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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 <sys/types.h>
#ifdef WIN32
#include "nameser.h"
#else
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/nameser.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ares.h"
#include "ares_private.h"
struct addr_query {
/* Arguments passed to ares_gethostbyaddr() */
ares_channel channel;
struct in_addr addr;
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(struct in_addr *addr, 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 || addrlen != sizeof(struct in_addr))
{
callback(arg, ARES_ENOTIMP, NULL);
return;
}
aquery = malloc(sizeof(struct addr_query));
if (!aquery)
{
callback(arg, ARES_ENOMEM, NULL);
return;
}
aquery->channel = channel;
memcpy(&aquery->addr, addr, sizeof(aquery->addr));
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[64];
int a1, a2, a3, a4, status;
struct hostent *host;
unsigned long addr;
for (p = aquery->remaining_lookups; *p; p++)
{
switch (*p)
{
case 'b':
addr = ntohl(aquery->addr.s_addr);
a1 = addr >> 24;
a2 = (addr >> 16) & 0xff;
a3 = (addr >> 8) & 0xff;
a4 = 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);
return;
case 'f':
status = file_lookup(&aquery->addr, &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)
{
status = ares_parse_ptr_reply(abuf, alen, &aquery->addr,
sizeof(struct in_addr), AF_INET, &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(struct in_addr *addr, struct hostent **host)
{
FILE *fp;
int status;
#ifdef WIN32
char PATH_HOSTS[MAX_PATH];
if (IsNT) {
GetSystemDirectory(PATH_HOSTS, MAX_PATH);
strcat(PATH_HOSTS, PATH_HOSTS_NT);
} else {
GetWindowsDirectory(PATH_HOSTS, MAX_PATH);
strcat(PATH_HOSTS, PATH_HOSTS_9X);
}
#endif
fp = fopen(PATH_HOSTS, "r");
if (!fp)
return ARES_ENOTFOUND;
while ((status = ares__get_hostent(fp, host)) == ARES_SUCCESS)
{
if (memcmp((*host)->h_addr, addr, sizeof(struct in_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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