netfilter: ip6tables: add MASQUERADE target

Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ip6tables: add MASQUERADE target
Signed-off-by: Patrick McHardy <kaber@trash.net>
Patrick McHardy · Pablo Neira Ayuso
1 parent 58a317f106
Showing 7 changed files with 155 additions and 4 deletions Side-by-side Diff
include/net/addrconf.h
include/net/netfilter/nf_nat.h
net/ipv4/netfilter/ipt_MASQUERADE.c
net/ipv6/addrconf.c
net/ipv6/netfilter/Kconfig
net/ipv6/netfilter/Makefile
net/ipv6/netfilter/ip6t_MASQUERADE.c
@@ -78,7 +78,7 @@
 						 int strict);
  
 extern int			ipv6_dev_get_saddr(struct net *net,
-					       struct net_device *dev,
+					       const struct net_device *dev,
 					       const struct in6_addr *daddr,
 					       unsigned int srcprefs,
 					       struct in6_addr *saddr);
@@ -43,7 +43,9 @@
 	struct nf_conn *ct;
 	union nf_conntrack_nat_help help;
 #if defined(CONFIG_IP_NF_TARGET_MASQUERADE) || \
-    defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE)
+    defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE) || \
+    defined(CONFIG_IP6_NF_TARGET_MASQUERADE) || \
+    defined(CONFIG_IP6_NF_TARGET_MASQUERADE_MODULE)
 	int masq_index;
 #endif
 };
@@ -99,7 +99,8 @@
  
 	if (!nat)
 		return 0;
-
+	if (nf_ct_l3num(i) != NFPROTO_IPV4)
+		return 0;
 	return nat->masq_index == (int)(long)ifindex;
 }
  
@@ -1093,7 +1093,7 @@
 	return ret;
 }
  
-int ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
+int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
 		       const struct in6_addr *daddr, unsigned int prefs,
 		       struct in6_addr *saddr)
 {
@@ -144,6 +144,18 @@
 	(e.g. when running oldconfig). It selects
 	CONFIG_NETFILTER_XT_TARGET_HL.
  
+config IP6_NF_TARGET_MASQUERADE
+	tristate "MASQUERADE target support"
+	depends on NF_NAT_IPV6
+	help
+	  Masquerading is a special case of NAT: all outgoing connections are
+	  changed to seem to come from a particular interface's address, and
+	  if the interface goes down, those connections are lost.  This is
+	  only useful for dialup accounts with dynamic IP address (ie. your IP
+	  address will be different on next dialup).
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 config IP6_NF_FILTER
 	tristate "Packet filtering"
 	default m if NETFILTER_ADVANCED=n
@@ -34,5 +34,6 @@
 obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o
  
