280 lines
8.8 KiB
C
280 lines
8.8 KiB
C
/****************************************************************************
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* netutils/netlib/netlib_ipv4adaptor.c
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*
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* Copyright (C) 2017 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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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 <sys/socket.h>
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#include <sys/ioctl.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <net/if.h>
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#include <nuttx/net/ip.h>
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#include "netutils/netlib.h"
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#ifdef CONFIG_NET_IPv4
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/****************************************************************************
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* Priver Functions
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****************************************************************************/
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/****************************************************************************
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* Name: _netlib_ipv4adaptor
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*
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* Description:
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* Given the destination address, destipaddr, return the IP address
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* assigned to the network adaptor that connects the sub-net that
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* includes destipaddr.
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*
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* NOTE: This does not account for any routing information that may
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* appear in the routing table. A complete solution could involve three
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* steps:
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*
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* 1. Call netlib_ipv4adaptor() to find the address of the network
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* adaptor for the destination address.
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* 2. If this fails, then look up the router address in the routing table
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* that can forward to the destination address, then
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* 3. Call netlib_ipv4adaptor() to find the address of the network
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* adaptor for that router address.
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*
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* Input Parameters:
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* destipaddr - The destination IPv4 address
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* srcipaddr - The location to return that adaptor address that serves
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* the sub-net that includes the destination address.
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*
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* Returned Value:
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* Zero (OK) is returned on success with srcipaddr valid. A negated
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* errno value is returned on any failure and in this case the srcipaddr
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* is not valid.
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*
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****************************************************************************/
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static int _netlib_ipv4adaptor(in_addr_t destipaddr, FAR in_addr_t *srcipaddr)
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{
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FAR struct ifreq *ifr;
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struct ifconf ifc;
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size_t allocsize;
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size_t buflen;
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int nintf;
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int ret;
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int sd;
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int i;
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/* REVISIT: Should check the routing table to see if there is a route
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* for the destipaddr before finding the device that provides the sub-net.
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*/
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/* Find the size of the buffer we need to hold the interface descriptions */
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ifc.ifc_req = NULL;
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ifc.ifc_len = 0;
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sd = socket(AF_INET, NETLIB_SOCK_TYPE, 0);
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if (sd < 0)
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{
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ret = -errno;
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fprintf(stderr, "ERROR: socket() failed: %d\n", ret);
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return ret;
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}
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ret = ioctl(sd, SIOCGIFCONF, (unsigned long)((uintptr_t)&ifc));
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if (ret < 0)
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{
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ret = -errno;
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fprintf(stderr, "ERROR: ioctl(SIOCGIFCONF) failed: %d\n", ret);
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goto errout_with_sd;
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}
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/* Allocate the buffer to hold the interface descriptions */
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allocsize = ifc.ifc_len;
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ifr = (FAR struct ifreq *)malloc(allocsize);
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if (ifr == NULL)
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{
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fprintf(stderr, "ERROR: Failed to allocate IFC buffer\n");
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ret = -ENOMEM;
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goto errout_with_sd;
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}
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/* Get the interface descriptions */
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ifc.ifc_req = ifr;
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ret = ioctl(sd, SIOCGIFCONF, (unsigned long)((uintptr_t)&ifc));
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if (ret < 0)
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{
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ret = -errno;
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fprintf(stderr, "ERROR: ioctl(SIOCGIFCONF) failed: %d\n", ret);
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goto errout_with_ifr;
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}
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/* Find an interface that supports the subnet needed by the provided
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* IPv4 address. Be careful! The size of the returned buffer could
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* be different if the network device configuration changed in between
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* the two calls!
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*/
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buflen = ifc.ifc_len;
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if (buflen > allocsize)
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{
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/* Something has changed. Limit to the original size (OR do the
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* allocation and IOCTL again).
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*/
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buflen = allocsize;
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}
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nintf = buflen / sizeof(struct ifreq);
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ret = -EHOSTUNREACH;
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for (i = 0; i < nintf; i++)
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{
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FAR struct ifreq *req = &ifr[i];
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FAR struct sockaddr_in *addr =
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(FAR struct sockaddr_in *)&req->ifr_addr;
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struct ifreq maskreq;
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FAR struct sockaddr_in *netmask;
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/* Get the network mask */
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strncpy(maskreq.ifr_name, ifr->ifr_name, IFNAMSIZ);
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ret = ioctl(sd, SIOCGIFNETMASK, (unsigned long)((uintptr_t)&maskreq));
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if (ret < 0)
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{
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ret = -errno;
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fprintf(stderr, "ERROR: ioctl(SIOCGIFNETMASK) failed: %d\n",
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ret);
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goto errout_with_ifr;
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}
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netmask = (FAR struct sockaddr_in *)&maskreq.ifr_addr;
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/* Does this device provide the sub-net? */
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if (net_ipv4addr_maskcmp(addr->sin_addr.s_addr, destipaddr,
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netmask->sin_addr.s_addr))
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{
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/* Yes.. return the IP address assigned to this adaptor */
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*srcipaddr = addr->sin_addr.s_addr;
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ret = OK;
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break;
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}
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}
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errout_with_ifr:
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free(ifr);
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errout_with_sd:
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close(sd);
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: netlib_ipv4adaptor
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*
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* Description:
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* Given the destination address, destipaddr, return the IP address
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* assigned to the network adaptor that connects the sub-net that
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* includes destipaddr.
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*
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* If routing table support is enabled, then this logic will account for
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* the case where the destination address is not locally accessible. In
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* this case, it will return the IP address of the network adaptor that
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* provides the correct router to handle that destination address.
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*
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* Input Parameters:
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* destipaddr - The destination IPv4 address
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* srcipaddr - The location to return that adaptor address that serves
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* the sub-net that includes the destination address.
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*
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* Returned Value:
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* Zero (OK) is returned on success with srcipaddr valid. A negated
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* errno value is returned on any failure and in this case the srcipaddr
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* is not valid.
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*
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****************************************************************************/
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int netlib_ipv4adaptor(in_addr_t destipaddr, FAR in_addr_t *srcipaddr)
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{
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int ret;
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DEBUGASSERT(srcipaddr != NULL);
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ret = _netlib_ipv4adaptor(destipaddr, srcipaddr);
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#ifdef HAVE_ROUTE_PROCFS
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if (ret < 0)
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{
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struct in_addr router;
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struct in_addr destinaddr;
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/* If the first adaptor look-up on the the destination IP address
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* failed, then the IP address cannot be sent on any of the currently
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* up network devices configured with an IPv4 address.
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*
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* But perhaps the destination address is on a sub-net that is
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* accessible on a router that can be reached through a local network
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* adaptor?
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*/
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destinaddr.s_addr = destipaddr;
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ret = netlib_ipv4router(&destinaddr, &router);
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if (ret >= 0)
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{
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/* Yes... try again using the router address as the destination
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* address.
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*/
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ret = _netlib_ipv4adaptor(router.s_addr, srcipaddr);
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}
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}
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#endif
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return ret;
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}
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#endif /* CONFIG_NET_IPv4 */
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