diff options
author | Laura Garcia Liebana <nevola@gmail.com> | 2016-08-11 16:02:07 (GMT) |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-08-12 12:16:04 (GMT) |
commit | cb1b69b0b15b2897daeba8674c14c85a23a3347f (patch) | |
tree | 697f80cc7ac91f39cf5eeb2df4e50eeae695000c /net/netfilter | |
parent | 0ed6389c483dc77cdbdd48de0ca7ce41723dd667 (diff) | |
download | linux-cb1b69b0b15b2897daeba8674c14c85a23a3347f.tar.xz |
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
Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
-rw-r--r-- | net/netfilter/Kconfig | 6 | ||||
-rw-r--r-- | net/netfilter/Makefile | 1 | ||||
-rw-r--r-- | net/netfilter/nft_hash.c | 136 |
3 files changed, 143 insertions, 0 deletions
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index e5740e1..9cfaa00 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -563,6 +563,12 @@ 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 diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 101fb85..1106ccd 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -92,6 +92,7 @@ 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 diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c new file mode 100644 index 0000000..b82ff29 --- /dev/null +++ b/net/netfilter/nft_hash.c @@ -0,0 +1,136 @@ +/* + * Copyright (c) 2016 Laura Garcia <nevola@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/netlink.h> +#include <linux/netfilter.h> +#include <linux/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables_core.h> +#include <linux/jhash.h> + +struct nft_hash { + enum nft_registers sreg:8; + enum nft_registers dreg:8; + u8 len; + u32 modulus; + u32 seed; +}; + +static void nft_hash_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + struct nft_hash *priv = nft_expr_priv(expr); + const void *data = ®s->data[priv->sreg]; + + regs->data[priv->dreg] = + reciprocal_scale(jhash(data, priv->len, priv->seed), + priv->modulus); +} + +const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = { + [NFTA_HASH_SREG] = { .type = NLA_U32 }, + [NFTA_HASH_DREG] = { .type = NLA_U32 }, + [NFTA_HASH_LEN] = { .type = NLA_U32 }, + [NFTA_HASH_MODULUS] = { .type = NLA_U32 }, + [NFTA_HASH_SEED] = { .type = NLA_U32 }, +}; + +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] || + !tb[NFTA_HASH_SEED] || + !tb[NFTA_HASH_MODULUS]) + return -EINVAL; + + priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]); + priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]); + + len = ntohl(nla_get_be32(tb[NFTA_HASH_LEN])); + if (len == 0 || len > U8_MAX) + return -ERANGE; + + priv->len = len; + + priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS])); + if (priv->modulus <= 1) + return -ERANGE; + + priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED])); + + return nft_validate_register_load(priv->sreg, len) && + nft_validate_register_store(ctx, priv->dreg, NULL, + NFT_DATA_VALUE, sizeof(u32)); +} + +static int nft_hash_dump(struct sk_buff *skb, + const struct nft_expr *expr) +{ + const struct nft_hash *priv = nft_expr_priv(expr); + + if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg)) + goto nla_put_failure; + if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg)) + goto nla_put_failure; + if (nft_dump_register(skb, NFTA_HASH_LEN, priv->len)) + goto nla_put_failure; + if (nft_dump_register(skb, NFTA_HASH_MODULUS, priv->modulus)) + goto nla_put_failure; + if (nft_dump_register(skb, NFTA_HASH_SEED, priv->seed)) + goto nla_put_failure; + + return 0; + +nla_put_failure: + return -1; +} + +static struct nft_expr_type nft_hash_type; +static const struct nft_expr_ops nft_hash_ops = { + .type = &nft_hash_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_hash)), + .eval = nft_hash_eval, + .init = nft_hash_init, + .dump = nft_hash_dump, +}; + +static struct nft_expr_type nft_hash_type __read_mostly = { + .name = "hash", + .ops = &nft_hash_ops, + .policy = nft_hash_policy, + .maxattr = NFTA_HASH_MAX, + .owner = THIS_MODULE, +}; + +static int __init nft_hash_module_init(void) +{ + return nft_register_expr(&nft_hash_type); +} + +static void __exit nft_hash_module_exit(void) +{ + nft_unregister_expr(&nft_hash_type); +} + +module_init(nft_hash_module_init); +module_exit(nft_hash_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>"); +MODULE_ALIAS_NFT_EXPR("hash"); |