[linux-block.git] / net / netfilter / nft_masq.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2014 Arturo Borrero Gonzalez <arturo@debian.org>
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_masquerade.h>

struct nft_masq {
	u32			flags;
	u8			sreg_proto_min;
	u8			sreg_proto_max;
};

static const struct nla_policy nft_masq_policy[NFTA_MASQ_MAX + 1] = {
	[NFTA_MASQ_FLAGS]		=
		NLA_POLICY_MASK(NLA_BE32, NF_NAT_RANGE_MASK),
	[NFTA_MASQ_REG_PROTO_MIN]	= { .type = NLA_U32 },
	[NFTA_MASQ_REG_PROTO_MAX]	= { .type = NLA_U32 },
};

static int nft_masq_validate(const struct nft_ctx *ctx,
			     const struct nft_expr *expr,
			     const struct nft_data **data)
{
	int err;

	err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
	if (err < 0)
		return err;

	return nft_chain_validate_hooks(ctx->chain,
				        (1 << NF_INET_POST_ROUTING));
}

static int nft_masq_init(const struct nft_ctx *ctx,
			 const struct nft_expr *expr,
			 const struct nlattr * const tb[])
{
	u32 plen = sizeof_field(struct nf_nat_range, min_proto.all);
	struct nft_masq *priv = nft_expr_priv(expr);
	int err;

	if (tb[NFTA_MASQ_FLAGS])
		priv->flags = ntohl(nla_get_be32(tb[NFTA_MASQ_FLAGS]));

	if (tb[NFTA_MASQ_REG_PROTO_MIN]) {
		err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MIN],
					      &priv->sreg_proto_min, plen);
		if (err < 0)
			return err;

		if (tb[NFTA_MASQ_REG_PROTO_MAX]) {
			err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MAX],
						      &priv->sreg_proto_max,
						      plen);
			if (err < 0)
				return err;
		} else {
			priv->sreg_proto_max = priv->sreg_proto_min;
		}
	}

	return nf_ct_netns_get(ctx->net, ctx->family);
}

static int nft_masq_dump(struct sk_buff *skb,
			 const struct nft_expr *expr, bool reset)
{
	const struct nft_masq *priv = nft_expr_priv(expr);

	if (priv->flags != 0 &&
	    nla_put_be32(skb, NFTA_MASQ_FLAGS, htonl(priv->flags)))
		goto nla_put_failure;

	if (priv->sreg_proto_min) {
		if (nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MIN,
				      priv->sreg_proto_min) ||
		    nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MAX,
				      priv->sreg_proto_max))
			goto nla_put_failure;
	}

	return 0;

nla_put_failure:
	return -1;
}

static void nft_masq_eval(const struct nft_expr *expr,
			  struct nft_regs *regs,
			  const struct nft_pktinfo *pkt)
{
	const struct nft_masq *priv = nft_expr_priv(expr);
	struct nf_nat_range2 range;

	memset(&range, 0, sizeof(range));
	range.flags = priv->flags;
	if (priv->sreg_proto_min) {
		range.min_proto.all = (__force __be16)
			nft_reg_load16(&regs->data[priv->sreg_proto_min]);
		range.max_proto.all = (__force __be16)
			nft_reg_load16(&regs->data[priv->sreg_proto_max]);
	}

	switch (nft_pf(pkt)) {
	case NFPROTO_IPV4:
		regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb,
							    nft_hook(pkt),
							    &range,
							    nft_out(pkt));
		break;
#ifdef CONFIG_NF_TABLES_IPV6
	case NFPROTO_IPV6:
		regs->verdict.code = nf_nat_masquerade_ipv6(pkt->skb, &range,
							    nft_out(pkt));
		break;
#endif
	default:
		WARN_ON_ONCE(1);
		break;
	}
}

static void
nft_masq_ipv4_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
	nf_ct_netns_put(ctx->net, NFPROTO_IPV4);
}

static struct nft_expr_type nft_masq_ipv4_type;
static const struct nft_expr_ops nft_masq_ipv4_ops = {
	.type		= &nft_masq_ipv4_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_masq)),
	.eval		= nft_masq_eval,
	.init		= nft_masq_init,
	.destroy	= nft_masq_ipv4_destroy,
	.dump		= nft_masq_dump,
	.validate	= nft_masq_validate,
	.reduce		= NFT_REDUCE_READONLY,
};

static struct nft_expr_type nft_masq_ipv4_type __read_mostly = {
	.family		= NFPROTO_IPV4,
	.name		= "masq",
	.ops		= &nft_masq_ipv4_ops,
	.policy		= nft_masq_policy,
	.maxattr	= NFTA_MASQ_MAX,
	.owner		= THIS_MODULE,
};

