Initial bulk commit for "Git on MSys"
[msysgit/historical-msysgit.git] / git / compat / inet_ntop.c
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1 /*
2 * Copyright (c) 1996-1999 by Internet Software Consortium.
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.
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.
18 #include <errno.h>
19 #include <sys/types.h>
20 #include <sys/socket.h>
21 #include <sys/socket.h>
22 #include <netinet/in.h>
23 #include <arpa/inet.h>
24 #include <stdio.h>
25 #include <string.h>
27 #ifndef NS_INADDRSZ
28 #define NS_INADDRSZ 4
29 #endif
30 #ifndef NS_IN6ADDRSZ
31 #define NS_IN6ADDRSZ 16
32 #endif
33 #ifndef NS_INT16SZ
34 #define NS_INT16SZ 2
35 #endif
38 * WARNING: Don't even consider trying to compile this on a system where
39 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
42 /* const char *
43 * inet_ntop4(src, dst, size)
44 * format an IPv4 address
45 * return:
46 * `dst' (as a const)
47 * notes:
48 * (1) uses no statics
49 * (2) takes a u_char* not an in_addr as input
50 * author:
51 * Paul Vixie, 1996.
53 static const char *
54 inet_ntop4(src, dst, size)
55 const u_char *src;
56 char *dst;
57 size_t size;
59 static const char fmt[] = "%u.%u.%u.%u";
60 char tmp[sizeof "255.255.255.255"];
61 int nprinted;
63 nprinted = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
64 if (nprinted < 0)
65 return (NULL); /* we assume "errno" was set by "snprintf()" */
66 if ((size_t)nprinted > size) {
67 errno = ENOSPC;
68 return (NULL);
70 strcpy(dst, tmp);
71 return (dst);
74 #ifndef NO_IPV6
75 /* const char *
76 * inet_ntop6(src, dst, size)
77 * convert IPv6 binary address into presentation (printable) format
78 * author:
79 * Paul Vixie, 1996.
81 static const char *
82 inet_ntop6(src, dst, size)
83 const u_char *src;
84 char *dst;
85 size_t size;
88 * Note that int32_t and int16_t need only be "at least" large enough
89 * to contain a value of the specified size. On some systems, like
90 * Crays, there is no such thing as an integer variable with 16 bits.
91 * Keep this in mind if you think this function should have been coded
92 * to use pointer overlays. All the world's not a VAX.
94 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
95 struct { int base, len; } best, cur;
96 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
97 int i;
100 * Preprocess:
101 * Copy the input (bytewise) array into a wordwise array.
102 * Find the longest run of 0x00's in src[] for :: shorthanding.
104 memset(words, '\0', sizeof words);
105 for (i = 0; i < NS_IN6ADDRSZ; i++)
106 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
107 best.base = -1;
108 cur.base = -1;
109 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
110 if (words[i] == 0) {
111 if (cur.base == -1)
112 cur.base = i, cur.len = 1;
113 else
114 cur.len++;
115 } else {
116 if (cur.base != -1) {
117 if (best.base == -1 || cur.len > best.len)
118 best = cur;
119 cur.base = -1;
123 if (cur.base != -1) {
124 if (best.base == -1 || cur.len > best.len)
125 best = cur;
127 if (best.base != -1 && best.len < 2)
128 best.base = -1;
131 * Format the result.
133 tp = tmp;
134 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
135 /* Are we inside the best run of 0x00's? */
136 if (best.base != -1 && i >= best.base &&
137 i < (best.base + best.len)) {
138 if (i == best.base)
139 *tp++ = ':';
140 continue;
142 /* Are we following an initial run of 0x00s or any real hex? */
143 if (i != 0)
144 *tp++ = ':';
145 /* Is this address an encapsulated IPv4? */
146 if (i == 6 && best.base == 0 &&
147 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
148 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
149 return (NULL);
150 tp += strlen(tp);
151 break;
153 tp += snprintf(tp, sizeof tmp - (tp - tmp), "%x", words[i]);
155 /* Was it a trailing run of 0x00's? */
156 if (best.base != -1 && (best.base + best.len) ==
157 (NS_IN6ADDRSZ / NS_INT16SZ))
158 *tp++ = ':';
159 *tp++ = '\0';
162 * Check for overflow, copy, and we're done.
164 if ((size_t)(tp - tmp) > size) {
165 errno = ENOSPC;
166 return (NULL);
168 strcpy(dst, tmp);
169 return (dst);
171 #endif
173 /* char *
174 * inet_ntop(af, src, dst, size)
175 * convert a network format address to presentation format.
176 * return:
177 * pointer to presentation format address (`dst'), or NULL (see errno).
178 * author:
179 * Paul Vixie, 1996.
181 const char *
182 inet_ntop(af, src, dst, size)
183 int af;
184 const void *src;
185 char *dst;
186 size_t size;
188 switch (af) {
189 case AF_INET:
190 return (inet_ntop4(src, dst, size));
191 #ifndef NO_IPV6
192 case AF_INET6:
193 return (inet_ntop6(src, dst, size));
194 #endif
195 default:
196 errno = EAFNOSUPPORT;
197 return (NULL);
199 /* NOTREACHED */