nic session: link-state change handling

A Nic::Session client can install a signal handler that is used to
propagate changes of the link-state by calling 'link_state_sigh()'.
The actual link state is queried via 'link_state()'.

The nic-driver interface now provides a Driver_notification callback,
which is used to forward link-state changes from the driver to the
Nic::Session_component.

The following drivers now provide real link state: dde_ipxe, nic_bridge,
and usb_drv. Currently, OpenVPN, Linux nic_drv, and lan9118 do not
support link state and always report link up.

Fixes #1327

repos/dde_ipxe/include/dde_ipxe/nic.h

@@ -15,6 +15,11 @@
 #ifndef _DDE_IPXE__NIC_H_
 #define _DDE_IPXE__NIC_H_
 
+/**
+ * Link-state change callback
+ */
+typedef void (*dde_ipxe_nic_link_cb)(void);
+
 /**
  * Packet reception callback
  *
@@ -27,14 +32,14 @@ typedef void (*dde_ipxe_nic_rx_cb)(unsigned if_index, const char *packet, unsign
 /**
  * Register packet reception callback
  *
- * \param   cb   new callback function
+ * \param   rx_cb    packet-reception callback function
- *
+ * \param   link_cb  link-state change callback function
- * \return  old callback function pointer
  *
  * This registers a function pointer as rx callback. Incoming ethernet packets
  * are passed to this function.
  */
-extern dde_ipxe_nic_rx_cb dde_ipxe_nic_register_rx_callback(dde_ipxe_nic_rx_cb cb);
+extern void dde_ipxe_nic_register_callbacks(dde_ipxe_nic_rx_cb rx_cb,
+                                            dde_ipxe_nic_link_cb link_cb);
 
 /**
  * Send packet
@@ -57,6 +62,15 @@ extern int dde_ipxe_nic_tx(unsigned if_index, const char *packet, unsigned packe
  */
 extern int dde_ipxe_nic_get_mac_addr(unsigned if_index, char *out_mac_addr);
 
+/**
+ * Get current link-state of device
+ *
+ * \param  if_index  index of the receiving network interface
+ *
+ * \return 1 if link is up, 0 if no link is detected
+ */
+extern int dde_ipxe_nic_link_state(unsigned if_index);
+
 /**
  * Initialize network sub-system
  *

repos/dde_ipxe/src/drivers/nic/main.cc

@@ -32,29 +32,32 @@ namespace Ipxe {
 
 			static Driver *instance;
 
-			static void dde_rx_handler(unsigned if_index,
+		private:
-			                           const char *packet,
+
-			                           unsigned packet_len)
+			Nic::Mac_address          _mac_addr;
+			Nic::Rx_buffer_alloc     &_alloc;
+			Nic::Driver_notification &_notify;
+
+			static void _rx_callback(unsigned    if_index,
+			                         const char *packet,
+			                         unsigned    packet_len)
 			{
 				instance->rx_handler(packet, packet_len);
 			}
 
-		private:
+			static void _link_callback() { instance->link_state_changed(); }
-
-			Nic::Mac_address      _mac_addr;
-			Nic::Rx_buffer_alloc &_alloc;
 
 		public:
 
-			Driver(Nic::Rx_buffer_alloc &alloc)
+			Driver(Nic::Rx_buffer_alloc &alloc, Nic::Driver_notification &notify)
-			: _alloc(alloc)
+			: _alloc(alloc), _notify(notify)
 			{
 				PINF("--- init iPXE NIC");
 				int cnt = dde_ipxe_nic_init();
 				PINF("    number of devices: %d", cnt);
 
-				PINF("--- init rx_callbacks");
+				PINF("--- init callbacks");
-				dde_ipxe_nic_register_rx_callback(dde_rx_handler);
+				dde_ipxe_nic_register_callbacks(_rx_callback, _link_callback);
 
 				dde_ipxe_nic_get_mac_addr(1, _mac_addr.addr);
 				PINF("--- get MAC address %02x:%02x:%02x:%02x:%02x:%02x",
@@ -70,16 +73,23 @@ namespace Ipxe {
 					Genode::memcpy(buffer, packet, packet_len);
 					_alloc.submit();
 				} catch (...) {
-					PDBG("failed to process received packet");	
+					PDBG("failed to process received packet");
 				}
 			}
 
