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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  *      Changes:
 14  *      Yuji SEKIYA @USAGI:     Support default route on router node;
 15  *                              remove ip6_null_entry from the top of
 16  *                              routing table.
 17  *      Ville Nuorvala:         Fixed routing subtrees.
 18  */
 19 
 20 #define pr_fmt(fmt) "IPv6: " fmt
 21 
 22 #include <linux/errno.h>
 23 #include <linux/types.h>
 24 #include <linux/net.h>
 25 #include <linux/route.h>
 26 #include <linux/netdevice.h>
 27 #include <linux/in6.h>
 28 #include <linux/init.h>
 29 #include <linux/list.h>
 30 #include <linux/slab.h>
 31 
 32 #include <net/ipv6.h>
 33 #include <net/ndisc.h>
 34 #include <net/addrconf.h>
 35 #include <net/lwtunnel.h>
 36 #include <net/fib_notifier.h>
 37 
 38 #include <net/ip6_fib.h>
 39 #include <net/ip6_route.h>
 40 
 41 static struct kmem_cache *fib6_node_kmem __read_mostly;
 42 
 43 struct fib6_cleaner {
 44         struct fib6_walker w;
 45         struct net *net;
 46         int (*func)(struct rt6_info *, void *arg);
 47         int sernum;
 48         void *arg;
 49 };
 50 
 51 #ifdef CONFIG_IPV6_SUBTREES
 52 #define FWS_INIT FWS_S
 53 #else
 54 #define FWS_INIT FWS_L
 55 #endif
 56 
 57 static struct rt6_info *fib6_find_prefix(struct net *net,
 58                                          struct fib6_table *table,
 59                                          struct fib6_node *fn);
 60 static struct fib6_node *fib6_repair_tree(struct net *net,
 61                                           struct fib6_table *table,
 62                                           struct fib6_node *fn);
 63 static int fib6_walk(struct net *net, struct fib6_walker *w);
 64 static int fib6_walk_continue(struct fib6_walker *w);
 65 
 66 /*
 67  *      A routing update causes an increase of the serial number on the
 68  *      affected subtree. This allows for cached routes to be asynchronously
 69  *      tested when modifications are made to the destination cache as a
 70  *      result of redirects, path MTU changes, etc.
 71  */
 72 
 73 static void fib6_gc_timer_cb(struct timer_list *t);
 74 
 75 #define FOR_WALKERS(net, w) \
 76         list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)
 77 
 78 static void fib6_walker_link(struct net *net, struct fib6_walker *w)
 79 {
 80         write_lock_bh(&net->ipv6.fib6_walker_lock);
 81         list_add(&w->lh, &net->ipv6.fib6_walkers);
 82         write_unlock_bh(&net->ipv6.fib6_walker_lock);
 83 }
 84 
 85 static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
 86 {
 87         write_lock_bh(&net->ipv6.fib6_walker_lock);
 88         list_del(&w->lh);
 89         write_unlock_bh(&net->ipv6.fib6_walker_lock);
 90 }
 91 
 92 static int fib6_new_sernum(struct net *net)
 93 {
 94         int new, old;
 95 
 96         do {
 97                 old = atomic_read(&net->ipv6.fib6_sernum);
 98                 new = old < INT_MAX ? old + 1 : 1;
 99         } while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
100                                 old, new) != old);
101         return new;
102 }
103 
104 enum {
105         FIB6_NO_SERNUM_CHANGE = 0,
106 };
107 
108 void fib6_update_sernum(struct rt6_info *rt)
109 {
110         struct net *net = dev_net(rt->dst.dev);
111         struct fib6_node *fn;
112 
113         fn = rcu_dereference_protected(rt->rt6i_node,
114                         lockdep_is_held(&rt->rt6i_table->tb6_lock));
115         if (fn)
116                 fn->fn_sernum = fib6_new_sernum(net);
117 }
118 
119 /*
120  *      Auxiliary address test functions for the radix tree.
121  *
122  *      These assume a 32bit processor (although it will work on
123  *      64bit processors)
124  */
125 
126 /*
127  *      test bit
128  */
129 #if defined(__LITTLE_ENDIAN)
130 # define BITOP_BE32_SWIZZLE     (0x1F & ~7)
131 #else
132 # define BITOP_BE32_SWIZZLE     0
133 #endif
134 
135 static __be32 addr_bit_set(const void *token, int fn_bit)
136 {
137         const __be32 *addr = token;
138         /*
139          * Here,
140          *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
141          * is optimized version of
142          *      htonl(1 << ((~fn_bit)&0x1F))
143          * See include/asm-generic/bitops/le.h.
144          */
145         return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
146                addr[fn_bit >> 5];
147 }
148 
149 static struct fib6_node *node_alloc(struct net *net)
150 {
151         struct fib6_node *fn;
152 
153         fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
154         if (fn)
155                 net->ipv6.rt6_stats->fib_nodes++;
156 
157         return fn;
158 }
159 
160 static void node_free_immediate(struct net *net, struct fib6_node *fn)
161 {
162         kmem_cache_free(fib6_node_kmem, fn);
163         net->ipv6.rt6_stats->fib_nodes--;
164 }
165 
166 static void node_free_rcu(struct rcu_head *head)
167 {
168         struct fib6_node *fn = container_of(head, struct fib6_node, rcu);
169 
170         kmem_cache_free(fib6_node_kmem, fn);
171 }
172 
173 static void node_free(struct net *net, struct fib6_node *fn)
174 {
175         call_rcu(&fn->rcu, node_free_rcu);
176         net->ipv6.rt6_stats->fib_nodes--;
177 }
178 
179 void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
180 {
181         int cpu;
182 
183         if (!non_pcpu_rt->rt6i_pcpu)
184                 return;
185 
186         for_each_possible_cpu(cpu) {
187                 struct rt6_info **ppcpu_rt;
188                 struct rt6_info *pcpu_rt;
189 
190                 ppcpu_rt = per_cpu_ptr(non_pcpu_rt->rt6i_pcpu, cpu);
191                 pcpu_rt = *ppcpu_rt;
192                 if (pcpu_rt) {
193                         dst_dev_put(&pcpu_rt->dst);
194                         dst_release(&pcpu_rt->dst);
195                         *ppcpu_rt = NULL;
196                 }
197         }
198 }
199 EXPORT_SYMBOL_GPL(rt6_free_pcpu);
200 
201 static void fib6_free_table(struct fib6_table *table)
202 {
203         inetpeer_invalidate_tree(&table->tb6_peers);
204         kfree(table);
205 }
206 
207 static void fib6_link_table(struct net *net, struct fib6_table *tb)
208 {
209         unsigned int h;
210 
211         /*
212          * Initialize table lock at a single place to give lockdep a key,
213          * tables aren't visible prior to being linked to the list.
214          */
215         spin_lock_init(&tb->tb6_lock);
216         h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
217 
218         /*
219          * No protection necessary, this is the only list mutatation
220          * operation, tables never disappear once they exist.
221          */
222         hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
223 }
224 
225 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
226 
227 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
228 {
229         struct fib6_table *table;
230 
231         table = kzalloc(sizeof(*table), GFP_ATOMIC);
232         if (table) {
233                 table->tb6_id = id;
234                 rcu_assign_pointer(table->tb6_root.leaf,
235                                    net->ipv6.ip6_null_entry);
236                 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
237                 inet_peer_base_init(&table->tb6_peers);
238         }
239 
240         return table;
241 }
242 
243 struct fib6_table *fib6_new_table(struct net *net, u32 id)
244 {
245         struct fib6_table *tb;
246 
247         if (id == 0)
248                 id = RT6_TABLE_MAIN;
249         tb = fib6_get_table(net, id);
250         if (tb)
251                 return tb;
252 
253         tb = fib6_alloc_table(net, id);
254         if (tb)
255                 fib6_link_table(net, tb);
256 
257         return tb;
258 }
259 EXPORT_SYMBOL_GPL(fib6_new_table);
260 
261 struct fib6_table *fib6_get_table(struct net *net, u32 id)
262 {
263         struct fib6_table *tb;
264         struct hlist_head *head;
265         unsigned int h;
266 
267         if (id == 0)
268                 id = RT6_TABLE_MAIN;
269         h = id & (FIB6_TABLE_HASHSZ - 1);
270         rcu_read_lock();
271         head = &net->ipv6.fib_table_hash[h];
272         hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
273                 if (tb->tb6_id == id) {
274                         rcu_read_unlock();
275                         return tb;
276                 }
277         }
278         rcu_read_unlock();
279 
280         return NULL;
281 }
282 EXPORT_SYMBOL_GPL(fib6_get_table);
283 
284 static void __net_init fib6_tables_init(struct net *net)
285 {
286         fib6_link_table(net, net->ipv6.fib6_main_tbl);
287         fib6_link_table(net, net->ipv6.fib6_local_tbl);
288 }
289 #else
290 
291 struct fib6_table *fib6_new_table(struct net *net, u32 id)
292 {
293         return fib6_get_table(net, id);
294 }
295 
296 struct fib6_table *fib6_get_table(struct net *net, u32 id)
297 {
298           return net->ipv6.fib6_main_tbl;
299 }
300 
301 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
302                                    const struct sk_buff *skb,
303                                    int flags, pol_lookup_t lookup)
304 {
305         struct rt6_info *rt;
306 
307         rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
308         if (rt->dst.error == -EAGAIN) {
309                 ip6_rt_put(rt);
310                 rt = net->ipv6.ip6_null_entry;
311                 dst_hold(&rt->dst);
312         }
313 
314         return &rt->dst;
315 }
316 
317 static void __net_init fib6_tables_init(struct net *net)
318 {
319         fib6_link_table(net, net->ipv6.fib6_main_tbl);
320 }
321 
322 #endif
323 
324 unsigned int fib6_tables_seq_read(struct net *net)
325 {
326         unsigned int h, fib_seq = 0;
327 
328         rcu_read_lock();
329         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
330                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
331                 struct fib6_table *tb;
332 
333                 hlist_for_each_entry_rcu(tb, head, tb6_hlist)
334                         fib_seq += tb->fib_seq;
335         }
336         rcu_read_unlock();
337 
338         return fib_seq;
339 }
340 
341 static int call_fib6_entry_notifier(struct notifier_block *nb, struct net *net,
342                                     enum fib_event_type event_type,
343                                     struct rt6_info *rt)
344 {
345         struct fib6_entry_notifier_info info = {
346                 .rt = rt,
347         };
348 
349         return call_fib6_notifier(nb, net, event_type, &info.info);
350 }
351 
352 static int call_fib6_entry_notifiers(struct net *net,
