Fix a bunch of pointer declarations (codestyle)
[git/git.git] / compat / inet_ntop.c
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1/*
2 * Copyright (c) 1996-1999 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#include <errno.h>
19#include <sys/types.h>
20#include <sys/socket.h>
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21#include <netinet/in.h>
22#include <arpa/inet.h>
23#include <stdio.h>
24#include <string.h>
25
26#ifndef NS_INADDRSZ
27#define NS_INADDRSZ 4
28#endif
29#ifndef NS_IN6ADDRSZ
30#define NS_IN6ADDRSZ 16
31#endif
32#ifndef NS_INT16SZ
33#define NS_INT16SZ 2
34#endif
35
36/*
37 * WARNING: Don't even consider trying to compile this on a system where
38 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
39 */
40
41/* const char *
42 * inet_ntop4(src, dst, size)
43 * format an IPv4 address
44 * return:
45 * `dst' (as a const)
46 * notes:
47 * (1) uses no statics
48 * (2) takes a u_char* not an in_addr as input
49 * author:
50 * Paul Vixie, 1996.
51 */
52static const char *
53inet_ntop4(src, dst, size)
54 const u_char *src;
55 char *dst;
56 size_t size;
57{
58 static const char fmt[] = "%u.%u.%u.%u";
59 char tmp[sizeof "255.255.255.255"];
60 int nprinted;
61
62 nprinted = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
63 if (nprinted < 0)
64 return (NULL); /* we assume "errno" was set by "snprintf()" */
65 if ((size_t)nprinted > size) {
66 errno = ENOSPC;
67 return (NULL);
68 }
69 strcpy(dst, tmp);
70 return (dst);
71}
72
73#ifndef NO_IPV6
74/* const char *
75 * inet_ntop6(src, dst, size)
76 * convert IPv6 binary address into presentation (printable) format
77 * author:
78 * Paul Vixie, 1996.
79 */
80static const char *
81inet_ntop6(src, dst, size)
82 const u_char *src;
83 char *dst;
84 size_t size;
85{
86 /*
87 * Note that int32_t and int16_t need only be "at least" large enough
88 * to contain a value of the specified size. On some systems, like
89 * Crays, there is no such thing as an integer variable with 16 bits.
90 * Keep this in mind if you think this function should have been coded
91 * to use pointer overlays. All the world's not a VAX.
92 */
93 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
94 struct { int base, len; } best, cur;
1d182bd5 95 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
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96 int i;
97
98 /*
99 * Preprocess:
100 * Copy the input (bytewise) array into a wordwise array.
101 * Find the longest run of 0x00's in src[] for :: shorthanding.
102 */
103 memset(words, '\0', sizeof words);
104 for (i = 0; i < NS_IN6ADDRSZ; i++)
105 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
106 best.base = -1;
107 cur.base = -1;
108 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
109 if (words[i] == 0) {
110 if (cur.base == -1)
111 cur.base = i, cur.len = 1;
112 else
113 cur.len++;
114 } else {
115 if (cur.base != -1) {
116 if (best.base == -1 || cur.len > best.len)
117 best = cur;
118 cur.base = -1;
119 }
120 }
121 }
122 if (cur.base != -1) {
123 if (best.base == -1 || cur.len > best.len)
124 best = cur;
125 }
126 if (best.base != -1 && best.len < 2)
127 best.base = -1;
128
129 /*
130 * Format the result.
131 */
132 tp = tmp;
133 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
134 /* Are we inside the best run of 0x00's? */
135 if (best.base != -1 && i >= best.base &&
136 i < (best.base + best.len)) {
137 if (i == best.base)
138 *tp++ = ':';
139 continue;
140 }
141 /* Are we following an initial run of 0x00s or any real hex? */
142 if (i != 0)
143 *tp++ = ':';
144 /* Is this address an encapsulated IPv4? */
145 if (i == 6 && best.base == 0 &&
146 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
147 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
148 return (NULL);
149 tp += strlen(tp);
150 break;
151 }
152 tp += snprintf(tp, sizeof tmp - (tp - tmp), "%x", words[i]);
153 }
154 /* Was it a trailing run of 0x00's? */
155 if (best.base != -1 && (best.base + best.len) ==
156 (NS_IN6ADDRSZ / NS_INT16SZ))
157 *tp++ = ':';
158 *tp++ = '\0';
159
160 /*
161 * Check for overflow, copy, and we're done.
162 */
163 if ((size_t)(tp - tmp) > size) {
164 errno = ENOSPC;
165 return (NULL);
166 }
167 strcpy(dst, tmp);
168 return (dst);
169}
170#endif
171
172/* char *
173 * inet_ntop(af, src, dst, size)
174 * convert a network format address to presentation format.
175 * return:
176 * pointer to presentation format address (`dst'), or NULL (see errno).
177 * author:
178 * Paul Vixie, 1996.
179 */
180const char *
181inet_ntop(af, src, dst, size)
182 int af;
183 const void *src;
184 char *dst;
185 size_t size;
186{
187 switch (af) {
188 case AF_INET:
189 return (inet_ntop4(src, dst, size));
190#ifndef NO_IPV6
191 case AF_INET6:
192 return (inet_ntop6(src, dst, size));
193#endif
194 default:
195 errno = EAFNOSUPPORT;
196 return (NULL);
197 }
198 /* NOTREACHED */
199}