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        unsigned int h;
 228
 229        if (id == 0)
 230                id = RT6_TABLE_MAIN;
 231        h = id & (FIB6_TABLE_HASHSZ - 1);
 232        rcu_read_lock();
 233        head = &net->ipv6.fib_table_hash[h];
 234        hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 235                if (tb->tb6_id == id) {
 236                        rcu_read_unlock();
 237                        return tb;
 238                }
 239        }
 240        rcu_read_unlock();
 241
 242        return NULL;
 243}
 244
 245static void __net_init fib6_tables_init(struct net *net)
 246{
 247        fib6_link_table(net, net->ipv6.fib6_main_tbl);
 248        fib6_link_table(net, net->ipv6.fib6_local_tbl);
 249}
 250#else
 251
 252struct fib6_table *fib6_new_table(struct net *net, u32 id)
 253{
 254        return fib6_get_table(net, id);
 255}
 256
 257struct fib6_table *fib6_get_table(struct net *net, u32 id)
 258{
 259          return net->ipv6.fib6_main_tbl;
 260}
 261
 262struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 263                                   int flags, pol_lookup_t lookup)
 264{
 265        return (struct dst_entry *) lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
 266}
 267
 268static void __net_init fib6_tables_init(struct net *net)
 269{
 270        fib6_link_table(net, net->ipv6.fib6_main_tbl);
 271}
 272
 273#endif
 274
 275static int fib6_dump_node(struct fib6_walker_t *w)
 276{
 277        int res;
 278        struct rt6_info *rt;
 279
 280        for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
 281                res = rt6_dump_route(rt, w->args);
 282                if (res < 0) {
 283                        /* Frame is full, suspend walking */
 284                        w->leaf = rt;
 285                        return 1;
 286                }
 287                WARN_ON(res == 0);
 288        }
 289        w->leaf = NULL;
 290        return 0;
 291}
 292
 293static void fib6_dump_end(struct netlink_callback *cb)
 294{
 295        struct fib6_walker_t *w = (void*)cb->args[2];
 296
 297        if (w) {
 298                if (cb->args[4]) {
 299                        cb->args[4] = 0;
 300                        fib6_walker_unlink(w);
 301                }
 302                cb->args[2] = 0;
 303                kfree(w);
 304        }
 305        cb->done = (void*)cb->args[3];
 306        cb->args[1] = 3;
 307}
 308
 309static int fib6_dump_done(struct netlink_callback *cb)
 310{
 311        fib6_dump_end(cb);
 312        return cb->done ? cb->done(cb) : 0;
 313}
 314
 315static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
 316                           struct netlink_callback *cb)
 317{
 318        struct fib6_walker_t *w;
 319        int res;
 320
 321        w = (void *)cb->args[2];
 322        w->root = &table->tb6_root;
 323
 324        if (cb->args[4] == 0) {
 325                w->count = 0;
 326                w->skip = 0;
 327
 328                read_lock_bh(&table->tb6_lock);
 329                res = fib6_walk(w);
 330                read_unlock_bh(&table->tb6_lock);
 331                if (res > 0) {
 332                        cb->args[4] = 1;
 333                        cb->args[5] = w->root->fn_sernum;
 334                }
 335        } else {
 336                if (cb->args[5] != w->root->fn_sernum) {
 337                        /* Begin at the root if the tree changed */
 338                        cb->args[5] = w->root->fn_sernum;
 339                        w->state = FWS_INIT;
 340                        w->node = w->root;
 341                        w->skip = w->count;
 342                } else
 343                        w->skip = 0;
 344
 345                read_lock_bh(&table->tb6_lock);
 346                res = fib6_walk_continue(w);
 347                read_unlock_bh(&table->tb6_lock);
 348                if (res <= 0) {
 349                        fib6_walker_unlink(w);
 350                        cb->args[4] = 0;
 351                }
 352        }
 353
 354        return res;
 355}
 356
 357static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 358{
 359        struct net *net = sock_net(skb->sk);
 360        unsigned int h, s_h;
 361        unsigned int e = 0, s_e;
 362        struct rt6_rtnl_dump_arg arg;
 363        struct fib6_walker_t *w;
 364        struct fib6_table *tb;
 365        struct hlist_head *head;
 366        int res = 0;
 367
 368        s_h = cb->args[0];
 369        s_e = cb->args[1];
 370
 371        w = (void *)cb->args[2];
 372        if (!w) {
 373                /* New dump:
 374                 *
 375                 * 1. hook callback destructor.
 376                 */
 377                cb->args[3] = (long)cb->done;
 378                cb->done = fib6_dump_done;
 379
 380                /*
 381                 * 2. allocate and initialize walker.
 382                 */
 383                w = kzalloc(sizeof(*w), GFP_ATOMIC);
 384                if (!w)
 385                        return -ENOMEM;
 386                w->func = fib6_dump_node;
 387                cb->args[2] = (long)w;
 388        }
 389
 390        arg.skb = skb;
 391        arg.cb = cb;
 392        arg.net = net;
 393        w->args = &arg;
 394
 395        rcu_read_lock();
 396        for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 397                e = 0;
 398                head = &net->ipv6.fib_table_hash[h];
 399                hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
 400                        if (e < s_e)
 401                                goto next;
 402                        res = fib6_dump_table(tb, skb, cb);
 403                        if (res != 0)
 404                                goto out;
 405next:
 406                        e++;
 407                }
 408        }
 409out:
 410        rcu_read_unlock();
 411        cb->args[1] = e;
 412        cb->args[0] = h;
 413
 414        res = res < 0 ? res : skb->len;
 415        if (res <= 0)
 416                fib6_dump_end(cb);
 417        return res;
 418}
 419
 420/*
 421 *      Routing Table
 422 *
 423 *      return the appropriate node for a routing tree "add" operation
 424 *      by either creating and inserting or by returning an existing
 425 *      node.
 426 */
 427
 428static struct fib6_node *fib6_add_1(struct fib6_node *root,
 429                                     struct in6_addr *addr, int plen,
 430                                     int offset, int allow_create,
 431                                     int replace_required)
 432{
 433        struct fib6_node *fn, *in, *ln;
 434        struct fib6_node *pn = NULL;
 435        struct rt6key *key;
 436        int     bit;
 437        __be32  dir = 0;
 438        __u32   sernum = fib6_new_sernum();
 439
 440        RT6_TRACE("fib6_add_1\n");
 441
 442        /* insert node in tree */
 443
 444        fn = root;
 445
 446        do {
 447                key = (struct rt6key *)((u8 *)fn->leaf + offset);
 448
 449                /*
 450                 *      Prefix match
 451                 */
 452                if (plen < fn->fn_bit ||
 453                    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
 454                        if (!allow_create) {
 455                                if (replace_required) {
 456                                        pr_warn("Can't replace route, no match found\n");
 457                                        return ERR_PTR(-ENOENT);
 458                                }
 459                                pr_warn("NLM_F_CREATE should be set when creating new route\n");
 460                        }
 461                        goto insert_above;
 462                }
 463
 464                /*
 465                 *      Exact match ?
