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 ERR_PTR(-ENOMEM);
 518        ln->fn_bit = plen;
 519
 520        ln->parent = pn;
 521        ln->fn_sernum = sernum;
 522
 523        if (dir)
 524                pn->right = ln;
 525        else
 526                pn->left  = ln;
 527
 528        return ln;
 529
 530
 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 ERR_PTR(-ENOMEM);
 565                }
 566
 567                /*
 568                 * new intermediate node.
 569                 * RTN_RTINFO will
 570                 * be off since that an address that chooses one of
 571                 * the branches would not match less specific routes
 572                 * in the other branch
 573                 */
 574
 575                in->fn_bit = bit;
 576
 577                in->parent = pn;
 578                in->leaf = fn->leaf;
 579                atomic_inc(&in->leaf->rt6i_ref);
 580
 581                in->fn_sernum = sernum;
 582
 583                /* update parent pointer */
 584                if (dir)
 585                        pn->right = in;
 586                else
 587                        pn->left  = in;
 588
 589                ln->fn_bit = plen;
 590
 591                ln->parent = in;
 592                fn->parent = in;
 593
 594                ln->fn_sernum = sernum;
 595
 596                if (addr_bit_set(addr, bit)) {
 597                        in->right = ln;
 598                        in->left  = fn;
 599                } else {
 600                        in->left  = ln;
 601                        in->right = fn;
 602                }
 603        } else { /* plen <= bit */
 604
 605                /*
 606                 *              (new leaf node)[ln]
 607                 *                /        \
 608                 *           (old node)[fn] NULL
 609                 */
 610
 611                ln = node_alloc();
 612
 613                if (!ln)
 614                        return ERR_PTR(-ENOMEM);
 615
 616                ln->fn_bit = plen;
 617
 618                ln->parent = pn;
 619
 620                ln->fn_sernum = sernum;
 621
 622                if (dir)
 623                        pn->right = ln;
 624                else
 625                        pn->left  = ln;
 626
 627                if (addr_bit_set(&key->addr, plen))
 628                        ln->right = fn;
 629                else
 630                        ln->left  = fn;
 631
 632                fn->parent = ln;
 633        }
 634        return ln;
 635}
 636
 637/*
 638 *      Insert routing information in a node.
 639 */
 640
 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                goto out;
 781        }
 782
 783        pn = fn;
 784
 785#ifdef CONFIG_IPV6_SUBTREES
 786        if (rt->rt6i_src.plen) {
 787                struct fib6_node *sn;
 788
 789                if (!fn->subtree) {
 790                        struct fib6_node *sfn;
 791
 792                        /*
 793                         * Create subtree.
 794                         *
 795                         *              fn[main tree]
 796                         *              |
 797                         *              sfn[subtree root]
 798                         *                 \
 799                         *                  sn[new leaf node]
 800                         */
 801
 802                        /* Create subtree root node */
 803                        sfn = node_alloc();
 804                        if (!sfn)
 805                                goto st_failure;
 806
 807                        sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 808                        atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 809                        sfn->fn_flags = RTN_ROOT;
 810                        sfn->fn_sernum = fib6_new_sernum();
 811
 812                        /* Now add the first leaf node to new subtree */
 813
 814                        sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 815                                        sizeof(struct in6_addr), rt->rt6i_src.plen,
 816                                        offsetof(struct rt6_info, rt6i_src),
 817                                        allow_create, replace_required);
 818
 819                        if (IS_ERR(sn)) {
 820                                /* If it is failed, discard just allocated
 821                                   root, and then (in st_failure) stale node
 822                                   in main tree.
