[mle] REED to handle rejected ADDR_SOL.rsp (#4834)

Currently, a REED which expects to become Router soon does not send
any SVR_DATA.ntf.  This commit handles rejecting ADDR_SOL.rsp to allow
REED to send SVR_DATA.ntf after it is rejected.

src/core/thread/mle_router.cpp

@@ -74,6 +74,7 @@ MleRouter::MleRouter(Instance &aInstance)
     , mFixedLeaderPartitionId(0)
     , mRouterEligible(true)
     , mAddressSolicitPending(false)
+    , mAddressSolicitRejected(false)
     , mPreviousPartitionIdRouter(0)
     , mPreviousPartitionId(0)
     , mPreviousPartitionRouterIdSequence(0)
@@ -232,6 +233,9 @@ otError MleRouter::HandleChildStart(AttachMode aMode)
 {
     otError error = OT_ERROR_NONE;
 
+    // reset `rejected` flag whenever REED becomes child.
+    mAddressSolicitRejected = false;
+
     mRouterSelectionJitterTimeout = 1 + Random::NonCrypto::GetUint8InRange(0, mRouterSelectionJitter);
 
     StopLeader();
@@ -4033,6 +4037,8 @@ void MleRouter::HandleAddressSolicitResponse(Coap::Message *         aMessage,
 
     if (status != ThreadStatusTlv::kSuccess)
     {
+        mAddressSolicitRejected = true;
+
         if (IsRouterIdValid(mPreviousRouterId))
         {
             if (HasChildren())
@@ -4099,6 +4105,12 @@ exit:
     InformPreviousChannel();
 }
 
+bool MleRouter::IsExpectedToBecomeRouter(void) const
+{
+    return IsRouterEligible() && !IsRouterOrLeader() &&
+           (Get<RouterTable>().GetActiveRouterCount() < GetRouterUpgradeThreshold()) && !mAddressSolicitRejected;
+}
+
 void MleRouter::HandleAddressSolicit(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo)
 {
     static_cast<MleRouter *>(aContext)->HandleAddressSolicit(*static_cast<Coap::Message *>(aMessage),

src/core/thread/mle_router.hpp

@@ -319,6 +319,15 @@ public:
      */
     void SetRouterDowngradeThreshold(uint8_t aThreshold) { mRouterDowngradeThreshold = aThreshold; }
 
+    /**
+     * This method returns if the REED is expected to become Router soon.
+     *
+     * @retval TRUE   If the REED is going to become Router.
+     * @retval FALSE  Otherwise.
+     *
+     */
+    bool IsExpectedToBecomeRouter(void) const;
+
     /**
      * This method removes a link to a neighbor.
      *
@@ -830,6 +839,7 @@ private:
     uint32_t mFixedLeaderPartitionId; ///< only for certification testing
     bool     mRouterEligible : 1;
     bool     mAddressSolicitPending : 1;
+    bool     mAddressSolicitRejected : 1;
 
     uint8_t mRouterId;
     uint8_t mPreviousRouterId;

src/core/thread/network_data_local.cpp

@@ -359,8 +359,7 @@ otError Local::UpdateInconsistentServerData(Coap::ResponseHandler aHandler, void
 #if OPENTHREAD_FTD
 
     // Don't send this Server Data Notification if the device is going to upgrade to Router
-    if (Get<Mle::MleRouter>().IsRouterEligible() && !Get<Mle::MleRouter>().IsRouterOrLeader() &&
+    if (Get<Mle::MleRouter>().IsExpectedToBecomeRouter())
-        (Get<RouterTable>().GetActiveRouterCount() < Get<Mle::MleRouter>().GetRouterUpgradeThreshold()))
     {
         ExitNow(error = OT_ERROR_INVALID_STATE);
     }

tests/scripts/thread-cert/Makefile.am

@@ -157,6 +157,7 @@ EXTRA_DIST                                                         = \
     test_service.py                                                  \
     test_network_data.py                                             \
     test_network_layer.py                                            \
+    test_reed_address_solicit_rejected.py                            \
     tlvs_parsing.py                                                  \
     $(NULL)
 
