[libasiotap/libfreelan] Adds an option to set DHCP for interface (Win…

…dows only).

apps/freelan/config/freelan.cfg

@@ -465,6 +465,14 @@ public_endpoint=0.0.0.0
 #
 ipv4_address_prefix_length=9.0.0.1/24
 
+# The tap adapter interface DHCP status.
+#
+# If it is on the interface will send DHCP request to obtain IPv4 address from
+# DHCP server (which must be installed on the FreeLAN overlay network).
+#
+# Note: this is only available for Windows!
+ipv4_dhcp=false
+
 # The tap adapter IPv6 address and prefix length to use.
 #
 # The network address must be in numeric format with a netmask suffix.

apps/freelan/src/configuration_helper.cpp

@@ -335,6 +335,7 @@ po::options_description get_tap_adapter_options()
 	("tap_adapter.mss_override", po::value<fl::mss_type>()->default_value(fl::mss_type()), "The MSS override.")
 	("tap_adapter.metric", po::value<fl::metric_type>()->default_value(fl::auto_metric_type()), "The metric of the tap adapter.")
 	("tap_adapter.ipv4_address_prefix_length", po::value<asiotap::ipv4_network_address>(), "The tap adapter IPv4 address and prefix length.")
+	("tap_adapter.ipv4_dhcp", po::value<bool>()->default_value(false), "The tap adapter IPv4 DHCP status.")
 	("tap_adapter.ipv6_address_prefix_length", po::value<asiotap::ipv6_network_address>(), "The tap adapter IPv6 address and prefix length.")
 	("tap_adapter.remote_ipv4_address", po::value<asiotap::ipv4_network_address>(), "The tap adapter IPv4 remote address.")
 	("tap_adapter.arp_proxy_enabled", po::value<bool>()->default_value(false), "Whether to enable the ARP proxy.")
@@ -538,6 +539,11 @@ void setup_configuration(const fscp::logger& logger, fl::configuration& configur
 		configuration.tap_adapter.ipv4_address_prefix_length = vm["tap_adapter.ipv4_address_prefix_length"].as<asiotap::ipv4_network_address>();
 	}
 
+	if (vm.count("tap_adapter.ipv4_dhcp"))
+	{
+		configuration.tap_adapter.ipv4_dhcp = vm["tap_adapter.ipv4_dhcp"].as<bool>();
+	}
+
 	if (vm.count("tap_adapter.ipv6_address_prefix_length"))
 	{
 		configuration.tap_adapter.ipv6_address_prefix_length = vm["tap_adapter.ipv6_address_prefix_length"].as<asiotap::ipv6_network_address>();

libs/asiotap/include/asiotap/tap_adapter_configuration.hpp

@@ -58,6 +58,7 @@ namespace asiotap
 		{
 			boost::optional<ipv4_network_address> network_address;
 			boost::optional<boost::asio::ip::address_v4> remote_address;
+			bool dhcp;
 		};
 
 		struct ipv6_configuration

libs/asiotap/include/asiotap/windows/windows_route_manager.hpp

@@ -84,6 +84,7 @@ namespace asiotap
 			{
 			}
 
+			void netsh_interface_ip_set_dhcp(const std::string& interface_name, bool persistent = false);
 			void netsh_interface_ip_set_address(const std::string& interface_name, const ip_network_address& address, bool persistent = false);
 
 			windows_route_manager::route_type get_route_for(const boost::asio::ip::address& host);

libs/asiotap/src/windows/windows_route_manager.cpp

@@ -170,6 +170,32 @@ namespace asiotap
 		unregister_route(route_entry.interface, route_entry.route, route_entry.metric);
 	}
 
+	void windows_route_manager::netsh_interface_ip_set_dhcp(const std::string& interface_name, bool persistent)
+	{
+		std::vector<std::string> args {
+			"interface",
+			"ip",
+			"set",
+			"address",
+			"dhcp",
+			"name=" + interface_name,
+			persistent ? "store=persistent" : "store=active"
+		};
+
+#ifdef UNICODE
+		std::vector<std::wstring> wargs;
+
+		for (auto&& arg : args)
+		{
+			wargs.push_back(multi_byte_to_wide_char(arg));
+		}
+
+		netsh(wargs);
+#else
+		netsh(args);
+#endif
+	}
+
 	void windows_route_manager::netsh_interface_ip_set_address(const std::string& interface_name, const ip_network_address& address, bool persistent)
 	{
 		std::vector<std::string> args;

libs/asiotap/src/windows/windows_tap_adapter.cpp

@@ -335,8 +335,8 @@ namespace asiotap
 		DWORD len;
 
 		if (!::DeviceIoControl(descriptor().native_handle(), TAP_WIN_IOCTL_SET_MEDIA_STATUS,
-                             &status, sizeof(status),
-                             &status, sizeof(status), &len, NULL))
+					&status, sizeof(status),
+					&status, sizeof(status), &len, NULL))
 		{
 			throw boost::system::system_error(::GetLastError(), boost::system::system_category());
 		}
@@ -488,6 +488,21 @@ namespace asiotap
 			}
 		}
 
+		if (configuration.ipv4.dhcp)
+		{
+			try
+			{
+				m_route_manager.netsh_interface_ip_set_dhcp(display_name());
+			}
+			catch (const boost::system::system_error& ex)
+			{
+				if (ex.code() != executeplus::executeplus_error::external_process_failed)
+				{
+					throw;
+				}
+			}
+		}
+
 		if (configuration.ipv6.network_address)
 		{
 			try

libs/freelan/include/freelan/configuration.hpp

@@ -467,6 +467,11 @@ namespace freelan
 		 */
 		asiotap::ipv4_network_address ipv4_address_prefix_length;
 
+		/**
+		 * \brief The IPv4 tap adapter DHCP status.
+		 */
+		bool ipv4_dhcp;
+
 		/**
 		 * \brief The IPv6 tap adapter address.
 		 */

libs/freelan/src/core.cpp

@@ -1787,6 +1787,9 @@ namespace freelan
 				m_logger(fscp::log_level::information) << "No IPv4 address configured.";
 			}
 
+			// IPv4 DHCP (for Windows)
+			tap_config.ipv4.dhcp = m_configuration.tap_adapter.ipv4_dhcp;
+
 			// IPv6 address
 			if (!m_configuration.tap_adapter.ipv6_address_prefix_length.is_null())
 			{