linux/net/ipv6/ip6_fib.c
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   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
  49static struct kmem_cache * fib6_node_kmem __read_mostly;
  50
  51enum 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
  62struct 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
  70static 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
  78static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
  79                              struct rt6_info *rt);
  80static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
  81static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
  82static int fib6_walk(struct fib6_walker_t *w);
  83static 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
  92static __u32 rt_sernum;
  93
  94static void fib6_gc_timer_cb(unsigned long arg);
  95
  96static LIST_HEAD(fib6_walkers);
  97#define FOR_WALKERS(w) list_for_each_entry(w, &fib6_walkers, lh)
  98
  99static 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
 106static 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}
 112static __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
 136static __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
 150static __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
 159static __inline__ void node_free(struct fib6_node * fn)
 160{
 161        kmem_cache_free(fib6_node_kmem, fn);
 162}
 163
 164static __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
 170static 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
 191static 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
 206struct 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
 223struct 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
 246static 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
 253struct fib6_table *fib6_new_table(struct net *net, u32 id)
 254{
 255        return fib6_get_table(net, id);
 256}
 257
 258struct fib6_table *fib6_get_table(struct net *net, u32 id)
 259{
 260          return net->ipv6.fib6_main_tbl;
 261}
 262
 263struct 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
 269static 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
 276static 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
 294static 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
 310static int fib6_dump_done(struct netlink_callback *cb)
 311{
 312        fib6_dump_end(cb);
 313        return cb->done ? cb->done(cb) : 0;
 314}
 315
 316static 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
 358static 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;
 407next:
 408                        e++;
 409                }
 410        }
 411out:
 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
 430static 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 NULL;
 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
 531insert_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 NULL;
 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 NULL;
 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
 641static 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 (!(iter->rt6i_flags & RTF_EXPIRES))
 676                                        return -EEXIST;
 677                                if (!(rt->rt6i_flags & RTF_EXPIRES))
 678                                        rt6_clean_expires(iter);
 679                                else
 680                                        rt6_set_expires(iter, rt->dst.expires);
 681                                return -EEXIST;
 682                        }
 683                }
 684
 685                if (iter->rt6i_metric > rt->rt6i_metric)
 686                        break;
 687
 688                ins = &iter->dst.rt6_next;
 689        }
 690
 691        /* Reset round-robin state, if necessary */
 692        if (ins == &fn->leaf)
 693                fn->rr_ptr = NULL;
 694
 695        /*
 696         *      insert node
 697         */
 698        if (!replace) {
 699                if (!add)
 700                        pr_warn("NLM_F_CREATE should be set when creating new route\n");
 701
 702add:
 703                rt->dst.rt6_next = iter;
 704                *ins = rt;
 705                rt->rt6i_node = fn;
 706                atomic_inc(&rt->rt6i_ref);
 707                inet6_rt_notify(RTM_NEWROUTE, rt, info);
 708                info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 709
 710                if (!(fn->fn_flags & RTN_RTINFO)) {
 711                        info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 712                        fn->fn_flags |= RTN_RTINFO;
 713                }
 714
 715        } else {
 716                if (!found) {
 717                        if (add)
 718                                goto add;
 719                        pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
 720                        return -ENOENT;
 721                }
 722                *ins = rt;
 723                rt->rt6i_node = fn;
 724                rt->dst.rt6_next = iter->dst.rt6_next;
 725                atomic_inc(&rt->rt6i_ref);
 726                inet6_rt_notify(RTM_NEWROUTE, rt, info);
 727                rt6_release(iter);
 728                if (!(fn->fn_flags & RTN_RTINFO)) {
 729                        info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 730                        fn->fn_flags |= RTN_RTINFO;
 731                }
 732        }
 733
 734        return 0;
 735}
 736
 737static __inline__ void fib6_start_gc(struct net *net, struct rt6_info *rt)
 738{
 739        if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 740            (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 741                mod_timer(&net->ipv6.ip6_fib_timer,
 742                          jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 743}
 744
 745void fib6_force_start_gc(struct net *net)
 746{
 747        if (!timer_pending(&net->ipv6.ip6_fib_timer))
 748                mod_timer(&net->ipv6.ip6_fib_timer,
 749                          jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 750}
 751
 752/*
 753 *      Add routing information to the routing tree.
