[icmp] add OT_ICMP6_ECHO_HANDLER_RLOC_ALOC_ONLY to otIcmp6EchoMode (#10014)

When an icmp echo request is sent to rloc/aloc address of a Thread
device, OT replies to the packet. The packet is also passed to host
and the kernel may reply to the echo request. This would cause 2 echo
replies and may be confusing when testing packet loss rate by pinging
a rloc/aloc address.

Added OT_ICMP6_ECHO_HANDLER_RLOC_ALOC_ONLY to otIcmp6EchoMode to let
OT only handle echo request to rloc/aloc addresses, this is the
default mode in posix code. Set otIcmp6EchoMode to
OT_ICMP6_ECHO_HANDLER_DISABLED will help to avoid double ping replies
from both OT and host.

include/openthread/icmp6.h

@@ -144,6 +144,7 @@ typedef enum otIcmp6EchoMode
     OT_ICMP6_ECHO_HANDLER_UNICAST_ONLY   = 1, ///< ICMPv6 Echo processing enabled only for unicast requests only
     OT_ICMP6_ECHO_HANDLER_MULTICAST_ONLY = 2, ///< ICMPv6 Echo processing enabled only for multicast requests only
     OT_ICMP6_ECHO_HANDLER_ALL            = 3, ///< ICMPv6 Echo processing enabled for unicast and multicast requests
+    OT_ICMP6_ECHO_HANDLER_RLOC_ALOC_ONLY = 4, ///< ICMPv6 Echo processing enabled for RLOC/ALOC destinations only
 } otIcmp6EchoMode;
 
 /**

include/openthread/instance.h

@@ -53,7 +53,7 @@ extern "C" {
  * @note This number versions both OpenThread platform and user APIs.
  *
  */
-#define OPENTHREAD_API_VERSION (404)
+#define OPENTHREAD_API_VERSION (405)
 
 /**
  * @addtogroup api-instance

src/core/net/icmp6.cpp

@@ -171,6 +171,9 @@ bool Icmp::ShouldHandleEchoRequest(const MessageInfo &aMessageInfo)
     case OT_ICMP6_ECHO_HANDLER_ALL:
         rval = true;
         break;
+    case OT_ICMP6_ECHO_HANDLER_RLOC_ALOC_ONLY:
+        rval = aMessageInfo.GetSockAddr().GetIid().IsLocator();
+        break;
     }
 
     return rval;
@@ -184,8 +187,7 @@ Error Icmp::HandleEchoRequest(Message &aRequestMessage, const MessageInfo &aMess
     MessageInfo replyMessageInfo;
     uint16_t    dataOffset;
 
-    // always handle Echo Request destined for RLOC or ALOC
-    VerifyOrExit(ShouldHandleEchoRequest(aMessageInfo) || aMessageInfo.GetSockAddr().GetIid().IsLocator());
+    VerifyOrExit(ShouldHandleEchoRequest(aMessageInfo));
 
     LogInfo("Received Echo Request");
 

src/lib/spinel/spinel.h

@@ -607,6 +607,7 @@ typedef enum
     SPINEL_IPV6_ICMP_PING_OFFLOAD_UNICAST_ONLY   = 1,
     SPINEL_IPV6_ICMP_PING_OFFLOAD_MULTICAST_ONLY = 2,
     SPINEL_IPV6_ICMP_PING_OFFLOAD_ALL            = 3,
+    SPINEL_IPV6_ICMP_PING_OFFLOAD_RLOC_ALOC_ONLY = 4,
 } spinel_ipv6_icmp_ping_offload_mode_t;
 
 typedef enum
@@ -3457,6 +3458,7 @@ enum
      *   SPINEL_IPV6_ICMP_PING_OFFLOAD_UNICAST_ONLY   = 1
      *   SPINEL_IPV6_ICMP_PING_OFFLOAD_MULTICAST_ONLY = 2
      *   SPINEL_IPV6_ICMP_PING_OFFLOAD_ALL            = 3
+     *   SPINEL_IPV6_ICMP_PING_OFFLOAD_RLOC_ALOC_ONLY = 4
      *
      * Default value is `NET_IPV6_ICMP_PING_OFFLOAD_DISABLED`.
      *

src/ncp/ncp_base.cpp

@@ -340,7 +340,7 @@ NcpBase::NcpBase(Instance *aInstance)
 #if OPENTHREAD_CONFIG_UDP_FORWARD_ENABLE
     otUdpForwardSetForwarder(mInstance, &NcpBase::HandleUdpForwardStream, this);
 #endif
-    otIcmp6SetEchoMode(mInstance, OT_ICMP6_ECHO_HANDLER_DISABLED);
+    otIcmp6SetEchoMode(mInstance, OT_ICMP6_ECHO_HANDLER_RLOC_ALOC_ONLY);
 #if OPENTHREAD_FTD
     otThreadRegisterNeighborTableCallback(mInstance, &NcpBase::HandleNeighborTableChanged);
 #if OPENTHREAD_CONFIG_MLE_STEERING_DATA_SET_OOB_ENABLE

src/ncp/ncp_base_mtd.cpp

@@ -2072,6 +2072,9 @@ template <> otError NcpBase::HandlePropertyGet<SPINEL_PROP_IPV6_ICMP_PING_OFFLOA
     case OT_ICMP6_ECHO_HANDLER_ALL:
         mode = SPINEL_IPV6_ICMP_PING_OFFLOAD_ALL;
         break;
+    case OT_ICMP6_ECHO_HANDLER_RLOC_ALOC_ONLY:
+        mode = SPINEL_IPV6_ICMP_PING_OFFLOAD_RLOC_ALOC_ONLY;
+        break;
     };
 
     return mEncoder.WriteUint8(mode);
@@ -2099,6 +2102,9 @@ template <> otError NcpBase::HandlePropertySet<SPINEL_PROP_IPV6_ICMP_PING_OFFLOA
     case SPINEL_IPV6_ICMP_PING_OFFLOAD_ALL:
         mode = OT_ICMP6_ECHO_HANDLER_ALL;
         break;
+    case SPINEL_IPV6_ICMP_PING_OFFLOAD_RLOC_ALOC_ONLY:
+        mode = OT_ICMP6_ECHO_HANDLER_RLOC_ALOC_ONLY;
+        break;
     };
 
     otIcmp6SetEchoMode(mInstance, mode);