net/ipv6/ip6_fib.c

   1 /*
   2  *      Linux INET6 implementation
   3  *      Forwarding Information Database
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  */
  13
  14 /*
  15  *      Changes:
  16  *      Yuji SEKIYA @USAGI:     Support default route on router node;
  17  *                              remove ip6_null_entry from the top of
  18  *                              routing table.
  19  *      Ville Nuorvala:         Fixed routing subtrees.
  20  */
  21
  22 #define pr_fmt(fmt) "IPv6: " fmt
  23
  24 #include <linux/errno.h>
  25 #include <linux/types.h>
  26 #include <linux/net.h>
  27 #include <linux/route.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/in6.h>
  30 #include <linux/init.h>
  31 #include <linux/list.h>
  32 #include <linux/slab.h>
  33
  34 #include <net/ipv6.h>
  35 #include <net/ndisc.h>
  36 #include <net/addrconf.h>
  37
  38 #include <net/ip6_fib.h>
  39 #include <net/ip6_route.h>
  40
  41 #define RT6_DEBUG 2
  42
  43 #if RT6_DEBUG >= 3
  44 #define RT6_TRACE(x...) pr_debug(x)
  45 #else
  46 #define RT6_TRACE(x...) do { ; } while (0)
  47 #endif
  48
  49 static struct kmem_cache * fib6_node_kmem __read_mostly;
  50
  51 enum fib_walk_state_t
  52 {
  53 #ifdef CONFIG_IPV6_SUBTREES
  54         FWS_S,
  55 #endif
  56         FWS_L,
  57         FWS_R,
  58         FWS_C,
  59         FWS_U
  60 };
  61
  62 struct fib6_cleaner_t
  63 {
  64         struct fib6_walker_t w;
  65         struct net *net;
  66         int (*func)(struct rt6_info *, void *arg);
  67         void *arg;
  68 };
  69
  70 static DEFINE_RWLOCK(fib6_walker_lock);
  71
  72 #ifdef CONFIG_IPV6_SUBTREES
  73 #define FWS_INIT FWS_S
  74 #else
  75 #define FWS_INIT FWS_L
  76 #endif
  77
  78 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
  79                               struct rt6_info *rt);
  80 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
  81 static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
  82 static int fib6_walk(struct fib6_walker_t *w);
  83 static int fib6_walk_continue(struct fib6_walker_t *w);
  84
  85 /*
  86  *      A routing update causes an increase of the serial number on the
  87  *      affected subtree. This allows for cached routes to be asynchronously
  88  *      tested when modifications are made to the destination cache as a
  89  *      result of redirects, path MTU changes, etc.
  90  */
  91
  92 static __u32 rt_sernum;
  93
  94 static void fib6_gc_timer_cb(unsigned long arg);
  95
  96 static LIST_HEAD(fib6_walkers);
  97 #define FOR_WALKERS(w) list_for_each_entry(w, &fib6_walkers, lh)
  98
  99 static inline void fib6_walker_link(struct fib6_walker_t *w)
 100 {
 101         write_lock_bh(&fib6_walker_lock);
 102         list_add(&w->lh, &fib6_walkers);
 103         write_unlock_bh(&fib6_walker_lock);
 104 }
 105
 106 static inline void fib6_walker_unlink(struct fib6_walker_t *w)
 107 {
 108         write_lock_bh(&fib6_walker_lock);
 109         list_del(&w->lh);
 110         write_unlock_bh(&fib6_walker_lock);
 111 }
 112 static __inline__ u32 fib6_new_sernum(void)
 113 {
 114         u32 n = ++rt_sernum;
 115         if ((__s32)n <= 0)
 116                 rt_sernum = n = 1;
 117         return n;
 118 }
 119
 120 /*
 121  *      Auxiliary address test functions for the radix tree.
 122  *
 123  *      These assume a 32bit processor (although it will work on
 124  *      64bit processors)
 125  */
 126
 127 /*
 128  *      test bit
 129  */
 130 #if defined(__LITTLE_ENDIAN)
 131 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
 132 #else
 133 # define BITOP_BE32_SWIZZLE     0
 134 #endif
 135
 136 static __inline__ __be32 addr_bit_set(const void *token, int fn_bit)
 137 {
 138         const __be32 *addr = token;
 139         /*
 140          * Here,
 141          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
 142          * is optimized version of
 143          *      htonl(1 << ((~fn_bit)&0x1F))
 144          * See include/asm-generic/bitops/le.h.
 145          */
 146         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
 147                addr[fn_bit >> 5];
 148 }
 149
 150 static __inline__ struct fib6_node * node_alloc(void)
 151 {
 152         struct fib6_node *fn;
 153
 154         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
 155
 156         return fn;
 157 }
 158
 159 static __inline__ void node_free(struct fib6_node * fn)
 160 {
 161         kmem_cache_free(fib6_node_kmem, fn);
 162 }
 163
 164 static __inline__ void rt6_release(struct rt6_info *rt)
 165 {
 166         if (atomic_dec_and_test(&rt->rt6i_ref))
 167                 dst_free(&rt->dst);
 168 }
 169
 170 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 171 {
 172         unsigned int h;
 173
 174         /*
 175          * Initialize table lock at a single place to give lockdep a key,
 176          * tables aren't visible prior to being linked to the list.
 177          */
 178         rwlock_init(&tb->tb6_lock);
 179
 180         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
 181
 182         /*
 183          * No protection necessary, this is the only list mutatation
 184          * operation, tables never disappear once they exist.
