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