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/*
* Copyright (c) 2008 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.h>
// FIXME:
#include <net/ipv6.h>
struct nft_exthdr {
u8 type;
u8 offset;
u8 len;
enum nft_registers dreg:8;
};
static void nft_exthdr_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_exthdr *priv = nft_expr_priv(expr);
u32 *dest = ®s->data[priv->dreg];
unsigned int offset = 0;
int err;
err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
if (err < 0)
goto err;
offset += priv->offset;
dest[priv->len / NFT_REG32_SIZE] = 0;
if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
goto err;
return;
err:
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
[NFTA_EXTHDR_DREG] = { .type = NLA_U32 },
[NFTA_EXTHDR_TYPE] = { .type = NLA_U8 },
[NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 },
[NFTA_EXTHDR_LEN] = { .type = NLA_U32 },
};
static int nft_exthdr_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_exthdr *priv = nft_expr_priv(expr);
u32 offset, len;
if (tb[NFTA_EXTHDR_DREG] == NULL ||
tb[NFTA_EXTHDR_TYPE] == NULL ||
tb[NFTA_EXTHDR_OFFSET] == NULL ||
tb[NFTA_EXTHDR_LEN] == NULL)
return -EINVAL;
offset = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OFFSET]));
len = ntohl(nla_get_be32(tb[NFTA_EXTHDR_LEN]));
if (offset > U8_MAX || len > U8_MAX)
return -ERANGE;
priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
priv->offset = offset;
priv->len = len;
priv->dreg = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
return nft_validate_register_store(ctx, priv->dreg, NULL,
NFT_DATA_VALUE, priv->len);
}
static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_exthdr *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg))
goto nla_put_failure;
if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_exthdr_type;
static const struct nft_expr_ops nft_exthdr_ops = {
.type = &nft_exthdr_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
.eval = nft_exthdr_eval,
.init = nft_exthdr_init,
.dump = nft_exthdr_dump,
};
static struct nft_expr_type nft_exthdr_type __read_mostly = {
.name = "exthdr",
.ops = &nft_exthdr_ops,
.policy = nft_exthdr_policy,
.maxattr = NFTA_EXTHDR_MAX,
.owner = THIS_MODULE,
};
static int __init nft_exthdr_module_init(void)
{
return nft_register_expr(&nft_exthdr_type);
}
static void __exit nft_exthdr_module_exit(void)
{
nft_unregister_expr(&nft_exthdr_type);
}
module_init(nft_exthdr_module_init);
module_exit(nft_exthdr_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_EXPR("exthdr");
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