Kernel: Add a NetworkTask and a received network packet queue.

It will be easier to deal with incoming packets in a separate task.

Kernel/NetworkTask.cpp

@@ -0,0 +1,33 @@
+#include <Kernel/E1000NetworkAdapter.h>
+#include <Kernel/EthernetFrameHeader.h>
+#include <Kernel/ARPPacket.h>
+#include <Kernel/Process.h>
+
+void NetworkTask_main()
+{
+    auto* e1000_ptr = E1000NetworkAdapter::the();
+    ASSERT(e1000_ptr);
+    auto& e1000 = *e1000_ptr;
+    ARPPacket arp;
+    arp.hardware_type = 1; // Ethernet
+    arp.hardware_address_length = 6; // MAC length
+    arp.protocol_type = 0x0800; // IPv4
+    arp.protocol_address_length = 4; // IP length
+    arp.operation = 1; // 1 (request)
+    e1000.send(MACAddress(), arp);
+
+    kprintf("NetworkTask: Enter main loop.\n");
+    for (;;) {
+        auto packet = e1000.dequeue_packet();
+        if (packet.is_null()) {
+            sleep(100);
+            continue;
+        }
+        if (packet.size() < sizeof(EthernetFrameHeader) + 4) {
+            kprintf("NetworkTask: Packet is too small to be an Ethernet packet! (%d)\n", packet.size());
+            continue;
+        }
+        auto* eth = (const EthernetFrameHeader*)packet.pointer();
+        kprintf("NetworkTask: Handle packet from %s to %s\n", eth->source().to_string().characters(), eth->destination().to_string().characters());
+    }
+}