+			void link_state_changed() { _notify.link_state_changed(); }
+
 
 			/***************************
 			 ** Nic::Driver interface **
 			 ***************************/
 
-			Nic::Mac_address mac_address() { return _mac_addr; }
+			Nic::Mac_address mac_address() override { return _mac_addr; }
+
+			bool link_state() override
+			{
+				return dde_ipxe_nic_link_state(1);
+			}
 
 			void tx(char const *packet, Genode::size_t size)
 			{
@@ -87,7 +97,6 @@ namespace Ipxe {
 					PWRN("Sending packet failed!");
 			}
 
-
 			/******************************
 			 ** Irq_activation interface **
 			 ******************************/
@@ -97,9 +106,10 @@ namespace Ipxe {
 
 	class Driver_factory : public Nic::Driver_factory
 	{
-		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc)
+		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc,
+		                    Nic::Driver_notification &notify)
 		{
-			Driver::instance = new (Genode::env()->heap()) Ipxe::Driver(alloc);
+			Driver::instance = new (Genode::env()->heap()) Ipxe::Driver(alloc, notify);
 			return Driver::instance;
 		}
 

repos/dde_ipxe/src/drivers/nic_stat/main.cc

@@ -36,32 +36,35 @@ namespace Ipxe {
 
 			static Driver *instance;
 
-			static void dde_rx_handler(unsigned if_index,
+		private:
-			                           const char *packet,
+
-			                           unsigned packet_len)
+			Nic::Mac_address          _mac_addr;
+			Nic::Rx_buffer_alloc     &_alloc;
+			Nic::Driver_notification &_notify;
+
+			Timer::Connection _timer;
+			Nic::Measurement  _stat;
+
+			static void _rx_callback(unsigned    if_index,
+			                         const char *packet,
+			                         unsigned    packet_len)
 			{
 				instance->rx_handler_stat(packet, packet_len);
 			}
 
-		private:
+			static void _link_callback() { instance->link_state_changed(); }
-
-			Nic::Mac_address      _mac_addr;
-			Nic::Rx_buffer_alloc &_alloc;
-
-			Timer::Connection _timer;
-			Nic::Measurement _stat;
 
 		public:
 
-			Driver(Nic::Rx_buffer_alloc &alloc)
+			Driver(Nic::Rx_buffer_alloc &alloc, Nic::Driver_notification &notify)
-			: _alloc(alloc), _stat(_timer)
+			: _alloc(alloc), _notify(notify), _stat(_timer)
 			{
 				PINF("--- init iPXE NIC");
 				int cnt = dde_ipxe_nic_init();
 				PINF("    number of devices: %d", cnt);
 
-				PINF("--- init rx_callbacks");
+				PINF("--- init callbacks");
-				dde_ipxe_nic_register_rx_callback(dde_rx_handler);
+				dde_ipxe_nic_register_callbacks(_rx_callback, _link_callback);
 
 				dde_ipxe_nic_get_mac_addr(1, _mac_addr.addr);
 				PINF("--- get MAC address %02x:%02x:%02x:%02x:%02x:%02x",
@@ -90,6 +93,8 @@ namespace Ipxe {
 				_alloc.submit();
 			}
 
+			void link_state_changed() { _notify.link_state_changed(); }
+
 
 			/***************************
 			 ** Nic::Driver interface **
@@ -97,6 +102,11 @@ namespace Ipxe {
 
