qca-nss-ecm/frontends/ecm_front_end_ipv4.c - manifest_repos/sdk - Git at Google

 /*
  **************************************************************************
  * Copyright (c) 2015-2016, 2020-2021 The Linux Foundation. All rights reserved.
  * Permission to use, copy, modify, and/or distribute this software for
  * any purpose with or without fee is hereby granted, provided that the
  * above copyright notice and this permission notice appear in all copies.
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  **************************************************************************
  */

 #include <linux/version.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/debugfs.h>
 #include <linux/inet.h>
 #include <linux/etherdevice.h>
 #include <net/netfilter/nf_conntrack.h>
 #include <net/ip.h>
 #include <net/ipv6.h>
 #include <net/route.h>

 /*
  * Debug output levels
  * 0 = OFF
  * 1 = ASSERTS / ERRORS
  * 2 = 1 + WARN
  * 3 = 2 + INFO
  * 4 = 3 + TRACE
  */
 #define DEBUG_LEVEL ECM_FRONT_END_IPV4_DEBUG_LEVEL

 #include "ecm_types.h"
 #include "ecm_db_types.h"
 #include "ecm_state.h"
 #include "ecm_tracker.h"
 #include "ecm_classifier.h"
 #include "ecm_front_end_types.h"
 #include "ecm_tracker_datagram.h"
 #include "ecm_tracker_udp.h"
 #include "ecm_tracker_tcp.h"
 #include "ecm_db.h"
 #include "ecm_front_end_ipv4.h"
 #include "ecm_interface.h"
 #include "ecm_ipv4.h"

 /*
  * General operational control
  */
 int ecm_front_end_ipv4_stopped = 0;	/* When non-zero further traffic will not be processed */

 /*
  * ecm_front_end_ipv4_interface_construct_ip_addr_set()
  *	Sets the IP addresses.
  *
  * Sets the ip address fields of the ecm_front_end_interface_construct_instance
  * with the given ip addresses.
  */
 static void ecm_front_end_ipv4_interface_construct_ip_addr_set(struct ecm_front_end_interface_construct_instance *efeici,
 							ip_addr_t from_mac_lookup, ip_addr_t to_mac_lookup,
 							ip_addr_t from_nat_mac_lookup, ip_addr_t to_nat_mac_lookup)
 {
 	ECM_IP_ADDR_COPY(efeici->from_mac_lookup_ip_addr, from_mac_lookup);
 	ECM_IP_ADDR_COPY(efeici->to_mac_lookup_ip_addr, to_mac_lookup);
 	ECM_IP_ADDR_COPY(efeici->from_nat_mac_lookup_ip_addr, from_nat_mac_lookup);
 	ECM_IP_ADDR_COPY(efeici->to_nat_mac_lookup_ip_addr, to_nat_mac_lookup);
 }

 /*
  * ecm_front_end_ipv4_interface_construct_netdev_set()
  *	Sets the net devices.
  *
  * Sets the net device fields of the ecm_front_end_interface_construct_instance
  * with the given net devices.
  */
 static void ecm_front_end_ipv4_interface_construct_netdev_set(struct ecm_front_end_interface_construct_instance *efeici,
 							struct net_device *from, struct net_device *from_other,
 							struct net_device *to, struct net_device *to_other,
 							struct net_device *from_nat, struct net_device *from_nat_other,
 							struct net_device *to_nat, struct net_device *to_nat_other)
 {
 	efeici->from_dev = from;
 	efeici->from_other_dev = from_other;
 	efeici->to_dev = to;
 	efeici->to_other_dev = to_other;
 	efeici->from_nat_dev = from_nat;
 	efeici->from_nat_other_dev = from_nat_other;
 	efeici->to_nat_dev = to_nat;
 	efeici->to_nat_other_dev = to_nat_other;
 }

