852 lines
27 KiB
C
852 lines
27 KiB
C
/****************************************************************************
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* net/nat/ipv4_nat.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <assert.h>
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#include <debug.h>
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#include <errno.h>
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#include <stdint.h>
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#include <string.h>
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#include <sys/types.h>
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#include <nuttx/net/icmp.h>
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#include <nuttx/net/tcp.h>
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#include <nuttx/net/udp.h>
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#include "nat/nat.h"
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#include "utils/utils.h"
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#if defined(CONFIG_NET_NAT) && defined(CONFIG_NET_IPv4)
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Adjust checksums in headers. */
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#define chksum_adjust(chksum,optr,nptr,len) \
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net_chksum_adjust((FAR uint16_t *)(chksum), (FAR uint16_t *)(optr), len, \
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(FAR uint16_t *)(nptr), len)
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/* Getting IP & Port to manipulate from L3/L4 header. */
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#define MANIP_IPADDR(iphdr,manip_type) \
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((manip_type) == NAT_MANIP_SRC ? (iphdr)->srcipaddr : (iphdr)->destipaddr)
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#define MANIP_PORT(l4hdr,manip_type) \
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((manip_type) == NAT_MANIP_SRC ? &(l4hdr)->srcport : &(l4hdr)->destport)
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/* Getting L4 header from IPv4 header. */
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#define L4_HDR(ipv4) \
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(FAR void *)((FAR uint8_t *)(ipv4) + (((ipv4)->vhl & IPv4_HLMASK) << 2))
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#define L4_HDRLEN(proto) \
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((proto) == IP_PROTO_TCP ? TCP_HDRLEN : \
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(proto) == IP_PROTO_UDP ? UDP_HDRLEN : ICMP_HDRLEN)
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#if defined(CONFIG_NET_TCP)
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# define L4_MAXHDRLEN TCP_HDRLEN
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#elif defined(CONFIG_NET_UDP)
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# define L4_MAXHDRLEN UDP_HDRLEN
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#elif defined(CONFIG_NET_ICMP)
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# define L4_MAXHDRLEN ICMP_HDRLEN
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#endif
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static FAR struct ipv4_nat_entry *
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ipv4_nat_inbound_internal(FAR struct ipv4_hdr_s *ipv4,
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enum nat_manip_type_e manip_type);
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static FAR struct ipv4_nat_entry *
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ipv4_nat_outbound_internal(FAR struct net_driver_s *dev,
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FAR struct ipv4_hdr_s *ipv4,
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enum nat_manip_type_e manip_type);
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: ipv4_nat_ip_adjust
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*
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* Description:
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* Adjust address and checksum for network packet.
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*
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* Input Parameters:
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* ipv4 - Points to the IPv4 header to adjust.
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* l4chksum - Points to the L4 checksum to adjust, NULL for not adjust.
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* new_ip - The IP to set into header.
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* manip_type - Whether manipulate source ip or destination ip.
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*
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****************************************************************************/
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static void ipv4_nat_ip_adjust(FAR struct ipv4_hdr_s *ipv4,
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FAR uint16_t *l4chksum, in_addr_t new_ip,
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enum nat_manip_type_e manip_type)
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{
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FAR uint16_t *old_ip = MANIP_IPADDR(ipv4, manip_type);
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if (l4chksum != NULL)
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{
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chksum_adjust(l4chksum, old_ip, &new_ip, sizeof(new_ip));
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}
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chksum_adjust(&ipv4->ipchksum, old_ip, &new_ip, sizeof(new_ip));
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net_ipv4addr_hdrcopy(old_ip, &new_ip);
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}
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/****************************************************************************
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* Name: ipv4_nat_port_adjust
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*
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* Description:
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* Adjust port and checksum for network packet.
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*
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* Input Parameters:
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* l4chksum - Points to the L4 checksum to adjust, NULL for not adjust.
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* old_port - The port to be set.
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* new_port - The port to set into header.
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*
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****************************************************************************/
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static void ipv4_nat_port_adjust(FAR uint16_t *l4chksum,
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FAR uint16_t *old_port, uint16_t new_port)
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{
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if (l4chksum != NULL)
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{
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chksum_adjust(l4chksum, old_port, &new_port, sizeof(new_port));
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}
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*old_port = new_port;
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}
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/****************************************************************************
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* Name: ipv4_nat_inbound_tcp
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*
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* Description:
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* Check if a received TCP packet belongs to a NAT entry. If so, translate
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* the external IP/Port to local IP/Port.
