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netfilter: nf_tables: add new expression nft_redir

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This new expression provides NAT in the redirect flavour, which is to
redirect packets to local machine.

Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Arturo Borrero 2014-10-17 12:39:09 +02:00 • committed by Pablo Neira Ayuso
commit e9105f1bea
11 changed files with 319 additions and 0 deletions
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21
include/net/netfilter/nft_redir.h Normal file
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@ -0,0 +1,21 @@
#ifndef _NFT_REDIR_H_
#define _NFT_REDIR_H_
struct nft_redir {
enum nft_registers sreg_proto_min:8;
enum nft_registers sreg_proto_max:8;
u16 flags;
};
extern const struct nla_policy nft_redir_policy[];
int nft_redir_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[]);
int nft_redir_dump(struct sk_buff *skb, const struct nft_expr *expr);
int nft_redir_validate(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nft_data **data);
#endif /* _NFT_REDIR_H_ */

16
include/uapi/linux/netfilter/nf_tables.h
View file

@ -837,6 +837,22 @@ enum nft_masq_attributes {
};
#define NFTA_MASQ_MAX (__NFTA_MASQ_MAX - 1)
/**
* enum nft_redir_attributes - nf_tables redirect expression netlink attributes
*
* @NFTA_REDIR_REG_PROTO_MIN: source register of proto range start (NLA_U32: nft_registers)
* @NFTA_REDIR_REG_PROTO_MAX: source register of proto range end (NLA_U32: nft_registers)
* @NFTA_REDIR_FLAGS: NAT flags (see NF_NAT_RANGE_* in linux/netfilter/nf_nat.h) (NLA_U32)
*/
enum nft_redir_attributes {
NFTA_REDIR_UNSPEC,
NFTA_REDIR_REG_PROTO_MIN,
NFTA_REDIR_REG_PROTO_MAX,
NFTA_REDIR_FLAGS,
__NFTA_REDIR_MAX
};
#define NFTA_REDIR_MAX (__NFTA_REDIR_MAX - 1)
/**
* enum nft_gen_attributes - nf_tables ruleset generation attributes
*

9
net/ipv4/netfilter/Kconfig
View file

@ -119,6 +119,15 @@ config NFT_MASQ_IPV4
This is the expression that provides IPv4 masquerading support for
nf_tables.
config NFT_REDIR_IPV4
tristate "IPv4 redirect support for nf_tables"
depends on NF_TABLES_IPV4
depends on NFT_REDIR
select NF_NAT_REDIRECT_IPV4
help
This is the expression that provides IPv4 redirect support for
nf_tables.
config NF_NAT_SNMP_BASIC
tristate "Basic SNMP-ALG support"
depends on NF_CONNTRACK_SNMP

1
net/ipv4/netfilter/Makefile
View file

@ -41,6 +41,7 @@ obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV4) += nft_chain_route_ipv4.o
obj-$(CONFIG_NFT_CHAIN_NAT_IPV4) += nft_chain_nat_ipv4.o
obj-$(CONFIG_NFT_REJECT_IPV4) += nft_reject_ipv4.o
obj-$(CONFIG_NFT_MASQ_IPV4) += nft_masq_ipv4.o
obj-$(CONFIG_NFT_REDIR_IPV4) += nft_redir_ipv4.o
obj-$(CONFIG_NF_TABLES_ARP) += nf_tables_arp.o
# generic IP tables

