1#!/bin/bash
2# SPDX-License-Identifier: GPL-2.0
3#
4# author: Andrea Mayer <andrea.mayer@uniroma2.it>
5# author: Paolo Lungaroni <paolo.lungaroni@uniroma2.it>
6
7# This test is designed for evaluating the new SRv6 End.DT46 Behavior used for
8# implementing IPv4/IPv6 L3 VPN use cases.
9#
10# The current SRv6 code in the Linux kernel only implements SRv6 End.DT4 and
11# End.DT6 Behaviors which can be used respectively to support IPv4-in-IPv6 and
12# IPv6-in-IPv6 VPNs. With End.DT4 and End.DT6 it is not possible to create a
13# single SRv6 VPN tunnel to carry both IPv4 and IPv6 traffic.
14# The SRv6 End.DT46 Behavior implementation is meant to support the
15# decapsulation of IPv4 and IPv6 traffic coming from a single SRv6 tunnel.
16# Therefore, the SRv6 End.DT46 Behavior in the Linux kernel greatly simplifies
17# the setup and operations of SRv6 VPNs.
18#
19# Hereafter a network diagram is shown, where two different tenants (named 100
20# and 200) offer IPv4/IPv6 L3 VPN services allowing hosts to communicate with
21# each other across an IPv6 network.
22#
23# Only hosts belonging to the same tenant (and to the same VPN) can communicate
24# with each other. Instead, the communication among hosts of different tenants
25# is forbidden.
26# In other words, hosts hs-t100-1 and hs-t100-2 are connected through the
27# IPv4/IPv6 L3 VPN of tenant 100 while hs-t200-3 and hs-t200-4 are connected
28# using the IPv4/IPv6 L3 VPN of tenant 200. Cross connection between tenant 100
29# and tenant 200 is forbidden and thus, for example, hs-t100-1 cannot reach
30# hs-t200-3 and vice versa.
31#
32# Routers rt-1 and rt-2 implement IPv4/IPv6 L3 VPN services leveraging the SRv6
33# architecture. The key components for such VPNs are: a) SRv6 Encap behavior,
34# b) SRv6 End.DT46 Behavior and c) VRF.
35#
36# To explain how an IPv4/IPv6 L3 VPN based on SRv6 works, let us briefly
37# consider an example where, within the same domain of tenant 100, the host
38# hs-t100-1 pings the host hs-t100-2.
39#
40# First of all, L2 reachability of the host hs-t100-2 is taken into account by
41# the router rt-1 which acts as a arp/ndp proxy.
42#
43# When the host hs-t100-1 sends an IPv6 or IPv4 packet destined to hs-t100-2,
44# the router rt-1 receives the packet on the internal veth-t100 interface. Such
45# interface is enslaved to the VRF vrf-100 whose associated table contains the
46# SRv6 Encap route for encapsulating any IPv6 or IPv4 packet in a IPv6 plus the
47# Segment Routing Header (SRH) packet. This packet is sent through the (IPv6)
48# core network up to the router rt-2 that receives it on veth0 interface.
49#
50# The rt-2 router uses the 'localsid' routing table to process incoming
51# IPv6+SRH packets which belong to the VPN of the tenant 100. For each of these
52# packets, the SRv6 End.DT46 Behavior removes the outer IPv6+SRH headers and
53# performs the lookup on the vrf-100 table using the destination address of
54# the decapsulated IPv6 or IPv4 packet. Afterwards, the packet is sent to the
55# host hs-t100-2 through the veth-t100 interface.
56#
57# The ping response follows the same processing but this time the roles of rt-1
58# and rt-2 are swapped.
59#
60# Of course, the IPv4/IPv6 L3 VPN for tenant 200 works exactly as the IPv4/IPv6
61# L3 VPN for tenant 100. In this case, only hosts hs-t200-3 and hs-t200-4 are
62# able to connect with each other.
63#
64#
65# +-------------------+                                   +-------------------+
66# |                   |                                   |                   |
67# |  hs-t100-1 netns  |                                   |  hs-t100-2 netns  |
68# |                   |                                   |                   |
69# |  +-------------+  |                                   |  +-------------+  |
70# |  |    veth0    |  |                                   |  |    veth0    |  |
71# |  |  cafe::1/64 |  |                                   |  |  cafe::2/64 |  |
72# |  | 10.0.0.1/24 |  |                                   |  | 10.0.0.2/24 |  |
73# |  +-------------+  |                                   |  +-------------+  |
74# |        .          |                                   |         .         |
75# +-------------------+                                   +-------------------+
76#          .                                                        .
