pan: Roadmap

[rolbk]

The goal is to eventually merge pan into scionproto/scion. However, the library is not yet production-ready. The following items need to be addressed before it is ready for wider use.

API Redesign

• Redesign API: State should be shared between connections without being global
  • Possible solution: Client struct encapsulating all shared state
    • See API discussion: pan: API design discussion #285
  • Remove global singleton host context (hardcodes SCIOND connection)
  • Remove global pathpool and stats singletons
  • Make path pool configurable (currently no configuration options)
  • Reduce long parameter lists via options pattern or shared client state

Type Cleanup

• Use original types: Use types from snet and other SCION components instead of redefining it
  • addr.IA
  • maybe pan.Path -> snet path.Path
  • possibly other types

PingingSelector Improvements

• API: SetActive() must be called at the correct time - refactor to call automatically
• Replace object-wide mutex with RWLock (currently locks for every packet sent)
• Fix reliability issues with proper testing
• Port internal ping package to use SCION CLI ping logic (currently copied from early SCION version)

Policy Improvements

• Fix "With" pattern: Calling WithPolicy() multiple times only sets the last policy - should build chain policy automatically

Code Organization

• Restructure into subpackages: Currently ~6000 LOC in 34 files, all in root package
• Drop RAINS support: Not actively used, adds maintenance burden

Testing

• Add unit tests: Improve test coverage across the library