From a43fb455d99d3692bdc68aa6d9be96f973a1a4ea Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@nestlabs.com>
Date: Fri, 24 Jun 2016 12:43:02 -0700
Subject: [PATCH] Add ability to configure whether or not OpenThread handles
 ICMPv6 Echo Request/Reply messages. (#207)

---
 include/openthread.h    | 17 +++++++++++++++++
 src/core/net/icmp6.cpp  | 22 ++++++++++++++++++----
 src/core/net/icmp6.hpp  | 19 +++++++++++++++++++
 src/core/openthread.cpp | 11 +++++++++++
 src/ncp/ncp_base.cpp    |  1 +
 5 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/include/openthread.h b/include/openthread.h
index b0f0413d5..3bf9789fb 100644
--- a/include/openthread.h
+++ b/include/openthread.h
@@ -1194,6 +1194,23 @@ void otSetReceiveIp6DatagramCallback(otReceiveIp6DatagramCallback aCallback);
  */
 ThreadError otSendIp6Datagram(otMessage aMessage);
 
+/**
+ * This function indicates whether or not ICMPv6 Echo processing is enabled.
+ *
+ * @retval TRUE   ICMPv6 Echo processing is enabled.
+ * @retval FALSE  ICMPv6 Echo processing is disabled.
+ *
+ */
+bool otIsIcmpEchoEnabled(void);
+
+/**
+ * This function sets whether or not ICMPv6 Echo processing is enabled.
+ *
+ * @param[in]  aEnabled  TRUE to enable ICMPv6 Echo processing, FALSE otherwise.
+ *
+ */
+void otSetIcmpEchoEnabled(bool aEnabled);
+
 /**
  * @}
  *
diff --git a/src/core/net/icmp6.cpp b/src/core/net/icmp6.cpp
index 695859813..b9401aed2 100644
--- a/src/core/net/icmp6.cpp
+++ b/src/core/net/icmp6.cpp
@@ -45,6 +45,8 @@ using Thread::Encoding::BigEndian::HostSwap16;
 namespace Thread {
 namespace Ip6 {
 
+bool Icmp::sIsEchoEnabled = true;
+
 uint16_t IcmpEcho::sNextId = 1;
 IcmpEcho *IcmpEcho::sEchoClients = NULL;
 IcmpHandler *IcmpHandler::sHandlers = NULL;
@@ -205,7 +207,7 @@ ThreadError Icmp::HandleEchoRequest(Message &aRequestMessage, const MessageInfo
     MessageInfo replyMessageInfo;
     uint16_t payloadLength;
 
-    payloadLength = aRequestMessage.GetLength() - aRequestMessage.GetOffset() - IcmpHeader::GetDataOffset();
+    VerifyOrExit(sIsEchoEnabled, ;);
 
     otLogInfoIcmp("Received Echo Request\n");
 
@@ -213,6 +215,7 @@ ThreadError Icmp::HandleEchoRequest(Message &aRequestMessage, const MessageInfo
     icmp6Header.SetType(IcmpHeader::kTypeEchoReply);
 
     VerifyOrExit((replyMessage = Ip6::NewMessage(0)) != NULL, otLogDebgIcmp("icmp fail\n"));
+    payloadLength = aRequestMessage.GetLength() - aRequestMessage.GetOffset() - IcmpHeader::GetDataOffset();
     SuccessOrExit(replyMessage->SetLength(IcmpHeader::GetDataOffset() + payloadLength));
 
     replyMessage->Write(0, IcmpHeader::GetDataOffset(), &icmp6Header);
@@ -244,18 +247,19 @@ exit:
 }
 
 ThreadError Icmp::HandleEchoReply(Message &aMessage, const MessageInfo &aMessageInfo,
-                                  const IcmpHeader &aIcmpheader)
+                                  const IcmpHeader &aIcmpHeader)
 {
-    uint16_t id = aIcmpheader.GetId();
+    VerifyOrExit(sIsEchoEnabled, ;);
 
     for (IcmpEcho *client = IcmpEcho::sEchoClients; client; client = client->mNext)
     {
-        if (client->mId == id)
+        if (client->mId == aIcmpHeader.GetId())
         {
             client->HandleEchoReply(aMessage, aMessageInfo);
         }
     }
 
