A codebase sweep for siblings of e282c059 (blocking network I/O parked
on the tokio runtime) found the openwrt fix was incomplete:
- openwrt.scan: scan_subnet is async in name only — up to 255 SEQUENTIAL
blocking TCP probes at 500ms each (~2 min on a /24 that silently
drops) plus a blocking SSH verify per candidate. One click of 'scan
for routers' held a worker for that whole time. Now spawn_blocking.
- provision-tollgate / scan-wifi / configure-wan still ran their SSH
exchanges inline; bounded_tcp caps each socket op but a session is
many sequential ops (provision runs opkg install over SSH), so worst
case was minutes. All three now spawn_blocking.
- network::check_dns: blocking glibc to_socket_addrs with no app-level
bound, on every Server-tab load via network.diagnostics. Against a
stale resolver — the moved-network case — that is 5-40s per refresh.
Now spawn_blocking plus a 5s cap, so the tile reports 'no DNS'
instead of hanging.
Verified false positives left alone: every other bare TcpStream::connect
targets 127.0.0.1 (fails instantly), and every remote reqwest client
already sets a timeout.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
