Introduction: OpenWLANMap App

Hi,

My name is Lilli and I am studying technical computer science at the 6.th semester in Hamburg, Germany. In this summer, i will work on a new wardriving app for openwifi.su

OpenWifi.su is working on wifi positioning system. It uses an android app called OpenWLANMap App as the wardriving tool to collect wifi access points and sends it with the geolocation of the phone to the backend. The backend stores the data in database and also offers an API for non-GPS devices to request their positions based on the surrounding wifis.The backend currently uses triangulation technique on the numbers of access points it receives from the request device to calculate it’s geolocation.

A data entry from the wardriving app is currently BSSID + LATITUDE + LONGITUDE, which is stored temporarily effectively in local disk with 28 bytes (12 bytes for 12 characters of the MAC Address, 8 bytes for each latitude and longitude) before being uploaded to backend. The wardriver can do it manual or automatically. The app respects _nomap Wifi APs and does filter out some mobile hotspots on public transportation in europe. Unfortunately the app is hardly out of date. There are no developers working on the app and no updates for years. It does not run in new android devices. The OpenWifi.su has an amazing community of wardriver, over four thousands people. They have to keep very old phones to be able to run the app. But this community began to shrink in fact because peoples buy new phones which are not able to run the old app anymore.

I am so glad to get involved in the project and can spend my Google Summer of Code rewriting the app. Thank to freifunk community I was allowed to participate in the Wireless Community Weekend in Berlin in the community bonding period and had the chance to present my project, as well as talk to people about it and possible solutions for many problems. I spent the last weeks analysing the old app code and was talking a lot with my mentor about the old app performance and functionalities and ended up with many important decision about the design for new app. Here are some of them

  1. Wlocator is a service of getting GPS either from the device itself. In worst case where the GPS is undefined, it will send a request with the surrounding wifis to the Openwifi.su backend to ask for it’s geolocation. The service will run every n seconds
  2. Wifiscan is a service of scanning wifi access points. All the data of the AP such as BSSID, SSID, RSSI, frequency, channel , encrypted method, scan timestamp etc. will be scanned and display as user’s option. Necessary data will then be stored temporally local and later on uploaded to the database. The service will be stopped if the GPS of the device isn’t changed after n seconds in order to save device’s battery.
  3. Wififilter helps filter out: _nomap, mobile hotspot ( Call for help to collect mobile hotspot from different countries), ad_hoc network (I am working on it), collect open wifi to automatic connect and upload data if possible.
  4. Use trilateration or other techniques to define the location of the scanned AP better
  5. WifiUpload let users upload the data manual, automatic if internet available, automatic if only wifi available
  6. Extension: upload data to different APIs
  7. Saving resouces: stop scan service after n second of not changing GPS, put app in standby/doze mode if GPS does not change after n second, reduce brightness, kill app if battery critic
  8. Different languages available
  9. etc.

The plan for the next three months will be:

  1. Design new architecture for new app functionalities
  2. Design new UI
  3. Implement all logic functionalities
  4. JUNIT test + documentation

Stay tuned, I will update it soon.

L3I2