# libSceRudp technical debt

### Silent stubs

- [sceRudpProcessEvents and sceRudpNetFlush](../../../core/libs/prx/libSceRudp/Export.cpp) (libSceRudp) - there is no reliable-UDP stack on the host, and every `sceRudpWrite`, `sceRudpRead` and `sceRudpGetStatus` call here reports a reset or idle context without queueing data, so no context ever holds pending data to process or send; both calls return success after `sceRudpInit` and `RUDP_ERROR_NOT_INITIALIZED` before it, as [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/main/src/core/libraries/rudp/rudp.cpp) returns OK from its stubs. PPSA03490 calls `sceRudpProcessEvents(0)` followed by `sceRudpNetFlush()` from its P2P service thread and ignores the first result; whether the real calls take parameters is unknown
- [sceRudpActivate](../../../core/libs/prx/libSceRudp/Export.cpp) (libSceRudp) - there is no reliable-UDP stack on the host to activate, so it returns success without doing anything, as [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/main/src/core/libraries/rudp/rudp.cpp) does for its own `sceRudpActivate`. PPSA01325 calls it with no arguments during start-up; what the console activates, and whether it reports an error before `sceRudpInit`, is unverified

### Unknown function info

- [sceRudpGetStatus](../../../core/libs/prx/libSceRudp/Export.cpp) - PPSA01521 passes an output pointer and byte count `0xF8`. Measured on a PS5 (firmware 13.60): the status is 0xF8 bytes; before `sceRudpInit` every call returns `RUDP_ERROR_NOT_INITIALIZED`, and after it a null pointer or a byte count of 0 or above 0xF8 returns `RUDP_ERROR_INVALID_ARGUMENT`. The layout matches `SceRudpStatus` in [Vita3K](https://github.com/AndnixSH/Vita3K-PS-Vita-OS-Fork/blob/master/vita3k/modules/SceRudp/SceLibRudp.cpp) with `currentContexts` at 0x64 and `allocs`, `frees`, `memCurrent` and `memPeak` at 0xC8 to 0xD4. Only `currentContexts` is reported: the traffic counters stay 0 because nothing is sent, and the allocator counters stay 0 because the library does not allocate from the title's pool (the console reports 6 allocations and 0x1260 bytes right after `sceRudpInit`, and 4 more allocations and 0x3F0 bytes per context). The console also writes `currentContexts` and the allocator counters when the byte count is smaller than their offset; only the requested bytes are written here.
- [sceRudpGetMaxSegmentSize](../../../core/libs/prx/libSceRudp/Export.cpp) (libSceRudp) - measured on a PS5 (firmware 13.60) in #3073: before `sceRudpInit` it returns `RUDP_ERROR_NOT_INITIALIZED` and leaves the value untouched, also for a null pointer; after it a null pointer returns `RUDP_ERROR_INVALID_ARGUMENT` and a valid one gets 1410 with result 0. The library keeps no configurable segment size (there is no `sceRudpSetMaxSegmentSize`), so 1410 is always reported. The `uint16_t*` parameter is inferred: the measurement does not show how many bytes the console writes, PPSA03490 passes a pointer to a 16-bit value and [RPCS3](https://github.com/RPCS3/rpcs3/blob/master/rpcs3/Emu/Cell/Modules/cellRudp.cpp) declares the PS3 `cellRudpSetMaxSegmentSize(u16 mss)`, so only 16 bits are written
- PPSA06888 imports declared without parameters, signatures unknown: [sceRudpEnableInternalIOThread2, sceRudpGetOption, sceRudpGetRemoteInfo](../../../core/libs/prx/libSceRudp/Export.cpp) (libSceRudp), imported by its bundled `Media/Plugins/SceRudp.prx` and not called during start-up. Names from the NID table of [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/main/src/core/libraries/rudp/rudp.cpp), which declares them without parameters too