 754 *      <destination addr>/<source addr>
 755 *      with source addr info in sub-trees
 756 */
 757
 758int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
 759{
 760        struct fib6_node *fn, *pn = NULL;
 761        int err = -ENOMEM;
 762        int allow_create = 1;
 763        int replace_required = 0;
 764
 765        if (info->nlh) {
 766                if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 767                        allow_create = 0;
 768                if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 769                        replace_required = 1;
 770        }
 771        if (!allow_create && !replace_required)
 772                pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 773
 774        fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
 775                        rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst),
 776                        allow_create, replace_required);
 777
 778        if (IS_ERR(fn)) {
 779                err = PTR_ERR(fn);
 780                fn = NULL;
 781        }
 782
 783        if (!fn)
 784                goto out;
 785
 786        pn = fn;
 787
 788#ifdef CONFIG_IPV6_SUBTREES
 789        if (rt->rt6i_src.plen) {
 790                struct fib6_node *sn;
 791
 792                if (!fn->subtree) {
 793                        struct fib6_node *sfn;
 794
 795                        /*
 796                         * Create subtree.
 797                         *
 798                         *              fn[main tree]
 799                         *              |
 800                         *              sfn[subtree root]
 801                         *                 \
 802                         *                  sn[new leaf node]
 803                         */
 804
 805                        /* Create subtree root node */
 806                        sfn = node_alloc();
 807                        if (!sfn)
 808                                goto st_failure;
 809
 810                        sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 811                        atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 812                        sfn->fn_flags = RTN_ROOT;
 813                        sfn->fn_sernum = fib6_new_sernum();
 814
 815                        /* Now add the first leaf node to new subtree */
 816
 817                        sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 818                                        sizeof(struct in6_addr), rt->rt6i_src.plen,
 819                                        offsetof(struct rt6_info, rt6i_src),
 820                                        allow_create, replace_required);
 821
 822                        if (IS_ERR(sn)) {
 823                                err = PTR_ERR(sn);
 824                                sn = NULL;
 825                        }
 826                        if (!sn) {
 827                                /* If it is failed, discard just allocated
 828                                   root, and then (in st_failure) stale node
 829                                   in main tree.
 830                                 */
 831                                node_free(sfn);
 832                                goto st_failure;
 833                        }
 834
 835                        /* Now link new subtree to main tree */
 836                        sfn->parent = fn;
 837                        fn->subtree = sfn;
 838                } else {
 839                        sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 840                                        sizeof(struct in6_addr), rt->rt6i_src.plen,
 841                                        offsetof(struct rt6_info, rt6i_src),
 842                                        allow_create, replace_required);
 843
 844                        if (IS_ERR(sn)) {
 845                                err = PTR_ERR(sn);
 846                                sn = NULL;
 847                        }
 848                        if (!sn)
 849                                goto st_failure;
 850                }
 851
 852                if (!fn->leaf) {
 853                        fn->leaf = rt;
 854                        atomic_inc(&rt->rt6i_ref);
 855                }
 856                fn = sn;
 857        }
 858#endif
 859
 860        err = fib6_add_rt2node(fn, rt, info);
 861        if (!err) {
 862                fib6_start_gc(info->nl_net, rt);
 863                if (!(rt->rt6i_flags & RTF_CACHE))
 864                        fib6_prune_clones(info->nl_net, pn, rt);
 865        }
 866
 867out:
 868        if (err) {
 869#ifdef CONFIG_IPV6_SUBTREES
 870                /*
 871                 * If fib6_add_1 has cleared the old leaf pointer in the
 872                 * super-tree leaf node we have to find a new one for it.
 873                 */
 874                if (pn != fn && pn->leaf == rt) {
 875                        pn->leaf = NULL;
 876                        atomic_dec(&rt->rt6i_ref);
 877                }
 878                if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 879                        pn->leaf = fib6_find_prefix(info->nl_net, pn);
 880#if RT6_DEBUG >= 2
 881                        if (!pn->leaf) {
 882                                WARN_ON(pn->leaf == NULL);
 883                                pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 884                        }
 885#endif
 886                        atomic_inc(&pn->leaf->rt6i_ref);
 887                }
 888#endif
 889                dst_free(&rt->dst);
 890        }
 891        return err;
 892
 893#ifdef CONFIG_IPV6_SUBTREES
 894        /* Subtree creation failed, probably main tree node
 895           is orphan. If it is, shoot it.
