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Date:   Wed, 6 Jul 2022 19:20:59 +0200
From:   Andrea Mayer <andrea.mayer@uniroma2.it>
To:     Paolo Abeni <pabeni@redhat.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Shuah Khan <shuah@kernel.org>,
        Anton Makarov <anton.makarov11235@gmail.com>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        Stefano Salsano <stefano.salsano@uniroma2.it>,
        Paolo Lungaroni <paolo.lungaroni@uniroma2.it>,
        Ahmed Abdelsalam <ahabdels.dev@gmail.com>,
        Andrea Mayer <andrea.mayer@uniroma2.it>
Subject: Re: [net-next v4 3/4] selftests: seg6: add selftest for SRv6
 H.Encaps.Red behavior
Message-Id: <20220706192059.ef7a2d1daed663549b5a5b4f@uniroma2.it>
In-Reply-To: <78dbedad777bc10ad2310a1efd0c65bd69e1dc2b.camel@redhat.com>
References: <20220701150152.24103-1-andrea.mayer@uniroma2.it>
        <20220701150152.24103-4-andrea.mayer@uniroma2.it>
        <78dbedad777bc10ad2310a1efd0c65bd69e1dc2b.camel@redhat.com>
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Hi Paolo,
thanks for your time, please see below.

On Tue, 05 Jul 2022 09:48:53 +0200
Paolo Abeni <pabeni@redhat.com> wrote:

> On Fri, 2022-07-01 at 17:01 +0200, Andrea Mayer wrote:
> > This selftest is designed for testing the H.Encaps.Red behavior. It
> > instantiates a virtual network composed of several nodes: hosts and SRv6
> > routers. Each node is realized using a network namespace that is
> > properly interconnected to others through veth pairs.
> > The test considers SRv6 routers implementing L3 VPNs leveraged by hosts
> > for communicating with each other. Such routers make use of the SRv6
> > H.Encaps.Red behavior for applying SRv6 policies to L3 traffic coming
> > from hosts.
> > 
> > The correct execution of the behavior is verified through reachability
> > tests carried out between hosts belonging to the same VPN.
> > 
> > Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
> > ---
> >  tools/testing/selftests/net/Makefile          |   1 +
> >  .../net/srv6_hencap_red_l3vpn_test.sh         | 742 ++++++++++++++++++
> >  2 files changed, 743 insertions(+)
> >  create mode 100755 tools/testing/selftests/net/srv6_hencap_red_l3vpn_test.sh
> > 
> > diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> > index ddad703ace34..3b0e9bef196b 100644
> > --- a/tools/testing/selftests/net/Makefile
> > +++ b/tools/testing/selftests/net/Makefile
> > @@ -35,6 +35,7 @@ TEST_PROGS += cmsg_time.sh cmsg_ipv6.sh
> >  TEST_PROGS += srv6_end_dt46_l3vpn_test.sh
> >  TEST_PROGS += srv6_end_dt4_l3vpn_test.sh
> >  TEST_PROGS += srv6_end_dt6_l3vpn_test.sh
> > +TEST_PROGS += srv6_hencap_red_l3vpn_test.sh
> >  TEST_PROGS += vrf_strict_mode_test.sh
> >  TEST_PROGS += arp_ndisc_evict_nocarrier.sh
> >  TEST_PROGS += ndisc_unsolicited_na_test.sh
> > diff --git a/tools/testing/selftests/net/srv6_hencap_red_l3vpn_test.sh b/tools/testing/selftests/net/srv6_hencap_red_l3vpn_test.sh
> > new file mode 100755
> > index 000000000000..3b97f187b189
> > --- /dev/null
> > +++ b/tools/testing/selftests/net/srv6_hencap_red_l3vpn_test.sh
> > @@ -0,0 +1,742 @@
> > +#!/bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +#
> > +# author: Andrea Mayer <andrea.mayer@uniroma2.it>
> > +#
> > +# This script is designed for testing the SRv6 H.Encaps.Red behavior.
> > +#
> > +# Below is depicted the IPv6 network of an operator which offers advanced
> > +# IPv4/IPv6 VPN services to hosts, enabling them to communicate with each
> > +# other.
> > +# In this example, hosts hs-1 and hs-2 are connected through an IPv4/IPv6 VPN
> > +# service, while hs-3 and hs-4 are connected using an IPv6 only VPN.