 /*
  * ecm_front_end_ipv4_interface_construct_netdev_put()
  *	Release the references of the net devices.
  */
 void ecm_front_end_ipv4_interface_construct_netdev_put(struct ecm_front_end_interface_construct_instance *efeici)
 {
 	dev_put(efeici->from_dev);
 	dev_put(efeici->from_other_dev);
 	dev_put(efeici->to_dev);
 	dev_put(efeici->to_other_dev);
 	dev_put(efeici->from_nat_dev);
 	dev_put(efeici->from_nat_other_dev);
 	dev_put(efeici->to_nat_dev);
 	dev_put(efeici->to_nat_other_dev);
 }

 /*
  * ecm_front_end_ipv4_interface_construct_netdev_hold()
  *	Holds the references of the netdevices.
  */
 void ecm_front_end_ipv4_interface_construct_netdev_hold(struct ecm_front_end_interface_construct_instance *efeici)
 {
 	dev_hold(efeici->from_dev);
 	dev_hold(efeici->from_other_dev);
 	dev_hold(efeici->to_dev);
 	dev_hold(efeici->to_other_dev);
 	dev_hold(efeici->from_nat_dev);
 	dev_hold(efeici->from_nat_other_dev);
 	dev_hold(efeici->to_nat_dev);
 	dev_hold(efeici->to_nat_other_dev);
 }

 /*
  * ecm_front_end_ipv4_interface_construct_set_and_hold()
  *	Sets the IPv4 ECM front end interface construct instance,
  *	and holds the net devices.
  */
 bool ecm_front_end_ipv4_interface_construct_set_and_hold(struct sk_buff *skb, ecm_tracker_sender_type_t sender, ecm_db_direction_t ecm_dir, bool is_routed,
 							struct net_device *in_dev, struct net_device *out_dev,
 							ip_addr_t ip_src_addr, ip_addr_t ip_src_addr_nat,
 							ip_addr_t ip_dest_addr, ip_addr_t ip_dest_addr_nat,
 							struct ecm_front_end_interface_construct_instance *efeici)
 {
 	struct dst_entry *dst = skb_dst(skb);
 	struct rtable *rt = (struct rtable *)dst;
 	struct net_device *rt_iif_dev = NULL;
 	ip_addr_t rt_dst_addr;
 	struct net_device *from = NULL;
 	struct net_device *from_other = NULL;
 	struct net_device *to = NULL;
 	struct net_device *to_other = NULL;
 	struct net_device *from_nat = NULL;
 	struct net_device *from_nat_other = NULL;
 	struct net_device *to_nat = NULL;
 	struct net_device *to_nat_other = NULL;
 	struct net_device *dst_dev = NULL;
 	ip_addr_t from_mac_lookup;
 	ip_addr_t to_mac_lookup;
 	ip_addr_t from_nat_mac_lookup;
 	ip_addr_t to_nat_mac_lookup;
 	bool gateway = false;
 	bool dst_dev_override = false;

 	/*
 	 * Set the rt_dst_addr with the destination IP address by default.
 	 * If there is a gateway IP address, this will be overwritten with the gateway IP address.
 	 */
 	ECM_IP_ADDR_COPY(rt_dst_addr, ip_dest_addr);

 	if (!is_routed) {
 		/*
 		 * Bridged
 		 */
 		from = in_dev;
 		from_other = in_dev;
 		to = out_dev;
 		to_other = out_dev;
 	} else {
 		__be32 rt_gw4;

 		if (!rt) {
 			DEBUG_WARN("rtable is NULL\n");
 			return false;
 		}

 		/*
 		 * If the flow is routed, extract the route information from the skb.
 		 * Print the extracted information for debug purpose.
 		 */
 		rt_iif_dev = dev_get_by_index(&init_net, skb->skb_iif);
 		if (!rt_iif_dev) {
 			DEBUG_WARN("No rt_iif dev\n");
 			return false;
 		}
 #if (LINUX_VERSION_CODE <= KERNEL_VERSION(5, 2, 0))
 		rt_gw4 = rt->rt_gateway;
 #else
 		rt_gw4 = rt->rt_gw4;
 #endif
 		dst_dev = dst->dev;

