[mirror_ubuntu-artful-kernel.git] / net / netfilter / nf_nat_proto_common.c

/* (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/random.h>
#include <linux/netfilter.h>
#include <linux/export.h>

#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_core.h>
#include <net/netfilter/nf_nat_l3proto.h>
#include <net/netfilter/nf_nat_l4proto.h>

bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple,
			     enum nf_nat_manip_type maniptype,
			     const union nf_conntrack_man_proto *min,
			     const union nf_conntrack_man_proto *max)
{
	__be16 port;

	if (maniptype == NF_NAT_MANIP_SRC)
		port = tuple->src.u.all;
	else
		port = tuple->dst.u.all;

	return ntohs(port) >= ntohs(min->all) &&
	       ntohs(port) <= ntohs(max->all);
}
EXPORT_SYMBOL_GPL(nf_nat_l4proto_in_range);

void nf_nat_l4proto_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,
				 u16 *rover)
{
	unsigned int range_size, min, i;
	__be16 *portptr;
	u_int16_t off;

	if (maniptype == NF_NAT_MANIP_SRC)
		portptr = &tuple->src.u.all;
	else
		portptr = &tuple->dst.u.all;

	/* If no range specified... */
	if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
		/* If it's dst rewrite, can't change port */
		if (maniptype == NF_NAT_MANIP_DST)
			return;

		if (ntohs(*portptr) < 1024) {
			/* Loose convention: >> 512 is credential passing */
			if (ntohs(*portptr) < 512) {
				min = 1;
				range_size = 511 - min + 1;
			} else {
				min = 600;
				range_size = 1023 - min + 1;
			}
		} else {
			min = 1024;
			range_size = 65535 - 1024 + 1;
		}
	} else {
		min = ntohs(range->min_proto.all);
		range_size = ntohs(range->max_proto.all) - min + 1;
	}

	if (range->flags & NF_NAT_RANGE_PROTO_RANDOM) {
		off = l3proto->secure_port(tuple, maniptype == NF_NAT_MANIP_SRC
						  ? tuple->dst.u.all
						  : tuple->src.u.all);
	} else if (range->flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY) {
		off = prandom_u32();
	} else {
		off = *rover;
	}

	for (i = 0; ; ++off) {
		*portptr = htons(min + off % range_size);
		if (++i != range_size && nf_nat_used_tuple(tuple, ct))
			continue;
		if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL))
			*rover = off;
		return;
	}
}
EXPORT_SYMBOL_GPL(nf_nat_l4proto_unique_tuple);