 466                 */
 467
 468                if (plen == fn->fn_bit) {
 469                        /* clean up an intermediate node */
 470                        if (!(fn->fn_flags & RTN_RTINFO)) {
 471                                rt6_release(fn->leaf);
 472                                fn->leaf = NULL;
 473                        }
 474
 475                        fn->fn_sernum = sernum;
 476
 477                        return fn;
 478                }
 479
 480                /*
 481                 *      We have more bits to go
 482                 */
 483
 484                /* Try to walk down on tree. */
 485                fn->fn_sernum = sernum;
 486                dir = addr_bit_set(addr, fn->fn_bit);
 487                pn = fn;
 488                fn = dir ? fn->right: fn->left;
 489        } while (fn);
 490
 491        if (!allow_create) {
 492                /* We should not create new node because
 493                 * NLM_F_REPLACE was specified without NLM_F_CREATE
 494                 * I assume it is safe to require NLM_F_CREATE when
 495                 * REPLACE flag is used! Later we may want to remove the
 496                 * check for replace_required, because according
 497                 * to netlink specification, NLM_F_CREATE
 498                 * MUST be specified if new route is created.
 499                 * That would keep IPv6 consistent with IPv4
 500                 */
 501                if (replace_required) {
 502                        pr_warn("Can't replace route, no match found\n");
 503                        return ERR_PTR(-ENOENT);
 504                }
 505                pr_warn("NLM_F_CREATE should be set when creating new route\n");
 506        }
 507        /*
 508         *      We walked to the bottom of tree.
 509         *      Create new leaf node without children.
 510         */
 511
 512        ln = node_alloc();
 513
 514        if (!ln)
 515                return ERR_PTR(-ENOMEM);
 516        ln->fn_bit = plen;
 517
 518        ln->parent = pn;
 519        ln->fn_sernum = sernum;
 520
 521        if (dir)
 522                pn->right = ln;
 523        else
 524                pn->left  = ln;
 525
 526        return ln;
 527
 528
 529insert_above:
 530        /*
 531         * split since we don't have a common prefix anymore or
 532         * we have a less significant route.
 533         * we've to insert an intermediate node on the list
 534         * this new node will point to the one we need to create
 535         * and the current
 536         */
 537
 538        pn = fn->parent;
 539
 540        /* find 1st bit in difference between the 2 addrs.
 541
 542           See comment in __ipv6_addr_diff: bit may be an invalid value,
 543           but if it is >= plen, the value is ignored in any case.
 544         */
 545
 546        bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
 547
 548        /*
 549         *              (intermediate)[in]
 550         *                /        \
 551         *      (new leaf node)[ln] (old node)[fn]
 552         */
 553        if (plen > bit) {
 554                in = node_alloc();
 555                ln = node_alloc();
 556
 557                if (!in || !ln) {
 558                        if (in)
 559                                node_free(in);
 560                        if (ln)
 561                                node_free(ln);
 562                        return ERR_PTR(-ENOMEM);
 563                }
 564
 565                /*
 566                 * new intermediate node.
 567                 * RTN_RTINFO will
 568                 * be off since that an address that chooses one of
 569                 * the branches would not match less specific routes
 570                 * in the other branch
 571                 */
 572
 573                in->fn_bit = bit;
 574
 575                in->parent = pn;
 576                in->leaf = fn->leaf;
 577                atomic_inc(&in->leaf->rt6i_ref);
 578
 579                in->fn_sernum = sernum;
 580
 581                /* update parent pointer */
 582                if (dir)
 583                        pn->right = in;
 584                else
 585                        pn->left  = in;
 586
 587                ln->fn_bit = plen;
 588
 589                ln->parent = in;
 590                fn->parent = in;
 591
 592                ln->fn_sernum = sernum;
 593
 594                if (addr_bit_set(addr, bit)) {
 595                        in->right = ln;
 596                        in->left  = fn;
 597                } else {
 598                        in->left  = ln;
 599                        in->right = fn;
 600                }
 601        } else { /* plen <= bit */
 602
 603                /*
 604                 *              (new leaf node)[ln]
 605                 *                /        \
 606                 *           (old node)[fn] NULL
 607                 */
 608
 609                ln = node_alloc();
 610
 611                if (!ln)
 612                        return ERR_PTR(-ENOMEM);
 613
 614                ln->fn_bit = plen;
 615
 616                ln->parent = pn;
 617
 618                ln->fn_sernum = sernum;
 619
 620                if (dir)
 621                        pn->right = ln;
 622                else
 623                        pn->left  = ln;
 624
 625                if (addr_bit_set(&key->addr, plen))
 626                        ln->right = fn;
 627                else
 628                        ln->left  = fn;
 629
 630                fn->parent = ln;
 631        }
 632        return ln;
 633}
 634
 635static inline bool rt6_qualify_for_ecmp(struct rt6_info *rt)
 636{
 637        return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
 638               RTF_GATEWAY;
 639}
 640
 641/*
 642 *      Insert routing information in a node.
 643 */
 644
 645static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 646                            struct nl_info *info)
 647{
 648        struct rt6_info *iter = NULL;
 649        struct rt6_info **ins;
 650        int replace = (info->nlh &&
 651                       (info->nlh->nlmsg_flags & NLM_F_REPLACE));
 652        int add = (!info->nlh ||
 653                   (info->nlh->nlmsg_flags & NLM_F_CREATE));
 654        int found = 0;
 655        bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
 656
 657        ins = &fn->leaf;
 658
 659        for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
 660                /*
 661                 *      Search for duplicates
 662                 */
 663
 664                if (iter->rt6i_metric == rt->rt6i_metric) {
 665                        /*
 666                         *      Same priority level
 667                         */
 668                        if (info->nlh &&
 669                            (info->nlh->nlmsg_flags & NLM_F_EXCL))
 670                                return -EEXIST;
 671                        if (replace) {
 672                                found++;
 673                                break;
 674                        }
 675
 676                        if (iter->dst.dev == rt->dst.dev &&
 677                            iter->rt6i_idev == rt->rt6i_idev &&
 678                            ipv6_addr_equal(&iter->rt6i_gateway,
 679                                            &rt->rt6i_gateway)) {
 680                                if (rt->rt6i_nsiblings)
 681                                        rt->rt6i_nsiblings = 0;
 682                                if (!(iter->rt6i_flags & RTF_EXPIRES))
 683                                        return -EEXIST;
 684                                if (!(rt->rt6i_flags & RTF_EXPIRES))
 685                                        rt6_clean_expires(iter);
 686                                else
 687                                        rt6_set_expires(iter, rt->dst.expires);
 688                                return -EEXIST;
 689                        }
 690                        /* If we have the same destination and the same metric,
 691                         * but not the same gateway, then the route we try to
 692                         * add is sibling to this route, increment our counter
 693                         * of siblings, and later we will add our route to the
 694                         * list.
