/**************************************************************************** * net/nat/nat.h * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ #ifndef __NET_NAT_NAT_H #define __NET_NAT_NAT_H /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #if defined(CONFIG_NET_NAT) && defined(CONFIG_NET_IPv4) /**************************************************************************** * Public Types ****************************************************************************/ struct ipv4_nat_entry { /* Support for doubly-linked lists. * * TODO: Implement a general hash table, and use it to optimize performance * here. */ FAR struct ipv4_nat_entry *flink; FAR struct ipv4_nat_entry *blink; /* Local Network External Network * |----------------| * | | external port> peer port> * |----------------| * * Full cone NAT on single WAN only need to save local ip:port and external * port. For ICMP, save id in port field. */ in_addr_t local_ip; /* IP address of the local (private) host. */ uint16_t local_port; /* Port of the local (private) host. */ uint16_t external_port; /* The external port of local (private) host. */ uint8_t protocol; /* L4 protocol (TCP, UDP etc). */ uint32_t expire_time; /* The expiration time of this entry. */ }; /**************************************************************************** * Public Function Prototypes ****************************************************************************/ /**************************************************************************** * Name: ipv4_nat_enable * * Description: * Enable NAT function on a network device. * * Input Parameters: * dev - The device on which the outbound packets will be masqueraded. * * Returned Value: * Zero is returned if NAT function is successfully enabled on the device; * A negated errno value is returned if failed. * * Assumptions: * NAT will only be enabled on at most one device. * * Limitations: * External ports are not isolated between devices yet, so if NAT is * enabled on more than one device, an external port used on one device * will also be used by same local ip:port on another device. * ****************************************************************************/ int ipv4_nat_enable(FAR struct net_driver_s *dev); /**************************************************************************** * Name: ipv4_nat_disable * * Description: * Disable NAT function on a network device. * * Input Parameters: * dev - The device on which the NAT function will be disabled. * * Returned Value: * Zero is returned if NAT function is successfully disabled on the device; * A negated errno value is returned if failed. * ****************************************************************************/ int ipv4_nat_disable(FAR struct net_driver_s *dev); /**************************************************************************** * Name: ipv4_nat_inbound * * Description: * Check if a received packet belongs to a NAT entry. If so, translate it. * * Input Parameters: * dev - The device on which the packet is received. * ipv4 - Points to the IPv4 header with dev->d_buf. * * Returned Value: * Zero is returned if NAT is successfully applied, or is not enabled for * this packet; * A negated errno value is returned if error occured. * ****************************************************************************/ int ipv4_nat_inbound(FAR struct net_driver_s *dev, FAR struct ipv4_hdr_s *ipv4); /**************************************************************************** * Name: ipv4_nat_outbound * * Description: * Check if we want to perform NAT with this outbound packet before sending * it. If so, translate it. * * Input Parameters: * dev - The device on which the packet will be sent. * ipv4 - Points to the IPv4 header to be filled into dev->d_buf later. * * Returned Value: * Zero is returned if NAT is successfully applied, or is not enabled for * this packet; * A negated errno value is returned if error occured. * ****************************************************************************/ int ipv4_nat_outbound(FAR struct net_driver_s *dev, FAR struct ipv4_hdr_s *ipv4); /**************************************************************************** * Name: ipv4_nat_port_inuse * * Description: * Check whether a port is currently used by NAT. * * Input Parameters: * protocol - The L4 protocol of the packet. * ip - The IP bind with the port (in network byte order). * port - The port number to check (in network byte order). * * Returned Value: * True if the port is already used by NAT, otherwise false. * ****************************************************************************/ bool ipv4_nat_port_inuse(uint8_t protocol, in_addr_t ip, uint16_t port); /**************************************************************************** * Name: ipv4_nat_inbound_entry_find * * Description: * Find the inbound entry in NAT entry list. * * Input Parameters: * protocol - The L4 protocol of the packet. * external_port - The external port of the packet. * refresh - Whether to refresh the selected entry. * * Returned Value: * Pointer to entry on success; null on failure * ****************************************************************************/ FAR struct ipv4_nat_entry * ipv4_nat_inbound_entry_find(uint8_t protocol, uint16_t external_port, bool refresh); /**************************************************************************** * Name: ipv4_nat_outbound_entry_find * * Description: * Find the outbound entry in NAT entry list. Create one if corresponding * entry does not exist. * * Input Parameters: * dev - The device on which the packet will be sent. * protocol - The L4 protocol of the packet. * local_ip - The local ip of the packet. * local_port - The local port of the packet. * * Returned Value: * Pointer to entry on success; null on failure * ****************************************************************************/ FAR struct ipv4_nat_entry * ipv4_nat_outbound_entry_find(FAR struct net_driver_s *dev, uint8_t protocol, in_addr_t local_ip, uint16_t local_port); #endif /* CONFIG_NET_NAT && CONFIG_NET_IPv4 */ #endif /* __NET_NAT_NAT_H */