FreeBSD/Linux Kernel Cross Reference
sys/rpc/inet_ntop.c
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 $";
20 #endif /* LIBC_SCCS and not lint */
21 #include <sys/cdefs.h>
22 __FBSDID("$FreeBSD: src/sys/rpc/inet_ntop.c,v 1.2 2008/03/28 09:50:32 dfr Exp $");
23
24 #include <sys/param.h>
25 #include <sys/types.h>
26 #include <sys/socket.h>
27 #include <sys/systm.h>
28
29 #include <rpc/types.h>
30 #include <rpc/rpc_com.h>
31
32 /*%
33 * WARNING: Don't even consider trying to compile this on a system where
34 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
35 */
36
37 static const char *inet_ntop4(const u_char *src, char *dst, socklen_t size);
38 static const char *inet_ntop6(const u_char *src, char *dst, socklen_t size);
39
40 /* char *
41 * inet_ntop(af, src, dst, size)
42 * convert a network format address to presentation format.
43 * return:
44 * pointer to presentation format address (`dst'), or NULL (see errno).
45 * author:
46 * Paul Vixie, 1996.
47 */
48 const char *
49 __rpc_inet_ntop(int af, const void * __restrict src, char * __restrict dst,
50 socklen_t size)
51 {
52 switch (af) {
53 case AF_INET:
54 return (inet_ntop4(src, dst, size));
55 case AF_INET6:
56 return (inet_ntop6(src, dst, size));
57 default:
58 return (NULL);
59 }
60 /* NOTREACHED */
61 }
62
63 /* const char *
64 * inet_ntop4(src, dst, size)
65 * format an IPv4 address
66 * return:
67 * `dst' (as a const)
68 * notes:
69 * (1) uses no statics
70 * (2) takes a u_char* not an in_addr as input
71 * author:
72 * Paul Vixie, 1996.
73 */
74 static const char *
75 inet_ntop4(const u_char *src, char *dst, socklen_t size)
76 {
77 static const char fmt[] = "%u.%u.%u.%u";
78 char tmp[sizeof "255.255.255.255"];
79 int l;
80
81 l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
82 if (l <= 0 || (socklen_t) l >= size) {
83 return (NULL);
84 }
85 strlcpy(dst, tmp, size);
86 return (dst);
87 }
88
89 /* const char *
90 * inet_ntop6(src, dst, size)
91 * convert IPv6 binary address into presentation (printable) format
92 * author:
93 * Paul Vixie, 1996.
94 */
95 static const char *
96 inet_ntop6(const u_char *src, char *dst, socklen_t size)
97 {
98 /*
99 * Note that int32_t and int16_t need only be "at least" large enough
100 * to contain a value of the specified size. On some systems, like
101 * Crays, there is no such thing as an integer variable with 16 bits.
102 * Keep this in mind if you think this function should have been coded
103 * to use pointer overlays. All the world's not a VAX.
104 */
105 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
106 struct { int base, len; } best, cur;
107 #define NS_IN6ADDRSZ 16
108 #define NS_INT16SZ 2
109 u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
110 int i;
111
112 /*
113 * Preprocess:
114 * Copy the input (bytewise) array into a wordwise array.
115 * Find the longest run of 0x00's in src[] for :: shorthanding.
116 */
117 memset(words, '\0', sizeof words);
118 for (i = 0; i < NS_IN6ADDRSZ; i++)
119 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
120 best.base = -1;
121 best.len = 0;
122 cur.base = -1;
123 cur.len = 0;
124 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
125 if (words[i] == 0) {
126 if (cur.base == -1)
127 cur.base = i, cur.len = 1;
128 else
129 cur.len++;
130 } else {
131 if (cur.base != -1) {
132 if (best.base == -1 || cur.len > best.len)
133 best = cur;
134 cur.base = -1;
135 }
136 }
137 }
138 if (cur.base != -1) {
139 if (best.base == -1 || cur.len > best.len)
140 best = cur;
141 }
142 if (best.base != -1 && best.len < 2)
143 best.base = -1;
144
145 /*
146 * Format the result.
147 */
148 tp = tmp;
149 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
150 /* Are we inside the best run of 0x00's? */
151 if (best.base != -1 && i >= best.base &&
152 i < (best.base + best.len)) {
153 if (i == best.base)
154 *tp++ = ':';
155 continue;
156 }
157 /* Are we following an initial run of 0x00s or any real hex? */
158 if (i != 0)
159 *tp++ = ':';
160 /* Is this address an encapsulated IPv4? */
161 if (i == 6 && best.base == 0 && (best.len == 6 ||
162 (best.len == 7 && words[7] != 0x0001) ||
163 (best.len == 5 && words[5] == 0xffff))) {
164 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
165 return (NULL);
166 tp += strlen(tp);
167 break;
168 }
169 tp += sprintf(tp, "%x", words[i]);
170 }
171 /* Was it a trailing run of 0x00's? */
172 if (best.base != -1 && (best.base + best.len) ==
173 (NS_IN6ADDRSZ / NS_INT16SZ))
174 *tp++ = ':';
175 *tp++ = '\0';
176
177 /*
178 * Check for overflow, copy, and we're done.
179 */
180 if ((socklen_t)(tp - tmp) > size) {
181 return (NULL);
182 }
183 strcpy(dst, tmp);
184 return (dst);
185 }
186
187 /*! \file */
188
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