1 /*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996-1999 by Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and 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
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 *
17 * $Id: inet_ntop.c,v 1.5 2005/11/03 22:59:52 marka Exp $
18 */
19
20 #include "port_before.h"
21
22 #include <sys/param.h>
23 #include <sys/types.h>
24 #include <sys/socket.h>
25
26 #include <netinet/in.h>
27 #include "arpa/inet.h"
28 #include <arpa/nameser.h>
29
30 #include <errno.h>
31 #include <stdio.h>
32 #include <string.h>
33
34 #include "port_after.h"
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 u_char *src, char *dst, size_t size);
42 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
43
44 /* const char *
45 * inet_ntop(af, src, dst, size)
46 * convert a network format address to presentation format.
47 * return:
48 * pointer to presentation format address (`dst'), or NULL (see errno).
49 * author:
50 * Paul Vixie, 1996.
51 */
52 const char *
inet_ntop(int af,const void * __restrict src,char * __restrict dst,socklen_t size)53 inet_ntop(int af, const void * __restrict src, char * __restrict dst,
54 socklen_t size)
55 {
56 switch (af) {
57 case AF_INET:
58 return (inet_ntop4(src, dst, size));
59 case AF_INET6:
60 return (inet_ntop6(src, dst, size));
61 default:
62 errno = EAFNOSUPPORT;
63 return (NULL);
64 }
65 /* NOTREACHED */
66 }
67
68 /* const char *
69 * inet_ntop4(src, dst, size)
70 * format an IPv4 address
71 * return:
72 * `dst' (as a const)
73 * notes:
74 * (1) uses no statics
75 * (2) takes a u_char* not an in_addr as input
76 * author:
77 * Paul Vixie, 1996.
78 */
79 static const char *
inet_ntop4(const u_char * src,char * dst,size_t size)80 inet_ntop4(const u_char *src, char *dst, size_t size)
81 {
82 static const char fmt[] = "%u.%u.%u.%u";
83 char tmp[sizeof "255.255.255.255"];
84 int l;
85
86 l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
87 if (l <= 0 || (socklen_t)l >= size) {
88 errno = ENOSPC;
89 return (NULL);
90 }
91 strlcpy(dst, tmp, size);
92 return (dst);
93 }
94
95 /* const char *
96 * inet_ntop6(src, dst, size)
97 * convert IPv6 binary address into presentation (printable) format
98 * author:
99 * Paul Vixie, 1996.
100 */
101 static const char *
inet_ntop6(const u_char * src,char * dst,size_t size)102 inet_ntop6(const u_char *src, char *dst, size_t size)
103 {
104 /*
105 * Note that int32_t and int16_t need only be "at least" large enough
106 * to contain a value of the specified size. On some systems, like
107 * Crays, there is no such thing as an integer variable with 16 bits.
108 * Keep this in mind if you think this function should have been coded
109 * to use pointer overlays. All the world's not a VAX.
110 */
111 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
112 struct { int base, len; } best, cur;
113 u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
114 int i;
115
116 /*
117 * Preprocess:
118 * Copy the input (bytewise) array into a wordwise array.
119 * Find the longest run of 0x00's in src[] for :: shorthanding.
120 */
121 memset(words, '\0', sizeof words);
122 for (i = 0; i < NS_IN6ADDRSZ; i++)
123 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
124 best.base = -1;
125 best.len = 0;
126 cur.base = -1;
127 cur.len = 0;
128 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
129 if (words[i] == 0) {
130 if (cur.base == -1)
131 cur.base = i, cur.len = 1;
132 else
133 cur.len++;
134 } else {
135 if (cur.base != -1) {
136 if (best.base == -1 || cur.len > best.len)
137 best = cur;
138 cur.base = -1;
139 }
140 }
141 }
142 if (cur.base != -1) {
143 if (best.base == -1 || cur.len > best.len)
144 best = cur;
145 }
146 if (best.base != -1 && best.len < 2)
147 best.base = -1;
148
149 /*
150 * Format the result.
151 */
152 tp = tmp;
153 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
154 /* Are we inside the best run of 0x00's? */
155 if (best.base != -1 && i >= best.base &&
156 i < (best.base + best.len)) {
157 if (i == best.base)
158 *tp++ = ':';
159 continue;
160 }
161 /* Are we following an initial run of 0x00s or any real hex? */
162 if (i != 0)
163 *tp++ = ':';
164 /* Is this address an encapsulated IPv4? */
165 if (i == 6 && best.base == 0 && (best.len == 6 ||
166 (best.len == 7 && words[7] != 0x0001) ||
167 (best.len == 5 && words[5] == 0xffff))) {
168 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) {
169 errno = ENOSPC;
170 return (NULL);
171 }
172 tp += strlen(tp);
173 break;
174 }
175 tp += sprintf(tp, "%x", words[i]);
176 }
177 /* Was it a trailing run of 0x00's? */
178 if (best.base != -1 && (best.base + best.len) ==
179 (NS_IN6ADDRSZ / NS_INT16SZ))
180 *tp++ = ':';
181 *tp++ = '\0';
182
183 /*
184 * Check for overflow, copy, and we're done.
185 */
186 if ((socklen_t)(tp - tmp) > size) {
187 errno = ENOSPC;
188 return (NULL);
189 }
190 strcpy(dst, tmp);
191 return (dst);
192 }
193
194 /*
195 * Weak aliases for applications that use certain private entry points,
196 * and fail to include <arpa/inet.h>.
197 */
198 #undef inet_ntop
199 __weak_reference(__inet_ntop, inet_ntop);
200