 			Nic::Mac_address mac_address() { return _mac_addr; }
 
+			bool link_state() override
+			{
+				return dde_ipxe_nic_link_state(1);
+			}
+
 			void tx(char const *packet, Genode::size_t size)
 			{
 				if (dde_ipxe_nic_tx(1, packet, size))
@@ -112,9 +122,9 @@ namespace Ipxe {
 
 	class Driver_factory : public Nic::Driver_factory
 	{
-		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc)
+		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc, Nic::Driver_notification &notify)
 		{
-			Driver::instance = new (Genode::env()->heap()) Ipxe::Driver(alloc);
+			Driver::instance = new (Genode::env()->heap()) Ipxe::Driver(alloc, notify);
 			return Driver::instance;
 		}
 

repos/dde_ipxe/src/lib/dde_ipxe/nic.c

@@ -48,9 +48,15 @@ static struct dde_kit_sem *bh_sema;
 static struct net_device *net_dev;
 
 /**
- * RX callback function pointer
+ * Link-state change detected
  */
-static dde_ipxe_nic_rx_cb rx_callback;
+static int link_state_changed;
+
+/**
+ * Callback function pointers
+ */
+static dde_ipxe_nic_link_cb link_callback;
+static dde_ipxe_nic_rx_cb   rx_callback;
 
 /**
  * Known iPXE driver structures (located in the driver binaries)
@@ -71,7 +77,6 @@ static struct pci_driver *pci_drivers[] = {
 	&pcnet32_driver
 };
 
-
 /**
  * Update BARs of PCI device
  */
@@ -201,9 +206,15 @@ static void irq_handler(void *p)
 {
 	ENTER;
 
+	/* check for the link-state to change on each interrupt */
+	int link_ok = netdev_link_ok(net_dev);
+
+	/* poll the device for packets and also link-state changes */
 	netdev_poll(net_dev);
 	dde_kit_sem_up(bh_sema);
 
+	link_state_changed = (link_ok != netdev_link_ok(net_dev));
+
 	LEAVE;
 }
 
@@ -220,6 +231,15 @@ static void bh_handler(void *p)
 
 		ENTER;
 
+		/* report link-state changes */
+		if (link_state_changed) {
+			LEAVE;
+			if (link_callback)
+				link_callback();
+			ENTER;
+			link_state_changed = 0;
+		}
+
 		struct io_buffer *iobuf;
 		while ((iobuf = netdev_rx_dequeue(net_dev))) {
 			LEAVE;
@@ -238,15 +258,30 @@ static void bh_handler(void *p)
  ** API implementation **
  ************************/
 
-dde_ipxe_nic_rx_cb dde_ipxe_nic_register_rx_callback(dde_ipxe_nic_rx_cb cb)
+void dde_ipxe_nic_register_callbacks(dde_ipxe_nic_rx_cb rx_cb,
+                                     dde_ipxe_nic_link_cb link_cb)
 {
 	ENTER;
 
-	dde_ipxe_nic_rx_cb old = rx_callback;
+	rx_callback   = rx_cb;
-	rx_callback            = cb;
+	link_callback = link_cb;
 
 	LEAVE;
-	return old;
+}
+
+
+int dde_ipxe_nic_link_state(unsigned if_index)
+{
+	if (if_index != 1)
+		return -1;
+
+	ENTER;
+
+	int link_state = netdev_link_ok(net_dev);
+
+	LEAVE;
+
+	return link_state;
 }
 
 

repos/dde_linux/src/lib/usb/include/nic/component.h

@@ -80,6 +80,11 @@ namespace Nic {
 		 */
 		virtual Mac_address mac_address() = 0;
 
+		/**
+		 * Return current link-state (true if link detected)
+		 */
+		virtual bool link_state() = 0;
+
 		/**
 		 * Set session belonging to this driver
 		 */
@@ -130,6 +135,8 @@ namespace Nic {
 			bool              _tx_alloc;  /* get next packet from client or use _tx_packet */
 			Packet_descriptor _tx_packet; /* saved packet in case of driver errors */
 
+			Signal_context_capability _link_state_sigh;
+
 			void _send_packet_avail_signal() {
 				Signal_transmitter(_tx.sigh_packet_avail()).submit(); }
 
@@ -256,8 +263,23 @@ namespace Nic {
 				_tx_alloc(true)
 				{ _device->session(this); }
 
+			/**
+			 * Link state changed (called from driver)
+			 */
+			void link_state_changed()
+			{
+				if (_link_state_sigh.valid())
+					Genode::Signal_transmitter(_link_state_sigh).submit();
+			}
+
 			Mac_address mac_address() { return _device->mac_address(); }
 
