net: make sock diag per-namespace

Before this patch sock_diag works for init_net only and dumps
information about sockets from all namespaces.

This patch expands sock_diag for all name-spaces.
It creates a netlink kernel socket for each netns and filters
data during dumping.

v2: filter accoding with netns in all places
    remove an unused variable.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Pavel Emelyanov <xemul@parallels.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 7 deletions

diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 07a29eb34a41..9d8755e4a7a5 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -166,23 +166,36 @@ static void sock_diag_rcv(struct sk_buff *skb)
         mutex_unlock(&sock_diag_mutex);
 }
 
-struct sock *sock_diag_nlsk;
-EXPORT_SYMBOL_GPL(sock_diag_nlsk);
-
-static int __init sock_diag_init(void)
+static int __net_init diag_net_init(struct net *net)
 {
         struct netlink_kernel_cfg cfg = {
                 .input  = sock_diag_rcv,
         };
 
-        sock_diag_nlsk = netlink_kernel_create(&init_net, NETLINK_SOCK_DIAG,
+        net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG,
                                                THIS_MODULE, &cfg);
-        return sock_diag_nlsk == NULL ? -ENOMEM : 0;
+        return net->diag_nlsk == NULL ? -ENOMEM : 0;
+}
+
+static void __net_exit diag_net_exit(struct net *net)
+{
+        netlink_kernel_release(net->diag_nlsk);
+        net->diag_nlsk = NULL;
+}
+
+static struct pernet_operations diag_net_ops = {
+        .init = diag_net_init,
+        .exit = diag_net_exit,
+};
+
+static int __init sock_diag_init(void)
+{
+        return register_pernet_subsys(&diag_net_ops);
 }
 
 static void __exit sock_diag_exit(void)
 {
-        netlink_kernel_release(sock_diag_nlsk);
+        unregister_pernet_subsys(&diag_net_ops);
 }
 
 module_init(sock_diag_init);