netfilter: nfnetlink_osf: extract nfnetlink_subsystem code from xt_osf.c

Move nfnetlink osf subsystem from xt_osf.c to standalone module so we can
reuse it from the new nft_ost extension.

Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 3 insertions, 146 deletions

diff --git a/net/netfilter/xt_osf.c b/net/netfilter/xt_osf.c
index 9cfef73b4107..bf7bba80e24c 100644
--- a/net/netfilter/xt_osf.c
+++ b/net/netfilter/xt_osf.c
@@ -37,118 +37,6 @@
 #include <net/netfilter/nf_log.h>
 #include <linux/netfilter/xt_osf.h>
 
-/*
- * Indexed by dont-fragment bit.
- * It is the only constant value in the fingerprint.
- */
-static struct list_head xt_osf_fingers[2];
-
-static const struct nla_policy xt_osf_policy[OSF_ATTR_MAX + 1] = {
-	[OSF_ATTR_FINGER]	= { .len = sizeof(struct xt_osf_user_finger) },
-};
-
-static int xt_osf_add_callback(struct net *net, struct sock *ctnl,
-			       struct sk_buff *skb, const struct nlmsghdr *nlh,
-			       const struct nlattr * const osf_attrs[],
-			       struct netlink_ext_ack *extack)
-{
-	struct xt_osf_user_finger *f;
-	struct xt_osf_finger *kf = NULL, *sf;
-	int err = 0;
-
-	if (!capable(CAP_NET_ADMIN))
-		return -EPERM;
-
-	if (!osf_attrs[OSF_ATTR_FINGER])
-		return -EINVAL;
-
-	if (!(nlh->nlmsg_flags & NLM_F_CREATE))
-		return -EINVAL;
-
-	f = nla_data(osf_attrs[OSF_ATTR_FINGER]);
-
-	kf = kmalloc(sizeof(struct xt_osf_finger), GFP_KERNEL);
-	if (!kf)
-		return -ENOMEM;
-
-	memcpy(&kf->finger, f, sizeof(struct xt_osf_user_finger));
-
-	list_for_each_entry(sf, &xt_osf_fingers[!!f->df], finger_entry) {
-		if (memcmp(&sf->finger, f, sizeof(struct xt_osf_user_finger)))
-			continue;
-
-		kfree(kf);
-		kf = NULL;
-
-		if (nlh->nlmsg_flags & NLM_F_EXCL)
-			err = -EEXIST;
-		break;
-	}
-
-	/*
-	 * We are protected by nfnl mutex.
-	 */
-	if (kf)
-		list_add_tail_rcu(&kf->finger_entry, &xt_osf_fingers[!!f->df]);
-
-	return err;
-}
-
-static int xt_osf_remove_callback(struct net *net, struct sock *ctnl,
-				  struct sk_buff *skb,
-				  const struct nlmsghdr *nlh,
-				  const struct nlattr * const osf_attrs[],
-				  struct netlink_ext_ack *extack)
-{
-	struct xt_osf_user_finger *f;
-	struct xt_osf_finger *sf;
-	int err = -ENOENT;
-
-	if (!capable(CAP_NET_ADMIN))
-		return -EPERM;
-
-	if (!osf_attrs[OSF_ATTR_FINGER])
-		return -EINVAL;
-
-	f = nla_data(osf_attrs[OSF_ATTR_FINGER]);
-
-	list_for_each_entry(sf, &xt_osf_fingers[!!f->df], finger_entry) {
-		if (memcmp(&sf->finger, f, sizeof(struct xt_osf_user_finger)))
-			continue;
-
-		/*
-		 * We are protected by nfnl mutex.
-		 */
-		list_del_rcu(&sf->finger_entry);
-		kfree_rcu(sf, rcu_head);
-
-		err = 0;
-		break;
-	}
-
-	return err;
-}
-
-static const struct nfnl_callback xt_osf_nfnetlink_callbacks[OSF_MSG_MAX] = {
-	[OSF_MSG_ADD]	= {
-		.call		= xt_osf_add_callback,
-		.attr_count	= OSF_ATTR_MAX,
-		.policy		= xt_osf_policy,
-	},
-	[OSF_MSG_REMOVE]	= {
-		.call		= xt_osf_remove_callback,
-		.attr_count	= OSF_ATTR_MAX,
-		.policy		= xt_osf_policy,
-	},
-};
-
-static const struct nfnetlink_subsystem xt_osf_nfnetlink = {
-	.name			= "osf",
-	.subsys_id		= NFNL_SUBSYS_OSF,
-	.cb_count		= OSF_MSG_MAX,
-	.cb			= xt_osf_nfnetlink_callbacks,
-};
-
 static bool
 xt_osf_match_packet(const struct sk_buff *skb, struct xt_action_param *p)
 {
@@ -159,7 +47,7 @@ xt_osf_match_packet(const struct sk_buff *skb, struct xt_action_param *p)
 		return false;
 
 	return nf_osf_match(skb, xt_family(p), xt_hooknum(p), xt_in(p),
-			    xt_out(p), info, net, xt_osf_fingers);
+			    xt_out(p), info, net, nf_osf_fingers);
 }
 
 static struct xt_match xt_osf_match = {
@@ -177,52 +65,21 @@ static struct xt_match xt_osf_match = {
 
 static int __init xt_osf_init(void)
 {
-	int err = -EINVAL;
-	int i;
-
-	for (i=0; i<ARRAY_SIZE(xt_osf_fingers); ++i)
-		INIT_LIST_HEAD(&xt_osf_fingers[i]);
-
-	err = nfnetlink_subsys_register(&xt_osf_nfnetlink);
-	if (err < 0) {
-		pr_err("Failed to register OSF nsfnetlink helper (%d)\n", err);
-		goto err_out_exit;
-	}
+	int err;
 
 	err = xt_register_match(&xt_osf_match);
 	if (err) {
 		pr_err("Failed to register OS fingerprint "
 		       "matching module (%d)\n", err);
-		goto err_out_remove;
+		return err;
 	}
 
 	return 0;
-
-err_out_remove:
-	nfnetlink_subsys_unregister(&xt_osf_nfnetlink);
-err_out_exit:
-	return err;
 }
 
 static void __exit xt_osf_fini(void)
 {
-	struct xt_osf_finger *f;
-	int i;
-
-	nfnetlink_subsys_unregister(&xt_osf_nfnetlink);
 	xt_unregister_match(&xt_osf_match);
-
-	rcu_read_lock();
-	for (i=0; i<ARRAY_SIZE(xt_osf_fingers); ++i) {
-
-		list_for_each_entry_rcu(f, &xt_osf_fingers[i], finger_entry) {
-			list_del_rcu(&f->finger_entry);
-			kfree_rcu(f, rcu_head);
-		}
-	}
-	rcu_read_unlock();
-
-	rcu_barrier();
 }
 
 module_init(xt_osf_init);