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 1.3.18.2 2005/11/03 23:02:22 marka Exp $
18 * FreeBSD r213103
19 */
20
21 #include <sys/param.h>
22 #include <sys/socket.h>
23 #include <sys/systm.h>
24
25 #include <netinet/in.h>
26
27 /*%
28 * WARNING: Don't even consider trying to compile this on a system where
29 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
30 */
31
32 static char *inet_ntop4(const u_char *src, char *dst, socklen_t size);
33 static char *inet_ntop6(const u_char *src, char *dst, socklen_t size);
34
35 /* char *
36 * inet_ntop(af, src, dst, size)
37 * convert a network format address to presentation format.
38 * return:
39 * pointer to presentation format address (`dst'), or NULL (see errno).
40 * author:
41 * Paul Vixie, 1996.
42 */
43 char *
inet_ntop(int af,const void * src,char * dst,socklen_t size)44 inet_ntop(int af, const void *src, char *dst, socklen_t size)
45 {
46 switch (af) {
47 case AF_INET:
48 return (inet_ntop4(src, dst, size));
49 case AF_INET6:
50 return (inet_ntop6(src, dst, size));
51 default:
52 return (NULL);
53 }
54 /* NOTREACHED */
55 }
56
57 /* const char *
58 * inet_ntop4(src, dst, size)
59 * format an IPv4 address
60 * return:
61 * `dst' (as a const)
62 * notes:
63 * (1) uses no statics
64 * (2) takes a u_char* not an in_addr as input
65 * author:
66 * Paul Vixie, 1996.
67 */
68 static char *
inet_ntop4(const u_char * src,char * dst,socklen_t size)69 inet_ntop4(const u_char *src, char *dst, socklen_t size)
70 {
71 static const char fmt[] = "%u.%u.%u.%u";
72 char tmp[sizeof "255.255.255.255"];
73 int l;
74
75 l = ksnprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
76 if (l <= 0 || (socklen_t) l >= size) {
77 return (NULL);
78 }
79 strlcpy(dst, tmp, size);
80 return (dst);
81 }
82
83 /* const char *
84 * inet_ntop6(src, dst, size)
85 * convert IPv6 binary address into presentation (printable) format
86 * author:
87 * Paul Vixie, 1996.
88 */
89 static char *
inet_ntop6(const u_char * src,char * dst,socklen_t size)90 inet_ntop6(const u_char *src, char *dst, socklen_t size)
91 {
92 /*
93 * Note that int32_t and int16_t need only be "at least" large enough
94 * to contain a value of the specified size. On some systems, like
95 * Crays, there is no such thing as an integer variable with 16 bits.
96 * Keep this in mind if you think this function should have been coded
97 * to use pointer overlays. All the world's not a VAX.
98 */
99 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
100 struct { int base, len; } best, cur;
101 #define NS_IN6ADDRSZ 16
102 #define NS_INT16SZ 2
103 u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
104 int i;
105
106 /*
107 * Preprocess:
108 * Copy the input (bytewise) array into a wordwise array.
109 * Find the longest run of 0x00's in src[] for :: shorthanding.
110 */
111 memset(words, '\0', sizeof words);
112 for (i = 0; i < NS_IN6ADDRSZ; i++)
113 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
114 best.base = -1;
115 best.len = 0;
116 cur.base = -1;
117 cur.len = 0;
118 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
119 if (words[i] == 0) {
120 if (cur.base == -1)
121 cur.base = i, cur.len = 1;
122 else
123 cur.len++;
124 } else {
125 if (cur.base != -1) {
126 if (best.base == -1 || cur.len > best.len)
127 best = cur;
128 cur.base = -1;
129 }
130 }
131 }
132 if (cur.base != -1) {
133 if (best.base == -1 || cur.len > best.len)
134 best = cur;
135 }
136 if (best.base != -1 && best.len < 2)
137 best.base = -1;
138
139 /*
140 * Format the result.
141 */
142 tp = tmp;
143 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
144 /* Are we inside the best run of 0x00's? */
145 if (best.base != -1 && i >= best.base &&
146 i < (best.base + best.len)) {
147 if (i == best.base)
148 *tp++ = ':';
149 continue;
150 }
151 /* Are we following an initial run of 0x00s or any real hex? */
152 if (i != 0)
153 *tp++ = ':';
154 /* Is this address an encapsulated IPv4? */
155 if (i == 6 && best.base == 0 && (best.len == 6 ||
156 (best.len == 7 && words[7] != 0x0001) ||
157 (best.len == 5 && words[5] == 0xffff))) {
158 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
159 return (NULL);
160 tp += strlen(tp);
161 break;
162 }
163 tp += ksprintf(tp, "%x", words[i]);
164 }
165 /* Was it a trailing run of 0x00's? */
166 if (best.base != -1 && (best.base + best.len) ==
167 (NS_IN6ADDRSZ / NS_INT16SZ))
168 *tp++ = ':';
169 *tp++ = '\0';
170
171 /*
172 * Check for overflow, copy, and we're done.
173 */
174 if ((socklen_t)(tp - tmp) > size) {
175 return (NULL);
176 }
177 strcpy(dst, tmp);
178 return (dst);
179 }
180
181 /*! \file */
182