simple-bw-scanner

It doesn't get simplier than this, folks.

Some quick notes to get you started

scanner.py is the client; server.py is the server. The server needs to run next to an "exit" relay (only needs to allow exiting to one IP+port on its own machine).

scanner.py is the client that ties everything together. It creates a circuit builder, relay list, and result dump. It creates a pool of worker threads to perform measurements. It currently performs one measurement per relay (in random order) and then quits. Obviously that (and a lot else) needs to change.

scanner.py: measure_relay is the function that runs in a worker thread to do a measurement. After building a two-hop circuit through the target relay and the helper "exit" relay and attaching a stream to that circuit, it tells the server to send 16 KiB. It times how long that takes. If it takes less than a second, it tells the server to send 10x as much and repeats. If it took longer than a second, it tells the server to send the amount that we predict would take just over 5s to send. Once we have a measurement that took longer than 5s, it sends the resulting speed (and other metadata) to the result dump.

The scanner still needs some work. For example, maybe we should only take a result that takes between 5s and 10s to retrieve instead of just greater than 5s. Maybe we need to take a small number of similarly sized measurements and only use the maximum as the result.

generate-v3bw.py takes the results from the last 5 days of measurements and generates a file ready for the bandwidth authorities to consume. It uses the median measuremnt from the last 5 days, which is a temporary thing until we think about what we actually want to do (max? EWMA?). It scales the results so that it can have comparible results to other systems (assuming they use the same scale).

lib/circuitbuilder.py Only one subclass of CircuitBuilder is used as of this writing, and that is GapsCircuitBuilder. Oddly enough, there are no gaps in the circuits we ask it to build.