1 /* $OpenBSD: inet_ntop.c,v 1.9 2014/02/05 14:20:43 millert Exp $ */
2
3 /*
4 * SPDX-License-Identifier: ISC
5 *
6 * Copyright (c) 1996 by Internet Software Consortium.
7 *
8 * Permission to use, copy, modify, and distribute this software for any
9 * purpose with or without fee is hereby granted, provided that the above
10 * copyright notice and this permission notice appear in all copies.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
13 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
14 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
15 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
16 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
17 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
18 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
19 * SOFTWARE.
20 */
21
22 #include <config.h>
23
24 #if !defined(HAVE_INET_NTOP)
25
26 #include <sys/types.h>
27 #include <sys/socket.h>
28 #include <netinet/in.h>
29 #include <arpa/inet.h>
30 #include <arpa/nameser.h>
31 #include <string.h>
32 #include <errno.h>
33 #include <stdio.h>
34
35 #include "sudo_compat.h"
36
37 #ifndef EAFNOSUPPORT
38 # define EAFNOSUPPORT EINVAL
39 #endif
40
41 #ifndef NS_IN6ADDRSZ
42 # ifdef IN6ADDRSZ
43 # define NS_IN6ADDRSZ IN6ADDRSZ
44 # else
45 # define NS_IN6ADDRSZ 16
46 # endif
47 #endif
48 #ifndef NS_INT16SZ
49 # ifdef INT16SZ
50 # define NS_INT16SZ INT16SZ
51 # else
52 # define NS_INT16SZ 2
53 # endif
54 #endif
55 #ifndef INET6_ADDRSTRLEN
56 # define INET6_ADDRSTRLEN 46
57 #endif
58
59 /*
60 * WARNING: Don't even consider trying to compile this on a system where
61 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
62 */
63
64 /* const char *
65 * inet_ntop4(src, dst, size)
66 * format an IPv4 address, more or less like inet_ntoa()
67 * return:
68 * `dst' (as a const)
69 * notes:
70 * (1) uses no statics
71 * (2) takes a unsigned char* not an in_addr as input
72 * author:
73 * Paul Vixie, 1996.
74 */
75 static const char *
inet_ntop4(const unsigned char * src,char * dst,socklen_t size)76 inet_ntop4(const unsigned char *src, char *dst, socklen_t size)
77 {
78 const char fmt[] = "%u.%u.%u.%u";
79 int len;
80
81 len = snprintf(dst, size, fmt, src[0], src[1], src[2], src[3]);
82 if (len < 0 || len >= size) {
83 errno = ENOSPC;
84 return (NULL);
85 }
86 return (dst);
87 }
88
89 #ifdef HAVE_STRUCT_IN6_ADDR
90 /* const char *
91 * inet_ntop6(src, dst, size)
92 * convert IPv6 binary address into presentation (printable) format
93 * author:
94 * Paul Vixie, 1996.
95 */
96 static const char *
inet_ntop6(const unsigned char * src,char * dst,socklen_t size)97 inet_ntop6(const unsigned char *src, char *dst, socklen_t size)
98 {
99 /*
100 * Note that int32_t and int16_t need only be "at least" large enough
101 * to contain a value of the specified size. On some systems, like
102 * Crays, there is no such thing as an integer variable with 16 bits.
103 * Keep this in mind if you think this function should have been coded
104 * to use pointer overlays. All the world's not a VAX.
105 */
106 char *cp, *ep;
107 struct { int base, len; } best, cur;
108 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
109 int i;
110 int advance;
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 cp = dst;
149 ep = dst + size;
150 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ) && cp < ep; 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 if (cp + 1 >= ep) {
156 errno = ENOSPC;
157 return (NULL);
158 }
159 *cp++ = ':';
160 }
161 continue;
162 }
163 /* Are we following an initial run of 0x00s or any real hex? */
164 if (i != 0) {
165 if (cp + 1 >= ep) {
166 errno = ENOSPC;
167 return (NULL);
168 }
169 *cp++ = ':';
170 }
171 /* Is this address an encapsulated IPv4? */
172 if (i == 6 && best.base == 0 &&
173 (best.len == 6 ||
174 (best.len == 7 && words[7] != 0x0001) ||
175 (best.len == 5 && words[5] == 0xffff))) {
176 if (!inet_ntop4(src + 12, cp, (socklen_t)(ep - cp)))
177 return (NULL);
178 cp += strlen(cp);
179 break;
180 }
181 advance = snprintf(cp, (size_t)(ep - cp), "%x", words[i]);
182 if (advance <= 0 || advance >= ep - cp) {
183 errno = ENOSPC;
184 return (NULL);
185 }
186 cp += advance;
187 }
188 /* Was it a trailing run of 0x00's? */
189 if (best.base != -1 &&
190 (best.base + best.len) == (NS_IN6ADDRSZ / NS_INT16SZ)) {
191 if (cp + 1 >= ep) {
192 errno = ENOSPC;
193 return (NULL);
194 }
195 *cp++ = ':';
196 }
197 if (cp + 1 >= ep) {
198 errno = ENOSPC;
199 return (NULL);
200 }
201 *cp++ = '\0';
202
203 return (dst);
204 }
205 #endif /* HAVE_STRUCT_IN6_ADDR */
206
207 /* const char *
208 * inet_ntop(af, src, dst, size)
209 * convert a network format address to presentation format.
210 * return:
211 * pointer to presentation format address (`dst'), or NULL (see errno).
212 * author:
213 * Paul Vixie, 1996.
214 */
215 const char *
sudo_inet_ntop(int af,const void * src,char * dst,socklen_t size)216 sudo_inet_ntop(int af, const void *src, char *dst, socklen_t size)
217 {
218 switch (af) {
219 case AF_INET:
220 return (inet_ntop4(src, dst, size));
221 #ifdef HAVE_STRUCT_IN6_ADDR
222 case AF_INET6:
223 return (inet_ntop6(src, dst, size));
224 #endif
225 default:
226 errno = EAFNOSUPPORT;
227 return (NULL);
228 }
229 /* NOTREACHED */
230 }
231
232 #endif /* !HAVE_INET_NTOP */
233