[toranj] Child Supervision test (openthread#2951)

This commit adds a new test-case under `toranj` for Child Supervision
feature.

This test uses MAC whitelisting to emulate the situation where a child
is removed from parent's child table while the child continues to stay
attached to the parent (since data polls from child are acked at radio
platform layer). Specifically the test verifies that once supervision
check is enabled on the child, the child detects that it is no longer
in the parent's table and tries to re-attach. The test verifies the
behavior of both the parent and the child when supervision is enabled.
It verifies that the parent is periodically sending supervision
messages to the child and that the child is monitoring the messages
from parent. This test also indirectly verify the child timeout
behavior on a parent.

tests/toranj/start.sh

@@ -131,6 +131,7 @@ run test-014-ip6-address-add.py
 run test-015-same-prefix-on-multiple-nodes.py
 run test-016-neighbor-table.py
 run test-017-parent-reset-child-recovery.py
+run test-018-child-supervision.py
 run test-019-inform-previous-parent.py
 run test-100-mcu-power-state.py
 run test-600-channel-manager-properties.py

tests/toranj/test-018-child-supervision.py

@@ -0,0 +1,169 @@
+#!/usr/bin/env python
+#
+#  Copyright (c) 2018, The OpenThread Authors.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the
+#     names of its contributors may be used to endorse or promote products
+#     derived from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+
+import time
+import wpan
+from wpan import verify
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Test description: Child Supervision feature
+#
+# This test covers the behavior of Child Supervision feature.
+#
+# This test uses MAC whitelisting to emulate the situation where a child is
+# removed from parent's child table while the child continues to stay attached
+# to the parent (since data polls from child are acked at radio platform layer).
+# Specifically the test verifies that once supervision check is enabled on the
+# child, the child detects that it is no longer present in the parent's table
+# and tries to re-attach.
+
+# The test verifies the behavior of both parent and child, when supervision is
+# enabled. It verifies that parent is periodically sending supervision messages
+# to the child and that the child is monitoring the messages.
+#
+# This test also indirectly verifies the child timeout on parent.
+#
+
+test_name = __file__[:-3] if __file__.endswith('.py') else __file__
+print '-' * 120
+print 'Starting \'{}\''.format(test_name)
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Creating `wpan.Nodes` instances
+
+speedup = 2
+wpan.Node.set_time_speedup_factor(speedup)
+
+parent = wpan.Node()
+child = wpan.Node()
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Init all nodes
+
+wpan.Node.init_all_nodes()
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Build network topology
+
+CHILD_TIMEOUT = 6
+CHILD_SUPERVISION_CHECK_TIMEOUT = 2
+PARENT_SUPERVISION_INTERVAL = 1
+
+child.set(wpan.WPAN_POLL_INTERVAL, '500')
+child.set(wpan.WPAN_THREAD_CHILD_TIMEOUT, str(CHILD_TIMEOUT))
+
+parent.form("child-sup")
+child.join_node(parent, wpan.JOIN_TYPE_SLEEPY_END_DEVICE)
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Test implementation
+
+# Disable child supervision on child and parent
+parent.set(wpan.WPAN_CHILD_SUPERVISION_INTERVAL, '0')
+child.set(wpan.WPAN_CHILD_SUPERVISION_CHECK_TIMEOUT, '0')
+verify(int(parent.get(wpan.WPAN_CHILD_SUPERVISION_INTERVAL), 0) == 0)
