--- /dev/null
+Motivation
+==========
+
+One of the nice things about network namespaces is that they allow one
+to easily create and test complex environments.
+
+Unfortunately, these namespaces can not be used with actual switching
+ASICs, as their ports can not be migrated to other network namespaces
+(NETIF_F_NETNS_LOCAL) and most of them probably do not support the
+L1-separation provided by namespaces.
+
+However, a similar kind of flexibility can be achieved by using VRFs and
+by looping the switch ports together. For example:
+
+ br0
+ +
+ vrf-h1 | vrf-h2
+ + +---+----+ +
+ | | | |
+ 192.0.2.1/24 + + + + 192.0.2.2/24
+ swp1 swp2 swp3 swp4
+ + + + +
+ | | | |
+ +--------+ +--------+
+
+The VRFs act as lightweight namespaces representing hosts connected to
+the switch.
+
+This approach for testing switch ASICs has several advantages over the
+traditional method that requires multiple physical machines, to name a
+few:
+
+1. Only the device under test (DUT) is being tested without noise from
+other system.
+
+2. Ability to easily provision complex topologies. Testing bridging
+between 4-ports LAGs or 8-way ECMP requires many physical links that are
+not always available. With the VRF-based approach one merely needs to
+loopback more ports.
+
+These tests are written with switch ASICs in mind, but they can be run
+on any Linux box using veth pairs to emulate physical loopbacks.
+
+Guidelines for Writing Tests
+============================
+
+o Where possible, reuse an existing topology for different tests instead
+ of recreating the same topology.
+o Where possible, IPv6 and IPv4 addresses shall conform to RFC 3849 and
+ RFC 5737, respectively.
+o Where possible, tests shall be written so that they can be reused by
+ multiple topologies and added to lib.sh.
+o Checks shall be added to lib.sh for any external dependencies.
+o Code shall be checked using ShellCheck [1] prior to submission.
+
+1. https://www.shellcheck.net/
--- /dev/null
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+##############################################################################
+# Defines
+
+# Can be overridden by the configuration file.
+PING=${PING:=ping}
+PING6=${PING6:=ping6}
+WAIT_TIME=${WAIT_TIME:=5}
+PAUSE_ON_FAIL=${PAUSE_ON_FAIL:=no}
+PAUSE_ON_CLEANUP=${PAUSE_ON_CLEANUP:=no}
+
+if [[ -f forwarding.config ]]; then
+ source forwarding.config
+fi
+
+##############################################################################
+# Sanity checks
+
+if [[ "$(id -u)" -ne 0 ]]; then
+ echo "SKIP: need root privileges"
+ exit 0
+fi
+
+tc -j &> /dev/null
+if [[ $? -ne 0 ]]; then
+ echo "SKIP: iproute2 too old, missing JSON support"
+ exit 0
+fi
+
+if [[ ! -x "$(command -v jq)" ]]; then
+ echo "SKIP: jq not installed"
+ exit 0
+fi
+
+if [[ ! -v NUM_NETIFS ]]; then
+ echo "SKIP: importer does not define \"NUM_NETIFS\""
+ exit 0
+fi
+
+##############################################################################
+# Network interfaces configuration
+
+for i in $(eval echo {1..$NUM_NETIFS}); do
+ ip link show dev ${NETIFS[p$i]} &> /dev/null
+ if [[ $? -ne 0 ]]; then
+ echo "SKIP: could not find all required interfaces"
+ exit 0
+ fi
+done
+
+##############################################################################
+# Helpers
+
+# Exit status to return at the end. Set in case one of the tests fails.
+EXIT_STATUS=0
+# Per-test return value. Clear at the beginning of each test.
+RET=0
+
+check_err()
+{
+ local err=$1
+ local msg=$2
+
+ if [[ $RET -eq 0 && $err -ne 0 ]]; then
+ RET=$err
+ retmsg=$msg
+ fi
+}
+
+check_fail()
+{
+ local err=$1
+ local msg=$2
+
+ if [[ $RET -eq 0 && $err -eq 0 ]]; then
+ RET=1
+ retmsg=$msg
+ fi
+}
+
+log_test()
+{
+ local test_name=$1
+ local opt_str=$2
+
+ if [[ $# -eq 2 ]]; then
+ opt_str="($opt_str)"
+ fi
+
+ if [[ $RET -ne 0 ]]; then
+ EXIT_STATUS=1
+ printf "TEST: %-60s [FAIL]\n" "$test_name $opt_str"
+ if [[ ! -z "$retmsg" ]]; then
+ printf "\t%s\n" "$retmsg"
+ fi
+ if [ "${PAUSE_ON_FAIL}" = "yes" ]; then
+ echo "Hit enter to continue, 'q' to quit"
+ read a
+ [ "$a" = "q" ] && exit 1
+ fi
+ return 1
+ fi
+
+ printf "TEST: %-60s [PASS]\n" "$test_name $opt_str"
+ return 0
+}
+
+setup_wait()
+{
+ for i in $(eval echo {1..$NUM_NETIFS}); do
+ while true; do
+ ip link show dev ${NETIFS[p$i]} up \
+ | grep 'state UP' &> /dev/null
+ if [[ $? -ne 0 ]]; then
+ sleep 1
+ else
+ break
+ fi
+ done
+ done
+
+ # Make sure links are ready.
