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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.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 <linux/ip.h>
#include <linux/ipv6.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_offload.h>
#include <net/netfilter/nf_dup_netdev.h>
#include <net/neighbour.h>
#include <net/ip.h>

struct nft_fwd_netdev {
	enum nft_registers	sreg_dev:8;
};

static void nft_fwd_netdev_eval(const struct nft_expr *expr,
				struct nft_regs *regs,
				const struct nft_pktinfo *pkt)
{
	struct nft_fwd_netdev *priv = nft_expr_priv(expr);
	int oif = regs->data[priv->sreg_dev];

	/* This is used by ifb only. */
	skb_set_redirected(pkt->skb, true);

	nf_fwd_netdev_egress(pkt, oif);
	regs->verdict.code = NF_STOLEN;
}

static const struct nla_policy nft_fwd_netdev_policy[NFTA_FWD_MAX + 1] = {
	[NFTA_FWD_SREG_DEV]	= { .type = NLA_U32 },
	[NFTA_FWD_SREG_ADDR]	= { .type = NLA_U32 },
	[NFTA_FWD_NFPROTO]	= { .type = NLA_U32 },
};

static int nft_fwd_netdev_init(const struct nft_ctx *ctx,
			       const struct nft_expr *expr,
			       const struct nlattr * const tb[])
{
	struct nft_fwd_netdev *priv = nft_expr_priv(expr);

	if (tb[NFTA_FWD_SREG_DEV] == NULL)
		return -EINVAL;

	priv->sreg_dev = nft_parse_register(tb[NFTA_FWD_SREG_DEV]);
	return nft_validate_register_load(priv->sreg_dev, sizeof(int));
}

static int nft_fwd_netdev_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
	struct nft_fwd_netdev *priv = nft_expr_priv(expr);

	if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev))
		goto nla_put_failure;

	return 0;

nla_put_failure:
	return -1;
}

static int nft_fwd_netdev_offload(struct nft_offload_ctx *ctx,
				  struct nft_flow_rule *flow,
				  const struct nft_expr *expr)
{
	const struct nft_fwd_netdev *priv = nft_expr_priv(expr);
	int oif = ctx->regs[priv->sreg_dev].data.data[0];

	return nft_fwd_dup_netdev_offload(ctx, flow, FLOW_ACTION_REDIRECT, oif);
}

struct nft_fwd_neigh {
	enum nft_registers	sreg_dev:8;
	enum nft_registers	sreg_addr:8;
	u8			nfproto;
};

static void nft_fwd_neigh_eval(const struct nft_expr *expr,
			      struct nft_regs *regs,
			      const struct nft_pktinfo *pkt)
{
	struct nft_fwd_neigh *priv = nft_expr_priv(expr);
	void *addr = &regs->data[priv->sreg_addr];
	int oif = regs->data[priv->sreg_dev];
	unsigned int verdict = NF_STOLEN;
	struct sk_buff *skb = pkt->skb;
	struct net_device *dev;
	int neigh_table;

	switch (priv->nfproto) {
	case NFPROTO_IPV4: {
		struct iphdr *iph;

		if (skb->protocol != htons(ETH_P_IP)) {
			verdict = NFT_BREAK;
			goto out;
		}
		if (skb_try_make_writable(skb, sizeof(*iph))) {
			verdict = NF_DROP;
			goto out;
		}
		iph = ip_hdr(skb);
		ip_decrease_ttl(iph);
		neigh_table = NEIGH_ARP_TABLE;
		break;
		}
	case NFPROTO_IPV6: {
		struct ipv6hdr *ip6h;

		if (skb->protocol != htons(ETH_P_IPV6)) {
			verdict = NFT_BREAK;
			goto out;
		}
		if (skb_try_make_writable(skb, sizeof(*ip6h))) {
			verdict = NF_DROP;
			goto out;
		}
		ip6h = ipv6_hdr(skb);
		ip6h->hop_limit--;
		neigh_table = NEIGH_ND_TABLE;
		break;
		}
	default:
		verdict = NFT_BREAK;
		goto out;
	}

