1 /* $NetBSD: getnameinfo_verified.c,v 1.1.1.1 2011/04/13 18:15:41 elric Exp $ */ 2 3 /* 4 * Copyright (c) 1999 - 2002 Kungliga Tekniska Högskolan 5 * (Royal Institute of Technology, Stockholm, Sweden). 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * 3. Neither the name of the Institute nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <config.h> 37 38 #include <krb5/roken.h> 39 40 /* 41 * Try to obtain a verified name for the address in `sa, salen' (much 42 * similar to getnameinfo). 43 * Verified in this context means that forwards and backwards lookups 44 * in DNS are consistent. If that fails, return an error if the 45 * NI_NAMEREQD flag is set or return the numeric address as a string. 46 */ 47 48 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL 49 getnameinfo_verified(const struct sockaddr *sa, socklen_t salen, 50 char *host, size_t hostlen, 51 char *serv, size_t servlen, 52 int flags) 53 { 54 int ret; 55 struct addrinfo *ai, *a; 56 char servbuf[NI_MAXSERV]; 57 struct addrinfo hints; 58 void *saaddr; 59 size_t sasize; 60 61 if (host == NULL) 62 return EAI_NONAME; 63 64 if (serv == NULL) { 65 serv = servbuf; 66 servlen = sizeof(servbuf); 67 } 68 69 ret = getnameinfo (sa, salen, host, hostlen, serv, servlen, 70 flags | NI_NUMERICSERV); 71 if (ret) 72 goto fail; 73 74 memset (&hints, 0, sizeof(hints)); 75 hints.ai_socktype = SOCK_STREAM; 76 ret = getaddrinfo (host, serv, &hints, &ai); 77 if (ret) 78 goto fail; 79 80 saaddr = socket_get_address(sa); 81 sasize = socket_addr_size(sa); 82 for (a = ai; a != NULL; a = a->ai_next) { 83 if (sasize == socket_addr_size(a->ai_addr) && 84 memcmp(saaddr, socket_get_address(a->ai_addr), sasize) == 0) { 85 freeaddrinfo (ai); 86 return 0; 87 } 88 } 89 freeaddrinfo (ai); 90 fail: 91 if (flags & NI_NAMEREQD) 92 return EAI_NONAME; 93 ret = getnameinfo (sa, salen, host, hostlen, serv, servlen, 94 flags | NI_NUMERICSERV | NI_NUMERICHOST); 95 return ret; 96 } 97