 823                                 */
 824                                node_free(sfn);
 825                                err = PTR_ERR(sn);
 826                                goto st_failure;
 827                        }
 828
 829                        /* Now link new subtree to main tree */
 830                        sfn->parent = fn;
 831                        fn->subtree = sfn;
 832                } else {
 833                        sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 834                                        sizeof(struct in6_addr), rt->rt6i_src.plen,
 835                                        offsetof(struct rt6_info, rt6i_src),
 836                                        allow_create, replace_required);
 837
 838                        if (IS_ERR(sn)) {
 839                                err = PTR_ERR(sn);
 840                                goto st_failure;
 841                        }
 842                }
 843
 844                if (!fn->leaf) {
 845                        fn->leaf = rt;
 846                        atomic_inc(&rt->rt6i_ref);
 847                }
 848                fn = sn;
 849        }
 850#endif
 851
 852        err = fib6_add_rt2node(fn, rt, info);
 853        if (!err) {
 854                fib6_start_gc(info->nl_net, rt);
 855                if (!(rt->rt6i_flags & RTF_CACHE))
 856                        fib6_prune_clones(info->nl_net, pn, rt);
 857        }
 858
 859out:
 860        if (err) {
 861#ifdef CONFIG_IPV6_SUBTREES
 862                /*
 863                 * If fib6_add_1 has cleared the old leaf pointer in the
 864                 * super-tree leaf node we have to find a new one for it.
 865                 */
 866                if (pn != fn && pn->leaf == rt) {
 867                        pn->leaf = NULL;
 868                        atomic_dec(&rt->rt6i_ref);
 869                }
 870                if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 871                        pn->leaf = fib6_find_prefix(info->nl_net, pn);
 872#if RT6_DEBUG >= 2
 873                        if (!pn->leaf) {
 874                                WARN_ON(pn->leaf == NULL);
 875                                pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 876                        }
 877#endif
 878                        atomic_inc(&pn->leaf->rt6i_ref);
 879                }
 880#endif
 881                dst_free(&rt->dst);
 882        }
 883        return err;
 884
 885#ifdef CONFIG_IPV6_SUBTREES
 886        /* Subtree creation failed, probably main tree node
 887           is orphan. If it is, shoot it.
 888         */
 889st_failure:
 890        if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 891                fib6_repair_tree(info->nl_net, fn);
 892        dst_free(&rt->dst);
 893        return err;
 894#endif
 895}
 896
 897/*
 898 *      Routing tree lookup
 899 *
 900 */
 901
 902struct lookup_args {
 903        int                     offset;         /* key offset on rt6_info       */
 904        const struct in6_addr   *addr;          /* search key                   */
 905};
 906
 907static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 908                                        struct lookup_args *args)
 909{
 910        struct fib6_node *fn;
 911        __be32 dir;
 912
 913        if (unlikely(args->offset == 0))
 914                return NULL;
 915
 916        /*
 917         *      Descend on a tree
 918         */
 919
 920        fn = root;
 921
 922        for (;;) {
 923                struct fib6_node *next;
 924
 925                dir = addr_bit_set(args->addr, fn->fn_bit);
 926
 927                next = dir ? fn->right : fn->left;
 928
 929                if (next) {
 930                        fn = next;
 931                        continue;
 932                }
 933                break;
 934        }
 935
 936        while (fn) {
 937                if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
 938                        struct rt6key *key;
 939
 940                        key = (struct rt6key *) ((u8 *) fn->leaf +
 941                                                 args->offset);
 942
