xref: /openbmc/linux/net/ipv6/ip6_fib.c (revision 4f205687)
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 
37 #include <net/ip6_fib.h>
38 #include <net/ip6_route.h>
39 
40 #define RT6_DEBUG 2
41 
42 #if RT6_DEBUG >= 3
43 #define RT6_TRACE(x...) pr_debug(x)
44 #else
45 #define RT6_TRACE(x...) do { ; } while (0)
46 #endif
47 
48 static struct kmem_cache *fib6_node_kmem __read_mostly;
49 
50 struct fib6_cleaner {
51 	struct fib6_walker w;
52 	struct net *net;
53 	int (*func)(struct rt6_info *, void *arg);
54 	int sernum;
55 	void *arg;
56 };
57 
58 #ifdef CONFIG_IPV6_SUBTREES
59 #define FWS_INIT FWS_S
60 #else
61 #define FWS_INIT FWS_L
62 #endif
63 
64 static void fib6_prune_clones(struct net *net, struct fib6_node *fn);
65 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
66 static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
67 static int fib6_walk(struct net *net, struct fib6_walker *w);
68 static int fib6_walk_continue(struct fib6_walker *w);
69 
70 /*
71  *	A routing update causes an increase of the serial number on the
72  *	affected subtree. This allows for cached routes to be asynchronously
73  *	tested when modifications are made to the destination cache as a
74  *	result of redirects, path MTU changes, etc.
75  */
76 
77 static void fib6_gc_timer_cb(unsigned long arg);
78 
79 #define FOR_WALKERS(net, w) \
80 	list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)
81 
82 static void fib6_walker_link(struct net *net, struct fib6_walker *w)
83 {
84 	write_lock_bh(&net->ipv6.fib6_walker_lock);
85 	list_add(&w->lh, &net->ipv6.fib6_walkers);
86 	write_unlock_bh(&net->ipv6.fib6_walker_lock);
87 }
88 
89 static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
90 {
91 	write_lock_bh(&net->ipv6.fib6_walker_lock);
92 	list_del(&w->lh);
93 	write_unlock_bh(&net->ipv6.fib6_walker_lock);
94 }
95 
96 static int fib6_new_sernum(struct net *net)
97 {
98 	int new, old;
99 
100 	do {
101 		old = atomic_read(&net->ipv6.fib6_sernum);
102 		new = old < INT_MAX ? old + 1 : 1;
103 	} while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
104 				old, new) != old);
105 	return new;
106 }
107 
108 enum {
109 	FIB6_NO_SERNUM_CHANGE = 0,
110 };
111 
112 /*
113  *	Auxiliary address test functions for the radix tree.
114  *
115  *	These assume a 32bit processor (although it will work on
116  *	64bit processors)
117  */
118 
119 /*
120  *	test bit
121  */
122 #if defined(__LITTLE_ENDIAN)
123 # define BITOP_BE32_SWIZZLE	(0x1F & ~7)
124 #else
125 # define BITOP_BE32_SWIZZLE	0
126 #endif
127 
128 static __be32 addr_bit_set(const void *token, int fn_bit)
129 {
130 	const __be32 *addr = token;
131 	/*
132 	 * Here,
133 	 *	1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
134 	 * is optimized version of
135 	 *	htonl(1 << ((~fn_bit)&0x1F))
136 	 * See include/asm-generic/bitops/le.h.
137 	 */
138 	return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
139 	       addr[fn_bit >> 5];
140 }
141 
142 static struct fib6_node *node_alloc(void)
143 {
144 	struct fib6_node *fn;
145 
146 	fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
147 
148 	return fn;
149 }
150 
151 static void node_free(struct fib6_node *fn)
152 {
153 	kmem_cache_free(fib6_node_kmem, fn);
154 }
155 
156 static void rt6_rcu_free(struct rt6_info *rt)
157 {
158 	call_rcu(&rt->dst.rcu_head, dst_rcu_free);
159 }
160 
161 static void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
162 {
163 	int cpu;
164 
165 	if (!non_pcpu_rt->rt6i_pcpu)
166 		return;
167 
168 	for_each_possible_cpu(cpu) {
169 		struct rt6_info **ppcpu_rt;
170 		struct rt6_info *pcpu_rt;
171 
172 		ppcpu_rt = per_cpu_ptr(non_pcpu_rt->rt6i_pcpu, cpu);
173 		pcpu_rt = *ppcpu_rt;
174 		if (pcpu_rt) {
175 			rt6_rcu_free(pcpu_rt);
176 			*ppcpu_rt = NULL;
177 		}
178 	}
179 
180 	free_percpu(non_pcpu_rt->rt6i_pcpu);
181 	non_pcpu_rt->rt6i_pcpu = NULL;
182 }
183 
184 static void rt6_release(struct rt6_info *rt)
185 {
186 	if (atomic_dec_and_test(&rt->rt6i_ref)) {
187 		rt6_free_pcpu(rt);
188 		rt6_rcu_free(rt);
189 	}
190 }
191 
192 static void fib6_link_table(struct net *net, struct fib6_table *tb)
193 {
194 	unsigned int h;
195 
196 	/*
197 	 * Initialize table lock at a single place to give lockdep a key,
198 	 * tables aren't visible prior to being linked to the list.
199 	 */
200 	rwlock_init(&tb->tb6_lock);
201 
202 	h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
203 
204 	/*
205 	 * No protection necessary, this is the only list mutatation
206 	 * operation, tables never disappear once they exist.
207 	 */
208 	hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
209 }
210 
211 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
212 
213 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
214 {
215 	struct fib6_table *table;
216 
217 	table = kzalloc(sizeof(*table), GFP_ATOMIC);
218 	if (table) {
219 		table->tb6_id = id;
220 		table->tb6_root.leaf = net->ipv6.ip6_null_entry;
221 		table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
222 		inet_peer_base_init(&table->tb6_peers);
223 	}
224 
225 	return table;
226 }
227 
228 struct fib6_table *fib6_new_table(struct net *net, u32 id)
229 {
230 	struct fib6_table *tb;
231 
232 	if (id == 0)
233 		id = RT6_TABLE_MAIN;
234 	tb = fib6_get_table(net, id);
235 	if (tb)
236 		return tb;
237 
238 	tb = fib6_alloc_table(net, id);
239 	if (tb)
240 		fib6_link_table(net, tb);
241 
242 	return tb;
243 }
244 EXPORT_SYMBOL_GPL(fib6_new_table);
245 
246 struct fib6_table *fib6_get_table(struct net *net, u32 id)
247 {
248 	struct fib6_table *tb;
249 	struct hlist_head *head;
250 	unsigned int h;
251 
252 	if (id == 0)
253 		id = RT6_TABLE_MAIN;
254 	h = id & (FIB6_TABLE_HASHSZ - 1);
255 	rcu_read_lock();
256 	head = &net->ipv6.fib_table_hash[h];
257 	hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
258 		if (tb->tb6_id == id) {
259 			rcu_read_unlock();
260 			return tb;
261 		}
262 	}
263 	rcu_read_unlock();
264 
265 	return NULL;
266 }
267 EXPORT_SYMBOL_GPL(fib6_get_table);
268 
269 static void __net_init fib6_tables_init(struct net *net)
270 {
271 	fib6_link_table(net, net->ipv6.fib6_main_tbl);
272 	fib6_link_table(net, net->ipv6.fib6_local_tbl);
273 }
274 #else
275 
276 struct fib6_table *fib6_new_table(struct net *net, u32 id)
277 {
278 	return fib6_get_table(net, id);
279 }
280 
281 struct fib6_table *fib6_get_table(struct net *net, u32 id)
282 {
283 	  return net->ipv6.fib6_main_tbl;
284 }
285 
286 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
287 				   int flags, pol_lookup_t lookup)
288 {
289 	struct rt6_info *rt;
290 
291 	rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
292 	if (rt->rt6i_flags & RTF_REJECT &&
293 	    rt->dst.error == -EAGAIN) {
294 		ip6_rt_put(rt);
295 		rt = net->ipv6.ip6_null_entry;
296 		dst_hold(&rt->dst);