	dev = dev_get_by_index_rcu(nft_net(pkt), oif);
	if (dev == NULL)
		return;

	skb->dev = dev;
	skb->tstamp = 0;
	neigh_xmit(neigh_table, dev, addr, skb);
out:
	regs->verdict.code = verdict;
}

static int nft_fwd_neigh_init(const struct nft_ctx *ctx,
			      const struct nft_expr *expr,
			      const struct nlattr * const tb[])
{
	struct nft_fwd_neigh *priv = nft_expr_priv(expr);
	unsigned int addr_len;
	int err;

	if (!tb[NFTA_FWD_SREG_DEV] ||
	    !tb[NFTA_FWD_SREG_ADDR] ||
	    !tb[NFTA_FWD_NFPROTO])
		return -EINVAL;

	priv->sreg_dev = nft_parse_register(tb[NFTA_FWD_SREG_DEV]);
	priv->sreg_addr = nft_parse_register(tb[NFTA_FWD_SREG_ADDR]);
	priv->nfproto = ntohl(nla_get_be32(tb[NFTA_FWD_NFPROTO]));

	switch (priv->nfproto) {
	case NFPROTO_IPV4:
		addr_len = sizeof(struct in_addr);
		break;
	case NFPROTO_IPV6:
		addr_len = sizeof(struct in6_addr);
		break;
	default:
		return -EOPNOTSUPP;
	}

	err = nft_validate_register_load(priv->sreg_dev, sizeof(int));
	if (err < 0)
		return err;

	return nft_validate_register_load(priv->sreg_addr, addr_len);
}

static int nft_fwd_neigh_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
	struct nft_fwd_neigh *priv = nft_expr_priv(expr);

	if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev) ||
	    nft_dump_register(skb, NFTA_FWD_SREG_ADDR, priv->sreg_addr) ||
	    nla_put_be32(skb, NFTA_FWD_NFPROTO, htonl(priv->nfproto)))
		goto nla_put_failure;

	return 0;

nla_put_failure:
	return -1;
}

static int nft_fwd_validate(const struct nft_ctx *ctx,
			    const struct nft_expr *expr,
			    const struct nft_data **data)
{
	return nft_chain_validate_hooks(ctx->chain, (1 << NF_NETDEV_INGRESS));
}

static struct nft_expr_type nft_fwd_netdev_type;
static const struct nft_expr_ops nft_fwd_neigh_netdev_ops = {
	.type		= &nft_fwd_netdev_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_fwd_neigh)),
	.eval		= nft_fwd_neigh_eval,
	.init		= nft_fwd_neigh_init,
	.dump		= nft_fwd_neigh_dump,
	.validate	= nft_fwd_validate,
};

static const struct nft_expr_ops nft_fwd_netdev_ops = {
	.type		= &nft_fwd_netdev_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_fwd_netdev)),
	.eval		= nft_fwd_netdev_eval,
	.init		= nft_fwd_netdev_init,
	.dump		= nft_fwd_netdev_dump,
	.validate	= nft_fwd_validate,
	.offload	= nft_fwd_netdev_offload,
};

static const struct nft_expr_ops *
nft_fwd_select_ops(const struct nft_ctx *ctx,
		   const struct nlattr * const tb[])
{
	if (tb[NFTA_FWD_SREG_ADDR])
		return &nft_fwd_neigh_netdev_ops;
	if (tb[NFTA_FWD_SREG_DEV])
		return &nft_fwd_netdev_ops;

        return ERR_PTR(-EOPNOTSUPP);
}

static struct nft_expr_type nft_fwd_netdev_type __read_mostly = {
	.family		= NFPROTO_NETDEV,
	.name		= "fwd",
	.select_ops	= nft_fwd_select_ops,
	.policy		= nft_fwd_netdev_policy,
	.maxattr	= NFTA_FWD_MAX,
	.owner		= THIS_MODULE,
};

