1 | /* |
2 | * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") |
3 | * Copyright (c) 1996-1999 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 ISC DISCLAIMS ALL WARRANTIES |
10 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
11 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR |
12 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
13 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
14 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
15 | * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
16 | */ |
17 | |
18 | #if defined(LIBC_SCCS) && !defined(lint) |
19 | static const char rcsid[] = "$Id: inet_ntop.c,v 1.3.18.2 2005/11/03 23:02:22 marka Exp $" ; |
20 | #endif /* LIBC_SCCS and not lint */ |
21 | |
22 | #include <sys/param.h> |
23 | #include <sys/socket.h> |
24 | #include <sys/systm.h> |
25 | |
26 | #include <netinet/in.h> |
27 | |
28 | /*% |
29 | * WARNING: Don't even consider trying to compile this on a system where |
30 | * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. |
31 | */ |
32 | |
33 | static char *inet_ntop4(const u_char *src, char *dst, socklen_t size); |
34 | static char *inet_ntop6(const u_char *src, char *dst, socklen_t size); |
35 | |
36 | /* char * |
37 | * inet_ntop(af, src, dst, size) |
38 | * convert a network format address to presentation format. |
39 | * return: |
40 | * pointer to presentation format address (`dst'), or NULL (see errno). |
41 | * author: |
42 | * Paul Vixie, 1996. |
43 | */ |
44 | const char * |
45 | inet_ntop(int af, const void *src, char *dst, socklen_t size) |
46 | { |
47 | switch (af) { |
48 | case AF_INET: |
49 | return inet_ntop4(src, dst, size); |
50 | case AF_INET6: |
51 | return inet_ntop6(src, dst, size); |
52 | default: |
53 | return NULL; |
54 | } |
55 | /* NOTREACHED */ |
56 | } |
57 | |
58 | /* const char * |
59 | * inet_ntop4(src, dst, size) |
60 | * format an IPv4 address |
61 | * return: |
62 | * `dst' (as a const) |
63 | * notes: |
64 | * (1) uses no statics |
65 | * (2) takes a u_char* not an in_addr as input |
66 | * author: |
67 | * Paul Vixie, 1996. |
68 | */ |
69 | static char * |
70 | inet_ntop4(const u_char *src, char *dst, socklen_t size) |
71 | { |
72 | static const char fmt[] = "%u.%u.%u.%u" ; |
73 | char tmp[sizeof "255.255.255.255" ]; |
74 | int l; |
75 | |
76 | l = snprintf(tmp, count: sizeof(tmp), fmt, src[0], src[1], src[2], src[3]); |
77 | if (l <= 0 || (socklen_t) l >= size) { |
78 | return NULL; |
79 | } |
80 | strlcpy(dst, src: tmp, n: size); |
81 | return dst; |
82 | } |
83 | |
84 | /* const char * |
85 | * inet_ntop6(src, dst, size) |
86 | * convert IPv6 binary address into presentation (printable) format |
87 | * author: |
88 | * Paul Vixie, 1996. |
89 | */ |
90 | static char * |
91 | inet_ntop6(const u_char *src, char *dst, socklen_t size) |
92 | { |
93 | /* |
94 | * Note that int32_t and int16_t need only be "at least" large enough |
95 | * to contain a value of the specified size. On some systems, like |
96 | * Crays, there is no such thing as an integer variable with 16 bits. |
97 | * Keep this in mind if you think this function should have been coded |
98 | * to use pointer overlays. All the world's not a VAX. |
99 | */ |
100 | char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255" ], *tp; |
101 | struct { int base, len; } best, cur; |
102 | #define NS_IN6ADDRSZ 16 |
103 | #define NS_INT16SZ 2 |
104 | u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; |
105 | int i; |
106 | |
107 | /* |
108 | * Preprocess: |
109 | * Copy the input (bytewise) array into a wordwise array. |
110 | * Find the longest run of 0x00's in src[] for :: shorthanding. |
111 | */ |
112 | memset(s: words, c: '\0', n: sizeof words); |
113 | for (i = 0; i < NS_IN6ADDRSZ; i++) { |
114 | words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); |
115 | } |
116 | best.base = -1; |
117 | best.len = 0; |
118 | cur.base = -1; |
119 | cur.len = 0; |
120 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { |
121 | if (words[i] == 0) { |
122 | if (cur.base == -1) { |
123 | cur.base = i; |
124 | cur.len = 1; |
125 | } else { |
126 | cur.len++; |
127 | } |
128 | } else { |
129 | if (cur.base != -1) { |
130 | if (best.base == -1 || cur.len > best.len) { |
131 | best = cur; |
132 | } |
133 | cur.base = -1; |
134 | } |
135 | } |
136 | } |
137 | if (cur.base != -1) { |
138 | if (best.base == -1 || cur.len > best.len) { |
139 | best = cur; |
140 | } |
141 | } |
142 | if (best.base != -1 && best.len < 2) { |
143 | best.base = -1; |
144 | } |
145 | |
146 | /* |
147 | * Format the result. |
148 | */ |
149 | tp = tmp; |
150 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { |
151 | /* Are we inside the best run of 0x00's? */ |
152 | if (best.base != -1 && i >= best.base && |
153 | i < (best.base + best.len)) { |
154 | if (i == best.base) { |
155 | *tp++ = ':'; |
156 | } |
157 | continue; |
158 | } |
159 | /* Are we following an initial run of 0x00s or any real hex? */ |
160 | if (i != 0) { |
161 | *tp++ = ':'; |
162 | } |
163 | /* Is this address an encapsulated IPv4? */ |
164 | if (i == 6 && best.base == 0 && (best.len == 6 || |
165 | (best.len == 7 && words[7] != 0x0001) || |
166 | (best.len == 5 && words[5] == 0xffff))) { |
167 | if (!inet_ntop4(src: src + 12, dst: tp, |
168 | size: (socklen_t)(sizeof tmp - (tp - tmp)))) { |
169 | return NULL; |
170 | } |
171 | tp += strlen(s: tp); |
172 | break; |
173 | } |
174 | tp += scnprintf(tp, count: sizeof(tmp), "%x" , words[i]); |
175 | } |
176 | /* Was it a trailing run of 0x00's? */ |
177 | if (best.base != -1 && (best.base + best.len) == |
178 | (NS_IN6ADDRSZ / NS_INT16SZ)) { |
179 | *tp++ = ':'; |
180 | } |
181 | *tp++ = '\0'; |
182 | |
183 | /* |
184 | * Check for overflow, copy, and we're done. |
185 | */ |
186 | if ((socklen_t)(tp - tmp) > size) { |
187 | return NULL; |
188 | } |
189 | strlcpy(dst, src: tmp, n: size); |
190 | return dst; |
191 | } |
192 | |
193 | /*! \file */ |
194 | |