error.
1481  */
1482
1483 static int fib6_walk_continue(struct fib6_walker *w)
1484 {
1485         struct fib6_node *fn, *pn;
1486
1487         for (;;) {
1488                 fn = w->node;
1489                 if (!fn)
1490                         return 0;
1491
1492                 if (w->prune && fn != w->root &&
1493                     fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1494                         w->state = FWS_C;
1495                         w->leaf = fn->leaf;
1496                 }
1497                 switch (w->state) {
1498 #ifdef CONFIG_IPV6_SUBTREES
1499                 case FWS_S:
1500                         if (FIB6_SUBTREE(fn)) {
1501                                 w->node = FIB6_SUBTREE(fn);
1502                                 continue;
1503                         }
1504                         w->state = FWS_L;
1505 #endif
1506                 case FWS_L:
1507                         if (fn->left) {
1508                                 w->node = fn->left;
1509                                 w->state = FWS_INIT;
1510                                 continue;
1511                         }
1512                         w->state = FWS_R;
1513                 case FWS_R:
1514                         if (fn->right) {
1515                                 w->node = fn->right;
1516                                 w->state = FWS_INIT;
1517                                 continue;
1518                         }
1519                         w->state = FWS_C;
1520                         w->leaf = fn->leaf;
1521                 case FWS_C:
1522                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1523                                 int err;
1524
1525                                 if (w->skip) {
1526                                         w->skip--;
1527                                         goto skip;
1528                                 }
1529
1530                                 err = w->func(w);
1531                                 if (err)
1532                                         return err;
1533
1534                                 w->count++;
1535                                 continue;
1536                         }
1537 skip:
1538                         w->state = FWS_U;
1539                 case FWS_U:
1540                         if (fn == w->root)
1541                                 return 0;
1542                         pn = fn->parent;
1543                         w->node = pn;
1544 #ifdef CONFIG_IPV6_SUBTREES
1545                         if (FIB6_SUBTREE(pn) == fn) {
1546                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1547                                 w->state = FWS_L;
1548                                 continue;
1549                         }
1550 #endif
1551                         if (pn->left == fn) {
1552                                 w->state = FWS_R;
1553                                 continue;
1554                         }
1555                         if (pn->right == fn) {
1556                                 w->state = FWS_C;
1557                                 w->leaf = w->node->leaf;
1558                                 continue;
1559                         }
1560 #if RT6_DEBUG >= 2
1561                         WARN_ON(1);
1562 #endif
1563                 }
1564         }
1565 }
1566
1567 static int fib6_walk(struct fib6_walker *w)
1568 {
1569         int res;
1570
1571         w->state = FWS_INIT;
1572         w->node = w->root;
1573
1574         fib6_walker_link(w);
1575         res = fib6_walk_continue(w);
1576         if (res <= 0)
1577                 fib6_walker_unlink(w);
1578         return res;
1579 }
1580
1581 static int fib6_clean_node(struct fib6_walker *w)
1582 {
1583         int res;
1584         struct rt6_info *rt;
1585         struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
1586         struct nl_info info = {
1587                 .nl_net = c->net,
1588         };
1589
1590         if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
1591             w->node->fn_sernum != c->sernum)
1592                 w->node->fn_sernum = c->sernum;
1593
1594         if (!c->func) {
1595                 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
1596                 w->leaf = NULL;
1597                 return 0;
1598         }
1599
1600         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1601                 res = c->func(rt, c->arg);
1602                 if (res < 0) {
1603                         w->leaf = rt;
1604                         res = fib6_del(rt, &info);
1605                         if (res) {
1606 #if RT6_DEBUG >= 2
1607                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1608                                          __func__, rt, rt->rt6i_node, res);
1609 #endif
1610                                 continue;
1611                         }
1612                         return 0;
1613                 }
1614                 WARN_ON(res != 0);
1615         }
1616         w->leaf = rt;
1617         return 0;
1618 }
1619
1620 /*
1621  *      Convenient frontend to tree walker.
1622  *
1623  *      func is called on each route.
1624  *              It may return -1 -> delete this route.
1625  *                            0  -> continue walking
1626  *
1627  *      prune==1 -> only immediate children of node (certainly,
1628  *      ignoring pure split nodes) will be scanned.