static int __init nft_fwd_netdev_module_init(void)
{
	return nft_register_expr(&nft_fwd_netdev_type);
}

static void __exit nft_fwd_netdev_module_exit(void)
{
	nft_unregister_expr(&nft_fwd_netdev_type);
}

module_init(nft_fwd_netdev_module_init);
module_exit(nft_fwd_netdev_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_AF_EXPR(5, "fwd");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
39e6dea2 PNA	2	/*
39e6dea2 PNA	3	* Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
39e6dea2 PNA	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>
d32de98e PNA	12	#include <linux/ip.h>
d32de98e PNA	13	#include <linux/ipv6.h>
39e6dea2	14	#include <net/netfilter/nf_tables.h>
be2861dc	15	#include <net/netfilter/nf_tables_offload.h>
39e6dea2	16	#include <net/netfilter/nf_dup_netdev.h>
d32de98e PNA	17	#include <net/neighbour.h>
d32de98e PNA	18	#include <net/ip.h>
39e6dea2 PNA	19
	20	struct nft_fwd_netdev {
	21	enum nft_registers sreg_dev:8;
	22	};
	23
	24	static void nft_fwd_netdev_eval(const struct nft_expr *expr,
	25	struct nft_regs *regs,
	26	const struct nft_pktinfo *pkt)
	27	{
	28	struct nft_fwd_netdev *priv = nft_expr_priv(expr);
	29	int oif = regs->data[priv->sreg_dev];
	30
2c64605b PNA	31	/* This is used by ifb only. */
2c64605b PNA	32	skb_set_redirected(pkt->skb, true);
bcfabee1	33
3bf32761 FW	34	nf_fwd_netdev_egress(pkt, oif);
3bf32761 FW	35	regs->verdict.code = NF_STOLEN;
39e6dea2 PNA	36	}
	37
	38	static const struct nla_policy nft_fwd_netdev_policy[NFTA_FWD_MAX + 1] = {
	39	[NFTA_FWD_SREG_DEV] = { .type = NLA_U32 },
d32de98e PNA	40	[NFTA_FWD_SREG_ADDR] = { .type = NLA_U32 },
d32de98e PNA	41	[NFTA_FWD_NFPROTO] = { .type = NLA_U32 },
39e6dea2 PNA	42	};
	43
	44	static int nft_fwd_netdev_init(const struct nft_ctx *ctx,
	45	const struct nft_expr *expr,
	46	const struct nlattr * const tb[])
	47	{
	48	struct nft_fwd_netdev *priv = nft_expr_priv(expr);
	49
	50	if (tb[NFTA_FWD_SREG_DEV] == NULL)
	51	return -EINVAL;
	52
	53	priv->sreg_dev = nft_parse_register(tb[NFTA_FWD_SREG_DEV]);
	54	return nft_validate_register_load(priv->sreg_dev, sizeof(int));
	55	}
	56
39e6dea2 PNA	57	static int nft_fwd_netdev_dump(struct sk_buff skb, const struct nft_expr expr)
	58	{
	59	struct nft_fwd_netdev *priv = nft_expr_priv(expr);
	60
	61	if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev))
	62	goto nla_put_failure;
	63
	64	return 0;
	65
	66	nla_put_failure:
	67	return -1;
	68	}
	69
be2861dc PNA	70	static int nft_fwd_netdev_offload(struct nft_offload_ctx *ctx,
	71	struct nft_flow_rule *flow,
	72	const struct nft_expr *expr)
	73	{
	74	const struct nft_fwd_netdev *priv = nft_expr_priv(expr);
	75	int oif = ctx->regs[priv->sreg_dev].data.data[0];