 943                        if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 944#ifdef CONFIG_IPV6_SUBTREES
 945                                if (fn->subtree)
 946                                        fn = fib6_lookup_1(fn->subtree, args + 1);
 947#endif
 948                                if (!fn || fn->fn_flags & RTN_RTINFO)
 949                                        return fn;
 950                        }
 951                }
 952
 953                if (fn->fn_flags & RTN_ROOT)
 954                        break;
 955
 956                fn = fn->parent;
 957        }
 958
 959        return NULL;
 960}
 961
 962struct fib6_node * fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
 963                               const struct in6_addr *saddr)
 964{
 965        struct fib6_node *fn;
 966        struct lookup_args args[] = {
 967                {
 968                        .offset = offsetof(struct rt6_info, rt6i_dst),
 969                        .addr = daddr,
 970                },
 971#ifdef CONFIG_IPV6_SUBTREES
 972                {
 973                        .offset = offsetof(struct rt6_info, rt6i_src),
 974                        .addr = saddr,
 975                },
 976#endif
 977                {
 978                        .offset = 0,    /* sentinel */
 979                }
 980        };
 981
 982        fn = fib6_lookup_1(root, daddr ? args : args + 1);
 983        if (!fn || fn->fn_flags & RTN_TL_ROOT)
 984                fn = root;
 985
 986        return fn;
 987}
 988
 989/*
 990 *      Get node with specified destination prefix (and source prefix,
 991 *      if subtrees are used)
 992 */
 993
 994
 995static struct fib6_node * fib6_locate_1(struct fib6_node *root,
 996                                        const struct in6_addr *addr,
 997                                        int plen, int offset)
 998{
 999        struct fib6_node *fn;
1000
1001        for (fn = root; fn ; ) {
1002                struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1003
1004                /*
1005                 *      Prefix match
1006                 */
1007                if (plen < fn->fn_bit ||
1008                    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1009                        return NULL;
1010
1011                if (plen == fn->fn_bit)
1012                        return fn;
1013
1014                /*
1015                 *      We have more bits to go
1016                 */
1017                if (addr_bit_set(addr, fn->fn_bit))
1018                        fn = fn->right;
1019                else
1020                        fn = fn->left;
1021        }
1022        return NULL;
1023}
1024
1025struct fib6_node * fib6_locate(struct fib6_node *root,
1026                               const struct in6_addr *daddr, int dst_len,
1027                               const struct in6_addr *saddr, int src_len)
1028{
1029        struct fib6_node *fn;
1030
1031        fn = fib6_locate_1(root, daddr, dst_len,
1032                           offsetof(struct rt6_info, rt6i_dst));
1033
1034#ifdef CONFIG_IPV6_SUBTREES
1035        if (src_len) {
1036                WARN_ON(saddr == NULL);
1037                if (fn && fn->subtree)
1038                        fn = fib6_locate_1(fn->subtree, saddr, src_len,
1039                                           offsetof(struct rt6_info, rt6i_src));
1040        }
1041#endif
1042
1043        if (fn && fn->fn_flags & RTN_RTINFO)
1044                return fn;
1045
1046        return NULL;
1047}
1048
1049
1050/*
1051 *      Deletion
1052 *
1053 */
1054
1055static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1056{
1057        if (fn->fn_flags & RTN_ROOT)
1058                return net->ipv6.ip6_null_entry;
1059
1060        while (fn) {
1061                if (fn->left)
1062                        return fn->left->leaf;
1063                if (fn->right)
1064                        return fn->right->leaf;
1065
1066                fn = FIB6_SUBTREE(fn);
1067        }
1068        return NULL;
1069}
1070
1071/*
1072 *      Called to trim the tree of intermediate nodes when possible. "fn"
1073 *      is the node we want to try and remove.