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*
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* Input Parameters:
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* ipv4 - Points to the IPv4 header to translate.
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* manip_type - Whether external IP/Port is in source or destination.
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*
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* Returned Value:
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* The corresponding NAT entry of the packet.
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*
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* Assumptions:
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* Packet is received on NAT device and is targeting at the address
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* assigned to the device.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_TCP
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static FAR struct ipv4_nat_entry *
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ipv4_nat_inbound_tcp(FAR struct ipv4_hdr_s *ipv4,
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enum nat_manip_type_e manip_type)
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{
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FAR struct tcp_hdr_s *tcp = L4_HDR(ipv4);
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FAR uint16_t *external_ip = MANIP_IPADDR(ipv4, manip_type);
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FAR uint16_t *external_port = MANIP_PORT(tcp, manip_type);
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FAR struct ipv4_nat_entry *entry =
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ipv4_nat_inbound_entry_find(IP_PROTO_TCP,
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net_ip4addr_conv32(external_ip),
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*external_port, true);
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if (!entry)
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{
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return NULL;
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}
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/* Note: Field tcpchksum is not guaranteed exists in TCP header inside
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* ICMP Error MSG, but we manually guarantee that it is inside valid memory
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* address (IOB >= IP + ICMP + IP + TCP), so we can update it safely.
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*/
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ipv4_nat_port_adjust(&tcp->tcpchksum, external_port, entry->local_port);
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ipv4_nat_ip_adjust(ipv4, &tcp->tcpchksum, entry->local_ip, manip_type);
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return entry;
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}
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#endif
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/****************************************************************************
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* Name: ipv4_nat_inbound_udp
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*
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* Description:
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* Check if a received UDP packet belongs to a NAT entry. If so, translate
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* the external IP/Port to local IP/Port.
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*
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* Input Parameters:
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* ipv4 - Points to the IPv4 header to translate.
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* manip_type - Whether external IP/Port is in source or destination.
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*
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* Returned Value:
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* The corresponding NAT entry of the packet.
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*
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* Assumptions:
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* Packet is received on NAT device and is targeting at the address
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* assigned to the device.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_UDP
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static FAR struct ipv4_nat_entry *
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ipv4_nat_inbound_udp(FAR struct ipv4_hdr_s *ipv4,
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enum nat_manip_type_e manip_type)
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{
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FAR struct udp_hdr_s *udp = L4_HDR(ipv4);
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FAR uint16_t *external_ip = MANIP_IPADDR(ipv4, manip_type);
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FAR uint16_t *external_port = MANIP_PORT(udp, manip_type);
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FAR uint16_t *udpchksum;
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FAR struct ipv4_nat_entry *entry =
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ipv4_nat_inbound_entry_find(IP_PROTO_UDP,
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net_ip4addr_conv32(external_ip),
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*external_port, true);
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if (!entry)
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{
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return NULL;
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}
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/* UDP checksum has special case 0 (no checksum) */
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udpchksum = udp->udpchksum != 0 ? &udp->udpchksum : NULL;
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ipv4_nat_port_adjust(udpchksum, external_port, entry->local_port);
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ipv4_nat_ip_adjust(ipv4, udpchksum, entry->local_ip, manip_type);
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return entry;
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}
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#endif
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/****************************************************************************
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* Name: ipv4_nat_inbound_icmp
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*
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* Description:
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* Check if a received ICMP packet belongs to a NAT entry. If so, translate
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* the external IP/ID to local IP/ID.
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*
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* Input Parameters:
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* ipv4 - Points to the IPv4 header to translate.
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* manip_type - Whether external IP is in source or destination.
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*
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* Returned Value:
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* The corresponding NAT entry of the packet.
