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         }
 201
 202         return table;
 203 }
 204
 205 struct fib6_table *fib6_new_table(struct net *net, u32 id)
 206 {
 207         struct fib6_table *tb;
 208
 209         if (id == 0)
 210                 id = RT6_TABLE_MAIN;
 211         tb = fib6_get_table(net, id);
 212         if (tb)
 213                 return tb;
 214
 215         tb = fib6_alloc_table(net, id);
 216         if (tb)
 217                 fib6_link_table(net, tb);
 218
 219         return tb;
 220 }
 221
 222 struct fib6_table *fib6_get_table(struct net *net, u32 id)
 223 {
 224         struct fib6_table *tb;
 225         struct hlist_head *head;
 226         struct hlist_node *node;
 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, node, 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_node *node;
 366         struct hlist_head *head;
 367         int res = 0;
 368
 369         s_h = cb->args[0];
 370         s_e = cb->args[1];
 371
 372         w = (void *)cb->args[2];
 373         if (!w) {
 374                 /* New dump:
 375                  *
 376                  * 1. hook callback destructor.
 377                  */
 378                 cb->args[3] = (long)cb->done;
 379                 cb->done = fib6_dump_done;
 380
 381                 /*
 382                  * 2. allocate and initialize walker.
 383                  */
 384                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
 385                 if (!w)
 386                         return -ENOMEM;
 387                 w->func = fib6_dump_node;
 388                 cb->args[2] = (long)w;
 389         }
 390
 391         arg.skb = skb;
 392         arg.cb = cb;
 393         arg.net = net;
 394         w->args = &arg;
 395
 396         rcu_read_lock();
 397         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 398                 e = 0;
 399                 head = &net->ipv6.fib_table_hash[h];
 400                 hlist_for_each_entry_rcu(tb, node, head, tb6_hlist) {
 401                         if (e < s_e)
 402                                 goto next;
 403                         res = fib6_dump_table(tb, skb, cb);
 404                         if (res != 0)
 405                                 goto out;
 406 next:
 407                         e++;
 408                 }
 409         }
 410 out:
 411         rcu_read_unlock();
 412         cb->args[1] = e;
 413         cb->args[0] = h;
 414
 415         res = res < 0 ? res : skb->len;
 416         if (res <= 0)
 417                 fib6_dump_end(cb);
 418         return res;
 419 }
 420
 421 /*
 422  *      Routing Table
 423  *
 424  *      return the appropriate node for a routing tree "add" operation
 425  *      by either creating and inserting or by returning an existing
 426  *      node.
 427  */
 428
 429 static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
 430                                      int addrlen, int plen,
 431                                      int offset, int allow_create,
 432                                      int replace_required)
 433 {
 434         struct fib6_node *fn, *in, *ln;
 435         struct fib6_node *pn = NULL;
 436         struct rt6key *key;
 437         int     bit;
 438         __be32  dir = 0;
 439         __u32   sernum = fib6_new_sernum();
 440
 441         RT6_TRACE("fib6_add_1\n");
 442
 443         /* insert node in tree */
 444
 445         fn = root;
 446
 447         do {
 448                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
 449
 450                 /*
 451                  *      Prefix match
 452                  */
 453                 if (plen < fn->fn_bit ||
 454                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 455                         if (!allow_create) {
 456                                 if (replace_required) {
 457                                         pr_warn("Can't replace route, no match found\n");
 458                                         return ERR_PTR(-ENOENT);
 459                                 }
 460                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 461                         }
 462                         goto insert_above;
 463                 }
 464
 465                 /*
 466                  *      Exact match ?
 467                  */
 468
 469                 if (plen == fn->fn_bit) {
 470                         /* clean up an intermediate node */
 471                         if (!(fn->fn_flags & RTN_RTINFO)) {
 472                                 rt6_release(fn->leaf);
 473                                 fn->leaf = NULL;
 474                         }
 475
 476                         fn->fn_sernum = sernum;
 477
 478                         return fn;
 479                 }
 480
 481                 /*
 482                  *      We have more bits to go
 483                  */
 484
 485                 /* Try to walk down on tree. */
 486                 fn->fn_sernum = sernum;
 487                 dir = addr_bit_set(addr, fn->fn_bit);
 488                 pn = fn;
 489                 fn = dir ? fn->right: fn->left;
 490         } while (fn);
 491
 492         if (!allow_create) {
 493                 /* We should not create new node because
 494                  * NLM_F_REPLACE was specified without NLM_F_CREATE
 495                  * I assume it is safe to require NLM_F_CREATE when
 496                  * REPLACE flag is used! Later we may want to remove the
 497                  * check for replace_required, because according
 498                  * to netlink specification, NLM_F_CREATE
 499                  * MUST be specified if new route is created.
 500                  * That would keep IPv6 consistent with IPv4
 501                  */
 502                 if (replace_required) {
 503                         pr_warn("Can't replace route, no match found\n");
 504                         return ERR_PTR(-ENOENT);
 505                 }
 506                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
 507         }
 508         /*
 509          *      We walked to the bottom of tree.
 510          *      Create new leaf node without children.