 #ifdef ECM_XFRM_ENABLE
 		/*
 		 * If the dst is an xfrm dst, then override the dst_dev.
 		*/
 		if (dst_xfrm(dst)) {
 			int32_t if_type;
 			struct net_device *xfrm_dst_dev = ecm_interface_get_and_hold_ipsec_tun_netdev(NULL, skb, &if_type);
 			/*
 			 * If we reach here and are unable to find the tunnel netdevice,
 			 * then return failure.
 			 */
 			if (!xfrm_dst_dev) {
 				return false;
 			}

 			dst_dev = xfrm_dst_dev;
 			dst_dev_override = true;
 		}

 #endif
 		DEBUG_TRACE("dst->dev: %s dst_dev: %s\n", dst->dev->name, dst_dev->name);
 		DEBUG_TRACE("%px: rt gateway: %pI4\n", rt, &rt_gw4);

 		DEBUG_INFO("ip_src_addr" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(ip_src_addr));
 		DEBUG_INFO("ip_src_addr_nat" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(ip_src_addr_nat));
 		DEBUG_INFO("ip_dest_addr" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(ip_dest_addr));
 		DEBUG_INFO("ip_dest_addr_nat" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(ip_dest_addr_nat));

 		if (rt->rt_uses_gateway || (rt->rt_flags & RTF_GATEWAY)) {
 			/*
 			 * Overwrite the rt_dst_addr with the gateway IP address. The destination host is
 			 * behind a gateway.
 			 */
 			DEBUG_TRACE("Gateway address will be looked up overwrite the rt_dst_addr\n");
 			ECM_NIN4_ADDR_TO_IP_ADDR(rt_dst_addr, rt_gw4)
 			gateway = true;
 		}

 		DEBUG_INFO("rt_dst_addr" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(rt_dst_addr));

 		/*
 		 * Initialize the interfaces with defaults.
 		 * rt_iif_dev is the interface which the packet comes in to the system,
 		 * dst->dev is the interface which the packet goes out from the system.
 		 */
 		from = rt_iif_dev;
 		from_other = dst_dev;
 		to = dst_dev;
 		to_other = rt_iif_dev;
 	}

 	/*
 	 * Just in case the is_routed flag comes as 0, but the ecm_dir is different than
 	 * bridge flow, we check the netdevices here before setting the efeici fields.
 	 *
 	 * TODO: Why ecm_dir comes as non-bridge flow, even though the is_routed flag is bridged?
 	 */
 	if (ecm_dir != ECM_DB_DIRECTION_BRIDGED) {
 		if (!dst || !dst_dev || !rt_iif_dev) {
 			DEBUG_WARN("Traffic is not bridged but the netdevs are not valid\n");
 			if (rt_iif_dev) {
 				dev_put(rt_iif_dev);
 			}
 			if (dst_dev_override) {
 				dev_put(dst_dev);
 			}
 			return false;
 		}
 	}

 	/*
 	 * Initialize the mac lookup ip addresses with defaults.
 	 */
 	ECM_IP_ADDR_COPY(from_mac_lookup, ip_src_addr);
 	ECM_IP_ADDR_COPY(to_mac_lookup, rt_dst_addr);
 	ECM_IP_ADDR_COPY(from_nat_mac_lookup, ip_src_addr_nat);

 	/*
 	 * If we have a gateway IP address we should use it for the
 	 * to_nat_mac_lookup IP address.
 	 * Note that in hairpin NAT the destination IP address and the destination
 	 * NAT IP addresses are different than each other. Because of this we cannot
 	 * use the rt_dst_addr for to_nat_mac_lookup as well. In a normal routing
 	 * traffic they are equal.
 	 */
 	if (gateway) {
 		ECM_IP_ADDR_COPY(to_nat_mac_lookup, rt_dst_addr);
 	} else {
 		ECM_IP_ADDR_COPY(to_nat_mac_lookup, ip_dest_addr_nat);
 	}