77#          .                                                        .
78#          .                                                        .
79# +-----------------------------------+   +-----------------------------------+
80# |        .                          |   |                         .         |
81# | +---------------+                 |   |                 +---------------- |
82# | |   veth-t100   |                 |   |                 |   veth-t100   | |
83# | |  cafe::254/64 |                 |   |                 |  cafe::254/64 | |
84# | | 10.0.0.254/24 |    +----------+ |   | +----------+    | 10.0.0.254/24 | |
85# | +-------+-------+    | localsid | |   | | localsid |    +-------+-------- |
86# |         |            |   table  | |   | |   table  |            |         |
87# |    +----+----+       +----------+ |   | +----------+       +----+----+    |
88# |    | vrf-100 |                    |   |                    | vrf-100 |    |
89# |    +---------+     +------------+ |   | +------------+     +---------+    |
90# |                    |   veth0    | |   | |   veth0    |                    |
91# |                    | fd00::1/64 |.|...|.| fd00::2/64 |                    |
92# |    +---------+     +------------+ |   | +------------+     +---------+    |
93# |    | vrf-200 |                    |   |                    | vrf-200 |    |
94# |    +----+----+                    |   |                    +----+----+    |
95# |         |                         |   |                         |         |
96# | +-------+-------+                 |   |                 +-------+-------- |
97# | |   veth-t200   |                 |   |                 |   veth-t200   | |
98# | |  cafe::254/64 |                 |   |                 |  cafe::254/64 | |
99# | | 10.0.0.254/24 |                 |   |                 | 10.0.0.254/24 | |
100# | +---------------+      rt-1 netns |   | rt-2 netns      +---------------- |
101# |        .                          |   |                          .        |
102# +-----------------------------------+   +-----------------------------------+
103#          .                                                         .
104#          .                                                         .
105#          .                                                         .
106#          .                                                         .
107# +-------------------+                                   +-------------------+
108# |        .          |                                   |          .        |
109# |  +-------------+  |                                   |  +-------------+  |
110# |  |    veth0    |  |                                   |  |    veth0    |  |
111# |  |  cafe::3/64 |  |                                   |  |  cafe::4/64 |  |
112# |  | 10.0.0.3/24 |  |                                   |  | 10.0.0.4/24 |  |
113# |  +-------------+  |                                   |  +-------------+  |
114# |                   |                                   |                   |
115# |  hs-t200-3 netns  |                                   |  hs-t200-4 netns  |
116# |                   |                                   |                   |
117# +-------------------+                                   +-------------------+
118#
119#
120# ~~~~~~~~~~~~~~~~~~~~~~~~~
121# | Network configuration |
122# ~~~~~~~~~~~~~~~~~~~~~~~~~
123#
124# rt-1: localsid table (table 90)
125# +--------------------------------------------------+
126# |SID              |Action                          |
127# +--------------------------------------------------+
128# |fc00:21:100::6046|apply SRv6 End.DT46 vrftable 100|
129# +--------------------------------------------------+
130# |fc00:21:200::6046|apply SRv6 End.DT46 vrftable 200|
131# +--------------------------------------------------+
132#
133# rt-1: VRF tenant 100 (table 100)
134# +---------------------------------------------------+
135# |host       |Action                                 |
136# +---------------------------------------------------+
