=?y?q?=5BPATCH=20nf-next=203/4=5D=20netfilter=3A=20move=20generic=20TEE=20code=20from=20xtables=20to=20nf=5Ftee=5Fipv=7B4=2C6=7D=20modules?=

[Pablo Neira Ayuso <pablo@netfilter.org>]

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This allows us to reuse the existing code from nf_tables. Based on original
work from Arturo Borrero Gonzalez.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/ipv4/nf_tee_ipv4.h |    9 ++
 include/net/netfilter/ipv6/nf_tee_ipv6.h |    9 ++
 include/net/netfilter/nf_tee.h           |   23 +++
 include/uapi/linux/netfilter/xt_TEE.h    |    2 +-
 net/ipv4/netfilter/Kconfig               |    7 +
 net/ipv4/netfilter/Makefile              |    2 +
 net/ipv4/netfilter/nf_tee_ipv4.c         |  115 +++++++++++++++
 net/ipv6/netfilter/Kconfig               |    7 +
 net/ipv6/netfilter/Makefile              |    2 +
 net/ipv6/netfilter/nf_tee_ipv6.c         |   89 +++++++++++
 net/netfilter/Kconfig                    |   10 ++
 net/netfilter/Makefile                   |    2 +
 net/netfilter/nf_tee.c                   |   98 +++++++++++++
 net/netfilter/xt_TEE.c                   |  236 ++----------------------------
 14 files changed, 388 insertions(+), 223 deletions(-)
 create mode 100644 include/net/netfilter/ipv4/nf_tee_ipv4.h
 create mode 100644 include/net/netfilter/ipv6/nf_tee_ipv6.h
 create mode 100644 include/net/netfilter/nf_tee.h
 create mode 100644 net/ipv4/netfilter/nf_tee_ipv4.c
 create mode 100644 net/ipv6/netfilter/nf_tee_ipv6.c
 create mode 100644 net/netfilter/nf_tee.c

diff --git a/include/net/netfilter/ipv4/nf_tee_ipv4.h b/include/net/netfilter/ipv4/nf_tee_ipv4.h
new file mode 100644
index 0000000..434e561
--- /dev/null
+++ b/include/net/netfilter/ipv4/nf_tee_ipv4.h
@@ -0,0 +1,9 @@
+#ifndef _NF_TEE_IPV4_H_
+#define _NF_TEE_IPV4_H_
+
+#include <net/netfilter/nf_tee.h>
+
+unsigned int nf_tee_ipv4(struct sk_buff *skb, const struct nf_tee *tee,
+			 unsigned int hooknum);
+
+#endif /* _NF_TEE_IPV4_H_ */
diff --git a/include/net/netfilter/ipv6/nf_tee_ipv6.h b/include/net/netfilter/ipv6/nf_tee_ipv6.h
new file mode 100644
index 0000000..842cbcf
--- /dev/null
+++ b/include/net/netfilter/ipv6/nf_tee_ipv6.h
@@ -0,0 +1,9 @@
+#ifndef _NF_TEE_IPV6_H_
+#define _NF_TEE_IPV6_H_
+
+#include <net/netfilter/nf_tee.h>
+
+unsigned int nf_tee_ipv6(struct sk_buff *skb, const struct nf_tee *tee,
+			 unsigned int hooknum);
+
+#endif /* _NF_TEE_IPV6_H_ */
diff --git a/include/net/netfilter/nf_tee.h b/include/net/netfilter/nf_tee.h
new file mode 100644
index 0000000..7a93cb1
--- /dev/null
+++ b/include/net/netfilter/nf_tee.h
@@ -0,0 +1,23 @@
+#ifndef _NF_TEE_H_
+#define _NF_TEE_H_
+
+#include <linux/netfilter.h>
+#include <linux/if.h>
+
+struct nf_tee {
+	union nf_inet_addr	gw;
+	char			oifname[IFNAMSIZ];
+	int			oif;
+	struct notifier_block	notifier;
+};
+
+struct net *nf_tee_pick_net(struct sk_buff *skb);
+int nf_tee_init(struct nf_tee *tee, union nf_inet_addr gw, const char *oifname);
+void nf_tee_fini(struct nf_tee *tee);
+
+static inline bool nf_tee_has_notifier(const struct nf_tee *tee)
+{
+	return tee->notifier.notifier_call != NULL;
+}
+
+#endif
diff --git a/include/uapi/linux/netfilter/xt_TEE.h b/include/uapi/linux/netfilter/xt_TEE.h
index 5c21d5c..754e43f 100644
--- a/include/uapi/linux/netfilter/xt_TEE.h
+++ b/include/uapi/linux/netfilter/xt_TEE.h
@@ -6,7 +6,7 @@ struct xt_tee_tginfo {
 	char oif[16];
 