 	/*
 	 * Based on the flow and connection direction, set the NAT'd net devices.
 	 * The above IP address settings are valid for each flow and connection direction case.
 	 */
 	if (sender == ECM_TRACKER_SENDER_TYPE_SRC) {
 		if (ecm_dir == ECM_DB_DIRECTION_EGRESS_NAT) {
 			from_nat = dst_dev;
 			from_nat_other = rt_iif_dev;
 			to_nat = dst_dev;
 			to_nat_other = rt_iif_dev;
 		} else if (ecm_dir == ECM_DB_DIRECTION_NON_NAT) {
 			from_nat = rt_iif_dev;
 			from_nat_other = dst_dev;
 			to_nat = dst_dev;
 			to_nat_other = rt_iif_dev;
 		} else if (ecm_dir == ECM_DB_DIRECTION_INGRESS_NAT) {
 			from_nat = rt_iif_dev;
 			from_nat_other = dst_dev;
 			to_nat = rt_iif_dev;
 			to_nat_other = dst_dev;
 		} else if (ecm_dir == ECM_DB_DIRECTION_BRIDGED) {
 			from_nat = in_dev;
 			from_nat_other = in_dev;
 			to_nat = out_dev;
 			to_nat_other = out_dev;
 		} else {
 			DEBUG_ASSERT(false, "Unhandled ecm_dir: %d\n", ecm_dir);
 		}
 	} else {
 		if (ecm_dir == ECM_DB_DIRECTION_EGRESS_NAT) {
 			from_nat = rt_iif_dev;
 			from_nat_other = dst_dev;
 			to_nat = rt_iif_dev;
 			to_nat_other = dst_dev;
 		} else if (ecm_dir == ECM_DB_DIRECTION_NON_NAT) {
 			from_nat = rt_iif_dev;
 			from_nat_other = dst_dev;
 			to_nat = dst_dev;
 			to_nat_other = rt_iif_dev;
 		} else if (ecm_dir == ECM_DB_DIRECTION_INGRESS_NAT) {
 			from_nat = dst_dev;
 			from_nat_other = rt_iif_dev;
 			to_nat = dst_dev;
 			to_nat_other = rt_iif_dev;
 		} else if (ecm_dir == ECM_DB_DIRECTION_BRIDGED) {
 			from_nat = in_dev;
 			from_nat_other = in_dev;
 			to_nat = out_dev;
 			to_nat_other = out_dev;
 		} else {
 			DEBUG_ASSERT(false, "Unhandled ecm_dir: %d\n", ecm_dir);
 		}
 	}

 	ecm_front_end_ipv4_interface_construct_netdev_set(efeici, from, from_other,
 								to, to_other,
 								from_nat, from_nat_other,
 								to_nat, to_nat_other);

 	ecm_front_end_ipv4_interface_construct_netdev_hold(efeici);

 	ecm_front_end_ipv4_interface_construct_ip_addr_set(efeici, from_mac_lookup, to_mac_lookup,
 								from_nat_mac_lookup, to_nat_mac_lookup);

 	if (dst_dev_override) {
 		dev_put(dst_dev);
 	}

 	/*
 	 * Release the iff_dev which was hold by the dev_get_by_index() call.
 	 */
 	if (rt_iif_dev) {
 		dev_put(rt_iif_dev);
 	}

 	return true;
 }

 /*
  * ecm_front_end_ipv4_stop()
  */
 void ecm_front_end_ipv4_stop(int num)
 {
 	ecm_front_end_ipv4_stopped = num;
 }

