From e5f721797d6113079eb306c2bb025c7a7928072a Mon Sep 17 00:00:00 2001
From: Lars Eggert <lars@eggert.org>
Date: Wed, 4 Sep 2024 23:27:22 -0700
Subject: [PATCH] use `tcpdump` to capture pcaps (#133)

* Use `tcpdump` to capture a second set of pcaps

* Don't capture pcaps with ns3
---
 sim/Dockerfile                                     | 2 +-
 sim/run.sh                                         | 2 ++
 sim/scenarios/helper/quic-point-to-point-helper.cc | 4 ----
 3 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/sim/Dockerfile b/sim/Dockerfile
index 52d02bb..18ccff0 100644
--- a/sim/Dockerfile
+++ b/sim/Dockerfile
@@ -38,7 +38,7 @@ RUN cd /wait-for-it-quic && go build .
 FROM ubuntu:24.04
 
 RUN apt-get update && \
-  apt-get install -y net-tools iptables libgsl-dev libxml2 libsqlite3-0 && \
+  apt-get install -y net-tools iptables libgsl-dev libxml2 libsqlite3-0 tcpdump && \
   apt-get clean
 
 WORKDIR /ns3
diff --git a/sim/run.sh b/sim/run.sh
index 9be56e6..ab50fe7 100644
--- a/sim/run.sh
+++ b/sim/run.sh
@@ -22,6 +22,8 @@ fi
 
 echo "Using scenario:" $SCENARIO
 
+tcpdump -i eth0 -U -w "/logs/trace_node_left.pcap" &
+tcpdump -i eth1 -U -w "/logs/trace_node_right.pcap" &
 eval ./scratch/"$SCENARIO &"
 
 PID=`jobs -p`
diff --git a/sim/scenarios/helper/quic-point-to-point-helper.cc b/sim/scenarios/helper/quic-point-to-point-helper.cc
index ed9bb5e..b04e063 100644
--- a/sim/scenarios/helper/quic-point-to-point-helper.cc
+++ b/sim/scenarios/helper/quic-point-to-point-helper.cc
@@ -16,10 +16,6 @@ void QuicPointToPointHelper::SetQueueSize(StringValue size) {
 
 NetDeviceContainer QuicPointToPointHelper::Install(Ptr<Node> a, Ptr<Node> b) {
   NetDeviceContainer devices = PointToPointHelper::Install(a, b);
-  // capture a pcap of all packets
-  EnablePcap("/logs/trace_node_left.pcap", devices.Get(0), false, true);
-  EnablePcap("/logs/trace_node_right.pcap", devices.Get(1), false, true);
-  
   TrafficControlHelper tch;
   tch.SetRootQueueDisc("ns3::PfifoFastQueueDisc", "MaxSize", queue_size_);
   tch.Install(devices);