 	/* used internally by the kernel */
-	struct xt_tee_priv *priv __attribute__((aligned(8)));
+	struct nf_tee *priv __attribute__((aligned(8)));
 };
 
 #endif /* _XT_TEE_TARGET_H */
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 2199a5d..2153bb2 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -67,6 +67,13 @@ config NF_TABLES_ARP
 
 endif # NF_TABLES
 
+config NF_TEE_IPV4
+	tristate "Netfilter IPv4 packet cloning to alternate destination"
+	select NF_TEE
+	help
+	  This option enables the nf_tee_ipv4 core, which clones an IPv4 packet
+	  to be rerouted to another destination.
+
 config NF_LOG_ARP
 	tristate "ARP packet logging"
 	default m if NETFILTER_ADVANCED=n
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 7fe6c70..6b492de 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -70,3 +70,5 @@ obj-$(CONFIG_IP_NF_ARP_MANGLE) += arpt_mangle.o
 
 # just filtering instance of ARP tables for now
 obj-$(CONFIG_IP_NF_ARPFILTER) += arptable_filter.o
+
+obj-$(CONFIG_NF_TEE_IPV4) += nf_tee_ipv4.o
diff --git a/net/ipv4/netfilter/nf_tee_ipv4.c b/net/ipv4/netfilter/nf_tee_ipv4.c
new file mode 100644
index 0000000..2dcc1a8
--- /dev/null
+++ b/net/ipv4/netfilter/nf_tee_ipv4.c
@@ -0,0 +1,115 @@
+/*
+ * (C) 2007 by Sebastian Claßen
+ * (C) 2007-2010 by Jan Engelhardt
+ *
+ * Extracted from xt_TEE.c
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later, as
+ * published by the Free Software Foundation.
+ */
+#include <linux/ip.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/route.h>
+#include <linux/skbuff.h>
+#include <net/checksum.h>
+#include <net/icmp.h>
+#include <net/ip.h>
+#include <net/route.h>
+#include <net/netfilter/nf_tee.h>
+#include <net/netfilter/ipv4/nf_tee_ipv4.h>
+
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+#	define WITH_CONNTRACK 1
+#	include <net/netfilter/nf_conntrack.h>
+#endif
+
+static DEFINE_PER_CPU(bool, tee_active);
+
+static bool nf_tee_ipv4_route(struct sk_buff *skb, const struct nf_tee *tee)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	struct net *net = nf_tee_pick_net(skb);
+	struct rtable *rt;
+	struct flowi4 fl4;
+
+	memset(&fl4, 0, sizeof(fl4));
+	if (nf_tee_has_notifier(tee)) {
+		if (tee->oif == -1)
+			return false;
+
+		fl4.flowi4_oif = tee->oif;
+	}
+	fl4.daddr = tee->gw.ip;
+	fl4.flowi4_tos = RT_TOS(iph->tos);
+	fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
+	fl4.flowi4_flags = FLOWI_FLAG_KNOWN_NH;
+	rt = ip_route_output_key(net, &fl4);
+	if (IS_ERR(rt))
+		return false;
+
+	skb_dst_drop(skb);
+	skb_dst_set(skb, &rt->dst);
+	skb->dev      = rt->dst.dev;
+	skb->protocol = htons(ETH_P_IP);
+
+	return true;
+}
+
+unsigned int nf_tee_ipv4(struct sk_buff *skb, const struct nf_tee *tee,
+			 unsigned int hooknum)
+{
+	struct iphdr *iph;
+
+	if (__this_cpu_read(tee_active))
+		return XT_CONTINUE;
+	/*
+	 * Copy the skb, and route the copy. Will later return %XT_CONTINUE for
+	 * the original skb, which should continue on its way as if nothing has
+	 * happened. The copy should be independently delivered to the TEE
+	 * --gateway.
+	 */
+	skb = pskb_copy(skb, GFP_ATOMIC);
+	if (skb == NULL)
+		return XT_CONTINUE;
+
+#ifdef WITH_CONNTRACK
+	/* Avoid counting cloned packets towards the original connection. */
+	nf_conntrack_put(skb->nfct);
+	skb->nfct     = &nf_ct_untracked_get()->ct_general;
+	skb->nfctinfo = IP_CT_NEW;
+	nf_conntrack_get(skb->nfct);
+#endif
+	/*
+	 * If we are in PREROUTING/INPUT, the checksum must be recalculated
+	 * since the length could have changed as a result of defragmentation.
+	 *
+	 * We also decrease the TTL to mitigate potential TEE loops
+	 * between two hosts.
+	 *
+	 * Set %IP_DF so that the original source is notified of a potentially
+	 * decreased MTU on the clone route. IPv6 does this too.
+	 */
+	iph = ip_hdr(skb);
+	iph->frag_off |= htons(IP_DF);
+	if (hooknum == NF_INET_PRE_ROUTING ||
+	    hooknum == NF_INET_LOCAL_IN)
+		--iph->ttl;
+	ip_send_check(iph);
+
+	if (nf_tee_ipv4_route(skb, tee)) {
+		__this_cpu_write(tee_active, true);
+		ip_local_out(skb);
+		__this_cpu_write(tee_active, false);
+	} else {
+		kfree_skb(skb);
+	}
+	return XT_CONTINUE;
+}
+EXPORT_SYMBOL_GPL(nf_tee_ipv4);
+
+MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
+MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
+MODULE_DESCRIPTION("nf_tee_ipv4: Reroute IPv4 packet copy");
+MODULE_LICENSE("GPL");
diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index b552cf0..92c37bb 100644
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -59,6 +59,13 @@ config NF_LOG_IPV6
 	default m if NETFILTER_ADVANCED=n
 	select NF_LOG_COMMON
 