 /*
  * ecm_front_end_ipv4_init()
  */
 int ecm_front_end_ipv4_init(struct dentry *dentry)
 {
 	if (!debugfs_create_u32("front_end_ipv4_stop", S_IRUGO | S_IWUSR, dentry,
 					(u32 *)&ecm_front_end_ipv4_stopped)) {
 		DEBUG_ERROR("Failed to create ecm front end ipv4 stop file in debugfs\n");
 		return -1;
 	}

 	return ecm_ipv4_init(dentry);
 }

 /*
  * ecm_front_end_ipv4_exit()
  */
 void ecm_front_end_ipv4_exit(void)
 {
 	ecm_ipv4_exit();
 }
	/*
	**************************************************************************
	* Copyright (c) 2015-2016, 2020-2021 The Linux Foundation. All rights reserved.
	* Permission to use, copy, modify, and/or distribute this software for
	* any purpose with or without fee is hereby granted, provided that the
	* above copyright notice and this permission notice appear in all copies.
	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
	* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
	* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
	* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	**************************************************************************
	*/

	#include <linux/version.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/debugfs.h>
	#include <linux/inet.h>
	#include <linux/etherdevice.h>
	#include <net/netfilter/nf_conntrack.h>
	#include <net/ip.h>
	#include <net/ipv6.h>
	#include <net/route.h>

	/*
	* Debug output levels
	* 0 = OFF
	* 1 = ASSERTS / ERRORS
	* 2 = 1 + WARN
	* 3 = 2 + INFO
	* 4 = 3 + TRACE
	*/
	#define DEBUG_LEVEL ECM_FRONT_END_IPV4_DEBUG_LEVEL

	#include "ecm_types.h"
	#include "ecm_db_types.h"
	#include "ecm_state.h"
	#include "ecm_tracker.h"
	#include "ecm_classifier.h"
	#include "ecm_front_end_types.h"
	#include "ecm_tracker_datagram.h"
	#include "ecm_tracker_udp.h"
	#include "ecm_tracker_tcp.h"
	#include "ecm_db.h"
	#include "ecm_front_end_ipv4.h"
	#include "ecm_interface.h"
	#include "ecm_ipv4.h"

	/*
	* General operational control
	*/
	int ecm_front_end_ipv4_stopped = 0; /* When non-zero further traffic will not be processed */

	/*
	* ecm_front_end_ipv4_interface_construct_ip_addr_set()
	* Sets the IP addresses.
	*
	* Sets the ip address fields of the ecm_front_end_interface_construct_instance
	* with the given ip addresses.
	*/
	static void ecm_front_end_ipv4_interface_construct_ip_addr_set(struct ecm_front_end_interface_construct_instance *efeici,
	ip_addr_t from_mac_lookup, ip_addr_t to_mac_lookup,
	ip_addr_t from_nat_mac_lookup, ip_addr_t to_nat_mac_lookup)
	{
	ECM_IP_ADDR_COPY(efeici->from_mac_lookup_ip_addr, from_mac_lookup);
	ECM_IP_ADDR_COPY(efeici->to_mac_lookup_ip_addr, to_mac_lookup);
	ECM_IP_ADDR_COPY(efeici->from_nat_mac_lookup_ip_addr, from_nat_mac_lookup);
	ECM_IP_ADDR_COPY(efeici->to_nat_mac_lookup_ip_addr, to_nat_mac_lookup);
	}

	/*
	* ecm_front_end_ipv4_interface_construct_netdev_set()
	* Sets the net devices.
	*
	* Sets the net device fields of the ecm_front_end_interface_construct_instance
	* with the given net devices.
	*/
	static void ecm_front_end_ipv4_interface_construct_netdev_set(struct ecm_front_end_interface_construct_instance *efeici,
	struct net_device from, struct net_device from_other,
	struct net_device to, struct net_device to_other,
	struct net_device from_nat, struct net_device from_nat_other,
	struct net_device to_nat, struct net_device to_nat_other)
	{
	efeici->from_dev = from;
	efeici->from_other_dev = from_other;
	efeici->to_dev = to;
	efeici->to_other_dev = to_other;
	efeici->from_nat_dev = from_nat;
	efeici->from_nat_other_dev = from_nat_other;
	efeici->to_nat_dev = to_nat;
	efeici->to_nat_other_dev = to_nat_other;
	}

