IPv4: Begin fleshing out TCP support.

Kernel/TCP.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <Kernel/IPv4.h>
+
+class [[gnu::packed]] TCPPacket {
+public:
+    TCPPacket() { }
+    ~TCPPacket() { }
+
+    word source_port() const { return m_source_port; }
+    void set_source_port(word port) { m_source_port = port; }
+
+    word destination_port() const { return m_destination_port; }
+    void set_destination_port(word port) { m_destination_port = port; }
+
+    dword sequence_number() const { return m_sequence_number; }
+    void set_sequence_number(dword number) { m_sequence_number = number; }
+
+    dword ack_number() const { return m_ack_number; }
+    void set_ack_number(dword number) { m_ack_number = number; }
+
+    word flags() const { return m_flags; }
+    void set_flags(word flags) { m_flags = flags; }
+
+    word window_size() const { return m_window_size; }
+    void set_window_size(word window_size) { m_window_size = window_size; }
+
+    word checksum() const { return m_checksum; }
+    void set_checksum(word checksum) { m_checksum = checksum; }
+
+    word urgent() const { return m_urgent; }
+    void set_urgent(word urgent) { m_urgent = urgent; }
+
+    const void* payload() const { return this + 1; }
+    void* payload() { return this + 1; }
+
+private:
+    NetworkOrdered<word> m_source_port;
+    NetworkOrdered<word> m_destination_port;
+    NetworkOrdered<dword> m_sequence_number;
+    NetworkOrdered<dword> m_ack_number;
+
+    NetworkOrdered<word> m_flags;
+    NetworkOrdered<word> m_window_size;
+    NetworkOrdered<word> m_checksum;
+    NetworkOrdered<word> m_urgent;
+};
+
+static_assert(sizeof(UDPPacket) == 8);