+config NF_TEE_IPV6
+	tristate "Netfilter IPv6 packet cloning to alternate destination"
+	select NF_TEE
+	help
+	  This option enables the nf_tee_ipv6 core, which clone an IPv6 packet
+	  to be rerouted to another destination.
+
 config NF_NAT_IPV6
 	tristate "IPv6 NAT"
 	depends on NF_CONNTRACK_IPV6
diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index c36e0a5..b3a2946 100644
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -30,6 +30,8 @@ obj-$(CONFIG_NF_LOG_IPV6) += nf_log_ipv6.o
 # reject
 obj-$(CONFIG_NF_REJECT_IPV6) += nf_reject_ipv6.o
 
+obj-$(CONFIG_NF_TEE_IPV6) += nf_tee_ipv6.o
+
 # nf_tables
 obj-$(CONFIG_NF_TABLES_IPV6) += nf_tables_ipv6.o
 obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV6) += nft_chain_route_ipv6.o
diff --git a/net/ipv6/netfilter/nf_tee_ipv6.c b/net/ipv6/netfilter/nf_tee_ipv6.c
new file mode 100644
index 0000000..f13b61f9
--- /dev/null
+++ b/net/ipv6/netfilter/nf_tee_ipv6.c
@@ -0,0 +1,89 @@
+/*
+ * (C) 2007 by Sebastian Claßen
+ * (C) 2007-2010 by Jan Engelhardt
+ *
+ * Extracted from xt_TEE.c
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later, as
+ * published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/skbuff.h>
+#include <net/ipv6.h>
+#include <net/ip6_route.h>
+#include <net/netfilter/nf_tee.h>
+#include <net/netfilter/ipv6/nf_tee_ipv6.h>
+
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+#	define WITH_CONNTRACK 1
+#	include <net/netfilter/nf_conntrack.h>
+#endif
+
+static DEFINE_PER_CPU(bool, tee_active);
+
+static bool nf_tee_ipv6_route(struct sk_buff *skb, const struct nf_tee *tee)
+{
+	const struct ipv6hdr *iph = ipv6_hdr(skb);
+	struct net *net = nf_tee_pick_net(skb);
+	struct dst_entry *dst;
+	struct flowi6 fl6;
+
+	memset(&fl6, 0, sizeof(fl6));
+	if (nf_tee_has_notifier(tee)) {
+		if (tee->oif == -1)
+			return false;
+		fl6.flowi6_oif = tee->oif;
+	}
+	fl6.daddr = tee->gw.in6;
+	fl6.flowlabel = ((iph->flow_lbl[0] & 0xF) << 16) |
+			 (iph->flow_lbl[1] << 8) | iph->flow_lbl[2];
+	dst = ip6_route_output(net, NULL, &fl6);
+	if (dst->error) {
+		dst_release(dst);
+		return false;
+	}
+	skb_dst_drop(skb);
+	skb_dst_set(skb, dst);
+	skb->dev      = dst->dev;
+	skb->protocol = htons(ETH_P_IPV6);
+
+	return true;
+}
+
+unsigned int nf_tee_ipv6(struct sk_buff *skb, const struct nf_tee *tee,
