realhostname.c revision 74260
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: head/lib/libutil/realhostname.c 74260 2001-03-14 20:50:52Z brian $ 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 46struct sockinet { 47 u_char si_len; 48 u_char si_family; 49 u_short si_port; 50}; 51 52int 53realhostname(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 91int 92realhostname_sa(char *host, size_t hsize, struct sockaddr *addr, int addrlen) 93{ 94 int result, error; 95 char buf[NI_MAXHOST]; 96 97 result = HOSTNAME_INVALIDADDR; 98 99 error = getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0, 0); 100 if (error == 0) { 101 struct addrinfo hints, *res, *ores; 102 struct sockaddr *sa; 103 104 memset(&hints, 0, sizeof(struct addrinfo)); 105 hints.ai_family = 106 (addr->sa_family == AF_INET) ? AF_INET : AF_UNSPEC; 107 hints.ai_flags = AI_CANONNAME; 108 109 error = getaddrinfo(buf, NULL, &hints, &res); 110 if (error) { 111 result = HOSTNAME_INVALIDNAME; 112 goto numeric; 113 } else for (ores = res; ; res = res->ai_next) { 114 if (res == NULL) { 115 freeaddrinfo(ores); 116 result = HOSTNAME_INCORRECTNAME; 117 goto numeric; 118 } 119 sa = res->ai_addr; 120 if (sa == NULL) { 121 freeaddrinfo(ores); 122 result = HOSTNAME_INCORRECTNAME; 123 goto numeric; 124 } 125 if (sa->sa_len == addrlen && 126 sa->sa_family == addr->sa_family) { 127 u_int16_t port; 128 129 port = ((struct sockinet *)addr)->si_port; 130 ((struct sockinet *)addr)->si_port = 0; 131 if (!memcmp(sa, addr, sa->sa_len)) { 132 result = HOSTNAME_FOUND; 133 ((struct sockinet *)addr)->si_port = 134 port; 135 if (ores->ai_canonname == 0) { 136 freeaddrinfo(ores); 137 goto numeric; 138 } 139 strlcpy(buf, ores->ai_canonname, 140 sizeof(buf)); 141 trimdomain(buf, hsize); 142 if (strlen(buf) > hsize && 143 addr->sa_family == AF_INET) { 144 freeaddrinfo(ores); 145 goto numeric; 146 } 147 strncpy(host, buf, hsize); 148 break; 149 } 150 ((struct sockinet *)addr)->si_port = port; 151 } 152#ifdef INET6 153 /* 154 * XXX IPv4 mapped IPv6 addr consideraton, 155 * specified in rfc2373. 156 */ 157 if (sa->sa_family == AF_INET && 158 addr->sa_family == AF_INET6) { 159 struct in_addr *in; 160 struct in6_addr *in6; 161 162 in = &((struct sockaddr_in *)sa)->sin_addr; 163 in6 = &((struct sockaddr_in6 *)addr)->sin6_addr; 164 if (IN6_IS_ADDR_V4MAPPED(in6) && 165 !memcmp(&in6->s6_addr[12], in, 166 sizeof(*in))) { 167 result = HOSTNAME_FOUND; 168 if (ores->ai_canonname == 0 || 169 strlen(ores->ai_canonname) > hsize) { 170 freeaddrinfo(ores); 171 goto numeric; 172 } 173 strncpy(host, ores->ai_canonname, 174 hsize); 175 break; 176 } 177 } 178#endif 179 } 180 freeaddrinfo(ores); 181 } else { 182 struct sockaddr_in sin; 183 numeric: 184#ifdef INET6 185 if (addr->sa_family == AF_INET6) { 186 struct sockaddr_in6 *sin6; 187 188 sin6 = (struct sockaddr_in6 *)addr; 189 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) { 190 memset(&sin, 0, sizeof(sin)); 191 sin.sin_len = sizeof(struct sockaddr_in); 192 sin.sin_family = AF_INET; 193 sin.sin_port = sin6->sin6_port; 194 memcpy(&sin.sin_addr, 195 &sin6->sin6_addr.s6_addr[12], 196 sizeof(struct in_addr)); 197 addr = (struct sockaddr *)&sin; 198 addrlen = sin.sin_len; 199 } 200 } 201#endif 202 if (getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0, 203 NI_NUMERICHOST|NI_WITHSCOPEID) == 0) 204 strncpy(host, buf, hsize); 205 } 206 207 return result; 208} 209 210 211