enchostetherfilter.cc

COPE the first practical network coding scheme which is developped on click

/*
 * enchostetherfilter.{cc,hh} -- Discard packets not for this host.
 * Wenjun Hu
 *
 * adapted from hostetherfilter by Robert Morris
 *
 * Copyright (c) 2005 Massachusetts Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, subject to the conditions
 * listed in the Click LICENSE file. These conditions include: you must
 * preserve this copyright notice, and you cannot mention the copyright
 * holders in advertising related to the Software without their permission.
 * The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
 * notice is a summary of the Click LICENSE file; the license in that file is
 * legally binding.
 */

#include <click/config.h>
#include <click/confparse.hh>
#include <click/error.hh>
#include <click/glue.hh>
#include <click/etheraddress.hh>
#include <clicknet/ether.h>
#include "xorheader_general.hh"
#include "enchostetherfilter.hh"
CLICK_DECLS

EncHostEtherFilter::EncHostEtherFilter()
  :  HostEtherFilter(),
     _myea(),
     _aliases(0),
     _myalias(0)
     //_arp_table(0)
{
}

EncHostEtherFilter::~EncHostEtherFilter()
{
}

/*
void
HostEtherFilter::notify_noutputs(int n)
{
  set_noutputs(n < 2 ? 1 : 2);
}
*/

int
EncHostEtherFilter::configure(Vector<String> &conf, ErrorHandler *errh)
{
  bool drop_own = false, drop_other = true;
  
  int ret = cp_va_parse(conf, this, errh,
			cpKeywords,
			"ETH", cpEthernetAddress, "Ethernet address", &_myea,
			"ALIASTABLE", cpElement, "Alias Table", &_aliases,
			cpOptional,
			cpKeywords,
			"DROP_OWN", cpBool, "Drop packets from us?", &drop_own,
			"DROP_OTHER", cpBool, "Drop packets to others?", &drop_other,
			cpEnd);

  if (!_myea)
    return errh->error("ETH not specified");

  if (!_aliases)
    return errh->error("ALIASTABLE not specified");
  if (_aliases->cast("AliasTable") == 0)
    return errh->error("ALIASTABLE element is not an AliasTable");

  _drop_own = drop_own;
  _drop_other = drop_other;

  _myalias = _aliases->lookup(_myea);
  click_chatter("enchostfilter lookup");
  
  return ret;
}


Packet *
EncHostEtherFilter::drop(Packet *p)
{
  if (noutputs() == 2)
    output(1).push(p);
  else
    p->kill();
  return 0;
}


Packet *
EncHostEtherFilter::simple_action(Packet *p)
{
  click_ether *e = (click_ether *) p->data();
  unsigned short *daddr = (unsigned short *)e->ether_dhost;

  struct click_xorn_header *xorh = (struct click_xorn_header *)(e + 1);

  click_chatter("%s packet length %d", id().cc(), p->length());
  if (_drop_own && memcmp(e->ether_shost, _myea.data(), 6) == 0)
    return drop(p);
  else if (memcmp(e->ether_dhost, _myea.data(), 6) == 0) {
    p->set_packet_type_anno(Packet::HOST);
    click_chatter("%s packet meant for me", id().cc());
    return p;
  } else if (daddr[0] == 0xFFFF && daddr[1] == 0xFFFF && daddr[2] == 0xFFFF) {
    p->set_packet_type_anno(Packet::BROADCAST);
    return p;
  } else if (e->ether_dhost[0] & 0x80) {
    p->set_packet_type_anno(Packet::MULTICAST);
    return p;
  } else {
    // update the header with the 'right' ether address and decide further...
    // see scramblequeue.cc for how dest etheraddress of encoded packet is assigned
    // the current etheraddress should correspond to prev_hop[0]
    // so the alternative should be the other 
    // this might change in future...

    // brute force for now, could put into a loop later
    int nentries = xorh->nentries();
    click_chatter("%s coded packet", id().cc());
    for (int i = 0; i < nentries; i++) {
      if (xorh->get_entry_alias(i) == _myalias) {
        click_chatter("%s encoded packet meant for me", id().cc());
        p->set_packet_type_anno(Packet::HOST);
        memcpy(e->ether_dhost, _myea.data(), 6);
        return p;
      }
    }

//    if ((xorh->_alias[0] == _myalias) || (xorh->_alias[1] == _myalias)) {
//      p->set_packet_type_anno(Packet::HOST);
//      memcpy(e->ether_dhost, _myea.data(), 6);
//      return p;
//    } else {
    p->set_packet_type_anno(Packet::OTHERHOST);
    return (_drop_other ? drop(p) : p);
    /*
    EtherAddress dst = _arp_table->lookup(ip);
    EtherAddress alt_dst = _arp_table->lookup(alt_ip);

    // debugging
    click_chatter("%{element}: IP %s, MAC %s, IP %s, MAC %s", this, ip.s().cc(), dst.s().cc(), alt_ip.s().cc(), alt_dst.s().cc());

    // brute force...
    if (memcmp(_addr, dst.data(), 6) == 0) {
      p->set_packet_type_anno(Packet::HOST);
      memcpy(e->ether_dhost, dst.data(), 6);
      return p;
    } else if (memcmp(_addr, alt_dst.data(), 6) == 0) {
      p->set_packet_type_anno(Packet::HOST);
      memcpy(e->ether_dhost, alt_dst.data(), 6);
      return p;
    } else if (dst == _arp_table->_bcast) {
      click_chatter("%{element}::%s arp lookup failed for %s",
		    this,
		    __func__,
		    ip.s().cc());

      p->set_packet_type_anno(Packet::BROADCAST);
      return p;
    } else if (alt_dst == _arp_table->_bcast) {
      click_chatter("%{element}::%s arp lookup failed for %s",
		    this,
		    __func__,
		    alt_ip.s().cc());

      p->set_packet_type_anno(Packet::BROADCAST);
      return p;
    } else {
      p->set_packet_type_anno(Packet::OTHERHOST);
      return (_drop_other ? drop(p) : p);
    }

    
    memcpy(e->ether_dhost, alt_dst.data(), 6);

    if (alt_dst == _arp_table->_bcast) {
      click_chatter("%{element}::%s arp lookup failed for %s",
		    this,
		    __func__,
		    alt_ip.s().cc());

      p->set_packet_type_anno(Packet::BROADCAST);
      return p;
    } else if (memcmp(e->ether_dhost, _addr, 6) == 0){
      p->set_packet_type_anno(Packet::HOST);
      return p;
    } else {
      p->set_packet_type_anno(Packet::OTHERHOST);
      return (_drop_other ? drop(p) : p);
    }
    */
  }
}

CLICK_ENDDECLS
EXPORT_ELEMENT(EncHostEtherFilter)