1629  */
1630
1631 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1632                             int (*func)(struct rt6_info *, void *arg),
1633                             bool prune, int sernum, void *arg)
1634 {
1635         struct fib6_cleaner c;
1636
1637         c.w.root = root;
1638         c.w.func = fib6_clean_node;
1639         c.w.prune = prune;
1640         c.w.count = 0;
1641         c.w.skip = 0;
1642         c.func = func;
1643         c.sernum = sernum;
1644         c.arg = arg;
1645         c.net = net;
1646
1647         fib6_walk(&c.w);
1648 }
1649
1650 static void __fib6_clean_all(struct net *net,
1651                              int (*func)(struct rt6_info *, void *),
1652                              int sernum, void *arg)
1653 {
1654         struct fib6_table *table;
1655         struct hlist_head *head;
1656         unsigned int h;
1657
1658         rcu_read_lock();
1659         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1660                 head = &net->ipv6.fib_table_hash[h];
1661                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1662                         write_lock_bh(&table->tb6_lock);
1663                         fib6_clean_tree(net, &table->tb6_root,
1664                                         func, false, sernum, arg);
1665                         write_unlock_bh(&table->tb6_lock);
1666                 }
1667         }
1668         rcu_read_unlock();
1669 }
1670
1671 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *),
1672                     void *arg)
1673 {
1674         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
1675 }
1676
1677 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1678 {
1679         if (rt->rt6i_flags & RTF_CACHE) {
1680                 RT6_TRACE("pruning clone %p\n", rt);
1681                 return -1;
1682         }
1683
1684         return 0;
1685 }
1686
1687 static void fib6_prune_clones(struct net *net, struct fib6_node *fn)
1688 {
1689         fib6_clean_tree(net, fn, fib6_prune_clone, true,
1690                         FIB6_NO_SERNUM_CHANGE, NULL);
1691 }
1692
1693 static void fib6_flush_trees(struct net *net)
1694 {
1695         int new_sernum = fib6_new_sernum(net);
1696
1697         __fib6_clean_all(net, NULL, new_sernum, NULL);
1698 }
1699
1700 /*
1701  *      Garbage collection
1702  */
1703
1704 static struct fib6_gc_args
1705 {
1706         int                     timeout;
1707         int                     more;
1708 } gc_args;
1709
1710 static int fib6_age(struct rt6_info *rt, void *arg)
1711 {
1712         unsigned long now = jiffies;
1713
1714         /*
1715          *      check addrconf expiration here.
1716          *      Routes are expired even if they are in use.
1717          *
1718          *      Also age clones. Note, that clones are aged out
1719          *      only if they are not in use now.
1720          */
1721
1722         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1723                 if (time_after(now, rt->dst.expires)) {
1724                         RT6_TRACE("expiring %p\n", rt);
1725                         return -1;
1726                 }
1727                 gc_args.more++;
1728         } else if (rt->rt6i_flags & RTF_CACHE) {
1729                 if (atomic_read(&rt->dst.__refcnt) == 0 &&
1730                     time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1731                         RT6_TRACE("aging clone %p\n", rt);
1732                         return -1;
1733                 } else if (rt->rt6i_flags & RTF_GATEWAY) {
1734                         struct neighbour *neigh;
1735                         __u8 neigh_flags = 0;
1736
1737                         neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1738                         if (neigh) {
1739                                 neigh_flags = neigh->flags;
1740                                 neigh_release(neigh);
1741                         }
1742                         if (!(neigh_flags & NTF_ROUTER)) {
1743                                 RT6_TRACE("purging route %p via non-router but gateway\n",
1744                                           rt);
1745                                 return -1;
1746                         }
1747                 }
1748                 gc_args.more++;
1749         }
1750
1751         return 0;
1752 }
1753
1754 static DEFINE_SPINLOCK(fib6_gc_lock);
1755
1756 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
1757 {
1758         unsigned long now;
1759
1760         if (force) {
1761                 spin_lock_bh(&fib6_gc_lock);
1762         } else if (!spin_trylock_bh(&fib6_gc_lock)) {
1763                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1764                 return;
1765         }
1766         gc_args.timeout = expires ? (int)expires :
1767                           net->ipv6.sysctl.ip6_rt_gc_interval;
1768
1769         gc_args.more = icmp6_dst_gc();
1770
1771         fib6_clean_all(net, fib6_age, NULL);
1772         now = jiffies;
1773         net->ipv6.ip6_rt_last_gc = now;
1774
1775         if (gc_args.more)
1776                 mod_timer(&net->ipv6.ip6_fib_timer,
1777                           round_jiffies(now
