[NET]: Support multiple network namespaces with netlink

Each netlink socket will live in exactly one network namespace,
this includes the controlling kernel sockets.

This patch updates all of the existing netlink protocols
to only support the initial network namespace.  Request
by clients in other namespaces will get -ECONREFUSED.
As they would if the kernel did not have the support for
that netlink protocol compiled in.

As each netlink protocol is updated to be multiple network
namespace safe it can register multiple kernel sockets
to acquire a presence in the rest of the network namespaces.

The implementation in af_netlink is a simple filter implementation
at hash table insertion and hash table look up time.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 83d8239f0cce..d2843ae4a83a 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -27,6 +27,8 @@
 
 #define MAX_LINKS 32            
 
+struct net;
+
 struct sockaddr_nl
 {
         sa_family_t     nl_family;      /* AF_NETLINK   */
@@ -157,7 +159,8 @@ struct netlink_skb_parms
 #define NETLINK_CREDS(skb)      (&NETLINK_CB((skb)).creds)
 
 
-extern struct sock *netlink_kernel_create(int unit, unsigned int groups,
+extern struct sock *netlink_kernel_create(struct net *net,
+                                          int unit,unsigned int groups,
                                           void (*input)(struct sock *sk, int len),
                                           struct mutex *cb_mutex,
                                           struct module *module);
@@ -206,6 +209,7 @@ struct netlink_callback
 
 struct netlink_notify
 {
+        struct net *net;
         int pid;
         int protocol;
 };