+			 unsigned int hooknum)
+{
+	if (__this_cpu_read(tee_active))
+		return XT_CONTINUE;
+	skb = pskb_copy(skb, GFP_ATOMIC);
+	if (skb == NULL)
+		return XT_CONTINUE;
+
+#ifdef WITH_CONNTRACK
+	nf_conntrack_put(skb->nfct);
+	skb->nfct     = &nf_ct_untracked_get()->ct_general;
+	skb->nfctinfo = IP_CT_NEW;
+	nf_conntrack_get(skb->nfct);
+#endif
+	if (hooknum == NF_INET_PRE_ROUTING ||
+	    hooknum == NF_INET_LOCAL_IN) {
+		struct ipv6hdr *iph = ipv6_hdr(skb);
+		--iph->hop_limit;
+	}
+	if (nf_tee_ipv6_route(skb, tee)) {
+		__this_cpu_write(tee_active, true);
+		ip6_local_out(skb);
+		__this_cpu_write(tee_active, false);
+	} else {
+		kfree_skb(skb);
+	}
+	return XT_CONTINUE;
+}
+EXPORT_SYMBOL_GPL(nf_tee_ipv6);
+
+MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
+MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
+MODULE_DESCRIPTION("nf_tee_ipv6: Reroute IPv6 packet copy");
+MODULE_LICENSE("GPL");
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 6eae69a..afdba34 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -564,6 +564,14 @@ config NFT_COMPAT
 
 endif # NF_TABLES
 
+config NF_TEE
+	tristate "Netfilter nf_tee module"
+	depends on !NF_CONNTRACK || NF_CONNTRACK
+	help
+	  This module is the core nf_tee engine, which allows you
+	  to copy and redirect packets to another gateway.
+
+
 config NETFILTER_XTABLES
 	tristate "Netfilter Xtables support (required for ip_tables)"
 	default m if NETFILTER_ADVANCED=n
@@ -867,6 +875,8 @@ config NETFILTER_XT_TARGET_TEE
 	depends on NETFILTER_ADVANCED
 	depends on IPV6 || IPV6=n
 	depends on !NF_CONNTRACK || NF_CONNTRACK
+	select NF_TEE_IPV4
+	select NF_TEE_IPV6 if IP6_NF_IPTABLES
 	---help---
 	This option adds a "TEE" target with which a packet can be cloned and
 	this clone be rerouted to another nexthop.
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 70d026d..9be0e4b 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -47,6 +47,8 @@ obj-$(CONFIG_NF_CONNTRACK_TFTP) += nf_conntrack_tftp.o
 nf_nat-y	:= nf_nat_core.o nf_nat_proto_unknown.o nf_nat_proto_common.o \
 		   nf_nat_proto_udp.o nf_nat_proto_tcp.o nf_nat_helper.o
 
+obj-$(CONFIG_NF_TEE) += nf_tee.o
+
 # generic transport layer logging
 obj-$(CONFIG_NF_LOG_COMMON) += nf_log_common.o
 