297 	}
298 
299 	return &rt->dst;
300 }
301 
302 static void __net_init fib6_tables_init(struct net *net)
303 {
304 	fib6_link_table(net, net->ipv6.fib6_main_tbl);
305 }
306 
307 #endif
308 
309 static int fib6_dump_node(struct fib6_walker *w)
310 {
311 	int res;
312 	struct rt6_info *rt;
313 
314 	for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
315 		res = rt6_dump_route(rt, w->args);
316 		if (res < 0) {
317 			/* Frame is full, suspend walking */
318 			w->leaf = rt;
319 			return 1;
320 		}
321 	}
322 	w->leaf = NULL;
323 	return 0;
324 }
325 
326 static void fib6_dump_end(struct netlink_callback *cb)
327 {
328 	struct net *net = sock_net(cb->skb->sk);
329 	struct fib6_walker *w = (void *)cb->args[2];
330 
331 	if (w) {
332 		if (cb->args[4]) {
333 			cb->args[4] = 0;
334 			fib6_walker_unlink(net, w);
335 		}
336 		cb->args[2] = 0;
337 		kfree(w);
338 	}
339 	cb->done = (void *)cb->args[3];
340 	cb->args[1] = 3;
341 }
342 
343 static int fib6_dump_done(struct netlink_callback *cb)
344 {
345 	fib6_dump_end(cb);
346 	return cb->done ? cb->done(cb) : 0;
347 }
348 
349 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
350 			   struct netlink_callback *cb)
351 {
352 	struct net *net = sock_net(skb->sk);
353 	struct fib6_walker *w;
354 	int res;
355 
356 	w = (void *)cb->args[2];
357 	w->root = &table->tb6_root;
358 
359 	if (cb->args[4] == 0) {
360 		w->count = 0;
361 		w->skip = 0;
362 
363 		read_lock_bh(&table->tb6_lock);
364 		res = fib6_walk(net, w);
365 		read_unlock_bh(&table->tb6_lock);
366 		if (res > 0) {
367 			cb->args[4] = 1;
368 			cb->args[5] = w->root->fn_sernum;
369 		}
370 	} else {
371 		if (cb->args[5] != w->root->fn_sernum) {
372 			/* Begin at the root if the tree changed */
373 			cb->args[5] = w->root->fn_sernum;
374 			w->state = FWS_INIT;
375 			w->node = w->root;
376 			w->skip = w->count;
377 		} else
378 			w->skip = 0;
379 
380 		read_lock_bh(&table->tb6_lock);
381 		res = fib6_walk_continue(w);
382 		read_unlock_bh(&table->tb6_lock);
383 		if (res <= 0) {
384 			fib6_walker_unlink(net, w);
385 			cb->args[4] = 0;
386 		}
387 	}
388 
389 	return res;
390 }
391 
392 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
393 {
394 	struct net *net = sock_net(skb->sk);
395 	unsigned int h, s_h;
396 	unsigned int e = 0, s_e;
397 	struct rt6_rtnl_dump_arg arg;
398 	struct fib6_walker *w;
399 	struct fib6_table *tb;
400 	struct hlist_head *head;
401 	int res = 0;
402 
403 	s_h = cb->args[0];
404 	s_e = cb->args[1];
405 
406 	w = (void *)cb->args[2];
407 	if (!w) {
408 		/* New dump:
409 		 *
410 		 * 1. hook callback destructor.
411 		 */
412 		cb->args[3] = (long)cb->done;
413 		cb->done = fib6_dump_done;
414 
415 		/*
416 		 * 2. allocate and initialize walker.
417 		 */
418 		w = kzalloc(sizeof(*w), GFP_ATOMIC);
419 		if (!w)
420 			return -ENOMEM;
421 		w->func = fib6_dump_node;
422 		cb->args[2] = (long)w;
423 	}
424 
425 	arg.skb = skb;
426 	arg.cb = cb;
427 	arg.net = net;
428 	w->args = &arg;
429 
430 	rcu_read_lock();
431 	for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
432 		e = 0;
433 		head = &net->ipv6.fib_table_hash[h];
434 		hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
435 			if (e < s_e)
436 				goto next;
437 			res = fib6_dump_table(tb, skb, cb);
438 			if (res != 0)
439 				goto out;
440 next:
441 			e++;
442 		}
443 	}
444 out:
445 	rcu_read_unlock();
446 	cb->args[1] = e;
447 	cb->args[0] = h;
448 
449 	res = res < 0 ? res : skb->len;
450 	if (res <= 0)
451 		fib6_dump_end(cb);
452 	return res;
453 }
454 
455 /*
456  *	Routing Table
457  *
458  *	return the appropriate node for a routing tree "add" operation
459  *	by either creating and inserting or by returning an existing
460  *	node.
461  */
462 
463 static struct fib6_node *fib6_add_1(struct fib6_node *root,
464 				     struct in6_addr *addr, int plen,
465 				     int offset, int allow_create,
466 				     int replace_required, int sernum)
467 {
468 	struct fib6_node *fn, *in, *ln;
469 	struct fib6_node *pn = NULL;
470 	struct rt6key *key;
471 	int	bit;
472 	__be32	dir = 0;
473 
474 	RT6_TRACE("fib6_add_1\n");
475 
476 	/* insert node in tree */
477 
478 	fn = root;
479 
480 	do {
481 		key = (struct rt6key *)((u8 *)fn->leaf + offset);
482 
483 		/*
484 		 *	Prefix match
485 		 */
486 		if (plen < fn->fn_bit ||
487 		    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
488 			if (!allow_create) {
489 				if (replace_required) {
490 					pr_warn("Can't replace route, no match found\n");
491 					return ERR_PTR(-ENOENT);
492 				}
493 				pr_warn("NLM_F_CREATE should be set when creating new route\n");
494 			}
495 			goto insert_above;
496 		}
497 
498 		/*
499 		 *	Exact match ?
500 		 */
501 
502 		if (plen == fn->fn_bit) {
503 			/* clean up an intermediate node */
504 			if (!(fn->fn_flags & RTN_RTINFO)) {
505 				rt6_release(fn->leaf);
506 				fn->leaf = NULL;
507 			}
508 
509 			fn->fn_sernum = sernum;
510 
511 			return fn;
512 		}
513 
514 		/*
515 		 *	We have more bits to go
516 		 */
517 
518 		/* Try to walk down on tree. */
519 		fn->fn_sernum = sernum;
520 		dir = addr_bit_set(addr, fn->fn_bit);
521 		pn = fn;
522 		fn = dir ? fn->right : fn->left;
523 	} while (fn);
524 
525 	if (!allow_create) {
526 		/* We should not create new node because
527 		 * NLM_F_REPLACE was specified without NLM_F_CREATE
528 		 * I assume it is safe to require NLM_F_CREATE when
529 		 * REPLACE flag is used! Later we may want to remove the
530 		 * check for replace_required, because according
531 		 * to netlink specification, NLM_F_CREATE
532 		 * MUST be specified if new route is created.
533 		 * That would keep IPv6 consistent with IPv4
534 		 */
535 		if (replace_required) {
536 			pr_warn("Can't replace route, no match found\n");
537 			return ERR_PTR(-ENOENT);
538 		}
539 		pr_warn("NLM_F_CREATE should be set when creating new route\n");
540 	}
541 	/*
542 	 *	We walked to the bottom of tree.
543 	 *	Create new leaf node without children.
544 	 */
545 
546 	ln = node_alloc();
547 
548 	if (!ln)
549 		return ERR_PTR(-ENOMEM);
550 	ln->fn_bit = plen;
551 
552 	ln->parent = pn;
553 	ln->fn_sernum = sernum;
554 
555 	if (dir)
556 		pn->right = ln;
557 	else
558 		pn->left  = ln;
559 
560 	return ln;
561 
562 
563 insert_above:
564 	/*
565 	 * split since we don't have a common prefix anymore or
566 	 * we have a less significant route.
567 	 * we've to insert an intermediate node on the list
568 	 * this new node will point to the one we need to create
569 	 * and the current
570 	 */
571 
572 	pn = fn->parent;
573 
574 	/* find 1st bit in difference between the 2 addrs.
575 
576 	   See comment in __ipv6_addr_diff: bit may be an invalid value,
577 	   but if it is >= plen, the value is ignored in any case.
