[NETFILTER]: nf_nat: add UDP-Lite support

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 99 insertions, 0 deletions

diff --git a/net/ipv4/netfilter/nf_nat_proto_udplite.c b/net/ipv4/netfilter/nf_nat_proto_udplite.c
new file mode 100644
index 000000000000..b29346d0e7ab
--- /dev/null
+++ b/net/ipv4/netfilter/nf_nat_proto_udplite.c
@@ -0,0 +1,99 @@
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2008 Patrick McHardy <kaber@trash.net>
+ *
+ * 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/init.h>
+#include <linux/ip.h>
+#include <linux/udp.h>
+
+#include <linux/netfilter.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_protocol.h>
+
+static u_int16_t udplite_port_rover;
+
+static int
+udplite_unique_tuple(struct nf_conntrack_tuple *tuple,
+		     const struct nf_nat_range *range,
+		     enum nf_nat_manip_type maniptype,
+		     const struct nf_conn *ct)
+{
+	return nf_nat_proto_unique_tuple(tuple, range, maniptype, ct,
+					 &udplite_port_rover);
+}
+
+static int
+udplite_manip_pkt(struct sk_buff *skb,
+		  unsigned int iphdroff,
+		  const struct nf_conntrack_tuple *tuple,
+		  enum nf_nat_manip_type maniptype)
+{
+	const struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff);
+	struct udphdr *hdr;
+	unsigned int hdroff = iphdroff + iph->ihl*4;
+	__be32 oldip, newip;
+	__be16 *portptr, newport;
+
+	if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
+		return 0;
+
+	iph = (struct iphdr *)(skb->data + iphdroff);
+	hdr = (struct udphdr *)(skb->data + hdroff);
+
+	if (maniptype == IP_NAT_MANIP_SRC) {
+		/* Get rid of src ip and src pt */
+		oldip = iph->saddr;
+		newip = tuple->src.u3.ip;
+		newport = tuple->src.u.udp.port;
+		portptr = &hdr->source;
+	} else {
+		/* Get rid of dst ip and dst pt */
+		oldip = iph->daddr;
+		newip = tuple->dst.u3.ip;
+		newport = tuple->dst.u.udp.port;
+		portptr = &hdr->dest;
+	}
+
+	inet_proto_csum_replace4(&hdr->check, skb, oldip, newip, 1);
+	inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport, 0);
+	if (!hdr->check)
+		hdr->check = CSUM_MANGLED_0;
+
+	*portptr = newport;
+	return 1;
+}
+
+static const struct nf_nat_protocol nf_nat_protocol_udplite = {
+	.protonum		= IPPROTO_UDPLITE,
+	.me			= THIS_MODULE,
+	.manip_pkt		= udplite_manip_pkt,
+	.in_range		= nf_nat_proto_in_range,
+	.unique_tuple		= udplite_unique_tuple,
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.range_to_nlattr	= nf_nat_proto_range_to_nlattr,
+	.nlattr_to_range	= nf_nat_proto_nlattr_to_range,
+#endif
+};
+
+static int __init nf_nat_proto_udplite_init(void)
+{
+	return nf_nat_protocol_register(&nf_nat_protocol_udplite);
+}
+
+static void __exit nf_nat_proto_udplite_fini(void)
+{
+	nf_nat_protocol_unregister(&nf_nat_protocol_udplite);
+}
+
+module_init(nf_nat_proto_udplite_init);
+module_exit(nf_nat_proto_udplite_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("UDP-Lite NAT protocol helper");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");