1 /* From openssh 4.3p2 compat/inet_ntop.c */
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 /* OPENBSD ORIGINAL: lib/libc/net/inet_ntop.c */
19
20 #include <config.h>
21
22 #ifndef HAVE_INET_NTOP
23
24 #include <sys/param.h>
25 #include <sys/types.h>
26 #include <sys/socket.h>
27 #include <netinet/in.h>
28 #include <string.h>
29 #include <errno.h>
30 #include <stdio.h>
31
32 #ifndef IN6ADDRSZ
33 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */
34 #endif
35
36 #ifndef INT16SZ
37 #define INT16SZ 2 /* for systems without 16-bit ints */
38 #endif
39
40 /*
41 * WARNING: Don't even consider trying to compile this on a system where
42 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
43 */
44
45 static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
46 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
47
48 /* char *
49 * inet_ntop(af, src, dst, size)
50 * convert a network format address to presentation format.
51 * return:
52 * pointer to presentation format address (`dst'), or NULL (see errno).
53 * author:
54 * Paul Vixie, 1996.
55 */
56 const char *
inet_ntop(int af,const void * src,char * dst,size_t size)57 inet_ntop(int af, const void *src, char *dst, size_t size)
58 {
59 switch (af) {
60 case AF_INET:
61 return (inet_ntop4(src, dst, size));
62 case AF_INET6:
63 return (inet_ntop6(src, dst, size));
64 default:
65 errno = EAFNOSUPPORT;
66 return (NULL);
67 }
68 /* NOTREACHED */
69 }
70
71 /* const char *
72 * inet_ntop4(src, dst, size)
73 * format an IPv4 address, more or less like inet_ntoa()
74 * return:
75 * `dst' (as a const)
76 * notes:
77 * (1) uses no statics
78 * (2) takes a u_char* not an in_addr as input
79 * author:
80 * Paul Vixie, 1996.
81 */
82 static const char *
inet_ntop4(const u_char * src,char * dst,size_t size)83 inet_ntop4(const u_char *src, char *dst, size_t size)
84 {
85 static const char fmt[] = "%u.%u.%u.%u";
86 char tmp[sizeof "255.255.255.255"];
87 int l;
88
89 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]);
90 if (l <= 0 || l >= (int)size) {
91 errno = ENOSPC;
92 return (NULL);
93 }
94 strlcpy(dst, tmp, size);
95 return (dst);
96 }
97
98 /* const char *
99 * inet_ntop6(src, dst, size)
100 * convert IPv6 binary address into presentation (printable) format
101 * author:
102 * Paul Vixie, 1996.
103 */
104 static const char *
inet_ntop6(const u_char * src,char * dst,size_t size)105 inet_ntop6(const u_char *src, char *dst, size_t size)
106 {
107 /*
108 * Note that int32_t and int16_t need only be "at least" large enough
109 * to contain a value of the specified size. On some systems, like
110 * Crays, there is no such thing as an integer variable with 16 bits.
111 * Keep this in mind if you think this function should have been coded
112 * to use pointer overlays. All the world's not a VAX.
113 */
114 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
115 char *tp, *ep;
116 struct { int base, len; } best, cur;
117 u_int words[IN6ADDRSZ / INT16SZ];
118 int i;
119 int advance;
120
121 /*
122 * Preprocess:
123 * Copy the input (bytewise) array into a wordwise array.
124 * Find the longest run of 0x00's in src[] for :: shorthanding.
125 */
126 memset(words, '\0', sizeof words);
127 for (i = 0; i < IN6ADDRSZ; i++)
128 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
129 best.base = -1;
130 cur.base = -1;
131 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
132 if (words[i] == 0) {
133 if (cur.base == -1)
134 cur.base = i, cur.len = 1;
135 else
136 cur.len++;
137 } else {
138 if (cur.base != -1) {
139 if (best.base == -1 || cur.len > best.len)
140 best = cur;
141 cur.base = -1;
142 }
143 }
144 }
145 if (cur.base != -1) {
146 if (best.base == -1 || cur.len > best.len)
147 best = cur;
148 }
149 if (best.base != -1 && best.len < 2)
150 best.base = -1;
151
152 /*
153 * Format the result.
154 */
155 tp = tmp;
156 ep = tmp + sizeof(tmp);
157 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) {
158 /* Are we inside the best run of 0x00's? */
159 if (best.base != -1 && i >= best.base &&
160 i < (best.base + best.len)) {
161 if (i == best.base) {
162 if (tp + 1 >= ep)
163 return (NULL);
164 *tp++ = ':';
165 }
166 continue;
167 }
168 /* Are we following an initial run of 0x00s or any real hex? */
169 if (i != 0) {
170 if (tp + 1 >= ep)
171 return (NULL);
172 *tp++ = ':';
173 }
174 /* Is this address an encapsulated IPv4? */
175 if (i == 6 && best.base == 0 &&
176 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
177 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp)))
178 return (NULL);
179 tp += strlen(tp);
180 break;
181 }
182 advance = snprintf(tp, ep - tp, "%x", words[i]);
183 if (advance <= 0 || advance >= ep - tp)
184 return (NULL);
185 tp += advance;
186 }
187 /* Was it a trailing run of 0x00's? */
188 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) {
189 if (tp + 1 >= ep)
190 return (NULL);
191 *tp++ = ':';
192 }
193 if (tp + 1 >= ep)
194 return (NULL);
195 *tp++ = '\0';
196
197 /*
198 * Check for overflow, copy, and we're done.
199 */
200 if ((size_t)(tp - tmp) > size) {
201 errno = ENOSPC;
202 return (NULL);
203 }
204 strlcpy(dst, tmp, size);
205 return (dst);
206 }
207
208 #endif /* !HAVE_INET_NTOP */
209