[nexus] add 1.4 PIC-TC-1 test for DHCPv6-PD and DNS (openthread#12859)

This commit adds a new Nexus test that implements the test
specification in test-1-4-PIC-TC-1.md. The test verifies Border
Router functionality including:
- DHCPv6-PD client to obtain OMR prefix
- Advertising route to OMR prefix on AIL (Stub Router)
- DNS recursive resolver for public internet addresses
- Connectivity (ICMPv6, UDP, TCP/HTTP) to internet and local servers

New files:
- tests/nexus/test_1_4_PIC_TC_1.cpp: C++ test execution
- tests/nexus/verify_1_4_PIC_TC_1.py: Python pcap verification

Nexus platform enhancements:
- Enabled DHCPv6-PD client in openthread-core-nexus-config.h
- Implemented DHCPv6-PD platform APIs in nexus_infra_if.cpp
- Added RDNSS option to RA in nexus_infra_if.cpp
- Improved packet delivery on infrastructure interface in nexus_core.cpp
- Fixed upstream DNS query matching in nexus_dns.cpp

Author: jwhui

tests/nexus/CMakeLists.txt

@@ -296,6 +296,7 @@ ot_nexus_test(1_4_TREL_TC_6 "cert;nexus")
 ot_nexus_test(1_4_DNS_TC_1 "cert;nexus")
 ot_nexus_test(1_4_DNS_TC_3 "cert;nexus")
 ot_nexus_test(1_4_DNS_TC_5 "cert;nexus")
+ot_nexus_test(1_4_PIC_TC_1 "cert;nexus")
 ot_nexus_test(1_4_CS_TC_3 "cert;nexus")
 
 # Misc tests

tests/nexus/openthread-core-nexus-config.h

@@ -53,7 +53,7 @@
 #define OPENTHREAD_CONFIG_BORDER_AGENT_TXT_DATA_PARSER_ENABLE 1
 #define OPENTHREAD_CONFIG_BORDER_ROUTER_ENABLE 1
 #define OPENTHREAD_CONFIG_BORDER_ROUTING_DHCP6_PD_ENABLE 1
-#define OPENTHREAD_CONFIG_BORDER_ROUTING_DHCP6_PD_CLIENT_ENABLE 0
+#define OPENTHREAD_CONFIG_BORDER_ROUTING_DHCP6_PD_CLIENT_ENABLE 1
 #define OPENTHREAD_CONFIG_BORDER_ROUTING_ENABLE 1
 #define OPENTHREAD_CONFIG_BORDER_ROUTING_TESTING_API_ENABLE 1
 #define OPENTHREAD_CONFIG_BORDER_ROUTING_USE_HEAP_ENABLE 1

tests/nexus/platform/nexus_core.cpp

@@ -648,7 +648,10 @@ void Core::ProcessInfraIf(Node &aNode)
 
         if (!header.GetDestination().IsMulticast())
         {
-            targetNode = FindNodeByInfraIfAddress(header.GetDestination());
+            if (!IsThreadAddress(header.GetDestination()))
+            {
+                targetNode = FindNodeByAddress(header.GetDestination());
+            }
         }
 
         for (Node &rxNode : mNodes)

tests/nexus/platform/nexus_dns.cpp

@@ -110,6 +110,7 @@ void UpstreamDns::StartUpstreamQuery(UpstreamQueryTransaction &aTxn, const Messa
     ot::Dns::Header dnsHeader;
     PendingQuery   *pendingQuery;
     Message        *message = nullptr;
+
     // We use kDnsPort (53) as both source and destination port for upstream queries to simplify interception
     // and response matching in this simulation environment.
 

tests/nexus/platform/nexus_infra_if.cpp

@@ -28,7 +28,8 @@
 
 #include "nexus_infra_if.hpp"
 
-#include "nexus_core.hpp"
+#include <openthread/platform/infra_if.h>
+
 #include "nexus_node.hpp"
 
 namespace ot {
@@ -39,6 +40,8 @@ InfraIf::InfraIf(Instance &aInstance)
     , mIfIndex(0)
     , mUdpHook(nullptr)
     , mHasRioPrefix(false)
+    , mDhcp6PdListening(false)
+    , mIsDnsServer(false)
     , mRaTimer(aInstance)
 {
 }
@@ -196,6 +199,13 @@ void InfraIf::SendRouterAdvertisement(const Ip6::Address &aDestination,
         SuccessOrQuit(ra.AppendRouteInfoOption(*aRioPrefix, 1800, NetworkData::kRoutePreferenceMedium));
     }
 
