From 98cbfa3561e708a3cde46dade0b2c610103b4daa Mon Sep 17 00:00:00 2001
From: Christian Helmuth <christian.helmuth@genode-labs.com>
Date: Thu, 8 Jun 2023 17:38:16 +0200
Subject: [PATCH] genode_c_api: MAC address reporter utility

Issue #4918
---
 .../genode_c_api/mac_address_reporter.h       |  43 ++++++
 .../lib/genode_c_api/mac_address_reporter.cc  | 132 ++++++++++++++++++
 2 files changed, 175 insertions(+)
 create mode 100644 repos/os/include/genode_c_api/mac_address_reporter.h
 create mode 100644 repos/os/src/lib/genode_c_api/mac_address_reporter.cc

diff --git a/repos/os/include/genode_c_api/mac_address_reporter.h b/repos/os/include/genode_c_api/mac_address_reporter.h
new file mode 100644
index 0000000000..592a3dfc4a
--- /dev/null
+++ b/repos/os/include/genode_c_api/mac_address_reporter.h
@@ -0,0 +1,43 @@
+/*
+ * \brief  C-API Genode MAC address reporter utility
+ * \author Christian Helmuth
+ * \date   2023-06-06
+ */
+
+/*
+ * Copyright (C) 2023 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#ifndef _GENODE_C_API__MAC_ADDRESS_REPORTER_H_
+#define _GENODE_C_API__MAC_ADDRESS_REPORTER_H_
+
+#include <genode_c_api/base.h>
+
+
+#ifdef __cplusplus
+
+#include <util/xml_node.h>
+
+void genode_mac_address_reporter_init(Genode::Env &, Genode::Allocator &);
+
+void genode_mac_address_reporter_config(Genode::Xml_node const &);
+
+#endif
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct genode_mac_address { unsigned char addr[6]; };
+
+void genode_mac_address_register(char const * name, struct genode_mac_address addr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _GENODE_C_API__MAC_ADDRESS_REPORTER_H_ */
diff --git a/repos/os/src/lib/genode_c_api/mac_address_reporter.cc b/repos/os/src/lib/genode_c_api/mac_address_reporter.cc
new file mode 100644
index 0000000000..1d500c61a7
--- /dev/null
+++ b/repos/os/src/lib/genode_c_api/mac_address_reporter.cc
@@ -0,0 +1,132 @@
+/*
+ * \brief  C-API Genode MAC address reporter utility
+ * \author Christian Helmuth
+ * \date   2023-06-06
+ */
+
+/*
+ * Copyright (C) 2023 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#include <base/registry.h>
+#include <os/reporter.h>
+#include <net/mac_address.h>
+
+#include <genode_c_api/mac_address_reporter.h>
+
+using namespace Genode;
+
+typedef String<32> Mac_name;
+
+struct Mac_address : Registry<Mac_address>::Element
+{
+	Mac_name         name;
+	Net::Mac_address addr;
+
+	Mac_address(Registry<Mac_address > &registry,
+	            Mac_name         const &name,
+	            Net::Mac_address const &addr)
+	:
+		Registry<Mac_address>::Element(registry, *this),
+		name(name), addr(addr)
+	{ }
+
+	void report(Xml_generator &report) const
+	{
+		report.node("nic", [&] () {
+			report.attribute("name", name);
+			report.attribute("mac_address", String<20>(addr));
+		});
+	}
+};
+
+
+class Mac_address_registry
+{
+	private:
+
+		Env       &_env;
+		Allocator &_alloc;
+
+		Registry<Mac_address> _registry { };
+
+		Constructible<Expanding_reporter> _reporter { };
+
+		void _report();
+
+	public:
+
+		Mac_address_registry(Env &env, Allocator &alloc)
+		: _env(env), _alloc(alloc) { }
+
+		void apply_config(Xml_node const &config);
+
+		void register_address(Mac_name const &name, Net::Mac_address const &addr);
+};
+
+
+void Mac_address_registry::_report()
+{
+	if (!_reporter.constructed())
+		return;
+
+	_reporter->generate([&] (Reporter::Xml_generator &report) {
+		_registry.for_each([&] (Mac_address const &e) {
+			e.report(report);
+		});
+	});
+}
+
+
+void Mac_address_registry::register_address(Mac_name const &name,
+                                            Net::Mac_address const &addr)
+{
+	bool found = false;
+	_registry.for_each([&] (Mac_address const &e) {
+		if (e.addr == addr)
+			found = true;
+	});
+	if (found) return;
+
+	new (_alloc) Mac_address(_registry, name, addr);
+
+	_report();
+}
+
+
+void Mac_address_registry::apply_config(Xml_node const &config)
+{
+	config.with_optional_sub_node("report", [&] (Xml_node const &xml) {
+		if (xml.attribute_value("mac_address", false))
+			_reporter.construct(_env, "devices", "devices");
+	});
+
+	_report();
+}
+
+
+static Mac_address_registry * _mac_registry = nullptr;
+
+void genode_mac_address_reporter_init(Env &env, Allocator &alloc)
+{
+	static Mac_address_registry registry { env, alloc };
+
+	_mac_registry = &registry;
+}
+
+
+void genode_mac_address_reporter_config(Xml_node const &config)
+{
+	if (_mac_registry)
+		_mac_registry->apply_config(config);
+}
+
+
+extern "C" void genode_mac_address_register(char const *name, genode_mac_address addr)
+{
+	if (_mac_registry)
+		_mac_registry->register_address(Mac_name(name), addr.addr);
+}