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Commit d734a288 authored by Laura Garcia Liebana's avatar Laura Garcia Liebana Committed by Pablo Neira Ayuso
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netfilter: nft_numgen: add map lookups for numgen statements 



This patch includes a new attribute in the numgen structure to allow
the lookup of an element based on the number generator as a key.

For this purpose, different ops have been included to extend the
current numgen inc functions.

Currently, only supported for numgen incremental operations, but
it will be supported for random in a follow-up patch.

Signed-off-by: default avatarLaura Garcia Liebana <nevola@gmail.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 8b2ebb6c

include/uapi/linux/netfilter/nf_tables.h

+4 −0
Original line number Diff line number Diff line
@@ -1450,6 +1450,8 @@ enum nft_trace_types { 
 * @NFTA_NG_MODULUS: maximum counter value (NLA_U32)

 * @NFTA_NG_TYPE: operation type (NLA_U32)

 * @NFTA_NG_OFFSET: offset to be added to the counter (NLA_U32)

 * @NFTA_NG_SET_NAME: name of the map to lookup (NLA_STRING)

 * @NFTA_NG_SET_ID: id of the map (NLA_U32)

 */

enum nft_ng_attributes {

	NFTA_NG_UNSPEC,
@@ -1457,6 +1459,8 @@ enum nft_ng_attributes { 
	NFTA_NG_MODULUS,

	NFTA_NG_TYPE,

	NFTA_NG_OFFSET,

	NFTA_NG_SET_NAME,

	NFTA_NG_SET_ID,

	__NFTA_NG_MAX

};

#define NFTA_NG_MAX	(__NFTA_NG_MAX - 1)

net/netfilter/nft_numgen.c

+80 −5
Original line number Diff line number Diff line
@@ -24,13 +24,11 @@ struct nft_ng_inc { 
	u32			modulus;

	atomic_t		counter;

	u32			offset;

	struct nft_set		*map;

};



static void nft_ng_inc_eval(const struct nft_expr *expr,

			    struct nft_regs *regs,

			    const struct nft_pktinfo *pkt)

static u32 nft_ng_inc_gen(struct nft_ng_inc *priv)

{

	struct nft_ng_inc *priv = nft_expr_priv(expr);

	u32 nval, oval;



	do {
@@ -38,7 +36,36 @@ static void nft_ng_inc_eval(const struct nft_expr *expr, 
		nval = (oval + 1 < priv->modulus) ? oval + 1 : 0;

	} while (atomic_cmpxchg(&priv->counter, oval, nval) != oval);



	regs->data[priv->dreg] = nval + priv->offset;

	return nval + priv->offset;

}



static void nft_ng_inc_eval(const struct nft_expr *expr,

			    struct nft_regs *regs,

			    const struct nft_pktinfo *pkt)

{

	struct nft_ng_inc *priv = nft_expr_priv(expr);



	regs->data[priv->dreg] = nft_ng_inc_gen(priv);

}



static void nft_ng_inc_map_eval(const struct nft_expr *expr,

				struct nft_regs *regs,

				const struct nft_pktinfo *pkt)

{

	struct nft_ng_inc *priv = nft_expr_priv(expr);

	const struct nft_set *map = priv->map;

	const struct nft_set_ext *ext;

	u32 result;

	bool found;



	result = nft_ng_inc_gen(priv);

	found = map->ops->lookup(nft_net(pkt), map, &result, &ext);



	if (!found)

		return;



	nft_data_copy(&regs->data[priv->dreg],

		      nft_set_ext_data(ext), map->dlen);

}



static const struct nla_policy nft_ng_policy[NFTA_NG_MAX + 1] = {
@@ -46,6 +73,9 @@ static const struct nla_policy nft_ng_policy[NFTA_NG_MAX + 1] = { 
	[NFTA_NG_MODULUS]	= { .type = NLA_U32 },

	[NFTA_NG_TYPE]		= { .type = NLA_U32 },

	[NFTA_NG_OFFSET]	= { .type = NLA_U32 },

	[NFTA_NG_SET_NAME]	= { .type = NLA_STRING,

				    .len = NFT_SET_MAXNAMELEN - 1 },

	[NFTA_NG_SET_ID]	= { .type = NLA_U32 },

};



static int nft_ng_inc_init(const struct nft_ctx *ctx,
@@ -71,6 +101,25 @@ static int nft_ng_inc_init(const struct nft_ctx *ctx, 
					   NFT_DATA_VALUE, sizeof(u32));

}



static int nft_ng_inc_map_init(const struct nft_ctx *ctx,

			       const struct nft_expr *expr,

			       const struct nlattr * const tb[])

{

	struct nft_ng_inc *priv = nft_expr_priv(expr);

	u8 genmask = nft_genmask_next(ctx->net);



	nft_ng_inc_init(ctx, expr, tb);



	priv->map = nft_set_lookup_global(ctx->net, ctx->table,

					  tb[NFTA_NG_SET_NAME],

					  tb[NFTA_NG_SET_ID], genmask);



	if (IS_ERR(priv->map))

		return PTR_ERR(priv->map);



	return 0;

}



static int nft_ng_dump(struct sk_buff *skb, enum nft_registers dreg,

		       u32 modulus, enum nft_ng_types type, u32 offset)

{
@@ -97,6 +146,22 @@ static int nft_ng_inc_dump(struct sk_buff *skb, const struct nft_expr *expr) 
			   priv->offset);

}



static int nft_ng_inc_map_dump(struct sk_buff *skb,

			       const struct nft_expr *expr)

{

	const struct nft_ng_inc *priv = nft_expr_priv(expr);



	if (nft_ng_dump(skb, priv->dreg, priv->modulus,

			NFT_NG_INCREMENTAL, priv->offset) ||

	    nla_put_string(skb, NFTA_NG_SET_NAME, priv->map->name))

		goto nla_put_failure;



	return 0;



nla_put_failure:

	return -1;

}



struct nft_ng_random {

	enum nft_registers      dreg:8;

	u32			modulus;
@@ -156,6 +221,14 @@ static const struct nft_expr_ops nft_ng_inc_ops = { 
	.dump		= nft_ng_inc_dump,

};



static const struct nft_expr_ops nft_ng_inc_map_ops = {

	.type		= &nft_ng_type,

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

	.eval		= nft_ng_inc_map_eval,

	.init		= nft_ng_inc_map_init,

	.dump		= nft_ng_inc_map_dump,

};



static const struct nft_expr_ops nft_ng_random_ops = {

	.type		= &nft_ng_type,

	.size		= NFT_EXPR_SIZE(sizeof(struct nft_ng_random)),
@@ -178,6 +251,8 @@ nft_ng_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 


	switch (type) {

	case NFT_NG_INCREMENTAL:

		if (tb[NFTA_NG_SET_NAME])

			return &nft_ng_inc_map_ops;

		return &nft_ng_inc_ops;

	case NFT_NG_RANDOM:

		return &nft_ng_random_ops;