Pileus Git - ~andy/linux/blob - net/ipv6/ip6_fib.c

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