Commit 78222bac authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso
Browse files

netfilter: cttimeout: decouple unlink and free on netns destruction 



Make it so netns pre_exit unlinks the objects from the pernet list, so
they cannot be found anymore.

netns core issues a synchronize_rcu() before calling the exit hooks so
any the time the exit hooks run unconfirmed nf_conn entries have been
free'd or they have been committed to the hashtable.

The exit hook still tags unconfirmed entries as dying, this can
now be removed in a followup change.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 1397af5b

include/net/netfilter/nf_conntrack_timeout.h

+0 −8
Original line number Diff line number Diff line
@@ -17,14 +17,6 @@ struct nf_ct_timeout { 
	char			data[];

};



struct ctnl_timeout {

	struct list_head	head;

	struct rcu_head		rcu_head;

	refcount_t		refcnt;

	char			name[CTNL_TIMEOUT_NAME_MAX];

	struct nf_ct_timeout	timeout;

};



struct nf_conn_timeout {

	struct nf_ct_timeout __rcu *timeout;

};

net/netfilter/nfnetlink_cttimeout.c

+28 −2
Original line number Diff line number Diff line
@@ -33,8 +33,19 @@ 


static unsigned int nfct_timeout_id __read_mostly;



struct ctnl_timeout {

	struct list_head	head;

	struct rcu_head		rcu_head;

	refcount_t		refcnt;

	char			name[CTNL_TIMEOUT_NAME_MAX];

	struct nf_ct_timeout	timeout;



	struct list_head	free_head;

};



struct nfct_timeout_pernet {

	struct list_head	nfct_timeout_list;

	struct list_head	nfct_timeout_freelist;

};



MODULE_LICENSE("GPL");
@@ -574,10 +585,24 @@ static int __net_init cttimeout_net_init(struct net *net) 
	struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net);



	INIT_LIST_HEAD(&pernet->nfct_timeout_list);

	INIT_LIST_HEAD(&pernet->nfct_timeout_freelist);



	return 0;

}



static void __net_exit cttimeout_net_pre_exit(struct net *net)

{

	struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net);

	struct ctnl_timeout *cur, *tmp;



	list_for_each_entry_safe(cur, tmp, &pernet->nfct_timeout_list, head) {

		list_del_rcu(&cur->head);

		list_add(&cur->free_head, &pernet->nfct_timeout_freelist);

	}



	/* core calls synchronize_rcu() after this */

}



static void __net_exit cttimeout_net_exit(struct net *net)

{

	struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net);
@@ -586,8 +611,8 @@ static void __net_exit cttimeout_net_exit(struct net *net) 
	nf_ct_unconfirmed_destroy(net);

	nf_ct_untimeout(net, NULL);



	list_for_each_entry_safe(cur, tmp, &pernet->nfct_timeout_list, head) {

		list_del_rcu(&cur->head);

	list_for_each_entry_safe(cur, tmp, &pernet->nfct_timeout_freelist, head) {

		list_del(&cur->free_head);



		if (refcount_dec_and_test(&cur->refcnt))

			kfree_rcu(cur, rcu_head);
@@ -596,6 +621,7 @@ static void __net_exit cttimeout_net_exit(struct net *net) 


static struct pernet_operations cttimeout_ops = {

	.init	= cttimeout_net_init,

	.pre_exit = cttimeout_net_pre_exit,

	.exit	= cttimeout_net_exit,

	.id     = &nfct_timeout_id,

	.size   = sizeof(struct nfct_timeout_pernet),