1778                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1779         else
1780                 del_timer(&net->ipv6.ip6_fib_timer);
1781         spin_unlock_bh(&fib6_gc_lock);
1782 }
1783
1784 static void fib6_gc_timer_cb(unsigned long arg)
1785 {
1786         fib6_run_gc(0, (struct net *)arg, true);
1787 }
1788
1789 static int __net_init fib6_net_init(struct net *net)
1790 {
1791         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1792
1793         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1794
1795         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1796         if (!net->ipv6.rt6_stats)
1797                 goto out_timer;
1798
1799         /* Avoid false sharing : Use at least a full cache line */
1800         size = max_t(size_t, size, L1_CACHE_BYTES);
1801
1802         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1803         if (!net->ipv6.fib_table_hash)
1804                 goto out_rt6_stats;
1805
1806         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1807                                           GFP_KERNEL);
1808         if (!net->ipv6.fib6_main_tbl)
1809                 goto out_fib_table_hash;
1810
1811         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1812         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1813         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1814                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1815         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1816
1817 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1818         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1819                                            GFP_KERNEL);
1820         if (!net->ipv6.fib6_local_tbl)
1821                 goto out_fib6_main_tbl;
1822         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1823         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1824         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1825                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1826         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1827 #endif
1828         fib6_tables_init(net);
1829
1830         return 0;
1831
1832 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1833 out_fib6_main_tbl:
1834         kfree(net->ipv6.fib6_main_tbl);
1835 #endif
1836 out_fib_table_hash:
1837         kfree(net->ipv6.fib_table_hash);
1838 out_rt6_stats:
1839         kfree(net->ipv6.rt6_stats);
1840 out_timer:
1841         return -ENOMEM;
1842 }
1843
1844 static void fib6_net_exit(struct net *net)
1845 {
1846         rt6_ifdown(net, NULL);
1847         del_timer_sync(&net->ipv6.ip6_fib_timer);
1848
1849 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1850         inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1851         kfree(net->ipv6.fib6_local_tbl);
1852 #endif
1853         inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1854         kfree(net->ipv6.fib6_main_tbl);
1855         kfree(net->ipv6.fib_table_hash);
1856         kfree(net->ipv6.rt6_stats);
1857 }
1858
1859 static struct pernet_operations fib6_net_ops = {
1860         .init = fib6_net_init,
1861         .exit = fib6_net_exit,
1862 };
1863
1864 int __init fib6_init(void)
1865 {
1866         int ret = -ENOMEM;
1867
1868         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1869                                            sizeof(struct fib6_node),
1870                                            0, SLAB_HWCACHE_ALIGN,
1871                                            NULL);
1872         if (!fib6_node_kmem)
1873                 goto out;
1874
1875         ret = register_pernet_subsys(&fib6_net_ops);
1876         if (ret)
1877                 goto out_kmem_cache_create;
1878
1879         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1880                               NULL);
1881         if (ret)
1882                 goto out_unregister_subsys;
1883
1884         __fib6_flush_trees = fib6_flush_trees;
1885 out:
1886         return ret;
1887
1888 out_unregister_subsys:
1889         unregister_pernet_subsys(&fib6_net_ops);
1890 out_kmem_cache_create:
1891         kmem_cache_destroy(fib6_node_kmem);
1892         goto out;
1893 }
1894
1895 void fib6_gc_cleanup(void)
1896 {
1897         unregister_pernet_subsys(&fib6_net_ops);
1898         kmem_cache_destroy(fib6_node_kmem);
1899 }
1900
1901 #ifdef CONFIG_PROC_FS
1902
1903 struct ipv6_route_iter {
1904         struct seq_net_private p;
1905         struct fib6_walker w;
1906         loff_t skip;
1907         struct fib6_table *tbl;
1908         int sernum;
1909 };
1910
1911 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
1912 {
1913         struct rt6_info *rt = v;
1914         struct ipv6_route_iter *iter = seq->private;
1915
1916         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
1917
1918 #ifdef CONFIG_IPV6_SUBTREES
1919         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
1920 #else
1921         seq_puts(seq, "00000000000000000000000000000000 00 ");
1922 #endif
1923         if (rt->rt6i_flags & RTF_GATEWAY)
1924                 seq_printf(seq, "%pi6", &rt->rt6i_gateway);
1925         else
1926                 seq_puts(seq, "00000000000000000000000000000000");
1927
