alistair23-linux/net/netfilter/nft_immediate.c
Patrick McHardy 49499c3e6e netfilter: nf_tables: switch registers to 32 bit addressing
Switch the nf_tables registers from 128 bit addressing to 32 bit
addressing to support so called concatenations, where multiple values
can be concatenated over multiple registers for O(1) exact matches of
multiple dimensions using sets.

The old register values are mapped to areas of 128 bits for compatibility.
When dumping register numbers, values are expressed using the old values
if they refer to the beginning of a 128 bit area for compatibility.

To support concatenations, register loads of less than a full 32 bit
value need to be padded. This mainly affects the payload and exthdr
expressions, which both unconditionally zero the last word before
copying the data.

Userspace fully passes the testsuite using both old and new register
addressing.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-04-13 17:17:29 +02:00

131 lines
3.4 KiB
C

/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
*
* 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.
*
* Development of this code funded by Astaro AG (http://www.astaro.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_core.h>
#include <net/netfilter/nf_tables.h>
struct nft_immediate_expr {
struct nft_data data;
enum nft_registers dreg:8;
u8 dlen;
};
static void nft_immediate_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_immediate_expr *priv = nft_expr_priv(expr);
nft_data_copy(&regs->data[priv->dreg], &priv->data, priv->dlen);
}
static const struct nla_policy nft_immediate_policy[NFTA_IMMEDIATE_MAX + 1] = {
[NFTA_IMMEDIATE_DREG] = { .type = NLA_U32 },
[NFTA_IMMEDIATE_DATA] = { .type = NLA_NESTED },
};
static int nft_immediate_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_immediate_expr *priv = nft_expr_priv(expr);
struct nft_data_desc desc;
int err;
if (tb[NFTA_IMMEDIATE_DREG] == NULL ||
tb[NFTA_IMMEDIATE_DATA] == NULL)
return -EINVAL;
err = nft_data_init(ctx, &priv->data, &desc, tb[NFTA_IMMEDIATE_DATA]);
if (err < 0)
return err;
priv->dlen = desc.len;
priv->dreg = nft_parse_register(tb[NFTA_IMMEDIATE_DREG]);
err = nft_validate_register_store(ctx, priv->dreg, &priv->data,
desc.type, desc.len);
if (err < 0)
goto err1;
return 0;
err1:
nft_data_uninit(&priv->data, desc.type);
return err;
}
static void nft_immediate_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
const struct nft_immediate_expr *priv = nft_expr_priv(expr);
return nft_data_uninit(&priv->data, nft_dreg_to_type(priv->dreg));
}
static int nft_immediate_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_immediate_expr *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_IMMEDIATE_DREG, priv->dreg))
goto nla_put_failure;
return nft_data_dump(skb, NFTA_IMMEDIATE_DATA, &priv->data,
nft_dreg_to_type(priv->dreg), priv->dlen);
nla_put_failure:
return -1;
}
static int nft_immediate_validate(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nft_data **data)
{
const struct nft_immediate_expr *priv = nft_expr_priv(expr);
if (priv->dreg == NFT_REG_VERDICT)
*data = &priv->data;
return 0;
}
static struct nft_expr_type nft_imm_type;
static const struct nft_expr_ops nft_imm_ops = {
.type = &nft_imm_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_immediate_expr)),
.eval = nft_immediate_eval,
.init = nft_immediate_init,
.destroy = nft_immediate_destroy,
.dump = nft_immediate_dump,
.validate = nft_immediate_validate,
};
static struct nft_expr_type nft_imm_type __read_mostly = {
.name = "immediate",
.ops = &nft_imm_ops,
.policy = nft_immediate_policy,
.maxattr = NFTA_IMMEDIATE_MAX,
.owner = THIS_MODULE,
};
int __init nft_immediate_module_init(void)
{
return nft_register_expr(&nft_imm_type);
}
void nft_immediate_module_exit(void)
{
nft_unregister_expr(&nft_imm_type);
}