@@ -179,6 +180,7 @@ check_SCRIPTS                                                      = \
     test_service.py                                                  \
     test_network_data.py                                             \
     test_network_layer.py                                            \
+    test_reed_address_solicit_rejected.py                            \
     Cert_5_1_01_RouterAttach.py                                      \
     Cert_5_1_02_ChildAddressTimeout.py                               \
     Cert_5_1_03_RouterAddressReallocation.py                         \
@@ -290,6 +292,7 @@ XFAIL_NCP_TESTS                                                    = \
     test_diag.py                                                     \
     test_ipv6_fragmentation.py                                       \
     test_ipv6_source_selection.py                                    \
+    test_reed_address_solicit_rejected.py                            \
     test_service.py                                                  \
     Cert_5_3_10_AddressQuery.py                                      \
     Cert_8_1_01_Commissioning.py                                     \

tests/scripts/thread-cert/test_reed_address_solicit_rejected.py

@@ -0,0 +1,122 @@
+#!/usr/bin/env python3
+#
+#  Copyright (c) 2020, 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 config
+import node
+import re
+import unittest
+
+LEADER = 1
+REED = 2
+
+SRV_0_ID = 0
+SRV_0_ENT_NUMBER = '123'
+SRV_0_SERVICE_DATA = 'foo'
+SRV_0_SERVER_DATA = 'bar'
+
+# Topology:
+# LEADER -- REED
+#
+
+
+class TestREEDAddressSolicitRejected(unittest.TestCase):
+
+    def setUp(self):
+        self.simulator = config.create_default_simulator()
+
+        self.nodes = {}
+        for i in [LEADER, REED]:
+            self.nodes[i] = node.Node(i, simulator=self.simulator)
+
+        self.nodes[LEADER].set_panid(0xface)
+        self.nodes[LEADER].set_mode('rsdn')
+
+        self.nodes[REED].set_panid(0xface)
+        self.nodes[REED].set_mode('rsdn')
+        self.nodes[REED].set_router_selection_jitter(1)
+
+    def tearDown(self):
+        for n in list(self.nodes.values()):
+            n.stop()
+            n.destroy()
+        self.simulator.stop()
+
+    def testAddressSolicitRejectedBeforeSvrData(self):
+        self.nodes[LEADER].start()
+        self.nodes[LEADER].set_router_upgrade_threshold(1)
+        self.simulator.go(5)
+        self.assertEqual(self.nodes[LEADER].get_state(), 'leader')
+
+        self.nodes[REED].start()
+        self.simulator.go(5)
+        self.assertEqual(self.nodes[REED].get_state(), 'child')
+
+        self.nodes[REED].add_service(SRV_0_ENT_NUMBER, SRV_0_SERVICE_DATA,
+                                     SRV_0_SERVER_DATA)
+        self.nodes[REED].register_netdata()
+        self.simulator.go(2)
+
+        self.assertEqual(self.hasAloc(REED, SRV_0_ID), True)
+
+    def testAddressSolicitRejectedAfterSvrData(self):
+        self.nodes[LEADER].start()
+        self.nodes[LEADER].set_router_upgrade_threshold(1)
+        self.simulator.go(5)
+        self.assertEqual(self.nodes[LEADER].get_state(), 'leader')
+
+        self.nodes[REED].set_router_selection_jitter(120)
+        self.nodes[REED].start()
+        # set routerupgradethreshold=1 on REED so that it won't send ADDR_SOL.req
+        self.nodes[REED].set_router_upgrade_threshold(1)
+        self.simulator.go(5)
+        self.assertEqual(self.nodes[REED].get_state(), 'child')
+
+        # restore routerupgradethreshold to 16 and add service
+        self.nodes[REED].set_router_upgrade_threshold(16)
+        self.nodes[REED].add_service(SRV_0_ENT_NUMBER, SRV_0_SERVICE_DATA,
+                                     SRV_0_SERVER_DATA)
+        self.nodes[REED].register_netdata()
+        self.simulator.go(130)
+        self.assertEqual(self.hasAloc(REED, SRV_0_ID), True)
+
+    def hasAloc(self, node_id, service_id):
+        for addr in self.nodes[node_id].get_ip6_address(
+                config.ADDRESS_TYPE.ALOC):
+            m = re.match('.*:fc(..)$', addr, re.I)
+            if m is not None:
+                if m.group(
+                        1) == str(service_id +
+                                  10):  # for service_id=3 look for '...:fc13'
+                    return True
+
+        return False
+
+
+if __name__ == '__main__':
+    unittest.main()