Add a benchmark script.

This script sets up two network namespaces connected via a veth tunnel with
the netem qdisc to simulate "realistic" network conditions.

It first uses socat to transmit data via regular TCP, then transmits the
same amount of data using the UTCP test program. It prints the time it took
for both methods, and stores a packet trace for both methods so it can be
analyzed.

diff --git a/benchmark b/benchmark
new file mode 100755 (executable)
index 0000000..9b7e67d
--- /dev/null
+++ b/benchmark
@@ -0,0 +1,74 @@
+#!/bin/bash
+set -e
+
+# Configuration
+LOG_PREFIX=/dev/shm/benchmark-log
+SIZE=10000000
+RATE=100mbit
+DELAY=10ms
+JITTER=0ms
+
+# Require root permissions
+if [ "$USER" != "root" ]; then
+       exec sudo "$0" "$@"
+fi
+
+# Clean up old namespaces
+ip link del utcp-left 2>/dev/null || true
+ip link del utcp-right 2>/dev/null || true
+ip netns delete utcp-left 2>/dev/null || true
+ip netns delete utcp-right 2>/dev/null || true
+
+# Set up the left namespace
+ip netns add utcp-left
+ip link add name utcp-left type veth peer name utcp-right
+ip link set utcp-left netns utcp-left
+
+ip netns exec utcp-left ethtool -K utcp-left tso off
+ip netns exec utcp-left ip link set dev lo up
+ip netns exec utcp-left ip addr add dev utcp-left 192.168.1.1/24
+ip netns exec utcp-left ip link set utcp-left up
+
+#ip netns exec utcp-left tc qdisc del dev utcp-left root
+ip netns exec utcp-left tc qdisc add dev utcp-left root netem rate $RATE delay $DELAY $JITTER
+
+# Set up the right namespace
+ip netns add utcp-right
+ip link set utcp-right netns utcp-right
+
+ip netns exec utcp-right ethtool -K utcp-right tso off
+ip netns exec utcp-right ip link set dev lo up
+ip netns exec utcp-right ip addr add dev utcp-right 192.168.1.2/24
+ip netns exec utcp-right ip link set utcp-right up
+
+#ip netns exec utcp-right tc qdisc del dev utcp-right root
+ip netns exec utcp-right tc qdisc add dev utcp-right root netem rate $RATE delay $DELAY $JITTER
+
+# Test using kernel TCP
+ip netns exec utcp-right tcpdump -i utcp-right -w $LOG_PREFIX-socat.pcap port 9999 2>/dev/null &
+ip netns exec utcp-left socat TCP4-LISTEN:9999 - >/dev/null &
+sleep 0.1
+head -c $SIZE /dev/zero | ip netns exec utcp-right time socat - TCP4:192.168.1.1:9999 2>$LOG_PREFIX-socat-client.txt >/dev/null
+sleep 0.1
+kill $(jobs -p) 2>/dev/null
+
+# Test using UTCP
+ip netns exec utcp-right tcpdump -i utcp-right -w $LOG_PREFIX-utcp.pcap udp port 9999 2>/dev/null &
+ip netns exec utcp-left ./test 9999 2>$LOG_PREFIX-server.txt >/dev/null &
+sleep 0.1
+head -c $SIZE /dev/zero | ip netns exec utcp-right time ./test 192.168.1.1 9999 2>$LOG_PREFIX-client.txt >/dev/null
+sleep 0.1
+kill $(jobs -p) 2>/dev/null
+
+# Print timing statistics
+echo "Regular TCP:"
+tail -2 $LOG_PREFIX-socat-client.txt
+
+echo
+echo "UTCP:"
+tail -2 $LOG_PREFIX-client.txt
+
+# If sudo was used, ensure the log files can be read by the user
+if [ -n "$SUDO_USER" ]; then
+       chown $SUDO_USER $LOG_PREFIX-*
+fi