Commit e6991384 authored by Vladimir Oltean's avatar Vladimir Oltean Committed by Jakub Kicinski
Browse files

selftests: forwarding: add a test for MAC Merge layer 



The MAC Merge layer (IEEE 802.3-2018 clause 99) does all the heavy
lifting for Frame Preemption (IEEE 802.1Q-2018 clause 6.7.2), a TSN
feature for minimizing latency.

Preemptible traffic is different on the wire from normal traffic in
incompatible ways. If we send a preemptible packet and the link partner
doesn't support preemption, it will drop it as an error frame and we
will never know. The MAC Merge layer has a control plane of its own,
which can be manipulated (using ethtool) in order to negotiate this
capability with the link partner (through LLDP).

Actually the TLV format for LLDP solves this problem only partly,
because both partners only advertise:
- if they support preemption (RX and TX)
- if they have enabled preemption (TX)
so we cannot tell the link partner what to do - we cannot force it to
enable reception of our preemptible packets.

That is fully solved by the verification feature, where the local device
generates some small probe frames which look like preemptible frames
with no useful content, and the link partner is obliged to respond to
them if it supports the standard. If the verification times out, we know
that preemption isn't active in our TX direction on the link.

Having clarified the definition, this selftest exercises the manual
(ethtool) configuration path of 2 link partners (with and without
verification), and the LLDP code path, using the openlldp project.

The test also verifies the TX activity of the MAC Merge layer by
sending traffic through a traffic class configured as preemptible
(using mqprio). There isn't a good way to make this really portable
(user space cannot find out how many traffic classes there are for
a device), but I chose num_tc 4 here, that should work reasonably well.
I also know that some devices (stmmac) only permit TXQ0 to be
preemptible, so this is why PREEMPTIBLE_PRIO was strategically chosen
as 0. Even if other hardware is more configurable, this test should
cover the baseline.

This is not really a "forwarding" selftest, but I put it near the other
"ethtool" selftests.

$ ./ethtool_mm.sh eno0 swp0
TEST: Manual configuration with verification: eno0 to swp0          [ OK ]
TEST: Manual configuration with verification: swp0 to eno0          [ OK ]
TEST: Manual configuration without verification: eno0 to swp0       [ OK ]
TEST: Manual configuration without verification: swp0 to eno0       [ OK ]
TEST: Manual configuration with failed verification: eno0 to swp0   [ OK ]
TEST: Manual configuration with failed verification: swp0 to eno0   [ OK ]
TEST: LLDP                                                          [ OK ]

Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent b5bf7126

tools/testing/selftests/net/forwarding/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ TEST_PROGS = bridge_igmp.sh \ 
	custom_multipath_hash.sh \

	dual_vxlan_bridge.sh \

	ethtool_extended_state.sh \

	ethtool_mm.sh \

	ethtool.sh \

	gre_custom_multipath_hash.sh \

	gre_inner_v4_multipath.sh \

tools/testing/selftests/net/forwarding/ethtool_mm.sh

0 → 100755
+288 −0
Original line number Diff line number Diff line 
#!/bin/bash

# SPDX-License-Identifier: GPL-2.0



ALL_TESTS="

	manual_with_verification_h1_to_h2

	manual_with_verification_h2_to_h1

	manual_without_verification_h1_to_h2

	manual_without_verification_h2_to_h1

	manual_failed_verification_h1_to_h2

	manual_failed_verification_h2_to_h1

	lldp

"



NUM_NETIFS=2

REQUIRE_MZ=no

PREEMPTIBLE_PRIO=0

source lib.sh



traffic_test()

{

	local if=$1; shift

	local src=$1; shift

	local num_pkts=10000

	local before=

	local after=

	local delta=



	before=$(ethtool_std_stats_get $if "eth-mac" "FramesTransmittedOK" $src)



	$MZ $if -q -c $num_pkts -p 64 -b bcast -t ip -R $PREEMPTIBLE_PRIO



	after=$(ethtool_std_stats_get $if "eth-mac" "FramesTransmittedOK" $src)



	delta=$((after - before))



