Re: [ns] creation of a new agent

[Xuan Chen <xuanc@ISI.EDU>]

Please refer to Marc Greis' tutorial for the ping agent. Hope it helps,

-chen xuan

On Tue, 12 Jun 2001, fabio cappabianca wrote:

> 
> Hi all!
> 
> I use ns-2.1b6 in a linux Mandrake 8.0 platform.
> I try to create a new agent attached to node1 which simply sends packets
> with
> a regular interval to another agent attached to node2 which recv and
> simply
> discards the packets.
> I have also created a new packet header and modified the file: packet.h,
> ns-default,ns-packet,Makefile,cmu-trace.cc.
> 
> my problem is that when i run a simulation it gives me: SEGMENTATION
> FAULT
> 
> this is the code that i wrote, it is very simple but i don' t know why it
> doesn't work. Please help me
> 
> thanks in advance!
> 
> ****THIS IS THE TCL SCRIPT***********************************************
> set ns [new Simulator]
> set tracefd [open prova.tr w]
> $ns trace-all $tracefd
> 
> set n0 [$ns node]
> set n1 [$ns node]
> 
> $ns duplex-link $n0 $n1 1Mb 150ms DropTail
> 
> set pozzo [! ! new Agent/RXAGENT]
> $ns attach-agent $n1 $pozzo
> 
> 
> set sorgente [new Agent/NEWAGENT]
> $ns attach-agent $n0 $sorgente
> $sorgente set interval_ 0.3
> 
> $ns connect $sorgente $pozzo
> 
> $ns at 0.01 "$sorgente start_sending"
> $ns at 20 "$sorgente stoppa"
> $ns at 20.02 "puts \"NS EXITING ....\"; $ns halt"
> $ns at 20.01 "stop"
> 
> proc stop {} {
> global ns tracefd
> close $tracefd
> }
> 
> puts "Starting simulation... "
> $ns run
> *****************************************************************************
> ******************
> 
> THIS IS THE PACKET HEADER**********************************************
> #ifndef ns_packprova_h
> #define ns_packprova_h
> #include <stdlib.h>
> #include <string.h>
> #include "agent.h"
> #include "packet.h"
> #include "address.h"
> #include "ip! .h! "
> #include "timer-handler.h"
> #define SEND_TIME 0
> 
> typedef enum {DATAP} mytype;
> 
> struct hdr_packpr {
> ����� int seqnumber;
> ����� double delay;
> ����� mytype type;
> ����� static int offset_;
> ����� inline static int& offset() { return offset_; }
> ����� inline static hdr_packpr* access(Packet* p) {
> ����� ����� return (hdr_packpr*) p->access(offset_);
> }
> };
> #endif
> ******************************************************************! ****!
> *******
> *********************************
> 
> THIS IS THE AGENT THAT SEND PACKET (.H)
> #ifndef ns_newagent_h
> #define ns_newagent_h
> #include "packprova.h"
> 
> class newagent;
> 
> class SENDTIMER:public TimerHandler{
> public:
> SENDTIMER(newagent *a):TimerHandler(){a_=a;}
> protected:
> void expire(Event *e);
> newagent *a_;
> };
> 
> class newagent:public Agent{
> public:
> 
> newagent();
> void timeout(int);
> protected:
> 
> int command (int arcg, const char*const*argv);
> void send_data();
> double interval;
> int seq;
> int off_newp_;
> SENDTIMER send_timer;
> };
> #endif
> *****************************************************************************
> ********************* THIS IS THE AGENT THAT SEND PACKET (.CC)
> 
> #include "newagent.h"
> #include <iostream.h>
> int hdr_packpr::offset_;
> 
> static class NuovoheaderClass : public PacketHeaderClass{
> public:
> NuovoheaderClass(): PacketHeaderClass("Packe! tHeade!
> r/NEWP",sizeof(hdr_packpr))
> {
> ����������� ����������� ����� bind_offset(&hdr_packpr::offset_);
> ����� }
> }class_newhdr;
> 
> static class NEWAgentClass:public TclClass{
> public:
> NEWAgentClass():TclClass("Agent/NEWAGENT"){}
> TclObject* create(int,const char*const*){
> return(new newagent());
> }
> }class_NEWagent;
> 
> newagent::newagent():Agent(PT_NEWP),send_timer(this),seq(0){
> bind_time("interval_",&interval);
> bind("off_newp_",&off_newp_);
> }
> 
> void newagent::send_data(){
> Packet *p=allocpkt();
> hdr_packpr *hdrp=(hdr_packpr*)p->access(off_newp_);
> hdrp->type=DATAP;
> hdrp->seqnumber=++seq;
> hdr! p->de! lay=Scheduler::instance().clock();
> send(p,0);
> }
> 
> void SENDTIMER::expire(Event *e){
> a_->timeout(SEND_TIME);
> }
> 
> void newagent::timeout(int tno){
> switch(tno){
> case SEND_TIME:
> {
> send_data();
> send_timer.resched(interval);
> }
> }
> }
> 
> int newagent::command(int argc,const char*const*argv){
> if(argc==2){
> if (strcmp(argv[1],"start_sending")==0){
> timeout(SEND_TIME);
> return (TCL_OK);
> }
> if (strcmp(argv[1],"stoppa")==0){
> send_timer.cancel();
> return (TCL_OK);
> }
> }
> return(Agent::command(argc,argv));
> }
> *****************************************************************************
> ************************************** THIS IS THE AGENT THAT RECV THE
> PACKET
> �(.H)
> #ifndef ns_rxagent_h
> #define ns_rxagent_h
> 
> #include "packprova.h"
> 
> class rxagent:public Agent{
> public:
> 
> rxagent();
> void recv(Packet*,Handler*);
> int off_n! ewp_;
> }! ;
> 
> *****************************************************************************
> ******************* THIS IS THE AGENT THAT RECV THE PACKET (.CC)
> 
> #endif
> #include "rxagent.h"
> #include "iostream.h"
> 
> static class NuovoheaderClass : public PacketHeaderClass{
> public:
> NuovoheaderClass():
> PacketHeaderClass("PacketHeader/NEWP",sizeof(hdr_packpr))
> {
> ����������� ����������� ����� bind_offset(&hdr_packpr::offset_);
> ����� }
> }class_newhdr;
> 
> 
> static class RXAgentClass:public TclClass{
> public:
> RXAgentClass():TclClass("Agent/RXAGENT"){}
> TclObject* create(int,const char*const*){
> return(new rxagent());}
> }class! _RXagent;
> 
> rxagent::rxagent():Agent(PT_NEWP){
> bind("off_newp_",&off_newp_);
> }
> 
> void rxagent::recv(Packet *p,Handler*){
> hdr_packpr *hdrp=(hdr_packpr*)p->access(off_newp_);
> cout<<"numero di sequenza del pacchetto: " << hdrp->seqnumber << endl;
> double time=Scheduler::instance().clock();
> double t=time-hdrp->delay;
> cout << " ritardo nell'attraversare la rete : "<< t << endl;
> Packet::free(p);
> }
> 
> -------------------------------------------------------
> 
> -------------------------------------------------------
> 
> 
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> 

-- 
Xuan Chen
USC/ISI