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Commit 528a3a6f authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso Committed by Patrick McHardy
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netfilter: ctnetlink: get rid of module refcounting in ctnetlink 



This patch replaces the unnecessary module refcounting with
the read-side locks. With this patch, all the dump and fill_info
function are called under the RCU read lock.

Based on a patch from Fabian Hugelshofer.

Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
parent bfe29677

net/netfilter/nf_conntrack_netlink.c

+18 −20
Original line number Original line Diff line number Diff line
@@ -105,16 +105,14 @@ ctnetlink_dump_tuples(struct sk_buff *skb, 
	struct nf_conntrack_l3proto *l3proto;

	struct nf_conntrack_l3proto *l3proto;

	struct nf_conntrack_l4proto *l4proto;

	struct nf_conntrack_l4proto *l4proto;





	l3proto = nf_ct_l3proto_find_get(tuple->src.l3num);

	l3proto = __nf_ct_l3proto_find(tuple->src.l3num);

	ret = ctnetlink_dump_tuples_ip(skb, tuple, l3proto);

	ret = ctnetlink_dump_tuples_ip(skb, tuple, l3proto);

	nf_ct_l3proto_put(l3proto);





	if (unlikely(ret < 0))

	if (unlikely(ret < 0))

		return ret;

		return ret;





	l4proto = nf_ct_l4proto_find_get(tuple->src.l3num, tuple->dst.protonum);

	l4proto = __nf_ct_l4proto_find(tuple->src.l3num, tuple->dst.protonum);

	ret = ctnetlink_dump_tuples_proto(skb, tuple, l4proto);

	ret = ctnetlink_dump_tuples_proto(skb, tuple, l4proto);

	nf_ct_l4proto_put(l4proto);





	return ret;

	return ret;

}

}
@@ -151,11 +149,9 @@ ctnetlink_dump_protoinfo(struct sk_buff *skb, const struct nf_conn *ct) 
	struct nlattr *nest_proto;

	struct nlattr *nest_proto;

	int ret;

	int ret;





	l4proto = nf_ct_l4proto_find_get(nf_ct_l3num(ct), nf_ct_protonum(ct));

	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));

	if (!l4proto->to_nlattr) {

	if (!l4proto->to_nlattr)

		nf_ct_l4proto_put(l4proto);

		return 0;

		return 0;

	}





	nest_proto = nla_nest_start(skb, CTA_PROTOINFO | NLA_F_NESTED);

	nest_proto = nla_nest_start(skb, CTA_PROTOINFO | NLA_F_NESTED);

	if (!nest_proto)

	if (!nest_proto)
@@ -163,14 +159,11 @@ ctnetlink_dump_protoinfo(struct sk_buff *skb, const struct nf_conn *ct) 




	ret = l4proto->to_nlattr(skb, nest_proto, ct);

	ret = l4proto->to_nlattr(skb, nest_proto, ct);





	nf_ct_l4proto_put(l4proto);



	nla_nest_end(skb, nest_proto);

	nla_nest_end(skb, nest_proto);





	return ret;

	return ret;





nla_put_failure:

nla_put_failure:

	nf_ct_l4proto_put(l4proto);

	return -1;

	return -1;

}

}
@@ -184,7 +177,6 @@ ctnetlink_dump_helpinfo(struct sk_buff *skb, const struct nf_conn *ct) 
	if (!help)

	if (!help)

		return 0;

		return 0;





	rcu_read_lock();

	helper = rcu_dereference(help->helper);

	helper = rcu_dereference(help->helper);

	if (!helper)

	if (!helper)

		goto out;

		goto out;
@@ -199,11 +191,9 @@ ctnetlink_dump_helpinfo(struct sk_buff *skb, const struct nf_conn *ct) 




	nla_nest_end(skb, nest_helper);

	nla_nest_end(skb, nest_helper);

out:

out:

	rcu_read_unlock();

	return 0;

	return 0;





nla_put_failure:

nla_put_failure:

	rcu_read_unlock();

	return -1;

	return -1;

}

}
@@ -461,6 +451,7 @@ static int ctnetlink_conntrack_event(struct notifier_block *this, 
	nfmsg->version	= NFNETLINK_V0;

	nfmsg->version	= NFNETLINK_V0;

	nfmsg->res_id	= 0;

	nfmsg->res_id	= 0;





	rcu_read_lock();

	nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED);

	nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED);

	if (!nest_parms)

	if (!nest_parms)

		goto nla_put_failure;

		goto nla_put_failure;
@@ -517,13 +508,15 @@ static int ctnetlink_conntrack_event(struct notifier_block *this, 
	    && ctnetlink_dump_mark(skb, ct) < 0)

