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
2 | class AODV: public Agent { |
7 | double PerHopTime(aodv_rt_entry *rt); |
add following line
With this variable we are trying to define if the node is malicious or not. In
aodv.cc after
4 | AODV::AODV(nsaddr_t id) : Agent(PT_AODV),btimer(this), htimer(this), ntimer(this), rtimer(this), lrtimer(this), rqueue() { |
add following line
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
2 | Tcl& tcl = Tcl::instance(); |
4 | if(strncasecmp(argv[1], "id", 2) == 0) { |
5 | tcl.resultf("%d", index); |
add following line
1 | if(strcmp(argv[1], "hacker") == 0) { |
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 |
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
5 | AODV::rt_resolve(Packet *p) { |
6 | struct hdr_cmn *ch = HDR_CMN(p); |
7 | struct hdr_ip *ih = HDR_IP(p); |
We add a few lines
2 | if (malicious == true ) { |
3 | drop(p, DROP_RTR_ROUTE_LOOP); |
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,
