From f1e7ceb12ee624188a50fbdadd7e1038bc1cf48e Mon Sep 17 00:00:00 2001
From: Abtin Keshavarzian <abtink@google.com>
Date: Tue, 24 Aug 2021 15:07:26 -0700
Subject: [PATCH] [router-table] fix signalling when neighbor routers are
 removed (#6948)

This commit updates `RouterTable` to ensure signalling removal of
neighbor routers when router table is fully cleared or when a
`Router` with a specific released router ID is cleared.
---
 src/core/thread/router_table.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/core/thread/router_table.cpp b/src/core/thread/router_table.cpp
index 6ab8cc81d..8f777d99b 100644
--- a/src/core/thread/router_table.cpp
+++ b/src/core/thread/router_table.cpp
@@ -89,6 +89,7 @@ exit:
 
 void RouterTable::Clear(void)
 {
+    ClearNeighbors();
     mAllocatedRouterIds.Clear();
     memset(mRouterIdReuseDelay, 0, sizeof(mRouterIdReuseDelay));
     UpdateAllocation();
@@ -265,18 +266,26 @@ Error RouterTable::Release(uint8_t aRouterId)
 {
     Error    error  = kErrorNone;
     uint16_t rloc16 = Mle::Mle::Rloc16FromRouterId(aRouterId);
+    Router * router;
 
     OT_ASSERT(aRouterId <= Mle::kMaxRouterId);
 
     VerifyOrExit(Get<Mle::MleRouter>().IsLeader(), error = kErrorInvalidState);
     VerifyOrExit(IsAllocated(aRouterId), error = kErrorNotFound);
 
+    router = GetNeighbor(rloc16);
+
+    if (router != nullptr)
+    {
+        Get<NeighborTable>().Signal(NeighborTable::kRouterRemoved, *router);
+    }
+
     mAllocatedRouterIds.Remove(aRouterId);
     UpdateAllocation();
 
     mRouterIdReuseDelay[aRouterId] = Mle::kRouterIdReuseDelay;
 
-    for (Router *router = GetFirstEntry(); router != nullptr; router = GetNextEntry(router))
+    for (router = GetFirstEntry(); router != nullptr; router = GetNextEntry(router))
     {
         if (router->GetNextHop() == rloc16)
         {