diff --git a/net/netfilter/nf_tee.c b/net/netfilter/nf_tee.c
new file mode 100644
index 0000000..a53f351
--- /dev/null
+++ b/net/netfilter/nf_tee.c
@@ -0,0 +1,98 @@
+/*
+ * (C) 2007 by Sebastian Claßen <sebastian.classen@freenet.ag>
+ * (C) 2007-2010 by Jan Engelhardt <jengelh@medozas.de>
+ *
+ * Extracted from xt_TEE.c
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later, as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/ip.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/skbuff.h>
+#include <linux/notifier.h>
+#include <linux/netdevice.h>
+#include <net/net_namespace.h>
+#include <net/dst.h>
+#include <net/netfilter/nf_tee.h>
+
+struct net *nf_tee_pick_net(struct sk_buff *skb)
+{
+#ifdef CONFIG_NET_NS
+	const struct dst_entry *dst;
+
+	if (skb->dev != NULL)
+		return dev_net(skb->dev);
+	dst = skb_dst(skb);
+	if (dst != NULL && dst->dev != NULL)
+		return dev_net(dst->dev);
+#endif
+	return &init_net;
+}
+EXPORT_SYMBOL_GPL(nf_tee_pick_net);
+
+static int nf_tee_netdev_event(struct notifier_block *this, unsigned long event,
+			       void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct nf_tee *tee;
+
+	tee = container_of(this, struct nf_tee, notifier);
+	switch (event) {
+	case NETDEV_REGISTER:
+		if (!strcmp(dev->name, tee->oifname))
+			tee->oif = dev->ifindex;
+		break;
+	case NETDEV_UNREGISTER:
+		if (dev->ifindex == tee->oif)
+			tee->oif = -1;
+		break;
+	case NETDEV_CHANGENAME:
+		if (!strcmp(dev->name, tee->oifname))
+			tee->oif = dev->ifindex;
+		else if (dev->ifindex == tee->oif)
+			tee->oif = -1;
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static const union nf_inet_addr tee_zero_address;
+
+int nf_tee_init(struct nf_tee *tee, union nf_inet_addr gw, const char *oifname)
+{
+	/* 0.0.0.0 and :: not allowed */
+	if (memcmp(&gw, &tee_zero_address, sizeof(tee_zero_address)) == 0)
+		return -EOPNOTSUPP;
+
+	memcpy(&tee->gw, &gw, sizeof(gw));
+	tee->oif = -1;
+
+	if (oifname[0]) {
+		if (oifname[sizeof(tee->oifname) - 1] != '\0')
+			return -EINVAL;
+
+		memcpy(tee->oifname, oifname, sizeof(tee->oifname));
+		tee->notifier.notifier_call = nf_tee_netdev_event;
+		register_netdevice_notifier(&tee->notifier);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nf_tee_init);
+
+void nf_tee_fini(struct nf_tee *tee)
+{
+	if (nf_tee_has_notifier(tee))
+		unregister_netdevice_notifier(&tee->notifier);
+}
+EXPORT_SYMBOL_GPL(nf_tee_fini);
+
+MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
+MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
+MODULE_DESCRIPTION("nf_tee: Reroute packet copy");
+MODULE_LICENSE("GPL");
diff --git a/net/netfilter/xt_TEE.c b/net/netfilter/xt_TEE.c
index 189ad13..6bd9a4d 100644
--- a/net/netfilter/xt_TEE.c
+++ b/net/netfilter/xt_TEE.c
@@ -10,256 +10,50 @@
  *	modify it under the terms of the GNU General Public License
  *	version 2 or later, as published by the Free Software Foundation.
  */
-#include <linux/ip.h>
 #include <linux/module.h>
-#include <linux/percpu.h>
-#include <linux/route.h>
 #include <linux/skbuff.h>
-#include <linux/notifier.h>
-#include <net/checksum.h>
-#include <net/icmp.h>
-#include <net/ip.h>
-#include <net/ipv6.h>
-#include <net/ip6_route.h>
-#include <net/route.h>
 #include <linux/netfilter/x_tables.h>
+#include <net/netfilter/ipv4/nf_tee_ipv4.h>
+#include <net/netfilter/ipv6/nf_tee_ipv6.h>
 #include <linux/netfilter/xt_TEE.h>
 
