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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: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Laura Garcia Liebana 2018-04-22 11:03:23 +02:00 committed by Pablo Neira Ayuso
parent 8b2ebb6cf0
commit d734a28889
2 changed files with 84 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/uapi/linux/netfilter/nf_tables.h
View File

@ -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)

85
net/netfilter/nft_numgen.c
View File

@ -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;