Caplin: added IPV6 support

cl/phase1/forkchoice/fork_graph/fork_graph_disk.go

@@ -170,6 +170,9 @@ func (f *forkGraphDisk) AnchorSlot() uint64 {
 }
 
 func (f *forkGraphDisk) isBlockRootTheCurrentState(blockRoot libcommon.Hash) bool {
+	if f.currentState == nil {
+		return false
+	}
 	blockRootState, _ := f.currentState.BlockRoot()
 	return blockRoot == blockRootState
 }
@@ -199,7 +202,7 @@ func (f *forkGraphDisk) AddChainSegment(signedBlock *cltypes.SignedBeaconBlock,
 	} else {
 		newState, err = f.getState(block.ParentRoot, false, true)
 		if err != nil {
-			return nil, LogisticError, fmt.Errorf("AddChainSegment: %w, parentRoot; %x", err, block.ParentRoot)
+			return nil, LogisticError, fmt.Errorf("AddChainSegment: %w, parentRoot: %x", err, block.ParentRoot)
 		}
 	}
 
@@ -262,7 +265,7 @@ func (f *forkGraphDisk) AddChainSegment(signedBlock *cltypes.SignedBeaconBlock,
 			// Add block to list of invalid blocks
 			log.Warn("Invalid beacon block", "slot", block.Slot, "blockRoot", blockRoot, "reason", invalidBlockErr)
 			f.badBlocks.Store(libcommon.Hash(blockRoot), struct{}{})
-			//f.currentState = nil
+			f.currentState = nil
 
 			return nil, InvalidBlock, invalidBlockErr
 		}

cl/sentinel/sentinel.go

@@ -147,25 +147,20 @@ func (s *Sentinel) createListener() (*discover.UDPv5, error) {
 	)
 
 	ip := net.ParseIP(ipAddr)
-	if ip.To4() == nil {
-		return nil, fmt.Errorf("IPV4 address not provided instead %s was provided", ipAddr)
+	if ip == nil {
+		return nil, fmt.Errorf("bad ip address provided, %s was provided", ipAddr)
 	}
 
 	var bindIP net.IP
 	var networkVersion string
 
-	// check for our network version
-	switch {
-	// if we have 16 byte and 4 byte representation then we are in using udp6
-	case ip.To16() != nil && ip.To4() == nil:
-		bindIP = net.IPv6zero
-		networkVersion = "udp6"
-		// only 4 bytes then we are using udp4
-	case ip.To4() != nil:
+	// If the IP is an IPv4 address, bind to the correct zero address.
+	if ip.To4() != nil {
 		bindIP = net.IPv4zero
 		networkVersion = "udp4"
-	default:
-		return nil, fmt.Errorf("bad ip address provided, %s was provided", ipAddr)
+	} else {
+		bindIP = net.IPv6zero
+		networkVersion = "udp6"
 	}
 
 	udpAddr := &net.UDPAddr{