	/*
	* ecm_front_end_ipv4_interface_construct_netdev_put()
	* Release the references of the net devices.
	*/
	void ecm_front_end_ipv4_interface_construct_netdev_put(struct ecm_front_end_interface_construct_instance *efeici)
	{
	dev_put(efeici->from_dev);
	dev_put(efeici->from_other_dev);
	dev_put(efeici->to_dev);
	dev_put(efeici->to_other_dev);
	dev_put(efeici->from_nat_dev);
	dev_put(efeici->from_nat_other_dev);
	dev_put(efeici->to_nat_dev);
	dev_put(efeici->to_nat_other_dev);
	}

	/*
	* ecm_front_end_ipv4_interface_construct_netdev_hold()
	* Holds the references of the netdevices.
	*/
	void ecm_front_end_ipv4_interface_construct_netdev_hold(struct ecm_front_end_interface_construct_instance *efeici)
	{
	dev_hold(efeici->from_dev);
	dev_hold(efeici->from_other_dev);
	dev_hold(efeici->to_dev);
	dev_hold(efeici->to_other_dev);
	dev_hold(efeici->from_nat_dev);
	dev_hold(efeici->from_nat_other_dev);
	dev_hold(efeici->to_nat_dev);
	dev_hold(efeici->to_nat_other_dev);
	}

	/*
	* ecm_front_end_ipv4_interface_construct_set_and_hold()
	* Sets the IPv4 ECM front end interface construct instance,
	* and holds the net devices.
	*/
	bool ecm_front_end_ipv4_interface_construct_set_and_hold(struct sk_buff *skb, ecm_tracker_sender_type_t sender, ecm_db_direction_t ecm_dir, bool is_routed,
	struct net_device in_dev, struct net_device out_dev,
	ip_addr_t ip_src_addr, ip_addr_t ip_src_addr_nat,
	ip_addr_t ip_dest_addr, ip_addr_t ip_dest_addr_nat,
	struct ecm_front_end_interface_construct_instance *efeici)
	{
	struct dst_entry *dst = skb_dst(skb);
	struct rtable rt = (struct rtable )dst;
	struct net_device *rt_iif_dev = NULL;
	ip_addr_t rt_dst_addr;
	struct net_device *from = NULL;
	struct net_device *from_other = NULL;
	struct net_device *to = NULL;
	struct net_device *to_other = NULL;
	struct net_device *from_nat = NULL;
	struct net_device *from_nat_other = NULL;
	struct net_device *to_nat = NULL;
	struct net_device *to_nat_other = NULL;
	struct net_device *dst_dev = NULL;
	ip_addr_t from_mac_lookup;
	ip_addr_t to_mac_lookup;
	ip_addr_t from_nat_mac_lookup;
	ip_addr_t to_nat_mac_lookup;
	bool gateway = false;
	bool dst_dev_override = false;

	/*
	* Set the rt_dst_addr with the destination IP address by default.
	* If there is a gateway IP address, this will be overwritten with the gateway IP address.
	*/
	ECM_IP_ADDR_COPY(rt_dst_addr, ip_dest_addr);

	if (!is_routed) {
	/*
	* Bridged
	*/
	from = in_dev;
	from_other = in_dev;
	to = out_dev;
	to_other = out_dev;
	} else {
	__be32 rt_gw4;

	if (!rt) {
	DEBUG_WARN("rtable is NULL\n");
	return false;
	}

	/*
	* If the flow is routed, extract the route information from the skb.
	* Print the extracted information for debug purpose.
	*/
	rt_iif_dev = dev_get_by_index(&init_net, skb->skb_iif);
	if (!rt_iif_dev) {
	DEBUG_WARN("No rt_iif dev\n");
	return false;
	}
	#if (LINUX_VERSION_CODE <= KERNEL_VERSION(5, 2, 0))
	rt_gw4 = rt->rt_gateway;
	#else
	rt_gw4 = rt->rt_gw4;
	#endif
	dst_dev = dst->dev;

