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/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 43a124f..5463969 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -80,6 +80,7 @@
struct mutex *cb_mutex;
struct mutex cb_def_mutex;
void (*netlink_rcv)(struct sk_buff *skb);
+ void (*netlink_bind)(int group);
struct module *module;
};
@@ -124,6 +125,7 @@
unsigned int groups;
struct mutex *cb_mutex;
struct module *module;
+ void (*bind)(int group);
int registered;
};
@@ -444,6 +446,7 @@
struct module *module = NULL;
struct mutex *cb_mutex;
struct netlink_sock *nlk;
+ void (*bind)(int group);
int err = 0;
sock->state = SS_UNCONNECTED;
@@ -468,6 +471,7 @@
else
err = -EPROTONOSUPPORT;
cb_mutex = nl_table[protocol].cb_mutex;
+ bind = nl_table[protocol].bind;
netlink_unlock_table();
if (err < 0)
@@ -483,6 +487,7 @@
nlk = nlk_sk(sock->sk);
nlk->module = module;
+ nlk->netlink_bind = bind;
out:
return err;
@@ -683,6 +688,15 @@
netlink_update_listeners(sk);
netlink_table_ungrab();
+ if (nlk->netlink_bind && nlk->groups[0]) {
+ int i;
+
+ for (i=0; i<nlk->ngroups; i++) {
+ if (test_bit(i, nlk->groups))
+ nlk->netlink_bind(i);
+ }
+ }
+
return 0;
}
@@ -1239,6 +1253,10 @@
netlink_update_socket_mc(nlk, val,
optname == NETLINK_ADD_MEMBERSHIP);
netlink_table_ungrab();
+
+ if (nlk->netlink_bind)
+ nlk->netlink_bind(val);
+
err = 0;
break;
}
@@ -1559,6 +1577,7 @@
rcu_assign_pointer(nl_table[unit].listeners, listeners);
nl_table[unit].cb_mutex = cb_mutex;
nl_table[unit].module = module;
+ nl_table[unit].bind = cfg ? cfg->bind : NULL;
nl_table[unit].registered = 1;
} else {
kfree(listeners);