[NETFILTER]: nf_nat: add UDP-Lite support

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

4 files changed, 109 insertions, 2 deletions

diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 9a077cb24798..c5bd2840663b 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -245,6 +245,11 @@ config NF_NAT_PROTO_GRE
         tristate
         depends on NF_NAT && NF_CT_PROTO_GRE
 
+config NF_NAT_PROTO_UDPLITE
+        tristate
+        depends on NF_NAT && NF_CT_PROTO_UDPLITE
+        default NF_NAT && NF_CT_PROTO_UDPLITE
+
 config NF_NAT_FTP
         tristate
         depends on IP_NF_IPTABLES && NF_CONNTRACK && NF_NAT
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index e73d0eb9994a..332f46fbc756 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_NF_NAT_TFTP) += nf_nat_tftp.o
 
 # NAT protocols (nf_nat)
 obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o
+obj-$(CONFIG_NF_NAT_PROTO_UDPLITE) += nf_nat_proto_udplite.o
 
 # generic IP tables 
 obj-$(CONFIG_IP_NF_IPTABLES) += ip_tables.o
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>");
diff --git a/net/ipv4/netfilter/nf_nat_standalone.c b/net/ipv4/netfilter/nf_nat_standalone.c
index 9fba42d9cdea..dc316b9f9b1d 100644
--- a/net/ipv4/netfilter/nf_nat_standalone.c
+++ b/net/ipv4/netfilter/nf_nat_standalone.c
@@ -50,7 +50,8 @@ static void nat_decode_session(struct sk_buff *skb, struct flowi *fl)
         if (ct->status & statusbit) {
                 fl->fl4_dst = t->dst.u3.ip;
                 if (t->dst.protonum == IPPROTO_TCP ||
-                    t->dst.protonum == IPPROTO_UDP)
+                    t->dst.protonum == IPPROTO_UDP ||
+                    t->dst.protonum == IPPROTO_UDPLITE)
                         fl->fl_ip_dport = t->dst.u.tcp.port;
         }
 
@@ -59,7 +60,8 @@ static void nat_decode_session(struct sk_buff *skb, struct flowi *fl)
         if (ct->status & statusbit) {
                 fl->fl4_src = t->src.u3.ip;
                 if (t->dst.protonum == IPPROTO_TCP ||
-                    t->dst.protonum == IPPROTO_UDP)
+                    t->dst.protonum == IPPROTO_UDP ||
+                    t->dst.protonum == IPPROTO_UDPLITE)
                         fl->fl_ip_sport = t->src.u.tcp.port;
         }
 }