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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: src/lib/libutil/realhostname.c,v 1.18 2005/05/13 16:31:09 ume Exp $");
29
30 #include <sys/param.h>
31 #include <sys/socket.h>
32
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 struct sockinet {
43 u_char si_len;
44 u_char si_family;
45 u_short si_port;
46 };
47
48 int
realhostname(char * host,size_t hsize,const struct in_addr * ip)49 realhostname(char *host, size_t hsize, const struct in_addr *ip)
50 {
51 char trimmed[MAXHOSTNAMELEN];
52 int result;
53 struct hostent *hp;
54
55 result = HOSTNAME_INVALIDADDR;
56 hp = gethostbyaddr((const char *)ip, sizeof(*ip), AF_INET);
57
58 if (hp != NULL) {
59 strlcpy(trimmed, hp->h_name, sizeof(trimmed));
60 trimdomain(trimmed, strlen(trimmed));
61 if (strlen(trimmed) <= 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 == NULL) {
71 result = HOSTNAME_INCORRECTNAME;
72 break;
73 }
74 if (!memcmp(*hp->h_addr_list, ip, sizeof(*ip))) {
75 strncpy(host, trimmed, hsize);
76 return HOSTNAME_FOUND;
77 }
78 }
79 }
80 }
81
82 strncpy(host, inet_ntoa(*ip), hsize);
83
84 return result;
85 }
86
87 int
realhostname_sa(char * host,size_t hsize,struct sockaddr * addr,int addrlen)88 realhostname_sa(char *host, size_t hsize, struct sockaddr *addr, int addrlen)
89 {
90 int result, error;
91 char buf[NI_MAXHOST];
92 #ifdef INET6
93 struct sockaddr_in lsin;
94 #endif
95
96 result = HOSTNAME_INVALIDADDR;
97
98 #ifdef INET6
99 /* IPv4 mapped IPv6 addr consideraton, specified in rfc2373. */
100 if (addr->sa_family == AF_INET6 &&
101 addrlen == sizeof(struct sockaddr_in6) &&
102 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)addr)->sin6_addr)) {
103 struct sockaddr_in6 *sin6;
104
105 sin6 = (struct sockaddr_in6 *)addr;
106
107 memset(&lsin, 0, sizeof(lsin));
108 lsin.sin_len = sizeof(struct sockaddr_in);
109 lsin.sin_family = AF_INET;
110 lsin.sin_port = sin6->sin6_port;
111 memcpy(&lsin.sin_addr, &sin6->sin6_addr.s6_addr[12],
112 sizeof(struct in_addr));
113 addr = (struct sockaddr *)&lsin;
114 addrlen = lsin.sin_len;
115 }
116 #endif
117
118 error = getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0,
119 NI_NAMEREQD);
120 if (error == 0) {
121 struct addrinfo hints, *res, *ores;
122 struct sockaddr *sa;
123
124 memset(&hints, 0, sizeof(struct addrinfo));
125 hints.ai_family = addr->sa_family;
126 hints.ai_flags = AI_CANONNAME | AI_PASSIVE;
127 hints.ai_socktype = SOCK_STREAM;
128
129 error = getaddrinfo(buf, NULL, &hints, &res);
130 if (error) {
131 result = HOSTNAME_INVALIDNAME;
132 goto numeric;
133 }
134 for (ores = res; ; res = res->ai_next) {
135 if (res == NULL) {
136 freeaddrinfo(ores);
137 result = HOSTNAME_INCORRECTNAME;
138 goto numeric;
139 }
140 sa = res->ai_addr;
141 if (sa == NULL) {
142 freeaddrinfo(ores);
143 result = HOSTNAME_INCORRECTNAME;
144 goto numeric;
145 }
146 if (sa->sa_len == addrlen &&
147 sa->sa_family == addr->sa_family) {
148 ((struct sockinet *)sa)->si_port = ((struct sockinet *)addr)->si_port;
149 #ifdef INET6
150 /*
151 * XXX: sin6_socpe_id may not been
152 * filled by DNS
153 */
154 if (sa->sa_family == AF_INET6 &&
155 ((struct sockaddr_in6 *)sa)->sin6_scope_id == 0)
156 ((struct sockaddr_in6 *)sa)->sin6_scope_id = ((struct sockaddr_in6 *)addr)->sin6_scope_id;
157 #endif
158 if (!memcmp(sa, addr, sa->sa_len)) {
159 result = HOSTNAME_FOUND;
160 if (ores->ai_canonname == NULL) {
161 freeaddrinfo(ores);
162 goto numeric;
163 }
164 strlcpy(buf, ores->ai_canonname,
165 sizeof(buf));
166 trimdomain(buf, hsize);
167 if (strlen(buf) > hsize &&
168 addr->sa_family == AF_INET) {
169 freeaddrinfo(ores);
170 goto numeric;
171 }
172 strncpy(host, buf, hsize);
173 break;
174 }
175 }
176 }
177 freeaddrinfo(ores);
178 } else {
179 numeric:
180 if (getnameinfo(addr, addrlen, buf, sizeof(buf), NULL, 0,
181 NI_NUMERICHOST) == 0)
182 strncpy(host, buf, hsize);
183 }
184
185 return result;
186 }
187
188
189