137# |cafe::2    |apply seg6 encap segs fc00:12:100::6046|
138# +---------------------------------------------------+
139# |cafe::/64  |forward to dev veth-t100               |
140# +---------------------------------------------------+
141# |10.0.0.2   |apply seg6 encap segs fc00:12:100::6046|
142# +---------------------------------------------------+
143# |10.0.0.0/24|forward to dev veth-t100               |
144# +---------------------------------------------------+
145#
146# rt-1: VRF tenant 200 (table 200)
147# +---------------------------------------------------+
148# |host       |Action                                 |
149# +---------------------------------------------------+
150# |cafe::4    |apply seg6 encap segs fc00:12:200::6046|
151# +---------------------------------------------------+
152# |cafe::/64  |forward to dev veth-t200               |
153# +---------------------------------------------------+
154# |10.0.0.4   |apply seg6 encap segs fc00:12:200::6046|
155# +---------------------------------------------------+
156# |10.0.0.0/24|forward to dev veth-t200               |
157# +---------------------------------------------------+
158#
159#
160# rt-2: localsid table (table 90)
161# +--------------------------------------------------+
162# |SID              |Action                          |
163# +--------------------------------------------------+
164# |fc00:12:100::6046|apply SRv6 End.DT46 vrftable 100|
165# +--------------------------------------------------+
166# |fc00:12:200::6046|apply SRv6 End.DT46 vrftable 200|
167# +--------------------------------------------------+
168#
169# rt-2: VRF tenant 100 (table 100)
170# +---------------------------------------------------+
171# |host       |Action                                 |
172# +---------------------------------------------------+
173# |cafe::1    |apply seg6 encap segs fc00:21:100::6046|
174# +---------------------------------------------------+
175# |cafe::/64  |forward to dev veth-t100               |
176# +---------------------------------------------------+
177# |10.0.0.1   |apply seg6 encap segs fc00:21:100::6046|
178# +---------------------------------------------------+
179# |10.0.0.0/24|forward to dev veth-t100               |
180# +---------------------------------------------------+
181#
182# rt-2: VRF tenant 200 (table 200)
183# +---------------------------------------------------+
184# |host       |Action                                 |
185# +---------------------------------------------------+
186# |cafe::3    |apply seg6 encap segs fc00:21:200::6046|
187# +---------------------------------------------------+
188# |cafe::/64  |forward to dev veth-t200               |
189# +---------------------------------------------------+
190# |10.0.0.3   |apply seg6 encap segs fc00:21:200::6046|
191# +---------------------------------------------------+
192# |10.0.0.0/24|forward to dev veth-t200               |
193# +---------------------------------------------------+
194#
195
196readonly LOCALSID_TABLE_ID=90
197readonly IPv6_RT_NETWORK=fd00
198readonly IPv6_HS_NETWORK=cafe
199readonly IPv4_HS_NETWORK=10.0.0
200readonly VPN_LOCATOR_SERVICE=fc00
201PING_TIMEOUT_SEC=4
202
203ret=0
204
205PAUSE_ON_FAIL=${PAUSE_ON_FAIL:=no}
206
207log_test()
208{
209	local rc=$1
210	local expected=$2
211	local msg="$3"
212
213	if [ ${rc} -eq ${expected} ]; then
214		nsuccess=$((nsuccess+1))
215		printf "\n    TEST: %-60s  [ OK ]\n" "${msg}"
216	else
217		ret=1
218		nfail=$((nfail+1))
219		printf "\n    TEST: %-60s  [FAIL]\n" "${msg}"
220		if [ "${PAUSE_ON_FAIL}" = "yes" ]; then
221			echo
222			echo "hit enter to continue, 'q' to quit"
223			read a
224			[ "$a" = "q" ] && exit 1
225		fi
226	fi
227}
228
229print_log_test_results()
230{
231	if [ "$TESTS" != "none" ]; then
232		printf "\nTests passed: %3d\n" ${nsuccess}
233		printf "Tests failed: %3d\n"   ${nfail}
234	fi
235}
236
237log_section()
238{
239	echo
240	echo "################################################################################"
241	echo "TEST SECTION: $*"
