root/trunk/src/headers_mgmt.c @ 12

/*
 * File: headers_mgmt.c
 * 
 * Authors: ANDREU François-Xavier 
 *
 * Copyright (C) 2005 GIP RENATER 
 */

/*  This file is part of renetcol. 
 *
 *  renetcol is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  renetcol is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with renetcol; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <stdlib.h>
#include "headers_mgmt.h"

/*
 * get IP Header
 */
unsigned short 
getIpHeader(DatagramPtr pcktPtr, unsigned char * buf)
{
  unsigned char buffer2[2];
  unsigned char buffer4[4];  
  unsigned short offset = 0;
  pcktPtr->ipH->versionAndLength = (unsigned short)*(buf);
  pcktPtr->ipH->tos = (unsigned short)*(buf+offset+1);
  buffer2[1]= *(buf+offset+2);
  buffer2[0]= *(buf+offset+3);
  pcktPtr->ipH->length = *((unsigned short*)&buffer2);
  buffer2[1]= *(buf+offset+4);
  buffer2[0]= *(buf+offset+5);
  pcktPtr->ipH->ident = *((unsigned short*)&buffer2);
  pcktPtr->ipH->flagsAndOffset = (unsigned short)(*(buf+offset+7));
  pcktPtr->ipH->ttl = (unsigned short)*(buf+offset+8);
  pcktPtr->ipH->protocol = (unsigned short)*(buf+offset+9);
  buffer2[1]= *(buf+offset+10);
  buffer2[0]= *(buf+offset+11);
  pcktPtr->ipH->checksum = *((unsigned short*)(&buffer2));
  buffer4[3] = *(buf+offset+12)&0xff;
  buffer4[2] = *(buf+offset+13)&0xff;
  buffer4[1] = *(buf+offset+14)&0xff;
  buffer4[0] = *(buf+offset+15)&0xff;
  pcktPtr->ipH->srcAdd = *((unsigned long*)(&buffer4));
  buffer4[3] = *(buf+offset+16)&0xff;
  buffer4[2] = *(buf+offset+17)&0xff;
  buffer4[1] = *(buf+offset+18)&0xff;
  buffer4[0] = *(buf+offset+19)&0xff;
  pcktPtr->ipH->dstAdd = *((unsigned long*)(&buffer4));
  return(0);
}

/*
 * few check on IP Header
 */
unsigned short 
checkIpHeader(DatagramPtr pP, unsigned long *sortedRLPtr, int rNb)
{
  if ((pP->ipH->versionAndLength>>4) != 4)
    {
      syslog(LOG_INFO,"IP version not 4 (%d)", (pP->ipH->versionAndLength>>4));
      return(1);
    }
/*   if (pckt.ipH.length_entete != 5) */
/*     { */
/*       syslog(LOG_INFO,"IHL != 5 (%d)", pckt.ipH.versionAndLength); */
/*       return(1); */
/*     }  */
  if (pP->ipH->tos != 0)
    {
      syslog(LOG_INFO,"TOS(%d) != 0",
              pP->ipH->tos);
    }
  if (pP->ipH->length > 1492)
    {
      syslog(LOG_INFO,"IP packet length > 1492 (%d)",
              pP->ipH->length);
      return(1);
    }
  if (pP->ipH->protocol != 17)
    {
      syslog(LOG_INFO,"Not UDP  protocol (%u)",pP->ipH->protocol);
      return(1);
    }
  if (bsearch(&pP->ipH->srcAdd, sortedRLPtr, rNb, sizeof(unsigned long),
              longCmp) == NULL ) 
    {
      return(2);
    }
  return(0);
}


/* 
 * get UDP Header
 */
unsigned short 
getUdpHeader(DatagramPtr pckt, unsigned char * ptr_buffer)
{
  unsigned char buffer2[2];
  unsigned short offset = 20;
  buffer2[1]= *(ptr_buffer+offset+0);
  buffer2[0]= *(ptr_buffer+offset+1);
  pckt->udp_header->srcPort = *((unsigned short*)&buffer2);
  buffer2[1]= *(ptr_buffer+offset+2);
  buffer2[0]= *(ptr_buffer+offset+3);
  pckt->udp_header->dstPort = *((unsigned short*)&buffer2);
  buffer2[1]= *(ptr_buffer+offset+4);
  buffer2[0]= *(ptr_buffer+offset+5);
  pckt->udp_header->length = *((unsigned short*)&buffer2);
  buffer2[1]= *(ptr_buffer+offset+6);
  buffer2[0]= *(ptr_buffer+offset+7);
  pckt->udp_header->checksum = *((unsigned short*)&buffer2);
  return(0);
}


/* 
 * few check on UDP Header
 */
unsigned short 
checkUdpHeader(DatagramPtr pckt, int regRouter, unsigned short receptPort )
{
  if(pckt->udp_header->dstPort != receptPort)
    {
      if (regRouter == 0){
        syslog(LOG_INFO,"Wrong destination port (%u)",
               pckt->udp_header->dstPort);
        return (1);
      }
      return (1);
    }else{
      if (regRouter == 2)
        {
          syslog(LOG_INFO,"Router Address not registered : %lu.%lu.%lu.%lu)",
                 (pckt->ipH->srcAdd>>24),
                 (pckt->ipH->srcAdd<<8>>24),
                 (pckt->ipH->srcAdd<<16>>24),
                 (pckt->ipH->srcAdd<<24>>24));
          return (1);
        }
      return (0);
    }
/*   if(pckt->udp_header->length > 1472) */
/*     { */
/*       syslog(LOG_INFO,"UDP length > 1472"); */
/*       return(1); */
/*     } */
  return(0);
}