+			bool link_state() override {
+				return _device->link_state(); }
+
+			void link_state_sigh(Genode::Signal_context_capability sigh) {
+				_link_state_sigh = sigh; }
+
 			/**
 			 * Send packet to client (called form driver)
 			 */

repos/dde_linux/src/lib/usb/nic/nic.cc

@@ -144,6 +144,7 @@ class Nic_device : public Nic::Device
 		struct net_device *_ndev;  /* Linux-net device */
 		fixup_t            _tx_fixup;
 		bool const         _burst;
+		bool               _has_link { false };
 
 	public:
 
@@ -177,11 +178,29 @@ class Nic_device : public Nic::Device
 		static Nic_device *add(struct net_device *ndev) {
 			return new (Genode::env()->heap()) Nic_device(ndev); }
 
+		/**
+		 * Report link state
+		 */
+		void link_state(bool link)
+		{
+			/* only report changes of the link state */
+			if (link == _has_link)
+				return;
+
+			_has_link = link;
+
+			if (_session)
+				_session->link_state_changed();
+		}
+
+
 
 		/**********************
 		 ** Device interface **
 		 **********************/
 
+		bool link_state() override { return _has_link; }
+
 		/**
 		 * Submit packet to driver
 		 */
@@ -344,12 +363,16 @@ int netif_carrier_ok(const struct net_device *dev)
 void netif_carrier_on(struct net_device *dev)
 {
 	dev->state &= ~(1 << __LINK_STATE_NOCARRIER);
+	if (_nic)
+		_nic->link_state(true);
 }
 
 
 void netif_carrier_off(struct net_device *dev)
 {
 	dev->state |= 1 << __LINK_STATE_NOCARRIER;
+	if (_nic)
+		_nic->link_state(false);
 }
 
 #ifdef GENODE_NET_STAT

repos/os/include/nic/component.h

@@ -39,13 +39,16 @@ namespace Nic {
 
 
 class Nic::Session_component : public Genode::Allocator_avl,
-                               public Session_rpc_object, public Rx_buffer_alloc
+                               public Session_rpc_object, public Rx_buffer_alloc,
+                               public Driver_notification
 {
 	private:
 
 		Driver_factory &_driver_factory;
 		Driver         &_driver;
 
+		Genode::Signal_context_capability _link_state_sigh;
+
 		/* rx packet descriptor */
 		Genode::Packet_descriptor _curr_rx_packet;
 
@@ -126,7 +129,7 @@ class Nic::Session_component : public Genode::Allocator_avl,
 			                   Genode::env()->ram_session()->alloc(rx_buf_size),
 			                   static_cast<Genode::Range_allocator *>(this), ep),
 			_driver_factory(driver_factory),
-			_driver(*driver_factory.create(*this)),
+			_driver(*driver_factory.create(*this, *this)),
 			_tx_thread(_tx.sink(), _driver)
 		{ }
 
@@ -138,12 +141,21 @@ class Nic::Session_component : public Genode::Allocator_avl,
 			_driver_factory.destroy(&_driver);
 		}
 
+		/***********************************
+		 ** Driver-notification interface **
+		 ***********************************/
+
+		void link_state_changed() override
+		{
+			if (_link_state_sigh.valid())
+				Genode::Signal_transmitter(_link_state_sigh).submit();
+		}
 
 		/*******************************
 		 ** Rx_buffer_alloc interface **
 		 *******************************/
 
-		void *alloc(Genode::size_t size)
+		void *alloc(Genode::size_t size) override
 		{
 			/* assign rx packet descriptor */
 			_curr_rx_packet = _rx.source()->alloc_packet(size);
@@ -151,7 +163,7 @@ class Nic::Session_component : public Genode::Allocator_avl,
 			return _rx.source()->packet_content(_curr_rx_packet);
 		}
 
-		void submit()
+		void submit() override
 		{
 			/* check for acknowledgements from the client */
 			while (_rx.source()->ack_avail()) {
@@ -175,8 +187,14 @@ class Nic::Session_component : public Genode::Allocator_avl,
 		 ****************************/
 
