// SPDX-License-Identifier: GPL-2.0-only
|
/*
|
* Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
|
*/
|
|
#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_jhash {
|
u8 sreg;
|
u8 dreg;
|
u8 len;
|
bool autogen_seed:1;
|
u32 modulus;
|
u32 seed;
|
u32 offset;
|
};
|
|
static void nft_jhash_eval(const struct nft_expr *expr,
|
struct nft_regs *regs,
|
const struct nft_pktinfo *pkt)
|
{
|
struct nft_jhash *priv = nft_expr_priv(expr);
|
const void *data = ®s->data[priv->sreg];
|
u32 h;
|
|
h = reciprocal_scale(jhash(data, priv->len, priv->seed),
|
priv->modulus);
|
|
regs->data[priv->dreg] = h + priv->offset;
|
}
|
|
struct nft_symhash {
|
u8 dreg;
|
u32 modulus;
|
u32 offset;
|
};
|
|
static void nft_symhash_eval(const struct nft_expr *expr,
|
struct nft_regs *regs,
|
const struct nft_pktinfo *pkt)
|
{
|
struct nft_symhash *priv = nft_expr_priv(expr);
|
struct sk_buff *skb = pkt->skb;
|
u32 h;
|
|
h = reciprocal_scale(__skb_get_hash_symmetric(skb), priv->modulus);
|
|
regs->data[priv->dreg] = h + priv->offset;
|
}
|
|
static 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 },
|
[NFTA_HASH_OFFSET] = { .type = NLA_U32 },
|
[NFTA_HASH_TYPE] = { .type = NLA_U32 },
|
};
|
|
static int nft_jhash_init(const struct nft_ctx *ctx,
|
const struct nft_expr *expr,
|
const struct nlattr * const tb[])
|
{
|
struct nft_jhash *priv = nft_expr_priv(expr);
|
u32 len;
|
int err;
|
|
if (!tb[NFTA_HASH_SREG] ||
|
!tb[NFTA_HASH_DREG] ||
|
!tb[NFTA_HASH_LEN] ||
|
!tb[NFTA_HASH_MODULUS])
|
return -EINVAL;
|
|
if (tb[NFTA_HASH_OFFSET])
|
priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
|
|
err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
|
if (err < 0)
|
return err;
|
if (len == 0)
|
return -ERANGE;
|
|
priv->len = len;
|
|
err = nft_parse_register_load(tb[NFTA_HASH_SREG], &priv->sreg, len);
|
if (err < 0)
|
return err;
|
|
priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
|
if (priv->modulus < 1)
|
return -ERANGE;
|
|
if (priv->offset + priv->modulus - 1 < priv->offset)
|
return -EOVERFLOW;
|
|
if (tb[NFTA_HASH_SEED]) {
|
priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED]));
|
} else {
|
priv->autogen_seed = true;
|
get_random_bytes(&priv->seed, sizeof(priv->seed));
|
}
|
|
return nft_parse_register_store(ctx, tb[NFTA_HASH_DREG], &priv->dreg,
|
NULL, NFT_DATA_VALUE, sizeof(u32));
|
}
|
|
static int nft_symhash_init(const struct nft_ctx *ctx,
|
const struct nft_expr *expr,
|
const struct nlattr * const tb[])
|
{
|
struct nft_symhash *priv = nft_expr_priv(expr);
|
|
if (!tb[NFTA_HASH_DREG] ||
|
!tb[NFTA_HASH_MODULUS])
|
return -EINVAL;
|
|
if (tb[NFTA_HASH_OFFSET])
|
priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
|
|
priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
|
if (priv->modulus < 1)
|
return -ERANGE;
|
|
if (priv->offset + priv->modulus - 1 < priv->offset)
|
return -EOVERFLOW;
|
|
return nft_parse_register_store(ctx, tb[NFTA_HASH_DREG],
|
&priv->dreg, NULL, NFT_DATA_VALUE,
|
sizeof(u32));
|
}
|
|
static int nft_jhash_dump(struct sk_buff *skb,
|
const struct nft_expr *expr)
|
{
|
const struct nft_jhash *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 (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len)))
|
goto nla_put_failure;
|
if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
|
goto nla_put_failure;
|
if (!priv->autogen_seed &&
|
nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed)))
|
goto nla_put_failure;
|
if (priv->offset != 0)
|
if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
|
goto nla_put_failure;
|
if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_JENKINS)))
|
goto nla_put_failure;
|
return 0;
|
|
nla_put_failure:
|
return -1;
|
}
|
|
static int nft_symhash_dump(struct sk_buff *skb,
|
const struct nft_expr *expr)
|
{
|
const struct nft_symhash *priv = nft_expr_priv(expr);
|
|
if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
|
goto nla_put_failure;
|
if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
|
goto nla_put_failure;
|
if (priv->offset != 0)
|
if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
|
goto nla_put_failure;
|
if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_SYM)))
|
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_jhash_ops = {
|
.type = &nft_hash_type,
|
.size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
|
.eval = nft_jhash_eval,
|
.init = nft_jhash_init,
|
.dump = nft_jhash_dump,
|
};
|
|
static const struct nft_expr_ops nft_symhash_ops = {
|
.type = &nft_hash_type,
|
.size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
|
.eval = nft_symhash_eval,
|
.init = nft_symhash_init,
|
.dump = nft_symhash_dump,
|
};
|
|
static const struct nft_expr_ops *
|
nft_hash_select_ops(const struct nft_ctx *ctx,
|
const struct nlattr * const tb[])
|
{
|
u32 type;
|
|
if (!tb[NFTA_HASH_TYPE])
|
return &nft_jhash_ops;
|
|
type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE]));
|
switch (type) {
|
case NFT_HASH_SYM:
|
return &nft_symhash_ops;
|
case NFT_HASH_JENKINS:
|
return &nft_jhash_ops;
|
default:
|
break;
|
}
|
return ERR_PTR(-EOPNOTSUPP);
|
}
|
|
static struct nft_expr_type nft_hash_type __read_mostly = {
|
.name = "hash",
|
.select_ops = nft_hash_select_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");
|
MODULE_DESCRIPTION("Netfilter nftables hash module");
|