1928         seq_printf(seq, " %08x %08x %08x %08x %8s\n",
1929                    rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
1930                    rt->dst.__use, rt->rt6i_flags,
1931                    rt->dst.dev ? rt->dst.dev->name : "");
1932         iter->w.leaf = NULL;
1933         return 0;
1934 }
1935
1936 static int ipv6_route_yield(struct fib6_walker *w)
1937 {
1938         struct ipv6_route_iter *iter = w->args;
1939
1940         if (!iter->skip)
1941                 return 1;
1942
1943         do {
1944                 iter->w.leaf = iter->w.leaf->dst.rt6_next;
1945                 iter->skip--;
1946                 if (!iter->skip && iter->w.leaf)
1947                         return 1;
1948         } while (iter->w.leaf);
1949
1950         return 0;
1951 }
1952
1953 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter)
1954 {
1955         memset(&iter->w, 0, sizeof(iter->w));
1956         iter->w.func = ipv6_route_yield;
1957         iter->w.root = &iter->tbl->tb6_root;
1958         iter->w.state = FWS_INIT;
1959         iter->w.node = iter->w.root;
1960         iter->w.args = iter;
1961         iter->sernum = iter->w.root->fn_sernum;
1962         INIT_LIST_HEAD(&iter->w.lh);
1963         fib6_walker_link(&iter->w);
1964 }
1965
1966 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
1967                                                     struct net *net)
1968 {
1969         unsigned int h;
1970         struct hlist_node *node;
1971
1972         if (tbl) {
1973                 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
1974                 node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
1975         } else {
1976                 h = 0;
1977                 node = NULL;
1978         }
1979
1980         while (!node && h < FIB6_TABLE_HASHSZ) {
1981                 node = rcu_dereference_bh(
1982                         hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
1983         }
1984         return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
1985 }
1986
1987 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
1988 {
1989         if (iter->sernum != iter->w.root->fn_sernum) {
1990                 iter->sernum = iter->w.root->fn_sernum;
1991                 iter->w.state = FWS_INIT;
1992                 iter->w.node = iter->w.root;
1993                 WARN_ON(iter->w.skip);
1994                 iter->w.skip = iter->w.count;
1995         }
1996 }
1997
1998 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1999 {
2000         int r;
2001         struct rt6_info *n;
2002         struct net *net = seq_file_net(seq);
2003         struct ipv6_route_iter *iter = seq->private;
2004
2005         if (!v)
2006                 goto iter_table;
2007
2008         n = ((struct rt6_info *)v)->dst.rt6_next;
2009         if (n) {
2010                 ++*pos;
2011                 return n;
2012         }
2013
2014 iter_table:
2015         ipv6_route_check_sernum(iter);
2016         read_lock(&iter->tbl->tb6_lock);
2017         r = fib6_walk_continue(&iter->w);
2018         read_unlock(&iter->tbl->tb6_lock);
2019         if (r > 0) {
2020                 if (v)
2021                         ++*pos;
2022                 return iter->w.leaf;
2023         } else if (r < 0) {
2024                 fib6_walker_unlink(&iter->w);
2025                 return NULL;
2026         }
2027         fib6_walker_unlink(&iter->w);
2028
2029         iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
2030         if (!iter->tbl)
2031                 return NULL;
2032
2033         ipv6_route_seq_setup_walk(iter);
2034         goto iter_table;
2035 }
2036
2037 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
2038         __acquires(RCU_BH)
2039 {
2040         struct net *net = seq_file_net(seq);
2041         struct ipv6_route_iter *iter = seq->private;
2042
2043         rcu_read_lock_bh();
2044         iter->tbl = ipv6_route_seq_next_table(NULL, net);
2045         iter->skip = *pos;
2046
2047         if (iter->tbl) {
2048                 ipv6_route_seq_setup_walk(iter);
2049                 return ipv6_route_seq_next(seq, NULL, pos);
2050         } else {
2051                 return NULL;
2052         }
2053 }
2054
2055 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
2056 {
2057         struct fib6_walker *w = &iter->w;
2058         return w->node && !(w->state == FWS_U && w->node == w->root);
2059 }
2060
2061 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2062         __releases(RCU_BH)
2063 {
2064         struct ipv6_route_iter *iter = seq->private;
2065
2066         if (ipv6_route_iter_active(iter))
2067                 fib6_walker_unlink(&iter->w);
2068
2069         rcu_read_unlock_bh();
2070 }
2071
2072 static const struct seq_operations ipv6_route_seq_ops = {
2073         .start  = ipv6_route_seq_start,
2074         .next   = ipv6_route_seq_next,
2075         .stop   = ipv6_route_seq_stop,
2076         .show   = ipv6_route_seq_show
2077 };
2078
2079 int ipv6_route_open(struct inode *inode, struct file *file)
2080 {
2081         return seq_open_net(inode, file, &ipv6_route_seq_ops,
2082                             sizeof(struct ipv6_route_iter));
2083 }
2084
2085 #endif /* CONFIG_PROC_FS */