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TOMOYO Linux Cross Reference
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 
 49 static struct kmem_cache * fib6_node_kmem __read_mostly;
 50 
 51 enum fib_walk_state_t
 52 {
 53 #ifdef CONFIG_IPV6_SUBTREES
 54         FWS_S,
 55 #endif
 56         FWS_L,
 57         FWS_R,
 58         FWS_C,
 59         FWS_U
 60 };
 61 
 62 struct fib6_cleaner_t
 63 {
 64         struct fib6_walker_t w;
 65         struct net *net;
 66         int (*func)(struct rt6_info *, void *arg);
 67         void *arg;
 68 };
 69 
 70 static DEFINE_RWLOCK(fib6_walker_lock);
 71 
 72 #ifdef CONFIG_IPV6_SUBTREES
 73 #define FWS_INIT FWS_S
 74 #else
 75 #define FWS_INIT FWS_L
 76 #endif
 77 
 78 static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
 79                               struct rt6_info *rt);
 80 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
 81 static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
 82 static int fib6_walk(struct fib6_walker_t *w);
 83 static int fib6_walk_continue(struct fib6_walker_t *w);
 84 
 85 /*
 86  *      A routing update causes an increase of the serial number on the
 87  *      affected subtree. This allows for cached routes to be asynchronously
 88  *      tested when modifications are made to the destination cache as a
 89  *      result of redirects, path MTU changes, etc.
 90  */
 91 
 92 static __u32 rt_sernum;
 93 
 94 static void fib6_gc_timer_cb(unsigned long arg);
 95 
 96 static LIST_HEAD(fib6_walkers);
 97 #define FOR_WALKERS(w) list_for_each_entry(w, &fib6_walkers, lh)
 98 
 99 static inline void fib6_walker_link(struct fib6_walker_t *w)
100 {
101         write_lock_bh(&fib6_walker_lock);
102         list_add(&w->lh, &fib6_walkers);
103         write_unlock_bh(&fib6_walker_lock);
104 }
105 
106 static inline void fib6_walker_unlink(struct fib6_walker_t *w)
107 {
108         write_lock_bh(&fib6_walker_lock);
109         list_del(&w->lh);
110         write_unlock_bh(&fib6_walker_lock);
111 }
112 static __inline__ u32 fib6_new_sernum(void)
113 {
114         u32 n = ++rt_sernum;
115         if ((__s32)n <= 0)
116                 rt_sernum = n = 1;
117         return n;
118 }
119 
120 /*
121  *      Auxiliary address test functions for the radix tree.
122  *
123  *      These assume a 32bit processor (although it will work on
124  *      64bit processors)
125  */
126 
127 /*
128  *      test bit
129  */
130 #if defined(__LITTLE_ENDIAN)
131 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
132 #else
133 # define BITOP_BE32_SWIZZLE     0
134 #endif
135 
136 static __inline__ __be32 addr_bit_set(const void *token, int fn_bit)
137 {
138         const __be32 *addr = token;
139         /*
140          * Here,
141          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
142          * is optimized version of
143          *      htonl(1 << ((~fn_bit)&0x1F))
144          * See include/asm-generic/bitops/le.h.
145          */
146         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
147                addr[fn_bit >> 5];
148 }
149 
150 static __inline__ struct fib6_node * node_alloc(void)
151 {
152         struct fib6_node *fn;
153 
154         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
155 
156         return fn;
157 }
158 
159 static __inline__ void node_free(struct fib6_node * fn)
160 {
161         kmem_cache_free(fib6_node_kmem, fn);
162 }
163 
164 static __inline__ void rt6_release(struct rt6_info *rt)
165 {
166         if (atomic_dec_and_test(&rt->rt6i_ref))
167                 dst_free(&rt->dst);
168 }
169 
170 static void fib6_link_table(struct net *net, struct fib6_table *tb)
171 {
172         unsigned int h;
173 
174         /*
175          * Initialize table lock at a single place to give lockdep a key,
176          * tables aren't visible prior to being linked to the list.
