MoofTCP: A modern, memory-lean TCP/IP stack for 68k Macs running System 6

Introducing MoofTCP

MoofTCP is a newly developed TCP/IP stack specifically for 68k Macintosh computers operating on System 6. It functions as a direct replacement for Apple's original MacTCP, allowing programs designed for MacTCP to run without modification. The underlying stack is a fresh implementation written in portable C, featuring its own control panel, installer, and a DHCP client.

Addressing MacTCP Limitations

The project was initiated to overcome limitations of the aging MacTCP, particularly on systems with limited resources, such as a Mac Classic with 4 MB of RAM. MacTCP could be slow, memory-intensive, and complex to configure on such setups. MoofTCP prioritizes reliability, low latency for interactive use, and improved throughput for modern network tasks, all while consuming no more resident memory than its predecessor.

Key Features and Compatibility

MoofTCP implements the MacTCP .IPP driver interface (TCP, UDP, ICMP echo) and the name resolver, ensuring full compatibility with existing applications. It supports both DHCP and fixed IP addresses, configurable via its control panel. A 'MoofTCP Lite' version is available, saving approximately 5 KB of system memory by omitting DHCP, catering to machines with extremely tight memory constraints. The installer is designed for ease of use, managing file placement and offering a simple removal option to revert to MacTCP.

Technical Design and Installation

The core TCP/IP stack is built without malloc and global state, and has been tested with sanitizers and fuzzers on desktop environments. Installation involves downloading the appropriate disk image, running the installer, restarting the Mac, configuring network settings in the MoofTCP control panel, and restarting again to go online. The installer also includes diagnostics and is MultiFinder-aware, cleaning up connections when applications quit.