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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: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Arturo Borrero Gonzalez 2013-12-26 16:38:01 +01:00 committed by Pablo Neira Ayuso
parent d8bcc768c8
commit e035b77ac7
2 changed files with 129 additions and 27 deletions
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2
include/uapi/linux/netfilter/nf_tables.h
View File

@ -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)

140
net/netfilter/nft_meta.c
View File

@ -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 @@ static void nft_meta_eval(const struct nft_expr *expr,
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;
switch (key) {
case NFT_META_MARK:
case NFT_META_PRIORITY:
case NFT_META_NFTRACE:
return 0;
default:
return -EOPNOTSUPP;
}
}
if (tb[NFTA_META_DREG] == NULL ||
tb[NFTA_META_KEY] == NULL)
return -EINVAL;
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_DREG, htonl(priv->dreg)))
goto nla_put_failure;
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 @@ static int nft_meta_dump(struct sk_buff *skb, const struct nft_expr *expr)
}
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,