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 | #if defined(LIBC_SCCS) && !defined(lint) |
19 | static const char rcsid[] = "$BINDId: inet_ntop.c,v 1.8 1999/10/13 16:39:28 vixie Exp $" ; |
20 | #endif /* LIBC_SCCS and not lint */ |
21 | |
22 | #include <sys/param.h> |
23 | #include <sys/types.h> |
24 | #include <sys/socket.h> |
25 | |
26 | #include <netinet/in.h> |
27 | #include <arpa/inet.h> |
28 | #include <arpa/nameser.h> |
29 | |
30 | #include <errno.h> |
31 | #include <stdio.h> |
32 | #include <string.h> |
33 | |
34 | #ifdef SPRINTF_CHAR |
35 | # define SPRINTF(x) strlen(sprintf/**/x) |
36 | #else |
37 | # define SPRINTF(x) ((size_t)sprintf x) |
38 | #endif |
39 | |
40 | /* |
41 | * WARNING: Don't even consider trying to compile this on a system where |
42 | * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. |
43 | */ |
44 | |
45 | static const char *inet_ntop4 (const u_char *src, char *dst, socklen_t size) |
46 | internal_function; |
47 | static const char *inet_ntop6 (const u_char *src, char *dst, socklen_t size) |
48 | internal_function; |
49 | |
50 | /* char * |
51 | * inet_ntop(af, src, dst, size) |
52 | * convert a network format address to presentation format. |
53 | * return: |
54 | * pointer to presentation format address (`dst'), or NULL (see errno). |
55 | * author: |
56 | * Paul Vixie, 1996. |
57 | */ |
58 | const char * |
59 | inet_ntop (int af, const void *src, char *dst, socklen_t size) |
60 | { |
61 | switch (af) { |
62 | case AF_INET: |
63 | return (inet_ntop4(src, dst, size)); |
64 | case AF_INET6: |
65 | return (inet_ntop6(src, dst, size)); |
66 | default: |
67 | __set_errno (EAFNOSUPPORT); |
68 | return (NULL); |
69 | } |
70 | /* NOTREACHED */ |
71 | } |
72 | libc_hidden_def (inet_ntop) |
73 | |
74 | /* const char * |
75 | * inet_ntop4(src, dst, size) |
76 | * format an IPv4 address |
77 | * return: |
78 | * `dst' (as a const) |
79 | * notes: |
80 | * (1) uses no statics |
81 | * (2) takes a u_char* not an in_addr as input |
82 | * author: |
83 | * Paul Vixie, 1996. |
84 | */ |
85 | static const char * |
86 | internal_function |
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 | __set_errno (ENOSPC); |
94 | return (NULL); |
95 | } |
96 | return strcpy(dst, tmp); |
97 | } |
98 | |
99 | /* const char * |
100 | * inet_ntop6(src, dst, size) |
101 | * convert IPv6 binary address into presentation (printable) format |
102 | * author: |
103 | * Paul Vixie, 1996. |
104 | */ |
105 | static const char * |
106 | internal_function |
107 | inet_ntop6 (const u_char *src, char *dst, socklen_t size) |
108 | { |
109 | /* |
110 | * Note that int32_t and int16_t need only be "at least" large enough |
111 | * to contain a value of the specified size. On some systems, like |
112 | * Crays, there is no such thing as an integer variable with 16 bits. |
113 | * Keep this in mind if you think this function should have been coded |
114 | * to use pointer overlays. All the world's not a VAX. |
115 | */ |
116 | char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255" ], *tp; |
117 | struct { int base, len; } best, cur; |
118 | u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; |
119 | int i; |
120 | |
121 | /* |
122 | * Preprocess: |
123 | * Copy the input (bytewise) array into a wordwise array. |
124 | * Find the longest run of 0x00's in src[] for :: shorthanding. |
125 | */ |
126 | memset(words, '\0', sizeof words); |
127 | for (i = 0; i < NS_IN6ADDRSZ; i += 2) |
128 | words[i / 2] = (src[i] << 8) | src[i + 1]; |
129 | best.base = -1; |
130 | cur.base = -1; |
131 | best.len = 0; |
132 | cur.len = 0; |
133 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { |
134 | if (words[i] == 0) { |
135 | if (cur.base == -1) |
136 | cur.base = i, cur.len = 1; |
137 | else |
138 | cur.len++; |
139 | } else { |
140 | if (cur.base != -1) { |
141 | if (best.base == -1 || cur.len > best.len) |
142 | best = cur; |
143 | cur.base = -1; |
144 | } |
145 | } |
146 | } |
147 | if (cur.base != -1) { |
148 | if (best.base == -1 || cur.len > best.len) |
149 | best = cur; |
150 | } |
151 | if (best.base != -1 && best.len < 2) |
152 | best.base = -1; |
153 | |
154 | /* |
155 | * Format the result. |
156 | */ |
157 | tp = tmp; |
158 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { |
159 | /* Are we inside the best run of 0x00's? */ |
160 | if (best.base != -1 && i >= best.base && |
161 | i < (best.base + best.len)) { |
162 | if (i == best.base) |
163 | *tp++ = ':'; |
164 | continue; |
165 | } |
166 | /* Are we following an initial run of 0x00s or any real hex? */ |
167 | if (i != 0) |
168 | *tp++ = ':'; |
169 | /* Is this address an encapsulated IPv4? */ |
170 | if (i == 6 && best.base == 0 && |
171 | (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { |
172 | if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) |
173 | return (NULL); |
174 | tp += strlen(tp); |
175 | break; |
176 | } |
177 | tp += SPRINTF((tp, "%x" , words[i])); |
178 | } |
179 | /* Was it a trailing run of 0x00's? */ |
180 | if (best.base != -1 && (best.base + best.len) == |
181 | (NS_IN6ADDRSZ / NS_INT16SZ)) |
182 | *tp++ = ':'; |
183 | *tp++ = '\0'; |
184 | |
185 | /* |
186 | * Check for overflow, copy, and we're done. |
187 | */ |
188 | if ((socklen_t)(tp - tmp) > size) { |
189 | __set_errno (ENOSPC); |
190 | return (NULL); |
191 | } |
192 | return strcpy(dst, tmp); |
193 | } |
194 | |