xref: /freebsd/lib/libc/net/map_v4v6.c (revision 8aac90f18aef7c9eea906c3ff9a001ca7b94f375)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * ++Copyright++ 1985, 1988, 1993
5  * -
6  * Copyright (c) 1985, 1988, 1993
7  *    The Regents of the University of California.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  * -
33  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
34  *
35  * Permission to use, copy, modify, and distribute this software for any
36  * purpose with or without fee is hereby granted, provided that the above
37  * copyright notice and this permission notice appear in all copies, and that
38  * the name of Digital Equipment Corporation not be used in advertising or
39  * publicity pertaining to distribution of the document or software without
40  * specific, written prior permission.
41  *
42  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
43  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
44  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
45  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
46  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
47  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
48  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
49  * SOFTWARE.
50  * -
51  * --Copyright--
52  */
53 
54 #include <sys/param.h>
55 #include <sys/socket.h>
56 #include <netinet/in.h>
57 #include <arpa/inet.h>
58 #include <arpa/nameser.h>
59 
60 #include <stdio.h>
61 #include <string.h>
62 #include <netdb.h>
63 #include <resolv.h>
64 #include <ctype.h>
65 #include <syslog.h>
66 #include "netdb_private.h"
67 
68 typedef union {
69 	int32_t al;
70 	char ac;
71 } align;
72 
73 void
74 _map_v4v6_address(const char *src, char *dst)
75 {
76 	/* Our caller may update in place. */
77 	memmove(&dst[12], src, NS_INADDRSZ);
78 	/* Mark this ipv6 addr as a mapped ipv4. */
79 	memset(&dst[10], 0xff, 2);
80 	memset(&dst[0], 0, 10);
81 }
82 
83 void
84 _map_v4v6_hostent(struct hostent *hp, char **bpp, char *ep) {
85 	char **ap;
86 
87 	if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
88 		return;
89 	hp->h_addrtype = AF_INET6;
90 	hp->h_length = IN6ADDRSZ;
91 	for (ap = hp->h_addr_list; *ap; ap++) {
92 		int i = (u_long)*bpp % sizeof(align);
93 
94 		if (i != 0)
95 			i = sizeof(align) - i;
96 
97 		if ((ep - *bpp) < (i + IN6ADDRSZ)) {
98 			/* Out of memory.  Truncate address list here. */
99 			*ap = NULL;
100 			return;
101 		}
102 		*bpp += i;
103 		_map_v4v6_address(*ap, *bpp);
104 		*ap = *bpp;
105 		*bpp += IN6ADDRSZ;
106 	}
107 }
108