 		Mac_address mac_address() { return _driver.mac_address(); }
+		bool        link_state()  { return _driver.link_state(); }
 		Tx::Sink*   tx_sink()     { return _tx.sink();   }
 		Rx::Source* rx_source()   { return _rx.source(); }
+
+		void link_state_sigh(Genode::Signal_context_capability sigh) override
+		{
+			_link_state_sigh = sigh;
+		}
 };
 
 

repos/os/include/nic/driver.h

@@ -22,6 +22,7 @@ namespace Nic {
 	struct Rx_buffer_alloc;
 	struct Driver;
 	struct Driver_factory;
+	struct Driver_notification;
 }
 
 
@@ -42,6 +43,12 @@ struct Nic::Rx_buffer_alloc
 };
 
 
+/**
+ * Interface for driver-to-component notifications
+ */
+struct Nic::Driver_notification { virtual void link_state_changed() = 0; };
+
+
 /**
  * Interface to be implemented by the device-specific driver code
  */
@@ -52,6 +59,11 @@ struct Nic::Driver : Genode::Irq_handler
 	 */
 	virtual Mac_address mac_address() = 0;
 
+	/**
+	 * Return link state (true if link detected)
+	 */
+	virtual bool link_state() = 0;
+
 	/**
 	 * Transmit packet
 	 *
@@ -83,8 +95,10 @@ struct Nic::Driver_factory
 	 *
 	 * \param rx_buffer_alloc  buffer allocator used for storing incoming
 	 *                         packets
+	 * \param notifier         callback for notifications
 	 */
-	virtual Driver *create(Rx_buffer_alloc &rx_buffer_alloc) = 0;
+	virtual Driver *create(Rx_buffer_alloc &rx_buffer_alloc,
+	                       Driver_notification &notify) = 0;
 
 	/**
 	 * Destroy driver

repos/os/include/nic_session/client.h

@@ -56,6 +56,13 @@ class Nic::Session_client : public Genode::Rpc_client<Session>
 		Rx *rx_channel() { return &_rx; }
 		Tx::Source *tx() { return _tx.source(); }
 		Rx::Sink   *rx() { return _rx.sink(); }
+
+		void link_state_sigh(Genode::Signal_context_capability sigh) override
+		{
+			call<Rpc_link_state_sigh>(sigh);
+		}
+
+		bool link_state() override { return call<Rpc_link_state>(); }
 };
 
 #endif /* _INCLUDE__NIC_SESSION__CLIENT_H_ */

repos/os/include/nic_session/nic_session.h

@@ -93,6 +93,15 @@ struct Nic::Session : Genode::Session
 	 */
 	virtual Rx::Sink *rx() { return 0; }
 
+	/**
+	 * Request current link state of network adapter (true means link detected)
+	 */
+	virtual bool link_state() = 0;
+
+	/**
+	 * Register signal handler for link state changes
+	 */
+	virtual void link_state_sigh(Genode::Signal_context_capability sigh) = 0;
 
 	/*******************
 	 ** RPC interface **
@@ -101,8 +110,12 @@ struct Nic::Session : Genode::Session
 	GENODE_RPC(Rpc_mac_address, Mac_address, mac_address);
 	GENODE_RPC(Rpc_tx_cap, Genode::Capability<Tx>, _tx_cap);
 	GENODE_RPC(Rpc_rx_cap, Genode::Capability<Rx>, _rx_cap);
+	GENODE_RPC(Rpc_link_state, bool, link_state);
+	GENODE_RPC(Rpc_link_state_sigh, void, link_state_sigh,
+	           Genode::Signal_context_capability);
 
-	GENODE_RPC_INTERFACE(Rpc_mac_address, Rpc_tx_cap, Rpc_rx_cap);
+	GENODE_RPC_INTERFACE(Rpc_mac_address, Rpc_link_state,
+	                     Rpc_link_state_sigh, Rpc_tx_cap, Rpc_rx_cap);
 };
 
