arp.c

/*! \file "arp.c" \brief Implementation of the arp protocol */
///	\ingroup network
///	\defgroup ARP ARP-Funktionen (arp.c)
///	\code #include "arp.h" \endcode
///	\code #include "ip.h" \endcode
///	\code #include "ethernet.h" \endcode
///	\par Uebersicht
//****************************************************************************/
/*
 *  This program 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.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
//@{
#include <stdio.h>
#include <stdlib.h>

#include "config.h"
#include "arp.h"
#include "ethernet.h"
#include "eemem.h"
#include "enc28j60.h"


struct ARP_TABLE ARPtable[ MAX_ARP_ENTRY ];

//----------------------------------------------------------------------------
//Diese Routine Antwortet auf ein ARP Paket
void arp_reply (void)
{
	struct ETH_header *ETH_packet;
	struct ARP_header *ARP_packet;

	ETH_packet = (struct ETH_header *)ethernetbuffer;
	ARP_packet      = (struct ARP_header *)&ethernetbuffer[ETH_HDR_LEN];
	
    if(ARP_packet->ARP_destIP == mlIP) // Für uns?
    {
		uint8_t i;
        if (ARP_packet->ARP_Opcode == 0x0100) // htons(0x0001)   // Request?
        {
            arp_entry_add(ARP_packet->ARP_sourceIP, ARP_packet->ARP_sourceMac); 
            Make_ETH_Header (ethernetbuffer, ARP_packet->ARP_sourceIP); // Erzeugt ein neuen Ethernetheader
            ETH_packet->ETH_typefield = 0x0608; // htons(0x0806) Nutzlast 0x0800=IP Datagramm;0x0806 = ARP
      
			// mac und ip des senders in ziel kopieren
			for ( i = 0; i < 10; i++ )
				ARP_packet->ARP_destMac[i] = ARP_packet->ARP_sourceMac[i]; // MAC und IP umkopieren
			
			// meine mac und ip als absender einsetzen
			for ( i = 0; i < 6 ; i++ )
				ARP_packet->ARP_sourceMac[i] = mlMAC[i];
			
			ARP_packet->ARP_sourceIP = mlIP; // IP einsetzen
      
            ARP_packet->ARP_Opcode = 0x0200;	// htons(0x0002) ARP op = ECHO  
      
            ETH_PACKET_SEND(ARP_REPLY_LEN, ethernetbuffer);          // ARP Reply senden...
            return;
        }
        else if ( ARP_packet->ARP_Opcode == 0x0200 )  // htons(0x0002) REPLY von einem anderen Client
        {
            arp_entry_add(ARP_packet->ARP_sourceIP, ARP_packet->ARP_sourceMac);
        }
    }
    return;
}

//----------------------------------------------------------------------------
//erzeugt einen ARP - Eintrag wenn noch nicht vorhanden 
void arp_entry_add (unsigned long sourceIP, unsigned char *sourceMac)
{
    //Eintrag schon vorhanden?
	uint8_t i;
    for (i = 0; i < MAX_ARP_ENTRY; i++)
    {
		if(ARPtable[i].IP == sourceIP)
		{
			//Eintrag gefunden Time refresh
			ARPtable[i].time = ARP_MAX_ENTRY_TIME;
			return;
		}
    }
  
    //Freien Eintrag finden
    for (i = 0; i < MAX_ARP_ENTRY; i++)
    {
        if(ARPtable[i].IP == 0)
        {
			for(uint8_t a = 0; a < 6; a++)
			{
				ARPtable[i].MAC[a] = sourceMac[a]; 
			}
			ARPtable[i].IP   = sourceIP;
			ARPtable[i].time = ARP_MAX_ENTRY_TIME;
#if DEBUG_AV && DEBUG_ARP
	putpgmstring("arp_entry_add\r\n");
	puthexbyte(sourceIP>>0);
	puthexbyte(sourceIP>>8);
	puthexbyte(sourceIP>>16);
	puthexbyte(sourceIP>>24);
	putpgmstring("\r\n");
#endif
			return;
        }
    }
    return;
}


//----------------------------------------------------------------------------
//Diese Routine sucht anhand der IP den ARP eintrag
unsigned char *arp_entry_search (unsigned long dest_ip)
{
#if DEBUG_AV && DEBUG_ARP
	putpgmstring("arp_entry_search\r\n");
	puthexbyte(dest_ip>>0);
	puthexbyte(dest_ip>>8);
	puthexbyte(dest_ip>>16);
	puthexbyte(dest_ip>>24);
	putpgmstring("\r\n");
#endif	
	for (uint8_t i = 0; i < MAX_ARP_ENTRY; i++)
	{
		if(ARPtable[i].IP == dest_ip)
		{
			return ARPtable[i].MAC;
		}
	}
#if DEBUG_AV && DEBUG_ARP
	putpgmstring("arp_entry_search - FAILED\r\n");
#endif	
	return NULL;
}