 511          */
 512
 513         ln = node_alloc();
 514
 515         if (!ln)
 516                 return NULL;
 517         ln->fn_bit = plen;
 518
 519         ln->parent = pn;
 520         ln->fn_sernum = sernum;
 521
 522         if (dir)
 523                 pn->right = ln;
 524         else
 525                 pn->left  = ln;
 526
 527         return ln;
 528
 529
 530 insert_above:
 531         /*
 532          * split since we don't have a common prefix anymore or
 533          * we have a less significant route.
 534          * we've to insert an intermediate node on the list
 535          * this new node will point to the one we need to create
 536          * and the current
 537          */
 538
 539         pn = fn->parent;
 540
 541         /* find 1st bit in difference between the 2 addrs.
 542
 543            See comment in __ipv6_addr_diff: bit may be an invalid value,
 544            but if it is >= plen, the value is ignored in any case.
 545          */
 546
 547         bit = __ipv6_addr_diff(addr, &key->addr, addrlen);
 548
 549         /*
 550          *              (intermediate)[in]
 551          *                /        \
 552          *      (new leaf node)[ln] (old node)[fn]
 553          */
 554         if (plen > bit) {
 555                 in = node_alloc();
 556                 ln = node_alloc();
 557
 558                 if (!in || !ln) {
 559                         if (in)
 560                                 node_free(in);
 561                         if (ln)
 562                                 node_free(ln);
 563                         return NULL;
 564                 }
 565
 566                 /*
 567                  * new intermediate node.
 568                  * RTN_RTINFO will
 569                  * be off since that an address that chooses one of
 570                  * the branches would not match less specific routes
 571                  * in the other branch
 572                  */
 573
 574                 in->fn_bit = bit;
 575
 576                 in->parent = pn;
 577                 in->leaf = fn->leaf;
 578                 atomic_inc(&in->leaf->rt6i_ref);
 579
 580                 in->fn_sernum = sernum;
 581
 582                 /* update parent pointer */
 583                 if (dir)
 584                         pn->right = in;
 585                 else
 586                         pn->left  = in;
 587
 588                 ln->fn_bit = plen;
 589
 590                 ln->parent = in;
 591                 fn->parent = in;
 592
 593                 ln->fn_sernum = sernum;
 594
 595                 if (addr_bit_set(addr, bit)) {
 596                         in->right = ln;
 597                         in->left  = fn;
 598                 } else {
 599                         in->left  = ln;
 600                         in->right = fn;
 601                 }
 602         } else { /* plen <= bit */
 603
 604                 /*
 605                  *              (new leaf node)[ln]
 606                  *                /        \
 607                  *           (old node)[fn] NULL
 608                  */
 609
 610                 ln = node_alloc();
 611
 612                 if (!ln)
 613                         return NULL;
 614
 615                 ln->fn_bit = plen;
 616
 617                 ln->parent = pn;
 618
 619                 ln->fn_sernum = sernum;
 620
 621                 if (dir)
 622                         pn->right = ln;
 623                 else
 624                         pn->left  = ln;
 625
 626                 if (addr_bit_set(&key->addr, plen))
 627                         ln->right = fn;
 628                 else
 629                         ln->left  = fn;
 630
 631                 fn->parent = ln;
 632         }
 633         return ln;
 634 }
 635
 636 /*
 637  *      Insert routing information in a node.
 638  */
 639
 640 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 641                             struct nl_info *info)
 642 {
 643         struct rt6_info *iter = NULL;
 644         struct rt6_info **ins;
 645         int replace = (info->nlh &&
 646                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 647         int add = (!info->nlh ||
 648                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
 649         int found = 0;
 650
 651         ins = &fn->leaf;
 652
 653         for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
 654                 /*
 655                  *      Search for duplicates
 656                  */
 657
 658                 if (iter->rt6i_metric == rt->rt6i_metric) {
 659                         /*
 660                          *      Same priority level
 661                          */
 662                         if (info->nlh &&
 663                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
 664                                 return -EEXIST;
 665                         if (replace) {
 666                                 found++;
 667                                 break;
 668                         }
 669
 670                         if (iter->dst.dev == rt->dst.dev &&
 671                             iter->rt6i_idev == rt->rt6i_idev &&
 672                             ipv6_addr_equal(&iter->rt6i_gateway,
 673                                             &rt->rt6i_gateway)) {
 674                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
 675                                         return -EEXIST;
 676                                 if (!(rt->rt6i_flags & RTF_EXPIRES))
 677                                         rt6_clean_expires(iter);
 678                                 else
 679                                         rt6_set_expires(iter, rt->dst.expires);
 680                                 return -EEXIST;
 681                         }
 682                 }
 683
 684                 if (iter->rt6i_metric > rt->rt6i_metric)
 685                         break;
 686
 687                 ins = &iter->dst.rt6_next;
 688         }
 689
 690         /* Reset round-robin state, if necessary */
 691         if (ins == &fn->leaf)
 692                 fn->rr_ptr = NULL;
 693
 694         /*
 695          *      insert node
 696          */
 697         if (!replace) {
 698                 if (!add)
 699                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
 700
 701 add:
 702                 rt->dst.rt6_next = iter;
 703                 *ins = rt;
 704                 rt->rt6i_node = fn;
 705                 atomic_inc(&rt->rt6i_ref);
