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 * $FreeBSD$ 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 int result; 56 struct hostent *hp; 57 58 result = HOSTNAME_INVALIDADDR; 59 hp = gethostbyaddr((char *)ip, sizeof(*ip), AF_INET); 60 61 if (hp != NULL && strlen(hp->h_name) <= hsize) { 62 char lookup[MAXHOSTNAMELEN]; 63 64 strncpy(lookup, hp->h_name, sizeof(lookup) - 1); 65 lookup[sizeof(lookup) - 1] = '\0'; 66 hp = gethostbyname(lookup); 67 if (hp == NULL) 68 result = HOSTNAME_INVALIDNAME; 69 else for (; ; hp->h_addr_list++) { 70 if (hp->h_addr_list[0] == NULL) { 71 result = HOSTNAME_INCORRECTNAME; 72 break; 73 } 74 if (!memcmp(*hp->h_addr_list, ip, sizeof(*ip))) { 75 strncpy(host, lookup, hsize); 76 return HOSTNAME_FOUND; 77 } 78 } 79 } 80 81 strncpy(host, inet_ntoa(*ip), hsize); 82 83 return result; 84 } 85 86 int 87 realhostname_sa(char *host, size_t hsize, struct sockaddr *addr, int addrlen) 88 { 89 int result, error; 90 91 result = HOSTNAME_INVALIDADDR; 92 93 error = getnameinfo(addr, addrlen, host, hsize, NULL, 0, 0); 94 if (error == NULL) { 95 struct addrinfo hints, *res, *ores; 96 struct sockaddr *sa; 97 98 memset(&hints, 0, sizeof(struct addrinfo)); 99 hints.ai_family = AF_UNSPEC; 100 hints.ai_flags = AI_CANONNAME; 101 102 error = getaddrinfo(host, NULL, &hints, &res); 103 if (error) { 104 result = HOSTNAME_INVALIDNAME; 105 goto numeric; 106 } else for (ores = res; ; res = res->ai_next) { 107 if (res == NULL) { 108 freeaddrinfo(ores); 109 result = HOSTNAME_INCORRECTNAME; 110 goto numeric; 111 } 112 sa = res->ai_addr; 113 if (sa == NULL) { 114 freeaddrinfo(ores); 115 result = HOSTNAME_INCORRECTNAME; 116 goto numeric; 117 } 118 if (sa->sa_len == addrlen && 119 sa->sa_family == addr->sa_family) { 120 u_int16_t port; 121 122 port = ((struct sockinet *)addr)->si_port; 123 ((struct sockinet *)addr)->si_port = 0; 124 if (!memcmp(sa, addr, sa->sa_len)) { 125 if (res->ai_canonname != 0) 126 strncpy(host, 127 res->ai_canonname, 128 hsize); 129 result = HOSTNAME_FOUND; 130 ((struct sockinet *)addr)->si_port = 131 port; 132 break; 133 } 134 ((struct sockinet *)addr)->si_port = port; 135 } 136 #ifdef INET6 137 /* 138 * XXX IPv4 mapped IPv6 addr consideraton, 139 * specified in rfc2373. 140 */ 141 if (sa->sa_family == AF_INET && 142 addr->sa_family == AF_INET6) { 143 struct in_addr *in; 144 struct in6_addr *in6; 145 146 in = &((struct sockaddr_in *)sa)->sin_addr; 147 in6 = &((struct sockaddr_in6 *)addr)->sin6_addr; 148 if (IN6_IS_ADDR_V4MAPPED(in6) && 149 !memcmp(&in6->s6_addr[12], in, 150 sizeof(*in))) { 151 if (res->ai_canonname != 0) 152 strncpy(host, 153 res->ai_canonname, 154 hsize); 155 result = HOSTNAME_FOUND; 156 break; 157 } 158 } 159 #endif 160 } 161 freeaddrinfo(ores); 162 } else { 163 numeric: 164 getnameinfo(addr, addrlen, host, hsize, NULL, 0, 165 NI_NUMERICHOST|NI_WITHSCOPEID); 166 /* XXX: do 'error' check */ 167 } 168 169 return result; 170 } 171 172 173