[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, 3 insertions, 3 deletions

diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index 64536a3ef2f6..2f5a52453834 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -569,7 +569,7 @@ ipq_rcv_nl_event(struct notifier_block *this,
         if (event == NETLINK_URELEASE &&
             n->protocol == NETLINK_IP6_FW && n->pid) {
                 write_lock_bh(&queue_lock);
-                if (n->pid == peer_pid)
+                if ((n->net == &init_net) && (n->pid == peer_pid))
                         __ipq_reset();
                 write_unlock_bh(&queue_lock);
         }
@@ -661,8 +661,8 @@ static int __init ip6_queue_init(void)
         struct proc_dir_entry *proc;
 
         netlink_register_notifier(&ipq_nl_notifier);
-        ipqnl = netlink_kernel_create(NETLINK_IP6_FW, 0, ipq_rcv_sk, NULL,
-                                      THIS_MODULE);
+        ipqnl = netlink_kernel_create(&init_net, NETLINK_IP6_FW, 0, ipq_rcv_sk,
+                                        NULL, THIS_MODULE);
         if (ipqnl == NULL) {
                 printk(KERN_ERR "ip6_queue: failed to create netlink socket\n");
                 goto cleanup_netlink_notifier;