StdLib/BsdSocketLib/inet_net_ntop.c

   1 /*
   2  * Copyright (c) 1996 by 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 DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  */
  17
  18 #if defined(LIBC_SCCS) && !defined(lint)
  19 static const char orig_rcsid[] = "From Id: inet_net_ntop.c,v 8.2 1996/08/08 06:54:44 vixie Exp";
  20 static const char rcsid[] = "$Id: inet_net_ntop.c,v 1.1.1.1 2003/11/19 01:51:29 kyu3 Exp $";
  21 #endif
  22
  23 #include <sys/types.h>
  24 #include <sys/socket.h>
  25 #include <netinet/in.h>
  26 #include <arpa/inet.h>
  27
  28 #include <errno.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <stdlib.h>
  32
  33 #ifdef SPRINTF_CHAR
  34 # define SPRINTF(x) strlen(sprintf/**/x)
  35 #else
  36 # define SPRINTF(x) ((size_t)sprintf x)
  37 #endif
  38
  39 static char *   inet_net_ntop_ipv4 (const u_char *src, int bits,
  40                                         char *dst, size_t size);
  41
  42 /*
  43  * char *
  44  * inet_net_ntop(af, src, bits, dst, size)
  45  *      convert network number from network to presentation format.
  46  *      generates CIDR style result always.
  47  * return:
  48  *      pointer to dst, or NULL if an error occurred (check errno).
  49  * author:
  50  *      Paul Vixie (ISC), July 1996
  51  */
  52 char *
  53 inet_net_ntop(
  54         int af,
  55         const void *src,
  56         int bits,
  57         char *dst,
  58         size_t size
  59         )
  60 {
  61         switch (af) {
  62         case AF_INET:
  63                 return (inet_net_ntop_ipv4(src, bits, dst, size));
  64         default:
  65                 errno = EAFNOSUPPORT;
  66                 return (NULL);
  67         }
  68 }
  69
  70 /*
  71  * static char *
  72  * inet_net_ntop_ipv4(src, bits, dst, size)
  73  *      convert IPv4 network number from network to presentation format.
  74  *      generates CIDR style result always.
  75  * return:
  76  *      pointer to dst, or NULL if an error occurred (check errno).
  77  * note:
  78  *      network byte order assumed.  this means 192.5.5.240/28 has
  79  *      0x11110000 in its fourth octet.
  80  * author:
  81  *      Paul Vixie (ISC), July 1996
  82  */
  83 static char *
  84 inet_net_ntop_ipv4(
  85         const u_char *src,
  86         int bits,
  87         char *dst,
  88         size_t size
  89         )
  90 {
  91         char *odst = dst;
  92         char *t;
  93         u_int m;
  94         int b;
  95
  96         if (bits < 0 || bits > 32) {
  97                 errno = EINVAL;
  98                 return (NULL);
  99         }
 100         if (bits == 0) {
 101                 if (size < sizeof "0")
 102                         goto emsgsize;
 103                 *dst++ = '0';
 104                 *dst = '\0';
 105         }
 106
 107         /* Format whole octets. */
 108         for (b = bits / 8; b > 0; b--) {
 109                 if (size < sizeof "255.")
 110                         goto emsgsize;
 111                 t = dst;
 112                 dst += SPRINTF((dst, "%u", *src++));
 113                 if (b > 1) {
 114                         *dst++ = '.';
 115                         *dst = '\0';
 116                 }
 117                 size -= (size_t)(dst - t);
 118         }
 119
 120         /* Format partial octet. */
 121         b = bits % 8;
 122         if (b > 0) {
 123                 if (size < sizeof ".255")
 124                         goto emsgsize;
 125                 t = dst;
 126                 if (dst != odst)
 127                         *dst++ = '.';
 128                 m = ((1 << b) - 1) << (8 - b);
 129                 dst += SPRINTF((dst, "%u", *src & m));
 130                 size -= (size_t)(dst - t);
 131         }
 132
 133         /* Format CIDR /width. */
 134         if (size < sizeof "/32")
 135                 goto emsgsize;
 136         dst += SPRINTF((dst, "/%u", bits));
 137         return (odst);
 138
 139  emsgsize:
 140         errno = EMSGSIZE;
 141         return (NULL);
 142 }