> > +#
> > +# Routers rt-1,rt-2,rt-3 and rt-4 implement IPv4/IPv6 L3 VPN services
> > +# leveraging the SRv6 architecture. The key components for such VPNs are:
> > +#
> > +#   i) The SRv6 H.Encaps.Red behavior applies SRv6 Policies on traffic received
> > +#      by connected hosts, initiating the VPN tunnel. Such a behavior is an
> > +#      optimization of the SRv6 H.Encap aiming to reduce the length of the SID
> > +#      List carried in the pushed SRH. Specifically, the H.Encaps.Red removes
> > +#      the first SID contained in the SID List (i.e. SRv6 Policy) by storing it
> > +#      into the IPv6 Destination Address. When a SRv6 Policy is made of only one
> > +#      SID, the SRv6 H.Encaps.Red behavior omits the SRH at all and pushes that
> > +#      SID directly into the IPv6 DA;
> > +#
> > +#  ii) The SRv6 End behavior advances the active SID in the SID List carried by
> > +#      the SRH;
> > +#
> > +# iii) The SRv6 End.DT46 behavior is used for removing the SRv6 Policy and,
> > +#      thus, it terminates the VPN tunnel. Such a behavior is capable of
> > +#      handling, at the same time, both tunneled IPv4 and IPv6 traffic.
> > +#
> > +#
> > +#               cafe::1                      cafe::2
> > +#              10.0.0.1                     10.0.0.2
> > +#             +--------+                   +--------+
> > +#             |        |                   |        |
> > +#             |  hs-1  |                   |  hs-2  |
> > +#             |        |                   |        |
> > +#             +---+----+                   +--- +---+
> > +#    cafe::/64    |                             |      cafe::/64
> > +#  10.0.0.0/24    |                             |    10.0.0.0/24
> > +#             +---+----+                   +----+---+
> > +#             |        |  fcf0:0:1:2::/64  |        |
> > +#             |  rt-1  +-------------------+  rt-2  |
> > +#             |        |                   |        |
> > +#             +---+----+                   +----+---+
> > +#                 |      .               .      |
> > +#                 |  fcf0:0:1:3::/64   .        |
> > +#                 |          .       .          |
> > +#                 |            .   .            |
> > +# fcf0:0:1:4::/64 |              .              | fcf0:0:2:3::/64
> > +#                 |            .   .            |
> > +#                 |          .       .          |
> > +#                 |  fcf0:0:2:4::/64   .        |
> > +#                 |      .               .      |
> > +#             +---+----+                   +----+---+
> > +#             |        |                   |        |
> > +#             |  rt-4  +-------------------+  rt-3  |
> > +#             |        |  fcf0:0:3:4::/64  |        |
> > +#             +---+----+                   +----+---+
> > +#    cafe::/64    |                             |      cafe::/64
> > +#  10.0.0.0/24    |                             |    10.0.0.0/24
> > +#             +---+----+                   +--- +---+
> > +#             |        |                   |        |
> > +#             |  hs-4  |                   |  hs-3  |
> > +#             |        |                   |        |
> > +#             +--------+                   +--------+
> > +#               cafe::4                      cafe::3
> > +#              10.0.0.4                     10.0.0.3
> > +#
> > +#
> > +# Every fcf0:0:x:y::/64 network interconnects the SRv6 routers rt-x with rt-y
> > +# in the IPv6 operator network.
> > +#
> > +# Local SID table
> > +# ===============
> > +#
> > +# Each SRv6 router is configured with a Local SID table in which SIDs are
> > +# stored. Considering the given SRv6 router rt-x, at least two SIDs are
> > +# configured in the Local SID table:
> > +#
> > +#   Local SID table for SRv6 router rt-x
> > +#   +----------------------------------------------------------+
> > +#   |fcff:x:e is associated with the SRv6 End behavior         |
> > +#   |fcff:x:d46 is associated with the SRv6 End.DT46 behavior  |
> > +#   +----------------------------------------------------------+
> > +#
> > +# The fcff:/16 prefix is reserved by the operator for implementing SRv6 VPN
> > +# services. Reachability of SIDs is ensured by proper configuration of the IPv6
> > +# operator's network and SRv6 routers.
> > +#
> > +# # SRv6 Policies
> > +# ===============
> > +#
> > +# An SRv6 ingress router applies SRv6 policies to the traffic received from a
> > +# connected host. SRv6 policy enforcement consists of encapsulating the
> > +# received traffic into a new IPv6 packet with a given SID List contained in
> > +# the SRH.
> > +#
> > +# IPv4/IPv6 VPN between hs-1 and hs-2
> > +# -----------------------------------
> > +#
> > +# Hosts hs-1 and hs-2 are connected using dedicated IPv4/IPv6 VPNs.
> > +# Specifically, packets generated from hs-1 and directed towards hs-2 are
> > +# handled by rt-1 which applies the following SRv6 Policies:
> > +#
> > +#   i.a) IPv6 traffic, SID List=fcff:3::e,fcff:4::e,fcff:2::d46
> > +#  ii.a) IPv4 traffic, SID List=fcff:2::d46
> > +#
> > +# Policy (i.a) steers tunneled IPv6 traffic through SRv6 routers
> > +# rt-3,rt-4,rt-2. Instead, Policy (ii.b) steers tunneled IPv4 traffic through
> > +# rt-2.
