[nexus] add test 6.4.1 Link-Local Addressing (#12483)

This commit adds a new Nexus test case for 'Link-Local Addressing'
(6.4.1) as specified in the test specification.

Summary of changes:
- Implemented Nexus test 6.4.1:
    - Added tests/nexus/test_6_4_1.cpp: Implements the test execution
      for both Topology A (End Device 'ED_1') and Topology B (Sleepy End
      Device 'SED_1'). The test verifies unicast and multicast ICMPv6 Echo
      Request/Reply using Link-Local addresses. Fragmented and
      non-fragmented packets are tested. The test uses direct method
      calls, sets log level to note, and uses AllowList for
      connectivity.
    - Added tests/nexus/verify_6_4_1.py: PCAP verification script.
      Validates the exchange of ICMPv6 Echo packets for unicast
      (Extended Address-based LLA) and multicast (All Thread Nodes and
      All Nodes) addresses.
- Updated build and execution scripts:
    - Modified tests/nexus/CMakeLists.txt to build the new test.
    - Updated tests/nexus/run_nexus_tests.sh to include 6_4_1 in the
      default test list and added expansion logic for A/B topologies.

tests/nexus/CMakeLists.txt

@@ -167,6 +167,7 @@ ot_nexus_test(6_1_3 "cert;nexus")
 ot_nexus_test(6_1_4 "cert;nexus")
 ot_nexus_test(6_2_1 "cert;nexus")
 ot_nexus_test(6_2_2 "cert;nexus")
+ot_nexus_test(6_4_1 "cert;nexus")
 
 # Misc tests
 ot_nexus_test(border_admitter "core;nexus")

tests/nexus/run_nexus_tests.sh

@@ -101,6 +101,8 @@ DEFAULT_TESTS=(
     "6_2_1_A"
     "6_2_1_B"
     "6_2_2"
+    "6_4_1_A"
+    "6_4_1_B"
 )
 
 # Use provided arguments or the default test list
@@ -192,7 +194,7 @@ run_test()
 expanded_tests=()
 for t in "${TESTS_TO_RUN[@]}"; do
     case "$t" in
-        6_1_1 | 6_1_2 | 6_1_3 | 6_2_1 | 6_2_2)
+        6_1_1 | 6_1_2 | 6_1_3 | 6_2_1 | 6_2_2 | 6_4_1)
             expanded_tests+=("${t}_A" "${t}_B")
             ;;
         *)

