From cf0640973e9c4686189e16b5582cc42d19cecb39 Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@google.com>
Date: Fri, 19 Feb 2021 09:32:53 -0800
Subject: [PATCH] [bbr] handle case where no PBBR exists in network data
 (#6165)

---
 src/core/backbone_router/bbr_leader.cpp  |  2 +-
 src/core/thread/network_data_service.cpp | 11 +++++------
 src/core/thread/network_data_service.hpp |  5 +----
 3 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/src/core/backbone_router/bbr_leader.cpp b/src/core/backbone_router/bbr_leader.cpp
index e17cf3e76..01a7c37c0 100644
--- a/src/core/backbone_router/bbr_leader.cpp
+++ b/src/core/backbone_router/bbr_leader.cpp
@@ -180,7 +180,7 @@ void Leader::UpdateBackboneRouterPrimary(void)
     State                state;
     uint32_t             origMlrTimeout;
 
-    IgnoreError(Get<NetworkData::Service::Manager>().GetBackboneRouterPrimary(config));
+    Get<NetworkData::Service::Manager>().GetBackboneRouterPrimary(config);
 
     if (config.mServer16 != mConfig.mServer16)
     {
diff --git a/src/core/thread/network_data_service.cpp b/src/core/thread/network_data_service.cpp
index 3fb52fa64..7745d9f3b 100644
--- a/src/core/thread/network_data_service.cpp
+++ b/src/core/thread/network_data_service.cpp
@@ -83,17 +83,18 @@ otError Manager::GetServiceId(uint8_t aServiceNumber, bool aServerStable, uint8_
 
 #if (OPENTHREAD_CONFIG_THREAD_VERSION >= OT_THREAD_VERSION_1_2)
 
-otError Manager::GetBackboneRouterPrimary(ot::BackboneRouter::BackboneRouterConfig &aConfig) const
+void Manager::GetBackboneRouterPrimary(ot::BackboneRouter::BackboneRouterConfig &aConfig) const
 {
-    otError                           error          = OT_ERROR_NOT_FOUND;
     const uint8_t                     serviceData    = BackboneRouter::kServiceNumber;
     const ServerTlv *                 rvalServerTlv  = nullptr;
     const BackboneRouter::ServerData *rvalServerData = nullptr;
     Iterator                          iterator;
 
+    aConfig.mServer16 = Mac::kShortAddrInvalid;
+
     iterator.mServiceTlv = Get<Leader>().FindService(kThreadEnterpriseNumber, &serviceData, sizeof(serviceData));
 
-    VerifyOrExit(iterator.mServiceTlv != nullptr, aConfig.mServer16 = Mac::kShortAddrInvalid);
+    VerifyOrExit(iterator.mServiceTlv != nullptr);
 
     while (IterateToNextServer(iterator) == OT_ERROR_NONE)
     {
@@ -125,10 +126,8 @@ otError Manager::GetBackboneRouterPrimary(ot::BackboneRouter::BackboneRouterConf
     aConfig.mReregistrationDelay = rvalServerData->GetReregistrationDelay();
     aConfig.mMlrTimeout          = rvalServerData->GetMlrTimeout();
 
-    error = OT_ERROR_NONE;
-
 exit:
-    return error;
+    return;
 }
 
 #endif // (OPENTHREAD_CONFIG_THREAD_VERSION >= OT_THREAD_VERSION_1_2)
diff --git a/src/core/thread/network_data_service.hpp b/src/core/thread/network_data_service.hpp
index eb99dbb98..74ed6ecf8 100644
--- a/src/core/thread/network_data_service.hpp
+++ b/src/core/thread/network_data_service.hpp
@@ -323,11 +323,8 @@ public:
      *
      * @param[out]  aConfig      The Primary Backbone Router configuration.
      *
-     * @retval OT_ERROR_NONE       Successfully got the Primary Backbone Router configuration.
-     * @retval OT_ERROR_NOT_FOUND  No Backbone Router Service in the Thread Network.
-     *
      */
-    otError GetBackboneRouterPrimary(ot::BackboneRouter::BackboneRouterConfig &aConfig) const;
+    void GetBackboneRouterPrimary(ot::BackboneRouter::BackboneRouterConfig &aConfig) const;
 #endif
 
     /**