	#ifdef ECM_XFRM_ENABLE
	/*
	* If the dst is an xfrm dst, then override the dst_dev.
	*/
	if (dst_xfrm(dst)) {
	int32_t if_type;
	struct net_device *xfrm_dst_dev = ecm_interface_get_and_hold_ipsec_tun_netdev(NULL, skb, &if_type);
	/*
	* If we reach here and are unable to find the tunnel netdevice,
	* then return failure.
	*/
	if (!xfrm_dst_dev) {
	return false;
	}

	dst_dev = xfrm_dst_dev;
	dst_dev_override = true;
	}

	#endif
	DEBUG_TRACE("dst->dev: %s dst_dev: %s\n", dst->dev->name, dst_dev->name);
	DEBUG_TRACE("%px: rt gateway: %pI4\n", rt, &rt_gw4);

	DEBUG_INFO("ip_src_addr" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(ip_src_addr));
	DEBUG_INFO("ip_src_addr_nat" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(ip_src_addr_nat));
	DEBUG_INFO("ip_dest_addr" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(ip_dest_addr));
	DEBUG_INFO("ip_dest_addr_nat" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(ip_dest_addr_nat));

	if (rt->rt_uses_gateway \|\| (rt->rt_flags & RTF_GATEWAY)) {
	/*
	* Overwrite the rt_dst_addr with the gateway IP address. The destination host is
	* behind a gateway.
	*/
	DEBUG_TRACE("Gateway address will be looked up overwrite the rt_dst_addr\n");
	ECM_NIN4_ADDR_TO_IP_ADDR(rt_dst_addr, rt_gw4)
	gateway = true;
	}

	DEBUG_INFO("rt_dst_addr" ECM_IP_ADDR_DOT_FMT "\n", ECM_IP_ADDR_TO_DOT(rt_dst_addr));

	/*
	* Initialize the interfaces with defaults.
	* rt_iif_dev is the interface which the packet comes in to the system,
	* dst->dev is the interface which the packet goes out from the system.
	*/
	from = rt_iif_dev;
	from_other = dst_dev;
	to = dst_dev;
	to_other = rt_iif_dev;
	}

	/*
	* Just in case the is_routed flag comes as 0, but the ecm_dir is different than
	* bridge flow, we check the netdevices here before setting the efeici fields.
	*
	* TODO: Why ecm_dir comes as non-bridge flow, even though the is_routed flag is bridged?
	*/
	if (ecm_dir != ECM_DB_DIRECTION_BRIDGED) {
	if (!dst \|\| !dst_dev \|\| !rt_iif_dev) {
	DEBUG_WARN("Traffic is not bridged but the netdevs are not valid\n");
	if (rt_iif_dev) {
	dev_put(rt_iif_dev);
	}
	if (dst_dev_override) {
	dev_put(dst_dev);
	}
	return false;
	}
	}

	/*
	* Initialize the mac lookup ip addresses with defaults.
	*/
	ECM_IP_ADDR_COPY(from_mac_lookup, ip_src_addr);
	ECM_IP_ADDR_COPY(to_mac_lookup, rt_dst_addr);
	ECM_IP_ADDR_COPY(from_nat_mac_lookup, ip_src_addr_nat);

	/*
	* If we have a gateway IP address we should use it for the
	* to_nat_mac_lookup IP address.
	* Note that in hairpin NAT the destination IP address and the destination
	* NAT IP addresses are different than each other. Because of this we cannot
	* use the rt_dst_addr for to_nat_mac_lookup as well. In a normal routing
	* traffic they are equal.
	*/
	if (gateway) {
	ECM_IP_ADDR_COPY(to_nat_mac_lookup, rt_dst_addr);
	} else {
	ECM_IP_ADDR_COPY(to_nat_mac_lookup, ip_dest_addr_nat);
	}

