selftests: add selftest for the SRv6 End.DT6 (VRF) behavior

#!/bin/bash

# SPDX-License-Identifier: GPL-2.0

#

# author: Andrea Mayer <andrea.mayer@uniroma2.it>

# author: Paolo Lungaroni <paolo.lungaroni@cnit.it>

# This test is designed for evaluating the new SRv6 End.DT6 behavior used for

# implementing IPv6 L3 VPN use cases.

#

# Hereafter a network diagram is shown, where two different tenants (named 100

# and 200) offer IPv6 L3 VPN services allowing hosts to communicate with each

# other across an IPv6 network.

#

# Only hosts belonging to the same tenant (and to the same VPN) can communicate

# with each other. Instead, the communication among hosts of different tenants

# is forbidden.

# In other words, hosts hs-t100-1 and hs-t100-2 are connected through the IPv6

# L3 VPN of tenant 100 while hs-t200-3 and hs-t200-4 are connected using the

# IPv6 L3 VPN of tenant 200. Cross connection between tenant 100 and tenant 200

# is forbidden and thus, for example, hs-t100-1 cannot reach hs-t200-3 and vice

# versa.

#

# Routers rt-1 and rt-2 implement IPv6 L3 VPN services leveraging the SRv6

# architecture. The key components for such VPNs are: a) SRv6 Encap behavior,

# b) SRv6 End.DT6 behavior and c) VRF.

#

# To explain how an IPv6 L3 VPN based on SRv6 works, let us briefly consider an

# example where, within the same domain of tenant 100, the host hs-t100-1 pings

# the host hs-t100-2.

#

# First of all, L2 reachability of the host hs-t100-2 is taken into account by

# the router rt-1 which acts as a ndp proxy.

#

# When the host hs-t100-1 sends an IPv6 packet destined to hs-t100-2, the

# router rt-1 receives the packet on the internal veth-t100 interface. Such

# interface is enslaved to the VRF vrf-100 whose associated table contains the

# SRv6 Encap route for encapsulating any IPv6 packet in a IPv6 plus the Segment

# Routing Header (SRH) packet. This packet is sent through the (IPv6) core

# network up to the router rt-2 that receives it on veth0 interface.

#

# The rt-2 router uses the 'localsid' routing table to process incoming

# IPv6+SRH packets which belong to the VPN of the tenant 100. For each of these

# packets, the SRv6 End.DT6 behavior removes the outer IPv6+SRH headers and

# performs the lookup on the vrf-100 table using the destination address of

# the decapsulated IPv6 packet. Afterwards, the packet is sent to the host

# hs-t100-2 through the veth-t100 interface.

#

# The ping response follows the same processing but this time the role of rt-1

# and rt-2 are swapped.

#

# Of course, the IPv6 L3 VPN for tenant 200 works exactly as the IPv6 L3 VPN

# for tenant 100. In this case, only hosts hs-t200-3 and hs-t200-4 are able to

# connect with each other.

#

#

# +-------------------+                                   +-------------------+

# |                   |                                   |                   |

# |  hs-t100-1 netns  |                                   |  hs-t100-2 netns  |

# |                   |                                   |                   |

# |  +-------------+  |                                   |  +-------------+  |

# |  |    veth0    |  |                                   |  |    veth0    |  |

# |  |  cafe::1/64 |  |                                   |  |  cafe::2/64 |  |

# |  +-------------+  |                                   |  +-------------+  |

# |        .          |                                   |         .         |

# +-------------------+                                   +-------------------+

#          .                                                        .

#          .                                                        .

#          .                                                        .

# +-----------------------------------+   +-----------------------------------+

# |        .                          |   |                         .         |

# | +---------------+                 |   |                 +---------------- |

# | |   veth-t100   |                 |   |                 |   veth-t100   | |

# | |  cafe::254/64 |    +----------+ |   | +----------+    |  cafe::254/64 | |

# | +-------+-------+    | localsid | |   | | localsid |    +-------+-------- |

# |         |            |   table  | |   | |   table  |            |         |

# |    +----+----+       +----------+ |   | +----------+       +----+----+    |

# |    | vrf-100 |                    |   |                    | vrf-100 |    |

# |    +---------+     +------------+ |   | +------------+     +---------+    |

# |                    |   veth0    | |   | |   veth0    |                    |

# |                    | fd00::1/64 |.|...|.