353                                      enum fib_event_type event_type,
354                                      struct rt6_info *rt,
355                                      struct netlink_ext_ack *extack)
356 {
357         struct fib6_entry_notifier_info info = {
358                 .info.extack = extack,
359                 .rt = rt,
360         };
361 
362         rt->rt6i_table->fib_seq++;
363         return call_fib6_notifiers(net, event_type, &info.info);
364 }
365 
366 struct fib6_dump_arg {
367         struct net *net;
368         struct notifier_block *nb;
369 };
370 
371 static void fib6_rt_dump(struct rt6_info *rt, struct fib6_dump_arg *arg)
372 {
373         if (rt == arg->net->ipv6.ip6_null_entry)
374                 return;
375         call_fib6_entry_notifier(arg->nb, arg->net, FIB_EVENT_ENTRY_ADD, rt);
376 }
377 
378 static int fib6_node_dump(struct fib6_walker *w)
379 {
380         struct rt6_info *rt;
381 
382         for_each_fib6_walker_rt(w)
383                 fib6_rt_dump(rt, w->args);
384         w->leaf = NULL;
385         return 0;
386 }
387 
388 static void fib6_table_dump(struct net *net, struct fib6_table *tb,
389                             struct fib6_walker *w)
390 {
391         w->root = &tb->tb6_root;
392         spin_lock_bh(&tb->tb6_lock);
393         fib6_walk(net, w);
394         spin_unlock_bh(&tb->tb6_lock);
395 }
396 
397 /* Called with rcu_read_lock() */
398 int fib6_tables_dump(struct net *net, struct notifier_block *nb)
399 {
400         struct fib6_dump_arg arg;
401         struct fib6_walker *w;
402         unsigned int h;
403 
404         w = kzalloc(sizeof(*w), GFP_ATOMIC);
405         if (!w)
406                 return -ENOMEM;
407 
408         w->func = fib6_node_dump;
409         arg.net = net;
410         arg.nb = nb;
411         w->args = &arg;
412 
413         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
414                 struct hlist_head *head = &net->ipv6.fib_table_hash[h];
415                 struct fib6_table *tb;
416 
417                 hlist_for_each_entry_rcu(tb, head, tb6_hlist)
418                         fib6_table_dump(net, tb, w);
419         }
420 
421         kfree(w);
422 
423         return 0;
424 }
425 
426 static int fib6_dump_node(struct fib6_walker *w)
427 {
428         int res;
429         struct rt6_info *rt;
430 
431         for_each_fib6_walker_rt(w) {
432                 res = rt6_dump_route(rt, w->args);
433                 if (res < 0) {
434                         /* Frame is full, suspend walking */
435                         w->leaf = rt;
436                         return 1;
437                 }
438 
439                 /* Multipath routes are dumped in one route with the
440                  * RTA_MULTIPATH attribute. Jump 'rt' to point to the
441                  * last sibling of this route (no need to dump the
442                  * sibling routes again)
443                  */
444                 if (rt->rt6i_nsiblings)
445                         rt = list_last_entry(&rt->rt6i_siblings,
446                                              struct rt6_info,
447                                              rt6i_siblings);
448         }
449         w->leaf = NULL;
450         return 0;
451 }
452 
453 static void fib6_dump_end(struct netlink_callback *cb)
454 {
455         struct net *net = sock_net(cb->skb->sk);
456         struct fib6_walker *w = (void *)cb->args[2];
457 
458         if (w) {
459                 if (cb->args[4]) {
460                         cb->args[4] = 0;
461                         fib6_walker_unlink(net, w);
462                 }
463                 cb->args[2] = 0;
464                 kfree(w);
465         }
466         cb->done = (void *)cb->args[3];
467         cb->args[1] = 3;
468 }
469 
470 static int fib6_dump_done(struct netlink_callback *cb)
471 {
472         fib6_dump_end(cb);
473         return cb->done ? cb->done(cb) : 0;
474 }
475 
476 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
477                            struct netlink_callback *cb)
478 {
479         struct net *net = sock_net(skb->sk);
480         struct fib6_walker *w;
481         int res;
482 
483         w = (void *)cb->args[2];
484         w->root = &table->tb6_root;
485 
486         if (cb->args[4] == 0) {
487                 w->count = 0;
488                 w->skip = 0;
489 
490                 spin_lock_bh(&table->tb6_lock);
491                 res = fib6_walk(net, w);
492                 spin_unlock_bh(&table->tb6_lock);
493                 if (res > 0) {
494                         cb->args[4] = 1;
495                         cb->args[5] = w->root->fn_sernum;
496                 }
497         } else {
498                 if (cb->args[5] != w->root->fn_sernum) {
499                         /* Begin at the root if the tree changed */
500                         cb->args[5] = w->root->fn_sernum;
501                         w->state = FWS_INIT;
502                         w->node = w->root;
503                         w->skip = w->count;
504                 } else
505                         w->skip = 0;
506 
507                 spin_lock_bh(&table->tb6_lock);
508                 res = fib6_walk_continue(w);
509                 spin_unlock_bh(&table->tb6_lock);
510                 if (res <= 0) {
511                         fib6_walker_unlink(net, w);
512                         cb->args[4] = 0;
513                 }
514         }
515 
516         return res;
517 }
518 
519 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
520 {
521         struct net *net = sock_net(skb->sk);
522         unsigned int h, s_h;
523         unsigned int e = 0, s_e;
524         struct rt6_rtnl_dump_arg arg;
525         struct fib6_walker *w;
526         struct fib6_table *tb;
527         struct hlist_head *head;
528         int res = 0;
529 
530         s_h = cb->args[0];
531         s_e = cb->args[1];
532 
533         w = (void *)cb->args[2];
534         if (!w) {
535                 /* New dump:
536                  *
537                  * 1. hook callback destructor.
538                  */
539                 cb->args[3] = (long)cb->done;
540                 cb->done = fib6_dump_done;
541 
542                 /*
543                  * 2. allocate and initialize walker.
544                  */
545                 w = kzalloc(sizeof(*w), GFP_ATOMIC);
546                 if (!w)
547                         return -ENOMEM;
548                 w->func = fib6_dump_node;
549                 cb->args[2] = (long)w;
550         }
551 
552         arg.skb = skb;
553         arg.cb = cb;
554         arg.net = net;
555         w->args = &arg;
556 
557         rcu_read_lock();
558         for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
559                 e = 0;
560                 head = &net->ipv6.fib_table_hash[h];
561                 hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
562                         if (e < s_e)
563                                 goto next;
564                         res = fib6_dump_table(tb, skb, cb);
565                         if (res != 0)
566                                 goto out;
567 next:
568                         e++;
569                 }
570         }
571 out:
572         rcu_read_unlock();
573         cb->args[1] = e;
574         cb->args[0] = h;
575 
576         res = res < 0 ? res : skb->len;
577         if (res <= 0)
578                 fib6_dump_end(cb);
579         return res;
580 }
581 
582 /*
583  *      Routing Table
584  *
585  *      return the appropriate node for a routing tree "add" operation
586  *      by either creating and inserting or by returning an existing
587  *      node.
588  */
589 
590 static struct fib6_node *fib6_add_1(struct net *net,
591                                     struct fib6_table *table,
592                                     struct fib6_node *root,
593                                     struct in6_addr *addr, int plen,
594                                     int offset, int allow_create,
595                                     int replace_required,
596                                     struct netlink_ext_ack *extack)
597 {
598         struct fib6_node *fn, *in, *ln;
599         struct fib6_node *pn = NULL;
600         struct rt6key *key;
601         int     bit;
602         __be32  dir = 0;
603 
604         RT6_TRACE("fib6_add_1\n");
605 
606         /* insert node in tree */
607 
608         fn = root;
609 
610         do {
611                 struct rt6_info *leaf = rcu_dereference_protected(fn->leaf,
612                                             lockdep_is_held(&table->tb6_lock));
613                 key = (struct rt6key *)((u8 *)leaf + offset);
614 
615                 /*
616                  *      Prefix match
617                  */
618                 if (plen < fn->fn_bit ||
619                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
620                         if (!allow_create) {
621                                 if (replace_required) {
622                                         NL_SET_ERR_MSG(extack,
623                                                        "Can not replace route - no match found");
624                                         pr_warn("Can't replace route, no match found\n");
625                                         return ERR_PTR(-ENOENT);
626                                 }
627                                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
628                         }
629                         goto insert_above;
630                 }
631 
632                 /*
633                  *      Exact match ?
634                  */
635 
636                 if (plen == fn->fn_bit) {
637                         /* clean up an intermediate node */
638                         if (!(fn->fn_flags & RTN_RTINFO)) {
639                                 RCU_INIT_POINTER(fn->leaf, NULL);
640                                 rt6_release(leaf);
641                         /* remove null_entry in the root node */
642                         } else if (fn->fn_flags & RTN_TL_ROOT &&
643                                    rcu_access_pointer(fn->leaf) ==
644                                    net->ipv6.ip6_null_entry) {
645                                 RCU_INIT_POINTER(fn->leaf, NULL);
646                         }
647 
648                         return fn;
649                 }
650 
651                 /*
652                  *      We have more bits to go
653                  */
654 
655                 /* Try to walk down on tree. */
656                 dir = addr_bit_set(addr, fn->fn_bit);
657                 pn = fn;
658                 fn = dir ?