tests/nexus/test_6_4_1.cpp

@@ -0,0 +1,266 @@
+/*
+ *  Copyright (c) 2026, 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.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "mac/data_poll_sender.hpp"
+#include "platform/nexus_core.hpp"
+#include "platform/nexus_node.hpp"
+
+namespace ot {
+namespace Nexus {
+
+/**
+ * Time to advance for a node to form a network and become leader, in milliseconds.
+ */
+static constexpr uint32_t kFormNetworkTime = 13 * 1000;
+
+/**
+ * Time to advance for the DUT to attach to the leader, in milliseconds.
+ */
+static constexpr uint32_t kAttachTime = 10 * 1000;
+
+/**
+ * Time to wait for ICMPv6 Echo response, in milliseconds.
+ */
+static constexpr uint32_t kEchoTimeout = 5000;
+
+/**
+ * Data poll period for SED, in milliseconds.
+ */
+static constexpr uint32_t kPollPeriod = 500;
+
+/**
+ * Size of a large (fragmented) ICMPv6 Echo Request payload, in bytes.
+ */
+static constexpr uint16_t kLargePayloadSize = 1200;
+
+/**
+ * Size of a small (non-fragmented) ICMPv6 Echo Request payload, in bytes.
+ */
+static constexpr uint16_t kSmallPayloadSize = 10;
+
+/**
+ * IP Hop Limit for ICMPv6 Echo Request.
+ */
+static constexpr uint8_t kHopLimit = 64;
+
+enum Topology
+{
+    kTopologyA,
+    kTopologyB,
+};
+
+void RunTest6_4_1(Topology aTopology, const char *aJsonFile)
+{
+    /**
+     * 6.4.1 Link-Local Addressing
+     *
+     * 6.4.1.1 Topology
+     * - Topology A: DUT as End Device (ED_1)
+     * - Topology B: DUT as Sleepy End Device (SED_1)
+     * - Leader
+     *
+     * 6.4.1.2 Purpose & Description
+     * The purpose of this test case is to validate the Link-Local addresses that the DUT configures.
+     *
+     * Spec Reference   | V1.1 Section | V1.3.0 Section
+     * -----------------|--------------|---------------
+     * Link-Local Scope | 5.11.1       | 5.11.1
+     */
+
+    Core nexus;
+
+    Node &leader = nexus.CreateNode();
+    Node &dut    = nexus.CreateNode();
+
+    leader.SetName("LEADER");
+
+    if (aTopology == kTopologyA)
+    {
+        dut.SetName("ED_1");
+    }
+    else
+    {
+        dut.SetName("SED_1");
+    }
+
+    nexus.AdvanceTime(0);
+
+    Instance::SetLogLevel(kLogLevelNote);
+
+    if (aTopology == kTopologyA)
+    {
+        Log("---------------------------------------------------------------------------------------");
+        Log("Topology A: ED_1 (DUT)");
+    }
+    else
+    {
+        Log("---------------------------------------------------------------------------------------");
+        Log("Topology B: SED_1 (DUT)");
+    }
+
+    Log("---------------------------------------------------------------------------------------");
+    Log("Step 1: All");
+
+    /**
+     * Step 1: All
+     * - Description: Ensure topology is formed correctly.
+     * - Pass Criteria: N/A
+     */
+    leader.AllowList(dut);
+    dut.AllowList(leader);
+
+    leader.Form();
+    nexus.AdvanceTime(kFormNetworkTime);
+    VerifyOrQuit(leader.Get<Mle::Mle>().IsLeader());
+
+    if (aTopology == kTopologyA)
+    {
+        dut.Join(leader, Node::kAsFed);
+    }
+    else
+    {
+        dut.Join(leader, Node::kAsSed);
+        SuccessOrQuit(dut.Get<DataPollSender>().SetExternalPollPeriod(kPollPeriod));
+    }
+
+    nexus.AdvanceTime(kAttachTime);
+    VerifyOrQuit(dut.Get<Mle::Mle>().IsChild());
+
+    Log("---------------------------------------------------------------------------------------");
+    Log("Step 2: Leader");
+
+    /**
+     * Step 2: Leader
+     * - Description: Harness instructs the device to send a fragmented ICMPv6 Echo Request to the DUT MAC Extended
+     *   Address-based Link-Local address.
+     * - Pass Criteria:
+     *   - The DUT MUST respond with an ICMPv6 Echo Reply.
+     */
+    nexus.SendAndVerifyEchoRequest(leader, dut.Get<Mle::Mle>().GetLinkLocalAddress(), kLargePayloadSize, kHopLimit,
+                                   kEchoTimeout);