177          */
178         rwlock_init(&tb->tb6_lock);
179 
180         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
181 
182         /*
183          * No protection necessary, this is the only list mutatation
184          * operation, tables never disappear once they exist.
185          */
186         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
187 }
188 
189 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
190 
191 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
192 {
193         struct fib6_table *table;
194 
195         table = kzalloc(sizeof(*table), GFP_ATOMIC);
196         if (table) {
197                 table->tb6_id = id;
198                 table->tb6_root.leaf = net->ipv6.ip6_null_entry;
199                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
200                 inet_peer_base_init(&table->tb6_peers);
201         }
202 
203         return table;
204 }
205 
206 struct fib6_table *fib6_new_table(struct net *net, u32 id)
207 {
208         struct fib6_table *tb;
209 
210         if (id == 0)
211                 id = RT6_TABLE_MAIN;
212         tb = fib6_get_table(net, id);
213         if (tb)
214                 return tb;
215 
216         tb = fib6_alloc_table(net, id);
217         if (tb)
218                 fib6_link_table(net, tb);
219 
220         return tb;
221 }
222 
223 struct fib6_table *fib6_get_table(struct net *net, u32 id)
224 {
225         struct fib6_table *tb;
226         struct hlist_head *head;
227         struct hlist_node *node;
228         unsigned int h;
229 
230         if (id == 0)
231                 id = RT6_TABLE_MAIN;
232         h = id & (FIB6_TABLE_HASHSZ - 1);
233         rcu_read_lock();
234         head = &net->ipv6.fib_table_hash[h];
235         hlist_for_each_entry_rcu(tb, node, head, tb6_hlist) {
236                 if (tb->tb6_id == id) {
237                         rcu_read_unlock();
238                         return tb;
239                 }
240         }
241         rcu_read_unlock();
242 
243         return NULL;
244 }
245 
246 static void __net_init fib6_tables_init(struct net *net)
247 {
248         fib6_link_table(net, net->ipv6.fib6_main_tbl);
249         fib6_link_table(net, net->ipv6.fib6_local_tbl);
250 }
251 #else
252 
253 struct fib6_table *fib6_new_table(struct net *net, u32 id)
254 {
255         return fib6_get_table(net, id);
256 }
257 
258 struct fib6_table *fib6_get_table(struct net *net, u32 id)
259 {
260           return net->ipv6.fib6_main_tbl;
261 }
262 
263 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
264                                    int flags, pol_lookup_t lookup)
265 {
266         return (struct dst_entry *) lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
267 }
268 
269 static void __net_init fib6_tables_init(struct net *net)
270 {
271         fib6_link_table(net, net->ipv6.fib6_main_tbl);
272 }
273 
274 #endif
275 
276 static int fib6_dump_node(struct fib6_walker_t *w)
277 {
278         int res;
279         struct rt6_info *rt;
280 
281         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
282                 res = rt6_dump_route(rt, w->args);
283                 if (res < 0) {
284                         /* Frame is full, suspend walking */
285                         w->leaf = rt;
286                         return 1;
287                 }
288                 WARN_ON(res == 0);
289         }
290         w->leaf = NULL;
291         return 0;
292 }
293 
294 static void fib6_dump_end(struct netlink_callback *cb)
295 {
296         struct fib6_walker_t *w = (void*)cb->args[2];
297 
298         if (w) {
299                 if (cb->args[4]) {
300                         cb->args[4] = 0;
301                         fib6_walker_unlink(w);
302                 }
303                 cb->args[2] = 0;
304                 kfree(w);
305         }
306         cb->done = (void*)cb->args[3];
307         cb->args[1] = 3;
308 }
309 
310 static int fib6_dump_done(struct netlink_callback *cb)
311 {
312         fib6_dump_end(cb);
313         return cb->done ? cb->done(cb) : 0;
314 }
315 
316 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
317                            struct netlink_callback *cb)
318 {
319         struct fib6_walker_t *w;
320         int res;
321 
322         w = (void *)cb->args[2];
323         w->root = &table->tb6_root;
324 
325         if (cb->args[4] == 0) {
326                 w->count = 0;
327                 w->skip = 0;
328 
329                 read_lock_bh(&table->tb6_lock);
330                 res = fib6_walk(w);
331                 read_unlock_bh(&table->tb6_lock);
332                 if (res > 0) {
