/****************************************************************************
* libs/libc/netdb/lib_dnsforeach.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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <arpa/inet.h>
#include <nuttx/net/dns.h>
#include "netdb/lib_dns.h"
#ifdef CONFIG_NETDB_DNSCLIENT
/****************************************************************************
* Private Functions
****************************************************************************/
#ifdef CONFIG_NETDB_RESOLVCONF
static FAR char *skip_spaces(FAR char *ptr)
{
while (isspace(*ptr)) ptr++;
return ptr;
}
static FAR char *find_spaces(FAR char *ptr)
{
while (*ptr && !isspace(*ptr)) ptr++;
return ptr;
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: dns_foreach_nameserver
*
* Description:
* Traverse each nameserver entry in the resolv.conf file and perform
* the provided callback.
*
****************************************************************************/
#ifdef CONFIG_NETDB_RESOLVCONF
int dns_foreach_nameserver(dns_callback_t callback, FAR void *arg)
{
union dns_addr_u u;
FAR FILE *stream;
char line[DNS_MAX_LINE];
FAR char *addrstr;
FAR char *ptr;
unsigned int count;
uint16_t port;
int keylen;
int ret;
/* Open the resolver configuration file */
stream = fopen(CONFIG_NETDB_RESOLVCONF_PATH, "r");
if (stream == NULL)
{
ret = -get_errno();
nerr("ERROR: Failed to open %s: %d\n",
CONFIG_NETDB_RESOLVCONF_PATH, ret);
DEBUGASSERT(ret < 0);
return ret;
}
dns_lock();
keylen = strlen(NETDB_DNS_KEYWORD);
while (fgets(line, DNS_MAX_LINE, stream) != NULL)
{
ptr = skip_spaces(line);
if (strncmp(ptr, NETDB_DNS_KEYWORD, keylen) == 0)
{
/* Skip over the 'nameserver' keyword */
ptr = find_spaces(ptr);
addrstr = skip_spaces(ptr);
if (*addrstr == '\0')
{
nerr("ERROR: Missing address in %s record\n",
CONFIG_NETDB_RESOLVCONF_PATH);
continue;
}
/* Make sure that the address string is NUL terminated and
* not followed by garbage.
*/
ptr = find_spaces(addrstr);
*ptr = '\0';
/* Convert the address string to a binary representation. */
port = HTONS(DNS_DEFAULT_PORT);
#ifdef CONFIG_NETDB_RESOLVCONF_NONSTDPORT
/* The OpenBSD version supports a [host]:port syntax. When a
* non-standard port is specified the host address must be
* enclosed in square brackets. For example:
*
* nameserver [10.0.0.1]:5353
* nameserver [::1]:5353
*/
if (*addrstr == '[')
{
/* Make sure that there is a right bracket */
ptr = strchr(addrstr, ']');
if (ptr == NULL)
{
nerr("ERROR: Missing right bracket after %s\n", line);
continue;
}
/* Replace the right bracket with a NULL terminator */
addrstr++;
*ptr++ = '\0';
/* Get the port number following the right bracket */
if (*ptr++ == ':')
{
FAR char *portstr;
int tmp;
/* Isolate the port string */
portstr = ptr;
ptr = find_spaces(ptr);
*ptr = '\0';
/* Get the port number */
tmp = atoi(portstr);
if (tmp != 0)
{
port = HTONS(tmp);
}
}
}
#endif /* CONFIG_NETDB_RESOLVCONF_NONSTDPORT */
#ifdef CONFIG_NET_IPv4
/* Try to convert the IPv4 address */
ret = inet_pton(AF_INET, addrstr, &u.ipv4.sin_addr);
/* The inet_pton() function returns 1 if the conversion succeeds */
if (ret == 1)
{
u.ipv4.sin_family = AF_INET;
u.ipv4.sin_port = port;
dns_breaklock(&count);
ret = callback(arg, (FAR struct sockaddr *)&u.ipv4,
sizeof(struct sockaddr_in));
dns_restorelock(count);
}
else
#endif
#ifdef CONFIG_NET_IPv6
{
/* Try to convert the IPv6 address */
ret = inet_pton(AF_INET6, addrstr, &u.ipv6.sin6_addr);
/* The inet_pton() function returns 1 if the conversion
* succeeds.
*/
if (ret == 1)
{
u.ipv6.sin6_family = AF_INET6;
u.ipv6.sin6_port = port;
dns_breaklock(&count);
ret = callback(arg, (FAR struct sockaddr *)&u.ipv6,
sizeof(struct sockaddr_in6));
dns_restorelock(count);
}
else
#endif
{
nerr("ERROR: Unrecognized address: %s\n", addrstr);
ret = OK;
}
#ifdef CONFIG_NET_IPv6
}
#endif
if (ret != OK)
{
break;
}
}
}
dns_unlock();
fclose(stream);
return ret;
}
#else /* CONFIG_NETDB_RESOLVCONF */
int dns_foreach_nameserver(dns_callback_t callback, FAR void *arg)
{
FAR struct sockaddr *addr;
unsigned int count;
int ret = OK;
int i;
dns_lock();
for (i = 0; i < g_dns_nservers; i++)
{
#ifdef CONFIG_NET_IPv4
/* Check for an IPv4 address */
if (g_dns_servers[i].addr.sa_family == AF_INET)
{
struct sockaddr_in copy;
/* Operate on copy of server address, in case it changes. */
memcpy(©, &g_dns_servers[i].ipv4, sizeof(struct sockaddr_in));
addr = (FAR struct sockaddr *)©
/* Perform the callback */
dns_breaklock(&count);
ret = callback(arg, addr, sizeof(struct sockaddr_in));
dns_restorelock(count);
}
else
#endif
#ifdef CONFIG_NET_IPv6
/* Check for an IPv6 address */
if (g_dns_servers[i].addr.sa_family == AF_INET6)
{
struct sockaddr_in6 copy;
/* Operate on copy of server address, in case it changes. */
memcpy(©, &g_dns_servers[i].ipv6, sizeof(struct sockaddr_in6));
addr = (FAR struct sockaddr *)©
/* Perform the callback */
dns_breaklock(&count);
ret = callback(arg, addr, sizeof(struct sockaddr_in6));
dns_restorelock(count);
}
else
#endif
{
nerr("ERROR: Unsupported family: %d\n",
g_dns_servers[i].addr.sa_family);
ret = -ENOSYS;
}
if (ret != OK)
{
break;
}
}
dns_unlock();
return ret;
}
#endif /* CONFIG_NETDB_RESOLVCONF */
#endif /* CONFIG_NETDB_DNSCLIENT */