问题
How can I simulate a packet be dropped from a malicious node in a wireless network using ns2?
回答1:
First you need to modify aodv.cc and aodv.h files. In aodv.h after
/* The Routing Agent */
class AODV: public Agent {
...
/*
* History management
*/
double PerHopTime(aodv_rt_entry *rt);
...
add following line
bool malicious;
With this variable we are trying to define if the node is malicious or not. In aodv.cc after
/*
Constructor
*/
AODV::AODV(nsaddr_t id) : Agent(PT_AODV),btimer(this), htimer(this), ntimer(this), rtimer(this), lrtimer(this), rqueue() {
index = id;
seqno = 2;
bid = 1;
...
add following line
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
if(argc == 2) {
Tcl& tcl = Tcl::instance();
if(strncasecmp(argv[1], "id", 2) == 0) {
tcl.resultf("%d", index);
return TCL_OK;
}
add following line
if(strcmp(argv[1], "hacker") == 0) {
malicious = true;
return TCL_OK;
}
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.
$ns at 0.0 "[$mnode_(5) set ragent_] hacker"
You may add this line after
for {set i 0} {$i < $val(nn)} { incr i } {
$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
/*
Route Handling Functions
*/
void
AODV::rt_resolve(Packet *p) {
struct hdr_cmn *ch = HDR_CMN(p);
struct hdr_ip *ih = HDR_IP(p);
aodv_rt_entry *rt;
...
We add a few lines
// if I am malicious node
if (malicious == true ) {
drop(p, DROP_RTR_ROUTE_LOOP);
// DROP_RTR_ROUTE_LOOP is added for no reason.
}
And implementing malicious node is done. I hope the post will be helpful to design your secure routing protocol.
refer below link
http://elmurod.net/en/index.php/archives/196
来源：https://stackoverflow.com/questions/5261983/simulating-packet-dropping-in-a-wireless-network