DSR Steam Communication

This handles setting up/closing down connections, voice packets, other steam management stuff.

Reading https://partner.steamgames.com/doc/api may be helpful.

The two primary functions of interest are

void GetSteamData_Packet(DLNRD::SteamSessionLight *SteamSessionLight, DLNRD::SteamSessionMemberLight *SteamSessionMemberLight, uint param_3,uint8_t *data, uint data_len) @141088020

and

SendSteamData_Packet1 @1410B3F58
SendSteamData_Packet2 @1410B58DC
SendSteamData_Packet3 @1410B584C
(the type is stored in the byte at data+6 at this point)

For sending SteamData packets, the send function must be queued as a task in the SteamSession. This is done by SteamSessionLight_Queue_SendSteamMessage @14109cfd0.

For steam callbacks, you want to get the callback functions from the DLNRD::SteamSurveillance class, created by Init_DLNRD::SteamSurveillance @14107b750, and it's accessed by a global pointer at 141da1ab0.

Packet Types

This list is a Work-In-Progress. Underlined types are fully understood. The functions which handle each type are labeled ``sendTypeXSteamMessage`` and ``readparseTypeXSteamMessage``

Prolog for all packets:

char magic[4] = "VRXN";
uint16_t header = 0x584;
uint8_t type

(note this is converted to big endian before sending)

4. SessionPropertyReq

9. SyncSessionMemberRequest1

10. SyncSessionMemberRequest2

Regularly sent every few frames from the host to the guests
Contains a byte with the number of players the host sees present the world
Followed by each player's steam name, separated by 0x7

11. SendHostSearchResponse

12. P2PCommunicationResponse

First packet sent on start of session communication/initialization
Doesn't contain any data

13. OnAuthTicket

15. Response sent by guest to type 46 packet

24. SessionProperties

29. StartGame

30. CreateSessionVisibleTask

31. CreateSessionInvisibleTask

34. SyncSessionMemberResponse

Send as a response to type 10 from the guest to the host
Contains the number of players that are present in the type 10 packet but NOT present in the guest's world
If this value is >0 for a certain amount of time, the host will disconnect the guest with a 0xff000020 kickout reason
A desync detection and prevention measure

35. SearchHostResponse

36. ReceiveRandomNumber

Response automatically sent to type 12
optional dword of data

37. SyncSessionMemberRequest3

38. Response packet sent by host upon receiving type 15

42. NotifyLeavePlayer

46. KickOutTask

Packet requesting that you leave the session
data = uint32_t //usually 0xff000019

49. Unk2

50. LeaveMember