usr.sbin/mopd/common/get.c

   1 /*      $NetBSD: get.c,v 1.5 2009/10/20 00:51:13 snj Exp $      */
   2
   3 /*
   4  * Copyright (c) 1993-95 Mats O Jansson.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 #ifndef lint
  29 __RCSID("$NetBSD: get.c,v 1.5 2009/10/20 00:51:13 snj Exp $");
  30 #endif
  31
  32 #include "os.h"
  33 #include "get.h"
  34 #include "mopdef.h"
  35
  36 u_char
  37 mopGetChar(const u_char *pkt, int *idx)
  38 {
  39         u_char ret;
  40
  41         ret = pkt[*idx];
  42         *idx = *idx + 1;
  43         return(ret);
  44 }
  45
  46 u_short
  47 mopGetShort(const u_char *pkt, int *idx)
  48 {
  49         u_short ret;
  50
  51         ret = pkt[*idx] + pkt[*idx+1]*256;
  52         *idx = *idx + 2;
  53         return(ret);
  54 }
  55
  56 u_int32_t
  57 mopGetLong(const u_char *pkt, int *idx)
  58 {
  59         u_int32_t ret;
  60
  61         ret = pkt[*idx] +
  62               pkt[*idx+1]*0x100 +
  63               pkt[*idx+2]*0x10000 +
  64               pkt[*idx+3]*0x1000000;
  65         *idx = *idx + 4;
  66         return(ret);
  67 }
  68
  69 void
  70 mopGetMulti(const u_char *pkt, int *idx, u_char *dest, int size)
  71 {
  72         int i;
  73
  74         for (i = 0; i < size; i++) {
  75           dest[i] = pkt[*idx+i];
  76         }
  77         *idx = *idx + size;
  78
  79 }
  80
  81 int
  82 mopGetTrans(const u_char *pkt, int trans)
  83 {
  84         const u_short   *ptype;
  85
  86         if (trans == 0) {
  87                 ptype = (const u_short *)(pkt+12);
  88                 if (ntohs(*ptype) < 1600) {
  89                         trans = TRANS_8023;
  90                 } else {
  91                         trans = TRANS_ETHER;
  92                 }
  93         }
  94         return(trans);
  95 }
  96
  97 void
  98 mopGetHeader(const u_char *pkt, int *idx, const u_char **dst, const u_char **src,
  99              u_short *proto, int *len, int trans)
 100 {
 101         *dst = pkt;
 102         *src = pkt + 6;
 103         *idx = *idx + 12;
 104
 105         switch(trans) {
 106         case TRANS_ETHER:
 107                 *proto = (u_short)(pkt[*idx]*256 + pkt[*idx+1]);
 108                 *idx = *idx + 2;
 109                 *len   = (int)(pkt[*idx+1]*256 + pkt[*idx]);
 110                 *idx = *idx + 2;
 111                 break;
 112         case TRANS_8023:
 113                 *len   = (int)(pkt[*idx]*256 + pkt[*idx+1]);
 114                 *idx = *idx + 8;
 115                 *proto = (u_short)(pkt[*idx]*256 + pkt[*idx+1]);
 116                 *idx = *idx + 2;
 117                 break;
 118         }
 119 }
 120
 121 u_short
 122 mopGetLength(const u_char *pkt, int trans)
 123 {
 124         switch(trans) {
 125         case TRANS_ETHER:
 126                 return(pkt[15]*256 + pkt[14]);
 127                 break;
 128         case TRANS_8023:
 129                 return(pkt[12]*256 + pkt[13]);
 130                 break;
 131         }
 132         return(0);
 133 }