Commit 39e6dea2 authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso

netfilter: nf_tables: add forward expression to the netdev family

You can use this to forward packets from ingress to the egress path of
the specified interface. This provides a fast path to bounce packets
from one interface to another specific destination interface.
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 502061f8
......@@ -983,6 +983,18 @@ enum nft_dup_attributes {
};
#define NFTA_DUP_MAX (__NFTA_DUP_MAX - 1)
/**
* enum nft_fwd_attributes - nf_tables fwd expression netlink attributes
*
* @NFTA_FWD_SREG_DEV: source register of output interface (NLA_U32: nft_register)
*/
enum nft_fwd_attributes {
NFTA_FWD_UNSPEC,
NFTA_FWD_SREG_DEV,
__NFTA_FWD_MAX
};
#define NFTA_FWD_MAX (__NFTA_FWD_MAX - 1)
/**
* enum nft_gen_attributes - nf_tables ruleset generation attributes
*
......
......@@ -577,6 +577,12 @@ config NFT_DUP_NETDEV
help
This option enables packet duplication for the "netdev" family.
config NFT_FWD_NETDEV
tristate "Netfilter nf_tables netdev packet forwarding support"
select NF_DUP_NETDEV
help
This option enables packet forwarding for the "netdev" family.
endif # NF_TABLES_NETDEV
endif # NF_TABLES
......
......@@ -95,6 +95,7 @@ obj-$(CONFIG_NFT_REDIR) += nft_redir.o
# nf_tables netdev
obj-$(CONFIG_NFT_DUP_NETDEV) += nft_dup_netdev.o
obj-$(CONFIG_NFT_FWD_NETDEV) += nft_fwd_netdev.o
# generic X tables
obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o
......
/*
* 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/nf_dup_netdev.h>
struct nft_fwd_netdev {
enum nft_registers sreg_dev:8;
};
static void nft_fwd_netdev_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_fwd_netdev *priv = nft_expr_priv(expr);
int oif = regs->data[priv->sreg_dev];
nf_dup_netdev_egress(pkt, oif);
regs->verdict.code = NF_DROP;
}
static const struct nla_policy nft_fwd_netdev_policy[NFTA_FWD_MAX + 1] = {
[NFTA_FWD_SREG_DEV] = { .type = NLA_U32 },
};
static int nft_fwd_netdev_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_fwd_netdev *priv = nft_expr_priv(expr);
if (tb[NFTA_FWD_SREG_DEV] == NULL)
return -EINVAL;
priv->sreg_dev = nft_parse_register(tb[NFTA_FWD_SREG_DEV]);
return nft_validate_register_load(priv->sreg_dev, sizeof(int));
}
static const struct nft_expr_ops nft_fwd_netdev_ingress_ops;
static int nft_fwd_netdev_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
struct nft_fwd_netdev *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_fwd_netdev_type;
static const struct nft_expr_ops nft_fwd_netdev_ops = {
.type = &nft_fwd_netdev_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_fwd_netdev)),
.eval = nft_fwd_netdev_eval,
.init = nft_fwd_netdev_init,
.dump = nft_fwd_netdev_dump,
};
static struct nft_expr_type nft_fwd_netdev_type __read_mostly = {
.family = NFPROTO_NETDEV,
.name = "fwd",
.ops = &nft_fwd_netdev_ops,
.policy = nft_fwd_netdev_policy,
.maxattr = NFTA_FWD_MAX,
.owner = THIS_MODULE,
};
static int __init nft_fwd_netdev_module_init(void)
{
return nft_register_expr(&nft_fwd_netdev_type);
}
static void __exit nft_fwd_netdev_module_exit(void)
{
nft_unregister_expr(&nft_fwd_netdev_type);
}
module_init(nft_fwd_netdev_module_init);
module_exit(nft_fwd_netdev_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_AF_EXPR(5, "fwd");
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