 #endif /* _INCLUDE__NIC_SESSION__NIC_SESSION_H_ */

repos/os/src/drivers/nic/lan9118/lan9118.h

@@ -72,6 +72,7 @@ class Lan9118 : public Nic::Driver
 		Timer::Connection                 _timer;
 		Nic::Rx_buffer_alloc             &_rx_buffer_alloc;
 		Nic::Mac_address                  _mac_addr;
+		Nic::Driver_notification         &_notify;
 
 		enum { IRQ_STACK_SIZE = 4096 };
 		Genode::Irq_activation _irq_activation;
@@ -201,11 +202,13 @@ class Lan9118 : public Nic::Driver
 		 * \throw  Device_not_supported
 		 */
 		Lan9118(Genode::addr_t mmio_base, Genode::size_t mmio_size, int irq,
-		        Nic::Rx_buffer_alloc &rx_buffer_alloc)
+		        Nic::Rx_buffer_alloc &rx_buffer_alloc,
+		        Nic::Driver_notification &notify)
 		:
 			_mmio(mmio_base, mmio_size),
 			_reg_base(_mmio.local_addr<Genode::uint32_t>()),
 			_rx_buffer_alloc(rx_buffer_alloc),
+			_notify(notify),
 			_irq_activation(irq, *this, IRQ_STACK_SIZE)
 		{
 			unsigned long const id_rev     = _reg_read(ID_REV),
@@ -287,6 +290,8 @@ class Lan9118 : public Nic::Driver
 			_mac_csr_write(MAC_CR, 0);
 		}
 
+		void link_state_changed() { _notify.link_state_changed(); }
+
 
 		/***************************
 		 ** Nic::Driver interface **
@@ -297,6 +302,12 @@ class Lan9118 : public Nic::Driver
 			return _mac_addr;
 		}
 
+		bool link_state()
+		{
+			/* XXX always return true for now */
+			return true;
+		}
+
 		void tx(char const *packet, Genode::size_t size)
 		{
 			/* limit size to 11 bits, the maximum supported by lan9118 */

repos/os/src/drivers/nic/lan9118/main.cc

@@ -37,10 +37,11 @@ int main(int, char **)
 	 */
 	struct Lan9118_driver_factory : Nic::Driver_factory
 	{
-		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc)
+		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc,
+		                    Nic::Driver_notification &notify)
 		{
 			return new (env()->heap())
-				Lan9118(LAN9118_PHYS, LAN9118_SIZE, LAN9118_IRQ, alloc);
+				Lan9118(LAN9118_PHYS, LAN9118_SIZE, LAN9118_IRQ, alloc, notify);
 		}
 
 		void destroy(Nic::Driver *driver)

repos/os/src/drivers/nic/linux/main.cc

@@ -67,8 +67,9 @@ class Linux_driver : public Nic::Driver
 			}
 		};
 
-		Nic::Mac_address      _mac_addr;
+		Nic::Mac_address          _mac_addr;
-		Nic::Rx_buffer_alloc &_alloc;
+		Nic::Rx_buffer_alloc     &_alloc;
+		Nic::Driver_notification &_notify;
 
 		char      _packet_buffer[1514];  /* maximum ethernet packet length */
 		int       _tap_fd;
@@ -114,8 +115,11 @@ class Linux_driver : public Nic::Driver
 
 	public:
 
-		Linux_driver(Nic::Rx_buffer_alloc &alloc)
+		Linux_driver(Nic::Rx_buffer_alloc &alloc,
-		: _alloc(alloc), _tap_fd(_setup_tap_fd()), _rx_thread(_tap_fd, *this)
+		             Nic::Driver_notification &notify)
+		:
+			_alloc(alloc), _notify(notify),
+			_tap_fd(_setup_tap_fd()), _rx_thread(_tap_fd, *this)
 		{
 			/* try using configured MAC address */
 			try {
@@ -141,6 +145,8 @@ class Linux_driver : public Nic::Driver
 			_rx_thread.start();
 		}
 
+		void link_state_changed() { _notify.link_state_changed(); }
+
 
 		/***************************
 		 ** Nic::Driver interface **
@@ -148,6 +154,12 @@ class Linux_driver : public Nic::Driver
 