-#if IS_ENABLED(CONFIG_NF_CONNTRACK)
-#	define WITH_CONNTRACK 1
-#	include <net/netfilter/nf_conntrack.h>
-#endif
-
-struct xt_tee_priv {
-	struct notifier_block	notifier;
-	struct xt_tee_tginfo	*tginfo;
-	int			oif;
-};
-
-static const union nf_inet_addr tee_zero_address;
-static DEFINE_PER_CPU(bool, tee_active);
-
-static struct net *pick_net(struct sk_buff *skb)
-{
-#ifdef CONFIG_NET_NS
-	const struct dst_entry *dst;
-
-	if (skb->dev != NULL)
-		return dev_net(skb->dev);
-	dst = skb_dst(skb);
-	if (dst != NULL && dst->dev != NULL)
-		return dev_net(dst->dev);
-#endif
-	return &init_net;
-}
-
-static inline bool tee_has_notifier(const struct xt_tee_tginfo *info)
-{
-	return info->priv->notifier.notifier_call != NULL;
-}
-
-static bool
-tee_tg_route4(struct sk_buff *skb, const struct xt_tee_tginfo *info)
-{
-	const struct iphdr *iph = ip_hdr(skb);
-	struct net *net = pick_net(skb);
-	struct rtable *rt;
-	struct flowi4 fl4;
-
-	memset(&fl4, 0, sizeof(fl4));
-	if (tee_has_notifier(info)) {
-		if (info->priv->oif == -1)
-			return false;
-		fl4.flowi4_oif = info->priv->oif;
-	}
-	fl4.daddr = info->gw.ip;
-	fl4.flowi4_tos = RT_TOS(iph->tos);
-	fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
-	fl4.flowi4_flags = FLOWI_FLAG_KNOWN_NH;
-	rt = ip_route_output_key(net, &fl4);
-	if (IS_ERR(rt))
-		return false;
-
-	skb_dst_drop(skb);
-	skb_dst_set(skb, &rt->dst);
-	skb->dev      = rt->dst.dev;
-	skb->protocol = htons(ETH_P_IP);
-	return true;
-}
-
 static unsigned int
 tee_tg4(struct sk_buff *skb, const struct xt_action_param *par)
 {
 	const struct xt_tee_tginfo *info = par->targinfo;
-	struct iphdr *iph;
 
-	if (__this_cpu_read(tee_active))
-		return XT_CONTINUE;
-	/*
-	 * Copy the skb, and route the copy. Will later return %XT_CONTINUE for
-	 * the original skb, which should continue on its way as if nothing has
-	 * happened. The copy should be independently delivered to the TEE
-	 * --gateway.
-	 */
-	skb = pskb_copy(skb, GFP_ATOMIC);
-	if (skb == NULL)
-		return XT_CONTINUE;
-
-#ifdef WITH_CONNTRACK
-	/* Avoid counting cloned packets towards the original connection. */
-	nf_conntrack_put(skb->nfct);
-	skb->nfct     = &nf_ct_untracked_get()->ct_general;
-	skb->nfctinfo = IP_CT_NEW;
-	nf_conntrack_get(skb->nfct);
-#endif
-	/*
-	 * If we are in PREROUTING/INPUT, the checksum must be recalculated
-	 * since the length could have changed as a result of defragmentation.
-	 *
-	 * We also decrease the TTL to mitigate potential TEE loops
-	 * between two hosts.
-	 *
-	 * Set %IP_DF so that the original source is notified of a potentially
-	 * decreased MTU on the clone route. IPv6 does this too.
-	 */
-	iph = ip_hdr(skb);
-	iph->frag_off |= htons(IP_DF);
-	if (par->hooknum == NF_INET_PRE_ROUTING ||
-	    par->hooknum == NF_INET_LOCAL_IN)
-		--iph->ttl;
-	ip_send_check(iph);
-
-	if (tee_tg_route4(skb, info)) {
-		__this_cpu_write(tee_active, true);
-		ip_local_out(skb);
-		__this_cpu_write(tee_active, false);
-	} else {
-		kfree_skb(skb);
-	}
-	return XT_CONTINUE;
+	return nf_tee_ipv4(skb, info->priv, par->hooknum);
 }
 
 #if IS_ENABLED(CONFIG_IPV6)
-static bool
-tee_tg_route6(struct sk_buff *skb, const struct xt_tee_tginfo *info)
-{
-	const struct ipv6hdr *iph = ipv6_hdr(skb);
-	struct net *net = pick_net(skb);
-	struct dst_entry *dst;
-	struct flowi6 fl6;
-
-	memset(&fl6, 0, sizeof(fl6));
-	if (tee_has_notifier(info)) {
-		if (info->priv->oif == -1)
-			return false;
-		fl6.flowi6_oif = info->priv->oif;
-	}
-	fl6.daddr = info->gw.in6;
-	fl6.flowlabel = ((iph->flow_lbl[0] & 0xF) << 16) |
-			   (iph->flow_lbl[1] << 8) | iph->flow_lbl[2];
-	fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
-	dst = ip6_route_output(net, NULL, &fl6);
-	if (dst->error) {
-		dst_release(dst);
-		return false;
-	}
-	skb_dst_drop(skb);
-	skb_dst_set(skb, dst);
-	skb->dev      = dst->dev;
-	skb->protocol = htons(ETH_P_IPV6);
-	return true;
-}
-
 static unsigned int
 tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
 {
 	const struct xt_tee_tginfo *info = par->targinfo;
 
