gbos.git/c/tcp.c, branch mastergbos - a tiny Unix-flavored OS for the Game Boy Color (kernel, shell, coreutils in C, RAM filesystem)https://git.sl0p.foo/gbos.git/atom/c/tcp.c?h=master2026-07-17T12:11:43Zcleanup: drop c/tcp.c (old userland-SLIP TCP client, superseded by kernel TCP/wget)2026-07-17T12:11:43Zuseruser@clank2026-07-17T12:11:43Zurn:sha1:b16397c033de424231de9bb6e1001cbae19366dfnet: DHCP client - lease the IP at boot instead of hardcoding it2026-07-17T12:11:22Zuseruser@clank2026-07-17T12:11:22Zurn:sha1:a2cb756693229c7880d926d2cdde2f838c697415
The address is no longer baked in. net_init starts at 0.0.0.0; a DHCP client
runs as the first thing on boot (init/shell forks it and waits), and only once
it has a lease (or gives up) does the prompt appear.
Kernel:
- IP is configurable: 0.0.0.0 until leased; NET_SETIP op stores it.
- 16-bit frame length. DHCP/BOOTP packets are ~272 bytes, over the old 255-byte
frame cap, so net_slip_send takes a 16-bit length, net_pump assembles into a
320-byte buffer with a 16-bit wNetRxLen, and udp_send writes a 16-bit IP total.
Payloads stay <=255 (kept small on purpose) so the per-protocol datalen math
is unchanged. wNetTx/wNetRxBuf 256->320, SK_RXBUF 208->288.
Userland:
- c/dhcp.c: DISCOVER->OFFER->REQUEST->ACK over a UDP socket, then net_setip();
times out gracefully (shell still boots) if there's no server. sh.c runs it
before the prompt.
Bridge (self-contained DHCP server, no dnsmasq):
- tunbridge.py + netboot intercept UDP->:67 and answer OFFER/ACK leasing
10.0.0.2 (gateway 10.0.0.1); everything else is bridged/NATed as before.
Regression-tested ICMP/UDP/TCP after the 16-bit change. Verified end to end:
dhcp: discovering
dhcp: leased 10.0.0.2
/# ping 10.0.0.1 -> 4/4 (traffic from the leased address)