[nexus] add SRPC-TC-7 for SRP client key persistence (openthread#12788)

This commit adds the Nexus test case 1_3_SRPC_TC_7 which verifies
that a Thread device re-registers its service with the same KEY
record after a reboot, as per the Thread 1.3 test specification.

The implementation includes:
- tests/nexus/test_1_3_SRPC_TC_7.cpp: Executes the test sequence
  by forming a Thread network with a Border Router (BR_1), a Router,
  and a DUT (TD_1). It registers a service on the DUT, simulates a
  reboot using Node::Reset(), and re-registers the same service.
- tests/nexus/verify_1_3_SRPC_TC_7.py: Performs automated verification
  of the captured traffic. It ensures that the SRP Update sent after
  reboot contains a KEY record identical to the one sent before
  reboot. It includes a monkey-patch to access the
  dns.key.public_key field in the packet verifier.
- Integrated the new test into tests/nexus/CMakeLists.txt and
  tests/nexus/run_nexus_tests.sh.

The test validates that the SRP client correctly persists its key
material across reboots, which is essential for maintaining service
registration continuity.

Author: jwhui

tests/nexus/CMakeLists.txt

@@ -278,6 +278,7 @@ ot_nexus_test(1_3_SRP_TC_15 "cert;nexus")
 ot_nexus_test(1_3_SRPC_TC_1 "cert;nexus")
 ot_nexus_test(1_3_SRPC_TC_4 "cert;nexus")
 ot_nexus_test(1_3_SRPC_TC_5 "cert;nexus")
+ot_nexus_test(1_3_SRPC_TC_7 "cert;nexus")
 
 # Misc tests
 ot_nexus_test(border_admitter "core;nexus")

tests/nexus/run_nexus_tests.sh

@@ -213,6 +213,7 @@ DEFAULT_TESTS=(
     "1_3_SRPC_TC_1"
     "1_3_SRPC_TC_4"
     "1_3_SRPC_TC_5"
+    "1_3_SRPC_TC_7"
 )
 
