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 <sys/param.h> |
19 | #include <sys/types.h> |
20 | #include <sys/socket.h> |
21 | |
22 | #include <netinet/in.h> |
23 | #include <arpa/inet.h> |
24 | #include <arpa/nameser.h> |
25 | |
26 | #include <errno.h> |
27 | #include <stdio.h> |
28 | #include <string.h> |
29 | |
30 | #ifdef SPRINTF_CHAR |
31 | # define SPRINTF(x) strlen(sprintf/**/x) |
32 | #else |
33 | # define SPRINTF(x) ((size_t)sprintf x) |
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 | static const char *inet_ntop4 (const u_char *src, char *dst, socklen_t size) |
42 | internal_function; |
43 | static const char *inet_ntop6 (const u_char *src, char *dst, socklen_t size) |
44 | internal_function; |
45 | |
46 | /* char * |
47 | * inet_ntop(af, src, dst, size) |
48 | * convert a network format address to presentation format. |
49 | * return: |
50 | * pointer to presentation format address (`dst'), or NULL (see errno). |
51 | * author: |
52 | * Paul Vixie, 1996. |
53 | */ |
54 | const char * |
55 | inet_ntop (int af, const void *src, char *dst, socklen_t size) |
56 | { |
57 | switch (af) { |
58 | case AF_INET: |
59 | return (inet_ntop4(src, dst, size)); |
60 | case AF_INET6: |
61 | return (inet_ntop6(src, dst, size)); |
62 | default: |
63 | __set_errno (EAFNOSUPPORT); |
64 | return (NULL); |
65 | } |
66 | /* NOTREACHED */ |
67 | } |
68 | libc_hidden_def (inet_ntop) |
69 | |
70 | /* const char * |
71 | * inet_ntop4(src, dst, size) |
72 | * format an IPv4 address |
73 | * return: |
74 | * `dst' (as a const) |
75 | * notes: |
76 | * (1) uses no statics |
77 | * (2) takes a u_char* not an in_addr as input |
78 | * author: |
79 | * Paul Vixie, 1996. |
80 | */ |
81 | static const char * |
82 | internal_function |
83 | inet_ntop4 (const u_char *src, char *dst, socklen_t size) |
84 | { |
85 | static const char fmt[] = "%u.%u.%u.%u" ; |
86 | char tmp[sizeof "255.255.255.255" ]; |
87 | |
88 | if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) >= size) { |
89 | __set_errno (ENOSPC); |
90 | return (NULL); |
91 | } |
92 | return strcpy(dst, tmp); |
93 | } |
94 | |
95 | /* const char * |
96 | * inet_ntop6(src, dst, size) |
97 | * convert IPv6 binary address into presentation (printable) format |
98 | * author: |
99 | * Paul Vixie, 1996. |
100 | */ |
101 | static const char * |
102 | internal_function |
103 | inet_ntop6 (const u_char *src, char *dst, socklen_t size) |
104 | { |
105 | /* |
106 | * Note that int32_t and int16_t need only be "at least" large enough |
107 | * to contain a value of the specified size. On some systems, like |
108 | * Crays, there is no such thing as an integer variable with 16 bits. |
109 | * Keep this in mind if you think this function should have been coded |
110 | * to use pointer overlays. All the world's not a VAX. |
111 | */ |
112 | char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255" ], *tp; |
113 | struct { int base, len; } best, cur; |
114 | u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; |
115 | int i; |
116 | |
117 | /* |
118 | * Preprocess: |
119 | * Copy the input (bytewise) array into a wordwise array. |
120 | * Find the longest run of 0x00's in src[] for :: shorthanding. |
121 | */ |
122 | memset(words, '\0', sizeof words); |
123 | for (i = 0; i < NS_IN6ADDRSZ; i += 2) |
124 | words[i / 2] = (src[i] << 8) | src[i + 1]; |
125 | best.base = -1; |
126 | cur.base = -1; |
127 | best.len = 0; |
128 | cur.len = 0; |
129 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { |
130 | if (words[i] == 0) { |
131 | if (cur.base == -1) |
132 | cur.base = i, cur.len = 1; |
133 | else |
134 | cur.len++; |
135 | } else { |
136 | if (cur.base != -1) { |
137 | if (best.base == -1 || cur.len > best.len) |
138 | best = cur; |
139 | cur.base = -1; |
140 | } |
141 | } |
142 | } |
143 | if (cur.base != -1) { |
144 | if (best.base == -1 || cur.len > best.len) |
145 | best = cur; |
146 | } |
147 | if (best.base != -1 && best.len < 2) |
148 | best.base = -1; |
149 | |
150 | /* |
151 | * Format the result. |
152 | */ |
153 | tp = tmp; |
154 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { |
155 | /* Are we inside the best run of 0x00's? */ |
156 | if (best.base != -1 && i >= best.base && |
157 | i < (best.base + best.len)) { |
158 | if (i == best.base) |
159 | *tp++ = ':'; |
160 | continue; |
161 | } |
162 | /* Are we following an initial run of 0x00s or any real hex? */ |
163 | if (i != 0) |
164 | *tp++ = ':'; |
165 | /* Is this address an encapsulated IPv4? */ |
166 | if (i == 6 && best.base == 0 && |
167 | (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { |
168 | if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) |
169 | return (NULL); |
170 | tp += strlen(tp); |
171 | break; |
172 | } |
173 | tp += SPRINTF((tp, "%x" , words[i])); |
174 | } |
175 | /* Was it a trailing run of 0x00's? */ |
176 | if (best.base != -1 && (best.base + best.len) == |
177 | (NS_IN6ADDRSZ / NS_INT16SZ)) |
178 | *tp++ = ':'; |
179 | *tp++ = '\0'; |
180 | |
181 | /* |
182 | * Check for overflow, copy, and we're done. |
183 | */ |
184 | if ((socklen_t)(tp - tmp) > size) { |
185 | __set_errno (ENOSPC); |
186 | return (NULL); |
187 | } |
188 | return strcpy(dst, tmp); |
189 | } |
190 | |