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netfilter: nat: merge ipv4 and ipv6 masquerade functionality 

Before:
   text	   data	    bss	    dec	    hex	filename
  13916	   1412	   4128	  19456	   4c00	nf_nat.ko
   4510	    968	      4	   5482	   156a	nf_nat_ipv4.ko
   5146	    944	      8	   6098	   17d2	nf_nat_ipv6.ko

After:
   text	   data	    bss	    dec	    hex	filename
  16566	   1576	   4136	  22278	   5706	nf_nat.ko
   3187	    844	      0	   4031	    fbf	nf_nat_ipv4.ko
   3598	    844	      0	   4442	   115a	nf_nat_ipv6.ko

... so no drastic changes in combined size.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2019-02-19 17:38:19 +01:00 committed by Pablo Neira Ayuso
parent d824548dae
commit d1aca8ab31
9 changed files with 197 additions and 281 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/net/netfilter/nf_nat.h
View File

@ -31,8 +31,7 @@ struct nf_conn;
/* The structure embedded in the conntrack structure. */
struct nf_conn_nat {
union nf_conntrack_nat_help help;
#if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV4) || \
IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV6)
#if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE)
int masq_index;
#endif
};
@ -61,8 +60,7 @@ static inline bool nf_nat_oif_changed(unsigned int hooknum,
struct nf_conn_nat *nat,
const struct net_device *out)
{
#if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV4) || \
IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV6)
#if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE)
return nat && nat->masq_index && hooknum == NF_INET_POST_ROUTING &&
CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL &&
nat->masq_index != out->ifindex;

7
net/ipv4/netfilter/Kconfig
View File

@ -106,9 +106,6 @@ config NF_NAT_IPV4
if NF_NAT_IPV4
config NF_NAT_MASQUERADE_IPV4
bool
if NF_TABLES
config NFT_CHAIN_NAT_IPV4
depends on NF_TABLES_IPV4
@ -123,7 +120,7 @@ config NFT_MASQ_IPV4
tristate "IPv4 masquerading support for nf_tables"
depends on NF_TABLES_IPV4
depends on NFT_MASQ
select NF_NAT_MASQUERADE_IPV4
select NF_NAT_MASQUERADE
help
This is the expression that provides IPv4 masquerading support for
nf_tables.
@ -276,7 +273,7 @@ if IP_NF_NAT
config IP_NF_TARGET_MASQUERADE
tristate "MASQUERADE target support"
select NF_NAT_MASQUERADE_IPV4
select NF_NAT_MASQUERADE
default m if NETFILTER_ADVANCED=n
help
Masquerading is a special case of NAT: all outgoing connections are

1
net/ipv4/netfilter/Makefile
View File

@ -4,7 +4,6 @@
#
nf_nat_ipv4-y := nf_nat_l3proto_ipv4.o
nf_nat_ipv4-$(CONFIG_NF_NAT_MASQUERADE_IPV4) += nf_nat_masquerade_ipv4.o
obj-$(CONFIG_NF_NAT_IPV4) += nf_nat_ipv4.o
# defrag

11
net/ipv6/netfilter/Kconfig
View File

@ -44,7 +44,7 @@ config NFT_CHAIN_NAT_IPV6
config NFT_MASQ_IPV6
tristate "IPv6 masquerade support for nf_tables"
depends on NFT_MASQ
select NF_NAT_MASQUERADE_IPV6
select NF_NAT_MASQUERADE
help
This is the expression that provides IPv4 masquerading support for
nf_tables.
@ -116,13 +116,6 @@ config NF_NAT_IPV6
forms of full Network Address Port Translation. This can be
controlled by iptables or nft.
if NF_NAT_IPV6
config NF_NAT_MASQUERADE_IPV6
bool
endif # NF_NAT_IPV6
config IP6_NF_IPTABLES
tristate "IP6 tables support (required for filtering)"
depends on INET && IPV6
@ -324,7 +317,7 @@ if IP6_NF_NAT
config IP6_NF_TARGET_MASQUERADE
tristate "MASQUERADE target support"
select NF_NAT_MASQUERADE_IPV6
select NF_NAT_MASQUERADE
help
Masquerading is a special case of NAT: all outgoing connections are
changed to seem to come from a particular interface's address, and

1
net/ipv6/netfilter/Makefile
View File

@ -12,7 +12,6 @@ obj-$(CONFIG_IP6_NF_SECURITY) += ip6table_security.o
obj-$(CONFIG_IP6_NF_NAT) += ip6table_nat.o
nf_nat_ipv6-y := nf_nat_l3proto_ipv6.o
nf_nat_ipv6-$(CONFIG_NF_NAT_MASQUERADE_IPV6) += nf_nat_masquerade_ipv6.o
obj-$(CONFIG_NF_NAT_IPV6) += nf_nat_ipv6.o
# defrag