 # targets
+obj-$(CONFIG_IP6_NF_TARGET_MASQUERADE) += ip6t_MASQUERADE.o
 obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o
+/*
+ * 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/module.h>
+#include <linux/netdevice.h>
+#include <linux/ipv6.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/netfilter/x_tables.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/addrconf.h>
+#include <net/ipv6.h>
+
+static unsigned int
+masquerade_tg6(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	const struct nf_nat_range *range = par->targinfo;
+	enum ip_conntrack_info ctinfo;
+	struct in6_addr src;
+	struct nf_conn *ct;
+	struct nf_nat_range newrange;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
+			    ctinfo == IP_CT_RELATED_REPLY));
+
+	if (ipv6_dev_get_saddr(dev_net(par->out), par->out,
+			       &ipv6_hdr(skb)->daddr, 0, &src) < 0)
+		return NF_DROP;
+
+	nfct_nat(ct)->masq_index = par->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);
+}
+
+static int masquerade_tg6_checkentry(const struct xt_tgchk_param *par)
+{
+	const struct nf_nat_range *range = par->targinfo;
+
+	if (range->flags & NF_NAT_RANGE_MAP_IPS)
+		return -EINVAL;
+	return 0;
+}
+
+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 = ptr;
+	struct net *net = dev_net(dev);
+
+	if (event == NETDEV_DOWN)
+		nf_ct_iterate_cleanup(net, device_cmp,
+				      (void *)(long)dev->ifindex);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block masq_dev_notifier = {
+	.notifier_call	= masq_device_event,
+};
+
+static int masq_inet_event(struct notifier_block *this,
+			   unsigned long event, void *ptr)
+{
+	struct inet6_ifaddr *ifa = ptr;
+
+	return masq_device_event(this, event, ifa->idev->dev);
+}
+
+static struct notifier_block masq_inet_notifier = {
+	.notifier_call	= masq_inet_event,
+};
+
+static struct xt_target masquerade_tg6_reg __read_mostly = {
+	.name		= "MASQUERADE",
+	.family		= NFPROTO_IPV6,
+	.checkentry	= masquerade_tg6_checkentry,
+	.target		= masquerade_tg6,
+	.targetsize	= sizeof(struct nf_nat_range),
+	.table		= "nat",
+	.hooks		= 1 << NF_INET_POST_ROUTING,
+	.me		= THIS_MODULE,
+};
+
+static int __init masquerade_tg6_init(void)
+{
+	int err;
+
+	err = xt_register_target(&masquerade_tg6_reg);
+	if (err == 0) {
+		register_netdevice_notifier(&masq_dev_notifier);
+		register_inet6addr_notifier(&masq_inet_notifier);
+	}
+
+	return err;
+}
+static void __exit masquerade_tg6_exit(void)
+{
+	unregister_inet6addr_notifier(&masq_inet_notifier);
+	unregister_netdevice_notifier(&masq_dev_notifier);
+	xt_unregister_target(&masquerade_tg6_reg);
+}
+
+module_init(masquerade_tg6_init);
+module_exit(masquerade_tg6_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_DESCRIPTION("Xtables: automatic address SNAT");
...	...	@@ -78,7 +78,7 @@
78	78	int strict);
79	79
80	80	extern int ipv6_dev_get_saddr(struct net *net,
81		- struct net_device *dev,
	81	+ const struct net_device *dev,
82	82	const struct in6_addr *daddr,
83	83	unsigned int srcprefs,
84	84	struct in6_addr *saddr);
...	...	@@ -43,7 +43,9 @@
43	43	struct nf_conn *ct;
44	44	union nf_conntrack_nat_help help;
45	45	#if defined(CONFIG_IP_NF_TARGET_MASQUERADE) \|\| \
46		- defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE)
	46	+ defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE) \|\| \
	47	+ defined(CONFIG_IP6_NF_TARGET_MASQUERADE) \|\| \
	48	+ defined(CONFIG_IP6_NF_TARGET_MASQUERADE_MODULE)
47	49	int masq_index;
48	50	#endif
49	51	};
...	...	@@ -99,7 +99,8 @@
99	99
100	100	if (!nat)
101	101	return 0;
102		-
	102	+ if (nf_ct_l3num(i) != NFPROTO_IPV4)
	103	+ return 0;
103	104	return nat->masq_index == (int)(long)ifindex;
104	105	}
105	106
...	...	@@ -1093,7 +1093,7 @@
1093	1093	return ret;
1094	1094	}
1095	1095
1096		-int ipv6_dev_get_saddr(struct net net, struct net_device dst_dev,
	1096	+int ipv6_dev_get_saddr(struct net net, const struct net_device dst_dev,
1097	1097	const struct in6_addr *daddr, unsigned int prefs,
1098	1098	struct in6_addr *saddr)
1099	1099	{
...	...	@@ -144,6 +144,18 @@
144	144	(e.g. when running oldconfig). It selects
145	145	CONFIG_NETFILTER_XT_TARGET_HL.
146	146
	147	+config IP6_NF_TARGET_MASQUERADE
	148	+ tristate "MASQUERADE target support"
	149	+ depends on NF_NAT_IPV6
	150	+ help
	151	+ Masquerading is a special case of NAT: all outgoing connections are
	152	+ changed to seem to come from a particular interface's address, and
	153	+ if the interface goes down, those connections are lost. This is
	154	+ only useful for dialup accounts with dynamic IP address (ie. your IP
	155	+ address will be different on next dialup).
	156	+
