nft_byteorder.c
// 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 <asm/unaligned.h>
#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_byteorder {
u8 sreg;
u8 dreg;
enum nft_byteorder_ops op:8;
u8 len;
u8 size;
};
void nft_byteorder_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_byteorder *priv = nft_expr_priv(expr);
u32 *src = ®s->data[priv->sreg];
u32 *dst = ®s->data[priv->dreg];
union { u32 u32; u16 u16; } *s, *d;
unsigned int i;
s = (void *)src;
d = (void *)dst;
switch (priv->size) {
case 8: {
u64 src64;
switch (priv->op) {
case NFT_BYTEORDER_NTOH:
for (i = 0; i < priv->len / 8; i++) {
src64 = nft_reg_load64(&src[i]);
nft_reg_store64(&dst[i],
be64_to_cpu((__force __be64)src64));
}
break;
case NFT_BYTEORDER_HTON:
for (i = 0; i < priv->len / 8; i++) {
src64 = (__force __u64)
cpu_to_be64(nft_reg_load64(&src[i]));
nft_reg_store64(&dst[i], src64);
}
break;
}
break;
}
case 4:
switch (priv->op) {
case NFT_BYTEORDER_NTOH:
for (i = 0; i < priv->len / 4; i++)
d[i].u32 = ntohl((__force __be32)s[i].u32);
break;
case NFT_BYTEORDER_HTON:
for (i = 0; i < priv->len / 4; i++)
d[i].u32 = (__force __u32)htonl(s[i].u32);
break;
}
break;
case 2:
switch (priv->op) {
case NFT_BYTEORDER_NTOH:
for (i = 0; i < priv->len / 2; i++)
d[i].u16 = ntohs((__force __be16)s[i].u16);
break;
case NFT_BYTEORDER_HTON:
for (i = 0; i < priv->len / 2; i++)
d[i].u16 = (__force __u16)htons(s[i].u16);
break;
}
break;
}
}
static const struct nla_policy nft_byteorder_policy[NFTA_BYTEORDER_MAX + 1] = {
[NFTA_BYTEORDER_SREG] = { .type = NLA_U32 },
[NFTA_BYTEORDER_DREG] = { .type = NLA_U32 },
[NFTA_BYTEORDER_OP] = { .type = NLA_U32 },
[NFTA_BYTEORDER_LEN] = { .type = NLA_U32 },
[NFTA_BYTEORDER_SIZE] = { .type = NLA_U32 },
};
static int nft_byteorder_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_byteorder *priv = nft_expr_priv(expr);
u32 size, len;
int err;
if (tb[NFTA_BYTEORDER_SREG] == NULL ||
tb[NFTA_BYTEORDER_DREG] == NULL ||
tb[NFTA_BYTEORDER_LEN] == NULL ||
tb[NFTA_BYTEORDER_SIZE] == NULL ||
tb[NFTA_BYTEORDER_OP] == NULL)
return -EINVAL;
priv->op = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_OP]));
switch (priv->op) {
case NFT_BYTEORDER_NTOH:
case NFT_BYTEORDER_HTON:
break;
default:
return -EINVAL;
}
err = nft_parse_u32_check(tb[NFTA_BYTEORDER_SIZE], U8_MAX, &size);
if (err < 0)
return err;
priv->size = size;
switch (priv->size) {
case 2:
case 4:
case 8:
break;
default:
return -EINVAL;
}
err = nft_parse_u32_check(tb[NFTA_BYTEORDER_LEN], U8_MAX, &len);
if (err < 0)
return err;
priv->len = len;
err = nft_parse_register_load(tb[NFTA_BYTEORDER_SREG], &priv->sreg,
priv->len);
if (err < 0)
return err;
return nft_parse_register_store(ctx, tb[NFTA_BYTEORDER_DREG],
&priv->dreg, NULL, NFT_DATA_VALUE,
priv->len);
}
static int nft_byteorder_dump(struct sk_buff *skb,
const struct nft_expr *expr, bool reset)
{
const struct nft_byteorder *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_BYTEORDER_SREG, priv->sreg))
goto nla_put_failure;
if (nft_dump_register(skb, NFTA_BYTEORDER_DREG, priv->dreg))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_BYTEORDER_OP, htonl(priv->op)))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_BYTEORDER_LEN, htonl(priv->len)))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_BYTEORDER_SIZE, htonl(priv->size)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static bool nft_byteorder_reduce(struct nft_regs_track *track,
const struct nft_expr *expr)
{
struct nft_byteorder *priv = nft_expr_priv(expr);
nft_reg_track_cancel(track, priv->dreg, priv->len);
return false;
}
static const struct nft_expr_ops nft_byteorder_ops = {
.type = &nft_byteorder_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_byteorder)),
.eval = nft_byteorder_eval,
.init = nft_byteorder_init,
.dump = nft_byteorder_dump,
.reduce = nft_byteorder_reduce,
};
struct nft_expr_type nft_byteorder_type __read_mostly = {
.name = "byteorder",
.ops = &nft_byteorder_ops,
.policy = nft_byteorder_policy,
.maxattr = NFTA_BYTEORDER_MAX,
.owner = THIS_MODULE,
};