	/*
	* Based on the flow and connection direction, set the NAT'd net devices.
	* The above IP address settings are valid for each flow and connection direction case.
	*/
	if (sender == ECM_TRACKER_SENDER_TYPE_SRC) {
	if (ecm_dir == ECM_DB_DIRECTION_EGRESS_NAT) {
	from_nat = dst_dev;
	from_nat_other = rt_iif_dev;
	to_nat = dst_dev;
	to_nat_other = rt_iif_dev;
	} else if (ecm_dir == ECM_DB_DIRECTION_NON_NAT) {
	from_nat = rt_iif_dev;
	from_nat_other = dst_dev;
	to_nat = dst_dev;
	to_nat_other = rt_iif_dev;
	} else if (ecm_dir == ECM_DB_DIRECTION_INGRESS_NAT) {
	from_nat = rt_iif_dev;
	from_nat_other = dst_dev;
	to_nat = rt_iif_dev;
	to_nat_other = dst_dev;
	} else if (ecm_dir == ECM_DB_DIRECTION_BRIDGED) {
	from_nat = in_dev;
	from_nat_other = in_dev;
	to_nat = out_dev;
	to_nat_other = out_dev;
	} else {
	DEBUG_ASSERT(false, "Unhandled ecm_dir: %d\n", ecm_dir);
	}
	} else {
	if (ecm_dir == ECM_DB_DIRECTION_EGRESS_NAT) {
	from_nat = rt_iif_dev;
	from_nat_other = dst_dev;
	to_nat = rt_iif_dev;
	to_nat_other = dst_dev;
	} else if (ecm_dir == ECM_DB_DIRECTION_NON_NAT) {
	from_nat = rt_iif_dev;
	from_nat_other = dst_dev;
	to_nat = dst_dev;
	to_nat_other = rt_iif_dev;
	} else if (ecm_dir == ECM_DB_DIRECTION_INGRESS_NAT) {
	from_nat = dst_dev;
	from_nat_other = rt_iif_dev;
	to_nat = dst_dev;
	to_nat_other = rt_iif_dev;
	} else if (ecm_dir == ECM_DB_DIRECTION_BRIDGED) {
	from_nat = in_dev;
	from_nat_other = in_dev;
	to_nat = out_dev;
	to_nat_other = out_dev;
	} else {
	DEBUG_ASSERT(false, "Unhandled ecm_dir: %d\n", ecm_dir);
	}
	}

	ecm_front_end_ipv4_interface_construct_netdev_set(efeici, from, from_other,
	to, to_other,
	from_nat, from_nat_other,
	to_nat, to_nat_other);

	ecm_front_end_ipv4_interface_construct_netdev_hold(efeici);

	ecm_front_end_ipv4_interface_construct_ip_addr_set(efeici, from_mac_lookup, to_mac_lookup,
	from_nat_mac_lookup, to_nat_mac_lookup);

	if (dst_dev_override) {
	dev_put(dst_dev);
	}

	/*
	* Release the iff_dev which was hold by the dev_get_by_index() call.
	*/
	if (rt_iif_dev) {
	dev_put(rt_iif_dev);
	}

	return true;
	}

	/*
	* ecm_front_end_ipv4_stop()
	*/
	void ecm_front_end_ipv4_stop(int num)
	{
	ecm_front_end_ipv4_stopped = num;
	}

	/*
	* ecm_front_end_ipv4_init()
	*/
	int ecm_front_end_ipv4_init(struct dentry *dentry)
	{
	if (!debugfs_create_u32("front_end_ipv4_stop", S_IRUGO \| S_IWUSR, dentry,
	(u32 *)&ecm_front_end_ipv4_stopped)) {
	DEBUG_ERROR("Failed to create ecm front end ipv4 stop file in debugfs\n");
	return -1;
	}

	return ecm_ipv4_init(dentry);
	}

	/*
	* ecm_front_end_ipv4_exit()
	*/
	void ecm_front_end_ipv4_exit(void)
	{
	ecm_ipv4_exit();
	}