For using promiscuous mode in AODV NS2

For using promiscuous mode in AODV NS2

Intro:-

          In Promiscuous mode each node in the network listens the packets transmitted by its own neighbor nodes. 

          In NS-2, some time we have to calculate the packet drops or analyze the process. For the same we need to set the network to operate in promiscuous mode. Here, I am going to explain how we can set our wireless network in promiscuous mode with AODV as Routing protocol using NS2 simulator.

1) We need to modify in total 3 files, so it's good to take a backup of it.
    Files are:

• ns-allinone-2.34/ns-2.34/aodv/aodv.cc
• ns-allinone-2.34/ns-2.34/aodv/aodv.h
• ns-allinone-2.34/ns-2.34/tcl/lib/ns-mobilenode.tcl

2) Open the file ns-allinone-2.34/ns-2.34/aodv/aodv.h in your favorite editor
    and make the changes as shown in blue color.

  #include <mac.h>

  class AODV: public Tap, public Agent {

  public:

  void tap(const Packet *p);

  ......

  protected:

  Mac *mac_;

  ......

 }

3) Open the file ns-allinone-2.34/ns-2.34/aodv/aodv.cc and make the changes as  

    shown in blue color.

int
AODV::command(int argc, const char* const * argv) {

......

else if(argc == 3) {

......

else if (strcmp(argv[1], "install-tap") == 0) {
mac_ = (Mac*)TclObject::lookup(argv[2]);
if (mac_ == 0) return TCL_ERROR;
mac_->installTap(this);
return TCL_OK;
}

}
return Agent::command(argc, argv);

}

void
AODV::tap(const Packet *p) {

// put your code here

} 

   

4) Open the file ns-allinone-2.34/ns-2.34/tcl/lib/ns-mobilenode.tcl and make the  

    changes as shown in blue color.

Node/MobileNode instproc add-target { agent port } {

$self instvar dmux_ imep_ toraDebug_ mac_

......

# Special processing for AODV
set aodvonly [string first "AODV" [$agent info class]]
if {$aodvonly != -1 } {
$agent if-queue [$self set ifq_(0)] ; # ifq between LL and MAC

$agent install-tap $mac_(0)

......

}

Explanation:-

         The above procedure will put all the nodes in the wireless network in promiscuous mode. If a node A wants to listen the packets from a node B in promiscuous mode to check whether to check B is forwarding the packets which are sent by A to B or not we can write the code in function tap()

5) To simulate a node as a malicious node in AODV see below (not yours but blogs)

Many people have asked me how to implement malicious drop in AODV. I have decided to write simple code for adding malicious node in AODV ( or in any routing protocol).
First you need to modify aodv.cc and aodv.h files. In aodv.h after

1	/*  The Routing Agent */

2	class AODV: public Agent {

3

...

4

/*

5	* History management

6

*/

7	double      PerHopTime(aodv_rt_entry *rt);

8

...

add following line

1	bool     malicious;

With this variable we are trying to define if the node is malicious or not. In aodv.cc after

1

/*

2	Constructor

3

*/

4	AODV::AODV(nsaddr_t id) : Agent(PT_AODV),btimer(this), htimer(this), ntimer(this), rtimer(this), lrtimer(this), rqueue() {

5	index = id;

6	seqno = 2;

7

bid = 1;

8

...

add following line

1	malicious = false;

The above code is needed to initialize, and all nodes are initially not malicious. Then we will write a code to catch which node is set as malicious. In aodv.cc after

1	if(argc == 2) {

2	Tcl& tcl = Tcl::instance();

3

4	if(strncasecmp(argv[1], "id", 2) == 0) {

5	tcl.resultf("%d", index);

6	return TCL_OK;

7

}

add following line

1	if(strcmp(argv[1], "hacker") == 0) {

2	malicious = true;

3	return TCL_OK;

4

}

Now we will do some work in TCL to set a malicious node. Using script in my post , we add following line to set node 5 as malicious node.

1	$ns at 0.0 "[$mnode_(5) set ragent_] hacker"

You may add this line after

1	for {set i 0} {$i < $val(nn)} { incr i } {

2	$ns initial_node_pos $mnode_($i) 10

3

}

4

...

Alright, we have set malicious node but we did not tell malicious node what to do. As it is known, rt_resolve(Packet *p) function is used to select next hop node when routing data packets. So, we tell malicious node just drop any packet when it receives. To do that after

1

/*

2	Route Handling Functions

3

*/

4

void

5	AODV::rt_resolve(Packet *p) {

6	struct hdr_cmn *ch = HDR_CMN(p);

7	struct hdr_ip *ih = HDR_IP(p);

8	aodv_rt_entry *rt;

9

...

We add a few lines

1	// if I am malicious node

2	if (malicious == true ) {

3	drop(p, DROP_RTR_ROUTE_LOOP);

4	// DROP_RTR_ROUTE_LOOP is added for no reason.

5

}

And implementing malicious node is done. I hope the post will be helpful to design your secure routing protocol.
P.S. Guys please don’t ask me c/c++ questions,