resolv/inet_neta.c

   1 /*
   2  * Copyright (c) 1996,1999 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 #include <sys/types.h>
  19 #include <sys/socket.h>
  20 #include <netinet/in.h>
  21 #include <arpa/inet.h>
  22
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26
  27 #ifdef SPRINTF_CHAR
  28 # define SPRINTF(x) strlen(sprintf/**/x)
  29 #else
  30 # define SPRINTF(x) ((size_t)sprintf x)
  31 #endif
  32
  33 /*
  34  * char *
  35  * inet_neta(src, dst, size)
  36  *      format a u_long network number into presentation format.
  37  * return:
  38  *      pointer to dst, or NULL if an error occurred (check errno).
  39  * note:
  40  *      format of ``src'' is as for inet_network().
  41  * author:
  42  *      Paul Vixie (ISC), July 1996
  43  */
  44 char *
  45 inet_neta (u_int32_t src, char *dst, size_t size)
  46 {
  47         char *odst = dst;
  48         char *tp;
  49
  50         while (src & 0xffffffff) {
  51                 u_char b = (src & 0xff000000) >> 24;
  52
  53                 src <<= 8;
  54                 if (b) {
  55                         if (size < sizeof "255.")
  56                                 goto emsgsize;
  57                         tp = dst;
  58                         dst += SPRINTF((dst, "%u", b));
  59                         if (src != 0L) {
  60                                 *dst++ = '.';
  61                                 *dst = '\0';
  62                         }
  63                         size -= (size_t)(dst - tp);
  64                 }
  65         }
  66         if (dst == odst) {
  67                 if (size < sizeof "0.0.0.0")
  68                         goto emsgsize;
  69                 strcpy(dst, "0.0.0.0");
  70         }
  71         return (odst);
  72
  73  emsgsize:
  74         __set_errno (EMSGSIZE);
  75         return (NULL);
  76 }