1/*
2 * Copyright (C) 1996-2001  Internet Software Consortium.
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
9 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
10 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
11 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
13 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
14 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
15 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17/*
18 * Original code by Paul Vixie. "curlified" by Gisle Vanem.
19 */
20
21#include "setup.h"
22
23#ifndef HAVE_INET_NTOP
24
25#ifdef HAVE_SYS_PARAM_H
26#include <sys/param.h>
27#endif
28#ifdef HAVE_SYS_SOCKET_H
29#include <sys/socket.h>
30#endif
31#ifdef HAVE_NETINET_IN_H
32#include <netinet/in.h>
33#endif
34#ifdef HAVE_ARPA_INET_H
35#include <arpa/inet.h>
36#endif
37
38#define _MPRINTF_REPLACE /* use our functions only */
39#include <curl/mprintf.h>
40
41#include "inet_ntop.h"
42
43#define IN6ADDRSZ       16
44#define INADDRSZ         4
45#define INT16SZ          2
46
47/*
48 * Format an IPv4 address, more or less like inet_ntoa().
49 *
50 * Returns `dst' (as a const)
51 * Note:
52 *  - uses no statics
53 *  - takes a unsigned char* not an in_addr as input
54 */
55static char *inet_ntop4 (const unsigned char *src, char *dst, size_t size)
56{
57  char tmp[sizeof "255.255.255.255"];
58  size_t len;
59
60  DEBUGASSERT(size >= 16);
61
62  tmp[0] = '\0';
63  (void)snprintf(tmp, sizeof(tmp), "%d.%d.%d.%d",
64          ((int)((unsigned char)src[0])) & 0xff,
65          ((int)((unsigned char)src[1])) & 0xff,
66          ((int)((unsigned char)src[2])) & 0xff,
67          ((int)((unsigned char)src[3])) & 0xff);
68
69  len = strlen(tmp);
70  if(len == 0 || len >= size) {
71    SET_ERRNO(ENOSPC);
72    return (NULL);
73  }
74  strcpy(dst, tmp);
75  return dst;
76}
77
78#ifdef ENABLE_IPV6
79/*
80 * Convert IPv6 binary address into presentation (printable) format.
81 */
82static char *inet_ntop6 (const unsigned char *src, char *dst, size_t size)
83{
84  /*
85   * Note that int32_t and int16_t need only be "at least" large enough
86   * to contain a value of the specified size.  On some systems, like
87   * Crays, there is no such thing as an integer variable with 16 bits.
88   * Keep this in mind if you think this function should have been coded
89   * to use pointer overlays.  All the world's not a VAX.
90   */
91  char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
92  char *tp;
93  struct {
94    long base;
95    long len;
96  } best, cur;
97  unsigned long words[IN6ADDRSZ / INT16SZ];
98  int i;
99
100  /* Preprocess:
101   *  Copy the input (bytewise) array into a wordwise array.
102   *  Find the longest run of 0x00's in src[] for :: shorthanding.
103   */
104  memset(words, '\0', sizeof(words));
105  for(i = 0; i < IN6ADDRSZ; i++)
106    words[i/2] |= (src[i] << ((1 - (i % 2)) << 3));
107
108  best.base = -1;
109  cur.base  = -1;
110  best.len = 0;
111  cur.len = 0;
112
113  for(i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
114    if(words[i] == 0) {
115      if(cur.base == -1)
116        cur.base = i, cur.len = 1;
117      else
118        cur.len++;
119    }
120    else if(cur.base != -1) {
121      if(best.base == -1 || cur.len > best.len)
122        best = cur;
123      cur.base = -1;
124    }
125  }
126  if((cur.base != -1) && (best.base == -1 || cur.len > best.len))
127    best = cur;
128  if(best.base != -1 && best.len < 2)
129    best.base = -1;
130  /* Format the result. */
131  tp = tmp;
132  for(i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
133    /* Are we inside the best run of 0x00's? */
134    if(best.base != -1 && i >= best.base && i < (best.base + best.len)) {
135      if(i == best.base)
136        *tp++ = ':';
137      continue;
138    }
139
140    /* Are we following an initial run of 0x00s or any real hex?
141     */
142    if(i != 0)
143      *tp++ = ':';
144
145    /* Is this address an encapsulated IPv4?
146     */
147    if(i == 6 && best.base == 0 &&
148        (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
149      if(!inet_ntop4(src+12, tp, sizeof(tmp) - (tp - tmp))) {
150        SET_ERRNO(ENOSPC);
151        return (NULL);
152      }
153      tp += strlen(tp);
154      break;
155    }
156    tp += snprintf(tp, 5, "%lx", words[i]);
157  }
158
159  /* Was it a trailing run of 0x00's?
160   */
161  if(best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
162     *tp++ = ':';
163  *tp++ = '\0';
164
165  /* Check for overflow, copy, and we're done.
166   */
167  if((size_t)(tp - tmp) > size) {
168    SET_ERRNO(ENOSPC);
169    return (NULL);
170  }
171  strcpy(dst, tmp);
172  return dst;
173}
174#endif  /* ENABLE_IPV6 */
175
176/*
177 * Convert a network format address to presentation format.
178 *
179 * Returns pointer to presentation format address (`buf').
180 * Returns NULL on error and errno set with the specific
181 * error, EAFNOSUPPORT or ENOSPC.
182 *
183 * On Windows we store the error in the thread errno, not
184 * in the winsock error code. This is to avoid losing the
185 * actual last winsock error. So use macro ERRNO to fetch the
186 * errno this function sets when returning NULL, not SOCKERRNO.
187 */
188char *Curl_inet_ntop(int af, const void *src, char *buf, size_t size)
189{
190  switch (af) {
191  case AF_INET:
192    return inet_ntop4((const unsigned char*)src, buf, size);
193#ifdef ENABLE_IPV6
194  case AF_INET6:
195    return inet_ntop6((const unsigned char*)src, buf, size);
196#endif
197  default:
198    SET_ERRNO(EAFNOSUPPORT);
199    return NULL;
200  }
201}
202#endif  /* HAVE_INET_NTOP */
203