578 	 */
579 
580 	bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
581 
582 	/*
583 	 *		(intermediate)[in]
584 	 *	          /	   \
585 	 *	(new leaf node)[ln] (old node)[fn]
586 	 */
587 	if (plen > bit) {
588 		in = node_alloc();
589 		ln = node_alloc();
590 
591 		if (!in || !ln) {
592 			if (in)
593 				node_free(in);
594 			if (ln)
595 				node_free(ln);
596 			return ERR_PTR(-ENOMEM);
597 		}
598 
599 		/*
600 		 * new intermediate node.
601 		 * RTN_RTINFO will
602 		 * be off since that an address that chooses one of
603 		 * the branches would not match less specific routes
604 		 * in the other branch
605 		 */
606 
607 		in->fn_bit = bit;
608 
609 		in->parent = pn;
610 		in->leaf = fn->leaf;
611 		atomic_inc(&in->leaf->rt6i_ref);
612 
613 		in->fn_sernum = sernum;
614 
615 		/* update parent pointer */
616 		if (dir)
617 			pn->right = in;
618 		else
619 			pn->left  = in;
620 
621 		ln->fn_bit = plen;
622 
623 		ln->parent = in;
624 		fn->parent = in;
625 
626 		ln->fn_sernum = sernum;
627 
628 		if (addr_bit_set(addr, bit)) {
629 			in->right = ln;
630 			in->left  = fn;
631 		} else {
632 			in->left  = ln;
633 			in->right = fn;
634 		}
635 	} else { /* plen <= bit */
636 
637 		/*
638 		 *		(new leaf node)[ln]
639 		 *	          /	   \
640 		 *	     (old node)[fn] NULL
641 		 */
642 
643 		ln = node_alloc();
644 
645 		if (!ln)
646 			return ERR_PTR(-ENOMEM);
647 
648 		ln->fn_bit = plen;
649 
650 		ln->parent = pn;
651 
652 		ln->fn_sernum = sernum;
653 
654 		if (dir)
655 			pn->right = ln;
656 		else
657 			pn->left  = ln;
658 
659 		if (addr_bit_set(&key->addr, plen))
660 			ln->right = fn;
661 		else
662 			ln->left  = fn;
663 
664 		fn->parent = ln;
665 	}
666 	return ln;
667 }
668 
669 static bool rt6_qualify_for_ecmp(struct rt6_info *rt)
670 {
671 	return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
672 	       RTF_GATEWAY;
673 }
674 
675 static void fib6_copy_metrics(u32 *mp, const struct mx6_config *mxc)
676 {
677 	int i;
678 
679 	for (i = 0; i < RTAX_MAX; i++) {
680 		if (test_bit(i, mxc->mx_valid))
681 			mp[i] = mxc->mx[i];
682 	}
683 }
684 
685 static int fib6_commit_metrics(struct dst_entry *dst, struct mx6_config *mxc)
686 {
687 	if (!mxc->mx)
688 		return 0;
689 
690 	if (dst->flags & DST_HOST) {
691 		u32 *mp = dst_metrics_write_ptr(dst);
692 
693 		if (unlikely(!mp))
694 			return -ENOMEM;
695 
696 		fib6_copy_metrics(mp, mxc);
697 	} else {
698 		dst_init_metrics(dst, mxc->mx, false);
699 
700 		/* We've stolen mx now. */
701 		mxc->mx = NULL;
702 	}
703 
704 	return 0;
705 }
706 
707 static void fib6_purge_rt(struct rt6_info *rt, struct fib6_node *fn,
708 			  struct net *net)
709 {
710 	if (atomic_read(&rt->rt6i_ref) != 1) {
711 		/* This route is used as dummy address holder in some split
712 		 * nodes. It is not leaked, but it still holds other resources,
713 		 * which must be released in time. So, scan ascendant nodes
714 		 * and replace dummy references to this route with references
715 		 * to still alive ones.
716 		 */
717 		while (fn) {
718 			if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
719 				fn->leaf = fib6_find_prefix(net, fn);
720 				atomic_inc(&fn->leaf->rt6i_ref);
721 				rt6_release(rt);
722 			}
723 			fn = fn->parent;
724 		}
725 		/* No more references are possible at this point. */
726 		BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
727 	}
728 }
729 
730 /*
731  *	Insert routing information in a node.
732  */
733 
734 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
735 			    struct nl_info *info, struct mx6_config *mxc)
736 {
737 	struct rt6_info *iter = NULL;
738 	struct rt6_info **ins;
739 	struct rt6_info **fallback_ins = NULL;
740 	int replace = (info->nlh &&
741 		       (info->nlh->nlmsg_flags & NLM_F_REPLACE));
742 	int add = (!info->nlh ||
743 		   (info->nlh->nlmsg_flags & NLM_F_CREATE));
744 	int found = 0;
745 	bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
746 	int err;
747 
748 	ins = &fn->leaf;
749 
750 	for (iter = fn->leaf; iter; iter = iter->dst.rt6_next) {
751 		/*
752 		 *	Search for duplicates
753 		 */
754 
755 		if (iter->rt6i_metric == rt->rt6i_metric) {
756 			/*
757 			 *	Same priority level
758 			 */
759 			if (info->nlh &&
760 			    (info->nlh->nlmsg_flags & NLM_F_EXCL))
761 				return -EEXIST;
762 			if (replace) {
763 				if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
764 					found++;
765 					break;
766 				}
767 				if (rt_can_ecmp)
768 					fallback_ins = fallback_ins ?: ins;
769 				goto next_iter;
770 			}
771 
772 			if (iter->dst.dev == rt->dst.dev &&
773 			    iter->rt6i_idev == rt->rt6i_idev &&
774 			    ipv6_addr_equal(&iter->rt6i_gateway,
775 					    &rt->rt6i_gateway)) {
776 				if (rt->rt6i_nsiblings)
777 					rt->rt6i_nsiblings = 0;
778 				if (!(iter->rt6i_flags & RTF_EXPIRES))
779 					return -EEXIST;
780 				if (!(rt->rt6i_flags & RTF_EXPIRES))
781 					rt6_clean_expires(iter);
782 				else
783 					rt6_set_expires(iter, rt->dst.expires);
784 				iter->rt6i_pmtu = rt->rt6i_pmtu;
785 				return -EEXIST;
786 			}
787 			/* If we have the same destination and the same metric,
788 			 * but not the same gateway, then the route we try to
789 			 * add is sibling to this route, increment our counter
790 			 * of siblings, and later we will add our route to the
791 			 * list.
792 			 * Only static routes (which don't have flag
793 			 * RTF_EXPIRES) are used for ECMPv6.
794 			 *
795 			 * To avoid long list, we only had siblings if the
796 			 * route have a gateway.
797 			 */
798 			if (rt_can_ecmp &&
799 			    rt6_qualify_for_ecmp(iter))
800 				rt->rt6i_nsiblings++;
801 		}
802 
803 		if (iter->rt6i_metric > rt->rt6i_metric)
804 			break;
805 
806 next_iter:
807 		ins = &iter->dst.rt6_next;
808 	}
809 
810 	if (fallback_ins && !found) {
811 		/* No ECMP-able route found, replace first non-ECMP one */
812 		ins = fallback_ins;
813 		iter = *ins;
814 		found++;
815 	}
816 
817 	/* Reset round-robin state, if necessary */
818 	if (ins == &fn->leaf)
819 		fn->rr_ptr = NULL;
820 
821 	/* Link this route to others same route. */
822 	if (rt->rt6i_nsiblings) {
823 		unsigned int rt6i_nsiblings;
824 		struct rt6_info *sibling, *temp_sibling;
825 
826 		/* Find the first route that have the same metric */
827 		sibling = fn->leaf;
828 		while (sibling) {
829 			if (sibling->rt6i_metric == rt->rt6i_metric &&
830 			    rt6_qualify_for_ecmp(sibling)) {
831 				list_add_tail(&rt->rt6i_siblings,
832 					      &sibling->rt6i_siblings);
833 				break;
834 			}
835 			sibling = sibling->dst.rt6_next;
836 		}
837 		/* For each sibling in the list, increment the counter of
838 		 * siblings. BUG() if counters does not match, list of siblings
839 		 * is broken!
