dc5be379a9
apps/netutils/netlib: netlib_ipv[4|6]adaptor() will now use the new routing table interfaces if they are available: If the desination IP address does not correspond to the network served by any device, then the address of the router that should get us to the correct sub-net is is determined. Then the network adaptor that can communicate with the that router has the IP address that will returned.
apps/netutils/netlib: Add new utilities netlib_ipv[4|6]router() that can be used to determine the IP address of a router that would be used some some destination IP address that is not locally accessible.
apps/netutils/netlib: Add helpers for reading the routing table: netlib_read_ipv4route() and netlib_read_ipv6route()
135 lines
4.3 KiB
C
135 lines
4.3 KiB
C
/****************************************************************************
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* netutils/netlib/netlib_ipv4router.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 <stdio.h>
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#include <errno.h>
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#include <arpa/inet.h>
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#include <nuttx/net/ip.h>
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#include "netutils/netlib.h"
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#if defined(CONFIG_NET_IPv4) && defined(HAVE_ROUTE_PROCFS)
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: netlib_ipv4router
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*
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* Description:
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* Given a destination address that is no on a local network, query the
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* IPv4 routing table, and return the IPv4 address of the routing that
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* will provide access to the correct sub-net.
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*
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* Input Parameters:
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* destipaddr - The destination address to use in the look-up (in network
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* byte order).
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* router - The location to return that the IP address of the router
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* (in network byte order)
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*
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* Returned Value:
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* Zero is returned on success; a negated errno value is returned on any
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* failure.
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*
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****************************************************************************/
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int netlib_ipv4router(FAR const struct in_addr *destipaddr,
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FAR struct in_addr *router)
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{
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struct netlib_ipv4_route_s route;
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FILE *stream;
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in_addr_t hdest;
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ssize_t nbytes;
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int ret = -ENOENT;
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/* Open the routing table file */
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stream = netlib_open_ipv4route();
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if (stream == NULL)
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{
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return -errno;
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}
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/* Convert the destination IP address to host byte order for the
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* comparison.
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*/
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hdest = ntohl(destipaddr->s_addr);
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/* Find the routing table entry that provides the router for this sub-net. */
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for (; ; )
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{
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/* Read the route (in host byte order) */
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nbytes = netlib_read_ipv4route(stream, &route);
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if (nbytes == 0)
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{
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/* End of file with no match */
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break;
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}
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else if (nbytes < 0)
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{
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/* Read error */
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ret = (int)nbytes;
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break;
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}
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/* Compare the prefix and the destination address under the mask */
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if (net_ipv4addr_maskcmp(route.prefix, hdest, route.netmask))
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{
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/* Found it! Return the router address in network byte order */
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router->s_addr = htonl(route.router);
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ret = OK;
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break;
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}
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}
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netlib_close_ipv4route(stream);
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return ret;
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}
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#endif /* CONFIG_NET_IPv4 && HAVE_ROUTE_PROCFS */
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