Network emulation

[neobrain]

Unclear what a good path forward here is. We don't want to implement all the purpose-specific protocols in a HLE-approach, but LLE is tricky to get working at all and it's unclear whether it's fast enough. Is there a good point in the stack that we could HLE to get the best of both worlds?

There are several possible points of attack:

• Application-facing networking ARM11 modules: HTTP, SSL, etc.
  • These all seem to refer to either SOC or NWM, so HLEing them seems redundant
• Low-level ARM11 modules: SOC, BOSS, CECD, parts of NWM
  • SOC/BOSS/CECD are implemented in terms of NWM, but their interface is easier to reverse-engineer
• Lowest-level ARM11 module: NWM
• WiFi firmware HLE
• WiFi firmware LLE

Prior art:

• melonDS translates WiFi frames to ethernet using libslirp: https://github.com/melonDS-emu/melonDS/blob/4ef2e1f4ccc2f8046b74b8562c8ee8ef5d33d0b0/src/WifiAP.cpp#L282
• Corgi3DS supports either LLE or HLE of the WiFi firmware, but only up to the point of initialization: https://github.com/PSI-Rockin/Corgi3DS/blob/master/src/core/arm11/wifi.cpp