BrainDance

An OS from Scratch aiming for cyberNet.

BrainDance is an operating system built from scratch. My plans have changed and now its not just an educational project, im going all in for development. I suck at asm but that aint stopping me tho.

Features

• Bootloader: A two-stage 16-bit assembly bootloader. The first stage includes a silent countdown and an optional, simplified BIOS shell. It transitions the CPU to 32-bit protected mode.
• Kernel: A C-based kernel that initializes core systems like the IDT, ISRs, IRQs, and a PIT timer.
• Memory Management: Includes both paging for virtual memory and a simple bump allocator for kernel heap management.
• Drivers: Supports PS/2 keyboard input and ATA (IDE) hard drive for storage.
• Filesystem: A custom-built filesystem, BDFS (BrainDance File System), with support for creating, deleting, reading, and writing files.
• Shell: An interactive command-line interface with commands for file operations, system information (meminfo, time), and direct hardware access (ataread, atawrite).
• Standard Library: A minimal libc implementation providing essential functions like memcpy, strlen, and a kprintf for formatted output.

Building and Running

The project uses a Makefile to automate the build process.

1. Build the OS:

   make

   This will produce a bootable disk image named bdos.img.

2. Run with QEMU:

   qemu-system-i386 -drive format=raw,file=bdos.img

Documentation

For a complete and detailed explanation of the OS architecture, components, and functionality, please see the full documentation in docs.md and the BIOS details in bios.md.

Upcoming Features / Modules

PHASE 1: Bare-Metal Networking Foundation

1. PCI Device Scanning

• Build a PCI configuration space reader (ports 0xCF8, 0xCFC)
• Enumerate all PCI devices
• Detect network cards (Class: 0x02, Subclass: 0x00)

2. Choose a NIC

• Recommended: Intel 82540EM / E1000 (QEMU-supported)
• Alternatives: RTL8139, AMD PCnet

3. Write E1000 Driver

• Map MMIO registers from PCI BAR
• Setup descriptor rings for TX/RX
• Install IRQ handler for NIC
• Implement basic Ethernet frame send/receive
• Print frames via debug shell to verify

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PHASE 2: Protocol Stack

4. Ethernet Protocol

• Parse Ethernet headers
• Route frames by EtherType (0x0800 = IPv4, 0x0806 = ARP)

5. ARP (Address Resolution Protocol)

• Build ARP cache (IP ↔ MAC)
• Handle ARP requests & send ARP replies

6. IPv4

• Parse and construct IP headers
• Route IP packets by protocol (ICMP, UDP, TCP)
• Support basic fragmentation (optional early)

7. ICMP

• Handle ICMP Echo Request & Reply (Ping)
• Add ping <ip> command to BD shell

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PHASE 3: Userland Networking Tools

8. Shell Commands

• ifconfig – show interface info
• ping – test ICMP
• arp – print ARP table

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PHASE 4: Transport Layer

9. UDP

• Implement basic UDP parsing & sending
• Build echo/receive tool for testing

10. TCP (Advanced)

• Handle 3-way handshake
• Implement TCP state machine
• Sliding window + ACKs
• Build echo_server or simple HTTP fetcher

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PHASE 5: Real Utility

11. DNS (UDP)

• Send DNS queries
• Parse responses
• Support A/AAAA record resolution

12. Apps

• curl-like app for HTTP
• Port scanner
• Reverse shell client/server
• File transfer via TCP

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BONUS: Cyberpunk Edition

• Packet sniffer (tcpdump-like)
• Raw socket interface
• Packet crafting/injector
• JohnnyNet custom protocol
• USB WiFi NIC driver (very advanced)

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