 695                         * Only static routes (which don't have flag
 696                         * RTF_EXPIRES) are used for ECMPv6.
 697                         *
 698                         * To avoid long list, we only had siblings if the
 699                         * route have a gateway.
 700                         */
 701                        if (rt_can_ecmp &&
 702                            rt6_qualify_for_ecmp(iter))
 703                                rt->rt6i_nsiblings++;
 704                }
 705
 706                if (iter->rt6i_metric > rt->rt6i_metric)
 707                        break;
 708
 709                ins = &iter->dst.rt6_next;
 710        }
 711
 712        /* Reset round-robin state, if necessary */
 713        if (ins == &fn->leaf)
 714                fn->rr_ptr = NULL;
 715
 716        /* Link this route to others same route. */
 717        if (rt->rt6i_nsiblings) {
 718                unsigned int rt6i_nsiblings;
 719                struct rt6_info *sibling, *temp_sibling;
 720
 721                /* Find the first route that have the same metric */
 722                sibling = fn->leaf;
 723                while (sibling) {
 724                        if (sibling->rt6i_metric == rt->rt6i_metric &&
 725                            rt6_qualify_for_ecmp(sibling)) {
 726                                list_add_tail(&rt->rt6i_siblings,
 727                                              &sibling->rt6i_siblings);
 728                                break;
 729                        }
 730                        sibling = sibling->dst.rt6_next;
 731                }
 732                /* For each sibling in the list, increment the counter of
 733                 * siblings. BUG() if counters does not match, list of siblings
 734                 * is broken!
 735                 */
 736                rt6i_nsiblings = 0;
 737                list_for_each_entry_safe(sibling, temp_sibling,
 738                                         &rt->rt6i_siblings, rt6i_siblings) {
 739                        sibling->rt6i_nsiblings++;
 740                        BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
 741                        rt6i_nsiblings++;
 742                }
 743                BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
 744        }
 745
 746        /*
 747         *      insert node
 748         */
 749        if (!replace) {
 750                if (!add)
 751                        pr_warn("NLM_F_CREATE should be set when creating new route\n");
 752
 753add:
 754                rt->dst.rt6_next = iter;
 755                *ins = rt;
 756                rt->rt6i_node = fn;
 757                atomic_inc(&rt->rt6i_ref);
 758                inet6_rt_notify(RTM_NEWROUTE, rt, info);
 759                info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 760
 761                if (!(fn->fn_flags & RTN_RTINFO)) {
 762                        info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 763                        fn->fn_flags |= RTN_RTINFO;
 764                }
 765
 766        } else {
 767                if (!found) {
 768                        if (add)
 769                                goto add;
 770                        pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
 771                        return -ENOENT;
 772                }
 773                *ins = rt;
 774                rt->rt6i_node = fn;
 775                rt->dst.rt6_next = iter->dst.rt6_next;
 776                atomic_inc(&rt->rt6i_ref);
 777                inet6_rt_notify(RTM_NEWROUTE, rt, info);
 778                rt6_release(iter);
 779                if (!(fn->fn_flags & RTN_RTINFO)) {
 780                        info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 781                        fn->fn_flags |= RTN_RTINFO;
 782                }
 783        }
 784
 785        return 0;
 786}
 787
 788static __inline__ void fib6_start_gc(struct net *net, struct rt6_info *rt)
 789{
 790        if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
 791            (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
 792                mod_timer(&net->ipv6.ip6_fib_timer,
 793                          jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 794}
 795
 796void fib6_force_start_gc(struct net *net)
 797{
 798        if (!timer_pending(&net->ipv6.ip6_fib_timer))
 799                mod_timer(&net->ipv6.ip6_fib_timer,
 800                          jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
 801}
 802
 803/*
 804 *      Add routing information to the routing tree.
 805 *      <destination addr>/<source addr>
 806 *      with source addr info in sub-trees
 807 */
 808
 809int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
 810{
 811        struct fib6_node *fn, *pn = NULL;
 812        int err = -ENOMEM;
 813        int allow_create = 1;
 814        int replace_required = 0;
 815
 816        if (info->nlh) {
 817                if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
 818                        allow_create = 0;
 819                if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
 820                        replace_required = 1;
 821        }
 822        if (!allow_create && !replace_required)
 823                pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
 824
 825        fn = fib6_add_1(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
 826                        offsetof(struct rt6_info, rt6i_dst), allow_create,
 827                        replace_required);
 828        if (IS_ERR(fn)) {
 829                err = PTR_ERR(fn);
 830                fn = NULL;
 831                goto out;
 832        }
 833
 834        pn = fn;
 835
 836#ifdef CONFIG_IPV6_SUBTREES
 837        if (rt->rt6i_src.plen) {
 838                struct fib6_node *sn;
 839
 840                if (!fn->subtree) {
 841                        struct fib6_node *sfn;
 842
 843                        /*
 844                         * Create subtree.
 845                         *
 846                         *              fn[main tree]
 847                         *              |
 848                         *              sfn[subtree root]
 849                         *                 \
 850                         *                  sn[new leaf node]
 851                         */
 852
 853                        /* Create subtree root node */
 854                        sfn = node_alloc();
 855                        if (!sfn)
 856                                goto st_failure;
 857
 858                        sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 859                        atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 860                        sfn->fn_flags = RTN_ROOT;
 861                        sfn->fn_sernum = fib6_new_sernum();
 862
 863                        /* Now add the first leaf node to new subtree */
 864
 865                        sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 866                                        rt->rt6i_src.plen,
 867                                        offsetof(struct rt6_info, rt6i_src),
 868                                        allow_create, replace_required);
 869
 870                        if (IS_ERR(sn)) {
 871                                /* If it is failed, discard just allocated
 872                                   root, and then (in st_failure) stale node
 873                                   in main tree.