> > +# The H.Encaps.Red reduces the SID List (i.a) carried in SRH by removing the
> > +# first SID (fcff:3::e) and pushing it into the IPv6 DA. In case of IPv4
> > +# traffic, the H.Encaps.Red omits the presence of SRH at all, since the SID
> > +# List (ii.a) consists of only one SID that can be stored directly in the IPv6
> > +# DA.
> > +#
> > +# On the reverse path (i.e. from hs-2 to hs-1), rt-2 applies the following
> > +# policies:
> > +#
> > +#   i.b) IPv6 traffic, SID List=fcff:1:d46
> > +#  ii.b) IPv4 traffic, SID List=fcff:4::e,fcff:3::e,fcff:1::d46
> > +#
> > +# Policy (i.b) steers tunneled IPv6 traffic through the SRv6 router rt-1.
> > +# Conversely, Policy (ii.b) steers tunneled IPv4 traffic through SRv6 routers
> > +# rt-4,rt-3,rt-1.
> > +# The H.Encaps.Red omits the SRH at all in case of (i.b) by pushing the single
> > +# SID (fcff::1:d46) inside the IPv6 DA.
> > +# The H.Encaps.Red reduces the SID List (ii.b) in the SRH by removing the first
> > +# SID (fcff:4::e) and pushing it into the IPv6 DA.
> > +#
> > +# In summary:
> > +#  * hs-1 -> hs-2 |IPv6 DA=fcff:3::e|SRH SIDs=fcff:4::e,fcff:2::d46|IPv6|...| (i.a)
> > +#  * hs-1 -> hs-2 |IPv6 DA=fcff:2::d46|IPv4|...|                              (ii.a)
> > +#
> > +#  * hs-2 -> hs-1 |IPv6 DA=fcff:1::d46|IPv6|...|                              (i.b)
> > +#  * hs-2 -> hs-1 |IPv6 DA=fcff:4::e|SRH SIDs=fcff:3::e,fcff:1::d46|IPv4|...| (ii.b)
> > +#
> > +#
> > +# IPv6 VPN between hs-3 and hs-4
> > +# ------------------------------
> > +#
> > +# Hosts hs-3 and hs-4 are connected using a dedicated IPv6 only VPN.
> > +# Specifically, packets generated from hs-3 and directed towards hs-4 are
> > +# handled by rt-3 which applies the following SRv6 Policy:
> > +#
> > +#  i.c) IPv6 traffic, SID List=fcff:2::e,fcff:4::d46
> > +#
> > +# Policy (i.c) steers tunneled IPv6 traffic through SRv6 routers rt-2,rt-4.
> > +# The H.Encaps.Red reduces the SID List (i.c) carried in SRH by pushing the
> > +# first SID (fcff:2::e) in the IPv6 DA.
> > +#
> > +# On the reverse path (i.e. from hs-4 to hs-3) the router rt-4 applies the
> > +# following SRv6 Policy:
> > +#
> > +#  i.d) IPv6 traffic, SID List=fcff:1::e,fcff:3::d46.
> > +#
> > +# Policy (i.d) steers tunneled IPv6 traffic through SRv6 routers rt-1,rt-3.
> > +# The H.Encaps.Red reduces the SID List (i.d) carried in SRH by pushing the
> > +# first SID (fcff:1::e) in the IPv6 DA.
> > +#
> > +# In summary:
> > +#  * hs-3 -> hs-4 |IPv6 DA=fcff:2::e|SRH SIDs=fcff:4::d46|IPv6|...| (i.c)
> > +#  * hs-4 -> hs-3 |IPv6 DA=fcff:1::e|SRH SIDs=fcff:3::d46|IPv6|...| (i.d)
> > +#
> > +
> > +# Kselftest framework requirement - SKIP code is 4.
