net/FreeBSD/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 #endif
  21 #include <sys/cdefs.h>
  22 __FBSDID("$FreeBSD: src/lib/libc/net/inet_net_ntop.c,v 1.7 2002/03/22 21:52:29 obrien Exp $");
  23
  24 #include <sys/types.h>
  25 #include <sys/socket.h>
  26 #include <netinet/in.h>
  27 #include <arpa/inet.h>
  28
  29 #include <errno.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <stdlib.h>
  33
  34 #ifdef SPRINTF_CHAR
  35 # define SPRINTF(x) strlen(sprintf/**/x)
  36 #else
  37 # define SPRINTF(x) ((size_t)sprintf x)
  38 #endif
  39
  40 static char *   inet_net_ntop_ipv4(const u_char *src, int bits, char *dst,
  41                     size_t size);
  42
  43 /*
  44  * char *
  45  * inet_net_ntop(af, src, bits, dst, size)
  46  *      convert network number from network to presentation format.
  47  *      generates CIDR style result always.
  48  * return:
  49  *      pointer to dst, or NULL if an error occurred (check errno).
  50  * author:
  51  *      Paul Vixie (ISC), July 1996
  52  */
  53 char *
  54 inet_net_ntop(af, src, bits, dst, size)
  55         int af;
  56         const void *src;
  57         int bits;
  58         char *dst;
  59         size_t size;
  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(src, bits, dst, size)
  85         const u_char *src;
  86         int bits;
  87         char *dst;
  88         size_t size;
  89 {
  90         char *odst = dst;
  91         char *t;
  92         u_int m;
  93         int b;
  94
  95         if (bits < 0 || bits > 32) {
  96                 errno = EINVAL;
  97                 return (NULL);
  98         }
  99         if (bits == 0) {
 100                 if (size < sizeof "0")
 101                         goto emsgsize;
 102                 *dst++ = '0';
 103                 *dst = '\0';
 104         }
 105
 106         /* Format whole octets. */
 107         for (b = bits / 8; b > 0; b--) {
 108                 if (size < sizeof "255.")
 109                         goto emsgsize;
 110                 t = dst;
 111                 dst += SPRINTF((dst, "%u", *src++));
 112                 if (b > 1) {
 113                         *dst++ = '.';
 114                         *dst = '\0';
 115                 }
 116                 size -= (size_t)(dst - t);
 117         }
 118
 119         /* Format partial octet. */
 120         b = bits % 8;
 121         if (b > 0) {
 122                 if (size < sizeof ".255")
 123                         goto emsgsize;
 124                 t = dst;
 125                 if (dst != odst)
 126                         *dst++ = '.';
 127                 m = ((1 << b) - 1) << (8 - b);
 128                 dst += SPRINTF((dst, "%u", *src & m));
 129                 size -= (size_t)(dst - t);
 130         }
 131
 132         /* Format CIDR /width. */
 133         if (size < sizeof "/32")
 134                 goto emsgsize;
 135         dst += SPRINTF((dst, "/%u", bits));
 136         return (odst);
 137
 138  emsgsize:
 139         errno = EMSGSIZE;
 140         return (NULL);
 141 }
 142
 143 /*
 144  * Weak aliases for applications that use certain private entry points,
 145  * and fail to include <arpa/inet.h>.
 146  */
 147 #undef inet_net_ntop
 148 __weak_reference(__inet_net_ntop, inet_net_ntop);