1 /*
2 * Copyright (c) 1999 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the Kungliga Tekniska
20 * H�gskolan and its contributors.
21 *
22 * 4. Neither the name of the Institute nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39 #ifdef HAVE_CONFIG_H
40 #include "config.h"
41 #endif
42
43 #include <tcpdump-stdinc.h>
44
45 #include <stdio.h>
46
47 /*
48 *
49 */
50
51 #ifndef IN6ADDRSZ
52 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */
53 #endif
54
55 #ifndef INT16SZ
56 #define INT16SZ 2 /* word size */
57 #endif
58
59 static const char *
inet_ntop_v4(const void * src,char * dst,size_t size)60 inet_ntop_v4 (const void *src, char *dst, size_t size)
61 {
62 const char digits[] = "0123456789";
63 int i;
64 struct in_addr *addr = (struct in_addr *)src;
65 u_long a = ntohl(addr->s_addr);
66 const char *orig_dst = dst;
67
68 if (size < INET_ADDRSTRLEN) {
69 errno = ENOSPC;
70 return NULL;
71 }
72 for (i = 0; i < 4; ++i) {
73 int n = (a >> (24 - i * 8)) & 0xFF;
74 int non_zerop = 0;
75
76 if (non_zerop || n / 100 > 0) {
77 *dst++ = digits[n / 100];
78 n %= 100;
79 non_zerop = 1;
80 }
81 if (non_zerop || n / 10 > 0) {
82 *dst++ = digits[n / 10];
83 n %= 10;
84 non_zerop = 1;
85 }
86 *dst++ = digits[n];
87 if (i != 3)
88 *dst++ = '.';
89 }
90 *dst++ = '\0';
91 return orig_dst;
92 }
93
94 #ifdef INET6
95 /*
96 * Convert IPv6 binary address into presentation (printable) format.
97 */
98 static const char *
inet_ntop_v6(const u_char * src,char * dst,size_t size)99 inet_ntop_v6 (const u_char *src, char *dst, size_t size)
100 {
101 /*
102 * Note that int32_t and int16_t need only be "at least" large enough
103 * to contain a value of the specified size. On some systems, like
104 * Crays, there is no such thing as an integer variable with 16 bits.
105 * Keep this in mind if you think this function should have been coded
106 * to use pointer overlays. All the world's not a VAX.
107 */
108 char tmp [INET6_ADDRSTRLEN+1];
109 char *tp;
110 struct {
111 long base;
112 long len;
113 } best, cur;
114 u_long words [IN6ADDRSZ / INT16SZ];
115 int i;
116
117 /* Preprocess:
118 * Copy the input (bytewise) array into a wordwise array.
119 * Find the longest run of 0x00's in src[] for :: shorthanding.
120 */
121 memset (words, 0, sizeof(words));
122 for (i = 0; i < IN6ADDRSZ; i++)
123 words[i/2] |= (src[i] << ((1 - (i % 2)) << 3));
124
125 best.len = 0;
126 best.base = -1;
127 cur.len = 0;
128 cur.base = -1;
129 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
130 {
131 if (words[i] == 0)
132 {
133 if (cur.base == -1)
134 cur.base = i, cur.len = 1;
135 else cur.len++;
136 }
137 else if (cur.base != -1)
138 {
139 if (best.base == -1 || cur.len > best.len)
140 best = cur;
141 cur.base = -1;
142 }
143 }
144 if ((cur.base != -1) && (best.base == -1 || cur.len > best.len))
145 best = cur;
146 if (best.base != -1 && best.len < 2)
147 best.base = -1;
148
149 /* Format the result.
150 */
151 tp = tmp;
152 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
153 {
154 /* Are we inside the best run of 0x00's?
155 */
156 if (best.base != -1 && i >= best.base && i < (best.base + best.len))
157 {
158 if (i == best.base)
159 *tp++ = ':';
160 continue;
161 }
162
163 /* Are we following an initial run of 0x00s or any real hex?
164 */
165 if (i != 0)
166 *tp++ = ':';
167
168 /* Is this address an encapsulated IPv4?
169 */
170 if (i == 6 && best.base == 0 &&
171 (best.len == 6 || (best.len == 5 && words[5] == 0xffff)))
172 {
173 if (!inet_ntop_v4(src+12, tp, sizeof(tmp) - (tp - tmp)))
174 {
175 errno = ENOSPC;
176 return (NULL);
177 }
178 tp += strlen(tp);
179 break;
180 }
181 tp += sprintf (tp, "%lx", words[i]);
182 }
183
184 /* Was it a trailing run of 0x00's?
185 */
186 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
187 *tp++ = ':';
188 *tp++ = '\0';
189
190 /* Check for overflow, copy, and we're done.
191 */
192 if ((size_t)(tp - tmp) > size)
193 {
194 errno = ENOSPC;
195 return (NULL);
196 }
197 return strcpy (dst, tmp);
198 }
199 #endif /* INET6 */
200
201
202 const char *
inet_ntop(int af,const void * src,char * dst,size_t size)203 inet_ntop(int af, const void *src, char *dst, size_t size)
204 {
205 switch (af) {
206 case AF_INET :
207 return inet_ntop_v4 (src, dst, size);
208 #ifdef INET6
209 case AF_INET6:
210 return inet_ntop_v6 ((const u_char*)src, dst, size);
211 #endif
212 default :
213 errno = EAFNOSUPPORT;
214 return NULL;
215 }
216 }
217