/****************************************************************************
* apps/netutils/netlib/netlib_ipv6adaptor.c
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <net/if.h>
#include <nuttx/net/ip.h>
#include "netutils/netlib.h"
#ifdef CONFIG_NET_IPv6
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: _netlib_ipv6adaptor
*
* Description:
* Given the destination address, destipaddr, return the IP address
* assigned to the network adaptor that connects the sub-net that
* includes destipaddr.
*
* NOTE: This does not account for any routing information that may
* appear in the routing table. A complete solution could involve three
* steps:
*
* 1. Call netlib_ipv6adaptor() to find the address of the network
* adaptor for the destination address.
* 2. If this fails, then look up the router address in the routing table
* that can forward to the destination address, then
* 3. Call netlib_ipv6adaptor() to find the address of the network
* adaptor for that router address.
*
* Input Parameters:
* destipaddr - The destination IPv6 address
* srcipaddr - The location to return that adaptor address that serves
* the sub-net that includes the destination address.
*
* Returned Value:
* Zero (OK) is returned on success with srcipaddr valid. A negated
* errno value is returned on any failure and in this case the srcipaddr
* is not valid.
*
****************************************************************************/
static int _netlib_ipv6adaptor(FAR const struct in6_addr *destipaddr,
FAR struct in6_addr *srcipaddr)
{
FAR struct lifreq *lifr;
struct lifconf lifc;
size_t allocsize;
size_t buflen;
int nintf;
int ret;
int sd;
int i;
/* REVISIT: Should check the routing table to see if there is a route
* for the destipaddr before finding the device that provides the sub-net.
*/
/* Find the size of the buffer we need to hold the interface descriptions */
lifc.lifc_req = NULL;
lifc.lifc_len = 0;
sd = socket(AF_INET6, NETLIB_SOCK_TYPE, 0);
if (sd < 0)
{
ret = -errno;
fprintf(stderr, "ERROR: socket() failed: %d\n", ret);
return ret;
}
ret = ioctl(sd, SIOCGLIFCONF, (unsigned long)((uintptr_t)&lifc));
if (ret < 0)
{
ret = -errno;
fprintf(stderr, "ERROR: ioctl(SIOCGLIFCONF) failed: %d\n", ret);
goto errout_with_sd;
}
/* Allocate the buffer to hold the interface descriptions */
allocsize = lifc.lifc_len;
lifr = (FAR struct lifreq *)malloc(allocsize);
if (lifr == NULL)
{
fprintf(stderr, "ERROR: Failed to allocate LIFC buffer\n");
ret = -ENOMEM;
goto errout_with_sd;
}
/* Get the interface descriptions */
lifc.lifc_req = lifr;
ret = ioctl(sd, SIOCGLIFCONF, (unsigned long)((uintptr_t)&lifc));
if (ret < 0)
{
ret = -errno;
fprintf(stderr, "ERROR: ioctl(SIOCGLIFCONF) failed: %d\n", ret);
goto errout_with_ifr;
}
/* Find an interface that supports the subnet needed by the provided
* IPv6 address. Be careful! The size of the returned buffer could
* be different if the network device configuration changed in between
* the two calls!
*/
buflen = lifc.lifc_len;
if (buflen > allocsize)
{
/* Something has changed. Limit to the original size (OR do the
* allocation and IOCTL again).
*/
buflen = allocsize;
}
nintf = buflen / sizeof(struct lifreq);
ret = -EHOSTUNREACH;
for (i = 0; i < nintf; i++)
{
FAR struct lifreq *req = &lifr[i];
FAR struct sockaddr_in6 *addr =
(FAR struct sockaddr_in6 *)&req->lifr_addr;
struct lifreq maskreq;
FAR struct sockaddr_in6 *netmask;
int status;
/* Get the network mask */
strncpy(maskreq.lifr_name, lifr->lifr_name, IFNAMSIZ);
status = ioctl(sd, SIOCGLIFNETMASK,
(unsigned long)((uintptr_t)&maskreq));
if (status < 0)
{
ret = -errno;
fprintf(stderr, "ERROR: ioctl(SIOCGLIFNETMASK) failed: %d\n",
ret);
goto errout_with_ifr;
}
netmask = (FAR struct sockaddr_in6 *)&maskreq.lifr_addr;
/* Does this device provide the sub-net? */
if (net_ipv6addr_maskcmp(addr->sin6_addr.s6_addr16,
destipaddr->s6_addr16,
netmask->sin6_addr.s6_addr16))
{
/* Yes.. return the IP address assigned to this adaptor */
net_ipv6addr_copy(srcipaddr->s6_addr16,
addr->sin6_addr.s6_addr16);
ret = OK;
break;
}
}
errout_with_ifr:
free(lifr);
errout_with_sd:
close(sd);
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: netlib_ipv6adaptor
*
* Description:
* Given the destination address, destipaddr, return the IP address
* assigned to the network adaptor that connects the sub-net that
* includes destipaddr.
*
* If routing table support is enabled, then this logic will account for
* the case where the destination address is not locally accessible. In
* this case, it will return the IP address of the network adaptor that
* provides the correct router to handle that destination address.
*
* Input Parameters:
* destipaddr - The destination IPv6 address
* srcipaddr - The location to return that adaptor address that serves
* the sub-net that includes the destination address.
*
* Returned Value:
* Zero (OK) is returned on success with srcipaddr valid. A negated
* errno value is returned on any failure and in this case the srcipaddr
* is not valid.
*
****************************************************************************/
int netlib_ipv6adaptor(FAR const struct in6_addr *destipaddr,
FAR struct in6_addr *srcipaddr)
{
int ret;
DEBUGASSERT(destipaddr != NULL && srcipaddr != NULL);
ret = _netlib_ipv6adaptor(destipaddr, srcipaddr);
#ifdef HAVE_ROUTE_PROCFS
if (ret < 0)
{
struct in6_addr router;
/* If the first adaptor look-up on the the destination IP address
* failed, then the IP address cannot be sent on any of the
* currently up network devices configured with an IPv6 address.
*
* But perhaps the destination address is on a sub-net that is
* accessible on a router that can be reached through a local
* network adaptor?
*/
ret = netlib_ipv6router(destipaddr, &router);
if (ret >= 0)
{
/* Yes... try again using the router address as the destination
* address.
*/
ret = _netlib_ipv6adaptor(&router, srcipaddr);
}
}
#endif
return ret;
}
#endif /* CONFIG_NET_IPv6 */