 874                                 */
 875                                node_free(sfn);
 876                                err = PTR_ERR(sn);
 877                                goto st_failure;
 878                        }
 879
 880                        /* Now link new subtree to main tree */
 881                        sfn->parent = fn;
 882                        fn->subtree = sfn;
 883                } else {
 884                        sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 885                                        rt->rt6i_src.plen,
 886                                        offsetof(struct rt6_info, rt6i_src),
 887                                        allow_create, replace_required);
 888
 889                        if (IS_ERR(sn)) {
 890                                err = PTR_ERR(sn);
 891                                goto st_failure;
 892                        }
 893                }
 894
 895                if (!fn->leaf) {
 896                        fn->leaf = rt;
 897                        atomic_inc(&rt->rt6i_ref);
 898                }
 899                fn = sn;
 900        }
 901#endif
 902
 903        err = fib6_add_rt2node(fn, rt, info);
 904        if (!err) {
 905                fib6_start_gc(info->nl_net, rt);
 906                if (!(rt->rt6i_flags & RTF_CACHE))
 907                        fib6_prune_clones(info->nl_net, pn, rt);
 908        }
 909
 910out:
 911        if (err) {
 912#ifdef CONFIG_IPV6_SUBTREES
 913                /*
 914                 * If fib6_add_1 has cleared the old leaf pointer in the
 915                 * super-tree leaf node we have to find a new one for it.
 916                 */
 917                if (pn != fn && pn->leaf == rt) {
 918                        pn->leaf = NULL;
 919                        atomic_dec(&rt->rt6i_ref);
 920                }
 921                if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
 922                        pn->leaf = fib6_find_prefix(info->nl_net, pn);
 923#if RT6_DEBUG >= 2
 924                        if (!pn->leaf) {
 925                                WARN_ON(pn->leaf == NULL);
 926                                pn->leaf = info->nl_net->ipv6.ip6_null_entry;
 927                        }
 928#endif
 929                        atomic_inc(&pn->leaf->rt6i_ref);
 930                }
 931#endif
 932                dst_free(&rt->dst);
 933        }
 934        return err;
 935
 936#ifdef CONFIG_IPV6_SUBTREES
 937        /* Subtree creation failed, probably main tree node
 938           is orphan. If it is, shoot it.
 939         */
 940st_failure:
 941        if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
 942                fib6_repair_tree(info->nl_net, fn);
 943        dst_free(&rt->dst);
 944        return err;
 945#endif
 946}
 947
 948/*
 949 *      Routing tree lookup
 950 *
 951 */
 952
 953struct lookup_args {
 954        int                     offset;         /* key offset on rt6_info       */
 955        const struct in6_addr   *addr;          /* search key                   */
 956};
 957
 958static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 959                                        struct lookup_args *args)
 960{
 961        struct fib6_node *fn;
 962        __be32 dir;
 963
 964        if (unlikely(args->offset == 0))
 965                return NULL;
 966
 967        /*
 968         *      Descend on a tree
 969         */
 970
 971        fn = root;
 972
 973        for (;;) {
 974                struct fib6_node *next;
 975
 976                dir = addr_bit_set(args->addr, fn->fn_bit);
 977
 978                next = dir ? fn->right : fn->left;
 979
 980                if (next) {
 981                        fn = next;
 982                        continue;
 983                }
 984                break;
 985        }
 986
 987        while (fn) {
 988                if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
 989                        struct rt6key *key;
 990
 991                        key = (struct rt6key *) ((u8 *) fn->leaf +
 992                                                 args->offset);
 993
 994                        if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 995#ifdef CONFIG_IPV6_SUBTREES
 996                                if (fn->subtree) {
 997                                        struct fib6_node *sfn;
 998                                        sfn = fib6_lookup_1(fn->subtree,
 999                                                            args + 1);
1000                                        if (!sfn)
1001                                                goto backtrack;
1002                                        fn = sfn;
1003                                }
1004#endif
1005                                if (fn->fn_flags & RTN_RTINFO)
1006                                        return fn;
1007                        }
1008                }
1009#ifdef CONFIG_IPV6_SUBTREES
1010backtrack:
1011#endif
1012                if (fn->fn_flags & RTN_ROOT)
1013                        break;
1014
1015                fn = fn->parent;
1016        }
1017
1018        return NULL;
1019}
1020
1021struct fib6_node * fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
1022                               const struct in6_addr *saddr)
1023{
1024        struct fib6_node *fn;
1025        struct lookup_args args[] = {
1026                {
1027                        .offset = offsetof(struct rt6_info, rt6i_dst),
1028                        .addr = daddr,
1029                },
1030#ifdef CONFIG_IPV6_SUBTREES
1031                {
1032                        .offset = offsetof(struct rt6_info, rt6i_src),
1033                        .addr = saddr,
1034                },
1035#endif
1036                {
1037                        .offset = 0,    /* sentinel */
1038                }
1039        };
1040
1041        fn = fib6_lookup_1(root, daddr ? args : args + 1);
1042        if (!fn || fn->fn_flags & RTN_TL_ROOT)
1043                fn = root;
1044
1045        return fn;
1046}
1047
1048/*
1049 *      Get node with specified destination prefix (and source prefix,
1050 *      if subtrees are used)
1051 */
1052
1053
1054static struct fib6_node * fib6_locate_1(struct fib6_node *root,
1055                                        const struct in6_addr *addr,
1056                                        int plen, int offset)
1057{
1058        struct fib6_node *fn;
1059
1060        for (fn = root; fn ; ) {
1061                struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1062
1063                /*
1064                 *      Prefix match
1065                 */
1066                if (plen < fn->fn_bit ||
1067                    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1068                        return NULL;
1069
1070                if (plen == fn->fn_bit)
1071                        return fn;
1072
1073                /*
1074                 *      We have more bits to go
1075                 */
1076                if (addr_bit_set(addr, fn->fn_bit))
1077                        fn = fn->right;
1078                else
1079                        fn = fn->left;
1080        }
1081        return NULL;
1082}
1083
1084struct fib6_node * fib6_locate(struct fib6_node *root,
1085                               const struct in6_addr *daddr, int dst_len,
1086                               const struct in6_addr *saddr, int src_len)
1087{
1088        struct fib6_node *fn;
1089
1090        fn = fib6_locate_1(root, daddr, dst_len,
1091                           offsetof(struct rt6_info, rt6i_dst));
1092
1093#ifdef CONFIG_IPV6_SUBTREES
1094        if (src_len) {
1095                WARN_ON(saddr == NULL);
1096                if (fn && fn->subtree)
1097                        fn = fib6_locate_1(fn->subtree, saddr, src_len,
1098                                           offsetof(struct rt6_info, rt6i_src));
1099        }
1100#endif
1101
1102        if (fn && fn->fn_flags & RTN_RTINFO)
1103                return fn;
1104
1105        return NULL;
1106}
1107
1108
1109/*
1110 *      Deletion
1111 *
1112 */
1113
1114static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1115{
1116        if (fn->fn_flags & RTN_ROOT)
1117                return net->ipv6.ip6_null_entry;
1118
1119        while (fn) {
1120                if (fn->left)
1121                        return fn->left->leaf;
1122                if (fn->right)
1123                        return fn->right->leaf;
1124
1125                fn = FIB6_SUBTREE(fn);
1126        }
1127        return NULL;
1128}
1129
1130/*
1131 *      Called to trim the tree of intermediate nodes when possible. "fn"
1132 *      is the node we want to try and remove.
