Kernel: Implement link status in /proc/net/adapters

Kernel/FileSystem/ProcFS.cpp

@@ -318,6 +318,7 @@ Optional<KBuffer> procfs$net_adapters(InodeIdentifier)
         obj.set("bytes_in", adapter.bytes_in());
         obj.set("packets_out", adapter.packets_out());
         obj.set("bytes_out", adapter.bytes_out());
+        obj.set("link_up", adapter.link_up());
         json.append(obj);
     });
     return json.serialized<KBufferBuilder>();

Kernel/Net/E1000NetworkAdapter.cpp

@@ -80,6 +80,17 @@
 #define TSTA_LC (1 << 2) // Late Collision
 #define LSTA_TU (1 << 3) // Transmit Underrun
 
+// STATUS Register
+
+#define STATUS_FD 0x01
+#define STATUS_LU 0x02
+#define STATUS_TXOFF 0x08
+#define STATUS_SPEED 0xC0
+#define STATUS_SPEED_10MB 0x00
+#define STATUS_SPEED_100MB 0x40
+#define STATUS_SPEED_1000MB1 0x80
+#define STATUS_SPEED_1000MB2 0xC0
+
 OwnPtr<E1000NetworkAdapter> E1000NetworkAdapter::autodetect()
 {
     static const PCI::ID qemu_bochs_vbox_id = { 0x8086, 0x100e };
@@ -215,6 +226,11 @@ void E1000NetworkAdapter::read_mac_address()
     }
 }
 
+bool E1000NetworkAdapter::link_up()
+{
+    return (in32(REG_STATUS) & STATUS_LU);
+}
+
 void E1000NetworkAdapter::initialize_rx_descriptors()
 {
     auto ptr = (u32)kmalloc_eternal(sizeof(e1000_rx_desc) * number_of_rx_descriptors + 16);

Kernel/Net/E1000NetworkAdapter.h

@@ -17,6 +17,7 @@ public:
     virtual ~E1000NetworkAdapter() override;
 
     virtual void send_raw(const u8*, int) override;
+    virtual bool link_up() override;
 
 private:
     virtual void handle_irq() override;

Kernel/Net/NetworkAdapter.h

@@ -25,6 +25,7 @@ public:
     const String& name() const { return m_name; }
     MACAddress mac_address() { return m_mac_address; }
     IPv4Address ipv4_address() const { return m_ipv4_address; }
+    virtual bool link_up() { return false; }
 
     void set_ipv4_address(const IPv4Address&);