 896         */
 897st_failure:
 898        if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 899                fib6_repair_tree(info->nl_net, fn);
 900        dst_free(&rt->dst);
 901        return err;
 902#endif
 903}
 904
 905/*
 906 *      Routing tree lookup
 907 *
 908 */
 909
 910struct lookup_args {
 911        int                     offset;         /* key offset on rt6_info       */
 912        const struct in6_addr   *addr;          /* search key                   */
 913};
 914
 915static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 916                                        struct lookup_args *args)
 917{
 918        struct fib6_node *fn;
 919        __be32 dir;
 920
 921        if (unlikely(args->offset == 0))
 922                return NULL;
 923
 924        /*
 925         *      Descend on a tree
 926         */
 927
 928        fn = root;
 929
 930        for (;;) {
 931                struct fib6_node *next;
 932
 933                dir = addr_bit_set(args->addr, fn->fn_bit);
 934
 935                next = dir ? fn->right : fn->left;
 936
 937                if (next) {
 938                        fn = next;
 939                        continue;
 940                }
 941                break;
 942        }
 943
 944        while (fn) {
 945                if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
 946                        struct rt6key *key;
 947
 948                        key = (struct rt6key *) ((u8 *) fn->leaf +
 949                                                 args->offset);
 950
 951                        if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 952#ifdef CONFIG_IPV6_SUBTREES
 953                                if (fn->subtree)
 954                                        fn = fib6_lookup_1(fn->subtree, args + 1);
 955#endif
 956                                if (!fn || fn->fn_flags & RTN_RTINFO)
 957                                        return fn;
 958                        }
 959                }
 960
 961                if (fn->fn_flags & RTN_ROOT)
 962                        break;
 963
 964                fn = fn->parent;
 965        }
 966
 967        return NULL;
 968}
 969
 970struct fib6_node * fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
 971                               const struct in6_addr *saddr)
 972{
 973        struct fib6_node *fn;
 974        struct lookup_args args[] = {
 975                {
 976                        .offset = offsetof(struct rt6_info, rt6i_dst),
 977                        .addr = daddr,
 978                },
 979#ifdef CONFIG_IPV6_SUBTREES
 980                {
 981                        .offset = offsetof(struct rt6_info, rt6i_src),
 982                        .addr = saddr,
 983                },
 984#endif
 985                {
 986                        .offset = 0,    /* sentinel */
 987                }
 988        };
 989
 990        fn = fib6_lookup_1(root, daddr ? args : args + 1);
 991        if (!fn || fn->fn_flags & RTN_TL_ROOT)
 992                fn = root;
 993
 994        return fn;
 995}
 996
 997/*
 998 *      Get node with specified destination prefix (and source prefix,
 999 *      if subtrees are used)
1000 */
1001
1002
1003static struct fib6_node * fib6_locate_1(struct fib6_node *root,
1004                                        const struct in6_addr *addr,
1005                                        int plen, int offset)
1006{
1007        struct fib6_node *fn;
1008
1009        for (fn = root; fn ; ) {
1010                struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1011
1012                /*
1013                 *      Prefix match
1014                 */
1015                if (plen < fn->fn_bit ||
1016                    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1017                        return NULL;
1018
1019                if (plen == fn->fn_bit)
1020                        return fn;
1021
1022                /*
1023                 *      We have more bits to go
1024                 */
1025                if (addr_bit_set(addr, fn->fn_bit))
1026                        fn = fn->right;
1027                else
1028                        fn = fn->left;
1029        }
1030        return NULL;
1031}
1032
1033struct fib6_node * fib6_locate(struct fib6_node *root,
1034                               const struct in6_addr *daddr, int dst_len,
1035                               const struct in6_addr *saddr, int src_len)
1036{
1037        struct fib6_node *fn;
1038
1039        fn = fib6_locate_1(root, daddr, dst_len,
1040                           offsetof(struct rt6_info, rt6i_dst));
1041
1042#ifdef CONFIG_IPV6_SUBTREES
1043        if (src_len) {
1044                WARN_ON(saddr == NULL);
1045                if (fn && fn->subtree)
1046                        fn = fib6_locate_1(fn->subtree, saddr, src_len,
1047                                           offsetof(struct rt6_info, rt6i_src));
1048        }
1049#endif
1050
1051        if (fn && fn->fn_flags & RTN_RTINFO)
1052                return fn;
1053
1054        return NULL;
1055}
1056
1057
1058/*
1059 *      Deletion
1060 *
1061 */
1062
1063static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1064{
1065        if (fn->fn_flags & RTN_ROOT)
1066                return net->ipv6.ip6_null_entry;
1067
1068        while (fn) {
1069                if (fn->left)
1070                        return fn->left->leaf;
1071                if (fn->right)
1072                        return fn->right->leaf;
1073
1074                fn = FIB6_SUBTREE(fn);
1075        }
1076        return NULL;
1077}
1078
1079/*
1080 *      Called to trim the tree of intermediate nodes when possible. "fn"
1081 *      is the node we want to try and remove.
