getnameinfo_verified.c revision 178825 
1/*
2 * Copyright (c) 1999 - 2002 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifdef HAVE_CONFIG_H
35#include <config.h>
36RCSID("$Id: getnameinfo_verified.c 14773 2005-04-12 11:29:18Z lha $");
37#endif
38
39#include "roken.h"
40
41/*
42 * Try to obtain a verified name for the address in `sa, salen' (much
43 * similar to getnameinfo).
44 * Verified in this context means that forwards and backwards lookups
45 * in DNS are consistent.  If that fails, return an error if the
46 * NI_NAMEREQD flag is set or return the numeric address as a string.
47 */
48
49int ROKEN_LIB_FUNCTION
50getnameinfo_verified(const struct sockaddr *sa, socklen_t salen,
51		     char *host, size_t hostlen,
52		     char *serv, size_t servlen,
53		     int flags)
54{
55    int ret;
56    struct addrinfo *ai, *a;
57    char servbuf[NI_MAXSERV];
58    struct addrinfo hints;
59
60    if (host == NULL)
61	return EAI_NONAME;
62
63    if (serv == NULL) {
64	serv = servbuf;
65	servlen = sizeof(servbuf);
66    }
67
68    ret = getnameinfo (sa, salen, host, hostlen, serv, servlen,
69		       flags | NI_NUMERICSERV);
70    if (ret)
71	goto fail;
72
73    memset (&hints, 0, sizeof(hints));
74    hints.ai_socktype = SOCK_STREAM;
75    ret = getaddrinfo (host, serv, &hints, &ai);
76    if (ret)
77	goto fail;
78    for (a = ai; a != NULL; a = a->ai_next) {
79	if (a->ai_addrlen == salen
80	    && memcmp (a->ai_addr, sa, salen) == 0) {
81	    freeaddrinfo (ai);
82	    return 0;
83	}
84    }
85    freeaddrinfo (ai);
86 fail:
87    if (flags & NI_NAMEREQD)
88	return EAI_NONAME;
89    ret = getnameinfo (sa, salen, host, hostlen, serv, servlen,
90		       flags | NI_NUMERICSERV | NI_NUMERICHOST);
91    return ret;
92}
93