Commit e035b77a authored by Arturo Borrero Gonzalez's avatar Arturo Borrero Gonzalez Committed by Pablo Neira Ayuso
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netfilter: nf_tables: nft_meta module get/set ops 



This patch adds kernel support for the meta expression in get/set
flavour. The set operation indicates that a given packet has to be
set with a property, currently one of mark, priority, nftrace.
The get op is what was currently working: evaluate the given
packet property.

In the nftrace case, the value is always 1. Such behaviour is copied
from net/netfilter/xt_TRACE.c

The NFTA_META_DREG and NFTA_META_SREG attributes are mutually
exclusives.

Signed-off-by: default avatarArturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent d8bcc768

include/uapi/linux/netfilter/nf_tables.h

+2 −0
Original line number Diff line number Diff line
@@ -555,11 +555,13 @@ enum nft_meta_keys { 
 *

 * @NFTA_META_DREG: destination register (NLA_U32)

 * @NFTA_META_KEY: meta data item to load (NLA_U32: nft_meta_keys)

 * @NFTA_META_SREG: source register (NLA_U32)

 */

enum nft_meta_attributes {

	NFTA_META_UNSPEC,

	NFTA_META_DREG,

	NFTA_META_KEY,

	NFTA_META_SREG,

	__NFTA_META_MAX

};

#define NFTA_META_MAX		(__NFTA_META_MAX - 1)

net/netfilter/nft_meta.c

+123 −23
Original line number Diff line number Diff line
@@ -21,10 +21,13 @@ 


struct nft_meta {

	enum nft_meta_keys	key:8;

	union {

		enum nft_registers	dreg:8;

		enum nft_registers	sreg:8;

	};

};



static void nft_meta_eval(const struct nft_expr *expr,

static void nft_meta_get_eval(const struct nft_expr *expr,

			      struct nft_data data[NFT_REG_MAX + 1],

			      const struct nft_pktinfo *pkt)

{
@@ -132,23 +135,50 @@ err: 
	data[NFT_REG_VERDICT].verdict = NFT_BREAK;

}



static void nft_meta_set_eval(const struct nft_expr *expr,

			      struct nft_data data[NFT_REG_MAX + 1],

			      const struct nft_pktinfo *pkt)

{

	const struct nft_meta *meta = nft_expr_priv(expr);

	struct sk_buff *skb = pkt->skb;

	u32 value = data[meta->sreg].data[0];



	switch (meta->key) {

	case NFT_META_MARK:

		skb->mark = value;

		break;

	case NFT_META_PRIORITY:

		skb->priority = value;

		break;

	case NFT_META_NFTRACE:

		skb->nf_trace = 1;

		break;

	default:

		WARN_ON(1);

	}

}



static const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {

	[NFTA_META_DREG]	= { .type = NLA_U32 },

	[NFTA_META_KEY]		= { .type = NLA_U32 },

	[NFTA_META_SREG]	= { .type = NLA_U32 },

};



static int nft_meta_init(const struct nft_ctx *ctx, const struct nft_expr *expr,

			 const struct nlattr * const tb[])

static int nft_meta_init_validate_set(uint32_t key)

{

	struct nft_meta *priv = nft_expr_priv(expr);

	int err;



	if (tb[NFTA_META_DREG] == NULL ||

	    tb[NFTA_META_KEY] == NULL)

		return -EINVAL;

	switch (key) {

	case NFT_META_MARK:

	case NFT_META_PRIORITY:

	case NFT_META_NFTRACE:

		return 0;

	default:

		return -EOPNOTSUPP;

	}

}



	priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));

	switch (priv->key) {

static int nft_meta_init_validate_get(uint32_t key)

{

	switch (key) {

	case NFT_META_LEN:

	case NFT_META_PROTOCOL:

	case NFT_META_PRIORITY:
@@ -167,26 +197,69 @@ static int nft_meta_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 
#ifdef CONFIG_NETWORK_SECMARK

	case NFT_META_SECMARK:

#endif

		break;

		return 0;

	default:

		return -EOPNOTSUPP;

	}



}



static int nft_meta_init(const struct nft_ctx *ctx, const struct nft_expr *expr,

			 const struct nlattr * const tb[])

{

	struct nft_meta *priv = nft_expr_priv(expr);

	int err;



	priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));



	if (tb[NFTA_META_DREG]) {

		err = nft_meta_init_validate_get(priv->key);

		if (err < 0)

			return err;



		priv->dreg = ntohl(nla_get_be32(tb[NFTA_META_DREG]));

		err = nft_validate_output_register(priv->dreg);

		if (err < 0)

			return err;

	return nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);



		return nft_validate_data_load(ctx, priv->dreg, NULL,

					      NFT_DATA_VALUE);

	}



	err = nft_meta_init_validate_set(priv->key);

	if (err < 0)

		return err;



	priv->sreg = ntohl(nla_get_be32(tb[NFTA_META_SREG]));



	return 0;

}



static int nft_meta_dump(struct sk_buff *skb, const struct nft_expr *expr)

static int nft_meta_get_dump(struct sk_buff *skb,

			     const struct nft_expr *expr)

{

	const struct nft_meta *priv = nft_expr_priv(expr);



	if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))

		goto nla_put_failure;

	if (nla_put_be32(skb, NFTA_META_DREG, htonl(priv->dreg)))

		goto nla_put_failure;

	return 0;



nla_put_failure:

	return -1;

}



static int nft_meta_set_dump(struct sk_buff *skb,

			     const struct nft_expr *expr)

{

	const struct nft_meta *priv = nft_expr_priv(expr);



	if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))

		goto nla_put_failure;

	if (nla_put_be32(skb, NFTA_META_SREG, htonl(priv->sreg)))

		goto nla_put_failure;



	return 0;



nla_put_failure:
@@ -194,17 +267,44 @@ nla_put_failure: 
}



static struct nft_expr_type nft_meta_type;

static const struct nft_expr_ops nft_meta_ops = {

static const struct nft_expr_ops nft_meta_get_ops = {

	.type		= &nft_meta_type,

	.size		= NFT_EXPR_SIZE(sizeof(struct nft_meta)),

	.eval		= nft_meta_eval,

	.eval		= nft_meta_get_eval,

	.init		= nft_meta_init,

	.dump		= nft_meta_dump,

	.dump		= nft_meta_get_dump,

};



static const struct nft_expr_ops nft_meta_set_ops = {

	.type		= &nft_meta_type,

	.size		= NFT_EXPR_SIZE(sizeof(struct nft_meta)),

	.eval		= nft_meta_set_eval,

	.init		= nft_meta_init,

	.dump		= nft_meta_set_dump,

};



static const struct nft_expr_ops *

nft_meta_select_ops(const struct nft_ctx *ctx,

		    const struct nlattr * const tb[])

{

	if (tb[NFTA_META_KEY] == NULL)

		return ERR_PTR(-EINVAL);



	if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])

		return ERR_PTR(-EINVAL);



	if (tb[NFTA_META_DREG])

		return &nft_meta_get_ops;



	if (tb[NFTA_META_SREG])

		return &nft_meta_set_ops;



	return ERR_PTR(-EINVAL);

}



static struct nft_expr_type nft_meta_type __read_mostly = {

	.name		= "meta",

	.ops		= &nft_meta_ops,

	.select_ops	= &nft_meta_select_ops,

	.policy		= nft_meta_policy,

	.maxattr	= NFTA_META_MAX,

	.owner		= THIS_MODULE,

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