 706                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 707                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 708
 709                 if (!(fn->fn_flags & RTN_RTINFO)) {
 710                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 711                         fn->fn_flags |= RTN_RTINFO;
 712                 }
 713
 714         } else {
 715                 if (!found) {
 716                         if (add)
 717                                 goto add;
 718                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
 719                         return -ENOENT;
 720                 }
 721                 *ins = rt;
 722                 rt->rt6i_node = fn;
 723                 rt->dst.rt6_next = iter->dst.rt6_next;
 724                 atomic_inc(&rt->rt6i_ref);
 725                 inet6_rt_notify(RTM_NEWROUTE, rt, info);
 726                 rt6_release(iter);
 727                 if (!(fn->fn_flags & RTN_RTINFO)) {
 728                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 729                         fn->fn_flags |= RTN_RTINFO;
 730                 }
 731         }
 732
 733         return 0;
 734 }
 735
 736 static __inline__ void fib6_start_gc(struct net *net, struct rt6_info *rt)
 737 {
 738         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 739             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 740                 mod_timer(&net->ipv6.ip6_fib_timer,
 741                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 742 }
 743
 744 void fib6_force_start_gc(struct net *net)
 745 {
 746         if (!timer_pending(&net->ipv6.ip6_fib_timer))
 747                 mod_timer(&net->ipv6.ip6_fib_timer,
 748                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 749 }
 750
 751 /*
 752  *      Add routing information to the routing tree.
 753  *      <destination addr>/<source addr>
 754  *      with source addr info in sub-trees
 755  */
 756
 757 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
 758 {
 759         struct fib6_node *fn, *pn = NULL;
 760         int err = -ENOMEM;
 761         int allow_create = 1;
 762         int replace_required = 0;
 763
 764         if (info->nlh) {
 765                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 766                         allow_create = 0;
 767                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 768                         replace_required = 1;
 769         }
 770         if (!allow_create && !replace_required)
 771                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 772
 773         fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
 774                         rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst),
 775                         allow_create, replace_required);
 776
 777         if (IS_ERR(fn)) {
 778                 err = PTR_ERR(fn);
 779                 fn = NULL;
 780         }
 781
 782         if (!fn)
 783                 goto out;
 784
 785         pn = fn;
 786
 787 #ifdef CONFIG_IPV6_SUBTREES
 788         if (rt->rt6i_src.plen) {
 789                 struct fib6_node *sn;
 790
 791                 if (!fn->subtree) {
 792                         struct fib6_node *sfn;
 793
 794                         /*
 795                          * Create subtree.
 796                          *
 797                          *              fn[main tree]
 798                          *              |
 799                          *              sfn[subtree root]
 800                          *                 \
 801                          *                  sn[new leaf node]
 802                          */
 803
 804                         /* Create subtree root node */
 805                         sfn = node_alloc();
 806                         if (!sfn)
 807                                 goto st_failure;
 808
 809                         sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 810                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 811                         sfn->fn_flags = RTN_ROOT;
 812                         sfn->fn_sernum = fib6_new_sernum();
 813
 814                         /* Now add the first leaf node to new subtree */
 815
 816                         sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 817                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 818                                         offsetof(struct rt6_info, rt6i_src),
 819                                         allow_create, replace_required);
 820
 821                         if (!sn) {
 822                                 /* If it is failed, discard just allocated
 823                                    root, and then (in st_failure) stale node
 824                                    in main tree.
 825                                  */
 826                                 node_free(sfn);
 827                                 goto st_failure;
 828                         }
 829
 830                         /* Now link new subtree to main tree */
 831                         sfn->parent = fn;
 832                         fn->subtree = sfn;
 833                 } else {
 834                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 835                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
 836                                         offsetof(struct rt6_info, rt6i_src),
 837                                         allow_create, replace_required);
 838
 839                         if (IS_ERR(sn)) {
 840                                 err = PTR_ERR(sn);
 841                                 sn = NULL;
 842                         }
 843                         if (!sn)
 844                                 goto st_failure;
 845                 }
 846
 847                 if (!fn->leaf) {
 848                         fn->leaf = rt;
 849                         atomic_inc(&rt->rt6i_ref);
 850                 }
 851                 fn = sn;
 852         }
 853 #endif
 854
 855         err = fib6_add_rt2node(fn, rt, info);
 856         if (!err) {
 857                 fib6_start_gc(info->nl_net, rt);
 858                 if (!(rt->rt6i_flags & RTF_CACHE))
 859                         fib6_prune_clones(info->nl_net, pn, rt);
 860         }
 861
 862 out:
 863         if (err) {
 864 #ifdef CONFIG_IPV6_SUBTREES
 865                 /*
 866                  * If fib6_add_1 has cleared the old leaf pointer in the
 867                  * super-tree leaf node we have to find a new one for it.