333                         cb->args[4] = 1;
334                         cb->args[5] = w->root->fn_sernum;
335                 }
336         } else {
337                 if (cb->args[5] != w->root->fn_sernum) {
338                         /* Begin at the root if the tree changed */
339                         cb->args[5] = w->root->fn_sernum;
340                         w->state = FWS_INIT;
341                         w->node = w->root;
342                         w->skip = w->count;
343                 } else
344                         w->skip = 0;
345 
346                 read_lock_bh(&table->tb6_lock);
347                 res = fib6_walk_continue(w);
348                 read_unlock_bh(&table->tb6_lock);
349                 if (res <= 0) {
350                         fib6_walker_unlink(w);
351                         cb->args[4] = 0;
352                 }
353         }
354 
355         return res;
356 }
357 
358 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
359 {
360         struct net *net = sock_net(skb->sk);
361         unsigned int h, s_h;
362         unsigned int e = 0, s_e;
363         struct rt6_rtnl_dump_arg arg;
364         struct fib6_walker_t *w;
365         struct fib6_table *tb;
366         struct hlist_node *node;
367         struct hlist_head *head;
368         int res = 0;
369 
370         s_h = cb->args[0];
371         s_e = cb->args[1];
372 
373         w = (void *)cb->args[2];
374         if (!w) {
375                 /* New dump:
376                  *
377                  * 1. hook callback destructor.
378                  */
379                 cb->args[3] = (long)cb->done;
380                 cb->done = fib6_dump_done;
381 
382                 /*
383                  * 2. allocate and initialize walker.
384                  */
385                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
386                 if (!w)
387                         return -ENOMEM;
388                 w->func = fib6_dump_node;
389                 cb->args[2] = (long)w;
390         }
391 
392         arg.skb = skb;
393         arg.cb = cb;
394         arg.net = net;
395         w->args = &arg;
396 
397         rcu_read_lock();
398         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
399                 e = 0;
400                 head = &net->ipv6.fib_table_hash[h];
401                 hlist_for_each_entry_rcu(tb, node, head, tb6_hlist) {
402                         if (e < s_e)
403                                 goto next;
404                         res = fib6_dump_table(tb, skb, cb);
405                         if (res != 0)
406                                 goto out;
407 next:
408                         e++;
409                 }
410         }
411 out:
412         rcu_read_unlock();
413         cb->args[1] = e;
414         cb->args[0] = h;
415 
416         res = res < 0 ? res : skb->len;
417         if (res <= 0)
418                 fib6_dump_end(cb);
419         return res;
420 }
421 
422 /*
423  *      Routing Table
424  *
425  *      return the appropriate node for a routing tree "add" operation
426  *      by either creating and inserting or by returning an existing
427  *      node.
428  */
429 
430 static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
431                                      int addrlen, int plen,
432                                      int offset, int allow_create,
433                                      int replace_required)
434 {
435         struct fib6_node *fn, *in, *ln;
436         struct fib6_node *pn = NULL;
437         struct rt6key *key;
438         int     bit;
439         __be32  dir = 0;
440         __u32   sernum = fib6_new_sernum();
441 
442         RT6_TRACE("fib6_add_1\n");
443 
444         /* insert node in tree */
445 
446         fn = root;
447 
448         do {
449                 key = (struct rt6key *)((u8 *)fn->leaf + offset);
450 
451                 /*
452                  *      Prefix match
453                  */
454                 if (plen < fn->fn_bit ||
455                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
456                         if (!allow_create) {
457                                 if (replace_required) {
458                                         pr_warn("Can't replace route, no match found\n");
459                                         return ERR_PTR(-ENOENT);
460                                 }
461                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
462                         }
463                         goto insert_above;
464                 }
465 
466                 /*
467                  *      Exact match ?
