netfilter: nf_tables: add hash expression
Subsystems (2)
PATCH v2 1/1 netfilter: nf_tables: add hash expression
This patch adds a new hash expression, this provides jhash support but this can be extended to support for other hash functions.
The modulus and seed already comes embedded into this new expression.
Use case example:
meta mark set hash ip saddr mod 10
---
Changes in V2:
- Define len as u8 instead of u32
- Improved module description
- Remove unnecessary includes
include/uapi/linux/netfilter/nf_tables.h | 20 +++++ net/netfilter/Kconfig | 6 ++ net/netfilter/Makefile | 1 + net/netfilter/nft_hash.c | 133 +++++++++++++++++++++++++++++++ 4 files changed, 160 insertions(+) create mode 100644 net/netfilter/nft_hash.c
include/uapi/linux/netfilter/nf_tables.h +20 -0
@@ -724,6 +724,26 @@ enum nft_meta_keys { };/** +* enum nft_hash_attributes - nf_tables hash expression netlink attributes +* +* @NFTA_HASH_SREG: source register (NLA_U32) +* @NFTA_HASH_DREG: destination register (NLA_U32) +* @NFTA_HASH_LEN: source data length (NLA_U32) +* @NFTA_HASH_MODULUS: modulus value (NLA_U32) +* @NFTA_HASH_SEED: seed value (NLA_U32) +*/ +enum nft_hash_attributes { +NFTA_HASH_UNSPEC , +NFTA_HASH_SREG , +NFTA_HASH_DREG , +NFTA_HASH_LEN , +NFTA_HASH_MODULUS , +NFTA_HASH_SEED , + __NFTA_HASH_MAX, +}; +#define NFTA_HASH_MAX (__NFTA_HASH_MAX - 1) + +/** * enum nft_meta_attributes - nf_tables meta expression netlink attributes * * @NFTA_META_DREG: destination register (NLA_U32)
net/netfilter/Kconfig +6 -0
@@ -569,6 +569,12 @@ config NFT_COMPAT x_tables match/target extensions over the nf_tables framework. +config NFT_HASH + tristate "Netfilter nf_tables hash module" + help + This option adds the "hash" expression that you can use to perform + a hash operation on registers. + if NF_TABLES_NETDEV config NF_DUP_NETDEV
net/netfilter/Makefile +1 -0
@@ -93,6 +93,7 @@ obj-$(CONFIG_NFT_COUNTER) += nft_counter.o obj-$(CONFIG_NFT_LOG) += nft_log.o obj-$(CONFIG_NFT_MASQ) += nft_masq.o obj-$(CONFIG_NFT_REDIR) += nft_redir.o +obj-$(CONFIG_NFT_HASH) += nft_hash.o # nf_tables netdev obj-$(CONFIG_NFT_DUP_NETDEV) += nft_dup_netdev.o
net/netfilter/nft_hash.c new file +133 -0
133 lines not on this page · raw message
Signature · 1 line
2.8.1
Hi Laura,
2016-08-10 2:22 GMT+08:00 Laura Garcia Liebana <[email protected]>:
Quoted 9 lines
This patch adds a new hash expression, this provides jhash support but this can be extended to support for other hash functions.
The modulus and seed already comes embedded into this new expression.
Use case example:
meta mark set hash ip saddr mod 10net/netfilter/nft_hash.c new file +1
-0+static int nft_hash_init(const struct nft_ctx *ctx,
net/netfilter/nft_hash.c line 59
Quoted 10 lines
net/netfilter/nft_hash.c new file +10
-0+const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_hash *priv = nft_expr_priv(expr); +u32 len; + +if (!tb[NFTA_HASH_SREG ] || + !tb[NFTA_HASH_DREG ] || + !tb[NFTA_HASH_LEN ]) +return -EINVAL ;
I think tb[NFTA_HASH_MODULUS] and tb[NFTA_HASH_SEED] should also be checked is NULL or not? :)
net/netfilter/nft_hash.c line 62
Quoted 3 lines
net/netfilter/nft_hash.c new file +3
-0+ + priv->sreg =nft_parse_register (tb[NFTA_HASH_SREG ]); + priv->dreg =nft_parse_register (tb[NFTA_HASH_DREG ]);
Should we use nft_validate_register_load and nft_validate_register_store here to check the validity ?
Quoted 4 lines
net/netfilter/nft_hash.c new file +4
-0+ + len =ntohl (nla_get_be32 (tb[NFTA_HASH_LEN ])); +if (len ==0 || len >U8_MAX ) +return -EINVAL ;
Quoted 11 lines · Liping Zhang
Hi Laura,
2016-08-10 2:22 GMT+08:00 Laura Garcia Liebana <[email protected]>:
Quoted 8 lines
This patch adds a new hash expression, this provides jhash support but this can be extended to support for other hash functions.
The modulus and seed already comes embedded into this new expression.
Use case example:
meta mark set hash ip saddr mod 10
Quoted 15 lines
net/netfilter/nft_hash.c line 59
Quoted 11 lines
net/netfilter/nft_hash.c new file +11
-0+static int nft_hash_init (const struct nft_ctx *ctx, +const struct nft_expr *expr, +const struct nlattr *const tb[]) +{ +struct nft_hash *priv =nft_expr_priv (expr); +u32 len; + +if (!tb[NFTA_HASH_SREG ] || + !tb[NFTA_HASH_DREG ] || + !tb[NFTA_HASH_LEN ]) +return -EINVAL ;I think tb[NFTA_HASH_MODULUS] and tb[NFTA_HASH_SEED] should also be checked is NULL or not? :)
tb[NFTA_HASH_MODULUS] is not optional now so we can check it here, but tb[NFTA_HASH_SEED] is optional so we can check and if it's null, then assign 0 to the seed value.
Quoted 7 lines
net/netfilter/nft_hash.c line 62
Quoted 3 lines
net/netfilter/nft_hash.c new file +3
-0+ + priv->sreg =nft_parse_register (tb[NFTA_HASH_SREG ]); + priv->dreg =nft_parse_register (tb[NFTA_HASH_DREG ]);Should we use
nft_validate_register_loadandnft_validate_register_storehere to check the validity ?
Yes, I'll include that.
Thank you Liping.