 185          */
 186         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
 187 }
 188
 189 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 190
 191 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
 192 {
 193         struct fib6_table *table;
 194
 195         table = kzalloc(sizeof(*table), GFP_ATOMIC);
 196         if (table) {
 197                 table->tb6_id = id;
 198                 table->tb6_root.leaf = net->ipv6.ip6_null_entry;
 199                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
 200                 inet_peer_base_init(&table->tb6_peers);
 201         }
 202
 203         return table;
 204 }
 205
 206 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 207 {
 208         struct fib6_table *tb;
 209
 210         if (id == 0)
 211                 id = RT6_TABLE_MAIN;
 212         tb = fib6_get_table(net, id);
 213         if (tb)
 214                 return tb;
 215
 216         tb = fib6_alloc_table(net, id);
 217         if (tb)
 218                 fib6_link_table(net, tb);
 219
 220         return tb;
 221 }
 222
 223 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 224 {
 225         struct fib6_table *tb;
 226         struct hlist_head *head;
 227         unsigned int h;
 228
 229         if (id == 0)
 230                 id = RT6_TABLE_MAIN;
 231         h = id & (FIB6_TABLE_HASHSZ - 1);
 232         rcu_read_lock();
 233         head = &net->ipv6.fib_table_hash[h];
 234         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 235                 if (tb->tb6_id == id) {
 236                         rcu_read_unlock();
 237                         return tb;
 238                 }
 239         }
 240         rcu_read_unlock();
 241
 242         return NULL;
 243 }
 244
 245 static void __net_init fib6_tables_init(struct net *net)
 246 {
 247         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 248         fib6_link_table(net, net->ipv6.fib6_local_tbl);
 249 }
 250 #else
 251
 252 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 253 {
 254         return fib6_get_table(net, id);
 255 }
 256
 257 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 258 {
 259           return net->ipv6.fib6_main_tbl;
 260 }
 261
 262 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 263                                    int flags, pol_lookup_t lookup)
 264 {
 265         return (struct dst_entry *) lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
 266 }
 267
 268 static void __net_init fib6_tables_init(struct net *net)
 269 {
 270         fib6_link_table(net, net->ipv6.fib6_main_tbl);
 271 }
 272
 273 #endif
 274
 275 static int fib6_dump_node(struct fib6_walker_t *w)
 276 {
 277         int res;
 278         struct rt6_info *rt;
 279
 280         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
 281                 res = rt6_dump_route(rt, w->args);
 282                 if (res < 0) {
 283                         /* Frame is full, suspend walking */
 284                         w->leaf = rt;
 285                         return 1;
 286                 }
 287                 WARN_ON(res == 0);
 288         }
 289         w->leaf = NULL;
 290         return 0;
 291 }
 292
 293 static void fib6_dump_end(struct netlink_callback *cb)
 294 {
 295         struct fib6_walker_t *w = (void*)cb->args[2];
 296
 297         if (w) {
 298                 if (cb->args[4]) {
 299                         cb->args[4] = 0;
 300                         fib6_walker_unlink(w);
 301                 }
 302                 cb->args[2] = 0;
 303                 kfree(w);
 304         }
 305         cb->done = (void*)cb->args[3];
 306         cb->args[1] = 3;
 307 }
 308
 309 static int fib6_dump_done(struct netlink_callback *cb)
 310 {
 311         fib6_dump_end(cb);
 312         return cb->done ? cb->done(cb) : 0;
 313 }
 314
 315 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 316                            struct netlink_callback *cb)
 317 {
 318         struct fib6_walker_t *w;
 319         int res;
 320
 321         w = (void *)cb->args[2];
 322         w->root = &table->tb6_root;
 323
 324         if (cb->args[4] == 0) {
 325                 w->count = 0;
 326                 w->skip = 0;
 327
 328                 read_lock_bh(&table->tb6_lock);
 329                 res = fib6_walk(w);
 330                 read_unlock_bh(&table->tb6_lock);
 331                 if (res > 0) {
 332                         cb->args[4] = 1;
 333                         cb->args[5] = w->root->fn_sernum;
 334                 }
 335         } else {
 336                 if (cb->args[5] != w->root->fn_sernum) {
 337                         /* Begin at the root if the tree changed */
 338                         cb->args[5] = w->root->fn_sernum;
 339                         w->state = FWS_INIT;
 340                         w->node = w->root;
 341                         w->skip = w->count;
 342                 } else
 343                         w->skip = 0;
 344
 345                 read_lock_bh(&table->tb6_lock);
 346                 res = fib6_walk_continue(w);
 347                 read_unlock_bh(&table->tb6_lock);
 348                 if (res <= 0) {
 349                         fib6_walker_unlink(w);
 350                         cb->args[4] = 0;
 351                 }
 352         }
 353
 354         return res;
 355 }
 356
 357 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 358 {
 359         struct net *net = sock_net(skb->sk);
 360         unsigned int h, s_h;
 361         unsigned int e = 0, s_e;
 362         struct rt6_rtnl_dump_arg arg;
 363         struct fib6_walker_t *w;
 364         struct fib6_table *tb;
 365         struct hlist_head *head;
 366         int res = 0;
 367
 368         s_h = cb->args[0];
 369         s_e = cb->args[1];
 370
 371         w = (void *)cb->args[2];
 372         if (!w) {
 373                 /* New dump:
 374                  *
 375                  * 1. hook callback destructor.
 376                  */
 377                 cb->args[3] = (long)cb->done;
 378                 cb->done = fib6_dump_done;
 379
 380                 /*
 381                  * 2. allocate and initialize walker.
 382                  */
 383                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 384                 if (!w)
 385                         return -ENOMEM;
 386                 w->func = fib6_dump_node;
 387                 cb->args[2] = (long)w;
 388         }
 389
 390         arg.skb = skb;
 391         arg.cb = cb;
 392         arg.net = net;
 393         w->args = &arg;
 394
 395         rcu_read_lock();
 396         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 397                 e = 0;
 398                 head = &net->ipv6.fib_table_hash[h];
 399                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 400                         if (e < s_e)
 401                                 goto next;
 402                         res = fib6_dump_table(tb, skb, cb);
 403                         if (res != 0)
 404                                 goto out;
 405 next:
 406                         e++;
 407                 }
 408         }
 409 out:
 410         rcu_read_unlock();
 411         cb->args[1] = e;
 412         cb->args[0] = h;
 413
 414         res = res < 0 ? res : skb->len;
 415         if (res <= 0)
 416                 fib6_dump_end(cb);
 417         return res;
 418 }
 419
 420 /*
 421  *      Routing Table
 422  *
 423  *      return the appropriate node for a routing tree "add" operation
 424  *      by either creating and inserting or by returning an existing
 425  *      node.
 426  */
 427
 428 static struct fib6_node *fib6_add_1(struct fib6_node *root,
 429                                      struct in6_addr *addr, int plen,
 430                                      int offset, int allow_create,
 431                                      int replace_required)
 432 {
 433         struct fib6_node *fn, *in, *ln;
 434         struct fib6_node *pn = NULL;
 435         struct rt6key *key;
 436         int     bit;
 437         __be32  dir = 0;
 438         __u32   sernum = fib6_new_sernum();
 439
 440         RT6_TRACE("fib6_add_1\n");
 441
 442         /* insert node in tree */
 443
 444         fn = root;
 445
 446         do {
 447                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
 448
 449                 /*
 450                  *      Prefix match
 451                  */
 452                 if (plen < fn->fn_bit ||
 453                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 454                         if (!allow_create) {
 455                                 if (replace_required) {
 456                                         pr_warn("Can't replace route, no match found\n");
 457                                         return ERR_PTR(-ENOENT);
 458                                 }
 459                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 460                         }
 461                         goto insert_above;
 462                 }
 463
 464                 /*
 465                  *      Exact match ?