659                      rcu_dereference_protected(fn->right,
660                                         lockdep_is_held(&table->tb6_lock)) :
661                      rcu_dereference_protected(fn->left,
662                                         lockdep_is_held(&table->tb6_lock));
663         } while (fn);
664 
665         if (!allow_create) {
666                 /* We should not create new node because
667                  * NLM_F_REPLACE was specified without NLM_F_CREATE
668                  * I assume it is safe to require NLM_F_CREATE when
669                  * REPLACE flag is used! Later we may want to remove the
670                  * check for replace_required, because according
671                  * to netlink specification, NLM_F_CREATE
672                  * MUST be specified if new route is created.
673                  * That would keep IPv6 consistent with IPv4
674                  */
675                 if (replace_required) {
676                         NL_SET_ERR_MSG(extack,
677                                        "Can not replace route - no match found");
678                         pr_warn("Can't replace route, no match found\n");
679                         return ERR_PTR(-ENOENT);
680                 }
681                 pr_warn("NLM_F_CREATE should be set when creating new route\n");
682         }
683         /*
684          *      We walked to the bottom of tree.
685          *      Create new leaf node without children.
686          */
687 
688         ln = node_alloc(net);
689 
690         if (!ln)
691                 return ERR_PTR(-ENOMEM);
692         ln->fn_bit = plen;
693         RCU_INIT_POINTER(ln->parent, pn);
694 
695         if (dir)
696                 rcu_assign_pointer(pn->right, ln);
697         else
698                 rcu_assign_pointer(pn->left, ln);
699 
700         return ln;
701 
702 
703 insert_above:
704         /*
705          * split since we don't have a common prefix anymore or
706          * we have a less significant route.
707          * we've to insert an intermediate node on the list
708          * this new node will point to the one we need to create
709          * and the current
710          */
711 
712         pn = rcu_dereference_protected(fn->parent,
713                                        lockdep_is_held(&table->tb6_lock));
714 
715         /* find 1st bit in difference between the 2 addrs.
716 
717            See comment in __ipv6_addr_diff: bit may be an invalid value,
718            but if it is >= plen, the value is ignored in any case.
719          */
720 
721         bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
722 
723         /*
724          *              (intermediate)[in]
725          *                /        \
726          *      (new leaf node)[ln] (old node)[fn]
727          */
728         if (plen > bit) {
729                 in = node_alloc(net);
730                 ln = node_alloc(net);
731 
732                 if (!in || !ln) {
733                         if (in)
734                                 node_free_immediate(net, in);
735                         if (ln)
736                                 node_free_immediate(net, ln);
737                         return ERR_PTR(-ENOMEM);
738                 }
739 
740                 /*
741                  * new intermediate node.
742                  * RTN_RTINFO will
743                  * be off since that an address that chooses one of
744                  * the branches would not match less specific routes
745                  * in the other branch
746                  */
747 
748                 in->fn_bit = bit;
749 
750                 RCU_INIT_POINTER(in->parent, pn);
751                 in->leaf = fn->leaf;
752                 atomic_inc(&rcu_dereference_protected(in->leaf,
753                                 lockdep_is_held(&table->tb6_lock))->rt6i_ref);
754 
755                 /* update parent pointer */
756                 if (dir)
757                         rcu_assign_pointer(pn->right, in);
758                 else
759                         rcu_assign_pointer(pn->left, in);
760 
761                 ln->fn_bit = plen;
762 
763                 RCU_INIT_POINTER(ln->parent, in);
764                 rcu_assign_pointer(fn->parent, in);
765 
766                 if (addr_bit_set(addr, bit)) {
767                         rcu_assign_pointer(in->right, ln);
768                         rcu_assign_pointer(in->left, fn);
769                 } else {
770                         rcu_assign_pointer(in->left, ln);
771                         rcu_assign_pointer(in->right, fn);
772                 }
773         } else { /* plen <= bit */
774 
775                 /*
776                  *              (new leaf node)[ln]
777                  *                /        \
778                  *           (old node)[fn] NULL
779                  */
780 
781                 ln = node_alloc(net);
782 
783                 if (!ln)
784                         return ERR_PTR(-ENOMEM);
785 
786                 ln->fn_bit = plen;
787 
788                 RCU_INIT_POINTER(ln->parent, pn);
789 
790                 if (addr_bit_set(&key->addr, plen))
791                         RCU_INIT_POINTER(ln->right, fn);
792                 else
793                         RCU_INIT_POINTER(ln->left, fn);
794 
795                 rcu_assign_pointer(fn->parent, ln);
796 
797                 if (dir)
798                         rcu_assign_pointer(pn->right, ln);
799                 else
800                         rcu_assign_pointer(pn->left, ln);
801         }
802         return ln;
803 }
804 
805 static void fib6_copy_metrics(u32 *mp, const struct mx6_config *mxc)
806 {
807         int i;
808 
809         for (i = 0; i < RTAX_MAX; i++) {
810                 if (test_bit(i, mxc->mx_valid))
811                         mp[i] = mxc->mx[i];
812         }
813 }
814 
815 static int fib6_commit_metrics(struct dst_entry *dst, struct mx6_config *mxc)
816 {
817         if (!mxc->mx)
818                 return 0;
819 
820         if (dst->flags & DST_HOST) {
821                 u32 *mp = dst_metrics_write_ptr(dst);
822 
823                 if (unlikely(!mp))
824                         return -ENOMEM;
825 
826                 fib6_copy_metrics(mp, mxc);
827         } else {
828                 dst_init_metrics(dst, mxc->mx, false);
829 
830                 /* We've stolen mx now. */
831                 mxc->mx = NULL;
832         }
833 
834         return 0;
835 }
836 
837 static void fib6_purge_rt(struct rt6_info *rt, struct fib6_node *fn,
838                           struct net *net)
839 {
840         struct fib6_table *table = rt->rt6i_table;
841 
842         if (atomic_read(&rt->rt6i_ref) != 1) {
843                 /* This route is used as dummy address holder in some split
844                  * nodes. It is not leaked, but it still holds other resources,
845                  * which must be released in time. So, scan ascendant nodes
846                  * and replace dummy references to this route with references
847                  * to still alive ones.
848                  */
849                 while (fn) {
850                         struct rt6_info *leaf = rcu_dereference_protected(fn->leaf,
851                                             lockdep_is_held(&table->tb6_lock));
852                         struct rt6_info *new_leaf;
853                         if (!(fn->fn_flags & RTN_RTINFO) && leaf == rt) {
854                                 new_leaf = fib6_find_prefix(net, table, fn);
855                                 atomic_inc(&new_leaf->rt6i_ref);
856                                 rcu_assign_pointer(fn->leaf, new_leaf);
857                                 rt6_release(rt);
858                         }
859                         fn = rcu_dereference_protected(fn->parent,
860                                     lockdep_is_held(&table->tb6_lock));
861                 }
862         }
863 }
864 
865 /*
866  *      Insert routing information in a node.
867  */
868 
869 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
870                             struct nl_info *info, struct mx6_config *mxc,
871                             struct netlink_ext_ack *extack)
872 {
873         struct rt6_info *leaf = rcu_dereference_protected(fn->leaf,
874                                     lockdep_is_held(&rt->rt6i_table->tb6_lock));
875         struct rt6_info *iter = NULL;
876         struct rt6_info __rcu **ins;
877         struct rt6_info __rcu **fallback_ins = NULL;
878         int replace = (info->nlh &&
879                        (info->nlh->nlmsg_flags & NLM_F_REPLACE));
880         int add = (!info->nlh ||
881                    (info->nlh->nlmsg_flags & NLM_F_CREATE));
882         int found = 0;
883         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
884         u16 nlflags = NLM_F_EXCL;
885         int err;
886 
887         if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))
888                 nlflags |= NLM_F_APPEND;
889 
890         ins = &fn->leaf;
891 
892         for (iter = leaf; iter;
893              iter = rcu_dereference_protected(iter->rt6_next,
894                                 lockdep_is_held(&rt->rt6i_table->tb6_lock))) {
895                 /*
896                  *      Search for duplicates
897                  */
898 
899                 if (iter->rt6i_metric == rt->rt6i_metric) {
900                         /*
901                          *      Same priority level
902                          */
903                         if (info->nlh &&
904                             (info->nlh->nlmsg_flags & NLM_F_EXCL))
905                                 return -EEXIST;
906 
907                         nlflags &= ~NLM_F_EXCL;
908                         if (replace) {
909                                 if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
910                                         found++;
911                                         break;
912                                 }
913                                 if (rt_can_ecmp)
914                                         fallback_ins = fallback_ins ?: ins;
915                                 goto next_iter;
916                         }
917 
918                         if (rt6_duplicate_nexthop(iter, rt)) {
919                                 if (rt->rt6i_nsiblings)
920                                         rt->rt6i_nsiblings = 0;
921                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
922                                         return -EEXIST;
923                                 if (!(rt->rt6i_flags & RTF_EXPIRES))
924                                         rt6_clean_expires(iter);
925                                 else
926                                         rt6_set_expires(iter, rt->dst.expires);
927                                 iter->rt6i_pmtu = rt->rt6i_pmtu;
928                                 return -EEXIST;
929                         }
930                         /* If we have the same destination and the same metric,
931                          * but not the same gateway, then the route we try to
932                          * add is sibling to this route, increment our counter
933                          * of siblings, and later we will add our route to the
934                          * list.
935                          * Only static routes (which don't have flag
936                          * RTF_EXPIRES) are used for ECMPv6.
937                          *
938                          * To avoid long list, we only had siblings if the
939                          * route have a gateway.
