Kernel: Move networking related files into Kernel/Net/.

Kernel/Net/ICMP.h

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <Kernel/Net/MACAddress.h>
+#include <Kernel/Net/IPv4.h>
+
+struct ICMPType {
+enum {
+    EchoReply = 0,
+    EchoRequest = 8,
+};
+};
+
+class [[gnu::packed]] ICMPHeader {
+public:
+    ICMPHeader() { }
+    ~ICMPHeader() { }
+
+    byte type() const { return m_type; }
+    void set_type(byte b) { m_type = b; }
+
+    byte code() const { return m_code; }
+    void set_code(byte b) { m_code = b; }
+
+    word checksum() const { return m_checksum; }
+    void set_checksum(word w) { m_checksum = w; }
+
+    const void* payload() const { return this + 1; }
+    void* payload() { return this + 1; }
+
+private:
+    byte m_type { 0 };
+    byte m_code { 0 };
+    NetworkOrdered<word> m_checksum { 0 };
+    // NOTE: The rest of the header is 4 bytes
+};
+
+static_assert(sizeof(ICMPHeader) == 4);
+
+struct [[gnu::packed]] ICMPEchoPacket {
+    ICMPHeader header;
+    NetworkOrdered<word> identifier;
+    NetworkOrdered<word> sequence_number;
+    void* payload() { return this + 1; }
+    const void* payload() const { return this + 1; }
+};