	    && ctnetlink_dump_mark(skb, ct) < 0)

		goto nla_put_failure;

		goto nla_put_failure;

#endif

#endif

	rcu_read_unlock();





	nlh->nlmsg_len = skb->tail - b;

	nlh->nlmsg_len = skb->tail - b;

	nfnetlink_send(skb, 0, group, 0);

	nfnetlink_send(skb, 0, group, 0);

	return NOTIFY_DONE;

	return NOTIFY_DONE;





nlmsg_failure:

nla_put_failure:

nla_put_failure:

	rcu_read_unlock();

nlmsg_failure:

	kfree_skb(skb);

	kfree_skb(skb);

	return NOTIFY_DONE;

	return NOTIFY_DONE;

}

}
@@ -795,8 +788,10 @@ ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb, 
		return -ENOMEM;

		return -ENOMEM;

	}

	}





	rcu_read_lock();

	err = ctnetlink_fill_info(skb2, NETLINK_CB(skb).pid, nlh->nlmsg_seq,

	err = ctnetlink_fill_info(skb2, NETLINK_CB(skb).pid, nlh->nlmsg_seq,

				  IPCTNL_MSG_CT_NEW, 1, ct);

				  IPCTNL_MSG_CT_NEW, 1, ct);

	rcu_read_unlock();

	nf_ct_put(ct);

	nf_ct_put(ct);

	if (err <= 0)

	if (err <= 0)

		goto free;

		goto free;
@@ -1292,16 +1287,14 @@ ctnetlink_exp_dump_mask(struct sk_buff *skb, 
	if (!nest_parms)

	if (!nest_parms)

		goto nla_put_failure;

		goto nla_put_failure;





	l3proto = nf_ct_l3proto_find_get(tuple->src.l3num);

	l3proto = __nf_ct_l3proto_find(tuple->src.l3num);

	ret = ctnetlink_dump_tuples_ip(skb, &m, l3proto);

	ret = ctnetlink_dump_tuples_ip(skb, &m, l3proto);

	nf_ct_l3proto_put(l3proto);





	if (unlikely(ret < 0))

	if (unlikely(ret < 0))

		goto nla_put_failure;

		goto nla_put_failure;





	l4proto = nf_ct_l4proto_find_get(tuple->src.l3num, tuple->dst.protonum);

	l4proto = __nf_ct_l4proto_find(tuple->src.l3num, tuple->dst.protonum);

	ret = ctnetlink_dump_tuples_proto(skb, &m, l4proto);

	ret = ctnetlink_dump_tuples_proto(skb, &m, l4proto);

	nf_ct_l4proto_put(l4proto);

	if (unlikely(ret < 0))

	if (unlikely(ret < 0))

		goto nla_put_failure;

		goto nla_put_failure;
@@ -1408,15 +1401,18 @@ static int ctnetlink_expect_event(struct notifier_block *this, 
	nfmsg->version	    = NFNETLINK_V0;

	nfmsg->version	    = NFNETLINK_V0;

	nfmsg->res_id	    = 0;

	nfmsg->res_id	    = 0;





	rcu_read_lock();

	if (ctnetlink_exp_dump_expect(skb, exp) < 0)

	if (ctnetlink_exp_dump_expect(skb, exp) < 0)

		goto nla_put_failure;

		goto nla_put_failure;

	rcu_read_unlock();





	nlh->nlmsg_len = skb->tail - b;

	nlh->nlmsg_len = skb->tail - b;

	nfnetlink_send(skb, 0, NFNLGRP_CONNTRACK_EXP_NEW, 0);

	nfnetlink_send(skb, 0, NFNLGRP_CONNTRACK_EXP_NEW, 0);

	return NOTIFY_DONE;

	return NOTIFY_DONE;





nlmsg_failure:

nla_put_failure:

nla_put_failure:

	rcu_read_unlock();

nlmsg_failure:

	kfree_skb(skb);

	kfree_skb(skb);

	return NOTIFY_DONE;

	return NOTIFY_DONE;

}

}
@@ -1520,9 +1516,11 @@ ctnetlink_get_expect(struct sock *ctnl, struct sk_buff *skb, 
	if (!skb2)

	if (!skb2)

		goto out;

		goto out;





	rcu_read_lock();

	err = ctnetlink_exp_fill_info(skb2, NETLINK_CB(skb).pid,

	err = ctnetlink_exp_fill_info(skb2, NETLINK_CB(skb).pid,

				      nlh->nlmsg_seq, IPCTNL_MSG_EXP_NEW,

				      nlh->nlmsg_seq, IPCTNL_MSG_EXP_NEW,

				      1, exp);

				      1, exp);

	rcu_read_unlock();

	if (err <= 0)

	if (err <= 0)

		goto free;

		goto free;