click-align.cc

Click is a modular router toolkit. To use it you ll need to know how to compile and install the sof

inline String
aligner_name(int anonymizer)
{
  return String("Align@click_align@") + String(anonymizer);
}

int
main(int argc, char **argv)
{
  click_static_initialize();
  CLICK_DEFAULT_PROVIDES;
  ErrorHandler *errh = ErrorHandler::default_handler();
  PrefixErrorHandler p_errh(errh, "click-align: ");

  // read command line arguments
  Clp_Parser *clp =
    Clp_NewParser(argc, argv, sizeof(options) / sizeof(options[0]), options);
  Clp_SetOptionChar(clp, '+', Clp_ShortNegated);
  program_name = Clp_ProgramName(clp);

  const char *router_file = 0;
  bool file_is_expr = false;
  const char *output_file = 0;

  while (1) {
    int opt = Clp_Next(clp);
    switch (opt) {

     case HELP_OPT:
      usage();
      exit(0);
      break;

     case VERSION_OPT:
      printf("click-align (Click) %s\n", CLICK_VERSION);
      printf("Copyright (C) 1999-2000 Massachusetts Institute of Technology\n\
Copyright (C) 2007 Regents of the University of California\n\
This is free software; see the source for copying conditions.\n\
There is NO warranty, not even for merchantability or fitness for a\n\
particular purpose.\n");
      exit(0);
      break;

     case ROUTER_OPT:
     case EXPRESSION_OPT:
     router_file:
      if (router_file) {
	errh->error("router configuration specified twice");
	goto bad_option;
      }
      router_file = clp->vstr;
      file_is_expr = (opt == EXPRESSION_OPT);
      break;

      case USERLEVEL_OPT:
      case LINUXMODULE_OPT:
      case BSDMODULE_OPT:
	if (specified_driver >= 0) {
	    errh->error("driver specified twice");
	    goto bad_option;
	}
	specified_driver = opt - FIRST_DRIVER_OPT;
	break;

     case Clp_NotOption:
      if (!click_maybe_define(clp->vstr, errh))
	  goto router_file;
      break;

     case OUTPUT_OPT:
      if (output_file) {
	errh->error("output file specified twice");
	goto bad_option;
      }
      output_file = clp->vstr;
      break;

     bad_option:
     case Clp_BadOption:
      short_usage();
      exit(1);
      break;

     case Clp_Done:
      goto done;

    }
  }

  done:
    // read router
    ElementClassT::set_base_type_factory(class_factory);
    RouterT *router = read_router(router_file, file_is_expr, errh);
    if (router)
	router->flatten(errh);
    if (!router || errh->nerrors() > 0)
	exit(1);

    // get element map and processing
    element_map.parse_all_files(router, CLICK_DATADIR, &p_errh);

    // we know that Classifier requires alignment.  If the element map does
    // not, complain loudly.
    if (!element_map.has_traits("Classifier")) {
	p_errh.warning("elementmap has no information for Classifier, muddling along");
	p_errh.message("(This is usually because of a missing 'elementmap.xml'.\nYou may get errors when running this configuration.)");
	const char *classes[] = { "Classifier", "IPClassifier", "IPFilter", "CheckIPHeader", "CheckIPHeader2", "UDPIPEncap", "IPInputCombo", 0 };
	for (const char **sp = classes; *sp; ++sp) {
	    ElementTraits t = element_map.traits(*sp);
	    t.flags += "A";
	    element_map.add(t);
	}
    }

    // decide on a driver
    if (specified_driver >= 0) {
	if (!element_map.driver_compatible(router, specified_driver))
	    errh->warning("configuration not compatible with %s driver", Driver::name(specified_driver));
	element_map.set_driver_mask(1 << specified_driver);
    } else {
	int driver_mask = 0;
	for (int d = 0; d < Driver::COUNT; d++)
	    if (element_map.driver_compatible(router, d))
		driver_mask |= 1 << d;
	if (driver_mask == 0)
	    errh->warning("configuration not compatible with any driver");
	else
	    element_map.set_driver_mask(driver_mask);
    }

    // correct classes for router
    //correct_classes(driver_mask);

    ElementClassT *align_class = ElementClassT::base_type("Align");
    assert(align_class);

    int original_nelements = router->nelements();
    int anonymizer = original_nelements + 1;
    while (router->eindex(aligner_name(anonymizer)) >= 0)
	anonymizer++;

    /*
     * Add Align elements for required alignments
     */
    int num_aligns_added = 0;
    {
	// calculate current alignment
	RouterAlign ral(router, errh);
	do {
	    ral.have_output();
	} while (ral.have_input());

	// calculate desired alignment
	RouterAlign want_ral(router, errh);
	do {
	    want_ral.want_input();
	} while (want_ral.want_output());

	// add required aligns
	for (int i = 0; i < original_nelements; i++)
	    for (int j = 0; j < ral._icount[i]; j++) {
		Alignment have = ral._ialign[ ral._ioffset[i] + j ];
		Alignment want = want_ral._ialign[ ral._ioffset[i] + j ];
		if (have <= want || want.bad())
		    /* do nothing */;
		else {
		    ElementT *e = router->get_element
			(aligner_name(anonymizer), align_class,
			 String(want.modulus()) + ", " + String(want.offset()),
			 LandmarkT("<click-align>"));
		    router->insert_before(e, PortT(router->element(i), j));
		    anonymizer++;
		    num_aligns_added++;
		}
	    }
    }