940                          */
941                         if (rt_can_ecmp &&
942                             rt6_qualify_for_ecmp(iter))
943                                 rt->rt6i_nsiblings++;
944                 }
945 
946                 if (iter->rt6i_metric > rt->rt6i_metric)
947                         break;
948 
949 next_iter:
950                 ins = &iter->rt6_next;
951         }
952 
953         if (fallback_ins && !found) {
954                 /* No ECMP-able route found, replace first non-ECMP one */
955                 ins = fallback_ins;
956                 iter = rcu_dereference_protected(*ins,
957                                     lockdep_is_held(&rt->rt6i_table->tb6_lock));
958                 found++;
959         }
960 
961         /* Reset round-robin state, if necessary */
962         if (ins == &fn->leaf)
963                 fn->rr_ptr = NULL;
964 
965         /* Link this route to others same route. */
966         if (rt->rt6i_nsiblings) {
967                 unsigned int rt6i_nsiblings;
968                 struct rt6_info *sibling, *temp_sibling;
969 
970                 /* Find the first route that have the same metric */
971                 sibling = leaf;
972                 while (sibling) {
973                         if (sibling->rt6i_metric == rt->rt6i_metric &&
974                             rt6_qualify_for_ecmp(sibling)) {
975                                 list_add_tail(&rt->rt6i_siblings,
976                                               &sibling->rt6i_siblings);
977                                 break;
978                         }
979                         sibling = rcu_dereference_protected(sibling->rt6_next,
980                                     lockdep_is_held(&rt->rt6i_table->tb6_lock));
981                 }
982                 /* For each sibling in the list, increment the counter of
983                  * siblings. BUG() if counters does not match, list of siblings
984                  * is broken!
985                  */
986                 rt6i_nsiblings = 0;
987                 list_for_each_entry_safe(sibling, temp_sibling,
988                                          &rt->rt6i_siblings, rt6i_siblings) {
989                         sibling->rt6i_nsiblings++;
990                         BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
991                         rt6i_nsiblings++;
992                 }
993                 BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
994                 rt6_multipath_rebalance(temp_sibling);
995         }
996 
997         /*
998          *      insert node
999          */
1000         if (!replace) {
1001                 if (!add)
1002                         pr_warn("NLM_F_CREATE should be set when creating new route\n");
1003 
1004 add:
1005                 nlflags |= NLM_F_CREATE;
1006                 err = fib6_commit_metrics(&rt->dst, mxc);
1007                 if (err)
1008                         return err;
1009 
1010                 err = call_fib6_entry_notifiers(info->nl_net,
1011                                                 FIB_EVENT_ENTRY_ADD,
1012                                                 rt, extack);
1013                 if (err)
1014                         return err;
1015 
1016                 rcu_assign_pointer(rt->rt6_next, iter);
1017                 atomic_inc(&rt->rt6i_ref);
1018                 rcu_assign_pointer(rt->rt6i_node, fn);
1019                 rcu_assign_pointer(*ins, rt);
1020                 if (!info->skip_notify)
1021                         inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
1022                 info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
1023 
1024                 if (!(fn->fn_flags & RTN_RTINFO)) {
1025                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1026                         fn->fn_flags |= RTN_RTINFO;
1027                 }
1028 
1029         } else {
1030                 int nsiblings;
1031 
1032                 if (!found) {
1033                         if (add)
1034                                 goto add;
1035                         pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
1036                         return -ENOENT;
1037                 }
1038 
1039                 err = fib6_commit_metrics(&rt->dst, mxc);
1040                 if (err)
1041                         return err;
1042 
1043                 err = call_fib6_entry_notifiers(info->nl_net,
1044                                                 FIB_EVENT_ENTRY_REPLACE,
1045                                                 rt, extack);
1046                 if (err)
1047                         return err;
1048 
1049                 atomic_inc(&rt->rt6i_ref);
1050                 rcu_assign_pointer(rt->rt6i_node, fn);
1051                 rt->rt6_next = iter->rt6_next;
1052                 rcu_assign_pointer(*ins, rt);
1053                 if (!info->skip_notify)
1054                         inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
1055                 if (!(fn->fn_flags & RTN_RTINFO)) {
1056                         info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
1057                         fn->fn_flags |= RTN_RTINFO;
1058                 }
1059                 nsiblings = iter->rt6i_nsiblings;
1060                 iter->rt6i_node = NULL;
1061                 fib6_purge_rt(iter, fn, info->nl_net);
1062                 if (rcu_access_pointer(fn->rr_ptr) == iter)
1063                         fn->rr_ptr = NULL;
1064                 rt6_release(iter);
1065 
1066                 if (nsiblings) {
1067                         /* Replacing an ECMP route, remove all siblings */
1068                         ins = &rt->rt6_next;
1069                         iter = rcu_dereference_protected(*ins,
1070                                     lockdep_is_held(&rt->rt6i_table->tb6_lock));
1071                         while (iter) {
1072                                 if (iter->rt6i_metric > rt->rt6i_metric)
1073                                         break;
1074                                 if (rt6_qualify_for_ecmp(iter)) {
1075                                         *ins = iter->rt6_next;
1076                                         iter->rt6i_node = NULL;
1077                                         fib6_purge_rt(iter, fn, info->nl_net);
1078                                         if (rcu_access_pointer(fn->rr_ptr) == iter)
1079                                                 fn->rr_ptr = NULL;
1080                                         rt6_release(iter);
1081                                         nsiblings--;
1082                                         info->nl_net->ipv6.rt6_stats->fib_rt_entries--;
1083                                 } else {
1084                                         ins = &iter->rt6_next;
1085                                 }
1086                                 iter = rcu_dereference_protected(*ins,
1087                                         lockdep_is_held(&rt->rt6i_table->tb6_lock));
1088                         }
1089                         WARN_ON(nsiblings != 0);
1090                 }
1091         }
1092 
1093         return 0;
1094 }
1095 
1096 static void fib6_start_gc(struct net *net, struct rt6_info *rt)
1097 {
1098         if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
1099             (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
1100                 mod_timer(&net->ipv6.ip6_fib_timer,
1101                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1102 }
1103 
1104 void fib6_force_start_gc(struct net *net)
1105 {
1106         if (!timer_pending(&net->ipv6.ip6_fib_timer))
1107                 mod_timer(&net->ipv6.ip6_fib_timer,
1108                           jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
1109 }
1110 
1111 static void __fib6_update_sernum_upto_root(struct rt6_info *rt,
1112                                            int sernum)
1113 {
1114         struct fib6_node *fn = rcu_dereference_protected(rt->rt6i_node,
1115                                 lockdep_is_held(&rt->rt6i_table->tb6_lock));
1116 
1117         /* paired with smp_rmb() in rt6_get_cookie_safe() */
1118         smp_wmb();
1119         while (fn) {
1120                 fn->fn_sernum = sernum;
1121                 fn = rcu_dereference_protected(fn->parent,
1122                                 lockdep_is_held(&rt->rt6i_table->tb6_lock));
1123         }
1124 }
1125 
1126 void fib6_update_sernum_upto_root(struct net *net, struct rt6_info *rt)
1127 {
1128         __fib6_update_sernum_upto_root(rt, fib6_new_sernum(net));
1129 }
1130 
1131 /*
1132  *      Add routing information to the routing tree.
1133  *      <destination addr>/<source addr>
1134  *      with source addr info in sub-trees
1135  *      Need to own table->tb6_lock
1136  */
1137 
1138 int fib6_add(struct fib6_node *root, struct rt6_info *rt,
1139              struct nl_info *info, struct mx6_config *mxc,
1140              struct netlink_ext_ack *extack)
1141 {
1142         struct fib6_table *table = rt->rt6i_table;
1143         struct fib6_node *fn, *pn = NULL;
1144         int err = -ENOMEM;
1145         int allow_create = 1;
1146         int replace_required = 0;
1147         int sernum = fib6_new_sernum(info->nl_net);
1148 
1149         if (WARN_ON_ONCE(!atomic_read(&rt->dst.__refcnt)))
1150                 return -EINVAL;
1151         if (WARN_ON_ONCE(rt->rt6i_flags & RTF_CACHE))
1152                 return -EINVAL;
1153 
1154         if (info->nlh) {
1155                 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
1156                         allow_create = 0;
1157                 if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
1158                         replace_required = 1;
1159         }
1160         if (!allow_create && !replace_required)
1161                 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
1162 
1163         fn = fib6_add_1(info->nl_net, table, root,
1164                         &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
1165                         offsetof(struct rt6_info, rt6i_dst), allow_create,
1166                         replace_required, extack);
1167         if (IS_ERR(fn)) {
1168                 err = PTR_ERR(fn);
1169                 fn = NULL;
1170                 goto out;
1171         }
1172 
1173         pn = fn;
1174 
1175 #ifdef CONFIG_IPV6_SUBTREES
1176         if (rt->rt6i_src.plen) {
1177                 struct fib6_node *sn;
1178 
1179                 if (!rcu_access_pointer(fn->subtree)) {
1180                         struct fib6_node *sfn;
1181 
1182                         /*
1183                          * Create subtree.
1184                          *
1185                          *              fn[main tree]
1186                          *              |
1187                          *              sfn[subtree root]
1188                          *                 \
1189                          *                  sn[new leaf node]
1190                          */
1191 
1192                         /* Create subtree root node */
1193                         sfn = node_alloc(info->nl_net);
1194                         if (!sfn)
1195                                 goto failure;
1196 
1197                         atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
1198                         rcu_assign_pointer(sfn->leaf,
1199                                            info->nl_net->ipv6.ip6_null_entry);
1200                         sfn->fn_flags = RTN_ROOT;
1201 
1202                         /* Now add the first leaf node to new subtree */
1203 
1204                         sn = fib6_add_1(info->nl_net, table, sfn,
1205                                         &rt->rt6i_src.addr, rt->rt6i_src.plen,
1206                                         offsetof(struct rt6_info, rt6i_src),
1207                                         allow_create, replace_required, extack);
1208 
1209                         if (IS_ERR(sn)) {
1210                                 /* If it is failed, discard just allocated
1211                                    root, and then (in failure) stale node
1212                                    in main tree.