840 		 */
841 		rt6i_nsiblings = 0;
842 		list_for_each_entry_safe(sibling, temp_sibling,
843 					 &rt->rt6i_siblings, rt6i_siblings) {
844 			sibling->rt6i_nsiblings++;
845 			BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
846 			rt6i_nsiblings++;
847 		}
848 		BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
849 	}
850 
851 	/*
852 	 *	insert node
853 	 */
854 	if (!replace) {
855 		if (!add)
856 			pr_warn("NLM_F_CREATE should be set when creating new route\n");
857 
858 add:
859 		err = fib6_commit_metrics(&rt->dst, mxc);
860 		if (err)
861 			return err;
862 
863 		rt->dst.rt6_next = iter;
864 		*ins = rt;
865 		rt->rt6i_node = fn;
866 		atomic_inc(&rt->rt6i_ref);
867 		inet6_rt_notify(RTM_NEWROUTE, rt, info, 0);
868 		info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
869 
870 		if (!(fn->fn_flags & RTN_RTINFO)) {
871 			info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
872 			fn->fn_flags |= RTN_RTINFO;
873 		}
874 
875 	} else {
876 		int nsiblings;
877 
878 		if (!found) {
879 			if (add)
880 				goto add;
881 			pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
882 			return -ENOENT;
883 		}
884 
885 		err = fib6_commit_metrics(&rt->dst, mxc);
886 		if (err)
887 			return err;
888 
889 		*ins = rt;
890 		rt->rt6i_node = fn;
891 		rt->dst.rt6_next = iter->dst.rt6_next;
892 		atomic_inc(&rt->rt6i_ref);
893 		inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
894 		if (!(fn->fn_flags & RTN_RTINFO)) {
895 			info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
896 			fn->fn_flags |= RTN_RTINFO;
897 		}
898 		nsiblings = iter->rt6i_nsiblings;
899 		fib6_purge_rt(iter, fn, info->nl_net);
900 		rt6_release(iter);
901 
902 		if (nsiblings) {
903 			/* Replacing an ECMP route, remove all siblings */
904 			ins = &rt->dst.rt6_next;
905 			iter = *ins;
906 			while (iter) {
907 				if (rt6_qualify_for_ecmp(iter)) {
908 					*ins = iter->dst.rt6_next;
909 					fib6_purge_rt(iter, fn, info->nl_net);
910 					rt6_release(iter);
911 					nsiblings--;
912 				} else {
913 					ins = &iter->dst.rt6_next;
914 				}
915 				iter = *ins;
916 			}
917 			WARN_ON(nsiblings != 0);
918 		}
919 	}
920 
921 	return 0;
922 }
923 
924 static void fib6_start_gc(struct net *net, struct rt6_info *rt)
925 {
926 	if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
927 	    (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
928 		mod_timer(&net->ipv6.ip6_fib_timer,
929 			  jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
930 }
931 
932 void fib6_force_start_gc(struct net *net)
933 {
934 	if (!timer_pending(&net->ipv6.ip6_fib_timer))
935 		mod_timer(&net->ipv6.ip6_fib_timer,
936 			  jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
937 }
938 
939 /*
940  *	Add routing information to the routing tree.
941  *	<destination addr>/<source addr>
942  *	with source addr info in sub-trees
943  */
944 
945 int fib6_add(struct fib6_node *root, struct rt6_info *rt,
946 	     struct nl_info *info, struct mx6_config *mxc)
947 {
948 	struct fib6_node *fn, *pn = NULL;
949 	int err = -ENOMEM;
950 	int allow_create = 1;
951 	int replace_required = 0;
952 	int sernum = fib6_new_sernum(info->nl_net);
953 
954 	if (WARN_ON_ONCE((rt->dst.flags & DST_NOCACHE) &&
955 			 !atomic_read(&rt->dst.__refcnt)))
956 		return -EINVAL;
957 
958 	if (info->nlh) {
959 		if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
960 			allow_create = 0;
961 		if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
962 			replace_required = 1;
963 	}
964 	if (!allow_create && !replace_required)
965 		pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
966 
967 	fn = fib6_add_1(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
968 			offsetof(struct rt6_info, rt6i_dst), allow_create,
969 			replace_required, sernum);
970 	if (IS_ERR(fn)) {
971 		err = PTR_ERR(fn);
972 		fn = NULL;
973 		goto out;
974 	}
975 
976 	pn = fn;
977 
978 #ifdef CONFIG_IPV6_SUBTREES
979 	if (rt->rt6i_src.plen) {
980 		struct fib6_node *sn;
981 
982 		if (!fn->subtree) {
983 			struct fib6_node *sfn;
984 
985 			/*
986 			 * Create subtree.
987 			 *
988 			 *		fn[main tree]
989 			 *		|
990 			 *		sfn[subtree root]
991 			 *		   \
992 			 *		    sn[new leaf node]
993 			 */
994 
995 			/* Create subtree root node */
996 			sfn = node_alloc();
997 			if (!sfn)
998 				goto st_failure;
999 
1000 			sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
1001 			atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
1002 			sfn->fn_flags = RTN_ROOT;
1003 			sfn->fn_sernum = sernum;
1004 
1005 			/* Now add the first leaf node to new subtree */
1006 
1007 			sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
1008 					rt->rt6i_src.plen,
1009 					offsetof(struct rt6_info, rt6i_src),
1010 					allow_create, replace_required, sernum);
1011 
1012 			if (IS_ERR(sn)) {
1013 				/* If it is failed, discard just allocated
1014 				   root, and then (in st_failure) stale node
1015 				   in main tree.
1016 				 */
1017 				node_free(sfn);
1018 				err = PTR_ERR(sn);
1019 				goto st_failure;
1020 			}
1021 
1022 			/* Now link new subtree to main tree */
1023 			sfn->parent = fn;
1024 			fn->subtree = sfn;
1025 		} else {
1026 			sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
1027 					rt->rt6i_src.plen,
1028 					offsetof(struct rt6_info, rt6i_src),
1029 					allow_create, replace_required, sernum);
1030 
1031 			if (IS_ERR(sn)) {
1032 				err = PTR_ERR(sn);
1033 				goto st_failure;
1034 			}
1035 		}
1036 
1037 		if (!fn->leaf) {
1038 			fn->leaf = rt;
1039 			atomic_inc(&rt->rt6i_ref);
1040 		}
1041 		fn = sn;
1042 	}
1043 #endif
1044 
1045 	err = fib6_add_rt2node(fn, rt, info, mxc);
1046 	if (!err) {
1047 		fib6_start_gc(info->nl_net, rt);
1048 		if (!(rt->rt6i_flags & RTF_CACHE))
1049 			fib6_prune_clones(info->nl_net, pn);
1050 		rt->dst.flags &= ~DST_NOCACHE;
1051 	}
1052 
1053 out:
1054 	if (err) {
1055 #ifdef CONFIG_IPV6_SUBTREES
1056 		/*
1057 		 * If fib6_add_1 has cleared the old leaf pointer in the
1058 		 * super-tree leaf node we have to find a new one for it.
1059 		 */
1060 		if (pn != fn && pn->leaf == rt) {
1061 			pn->leaf = NULL;
1062 			atomic_dec(&rt->rt6i_ref);
1063 		}
1064 		if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
1065 			pn->leaf = fib6_find_prefix(info->nl_net, pn);
1066 #if RT6_DEBUG >= 2
1067 			if (!pn->leaf) {
1068 				WARN_ON(pn->leaf == NULL);
1069 				pn->leaf = info->nl_net->ipv6.ip6_null_entry;
1070 			}
1071 #endif
1072 			atomic_inc(&pn->leaf->rt6i_ref);
1073 		}
1074 #endif
1075 		if (!(rt->dst.flags & DST_NOCACHE))
1076 			dst_free(&rt->dst);
1077 	}
1078 	return err;
1079 
1080 #ifdef CONFIG_IPV6_SUBTREES
1081 	/* Subtree creation failed, probably main tree node
1082 	   is orphan. If it is, shoot it.