 466                  */
 467
 468                 if (plen == fn->fn_bit) {
 469                         /* clean up an intermediate node */
 470                         if (!(fn->fn_flags & RTN_RTINFO)) {
 471                                 rt6_release(fn->leaf);
 472                                 fn->leaf = NULL;
 473                         }
 474
 475                         fn->fn_sernum = sernum;
 476
 477                         return fn;
 478                 }
 479
 480                 /*
 481                  *      We have more bits to go
 482                  */
 483
 484                 /* Try to walk down on tree. */
 485                 fn->fn_sernum = sernum;
 486                 dir = addr_bit_set(addr, fn->fn_bit);
 487                 pn = fn;
 488                 fn = dir ? fn->right: fn->left;
 489         } while (fn);
 490
 491         if (!allow_create) {
 492                 /* We should not create new node because
 493                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 494                  * I assume it is safe to require NLM_F_CREATE when
 495                  * REPLACE flag is used! Later we may want to remove the
 496                  * check for replace_required, because according
 497                  * to netlink specification, NLM_F_CREATE
 498                  * MUST be specified if new route is created.
 499                  * That would keep IPv6 consistent with IPv4
 500                  */
 501                 if (replace_required) {
 502                         pr_warn("Can't replace route, no match found\n");
 503                         return ERR_PTR(-ENOENT);
 504                 }
 505                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 506         }
 507         /*
 508          *      We walked to the bottom of tree.
 509          *      Create new leaf node without children.
 510          */
 511
 512         ln = node_alloc();
 513
 514         if (!ln)
 515                 return ERR_PTR(-ENOMEM);
 516         ln->fn_bit = plen;
 517
 518         ln->parent = pn;
 519         ln->fn_sernum = sernum;
 520
 521         if (dir)
 522                 pn->right = ln;
 523         else
 524                 pn->left  = ln;
 525
 526         return ln;
 527
 528
 529 insert_above:
 530         /*
 531          * split since we don't have a common prefix anymore or
 532          * we have a less significant route.
 533          * we've to insert an intermediate node on the list
 534          * this new node will point to the one we need to create
 535          * and the current
 536          */
 537
 538         pn = fn->parent;
 539
 540         /* find 1st bit in difference between the 2 addrs.
 541
 542            See comment in __ipv6_addr_diff: bit may be an invalid value,
 543            but if it is >= plen, the value is ignored in any case.
 544          */
 545
 546         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 547
 548         /*
 549          *              (intermediate)[in]
 550          *                /        \
 551          *      (new leaf node)[ln] (old node)[fn]
 552          */
 553         if (plen > bit) {
 554                 in = node_alloc();
 555                 ln = node_alloc();
 556
 557                 if (!in || !ln) {
 558                         if (in)
 559                                 node_free(in);
 560                         if (ln)
 561                                 node_free(ln);
 562                         return ERR_PTR(-ENOMEM);
 563                 }
 564
 565                 /*
 566                  * new intermediate node.
 567                  * RTN_RTINFO will
 568                  * be off since that an address that chooses one of
 569                  * the branches would not match less specific routes
 570                  * in the other branch
 571                  */
 572
 573                 in->fn_bit = bit;
 574
 575                 in->parent = pn;
 576                 in->leaf = fn->leaf;
 577                 atomic_inc(&in->leaf->rt6i_ref);
 578
 579                 in->fn_sernum = sernum;
 580
 581                 /* update parent pointer */
 582                 if (dir)
 583                         pn->right = in;
 584                 else
 585                         pn->left  = in;
 586
 587                 ln->fn_bit = plen;
 588
 589                 ln->parent = in;
 590                 fn->parent = in;
 591
 592                 ln->fn_sernum = sernum;
 593
 594                 if (addr_bit_set(addr, bit)) {
 595                         in->right = ln;
 596                         in->left  = fn;
 597                 } else {
 598                         in->left  = ln;
 599                         in->right = fn;
 600                 }
 601         } else { /* plen <= bit */
 602
 603                 /*
 604                  *              (new leaf node)[ln]
 605                  *                /        \
 606                  *           (old node)[fn] NULL
 607                  */
 608
 609                 ln = node_alloc();
 610
 611                 if (!ln)
 612                         return ERR_PTR(-ENOMEM);
 613
 614                 ln->fn_bit = plen;
 615
 616                 ln->parent = pn;
 617
 618                 ln->fn_sernum = sernum;
 619
 620                 if (dir)
 621                         pn->right = ln;
 622                 else
 623                         pn->left  = ln;
 624
 625                 if (addr_bit_set(&key->addr, plen))
 626                         ln->right = fn;
 627                 else
 628                         ln->left  = fn;
 629
 630                 fn->parent = ln;
 631         }
 632         return ln;
 633 }
 634
 635 static inline bool rt6_qualify_for_ecmp(struct rt6_info *rt)
 636 {
 637         return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
 638                RTF_GATEWAY;
 639 }
 640
 641 /*
 642  *      Insert routing information in a node.
 643  */
 644
 645 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 646                             struct nl_info *info)
 647 {
 648         struct rt6_info *iter = NULL;
 649         struct rt6_info **ins;
 650         int replace = (info->nlh &&
 651                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 652         int add = (!info->nlh ||
 653                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
 654         int found = 0;
 655         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
 656
 657         ins = &fn->leaf;
 658
 659         for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
 660                 /*
 661                  *      Search for duplicates
 662                  */
 663
 664                 if (iter->rt6i_metric == rt->rt6i_metric) {
 665                         /*
 666                          *      Same priority level
 667                          */
 668                         if (info->nlh &&
 669                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
 670                                 return -EEXIST;
 671                         if (replace) {
 672                                 found++;
 673                                 break;
 674                         }
 675
 676                         if (iter->dst.dev == rt->dst.dev &&
 677                             iter->rt6i_idev == rt->rt6i_idev &&
 678                             ipv6_addr_equal(&iter->rt6i_gateway,
 679                                             &rt->rt6i_gateway)) {
 680                                 if (rt->rt6i_nsiblings)
 681                                         rt->rt6i_nsiblings = 0;
 682                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
 683                                         return -EEXIST;
 684                                 if (!(rt->rt6i_flags & RTF_EXPIRES))
 685                                         rt6_clean_expires(iter);
 686                                 else
 687                                         rt6_set_expires(iter, rt->dst.expires);
 688                                 return -EEXIST;
 689                         }
 690                         /* If we have the same destination and the same metric,
 691                          * but not the same gateway, then the route we try to
 692                          * add is sibling to this route, increment our counter
 693                          * of siblings, and later we will add our route to the
 694                          * list.