1074 */
1075
1076static struct fib6_node *fib6_repair_tree(struct net *net,
1077                                           struct fib6_node *fn)
1078{
1079        int children;
1080        int nstate;
1081        struct fib6_node *child, *pn;
1082        struct fib6_walker_t *w;
1083        int iter = 0;
1084
1085        for (;;) {
1086                RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1087                iter++;
1088
1089                WARN_ON(fn->fn_flags & RTN_RTINFO);
1090                WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1091                WARN_ON(fn->leaf != NULL);
1092
1093                children = 0;
1094                child = NULL;
1095                if (fn->right) child = fn->right, children |= 1;
1096                if (fn->left) child = fn->left, children |= 2;
1097
1098                if (children == 3 || FIB6_SUBTREE(fn)
1099#ifdef CONFIG_IPV6_SUBTREES
1100                    /* Subtree root (i.e. fn) may have one child */
1101                    || (children && fn->fn_flags & RTN_ROOT)
1102#endif
1103                    ) {
1104                        fn->leaf = fib6_find_prefix(net, fn);
1105#if RT6_DEBUG >= 2
1106                        if (!fn->leaf) {
1107                                WARN_ON(!fn->leaf);
1108                                fn->leaf = net->ipv6.ip6_null_entry;
1109                        }
1110#endif
1111                        atomic_inc(&fn->leaf->rt6i_ref);
1112                        return fn->parent;
1113                }
1114
1115                pn = fn->parent;
1116#ifdef CONFIG_IPV6_SUBTREES
1117                if (FIB6_SUBTREE(pn) == fn) {
1118                        WARN_ON(!(fn->fn_flags & RTN_ROOT));
1119                        FIB6_SUBTREE(pn) = NULL;
1120                        nstate = FWS_L;
1121                } else {
1122                        WARN_ON(fn->fn_flags & RTN_ROOT);
1123#endif
1124                        if (pn->right == fn) pn->right = child;
1125                        else if (pn->left == fn) pn->left = child;
1126#if RT6_DEBUG >= 2
1127                        else
1128                                WARN_ON(1);
1129#endif
1130                        if (child)
1131                                child->parent = pn;
1132                        nstate = FWS_R;
1133#ifdef CONFIG_IPV6_SUBTREES
1134                }
1135#endif
1136
1137                read_lock(&fib6_walker_lock);
1138                FOR_WALKERS(w) {
1139                        if (!child) {
1140                                if (w->root == fn) {
1141                                        w->root = w->node = NULL;
1142                                        RT6_TRACE("W %p adjusted by delroot 1\n", w);
1143                                } else if (w->node == fn) {
1144                                        RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1145                                        w->node = pn;
1146                                        w->state = nstate;
1147                                }
1148                        } else {
1149                                if (w->root == fn) {
1150                                        w->root = child;
1151                                        RT6_TRACE("W %p adjusted by delroot 2\n", w);
1152                                }
1153                                if (w->node == fn) {
1154                                        w->node = child;
1155                                        if (children&2) {
1156                                                RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1157                                                w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1158                                        } else {
1159                                                RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1160                                                w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1161                                        }
1162                                }
1163                        }
1164                }
1165                read_unlock(&fib6_walker_lock);
1166
1167                node_free(fn);
1168                if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1169                        return pn;
1170
1171                rt6_release(pn->leaf);
1172                pn->leaf = NULL;
1173                fn = pn;
1174        }
1175}
1176
1177static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1178                           struct nl_info *info)
1179{
1180        struct fib6_walker_t *w;
1181        struct rt6_info *rt = *rtp;
1182        struct net *net = info->nl_net;
1183
1184        RT6_TRACE("fib6_del_route\n");
1185
1186        /* Unlink it */
1187        *rtp = rt->dst.rt6_next;
1188        rt->rt6i_node = NULL;
1189        net->ipv6.rt6_stats->fib_rt_entries--;
1190        net->ipv6.rt6_stats->fib_discarded_routes++;
1191
1192        /* Reset round-robin state, if necessary */
1193        if (fn->rr_ptr == rt)
1194                fn->rr_ptr = NULL;
1195
1196        /* Adjust walkers */
1197        read_lock(&fib6_walker_lock);
1198        FOR_WALKERS(w) {
1199                if (w->state == FWS_C && w->leaf == rt) {
1200                        RT6_TRACE("walker %p adjusted by delroute\n", w);
1201                        w->leaf = rt->dst.rt6_next;
1202                        if (!w->leaf)
1203                                w->state = FWS_U;
1204                }
1205        }
1206        read_unlock(&fib6_walker_lock);
1207
1208        rt->dst.rt6_next = NULL;
1209
1210        /* If it was last route, expunge its radix tree node */
1211        if (!fn->leaf) {
1212                fn->fn_flags &= ~RTN_RTINFO;
1213                net->ipv6.rt6_stats->fib_route_nodes--;
1214                fn = fib6_repair_tree(net, fn);
1215        }
1216
1217        if (atomic_read(&rt->rt6i_ref) != 1) {
1218                /* This route is used as dummy address holder in some split
1219                 * nodes. It is not leaked, but it still holds other resources,
1220                 * which must be released in time. So, scan ascendant nodes
1221                 * and replace dummy references to this route with references
1222                 * to still alive ones.
