[linux] Linux DeviceLayer needs WiFi ConnectivityMgr

[turon]

Problem

The Linux device layer needs a ConnectivityMgr that handles a single, primary WiFi interface.

Proposed Solution

Implement the ConnectivityMgr with WiFi support.

Propose to interface directly to wpasupplicant.

Not in scope: conman, shill, or ubuntu / debian network manager.

Device layer assumes it is master of connectivity. Target is embedded Linux type devices such as RasPi or smart speaker.

Include instructions for testing on a laptop or workstation, including instructions on how to disable local network mgmt and give control to CHIP app.

• Status - 2020-06-10
  • Draft PR posted -- DBUS client API to wpasupplicant implemented
  • No ProvisioningService integration yet in CHIP -- only tested in Weave environment thus far
  • DBUS using gmain_loop -- may cause conflicts with ThreadStack -- team to coord offline
  • Suggest unit tests based with credentials loaded from file
  • Script to launch required services such as wpasupplicant
  • Difficult to define AP in simulation w/o hardware
  • Evaluate using mac80211 hwsim module

[turon]

@kghost status

• Can post PR of current code this week

  • Connect / Disconnect to WiFi network
  • ConnectivityMgr APIs implemented:
    • // WiFi station methods (implemented and manually tested)
    • // WiFi AP methods (not implemented -- split into separate PR)
    • // Internet connectivity methods (implemented and manually tested)

• Testing:

  • Manual testing on Linux machine
    • Start daemon, connect to existing WiFi, observing connected logs in wpasupplicant
  • No unit tests yet

[turon]

Status: #1066 PR posted

Open items:

• refactor to use generic dbus event sharing per [linux] dbus sharing design #1084
• align dbus schema definition with [WIP][linux] add ThreadStackManager for Linux Device layer #1147 -- use raw dbus lib
• conman vs. wpasupplicant discussion
• add testing with mock dbus service

[turon]

@kghost : blocking on #1084 to update to new dbus sharing framework.
also waiting for new test framework.

[turon]

@kghost : Once #1084, only need a few days to land since PR already uses gio.
@yunhanw-google : How do you test WiFi provisioning?
@kghost : No tests right now -- simulating WiFi not trivial
@turon : Manual testing on RasPi possible?
@kghost : Plan to add Mock provisioning service

[turon]

Status 2020-07-22:

• Was blocking dbus
• Have not had bandwidth to revisit since dbus PR merged
• reassigning to @yufengwangca -- will coordinate hand-off from @kghost over week
• testing challenges: unit tests can't perform end-to-end testing

[turon]

Status 2020-08-05:

• 2 PRs on Wifi merged
• 1 more in review
• next to add shell commands to control and test wifi manager

Opens:

• latest version of wpasupplicant is needed (v2.9) -- some APIs on older version (v2.6 on Ubuntu 18.04) don't work at all.
  • dbus API is available, but typical usage is via direct socket API

[yufengwangca]

All PRs to support WiFi over GDBus are merged. Next to add shell commands to control and test wifi manager which is tracked by #1696