netlink: add netlink_kernel_cfg parameter to netlink_kernel_create

This patch adds the following structure:

struct netlink_kernel_cfg {
        unsigned int    groups;
        void            (*input)(struct sk_buff *skb);
        struct mutex    *cb_mutex;
};

That can be passed to netlink_kernel_create to set optional configurations
for netlink kernel sockets.

I've populated this structure by looking for NULL and zero parameters at the
existing code. The remaining parameters that always need to be set are still
left in the original interface.

That includes optional parameters for the netlink socket creation. This allows
easy extensibility of this interface in the future.

This patch also adapts all callers to use this new interface.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 10 insertions, 5 deletions

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index ae528d1b293a..3e11ea225dad 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -976,8 +976,11 @@ static void nl_fib_input(struct sk_buff *skb)
 static int __net_init nl_fib_lookup_init(struct net *net)
 {
         struct sock *sk;
-        sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, 0,
-                                   nl_fib_input, NULL, THIS_MODULE);
+        struct netlink_kernel_cfg cfg = {
+                .input  = nl_fib_input,
+        };
+
+        sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, THIS_MODULE, &cfg);
         if (sk == NULL)
                 return -EAFNOSUPPORT;
         net->ipv4.fibnl = sk;
diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c
index 99b3f53f16a7..1109f7f6c254 100644
--- a/net/ipv4/netfilter/ipt_ULOG.c
+++ b/net/ipv4/netfilter/ipt_ULOG.c
@@ -381,6 +381,9 @@ static struct nf_logger ipt_ulog_logger __read_mostly = {
 static int __init ulog_tg_init(void)
 {
         int ret, i;
+        struct netlink_kernel_cfg cfg = {
+                .groups = ULOG_MAXNLGROUPS,
+        };
 
         pr_debug("init module\n");
 
@@ -393,9 +396,8 @@ static int __init ulog_tg_init(void)
         for (i = 0; i < ULOG_MAXNLGROUPS; i++)
                 setup_timer(&ulog_buffers[i].timer, ulog_timer, i);
 
-        nflognl = netlink_kernel_create(&init_net,
-                                        NETLINK_NFLOG, ULOG_MAXNLGROUPS, NULL,
-                                        NULL, THIS_MODULE);
+        nflognl = netlink_kernel_create(&init_net, NETLINK_NFLOG,
+                                        THIS_MODULE, &cfg);
         if (!nflognl)
                 return -ENOMEM;