classifier-bst.cc

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/* -*-  Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */

/*
 * Copyright (C) 1999 by the University of Southern California
 * $Id: classifier-bst.cc,v 1.15 2005/08/25 18:58:01 johnh Exp $
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * 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.
 *
 *
 * The copyright of this module includes the following
 * linking-with-specific-other-licenses addition:
 *
 * In addition, as a special exception, the copyright holders of
 * this module give you permission to combine (via static or
 * dynamic linking) this module with free software programs or
 * libraries that are released under the GNU LGPL and with code
 * included in the standard release of ns-2 under the Apache 2.0
 * license or under otherwise-compatible licenses with advertising
 * requirements (or modified versions of such code, with unchanged
 * license).  You may copy and distribute such a system following the
 * terms of the GNU GPL for this module and the licenses of the
 * other code concerned, provided that you include the source code of
 * that other code when and as the GNU GPL requires distribution of
 * source code.
 *
 * Note that people who make modified versions of this module
 * are not obligated to grant this special exception for their
 * modified versions; it is their choice whether to do so.  The GNU
 * General Public License gives permission to release a modified
 * version without this exception; this exception also makes it
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 */

#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/classifier/classifier-bst.cc,v 1.15 2005/08/25 18:58:01 johnh Exp $";
#endif

#include <assert.h>
#include <stdlib.h>

#include "config.h"
#include "packet.h"
#include "ip.h"
#include "classifier.h"
#include "classifier-mcast.h"
#include "address.h"
#include "trace.h"
#include "ump.h"

struct upstream_info {
    int dst;
    int node_id;
    char* oiflink;
    struct upstream_info* next;
};

class MCastBSTClassifier : public MCastClassifier {
public:
    MCastBSTClassifier();
    ~MCastBSTClassifier();
    static const char STARSYM[]; //"source" field for shared trees
protected:
    virtual int classify(Packet * p);
    upstream_info *oif2RP_;
    int32_t node_id_;

    void insert_upstream_info(int dst);
    virtual void recv(Packet *p, Handler *h);
    void upstream_add(int dst, char *oif2RP, int node_id);
    upstream_info* upstream_find(int dst);
};


const char MCastBSTClassifier::STARSYM[]= "x"; //"source" field for shared trees

static class MCastBSTClassifierClass : public TclClass {
public:
    MCastBSTClassifierClass() : TclClass("Classifier/Multicast/BST") {}
    TclObject* create(int, const char*const*) {
        return (new MCastBSTClassifier());
    }
} class_mcast_bidir_classifier;

MCastBSTClassifier::MCastBSTClassifier()
{
    oif2RP_ = NULL;
    node_id_ = -1;
}

MCastBSTClassifier::~MCastBSTClassifier()
{
    clearAll();
}

int MCastBSTClassifier::classify(Packet *pkt)
{
    hdr_cmn* h = hdr_cmn::access(pkt);
    hdr_ip* ih = hdr_ip::access(pkt);

    nsaddr_t src = ih->saddr(); /*XXX*/
    nsaddr_t dst = ih->daddr();

    int iface = h->iface();
    Tcl& tcl = Tcl::instance();

    hashnode* p = lookup(src, dst, iface);
    //printf("%s, src %d, dst %d, iface %d, p %d\n", name(), src, dst, iface, p);
    if (p == 0)
            p = lookup_star(dst, iface);
        
    if (p == 0) {
        if ((p = lookup(src, dst)) == 0)
            p = lookup_star(dst);
        if (p == 0) {
            // Didn't find an entry.
            tcl.evalf("%s new-group %ld %ld %d cache-miss", 
                  name(), src, dst, iface);
            // XXX see McastProto.tcl for the return values 0 -
            // once, 1 - twice 
            //printf("cache-miss result= %s\n", tcl.result());
            int res= atoi(tcl.result());

            if (res)
                insert_upstream_info(dst);
            return (res)? Classifier::TWICE : Classifier::ONCE;
        }
        if (p->iif == ANY_IFACE.value()) // || iface == UNKN_IFACE.value())
            return p->slot;

        tcl.evalf("%s new-group %ld %ld %d wrong-iif", 
              name(), src, dst, iface);
        //printf("wrong-iif result= %s\n", tcl.result());
        int res= atoi(tcl.result());
        return (res)? Classifier::TWICE : Classifier::ONCE;
    }
    return p->slot;
}