> > +ksft_skip=4
> > +
> > +readonly VRF_TID=100
> > +readonly LOCALSID_TABLE_ID=90
> > +readonly IPv6_RT_NETWORK=fcf0:0
> > +readonly IPv6_HS_NETWORK=cafe
> > +readonly IPv4_HS_NETWORK=10.0.0
> > +readonly VPN_LOCATOR_SERVICE=fcff
> > +readonly END_FUNC=000e
> > +readonly DT46_FUNC=0d46
> > +PING_TIMEOUT_SEC=4
> > +
> > +# global vars initialized during the setup of the selftest network
> > +ROUTERS=''
> > +HOSTS=''
> > +
> > +ret=0
> > +
> > +PAUSE_ON_FAIL=${PAUSE_ON_FAIL:=no}
> > +
> > +log_test()
> > +{
> > +	local rc=$1
> > +	local expected=$2
> > +	local msg="$3"
> > +
> > +	if [ ${rc} -eq ${expected} ]; then
> > +		nsuccess=$((nsuccess+1))
> > +		printf "\n    TEST: %-60s  [ OK ]\n" "${msg}"
> > +	else
> > +		ret=1
> > +		nfail=$((nfail+1))
> > +		printf "\n    TEST: %-60s  [FAIL]\n" "${msg}"
> > +		if [ "${PAUSE_ON_FAIL}" = "yes" ]; then
> > +			echo
> > +			echo "hit enter to continue, 'q' to quit"
> > +			read a
> > +			[ "$a" = "q" ] && exit 1
> > +		fi
> > +	fi
> > +}
> > +
> > +print_log_test_results()
> > +{
> > +	if [ "$TESTS" != "none" ]; then
> > +		printf "\nTests passed: %3d\n" ${nsuccess}
> > +		printf "Tests failed: %3d\n"   ${nfail}
> > +	fi
> > +}
> > +
> > +log_section()
> > +{
> > +	echo
> > +	echo "################################################################################"
> > +	echo "TEST SECTION: $*"
> > +	echo "################################################################################"
> > +}
> > +
> > +test_command_or_ksft_skip()
> > +{
> > +	local cmd="$1"
> > +
> > +	if [ ! -x "$(command -v "${cmd}")" ]; then
> > +		echo "SKIP: Could not run test without \"${cmd}\" tool";
> > +		exit ${ksft_skip}
> > +	fi
> > +}
> > +
> > +cleanup()
> > +{
> > +	local ifnames
> > +	local dev
> > +
> > +	ifnames="$(ip -o link show | grep -oE "veth-rt-[0-9]+-[0-9]" | sort -n | uniq)"
> > +
> > +	# destroy any pending device
> > +	for dev in ${ifnames}; do
> > +		ip link del ${dev} || true
> > +	done
> 
> It's better if you create/place all the virtual devices you need in
> some netns: the cleanup will be easier, and the self-test will not be
> impacted by some unexpected configuration in the main netns.
> 

Ok.

> > +
> > +	# destroy routers rt-* and hosts hs-*
> > +	for ns in $(ip netns show | grep -E 'rt-*|hs-*'); do
> 
> It's better if you add to your netns name some random suffix to avoid
> possible conflicts with unexpected system configuration. 
> 

Ok, fine.

> > +		ip netns del ${ns} || true
> > +	done
> > +}
> > +
> > +add_link_rt_pairs()
> > +{
> > +	local rt=$1
> > +	local rt_neighs="$2"
> > +	local neigh
> > +
> > +	for neigh in ${rt_neighs}; do
> > +		ip link add veth-rt-${rt}-${neigh} type veth \
> > +			peer name veth-rt-${neigh}-${rt}
> > +	done
> > +}
> > +
> > +get_network_prefix()
> > +{
> > +	local rt=$1
> > +	local neigh=$2
> > +	local p=${rt}
> > +	local q=${neigh}
> > +
> > +	if [ "${p}" -gt "${q}" ]; then
> > +		p=${q}; q=${rt};
> > +	fi
> > +
> > +	echo "${IPv6_RT_NETWORK}:${p}:${q}"
> > +}
> > +
> > +# Setup the basic networking for the routers
> > +setup_rt_networking()
> > +{
> > +	local rt=$1
> > +	local rt_neighs="$2"
> > +	local nsname=rt-${rt}
> > +	local net_prefix
> > +	local devname
> > +	local neigh
> > +
> > +	ip netns add ${nsname}
> > +
> > +	for neigh in ${rt_neighs}; do
> > +		devname=veth-rt-${rt}-${neigh}
> > +		ip link set ${devname} netns ${nsname}
> > +
> > +		net_prefix="$(get_network_prefix ${rt} ${neigh})"
> > +
> > +		ip -netns ${nsname} addr add ${net_prefix}::${rt}/64 \
> > +			dev ${devname} nodad
> > +
> > +		ip -netns ${nsname} link set ${devname} up
> > +	done
> > +
> > +	ip -netns ${nsname} link set lo up
> > +
> > +	ip netns exec ${nsname} sysctl -wq net.ipv6.conf.all.accept_dad=0
> > +	ip netns exec ${nsname} sysctl -wq net.ipv6.conf.default.accept_dad=0
> > +	ip netns exec ${nsname} sysctl -wq net.ipv6.conf.all.forwarding=1
> > +
> > +	ip netns exec ${nsname} sysctl -wq net.ipv4.conf.all.rp_filter=0
> > +	ip netns exec ${nsname} sysctl -wq net.ipv4.conf.default.rp_filter=0
> > +	ip netns exec ${nsname} sysctl -wq net.ipv4.ip_forward=1
> > +}
> > +
> > +# Setup local SIDs for an SRv6 router
> > +setup_rt_local_sids()
> > +{
> > +	local rt=$1
> > +	local rt_neighs="$2"
> > +	local nsname=rt-${rt}
> > +	local rtveth=veth-t${VRF_TID}
> > +	local net_prefix
> > +	local devname
> > +	local neigh
> > +
> > +	for neigh in ${rt_neighs}; do
> > +		devname=veth-rt-${rt}-${neigh}
> > +
> > +		net_prefix="$(get_network_prefix ${rt} ${neigh})"
> > +
> > +		# set underlay network routes for SIDs reachability
> > +		ip -netns ${nsname} -6 route add ${VPN_LOCATOR_SERVICE}:${neigh}::/32 \
> > +			table ${LOCALSID_TABLE_ID} \
> > +			via ${net_prefix}::${neigh} dev ${devname}
> > +	done
> > +
> > +	# Local End behavior (note that "dev" is dummy and the VRF is chosen
> > +	# for the sake of simplicity).