1083 	 */
1084 st_failure:
1085 	if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
1086 		fib6_repair_tree(info->nl_net, fn);
1087 	if (!(rt->dst.flags & DST_NOCACHE))
1088 		dst_free(&rt->dst);
1089 	return err;
1090 #endif
1091 }
1092 
1093 /*
1094  *	Routing tree lookup
1095  *
1096  */
1097 
1098 struct lookup_args {
1099 	int			offset;		/* key offset on rt6_info	*/
1100 	const struct in6_addr	*addr;		/* search key			*/
1101 };
1102 
1103 static struct fib6_node *fib6_lookup_1(struct fib6_node *root,
1104 				       struct lookup_args *args)
1105 {
1106 	struct fib6_node *fn;
1107 	__be32 dir;
1108 
1109 	if (unlikely(args->offset == 0))
1110 		return NULL;
1111 
1112 	/*
1113 	 *	Descend on a tree
1114 	 */
1115 
1116 	fn = root;
1117 
1118 	for (;;) {
1119 		struct fib6_node *next;
1120 
1121 		dir = addr_bit_set(args->addr, fn->fn_bit);
1122 
1123 		next = dir ? fn->right : fn->left;
1124 
1125 		if (next) {
1126 			fn = next;
1127 			continue;
1128 		}
1129 		break;
1130 	}
1131 
1132 	while (fn) {
1133 		if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
1134 			struct rt6key *key;
1135 
1136 			key = (struct rt6key *) ((u8 *) fn->leaf +
1137 						 args->offset);
1138 
1139 			if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
1140 #ifdef CONFIG_IPV6_SUBTREES
1141 				if (fn->subtree) {
1142 					struct fib6_node *sfn;
1143 					sfn = fib6_lookup_1(fn->subtree,
1144 							    args + 1);
1145 					if (!sfn)
1146 						goto backtrack;
1147 					fn = sfn;
1148 				}
1149 #endif
1150 				if (fn->fn_flags & RTN_RTINFO)
1151 					return fn;
1152 			}
1153 		}
1154 #ifdef CONFIG_IPV6_SUBTREES
1155 backtrack:
1156 #endif
1157 		if (fn->fn_flags & RTN_ROOT)
1158 			break;
1159 
1160 		fn = fn->parent;
1161 	}
1162 
1163 	return NULL;
1164 }
1165 
1166 struct fib6_node *fib6_lookup(struct fib6_node *root, const struct in6_addr *daddr,
1167 			      const struct in6_addr *saddr)
1168 {
1169 	struct fib6_node *fn;
1170 	struct lookup_args args[] = {
1171 		{
1172 			.offset = offsetof(struct rt6_info, rt6i_dst),
1173 			.addr = daddr,
1174 		},
1175 #ifdef CONFIG_IPV6_SUBTREES
1176 		{
1177 			.offset = offsetof(struct rt6_info, rt6i_src),
1178 			.addr = saddr,
1179 		},
1180 #endif
1181 		{
1182 			.offset = 0,	/* sentinel */
1183 		}
1184 	};
1185 
1186 	fn = fib6_lookup_1(root, daddr ? args : args + 1);
1187 	if (!fn || fn->fn_flags & RTN_TL_ROOT)
1188 		fn = root;
1189 
1190 	return fn;
1191 }
1192 
1193 /*
1194  *	Get node with specified destination prefix (and source prefix,
1195  *	if subtrees are used)
1196  */
1197 
1198 
1199 static struct fib6_node *fib6_locate_1(struct fib6_node *root,
1200 				       const struct in6_addr *addr,
1201 				       int plen, int offset)
1202 {
1203 	struct fib6_node *fn;
1204 
1205 	for (fn = root; fn ; ) {
1206 		struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
1207 
1208 		/*
1209 		 *	Prefix match
1210 		 */
1211 		if (plen < fn->fn_bit ||
1212 		    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
1213 			return NULL;
1214 
1215 		if (plen == fn->fn_bit)
1216 			return fn;
1217 
1218 		/*
1219 		 *	We have more bits to go
1220 		 */
1221 		if (addr_bit_set(addr, fn->fn_bit))
1222 			fn = fn->right;
1223 		else
1224 			fn = fn->left;
1225 	}
1226 	return NULL;
1227 }
1228 
1229 struct fib6_node *fib6_locate(struct fib6_node *root,
1230 			      const struct in6_addr *daddr, int dst_len,
1231 			      const struct in6_addr *saddr, int src_len)
1232 {
1233 	struct fib6_node *fn;
1234 
1235 	fn = fib6_locate_1(root, daddr, dst_len,
1236 			   offsetof(struct rt6_info, rt6i_dst));
1237 
1238 #ifdef CONFIG_IPV6_SUBTREES
1239 	if (src_len) {
1240 		WARN_ON(saddr == NULL);
1241 		if (fn && fn->subtree)
1242 			fn = fib6_locate_1(fn->subtree, saddr, src_len,
1243 					   offsetof(struct rt6_info, rt6i_src));
1244 	}
1245 #endif
1246 
1247 	if (fn && fn->fn_flags & RTN_RTINFO)
1248 		return fn;
1249 
1250 	return NULL;
1251 }
1252 
1253 
1254 /*
1255  *	Deletion
1256  *
1257  */
1258 
1259 static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
1260 {
1261 	if (fn->fn_flags & RTN_ROOT)
1262 		return net->ipv6.ip6_null_entry;
1263 
1264 	while (fn) {
1265 		if (fn->left)
1266 			return fn->left->leaf;
1267 		if (fn->right)
1268 			return fn->right->leaf;
1269 
1270 		fn = FIB6_SUBTREE(fn);
1271 	}
1272 	return NULL;
1273 }
1274 
1275 /*
1276  *	Called to trim the tree of intermediate nodes when possible. "fn"
1277  *	is the node we want to try and remove.
1278  */
1279 
1280 static struct fib6_node *fib6_repair_tree(struct net *net,
1281 					   struct fib6_node *fn)
1282 {
1283 	int children;
1284 	int nstate;
1285 	struct fib6_node *child, *pn;
1286 	struct fib6_walker *w;
1287 	int iter = 0;
1288 
1289 	for (;;) {
1290 		RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1291 		iter++;
1292 
1293 		WARN_ON(fn->fn_flags & RTN_RTINFO);
1294 		WARN_ON(fn->fn_flags & RTN_TL_ROOT);
1295 		WARN_ON(fn->leaf);
1296 
1297 		children = 0;
1298 		child = NULL;
1299 		if (fn->right)
1300 			child = fn->right, children |= 1;
1301 		if (fn->left)
1302 			child = fn->left, children |= 2;
1303 
1304 		if (children == 3 || FIB6_SUBTREE(fn)
1305 #ifdef CONFIG_IPV6_SUBTREES
1306 		    /* Subtree root (i.e. fn) may have one child */
1307 		    || (children && fn->fn_flags & RTN_ROOT)
1308 #endif
1309 		    ) {
1310 			fn->leaf = fib6_find_prefix(net, fn);
1311 #if RT6_DEBUG >= 2
1312 			if (!fn->leaf) {
1313 				WARN_ON(!fn->leaf);
1314 				fn->leaf = net->ipv6.ip6_null_entry;
1315 			}
1316 #endif
1317 			atomic_inc(&fn->leaf->rt6i_ref);
1318 			return fn->parent;
1319 		}
1320 
1321 		pn = fn->parent;
1322 #ifdef CONFIG_IPV6_SUBTREES
1323 		if (FIB6_SUBTREE(pn) == fn) {
1324 			WARN_ON(!(fn->fn_flags & RTN_ROOT));
1325 			FIB6_SUBTREE(pn) = NULL;
1326 			nstate = FWS_L;
1327 		} else {
1328 			WARN_ON(fn->fn_flags & RTN_ROOT);
1329 #endif
1330 			if (pn->right == fn)
1331 				pn->right = child;
1332 			else if (pn->left == fn)
1333 				pn->left = child;
1334 #if RT6_DEBUG >= 2
1335 			else
1336 				WARN_ON(1);
1337 #endif
1338 			if (child)
1339 				child->parent = pn;
1340 			nstate = FWS_R;
1341 #ifdef CONFIG_IPV6_SUBTREES
1342 		}
1343 #endif
1344 
1345 		read_lock(&net->ipv6.fib6_walker_lock);
1346 		FOR_WALKERS(net, w) {
1347 			if (!child) {
1348 				if (w->root == fn) {
1349 					w->root = w->node = NULL;
1350 					RT6_TRACE("W %p adjusted by delroot 1\n", w);
1351 				} else if (w->node == fn) {
1352 					RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1353 					w->node = pn;
1354 					w->state = nstate;
1355 				}
1356 			} else {
1357 				if (w->root == fn) {
1358 					w->root = child;
1359 					RT6_TRACE("W %p adjusted by delroot 2\n", w);
1360 				}
1361 				if (w->node == fn) {
1362 					w->node = child;
1363 					if (children&2) {
1364 						RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1365 						w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
1366 					} else {
1367 						RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1368 						w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
1369 					}