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*
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* Assumptions:
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* Packet is received on g_dev and is targeting at the address assigned to
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* g_dev.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP
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static FAR struct ipv4_nat_entry *
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ipv4_nat_inbound_icmp(FAR struct ipv4_hdr_s *ipv4,
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enum nat_manip_type_e manip_type)
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{
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FAR struct icmp_hdr_s *icmp = L4_HDR(ipv4);
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FAR uint16_t *external_ip;
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FAR struct ipv4_nat_entry *entry;
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switch (icmp->type)
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{
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case ICMP_ECHO_REQUEST:
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case ICMP_ECHO_REPLY:
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external_ip = MANIP_IPADDR(ipv4, manip_type);
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entry = ipv4_nat_inbound_entry_find(IP_PROTO_ICMP,
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net_ip4addr_conv32(external_ip),
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icmp->id, true);
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if (!entry)
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{
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return NULL;
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}
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ipv4_nat_port_adjust(&icmp->icmpchksum,
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&icmp->id, entry->local_port);
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ipv4_nat_ip_adjust(ipv4, NULL, entry->local_ip, manip_type);
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return entry;
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case ICMP_DEST_UNREACHABLE:
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case ICMP_TIME_EXCEEDED:
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case ICMP_PARAMETER_PROBLEM:
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/* ICMP Error MSG inside another ICMP Error MSG is forbidden by
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* RFC1122, Section 3.2.2, Page 38, so we only process the outermost
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* ICMP Error MSG (manip type is DST).
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*/
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if (manip_type == NAT_MANIP_DST)
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{
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/* The payload in the ICMP packet is the origin packet we sent. */
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FAR struct ipv4_hdr_s *inner =
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(FAR struct ipv4_hdr_s *)(icmp + 1);
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FAR void *inner_l4 = L4_HDR(inner);
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int16_t inner_l4len = ((ipv4->len[0] << 8) + ipv4->len[1]) -
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((intptr_t)inner_l4 - (intptr_t)ipv4);
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uint16_t inner_l4hdrbak[L4_MAXHDRLEN / 2];
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uint16_t inner_l4hdrlen;
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if (inner_l4len < 8)
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{
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/* RFC792: The original L4 data should be at least 64 bits. */
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return NULL;
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}
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/* Try backup origin L4 header for later checksum update. */
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inner_l4hdrlen = MIN(inner_l4len, L4_HDRLEN(inner->proto));
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DEBUGASSERT((intptr_t)inner_l4 - (intptr_t)ipv4 + inner_l4hdrlen
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<= CONFIG_IOB_BUFSIZE);
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memcpy(inner_l4hdrbak, inner_l4, inner_l4hdrlen);
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/* Find entry and translate inner. */
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entry = ipv4_nat_inbound_internal(inner, NAT_MANIP_SRC);
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if (!entry)
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{
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return NULL;
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}
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/* Adjust outer IP */
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ipv4_nat_ip_adjust(ipv4, NULL, entry->local_ip, manip_type);
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/* Recalculate ICMP checksum, we only need to re-calc data in L4
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* header, because the inner IPv4 header's checksum is updated,
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* and the overall checksum of IPv4 header will not change.
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*/
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chksum_adjust(&icmp->icmpchksum, inner_l4hdrbak, inner_l4,
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inner_l4hdrlen);
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return entry;
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}
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}
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return NULL;
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}
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#endif
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/****************************************************************************
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* Name: ipv4_nat_outbound_tcp
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*
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* Description:
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* Check if we want to perform NAT with this outbound TCP packet before
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* sending it. If so, translate the local IP/Port to external IP/Port.
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*
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* Input Parameters:
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* dev - The device to sent the packet (to get external IP).
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* ipv4 - Points to the IPv4 header to translate.
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* manip_type - Whether local IP/Port is in source or destination.
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*
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* Returned Value:
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* The corresponding NAT entry of the packet.
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*
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* Assumptions:
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* Packet will be sent on NAT device.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_TCP
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static FAR struct ipv4_nat_entry *
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ipv4_nat_outbound_tcp(FAR struct net_driver_s *dev,
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FAR struct ipv4_hdr_s *ipv4,
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enum nat_manip_type_e manip_type)
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{
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FAR struct tcp_hdr_s *tcp = L4_HDR(ipv4);
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FAR uint16_t *local_ip = MANIP_IPADDR(ipv4, manip_type);
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FAR uint16_t *local_port = MANIP_PORT(tcp, manip_type);
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FAR struct ipv4_nat_entry *entry;
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/* Only create entry when it's the outermost packet (manip type is SRC). */
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entry = ipv4_nat_outbound_entry_find(dev, IP_PROTO_TCP,
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net_ip4addr_conv32(local_ip), *local_port,
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(manip_type == NAT_MANIP_SRC));
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if (!entry)
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{
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return NULL;
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}
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/* Note: Field tcpchksum is not guaranteed exists in TCP header inside
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* ICMP Error MSG, but we manually guarantee that it is inside valid memory
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* address (IOB >= IP + ICMP + IP + TCP), so we can update it safely.
