current/deps/cares/src/ares_gethostbyaddr.c
/* Copyright 1998 by the Massachusetts Institute of Technology.
*
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting
* documentation, and that the name of M.I.T. not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is"
* without express or implied warranty.
*/
#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
#ifdef HAVE_ARPA_NAMESER_H
# include <arpa/nameser.h>
#else
# include "nameser.h"
#endif
#ifdef HAVE_ARPA_NAMESER_COMPAT_H
# include <arpa/nameser_compat.h>
#endif
#include "ares.h"
#include "ares_inet_net_pton.h"
#include "ares_platform.h"
#include "ares_private.h"
#ifdef WATT32
#undef WIN32
#endif
struct addr_query {
/* Arguments passed to ares_gethostbyaddr() */
ares_channel channel;
struct ares_addr addr;
ares_host_callback callback;
void *arg;
const char *remaining_lookups;
int timeouts;
};
static void next_lookup(struct addr_query *aquery);
static void addr_callback(void *arg, int status, int timeouts,
unsigned char *abuf, int alen);
static void end_aquery(struct addr_query *aquery, int status,
struct hostent *host);
static int file_lookup(struct ares_addr *addr, struct hostent **host);
static void ptr_rr_name(char *name, const struct ares_addr *addr);
void ares_gethostbyaddr(ares_channel channel, const void *addr, int addrlen,
int family, ares_host_callback callback, void *arg)
{
struct addr_query *aquery;
if (family != AF_INET && family != AF_INET6)
{
callback(arg, ARES_ENOTIMP, 0, NULL);
return;
}
if ((family == AF_INET && addrlen != sizeof(aquery->addr.addrV4)) ||
(family == AF_INET6 && addrlen != sizeof(aquery->addr.addrV6)))
{
callback(arg, ARES_ENOTIMP, 0, NULL);
return;
}
aquery = ares_malloc(sizeof(struct addr_query));
if (!aquery)
{
callback(arg, ARES_ENOMEM, 0, NULL);
return;
}
aquery->channel = channel;
if (family == AF_INET)
memcpy(&aquery->addr.addrV4, addr, sizeof(aquery->addr.addrV4));
else
memcpy(&aquery->addr.addrV6, addr, sizeof(aquery->addr.addrV6));
aquery->addr.family = family;
aquery->callback = callback;
aquery->arg = arg;
aquery->remaining_lookups = channel->lookups;
aquery->timeouts = 0;
next_lookup(aquery);
}
static void next_lookup(struct addr_query *aquery)
{
const char *p;
char name[128];
int status;
struct hostent *host;
for (p = aquery->remaining_lookups; *p; p++)
{
switch (*p)
{
case 'b':
ptr_rr_name(name, &aquery->addr);
aquery->remaining_lookups = p + 1;
ares_query(aquery->channel, name, C_IN, T_PTR, addr_callback,
aquery);
return;
case 'f':
status = file_lookup(&aquery->addr, &host);
/* this status check below previously checked for !ARES_ENOTFOUND,
but we should not assume that this single error code is the one
that can occur, as that is in fact no longer the case */
if (status == ARES_SUCCESS)
{
end_aquery(aquery, status, host);
return;
}
break;
}
}
end_aquery(aquery, ARES_ENOTFOUND, NULL);
}
static void addr_callback(void *arg, int status, int timeouts,
unsigned char *abuf, int alen)
{
struct addr_query *aquery = (struct addr_query *) arg;
struct hostent *host;
size_t addrlen;
aquery->timeouts += timeouts;
if (status == ARES_SUCCESS)
{
if (aquery->addr.family == AF_INET)
{
addrlen = sizeof(aquery->addr.addrV4);
status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addrV4,
(int)addrlen, AF_INET, &host);
}
else
{
addrlen = sizeof(aquery->addr.addrV6);
status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addrV6,
(int)addrlen, AF_INET6, &host);
}
end_aquery(aquery, status, host);
}
else if (status == ARES_EDESTRUCTION || status == ARES_ECANCELLED)
end_aquery(aquery, status, NULL);
else
next_lookup(aquery);
}
static void end_aquery(struct addr_query *aquery, int status,
struct hostent *host)
{
aquery->callback(aquery->arg, status, aquery->timeouts, host);
if (host)
ares_free_hostent(host);
ares_free(aquery);
}
static int file_lookup(struct ares_addr *addr, struct hostent **host)
{
FILE *fp;
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)
extern const char *_w32_GetHostsFile (void);
const char *PATH_HOSTS = _w32_GetHostsFile();
if (!PATH_HOSTS)
return ARES_ENOTFOUND;
#endif
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, addr->family, host)) == ARES_SUCCESS)
{
if (addr->family != (*host)->h_addrtype)
{
ares_free_hostent(*host);
continue;
}
if (addr->family == AF_INET)
{
if (memcmp((*host)->h_addr, &addr->addrV4,
sizeof(addr->addrV4)) == 0)
break;
}
else if (addr->family == AF_INET6)
{
if (memcmp((*host)->h_addr, &addr->addrV6,
sizeof(addr->addrV6)) == 0)
break;
}
ares_free_hostent(*host);
}
fclose(fp);
if (status == ARES_EOF)
status = ARES_ENOTFOUND;
if (status != ARES_SUCCESS)
*host = NULL;
return status;
}
static void ptr_rr_name(char *name, const struct ares_addr *addr)
{
if (addr->family == AF_INET)
{
unsigned long laddr = ntohl(addr->addrV4.s_addr);
unsigned long a1 = (laddr >> 24UL) & 0xFFUL;
unsigned long a2 = (laddr >> 16UL) & 0xFFUL;
unsigned long a3 = (laddr >> 8UL) & 0xFFUL;
unsigned long a4 = laddr & 0xFFUL;
sprintf(name, "%lu.%lu.%lu.%lu.in-addr.arpa", a4, a3, a2, a1);
}
else
{
unsigned char *bytes = (unsigned char *)&addr->addrV6;
/* There are too many arguments to do this in one line using
* minimally C89-compliant compilers */
sprintf(name,
"%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.",
bytes[15]&0xf, bytes[15] >> 4, bytes[14]&0xf, bytes[14] >> 4,
bytes[13]&0xf, bytes[13] >> 4, bytes[12]&0xf, bytes[12] >> 4,
bytes[11]&0xf, bytes[11] >> 4, bytes[10]&0xf, bytes[10] >> 4,
bytes[9]&0xf, bytes[9] >> 4, bytes[8]&0xf, bytes[8] >> 4);
sprintf(name+strlen(name),
"%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa",
bytes[7]&0xf, bytes[7] >> 4, bytes[6]&0xf, bytes[6] >> 4,
bytes[5]&0xf, bytes[5] >> 4, bytes[4]&0xf, bytes[4] >> 4,
bytes[3]&0xf, bytes[3] >> 4, bytes[2]&0xf, bytes[2] >> 4,
bytes[1]&0xf, bytes[1] >> 4, bytes[0]&0xf, bytes[0] >> 4);
}
}