1370 				}
1371 			}
1372 		}
1373 		read_unlock(&net->ipv6.fib6_walker_lock);
1374 
1375 		node_free(fn);
1376 		if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
1377 			return pn;
1378 
1379 		rt6_release(pn->leaf);
1380 		pn->leaf = NULL;
1381 		fn = pn;
1382 	}
1383 }
1384 
1385 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1386 			   struct nl_info *info)
1387 {
1388 	struct fib6_walker *w;
1389 	struct rt6_info *rt = *rtp;
1390 	struct net *net = info->nl_net;
1391 
1392 	RT6_TRACE("fib6_del_route\n");
1393 
1394 	/* Unlink it */
1395 	*rtp = rt->dst.rt6_next;
1396 	rt->rt6i_node = NULL;
1397 	net->ipv6.rt6_stats->fib_rt_entries--;
1398 	net->ipv6.rt6_stats->fib_discarded_routes++;
1399 
1400 	/* Reset round-robin state, if necessary */
1401 	if (fn->rr_ptr == rt)
1402 		fn->rr_ptr = NULL;
1403 
1404 	/* Remove this entry from other siblings */
1405 	if (rt->rt6i_nsiblings) {
1406 		struct rt6_info *sibling, *next_sibling;
1407 
1408 		list_for_each_entry_safe(sibling, next_sibling,
1409 					 &rt->rt6i_siblings, rt6i_siblings)
1410 			sibling->rt6i_nsiblings--;
1411 		rt->rt6i_nsiblings = 0;
1412 		list_del_init(&rt->rt6i_siblings);
1413 	}
1414 
1415 	/* Adjust walkers */
1416 	read_lock(&net->ipv6.fib6_walker_lock);
1417 	FOR_WALKERS(net, w) {
1418 		if (w->state == FWS_C && w->leaf == rt) {
1419 			RT6_TRACE("walker %p adjusted by delroute\n", w);
1420 			w->leaf = rt->dst.rt6_next;
1421 			if (!w->leaf)
1422 				w->state = FWS_U;
1423 		}
1424 	}
1425 	read_unlock(&net->ipv6.fib6_walker_lock);
1426 
1427 	rt->dst.rt6_next = NULL;
1428 
1429 	/* If it was last route, expunge its radix tree node */
1430 	if (!fn->leaf) {
1431 		fn->fn_flags &= ~RTN_RTINFO;
1432 		net->ipv6.rt6_stats->fib_route_nodes--;
1433 		fn = fib6_repair_tree(net, fn);
1434 	}
1435 
1436 	fib6_purge_rt(rt, fn, net);
1437 
1438 	inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
1439 	rt6_release(rt);
1440 }
1441 
1442 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1443 {
1444 	struct net *net = info->nl_net;
1445 	struct fib6_node *fn = rt->rt6i_node;
1446 	struct rt6_info **rtp;
1447 
1448 #if RT6_DEBUG >= 2
1449 	if (rt->dst.obsolete > 0) {
1450 		WARN_ON(fn);
1451 		return -ENOENT;
1452 	}
1453 #endif
1454 	if (!fn || rt == net->ipv6.ip6_null_entry)
1455 		return -ENOENT;
1456 
1457 	WARN_ON(!(fn->fn_flags & RTN_RTINFO));
1458 
1459 	if (!(rt->rt6i_flags & RTF_CACHE)) {
1460 		struct fib6_node *pn = fn;
1461 #ifdef CONFIG_IPV6_SUBTREES
1462 		/* clones of this route might be in another subtree */
1463 		if (rt->rt6i_src.plen) {
1464 			while (!(pn->fn_flags & RTN_ROOT))
1465 				pn = pn->parent;
1466 			pn = pn->parent;
1467 		}
1468 #endif
1469 		fib6_prune_clones(info->nl_net, pn);
1470 	}
1471 
1472 	/*
1473 	 *	Walk the leaf entries looking for ourself
1474 	 */
1475 
1476 	for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
1477 		if (*rtp == rt) {
1478 			fib6_del_route(fn, rtp, info);
1479 			return 0;
1480 		}
1481 	}
1482 	return -ENOENT;
1483 }
1484 
1485 /*
1486  *	Tree traversal function.
1487  *
1488  *	Certainly, it is not interrupt safe.
1489  *	However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1490  *	It means, that we can modify tree during walking
1491  *	and use this function for garbage collection, clone pruning,
1492  *	cleaning tree when a device goes down etc. etc.
1493  *
1494  *	It guarantees that every node will be traversed,
1495  *	and that it will be traversed only once.
1496  *
1497  *	Callback function w->func may return:
1498  *	0 -> continue walking.
1499  *	positive value -> walking is suspended (used by tree dumps,
1500  *	and probably by gc, if it will be split to several slices)
1501  *	negative value -> terminate walking.
1502  *
1503  *	The function itself returns:
1504  *	0   -> walk is complete.
1505  *	>0  -> walk is incomplete (i.e. suspended)
1506  *	<0  -> walk is terminated by an error.
1507  */
1508 
1509 static int fib6_walk_continue(struct fib6_walker *w)
1510 {
1511 	struct fib6_node *fn, *pn;
1512 
1513 	for (;;) {
1514 		fn = w->node;
1515 		if (!fn)
1516 			return 0;
1517 
1518 		if (w->prune && fn != w->root &&
1519 		    fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
1520 			w->state = FWS_C;
1521 			w->leaf = fn->leaf;
1522 		}
1523 		switch (w->state) {
1524 #ifdef CONFIG_IPV6_SUBTREES
1525 		case FWS_S:
1526 			if (FIB6_SUBTREE(fn)) {
1527 				w->node = FIB6_SUBTREE(fn);
1528 				continue;
1529 			}
1530 			w->state = FWS_L;
1531 #endif
1532 		case FWS_L:
1533 			if (fn->left) {
1534 				w->node = fn->left;
1535 				w->state = FWS_INIT;
1536 				continue;
1537 			}
1538 			w->state = FWS_R;
1539 		case FWS_R:
1540 			if (fn->right) {
1541 				w->node = fn->right;
1542 				w->state = FWS_INIT;
1543 				continue;
1544 			}
1545 			w->state = FWS_C;
1546 			w->leaf = fn->leaf;
1547 		case FWS_C:
1548 			if (w->leaf && fn->fn_flags & RTN_RTINFO) {
1549 				int err;
1550 
1551 				if (w->skip) {
1552 					w->skip--;
1553 					goto skip;
1554 				}
1555 
1556 				err = w->func(w);
1557 				if (err)
1558 					return err;
1559 
1560 				w->count++;
1561 				continue;
1562 			}
1563 skip:
1564 			w->state = FWS_U;
1565 		case FWS_U:
1566 			if (fn == w->root)
1567 				return 0;
1568 			pn = fn->parent;
1569 			w->node = pn;
1570 #ifdef CONFIG_IPV6_SUBTREES
1571 			if (FIB6_SUBTREE(pn) == fn) {
1572 				WARN_ON(!(fn->fn_flags & RTN_ROOT));
1573 				w->state = FWS_L;
1574 				continue;
1575 			}
1576 #endif
1577 			if (pn->left == fn) {
1578 				w->state = FWS_R;
1579 				continue;
1580 			}
1581 			if (pn->right == fn) {
1582 				w->state = FWS_C;
1583 				w->leaf = w->node->leaf;
1584 				continue;
1585 			}
1586 #if RT6_DEBUG >= 2
1587 			WARN_ON(1);
1588 #endif
1589 		}
1590 	}
1591 }
1592 
1593 static int fib6_walk(struct net *net, struct fib6_walker *w)
1594 {
1595 	int res;
1596 
1597 	w->state = FWS_INIT;
1598 	w->node = w->root;
1599 
1600 	fib6_walker_link(net, w);
1601 	res = fib6_walk_continue(w);
1602 	if (res <= 0)
1603 		fib6_walker_unlink(net, w);
1604 	return res;
1605 }
1606 
1607 static int fib6_clean_node(struct fib6_walker *w)
1608 {
1609 	int res;
1610 	struct rt6_info *rt;
1611 	struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
1612 	struct nl_info info = {
1613 		.nl_net = c->net,
1614 	};
1615 
1616 	if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
1617 	    w->node->fn_sernum != c->sernum)
1618 		w->node->fn_sernum = c->sernum;
1619 
1620 	if (!c->func) {
1621 		WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
1622 		w->leaf = NULL;
1623 		return 0;
1624 	}
1625 
1626 	for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
1627 		res = c->func(rt, c->arg);
1628 		if (res < 0) {
1629 			w->leaf = rt;
1630 			res = fib6_del(rt, &info);
1631 			if (res) {
1632 #if RT6_DEBUG >= 2
1633 				pr_debug("%s: del failed: rt=%p@%p err=%d\n",
1634 					 __func__, rt, rt->rt6i_node, res);
1635 #endif
1636 				continue;
1637 			}
1638 			return 0;
1639 		}
1640 		WARN_ON(res != 0);
1641 	}
1642 	w->leaf = rt;
1643 	return 0;
1644 }
1645 
1646 /*
1647  *	Convenient frontend to tree walker.
