1 /*	$NetBSD: inet_ntop.c,v 1.1.1.1 2011/04/13 18:15:41 elric Exp $	*/
2 
3 /*
4  * Copyright (c) 1999 - 2001 Kungliga Tekniska Högskolan
5  * (Royal Institute of Technology, Stockholm, Sweden).
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * 3. Neither the name of the Institute nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <config.h>
37 
38 #include <krb5/roken.h>
39 
40 /*
41  *
42  */
43 
44 static const char *
45 inet_ntop_v4 (const void *src, char *dst, size_t size)
46 {
47     const char digits[] = "0123456789";
48     int i;
49     struct in_addr *addr = (struct in_addr *)src;
50     u_long a = ntohl(addr->s_addr);
51     const char *orig_dst = dst;
52 
53     if (size < INET_ADDRSTRLEN) {
54 	errno = ENOSPC;
55 	return NULL;
56     }
57     for (i = 0; i < 4; ++i) {
58 	int n = (a >> (24 - i * 8)) & 0xFF;
59 	int non_zerop = 0;
60 
61 	if (non_zerop || n / 100 > 0) {
62 	    *dst++ = digits[n / 100];
63 	    n %= 100;
64 	    non_zerop = 1;
65 	}
66 	if (non_zerop || n / 10 > 0) {
67 	    *dst++ = digits[n / 10];
68 	    n %= 10;
69 	    non_zerop = 1;
70 	}
71 	*dst++ = digits[n];
72 	if (i != 3)
73 	    *dst++ = '.';
74     }
75     *dst++ = '\0';
76     return orig_dst;
77 }
78 
79 #ifdef HAVE_IPV6
80 static const char *
81 inet_ntop_v6 (const void *src, char *dst, size_t size)
82 {
83     const char xdigits[] = "0123456789abcdef";
84     int i;
85     const struct in6_addr *addr = (struct in6_addr *)src;
86     const u_char *ptr = addr->s6_addr;
87     const char *orig_dst = dst;
88     int compressed = 0;
89 
90     if (size < INET6_ADDRSTRLEN) {
91 	errno = ENOSPC;
92 	return NULL;
93     }
94     for (i = 0; i < 8; ++i) {
95 	int non_zerop = 0;
96 
97         if (compressed == 0 &&
98             ptr[0] == 0 && ptr[1] == 0 &&
99             i <= 5 &&
100             ptr[2] == 0 && ptr[3] == 0 &&
101             ptr[4] == 0 && ptr[5] == 0) {
102 
103             compressed = 1;
104 
105             if (i == 0)
106                 *dst++ = ':';
107             *dst++ = ':';
108 
109             for (ptr += 6, i += 3;
110                  i < 8 && ptr[0] == 0 && ptr[1] == 0;
111                  ++i, ptr += 2);
112 
113             if (i >= 8)
114                 break;
115         }
116 
117 	if (non_zerop || (ptr[0] >> 4)) {
118 	    *dst++ = xdigits[ptr[0] >> 4];
119 	    non_zerop = 1;
120 	}
121 	if (non_zerop || (ptr[0] & 0x0F)) {
122 	    *dst++ = xdigits[ptr[0] & 0x0F];
123 	    non_zerop = 1;
124 	}
125 	if (non_zerop || (ptr[1] >> 4)) {
126 	    *dst++ = xdigits[ptr[1] >> 4];
127 	    non_zerop = 1;
128 	}
129 	*dst++ = xdigits[ptr[1] & 0x0F];
130 	if (i != 7)
131 	    *dst++ = ':';
132 	ptr += 2;
133     }
134     *dst++ = '\0';
135     return orig_dst;
136 }
137 #endif /* HAVE_IPV6 */
138 
139 ROKEN_LIB_FUNCTION const char * ROKEN_LIB_CALL
140 inet_ntop(int af, const void *src, char *dst, size_t size)
141 {
142     switch (af) {
143     case AF_INET :
144 	return inet_ntop_v4 (src, dst, size);
145 #ifdef HAVE_IPV6
146     case AF_INET6 :
147 	return inet_ntop_v6 (src, dst, size);
148 #endif
149     default :
150 	errno = EAFNOSUPPORT;
151 	return NULL;
152     }
153 }
154