1 /* from NetBSD: inet_ntop.c,v 1.9 2000/01/22 22:19:16 mycroft Exp */
2
3 /* Copyright (c) 1996 by Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
10 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
11 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
12 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
13 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
14 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
15 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
16 * SOFTWARE.
17 */
18
19 #ifndef IN6ADDRSZ
20 #define IN6ADDRSZ 16
21 #endif
22
23 #ifndef INT16SZ
24 #define INT16SZ 2
25 #endif
26
27 #ifdef SPRINTF_CHAR
28 # define SPRINTF(x) strlen(sprintf/**/x)
29 #else
30 # define SPRINTF(x) ((socklen_t)sprintf x)
31 #endif
32
33 /*
34 * WARNING: Don't even consider trying to compile this on a system where
35 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
36 */
37
38 static const char *inet_ntop4(const u_char *src, char *dst, socklen_t size);
39
40 #ifdef INET6
41 static const char *inet_ntop6(const u_char *src, char *dst, socklen_t size);
42 #endif
43
44 /* char *
45 * inet_ntop(af, src, dst, size)
46 * convert a network format address to presentation format.
47 * return:
48 * pointer to presentation format address (`dst'), or NULL (see errno).
49 * author:
50 * Paul Vixie, 1996.
51 */
52 PCSTR
53 WSAAPI
inet_ntop(_In_ INT af,_In_ const VOID * src,_Out_writes_ (StringBufSize)PSTR dst,_In_ size_t size)54 inet_ntop(
55 _In_ INT af,
56 _In_ const VOID *src,
57 _Out_writes_(StringBufSize) PSTR dst,
58 _In_ size_t size)
59 {
60
61 switch (af) {
62 case AF_INET:
63 return (inet_ntop4(src, dst, size));
64 #ifdef INET6
65 case AF_INET6:
66 return (inet_ntop6(src, dst, size));
67 #endif
68 default:
69 WSASetLastError(WSAEAFNOSUPPORT);
70 return (NULL);
71 }
72 /* NOTREACHED */
73 }
74
75 /* const char *
76 * inet_ntop4(src, dst, size)
77 * format an IPv4 address, more or less like inet_ntoa()
78 * return:
79 * `dst' (as a const)
80 * notes:
81 * (1) uses no statics
82 * (2) takes a u_char* not an in_addr as input
83 * author:
84 * Paul Vixie, 1996.
85 */
86 static const char *
inet_ntop4(const u_char * src,char * dst,socklen_t size)87 inet_ntop4(const u_char *src, char *dst, socklen_t size)
88 {
89 static const char fmt[] = "%u.%u.%u.%u";
90 char tmp[sizeof "255.255.255.255"];
91
92 if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) {
93 WSASetLastError(WSAEINVAL);
94 return (NULL);
95 }
96 strcpy(dst, tmp);
97 return (dst);
98 }
99
100 #ifdef INET6
101 /* const char *
102 * inet_ntop6(src, dst, size)
103 * convert IPv6 binary address into presentation (printable) format
104 * author:
105 * Paul Vixie, 1996.
106 */
107 static const char *
inet_ntop6(const u_char * src,char * dst,socklen_t size)108 inet_ntop6(const u_char *src, char *dst, socklen_t size)
109 {
110 /*
111 * Note that int32_t and int16_t need only be "at least" large enough
112 * to contain a value of the specified size. On some systems, like
113 * Crays, there is no such thing as an integer variable with 16 bits.
114 * Keep this in mind if you think this function should have been coded
115 * to use pointer overlays. All the world's not a VAX.
116 */
117 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
118 struct { int base, len; } best, cur;
119 u_int words[IN6ADDRSZ / INT16SZ];
120 int i;
121
122 /*
123 * Preprocess:
124 * Copy the input (bytewise) array into a wordwise array.
125 * Find the longest run of 0x00's in src[] for :: shorthanding.
126 */
127 memset(words, '\0', sizeof words);
128 for (i = 0; i < IN6ADDRSZ; i++)
129 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
130 best.base = -1;
131 cur.base = -1;
132 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
133 if (words[i] == 0) {
134 if (cur.base == -1)
135 cur.base = i, cur.len = 1;
136 else
137 cur.len++;
138 } else {
139 if (cur.base != -1) {
140 if (best.base == -1 || cur.len > best.len)
141 best = cur;
142 cur.base = -1;
143 }
144 }
145 }
146 if (cur.base != -1) {
147 if (best.base == -1 || cur.len > best.len)
148 best = cur;
149 }
150 if (best.base != -1 && best.len < 2)
151 best.base = -1;
152
153 /*
154 * Format the result.
155 */
156 tp = tmp;
157 for (i = 0; i < (IN6ADDRSZ / INT16SZ); 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 *tp++ = ':';
163 continue;
164 }
165 /* Are we following an initial run of 0x00s or any real hex? */
166 if (i != 0)
167 *tp++ = ':';
168 /* Is this address an encapsulated IPv4? */
169 if (i == 6 && best.base == 0 &&
170 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
171 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
172 return (NULL);
173 tp += strlen(tp);
174 break;
175 }
176 tp += SPRINTF((tp, "%x", words[i]));
177 }
178 /* Was it a trailing run of 0x00's? */
179 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
180 *tp++ = ':';
181 *tp++ = '\0';
182
183 /*
184 * Check for overflow, copy, and we're done.
185 */
186 if ((socklen_t)(tp - tmp) > size) {
187 WSASetLastError(WSAEINVAL);
188 return (NULL);
189 }
190 strcpy(dst, tmp);
191 return (dst);
192 }
193 #endif
194
195