BSD TCP/IP for Kyu

• Introduction
• Why BSD?

• TCP state transition diagram (PDF)

• Files and directory structure.
• Components (especially ones I intend to bypass)
• Example daytime client (UDP and TCP)
• Who or what is "tuba"
• First cut at TCP code
• OSI protocols
• Network driver (hp300 "lance" chip, chapters 4 and 5)
• Socket API

• NetBSD
• First stab at a Makefile
• Global variables
• The "dtom" macro
• Warnings and missing pieces
• Missing functions
• Queues: insque, remque and more

• Receiving packets
• Stubs to make it all link, load, and run
• Using Wireshark
• socket - setting up the inpcb and tcpcb
• Bind - accepting a connection
• tcp_usrreq and user API
• The in_ifaddr list

• Sleep and wakeup
• Write and sendmsg
• Connect and debugging
• Checksums
• Connection close and shutdown
• FINWAIT and connection limitations

Progress reports

• Progress November 11, 2022
• Progress December 3, 2022
• Progress December 4, 2022 (working echo server)
• Progress December 14, 2022 (success)

Bugs - with lots of notes

• Race conditions, spl, and semaphores
• Socket recv - blocking and signaling (fixed)
• Long send panic and bug (fix with big locks)
• Unexpected shutdown bug (fixed)

A bug in Kyu?

• Kyu bugs -- can this be?
• It just hangs!
• Kyu in review
• The kyu hang revisited (12-30-2022)
• The kyu hang continued (1-2-2023)
• The kyu hang continued (1-3-2023)
• One hang explained (1-3-2023)

More bugs

• Data abort (1-4-2023)
• Data abort continued (1-5-2023)
• Questionable queue counts (1-6-2022)

TODO - thing in progress or yet to be started

• More testing
• Testing on the BBB (very interesting!)

• SPL and locks in retrospect
• Initialization
• General TODO list
• Routing information in the TCP code?