The host's arming check asked `ethtool` about every NIC, which is the wrong
question for Wi-Fi: the magic-packet trigger lives in nl80211's WoWLAN state,
and most wireless drivers print `Wake-on: d` whether or not it is armed. An
armed Wi-Fi host was therefore told it was NOT armed, and handed an
`ethtool -s wlan0 wol g` its driver rejects. A NIC with an nl80211 phy
(`/sys/class/net/<i>/phy80211`) is now asked `iw phy <phy> wowlan show`
instead, and the warning carries WoWLAN-correct guidance — `iw ... wowlan
enable magic-packet`, plus the NetworkManager
`802-11-wireless.wake-on-wlan magic` that survives a reconnect. Two fallbacks
for when `iw` can't answer (missing binary, driver without the command, or
privilege the user-level host service lacks): a POSITIVE ethtool reading
counts (brcmfmac & co do report there), a negative one never does, and sysfs
`device/power/wakeup` reading `disabled` is conclusive in the negative.
The client sender now emits from a socket bound to EACH non-loopback
interface's own address rather than leaving the path to the routing table. A
station in WoWLAN sleep stays associated and its AP buffers broadcast frames
for it until the next DTIM beacon — but only if the datagram reaches the
wireless segment at all, and with a VPN or mesh interface holding the default
route `255.255.255.255` never did. A failed bind falls back to the routed
socket, so no segment is lost.
Tests: `iw`/`ethtool` output parsing split from the commands so both are unit-
tested on any platform, and a new end-to-end test asserts a real listener
receives the 102 magic-packet bytes.
Verified on Linux (Ubuntu 26.04, 12 interfaces): `cargo fmt --all --check`,
`cargo clippy -p punktfunk-core -p punktfunk-host --all-targets --locked
-- -D warnings`, and both wol test sets green. NOT yet exercised against real
Wi-Fi hardware — no Wi-Fi Linux box was reachable.
enricobuehler