 868                  */
 869                 if (pn != fn && pn->leaf == rt) {
 870                         pn->leaf = NULL;
 871                         atomic_dec(&rt->rt6i_ref);
 872                 }
 873                 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 874                         pn->leaf = fib6_find_prefix(info->nl_net, pn);
 875 #if RT6_DEBUG >= 2
 876                         if (!pn->leaf) {
 877                                 WARN_ON(pn->leaf == NULL);
 878                                 pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 879                         }
 880 #endif
 881                         atomic_inc(&pn->leaf->rt6i_ref);
 882                 }
 883 #endif
 884                 dst_free(&rt->dst);
 885         }
 886         return err;
 887
 888 #ifdef CONFIG_IPV6_SUBTREES
 889         /* Subtree creation failed, probably main tree node
 890            is orphan. If it is, shoot it.
 891          */
 892 st_failure:
 893         if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 894                 fib6_repair_tree(info->nl_net, fn);
 895         dst_free(&rt->dst);
 896         return err;
 897 #endif
 898 }
 899
 900 /*
 901  *      Routing tree lookup
 902  *
 903  */
 904
 905 struct lookup_args {
 906         int                     offset;         /* key offset on rt6_info       */
 907         const struct in6_addr   *addr;          /* search key                   */
 908 };
 909
 910 static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 911                                         struct lookup_args *args)
 912 {
 913         struct fib6_node *fn;
 914         __be32 dir;
 915
 916         if (unlikely(args->offset == 0))
 917                 return NULL;
 918
 919         /*
 920          *      Descend on a tree
 921          */
 922
 923         fn = root;
 924
 925         for (;;) {
 926                 struct fib6_node *next;
 927
 928                 dir = addr_bit_set(args->addr, fn->fn_bit);
 929
 930                 next = dir ? fn->right : fn->left;
 931
 932                 if (next) {
 933                         fn = next;
 934                         continue;
 935                 }
 936                 break;
 937         }
 938
 939         while (fn) {
 940                 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
 941                         struct rt6key *key;
 942
 943                         key = (struct rt6key *) ((u8 *) fn->leaf +
 944                                                  args->offset);
 945
 946                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 947 #ifdef CONFIG_IPV6_SUBTREES
 948                                 if (fn->subtree)
 949                                         fn = fib6_lookup_1(fn->subtree, args + 1);
 950 #endif
 951                                 if (!fn || fn->fn_flags & RTN_RTINFO)
 952                                         return fn;
 953                         }
 954                 }
 955
 956                 if (fn->fn_flags & RTN_ROOT)
 957                         break;
 958
 959                 fn = fn->parent;
 960         }
 961
 962         return NULL;
 963 }
 964
 965 struct fib6_node * fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
 966                                const struct in6_addr *saddr)
 967 {
 968         struct fib6_node *fn;
 969         struct lookup_args args[] = {
 970                 {
 971                         .offset = offsetof(struct rt6_info, rt6i_dst),
 972                         .addr = daddr,
 973                 },
 974 #ifdef CONFIG_IPV6_SUBTREES
 975                 {
 976                         .offset = offsetof(struct rt6_info, rt6i_src),
 977                         .addr = saddr,
 978                 },
 979 #endif
 980                 {
 981                         .offset = 0,    /* sentinel */
 982                 }
 983         };
 984
 985         fn = fib6_lookup_1(root, daddr ? args : args + 1);
 986         if (!fn || fn->fn_flags & RTN_TL_ROOT)
 987                 fn = root;
 988
 989         return fn;
 990 }
 991
 992 /*
 993  *      Get node with specified destination prefix (and source prefix,
 994  *      if subtrees are used)
 995  */
 996
 997
 998 static struct fib6_node * fib6_locate_1(struct fib6_node *root,
 999                                         const struct in6_addr *addr,
1000                                         int plen, int offset)
1001 {
1002         struct fib6_node *fn;
1003
1004         for (fn = root; fn ; ) {
1005                 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1006
1007                 /*
1008                  *      Prefix match
1009                  */
1010                 if (plen < fn->fn_bit ||
1011                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1012                         return NULL;
1013
1014                 if (plen == fn->fn_bit)
1015                         return fn;
1016
1017                 /*
1018                  *      We have more bits to go
1019                  */
1020                 if (addr_bit_set(addr, fn->fn_bit))
1021                         fn = fn->right;
1022                 else
1023                         fn = fn->left;
1024         }
1025         return NULL;
1026 }
1027
1028 struct fib6_node * fib6_locate(struct fib6_node *root,
1029                                const struct in6_addr *daddr, int dst_len,
1030                                const struct in6_addr *saddr, int src_len)
1031 {
1032         struct fib6_node *fn;
1033
1034         fn = fib6_locate_1(root, daddr, dst_len,
1035                            offsetof(struct rt6_info, rt6i_dst));
1036
1037 #ifdef CONFIG_IPV6_SUBTREES
1038         if (src_len) {
1039                 WARN_ON(saddr == NULL);
1040                 if (fn && fn->subtree)
1041                         fn = fib6_locate_1(fn->subtree, saddr, src_len,
1042                                            offsetof(struct rt6_info, rt6i_src));
1043         }
1044 #endif
1045
1046         if (fn && fn->fn_flags & RTN_RTINFO)
1047                 return fn;
1048
1049         return NULL;
1050 }
1051
1052
1053 /*
1054  *      Deletion
1055  *
1056  */
1057
1058 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1059 {
1060         if (fn->fn_flags & RTN_ROOT)
1061                 return net->ipv6.ip6_null_entry;
1062
1063         while (fn) {
1064                 if (fn->left)
1065                         return fn->left->leaf;
1066                 if (fn->right)
1067                         return fn->right->leaf;
1068
1069                 fn = FIB6_SUBTREE(fn);
1070         }
1071         return NULL;
1072 }
1073
1074 /*
1075  *      Called to trim the tree of intermediate nodes when possible. "fn"
1076  *      is the node we want to try and remove.
