From a534551efefedab2fe2691ca4b9f51cdf9b7893b Mon Sep 17 00:00:00 2001
From: Abtin Keshavarzian <abtink@google.com>
Date: Thu, 2 Oct 2025 11:02:48 -0700
Subject: [PATCH] [border-agent] read NetName and XPanId from active dataset
 for TXT data (#11989)

This change updates `BorderAgent::PrepareServiceTxtData()` to read the
Network Name (`nn` key) and Extended PAN ID (`xp` key) from the
Active Dataset, after verifying that the dataset is valid and has an
active timestamp.

Previously, these values were read directly from `NetworkNameManager`
and `ExtendedPanIdManager`, which could provide default or initial
values (during stack initialization). Reading from the Active Dataset
ensures that the advertised service TXT data is consistent with the
dataset currently in use by the device.

The `ValidateMeshCoPTxtData()` test is updated to reflect this
behavior.
---
 src/core/meshcop/border_agent.cpp | 23 ++++++++++++++++++-----
 tests/nexus/test_border_agent.cpp |  8 ++++++--
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/core/meshcop/border_agent.cpp b/src/core/meshcop/border_agent.cpp
index 8a9a85d44..d8df76a29 100644
--- a/src/core/meshcop/border_agent.cpp
+++ b/src/core/meshcop/border_agent.cpp
@@ -526,8 +526,9 @@ Error BorderAgent::PrepareServiceTxtData(ServiceTxtData &aTxtData)
 
 Error BorderAgent::PrepareServiceTxtData(uint8_t *aBuffer, uint16_t aBufferSize, uint16_t &aLength)
 {
-    Error               error = kErrorNone;
-    Dns::TxtDataEncoder encoder(aBuffer, aBufferSize);
+    Error                  error = kErrorNone;
+    Dns::TxtDataEncoder    encoder(aBuffer, aBufferSize);
+    MeshCoP::Dataset::Info datasetInfo;
 
 #if OPENTHREAD_CONFIG_BORDER_AGENT_ID_ENABLE
     {
@@ -538,11 +539,23 @@ Error BorderAgent::PrepareServiceTxtData(uint8_t *aBuffer, uint16_t aBufferSize,
     }
 #endif
     SuccessOrExit(error = encoder.AppendStringEntry("rv", kTxtDataRecordVersion));
-    SuccessOrExit(error = encoder.AppendNameEntry("nn", Get<NetworkNameManager>().GetNetworkName().GetAsData()));
-    SuccessOrExit(error = encoder.AppendEntry("xp", Get<ExtendedPanIdManager>().GetExtPanId()));
+    SuccessOrExit(error = encoder.AppendBigEndianUintEntry("sb", DetermineStateBitmap()));
     SuccessOrExit(error = encoder.AppendStringEntry("tv", kThreadVersionString));
     SuccessOrExit(error = encoder.AppendEntry("xa", Get<Mac::Mac>().GetExtAddress()));
-    SuccessOrExit(error = encoder.AppendBigEndianUintEntry("sb", DetermineStateBitmap()));
+
+    if (Get<MeshCoP::ActiveDatasetManager>().IsComplete() &&
+        (Get<MeshCoP::ActiveDatasetManager>().Read(datasetInfo) == kErrorNone))
+    {
+        if (datasetInfo.IsPresent<Dataset::kExtendedPanId>())
+        {
+            SuccessOrExit(error = encoder.AppendEntry("xp", datasetInfo.Get<Dataset::kExtendedPanId>()));
+        }
+
+        if (datasetInfo.IsPresent<Dataset::kNetworkName>())
+        {
+            SuccessOrExit(error = encoder.AppendNameEntry("nn", datasetInfo.Get<Dataset::kNetworkName>().GetAsData()));
+        }
+    }
 
     if (Get<Mle::Mle>().IsAttached())
     {
diff --git a/tests/nexus/test_border_agent.cpp b/tests/nexus/test_border_agent.cpp
index 251daf6d2..51fe3502c 100644
--- a/tests/nexus/test_border_agent.cpp
+++ b/tests/nexus/test_border_agent.cpp
@@ -1251,11 +1251,15 @@ void ValidateMeshCoPTxtData(TxtData &aTxtData, Node &aNode)
     aNode.Get<BorderAgent>().GetId(id);
     aTxtData.ValidateKey("id", id);
     aTxtData.ValidateKey("rv", "1");
-    aTxtData.ValidateKey("nn", aNode.Get<NetworkNameManager>().GetNetworkName().GetAsCString());
-    aTxtData.ValidateKey("xp", aNode.Get<ExtendedPanIdManager>().GetExtPanId());
     aTxtData.ValidateKey("tv", kThreadVersionString);
     aTxtData.ValidateKey("xa", aNode.Get<Mac::Mac>().GetExtAddress());
 
+    if (aNode.Get<MeshCoP::ActiveDatasetManager>().IsComplete())
+    {
+        aTxtData.ValidateKey("nn", aNode.Get<NetworkNameManager>().GetNetworkName().GetAsCString());
+        aTxtData.ValidateKey("xp", aNode.Get<ExtendedPanIdManager>().GetExtPanId());
+    }
+
     if (aNode.Get<Mle::Mle>().IsAttached())
     {
         aTxtData.ValidateKey("pt", BigEndian::HostSwap32(aNode.Get<Mle::Mle>().GetLeaderData().GetPartitionId()));