/*      $NetBSD: get.c,v 1.8 2024/12/03 05:57:02 kalvisd Exp $  */

/*
* Copyright (c) 1993-95 Mats O Jansson.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#if defined (HAVE_NBTOOL_CONFIG_H)
# include "nbtool_config.h"
#else
# include "port.h"
#endif /* defined (HAVE_NBTOOL_CONFIG_H) */
#ifndef lint
__RCSID("$NetBSD: get.c,v 1.8 2024/12/03 05:57:02 kalvisd Exp $");
#endif

#include "os.h"
#include "get.h"
#include "mopdef.h"

u_char
mopGetChar(const u_char *pkt, int *idx)
{
       u_char ret;

       ret = pkt[*idx];
       *idx = *idx + 1;
       return(ret);
}

u_short
mopGetShort(const u_char *pkt, int *idx)
{
       u_short ret;

       ret = pkt[*idx] + pkt[*idx+1]*256;
       *idx = *idx + 2;
       return(ret);
}

u_int32_t
mopGetLong(const u_char *pkt, int *idx)
{
       u_int32_t ret;

       ret = pkt[*idx] +
             pkt[*idx+1]*0x100 +
             pkt[*idx+2]*0x10000 +
             pkt[*idx+3]*0x1000000;
       *idx = *idx + 4;
       return(ret);
}

void
mopGetMulti(const u_char *pkt, int *idx, u_char *dest, int size)
{
       int i;

       for (i = 0; i < size; i++) {
         dest[i] = pkt[*idx+i];
       }
       *idx = *idx + size;

}

int
mopGetTrans(const u_char *pkt, int trans)
{
       const u_short   *ptype;

       if (trans == 0) {
               ptype = (const u_short *)(pkt+12);
               if (ntohs(*ptype) < 1600) {
                       trans = TRANS_8023;
               } else {
                       trans = TRANS_ETHER;
               }
       }
       return(trans);
}

void
mopGetHeader(const u_char *pkt, int *idx, const u_char **dst, const u_char **src,
            u_short *proto, int *len, int trans)
{
       *dst = pkt;
       *src = pkt + 6;
       *idx = *idx + 12;

       switch(trans) {
       case TRANS_ETHER:
               *proto = (u_short)(pkt[*idx]*256 + pkt[*idx+1]);
               *idx = *idx + 2;
               *len   = (int)(pkt[*idx+1]*256 + pkt[*idx]);
               *idx = *idx + 2;
               break;
       case TRANS_8023:
               *len   = (int)(pkt[*idx]*256 + pkt[*idx+1]);
               *idx = *idx + 8;
               *proto = (u_short)(pkt[*idx]*256 + pkt[*idx+1]);
               *idx = *idx + 2;
               break;
       }
}

u_short
mopGetLength(const u_char *pkt, int trans)
{
       switch(trans) {
       case TRANS_ETHER:
               return(pkt[15]*256 + pkt[14]);
               break;
       case TRANS_8023:
               return(pkt[12]*256 + pkt[13]);
               break;
       }
       return(0);
}