Emulates just enough of the Xiaomi miIO "cloud" servers ott.io.mi.com and ot.io.mi.com to fix the really stupid problem of the qmi.powerstrip.v1 Smart Power Strip not updating status info when cut off from the internet, even returning broken JSON when it hasn't ever connected since bootup. "Just enough" being replying to client hellos and ping-pongs.

(Yeah, that's it, literally. This is probably one of the silliest firmware behaviors ever. The device doesn't actually need anything from the servers, but just this "get status" feature is broken in a weird way when the servers are unavailable. Wat?!)

Huge thanks to the authors of Dustcloud and python-miio.

PSA: Prefer devices with preflashed open source firmware or official OTA custom firmware installation!

• 100% Safe Rust
• no external crate dependencies, std library only
• no configuration
• no command line arguments

• cargo build --release, take the result at target/release/micloudfaker
• run that binary on some server, why not directly on your gateway/firewall
• configure DNS overrides:
  • e.g. on OPNsense, Unbound host overrides configured via the admin UI work fine
  • at least ott.io.mi.com and ot.io.mi.com both should return some particular address
    • just do this as a wildcard for everything under io.mi.com, why not
    • Dustcloud suggests 203.0.113.1 from the reserved test range
    • do not forget about this if you ever want something to communicate with the real servers again :D
• configure Destination NAT (port forwarding):
  • UDP that-reserved-address:8053 → your-server:8053
  • TCP that-reserved-address:80 → your-server:8053
    • to make TCP actually work on OPNsense, I've had to enable reflection on that NAT rule and tick "Automatic outbound NAT for Reflection" in "Firewall: Settings: Advanced". Otherwise I was getting an RST directly in response to every SYN-ACK, and lots of retransmissions and so on.
• power cycle the power strips (just deauthing them from Wi-Fi seems to leave DNS responses still cached, unfortunately)
• watch the output logspam
• test the affected functionality (e.g. by running miiocli -d powerstrip status)
• make the server run permanently (you can 2>/dev/null because the log isn't useful when not testing/debugging)
• enjoy!

Why not return the server address directly? Well, we use DNAT to redirect port 80 to 8053 so that we don't use a privileged port (so there's no need to mess with stuff like mac_portacl/Linux-capabilities or start as root). But I've encountered an extra reason: Unbound doesn't like returning local addreses in overrides, and very quickly starts returning the real ones. o_0 (Possibly related to the same addresses being used for the DHCP-hostname-to-local-domain thing.)

This is free and unencumbered software released into the public domain.
For more information, please refer to the UNLICENSE file or unlicense.org.