 695                          * Only static routes (which don't have flag
 696                          * RTF_EXPIRES) are used for ECMPv6.
 697                          *
 698                          * To avoid long list, we only had siblings if the
 699                          * route have a gateway.
 700                          */
 701                         if (rt_can_ecmp &&
 702                             rt6_qualify_for_ecmp(iter))
 703                                 rt->rt6i_nsiblings++;
 704                 }
 705
 706                 if (iter->rt6i_metric > rt->rt6i_metric)
 707                         break;
 708
 709                 ins = &iter->dst.rt6_next;
 710         }
 711
 712         /* Reset round-robin state, if necessary */
 713         if (ins == &fn->leaf)
 714                 fn->rr_ptr = NULL;
 715
 716         /* Link this route to others same route. */
 717         if (rt->rt6i_nsiblings) {
 718                 unsigned int rt6i_nsiblings;
 719                 struct rt6_info *sibling, *temp_sibling;
 720
 721                 /* Find the first route that have the same metric */
 722                 sibling = fn->leaf;
 723                 while (sibling) {
 724                         if (sibling->rt6i_metric == rt->rt6i_metric &&
 725                             rt6_qualify_for_ecmp(sibling)) {
 726                                 list_add_tail(&rt->rt6i_siblings,
 727                                               &sibling->rt6i_siblings);
 728                                 break;
 729                         }
 730                         sibling = sibling->dst.rt6_next;
 731                 }
 732                 /* For each sibling in the list, increment the counter of
 733                  * siblings. BUG() if counters does not match, list of siblings
 734                  * is broken!
 735                  */
 736                 rt6i_nsiblings = 0;
 737                 list_for_each_entry_safe(sibling, temp_sibling,
 738                                          &rt->rt6i_siblings, rt6i_siblings) {
 739                         sibling->rt6i_nsiblings++;
 740                         BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
 741                         rt6i_nsiblings++;
 742                 }
 743                 BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
 744         }
 745
 746         /*
 747          *      insert node
 748          */
 749         if (!replace) {
 750                 if (!add)
 751                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
 752
 753 add:
 754                 rt->dst.rt6_next = iter;
 755                 *ins = rt;
 756                 rt->rt6i_node = fn;
 757                 atomic_inc(&rt->rt6i_ref);
 758                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 759                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 760
 761                 if (!(fn->fn_flags & RTN_RTINFO)) {
 762                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 763                         fn->fn_flags |= RTN_RTINFO;
 764                 }
 765
 766         } else {
 767                 if (!found) {
 768                         if (add)
 769                                 goto add;
 770                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
 771                         return -ENOENT;
 772                 }
 773                 *ins = rt;
 774                 rt->rt6i_node = fn;
 775                 rt->dst.rt6_next = iter->dst.rt6_next;
 776                 atomic_inc(&rt->rt6i_ref);
 777                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 778                 rt6_release(iter);
 779                 if (!(fn->fn_flags & RTN_RTINFO)) {
 780                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 781                         fn->fn_flags |= RTN_RTINFO;
 782                 }
 783         }
 784
 785         return 0;
 786 }
 787
 788 static __inline__ void fib6_start_gc(struct net *net, struct rt6_info *rt)
 789 {
 790         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 791             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 792                 mod_timer(&net->ipv6.ip6_fib_timer,
 793                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 794 }
 795
 796 void fib6_force_start_gc(struct net *net)
 797 {
 798         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 799                 mod_timer(&net->ipv6.ip6_fib_timer,
 800                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 801 }
 802
 803 /*
 804  *      Add routing information to the routing tree.
 805  *      <destination addr>/<source addr>
 806  *      with source addr info in sub-trees
 807  */
 808
 809 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
 810 {
 811         struct fib6_node *fn, *pn = NULL;
 812         int err = -ENOMEM;
 813         int allow_create = 1;
 814         int replace_required = 0;
 815
 816         if (info->nlh) {
 817                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 818                         allow_create = 0;
 819                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 820                         replace_required = 1;
 821         }
 822         if (!allow_create && !replace_required)
 823                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 824
 825         fn = fib6_add_1(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
 826                         offsetof(struct rt6_info, rt6i_dst), allow_create,
 827                         replace_required);
 828         if (IS_ERR(fn)) {
 829                 err = PTR_ERR(fn);
 830                 fn = NULL;
 831                 goto out;
 832         }
 833
 834         pn = fn;
 835
 836 #ifdef CONFIG_IPV6_SUBTREES
 837         if (rt->rt6i_src.plen) {
 838                 struct fib6_node *sn;
 839
 840                 if (!fn->subtree) {
 841                         struct fib6_node *sfn;
 842
 843                         /*
 844                          * Create subtree.
 845                          *
 846                          *              fn[main tree]
 847                          *              |
 848                          *              sfn[subtree root]
 849                          *                 \
 850                          *                  sn[new leaf node]
 851                          */
 852
 853                         /* Create subtree root node */
 854                         sfn = node_alloc();
 855                         if (!sfn)
 856                                 goto st_failure;
 857
 858                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 859                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 860                         sfn->fn_flags = RTN_ROOT;
 861                         sfn->fn_sernum = fib6_new_sernum();
 862
 863                         /* Now add the first leaf node to new subtree */
 864
 865                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 866                                         rt->rt6i_src.plen,
 867                                         offsetof(struct rt6_info, rt6i_src),
 868                                         allow_create, replace_required);
 869
 870                         if (IS_ERR(sn)) {
 871                                 /* If it is failed, discard just allocated
 872                                    root, and then (in st_failure) stale node
 873                                    in main tree.
 874                                  */
 875                                 node_free(sfn);
 876                                 err = PTR_ERR(sn);
 877                                 goto st_failure;
 878                         }
 879
 880                         /* Now link new subtree to main tree */
 881                         sfn->parent = fn;
 882                         fn->subtree = sfn;
 883                 } else {
 884                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 885                                         rt->rt6i_src.plen,
 886                                         offsetof(struct rt6_info, rt6i_src),
 887                                         allow_create, replace_required);
 888
 889                         if (IS_ERR(sn)) {
 890                                 err = PTR_ERR(sn);
 891                                 goto st_failure;
 892                         }
 893                 }
 894
 895                 if (!fn->leaf) {
 896                         fn->leaf = rt;
 897                         atomic_inc(&rt->rt6i_ref);
 898                 }
 899                 fn = sn;
 900         }
 901 #endif
 902
 903         err = fib6_add_rt2node(fn, rt, info);
 904         if (!err) {
 905                 fib6_start_gc(info->nl_net, rt);
 906                 if (!(rt->rt6i_flags & RTF_CACHE))
 907                         fib6_prune_clones(info->nl_net, pn, rt);
 908         }
 909
 910 out:
 911         if (err) {
 912 #ifdef CONFIG_IPV6_SUBTREES
 913                 /*
 914                  * If fib6_add_1 has cleared the old leaf pointer in the
 915                  * super-tree leaf node we have to find a new one for it.