	# Allow an extra 1% tolerance for random packets sent by the stack

	[ $delta -ge $num_pkts ] && [ $delta -le $((num_pkts + 100)) ]

}



manual_with_verification()

{

	local tx=$1; shift

	local rx=$1; shift



	RET=0



	# It isn't completely clear from IEEE 802.3-2018 Figure 99-5: Transmit

	# Processing state diagram whether the "send_r" variable (send response

	# to verification frame) should be taken into consideration while the

	# MAC Merge TX direction is disabled. That being said, at least the

	# NXP ENETC does not, and requires tx-enabled on in order to respond to

	# the link partner's verification frames.

	ethtool --set-mm $rx tx-enabled on

	ethtool --set-mm $tx verify-enabled on tx-enabled on



	# Wait for verification to finish

	sleep 1



	ethtool --json --show-mm $tx | jq -r '.[]."verify-status"' | \

		grep -q 'SUCCEEDED'

	check_err "$?" "Verification did not succeed"



	ethtool --json --show-mm $tx | jq -r '.[]."tx-active"' | grep -q 'true'

	check_err "$?" "pMAC TX is not active"



	traffic_test $tx "pmac"

	check_err "$?" "Traffic did not get sent through $tx's pMAC"



	ethtool --set-mm $tx verify-enabled off tx-enabled off

	ethtool --set-mm $rx tx-enabled off



	log_test "Manual configuration with verification: $tx to $rx"

}



manual_with_verification_h1_to_h2()

{

	manual_with_verification $h1 $h2

}



manual_with_verification_h2_to_h1()

{

	manual_with_verification $h2 $h1

}



manual_without_verification()

{

	local tx=$1; shift

	local rx=$1; shift



	RET=0



	ethtool --set-mm $tx verify-enabled off tx-enabled on



	ethtool --json --show-mm $tx | jq -r '.[]."verify-status"' | \

		grep -q 'DISABLED'

	check_err "$?" "Verification is not disabled"



	ethtool --json --show-mm $tx | jq -r '.[]."tx-active"' | grep -q 'true'

	check_err "$?" "pMAC TX is not active"



	traffic_test $tx "pmac"

	check_err "$?" "Traffic did not get sent through $tx's pMAC"



	ethtool --set-mm $tx verify-enabled off tx-enabled off



	log_test "Manual configuration without verification: $tx to $rx"

}



manual_without_verification_h1_to_h2()

{

	manual_without_verification $h1 $h2

}



manual_without_verification_h2_to_h1()

{

	manual_without_verification $h2 $h1

}



manual_failed_verification()

{

	local tx=$1; shift

	local rx=$1; shift



	RET=0



	ethtool --set-mm $rx pmac-enabled off

	ethtool --set-mm $tx verify-enabled on tx-enabled on



	# Wait for verification to time out

	sleep 1



	ethtool --json --show-mm $tx | jq -r '.[]."verify-status"' | \

		grep -q 'SUCCEEDED'

	check_fail "$?" "Verification succeeded when it shouldn't have"



	ethtool --json --show-mm $tx | jq -r '.[]."tx-active"' | grep -q 'true'

	check_fail "$?" "pMAC TX is active when it shouldn't have"



	traffic_test $tx "emac"

	check_err "$?" "Traffic did not get sent through $tx's eMAC"



	ethtool --set-mm $tx verify-enabled off tx-enabled off

	ethtool --set-mm $rx pmac-enabled on



	log_test "Manual configuration with failed verification: $tx to $rx"

}



manual_failed_verification_h1_to_h2()

{

	manual_failed_verification $h1 $h2

}



manual_failed_verification_h2_to_h1()

{

	manual_failed_verification $h2 $h1

}



lldp_change_add_frag_size()

{

	local add_frag_size=$1



	lldptool -T -i $h1 -V addEthCaps addFragSize=$add_frag_size >/dev/null

	# Wait for TLVs to be received

	sleep 2

	lldptool -i $h2 -t -n -V addEthCaps | \

		grep -q "Additional fragment size: $add_frag_size"

}



lldp()

