nuttx-apps/netutils/netlib/netlib_ipv6router.c
Gregory Nutt dc5be379a9 Squashed commit of the following:
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()
2017-09-20 10:35:56 -06:00

149 lines
5.0 KiB
C

/****************************************************************************
* netutils/netlib/netlib_ipv6router.c
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdio.h>
#include <errno.h>
#include <arpa/inet.h>
#include <nuttx/net/ip.h>
#include "netutils/netlib.h"
#if defined(CONFIG_NET_IPv6) && defined(HAVE_ROUTE_PROCFS)
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: netlib_ipv6router
*
* Description:
* Given a destination address that is no on a local network, query the
* IPv6 routing table, and return the IPv6 address of the routing that
* will provide access to the correct sub-net.
*
* Input Parameters:
* destipaddr - The destination address to use in the look-up (in network
* byte order).
* router - The location to return that the IP address of the router
* (in network byte order)
*
* Returned Value:
* Zero is returned on success; a negated errno value is returned on any
* failure.
*
****************************************************************************/
int netlib_ipv6router(FAR const struct in6_addr *destipaddr,
FAR struct in6_addr *router)
{
struct netlib_ipv6_route_s route;
FILE *stream;
uint16_t hdest[8];
ssize_t nbytes;
int ret = -ENOENT;
/* Open the routing table file */
stream = netlib_open_ipv6route();
if (stream == NULL)
{
return -errno;
}
/* Convert the destination IP address to host byte order for the
* comparison.
*/
hdest[0] = ntohs(destipaddr->s6_addr16[0]);
hdest[1] = ntohs(destipaddr->s6_addr16[1]);
hdest[2] = ntohs(destipaddr->s6_addr16[2]);
hdest[3] = ntohs(destipaddr->s6_addr16[3]);
hdest[4] = ntohs(destipaddr->s6_addr16[4]);
hdest[5] = ntohs(destipaddr->s6_addr16[5]);
hdest[6] = ntohs(destipaddr->s6_addr16[6]);
hdest[7] = ntohs(destipaddr->s6_addr16[7]);
/* Find the routing table entry that provides the router for this sub-net. */
for (; ; )
{
/* Read the route (in host byte order) */
nbytes = netlib_read_ipv6route(stream, &route);
if (nbytes == 0)
{
/* End of file with no match */
break;
}
else if (nbytes < 0)
{
/* Read error */
ret = (int)nbytes;
break;
}
/* Compare the prefix and the destination address under the mask */
if (net_ipv6addr_maskcmp(route.prefix, hdest, route.netmask))
{
/* Found it! Return the router address in network byte order */
router->s6_addr16[0] = htons(route.router[0]);
router->s6_addr16[1] = htons(route.router[1]);
router->s6_addr16[2] = htons(route.router[2]);
router->s6_addr16[3] = htons(route.router[3]);
router->s6_addr16[4] = htons(route.router[4]);
router->s6_addr16[5] = htons(route.router[5]);
router->s6_addr16[6] = htons(route.router[6]);
router->s6_addr16[7] = htons(route.router[7]);
ret = OK;
break;
}
}
netlib_close_ipv6route(stream);
return ret;
}
#endif /* CONFIG_NET_IPv6 && HAVE_ROUTE_PROCFS */