Commit 8d2ca1d7 authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by David S. Miller
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ipv6: avoid high order memory allocations for /proc/net/ipv6_route 



Dumping routes on a system with lots rt6_infos in the fibs causes up to
11-order allocations in seq_file (which fail). While we could switch
there to vmalloc we could just implement the streaming interface for
/proc/net/ipv6_route. This patch switches /proc/net/ipv6_route from
single_open_net to seq_open_net.

loff_t *pos tracks dst entries.

Also kill never used struct rt6_proc_arg and now unused function
fib6_clean_all_ro.

Cc: Ben Greear <greearb@candelatech.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6229ed1f

include/net/ip6_fib.h

+2 −4
Original line number Diff line number Diff line
@@ -280,10 +280,6 @@ struct fib6_node *fib6_locate(struct fib6_node *root, 
			      const struct in6_addr *daddr, int dst_len,

			      const struct in6_addr *saddr, int src_len);



void fib6_clean_all_ro(struct net *net,

		       int (*func)(struct rt6_info *, void *arg),

		       int prune, void *arg);



void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),

		    int prune, void *arg);
@@ -299,6 +295,8 @@ void fib6_gc_cleanup(void); 


int fib6_init(void);



int ipv6_route_open(struct inode *inode, struct file *file);



#ifdef CONFIG_IPV6_MULTIPLE_TABLES

int fib6_rules_init(void);

void fib6_rules_cleanup(void);

net/ipv6/ip6_fib.c

+172 −19
Original line number Diff line number Diff line
@@ -1529,25 +1529,6 @@ static void fib6_clean_tree(struct net *net, struct fib6_node *root, 
	fib6_walk(&c.w);

}



void fib6_clean_all_ro(struct net *net, int (*func)(struct rt6_info *, void *arg),

		    int prune, void *arg)

{

	struct fib6_table *table;

	struct hlist_head *head;

	unsigned int h;



	rcu_read_lock();

	for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {

		head = &net->ipv6.fib_table_hash[h];

		hlist_for_each_entry_rcu(table, head, tb6_hlist) {

			read_lock_bh(&table->tb6_lock);

			fib6_clean_tree(net, &table->tb6_root,

					func, prune, arg);

			read_unlock_bh(&table->tb6_lock);

		}

	}

	rcu_read_unlock();

}

void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),

		    int prune, void *arg)

{
@@ -1782,3 +1763,175 @@ void fib6_gc_cleanup(void) 
	unregister_pernet_subsys(&fib6_net_ops);

	kmem_cache_destroy(fib6_node_kmem);

}



#ifdef CONFIG_PROC_FS



struct ipv6_route_iter {

	struct seq_net_private p;

	struct fib6_walker_t w;

	loff_t skip;

	struct fib6_table *tbl;

};



static int ipv6_route_seq_show(struct seq_file *seq, void *v)

{

	struct rt6_info *rt = v;

	struct ipv6_route_iter *iter = seq->private;



	seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);



#ifdef CONFIG_IPV6_SUBTREES

	seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);

#else

	seq_puts(seq, "00000000000000000000000000000000 00 ");

#endif

	if (rt->rt6i_flags & RTF_GATEWAY)

		seq_printf(seq, "%pi6", &rt->rt6i_gateway);

	else

		seq_puts(seq, "00000000000000000000000000000000");



	seq_printf(seq, " %08x %08x %08x %08x %8s\n",

		   rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),

		   rt->dst.__use, rt->rt6i_flags,

		   rt->dst.dev ? rt->dst.dev->name : "");

	iter->w.leaf = NULL;

	return 0;

}



static int ipv6_route_yield(struct fib6_walker_t *w)

{

	struct ipv6_route_iter *iter = w->args;



	if (!iter->skip)

		return 1;



	do {

		iter->w.leaf = iter->w.leaf->dst.rt6_next;

		iter->skip--;

		if (!iter->skip && iter->w.leaf)

			return 1;

	} while (iter->w.leaf);



	return 0;

}



static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter)

{

	memset(&iter->w, 0, sizeof(iter->w));

	iter->w.func = ipv6_route_yield;

	iter->w.root = &iter->tbl->tb6_root;

	iter->w.state = FWS_INIT;

	iter->w.node = iter->w.root;

	iter->w.args = iter;

	INIT_LIST_HEAD(&iter->w.lh);

	fib6_walker_link(&iter->w);

}



static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,

						    struct net *net)

