[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]		= { .type = NLA_U32 },
	[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_addr.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 (priv->flags & ~NF_NAT_RANGE_MASK)
			return -EINVAL;
	}

	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)
{
	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_ipv4_eval(const struct nft_expr *expr,
			       struct nft_regs *regs,
			       const struct nft_pktinfo *pkt)
{
	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]);
	}
	regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb, nft_hook(pkt),
						    &range, nft_out(pkt));
}

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_ipv4_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_eval(const struct nft_expr *expr,
			       struct nft_regs *regs,
			       const struct nft_pktinfo *pkt)
{
	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]);
	}
	regs->verdict.code = nf_nat_masquerade_ipv6(pkt->skb, &range,
						    nft_out(pkt));
}

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_ipv6_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_eval(const struct nft_expr *expr,
			       struct nft_regs *regs,
			       const struct nft_pktinfo *pkt)
{
	switch (nft_pf(pkt)) {
	case NFPROTO_IPV4:
		return nft_masq_ipv4_eval(expr, regs, pkt);
	case NFPROTO_IPV6:
		return nft_masq_ipv6_eval(expr, regs, pkt);
	}

	WARN_ON_ONCE(1);
}

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_inet_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] = {
8a6bf5da PNA	23	[NFTA_MASQ_FLAGS] = { .type = NLA_U32 },
	24	[NFTA_MASQ_REG_PROTO_MIN] = { .type = NLA_U32 },
	25	[NFTA_MASQ_REG_PROTO_MAX] = { .type = NLA_U32 },
9ba1f726	26	};
9ba1f726	27
a9ce849e FW	28	static int nft_masq_validate(const struct nft_ctx *ctx,
	29	const struct nft_expr *expr,
	30	const struct nft_data **data)
75e8d06d PNA	31	{
	32	int err;
	33
	34	err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
	35	if (err < 0)
	36	return err;
	37
	38	return nft_chain_validate_hooks(ctx->chain,
	39	(1 << NF_INET_POST_ROUTING));
	40	}
75e8d06d	41
a9ce849e FW	42	static int nft_masq_init(const struct nft_ctx *ctx,
	43	const struct nft_expr *expr,
	44	const struct nlattr * const tb[])
9ba1f726	45	{
c593642c	46	u32 plen = sizeof_field(struct nf_nat_range, min_addr.all);
9ba1f726	47	struct nft_masq *priv = nft_expr_priv(expr);
7210e4e3 PNA	48	int err;
7210e4e3 PNA	49
8a6bf5da PNA	50	if (tb[NFTA_MASQ_FLAGS]) {
	51	priv->flags = ntohl(nla_get_be32(tb[NFTA_MASQ_FLAGS]));
	52	if (priv->flags & ~NF_NAT_RANGE_MASK)
	53	return -EINVAL;
	54	}
	55
	56	if (tb[NFTA_MASQ_REG_PROTO_MIN]) {
4f16d25c PNA	57	err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MIN],
4f16d25c PNA	58	&priv->sreg_proto_min, plen);
8a6bf5da PNA	59	if (err < 0)
	60	return err;
	61
	62	if (tb[NFTA_MASQ_REG_PROTO_MAX]) {
4f16d25c PNA	63	err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MAX],
	64	&priv->sreg_proto_max,
	65	plen);
8a6bf5da PNA	66	if (err < 0)
	67	return err;
	68	} else {
	69	priv->sreg_proto_max = priv->sreg_proto_min;
	70	}
	71	}
9ba1f726	72
36596dad	73	return nf_ct_netns_get(ctx->net, ctx->family);
9ba1f726	74	}
9ba1f726	75
a9ce849e	76	static int nft_masq_dump(struct sk_buff skb, const struct nft_expr expr)
9ba1f726 AB	77	{
	78	const struct nft_masq *priv = nft_expr_priv(expr);
	79
8a6bf5da PNA	80	if (priv->flags != 0 &&
8a6bf5da PNA	81	nla_put_be32(skb, NFTA_MASQ_FLAGS, htonl(priv->flags)))
