nft_dup_ipv4.c
/*
* Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
*
* 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.
*/
#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>
#include <net/netfilter/ipv4/nf_dup_ipv4.h>
struct nft_dup_ipv4 {
enum nft_registers sreg_addr:8;
enum nft_registers sreg_dev:8;
};
static void nft_dup_ipv4_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
struct in_addr gw = {
.s_addr = (__force __be32)regs->data[priv->sreg_addr],
};
int oif = priv->sreg_dev ? regs->data[priv->sreg_dev] : -1;
nf_dup_ipv4(nft_net(pkt), pkt->skb, nft_hook(pkt), &gw, oif);
}
static int nft_dup_ipv4_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
int err;
if (tb[NFTA_DUP_SREG_ADDR] == NULL)
return -EINVAL;
priv->sreg_addr = nft_parse_register(tb[NFTA_DUP_SREG_ADDR]);
err = nft_validate_register_load(priv->sreg_addr, sizeof(struct in_addr));
if (err < 0)
return err;
if (tb[NFTA_DUP_SREG_DEV] != NULL) {
priv->sreg_dev = nft_parse_register(tb[NFTA_DUP_SREG_DEV]);
return nft_validate_register_load(priv->sreg_dev, sizeof(int));
}
return 0;
}
static int nft_dup_ipv4_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_DUP_SREG_ADDR, priv->sreg_addr))
goto nla_put_failure;
if (priv->sreg_dev &&
nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_dup_ipv4_type;
static const struct nft_expr_ops nft_dup_ipv4_ops = {
.type = &nft_dup_ipv4_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_dup_ipv4)),
.eval = nft_dup_ipv4_eval,
.init = nft_dup_ipv4_init,
.dump = nft_dup_ipv4_dump,
};
static const struct nla_policy nft_dup_ipv4_policy[NFTA_DUP_MAX + 1] = {
[NFTA_DUP_SREG_ADDR] = { .type = NLA_U32 },
[NFTA_DUP_SREG_DEV] = { .type = NLA_U32 },
};
static struct nft_expr_type nft_dup_ipv4_type __read_mostly = {
.family = NFPROTO_IPV4,
.name = "dup",
.ops = &nft_dup_ipv4_ops,
.policy = nft_dup_ipv4_policy,
.maxattr = NFTA_DUP_MAX,
.owner = THIS_MODULE,
};
static int __init nft_dup_ipv4_module_init(void)
{
return nft_register_expr(&nft_dup_ipv4_type);
}
static void __exit nft_dup_ipv4_module_exit(void)
{
nft_unregister_expr(&nft_dup_ipv4_type);
}
module_init(nft_dup_ipv4_module_init);
module_exit(nft_dup_ipv4_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "dup");