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> 36 RCSID("$Id: getnameinfo_verified.c,v 1.6 2002/09/05 01:36:27 assar Exp $"); 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 49 int 50 getnameinfo_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