468                  */
469 
470                 if (plen == fn->fn_bit) {
471                         /* clean up an intermediate node */
472                         if (!(fn->fn_flags & RTN_RTINFO)) {
473                                 rt6_release(fn->leaf);
474                                 fn->leaf = NULL;
475                         }
476 
477                         fn->fn_sernum = sernum;
478 
479                         return fn;
480                 }
481 
482                 /*
483                  *      We have more bits to go
484                  */
485 
486                 /* Try to walk down on tree. */
487                 fn->fn_sernum = sernum;
488                 dir = addr_bit_set(addr, fn->fn_bit);
489                 pn = fn;
490                 fn = dir ? fn->right: fn->left;
491         } while (fn);
492 
493         if (!allow_create) {
494                 /* We should not create new node because
495                  * NLM_F_REPLACE was specified without NLM_F_CREATE
496                  * I assume it is safe to require NLM_F_CREATE when
497                  * REPLACE flag is used! Later we may want to remove the
498                  * check for replace_required, because according
499                  * to netlink specification, NLM_F_CREATE
500                  * MUST be specified if new route is created.
501                  * That would keep IPv6 consistent with IPv4
502                  */
503                 if (replace_required) {
504                         pr_warn("Can't replace route, no match found\n");
505                         return ERR_PTR(-ENOENT);
506                 }
507                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
508         }
509         /*
510          *      We walked to the bottom of tree.
511          *      Create new leaf node without children.
512          */
513 
514         ln = node_alloc();
515 
516         if (!ln)
517                 return ERR_PTR(-ENOMEM);
518         ln->fn_bit = plen;
519 
520         ln->parent = pn;
521         ln->fn_sernum = sernum;
522 
523         if (dir)
524                 pn->right = ln;
525         else
526                 pn->left  = ln;
527 
528         return ln;
529 
530 
531 insert_above:
532         /*
533          * split since we don't have a common prefix anymore or
534          * we have a less significant route.
535          * we've to insert an intermediate node on the list
536          * this new node will point to the one we need to create
537          * and the current
538          */
539 
540         pn = fn->parent;
541 
542         /* find 1st bit in difference between the 2 addrs.
543 
544            See comment in __ipv6_addr_diff: bit may be an invalid value,
545            but if it is >= plen, the value is ignored in any case.
546          */
547 
548         bit = __ipv6_addr_diff(addr, &key->addr, addrlen);
549 
550         /*
551          *              (intermediate)[in]
552          *                /        \
553          *      (new leaf node)[ln] (old node)[fn]
554          */
555         if (plen > bit) {
556                 in = node_alloc();
557                 ln = node_alloc();
558 
559                 if (!in || !ln) {
560                         if (in)
561                                 node_free(in);
562                         if (ln)
563                                 node_free(ln);
564                         return ERR_PTR(-ENOMEM);
565                 }
566 
567                 /*
568                  * new intermediate node.