77
net/ipv4/netfilter/nft_redir_ipv4.c Normal file
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@ -0,0 +1,77 @@
/*
* Copyright (c) 2014 Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
*
* 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_nat.h>
#include <net/netfilter/ipv4/nf_nat_redirect.h>
#include <net/netfilter/nft_redir.h>
static void nft_redir_ipv4_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt)
{
struct nft_redir *priv = nft_expr_priv(expr);
struct nf_nat_ipv4_multi_range_compat mr;
unsigned int verdict;
memset(&mr, 0, sizeof(mr));
if (priv->sreg_proto_min) {
mr.range[0].min.all = (__force __be16)
data[priv->sreg_proto_min].data[0];
mr.range[0].max.all = (__force __be16)
data[priv->sreg_proto_max].data[0];
mr.range[0].flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
}
mr.range[0].flags |= priv->flags;
verdict = nf_nat_redirect_ipv4(pkt->skb, &mr, pkt->ops->hooknum);
data[NFT_REG_VERDICT].verdict = verdict;
}
static struct nft_expr_type nft_redir_ipv4_type;
static const struct nft_expr_ops nft_redir_ipv4_ops = {
.type = &nft_redir_ipv4_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_redir)),
.eval = nft_redir_ipv4_eval,
.init = nft_redir_init,
.dump = nft_redir_dump,
.validate = nft_redir_validate,
};
static struct nft_expr_type nft_redir_ipv4_type __read_mostly = {
.family = NFPROTO_IPV4,
.name = "redir",
.ops = &nft_redir_ipv4_ops,
.policy = nft_redir_policy,
.maxattr = NFTA_REDIR_MAX,
.owner = THIS_MODULE,
};
static int __init nft_redir_ipv4_module_init(void)
{
return nft_register_expr(&nft_redir_ipv4_type);
}
static void __exit nft_redir_ipv4_module_exit(void)
{
nft_unregister_expr(&nft_redir_ipv4_type);
}
module_init(nft_redir_ipv4_module_init);
module_exit(nft_redir_ipv4_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>");
MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "redir");

9
net/ipv6/netfilter/Kconfig
View file

@ -97,6 +97,15 @@ config NFT_MASQ_IPV6
This is the expression that provides IPv4 masquerading support for
nf_tables.
config NFT_REDIR_IPV6
tristate "IPv6 redirect support for nf_tables"
depends on NF_TABLES_IPV6
depends on NFT_REDIR
select NF_NAT_REDIRECT_IPV6
help
This is the expression that provides IPv4 redirect support for
nf_tables.
endif # NF_NAT_IPV6
config IP6_NF_IPTABLES

1
net/ipv6/netfilter/Makefile
View file

@ -37,6 +37,7 @@ obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV6) += nft_chain_route_ipv6.o
obj-$(CONFIG_NFT_CHAIN_NAT_IPV6) += nft_chain_nat_ipv6.o
obj-$(CONFIG_NFT_REJECT_IPV6) += nft_reject_ipv6.o
obj-$(CONFIG_NFT_MASQ_IPV6) += nft_masq_ipv6.o
obj-$(CONFIG_NFT_REDIR_IPV6) += nft_redir_ipv6.o
# matches
obj-$(CONFIG_IP6_NF_MATCH_AH) += ip6t_ah.o

77
net/ipv6/netfilter/nft_redir_ipv6.c Normal file
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@ -0,0 +1,77 @@
/*
* Copyright (c) 2014 Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
*
* 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_nat.h>
#include <net/netfilter/nft_redir.h>
#include <net/netfilter/ipv6/nf_nat_redirect.h>
static void nft_redir_ipv6_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt)
{
struct nft_redir *priv = nft_expr_priv(expr);
struct nf_nat_range range;
unsigned int verdict;
memset(&range, 0, sizeof(range));
if (priv->sreg_proto_min) {
range.min_proto.all = (__force __be16)
data[priv->sreg_proto_min].data[0];
range.max_proto.all = (__force __be16)
data[priv->sreg_proto_max].data[0];
range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
}
range.flags |= priv->flags;
verdict = nf_nat_redirect_ipv6(pkt->skb, &range, pkt->ops->hooknum);
data[NFT_REG_VERDICT].verdict = verdict;
}
static struct nft_expr_type nft_redir_ipv6_type;
static const struct nft_expr_ops nft_redir_ipv6_ops = {
.type = &nft_redir_ipv6_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_redir)),
.eval = nft_redir_ipv6_eval,
.init = nft_redir_init,
.dump = nft_redir_dump,
.validate = nft_redir_validate,
};
static struct nft_expr_type nft_redir_ipv6_type __read_mostly = {
.family = NFPROTO_IPV6,
.name = "redir",
.ops = &nft_redir_ipv6_ops,
.policy = nft_redir_policy,
.maxattr = NFTA_REDIR_MAX,
.owner = THIS_MODULE,
};
static int __init nft_redir_ipv6_module_init(void)
{
return nft_register_expr(&nft_redir_ipv6_type);
}
static void __exit nft_redir_ipv6_module_exit(void)
{
nft_unregister_expr(&nft_redir_ipv6_type);
}
module_init(nft_redir_ipv6_module_init);
module_exit(nft_redir_ipv6_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>");
MODULE_ALIAS_NFT_AF_EXPR(AF_INET6, "redir");

