Operation WIRE STORM

Specification

We have crafted a custom protocol for broadcasting critical information between clients and servers called the CoreTech Message Protocol (CTMP).

Your mission is to write a forwarding/proxy server for the CoreTech Message Protocol (CTMP) over TCP. The server can be written in a native language of your choice from the following:

• C
• C++
• Rust

Due to the sensitivity of this protocol, the solution should not use third-party libraries other than the chosen language’s standard library.

CoreTech Message Protocol

    0               1               2               3
    0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | MAGIC 0xCC    | PADDING       | LENGTH                      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | PADDING                                                     |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | DATA ...................................................... |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7

Each field is detailed with the following:

• MAGIC: 8 bits 0xCC.
• PADDING: 8 bits - 0x00.
• LENGTH: 16 bits - unsigned - network byte order - data size excluding the header itself.
• DATA: remaining data to be transmitted.

Server

The server must:

• Allow a single source client to connect on port 33333.
• Allow multiple destination clients to connect on port 44444.
• Accept CTMP messages from the source and forward to all destination clients. These should be forwarded in the order they are received.
• Validate the magic and length of the data before forwarding. Any messages with an excessive length must be dropped.

Further Information

When assessing submissions we will be looking for solutions that are, in no particular order:

• readable
• documented
• efficient

Tests

To allow for local testing of solutions, our operatives have deployed some Python 3.12 tests for validation.

These can be run without any additional libraries:

python3 tests.py

The tests will output a success message if all pass, or an error message otherwise.

Good luck!