| fd00::2/64 |                    |

# |    +---------+     +------------+ |   | +------------+     +---------+    |

# |    | vrf-200 |                    |   |                    | vrf-200 |    |

# |    +----+----+                    |   |                    +----+----+    |

# |         |                         |   |                         |         |

# | +-------+-------+                 |   |                 +-------+-------- |

# | |   veth-t200   |                 |   |                 |   veth-t200   | |

# | |  cafe::254/64 |                 |   |                 |  cafe::254/64 | |

# | +---------------+      rt-1 netns |   | rt-2 netns      +---------------- |

# |        .                          |   |                          .        |

# +-----------------------------------+   +-----------------------------------+

#          .                                                         .

#          .                                                         .

#          .                                                         .

#          .                                                         .

# +-------------------+                                   +-------------------+

# |        .          |                                   |          .        |

# |  +-------------+  |                                   |  +-------------+  |

# |  |    veth0    |  |                                   |  |    veth0    |  |

# |  |  cafe::3/64 |  |                                   |  |  cafe::4/64 |  |

# |  +-------------+  |                                   |  +-------------+  |

# |                   |                                   |                   |

# |  hs-t200-3 netns  |                                   |  hs-t200-4 netns  |

# |                   |                                   |                   |

# +-------------------+                                   +-------------------+

#

#

# ~~~~~~~~~~~~~~~~~~~~~~~~~

# | Network configuration |

# ~~~~~~~~~~~~~~~~~~~~~~~~~

#

# rt-1: localsid table (table 90)

# +-------------------------------------------------+

# |SID              |Action                         |

# +-------------------------------------------------+

# |fc00:21:100::6006|apply SRv6 End.DT6 vrftable 100|

# +-------------------------------------------------+

# |fc00:21:200::6006|apply SRv6 End.DT6 vrftable 200|

# +-------------------------------------------------+

#

# rt-1: VRF tenant 100 (table 100)

# +---------------------------------------------------+

# |host       |Action                                 |

# +---------------------------------------------------+

# |cafe::2    |apply seg6 encap segs fc00:12:100::6006|

# +---------------------------------------------------+

# |cafe::/64  |forward to dev veth_t100               |

# +---------------------------------------------------+

#

# rt-1: VRF tenant 200 (table 200)

# +---------------------------------------------------+

# |host       |Action                                 |

# +---------------------------------------------------+

# |cafe::4    |apply seg6 encap segs fc00:12:200::6006|

# +---------------------------------------------------+

# |cafe::/64  |forward to dev veth_t200               |

# +---------------------------------------------------+

#

#

# rt-2: localsid table (table 90)

# +-------------------------------------------------+

# |SID              |Action                         |

# +-------------------------------------------------+

# |fc00:12:100::6006|apply SRv6 End.DT6 vrftable 100|

# +-------------------------------------------------+

# |fc00:12:200::6006|apply SRv6 End.DT6 vrftable 200|

# +-------------------------------------------------+

#

# rt-2: VRF tenant 100 (table 100)

# +---------------------------------------------------+

# |host       |Action                                 |

# +---------------------------------------------------+

# |cafe::1    |apply seg6 encap segs fc00:21:100::6006|

# +---------------------------------------------------+

# |cafe::/64  |forward to dev veth_t100               |

# +---------------------------------------------------+

#

# rt-2: VRF tenant 200 (table 200)

# +---------------------------------------------------+

# |host       |Action                                 |

# +---------------------------------------------------+

# |cafe::3    |apply seg6 encap segs fc00:21:200::6006|

# +---------------------------------------------------+

# |cafe::/64  |forward to dev veth_t200               |

# +---------------------------------------------------+

#

readonly LOCALSID_TABLE_ID=90

readonly IPv6_RT_NETWORK=fd00

readonly IPv6_HS_NETWORK=cafe

readonly VPN_LOCATOR_SERVICE=fc00

PING_TIMEOUT_SEC=4

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 "################################################################################"

}

cleanup()

{

	ip link del veth-rt-1 2>/dev/null || true

	ip link del veth-rt-2 2>/dev/null || true

	# destroy routers rt-* and hosts hs-*

	for ns in $(ip netns show | grep -E 'rt-*|hs-*'); do

		ip netns del ${ns} || true

	done

}

# Setup the basic networking for the routers

setup_rt_networking()