1082 */
1083
1084static struct fib6_node *fib6_repair_tree(struct net *net,
1085                                           struct fib6_node *fn)
1086{
1087        int children;
1088        int nstate;
1089        struct fib6_node *child, *pn;
1090        struct fib6_walker_t *w;
1091        int iter = 0;
1092
1093        for (;;) {
1094                RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1095                iter++;
1096
1097                WARN_ON(fn->fn_flags & RTN_RTINFO);
1098                WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1099                WARN_ON(fn->leaf != NULL);
1100
1101                children = 0;
1102                child = NULL;
1103                if (fn->right) child = fn->right, children |= 1;
1104                if (fn->left) child = fn->left, children |= 2;
1105
1106                if (children == 3 || FIB6_SUBTREE(fn)
1107#ifdef CONFIG_IPV6_SUBTREES
1108                    /* Subtree root (i.e. fn) may have one child */
1109                    || (children && fn->fn_flags & RTN_ROOT)
1110#endif
1111                    ) {
1112                        fn->leaf = fib6_find_prefix(net, fn);
1113#if RT6_DEBUG >= 2
1114                        if (!fn->leaf) {
1115                                WARN_ON(!fn->leaf);
1116                                fn->leaf = net->ipv6.ip6_null_entry;
1117                        }
1118#endif
1119                        atomic_inc(&fn->leaf->rt6i_ref);
1120                        return fn->parent;
1121                }
1122
1123                pn = fn->parent;
1124#ifdef CONFIG_IPV6_SUBTREES
1125                if (FIB6_SUBTREE(pn) == fn) {
1126                        WARN_ON(!(fn->fn_flags & RTN_ROOT));
1127                        FIB6_SUBTREE(pn) = NULL;
1128                        nstate = FWS_L;
1129                } else {
1130                        WARN_ON(fn->fn_flags & RTN_ROOT);
1131#endif
1132                        if (pn->right == fn) pn->right = child;
1133                        else if (pn->left == fn) pn->left = child;
1134#if RT6_DEBUG >= 2
1135                        else
1136                                WARN_ON(1);
1137#endif
1138                        if (child)
1139                                child->parent = pn;
1140                        nstate = FWS_R;
1141#ifdef CONFIG_IPV6_SUBTREES
1142                }
1143#endif
1144
1145                read_lock(&fib6_walker_lock);
1146                FOR_WALKERS(w) {
1147                        if (!child) {
1148                                if (w->root == fn) {
1149                                        w->root = w->node = NULL;
1150                                        RT6_TRACE("W %p adjusted by delroot 1\n", w);
1151                                } else if (w->node == fn) {
1152                                        RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1153                                        w->node = pn;
1154                                        w->state = nstate;
1155                                }
1156                        } else {
1157                                if (w->root == fn) {
1158                                        w->root = child;
1159                                        RT6_TRACE("W %p adjusted by delroot 2\n", w);
1160                                }
1161                                if (w->node == fn) {
1162                                        w->node = child;
1163                                        if (children&2) {
1164                                                RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1165                                                w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1166                                        } else {
1167                                                RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1168                                                w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1169                                        }
1170                                }
1171                        }
1172                }
1173                read_unlock(&fib6_walker_lock);
1174
1175                node_free(fn);
1176                if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1177                        return pn;
1178
1179                rt6_release(pn->leaf);
1180                pn->leaf = NULL;
