1 /*
2 * Copyright (c) 1996 by Internet Software Consortium.
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
9 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
11 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
12 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
13 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
14 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
15 * SOFTWARE.
16 */
17
18 /*
19 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
20 * Use is subject to license terms.
21 */
22
23 #include "lint.h"
24
25 #include <sys/socket.h>
26
27 #include <arpa/inet.h>
28 #include <netinet/in.h>
29
30 #include <ctype.h>
31 #include <errno.h>
32 #include <netdb.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <strings.h>
37
38 static const char *inet_ntop4(const uchar_t *, char *, socklen_t);
39 static const char *inet_ntop6(const uchar_t *, char *, socklen_t);
40
41 /*
42 * char *
43 * inet_ntop(af, src, dst, size)
44 * convert a network format address to presentation format.
45 * return:
46 * pointer to presentation format address (`dst'), or NULL (see errno).
47 */
48 const char *
inet_ntop(int af,const void * src,char * dst,socklen_t size)49 inet_ntop(int af, const void *src, char *dst, socklen_t size)
50 {
51 switch (af) {
52 case AF_INET:
53 return (inet_ntop4(src, dst, size));
54 case AF_INET6:
55 return (inet_ntop6(src, dst, size));
56 default:
57 errno = EAFNOSUPPORT;
58 return (NULL);
59 }
60 /* NOTREACHED */
61 }
62
63 /*
64 * const char *
65 * inet_ntop4(src, dst, size)
66 * format an IPv4 address, more or less like inet_ntoa()
67 * return:
68 * `dst' (as a const)
69 * notes:
70 * (1) uses no statics
71 * (2) takes a uchar_t* not an in_addr as input
72 */
73
74 static const char *
inet_ntop4(const uchar_t * src,char * dst,socklen_t size)75 inet_ntop4(const uchar_t *src, char *dst, socklen_t size)
76 {
77 static const char fmt[] = "%u.%u.%u.%u";
78 char tmp[sizeof ("255.255.255.255")];
79
80 if (sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) > size) {
81 errno = ENOSPC;
82 return (NULL);
83 }
84 (void) strcpy(dst, tmp);
85 return (dst);
86 }
87
88 /*
89 * const char *
90 * inet_ntop6(src, dst, size)
91 * convert IPv6 binary address into presentation (printable) format
92 */
93 #define INADDRSZ 4
94 #define IN6ADDRSZ 16
95 #define INT16SZ 2
96 static const char *
inet_ntop6(const uchar_t * src,char * dst,socklen_t size)97 inet_ntop6(const uchar_t *src, char *dst, socklen_t size)
98 {
99 /*
100 * Note that int32_t and int16_t need only be "at least" large enough
101 * to contain a value of the specified size. On some systems, like
102 * Crays, there is no such thing as an integer variable with 16 bits.
103 * Keep this in mind if you think this function should have been coded
104 * to use pointer overlays. All the world's not a VAX.
105 */
106 char tmp[sizeof ("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
107 struct { int base, len; } best, cur;
108 uint_t words[IN6ADDRSZ / INT16SZ];
109 int i;
110
111 /*
112 * Preprocess:
113 * Copy the input (bytewise) array into a wordwise array.
114 * Find the longest run of 0x00's in src[] for :: shorthanding.
115 */
116 (void) memset(words, '\0', sizeof (words));
117 for (i = 0; i < IN6ADDRSZ; i++)
118 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
119 best.base = -1;
120 cur.base = -1;
121 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
122 if (words[i] == 0) {
123 if (cur.base == -1)
124 cur.base = i, cur.len = 1;
125 else
126 cur.len++;
127 } else {
128 if (cur.base != -1) {
129 if (best.base == -1 || cur.len > best.len)
130 best = cur;
131 cur.base = -1;
132 }
133 }
134 }
135 if (cur.base != -1) {
136 if (best.base == -1 || cur.len > best.len)
137 best = cur;
138 }
139 if (best.base != -1 && best.len < 2)
140 best.base = -1;
141
142 /*
143 * Format the result.
144 */
145 tp = tmp;
146 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
147 /* Are we inside the best run of 0x00's? */
148 if (best.base != -1 && i >= best.base &&
149 i < (best.base + best.len)) {
150 if (i == best.base)
151 *tp++ = ':';
152 continue;
153 }
154 /* Are we following an initial run of 0x00s or any real hex? */
155 if (i != 0)
156 *tp++ = ':';
157 /* Is this address an encapsulated IPv4? */
158 if (i == 6 && best.base == 0 &&
159 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
160 if (!inet_ntop4(src+12, tp, sizeof (tmp) - (tp - tmp)))
161 return (NULL);
162 tp += strlen(tp);
163 break;
164 }
165 tp += sprintf(tp, "%x", words[i]);
166 }
167 /* Was it a trailing run of 0x00's? */
168 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
169 *tp++ = ':';
170 *tp++ = '\0';
171
172 /*
173 * Check for overflow, copy, and we're done.
174 */
175 if ((int)(tp - tmp) > size) {
176 errno = ENOSPC;
177 return (NULL);
178 }
179 (void) strcpy(dst, tmp);
180 return (dst);
181 }
182