{

	local rt=$1

	local nsname=rt-${rt}

	ip netns add ${nsname}

	ip link set veth-rt-${rt} netns ${nsname}

	ip -netns ${nsname} link set veth-rt-${rt} name veth0

	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 ${nsname} addr add ${IPv6_RT_NETWORK}::${rt}/64 dev veth0 nodad

	ip -netns ${nsname} link set veth0 up

	ip -netns ${nsname} link set lo up

	ip netns exec ${nsname} sysctl -wq net.ipv6.conf.all.forwarding=1

}

setup_hs()

{

	local hs=$1

	local rt=$2

	local tid=$3

	local hsname=hs-t${tid}-${hs}

	local rtname=rt-${rt}

	local rtveth=veth-t${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} link set veth0 up

	ip -netns ${hsname} link set lo up

	# configure the VRF for the tenant X on the router which is directly

	# connected to the source host.

	ip -netns ${rtname} link add vrf-${tid} type vrf table ${tid}

	ip -netns ${rtname} link set vrf-${tid} up

	ip netns exec ${rtname} sysctl -wq net.ipv6.conf.all.accept_dad=0

	ip netns exec ${rtname} sysctl -wq net.ipv6.conf.default.accept_dad=0

	# enslave the veth-tX interface to the vrf-X in the access router

	ip -netns ${rtname} link set ${rtveth} master vrf-${tid}

	ip -netns ${rtname} addr add ${IPv6_HS_NETWORK}::254/64 dev ${rtveth} nodad

	ip -netns ${rtname} link set ${rtveth} up

	ip netns exec ${rtname} sysctl -wq net.ipv6.conf.${rtveth}.proxy_ndp=1

	ip netns exec ${rtname} sh -c "echo 1 > /proc/sys/net/vrf/strict_mode"

}

setup_vpn_config()

{

	local hssrc=$1

	local rtsrc=$2

	local hsdst=$3

	local rtdst=$4

	local tid=$5

	local hssrc_name=hs-t${tid}-${hssrc}

	local hsdst_name=hs-t${tid}-${hsdst}

	local rtsrc_name=rt-${rtsrc}

	local rtdst_name=rt-${rtdst}

	local rtveth=veth-t${tid}

	local vpn_sid=${VPN_LOCATOR_SERVICE}:${hssrc}${hsdst}:${tid}::6006

	ip -netns ${rtsrc_name} -6 neigh add proxy ${IPv6_HS_NETWORK}::${hsdst} dev ${rtveth}

	# set the encap route for encapsulating packets which arrive from the

	# host hssrc and destined to the access router rtsrc.

	ip -netns ${rtsrc_name} -6 route add ${IPv6_HS_NETWORK}::${hsdst}/128 vrf vrf-${tid} \

		encap seg6 mode encap segs ${vpn_sid} dev veth0

	ip -netns ${rtsrc_name} -6 route add ${vpn_sid}/128 vrf vrf-${tid} \

		via fd00::${rtdst} dev veth0

	# set the decap route for decapsulating packets which arrive from

	# the rtdst router and destined to the hsdst host.

	ip -netns ${rtdst_name} -6 route add ${vpn_sid}/128 table ${LOCALSID_TABLE_ID} \

		encap seg6local action End.DT6 vrftable ${tid} dev vrf-${tid}

	# all sids for VPNs start with a common locator which is fc00::/16.

	# Routes for handling the SRv6 End.DT6 behavior instances are grouped

	# together in the 'localsid' table.

	#

	# NOTE: added only once

	if [ -z "$(ip -netns ${rtdst_name} -6 rule show | \

	    grep "to ${VPN_LOCATOR_SERVICE}::/16 lookup ${LOCALSID_TABLE_ID}")" ]; then

		ip -netns ${rtdst_name} -6 rule add \

			to ${VPN_LOCATOR_SERVICE}::/16 \

			lookup ${LOCALSID_TABLE_ID} prio 999

	fi

}

setup()