1213                                  */
1214                                 node_free_immediate(info->nl_net, sfn);
1215                                 err = PTR_ERR(sn);
1216                                 goto failure;
1217                         }
1218 
1219                         /* Now link new subtree to main tree */
1220                         rcu_assign_pointer(sfn->parent, fn);
1221                         rcu_assign_pointer(fn->subtree, sfn);
1222                 } else {
1223                         sn = fib6_add_1(info->nl_net, table, FIB6_SUBTREE(fn),
1224                                         &rt->rt6i_src.addr, rt->rt6i_src.plen,
1225                                         offsetof(struct rt6_info, rt6i_src),
1226                                         allow_create, replace_required, extack);
1227 
1228                         if (IS_ERR(sn)) {
1229                                 err = PTR_ERR(sn);
1230                                 goto failure;
1231                         }
1232                 }
1233 
1234                 if (!rcu_access_pointer(fn->leaf)) {
1235                         if (fn->fn_flags & RTN_TL_ROOT) {
1236                                 /* put back null_entry for root node */
1237                                 rcu_assign_pointer(fn->leaf,
1238                                             info->nl_net->ipv6.ip6_null_entry);
1239                         } else {
1240                                 atomic_inc(&rt->rt6i_ref);
1241                                 rcu_assign_pointer(fn->leaf, rt);
1242                         }
1243                 }
1244                 fn = sn;
1245         }
1246 #endif
1247 
1248         err = fib6_add_rt2node(fn, rt, info, mxc, extack);
1249         if (!err) {
1250                 __fib6_update_sernum_upto_root(rt, sernum);
1251                 fib6_start_gc(info->nl_net, rt);
1252         }
1253 
1254 out:
1255         if (err) {
1256 #ifdef CONFIG_IPV6_SUBTREES
1257                 /*
1258                  * If fib6_add_1 has cleared the old leaf pointer in the
1259                  * super-tree leaf node we have to find a new one for it.
1260                  */
1261                 if (pn != fn) {
1262                         struct rt6_info *pn_leaf =
1263                                 rcu_dereference_protected(pn->leaf,
1264                                     lockdep_is_held(&table->tb6_lock));
1265                         if (pn_leaf == rt) {
1266                                 pn_leaf = NULL;
1267                                 RCU_INIT_POINTER(pn->leaf, NULL);
1268                                 atomic_dec(&rt->rt6i_ref);
1269                         }
1270                         if (!pn_leaf && !(pn->fn_flags & RTN_RTINFO)) {
1271                                 pn_leaf = fib6_find_prefix(info->nl_net, table,
1272                                                            pn);
1273 #if RT6_DEBUG >= 2
1274                                 if (!pn_leaf) {
1275                                         WARN_ON(!pn_leaf);
1276                                         pn_leaf =
1277                                             info->nl_net->ipv6.ip6_null_entry;
1278                                 }
1279 #endif
1280                                 atomic_inc(&pn_leaf->rt6i_ref);
1281                                 rcu_assign_pointer(pn->leaf, pn_leaf);
1282                         }
1283                 }
1284 #endif
1285                 goto failure;
1286         }
1287         return err;
1288 
1289 failure:
1290         /* fn->leaf could be NULL and fib6_repair_tree() needs to be called if:
1291          * 1. fn is an intermediate node and we failed to add the new
1292          * route to it in both subtree creation failure and fib6_add_rt2node()
1293          * failure case.
1294          * 2. fn is the root node in the table and we fail to add the first
1295          * default route to it.
1296          */
1297         if (fn &&
1298             (!(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)) ||
1299              (fn->fn_flags & RTN_TL_ROOT &&
1300               !rcu_access_pointer(fn->leaf))))
1301                 fib6_repair_tree(info->nl_net, table, fn);
1302         /* Always release dst as dst->__refcnt is guaranteed
1303          * to be taken before entering this function
1304          */
1305         dst_release_immediate(&rt->dst);
1306         return err;
1307 }
1308 
1309 /*
1310  *      Routing tree lookup
1311  *
1312  */
1313 
1314 struct lookup_args {
1315         int                     offset;         /* key offset on rt6_info       */
1316         const struct in6_addr   *addr;          /* search key                   */
1317 };
1318 
1319 static struct fib6_node *fib6_lookup_1(struct fib6_node *root,
1320                                        struct lookup_args *args)
1321 {
1322         struct fib6_node *fn;
1323         __be32 dir;
1324 
1325         if (unlikely(args->offset == 0))
1326                 return NULL;
1327 
1328         /*
1329          *      Descend on a tree
1330          */
1331 
1332         fn = root;
1333 
1334         for (;;) {
1335                 struct fib6_node *next;
1336 
1337                 dir = addr_bit_set(args->addr, fn->fn_bit);
1338 
1339                 next = dir ? rcu_dereference(fn->right) :
1340                              rcu_dereference(fn->left);
1341 
1342                 if (next) {
1343                         fn = next;
1344                         continue;
1345                 }
1346                 break;
1347         }
1348 
1349         while (fn) {
1350                 struct fib6_node *subtree = FIB6_SUBTREE(fn);
1351 
1352                 if (subtree || fn->fn_flags & RTN_RTINFO) {
1353                         struct rt6_info *leaf = rcu_dereference(fn->leaf);
1354                         struct rt6key *key;
1355 
1356                         if (!leaf)
1357                                 goto backtrack;
1358 
1359                         key = (struct rt6key *) ((u8 *)leaf + args->offset);
1360 
1361                         if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1362 #ifdef CONFIG_IPV6_SUBTREES
1363                                 if (subtree) {
1364                                         struct fib6_node *sfn;
1365                                         sfn = fib6_lookup_1(subtree, args + 1);
1366                                         if (!sfn)
1367                                                 goto backtrack;
1368                                         fn = sfn;
1369                                 }
1370 #endif
1371                                 if (fn->fn_flags & RTN_RTINFO)
1372                                         return fn;
1373                         }
1374                 }
1375 backtrack:
1376                 if (fn->fn_flags & RTN_ROOT)
1377                         break;
1378 
1379                 fn = rcu_dereference(fn->parent);
1380         }
1381 
1382         return NULL;
1383 }
1384 
1385 /* called with rcu_read_lock() held
1386  */
1387 struct fib6_node *fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
1388                               const struct in6_addr *saddr)
1389 {
1390         struct fib6_node *fn;
1391         struct lookup_args args[] = {
1392                 {
1393                         .offset = offsetof(struct rt6_info, rt6i_dst),
1394                         .addr = daddr,
1395                 },
1396 #ifdef CONFIG_IPV6_SUBTREES
1397                 {
1398                         .offset = offsetof(struct rt6_info, rt6i_src),
1399                         .addr = saddr,
1400                 },
1401 #endif
1402                 {
1403                         .offset = 0,    /* sentinel */
1404                 }
1405         };
1406 
1407         fn = fib6_lookup_1(root, daddr ? args : args + 1);
1408         if (!fn || fn->fn_flags & RTN_TL_ROOT)
1409                 fn = root;
1410 
1411         return fn;
1412 }
1413 
1414 /*
1415  *      Get node with specified destination prefix (and source prefix,
1416  *      if subtrees are used)
1417  *      exact_match == true means we try to find fn with exact match of
1418  *      the passed in prefix addr
1419  *      exact_match == false means we try to find fn with longest prefix
1420  *      match of the passed in prefix addr. This is useful for finding fn
1421  *      for cached route as it will be stored in the exception table under
1422  *      the node with longest prefix length.
1423  */
1424 
1425 
1426 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1427                                        const struct in6_addr *addr,
1428                                        int plen, int offset,
1429                                        bool exact_match)
1430 {
1431         struct fib6_node *fn, *prev = NULL;
1432 
1433         for (fn = root; fn ; ) {
1434                 struct rt6_info *leaf = rcu_dereference(fn->leaf);
1435                 struct rt6key *key;
1436 
1437                 /* This node is being deleted */
1438                 if (!leaf) {
1439                         if (plen <= fn->fn_bit)
1440                                 goto out;
1441                         else
1442                                 goto next;
1443                 }
1444 
1445                 key = (struct rt6key *)((u8 *)leaf + offset);
1446 
1447                 /*
1448                  *      Prefix match
1449                  */
1450                 if (plen < fn->fn_bit ||
1451                     !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1452                         goto out;
1453 
1454                 if (plen == fn->fn_bit)
1455                         return fn;
1456 
1457                 prev = fn;
1458 
1459 next:
1460                 /*
1461                  *      We have more bits to go
1462                  */
1463                 if (addr_bit_set(addr, fn->fn_bit))
1464                         fn = rcu_dereference(fn->right);
1465                 else
1466                         fn = rcu_dereference(fn->left);
1467         }
1468 out:
1469         if (exact_match)
1470                 return NULL;
1471         else
1472                 return prev;
1473 }
1474 
1475 struct fib6_node *fib6_locate(struct fib6_node *root,
1476                               const struct in6_addr *daddr, int dst_len,
1477                               const struct in6_addr *saddr, int src_len,
1478                               bool exact_match)
1479 {
1480         struct fib6_node *fn;
1481 
1482         fn = fib6_locate_1(root, daddr, dst_len,
1483                            offsetof(struct rt6_info, rt6i_dst),
1484                            exact_match);
1485 
1486 #ifdef CONFIG_IPV6_SUBTREES
1487         if (src_len) {
1488                 WARN_ON(saddr == NULL);
1489                 if (fn) {
1490                         struct fib6_node *subtree = FIB6_SUBTREE(fn);
1491 
1492                         if (subtree) {
1493                                 fn = fib6_locate_1(subtree, saddr, src_len,
1494                                            offsetof(struct rt6_info, rt6i_src),
1495                                            exact_match);
1496                         }
1497                 }
1498         }
1499 #endif
1500 
1501         if (fn && fn->fn_flags & RTN_RTINFO)
1502                 return fn;
1503 
1504         return NULL;
1505 }
1506 
1507 
1508 /*
1509  *      Deletion
1510  *
1511  */
1512 
1513 static struct rt6_info *fib6_find_prefix(struct net *net,
1514                                          struct fib6_table *table,
1515                                          struct fib6_node *fn)
1516 {
1517         struct fib6_node *child_left, *child_right;
1518 
1519         if (fn->fn_flags & RTN_ROOT)
1520                 return net->ipv6.ip6_null_entry;
1521 
1522         while (fn) {
1523                 child_left = rcu_dereference_protected(fn->left,
1524                                     lockdep_is_held(&table->tb6_lock));
1525                 child_right = rcu_dereference_protected(fn->right,
1526                                     lockdep_is_held(&table->tb6_lock));
1527                 if (child_left)
1528                         return rcu_dereference_protected(child_left->leaf,
1529                                         lockdep_is_held(&table->tb6_lock));
1530                 if (child_right)
1531                         return rcu_dereference_protected(child_right->leaf,
1532                                         lockdep_is_held(&table->tb6_lock));
1533 
1534                 fn = FIB6_SUBTREE(fn);
1535         }
1536         return NULL;
1537 }
1538 
1539 /*
1540  *      Called to trim the tree of intermediate nodes when possible. "fn"
1541  *      is the node we want to try and remove.