1648  *
1649  *	func is called on each route.
1650  *		It may return -1 -> delete this route.
1651  *		              0  -> continue walking
1652  *
1653  *	prune==1 -> only immediate children of node (certainly,
1654  *	ignoring pure split nodes) will be scanned.
1655  */
1656 
1657 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
1658 			    int (*func)(struct rt6_info *, void *arg),
1659 			    bool prune, int sernum, void *arg)
1660 {
1661 	struct fib6_cleaner c;
1662 
1663 	c.w.root = root;
1664 	c.w.func = fib6_clean_node;
1665 	c.w.prune = prune;
1666 	c.w.count = 0;
1667 	c.w.skip = 0;
1668 	c.func = func;
1669 	c.sernum = sernum;
1670 	c.arg = arg;
1671 	c.net = net;
1672 
1673 	fib6_walk(net, &c.w);
1674 }
1675 
1676 static void __fib6_clean_all(struct net *net,
1677 			     int (*func)(struct rt6_info *, void *),
1678 			     int sernum, void *arg)
1679 {
1680 	struct fib6_table *table;
1681 	struct hlist_head *head;
1682 	unsigned int h;
1683 
1684 	rcu_read_lock();
1685 	for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
1686 		head = &net->ipv6.fib_table_hash[h];
1687 		hlist_for_each_entry_rcu(table, head, tb6_hlist) {
1688 			write_lock_bh(&table->tb6_lock);
1689 			fib6_clean_tree(net, &table->tb6_root,
1690 					func, false, sernum, arg);
1691 			write_unlock_bh(&table->tb6_lock);
1692 		}
1693 	}
1694 	rcu_read_unlock();
1695 }
1696 
1697 void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *),
1698 		    void *arg)
1699 {
1700 	__fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
1701 }
1702 
1703 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1704 {
1705 	if (rt->rt6i_flags & RTF_CACHE) {
1706 		RT6_TRACE("pruning clone %p\n", rt);
1707 		return -1;
1708 	}
1709 
1710 	return 0;
1711 }
1712 
1713 static void fib6_prune_clones(struct net *net, struct fib6_node *fn)
1714 {
1715 	fib6_clean_tree(net, fn, fib6_prune_clone, true,
1716 			FIB6_NO_SERNUM_CHANGE, NULL);
1717 }
1718 
1719 static void fib6_flush_trees(struct net *net)
1720 {
1721 	int new_sernum = fib6_new_sernum(net);
1722 
1723 	__fib6_clean_all(net, NULL, new_sernum, NULL);
1724 }
1725 
1726 /*
1727  *	Garbage collection
1728  */
1729 
1730 struct fib6_gc_args
1731 {
1732 	int			timeout;
1733 	int			more;
1734 };
1735 
1736 static int fib6_age(struct rt6_info *rt, void *arg)
1737 {
1738 	struct fib6_gc_args *gc_args = arg;
1739 	unsigned long now = jiffies;
1740 
1741 	/*
1742 	 *	check addrconf expiration here.
1743 	 *	Routes are expired even if they are in use.
1744 	 *
1745 	 *	Also age clones. Note, that clones are aged out
1746 	 *	only if they are not in use now.
1747 	 */
1748 
1749 	if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
1750 		if (time_after(now, rt->dst.expires)) {
1751 			RT6_TRACE("expiring %p\n", rt);
1752 			return -1;
1753 		}
1754 		gc_args->more++;
1755 	} else if (rt->rt6i_flags & RTF_CACHE) {
1756 		if (atomic_read(&rt->dst.__refcnt) == 0 &&
1757 		    time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
1758 			RT6_TRACE("aging clone %p\n", rt);
1759 			return -1;
1760 		} else if (rt->rt6i_flags & RTF_GATEWAY) {
1761 			struct neighbour *neigh;
1762 			__u8 neigh_flags = 0;
1763 
1764 			neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
1765 			if (neigh) {
1766 				neigh_flags = neigh->flags;
1767 				neigh_release(neigh);
1768 			}
1769 			if (!(neigh_flags & NTF_ROUTER)) {
1770 				RT6_TRACE("purging route %p via non-router but gateway\n",
1771 					  rt);
1772 				return -1;
1773 			}
1774 		}
1775 		gc_args->more++;
1776 	}
1777 
1778 	return 0;
1779 }
1780 
1781 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
1782 {
1783 	struct fib6_gc_args gc_args;
1784 	unsigned long now;
1785 
1786 	if (force) {
1787 		spin_lock_bh(&net->ipv6.fib6_gc_lock);
1788 	} else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
1789 		mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
1790 		return;
1791 	}
1792 	gc_args.timeout = expires ? (int)expires :
1793 			  net->ipv6.sysctl.ip6_rt_gc_interval;
1794 
1795 	gc_args.more = icmp6_dst_gc();
1796 
1797 	fib6_clean_all(net, fib6_age, &gc_args);
1798 	now = jiffies;
1799 	net->ipv6.ip6_rt_last_gc = now;
1800 
1801 	if (gc_args.more)
1802 		mod_timer(&net->ipv6.ip6_fib_timer,
1803 			  round_jiffies(now
1804 					+ net->ipv6.sysctl.ip6_rt_gc_interval));
1805 	else
1806 		del_timer(&net->ipv6.ip6_fib_timer);
1807 	spin_unlock_bh(&net->ipv6.fib6_gc_lock);
1808 }
1809 
1810 static void fib6_gc_timer_cb(unsigned long arg)
1811 {
1812 	fib6_run_gc(0, (struct net *)arg, true);
1813 }
1814 
1815 static int __net_init fib6_net_init(struct net *net)
1816 {
1817 	size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
1818 
1819 	spin_lock_init(&net->ipv6.fib6_gc_lock);
1820 	rwlock_init(&net->ipv6.fib6_walker_lock);
1821 	INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
1822 	setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
1823 
1824 	net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
1825 	if (!net->ipv6.rt6_stats)
1826 		goto out_timer;
1827 
1828 	/* Avoid false sharing : Use at least a full cache line */
1829 	size = max_t(size_t, size, L1_CACHE_BYTES);
1830 
1831 	net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
1832 	if (!net->ipv6.fib_table_hash)
1833 		goto out_rt6_stats;
1834 
1835 	net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
1836 					  GFP_KERNEL);
1837 	if (!net->ipv6.fib6_main_tbl)
1838 		goto out_fib_table_hash;
1839 
1840 	net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
1841 	net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1842 	net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
1843 		RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1844 	inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
1845 
1846 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1847 	net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
1848 					   GFP_KERNEL);
1849 	if (!net->ipv6.fib6_local_tbl)
1850 		goto out_fib6_main_tbl;
1851 	net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
1852 	net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
1853 	net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
1854 		RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
1855 	inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
1856 #endif
1857 	fib6_tables_init(net);
1858 
1859 	return 0;
1860 
1861 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1862 out_fib6_main_tbl:
1863 	kfree(net->ipv6.fib6_main_tbl);
1864 #endif
1865 out_fib_table_hash:
1866 	kfree(net->ipv6.fib_table_hash);
1867 out_rt6_stats:
1868 	kfree(net->ipv6.rt6_stats);
1869 out_timer:
1870 	return -ENOMEM;
1871 }
