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/*
* 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>
static void nft_payload_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_payload *priv = nft_expr_priv(expr);
const struct sk_buff *skb = pkt->skb;
u32 *dest = ®s->data[priv->dreg];
int offset;
switch (priv->base) {
case NFT_PAYLOAD_LL_HEADER:
if (!skb_mac_header_was_set(skb))
goto err;
offset = skb_mac_header(skb) - skb->data;
break;
case NFT_PAYLOAD_NETWORK_HEADER:
offset = skb_network_offset(skb);
break;
case NFT_PAYLOAD_TRANSPORT_HEADER:
offset = pkt->xt.thoff;
break;
default:
BUG();
}
offset += priv->offset;
dest[priv->len / NFT_REG32_SIZE] = 0;
if (skb_copy_bits(skb, offset, dest, priv->len) < 0)
goto err;
return;
err:
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_payload_policy[NFTA_PAYLOAD_MAX + 1] = {
[NFTA_PAYLOAD_DREG] = { .type = NLA_U32 },
[NFTA_PAYLOAD_BASE] = { .type = NLA_U32 },
[NFTA_PAYLOAD_OFFSET] = { .type = NLA_U32 },
[NFTA_PAYLOAD_LEN] = { .type = NLA_U32 },
};
static int nft_payload_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_payload *priv = nft_expr_priv(expr);
priv->base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
priv->len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
priv->dreg = nft_parse_register(tb[NFTA_PAYLOAD_DREG]);
return nft_validate_register_store(ctx, priv->dreg, NULL,
NFT_DATA_VALUE, priv->len);
}
static int nft_payload_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_payload *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_PAYLOAD_DREG, priv->dreg) ||
nla_put_be32(skb, NFTA_PAYLOAD_BASE, htonl(priv->base)) ||
nla_put_be32(skb, NFTA_PAYLOAD_OFFSET, htonl(priv->offset)) ||
nla_put_be32(skb, NFTA_PAYLOAD_LEN, htonl(priv->len)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_payload_type;
static const struct nft_expr_ops nft_payload_ops = {
.type = &nft_payload_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_payload)),
.eval = nft_payload_eval,
.init = nft_payload_init,
.dump = nft_payload_dump,
};
const struct nft_expr_ops nft_payload_fast_ops = {
.type = &nft_payload_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_payload)),
.eval = nft_payload_eval,
.init = nft_payload_init,
.dump = nft_payload_dump,
};
static const struct nft_expr_ops *
nft_payload_select_ops(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
enum nft_payload_bases base;
unsigned int offset, len;
if (tb[NFTA_PAYLOAD_DREG] == NULL ||
tb[NFTA_PAYLOAD_BASE] == NULL ||
tb[NFTA_PAYLOAD_OFFSET] == NULL ||
tb[NFTA_PAYLOAD_LEN] == NULL)
return ERR_PTR(-EINVAL);
base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
switch (base) {
case NFT_PAYLOAD_LL_HEADER:
case NFT_PAYLOAD_NETWORK_HEADER:
case NFT_PAYLOAD_TRANSPORT_HEADER:
break;
default:
return ERR_PTR(-EOPNOTSUPP);
}
offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
if (len <= 4 && is_power_of_2(len) && IS_ALIGNED(offset, len) &&
base != NFT_PAYLOAD_LL_HEADER)
return &nft_payload_fast_ops;
else
return &nft_payload_ops;
}
static struct nft_expr_type nft_payload_type __read_mostly = {
.name = "payload",
.select_ops = nft_payload_select_ops,
.policy = nft_payload_policy,
.maxattr = NFTA_PAYLOAD_MAX,
.owner = THIS_MODULE,
};
int __init nft_payload_module_init(void)
{
return nft_register_expr(&nft_payload_type);
}
void nft_payload_module_exit(void)
{
nft_unregister_expr(&nft_payload_type);
}
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