add domain whois/dns support, refactor codebase

internal/common/utils.go

@@ -0,0 +1,25 @@
+package common
+
+import (
+	"net"
+
+	"ipinfo/utils"
+)
+
+// ToPtr converts a string to a pointer, returning nil for empty strings.
+func ToPtr(s string) *string {
+	if s == "" {
+		return nil
+	}
+	return &s
+}
+
+// IsBogon checks if the IP is a bogon IP.
+func IsBogon(ip net.IP) bool {
+	for _, network := range utils.BogonNets {
+		if network.Contains(ip) {
+			return true
+		}
+	}
+	return false
+}