#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
				   struct nf_nat_range *range)
{
	if (tb[CTA_PROTONAT_PORT_MIN]) {
		range->min_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MIN]);
		range->max_proto.all = range->min_proto.all;
		range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
	}
	if (tb[CTA_PROTONAT_PORT_MAX]) {
		range->max_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MAX]);
		range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(nf_nat_l4proto_nlattr_to_range);
#endif
Commit	Line	Data
937e0dfd PM	1	/* (C) 1999-2001 Paul `Rusty' Russell
	2	* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
	3	* (C) 2008 Patrick McHardy <kaber@trash.net>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*/
	9
	10	#include <linux/types.h>
	11	#include <linux/random.h>
937e0dfd	12	#include <linux/netfilter.h>
bc3b2d7f	13	#include <linux/export.h>
c7232c99	14
937e0dfd PM	15	#include <net/netfilter/nf_nat.h>
937e0dfd PM	16	#include <net/netfilter/nf_nat_core.h>
c7232c99 PM	17	#include <net/netfilter/nf_nat_l3proto.h>
c7232c99 PM	18	#include <net/netfilter/nf_nat_l4proto.h>
937e0dfd	19
c7232c99 PM	20	bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple,
	21	enum nf_nat_manip_type maniptype,
	22	const union nf_conntrack_man_proto *min,
	23	const union nf_conntrack_man_proto *max)
937e0dfd PM	24	{
	25	__be16 port;
	26
cbc9f2f4	27	if (maniptype == NF_NAT_MANIP_SRC)
937e0dfd PM	28	port = tuple->src.u.all;
	29	else
	30	port = tuple->dst.u.all;
	31
	32	return ntohs(port) >= ntohs(min->all) &&
	33	ntohs(port) <= ntohs(max->all);
	34	}
c7232c99	35	EXPORT_SYMBOL_GPL(nf_nat_l4proto_in_range);
937e0dfd	36
c7232c99 PM	37	void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
	38	struct nf_conntrack_tuple *tuple,
	39	const struct nf_nat_range *range,
	40	enum nf_nat_manip_type maniptype,
	41	const struct nf_conn *ct,
	42	u16 *rover)
937e0dfd PM	43	{
	44	unsigned int range_size, min, i;
	45	__be16 *portptr;
5abd363f	46	u_int16_t off;
937e0dfd	47
cbc9f2f4	48	if (maniptype == NF_NAT_MANIP_SRC)
937e0dfd PM	49	portptr = &tuple->src.u.all;
	50	else
	51	portptr = &tuple->dst.u.all;
	52
	53	/* If no range specified... */
cbc9f2f4	54	if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
937e0dfd	55	/* If it's dst rewrite, can't change port */
cbc9f2f4	56	if (maniptype == NF_NAT_MANIP_DST)
f43dc98b	57	return;
937e0dfd PM	58
	59	if (ntohs(*portptr) < 1024) {
	60	/* Loose convention: >> 512 is credential passing */
	61	if (ntohs(*portptr) < 512) {
	62	min = 1;
	63	range_size = 511 - min + 1;
	64	} else {
	65	min = 600;
	66	range_size = 1023 - min + 1;
	67	}
	68	} else {
	69	min = 1024;
	70	range_size = 65535 - 1024 + 1;
	71	}
	72	} else {
c7232c99 PM	73	min = ntohs(range->min_proto.all);
c7232c99 PM	74	range_size = ntohs(range->max_proto.all) - min + 1;
937e0dfd PM	75	}
937e0dfd PM	76
34ce3240	77	if (range->flags & NF_NAT_RANGE_PROTO_RANDOM) {
c7232c99 PM	78	off = l3proto->secure_port(tuple, maniptype == NF_NAT_MANIP_SRC
	79	? tuple->dst.u.all
	80	: tuple->src.u.all);
34ce3240 DB	81	} else if (range->flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY) {
	82	off = prandom_u32();
	83	} else {
9f593653	84	off = *rover;
34ce3240	85	}
937e0dfd	86
2452a99d	87	for (i = 0; ; ++off) {
5abd363f	88	*portptr = htons(min + off % range_size);
2452a99d	89	if (++i != range_size && nf_nat_used_tuple(tuple, ct))
5abd363f	90	continue;
34ce3240	91	if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL))
5abd363f	92	*rover = off;
f43dc98b	93	return;
937e0dfd	94	}
937e0dfd	95	}
c7232c99	96	EXPORT_SYMBOL_GPL(nf_nat_l4proto_unique_tuple);
535b57c7	97
24de3d37	98	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
c7232c99 PM	99	int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
c7232c99 PM	100	struct nf_nat_range *range)
535b57c7	101	{
535b57c7	102	if (tb[CTA_PROTONAT_PORT_MIN]) {
c7232c99 PM	103	range->min_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MIN]);
c7232c99 PM	104	range->max_proto.all = range->min_proto.all;
cbc9f2f4	105	range->flags \|= NF_NAT_RANGE_PROTO_SPECIFIED;
535b57c7	106	}
ca6a5074	107	if (tb[CTA_PROTONAT_PORT_MAX]) {
c7232c99	108	range->max_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MAX]);
cbc9f2f4	109	range->flags \|= NF_NAT_RANGE_PROTO_SPECIFIED;
535b57c7	110	}
ca6a5074	111	return 0;
535b57c7	112	}
c7232c99	113	EXPORT_SYMBOL_GPL(nf_nat_l4proto_nlattr_to_range);
535b57c7	114	#endif