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/*
* Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
*
* 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_core.h>
#include <net/netfilter/nf_tables.h>
struct nft_range_expr {
struct nft_data data_from;
struct nft_data data_to;
enum nft_registers sreg:8;
u8 len;
enum nft_range_ops op:8;
};
static void nft_range_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_range_expr *priv = nft_expr_priv(expr);
int d1, d2;
d1 = memcmp(®s->data[priv->sreg], &priv->data_from, priv->len);
d2 = memcmp(®s->data[priv->sreg], &priv->data_to, priv->len);
switch (priv->op) {
case NFT_RANGE_EQ:
if (d1 < 0 || d2 > 0)
regs->verdict.code = NFT_BREAK;
break;
case NFT_RANGE_NEQ:
if (d1 >= 0 && d2 <= 0)
regs->verdict.code = NFT_BREAK;
break;
}
}
static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = {
[NFTA_RANGE_SREG] = { .type = NLA_U32 },
[NFTA_RANGE_OP] = { .type = NLA_U32 },
[NFTA_RANGE_FROM_DATA] = { .type = NLA_NESTED },
[NFTA_RANGE_TO_DATA] = { .type = NLA_NESTED },
};
static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_range_expr *priv = nft_expr_priv(expr);
struct nft_data_desc desc_from, desc_to;
int err;
u32 op;
if (!tb[NFTA_RANGE_SREG] ||
!tb[NFTA_RANGE_OP] ||
!tb[NFTA_RANGE_FROM_DATA] ||
!tb[NFTA_RANGE_TO_DATA])
return -EINVAL;
err = nft_data_init(NULL, &priv->data_from, sizeof(priv->data_from),
&desc_from, tb[NFTA_RANGE_FROM_DATA]);
if (err < 0)
return err;
err = nft_data_init(NULL, &priv->data_to, sizeof(priv->data_to),
&desc_to, tb[NFTA_RANGE_TO_DATA]);
if (err < 0)
goto err1;
if (desc_from.len != desc_to.len) {
err = -EINVAL;
goto err2;
}
priv->sreg = nft_parse_register(tb[NFTA_RANGE_SREG]);
err = nft_validate_register_load(priv->sreg, desc_from.len);
if (err < 0)
goto err2;
err = nft_parse_u32_check(tb[NFTA_RANGE_OP], U8_MAX, &op);
if (err < 0)
goto err2;
switch (op) {
case NFT_RANGE_EQ:
case NFT_RANGE_NEQ:
break;
default:
err = -EINVAL;
goto err2;
}
priv->op = op;
priv->len = desc_from.len;
return 0;
err2:
nft_data_uninit(&priv->data_to, desc_to.type);
err1:
nft_data_uninit(&priv->data_from, desc_from.type);
return err;
}
static int nft_range_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_range_expr *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_RANGE_SREG, priv->sreg))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_RANGE_OP, htonl(priv->op)))
goto nla_put_failure;
if (nft_data_dump(skb, NFTA_RANGE_FROM_DATA, &priv->data_from,
NFT_DATA_VALUE, priv->len) < 0 ||
nft_data_dump(skb, NFTA_RANGE_TO_DATA, &priv->data_to,
NFT_DATA_VALUE, priv->len) < 0)
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static const struct nft_expr_ops nft_range_ops = {
.type = &nft_range_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_range_expr)),
.eval = nft_range_eval,
.init = nft_range_init,
.dump = nft_range_dump,
};
struct nft_expr_type nft_range_type __read_mostly = {
.name = "range",
.ops = &nft_range_ops,
.policy = nft_range_policy,
.maxattr = NFTA_RANGE_MAX,
.owner = THIS_MODULE,
};
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