1181                fn = pn;
1182        }
1183}
1184
1185static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1186                           struct nl_info *info)
1187{
1188        struct fib6_walker_t *w;
1189        struct rt6_info *rt = *rtp;
1190        struct net *net = info->nl_net;
1191
1192        RT6_TRACE("fib6_del_route\n");
1193
1194        /* Unlink it */
1195        *rtp = rt->dst.rt6_next;
1196        rt->rt6i_node = NULL;
1197        net->ipv6.rt6_stats->fib_rt_entries--;
1198        net->ipv6.rt6_stats->fib_discarded_routes++;
1199
1200        /* Reset round-robin state, if necessary */
1201        if (fn->rr_ptr == rt)
1202                fn->rr_ptr = NULL;
1203
1204        /* Adjust walkers */
1205        read_lock(&fib6_walker_lock);
1206        FOR_WALKERS(w) {
1207                if (w->state == FWS_C && w->leaf == rt) {
1208                        RT6_TRACE("walker %p adjusted by delroute\n", w);
1209                        w->leaf = rt->dst.rt6_next;
1210                        if (!w->leaf)
1211                                w->state = FWS_U;
1212                }
1213        }
1214        read_unlock(&fib6_walker_lock);
1215
1216        rt->dst.rt6_next = NULL;
1217
1218        /* If it was last route, expunge its radix tree node */
1219        if (!fn->leaf) {
1220                fn->fn_flags &= ~RTN_RTINFO;
1221                net->ipv6.rt6_stats->fib_route_nodes--;
1222                fn = fib6_repair_tree(net, fn);
1223        }
1224
1225        if (atomic_read(&rt->rt6i_ref) != 1) {
1226                /* This route is used as dummy address holder in some split
1227                 * nodes. It is not leaked, but it still holds other resources,
1228                 * which must be released in time. So, scan ascendant nodes
1229                 * and replace dummy references to this route with references
1230                 * to still alive ones.
1231                 */
1232                while (fn) {
1233                        if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
1234                                fn->leaf = fib6_find_prefix(net, fn);
1235                                atomic_inc(&fn->leaf->rt6i_ref);
1236                                rt6_release(rt);
1237                        }
1238                        fn = fn->parent;
1239                }
1240                /* No more references are possible at this point. */
1241                BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1242        }
1243
1244        inet6_rt_notify(RTM_DELROUTE, rt, info);
1245        rt6_release(rt);
1246}
1247
1248int fib6_del(struct rt6_info *rt, struct nl_info *info)
1249{
1250        struct net *net = info->nl_net;
1251        struct fib6_node *fn = rt->rt6i_node;
1252        struct rt6_info **rtp;
1253
1254#if RT6_DEBUG >= 2
1255        if (rt->dst.obsolete>0) {
1256                WARN_ON(fn != NULL);
1257                return -ENOENT;
1258        }
1259#endif
1260        if (!fn || rt == net->ipv6.ip6_null_entry)
1261                return -ENOENT;
1262
1263        WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1264
1265        if (!(rt->rt6i_flags & RTF_CACHE)) {
1266                struct fib6_node *pn = fn;
1267#ifdef CONFIG_IPV6_SUBTREES
1268                /* clones of this route might be in another subtree */
1269                if (rt->rt6i_src.plen) {
1270                        while (!(pn->fn_flags & RTN_ROOT))
1271                                pn = pn->parent;
1272                        pn = pn->parent;
1273                }
1274#endif
1275                fib6_prune_clones(info->nl_net, pn, rt);
1276        }
1277
1278        /*
1279         *      Walk the leaf entries looking for ourself
1280         */
1281
1282        for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1283                if (*rtp == rt) {
1284                        fib6_del_route(fn, rtp, info);
1285                        return 0;
1286                }
1287        }
1288        return -ENOENT;
1289}
1290
1291/*
1292 *      Tree traversal function.
1293 *
1294 *      Certainly, it is not interrupt safe.
1295 *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1296 *      It means, that we can modify tree during walking
1297 *      and use this function for garbage collection, clone pruning,
1298 *      cleaning tree when a device goes down etc. etc.