{

	unsigned int h;

	struct hlist_node *node;



	if (tbl) {

		h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;

		node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));

	} else {

		h = 0;

		node = NULL;

	}



	while (!node && h < FIB6_TABLE_HASHSZ) {

		node = rcu_dereference_bh(

			hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));

	}

	return hlist_entry_safe(node, struct fib6_table, tb6_hlist);

}



static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)

{

	int r;

	struct rt6_info *n;

	struct net *net = seq_file_net(seq);

	struct ipv6_route_iter *iter = seq->private;



	if (!v)

		goto iter_table;



	n = ((struct rt6_info *)v)->dst.rt6_next;

	if (n) {

		++*pos;

		return n;

	}



iter_table:

	read_lock(&iter->tbl->tb6_lock);

	r = fib6_walk_continue(&iter->w);

	read_unlock(&iter->tbl->tb6_lock);

	if (r > 0) {

		if (v)

			++*pos;

		return iter->w.leaf;

	} else if (r < 0) {

		fib6_walker_unlink(&iter->w);

		return NULL;

	}

	fib6_walker_unlink(&iter->w);



	iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);

	if (!iter->tbl)

		return NULL;



	ipv6_route_seq_setup_walk(iter);

	goto iter_table;

}



static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)

	__acquires(RCU_BH)

{

	struct net *net = seq_file_net(seq);

	struct ipv6_route_iter *iter = seq->private;



	rcu_read_lock_bh();

	iter->tbl = ipv6_route_seq_next_table(NULL, net);

	iter->skip = *pos;



	if (iter->tbl) {

		ipv6_route_seq_setup_walk(iter);

		return ipv6_route_seq_next(seq, NULL, pos);

	} else {

		return NULL;

	}

}



static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)

{

	struct fib6_walker_t *w = &iter->w;

	return w->node && !(w->state == FWS_U && w->node == w->root);

}



static void ipv6_route_seq_stop(struct seq_file *seq, void *v)

	__releases(RCU_BH)

{

	struct ipv6_route_iter *iter = seq->private;



	if (ipv6_route_iter_active(iter))

		fib6_walker_unlink(&iter->w);



	rcu_read_unlock_bh();

}



static const struct seq_operations ipv6_route_seq_ops = {

	.start	= ipv6_route_seq_start,

	.next	= ipv6_route_seq_next,

	.stop	= ipv6_route_seq_stop,

	.show	= ipv6_route_seq_show

};



int ipv6_route_open(struct inode *inode, struct file *file)

{

	return seq_open_net(inode, file, &ipv6_route_seq_ops,

			    sizeof(struct ipv6_route_iter));

}



#endif /* CONFIG_PROC_FS */

net/ipv6/route.c

+1 −45
Original line number Diff line number Diff line
@@ -2800,56 +2800,12 @@ static int ip6_route_dev_notify(struct notifier_block *this, 


#ifdef CONFIG_PROC_FS



struct rt6_proc_arg

{

	char *buffer;

	int offset;

	int length;

	int skip;

	int len;

};



static int rt6_info_route(struct rt6_info *rt, void *p_arg)

{

	struct seq_file *m = p_arg;



	seq_printf(m, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);



#ifdef CONFIG_IPV6_SUBTREES

	seq_printf(m, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);

#else

	seq_puts(m, "00000000000000000000000000000000 00 ");

#endif

	if (rt->rt6i_flags & RTF_GATEWAY) {

		seq_printf(m, "%pi6", &rt->rt6i_gateway);

	} else {

		seq_puts(m, "00000000000000000000000000000000");

	}

	seq_printf(m, " %08x %08x %08x %08x %8s\n",

		   rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),

		   rt->dst.__use, rt->rt6i_flags,

		   rt->dst.dev ? rt->dst.dev->name : "");

	return 0;

}



static int ipv6_route_show(struct seq_file *m, void *v)

{

	struct net *net = (struct net *)m->private;

	fib6_clean_all_ro(net, rt6_info_route, 0, m);

	return 0;

}



static int ipv6_route_open(struct inode *inode, struct file *file)

{

	return single_open_net(inode, file, ipv6_route_show);

}



static const struct file_operations ipv6_route_proc_fops = {

	.owner		= THIS_MODULE,

	.open		= ipv6_route_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release_net,

	.release	= seq_release_net,

};



static int rt6_stats_seq_show(struct seq_file *seq, void *v)

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