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>

3 files changed, 2 insertions, 202 deletions

diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 80f72cc5ca8d..db05a835748a 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -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
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index fd7122e0e2c9..ddeb35ab8bdb 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -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
diff --git a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
deleted file mode 100644
index 41327bb99093..000000000000
--- a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
+++ /dev/null
@@ -1,196 +0,0 @@
-/* (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.
- */
-
-#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 <net/netfilter/ipv4/nf_nat_masquerade.h>
-
-unsigned int
-nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum,
-		       const struct nf_nat_range2 *range,
-		       const struct net_device *out)
-{
-	struct nf_conn *ct;
-	struct nf_conn_nat *nat;
-	enum ip_conntrack_info ctinfo;
-	struct nf_nat_range2 newrange;
-	const struct rtable *rt;
-	__be32 newsrc, nh;
-
-	WARN_ON(hooknum != NF_INET_POST_ROUTING);
-
-	ct = nf_ct_get(skb, &ctinfo);
-
-	WARN_ON(!(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
-			 ctinfo == IP_CT_RELATED_REPLY)));
-
-	/* Source address is 0.0.0.0 - locally generated packet that is
-	 * probably not supposed to be masqueraded.
-	 */
-	if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip == 0)
-		return NF_ACCEPT;
-
-	rt = skb_rtable(skb);
-	nh = rt_nexthop(rt, ip_hdr(skb)->daddr);
-	newsrc = inet_select_addr(out, nh, RT_SCOPE_UNIVERSE);
-	if (!newsrc) {
-		pr_info("%s ate my IP address\n", out->name);
-		return NF_DROP;
-	}
-
-	nat = nf_ct_nat_ext_add(ct);
-	if (nat)
-		nat->masq_index = out->ifindex;
-
-	/* Transfer from original range. */
-	memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
-	memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
-	newrange.flags       = range->flags | NF_NAT_RANGE_MAP_IPS;
-	newrange.min_addr.ip = newsrc;
-	newrange.max_addr.ip = newsrc;
-	newrange.min_proto   = range->min_proto;
-	newrange.max_proto   = range->max_proto;
-
-	/* Hand modified range to generic setup. */
-	return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
-}
-EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4);
-
-static int device_cmp(struct nf_conn *i, void *ifindex)
-{
-	const struct nf_conn_nat *nat = nfct_nat(i);
-
-	if (!nat)
-		return 0;
-	if (nf_ct_l3num(i) != NFPROTO_IPV4)
-		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) {
-		/* Device was downed.  Search entire table for
-		 * 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);
-	}
-
-	return NOTIFY_DONE;
-}
-
-static int inet_cmp(struct nf_conn *ct, void *ptr)
-{
-	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
-	struct net_device *dev = ifa->ifa_dev->dev;
-	struct nf_conntrack_tuple *tuple;
-
-	if (!device_cmp(ct, (void *)(long)dev->ifindex))
-		return 0;
-
-	tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
-
-	return ifa->ifa_address == tuple->dst.u3.ip;
-}
-
-static int masq_inet_event(struct notifier_block *this,
-			   unsigned long event,
-			   void *ptr)
-{
-	struct in_device *idev = ((struct in_ifaddr *)ptr)->ifa_dev;
-	struct net *net = dev_net(idev->dev);
-
-	/* The masq_dev_notifier will catch the case of the device going
-	 * down.  So if the inetdev is dead and being destroyed we have
-	 * no work to do.  Otherwise this is an individual address removal
-	 * and we have to perform the flush.
-	 */
-	if (idev->dead)
-		return NOTIFY_DONE;
-
-	if (event == NETDEV_DOWN)
-		nf_ct_iterate_cleanup_net(net, inet_cmp, ptr, 0, 0);
-
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block masq_dev_notifier = {
-	.notifier_call	= masq_device_event,
-};
-
-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;
-
-	mutex_lock(&masq_mutex);
-	/* check if the notifier was already set */
-	if (++masq_refcnt > 1)
-		goto out_unlock;
-
-	/* Register for device down reports */
-	ret = register_netdevice_notifier(&masq_dev_notifier);
-	if (ret)
-		goto err_dec;
-	/* Register IP address change reports */
-	ret = register_inetaddr_notifier(&masq_inet_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_ipv4_register_notifier);
-
-void nf_nat_masquerade_ipv4_unregister_notifier(void)
-{
-	mutex_lock(&masq_mutex);
-	/* check if the notifier still has clients */
-	if (--masq_refcnt > 0)
-		goto out_unlock;
-
-	unregister_netdevice_notifier(&masq_dev_notifier);
-	unregister_inetaddr_notifier(&masq_inet_notifier);
-out_unlock:
-	mutex_unlock(&masq_mutex);
-}
-EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_unregister_notifier);