netfilter: add protocol independent NAT core
Convert the IPv4 NAT implementation to a protocol independent core and
address family specific modules.
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/nf_nat_proto_dccp.c b/net/netfilter/nf_nat_proto_dccp.c
new file mode 100644
index 0000000..c8be2cd
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_dccp.c
@@ -0,0 +1,116 @@
+/*
+ * DCCP NAT protocol helper
+ *
+ * Copyright (c) 2005, 2006, 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/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/dccp.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+
+static u_int16_t dccp_port_rover;
+
+static void
+dccp_unique_tuple(const struct nf_nat_l3proto *l3proto,
+ struct nf_conntrack_tuple *tuple,
+ const struct nf_nat_range *range,
+ enum nf_nat_manip_type maniptype,
+ const struct nf_conn *ct)
+{
+ nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+ &dccp_port_rover);
+}
+
+static bool
+dccp_manip_pkt(struct sk_buff *skb,
+ const struct nf_nat_l3proto *l3proto,
+ unsigned int iphdroff, unsigned int hdroff,
+ const struct nf_conntrack_tuple *tuple,
+ enum nf_nat_manip_type maniptype)
+{
+ struct dccp_hdr *hdr;
+ __be16 *portptr, oldport, newport;
+ int hdrsize = 8; /* DCCP connection tracking guarantees this much */
+
+ if (skb->len >= hdroff + sizeof(struct dccp_hdr))
+ hdrsize = sizeof(struct dccp_hdr);
+
+ if (!skb_make_writable(skb, hdroff + hdrsize))
+ return false;
+
+ hdr = (struct dccp_hdr *)(skb->data + hdroff);
+
+ if (maniptype == NF_NAT_MANIP_SRC) {
+ newport = tuple->src.u.dccp.port;
+ portptr = &hdr->dccph_sport;
+ } else {
+ newport = tuple->dst.u.dccp.port;
+ portptr = &hdr->dccph_dport;
+ }
+
+ oldport = *portptr;
+ *portptr = newport;
+
+ if (hdrsize < sizeof(*hdr))
+ return true;
+
+ l3proto->csum_update(skb, iphdroff, &hdr->dccph_checksum,
+ tuple, maniptype);
+ inet_proto_csum_replace2(&hdr->dccph_checksum, skb, oldport, newport,
+ 0);
+ return true;
+}
+
+static const struct nf_nat_l4proto nf_nat_l4proto_dccp = {
+ .l4proto = IPPROTO_DCCP,
+ .manip_pkt = dccp_manip_pkt,
+ .in_range = nf_nat_l4proto_in_range,
+ .unique_tuple = dccp_unique_tuple,
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+ .nlattr_to_range = nf_nat_l4proto_nlattr_to_range,
+#endif
+};
+
+static int __init nf_nat_proto_dccp_init(void)
+{
+ int err;
+
+ err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_dccp);
+ if (err < 0)
+ goto err1;
+ err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_dccp);
+ if (err < 0)
+ goto err2;
+ return 0;
+
+err2:
+ nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_dccp);
+err1:
+ return err;
+}
+
+static void __exit nf_nat_proto_dccp_fini(void)
+{
+ nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_dccp);
+ nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_dccp);
+
+}
+
+module_init(nf_nat_proto_dccp_init);
+module_exit(nf_nat_proto_dccp_fini);
+
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_DESCRIPTION("DCCP NAT protocol helper");
+MODULE_LICENSE("GPL");