1133 */
1134
1135static struct fib6_node *fib6_repair_tree(struct net *net,
1136                                           struct fib6_node *fn)
1137{
1138        int children;
1139        int nstate;
1140        struct fib6_node *child, *pn;
1141        struct fib6_walker_t *w;
1142        int iter = 0;
1143
1144        for (;;) {
1145                RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1146                iter++;
1147
1148                WARN_ON(fn->fn_flags & RTN_RTINFO);
1149                WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1150                WARN_ON(fn->leaf != NULL);
1151
1152                children = 0;
1153                child = NULL;
1154                if (fn->right) child = fn->right, children |= 1;
1155                if (fn->left) child = fn->left, children |= 2;
1156
1157                if (children == 3 || FIB6_SUBTREE(fn)
1158#ifdef CONFIG_IPV6_SUBTREES
1159                    /* Subtree root (i.e. fn) may have one child */
1160                    || (children && fn->fn_flags & RTN_ROOT)
1161#endif
1162                    ) {
1163                        fn->leaf = fib6_find_prefix(net, fn);
1164#if RT6_DEBUG >= 2
1165                        if (!fn->leaf) {
1166                                WARN_ON(!fn->leaf);
1167                                fn->leaf = net->ipv6.ip6_null_entry;
1168                        }
1169#endif
1170                        atomic_inc(&fn->leaf->rt6i_ref);
1171                        return fn->parent;
1172                }
1173
1174                pn = fn->parent;
1175#ifdef CONFIG_IPV6_SUBTREES
1176                if (FIB6_SUBTREE(pn) == fn) {
1177                        WARN_ON(!(fn->fn_flags & RTN_ROOT));
1178                        FIB6_SUBTREE(pn) = NULL;
1179                        nstate = FWS_L;
1180                } else {
1181                        WARN_ON(fn->fn_flags & RTN_ROOT);
1182#endif
1183                        if (pn->right == fn) pn->right = child;
1184                        else if (pn->left == fn) pn->left = child;
1185#if RT6_DEBUG >= 2
1186                        else
1187                                WARN_ON(1);
1188#endif
1189                        if (child)
1190                                child->parent = pn;
1191                        nstate = FWS_R;
1192#ifdef CONFIG_IPV6_SUBTREES
1193                }
1194#endif
1195
1196                read_lock(&fib6_walker_lock);
1197                FOR_WALKERS(w) {
1198                        if (!child) {
1199                                if (w->root == fn) {
1200                                        w->root = w->node = NULL;
1201                                        RT6_TRACE("W %p adjusted by delroot 1\n", w);
1202                                } else if (w->node == fn) {
1203                                        RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1204                                        w->node = pn;
1205                                        w->state = nstate;
1206                                }
1207                        } else {
1208                                if (w->root == fn) {
1209                                        w->root = child;
1210                                        RT6_TRACE("W %p adjusted by delroot 2\n", w);
1211                                }
1212                                if (w->node == fn) {
1213                                        w->node = child;
1214                                        if (children&2) {
1215                                                RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1216                                                w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1217                                        } else {
1218                                                RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1219                                                w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1220                                        }
1221                                }
1222                        }
1223                }
1224                read_unlock(&fib6_walker_lock);
1225
1226                node_free(fn);
1227                if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1228                        return pn;
1229
1230                rt6_release(pn->leaf);
1231                pn->leaf = NULL;
1232                fn = pn;
1233        }
1234}
1235
1236static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1237                           struct nl_info *info)
1238{
1239        struct fib6_walker_t *w;
1240        struct rt6_info *rt = *rtp;
1241        struct net *net = info->nl_net;
1242
1243        RT6_TRACE("fib6_del_route\n");
1244
1245        /* Unlink it */
1246        *rtp = rt->dst.rt6_next;
1247        rt->rt6i_node = NULL;
1248        net->ipv6.rt6_stats->fib_rt_entries--;
1249        net->ipv6.rt6_stats->fib_discarded_routes++;
1250
1251        /* Reset round-robin state, if necessary */
1252        if (fn->rr_ptr == rt)
1253                fn->rr_ptr = NULL;
1254
1255        /* Remove this entry from other siblings */
1256        if (rt->rt6i_nsiblings) {
1257                struct rt6_info *sibling, *next_sibling;
1258
1259                list_for_each_entry_safe(sibling, next_sibling,
1260                                         &rt->rt6i_siblings, rt6i_siblings)
1261                        sibling->rt6i_nsiblings--;
1262                rt->rt6i_nsiblings = 0;
1263                list_del_init(&rt->rt6i_siblings);
1264        }
1265
1266        /* Adjust walkers */
1267        read_lock(&fib6_walker_lock);
1268        FOR_WALKERS(w) {
1269                if (w->state == FWS_C && w->leaf == rt) {
1270                        RT6_TRACE("walker %p adjusted by delroute\n", w);
1271                        w->leaf = rt->dst.rt6_next;
1272                        if (!w->leaf)
1273                                w->state = FWS_U;
1274                }
1275        }
1276        read_unlock(&fib6_walker_lock);
1277
1278        rt->dst.rt6_next = NULL;
1279
1280        /* If it was last route, expunge its radix tree node */
1281        if (!fn->leaf) {
1282                fn->fn_flags &= ~RTN_RTINFO;
1283                net->ipv6.rt6_stats->fib_route_nodes--;
1284                fn = fib6_repair_tree(net, fn);
1285        }
1286
1287        if (atomic_read(&rt->rt6i_ref) != 1) {
1288                /* This route is used as dummy address holder in some split
1289                 * nodes. It is not leaked, but it still holds other resources,
1290                 * which must be released in time. So, scan ascendant nodes
1291                 * and replace dummy references to this route with references
1292                 * to still alive ones.
