[NETFILTER]: nf_conntrack: split out protocol handling

This patch splits out L3/L4 protocol handling into its own file
nf_conntrack_proto.c

Signed-off-by: Martin Josefsson <gandalf@wlug.westbo.se>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 225 insertions, 0 deletions

diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c
new file mode 100644
index 000000000000..24c61a384716
--- /dev/null
+++ b/net/netfilter/nf_conntrack_proto.c
@@ -0,0 +1,225 @@
+/* L3/L4 protocol support for nf_conntrack. */
+
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/types.h>
+#include <linux/netfilter.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/vmalloc.h>
+#include <linux/stddef.h>
+#include <linux/err.h>
+#include <linux/percpu.h>
+#include <linux/moduleparam.h>
+#include <linux/notifier.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_l3proto.h>
+#include <net/netfilter/nf_conntrack_protocol.h>
+#include <net/netfilter/nf_conntrack_core.h>
+
+struct nf_conntrack_protocol **nf_ct_protos[PF_MAX] __read_mostly;
+struct nf_conntrack_l3proto *nf_ct_l3protos[PF_MAX] __read_mostly;
+
+struct nf_conntrack_protocol *
+__nf_ct_proto_find(u_int16_t l3proto, u_int8_t protocol)
+{
+	if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL))
+		return &nf_conntrack_generic_protocol;
+
+	return nf_ct_protos[l3proto][protocol];
+}
+
+/* this is guaranteed to always return a valid protocol helper, since
+ * it falls back to generic_protocol */
+struct nf_conntrack_protocol *
+nf_ct_proto_find_get(u_int16_t l3proto, u_int8_t protocol)
+{
+	struct nf_conntrack_protocol *p;
+
+	preempt_disable();
+	p = __nf_ct_proto_find(l3proto, protocol);
+	if (!try_module_get(p->me))
+		p = &nf_conntrack_generic_protocol;
+	preempt_enable();
+
+	return p;
+}
+
+void nf_ct_proto_put(struct nf_conntrack_protocol *p)
+{
+	module_put(p->me);
+}
+
+struct nf_conntrack_l3proto *
+nf_ct_l3proto_find_get(u_int16_t l3proto)
+{
+	struct nf_conntrack_l3proto *p;
+
+	preempt_disable();
+	p = __nf_ct_l3proto_find(l3proto);
+	if (!try_module_get(p->me))
+		p = &nf_conntrack_generic_l3proto;
+	preempt_enable();
+
+	return p;
+}
+
+void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
+{
+	module_put(p->me);
+}
+
+int
+nf_ct_l3proto_try_module_get(unsigned short l3proto)
+{
+	int ret;
+	struct nf_conntrack_l3proto *p;
+
+retry:	p = nf_ct_l3proto_find_get(l3proto);
+	if (p == &nf_conntrack_generic_l3proto) {
+		ret = request_module("nf_conntrack-%d", l3proto);
+		if (!ret)
+			goto retry;
+
+		return -EPROTOTYPE;
+	}
+
+	return 0;
+}
+
+void nf_ct_l3proto_module_put(unsigned short l3proto)
+{
+	struct nf_conntrack_l3proto *p;
+
+	preempt_disable();
+	p = __nf_ct_l3proto_find(l3proto);
+	preempt_enable();
+
+	module_put(p->me);
+}
+
+static int kill_l3proto(struct nf_conn *i, void *data)
+{
+	return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
+			((struct nf_conntrack_l3proto *)data)->l3proto);
+}
+
+static int kill_proto(struct nf_conn *i, void *data)
+{
+	struct nf_conntrack_protocol *proto;
+	proto = (struct nf_conntrack_protocol *)data;
+	return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum ==
+			proto->proto) &&
+	       (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
+			proto->l3proto);
+}
+
+int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
+{
+	int ret = 0;
+
+	write_lock_bh(&nf_conntrack_lock);
+	if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_generic_l3proto) {
+		ret = -EBUSY;
+		goto out;
+	}
+	nf_ct_l3protos[proto->l3proto] = proto;
+out:
+	write_unlock_bh(&nf_conntrack_lock);
+
+	return ret;
+}
+
+void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
+{
+	write_lock_bh(&nf_conntrack_lock);
+	nf_ct_l3protos[proto->l3proto] = &nf_conntrack_generic_l3proto;
+	write_unlock_bh(&nf_conntrack_lock);
+
+	/* Somebody could be still looking at the proto in bh. */
+	synchronize_net();
+
+	/* Remove all contrack entries for this protocol */
+	nf_ct_iterate_cleanup(kill_l3proto, proto);
+}
+
+/* FIXME: Allow NULL functions and sub in pointers to generic for
+   them. --RR */
+int nf_conntrack_protocol_register(struct nf_conntrack_protocol *proto)
+{
+	int ret = 0;
+
+retry:
+	write_lock_bh(&nf_conntrack_lock);
+	if (nf_ct_protos[proto->l3proto]) {
+		if (nf_ct_protos[proto->l3proto][proto->proto]
+				!= &nf_conntrack_generic_protocol) {
+			ret = -EBUSY;
+			goto out_unlock;
+		}
+	} else {
+		/* l3proto may be loaded latter. */
+		struct nf_conntrack_protocol **proto_array;
+		int i;
+
+		write_unlock_bh(&nf_conntrack_lock);
+
+		proto_array = (struct nf_conntrack_protocol **)
+				kmalloc(MAX_NF_CT_PROTO *
+					 sizeof(struct nf_conntrack_protocol *),
+					GFP_KERNEL);
+		if (proto_array == NULL) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		for (i = 0; i < MAX_NF_CT_PROTO; i++)
+			proto_array[i] = &nf_conntrack_generic_protocol;
+
+		write_lock_bh(&nf_conntrack_lock);
+		if (nf_ct_protos[proto->l3proto]) {
+			/* bad timing, but no problem */
+			write_unlock_bh(&nf_conntrack_lock);
+			kfree(proto_array);
+		} else {
+			nf_ct_protos[proto->l3proto] = proto_array;
+			write_unlock_bh(&nf_conntrack_lock);
+		}
+
+		/*
+		 * Just once because array is never freed until unloading
+		 * nf_conntrack.ko
+		 */
+		goto retry;
+	}
+
+	nf_ct_protos[proto->l3proto][proto->proto] = proto;
+
+out_unlock:
+	write_unlock_bh(&nf_conntrack_lock);
+out:
+	return ret;
+}
+
+void nf_conntrack_protocol_unregister(struct nf_conntrack_protocol *proto)
+{
+	write_lock_bh(&nf_conntrack_lock);
+	nf_ct_protos[proto->l3proto][proto->proto]
+		= &nf_conntrack_generic_protocol;
+	write_unlock_bh(&nf_conntrack_lock);
+
+	/* Somebody could be still looking at the proto in bh. */
+	synchronize_net();
+
+	/* Remove all contrack entries for this protocol */
+	nf_ct_iterate_cleanup(kill_proto, proto);
+}