 916                  */
 917                 if (pn != fn && pn->leaf == rt) {
 918                         pn->leaf = NULL;
 919                         atomic_dec(&rt->rt6i_ref);
 920                 }
 921                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 922                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
 923 #if RT6_DEBUG >= 2
 924                         if (!pn->leaf) {
 925                                 WARN_ON(pn->leaf == NULL);
 926                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 927                         }
 928 #endif
 929                         atomic_inc(&pn->leaf->rt6i_ref);
 930                 }
 931 #endif
 932                 dst_free(&rt->dst);
 933         }
 934         return err;
 935
 936 #ifdef CONFIG_IPV6_SUBTREES
 937         /* Subtree creation failed, probably main tree node
 938            is orphan. If it is, shoot it.
 939          */
 940 st_failure:
 941         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 942                 fib6_repair_tree(info->nl_net, fn);
 943         dst_free(&rt->dst);
 944         return err;
 945 #endif
 946 }
 947
 948 /*
 949  *      Routing tree lookup
 950  *
 951  */
 952
 953 struct lookup_args {
 954         int                     offset;         /* key offset on rt6_info       */
 955         const struct in6_addr   *addr;          /* search key                   */
 956 };
 957
 958 static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 959                                         struct lookup_args *args)
 960 {
 961         struct fib6_node *fn;
 962         __be32 dir;
 963
 964         if (unlikely(args->offset == 0))
 965                 return NULL;
 966
 967         /*
 968          *      Descend on a tree
 969          */
 970
 971         fn = root;
 972
 973         for (;;) {
 974                 struct fib6_node *next;
 975
 976                 dir = addr_bit_set(args->addr, fn->fn_bit);
 977
 978                 next = dir ? fn->right : fn->left;
 979
 980                 if (next) {
 981                         fn = next;
 982                         continue;
 983                 }
 984                 break;
 985         }
 986
 987         while (fn) {
 988                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
 989                         struct rt6key *key;
 990
 991                         key = (struct rt6key *) ((u8 *) fn->leaf +
 992                                                  args->offset);
 993
 994                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 995 #ifdef CONFIG_IPV6_SUBTREES
 996                                 if (fn->subtree) {
 997                                         struct fib6_node *sfn;
 998                                         sfn = fib6_lookup_1(fn->subtree,
 999                                                             args + 1);
1000                                         if (!sfn)
1001                                                 goto backtrack;
1002                                         fn = sfn;
1003                                 }
1004 #endif
1005                                 if (fn->fn_flags & RTN_RTINFO)
1006                                         return fn;
1007                         }
1008                 }
1009 #ifdef CONFIG_IPV6_SUBTREES
1010 backtrack:
1011 #endif
1012                 if (fn->fn_flags & RTN_ROOT)
1013                         break;
1014
1015                 fn = fn->parent;
1016         }
1017
1018         return NULL;
1019 }
1020
1021 struct fib6_node * fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
1022                                const struct in6_addr *saddr)
1023 {
1024         struct fib6_node *fn;
1025         struct lookup_args args[] = {
1026                 {
1027                         .offset = offsetof(struct rt6_info, rt6i_dst),
1028                         .addr = daddr,
1029                 },
1030 #ifdef CONFIG_IPV6_SUBTREES
1031                 {
1032                         .offset = offsetof(struct rt6_info, rt6i_src),
1033                         .addr = saddr,
1034                 },
1035 #endif
1036                 {
1037                         .offset = 0,    /* sentinel */
1038                 }
1039         };
1040
1041         fn = fib6_lookup_1(root, daddr ? args : args + 1);
1042         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1043                 fn = root;
1044
1045         return fn;
1046 }
1047
1048 /*
1049  *      Get node with specified destination prefix (and source prefix,
1050  *      if subtrees are used)
1051  */
1052
1053
1054 static struct fib6_node * fib6_locate_1(struct fib6_node *root,
1055                                         const struct in6_addr *addr,
1056                                         int plen, int offset)
1057 {
1058         struct fib6_node *fn;
1059
1060         for (fn = root; fn ; ) {
1061                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1062
1063                 /*
1064                  *      Prefix match
1065                  */
1066                 if (plen < fn->fn_bit ||
1067                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1068                         return NULL;
1069
1070                 if (plen == fn->fn_bit)
1071                         return fn;
1072
1073                 /*
1074                  *      We have more bits to go
1075                  */
1076                 if (addr_bit_set(addr, fn->fn_bit))
1077                         fn = fn->right;
1078                 else
1079                         fn = fn->left;
1080         }
1081         return NULL;
1082 }
1083
1084 struct fib6_node * fib6_locate(struct fib6_node *root,
1085                                const struct in6_addr *daddr, int dst_len,
1086                                const struct in6_addr *saddr, int src_len)
1087 {
1088         struct fib6_node *fn;
1089
1090         fn = fib6_locate_1(root, daddr, dst_len,
1091                            offsetof(struct rt6_info, rt6i_dst));
1092
1093 #ifdef CONFIG_IPV6_SUBTREES
1094         if (src_len) {
1095                 WARN_ON(saddr == NULL);
1096                 if (fn && fn->subtree)
1097                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
1098                                            offsetof(struct rt6_info, rt6i_src));
1099         }
1100 #endif
1101
1102         if (fn && fn->fn_flags & RTN_RTINFO)
1103                 return fn;
1104
1105         return NULL;
1106 }
1107
1108
1109 /*
1110  *      Deletion
1111  *
1112  */
1113
1114 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1115 {
1116         if (fn->fn_flags & RTN_ROOT)
1117                 return net->ipv6.ip6_null_entry;
1118
1119         while (fn) {
1120                 if (fn->left)
1121                         return fn->left->leaf;
1122                 if (fn->right)
1123                         return fn->right->leaf;
1124
1125                 fn = FIB6_SUBTREE(fn);
1126         }
1127         return NULL;
1128 }
1129
1130 /*
1131  *      Called to trim the tree of intermediate nodes when possible. "fn"
1132  *      is the node we want to try and remove.
