feat(portscan): add CIDR prefix support and base IP handling

Add CIDR prefix option to define IP range for scanning, with default base IP of
10.0.1.0 and prefix 24. Update methods to retrieve base IP and prefix
separately.

src/cli/portscan_cli.cpp

@@ -4,7 +4,6 @@
 
 PortScanCli::PortScanCli()
     : CliBase("Port Scanner Options")
-    , ip_("")
 {
 }
 
@@ -13,14 +12,17 @@ void PortScanCli::setupOptions()
     // clang-format off
     desc_.add_options()
         ("help,h",      "Show help")
-        ("ip,H",       withDefault(ip_, "<IP>"),    "Local IPv4 to scan");
+        ("ip,H",        withDefault(ip_, "<IPv4>"),      "Base IPv4 inside your LAN (e.g. 10.0.1.42)")
+        ("prefix,p",    withDefault(prefix_, "<0..32>"), "CIDR prefix length (e.g. 24)");
     // clang-format on
 }
 
-std::string PortScanCli::getIp() const
+int PortScanCli::getPrefix() const
 {
-    if (vm_["ip"].empty() == 0) {
-        return "127.0.0.1";
+    return vm_.at("prefix").as<int>();
 }
+
+std::string PortScanCli::getBaseIp() const
+{
     return vm_.at("ip").as<std::string>();
 }

src/cli/portscan_cli.hpp

@@ -9,11 +9,13 @@ class PortScanCli : public CliBase, protected OptionUtils
   public:
     PortScanCli();
 
-    std::string getIp() const;
+    int getPrefix() const;
+    std::string getBaseIp() const;
 
   protected:
     void setupOptions() override;
 
   private:
-    std::string ip_;
+    int prefix_{24};
+    std::string ip_{"10.0.1.0"};
 };