+
+    Log("---------------------------------------------------------------------------------------");
+    Log("Step 3: Leader");
+
+    /**
+     * Step 3: Leader
+     * - Description: Harness instructs the device to send an ICMPv6 Echo Request to the DUT MAC Extended
+     *   Address-based Link-Local address.
+     * - Pass Criteria:
+     *   - The DUT MUST respond with an ICMPv6 Echo Reply.
+     */
+    nexus.SendAndVerifyEchoRequest(leader, dut.Get<Mle::Mle>().GetLinkLocalAddress(), kSmallPayloadSize, kHopLimit,
+                                   kEchoTimeout);
+
+    Log("---------------------------------------------------------------------------------------");
+    Log("Step 4: Leader");
+
+    /**
+     * Step 4: Leader
+     * - Description: Harness instructs the device to send a fragmented ICMPv6 Echo Request to the Link-Local All
+     *   Thread Nodes multicast address.
+     * - Pass Criteria:
+     *   - The DUT MUST respond with an ICMPv6 Echo Reply.
+     */
+    nexus.SendAndVerifyEchoRequest(leader, leader.Get<Mle::Mle>().GetLinkLocalAllThreadNodesAddress(),
+                                   kLargePayloadSize, kHopLimit, kEchoTimeout);
+
+    Log("---------------------------------------------------------------------------------------");
+    Log("Step 5: Leader");
+
+    /**
+     * Step 5: Leader
+     * - Description: Harness instructs the device to send an ICMPv6 Echo Request to the Link-Local All Thread Nodes
+     *   multicast address.
+     * - Pass Criteria:
+     *   - The DUT MUST respond with an ICMPv6 Echo Reply.
+     */
+    nexus.SendAndVerifyEchoRequest(leader, leader.Get<Mle::Mle>().GetLinkLocalAllThreadNodesAddress(),
+                                   kSmallPayloadSize, kHopLimit, kEchoTimeout);
+
+    if (aTopology == kTopologyA)
+    {
+        Log("---------------------------------------------------------------------------------------");
+        Log("Step 6: [Topology A only] Leader");
+
+        /**
+         * Step 6: [Topology A only] Leader
+         * - Description: Harness instructs the device to send a fragmented ICMPv6 Echo Request to the Link-Local All
+         *   Nodes multicast address (FF02::1).
+         * - Pass Criteria:
+         *   - The DUT MUST respond with an ICMPv6 Echo Reply.
+         */
+        nexus.SendAndVerifyEchoRequest(leader, Ip6::Address::GetLinkLocalAllNodesMulticast(), kLargePayloadSize,
+                                       kHopLimit, kEchoTimeout);
+
+        Log("---------------------------------------------------------------------------------------");
+        Log("Step 7: [Topology A only] Leader");
+
+        /**
+         * Step 7: [Topology A only] Leader
+         * - Description: Harness instructs the device to send an ICMPv6 Echo Request to the Link-Local All Nodes
+         *   multicast address (FF02::1).
+         * - Pass Criteria:
+         *   - The DUT MUST respond with an ICMPv6 Echo Reply.
+         */
+        nexus.SendAndVerifyEchoRequest(leader, Ip6::Address::GetLinkLocalAllNodesMulticast(), kSmallPayloadSize,
+                                       kHopLimit, kEchoTimeout);
+    }
+
+    nexus.SaveTestInfo(aJsonFile);
+}
+
+} // namespace Nexus
+} // namespace ot
+
+int main(int argc, char *argv[])
+{
+    if (argc < 2)
+    {
+        ot::Nexus::RunTest6_4_1(ot::Nexus::kTopologyB, "test_6_4_1.json");
+    }
+    else if (strcmp(argv[1], "A") == 0)
+    {
+        ot::Nexus::RunTest6_4_1(ot::Nexus::kTopologyA, (argc > 2) ? argv[2] : "test_6_4_1.json");
+    }
+    else if (strcmp(argv[1], "B") == 0)
+    {
+        ot::Nexus::RunTest6_4_1(ot::Nexus::kTopologyB, (argc > 2) ? argv[2] : "test_6_4_1.json");
+    }
+    else
+    {
+        fprintf(stderr, "Error: Invalid topology '%s'. Must be 'A' or 'B'.\n", argv[1]);
+        return 1;
+    }
+
+    printf("All tests passed\n");
+    return 0;
+}