9ba1f726 AB	82	goto nla_put_failure;
9ba1f726 AB	83
8a6bf5da PNA	84	if (priv->sreg_proto_min) {
	85	if (nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MIN,
	86	priv->sreg_proto_min) \|\|
	87	nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MAX,
	88	priv->sreg_proto_max))
	89	goto nla_put_failure;
	90	}
	91
9ba1f726 AB	92	return 0;
	93
	94	nla_put_failure:
	95	return -1;
	96	}
a9ce849e FW	97
	98	static void nft_masq_ipv4_eval(const struct nft_expr *expr,
	99	struct nft_regs *regs,
	100	const struct nft_pktinfo *pkt)
	101	{
	102	struct nft_masq *priv = nft_expr_priv(expr);
	103	struct nf_nat_range2 range;
	104
	105	memset(&range, 0, sizeof(range));
	106	range.flags = priv->flags;
	107	if (priv->sreg_proto_min) {
	108	range.min_proto.all = (__force __be16)nft_reg_load16(
	109	&regs->data[priv->sreg_proto_min]);
	110	range.max_proto.all = (__force __be16)nft_reg_load16(
	111	&regs->data[priv->sreg_proto_max]);
	112	}
	113	regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb, nft_hook(pkt),
	114	&range, nft_out(pkt));
	115	}
	116
	117	static void
	118	nft_masq_ipv4_destroy(const struct nft_ctx ctx, const struct nft_expr expr)
	119	{
	120	nf_ct_netns_put(ctx->net, NFPROTO_IPV4);
	121	}
	122
	123	static struct nft_expr_type nft_masq_ipv4_type;
	124	static const struct nft_expr_ops nft_masq_ipv4_ops = {
	125	.type = &nft_masq_ipv4_type,
	126	.size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
	127	.eval = nft_masq_ipv4_eval,
	128	.init = nft_masq_init,
	129	.destroy = nft_masq_ipv4_destroy,
	130	.dump = nft_masq_dump,
	131	.validate = nft_masq_validate,
b2d30654	132	.reduce = NFT_REDUCE_READONLY,
a9ce849e FW	133	};
	134
	135	static struct nft_expr_type nft_masq_ipv4_type __read_mostly = {
	136	.family = NFPROTO_IPV4,
	137	.name = "masq",
	138	.ops = &nft_masq_ipv4_ops,
	139	.policy = nft_masq_policy,
	140	.maxattr = NFTA_MASQ_MAX,
	141	.owner = THIS_MODULE,
	142	};
	143
	144	#ifdef CONFIG_NF_TABLES_IPV6
	145	static void nft_masq_ipv6_eval(const struct nft_expr *expr,
	146	struct nft_regs *regs,
	147	const struct nft_pktinfo *pkt)
	148	{
	149	struct nft_masq *priv = nft_expr_priv(expr);
	150	struct nf_nat_range2 range;
	151
	152	memset(&range, 0, sizeof(range));
	153	range.flags = priv->flags;
	154	if (priv->sreg_proto_min) {
	155	range.min_proto.all = (__force __be16)nft_reg_load16(
	156	&regs->data[priv->sreg_proto_min]);
	157	range.max_proto.all = (__force __be16)nft_reg_load16(
	158	&regs->data[priv->sreg_proto_max]);
	159	}
	160	regs->verdict.code = nf_nat_masquerade_ipv6(pkt->skb, &range,
	161	nft_out(pkt));
	162	}
	163
	164	static void
	165	nft_masq_ipv6_destroy(const struct nft_ctx ctx, const struct nft_expr expr)
	166	{
	167	nf_ct_netns_put(ctx->net, NFPROTO_IPV6);
	168	}
	169
	170	static struct nft_expr_type nft_masq_ipv6_type;
	171	static const struct nft_expr_ops nft_masq_ipv6_ops = {
	172	.type = &nft_masq_ipv6_type,
	173	.size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
	174	.eval = nft_masq_ipv6_eval,
	175	.init = nft_masq_init,
	176	.destroy = nft_masq_ipv6_destroy,
	177	.dump = nft_masq_dump,
	178	.validate = nft_masq_validate,
b2d30654	179	.reduce = NFT_REDUCE_READONLY,
a9ce849e FW	180	};
	181
	182	static struct nft_expr_type nft_masq_ipv6_type __read_mostly = {
	183	.family = NFPROTO_IPV6,
	184	.name = "masq",
	185	.ops = &nft_masq_ipv6_ops,
	186	.policy = nft_masq_policy,
	187	.maxattr = NFTA_MASQ_MAX,
	188	.owner = THIS_MODULE,
	189	};
	190
	191	static int __init nft_masq_module_init_ipv6(void)