240
net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
View File

@ -1,240 +0,0 @@
/*
* Copyright (c) 2011 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.
*
* Based on Rusty Russell's IPv6 MASQUERADE target. Development of IPv6
* NAT funded by Astaro.
*/
#include <linux/kernel.h>
#include <linux/atomic.h>
#include <linux/netdevice.h>
#include <linux/ipv6.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/nf_nat.h>
#include <net/addrconf.h>
#include <net/ipv6.h>
#include <net/netfilter/ipv6/nf_nat_masquerade.h>
#define MAX_WORK_COUNT 16
static atomic_t v6_worker_count;
static int
nat_ipv6_dev_get_saddr(struct net *net, const struct net_device *dev,
const struct in6_addr *daddr, unsigned int srcprefs,
struct in6_addr *saddr)
{
#ifdef CONFIG_IPV6_MODULE
const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
if (!v6_ops)
return -EHOSTUNREACH;
return v6_ops->dev_get_saddr(net, dev, daddr, srcprefs, saddr);
#else
return ipv6_dev_get_saddr(net, dev, daddr, srcprefs, saddr);
#endif
}
unsigned int
nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
const struct net_device *out)
{
enum ip_conntrack_info ctinfo;
struct nf_conn_nat *nat;
struct in6_addr src;
struct nf_conn *ct;
struct nf_nat_range2 newrange;
ct = nf_ct_get(skb, &ctinfo);
WARN_ON(!(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
ctinfo == IP_CT_RELATED_REPLY)));
if (nat_ipv6_dev_get_saddr(nf_ct_net(ct), out,
&ipv6_hdr(skb)->daddr, 0, &src) < 0)
return NF_DROP;
nat = nf_ct_nat_ext_add(ct);
if (nat)
nat->masq_index = out->ifindex;
newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
newrange.min_addr.in6 = src;
newrange.max_addr.in6 = src;
newrange.min_proto = range->min_proto;
newrange.max_proto = range->max_proto;
return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
}
EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6);
static int device_cmp(struct nf_conn *ct, void *ifindex)
{
const struct nf_conn_nat *nat = nfct_nat(ct);
if (!nat)
return 0;
if (nf_ct_l3num(ct) != NFPROTO_IPV6)
return 0;
return nat->masq_index == (int)(long)ifindex;
}
static int masq_device_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
const struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct net *net = dev_net(dev);
if (event == NETDEV_DOWN)
nf_ct_iterate_cleanup_net(net, device_cmp,
(void *)(long)dev->ifindex, 0, 0);
return NOTIFY_DONE;
}
static struct notifier_block masq_dev_notifier = {
.notifier_call = masq_device_event,
};
struct masq_dev_work {
struct work_struct work;
struct net *net;
struct in6_addr addr;
int ifindex;
};
static int inet_cmp(struct nf_conn *ct, void *work)
{
struct masq_dev_work *w = (struct masq_dev_work *)work;
struct nf_conntrack_tuple *tuple;
if (!device_cmp(ct, (void *)(long)w->ifindex))
return 0;
tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
return ipv6_addr_equal(&w->addr, &tuple->dst.u3.in6);
}
static void iterate_cleanup_work(struct work_struct *work)
{
struct masq_dev_work *w;
w = container_of(work, struct masq_dev_work, work);
nf_ct_iterate_cleanup_net(w->net, inet_cmp, (void *)w, 0, 0);
put_net(w->net);
kfree(w);
atomic_dec(&v6_worker_count);
module_put(THIS_MODULE);
}
/* ipv6 inet notifier is an atomic notifier, i.e. we cannot
* schedule.
*
* Unfortunately, nf_ct_iterate_cleanup_net can run for a long
* time if there are lots of conntracks and the system
* handles high softirq load, so it frequently calls cond_resched
* while iterating the conntrack table.
*
* So we defer nf_ct_iterate_cleanup_net walk to the system workqueue.
*
* As we can have 'a lot' of inet_events (depending on amount
* of ipv6 addresses being deleted), we also need to add an upper
* limit to the number of queued work items.
*/
static int masq_inet6_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct inet6_ifaddr *ifa = ptr;
const struct net_device *dev;
struct masq_dev_work *w;
struct net *net;
if (event != NETDEV_DOWN ||
atomic_read(&v6_worker_count) >= MAX_WORK_COUNT)
return NOTIFY_DONE;
dev = ifa->idev->dev;
net = maybe_get_net(dev_net(dev));
if (!net)
return NOTIFY_DONE;
if (!try_module_get(THIS_MODULE))
goto err_module;
w = kmalloc(sizeof(*w), GFP_ATOMIC);
if (w) {
atomic_inc(&v6_worker_count);
INIT_WORK(&w->work, iterate_cleanup_work);
w->ifindex = dev->ifindex;
w->net = net;
w->addr = ifa->addr;
schedule_work(&w->work);
return NOTIFY_DONE;
}
module_put(THIS_MODULE);
err_module:
put_net(net);
return NOTIFY_DONE;
}
static struct notifier_block masq_inet6_notifier = {
.notifier_call = masq_inet6_event,
};
static int masq_refcnt;
static DEFINE_MUTEX(masq_mutex);
int nf_nat_masquerade_ipv6_register_notifier(void)
{
int ret = 0;
mutex_lock(&masq_mutex);
/* check if the notifier is already set */
if (++masq_refcnt > 1)
goto out_unlock;
ret = register_netdevice_notifier(&masq_dev_notifier);
if (ret)
goto err_dec;
ret = register_inet6addr_notifier(&masq_inet6_notifier);
if (ret)
goto err_unregister;
mutex_unlock(&masq_mutex);
return ret;
err_unregister:
unregister_netdevice_notifier(&masq_dev_notifier);
err_dec:
masq_refcnt--;
out_unlock:
mutex_unlock(&masq_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_register_notifier);
void nf_nat_masquerade_ipv6_unregister_notifier(void)
{
mutex_lock(&masq_mutex);
/* check if the notifier still has clients */
if (--masq_refcnt > 0)
goto out_unlock;
unregister_inet6addr_notifier(&masq_inet6_notifier);
unregister_netdevice_notifier(&masq_dev_notifier);
out_unlock:
mutex_unlock(&masq_mutex);
}
EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_unregister_notifier);

