user/ntpfs: implement a basic ntp client

time() will probably end up doing io. That sounded bad at first, but Plan 9
does that too (see /sys/src/libc/9sys/nsec.c), so it's probably fine.

I might need better service management soon. Also, dunno what it should return
before it makes contact with NTP.
I could implement RTC support, but eh. Doesn't feel that necessary.

I'll also need to remember how the hell threading works, so it can talk with
the ntp daemon on another thread.

1 files changed, 7 insertions, 4 deletions

diff --git a/src/cmd/netstack/udp.c b/src/cmd/netstack/udp.c
index 285af41..3b53b47 100644
--- a/src/cmd/netstack/udp.c
+++ b/src/cmd/netstack/udp.c
@@ -55,10 +55,13 @@ struct udp_conn *udpc_new(
 	c->lport = u.src ? u.src : 50000; // TODO randomize source ports
 	c->rport = u.dst;
 	if (arpcache_get(c->rip, &c->rmac) < 0) {
-		// TODO make arp request, wait for reply
-		warnx("IP not in ARP cache, unimplemented");
-		free(c);
-		return NULL;
+		// TODO wait for ARP reply
+		arp_request(c->rip);
+		if (arpcache_get(state.gateway, &c->rmac) < 0) {
+			warnx("neither target nor gateway not in ARP cache, dropping");
+			free(c);
+			return NULL;
+		}
 	}
 	c->on_recv = on_recv;
 	c->carg = carg;