1133  */
1134
1135 static struct fib6_node *fib6_repair_tree(struct net *net,
1136                                            struct fib6_node *fn)
1137 {
1138         int children;
1139         int nstate;
1140         struct fib6_node *child, *pn;
1141         struct fib6_walker_t *w;
1142         int iter = 0;
1143
1144         for (;;) {
1145                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1146                 iter++;
1147
1148                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1149                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1150                 WARN_ON(fn->leaf != NULL);
1151
1152                 children = 0;
1153                 child = NULL;
1154                 if (fn->right) child = fn->right, children |= 1;
1155                 if (fn->left) child = fn->left, children |= 2;
1156
1157                 if (children == 3 || FIB6_SUBTREE(fn)
1158 #ifdef CONFIG_IPV6_SUBTREES
1159                     /* Subtree root (i.e. fn) may have one child */
1160                     || (children && fn->fn_flags & RTN_ROOT)
1161 #endif
1162                     ) {
1163                         fn->leaf = fib6_find_prefix(net, fn);
1164 #if RT6_DEBUG >= 2
1165                         if (!fn->leaf) {
1166                                 WARN_ON(!fn->leaf);
1167                                 fn->leaf = net->ipv6.ip6_null_entry;
1168                         }
1169 #endif
1170                         atomic_inc(&fn->leaf->rt6i_ref);
1171                         return fn->parent;
1172                 }
1173
1174                 pn = fn->parent;
1175 #ifdef CONFIG_IPV6_SUBTREES
1176                 if (FIB6_SUBTREE(pn) == fn) {
1177                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1178                         FIB6_SUBTREE(pn) = NULL;
1179                         nstate = FWS_L;
1180                 } else {
1181                         WARN_ON(fn->fn_flags & RTN_ROOT);
1182 #endif
1183                         if (pn->right == fn) pn->right = child;
1184                         else if (pn->left == fn) pn->left = child;
1185 #if RT6_DEBUG >= 2
1186                         else
1187                                 WARN_ON(1);
1188 #endif
1189                         if (child)
1190                                 child->parent = pn;
1191                         nstate = FWS_R;
1192 #ifdef CONFIG_IPV6_SUBTREES
1193                 }
1194 #endif
1195
1196                 read_lock(&fib6_walker_lock);
1197                 FOR_WALKERS(w) {
1198                         if (!child) {
1199                                 if (w->root == fn) {
1200                                         w->root = w->node = NULL;
1201                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1202                                 } else if (w->node == fn) {
1203                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1204                                         w->node = pn;
1205                                         w->state = nstate;
1206                                 }
1207                         } else {
1208                                 if (w->root == fn) {
1209                                         w->root = child;
1210                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1211                                 }
1212                                 if (w->node == fn) {
1213                                         w->node = child;
1214                                         if (children&2) {
1215                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1216                                                 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1217                                         } else {
1218                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1219                                                 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1220                                         }
1221                                 }
1222                         }
1223                 }
1224                 read_unlock(&fib6_walker_lock);
1225
1226                 node_free(fn);
1227                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1228                         return pn;
1229
1230                 rt6_release(pn->leaf);
1231                 pn->leaf = NULL;
1232                 fn = pn;
1233         }
1234 }
1235
1236 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1237                            struct nl_info *info)
1238 {
1239         struct fib6_walker_t *w;
1240         struct rt6_info *rt = *rtp;
1241         struct net *net = info->nl_net;
1242
1243         RT6_TRACE("fib6_del_route\n");
1244
1245         /* Unlink it */
1246         *rtp = rt->dst.rt6_next;
1247         rt->rt6i_node = NULL;
1248         net->ipv6.rt6_stats->fib_rt_entries--;
1249         net->ipv6.rt6_stats->fib_discarded_routes++;
1250
1251         /* Reset round-robin state, if necessary */
1252         if (fn->rr_ptr == rt)
1253                 fn->rr_ptr = NULL;
1254
1255         /* Remove this entry from other siblings */
1256         if (rt->rt6i_nsiblings) {
1257                 struct rt6_info *sibling, *next_sibling;
1258
1259                 list_for_each_entry_safe(sibling, next_sibling,
1260                                          &rt->rt6i_siblings, rt6i_siblings)
1261                         sibling->rt6i_nsiblings--;
1262                 rt->rt6i_nsiblings = 0;
1263                 list_del_init(&rt->rt6i_siblings);
1264         }
1265
1266         /* Adjust walkers */
1267         read_lock(&fib6_walker_lock);
1268         FOR_WALKERS(w) {
1269                 if (w->state == FWS_C && w->leaf == rt) {
1270                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1271                         w->leaf = rt->dst.rt6_next;
1272                         if (!w->leaf)
1273                                 w->state = FWS_U;
1274                 }
1275         }
1276         read_unlock(&fib6_walker_lock);
1277
1278         rt->dst.rt6_next = NULL;
1279
1280         /* If it was last route, expunge its radix tree node */
1281         if (!fn->leaf) {
1282                 fn->fn_flags &= ~RTN_RTINFO;
1283                 net->ipv6.rt6_stats->fib_route_nodes--;
1284                 fn = fib6_repair_tree(net, fn);
1285         }
1286
1287         if (atomic_read(&rt->rt6i_ref) != 1) {
1288                 /* This route is used as dummy address holder in some split
1289                  * nodes. It is not leaked, but it still holds other resources,
1290                  * which must be released in time. So, scan ascendant nodes
1291                  * and replace dummy references to this route with references
1292                  * to still alive ones.
1293                  */
1294                 while (fn) {
1295                         if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
1296                                 fn->leaf = fib6_find_prefix(net, fn);
1297                                 atomic_inc(&fn->leaf->rt6i_ref);
1298                                 rt6_release(rt);
1299                         }
1300                         fn = fn->parent;
1301                 }
1302                 /* No more references are possible at this point. */
1303                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1304         }
1305
1306         inet6_rt_notify(RTM_DELROUTE, rt, info);
1307         rt6_release(rt);
1308 }
1309
1310 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1311 {
1312         struct net *net = info->nl_net;
1313         struct fib6_node *fn = rt->rt6i_node;
1314         struct rt6_info **rtp;
1315
1316 #if RT6_DEBUG >= 2
1317         if (rt->dst.obsolete>0) {
1318                 WARN_ON(fn != NULL);
1319                 return -ENOENT;
1320         }
1321 #endif
1322         if (!fn || rt == net->ipv6.ip6_null_entry)
1323                 return -ENOENT;
1324
1325         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1326
1327         if (!(rt->rt6i_flags & RTF_CACHE)) {
1328                 struct fib6_node *pn = fn;
1329 #ifdef CONFIG_IPV6_SUBTREES
1330                 /* clones of this route might be in another subtree */
1331                 if (rt->rt6i_src.plen) {
1332                         while (!(pn->fn_flags & RTN_ROOT))
1333                                 pn = pn->parent;
1334                         pn = pn->parent;
1335                 }
1336 #endif
1337                 fib6_prune_clones(info->nl_net, pn, rt);
1338         }
1339
1340         /*
1341          *      Walk the leaf entries looking for ourself
1342          */
1343
1344         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1345                 if (*rtp == rt) {
1346                         fib6_del_route(fn, rtp, info);
1347                         return 0;
1348                 }
1349         }
1350         return -ENOENT;
1351 }
1352
1353 /*
1354  *      Tree traversal function.
