new file mode 100644
@@ -0,0 +1,14 @@
+#ifndef _NF_NAT_MASQUERADE_IPV4_H_
+#define _NF_NAT_MASQUERADE_IPV4_H_
+
+#include <net/netfilter/nf_nat.h>
+
+unsigned int
+nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum,
+ const struct nf_nat_range *range,
+ const struct net_device *out);
+
+void nf_nat_masquerade_ipv4_register_notifier(void);
+void nf_nat_masquerade_ipv4_unregister_notifier(void);
+
+#endif /*_NF_NAT_MASQUERADE_IPV4_H_ */
@@ -184,8 +184,15 @@ config NF_NAT_IPV4
if NF_NAT_IPV4
+config NF_NAT_MASQUERADE_IPV4
+ tristate "IPv4 masquerade support"
+ help
+ This is the kernel functionality to provide NAT in the masquerade
+ flavour (automatic source address selection).
+
config IP_NF_TARGET_MASQUERADE
tristate "MASQUERADE target support"
+ select NF_NAT_MASQUERADE_IPV4
default m if NETFILTER_ADVANCED=n
help
Masquerading is a special case of NAT: all outgoing connections are
@@ -27,6 +27,7 @@ obj-$(CONFIG_NF_LOG_IPV4) += nf_log_ipv4.o
obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o
obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
obj-$(CONFIG_NF_NAT_SNMP_BASIC) += nf_nat_snmp_basic.o
+obj-$(CONFIG_NF_NAT_MASQUERADE_IPV4) += nf_nat_masquerade_ipv4.o
# NAT protocols (nf_nat)
obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o
@@ -22,6 +22,7 @@
#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>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
@@ -46,103 +47,17 @@ static int masquerade_tg_check(const struct xt_tgchk_param *par)
static unsigned int
masquerade_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
- struct nf_conn *ct;
- struct nf_conn_nat *nat;
- enum ip_conntrack_info ctinfo;
- struct nf_nat_range newrange;
+ struct nf_nat_range range;
const struct nf_nat_ipv4_multi_range_compat *mr;
- const struct rtable *rt;
- __be32 newsrc, nh;
-
- NF_CT_ASSERT(par->hooknum == NF_INET_POST_ROUTING);
-
- ct = nf_ct_get(skb, &ctinfo);
- nat = nfct_nat(ct);
-
- NF_CT_ASSERT(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;
mr = par->targinfo;
- rt = skb_rtable(skb);
- nh = rt_nexthop(rt, ip_hdr(skb)->daddr);
- newsrc = inet_select_addr(par->out, nh, RT_SCOPE_UNIVERSE);
- if (!newsrc) {
- pr_info("%s ate my IP address\n", par->out->name);
- return NF_DROP;
- }
-
- nat->masq_index = par->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 = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS;
- newrange.min_addr.ip = newsrc;
- newrange.max_addr.ip = newsrc;
- newrange.min_proto = mr->range[0].min;
- newrange.max_proto = mr->range[0].max;
+ range.flags = mr->range[0].flags;
+ range.min_proto = mr->range[0].min;
+ range.max_proto = mr->range[0].max;
- /* Hand modified range to generic setup. */
- return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
+ return nf_nat_masquerade_ipv4(skb, par->hooknum, &range, par->out);
}
-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. */
- NF_CT_ASSERT(dev->ifindex != 0);
-
- nf_ct_iterate_cleanup(net, device_cmp,
- (void *)(long)dev->ifindex, 0, 0);
- }
-
- return NOTIFY_DONE;
-}
-
-static int masq_inet_event(struct notifier_block *this,
- unsigned long event,
- void *ptr)
-{
- struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev;
- struct netdev_notifier_info info;
-
- netdev_notifier_info_init(&info, dev);
- return masq_device_event(this, event, &info);
-}
-
-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 struct xt_target masquerade_tg_reg __read_mostly = {
.name = "MASQUERADE",
.family = NFPROTO_IPV4,
@@ -160,12 +75,8 @@ static int __init masquerade_tg_init(void)
ret = xt_register_target(&masquerade_tg_reg);
- if (ret == 0) {
- /* Register for device down reports */
- register_netdevice_notifier(&masq_dev_notifier);
- /* Register IP address change reports */
- register_inetaddr_notifier(&masq_inet_notifier);
- }
+ if (ret == 0)
+ nf_nat_masquerade_ipv4_register_notifier();
return ret;
}
@@ -173,8 +84,7 @@ static int __init masquerade_tg_init(void)
static void __exit masquerade_tg_exit(void)
{
xt_unregister_target(&masquerade_tg_reg);
- unregister_netdevice_notifier(&masq_dev_notifier);
- unregister_inetaddr_notifier(&masq_inet_notifier);
+ nf_nat_masquerade_ipv4_unregister_notifier();
}
module_init(masquerade_tg_init);
new file mode 100644
@@ -0,0 +1,153 @@
+/* (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/module.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_range *range,
+ const struct net_device *out)
+{
+ struct nf_conn *ct;
+ struct nf_conn_nat *nat;
+ enum ip_conntrack_info ctinfo;
+ struct nf_nat_range newrange;
+ const struct rtable *rt;
+ __be32 newsrc, nh;
+
+ NF_CT_ASSERT(hooknum == NF_INET_POST_ROUTING);
+
+ ct = nf_ct_get(skb, &ctinfo);
+ nat = nfct_nat(ct);
+
+ NF_CT_ASSERT(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->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.
+ */
+ NF_CT_ASSERT(dev->ifindex != 0);
+
+ nf_ct_iterate_cleanup(net, device_cmp,
+ (void *)(long)dev->ifindex, 0, 0);
+ }
+
+ return NOTIFY_DONE;
+}
+
+static int masq_inet_event(struct notifier_block *this,
+ unsigned long event,
+ void *ptr)
+{
+ struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev;
+ struct netdev_notifier_info info;
+
+ netdev_notifier_info_init(&info, dev);
+ return masq_device_event(this, event, &info);
+}
+
+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 atomic_t masquerade_notifier_refcount = ATOMIC_INIT(0);
+
+void nf_nat_masquerade_ipv4_register_notifier(void)
+{
+ /* check if the notifier was already set */
+ if (atomic_inc_return(&masquerade_notifier_refcount) > 1)
+ return;
+
+ /* Register for device down reports */
+ register_netdevice_notifier(&masq_dev_notifier);
+ /* Register IP address change reports */
+ register_inetaddr_notifier(&masq_inet_notifier);
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_register_notifier);
+
+void nf_nat_masquerade_ipv4_unregister_notifier(void)
+{
+ /* check if the notifier still has clients */
+ if (atomic_dec_return(&masquerade_notifier_refcount) > 0)
+ return;
+
+ unregister_netdevice_notifier(&masq_dev_notifier);
+ unregister_inetaddr_notifier(&masq_inet_notifier);
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_unregister_notifier);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");