On Wed, Sep 07, 2016 at 07:56:49PM +0200, Laura Garcia Liebana wrote:
> Add support for an initialization counter value. With this option the
> sysadmin is able to start the counter when used with the increment type.
>
> Example:
>
> meta mark set numgen inc mod 2 sum 100
>
> This will generate marks with the serie 100, 101, 100, 101, ...
>
> Only supported for increment number generation.
>
> Signed-off-by: Laura Garcia Liebana <nevola@xxxxxxxxx>
> ---
> Changes in v2:
> - Separate _SUM_ changes with _until_ attribute renaming.
>
> include/uapi/linux/netfilter/nf_tables.h | 2 ++
> net/netfilter/nft_numgen.c | 9 +++++++--
> 2 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
> index 24161e2..00a689d 100644
> --- a/include/uapi/linux/netfilter/nf_tables.h
> +++ b/include/uapi/linux/netfilter/nf_tables.h
> @@ -1128,12 +1128,14 @@ enum nft_trace_types {
> * @NFTA_NG_DREG: destination register (NLA_U32)
> * @NFTA_NG_MODULUS: maximum counter value (NLA_U32)
> * @NFTA_NG_TYPE: operation type (NLA_U32)
> + * @NFTA_NG_SUM: Offset to initiate the counter (NLA_U32)
> */
> enum nft_ng_attributes {
> NFTA_NG_UNSPEC,
> NFTA_NG_DREG,
> NFTA_NG_MODULUS,
> NFTA_NG_TYPE,
> + NFTA_NG_SUM,
> __NFTA_NG_MAX
> };
> #define NFTA_NG_MAX (__NFTA_NG_MAX - 1)
> diff --git a/net/netfilter/nft_numgen.c b/net/netfilter/nft_numgen.c
> index f51a3ed..a5ea3f7 100644
> --- a/net/netfilter/nft_numgen.c
> +++ b/net/netfilter/nft_numgen.c
> @@ -44,6 +44,7 @@ static const struct nla_policy nft_ng_policy[NFTA_NG_MAX + 1] = {
> [NFTA_NG_DREG] = { .type = NLA_U32 },
> [NFTA_NG_MODULUS] = { .type = NLA_U32 },
> [NFTA_NG_TYPE] = { .type = NLA_U32 },
> + [NFTA_NG_SUM] = { .type = NLA_U32 },
> };
>
> static int nft_ng_inc_init(const struct nft_ctx *ctx,
> @@ -51,13 +52,17 @@ static int nft_ng_inc_init(const struct nft_ctx *ctx,
> const struct nlattr * const tb[])
> {
> struct nft_ng_inc *priv = nft_expr_priv(expr);
> + u32 sum = 0;
> +
> + if (tb[NFTA_NG_SUM])
> + sum = ntohl(nla_get_be32(tb[NFTA_NG_SUM]));
>
> priv->modulus = ntohl(nla_get_be32(tb[NFTA_NG_MODULUS]));
> - if (priv->modulus == 0)
> + if (priv->modulus == 0 || sum >= priv->modulus)
> return -ERANGE;
>
> priv->dreg = nft_parse_register(tb[NFTA_NG_DREG]);
> - atomic_set(&priv->counter, 0);
> + atomic_set(&priv->counter, sum);
Are you sure this will work?
nval = (oval + 1 < priv->modulus) ? oval + 1 : 0;
This is just setting priv->counter to an initial value, then it will
become zero at some point.
I'm going to take Liping's patch that converts:
memcpy(®s->data[priv->dreg], &priv->counter, sizeof(u32));
to:
reg->data[priv->dreg] = nval;
so you can change this to:
reg->data[priv->dreg] = nval + priv->offset;
--
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