add util for get port from base and diff

internal/configs/node/config.go

@@ -69,6 +69,8 @@ type ConfigType struct {
 	isBeacon bool        // whether this node is beacon node doing consensus or not
 	ShardID  uint32      // ShardID of this node
 	role     Role        // Role of the node
+	Port     string
+	IP       string
 
 	StringRole      string
 	Host            p2p.Host

internal/utils/utils.go

@@ -15,8 +15,8 @@ import (
 	"sync"
 
 	"github.com/ethereum/go-ethereum/common"
-
 	"github.com/harmony-one/bls/ffi/go/bls"
+	"github.com/harmony-one/harmony/internal/utils"
 	p2p_crypto "github.com/libp2p/go-libp2p-crypto"
 )
 
@@ -233,3 +233,12 @@ func GetBlsAddress(key *bls.PublicKey) common.Address {
 	addr.SetBytes(addrBytes[:])
 	return addr
 }
+
+// GetPortFromDiff returns the port from base and the diff.
+func GetPortFromDiff(port string, diff int) string {
+	if portNum, err := strconv.Atoi(port); err == nil {
+		return fmt.Sprintf("%d", portNum-diff)
+	}
+	utils.GetLogInstance().Error("error on parsing port.")
+	return ""
+}