569                  * RTN_RTINFO will
570                  * be off since that an address that chooses one of
571                  * the branches would not match less specific routes
572                  * in the other branch
573                  */
574 
575                 in->fn_bit = bit;
576 
577                 in->parent = pn;
578                 in->leaf = fn->leaf;
579                 atomic_inc(&in->leaf->rt6i_ref);
580 
581                 in->fn_sernum = sernum;
582 
583                 /* update parent pointer */
584                 if (dir)
585                         pn->right = in;
586                 else
587                         pn->left  = in;
588 
589                 ln->fn_bit = plen;
590 
591                 ln->parent = in;
592                 fn->parent = in;
593 
594                 ln->fn_sernum = sernum;
595 
596                 if (addr_bit_set(addr, bit)) {
597                         in->right = ln;
598                         in->left  = fn;
599                 } else {
600                         in->left  = ln;
601                         in->right = fn;
602                 }
603         } else { /* plen <= bit */
604 
605                 /*
606                  *              (new leaf node)[ln]
607                  *                /        \
608                  *           (old node)[fn] NULL
609                  */
610 
611                 ln = node_alloc();
612 
613                 if (!ln)
614                         return ERR_PTR(-ENOMEM);
615 
616                 ln->fn_bit = plen;
617 
618                 ln->parent = pn;
619 
620                 ln->fn_sernum = sernum;
621 
622                 if (dir)
623                         pn->right = ln;
624                 else
625                         pn->left  = ln;
626 
627                 if (addr_bit_set(&key->addr, plen))
628                         ln->right = fn;
629                 else
630                         ln->left  = fn;
631 
632                 fn->parent = ln;
633         }
634         return ln;
635 }
636 
637 /*
638  *      Insert routing information in a node.
639  */
640 
641 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
642                             struct nl_info *info)
643 {
644         struct rt6_info *iter = NULL;
645         struct rt6_info **ins;
646         int replace = (info->nlh &&
647                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
648         int add = (!info->nlh ||
649                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
650         int found = 0;
651 
652         ins = &fn->leaf;
653 
654         for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
655                 /*
656                  *      Search for duplicates
657                  */
658 
659                 if (iter->rt6i_metric == rt->rt6i_metric) {
660                         /*
661                          *      Same priority level
662                          */
663                         if (info->nlh &&
664                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
665                                 return -EEXIST;
666                         if (replace) {
667                                 found++;
668                                 break;
669                         }
670 
671                         if (iter->dst.dev == rt->dst.dev &&
672                             iter->rt6i_idev == rt->rt6i_idev &&
673                             ipv6_addr_equal(&iter->rt6i_gateway,
674                                             &rt->rt6i_gateway)) {
675                                 if (!(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 
702 add:
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 
737 static __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 
745 void 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 
758 int 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 
859 out:
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          */
889 st_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 
902 struct lookup_args {
903         int                     offset;         /* key offset on rt6_info       */
904         const struct in6_addr   *addr;          /* search key                   */
905 };
906 
907 static 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 
962 struct 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 
995 static 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 
1025 struct 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 
1055 static 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 
1076 static 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 
1177 static 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 
1240 int 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 
1307 static 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 
1390 static 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 
1404 static 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 
1444 static 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 
1462 void 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 }
1482 void 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 
1503 static 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 
1513 static 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 
1523 static struct fib6_gc_args
1524 {
1525         int                     timeout;
1526         int                     more;
1527 } gc_args;
1528 
1529 static 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 
1573 static DEFINE_SPINLOCK(fib6_gc_lock);
1574 
1575 void 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 
1602 static void fib6_gc_timer_cb(unsigned long arg)
1603 {
1604         fib6_run_gc(0, (struct net *)arg);
1605 }
1606 
1607 static 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
1651 out_fib6_main_tbl:
1652         kfree(net->ipv6.fib6_main_tbl);
1653 #endif
1654 out_fib_table_hash:
1655         kfree(net->ipv6.fib_table_hash);
1656 out_rt6_stats:
1657         kfree(net->ipv6.rt6_stats);
1658 out_timer:
1659         return -ENOMEM;
1660  }
1661 
1662 static 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 
1677 static struct pernet_operations fib6_net_ops = {
1678         .init = fib6_net_init,
1679         .exit = fib6_net_exit,
1680 };
1681 
1682 int __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;
1701 out:
1702         return ret;
1703 
1704 out_unregister_subsys:
1705         unregister_pernet_subsys(&fib6_net_ops);
1706 out_kmem_cache_create:
1707         kmem_cache_destroy(fib6_node_kmem);
1708         goto out;
1709 }
1710 
1711 void 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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