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: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index d87a939..49a04fa 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -105,16 +105,14 @@
struct nf_conntrack_l3proto *l3proto;
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);
- nf_ct_l3proto_put(l3proto);
if (unlikely(ret < 0))
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);
- nf_ct_l4proto_put(l4proto);
return ret;
}
@@ -151,11 +149,9 @@
struct nlattr *nest_proto;
int ret;
- l4proto = nf_ct_l4proto_find_get(nf_ct_l3num(ct), nf_ct_protonum(ct));
- if (!l4proto->to_nlattr) {
- nf_ct_l4proto_put(l4proto);
+ l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
+ if (!l4proto->to_nlattr)
return 0;
- }
nest_proto = nla_nest_start(skb, CTA_PROTOINFO | NLA_F_NESTED);
if (!nest_proto)
@@ -163,14 +159,11 @@
ret = l4proto->to_nlattr(skb, nest_proto, ct);
- nf_ct_l4proto_put(l4proto);
-
nla_nest_end(skb, nest_proto);
return ret;
nla_put_failure:
- nf_ct_l4proto_put(l4proto);
return -1;
}
@@ -184,7 +177,6 @@
if (!help)
return 0;
- rcu_read_lock();
helper = rcu_dereference(help->helper);
if (!helper)
goto out;
@@ -199,11 +191,9 @@
nla_nest_end(skb, nest_helper);
out:
- rcu_read_unlock();
return 0;
nla_put_failure:
- rcu_read_unlock();
return -1;
}
@@ -461,6 +451,7 @@
nfmsg->version = NFNETLINK_V0;
nfmsg->res_id = 0;
+ rcu_read_lock();
nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED);
if (!nest_parms)
goto nla_put_failure;
@@ -517,13 +508,15 @@
&& ctnetlink_dump_mark(skb, ct) < 0)
goto nla_put_failure;
#endif
+ rcu_read_unlock();
nlh->nlmsg_len = skb->tail - b;
nfnetlink_send(skb, 0, group, 0);
return NOTIFY_DONE;
-nlmsg_failure:
nla_put_failure:
+ rcu_read_unlock();
+nlmsg_failure:
kfree_skb(skb);
return NOTIFY_DONE;
}
@@ -795,8 +788,10 @@
return -ENOMEM;
}
+ rcu_read_lock();
err = ctnetlink_fill_info(skb2, NETLINK_CB(skb).pid, nlh->nlmsg_seq,
IPCTNL_MSG_CT_NEW, 1, ct);
+ rcu_read_unlock();
nf_ct_put(ct);
if (err <= 0)
goto free;
@@ -1292,16 +1287,14 @@
if (!nest_parms)
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);
- nf_ct_l3proto_put(l3proto);
if (unlikely(ret < 0))
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);
- nf_ct_l4proto_put(l4proto);
if (unlikely(ret < 0))
goto nla_put_failure;
@@ -1408,15 +1401,18 @@
nfmsg->version = NFNETLINK_V0;
nfmsg->res_id = 0;
+ rcu_read_lock();
if (ctnetlink_exp_dump_expect(skb, exp) < 0)
goto nla_put_failure;
+ rcu_read_unlock();
nlh->nlmsg_len = skb->tail - b;
nfnetlink_send(skb, 0, NFNLGRP_CONNTRACK_EXP_NEW, 0);
return NOTIFY_DONE;
-nlmsg_failure:
nla_put_failure:
+ rcu_read_unlock();
+nlmsg_failure:
kfree_skb(skb);
return NOTIFY_DONE;
}
@@ -1520,9 +1516,11 @@
if (!skb2)
goto out;
+ rcu_read_lock();
err = ctnetlink_exp_fill_info(skb2, NETLINK_CB(skb).pid,
nlh->nlmsg_seq, IPCTNL_MSG_EXP_NEW,
1, exp);
+ rcu_read_unlock();
if (err <= 0)
goto free;