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*/
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ipv4_nat_port_adjust(&tcp->tcpchksum, local_port, entry->external_port);
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ipv4_nat_ip_adjust(ipv4, &tcp->tcpchksum, entry->external_ip, manip_type);
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return entry;
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}
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#endif
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/****************************************************************************
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* Name: ipv4_nat_outbound_udp
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*
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* Description:
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* Check if we want to perform NAT with this outbound UDP packet before
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* sending it. If so, translate the local IP/Port to external IP/Port.
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*
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* Input Parameters:
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* dev - The device to sent the packet (to get external IP).
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* ipv4 - Points to the IPv4 header to translate.
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* manip_type - Whether local IP/Port is in source or destination.
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*
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* Returned Value:
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* The corresponding NAT entry of the packet.
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*
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* Assumptions:
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* Packet will be sent on NAT device.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_UDP
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static FAR struct ipv4_nat_entry *
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ipv4_nat_outbound_udp(FAR struct net_driver_s *dev,
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FAR struct ipv4_hdr_s *ipv4,
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enum nat_manip_type_e manip_type)
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{
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FAR struct udp_hdr_s *udp = L4_HDR(ipv4);
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FAR uint16_t *local_ip = MANIP_IPADDR(ipv4, manip_type);
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FAR uint16_t *local_port = MANIP_PORT(udp, manip_type);
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FAR uint16_t *udpchksum;
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FAR struct ipv4_nat_entry *entry;
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/* Only create entry when it's the outermost packet (manip type is SRC). */
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entry = ipv4_nat_outbound_entry_find(dev, IP_PROTO_UDP,
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net_ip4addr_conv32(local_ip), *local_port,
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(manip_type == NAT_MANIP_SRC));
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if (!entry)
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{
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return NULL;
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}
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/* UDP checksum has special case 0 (no checksum) */
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udpchksum = udp->udpchksum != 0 ? &udp->udpchksum : NULL;
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ipv4_nat_port_adjust(udpchksum, local_port, entry->external_port);
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ipv4_nat_ip_adjust(ipv4, udpchksum, entry->external_ip, manip_type);
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return entry;
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}
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#endif
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/****************************************************************************
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* Name: ipv4_nat_outbound_icmp
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*
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* Description:
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* Check if we want to perform NAT with this outbound ICMP packet before
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* sending it. If so, translate the local IP/ID to external IP/ID.
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*
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* Input Parameters:
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* dev - The device to sent the packet (to get external IP).
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* ipv4 - Points to the IPv4 header to translate.
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* manip_type - Whether local IP is in source or destination.
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*
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* Returned Value:
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* The corresponding NAT entry of the packet.
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*
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* Assumptions:
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* Packet will be sent on NAT device.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP
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static FAR struct ipv4_nat_entry *
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ipv4_nat_outbound_icmp(FAR struct net_driver_s *dev,
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FAR struct ipv4_hdr_s *ipv4,
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enum nat_manip_type_e manip_type)
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{
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FAR struct icmp_hdr_s *icmp = L4_HDR(ipv4);
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FAR uint16_t *local_ip = MANIP_IPADDR(ipv4, manip_type);
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FAR struct ipv4_nat_entry *entry;
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switch (icmp->type)
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{
|
|
case ICMP_ECHO_REQUEST:
|
|
case ICMP_ECHO_REPLY:
|
|
|
|
/* Note: Only create new entry when it's the outermost packet (that
|
|
* is, manip type is SRC).
|
|
*/
|
|
|
|
entry = ipv4_nat_outbound_entry_find(dev, IP_PROTO_ICMP,
|
|
net_ip4addr_conv32(local_ip), icmp->id,
|
|
(manip_type == NAT_MANIP_SRC));
|
|
if (!entry)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
ipv4_nat_port_adjust(&icmp->icmpchksum,
|
|
&icmp->id, entry->external_port);
|
|
ipv4_nat_ip_adjust(ipv4, NULL, entry->external_ip, manip_type);
|
|
return entry;
|
|
|
|
case ICMP_DEST_UNREACHABLE:
|
|
case ICMP_TIME_EXCEEDED:
|
|
case ICMP_PARAMETER_PROBLEM:
|
|
/* ICMP Error MSG inside another ICMP Error MSG is forbidden by
|
|
* RFC1122, Section 3.2.2, Page 38, so we only process the outermost
|
|
* ICMP Error MSG (manip type is SRC).