1293                 */
1294                while (fn) {
1295                        if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
1296                                fn->leaf = fib6_find_prefix(net, fn);
1297                                atomic_inc(&fn->leaf->rt6i_ref);
1298                                rt6_release(rt);
1299                        }
1300                        fn = fn->parent;
1301                }
1302                /* No more references are possible at this point. */
1303                BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1304        }
1305
1306        inet6_rt_notify(RTM_DELROUTE, rt, info);
1307        rt6_release(rt);
1308}
1309
1310int fib6_del(struct rt6_info *rt, struct nl_info *info)
1311{
1312        struct net *net = info->nl_net;
1313        struct fib6_node *fn = rt->rt6i_node;
1314        struct rt6_info **rtp;
1315
1316#if RT6_DEBUG >= 2
1317        if (rt->dst.obsolete>0) {
1318                WARN_ON(fn != NULL);
1319                return -ENOENT;
1320        }
1321#endif
1322        if (!fn || rt == net->ipv6.ip6_null_entry)
1323                return -ENOENT;
1324
1325        WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1326
1327        if (!(rt->rt6i_flags & RTF_CACHE)) {
1328                struct fib6_node *pn = fn;
1329#ifdef CONFIG_IPV6_SUBTREES
1330                /* clones of this route might be in another subtree */
1331                if (rt->rt6i_src.plen) {
1332                        while (!(pn->fn_flags & RTN_ROOT))
1333                                pn = pn->parent;
1334                        pn = pn->parent;
1335                }
1336#endif
1337                fib6_prune_clones(info->nl_net, pn, rt);
1338        }
1339
1340        /*
1341         *      Walk the leaf entries looking for ourself
1342         */
1343
1344        for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1345                if (*rtp == rt) {
1346                        fib6_del_route(fn, rtp, info);
1347                        return 0;
1348                }
1349        }
1350        return -ENOENT;
1351}
1352
1353/*
1354 *      Tree traversal function.
1355 *
1356 *      Certainly, it is not interrupt safe.
1357 *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1358 *      It means, that we can modify tree during walking
1359 *      and use this function for garbage collection, clone pruning,
1360 *      cleaning tree when a device goes down etc. etc.
1361 *
1362 *      It guarantees that every node will be traversed,
1363 *      and that it will be traversed only once.
1364 *
1365 *      Callback function w->func may return:
1366 *      0 -> continue walking.
1367 *      positive value -> walking is suspended (used by tree dumps,
1368 *      and probably by gc, if it will be split to several slices)
1369 *      negative value -> terminate walking.
1370 *
1371 *      The function itself returns:
1372 *      0   -> walk is complete.
1373 *      >0  -> walk is incomplete (i.e. suspended)
1374 *      <0  -> walk is terminated by an error.
1375 */
1376
1377static int fib6_walk_continue(struct fib6_walker_t *w)
1378{
1379        struct fib6_node *fn, *pn;
1380
1381        for (;;) {
1382                fn = w->node;
1383                if (!fn)
1384                        return 0;
1385
1386                if (w->prune && fn != w->root &&
1387                    fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1388                        w->state = FWS_C;
1389                        w->leaf = fn->leaf;
1390                }
1391                switch (w->state) {
1392#ifdef CONFIG_IPV6_SUBTREES
1393                case FWS_S:
1394                        if (FIB6_SUBTREE(fn)) {
1395                                w->node = FIB6_SUBTREE(fn);
1396                                continue;
1397                        }
1398                        w->state = FWS_L;
1399#endif
1400                case FWS_L:
1401                        if (fn->left) {
1402                                w->node = fn->left;
1403                                w->state = FWS_INIT;
1404                                continue;
1405                        }
1406                        w->state = FWS_R;
1407                case FWS_R:
1408                        if (fn->right) {
1409                                w->node = fn->right;
1410                                w->state = FWS_INIT;
1411                                continue;
1412                        }
1413                        w->state = FWS_C;
1414                        w->leaf = fn->leaf;
1415                case FWS_C:
1416                        if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1417                                int err;
1418
1419                                if (w->skip) {
1420                                        w->skip--;
1421                                        continue;
1422                                }
1423
1424                                err = w->func(w);
1425                                if (err)
1426                                        return err;
1427
1428                                w->count++;
1429                                continue;
1430                        }
1431                        w->state = FWS_U;
1432                case FWS_U:
1433                        if (fn == w->root)
1434                                return 0;
1435                        pn = fn->parent;
1436                        w->node = pn;
1437#ifdef CONFIG_IPV6_SUBTREES
1438                        if (FIB6_SUBTREE(pn) == fn) {
1439                                WARN_ON(!(fn->fn_flags & RTN_ROOT));
1440                                w->state = FWS_L;
1441                                continue;
1442                        }
1443#endif
1444                        if (pn->left == fn) {
1445                                w->state = FWS_R;
1446                                continue;
1447                        }
1448                        if (pn->right == fn) {
1449                                w->state = FWS_C;
1450                                w->leaf = w->node->leaf;
1451                                continue;
1452                        }
1453#if RT6_DEBUG >= 2
1454                        WARN_ON(1);
1455#endif
1456                }
1457        }
1458}
1459
1460static int fib6_walk(struct fib6_walker_t *w)
1461{
1462        int res;
1463
1464        w->state = FWS_INIT;
1465        w->node = w->root;
1466
1467        fib6_walker_link(w);
1468        res = fib6_walk_continue(w);
1469        if (res <= 0)
1470                fib6_walker_unlink(w);
1471        return res;
1472}
1473
1474static int fib6_clean_node(struct fib6_walker_t *w)
1475{
1476        int res;
1477        struct rt6_info *rt;
1478        struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1479        struct nl_info info = {
1480                .nl_net = c->net,
1481        };
1482
1483        for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1484                res = c->func(rt, c->arg);
1485                if (res < 0) {
1486                        w->leaf = rt;
1487                        res = fib6_del(rt, &info);
1488                        if (res) {
1489#if RT6_DEBUG >= 2
1490                                pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1491                                         __func__, rt, rt->rt6i_node, res);
1492#endif
1493                                continue;
1494                        }
1495                        return 0;
1496                }
1497                WARN_ON(res != 0);
1498        }
1499        w->leaf = rt;
1500        return 0;
1501}
1502
1503/*
1504 *      Convenient frontend to tree walker.
1505 *
1506 *      func is called on each route.
1507 *              It may return -1 -> delete this route.
1508 *                            0  -> continue walking
1509 *
1510 *      prune==1 -> only immediate children of node (certainly,
1511 *      ignoring pure split nodes) will be scanned.
