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authorPablo Neira Ayuso <pablo@netfilter.org>2012-06-29 06:15:22 +0000
committerDavid S. Miller <davem@davemloft.net>2012-06-29 16:46:06 -0700
commit03292745b02d1166e2a215504407e096b8427be5 (patch)
tree2251b4bed9969a6c8a02a322927a74621b29155c
parenta31f2d17b331db970259e875b7223d3aba7e3821 (diff)
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>
-rw-r--r--include/linux/netlink.h1
-rw-r--r--net/netfilter/nfnetlink.c29
-rw-r--r--net/netlink/af_netlink.c19
3 files changed, 49 insertions, 0 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 6085e4919cb3..f74dd133788f 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -179,6 +179,7 @@ struct netlink_kernel_cfg {
unsigned int groups;
void (*input)(struct sk_buff *skb);
struct mutex *cb_mutex;
+ void (*bind)(int group);
};
extern struct sock *netlink_kernel_create(struct net *net, int unit,
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 700e4616a098..5a2132b97fe9 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -39,6 +39,15 @@ static char __initdata nfversion[] = "0.30";
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 @@ static void nfnetlink_rcv(struct sk_buff *skb)
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);
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 43a124feaad8..5463969da45b 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -80,6 +80,7 @@ struct netlink_sock {
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 @@ struct netlink_table {
unsigned int groups;
struct mutex *cb_mutex;
struct module *module;
+ void (*bind)(int group);
int registered;
};
@@ -444,6 +446,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
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 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
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 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
nlk = nlk_sk(sock->sk);
nlk->module = module;
+ nlk->netlink_bind = bind;
out:
return err;
@@ -683,6 +688,15 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
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 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname,
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 @@ netlink_kernel_create(struct net *net, int unit,
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);

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