1223                 */
1224                while (fn) {
1225                        if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
1226                                fn->leaf = fib6_find_prefix(net, fn);
1227                                atomic_inc(&fn->leaf->rt6i_ref);
1228                                rt6_release(rt);
1229                        }
1230                        fn = fn->parent;
1231                }
1232                /* No more references are possible at this point. */
1233                BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1234        }
1235
1236        inet6_rt_notify(RTM_DELROUTE, rt, info);
1237        rt6_release(rt);
1238}
1239
1240int fib6_del(struct rt6_info *rt, struct nl_info *info)
1241{
1242        struct net *net = info->nl_net;
1243        struct fib6_node *fn = rt->rt6i_node;
1244        struct rt6_info **rtp;
1245
1246#if RT6_DEBUG >= 2
1247        if (rt->dst.obsolete>0) {
1248                WARN_ON(fn != NULL);
1249                return -ENOENT;
1250        }
1251#endif
1252        if (!fn || rt == net->ipv6.ip6_null_entry)
1253                return -ENOENT;
1254
1255        WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1256
1257        if (!(rt->rt6i_flags & RTF_CACHE)) {
1258                struct fib6_node *pn = fn;
1259#ifdef CONFIG_IPV6_SUBTREES
1260                /* clones of this route might be in another subtree */
1261                if (rt->rt6i_src.plen) {
1262                        while (!(pn->fn_flags & RTN_ROOT))
1263                                pn = pn->parent;
1264                        pn = pn->parent;
1265                }
1266#endif
1267                fib6_prune_clones(info->nl_net, pn, rt);
1268        }
1269
1270        /*
1271         *      Walk the leaf entries looking for ourself
1272         */
1273
1274        for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1275                if (*rtp == rt) {
1276                        fib6_del_route(fn, rtp, info);
1277                        return 0;
1278                }
1279        }
1280        return -ENOENT;
1281}
1282
1283/*
1284 *      Tree traversal function.
1285 *
1286 *      Certainly, it is not interrupt safe.
1287 *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1288 *      It means, that we can modify tree during walking
1289 *      and use this function for garbage collection, clone pruning,
1290 *      cleaning tree when a device goes down etc. etc.
1291 *
1292 *      It guarantees that every node will be traversed,
1293 *      and that it will be traversed only once.
1294 *
1295 *      Callback function w->func may return:
1296 *      0 -> continue walking.
1297 *      positive value -> walking is suspended (used by tree dumps,
1298 *      and probably by gc, if it will be split to several slices)
1299 *      negative value -> terminate walking.
1300 *
1301 *      The function itself returns:
1302 *      0   -> walk is complete.
1303 *      >0  -> walk is incomplete (i.e. suspended)
1304 *      <0  -> walk is terminated by an error.