1077  */
1078
1079 static struct fib6_node *fib6_repair_tree(struct net *net,
1080                                            struct fib6_node *fn)
1081 {
1082         int children;
1083         int nstate;
1084         struct fib6_node *child, *pn;
1085         struct fib6_walker_t *w;
1086         int iter = 0;
1087
1088         for (;;) {
1089                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1090                 iter++;
1091
1092                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1093                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1094                 WARN_ON(fn->leaf != NULL);
1095
1096                 children = 0;
1097                 child = NULL;
1098                 if (fn->right) child = fn->right, children |= 1;
1099                 if (fn->left) child = fn->left, children |= 2;
1100
1101                 if (children == 3 || FIB6_SUBTREE(fn)
1102 #ifdef CONFIG_IPV6_SUBTREES
1103                     /* Subtree root (i.e. fn) may have one child */
1104                     || (children && fn->fn_flags & RTN_ROOT)
1105 #endif
1106                     ) {
1107                         fn->leaf = fib6_find_prefix(net, fn);
1108 #if RT6_DEBUG >= 2
1109                         if (!fn->leaf) {
1110                                 WARN_ON(!fn->leaf);
1111                                 fn->leaf = net->ipv6.ip6_null_entry;
1112                         }
1113 #endif
1114                         atomic_inc(&fn->leaf->rt6i_ref);
1115                         return fn->parent;
1116                 }
1117
1118                 pn = fn->parent;
1119 #ifdef CONFIG_IPV6_SUBTREES
1120                 if (FIB6_SUBTREE(pn) == fn) {
1121                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1122                         FIB6_SUBTREE(pn) = NULL;
1123                         nstate = FWS_L;
1124                 } else {
1125                         WARN_ON(fn->fn_flags & RTN_ROOT);
1126 #endif
1127                         if (pn->right == fn) pn->right = child;
1128                         else if (pn->left == fn) pn->left = child;
1129 #if RT6_DEBUG >= 2
1130                         else
1131                                 WARN_ON(1);
1132 #endif
1133                         if (child)
1134                                 child->parent = pn;
1135                         nstate = FWS_R;
1136 #ifdef CONFIG_IPV6_SUBTREES
1137                 }
1138 #endif
1139
1140                 read_lock(&fib6_walker_lock);
1141                 FOR_WALKERS(w) {
1142                         if (!child) {
1143                                 if (w->root == fn) {
1144                                         w->root = w->node = NULL;
1145                                         RT6_TRACE("W %p adjusted by delroot 1\n", w);
1146                                 } else if (w->node == fn) {
1147                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1148                                         w->node = pn;
1149                                         w->state = nstate;
1150                                 }
1151                         } else {
1152                                 if (w->root == fn) {
1153                                         w->root = child;
1154                                         RT6_TRACE("W %p adjusted by delroot 2\n", w);
1155                                 }
1156                                 if (w->node == fn) {
1157                                         w->node = child;
1158                                         if (children&2) {
1159                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1160                                                 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1161                                         } else {
1162                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1163                                                 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1164                                         }
1165                                 }
1166                         }
1167                 }
1168                 read_unlock(&fib6_walker_lock);
1169
1170                 node_free(fn);
1171                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1172                         return pn;
1173
1174                 rt6_release(pn->leaf);
1175                 pn->leaf = NULL;
1176                 fn = pn;
1177         }
1178 }
1179
1180 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1181                            struct nl_info *info)
1182 {
1183         struct fib6_walker_t *w;
1184         struct rt6_info *rt = *rtp;
1185         struct net *net = info->nl_net;
1186
1187         RT6_TRACE("fib6_del_route\n");
1188
1189         /* Unlink it */
1190         *rtp = rt->dst.rt6_next;
1191         rt->rt6i_node = NULL;
1192         net->ipv6.rt6_stats->fib_rt_entries--;
1193         net->ipv6.rt6_stats->fib_discarded_routes++;
1194
1195         /* Reset round-robin state, if necessary */
1196         if (fn->rr_ptr == rt)
1197                 fn->rr_ptr = NULL;
1198
1199         /* Adjust walkers */
1200         read_lock(&fib6_walker_lock);
1201         FOR_WALKERS(w) {
1202                 if (w->state == FWS_C && w->leaf == rt) {
1203                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1204                         w->leaf = rt->dst.rt6_next;
1205                         if (!w->leaf)
1206                                 w->state = FWS_U;
1207                 }
1208         }
1209         read_unlock(&fib6_walker_lock);
1210
1211         rt->dst.rt6_next = NULL;
1212
1213         /* If it was last route, expunge its radix tree node */
1214         if (!fn->leaf) {
1215                 fn->fn_flags &= ~RTN_RTINFO;
1216                 net->ipv6.rt6_stats->fib_route_nodes--;
1217                 fn = fib6_repair_tree(net, fn);
1218         }
1219
1220         if (atomic_read(&rt->rt6i_ref) != 1) {
1221                 /* This route is used as dummy address holder in some split
1222                  * nodes. It is not leaked, but it still holds other resources,
1223                  * which must be released in time. So, scan ascendant nodes
1224                  * and replace dummy references to this route with references
1225                  * to still alive ones.