> > +	ip -netns ${nsname} -6 route add ${VPN_LOCATOR_SERVICE}:${rt}::${END_FUNC} \
> > +		table ${LOCALSID_TABLE_ID} \
> > +		encap seg6local action End count dev vrf-${VRF_TID}
> > +
> > +	# Local End.DT46 behavior
> > +	ip -netns ${nsname} -6 route add ${VPN_LOCATOR_SERVICE}:${rt}::${DT46_FUNC} \
> > +		table ${LOCALSID_TABLE_ID} \
> > +		encap seg6local action End.DT46 vrftable ${VRF_TID} count dev vrf-${VRF_TID}
> > +
> > +	# all SIDs for VPNs start with a common locator. Routes and SRv6
> > +	# Endpoint behaviors instaces are grouped together in the 'localsid'
> > +	# table.
> > +	ip -netns ${nsname} -6 rule add \
> > +			to ${VPN_LOCATOR_SERVICE}::/16 \
> > +			lookup ${LOCALSID_TABLE_ID} prio 999
> > +
> > +	# set default routes to unreachable for both ipv4 and ipv6
> > +	ip -netns ${nsname} -6 route add unreachable default metric 4278198272 \
> > +		vrf vrf-${VRF_TID}
> > +
> > +	ip -netns ${nsname} -4 route add unreachable default metric 4278198272 \
> > +		vrf vrf-${VRF_TID}
> > +}
> > +
> > +# build and install the SRv6 policy into the ingress SRv6 router.
> > +# args:
> > +#  $1 - destination host (i.e. cafe::x host)
> > +#  $2 - SRv6 router configured for enforcing the SRv6 Policy
> > +#  $3 - SRv6 routers configured for steering traffic (End behaviors)
> > +#  $4 - SRv6 router configured for removing the SRv6 Policy (router connected
> > +#       to the destination host)
> > +#  $5 - encap mode (full or red)
> > +#  $6 - traffic type (IPv6 or IPv4)
> > +__setup_rt_policy()
> > +{
> > +	local dst=$1
> > +	local encap=$2
> > +	local end_rts="$3"
> > +	local dec_rt=$4
> > +	local mode="$5"
> > +	local traffic=$6
> > +	local nsname=rt-${encap}
> > +	local rtveth=veth-t${VRF_TID}
> > +	local policy=''
> > +	local n
> > +
> > +	for n in ${end_rts}; do
> > +		policy=${policy}"${VPN_LOCATOR_SERVICE}:${n}::${END_FUNC},"
> > +	done
> > +
> > +	policy=${policy}"${VPN_LOCATOR_SERVICE}:${dec_rt}::${DT46_FUNC}"
> > +
> > +	# add SRv6 policy to incoming traffic sent by attached hosts
> > +	if [ "${traffic}" -eq 6 ]; then
> > +		ip -netns ${nsname} -6 route add ${IPv6_HS_NETWORK}::${dst} vrf vrf-${VRF_TID} \
> > +			encap seg6 mode ${mode} segs ${policy} dev vrf-${VRF_TID}
> > +
> > +		ip -netns ${nsname} -6 neigh add proxy ${IPv6_HS_NETWORK}::${dst} dev ${rtveth}
> > +	else
> > +		# "dev" must be different from the one where the packet is
> > +		# received, otherwise the proxy arp does not work.
