nft_bitwise.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
*
* 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>
#include <net/netfilter/nf_tables_offload.h>
struct nft_bitwise {
enum nft_registers sreg:8;
enum nft_registers dreg:8;
u8 len;
struct nft_data mask;
struct nft_data xor;
};
void nft_bitwise_eval(const struct nft_expr *expr,
struct nft_regs *regs, const struct nft_pktinfo *pkt)
{
const struct nft_bitwise *priv = nft_expr_priv(expr);
const u32 *src = ®s->data[priv->sreg];
u32 *dst = ®s->data[priv->dreg];
unsigned int i;
for (i = 0; i < DIV_ROUND_UP(priv->len, 4); i++)
dst[i] = (src[i] & priv->mask.data[i]) ^ priv->xor.data[i];
}
static const struct nla_policy nft_bitwise_policy[NFTA_BITWISE_MAX + 1] = {
[NFTA_BITWISE_SREG] = { .type = NLA_U32 },
[NFTA_BITWISE_DREG] = { .type = NLA_U32 },
[NFTA_BITWISE_LEN] = { .type = NLA_U32 },
[NFTA_BITWISE_MASK] = { .type = NLA_NESTED },
[NFTA_BITWISE_XOR] = { .type = NLA_NESTED },
};
static int nft_bitwise_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_bitwise *priv = nft_expr_priv(expr);
struct nft_data_desc d1, d2;
u32 len;
int err;
if (tb[NFTA_BITWISE_SREG] == NULL ||
tb[NFTA_BITWISE_DREG] == NULL ||
tb[NFTA_BITWISE_LEN] == NULL ||
tb[NFTA_BITWISE_MASK] == NULL ||
tb[NFTA_BITWISE_XOR] == NULL)
return -EINVAL;
err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
if (err < 0)
return err;
priv->len = len;
priv->sreg = nft_parse_register(tb[NFTA_BITWISE_SREG]);
err = nft_validate_register_load(priv->sreg, priv->len);
if (err < 0)
return err;
priv->dreg = nft_parse_register(tb[NFTA_BITWISE_DREG]);
err = nft_validate_register_store(ctx, priv->dreg, NULL,
NFT_DATA_VALUE, priv->len);
if (err < 0)
return err;
err = nft_data_init(NULL, &priv->mask, sizeof(priv->mask), &d1,
tb[NFTA_BITWISE_MASK]);
if (err < 0)
return err;
if (d1.type != NFT_DATA_VALUE || d1.len != priv->len) {
err = -EINVAL;
goto err1;
}
err = nft_data_init(NULL, &priv->xor, sizeof(priv->xor), &d2,
tb[NFTA_BITWISE_XOR]);
if (err < 0)
goto err1;
if (d2.type != NFT_DATA_VALUE || d2.len != priv->len) {
err = -EINVAL;
goto err2;
}
return 0;
err2:
nft_data_release(&priv->xor, d2.type);
err1:
nft_data_release(&priv->mask, d1.type);
return err;
}
static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_bitwise *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
goto nla_put_failure;
if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len)))
goto nla_put_failure;
if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask,
NFT_DATA_VALUE, priv->len) < 0)
goto nla_put_failure;
if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor,
NFT_DATA_VALUE, priv->len) < 0)
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_data zero;
static int nft_bitwise_offload(struct nft_offload_ctx *ctx,
struct nft_flow_rule *flow,
const struct nft_expr *expr)
{
const struct nft_bitwise *priv = nft_expr_priv(expr);
struct nft_offload_reg *reg = &ctx->regs[priv->dreg];
if (memcmp(&priv->xor, &zero, sizeof(priv->xor)) ||
priv->sreg != priv->dreg || priv->len != reg->len)
return -EOPNOTSUPP;
memcpy(®->mask, &priv->mask, sizeof(priv->mask));
return 0;
}
static const struct nft_expr_ops nft_bitwise_ops = {
.type = &nft_bitwise_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_bitwise)),
.eval = nft_bitwise_eval,
.init = nft_bitwise_init,
.dump = nft_bitwise_dump,
.offload = nft_bitwise_offload,
};
struct nft_expr_type nft_bitwise_type __read_mostly = {
.name = "bitwise",
.ops = &nft_bitwise_ops,
.policy = nft_bitwise_policy,
.maxattr = NFTA_BITWISE_MAX,
.owner = THIS_MODULE,
};