 		Nic::Mac_address mac_address() { return _mac_addr; }
 
+		bool link_state()
+		{
+			/* XXX return always true for now */
+			return true;
+		}
+
 		void tx(char const *packet, Genode::size_t size)
 		{
 			int ret;
@@ -200,9 +212,10 @@ int main(int, char **)
 	 */
 	struct Linux_driver_factory : Nic::Driver_factory
 	{
-		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc)
+		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc,
+		                    Nic::Driver_notification &notify)
 		{
-			return new (env()->heap()) Linux_driver(alloc);
+			return new (env()->heap()) Linux_driver(alloc, notify);
 		}
 
 		void destroy(Nic::Driver *driver)

repos/os/src/server/nic_bridge/component.cc

@@ -102,6 +102,10 @@ void Session_component::_free_ipv4_node()
 }
 
 
+bool Session_component::link_state() {
+	return Net::Env::nic()->link_state(); }
+
+
 void Session_component::set_ipv4_address(Ipv4_packet::Ipv4_address ip_addr)
 {
 	_free_ipv4_node();

repos/os/src/server/nic_bridge/component.h

@@ -105,6 +105,8 @@ namespace Net {
 			Mac_address_node   _mac_node;
 			Ipv4_address_node *_ipv4_node;
 
+			Genode::Signal_context_capability _link_state_sigh;
+
 			void _free_ipv4_node();
 
 		public:
@@ -137,8 +139,23 @@ namespace Net {
 				return m;
 			}
 
+			void link_state_changed()
+			{
+				if (_link_state_sigh.valid())
+					Genode::Signal_transmitter(_link_state_sigh).submit();
+			}
+
 			void set_ipv4_address(Ipv4_packet::Ipv4_address ip_addr);
 
+			/****************************************
+			 ** Nic::Driver notification interface **
+			 ****************************************/
+
+			bool link_state();
+
+			void link_state_sigh(Genode::Signal_context_capability sigh) {
+				_link_state_sigh = sigh; }
+
 			/******************************
 			 ** Packet_handler interface **
 			 ******************************/

repos/os/src/server/nic_bridge/nic.cc

@@ -134,4 +134,5 @@ Net::Nic::Nic()
 	_nic.rx_channel()->sigh_packet_avail(_sink_submit);
 	_nic.tx_channel()->sigh_ack_avail(_source_ack);
 	_nic.tx_channel()->sigh_ready_to_submit(_source_submit);
+	_nic.link_state_sigh(_client_link_state);
 }

repos/os/src/server/nic_bridge/nic.h

@@ -45,6 +45,7 @@ class Net::Nic : public Net::Packet_handler
 		::Nic::Connection          *nic() { return &_nic; }
 		Ethernet_frame::Mac_address mac() { return _mac; }
 
+		bool link_state() { return _nic.link_state(); }
 
 		/******************************
 		 ** Packet_handler interface **

repos/os/src/server/nic_bridge/packet_handler.cc

@@ -54,6 +54,16 @@ void Packet_handler::_ready_to_ack(unsigned)
 }
 
 
+void Packet_handler::_link_state(unsigned)
+{
+	Mac_address_node *node = Env::vlan()->mac_list()->first();
+	while (node) {
+		node->component()->link_state_changed();
+		node = node->next();
+	}
+}
+
+
 void Packet_handler::broadcast_to_clients(Ethernet_frame *eth, Genode::size_t size)
 {
 	/* check whether it's really a broadcast packet */
@@ -121,5 +131,6 @@ Packet_handler::Packet_handler()
 : _sink_ack(*Net::Env::receiver(), *this, &Packet_handler::_ack_avail),
   _sink_submit(*Net::Env::receiver(), *this, &Packet_handler::_ready_to_submit),
   _source_ack(*Net::Env::receiver(), *this, &Packet_handler::_ready_to_ack),
-  _source_submit(*Net::Env::receiver(), *this, &Packet_handler::_packet_avail)
+  _source_submit(*Net::Env::receiver(), *this, &Packet_handler::_packet_avail),
+  _client_link_state(*Net::Env::receiver(), *this, &Packet_handler::_link_state)
 { }

repos/os/src/server/nic_bridge/packet_handler.h

@@ -65,12 +65,18 @@ class Net::Packet_handler
 		 */
 		void _packet_avail(unsigned) { }
 
