From a2cb756693229c7880d926d2cdde2f838c697415 Mon Sep 17 00:00:00 2001 From: user Date: Fri, 17 Jul 2026 14:11:22 +0200 Subject: net: DHCP client - lease the IP at boot instead of hardcoding it 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) --- c/sh.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'c/sh.c') diff --git a/c/sh.c b/c/sh.c index a8dd09d..3178894 100644 --- a/c/sh.c +++ b/c/sh.c @@ -155,6 +155,12 @@ void main(void) { char *tok[16]; char cwd[40]; cwd[0] = '/'; cwd[1] = 0; + /* bring up networking first: run the DHCP client and wait for it to finish + (got a lease, or gave up). Only then drop to the prompt. */ + { + unsigned char d = lookup("dhcp"); + if (d != NOFD) { if (fork() == 0) exec(d); else wait(); } + } for (;;) { unsigned char nt, i, pipepos, c, bg; /* reap finished background jobs */ -- cgit v1.3.1-sl0p