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/* 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 "setup.h"
#include <sys/types.h>
#if defined(WIN32) && !defined(WATT32)
#include "nameser.h"
#else
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/nameser.h>
#ifdef HAVE_ARPA_NAMESER_COMPAT_H
#include <arpa/nameser_compat.h>
#endif
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ares.h"
#include "ares_private.h"
#include "inet_net_pton.h"
#ifdef WATT32
#undef WIN32
#endif
struct addr_query {
/* Arguments passed to ares_gethostbyaddr() */
ares_channel channel;
union ares_addr addr;
int family;
ares_host_callback callback;
void *arg;
const char *remaining_lookups;
};
static void next_lookup(struct addr_query *aquery);
static void addr_callback(void *arg, int status, unsigned char *abuf,
int alen);
static void end_aquery(struct addr_query *aquery, int status,
struct hostent *host);
static int file_lookup(union ares_addr *addr, int family, struct hostent **host);
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, NULL);
return;
}
if ((family == AF_INET && addrlen != sizeof(struct in_addr)) ||
(family == AF_INET6 && addrlen != sizeof(struct in6_addr)))
{
callback(arg, ARES_ENOTIMP, NULL);
return;
}
aquery = malloc(sizeof(struct addr_query));
if (!aquery)
{
callback(arg, ARES_ENOMEM, NULL);
return;
}
aquery->channel = channel;
if (family == AF_INET)
memcpy(&aquery->addr.addr4, addr, sizeof(struct in_addr));
else
memcpy(&aquery->addr.addr6, addr, sizeof(struct in6_addr));
aquery->family = family;
aquery->callback = callback;
aquery->arg = arg;
aquery->remaining_lookups = channel->lookups;
next_lookup(aquery);
}
static void next_lookup(struct addr_query *aquery)
{
const char *p;
char name[128];
int a1, a2, a3, a4, status;
struct hostent *host;
unsigned long addr;
for (p = aquery->remaining_lookups; *p; p++)
{
switch (*p)
{
case 'b':
if (aquery->family == AF_INET)
{
addr = ntohl(aquery->addr.addr4.s_addr);
a1 = (int)((addr >> 24) & 0xff);
a2 = (int)((addr >> 16) & 0xff);
a3 = (int)((addr >> 8) & 0xff);
a4 = (int)(addr & 0xff);
sprintf(name, "%d.%d.%d.%d.in-addr.arpa", a4, a3, a2, a1);
aquery->remaining_lookups = p + 1;
ares_query(aquery->channel, name, C_IN, T_PTR, addr_callback,
aquery);
}
else
{
unsigned char *bytes;
bytes = (unsigned char *)&aquery->addr.addr6.s6_addr;
sprintf(name, "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa",
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,
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);
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, aquery->family, &host);
if (status != ARES_ENOTFOUND)
{
end_aquery(aquery, status, host);
return;
}
break;
}
}
end_aquery(aquery, ARES_ENOTFOUND, NULL);
}
static void addr_callback(void *arg, int status, unsigned char *abuf, int alen)
{
struct addr_query *aquery = (struct addr_query *) arg;
struct hostent *host;
if (status == ARES_SUCCESS)
{
if (aquery->family == AF_INET)
status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addr4,
sizeof(struct in_addr), AF_INET, &host);
else
status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addr6,
sizeof(struct in6_addr), AF_INET6, &host);
end_aquery(aquery, status, host);
}
else if (status == ARES_EDESTRUCTION)
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, host);
if (host)
ares_free_hostent(host);
free(aquery);
}
static int file_lookup(union ares_addr *addr, int family, struct hostent **host)
{
FILE *fp;
int status;
#ifdef WIN32
char PATH_HOSTS[MAX_PATH];
if (IS_NT()) {
char tmp[MAX_PATH];
HKEY hkeyHosts;
if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ, &hkeyHosts)
== ERROR_SUCCESS)
{
DWORD dwLength = MAX_PATH;
RegQueryValueEx(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp,
&dwLength);
ExpandEnvironmentStrings(tmp, PATH_HOSTS, MAX_PATH);
RegCloseKey(hkeyHosts);
}
}
else
GetWindowsDirectory(PATH_HOSTS, MAX_PATH);
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)
return ARES_ENOTFOUND;
while ((status = ares__get_hostent(fp, family, host)) == ARES_SUCCESS)
{
if (family != (*host)->h_addrtype)
{
ares_free_hostent(*host);
continue;
}
if (family == AF_INET)
{
if (memcmp((*host)->h_addr, &addr->addr4, sizeof(struct in_addr)) == 0)
break;
}
else if (family == AF_INET6)
{
if (memcmp((*host)->h_addr, &addr->addr6, sizeof(struct in6_addr)) == 0)
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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