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#
# pingdemo.tcl
#
# demonstration of the emulation facilities using the icmp
# echo responder (also uses the arp responder)
#
# K Fall, 10/11/98
# kfall@cs.berkeley.edu
#
# Instructions:
# 1> first compile 'nse', the ns simulator with emulation
# 2> change the 'myname' var below to the name of some machine
# that isn't being used right now,
# and set ifname to the relevant interface
# 3> run this script (nse pingdemo.tcl)
# 4> run a 'ping' from some host to the name chosen in step 2
# 5> ping output should indicate the various functions exercised by
# the tests below
#
Class PingDemo
PingDemo instproc init {} {
$self next
$self instvar myname myaddr dotrace stoptime owdelay ifname delay_list next_delay_list
$self instvar traceallfile tracenamfile
#
# These parameters are system specific.
#
switch [exec hostname] {
pollytto* {
set myname "dash-w.isi.edu"
set ifname cnw0
set dotrace 0
}
kfalls-host* {
set myname "bit.ee.lbl.gov"
set ifname fxp0
set dotrace 1
}
default {
puts "error: running on an unknown host; edit PingDemo::init"
exit 1
}
}
set myaddr [exec host $myname | sed "s/.*address\ //"]
set stoptime 200.0
set owdelay 1000ms
set delay_list {0.5 0.1 0.01 0.001}
set next_delay_list ""
set traceallfile em-all.tr
set tracenamfile em.nam
puts ""
}
PingDemo instproc syssetup {} {
puts "turning off IP forwarding and ICMP redirect generation."
exec sysctl -w net.inet.ip.forwarding=0 net.inet.ip.redirect=0
}
PingDemo instproc emsetup {} {
$self instvar myname myaddr dotrace stoptime owdelay ifname
$self instvar traceallfile tracenamfile ns
puts "I am $myname with IP address $myaddr."
set ns [new Simulator]
if { $dotrace } {
exec rm -f $traceallfile $tracenamfile
set allchan [open $traceallfile w]
$ns trace-all $allchan
set namchan [open $tracenamfile w]
$ns namtrace-all $namchan
}
$ns use-scheduler RealTime
set bpf2 [new Network/Pcap/Live]; # used to read IP info
$bpf2 set promisc_ true
set dev2 [$bpf2 open readonly $ifname]
set ipnet [new Network/IP]; # used to write IP pkts
$ipnet open writeonly
set arpagent [new ArpAgent]
$arpagent config $ifname
set myether [$arpagent set myether_]
puts "Arranging to proxy ARP for $myaddr on my ethernet $myether."
$arpagent insert $myaddr $myether publish
#
# try to filter out unwanted stuff like netbios pkts, dns, etc
#
$bpf2 filter "icmp and dst $myaddr"
set pfa1 [new Agent/Tap]
set pfa2 [new Agent/Tap]
set ipa [new Agent/Tap]
set echoagent [new Agent/PingResponder]
$pfa2 set fid_ 0
$ipa set fid_ 1
$pfa2 network $bpf2
$ipa network $ipnet
#
# topology creation
#
set node0 [$ns node]
set node1 [$ns node]
set node2 [$ns node]
$ns simplex-link $node0 $node1 1Mb $owdelay DropTail
$ns simplex-link $node1 $node0 1Mb $owdelay DropTail
$ns simplex-link $node0 $node2 1Mb $owdelay DropTail
$ns simplex-link $node2 $node0 1Mb $owdelay DropTail
$ns simplex-link $node1 $node2 1Mb $owdelay DropTail
$ns simplex-link $node2 $node1 1Mb $owdelay DropTail
$self instvar explink1 explink2; # link to experiment with
set explink1 [$ns link $node0 $node2]
set explink2 [$ns link $node2 $node1]
#
# attach-agent winds up calling $node attach $agent which does
# these things:
# append agent to list of agents in the node
# sets target in the agent to the entry of the node
# sets the node_ field of the agent to the node
# if not yet created,
# create port demuxer in node (Addr classifier),
# put in dmux_
# call "$self add-route $id_ $dmux_"
# installs id<->dmux mapping in classifier_
# allocate a port
# set agent's port id and address
# install port-agent mapping in dmux_
#
#
$ns attach-agent $node0 $pfa2; # packet filter agent
$ns attach-agent $node1 $ipa; # ip agent (for sending)
$ns attach-agent $node2 $echoagent
$ns simplex-connect $pfa2 $echoagent
$ns simplex-connect $echoagent $ipa
}
PingDemo instproc newowdelay delay {
$self instvar explink1 explink2 ns owdelay
set owdelay $delay
set lnk [$explink1 link]
puts "[$ns now]: change 1-way delay from [$lnk set delay_] to $delay sec."
$lnk set delay_ $delay
set lnk [$explink2 link]
$lnk set delay_ $delay
}
# eternally cycle through the delays in delay_list
PingDemo instproc newowdelay_cycle {} {
$self instvar delay_list next_delay_list
if { "$next_delay_list" == "" } {
set next_delay_list $delay_list
}
set next_delay [lindex $next_delay_list 0]
set next_delay_list [lrange $next_delay_list 1]
$self newowdelay $next_delay
$ns at [expr [$ns now] + 10] "$self newowdelay_cycle"
}
PingDemo instproc run {} {
$self instvar ns myaddr owdelay ifname explink
$self syssetup
$self emsetup
puts "listening for pings on addr $myaddr, 1-way link delay: $owdelay\n"
$ns at 10.5 "$self newowdelay_cycle"
$ns run
}
PingDemo thisdemo
thisdemo run
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