From 0071edcf7a787a9e70f5bc9d6ddcc7274d82f90b Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@nestlabs.com>
Date: Fri, 16 Sep 2016 17:27:52 -0700
Subject: [PATCH] Pass up datagrams that are routed to this device but have no
 further route. (#617)

---
 src/core/net/ip6.cpp             | 38 ++++++++++++++++++++++++--------
 src/core/net/ip6.hpp             |  4 ++--
 src/core/thread/thread_netif.cpp | 13 ++++++++++-
 3 files changed, 43 insertions(+), 12 deletions(-)

diff --git a/src/core/net/ip6.cpp b/src/core/net/ip6.cpp
index 7381738ad..b08788486 100644
--- a/src/core/net/ip6.cpp
+++ b/src/core/net/ip6.cpp
@@ -347,18 +347,19 @@ exit:
     return error;
 }
 
-void Ip6::ProcessReceiveCallback(const Message &aMessage, const MessageInfo &messageInfo, uint8_t aIpProto)
+ThreadError Ip6::ProcessReceiveCallback(const Message &aMessage, const MessageInfo &messageInfo, uint8_t aIpProto)
 {
     ThreadError error = kThreadError_None;
     Message *messageCopy = NULL;
 
-    VerifyOrExit(mReceiveIp6DatagramCallback != NULL, ;);
+    VerifyOrExit(mReceiveIp6DatagramCallback != NULL, error = kThreadError_NoRoute);
 
     if (mIsReceiveIp6FilterEnabled)
     {
         // do not pass messages sent to/from an RLOC
         VerifyOrExit(!messageInfo.GetSockAddr().IsRoutingLocator() &&
-                     !messageInfo.GetPeerAddr().IsRoutingLocator(), ;);
+                     !messageInfo.GetPeerAddr().IsRoutingLocator(),
+                     error = kThreadError_NoRoute);
 
         switch (aIpProto)
         {
@@ -369,7 +370,7 @@ void Ip6::ProcessReceiveCallback(const Message &aMessage, const MessageInfo &mes
                 aMessage.Read(aMessage.GetOffset(), sizeof(icmp), &icmp);
 
                 // do not pass ICMP Echo Request messages
-                VerifyOrExit(icmp.GetType() != IcmpHeader::kTypeEchoRequest, ;);
+                VerifyOrExit(icmp.GetType() != IcmpHeader::kTypeEchoRequest, error = kThreadError_NoRoute);
             }
 
             break;
@@ -381,7 +382,7 @@ void Ip6::ProcessReceiveCallback(const Message &aMessage, const MessageInfo &mes
                 aMessage.Read(aMessage.GetOffset(), sizeof(udp), &udp);
 
                 // do not pass MLE messages
-                VerifyOrExit(udp.GetDestinationPort() != Mle::kUdpPort, ;);
+                VerifyOrExit(udp.GetDestinationPort() != Mle::kUdpPort, error = kThreadError_NoRoute);
             }
 
             break;
@@ -405,6 +406,8 @@ exit:
     {
         messageCopy->Free();
     }
+
+    return error;
 }
 
 ThreadError Ip6::HandleDatagram(Message &message, Netif *netif, int8_t interfaceId, const void *linkMessageInfo,
@@ -515,7 +518,7 @@ ThreadError Ip6::HandleDatagram(Message &message, Netif *netif, int8_t interface
         {
             hopLimit = header.GetHopLimit();
             message.Write(Header::GetHopLimitOffset(), Header::GetHopLimitSize(), &hopLimit);
-            SuccessOrExit(error = ForwardMessage(message, messageInfo));
+            SuccessOrExit(error = ForwardMessage(message, messageInfo, nextHeader));
         }
     }
 
@@ -529,7 +532,7 @@ exit:
     return error;
 }
 
-ThreadError Ip6::ForwardMessage(Message &message, MessageInfo &messageInfo)
+ThreadError Ip6::ForwardMessage(Message &message, MessageInfo &messageInfo, uint8_t ipproto)
 {
     ThreadError error = kThreadError_None;
     int8_t interfaceId;
@@ -557,8 +560,25 @@ ThreadError Ip6::ForwardMessage(Message &message, MessageInfo &messageInfo)
     }
     else
     {
-        otDumpDebgIp6("no route", &messageInfo.GetSockAddr(), 16);
-        ExitNow(error = kThreadError_NoRoute);
+        // try passing to host
+        error = ProcessReceiveCallback(message, messageInfo, ipproto);
+
+        switch (error)
+        {
+        case kThreadError_None:
+            // the caller transfers custody in the success case, so free the message here
+            message.Free();
+            break;
+
+        case kThreadError_NoRoute:
+            otDumpDebgIp6("no route", &messageInfo.GetSockAddr(), 16);
+            break;
+
+        default:
+            break;
+        }
+
+        ExitNow();
     }
 
     // submit message to interface
diff --git a/src/core/net/ip6.hpp b/src/core/net/ip6.hpp
index fb3b4c8ab..e64788b7a 100644
--- a/src/core/net/ip6.hpp
+++ b/src/core/net/ip6.hpp
@@ -335,13 +335,13 @@ private:
     static void HandleSendQueue(void *aContext);
     void HandleSendQueue(void);
 
-    void ProcessReceiveCallback(const Message &aMessage, const MessageInfo &aMessageInfo, uint8_t aIpProto);
+    ThreadError ProcessReceiveCallback(const Message &aMessage, const MessageInfo &aMessageInfo, uint8_t aIpProto);
     ThreadError HandleExtensionHeaders(Message &message, uint8_t &nextHeader, bool receive);
     ThreadError HandleFragment(Message &message);
     ThreadError AddMplOption(Message &message, Header &header, IpProto nextHeader, uint16_t payloadLength);
     ThreadError HandleOptions(Message &message);
     ThreadError HandlePayload(Message &message, MessageInfo &messageInfo, uint8_t ipproto);
-    ThreadError ForwardMessage(Message &message, MessageInfo &messageInfo);
+    ThreadError ForwardMessage(Message &message, MessageInfo &messageInfo, uint8_t ipproto);
 
     Mpl mMpl;
     bool mForwardingEnabled;
diff --git a/src/core/thread/thread_netif.cpp b/src/core/thread/thread_netif.cpp
index d597eac72..42dd9ef3d 100644
--- a/src/core/thread/thread_netif.cpp
+++ b/src/core/thread/thread_netif.cpp
@@ -130,7 +130,18 @@ ThreadError ThreadNetif::GetLinkAddress(Ip6::LinkAddress &address) const
 
 ThreadError ThreadNetif::RouteLookup(const Ip6::Address &source, const Ip6::Address &destination, uint8_t *prefixMatch)
 {
-    return mNetworkDataLeader.RouteLookup(source, destination, prefixMatch, NULL);
+    ThreadError error;
+    uint16_t rloc;
+
+    SuccessOrExit(error = mNetworkDataLeader.RouteLookup(source, destination, prefixMatch, &rloc));
+
+    if (rloc == mMleRouter.GetRloc16())
+    {
+        error = kThreadError_NoRoute;
+    }
+
+exit:
+    return error;
 }
 
 ThreadError ThreadNetif::SendMessage(Message &message)