-	if (__this_cpu_read(tee_active))
-		return XT_CONTINUE;
-	skb = pskb_copy(skb, GFP_ATOMIC);
-	if (skb == NULL)
-		return XT_CONTINUE;
-
-#ifdef WITH_CONNTRACK
-	nf_conntrack_put(skb->nfct);
-	skb->nfct     = &nf_ct_untracked_get()->ct_general;
-	skb->nfctinfo = IP_CT_NEW;
-	nf_conntrack_get(skb->nfct);
-#endif
-	if (par->hooknum == NF_INET_PRE_ROUTING ||
-	    par->hooknum == NF_INET_LOCAL_IN) {
-		struct ipv6hdr *iph = ipv6_hdr(skb);
-		--iph->hop_limit;
-	}
-	if (tee_tg_route6(skb, info)) {
-		__this_cpu_write(tee_active, true);
-		ip6_local_out(skb);
-		__this_cpu_write(tee_active, false);
-	} else {
-		kfree_skb(skb);
-	}
-	return XT_CONTINUE;
+	return nf_tee_ipv6(skb, info->priv, par->hooknum);
 }
 #endif
 
-static int tee_netdev_event(struct notifier_block *this, unsigned long event,
-			    void *ptr)
-{
-	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-	struct xt_tee_priv *priv;
-
-	priv = container_of(this, struct xt_tee_priv, notifier);
-	switch (event) {
-	case NETDEV_REGISTER:
-		if (!strcmp(dev->name, priv->tginfo->oif))
-			priv->oif = dev->ifindex;
-		break;
-	case NETDEV_UNREGISTER:
-		if (dev->ifindex == priv->oif)
-			priv->oif = -1;
-		break;
-	case NETDEV_CHANGENAME:
-		if (!strcmp(dev->name, priv->tginfo->oif))
-			priv->oif = dev->ifindex;
-		else if (dev->ifindex == priv->oif)
-			priv->oif = -1;
-		break;
-	}
-
-	return NOTIFY_DONE;
-}
-
 static int tee_tg_check(const struct xt_tgchk_param *par)
 {
 	struct xt_tee_tginfo *info = par->targinfo;
-	struct xt_tee_priv *priv;
+	struct nf_tee *tee;
+	int ret;
 
-	/* 0.0.0.0 and :: not allowed */
-	if (memcmp(&info->gw, &tee_zero_address,
-		   sizeof(tee_zero_address)) == 0)
-		return -EINVAL;
-
-	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
-	if (priv == NULL)
+	tee = kzalloc(sizeof(*tee), GFP_KERNEL);
+	if (tee == NULL)
 		return -ENOMEM;
 
-	priv->tginfo	= info;
-	priv->oif	= -1;
-
-	if (info->oif[0]) {
-		if (info->oif[sizeof(info->oif)-1] != '\0')
-			goto err1;
+	ret = nf_tee_init(tee, info->gw, info->oif);
+	if (ret < 0)
+		goto err1;
 
-		priv->notifier.notifier_call = tee_netdev_event;
-		register_netdevice_notifier(&priv->notifier);
-	}
-
-	info->priv	= priv;
+	info->priv = tee;
 
 	return 0;
 err1:
-	kfree(priv);
+	kfree(tee);
 	return -EINVAL;
 }
 
@@ -267,9 +61,7 @@ static void tee_tg_destroy(const struct xt_tgdtor_param *par)
 {
 	struct xt_tee_tginfo *info = par->targinfo;
 
-	if (tee_has_notifier(info))
-		unregister_netdevice_notifier(&info->priv->notifier);
-
+	nf_tee_fini(info->priv);
 	kfree(info->priv);
 }
 
-- 
1.7.10.4

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