gsasl  1.10.0
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inet_ntop.c
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1 /* inet_ntop.c -- convert IPv4 and IPv6 addresses from binary to text form
2 
3  Copyright (C) 2005-2006, 2008-2021 Free Software Foundation, Inc.
4 
5  This program is free software; you can redistribute it and/or modify
6  it under the terms of the GNU General Public License as published by
7  the Free Software Foundation; either version 3, or (at your option)
8  any later version.
9 
10  This program is distributed in the hope that it will be useful,
11  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  GNU General Public License for more details.
14 
15  You should have received a copy of the GNU General Public License
16  along with this program; if not, see <https://www.gnu.org/licenses/>. */
17 
18 /*
19  * Copyright (c) 1996-1999 by Internet Software Consortium.
20  *
21  * Permission to use, copy, modify, and distribute this software for any
22  * purpose with or without fee is hereby granted, provided that the above
23  * copyright notice and this permission notice appear in all copies.
24  *
25  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
26  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
27  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
28  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
29  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
30  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
31  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
32  * SOFTWARE.
33  */
34 
35 #include <config.h>
36 
37 /* Specification. */
38 #include <arpa/inet.h>
39 
40 /* Use this to suppress gcc's "...may be used before initialized" warnings.
41  Beware: The Code argument must not contain commas. */
42 #ifndef IF_LINT
43 # if defined GCC_LINT || defined lint
44 # define IF_LINT(Code) Code
45 # else
46 # define IF_LINT(Code) /* empty */
47 # endif
48 #endif
49 
50 #if HAVE_DECL_INET_NTOP
51 
52 # undef inet_ntop
53 
54 const char *
55 rpl_inet_ntop (int af, const void *restrict src,
56  char *restrict dst, socklen_t cnt)
57 {
58  return inet_ntop (af, src, dst, cnt);
59 }
60 
61 #else
62 
63 # include <stdio.h>
64 # include <string.h>
65 # include <errno.h>
66 
67 # define NS_IN6ADDRSZ 16
68 # define NS_INT16SZ 2
69 
70 /*
71  * WARNING: Don't even consider trying to compile this on a system where
72  * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
73  */
74 typedef int verify_int_size[4 <= sizeof (int) ? 1 : -1];
75 
76 static const char *inet_ntop4 (const unsigned char *src, char *dst, socklen_t size);
77 # if HAVE_IPV6
78 static const char *inet_ntop6 (const unsigned char *src, char *dst, socklen_t size);
79 # endif
80 
81 
82 /* char *
83  * inet_ntop(af, src, dst, size)
84  * convert a network format address to presentation format.
85  * return:
86  * pointer to presentation format address ('dst'), or NULL (see errno).
87  * author:
88  * Paul Vixie, 1996.
89  */
90 const char *
91 inet_ntop (int af, const void *restrict src,
92  char *restrict dst, socklen_t cnt)
93 {
94  switch (af)
95  {
96 # if HAVE_IPV4
97  case AF_INET:
98  return (inet_ntop4 (src, dst, cnt));
99 # endif
100 
101 # if HAVE_IPV6
102  case AF_INET6:
103  return (inet_ntop6 (src, dst, cnt));
104 # endif
105 
106  default:
107  errno = EAFNOSUPPORT;
108  return (NULL);
109  }
110  /* NOTREACHED */
111 }
112 
113 /* const char *
114  * inet_ntop4(src, dst, size)
115  * format an IPv4 address
116  * return:
117  * 'dst' (as a const)
118  * notes:
119  * (1) uses no statics
120  * (2) takes a u_char* not an in_addr as input
121  * author:
122  * Paul Vixie, 1996.
123  */
124 static const char *
125 inet_ntop4 (const unsigned char *src, char *dst, socklen_t size)
126 {
127  char tmp[sizeof "255.255.255.255"];
128  int len;
129 
130  len = sprintf (tmp, "%u.%u.%u.%u", src[0], src[1], src[2], src[3]);
131  if (len < 0)
132  return NULL;
133 
134  if (len > size)
135  {
136  errno = ENOSPC;
137  return NULL;
138  }
139 
140  return strcpy (dst, tmp);
141 }
142 
143 # if HAVE_IPV6
144 
145 /* const char *
146  * inet_ntop6(src, dst, size)
147  * convert IPv6 binary address into presentation (printable) format
148  * author:
149  * Paul Vixie, 1996.
