1 /* $NetBSD: inet_ntop.c,v 1.10 2007/07/23 11:45:51 lukem Exp $ */
2 /* from NetBSD: inet_ntop.c,v 1.3 2006/05/10 21:53:15 mrg Exp */
3
4 /*
5 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
6 * Copyright (c) 1996-1999 by Internet Software Consortium.
7 *
8 * Permission to use, copy, modify, and distribute this software for any
9 * purpose with or without fee is hereby granted, provided that the above
10 * copyright notice and this permission notice appear in all copies.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
13 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
14 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
15 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
16 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
17 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
18 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19 */
20
21 #include "tnftp.h"
22
23 #if defined(HAVE_ARPA_NAMESER_H)
24 # include <arpa/nameser.h>
25 #endif
26 #if !defined(NS_INADDRSZ)
27 # define NS_INADDRSZ 4
28 #endif
29 #if !defined(NS_IN6ADDRSZ)
30 # define NS_IN6ADDRSZ 16
31 #endif
32 #if !defined(NS_INT16SZ)
33 # define NS_INT16SZ 2
34 #endif
35
36 /*
37 * WARNING: Don't even consider trying to compile this on a system where
38 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
39 */
40
41 static const char *inet_ntop4(const unsigned char *src, char *dst, socklen_t size);
42 #ifdef INET6
43 static const char *inet_ntop6(const unsigned char *src, char *dst, socklen_t size);
44 #endif /* INET6 */
45
46 /* char *
47 * inet_ntop(af, src, dst, size)
48 * convert a network format address to presentation format.
49 * return:
50 * pointer to presentation format address (`dst'), or NULL (see errno).
51 * author:
52 * Paul Vixie, 1996.
53 */
54 const char *
inet_ntop(int af,const void * src,char * dst,socklen_t size)55 inet_ntop(int af, const void *src, char *dst, socklen_t size)
56 {
57
58 switch (af) {
59 case AF_INET:
60 return (inet_ntop4(src, dst, size));
61 #ifdef INET6
62 case AF_INET6:
63 return (inet_ntop6(src, dst, size));
64 #endif /* INET6 */
65 default:
66 errno = EAFNOSUPPORT;
67 return (NULL);
68 }
69 /* NOTREACHED */
70 }
71
72 /* const char *
73 * inet_ntop4(src, dst, size)
74 * format an IPv4 address, more or less like inet_ntoa()
75 * return:
76 * `dst' (as a const)
77 * notes:
78 * (1) uses no statics
79 * (2) takes a unsigned char* not an in_addr as input
80 * author:
81 * Paul Vixie, 1996.
82 */
83 static const char *
inet_ntop4(const unsigned char * src,char * dst,socklen_t size)84 inet_ntop4(const unsigned char *src, char *dst, socklen_t size)
85 {
86 char tmp[sizeof "255.255.255.255"];
87 int l;
88
89 l = snprintf(tmp, sizeof(tmp), "%u.%u.%u.%u",
90 src[0], src[1], src[2], src[3]);
91 if (l <= 0 || (socklen_t) l >= size) {
92 errno = ENOSPC;
93 return (NULL);
94 }
95 strlcpy(dst, tmp, size);
96 return (dst);
97 }
98
99 #ifdef INET6
100 /* const char *
101 * inet_ntop6(src, dst, size)
102 * convert IPv6 binary address into presentation (printable) format
103 * author:
104 * Paul Vixie, 1996.
105 */
106 static const char *
inet_ntop6(const unsigned char * src,char * dst,socklen_t size)107 inet_ntop6(const unsigned char *src, char *dst, socklen_t size)
108 {
109 /*
110 * Note that int32_t and int16_t need only be "at least" large enough
111 * to contain a value of the specified size. On some systems, like
112 * Crays, there is no such thing as an integer variable with 16 bits.
113 * Keep this in mind if you think this function should have been coded
114 * to use pointer overlays. All the world's not a VAX.
115 */
116 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
117 char *tp, *ep;
118 struct { int base, len; } best, cur;
119 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
120 int i;
121 int advance;
122
123 /*
124 * Preprocess:
125 * Copy the input (bytewise) array into a wordwise array.
126 * Find the longest run of 0x00's in src[] for :: shorthanding.
127 */
128 memset(words, '\0', sizeof words);
129 for (i = 0; i < NS_IN6ADDRSZ; i++)
130 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
131 best.base = -1;
132 cur.base = -1;
133 best.len = -1; /* XXX gcc */
134 cur.len = -1; /* XXX gcc */
135 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
136 if (words[i] == 0) {
137 if (cur.base == -1)
138 cur.base = i, cur.len = 1;
139 else
140 cur.len++;
141 } else {
142 if (cur.base != -1) {
143 if (best.base == -1 || cur.len > best.len)
144 best = cur;
145 cur.base = -1;
146 }
147 }
148 }
149 if (cur.base != -1) {
150 if (best.base == -1 || cur.len > best.len)
151 best = cur;
152 }
153 if (best.base != -1 && best.len < 2)
154 best.base = -1;
155
156 /*
157 * Format the result.
158 */
159 tp = tmp;
160 ep = tmp + sizeof(tmp);
161 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
162 /* Are we inside the best run of 0x00's? */
163 if (best.base != -1 && i >= best.base &&
164 i < (best.base + best.len)) {
165 if (i == best.base)
166 *tp++ = ':';
167 continue;
168 }
169 /* Are we following an initial run of 0x00s or any real hex? */
170 if (i != 0) {
171 if (tp + 1 >= ep)
172 return (NULL);
173 *tp++ = ':';
174 }
175 /* Is this address an encapsulated IPv4? */
176 if (i == 6 && best.base == 0 &&
177 (best.len == 6 ||
178 (best.len == 7 && words[7] != 0x0001) ||
179 (best.len == 5 && words[5] == 0xffff))) {
180 if (!inet_ntop4(src+12, tp, (socklen_t)(ep - tp)))
181 return (NULL);
182 tp += strlen(tp);
183 break;
184 }
185 advance = snprintf(tp, (size_t)(ep - tp), "%x", words[i]);
186 if (advance <= 0 || advance >= ep - tp)
187 return (NULL);
188 tp += advance;
189 }
190 /* Was it a trailing run of 0x00's? */
191 if (best.base != -1 && (best.base + best.len) ==
192 (NS_IN6ADDRSZ / NS_INT16SZ)) {
193 if (tp + 1 >= ep)
194 return (NULL);
195 *tp++ = ':';
196 }
197 if (tp + 1 >= ep)
198 return (NULL);
199 *tp++ = '\0';
200
201 /*
202 * Check for overflow, copy, and we're done.
203 */
204 if ((size_t)(tp - tmp) > size) {
205 errno = ENOSPC;
206 return (NULL);
207 }
208 strlcpy(dst, tmp, size);
209 return (dst);
210 }
211 #endif /* INET6 */
212