compat/inet_ntop.cc

   1 /*
   2  * Copyright (C) 1996-2019 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /*
  10  *  Shamelessly duplicated from the bind9 public sources
  11  *  for use by the Squid Project under ISC written permission
  12  *  included "as found" below.
  13  *
  14  * Update/Maintenance History:
  15  *
  16  *    24-Sep-2007 : Copied from bind 9.3.3
  17  *          - Added protection around libray headers
  18  *          - Altered configure checks
  19  *          - Un-hacked slightly to use system gethostbyname()
  20  *
  21  *    06-Oct-2007 : Various fixes to allow the build on MinGW
  22  *
  23  *    28-Oct-2007: drop some dead code. now tested working without.
  24  *
  25  *    04-Nov-2010: drop SPRINTF casting macro
  26  *
  27  *    13-Jan-2015 : Various fixed for C++ and MinGW native build
  28  *
  29  *  Original License and code follows.
  30  */
  31
  32 #include "squid.h"
  33
  34 #if !HAVE_DECL_INET_NTOP
  35
  36 /*
  37  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
  38  * Copyright (c) 1996-1999 by Internet Software Consortium.
  39  *
  40  * Permission to use, copy, modify, and distribute this software for any
  41  * purpose with or without fee is hereby granted, provided that the above
  42  * copyright notice and this permission notice appear in all copies.
  43  *
  44  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  45  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  46  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  47  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  48  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  49  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  50  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  51  */
  52
  53 #if defined(LIBC_SCCS) && !defined(lint)
  54 static const char rcsid[] = "inet_ntop.c,v 1.1.2.1.8.2 2005/11/03 23:08:40 marka Exp";
  55 #endif /* LIBC_SCCS and not lint */
  56
  57 #if HAVE_SYS_PARAM_H
  58 #include <sys/param.h>
  59 #endif
  60 #if HAVE_SYS_TYPES_H
  61 #include <sys/types.h>
  62 #endif
  63 #if HAVE_SYS_SOCKET_H
  64 #include <sys/socket.h>
  65 #endif
  66
  67 #if HAVE_NETINET_IN_H
  68 #include <netinet/in.h>
  69 #endif
  70 #if HAVE_ARPA_INET_H
  71 #include <arpa/inet.h>
  72 #endif
  73 #if HAVE_ARPA_NAMESER_H
  74 #include <arpa/nameser.h>
  75 #endif
  76
  77 #if HAVE_ERRNO_H
  78 #include <errno.h>
  79 #endif
  80 #if HAVE_STRING_H
  81 #include <string.h>
  82 #endif
  83
  84 #if ! defined(NS_INADDRSZ)
  85 #define NS_INADDRSZ      4
  86 #endif
  87 #if ! defined(NS_IN6ADDRSZ)
  88 #define NS_IN6ADDRSZ    16
  89 #endif
  90 #if ! defined(NS_INT16SZ)
  91 #define NS_INT16SZ      2
  92 #endif
  93
  94 /*
  95  * WARNING: Don't even consider trying to compile this on a system where
  96  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  97  */
  98
  99 static const char *inet_ntop4 (const u_char *src, char *dst, size_t size);
 100 static const char *inet_ntop6 (const u_char *src, char *dst, size_t size);
 101
 102 /* char *
 103  * inet_ntop(af, src, dst, size)
 104  *  convert a network format address to presentation format.
 105  * return:
 106  *  pointer to presentation format address (`dst'), or NULL (see errno).
 107  * author:
 108  *  Paul Vixie, 1996.
 109  */
 110 const char *
 111 xinet_ntop(int af, const void *src, char *dst, size_t size)
 112 {
 113     switch (af) {
 114     case AF_INET:
 115         return (inet_ntop4((const u_char*)src, dst, size));
 116     case AF_INET6:
 117         return (inet_ntop6((const u_char*)src, dst, size));
 118     default:
 119         errno = EAFNOSUPPORT;
 120         return (NULL);
 121     }
 122     /* NOTREACHED */
 123 }
 124
 125 /* const char *
 126  * inet_ntop4(src, dst, size)
 127  *  format an IPv4 address
 128  * return:
 129  *  `dst' (as a const)
 130  * notes:
 131  *  (1) uses no statics
 132  *  (2) takes a u_char* not an in_addr as input
 133  * author:
 134  *  Paul Vixie, 1996.