150  */
151 static const char *
152 inet_ntop6 (const unsigned char *src, char *dst, socklen_t size)
153 {
154  /*
155  * Note that int32_t and int16_t need only be "at least" large enough
156  * to contain a value of the specified size. On some systems, like
157  * Crays, there is no such thing as an integer variable with 16 bits.
158  * Keep this in mind if you think this function should have been coded
159  * to use pointer overlays. All the world's not a VAX.
160  */
161  char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
162  struct
163  {
164  int base, len;
165  } best, cur;
166  unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
167  int i;
168 
169  /*
170  * Preprocess:
171  * Copy the input (bytewise) array into a wordwise array.
172  * Find the longest run of 0x00's in src[] for :: shorthanding.
173  */
174  memset (words, '\0', sizeof words);
175  for (i = 0; i < NS_IN6ADDRSZ; i += 2)
176  words[i / 2] = (src[i] << 8) | src[i + 1];
177  best.base = -1;
178  cur.base = -1;
179  IF_LINT(best.len = 0);
180  IF_LINT(cur.len = 0);
181  for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++)
182  {
183  if (words[i] == 0)
184  {
185  if (cur.base == -1)
186  cur.base = i, cur.len = 1;
187  else
188  cur.len++;
189  }
190  else
191  {
192  if (cur.base != -1)
193  {
194  if (best.base == -1 || cur.len > best.len)
195  best = cur;
196  cur.base = -1;
197  }
198  }
199  }
200  if (cur.base != -1)
201  {
202  if (best.base == -1 || cur.len > best.len)
203  best = cur;
204  }
205  if (best.base != -1 && best.len < 2)
206  best.base = -1;
207 
208  /*
209  * Format the result.
210  */
211  tp = tmp;
212  for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++)
213  {
214  /* Are we inside the best run of 0x00's? */
215  if (best.base != -1 && i >= best.base && i < (best.base + best.len))
216  {
217  if (i == best.base)
218  *tp++ = ':';
219  continue;
220  }
221  /* Are we following an initial run of 0x00s or any real hex? */
222  if (i != 0)
223  *tp++ = ':';
224  /* Is this address an encapsulated IPv4? */
225  if (i == 6 && best.base == 0 &&
226  (best.len == 6 || (best.len == 5 && words[5] == 0xffff)))
227  {
228  if (!inet_ntop4 (src + 12, tp, sizeof tmp - (tp - tmp)))
229  return (NULL);
230  tp += strlen (tp);
231  break;
232  }
233  {
234  int len = sprintf (tp, "%x", words[i]);
235  if (len < 0)
236  return NULL;
237  tp += len;
238  }
239  }
240  /* Was it a trailing run of 0x00's? */
241  if (best.base != -1 && (best.base + best.len) ==
243  *tp++ = ':';
244  *tp++ = '\0';
245 
246  /*
247  * Check for overflow, copy, and we're done.
248  */
249  if ((socklen_t) (tp - tmp) > size)
250  {
251  errno = ENOSPC;
252  return NULL;
253  }
254 
255  return strcpy (dst, tmp);
256 }
257 
258 # endif
259 
260 #endif
#define restrict
Definition: config.h:69
#define NULL
Definition: stddef.in.h:72
static gss_OID_desc tmp
Definition: gss-extra.c:38
const char * inet_ntop(int af, const void *src, char *dst, socklen_t cnt)
Definition: inet_ntop.c:91
static const char * inet_ntop4(const unsigned char *src, char *dst, socklen_t size)
Definition: inet_ntop.c:125
#define NS_IN6ADDRSZ
Definition: inet_ntop.c:67
#define NS_INT16SZ
Definition: inet_ntop.c:68
#define IF_LINT(Code)
Definition: inet_ntop.c:46
int verify_int_size[4<=sizeof(int) ? 1 :-1]
Definition: inet_ntop.c:74