242	echo "################################################################################"
243}
244
245cleanup()
246{
247	ip link del veth-rt-1 2>/dev/null || true
248	ip link del veth-rt-2 2>/dev/null || true
249
250	# destroy routers rt-* and hosts hs-*
251	for ns in $(ip netns show | grep -E 'rt-*|hs-*'); do
252		ip netns del ${ns} || true
253	done
254}
255
256# Setup the basic networking for the routers
257setup_rt_networking()
258{
259	local rt=$1
260	local nsname=rt-${rt}
261
262	ip netns add ${nsname}
263	ip link set veth-rt-${rt} netns ${nsname}
264	ip -netns ${nsname} link set veth-rt-${rt} name veth0
265
266	ip netns exec ${nsname} sysctl -wq net.ipv6.conf.all.accept_dad=0
267	ip netns exec ${nsname} sysctl -wq net.ipv6.conf.default.accept_dad=0
268
269	ip -netns ${nsname} addr add ${IPv6_RT_NETWORK}::${rt}/64 dev veth0 nodad
270	ip -netns ${nsname} link set veth0 up
271	ip -netns ${nsname} link set lo up
272
273	ip netns exec ${nsname} sysctl -wq net.ipv4.ip_forward=1
274	ip netns exec ${nsname} sysctl -wq net.ipv6.conf.all.forwarding=1
275}
276
277setup_hs()
278{
279	local hs=$1
280	local rt=$2
281	local tid=$3
282	local hsname=hs-t${tid}-${hs}
283	local rtname=rt-${rt}
284	local rtveth=veth-t${tid}
285
286	# set the networking for the host
287	ip netns add ${hsname}
288
289	ip netns exec ${hsname} sysctl -wq net.ipv6.conf.all.accept_dad=0
290	ip netns exec ${hsname} sysctl -wq net.ipv6.conf.default.accept_dad=0
291
292	ip -netns ${hsname} link add veth0 type veth peer name ${rtveth}
293	ip -netns ${hsname} link set ${rtveth} netns ${rtname}
294	ip -netns ${hsname} addr add ${IPv6_HS_NETWORK}::${hs}/64 dev veth0 nodad
295	ip -netns ${hsname} addr add ${IPv4_HS_NETWORK}.${hs}/24 dev veth0
296	ip -netns ${hsname} link set veth0 up
297	ip -netns ${hsname} link set lo up
298
299	# configure the VRF for the tenant X on the router which is directly
300	# connected to the source host.
301	ip -netns ${rtname} link add vrf-${tid} type vrf table ${tid}
302	ip -netns ${rtname} link set vrf-${tid} up
303
304	ip netns exec ${rtname} sysctl -wq net.ipv6.conf.all.accept_dad=0
305	ip netns exec ${rtname} sysctl -wq net.ipv6.conf.default.accept_dad=0
306
307	# enslave the veth-tX interface to the vrf-X in the access router
308	ip -netns ${rtname} link set ${rtveth} master vrf-${tid}
309	ip -netns ${rtname} addr add ${IPv6_HS_NETWORK}::254/64 dev ${rtveth} nodad
310	ip -netns ${rtname} addr add ${IPv4_HS_NETWORK}.254/24 dev ${rtveth}
311	ip -netns ${rtname} link set ${rtveth} up
312
313	ip netns exec ${rtname} sysctl -wq net.ipv6.conf.${rtveth}.proxy_ndp=1
314	ip netns exec ${rtname} sysctl -wq net.ipv4.conf.${rtveth}.proxy_arp=1
315
316	# disable the rp_filter otherwise the kernel gets confused about how
317	# to route decap ipv4 packets.
318	ip netns exec ${rtname} sysctl -wq net.ipv4.conf.all.rp_filter=0
319	ip netns exec ${rtname} sysctl -wq net.ipv4.conf.${rtveth}.rp_filter=0
320
321	ip netns exec ${rtname} sh -c "echo 1 > /proc/sys/net/vrf/strict_mode"
322}
323
324setup_vpn_config()
325{
326	local hssrc=$1
327	local rtsrc=$2
328	local hsdst=$3
329	local rtdst=$4
330	local tid=$5
331
332	local hssrc_name=hs-t${tid}-${hssrc}
333	local hsdst_name=hs-t${tid}-${hsdst}
334	local rtsrc_name=rt-${rtsrc}
335	local rtdst_name=rt-${rtdst}
336	local rtveth=veth-t${tid}
337	local vpn_sid=${VPN_LOCATOR_SERVICE}:${hssrc}${hsdst}:${tid}::6046
338
339	ip -netns ${rtsrc_name} -6 neigh add proxy ${IPv6_HS_NETWORK}::${hsdst} dev ${rtveth}
340
341	# set the encap route for encapsulating packets which arrive from the
342	# host hssrc and destined to the access router rtsrc.
343	ip -netns ${rtsrc_name} -6 route add ${IPv6_HS_NETWORK}::${hsdst}/128 vrf vrf-${tid} \
344		encap seg6 mode encap segs ${vpn_sid} dev veth0
345	ip -netns ${rtsrc_name} -4 route add ${IPv4_HS_NETWORK}.${hsdst}/32 vrf vrf-${tid} \
346		encap seg6 mode encap segs ${vpn_sid} dev veth0
347	ip -netns ${rtsrc_name} -6 route add ${vpn_sid}/128 vrf vrf-${tid} \
348		via fd00::${rtdst} dev veth0
349
350	# set the decap route for decapsulating packets which arrive from
351	# the rtdst router and destined to the hsdst host.