+exit:
     return kThreadError_None;
 }
 
@@ -274,5 +278,15 @@ ThreadError Icmp::UpdateChecksum(Message &aMessage, uint16_t aChecksum)
     return kThreadError_None;
 }
 
+bool Icmp::IsEchoEnabled(void)
+{
+    return sIsEchoEnabled;
+}
+
+void Icmp::SetEchoEnabled(bool aEnabled)
+{
+    sIsEchoEnabled = aEnabled;
+}
+
 }  // namespace Ip6
 }  // namespace Thread
diff --git a/src/core/net/icmp6.hpp b/src/core/net/icmp6.hpp
index 8951e8c21..954075903 100644
--- a/src/core/net/icmp6.hpp
+++ b/src/core/net/icmp6.hpp
@@ -367,12 +367,31 @@ public:
      */
     static ThreadError UpdateChecksum(Message &aMessage, uint16_t aPseudoHeaderChecksum);
 
+    /**
+     * This static method indicates whether or not ICMPv6 Echo processing is enabled.
+     *
+     * @retval TRUE   ICMPv6 Echo processing is enabled.
+     * @retval FALSE  ICMPv6 Echo processing is disabled.
+     *
+     */
+    static bool IsEchoEnabled(void);
+
+    /**
+     * This static method sets whether or not ICMPv6 Echo processing is enabled.
+     *
+     * @param[in]  aEnabled  TRUE to enable ICMPv6 Echo processing, FALSE otherwise.
+     *
+     */
+    static void SetEchoEnabled(bool aEnabled);
+
 private:
     static ThreadError HandleDstUnreach(Message &aMessage, const MessageInfo &aMessageInfo,
                                         const IcmpHeader &aIcmpHeader);
     static ThreadError HandleEchoRequest(Message &aMessage, const MessageInfo &aMessageInfo);
     static ThreadError HandleEchoReply(Message &aMessage, const MessageInfo &aMessageInfo,
                                        const IcmpHeader &aIcmpHeader);
+
+    static bool sIsEchoEnabled;
 };
 
 /**
diff --git a/src/core/openthread.cpp b/src/core/openthread.cpp
index 8205d044e..05ba554df 100644
--- a/src/core/openthread.cpp
+++ b/src/core/openthread.cpp
@@ -39,6 +39,7 @@
 #include <common/new.hpp>
 #include <common/tasklet.hpp>
 #include <common/timer.hpp>
+#include <net/icmp6.hpp>
 #include <platform/random.h>
 #include <thread/thread_netif.hpp>
 
@@ -735,6 +736,16 @@ ThreadError otSendUdp(otUdpSocket *aSocket, otMessage aMessage, const otMessageI
                           *reinterpret_cast<const Ip6::MessageInfo *>(aMessageInfo));
 }
 
+bool otIsIcmpEchoEnabled(void)
+{
+    return Ip6::Icmp::IsEchoEnabled();
+}
+
+void otSetIcmpEchoEnabled(bool aEnabled)
+{
+    Ip6::Icmp::SetEchoEnabled(aEnabled);
+}
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif
diff --git a/src/ncp/ncp_base.cpp b/src/ncp/ncp_base.cpp
index d370f3a6d..729a829e0 100644
--- a/src/ncp/ncp_base.cpp
+++ b/src/ncp/ncp_base.cpp
@@ -239,6 +239,7 @@ NcpBase::NcpBase():
     assert(sThreadNetif != NULL);
     otSetStateChangedCallback(&HandleNetifStateChanged, this);
     otSetReceiveIp6DatagramCallback(&HandleDatagramFromStack);
+    otSetIcmpEchoEnabled(false);
 }
 
 // ----------------------------------------------------------------------------