Merge branch 'nd/index-pack-l10n-buf-overflow' into maint-1.8.1
[git/jnareb-git.git] / compat / inet_ntop.c
blob90b7cc45f33411bbc39cd731ca3e43288cb40b69
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 "../git-compat-util.h"
20 #ifndef NS_INADDRSZ
21 #define NS_INADDRSZ 4
22 #endif
23 #ifndef NS_IN6ADDRSZ
24 #define NS_IN6ADDRSZ 16
25 #endif
26 #ifndef NS_INT16SZ
27 #define NS_INT16SZ 2
28 #endif
31 * WARNING: Don't even consider trying to compile this on a system where
32 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
35 /* const char *
36 * inet_ntop4(src, dst, size)
37 * format an IPv4 address
38 * return:
39 * `dst' (as a const)
40 * notes:
41 * (1) uses no statics
42 * (2) takes a u_char* not an in_addr as input
43 * author:
44 * Paul Vixie, 1996.
46 static const char *
47 inet_ntop4(const u_char *src, char *dst, size_t size)
49 static const char fmt[] = "%u.%u.%u.%u";
50 char tmp[sizeof "255.255.255.255"];
51 int nprinted;
53 nprinted = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
54 if (nprinted < 0)
55 return (NULL); /* we assume "errno" was set by "snprintf()" */
56 if ((size_t)nprinted > size) {
57 errno = ENOSPC;
58 return (NULL);
60 strcpy(dst, tmp);
61 return (dst);
64 #ifndef NO_IPV6
65 /* const char *
66 * inet_ntop6(src, dst, size)
67 * convert IPv6 binary address into presentation (printable) format
68 * author:
69 * Paul Vixie, 1996.
71 static const char *
72 inet_ntop6(const u_char *src, char *dst, size_t size)
75 * Note that int32_t and int16_t need only be "at least" large enough
76 * to contain a value of the specified size. On some systems, like
77 * Crays, there is no such thing as an integer variable with 16 bits.
78 * Keep this in mind if you think this function should have been coded
79 * to use pointer overlays. All the world's not a VAX.
81 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
82 struct { int base, len; } best, cur;
83 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
84 int i;
87 * Preprocess:
88 * Copy the input (bytewise) array into a wordwise array.
89 * Find the longest run of 0x00's in src[] for :: shorthanding.
91 memset(words, '\0', sizeof words);
92 for (i = 0; i < NS_IN6ADDRSZ; i++)
93 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
94 best.base = -1;
95 best.len = 0;
96 cur.base = -1;
97 cur.len = 0;
98 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
99 if (words[i] == 0) {
100 if (cur.base == -1)
101 cur.base = i, cur.len = 1;
102 else
103 cur.len++;
104 } else {
105 if (cur.base != -1) {
106 if (best.base == -1 || cur.len > best.len)
107 best = cur;
108 cur.base = -1;
112 if (cur.base != -1) {
113 if (best.base == -1 || cur.len > best.len)
114 best = cur;
116 if (best.base != -1 && best.len < 2)
117 best.base = -1;
120 * Format the result.
122 tp = tmp;
123 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
124 /* Are we inside the best run of 0x00's? */
125 if (best.base != -1 && i >= best.base &&
126 i < (best.base + best.len)) {
127 if (i == best.base)
128 *tp++ = ':';
129 continue;
131 /* Are we following an initial run of 0x00s or any real hex? */
132 if (i != 0)
133 *tp++ = ':';
134 /* Is this address an encapsulated IPv4? */
135 if (i == 6 && best.base == 0 &&
136 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
137 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
138 return (NULL);
139 tp += strlen(tp);
140 break;
142 tp += snprintf(tp, sizeof tmp - (tp - tmp), "%x", words[i]);
144 /* Was it a trailing run of 0x00's? */
145 if (best.base != -1 && (best.base + best.len) ==
146 (NS_IN6ADDRSZ / NS_INT16SZ))
147 *tp++ = ':';
148 *tp++ = '\0';
151 * Check for overflow, copy, and we're done.
153 if ((size_t)(tp - tmp) > size) {
154 errno = ENOSPC;
155 return (NULL);
157 strcpy(dst, tmp);
158 return (dst);
160 #endif
162 /* char *
163 * inet_ntop(af, src, dst, size)
164 * convert a network format address to presentation format.
165 * return:
166 * pointer to presentation format address (`dst'), or NULL (see errno).
167 * author:
168 * Paul Vixie, 1996.
170 const char *
171 inet_ntop(int af, const void *src, char *dst, size_t size)
173 switch (af) {
174 case AF_INET:
175 return (inet_ntop4(src, dst, size));
176 #ifndef NO_IPV6
177 case AF_INET6:
178 return (inet_ntop6(src, dst, size));
179 #endif
180 default:
181 errno = EAFNOSUPPORT;
182 return (NULL);
184 /* NOTREACHED */