1 files changed, 103 insertions, 0 deletions
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>");