+ sleep $WAIT_TIME
+}
+
+pre_cleanup()
+{
+ if [ "${PAUSE_ON_CLEANUP}" = "yes" ]; then
+ echo "Pausing before cleanup, hit any key to continue"
+ read
+ fi
+}
+
+vrf_prepare()
+{
+ ip -4 rule add pref 32765 table local
+ ip -4 rule del pref 0
+ ip -6 rule add pref 32765 table local
+ ip -6 rule del pref 0
+}
+
+vrf_cleanup()
+{
+ ip -6 rule add pref 0 table local
+ ip -6 rule del pref 32765
+ ip -4 rule add pref 0 table local
+ ip -4 rule del pref 32765
+}
+
+__last_tb_id=0
+declare -A __TB_IDS
+
+__vrf_td_id_assign()
+{
+ local vrf_name=$1
+
+ __last_tb_id=$((__last_tb_id + 1))
+ __TB_IDS[$vrf_name]=$__last_tb_id
+ return $__last_tb_id
+}
+
+__vrf_td_id_lookup()
+{
+ local vrf_name=$1
+
+ return ${__TB_IDS[$vrf_name]}
+}
+
+vrf_create()
+{
+ local vrf_name=$1
+ local tb_id
+
+ __vrf_td_id_assign $vrf_name
+ tb_id=$?
+
+ ip link add dev $vrf_name type vrf table $tb_id
+ ip -4 route add table $tb_id unreachable default metric 4278198272
+ ip -6 route add table $tb_id unreachable default metric 4278198272
+}
+
+vrf_destroy()
+{
+ local vrf_name=$1
+ local tb_id
+
+ __vrf_td_id_lookup $vrf_name
+ tb_id=$?
+
+ ip -6 route del table $tb_id unreachable default metric 4278198272
+ ip -4 route del table $tb_id unreachable default metric 4278198272
+ ip link del dev $vrf_name
+}
+
+__addr_add_del()
+{
+ local if_name=$1
+ local add_del=$2
+ local array
+
+ shift
+ shift
+ array=("${@}")
+
+ for addrstr in "${array[@]}"; do
+ ip address $add_del $addrstr dev $if_name
+ done
+}
+
+simple_if_init()
+{
+ local if_name=$1
+ local vrf_name
+ local array
+
+ shift
+ vrf_name=v$if_name
+ array=("${@}")
+
+ vrf_create $vrf_name
+ ip link set dev $if_name master $vrf_name
+ ip link set dev $vrf_name up
+ ip link set dev $if_name up
+
+ __addr_add_del $if_name add "${array[@]}"
+}
+
+simple_if_fini()
+{
+ local if_name=$1
+ local vrf_name
+ local array
+
+ shift
+ vrf_name=v$if_name
+ array=("${@}")
+
+ __addr_add_del $if_name del "${array[@]}"
+
+ ip link set dev $if_name down
+ vrf_destroy $vrf_name
+}
+
+master_name_get()
+{
+ local if_name=$1
+
+ ip -j link show dev $if_name | jq -r '.[]["master"]'
+}
+
+##############################################################################
+# Tests
+
+ping_test()
+{
+ local if_name=$1
+ local dip=$2
+ local vrf_name
+
+ RET=0
+
+ vrf_name=$(master_name_get $if_name)
+ ip vrf exec $vrf_name $PING $dip -c 10 -i 0.1 -w 2 &> /dev/null
+ check_err $?
+ log_test "ping"
+}
+
+ping6_test()
+{
+ local if_name=$1
+ local dip=$2
+ local vrf_name
+
+ RET=0
+
+ vrf_name=$(master_name_get $if_name)
+ ip vrf exec $vrf_name $PING6 $dip -c 10 -i 0.1 -w 2 &> /dev/null
+ check_err $?
+ log_test "ping6"
+}