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 * $DragonFly: src/lib/libutil/realhostname.c,v 1.2 2003/06/17 04:26:52 dillon Exp $ 28 */ 29 30 #include <sys/param.h> 31 32 #include <sys/socket.h> 33 #include <netdb.h> 34 #include <netinet/in.h> 35 #include <arpa/inet.h> 36 37 #include <stdio.h> 38 #include <string.h> 39 40 #include "libutil.h" 41 42 /* wrapper for KAME-special getnameinfo() */ 43 #ifndef NI_WITHSCOPEID 44 #define NI_WITHSCOPEID 0 45 #endif 46 47 struct sockinet { 48 u_char si_len; 49 u_char si_family; 50 u_short si_port; 51 }; 52 53 int 54 realhostname(char *host, size_t hsize, const struct in_addr *ip) 55 { 56 char trimmed[MAXHOSTNAMELEN]; 57 int result; 58 struct hostent *hp; 59 60 result = HOSTNAME_INVALIDADDR; 61 hp = gethostbyaddr(ip, sizeof(*ip), AF_INET); 62 63 if (hp != NULL) { 64 strlcpy(trimmed, hp->h_name, sizeof(trimmed)); 65 trimdomain(trimmed, strlen(trimmed)); 66 if (strlen(trimmed) <= hsize) { 67 char lookup[MAXHOSTNAMELEN]; 68 69 strncpy(lookup, hp->h_name, sizeof(lookup) - 1); 70 lookup[sizeof(lookup) - 1] = '\0'; 71 hp = gethostbyname(lookup); 72 if (hp == NULL) 73 result = HOSTNAME_INVALIDNAME; 74 else for (; ; hp->h_addr_list++) { 75 if (*hp->h_addr_list == NULL) { 76 result = HOSTNAME_INCORRECTNAME; 77 break; 78 } 79 if (!memcmp(*hp->h_addr_list, ip, sizeof(*ip))) { 80 strncpy(host, trimmed, hsize); 81 return HOSTNAME_FOUND; 82 } 83 } 84 } 85 } 86 87 strncpy(host, inet_ntoa(*ip), hsize); 88 89 return result; 90 } 91 92 int 93 realhostname_sa(char *host, size_t hsize, struct sockaddr *addr, int addrlen) 94 { 95 int result, error; 96 char buf[NI_MAXHOST]; 97 struct sockaddr_in sin; 98 99 result = HOSTNAME_INVALIDADDR; 100 101 #ifdef INET6 102 /* IPv4 mapped IPv6 addr consideraton, specified in rfc2373. */ 103 if (addr->sa_family == AF_INET6 && 104 addrlen == sizeof(struct sockaddr_in6) && 105 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)addr)->sin6_addr)) { 106 struct sockaddr_in6 *sin6; 107 108 sin6 = (struct sockaddr_in6 *)addr; 109 110 memset(&sin, 0, sizeof(sin)); 111 sin.sin_len = sizeof(struct sockaddr_in); 112 sin.sin_family = AF_INET; 113 sin.sin_port = sin6->sin6_port; 114 memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[12], 115 sizeof(struct in_addr)); 116 addr = (struct sockaddr *)&sin; 117 addrlen = sin.sin_len; 118 } 119 #endif 120 121 error = getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0, 122 NI_WITHSCOPEID | NI_NAMEREQD); 123 if (error == 0) { 124 struct addrinfo hints, *res, *ores; 125 struct sockaddr *sa; 126 127 memset(&hints, 0, sizeof(struct addrinfo)); 128 hints.ai_family = addr->sa_family; 129 hints.ai_flags = AI_CANONNAME | AI_PASSIVE; 130 hints.ai_socktype = SOCK_STREAM; 131 132 error = getaddrinfo(buf, NULL, &hints, &res); 133 if (error) { 134 result = HOSTNAME_INVALIDNAME; 135 goto numeric; 136 } 137 for (ores = res; ; res = res->ai_next) { 138 if (res == NULL) { 139 freeaddrinfo(ores); 140 result = HOSTNAME_INCORRECTNAME; 141 goto numeric; 142 } 143 sa = res->ai_addr; 144 if (sa == NULL) { 145 freeaddrinfo(ores); 146 result = HOSTNAME_INCORRECTNAME; 147 goto numeric; 148 } 149 if (sa->sa_len == addrlen && 150 sa->sa_family == addr->sa_family) { 151 ((struct sockinet *)sa)->si_port = ((struct sockinet *)addr)->si_port; 152 #ifdef INET6 153 /* 154 * XXX: sin6_socpe_id may not been 155 * filled by DNS 156 */ 157 if (sa->sa_family == AF_INET6 && 158 ((struct sockaddr_in6 *)sa)->sin6_scope_id == 0) 159 ((struct sockaddr_in6 *)sa)->sin6_scope_id = ((struct sockaddr_in6 *)addr)->sin6_scope_id; 160 #endif 161 if (!memcmp(sa, addr, sa->sa_len)) { 162 result = HOSTNAME_FOUND; 163 if (ores->ai_canonname == NULL) { 164 freeaddrinfo(ores); 165 goto numeric; 166 } 167 strlcpy(buf, ores->ai_canonname, 168 sizeof(buf)); 169 trimdomain(buf, hsize); 170 if (strlen(buf) > hsize && 171 addr->sa_family == AF_INET) { 172 freeaddrinfo(ores); 173 goto numeric; 174 } 175 strncpy(host, buf, hsize); 176 break; 177 } 178 } 179 } 180 freeaddrinfo(ores); 181 } else { 182 numeric: 183 if (getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0, 184 NI_NUMERICHOST|NI_WITHSCOPEID) == 0) 185 strncpy(host, buf, hsize); 186 } 187 188 return result; 189 } 190 191 192