1872 
1873 static void fib6_net_exit(struct net *net)
1874 {
1875 	rt6_ifdown(net, NULL);
1876 	del_timer_sync(&net->ipv6.ip6_fib_timer);
1877 
1878 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
1879 	inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
1880 	kfree(net->ipv6.fib6_local_tbl);
1881 #endif
1882 	inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
1883 	kfree(net->ipv6.fib6_main_tbl);
1884 	kfree(net->ipv6.fib_table_hash);
1885 	kfree(net->ipv6.rt6_stats);
1886 }
1887 
1888 static struct pernet_operations fib6_net_ops = {
1889 	.init = fib6_net_init,
1890 	.exit = fib6_net_exit,
1891 };
1892 
1893 int __init fib6_init(void)
1894 {
1895 	int ret = -ENOMEM;
1896 
1897 	fib6_node_kmem = kmem_cache_create("fib6_nodes",
1898 					   sizeof(struct fib6_node),
1899 					   0, SLAB_HWCACHE_ALIGN,
1900 					   NULL);
1901 	if (!fib6_node_kmem)
1902 		goto out;
1903 
1904 	ret = register_pernet_subsys(&fib6_net_ops);
1905 	if (ret)
1906 		goto out_kmem_cache_create;
1907 
1908 	ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
1909 			      NULL);
1910 	if (ret)
1911 		goto out_unregister_subsys;
1912 
1913 	__fib6_flush_trees = fib6_flush_trees;
1914 out:
1915 	return ret;
1916 
1917 out_unregister_subsys:
1918 	unregister_pernet_subsys(&fib6_net_ops);
1919 out_kmem_cache_create:
1920 	kmem_cache_destroy(fib6_node_kmem);
1921 	goto out;
1922 }
1923 
1924 void fib6_gc_cleanup(void)
1925 {
1926 	unregister_pernet_subsys(&fib6_net_ops);
1927 	kmem_cache_destroy(fib6_node_kmem);
1928 }
1929 
1930 #ifdef CONFIG_PROC_FS
1931 
1932 struct ipv6_route_iter {
1933 	struct seq_net_private p;
1934 	struct fib6_walker w;
1935 	loff_t skip;
1936 	struct fib6_table *tbl;
1937 	int sernum;
1938 };
1939 
1940 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
1941 {
1942 	struct rt6_info *rt = v;
1943 	struct ipv6_route_iter *iter = seq->private;
1944 
1945 	seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
1946 
1947 #ifdef CONFIG_IPV6_SUBTREES
1948 	seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
1949 #else
1950 	seq_puts(seq, "00000000000000000000000000000000 00 ");
1951 #endif
1952 	if (rt->rt6i_flags & RTF_GATEWAY)
1953 		seq_printf(seq, "%pi6", &rt->rt6i_gateway);
1954 	else
1955 		seq_puts(seq, "00000000000000000000000000000000");
1956 
1957 	seq_printf(seq, " %08x %08x %08x %08x %8s\n",
1958 		   rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
1959 		   rt->dst.__use, rt->rt6i_flags,
1960 		   rt->dst.dev ? rt->dst.dev->name : "");
1961 	iter->w.leaf = NULL;
1962 	return 0;
1963 }
1964 
1965 static int ipv6_route_yield(struct fib6_walker *w)
1966 {
1967 	struct ipv6_route_iter *iter = w->args;
1968 
1969 	if (!iter->skip)
1970 		return 1;
1971 
1972 	do {
1973 		iter->w.leaf = iter->w.leaf->dst.rt6_next;
1974 		iter->skip--;
1975 		if (!iter->skip && iter->w.leaf)
1976 			return 1;
1977 	} while (iter->w.leaf);
1978 
1979 	return 0;
1980 }
1981 
1982 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
1983 				      struct net *net)
1984 {
1985 	memset(&iter->w, 0, sizeof(iter->w));
1986 	iter->w.func = ipv6_route_yield;
1987 	iter->w.root = &iter->tbl->tb6_root;
1988 	iter->w.state = FWS_INIT;
1989 	iter->w.node = iter->w.root;
1990 	iter->w.args = iter;
1991 	iter->sernum = iter->w.root->fn_sernum;
1992 	INIT_LIST_HEAD(&iter->w.lh);
1993 	fib6_walker_link(net, &iter->w);
1994 }
1995 
1996 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
1997 						    struct net *net)
1998 {
1999 	unsigned int h;
2000 	struct hlist_node *node;
2001 
2002 	if (tbl) {
2003 		h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
2004 		node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
2005 	} else {
2006 		h = 0;
2007 		node = NULL;
2008 	}
2009 
2010 	while (!node && h < FIB6_TABLE_HASHSZ) {
2011 		node = rcu_dereference_bh(
2012 			hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
2013 	}
2014 	return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
2015 }
2016 
2017 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
2018 {
2019 	if (iter->sernum != iter->w.root->fn_sernum) {
2020 		iter->sernum = iter->w.root->fn_sernum;
2021 		iter->w.state = FWS_INIT;
2022 		iter->w.node = iter->w.root;
2023 		WARN_ON(iter->w.skip);
2024 		iter->w.skip = iter->w.count;
2025 	}
2026 }
2027 
2028 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2029 {
2030 	int r;
2031 	struct rt6_info *n;
2032 	struct net *net = seq_file_net(seq);
2033 	struct ipv6_route_iter *iter = seq->private;
2034 
2035 	if (!v)
2036 		goto iter_table;
2037 
2038 	n = ((struct rt6_info *)v)->dst.rt6_next;
2039 	if (n) {
2040 		++*pos;
2041 		return n;
2042 	}
2043 
2044 iter_table:
2045 	ipv6_route_check_sernum(iter);
2046 	read_lock(&iter->tbl->tb6_lock);
2047 	r = fib6_walk_continue(&iter->w);
2048 	read_unlock(&iter->tbl->tb6_lock);
2049 	if (r > 0) {
2050 		if (v)
2051 			++*pos;
2052 		return iter->w.leaf;
2053 	} else if (r < 0) {
2054 		fib6_walker_unlink(net, &iter->w);
2055 		return NULL;
2056 	}
2057 	fib6_walker_unlink(net, &iter->w);
2058 
2059 	iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
2060 	if (!iter->tbl)
2061 		return NULL;
2062 
2063 	ipv6_route_seq_setup_walk(iter, net);
2064 	goto iter_table;
2065 }
2066 
2067 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
2068 	__acquires(RCU_BH)
2069 {
2070 	struct net *net = seq_file_net(seq);
2071 	struct ipv6_route_iter *iter = seq->private;
2072 
2073 	rcu_read_lock_bh();
2074 	iter->tbl = ipv6_route_seq_next_table(NULL, net);
2075 	iter->skip = *pos;
2076 
2077 	if (iter->tbl) {
2078 		ipv6_route_seq_setup_walk(iter, net);
2079 		return ipv6_route_seq_next(seq, NULL, pos);
2080 	} else {
2081 		return NULL;
2082 	}
2083 }
2084 
2085 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
2086 {
2087 	struct fib6_walker *w = &iter->w;
2088 	return w->node && !(w->state == FWS_U && w->node == w->root);
2089 }
2090 
2091 static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2092 	__releases(RCU_BH)
2093 {
2094 	struct net *net = seq_file_net(seq);
2095 	struct ipv6_route_iter *iter = seq->private;
2096 
2097 	if (ipv6_route_iter_active(iter))
2098 		fib6_walker_unlink(net, &iter->w);
2099 
2100 	rcu_read_unlock_bh();
2101 }
2102 
2103 static const struct seq_operations ipv6_route_seq_ops = {
2104 	.start	= ipv6_route_seq_start,
2105 	.next	= ipv6_route_seq_next,
2106 	.stop	= ipv6_route_seq_stop,
2107 	.show	= ipv6_route_seq_show
2108 };
2109 
2110 int ipv6_route_open(struct inode *inode, struct file *file)
2111 {
2112 	return seq_open_net(inode, file, &ipv6_route_seq_ops,
2113 			    sizeof(struct ipv6_route_iter));
2114 }
2115 
2116 #endif /* CONFIG_PROC_FS */
2117