1542  *      Need to own table->tb6_lock
1543  */
1544 
1545 static struct fib6_node *fib6_repair_tree(struct net *net,
1546                                           struct fib6_table *table,
1547                                           struct fib6_node *fn)
1548 {
1549         int children;
1550         int nstate;
1551         struct fib6_node *child;
1552         struct fib6_walker *w;
1553         int iter = 0;
1554 
1555         /* Set fn->leaf to null_entry for root node. */
1556         if (fn->fn_flags & RTN_TL_ROOT) {
1557                 rcu_assign_pointer(fn->leaf, net->ipv6.ip6_null_entry);
1558                 return fn;
1559         }
1560 
1561         for (;;) {
1562                 struct fib6_node *fn_r = rcu_dereference_protected(fn->right,
1563                                             lockdep_is_held(&table->tb6_lock));
1564                 struct fib6_node *fn_l = rcu_dereference_protected(fn->left,
1565                                             lockdep_is_held(&table->tb6_lock));
1566                 struct fib6_node *pn = rcu_dereference_protected(fn->parent,
1567                                             lockdep_is_held(&table->tb6_lock));
1568                 struct fib6_node *pn_r = rcu_dereference_protected(pn->right,
1569                                             lockdep_is_held(&table->tb6_lock));
1570                 struct fib6_node *pn_l = rcu_dereference_protected(pn->left,
1571                                             lockdep_is_held(&table->tb6_lock));
1572                 struct rt6_info *fn_leaf = rcu_dereference_protected(fn->leaf,
1573                                             lockdep_is_held(&table->tb6_lock));
1574                 struct rt6_info *pn_leaf = rcu_dereference_protected(pn->leaf,
1575                                             lockdep_is_held(&table->tb6_lock));
1576                 struct rt6_info *new_fn_leaf;
1577 
1578                 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1579                 iter++;
1580 
1581                 WARN_ON(fn->fn_flags & RTN_RTINFO);
1582                 WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1583                 WARN_ON(fn_leaf);
1584 
1585                 children = 0;
1586                 child = NULL;
1587                 if (fn_r)
1588                         child = fn_r, children |= 1;
1589                 if (fn_l)
1590                         child = fn_l, children |= 2;
1591 
1592                 if (children == 3 || FIB6_SUBTREE(fn)
1593 #ifdef CONFIG_IPV6_SUBTREES
1594                     /* Subtree root (i.e. fn) may have one child */
1595                     || (children && fn->fn_flags & RTN_ROOT)
1596 #endif
1597                     ) {
1598                         new_fn_leaf = fib6_find_prefix(net, table, fn);
1599 #if RT6_DEBUG >= 2
1600                         if (!new_fn_leaf) {
1601                                 WARN_ON(!new_fn_leaf);
1602                                 new_fn_leaf = net->ipv6.ip6_null_entry;
1603                         }
1604 #endif
1605                         atomic_inc(&new_fn_leaf->rt6i_ref);
1606                         rcu_assign_pointer(fn->leaf, new_fn_leaf);
1607                         return pn;
1608                 }
1609 
1610 #ifdef CONFIG_IPV6_SUBTREES
1611                 if (FIB6_SUBTREE(pn) == fn) {
1612                         WARN_ON(!(fn->fn_flags & RTN_ROOT));
1613                         RCU_INIT_POINTER(pn->subtree, NULL);
1614                         nstate = FWS_L;
1615                 } else {
1616                         WARN_ON(fn->fn_flags & RTN_ROOT);
1617 #endif
1618                         if (pn_r == fn)
1619                                 rcu_assign_pointer(pn->right, child);
1620                         else if (pn_l == fn)
1621                                 rcu_assign_pointer(pn->left, child);
1622 #if RT6_DEBUG >= 2
1623                         else
1624                                 WARN_ON(1);
1625 #endif
1626                         if (child)
1627                                 rcu_assign_pointer(child->parent, pn);
1628                         nstate = FWS_R;
1629 #ifdef CONFIG_IPV6_SUBTREES
1630                 }
1631 #endif
1632 
1633                 read_lock(&net->ipv6.fib6_walker_lock);
1634                 FOR_WALKERS(net, w) {
1635                         if (!child) {
1636                                 if (w->node == fn) {
1637                                         RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1638                                         w->node = pn;
1639                                         w->state = nstate;
1640                                 }
1641                         } else {
1642                                 if (w->node == fn) {
1643                                         w->node = child;
1644                                         if (children&2) {
1645                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1646                                                 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1647                                         } else {
1648                                                 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1649                                                 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1650                                         }
1651                                 }
1652                         }
1653                 }
1654                 read_unlock(&net->ipv6.fib6_walker_lock);
1655 
1656                 node_free(net, fn);
1657                 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1658                         return pn;
1659 
1660                 RCU_INIT_POINTER(pn->leaf, NULL);
1661                 rt6_release(pn_leaf);
1662                 fn = pn;
1663         }
1664 }
1665 
1666 static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
1667                            struct rt6_info __rcu **rtp, struct nl_info *info)
1668 {
1669         struct fib6_walker *w;
1670         struct rt6_info *rt = rcu_dereference_protected(*rtp,
1671                                     lockdep_is_held(&table->tb6_lock));
1672         struct net *net = info->nl_net;
1673 
1674         RT6_TRACE("fib6_del_route\n");
1675 
1676         WARN_ON_ONCE(rt->rt6i_flags & RTF_CACHE);
1677 
1678         /* Unlink it */
1679         *rtp = rt->rt6_next;
1680         rt->rt6i_node = NULL;
1681         net->ipv6.rt6_stats->fib_rt_entries--;
1682         net->ipv6.rt6_stats->fib_discarded_routes++;
1683 
1684         /* Flush all cached dst in exception table */
1685         rt6_flush_exceptions(rt);
1686 
1687         /* Reset round-robin state, if necessary */
1688         if (rcu_access_pointer(fn->rr_ptr) == rt)
1689                 fn->rr_ptr = NULL;
1690 
1691         /* Remove this entry from other siblings */
1692         if (rt->rt6i_nsiblings) {
1693                 struct rt6_info *sibling, *next_sibling;
1694 
1695                 list_for_each_entry_safe(sibling, next_sibling,
1696                                          &rt->rt6i_siblings, rt6i_siblings)
1697                         sibling->rt6i_nsiblings--;
1698                 rt->rt6i_nsiblings = 0;
1699                 list_del_init(&rt->rt6i_siblings);
1700                 rt6_multipath_rebalance(next_sibling);
1701         }
1702 
1703         /* Adjust walkers */
1704         read_lock(&net->ipv6.fib6_walker_lock);
1705         FOR_WALKERS(net, w) {
1706                 if (w->state == FWS_C && w->leaf == rt) {
1707                         RT6_TRACE("walker %p adjusted by delroute\n", w);
1708                         w->leaf = rcu_dereference_protected(rt->rt6_next,
1709                                             lockdep_is_held(&table->tb6_lock));
1710                         if (!w->leaf)
1711                                 w->state = FWS_U;
1712                 }
1713         }
1714         read_unlock(&net->ipv6.fib6_walker_lock);
1715 
1716         /* If it was last route, call fib6_repair_tree() to:
1717          * 1. For root node, put back null_entry as how the table was created.
1718          * 2. For other nodes, expunge its radix tree node.
1719          */
1720         if (!rcu_access_pointer(fn->leaf)) {
1721                 if (!(fn->fn_flags & RTN_TL_ROOT)) {
1722                         fn->fn_flags &= ~RTN_RTINFO;
1723                         net->ipv6.rt6_stats->fib_route_nodes--;
1724                 }
1725                 fn = fib6_repair_tree(net, table, fn);
1726         }
1727 
1728         fib6_purge_rt(rt, fn, net);
1729 
1730         call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, rt, NULL);
1731         if (!info->skip_notify)
1732                 inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
1733         rt6_release(rt);
1734 }
1735 
1736 /* Need to own table->tb6_lock */
1737 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1738 {
1739         struct fib6_node *fn = rcu_dereference_protected(rt->rt6i_node,
1740                                     lockdep_is_held(&rt->rt6i_table->tb6_lock));
1741         struct fib6_table *table = rt->rt6i_table;
1742         struct net *net = info->nl_net;
1743         struct rt6_info __rcu **rtp;
1744         struct rt6_info __rcu **rtp_next;
1745 
1746 #if RT6_DEBUG >= 2
1747         if (rt->dst.obsolete > 0) {
1748                 WARN_ON(fn);
1749                 return -ENOENT;
1750         }
1751 #endif
1752         if (!fn || rt == net->ipv6.ip6_null_entry)
1753                 return -ENOENT;
1754 
1755         WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1756 
1757         /* remove cached dst from exception table */
1758         if (rt->rt6i_flags & RTF_CACHE)
1759                 return rt6_remove_exception_rt(rt);
1760 
1761         /*
1762          *      Walk the leaf entries looking for ourself
1763          */
1764 
1765         for (rtp = &fn->leaf; *rtp; rtp = rtp_next) {
1766                 struct rt6_info *cur = rcu_dereference_protected(*rtp,
1767                                         lockdep_is_held(&table->tb6_lock));
1768                 if (rt == cur) {
1769                         fib6_del_route(table, fn, rtp, info);
1770                         return 0;
1771                 }
1772                 rtp_next = &cur->rt6_next;
1773         }
1774         return -ENOENT;
1775 }
1776 
1777 /*
1778  *      Tree traversal function.