tests/nexus/verify_6_4_1.py

@@ -0,0 +1,175 @@
+#!/usr/bin/env python3
+#
+#  Copyright (c) 2026, 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 sys
+import os
+
+# Add the current directory to sys.path to find verify_utils
+CUR_DIR = os.path.dirname(os.path.abspath(__file__))
+sys.path.append(CUR_DIR)
+
+import verify_utils
+from pktverify import consts
+
+
+def verify(pv):
+    # 6.4.1 Link-Local Addressing
+    #
+    # 6.4.1.1 Topology
+    # - Topology A: DUT as End Device (ED_1)
+    # - Topology B: DUT as Sleepy End Device (SED_1)
+    # - Leader
+    #
+    # 6.4.1.2 Purpose & Description
+    # The purpose of this test case is to validate the Link-Local addresses that the DUT configures.
+    #
+    # Spec Reference   | V1.1 Section | V1.3.0 Section
+    # -----------------|--------------|---------------
+    # Link-Local Scope | 5.11.1       | 5.11.1
+
+    pkts = pv.pkts
+    pv.summary.show()
+
+    LEADER = pv.vars['LEADER']
+    DUT = pv.vars.get('ED_1') or pv.vars.get('SED_1') or pv.vars.get('DUT')
+    DUT_LLA = pv.vars.get('ED_1_LLA') or pv.vars.get('SED_1_LLA') or pv.vars.get('DUT_LLA')
+
+    assert DUT is not None, "DUT not found"
+    assert DUT_LLA is not None, "DUT_LLA not found"
+
+    # Step 1: All
+    # - Description: Ensure topology is formed correctly.
+    # - Pass Criteria: N/A
+    print("Step 1: All - Ensure topology is formed correctly.")
+
+    # Step 2: Leader
+    # - Description: Harness instructs the device to send a fragmented ICMPv6 Echo Request to the DUT MAC Extended
+    #   Address-based Link-Local address.
+    # - Pass Criteria:
+    #   - The DUT MUST respond with an ICMPv6 Echo Reply.
+    print("Step 2: Leader sends a fragmented ICMPv6 Echo Request to the DUT Link-Local address.")
+    _pkt = pkts.filter_ping_request().\
+        filter_wpan_src64(LEADER).\
+        filter_ipv6_dst(DUT_LLA).\
+        filter(lambda p: p.ipv6.plen > 1000).\
+        must_next()
+    pkts.filter_ping_reply(identifier=_pkt.icmpv6.echo.identifier).\
+        filter_wpan_src64(DUT).\
+        filter_ipv6_src(DUT_LLA).\
+        must_next()
+
+    # Step 3: Leader
+    # - Description: Harness instructs the device to send an ICMPv6 Echo Request to the DUT MAC Extended
+    #   Address-based Link-Local address.
+    # - Pass Criteria:
+    #   - The DUT MUST respond with an ICMPv6 Echo Reply.
+    print("Step 3: Leader sends an ICMPv6 Echo Request to the DUT Link-Local address.")
+    _pkt = pkts.filter_ping_request().\
+        filter_wpan_src64(LEADER).\
+        filter_ipv6_dst(DUT_LLA).\
+        filter(lambda p: p.ipv6.plen < 100).\
+        must_next()
+    pkts.filter_ping_reply(identifier=_pkt.icmpv6.echo.identifier).\
+        filter_wpan_src64(DUT).\
+        filter_ipv6_src(DUT_LLA).\
+        must_next()
+
+    # Step 4: Leader
+    # - Description: Harness instructs the device to send a fragmented ICMPv6 Echo Request to the Link-Local All
+    #   Thread Nodes multicast address.
+    # - Pass Criteria:
+    #   - The DUT MUST respond with an ICMPv6 Echo Reply.
+    print(
+        "Step 4: Leader sends a fragmented ICMPv6 Echo Request to the Link-Local All Thread Nodes multicast address.")
+    _pkt = pkts.filter_ping_request().\
+        filter_wpan_src64(LEADER).\
+        filter_ipv6_dst(consts.LINK_LOCAL_All_THREAD_NODES_MULTICAST_ADDRESS).\
+        filter(lambda p: p.ipv6.plen > 1000).\
+        must_next()
+    pkts.filter_ping_reply(identifier=_pkt.icmpv6.echo.identifier).\
+        filter_wpan_src64(DUT).\
+        filter_ipv6_src(DUT_LLA).\
+        must_next()
+
+    # Step 5: Leader
+    # - Description: Harness instructs the device to send an ICMPv6 Echo Request to the Link-Local All Thread Nodes
+    #   multicast address.
+    # - Pass Criteria:
+    #   - The DUT MUST respond with an ICMPv6 Echo Reply.
+    print("Step 5: Leader sends an ICMPv6 Echo Request to the Link-Local All Thread Nodes multicast address.")
+    _pkt = pkts.filter_ping_request().\
+        filter_wpan_src64(LEADER).\
+        filter_ipv6_dst(consts.LINK_LOCAL_All_THREAD_NODES_MULTICAST_ADDRESS).\
+        filter(lambda p: p.ipv6.plen < 100).\
+        must_next()
+    pkts.filter_ping_reply(identifier=_pkt.icmpv6.echo.identifier).\
+        filter_wpan_src64(DUT).\
+        filter_ipv6_src(DUT_LLA).\
+        must_next()
+
+    # Step 6: [Topology A only] Leader
+    # - Description: Harness instructs the device to send a fragmented ICMPv6 Echo Request to the Link-Local All Nodes
+    #   multicast address (FF02::1).
+    # - Pass Criteria:
+    #   - The DUT MUST respond with an ICMPv6 Echo Reply.
+    is_topology_a = 'ED_1' in pv.vars
+
+    if is_topology_a:
+        print("Step 6: Leader sends a fragmented ICMPv6 Echo Request to the Link-Local All Nodes multicast address.")
+        _pkt = pkts.filter_ping_request().\
+            filter_wpan_src64(LEADER).\
+            filter_ipv6_dst(consts.LINK_LOCAL_ALL_NODES_MULTICAST_ADDRESS).\
+            filter(lambda p: p.ipv6.plen > 1000).\
+            next()
+        if _pkt:
+            pkts.filter_ping_reply(identifier=_pkt.icmpv6.echo.identifier).\
+                filter_wpan_src64(DUT).\
+                filter_ipv6_src(DUT_LLA).\
+                must_next()
+
+        # Step 7: [Topology A only] Leader
+        # - Description: Harness instructs the device to send an ICMPv6 Echo Request to the Link-Local All Nodes
+        #   multicast address (FF02::1).
+        # - Pass Criteria:
+        #   - The DUT MUST respond with an ICMPv6 Echo Reply.
+        print("Step 7: Leader sends an ICMPv6 Echo Request to the Link-Local All Nodes multicast address.")
+        _pkt = pkts.filter_ping_request().\
+            filter_wpan_src64(LEADER).\
+            filter_ipv6_dst(consts.LINK_LOCAL_ALL_NODES_MULTICAST_ADDRESS).\
+            filter(lambda p: p.ipv6.plen < 100).\
+            next()
+        if _pkt:
+            pkts.filter_ping_reply(identifier=_pkt.icmpv6.echo.identifier).\
+                filter_wpan_src64(DUT).\
+                filter_ipv6_src(DUT_LLA).\
+                must_next()
+
+
+if __name__ == '__main__':
+    verify_utils.run_main(verify)