1 /*
2 * Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1996-2001, 2003 Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 /*! \file lwinetntop.c
19 */
20 #if defined(LIBC_SCCS) && !defined(lint)
21 static char rcsid[] =
22 "$Id: lwinetntop.c,v 1.18 2007/06/19 23:47:22 tbox Exp $";
23 #endif /* LIBC_SCCS and not lint */
24
25 #include <config.h>
26
27 #include <errno.h>
28 #include <stdio.h>
29 #include <string.h>
30
31 #include <lwres/net.h>
32 #include "print_p.h"
33
34 #define NS_INT16SZ 2
35 #define NS_IN6ADDRSZ 16
36
37 /*
38 * WARNING: Don't even consider trying to compile this on a system where
39 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
40 */
41
42 static const char *inet_ntop4(const unsigned char *src, char *dst,
43 size_t size);
44
45 #ifdef AF_INET6
46 static const char *inet_ntop6(const unsigned char *src, char *dst,
47 size_t size);
48 #endif
49
50 /*! char *
51 * lwres_net_ntop(af, src, dst, size)
52 * convert a network format address to presentation format.
53 * return:
54 * pointer to presentation format address (`dst'), or NULL (see errno).
55 * author:
56 * Paul Vixie, 1996.
57 */
58 const char *
lwres_net_ntop(int af,const void * src,char * dst,size_t size)59 lwres_net_ntop(int af, const void *src, char *dst, size_t size) {
60 switch (af) {
61 case AF_INET:
62 return (inet_ntop4(src, dst, size));
63 #ifdef AF_INET6
64 case AF_INET6:
65 return (inet_ntop6(src, dst, size));
66 #endif
67 default:
68 errno = EAFNOSUPPORT;
69 return (NULL);
70 }
71 /* NOTREACHED */
72 }
73
74 /*! const char *
75 * inet_ntop4(src, dst, size)
76 * format an IPv4 address
77 * return:
78 * `dst' (as a const)
79 * notes:
80 * (1) uses no statics
81 * (2) takes a unsigned char* not an in_addr as input
82 * author:
83 * Paul Vixie, 1996.
84 */
85 static const char *
inet_ntop4(const unsigned char * src,char * dst,size_t size)86 inet_ntop4(const unsigned char *src, char *dst, size_t size) {
87 static const char fmt[] = "%u.%u.%u.%u";
88 char tmp[sizeof("255.255.255.255")];
89 size_t len;
90
91 len = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
92 if (len >= size) {
93 errno = ENOSPC;
94 return (NULL);
95 }
96 strcpy(dst, tmp);
97
98 return (dst);
99 }
100
101 /*! const char *
102 * inet_ntop6(src, dst, size)
103 * convert IPv6 binary address into presentation (printable) format
104 * author:
105 * Paul Vixie, 1996.
106 */
107 #ifdef AF_INET6
108 static const char *
inet_ntop6(const unsigned char * src,char * dst,size_t size)109 inet_ntop6(const unsigned char *src, char *dst, size_t size) {
110 /*!
111 * Note that int32_t and int16_t need only be "at least" large enough
112 * to contain a value of the specified size. On some systems, like
113 * Crays, there is no such thing as an integer variable with 16 bits.
114 * Keep this in mind if you think this function should have been coded
115 * to use pointer overlays. All the world's not a VAX.
116 */
117 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
118 struct { int base, len; } best, cur;
119 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
120 int i;
121
122 /*
123 * Preprocess:
124 * Copy the input (bytewise) array into a wordwise array.
125 * Find the longest run of 0x00's in src[] for :: shorthanding.
126 */
127 memset(words, '\0', sizeof(words));
128 for (i = 0; i < NS_IN6ADDRSZ; i++)
129 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
130 best.base = -1;
131 best.len = 0;
132 cur.base = -1;
133 cur.len = 0;
134 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
135 if (words[i] == 0) {
136 if (cur.base == -1)
137 cur.base = i, cur.len = 1;
138 else
139 cur.len++;
140 } else {
141 if (cur.base != -1) {
142 if (best.base == -1 || cur.len > best.len)
143 best = cur;
144 cur.base = -1;
145 }
146 }
147 }
148 if (cur.base != -1) {
149 if (best.base == -1 || cur.len > best.len)
150 best = cur;
151 }
152 if (best.base != -1 && best.len < 2)
153 best.base = -1;
154
155 /*
156 * Format the result.
157 */
158 tp = tmp;
159 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
160 /* Are we inside the best run of 0x00's? */
161 if (best.base != -1 && i >= best.base &&
162 i < (best.base + best.len)) {
163 if (i == best.base)
164 *tp++ = ':';
165 continue;
166 }
167 /* Are we following an initial run of 0x00s or any real hex? */
168 if (i != 0)
169 *tp++ = ':';
170 /* Is this address an encapsulated IPv4? */
171 if (i == 6 && best.base == 0 &&
172 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
173 if (!inet_ntop4(src+12, tp,
174 sizeof(tmp) - (tp - tmp)))
175 return (NULL);
176 tp += strlen(tp);
177 break;
178 }
179 tp += sprintf(tp, "%x", words[i]); /* XXX */
180 }
181 /* Was it a trailing run of 0x00's? */
182 if (best.base != -1 && (best.base + best.len) ==
183 (NS_IN6ADDRSZ / NS_INT16SZ))
184 *tp++ = ':';
185 *tp++ = '\0';
186
187 /*
188 * Check for overflow, copy, and we're done.
189 */
190 if ((size_t)(tp - tmp) > size) {
191 errno = ENOSPC;
192 return (NULL);
193 }
194 strcpy(dst, tmp);
195 return (dst);
196 }
197 #endif /* AF_INET6 */
198