352	ip -netns ${rtdst_name} -6 route add ${vpn_sid}/128 table ${LOCALSID_TABLE_ID} \
353		encap seg6local action End.DT46 vrftable ${tid} dev vrf-${tid}
354
355	# all sids for VPNs start with a common locator which is fc00::/16.
356	# Routes for handling the SRv6 End.DT46 behavior instances are grouped
357	# together in the 'localsid' table.
358	#
359	# NOTE: added only once
360	if [ -z "$(ip -netns ${rtdst_name} -6 rule show | \
361	    grep "to ${VPN_LOCATOR_SERVICE}::/16 lookup ${LOCALSID_TABLE_ID}")" ]; then
362		ip -netns ${rtdst_name} -6 rule add \
363			to ${VPN_LOCATOR_SERVICE}::/16 \
364			lookup ${LOCALSID_TABLE_ID} prio 999
365	fi
366
367	# set default routes to unreachable for both ipv4 and ipv6
368	ip -netns ${rtsrc_name} -6 route add unreachable default metric 4278198272 \
369		vrf vrf-${tid}
370
371	ip -netns ${rtsrc_name} -4 route add unreachable default metric 4278198272 \
372		vrf vrf-${tid}
373}
374
375setup()
376{
377	ip link add veth-rt-1 type veth peer name veth-rt-2
378	# setup the networking for router rt-1 and router rt-2
379	setup_rt_networking 1
380	setup_rt_networking 2
381
382	# setup two hosts for the tenant 100.
383	#  - host hs-1 is directly connected to the router rt-1;
384	#  - host hs-2 is directly connected to the router rt-2.
385	setup_hs 1 1 100  #args: host router tenant
386	setup_hs 2 2 100
387
388	# setup two hosts for the tenant 200
389	#  - host hs-3 is directly connected to the router rt-1;
390	#  - host hs-4 is directly connected to the router rt-2.
391	setup_hs 3 1 200
392	setup_hs 4 2 200
393
394	# setup the IPv4/IPv6 L3 VPN which connects the host hs-t100-1 and host
395	# hs-t100-2 within the same tenant 100.
396	setup_vpn_config 1 1 2 2 100  #args: src_host src_router dst_host dst_router tenant
397	setup_vpn_config 2 2 1 1 100
398
399	# setup the IPv4/IPv6 L3 VPN which connects the host hs-t200-3 and host
400	# hs-t200-4 within the same tenant 200.
401	setup_vpn_config 3 1 4 2 200
402	setup_vpn_config 4 2 3 1 200
403}
404
405check_rt_connectivity()
406{
407	local rtsrc=$1
408	local rtdst=$2
409
410	ip netns exec rt-${rtsrc} ping -c 1 -W 1 ${IPv6_RT_NETWORK}::${rtdst} \
411		>/dev/null 2>&1
412}
413
414check_and_log_rt_connectivity()
415{
416	local rtsrc=$1
417	local rtdst=$2
418
419	check_rt_connectivity ${rtsrc} ${rtdst}
420	log_test $? 0 "Routers connectivity: rt-${rtsrc} -> rt-${rtdst}"
421}
422
423check_hs_ipv6_connectivity()
424{
425	local hssrc=$1
426	local hsdst=$2
427	local tid=$3
428
429	ip netns exec hs-t${tid}-${hssrc} ping -c 1 -W ${PING_TIMEOUT_SEC} \
430		${IPv6_HS_NETWORK}::${hsdst} >/dev/null 2>&1
431}
432
433check_hs_ipv4_connectivity()
434{
435	local hssrc=$1
436	local hsdst=$2
437	local tid=$3
438
439	ip netns exec hs-t${tid}-${hssrc} ping -c 1 -W ${PING_TIMEOUT_SEC} \
440		${IPv4_HS_NETWORK}.${hsdst} >/dev/null 2>&1
441}
442
443check_and_log_hs_connectivity()
444{
445	local hssrc=$1
446	local hsdst=$2
447	local tid=$3
448
449	check_hs_ipv6_connectivity ${hssrc} ${hsdst} ${tid}