9
net/netfilter/Kconfig
View file

@ -505,6 +505,15 @@ config NFT_MASQ
This option adds the "masquerade" expression that you can use
to perform NAT in the masquerade flavour.
config NFT_REDIR
depends on NF_TABLES
depends on NF_CONNTRACK
depends on NF_NAT
tristate "Netfilter nf_tables redirect support"
help
This options adds the "redirect" expression that you can use
to perform NAT in the redirect flavour.
config NFT_NAT
depends on NF_TABLES
depends on NF_CONNTRACK

1
net/netfilter/Makefile
View file

@ -88,6 +88,7 @@ obj-$(CONFIG_NFT_HASH) += nft_hash.o
obj-$(CONFIG_NFT_COUNTER) += nft_counter.o
obj-$(CONFIG_NFT_LOG) += nft_log.o
obj-$(CONFIG_NFT_MASQ) += nft_masq.o
obj-$(CONFIG_NFT_REDIR) += nft_redir.o
# generic X tables
obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o

98
net/netfilter/nft_redir.c Normal file
View file

@ -0,0 +1,98 @@
/*
* Copyright (c) 2014 Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
*
* 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_nat.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nft_redir.h>
const struct nla_policy nft_redir_policy[NFTA_REDIR_MAX + 1] = {
[NFTA_REDIR_REG_PROTO_MIN] = { .type = NLA_U32 },
[NFTA_REDIR_REG_PROTO_MAX] = { .type = NLA_U32 },
[NFTA_REDIR_FLAGS] = { .type = NLA_U32 },
};
EXPORT_SYMBOL_GPL(nft_redir_policy);
int nft_redir_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_redir *priv = nft_expr_priv(expr);
u32 nla_be32;
int err;
err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
if (err < 0)
return err;
if (tb[NFTA_REDIR_REG_PROTO_MIN]) {
nla_be32 = nla_get_be32(tb[NFTA_REDIR_REG_PROTO_MIN]);
priv->sreg_proto_min = ntohl(nla_be32);
err = nft_validate_input_register(priv->sreg_proto_min);
if (err < 0)
return err;
if (tb[NFTA_REDIR_REG_PROTO_MAX]) {
nla_be32 = nla_get_be32(tb[NFTA_REDIR_REG_PROTO_MAX]);
priv->sreg_proto_max = ntohl(nla_be32);
err = nft_validate_input_register(priv->sreg_proto_max);
if (err < 0)
return err;
} else {
priv->sreg_proto_max = priv->sreg_proto_min;
}
}
if (tb[NFTA_REDIR_FLAGS]) {
priv->flags = ntohl(nla_get_be32(tb[NFTA_REDIR_FLAGS]));
if (priv->flags & ~NF_NAT_RANGE_MASK)
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(nft_redir_init);
int nft_redir_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_redir *priv = nft_expr_priv(expr);
if (priv->sreg_proto_min) {
if (nla_put_be32(skb, NFTA_REDIR_REG_PROTO_MIN,
htonl(priv->sreg_proto_min)))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_REDIR_REG_PROTO_MAX,
htonl(priv->sreg_proto_max)))
goto nla_put_failure;
}
if (priv->flags != 0 &&
nla_put_be32(skb, NFTA_REDIR_FLAGS, htonl(priv->flags)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
EXPORT_SYMBOL_GPL(nft_redir_dump);
int nft_redir_validate(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nft_data **data)
{
return nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
}
EXPORT_SYMBOL_GPL(nft_redir_validate);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>");