    /*
     * remove duplicate Aligns (Align_1 -> Align_2)
     */
    {
	const Vector<ConnectionT> &conn = router->connections();
	int nhook = conn.size();
	for (int i = 0; i < nhook; i++)
	    if (conn[i].live() && conn[i].to_element()->type() == align_class
		&& conn[i].from_element()->type() == align_class) {
		// skip over hf[i]
		Vector<PortT> above, below;
		router->find_connections_to(conn[i].from(), above);
		router->find_connections_from(conn[i].from(), below);
		if (below.size() == 1) {
		    for (int j = 0; j < nhook; j++)
			if (conn[j].to() == conn[i].from())
			    router->change_connection_to(j, conn[i].to());
		} else if (above.size() == 1) {
		    for (int j = 0; j < nhook; j++)
			if (conn[j].to() == conn[i].to())
			    router->change_connection_from(j, above[0]);
		}
	    }
    }

    /*
     * Add Aligns required for adjustment alignments
     *
     * Classifier is an example: it can cope with any alignment that is
     * consistent and has a modulus >= 4. Rather than require a specific
     * alignment above, we handle Classifier here; required alignments may
     * have generated an alignment we can deal with.
     */
    {
	// calculate current alignment
	RouterAlign ral(router, errh);
	do {
	    ral.have_output();
	} while (ral.have_input());

	// calculate adjusted alignment
	RouterAlign want_ral(ral);
	want_ral.adjust();

	// add required aligns
	for (int i = 0; i < original_nelements; i++)
	    for (int j = 0; j < ral._icount[i]; j++) {
		Alignment have = ral._ialign[ ral._ioffset[i] + j ];
		Alignment want = want_ral._ialign[ ral._ioffset[i] + j ];
		if (have <= want || want.bad())
		    /* do nothing */;
		else {
		    ElementT *e = router->get_element
			(aligner_name(anonymizer), align_class,
			 String(want.modulus()) + ", " + String(want.offset()),
			 LandmarkT("<click-align>"));
		    router->insert_before(e, PortT(router->element(i), j));
		    anonymizer++;
		    num_aligns_added++;
		}
	    }
    }

    while (1) {
	// calculate current alignment
	RouterAlign ral(router, errh);
	do {
	    ral.have_output();
	} while (ral.have_input());

	bool changed = false;

	// skip redundant Aligns
	for (RouterT::conn_iterator ci = router->begin_connections();
	     ci != router->end_connections(); ++ci)
	    if (ci->live() && ci->to_element()->type() == align_class) {
		Alignment have = ral._oalign[ ral._ooffset[ci->from_eindex()] + ci->from_port() ];
		Alignment want = ral._oalign[ ral._ooffset[ci->to_eindex()] ];
		if (have <= want) {
		    changed = true;
		    Vector<PortT> align_dest;
		    router->find_connections_from(ci->to(), align_dest);
		    for (int j = 0; j < align_dest.size(); j++)
			router->add_connection(ci->from(), align_dest[j]);
		    router->kill_connection(ci);
		}
	    }

	if (!changed)
	    break;

	router->remove_duplicate_connections();
    }

    // remove unused Aligns (they have no input) and old AlignmentInfos
    ElementClassT *aligninfo_class = ElementClassT::base_type("AlignmentInfo");
    {
	for (RouterT::type_iterator x = router->begin_elements(aligninfo_class);
	     x != router->end_elements(); ++x)
	    x->full_kill();
	bool again;
	do {
	    again = false;
	    for (RouterT::type_iterator x = router->begin_elements(align_class);
		 x != router->end_elements(); ++x)
		if (x->ninputs() == 0 || x->noutputs() == 0) {
		    if (x->landmark() == "<click-align>")
			num_aligns_added--;
		    again = true;
		    x->full_kill();
		}
	} while (again);
	router->remove_dead_elements();
    }

    // make the AlignmentInfo element
    {
	RouterAlign ral(router, errh);
	do {
	    ral.have_output();
	} while (ral.have_input());

	// collect alignment information
	StringAccum sa;
	for (RouterT::iterator x = router->begin_elements(); x; x++) {
	    ElementTraits t = element_map.traits(x->type_name());
	    if (x->ninputs() && t.flag_value('A') > 0) {
		if (sa.length())
		    sa << ",\n  ";
		sa << x->name();
		int i = x->eindex();
		for (int j = 0; j < ral._icount[i]; j++) {
		    const Alignment &a = ral._ialign[ ral._ioffset[i] + j ];
		    sa << "  " << a.modulus() << " " << a.offset();
		}
	    }
	}

	if (sa.length())
	    router->get_element(String("AlignmentInfo@click_align@")
				+ String(anonymizer),
				aligninfo_class, sa.take_string(),
				LandmarkT("<click-align>"));
    }

  // warn if added aligns
  if (num_aligns_added > 0)
    errh->warning((num_aligns_added > 1 ? "added %d Align elements" : "added %d Align element"), num_aligns_added);

  // write result
  if (write_router_file(router, output_file, errh) < 0)
    exit(1);
  return 0;
}