	76
	77	return nft_fwd_dup_netdev_offload(ctx, flow, FLOW_ACTION_REDIRECT, oif);
	78	}
	79
d32de98e PNA	80	struct nft_fwd_neigh {
	81	enum nft_registers sreg_dev:8;
	82	enum nft_registers sreg_addr:8;
	83	u8 nfproto;
	84	};
	85
	86	static void nft_fwd_neigh_eval(const struct nft_expr *expr,
	87	struct nft_regs *regs,
	88	const struct nft_pktinfo *pkt)
	89	{
	90	struct nft_fwd_neigh *priv = nft_expr_priv(expr);
	91	void *addr = &regs->data[priv->sreg_addr];
	92	int oif = regs->data[priv->sreg_dev];
	93	unsigned int verdict = NF_STOLEN;
	94	struct sk_buff *skb = pkt->skb;
	95	struct net_device *dev;
	96	int neigh_table;
	97
	98	switch (priv->nfproto) {
	99	case NFPROTO_IPV4: {
	100	struct iphdr *iph;
	101
	102	if (skb->protocol != htons(ETH_P_IP)) {
	103	verdict = NFT_BREAK;
	104	goto out;
	105	}
	106	if (skb_try_make_writable(skb, sizeof(*iph))) {
	107	verdict = NF_DROP;
	108	goto out;
	109	}
	110	iph = ip_hdr(skb);
	111	ip_decrease_ttl(iph);
	112	neigh_table = NEIGH_ARP_TABLE;
	113	break;
	114	}
	115	case NFPROTO_IPV6: {
	116	struct ipv6hdr *ip6h;
	117
	118	if (skb->protocol != htons(ETH_P_IPV6)) {
	119	verdict = NFT_BREAK;
	120	goto out;
	121	}
	122	if (skb_try_make_writable(skb, sizeof(*ip6h))) {
	123	verdict = NF_DROP;
	124	goto out;
	125	}
	126	ip6h = ipv6_hdr(skb);
	127	ip6h->hop_limit--;
	128	neigh_table = NEIGH_ND_TABLE;
	129	break;
	130	}
	131	default:
	132	verdict = NFT_BREAK;
	133	goto out;
	134	}
	135
	136	dev = dev_get_by_index_rcu(nft_net(pkt), oif);
	137	if (dev == NULL)
	138	return;
	139
	140	skb->dev = dev;
c77761c8	141	skb->tstamp = 0;
d32de98e PNA	142	neigh_xmit(neigh_table, dev, addr, skb);
	143	out:
	144	regs->verdict.code = verdict;
	145	}
	146
	147	static int nft_fwd_neigh_init(const struct nft_ctx *ctx,
	148	const struct nft_expr *expr,
	149	const struct nlattr * const tb[])
	150	{
	151	struct nft_fwd_neigh *priv = nft_expr_priv(expr);
	152	unsigned int addr_len;
	153	int err;
	154
	155	if (!tb[NFTA_FWD_SREG_DEV] \|\|
	156	!tb[NFTA_FWD_SREG_ADDR] \|\|
	157	!tb[NFTA_FWD_NFPROTO])
	158	return -EINVAL;
	159
	160	priv->sreg_dev = nft_parse_register(tb[NFTA_FWD_SREG_DEV]);
	161	priv->sreg_addr = nft_parse_register(tb[NFTA_FWD_SREG_ADDR]);
	162	priv->nfproto = ntohl(nla_get_be32(tb[NFTA_FWD_NFPROTO]));
	163
	164	switch (priv->nfproto) {
	165	case NFPROTO_IPV4:
	166	addr_len = sizeof(struct in_addr);
	167	break;
	168	case NFPROTO_IPV6:
	169	addr_len = sizeof(struct in6_addr);
	170	break;
	171	default:
	172	return -EOPNOTSUPP;
	173	}
	174
	175	err = nft_validate_register_load(priv->sreg_dev, sizeof(int));
	176	if (err < 0)
	177	return err;
	178
	179	return nft_validate_register_load(priv->sreg_addr, addr_len);
