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>

10 files changed, 59 insertions, 27 deletions

diff --git a/net/bridge/netfilter/ebt_ulog.c b/net/bridge/netfilter/ebt_ulog.c
index 1bd1732..374bdcd 100644
--- a/net/bridge/netfilter/ebt_ulog.c
+++ b/net/bridge/netfilter/ebt_ulog.c
@@ -282,6 +282,9 @@ static int __init ebt_ulog_init(void)
 {
 	int ret;
 	int i;
+	struct netlink_kernel_cfg cfg = {
+		.groups	= EBT_ULOG_MAXNLGROUPS,
+	};
 
 	if (nlbufsiz >= 128*1024) {
 		pr_warning("Netlink buffer has to be <= 128kB,"
@@ -296,8 +299,7 @@ static int __init ebt_ulog_init(void)
 	}
 
 	ebtulognl = netlink_kernel_create(&init_net, NETLINK_NFLOG,
-					  EBT_ULOG_MAXNLGROUPS, NULL, NULL,
-					  THIS_MODULE);
+					  THIS_MODULE, &cfg);
 	if (!ebtulognl)
 		ret = -ENOMEM;
 	else if ((ret = xt_register_target(&ebt_ulog_tg_reg)) != 0)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index bc8a1cd..2b325c3 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2353,8 +2353,13 @@ static struct notifier_block rtnetlink_dev_notifier = {
 static int __net_init rtnetlink_net_init(struct net *net)
 {
 	struct sock *sk;
-	sk = netlink_kernel_create(net, NETLINK_ROUTE, RTNLGRP_MAX,
-				   rtnetlink_rcv, &rtnl_mutex, THIS_MODULE);
+	struct netlink_kernel_cfg cfg = {
+		.groups		= RTNLGRP_MAX,
+		.input		= rtnetlink_rcv,
+		.cb_mutex	= &rtnl_mutex,
+	};
+
+	sk = netlink_kernel_create(net, NETLINK_ROUTE, THIS_MODULE, &cfg);
 	if (!sk)
 		return -ENOMEM;
 	net->rtnl = sk;
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index ff2967a..07a29eb 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -171,8 +171,12 @@ EXPORT_SYMBOL_GPL(sock_diag_nlsk);
 
 static int __init sock_diag_init(void)
 {
-	sock_diag_nlsk = netlink_kernel_create(&init_net, NETLINK_SOCK_DIAG, 0,
-					sock_diag_rcv, NULL, THIS_MODULE);
+	struct netlink_kernel_cfg cfg = {
+		.input	= sock_diag_rcv,
+	};
+
+	sock_diag_nlsk = netlink_kernel_create(&init_net, NETLINK_SOCK_DIAG,
+					       THIS_MODULE, &cfg);
 	return sock_diag_nlsk == NULL ? -ENOMEM : 0;
 }
 
diff --git a/net/decnet/netfilter/dn_rtmsg.c b/net/decnet/netfilter/dn_rtmsg.c
index b8f7f5b..11db0ec 100644
--- a/net/decnet/netfilter/dn_rtmsg.c
+++ b/net/decnet/netfilter/dn_rtmsg.c
@@ -125,11 +125,13 @@ static struct nf_hook_ops dnrmg_ops __read_mostly = {
 static int __init dn_rtmsg_init(void)
 {
 	int rv = 0;
+	struct netlink_kernel_cfg cfg = {
+		.groups	= DNRNG_NLGRP_MAX,
+		.input	= dnrmg_receive_user_skb,
+	};
 
 	dnrmg = netlink_kernel_create(&init_net,
-				      NETLINK_DNRTMSG, DNRNG_NLGRP_MAX,
-				      dnrmg_receive_user_skb,
-				      NULL, THIS_MODULE);
+				      NETLINK_DNRTMSG, THIS_MODULE, &cfg);
 	if (dnrmg == NULL) {
 		printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket");
 		return -ENOMEM;
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index ae528d1..3e11ea2 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 99b3f53..1109f7f 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;
 
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 3e797d1..700e461 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -203,9 +203,12 @@ static void nfnetlink_rcv(struct sk_buff *skb)
 static int __net_init nfnetlink_net_init(struct net *net)
 {
 	struct sock *nfnl;
+	struct netlink_kernel_cfg cfg = {
+		.groups	= NFNLGRP_MAX,
+		.input	= nfnetlink_rcv,
+	};
 
-	nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, NFNLGRP_MAX,
-				     nfnetlink_rcv, NULL, THIS_MODULE);
+	nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, THIS_MODULE, &cfg);
 	if (!nfnl)
 		return -ENOMEM;
 	net->nfnl_stash = nfnl;
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index b3025a6..43a124f 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1503,14 +1503,16 @@ static void netlink_data_ready(struct sock *sk, int len)
  */
 
 struct sock *
-netlink_kernel_create(struct net *net, int unit, unsigned int groups,
-		      void (*input)(struct sk_buff *skb),
-		      struct mutex *cb_mutex, struct module *module)
+netlink_kernel_create(struct net *net, int unit,
+		      struct module *module,
+		      struct netlink_kernel_cfg *cfg)
 {
 	struct socket *sock;
 	struct sock *sk;
 	struct netlink_sock *nlk;
 	struct listeners *listeners = NULL;
+	struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
+	unsigned int groups;
 
 	BUG_ON(!nl_table);
 
@@ -1532,16 +1534,18 @@ netlink_kernel_create(struct net *net, int unit, unsigned int groups,
 	sk = sock->sk;
 	sk_change_net(sk, net);
 
-	if (groups < 32)
+	if (!cfg || cfg->groups < 32)
 		groups = 32;
+	else
+		groups = cfg->groups;
 
 	listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
 	if (!listeners)
 		goto out_sock_release;
 
 	sk->sk_data_ready = netlink_data_ready;
-	if (input)
-		nlk_sk(sk)->netlink_rcv = input;
+	if (cfg && cfg->input)
+		nlk_sk(sk)->netlink_rcv = cfg->input;
 
 	if (netlink_insert(sk, net, 0))
 		goto out_sock_release;
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 2cc7c1e..32761b5 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -915,10 +915,14 @@ static struct genl_multicast_group notify_grp = {
 
 static int __net_init genl_pernet_init(struct net *net)
 {
+	struct netlink_kernel_cfg cfg = {
+		.input		= genl_rcv,
+		.cb_mutex	= &genl_mutex,
+	};
+
 	/* we'll bump the group number right afterwards */
-	net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
-					       genl_rcv, &genl_mutex,
-					       THIS_MODULE);
+	net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC,
+					       THIS_MODULE, &cfg);
 
 	if (!net->genl_sock && net_eq(net, &init_net))
 		panic("GENL: Cannot initialize generic netlink\n");
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 5407627..e75d8e4 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2959,9 +2959,12 @@ static struct xfrm_mgr netlink_mgr = {
 static int __net_init xfrm_user_net_init(struct net *net)
 {
 	struct sock *nlsk;
+	struct netlink_kernel_cfg cfg = {
+		.groups	= XFRMNLGRP_MAX,
+		.input	= xfrm_netlink_rcv,
+	};
 
-	nlsk = netlink_kernel_create(net, NETLINK_XFRM, XFRMNLGRP_MAX,
-				     xfrm_netlink_rcv, NULL, THIS_MODULE);
+	nlsk = netlink_kernel_create(net, NETLINK_XFRM, THIS_MODULE, &cfg);
 	if (nlsk == NULL)
 		return -ENOMEM;
 	net->xfrm.nlsk_stash = nlsk; /* Don't set to NULL */