/**************************************************************************** * apps/netutils/netlib/netlib_ipv4adaptor.c * * Copyright (C) 2017 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include #include #include #include "netutils/netlib.h" #ifdef CONFIG_NET_IPv4 /**************************************************************************** * Priver Functions ****************************************************************************/ /**************************************************************************** * Name: _netlib_ipv4adaptor * * 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_ipv4adaptor() 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_ipv4adaptor() to find the address of the network * adaptor for that router address. * * Input Parameters: * destipaddr - The destination IPv4 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_ipv4adaptor(in_addr_t destipaddr, FAR in_addr_t *srcipaddr) { FAR struct ifreq *ifr; struct ifconf ifc; 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 */ ifc.ifc_req = NULL; ifc.ifc_len = 0; sd = socket(AF_INET, NETLIB_SOCK_TYPE, 0); if (sd < 0) { ret = -errno; fprintf(stderr, "ERROR: socket() failed: %d\n", ret); return ret; } ret = ioctl(sd, SIOCGIFCONF, (unsigned long)((uintptr_t)&ifc)); if (ret < 0) { ret = -errno; fprintf(stderr, "ERROR: ioctl(SIOCGIFCONF) failed: %d\n", ret); goto errout_with_sd; } /* Allocate the buffer to hold the interface descriptions */ allocsize = ifc.ifc_len; ifr = (FAR struct ifreq *)malloc(allocsize); if (ifr == NULL) { fprintf(stderr, "ERROR: Failed to allocate IFC buffer\n"); ret = -ENOMEM; goto errout_with_sd; } /* Get the interface descriptions */ ifc.ifc_req = ifr; ret = ioctl(sd, SIOCGIFCONF, (unsigned long)((uintptr_t)&ifc)); if (ret < 0) { ret = -errno; fprintf(stderr, "ERROR: ioctl(SIOCGIFCONF) failed: %d\n", ret); goto errout_with_ifr; } /* Find an interface that supports the subnet needed by the provided * IPv4 address. Be careful! The size of the returned buffer could * be different if the network device configuration changed in between * the two calls! */ buflen = ifc.ifc_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 ifreq); ret = -EHOSTUNREACH; for (i = 0; i < nintf; i++) { FAR struct ifreq *req = &ifr[i]; FAR struct sockaddr_in *addr = (FAR struct sockaddr_in *)&req->ifr_addr; struct ifreq maskreq; FAR struct sockaddr_in *netmask; /* Get the network mask */ strncpy(maskreq.ifr_name, ifr->ifr_name, IFNAMSIZ); ret = ioctl(sd, SIOCGIFNETMASK, (unsigned long)((uintptr_t)&maskreq)); if (ret < 0) { ret = -errno; fprintf(stderr, "ERROR: ioctl(SIOCGIFNETMASK) failed: %d\n", ret); goto errout_with_ifr; } netmask = (FAR struct sockaddr_in *)&maskreq.ifr_addr; /* Does this device provide the sub-net? */ if (net_ipv4addr_maskcmp(addr->sin_addr.s_addr, destipaddr, netmask->sin_addr.s_addr)) { /* Yes.. return the IP address assigned to this adaptor */ *srcipaddr = addr->sin_addr.s_addr; ret = OK; break; } } errout_with_ifr: free(ifr); errout_with_sd: close(sd); return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: netlib_ipv4adaptor * * 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 IPv4 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_ipv4adaptor(in_addr_t destipaddr, FAR in_addr_t *srcipaddr) { int ret; DEBUGASSERT(srcipaddr != NULL); ret = _netlib_ipv4adaptor(destipaddr, srcipaddr); #ifdef HAVE_ROUTE_PROCFS if (ret < 0) { struct in_addr router; struct in_addr destinaddr; /* 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 IPv4 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? */ destinaddr.s_addr = destipaddr; ret = netlib_ipv4router(&destinaddr, &router); if (ret >= 0) { /* Yes... try again using the router address as the destination * address. */ ret = _netlib_ipv4adaptor(router.s_addr, srcipaddr); } } #endif return ret; } #endif /* CONFIG_NET_IPv4 */