	180	}
	181
d32de98e PNA	182	static int nft_fwd_neigh_dump(struct sk_buff skb, const struct nft_expr expr)
	183	{
	184	struct nft_fwd_neigh *priv = nft_expr_priv(expr);
	185
	186	if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev) \|\|
	187	nft_dump_register(skb, NFTA_FWD_SREG_ADDR, priv->sreg_addr) \|\|
	188	nla_put_be32(skb, NFTA_FWD_NFPROTO, htonl(priv->nfproto)))
	189	goto nla_put_failure;
	190
	191	return 0;
	192
	193	nla_put_failure:
	194	return -1;
	195	}
	196
76a109fa PNA	197	static int nft_fwd_validate(const struct nft_ctx *ctx,
	198	const struct nft_expr *expr,
	199	const struct nft_data **data)
	200	{
	201	return nft_chain_validate_hooks(ctx->chain, (1 << NF_NETDEV_INGRESS));
	202	}
	203
39e6dea2	204	static struct nft_expr_type nft_fwd_netdev_type;
d32de98e PNA	205	static const struct nft_expr_ops nft_fwd_neigh_netdev_ops = {
	206	.type = &nft_fwd_netdev_type,
	207	.size = NFT_EXPR_SIZE(sizeof(struct nft_fwd_neigh)),
	208	.eval = nft_fwd_neigh_eval,
	209	.init = nft_fwd_neigh_init,
	210	.dump = nft_fwd_neigh_dump,
76a109fa	211	.validate = nft_fwd_validate,
d32de98e PNA	212	};
d32de98e PNA	213
39e6dea2 PNA	214	static const struct nft_expr_ops nft_fwd_netdev_ops = {
	215	.type = &nft_fwd_netdev_type,
	216	.size = NFT_EXPR_SIZE(sizeof(struct nft_fwd_netdev)),
	217	.eval = nft_fwd_netdev_eval,
	218	.init = nft_fwd_netdev_init,
	219	.dump = nft_fwd_netdev_dump,
76a109fa	220	.validate = nft_fwd_validate,
be2861dc	221	.offload = nft_fwd_netdev_offload,
39e6dea2 PNA	222	};
39e6dea2 PNA	223
d32de98e PNA	224	static const struct nft_expr_ops *
	225	nft_fwd_select_ops(const struct nft_ctx *ctx,
	226	const struct nlattr * const tb[])
	227	{
	228	if (tb[NFTA_FWD_SREG_ADDR])
	229	return &nft_fwd_neigh_netdev_ops;
	230	if (tb[NFTA_FWD_SREG_DEV])
	231	return &nft_fwd_netdev_ops;
	232
	233	return ERR_PTR(-EOPNOTSUPP);
	234	}
	235
39e6dea2 PNA	236	static struct nft_expr_type nft_fwd_netdev_type __read_mostly = {
	237	.family = NFPROTO_NETDEV,
	238	.name = "fwd",
d32de98e	239	.select_ops = nft_fwd_select_ops,
39e6dea2 PNA	240	.policy = nft_fwd_netdev_policy,
	241	.maxattr = NFTA_FWD_MAX,
	242	.owner = THIS_MODULE,
	243	};
	244
	245	static int __init nft_fwd_netdev_module_init(void)
	246	{
	247	return nft_register_expr(&nft_fwd_netdev_type);
	248	}
	249
	250	static void __exit nft_fwd_netdev_module_exit(void)
	251	{
	252	nft_unregister_expr(&nft_fwd_netdev_type);
	253	}
	254
	255	module_init(nft_fwd_netdev_module_init);
	256	module_exit(nft_fwd_netdev_module_exit);
	257
	258	MODULE_LICENSE("GPL");
	259	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	260	MODULE_ALIAS_NFT_AF_EXPR(5, "fwd");