Apply realm-local scope to mesh-local addresses for source address selection. (#1000)

include/openthread-types.h

@@ -897,11 +897,13 @@ typedef struct otBufferInfo
  */
 typedef struct otNetifAddress
 {
-    otIp6Address           mAddress;            ///< The IPv6 unicast address.
+    otIp6Address           mAddress;                 ///< The IPv6 unicast address.
-    uint32_t               mPreferredLifetime;  ///< The Preferred Lifetime.
+    uint32_t               mPreferredLifetime;       ///< The Preferred Lifetime.
-    uint32_t               mValidLifetime;      ///< The Valid lifetime.
+    uint32_t               mValidLifetime;           ///< The Valid lifetime.
-    uint8_t                mPrefixLength;       ///< The Prefix length.
+    uint8_t                mPrefixLength;            ///< The Prefix length.
-    struct otNetifAddress *mNext;               ///< A pointer to the next network interface address.
+    unsigned int           mScopeOverride : 4;       ///< The IPv6 scope of this address.
+    bool                   mScopeOverrideValid : 1;  ///< TRUE if the mScopeOverride value is valid, FALSE othewrise.
+    struct otNetifAddress *mNext;                    ///< A pointer to the next network interface address.
 } otNetifAddress;
 
 /**

src/core/net/ip6.cpp

@@ -993,18 +993,18 @@ const NetifUnicastAddress *Ip6::SelectSourceAddress(MessageInfo &aMessageInfo)
                 rvalIface = candidateId;
                 goto exit;
             }
-            else if (candidateAddr->GetScope() < rvalAddr->GetAddress().GetScope())
+            else if (addr->GetScope() < rvalAddr->GetScope())
             {
                 // Rule 2: Prefer appropriate scope
-                if (candidateAddr->GetScope() >= destination->GetScope())
+                if (addr->GetScope() >= destination->GetScope())
                 {
                     rvalAddr = addr;
                     rvalIface = candidateId;
                 }
             }
-            else if (candidateAddr->GetScope() > rvalAddr->GetAddress().GetScope())
+            else if (addr->GetScope() > rvalAddr->GetScope())
             {
-                if (rvalAddr->GetAddress().GetScope() < destination->GetScope())
+                if (rvalAddr->GetScope() < destination->GetScope())
                 {
                     rvalAddr = addr;
                     rvalIface = candidateId;

src/core/net/netif.hpp

@@ -100,6 +100,16 @@ public:
      */
     Address &GetAddress(void) { return *static_cast<Address *>(&mAddress); }
 
+    /**
+     * This method returns the IPv6 scope value.
+     *
+     * @returns The IPv6 scope value.
+     *
+     */
+    uint8_t GetScope(void) const {
+        return mScopeOverrideValid ? static_cast<uint8_t>(mScopeOverride) : GetAddress().GetScope();
+    }
+
     /**
      * This method returns the next unicast address assigned to the interface.
      *

src/core/thread/mle.cpp

@@ -105,12 +105,16 @@ Mle::Mle(ThreadNetif &aThreadNetif) :
     mLeaderAloc.mPrefixLength = 128;
     mLeaderAloc.mPreferredLifetime = 0xffffffff;
     mLeaderAloc.mValidLifetime = 0xffffffff;
+    mLeaderAloc.mScopeOverride = Ip6::Address::kRealmLocalScope;
+    mLeaderAloc.mScopeOverrideValid = true;
 
     // initialize Mesh Local Prefix
     mMeshLocal64.GetAddress().mFields.m8[0] = 0xfd;
     memcpy(mMeshLocal64.GetAddress().mFields.m8 + 1, mMac.GetExtendedPanId(), 5);
     mMeshLocal64.GetAddress().mFields.m8[6] = 0x00;
     mMeshLocal64.GetAddress().mFields.m8[7] = 0x00;
+    mMeshLocal64.mScopeOverride = Ip6::Address::kRealmLocalScope;
+    mMeshLocal64.mScopeOverrideValid = true;
 
     // mesh-local 64
     for (int i = 8; i < 16; i++)
@@ -130,6 +134,8 @@ Mle::Mle(ThreadNetif &aThreadNetif) :
     mMeshLocal16.mPrefixLength = 64;
     mMeshLocal16.mPreferredLifetime = 0xffffffff;
     mMeshLocal16.mValidLifetime = 0xffffffff;
+    mMeshLocal16.mScopeOverride = Ip6::Address::kRealmLocalScope;
+    mMeshLocal16.mScopeOverrideValid = true;
 
     // Store RLOC address reference in MPL module.
     mNetif.GetIp6().mMpl.SetMatchingAddress(mMeshLocal16.GetAddress());