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/* MIT License
*
* Copyright (c) 1998, 2011, 2013 Massachusetts Institute of Technology
* Copyright (c) The c-ares project and its contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* SPDX-License-Identifier: MIT
*/
#include "ares_setup.h"
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
# include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
# include <arpa/inet.h>
#endif
#include "ares_nameser.h"
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#include "ares.h"
#include "ares_inet_net_pton.h"
#include "bitncmp.h"
#include "ares_platform.h"
#include "ares_nowarn.h"
#include "ares_private.h"
static void sort_addresses(struct hostent *host,
const struct apattern *sortlist, int nsort);
static void sort6_addresses(struct hostent *host,
const struct apattern *sortlist, int nsort);
static int get_address_index(const struct in_addr *addr,
const struct apattern *sortlist, int nsort);
static int get6_address_index(const struct ares_in6_addr *addr,
const struct apattern *sortlist, int nsort);
struct host_query {
ares_host_callback callback;
void *arg;
ares_channel channel;
};
static void ares_gethostbyname_callback(void *arg, int status, int timeouts,
struct ares_addrinfo *result)
{
struct hostent *hostent = NULL;
struct host_query *ghbn_arg = arg;
if (status == ARES_SUCCESS)
{
status = ares__addrinfo2hostent(result, AF_UNSPEC, &hostent);
}
/* addrinfo2hostent will only return ENODATA if there are no addresses _and_
* no cname/aliases. However, gethostbyname will return ENODATA even if there
* is cname/alias data */
if (status == ARES_SUCCESS && hostent &&
(!hostent->h_addr_list || !hostent->h_addr_list[0]))
{
status = ARES_ENODATA;
}
if (status == ARES_SUCCESS && ghbn_arg->channel->nsort && hostent)
{
if (hostent->h_addrtype == AF_INET6)
sort6_addresses(hostent, ghbn_arg->channel->sortlist,
ghbn_arg->channel->nsort);
if (hostent->h_addrtype == AF_INET)
sort_addresses(hostent, ghbn_arg->channel->sortlist,
ghbn_arg->channel->nsort);
}
ghbn_arg->callback(ghbn_arg->arg, status, timeouts, hostent);
ares_freeaddrinfo(result);
ares_free(ghbn_arg);
ares_free_hostent(hostent);
}
void ares_gethostbyname(ares_channel channel, const char *name, int family,
ares_host_callback callback, void *arg)
{
const struct ares_addrinfo_hints hints = { ARES_AI_CANONNAME, family, 0, 0 };
struct host_query *ghbn_arg;
if (!callback)
return;
ghbn_arg = ares_malloc(sizeof(*ghbn_arg));
if (!ghbn_arg)
{
callback(arg, ARES_ENOMEM, 0, NULL);
return;
}
ghbn_arg->callback=callback;
ghbn_arg->arg=arg;
ghbn_arg->channel=channel;
ares_getaddrinfo(channel, name, NULL, &hints, ares_gethostbyname_callback,
ghbn_arg);
}
static void sort_addresses(struct hostent *host,
const struct apattern *sortlist, int nsort)
{
struct in_addr a1, a2;
int i1, i2, ind1, ind2;
/* This is a simple insertion sort, not optimized at all. i1 walks
* through the address list, with the loop invariant that everything
* to the left of i1 is sorted. In the loop body, the value at i1 is moved
* back through the list (via i2) until it is in sorted order.
*/
for (i1 = 0; host->h_addr_list[i1]; i1++)
{
memcpy(&a1, host->h_addr_list[i1], sizeof(struct in_addr));
ind1 = get_address_index(&a1, sortlist, nsort);
for (i2 = i1 - 1; i2 >= 0; i2--)
{
memcpy(&a2, host->h_addr_list[i2], sizeof(struct in_addr));
ind2 = get_address_index(&a2, sortlist, nsort);
if (ind2 <= ind1)
break;
memcpy(host->h_addr_list[i2 + 1], &a2, sizeof(struct in_addr));
}
memcpy(host->h_addr_list[i2 + 1], &a1, sizeof(struct in_addr));
}
}
/* Find the first entry in sortlist which matches addr. Return nsort
* if none of them match.