1355  *
1356  *      Certainly, it is not interrupt safe.
1357  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1358  *      It means, that we can modify tree during walking
1359  *      and use this function for garbage collection, clone pruning,
1360  *      cleaning tree when a device goes down etc. etc.
1361  *
1362  *      It guarantees that every node will be traversed,
1363  *      and that it will be traversed only once.
1364  *
1365  *      Callback function w->func may return:
1366  *      0 -> continue walking.
1367  *      positive value -> walking is suspended (used by tree dumps,
1368  *      and probably by gc, if it will be split to several slices)
1369  *      negative value -> terminate walking.
1370  *
1371  *      The function itself returns:
1372  *      0   -> walk is complete.
1373  *      >0  -> walk is incomplete (i.e. suspended)
1374  *      <0  -> walk is terminated by an error.
1375  */
1376
1377 static int fib6_walk_continue(struct fib6_walker_t *w)
1378 {
1379         struct fib6_node *fn, *pn;
1380
1381         for (;;) {
1382                 fn = w->node;
1383                 if (!fn)
1384                         return 0;
1385
1386                 if (w->prune && fn != w->root &&
1387                     fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1388                         w->state = FWS_C;
1389                         w->leaf = fn->leaf;
1390                 }
1391                 switch (w->state) {
1392 #ifdef CONFIG_IPV6_SUBTREES
1393                 case FWS_S:
1394                         if (FIB6_SUBTREE(fn)) {
1395                                 w->node = FIB6_SUBTREE(fn);
1396                                 continue;
1397                         }
1398                         w->state = FWS_L;
1399 #endif
1400                 case FWS_L:
1401                         if (fn->left) {
1402                                 w->node = fn->left;
1403                                 w->state = FWS_INIT;
1404                                 continue;
1405                         }
1406                         w->state = FWS_R;
1407                 case FWS_R:
1408                         if (fn->right) {
1409                                 w->node = fn->right;
1410                                 w->state = FWS_INIT;
1411                                 continue;
1412                         }
1413                         w->state = FWS_C;
1414                         w->leaf = fn->leaf;
1415                 case FWS_C:
1416                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1417                                 int err;
1418
1419                                 if (w->skip) {
1420                                         w->skip--;
1421                                         continue;
1422                                 }
1423
1424                                 err = w->func(w);
1425                                 if (err)
1426                                         return err;
1427
1428                                 w->count++;
1429                                 continue;
1430                         }
1431                         w->state = FWS_U;
1432                 case FWS_U:
1433                         if (fn == w->root)
1434                                 return 0;
1435                         pn = fn->parent;
1436                         w->node = pn;
1437 #ifdef CONFIG_IPV6_SUBTREES
1438                         if (FIB6_SUBTREE(pn) == fn) {
1439                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1440                                 w->state = FWS_L;
1441                                 continue;
1442                         }
1443 #endif
1444                         if (pn->left == fn) {
1445                                 w->state = FWS_R;
1446                                 continue;
1447                         }
1448                         if (pn->right == fn) {
1449                                 w->state = FWS_C;
1450                                 w->leaf = w->node->leaf;
1451                                 continue;
1452                         }
1453 #if RT6_DEBUG >= 2
1454                         WARN_ON(1);
1455 #endif
1456                 }
1457         }
1458 }
1459
1460 static int fib6_walk(struct fib6_walker_t *w)
1461 {
1462         int res;
1463
1464         w->state = FWS_INIT;
1465         w->node = w->root;
1466
1467         fib6_walker_link(w);
1468         res = fib6_walk_continue(w);
1469         if (res <= 0)
1470                 fib6_walker_unlink(w);
1471         return res;
1472 }
1473
1474 static int fib6_clean_node(struct fib6_walker_t *w)
1475 {
1476         int res;
1477         struct rt6_info *rt;
1478         struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1479         struct nl_info info = {
1480                 .nl_net = c->net,
1481         };
1482
1483         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1484                 res = c->func(rt, c->arg);
1485                 if (res < 0) {
1486                         w->leaf = rt;
1487                         res = fib6_del(rt, &info);
1488                         if (res) {
1489 #if RT6_DEBUG >= 2
1490                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1491                                          __func__, rt, rt->rt6i_node, res);
1492 #endif
1493                                 continue;
1494                         }
1495                         return 0;
1496                 }
1497                 WARN_ON(res != 0);
1498         }
1499         w->leaf = rt;
1500         return 0;
1501 }
1502
1503 /*
1504  *      Convenient frontend to tree walker.
1505  *
1506  *      func is called on each route.
1507  *              It may return -1 -> delete this route.
1508  *                            0  -> continue walking
1509  *
1510  *      prune==1 -> only immediate children of node (certainly,
1511  *      ignoring pure split nodes) will be scanned.
1512  */
1513
1514 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1515                             int (*func)(struct rt6_info *, void *arg),
1516                             int prune, void *arg)
1517 {
1518         struct fib6_cleaner_t c;
1519
1520         c.w.root = root;
1521         c.w.func = fib6_clean_node;
1522         c.w.prune = prune;
1523         c.w.count = 0;
1524         c.w.skip = 0;
1525         c.func = func;
1526         c.arg = arg;
1527         c.net = net;
1528
1529         fib6_walk(&c.w);
1530 }
1531
1532 void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg),
1533                     int prune, void *arg)
1534 {
1535         struct fib6_table *table;
1536         struct hlist_head *head;
1537         unsigned int h;
1538
1539         rcu_read_lock();
1540         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1541                 head = &net->ipv6.fib_table_hash[h];
1542                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1543                         read_lock_bh(&table->tb6_lock);
1544                         fib6_clean_tree(net, &table->tb6_root,
1545                                         func, prune, arg);
1546                         read_unlock_bh(&table->tb6_lock);
1547                 }
1548         }
1549         rcu_read_unlock();
1550 }
1551 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
1552                     int prune, void *arg)
1553 {
1554         struct fib6_table *table;
1555         struct hlist_head *head;
1556         unsigned int h;
1557
1558         rcu_read_lock();
1559         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1560                 head = &net->ipv6.fib_table_hash[h];
1561                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1562                         write_lock_bh(&table->tb6_lock);
1563                         fib6_clean_tree(net, &table->tb6_root,
1564                                         func, prune, arg);
1565                         write_unlock_bh(&table->tb6_lock);
1566                 }
1567         }
1568         rcu_read_unlock();
1569 }
1570
1571 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1572 {
1573         if (rt->rt6i_flags & RTF_CACHE) {
1574                 RT6_TRACE("pruning clone %p\n", rt);
1575                 return -1;
1576         }
1577
1578         return 0;
1579 }
1580
1581 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
1582                               struct rt6_info *rt)
1583 {
1584         fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
1585 }
1586
1587 /*
1588  *      Garbage collection
1589  */
1590
1591 static struct fib6_gc_args
1592 {
1593         int                     timeout;
1594         int                     more;
1595 } gc_args;
1596
1597 static int fib6_age(struct rt6_info *rt, void *arg)
1598 {
1599         unsigned long now = jiffies;
1600
1601         /*
1602          *      check addrconf expiration here.
