gbos.git/tools/gateway.py, branch master

net: IP stack milestone B - UDP echo (pseudo-header checksum)

2026-07-17T00:05:26Z

Refactor netd into a protocol dispatcher (IP -> ICMP/UDP) and add UDP echo: swap addresses + ports and recompute the UDP checksum over the pseudo-header (src/dst IP + proto + length) plus the datagram. This is the same pseudo- header TCP uses, so it de-risks the next milestone. tools/gateway.py --mode udp sends a datagram and verifies the echo. Verified: 'hello udp gbos' echoes back with cksum=ok.

net: real IP stack, milestone A - ICMP echo (you can ping a Game Boy)

2026-07-17T00:03:05Z

Start of an actual TCP/IP stack on gbos (TLS stays in a proxy). netd is a userland IP responder over SLIP: our address is 10.0.0.2, the SLIP peer 10.0.0.1. It parses IPv4 headers, answers ICMP echo requests, and rebuilds the packet with correct IP + ICMP checksums (RFC 1071 one's-complement sum, carry-folded - works fine on the SM83). c/netd.c + register; tools/gateway.py gains --mode ping: it crafts ICMP echo requests over SLIP and verifies the replies. Verified: `netd` answers 4 pings, gateway reports reply from 10.0.0.2 with cksum=ok for each. Next: UDP, then TCP.

net: chat client - async receive + OSK send over the link port

2026-07-16T23:39:29Z

The application layer of the link-port demo, and it ties the whole system together: the LCD terminal displays, the on-screen keyboard types, and the link port carries a live chat. Kernel: sys_srecv_nb (non-blocking link receive; A=byte, CF=none) and sys_pollin (poll the OSK for a typed char without blocking) - syscalls 31/32. Both are what a poll loop needs to receive and type at once. Userland: c/chat.c runs a poll loop - it feeds non-blocking bytes through a SLIP receive state machine and prints whole incoming frames as messages, while pollin() drives the on-screen keyboard; SELECT shows the keys, type a line, START sends it as a frame. libc srecv_nb()/pollin(). Host: tools/gateway.py --mode chat is a simple bot peer (echoes each GB message and injects a few async ones); --keys can drive the OSK for tests. Verified: the gateway pushes 'welcome', ' hey gameboy!', ' nice link cable' unprompted and the GB displays all three (async receive); typing 'hi' on the OSK echoes it and emits the SLIP frame \xC0hi\xC0 (send). A Game Boy in the chat, keyboard on screen, over the link cable.

net: wget - real HTTP over the link port via the gateway

2026-07-16T23:31:38Z

Grow the link-port demo from echo to actual network access. The Game Boy still only does SLIP framing + display; the host gateway does DNS/TCP/HTTP. - c/netlib.h: SLIP framing factored out (header-only, per-program copy). necho.c now uses it too. - c/wget.c: `wget URL` frames the URL, then prints the reply body. The gateway streams the body back as typed frames: 'D' ... 'E'. - tools/gateway.py: add --mode http (urlopen the frame as a URL, cap the body, chunk it) alongside --mode echo; --cmd runs any gbos command. Verified: `wget example.com` streams back the full Example Domain HTML onto the terminal; `wget sl0p.foo` fetches the real page. A Game Boy on the web, over the link cable.

net: SLIP framing over the link port + a host gateway (echo round-trip)

2026-07-16T23:28:23Z

First step of link-port networking. The LCD terminal + OSK freed the serial port from console duty, so it can be the network link. Kernel (src/net.asm): raw link-port serial that bypasses the console/ terminal - sys_ssend (transmit, GB drives the clock) and sys_srecv (receive, GB slave, blocks by yielding). Syscalls 29/30. Userland: libc ssend()/srecv(); c/necho.c does SLIP (RFC 1055) framing over them - send a packet, receive the reply, print it. Host: tools/gateway.py wraps the emulator, owns its link serial, speaks SLIP, and (for now) echoes every frame back - the "link cable adapter". Console (ASCII) bytes on the same channel are printed for visibility. Verified: `necho` sends a SLIP frame, the gateway decodes+echoes it, and gbos prints the reply - a real framed round-trip over the Game Boy link port. Next: swap the echo for actual network ops (DNS/HTTP or IRC/chat).