450	log_test $? 0 "IPv6 Hosts connectivity: hs-t${tid}-${hssrc} -> hs-t${tid}-${hsdst} (tenant ${tid})"
451
452	check_hs_ipv4_connectivity ${hssrc} ${hsdst} ${tid}
453	log_test $? 0 "IPv4 Hosts connectivity: hs-t${tid}-${hssrc} -> hs-t${tid}-${hsdst} (tenant ${tid})"
454
455}
456
457check_and_log_hs_isolation()
458{
459	local hssrc=$1
460	local tidsrc=$2
461	local hsdst=$3
462	local tiddst=$4
463
464	check_hs_ipv6_connectivity ${hssrc} ${hsdst} ${tidsrc}
465	# NOTE: ping should fail
466	log_test $? 1 "IPv6 Hosts isolation: hs-t${tidsrc}-${hssrc} -X-> hs-t${tiddst}-${hsdst}"
467
468	check_hs_ipv4_connectivity ${hssrc} ${hsdst} ${tidsrc}
469	# NOTE: ping should fail
470	log_test $? 1 "IPv4 Hosts isolation: hs-t${tidsrc}-${hssrc} -X-> hs-t${tiddst}-${hsdst}"
471
472}
473
474
475check_and_log_hs2gw_connectivity()
476{
477	local hssrc=$1
478	local tid=$2
479
480	check_hs_ipv6_connectivity ${hssrc} 254 ${tid}
481	log_test $? 0 "IPv6 Hosts connectivity: hs-t${tid}-${hssrc} -> gw (tenant ${tid})"
482
483	check_hs_ipv4_connectivity ${hssrc} 254 ${tid}
484	log_test $? 0 "IPv4 Hosts connectivity: hs-t${tid}-${hssrc} -> gw (tenant ${tid})"
485
486}
487
488router_tests()
489{
490	log_section "IPv6 routers connectivity test"
491
492	check_and_log_rt_connectivity 1 2
493	check_and_log_rt_connectivity 2 1
494}
495
496host2gateway_tests()
497{
498	log_section "IPv4/IPv6 connectivity test among hosts and gateway"
499
500	check_and_log_hs2gw_connectivity 1 100
501	check_and_log_hs2gw_connectivity 2 100
502
503	check_and_log_hs2gw_connectivity 3 200
504	check_and_log_hs2gw_connectivity 4 200
505}
506
507host_vpn_tests()
508{
509	log_section "SRv6 VPN connectivity test among hosts in the same tenant"
510
511	check_and_log_hs_connectivity 1 2 100
512	check_and_log_hs_connectivity 2 1 100
513
514	check_and_log_hs_connectivity 3 4 200
515	check_and_log_hs_connectivity 4 3 200
516}
517
518host_vpn_isolation_tests()
519{
520	local i
521	local j
522	local k
523	local tmp
524	local l1="1 2"
525	local l2="3 4"
526	local t1=100
527	local t2=200
528
529	log_section "SRv6 VPN isolation test among hosts in different tentants"
530
531	for k in 0 1; do
532		for i in ${l1}; do
533			for j in ${l2}; do
534				check_and_log_hs_isolation ${i} ${t1} ${j} ${t2}
535			done
536		done
537
538		# let us test the reverse path
539		tmp="${l1}"; l1="${l2}"; l2="${tmp}"
540		tmp=${t1}; t1=${t2}; t2=${tmp}
541	done
542}
543
544if [ "$(id -u)" -ne 0 ];then
545	echo "SKIP: Need root privileges"
546	exit 0
547fi
548
549if [ ! -x "$(command -v ip)" ]; then
550	echo "SKIP: Could not run test without ip tool"
551	exit 0
552fi
553
554modprobe vrf &>/dev/null
555if [ ! -e /proc/sys/net/vrf/strict_mode ]; then
556        echo "SKIP: vrf sysctl does not exist"
557        exit 0
558fi
559
560cleanup &>/dev/null
561
562setup
563
564router_tests
565host2gateway_tests
566host_vpn_tests
567host_vpn_isolation_tests
568
569print_log_test_results
570
571cleanup &>/dev/null
572
573exit ${ret}
574