Modem Authenticator (modem-authenticator-test) Package name

Modem Authenticator is a background C++ service that unlocks FCC restrictions on WWAN/modem modules. It is fully STRICT-confined (no --classic, no manual AppArmor tweaks) and Snap-Store publishable.

Event-driven design (no polling, no custom AppArmor, idle = zero CPU):

• Layer 3 (startup): the daemon unlocks once on boot / when the MBIM device first appears.
• Layer 1 (udev): snapd loads meta/udev/modem-manager.rules; when an MBIM device is (re-)enumerated -- USB control node (/dev/cdc-wdm*) OR PCIe control node (/dev/wwanmbim, kernel >= 5.14) -- via physical re-plug, power cycle, or firmware/link reset that drops the bus link, the kernel triggers the unlock oneshot service, which performs the FCC unlock and exits. (Old-kernel mhi_bus PCIe nodes are covered by a commented rule.)
• Layer 2 (systemd events): best-effort -- the daemon subscribes to systemd JobRemoved (ModemManager restart) and PrepareForSleep (resume) to re-unlock after events that do NOT drop the USB link. On the target snapd (2.76) there is no systemd D-Bus interface, so this layer degrades gracefully; startup + udev still cover the realistic triggers.

The unlock itself is sent via mbimcli directly to the device node (covered by the modem-manager plug). The FCC unlock key is HARDCODED in the binary (not externalised to a config file), overridable at runtime with -k.

A CLI tool (fccunlocker) is also provided for manual operation.

TEST BUILD (2026-08-13): published to practice the Snap Store workflow. Dell RW135/RW151 models use placeholder unlock keys in this release and are not yet supported.