void MCastBSTClassifier::recv(Packet *p, Handler *h) 
{
    hdr_cmn* h_cmn = hdr_cmn::access(p);
    hdr_ip* ih = hdr_ip::access(p);
    hdr_ump* ump = hdr_ump::access(p);
    nsaddr_t dst = ih->daddr();
    Tcl& tcl = Tcl::instance();
    upstream_info *u_info;

    if (node_id_ == -1) {
        tcl.evalf("[%s set node_] id", name());
        sscanf(tcl.result(), "%d", &node_id_);
    } // if

    nsaddr_t src = ih->saddr(); /*XXX*/

    NsObject *node = find(p);
    if (node == NULL) {
        Packet::free(p);
        return;
    } // if

    if ((node_id_ != src) && (ump->isSet) && (ump->umpID_ != node_id_)) {
        // If this node is not the next hop upstream router,
        // and if there are no receivers connected to it, then 
        // we should immediately drop the packet before we
        // trigger a chace miss
        int rpf_iface;

        tcl.evalf("%s check-rpf-link %d %d", name(), node_id_, dst);
        sscanf(tcl.result(), "%d", &rpf_iface);
        if (rpf_iface != h_cmn->iface()) {
            // The RPF check has failed so we have to drop
            // the packet.  Otherwise, we will create
            // duplicate packets on the net.
            Packet::free(p);
            return;

            // The following code demonstrates how we
            // could generate duplicates if RPF check is
            // ignord.  Do not reset the UMP and then we
            // will have even more duplicates.  Remember
            // to comment out the previous two lines

//              ih->flowid()++;
        } else 
            ump->isSet = 0;
    } // if

    if (src == node_id_) {
        memset(ump, 0, sizeof(hdr_ump)); // Initialize UMP to 0
        // We need to set the UMP option.  We need to find the
        // next hop router to the source and place it in the
        // UMP option.
        u_info = upstream_find(dst);
        if (!u_info) {
            printf("Error: Mcast info does not exist\n");
            exit(0);
        } // if
        ump->isSet = 1;
        ump->umpID_ = node_id_;
    } // if

//  if (ump->isSet) {
//      if (ump->umpID_ != node_id_) {
//          // By now we are sure that the packet has
//          // arrived on an RPF link.  So the UMP portion 
//          // of the packet should be cleared before it
//          // is sent downstream
//          ump->isSet = 0;
//      } // if
//  } // if

    if (ump->isSet) {
        u_info = upstream_find(dst);
        if (node_id_ == u_info->node_id)
            // If the next hop is the node itself, then we
            // are at the RP.
            ump->isSet = 0;
        else {
            ump->umpID_ = u_info->node_id;
            ump->oif = strdup(u_info->oiflink);
        } // else
    } else {
        int match;
        
        tcl.evalf("%s match-BST-iif %d %d", name(),
              h_cmn->iface(), dst);  
        sscanf(tcl.result(), "%d", (int *)&match);
        if (!match) {
            Packet::free(p);
            return;
        } // else
    } // else

    node->recv(p, h);
} // MCastBSTClassifier::recv

void MCastBSTClassifier::upstream_add(int dst, char *link, int node_id)
{
    struct upstream_info *next,
        *current;

    if (oif2RP_) {
        next = oif2RP_;
        do {
            current = next;
            if (current->dst == dst) {
                free(current->oiflink);
                current->oiflink = strdup(link);
                current->node_id = node_id;
                return;
            } // if
            next = current->next;
        } while (next);
        next = new(struct upstream_info);
        next->dst = dst;
        next->oiflink = strdup(link);
        next->node_id = node_id;
        current->next = next;
    } else {
        oif2RP_ = new(struct upstream_info);
        oif2RP_->dst = dst;
        oif2RP_->oiflink = strdup(link);
        oif2RP_->node_id = node_id;
        oif2RP_->next = NULL;
    } // else
} // MCastBSTClassifier::upstream_add

upstream_info* MCastBSTClassifier::upstream_find(int dst)
{
    upstream_info *index;

    index = oif2RP_;
    while (index) {
        if (index->dst == dst)
            return index;
        index = index->next;
    } // while
    return NULL;
} // MCastBSTClassifier::upstream_find

void MCastBSTClassifier::insert_upstream_info(int dst) 
{
    char temp_str[100];
    int nodeID;
    Tcl& tcl = Tcl::instance();

    tcl.evalf("%s info class", name());
    sscanf(tcl.result(), "%s", temp_str);
    tcl.evalf("%s upstream-link %d", name(), dst);
    sscanf(tcl.result(), "%s %d", temp_str, &nodeID);
    upstream_add(dst, temp_str, nodeID);
} // MCastBSTClassifier::insert_upstream_info

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