|
|
*/
|
|
|
|
if (manip_type == NAT_MANIP_SRC)
|
|
{
|
|
/* The payload in the ICMP packet is the origin packet we got. */
|
|
|
|
FAR struct ipv4_hdr_s *inner =
|
|
(FAR struct ipv4_hdr_s *)(icmp + 1);
|
|
FAR void *inner_l4 = L4_HDR(inner);
|
|
int16_t inner_l4len = ((ipv4->len[0] << 8) + ipv4->len[1]) -
|
|
((intptr_t)inner_l4 - (intptr_t)ipv4);
|
|
uint16_t inner_l4hdrbak[L4_MAXHDRLEN / 2];
|
|
uint16_t inner_l4hdrlen;
|
|
|
|
if (inner_l4len < 8)
|
|
{
|
|
/* RFC792: The original L4 data should be at least 64 bits. */
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* Try backup origin L4 header for later checksum update. */
|
|
|
|
inner_l4hdrlen = MIN(inner_l4len, L4_HDRLEN(inner->proto));
|
|
DEBUGASSERT((intptr_t)inner_l4 - (intptr_t)ipv4 + inner_l4hdrlen
|
|
<= CONFIG_IOB_BUFSIZE);
|
|
memcpy(inner_l4hdrbak, inner_l4, inner_l4hdrlen);
|
|
|
|
/* Find entry and translate inner. */
|
|
|
|
entry = ipv4_nat_outbound_internal(dev, inner, NAT_MANIP_DST);
|
|
|
|
if (!entry)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
/* Adjust outer IP */
|
|
|
|
ipv4_nat_ip_adjust(ipv4, NULL, entry->external_ip, manip_type);
|
|
|
|
/* Recalculate ICMP checksum, we only need to re-calc data in L4
|
|
* header, because the inner IPv4 header's checksum is updated,
|
|
* and the overall checksum of IPv4 header will not change.
|
|
*/
|
|
|
|
chksum_adjust(&icmp->icmpchksum, inner_l4hdrbak, inner_l4,
|
|
inner_l4hdrlen);
|
|
|
|
return entry;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
/****************************************************************************
|
|
* Name: ipv4_nat_inbound_internal
|
|
*
|
|
* Description:
|
|
* Check if a received packet belongs to a NAT entry. If so, translate
|
|
* the external IP/Port to local IP/Port.
|
|
*
|
|
* Input Parameters:
|
|
* ipv4 - Points to the IPv4 header to translate.
|
|
* manip_type - Whether external IP/Port is in source or destination.
|
|
*
|
|
* Returned Value:
|
|
* The corresponding NAT entry of the packet.
|
|
*
|
|
* Assumptions:
|
|
* Packet is received on NAT device and is targeting at the address
|
|
* assigned to the device.
|
|
*
|
|
****************************************************************************/
|
|
|
|
static FAR struct ipv4_nat_entry *
|
|
ipv4_nat_inbound_internal(FAR struct ipv4_hdr_s *ipv4,
|
|
enum nat_manip_type_e manip_type)
|
|
{
|
|
switch (ipv4->proto)
|
|
{
|
|
#ifdef CONFIG_NET_TCP
|
|
case IP_PROTO_TCP:
|
|
return ipv4_nat_inbound_tcp(ipv4, manip_type);
|
|
#endif
|
|
|
|
#ifdef CONFIG_NET_UDP
|
|
case IP_PROTO_UDP:
|
|
return ipv4_nat_inbound_udp(ipv4, manip_type);
|
|
#endif
|
|
|
|
#ifdef CONFIG_NET_ICMP
|
|
case IP_PROTO_ICMP:
|
|
return ipv4_nat_inbound_icmp(ipv4, manip_type);
|
|
#endif
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: ipv4_nat_outbound_internal
|
|
*
|
|
* Description:
|
|
* Check if we want to perform NAT with this outbound packet before
|
|
* sending it. If so, translate the local IP/Port to external IP/Port.
|
|
*
|
|
* Input Parameters:
|
|
* dev - The device to sent the packet (to get external IP).
|
|
* ipv4 - Points to the IPv4 header to translate.
|
|
* manip_type - Whether local IP/Port is in source or destination.
