[vmmendozae]

What

System Link between Xendroid+ devices: consoles on the same Wi-Fi find and join each other's System Link games, as 360s do on one network. Devices on another subnet or a VPN (ZeroTier, Tailscale) are reached by naming their IP addresses.

Tested: Halo 3 System Link between two Android phones on one Wi-Fi — the game is found, joined and played.

How

Core (xenia/kernel/systemlink.{h,cc}, XSocket, XNet exports in xam_net.cc):

• Broadcasts go to the network's broadcast address (some Android networks drop 255.255.255.255) and, as unicasts, to named peers and to consoles heard from outside the local network. A console's own broadcasts are dropped.
• Ports below 1024 (Halo binds 1000/1001) bind as port + 10000 on the host and are translated both ways, so titles see the ports they asked for.
• XNetGetTitleXnAddr returns the device's address, its own Ethernet address and a per-console online identity; XNetXnAddrToInAddr / XNetInAddrToXnAddr, XNetXnAddrToMachineId, XNetLogonGetMachineID, XNetConnect / XNetGetConnectStatus, XNetCreateKey / XNetRegisterKey, the system link port and Ethernet link status are implemented.
• XNetQosListen / XNetQosLookup: hosts answer QoS probes over UDP (port 13074) with the data they publish.
• XLiveBaseGetNatType reports an open NAT with System Link on.
• System link hosts fill XSESSION_INFO in XSessionCreate.
• With System Link on, the log notes the first datagrams of each flow (addresses reduced to their last byte, as shared diagnostics hide them).

Everything is behind the new systemlink cvar (off by default); with it off, behaviour is unchanged.

App:

• Settings → System (Advanced): System link (LAN) and Other consoles (VPN).
• At launch, the device's IPv4 address, its network's broadcast address and a kept, random Ethernet address (02:22:48:…) go to the core as cvars; the Wi-Fi multicast lock is held while a game runs (ACCESS_WIFI_STATE, CHANGE_WIFI_MULTICAST_STATE).

Halo 3

Halo 3 refuses to connect to peers whose address is a plain IP unless its bundled patch "Allow public IP addresses." is on (Game patches). Without it the joiner finds the game but gives up with "Unable to join". The setting's description says so.

Tests

• SystemLinkTest (broadcast address math) and SettingCatalogTest pass.
• assembleDebug builds.

🤖 Generated with Claude Code

[vmmendozae]

trim.4679B37B-B726-4F7C-BBC0-C8BB9F516C09.MOV

[vmmendozae]

@phforner0 should i do something else for approval?

[phforner0]

@phforner0 should i do something else for approval?

Not for now, maybe just test it in more games if possible. I'm currently working on optimizations and fixing some bugs, so it will take a little while before I can review more in-depth and merge with me knowing that it won't break anything in the emulator. And my sincerest thanks for contributing to Xendroid Plus.

Or since I don't have much time available at the moment, after you test it in more games I'll merge it and let people test it as a preview build.

[vmmendozae]

It’s designed for games that use System Link or LAN for multiplayer; I’ve already tested it with Halo 3 and Gears of War 3 (Horde mode) and both work perfectly.

[vmmendozae]

trim.71E3BB71-4609-46B3-B549-1299CEE86874.MOV

Gears of war 3

[vmmendozae]

trim.CB595E25-3202-4516-8BE3-3DC1A6B4E614.MOV

Borderlands 2