#ifdef CONFIG_NF_TABLES_IPV6
static void
nft_masq_ipv6_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
	nf_ct_netns_put(ctx->net, NFPROTO_IPV6);
}

static struct nft_expr_type nft_masq_ipv6_type;
static const struct nft_expr_ops nft_masq_ipv6_ops = {
	.type		= &nft_masq_ipv6_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_masq)),
	.eval		= nft_masq_eval,
	.init		= nft_masq_init,
	.destroy	= nft_masq_ipv6_destroy,
	.dump		= nft_masq_dump,
	.validate	= nft_masq_validate,
	.reduce		= NFT_REDUCE_READONLY,
};

static struct nft_expr_type nft_masq_ipv6_type __read_mostly = {
	.family		= NFPROTO_IPV6,
	.name		= "masq",
	.ops		= &nft_masq_ipv6_ops,
	.policy		= nft_masq_policy,
	.maxattr	= NFTA_MASQ_MAX,
	.owner		= THIS_MODULE,
};

static int __init nft_masq_module_init_ipv6(void)
{
	return nft_register_expr(&nft_masq_ipv6_type);
}

static void nft_masq_module_exit_ipv6(void)
{
	nft_unregister_expr(&nft_masq_ipv6_type);
}
#else
static inline int nft_masq_module_init_ipv6(void) { return 0; }
static inline void nft_masq_module_exit_ipv6(void) {}
#endif

#ifdef CONFIG_NF_TABLES_INET
static void
nft_masq_inet_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
	nf_ct_netns_put(ctx->net, NFPROTO_INET);
}

static struct nft_expr_type nft_masq_inet_type;
static const struct nft_expr_ops nft_masq_inet_ops = {
	.type		= &nft_masq_inet_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_masq)),
	.eval		= nft_masq_eval,
	.init		= nft_masq_init,
	.destroy	= nft_masq_inet_destroy,
	.dump		= nft_masq_dump,
	.validate	= nft_masq_validate,
	.reduce		= NFT_REDUCE_READONLY,
};

static struct nft_expr_type nft_masq_inet_type __read_mostly = {
	.family		= NFPROTO_INET,
	.name		= "masq",
	.ops		= &nft_masq_inet_ops,
	.policy		= nft_masq_policy,
	.maxattr	= NFTA_MASQ_MAX,
	.owner		= THIS_MODULE,
};

static int __init nft_masq_module_init_inet(void)
{
	return nft_register_expr(&nft_masq_inet_type);
}

static void nft_masq_module_exit_inet(void)
{
	nft_unregister_expr(&nft_masq_inet_type);
}
#else
static inline int nft_masq_module_init_inet(void) { return 0; }
static inline void nft_masq_module_exit_inet(void) {}
#endif

static int __init nft_masq_module_init(void)
{
	int ret;

	ret = nft_masq_module_init_ipv6();
	if (ret < 0)
		return ret;

	ret = nft_masq_module_init_inet();
	if (ret < 0) {
		nft_masq_module_exit_ipv6();
		return ret;
	}

	ret = nft_register_expr(&nft_masq_ipv4_type);
	if (ret < 0) {
		nft_masq_module_exit_inet();
		nft_masq_module_exit_ipv6();
		return ret;
	}

	ret = nf_nat_masquerade_inet_register_notifiers();
	if (ret < 0) {
		nft_masq_module_exit_ipv6();
		nft_masq_module_exit_inet();
		nft_unregister_expr(&nft_masq_ipv4_type);
		return ret;
	}

	return ret;
}

static void __exit nft_masq_module_exit(void)
{
	nft_masq_module_exit_ipv6();
	nft_masq_module_exit_inet();
	nft_unregister_expr(&nft_masq_ipv4_type);
	nf_nat_masquerade_inet_unregister_notifiers();
}

