[mac] process security for neighbors on FFD Children (#2373)

src/core/mac/mac.cpp

@@ -1564,8 +1564,39 @@ void Mac::ReceiveDoneTask(Frame *aFrame, otError aError)
     SuccessOrExit(error = aFrame->ValidatePsdu());
 
     aFrame->GetSrcAddr(srcaddr);
+    aFrame->GetDstAddr(dstaddr);
     neighbor = GetNetif().GetMle().GetNeighbor(srcaddr);
 
+    // Destination Address Filtering
+    switch (dstaddr.mLength)
+    {
+    case 0:
+        break;
+
+    case sizeof(ShortAddress):
+        aFrame->GetDstPanId(panid);
+        VerifyOrExit((panid == kShortAddrBroadcast || panid == mPanId) &&
+                     ((mRxOnWhenIdle && dstaddr.mShortAddress == kShortAddrBroadcast) ||
+                      dstaddr.mShortAddress == mShortAddress), error = OT_ERROR_DESTINATION_ADDRESS_FILTERED);
+
+        // Allow  multicasts from neighbor routers if FFD
+        if (neighbor == NULL && dstaddr.mShortAddress == kShortAddrBroadcast &&
+            (GetNetif().GetMle().GetDeviceMode() & Mle::ModeTlv::kModeFFD))
+        {
+            neighbor = GetNetif().GetMle().GetRxOnlyNeighborRouter(srcaddr);
+        }
+
+        break;
+
+    case sizeof(ExtAddress):
+        aFrame->GetDstPanId(panid);
+        VerifyOrExit(panid == mPanId &&
+                     memcmp(&dstaddr.mExtAddress, &mExtAddress, sizeof(dstaddr.mExtAddress)) == 0,
+                     error = OT_ERROR_DESTINATION_ADDRESS_FILTERED);
+        break;
+    }
+
+    // Source Address Filtering
     switch (srcaddr.mLength)
     {
     case 0:
@@ -1613,29 +1644,6 @@ void Mac::ReceiveDoneTask(Frame *aFrame, otError aError)
 
 #endif  // OPENTHREAD_ENABLE_MAC_FILTER
 
-    // Destination Address Filtering
-    aFrame->GetDstAddr(dstaddr);
-
-    switch (dstaddr.mLength)
-    {
-    case 0:
-        break;
-
-    case sizeof(ShortAddress):
-        aFrame->GetDstPanId(panid);
-        VerifyOrExit((panid == kShortAddrBroadcast || panid == mPanId) &&
-                     ((mRxOnWhenIdle && dstaddr.mShortAddress == kShortAddrBroadcast) ||
-                      dstaddr.mShortAddress == mShortAddress), error = OT_ERROR_DESTINATION_ADDRESS_FILTERED);
-        break;
-
-    case sizeof(ExtAddress):
-        aFrame->GetDstPanId(panid);
-        VerifyOrExit(panid == mPanId &&
-                     memcmp(&dstaddr.mExtAddress, &mExtAddress, sizeof(dstaddr.mExtAddress)) == 0,
-                     error = OT_ERROR_DESTINATION_ADDRESS_FILTERED);
-        break;
-    }
-
     // Increment counters
     if (dstaddr.mShortAddress == kShortAddrBroadcast)
     {

src/core/thread/mle_router.cpp

@@ -3300,16 +3300,14 @@ Neighbor *MleRouter::GetNeighbor(uint16_t aAddress)
             }
         }
 
-        for (int i = 0; i <= kMaxRouterId; i++)
+        if (IsActiveRouter(aAddress))
         {
-            if (i == mRouterId)
-            {
-                continue;
-            }
+            uint8_t routerId = GetRouterId(aAddress);
+            Router *router = &mRouters[routerId];
 
-            if (mRouters[i].GetState() == Neighbor::kStateValid && mRouters[i].GetRloc16() == aAddress)
+            if (router->GetState() == Neighbor::kStateValid && router->GetRloc16() == aAddress)
             {
-                ExitNow(rval = &mRouters[i]);
+                ExitNow(rval = router);
             }
         }
 
@@ -3471,6 +3469,54 @@ exit:
     return rval;
 }
 
+Neighbor *MleRouter::GetRxOnlyNeighborRouter(const Mac::Address &aAddress)
+{
+    Neighbor *rval = NULL;
+
+    VerifyOrExit(mRole == OT_DEVICE_ROLE_CHILD, rval = NULL);
+
+    switch (aAddress.mLength)
+    {
+    case sizeof(aAddress.mShortAddress):
+        if (IsActiveRouter(aAddress.mShortAddress))
+        {
+            uint8_t routerId = GetRouterId(aAddress.mShortAddress);
+            Router *router = &mRouters[routerId];
+
+            if (router->GetState() == Neighbor::kStateValid &&
+                router->GetRloc16() == aAddress.mShortAddress)
+            {
+                ExitNow(rval = router);
+            }
+        }
+
+        break;
+
+    case sizeof(aAddress.mExtAddress):
+        for (int i = 0; i <= kMaxRouterId; i++)
+        {
+            if (i == mRouterId)
+            {
+                continue;
+            }
+
+            if (mRouters[i].GetState() == Neighbor::kStateValid &&
+                memcmp(&mRouters[i].GetExtAddress(), &aAddress.mExtAddress, sizeof(aAddress.mExtAddress)) == 0)
+            {
+                ExitNow(rval = &mRouters[i]);
+            }
+        }
+
+        break;
+
+    default:
+        break;
+    }
+
+exit:
+    return rval;
+}
+
 uint16_t MleRouter::GetNextHop(uint16_t aDestination)
 {
     uint8_t destinationId = GetRouterId(aDestination);

src/core/thread/mle_router_ftd.hpp

@@ -503,6 +503,17 @@ public:
      */
     Neighbor *GetNeighbor(const Ip6::Address &aAddress);
 
+    /**
+     * This method returns a pointer to a Neighbor object if a one-way link is maintained
+     * as in the instance of an FFD child with neighbor routers.
+     *
+     * @param[in]  aAddress  The address of the Neighbor.
+     *
+     * @returns A pointer to the Neighbor corresponding to @p aAddress, NULL otherwise.
+     *
+     */
+    Neighbor *GetRxOnlyNeighborRouter(const Mac::Address &aAddress);
+
     /**
      * This method retains diagnostic information for an attached child by Child ID or RLOC16.
      *

src/core/thread/mle_router_mtd.hpp

@@ -101,6 +101,7 @@ public:
     Neighbor *GetNeighbor(const Mac::ExtAddress &aAddress) { return Mle::GetNeighbor(aAddress); }
     Neighbor *GetNeighbor(const Mac::Address &aAddress) { return Mle::GetNeighbor(aAddress); }
     Neighbor *GetNeighbor(const Ip6::Address &aAddress) { return Mle::GetNeighbor(aAddress); }
+    Neighbor *GetRxOnlyNeighborRouter(const Mac::Address &aAddress) { OT_UNUSED_VARIABLE(aAddress); return NULL; }
 
     otError GetNextNeighborInfo(otNeighborInfoIterator &, otNeighborInfo &) { return OT_ERROR_NOT_IMPLEMENTED; }