1 /*- 2 * Copyright (c) 1999 Brian Somers <brian@Awfulhak.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/lib/libutil/realhostname.c,v 1.6.2.6 2002/06/29 18:26:37 ume Exp $ 27 */ 28 29 #include <sys/param.h> 30 31 #include <sys/socket.h> 32 #include <netdb.h> 33 #include <netinet/in.h> 34 #include <arpa/inet.h> 35 36 #include <stdio.h> 37 #include <string.h> 38 39 #include "libutil.h" 40 41 /* wrapper for KAME-special getnameinfo() */ 42 #ifndef NI_WITHSCOPEID 43 #define NI_WITHSCOPEID 0 44 #endif 45 46 struct sockinet { 47 u_char si_len; 48 u_char si_family; 49 u_short si_port; 50 }; 51 52 int 53 realhostname(char *host, size_t hsize, const struct in_addr *ip) 54 { 55 char trimmed[MAXHOSTNAMELEN]; 56 int result; 57 struct hostent *hp; 58 59 result = HOSTNAME_INVALIDADDR; 60 hp = gethostbyaddr((char *)ip, sizeof(*ip), AF_INET); 61 62 if (hp != NULL) { 63 strlcpy(trimmed, hp->h_name, sizeof(trimmed)); 64 trimdomain(trimmed, strlen(trimmed)); 65 if (strlen(trimmed) <= hsize) { 66 char lookup[MAXHOSTNAMELEN]; 67 68 strncpy(lookup, hp->h_name, sizeof(lookup) - 1); 69 lookup[sizeof(lookup) - 1] = '\0'; 70 hp = gethostbyname(lookup); 71 if (hp == NULL) 72 result = HOSTNAME_INVALIDNAME; 73 else for (; ; hp->h_addr_list++) { 74 if (*hp->h_addr_list == NULL) { 75 result = HOSTNAME_INCORRECTNAME; 76 break; 77 } 78 if (!memcmp(*hp->h_addr_list, ip, sizeof(*ip))) { 79 strncpy(host, trimmed, hsize); 80 return HOSTNAME_FOUND; 81 } 82 } 83 } 84 } 85 86 strncpy(host, inet_ntoa(*ip), hsize); 87 88 return result; 89 } 90 91 int 92 realhostname_sa(char *host, size_t hsize, struct sockaddr *addr, int addrlen) 93 { 94 int result, error; 95 char buf[NI_MAXHOST]; 96 struct sockaddr_in sin; 97 98 result = HOSTNAME_INVALIDADDR; 99 100 #ifdef INET6 101 /* IPv4 mapped IPv6 addr consideraton, specified in rfc2373. */ 102 if (addr->sa_family == AF_INET6 && 103 addrlen == sizeof(struct sockaddr_in6) && 104 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)addr)->sin6_addr)) { 105 struct sockaddr_in6 *sin6; 106 107 sin6 = (struct sockaddr_in6 *)addr; 108 109 memset(&sin, 0, sizeof(sin)); 110 sin.sin_len = sizeof(struct sockaddr_in); 111 sin.sin_family = AF_INET; 112 sin.sin_port = sin6->sin6_port; 113 memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[12], 114 sizeof(struct in_addr)); 115 addr = (struct sockaddr *)&sin; 116 addrlen = sin.sin_len; 117 } 118 #endif 119 120 error = getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0, 121 NI_WITHSCOPEID | NI_NAMEREQD); 122 if (error == 0) { 123 struct addrinfo hints, *res, *ores; 124 struct sockaddr *sa; 125 126 memset(&hints, 0, sizeof(struct addrinfo)); 127 hints.ai_family = addr->sa_family; 128 hints.ai_flags = AI_CANONNAME | AI_PASSIVE; 129 hints.ai_socktype = SOCK_STREAM; 130 131 error = getaddrinfo(buf, NULL, &hints, &res); 132 if (error) { 133 result = HOSTNAME_INVALIDNAME; 134 goto numeric; 135 } 136 for (ores = res; ; res = res->ai_next) { 137 if (res == NULL) { 138 freeaddrinfo(ores); 139 result = HOSTNAME_INCORRECTNAME; 140 goto numeric; 141 } 142 sa = res->ai_addr; 143 if (sa == NULL) { 144 freeaddrinfo(ores); 145 result = HOSTNAME_INCORRECTNAME; 146 goto numeric; 147 } 148 if (sa->sa_len == addrlen && 149 sa->sa_family == addr->sa_family) { 150 ((struct sockinet *)sa)->si_port = ((struct sockinet *)addr)->si_port; 151 #ifdef INET6 152 /* 153 * XXX: sin6_socpe_id may not been 154 * filled by DNS 155 */ 156 if (sa->sa_family == AF_INET6 && 157 ((struct sockaddr_in6 *)sa)->sin6_scope_id == 0) 158 ((struct sockaddr_in6 *)sa)->sin6_scope_id = ((struct sockaddr_in6 *)addr)->sin6_scope_id; 159 #endif 160 if (!memcmp(sa, addr, sa->sa_len)) { 161 result = HOSTNAME_FOUND; 162 if (ores->ai_canonname == NULL) { 163 freeaddrinfo(ores); 164 goto numeric; 165 } 166 strlcpy(buf, ores->ai_canonname, 167 sizeof(buf)); 168 trimdomain(buf, hsize); 169 if (strlen(buf) > hsize && 170 addr->sa_family == AF_INET) { 171 freeaddrinfo(ores); 172 goto numeric; 173 } 174 strncpy(host, buf, hsize); 175 break; 176 } 177 } 178 } 179 freeaddrinfo(ores); 180 } else { 181 numeric: 182 if (getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0, 183 NI_NUMERICHOST|NI_WITHSCOPEID) == 0) 184 strncpy(host, buf, hsize); 185 } 186 187 return result; 188 } 189 190 191