3
net/netfilter/Kconfig
View File

@ -431,6 +431,9 @@ config NF_NAT_TFTP
config NF_NAT_REDIRECT
bool
config NF_NAT_MASQUERADE
bool
config NETFILTER_SYNPROXY
tristate

1
net/netfilter/Makefile
View File

@ -56,6 +56,7 @@ obj-$(CONFIG_NF_LOG_NETDEV) += nf_log_netdev.o
obj-$(CONFIG_NF_NAT) += nf_nat.o
nf_nat-$(CONFIG_NF_NAT_REDIRECT) += nf_nat_redirect.o
nf_nat-$(CONFIG_NF_NAT_MASQUERADE) += nf_nat_masquerade.o
# NAT helpers
obj-$(CONFIG_NF_NAT_AMANDA) += nf_nat_amanda.o

208
net/ipv4/netfilter/nf_nat_masquerade_ipv4.c → net/netfilter/nf_nat_masquerade.c
View File

@ -1,25 +1,17 @@
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@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.
*/
// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/inetdevice.h>
#include <linux/ip.h>
#include <linux/timer.h>
#include <linux/netfilter.h>
#include <net/protocol.h>
#include <net/ip.h>
#include <net/checksum.h>
#include <net/route.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter/x_tables.h>
#include <net/netfilter/nf_nat.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/ipv4/nf_nat_masquerade.h>
#include <net/netfilter/ipv6/nf_nat_masquerade.h>
static DEFINE_MUTEX(masq_mutex);
static unsigned int masq_refcnt __read_mostly;
unsigned int
nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum,
@ -78,8 +70,6 @@ static int device_cmp(struct nf_conn *i, void *ifindex)
if (!nat)
return 0;
if (nf_ct_l3num(i) != NFPROTO_IPV4)
return 0;
return nat->masq_index == (int)(long)ifindex;
}
@ -95,7 +85,6 @@ static int masq_device_event(struct notifier_block *this,
* conntracks which were associated with that device,
* and forget them.
*/
WARN_ON(dev->ifindex == 0);
nf_ct_iterate_cleanup_net(net, device_cmp,
(void *)(long)dev->ifindex, 0, 0);
@ -147,9 +136,6 @@ static struct notifier_block masq_inet_notifier = {
.notifier_call = masq_inet_event,
};
static int masq_refcnt;
static DEFINE_MUTEX(masq_mutex);
int nf_nat_masquerade_ipv4_register_notifier(void)
{
int ret = 0;
@ -194,3 +180,183 @@ out_unlock:
mutex_unlock(&masq_mutex);
}
EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_unregister_notifier);
#if IS_ENABLED(CONFIG_IPV6)
static atomic_t v6_worker_count __read_mostly;
static int
nat_ipv6_dev_get_saddr(struct net *net, const struct net_device *dev,
const struct in6_addr *daddr, unsigned int srcprefs,
struct in6_addr *saddr)
{
#ifdef CONFIG_IPV6_MODULE
const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
if (!v6_ops)
return -EHOSTUNREACH;
return v6_ops->dev_get_saddr(net, dev, daddr, srcprefs, saddr);
#else
return ipv6_dev_get_saddr(net, dev, daddr, srcprefs, saddr);
#endif
}
unsigned int
nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
const struct net_device *out)
{
enum ip_conntrack_info ctinfo;
struct nf_conn_nat *nat;
struct in6_addr src;
struct nf_conn *ct;
struct nf_nat_range2 newrange;
ct = nf_ct_get(skb, &ctinfo);
WARN_ON(!(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
ctinfo == IP_CT_RELATED_REPLY)));
if (nat_ipv6_dev_get_saddr(nf_ct_net(ct), out,
&ipv6_hdr(skb)->daddr, 0, &src) < 0)
return NF_DROP;