{

	ip link add veth-rt-1 type veth peer name veth-rt-2

	# setup the networking for router rt-1 and router rt-2

	setup_rt_networking 1

	setup_rt_networking 2

	# setup two hosts for the tenant 100.

	#  - host hs-1 is directly connected to the router rt-1;

	#  - host hs-2 is directly connected to the router rt-2.

	setup_hs 1 1 100  #args: host router tenant

	setup_hs 2 2 100

	# setup two hosts for the tenant 200

	#  - host hs-3 is directly connected to the router rt-1;

	#  - host hs-4 is directly connected to the router rt-2.

	setup_hs 3 1 200

	setup_hs 4 2 200

	# setup the IPv6 L3 VPN which connects the host hs-t100-1 and host

	# hs-t100-2 within the same tenant 100.

	setup_vpn_config 1 1 2 2 100  #args: src_host src_router dst_host dst_router tenant

	setup_vpn_config 2 2 1 1 100

	# setup the IPv6 L3 VPN which connects the host hs-t200-3 and host

	# hs-t200-4 within the same tenant 200.

	setup_vpn_config 3 1 4 2 200

	setup_vpn_config 4 2 3 1 200

}

check_rt_connectivity()

{

	local rtsrc=$1

	local rtdst=$2

	ip netns exec rt-${rtsrc} ping -c 1 -W 1 ${IPv6_RT_NETWORK}::${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_connectivity()

{

	local hssrc=$1

	local hsdst=$2

	local tid=$3

	ip netns exec hs-t${tid}-${hssrc} ping -c 1 -W ${PING_TIMEOUT_SEC} \

		${IPv6_HS_NETWORK}::${hsdst} >/dev/null 2>&1

}

check_and_log_hs_connectivity()

{

	local hssrc=$1

	local hsdst=$2

	local tid=$3

	check_hs_connectivity ${hssrc} ${hsdst} ${tid}

	log_test $? 0 "Hosts connectivity: hs-t${tid}-${hssrc} -> hs-t${tid}-${hsdst} (tenant ${tid})"

}

check_and_log_hs_isolation()

{

	local hssrc=$1

	local tidsrc=$2

	local hsdst=$3

	local tiddst=$4

	check_hs_connectivity ${hssrc} ${hsdst} ${tidsrc}

	# NOTE: ping should fail

	log_test $? 1 "Hosts isolation: hs-t${tidsrc}-${hssrc} -X-> hs-t${tiddst}-${hsdst}"

}

check_and_log_hs2gw_connectivity()

{

	local hssrc=$1

	local tid=$2

	check_hs_connectivity ${hssrc} 254 ${tid}

	log_test $? 0 "Hosts connectivity: hs-t${tid}-${hssrc} -> gw (tenant ${tid})"

}

router_tests()

{

	log_section "IPv6 routers connectivity test"

	check_and_log_rt_connectivity 1 2

	check_and_log_rt_connectivity 2 1

}

host2gateway_tests()

{

	log_section "IPv6 connectivity test among hosts and gateway"

	check_and_log_hs2gw_connectivity 1 100

	check_and_log_hs2gw_connectivity 2 100

	check_and_log_hs2gw_connectivity 3 200

	check_and_log_hs2gw_connectivity 4 200

}

host_vpn_tests()

{

	log_section "SRv6 VPN connectivity test among hosts in the same tenant"

	check_and_log_hs_connectivity 1 2 100

	check_and_log_hs_connectivity 2 1 100

	check_and_log_hs_connectivity 3 4 200

	check_and_log_hs_connectivity 4 3 200

}

host_vpn_isolation_tests()

{

	local i

	local j

	local k

	local tmp

	local l1="1 2"

	local l2="3 4"

	local t1=100

	local t2=200

	log_section "SRv6 VPN isolation test among hosts in different tentants"

	for k in 0 1; do

		for i in ${l1}; do

			for j in ${l2}; do

				check_and_log_hs_isolation ${i} ${t1} ${j} ${t2}

			done

		done

		# let us test the reverse path

		tmp="${l1}"; l1="${l2}"; l2="${tmp}"

		tmp=${t1}; t1=${t2}; t2=${tmp}

	done

}

if [ "$(id -u)" -ne 0 ];then

	echo "SKIP: Need root privileges"

	exit 0

fi

if [ ! -x "$(command -v ip)" ]; then

	echo "SKIP: Could not run test without ip tool"

	exit 0

fi

modprobe vrf &>/dev/null

if [ ! -e /proc/sys/net/vrf/strict_mode ]; then

        echo "SKIP: vrf sysctl does not exist"

        exit 0

fi

cleanup &>/dev/null

setup

router_tests

host2gateway_tests

host_vpn_tests

host_vpn_isolation_tests

print_log_test_results

cleanup &>/dev/null

exit ${ret}