1779  *
1780  *      Certainly, it is not interrupt safe.
1781  *      However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1782  *      It means, that we can modify tree during walking
1783  *      and use this function for garbage collection, clone pruning,
1784  *      cleaning tree when a device goes down etc. etc.
1785  *
1786  *      It guarantees that every node will be traversed,
1787  *      and that it will be traversed only once.
1788  *
1789  *      Callback function w->func may return:
1790  *      0 -> continue walking.
1791  *      positive value -> walking is suspended (used by tree dumps,
1792  *      and probably by gc, if it will be split to several slices)
1793  *      negative value -> terminate walking.
1794  *
1795  *      The function itself returns:
1796  *      0   -> walk is complete.
1797  *      >0  -> walk is incomplete (i.e. suspended)
1798  *      <0  -> walk is terminated by an error.
1799  *
1800  *      This function is called with tb6_lock held.
1801  */
1802 
1803 static int fib6_walk_continue(struct fib6_walker *w)
1804 {
1805         struct fib6_node *fn, *pn, *left, *right;
1806 
1807         /* w->root should always be table->tb6_root */
1808         WARN_ON_ONCE(!(w->root->fn_flags & RTN_TL_ROOT));
1809 
1810         for (;;) {
1811                 fn = w->node;
1812                 if (!fn)
1813                         return 0;
1814 
1815                 switch (w->state) {
1816 #ifdef CONFIG_IPV6_SUBTREES
1817                 case FWS_S:
1818                         if (FIB6_SUBTREE(fn)) {
1819                                 w->node = FIB6_SUBTREE(fn);
1820                                 continue;
1821                         }
1822                         w->state = FWS_L;
1823 #endif
1824                         /* fall through */
1825                 case FWS_L:
1826                         left = rcu_dereference_protected(fn->left, 1);
1827                         if (left) {
1828                                 w->node = left;
1829                                 w->state = FWS_INIT;
1830                                 continue;
1831                         }
1832                         w->state = FWS_R;
1833                         /* fall through */
1834                 case FWS_R:
1835                         right = rcu_dereference_protected(fn->right, 1);
1836                         if (right) {
1837                                 w->node = right;
1838                                 w->state = FWS_INIT;
1839                                 continue;
1840                         }
1841                         w->state = FWS_C;
1842                         w->leaf = rcu_dereference_protected(fn->leaf, 1);
1843                         /* fall through */
1844                 case FWS_C:
1845                         if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1846                                 int err;
1847 
1848                                 if (w->skip) {
1849                                         w->skip--;
1850                                         goto skip;
1851                                 }
1852 
1853                                 err = w->func(w);
1854                                 if (err)
1855                                         return err;
1856 
1857                                 w->count++;
1858                                 continue;
1859                         }
1860 skip:
1861                         w->state = FWS_U;
1862                         /* fall through */
1863                 case FWS_U:
1864                         if (fn == w->root)
1865                                 return 0;
1866                         pn = rcu_dereference_protected(fn->parent, 1);
1867                         left = rcu_dereference_protected(pn->left, 1);
1868                         right = rcu_dereference_protected(pn->right, 1);
1869                         w->node = pn;
1870 #ifdef CONFIG_IPV6_SUBTREES
1871                         if (FIB6_SUBTREE(pn) == fn) {
1872                                 WARN_ON(!(fn->fn_flags & RTN_ROOT));
1873                                 w->state = FWS_L;
1874                                 continue;
1875                         }
1876 #endif
1877                         if (left == fn) {
1878                                 w->state = FWS_R;
1879                                 continue;
1880                         }
1881                         if (right == fn) {
1882                                 w->state = FWS_C;
1883                                 w->leaf = rcu_dereference_protected(w->node->leaf, 1);
1884                                 continue;
1885                         }
1886 #if RT6_DEBUG >= 2
1887                         WARN_ON(1);
1888 #endif
1889                 }
1890         }
1891 }
1892 
1893 static int fib6_walk(struct net *net, struct fib6_walker *w)
1894 {
1895         int res;
1896 
1897         w->state = FWS_INIT;
1898         w->node = w->root;
1899 
1900         fib6_walker_link(net, w);
1901         res = fib6_walk_continue(w);
1902         if (res <= 0)
1903                 fib6_walker_unlink(net, w);
1904         return res;
1905 }
1906 
1907 static int fib6_clean_node(struct fib6_walker *w)
1908 {
1909         int res;
1910         struct rt6_info *rt;
1911         struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
1912         struct nl_info info = {
1913                 .nl_net = c->net,
1914         };
1915 
1916         if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
1917             w->node->fn_sernum != c->sernum)
1918                 w->node->fn_sernum = c->sernum;
1919 
1920         if (!c->func) {
1921                 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
1922                 w->leaf = NULL;
1923                 return 0;
1924         }
1925 
1926         for_each_fib6_walker_rt(w) {
1927                 res = c->func(rt, c->arg);
1928                 if (res == -1) {
1929                         w->leaf = rt;
1930                         res = fib6_del(rt, &info);
1931                         if (res) {
1932 #if RT6_DEBUG >= 2
1933                                 pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1934                                          __func__, rt,
1935                                          rcu_access_pointer(rt->rt6i_node),
1936                                          res);
1937 #endif
1938                                 continue;
1939                         }
1940                         return 0;
1941                 } else if (res == -2) {
1942                         if (WARN_ON(!rt->rt6i_nsiblings))
1943                                 continue;
1944                         rt = list_last_entry(&rt->rt6i_siblings,
1945                                              struct rt6_info, rt6i_siblings);
1946                         continue;
1947                 }
1948                 WARN_ON(res != 0);
1949         }
1950         w->leaf = rt;
1951         return 0;
1952 }
1953 
1954 /*
1955  *      Convenient frontend to tree walker.
1956  *
1957  *      func is called on each route.
1958  *              It may return -2 -> skip multipath route.
1959  *                            -1 -> delete this route.
1960  *                            0  -> continue walking
1961  */
1962 
1963 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1964                             int (*func)(struct rt6_info *, void *arg),
1965                             int sernum, void *arg)
1966 {
1967         struct fib6_cleaner c;
1968 
1969         c.w.root = root;
1970         c.w.func = fib6_clean_node;
1971         c.w.count = 0;
1972         c.w.skip = 0;
1973         c.func = func;
1974         c.sernum = sernum;
1975         c.arg = arg;
1976         c.net = net;
1977 
1978         fib6_walk(net, &c.w);
1979 }
1980 
1981 static void __fib6_clean_all(struct net *net,
1982                              int (*func)(struct rt6_info *, void *),
1983                              int sernum, void *arg)
1984 {
1985         struct fib6_table *table;
1986         struct hlist_head *head;
1987         unsigned int h;
1988 
1989         rcu_read_lock();
1990         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1991                 head = &net->ipv6.fib_table_hash[h];
1992                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1993                         spin_lock_bh(&table->tb6_lock);
1994                         fib6_clean_tree(net, &table->tb6_root,
1995                                         func, sernum, arg);
1996                         spin_unlock_bh(&table->tb6_lock);
1997                 }
1998         }
1999         rcu_read_unlock();
2000 }
2001 
2002 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *),
2003                     void *arg)
2004 {
2005         __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
2006 }
2007 
2008 static void fib6_flush_trees(struct net *net)
2009 {
2010         int new_sernum = fib6_new_sernum(net);
2011 
2012         __fib6_clean_all(net, NULL, new_sernum, NULL);
2013 }
2014 
2015 /*
2016  *      Garbage collection
2017  */
2018 
2019 static int fib6_age(struct rt6_info *rt, void *arg)
2020 {
2021         struct fib6_gc_args *gc_args = arg;
2022         unsigned long now = jiffies;
2023 
2024         /*
2025          *      check addrconf expiration here.
2026          *      Routes are expired even if they are in use.
2027          */
2028 
2029         if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
2030                 if (time_after(now, rt->dst.expires)) {
2031                         RT6_TRACE("expiring %p\n", rt);
2032                         return -1;
2033                 }
2034                 gc_args->more++;
2035         }
2036 
2037         /*      Also age clones in the exception table.
2038          *      Note, that clones are aged out
2039          *      only if they are not in use now.