|
|
*
|
|
* Returned Value:
|
|
* The corresponding NAT entry of the packet.
|
|
*
|
|
* Assumptions:
|
|
* Packet will be sent on NAT device.
|
|
*
|
|
****************************************************************************/
|
|
|
|
static FAR struct ipv4_nat_entry *
|
|
ipv4_nat_outbound_internal(FAR struct net_driver_s *dev,
|
|
FAR struct ipv4_hdr_s *ipv4,
|
|
enum nat_manip_type_e manip_type)
|
|
{
|
|
switch (ipv4->proto)
|
|
{
|
|
#ifdef CONFIG_NET_TCP
|
|
case IP_PROTO_TCP:
|
|
return ipv4_nat_outbound_tcp(dev, ipv4, manip_type);
|
|
#endif
|
|
|
|
#ifdef CONFIG_NET_UDP
|
|
case IP_PROTO_UDP:
|
|
return ipv4_nat_outbound_udp(dev, ipv4, manip_type);
|
|
#endif
|
|
|
|
#ifdef CONFIG_NET_ICMP
|
|
case IP_PROTO_ICMP:
|
|
return ipv4_nat_outbound_icmp(dev, ipv4, manip_type);
|
|
#endif
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* 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.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int ipv4_nat_enable(FAR struct net_driver_s *dev)
|
|
{
|
|
net_lock();
|
|
|
|
if (IFF_IS_NAT(dev->d_flags))
|
|
{
|
|
nwarn("WARNING: NAT was already enabled for %s!\n", dev->d_ifname);
|
|
net_unlock();
|
|
return -EEXIST;
|
|
}
|
|
|
|
IFF_SET_NAT(dev->d_flags);
|
|
|
|
net_unlock();
|
|
return OK;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* 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)
|
|
{
|
|
net_lock();
|
|
|
|
if (!IFF_IS_NAT(dev->d_flags))
|
|
{
|
|
nwarn("WARNING: NAT was not enabled for %s!\n", dev->d_ifname);
|
|
net_unlock();
|
|
return -ENODEV;
|
|
}
|
|
|
|
/* Clear entries related to dev. */
|
|
|
|
ipv4_nat_entry_clear(dev);
|
|
|
|
IFF_CLR_NAT(dev->d_flags);
|
|
|
|
net_unlock();
|
|
return OK;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* 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)
|
|
{
|
|
/* We only process packets from NAT device and targeting at the address
|
|
* assigned to the device.
|
|
*/
|
|
|
|
if (IFF_IS_NAT(dev->d_flags) &&
|
|
net_ipv4addr_hdrcmp(ipv4->destipaddr, &dev->d_ipaddr))
|
|
{
|
|
FAR struct ipv4_nat_entry *entry =
|
|
ipv4_nat_inbound_internal(ipv4, NAT_MANIP_DST);
|
|
if (!entry)
|
|
{
|
|
/* Inbound without entry is OK (e.g. towards NuttX itself), skip. */
|
|
|
|
return OK;
|
|
}
|
|
}
|
|
|
|
return OK;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* 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.
|
|
* manip_type - Whether local IP/Port is in source or destination.
|
|
*
|
|
* 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,
|
|
enum nat_manip_type_e manip_type)
|
|
{
|
|
/* We only process packets targeting at NAT device but not targeting at the
|
|
* address assigned to the device.
|
|
*/
|
|
|
|
if (IFF_IS_NAT(dev->d_flags) &&
|
|
!net_ipv4addr_hdrcmp(ipv4->srcipaddr, &dev->d_ipaddr) &&
|
|
!net_ipv4addr_hdrcmp(ipv4->destipaddr, &dev->d_ipaddr))
|
|
{
|
|
/* TODO: Skip broadcast? */
|
|
|
|
FAR struct ipv4_nat_entry *entry =
|
|
ipv4_nat_outbound_internal(dev, ipv4, manip_type);
|
|
if (manip_type == NAT_MANIP_SRC && !entry)
|
|
{
|
|
/* Outbound entry creation failed, should have entry. */
|
|
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
return OK;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* 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)
|
|
{
|
|
FAR struct ipv4_nat_entry *entry =
|
|
ipv4_nat_inbound_entry_find(protocol, ip, port, false);
|
|
|
|
return entry != NULL;
|
|
}
|
|
|
|
#endif /* CONFIG_NET_NAT && CONFIG_NET_IPv4 */
|