module_init(nft_masq_module_init);
module_exit(nft_masq_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo@debian.org>");
MODULE_ALIAS_NFT_EXPR("masq");
MODULE_DESCRIPTION("Netfilter nftables masquerade expression support");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
9ba1f726	2	/*
cd727514	3	* Copyright (c) 2014 Arturo Borrero Gonzalez <arturo@debian.org>
9ba1f726 AB	4	*/
	5
	6	#include <linux/kernel.h>
	7	#include <linux/init.h>
	8	#include <linux/module.h>
	9	#include <linux/netlink.h>
	10	#include <linux/netfilter.h>
	11	#include <linux/netfilter/nf_tables.h>
	12	#include <net/netfilter/nf_tables.h>
	13	#include <net/netfilter/nf_nat.h>
bf8981a2	14	#include <net/netfilter/nf_nat_masquerade.h>
9ba1f726	15
a9ce849e FW	16	struct nft_masq {
a9ce849e FW	17	u32 flags;
4f16d25c PNA	18	u8 sreg_proto_min;
4f16d25c PNA	19	u8 sreg_proto_max;
a9ce849e FW	20	};
	21
	22	static const struct nla_policy nft_masq_policy[NFTA_MASQ_MAX + 1] = {
100a11b6 FW	23	[NFTA_MASQ_FLAGS] =
100a11b6 FW	24	NLA_POLICY_MASK(NLA_BE32, NF_NAT_RANGE_MASK),
8a6bf5da PNA	25	[NFTA_MASQ_REG_PROTO_MIN] = { .type = NLA_U32 },
8a6bf5da PNA	26	[NFTA_MASQ_REG_PROTO_MAX] = { .type = NLA_U32 },
9ba1f726	27	};
9ba1f726	28
a9ce849e FW	29	static int nft_masq_validate(const struct nft_ctx *ctx,
	30	const struct nft_expr *expr,
	31	const struct nft_data **data)
75e8d06d PNA	32	{
	33	int err;
	34
	35	err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
	36	if (err < 0)
	37	return err;
	38
	39	return nft_chain_validate_hooks(ctx->chain,
	40	(1 << NF_INET_POST_ROUTING));
	41	}
75e8d06d	42
a9ce849e FW	43	static int nft_masq_init(const struct nft_ctx *ctx,
	44	const struct nft_expr *expr,
	45	const struct nlattr * const tb[])
9ba1f726	46	{
ec2c5917	47	u32 plen = sizeof_field(struct nf_nat_range, min_proto.all);
9ba1f726	48	struct nft_masq *priv = nft_expr_priv(expr);
7210e4e3 PNA	49	int err;
7210e4e3 PNA	50
100a11b6	51	if (tb[NFTA_MASQ_FLAGS])
8a6bf5da	52	priv->flags = ntohl(nla_get_be32(tb[NFTA_MASQ_FLAGS]));
8a6bf5da PNA	53
8a6bf5da PNA	54	if (tb[NFTA_MASQ_REG_PROTO_MIN]) {
4f16d25c PNA	55	err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MIN],
4f16d25c PNA	56	&priv->sreg_proto_min, plen);
8a6bf5da PNA	57	if (err < 0)
	58	return err;
	59
	60	if (tb[NFTA_MASQ_REG_PROTO_MAX]) {
4f16d25c PNA	61	err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MAX],
	62	&priv->sreg_proto_max,
	63	plen);
8a6bf5da PNA	64	if (err < 0)
	65	return err;
	66	} else {
	67	priv->sreg_proto_max = priv->sreg_proto_min;
	68	}
	69	}
9ba1f726	70
36596dad	71	return nf_ct_netns_get(ctx->net, ctx->family);
9ba1f726	72	}
9ba1f726	73
7d34aa3e PS	74	static int nft_masq_dump(struct sk_buff *skb,
7d34aa3e PS	75	const struct nft_expr *expr, bool reset)
9ba1f726 AB	76	{
	77	const struct nft_masq *priv = nft_expr_priv(expr);
	78
8a6bf5da PNA	79	if (priv->flags != 0 &&
8a6bf5da PNA	80	nla_put_be32(skb, NFTA_MASQ_FLAGS, htonl(priv->flags)))
9ba1f726 AB	81	goto nla_put_failure;
9ba1f726 AB	82
8a6bf5da PNA	83	if (priv->sreg_proto_min) {
	84	if (nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MIN,
	85	priv->sreg_proto_min) \|\|