1226                  */
1227                 while (fn) {
1228                         if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
1229                                 fn->leaf = fib6_find_prefix(net, fn);
1230                                 atomic_inc(&fn->leaf->rt6i_ref);
1231                                 rt6_release(rt);
1232                         }
1233                         fn = fn->parent;
1234                 }
1235                 /* No more references are possible at this point. */
1236                 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1237         }
1238
1239         inet6_rt_notify(RTM_DELROUTE, rt, info);
1240         rt6_release(rt);
1241 }
1242
1243 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1244 {
1245         struct net *net = info->nl_net;
1246         struct fib6_node *fn = rt->rt6i_node;
1247         struct rt6_info **rtp;
1248
1249 #if RT6_DEBUG >= 2
1250         if (rt->dst.obsolete>0) {
1251                 WARN_ON(fn != NULL);
1252                 return -ENOENT;
1253         }
1254 #endif
1255         if (!fn || rt == net->ipv6.ip6_null_entry)
1256                 return -ENOENT;
1257
1258         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1259
1260         if (!(rt->rt6i_flags & RTF_CACHE)) {
1261                 struct fib6_node *pn = fn;
1262 #ifdef CONFIG_IPV6_SUBTREES
1263                 /* clones of this route might be in another subtree */
1264                 if (rt->rt6i_src.plen) {
1265                         while (!(pn->fn_flags & RTN_ROOT))
1266                                 pn = pn->parent;
1267                         pn = pn->parent;
1268                 }
1269 #endif
1270                 fib6_prune_clones(info->nl_net, pn, rt);
1271         }
1272
1273         /*
1274          *      Walk the leaf entries looking for ourself
1275          */
1276
1277         for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1278                 if (*rtp == rt) {
1279                         fib6_del_route(fn, rtp, info);
1280                         return 0;
1281                 }
1282         }
1283         return -ENOENT;
1284 }
1285
1286 /*
1287  *      Tree traversal function.
1288  *
1289  *      Certainly, it is not interrupt safe.
1290  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1291  *      It means, that we can modify tree during walking
1292  *      and use this function for garbage collection, clone pruning,
1293  *      cleaning tree when a device goes down etc. etc.
1294  *
1295  *      It guarantees that every node will be traversed,
1296  *      and that it will be traversed only once.
1297  *
1298  *      Callback function w->func may return:
1299  *      0 -> continue walking.
1300  *      positive value -> walking is suspended (used by tree dumps,
1301  *      and probably by gc, if it will be split to several slices)
1302  *      negative value -> terminate walking.
1303  *
1304  *      The function itself returns:
1305  *      0   -> walk is complete.
1306  *      >0  -> walk is incomplete (i.e. suspended)
1307  *      <0  -> walk is terminated by an error.
1308  */
1309
1310 static int fib6_walk_continue(struct fib6_walker_t *w)
1311 {
1312         struct fib6_node *fn, *pn;
1313
1314         for (;;) {
1315                 fn = w->node;
1316                 if (!fn)
1317                         return 0;
1318
1319                 if (w->prune && fn != w->root &&
1320                     fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1321                         w->state = FWS_C;
1322                         w->leaf = fn->leaf;
1323                 }
1324                 switch (w->state) {
1325 #ifdef CONFIG_IPV6_SUBTREES
1326                 case FWS_S:
1327                         if (FIB6_SUBTREE(fn)) {
1328                                 w->node = FIB6_SUBTREE(fn);
1329                                 continue;
1330                         }
1331                         w->state = FWS_L;
1332 #endif
1333                 case FWS_L:
1334                         if (fn->left) {
1335                                 w->node = fn->left;
1336                                 w->state = FWS_INIT;
1337                                 continue;
1338                         }
1339                         w->state = FWS_R;
1340                 case FWS_R:
1341                         if (fn->right) {
1342                                 w->node = fn->right;
1343                                 w->state = FWS_INIT;
1344                                 continue;
1345                         }
1346                         w->state = FWS_C;
1347                         w->leaf = fn->leaf;
1348                 case FWS_C:
1349                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1350                                 int err;
1351
1352                                 if (w->count < w->skip) {
1353                                         w->count++;
1354                                         continue;
1355                                 }
1356
1357                                 err = w->func(w);
1358                                 if (err)
1359                                         return err;
1360
1361                                 w->count++;
1362                                 continue;
1363                         }
1364                         w->state = FWS_U;
1365                 case FWS_U:
1366                         if (fn == w->root)
1367                                 return 0;
1368                         pn = fn->parent;
1369                         w->node = pn;
1370 #ifdef CONFIG_IPV6_SUBTREES
1371                         if (FIB6_SUBTREE(pn) == fn) {
