Some small fixups and rearrangements to previous commit (#732)

Signed-off-by: Andy Fingerhut <andy_fingerhut@alum.wustl.edu>

Author: jafingerhut

.github/workflows/test-exercises.yml

@@ -31,7 +31,6 @@ jobs:
       - name: Run PTF Tests
         run: |
           cd exercises/basic
-          mkdir -p logs
           make test
         # Retain logs in case runs fail
       - name: Upload Logs

bin/veth_setup.sh

@@ -0,0 +1,44 @@
+#!/bin/bash
+# SPDX-License-Identifier: Apache-2.0
+# Copyright 2017 Andy Fingerhut
+
+# This script was originally copied from the location below, then
+# modified:
+#
+# https://github.com/p4lang/behavioral-model/blob/master/tools/veth_setup.sh
+
+for idx in 0 1 2 3 4 5 6 7 8; do
+    intf0="veth$(($idx*2))"
+    intf1="veth$(($idx*2+1))"
+    if ! ip link show $intf0 &> /dev/null; then
+        ip link add name $intf0 type veth peer name $intf1
+        ip link set dev $intf0 up
+        ip link set dev $intf1 up
+
+        # Set the MTU of these interfaces to be larger than default of
+        # 1500 bytes, so that P4 behavioral-model testing can be done
+        # on jumbo frames.
+        ip link set $intf0 mtu 9500
+        ip link set $intf1 mtu 9500
+	############################################################
+	# ifconfig is deprecated, and no longer installed by default
+	# in Ubuntu Linux minimal installs starting with Ubuntu 18.04
+	# LTS.
+	#ifconfig $intf0 mtu 9500 up
+	#ifconfig $intf1 mtu 9500 up
+	############################################################
+
+        # Disable IPv6 on the interfaces, so that the Linux kernel
+        # will not automatically send IPv6 MDNS, Router Solicitation,
+        # and Multicast Listener Report packets on the interface,
+        # which can make P4 program debugging more confusing.
+        #
+        # Testing indicates that we can still send IPv6 packets across
+        # such interfaces, both from scapy to simple_switch, and from
+        # simple_switch out to scapy sniffing.
+        #
+        # https://superuser.com/questions/356286/how-can-i-switch-off-ipv6-nd-ra-transmissions-in-linux
+        sysctl -q net.ipv6.conf.${intf0}.disable_ipv6=1
+        sysctl -q net.ipv6.conf.${intf1}.disable_ipv6=1
+    fi
+done

bin/veth_teardown.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+# SPDX-License-Identifier: Apache-2.0
+# Copyright 2019 Andy Fingerhut
+#
+
+# This script was copied from the location below, for convenience of
+# p4-guide users:
+#
+# https://github.com/p4lang/behavioral-model/blob/master/tools/veth_teardown.sh
+
+for idx in 0 1 2 3 4 5 6 7 8; do
+    intf="veth$(($idx*2))"
+    if ip link show $intf &> /dev/null; then
+        ip link delete $intf type veth
+    fi
+done

exercises/basic/Makefile

@@ -4,5 +4,5 @@ TOPO = pod-topo/topology.json
 
 include ../../utils/Makefile
 
-test:
+test: dirs
 	./runptf.sh

exercises/basic/runptf.sh

@@ -3,20 +3,9 @@
 # Tests run against the solution P4 program.
 
 set -e
+BINDIR=$(realpath ../../bin)
 
-# ---- veth setup ----
-echo "Creating veth interfaces..."
-for i in 0 1 2 3 4 5 6 7; do
-    intf0="veth$(( i * 2 ))"
-    intf1="veth$(( i * 2 + 1 ))"
-    if ! ip link show $intf0 &>/dev/null; then
-        sudo ip link add name $intf0 type veth peer name $intf1
-        sudo ip link set dev $intf0 up
-        sudo ip link set dev $intf1 up
-        sudo sysctl -q net.ipv6.conf.$intf0.disable_ipv6=1
-        sudo sysctl -q net.ipv6.conf.$intf1.disable_ipv6=1
-    fi
-done
+sudo "${BINDIR}"/veth_setup.sh
 
 set -x
 
@@ -71,12 +60,7 @@ sudo pkill --signal 9 --list-name simple_switch
 
 echo ""
 echo "Cleaning up veth interfaces..."
-for i in 0 1 2 3 4 5 6 7; do
-    intf0="veth$(( i * 2 ))"
-    if ip link show $intf0 &>/dev/null; then
-        sudo ip link del $intf0
-    fi
-done
+sudo "${BINDIR}"/veth_teardown.sh
 
 echo ""
 echo "Verifying no simple_switch_grpc processes remain..."