	192	{
610a4314	193	return nft_register_expr(&nft_masq_ipv6_type);
a9ce849e FW	194	}
	195
	196	static void nft_masq_module_exit_ipv6(void)
	197	{
	198	nft_unregister_expr(&nft_masq_ipv6_type);
a9ce849e FW	199	}
	200	#else
	201	static inline int nft_masq_module_init_ipv6(void) { return 0; }
	202	static inline void nft_masq_module_exit_ipv6(void) {}
	203	#endif
	204
071657d2 FW	205	#ifdef CONFIG_NF_TABLES_INET
	206	static void nft_masq_inet_eval(const struct nft_expr *expr,
	207	struct nft_regs *regs,
	208	const struct nft_pktinfo *pkt)
	209	{
	210	switch (nft_pf(pkt)) {
	211	case NFPROTO_IPV4:
	212	return nft_masq_ipv4_eval(expr, regs, pkt);
	213	case NFPROTO_IPV6:
	214	return nft_masq_ipv6_eval(expr, regs, pkt);
	215	}
	216
	217	WARN_ON_ONCE(1);
	218	}
	219
	220	static void
	221	nft_masq_inet_destroy(const struct nft_ctx ctx, const struct nft_expr expr)
	222	{
	223	nf_ct_netns_put(ctx->net, NFPROTO_INET);
	224	}
	225
	226	static struct nft_expr_type nft_masq_inet_type;
	227	static const struct nft_expr_ops nft_masq_inet_ops = {
	228	.type = &nft_masq_inet_type,
	229	.size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
	230	.eval = nft_masq_inet_eval,
	231	.init = nft_masq_init,
	232	.destroy = nft_masq_inet_destroy,
	233	.dump = nft_masq_dump,
	234	.validate = nft_masq_validate,
b2d30654	235	.reduce = NFT_REDUCE_READONLY,
071657d2 FW	236	};
	237
	238	static struct nft_expr_type nft_masq_inet_type __read_mostly = {
	239	.family = NFPROTO_INET,
	240	.name = "masq",
	241	.ops = &nft_masq_inet_ops,
	242	.policy = nft_masq_policy,
	243	.maxattr = NFTA_MASQ_MAX,
	244	.owner = THIS_MODULE,
	245	};
	246
	247	static int __init nft_masq_module_init_inet(void)
	248	{
	249	return nft_register_expr(&nft_masq_inet_type);
	250	}
	251
	252	static void nft_masq_module_exit_inet(void)
	253	{
	254	nft_unregister_expr(&nft_masq_inet_type);
	255	}
	256	#else
	257	static inline int nft_masq_module_init_inet(void) { return 0; }
	258	static inline void nft_masq_module_exit_inet(void) {}
	259	#endif
	260
a9ce849e FW	261	static int __init nft_masq_module_init(void)
	262	{
	263	int ret;
	264
	265	ret = nft_masq_module_init_ipv6();
	266	if (ret < 0)
	267	return ret;
	268
071657d2 FW	269	ret = nft_masq_module_init_inet();
	270	if (ret < 0) {
	271	nft_masq_module_exit_ipv6();
	272	return ret;
	273	}
	274
a9ce849e FW	275	ret = nft_register_expr(&nft_masq_ipv4_type);
a9ce849e FW	276	if (ret < 0) {
071657d2	277	nft_masq_module_exit_inet();
a9ce849e FW	278	nft_masq_module_exit_ipv6();
	279	return ret;
	280	}
	281
610a4314	282	ret = nf_nat_masquerade_inet_register_notifiers();
a9ce849e FW	283	if (ret < 0) {
a9ce849e FW	284	nft_masq_module_exit_ipv6();
071657d2	285	nft_masq_module_exit_inet();
a9ce849e FW	286	nft_unregister_expr(&nft_masq_ipv4_type);
	287	return ret;
	288	}
	289
	290	return ret;
	291	}
	292
	293	static void __exit nft_masq_module_exit(void)
	294	{
	295	nft_masq_module_exit_ipv6();
071657d2	296	nft_masq_module_exit_inet();
a9ce849e	297	nft_unregister_expr(&nft_masq_ipv4_type);
610a4314	298	nf_nat_masquerade_inet_unregister_notifiers();
a9ce849e FW	299	}
	300
	301	module_init(nft_masq_module_init);
	302	module_exit(nft_masq_module_exit);
9ba1f726 AB	303
9ba1f726 AB	304	MODULE_LICENSE("GPL");
cd727514	305	MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo@debian.org>");
5142967a	306	MODULE_ALIAS_NFT_EXPR("masq");
4cacc395	307	MODULE_DESCRIPTION("Netfilter nftables masquerade expression support");