> > +		ip -netns ${nsname} -4 route add ${IPv4_HS_NETWORK}.${dst} vrf vrf-${VRF_TID} \
> > +			encap seg6 mode ${mode} segs ${policy} dev vrf-${VRF_TID}
> > +	fi
> > +}
> > +
> > +# see __setup_rt_policy
> > +setup_rt_policy_ipv6()
> > +{
> > +	__setup_rt_policy "$1" "$2" "$3" "$4" "$5" 6
> > +}
> > +
> > +#see __setup_rt_policy
> > +setup_rt_policy_ipv4()
> > +{
> > +	__setup_rt_policy "$1" "$2" "$3" "$4" "$5" 4
> > +}
> > +
> > +setup_hs()
> > +{
> > +	local hs=$1
> > +	local rt=$2
> > +	local hsname=hs-${hs}
> > +	local rtname=rt-${rt}
> > +	local rtveth=veth-t${VRF_TID}
> > +
> > +	# set the networking for the host
> > +	ip netns add ${hsname}
> > +
> > +	ip netns exec ${hsname} sysctl -wq net.ipv6.conf.all.accept_dad=0
> > +	ip netns exec ${hsname} sysctl -wq net.ipv6.conf.default.accept_dad=0
> > +
> > +	ip -netns ${hsname} link add veth0 type veth peer name ${rtveth}
> > +	ip -netns ${hsname} link set ${rtveth} netns ${rtname}
> > +	ip -netns ${hsname} addr add ${IPv6_HS_NETWORK}::${hs}/64 dev veth0 nodad
> > +	ip -netns ${hsname} addr add ${IPv4_HS_NETWORK}.${hs}/24 dev veth0
> > +	ip -netns ${hsname} link set veth0 up
> > +	ip -netns ${hsname} link set lo up
> > +
> > +	# configure the VRF on the router which is directly connected to the
> > +	# source host.
> > +	ip -netns ${rtname} link add vrf-${VRF_TID} type vrf table ${VRF_TID}
> > +	ip -netns ${rtname} link set vrf-${VRF_TID} up
> > +
> > +	# enslave the veth-tX interface to the vrf-X in the access router
> > +	ip -netns ${rtname} link set ${rtveth} master vrf-${VRF_TID}
> > +	ip -netns ${rtname} addr add ${IPv6_HS_NETWORK}::254/64 dev ${rtveth} nodad
> > +	ip -netns ${rtname} addr add ${IPv4_HS_NETWORK}.254/24 dev ${rtveth}
> > +	ip -netns ${rtname} link set ${rtveth} up
> > +
> > +	ip netns exec ${rtname} sysctl -wq net.ipv6.conf.${rtveth}.proxy_ndp=1
> > +	ip netns exec ${rtname} sysctl -wq net.ipv4.conf.${rtveth}.proxy_arp=1
> > +
> > +	# disable the rp_filter otherwise the kernel gets confused about how
> > +	# to route decap ipv4 packets.
> > +	ip netns exec ${rtname} sysctl -wq net.ipv4.conf.${rtveth}.rp_filter=0
> > +
> > +	ip netns exec ${rtname} sh -c "echo 1 > /proc/sys/net/vrf/strict_mode"
> > +}
> > +
> > +setup()
> > +{
> > +	# set up the links for connecting routers
> > +	add_link_rt_pairs 1 "2 3 4"
> > +	add_link_rt_pairs 2 "3 4"
> > +	add_link_rt_pairs 3 "4"
> > +
> > +	# set up the basic connectivity of routers and routes required for
> > +	# reachability of SIDs.
> > +	ROUTERS="1 2 3 4"
> > +	setup_rt_networking 1 "2 3 4"
> > +	setup_rt_networking 2 "1 3 4"
> > +	setup_rt_networking 3 "1 2 4"
> > +	setup_rt_networking 4 "1 2 3"
> > +
> > +	# set up the hosts connected to routers
> > +	HOSTS="1 2 3 4"
> > +	setup_hs 1 1
> > +	setup_hs 2 2
> > +	setup_hs 3 3
> > +	setup_hs 4 4
> > +
> > +	# set up default SRv6 Endpoints (i.e. SRv6 End and SRv6 End.DT46)
> > +	setup_rt_local_sids 1 "2 3 4"
> > +	setup_rt_local_sids 2 "1 3 4"
> > +	setup_rt_local_sids 3 "1 2 4"
> > +	setup_rt_local_sids 4 "1 2 3"
> > +
> > +	# set up SRv6 policies
> > +
> > +	# create an IPv6 VPN between hosts hs-1 and hs-2.
> > +	# the network path between hs-1 and hs-2 traverses several routers
> > +	# depending on the direction of traffic.
