424 lines
13 KiB
C
424 lines
13 KiB
C
/****************************************************************************
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* libc/netdb/lib_gethostbyaddrr.c
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*
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* Copyright (C) 2015 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
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* 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/types.h>
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#include <stdio.h>
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#include <string.h>
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#include <netdb.h>
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#include <errno.h>
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#include <arpa/inet.h>
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#include <nuttx/net/loopback.h>
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#include "lib_internal.h"
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#include "netdb/lib_netdb.h"
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#ifdef CONFIG_NETDB_HOSTFILE
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: lib_lo_ipv4match
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*
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* Description:
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* Check if the address is the reserved IPv4 address for the local
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* loopback device.
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*
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* Input Parameters:
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* addr - The address of the host to find.
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* len - The length of the address
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* type - The type of the address
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*
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* Returned Value:
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* True if the address is the IPv4 local loopback address.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_LOOPBACK
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static bool lib_lo_ipv4match(FAR const void *addr, socklen_t len, int type)
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{
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FAR struct in_addr *ipv4addr;
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if (type == AF_INET && len >= sizeof(struct in_addr))
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{
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ipv4addr = (FAR struct in_addr *)addr;
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return net_ipv4addr_maskcmp(ipv4addr->sin_addr.s_addr,
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g_lo_ipv4addr->s_addr,
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g_lo_ipv4addr->s_addr);
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}
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return false;
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}
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#endif
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/****************************************************************************
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* Name: lib_lo_ipv6match
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*
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* Description:
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* Check if the address is the reserved IPv6 address for the local
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* loopback device.
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*
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* Input Parameters:
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* addr - The address of the host to find.
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* len - The length of the address
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* type - The type of the address
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*
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* Returned Value:
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* True if the address is the IPv4 local loopback address.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_LOOPBACK
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static bool lib_lo_ipv6match(FAR const void *addr, socklen_t len, int type)
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{
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FAR struct in_addr6 *ipv6addr;
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if (type == AF_INE6T && len >= sizeof(struct in_addr6))
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{
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ipv6addr = (FAR struct in_addr6 *)addr;
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return net_ipv6addr_cmp(ipv6addr->sin6_addr.s6_addr16, g_lo_ipv6addr);
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}
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return false;
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}
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#endif
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/****************************************************************************
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* Name: lib_localhost
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*
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* Description:
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* Check if the address is the reserved address for the local loopback
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* device.
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*
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* Input Parameters:
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* addr - The address of the host to find.
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* len - The length of the address
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* type - The type of the address
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* host - Caller provided location to return the host data.
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* buf - Caller provided buffer to hold string data associated with the
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* host data.
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* buflen - The size of the caller-provided buffer
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* h_errnop - There h_errno value returned in the event of a failure.
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*
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* Returned Value:
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* Zero (OK) is returned on success, -1 (ERROR) is returned on a failure
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* with the returned h_errno value provided the reason for the failure.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_LOOPBACK
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static int lib_localhost(FAR const void *addr, socklen_t len, int type,
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FAR struct hostent *host, FAR char *buf,
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size_t buflen, int *h_errnop)
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{
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FAR struct hostent_info_s *info;
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socklen_t addrlen;
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FAR const uint8_t *src;
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FAR char *dest;
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bool match;
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int herrnocode;
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int namelen;
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if (lib_lo_ipv4match(addr, len, type))
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{
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/* Setup to transfer the IPv4 address */
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addrlen = sizeof(struct in_addr);
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src = (FAR uint8_t *)&g_lo_ipv4addr;
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host->h_addrtype = AF_INET;
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}
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else if (lib_lo_ipv4match(addr, len, type))
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{
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/* Setup to transfer the IPv6 address */
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addrlen = sizeof(struct in6_addr);
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src = (FAR uint8_t *)&g_lo_ipv6addr;
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host->h_addrtype = AF_INET6;
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}
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else
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{
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/* Return 1 meaning that we have no errors but no match either */
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return 1;
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}
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/* Make sure that space remains to hold the hostent structure and
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* the IP address.
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*/
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if (buflen <= (sizeof(struct hostent_info_s) + addrlen))
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{
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return -ERANGE;
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}
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info = (FAR struct hostent_info_s *)buf;
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dest = info->hi_data;
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buflen -= (sizeof(struct hostent_info_s) - 1);
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memset(host, 0, sizeof(struct hostent));
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memset(info, 0, sizeof(struct hostent_info_s));
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memcpy(dest, src, addrlen);
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info->hi_addrlist[0] = dest;
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host->h_addr_list = info->hi_addrlist;
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host->h_length = addrlen;
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dest += addrlen;
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buflen -= addrlen;
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/* And copy localhost host name */
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namelen = strlen(g_lo_hostname);
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if (addrlen + namelen + 1 > buflen)
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{
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herrnocode = ERANGE;
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goto errorout_with_herrnocode;
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}
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strncpy(dest, g_lo_hostname, buflen);
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return 0;
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}
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return 1;
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errorout_with_herrnocode:
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if (h_errnop)
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{
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*h_errnop = herrnocode;
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}
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return ERROR;
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}
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#endif
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/****************************************************************************
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* Name: lib_hostfile_lookup
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*
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* Description:
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* Try to look-up the host name from the network host file
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*
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* Input Parameters:
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* addr - The address of the host to find.