+		/**
+		 * the link-state of changed
+		 */
+		void _link_state(unsigned);
+
 	protected:
 
 		Genode::Signal_dispatcher<Packet_handler> _sink_ack;
 		Genode::Signal_dispatcher<Packet_handler> _sink_submit;
 		Genode::Signal_dispatcher<Packet_handler> _source_ack;
 		Genode::Signal_dispatcher<Packet_handler> _source_submit;
+		Genode::Signal_dispatcher<Packet_handler> _client_link_state;
 
 	public:
 

repos/os/src/server/nic_loopback/main.cc

@@ -142,6 +142,14 @@ namespace Nic {
 				Mac_address result = {{1,2,3,4,5,6}};
 				return result;
 			}
+
+			bool link_state()
+			{
+				/* XXX always return true, for now */
+				return true;
+			}
+
+			void link_state_sigh(Genode::Signal_context_capability sigh) { }
 	};
 
 	class Root : public Genode::Root_component<Session_component>

repos/ports/src/app/openvpn/main.cc

@@ -5,7 +5,7 @@
  */
 
 /*
- * Copyright (C) 2014 Genode Labs GmbH
+ * Copyright (C) 2014-2015 Genode Labs GmbH
  *
  * This file is part of the Genode OS framework, which is distributed
  * under the terms of the GNU General Public License version 2.
@@ -87,8 +87,9 @@ class Nic_driver : public Tuntap_device,
 {
 	private:
 
-		Nic::Mac_address      _mac_addr {{ 0x02, 0x00, 0x00, 0x00, 0x00, 0x01 }};
+		Nic::Mac_address          _mac_addr {{ 0x02, 0x00, 0x00, 0x00, 0x00, 0x01 }};
-		Nic::Rx_buffer_alloc &_alloc;
+		Nic::Rx_buffer_alloc     &_alloc;
+		Nic::Driver_notification &_notify;
 
 		char const *_packet;
 
@@ -101,10 +102,9 @@ class Nic_driver : public Tuntap_device,
 
 	public:
 
-		Nic_driver(Nic::Rx_buffer_alloc &alloc)
+		Nic_driver(Nic::Rx_buffer_alloc &alloc, Nic::Driver_notification &notify)
 		:
-			_alloc(alloc),
+			_alloc(alloc), _notify(notify), _packet(0)
-			_packet(0)
 		{
 			if (pipe(_pipefd)) {
 				PERR("could not create pipe");
@@ -114,6 +114,7 @@ class Nic_driver : public Tuntap_device,
 
 		~Nic_driver() { PDBG("should probably be implemented"); }
 
+		void link_state_changed() { _notify.link_state_changed(); }
 
 		/***************************
 		 ** Nic::Driver interface **
@@ -121,6 +122,12 @@ class Nic_driver : public Tuntap_device,
 
 		Nic::Mac_address mac_address() { return _mac_addr; }
 
+		bool link_state()
+		{
+			/* XXX always return true for now */
+			return true;
+		}
+
 		void tx(char const *packet, Genode::size_t size)
 		{
 			PDBGV("packet:0x%p size:%zu", packet, size);
@@ -185,11 +192,12 @@ struct Main
 		Nic_driver     *drv { 0 };
 		Openvpn_thread *openvpn { 0 };
 
-		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc)
+		Nic::Driver *create(Nic::Rx_buffer_alloc &alloc,
+		                    Nic::Driver_notification &notify)
 		{
 			/* there can be only one */
 			if (!drv) {
-				drv = new (Genode::env()->heap()) Nic_driver(alloc);
+				drv = new (Genode::env()->heap()) Nic_driver(alloc, notify);
 
 				/**
 				 * Setting the pointer in this manner is quite hackish but it has