 135  */
 136 static const char *
 137 inet_ntop4(const u_char *src, char *dst, size_t size)
 138 {
 139     static const char fmt[] = "%u.%u.%u.%u";
 140     char tmp[sizeof("255.255.255.255")+1];
 141
 142     if ((size_t)snprintf(tmp, min(sizeof(tmp),size), fmt, src[0], src[1], src[2], src[3]) >= size) {
 143         errno = ENOSPC;
 144         return (NULL);
 145     }
 146     strcpy(dst, tmp);
 147     return (dst);
 148 }
 149
 150 /* const char *
 151  * inet_ntop6(src, dst, size)
 152  *  convert IPv6 binary address into presentation (printable) format
 153  * author:
 154  *  Paul Vixie, 1996.
 155  */
 156 static const char *
 157 inet_ntop6(const u_char *src, char *dst, size_t size)
 158 {
 159     /*
 160      * Note that int32_t and int16_t need only be "at least" large enough
 161      * to contain a value of the specified size.  On some systems, like
 162      * Crays, there is no such thing as an integer variable with 16 bits.
 163      * Keep this in mind if you think this function should have been coded
 164      * to use pointer overlays.  All the world's not a VAX.
 165      */
 166     char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
 167     struct { int base, len; } best, cur;
 168     u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
 169     int i;
 170
 171     /*
 172      * Preprocess:
 173      *  Copy the input (bytewise) array into a wordwise array.
 174      *  Find the longest run of 0x00's in src[] for :: shorthanding.
 175      */
 176     memset(words, '\0', sizeof words);
 177     for (i = 0; i < NS_IN6ADDRSZ; i++)
 178         words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 179     best.base = -1;
 180     best.len = 0;
 181     cur.base = -1;
 182     cur.len = 0;
 183     for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 184         if (words[i] == 0) {
 185             if (cur.base == -1)
 186                 cur.base = i, cur.len = 1;
 187             else
 188                 cur.len++;
 189         } else {
 190             if (cur.base != -1) {
 191                 if (best.base == -1 || cur.len > best.len)
 192                     best = cur;
 193                 cur.base = -1;
 194             }
 195         }
 196     }
 197     if (cur.base != -1) {
 198         if (best.base == -1 || cur.len > best.len)
 199             best = cur;
 200     }
 201     if (best.base != -1 && best.len < 2)
 202         best.base = -1;
 203
 204     /*
 205      * Format the result.
 206      */
 207     tp = tmp;
 208     for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 209         /* Are we inside the best run of 0x00's? */
 210         if (best.base != -1 && i >= best.base &&
 211                 i < (best.base + best.len)) {
 212             if (i == best.base)
 213                 *tp++ = ':';
 214             continue;
 215         }
 216         /* Are we following an initial run of 0x00s or any real hex? */
 217         if (i != 0)
 218             *tp++ = ':';
 219         /* Is this address an encapsulated IPv4? */
 220         if (i == 6 && best.base == 0 && (best.len == 6 ||
 221                                          (best.len == 7 && words[7] != 0x0001) ||
 222                                          (best.len == 5 && words[5] == 0xffff))) {
 223             if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 224                 return (NULL);
 225             tp += strlen(tp);
 226             break;
 227         }
 228         tp += snprintf(tp, (tmp + sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255") - tp), "%x", words[i]);
 229     }
 230     /* Was it a trailing run of 0x00's? */
 231     if (best.base != -1 && (best.base + best.len) ==
 232             (NS_IN6ADDRSZ / NS_INT16SZ))
 233         *tp++ = ':';
 234     *tp++ = '\0';
 235
 236     /*
 237      * Check for overflow, copy, and we're done.
 238      */
 239     if ((size_t)(tp - tmp) > size) {
 240         errno = ENOSPC;
 241         return (NULL);
 242     }
 243     strcpy(dst, tmp);
 244     return (dst);
 245 }
 246
 247 #endif /* HAVE_DECL_INET_NTOP */
 248