+    // ETH_2 (Node 4) acts as DNS server
+    if (mIsDnsServer)
+    {
+        const Ip6::Address dnsServerAddr = GetLinkLocalAddress();
+        SuccessOrQuit(ra.AppendRecursiveDnsServerOption(&dnsServerAddr, 1, 1800));
+    }
+
     ra.GetAsPacket(packet);
 
     SendIcmp6Nd(aDestination, packet.GetBytes(), packet.GetLength());
@@ -406,13 +416,30 @@ void InfraIf::SendUdp(const Ip6::Address &aSrcAddress,
     mPendingTxQueue.Enqueue(aPayload);
 }
 
+void InfraIf::SetDhcp6ListeningEnabled(bool aEnable) { mDhcp6PdListening = aEnable; }
+
+void InfraIf::SendDhcp6(Message &aMessage, const Ip6::Address &aDestAddress)
+{
+    SendUdp(SelectSourceAddress(aDestAddress), aDestAddress, Dhcp6::kDhcpClientPort, Dhcp6::kDhcpServerPort, aMessage);
+}
+
 void InfraIf::Receive(Message &aMessage)
 {
     Ip6::Headers headers;
 
     aMessage.SetOffset(0);
     SuccessOrExit(headers.ParseFrom(aMessage));
 
+    if (mDhcp6PdListening && headers.IsUdp() && headers.GetDestinationPort() == Dhcp6::kDhcpClientPort)
+    {
+        Message *payload = aMessage.Clone<kNoReservedHeader>();
+
+        VerifyOrQuit(payload != nullptr);
+        payload->RemoveHeader(sizeof(Ip6::Header) + sizeof(Ip6::Udp::Header));
+        otPlatInfraIfDhcp6PdClientHandleReceived(&GetInstance(), payload, mIfIndex);
+        ExitNow();
+    }
+
     if (headers.IsIcmp6() && (headers.GetDestinationAddress() == Ip6::Address::GetLinkLocalAllNodesMulticast() ||
                               headers.GetDestinationAddress() == Ip6::Address::GetLinkLocalAllRoutersMulticast() ||
                               HasAddress(headers.GetDestinationAddress())))
@@ -648,6 +675,18 @@ otError otPlatGetInfraIfLinkLayerAddress(otInstance                    *aInstanc
     return OT_ERROR_NONE;
 }
 
+void otPlatInfraIfDhcp6PdClientSetListeningEnabled(otInstance *aInstance, bool aEnable, uint32_t aInfraIfIndex)
+{
+    OT_UNUSED_VARIABLE(aInfraIfIndex);
+    AsNode(aInstance).mInfraIf.SetDhcp6ListeningEnabled(aEnable);
+}
+
+void otPlatInfraIfDhcp6PdClientSend(otInstance *aInstance, otMessage *aMessage, otIp6Address *aDest, uint32_t aIfIndex)
+{
+    OT_UNUSED_VARIABLE(aIfIndex);
+    AsNode(aInstance).mInfraIf.SendDhcp6(AsCoreType(aMessage), AsCoreType(aDest));
+}
+
 } // extern "C"
 
 } // namespace Nexus

tests/nexus/platform/nexus_infra_if.hpp

@@ -85,6 +85,10 @@ class InfraIf : public InstanceLocator
 
     void SetEchoReplyHandler(EchoReplyHandler aHandler, void *aContext) { mEchoReplyCallback.Set(aHandler, aContext); }
 
+    void SetDhcp6ListeningEnabled(bool aEnable);
+    void SetIsDnsServer(bool aEnable) { mIsDnsServer = aEnable; }
+    void SendDhcp6(Message &aMessage, const Ip6::Address &aDestAddress);
+
     typedef bool (*UdpHook)(Instance &aInstance, Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
     void SetUdpHook(UdpHook aHook) { mUdpHook = aHook; }
 
@@ -108,6 +112,8 @@ class InfraIf : public InstanceLocator
     Ip6::Prefix mPioPrefix;
     Ip6::Prefix mRioPrefix;
     bool        mHasRioPrefix;
+    bool        mDhcp6PdListening;
+    bool        mIsDnsServer;
 
     using RaTimer = TimerMilliIn<InfraIf, &InfraIf::HandleRaTimer>;
 

tests/nexus/run_nexus_tests.sh

@@ -229,6 +229,7 @@ DEFAULT_TESTS=(
     "1_4_DNS_TC_1"
     "1_4_DNS_TC_3"
     "1_4_DNS_TC_5"
+    "1_4_PIC_TC_1"
     "1_4_CS_TC_3"
 )