1299 *
1300 *      It guarantees that every node will be traversed,
1301 *      and that it will be traversed only once.
1302 *
1303 *      Callback function w->func may return:
1304 *      0 -> continue walking.
1305 *      positive value -> walking is suspended (used by tree dumps,
1306 *      and probably by gc, if it will be split to several slices)
1307 *      negative value -> terminate walking.
1308 *
1309 *      The function itself returns:
1310 *      0   -> walk is complete.
1311 *      >0  -> walk is incomplete (i.e. suspended)
1312 *      <0  -> walk is terminated by an error.
1313 */
1314
1315static int fib6_walk_continue(struct fib6_walker_t *w)
1316{
1317        struct fib6_node *fn, *pn;
1318
1319        for (;;) {
1320                fn = w->node;
1321                if (!fn)
1322                        return 0;
1323
1324                if (w->prune && fn != w->root &&
1325                    fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1326                        w->state = FWS_C;
1327                        w->leaf = fn->leaf;
1328                }
1329                switch (w->state) {
1330#ifdef CONFIG_IPV6_SUBTREES
1331                case FWS_S:
1332                        if (FIB6_SUBTREE(fn)) {
1333                                w->node = FIB6_SUBTREE(fn);
1334                                continue;
1335                        }
1336                        w->state = FWS_L;
1337#endif
1338                case FWS_L:
1339                        if (fn->left) {
1340                                w->node = fn->left;
1341                                w->state = FWS_INIT;
1342                                continue;
1343                        }
1344                        w->state = FWS_R;
1345                case FWS_R:
1346                        if (fn->right) {
1347                                w->node = fn->right;
1348                                w->state = FWS_INIT;
1349                                continue;
1350                        }
1351                        w->state = FWS_C;
1352                        w->leaf = fn->leaf;
1353                case FWS_C:
1354                        if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1355                                int err;
1356
1357                                if (w->skip) {
1358                                        w->skip--;
1359                                        continue;
1360                                }
1361
1362                                err = w->func(w);
1363                                if (err)
1364                                        return err;
1365
1366                                w->count++;
1367                                continue;
1368                        }
1369                        w->state = FWS_U;
1370                case FWS_U:
1371                        if (fn == w->root)
1372                                return 0;
1373                        pn = fn->parent;
1374                        w->node = pn;
1375#ifdef CONFIG_IPV6_SUBTREES
1376                        if (FIB6_SUBTREE(pn) == fn) {
1377                                WARN_ON(!(fn->fn_flags & RTN_ROOT));
1378                                w->state = FWS_L;
1379                                continue;
1380                        }
1381#endif
1382                        if (pn->left == fn) {
1383                                w->state = FWS_R;
1384                                continue;
1385                        }
1386                        if (pn->right == fn) {
1387                                w->state = FWS_C;
1388                                w->leaf = w->node->leaf;
1389                                continue;
1390                        }
1391#if RT6_DEBUG >= 2
1392                        WARN_ON(1);
1393#endif
1394                }
1395        }
1396}
1397
1398static int fib6_walk(struct fib6_walker_t *w)
1399{
1400        int res;
1401
1402        w->state = FWS_INIT;
1403        w->node = w->root;
1404
1405        fib6_walker_link(w);
1406        res = fib6_walk_continue(w);
1407        if (res <= 0)
1408                fib6_walker_unlink(w);
1409        return res;
1410}
1411
1412static int fib6_clean_node(struct fib6_walker_t *w)
1413{
1414        int res;
1415        struct rt6_info *rt;
1416        struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1417        struct nl_info info = {
1418                .nl_net = c->net,
1419        };
1420
1421        for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1422                res = c->func(rt, c->arg);
1423                if (res < 0) {
1424                        w->leaf = rt;
1425                        res = fib6_del(rt, &info);
1426                        if (res) {
1427#if RT6_DEBUG >= 2
1428                                pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1429                                         __func__, rt, rt->rt6i_node, res);
1430#endif
1431                                continue;
1432                        }
1433                        return 0;
1434                }
1435                WARN_ON(res != 0);
1436        }
1437        w->leaf = rt;
1438        return 0;
1439}
1440
1441/*
1442 *      Convenient frontend to tree walker.
1443 *
1444 *      func is called on each route.
