netlink: add nlk->netlink_bind hook for module auto-loading
This patch adds a hook in the binding path of netlink.
This is used by ctnetlink to allow module autoloading for the case
in which one user executes:
conntrack -E
So far, this resulted in nfnetlink loaded, but not
nf_conntrack_netlink.
I have received in the past many complains on this behaviour.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 700e461..5a2132b 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -39,6 +39,15 @@
static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT];
static DEFINE_MUTEX(nfnl_mutex);
+static const int nfnl_group2type[NFNLGRP_MAX+1] = {
+ [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK,
+ [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK,
+ [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK,
+ [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP,
+ [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP,
+ [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
+};
+
void nfnl_lock(void)
{
mutex_lock(&nfnl_mutex);
@@ -200,12 +209,32 @@
netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
}
+#ifdef CONFIG_MODULES
+static void nfnetlink_bind(int group)
+{
+ const struct nfnetlink_subsystem *ss;
+ int type = nfnl_group2type[group];
+
+ rcu_read_lock();
+ ss = nfnetlink_get_subsys(type);
+ if (!ss) {
+ rcu_read_unlock();
+ request_module("nfnetlink-subsys-%d", type);
+ return;
+ }
+ rcu_read_unlock();
+}
+#endif
+
static int __net_init nfnetlink_net_init(struct net *net)
{
struct sock *nfnl;
struct netlink_kernel_cfg cfg = {
.groups = NFNLGRP_MAX,
.input = nfnetlink_rcv,
+#ifdef CONFIG_MODULES
+ .bind = nfnetlink_bind,
+#endif
};
nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, THIS_MODULE, &cfg);