 # Use provided arguments or the default test list

tests/nexus/test_1_3_SRPC_TC_7.cpp

@@ -0,0 +1,247 @@
+/*
+ *  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 "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 a node to join a network, in milliseconds.
+ */
+static constexpr uint32_t kJoinNetworkTime = 10 * 1000;
+
+/**
+ * Time to advance for the network to stabilize, in milliseconds.
+ */
+static constexpr uint32_t kStabilizationTime = 10 * 1000;
+
+/**
+ * Time to wait for SRP registration to complete.
+ */
+static constexpr uint32_t kSrpRegistrationTime = 5 * 1000;
+
+/**
+ * Infrastructure interface index.
+ */
+static constexpr uint32_t kInfraIfIndex = 1;
+
+/**
+ * SRP Lease time in seconds.
+ */
+static constexpr uint32_t kSrpLease1h = 3600;
+
+/**
+ * SRP Key Lease time in seconds.
+ */
+static constexpr uint32_t kSrpKeyLease1d = 86400;
+
+/**
+ * SRP service port.
+ */
+static constexpr uint16_t kSrpServicePort = 33333;
+
+/**
+ * SRP service and host names.
+ */
+static const char kSrpServiceType[]  = "_thread-test._udp";
+static const char kSrpInstanceName[] = "service-test-1";
+static const char kSrpHostName[]     = "host-test-1";
+
+void Test_1_3_SRPC_TC_7(const char *aJsonFileName)
+{
+    /**
+     * 3.7. [1.3] [CERT] [COMPONENT] Thread Device Reboots - Re-registers service with same KEY
+     *
+     * 3.7.1. Purpose
+     * To verify that the Thread Component DUT:
+     * - Is able to re-register a service again after reboot.
+     * - Uses the same key for signing the SRP Update, as indicated in the KEY record.
+     *
+     * 3.7.2. Topology
+     * - BR 1 Border Router Reference Device and Leader
+     * - Router 1-Thread Router reference device
+     * - TD_1 (DUT)-Any Thread Device (FTD or MTD): Thread Component DUT
+     * - Eth 1-IPv6 host reference device on the AIL
+     *
+     * Spec Reference   | V1.1 Section | V1.3.0 Section
+     * -----------------|--------------|---------------
+     * SRP Client       | N/A          | 2.3.2
+     */
+
+    Core nexus;
+
+    Node &br1     = nexus.CreateNode();
+    Node &router1 = nexus.CreateNode();
+    Node &td1     = nexus.CreateNode();
+    Node &eth1    = nexus.CreateNode();
+
+    br1.SetName("BR_1");
+    router1.SetName("Router_1");
+    td1.SetName("TD_1");
+    eth1.SetName("Eth_1");
+
+    SuccessOrQuit(Instance::SetGlobalLogLevel(kLogLevelNote));
+
+    Log("Step 1: Enable & form topology");
+
+    /**
+     * Step 1
+     * - Device: Eth 1, BR 1, Router 1, TD 1
+     * - Description (SRPC-3.7): Enable & form topology
+     * - Pass Criteria:
+     *   - Single Thread Network is formed
+     */
+
+    br1.Form();
+    nexus.AdvanceTime(kFormNetworkTime);
+
+    router1.Join(br1);
+    nexus.AdvanceTime(kJoinNetworkTime);
+
+    td1.Join(br1, Node::kAsFed);
+    nexus.AdvanceTime(kJoinNetworkTime);
+
+    SuccessOrQuit(eth1.Get<Dns::Multicast::Core>().SetEnabled(true, kInfraIfIndex));
+
+    br1.Get<BorderRouter::InfraIf>().Init(kInfraIfIndex, true);
+    br1.Get<BorderRouter::RoutingManager>().Init();
+    SuccessOrQuit(br1.Get<BorderRouter::RoutingManager>().SetEnabled(true));
+
+    SuccessOrQuit(br1.Get<Srp::Server>().SetAddressMode(Srp::Server::kAddressModeUnicast));
+    br1.Get<Srp::Server>().SetEnabled(true);
+
+    nexus.AdvanceTime(kStabilizationTime);
+
+    nexus.AddTestVar("BR_1_MLEID_ADDR", br1.Get<Mle::Mle>().GetMeshLocalEid().ToString().AsCString());
+    nexus.AddTestVar("TD_1_MLEID_ADDR", td1.Get<Mle::Mle>().GetMeshLocalEid().ToString().AsCString());
+    nexus.AddTestVar("TD_1_OMR_ADDR", td1.FindGlobalAddress().ToString().AsCString());
+
+    String<6> portString;
+    portString.Append("%u", br1.Get<Srp::Server>().GetPort());
+    nexus.AddTestVar("BR_1_SRP_PORT", portString.AsCString());
+
+    Log("Step 2: Harness instructs the DUT to register the service");
+
+    /**
+     * Step 2
+     * - Device: TD 1 (DUT)
+     * - Description (SRPC-3.7): Harness instructs the DUT to register the service: $ORIGIN default.service.arpa.
+     *   service-test-1._thread-test._udp ( SRV 33333 host-test-1 ) host-test-1 AAAA <OMR address of TD_1> with the
+     *   following options: Update Lease Option Lease: 60 minutes Key Lease: 1 day
+     * - Pass Criteria:
+     *   - The DUT MUST send an SRP Update to BR_1
+     *   - BR_1 MUST respond Rcode=0 (NoError).
+     */
+
+    td1.Get<Srp::Client>().EnableAutoStartMode(nullptr, nullptr);
+    SuccessOrQuit(td1.Get<Srp::Client>().SetHostName(kSrpHostName));
+    SuccessOrQuit(td1.Get<Srp::Client>().EnableAutoHostAddress());
+    td1.Get<Srp::Client>().SetLeaseInterval(kSrpLease1h);
+    td1.Get<Srp::Client>().SetKeyLeaseInterval(kSrpKeyLease1d);
+
+    {
+        Srp::Client::Service service;
+        ClearAllBytes(service);
+        service.mName         = kSrpServiceType;
+        service.mInstanceName = kSrpInstanceName;
+        service.mPort         = kSrpServicePort;
+        SuccessOrQuit(td1.Get<Srp::Client>().AddService(service));
+    }
+
+    nexus.AdvanceTime(kSrpRegistrationTime);
+
+    VerifyOrQuit(td1.Get<Srp::Client>().GetHostInfo().GetState() == Srp::Client::kRegistered);
+
+    Log("Step 3: Harness instructs device to reboot.");
+
+    /**
+     * Step 3
+     * - Device: TD 1 (DUT)
+     * - Description (SRPC-3.7): Harness instructs device to reboot.
+     * - Pass Criteria:
+     *   - N/A
+     */
+
+    td1.Reset();
+    nexus.AdvanceTime(kStabilizationTime);
+
+    Log("Step 4: (Repeat step 2)");
+
+    /**
+     * Step 4
+     * - Device: TD 1 (DUT)
+     * - Description (SRPC-3.7): (Repeat step 2)
+     * - Pass Criteria:
+     *   - The DUT MUST send an SRP Update to BR_1
+     *   - The KEY record in the SRP Update MUST have an equal value to the KEY record that was sent in step 2
+     *   - BR_1 MUST respond Rcode=0 (NoError).
+     */
+
+    td1.Join(br1, Node::kAsFed);
+    nexus.AdvanceTime(kJoinNetworkTime);
+
+    td1.Get<Srp::Client>().EnableAutoStartMode(nullptr, nullptr);
+    SuccessOrQuit(td1.Get<Srp::Client>().SetHostName(kSrpHostName));
+    SuccessOrQuit(td1.Get<Srp::Client>().EnableAutoHostAddress());
+    td1.Get<Srp::Client>().SetLeaseInterval(kSrpLease1h);
+    td1.Get<Srp::Client>().SetKeyLeaseInterval(kSrpKeyLease1d);
+
+    {
+        Srp::Client::Service service;
+        ClearAllBytes(service);
+        service.mName         = kSrpServiceType;
+        service.mInstanceName = kSrpInstanceName;
+        service.mPort         = kSrpServicePort;
+        SuccessOrQuit(td1.Get<Srp::Client>().AddService(service));
+    }
+
+    nexus.AdvanceTime(kSrpRegistrationTime);
+
+    VerifyOrQuit(td1.Get<Srp::Client>().GetHostInfo().GetState() == Srp::Client::kRegistered);
+
+    nexus.SaveTestInfo(aJsonFileName);
+}
+
+} // namespace Nexus
+} // namespace ot
+
+int main(int argc, char *argv[])
+{
+    ot::Nexus::Test_1_3_SRPC_TC_7((argc > 2) ? argv[2] : "test_1_3_SRPC_TC_7.json");
+    printf("All tests passed\n");
+    return 0;
+}