1 files changed, 8 insertions, 11 deletions
diff --git a/NetworkPkg/Ip6Dxe/Ip6Nd.c b/NetworkPkg/Ip6Dxe/Ip6Nd.c
index 9f30f9b20e..2c8be42f09 100644
--- a/NetworkPkg/Ip6Dxe/Ip6Nd.c
+++ b/NetworkPkg/Ip6Dxe/Ip6Nd.c
@@ -982,6 +982,13 @@ Ip6InitDADProcess (
   NET_CHECK_SIGNATURE (IpIf, IP6_INTERFACE_SIGNATURE);
   ASSERT (AddressInfo != NULL);
 
+  //
+  // Do nothing if we have already started DAD on the address.
+  //
+  if (Ip6FindDADEntry (IpIf->Service, &AddressInfo->Address, NULL) != NULL) {
+    return EFI_SUCCESS;
+  }
+  
   Status   = EFI_SUCCESS;
   IpSb     = IpIf->Service;
   DadXmits = &IpSb->Ip6ConfigInstance.DadXmits;
@@ -1577,16 +1584,6 @@ Ip6ProcessNeighborSolicit (
   if (IsDAD && !IsMaintained) {
     DupAddrDetect = Ip6FindDADEntry (IpSb, &Target, &IpIf);
     if (DupAddrDetect != NULL) {
-      if (DupAddrDetect->Transmit == 0) {
-        //
-        // The NS is from another node to performing DAD on the same address since
-        // we haven't send out any NS yet. Fail DAD for the tentative address.
-        //
-        Ip6OnDADFinished (FALSE, IpIf, DupAddrDetect);
-        Status = EFI_ICMP_ERROR;
-        goto Exit;
-      }
-
       //
       // Check the MAC address of the incoming packet.
       //
@@ -2863,7 +2860,7 @@ Ip6NdFasterTimerTicking (
           //
           Flag = FALSE;
           if ((DupAddrDetect->Receive == 0) ||
-              (DupAddrDetect->Transmit == DupAddrDetect->Receive)) {
+              (DupAddrDetect->Transmit <= DupAddrDetect->Receive)) {
             Flag = TRUE;
           }