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Commit c4ede3d3 authored by Kristian Evensen's avatar Kristian Evensen Committed by Pablo Neira Ayuso
Browse files

netfilter: nft_ct: Add support to set the connmark 



This patch adds kernel support for setting properties of tracked
connections. Currently, only connmark is supported. One use-case
for this feature is to provide the same functionality as
-j CONNMARK --save-mark in iptables.

Some restructuring was needed to implement the set op. The new
structure follows that of nft_meta.

Signed-off-by: default avatarKristian Evensen <kristian.evensen@gmail.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 9638f33e

include/uapi/linux/netfilter/nf_tables.h

+2 −0
Original line number Diff line number Diff line
@@ -609,12 +609,14 @@ enum nft_ct_keys { 
 * @NFTA_CT_DREG: destination register (NLA_U32)

 * @NFTA_CT_KEY: conntrack data item to load (NLA_U32: nft_ct_keys)

 * @NFTA_CT_DIRECTION: direction in case of directional keys (NLA_U8)

 * @NFTA_CT_SREG: source register (NLA_U32)

 */

enum nft_ct_attributes {

	NFTA_CT_UNSPEC,

	NFTA_CT_DREG,

	NFTA_CT_KEY,

	NFTA_CT_DIRECTION,

	NFTA_CT_SREG,

	__NFTA_CT_MAX

};

#define NFTA_CT_MAX		(__NFTA_CT_MAX - 1)

net/netfilter/nft_ct.c

+134 −30
Original line number Diff line number Diff line
@@ -18,15 +18,19 @@ 
#include <net/netfilter/nf_conntrack.h>

#include <net/netfilter/nf_conntrack_tuple.h>

#include <net/netfilter/nf_conntrack_helper.h>

#include <net/netfilter/nf_conntrack_ecache.h>



struct nft_ct {

	enum nft_ct_keys	key:8;

	enum ip_conntrack_dir	dir:8;

	union{

		enum nft_registers	dreg:8;

		enum nft_registers	sreg:8;

	};

	uint8_t			family;

};



static void nft_ct_eval(const struct nft_expr *expr,

static void nft_ct_get_eval(const struct nft_expr *expr,

			    struct nft_data data[NFT_REG_MAX + 1],

			    const struct nft_pktinfo *pkt)

{
@@ -123,10 +127,37 @@ err: 
	data[NFT_REG_VERDICT].verdict = NFT_BREAK;

}



static void nft_ct_set_eval(const struct nft_expr *expr,

			    struct nft_data data[NFT_REG_MAX + 1],

			    const struct nft_pktinfo *pkt)

{

	const struct nft_ct *priv = nft_expr_priv(expr);

	struct sk_buff *skb = pkt->skb;

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

	enum ip_conntrack_info ctinfo;

	struct nf_conn *ct;



	ct = nf_ct_get(skb, &ctinfo);

	if (ct == NULL)

		return;



	switch (priv->key) {

#ifdef CONFIG_NF_CONNTRACK_MARK

	case NFT_CT_MARK:

		if (ct->mark != value) {

			ct->mark = value;

			nf_conntrack_event_cache(IPCT_MARK, ct);

		}

		break;

#endif

	}

}



static const struct nla_policy nft_ct_policy[NFTA_CT_MAX + 1] = {

	[NFTA_CT_DREG]		= { .type = NLA_U32 },

	[NFTA_CT_KEY]		= { .type = NLA_U32 },

	[NFTA_CT_DIRECTION]	= { .type = NLA_U8 },

	[NFTA_CT_SREG]		= { .type = NLA_U32 },

};



static int nft_ct_l3proto_try_module_get(uint8_t family)
@@ -162,18 +193,11 @@ static void nft_ct_l3proto_module_put(uint8_t family) 
		nf_ct_l3proto_module_put(family);

}



static int nft_ct_init(const struct nft_ctx *ctx,

		       const struct nft_expr *expr,

static int nft_ct_init_validate_get(const struct nft_expr *expr,

				    const struct nlattr * const tb[])

{

	struct nft_ct *priv = nft_expr_priv(expr);

	int err;



	if (tb[NFTA_CT_DREG] == NULL ||

	    tb[NFTA_CT_KEY] == NULL)

		return -EINVAL;



