src/add-ons/kernel/network/protocols/ipv6/ipv6_utils.cpp

   1 /*
   2  * Copyright 2010, Haiku, Inc. All Rights Reserved.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6 /*
   7  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   8  * Copyright (c) 1996-1999 by Internet Software Consortium.
   9  *
  10  * Permission to use, copy, modify, and distribute this software for any
  11  * purpose with or without fee is hereby granted, provided that the above
  12  * copyright notice and this permission notice appear in all copies.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  15  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  16  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  17  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  18  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  19  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  20  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  21  */
  22
  23
  24 #include <net_datalink.h>
  25
  26 #include <ByteOrder.h>
  27 #include <KernelExport.h>
  28 #include <NetUtilities.h>
  29
  30 #include <memory.h>
  31 #include <netinet6/in6.h>
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35
  36 #include "ipv6_utils.h"
  37
  38
  39 #define NS_IN6ADDRSZ 16
  40 #define NS_INT16SZ 2
  41
  42 #define SPRINTF(x) ((size_t)sprintf x)
  43
  44
  45 /*!     Convert IPv6 binary address into presentation (printable) format.
  46         Author: Paul Vixie, 1996.
  47         \return pointer to dst string if address as been printed
  48         \return NULL if the buffer is too short
  49 */
  50 const char *
  51 ip6_sprintf(const in6_addr *srcaddr, char *dst, size_t size)
  52 {
  53         /*
  54          * Note that int32_t and int16_t need only be "at least" large enough
  55          * to contain a value of the specified size.  On some systems, like
  56          * Crays, there is no such thing as an integer variable with 16 bits.
  57          * Keep this in mind if you think this function should have been coded
  58          * to use pointer overlays.      All the world's not a VAX.
  59          */
  60         char tmp[INET6_ADDRSTRLEN], *tp;
  61         struct { int base, len; } best, cur;
  62         uint16 words[NS_IN6ADDRSZ / NS_INT16SZ];
  63         int i;
  64         const uint8 *src = srcaddr->s6_addr;
  65
  66         /*
  67          * Preprocess:
  68          *      Copy the input (bytewise) array into a wordwise array.
  69          *      Find the longest run of 0x00's in src[] for :: shorthanding.
  70          */
  71         memset(words, '\0', sizeof words);
  72         for (i = 0; i < NS_IN6ADDRSZ; i++)
  73                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
  74         best.base = -1;
  75         best.len = 0;
  76         cur.base = -1;
  77         cur.len = 0;
  78         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
  79                 if (words[i] == 0) {
  80                         if (cur.base == -1)
  81                                 cur.base = i, cur.len = 1;
  82                         else
  83                                 cur.len++;
  84                 } else {
  85                         if (cur.base != -1) {
  86                                 if (best.base == -1 || cur.len > best.len)
  87                                         best = cur;
  88                                 cur.base = -1;
  89                         }
  90                 }
  91         }
  92         if (cur.base != -1) {
  93                 if (best.base == -1 || cur.len > best.len)
  94                         best = cur;
  95         }
  96         if (best.base != -1 && best.len < 2)
  97                 best.base = -1;
  98
  99         /*
 100          * Format the result.
 101          */
 102         tp = tmp;
 103         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 104                 /* Are we inside the best run of 0x00's? */
 105                 if (best.base != -1 && i >= best.base &&
 106                         i < (best.base + best.len)) {
 107                         if (i == best.base)
 108                                 *tp++ = ':';
 109                         continue;
 110                 }
 111                 /* Are we following an initial run of 0x00s or any real hex? */
 112                 if (i != 0)
 113                         *tp++ = ':';
 114                 /* Is this address an encapsulated IPv4? */
 115 #if 0
 116                 if (i == 6 && best.base == 0 && (best.len == 6 ||
 117                         (best.len == 7 && words[7] != 0x0001) ||
 118                         (best.len == 5 && words[5] == 0xffff))) {
 119                         if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 120                                 return (NULL);
 121                         tp += strlen(tp);
 122                         break;
 123                 }
 124 #endif
 125                 tp += SPRINTF((tp, "%x", words[i]));
 126         }
 127         /* Was it a trailing run of 0x00's? */
 128         if (best.base != -1 && (best.base + best.len) ==
 129                 (NS_IN6ADDRSZ / NS_INT16SZ))
 130                 *tp++ = ':';
 131         *tp++ = '\0';
 132
 133         /*
 134          * Check for overflow, copy, and we're done.
 135          */
 136         if ((size_t)(tp - tmp) > size)
 137                 return NULL;
 138
 139         strcpy(dst, tmp);
 140         return dst;
 141 }