nat = nf_ct_nat_ext_add(ct);
if (nat)
nat->masq_index = out->ifindex;
newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
newrange.min_addr.in6 = src;
newrange.max_addr.in6 = src;
newrange.min_proto = range->min_proto;
newrange.max_proto = range->max_proto;
return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
}
EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6);
struct masq_dev_work {
struct work_struct work;
struct net *net;
struct in6_addr addr;
int ifindex;
};
static int inet6_cmp(struct nf_conn *ct, void *work)
{
struct masq_dev_work *w = (struct masq_dev_work *)work;
struct nf_conntrack_tuple *tuple;
if (!device_cmp(ct, (void *)(long)w->ifindex))
return 0;
tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
return ipv6_addr_equal(&w->addr, &tuple->dst.u3.in6);
}
static void iterate_cleanup_work(struct work_struct *work)
{
struct masq_dev_work *w;
w = container_of(work, struct masq_dev_work, work);
nf_ct_iterate_cleanup_net(w->net, inet6_cmp, (void *)w, 0, 0);
put_net(w->net);
kfree(w);
atomic_dec(&v6_worker_count);
module_put(THIS_MODULE);
}
/* atomic notifier; can't call nf_ct_iterate_cleanup_net (it can sleep).
*
* Defer it to the system workqueue.
*
* As we can have 'a lot' of inet_events (depending on amount of ipv6
* addresses being deleted), we also need to limit work item queue.
*/
static int masq_inet6_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct inet6_ifaddr *ifa = ptr;
const struct net_device *dev;
struct masq_dev_work *w;
struct net *net;
if (event != NETDEV_DOWN || atomic_read(&v6_worker_count) >= 16)
return NOTIFY_DONE;
dev = ifa->idev->dev;
net = maybe_get_net(dev_net(dev));
if (!net)
return NOTIFY_DONE;
if (!try_module_get(THIS_MODULE))
goto err_module;
w = kmalloc(sizeof(*w), GFP_ATOMIC);
if (w) {
atomic_inc(&v6_worker_count);
INIT_WORK(&w->work, iterate_cleanup_work);
w->ifindex = dev->ifindex;
w->net = net;
w->addr = ifa->addr;
schedule_work(&w->work);
return NOTIFY_DONE;
}
module_put(THIS_MODULE);
err_module:
put_net(net);
return NOTIFY_DONE;
}
static struct notifier_block masq_inet6_notifier = {
.notifier_call = masq_inet6_event,
};
int nf_nat_masquerade_ipv6_register_notifier(void)
{
int ret = 0;
mutex_lock(&masq_mutex);
/* check if the notifier is already set */
if (++masq_refcnt > 1)
goto out_unlock;
ret = register_netdevice_notifier(&masq_dev_notifier);
if (ret)
goto err_dec;
ret = register_inet6addr_notifier(&masq_inet6_notifier);
if (ret)
goto err_unregister;
mutex_unlock(&masq_mutex);
return ret;
err_unregister:
unregister_netdevice_notifier(&masq_dev_notifier);
err_dec:
masq_refcnt--;
out_unlock:
mutex_unlock(&masq_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_register_notifier);
void nf_nat_masquerade_ipv6_unregister_notifier(void)
{
mutex_lock(&masq_mutex);
/* check if the notifier still has clients */
if (--masq_refcnt > 0)
goto out_unlock;
unregister_inet6addr_notifier(&masq_inet6_notifier);
unregister_netdevice_notifier(&masq_dev_notifier);
out_unlock:
mutex_unlock(&masq_mutex);
}
EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_unregister_notifier);
#endif