1512 */
1513
1514static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1515                            int (*func)(struct rt6_info *, void *arg),
1516                            int prune, void *arg)
1517{
1518        struct fib6_cleaner_t c;
1519
1520        c.w.root = root;
1521        c.w.func = fib6_clean_node;
1522        c.w.prune = prune;
1523        c.w.count = 0;
1524        c.w.skip = 0;
1525        c.func = func;
1526        c.arg = arg;
1527        c.net = net;
1528
1529        fib6_walk(&c.w);
1530}
1531
1532void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
1533                    void *arg)
1534{
1535        struct fib6_table *table;
1536        struct hlist_head *head;
1537        unsigned int h;
1538
1539        rcu_read_lock();
1540        for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1541                head = &net->ipv6.fib_table_hash[h];
1542                hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1543                        write_lock_bh(&table->tb6_lock);
1544                        fib6_clean_tree(net, &table->tb6_root,
1545                                        func, 0, arg);
1546                        write_unlock_bh(&table->tb6_lock);
1547                }
1548        }
1549        rcu_read_unlock();
1550}
1551
1552static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1553{
1554        if (rt->rt6i_flags & RTF_CACHE) {
1555                RT6_TRACE("pruning clone %p\n", rt);
1556                return -1;
1557        }
1558
1559        return 0;
1560}
1561
1562static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
1563                              struct rt6_info *rt)
1564{
1565        fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
1566}
1567
1568/*
1569 *      Garbage collection
1570 */
1571
1572static struct fib6_gc_args
1573{
1574        int                     timeout;
1575        int                     more;
1576} gc_args;
1577
1578static int fib6_age(struct rt6_info *rt, void *arg)
1579{
1580        unsigned long now = jiffies;
1581
1582        /*
1583         *      check addrconf expiration here.
1584         *      Routes are expired even if they are in use.
1585         *
1586         *      Also age clones. Note, that clones are aged out
1587         *      only if they are not in use now.
1588         */
1589
1590        if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1591                if (time_after(now, rt->dst.expires)) {
1592                        RT6_TRACE("expiring %p\n", rt);
1593                        return -1;
1594                }
1595                gc_args.more++;
1596        } else if (rt->rt6i_flags & RTF_CACHE) {
1597                if (atomic_read(&rt->dst.__refcnt) == 0 &&
1598                    time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
1599                        RT6_TRACE("aging clone %p\n", rt);
1600                        return -1;
1601                } else if (rt->rt6i_flags & RTF_GATEWAY) {
1602                        struct neighbour *neigh;
1603                        __u8 neigh_flags = 0;
1604
1605                        neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1606                        if (neigh) {
1607                                neigh_flags = neigh->flags;
1608                                neigh_release(neigh);
1609                        }
1610                        if (!(neigh_flags & NTF_ROUTER)) {
1611                                RT6_TRACE("purging route %p via non-router but gateway\n",
1612                                          rt);
1613                                return -1;
1614                        }
1615                }
1616                gc_args.more++;
1617        }
1618
1619        return 0;
1620}
1621
1622static DEFINE_SPINLOCK(fib6_gc_lock);
1623
1624void fib6_run_gc(unsigned long expires, struct net *net, bool force)
1625{
1626        unsigned long now;
1627
1628        if (force) {
1629                spin_lock_bh(&fib6_gc_lock);
1630        } else if (!spin_trylock_bh(&fib6_gc_lock)) {
1631                mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1632                return;
1633        }
1634        gc_args.timeout = expires ? (int)expires :
1635                          net->ipv6.sysctl.ip6_rt_gc_interval;
1636
1637        gc_args.more = icmp6_dst_gc();
1638
1639        fib6_clean_all(net, fib6_age, NULL);
1640        now = jiffies;
1641        net->ipv6.ip6_rt_last_gc = now;
1642
1643        if (gc_args.more)
1644                mod_timer(&net->ipv6.ip6_fib_timer,
1645                          round_jiffies(now
1646                                        + net->ipv6.sysctl.ip6_rt_gc_interval));
1647        else
1648                del_timer(&net->ipv6.ip6_fib_timer);
1649        spin_unlock_bh(&fib6_gc_lock);
1650}
1651
1652static void fib6_gc_timer_cb(unsigned long arg)
1653{
1654        fib6_run_gc(0, (struct net *)arg, true);
1655}
1656
1657static int __net_init fib6_net_init(struct net *net)
1658{
1659        size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1660
1661        setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1662
1663        net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1664        if (!net->ipv6.rt6_stats)
1665                goto out_timer;
1666
1667        /* Avoid false sharing : Use at least a full cache line */
1668        size = max_t(size_t, size, L1_CACHE_BYTES);
1669
1670        net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1671        if (!net->ipv6.fib_table_hash)
1672                goto out_rt6_stats;
1673
1674        net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1675                                          GFP_KERNEL);
1676        if (!net->ipv6.fib6_main_tbl)
1677                goto out_fib_table_hash;
1678
1679        net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1680        net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1681        net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1682                RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1683        inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1684
1685#ifdef CONFIG_IPV6_MULTIPLE_TABLES
1686        net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1687                                           GFP_KERNEL);
1688        if (!net->ipv6.fib6_local_tbl)
1689                goto out_fib6_main_tbl;
1690        net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1691        net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1692        net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1693                RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1694        inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1695#endif
1696        fib6_tables_init(net);
1697
1698        return 0;
1699
1700#ifdef CONFIG_IPV6_MULTIPLE_TABLES
1701out_fib6_main_tbl:
1702        kfree(net->ipv6.fib6_main_tbl);
1703#endif
1704out_fib_table_hash:
1705        kfree(net->ipv6.fib_table_hash);
1706out_rt6_stats:
1707        kfree(net->ipv6.rt6_stats);
1708out_timer:
1709        return -ENOMEM;
1710 }
1711
1712static void fib6_net_exit(struct net *net)
1713{
1714        rt6_ifdown(net, NULL);
1715        del_timer_sync(&net->ipv6.ip6_fib_timer);
1716
1717#ifdef CONFIG_IPV6_MULTIPLE_TABLES
1718        inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1719        kfree(net->ipv6.fib6_local_tbl);
1720#endif