1305 */
1306
1307static int fib6_walk_continue(struct fib6_walker_t *w)
1308{
1309        struct fib6_node *fn, *pn;
1310
1311        for (;;) {
1312                fn = w->node;
1313                if (!fn)
1314                        return 0;
1315
1316                if (w->prune && fn != w->root &&
1317                    fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1318                        w->state = FWS_C;
1319                        w->leaf = fn->leaf;
1320                }
1321                switch (w->state) {
1322#ifdef CONFIG_IPV6_SUBTREES
1323                case FWS_S:
1324                        if (FIB6_SUBTREE(fn)) {
1325                                w->node = FIB6_SUBTREE(fn);
1326                                continue;
1327                        }
1328                        w->state = FWS_L;
1329#endif
1330                case FWS_L:
1331                        if (fn->left) {
1332                                w->node = fn->left;
1333                                w->state = FWS_INIT;
1334                                continue;
1335                        }
1336                        w->state = FWS_R;
1337                case FWS_R:
1338                        if (fn->right) {
1339                                w->node = fn->right;
1340                                w->state = FWS_INIT;
1341                                continue;
1342                        }
1343                        w->state = FWS_C;
1344                        w->leaf = fn->leaf;
1345                case FWS_C:
1346                        if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1347                                int err;
1348
1349                                if (w->skip) {
1350                                        w->skip--;
1351                                        continue;
1352                                }
1353
1354                                err = w->func(w);
1355                                if (err)
1356                                        return err;
1357
1358                                w->count++;
1359                                continue;
1360                        }
1361                        w->state = FWS_U;
1362                case FWS_U:
1363                        if (fn == w->root)
1364                                return 0;
1365                        pn = fn->parent;
1366                        w->node = pn;
1367#ifdef CONFIG_IPV6_SUBTREES
1368                        if (FIB6_SUBTREE(pn) == fn) {
1369                                WARN_ON(!(fn->fn_flags & RTN_ROOT));
1370                                w->state = FWS_L;
1371                                continue;
1372                        }
1373#endif
1374                        if (pn->left == fn) {
1375                                w->state = FWS_R;
1376                                continue;
1377                        }
1378                        if (pn->right == fn) {
1379                                w->state = FWS_C;
1380                                w->leaf = w->node->leaf;
1381                                continue;
1382                        }
1383#if RT6_DEBUG >= 2
1384                        WARN_ON(1);
1385#endif
1386                }
1387        }
1388}
1389
1390static int fib6_walk(struct fib6_walker_t *w)
1391{
1392        int res;
1393
1394        w->state = FWS_INIT;
1395        w->node = w->root;
1396
1397        fib6_walker_link(w);
1398        res = fib6_walk_continue(w);
1399        if (res <= 0)
1400                fib6_walker_unlink(w);
1401        return res;
1402}
1403
1404static int fib6_clean_node(struct fib6_walker_t *w)
1405{
1406        int res;
1407        struct rt6_info *rt;
1408        struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1409        struct nl_info info = {
1410                .nl_net = c->net,
1411        };
1412
1413        for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1414                res = c->func(rt, c->arg);
1415                if (res < 0) {
1416                        w->leaf = rt;
1417                        res = fib6_del(rt, &info);
1418                        if (res) {
1419#if RT6_DEBUG >= 2
1420                                pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1421                                         __func__, rt, rt->rt6i_node, res);
1422#endif
1423                                continue;
1424                        }
1425                        return 0;
1426                }
1427                WARN_ON(res != 0);
1428        }
1429        w->leaf = rt;
1430        return 0;
1431}
1432
1433/*
1434 *      Convenient frontend to tree walker.
1435 *
1436 *      func is called on each route.
1437 *              It may return -1 -> delete this route.
1438 *                            0  -> continue walking
1439 *
1440 *      prune==1 -> only immediate children of node (certainly,
1441 *      ignoring pure split nodes) will be scanned.