2040          */
2041         rt6_age_exceptions(rt, gc_args, now);
2042 
2043         return 0;
2044 }
2045 
2046 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
2047 {
2048         struct fib6_gc_args gc_args;
2049         unsigned long now;
2050 
2051         if (force) {
2052                 spin_lock_bh(&net->ipv6.fib6_gc_lock);
2053         } else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
2054                 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
2055                 return;
2056         }
2057         gc_args.timeout = expires ? (int)expires :
2058                           net->ipv6.sysctl.ip6_rt_gc_interval;
2059         gc_args.more = 0;
2060 
2061         fib6_clean_all(net, fib6_age, &gc_args);
2062         now = jiffies;
2063         net->ipv6.ip6_rt_last_gc = now;
2064 
2065         if (gc_args.more)
2066                 mod_timer(&net->ipv6.ip6_fib_timer,
2067                           round_jiffies(now
2068                                         + net->ipv6.sysctl.ip6_rt_gc_interval));
2069         else
2070                 del_timer(&net->ipv6.ip6_fib_timer);
2071         spin_unlock_bh(&net->ipv6.fib6_gc_lock);
2072 }
2073 
2074 static void fib6_gc_timer_cb(struct timer_list *t)
2075 {
2076         struct net *arg = from_timer(arg, t, ipv6.ip6_fib_timer);
2077 
2078         fib6_run_gc(0, arg, true);
2079 }
2080 
2081 static int __net_init fib6_net_init(struct net *net)
2082 {
2083         size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
2084         int err;
2085 
2086         err = fib6_notifier_init(net);
2087         if (err)
2088                 return err;
2089 
2090         spin_lock_init(&net->ipv6.fib6_gc_lock);
2091         rwlock_init(&net->ipv6.fib6_walker_lock);
2092         INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
2093         timer_setup(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, 0);
2094 
2095         net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
2096         if (!net->ipv6.rt6_stats)
2097                 goto out_timer;
2098 
2099         /* Avoid false sharing : Use at least a full cache line */
2100         size = max_t(size_t, size, L1_CACHE_BYTES);
2101 
2102         net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
2103         if (!net->ipv6.fib_table_hash)
2104                 goto out_rt6_stats;
2105 
2106         net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
2107                                           GFP_KERNEL);
2108         if (!net->ipv6.fib6_main_tbl)
2109                 goto out_fib_table_hash;
2110 
2111         net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
2112         rcu_assign_pointer(net->ipv6.fib6_main_tbl->tb6_root.leaf,
2113                            net->ipv6.ip6_null_entry);
2114         net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
2115                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2116         inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
2117 
2118 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2119         net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
2120                                            GFP_KERNEL);
2121         if (!net->ipv6.fib6_local_tbl)
2122                 goto out_fib6_main_tbl;
2123         net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
2124         rcu_assign_pointer(net->ipv6.fib6_local_tbl->tb6_root.leaf,
2125                            net->ipv6.ip6_null_entry);
2126         net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
2127                 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
2128         inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
2129 #endif
2130         fib6_tables_init(net);
2131 
2132         return 0;
2133 
2134 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
2135 out_fib6_main_tbl:
2136         kfree(net->ipv6.fib6_main_tbl);
2137 #endif
2138 out_fib_table_hash:
2139         kfree(net->ipv6.fib_table_hash);
2140 out_rt6_stats:
2141         kfree(net->ipv6.rt6_stats);
2142 out_timer:
2143         fib6_notifier_exit(net);
2144         return -ENOMEM;
2145 }
2146 
2147 static void fib6_net_exit(struct net *net)
2148 {
2149         unsigned int i;
2150 
2151         del_timer_sync(&net->ipv6.ip6_fib_timer);
2152 
2153         for (i = 0; i < FIB6_TABLE_HASHSZ; i++) {
2154                 struct hlist_head *head = &net->ipv6.fib_table_hash[i];
2155                 struct hlist_node *tmp;
2156                 struct fib6_table *tb;
2157 
2158                 hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
2159                         hlist_del(&tb->tb6_hlist);
2160                         fib6_free_table(tb);
2161                 }
2162         }
2163 
2164         kfree(net->ipv6.fib_table_hash);
2165         kfree(net->ipv6.rt6_stats);
2166         fib6_notifier_exit(net);
2167 }
2168 
2169 static struct pernet_operations fib6_net_ops = {
2170         .init = fib6_net_init,
2171         .exit = fib6_net_exit,
2172 };
2173 
2174 int __init fib6_init(void)
2175 {
2176         int ret = -ENOMEM;
2177 
2178         fib6_node_kmem = kmem_cache_create("fib6_nodes",
2179                                            sizeof(struct fib6_node),
2180                                            0, SLAB_HWCACHE_ALIGN,
2181                                            NULL);
2182         if (!fib6_node_kmem)
2183                 goto out;
2184 
2185         ret = register_pernet_subsys(&fib6_net_ops);
2186         if (ret)
2187                 goto out_kmem_cache_create;
2188 
2189         ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETROUTE, NULL,
2190                                    inet6_dump_fib, 0);
2191         if (ret)
2192                 goto out_unregister_subsys;
2193 
2194         __fib6_flush_trees = fib6_flush_trees;
2195 out:
2196         return ret;
2197 
2198 out_unregister_subsys:
2199         unregister_pernet_subsys(&fib6_net_ops);
2200 out_kmem_cache_create:
2201         kmem_cache_destroy(fib6_node_kmem);
2202         goto out;
2203 }
2204 
2205 void fib6_gc_cleanup(void)
2206 {
2207         unregister_pernet_subsys(&fib6_net_ops);
2208         kmem_cache_destroy(fib6_node_kmem);
2209 }
2210 
2211 #ifdef CONFIG_PROC_FS
2212 
2213 struct ipv6_route_iter {
2214         struct seq_net_private p;
2215         struct fib6_walker w;
2216         loff_t skip;
2217         struct fib6_table *tbl;
2218         int sernum;
2219 };
2220 
2221 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2222 {
2223         struct rt6_info *rt = v;
2224         struct ipv6_route_iter *iter = seq->private;
2225 
2226         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
2227 
2228 #ifdef CONFIG_IPV6_SUBTREES
2229         seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
2230 #else
2231         seq_puts(seq, "00000000000000000000000000000000 00 ");
2232 #endif
2233         if (rt->rt6i_flags & RTF_GATEWAY)
2234                 seq_printf(seq, "%pi6", &rt->rt6i_gateway);
2235         else
2236                 seq_puts(seq, "00000000000000000000000000000000");
2237 
2238         seq_printf(seq, " %08x %08x %08x %08x %8s\n",
2239                    rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
2240                    rt->dst.__use, rt->rt6i_flags,
2241                    rt->dst.dev ? rt->dst.dev->name : "");
2242         iter->w.leaf = NULL;
2243         return 0;
2244 }
2245 
2246 static int ipv6_route_yield(struct fib6_walker *w)
2247 {
2248         struct ipv6_route_iter *iter = w->args;
2249 
2250         if (!iter->skip)
2251                 return 1;
2252 
2253         do {
2254                 iter->w.leaf = rcu_dereference_protected(
2255                                 iter->w.leaf->rt6_next,
2256                                 lockdep_is_held(&iter->tbl->tb6_lock));
2257                 iter->skip--;
2258                 if (!iter->skip && iter->w.leaf)
2259                         return 1;
2260         } while (iter->w.leaf);
2261 
2262         return 0;
2263 }
2264 
2265 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
2266                                       struct net *net)
2267 {
2268         memset(&iter->w, 0, sizeof(iter->w));
2269         iter->w.func = ipv6_route_yield;
2270         iter->w.root = &iter->tbl->tb6_root;
2271         iter->w.state = FWS_INIT;
2272         iter->w.node = iter->w.root;
2273         iter->w.args = iter;
2274         iter->sernum = iter->w.root->fn_sernum;
2275         INIT_LIST_HEAD(&iter->w.lh);
2276         fib6_walker_link(net, &iter->w);
2277 }
2278 
2279 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
2280                                                     struct net *net)
2281 {
2282         unsigned int h;
2283         struct hlist_node *node;
2284 
2285         if (tbl) {
2286                 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
2287                 node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
2288         } else {
2289                 h = 0;
2290                 node = NULL;
2291         }
2292 
2293         while (!node && h < FIB6_TABLE_HASHSZ) {
2294                 node = rcu_dereference_bh(
2295                         hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
2296         }
2297         return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
2298 }
2299 
2300 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
2301 {
2302         if (iter->sernum != iter->w.root->fn_sernum) {
2303                 iter->sernum = iter->w.root->fn_sernum;
2304                 iter->w.state = FWS_INIT;
2305                 iter->w.node = iter->w.root;
2306                 WARN_ON(iter->w.skip);
2307                 iter->w.skip = iter->w.count;
2308         }
2309 }
2310 
2311 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2312 {
2313         int r;
2314         struct rt6_info *n;
2315         struct net *net = seq_file_net(seq);
2316         struct ipv6_route_iter *iter = seq->private;
2317 
2318         if (!v)
2319                 goto iter_table;
2320 
2321         n = rcu_dereference_bh(((struct rt6_info *)v)->rt6_next);
2322         if (n) {
2323                 ++*pos;
2324                 return n;
2325         }
2326 
2327 iter_table:
2328         ipv6_route_check_sernum(iter);
2329         spin_lock_bh(&iter->tbl->tb6_lock);
2330         r = fib6_walk_continue(&iter->w);
2331         spin_unlock_bh(&iter->tbl->tb6_lock);
2332         if (r > 0) {
2333                 if (v)
2334                         ++*pos;
2335                 return iter->w.leaf;
2336         } else if (r < 0) {
2337                 fib6_walker_unlink(net, &iter->w);
2338                 return NULL;
2339         }
2340         fib6_walker_unlink(net, &iter->w);
2341 
2342         iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
2343         if (!iter->tbl)
2344                 return NULL;
2345 
2346         ipv6_route_seq_setup_walk(iter, net);
2347         goto iter_table;
2348 }
2349 
2350 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
2351         __acquires(RCU_BH)
2352 {
2353         struct net *net = seq_file_net(seq);
2354         struct ipv6_route_iter *iter = seq->private;
2355 
2356         rcu_read_lock_bh();
2357         iter->tbl = ipv6_route_seq_next_table(NULL, net);
2358         iter->skip = *pos;
2359 
2360         if (iter->tbl) {
2361                 ipv6_route_seq_setup_walk(iter, net);
2362                 return ipv6_route_seq_next(seq, NULL, pos);
2363         } else {
2364                 return NULL;
2365         }
2366 }
2367 
2368 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
2369 {
2370         struct fib6_walker *w = &iter->w;
2371         return w->node && !(w->state == FWS_U && w->node == w->root);
2372 }
2373 
2374 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2375         __releases(RCU_BH)
2376 {
2377         struct net *net = seq_file_net(seq);
2378         struct ipv6_route_iter *iter = seq->private;
2379 
2380         if (ipv6_route_iter_active(iter))
2381                 fib6_walker_unlink(net, &iter->w);
2382 
2383         rcu_read_unlock_bh();
2384 }
2385 
2386 static const struct seq_operations ipv6_route_seq_ops = {
2387         .start  = ipv6_route_seq_start,
2388         .next   = ipv6_route_seq_next,
2389         .stop   = ipv6_route_seq_stop,
2390         .show   = ipv6_route_seq_show
2391 };
2392 
2393 int ipv6_route_open(struct inode *inode, struct file *file)
2394 {
2395         return seq_open_net(inode, file, &ipv6_route_seq_ops,
2396                             sizeof(struct ipv6_route_iter));
2397 }
2398 
2399 #endif /* CONFIG_PROC_FS */
2400 

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