1372                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1373                                 w->state = FWS_L;
1374                                 continue;
1375                         }
1376 #endif
1377                         if (pn->left == fn) {
1378                                 w->state = FWS_R;
1379                                 continue;
1380                         }
1381                         if (pn->right == fn) {
1382                                 w->state = FWS_C;
1383                                 w->leaf = w->node->leaf;
1384                                 continue;
1385                         }
1386 #if RT6_DEBUG >= 2
1387                         WARN_ON(1);
1388 #endif
1389                 }
1390         }
1391 }
1392
1393 static int fib6_walk(struct fib6_walker_t *w)
1394 {
1395         int res;
1396
1397         w->state = FWS_INIT;
1398         w->node = w->root;
1399
1400         fib6_walker_link(w);
1401         res = fib6_walk_continue(w);
1402         if (res <= 0)
1403                 fib6_walker_unlink(w);
1404         return res;
1405 }
1406
1407 static int fib6_clean_node(struct fib6_walker_t *w)
1408 {
1409         int res;
1410         struct rt6_info *rt;
1411         struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1412         struct nl_info info = {
1413                 .nl_net = c->net,
1414         };
1415
1416         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1417                 res = c->func(rt, c->arg);
1418                 if (res < 0) {
1419                         w->leaf = rt;
1420                         res = fib6_del(rt, &info);
1421                         if (res) {
1422 #if RT6_DEBUG >= 2
1423                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1424                                          __func__, rt, rt->rt6i_node, res);
1425 #endif
1426                                 continue;
1427                         }
1428                         return 0;
1429                 }
1430                 WARN_ON(res != 0);
1431         }
1432         w->leaf = rt;
1433         return 0;
1434 }
1435
1436 /*
1437  *      Convenient frontend to tree walker.
1438  *
1439  *      func is called on each route.
1440  *              It may return -1 -> delete this route.
1441  *                            0  -> continue walking
1442  *
1443  *      prune==1 -> only immediate children of node (certainly,
1444  *      ignoring pure split nodes) will be scanned.
1445  */
1446
1447 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1448                             int (*func)(struct rt6_info *, void *arg),
1449                             int prune, void *arg)
1450 {
1451         struct fib6_cleaner_t c;
1452
1453         c.w.root = root;
1454         c.w.func = fib6_clean_node;
1455         c.w.prune = prune;
1456         c.w.count = 0;
1457         c.w.skip = 0;
1458         c.func = func;
1459         c.arg = arg;
1460         c.net = net;
1461
1462         fib6_walk(&c.w);
1463 }
1464
1465 void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg),
1466                     int prune, void *arg)
1467 {
1468         struct fib6_table *table;
1469         struct hlist_node *node;
1470         struct hlist_head *head;
1471         unsigned int h;
1472
1473         rcu_read_lock();
1474         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1475                 head = &net->ipv6.fib_table_hash[h];
1476                 hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1477                         read_lock_bh(&table->tb6_lock);
1478                         fib6_clean_tree(net, &table->tb6_root,
1479                                         func, prune, arg);
1480                         read_unlock_bh(&table->tb6_lock);
1481                 }
1482         }
1483         rcu_read_unlock();
1484 }
1485 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
1486                     int prune, void *arg)
1487 {
1488         struct fib6_table *table;
1489         struct hlist_node *node;
1490         struct hlist_head *head;
1491         unsigned int h;
1492
1493         rcu_read_lock();
1494         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1495                 head = &net->ipv6.fib_table_hash[h];
1496                 hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1497                         write_lock_bh(&table->tb6_lock);
1498                         fib6_clean_tree(net, &table->tb6_root,
1499                                         func, prune, arg);
1500                         write_unlock_bh(&table->tb6_lock);
1501                 }
1502         }
1503         rcu_read_unlock();
1504 }
1505
1506 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1507 {
1508         if (rt->rt6i_flags & RTF_CACHE) {
1509                 RT6_TRACE("pruning clone %p\n", rt);
1510                 return -1;
1511         }
1512
1513         return 0;
1514 }
1515
1516 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
1517                               struct rt6_info *rt)
1518 {
1519         fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
1520 }
1521
1522 /*
1523  *      Garbage collection
1524  */
1525
1526 static struct fib6_gc_args
1527 {
1528         int                     timeout;
1529         int                     more;
1530 } gc_args;
1531
1532 static int fib6_age(struct rt6_info *rt, void *arg)
1533 {
1534         unsigned long now = jiffies;
1535
1536         /*
1537          *      check addrconf expiration here.
1538          *      Routes are expired even if they are in use.
1539          *
1540          *      Also age clones. Note, that clones are aged out
1541          *      only if they are not in use now.