	86	nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MAX,
	87	priv->sreg_proto_max))
	88	goto nla_put_failure;
	89	}
	90
9ba1f726 AB	91	return 0;
	92
	93	nla_put_failure:
	94	return -1;
	95	}
a9ce849e	96
f6ca5d5e JS	97	static void nft_masq_eval(const struct nft_expr *expr,
	98	struct nft_regs *regs,
	99	const struct nft_pktinfo *pkt)
a9ce849e	100	{
f6ca5d5e	101	const struct nft_masq *priv = nft_expr_priv(expr);
a9ce849e FW	102	struct nf_nat_range2 range;
	103
	104	memset(&range, 0, sizeof(range));
	105	range.flags = priv->flags;
	106	if (priv->sreg_proto_min) {
f6ca5d5e JS	107	range.min_proto.all = (__force __be16)
	108	nft_reg_load16(&regs->data[priv->sreg_proto_min]);
	109	range.max_proto.all = (__force __be16)
	110	nft_reg_load16(&regs->data[priv->sreg_proto_max]);
	111	}
	112
	113	switch (nft_pf(pkt)) {
	114	case NFPROTO_IPV4:
	115	regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb,
	116	nft_hook(pkt),
	117	&range,
	118	nft_out(pkt));
	119	break;
	120	#ifdef CONFIG_NF_TABLES_IPV6
	121	case NFPROTO_IPV6:
	122	regs->verdict.code = nf_nat_masquerade_ipv6(pkt->skb, &range,
	123	nft_out(pkt));
	124	break;
	125	#endif
	126	default:
	127	WARN_ON_ONCE(1);
	128	break;
a9ce849e	129	}
a9ce849e FW	130	}
	131
	132	static void
	133	nft_masq_ipv4_destroy(const struct nft_ctx ctx, const struct nft_expr expr)
	134	{
	135	nf_ct_netns_put(ctx->net, NFPROTO_IPV4);
	136	}
	137
	138	static struct nft_expr_type nft_masq_ipv4_type;
	139	static const struct nft_expr_ops nft_masq_ipv4_ops = {
	140	.type = &nft_masq_ipv4_type,
	141	.size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
f6ca5d5e	142	.eval = nft_masq_eval,
a9ce849e FW	143	.init = nft_masq_init,
	144	.destroy = nft_masq_ipv4_destroy,
	145	.dump = nft_masq_dump,
	146	.validate = nft_masq_validate,
b2d30654	147	.reduce = NFT_REDUCE_READONLY,
a9ce849e FW	148	};
	149
	150	static struct nft_expr_type nft_masq_ipv4_type __read_mostly = {
	151	.family = NFPROTO_IPV4,
	152	.name = "masq",
	153	.ops = &nft_masq_ipv4_ops,
	154	.policy = nft_masq_policy,
	155	.maxattr = NFTA_MASQ_MAX,
	156	.owner = THIS_MODULE,
	157	};
	158
	159	#ifdef CONFIG_NF_TABLES_IPV6
a9ce849e FW	160	static void
	161	nft_masq_ipv6_destroy(const struct nft_ctx ctx, const struct nft_expr expr)
	162	{
	163	nf_ct_netns_put(ctx->net, NFPROTO_IPV6);
	164	}
	165
	166	static struct nft_expr_type nft_masq_ipv6_type;
	167	static const struct nft_expr_ops nft_masq_ipv6_ops = {
	168	.type = &nft_masq_ipv6_type,
	169	.size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
f6ca5d5e	170	.eval = nft_masq_eval,
a9ce849e FW	171	.init = nft_masq_init,
	172	.destroy = nft_masq_ipv6_destroy,
	173	.dump = nft_masq_dump,
	174	.validate = nft_masq_validate,
b2d30654	175	.reduce = NFT_REDUCE_READONLY,
a9ce849e FW	176	};
	177
	178	static struct nft_expr_type nft_masq_ipv6_type __read_mostly = {
	179	.family = NFPROTO_IPV6,
	180	.name = "masq",
	181	.ops = &nft_masq_ipv6_ops,
	182	.policy = nft_masq_policy,
	183	.maxattr = NFTA_MASQ_MAX,
	184	.owner = THIS_MODULE,
	185	};
	186
	187	static int __init nft_masq_module_init_ipv6(void)
	188	{