1721        inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1722        kfree(net->ipv6.fib6_main_tbl);
1723        kfree(net->ipv6.fib_table_hash);
1724        kfree(net->ipv6.rt6_stats);
1725}
1726
1727static struct pernet_operations fib6_net_ops = {
1728        .init = fib6_net_init,
1729        .exit = fib6_net_exit,
1730};
1731
1732int __init fib6_init(void)
1733{
1734        int ret = -ENOMEM;
1735
1736        fib6_node_kmem = kmem_cache_create("fib6_nodes",
1737                                           sizeof(struct fib6_node),
1738                                           0, SLAB_HWCACHE_ALIGN,
1739                                           NULL);
1740        if (!fib6_node_kmem)
1741                goto out;
1742
1743        ret = register_pernet_subsys(&fib6_net_ops);
1744        if (ret)
1745                goto out_kmem_cache_create;
1746
1747        ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1748                              NULL);
1749        if (ret)
1750                goto out_unregister_subsys;
1751out:
1752        return ret;
1753
1754out_unregister_subsys:
1755        unregister_pernet_subsys(&fib6_net_ops);
1756out_kmem_cache_create:
1757        kmem_cache_destroy(fib6_node_kmem);
1758        goto out;
1759}
1760
1761void fib6_gc_cleanup(void)
1762{
1763        unregister_pernet_subsys(&fib6_net_ops);
1764        kmem_cache_destroy(fib6_node_kmem);
1765}
1766
1767#ifdef CONFIG_PROC_FS
1768
1769struct ipv6_route_iter {
1770        struct seq_net_private p;
1771        struct fib6_walker_t w;
1772        loff_t skip;
1773        struct fib6_table *tbl;
1774        __u32 sernum;
1775};
1776
1777static int ipv6_route_seq_show(struct seq_file *seq, void *v)
1778{
1779        struct rt6_info *rt = v;
1780        struct ipv6_route_iter *iter = seq->private;
1781
1782        seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
1783
1784#ifdef CONFIG_IPV6_SUBTREES
1785        seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
1786#else
1787        seq_puts(seq, "00000000000000000000000000000000 00 ");
1788#endif
1789        if (rt->rt6i_flags & RTF_GATEWAY)
1790                seq_printf(seq, "%pi6", &rt->rt6i_gateway);
1791        else
1792                seq_puts(seq, "00000000000000000000000000000000");
1793
1794        seq_printf(seq, " %08x %08x %08x %08x %8s\n",
1795                   rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
1796                   rt->dst.__use, rt->rt6i_flags,
1797                   rt->dst.dev ? rt->dst.dev->name : "");
1798        iter->w.leaf = NULL;
1799        return 0;
1800}
1801
1802static int ipv6_route_yield(struct fib6_walker_t *w)
1803{
1804        struct ipv6_route_iter *iter = w->args;
1805
1806        if (!iter->skip)
1807                return 1;
1808
1809        do {
1810                iter->w.leaf = iter->w.leaf->dst.rt6_next;
1811                iter->skip--;
1812                if (!iter->skip && iter->w.leaf)
1813                        return 1;
1814        } while (iter->w.leaf);
1815
1816        return 0;
1817}
1818
1819static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter)
1820{
1821        memset(&iter->w, 0, sizeof(iter->w));
1822        iter->w.func = ipv6_route_yield;
1823        iter->w.root = &iter->tbl->tb6_root;
1824        iter->w.state = FWS_INIT;
1825        iter->w.node = iter->w.root;
1826        iter->w.args = iter;
1827        iter->sernum = iter->w.root->fn_sernum;
1828        INIT_LIST_HEAD(&iter->w.lh);
1829        fib6_walker_link(&iter->w);
1830}
1831
1832static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
1833                                                    struct net *net)
1834{
1835        unsigned int h;
1836        struct hlist_node *node;
1837
1838        if (tbl) {
1839                h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
1840                node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
1841        } else {
1842                h = 0;
1843                node = NULL;
1844        }
1845
1846        while (!node && h < FIB6_TABLE_HASHSZ) {
1847                node = rcu_dereference_bh(
1848                        hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
1849        }
1850        return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
1851}
1852
1853static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
1854{
1855        if (iter->sernum != iter->w.root->fn_sernum) {
1856                iter->sernum = iter->w.root->fn_sernum;
1857                iter->w.state = FWS_INIT;
1858                iter->w.node = iter->w.root;
1859                WARN_ON(iter->w.skip);
1860                iter->w.skip = iter->w.count;
1861        }
1862}
1863
1864static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1865{
1866        int r;
1867        struct rt6_info *n;
1868        struct net *net = seq_file_net(seq);
1869        struct ipv6_route_iter *iter = seq->private;
1870
1871        if (!v)
1872                goto iter_table;
1873
1874        n = ((struct rt6_info *)v)->dst.rt6_next;
1875        if (n) {
1876                ++*pos;
1877                return n;
1878        }
1879
1880iter_table:
1881        ipv6_route_check_sernum(iter);
1882        read_lock(&iter->tbl->tb6_lock);
1883        r = fib6_walk_continue(&iter->w);
1884        read_unlock(&iter->tbl->tb6_lock);
1885        if (r > 0) {
1886                if (v)
1887                        ++*pos;
1888                return iter->w.leaf;
1889        } else if (r < 0) {
1890                fib6_walker_unlink(&iter->w);
1891                return NULL;
1892        }
1893        fib6_walker_unlink(&iter->w);
1894
1895        iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
1896        if (!iter->tbl)
1897                return NULL;
1898
1899        ipv6_route_seq_setup_walk(iter);
1900        goto iter_table;
1901}
1902
1903static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
1904        __acquires(RCU_BH)
1905{
1906        struct net *net = seq_file_net(seq);
1907        struct ipv6_route_iter *iter = seq->private;
1908
1909        rcu_read_lock_bh();
1910        iter->tbl = ipv6_route_seq_next_table(NULL, net);
1911        iter->skip = *pos;
1912
1913        if (iter->tbl) {
1914                ipv6_route_seq_setup_walk(iter);
1915                return ipv6_route_seq_next(seq, NULL, pos);
1916        } else {
1917                return NULL;
1918        }
1919}
1920
1921static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
1922{
1923        struct fib6_walker_t *w = &iter->w;
1924        return w->node && !(w->state == FWS_U && w->node == w->root);
1925}
1926
1927static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
1928        __releases(RCU_BH)
1929{
1930        struct ipv6_route_iter *iter = seq->private;
1931
1932        if (ipv6_route_iter_active(iter))
1933                fib6_walker_unlink(&iter->w);
1934
1935        rcu_read_unlock_bh();
1936}
1937
1938static const struct seq_operations ipv6_route_seq_ops = {
1939        .start  = ipv6_route_seq_start,
1940        .next   = ipv6_route_seq_next,
1941        .stop   = ipv6_route_seq_stop,
1942        .show   = ipv6_route_seq_show
1943};
1944
1945int ipv6_route_open(struct inode *inode, struct file *file)
1946{
1947        return seq_open_net(inode, file, &ipv6_route_seq_ops,
1948                            sizeof(struct ipv6_route_iter));
1949}
1950
1951#endif /* CONFIG_PROC_FS */
1952