	157	+ To compile it as a module, choose M here. If unsure, say N.
	158	+
147	159	config IP6_NF_FILTER
148	160	tristate "Packet filtering"
149	161	default m if NETFILTER_ADVANCED=n
...	...	@@ -34,5 +34,6 @@
34	34	obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o
35	35
36	36	# targets
	37	+obj-$(CONFIG_IP6_NF_TARGET_MASQUERADE) += ip6t_MASQUERADE.o
37	38	obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o
	1	+/*
	2	+ * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
	3	+ *
	4	+ * This program is free software; you can redistribute it and/or modify
	5	+ * it under the terms of the GNU General Public License version 2 as
	6	+ * published by the Free Software Foundation.
	7	+ *
	8	+ * Based on Rusty Russell's IPv6 MASQUERADE target. Development of IPv6
	9	+ * NAT funded by Astaro.
	10	+ */
	11	+
	12	+#include <linux/kernel.h>
	13	+#include <linux/module.h>
	14	+#include <linux/netdevice.h>
	15	+#include <linux/ipv6.h>
	16	+#include <linux/netfilter.h>
	17	+#include <linux/netfilter_ipv6.h>
	18	+#include <linux/netfilter/x_tables.h>
	19	+#include <net/netfilter/nf_nat.h>
	20	+#include <net/addrconf.h>
	21	+#include <net/ipv6.h>
	22	+
	23	+static unsigned int
	24	+masquerade_tg6(struct sk_buff skb, const struct xt_action_param par)
	25	+{
	26	+ const struct nf_nat_range *range = par->targinfo;
	27	+ enum ip_conntrack_info ctinfo;
	28	+ struct in6_addr src;
	29	+ struct nf_conn *ct;
	30	+ struct nf_nat_range newrange;
	31	+
	32	+ ct = nf_ct_get(skb, &ctinfo);
	33	+ NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW \|\| ctinfo == IP_CT_RELATED \|\|
	34	+ ctinfo == IP_CT_RELATED_REPLY));
	35	+
	36	+ if (ipv6_dev_get_saddr(dev_net(par->out), par->out,
	37	+ &ipv6_hdr(skb)->daddr, 0, &src) < 0)
	38	+ return NF_DROP;
	39	+
	40	+ nfct_nat(ct)->masq_index = par->out->ifindex;
	41	+
	42	+ newrange.flags = range->flags \| NF_NAT_RANGE_MAP_IPS;
	43	+ newrange.min_addr.in6 = src;
	44	+ newrange.max_addr.in6 = src;
	45	+ newrange.min_proto = range->min_proto;
	46	+ newrange.max_proto = range->max_proto;
	47	+
	48	+ return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
	49	+}
	50	+
	51	+static int masquerade_tg6_checkentry(const struct xt_tgchk_param *par)
	52	+{
	53	+ const struct nf_nat_range *range = par->targinfo;
	54	+
	55	+ if (range->flags & NF_NAT_RANGE_MAP_IPS)
	56	+ return -EINVAL;
	57	+ return 0;
	58	+}
	59	+
	60	+static int device_cmp(struct nf_conn ct, void ifindex)
	61	+{
	62	+ const struct nf_conn_nat *nat = nfct_nat(ct);
	63	+
	64	+ if (!nat)
	65	+ return 0;
	66	+ if (nf_ct_l3num(ct) != NFPROTO_IPV6)
	67	+ return 0;
	68	+ return nat->masq_index == (int)(long)ifindex;
	69	+}
	70	+
	71	+static int masq_device_event(struct notifier_block *this,
	72	+ unsigned long event, void *ptr)
	73	+{
	74	+ const struct net_device *dev = ptr;
	75	+ struct net *net = dev_net(dev);
	76	+
	77	+ if (event == NETDEV_DOWN)
	78	+ nf_ct_iterate_cleanup(net, device_cmp,
	79	+ (void *)(long)dev->ifindex);
	80	+
	81	+ return NOTIFY_DONE;
	82	+}
	83	+
	84	+static struct notifier_block masq_dev_notifier = {
	85	+ .notifier_call = masq_device_event,
	86	+};
	87	+
	88	+static int masq_inet_event(struct notifier_block *this,
	89	+ unsigned long event, void *ptr)
	90	+{
	91	+ struct inet6_ifaddr *ifa = ptr;
	92	+
	93	+ return masq_device_event(this, event, ifa->idev->dev);
	94	+}
	95	+
	96	+static struct notifier_block masq_inet_notifier = {
	97	+ .notifier_call = masq_inet_event,
	98	+};
	99	+
	100	+static struct xt_target masquerade_tg6_reg __read_mostly = {
	101	+ .name = "MASQUERADE",
	102	+ .family = NFPROTO_IPV6,
	103	+ .checkentry = masquerade_tg6_checkentry,
	104	+ .target = masquerade_tg6,
	105	+ .targetsize = sizeof(struct nf_nat_range),
	106	+ .table = "nat",
	107	+ .hooks = 1 << NF_INET_POST_ROUTING,
	108	+ .me = THIS_MODULE,
	109	+};
	110	+
	111	+static int __init masquerade_tg6_init(void)
	112	+{
	113	+ int err;
	114	+
	115	+ err = xt_register_target(&masquerade_tg6_reg);
	116	+ if (err == 0) {
	117	+ register_netdevice_notifier(&masq_dev_notifier);
	118	+ register_inet6addr_notifier(&masq_inet_notifier);
	119	+ }
	120	+
	121	+ return err;
	122	+}
	123	+static void __exit masquerade_tg6_exit(void)
	124	+{
	125	+ unregister_inet6addr_notifier(&masq_inet_notifier);
	126	+ unregister_netdevice_notifier(&masq_dev_notifier);
	127	+ xt_unregister_target(&masquerade_tg6_reg);
	128	+}
	129	+
	130	+module_init(masquerade_tg6_init);
	131	+module_exit(masquerade_tg6_exit);
	132	+
	133	+MODULE_LICENSE("GPL");
	134	+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
	135	+MODULE_DESCRIPTION("Xtables: automatic address SNAT");