1/*
2 * Copyright (c) 1999 - 2002 Kungliga Tekniska Högskolan
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#include <config.h>
35
36#include "roken.h"
37
38/*
39 * Try to obtain a verified name for the address in `sa, salen' (much
40 * similar to getnameinfo).
41 * Verified in this context means that forwards and backwards lookups
42 * in DNS are consistent.  If that fails, return an error if the
43 * NI_NAMEREQD flag is set or return the numeric address as a string.
44 */
45
46ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
47getnameinfo_verified(const struct sockaddr *sa, socklen_t salen,
48		     char *host, socklen_t hostlen,
49		     char *serv, socklen_t servlen,
50		     int flags)
51{
52    int ret;
53    struct addrinfo *ai, *a;
54    char servbuf[NI_MAXSERV];
55    struct addrinfo hints;
56    void *saaddr;
57    size_t sasize;
58
59    if (host == NULL)
60	return EAI_NONAME;
61
62    if (serv == NULL) {
63	serv = servbuf;
64	servlen = sizeof(servbuf);
65    }
66
67    ret = getnameinfo (sa, salen, host, hostlen, serv, servlen,
68		       flags | NI_NUMERICSERV);
69    if (ret)
70	goto fail;
71
72    memset (&hints, 0, sizeof(hints));
73    hints.ai_socktype = SOCK_STREAM;
74    ret = getaddrinfo (host, serv, &hints, &ai);
75    if (ret)
76	goto fail;
77
78    saaddr = socket_get_address(sa);
79    sasize = socket_addr_size(sa);
80    for (a = ai; a != NULL; a = a->ai_next) {
81	if (sasize == socket_addr_size(a->ai_addr) &&
82	    memcmp(saaddr, socket_get_address(a->ai_addr), sasize) == 0) {
83	    freeaddrinfo (ai);
84	    return 0;
85	}
86    }
87    freeaddrinfo (ai);
88 fail:
89    if (flags & NI_NAMEREQD)
90	return EAI_NONAME;
91    ret = getnameinfo (sa, salen, host, hostlen, serv, servlen,
92		       flags | NI_NUMERICSERV | NI_NUMERICHOST);
93    return ret;
94}
95