1442 */
1443
1444static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1445                            int (*func)(struct rt6_info *, void *arg),
1446                            int prune, void *arg)
1447{
1448        struct fib6_cleaner_t c;
1449
1450        c.w.root = root;
1451        c.w.func = fib6_clean_node;
1452        c.w.prune = prune;
1453        c.w.count = 0;
1454        c.w.skip = 0;
1455        c.func = func;
1456        c.arg = arg;
1457        c.net = net;
1458
1459        fib6_walk(&c.w);
1460}
1461
1462void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg),
1463                    int prune, void *arg)
1464{
1465        struct fib6_table *table;
1466        struct hlist_node *node;
1467        struct hlist_head *head;
1468        unsigned int h;
1469
1470        rcu_read_lock();
1471        for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1472                head = &net->ipv6.fib_table_hash[h];
1473                hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1474                        read_lock_bh(&table->tb6_lock);
1475                        fib6_clean_tree(net, &table->tb6_root,
1476                                        func, prune, arg);
1477                        read_unlock_bh(&table->tb6_lock);
1478                }
1479        }
1480        rcu_read_unlock();
1481}
1482void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
1483                    int prune, void *arg)
1484{
1485        struct fib6_table *table;
1486        struct hlist_node *node;
1487        struct hlist_head *head;
1488        unsigned int h;
1489
1490        rcu_read_lock();
1491        for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1492                head = &net->ipv6.fib_table_hash[h];
1493                hlist_for_each_entry_rcu(table, node, head, tb6_hlist) {
1494                        write_lock_bh(&table->tb6_lock);
1495                        fib6_clean_tree(net, &table->tb6_root,
1496                                        func, prune, arg);
1497                        write_unlock_bh(&table->tb6_lock);
1498                }
1499        }
1500        rcu_read_unlock();
1501}
1502
1503static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1504{
1505        if (rt->rt6i_flags & RTF_CACHE) {
1506                RT6_TRACE("pruning clone %p\n", rt);
1507                return -1;
1508        }
1509
1510        return 0;
1511}
1512
1513static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
1514                              struct rt6_info *rt)
1515{
1516        fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
1517}
1518
1519/*
1520 *      Garbage collection
1521 */
1522
1523static struct fib6_gc_args
1524{
1525        int                     timeout;
1526        int                     more;
1527} gc_args;
1528
1529static int fib6_age(struct rt6_info *rt, void *arg)
1530{
1531        unsigned long now = jiffies;
1532
1533        /*
1534         *      check addrconf expiration here.
1535         *      Routes are expired even if they are in use.
1536         *
1537         *      Also age clones. Note, that clones are aged out
1538         *      only if they are not in use now.
1539         */
1540
1541        if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1542                if (time_after(now, rt->dst.expires)) {
1543                        RT6_TRACE("expiring %p\n", rt);
1544                        return -1;
1545                }
1546                gc_args.more++;
1547        } else if (rt->rt6i_flags & RTF_CACHE) {
1548                if (atomic_read(&rt->dst.__refcnt) == 0 &&
1549                    time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1550                        RT6_TRACE("aging clone %p\n", rt);
1551                        return -1;
1552                } else if (rt->rt6i_flags & RTF_GATEWAY) {
1553                        struct neighbour *neigh;
1554                        __u8 neigh_flags = 0;
1555
1556                        neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1557                        if (neigh) {
1558                                neigh_flags = neigh->flags;
1559                                neigh_release(neigh);
1560                        }
1561                        if (!(neigh_flags & NTF_ROUTER)) {
1562                                RT6_TRACE("purging route %p via non-router but gateway\n",
1563                                          rt);
1564                                return -1;
1565                        }
1566                }
1567                gc_args.more++;
1568        }
1569
1570        return 0;
1571}
1572
1573static DEFINE_SPINLOCK(fib6_gc_lock);
1574
1575void fib6_run_gc(unsigned long expires, struct net *net)
1576{
1577        if (expires != ~0UL) {
1578                spin_lock_bh(&fib6_gc_lock);
1579                gc_args.timeout = expires ? (int)expires :