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* len - The length of the address
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* type - The type of the address
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* host - Caller provided location to return the host data.
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* buf - Caller provided buffer to hold string data associated with the
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* host data.
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* buflen - The size of the caller-provided buffer
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* h_errnop - There h_errno value returned in the event of a failure.
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*
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* Returned Value:
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* Zero (OK) is returned on success, -1 (ERROR) is returned on a failure
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* with the returned h_errno value provided the reason for the failure.
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*
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****************************************************************************/
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int lib_hostfile_lookup(FAR const void *addr, socklen_t len, int type,
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FAR struct hostent *host, FAR char *buf,
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size_t buflen, int *h_errnop)
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{
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FAR FILE *stream;
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int herrnocode;
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int nread;
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/* Search the hosts file for a match */
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stream = fopen(CONFIG_NETDB_HOSTCONF_PATH, "r");
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if (stream == NULL)
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{
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int errcode = errno;
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ndbg("ERROR: Failed to open the hosts file %s: %d\n",
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CONFIG_NETDB_HOSTCONF_PATH, errcode);
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UNUSED(errcode);
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herrnocode = NO_RECOVERY;
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goto errorout_with_herrnocode;
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}
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/* Loop reading entries from the hosts file until a match is found or
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* until we hit the end-of-file.
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*/
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do
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{
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/* Read the next entry from the hosts file */
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nread = lib_parse_hostfile(stream, host, buf, buflen);
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if (nread < 0)
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{
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/* Possible errors:
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* ERANGE - Buffer not big enough
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* ESPIPE - End of file (or possibly a read error).
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* EAGAIN - Error parsing the line (E.g., missing hostname)
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*/
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if (nread == -ESPIPE)
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{
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nread = 0;
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}
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else if (nread != -EAGAIN)
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{
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herrnocode = NO_RECOVERY;
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goto errorout_with_stream;
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}
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}
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else if (nread > 0 && len == host->h_length && type == host->h_addrtype)
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{
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/* We successfully read the entry and the type and size of the
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* address is good. Now compare the addresses:
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*/
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FAR char *hostaddr = host->h_addr;
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if (hostaddr != NULL)
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{
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nvdbg("Comparing addresses...\n");
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if (memcmp(addr, hostaddr, len) == 0)
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{
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/* We have a match */
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fclose(stream);
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return OK;
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}
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}
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}
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}
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while (nread != 0);
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/* We get here when the end of the hosts file is encountered without
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* finding the hostname.
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*/
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herrnocode = HOST_NOT_FOUND;
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errorout_with_stream:
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fclose(stream);
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errorout_with_herrnocode:
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if (h_errnop)
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{
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*h_errnop = herrnocode;
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}
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return ERROR;
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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: gethostbyaddr_r
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*
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* Description:
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* The gethostbyaddr_r() function returns a structure of type hostent for
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* the given host address addr of length len and address type type. Valid
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* address types are AF_INET and AF_INET6. The host address argument is a
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* pointer to a struct of a type depending on the address type, for example
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* a struct in_addr * for address type AF_INET.
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*
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* gethostbyaddr_r() is *not* POSIX but is similar to a Glibc extension and is
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* used internally by NuttX to implement the POSIX gethostbyaddr().
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*
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* Input Parameters:
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* addr - The address of the host to find.
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* len - The length of the address
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* type - The type of the address
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* host - Caller provided location to return the host data.
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* buf - Caller provided buffer to hold string data associated with the
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* host data.
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* buflen - The size of the caller-provided buffer
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* h_errnop - There h_errno value returned in the event of a failure.
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*
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* Returned Value:
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* Zero (OK) is returned on success, -1 (ERROR) is returned on a failure
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* with the returned h_errno value provided the reason for the failure.
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*
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****************************************************************************/
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int gethostbyaddr_r(FAR const void *addr, socklen_t len, int type,
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FAR struct hostent *host, FAR char *buf,
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size_t buflen, int *h_errnop)
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{
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FAR FILE *stream;
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int herrnocode;
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int nread;
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DEBUGASSERT(addr != NULL && host != NULL && buf != NULL);
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DEBUGASSERT(type == AF_INET || type == AF_INET6);
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/* Make sure that the h_errno has a non-error code */
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if (h_errnop)
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{
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*h_errnop = 0;
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}
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#ifdef CONFIG_NET_LOOPBACK
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/* Check for the local loopback address */
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if (lib_localhost(addr, len, type, host, buf, buflen, h_errnop) == 0)
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{
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/* Yes.. we are done */
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return OK;
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}
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#endif
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/* TODO:
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*
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* 1. Look in the DNS cache to see if we have the address mapping already
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* in place. If not,
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* 2. Perform a reverse DNS lookup. And if that fails as well, then
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* finally
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* 3. Search the hosts file for a match.
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*/
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/* Search the hosts file for a match */
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return lib_hostfile_lookup(addr, len, type, host, buf, buflen, h_errnop);
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}
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#endif /* CONFIG_NETDB_HOSTFILE */
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