*/
static int get_address_index(const struct in_addr *addr,
const struct apattern *sortlist,
int nsort)
{
int i;
for (i = 0; i < nsort; i++)
{
if (sortlist[i].family != AF_INET)
continue;
if (sortlist[i].type == PATTERN_MASK)
{
if ((addr->s_addr & sortlist[i].mask.addr4.s_addr)
== sortlist[i].addrV4.s_addr)
break;
}
else
{
if (!ares__bitncmp(&addr->s_addr, &sortlist[i].addrV4.s_addr,
sortlist[i].mask.bits))
break;
}
}
return i;
}
static void sort6_addresses(struct hostent *host,
const struct apattern *sortlist, int nsort)
{
struct ares_in6_addr a1, a2;
int i1, i2, ind1, ind2;
/* This is a simple insertion sort, not optimized at all. i1 walks
* through the address list, with the loop invariant that everything
* to the left of i1 is sorted. In the loop body, the value at i1 is moved
* back through the list (via i2) until it is in sorted order.
*/
for (i1 = 0; host->h_addr_list[i1]; i1++)
{
memcpy(&a1, host->h_addr_list[i1], sizeof(struct ares_in6_addr));
ind1 = get6_address_index(&a1, sortlist, nsort);
for (i2 = i1 - 1; i2 >= 0; i2--)
{
memcpy(&a2, host->h_addr_list[i2], sizeof(struct ares_in6_addr));
ind2 = get6_address_index(&a2, sortlist, nsort);
if (ind2 <= ind1)
break;
memcpy(host->h_addr_list[i2 + 1], &a2, sizeof(struct ares_in6_addr));
}
memcpy(host->h_addr_list[i2 + 1], &a1, sizeof(struct ares_in6_addr));
}
}
/* Find the first entry in sortlist which matches addr. Return nsort
* if none of them match.
*/
static int get6_address_index(const struct ares_in6_addr *addr,
const struct apattern *sortlist,
int nsort)
{
int i;
for (i = 0; i < nsort; i++)
{
if (sortlist[i].family != AF_INET6)
continue;
if (!ares__bitncmp(addr, &sortlist[i].addrV6, sortlist[i].mask.bits))
break;
}
return i;
}
static int file_lookup(const char *name, int family, struct hostent **host);
/* I really have no idea why this is exposed as a public function, but since
* it is, we can't kill this legacy function. */
int ares_gethostbyname_file(ares_channel channel, const char *name,
int family, struct hostent **host)
{
int result;
/* We only take the channel to ensure that ares_init() been called. */
if(channel == NULL)
{
/* Anything will do, really. This seems fine, and is consistent with
other error cases. */
*host = NULL;
return ARES_ENOTFOUND;
}
/* Just chain to the internal implementation we use here; it's exactly
* what we want.
*/
result = file_lookup(name, family, host);
if(result != ARES_SUCCESS)
{
/* We guarantee a NULL hostent on failure. */
*host = NULL;
}
return result;
}
static int file_lookup(const char *name, int family, struct hostent **host)
{
FILE *fp;
char **alias;
int status;
int error;
#ifdef WIN32
char PATH_HOSTS[MAX_PATH];
win_platform platform;
PATH_HOSTS[0] = '\0';
platform = ares__getplatform();
if (platform == WIN_NT) {
char tmp[MAX_PATH];
HKEY hkeyHosts;
if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ,
&hkeyHosts) == ERROR_SUCCESS)
{
DWORD dwLength = MAX_PATH;
RegQueryValueExA(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp,
&dwLength);
ExpandEnvironmentStringsA(tmp, PATH_HOSTS, MAX_PATH);
RegCloseKey(hkeyHosts);
}
}
else if (platform == WIN_9X)
GetWindowsDirectoryA(PATH_HOSTS, MAX_PATH);
else
return ARES_ENOTFOUND;
strcat(PATH_HOSTS, WIN_PATH_HOSTS);
#elif defined(WATT32)
const char *PATH_HOSTS = _w32_GetHostsFile();
if (!PATH_HOSTS)
return ARES_ENOTFOUND;
#endif
/* Per RFC 7686, reject queries for ".onion" domain names with NXDOMAIN. */
if (ares__is_onion_domain(name))
return ARES_ENOTFOUND;
fp = fopen(PATH_HOSTS, "r");
if (!fp)
{
error = ERRNO;
switch(error)
{
case ENOENT:
case ESRCH:
return ARES_ENOTFOUND;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n",
PATH_HOSTS));
*host = NULL;
return ARES_EFILE;
}
}
while ((status = ares__get_hostent(fp, family, host)) == ARES_SUCCESS)
{
if (strcasecmp((*host)->h_name, name) == 0)
break;
for (alias = (*host)->h_aliases; *alias; alias++)
{
if (strcasecmp(*alias, name) == 0)
break;
}
if (*alias)
break;
ares_free_hostent(*host);
}
fclose(fp);
if (status == ARES_EOF)
status = ARES_ENOTFOUND;
if (status != ARES_SUCCESS)
*host = NULL;
return status;
}
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