+verify(int(child.get(wpan.WPAN_CHILD_SUPERVISION_CHECK_TIMEOUT), 0) == 0)
+
+# Check that the child is associated and has correct timeout
+verify(child.is_associated())
+verify(int(child.get(wpan.WPAN_THREAD_CHILD_TIMEOUT), 0) == CHILD_TIMEOUT)
+
+# Verify the child table on parent contains the child with correct timeout
+child_table = wpan.parse_child_table_result(parent.get(wpan.WPAN_THREAD_CHILD_TABLE))
+verify(len(child_table) == 1)
+verify(int(child_table[0].timeout, 0) == CHILD_TIMEOUT)
+
+# Enabling white-listing on parent
+#
+# Since child is not in parent's whitelist, the data polls from child
+# should be rejected and the child should be removed from parent's
+# child table after timeout. The child however should continue to
+# stay attached (since data polls are acked by radio driver) and
+# supervision check is disabled on the child.
+
+parent.set(wpan.WPAN_MAC_WHITELIST_ENABLED, '1')
+
+def check_child_is_removed_from_parent_child_table():
+	child_table = wpan.parse_child_table_result(parent.get(wpan.WPAN_THREAD_CHILD_TABLE))
+	verify(len(child_table) == 0)
+
+# wait till child is removed from parent's child table
+# after this child should still be associated
+wpan.verify_within(check_child_is_removed_from_parent_child_table, CHILD_TIMEOUT / speedup + 2)
+verify(child.is_associated())
+
+# Enable supervision check on child and expect the child to
+# become detached after the check timeout
+
+child.set(wpan.WPAN_CHILD_SUPERVISION_CHECK_TIMEOUT, str(CHILD_SUPERVISION_CHECK_TIMEOUT))
+
+def check_child_is_detached():
+	verify(not child.is_associated())
+
+wpan.verify_within(check_child_is_detached, CHILD_SUPERVISION_CHECK_TIMEOUT / speedup + 8)
+
+#- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+# Enable child supervision on parent and disable white-listing
+
+parent.set(wpan.WPAN_CHILD_SUPERVISION_INTERVAL, str(PARENT_SUPERVISION_INTERVAL))
+parent.set(wpan.WPAN_MAC_WHITELIST_ENABLED, '0')
+
+# Wait for the child to attach back
+
+def check_child_is_attached():
+	verify(child.is_associated())
+
+wpan.verify_within(check_child_is_attached, 5)
+
+# MAC counters are used to verify the child supervision behavior.
+
+parent_unicast_tx_count = int(parent.get("NCP:Counter:TX_PKT_UNICAST"), 0)
+
+time.sleep(PARENT_SUPERVISION_INTERVAL * 1.2 / speedup)
+
+# To verify that the parent is indeed sending empty "supervision"
+# messages to its child, MAC counter for number of unicast tx is
+# used. Note that supervision interval on parent is set to 1 sec.
+
+verify(int(parent.get("NCP:Counter:TX_PKT_UNICAST"), 0) >= parent_unicast_tx_count + 1)
+
+verify(child.is_associated())
+
+# Disable child supervision on parent
+parent.set(wpan.WPAN_CHILD_SUPERVISION_INTERVAL, '0')
+
+time.sleep(CHILD_SUPERVISION_CHECK_TIMEOUT * 3 / speedup)
+verify(child.is_associated())
+
+#-----------------------------------------------------------------------------------------------------------------------
+# Test finished
+
+wpan.Node.finalize_all_nodes()
+
+print '\'{}\' passed.'.format(test_name)

tests/toranj/wpan.py

@@ -79,6 +79,7 @@
 WPAN_THREAD_NEIGHBOR_TABLE_ASVALMAP            = "Thread:NeighborTable:AsValMap"
 WPAN_THREAD_ROUTER_TABLE                       = "Thread:RouterTable"
 WPAN_THREAD_ROUTER_TABLE_ASVALMAP              = "Thread:RouterTable:AsValMap"
+WPAN_THREAD_CHILD_TIMEOUT                      = "Thread:ChildTimeout"
 WPAN_THREAD_NETWORK_DATA_VERSION               = "Thread:NetworkDataVersion"
 WPAN_THREAD_STABLE_NETWORK_DATA                = "Thread:StableNetworkData"
 WPAN_THREAD_STABLE_NETWORK_DATA_VERSION        = "Thread:StableNetworkDataVersion"