{

	RET=0



	systemctl start lldpad



	# Configure the interfaces to receive and transmit LLDPDUs

	lldptool -L -i $h1 adminStatus=rxtx >/dev/null

	lldptool -L -i $h2 adminStatus=rxtx >/dev/null



	# Enable the transmission of Additional Ethernet Capabilities TLV

	lldptool -T -i $h1 -V addEthCaps enableTx=yes >/dev/null

	lldptool -T -i $h2 -V addEthCaps enableTx=yes >/dev/null



	# Wait for TLVs to be received

	sleep 2



	lldptool -i $h1 -t -n -V addEthCaps | \

		grep -q "Preemption capability active"

	check_err "$?" "$h1 pMAC TX is not active"



	lldptool -i $h2 -t -n -V addEthCaps | \

		grep -q "Preemption capability active"

	check_err "$?" "$h2 pMAC TX is not active"



	lldp_change_add_frag_size 3

	check_err "$?" "addFragSize 3"



	lldp_change_add_frag_size 2

	check_err "$?" "addFragSize 2"



	lldp_change_add_frag_size 1

	check_err "$?" "addFragSize 1"



	lldp_change_add_frag_size 0

	check_err "$?" "addFragSize 0"



	traffic_test $h1 "pmac"

	check_err "$?" "Traffic did not get sent through $h1's pMAC"



	traffic_test $h2 "pmac"

	check_err "$?" "Traffic did not get sent through $h2's pMAC"



	systemctl stop lldpad



	log_test "LLDP"

}



h1_create()

{

	ip link set dev $h1 up



	tc qdisc add dev $h1 root mqprio num_tc 4 map 0 1 2 3 \

		queues 1@0 1@1 1@2 1@3 \

		fp P E E E \

		hw 1



	ethtool --set-mm $h1 pmac-enabled on tx-enabled off verify-enabled off

}



h2_create()

{

	ip link set dev $h2 up



	ethtool --set-mm $h2 pmac-enabled on tx-enabled off verify-enabled off



	tc qdisc add dev $h2 root mqprio num_tc 4 map 0 1 2 3 \

		queues 1@0 1@1 1@2 1@3 \

		fp P E E E \

		hw 1

}



h1_destroy()

{

	ethtool --set-mm $h1 pmac-enabled off tx-enabled off verify-enabled off



	tc qdisc del dev $h1 root



	ip link set dev $h1 down

}



h2_destroy()

{

	tc qdisc del dev $h2 root



	ethtool --set-mm $h2 pmac-enabled off tx-enabled off verify-enabled off



	ip link set dev $h2 down

}



setup_prepare()

{

	check_ethtool_mm_support

	check_tc_fp_support

	require_command lldptool

	bail_on_lldpad "autoconfigure the MAC Merge layer" "configure it manually"



	h1=${NETIFS[p1]}

	h2=${NETIFS[p2]}



	h1_create

	h2_create

}



cleanup()

{

	pre_cleanup



	h2_destroy

	h1_destroy

}



trap cleanup EXIT



setup_prepare

setup_wait



tests_run



exit $EXIT_STATUS

tools/testing/selftests/net/forwarding/lib.sh

+18 −0
Original line number Diff line number Diff line
@@ -120,6 +120,15 @@ check_tc_action_hw_stats_support() 
	fi

}



check_tc_fp_support()

{

	tc qdisc add dev lo mqprio help 2>&1 | grep -q "fp "

	if [[ $? -ne 0 ]]; then

		echo "SKIP: iproute2 too old; tc is missing frame preemption support"

		exit $ksft_skip

	fi

}



check_ethtool_lanes_support()

{

	ethtool --help 2>&1| grep lanes &> /dev/null
@@ -129,6 +138,15 @@ check_ethtool_lanes_support() 
	fi

}



check_ethtool_mm_support()

{

	ethtool --help 2>&1| grep -- '--show-mm' &> /dev/null

	if [[ $? -ne 0 ]]; then

		echo "SKIP: ethtool too old; it is missing MAC Merge layer support"

		exit $ksft_skip

	fi

}



check_locked_port_support()

{

	if ! bridge -d link show | grep -q " locked"; then