lxip: support configuration of libc plugin

Added support for the 'ip_addr', 'gateway', and 'netmask' configuration
parameter.

Issue #984

dde_linux/include/lxip/lxip.h

@@ -31,7 +31,15 @@ namespace Lxip {
 
 	class Socketcall;
 
-	Socketcall & init();
+	/**
+	 * Init backend
+	 *
+	 * \param  address_config  for dynamic configuration use "dhcp", for static
+	 *                         configuration use "<ip>::<gw-ip>:<netmask>:::off"
+	 *
+	 * \return Reference to Socketcall object
+	 */
+	Socketcall & init(char *address_config);
 
 	typedef Genode::uint8_t  uint8_t;
 	typedef Genode::uint16_t uint16_t;

dde_linux/src/lib/libc_lxip/init.cc

@@ -14,11 +14,65 @@
  */
 
 #include <base/printf.h>
+#include <base/snprintf.h>
+#include <os/config.h>
+#include <util/string.h>
 
-extern void create_lxip_plugin();
+extern void create_lxip_plugin(char *address_config);
 
 void __attribute__((constructor)) init_libc_lxip(void)
 {
-	PDBG("init_libc_lxip()\n");
-	create_lxip_plugin();
+	char ip_addr_str[16] = {0};
+	char netmask_str[16] = {0};
+	char gateway_str[16] = {0};
+	char address_buf[128];
+	char *address_config;
+
+	try {
+		Genode::Xml_node libc_node = Genode::config()->xml_node().sub_node("libc");
+
+		try {
+			libc_node.attribute("ip_addr").value(ip_addr_str, sizeof(ip_addr_str));
+		} catch(...) { }
+
+		try {
+			libc_node.attribute("netmask").value(netmask_str, sizeof(netmask_str));
+		} catch(...) { }
+
+		try {
+			libc_node.attribute("gateway").value(gateway_str, sizeof(gateway_str));
+		} catch(...) { }
+
+		/* either none or all 3 interface attributes must exist */
+		if ((Genode::strlen(ip_addr_str) != 0) ||
+		    (Genode::strlen(netmask_str) != 0) ||
+		    (Genode::strlen(gateway_str) != 0)) {
+			if (Genode::strlen(ip_addr_str) == 0) {
+				PERR("Missing \"ip_addr\" attribute. Ignoring network interface config.");
+				throw Genode::Xml_node::Nonexistent_attribute();
+			} else if (Genode::strlen(netmask_str) == 0) {
+				PERR("Missing \"netmask\" attribute. Ignoring network interface config.");
+				throw Genode::Xml_node::Nonexistent_attribute();
+			} else if (Genode::strlen(gateway_str) == 0) {
+				PERR("Missing \"gateway\" attribute. Ignoring network interface config.");
+				throw Genode::Xml_node::Nonexistent_attribute();
+			}
+		} else
+			throw -1;
+
+		PDBG("static network interface: ip_addr=%s netmask=%s gateway=%s ",
+		     ip_addr_str, netmask_str, gateway_str);
+
+		Genode::snprintf(address_buf, sizeof(address_buf), "%s::%s:%s:::off",
+		                 ip_addr_str, gateway_str, netmask_str);
+		address_config = address_buf;
+	}
+	catch (...) {
+		PINF("Using DHCP for interface configuration.");
+		address_config = "dhcp";
+	}
+
+	PDBG("init_libc_lxip() address config=%s\n", address_config);
+
+	create_lxip_plugin(address_config);
 }

dde_linux/src/lib/libc_lxip/plugin.cc

@@ -81,7 +81,7 @@ struct Plugin : Libc::Plugin
 	/**
 	 * Constructor
 	 */
-	Plugin();
+	Plugin(char *address_config);
 
 	bool supports_select(int nfds,
 	                     fd_set *readfds,
@@ -138,7 +138,7 @@ struct Plugin : Libc::Plugin
 };
 
 
-Plugin::Plugin() : socketcall(Lxip::init())
+Plugin::Plugin(char *address_config) : socketcall(Lxip::init(address_config))
 {
 	PDBG("using the lxip libc plugin");
 }
@@ -649,7 +649,7 @@ int Plugin::translate_ops_linux(int optname)
 } /* unnamed namespace */
 
 
-void create_lxip_plugin()
+void create_lxip_plugin(char *address_config)
 {
-	static Plugin lxip_plugin;
+	static Plugin lxip_plugin(address_config);
 }

dde_linux/src/lib/lxip/include/init.h

@@ -16,6 +16,7 @@
 #ifdef __cplusplus
 extern "C"
 #endif
-int lxip_init(void);
+
+int lxip_init(char *address_config);
 
 #endif

dde_linux/src/lib/lxip/init.c

@@ -39,17 +39,16 @@ unsigned long nr_free_buffer_pages(void)
 /**
  * Initialize sub-systems
  */
-int lxip_init()
+int lxip_init(char *address_config)
 {
 	/* init data */
 	INIT_LIST_HEAD(&init_net.dev_base_head);
 
-
 	/*start jiffies */
 	dde_kit_timer_init(0, 0);
 
 	/* call __setup stuff */
-	__ip_auto_config_setup("dhcp");
+	__ip_auto_config_setup(address_config);
 
 	core_sock_init();
 	core_netlink_proto_init();
@@ -70,7 +69,7 @@ int lxip_init()
 	/* late  */
 	late_tcp_congestion_default();
 
-	/* dhcp */
+	/* dhcp or static configuration */
 	late_ip_auto_config();
 
 	return 1;

dde_linux/src/lib/lxip/socket_handler.cc

@@ -621,9 +621,9 @@ class Net::Socketcall : public Genode::Signal_dispatcher_base,
 };
 
 
-Lxip::Socketcall & Lxip::init()
+Lxip::Socketcall & Lxip::init(char *address_config)
 {
-	static int             init = lxip_init();
+	static int             init = lxip_init(address_config);
 	static Net::Socketcall socketcall;
 
 	return socketcall;