> > +	#
> > +	# Direction hs-1 -> hs-2 (H.Encaps.Red)
> > +	#  - rt-3,rt-4 (SRv6 End behaviors)
> > +	#  - rt-2 (SRv6 End.DT46 behavior)
> > +	#
> > +	# Direction hs-2 -> hs-1 (H.Encaps.Red)
> > +	#  - rt-1 (SRv6 End.DT46 behavior)
> > +	setup_rt_policy_ipv6 2 1 "3 4" 2 encap.red
> > +	setup_rt_policy_ipv6 1 2 "" 1 encap.red
> > +
> > +	# create an IPv4 VPN between hosts hs-1 and hs-2
> > +	# the network path between hs-1 and hs-2 traverses several routers
> > +	# depending on the direction of traffic.
> > +	#
> > +	# Direction hs-1 -> hs-2 (H.Encaps.Red)
> > +	# - rt-2 (SRv6 End.DT46 behavior)
> > +	#
> > +	# Direction hs-2 -> hs-1 (H.Encaps.Red)
> > +	#  - rt-4,rt-3 (SRv6 End behaviors)
> > +	#  - rt-1 (SRv6 End.DT46 behavior)
> > +	setup_rt_policy_ipv4 2 1 "" 2 encap.red
> > +	setup_rt_policy_ipv4 1 2 "4 3" 1 encap.red
> > +
> > +	# create an IPv6 VPN between hosts hs-3 and hs-4
> > +	# the network path between hs-3 and hs-4 traverses several routers
> > +	# depending on the direction of traffic.
> > +	#
> > +	# Direction hs-3 -> hs-4 (H.Encaps.Red)
> > +	# - rt-2 (SRv6 End Behavior)
> > +	# - rt-4 (SRv6 End.DT46 behavior)
> > +	#
> > +	# Direction hs-4 -> hs-3 (H.Encaps.Red)
> > +	#  - rt-1 (SRv6 End behavior)
> > +	#  - rt-3 (SRv6 End.DT46 behavior)
> > +	setup_rt_policy_ipv6 4 3 "2" 4 encap.red
> > +	setup_rt_policy_ipv6 3 4 "1" 3 encap.red
> > +}
> > +
> > +check_rt_connectivity()
> > +{
> > +	local rtsrc=$1
> > +	local rtdst=$2
> > +	local prefix
> > +
> > +	prefix="$(get_network_prefix ${rtsrc} ${rtdst})"
> > +
> > +	ip netns exec rt-${rtsrc} ping -c 1 -W 1 ${prefix}::${rtdst} \
> > +		>/dev/null 2>&1
> > +}
> > +
> > +check_and_log_rt_connectivity()
> > +{
> > +	local rtsrc=$1
> > +	local rtdst=$2
> > +
> > +	check_rt_connectivity ${rtsrc} ${rtdst}
> > +	log_test $? 0 "Routers connectivity: rt-${rtsrc} -> rt-${rtdst}"
> > +}
> > +
> > +check_hs_ipv6_connectivity()
> > +{
> > +	local hssrc=$1
> > +	local hsdst=$2
> > +
> > +	ip netns exec hs-${hssrc} ping -c 1 -W ${PING_TIMEOUT_SEC} \
> > +		${IPv6_HS_NETWORK}::${hsdst} >/dev/null 2>&1
> > +}
> > +
> > +check_hs_ipv4_connectivity()
> > +{
> > +	local hssrc=$1
> > +	local hsdst=$2
> > +
> > +	ip netns exec hs-${hssrc} ping -c 1 -W ${PING_TIMEOUT_SEC} \
> > +		${IPv4_HS_NETWORK}.${hsdst} >/dev/null 2>&1
> > +}
> > +
> > +check_and_log_hs2gw_connectivity()
> > +{
> > +	local hssrc=$1
> > +
> > +	check_hs_ipv6_connectivity ${hssrc} 254
> > +	log_test $? 0 "IPv6 Hosts connectivity: hs-${hssrc} -> gw"
> > +
> > +	check_hs_ipv4_connectivity ${hssrc} 254
> > +	log_test $? 0 "IPv4 Hosts connectivity: hs-${hssrc} -> gw"
> > +}
> > +
> > +check_and_log_hs_ipv6_connectivity()
> > +{
> > +	local hssrc=$1
> > +	local hsdst=$2
> > +
> > +	check_hs_ipv6_connectivity ${hssrc} ${hsdst}
> > +	log_test $? 0 "IPv6 Hosts connectivity: hs-${hssrc} -> hs-${hsdst}"
> > +}
> > +
> > +check_and_log_hs_ipv4_connectivity()
> > +{
> > +	local hssrc=$1
> > +	local hsdst=$2
> > +
> > +	check_hs_ipv4_connectivity ${hssrc} ${hsdst}
> > +	log_test $? 0 "IPv4 Hosts connectivity: hs-${hssrc} -> hs-${hsdst}"
> > +}
> > +
> > +check_and_log_hs_connectivity()
> > +{
> > +	local hssrc=$1
> > +	local hsdst=$2
> > +
