From: Florian Westphal <fw@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/net/netfilter/nf_nat.h | 6 +-
net/ipv4/netfilter/Kconfig | 7 +-
net/ipv4/netfilter/Makefile | 1 -
net/ipv4/netfilter/nf_nat_masquerade_ipv4.c | 196 ---------------
net/ipv6/netfilter/Kconfig | 11 +-
net/ipv6/netfilter/Makefile | 1 -
net/ipv6/netfilter/nf_nat_masquerade_ipv6.c | 240 ------------------
net/netfilter/Kconfig | 3 +
net/netfilter/Makefile | 1 +
net/netfilter/nf_nat_masquerade.c | 362 ++++++++++++++++++++++++++++
10 files changed, 372 insertions(+), 456 deletions(-)
delete mode 100644 net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
delete mode 100644 net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
create mode 100644 net/netfilter/nf_nat_masquerade.c
diff --git a/include/net/netfilter/nf_nat.h b/include/net/netfilter/nf_nat.h
index 8aff77cafb8b..e53b4f9b8b44 100644
--- a/include/net/netfilter/nf_nat.h
+++ b/include/net/netfilter/nf_nat.h
@@ -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;
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@xxxxxxxxxxxxx>
- *
- * 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);
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@xxxxxxxxx>
- *
- * 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);
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index fefd63a243f2..5a753cec005b 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -431,6 +431,9 @@ config NF_NAT_TFTP
config NF_NAT_REDIRECT
bool
+config NF_NAT_MASQUERADE
+ bool
+
config NETFILTER_SYNPROXY
tristate
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index e66067befa42..c7910706f8dd 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -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
diff --git a/net/netfilter/nf_nat_masquerade.c b/net/netfilter/nf_nat_masquerade.c
new file mode 100644
index 000000000000..86fa4dcc63c5
--- /dev/null
+++ b/net/netfilter/nf_nat_masquerade.c
@@ -0,0 +1,362 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/inetdevice.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.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,
+ 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;
+ 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.
+ */
+
+ 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,
+};
+
+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);
+
+#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
--
2.11.0