1445 *              It may return -1 -> delete this route.
1446 *                            0  -> continue walking
1447 *
1448 *      prune==1 -> only immediate children of node (certainly,
1449 *      ignoring pure split nodes) will be scanned.
1450 */
1451
1452static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1453                            int (*func)(struct rt6_info *, void *arg),
1454                            int prune, void *arg)
1455{
1456        struct fib6_cleaner_t c;
1457
1458        c.w.root = root;
1459        c.w.func = fib6_clean_node;
1460        c.w.prune = prune;
1461        c.w.count = 0;
1462        c.w.skip = 0;
1463        c.func = func;
1464        c.arg = arg;
1465        c.net = net;
1466
1467        fib6_walk(&c.w);
1468}
1469
1470void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg),
1471                    int prune, void *arg)
1472{
1473        struct fib6_table *table;
1474        struct hlist_node *node;
1475        struct hlist_head *head;
1476        unsigned int h;
1477
1478        rcu_read_lock();
1479        for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1480                head = &net->ipv6.fib_table_hash[h];
1481                hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1482                        read_lock_bh(&table->tb6_lock);
1483                        fib6_clean_tree(net, &table->tb6_root,
1484                                        func, prune, arg);
1485                        read_unlock_bh(&table->tb6_lock);
1486                }
1487        }
1488        rcu_read_unlock();
1489}
1490void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
1491                    int prune, void *arg)
1492{
1493        struct fib6_table *table;
1494        struct hlist_node *node;
1495        struct hlist_head *head;
1496        unsigned int h;
1497
1498        rcu_read_lock();
1499        for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1500                head = &net->ipv6.fib_table_hash[h];
1501                hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1502                        write_lock_bh(&table->tb6_lock);
1503                        fib6_clean_tree(net, &table->tb6_root,
1504                                        func, prune, arg);
1505                        write_unlock_bh(&table->tb6_lock);
1506                }
1507        }
1508        rcu_read_unlock();
1509}
1510
1511static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1512{
1513        if (rt->rt6i_flags & RTF_CACHE) {
1514                RT6_TRACE("pruning clone %p\n", rt);
1515                return -1;
1516        }
1517
1518        return 0;
1519}
1520
1521static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
1522                              struct rt6_info *rt)
1523{
1524        fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
1525}
1526
1527/*
1528 *      Garbage collection
1529 */
1530
1531static struct fib6_gc_args
1532{
1533        int                     timeout;
1534        int                     more;
1535} gc_args;
1536
1537static int fib6_age(struct rt6_info *rt, void *arg)
1538{
1539        unsigned long now = jiffies;
1540
1541        /*
1542         *      check addrconf expiration here.
1543         *      Routes are expired even if they are in use.
1544         *
1545         *      Also age clones. Note, that clones are aged out
1546         *      only if they are not in use now.
1547         */
1548
1549        if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1550                if (time_after(now, rt->dst.expires)) {
1551                        RT6_TRACE("expiring %p\n", rt);
1552                        return -1;
1553                }
1554                gc_args.more++;
1555        } else if (rt->rt6i_flags & RTF_CACHE) {
1556                if (atomic_read(&rt->dst.__refcnt) == 0 &&
1557                    time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1558                        RT6_TRACE("aging clone %p\n", rt);
1559                        return -1;
1560                } else if (rt->rt6i_flags & RTF_GATEWAY) {
1561                        struct neighbour *neigh;
1562                        __u8 neigh_flags = 0;
1563
1564                        neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1565                        if (neigh) {
1566                                neigh_flags = neigh->flags;
1567                                neigh_release(neigh);
1568                        }
1569                        if (!(neigh_flags & NTF_ROUTER)) {
1570                                RT6_TRACE("purging route %p via non-router but gateway\n",
1571                                          rt);
1572                                return -1;
1573                        }
1574                }
1575                gc_args.more++;
1576        }
1577
1578        return 0;
1579}
1580
1581static DEFINE_SPINLOCK(fib6_gc_lock);
1582
1583void fib6_run_gc(unsigned long expires, struct net *net)
1584{
1585        if (expires != ~0UL) {
