lib/libc/net/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  * $FreeBSD: src/lib/libc/net/inet_net_ntop.c,v 1.5 1999/08/28 00:00:10 peter Exp $
  18  * $DragonFly: src/lib/libc/net/inet_net_ntop.c,v 1.4 2005/11/13 02:04:47 swildner Exp $
  19  */
  20
  21 #include <sys/types.h>
  22 #include <sys/socket.h>
  23 #include <netinet/in.h>
  24 #include <arpa/inet.h>
  25
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <stdlib.h>
  30
  31 #ifdef SPRINTF_CHAR
  32 # define SPRINTF(x) strlen(sprintf/**/x)
  33 #else
  34 # define SPRINTF(x) ((size_t)sprintf x)
  35 #endif
  36
  37 static char *   inet_net_ntop_ipv4 (const u_char *src, int bits,
  38                                         char *dst, size_t size);
  39
  40 /*
  41  * char *
  42  * inet_net_ntop(af, src, bits, dst, size)
  43  *      convert network number from network to presentation format.
  44  *      generates CIDR style result always.
  45  * return:
  46  *      pointer to dst, or NULL if an error occurred (check errno).
  47  * author:
  48  *      Paul Vixie (ISC), July 1996
  49  */
  50 char *
  51 inet_net_ntop(int af, const void *src, int bits, char *dst, size_t size)
  52 {
  53         switch (af) {
  54         case AF_INET:
  55                 return (inet_net_ntop_ipv4(src, bits, dst, size));
  56         default:
  57                 errno = EAFNOSUPPORT;
  58                 return (NULL);
  59         }
  60 }
  61
  62 /*
  63  * static char *
  64  * inet_net_ntop_ipv4(src, bits, dst, size)
  65  *      convert IPv4 network number from network to presentation format.
  66  *      generates CIDR style result always.
  67  * return:
  68  *      pointer to dst, or NULL if an error occurred (check errno).
  69  * note:
  70  *      network byte order assumed.  this means 192.5.5.240/28 has
  71  *      0x11110000 in its fourth octet.
  72  * author:
  73  *      Paul Vixie (ISC), July 1996
  74  */
  75 static char *
  76 inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)
  77 {
  78         char *odst = dst;
  79         char *t;
  80         u_int m;
  81         int b;
  82
  83         if (bits < 0 || bits > 32) {
  84                 errno = EINVAL;
  85                 return (NULL);
  86         }
  87         if (bits == 0) {
  88                 if (size < sizeof "0")
  89                         goto emsgsize;
  90                 *dst++ = '0';
  91                 *dst = '\0';
  92         }
  93
  94         /* Format whole octets. */
  95         for (b = bits / 8; b > 0; b--) {
  96                 if (size < sizeof "255.")
  97                         goto emsgsize;
  98                 t = dst;
  99                 dst += SPRINTF((dst, "%u", *src++));
 100                 if (b > 1) {
 101                         *dst++ = '.';
 102                         *dst = '\0';
 103                 }
 104                 size -= (size_t)(dst - t);
 105         }
 106
 107         /* Format partial octet. */
 108         b = bits % 8;
 109         if (b > 0) {
 110                 if (size < sizeof ".255")
 111                         goto emsgsize;
 112                 t = dst;
 113                 if (dst != odst)
 114                         *dst++ = '.';
 115                 m = ((1 << b) - 1) << (8 - b);
 116                 dst += SPRINTF((dst, "%u", *src & m));
 117                 size -= (size_t)(dst - t);
 118         }
 119
 120         /* Format CIDR /width. */
 121         if (size < sizeof "/32")
 122                 goto emsgsize;
 123         dst += SPRINTF((dst, "/%u", bits));
 124         return (odst);
 125
 126  emsgsize:
 127         errno = EMSGSIZE;
 128         return (NULL);
 129 }
 130
 131 /*
 132  * Weak aliases for applications that use certain private entry points,
 133  * and fail to include <arpa/inet.h>.
 134  */
 135 #undef inet_net_ntop
 136 __weak_reference(__inet_net_ntop, inet_net_ntop);