-/* 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.
- */
-
-static const char rcsid[] = "$Id: ares_gethostbyaddr.c,v 1.1 1998/08/13 18:06:29 ghudson Exp $";
-
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/nameser.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <netdb.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;
-
- 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;
-}