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_sctp.c b/net/netfilter/nf_nat_proto_sctp.c
new file mode 100644
index 0000000..e64faa5
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_sctp.c
@@ -0,0 +1,103 @@
+/*
+ * Copyright (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/sctp.h>
+#include <linux/module.h>
+#include <net/sctp/checksum.h>
+
+#include <net/netfilter/nf_nat_l4proto.h>
+
+static u_int16_t nf_sctp_port_rover;
+
+static void
+sctp_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,
+ &nf_sctp_port_rover);
+}
+
+static bool
+sctp_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 sk_buff *frag;
+ sctp_sctphdr_t *hdr;
+ __be32 crc32;
+
+ if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
+ return false;
+
+ hdr = (struct sctphdr *)(skb->data + hdroff);
+
+ if (maniptype == NF_NAT_MANIP_SRC) {
+ /* Get rid of src port */
+ hdr->source = tuple->src.u.sctp.port;
+ } else {
+ /* Get rid of dst port */
+ hdr->dest = tuple->dst.u.sctp.port;
+ }
+
+ crc32 = sctp_start_cksum((u8 *)hdr, skb_headlen(skb) - hdroff);
+ skb_walk_frags(skb, frag)
+ crc32 = sctp_update_cksum((u8 *)frag->data, skb_headlen(frag),
+ crc32);
+ crc32 = sctp_end_cksum(crc32);
+ hdr->checksum = crc32;
+
+ return true;
+}
+
+static const struct nf_nat_l4proto nf_nat_l4proto_sctp = {
+ .l4proto = IPPROTO_SCTP,
+ .manip_pkt = sctp_manip_pkt,
+ .in_range = nf_nat_l4proto_in_range,
+ .unique_tuple = sctp_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_sctp_init(void)
+{
+ int err;
+
+ err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
+ if (err < 0)
+ goto err1;
+ err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_sctp);
+ if (err < 0)
+ goto err2;
+ return 0;
+
+err2:
+ nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
+err1:
+ return err;
+}
+
+static void __exit nf_nat_proto_sctp_exit(void)
+{
+ nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_sctp);
+ nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
+}
+
+module_init(nf_nat_proto_sctp_init);
+module_exit(nf_nat_proto_sctp_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SCTP NAT protocol helper");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");