[deliverable/linux.git] / net / netfilter / nf_nat_proto_sctp.c

/*
 * 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)
{
	sctp_sctphdr_t *hdr;

	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;
	}

	hdr->checksum = sctp_compute_cksum(skb, hdroff);

	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 IS_ENABLED(CONFIG_NF_CT_NETLINK)
	.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>");
Commit	Line	Data
	1	/*
	2	* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*/
	8
	9	#include <linux/types.h>
	10	#include <linux/init.h>
	11	#include <linux/sctp.h>
	12	#include <linux/module.h>
	13	#include <net/sctp/checksum.h>
	14
	15	#include <net/netfilter/nf_nat_l4proto.h>
	16
	17	static u_int16_t nf_sctp_port_rover;
	18
	19	static void
	20	sctp_unique_tuple(const struct nf_nat_l3proto *l3proto,
	21	struct nf_conntrack_tuple *tuple,
	22	const struct nf_nat_range *range,
	23	enum nf_nat_manip_type maniptype,
	24	const struct nf_conn *ct)
	25	{
	26	nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
	27	&nf_sctp_port_rover);
	28	}
	29
	30	static bool
	31	sctp_manip_pkt(struct sk_buff *skb,
	32	const struct nf_nat_l3proto *l3proto,
	33	unsigned int iphdroff, unsigned int hdroff,
	34	const struct nf_conntrack_tuple *tuple,
	35	enum nf_nat_manip_type maniptype)
	36	{
	37	sctp_sctphdr_t *hdr;
	38
	39	if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
	40	return false;
	41
	42	hdr = (struct sctphdr *)(skb->data + hdroff);
	43
	44	if (maniptype == NF_NAT_MANIP_SRC) {
	45	/* Get rid of src port */
	46	hdr->source = tuple->src.u.sctp.port;
	47	} else {
	48	/* Get rid of dst port */
	49	hdr->dest = tuple->dst.u.sctp.port;
	50	}
	51
	52	hdr->checksum = sctp_compute_cksum(skb, hdroff);
	53
	54	return true;
	55	}
	56
	57	static const struct nf_nat_l4proto nf_nat_l4proto_sctp = {
	58	.l4proto = IPPROTO_SCTP,
	59	.manip_pkt = sctp_manip_pkt,
	60	.in_range = nf_nat_l4proto_in_range,
	61	.unique_tuple = sctp_unique_tuple,
	62	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
	63	.nlattr_to_range = nf_nat_l4proto_nlattr_to_range,
	64	#endif
	65	};
	66
	67	static int __init nf_nat_proto_sctp_init(void)
	68	{
	69	int err;
	70
	71	err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
	72	if (err < 0)
	73	goto err1;
	74	err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_sctp);
	75	if (err < 0)
	76	goto err2;
	77	return 0;
	78
	79	err2:
	80	nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
	81	err1:
	82	return err;
	83	}
	84
	85	static void __exit nf_nat_proto_sctp_exit(void)
	86	{
	87	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_sctp);
	88	nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
	89	}
	90
	91	module_init(nf_nat_proto_sctp_init);
	92	module_exit(nf_nat_proto_sctp_exit);
	93
	94	MODULE_LICENSE("GPL");
	95	MODULE_DESCRIPTION("SCTP NAT protocol helper");
	96	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");