+++ /dev/null
-/* 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_gethostbyname.c,v 1.7 1999/10/23 19:28:13 danw Exp $";
-
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <arpa/nameser.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <ctype.h>
-#include <netdb.h>
-#include "ares.h"
-#include "ares_private.h"
-
-struct host_query {
- /* Arguments passed to ares_gethostbyname() */
- ares_channel channel;
- char *name;
- ares_host_callback callback;
- void *arg;
-
- const char *remaining_lookups;
-};
-
-static void next_lookup(struct host_query *hquery);
-static void host_callback(void *arg, int status, unsigned char *abuf,
- int alen);
-static void end_hquery(struct host_query *hquery, int status,
- struct hostent *host);
-static int fake_hostent(const char *name, ares_host_callback callback,
- void *arg);
-static int file_lookup(const char *name, struct hostent **host);
-static void sort_addresses(struct hostent *host, struct apattern *sortlist,
- int nsort);
-static int get_address_index(struct in_addr *addr, struct apattern *sortlist,
- int nsort);
-
-void ares_gethostbyname(ares_channel channel, const char *name, int family,
- ares_host_callback callback, void *arg)
-{
- struct host_query *hquery;
-
- /* Right now we only know how to look up Internet addresses. */
- if (family != AF_INET)
- {
- callback(arg, ARES_ENOTIMP, NULL);
- return;
- }
-
- if (fake_hostent(name, callback, arg))
- return;
-
- /* Allocate and fill in the host query structure. */
- hquery = malloc(sizeof(struct host_query));
- if (!hquery)
- {
- callback(arg, ARES_ENOMEM, NULL);
- return;
- }
- hquery->channel = channel;
- hquery->name = strdup(name);
- if (!hquery->name)
- {
- free(hquery);
- callback(arg, ARES_ENOMEM, NULL);
- return;
- }
- hquery->callback = callback;
- hquery->arg = arg;
- hquery->remaining_lookups = channel->lookups;
-
- /* Start performing lookups according to channel->lookups. */
- next_lookup(hquery);
-}
-
-static void next_lookup(struct host_query *hquery)
-{
- int status;
- const char *p;
- struct hostent *host;
-
- for (p = hquery->remaining_lookups; *p; p++)
- {
- switch (*p)
- {
- case 'b':
- /* DNS lookup */
- hquery->remaining_lookups = p + 1;
- ares_search(hquery->channel, hquery->name, C_IN, T_A, host_callback,
- hquery);
- return;
-
- case 'f':
- /* Host file lookup */
- status = file_lookup(hquery->name, &host);
- if (status != ARES_ENOTFOUND)
- {
- end_hquery(hquery, status, host);
- return;
- }
- break;
- }
- }
- end_hquery(hquery, ARES_ENOTFOUND, NULL);
-}
-
-static void host_callback(void *arg, int status, unsigned char *abuf, int alen)
-{
- struct host_query *hquery = (struct host_query *) arg;
- ares_channel channel = hquery->channel;
- struct hostent *host;
-
- if (status == ARES_SUCCESS)
- {
- status = ares_parse_a_reply(abuf, alen, &host);
- if (host && channel->nsort)
- sort_addresses(host, channel->sortlist, channel->nsort);
- end_hquery(hquery, status, host);
- }
- else if (status == ARES_EDESTRUCTION)
- end_hquery(hquery, status, NULL);
- else
- next_lookup(hquery);
-}
-
-static void end_hquery(struct host_query *hquery, int status,
- struct hostent *host)
-{
- hquery->callback(hquery->arg, status, host);
- if (host)
- ares_free_hostent(host);
- free(hquery->name);
- free(hquery);
-}
-
-/* If the name looks like an IP address, fake up a host entry, end the
- * query immediately, and return true. Otherwise return false.
- */
-static int fake_hostent(const char *name, ares_host_callback callback,
- void *arg)
-{
- struct in_addr addr;
- struct hostent hostent;
- const char *p;
- char *aliases[1] = { NULL };
- char *addrs[2];
-
- /* It only looks like an IP address if it's all numbers and dots. */
- for (p = name; *p; p++)
- {
- if (!isdigit((unsigned char)*p) && *p != '.')
- return 0;
- }
-
- /* It also only looks like an IP address if it's non-zero-length and
- * doesn't end with a dot.
- */
- if (p == name || *(p - 1) == '.')
- return 0;
-
- /* It looks like an IP address. Figure out what IP address it is. */
- addr.s_addr = inet_addr(name);
- if (addr.s_addr == INADDR_NONE)
- {
- callback(arg, ARES_EBADNAME, NULL);
- return 1;
- }
-
- /* Duplicate the name, to avoid a constness violation. */
- hostent.h_name = strdup(name);
- if (!hostent.h_name)
- {
- callback(arg, ARES_ENOMEM, NULL);
- return 1;
- }
-
- /* Fill in the rest of the host structure and terminate the query. */
- addrs[0] = (char *) &addr;
- addrs[1] = NULL;
- hostent.h_aliases = aliases;
- hostent.h_addrtype = AF_INET;
- hostent.h_length = sizeof(struct in_addr);
- hostent.h_addr_list = addrs;
- callback(arg, ARES_SUCCESS, &hostent);
-
- free(hostent.h_name);
- return 1;
-}
-
-static int file_lookup(const char *name, struct hostent **host)
-{
- FILE *fp;
- char **alias;
- int status;
-
- fp = fopen(PATH_HOSTS, "r");
- if (!fp)
- return ARES_ENOTFOUND;
-
- while ((status = ares__get_hostent(fp, 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;
-}
-
-static void sort_addresses(struct hostent *host, 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(struct in_addr *addr, struct apattern *sortlist,
- int nsort)
-{
- int i;
-
- for (i = 0; i < nsort; i++)
- {
- if ((addr->s_addr & sortlist[i].mask.s_addr) == sortlist[i].addr.s_addr)
- break;
- }
- return i;
-}
projects / 1ts-debian.git / blobdiff