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

	if (tb[NFTA_CT_DIRECTION] != NULL) {

		priv->dir = nla_get_u8(tb[NFTA_CT_DIRECTION]);

		switch (priv->dir) {
@@ -212,26 +236,64 @@ static int nft_ct_init(const struct nft_ctx *ctx, 
		return -EOPNOTSUPP;

	}



	err = nft_ct_l3proto_try_module_get(ctx->afi->family);

	return 0;

}



static int nft_ct_init_validate_set(uint32_t key)

{

	switch (key) {

	case NFT_CT_MARK:

		break;

	default:

		return -EOPNOTSUPP;

	}



	return 0;

}



static int nft_ct_init(const struct nft_ctx *ctx,

		       const struct nft_expr *expr,

		       const struct nlattr * const tb[])

{

	struct nft_ct *priv = nft_expr_priv(expr);

	int err;



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



	if (tb[NFTA_CT_DREG]) {

		err = nft_ct_init_validate_get(expr, tb);

		if (err < 0)

			return err;

	priv->family = ctx->afi->family;



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

		err = nft_validate_output_register(priv->dreg);

		if (err < 0)

		goto err1;

			return err;



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

		err = nft_validate_data_load(ctx, priv->dreg, NULL,

					     NFT_DATA_VALUE);

		if (err < 0)

		goto err1;

	return 0;

			return err;

	} else {

		err = nft_ct_init_validate_set(priv->key);

		if (err < 0)

			return err;



err1:

	nft_ct_l3proto_module_put(ctx->afi->family);

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

		err = nft_validate_input_register(priv->sreg);

		if (err < 0)

			return err;

	}



	err = nft_ct_l3proto_try_module_get(ctx->afi->family);

	if (err < 0)

		return err;



	priv->family = ctx->afi->family;



	return 0;

}



static void nft_ct_destroy(const struct nft_expr *expr)

{

	struct nft_ct *priv = nft_expr_priv(expr);
@@ -239,7 +301,7 @@ static void nft_ct_destroy(const struct nft_expr *expr) 
	nft_ct_l3proto_module_put(priv->family);

}



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

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

{

	const struct nft_ct *priv = nft_expr_priv(expr);
@@ -255,19 +317,61 @@ nla_put_failure: 
	return -1;

}



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

{

	const struct nft_ct *priv = nft_expr_priv(expr);



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

		goto nla_put_failure;

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

		goto nla_put_failure;

	return 0;



nla_put_failure:

	return -1;

}



static struct nft_expr_type nft_ct_type;

static const struct nft_expr_ops nft_ct_ops = {

static const struct nft_expr_ops nft_ct_get_ops = {

	.type		= &nft_ct_type,

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

	.eval		= nft_ct_eval,

	.eval		= nft_ct_get_eval,

	.init		= nft_ct_init,

	.destroy	= nft_ct_destroy,

	.dump		= nft_ct_dump,

	.dump		= nft_ct_get_dump,

};



static const struct nft_expr_ops nft_ct_set_ops = {

	.type		= &nft_ct_type,

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

	.eval		= nft_ct_set_eval,

	.init		= nft_ct_init,

	.destroy	= nft_ct_destroy,

	.dump		= nft_ct_set_dump,

};



static const struct nft_expr_ops *

nft_ct_select_ops(const struct nft_ctx *ctx,

		    const struct nlattr * const tb[])

{

	if (tb[NFTA_CT_KEY] == NULL)

		return ERR_PTR(-EINVAL);



	if (tb[NFTA_CT_DREG] && tb[NFTA_CT_SREG])

		return ERR_PTR(-EINVAL);



	if (tb[NFTA_CT_DREG])

		return &nft_ct_get_ops;



	if (tb[NFTA_CT_SREG])

		return &nft_ct_set_ops;



	return ERR_PTR(-EINVAL);

}



static struct nft_expr_type nft_ct_type __read_mostly = {

	.name		= "ct",

	.ops		= &nft_ct_ops,

	.select_ops	= &nft_ct_select_ops,

	.policy		= nft_ct_policy,

	.maxattr	= NFTA_CT_MAX,

	.owner		= THIS_MODULE,