1586                spin_lock_bh(&fib6_gc_lock);
1587                gc_args.timeout = expires ? (int)expires :
1588                        net->ipv6.sysctl.ip6_rt_gc_interval;
1589        } else {
1590                if (!spin_trylock_bh(&fib6_gc_lock)) {
1591                        mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1592                        return;
1593                }
1594                gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
1595        }
1596
1597        gc_args.more = icmp6_dst_gc();
1598
1599        fib6_clean_all(net, fib6_age, 0, NULL);
1600
1601        if (gc_args.more)
1602                mod_timer(&net->ipv6.ip6_fib_timer,
1603                          round_jiffies(jiffies
1604                                        + net->ipv6.sysctl.ip6_rt_gc_interval));
1605        else
1606                del_timer(&net->ipv6.ip6_fib_timer);
1607        spin_unlock_bh(&fib6_gc_lock);
1608}
1609
1610static void fib6_gc_timer_cb(unsigned long arg)
1611{
1612        fib6_run_gc(0, (struct net *)arg);
1613}
1614
1615static int __net_init fib6_net_init(struct net *net)
1616{
1617        size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1618
1619        setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1620
1621        net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1622        if (!net->ipv6.rt6_stats)
1623                goto out_timer;
1624
1625        /* Avoid false sharing : Use at least a full cache line */
1626        size = max_t(size_t, size, L1_CACHE_BYTES);
1627
1628        net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1629        if (!net->ipv6.fib_table_hash)
1630                goto out_rt6_stats;
1631
1632        net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1633                                          GFP_KERNEL);
1634        if (!net->ipv6.fib6_main_tbl)
1635                goto out_fib_table_hash;
1636
1637        net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1638        net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1639        net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1640                RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1641        inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1642
1643#ifdef CONFIG_IPV6_MULTIPLE_TABLES
1644        net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1645                                           GFP_KERNEL);
1646        if (!net->ipv6.fib6_local_tbl)
1647                goto out_fib6_main_tbl;
1648        net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1649        net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1650        net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1651                RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1652        inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1653#endif
1654        fib6_tables_init(net);
1655
1656        return 0;
1657
1658#ifdef CONFIG_IPV6_MULTIPLE_TABLES
1659out_fib6_main_tbl:
1660        kfree(net->ipv6.fib6_main_tbl);
1661#endif
1662out_fib_table_hash:
1663        kfree(net->ipv6.fib_table_hash);
1664out_rt6_stats:
1665        kfree(net->ipv6.rt6_stats);
1666out_timer:
1667        return -ENOMEM;
1668 }
1669
1670static void fib6_net_exit(struct net *net)
1671{
1672        rt6_ifdown(net, NULL);
1673        del_timer_sync(&net->ipv6.ip6_fib_timer);
1674
1675#ifdef CONFIG_IPV6_MULTIPLE_TABLES
1676        inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1677        kfree(net->ipv6.fib6_local_tbl);
1678#endif
1679        inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1680        kfree(net->ipv6.fib6_main_tbl);
1681        kfree(net->ipv6.fib_table_hash);
1682        kfree(net->ipv6.rt6_stats);
1683}
1684
1685static struct pernet_operations fib6_net_ops = {
1686        .init = fib6_net_init,
1687        .exit = fib6_net_exit,
1688};
1689
1690int __init fib6_init(void)
1691{
1692        int ret = -ENOMEM;
1693
1694        fib6_node_kmem = kmem_cache_create("fib6_nodes",
1695                                           sizeof(struct fib6_node),
1696                                           0, SLAB_HWCACHE_ALIGN,
1697                                           NULL);
1698        if (!fib6_node_kmem)
1699                goto out;
1700
1701        ret = register_pernet_subsys(&fib6_net_ops);
1702        if (ret)
1703                goto out_kmem_cache_create;
1704
1705        ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1706                              NULL);
1707        if (ret)
1708                goto out_unregister_subsys;
1709out:
1710        return ret;
1711
1712out_unregister_subsys:
1713        unregister_pernet_subsys(&fib6_net_ops);
1714out_kmem_cache_create:
1715        kmem_cache_destroy(fib6_node_kmem);
1716        goto out;
1717}
1718
1719void fib6_gc_cleanup(void)
1720{
1721        unregister_pernet_subsys(&fib6_net_ops);
1722        kmem_cache_destroy(fib6_node_kmem);
1723}
1724
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