/* * ackresponder.{cc,hh} -- element sends link-level ACKs * Douglas S. J. De Couto * * Copyright (c) 2002 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/glue.hh>#include <clicknet/ether.h>#include <click/confparse.hh>#include <click/packet.hh>#include "ackresponder.hh"CLICK_DECLSACKResponder::ACKResponder() : Element(1, 2){}ACKResponder::~ACKResponder(){}Packet *ACKResponder::simple_action(Packet *p){  click_ether *e = (click_ether *) p->data();  EtherAddress dest(e->ether_dhost);  if (dest == _eth) {    WritablePacket *xp = Packet::make(sizeof(click_ether) + 2); // +2 to align ether hdr    xp->pull(2);    click_ether *eth = (click_ether *) xp->data();    eth->ether_type = htons(ETHERTYPE_GRID_ACK);    memcpy(eth->ether_shost, e->ether_dhost, 6);    memcpy(eth->ether_dhost, e->ether_shost, 6);    output(1).push(xp);  }  return p;}intACKResponder::configure(Vector<String> &conf, ErrorHandler *errh){  return cp_va_parse(conf, this, errh,		     cpEthernetAddress, "our Ethernet address", &_eth,		     cpEnd);}CLICK_ENDDECLSEXPORT_ELEMENT(ACKResponder)