1542          */
1543
1544         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1545                 if (time_after(now, rt->dst.expires)) {
1546                         RT6_TRACE("expiring %p\n", rt);
1547                         return -1;
1548                 }
1549                 gc_args.more++;
1550         } else if (rt->rt6i_flags & RTF_CACHE) {
1551                 if (atomic_read(&rt->dst.__refcnt) == 0 &&
1552                     time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1553                         RT6_TRACE("aging clone %p\n", rt);
1554                         return -1;
1555                 } else if (rt->rt6i_flags & RTF_GATEWAY) {
1556                         struct neighbour *neigh;
1557                         __u8 neigh_flags = 0;
1558
1559                         neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1560                         if (neigh) {
1561                                 neigh_flags = neigh->flags;
1562                                 neigh_release(neigh);
1563                         }
1564                         if (!(neigh_flags & NTF_ROUTER)) {
1565                                 RT6_TRACE("purging route %p via non-router but gateway\n",
1566                                           rt);
1567                                 return -1;
1568                         }
1569                 }
1570                 gc_args.more++;
1571         }
1572
1573         return 0;
1574 }
1575
1576 static DEFINE_SPINLOCK(fib6_gc_lock);
1577
1578 void fib6_run_gc(unsigned long expires, struct net *net)
1579 {
1580         if (expires != ~0UL) {
1581                 spin_lock_bh(&fib6_gc_lock);
1582                 gc_args.timeout = expires ? (int)expires :
1583                         net->ipv6.sysctl.ip6_rt_gc_interval;
1584         } else {
1585                 if (!spin_trylock_bh(&fib6_gc_lock)) {
1586                         mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1587                         return;
1588                 }
1589                 gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
1590         }
1591
1592         gc_args.more = icmp6_dst_gc();
1593
1594         fib6_clean_all(net, fib6_age, 0, NULL);
1595
1596         if (gc_args.more)
1597                 mod_timer(&net->ipv6.ip6_fib_timer,
1598                           round_jiffies(jiffies
1599                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
1600         else
1601                 del_timer(&net->ipv6.ip6_fib_timer);
1602         spin_unlock_bh(&fib6_gc_lock);
1603 }
1604
1605 static void fib6_gc_timer_cb(unsigned long arg)
1606 {
1607         fib6_run_gc(0, (struct net *)arg);
1608 }
1609
1610 static int __net_init fib6_net_init(struct net *net)
1611 {
1612         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1613
1614         setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1615
1616         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1617         if (!net->ipv6.rt6_stats)
1618                 goto out_timer;
1619
1620         /* Avoid false sharing : Use at least a full cache line */
1621         size = max_t(size_t, size, L1_CACHE_BYTES);
1622
1623         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1624         if (!net->ipv6.fib_table_hash)
1625                 goto out_rt6_stats;
1626
1627         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1628                                           GFP_KERNEL);
1629         if (!net->ipv6.fib6_main_tbl)
1630                 goto out_fib_table_hash;
1631
1632         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1633         net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1634         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1635                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1636
1637 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1638         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1639                                            GFP_KERNEL);
1640         if (!net->ipv6.fib6_local_tbl)
1641                 goto out_fib6_main_tbl;
1642         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1643         net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1644         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1645                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1646 #endif
1647         fib6_tables_init(net);
1648
1649         return 0;
1650
1651 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1652 out_fib6_main_tbl:
1653         kfree(net->ipv6.fib6_main_tbl);
1654 #endif
1655 out_fib_table_hash:
1656         kfree(net->ipv6.fib_table_hash);
1657 out_rt6_stats:
1658         kfree(net->ipv6.rt6_stats);
1659 out_timer:
1660         return -ENOMEM;
1661  }
1662
1663 static void fib6_net_exit(struct net *net)
1664 {
1665         rt6_ifdown(net, NULL);
1666         del_timer_sync(&net->ipv6.ip6_fib_timer);
1667
1668 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1669         kfree(net->ipv6.fib6_local_tbl);
1670 #endif
1671         kfree(net->ipv6.fib6_main_tbl);
1672         kfree(net->ipv6.fib_table_hash);
1673         kfree(net->ipv6.rt6_stats);
1674 }
1675
1676 static struct pernet_operations fib6_net_ops = {
1677         .init = fib6_net_init,
1678         .exit = fib6_net_exit,
1679 };
1680
1681 int __init fib6_init(void)
1682 {
1683         int ret = -ENOMEM;
1684
1685         fib6_node_kmem = kmem_cache_create("fib6_nodes",
1686                                            sizeof(struct fib6_node),
1687                                            0, SLAB_HWCACHE_ALIGN,
1688                                            NULL);
1689         if (!fib6_node_kmem)
1690                 goto out;
1691
1692         ret = register_pernet_subsys(&fib6_net_ops);
1693         if (ret)
1694                 goto out_kmem_cache_create;
1695
1696         ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1697                               NULL);
1698         if (ret)
1699                 goto out_unregister_subsys;
1700 out:
1701         return ret;
1702
1703 out_unregister_subsys:
1704         unregister_pernet_subsys(&fib6_net_ops);
1705 out_kmem_cache_create:
1706         kmem_cache_destroy(fib6_node_kmem);
1707         goto out;
1708 }
1709
1710 void fib6_gc_cleanup(void)
1711 {
1712         unregister_pernet_subsys(&fib6_net_ops);
1713         kmem_cache_destroy(fib6_node_kmem);
1714 }