1603          *      Routes are expired even if they are in use.
1604          *
1605          *      Also age clones. Note, that clones are aged out
1606          *      only if they are not in use now.
1607          */
1608
1609         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1610                 if (time_after(now, rt->dst.expires)) {
1611                         RT6_TRACE("expiring %p\n", rt);
1612                         return -1;
1613                 }
1614                 gc_args.more++;
1615         } else if (rt->rt6i_flags & RTF_CACHE) {
1616                 if (atomic_read(&rt->dst.__refcnt) == 0 &&
1617                     time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1618                         RT6_TRACE("aging clone %p\n", rt);
1619                         return -1;
1620                 } else if (rt->rt6i_flags & RTF_GATEWAY) {
1621                         struct neighbour *neigh;
1622                         __u8 neigh_flags = 0;
1623
1624                         neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1625                         if (neigh) {
1626                                 neigh_flags = neigh->flags;
1627                                 neigh_release(neigh);
1628                         }
1629                         if (!(neigh_flags & NTF_ROUTER)) {
1630                                 RT6_TRACE("purging route %p via non-router but gateway\n",
1631                                           rt);
1632                                 return -1;
1633                         }
1634                 }
1635                 gc_args.more++;
1636         }
1637
1638         return 0;
1639 }
1640
1641 static DEFINE_SPINLOCK(fib6_gc_lock);
1642
1643 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
1644 {
1645         unsigned long now;
1646
1647         if (force) {
1648                 spin_lock_bh(&fib6_gc_lock);
1649         } else if (!spin_trylock_bh(&fib6_gc_lock)) {
1650                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1651                 return;
1652         }
1653         gc_args.timeout = expires ? (int)expires :
1654                           net->ipv6.sysctl.ip6_rt_gc_interval;
1655
1656         gc_args.more = icmp6_dst_gc();
1657
1658         fib6_clean_all(net, fib6_age, 0, NULL);
1659         now = jiffies;
1660         net->ipv6.ip6_rt_last_gc = now;
1661
1662         if (gc_args.more)
1663                 mod_timer(&net->ipv6.ip6_fib_timer,
1664                           round_jiffies(now
1665                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1666         else
1667                 del_timer(&net->ipv6.ip6_fib_timer);
1668         spin_unlock_bh(&fib6_gc_lock);
1669 }
1670
1671 static void fib6_gc_timer_cb(unsigned long arg)
1672 {
1673         fib6_run_gc(0, (struct net *)arg, true);
1674 }
1675
1676 static int __net_init fib6_net_init(struct net *net)
1677 {
1678         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1679
1680         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1681
1682         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1683         if (!net->ipv6.rt6_stats)
1684                 goto out_timer;
1685
1686         /* Avoid false sharing : Use at least a full cache line */
1687         size = max_t(size_t, size, L1_CACHE_BYTES);
1688
1689         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1690         if (!net->ipv6.fib_table_hash)
1691                 goto out_rt6_stats;
1692
1693         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1694                                           GFP_KERNEL);
1695         if (!net->ipv6.fib6_main_tbl)
1696                 goto out_fib_table_hash;
1697
1698         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1699         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1700         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1701                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1702         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1703
1704 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1705         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1706                                            GFP_KERNEL);
1707         if (!net->ipv6.fib6_local_tbl)
1708                 goto out_fib6_main_tbl;
1709         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1710         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1711         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1712                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1713         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1714 #endif
1715         fib6_tables_init(net);
1716
1717         return 0;
1718
1719 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1720 out_fib6_main_tbl:
1721         kfree(net->ipv6.fib6_main_tbl);
1722 #endif
1723 out_fib_table_hash:
1724         kfree(net->ipv6.fib_table_hash);
1725 out_rt6_stats:
1726         kfree(net->ipv6.rt6_stats);
1727 out_timer:
1728         return -ENOMEM;
1729  }
1730
1731 static void fib6_net_exit(struct net *net)
1732 {
1733         rt6_ifdown(net, NULL);
1734         del_timer_sync(&net->ipv6.ip6_fib_timer);
1735
1736 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1737         inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1738         kfree(net->ipv6.fib6_local_tbl);
1739 #endif
1740         inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1741         kfree(net->ipv6.fib6_main_tbl);
1742         kfree(net->ipv6.fib_table_hash);
1743         kfree(net->ipv6.rt6_stats);
1744 }
1745
1746 static struct pernet_operations fib6_net_ops = {
1747         .init = fib6_net_init,
1748         .exit = fib6_net_exit,
1749 };
1750
1751 int __init fib6_init(void)
1752 {
1753         int ret = -ENOMEM;
1754
1755         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1756                                            sizeof(struct fib6_node),
1757                                            0, SLAB_HWCACHE_ALIGN,
1758                                            NULL);
1759         if (!fib6_node_kmem)
1760                 goto out;
1761
1762         ret = register_pernet_subsys(&fib6_net_ops);
1763         if (ret)
1764                 goto out_kmem_cache_create;
1765
1766         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1767                               NULL);
1768         if (ret)
1769                 goto out_unregister_subsys;
1770 out:
1771         return ret;
1772
1773 out_unregister_subsys:
1774         unregister_pernet_subsys(&fib6_net_ops);
1775 out_kmem_cache_create:
1776         kmem_cache_destroy(fib6_node_kmem);
1777         goto out;
1778 }
1779
1780 void fib6_gc_cleanup(void)
1781 {
1782         unregister_pernet_subsys(&fib6_net_ops);
1783         kmem_cache_destroy(fib6_node_kmem);
1784 }