1580                        net->ipv6.sysctl.ip6_rt_gc_interval;
1581        } else {
1582                if (!spin_trylock_bh(&fib6_gc_lock)) {
1583                        mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1584                        return;
1585                }
1586                gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
1587        }
1588
1589        gc_args.more = icmp6_dst_gc();
1590
1591        fib6_clean_all(net, fib6_age, 0, NULL);
1592
1593        if (gc_args.more)
1594                mod_timer(&net->ipv6.ip6_fib_timer,
1595                          round_jiffies(jiffies
1596                                        + net->ipv6.sysctl.ip6_rt_gc_interval));
1597        else
1598                del_timer(&net->ipv6.ip6_fib_timer);
1599        spin_unlock_bh(&fib6_gc_lock);
1600}
1601
1602static void fib6_gc_timer_cb(unsigned long arg)
1603{
1604        fib6_run_gc(0, (struct net *)arg);
1605}
1606
1607static int __net_init fib6_net_init(struct net *net)
1608{
1609        size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1610
1611        setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1612
1613        net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1614        if (!net->ipv6.rt6_stats)
1615                goto out_timer;
1616
1617        /* Avoid false sharing : Use at least a full cache line */
1618        size = max_t(size_t, size, L1_CACHE_BYTES);
1619
1620        net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1621        if (!net->ipv6.fib_table_hash)
1622                goto out_rt6_stats;
1623
1624        net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1625                                          GFP_KERNEL);
1626        if (!net->ipv6.fib6_main_tbl)
1627                goto out_fib_table_hash;
1628
1629        net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1630        net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1631        net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1632                RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1633        inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1634
1635#ifdef CONFIG_IPV6_MULTIPLE_TABLES
1636        net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1637                                           GFP_KERNEL);
1638        if (!net->ipv6.fib6_local_tbl)
1639                goto out_fib6_main_tbl;
1640        net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1641        net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1642        net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1643                RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1644        inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1645#endif
1646        fib6_tables_init(net);
1647
1648        return 0;
1649
1650#ifdef CONFIG_IPV6_MULTIPLE_TABLES
1651out_fib6_main_tbl:
1652        kfree(net->ipv6.fib6_main_tbl);
1653#endif
1654out_fib_table_hash:
1655        kfree(net->ipv6.fib_table_hash);
1656out_rt6_stats:
1657        kfree(net->ipv6.rt6_stats);
1658out_timer:
1659        return -ENOMEM;
1660 }
1661
1662static void fib6_net_exit(struct net *net)
1663{
1664        rt6_ifdown(net, NULL);
1665        del_timer_sync(&net->ipv6.ip6_fib_timer);
1666
1667#ifdef CONFIG_IPV6_MULTIPLE_TABLES
1668        inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1669        kfree(net->ipv6.fib6_local_tbl);
1670#endif
1671        inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1672        kfree(net->ipv6.fib6_main_tbl);
1673        kfree(net->ipv6.fib_table_hash);
1674        kfree(net->ipv6.rt6_stats);
1675}
1676
1677static struct pernet_operations fib6_net_ops = {
1678        .init = fib6_net_init,
1679        .exit = fib6_net_exit,
1680};
1681
1682int __init fib6_init(void)
1683{
1684        int ret = -ENOMEM;
1685
1686        fib6_node_kmem = kmem_cache_create("fib6_nodes",
1687                                           sizeof(struct fib6_node),
1688                                           0, SLAB_HWCACHE_ALIGN,
1689                                           NULL);
1690        if (!fib6_node_kmem)
1691                goto out;
1692
1693        ret = register_pernet_subsys(&fib6_net_ops);
1694        if (ret)
1695                goto out_kmem_cache_create;
1696
1697        ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1698                              NULL);
1699        if (ret)
1700                goto out_unregister_subsys;
1701out:
1702        return ret;
1703
1704out_unregister_subsys:
1705        unregister_pernet_subsys(&fib6_net_ops);
1706out_kmem_cache_create:
1707        kmem_cache_destroy(fib6_node_kmem);
1708        goto out;
1709}
1710
1711void fib6_gc_cleanup(void)
1712{
1713        unregister_pernet_subsys(&fib6_net_ops);
1714        kmem_cache_destroy(fib6_node_kmem);
1715}
1716
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