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, 250 deletions

diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index 339d0762b027..f57fc99e9a04 100644
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -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
diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index 9ea43d5256e0..a7b18d13e056 100644
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -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
diff --git a/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c b/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
deleted file mode 100644
index fd313b726263..000000000000
--- a/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
+++ /dev/null
@@ -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);