summaryrefslogtreecommitdiff
path: root/missing/inet_ntop.c
blob: db741a8fb20a959df5e373646b6568d1084e7e08 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
/*
 * Copyright (c) 1999 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the Kungliga Tekniska
 *      Högskolan and its contributors.
 *
 * 4. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <errno.h>

/*
 *
 */

#ifndef IN6ADDRSZ
#define IN6ADDRSZ   16   /* IPv6 T_AAAA */
#endif

#ifndef INT16SZ
#define INT16SZ     2    /* word size */
#endif

static const char *
inet_ntop_v4 (const void *src, char *dst, size_t size)
{
    const char digits[] = "0123456789";
    int i;
    struct in_addr *addr = (struct in_addr *)src;
    u_long a = ntohl(addr->s_addr);
    const char *orig_dst = dst;

    if (size < INET_ADDRSTRLEN) {
	errno = ENOSPC;
	return NULL;
    }
    for (i = 0; i < 4; ++i) {
	int n = (a >> (24 - i * 8)) & 0xFF;
	int non_zerop = 0;

	if (non_zerop || n / 100 > 0) {
	    *dst++ = digits[n / 100];
	    n %= 100;
	    non_zerop = 1;
	}
	if (non_zerop || n / 10 > 0) {
	    *dst++ = digits[n / 10];
	    n %= 10;
	    non_zerop = 1;
	}
	*dst++ = digits[n];
	if (i != 3)
	    *dst++ = '.';
    }
    *dst++ = '\0';
    return orig_dst;
}

#ifdef INET6
/*
 * Convert IPv6 binary address into presentation (printable) format.
 */
static const char *
inet_ntop_v6 (const u_char *src, char *dst, size_t size)
{
  /*
   * Note that int32_t and int16_t need only be "at least" large enough
   * to contain a value of the specified size.  On some systems, like
   * Crays, there is no such thing as an integer variable with 16 bits.
   * Keep this in mind if you think this function should have been coded
   * to use pointer overlays.  All the world's not a VAX.
   */
  char  tmp [INET6_ADDRSTRLEN+1];
  char *tp;
  struct {
    long base;
    long len;
  } best, cur;
  u_long words [IN6ADDRSZ / INT16SZ];
  int    i;

  /* Preprocess:
   *  Copy the input (bytewise) array into a wordwise array.
   *  Find the longest run of 0x00's in src[] for :: shorthanding.
   */
  memset (words, 0, sizeof(words));
  for (i = 0; i < IN6ADDRSZ; i++)
      words[i/2] |= (src[i] << ((1 - (i % 2)) << 3));

  best.base = -1;
  cur.base  = -1;
  for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
  {
    if (words[i] == 0)
    {
      if (cur.base == -1)
           cur.base = i, cur.len = 1;
      else cur.len++;
    }
    else if (cur.base != -1)
    {
      if (best.base == -1 || cur.len > best.len)
         best = cur;
      cur.base = -1;
    }
  }
  if ((cur.base != -1) && (best.base == -1 || cur.len > best.len))
     best = cur;
  if (best.base != -1 && best.len < 2)
     best.base = -1;

  /* Format the result.
   */
  tp = tmp;
  for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
  {
    /* Are we inside the best run of 0x00's?
     */
    if (best.base != -1 && i >= best.base && i < (best.base + best.len))
    {
      if (i == best.base)
         *tp++ = ':';
      continue;
    }

    /* Are we following an initial run of 0x00s or any real hex?
     */
    if (i != 0)
       *tp++ = ':';

    /* Is this address an encapsulated IPv4?
     */
    if (i == 6 && best.base == 0 &&
        (best.len == 6 || (best.len == 5 && words[5] == 0xffff)))
    {
      if (!inet_ntop_v4(src+12, tp, sizeof(tmp) - (tp - tmp)))
      {
        errno = ENOSPC;
        return (NULL);
      }
      tp += strlen(tp);
      break;
    }
    tp += sprintf (tp, "%lX", words[i]);
  }

  /* Was it a trailing run of 0x00's?
   */
  if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
     *tp++ = ':';
  *tp++ = '\0';

  /* Check for overflow, copy, and we're done.
   */
  if ((size_t)(tp - tmp) > size)
  {
    errno = ENOSPC;
    return (NULL);
  }
  return strcpy (dst, tmp);
  return (NULL);
}
#endif   /* INET6 */


const char *
inet_ntop(int af, const void *src, char *dst, size_t size)
{
    switch (af) {
    case AF_INET :
	return inet_ntop_v4 (src, dst, size);
#ifdef INET6
    case AF_INET6:
         return inet_ntop_v6 ((const u_char*)src, dst, size);
#endif
    default :
	errno = EAFNOSUPPORT;
	return NULL;
    }
}