From c98164f9339711cd34c663978ec56c2eb9adc6a0 Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@nestlabs.com>
Date: Wed, 7 Mar 2018 20:12:55 +0000
Subject: [PATCH] [mle] skip IPv6 address registration entries with no matching
 context (#2604)

---
 src/core/thread/mle_router.cpp | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/core/thread/mle_router.cpp b/src/core/thread/mle_router.cpp
index 62c9b9b5e..6945b8fa2 100644
--- a/src/core/thread/mle_router.cpp
+++ b/src/core/thread/mle_router.cpp
@@ -2091,11 +2091,17 @@ otError MleRouter::UpdateChildAddresses(const Message &aMessage, uint16_t aOffse
         VerifyOrExit(aMessage.Read(offset, len, &entry) == len, error = OT_ERROR_PARSE);
 
         offset += len;
+        registeredCount++;
 
         if (entry.IsCompressed())
         {
-            // xxx check if context id exists
-            GetNetif().GetNetworkDataLeader().GetContext(entry.GetContextId(), context);
+            if (GetNetif().GetNetworkDataLeader().GetContext(entry.GetContextId(), context) != OT_ERROR_NONE)
+            {
+                otLogWarnMle(GetInstance(), "Failed to get context %d for compressed address from child 0x%04x",
+                             entry.GetContextId(), aChild.GetRloc16());
+                continue;
+            }
+
             memcpy(&address, context.mPrefix, BitVectorBytes(context.mPrefixLength));
             address.SetIid(entry.GetIid());
         }
@@ -2104,8 +2110,6 @@ otError MleRouter::UpdateChildAddresses(const Message &aMessage, uint16_t aOffse
             address = *entry.GetIp6Address();
         }
 
-        registeredCount++;
-
         // We try to accept/add as many IPv6 addresses as possible.
         // "Child ID/Update Response" will indicate the accepted
         // addresses.