> > +	check_and_log_hs_ipv4_connectivity ${hssrc} ${hsdst}
> > +	check_and_log_hs_ipv6_connectivity ${hssrc} ${hsdst}
> > +}
> > +
> > +check_and_log_hs_ipv6_isolation()
> > +{
> > +	local hssrc=$1
> > +	local hsdst=$2
> > +
> > +	check_hs_ipv6_connectivity ${hssrc} ${hsdst}
> > +	log_test $? 1 "IPv6 Hosts isolation: hs-${hssrc} -X-> hs-${hsdst}"
> > +}
> > +
> > +check_and_log_hs_ipv4_isolation()
> > +{
> > +	local hssrc=$1
> > +	local hsdst=$2
> > +
> > +	check_hs_ipv4_connectivity ${hssrc} ${hsdst}
> > +	log_test $? 1 "IPv4 Hosts isolation: hs-${hssrc} -X-> hs-${hsdst}"
> > +}
> > +
> > +check_and_log_hs_isolation()
> > +{
> > +	local hssrc=$1
> > +	local hsdst=$2
> > +
> > +	check_and_log_hs_ipv6_isolation ${hssrc} ${hsdst}
> > +	check_and_log_hs_ipv4_isolation ${hssrc} ${hsdst}
> > +}
> > +
> > +router_tests()
> > +{
> > +	local i
> > +	local j
> > +
> > +	log_section "IPv6 routers connectivity test"
> > +
> > +	for i in ${ROUTERS}; do
> > +		for j in ${ROUTERS}; do
> > +			if [ ${i} -eq ${j} ]; then
> > +				continue
> > +			fi
> > +
> > +			check_and_log_rt_connectivity ${i} ${j}
> > +		done
> > +	done
> > +}
> > +
> > +host2gateway_tests()
> > +{
> > +	local hs
> > +
> > +	log_section "IPv4/IPv6 connectivity test among hosts and gateways"
> > +
> > +	for hs in ${HOSTS}; do
> > +		check_and_log_hs2gw_connectivity ${hs}
> > +	done
> > +}
> > +
> > +host_vpn_tests()
> > +{
> > +	log_section "SRv6 VPN connectivity test hosts (h1 <-> h2, IPv4/IPv6)"
> > +
> > +	check_and_log_hs_connectivity 1 2
> > +	check_and_log_hs_connectivity 2 1
> > +
> > +	log_section "SRv6 VPN connectivity test hosts (h3 <-> h4, IPv6 only)"
> > +
> > +	check_and_log_hs_ipv6_connectivity 3 4
> > +	check_and_log_hs_ipv6_connectivity 4 3
> > +}
> > +
> > +host_vpn_isolation_tests()
> > +{
> > +	local l1="1 2"
> > +	local l2="3 4"
> > +	local tmp
> > +	local i
> > +	local j
> > +	local k
> > +
> > +	log_section "SRv6 VPN isolation test among hosts"
> > +
> > +	for k in 0 1; do
> > +		for i in ${l1}; do
> > +			for j in ${l2}; do
> > +				check_and_log_hs_isolation ${i} ${j}
> > +			done
> > +		done
> > +
> > +		# let us test the reverse path
> > +		tmp="${l1}"; l1="${l2}"; l2="${tmp}"
> > +		tmp=${t1}; t1=${t2}; t2=${tmp}
> > +	done
> > +
> > +	log_section "SRv6 VPN isolation test among hosts (h2 <-> h4, IPv4 only)"
> > +
> > +	check_and_log_hs_ipv4_isolation 2 4
> > +	check_and_log_hs_ipv4_isolation 4 2
> > +}
> > +
> > +test_vrf_or_ksft_skip()
> > +{
> > +	modprobe vrf &>/dev/null
> > +	if [ ! -e /proc/sys/net/vrf/strict_mode ]; then
> > +		echo "SKIP: vrf sysctl does not exist"
> > +		exit ${ksft_skip}
> > +	fi
> > +}
> > +
> > +if [ "$(id -u)" -ne 0 ];then
> > +	echo "SKIP: Need root privileges"
> > +	exit ${ksft_skip}
> > +fi
> > +
> > +# required programs to carry out this selftest
> > +test_command_or_ksft_skip ip
> > +test_command_or_ksft_skip grep
> > +test_command_or_ksft_skip sort
> > +test_command_or_ksft_skip uniq
> > +
> > +test_vrf_or_ksft_skip
> > +
> > +cleanup &>/dev/null
> 
> If you use:
> 
> trap cleanup EXIT
> 
> you don't need this "strange" inital cleanup and the self-test will be
> more resilient WRT unexected interruptions.
> 

Ok, thanks.

Ciao,
Andrea