610a4314	189	return nft_register_expr(&nft_masq_ipv6_type);
a9ce849e FW	190	}
	191
	192	static void nft_masq_module_exit_ipv6(void)
	193	{
	194	nft_unregister_expr(&nft_masq_ipv6_type);
a9ce849e FW	195	}
	196	#else
	197	static inline int nft_masq_module_init_ipv6(void) { return 0; }
	198	static inline void nft_masq_module_exit_ipv6(void) {}
	199	#endif
	200
071657d2	201	#ifdef CONFIG_NF_TABLES_INET
071657d2 FW	202	static void
	203	nft_masq_inet_destroy(const struct nft_ctx ctx, const struct nft_expr expr)
	204	{
	205	nf_ct_netns_put(ctx->net, NFPROTO_INET);
	206	}
	207
	208	static struct nft_expr_type nft_masq_inet_type;
	209	static const struct nft_expr_ops nft_masq_inet_ops = {
	210	.type = &nft_masq_inet_type,
	211	.size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
f6ca5d5e	212	.eval = nft_masq_eval,
071657d2 FW	213	.init = nft_masq_init,
	214	.destroy = nft_masq_inet_destroy,
	215	.dump = nft_masq_dump,
	216	.validate = nft_masq_validate,
b2d30654	217	.reduce = NFT_REDUCE_READONLY,
071657d2 FW	218	};
	219
	220	static struct nft_expr_type nft_masq_inet_type __read_mostly = {
	221	.family = NFPROTO_INET,
	222	.name = "masq",
	223	.ops = &nft_masq_inet_ops,
	224	.policy = nft_masq_policy,
	225	.maxattr = NFTA_MASQ_MAX,
	226	.owner = THIS_MODULE,
	227	};
	228
	229	static int __init nft_masq_module_init_inet(void)
	230	{
	231	return nft_register_expr(&nft_masq_inet_type);
	232	}
	233
	234	static void nft_masq_module_exit_inet(void)
	235	{
	236	nft_unregister_expr(&nft_masq_inet_type);
	237	}
	238	#else
	239	static inline int nft_masq_module_init_inet(void) { return 0; }
	240	static inline void nft_masq_module_exit_inet(void) {}
	241	#endif
	242
a9ce849e FW	243	static int __init nft_masq_module_init(void)
	244	{
	245	int ret;
	246
	247	ret = nft_masq_module_init_ipv6();
	248	if (ret < 0)
	249	return ret;
	250
071657d2 FW	251	ret = nft_masq_module_init_inet();
	252	if (ret < 0) {
	253	nft_masq_module_exit_ipv6();
	254	return ret;
	255	}
	256
a9ce849e FW	257	ret = nft_register_expr(&nft_masq_ipv4_type);
a9ce849e FW	258	if (ret < 0) {
071657d2	259	nft_masq_module_exit_inet();
a9ce849e FW	260	nft_masq_module_exit_ipv6();
	261	return ret;
	262	}
	263
610a4314	264	ret = nf_nat_masquerade_inet_register_notifiers();
a9ce849e FW	265	if (ret < 0) {
a9ce849e FW	266	nft_masq_module_exit_ipv6();
071657d2	267	nft_masq_module_exit_inet();
a9ce849e FW	268	nft_unregister_expr(&nft_masq_ipv4_type);
	269	return ret;
	270	}
	271
	272	return ret;
	273	}
	274
	275	static void __exit nft_masq_module_exit(void)
	276	{
	277	nft_masq_module_exit_ipv6();
071657d2	278	nft_masq_module_exit_inet();
a9ce849e	279	nft_unregister_expr(&nft_masq_ipv4_type);
610a4314	280	nf_nat_masquerade_inet_unregister_notifiers();
a9ce849e FW	281	}
	282
	283	module_init(nft_masq_module_init);
	284	module_exit(nft_masq_module_exit);
9ba1f726 AB	285
9ba1f726 AB	286	MODULE_LICENSE("GPL");
cd727514	287	MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo@debian.org>");
5142967a	288	MODULE_ALIAS_NFT_EXPR("masq");
4cacc395	289	MODULE_DESCRIPTION("Netfilter nftables masquerade expression support");