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 #ifdef HAVE_SYS_SOCKET_H
27 #include <sys/socket.h>
28 #endif
29 #ifdef HAVE_NETINET_IN_H
30 #include <netinet/in.h>
31 #endif
32 #include <string.h>
33 #include <errno.h>
34 #include <stdio.h>
35
36 #ifndef IN6ADDRSZ
37 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */
38 #endif
39
40 #ifndef INT16SZ
41 #define INT16SZ 2 /* for systems without 16-bit ints */
42 #endif
43
44 /*
45 * WARNING: Don't even consider trying to compile this on a system where
46 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
47 */
48
49 static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
50 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
51
52 /* char *
53 * inet_ntop(af, src, dst, size)
54 * convert a network format address to presentation format.
55 * return:
56 * pointer to presentation format address (`dst'), or NULL (see errno).
57 * author:
58 * Paul Vixie, 1996.
59 */
60 const char *
inet_ntop(int af,const void * src,char * dst,size_t size)61 inet_ntop(int af, const void *src, char *dst, size_t size)
62 {
63 switch (af) {
64 case AF_INET:
65 return (inet_ntop4(src, dst, size));
66 case AF_INET6:
67 return (inet_ntop6(src, dst, size));
68 default:
69 #ifdef EAFNOSUPPORT
70 errno = EAFNOSUPPORT;
71 #else
72 errno = ENOSYS;
73 #endif
74 return (NULL);
75 }
76 /* NOTREACHED */
77 }
78
79 /* const char *
80 * inet_ntop4(src, dst, size)
81 * format an IPv4 address, more or less like inet_ntoa()
82 * return:
83 * `dst' (as a const)
84 * notes:
85 * (1) uses no statics
86 * (2) takes a u_char* not an in_addr as input
87 * author:
88 * Paul Vixie, 1996.
89 */
90 static const char *
inet_ntop4(const u_char * src,char * dst,size_t size)91 inet_ntop4(const u_char *src, char *dst, size_t size)
92 {
93 static const char fmt[] = "%u.%u.%u.%u";
94 char tmp[sizeof "255.255.255.255"];
95 int l;
96
97 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]);
98 if (l <= 0 || l >= (int)size) {
99 errno = ENOSPC;
100 return (NULL);
101 }
102 strlcpy(dst, tmp, size);
103 return (dst);
104 }
105
106 /* const char *
107 * inet_ntop6(src, dst, size)
108 * convert IPv6 binary address into presentation (printable) format
109 * author:
110 * Paul Vixie, 1996.
111 */
112 static const char *
inet_ntop6(const u_char * src,char * dst,size_t size)113 inet_ntop6(const u_char *src, char *dst, size_t size)
114 {
115 /*
116 * Note that int32_t and int16_t need only be "at least" large enough
117 * to contain a value of the specified size. On some systems, like
118 * Crays, there is no such thing as an integer variable with 16 bits.
119 * Keep this in mind if you think this function should have been coded
120 * to use pointer overlays. All the world's not a VAX.
121 */
122 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
123 char *tp, *ep;
124 struct { int base, len; } best, cur;
125 u_int words[IN6ADDRSZ / INT16SZ];
126 int i;
127 int advance;
128
129 /*
130 * Preprocess:
131 * Copy the input (bytewise) array into a wordwise array.
132 * Find the longest run of 0x00's in src[] for :: shorthanding.
133 */
134 memset(words, '\0', sizeof words);
135 for (i = 0; i < IN6ADDRSZ; i++)
136 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
137 best.base = -1;
138 best.len = 0;
139 cur.base = -1;
140 cur.len = 0;
141 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
142 if (words[i] == 0) {
143 if (cur.base == -1)
144 cur.base = i, cur.len = 1;
145 else
146 cur.len++;
147 } else {
148 if (cur.base != -1) {
149 if (best.base == -1 || cur.len > best.len)
150 best = cur;
151 cur.base = -1;
152 }
153 }
154 }
155 if (cur.base != -1) {
156 if (best.base == -1 || cur.len > best.len)
157 best = cur;
158 }
159 if (best.base != -1 && best.len < 2)
160 best.base = -1;
161
162 /*
163 * Format the result.
164 */
165 tp = tmp;
166 ep = tmp + sizeof(tmp);
167 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) {
168 /* Are we inside the best run of 0x00's? */
169 if (best.base != -1 && i >= best.base &&
170 i < (best.base + best.len)) {
171 if (i == best.base) {
172 if (tp + 1 >= ep)
173 return (NULL);
174 *tp++ = ':';
175 }
176 continue;
177 }
178 /* Are we following an initial run of 0x00s or any real hex? */
179 if (i != 0) {
180 if (tp + 1 >= ep)
181 return (NULL);
182 *tp++ = ':';
183 }
184 /* Is this address an encapsulated IPv4? */
185 if (i == 6 && best.base == 0 &&
186 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
187 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp)))
188 return (NULL);
189 tp += strlen(tp);
190 break;
191 }
192 advance = snprintf(tp, ep - tp, "%x", words[i]);
193 if (advance <= 0 || advance >= ep - tp)
194 return (NULL);
195 tp += advance;
196 }
197 /* Was it a trailing run of 0x00's? */
198 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) {
199 if (tp + 1 >= ep)
200 return (NULL);
201 *tp++ = ':';
202 }
203 if (tp + 1 >= ep)
204 return (NULL);
205 *tp++ = '\0';
206
207 /*
208 * Check for overflow, copy, and we're done.
209 */
210 if ((size_t)(tp - tmp) > size) {
211 errno = ENOSPC;
212 return (NULL);
213 }
214 strlcpy(dst, tmp, size);
215 return (dst);
216 }
217
218 #endif /* !HAVE_INET_NTOP */
219